xref: /rk3399_rockchip-uboot/README (revision 1668d64439ecf4af64d5de2e24bb3d7c4e643b25)
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 and CREDITS files to find out
38who contributed the specific port. The boards.cfg file lists board
39maintainers.
40
41Note: There is no CHANGELOG file in the actual U-Boot source tree;
42it can be created dynamically from the Git log using:
43
44	make CHANGELOG
45
46
47Where to get help:
48==================
49
50In case you have questions about, problems with or contributions for
51U-Boot you should send a message to the U-Boot mailing list at
52<u-boot@lists.denx.de>. There is also an archive of previous traffic
53on the mailing list - please search the archive before asking FAQ's.
54Please see http://lists.denx.de/pipermail/u-boot and
55http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
56
57
58Where to get source code:
59=========================
60
61The U-Boot source code is maintained in the git repository at
62git://www.denx.de/git/u-boot.git ; you can browse it online at
63http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
64
65The "snapshot" links on this page allow you to download tarballs of
66any version you might be interested in. Official releases are also
67available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
68directory.
69
70Pre-built (and tested) images are available from
71ftp://ftp.denx.de/pub/u-boot/images/
72
73
74Where we come from:
75===================
76
77- start from 8xxrom sources
78- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
79- clean up code
80- make it easier to add custom boards
81- make it possible to add other [PowerPC] CPUs
82- extend functions, especially:
83  * Provide extended interface to Linux boot loader
84  * S-Record download
85  * network boot
86  * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87- create ARMBoot project (http://sourceforge.net/projects/armboot)
88- add other CPU families (starting with ARM)
89- create U-Boot project (http://sourceforge.net/projects/u-boot)
90- current project page: see http://www.denx.de/wiki/U-Boot
91
92
93Names and Spelling:
94===================
95
96The "official" name of this project is "Das U-Boot". The spelling
97"U-Boot" shall be used in all written text (documentation, comments
98in source files etc.). Example:
99
100	This is the README file for the U-Boot project.
101
102File names etc. shall be based on the string "u-boot". Examples:
103
104	include/asm-ppc/u-boot.h
105
106	#include <asm/u-boot.h>
107
108Variable names, preprocessor constants etc. shall be either based on
109the string "u_boot" or on "U_BOOT". Example:
110
111	U_BOOT_VERSION		u_boot_logo
112	IH_OS_U_BOOT		u_boot_hush_start
113
114
115Versioning:
116===========
117
118Starting with the release in October 2008, the names of the releases
119were changed from numerical release numbers without deeper meaning
120into a time stamp based numbering. Regular releases are identified by
121names consisting of the calendar year and month of the release date.
122Additional fields (if present) indicate release candidates or bug fix
123releases in "stable" maintenance trees.
124
125Examples:
126	U-Boot v2009.11	    - Release November 2009
127	U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
128	U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
129
130
131Directory Hierarchy:
132====================
133
134/arch			Architecture specific files
135  /arc			Files generic to ARC architecture
136    /cpu		CPU specific files
137      /arc700		Files specific to ARC 700 CPUs
138    /lib		Architecture specific library files
139  /arm			Files generic to ARM architecture
140    /cpu		CPU specific files
141      /arm720t		Files specific to ARM 720 CPUs
142      /arm920t		Files specific to ARM 920 CPUs
143	/at91		Files specific to Atmel AT91RM9200 CPU
144	/imx		Files specific to Freescale MC9328 i.MX CPUs
145	/s3c24x0	Files specific to Samsung S3C24X0 CPUs
146      /arm926ejs	Files specific to ARM 926 CPUs
147      /arm1136		Files specific to ARM 1136 CPUs
148      /pxa		Files specific to Intel XScale PXA CPUs
149      /sa1100		Files specific to Intel StrongARM SA1100 CPUs
150    /lib		Architecture specific library files
151  /avr32		Files generic to AVR32 architecture
152    /cpu		CPU specific files
153    /lib		Architecture specific library files
154  /blackfin		Files generic to Analog Devices Blackfin architecture
155    /cpu		CPU specific files
156    /lib		Architecture specific library files
157  /m68k			Files generic to m68k architecture
158    /cpu		CPU specific files
159      /mcf52x2		Files specific to Freescale ColdFire MCF52x2 CPUs
160      /mcf5227x		Files specific to Freescale ColdFire MCF5227x CPUs
161      /mcf532x		Files specific to Freescale ColdFire MCF5329 CPUs
162      /mcf5445x		Files specific to Freescale ColdFire MCF5445x CPUs
163      /mcf547x_8x	Files specific to Freescale ColdFire MCF547x_8x CPUs
164    /lib		Architecture specific library files
165  /microblaze		Files generic to microblaze architecture
166    /cpu		CPU specific files
167    /lib		Architecture specific library files
168  /mips			Files generic to MIPS architecture
169    /cpu		CPU specific files
170      /mips32		Files specific to MIPS32 CPUs
171      /mips64		Files specific to MIPS64 CPUs
172    /lib		Architecture specific library files
173  /nds32		Files generic to NDS32 architecture
174    /cpu		CPU specific files
175      /n1213		Files specific to Andes Technology N1213 CPUs
176    /lib		Architecture specific library files
177  /nios2		Files generic to Altera NIOS2 architecture
178    /cpu		CPU specific files
179    /lib		Architecture specific library files
180  /openrisc		Files generic to OpenRISC architecture
181    /cpu		CPU specific files
182    /lib		Architecture specific library files
183  /powerpc		Files generic to PowerPC architecture
184    /cpu		CPU specific files
185      /74xx_7xx		Files specific to Freescale MPC74xx and 7xx CPUs
186      /mpc5xx		Files specific to Freescale MPC5xx CPUs
187      /mpc5xxx		Files specific to Freescale MPC5xxx CPUs
188      /mpc8xx		Files specific to Freescale MPC8xx CPUs
189      /mpc824x		Files specific to Freescale MPC824x CPUs
190      /mpc8260		Files specific to Freescale MPC8260 CPUs
191      /mpc85xx		Files specific to Freescale MPC85xx CPUs
192      /ppc4xx		Files specific to AMCC PowerPC 4xx CPUs
193    /lib		Architecture specific library files
194  /sh			Files generic to SH architecture
195    /cpu		CPU specific files
196      /sh2		Files specific to sh2 CPUs
197      /sh3		Files specific to sh3 CPUs
198      /sh4		Files specific to sh4 CPUs
199    /lib		Architecture specific library files
200  /sparc		Files generic to SPARC architecture
201    /cpu		CPU specific files
202      /leon2		Files specific to Gaisler LEON2 SPARC CPU
203      /leon3		Files specific to Gaisler LEON3 SPARC CPU
204    /lib		Architecture specific library files
205  /x86			Files generic to x86 architecture
206    /cpu		CPU specific files
207    /lib		Architecture specific library files
208/api			Machine/arch independent API for external apps
209/board			Board dependent files
210/common			Misc architecture independent functions
211/disk			Code for disk drive partition handling
212/doc			Documentation (don't expect too much)
213/drivers		Commonly used device drivers
214/dts			Contains Makefile for building internal U-Boot fdt.
215/examples		Example code for standalone applications, etc.
216/fs			Filesystem code (cramfs, ext2, jffs2, etc.)
217/include		Header Files
218/lib			Files generic to all architectures
219  /libfdt		Library files to support flattened device trees
220  /lzma			Library files to support LZMA decompression
221  /lzo			Library files to support LZO decompression
222/net			Networking code
223/post			Power On Self Test
224/spl			Secondary Program Loader framework
225/tools			Tools to build S-Record or U-Boot images, etc.
226
227Software Configuration:
228=======================
229
230Configuration is usually done using C preprocessor defines; the
231rationale behind that is to avoid dead code whenever possible.
232
233There are two classes of configuration variables:
234
235* Configuration _OPTIONS_:
236  These are selectable by the user and have names beginning with
237  "CONFIG_".
238
239* Configuration _SETTINGS_:
240  These depend on the hardware etc. and should not be meddled with if
241  you don't know what you're doing; they have names beginning with
242  "CONFIG_SYS_".
243
244Later we will add a configuration tool - probably similar to or even
245identical to what's used for the Linux kernel. Right now, we have to
246do the configuration by hand, which means creating some symbolic
247links and editing some configuration files. We use the TQM8xxL boards
248as an example here.
249
250
251Selection of Processor Architecture and Board Type:
252---------------------------------------------------
253
254For all supported boards there are ready-to-use default
255configurations available; just type "make <board_name>_defconfig".
256
257Example: For a TQM823L module type:
258
259	cd u-boot
260	make TQM823L_defconfig
261
262For the Cogent platform, you need to specify the CPU type as well;
263e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
264directory according to the instructions in cogent/README.
265
266
267Sandbox Environment:
268--------------------
269
270U-Boot can be built natively to run on a Linux host using the 'sandbox'
271board. This allows feature development which is not board- or architecture-
272specific to be undertaken on a native platform. The sandbox is also used to
273run some of U-Boot's tests.
274
275See board/sandbox/sandbox/README.sandbox for more details.
276
277
278Configuration Options:
279----------------------
280
281Configuration depends on the combination of board and CPU type; all
282such information is kept in a configuration file
283"include/configs/<board_name>.h".
284
285Example: For a TQM823L module, all configuration settings are in
286"include/configs/TQM823L.h".
287
288
289Many of the options are named exactly as the corresponding Linux
290kernel configuration options. The intention is to make it easier to
291build a config tool - later.
292
293
294The following options need to be configured:
295
296- CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.
297
298- Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.
299
300- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301		Define exactly one, e.g. CONFIG_ATSTK1002
302
303- CPU Module Type: (if CONFIG_COGENT is defined)
304		Define exactly one of
305		CONFIG_CMA286_60_OLD
306--- FIXME --- not tested yet:
307		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308		CONFIG_CMA287_23, CONFIG_CMA287_50
309
310- Motherboard Type: (if CONFIG_COGENT is defined)
311		Define exactly one of
312		CONFIG_CMA101, CONFIG_CMA102
313
314- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315		Define one or more of
316		CONFIG_CMA302
317
318- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319		Define one or more of
320		CONFIG_LCD_HEARTBEAT	- update a character position on
321					  the LCD display every second with
322					  a "rotator" |\-/|\-/
323
324- Marvell Family Member
325		CONFIG_SYS_MVFS		- define it if you want to enable
326					  multiple fs option at one time
327					  for marvell soc family
328
329- MPC824X Family Member (if CONFIG_MPC824X is defined)
330		Define exactly one of
331		CONFIG_MPC8240, CONFIG_MPC8245
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		requred during NOR boot.
411
412		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
413
414		This is the value to write into CCSR offset 0x18600
415		according to the A004510 workaround.
416
417		CONFIG_SYS_FSL_DSP_DDR_ADDR
418		This value denotes start offset of DDR memory which is
419		connected exclusively to the DSP cores.
420
421		CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
422		This value denotes start offset of M2 memory
423		which is directly connected to the DSP core.
424
425		CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
426		This value denotes start offset of M3 memory which is directly
427		connected to the DSP core.
428
429		CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430		This value denotes start offset of DSP CCSR space.
431
432		CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
433		Single Source Clock is clocking mode present in some of FSL SoC's.
434		In this mode, a single differential clock is used to supply
435		clocks to the sysclock, ddrclock and usbclock.
436
437		CONFIG_SYS_CPC_REINIT_F
438		This CONFIG is defined when the CPC is configured as SRAM at the
439		time of U-boot entry and is required to be re-initialized.
440
441		CONFIG_DEEP_SLEEP
442		Inidcates this SoC supports deep sleep feature. If deep sleep is
443		supported, core will start to execute uboot when wakes up.
444
445- Generic CPU options:
446		CONFIG_SYS_GENERIC_GLOBAL_DATA
447		Defines global data is initialized in generic board board_init_f().
448		If this macro is defined, global data is created and cleared in
449		generic board board_init_f(). Without this macro, architecture/board
450		should initialize global data before calling board_init_f().
451
452		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
453
454		Defines the endianess of the CPU. Implementation of those
455		values is arch specific.
456
457		CONFIG_SYS_FSL_DDR
458		Freescale DDR driver in use. This type of DDR controller is
459		found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
460		SoCs.
461
462		CONFIG_SYS_FSL_DDR_ADDR
463		Freescale DDR memory-mapped register base.
464
465		CONFIG_SYS_FSL_DDR_EMU
466		Specify emulator support for DDR. Some DDR features such as
467		deskew training are not available.
468
469		CONFIG_SYS_FSL_DDRC_GEN1
470		Freescale DDR1 controller.
471
472		CONFIG_SYS_FSL_DDRC_GEN2
473		Freescale DDR2 controller.
474
475		CONFIG_SYS_FSL_DDRC_GEN3
476		Freescale DDR3 controller.
477
478		CONFIG_SYS_FSL_DDRC_GEN4
479		Freescale DDR4 controller.
480
481		CONFIG_SYS_FSL_DDRC_ARM_GEN3
482		Freescale DDR3 controller for ARM-based SoCs.
483
484		CONFIG_SYS_FSL_DDR1
485		Board config to use DDR1. It can be enabled for SoCs with
486		Freescale DDR1 or DDR2 controllers, depending on the board
487		implemetation.
488
489		CONFIG_SYS_FSL_DDR2
490		Board config to use DDR2. It can be eanbeld for SoCs with
491		Freescale DDR2 or DDR3 controllers, depending on the board
492		implementation.
493
494		CONFIG_SYS_FSL_DDR3
495		Board config to use DDR3. It can be enabled for SoCs with
496		Freescale DDR3 or DDR3L controllers.
497
498		CONFIG_SYS_FSL_DDR3L
499		Board config to use DDR3L. It can be enabled for SoCs with
500		DDR3L controllers.
501
502		CONFIG_SYS_FSL_DDR4
503		Board config to use DDR4. It can be enabled for SoCs with
504		DDR4 controllers.
505
506		CONFIG_SYS_FSL_IFC_BE
507		Defines the IFC controller register space as Big Endian
508
509		CONFIG_SYS_FSL_IFC_LE
510		Defines the IFC controller register space as Little Endian
511
512		CONFIG_SYS_FSL_PBL_PBI
513		It enables addition of RCW (Power on reset configuration) in built image.
514		Please refer doc/README.pblimage for more details
515
516		CONFIG_SYS_FSL_PBL_RCW
517		It adds PBI(pre-boot instructions) commands in u-boot build image.
518		PBI commands can be used to configure SoC before it starts the execution.
519		Please refer doc/README.pblimage for more details
520
521		CONFIG_SPL_FSL_PBL
522		It adds a target to create boot binary having SPL binary in PBI format
523		concatenated with u-boot binary.
524
525		CONFIG_SYS_FSL_DDR_BE
526		Defines the DDR controller register space as Big Endian
527
528		CONFIG_SYS_FSL_DDR_LE
529		Defines the DDR controller register space as Little Endian
530
531		CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532		Physical address from the view of DDR controllers. It is the
533		same as CONFIG_SYS_DDR_SDRAM_BASE for  all Power SoCs. But
534		it could be different for ARM SoCs.
535
536		CONFIG_SYS_FSL_DDR_INTLV_256B
537		DDR controller interleaving on 256-byte. This is a special
538		interleaving mode, handled by Dickens for Freescale layerscape
539		SoCs with ARM core.
540
541- Intel Monahans options:
542		CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
543
544		Defines the Monahans run mode to oscillator
545		ratio. Valid values are 8, 16, 24, 31. The core
546		frequency is this value multiplied by 13 MHz.
547
548		CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
549
550		Defines the Monahans turbo mode to oscillator
551		ratio. Valid values are 1 (default if undefined) and
552		2. The core frequency as calculated above is multiplied
553		by this value.
554
555- MIPS CPU options:
556		CONFIG_SYS_INIT_SP_OFFSET
557
558		Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559		pointer. This is needed for the temporary stack before
560		relocation.
561
562		CONFIG_SYS_MIPS_CACHE_MODE
563
564		Cache operation mode for the MIPS CPU.
565		See also arch/mips/include/asm/mipsregs.h.
566		Possible values are:
567			CONF_CM_CACHABLE_NO_WA
568			CONF_CM_CACHABLE_WA
569			CONF_CM_UNCACHED
570			CONF_CM_CACHABLE_NONCOHERENT
571			CONF_CM_CACHABLE_CE
572			CONF_CM_CACHABLE_COW
573			CONF_CM_CACHABLE_CUW
574			CONF_CM_CACHABLE_ACCELERATED
575
576		CONFIG_SYS_XWAY_EBU_BOOTCFG
577
578		Special option for Lantiq XWAY SoCs for booting from NOR flash.
579		See also arch/mips/cpu/mips32/start.S.
580
581		CONFIG_XWAY_SWAP_BYTES
582
583		Enable compilation of tools/xway-swap-bytes needed for Lantiq
584		XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585		be swapped if a flash programmer is used.
586
587- ARM options:
588		CONFIG_SYS_EXCEPTION_VECTORS_HIGH
589
590		Select high exception vectors of the ARM core, e.g., do not
591		clear the V bit of the c1 register of CP15.
592
593		CONFIG_SYS_THUMB_BUILD
594
595		Use this flag to build U-Boot using the Thumb instruction
596		set for ARM architectures. Thumb instruction set provides
597		better code density. For ARM architectures that support
598		Thumb2 this flag will result in Thumb2 code generated by
599		GCC.
600
601		CONFIG_ARM_ERRATA_716044
602		CONFIG_ARM_ERRATA_742230
603		CONFIG_ARM_ERRATA_743622
604		CONFIG_ARM_ERRATA_751472
605		CONFIG_ARM_ERRATA_794072
606		CONFIG_ARM_ERRATA_761320
607
608		If set, the workarounds for these ARM errata are applied early
609		during U-Boot startup. Note that these options force the
610		workarounds to be applied; no CPU-type/version detection
611		exists, unlike the similar options in the Linux kernel. Do not
612		set these options unless they apply!
613
614- CPU timer options:
615		CONFIG_SYS_HZ
616
617		The frequency of the timer returned by get_timer().
618		get_timer() must operate in milliseconds and this CONFIG
619		option must be set to 1000.
620
621- Linux Kernel Interface:
622		CONFIG_CLOCKS_IN_MHZ
623
624		U-Boot stores all clock information in Hz
625		internally. For binary compatibility with older Linux
626		kernels (which expect the clocks passed in the
627		bd_info data to be in MHz) the environment variable
628		"clocks_in_mhz" can be defined so that U-Boot
629		converts clock data to MHZ before passing it to the
630		Linux kernel.
631		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
632		"clocks_in_mhz=1" is automatically included in the
633		default environment.
634
635		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]
636
637		When transferring memsize parameter to linux, some versions
638		expect it to be in bytes, others in MB.
639		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
640
641		CONFIG_OF_LIBFDT
642
643		New kernel versions are expecting firmware settings to be
644		passed using flattened device trees (based on open firmware
645		concepts).
646
647		CONFIG_OF_LIBFDT
648		 * New libfdt-based support
649		 * Adds the "fdt" command
650		 * The bootm command automatically updates the fdt
651
652		OF_CPU - The proper name of the cpus node (only required for
653			MPC512X and MPC5xxx based boards).
654		OF_SOC - The proper name of the soc node (only required for
655			MPC512X and MPC5xxx based boards).
656		OF_TBCLK - The timebase frequency.
657		OF_STDOUT_PATH - The path to the console device
658
659		boards with QUICC Engines require OF_QE to set UCC MAC
660		addresses
661
662		CONFIG_OF_BOARD_SETUP
663
664		Board code has addition modification that it wants to make
665		to the flat device tree before handing it off to the kernel
666
667		CONFIG_OF_BOOT_CPU
668
669		This define fills in the correct boot CPU in the boot
670		param header, the default value is zero if undefined.
671
672		CONFIG_OF_IDE_FIXUP
673
674		U-Boot can detect if an IDE device is present or not.
675		If not, and this new config option is activated, U-Boot
676		removes the ATA node from the DTS before booting Linux,
677		so the Linux IDE driver does not probe the device and
678		crash. This is needed for buggy hardware (uc101) where
679		no pull down resistor is connected to the signal IDE5V_DD7.
680
681		CONFIG_MACH_TYPE	[relevant for ARM only][mandatory]
682
683		This setting is mandatory for all boards that have only one
684		machine type and must be used to specify the machine type
685		number as it appears in the ARM machine registry
686		(see http://www.arm.linux.org.uk/developer/machines/).
687		Only boards that have multiple machine types supported
688		in a single configuration file and the machine type is
689		runtime discoverable, do not have to use this setting.
690
691- vxWorks boot parameters:
692
693		bootvx constructs a valid bootline using the following
694		environments variables: bootfile, ipaddr, serverip, hostname.
695		It loads the vxWorks image pointed bootfile.
696
697		CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
698		CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
699		CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
700		CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
701
702		CONFIG_SYS_VXWORKS_ADD_PARAMS
703
704		Add it at the end of the bootline. E.g "u=username pw=secret"
705
706		Note: If a "bootargs" environment is defined, it will overwride
707		the defaults discussed just above.
708
709- Cache Configuration:
710		CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
711		CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
712		CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
713
714- Cache Configuration for ARM:
715		CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
716				      controller
717		CONFIG_SYS_PL310_BASE - Physical base address of PL310
718					controller register space
719
720- Serial Ports:
721		CONFIG_PL010_SERIAL
722
723		Define this if you want support for Amba PrimeCell PL010 UARTs.
724
725		CONFIG_PL011_SERIAL
726
727		Define this if you want support for Amba PrimeCell PL011 UARTs.
728
729		CONFIG_PL011_CLOCK
730
731		If you have Amba PrimeCell PL011 UARTs, set this variable to
732		the clock speed of the UARTs.
733
734		CONFIG_PL01x_PORTS
735
736		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
737		define this to a list of base addresses for each (supported)
738		port. See e.g. include/configs/versatile.h
739
740		CONFIG_PL011_SERIAL_RLCR
741
742		Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
743		have separate receive and transmit line control registers.  Set
744		this variable to initialize the extra register.
745
746		CONFIG_PL011_SERIAL_FLUSH_ON_INIT
747
748		On some platforms (e.g. U8500) U-Boot is loaded by a second stage
749		boot loader that has already initialized the UART.  Define this
750		variable to flush the UART at init time.
751
752		CONFIG_SERIAL_HW_FLOW_CONTROL
753
754		Define this variable to enable hw flow control in serial driver.
755		Current user of this option is drivers/serial/nsl16550.c driver
756
757- Console Interface:
758		Depending on board, define exactly one serial port
759		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
760		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
761		console by defining CONFIG_8xx_CONS_NONE
762
763		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
764		port routines must be defined elsewhere
765		(i.e. serial_init(), serial_getc(), ...)
