xref: /rk3399_rockchip-uboot/README (revision b7381bb68ffac89bcc2f54d9f79f0831adf6a6a4)
1#
2# (C) Copyright 2000 - 2013
3# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4#
5# SPDX-License-Identifier:	GPL-2.0+
6#
7
8Summary:
9========
10
11This directory contains the source code for U-Boot, a boot loader for
12Embedded boards based on PowerPC, ARM, MIPS and several other
13processors, which can be installed in a boot ROM and used to
14initialize and test the hardware or to download and run application
15code.
16
17The development of U-Boot is closely related to Linux: some parts of
18the source code originate in the Linux source tree, we have some
19header files in common, and special provision has been made to
20support booting of Linux images.
21
22Some attention has been paid to make this software easily
23configurable and extendable. For instance, all monitor commands are
24implemented with the same call interface, so that it's very easy to
25add new commands. Also, instead of permanently adding rarely used
26code (for instance hardware test utilities) to the monitor, you can
27load and run it dynamically.
28
29
30Status:
31=======
32
33In general, all boards for which a configuration option exists in the
34Makefile have been tested to some extent and can be considered
35"working". In fact, many of them are used in production systems.
36
37In case of problems see the CHANGELOG file to find out who contributed
38the specific port. In addition, there are various MAINTAINERS files
39scattered throughout the U-Boot source identifying the people or
40companies responsible for various boards and subsystems.
41
42Note: As of August, 2010, there is no longer a CHANGELOG file in the
43actual U-Boot source tree; however, it can be created dynamically
44from the Git log using:
45
46	make CHANGELOG
47
48
49Where to get help:
50==================
51
52In case you have questions about, problems with or contributions for
53U-Boot, you should send a message to the U-Boot mailing list at
54<u-boot@lists.denx.de>. There is also an archive of previous traffic
55on the mailing list - please search the archive before asking FAQ's.
56Please see http://lists.denx.de/pipermail/u-boot and
57http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58
59
60Where to get source code:
61=========================
62
63The U-Boot source code is maintained in the Git repository at
64git://www.denx.de/git/u-boot.git ; you can browse it online at
65http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
66
67The "snapshot" links on this page allow you to download tarballs of
68any version you might be interested in. Official releases are also
69available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70directory.
71
72Pre-built (and tested) images are available from
73ftp://ftp.denx.de/pub/u-boot/images/
74
75
76Where we come from:
77===================
78
79- start from 8xxrom sources
80- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
81- clean up code
82- make it easier to add custom boards
83- make it possible to add other [PowerPC] CPUs
84- extend functions, especially:
85  * Provide extended interface to Linux boot loader
86  * S-Record download
87  * network boot
88  * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89- create ARMBoot project (http://sourceforge.net/projects/armboot)
90- add other CPU families (starting with ARM)
91- create U-Boot project (http://sourceforge.net/projects/u-boot)
92- current project page: see http://www.denx.de/wiki/U-Boot
93
94
95Names and Spelling:
96===================
97
98The "official" name of this project is "Das U-Boot". The spelling
99"U-Boot" shall be used in all written text (documentation, comments
100in source files etc.). Example:
101
102	This is the README file for the U-Boot project.
103
104File names etc. shall be based on the string "u-boot". Examples:
105
106	include/asm-ppc/u-boot.h
107
108	#include <asm/u-boot.h>
109
110Variable names, preprocessor constants etc. shall be either based on
111the string "u_boot" or on "U_BOOT". Example:
112
113	U_BOOT_VERSION		u_boot_logo
114	IH_OS_U_BOOT		u_boot_hush_start
115
116
117Versioning:
118===========
119
120Starting with the release in October 2008, the names of the releases
121were changed from numerical release numbers without deeper meaning
122into a time stamp based numbering. Regular releases are identified by
123names consisting of the calendar year and month of the release date.
124Additional fields (if present) indicate release candidates or bug fix
125releases in "stable" maintenance trees.
126
127Examples:
128	U-Boot v2009.11	    - Release November 2009
129	U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
130	U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
131
132
133Directory Hierarchy:
134====================
135
136/arch			Architecture specific files
137  /arc			Files generic to ARC architecture
138  /arm			Files generic to ARM architecture
139  /avr32		Files generic to AVR32 architecture
140  /blackfin		Files generic to Analog Devices Blackfin architecture
141  /m68k			Files generic to m68k architecture
142  /microblaze		Files generic to microblaze architecture
143  /mips			Files generic to MIPS architecture
144  /nds32		Files generic to NDS32 architecture
145  /nios2		Files generic to Altera NIOS2 architecture
146  /openrisc		Files generic to OpenRISC architecture
147  /powerpc		Files generic to PowerPC architecture
148  /sandbox		Files generic to HW-independent "sandbox"
149  /sh			Files generic to SH architecture
150  /sparc		Files generic to SPARC architecture
151  /x86			Files generic to x86 architecture
152/api			Machine/arch independent API for external apps
153/board			Board dependent files
154/cmd			U-Boot commands functions
155/common			Misc architecture independent functions
156/configs		Board default configuration files
157/disk			Code for disk drive partition handling
158/doc			Documentation (don't expect too much)
159/drivers		Commonly used device drivers
160/dts			Contains Makefile for building internal U-Boot fdt.
161/examples		Example code for standalone applications, etc.
162/fs			Filesystem code (cramfs, ext2, jffs2, etc.)
163/include		Header Files
164/lib			Library routines generic to all architectures
165/Licenses		Various license files
166/net			Networking code
167/post			Power On Self Test
168/scripts		Various build scripts and Makefiles
169/test			Various unit test files
170/tools			Tools to build S-Record or U-Boot images, etc.
171
172Software Configuration:
173=======================
174
175Configuration is usually done using C preprocessor defines; the
176rationale behind that is to avoid dead code whenever possible.
177
178There are two classes of configuration variables:
179
180* Configuration _OPTIONS_:
181  These are selectable by the user and have names beginning with
182  "CONFIG_".
183
184* Configuration _SETTINGS_:
185  These depend on the hardware etc. and should not be meddled with if
186  you don't know what you're doing; they have names beginning with
187  "CONFIG_SYS_".
188
189Previously, all configuration was done by hand, which involved creating
190symbolic links and editing configuration files manually. More recently,
191U-Boot has added the Kbuild infrastructure used by the Linux kernel,
192allowing you to use the "make menuconfig" command to configure your
193build.
194
195
196Selection of Processor Architecture and Board Type:
197---------------------------------------------------
198
199For all supported boards there are ready-to-use default
200configurations available; just type "make <board_name>_defconfig".
201
202Example: For a TQM823L module type:
203
204	cd u-boot
205	make TQM823L_defconfig
206
207Note: If you're looking for the default configuration file for a board
208you're sure used to be there but is now missing, check the file
209doc/README.scrapyard for a list of no longer supported boards.
210
211Sandbox Environment:
212--------------------
213
214U-Boot can be built natively to run on a Linux host using the 'sandbox'
215board. This allows feature development which is not board- or architecture-
216specific to be undertaken on a native platform. The sandbox is also used to
217run some of U-Boot's tests.
218
219See board/sandbox/README.sandbox for more details.
220
221
222Board Initialisation Flow:
223--------------------------
224
225This is the intended start-up flow for boards. This should apply for both
226SPL and U-Boot proper (i.e. they both follow the same rules).
227
228Note: "SPL" stands for "Secondary Program Loader," which is explained in
229more detail later in this file.
230
231At present, SPL mostly uses a separate code path, but the function names
232and roles of each function are the same. Some boards or architectures
233may not conform to this.  At least most ARM boards which use
234CONFIG_SPL_FRAMEWORK conform to this.
235
236Execution typically starts with an architecture-specific (and possibly
237CPU-specific) start.S file, such as:
238
239	- arch/arm/cpu/armv7/start.S
240	- arch/powerpc/cpu/mpc83xx/start.S
241	- arch/mips/cpu/start.S
242
243and so on. From there, three functions are called; the purpose and
244limitations of each of these functions are described below.
245
246lowlevel_init():
247	- purpose: essential init to permit execution to reach board_init_f()
248	- no global_data or BSS
249	- there is no stack (ARMv7 may have one but it will soon be removed)
250	- must not set up SDRAM or use console
251	- must only do the bare minimum to allow execution to continue to
252		board_init_f()
253	- this is almost never needed
254	- return normally from this function
255
256board_init_f():
257	- purpose: set up the machine ready for running board_init_r():
258		i.e. SDRAM and serial UART
259	- global_data is available
260	- stack is in SRAM
261	- BSS is not available, so you cannot use global/static variables,
262		only stack variables and global_data
263
264	Non-SPL-specific notes:
265	- dram_init() is called to set up DRAM. If already done in SPL this
266		can do nothing
267
268	SPL-specific notes:
269	- you can override the entire board_init_f() function with your own
270		version as needed.
271	- preloader_console_init() can be called here in extremis
272	- should set up SDRAM, and anything needed to make the UART work
273	- these is no need to clear BSS, it will be done by crt0.S
274	- must return normally from this function (don't call board_init_r()
275		directly)
276
277Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
278this point the stack and global_data are relocated to below
279CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
280memory.
281
282board_init_r():
283	- purpose: main execution, common code
284	- global_data is available
285	- SDRAM is available
286	- BSS is available, all static/global variables can be used
287	- execution eventually continues to main_loop()
288
289	Non-SPL-specific notes:
290	- U-Boot is relocated to the top of memory and is now running from
291		there.
292
293	SPL-specific notes:
294	- stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
295		CONFIG_SPL_STACK_R_ADDR points into SDRAM
296	- preloader_console_init() can be called here - typically this is
297		done by defining CONFIG_SPL_BOARD_INIT and then supplying a
298		spl_board_init() function containing this call
299	- loads U-Boot or (in falcon mode) Linux
300
301
302
303Configuration Options:
304----------------------
305
306Configuration depends on the combination of board and CPU type; all
307such information is kept in a configuration file
308"include/configs/<board_name>.h".
309
310Example: For a TQM823L module, all configuration settings are in
311"include/configs/TQM823L.h".
312
313
314Many of the options are named exactly as the corresponding Linux
315kernel configuration options. The intention is to make it easier to
316build a config tool - later.
317
318
319The following options need to be configured:
320
321- CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.
322
323- Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.
324
325- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
326		Define exactly one, e.g. CONFIG_ATSTK1002
327
328- Marvell Family Member
329		CONFIG_SYS_MVFS		- define it if you want to enable
330					  multiple fs option at one time
331					  for marvell soc family
332
333- 8xx CPU Options: (if using an MPC8xx CPU)
334		CONFIG_8xx_GCLK_FREQ	- deprecated: CPU clock if
335					  get_gclk_freq() cannot work
336					  e.g. if there is no 32KHz
337					  reference PIT/RTC clock
338		CONFIG_8xx_OSCLK	- PLL input clock (either EXTCLK
339					  or XTAL/EXTAL)
340
341- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342		CONFIG_SYS_8xx_CPUCLK_MIN
343		CONFIG_SYS_8xx_CPUCLK_MAX
344		CONFIG_8xx_CPUCLK_DEFAULT
345			See doc/README.MPC866
346
347		CONFIG_SYS_MEASURE_CPUCLK
348
349		Define this to measure the actual CPU clock instead
350		of relying on the correctness of the configured
351		values. Mostly useful for board bringup to make sure
352		the PLL is locked at the intended frequency. Note
353		that this requires a (stable) reference clock (32 kHz
354		RTC clock or CONFIG_SYS_8XX_XIN)
355
356		CONFIG_SYS_DELAYED_ICACHE
357
358		Define this option if you want to enable the
359		ICache only when Code runs from RAM.
360
361- 85xx CPU Options:
362		CONFIG_SYS_PPC64
363
364		Specifies that the core is a 64-bit PowerPC implementation (implements
365		the "64" category of the Power ISA). This is necessary for ePAPR
366		compliance, among other possible reasons.
367
368		CONFIG_SYS_FSL_TBCLK_DIV
369
370		Defines the core time base clock divider ratio compared to the
371		system clock.  On most PQ3 devices this is 8, on newer QorIQ
372		devices it can be 16 or 32.  The ratio varies from SoC to Soc.
373
374		CONFIG_SYS_FSL_PCIE_COMPAT
375
376		Defines the string to utilize when trying to match PCIe device
377		tree nodes for the given platform.
378
379		CONFIG_SYS_PPC_E500_DEBUG_TLB
380
381		Enables a temporary TLB entry to be used during boot to work
382		around limitations in e500v1 and e500v2 external debugger
383		support. This reduces the portions of the boot code where
384		breakpoints and single stepping do not work.  The value of this
385		symbol should be set to the TLB1 entry to be used for this
386		purpose.
387
388		CONFIG_SYS_FSL_ERRATUM_A004510
389
390		Enables a workaround for erratum A004510.  If set,
391		then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
393
394		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
396
397		Defines one or two SoC revisions (low 8 bits of SVR)
398		for which the A004510 workaround should be applied.
399
400		The rest of SVR is either not relevant to the decision
401		of whether the erratum is present (e.g. p2040 versus
402		p2041) or is implied by the build target, which controls
403		whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
404
405		See Freescale App Note 4493 for more information about
406		this erratum.
407
408		CONFIG_A003399_NOR_WORKAROUND
409		Enables a workaround for IFC erratum A003399. It is only
410		required during NOR boot.
411
412		CONFIG_A008044_WORKAROUND
413		Enables a workaround for T1040/T1042 erratum A008044. It is only
414		required during NAND boot and valid for Rev 1.0 SoC revision
415
416		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
417
418		This is the value to write into CCSR offset 0x18600
419		according to the A004510 workaround.
420
421		CONFIG_SYS_FSL_DSP_DDR_ADDR
422		This value denotes start offset of DDR memory which is
423		connected exclusively to the DSP cores.
424
425		CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
426		This value denotes start offset of M2 memory
427		which is directly connected to the DSP core.
428
429		CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
430		This value denotes start offset of M3 memory which is directly
431		connected to the DSP core.
432
433		CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
434		This value denotes start offset of DSP CCSR space.
435
436		CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
437		Single Source Clock is clocking mode present in some of FSL SoC's.
438		In this mode, a single differential clock is used to supply
439		clocks to the sysclock, ddrclock and usbclock.
440
441		CONFIG_SYS_CPC_REINIT_F
442		This CONFIG is defined when the CPC is configured as SRAM at the
443		time of U-Boot entry and is required to be re-initialized.
444
445		CONFIG_DEEP_SLEEP
446		Indicates this SoC supports deep sleep feature. If deep sleep is
447		supported, core will start to execute uboot when wakes up.
448
449- Generic CPU options:
450		CONFIG_SYS_GENERIC_GLOBAL_DATA
451		Defines global data is initialized in generic board board_init_f().
452		If this macro is defined, global data is created and cleared in
453		generic board board_init_f(). Without this macro, architecture/board
454		should initialize global data before calling board_init_f().
455
456		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
457
458		Defines the endianess of the CPU. Implementation of those
459		values is arch specific.
460
461		CONFIG_SYS_FSL_DDR
462		Freescale DDR driver in use. This type of DDR controller is
463		found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
464		SoCs.
465
466		CONFIG_SYS_FSL_DDR_ADDR
467		Freescale DDR memory-mapped register base.
468
469		CONFIG_SYS_FSL_DDR_EMU
470		Specify emulator support for DDR. Some DDR features such as
471		deskew training are not available.
472
473		CONFIG_SYS_FSL_DDRC_GEN1
474		Freescale DDR1 controller.
475
476		CONFIG_SYS_FSL_DDRC_GEN2
477		Freescale DDR2 controller.
478
479		CONFIG_SYS_FSL_DDRC_GEN3
480		Freescale DDR3 controller.
481
482		CONFIG_SYS_FSL_DDRC_GEN4
483		Freescale DDR4 controller.
484
485		CONFIG_SYS_FSL_DDRC_ARM_GEN3
486		Freescale DDR3 controller for ARM-based SoCs.
487
488		CONFIG_SYS_FSL_DDR1
489		Board config to use DDR1. It can be enabled for SoCs with
490		Freescale DDR1 or DDR2 controllers, depending on the board
491		implemetation.
492
493		CONFIG_SYS_FSL_DDR2
494		Board config to use DDR2. It can be enabled for SoCs with
495		Freescale DDR2 or DDR3 controllers, depending on the board
496		implementation.
497
498		CONFIG_SYS_FSL_DDR3
499		Board config to use DDR3. It can be enabled for SoCs with
500		Freescale DDR3 or DDR3L controllers.
501
502		CONFIG_SYS_FSL_DDR3L
503		Board config to use DDR3L. It can be enabled for SoCs with
504		DDR3L controllers.
505
506		CONFIG_SYS_FSL_DDR4
507		Board config to use DDR4. It can be enabled for SoCs with
508		DDR4 controllers.
509
510		CONFIG_SYS_FSL_IFC_BE
511		Defines the IFC controller register space as Big Endian
512
513		CONFIG_SYS_FSL_IFC_LE
514		Defines the IFC controller register space as Little Endian
515
516		CONFIG_SYS_FSL_PBL_PBI
517		It enables addition of RCW (Power on reset configuration) in built image.
518		Please refer doc/README.pblimage for more details
519
520		CONFIG_SYS_FSL_PBL_RCW
521		It adds PBI(pre-boot instructions) commands in u-boot build image.
522		PBI commands can be used to configure SoC before it starts the execution.
523		Please refer doc/README.pblimage for more details
524
525		CONFIG_SPL_FSL_PBL
526		It adds a target to create boot binary having SPL binary in PBI format
527		concatenated with u-boot binary.
528
529		CONFIG_SYS_FSL_DDR_BE
530		Defines the DDR controller register space as Big Endian
531
532		CONFIG_SYS_FSL_DDR_LE
533		Defines the DDR controller register space as Little Endian
534
535		CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
536		Physical address from the view of DDR controllers. It is the
537		same as CONFIG_SYS_DDR_SDRAM_BASE for  all Power SoCs. But
538		it could be different for ARM SoCs.
539
540		CONFIG_SYS_FSL_DDR_INTLV_256B
541		DDR controller interleaving on 256-byte. This is a special
542		interleaving mode, handled by Dickens for Freescale layerscape
543		SoCs with ARM core.
544
545		CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
546		Number of controllers used as main memory.
547
548		CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
549		Number of controllers used for other than main memory.
550
551		CONFIG_SYS_FSL_HAS_DP_DDR
552		Defines the SoC has DP-DDR used for DPAA.
553
554		CONFIG_SYS_FSL_SEC_BE
555		Defines the SEC controller register space as Big Endian
556
557		CONFIG_SYS_FSL_SEC_LE
558		Defines the SEC controller register space as Little Endian
559
560- MIPS CPU options:
561		CONFIG_SYS_INIT_SP_OFFSET
562
563		Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
564		pointer. This is needed for the temporary stack before
565		relocation.
566
567		CONFIG_SYS_MIPS_CACHE_MODE
568
569		Cache operation mode for the MIPS CPU.
570		See also arch/mips/include/asm/mipsregs.h.
571		Possible values are:
572			CONF_CM_CACHABLE_NO_WA
573			CONF_CM_CACHABLE_WA
574			CONF_CM_UNCACHED
575			CONF_CM_CACHABLE_NONCOHERENT
576			CONF_CM_CACHABLE_CE
577			CONF_CM_CACHABLE_COW
578			CONF_CM_CACHABLE_CUW
579			CONF_CM_CACHABLE_ACCELERATED
580
581		CONFIG_SYS_XWAY_EBU_BOOTCFG
582
583		Special option for Lantiq XWAY SoCs for booting from NOR flash.
584		See also arch/mips/cpu/mips32/start.S.
585
586		CONFIG_XWAY_SWAP_BYTES
587
588		Enable compilation of tools/xway-swap-bytes needed for Lantiq
589		XWAY SoCs for booting from NOR flash. The U-Boot image needs to
590		be swapped if a flash programmer is used.
591
592- ARM options:
593		CONFIG_SYS_EXCEPTION_VECTORS_HIGH
594
595		Select high exception vectors of the ARM core, e.g., do not
596		clear the V bit of the c1 register of CP15.
597
598		CONFIG_SYS_THUMB_BUILD
599
600		Use this flag to build U-Boot using the Thumb instruction
601		set for ARM architectures. Thumb instruction set provides
602		better code density. For ARM architectures that support
603		Thumb2 this flag will result in Thumb2 code generated by
604		GCC.
605
606		CONFIG_ARM_ERRATA_716044
607		CONFIG_ARM_ERRATA_742230
608		CONFIG_ARM_ERRATA_743622
609		CONFIG_ARM_ERRATA_751472
610		CONFIG_ARM_ERRATA_761320
611		CONFIG_ARM_ERRATA_773022
612		CONFIG_ARM_ERRATA_774769
613		CONFIG_ARM_ERRATA_794072
614
615		If set, the workarounds for these ARM errata are applied early
616		during U-Boot startup. Note that these options force the
617		workarounds to be applied; no CPU-type/version detection
618		exists, unlike the similar options in the Linux kernel. Do not
619		set these options unless they apply!
620
621		COUNTER_FREQUENCY
622		Generic timer clock source frequency.
623
624		COUNTER_FREQUENCY_REAL
625		Generic timer clock source frequency if the real clock is
626		different from COUNTER_FREQUENCY, and can only be determined
627		at run time.
628
629		NOTE: The following can be machine specific errata. These
630		do have ability to provide rudimentary version and machine
631		specific checks, but expect no product checks.
632		CONFIG_ARM_ERRATA_430973
633		CONFIG_ARM_ERRATA_454179
634		CONFIG_ARM_ERRATA_621766
635		CONFIG_ARM_ERRATA_798870
636		CONFIG_ARM_ERRATA_801819
637
638- Tegra SoC options:
639		CONFIG_TEGRA_SUPPORT_NON_SECURE
640
641		Support executing U-Boot in non-secure (NS) mode. Certain
642		impossible actions will be skipped if the CPU is in NS mode,
643		such as ARM architectural timer initialization.
644
645- Linux Kernel Interface:
646		CONFIG_CLOCKS_IN_MHZ
647
648		U-Boot stores all clock information in Hz
649		internally. For binary compatibility with older Linux
650		kernels (which expect the clocks passed in the
651		bd_info data to be in MHz) the environment variable
652		"clocks_in_mhz" can be defined so that U-Boot
653		converts clock data to MHZ before passing it to the
654		Linux kernel.
655		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
656		"clocks_in_mhz=1" is automatically included in the
657		default environment.
658
659		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]
660
661		When transferring memsize parameter to Linux, some versions
662		expect it to be in bytes, others in MB.
663		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
664
665		CONFIG_OF_LIBFDT
666
667		New kernel versions are expecting firmware settings to be
668		passed using flattened device trees (based on open firmware
669		concepts).
670
671		CONFIG_OF_LIBFDT
672		 * New libfdt-based support
673		 * Adds the "fdt" command
674		 * The bootm command automatically updates the fdt
675
676		OF_CPU - The proper name of the cpus node (only required for
677			MPC512X and MPC5xxx based boards).
678		OF_SOC - The proper name of the soc node (only required for
679			MPC512X and MPC5xxx based boards).
680		OF_TBCLK - The timebase frequency.
681		OF_STDOUT_PATH - The path to the console device
682
683		boards with QUICC Engines require OF_QE to set UCC MAC
684		addresses
685
686		CONFIG_OF_BOARD_SETUP
687
688		Board code has addition modification that it wants to make
689		to the flat device tree before handing it off to the kernel
690
691		CONFIG_OF_SYSTEM_SETUP
692
693		Other code has addition modification that it wants to make
694		to the flat device tree before handing it off to the kernel.
695		This causes ft_system_setup() to be called before booting
696		the kernel.
697
698		CONFIG_OF_IDE_FIXUP
699
700		U-Boot can detect if an IDE device is present or not.
701		If not, and this new config option is activated, U-Boot
702		removes the ATA node from the DTS before booting Linux,
703		so the Linux IDE driver does not probe the device and
704		crash. This is needed for buggy hardware (uc101) where
705		no pull down resistor is connected to the signal IDE5V_DD7.
706
707		CONFIG_MACH_TYPE	[relevant for ARM only][mandatory]
708
709		This setting is mandatory for all boards that have only one
710		machine type and must be used to specify the machine type
711		number as it appears in the ARM machine registry
712		(see http://www.arm.linux.org.uk/developer/machines/).
713		Only boards that have multiple machine types supported
714		in a single configuration file and the machine type is
715		runtime discoverable, do not have to use this setting.
716
717- vxWorks boot parameters:
718
719		bootvx constructs a valid bootline using the following
720		environments variables: bootdev, bootfile, ipaddr, netmask,
721		serverip, gatewayip, hostname, othbootargs.
722		It loads the vxWorks image pointed bootfile.
723
724		Note: If a "bootargs" environment is defined, it will overwride
725		the defaults discussed just above.
726
727- Cache Configuration:
728		CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
729		CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
730		CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
731
732- Cache Configuration for ARM:
733		CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
734				      controller
735		CONFIG_SYS_PL310_BASE - Physical base address of PL310
736					controller register space
737
738- Serial Ports:
739		CONFIG_PL010_SERIAL
740
741		Define this if you want support for Amba PrimeCell PL010 UARTs.
742
743		CONFIG_PL011_SERIAL
744
745		Define this if you want support for Amba PrimeCell PL011 UARTs.
746
747		CONFIG_PL011_CLOCK
748
749		If you have Amba PrimeCell PL011 UARTs, set this variable to
750		the clock speed of the UARTs.
751
752		CONFIG_PL01x_PORTS
753
754		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
755		define this to a list of base addresses for each (supported)
756		port. See e.g. include/configs/versatile.h
757
758		CONFIG_SERIAL_HW_FLOW_CONTROL
759
760		Define this variable to enable hw flow control in serial driver.
761		Current user of this option is drivers/serial/nsl16550.c driver
762
763- Console Interface:
764		Depending on board, define exactly one serial port
765		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
766		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
767		console by defining CONFIG_8xx_CONS_NONE
768
769		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
770		port routines must be defined elsewhere
771		(i.e. serial_init(), serial_getc(), ...)
772
773		CONFIG_CFB_CONSOLE
774		Enables console device for a color framebuffer. Needs following
775		defines (cf. smiLynxEM, i8042)
776			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
777						(default big endian)
778			VIDEO_HW_RECTFILL	graphic chip supports
779						rectangle fill
780						(cf. smiLynxEM)
781			VIDEO_HW_BITBLT		graphic chip supports
782						bit-blit (cf. smiLynxEM)
783			VIDEO_VISIBLE_COLS	visible pixel columns
784						(cols=pitch)
785			VIDEO_VISIBLE_ROWS	visible pixel rows
786			VIDEO_PIXEL_SIZE	bytes per pixel
787			VIDEO_DATA_FORMAT	graphic data format
788						(0-5, cf. cfb_console.c)
789			VIDEO_FB_ADRS		framebuffer address
790			VIDEO_KBD_INIT_FCT	keyboard int fct
791						(i.e. rx51_kp_init())
792			VIDEO_TSTC_FCT		test char fct
793						(i.e. rx51_kp_tstc)
794			VIDEO_GETC_FCT		get char fct
795						(i.e. rx51_kp_getc)
796			CONFIG_VIDEO_LOGO	display Linux logo in
797						upper left corner
798			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
799						linux_logo.h for logo.
800						Requires CONFIG_VIDEO_LOGO
801			CONFIG_CONSOLE_EXTRA_INFO
802						additional board info beside
803						the logo
804			CONFIG_HIDE_LOGO_VERSION
805						do not display bootloader
806						version string
807
808		When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
809		a limited number of ANSI escape sequences (cursor control,
810		erase functions and limited graphics rendition control).
811
812		When CONFIG_CFB_CONSOLE is defined, video console is
813		default i/o. Serial console can be forced with
814		environment 'console=serial'.
815
816		When CONFIG_SILENT_CONSOLE is defined, all console
817		messages (by U-Boot and Linux!) can be silenced with
818		the "silent" environment variable. See
819		doc/README.silent for more information.
820
821		CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
822			is 0x00.
823		CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
824			is 0xa0.
825
826- Console Baudrate:
827		CONFIG_BAUDRATE - in bps
828		Select one of the baudrates listed in
829		CONFIG_SYS_BAUDRATE_TABLE, see below.
830		CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
831
832- Console Rx buffer length
833		With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
834		the maximum receive buffer length for the SMC.
835		This option is actual only for 82xx and 8xx possible.
836		If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
837		must be defined, to setup the maximum idle timeout for
838		the SMC.
839
840- Pre-Console Buffer:
841		Prior to the console being initialised (i.e. serial UART
842		initialised etc) all console output is silently discarded.
843		Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
844		buffer any console messages prior to the console being
845		initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
846		bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
847		a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
848		bytes are output before the console is initialised, the
849		earlier bytes are discarded.
850
851		Note that when printing the buffer a copy is made on the
852		stack so CONFIG_PRE_CON_BUF_SZ must fit on the stack.
853
854		'Sane' compilers will generate smaller code if
855		CONFIG_PRE_CON_BUF_SZ is a power of 2
856
857- Autoboot Command:
858		CONFIG_BOOTCOMMAND
859		Only needed when CONFIG_BOOTDELAY is enabled;
860		define a command string that is automatically executed
861		when no character is read on the console interface
862		within "Boot Delay" after reset.
863
864		CONFIG_BOOTARGS
865		This can be used to pass arguments to the bootm
866		command. The value of CONFIG_BOOTARGS goes into the
867		environment value "bootargs".
868
869		CONFIG_RAMBOOT and CONFIG_NFSBOOT
870		The value of these goes into the environment as
871		"ramboot" and "nfsboot" respectively, and can be used
872		as a convenience, when switching between booting from
873		RAM and NFS.
874
875- Bootcount:
876		CONFIG_BOOTCOUNT_LIMIT
877		Implements a mechanism for detecting a repeating reboot
878		cycle, see:
879		http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
880
881		CONFIG_BOOTCOUNT_ENV
882		If no softreset save registers are found on the hardware
883		"bootcount" is stored in the environment. To prevent a
884		saveenv on all reboots, the environment variable
885		"upgrade_available" is used. If "upgrade_available" is
886		0, "bootcount" is always 0, if "upgrade_available" is
887		1 "bootcount" is incremented in the environment.
888		So the Userspace Applikation must set the "upgrade_available"
889		and "bootcount" variable to 0, if a boot was successfully.
890
891- Pre-Boot Commands:
892		CONFIG_PREBOOT
893
894		When this option is #defined, the existence of the
895		environment variable "preboot" will be checked
896		immediately before starting the CONFIG_BOOTDELAY
897		countdown and/or running the auto-boot command resp.
898		entering interactive mode.
899
900		This feature is especially useful when "preboot" is
901		automatically generated or modified. For an example
902		see the LWMON board specific code: here "preboot" is
903		modified when the user holds down a certain
904		combination of keys on the (special) keyboard when
905		booting the systems
906
907- Serial Download Echo Mode:
908		CONFIG_LOADS_ECHO
909		If defined to 1, all characters received during a
910		serial download (using the "loads" command) are
911		echoed back. This might be needed by some terminal
912		emulations (like "cu"), but may as well just take
913		time on others. This setting #define's the initial
914		value of the "loads_echo" environment variable.
915
916- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
917		CONFIG_KGDB_BAUDRATE
918		Select one of the baudrates listed in
919		CONFIG_SYS_BAUDRATE_TABLE, see below.
920
921- Monitor Functions:
922		Monitor commands can be included or excluded
923		from the build by using the #include files
924		<config_cmd_all.h> and #undef'ing unwanted
925		commands, or adding #define's for wanted commands.
926
927		The default command configuration includes all commands
928		except those marked below with a "*".
929
930		CONFIG_CMD_AES		  AES 128 CBC encrypt/decrypt
931		CONFIG_CMD_ASKENV	* ask for env variable
932		CONFIG_CMD_BDI		  bdinfo
933		CONFIG_CMD_BEDBUG	* Include BedBug Debugger
934		CONFIG_CMD_BMP		* BMP support
935		CONFIG_CMD_BSP		* Board specific commands
936		CONFIG_CMD_BOOTD	  bootd
937		CONFIG_CMD_BOOTI	* ARM64 Linux kernel Image support
938		CONFIG_CMD_CACHE	* icache, dcache
939		CONFIG_CMD_CLK   	* clock command support
940		CONFIG_CMD_CONSOLE	  coninfo
941		CONFIG_CMD_CRC32	* crc32
942		CONFIG_CMD_DATE		* support for RTC, date/time...
943		CONFIG_CMD_DHCP		* DHCP support
944		CONFIG_CMD_DIAG		* Diagnostics
945		CONFIG_CMD_DS4510	* ds4510 I2C gpio commands
946		CONFIG_CMD_DS4510_INFO	* ds4510 I2C info command
947		CONFIG_CMD_DS4510_MEM	* ds4510 I2C eeprom/sram commansd
948		CONFIG_CMD_DS4510_RST	* ds4510 I2C rst command
949		CONFIG_CMD_DTT		* Digital Therm and Thermostat
950		CONFIG_CMD_ECHO		  echo arguments
951		CONFIG_CMD_EDITENV	  edit env variable
952		CONFIG_CMD_EEPROM	* EEPROM read/write support
953		CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
954		CONFIG_CMD_ELF		* bootelf, bootvx
955		CONFIG_CMD_ENV_CALLBACK	* display details about env callbacks
956		CONFIG_CMD_ENV_FLAGS	* display details about env flags
957		CONFIG_CMD_ENV_EXISTS	* check existence of env variable
958		CONFIG_CMD_EXPORTENV	* export the environment
959		CONFIG_CMD_EXT2		* ext2 command support
960		CONFIG_CMD_EXT4		* ext4 command support
961		CONFIG_CMD_FS_GENERIC	* filesystem commands (e.g. load, ls)
962					  that work for multiple fs types
963		CONFIG_CMD_FS_UUID	* Look up a filesystem UUID
964		CONFIG_CMD_SAVEENV	  saveenv
965		CONFIG_CMD_FDC		* Floppy Disk Support
966		CONFIG_CMD_FAT		* FAT command support
967		CONFIG_CMD_FLASH	  flinfo, erase, protect
968		CONFIG_CMD_FPGA		  FPGA device initialization support
969		CONFIG_CMD_FUSE		* Device fuse support
970		CONFIG_CMD_GETTIME	* Get time since boot
971		CONFIG_CMD_GO		* the 'go' command (exec code)
972		CONFIG_CMD_GREPENV	* search environment
973		CONFIG_CMD_HASH		* calculate hash / digest
974		CONFIG_CMD_I2C		* I2C serial bus support
975		CONFIG_CMD_IDE		* IDE harddisk support
976		CONFIG_CMD_IMI		  iminfo
977		CONFIG_CMD_IMLS		  List all images found in NOR flash
978		CONFIG_CMD_IMLS_NAND	* List all images found in NAND flash
979		CONFIG_CMD_IMMAP	* IMMR dump support
980		CONFIG_CMD_IOTRACE	* I/O tracing for debugging
981		CONFIG_CMD_IMPORTENV	* import an environment
982		CONFIG_CMD_INI		* import data from an ini file into the env
983		CONFIG_CMD_IRQ		* irqinfo
984		CONFIG_CMD_ITEST	  Integer/string test of 2 values
985		CONFIG_CMD_JFFS2	* JFFS2 Support
986		CONFIG_CMD_KGDB		* kgdb
987		CONFIG_CMD_LDRINFO	* ldrinfo (display Blackfin loader)
988		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
989					  (169.254.*.*)
990		CONFIG_CMD_LOADB	  loadb
991		CONFIG_CMD_LOADS	  loads
992		CONFIG_CMD_MD5SUM	* print md5 message digest
993					  (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
994		CONFIG_CMD_MEMINFO	* Display detailed memory information
995		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
996					  loop, loopw
997		CONFIG_CMD_MEMTEST	* mtest
998		CONFIG_CMD_MISC		  Misc functions like sleep etc
999		CONFIG_CMD_MMC		* MMC memory mapped support
1000		CONFIG_CMD_MII		* MII utility commands
1001		CONFIG_CMD_MTDPARTS	* MTD partition support
1002		CONFIG_CMD_NAND		* NAND support
1003		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
1004		CONFIG_CMD_NFS		  NFS support
1005		CONFIG_CMD_PCA953X	* PCA953x I2C gpio commands
1006		CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1007		CONFIG_CMD_PCI		* pciinfo
1008		CONFIG_CMD_PCMCIA		* PCMCIA support
1009		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
1010					  host
1011		CONFIG_CMD_PORTIO	* Port I/O
1012		CONFIG_CMD_READ		* Read raw data from partition
1013		CONFIG_CMD_REGINFO	* Register dump
1014		CONFIG_CMD_RUN		  run command in env variable
1015		CONFIG_CMD_SANDBOX	* sb command to access sandbox features
1016		CONFIG_CMD_SAVES	* save S record dump
1017		CONFIG_SCSI		* SCSI Support
1018		CONFIG_CMD_SDRAM	* print SDRAM configuration information
1019					  (requires CONFIG_CMD_I2C)
1020		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
1021					  (4xx only)
1022		CONFIG_CMD_SF		* Read/write/erase SPI NOR flash
1023		CONFIG_CMD_SHA1SUM	* print sha1 memory digest
1024					  (requires CONFIG_CMD_MEMORY)
1025		CONFIG_CMD_SOFTSWITCH	* Soft switch setting command for BF60x
1026		CONFIG_CMD_SOURCE	  "source" command Support
1027		CONFIG_CMD_SPI		* SPI serial bus support
1028		CONFIG_CMD_TFTPSRV	* TFTP transfer in server mode
1029		CONFIG_CMD_TFTPPUT	* TFTP put command (upload)
1030		CONFIG_CMD_TIME		* run command and report execution time (ARM specific)
1031		CONFIG_CMD_TIMER	* access to the system tick timer
1032		CONFIG_CMD_USB		* USB support
1033		CONFIG_CMD_CDP		* Cisco Discover Protocol support
1034		CONFIG_CMD_MFSL		* Microblaze FSL support
1035		CONFIG_CMD_XIMG		  Load part of Multi Image
1036		CONFIG_CMD_UUID		* Generate random UUID or GUID string
1037
1038		EXAMPLE: If you want all functions except of network
1039		support you can write:
1040
1041		#include "config_cmd_all.h"
1042		#undef CONFIG_CMD_NET
1043
1044	Other Commands:
1045		fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1046
1047	Note:	Don't enable the "icache" and "dcache" commands
1048		(configuration option CONFIG_CMD_CACHE) unless you know
1049		what you (and your U-Boot users) are doing. Data
1050		cache cannot be enabled on systems like the 8xx or
1051		8260 (where accesses to the IMMR region must be
1052		uncached), and it cannot be disabled on all other
1053		systems where we (mis-) use the data cache to hold an
1054		initial stack and some data.
1055
1056
1057		XXX - this list needs to get updated!
1058
1059- Removal of commands
1060		If no commands are needed to boot, you can disable
1061		CONFIG_CMDLINE to remove them. In this case, the command line
1062		will not be available, and when U-Boot wants to execute the
1063		boot command (on start-up) it will call board_run_command()
1064		instead. This can reduce image size significantly for very
1065		simple boot procedures.
1066
1067- Regular expression support:
1068		CONFIG_REGEX
1069		If this variable is defined, U-Boot is linked against
1070		the SLRE (Super Light Regular Expression) library,
1071		which adds regex support to some commands, as for
1072		example "env grep" and "setexpr".
1073
1074- Device tree:
1075		CONFIG_OF_CONTROL
1076		If this variable is defined, U-Boot will use a device tree
1077		to configure its devices, instead of relying on statically
1078		compiled #defines in the board file. This option is
1079		experimental and only available on a few boards. The device
1080		tree is available in the global data as gd->fdt_blob.
1081
1082		U-Boot needs to get its device tree from somewhere. This can
1083		be done using one of the two options below:
1084
1085		CONFIG_OF_EMBED
1086		If this variable is defined, U-Boot will embed a device tree
1087		binary in its image. This device tree file should be in the
1088		board directory and called <soc>-<board>.dts. The binary file
1089		is then picked up in board_init_f() and made available through
1090		the global data structure as gd->blob.
1091
1092		CONFIG_OF_SEPARATE
1093		If this variable is defined, U-Boot will build a device tree
1094		binary. It will be called u-boot.dtb. Architecture-specific
1095		code will locate it at run-time. Generally this works by:
1096
1097			cat u-boot.bin u-boot.dtb >image.bin
1098
1099		and in fact, U-Boot does this for you, creating a file called
1100		u-boot-dtb.bin which is useful in the common case. You can
1101		still use the individual files if you need something more
1102		exotic.
1103
1104- Watchdog:
1105		CONFIG_WATCHDOG
1106		If this variable is defined, it enables watchdog
1107		support for the SoC. There must be support in the SoC
1108		specific code for a watchdog. For the 8xx and 8260
1109		CPUs, the SIU Watchdog feature is enabled in the SYPCR
1110		register.  When supported for a specific SoC is
1111		available, then no further board specific code should
1112		be needed to use it.
1113
1114		CONFIG_HW_WATCHDOG
1115		When using a watchdog circuitry external to the used
1116		SoC, then define this variable and provide board
1117		specific code for the "hw_watchdog_reset" function.
1118
1119		CONFIG_AT91_HW_WDT_TIMEOUT
1120		specify the timeout in seconds. default 2 seconds.
1121
1122- U-Boot Version:
1123		CONFIG_VERSION_VARIABLE
1124		If this variable is defined, an environment variable
1125		named "ver" is created by U-Boot showing the U-Boot
1126		version as printed by the "version" command.
1127		Any change to this variable will be reverted at the
1128		next reset.
1129
1130- Real-Time Clock:
1131
1132		When CONFIG_CMD_DATE is selected, the type of the RTC
1133		has to be selected, too. Define exactly one of the
1134		following options:
1135
1136		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
1137		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
1138		CONFIG_RTC_MC13XXX	- use MC13783 or MC13892 RTC
1139		CONFIG_RTC_MC146818	- use MC146818 RTC
1140		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
1141		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
1142		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
1143		CONFIG_RTC_DS1339	- use Maxim, Inc. DS1339 RTC
1144		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
1145		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
1146		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
1147		CONFIG_SYS_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
1148		CONFIG_SYS_RV3029_TCR	- enable trickle charger on
1149					  RV3029 RTC.
1150
1151		Note that if the RTC uses I2C, then the I2C interface
1152		must also be configured. See I2C Support, below.
1153
1154- GPIO Support:
1155		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
1156
1157		The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1158		chip-ngpio pairs that tell the PCA953X driver the number of
1159		pins supported by a particular chip.
1160
1161		Note that if the GPIO device uses I2C, then the I2C interface
1162		must also be configured. See I2C Support, below.
1163
1164- I/O tracing:
1165		When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1166		accesses and can checksum them or write a list of them out
1167		to memory. See the 'iotrace' command for details. This is
1168		useful for testing device drivers since it can confirm that
1169		the driver behaves the same way before and after a code
1170		change. Currently this is supported on sandbox and arm. To
1171		add support for your architecture, add '#include <iotrace.h>'
1172		to the bottom of arch/<arch>/include/asm/io.h and test.
1173
1174		Example output from the 'iotrace stats' command is below.
1175		Note that if the trace buffer is exhausted, the checksum will
1176		still continue to operate.
1177
1178			iotrace is enabled
1179			Start:  10000000	(buffer start address)
1180			Size:   00010000	(buffer size)
1181			Offset: 00000120	(current buffer offset)
1182			Output: 10000120	(start + offset)
1183			Count:  00000018	(number of trace records)
1184			CRC32:  9526fb66	(CRC32 of all trace records)
1185
1186- Timestamp Support:
1187
1188		When CONFIG_TIMESTAMP is selected, the timestamp
1189		(date and time) of an image is printed by image
1190		commands like bootm or iminfo. This option is
1191		automatically enabled when you select CONFIG_CMD_DATE .
1192
1193- Partition Labels (disklabels) Supported:
1194		Zero or more of the following:
1195		CONFIG_MAC_PARTITION   Apple's MacOS partition table.
1196		CONFIG_DOS_PARTITION   MS Dos partition table, traditional on the
1197				       Intel architecture, USB sticks, etc.
1198		CONFIG_ISO_PARTITION   ISO partition table, used on CDROM etc.
1199		CONFIG_EFI_PARTITION   GPT partition table, common when EFI is the
1200				       bootloader.  Note 2TB partition limit; see
1201				       disk/part_efi.c
1202		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.
1203
1204		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1205		CONFIG_SCSI) you must configure support for at
1206		least one non-MTD partition type as well.
1207
1208- IDE Reset method:
1209		CONFIG_IDE_RESET_ROUTINE - this is defined in several
1210		board configurations files but used nowhere!
1211
1212		CONFIG_IDE_RESET - is this is defined, IDE Reset will
1213		be performed by calling the function
1214			ide_set_reset(int reset)
1215		which has to be defined in a board specific file
1216
1217- ATAPI Support:
1218		CONFIG_ATAPI
1219
1220		Set this to enable ATAPI support.
1221
1222- LBA48 Support
1223		CONFIG_LBA48
1224
1225		Set this to enable support for disks larger than 137GB
1226		Also look at CONFIG_SYS_64BIT_LBA.
1227		Whithout these , LBA48 support uses 32bit variables and will 'only'
1228		support disks up to 2.1TB.
1229
1230		CONFIG_SYS_64BIT_LBA:
1231			When enabled, makes the IDE subsystem use 64bit sector addresses.
1232			Default is 32bit.
1233
1234- SCSI Support:
1235		At the moment only there is only support for the
1236		SYM53C8XX SCSI controller; define
1237		CONFIG_SCSI_SYM53C8XX to enable it.
1238
1239		CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1240		CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1241		CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1242		maximum numbers of LUNs, SCSI ID's and target
1243		devices.
1244		CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1245
1246		The environment variable 'scsidevs' is set to the number of
1247		SCSI devices found during the last scan.
1248
1249- NETWORK Support (PCI):
1250		CONFIG_E1000
1251		Support for Intel 8254x/8257x gigabit chips.
1252
1253		CONFIG_E1000_SPI
1254		Utility code for direct access to the SPI bus on Intel 8257x.
1255		This does not do anything useful unless you set at least one
1256		of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1257
1258		CONFIG_E1000_SPI_GENERIC
1259		Allow generic access to the SPI bus on the Intel 8257x, for
1260		example with the "sspi" command.
1261
1262		CONFIG_CMD_E1000
1263		Management command for E1000 devices.  When used on devices
1264		with SPI support you can reprogram the EEPROM from U-Boot.
1265
1266		CONFIG_EEPRO100
1267		Support for Intel 82557/82559/82559ER chips.
1268		Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1269		write routine for first time initialisation.
1270
1271		CONFIG_TULIP
1272		Support for Digital 2114x chips.
1273		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1274		modem chip initialisation (KS8761/QS6611).
1275
1276		CONFIG_NATSEMI
1277		Support for National dp83815 chips.
1278
1279		CONFIG_NS8382X
1280		Support for National dp8382[01] gigabit chips.
1281
1282- NETWORK Support (other):
1283
1284		CONFIG_DRIVER_AT91EMAC
1285		Support for AT91RM9200 EMAC.
1286
1287			CONFIG_RMII
1288			Define this to use reduced MII inteface
1289
1290			CONFIG_DRIVER_AT91EMAC_QUIET
1291			If this defined, the driver is quiet.
1292			The driver doen't show link status messages.
1293
1294		CONFIG_CALXEDA_XGMAC
1295		Support for the Calxeda XGMAC device
1296
1297		CONFIG_LAN91C96
1298		Support for SMSC's LAN91C96 chips.
1299
1300			CONFIG_LAN91C96_USE_32_BIT
1301			Define this to enable 32 bit addressing
1302
1303		CONFIG_SMC91111
1304		Support for SMSC's LAN91C111 chip
1305
1306			CONFIG_SMC91111_BASE
1307			Define this to hold the physical address
1308			of the device (I/O space)
1309
1310			CONFIG_SMC_USE_32_BIT
1311			Define this if data bus is 32 bits
1312
1313			CONFIG_SMC_USE_IOFUNCS
1314			Define this to use i/o functions instead of macros
1315			(some hardware wont work with macros)
1316
1317		CONFIG_DRIVER_TI_EMAC
1318		Support for davinci emac
1319
1320			CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1321			Define this if you have more then 3 PHYs.
1322
1323		CONFIG_FTGMAC100
1324		Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1325
1326			CONFIG_FTGMAC100_EGIGA
1327			Define this to use GE link update with gigabit PHY.
1328			Define this if FTGMAC100 is connected to gigabit PHY.
1329			If your system has 10/100 PHY only, it might not occur
1330			wrong behavior. Because PHY usually return timeout or
1331			useless data when polling gigabit status and gigabit
1332			control registers. This behavior won't affect the
1333			correctnessof 10/100 link speed update.
1334
1335		CONFIG_SMC911X
1336		Support for SMSC's LAN911x and LAN921x chips
1337
1338			CONFIG_SMC911X_BASE
1339			Define this to hold the physical address
1340			of the device (I/O space)
1341
1342			CONFIG_SMC911X_32_BIT
1343			Define this if data bus is 32 bits
1344
1345			CONFIG_SMC911X_16_BIT
1346			Define this if data bus is 16 bits. If your processor
1347			automatically converts one 32 bit word to two 16 bit
1348			words you may also try CONFIG_SMC911X_32_BIT.
1349
1350		CONFIG_SH_ETHER
1351		Support for Renesas on-chip Ethernet controller
1352
1353			CONFIG_SH_ETHER_USE_PORT
1354			Define the number of ports to be used
1355
1356			CONFIG_SH_ETHER_PHY_ADDR
1357			Define the ETH PHY's address
1358
1359			CONFIG_SH_ETHER_CACHE_WRITEBACK
1360			If this option is set, the driver enables cache flush.
1361
1362- PWM Support:
1363		CONFIG_PWM_IMX
1364		Support for PWM modul on the imx6.
1365
1366- TPM Support:
1367		CONFIG_TPM
1368		Support TPM devices.
1369
1370		CONFIG_TPM_TIS_INFINEON
1371		Support for Infineon i2c bus TPM devices. Only one device
1372		per system is supported at this time.
1373
1374			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1375			Define the burst count bytes upper limit
1376
1377		CONFIG_TPM_ST33ZP24
1378		Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1379
1380			CONFIG_TPM_ST33ZP24_I2C
1381			Support for STMicroelectronics ST33ZP24 I2C devices.
1382			Requires TPM_ST33ZP24 and I2C.
1383
1384			CONFIG_TPM_ST33ZP24_SPI
1385			Support for STMicroelectronics ST33ZP24 SPI devices.
1386			Requires TPM_ST33ZP24 and SPI.
1387
1388		CONFIG_TPM_ATMEL_TWI
1389		Support for Atmel TWI TPM device. Requires I2C support.
1390
1391		CONFIG_TPM_TIS_LPC
1392		Support for generic parallel port TPM devices. Only one device
1393		per system is supported at this time.
1394
1395			CONFIG_TPM_TIS_BASE_ADDRESS
1396			Base address where the generic TPM device is mapped
1397			to. Contemporary x86 systems usually map it at
1398			0xfed40000.
1399
1400		CONFIG_CMD_TPM
1401		Add tpm monitor functions.
1402		Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1403		provides monitor access to authorized functions.
1404
1405		CONFIG_TPM
1406		Define this to enable the TPM support library which provides
1407		functional interfaces to some TPM commands.
1408		Requires support for a TPM device.
1409
1410		CONFIG_TPM_AUTH_SESSIONS
1411		Define this to enable authorized functions in the TPM library.
1412		Requires CONFIG_TPM and CONFIG_SHA1.
1413
1414- USB Support:
1415		At the moment only the UHCI host controller is
1416		supported (PIP405, MIP405, MPC5200); define
1417		CONFIG_USB_UHCI to enable it.
1418		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1419		and define CONFIG_USB_STORAGE to enable the USB
1420		storage devices.
1421		Note:
1422		Supported are USB Keyboards and USB Floppy drives
1423		(TEAC FD-05PUB).
1424		MPC5200 USB requires additional defines:
1425			CONFIG_USB_CLOCK
1426				for 528 MHz Clock: 0x0001bbbb
1427			CONFIG_PSC3_USB
1428				for USB on PSC3
1429			CONFIG_USB_CONFIG
1430				for differential drivers: 0x00001000
1431				for single ended drivers: 0x00005000
1432				for differential drivers on PSC3: 0x00000100
1433				for single ended drivers on PSC3: 0x00004100
1434			CONFIG_SYS_USB_EVENT_POLL
1435				May be defined to allow interrupt polling
1436				instead of using asynchronous interrupts
1437
1438		CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1439		txfilltuning field in the EHCI controller on reset.
1440
1441		CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1442		HW module registers.
1443
1444- USB Device:
1445		Define the below if you wish to use the USB console.
1446		Once firmware is rebuilt from a serial console issue the
1447		command "setenv stdin usbtty; setenv stdout usbtty" and
1448		attach your USB cable. The Unix command "dmesg" should print
1449		it has found a new device. The environment variable usbtty
1450		can be set to gserial or cdc_acm to enable your device to
1451		appear to a USB host as a Linux gserial device or a
1452		Common Device Class Abstract Control Model serial device.
1453		If you select usbtty = gserial you should be able to enumerate
1454		a Linux host by
1455		# modprobe usbserial vendor=0xVendorID product=0xProductID
1456		else if using cdc_acm, simply setting the environment
1457		variable usbtty to be cdc_acm should suffice. The following
1458		might be defined in YourBoardName.h
1459
1460			CONFIG_USB_DEVICE
1461			Define this to build a UDC device
1462
1463			CONFIG_USB_TTY
1464			Define this to have a tty type of device available to
1465			talk to the UDC device
1466
1467			CONFIG_USBD_HS
1468			Define this to enable the high speed support for usb
1469			device and usbtty. If this feature is enabled, a routine
1470			int is_usbd_high_speed(void)
1471			also needs to be defined by the driver to dynamically poll
1472			whether the enumeration has succeded at high speed or full
1473			speed.
1474
1475			CONFIG_SYS_CONSOLE_IS_IN_ENV
1476			Define this if you want stdin, stdout &/or stderr to
1477			be set to usbtty.
1478
1479			mpc8xx:
1480				CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1481				Derive USB clock from external clock "blah"
1482				- CONFIG_SYS_USB_EXTC_CLK 0x02
1483
1484		If you have a USB-IF assigned VendorID then you may wish to
1485		define your own vendor specific values either in BoardName.h
1486		or directly in usbd_vendor_info.h. If you don't define
1487		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1488		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1489		should pretend to be a Linux device to it's target host.
1490
1491			CONFIG_USBD_MANUFACTURER
1492			Define this string as the name of your company for
1493			- CONFIG_USBD_MANUFACTURER "my company"
1494
1495			CONFIG_USBD_PRODUCT_NAME
1496			Define this string as the name of your product
1497			- CONFIG_USBD_PRODUCT_NAME "acme usb device"
1498
1499			CONFIG_USBD_VENDORID
1500			Define this as your assigned Vendor ID from the USB
1501			Implementors Forum. This *must* be a genuine Vendor ID
1502			to avoid polluting the USB namespace.
1503			- CONFIG_USBD_VENDORID 0xFFFF
1504
1505			CONFIG_USBD_PRODUCTID
1506			Define this as the unique Product ID
1507			for your device
1508			- CONFIG_USBD_PRODUCTID 0xFFFF
1509
1510- ULPI Layer Support:
1511		The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1512		the generic ULPI layer. The generic layer accesses the ULPI PHY
1513		via the platform viewport, so you need both the genric layer and
1514		the viewport enabled. Currently only Chipidea/ARC based
1515		viewport is supported.
1516		To enable the ULPI layer support, define CONFIG_USB_ULPI and
1517		CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1518		If your ULPI phy needs a different reference clock than the
1519		standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1520		the appropriate value in Hz.
1521
1522- MMC Support:
1523		The MMC controller on the Intel PXA is supported. To
1524		enable this define CONFIG_MMC. The MMC can be
1525		accessed from the boot prompt by mapping the device
1526		to physical memory similar to flash. Command line is
1527		enabled with CONFIG_CMD_MMC. The MMC driver also works with
1528		the FAT fs. This is enabled with CONFIG_CMD_FAT.
1529
1530		CONFIG_SH_MMCIF
1531		Support for Renesas on-chip MMCIF controller
1532
1533			CONFIG_SH_MMCIF_ADDR
1534			Define the base address of MMCIF registers
1535
1536			CONFIG_SH_MMCIF_CLK
1537			Define the clock frequency for MMCIF
1538
1539		CONFIG_GENERIC_MMC
1540		Enable the generic MMC driver
1541
1542		CONFIG_SUPPORT_EMMC_BOOT
1543		Enable some additional features of the eMMC boot partitions.
1544
1545		CONFIG_SUPPORT_EMMC_RPMB
1546		Enable the commands for reading, writing and programming the
1547		key for the Replay Protection Memory Block partition in eMMC.
1548
1549- USB Device Firmware Update (DFU) class support:
1550		CONFIG_USB_FUNCTION_DFU
1551		This enables the USB portion of the DFU USB class
1552
1553		CONFIG_CMD_DFU
1554		This enables the command "dfu" which is used to have
1555		U-Boot create a DFU class device via USB.  This command
1556		requires that the "dfu_alt_info" environment variable be
1557		set and define the alt settings to expose to the host.
1558
1559		CONFIG_DFU_MMC
1560		This enables support for exposing (e)MMC devices via DFU.
1561
1562		CONFIG_DFU_NAND
1563		This enables support for exposing NAND devices via DFU.
1564
1565		CONFIG_DFU_RAM
1566		This enables support for exposing RAM via DFU.
1567		Note: DFU spec refer to non-volatile memory usage, but
1568		allow usages beyond the scope of spec - here RAM usage,
1569		one that would help mostly the developer.
1570
1571		CONFIG_SYS_DFU_DATA_BUF_SIZE
1572		Dfu transfer uses a buffer before writing data to the
1573		raw storage device. Make the size (in bytes) of this buffer
1574		configurable. The size of this buffer is also configurable
1575		through the "dfu_bufsiz" environment variable.
1576
1577		CONFIG_SYS_DFU_MAX_FILE_SIZE
1578		When updating files rather than the raw storage device,
1579		we use a static buffer to copy the file into and then write
1580		the buffer once we've been given the whole file.  Define
1581		this to the maximum filesize (in bytes) for the buffer.