766
767		CONFIG_CFB_CONSOLE
768		Enables console device for a color framebuffer. Needs following
769		defines (cf. smiLynxEM, i8042)
770			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
771						(default big endian)
772			VIDEO_HW_RECTFILL	graphic chip supports
773						rectangle fill
774						(cf. smiLynxEM)
775			VIDEO_HW_BITBLT		graphic chip supports
776						bit-blit (cf. smiLynxEM)
777			VIDEO_VISIBLE_COLS	visible pixel columns
778						(cols=pitch)
779			VIDEO_VISIBLE_ROWS	visible pixel rows
780			VIDEO_PIXEL_SIZE	bytes per pixel
781			VIDEO_DATA_FORMAT	graphic data format
782						(0-5, cf. cfb_console.c)
783			VIDEO_FB_ADRS		framebuffer address
784			VIDEO_KBD_INIT_FCT	keyboard int fct
785						(i.e. i8042_kbd_init())
786			VIDEO_TSTC_FCT		test char fct
787						(i.e. i8042_tstc)
788			VIDEO_GETC_FCT		get char fct
789						(i.e. i8042_getc)
790			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
791						(requires blink timer
792						cf. i8042.c)
793			CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
794			CONFIG_CONSOLE_TIME	display time/date info in
795						upper right corner
796						(requires CONFIG_CMD_DATE)
797			CONFIG_VIDEO_LOGO	display Linux logo in
798						upper left corner
799			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
800						linux_logo.h for logo.
801						Requires CONFIG_VIDEO_LOGO
802			CONFIG_CONSOLE_EXTRA_INFO
803						additional board info beside
804						the logo
805
806		When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
807		a limited number of ANSI escape sequences (cursor control,
808		erase functions and limited graphics rendition control).
809
810		When CONFIG_CFB_CONSOLE is defined, video console is
811		default i/o. Serial console can be forced with
812		environment 'console=serial'.
813
814		When CONFIG_SILENT_CONSOLE is defined, all console
815		messages (by U-Boot and Linux!) can be silenced with
816		the "silent" environment variable. See
817		doc/README.silent for more information.
818
819		CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
820			is 0x00.
821		CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
822			is 0xa0.
823
824- Console Baudrate:
825		CONFIG_BAUDRATE - in bps
826		Select one of the baudrates listed in
827		CONFIG_SYS_BAUDRATE_TABLE, see below.
828		CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
829
830- Console Rx buffer length
831		With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
832		the maximum receive buffer length for the SMC.
833		This option is actual only for 82xx and 8xx possible.
834		If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
835		must be defined, to setup the maximum idle timeout for
836		the SMC.
837
838- Pre-Console Buffer:
839		Prior to the console being initialised (i.e. serial UART
840		initialised etc) all console output is silently discarded.
841		Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
842		buffer any console messages prior to the console being
843		initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
844		bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
845		a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
846		bytes are output before the console is initialised, the
847		earlier bytes are discarded.
848
849		'Sane' compilers will generate smaller code if
850		CONFIG_PRE_CON_BUF_SZ is a power of 2
851
852- Safe printf() functions
853		Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
854		the printf() functions. These are defined in
855		include/vsprintf.h and include snprintf(), vsnprintf() and
856		so on. Code size increase is approximately 300-500 bytes.
857		If this option is not given then these functions will
858		silently discard their buffer size argument - this means
859		you are not getting any overflow checking in this case.
860
861- Boot Delay:	CONFIG_BOOTDELAY - in seconds
862		Delay before automatically booting the default image;
863		set to -1 to disable autoboot.
864		set to -2 to autoboot with no delay and not check for abort
865		(even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
866
867		See doc/README.autoboot for these options that
868		work with CONFIG_BOOTDELAY. None are required.
869		CONFIG_BOOT_RETRY_TIME
870		CONFIG_BOOT_RETRY_MIN
871		CONFIG_AUTOBOOT_KEYED
872		CONFIG_AUTOBOOT_PROMPT
873		CONFIG_AUTOBOOT_DELAY_STR
874		CONFIG_AUTOBOOT_STOP_STR
875		CONFIG_AUTOBOOT_DELAY_STR2
876		CONFIG_AUTOBOOT_STOP_STR2
877		CONFIG_ZERO_BOOTDELAY_CHECK
878		CONFIG_RESET_TO_RETRY
879
880- Autoboot Command:
881		CONFIG_BOOTCOMMAND
882		Only needed when CONFIG_BOOTDELAY is enabled;
883		define a command string that is automatically executed
884		when no character is read on the console interface
885		within "Boot Delay" after reset.
886
887		CONFIG_BOOTARGS
888		This can be used to pass arguments to the bootm
889		command. The value of CONFIG_BOOTARGS goes into the
890		environment value "bootargs".
891
892		CONFIG_RAMBOOT and CONFIG_NFSBOOT
893		The value of these goes into the environment as
894		"ramboot" and "nfsboot" respectively, and can be used
895		as a convenience, when switching between booting from
896		RAM and NFS.
897
898- Bootcount:
899		CONFIG_BOOTCOUNT_LIMIT
900		Implements a mechanism for detecting a repeating reboot
901		cycle, see:
902		http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
903
904		CONFIG_BOOTCOUNT_ENV
905		If no softreset save registers are found on the hardware
906		"bootcount" is stored in the environment. To prevent a
907		saveenv on all reboots, the environment variable
908		"upgrade_available" is used. If "upgrade_available" is
909		0, "bootcount" is always 0, if "upgrade_available" is
910		1 "bootcount" is incremented in the environment.
911		So the Userspace Applikation must set the "upgrade_available"
912		and "bootcount" variable to 0, if a boot was successfully.
913
914- Pre-Boot Commands:
915		CONFIG_PREBOOT
916
917		When this option is #defined, the existence of the
918		environment variable "preboot" will be checked
919		immediately before starting the CONFIG_BOOTDELAY
920		countdown and/or running the auto-boot command resp.
921		entering interactive mode.
922
923		This feature is especially useful when "preboot" is
924		automatically generated or modified. For an example
925		see the LWMON board specific code: here "preboot" is
926		modified when the user holds down a certain
927		combination of keys on the (special) keyboard when
928		booting the systems
929
930- Serial Download Echo Mode:
931		CONFIG_LOADS_ECHO
932		If defined to 1, all characters received during a
933		serial download (using the "loads" command) are
934		echoed back. This might be needed by some terminal
935		emulations (like "cu"), but may as well just take
936		time on others. This setting #define's the initial
937		value of the "loads_echo" environment variable.
938
939- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
940		CONFIG_KGDB_BAUDRATE
941		Select one of the baudrates listed in
942		CONFIG_SYS_BAUDRATE_TABLE, see below.
943
944- Monitor Functions:
945		Monitor commands can be included or excluded
946		from the build by using the #include files
947		<config_cmd_all.h> and #undef'ing unwanted
948		commands, or using <config_cmd_default.h>
949		and augmenting with additional #define's
950		for wanted commands.
951
952		The default command configuration includes all commands
953		except those marked below with a "*".
954
955		CONFIG_CMD_AES		  AES 128 CBC encrypt/decrypt
956		CONFIG_CMD_ASKENV	* ask for env variable
957		CONFIG_CMD_BDI		  bdinfo
958		CONFIG_CMD_BEDBUG	* Include BedBug Debugger
959		CONFIG_CMD_BMP		* BMP support
960		CONFIG_CMD_BSP		* Board specific commands
961		CONFIG_CMD_BOOTD	  bootd
962		CONFIG_CMD_CACHE	* icache, dcache
963		CONFIG_CMD_CLK   	* clock command support
964		CONFIG_CMD_CONSOLE	  coninfo
965		CONFIG_CMD_CRC32	* crc32
966		CONFIG_CMD_DATE		* support for RTC, date/time...
967		CONFIG_CMD_DHCP		* DHCP support
968		CONFIG_CMD_DIAG		* Diagnostics
969		CONFIG_CMD_DS4510	* ds4510 I2C gpio commands
970		CONFIG_CMD_DS4510_INFO	* ds4510 I2C info command
971		CONFIG_CMD_DS4510_MEM	* ds4510 I2C eeprom/sram commansd
972		CONFIG_CMD_DS4510_RST	* ds4510 I2C rst command
973		CONFIG_CMD_DTT		* Digital Therm and Thermostat
974		CONFIG_CMD_ECHO		  echo arguments
975		CONFIG_CMD_EDITENV	  edit env variable
976		CONFIG_CMD_EEPROM	* EEPROM read/write support
977		CONFIG_CMD_ELF		* bootelf, bootvx
978		CONFIG_CMD_ENV_CALLBACK	* display details about env callbacks
979		CONFIG_CMD_ENV_FLAGS	* display details about env flags
980		CONFIG_CMD_ENV_EXISTS	* check existence of env variable
981		CONFIG_CMD_EXPORTENV	* export the environment
982		CONFIG_CMD_EXT2		* ext2 command support
983		CONFIG_CMD_EXT4		* ext4 command support
984		CONFIG_CMD_FS_GENERIC	* filesystem commands (e.g. load, ls)
985					  that work for multiple fs types
986		CONFIG_CMD_SAVEENV	  saveenv
987		CONFIG_CMD_FDC		* Floppy Disk Support
988		CONFIG_CMD_FAT		* FAT command support
989		CONFIG_CMD_FLASH	  flinfo, erase, protect
990		CONFIG_CMD_FPGA		  FPGA device initialization support
991		CONFIG_CMD_FUSE		* Device fuse support
992		CONFIG_CMD_GETTIME	* Get time since boot
993		CONFIG_CMD_GO		* the 'go' command (exec code)
994		CONFIG_CMD_GREPENV	* search environment
995		CONFIG_CMD_HASH		* calculate hash / digest
996		CONFIG_CMD_HWFLOW	* RTS/CTS hw flow control
997		CONFIG_CMD_I2C		* I2C serial bus support
998		CONFIG_CMD_IDE		* IDE harddisk support
999		CONFIG_CMD_IMI		  iminfo
1000		CONFIG_CMD_IMLS		  List all images found in NOR flash
1001		CONFIG_CMD_IMLS_NAND	* List all images found in NAND flash
1002		CONFIG_CMD_IMMAP	* IMMR dump support
1003		CONFIG_CMD_IOTRACE	* I/O tracing for debugging
1004		CONFIG_CMD_IMPORTENV	* import an environment
1005		CONFIG_CMD_INI		* import data from an ini file into the env
1006		CONFIG_CMD_IRQ		* irqinfo
1007		CONFIG_CMD_ITEST	  Integer/string test of 2 values
1008		CONFIG_CMD_JFFS2	* JFFS2 Support
1009		CONFIG_CMD_KGDB		* kgdb
1010		CONFIG_CMD_LDRINFO	* ldrinfo (display Blackfin loader)
1011		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
1012					  (169.254.*.*)
1013		CONFIG_CMD_LOADB	  loadb
1014		CONFIG_CMD_LOADS	  loads
1015		CONFIG_CMD_MD5SUM	* print md5 message digest
1016					  (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1017		CONFIG_CMD_MEMINFO	* Display detailed memory information
1018		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
1019					  loop, loopw
1020		CONFIG_CMD_MEMTEST	* mtest
1021		CONFIG_CMD_MISC		  Misc functions like sleep etc
1022		CONFIG_CMD_MMC		* MMC memory mapped support
1023		CONFIG_CMD_MII		* MII utility commands
1024		CONFIG_CMD_MTDPARTS	* MTD partition support
1025		CONFIG_CMD_NAND		* NAND support
1026		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
1027		CONFIG_CMD_NFS		  NFS support
1028		CONFIG_CMD_PCA953X	* PCA953x I2C gpio commands
1029		CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1030		CONFIG_CMD_PCI		* pciinfo
1031		CONFIG_CMD_PCMCIA		* PCMCIA support
1032		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
1033					  host
1034		CONFIG_CMD_PORTIO	* Port I/O
1035		CONFIG_CMD_READ		* Read raw data from partition
1036		CONFIG_CMD_REGINFO	* Register dump
1037		CONFIG_CMD_RUN		  run command in env variable
1038		CONFIG_CMD_SANDBOX	* sb command to access sandbox features
1039		CONFIG_CMD_SAVES	* save S record dump
1040		CONFIG_CMD_SCSI		* SCSI Support
1041		CONFIG_CMD_SDRAM	* print SDRAM configuration information
1042					  (requires CONFIG_CMD_I2C)
1043		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
1044					  (4xx only)
1045		CONFIG_CMD_SF		* Read/write/erase SPI NOR flash
1046		CONFIG_CMD_SHA1SUM	* print sha1 memory digest
1047					  (requires CONFIG_CMD_MEMORY)
1048		CONFIG_CMD_SOFTSWITCH	* Soft switch setting command for BF60x
1049		CONFIG_CMD_SOURCE	  "source" command Support
1050		CONFIG_CMD_SPI		* SPI serial bus support
1051		CONFIG_CMD_TFTPSRV	* TFTP transfer in server mode
1052		CONFIG_CMD_TFTPPUT	* TFTP put command (upload)
1053		CONFIG_CMD_TIME		* run command and report execution time (ARM specific)
1054		CONFIG_CMD_TIMER	* access to the system tick timer
1055		CONFIG_CMD_USB		* USB support
1056		CONFIG_CMD_CDP		* Cisco Discover Protocol support
1057		CONFIG_CMD_MFSL		* Microblaze FSL support
1058		CONFIG_CMD_XIMG		  Load part of Multi Image
1059		CONFIG_CMD_UUID		* Generate random UUID or GUID string
1060
1061		EXAMPLE: If you want all functions except of network
1062		support you can write:
1063
1064		#include "config_cmd_all.h"
1065		#undef CONFIG_CMD_NET
1066
1067	Other Commands:
1068		fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1069
1070	Note:	Don't enable the "icache" and "dcache" commands
1071		(configuration option CONFIG_CMD_CACHE) unless you know
1072		what you (and your U-Boot users) are doing. Data
1073		cache cannot be enabled on systems like the 8xx or
1074		8260 (where accesses to the IMMR region must be
1075		uncached), and it cannot be disabled on all other
1076		systems where we (mis-) use the data cache to hold an
1077		initial stack and some data.
1078
1079
1080		XXX - this list needs to get updated!
1081
1082- Regular expression support:
1083		CONFIG_REGEX
1084		If this variable is defined, U-Boot is linked against
1085		the SLRE (Super Light Regular Expression) library,
1086		which adds regex support to some commands, as for
1087		example "env grep" and "setexpr".
1088
1089- Device tree:
1090		CONFIG_OF_CONTROL
1091		If this variable is defined, U-Boot will use a device tree
1092		to configure its devices, instead of relying on statically
1093		compiled #defines in the board file. This option is
1094		experimental and only available on a few boards. The device
1095		tree is available in the global data as gd->fdt_blob.
1096
1097		U-Boot needs to get its device tree from somewhere. This can
1098		be done using one of the two options below:
1099
1100		CONFIG_OF_EMBED
1101		If this variable is defined, U-Boot will embed a device tree
1102		binary in its image. This device tree file should be in the
1103		board directory and called <soc>-<board>.dts. The binary file
1104		is then picked up in board_init_f() and made available through
1105		the global data structure as gd->blob.
1106
1107		CONFIG_OF_SEPARATE
1108		If this variable is defined, U-Boot will build a device tree
1109		binary. It will be called u-boot.dtb. Architecture-specific
1110		code will locate it at run-time. Generally this works by:
1111
1112			cat u-boot.bin u-boot.dtb >image.bin
1113
1114		and in fact, U-Boot does this for you, creating a file called
1115		u-boot-dtb.bin which is useful in the common case. You can
1116		still use the individual files if you need something more
1117		exotic.
1118
1119- Watchdog:
1120		CONFIG_WATCHDOG
1121		If this variable is defined, it enables watchdog
1122		support for the SoC. There must be support in the SoC
1123		specific code for a watchdog. For the 8xx and 8260
1124		CPUs, the SIU Watchdog feature is enabled in the SYPCR
1125		register.  When supported for a specific SoC is
1126		available, then no further board specific code should
1127		be needed to use it.
1128
1129		CONFIG_HW_WATCHDOG
1130		When using a watchdog circuitry external to the used
1131		SoC, then define this variable and provide board
1132		specific code for the "hw_watchdog_reset" function.
1133
1134- U-Boot Version:
1135		CONFIG_VERSION_VARIABLE
1136		If this variable is defined, an environment variable
1137		named "ver" is created by U-Boot showing the U-Boot
1138		version as printed by the "version" command.
1139		Any change to this variable will be reverted at the
1140		next reset.
1141
1142- Real-Time Clock:
1143
1144		When CONFIG_CMD_DATE is selected, the type of the RTC
1145		has to be selected, too. Define exactly one of the
1146		following options:
1147
1148		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
1149		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
1150		CONFIG_RTC_MC13XXX	- use MC13783 or MC13892 RTC
1151		CONFIG_RTC_MC146818	- use MC146818 RTC
1152		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
1153		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
1154		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
1155		CONFIG_RTC_DS1339	- use Maxim, Inc. DS1339 RTC
1156		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
1157		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
1158		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
1159		CONFIG_SYS_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
1160		CONFIG_SYS_RV3029_TCR	- enable trickle charger on
1161					  RV3029 RTC.
1162
1163		Note that if the RTC uses I2C, then the I2C interface
1164		must also be configured. See I2C Support, below.
1165
1166- GPIO Support:
1167		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
1168
1169		The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1170		chip-ngpio pairs that tell the PCA953X driver the number of
1171		pins supported by a particular chip.
1172
1173		Note that if the GPIO device uses I2C, then the I2C interface
1174		must also be configured. See I2C Support, below.
1175
1176- I/O tracing:
1177		When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1178		accesses and can checksum them or write a list of them out
1179		to memory. See the 'iotrace' command for details. This is
1180		useful for testing device drivers since it can confirm that
1181		the driver behaves the same way before and after a code
1182		change. Currently this is supported on sandbox and arm. To
1183		add support for your architecture, add '#include <iotrace.h>'
1184		to the bottom of arch/<arch>/include/asm/io.h and test.
1185
1186		Example output from the 'iotrace stats' command is below.
1187		Note that if the trace buffer is exhausted, the checksum will
1188		still continue to operate.
1189
1190			iotrace is enabled
1191			Start:  10000000	(buffer start address)
1192			Size:   00010000	(buffer size)
1193			Offset: 00000120	(current buffer offset)
1194			Output: 10000120	(start + offset)
1195			Count:  00000018	(number of trace records)
1196			CRC32:  9526fb66	(CRC32 of all trace records)
1197
1198- Timestamp Support:
1199
1200		When CONFIG_TIMESTAMP is selected, the timestamp
1201		(date and time) of an image is printed by image
1202		commands like bootm or iminfo. This option is
1203		automatically enabled when you select CONFIG_CMD_DATE .
1204
1205- Partition Labels (disklabels) Supported:
1206		Zero or more of the following:
1207		CONFIG_MAC_PARTITION   Apple's MacOS partition table.
1208		CONFIG_DOS_PARTITION   MS Dos partition table, traditional on the
1209				       Intel architecture, USB sticks, etc.
1210		CONFIG_ISO_PARTITION   ISO partition table, used on CDROM etc.
1211		CONFIG_EFI_PARTITION   GPT partition table, common when EFI is the
1212				       bootloader.  Note 2TB partition limit; see
1213				       disk/part_efi.c
1214		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.
1215
1216		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1217		CONFIG_CMD_SCSI) you must configure support for at
1218		least one non-MTD partition type as well.
1219
1220- IDE Reset method:
1221		CONFIG_IDE_RESET_ROUTINE - this is defined in several
1222		board configurations files but used nowhere!
1223
1224		CONFIG_IDE_RESET - is this is defined, IDE Reset will
1225		be performed by calling the function
1226			ide_set_reset(int reset)
1227		which has to be defined in a board specific file
1228
1229- ATAPI Support:
1230		CONFIG_ATAPI
1231
1232		Set this to enable ATAPI support.
1233
1234- LBA48 Support
1235		CONFIG_LBA48
1236
1237		Set this to enable support for disks larger than 137GB
1238		Also look at CONFIG_SYS_64BIT_LBA.
1239		Whithout these , LBA48 support uses 32bit variables and will 'only'
1240		support disks up to 2.1TB.
1241
1242		CONFIG_SYS_64BIT_LBA:
1243			When enabled, makes the IDE subsystem use 64bit sector addresses.
1244			Default is 32bit.
1245
1246- SCSI Support:
1247		At the moment only there is only support for the
1248		SYM53C8XX SCSI controller; define
1249		CONFIG_SCSI_SYM53C8XX to enable it.
1250
1251		CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1252		CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1253		CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1254		maximum numbers of LUNs, SCSI ID's and target
1255		devices.
1256		CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1257
1258		The environment variable 'scsidevs' is set to the number of
1259		SCSI devices found during the last scan.
1260
1261- NETWORK Support (PCI):
1262		CONFIG_E1000
1263		Support for Intel 8254x/8257x gigabit chips.
1264
1265		CONFIG_E1000_SPI
1266		Utility code for direct access to the SPI bus on Intel 8257x.
1267		This does not do anything useful unless you set at least one
1268		of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1269
1270		CONFIG_E1000_SPI_GENERIC
1271		Allow generic access to the SPI bus on the Intel 8257x, for
1272		example with the "sspi" command.
1273
1274		CONFIG_CMD_E1000
1275		Management command for E1000 devices.  When used on devices
1276		with SPI support you can reprogram the EEPROM from U-Boot.
1277
1278		CONFIG_E1000_FALLBACK_MAC
1279		default MAC for empty EEPROM after production.
1280
1281		CONFIG_EEPRO100
1282		Support for Intel 82557/82559/82559ER chips.
1283		Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1284		write routine for first time initialisation.
1285
1286		CONFIG_TULIP
1287		Support for Digital 2114x chips.
1288		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1289		modem chip initialisation (KS8761/QS6611).