1582		Default is 4 MiB if undefined.
1583
1584		DFU_DEFAULT_POLL_TIMEOUT
1585		Poll timeout [ms], is the timeout a device can send to the
1586		host. The host must wait for this timeout before sending
1587		a subsequent DFU_GET_STATUS request to the device.
1588
1589		DFU_MANIFEST_POLL_TIMEOUT
1590		Poll timeout [ms], which the device sends to the host when
1591		entering dfuMANIFEST state. Host waits this timeout, before
1592		sending again an USB request to the device.
1593
1594- USB Device Android Fastboot support:
1595		CONFIG_USB_FUNCTION_FASTBOOT
1596		This enables the USB part of the fastboot gadget
1597
1598		CONFIG_CMD_FASTBOOT
1599		This enables the command "fastboot" which enables the Android
1600		fastboot mode for the platform's USB device. Fastboot is a USB
1601		protocol for downloading images, flashing and device control
1602		used on Android devices.
1603		See doc/README.android-fastboot for more information.
1604
1605		CONFIG_ANDROID_BOOT_IMAGE
1606		This enables support for booting images which use the Android
1607		image format header.
1608
1609		CONFIG_FASTBOOT_BUF_ADDR
1610		The fastboot protocol requires a large memory buffer for
1611		downloads. Define this to the starting RAM address to use for
1612		downloaded images.
1613
1614		CONFIG_FASTBOOT_BUF_SIZE
1615		The fastboot protocol requires a large memory buffer for
1616		downloads. This buffer should be as large as possible for a
1617		platform. Define this to the size available RAM for fastboot.
1618
1619		CONFIG_FASTBOOT_FLASH
1620		The fastboot protocol includes a "flash" command for writing
1621		the downloaded image to a non-volatile storage device. Define
1622		this to enable the "fastboot flash" command.
1623
1624		CONFIG_FASTBOOT_FLASH_MMC_DEV
1625		The fastboot "flash" command requires additional information
1626		regarding the non-volatile storage device. Define this to
1627		the eMMC device that fastboot should use to store the image.
1628
1629		CONFIG_FASTBOOT_GPT_NAME
1630		The fastboot "flash" command supports writing the downloaded
1631		image to the Protective MBR and the Primary GUID Partition
1632		Table. (Additionally, this downloaded image is post-processed
1633		to generate and write the Backup GUID Partition Table.)
1634		This occurs when the specified "partition name" on the
1635		"fastboot flash" command line matches this value.
1636		The default is "gpt" if undefined.
1637
1638		CONFIG_FASTBOOT_MBR_NAME
1639		The fastboot "flash" command supports writing the downloaded
1640		image to DOS MBR.
1641		This occurs when the "partition name" specified on the
1642		"fastboot flash" command line matches this value.
1643		If not defined the default value "mbr" is used.
1644
1645- Journaling Flash filesystem support:
1646		CONFIG_JFFS2_NAND
1647		Define these for a default partition on a NAND device
1648
1649		CONFIG_SYS_JFFS2_FIRST_SECTOR,
1650		CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1651		Define these for a default partition on a NOR device
1652
1653- FAT(File Allocation Table) filesystem write function support:
1654		CONFIG_FAT_WRITE
1655
1656		Define this to enable support for saving memory data as a
1657		file in FAT formatted partition.
1658
1659		This will also enable the command "fatwrite" enabling the
1660		user to write files to FAT.
1661
1662CBFS (Coreboot Filesystem) support
1663		CONFIG_CMD_CBFS
1664
1665		Define this to enable support for reading from a Coreboot
1666		filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1667		and cbfsload.
1668
1669- FAT(File Allocation Table) filesystem cluster size:
1670		CONFIG_FS_FAT_MAX_CLUSTSIZE
1671
1672		Define the max cluster size for fat operations else
1673		a default value of 65536 will be defined.
1674
1675- Keyboard Support:
1676		See Kconfig help for available keyboard drivers.
1677
1678		CONFIG_KEYBOARD
1679
1680		Define this to enable a custom keyboard support.
1681		This simply calls drv_keyboard_init() which must be
1682		defined in your board-specific files. This option is deprecated
1683		and is only used by novena. For new boards, use driver model
1684		instead.
1685
1686- Video support:
1687		CONFIG_VIDEO
1688
1689		Define this to enable video support (for output to
1690		video).
1691
1692		CONFIG_VIDEO_CT69000
1693
1694		Enable Chips & Technologies 69000 Video chip
1695
1696		CONFIG_VIDEO_SMI_LYNXEM
1697		Enable Silicon Motion SMI 712/710/810 Video chip. The
1698		video output is selected via environment 'videoout'
1699		(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1700		assumed.
1701
1702		For the CT69000 and SMI_LYNXEM drivers, videomode is
1703		selected via environment 'videomode'. Two different ways
1704		are possible:
1705		- "videomode=num"   'num' is a standard LiLo mode numbers.
1706		Following standard modes are supported	(* is default):
1707
1708		      Colors	640x480 800x600 1024x768 1152x864 1280x1024
1709		-------------+---------------------------------------------
1710		      8 bits |	0x301*	0x303	 0x305	  0x161	    0x307
1711		     15 bits |	0x310	0x313	 0x316	  0x162	    0x319
1712		     16 bits |	0x311	0x314	 0x317	  0x163	    0x31A
1713		     24 bits |	0x312	0x315	 0x318	    ?	    0x31B
1714		-------------+---------------------------------------------
1715		(i.e. setenv videomode 317; saveenv; reset;)
1716
1717		- "videomode=bootargs" all the video parameters are parsed
1718		from the bootargs. (See drivers/video/videomodes.c)
1719
1720
1721		CONFIG_VIDEO_SED13806
1722		Enable Epson SED13806 driver. This driver supports 8bpp
1723		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1724		or CONFIG_VIDEO_SED13806_16BPP
1725
1726		CONFIG_FSL_DIU_FB
1727		Enable the Freescale DIU video driver.	Reference boards for
1728		SOCs that have a DIU should define this macro to enable DIU
1729		support, and should also define these other macros:
1730
1731			CONFIG_SYS_DIU_ADDR
1732			CONFIG_VIDEO
1733			CONFIG_CMD_BMP
1734			CONFIG_CFB_CONSOLE
1735			CONFIG_VIDEO_SW_CURSOR
1736			CONFIG_VGA_AS_SINGLE_DEVICE
1737			CONFIG_VIDEO_LOGO
1738			CONFIG_VIDEO_BMP_LOGO
1739
1740		The DIU driver will look for the 'video-mode' environment
1741		variable, and if defined, enable the DIU as a console during
1742		boot.  See the documentation file doc/README.video for a
1743		description of this variable.
1744
1745- LCD Support:	CONFIG_LCD
1746
1747		Define this to enable LCD support (for output to LCD
1748		display); also select one of the supported displays
1749		by defining one of these:
1750
1751		CONFIG_ATMEL_LCD:
1752
1753			HITACHI TX09D70VM1CCA, 3.5", 240x320.
1754
1755		CONFIG_NEC_NL6448AC33:
1756
1757			NEC NL6448AC33-18. Active, color, single scan.
1758
1759		CONFIG_NEC_NL6448BC20
1760
1761			NEC NL6448BC20-08. 6.5", 640x480.
1762			Active, color, single scan.
1763
1764		CONFIG_NEC_NL6448BC33_54
1765
1766			NEC NL6448BC33-54. 10.4", 640x480.
1767			Active, color, single scan.
1768
1769		CONFIG_SHARP_16x9
1770
1771			Sharp 320x240. Active, color, single scan.
1772			It isn't 16x9, and I am not sure what it is.
1773
1774		CONFIG_SHARP_LQ64D341
1775
1776			Sharp LQ64D341 display, 640x480.
1777			Active, color, single scan.
1778
1779		CONFIG_HLD1045
1780
1781			HLD1045 display, 640x480.
1782			Active, color, single scan.
1783
1784		CONFIG_OPTREX_BW
1785
1786			Optrex	 CBL50840-2 NF-FW 99 22 M5
1787			or
1788			Hitachi	 LMG6912RPFC-00T
1789			or
1790			Hitachi	 SP14Q002
1791
1792			320x240. Black & white.
1793
1794		Normally display is black on white background; define
1795		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1796
1797		CONFIG_LCD_ALIGNMENT
1798
1799		Normally the LCD is page-aligned (typically 4KB). If this is
1800		defined then the LCD will be aligned to this value instead.
1801		For ARM it is sometimes useful to use MMU_SECTION_SIZE
1802		here, since it is cheaper to change data cache settings on
1803		a per-section basis.
1804
1805		CONFIG_CONSOLE_SCROLL_LINES
1806
1807		When the console need to be scrolled, this is the number of
1808		lines to scroll by. It defaults to 1. Increasing this makes
1809		the console jump but can help speed up operation when scrolling
1810		is slow.
1811
1812		CONFIG_LCD_ROTATION
1813
1814		Sometimes, for example if the display is mounted in portrait
1815		mode or even if it's mounted landscape but rotated by 180degree,
1816		we need to rotate our content of the display relative to the
1817		framebuffer, so that user can read the messages which are
1818		printed out.
1819		Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1820		initialized with a given rotation from "vl_rot" out of
1821		"vidinfo_t" which is provided by the board specific code.
1822		The value for vl_rot is coded as following (matching to
1823		fbcon=rotate:<n> linux-kernel commandline):
1824		0 = no rotation respectively 0 degree
1825		1 = 90 degree rotation
1826		2 = 180 degree rotation
1827		3 = 270 degree rotation
1828
1829		If CONFIG_LCD_ROTATION is not defined, the console will be
1830		initialized with 0degree rotation.
1831
1832		CONFIG_LCD_BMP_RLE8
1833
1834		Support drawing of RLE8-compressed bitmaps on the LCD.
1835
1836		CONFIG_I2C_EDID
1837
1838		Enables an 'i2c edid' command which can read EDID
1839		information over I2C from an attached LCD display.
1840
1841- Splash Screen Support: CONFIG_SPLASH_SCREEN
1842
1843		If this option is set, the environment is checked for
1844		a variable "splashimage". If found, the usual display
1845		of logo, copyright and system information on the LCD
1846		is suppressed and the BMP image at the address
1847		specified in "splashimage" is loaded instead. The
1848		console is redirected to the "nulldev", too. This
1849		allows for a "silent" boot where a splash screen is
1850		loaded very quickly after power-on.
1851
1852		CONFIG_SPLASHIMAGE_GUARD
1853
1854		If this option is set, then U-Boot will prevent the environment
1855		variable "splashimage" from being set to a problematic address
1856		(see doc/README.displaying-bmps).
1857		This option is useful for targets where, due to alignment
1858		restrictions, an improperly aligned BMP image will cause a data
1859		abort. If you think you will not have problems with unaligned
1860		accesses (for example because your toolchain prevents them)
1861		there is no need to set this option.
1862
1863		CONFIG_SPLASH_SCREEN_ALIGN
1864
1865		If this option is set the splash image can be freely positioned
1866		on the screen. Environment variable "splashpos" specifies the
1867		position as "x,y". If a positive number is given it is used as
1868		number of pixel from left/top. If a negative number is given it
1869		is used as number of pixel from right/bottom. You can also
1870		specify 'm' for centering the image.
1871
1872		Example:
1873		setenv splashpos m,m
1874			=> image at center of screen
1875
1876		setenv splashpos 30,20
1877			=> image at x = 30 and y = 20
1878
1879		setenv splashpos -10,m
1880			=> vertically centered image
1881			   at x = dspWidth - bmpWidth - 9
1882
1883- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1884
1885		If this option is set, additionally to standard BMP
1886		images, gzipped BMP images can be displayed via the
1887		splashscreen support or the bmp command.
1888
1889- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1890
1891		If this option is set, 8-bit RLE compressed BMP images
1892		can be displayed via the splashscreen support or the
1893		bmp command.
1894
1895- Do compressing for memory range:
1896		CONFIG_CMD_ZIP
1897
1898		If this option is set, it would use zlib deflate method
1899		to compress the specified memory at its best effort.
1900
1901- Compression support:
1902		CONFIG_GZIP
1903
1904		Enabled by default to support gzip compressed images.
1905
1906		CONFIG_BZIP2
1907
1908		If this option is set, support for bzip2 compressed
1909		images is included. If not, only uncompressed and gzip
1910		compressed images are supported.
1911
1912		NOTE: the bzip2 algorithm requires a lot of RAM, so
1913		the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1914		be at least 4MB.
1915
1916		CONFIG_LZMA
1917
1918		If this option is set, support for lzma compressed
1919		images is included.
1920
1921		Note: The LZMA algorithm adds between 2 and 4KB of code and it
1922		requires an amount of dynamic memory that is given by the
1923		formula:
1924
1925			(1846 + 768 << (lc + lp)) * sizeof(uint16)
1926
1927		Where lc and lp stand for, respectively, Literal context bits
1928		and Literal pos bits.
1929
1930		This value is upper-bounded by 14MB in the worst case. Anyway,
1931		for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1932		total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1933		a very small buffer.
1934
1935		Use the lzmainfo tool to determinate the lc and lp values and
1936		then calculate the amount of needed dynamic memory (ensuring
1937		the appropriate CONFIG_SYS_MALLOC_LEN value).
1938
1939		CONFIG_LZO
1940
1941		If this option is set, support for LZO compressed images
1942		is included.
1943
1944- MII/PHY support:
1945		CONFIG_PHY_ADDR
1946
1947		The address of PHY on MII bus.
1948
1949		CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1950
1951		The clock frequency of the MII bus
1952
1953		CONFIG_PHY_GIGE
1954
1955		If this option is set, support for speed/duplex
1956		detection of gigabit PHY is included.
1957
1958		CONFIG_PHY_RESET_DELAY
1959
1960		Some PHY like Intel LXT971A need extra delay after
1961		reset before any MII register access is possible.
1962		For such PHY, set this option to the usec delay
1963		required. (minimum 300usec for LXT971A)
1964
1965		CONFIG_PHY_CMD_DELAY (ppc4xx)
1966
1967		Some PHY like Intel LXT971A need extra delay after
1968		command issued before MII status register can be read
1969
1970- IP address:
1971		CONFIG_IPADDR
1972
1973		Define a default value for the IP address to use for
1974		the default Ethernet interface, in case this is not
1975		determined through e.g. bootp.
1976		(Environment variable "ipaddr")
1977
1978- Server IP address:
1979		CONFIG_SERVERIP
1980
1981		Defines a default value for the IP address of a TFTP
1982		server to contact when using the "tftboot" command.
1983		(Environment variable "serverip")
1984
1985		CONFIG_KEEP_SERVERADDR
1986
1987		Keeps the server's MAC address, in the env 'serveraddr'
1988		for passing to bootargs (like Linux's netconsole option)
1989
1990- Gateway IP address:
1991		CONFIG_GATEWAYIP
1992
1993		Defines a default value for the IP address of the
1994		default router where packets to other networks are
1995		sent to.
1996		(Environment variable "gatewayip")
1997
1998- Subnet mask:
1999		CONFIG_NETMASK
2000
2001		Defines a default value for the subnet mask (or
2002		routing prefix) which is used to determine if an IP
2003		address belongs to the local subnet or needs to be
2004		forwarded through a router.
2005		(Environment variable "netmask")
2006
2007- Multicast TFTP Mode:
2008		CONFIG_MCAST_TFTP
2009
2010		Defines whether you want to support multicast TFTP as per
2011		rfc-2090; for example to work with atftp.  Lets lots of targets
2012		tftp down the same boot image concurrently.  Note: the Ethernet
2013		driver in use must provide a function: mcast() to join/leave a
2014		multicast group.
2015
2016- BOOTP Recovery Mode:
2017		CONFIG_BOOTP_RANDOM_DELAY
2018
2019		If you have many targets in a network that try to
2020		boot using BOOTP, you may want to avoid that all
2021		systems send out BOOTP requests at precisely the same
2022		moment (which would happen for instance at recovery
2023		from a power failure, when all systems will try to
2024		boot, thus flooding the BOOTP server. Defining
2025		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2026		inserted before sending out BOOTP requests. The
2027		following delays are inserted then:
2028
2029		1st BOOTP request:	delay 0 ... 1 sec
2030		2nd BOOTP request:	delay 0 ... 2 sec
2031		3rd BOOTP request:	delay 0 ... 4 sec
2032		4th and following
2033		BOOTP requests:		delay 0 ... 8 sec
2034
2035		CONFIG_BOOTP_ID_CACHE_SIZE
2036
2037		BOOTP packets are uniquely identified using a 32-bit ID. The
2038		server will copy the ID from client requests to responses and
2039		U-Boot will use this to determine if it is the destination of
2040		an incoming response. Some servers will check that addresses
2041		aren't in use before handing them out (usually using an ARP
2042		ping) and therefore take up to a few hundred milliseconds to
2043		respond. Network congestion may also influence the time it
2044		takes for a response to make it back to the client. If that
2045		time is too long, U-Boot will retransmit requests. In order
2046		to allow earlier responses to still be accepted after these
2047		retransmissions, U-Boot's BOOTP client keeps a small cache of
2048		IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2049		cache. The default is to keep IDs for up to four outstanding
2050		requests. Increasing this will allow U-Boot to accept offers
2051		from a BOOTP client in networks with unusually high latency.
2052
2053- DHCP Advanced Options:
2054		You can fine tune the DHCP functionality by defining
2055		CONFIG_BOOTP_* symbols:
2056
2057		CONFIG_BOOTP_SUBNETMASK
2058		CONFIG_BOOTP_GATEWAY
2059		CONFIG_BOOTP_HOSTNAME
2060		CONFIG_BOOTP_NISDOMAIN
2061		CONFIG_BOOTP_BOOTPATH
2062		CONFIG_BOOTP_BOOTFILESIZE
2063		CONFIG_BOOTP_DNS
2064		CONFIG_BOOTP_DNS2
2065		CONFIG_BOOTP_SEND_HOSTNAME
2066		CONFIG_BOOTP_NTPSERVER
2067		CONFIG_BOOTP_TIMEOFFSET
2068		CONFIG_BOOTP_VENDOREX
2069		CONFIG_BOOTP_MAY_FAIL
2070
2071		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2072		environment variable, not the BOOTP server.
2073
2074		CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2075		after the configured retry count, the call will fail
2076		instead of starting over.  This can be used to fail over
2077		to Link-local IP address configuration if the DHCP server
2078		is not available.
2079
2080		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2081		serverip from a DHCP server, it is possible that more
2082		than one DNS serverip is offered to the client.
2083		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2084		serverip will be stored in the additional environment
2085		variable "dnsip2". The first DNS serverip is always
2086		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2087		is defined.
2088
2089		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2090		to do a dynamic update of a DNS server. To do this, they
2091		need the hostname of the DHCP requester.
2092		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2093		of the "hostname" environment variable is passed as
2094		option 12 to the DHCP server.
2095
2096		CONFIG_BOOTP_DHCP_REQUEST_DELAY
2097
2098		A 32bit value in microseconds for a delay between
2099		receiving a "DHCP Offer" and sending the "DHCP Request".
2100		This fixes a problem with certain DHCP servers that don't
2101		respond 100% of the time to a "DHCP request". E.g. On an
2102		AT91RM9200 processor running at 180MHz, this delay needed
2103		to be *at least* 15,000 usec before a Windows Server 2003
2104		DHCP server would reply 100% of the time. I recommend at
2105		least 50,000 usec to be safe. The alternative is to hope
2106		that one of the retries will be successful but note that
2107		the DHCP timeout and retry process takes a longer than
2108		this delay.
2109
2110 - Link-local IP address negotiation:
2111		Negotiate with other link-local clients on the local network
2112		for an address that doesn't require explicit configuration.
2113		This is especially useful if a DHCP server cannot be guaranteed
2114		to exist in all environments that the device must operate.
2115
2116		See doc/README.link-local for more information.
2117
2118 - CDP Options:
2119		CONFIG_CDP_DEVICE_ID
2120
2121		The device id used in CDP trigger frames.
2122
2123		CONFIG_CDP_DEVICE_ID_PREFIX
2124
2125		A two character string which is prefixed to the MAC address
2126		of the device.
2127
2128		CONFIG_CDP_PORT_ID
2129
2130		A printf format string which contains the ascii name of
2131		the port. Normally is set to "eth%d" which sets
2132		eth0 for the first Ethernet, eth1 for the second etc.
2133
2134		CONFIG_CDP_CAPABILITIES
2135
2136		A 32bit integer which indicates the device capabilities;
2137		0x00000010 for a normal host which does not forwards.
2138
2139		CONFIG_CDP_VERSION
2140
2141		An ascii string containing the version of the software.
2142
2143		CONFIG_CDP_PLATFORM
2144
2145		An ascii string containing the name of the platform.
2146
2147		CONFIG_CDP_TRIGGER
2148
2149		A 32bit integer sent on the trigger.
2150
2151		CONFIG_CDP_POWER_CONSUMPTION
2152
2153		A 16bit integer containing the power consumption of the
2154		device in .1 of milliwatts.
2155
2156		CONFIG_CDP_APPLIANCE_VLAN_TYPE
2157
2158		A byte containing the id of the VLAN.
2159
2160- Status LED:	CONFIG_STATUS_LED
2161
2162		Several configurations allow to display the current
2163		status using a LED. For instance, the LED will blink
2164		fast while running U-Boot code, stop blinking as
2165		soon as a reply to a BOOTP request was received, and
2166		start blinking slow once the Linux kernel is running
2167		(supported by a status LED driver in the Linux
2168		kernel). Defining CONFIG_STATUS_LED enables this
2169		feature in U-Boot.
2170
2171		Additional options:
2172
2173		CONFIG_GPIO_LED
2174		The status LED can be connected to a GPIO pin.
2175		In such cases, the gpio_led driver can be used as a
2176		status LED backend implementation. Define CONFIG_GPIO_LED
2177		to include the gpio_led driver in the U-Boot binary.
2178
2179		CONFIG_GPIO_LED_INVERTED_TABLE
2180		Some GPIO connected LEDs may have inverted polarity in which
2181		case the GPIO high value corresponds to LED off state and
2182		GPIO low value corresponds to LED on state.
2183		In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2184		with a list of GPIO LEDs that have inverted polarity.
2185
2186- CAN Support:	CONFIG_CAN_DRIVER
2187
2188		Defining CONFIG_CAN_DRIVER enables CAN driver support
2189		on those systems that support this (optional)
2190		feature, like the TQM8xxL modules.
2191
2192- I2C Support:	CONFIG_SYS_I2C
2193
2194		This enable the NEW i2c subsystem, and will allow you to use
2195		i2c commands at the u-boot command line (as long as you set
2196		CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2197		based realtime clock chips or other i2c devices. See
2198		common/cmd_i2c.c for a description of the command line
2199		interface.
2200
2201		ported i2c driver to the new framework:
2202		- drivers/i2c/soft_i2c.c:
2203		  - activate first bus with CONFIG_SYS_I2C_SOFT define
2204		    CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2205		    for defining speed and slave address
2206		  - activate second bus with I2C_SOFT_DECLARATIONS2 define
2207		    CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2208		    for defining speed and slave address
2209		  - activate third bus with I2C_SOFT_DECLARATIONS3 define
2210		    CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2211		    for defining speed and slave address
2212		  - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2213		    CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2214		    for defining speed and slave address
2215
2216		- drivers/i2c/fsl_i2c.c:
2217		  - activate i2c driver with CONFIG_SYS_I2C_FSL
2218		    define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2219		    offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2220		    CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2221		    bus.
2222		  - If your board supports a second fsl i2c bus, define
2223		    CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2224		    CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2225		    CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2226		    second bus.
2227
2228		- drivers/i2c/tegra_i2c.c:
2229		  - activate this driver with CONFIG_SYS_I2C_TEGRA
2230		  - This driver adds 4 i2c buses with a fix speed from
2231		    100000 and the slave addr 0!
2232
2233		- drivers/i2c/ppc4xx_i2c.c
2234		  - activate this driver with CONFIG_SYS_I2C_PPC4XX
2235		  - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2236		  - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2237
2238		- drivers/i2c/i2c_mxc.c
2239		  - activate this driver with CONFIG_SYS_I2C_MXC
2240		  - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2241		  - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2242		  - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2243		  - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2244		  - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2245		  - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2246		  - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2247		  - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2248		  - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2249		  - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2250		  - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2251		  - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2252		If those defines are not set, default value is 100000
2253		for speed, and 0 for slave.
2254
2255		- drivers/i2c/rcar_i2c.c:
2256		  - activate this driver with CONFIG_SYS_I2C_RCAR
2257		  - This driver adds 4 i2c buses
2258
2259		  - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2260		  - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2261		  - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2262		  - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2263		  - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2264		  - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2265		  - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2266		  - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2267		  - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2268
2269		- drivers/i2c/sh_i2c.c:
2270		  - activate this driver with CONFIG_SYS_I2C_SH
2271		  - This driver adds from 2 to 5 i2c buses
2272
2273		  - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2274		  - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2275		  - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2276		  - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2277		  - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2278		  - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2279		  - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2280		  - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2281		  - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2282		  - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2283		  - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2284
2285		- drivers/i2c/omap24xx_i2c.c
2286		  - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2287		  - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2288		  - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2289		  - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2290		  - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2291		  - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2292		  - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2293		  - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2294		  - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2295		  - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2296		  - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2297
2298		- drivers/i2c/zynq_i2c.c
2299		  - activate this driver with CONFIG_SYS_I2C_ZYNQ
2300		  - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2301		  - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2302
2303		- drivers/i2c/s3c24x0_i2c.c:
2304		  - activate this driver with CONFIG_SYS_I2C_S3C24X0
2305		  - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2306		    9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2307		    with a fix speed from 100000 and the slave addr 0!
2308
2309		- drivers/i2c/ihs_i2c.c
2310		  - activate this driver with CONFIG_SYS_I2C_IHS
2311		  - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2312		  - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2313		  - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2314		  - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2315		  - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2316		  - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2317		  - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2318		  - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2319		  - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2320		  - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2321		  - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2322		  - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2323		  - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2324		  - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2325		  - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2326		  - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2327		  - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2328		  - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2329		  - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2330		  - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2331		  - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2332
2333		additional defines:
2334
2335		CONFIG_SYS_NUM_I2C_BUSES
2336		Hold the number of i2c buses you want to use. If you
2337		don't use/have i2c muxes on your i2c bus, this
2338		is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2339		omit this define.
2340
2341		CONFIG_SYS_I2C_DIRECT_BUS
2342		define this, if you don't use i2c muxes on your hardware.
2343		if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2344		omit this define.
2345
2346		CONFIG_SYS_I2C_MAX_HOPS
2347		define how many muxes are maximal consecutively connected
2348		on one i2c bus. If you not use i2c muxes, omit this
2349		define.
2350
2351		CONFIG_SYS_I2C_BUSES
2352		hold a list of buses you want to use, only used if
2353		CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2354		a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2355		CONFIG_SYS_NUM_I2C_BUSES = 9:
2356
2357		 CONFIG_SYS_I2C_BUSES	{{0, {I2C_NULL_HOP}}, \
2358					{0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2359					{0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2360					{0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2361					{0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2362					{0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2363					{1, {I2C_NULL_HOP}}, \
2364					{1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2365					{1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2366					}
2367
2368		which defines
2369			bus 0 on adapter 0 without a mux
2370			bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2371			bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2372			bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2373			bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2374			bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2375			bus 6 on adapter 1 without a mux
2376			bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2377			bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2378
2379		If you do not have i2c muxes on your board, omit this define.
2380
2381- Legacy I2C Support:	CONFIG_HARD_I2C
2382
2383		NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2384		provides the following compelling advantages:
2385
2386		- more than one i2c adapter is usable
2387		- approved multibus support
2388		- better i2c mux support
2389
2390		** Please consider updating your I2C driver now. **
2391
2392		These enable legacy I2C serial bus commands. Defining
2393		CONFIG_HARD_I2C will include the appropriate I2C driver
2394		for the selected CPU.
2395
2396		This will allow you to use i2c commands at the u-boot
2397		command line (as long as you set CONFIG_CMD_I2C in
2398		CONFIG_COMMANDS) and communicate with i2c based realtime
2399		clock chips. See common/cmd_i2c.c for a description of the
2400		command line interface.
2401
2402		CONFIG_HARD_I2C selects a hardware I2C controller.
2403
2404		There are several other quantities that must also be
2405		defined when you define CONFIG_HARD_I2C.
2406
2407		In both cases you will need to define CONFIG_SYS_I2C_SPEED
2408		to be the frequency (in Hz) at which you wish your i2c bus
2409		to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2410		the CPU's i2c node address).
2411
2412		Now, the u-boot i2c code for the mpc8xx
2413		(arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2414		and so its address should therefore be cleared to 0 (See,
2415		eg, MPC823e User's Manual p.16-473). So, set
2416		CONFIG_SYS_I2C_SLAVE to 0.
2417
2418		CONFIG_SYS_I2C_INIT_MPC5XXX
2419
2420		When a board is reset during an i2c bus transfer
2421		chips might think that the current transfer is still
2422		in progress.  Reset the slave devices by sending start
2423		commands until the slave device responds.
2424
2425		That's all that's required for CONFIG_HARD_I2C.
2426
2427		If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2428		then the following macros need to be defined (examples are
2429		from include/configs/lwmon.h):
2430
2431		I2C_INIT
2432
2433		(Optional). Any commands necessary to enable the I2C
2434		controller or configure ports.