1290
1291		CONFIG_NATSEMI
1292		Support for National dp83815 chips.
1293
1294		CONFIG_NS8382X
1295		Support for National dp8382[01] gigabit chips.
1296
1297- NETWORK Support (other):
1298
1299		CONFIG_DRIVER_AT91EMAC
1300		Support for AT91RM9200 EMAC.
1301
1302			CONFIG_RMII
1303			Define this to use reduced MII inteface
1304
1305			CONFIG_DRIVER_AT91EMAC_QUIET
1306			If this defined, the driver is quiet.
1307			The driver doen't show link status messages.
1308
1309		CONFIG_CALXEDA_XGMAC
1310		Support for the Calxeda XGMAC device
1311
1312		CONFIG_LAN91C96
1313		Support for SMSC's LAN91C96 chips.
1314
1315			CONFIG_LAN91C96_BASE
1316			Define this to hold the physical address
1317			of the LAN91C96's I/O space
1318
1319			CONFIG_LAN91C96_USE_32_BIT
1320			Define this to enable 32 bit addressing
1321
1322		CONFIG_SMC91111
1323		Support for SMSC's LAN91C111 chip
1324
1325			CONFIG_SMC91111_BASE
1326			Define this to hold the physical address
1327			of the device (I/O space)
1328
1329			CONFIG_SMC_USE_32_BIT
1330			Define this if data bus is 32 bits
1331
1332			CONFIG_SMC_USE_IOFUNCS
1333			Define this to use i/o functions instead of macros
1334			(some hardware wont work with macros)
1335
1336		CONFIG_DRIVER_TI_EMAC
1337		Support for davinci emac
1338
1339			CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1340			Define this if you have more then 3 PHYs.
1341
1342		CONFIG_FTGMAC100
1343		Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1344
1345			CONFIG_FTGMAC100_EGIGA
1346			Define this to use GE link update with gigabit PHY.
1347			Define this if FTGMAC100 is connected to gigabit PHY.
1348			If your system has 10/100 PHY only, it might not occur
1349			wrong behavior. Because PHY usually return timeout or
1350			useless data when polling gigabit status and gigabit
1351			control registers. This behavior won't affect the
1352			correctnessof 10/100 link speed update.
1353
1354		CONFIG_SMC911X
1355		Support for SMSC's LAN911x and LAN921x chips
1356
1357			CONFIG_SMC911X_BASE
1358			Define this to hold the physical address
1359			of the device (I/O space)
1360
1361			CONFIG_SMC911X_32_BIT
1362			Define this if data bus is 32 bits
1363
1364			CONFIG_SMC911X_16_BIT
1365			Define this if data bus is 16 bits. If your processor
1366			automatically converts one 32 bit word to two 16 bit
1367			words you may also try CONFIG_SMC911X_32_BIT.
1368
1369		CONFIG_SH_ETHER
1370		Support for Renesas on-chip Ethernet controller
1371
1372			CONFIG_SH_ETHER_USE_PORT
1373			Define the number of ports to be used
1374
1375			CONFIG_SH_ETHER_PHY_ADDR
1376			Define the ETH PHY's address
1377
1378			CONFIG_SH_ETHER_CACHE_WRITEBACK
1379			If this option is set, the driver enables cache flush.
1380
1381- TPM Support:
1382		CONFIG_TPM
1383		Support TPM devices.
1384
1385		CONFIG_TPM_TIS_I2C
1386		Support for i2c bus TPM devices. Only one device
1387		per system is supported at this time.
1388
1389			CONFIG_TPM_TIS_I2C_BUS_NUMBER
1390			Define the the i2c bus number for the TPM device
1391
1392			CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1393			Define the TPM's address on the i2c bus
1394
1395			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1396			Define the burst count bytes upper limit
1397
1398		CONFIG_TPM_ATMEL_TWI
1399		Support for Atmel TWI TPM device. Requires I2C support.
1400
1401		CONFIG_TPM_TIS_LPC
1402		Support for generic parallel port TPM devices. Only one device
1403		per system is supported at this time.
1404
1405			CONFIG_TPM_TIS_BASE_ADDRESS
1406			Base address where the generic TPM device is mapped
1407			to. Contemporary x86 systems usually map it at
1408			0xfed40000.
1409
1410		CONFIG_CMD_TPM
1411		Add tpm monitor functions.
1412		Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1413		provides monitor access to authorized functions.
1414
1415		CONFIG_TPM
1416		Define this to enable the TPM support library which provides
1417		functional interfaces to some TPM commands.
1418		Requires support for a TPM device.
1419
1420		CONFIG_TPM_AUTH_SESSIONS
1421		Define this to enable authorized functions in the TPM library.
1422		Requires CONFIG_TPM and CONFIG_SHA1.
1423
1424- USB Support:
1425		At the moment only the UHCI host controller is
1426		supported (PIP405, MIP405, MPC5200); define
1427		CONFIG_USB_UHCI to enable it.
1428		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1429		and define CONFIG_USB_STORAGE to enable the USB
1430		storage devices.
1431		Note:
1432		Supported are USB Keyboards and USB Floppy drives
1433		(TEAC FD-05PUB).
1434		MPC5200 USB requires additional defines:
1435			CONFIG_USB_CLOCK
1436				for 528 MHz Clock: 0x0001bbbb
1437			CONFIG_PSC3_USB
1438				for USB on PSC3
1439			CONFIG_USB_CONFIG
1440				for differential drivers: 0x00001000
1441				for single ended drivers: 0x00005000
1442				for differential drivers on PSC3: 0x00000100
1443				for single ended drivers on PSC3: 0x00004100
1444			CONFIG_SYS_USB_EVENT_POLL
1445				May be defined to allow interrupt polling
1446				instead of using asynchronous interrupts
1447
1448		CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1449		txfilltuning field in the EHCI controller on reset.
1450
1451- USB Device:
1452		Define the below if you wish to use the USB console.
1453		Once firmware is rebuilt from a serial console issue the
1454		command "setenv stdin usbtty; setenv stdout usbtty" and
1455		attach your USB cable. The Unix command "dmesg" should print
1456		it has found a new device. The environment variable usbtty
1457		can be set to gserial or cdc_acm to enable your device to
1458		appear to a USB host as a Linux gserial device or a
1459		Common Device Class Abstract Control Model serial device.
1460		If you select usbtty = gserial you should be able to enumerate
1461		a Linux host by
1462		# modprobe usbserial vendor=0xVendorID product=0xProductID
1463		else if using cdc_acm, simply setting the environment
1464		variable usbtty to be cdc_acm should suffice. The following
1465		might be defined in YourBoardName.h
1466
1467			CONFIG_USB_DEVICE
1468			Define this to build a UDC device
1469
1470			CONFIG_USB_TTY
1471			Define this to have a tty type of device available to
1472			talk to the UDC device
1473
1474			CONFIG_USBD_HS
1475			Define this to enable the high speed support for usb
1476			device and usbtty. If this feature is enabled, a routine
1477			int is_usbd_high_speed(void)
1478			also needs to be defined by the driver to dynamically poll
1479			whether the enumeration has succeded at high speed or full
1480			speed.
1481
1482			CONFIG_SYS_CONSOLE_IS_IN_ENV
1483			Define this if you want stdin, stdout &/or stderr to
1484			be set to usbtty.
1485
1486			mpc8xx:
1487				CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1488				Derive USB clock from external clock "blah"
1489				- CONFIG_SYS_USB_EXTC_CLK 0x02
1490
1491				CONFIG_SYS_USB_BRG_CLK 0xBLAH
1492				Derive USB clock from brgclk
1493				- CONFIG_SYS_USB_BRG_CLK 0x04
1494
1495		If you have a USB-IF assigned VendorID then you may wish to
1496		define your own vendor specific values either in BoardName.h
1497		or directly in usbd_vendor_info.h. If you don't define
1498		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1499		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1500		should pretend to be a Linux device to it's target host.
1501
1502			CONFIG_USBD_MANUFACTURER
1503			Define this string as the name of your company for
1504			- CONFIG_USBD_MANUFACTURER "my company"
1505
1506			CONFIG_USBD_PRODUCT_NAME
1507			Define this string as the name of your product
1508			- CONFIG_USBD_PRODUCT_NAME "acme usb device"
1509
1510			CONFIG_USBD_VENDORID
1511			Define this as your assigned Vendor ID from the USB
1512			Implementors Forum. This *must* be a genuine Vendor ID
1513			to avoid polluting the USB namespace.
1514			- CONFIG_USBD_VENDORID 0xFFFF
1515
1516			CONFIG_USBD_PRODUCTID
1517			Define this as the unique Product ID
1518			for your device
1519			- CONFIG_USBD_PRODUCTID 0xFFFF
1520
1521- ULPI Layer Support:
1522		The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1523		the generic ULPI layer. The generic layer accesses the ULPI PHY
1524		via the platform viewport, so you need both the genric layer and
1525		the viewport enabled. Currently only Chipidea/ARC based
1526		viewport is supported.
1527		To enable the ULPI layer support, define CONFIG_USB_ULPI and
1528		CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1529		If your ULPI phy needs a different reference clock than the
1530		standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1531		the appropriate value in Hz.
1532
1533- MMC Support:
1534		The MMC controller on the Intel PXA is supported. To
1535		enable this define CONFIG_MMC. The MMC can be
1536		accessed from the boot prompt by mapping the device
1537		to physical memory similar to flash. Command line is
1538		enabled with CONFIG_CMD_MMC. The MMC driver also works with
1539		the FAT fs. This is enabled with CONFIG_CMD_FAT.
1540
1541		CONFIG_SH_MMCIF
1542		Support for Renesas on-chip MMCIF controller
1543
1544			CONFIG_SH_MMCIF_ADDR
1545			Define the base address of MMCIF registers
1546
1547			CONFIG_SH_MMCIF_CLK
1548			Define the clock frequency for MMCIF
1549
1550		CONFIG_GENERIC_MMC
1551		Enable the generic MMC driver
1552
1553		CONFIG_SUPPORT_EMMC_BOOT
1554		Enable some additional features of the eMMC boot partitions.
1555
1556		CONFIG_SUPPORT_EMMC_RPMB
1557		Enable the commands for reading, writing and programming the
1558		key for the Replay Protection Memory Block partition in eMMC.
1559
1560- USB Device Firmware Update (DFU) class support:
1561		CONFIG_DFU_FUNCTION
1562		This enables the USB portion of the DFU USB class
1563
1564		CONFIG_CMD_DFU
1565		This enables the command "dfu" which is used to have
1566		U-Boot create a DFU class device via USB.  This command
1567		requires that the "dfu_alt_info" environment variable be
1568		set and define the alt settings to expose to the host.
1569
1570		CONFIG_DFU_MMC
1571		This enables support for exposing (e)MMC devices via DFU.
1572
1573		CONFIG_DFU_NAND
1574		This enables support for exposing NAND devices via DFU.
1575
1576		CONFIG_DFU_RAM
1577		This enables support for exposing RAM via DFU.
1578		Note: DFU spec refer to non-volatile memory usage, but
1579		allow usages beyond the scope of spec - here RAM usage,
1580		one that would help mostly the developer.
1581
1582		CONFIG_SYS_DFU_DATA_BUF_SIZE
1583		Dfu transfer uses a buffer before writing data to the
1584		raw storage device. Make the size (in bytes) of this buffer
1585		configurable. The size of this buffer is also configurable
1586		through the "dfu_bufsiz" environment variable.
1587
1588		CONFIG_SYS_DFU_MAX_FILE_SIZE
1589		When updating files rather than the raw storage device,
1590		we use a static buffer to copy the file into and then write
1591		the buffer once we've been given the whole file.  Define
1592		this to the maximum filesize (in bytes) for the buffer.
1593		Default is 4 MiB if undefined.
1594
1595		DFU_DEFAULT_POLL_TIMEOUT
1596		Poll timeout [ms], is the timeout a device can send to the
1597		host. The host must wait for this timeout before sending
1598		a subsequent DFU_GET_STATUS request to the device.
1599
1600		DFU_MANIFEST_POLL_TIMEOUT
1601		Poll timeout [ms], which the device sends to the host when
1602		entering dfuMANIFEST state. Host waits this timeout, before
1603		sending again an USB request to the device.
1604
1605- USB Device Android Fastboot support:
1606		CONFIG_CMD_FASTBOOT
1607		This enables the command "fastboot" which enables the Android
1608		fastboot mode for the platform's USB device. Fastboot is a USB
1609		protocol for downloading images, flashing and device control
1610		used on Android devices.
1611		See doc/README.android-fastboot for more information.
1612
1613		CONFIG_ANDROID_BOOT_IMAGE
1614		This enables support for booting images which use the Android
1615		image format header.
1616
1617		CONFIG_USB_FASTBOOT_BUF_ADDR
1618		The fastboot protocol requires a large memory buffer for
1619		downloads. Define this to the starting RAM address to use for
1620		downloaded images.
1621
1622		CONFIG_USB_FASTBOOT_BUF_SIZE
1623		The fastboot protocol requires a large memory buffer for
1624		downloads. This buffer should be as large as possible for a
1625		platform. Define this to the size available RAM for fastboot.
1626
1627- Journaling Flash filesystem support:
1628		CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1629		CONFIG_JFFS2_NAND_DEV
1630		Define these for a default partition on a NAND device
1631
1632		CONFIG_SYS_JFFS2_FIRST_SECTOR,
1633		CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1634		Define these for a default partition on a NOR device
1635
1636		CONFIG_SYS_JFFS_CUSTOM_PART
1637		Define this to create an own partition. You have to provide a
1638		function struct part_info* jffs2_part_info(int part_num)
1639
1640		If you define only one JFFS2 partition you may also want to
1641		#define CONFIG_SYS_JFFS_SINGLE_PART	1
1642		to disable the command chpart. This is the default when you
1643		have not defined a custom partition
1644
1645- FAT(File Allocation Table) filesystem write function support:
1646		CONFIG_FAT_WRITE
1647
1648		Define this to enable support for saving memory data as a
1649		file in FAT formatted partition.
1650
1651		This will also enable the command "fatwrite" enabling the
1652		user to write files to FAT.
1653
1654CBFS (Coreboot Filesystem) support
1655		CONFIG_CMD_CBFS
1656
1657		Define this to enable support for reading from a Coreboot
1658		filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1659		and cbfsload.
1660
1661- FAT(File Allocation Table) filesystem cluster size:
1662		CONFIG_FS_FAT_MAX_CLUSTSIZE
1663
1664		Define the max cluster size for fat operations else
1665		a default value of 65536 will be defined.
1666
1667- Keyboard Support:
1668		CONFIG_ISA_KEYBOARD
1669
1670		Define this to enable standard (PC-Style) keyboard
1671		support
1672
1673		CONFIG_I8042_KBD
1674		Standard PC keyboard driver with US (is default) and
1675		GERMAN key layout (switch via environment 'keymap=de') support.
1676		Export function i8042_kbd_init, i8042_tstc and i8042_getc
1677		for cfb_console. Supports cursor blinking.
1678
1679		CONFIG_CROS_EC_KEYB
1680		Enables a Chrome OS keyboard using the CROS_EC interface.
1681		This uses CROS_EC to communicate with a second microcontroller
1682		which provides key scans on request.
1683
1684- Video support:
1685		CONFIG_VIDEO
1686
1687		Define this to enable video support (for output to
1688		video).
1689
1690		CONFIG_VIDEO_CT69000
1691
1692		Enable Chips & Technologies 69000 Video chip
1693
1694		CONFIG_VIDEO_SMI_LYNXEM
1695		Enable Silicon Motion SMI 712/710/810 Video chip. The
1696		video output is selected via environment 'videoout'
1697		(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1698		assumed.
1699
1700		For the CT69000 and SMI_LYNXEM drivers, videomode is
1701		selected via environment 'videomode'. Two different ways
1702		are possible:
1703		- "videomode=num"   'num' is a standard LiLo mode numbers.
1704		Following standard modes are supported	(* is default):
1705
1706		      Colors	640x480 800x600 1024x768 1152x864 1280x1024
1707		-------------+---------------------------------------------
1708		      8 bits |	0x301*	0x303	 0x305	  0x161	    0x307
1709		     15 bits |	0x310	0x313	 0x316	  0x162	    0x319
1710		     16 bits |	0x311	0x314	 0x317	  0x163	    0x31A
1711		     24 bits |	0x312	0x315	 0x318	    ?	    0x31B
1712		-------------+---------------------------------------------
1713		(i.e. setenv videomode 317; saveenv; reset;)
1714
1715		- "videomode=bootargs" all the video parameters are parsed
1716		from the bootargs. (See drivers/video/videomodes.c)
1717
1718
1719		CONFIG_VIDEO_SED13806
1720		Enable Epson SED13806 driver. This driver supports 8bpp
1721		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1722		or CONFIG_VIDEO_SED13806_16BPP
1723
1724		CONFIG_FSL_DIU_FB
1725		Enable the Freescale DIU video driver.	Reference boards for
1726		SOCs that have a DIU should define this macro to enable DIU
1727		support, and should also define these other macros:
1728
1729			CONFIG_SYS_DIU_ADDR
1730			CONFIG_VIDEO
1731			CONFIG_CMD_BMP
1732			CONFIG_CFB_CONSOLE
1733			CONFIG_VIDEO_SW_CURSOR
1734			CONFIG_VGA_AS_SINGLE_DEVICE
1735			CONFIG_VIDEO_LOGO
1736			CONFIG_VIDEO_BMP_LOGO
1737
1738		The DIU driver will look for the 'video-mode' environment
1739		variable, and if defined, enable the DIU as a console during
1740		boot.  See the documentation file README.video for a
1741		description of this variable.
1742
1743		CONFIG_VIDEO_VGA
1744
1745		Enable the VGA video / BIOS for x86. The alternative if you
1746		are using coreboot is to use the coreboot frame buffer
1747		driver.
1748
1749
1750- Keyboard Support:
1751		CONFIG_KEYBOARD
1752
1753		Define this to enable a custom keyboard support.
1754		This simply calls drv_keyboard_init() which must be
1755		defined in your board-specific files.
1756		The only board using this so far is RBC823.
1757
1758- LCD Support:	CONFIG_LCD
1759
1760		Define this to enable LCD support (for output to LCD
1761		display); also select one of the supported displays
1762		by defining one of these:
1763
1764		CONFIG_ATMEL_LCD:
1765
1766			HITACHI TX09D70VM1CCA, 3.5", 240x320.
1767
1768		CONFIG_NEC_NL6448AC33:
1769
1770			NEC NL6448AC33-18. Active, color, single scan.
1771
1772		CONFIG_NEC_NL6448BC20
1773
1774			NEC NL6448BC20-08. 6.5", 640x480.
1775			Active, color, single scan.
1776
1777		CONFIG_NEC_NL6448BC33_54
1778
1779			NEC NL6448BC33-54. 10.4", 640x480.
1780			Active, color, single scan.
1781
1782		CONFIG_SHARP_16x9
1783
1784			Sharp 320x240. Active, color, single scan.
1785			It isn't 16x9, and I am not sure what it is.
1786
1787		CONFIG_SHARP_LQ64D341
1788
1789			Sharp LQ64D341 display, 640x480.
1790			Active, color, single scan.
1791
1792		CONFIG_HLD1045
1793
1794			HLD1045 display, 640x480.
1795			Active, color, single scan.
1796
1797		CONFIG_OPTREX_BW
1798
1799			Optrex	 CBL50840-2 NF-FW 99 22 M5
1800			or
1801			Hitachi	 LMG6912RPFC-00T
1802			or
1803			Hitachi	 SP14Q002
1804
1805			320x240. Black & white.
1806
1807		Normally display is black on white background; define
1808		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1809
1810		CONFIG_LCD_ALIGNMENT
1811
1812		Normally the LCD is page-aligned (tyically 4KB). If this is
1813		defined then the LCD will be aligned to this value instead.
1814		For ARM it is sometimes useful to use MMU_SECTION_SIZE
1815		here, since it is cheaper to change data cache settings on
1816		a per-section basis.
1817
1818		CONFIG_CONSOLE_SCROLL_LINES
1819
1820		When the console need to be scrolled, this is the number of
1821		lines to scroll by. It defaults to 1. Increasing this makes
1822		the console jump but can help speed up operation when scrolling
1823		is slow.
1824
1825		CONFIG_LCD_BMP_RLE8
1826
1827		Support drawing of RLE8-compressed bitmaps on the LCD.
1828
1829		CONFIG_I2C_EDID
1830
1831		Enables an 'i2c edid' command which can read EDID
1832		information over I2C from an attached LCD display.
1833
1834- Splash Screen Support: CONFIG_SPLASH_SCREEN
1835
1836		If this option is set, the environment is checked for
1837		a variable "splashimage". If found, the usual display
1838		of logo, copyright and system information on the LCD
1839		is suppressed and the BMP image at the address
1840		specified in "splashimage" is loaded instead. The
1841		console is redirected to the "nulldev", too. This
1842		allows for a "silent" boot where a splash screen is
1843		loaded very quickly after power-on.
1844
1845		CONFIG_SPLASHIMAGE_GUARD
1846
1847		If this option is set, then U-Boot will prevent the environment
1848		variable "splashimage" from being set to a problematic address
1849		(see README.displaying-bmps).
1850		This option is useful for targets where, due to alignment
1851		restrictions, an improperly aligned BMP image will cause a data
1852		abort. If you think you will not have problems with unaligned
1853		accesses (for example because your toolchain prevents them)
1854		there is no need to set this option.
1855
1856		CONFIG_SPLASH_SCREEN_ALIGN
1857
1858		If this option is set the splash image can be freely positioned
1859		on the screen. Environment variable "splashpos" specifies the
1860		position as "x,y". If a positive number is given it is used as
1861		number of pixel from left/top. If a negative number is given it
1862		is used as number of pixel from right/bottom. You can also
1863		specify 'm' for centering the image.
1864
1865		Example:
1866		setenv splashpos m,m
1867			=> image at center of screen
1868
1869		setenv splashpos 30,20
1870			=> image at x = 30 and y = 20
1871
1872		setenv splashpos -10,m
1873			=> vertically centered image
1874			   at x = dspWidth - bmpWidth - 9
1875
1876- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1877
1878		If this option is set, additionally to standard BMP
1879		images, gzipped BMP images can be displayed via the
1880		splashscreen support or the bmp command.
1881
1882- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1883
1884		If this option is set, 8-bit RLE compressed BMP images
1885		can be displayed via the splashscreen support or the
1886		bmp command.
1887
1888- Do compresssing for memory range:
1889		CONFIG_CMD_ZIP
1890
1891		If this option is set, it would use zlib deflate method
1892		to compress the specified memory at its best effort.
1893
1894- Compression support:
1895		CONFIG_GZIP
1896
1897		Enabled by default to support gzip compressed images.
1898
1899		CONFIG_BZIP2
1900
1901		If this option is set, support for bzip2 compressed
1902		images is included. If not, only uncompressed and gzip
1903		compressed images are supported.
1904
1905		NOTE: the bzip2 algorithm requires a lot of RAM, so
1906		the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1907		be at least 4MB.
1908
1909		CONFIG_LZMA
1910
1911		If this option is set, support for lzma compressed
1912		images is included.
1913
1914		Note: The LZMA algorithm adds between 2 and 4KB of code and it
1915		requires an amount of dynamic memory that is given by the
1916		formula:
1917
1918			(1846 + 768 << (lc + lp)) * sizeof(uint16)
1919
1920		Where lc and lp stand for, respectively, Literal context bits
1921		and Literal pos bits.
1922
1923		This value is upper-bounded by 14MB in the worst case. Anyway,
1924		for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1925		total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1926		a very small buffer.
1927
1928		Use the lzmainfo tool to determinate the lc and lp values and
1929		then calculate the amount of needed dynamic memory (ensuring
1930		the appropriate CONFIG_SYS_MALLOC_LEN value).
1931
1932		CONFIG_LZO
1933
1934		If this option is set, support for LZO compressed images
1935		is included.
1936
1937- MII/PHY support:
1938		CONFIG_PHY_ADDR
1939
1940		The address of PHY on MII bus.
1941
1942		CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1943
1944		The clock frequency of the MII bus
1945
1946		CONFIG_PHY_GIGE
1947
1948		If this option is set, support for speed/duplex
1949		detection of gigabit PHY is included.
1950
1951		CONFIG_PHY_RESET_DELAY
1952
1953		Some PHY like Intel LXT971A need extra delay after
1954		reset before any MII register access is possible.
1955		For such PHY, set this option to the usec delay
1956		required. (minimum 300usec for LXT971A)
1957
1958		CONFIG_PHY_CMD_DELAY (ppc4xx)
1959
1960		Some PHY like Intel LXT971A need extra delay after
1961		command issued before MII status register can be read
1962
1963- Ethernet address:
1964		CONFIG_ETHADDR
1965		CONFIG_ETH1ADDR
1966		CONFIG_ETH2ADDR
1967		CONFIG_ETH3ADDR
1968		CONFIG_ETH4ADDR
1969		CONFIG_ETH5ADDR
1970
1971		Define a default value for Ethernet address to use
1972		for the respective Ethernet interface, in case this
1973		is not determined automatically.
1974
1975- IP address:
1976		CONFIG_IPADDR
1977
1978		Define a default value for the IP address to use for
1979		the default Ethernet interface, in case this is not
1980		determined through e.g. bootp.
1981		(Environment variable "ipaddr")
1982
1983- Server IP address:
1984		CONFIG_SERVERIP
1985
1986		Defines a default value for the IP address of a TFTP
1987		server to contact when using the "tftboot" command.
1988		(Environment variable "serverip")
1989
1990		CONFIG_KEEP_SERVERADDR
1991
1992		Keeps the server's MAC address, in the env 'serveraddr'
1993		for passing to bootargs (like Linux's netconsole option)
1994
1995- Gateway IP address:
1996		CONFIG_GATEWAYIP
1997
1998		Defines a default value for the IP address of the
1999		default router where packets to other networks are
2000		sent to.
2001		(Environment variable "gatewayip")
2002
2003- Subnet mask:
2004		CONFIG_NETMASK
2005
2006		Defines a default value for the subnet mask (or
2007		routing prefix) which is used to determine if an IP
2008		address belongs to the local subnet or needs to be
2009		forwarded through a router.
2010		(Environment variable "netmask")
2011
2012- Multicast TFTP Mode:
2013		CONFIG_MCAST_TFTP
2014
2015		Defines whether you want to support multicast TFTP as per
2016		rfc-2090; for example to work with atftp.  Lets lots of targets
2017		tftp down the same boot image concurrently.  Note: the Ethernet
2018		driver in use must provide a function: mcast() to join/leave a
2019		multicast group.
2020
2021- BOOTP Recovery Mode:
2022		CONFIG_BOOTP_RANDOM_DELAY
2023
2024		If you have many targets in a network that try to
2025		boot using BOOTP, you may want to avoid that all
2026		systems send out BOOTP requests at precisely the same
2027		moment (which would happen for instance at recovery
2028		from a power failure, when all systems will try to
2029		boot, thus flooding the BOOTP server. Defining
2030		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2031		inserted before sending out BOOTP requests. The
2032		following delays are inserted then:
2033
2034		1st BOOTP request:	delay 0 ... 1 sec
2035		2nd BOOTP request:	delay 0 ... 2 sec
2036		3rd BOOTP request:	delay 0 ... 4 sec
2037		4th and following
2038		BOOTP requests:		delay 0 ... 8 sec
2039
2040- DHCP Advanced Options:
2041		You can fine tune the DHCP functionality by defining
2042		CONFIG_BOOTP_* symbols:
2043
2044		CONFIG_BOOTP_SUBNETMASK
2045		CONFIG_BOOTP_GATEWAY
2046		CONFIG_BOOTP_HOSTNAME
2047		CONFIG_BOOTP_NISDOMAIN
2048		CONFIG_BOOTP_BOOTPATH
2049		CONFIG_BOOTP_BOOTFILESIZE
2050		CONFIG_BOOTP_DNS
2051		CONFIG_BOOTP_DNS2
2052		CONFIG_BOOTP_SEND_HOSTNAME
2053		CONFIG_BOOTP_NTPSERVER
2054		CONFIG_BOOTP_TIMEOFFSET
2055		CONFIG_BOOTP_VENDOREX
2056		CONFIG_BOOTP_MAY_FAIL
2057
2058		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2059		environment variable, not the BOOTP server.
2060
2061		CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2062		after the configured retry count, the call will fail
2063		instead of starting over.  This can be used to fail over
2064		to Link-local IP address configuration if the DHCP server
2065		is not available.
2066
2067		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2068		serverip from a DHCP server, it is possible that more
2069		than one DNS serverip is offered to the client.
2070		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2071		serverip will be stored in the additional environment
2072		variable "dnsip2". The first DNS serverip is always
2073		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2074		is defined.
2075
2076		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2077		to do a dynamic update of a DNS server. To do this, they
2078		need the hostname of the DHCP requester.
2079		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2080		of the "hostname" environment variable is passed as
2081		option 12 to the DHCP server.
2082
2083		CONFIG_BOOTP_DHCP_REQUEST_DELAY
2084
2085		A 32bit value in microseconds for a delay between
2086		receiving a "DHCP Offer" and sending the "DHCP Request".
2087		This fixes a problem with certain DHCP servers that don't
2088		respond 100% of the time to a "DHCP request". E.g. On an
2089		AT91RM9200 processor running at 180MHz, this delay needed
2090		to be *at least* 15,000 usec before a Windows Server 2003
2091		DHCP server would reply 100% of the time. I recommend at
2092		least 50,000 usec to be safe. The alternative is to hope
2093		that one of the retries will be successful but note that
2094		the DHCP timeout and retry process takes a longer than
2095		this delay.
2096
2097 - Link-local IP address negotiation:
2098		Negotiate with other link-local clients on the local network
2099		for an address that doesn't require explicit configuration.
2100		This is especially useful if a DHCP server cannot be guaranteed
2101		to exist in all environments that the device must operate.
2102
2103		See doc/README.link-local for more information.
2104
2105 - CDP Options:
2106		CONFIG_CDP_DEVICE_ID
2107
2108		The device id used in CDP trigger frames.
2109
2110		CONFIG_CDP_DEVICE_ID_PREFIX
2111
2112		A two character string which is prefixed to the MAC address
2113		of the device.
2114
2115		CONFIG_CDP_PORT_ID
2116
2117		A printf format string which contains the ascii name of
2118		the port. Normally is set to "eth%d" which sets
2119		eth0 for the first Ethernet, eth1 for the second etc.
2120
2121		CONFIG_CDP_CAPABILITIES
2122
2123		A 32bit integer which indicates the device capabilities;
2124		0x00000010 for a normal host which does not forwards.
2125
2126		CONFIG_CDP_VERSION
2127
2128		An ascii string containing the version of the software.
2129
2130		CONFIG_CDP_PLATFORM
2131
2132		An ascii string containing the name of the platform.
2133
2134		CONFIG_CDP_TRIGGER
2135
2136		A 32bit integer sent on the trigger.
2137
2138		CONFIG_CDP_POWER_CONSUMPTION
2139
2140		A 16bit integer containing the power consumption of the
2141		device in .1 of milliwatts.
2142
2143		CONFIG_CDP_APPLIANCE_VLAN_TYPE
2144
2145		A byte containing the id of the VLAN.
2146
2147- Status LED:	CONFIG_STATUS_LED
2148
2149		Several configurations allow to display the current
2150		status using a LED. For instance, the LED will blink
2151		fast while running U-Boot code, stop blinking as
2152		soon as a reply to a BOOTP request was received, and
2153		start blinking slow once the Linux kernel is running
2154		(supported by a status LED driver in the Linux
2155		kernel). Defining CONFIG_STATUS_LED enables this
2156		feature in U-Boot.
2157
2158		Additional options:
2159
2160		CONFIG_GPIO_LED
2161		The status LED can be connected to a GPIO pin.
2162		In such cases, the gpio_led driver can be used as a
2163		status LED backend implementation. Define CONFIG_GPIO_LED
2164		to include the gpio_led driver in the U-Boot binary.
2165
2166		CONFIG_GPIO_LED_INVERTED_TABLE
2167		Some GPIO connected LEDs may have inverted polarity in which
2168		case the GPIO high value corresponds to LED off state and
2169		GPIO low value corresponds to LED on state.
2170		In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2171		with a list of GPIO LEDs that have inverted polarity.
2172
2173- CAN Support:	CONFIG_CAN_DRIVER
2174
2175		Defining CONFIG_CAN_DRIVER enables CAN driver support
2176		on those systems that support this (optional)
2177		feature, like the TQM8xxL modules.
2178
2179- I2C Support:	CONFIG_SYS_I2C
2180
2181		This enable the NEW i2c subsystem, and will allow you to use
2182		i2c commands at the u-boot command line (as long as you set
2183		CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2184		based realtime clock chips or other i2c devices. See
2185		common/cmd_i2c.c for a description of the command line
2186		interface.
2187
2188		ported i2c driver to the new framework:
2189		- drivers/i2c/soft_i2c.c:
2190		  - activate first bus with CONFIG_SYS_I2C_SOFT define
2191		    CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2192		    for defining speed and slave address
2193		  - activate second bus with I2C_SOFT_DECLARATIONS2 define
2194		    CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2195		    for defining speed and slave address
2196		  - activate third bus with I2C_SOFT_DECLARATIONS3 define
2197		    CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2198		    for defining speed and slave address
2199		  - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2200		    CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2201		    for defining speed and slave address
2202
2203		- drivers/i2c/fsl_i2c.c:
2204		  - activate i2c driver with CONFIG_SYS_I2C_FSL
2205		    define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2206		    offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2207		    CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2208		    bus.
2209		  - If your board supports a second fsl i2c bus, define
2210		    CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2211		    CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2212		    CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2213		    second bus.
2214
2215		- drivers/i2c/tegra_i2c.c:
2216		  - activate this driver with CONFIG_SYS_I2C_TEGRA
2217		  - This driver adds 4 i2c buses with a fix speed from
2218		    100000 and the slave addr 0!
2219
2220		- drivers/i2c/ppc4xx_i2c.c
2221		  - activate this driver with CONFIG_SYS_I2C_PPC4XX
2222		  - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2223		  - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2224
2225		- drivers/i2c/i2c_mxc.c
2226		  - activate this driver with CONFIG_SYS_I2C_MXC
2227		  - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2228		  - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2229		  - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2230		  - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2231		  - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2232		  - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2233		If thoses defines are not set, default value is 100000
2234		for speed, and 0 for slave.
2235
2236		- drivers/i2c/rcar_i2c.c:
2237		  - activate this driver with CONFIG_SYS_I2C_RCAR
2238		  - This driver adds 4 i2c buses
2239
2240		  - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2241		  - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2242		  - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2243		  - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2244		  - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2245		  - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2246		  - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2247		  - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2248		  - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2249
2250		- drivers/i2c/sh_i2c.c:
2251		  - activate this driver with CONFIG_SYS_I2C_SH
2252		  - This driver adds from 2 to 5 i2c buses
2253
2254		  - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2255		  - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2256		  - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2257		  - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2258		  - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2259		  - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2260		  - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2261		  - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2262		  - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2263		  - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2264		  - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2265		  - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2266		  - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2267
2268		- drivers/i2c/omap24xx_i2c.c
2269		  - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2270		  - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2271		  - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2272		  - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2273		  - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2274		  - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2275		  - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2276		  - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2277		  - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2278		  - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2279		  - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2280
2281		- drivers/i2c/zynq_i2c.c
2282		  - activate this driver with CONFIG_SYS_I2C_ZYNQ
2283		  - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2284		  - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2285
2286		- drivers/i2c/s3c24x0_i2c.c:
2287		  - activate this driver with CONFIG_SYS_I2C_S3C24X0
2288		  - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2289		    9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2290		    with a fix speed from 100000 and the slave addr 0!
2291
2292		- drivers/i2c/ihs_i2c.c
2293		  - activate this driver with CONFIG_SYS_I2C_IHS
2294		  - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2295		  - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2296		  - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2297		  - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2298		  - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2299		  - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2300		  - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2301		  - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2302		  - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2303		  - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2304		  - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2305		  - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2306
2307		additional defines:
2308
2309		CONFIG_SYS_NUM_I2C_BUSES
2310		Hold the number of i2c busses you want to use. If you
2311		don't use/have i2c muxes on your i2c bus, this
2312		is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2313		omit this define.
2314
2315		CONFIG_SYS_I2C_DIRECT_BUS
2316		define this, if you don't use i2c muxes on your hardware.
2317		if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2318		omit this define.
2319
2320		CONFIG_SYS_I2C_MAX_HOPS
2321		define how many muxes are maximal consecutively connected
2322		on one i2c bus. If you not use i2c muxes, omit this
2323		define.
2324
2325		CONFIG_SYS_I2C_BUSES
2326		hold a list of busses you want to use, only used if
2327		CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2328		a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2329		CONFIG_SYS_NUM_I2C_BUSES = 9:
2330
2331		 CONFIG_SYS_I2C_BUSES	{{0, {I2C_NULL_HOP}}, \
2332					{0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2333					{0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2334					{0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2335					{0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2336					{0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2337					{1, {I2C_NULL_HOP}}, \
2338					{1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2339					{1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2340					}
2341
2342		which defines
2343			bus 0 on adapter 0 without a mux
2344			bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2345			bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2346			bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2347			bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2348			bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2349			bus 6 on adapter 1 without a mux
2350			bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2351			bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2352
2353		If you do not have i2c muxes on your board, omit this define.
2354
2355- Legacy I2C Support:	CONFIG_HARD_I2C
2356
2357		NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2358		provides the following compelling advantages:
2359
2360		- more than one i2c adapter is usable
2361		- approved multibus support
2362		- better i2c mux support
2363
2364		** Please consider updating your I2C driver now. **
2365
2366		These enable legacy I2C serial bus commands. Defining
2367		CONFIG_HARD_I2C will include the appropriate I2C driver
2368		for the selected CPU.
2369
2370		This will allow you to use i2c commands at the u-boot
2371		command line (as long as you set CONFIG_CMD_I2C in
2372		CONFIG_COMMANDS) and communicate with i2c based realtime
2373		clock chips. See common/cmd_i2c.c for a description of the
2374		command line interface.
2375
2376		CONFIG_HARD_I2C selects a hardware I2C controller.
2377
2378		There are several other quantities that must also be
2379		defined when you define CONFIG_HARD_I2C.
2380
2381		In both cases you will need to define CONFIG_SYS_I2C_SPEED
2382		to be the frequency (in Hz) at which you wish your i2c bus
2383		to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2384		the CPU's i2c node address).
2385
2386		Now, the u-boot i2c code for the mpc8xx
2387		(arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2388		and so its address should therefore be cleared to 0 (See,
2389		eg, MPC823e User's Manual p.16-473). So, set
2390		CONFIG_SYS_I2C_SLAVE to 0.
2391
2392		CONFIG_SYS_I2C_INIT_MPC5XXX
2393
2394		When a board is reset during an i2c bus transfer
2395		chips might think that the current transfer is still
2396		in progress.  Reset the slave devices by sending start
2397		commands until the slave device responds.
2398
2399		That's all that's required for CONFIG_HARD_I2C.
2400
2401		If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2402		then the following macros need to be defined (examples are
2403		from include/configs/lwmon.h):
2404
2405		I2C_INIT
2406
2407		(Optional). Any commands necessary to enable the I2C
2408		controller or configure ports.
2409
2410		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)
2411
2412		I2C_PORT
2413
2414		(Only for MPC8260 CPU). The I/O port to use (the code
2415		assumes both bits are on the same port). Valid values
2416		are 0..3 for ports A..D.
2417
2418		I2C_ACTIVE
2419
2420		The code necessary to make the I2C data line active
2421		(driven).  If the data line is open collector, this
2422		define can be null.
2423
2424		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
2425
2426		I2C_TRISTATE
2427
2428		The code necessary to make the I2C data line tri-stated
2429		(inactive).  If the data line is open collector, this
2430		define can be null.
2431
2432		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2433
2434		I2C_READ
2435
2436		Code that returns true if the I2C data line is high,
2437		false if it is low.
2438
2439		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2440
2441		I2C_SDA(bit)
2442
2443		If <bit> is true, sets the I2C data line high. If it
2444		is false, it clears it (low).
2445
2446		eg: #define I2C_SDA(bit) \
2447			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
2448			else	immr->im_cpm.cp_pbdat &= ~PB_SDA
2449
2450		I2C_SCL(bit)
2451
2452		If <bit> is true, sets the I2C clock line high. If it
2453		is false, it clears it (low).
2454
2455		eg: #define I2C_SCL(bit) \
2456			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
2457			else	immr->im_cpm.cp_pbdat &= ~PB_SCL
2458
2459		I2C_DELAY
2460
2461		This delay is invoked four times per clock cycle so this
2462		controls the rate of data transfer.  The data rate thus
2463		is 1 / (I2C_DELAY * 4). Often defined to be something
2464		like:
2465
2466		#define I2C_DELAY  udelay(2)
2467
2468		CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2469
2470		If your arch supports the generic GPIO framework (asm/gpio.h),
2471		then you may alternatively define the two GPIOs that are to be
2472		used as SCL / SDA.  Any of the previous I2C_xxx macros will
2473		have GPIO-based defaults assigned to them as appropriate.
2474
2475		You should define these to the GPIO value as given directly to
2476		the generic GPIO functions.
2477
2478		CONFIG_SYS_I2C_INIT_BOARD
2479
2480		When a board is reset during an i2c bus transfer
2481		chips might think that the current transfer is still
2482		in progress. On some boards it is possible to access
2483		the i2c SCLK line directly, either by using the
2484		processor pin as a GPIO or by having a second pin
2485		connected to the bus. If this option is defined a
2486		custom i2c_init_board() routine in boards/xxx/board.c
2487		is run early in the boot sequence.
2488
2489		CONFIG_SYS_I2C_BOARD_LATE_INIT
2490
2491		An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2492		defined a custom i2c_board_late_init() routine in
2493		boards/xxx/board.c is run AFTER the operations in i2c_init()
2494		is completed. This callpoint can be used to unreset i2c bus
2495		using CPU i2c controller register accesses for CPUs whose i2c
2496		controller provide such a method. It is called at the end of
2497		i2c_init() to allow i2c_init operations to setup the i2c bus
2498		controller on the CPU (e.g. setting bus speed & slave address).
2499
2500		CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2501
2502		This option enables configuration of bi_iic_fast[] flags
2503		in u-boot bd_info structure based on u-boot environment
2504		variable "i2cfast". (see also i2cfast)
2505
2506		CONFIG_I2C_MULTI_BUS
2507
2508		This option allows the use of multiple I2C buses, each of which
2509		must have a controller.	 At any point in time, only one bus is
2510		active.	 To switch to a different bus, use the 'i2c dev' command.
2511		Note that bus numbering is zero-based.
2512
2513		CONFIG_SYS_I2C_NOPROBES
2514
2515		This option specifies a list of I2C devices that will be skipped
2516		when the 'i2c probe' command is issued.	 If CONFIG_I2C_MULTI_BUS
2517		is set, specify a list of bus-device pairs.  Otherwise, specify
2518		a 1D array of device addresses
2519
2520		e.g.
2521			#undef	CONFIG_I2C_MULTI_BUS
2522			#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2523
2524		will skip addresses 0x50 and 0x68 on a board with one I2C bus
2525
2526			#define CONFIG_I2C_MULTI_BUS
2527			#define CONFIG_SYS_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
2528
2529		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2530
2531		CONFIG_SYS_SPD_BUS_NUM
2532
2533		If defined, then this indicates the I2C bus number for DDR SPD.
2534		If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2535
2536		CONFIG_SYS_RTC_BUS_NUM
2537
2538		If defined, then this indicates the I2C bus number for the RTC.
2539		If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2540
2541		CONFIG_SYS_DTT_BUS_NUM
2542
2543		If defined, then this indicates the I2C bus number for the DTT.
2544		If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2545
2546		CONFIG_SYS_I2C_DTT_ADDR:
2547
2548		If defined, specifies the I2C address of the DTT device.
2549		If not defined, then U-Boot uses predefined value for
2550		specified DTT device.
2551
2552		CONFIG_SOFT_I2C_READ_REPEATED_START
2553
2554		defining this will force the i2c_read() function in
2555		the soft_i2c driver to perform an I2C repeated start
2556		between writing the address pointer and reading the
2557		data.  If this define is omitted the default behaviour
2558		of doing a stop-start sequence will be used.  Most I2C
2559		devices can use either method, but some require one or
2560		the other.
2561
2562- SPI Support:	CONFIG_SPI
2563
2564		Enables SPI driver (so far only tested with
2565		SPI EEPROM, also an instance works with Crystal A/D and
2566		D/As on the SACSng board)
2567
2568		CONFIG_SH_SPI
2569
2570		Enables the driver for SPI controller on SuperH. Currently
2571		only SH7757 is supported.
2572
2573		CONFIG_SPI_X
2574
2575		Enables extended (16-bit) SPI EEPROM addressing.
2576		(symmetrical to CONFIG_I2C_X)
2577
2578		CONFIG_SOFT_SPI
2579
2580		Enables a software (bit-bang) SPI driver rather than
2581		using hardware support. This is a general purpose
2582		driver that only requires three general I/O port pins
2583		(two outputs, one input) to function. If this is
2584		defined, the board configuration must define several
2585		SPI configuration items (port pins to use, etc). For
2586		an example, see include/configs/sacsng.h.