2435
2436		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)
2437
2438		I2C_PORT
2439
2440		(Only for MPC8260 CPU). The I/O port to use (the code
2441		assumes both bits are on the same port). Valid values
2442		are 0..3 for ports A..D.
2443
2444		I2C_ACTIVE
2445
2446		The code necessary to make the I2C data line active
2447		(driven).  If the data line is open collector, this
2448		define can be null.
2449
2450		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
2451
2452		I2C_TRISTATE
2453
2454		The code necessary to make the I2C data line tri-stated
2455		(inactive).  If the data line is open collector, this
2456		define can be null.
2457
2458		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2459
2460		I2C_READ
2461
2462		Code that returns true if the I2C data line is high,
2463		false if it is low.
2464
2465		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2466
2467		I2C_SDA(bit)
2468
2469		If <bit> is true, sets the I2C data line high. If it
2470		is false, it clears it (low).
2471
2472		eg: #define I2C_SDA(bit) \
2473			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
2474			else	immr->im_cpm.cp_pbdat &= ~PB_SDA
2475
2476		I2C_SCL(bit)
2477
2478		If <bit> is true, sets the I2C clock line high. If it
2479		is false, it clears it (low).
2480
2481		eg: #define I2C_SCL(bit) \
2482			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
2483			else	immr->im_cpm.cp_pbdat &= ~PB_SCL
2484
2485		I2C_DELAY
2486
2487		This delay is invoked four times per clock cycle so this
2488		controls the rate of data transfer.  The data rate thus
2489		is 1 / (I2C_DELAY * 4). Often defined to be something
2490		like:
2491
2492		#define I2C_DELAY  udelay(2)
2493
2494		CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2495
2496		If your arch supports the generic GPIO framework (asm/gpio.h),
2497		then you may alternatively define the two GPIOs that are to be
2498		used as SCL / SDA.  Any of the previous I2C_xxx macros will
2499		have GPIO-based defaults assigned to them as appropriate.
2500
2501		You should define these to the GPIO value as given directly to
2502		the generic GPIO functions.
2503
2504		CONFIG_SYS_I2C_INIT_BOARD
2505
2506		When a board is reset during an i2c bus transfer
2507		chips might think that the current transfer is still
2508		in progress. On some boards it is possible to access
2509		the i2c SCLK line directly, either by using the
2510		processor pin as a GPIO or by having a second pin
2511		connected to the bus. If this option is defined a
2512		custom i2c_init_board() routine in boards/xxx/board.c
2513		is run early in the boot sequence.
2514
2515		CONFIG_SYS_I2C_BOARD_LATE_INIT
2516
2517		An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2518		defined a custom i2c_board_late_init() routine in
2519		boards/xxx/board.c is run AFTER the operations in i2c_init()
2520		is completed. This callpoint can be used to unreset i2c bus
2521		using CPU i2c controller register accesses for CPUs whose i2c
2522		controller provide such a method. It is called at the end of
2523		i2c_init() to allow i2c_init operations to setup the i2c bus
2524		controller on the CPU (e.g. setting bus speed & slave address).
2525
2526		CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2527
2528		This option enables configuration of bi_iic_fast[] flags
2529		in u-boot bd_info structure based on u-boot environment
2530		variable "i2cfast". (see also i2cfast)
2531
2532		CONFIG_I2C_MULTI_BUS
2533
2534		This option allows the use of multiple I2C buses, each of which
2535		must have a controller.	 At any point in time, only one bus is
2536		active.	 To switch to a different bus, use the 'i2c dev' command.
2537		Note that bus numbering is zero-based.
2538
2539		CONFIG_SYS_I2C_NOPROBES
2540
2541		This option specifies a list of I2C devices that will be skipped
2542		when the 'i2c probe' command is issued.	 If CONFIG_I2C_MULTI_BUS
2543		is set, specify a list of bus-device pairs.  Otherwise, specify
2544		a 1D array of device addresses
2545
2546		e.g.
2547			#undef	CONFIG_I2C_MULTI_BUS
2548			#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2549
2550		will skip addresses 0x50 and 0x68 on a board with one I2C bus
2551
2552			#define CONFIG_I2C_MULTI_BUS
2553			#define CONFIG_SYS_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
2554
2555		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2556
2557		CONFIG_SYS_SPD_BUS_NUM
2558
2559		If defined, then this indicates the I2C bus number for DDR SPD.
2560		If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2561
2562		CONFIG_SYS_RTC_BUS_NUM
2563
2564		If defined, then this indicates the I2C bus number for the RTC.
2565		If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2566
2567		CONFIG_SYS_DTT_BUS_NUM
2568
2569		If defined, then this indicates the I2C bus number for the DTT.
2570		If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2571
2572		CONFIG_SYS_I2C_DTT_ADDR:
2573
2574		If defined, specifies the I2C address of the DTT device.
2575		If not defined, then U-Boot uses predefined value for
2576		specified DTT device.
2577
2578		CONFIG_SOFT_I2C_READ_REPEATED_START
2579
2580		defining this will force the i2c_read() function in
2581		the soft_i2c driver to perform an I2C repeated start
2582		between writing the address pointer and reading the
2583		data.  If this define is omitted the default behaviour
2584		of doing a stop-start sequence will be used.  Most I2C
2585		devices can use either method, but some require one or
2586		the other.
2587
2588- SPI Support:	CONFIG_SPI
2589
2590		Enables SPI driver (so far only tested with
2591		SPI EEPROM, also an instance works with Crystal A/D and
2592		D/As on the SACSng board)
2593
2594		CONFIG_SH_SPI
2595
2596		Enables the driver for SPI controller on SuperH. Currently
2597		only SH7757 is supported.
2598
2599		CONFIG_SOFT_SPI
2600
2601		Enables a software (bit-bang) SPI driver rather than
2602		using hardware support. This is a general purpose
2603		driver that only requires three general I/O port pins
2604		(two outputs, one input) to function. If this is
2605		defined, the board configuration must define several
2606		SPI configuration items (port pins to use, etc). For
2607		an example, see include/configs/sacsng.h.
2608
2609		CONFIG_HARD_SPI
2610
2611		Enables a hardware SPI driver for general-purpose reads
2612		and writes.  As with CONFIG_SOFT_SPI, the board configuration
2613		must define a list of chip-select function pointers.
2614		Currently supported on some MPC8xxx processors.	 For an
2615		example, see include/configs/mpc8349emds.h.
2616
2617		CONFIG_MXC_SPI
2618
2619		Enables the driver for the SPI controllers on i.MX and MXC
2620		SoCs. Currently i.MX31/35/51 are supported.
2621
2622		CONFIG_SYS_SPI_MXC_WAIT
2623		Timeout for waiting until spi transfer completed.
2624		default: (CONFIG_SYS_HZ/100)     /* 10 ms */
2625
2626- FPGA Support: CONFIG_FPGA
2627
2628		Enables FPGA subsystem.
2629
2630		CONFIG_FPGA_<vendor>
2631
2632		Enables support for specific chip vendors.
2633		(ALTERA, XILINX)
2634
2635		CONFIG_FPGA_<family>
2636
2637		Enables support for FPGA family.
2638		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2639
2640		CONFIG_FPGA_COUNT
2641
2642		Specify the number of FPGA devices to support.
2643
2644		CONFIG_CMD_FPGA_LOADMK
2645
2646		Enable support for fpga loadmk command
2647
2648		CONFIG_CMD_FPGA_LOADP
2649
2650		Enable support for fpga loadp command - load partial bitstream
2651
2652		CONFIG_CMD_FPGA_LOADBP
2653
2654		Enable support for fpga loadbp command - load partial bitstream
2655		(Xilinx only)
2656
2657		CONFIG_SYS_FPGA_PROG_FEEDBACK
2658
2659		Enable printing of hash marks during FPGA configuration.
2660
2661		CONFIG_SYS_FPGA_CHECK_BUSY
2662
2663		Enable checks on FPGA configuration interface busy
2664		status by the configuration function. This option
2665		will require a board or device specific function to
2666		be written.
2667
2668		CONFIG_FPGA_DELAY
2669
2670		If defined, a function that provides delays in the FPGA
2671		configuration driver.
2672
2673		CONFIG_SYS_FPGA_CHECK_CTRLC
2674		Allow Control-C to interrupt FPGA configuration
2675
2676		CONFIG_SYS_FPGA_CHECK_ERROR
2677
2678		Check for configuration errors during FPGA bitfile
2679		loading. For example, abort during Virtex II
2680		configuration if the INIT_B line goes low (which
2681		indicated a CRC error).
2682
2683		CONFIG_SYS_FPGA_WAIT_INIT
2684
2685		Maximum time to wait for the INIT_B line to de-assert
2686		after PROB_B has been de-asserted during a Virtex II
2687		FPGA configuration sequence. The default time is 500
2688		ms.
2689
2690		CONFIG_SYS_FPGA_WAIT_BUSY
2691
2692		Maximum time to wait for BUSY to de-assert during
2693		Virtex II FPGA configuration. The default is 5 ms.
2694
2695		CONFIG_SYS_FPGA_WAIT_CONFIG
2696
2697		Time to wait after FPGA configuration. The default is
2698		200 ms.
2699
2700- Configuration Management:
2701		CONFIG_BUILD_TARGET
2702
2703		Some SoCs need special image types (e.g. U-Boot binary
2704		with a special header) as build targets. By defining
2705		CONFIG_BUILD_TARGET in the SoC / board header, this
2706		special image will be automatically built upon calling
2707		make / buildman.
2708
2709		CONFIG_IDENT_STRING
2710
2711		If defined, this string will be added to the U-Boot
2712		version information (U_BOOT_VERSION)
2713
2714- Vendor Parameter Protection:
2715
2716		U-Boot considers the values of the environment
2717		variables "serial#" (Board Serial Number) and
2718		"ethaddr" (Ethernet Address) to be parameters that
2719		are set once by the board vendor / manufacturer, and
2720		protects these variables from casual modification by
2721		the user. Once set, these variables are read-only,
2722		and write or delete attempts are rejected. You can
2723		change this behaviour:
2724
2725		If CONFIG_ENV_OVERWRITE is #defined in your config
2726		file, the write protection for vendor parameters is
2727		completely disabled. Anybody can change or delete
2728		these parameters.
2729
2730		Alternatively, if you define _both_ an ethaddr in the
2731		default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2732		Ethernet address is installed in the environment,
2733		which can be changed exactly ONCE by the user. [The
2734		serial# is unaffected by this, i. e. it remains
2735		read-only.]
2736
2737		The same can be accomplished in a more flexible way
2738		for any variable by configuring the type of access
2739		to allow for those variables in the ".flags" variable
2740		or define CONFIG_ENV_FLAGS_LIST_STATIC.
2741
2742- Protected RAM:
2743		CONFIG_PRAM
2744
2745		Define this variable to enable the reservation of
2746		"protected RAM", i. e. RAM which is not overwritten
2747		by U-Boot. Define CONFIG_PRAM to hold the number of
2748		kB you want to reserve for pRAM. You can overwrite
2749		this default value by defining an environment
2750		variable "pram" to the number of kB you want to
2751		reserve. Note that the board info structure will
2752		still show the full amount of RAM. If pRAM is
2753		reserved, a new environment variable "mem" will
2754		automatically be defined to hold the amount of
2755		remaining RAM in a form that can be passed as boot
2756		argument to Linux, for instance like that:
2757
2758			setenv bootargs ... mem=\${mem}
2759			saveenv
2760
2761		This way you can tell Linux not to use this memory,
2762		either, which results in a memory region that will
2763		not be affected by reboots.
2764
2765		*WARNING* If your board configuration uses automatic
2766		detection of the RAM size, you must make sure that
2767		this memory test is non-destructive. So far, the
2768		following board configurations are known to be
2769		"pRAM-clean":
2770
2771			IVMS8, IVML24, SPD8xx, TQM8xxL,
2772			HERMES, IP860, RPXlite, LWMON,
2773			FLAGADM, TQM8260
2774
2775- Access to physical memory region (> 4GB)
2776		Some basic support is provided for operations on memory not
2777		normally accessible to U-Boot - e.g. some architectures
2778		support access to more than 4GB of memory on 32-bit
2779		machines using physical address extension or similar.
2780		Define CONFIG_PHYSMEM to access this basic support, which
2781		currently only supports clearing the memory.
2782
2783- Error Recovery:
2784		CONFIG_PANIC_HANG
2785
2786		Define this variable to stop the system in case of a
2787		fatal error, so that you have to reset it manually.
2788		This is probably NOT a good idea for an embedded
2789		system where you want the system to reboot
2790		automatically as fast as possible, but it may be
2791		useful during development since you can try to debug
2792		the conditions that lead to the situation.
2793
2794		CONFIG_NET_RETRY_COUNT
2795
2796		This variable defines the number of retries for
2797		network operations like ARP, RARP, TFTP, or BOOTP
2798		before giving up the operation. If not defined, a
2799		default value of 5 is used.
2800
2801		CONFIG_ARP_TIMEOUT
2802
2803		Timeout waiting for an ARP reply in milliseconds.
2804
2805		CONFIG_NFS_TIMEOUT
2806
2807		Timeout in milliseconds used in NFS protocol.
2808		If you encounter "ERROR: Cannot umount" in nfs command,
2809		try longer timeout such as
2810		#define CONFIG_NFS_TIMEOUT 10000UL
2811
2812- Command Interpreter:
2813		CONFIG_AUTO_COMPLETE
2814
2815		Enable auto completion of commands using TAB.
2816
2817		CONFIG_SYS_PROMPT_HUSH_PS2
2818
2819		This defines the secondary prompt string, which is
2820		printed when the command interpreter needs more input
2821		to complete a command. Usually "> ".
2822
2823	Note:
2824
2825		In the current implementation, the local variables
2826		space and global environment variables space are
2827		separated. Local variables are those you define by
2828		simply typing `name=value'. To access a local
2829		variable later on, you have write `$name' or
2830		`${name}'; to execute the contents of a variable
2831		directly type `$name' at the command prompt.
2832
2833		Global environment variables are those you use
2834		setenv/printenv to work with. To run a command stored
2835		in such a variable, you need to use the run command,
2836		and you must not use the '$' sign to access them.
2837
2838		To store commands and special characters in a
2839		variable, please use double quotation marks
2840		surrounding the whole text of the variable, instead
2841		of the backslashes before semicolons and special
2842		symbols.
2843
2844- Command Line Editing and History:
2845		CONFIG_CMDLINE_EDITING
2846
2847		Enable editing and History functions for interactive
2848		command line input operations
2849
2850- Command Line PS1/PS2 support:
2851		CONFIG_CMDLINE_PS_SUPPORT
2852
2853		Enable support for changing the command prompt string
2854		at run-time. Only static string is supported so far.
2855		The string is obtained from environment variables PS1
2856		and PS2.
2857
2858- Default Environment:
2859		CONFIG_EXTRA_ENV_SETTINGS
2860
2861		Define this to contain any number of null terminated
2862		strings (variable = value pairs) that will be part of
2863		the default environment compiled into the boot image.
2864
2865		For example, place something like this in your
2866		board's config file:
2867
2868		#define CONFIG_EXTRA_ENV_SETTINGS \
2869			"myvar1=value1\0" \
2870			"myvar2=value2\0"
2871
2872		Warning: This method is based on knowledge about the
2873		internal format how the environment is stored by the
2874		U-Boot code. This is NOT an official, exported
2875		interface! Although it is unlikely that this format
2876		will change soon, there is no guarantee either.
2877		You better know what you are doing here.
2878
2879		Note: overly (ab)use of the default environment is
2880		discouraged. Make sure to check other ways to preset
2881		the environment like the "source" command or the
2882		boot command first.
2883
2884		CONFIG_ENV_VARS_UBOOT_CONFIG
2885
2886		Define this in order to add variables describing the
2887		U-Boot build configuration to the default environment.
2888		These will be named arch, cpu, board, vendor, and soc.
2889
2890		Enabling this option will cause the following to be defined:
2891
2892		- CONFIG_SYS_ARCH
2893		- CONFIG_SYS_CPU
2894		- CONFIG_SYS_BOARD
2895		- CONFIG_SYS_VENDOR
2896		- CONFIG_SYS_SOC
2897
2898		CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2899
2900		Define this in order to add variables describing certain
2901		run-time determined information about the hardware to the
2902		environment.  These will be named board_name, board_rev.
2903
2904		CONFIG_DELAY_ENVIRONMENT
2905
2906		Normally the environment is loaded when the board is
2907		initialised so that it is available to U-Boot. This inhibits
2908		that so that the environment is not available until
2909		explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2910		this is instead controlled by the value of
2911		/config/load-environment.
2912
2913- Parallel Flash support:
2914		CONFIG_SYS_NO_FLASH
2915
2916		Traditionally U-Boot was run on systems with parallel NOR
2917		flash. This option is used to disable support for parallel NOR
2918		flash. This option should be defined if the board does not have
2919		parallel flash.
2920
2921		If this option is not defined one of the generic flash drivers
2922		(e.g.  CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
2923		selected or the board must provide an implementation of the
2924		flash API (see include/flash.h).
2925
2926- DataFlash Support:
2927		CONFIG_HAS_DATAFLASH
2928
2929		Defining this option enables DataFlash features and
2930		allows to read/write in Dataflash via the standard
2931		commands cp, md...
2932
2933- Serial Flash support
2934		CONFIG_CMD_SF
2935
2936		Defining this option enables SPI flash commands
2937		'sf probe/read/write/erase/update'.
2938
2939		Usage requires an initial 'probe' to define the serial
2940		flash parameters, followed by read/write/erase/update
2941		commands.
2942
2943		The following defaults may be provided by the platform
2944		to handle the common case when only a single serial
2945		flash is present on the system.
2946
2947		CONFIG_SF_DEFAULT_BUS		Bus identifier
2948		CONFIG_SF_DEFAULT_CS		Chip-select
2949		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
2950		CONFIG_SF_DEFAULT_SPEED		in Hz
2951
2952		CONFIG_CMD_SF_TEST
2953
2954		Define this option to include a destructive SPI flash
2955		test ('sf test').
2956
2957		CONFIG_SF_DUAL_FLASH		Dual flash memories
2958
2959		Define this option to use dual flash support where two flash
2960		memories can be connected with a given cs line.
2961		Currently Xilinx Zynq qspi supports these type of connections.
2962
2963- SystemACE Support:
2964		CONFIG_SYSTEMACE
2965
2966		Adding this option adds support for Xilinx SystemACE
2967		chips attached via some sort of local bus. The address
2968		of the chip must also be defined in the
2969		CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2970
2971		#define CONFIG_SYSTEMACE
2972		#define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2973
2974		When SystemACE support is added, the "ace" device type
2975		becomes available to the fat commands, i.e. fatls.
2976
2977- TFTP Fixed UDP Port:
2978		CONFIG_TFTP_PORT
2979
2980		If this is defined, the environment variable tftpsrcp
2981		is used to supply the TFTP UDP source port value.
2982		If tftpsrcp isn't defined, the normal pseudo-random port
2983		number generator is used.
2984
2985		Also, the environment variable tftpdstp is used to supply
2986		the TFTP UDP destination port value.  If tftpdstp isn't
2987		defined, the normal port 69 is used.
2988
2989		The purpose for tftpsrcp is to allow a TFTP server to
2990		blindly start the TFTP transfer using the pre-configured
2991		target IP address and UDP port. This has the effect of
2992		"punching through" the (Windows XP) firewall, allowing
2993		the remainder of the TFTP transfer to proceed normally.
2994		A better solution is to properly configure the firewall,
2995		but sometimes that is not allowed.
2996
2997- Hashing support:
2998		CONFIG_CMD_HASH
2999
3000		This enables a generic 'hash' command which can produce
3001		hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3002
3003		CONFIG_HASH_VERIFY
3004
3005		Enable the hash verify command (hash -v). This adds to code
3006		size a little.
3007
3008		CONFIG_SHA1 - This option enables support of hashing using SHA1
3009		algorithm. The hash is calculated in software.
3010		CONFIG_SHA256 - This option enables support of hashing using
3011		SHA256 algorithm. The hash is calculated in software.
3012		CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3013		for SHA1/SHA256 hashing.
3014		This affects the 'hash' command and also the
3015		hash_lookup_algo() function.
3016		CONFIG_SHA_PROG_HW_ACCEL - This option enables
3017		hardware-acceleration for SHA1/SHA256 progressive hashing.
3018		Data can be streamed in a block at a time and the hashing
3019		is performed in hardware.
3020
3021		Note: There is also a sha1sum command, which should perhaps
3022		be deprecated in favour of 'hash sha1'.
3023
3024- Freescale i.MX specific commands:
3025		CONFIG_CMD_HDMIDETECT
3026		This enables 'hdmidet' command which returns true if an
3027		HDMI monitor is detected.  This command is i.MX 6 specific.
3028
3029		CONFIG_CMD_BMODE
3030		This enables the 'bmode' (bootmode) command for forcing
3031		a boot from specific media.
3032
3033		This is useful for forcing the ROM's usb downloader to
3034		activate upon a watchdog reset which is nice when iterating
3035		on U-Boot.  Using the reset button or running bmode normal
3036		will set it back to normal.  This command currently
3037		supports i.MX53 and i.MX6.
3038
3039- bootcount support:
3040		CONFIG_BOOTCOUNT_LIMIT
3041
3042		This enables the bootcounter support, see:
3043		http://www.denx.de/wiki/DULG/UBootBootCountLimit
3044
3045		CONFIG_AT91SAM9XE
3046		enable special bootcounter support on at91sam9xe based boards.
3047		CONFIG_BLACKFIN
3048		enable special bootcounter support on blackfin based boards.
3049		CONFIG_SOC_DA8XX
3050		enable special bootcounter support on da850 based boards.
3051		CONFIG_BOOTCOUNT_RAM
3052		enable support for the bootcounter in RAM
3053		CONFIG_BOOTCOUNT_I2C
3054		enable support for the bootcounter on an i2c (like RTC) device.
3055			CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3056			CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3057						    the bootcounter.
3058			CONFIG_BOOTCOUNT_ALEN = address len
3059
3060- Show boot progress:
3061		CONFIG_SHOW_BOOT_PROGRESS
3062
3063		Defining this option allows to add some board-
3064		specific code (calling a user-provided function
3065		"show_boot_progress(int)") that enables you to show
3066		the system's boot progress on some display (for
3067		example, some LED's) on your board. At the moment,
3068		the following checkpoints are implemented:
3069
3070
3071Legacy uImage format:
3072
3073  Arg	Where			When
3074    1	common/cmd_bootm.c	before attempting to boot an image
3075   -1	common/cmd_bootm.c	Image header has bad	 magic number
3076    2	common/cmd_bootm.c	Image header has correct magic number
3077   -2	common/cmd_bootm.c	Image header has bad	 checksum
3078    3	common/cmd_bootm.c	Image header has correct checksum
3079   -3	common/cmd_bootm.c	Image data   has bad	 checksum
3080    4	common/cmd_bootm.c	Image data   has correct checksum
3081   -4	common/cmd_bootm.c	Image is for unsupported architecture
3082    5	common/cmd_bootm.c	Architecture check OK
3083   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
3084    6	common/cmd_bootm.c	Image Type check OK
3085   -6	common/cmd_bootm.c	gunzip uncompression error
3086   -7	common/cmd_bootm.c	Unimplemented compression type
3087    7	common/cmd_bootm.c	Uncompression OK
3088    8	common/cmd_bootm.c	No uncompress/copy overwrite error
3089   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
3090
3091    9	common/image.c		Start initial ramdisk verification
3092  -10	common/image.c		Ramdisk header has bad	   magic number
3093  -11	common/image.c		Ramdisk header has bad	   checksum
3094   10	common/image.c		Ramdisk header is OK
3095  -12	common/image.c		Ramdisk data   has bad	   checksum
3096   11	common/image.c		Ramdisk data   has correct checksum
3097   12	common/image.c		Ramdisk verification complete, start loading
3098  -13	common/image.c		Wrong Image Type (not PPC Linux ramdisk)
3099   13	common/image.c		Start multifile image verification
3100   14	common/image.c		No initial ramdisk, no multifile, continue.
3101
3102   15	arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3103
3104  -30	arch/powerpc/lib/board.c	Fatal error, hang the system
3105  -31	post/post.c		POST test failed, detected by post_output_backlog()
3106  -32	post/post.c		POST test failed, detected by post_run_single()
3107
3108   34	common/cmd_doc.c	before loading a Image from a DOC device
3109  -35	common/cmd_doc.c	Bad usage of "doc" command
3110   35	common/cmd_doc.c	correct usage of "doc" command
3111  -36	common/cmd_doc.c	No boot device
3112   36	common/cmd_doc.c	correct boot device
3113  -37	common/cmd_doc.c	Unknown Chip ID on boot device
3114   37	common/cmd_doc.c	correct chip ID found, device available
3115  -38	common/cmd_doc.c	Read Error on boot device
3116   38	common/cmd_doc.c	reading Image header from DOC device OK
3117  -39	common/cmd_doc.c	Image header has bad magic number
3118   39	common/cmd_doc.c	Image header has correct magic number
3119  -40	common/cmd_doc.c	Error reading Image from DOC device
3120   40	common/cmd_doc.c	Image header has correct magic number
3121   41	common/cmd_ide.c	before loading a Image from a IDE device
3122  -42	common/cmd_ide.c	Bad usage of "ide" command
3123   42	common/cmd_ide.c	correct usage of "ide" command
3124  -43	common/cmd_ide.c	No boot device
3125   43	common/cmd_ide.c	boot device found
3126  -44	common/cmd_ide.c	Device not available
3127   44	common/cmd_ide.c	Device available
3128  -45	common/cmd_ide.c	wrong partition selected
3129   45	common/cmd_ide.c	partition selected
3130  -46	common/cmd_ide.c	Unknown partition table
3131   46	common/cmd_ide.c	valid partition table found
3132  -47	common/cmd_ide.c	Invalid partition type
3133   47	common/cmd_ide.c	correct partition type
3134  -48	common/cmd_ide.c	Error reading Image Header on boot device
3135   48	common/cmd_ide.c	reading Image Header from IDE device OK
3136  -49	common/cmd_ide.c	Image header has bad magic number
3137   49	common/cmd_ide.c	Image header has correct magic number
3138  -50	common/cmd_ide.c	Image header has bad	 checksum
3139   50	common/cmd_ide.c	Image header has correct checksum
3140  -51	common/cmd_ide.c	Error reading Image from IDE device
3141   51	common/cmd_ide.c	reading Image from IDE device OK
3142   52	common/cmd_nand.c	before loading a Image from a NAND device
3143  -53	common/cmd_nand.c	Bad usage of "nand" command
3144   53	common/cmd_nand.c	correct usage of "nand" command
3145  -54	common/cmd_nand.c	No boot device
3146   54	common/cmd_nand.c	boot device found
3147  -55	common/cmd_nand.c	Unknown Chip ID on boot device
3148   55	common/cmd_nand.c	correct chip ID found, device available
3149  -56	common/cmd_nand.c	Error reading Image Header on boot device
3150   56	common/cmd_nand.c	reading Image Header from NAND device OK
3151  -57	common/cmd_nand.c	Image header has bad magic number
3152   57	common/cmd_nand.c	Image header has correct magic number
3153  -58	common/cmd_nand.c	Error reading Image from NAND device
3154   58	common/cmd_nand.c	reading Image from NAND device OK
3155
3156  -60	common/env_common.c	Environment has a bad CRC, using default
3157
3158   64	net/eth.c		starting with Ethernet configuration.
3159  -64	net/eth.c		no Ethernet found.
3160   65	net/eth.c		Ethernet found.