2587
2588		CONFIG_HARD_SPI
2589
2590		Enables a hardware SPI driver for general-purpose reads
2591		and writes.  As with CONFIG_SOFT_SPI, the board configuration
2592		must define a list of chip-select function pointers.
2593		Currently supported on some MPC8xxx processors.	 For an
2594		example, see include/configs/mpc8349emds.h.
2595
2596		CONFIG_MXC_SPI
2597
2598		Enables the driver for the SPI controllers on i.MX and MXC
2599		SoCs. Currently i.MX31/35/51 are supported.
2600
2601		CONFIG_SYS_SPI_MXC_WAIT
2602		Timeout for waiting until spi transfer completed.
2603		default: (CONFIG_SYS_HZ/100)     /* 10 ms */
2604
2605- FPGA Support: CONFIG_FPGA
2606
2607		Enables FPGA subsystem.
2608
2609		CONFIG_FPGA_<vendor>
2610
2611		Enables support for specific chip vendors.
2612		(ALTERA, XILINX)
2613
2614		CONFIG_FPGA_<family>
2615
2616		Enables support for FPGA family.
2617		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2618
2619		CONFIG_FPGA_COUNT
2620
2621		Specify the number of FPGA devices to support.
2622
2623		CONFIG_CMD_FPGA_LOADMK
2624
2625		Enable support for fpga loadmk command
2626
2627		CONFIG_CMD_FPGA_LOADP
2628
2629		Enable support for fpga loadp command - load partial bitstream
2630
2631		CONFIG_CMD_FPGA_LOADBP
2632
2633		Enable support for fpga loadbp command - load partial bitstream
2634		(Xilinx only)
2635
2636		CONFIG_SYS_FPGA_PROG_FEEDBACK
2637
2638		Enable printing of hash marks during FPGA configuration.
2639
2640		CONFIG_SYS_FPGA_CHECK_BUSY
2641
2642		Enable checks on FPGA configuration interface busy
2643		status by the configuration function. This option
2644		will require a board or device specific function to
2645		be written.
2646
2647		CONFIG_FPGA_DELAY
2648
2649		If defined, a function that provides delays in the FPGA
2650		configuration driver.
2651
2652		CONFIG_SYS_FPGA_CHECK_CTRLC
2653		Allow Control-C to interrupt FPGA configuration
2654
2655		CONFIG_SYS_FPGA_CHECK_ERROR
2656
2657		Check for configuration errors during FPGA bitfile
2658		loading. For example, abort during Virtex II
2659		configuration if the INIT_B line goes low (which
2660		indicated a CRC error).
2661
2662		CONFIG_SYS_FPGA_WAIT_INIT
2663
2664		Maximum time to wait for the INIT_B line to deassert
2665		after PROB_B has been deasserted during a Virtex II
2666		FPGA configuration sequence. The default time is 500
2667		ms.
2668
2669		CONFIG_SYS_FPGA_WAIT_BUSY
2670
2671		Maximum time to wait for BUSY to deassert during
2672		Virtex II FPGA configuration. The default is 5 ms.
2673
2674		CONFIG_SYS_FPGA_WAIT_CONFIG
2675
2676		Time to wait after FPGA configuration. The default is
2677		200 ms.
2678
2679- Configuration Management:
2680		CONFIG_IDENT_STRING
2681
2682		If defined, this string will be added to the U-Boot
2683		version information (U_BOOT_VERSION)
2684
2685- Vendor Parameter Protection:
2686
2687		U-Boot considers the values of the environment
2688		variables "serial#" (Board Serial Number) and
2689		"ethaddr" (Ethernet Address) to be parameters that
2690		are set once by the board vendor / manufacturer, and
2691		protects these variables from casual modification by
2692		the user. Once set, these variables are read-only,
2693		and write or delete attempts are rejected. You can
2694		change this behaviour:
2695
2696		If CONFIG_ENV_OVERWRITE is #defined in your config
2697		file, the write protection for vendor parameters is
2698		completely disabled. Anybody can change or delete
2699		these parameters.
2700
2701		Alternatively, if you #define _both_ CONFIG_ETHADDR
2702		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2703		Ethernet address is installed in the environment,
2704		which can be changed exactly ONCE by the user. [The
2705		serial# is unaffected by this, i. e. it remains
2706		read-only.]
2707
2708		The same can be accomplished in a more flexible way
2709		for any variable by configuring the type of access
2710		to allow for those variables in the ".flags" variable
2711		or define CONFIG_ENV_FLAGS_LIST_STATIC.
2712
2713- Protected RAM:
2714		CONFIG_PRAM
2715
2716		Define this variable to enable the reservation of
2717		"protected RAM", i. e. RAM which is not overwritten
2718		by U-Boot. Define CONFIG_PRAM to hold the number of
2719		kB you want to reserve for pRAM. You can overwrite
2720		this default value by defining an environment
2721		variable "pram" to the number of kB you want to
2722		reserve. Note that the board info structure will
2723		still show the full amount of RAM. If pRAM is
2724		reserved, a new environment variable "mem" will
2725		automatically be defined to hold the amount of
2726		remaining RAM in a form that can be passed as boot
2727		argument to Linux, for instance like that:
2728
2729			setenv bootargs ... mem=\${mem}
2730			saveenv
2731
2732		This way you can tell Linux not to use this memory,
2733		either, which results in a memory region that will
2734		not be affected by reboots.
2735
2736		*WARNING* If your board configuration uses automatic
2737		detection of the RAM size, you must make sure that
2738		this memory test is non-destructive. So far, the
2739		following board configurations are known to be
2740		"pRAM-clean":
2741
2742			IVMS8, IVML24, SPD8xx, TQM8xxL,
2743			HERMES, IP860, RPXlite, LWMON,
2744			FLAGADM, TQM8260
2745
2746- Access to physical memory region (> 4GB)
2747		Some basic support is provided for operations on memory not
2748		normally accessible to U-Boot - e.g. some architectures
2749		support access to more than 4GB of memory on 32-bit
2750		machines using physical address extension or similar.
2751		Define CONFIG_PHYSMEM to access this basic support, which
2752		currently only supports clearing the memory.
2753
2754- Error Recovery:
2755		CONFIG_PANIC_HANG
2756
2757		Define this variable to stop the system in case of a
2758		fatal error, so that you have to reset it manually.
2759		This is probably NOT a good idea for an embedded
2760		system where you want the system to reboot
2761		automatically as fast as possible, but it may be
2762		useful during development since you can try to debug
2763		the conditions that lead to the situation.
2764
2765		CONFIG_NET_RETRY_COUNT
2766
2767		This variable defines the number of retries for
2768		network operations like ARP, RARP, TFTP, or BOOTP
2769		before giving up the operation. If not defined, a
2770		default value of 5 is used.
2771
2772		CONFIG_ARP_TIMEOUT
2773
2774		Timeout waiting for an ARP reply in milliseconds.
2775
2776		CONFIG_NFS_TIMEOUT
2777
2778		Timeout in milliseconds used in NFS protocol.
2779		If you encounter "ERROR: Cannot umount" in nfs command,
2780		try longer timeout such as
2781		#define CONFIG_NFS_TIMEOUT 10000UL
2782
2783- Command Interpreter:
2784		CONFIG_AUTO_COMPLETE
2785
2786		Enable auto completion of commands using TAB.
2787
2788		Note that this feature has NOT been implemented yet
2789		for the "hush" shell.
2790
2791
2792		CONFIG_SYS_HUSH_PARSER
2793
2794		Define this variable to enable the "hush" shell (from
2795		Busybox) as command line interpreter, thus enabling
2796		powerful command line syntax like
2797		if...then...else...fi conditionals or `&&' and '||'
2798		constructs ("shell scripts").
2799
2800		If undefined, you get the old, much simpler behaviour
2801		with a somewhat smaller memory footprint.
2802
2803
2804		CONFIG_SYS_PROMPT_HUSH_PS2
2805
2806		This defines the secondary prompt string, which is
2807		printed when the command interpreter needs more input
2808		to complete a command. Usually "> ".
2809
2810	Note:
2811
2812		In the current implementation, the local variables
2813		space and global environment variables space are
2814		separated. Local variables are those you define by
2815		simply typing `name=value'. To access a local
2816		variable later on, you have write `$name' or
2817		`${name}'; to execute the contents of a variable
2818		directly type `$name' at the command prompt.
2819
2820		Global environment variables are those you use
2821		setenv/printenv to work with. To run a command stored
2822		in such a variable, you need to use the run command,
2823		and you must not use the '$' sign to access them.
2824
2825		To store commands and special characters in a
2826		variable, please use double quotation marks
2827		surrounding the whole text of the variable, instead
2828		of the backslashes before semicolons and special
2829		symbols.
2830
2831- Commandline Editing and History:
2832		CONFIG_CMDLINE_EDITING
2833
2834		Enable editing and History functions for interactive
2835		commandline input operations
2836
2837- Default Environment:
2838		CONFIG_EXTRA_ENV_SETTINGS
2839
2840		Define this to contain any number of null terminated
2841		strings (variable = value pairs) that will be part of
2842		the default environment compiled into the boot image.
2843
2844		For example, place something like this in your
2845		board's config file:
2846
2847		#define CONFIG_EXTRA_ENV_SETTINGS \
2848			"myvar1=value1\0" \
2849			"myvar2=value2\0"
2850
2851		Warning: This method is based on knowledge about the
2852		internal format how the environment is stored by the
2853		U-Boot code. This is NOT an official, exported
2854		interface! Although it is unlikely that this format
2855		will change soon, there is no guarantee either.
2856		You better know what you are doing here.
2857
2858		Note: overly (ab)use of the default environment is
2859		discouraged. Make sure to check other ways to preset
2860		the environment like the "source" command or the
2861		boot command first.
2862
2863		CONFIG_ENV_VARS_UBOOT_CONFIG
2864
2865		Define this in order to add variables describing the
2866		U-Boot build configuration to the default environment.
2867		These will be named arch, cpu, board, vendor, and soc.
2868
2869		Enabling this option will cause the following to be defined:
2870
2871		- CONFIG_SYS_ARCH
2872		- CONFIG_SYS_CPU
2873		- CONFIG_SYS_BOARD
2874		- CONFIG_SYS_VENDOR
2875		- CONFIG_SYS_SOC
2876
2877		CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2878
2879		Define this in order to add variables describing certain
2880		run-time determined information about the hardware to the
2881		environment.  These will be named board_name, board_rev.
2882
2883		CONFIG_DELAY_ENVIRONMENT
2884
2885		Normally the environment is loaded when the board is
2886		intialised so that it is available to U-Boot. This inhibits
2887		that so that the environment is not available until
2888		explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2889		this is instead controlled by the value of
2890		/config/load-environment.
2891
2892- DataFlash Support:
2893		CONFIG_HAS_DATAFLASH
2894
2895		Defining this option enables DataFlash features and
2896		allows to read/write in Dataflash via the standard
2897		commands cp, md...
2898
2899- Serial Flash support
2900		CONFIG_CMD_SF
2901
2902		Defining this option enables SPI flash commands
2903		'sf probe/read/write/erase/update'.
2904
2905		Usage requires an initial 'probe' to define the serial
2906		flash parameters, followed by read/write/erase/update
2907		commands.
2908
2909		The following defaults may be provided by the platform
2910		to handle the common case when only a single serial
2911		flash is present on the system.
2912
2913		CONFIG_SF_DEFAULT_BUS		Bus identifier
2914		CONFIG_SF_DEFAULT_CS		Chip-select
2915		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
2916		CONFIG_SF_DEFAULT_SPEED		in Hz
2917
2918		CONFIG_CMD_SF_TEST
2919
2920		Define this option to include a destructive SPI flash
2921		test ('sf test').
2922
2923		CONFIG_SPI_FLASH_BAR		Ban/Extended Addr Reg
2924
2925		Define this option to use the Bank addr/Extended addr
2926		support on SPI flashes which has size > 16Mbytes.
2927
2928		CONFIG_SF_DUAL_FLASH		Dual flash memories
2929
2930		Define this option to use dual flash support where two flash
2931		memories can be connected with a given cs line.
2932		currently Xilinx Zynq qspi support these type of connections.
2933
2934- SystemACE Support:
2935		CONFIG_SYSTEMACE
2936
2937		Adding this option adds support for Xilinx SystemACE
2938		chips attached via some sort of local bus. The address
2939		of the chip must also be defined in the
2940		CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2941
2942		#define CONFIG_SYSTEMACE
2943		#define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2944
2945		When SystemACE support is added, the "ace" device type
2946		becomes available to the fat commands, i.e. fatls.
2947
2948- TFTP Fixed UDP Port:
2949		CONFIG_TFTP_PORT
2950
2951		If this is defined, the environment variable tftpsrcp
2952		is used to supply the TFTP UDP source port value.
2953		If tftpsrcp isn't defined, the normal pseudo-random port
2954		number generator is used.
2955
2956		Also, the environment variable tftpdstp is used to supply
2957		the TFTP UDP destination port value.  If tftpdstp isn't
2958		defined, the normal port 69 is used.
2959
2960		The purpose for tftpsrcp is to allow a TFTP server to
2961		blindly start the TFTP transfer using the pre-configured
2962		target IP address and UDP port. This has the effect of
2963		"punching through" the (Windows XP) firewall, allowing
2964		the remainder of the TFTP transfer to proceed normally.
2965		A better solution is to properly configure the firewall,
2966		but sometimes that is not allowed.
2967
2968- Hashing support:
2969		CONFIG_CMD_HASH
2970
2971		This enables a generic 'hash' command which can produce
2972		hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2973
2974		CONFIG_HASH_VERIFY
2975
2976		Enable the hash verify command (hash -v). This adds to code
2977		size a little.
2978
2979		CONFIG_SHA1 - support SHA1 hashing
2980		CONFIG_SHA256 - support SHA256 hashing
2981
2982		Note: There is also a sha1sum command, which should perhaps
2983		be deprecated in favour of 'hash sha1'.
2984
2985- Freescale i.MX specific commands:
2986		CONFIG_CMD_HDMIDETECT
2987		This enables 'hdmidet' command which returns true if an
2988		HDMI monitor is detected.  This command is i.MX 6 specific.
2989
2990		CONFIG_CMD_BMODE
2991		This enables the 'bmode' (bootmode) command for forcing
2992		a boot from specific media.
2993
2994		This is useful for forcing the ROM's usb downloader to
2995		activate upon a watchdog reset which is nice when iterating
2996		on U-Boot.  Using the reset button or running bmode normal
2997		will set it back to normal.  This command currently
2998		supports i.MX53 and i.MX6.
2999
3000- Signing support:
3001		CONFIG_RSA
3002
3003		This enables the RSA algorithm used for FIT image verification
3004		in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3005
3006		The signing part is build into mkimage regardless of this
3007		option.
3008
3009- bootcount support:
3010		CONFIG_BOOTCOUNT_LIMIT
3011
3012		This enables the bootcounter support, see:
3013		http://www.denx.de/wiki/DULG/UBootBootCountLimit
3014
3015		CONFIG_AT91SAM9XE
3016		enable special bootcounter support on at91sam9xe based boards.
3017		CONFIG_BLACKFIN
3018		enable special bootcounter support on blackfin based boards.
3019		CONFIG_SOC_DA8XX
3020		enable special bootcounter support on da850 based boards.
3021		CONFIG_BOOTCOUNT_RAM
3022		enable support for the bootcounter in RAM
3023		CONFIG_BOOTCOUNT_I2C
3024		enable support for the bootcounter on an i2c (like RTC) device.
3025			CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3026			CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3027						    the bootcounter.
3028			CONFIG_BOOTCOUNT_ALEN = address len
3029
3030- Show boot progress:
3031		CONFIG_SHOW_BOOT_PROGRESS
3032
3033		Defining this option allows to add some board-
3034		specific code (calling a user-provided function
3035		"show_boot_progress(int)") that enables you to show
3036		the system's boot progress on some display (for
3037		example, some LED's) on your board. At the moment,
3038		the following checkpoints are implemented:
3039
3040- Detailed boot stage timing
3041		CONFIG_BOOTSTAGE
3042		Define this option to get detailed timing of each stage
3043		of the boot process.
3044
3045		CONFIG_BOOTSTAGE_USER_COUNT
3046		This is the number of available user bootstage records.
3047		Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3048		a new ID will be allocated from this stash. If you exceed
3049		the limit, recording will stop.
3050
3051		CONFIG_BOOTSTAGE_REPORT
3052		Define this to print a report before boot, similar to this:
3053
3054		Timer summary in microseconds:
3055		       Mark    Elapsed  Stage
3056			  0          0  reset
3057		  3,575,678  3,575,678  board_init_f start
3058		  3,575,695         17  arch_cpu_init A9
3059		  3,575,777         82  arch_cpu_init done
3060		  3,659,598     83,821  board_init_r start
3061		  3,910,375    250,777  main_loop
3062		 29,916,167 26,005,792  bootm_start
3063		 30,361,327    445,160  start_kernel
3064
3065		CONFIG_CMD_BOOTSTAGE
3066		Add a 'bootstage' command which supports printing a report
3067		and un/stashing of bootstage data.
3068
3069		CONFIG_BOOTSTAGE_FDT
3070		Stash the bootstage information in the FDT. A root 'bootstage'
3071		node is created with each bootstage id as a child. Each child
3072		has a 'name' property and either 'mark' containing the
3073		mark time in microsecond, or 'accum' containing the
3074		accumulated time for that bootstage id in microseconds.
3075		For example:
3076
3077		bootstage {
3078			154 {
3079				name = "board_init_f";
3080				mark = <3575678>;
3081			};
3082			170 {
3083				name = "lcd";
3084				accum = <33482>;
3085			};
3086		};
3087
3088		Code in the Linux kernel can find this in /proc/devicetree.
3089
3090Legacy uImage format:
3091
3092  Arg	Where			When
3093    1	common/cmd_bootm.c	before attempting to boot an image
3094   -1	common/cmd_bootm.c	Image header has bad	 magic number
3095    2	common/cmd_bootm.c	Image header has correct magic number
3096   -2	common/cmd_bootm.c	Image header has bad	 checksum
3097    3	common/cmd_bootm.c	Image header has correct checksum
3098   -3	common/cmd_bootm.c	Image data   has bad	 checksum
3099    4	common/cmd_bootm.c	Image data   has correct checksum
3100   -4	common/cmd_bootm.c	Image is for unsupported architecture
3101    5	common/cmd_bootm.c	Architecture check OK
3102   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
3103    6	common/cmd_bootm.c	Image Type check OK
3104   -6	common/cmd_bootm.c	gunzip uncompression error
3105   -7	common/cmd_bootm.c	Unimplemented compression type
3106    7	common/cmd_bootm.c	Uncompression OK
3107    8	common/cmd_bootm.c	No uncompress/copy overwrite error
3108   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
3109
3110    9	common/image.c		Start initial ramdisk verification
3111  -10	common/image.c		Ramdisk header has bad	   magic number
3112  -11	common/image.c		Ramdisk header has bad	   checksum
3113   10	common/image.c		Ramdisk header is OK
3114  -12	common/image.c		Ramdisk data   has bad	   checksum
3115   11	common/image.c		Ramdisk data   has correct checksum
3116   12	common/image.c		Ramdisk verification complete, start loading
3117  -13	common/image.c		Wrong Image Type (not PPC Linux ramdisk)
3118   13	common/image.c		Start multifile image verification
3119   14	common/image.c		No initial ramdisk, no multifile, continue.
3120
3121   15	arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3122
3123  -30	arch/powerpc/lib/board.c	Fatal error, hang the system
3124  -31	post/post.c		POST test failed, detected by post_output_backlog()
3125  -32	post/post.c		POST test failed, detected by post_run_single()
3126
3127   34	common/cmd_doc.c	before loading a Image from a DOC device
3128  -35	common/cmd_doc.c	Bad usage of "doc" command
3129   35	common/cmd_doc.c	correct usage of "doc" command
3130  -36	common/cmd_doc.c	No boot device
3131   36	common/cmd_doc.c	correct boot device
3132  -37	common/cmd_doc.c	Unknown Chip ID on boot device
3133   37	common/cmd_doc.c	correct chip ID found, device available
3134  -38	common/cmd_doc.c	Read Error on boot device
3135   38	common/cmd_doc.c	reading Image header from DOC device OK
3136  -39	common/cmd_doc.c	Image header has bad magic number
3137   39	common/cmd_doc.c	Image header has correct magic number
3138  -40	common/cmd_doc.c	Error reading Image from DOC device
3139   40	common/cmd_doc.c	Image header has correct magic number
3140   41	common/cmd_ide.c	before loading a Image from a IDE device
3141  -42	common/cmd_ide.c	Bad usage of "ide" command
3142   42	common/cmd_ide.c	correct usage of "ide" command
3143  -43	common/cmd_ide.c	No boot device
3144   43	common/cmd_ide.c	boot device found
3145  -44	common/cmd_ide.c	Device not available
3146   44	common/cmd_ide.c	Device available
3147  -45	common/cmd_ide.c	wrong partition selected
3148   45	common/cmd_ide.c	partition selected
3149  -46	common/cmd_ide.c	Unknown partition table
3150   46	common/cmd_ide.c	valid partition table found
3151  -47	common/cmd_ide.c	Invalid partition type
3152   47	common/cmd_ide.c	correct partition type
3153  -48	common/cmd_ide.c	Error reading Image Header on boot device
3154   48	common/cmd_ide.c	reading Image Header from IDE device OK
3155  -49	common/cmd_ide.c	Image header has bad magic number
3156   49	common/cmd_ide.c	Image header has correct magic number
3157  -50	common/cmd_ide.c	Image header has bad	 checksum
3158   50	common/cmd_ide.c	Image header has correct checksum
3159  -51	common/cmd_ide.c	Error reading Image from IDE device
3160   51	common/cmd_ide.c	reading Image from IDE device OK
3161   52	common/cmd_nand.c	before loading a Image from a NAND device
3162  -53	common/cmd_nand.c	Bad usage of "nand" command
3163   53	common/cmd_nand.c	correct usage of "nand" command
3164  -54	common/cmd_nand.c	No boot device
3165   54	common/cmd_nand.c	boot device found
3166  -55	common/cmd_nand.c	Unknown Chip ID on boot device
3167   55	common/cmd_nand.c	correct chip ID found, device available
3168  -56	common/cmd_nand.c	Error reading Image Header on boot device
3169   56	common/cmd_nand.c	reading Image Header from NAND device OK
3170  -57	common/cmd_nand.c	Image header has bad magic number
3171   57	common/cmd_nand.c	Image header has correct magic number
3172  -58	common/cmd_nand.c	Error reading Image from NAND device
3173   58	common/cmd_nand.c	reading Image from NAND device OK
3174
3175  -60	common/env_common.c	Environment has a bad CRC, using default
3176
3177   64	net/eth.c		starting with Ethernet configuration.
3178  -64	net/eth.c		no Ethernet found.
3179   65	net/eth.c		Ethernet found.
3180
3181  -80	common/cmd_net.c	usage wrong
3182   80	common/cmd_net.c	before calling NetLoop()
3183  -81	common/cmd_net.c	some error in NetLoop() occurred
3184   81	common/cmd_net.c	NetLoop() back without error
3185  -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
3186   82	common/cmd_net.c	trying automatic boot
3187   83	common/cmd_net.c	running "source" command
3188  -83	common/cmd_net.c	some error in automatic boot or "source" command
3189   84	common/cmd_net.c	end without errors
3190
3191FIT uImage format:
3192
3193  Arg	Where			When
3194  100	common/cmd_bootm.c	Kernel FIT Image has correct format
3195 -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
3196  101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
3197 -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
3198  102	common/cmd_bootm.c	Kernel unit name specified
3199 -103	common/cmd_bootm.c	Can't get kernel subimage node offset
3200  103	common/cmd_bootm.c	Found configuration node
3201  104	common/cmd_bootm.c	Got kernel subimage node offset
3202 -104	common/cmd_bootm.c	Kernel subimage hash verification failed
3203  105	common/cmd_bootm.c	Kernel subimage hash verification OK
3204 -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
3205  106	common/cmd_bootm.c	Architecture check OK
3206 -106	common/cmd_bootm.c	Kernel subimage has wrong type
3207  107	common/cmd_bootm.c	Kernel subimage type OK
3208 -107	common/cmd_bootm.c	Can't get kernel subimage data/size
3209  108	common/cmd_bootm.c	Got kernel subimage data/size
3210 -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
3211 -109	common/cmd_bootm.c	Can't get kernel subimage type
3212 -110	common/cmd_bootm.c	Can't get kernel subimage comp
3213 -111	common/cmd_bootm.c	Can't get kernel subimage os
3214 -112	common/cmd_bootm.c	Can't get kernel subimage load address
3215 -113	common/cmd_bootm.c	Image uncompress/copy overwrite error
3216
3217  120	common/image.c		Start initial ramdisk verification
3218 -120	common/image.c		Ramdisk FIT image has incorrect format
3219  121	common/image.c		Ramdisk FIT image has correct format
3220  122	common/image.c		No ramdisk subimage unit name, using configuration
3221 -122	common/image.c		Can't get configuration for ramdisk subimage
3222  123	common/image.c		Ramdisk unit name specified
3223 -124	common/image.c		Can't get ramdisk subimage node offset
3224  125	common/image.c		Got ramdisk subimage node offset
3225 -125	common/image.c		Ramdisk subimage hash verification failed
3226  126	common/image.c		Ramdisk subimage hash verification OK
3227 -126	common/image.c		Ramdisk subimage for unsupported architecture
3228  127	common/image.c		Architecture check OK
3229 -127	common/image.c		Can't get ramdisk subimage data/size
3230  128	common/image.c		Got ramdisk subimage data/size
3231  129	common/image.c		Can't get ramdisk load address
3232 -129	common/image.c		Got ramdisk load address
3233
3234 -130	common/cmd_doc.c	Incorrect FIT image format
3235  131	common/cmd_doc.c	FIT image format OK
3236
3237 -140	common/cmd_ide.c	Incorrect FIT image format
3238  141	common/cmd_ide.c	FIT image format OK
3239
3240 -150	common/cmd_nand.c	Incorrect FIT image format
3241  151	common/cmd_nand.c	FIT image format OK
3242
3243- legacy image format:
3244		CONFIG_IMAGE_FORMAT_LEGACY
3245		enables the legacy image format support in U-Boot.
3246
3247		Default:
3248		enabled if CONFIG_FIT_SIGNATURE is not defined.
3249
3250		CONFIG_DISABLE_IMAGE_LEGACY
3251		disable the legacy image format
3252
3253		This define is introduced, as the legacy image format is
3254		enabled per default for backward compatibility.
3255
3256- FIT image support:
3257		CONFIG_FIT
3258		Enable support for the FIT uImage format.
3259
3260		CONFIG_FIT_BEST_MATCH
3261		When no configuration is explicitly selected, default to the
3262		one whose fdt's compatibility field best matches that of
3263		U-Boot itself. A match is considered "best" if it matches the
3264		most specific compatibility entry of U-Boot's fdt's root node.
3265		The order of entries in the configuration's fdt is ignored.
3266
3267		CONFIG_FIT_SIGNATURE
3268		This option enables signature verification of FIT uImages,
3269		using a hash signed and verified using RSA. See
3270		doc/uImage.FIT/signature.txt for more details.
3271
3272		WARNING: When relying on signed FIT images with required
3273		signature check the legacy image format is default
3274		disabled. If a board need legacy image format support
3275		enable this through CONFIG_IMAGE_FORMAT_LEGACY
3276
3277		CONFIG_FIT_DISABLE_SHA256
3278		Supporting SHA256 hashes has quite an impact on binary size.
3279		For constrained systems sha256 hash support can be disabled
3280		with this option.
3281
3282- Standalone program support:
3283		CONFIG_STANDALONE_LOAD_ADDR
3284
3285		This option defines a board specific value for the
3286		address where standalone program gets loaded, thus
3287		overwriting the architecture dependent default
3288		settings.
3289
3290- Frame Buffer Address:
3291		CONFIG_FB_ADDR
3292
3293		Define CONFIG_FB_ADDR if you want to use specific
3294		address for frame buffer.  This is typically the case
3295		when using a graphics controller has separate video
3296		memory.  U-Boot will then place the frame buffer at
3297		the given address instead of dynamically reserving it
3298		in system RAM by calling lcd_setmem(), which grabs
3299		the memory for the frame buffer depending on the
3300		configured panel size.
3301
3302		Please see board_init_f function.
3303
3304- Automatic software updates via TFTP server
3305		CONFIG_UPDATE_TFTP
3306		CONFIG_UPDATE_TFTP_CNT_MAX
3307		CONFIG_UPDATE_TFTP_MSEC_MAX
3308
3309		These options enable and control the auto-update feature;
3310		for a more detailed description refer to doc/README.update.
3311
3312- MTD Support (mtdparts command, UBI support)
3313		CONFIG_MTD_DEVICE
3314
3315		Adds the MTD device infrastructure from the Linux kernel.
3316		Needed for mtdparts command support.
3317
3318		CONFIG_MTD_PARTITIONS
3319
3320		Adds the MTD partitioning infrastructure from the Linux
3321		kernel. Needed for UBI support.
3322
3323- UBI support
3324		CONFIG_CMD_UBI
3325
3326		Adds commands for interacting with MTD partitions formatted
3327		with the UBI flash translation layer
3328
3329		Requires also defining CONFIG_RBTREE
3330
3331		CONFIG_UBI_SILENCE_MSG
3332
3333		Make the verbose messages from UBI stop printing.  This leaves
3334		warnings and errors enabled.
3335
3336- UBIFS support
3337		CONFIG_CMD_UBIFS
3338
3339		Adds commands for interacting with UBI volumes formatted as
3340		UBIFS.  UBIFS is read-only in u-boot.
3341
3342		Requires UBI support as well as CONFIG_LZO
3343
3344		CONFIG_UBIFS_SILENCE_MSG
3345
3346		Make the verbose messages from UBIFS stop printing.  This leaves
3347		warnings and errors enabled.
3348
3349- SPL framework
3350		CONFIG_SPL
3351		Enable building of SPL globally.
3352
3353		CONFIG_SPL_LDSCRIPT
3354		LDSCRIPT for linking the SPL binary.
3355
3356		CONFIG_SPL_MAX_FOOTPRINT
3357		Maximum size in memory allocated to the SPL, BSS included.
3358		When defined, the linker checks that the actual memory
3359		used by SPL from _start to __bss_end does not exceed it.
3360		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3361		must not be both defined at the same time.
3362
3363		CONFIG_SPL_MAX_SIZE
3364		Maximum size of the SPL image (text, data, rodata, and
3365		linker lists sections), BSS excluded.
3366		When defined, the linker checks that the actual size does
3367		not exceed it.
3368
3369		CONFIG_SPL_TEXT_BASE
3370		TEXT_BASE for linking the SPL binary.
3371
3372		CONFIG_SPL_RELOC_TEXT_BASE
3373		Address to relocate to.  If unspecified, this is equal to
3374		CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3375
3376		CONFIG_SPL_BSS_START_ADDR
3377		Link address for the BSS within the SPL binary.
3378
3379		CONFIG_SPL_BSS_MAX_SIZE
3380		Maximum size in memory allocated to the SPL BSS.
3381		When defined, the linker checks that the actual memory used
3382		by SPL from __bss_start to __bss_end does not exceed it.
3383		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3384		must not be both defined at the same time.
3385
3386		CONFIG_SPL_STACK
3387		Adress of the start of the stack SPL will use
3388
3389		CONFIG_SPL_RELOC_STACK
3390		Adress of the start of the stack SPL will use after
3391		relocation.  If unspecified, this is equal to
3392		CONFIG_SPL_STACK.
3393
3394		CONFIG_SYS_SPL_MALLOC_START
3395		Starting address of the malloc pool used in SPL.
3396
3397		CONFIG_SYS_SPL_MALLOC_SIZE
3398		The size of the malloc pool used in SPL.
3399
3400		CONFIG_SPL_FRAMEWORK
3401		Enable the SPL framework under common/.  This framework
3402		supports MMC, NAND and YMODEM loading of U-Boot and NAND
3403		NAND loading of the Linux Kernel.
3404
3405		CONFIG_SPL_OS_BOOT
3406		Enable booting directly to an OS from SPL.
3407		See also: doc/README.falcon
3408
3409		CONFIG_SPL_DISPLAY_PRINT
3410		For ARM, enable an optional function to print more information
3411		about the running system.
3412
3413		CONFIG_SPL_INIT_MINIMAL
3414		Arch init code should be built for a very small image
3415
3416		CONFIG_SPL_LIBCOMMON_SUPPORT
3417		Support for common/libcommon.o in SPL binary
3418
3419		CONFIG_SPL_LIBDISK_SUPPORT
3420		Support for disk/libdisk.o in SPL binary
3421
3422		CONFIG_SPL_I2C_SUPPORT
3423		Support for drivers/i2c/libi2c.o in SPL binary
3424
3425		CONFIG_SPL_GPIO_SUPPORT
3426		Support for drivers/gpio/libgpio.o in SPL binary
3427
3428		CONFIG_SPL_MMC_SUPPORT
3429		Support for drivers/mmc/libmmc.o in SPL binary
3430
3431		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3432		CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3433		CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3434		Address, size and partition on the MMC to load U-Boot from
3435		when the MMC is being used in raw mode.
3436
3437		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3438		Sector to load kernel uImage from when MMC is being
3439		used in raw mode (for Falcon mode)
3440
3441		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3442		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3443		Sector and number of sectors to load kernel argument
3444		parameters from when MMC is being used in raw mode
3445		(for falcon mode)
3446
3447		CONFIG_SPL_FAT_SUPPORT
3448		Support for fs/fat/libfat.o in SPL binary
3449
3450		CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3451		Filename to read to load U-Boot when reading from FAT
3452
3453		CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3454		Filename to read to load kernel uImage when reading
3455		from FAT (for Falcon mode)
3456
3457		CONFIG_SPL_FAT_LOAD_ARGS_NAME
3458		Filename to read to load kernel argument parameters
3459		when reading from FAT (for Falcon mode)
3460
3461		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3462		Set this for NAND SPL on PPC mpc83xx targets, so that
3463		start.S waits for the rest of the SPL to load before
3464		continuing (the hardware starts execution after just
3465		loading the first page rather than the full 4K).
3466
3467		CONFIG_SPL_SKIP_RELOCATE
3468		Avoid SPL relocation
3469
3470		CONFIG_SPL_NAND_BASE
3471		Include nand_base.c in the SPL.  Requires
3472		CONFIG_SPL_NAND_DRIVERS.
3473
3474		CONFIG_SPL_NAND_DRIVERS
3475		SPL uses normal NAND drivers, not minimal drivers.
3476
3477		CONFIG_SPL_NAND_ECC
3478		Include standard software ECC in the SPL
3479
3480		CONFIG_SPL_NAND_SIMPLE
3481		Support for NAND boot using simple NAND drivers that
3482		expose the cmd_ctrl() interface.
3483
3484		CONFIG_SPL_MTD_SUPPORT
3485		Support for the MTD subsystem within SPL.  Useful for
3486		environment on NAND support within SPL.
3487
3488		CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3489		Set for the SPL on PPC mpc8xxx targets, support for
3490		drivers/ddr/fsl/libddr.o in SPL binary.
3491
3492		CONFIG_SPL_COMMON_INIT_DDR
3493		Set for common ddr init with serial presence detect in
3494		SPL binary.
3495
3496		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3497		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3498		CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3499		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3500		CONFIG_SYS_NAND_ECCBYTES
3501		Defines the size and behavior of the NAND that SPL uses
3502		to read U-Boot
3503
3504		CONFIG_SPL_NAND_BOOT
3505		Add support NAND boot
3506
3507		CONFIG_SYS_NAND_U_BOOT_OFFS
3508		Location in NAND to read U-Boot from
3509
3510		CONFIG_SYS_NAND_U_BOOT_DST
3511		Location in memory to load U-Boot to
3512
3513		CONFIG_SYS_NAND_U_BOOT_SIZE
3514		Size of image to load
3515
3516		CONFIG_SYS_NAND_U_BOOT_START
3517		Entry point in loaded image to jump to
3518
3519		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3520		Define this if you need to first read the OOB and then the
3521		data. This is used for example on davinci plattforms.
3522
3523		CONFIG_SPL_OMAP3_ID_NAND
3524		Support for an OMAP3-specific set of functions to return the
3525		ID and MFR of the first attached NAND chip, if present.
3526
3527		CONFIG_SPL_SERIAL_SUPPORT
3528		Support for drivers/serial/libserial.o in SPL binary
3529
3530		CONFIG_SPL_SPI_FLASH_SUPPORT
3531		Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3532
3533		CONFIG_SPL_SPI_SUPPORT
3534		Support for drivers/spi/libspi.o in SPL binary
3535
3536		CONFIG_SPL_RAM_DEVICE
3537		Support for running image already present in ram, in SPL binary
3538
3539		CONFIG_SPL_LIBGENERIC_SUPPORT
3540		Support for lib/libgeneric.o in SPL binary
3541
3542		CONFIG_SPL_ENV_SUPPORT
3543		Support for the environment operating in SPL binary
3544
3545		CONFIG_SPL_NET_SUPPORT
3546		Support for the net/libnet.o in SPL binary.
3547		It conflicts with SPL env from storage medium specified by
3548		CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3549
3550		CONFIG_SPL_PAD_TO
3551		Image offset to which the SPL should be padded before appending
3552		the SPL payload. By default, this is defined as
3553		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3554		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3555		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3556
3557		CONFIG_SPL_TARGET
3558		Final target image containing SPL and payload.  Some SPLs
3559		use an arch-specific makefile fragment instead, for
3560		example if more than one image needs to be produced.
3561
3562		CONFIG_FIT_SPL_PRINT
3563		Printing information about a FIT image adds quite a bit of
3564		code to SPL. So this is normally disabled in SPL. Use this
3565		option to re-enable it. This will affect the output of the
3566		bootm command when booting a FIT image.
3567
3568- TPL framework
3569		CONFIG_TPL
3570		Enable building of TPL globally.
3571
3572		CONFIG_TPL_PAD_TO
3573		Image offset to which the TPL should be padded before appending
3574		the TPL payload. By default, this is defined as
3575		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3576		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3577		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3578
3579Modem Support:
3580--------------
3581
3582[so far only for SMDK2400 boards]
3583
3584- Modem support enable:
3585		CONFIG_MODEM_SUPPORT
3586
3587- RTS/CTS Flow control enable:
3588		CONFIG_HWFLOW
3589
3590- Modem debug support:
3591		CONFIG_MODEM_SUPPORT_DEBUG
3592
3593		Enables debugging stuff (char screen[1024], dbg())
3594		for modem support. Useful only with BDI2000.
3595
3596- Interrupt support (PPC):
3597
3598		There are common interrupt_init() and timer_interrupt()
3599		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3600		for CPU specific initialization. interrupt_init_cpu()
3601		should set decrementer_count to appropriate value. If
3602		CPU resets decrementer automatically after interrupt
3603		(ppc4xx) it should set decrementer_count to zero.
3604		timer_interrupt() calls timer_interrupt_cpu() for CPU
3605		specific handling. If board has watchdog / status_led
3606		/ other_activity_monitor it works automatically from
3607		general timer_interrupt().
3608
3609- General:
3610
3611		In the target system modem support is enabled when a
3612		specific key (key combination) is pressed during
3613		power-on. Otherwise U-Boot will boot normally
3614		(autoboot). The key_pressed() function is called from
3615		board_init(). Currently key_pressed() is a dummy
3616		function, returning 1 and thus enabling modem
3617		initialization.
3618
3619		If there are no modem init strings in the
3620		environment, U-Boot proceed to autoboot; the
3621		previous output (banner, info printfs) will be
3622		suppressed, though.
3623
3624		See also: doc/README.Modem
3625
3626Board initialization settings:
3627------------------------------
3628
3629During Initialization u-boot calls a number of board specific functions
3630to allow the preparation of board specific prerequisites, e.g. pin setup
3631before drivers are initialized. To enable these callbacks the
3632following configuration macros have to be defined. Currently this is
3633architecture specific, so please check arch/your_architecture/lib/board.c
3634typically in board_init_f() and board_init_r().
3635
3636- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3637- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3638- CONFIG_BOARD_LATE_INIT: Call board_late_init()
3639- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3640
3641Configuration Settings:
3642-----------------------
3643
3644- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3645		Optionally it can be defined to support 64-bit memory commands.
3646
3647- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3648		undefine this when you're short of memory.
3649
3650- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3651		width of the commands listed in the 'help' command output.
3652
3653- CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
3654		prompt for user input.
3655
3656- CONFIG_SYS_CBSIZE:	Buffer size for input from the Console
3657
3658- CONFIG_SYS_PBSIZE:	Buffer size for Console output
3659
3660- CONFIG_SYS_MAXARGS:	max. Number of arguments accepted for monitor commands
3661
3662- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3663		the application (usually a Linux kernel) when it is
3664		booted
3665
3666- CONFIG_SYS_BAUDRATE_TABLE:
3667		List of legal baudrate settings for this board.
3668
3669- CONFIG_SYS_CONSOLE_INFO_QUIET
3670		Suppress display of console information at boot.
3671
3672- CONFIG_SYS_CONSOLE_IS_IN_ENV
3673		If the board specific function
3674			extern int overwrite_console (void);
3675		returns 1, the stdin, stderr and stdout are switched to the
3676		serial port, else the settings in the environment are used.
3677
3678- CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3679		Enable the call to overwrite_console().
3680
3681- CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3682		Enable overwrite of previous console environment settings.
3683
3684- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3685		Begin and End addresses of the area used by the
3686		simple memory test.
3687
3688- CONFIG_SYS_ALT_MEMTEST:
3689		Enable an alternate, more extensive memory test.
3690
3691- CONFIG_SYS_MEMTEST_SCRATCH:
3692		Scratch address used by the alternate memory test
3693		You only need to set this if address zero isn't writeable
3694
3695- CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3696		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3697		this specified memory area will get subtracted from the top
3698		(end) of RAM and won't get "touched" at all by U-Boot. By
3699		fixing up gd->ram_size the Linux kernel should gets passed
3700		the now "corrected" memory size and won't touch it either.
3701		This should work for arch/ppc and arch/powerpc. Only Linux
3702		board ports in arch/powerpc with bootwrapper support that
3703		recalculate the memory size from the SDRAM controller setup
3704		will have to get fixed in Linux additionally.
3705
3706		This option can be used as a workaround for the 440EPx/GRx
3707		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3708		be touched.
3709
3710		WARNING: Please make sure that this value is a multiple of
3711		the Linux page size (normally 4k). If this is not the case,
3712		then the end address of the Linux memory will be located at a
3713		non page size aligned address and this could cause major
3714		problems.
3715
3716- CONFIG_SYS_LOADS_BAUD_CHANGE:
3717		Enable temporary baudrate change while serial download
3718
3719- CONFIG_SYS_SDRAM_BASE:
3720		Physical start address of SDRAM. _Must_ be 0 here.
3721
3722- CONFIG_SYS_MBIO_BASE:
3723		Physical start address of Motherboard I/O (if using a
3724		Cogent motherboard)
3725
3726- CONFIG_SYS_FLASH_BASE:
3727		Physical start address of Flash memory.
3728
3729- CONFIG_SYS_MONITOR_BASE:
3730		Physical start address of boot monitor code (set by
3731		make config files to be same as the text base address
3732		(CONFIG_SYS_TEXT_BASE) used when linking) - same as
3733		CONFIG_SYS_FLASH_BASE when booting from flash.
3734
3735- CONFIG_SYS_MONITOR_LEN:
3736		Size of memory reserved for monitor code, used to
3737		determine _at_compile_time_ (!) if the environment is
3738		embedded within the U-Boot image, or in a separate
3739		flash sector.
3740
3741- CONFIG_SYS_MALLOC_LEN:
3742		Size of DRAM reserved for malloc() use.
3743
3744- CONFIG_SYS_MALLOC_F_LEN
3745		Size of the malloc() pool for use before relocation. If
3746		this is defined, then a very simple malloc() implementation
3747		will become available before relocation. The address is just
3748		below the global data, and the stack is moved down to make
3749		space.
3750
3751		This feature allocates regions with increasing addresses
3752		within the region. calloc() is supported, but realloc()
3753		is not available. free() is supported but does nothing.
3754		The memory will be freed (or in fact just forgotton) when
3755		U-Boot relocates itself.
3756
3757		Pre-relocation malloc() is only supported on sandbox
3758		at present but is fairly easy to enable for other archs.
3759
3760		Pre-relocation malloc() is only supported on ARM at present
3761		but is fairly easy to enable for other archs.
3762
3763- CONFIG_SYS_BOOTM_LEN:
3764		Normally compressed uImages are limited to an
3765		uncompressed size of 8 MBytes. If this is not enough,
3766		you can define CONFIG_SYS_BOOTM_LEN in your board config file
3767		to adjust this setting to your needs.