3161
3162  -80	common/cmd_net.c	usage wrong
3163   80	common/cmd_net.c	before calling net_loop()
3164  -81	common/cmd_net.c	some error in net_loop() occurred
3165   81	common/cmd_net.c	net_loop() back without error
3166  -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
3167   82	common/cmd_net.c	trying automatic boot
3168   83	common/cmd_net.c	running "source" command
3169  -83	common/cmd_net.c	some error in automatic boot or "source" command
3170   84	common/cmd_net.c	end without errors
3171
3172FIT uImage format:
3173
3174  Arg	Where			When
3175  100	common/cmd_bootm.c	Kernel FIT Image has correct format
3176 -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
3177  101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
3178 -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
3179  102	common/cmd_bootm.c	Kernel unit name specified
3180 -103	common/cmd_bootm.c	Can't get kernel subimage node offset
3181  103	common/cmd_bootm.c	Found configuration node
3182  104	common/cmd_bootm.c	Got kernel subimage node offset
3183 -104	common/cmd_bootm.c	Kernel subimage hash verification failed
3184  105	common/cmd_bootm.c	Kernel subimage hash verification OK
3185 -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
3186  106	common/cmd_bootm.c	Architecture check OK
3187 -106	common/cmd_bootm.c	Kernel subimage has wrong type
3188  107	common/cmd_bootm.c	Kernel subimage type OK
3189 -107	common/cmd_bootm.c	Can't get kernel subimage data/size
3190  108	common/cmd_bootm.c	Got kernel subimage data/size
3191 -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
3192 -109	common/cmd_bootm.c	Can't get kernel subimage type
3193 -110	common/cmd_bootm.c	Can't get kernel subimage comp
3194 -111	common/cmd_bootm.c	Can't get kernel subimage os
3195 -112	common/cmd_bootm.c	Can't get kernel subimage load address
3196 -113	common/cmd_bootm.c	Image uncompress/copy overwrite error
3197
3198  120	common/image.c		Start initial ramdisk verification
3199 -120	common/image.c		Ramdisk FIT image has incorrect format
3200  121	common/image.c		Ramdisk FIT image has correct format
3201  122	common/image.c		No ramdisk subimage unit name, using configuration
3202 -122	common/image.c		Can't get configuration for ramdisk subimage
3203  123	common/image.c		Ramdisk unit name specified
3204 -124	common/image.c		Can't get ramdisk subimage node offset
3205  125	common/image.c		Got ramdisk subimage node offset
3206 -125	common/image.c		Ramdisk subimage hash verification failed
3207  126	common/image.c		Ramdisk subimage hash verification OK
3208 -126	common/image.c		Ramdisk subimage for unsupported architecture
3209  127	common/image.c		Architecture check OK
3210 -127	common/image.c		Can't get ramdisk subimage data/size
3211  128	common/image.c		Got ramdisk subimage data/size
3212  129	common/image.c		Can't get ramdisk load address
3213 -129	common/image.c		Got ramdisk load address
3214
3215 -130	common/cmd_doc.c	Incorrect FIT image format
3216  131	common/cmd_doc.c	FIT image format OK
3217
3218 -140	common/cmd_ide.c	Incorrect FIT image format
3219  141	common/cmd_ide.c	FIT image format OK
3220
3221 -150	common/cmd_nand.c	Incorrect FIT image format
3222  151	common/cmd_nand.c	FIT image format OK
3223
3224- legacy image format:
3225		CONFIG_IMAGE_FORMAT_LEGACY
3226		enables the legacy image format support in U-Boot.
3227
3228		Default:
3229		enabled if CONFIG_FIT_SIGNATURE is not defined.
3230
3231		CONFIG_DISABLE_IMAGE_LEGACY
3232		disable the legacy image format
3233
3234		This define is introduced, as the legacy image format is
3235		enabled per default for backward compatibility.
3236
3237- FIT image support:
3238		CONFIG_FIT_DISABLE_SHA256
3239		Supporting SHA256 hashes has quite an impact on binary size.
3240		For constrained systems sha256 hash support can be disabled
3241		with this option.
3242
3243		TODO(sjg@chromium.org): Adjust this option to be positive,
3244		and move it to Kconfig
3245
3246- Standalone program support:
3247		CONFIG_STANDALONE_LOAD_ADDR
3248
3249		This option defines a board specific value for the
3250		address where standalone program gets loaded, thus
3251		overwriting the architecture dependent default
3252		settings.
3253
3254- Frame Buffer Address:
3255		CONFIG_FB_ADDR
3256
3257		Define CONFIG_FB_ADDR if you want to use specific
3258		address for frame buffer.  This is typically the case
3259		when using a graphics controller has separate video
3260		memory.  U-Boot will then place the frame buffer at
3261		the given address instead of dynamically reserving it
3262		in system RAM by calling lcd_setmem(), which grabs
3263		the memory for the frame buffer depending on the
3264		configured panel size.
3265
3266		Please see board_init_f function.
3267
3268- Automatic software updates via TFTP server
3269		CONFIG_UPDATE_TFTP
3270		CONFIG_UPDATE_TFTP_CNT_MAX
3271		CONFIG_UPDATE_TFTP_MSEC_MAX
3272
3273		These options enable and control the auto-update feature;
3274		for a more detailed description refer to doc/README.update.
3275
3276- MTD Support (mtdparts command, UBI support)
3277		CONFIG_MTD_DEVICE
3278
3279		Adds the MTD device infrastructure from the Linux kernel.
3280		Needed for mtdparts command support.
3281
3282		CONFIG_MTD_PARTITIONS
3283
3284		Adds the MTD partitioning infrastructure from the Linux
3285		kernel. Needed for UBI support.
3286
3287- UBI support
3288		CONFIG_CMD_UBI
3289
3290		Adds commands for interacting with MTD partitions formatted
3291		with the UBI flash translation layer
3292
3293		Requires also defining CONFIG_RBTREE
3294
3295		CONFIG_UBI_SILENCE_MSG
3296
3297		Make the verbose messages from UBI stop printing.  This leaves
3298		warnings and errors enabled.
3299
3300
3301		CONFIG_MTD_UBI_WL_THRESHOLD
3302		This parameter defines the maximum difference between the highest
3303		erase counter value and the lowest erase counter value of eraseblocks
3304		of UBI devices. When this threshold is exceeded, UBI starts performing
3305		wear leveling by means of moving data from eraseblock with low erase
3306		counter to eraseblocks with high erase counter.
3307
3308		The default value should be OK for SLC NAND flashes, NOR flashes and
3309		other flashes which have eraseblock life-cycle 100000 or more.
3310		However, in case of MLC NAND flashes which typically have eraseblock
3311		life-cycle less than 10000, the threshold should be lessened (e.g.,
3312		to 128 or 256, although it does not have to be power of 2).
3313
3314		default: 4096
3315
3316		CONFIG_MTD_UBI_BEB_LIMIT
3317		This option specifies the maximum bad physical eraseblocks UBI
3318		expects on the MTD device (per 1024 eraseblocks). If the
3319		underlying flash does not admit of bad eraseblocks (e.g. NOR
3320		flash), this value is ignored.
3321
3322		NAND datasheets often specify the minimum and maximum NVM
3323		(Number of Valid Blocks) for the flashes' endurance lifetime.
3324		The maximum expected bad eraseblocks per 1024 eraseblocks
3325		then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3326		which gives 20 for most NANDs (MaxNVB is basically the total
3327		count of eraseblocks on the chip).
3328
3329		To put it differently, if this value is 20, UBI will try to
3330		reserve about 1.9% of physical eraseblocks for bad blocks
3331		handling. And that will be 1.9% of eraseblocks on the entire
3332		NAND chip, not just the MTD partition UBI attaches. This means
3333		that if you have, say, a NAND flash chip admits maximum 40 bad
3334		eraseblocks, and it is split on two MTD partitions of the same
3335		size, UBI will reserve 40 eraseblocks when attaching a
3336		partition.
3337
3338		default: 20
3339
3340		CONFIG_MTD_UBI_FASTMAP
3341		Fastmap is a mechanism which allows attaching an UBI device
3342		in nearly constant time. Instead of scanning the whole MTD device it
3343		only has to locate a checkpoint (called fastmap) on the device.
3344		The on-flash fastmap contains all information needed to attach
3345		the device. Using fastmap makes only sense on large devices where
3346		attaching by scanning takes long. UBI will not automatically install
3347		a fastmap on old images, but you can set the UBI parameter
3348		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3349		that fastmap-enabled images are still usable with UBI implementations
3350		without	fastmap support. On typical flash devices the whole fastmap
3351		fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3352
3353		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3354		Set this parameter to enable fastmap automatically on images
3355		without a fastmap.
3356		default: 0
3357
3358		CONFIG_MTD_UBI_FM_DEBUG
3359		Enable UBI fastmap debug
3360		default: 0
3361
3362- UBIFS support
3363		CONFIG_CMD_UBIFS
3364
3365		Adds commands for interacting with UBI volumes formatted as
3366		UBIFS.  UBIFS is read-only in u-boot.
3367
3368		Requires UBI support as well as CONFIG_LZO
3369
3370		CONFIG_UBIFS_SILENCE_MSG
3371
3372		Make the verbose messages from UBIFS stop printing.  This leaves
3373		warnings and errors enabled.
3374
3375- SPL framework
3376		CONFIG_SPL
3377		Enable building of SPL globally.
3378
3379		CONFIG_SPL_LDSCRIPT
3380		LDSCRIPT for linking the SPL binary.
3381
3382		CONFIG_SPL_MAX_FOOTPRINT
3383		Maximum size in memory allocated to the SPL, BSS included.
3384		When defined, the linker checks that the actual memory
3385		used by SPL from _start to __bss_end does not exceed it.
3386		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3387		must not be both defined at the same time.
3388
3389		CONFIG_SPL_MAX_SIZE
3390		Maximum size of the SPL image (text, data, rodata, and
3391		linker lists sections), BSS excluded.
3392		When defined, the linker checks that the actual size does
3393		not exceed it.
3394
3395		CONFIG_SPL_TEXT_BASE
3396		TEXT_BASE for linking the SPL binary.
3397
3398		CONFIG_SPL_RELOC_TEXT_BASE
3399		Address to relocate to.  If unspecified, this is equal to
3400		CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3401
3402		CONFIG_SPL_BSS_START_ADDR
3403		Link address for the BSS within the SPL binary.
3404
3405		CONFIG_SPL_BSS_MAX_SIZE
3406		Maximum size in memory allocated to the SPL BSS.
3407		When defined, the linker checks that the actual memory used
3408		by SPL from __bss_start to __bss_end does not exceed it.
3409		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3410		must not be both defined at the same time.
3411
3412		CONFIG_SPL_STACK
3413		Adress of the start of the stack SPL will use
3414
3415		CONFIG_SPL_PANIC_ON_RAW_IMAGE
3416		When defined, SPL will panic() if the image it has
3417		loaded does not have a signature.
3418		Defining this is useful when code which loads images
3419		in SPL cannot guarantee that absolutely all read errors
3420		will be caught.
3421		An example is the LPC32XX MLC NAND driver, which will
3422		consider that a completely unreadable NAND block is bad,
3423		and thus should be skipped silently.
3424
3425		CONFIG_SPL_ABORT_ON_RAW_IMAGE
3426		When defined, SPL will proceed to another boot method
3427		if the image it has loaded does not have a signature.
3428
3429		CONFIG_SPL_RELOC_STACK
3430		Adress of the start of the stack SPL will use after
3431		relocation.  If unspecified, this is equal to
3432		CONFIG_SPL_STACK.
3433
3434		CONFIG_SYS_SPL_MALLOC_START
3435		Starting address of the malloc pool used in SPL.
3436		When this option is set the full malloc is used in SPL and
3437		it is set up by spl_init() and before that, the simple malloc()
3438		can be used if CONFIG_SYS_MALLOC_F is defined.
3439
3440		CONFIG_SYS_SPL_MALLOC_SIZE
3441		The size of the malloc pool used in SPL.
3442
3443		CONFIG_SPL_FRAMEWORK
3444		Enable the SPL framework under common/.  This framework
3445		supports MMC, NAND and YMODEM loading of U-Boot and NAND
3446		NAND loading of the Linux Kernel.
3447
3448		CONFIG_SPL_OS_BOOT
3449		Enable booting directly to an OS from SPL.
3450		See also: doc/README.falcon
3451
3452		CONFIG_SPL_DISPLAY_PRINT
3453		For ARM, enable an optional function to print more information
3454		about the running system.
3455
3456		CONFIG_SPL_INIT_MINIMAL
3457		Arch init code should be built for a very small image
3458
3459		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3460		CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3461		Address and partition on the MMC to load U-Boot from
3462		when the MMC is being used in raw mode.
3463
3464		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3465		Partition on the MMC to load U-Boot from when the MMC is being
3466		used in raw mode
3467
3468		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3469		Sector to load kernel uImage from when MMC is being
3470		used in raw mode (for Falcon mode)
3471
3472		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3473		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3474		Sector and number of sectors to load kernel argument
3475		parameters from when MMC is being used in raw mode
3476		(for falcon mode)
3477
3478		CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3479		Partition on the MMC to load U-Boot from when the MMC is being
3480		used in fs mode
3481
3482		CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3483		Filename to read to load U-Boot when reading from filesystem
3484
3485		CONFIG_SPL_FS_LOAD_KERNEL_NAME
3486		Filename to read to load kernel uImage when reading
3487		from filesystem (for Falcon mode)
3488
3489		CONFIG_SPL_FS_LOAD_ARGS_NAME
3490		Filename to read to load kernel argument parameters
3491		when reading from filesystem (for Falcon mode)
3492
3493		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3494		Set this for NAND SPL on PPC mpc83xx targets, so that
3495		start.S waits for the rest of the SPL to load before
3496		continuing (the hardware starts execution after just
3497		loading the first page rather than the full 4K).
3498
3499		CONFIG_SPL_SKIP_RELOCATE
3500		Avoid SPL relocation
3501
3502		CONFIG_SPL_NAND_BASE
3503		Include nand_base.c in the SPL.  Requires
3504		CONFIG_SPL_NAND_DRIVERS.
3505
3506		CONFIG_SPL_NAND_DRIVERS
3507		SPL uses normal NAND drivers, not minimal drivers.
3508
3509		CONFIG_SPL_NAND_ECC
3510		Include standard software ECC in the SPL
3511
3512		CONFIG_SPL_NAND_SIMPLE
3513		Support for NAND boot using simple NAND drivers that
3514		expose the cmd_ctrl() interface.
3515
3516		CONFIG_SPL_UBI
3517		Support for a lightweight UBI (fastmap) scanner and
3518		loader
3519
3520		CONFIG_SPL_NAND_RAW_ONLY
3521		Support to boot only raw u-boot.bin images. Use this only
3522		if you need to save space.
3523
3524		CONFIG_SPL_COMMON_INIT_DDR
3525		Set for common ddr init with serial presence detect in
3526		SPL binary.
3527
3528		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3529		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3530		CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3531		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3532		CONFIG_SYS_NAND_ECCBYTES
3533		Defines the size and behavior of the NAND that SPL uses
3534		to read U-Boot
3535
3536		CONFIG_SPL_NAND_BOOT
3537		Add support NAND boot
3538
3539		CONFIG_SYS_NAND_U_BOOT_OFFS
3540		Location in NAND to read U-Boot from
3541
3542		CONFIG_SYS_NAND_U_BOOT_DST
3543		Location in memory to load U-Boot to
3544
3545		CONFIG_SYS_NAND_U_BOOT_SIZE
3546		Size of image to load
3547
3548		CONFIG_SYS_NAND_U_BOOT_START
3549		Entry point in loaded image to jump to
3550
3551		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3552		Define this if you need to first read the OOB and then the
3553		data. This is used, for example, on davinci platforms.
3554
3555		CONFIG_SPL_OMAP3_ID_NAND
3556		Support for an OMAP3-specific set of functions to return the
3557		ID and MFR of the first attached NAND chip, if present.
3558
3559		CONFIG_SPL_RAM_DEVICE
3560		Support for running image already present in ram, in SPL binary
3561
3562		CONFIG_SPL_PAD_TO
3563		Image offset to which the SPL should be padded before appending
3564		the SPL payload. By default, this is defined as
3565		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3566		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3567		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3568
3569		CONFIG_SPL_TARGET
3570		Final target image containing SPL and payload.  Some SPLs
3571		use an arch-specific makefile fragment instead, for
3572		example if more than one image needs to be produced.
3573
3574		CONFIG_FIT_SPL_PRINT
3575		Printing information about a FIT image adds quite a bit of
3576		code to SPL. So this is normally disabled in SPL. Use this
3577		option to re-enable it. This will affect the output of the
3578		bootm command when booting a FIT image.
3579
3580- TPL framework
3581		CONFIG_TPL
3582		Enable building of TPL globally.
3583
3584		CONFIG_TPL_PAD_TO
3585		Image offset to which the TPL should be padded before appending
3586		the TPL payload. By default, this is defined as
3587		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3588		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3589		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3590
3591- Interrupt support (PPC):
3592
3593		There are common interrupt_init() and timer_interrupt()
3594		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3595		for CPU specific initialization. interrupt_init_cpu()
3596		should set decrementer_count to appropriate value. If
3597		CPU resets decrementer automatically after interrupt
3598		(ppc4xx) it should set decrementer_count to zero.
3599		timer_interrupt() calls timer_interrupt_cpu() for CPU
3600		specific handling. If board has watchdog / status_led
3601		/ other_activity_monitor it works automatically from
3602		general timer_interrupt().
3603
3604
3605Board initialization settings:
3606------------------------------
3607
3608During Initialization u-boot calls a number of board specific functions
3609to allow the preparation of board specific prerequisites, e.g. pin setup
3610before drivers are initialized. To enable these callbacks the
3611following configuration macros have to be defined. Currently this is
3612architecture specific, so please check arch/your_architecture/lib/board.c
3613typically in board_init_f() and board_init_r().
3614
3615- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3616- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3617- CONFIG_BOARD_LATE_INIT: Call board_late_init()
3618- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3619
3620Configuration Settings:
3621-----------------------
3622
3623- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3624		Optionally it can be defined to support 64-bit memory commands.
3625
3626- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3627		undefine this when you're short of memory.
3628
3629- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3630		width of the commands listed in the 'help' command output.
3631
3632- CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
3633		prompt for user input.
3634
3635- CONFIG_SYS_CBSIZE:	Buffer size for input from the Console
3636
3637- CONFIG_SYS_PBSIZE:	Buffer size for Console output
3638
3639- CONFIG_SYS_MAXARGS:	max. Number of arguments accepted for monitor commands
3640
3641- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3642		the application (usually a Linux kernel) when it is
3643		booted
3644
3645- CONFIG_SYS_BAUDRATE_TABLE:
3646		List of legal baudrate settings for this board.
3647
3648- CONFIG_SYS_CONSOLE_INFO_QUIET
3649		Suppress display of console information at boot.
3650
3651- CONFIG_SYS_CONSOLE_IS_IN_ENV
3652		If the board specific function
3653			extern int overwrite_console (void);
3654		returns 1, the stdin, stderr and stdout are switched to the
3655		serial port, else the settings in the environment are used.
3656
3657- CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3658		Enable the call to overwrite_console().
3659
3660- CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3661		Enable overwrite of previous console environment settings.
3662
3663- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3664		Begin and End addresses of the area used by the
3665		simple memory test.
3666
3667- CONFIG_SYS_ALT_MEMTEST:
3668		Enable an alternate, more extensive memory test.
3669
3670- CONFIG_SYS_MEMTEST_SCRATCH:
3671		Scratch address used by the alternate memory test
3672		You only need to set this if address zero isn't writeable
3673
3674- CONFIG_SYS_MEM_RESERVE_SECURE
3675		Only implemented for ARMv8 for now.
3676		If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3677		is substracted from total RAM and won't be reported to OS.
3678		This memory can be used as secure memory. A variable
3679		gd->arch.secure_ram is used to track the location. In systems
3680		the RAM base is not zero, or RAM is divided into banks,
3681		this variable needs to be recalcuated to get the address.
3682
3683- CONFIG_SYS_MEM_TOP_HIDE:
3684		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3685		this specified memory area will get subtracted from the top
3686		(end) of RAM and won't get "touched" at all by U-Boot. By
3687		fixing up gd->ram_size the Linux kernel should gets passed
3688		the now "corrected" memory size and won't touch it either.
3689		This should work for arch/ppc and arch/powerpc. Only Linux
3690		board ports in arch/powerpc with bootwrapper support that
3691		recalculate the memory size from the SDRAM controller setup
3692		will have to get fixed in Linux additionally.
3693
3694		This option can be used as a workaround for the 440EPx/GRx
3695		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3696		be touched.
3697
3698		WARNING: Please make sure that this value is a multiple of
3699		the Linux page size (normally 4k). If this is not the case,
3700		then the end address of the Linux memory will be located at a
3701		non page size aligned address and this could cause major
3702		problems.
3703
3704- CONFIG_SYS_LOADS_BAUD_CHANGE:
3705		Enable temporary baudrate change while serial download
3706
3707- CONFIG_SYS_SDRAM_BASE:
3708		Physical start address of SDRAM. _Must_ be 0 here.
3709
3710- CONFIG_SYS_FLASH_BASE:
3711		Physical start address of Flash memory.
3712
3713- CONFIG_SYS_MONITOR_BASE:
3714		Physical start address of boot monitor code (set by
3715		make config files to be same as the text base address
3716		(CONFIG_SYS_TEXT_BASE) used when linking) - same as
3717		CONFIG_SYS_FLASH_BASE when booting from flash.
3718
3719- CONFIG_SYS_MONITOR_LEN:
3720		Size of memory reserved for monitor code, used to
3721		determine _at_compile_time_ (!) if the environment is
3722		embedded within the U-Boot image, or in a separate
3723		flash sector.
3724
3725- CONFIG_SYS_MALLOC_LEN:
3726		Size of DRAM reserved for malloc() use.
3727
3728- CONFIG_SYS_MALLOC_F_LEN
3729		Size of the malloc() pool for use before relocation. If
3730		this is defined, then a very simple malloc() implementation
3731		will become available before relocation. The address is just
3732		below the global data, and the stack is moved down to make
3733		space.
3734
3735		This feature allocates regions with increasing addresses
3736		within the region. calloc() is supported, but realloc()
3737		is not available. free() is supported but does nothing.
3738		The memory will be freed (or in fact just forgotten) when
3739		U-Boot relocates itself.
3740
3741- CONFIG_SYS_MALLOC_SIMPLE
3742		Provides a simple and small malloc() and calloc() for those
3743		boards which do not use the full malloc in SPL (which is
3744		enabled with CONFIG_SYS_SPL_MALLOC_START).
3745
3746- CONFIG_SYS_NONCACHED_MEMORY:
3747		Size of non-cached memory area. This area of memory will be
3748		typically located right below the malloc() area and mapped
3749		uncached in the MMU. This is useful for drivers that would
3750		otherwise require a lot of explicit cache maintenance. For
3751		some drivers it's also impossible to properly maintain the
3752		cache. For example if the regions that need to be flushed
3753		are not a multiple of the cache-line size, *and* padding
3754		cannot be allocated between the regions to align them (i.e.
3755		if the HW requires a contiguous array of regions, and the
3756		size of each region is not cache-aligned), then a flush of
3757		one region may result in overwriting data that hardware has
3758		written to another region in the same cache-line. This can
3759		happen for example in network drivers where descriptors for
3760		buffers are typically smaller than the CPU cache-line (e.g.
3761		16 bytes vs. 32 or 64 bytes).
3762
3763		Non-cached memory is only supported on 32-bit ARM at present.
3764
3765- CONFIG_SYS_BOOTM_LEN:
3766		Normally compressed uImages are limited to an
3767		uncompressed size of 8 MBytes. If this is not enough,
3768		you can define CONFIG_SYS_BOOTM_LEN in your board config file
3769		to adjust this setting to your needs.
3770
3771- CONFIG_SYS_BOOTMAPSZ:
3772		Maximum size of memory mapped by the startup code of
3773		the Linux kernel; all data that must be processed by
3774		the Linux kernel (bd_info, boot arguments, FDT blob if
3775		used) must be put below this limit, unless "bootm_low"
3776		environment variable is defined and non-zero. In such case
3777		all data for the Linux kernel must be between "bootm_low"
3778		and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.	 The environment
3779		variable "bootm_mapsize" will override the value of
3780		CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
3781		then the value in "bootm_size" will be used instead.
3782
3783- CONFIG_SYS_BOOT_RAMDISK_HIGH:
3784		Enable initrd_high functionality.  If defined then the
3785		initrd_high feature is enabled and the bootm ramdisk subcommand
3786		is enabled.
3787
3788- CONFIG_SYS_BOOT_GET_CMDLINE:
3789		Enables allocating and saving kernel cmdline in space between
3790		"bootm_low" and "bootm_low" + BOOTMAPSZ.
3791
3792- CONFIG_SYS_BOOT_GET_KBD:
3793		Enables allocating and saving a kernel copy of the bd_info in
3794		space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3795
3796- CONFIG_SYS_MAX_FLASH_BANKS:
3797		Max number of Flash memory banks
3798
3799- CONFIG_SYS_MAX_FLASH_SECT:
3800		Max number of sectors on a Flash chip
3801
3802- CONFIG_SYS_FLASH_ERASE_TOUT:
3803		Timeout for Flash erase operations (in ms)
3804
3805- CONFIG_SYS_FLASH_WRITE_TOUT:
3806		Timeout for Flash write operations (in ms)
3807
3808- CONFIG_SYS_FLASH_LOCK_TOUT
3809		Timeout for Flash set sector lock bit operation (in ms)
3810
3811- CONFIG_SYS_FLASH_UNLOCK_TOUT
3812		Timeout for Flash clear lock bits operation (in ms)
3813
3814- CONFIG_SYS_FLASH_PROTECTION
3815		If defined, hardware flash sectors protection is used
3816		instead of U-Boot software protection.
3817
3818- CONFIG_SYS_DIRECT_FLASH_TFTP:
3819
3820		Enable TFTP transfers directly to flash memory;
3821		without this option such a download has to be
3822		performed in two steps: (1) download to RAM, and (2)
3823		copy from RAM to flash.
3824
3825		The two-step approach is usually more reliable, since
3826		you can check if the download worked before you erase
3827		the flash, but in some situations (when system RAM is
3828		too limited to allow for a temporary copy of the
3829		downloaded image) this option may be very useful.
3830
3831- CONFIG_SYS_FLASH_CFI:
3832		Define if the flash driver uses extra elements in the
3833		common flash structure for storing flash geometry.
3834
3835- CONFIG_FLASH_CFI_DRIVER
3836		This option also enables the building of the cfi_flash driver
3837		in the drivers directory
3838
3839- CONFIG_FLASH_CFI_MTD
3840		This option enables the building of the cfi_mtd driver
3841		in the drivers directory. The driver exports CFI flash
3842		to the MTD layer.
3843
3844- CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3845		Use buffered writes to flash.
3846
3847- CONFIG_FLASH_SPANSION_S29WS_N
3848		s29ws-n MirrorBit flash has non-standard addresses for buffered
3849		write commands.
3850
3851- CONFIG_SYS_FLASH_QUIET_TEST
3852		If this option is defined, the common CFI flash doesn't
3853		print it's warning upon not recognized FLASH banks. This
3854		is useful, if some of the configured banks are only
3855		optionally available.
3856
3857- CONFIG_FLASH_SHOW_PROGRESS
3858		If defined (must be an integer), print out countdown
3859		digits and dots.  Recommended value: 45 (9..1) for 80
3860		column displays, 15 (3..1) for 40 column displays.
3861
3862- CONFIG_FLASH_VERIFY
3863		If defined, the content of the flash (destination) is compared
3864		against the source after the write operation. An error message
3865		will be printed when the contents are not identical.
3866		Please note that this option is useless in nearly all cases,
3867		since such flash programming errors usually are detected earlier
3868		while unprotecting/erasing/programming. Please only enable
3869		this option if you really know what you are doing.
3870
3871- CONFIG_SYS_RX_ETH_BUFFER:
3872		Defines the number of Ethernet receive buffers. On some
3873		Ethernet controllers it is recommended to set this value
3874		to 8 or even higher (EEPRO100 or 405 EMAC), since all
3875		buffers can be full shortly after enabling the interface
3876		on high Ethernet traffic.
3877		Defaults to 4 if not defined.
3878
3879- CONFIG_ENV_MAX_ENTRIES
3880
3881	Maximum number of entries in the hash table that is used
3882	internally to store the environment settings. The default
3883	setting is supposed to be generous and should work in most
3884	cases. This setting can be used to tune behaviour; see
3885	lib/hashtable.c for details.
3886
3887- CONFIG_ENV_FLAGS_LIST_DEFAULT
3888- CONFIG_ENV_FLAGS_LIST_STATIC
3889	Enable validation of the values given to environment variables when
3890	calling env set.  Variables can be restricted to only decimal,
3891	hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
3892	the variables can also be restricted to IP address or MAC address.
3893
3894	The format of the list is:
3895		type_attribute = [s|d|x|b|i|m]
3896		access_attribute = [a|r|o|c]
3897		attributes = type_attribute[access_attribute]
3898		entry = variable_name[:attributes]
3899		list = entry[,list]
3900
3901	The type attributes are:
3902		s - String (default)
3903		d - Decimal
3904		x - Hexadecimal
3905		b - Boolean ([1yYtT|0nNfF])
3906		i - IP address
3907		m - MAC address
3908
3909	The access attributes are:
3910		a - Any (default)
3911		r - Read-only
3912		o - Write-once
3913		c - Change-default
3914
3915	- CONFIG_ENV_FLAGS_LIST_DEFAULT
3916		Define this to a list (string) to define the ".flags"
3917		environment variable in the default or embedded environment.
3918
3919	- CONFIG_ENV_FLAGS_LIST_STATIC
3920		Define this to a list (string) to define validation that
3921		should be done if an entry is not found in the ".flags"
3922		environment variable.  To override a setting in the static
3923		list, simply add an entry for the same variable name to the
3924		".flags" variable.
3925
3926	If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3927	regular expression. This allows multiple variables to define the same
3928	flags without explicitly listing them for each variable.
3929
3930- CONFIG_ENV_ACCESS_IGNORE_FORCE
3931	If defined, don't allow the -f switch to env set override variable
3932	access flags.
3933
3934- CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3935	This is set by OMAP boards for the max time that reset should
3936	be asserted. See doc/README.omap-reset-time for details on how
3937	the value can be calculated on a given board.
3938
3939- CONFIG_USE_STDINT
3940	If stdint.h is available with your toolchain you can define this
3941	option to enable it. You can provide option 'USE_STDINT=1' when
3942	building U-Boot to enable this.
3943
3944The following definitions that deal with the placement and management
3945of environment data (variable area); in general, we support the
3946following configurations:
3947
3948- CONFIG_BUILD_ENVCRC:
3949
3950	Builds up envcrc with the target environment so that external utils
3951	may easily extract it and embed it in final U-Boot images.