3768
3769- CONFIG_SYS_BOOTMAPSZ:
3770		Maximum size of memory mapped by the startup code of
3771		the Linux kernel; all data that must be processed by
3772		the Linux kernel (bd_info, boot arguments, FDT blob if
3773		used) must be put below this limit, unless "bootm_low"
3774		environment variable is defined and non-zero. In such case
3775		all data for the Linux kernel must be between "bootm_low"
3776		and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.	 The environment
3777		variable "bootm_mapsize" will override the value of
3778		CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
3779		then the value in "bootm_size" will be used instead.
3780
3781- CONFIG_SYS_BOOT_RAMDISK_HIGH:
3782		Enable initrd_high functionality.  If defined then the
3783		initrd_high feature is enabled and the bootm ramdisk subcommand
3784		is enabled.
3785
3786- CONFIG_SYS_BOOT_GET_CMDLINE:
3787		Enables allocating and saving kernel cmdline in space between
3788		"bootm_low" and "bootm_low" + BOOTMAPSZ.
3789
3790- CONFIG_SYS_BOOT_GET_KBD:
3791		Enables allocating and saving a kernel copy of the bd_info in
3792		space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3793
3794- CONFIG_SYS_MAX_FLASH_BANKS:
3795		Max number of Flash memory banks
3796
3797- CONFIG_SYS_MAX_FLASH_SECT:
3798		Max number of sectors on a Flash chip
3799
3800- CONFIG_SYS_FLASH_ERASE_TOUT:
3801		Timeout for Flash erase operations (in ms)
3802
3803- CONFIG_SYS_FLASH_WRITE_TOUT:
3804		Timeout for Flash write operations (in ms)
3805
3806- CONFIG_SYS_FLASH_LOCK_TOUT
3807		Timeout for Flash set sector lock bit operation (in ms)
3808
3809- CONFIG_SYS_FLASH_UNLOCK_TOUT
3810		Timeout for Flash clear lock bits operation (in ms)
3811
3812- CONFIG_SYS_FLASH_PROTECTION
3813		If defined, hardware flash sectors protection is used
3814		instead of U-Boot software protection.
3815
3816- CONFIG_SYS_DIRECT_FLASH_TFTP:
3817
3818		Enable TFTP transfers directly to flash memory;
3819		without this option such a download has to be
3820		performed in two steps: (1) download to RAM, and (2)
3821		copy from RAM to flash.
3822
3823		The two-step approach is usually more reliable, since
3824		you can check if the download worked before you erase
3825		the flash, but in some situations (when system RAM is
3826		too limited to allow for a temporary copy of the
3827		downloaded image) this option may be very useful.
3828
3829- CONFIG_SYS_FLASH_CFI:
3830		Define if the flash driver uses extra elements in the
3831		common flash structure for storing flash geometry.
3832
3833- CONFIG_FLASH_CFI_DRIVER
3834		This option also enables the building of the cfi_flash driver
3835		in the drivers directory
3836
3837- CONFIG_FLASH_CFI_MTD
3838		This option enables the building of the cfi_mtd driver
3839		in the drivers directory. The driver exports CFI flash
3840		to the MTD layer.
3841
3842- CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3843		Use buffered writes to flash.
3844
3845- CONFIG_FLASH_SPANSION_S29WS_N
3846		s29ws-n MirrorBit flash has non-standard addresses for buffered
3847		write commands.
3848
3849- CONFIG_SYS_FLASH_QUIET_TEST
3850		If this option is defined, the common CFI flash doesn't
3851		print it's warning upon not recognized FLASH banks. This
3852		is useful, if some of the configured banks are only
3853		optionally available.
3854
3855- CONFIG_FLASH_SHOW_PROGRESS
3856		If defined (must be an integer), print out countdown
3857		digits and dots.  Recommended value: 45 (9..1) for 80
3858		column displays, 15 (3..1) for 40 column displays.
3859
3860- CONFIG_FLASH_VERIFY
3861		If defined, the content of the flash (destination) is compared
3862		against the source after the write operation. An error message
3863		will be printed when the contents are not identical.
3864		Please note that this option is useless in nearly all cases,
3865		since such flash programming errors usually are detected earlier
3866		while unprotecting/erasing/programming. Please only enable
3867		this option if you really know what you are doing.
3868
3869- CONFIG_SYS_RX_ETH_BUFFER:
3870		Defines the number of Ethernet receive buffers. On some
3871		Ethernet controllers it is recommended to set this value
3872		to 8 or even higher (EEPRO100 or 405 EMAC), since all
3873		buffers can be full shortly after enabling the interface
3874		on high Ethernet traffic.
3875		Defaults to 4 if not defined.
3876
3877- CONFIG_ENV_MAX_ENTRIES
3878
3879	Maximum number of entries in the hash table that is used
3880	internally to store the environment settings. The default
3881	setting is supposed to be generous and should work in most
3882	cases. This setting can be used to tune behaviour; see
3883	lib/hashtable.c for details.
3884
3885- CONFIG_ENV_FLAGS_LIST_DEFAULT
3886- CONFIG_ENV_FLAGS_LIST_STATIC
3887	Enable validation of the values given to environment variables when
3888	calling env set.  Variables can be restricted to only decimal,
3889	hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
3890	the variables can also be restricted to IP address or MAC address.
3891
3892	The format of the list is:
3893		type_attribute = [s|d|x|b|i|m]
3894		access_atribute = [a|r|o|c]
3895		attributes = type_attribute[access_atribute]
3896		entry = variable_name[:attributes]
3897		list = entry[,list]
3898
3899	The type attributes are:
3900		s - String (default)
3901		d - Decimal
3902		x - Hexadecimal
3903		b - Boolean ([1yYtT|0nNfF])
3904		i - IP address
3905		m - MAC address
3906
3907	The access attributes are:
3908		a - Any (default)
3909		r - Read-only
3910		o - Write-once
3911		c - Change-default
3912
3913	- CONFIG_ENV_FLAGS_LIST_DEFAULT
3914		Define this to a list (string) to define the ".flags"
3915		envirnoment variable in the default or embedded environment.
3916
3917	- CONFIG_ENV_FLAGS_LIST_STATIC
3918		Define this to a list (string) to define validation that
3919		should be done if an entry is not found in the ".flags"
3920		environment variable.  To override a setting in the static
3921		list, simply add an entry for the same variable name to the
3922		".flags" variable.
3923
3924- CONFIG_ENV_ACCESS_IGNORE_FORCE
3925	If defined, don't allow the -f switch to env set override variable
3926	access flags.
3927
3928- CONFIG_SYS_GENERIC_BOARD
3929	This selects the architecture-generic board system instead of the
3930	architecture-specific board files. It is intended to move boards
3931	to this new framework over time. Defining this will disable the
3932	arch/foo/lib/board.c file and use common/board_f.c and
3933	common/board_r.c instead. To use this option your architecture
3934	must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3935	its config.mk file). If you find problems enabling this option on
3936	your board please report the problem and send patches!
3937
3938- CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3939	This is set by OMAP boards for the max time that reset should
3940	be asserted. See doc/README.omap-reset-time for details on how
3941	the value can be calulated on a given board.
3942
3943The following definitions that deal with the placement and management
3944of environment data (variable area); in general, we support the
3945following configurations:
3946
3947- CONFIG_BUILD_ENVCRC:
3948
3949	Builds up envcrc with the target environment so that external utils
3950	may easily extract it and embed it in final U-Boot images.
3951
3952- CONFIG_ENV_IS_IN_FLASH:
3953
3954	Define this if the environment is in flash memory.
3955
3956	a) The environment occupies one whole flash sector, which is
3957	   "embedded" in the text segment with the U-Boot code. This
3958	   happens usually with "bottom boot sector" or "top boot
3959	   sector" type flash chips, which have several smaller
3960	   sectors at the start or the end. For instance, such a
3961	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3962	   such a case you would place the environment in one of the
3963	   4 kB sectors - with U-Boot code before and after it. With
3964	   "top boot sector" type flash chips, you would put the
3965	   environment in one of the last sectors, leaving a gap
3966	   between U-Boot and the environment.
3967
3968	- CONFIG_ENV_OFFSET:
3969
3970	   Offset of environment data (variable area) to the
3971	   beginning of flash memory; for instance, with bottom boot
3972	   type flash chips the second sector can be used: the offset
3973	   for this sector is given here.
3974
3975	   CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3976
3977	- CONFIG_ENV_ADDR:
3978
3979	   This is just another way to specify the start address of
3980	   the flash sector containing the environment (instead of
3981	   CONFIG_ENV_OFFSET).
3982
3983	- CONFIG_ENV_SECT_SIZE:
3984
3985	   Size of the sector containing the environment.
3986
3987
3988	b) Sometimes flash chips have few, equal sized, BIG sectors.
3989	   In such a case you don't want to spend a whole sector for
3990	   the environment.
3991
3992	- CONFIG_ENV_SIZE:
3993
3994	   If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3995	   and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3996	   of this flash sector for the environment. This saves
3997	   memory for the RAM copy of the environment.
3998
3999	   It may also save flash memory if you decide to use this
4000	   when your environment is "embedded" within U-Boot code,
4001	   since then the remainder of the flash sector could be used
4002	   for U-Boot code. It should be pointed out that this is
4003	   STRONGLY DISCOURAGED from a robustness point of view:
4004	   updating the environment in flash makes it always
4005	   necessary to erase the WHOLE sector. If something goes
4006	   wrong before the contents has been restored from a copy in
4007	   RAM, your target system will be dead.
4008
4009	- CONFIG_ENV_ADDR_REDUND
4010	  CONFIG_ENV_SIZE_REDUND
4011
4012	   These settings describe a second storage area used to hold
4013	   a redundant copy of the environment data, so that there is
4014	   a valid backup copy in case there is a power failure during
4015	   a "saveenv" operation.
4016
4017BE CAREFUL! Any changes to the flash layout, and some changes to the
4018source code will make it necessary to adapt <board>/u-boot.lds*
4019accordingly!
4020
4021
4022- CONFIG_ENV_IS_IN_NVRAM:
4023
4024	Define this if you have some non-volatile memory device
4025	(NVRAM, battery buffered SRAM) which you want to use for the
4026	environment.
4027
4028	- CONFIG_ENV_ADDR:
4029	- CONFIG_ENV_SIZE:
4030
4031	  These two #defines are used to determine the memory area you
4032	  want to use for environment. It is assumed that this memory
4033	  can just be read and written to, without any special
4034	  provision.
4035
4036BE CAREFUL! The first access to the environment happens quite early
4037in U-Boot initalization (when we try to get the setting of for the
4038console baudrate). You *MUST* have mapped your NVRAM area then, or
4039U-Boot will hang.
4040
4041Please note that even with NVRAM we still use a copy of the
4042environment in RAM: we could work on NVRAM directly, but we want to
4043keep settings there always unmodified except somebody uses "saveenv"
4044to save the current settings.
4045
4046
4047- CONFIG_ENV_IS_IN_EEPROM:
4048
4049	Use this if you have an EEPROM or similar serial access
4050	device and a driver for it.
4051
4052	- CONFIG_ENV_OFFSET:
4053	- CONFIG_ENV_SIZE:
4054
4055	  These two #defines specify the offset and size of the
4056	  environment area within the total memory of your EEPROM.
4057
4058	- CONFIG_SYS_I2C_EEPROM_ADDR:
4059	  If defined, specified the chip address of the EEPROM device.
4060	  The default address is zero.
4061
4062	- CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4063	  If defined, the number of bits used to address bytes in a
4064	  single page in the EEPROM device.  A 64 byte page, for example
4065	  would require six bits.
4066
4067	- CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4068	  If defined, the number of milliseconds to delay between
4069	  page writes.	The default is zero milliseconds.
4070
4071	- CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4072	  The length in bytes of the EEPROM memory array address.  Note
4073	  that this is NOT the chip address length!
4074
4075	- CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4076	  EEPROM chips that implement "address overflow" are ones
4077	  like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4078	  address and the extra bits end up in the "chip address" bit
4079	  slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4080	  byte chips.
4081
4082	  Note that we consider the length of the address field to
4083	  still be one byte because the extra address bits are hidden
4084	  in the chip address.
4085
4086	- CONFIG_SYS_EEPROM_SIZE:
4087	  The size in bytes of the EEPROM device.
4088
4089	- CONFIG_ENV_EEPROM_IS_ON_I2C
4090	  define this, if you have I2C and SPI activated, and your
4091	  EEPROM, which holds the environment, is on the I2C bus.
4092
4093	- CONFIG_I2C_ENV_EEPROM_BUS
4094	  if you have an Environment on an EEPROM reached over
4095	  I2C muxes, you can define here, how to reach this
4096	  EEPROM. For example:
4097
4098	  #define CONFIG_I2C_ENV_EEPROM_BUS	  1
4099
4100	  EEPROM which holds the environment, is reached over
4101	  a pca9547 i2c mux with address 0x70, channel 3.
4102
4103- CONFIG_ENV_IS_IN_DATAFLASH:
4104
4105	Define this if you have a DataFlash memory device which you
4106	want to use for the environment.
4107
4108	- CONFIG_ENV_OFFSET:
4109	- CONFIG_ENV_ADDR:
4110	- CONFIG_ENV_SIZE:
4111
4112	  These three #defines specify the offset and size of the
4113	  environment area within the total memory of your DataFlash placed
4114	  at the specified address.
4115
4116- CONFIG_ENV_IS_IN_SPI_FLASH:
4117
4118	Define this if you have a SPI Flash memory device which you
4119	want to use for the environment.
4120
4121	- CONFIG_ENV_OFFSET:
4122	- CONFIG_ENV_SIZE:
4123
4124	  These two #defines specify the offset and size of the
4125	  environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4126	  aligned to an erase sector boundary.
4127
4128	- CONFIG_ENV_SECT_SIZE:
4129
4130	  Define the SPI flash's sector size.
4131
4132	- CONFIG_ENV_OFFSET_REDUND (optional):
4133
4134	  This setting describes a second storage area of CONFIG_ENV_SIZE
4135	  size used to hold a redundant copy of the environment data, so
4136	  that there is a valid backup copy in case there is a power failure
4137	  during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4138	  aligned to an erase sector boundary.
4139
4140	- CONFIG_ENV_SPI_BUS (optional):
4141	- CONFIG_ENV_SPI_CS (optional):
4142
4143	  Define the SPI bus and chip select. If not defined they will be 0.
4144
4145	- CONFIG_ENV_SPI_MAX_HZ (optional):
4146
4147	  Define the SPI max work clock. If not defined then use 1MHz.
4148
4149	- CONFIG_ENV_SPI_MODE (optional):
4150
4151	  Define the SPI work mode. If not defined then use SPI_MODE_3.
4152
4153- CONFIG_ENV_IS_IN_REMOTE:
4154
4155	Define this if you have a remote memory space which you
4156	want to use for the local device's environment.
4157
4158	- CONFIG_ENV_ADDR:
4159	- CONFIG_ENV_SIZE:
4160
4161	  These two #defines specify the address and size of the
4162	  environment area within the remote memory space. The
4163	  local device can get the environment from remote memory
4164	  space by SRIO or PCIE links.
4165
4166BE CAREFUL! For some special cases, the local device can not use
4167"saveenv" command. For example, the local device will get the
4168environment stored in a remote NOR flash by SRIO or PCIE link,
4169but it can not erase, write this NOR flash by SRIO or PCIE interface.
4170
4171- CONFIG_ENV_IS_IN_NAND:
4172
4173	Define this if you have a NAND device which you want to use
4174	for the environment.
4175
4176	- CONFIG_ENV_OFFSET:
4177	- CONFIG_ENV_SIZE:
4178
4179	  These two #defines specify the offset and size of the environment
4180	  area within the first NAND device.  CONFIG_ENV_OFFSET must be
4181	  aligned to an erase block boundary.
4182
4183	- CONFIG_ENV_OFFSET_REDUND (optional):
4184
4185	  This setting describes a second storage area of CONFIG_ENV_SIZE
4186	  size used to hold a redundant copy of the environment data, so
4187	  that there is a valid backup copy in case there is a power failure
4188	  during a "saveenv" operation.	 CONFIG_ENV_OFFSET_RENDUND must be
4189	  aligned to an erase block boundary.
4190
4191	- CONFIG_ENV_RANGE (optional):
4192
4193	  Specifies the length of the region in which the environment
4194	  can be written.  This should be a multiple of the NAND device's
4195	  block size.  Specifying a range with more erase blocks than
4196	  are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4197	  the range to be avoided.
4198
4199	- CONFIG_ENV_OFFSET_OOB (optional):
4200
4201	  Enables support for dynamically retrieving the offset of the
4202	  environment from block zero's out-of-band data.  The
4203	  "nand env.oob" command can be used to record this offset.
4204	  Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4205	  using CONFIG_ENV_OFFSET_OOB.
4206
4207- CONFIG_NAND_ENV_DST
4208
4209	Defines address in RAM to which the nand_spl code should copy the
4210	environment. If redundant environment is used, it will be copied to
4211	CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4212
4213- CONFIG_ENV_IS_IN_UBI:
4214
4215	Define this if you have an UBI volume that you want to use for the
4216	environment.  This has the benefit of wear-leveling the environment
4217	accesses, which is important on NAND.
4218
4219	- CONFIG_ENV_UBI_PART:
4220
4221	  Define this to a string that is the mtd partition containing the UBI.
4222
4223	- CONFIG_ENV_UBI_VOLUME:
4224
4225	  Define this to the name of the volume that you want to store the
4226	  environment in.
4227
4228	- CONFIG_ENV_UBI_VOLUME_REDUND:
4229
4230	  Define this to the name of another volume to store a second copy of
4231	  the environment in.  This will enable redundant environments in UBI.
4232	  It is assumed that both volumes are in the same MTD partition.
4233
4234	- CONFIG_UBI_SILENCE_MSG
4235	- CONFIG_UBIFS_SILENCE_MSG
4236
4237	  You will probably want to define these to avoid a really noisy system
4238	  when storing the env in UBI.
4239
4240- CONFIG_ENV_IS_IN_FAT:
4241       Define this if you want to use the FAT file system for the environment.
4242
4243       - FAT_ENV_INTERFACE:
4244
4245         Define this to a string that is the name of the block device.
4246
4247       - FAT_ENV_DEV_AND_PART:
4248
4249         Define this to a string to specify the partition of the device. It can
4250         be as following:
4251
4252           "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4253               - "D:P": device D partition P. Error occurs if device D has no
4254                        partition table.
4255               - "D:0": device D.
4256               - "D" or "D:": device D partition 1 if device D has partition
4257                              table, or the whole device D if has no partition
4258                              table.
4259               - "D:auto": first partition in device D with bootable flag set.
4260                           If none, first valid paratition in device D. If no
4261                           partition table then means device D.
4262
4263       - FAT_ENV_FILE:
4264
4265         It's a string of the FAT file name. This file use to store the
4266         envrionment.
4267
4268       - CONFIG_FAT_WRITE:
4269         This should be defined. Otherwise it cannot save the envrionment file.
4270
4271- CONFIG_ENV_IS_IN_MMC:
4272
4273	Define this if you have an MMC device which you want to use for the
4274	environment.
4275
4276	- CONFIG_SYS_MMC_ENV_DEV:
4277
4278	  Specifies which MMC device the environment is stored in.
4279
4280	- CONFIG_SYS_MMC_ENV_PART (optional):
4281
4282	  Specifies which MMC partition the environment is stored in. If not
4283	  set, defaults to partition 0, the user area. Common values might be
4284	  1 (first MMC boot partition), 2 (second MMC boot partition).
4285
4286	- CONFIG_ENV_OFFSET:
4287	- CONFIG_ENV_SIZE:
4288
4289	  These two #defines specify the offset and size of the environment
4290	  area within the specified MMC device.
4291
4292	  If offset is positive (the usual case), it is treated as relative to
4293	  the start of the MMC partition. If offset is negative, it is treated
4294	  as relative to the end of the MMC partition. This can be useful if
4295	  your board may be fitted with different MMC devices, which have
4296	  different sizes for the MMC partitions, and you always want the
4297	  environment placed at the very end of the partition, to leave the
4298	  maximum possible space before it, to store other data.
4299
4300	  These two values are in units of bytes, but must be aligned to an
4301	  MMC sector boundary.
4302
4303	- CONFIG_ENV_OFFSET_REDUND (optional):
4304
4305	  Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4306	  hold a redundant copy of the environment data. This provides a
4307	  valid backup copy in case the other copy is corrupted, e.g. due
4308	  to a power failure during a "saveenv" operation.
4309
4310	  This value may also be positive or negative; this is handled in the
4311	  same way as CONFIG_ENV_OFFSET.
4312
4313	  This value is also in units of bytes, but must also be aligned to
4314	  an MMC sector boundary.
4315
4316	- CONFIG_ENV_SIZE_REDUND (optional):
4317
4318	  This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4319	  set. If this value is set, it must be set to the same value as
4320	  CONFIG_ENV_SIZE.
4321
4322- CONFIG_SYS_SPI_INIT_OFFSET
4323
4324	Defines offset to the initial SPI buffer area in DPRAM. The
4325	area is used at an early stage (ROM part) if the environment
4326	is configured to reside in the SPI EEPROM: We need a 520 byte
4327	scratch DPRAM area. It is used between the two initialization
4328	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4329	to be a good choice since it makes it far enough from the
4330	start of the data area as well as from the stack pointer.
4331
4332Please note that the environment is read-only until the monitor
4333has been relocated to RAM and a RAM copy of the environment has been
4334created; also, when using EEPROM you will have to use getenv_f()
4335until then to read environment variables.
4336
4337The environment is protected by a CRC32 checksum. Before the monitor
4338is relocated into RAM, as a result of a bad CRC you will be working
4339with the compiled-in default environment - *silently*!!! [This is
4340necessary, because the first environment variable we need is the
4341"baudrate" setting for the console - if we have a bad CRC, we don't
4342have any device yet where we could complain.]
4343
4344Note: once the monitor has been relocated, then it will complain if
4345the default environment is used; a new CRC is computed as soon as you
4346use the "saveenv" command to store a valid environment.
4347
4348- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4349		Echo the inverted Ethernet link state to the fault LED.
4350
4351		Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4352		      also needs to be defined.
4353
4354- CONFIG_SYS_FAULT_MII_ADDR:
4355		MII address of the PHY to check for the Ethernet link state.
4356
4357- CONFIG_NS16550_MIN_FUNCTIONS:
4358		Define this if you desire to only have use of the NS16550_init
4359		and NS16550_putc functions for the serial driver located at
4360		drivers/serial/ns16550.c.  This option is useful for saving
4361		space for already greatly restricted images, including but not
4362		limited to NAND_SPL configurations.