3952
3953- CONFIG_ENV_IS_IN_FLASH:
3954
3955	Define this if the environment is in flash memory.
3956
3957	a) The environment occupies one whole flash sector, which is
3958	   "embedded" in the text segment with the U-Boot code. This
3959	   happens usually with "bottom boot sector" or "top boot
3960	   sector" type flash chips, which have several smaller
3961	   sectors at the start or the end. For instance, such a
3962	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3963	   such a case you would place the environment in one of the
3964	   4 kB sectors - with U-Boot code before and after it. With
3965	   "top boot sector" type flash chips, you would put the
3966	   environment in one of the last sectors, leaving a gap
3967	   between U-Boot and the environment.
3968
3969	- CONFIG_ENV_OFFSET:
3970
3971	   Offset of environment data (variable area) to the
3972	   beginning of flash memory; for instance, with bottom boot
3973	   type flash chips the second sector can be used: the offset
3974	   for this sector is given here.
3975
3976	   CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3977
3978	- CONFIG_ENV_ADDR:
3979
3980	   This is just another way to specify the start address of
3981	   the flash sector containing the environment (instead of
3982	   CONFIG_ENV_OFFSET).
3983
3984	- CONFIG_ENV_SECT_SIZE:
3985
3986	   Size of the sector containing the environment.
3987
3988
3989	b) Sometimes flash chips have few, equal sized, BIG sectors.
3990	   In such a case you don't want to spend a whole sector for
3991	   the environment.
3992
3993	- CONFIG_ENV_SIZE:
3994
3995	   If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3996	   and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3997	   of this flash sector for the environment. This saves
3998	   memory for the RAM copy of the environment.
3999
4000	   It may also save flash memory if you decide to use this
4001	   when your environment is "embedded" within U-Boot code,
4002	   since then the remainder of the flash sector could be used
4003	   for U-Boot code. It should be pointed out that this is
4004	   STRONGLY DISCOURAGED from a robustness point of view:
4005	   updating the environment in flash makes it always
4006	   necessary to erase the WHOLE sector. If something goes
4007	   wrong before the contents has been restored from a copy in
4008	   RAM, your target system will be dead.
4009
4010	- CONFIG_ENV_ADDR_REDUND
4011	  CONFIG_ENV_SIZE_REDUND
4012
4013	   These settings describe a second storage area used to hold
4014	   a redundant copy of the environment data, so that there is
4015	   a valid backup copy in case there is a power failure during
4016	   a "saveenv" operation.
4017
4018BE CAREFUL! Any changes to the flash layout, and some changes to the
4019source code will make it necessary to adapt <board>/u-boot.lds*
4020accordingly!
4021
4022
4023- CONFIG_ENV_IS_IN_NVRAM:
4024
4025	Define this if you have some non-volatile memory device
4026	(NVRAM, battery buffered SRAM) which you want to use for the
4027	environment.
4028
4029	- CONFIG_ENV_ADDR:
4030	- CONFIG_ENV_SIZE:
4031
4032	  These two #defines are used to determine the memory area you
4033	  want to use for environment. It is assumed that this memory
4034	  can just be read and written to, without any special
4035	  provision.
4036
4037BE CAREFUL! The first access to the environment happens quite early
4038in U-Boot initialization (when we try to get the setting of for the
4039console baudrate). You *MUST* have mapped your NVRAM area then, or
4040U-Boot will hang.
4041
4042Please note that even with NVRAM we still use a copy of the
4043environment in RAM: we could work on NVRAM directly, but we want to
4044keep settings there always unmodified except somebody uses "saveenv"
4045to save the current settings.
4046
4047
4048- CONFIG_ENV_IS_IN_EEPROM:
4049
4050	Use this if you have an EEPROM or similar serial access
4051	device and a driver for it.
4052
4053	- CONFIG_ENV_OFFSET:
4054	- CONFIG_ENV_SIZE:
4055
4056	  These two #defines specify the offset and size of the
4057	  environment area within the total memory of your EEPROM.
4058
4059	- CONFIG_SYS_I2C_EEPROM_ADDR:
4060	  If defined, specified the chip address of the EEPROM device.
4061	  The default address is zero.
4062
4063	- CONFIG_SYS_I2C_EEPROM_BUS:
4064	  If defined, specified the i2c bus of the EEPROM device.
4065
4066	- CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4067	  If defined, the number of bits used to address bytes in a
4068	  single page in the EEPROM device.  A 64 byte page, for example
4069	  would require six bits.
4070
4071	- CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4072	  If defined, the number of milliseconds to delay between
4073	  page writes.	The default is zero milliseconds.
4074
4075	- CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4076	  The length in bytes of the EEPROM memory array address.  Note
4077	  that this is NOT the chip address length!
4078
4079	- CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4080	  EEPROM chips that implement "address overflow" are ones
4081	  like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4082	  address and the extra bits end up in the "chip address" bit
4083	  slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4084	  byte chips.
4085
4086	  Note that we consider the length of the address field to
4087	  still be one byte because the extra address bits are hidden
4088	  in the chip address.
4089
4090	- CONFIG_SYS_EEPROM_SIZE:
4091	  The size in bytes of the EEPROM device.
4092
4093	- CONFIG_ENV_EEPROM_IS_ON_I2C
4094	  define this, if you have I2C and SPI activated, and your
4095	  EEPROM, which holds the environment, is on the I2C bus.
4096
4097	- CONFIG_I2C_ENV_EEPROM_BUS
4098	  if you have an Environment on an EEPROM reached over
4099	  I2C muxes, you can define here, how to reach this
4100	  EEPROM. For example:
4101
4102	  #define CONFIG_I2C_ENV_EEPROM_BUS	  1
4103
4104	  EEPROM which holds the environment, is reached over
4105	  a pca9547 i2c mux with address 0x70, channel 3.
4106
4107- CONFIG_ENV_IS_IN_DATAFLASH:
4108
4109	Define this if you have a DataFlash memory device which you
4110	want to use for the environment.
4111
4112	- CONFIG_ENV_OFFSET:
4113	- CONFIG_ENV_ADDR:
4114	- CONFIG_ENV_SIZE:
4115
4116	  These three #defines specify the offset and size of the
4117	  environment area within the total memory of your DataFlash placed
4118	  at the specified address.
4119
4120- CONFIG_ENV_IS_IN_SPI_FLASH:
4121
4122	Define this if you have a SPI Flash memory device which you
4123	want to use for the environment.
4124
4125	- CONFIG_ENV_OFFSET:
4126	- CONFIG_ENV_SIZE:
4127
4128	  These two #defines specify the offset and size of the
4129	  environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4130	  aligned to an erase sector boundary.
4131
4132	- CONFIG_ENV_SECT_SIZE:
4133
4134	  Define the SPI flash's sector size.
4135
4136	- CONFIG_ENV_OFFSET_REDUND (optional):
4137
4138	  This setting describes a second storage area of CONFIG_ENV_SIZE
4139	  size used to hold a redundant copy of the environment data, so
4140	  that there is a valid backup copy in case there is a power failure
4141	  during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
4142	  aligned to an erase sector boundary.
4143
4144	- CONFIG_ENV_SPI_BUS (optional):
4145	- CONFIG_ENV_SPI_CS (optional):
4146
4147	  Define the SPI bus and chip select. If not defined they will be 0.
4148
4149	- CONFIG_ENV_SPI_MAX_HZ (optional):
4150
4151	  Define the SPI max work clock. If not defined then use 1MHz.
4152
4153	- CONFIG_ENV_SPI_MODE (optional):
4154
4155	  Define the SPI work mode. If not defined then use SPI_MODE_3.
4156
4157- CONFIG_ENV_IS_IN_REMOTE:
4158
4159	Define this if you have a remote memory space which you
4160	want to use for the local device's environment.
4161
4162	- CONFIG_ENV_ADDR:
4163	- CONFIG_ENV_SIZE:
4164
4165	  These two #defines specify the address and size of the
4166	  environment area within the remote memory space. The
4167	  local device can get the environment from remote memory
4168	  space by SRIO or PCIE links.
4169
4170BE CAREFUL! For some special cases, the local device can not use
4171"saveenv" command. For example, the local device will get the
4172environment stored in a remote NOR flash by SRIO or PCIE link,
4173but it can not erase, write this NOR flash by SRIO or PCIE interface.
4174
4175- CONFIG_ENV_IS_IN_NAND:
4176
4177	Define this if you have a NAND device which you want to use
4178	for the environment.
4179
4180	- CONFIG_ENV_OFFSET:
4181	- CONFIG_ENV_SIZE:
4182
4183	  These two #defines specify the offset and size of the environment
4184	  area within the first NAND device.  CONFIG_ENV_OFFSET must be
4185	  aligned to an erase block boundary.
4186
4187	- CONFIG_ENV_OFFSET_REDUND (optional):
4188
4189	  This setting describes a second storage area of CONFIG_ENV_SIZE
4190	  size used to hold a redundant copy of the environment data, so
4191	  that there is a valid backup copy in case there is a power failure
4192	  during a "saveenv" operation.	 CONFIG_ENV_OFFSET_REDUND must be
4193	  aligned to an erase block boundary.
4194
4195	- CONFIG_ENV_RANGE (optional):
4196
4197	  Specifies the length of the region in which the environment
4198	  can be written.  This should be a multiple of the NAND device's
4199	  block size.  Specifying a range with more erase blocks than
4200	  are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4201	  the range to be avoided.
4202
4203	- CONFIG_ENV_OFFSET_OOB (optional):
4204
4205	  Enables support for dynamically retrieving the offset of the
4206	  environment from block zero's out-of-band data.  The
4207	  "nand env.oob" command can be used to record this offset.
4208	  Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4209	  using CONFIG_ENV_OFFSET_OOB.
4210
4211- CONFIG_NAND_ENV_DST
4212
4213	Defines address in RAM to which the nand_spl code should copy the
4214	environment. If redundant environment is used, it will be copied to
4215	CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4216
4217- CONFIG_ENV_IS_IN_UBI:
4218
4219	Define this if you have an UBI volume that you want to use for the
4220	environment.  This has the benefit of wear-leveling the environment
4221	accesses, which is important on NAND.
4222
4223	- CONFIG_ENV_UBI_PART:
4224
4225	  Define this to a string that is the mtd partition containing the UBI.
4226
4227	- CONFIG_ENV_UBI_VOLUME:
4228
4229	  Define this to the name of the volume that you want to store the
4230	  environment in.
4231
4232	- CONFIG_ENV_UBI_VOLUME_REDUND:
4233
4234	  Define this to the name of another volume to store a second copy of
4235	  the environment in.  This will enable redundant environments in UBI.
4236	  It is assumed that both volumes are in the same MTD partition.
4237
4238	- CONFIG_UBI_SILENCE_MSG
4239	- CONFIG_UBIFS_SILENCE_MSG
4240
4241	  You will probably want to define these to avoid a really noisy system
4242	  when storing the env in UBI.
4243
4244- CONFIG_ENV_IS_IN_FAT:
4245       Define this if you want to use the FAT file system for the environment.
4246
4247       - FAT_ENV_INTERFACE:
4248
4249         Define this to a string that is the name of the block device.
4250
4251       - FAT_ENV_DEV_AND_PART:
4252
4253         Define this to a string to specify the partition of the device. It can
4254         be as following:
4255
4256           "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4257               - "D:P": device D partition P. Error occurs if device D has no
4258                        partition table.
4259               - "D:0": device D.
4260               - "D" or "D:": device D partition 1 if device D has partition
4261                              table, or the whole device D if has no partition
4262                              table.
4263               - "D:auto": first partition in device D with bootable flag set.
4264                           If none, first valid partition in device D. If no
4265                           partition table then means device D.
4266
4267       - FAT_ENV_FILE:
4268
4269         It's a string of the FAT file name. This file use to store the
4270         environment.
4271
4272       - CONFIG_FAT_WRITE:
4273         This should be defined. Otherwise it cannot save the environment file.
4274
4275- CONFIG_ENV_IS_IN_MMC:
4276
4277	Define this if you have an MMC device which you want to use for the
4278	environment.
4279
4280	- CONFIG_SYS_MMC_ENV_DEV:
4281
4282	  Specifies which MMC device the environment is stored in.
4283
4284	- CONFIG_SYS_MMC_ENV_PART (optional):
4285
4286	  Specifies which MMC partition the environment is stored in. If not
4287	  set, defaults to partition 0, the user area. Common values might be
4288	  1 (first MMC boot partition), 2 (second MMC boot partition).
4289
4290	- CONFIG_ENV_OFFSET:
4291	- CONFIG_ENV_SIZE:
4292
4293	  These two #defines specify the offset and size of the environment
4294	  area within the specified MMC device.
4295
4296	  If offset is positive (the usual case), it is treated as relative to
4297	  the start of the MMC partition. If offset is negative, it is treated
4298	  as relative to the end of the MMC partition. This can be useful if
4299	  your board may be fitted with different MMC devices, which have
4300	  different sizes for the MMC partitions, and you always want the
4301	  environment placed at the very end of the partition, to leave the
4302	  maximum possible space before it, to store other data.
4303
4304	  These two values are in units of bytes, but must be aligned to an
4305	  MMC sector boundary.
4306
4307	- CONFIG_ENV_OFFSET_REDUND (optional):
4308
4309	  Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4310	  hold a redundant copy of the environment data. This provides a
4311	  valid backup copy in case the other copy is corrupted, e.g. due
4312	  to a power failure during a "saveenv" operation.
4313
4314	  This value may also be positive or negative; this is handled in the
4315	  same way as CONFIG_ENV_OFFSET.
4316
4317	  This value is also in units of bytes, but must also be aligned to
4318	  an MMC sector boundary.
4319
4320	- CONFIG_ENV_SIZE_REDUND (optional):
4321
4322	  This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4323	  set. If this value is set, it must be set to the same value as
4324	  CONFIG_ENV_SIZE.
4325
4326- CONFIG_SYS_SPI_INIT_OFFSET
4327
4328	Defines offset to the initial SPI buffer area in DPRAM. The
4329	area is used at an early stage (ROM part) if the environment
4330	is configured to reside in the SPI EEPROM: We need a 520 byte
4331	scratch DPRAM area. It is used between the two initialization
4332	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4333	to be a good choice since it makes it far enough from the
4334	start of the data area as well as from the stack pointer.
4335
4336Please note that the environment is read-only until the monitor
4337has been relocated to RAM and a RAM copy of the environment has been
4338created; also, when using EEPROM you will have to use getenv_f()
4339until then to read environment variables.
4340
4341The environment is protected by a CRC32 checksum. Before the monitor
4342is relocated into RAM, as a result of a bad CRC you will be working
4343with the compiled-in default environment - *silently*!!! [This is
4344necessary, because the first environment variable we need is the
4345"baudrate" setting for the console - if we have a bad CRC, we don't
4346have any device yet where we could complain.]
4347
4348Note: once the monitor has been relocated, then it will complain if
4349the default environment is used; a new CRC is computed as soon as you
4350use the "saveenv" command to store a valid environment.
4351
4352- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4353		Echo the inverted Ethernet link state to the fault LED.
4354
4355		Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4356		      also needs to be defined.
4357
4358- CONFIG_SYS_FAULT_MII_ADDR:
4359		MII address of the PHY to check for the Ethernet link state.
4360
4361- CONFIG_NS16550_MIN_FUNCTIONS:
4362		Define this if you desire to only have use of the NS16550_init
4363		and NS16550_putc functions for the serial driver located at
4364		drivers/serial/ns16550.c.  This option is useful for saving
4365		space for already greatly restricted images, including but not
4366		limited to NAND_SPL configurations.
4367
4368- CONFIG_DISPLAY_BOARDINFO
4369		Display information about the board that U-Boot is running on
4370		when U-Boot starts up. The board function checkboard() is called
4371		to do this.
4372
4373- CONFIG_DISPLAY_BOARDINFO_LATE
4374		Similar to the previous option, but display this information
4375		later, once stdio is running and output goes to the LCD, if
4376		present.
4377
4378- CONFIG_BOARD_SIZE_LIMIT:
4379		Maximum size of the U-Boot image. When defined, the
4380		build system checks that the actual size does not
4381		exceed it.
4382
4383Low Level (hardware related) configuration options:
4384---------------------------------------------------
4385
4386- CONFIG_SYS_CACHELINE_SIZE:
4387		Cache Line Size of the CPU.
4388
4389- CONFIG_SYS_DEFAULT_IMMR:
4390		Default address of the IMMR after system reset.
4391
4392		Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4393		and RPXsuper) to be able to adjust the position of
4394		the IMMR register after a reset.
4395
4396- CONFIG_SYS_CCSRBAR_DEFAULT:
4397		Default (power-on reset) physical address of CCSR on Freescale
4398		PowerPC SOCs.
4399
4400- CONFIG_SYS_CCSRBAR:
4401		Virtual address of CCSR.  On a 32-bit build, this is typically
4402		the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4403
4404		CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4405		for cross-platform code that uses that macro instead.
4406
4407- CONFIG_SYS_CCSRBAR_PHYS:
4408		Physical address of CCSR.  CCSR can be relocated to a new
4409		physical address, if desired.  In this case, this macro should
4410		be set to that address.	 Otherwise, it should be set to the
4411		same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
4412		is typically relocated on 36-bit builds.  It is recommended
4413		that this macro be defined via the _HIGH and _LOW macros:
4414
4415		#define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4416			* 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4417
4418- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4419		Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS.	This value is typically
4420		either 0 (32-bit build) or 0xF (36-bit build).	This macro is
4421		used in assembly code, so it must not contain typecasts or
4422		integer size suffixes (e.g. "ULL").
4423
4424- CONFIG_SYS_CCSRBAR_PHYS_LOW:
4425		Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS.  This macro is
4426		used in assembly code, so it must not contain typecasts or
4427		integer size suffixes (e.g. "ULL").
4428
4429- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4430		If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4431		forced to a value that ensures that CCSR is not relocated.
4432
4433- Floppy Disk Support:
4434		CONFIG_SYS_FDC_DRIVE_NUMBER
4435
4436		the default drive number (default value 0)
4437
4438		CONFIG_SYS_ISA_IO_STRIDE
4439
4440		defines the spacing between FDC chipset registers
4441		(default value 1)
4442
4443		CONFIG_SYS_ISA_IO_OFFSET
4444
4445		defines the offset of register from address. It
4446		depends on which part of the data bus is connected to
4447		the FDC chipset. (default value 0)
4448
4449		If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4450		CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4451		default value.
4452
4453		if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4454		fdc_hw_init() is called at the beginning of the FDC
4455		setup. fdc_hw_init() must be provided by the board
4456		source code. It is used to make hardware-dependent
4457		initializations.
4458
4459- CONFIG_IDE_AHB:
4460		Most IDE controllers were designed to be connected with PCI
4461		interface. Only few of them were designed for AHB interface.
4462		When software is doing ATA command and data transfer to
4463		IDE devices through IDE-AHB controller, some additional
4464		registers accessing to these kind of IDE-AHB controller
4465		is required.
4466
4467- CONFIG_SYS_IMMR:	Physical address of the Internal Memory.
4468		DO NOT CHANGE unless you know exactly what you're
4469		doing! (11-4) [MPC8xx/82xx systems only]
4470
4471- CONFIG_SYS_INIT_RAM_ADDR:
4472
4473		Start address of memory area that can be used for
4474		initial data and stack; please note that this must be
4475		writable memory that is working WITHOUT special
4476		initialization, i. e. you CANNOT use normal RAM which
4477		will become available only after programming the
4478		memory controller and running certain initialization
4479		sequences.
4480
4481		U-Boot uses the following memory types:
4482		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4483		- MPC824X: data cache
4484		- PPC4xx:  data cache
4485
4486- CONFIG_SYS_GBL_DATA_OFFSET:
4487
4488		Offset of the initial data structure in the memory
4489		area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4490		CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4491		data is located at the end of the available space
4492		(sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4493		CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4494		below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4495		CONFIG_SYS_GBL_DATA_OFFSET) downward.
4496
4497	Note:
4498		On the MPC824X (or other systems that use the data
4499		cache for initial memory) the address chosen for
4500		CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4501		point to an otherwise UNUSED address space between
4502		the top of RAM and the start of the PCI space.
4503
4504- CONFIG_SYS_SIUMCR:	SIU Module Configuration (11-6)
4505
4506- CONFIG_SYS_SYPCR:	System Protection Control (11-9)
4507
4508- CONFIG_SYS_TBSCR:	Time Base Status and Control (11-26)
4509
4510- CONFIG_SYS_PISCR:	Periodic Interrupt Status and Control (11-31)
4511
4512- CONFIG_SYS_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
4513
4514- CONFIG_SYS_SCCR:	System Clock and reset Control Register (15-27)
4515
4516- CONFIG_SYS_OR_TIMING_SDRAM:
4517		SDRAM timing
4518
4519- CONFIG_SYS_MAMR_PTA:
4520		periodic timer for refresh
4521
4522- CONFIG_SYS_DER:	Debug Event Register (37-47)
4523
4524- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4525  CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4526  CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4527  CONFIG_SYS_BR1_PRELIM:
4528		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4529
4530- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4531  CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4532  CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4533		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4534
4535- CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4536  CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4537		Machine Mode Register and Memory Periodic Timer
4538		Prescaler definitions (SDRAM timing)
4539
4540- CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4541		enable I2C microcode relocation patch (MPC8xx);
4542		define relocation offset in DPRAM [DSP2]
4543
4544- CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4545		enable SMC microcode relocation patch (MPC8xx);
4546		define relocation offset in DPRAM [SMC1]
4547
4548- CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4549		enable SPI microcode relocation patch (MPC8xx);
4550		define relocation offset in DPRAM [SCC4]
4551
4552- CONFIG_SYS_USE_OSCCLK:
4553		Use OSCM clock mode on MBX8xx board. Be careful,
4554		wrong setting might damage your board. Read
4555		doc/README.MBX before setting this variable!
4556
4557- CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4558		Offset of the bootmode word in DPRAM used by post
4559		(Power On Self Tests). This definition overrides
4560		#define'd default value in commproc.h resp.
4561		cpm_8260.h.
4562
4563- CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4564  CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4565  CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4566  CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4567  CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4568  CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4569  CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4570  CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4571		Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4572
4573- CONFIG_PCI_DISABLE_PCIE:
4574		Disable PCI-Express on systems where it is supported but not
4575		required.
4576
4577- CONFIG_PCI_ENUM_ONLY
4578		Only scan through and get the devices on the buses.
4579		Don't do any setup work, presumably because someone or
4580		something has already done it, and we don't need to do it
4581		a second time.	Useful for platforms that are pre-booted
4582		by coreboot or similar.
4583
4584- CONFIG_PCI_INDIRECT_BRIDGE:
4585		Enable support for indirect PCI bridges.
4586
4587- CONFIG_SYS_SRIO:
4588		Chip has SRIO or not
4589
4590- CONFIG_SRIO1:
4591		Board has SRIO 1 port available
4592
4593- CONFIG_SRIO2:
4594		Board has SRIO 2 port available
4595
4596- CONFIG_SRIO_PCIE_BOOT_MASTER
4597		Board can support master function for Boot from SRIO and PCIE
4598
4599- CONFIG_SYS_SRIOn_MEM_VIRT:
4600		Virtual Address of SRIO port 'n' memory region
4601
4602- CONFIG_SYS_SRIOn_MEM_PHYS:
4603		Physical Address of SRIO port 'n' memory region
4604
4605- CONFIG_SYS_SRIOn_MEM_SIZE:
4606		Size of SRIO port 'n' memory region
4607
4608- CONFIG_SYS_NAND_BUSWIDTH_16BIT
4609		Defined to tell the NAND controller that the NAND chip is using
4610		a 16 bit bus.
4611		Not all NAND drivers use this symbol.
4612		Example of drivers that use it:
4613		- drivers/mtd/nand/ndfc.c
4614		- drivers/mtd/nand/mxc_nand.c
4615
4616- CONFIG_SYS_NDFC_EBC0_CFG
4617		Sets the EBC0_CFG register for the NDFC. If not defined
4618		a default value will be used.
4619
4620- CONFIG_SPD_EEPROM
4621		Get DDR timing information from an I2C EEPROM. Common
4622		with pluggable memory modules such as SODIMMs
4623
4624  SPD_EEPROM_ADDRESS
4625		I2C address of the SPD EEPROM
4626
4627- CONFIG_SYS_SPD_BUS_NUM
4628		If SPD EEPROM is on an I2C bus other than the first
4629		one, specify here. Note that the value must resolve
4630		to something your driver can deal with.
4631
4632- CONFIG_SYS_DDR_RAW_TIMING
4633		Get DDR timing information from other than SPD. Common with
4634		soldered DDR chips onboard without SPD. DDR raw timing
4635		parameters are extracted from datasheet and hard-coded into
4636		header files or board specific files.
4637
4638- CONFIG_FSL_DDR_INTERACTIVE
4639		Enable interactive DDR debugging. See doc/README.fsl-ddr.
4640
4641- CONFIG_FSL_DDR_SYNC_REFRESH
4642		Enable sync of refresh for multiple controllers.
4643
4644- CONFIG_FSL_DDR_BIST
4645		Enable built-in memory test for Freescale DDR controllers.
4646
4647- CONFIG_SYS_83XX_DDR_USES_CS0
4648		Only for 83xx systems. If specified, then DDR should
4649		be configured using CS0 and CS1 instead of CS2 and CS3.
4650
4651- CONFIG_ETHER_ON_FEC[12]
4652		Define to enable FEC[12] on a 8xx series processor.
4653
4654- CONFIG_FEC[12]_PHY
4655		Define to the hardcoded PHY address which corresponds
4656		to the given FEC; i. e.
4657			#define CONFIG_FEC1_PHY 4
4658		means that the PHY with address 4 is connected to FEC1
4659
4660		When set to -1, means to probe for first available.
4661
4662- CONFIG_FEC[12]_PHY_NORXERR
4663		The PHY does not have a RXERR line (RMII only).
4664		(so program the FEC to ignore it).
4665
4666- CONFIG_RMII
4667		Enable RMII mode for all FECs.
4668		Note that this is a global option, we can't
4669		have one FEC in standard MII mode and another in RMII mode.
4670
4671- CONFIG_CRC32_VERIFY
4672		Add a verify option to the crc32 command.
4673		The syntax is:
4674
4675		=> crc32 -v <address> <count> <crc32>
4676
4677		Where address/count indicate a memory area
4678		and crc32 is the correct crc32 which the
4679		area should have.
4680
4681- CONFIG_LOOPW
4682		Add the "loopw" memory command. This only takes effect if
4683		the memory commands are activated globally (CONFIG_CMD_MEM).
4684
4685- CONFIG_MX_CYCLIC
4686		Add the "mdc" and "mwc" memory commands. These are cyclic
4687		"md/mw" commands.
4688		Examples:
4689
4690		=> mdc.b 10 4 500
4691		This command will print 4 bytes (10,11,12,13) each 500 ms.
4692
4693		=> mwc.l 100 12345678 10
4694		This command will write 12345678 to address 100 all 10 ms.
4695
4696		This only takes effect if the memory commands are activated
4697		globally (CONFIG_CMD_MEM).
4698
4699- CONFIG_SKIP_LOWLEVEL_INIT
4700		[ARM, NDS32, MIPS only] If this variable is defined, then certain
4701		low level initializations (like setting up the memory
4702		controller) are omitted and/or U-Boot does not
4703		relocate itself into RAM.
4704
4705		Normally this variable MUST NOT be defined. The only
4706		exception is when U-Boot is loaded (to RAM) by some
4707		other boot loader or by a debugger which performs
4708		these initializations itself.
4709
4710- CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4711		[ARM926EJ-S only] This allows just the call to lowlevel_init()
4712		to be skipped. The normal CP15 init (such as enabling the
4713		instruction cache) is still performed.
4714
4715- CONFIG_SPL_BUILD
4716		Modifies the behaviour of start.S when compiling a loader
4717		that is executed before the actual U-Boot. E.g. when
4718		compiling a NAND SPL.
4719
4720- CONFIG_TPL_BUILD
4721		Modifies the behaviour of start.S  when compiling a loader
4722		that is executed after the SPL and before the actual U-Boot.
4723		It is loaded by the SPL.
4724
4725- CONFIG_SYS_MPC85XX_NO_RESETVEC
4726		Only for 85xx systems. If this variable is specified, the section
4727		.resetvec is not kept and the section .bootpg is placed in the
4728		previous 4k of the .text section.
4729
4730- CONFIG_ARCH_MAP_SYSMEM
4731		Generally U-Boot (and in particular the md command) uses
4732		effective address. It is therefore not necessary to regard
4733		U-Boot address as virtual addresses that need to be translated
4734		to physical addresses. However, sandbox requires this, since
4735		it maintains its own little RAM buffer which contains all
4736		addressable memory. This option causes some memory accesses
4737		to be mapped through map_sysmem() / unmap_sysmem().
4738
4739- CONFIG_USE_ARCH_MEMCPY
4740  CONFIG_USE_ARCH_MEMSET
4741		If these options are used a optimized version of memcpy/memset will
4742		be used if available. These functions may be faster under some
4743		conditions but may increase the binary size.
4744
4745- CONFIG_X86_RESET_VECTOR
4746		If defined, the x86 reset vector code is included. This is not
4747		needed when U-Boot is running from Coreboot.
4748
4749- CONFIG_SYS_MPUCLK
4750		Defines the MPU clock speed (in MHz).
4751
4752		NOTE : currently only supported on AM335x platforms.
4753
4754- CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4755		Enables the RTC32K OSC on AM33xx based plattforms
4756
4757- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4758		Option to disable subpage write in NAND driver
4759		driver that uses this:
4760		drivers/mtd/nand/davinci_nand.c
4761
4762Freescale QE/FMAN Firmware Support:
4763-----------------------------------
4764
4765The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4766loading of "firmware", which is encoded in the QE firmware binary format.
4767This firmware often needs to be loaded during U-Boot booting, so macros
4768are used to identify the storage device (NOR flash, SPI, etc) and the address
4769within that device.
4770
4771- CONFIG_SYS_FMAN_FW_ADDR
4772	The address in the storage device where the FMAN microcode is located.  The
4773	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4774	is also specified.
4775
4776- CONFIG_SYS_QE_FW_ADDR
4777	The address in the storage device where the QE microcode is located.  The
4778	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4779	is also specified.
4780
4781- CONFIG_SYS_QE_FMAN_FW_LENGTH
4782	The maximum possible size of the firmware.  The firmware binary format
4783	has a field that specifies the actual size of the firmware, but it
4784	might not be possible to read any part of the firmware unless some
4785	local storage is allocated to hold the entire firmware first.
4786
4787- CONFIG_SYS_QE_FMAN_FW_IN_NOR
4788	Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4789	normal addressable memory via the LBC.  CONFIG_SYS_FMAN_FW_ADDR is the
4790	virtual address in NOR flash.
4791
4792- CONFIG_SYS_QE_FMAN_FW_IN_NAND
4793	Specifies that QE/FMAN firmware is located in NAND flash.
4794	CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4795
4796- CONFIG_SYS_QE_FMAN_FW_IN_MMC
4797	Specifies that QE/FMAN firmware is located on the primary SD/MMC
4798	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4799
4800- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4801	Specifies that QE/FMAN firmware is located in the remote (master)
4802	memory space.	CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4803	can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4804	window->master inbound window->master LAW->the ucode address in
4805	master's memory space.
4806
4807Freescale Layerscape Management Complex Firmware Support:
4808---------------------------------------------------------
4809The Freescale Layerscape Management Complex (MC) supports the loading of
4810"firmware".
4811This firmware often needs to be loaded during U-Boot booting, so macros
4812are used to identify the storage device (NOR flash, SPI, etc) and the address
4813within that device.
4814
4815- CONFIG_FSL_MC_ENET
4816	Enable the MC driver for Layerscape SoCs.
4817
4818Freescale Layerscape Debug Server Support:
4819-------------------------------------------
4820The Freescale Layerscape Debug Server Support supports the loading of
4821"Debug Server firmware" and triggering SP boot-rom.
4822This firmware often needs to be loaded during U-Boot booting.
4823
4824- CONFIG_SYS_MC_RSV_MEM_ALIGN
4825	Define alignment of reserved memory MC requires
4826
4827Reproducible builds
4828-------------------
4829
4830In order to achieve reproducible builds, timestamps used in the U-Boot build
4831process have to be set to a fixed value.
4832
4833This is done using the SOURCE_DATE_EPOCH environment variable.
4834SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4835option for U-Boot or an environment variable in U-Boot.
4836
4837SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4838
4839Building the Software:
4840======================
4841
4842Building U-Boot has been tested in several native build environments
4843and in many different cross environments. Of course we cannot support
4844all possibly existing versions of cross development tools in all
4845(potentially obsolete) versions. In case of tool chain problems we
4846recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4847which is extensively used to build and test U-Boot.
4848
4849If you are not using a native environment, it is assumed that you
4850have GNU cross compiling tools available in your path. In this case,
4851you must set the environment variable CROSS_COMPILE in your shell.
4852Note that no changes to the Makefile or any other source files are
4853necessary. For example using the ELDK on a 4xx CPU, please enter:
4854
4855	$ CROSS_COMPILE=ppc_4xx-
4856	$ export CROSS_COMPILE
4857
4858Note: If you wish to generate Windows versions of the utilities in
4859      the tools directory you can use the MinGW toolchain
4860      (http://www.mingw.org).  Set your HOST tools to the MinGW
4861      toolchain and execute 'make tools'.  For example:
4862
4863       $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4864
4865      Binaries such as tools/mkimage.exe will be created which can
4866      be executed on computers running Windows.
4867
4868U-Boot is intended to be simple to build. After installing the
4869sources you must configure U-Boot for one specific board type. This
4870is done by typing:
4871
4872	make NAME_defconfig
4873
4874where "NAME_defconfig" is the name of one of the existing configu-
4875rations; see boards.cfg for supported names.
4876
4877Note: for some board special configuration names may exist; check if
4878      additional information is available from the board vendor; for
4879      instance, the TQM823L systems are available without (standard)
4880      or with LCD support. You can select such additional "features"
4881      when choosing the configuration, i. e.
4882
4883      make TQM823L_defconfig
4884	- will configure for a plain TQM823L, i. e. no LCD support
4885
4886      make TQM823L_LCD_defconfig
4887	- will configure for a TQM823L with U-Boot console on LCD
4888
4889      etc.
4890
4891
4892Finally, type "make all", and you should get some working U-Boot
4893images ready for download to / installation on your system:
4894
4895- "u-boot.bin" is a raw binary image
4896- "u-boot" is an image in ELF binary format
4897- "u-boot.srec" is in Motorola S-Record format
4898
4899By default the build is performed locally and the objects are saved
4900in the source directory. One of the two methods can be used to change
4901this behavior and build U-Boot to some external directory:
4902
49031. Add O= to the make command line invocations:
4904
4905	make O=/tmp/build distclean
4906	make O=/tmp/build NAME_defconfig
4907	make O=/tmp/build all
4908
49092. Set environment variable KBUILD_OUTPUT to point to the desired location:
4910
4911	export KBUILD_OUTPUT=/tmp/build
4912	make distclean
4913	make NAME_defconfig
4914	make all
4915
4916Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4917variable.
4918
4919
4920Please be aware that the Makefiles assume you are using GNU make, so
4921for instance on NetBSD you might need to use "gmake" instead of
4922native "make".
4923
4924
4925If the system board that you have is not listed, then you will need
4926to port U-Boot to your hardware platform. To do this, follow these
4927steps:
4928
49291.  Create a new directory to hold your board specific code. Add any
4930    files you need. In your board directory, you will need at least
4931    the "Makefile" and a "<board>.c".
49322.  Create a new configuration file "include/configs/<board>.h" for
4933    your board.
49343.  If you're porting U-Boot to a new CPU, then also create a new
4935    directory to hold your CPU specific code. Add any files you need.
49364.  Run "make <board>_defconfig" with your new name.
49375.  Type "make", and you should get a working "u-boot.srec" file
4938    to be installed on your target system.
49396.  Debug and solve any problems that might arise.
4940    [Of course, this last step is much harder than it sounds.]
4941
4942
4943Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4944==============================================================
4945
4946If you have modified U-Boot sources (for instance added a new board
4947or support for new devices, a new CPU, etc.) you are expected to
4948provide feedback to the other developers. The feedback normally takes
4949the form of a "patch", i. e. a context diff against a certain (latest
4950official or latest in the git repository) version of U-Boot sources.
4951
4952But before you submit such a patch, please verify that your modifi-
4953cation did not break existing code. At least make sure that *ALL* of
4954the supported boards compile WITHOUT ANY compiler warnings. To do so,
4955just run the buildman script (tools/buildman/buildman), which will
4956configure and build U-Boot for ALL supported system. Be warned, this
4957will take a while. Please see the buildman README, or run 'buildman -H'
4958for documentation.
4959
4960
4961See also "U-Boot Porting Guide" below.
4962
4963
4964Monitor Commands - Overview:
4965============================
4966
4967go	- start application at address 'addr'
4968run	- run commands in an environment variable
4969bootm	- boot application image from memory
4970bootp	- boot image via network using BootP/TFTP protocol
4971bootz   - boot zImage from memory
4972tftpboot- boot image via network using TFTP protocol
4973	       and env variables "ipaddr" and "serverip"
4974	       (and eventually "gatewayip")
4975tftpput - upload a file via network using TFTP protocol
4976rarpboot- boot image via network using RARP/TFTP protocol
4977diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
4978loads	- load S-Record file over serial line
4979loadb	- load binary file over serial line (kermit mode)
4980md	- memory display
4981mm	- memory modify (auto-incrementing)
4982nm	- memory modify (constant address)
4983mw	- memory write (fill)
4984cp	- memory copy
4985cmp	- memory compare
4986crc32	- checksum calculation
4987i2c	- I2C sub-system
4988sspi	- SPI utility commands
4989base	- print or set address offset
4990printenv- print environment variables
4991setenv	- set environment variables
4992saveenv - save environment variables to persistent storage
4993protect - enable or disable FLASH write protection
4994erase	- erase FLASH memory
4995flinfo	- print FLASH memory information
4996nand	- NAND memory operations (see doc/README.nand)
4997bdinfo	- print Board Info structure
4998iminfo	- print header information for application image
4999coninfo - print console devices and informations
5000ide	- IDE sub-system
5001loop	- infinite loop on address range
5002loopw	- infinite write loop on address range
5003mtest	- simple RAM test
5004icache	- enable or disable instruction cache
5005dcache	- enable or disable data cache
5006reset	- Perform RESET of the CPU
5007echo	- echo args to console
5008version - print monitor version
5009help	- print online help
5010?	- alias for 'help'
5011
5012
5013Monitor Commands - Detailed Description:
5014========================================
5015
5016TODO.
5017
5018For now: just type "help <command>".
5019
5020
5021Environment Variables:
5022======================
5023
5024U-Boot supports user configuration using Environment Variables which
5025can be made persistent by saving to Flash memory.
5026
5027Environment Variables are set using "setenv", printed using
5028"printenv", and saved to Flash using "saveenv". Using "setenv"
5029without a value can be used to delete a variable from the
5030environment. As long as you don't save the environment you are
5031working with an in-memory copy. In case the Flash area containing the
5032environment is erased by accident, a default environment is provided.
5033
5034Some configuration options can be set using Environment Variables.
5035
5036List of environment variables (most likely not complete):
5037
5038  baudrate	- see CONFIG_BAUDRATE
5039
5040  bootdelay	- see CONFIG_BOOTDELAY
5041
5042  bootcmd	- see CONFIG_BOOTCOMMAND
5043
5044  bootargs	- Boot arguments when booting an RTOS image
5045
5046  bootfile	- Name of the image to load with TFTP
5047
5048  bootm_low	- Memory range available for image processing in the bootm
5049		  command can be restricted. This variable is given as
5050		  a hexadecimal number and defines lowest address allowed
5051		  for use by the bootm command. See also "bootm_size"
5052		  environment variable. Address defined by "bootm_low" is
5053		  also the base of the initial memory mapping for the Linux
5054		  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5055		  bootm_mapsize.
5056
5057  bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5058		  This variable is given as a hexadecimal number and it
5059		  defines the size of the memory region starting at base
5060		  address bootm_low that is accessible by the Linux kernel
5061		  during early boot.  If unset, CONFIG_SYS_BOOTMAPSZ is used
5062		  as the default value if it is defined, and bootm_size is
5063		  used otherwise.
5064
5065  bootm_size	- Memory range available for image processing in the bootm
5066		  command can be restricted. This variable is given as
5067		  a hexadecimal number and defines the size of the region
5068		  allowed for use by the bootm command. See also "bootm_low"
5069		  environment variable.
5070
5071  updatefile	- Location of the software update file on a TFTP server, used
5072		  by the automatic software update feature. Please refer to
5073		  documentation in doc/README.update for more details.
5074
5075  autoload	- if set to "no" (any string beginning with 'n'),
5076		  "bootp" will just load perform a lookup of the
5077		  configuration from the BOOTP server, but not try to
5078		  load any image using TFTP
5079
5080  autostart	- if set to "yes", an image loaded using the "bootp",
5081		  "rarpboot", "tftpboot" or "diskboot" commands will
5082		  be automatically started (by internally calling
5083		  "bootm")
5084
5085		  If set to "no", a standalone image passed to the
5086		  "bootm" command will be copied to the load address
5087		  (and eventually uncompressed), but NOT be started.
5088		  This can be used to load and uncompress arbitrary
5089		  data.
5090
5091  fdt_high	- if set this restricts the maximum address that the
5092		  flattened device tree will be copied into upon boot.
5093		  For example, if you have a system with 1 GB memory
5094		  at physical address 0x10000000, while Linux kernel
5095		  only recognizes the first 704 MB as low memory, you
5096		  may need to set fdt_high as 0x3C000000 to have the
5097		  device tree blob be copied to the maximum address
5098		  of the 704 MB low memory, so that Linux kernel can
5099		  access it during the boot procedure.
5100
5101		  If this is set to the special value 0xFFFFFFFF then
5102		  the fdt will not be copied at all on boot.  For this
5103		  to work it must reside in writable memory, have
5104		  sufficient padding on the end of it for u-boot to
5105		  add the information it needs into it, and the memory
5106		  must be accessible by the kernel.
5107
5108  fdtcontroladdr- if set this is the address of the control flattened
5109		  device tree used by U-Boot when CONFIG_OF_CONTROL is
5110		  defined.
5111
5112  i2cfast	- (PPC405GP|PPC405EP only)
5113		  if set to 'y' configures Linux I2C driver for fast
5114		  mode (400kHZ). This environment variable is used in
5115		  initialization code. So, for changes to be effective
5116		  it must be saved and board must be reset.
5117
5118  initrd_high	- restrict positioning of initrd images:
5119		  If this variable is not set, initrd images will be
5120		  copied to the highest possible address in RAM; this
5121		  is usually what you want since it allows for
5122		  maximum initrd size. If for some reason you want to
5123		  make sure that the initrd image is loaded below the
5124		  CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5125		  variable to a value of "no" or "off" or "0".
5126		  Alternatively, you can set it to a maximum upper
5127		  address to use (U-Boot will still check that it
5128		  does not overwrite the U-Boot stack and data).
5129
5130		  For instance, when you have a system with 16 MB
5131		  RAM, and want to reserve 4 MB from use by Linux,
5132		  you can do this by adding "mem=12M" to the value of
5133		  the "bootargs" variable. However, now you must make
5134		  sure that the initrd image is placed in the first
5135		  12 MB as well - this can be done with
5136
5137		  setenv initrd_high 00c00000
5138
5139		  If you set initrd_high to 0xFFFFFFFF, this is an
5140		  indication to U-Boot that all addresses are legal
5141		  for the Linux kernel, including addresses in flash
5142		  memory. In this case U-Boot will NOT COPY the
5143		  ramdisk at all. This may be useful to reduce the
5144		  boot time on your system, but requires that this
5145		  feature is supported by your Linux kernel.
5146
5147  ipaddr	- IP address; needed for tftpboot command
5148
5149  loadaddr	- Default load address for commands like "bootp",
5150		  "rarpboot", "tftpboot", "loadb" or "diskboot"
5151
5152  loads_echo	- see CONFIG_LOADS_ECHO
5153
5154  serverip	- TFTP server IP address; needed for tftpboot command
5155
5156  bootretry	- see CONFIG_BOOT_RETRY_TIME
5157
5158  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
5159
5160  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
5161
5162  ethprime	- controls which interface is used first.
5163
5164  ethact	- controls which interface is currently active.
5165		  For example you can do the following
5166
5167		  => setenv ethact FEC
5168		  => ping 192.168.0.1 # traffic sent on FEC
5169		  => setenv ethact SCC
5170		  => ping 10.0.0.1 # traffic sent on SCC
5171
5172  ethrotate	- When set to "no" U-Boot does not go through all
5173		  available network interfaces.
5174		  It just stays at the currently selected interface.
5175
5176  netretry	- When set to "no" each network operation will
5177		  either succeed or fail without retrying.
5178		  When set to "once" the network operation will
5179		  fail when all the available network interfaces
5180		  are tried once without success.
5181		  Useful on scripts which control the retry operation
5182		  themselves.
5183
5184  npe_ucode	- set load address for the NPE microcode
5185
5186  silent_linux  - If set then Linux will be told to boot silently, by
5187		  changing the console to be empty. If "yes" it will be
5188		  made silent. If "no" it will not be made silent. If
5189		  unset, then it will be made silent if the U-Boot console
5190		  is silent.
5191
5192  tftpsrcp	- If this is set, the value is used for TFTP's
5193		  UDP source port.
5194
5195  tftpdstp	- If this is set, the value is used for TFTP's UDP
5196		  destination port instead of the Well Know Port 69.
5197
5198  tftpblocksize - Block size to use for TFTP transfers; if not set,
5199		  we use the TFTP server's default block size
5200
5201  tftptimeout	- Retransmission timeout for TFTP packets (in milli-
5202		  seconds, minimum value is 1000 = 1 second). Defines
5203		  when a packet is considered to be lost so it has to
5204		  be retransmitted. The default is 5000 = 5 seconds.
5205		  Lowering this value may make downloads succeed
5206		  faster in networks with high packet loss rates or
5207		  with unreliable TFTP servers.
5208
5209  tftptimeoutcountmax	- maximum count of TFTP timeouts (no
5210		  unit, minimum value = 0). Defines how many timeouts
5211		  can happen during a single file transfer before that
5212		  transfer is aborted. The default is 10, and 0 means
5213		  'no timeouts allowed'. Increasing this value may help
5214		  downloads succeed with high packet loss rates, or with
5215		  unreliable TFTP servers or client hardware.
5216
5217  vlan		- When set to a value < 4095 the traffic over
5218		  Ethernet is encapsulated/received over 802.1q
5219		  VLAN tagged frames.
5220
5221  bootpretryperiod	- Period during which BOOTP/DHCP sends retries.
5222		  Unsigned value, in milliseconds. If not set, the period will
5223		  be either the default (28000), or a value based on
5224		  CONFIG_NET_RETRY_COUNT, if defined. This value has
5225		  precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5226
5227The following image location variables contain the location of images
5228used in booting. The "Image" column gives the role of the image and is
5229not an environment variable name. The other columns are environment
5230variable names. "File Name" gives the name of the file on a TFTP
5231server, "RAM Address" gives the location in RAM the image will be
5232loaded to, and "Flash Location" gives the image's address in NOR
5233flash or offset in NAND flash.
5234
5235*Note* - these variables don't have to be defined for all boards, some
5236boards currently use other variables for these purposes, and some
5237boards use these variables for other purposes.
5238
5239Image		    File Name	     RAM Address       Flash Location
5240-----		    ---------	     -----------       --------------
5241u-boot		    u-boot	     u-boot_addr_r     u-boot_addr
5242Linux kernel	    bootfile	     kernel_addr_r     kernel_addr
5243device tree blob    fdtfile	     fdt_addr_r	       fdt_addr
5244ramdisk		    ramdiskfile	     ramdisk_addr_r    ramdisk_addr
5245
5246The following environment variables may be used and automatically
5247updated by the network boot commands ("bootp" and "rarpboot"),
5248depending the information provided by your boot server:
5249
5250  bootfile	- see above
5251  dnsip		- IP address of your Domain Name Server
5252  dnsip2	- IP address of your secondary Domain Name Server
5253  gatewayip	- IP address of the Gateway (Router) to use
5254  hostname	- Target hostname
5255  ipaddr	- see above
5256  netmask	- Subnet Mask
5257  rootpath	- Pathname of the root filesystem on the NFS server
5258  serverip	- see above
5259
5260
5261There are two special Environment Variables:
5262
5263  serial#	- contains hardware identification information such
5264		  as type string and/or serial number
5265  ethaddr	- Ethernet address
5266
5267These variables can be set only once (usually during manufacturing of
5268the board). U-Boot refuses to delete or overwrite these variables
5269once they have been set once.
5270
5271
5272Further special Environment Variables:
5273
5274  ver		- Contains the U-Boot version string as printed
5275		  with the "version" command. This variable is
5276		  readonly (see CONFIG_VERSION_VARIABLE).
5277
5278
5279Please note that changes to some configuration parameters may take
5280only effect after the next boot (yes, that's just like Windoze :-).
5281
5282
5283Callback functions for environment variables:
5284---------------------------------------------
5285
5286For some environment variables, the behavior of u-boot needs to change
5287when their values are changed.  This functionality allows functions to
5288be associated with arbitrary variables.  On creation, overwrite, or
5289deletion, the callback will provide the opportunity for some side
5290effect to happen or for the change to be rejected.
5291
5292The callbacks are named and associated with a function using the
5293U_BOOT_ENV_CALLBACK macro in your board or driver code.
5294
5295These callbacks are associated with variables in one of two ways.  The
5296static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5297in the board configuration to a string that defines a list of
5298associations.  The list must be in the following format:
5299
5300	entry = variable_name[:callback_name]
5301	list = entry[,list]
5302
5303If the callback name is not specified, then the callback is deleted.
5304Spaces are also allowed anywhere in the list.
5305
5306Callbacks can also be associated by defining the ".callbacks" variable
5307with the same list format above.  Any association in ".callbacks" will
5308override any association in the static list. You can define
5309CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5310".callbacks" environment variable in the default or embedded environment.
5311
5312If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5313regular expression. This allows multiple variables to be connected to
5314the same callback without explicitly listing them all out.
5315
5316
5317Command Line Parsing:
5318=====================
5319
5320There are two different command line parsers available with U-Boot:
5321the old "simple" one, and the much more powerful "hush" shell:
5322
5323Old, simple command line parser:
5324--------------------------------
5325
5326- supports environment variables (through setenv / saveenv commands)
5327- several commands on one line, separated by ';'
5328- variable substitution using "... ${name} ..." syntax
5329- special characters ('$', ';') can be escaped by prefixing with '\',
5330  for example:
5331	setenv bootcmd bootm \${address}
5332- You can also escape text by enclosing in single apostrophes, for example:
5333	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5334
5335Hush shell:
5336-----------
5337
5338- similar to Bourne shell, with control structures like
5339  if...then...else...fi, for...do...done; while...do...done,
5340  until...do...done, ...
5341- supports environment ("global") variables (through setenv / saveenv
5342  commands) and local shell variables (through standard shell syntax
5343  "name=value"); only environment variables can be used with "run"
5344  command
5345
5346General rules:
5347--------------
5348
5349(1) If a command line (or an environment variable executed by a "run"
5350    command) contains several commands separated by semicolon, and
5351    one of these commands fails, then the remaining commands will be
5352    executed anyway.
5353
5354(2) If you execute several variables with one call to run (i. e.
5355    calling run with a list of variables as arguments), any failing
5356    command will cause "run" to terminate, i. e. the remaining
5357    variables are not executed.
5358
5359Note for Redundant Ethernet Interfaces:
5360=======================================
5361
5362Some boards come with redundant Ethernet interfaces; U-Boot supports
5363such configurations and is capable of automatic selection of a
5364"working" interface when needed. MAC assignment works as follows:
5365
5366Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5367MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5368"eth1addr" (=>eth1), "eth2addr", ...
5369
5370If the network interface stores some valid MAC address (for instance
5371in SROM), this is used as default address if there is NO correspon-
5372ding setting in the environment; if the corresponding environment
5373variable is set, this overrides the settings in the card; that means:
5374
5375o If the SROM has a valid MAC address, and there is no address in the
5376  environment, the SROM's address is used.
5377
5378o If there is no valid address in the SROM, and a definition in the
5379  environment exists, then the value from the environment variable is
5380  used.
5381
5382o If both the SROM and the environment contain a MAC address, and
5383  both addresses are the same, this MAC address is used.
5384
5385o If both the SROM and the environment contain a MAC address, and the
5386  addresses differ, the value from the environment is used and a
5387  warning is printed.
5388
5389o If neither SROM nor the environment contain a MAC address, an error
5390  is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5391  a random, locally-assigned MAC is used.
5392
5393If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5394will be programmed into hardware as part of the initialization process.	 This
5395may be skipped by setting the appropriate 'ethmacskip' environment variable.
5396The naming convention is as follows:
5397"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5398
5399Image Formats:
5400==============
5401
5402U-Boot is capable of booting (and performing other auxiliary operations on)
5403images in two formats:
5404
5405New uImage format (FIT)
5406-----------------------
5407
5408Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5409to Flattened Device Tree). It allows the use of images with multiple
5410components (several kernels, ramdisks, etc.), with contents protected by
5411SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5412
5413
5414Old uImage format
5415-----------------
5416
5417Old image format is based on binary files which can be basically anything,
5418preceded by a special header; see the definitions in include/image.h for
5419details; basically, the header defines the following image properties:
5420
5421* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5422  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5423  LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5424  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5425  INTEGRITY).
5426* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5427  IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5428  Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5429* Compression Type (uncompressed, gzip, bzip2)
5430* Load Address
5431* Entry Point
5432* Image Name
5433* Image Timestamp
5434
5435The header is marked by a special Magic Number, and both the header
5436and the data portions of the image are secured against corruption by
5437CRC32 checksums.
5438
5439
5440Linux Support:
5441==============
5442
5443Although U-Boot should support any OS or standalone application
5444easily, the main focus has always been on Linux during the design of
5445U-Boot.
5446
5447U-Boot includes many features that so far have been part of some
5448special "boot loader" code within the Linux kernel. Also, any
5449"initrd" images to be used are no longer part of one big Linux image;
5450instead, kernel and "initrd" are separate images. This implementation
5451serves several purposes:
5452
5453- the same features can be used for other OS or standalone
5454  applications (for instance: using compressed images to reduce the
5455  Flash memory footprint)
5456
5457- it becomes much easier to port new Linux kernel versions because
5458  lots of low-level, hardware dependent stuff are done by U-Boot
5459
5460- the same Linux kernel image can now be used with different "initrd"
5461  images; of course this also means that different kernel images can
5462  be run with the same "initrd". This makes testing easier (you don't
5463  have to build a new "zImage.initrd" Linux image when you just
5464  change a file in your "initrd"). Also, a field-upgrade of the
5465  software is easier now.
5466
5467
5468Linux HOWTO:
5469============
5470
5471Porting Linux to U-Boot based systems:
5472---------------------------------------
5473
5474U-Boot cannot save you from doing all the necessary modifications to
5475configure the Linux device drivers for use with your target hardware
5476(no, we don't intend to provide a full virtual machine interface to
5477Linux :-).
5478
5479But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5480
5481Just make sure your machine specific header file (for instance
5482include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5483Information structure as we define in include/asm-<arch>/u-boot.h,
5484and make sure that your definition of IMAP_ADDR uses the same value
5485as your U-Boot configuration in CONFIG_SYS_IMMR.
5486
5487Note that U-Boot now has a driver model, a unified model for drivers.
5488If you are adding a new driver, plumb it into driver model. If there
5489is no uclass available, you are encouraged to create one. See
5490doc/driver-model.
5491
5492
5493Configuring the Linux kernel:
5494-----------------------------
5495
5496No specific requirements for U-Boot. Make sure you have some root
5497device (initial ramdisk, NFS) for your target system.
5498
5499
5500Building a Linux Image:
5501-----------------------
5502
5503With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5504not used. If you use recent kernel source, a new build target
5505"uImage" will exist which automatically builds an image usable by
5506U-Boot. Most older kernels also have support for a "pImage" target,
5507which was introduced for our predecessor project PPCBoot and uses a
5508100% compatible format.
5509
5510Example:
5511
5512	make TQM850L_defconfig
5513	make oldconfig
5514	make dep
5515	make uImage
5516
5517The "uImage" build target uses a special tool (in 'tools/mkimage') to
5518encapsulate a compressed Linux kernel image with header	 information,
5519CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5520
5521* build a standard "vmlinux" kernel image (in ELF binary format):
5522
5523* convert the kernel into a raw binary image:
5524
5525	${CROSS_COMPILE}-objcopy -O binary \
5526				 -R .note -R .comment \
5527				 -S vmlinux linux.bin
5528
5529* compress the binary image:
5530
5531	gzip -9 linux.bin
5532
5533* package compressed binary image for U-Boot:
5534
5535	mkimage -A ppc -O linux -T kernel -C gzip \
5536		-a 0 -e 0 -n "Linux Kernel Image" \
5537		-d linux.bin.gz uImage
5538
5539
5540The "mkimage" tool can also be used to create ramdisk images for use
5541with U-Boot, either separated from the Linux kernel image, or
5542combined into one file. "mkimage" encapsulates the images with a 64
5543byte header containing information about target architecture,
5544operating system, image type, compression method, entry points, time
5545stamp, CRC32 checksums, etc.
5546
5547"mkimage" can be called in two ways: to verify existing images and
5548print the header information, or to build new images.
5549
5550In the first form (with "-l" option) mkimage lists the information
5551contained in the header of an existing U-Boot image; this includes
5552checksum verification:
5553
5554	tools/mkimage -l image
5555	  -l ==> list image header information
5556
5557The second form (with "-d" option) is used to build a U-Boot image
5558from a "data file" which is used as image payload:
5559
5560	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5561		      -n name -d data_file image
5562	  -A ==> set architecture to 'arch'
5563	  -O ==> set operating system to 'os'
5564	  -T ==> set image type to 'type'
5565	  -C ==> set compression type 'comp'
5566	  -a ==> set load address to 'addr' (hex)
5567	  -e ==> set entry point to 'ep' (hex)
5568	  -n ==> set image name to 'name'
5569	  -d ==> use image data from 'datafile'
5570
5571Right now, all Linux kernels for PowerPC systems use the same load
5572address (0x00000000), but the entry point address depends on the
5573kernel version:
5574
5575- 2.2.x kernels have the entry point at 0x0000000C,
5576- 2.3.x and later kernels have the entry point at 0x00000000.
5577
5578So a typical call to build a U-Boot image would read:
5579
5580	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5581	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5582	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5583	> examples/uImage.TQM850L
5584	Image Name:   2.4.4 kernel for TQM850L
5585	Created:      Wed Jul 19 02:34:59 2000
5586	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5587	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5588	Load Address: 0x00000000
5589	Entry Point:  0x00000000
5590
5591To verify the contents of the image (or check for corruption):
5592
5593	-> tools/mkimage -l examples/uImage.TQM850L
5594	Image Name:   2.4.4 kernel for TQM850L
5595	Created:      Wed Jul 19 02:34:59 2000
5596	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5597	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5598	Load Address: 0x00000000
5599	Entry Point:  0x00000000
5600
5601NOTE: for embedded systems where boot time is critical you can trade
5602speed for memory and install an UNCOMPRESSED image instead: this
5603needs more space in Flash, but boots much faster since it does not
5604need to be uncompressed:
5605
5606	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5607	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5608	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5609	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5610	> examples/uImage.TQM850L-uncompressed
5611	Image Name:   2.4.4 kernel for TQM850L
5612	Created:      Wed Jul 19 02:34:59 2000
5613	Image Type:   PowerPC Linux Kernel Image (uncompressed)
5614	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
5615	Load Address: 0x00000000
5616	Entry Point:  0x00000000
5617
5618
5619Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5620when your kernel is intended to use an initial ramdisk:
5621
5622	-> tools/mkimage -n 'Simple Ramdisk Image' \
5623	> -A ppc -O linux -T ramdisk -C gzip \
5624	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5625	Image Name:   Simple Ramdisk Image
5626	Created:      Wed Jan 12 14:01:50 2000
5627	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
5628	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
5629	Load Address: 0x00000000
5630	Entry Point:  0x00000000
5631
5632The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5633option performs the converse operation of the mkimage's second form (the "-d"
5634option). Given an image built by mkimage, the dumpimage extracts a "data file"
5635from the image:
5636
5637	tools/dumpimage -i image -T type -p position data_file
5638	  -i ==> extract from the 'image' a specific 'data_file'
5639	  -T ==> set image type to 'type'
5640	  -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5641
5642
5643Installing a Linux Image:
5644-------------------------
5645
5646To downloading a U-Boot image over the serial (console) interface,
5647you must convert the image to S-Record format:
5648
5649	objcopy -I binary -O srec examples/image examples/image.srec
5650
5651The 'objcopy' does not understand the information in the U-Boot
5652image header, so the resulting S-Record file will be relative to
5653address 0x00000000. To load it to a given address, you need to
5654specify the target address as 'offset' parameter with the 'loads'
5655command.
5656
5657Example: install the image to address 0x40100000 (which on the
5658TQM8xxL is in the first Flash bank):
5659
5660	=> erase 40100000 401FFFFF
5661
5662	.......... done
5663	Erased 8 sectors
5664
5665	=> loads 40100000
5666	## Ready for S-Record download ...
5667	~>examples/image.srec
5668	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5669	...
5670	15989 15990 15991 15992
5671	[file transfer complete]
5672	[connected]
5673	## Start Addr = 0x00000000
5674
5675
5676You can check the success of the download using the 'iminfo' command;
5677this includes a checksum verification so you can be sure no data
5678corruption happened:
5679
5680	=> imi 40100000
5681
5682	## Checking Image at 40100000 ...
5683	   Image Name:	 2.2.13 for initrd on TQM850L
5684	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5685	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5686	   Load Address: 00000000
5687	   Entry Point:	 0000000c
5688	   Verifying Checksum ... OK
5689
5690
5691Boot Linux:
5692-----------
5693
5694The "bootm" command is used to boot an application that is stored in
5695memory (RAM or Flash). In case of a Linux kernel image, the contents
5696of the "bootargs" environment variable is passed to the kernel as
5697parameters. You can check and modify this variable using the
5698"printenv" and "setenv" commands:
5699
5700
5701	=> printenv bootargs
5702	bootargs=root=/dev/ram
5703
5704	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5705
5706	=> printenv bootargs
5707	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5708
5709	=> bootm 40020000
5710	## Booting Linux kernel at 40020000 ...
5711	   Image Name:	 2.2.13 for NFS on TQM850L
5712	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5713	   Data Size:	 381681 Bytes = 372 kB = 0 MB
5714	   Load Address: 00000000
5715	   Entry Point:	 0000000c
5716	   Verifying Checksum ... OK
5717	   Uncompressing Kernel Image ... OK
5718	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
5719	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5720	time_init: decrementer frequency = 187500000/60
5721	Calibrating delay loop... 49.77 BogoMIPS
5722	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5723	...
5724
5725If you want to boot a Linux kernel with initial RAM disk, you pass
5726the memory addresses of both the kernel and the initrd image (PPBCOOT
5727format!) to the "bootm" command:
5728
5729	=> imi 40100000 40200000
5730
5731	## Checking Image at 40100000 ...
5732	   Image Name:	 2.2.13 for initrd on TQM850L
5733	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5734	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5735	   Load Address: 00000000
5736	   Entry Point:	 0000000c
5737	   Verifying Checksum ... OK
5738
5739	## Checking Image at 40200000 ...
5740	   Image Name:	 Simple Ramdisk Image
5741	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5742	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5743	   Load Address: 00000000
5744	   Entry Point:	 00000000
5745	   Verifying Checksum ... OK
5746
5747	=> bootm 40100000 40200000
5748	## Booting Linux kernel at 40100000 ...
5749	   Image Name:	 2.2.13 for initrd on TQM850L
5750	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5751	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5752	   Load Address: 00000000
5753	   Entry Point:	 0000000c
5754	   Verifying Checksum ... OK
5755	   Uncompressing Kernel Image ... OK
5756	## Loading RAMDisk Image at 40200000 ...
5757	   Image Name:	 Simple Ramdisk Image
5758	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5759	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5760	   Load Address: 00000000
5761	   Entry Point:	 00000000
5762	   Verifying Checksum ... OK
5763	   Loading Ramdisk ... OK
5764	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
5765	Boot arguments: root=/dev/ram
5766	time_init: decrementer frequency = 187500000/60
5767	Calibrating delay loop... 49.77 BogoMIPS
5768	...
5769	RAMDISK: Compressed image found at block 0
5770	VFS: Mounted root (ext2 filesystem).
5771
5772	bash#
5773
5774Boot Linux and pass a flat device tree:
5775-----------
5776
5777First, U-Boot must be compiled with the appropriate defines. See the section
5778titled "Linux Kernel Interface" above for a more in depth explanation. The
5779following is an example of how to start a kernel and pass an updated
5780flat device tree:
5781
5782=> print oftaddr
5783oftaddr=0x300000
5784=> print oft
5785oft=oftrees/mpc8540ads.dtb
5786=> tftp $oftaddr $oft
5787Speed: 1000, full duplex
5788Using TSEC0 device
5789TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5790Filename 'oftrees/mpc8540ads.dtb'.
5791Load address: 0x300000
5792Loading: #
5793done
5794Bytes transferred = 4106 (100a hex)
5795=> tftp $loadaddr $bootfile
5796Speed: 1000, full duplex
5797Using TSEC0 device
5798TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5799Filename 'uImage'.
5800Load address: 0x200000
5801Loading:############
5802done
5803Bytes transferred = 1029407 (fb51f hex)
5804=> print loadaddr
5805loadaddr=200000
5806=> print oftaddr
5807oftaddr=0x300000
5808=> bootm $loadaddr - $oftaddr
5809## Booting image at 00200000 ...
5810   Image Name:	 Linux-2.6.17-dirty
5811   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5812   Data Size:	 1029343 Bytes = 1005.2 kB
5813   Load Address: 00000000
5814   Entry Point:	 00000000
5815   Verifying Checksum ... OK
5816   Uncompressing Kernel Image ... OK
5817Booting using flat device tree at 0x300000
5818Using MPC85xx ADS machine description
5819Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5820[snip]
5821
5822
5823More About U-Boot Image Types:
5824------------------------------
5825
5826U-Boot supports the following image types:
5827
5828   "Standalone Programs" are directly runnable in the environment
5829	provided by U-Boot; it is expected that (if they behave
5830	well) you can continue to work in U-Boot after return from
5831	the Standalone Program.
5832   "OS Kernel Images" are usually images of some Embedded OS which
5833	will take over control completely. Usually these programs
5834	will install their own set of exception handlers, device
5835	drivers, set up the MMU, etc. - this means, that you cannot
5836	expect to re-enter U-Boot except by resetting the CPU.
5837   "RAMDisk Images" are more or less just data blocks, and their
5838	parameters (address, size) are passed to an OS kernel that is
5839	being started.
5840   "Multi-File Images" contain several images, typically an OS
5841	(Linux) kernel image and one or more data images like
5842	RAMDisks. This construct is useful for instance when you want
5843	to boot over the network using BOOTP etc., where the boot
5844	server provides just a single image file, but you want to get
5845	for instance an OS kernel and a RAMDisk image.
5846
5847	"Multi-File Images" start with a list of image sizes, each
5848	image size (in bytes) specified by an "uint32_t" in network
5849	byte order. This list is terminated by an "(uint32_t)0".
5850	Immediately after the terminating 0 follow the images, one by
5851	one, all aligned on "uint32_t" boundaries (size rounded up to
5852	a multiple of 4 bytes).
5853
5854   "Firmware Images" are binary images containing firmware (like
5855	U-Boot or FPGA images) which usually will be programmed to
5856	flash memory.
5857
5858   "Script files" are command sequences that will be executed by
5859	U-Boot's command interpreter; this feature is especially
5860	useful when you configure U-Boot to use a real shell (hush)
5861	as command interpreter.
5862
5863Booting the Linux zImage:
5864-------------------------
5865
5866On some platforms, it's possible to boot Linux zImage. This is done
5867using the "bootz" command. The syntax of "bootz" command is the same
5868as the syntax of "bootm" command.
5869
5870Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5871kernel with raw initrd images. The syntax is slightly different, the
5872address of the initrd must be augmented by it's size, in the following
5873format: "<initrd addres>:<initrd size>".
5874
5875
5876Standalone HOWTO:
5877=================
5878
5879One of the features of U-Boot is that you can dynamically load and
5880run "standalone" applications, which can use some resources of
5881U-Boot like console I/O functions or interrupt services.
5882
5883Two simple examples are included with the sources:
5884
5885"Hello World" Demo:
5886-------------------
5887
5888'examples/hello_world.c' contains a small "Hello World" Demo
5889application; it is automatically compiled when you build U-Boot.
5890It's configured to run at address 0x00040004, so you can play with it
5891like that:
5892
5893	=> loads
5894	## Ready for S-Record download ...
5895	~>examples/hello_world.srec
5896	1 2 3 4 5 6 7 8 9 10 11 ...
5897	[file transfer complete]
5898	[connected]
5899	## Start Addr = 0x00040004
5900
5901	=> go 40004 Hello World! This is a test.
5902	## Starting application at 0x00040004 ...
5903	Hello World
5904	argc = 7
5905	argv[0] = "40004"
5906	argv[1] = "Hello"
5907	argv[2] = "World!"
5908	argv[3] = "This"
5909	argv[4] = "is"
5910	argv[5] = "a"
5911	argv[6] = "test."
5912	argv[7] = "<NULL>"
5913	Hit any key to exit ...
5914
5915	## Application terminated, rc = 0x0
5916
5917Another example, which demonstrates how to register a CPM interrupt
5918handler with the U-Boot code, can be found in 'examples/timer.c'.
5919Here, a CPM timer is set up to generate an interrupt every second.
5920The interrupt service routine is trivial, just printing a '.'
5921character, but this is just a demo program. The application can be
5922controlled by the following keys:
5923
5924	? - print current values og the CPM Timer registers
5925	b - enable interrupts and start timer
5926	e - stop timer and disable interrupts
5927	q - quit application
5928
5929	=> loads
5930	## Ready for S-Record download ...
5931	~>examples/timer.srec
5932	1 2 3 4 5 6 7 8 9 10 11 ...
5933	[file transfer complete]
5934	[connected]
5935	## Start Addr = 0x00040004
5936
5937	=> go 40004
5938	## Starting application at 0x00040004 ...
5939	TIMERS=0xfff00980
5940	Using timer 1
5941	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5942
5943Hit 'b':
5944	[q, b, e, ?] Set interval 1000000 us
5945	Enabling timer
5946Hit '?':
5947	[q, b, e, ?] ........
5948	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5949Hit '?':
5950	[q, b, e, ?] .
5951	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5952Hit '?':
5953	[q, b, e, ?] .
5954	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5955Hit '?':
5956	[q, b, e, ?] .
5957	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5958Hit 'e':
5959	[q, b, e, ?] ...Stopping timer
5960Hit 'q':
5961	[q, b, e, ?] ## Application terminated, rc = 0x0
5962
5963
5964Minicom warning:
5965================
5966
5967Over time, many people have reported problems when trying to use the
5968"minicom" terminal emulation program for serial download. I (wd)
5969consider minicom to be broken, and recommend not to use it. Under
5970Unix, I recommend to use C-Kermit for general purpose use (and
5971especially for kermit binary protocol download ("loadb" command), and
5972use "cu" for S-Record download ("loads" command).  See
5973http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5974for help with kermit.
5975
5976
5977Nevertheless, if you absolutely want to use it try adding this
5978configuration to your "File transfer protocols" section:
5979
5980	   Name	   Program			Name U/D FullScr IO-Red. Multi
5981	X  kermit  /usr/bin/kermit -i -l %l -s	 Y    U	   Y	   N	  N
5982	Y  kermit  /usr/bin/kermit -i -l %l -r	 N    D	   Y	   N	  N
5983
5984
5985NetBSD Notes:
5986=============
5987
5988Starting at version 0.9.2, U-Boot supports NetBSD both as host
5989(build U-Boot) and target system (boots NetBSD/mpc8xx).
5990
5991Building requires a cross environment; it is known to work on
5992NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5993need gmake since the Makefiles are not compatible with BSD make).
5994Note that the cross-powerpc package does not install include files;
5995attempting to build U-Boot will fail because <machine/ansi.h> is
5996missing.  This file has to be installed and patched manually:
5997
5998	# cd /usr/pkg/cross/powerpc-netbsd/include
5999	# mkdir powerpc
6000	# ln -s powerpc machine
6001	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6002	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
6003
6004Native builds *don't* work due to incompatibilities between native
6005and U-Boot include files.
6006
6007Booting assumes that (the first part of) the image booted is a
6008stage-2 loader which in turn loads and then invokes the kernel
6009proper. Loader sources will eventually appear in the NetBSD source
6010tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6011meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6012
6013
6014Implementation Internals:
6015=========================
6016
6017The following is not intended to be a complete description of every
6018implementation detail. However, it should help to understand the
6019inner workings of U-Boot and make it easier to port it to custom
6020hardware.
6021
6022
6023Initial Stack, Global Data:
6024---------------------------
6025
6026The implementation of U-Boot is complicated by the fact that U-Boot
6027starts running out of ROM (flash memory), usually without access to
6028system RAM (because the memory controller is not initialized yet).
6029This means that we don't have writable Data or BSS segments, and BSS
6030is not initialized as zero. To be able to get a C environment working
6031at all, we have to allocate at least a minimal stack. Implementation
6032options for this are defined and restricted by the CPU used: Some CPU
6033models provide on-chip memory (like the IMMR area on MPC8xx and
6034MPC826x processors), on others (parts of) the data cache can be
6035locked as (mis-) used as memory, etc.
6036
6037	Chris Hallinan posted a good summary of these issues to the
6038	U-Boot mailing list:
6039
6040	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6041	From: "Chris Hallinan" <clh@net1plus.com>
6042	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6043	...
6044
6045	Correct me if I'm wrong, folks, but the way I understand it
6046	is this: Using DCACHE as initial RAM for Stack, etc, does not
6047	require any physical RAM backing up the cache. The cleverness
6048	is that the cache is being used as a temporary supply of
6049	necessary storage before the SDRAM controller is setup. It's
6050	beyond the scope of this list to explain the details, but you
6051	can see how this works by studying the cache architecture and
6052	operation in the architecture and processor-specific manuals.
6053
6054	OCM is On Chip Memory, which I believe the 405GP has 4K. It
6055	is another option for the system designer to use as an
6056	initial stack/RAM area prior to SDRAM being available. Either
6057	option should work for you. Using CS 4 should be fine if your
6058	board designers haven't used it for something that would
6059	cause you grief during the initial boot! It is frequently not
6060	used.
6061
6062	CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6063	with your processor/board/system design. The default value
6064	you will find in any recent u-boot distribution in
6065	walnut.h should work for you. I'd set it to a value larger
6066	than your SDRAM module. If you have a 64MB SDRAM module, set
6067	it above 400_0000. Just make sure your board has no resources
6068	that are supposed to respond to that address! That code in
6069	start.S has been around a while and should work as is when
6070	you get the config right.
6071
6072	-Chris Hallinan
6073	DS4.COM, Inc.
6074
6075It is essential to remember this, since it has some impact on the C
6076code for the initialization procedures:
6077
6078* Initialized global data (data segment) is read-only. Do not attempt
6079  to write it.
6080
6081* Do not use any uninitialized global data (or implicitly initialized
6082  as zero data - BSS segment) at all - this is undefined, initiali-
6083  zation is performed later (when relocating to RAM).
6084
6085* Stack space is very limited. Avoid big data buffers or things like
6086  that.
6087
6088Having only the stack as writable memory limits means we cannot use
6089normal global data to share information between the code. But it
6090turned out that the implementation of U-Boot can be greatly
6091simplified by making a global data structure (gd_t) available to all
6092functions. We could pass a pointer to this data as argument to _all_
6093functions, but this would bloat the code. Instead we use a feature of
6094the GCC compiler (Global Register Variables) to share the data: we
6095place a pointer (gd) to the global data into a register which we
6096reserve for this purpose.
6097
6098When choosing a register for such a purpose we are restricted by the
6099relevant  (E)ABI  specifications for the current architecture, and by
6100GCC's implementation.
6101
6102For PowerPC, the following registers have specific use:
6103	R1:	stack pointer
6104	R2:	reserved for system use
6105	R3-R4:	parameter passing and return values
6106	R5-R10: parameter passing
6107	R13:	small data area pointer
6108	R30:	GOT pointer
6109	R31:	frame pointer
6110
6111	(U-Boot also uses R12 as internal GOT pointer. r12
6112	is a volatile register so r12 needs to be reset when
6113	going back and forth between asm and C)
6114
6115    ==> U-Boot will use R2 to hold a pointer to the global data
6116
6117    Note: on PPC, we could use a static initializer (since the
6118    address of the global data structure is known at compile time),
6119    but it turned out that reserving a register results in somewhat
6120    smaller code - although the code savings are not that big (on
6121    average for all boards 752 bytes for the whole U-Boot image,
6122    624 text + 127 data).
6123
6124On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6125	http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6126
6127    ==> U-Boot will use P3 to hold a pointer to the global data
6128
6129On ARM, the following registers are used:
6130
6131	R0:	function argument word/integer result
6132	R1-R3:	function argument word
6133	R9:	platform specific
6134	R10:	stack limit (used only if stack checking is enabled)
6135	R11:	argument (frame) pointer
6136	R12:	temporary workspace
6137	R13:	stack pointer
6138	R14:	link register
6139	R15:	program counter
6140
6141    ==> U-Boot will use R9 to hold a pointer to the global data
6142
6143    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6144
6145On Nios II, the ABI is documented here:
6146	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6147
6148    ==> U-Boot will use gp to hold a pointer to the global data
6149
6150    Note: on Nios II, we give "-G0" option to gcc and don't use gp
6151    to access small data sections, so gp is free.
6152
6153On NDS32, the following registers are used:
6154
6155	R0-R1:	argument/return
6156	R2-R5:	argument
6157	R15:	temporary register for assembler
6158	R16:	trampoline register
6159	R28:	frame pointer (FP)
6160	R29:	global pointer (GP)
6161	R30:	link register (LP)
6162	R31:	stack pointer (SP)
6163	PC:	program counter (PC)
6164
6165    ==> U-Boot will use R10 to hold a pointer to the global data
6166
6167NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6168or current versions of GCC may "optimize" the code too much.
6169
6170Memory Management:
6171------------------
6172
6173U-Boot runs in system state and uses physical addresses, i.e. the
6174MMU is not used either for address mapping nor for memory protection.
6175
6176The available memory is mapped to fixed addresses using the memory
6177controller. In this process, a contiguous block is formed for each
6178memory type (Flash, SDRAM, SRAM), even when it consists of several
6179physical memory banks.
6180
6181U-Boot is installed in the first 128 kB of the first Flash bank (on
6182TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6183booting and sizing and initializing DRAM, the code relocates itself
6184to the upper end of DRAM. Immediately below the U-Boot code some
6185memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6186configuration setting]. Below that, a structure with global Board
6187Info data is placed, followed by the stack (growing downward).
6188
6189Additionally, some exception handler code is copied to the low 8 kB
6190of DRAM (0x00000000 ... 0x00001FFF).
6191
6192So a typical memory configuration with 16 MB of DRAM could look like
6193this:
6194
6195	0x0000 0000	Exception Vector code
6196	      :
6197	0x0000 1FFF
6198	0x0000 2000	Free for Application Use
6199	      :
6200	      :
6201
6202	      :
6203	      :
6204	0x00FB FF20	Monitor Stack (Growing downward)
6205	0x00FB FFAC	Board Info Data and permanent copy of global data
6206	0x00FC 0000	Malloc Arena
6207	      :
6208	0x00FD FFFF
6209	0x00FE 0000	RAM Copy of Monitor Code
6210	...		eventually: LCD or video framebuffer
6211	...		eventually: pRAM (Protected RAM - unchanged by reset)
6212	0x00FF FFFF	[End of RAM]
6213
6214
6215System Initialization:
6216----------------------
6217
6218In the reset configuration, U-Boot starts at the reset entry point
6219(on most PowerPC systems at address 0x00000100). Because of the reset
6220configuration for CS0# this is a mirror of the on board Flash memory.
6221To be able to re-map memory U-Boot then jumps to its link address.
6222To be able to implement the initialization code in C, a (small!)
6223initial stack is set up in the internal Dual Ported RAM (in case CPUs
6224which provide such a feature like MPC8xx or MPC8260), or in a locked
6225part of the data cache. After that, U-Boot initializes the CPU core,
6226the caches and the SIU.
6227
6228Next, all (potentially) available memory banks are mapped using a
6229preliminary mapping. For example, we put them on 512 MB boundaries
6230(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6231on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6232programmed for SDRAM access. Using the temporary configuration, a
6233simple memory test is run that determines the size of the SDRAM
6234banks.
6235
6236When there is more than one SDRAM bank, and the banks are of
6237different size, the largest is mapped first. For equal size, the first
6238bank (CS2#) is mapped first. The first mapping is always for address
62390x00000000, with any additional banks following immediately to create
6240contiguous memory starting from 0.
6241
6242Then, the monitor installs itself at the upper end of the SDRAM area
6243and allocates memory for use by malloc() and for the global Board
6244Info data; also, the exception vector code is copied to the low RAM
6245pages, and the final stack is set up.
6246
6247Only after this relocation will you have a "normal" C environment;
6248until that you are restricted in several ways, mostly because you are
6249running from ROM, and because the code will have to be relocated to a
6250new address in RAM.
6251
6252
6253U-Boot Porting Guide:
6254----------------------
6255
6256[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6257list, October 2002]
6258
6259
6260int main(int argc, char *argv[])
6261{
6262	sighandler_t no_more_time;
6263
6264	signal(SIGALRM, no_more_time);
6265	alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6266
6267	if (available_money > available_manpower) {
6268		Pay consultant to port U-Boot;
6269		return 0;
6270	}
6271
6272	Download latest U-Boot source;
6273
6274	Subscribe to u-boot mailing list;
6275
6276	if (clueless)
6277		email("Hi, I am new to U-Boot, how do I get started?");
6278
6279	while (learning) {
6280		Read the README file in the top level directory;
6281		Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6282		Read applicable doc/*.README;
6283		Read the source, Luke;
6284		/* find . -name "*.[chS]" | xargs grep -i <keyword> */
6285	}
6286
6287	if (available_money > toLocalCurrency ($2500))
6288		Buy a BDI3000;
6289	else
6290		Add a lot of aggravation and time;
6291
6292	if (a similar board exists) {	/* hopefully... */
6293		cp -a board/<similar> board/<myboard>
6294		cp include/configs/<similar>.h include/configs/<myboard>.h
6295	} else {
6296		Create your own board support subdirectory;
6297		Create your own board include/configs/<myboard>.h file;
6298	}
6299	Edit new board/<myboard> files
6300	Edit new include/configs/<myboard>.h
6301
6302	while (!accepted) {
6303		while (!running) {
6304			do {
6305				Add / modify source code;
6306			} until (compiles);
6307			Debug;
6308			if (clueless)
6309				email("Hi, I am having problems...");
6310		}
6311		Send patch file to the U-Boot email list;
6312		if (reasonable critiques)
6313			Incorporate improvements from email list code review;
6314		else
6315			Defend code as written;
6316	}
6317
6318	return 0;
6319}
6320
6321void no_more_time (int sig)
6322{
6323      hire_a_guru();
6324}
6325
6326
6327Coding Standards:
6328-----------------
6329
6330All contributions to U-Boot should conform to the Linux kernel
6331coding style; see the file "Documentation/CodingStyle" and the script
6332"scripts/Lindent" in your Linux kernel source directory.
6333
6334Source files originating from a different project (for example the
6335MTD subsystem) are generally exempt from these guidelines and are not
6336reformatted to ease subsequent migration to newer versions of those
6337sources.
6338
6339Please note that U-Boot is implemented in C (and to some small parts in
6340Assembler); no C++ is used, so please do not use C++ style comments (//)
6341in your code.
6342
6343Please also stick to the following formatting rules:
6344- remove any trailing white space
6345- use TAB characters for indentation and vertical alignment, not spaces
6346- make sure NOT to use DOS '\r\n' line feeds
6347- do not add more than 2 consecutive empty lines to source files
6348- do not add trailing empty lines to source files
6349
6350Submissions which do not conform to the standards may be returned
6351with a request to reformat the changes.
6352
6353
6354Submitting Patches:
6355-------------------
6356
6357Since the number of patches for U-Boot is growing, we need to
6358establish some rules. Submissions which do not conform to these rules
6359may be rejected, even when they contain important and valuable stuff.
6360
6361Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6362
6363Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6364see http://lists.denx.de/mailman/listinfo/u-boot
6365
6366When you send a patch, please include the following information with
6367it:
6368
6369* For bug fixes: a description of the bug and how your patch fixes
6370  this bug. Please try to include a way of demonstrating that the
6371  patch actually fixes something.
6372
6373* For new features: a description of the feature and your
6374  implementation.
6375
6376* A CHANGELOG entry as plaintext (separate from the patch)
6377
6378* For major contributions, add a MAINTAINERS file with your
6379  information and associated file and directory references.
6380
6381* When you add support for a new board, don't forget to add a
6382  maintainer e-mail address to the boards.cfg file, too.
6383
6384* If your patch adds new configuration options, don't forget to
6385  document these in the README file.
6386
6387* The patch itself. If you are using git (which is *strongly*
6388  recommended) you can easily generate the patch using the
6389  "git format-patch". If you then use "git send-email" to send it to
6390  the U-Boot mailing list, you will avoid most of the common problems
6391  with some other mail clients.
6392
6393  If you cannot use git, use "diff -purN OLD NEW". If your version of
6394  diff does not support these options, then get the latest version of
6395  GNU diff.
6396
6397  The current directory when running this command shall be the parent
6398  directory of the U-Boot source tree (i. e. please make sure that
6399  your patch includes sufficient directory information for the
6400  affected files).
6401
6402  We prefer patches as plain text. MIME attachments are discouraged,
6403  and compressed attachments must not be used.
6404
6405* If one logical set of modifications affects or creates several
6406  files, all these changes shall be submitted in a SINGLE patch file.
6407
6408* Changesets that contain different, unrelated modifications shall be
6409  submitted as SEPARATE patches, one patch per changeset.
6410
6411
6412Notes:
6413
6414* Before sending the patch, run the buildman script on your patched
6415  source tree and make sure that no errors or warnings are reported
6416  for any of the boards.
6417
6418* Keep your modifications to the necessary minimum: A patch
6419  containing several unrelated changes or arbitrary reformats will be
6420  returned with a request to re-formatting / split it.
6421
6422* If you modify existing code, make sure that your new code does not
6423  add to the memory footprint of the code ;-) Small is beautiful!
6424  When adding new features, these should compile conditionally only
6425  (using #ifdef), and the resulting code with the new feature
6426  disabled must not need more memory than the old code without your
6427  modification.
6428
6429* Remember that there is a size limit of 100 kB per message on the
6430  u-boot mailing list. Bigger patches will be moderated. If they are
6431  reasonable and not too big, they will be acknowledged. But patches
6432  bigger than the size limit should be avoided.
6433