4363
4364- CONFIG_DISPLAY_BOARDINFO
4365		Display information about the board that U-Boot is running on
4366		when U-Boot starts up. The board function checkboard() is called
4367		to do this.
4368
4369- CONFIG_DISPLAY_BOARDINFO_LATE
4370		Similar to the previous option, but display this information
4371		later, once stdio is running and output goes to the LCD, if
4372		present.
4373
4374Low Level (hardware related) configuration options:
4375---------------------------------------------------
4376
4377- CONFIG_SYS_CACHELINE_SIZE:
4378		Cache Line Size of the CPU.
4379
4380- CONFIG_SYS_DEFAULT_IMMR:
4381		Default address of the IMMR after system reset.
4382
4383		Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4384		and RPXsuper) to be able to adjust the position of
4385		the IMMR register after a reset.
4386
4387- CONFIG_SYS_CCSRBAR_DEFAULT:
4388		Default (power-on reset) physical address of CCSR on Freescale
4389		PowerPC SOCs.
4390
4391- CONFIG_SYS_CCSRBAR:
4392		Virtual address of CCSR.  On a 32-bit build, this is typically
4393		the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4394
4395		CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4396		for cross-platform code that uses that macro instead.
4397
4398- CONFIG_SYS_CCSRBAR_PHYS:
4399		Physical address of CCSR.  CCSR can be relocated to a new
4400		physical address, if desired.  In this case, this macro should
4401		be set to that address.	 Otherwise, it should be set to the
4402		same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
4403		is typically relocated on 36-bit builds.  It is recommended
4404		that this macro be defined via the _HIGH and _LOW macros:
4405
4406		#define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4407			* 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4408
4409- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4410		Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS.	This value is typically
4411		either 0 (32-bit build) or 0xF (36-bit build).	This macro is
4412		used in assembly code, so it must not contain typecasts or
4413		integer size suffixes (e.g. "ULL").
4414
4415- CONFIG_SYS_CCSRBAR_PHYS_LOW:
4416		Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS.  This macro is
4417		used in assembly code, so it must not contain typecasts or
4418		integer size suffixes (e.g. "ULL").
4419
4420- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4421		If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4422		forced to a value that ensures that CCSR is not relocated.
4423
4424- Floppy Disk Support:
4425		CONFIG_SYS_FDC_DRIVE_NUMBER
4426
4427		the default drive number (default value 0)
4428
4429		CONFIG_SYS_ISA_IO_STRIDE
4430
4431		defines the spacing between FDC chipset registers
4432		(default value 1)
4433
4434		CONFIG_SYS_ISA_IO_OFFSET
4435
4436		defines the offset of register from address. It
4437		depends on which part of the data bus is connected to
4438		the FDC chipset. (default value 0)
4439
4440		If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4441		CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4442		default value.
4443
4444		if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4445		fdc_hw_init() is called at the beginning of the FDC
4446		setup. fdc_hw_init() must be provided by the board
4447		source code. It is used to make hardware dependant
4448		initializations.
4449
4450- CONFIG_IDE_AHB:
4451		Most IDE controllers were designed to be connected with PCI
4452		interface. Only few of them were designed for AHB interface.
4453		When software is doing ATA command and data transfer to
4454		IDE devices through IDE-AHB controller, some additional
4455		registers accessing to these kind of IDE-AHB controller
4456		is requierd.
4457
4458- CONFIG_SYS_IMMR:	Physical address of the Internal Memory.
4459		DO NOT CHANGE unless you know exactly what you're
4460		doing! (11-4) [MPC8xx/82xx systems only]
4461
4462- CONFIG_SYS_INIT_RAM_ADDR:
4463
4464		Start address of memory area that can be used for
4465		initial data and stack; please note that this must be
4466		writable memory that is working WITHOUT special
4467		initialization, i. e. you CANNOT use normal RAM which
4468		will become available only after programming the
4469		memory controller and running certain initialization
4470		sequences.
4471
4472		U-Boot uses the following memory types:
4473		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4474		- MPC824X: data cache
4475		- PPC4xx:  data cache
4476
4477- CONFIG_SYS_GBL_DATA_OFFSET:
4478
4479		Offset of the initial data structure in the memory
4480		area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4481		CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4482		data is located at the end of the available space
4483		(sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4484		CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4485		below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4486		CONFIG_SYS_GBL_DATA_OFFSET) downward.
4487
4488	Note:
4489		On the MPC824X (or other systems that use the data
4490		cache for initial memory) the address chosen for
4491		CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4492		point to an otherwise UNUSED address space between
4493		the top of RAM and the start of the PCI space.
4494
4495- CONFIG_SYS_SIUMCR:	SIU Module Configuration (11-6)
4496
4497- CONFIG_SYS_SYPCR:	System Protection Control (11-9)
4498
4499- CONFIG_SYS_TBSCR:	Time Base Status and Control (11-26)
4500
4501- CONFIG_SYS_PISCR:	Periodic Interrupt Status and Control (11-31)
4502
4503- CONFIG_SYS_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
4504
4505- CONFIG_SYS_SCCR:	System Clock and reset Control Register (15-27)
4506
4507- CONFIG_SYS_OR_TIMING_SDRAM:
4508		SDRAM timing
4509
4510- CONFIG_SYS_MAMR_PTA:
4511		periodic timer for refresh
4512
4513- CONFIG_SYS_DER:	Debug Event Register (37-47)
4514
4515- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4516  CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4517  CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4518  CONFIG_SYS_BR1_PRELIM:
4519		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4520
4521- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4522  CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4523  CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4524		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4525
4526- CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4527  CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4528		Machine Mode Register and Memory Periodic Timer
4529		Prescaler definitions (SDRAM timing)
4530
4531- CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4532		enable I2C microcode relocation patch (MPC8xx);
4533		define relocation offset in DPRAM [DSP2]
4534
4535- CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4536		enable SMC microcode relocation patch (MPC8xx);
4537		define relocation offset in DPRAM [SMC1]
4538
4539- CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4540		enable SPI microcode relocation patch (MPC8xx);
4541		define relocation offset in DPRAM [SCC4]
4542
4543- CONFIG_SYS_USE_OSCCLK:
4544		Use OSCM clock mode on MBX8xx board. Be careful,
4545		wrong setting might damage your board. Read
4546		doc/README.MBX before setting this variable!
4547
4548- CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4549		Offset of the bootmode word in DPRAM used by post
4550		(Power On Self Tests). This definition overrides
4551		#define'd default value in commproc.h resp.
4552		cpm_8260.h.
4553
4554- CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4555  CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4556  CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4557  CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4558  CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4559  CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4560  CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4561  CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4562		Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4563
4564- CONFIG_PCI_DISABLE_PCIE:
4565		Disable PCI-Express on systems where it is supported but not
4566		required.
4567
4568- CONFIG_PCI_ENUM_ONLY
4569		Only scan through and get the devices on the busses.
4570		Don't do any setup work, presumably because someone or
4571		something has already done it, and we don't need to do it
4572		a second time.	Useful for platforms that are pre-booted
4573		by coreboot or similar.
4574
4575- CONFIG_PCI_INDIRECT_BRIDGE:
4576		Enable support for indirect PCI bridges.
4577
4578- CONFIG_SYS_SRIO:
4579		Chip has SRIO or not
4580
4581- CONFIG_SRIO1:
4582		Board has SRIO 1 port available
4583
4584- CONFIG_SRIO2:
4585		Board has SRIO 2 port available
4586
4587- CONFIG_SRIO_PCIE_BOOT_MASTER
4588		Board can support master function for Boot from SRIO and PCIE
4589
4590- CONFIG_SYS_SRIOn_MEM_VIRT:
4591		Virtual Address of SRIO port 'n' memory region
4592
4593- CONFIG_SYS_SRIOn_MEM_PHYS:
4594		Physical Address of SRIO port 'n' memory region
4595
4596- CONFIG_SYS_SRIOn_MEM_SIZE:
4597		Size of SRIO port 'n' memory region
4598
4599- CONFIG_SYS_NAND_BUSWIDTH_16BIT
4600		Defined to tell the NAND controller that the NAND chip is using
4601		a 16 bit bus.
4602		Not all NAND drivers use this symbol.
4603		Example of drivers that use it:
4604		- drivers/mtd/nand/ndfc.c
4605		- drivers/mtd/nand/mxc_nand.c
4606
4607- CONFIG_SYS_NDFC_EBC0_CFG
4608		Sets the EBC0_CFG register for the NDFC. If not defined
4609		a default value will be used.
4610
4611- CONFIG_SPD_EEPROM
4612		Get DDR timing information from an I2C EEPROM. Common
4613		with pluggable memory modules such as SODIMMs
4614
4615  SPD_EEPROM_ADDRESS
4616		I2C address of the SPD EEPROM
4617
4618- CONFIG_SYS_SPD_BUS_NUM
4619		If SPD EEPROM is on an I2C bus other than the first
4620		one, specify here. Note that the value must resolve
4621		to something your driver can deal with.
4622
4623- CONFIG_SYS_DDR_RAW_TIMING
4624		Get DDR timing information from other than SPD. Common with
4625		soldered DDR chips onboard without SPD. DDR raw timing
4626		parameters are extracted from datasheet and hard-coded into
4627		header files or board specific files.
4628
4629- CONFIG_FSL_DDR_INTERACTIVE
4630		Enable interactive DDR debugging. See doc/README.fsl-ddr.
4631
4632- CONFIG_SYS_83XX_DDR_USES_CS0
4633		Only for 83xx systems. If specified, then DDR should
4634		be configured using CS0 and CS1 instead of CS2 and CS3.
4635
4636- CONFIG_ETHER_ON_FEC[12]
4637		Define to enable FEC[12] on a 8xx series processor.
4638
4639- CONFIG_FEC[12]_PHY
4640		Define to the hardcoded PHY address which corresponds
4641		to the given FEC; i. e.
4642			#define CONFIG_FEC1_PHY 4
4643		means that the PHY with address 4 is connected to FEC1
4644
4645		When set to -1, means to probe for first available.
4646
4647- CONFIG_FEC[12]_PHY_NORXERR
4648		The PHY does not have a RXERR line (RMII only).
4649		(so program the FEC to ignore it).
4650
4651- CONFIG_RMII
4652		Enable RMII mode for all FECs.
4653		Note that this is a global option, we can't
4654		have one FEC in standard MII mode and another in RMII mode.
4655
4656- CONFIG_CRC32_VERIFY
4657		Add a verify option to the crc32 command.
4658		The syntax is:
4659
4660		=> crc32 -v <address> <count> <crc32>
4661
4662		Where address/count indicate a memory area
4663		and crc32 is the correct crc32 which the
4664		area should have.
4665
4666- CONFIG_LOOPW
4667		Add the "loopw" memory command. This only takes effect if
4668		the memory commands are activated globally (CONFIG_CMD_MEM).
4669
4670- CONFIG_MX_CYCLIC
4671		Add the "mdc" and "mwc" memory commands. These are cyclic
4672		"md/mw" commands.
4673		Examples:
4674
4675		=> mdc.b 10 4 500
4676		This command will print 4 bytes (10,11,12,13) each 500 ms.
4677
4678		=> mwc.l 100 12345678 10
4679		This command will write 12345678 to address 100 all 10 ms.
4680
4681		This only takes effect if the memory commands are activated
4682		globally (CONFIG_CMD_MEM).
4683
4684- CONFIG_SKIP_LOWLEVEL_INIT
4685		[ARM, NDS32, MIPS only] If this variable is defined, then certain
4686		low level initializations (like setting up the memory
4687		controller) are omitted and/or U-Boot does not
4688		relocate itself into RAM.
4689
4690		Normally this variable MUST NOT be defined. The only
4691		exception is when U-Boot is loaded (to RAM) by some
4692		other boot loader or by a debugger which performs
4693		these initializations itself.
4694
4695- CONFIG_SPL_BUILD
4696		Modifies the behaviour of start.S when compiling a loader
4697		that is executed before the actual U-Boot. E.g. when
4698		compiling a NAND SPL.
4699
4700- CONFIG_TPL_BUILD
4701		Modifies the behaviour of start.S  when compiling a loader
4702		that is executed after the SPL and before the actual U-Boot.
4703		It is loaded by the SPL.
4704
4705- CONFIG_SYS_MPC85XX_NO_RESETVEC
4706		Only for 85xx systems. If this variable is specified, the section
4707		.resetvec is not kept and the section .bootpg is placed in the
4708		previous 4k of the .text section.
4709
4710- CONFIG_ARCH_MAP_SYSMEM
4711		Generally U-Boot (and in particular the md command) uses
4712		effective address. It is therefore not necessary to regard
4713		U-Boot address as virtual addresses that need to be translated
4714		to physical addresses. However, sandbox requires this, since
4715		it maintains its own little RAM buffer which contains all
4716		addressable memory. This option causes some memory accesses
4717		to be mapped through map_sysmem() / unmap_sysmem().
4718
4719- CONFIG_USE_ARCH_MEMCPY
4720  CONFIG_USE_ARCH_MEMSET
4721		If these options are used a optimized version of memcpy/memset will
4722		be used if available. These functions may be faster under some
4723		conditions but may increase the binary size.
4724
4725- CONFIG_X86_RESET_VECTOR
4726		If defined, the x86 reset vector code is included. This is not
4727		needed when U-Boot is running from Coreboot.
4728
4729- CONFIG_SYS_MPUCLK
4730		Defines the MPU clock speed (in MHz).
4731
4732		NOTE : currently only supported on AM335x platforms.
4733
4734- CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4735		Enables the RTC32K OSC on AM33xx based plattforms
4736
4737- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4738		Option to disable subpage write in NAND driver
4739		driver that uses this:
4740		drivers/mtd/nand/davinci_nand.c
4741
4742Freescale QE/FMAN Firmware Support:
4743-----------------------------------
4744
4745The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4746loading of "firmware", which is encoded in the QE firmware binary format.
4747This firmware often needs to be loaded during U-Boot booting, so macros
4748are used to identify the storage device (NOR flash, SPI, etc) and the address
4749within that device.
4750
4751- CONFIG_SYS_FMAN_FW_ADDR
4752	The address in the storage device where the FMAN microcode is located.  The
4753	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4754	is also specified.
4755
4756- CONFIG_SYS_QE_FW_ADDR
4757	The address in the storage device where the QE microcode is located.  The
4758	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4759	is also specified.
4760
4761- CONFIG_SYS_QE_FMAN_FW_LENGTH
4762	The maximum possible size of the firmware.  The firmware binary format
4763	has a field that specifies the actual size of the firmware, but it
4764	might not be possible to read any part of the firmware unless some
4765	local storage is allocated to hold the entire firmware first.
4766
4767- CONFIG_SYS_QE_FMAN_FW_IN_NOR
4768	Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4769	normal addressable memory via the LBC.  CONFIG_SYS_FMAN_FW_ADDR is the
4770	virtual address in NOR flash.
4771
4772- CONFIG_SYS_QE_FMAN_FW_IN_NAND
4773	Specifies that QE/FMAN firmware is located in NAND flash.
4774	CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4775
4776- CONFIG_SYS_QE_FMAN_FW_IN_MMC
4777	Specifies that QE/FMAN firmware is located on the primary SD/MMC
4778	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4779
4780- CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4781	Specifies that QE/FMAN firmware is located on the primary SPI
4782	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4783
4784- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4785	Specifies that QE/FMAN firmware is located in the remote (master)
4786	memory space.	CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4787	can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4788	window->master inbound window->master LAW->the ucode address in
4789	master's memory space.
4790
4791Freescale Layerscape Management Complex Firmware Support:
4792---------------------------------------------------------
4793The Freescale Layerscape Management Complex (MC) supports the loading of
4794"firmware".
4795This firmware often needs to be loaded during U-Boot booting, so macros
4796are used to identify the storage device (NOR flash, SPI, etc) and the address
4797within that device.
4798
4799- CONFIG_FSL_MC_ENET
4800	Enable the MC driver for Layerscape SoCs.
4801
4802- CONFIG_SYS_LS_MC_FW_ADDR
4803	The address in the storage device where the firmware is located.  The
4804	meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
4805	is also specified.
4806
4807- CONFIG_SYS_LS_MC_FW_LENGTH
4808	The maximum possible size of the firmware.  The firmware binary format
4809	has a field that specifies the actual size of the firmware, but it
4810	might not be possible to read any part of the firmware unless some
4811	local storage is allocated to hold the entire firmware first.
4812
4813- CONFIG_SYS_LS_MC_FW_IN_NOR
4814	Specifies that MC firmware is located in NOR flash, mapped as
4815	normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
4816	virtual address in NOR flash.
4817
4818Building the Software:
4819======================
4820
4821Building U-Boot has been tested in several native build environments
4822and in many different cross environments. Of course we cannot support
4823all possibly existing versions of cross development tools in all
4824(potentially obsolete) versions. In case of tool chain problems we
4825recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4826which is extensively used to build and test U-Boot.
4827
4828If you are not using a native environment, it is assumed that you
4829have GNU cross compiling tools available in your path. In this case,
4830you must set the environment variable CROSS_COMPILE in your shell.
4831Note that no changes to the Makefile or any other source files are
4832necessary. For example using the ELDK on a 4xx CPU, please enter:
4833
4834	$ CROSS_COMPILE=ppc_4xx-
4835	$ export CROSS_COMPILE
4836
4837Note: If you wish to generate Windows versions of the utilities in
4838      the tools directory you can use the MinGW toolchain
4839      (http://www.mingw.org).  Set your HOST tools to the MinGW
4840      toolchain and execute 'make tools'.  For example:
4841
4842       $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4843
4844      Binaries such as tools/mkimage.exe will be created which can
4845      be executed on computers running Windows.
4846
4847U-Boot is intended to be simple to build. After installing the
4848sources you must configure U-Boot for one specific board type. This
4849is done by typing:
4850
4851	make NAME_defconfig
4852
4853where "NAME_defconfig" is the name of one of the existing configu-
4854rations; see boards.cfg for supported names.
4855
4856Note: for some board special configuration names may exist; check if
4857      additional information is available from the board vendor; for
4858      instance, the TQM823L systems are available without (standard)
4859      or with LCD support. You can select such additional "features"
4860      when choosing the configuration, i. e.
4861
4862      make TQM823L_defconfig
4863	- will configure for a plain TQM823L, i. e. no LCD support
4864
4865      make TQM823L_LCD_defconfig
4866	- will configure for a TQM823L with U-Boot console on LCD
4867
4868      etc.
4869
4870
4871Finally, type "make all", and you should get some working U-Boot
4872images ready for download to / installation on your system:
4873
4874- "u-boot.bin" is a raw binary image
4875- "u-boot" is an image in ELF binary format
4876- "u-boot.srec" is in Motorola S-Record format
4877
4878By default the build is performed locally and the objects are saved
4879in the source directory. One of the two methods can be used to change
4880this behavior and build U-Boot to some external directory:
4881
48821. Add O= to the make command line invocations:
4883
4884	make O=/tmp/build distclean
4885	make O=/tmp/build NAME_defconfig
4886	make O=/tmp/build all
4887
48882. Set environment variable BUILD_DIR to point to the desired location:
4889
4890	export BUILD_DIR=/tmp/build
4891	make distclean
4892	make NAME_defconfig
4893	make all
4894
4895Note that the command line "O=" setting overrides the BUILD_DIR environment
4896variable.
4897
4898
4899Please be aware that the Makefiles assume you are using GNU make, so
4900for instance on NetBSD you might need to use "gmake" instead of
4901native "make".
4902
4903
4904If the system board that you have is not listed, then you will need
4905to port U-Boot to your hardware platform. To do this, follow these
4906steps:
4907
49081.  Add a new configuration option for your board to the toplevel
4909    "boards.cfg" file, using the existing entries as examples.
4910    Follow the instructions there to keep the boards in order.
49112.  Create a new directory to hold your board specific code. Add any
4912    files you need. In your board directory, you will need at least
4913    the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
49143.  Create a new configuration file "include/configs/<board>.h" for
4915    your board
49163.  If you're porting U-Boot to a new CPU, then also create a new
4917    directory to hold your CPU specific code. Add any files you need.
49184.  Run "make <board>_defconfig" with your new name.
49195.  Type "make", and you should get a working "u-boot.srec" file
4920    to be installed on your target system.
49216.  Debug and solve any problems that might arise.
4922    [Of course, this last step is much harder than it sounds.]
4923
4924
4925Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4926==============================================================
4927
4928If you have modified U-Boot sources (for instance added a new board
4929or support for new devices, a new CPU, etc.) you are expected to
4930provide feedback to the other developers. The feedback normally takes
4931the form of a "patch", i. e. a context diff against a certain (latest
4932official or latest in the git repository) version of U-Boot sources.
4933
4934But before you submit such a patch, please verify that your modifi-
4935cation did not break existing code. At least make sure that *ALL* of
4936the supported boards compile WITHOUT ANY compiler warnings. To do so,
4937just run the "MAKEALL" script, which will configure and build U-Boot
4938for ALL supported system. Be warned, this will take a while. You can
4939select which (cross) compiler to use by passing a `CROSS_COMPILE'
4940environment variable to the script, i. e. to use the ELDK cross tools
4941you can type
4942
4943	CROSS_COMPILE=ppc_8xx- MAKEALL
4944
4945or to build on a native PowerPC system you can type
4946
4947	CROSS_COMPILE=' ' MAKEALL
4948
4949When using the MAKEALL script, the default behaviour is to build
4950U-Boot in the source directory. This location can be changed by
4951setting the BUILD_DIR environment variable. Also, for each target
4952built, the MAKEALL script saves two log files (<target>.ERR and
4953<target>.MAKEALL) in the <source dir>/LOG directory. This default
4954location can be changed by setting the MAKEALL_LOGDIR environment
4955variable. For example:
4956
4957	export BUILD_DIR=/tmp/build
4958	export MAKEALL_LOGDIR=/tmp/log
4959	CROSS_COMPILE=ppc_8xx- MAKEALL
4960
4961With the above settings build objects are saved in the /tmp/build,
4962log files are saved in the /tmp/log and the source tree remains clean
4963during the whole build process.
4964
4965
4966See also "U-Boot Porting Guide" below.
4967
4968
4969Monitor Commands - Overview:
4970============================
4971
4972go	- start application at address 'addr'
4973run	- run commands in an environment variable
4974bootm	- boot application image from memory
4975bootp	- boot image via network using BootP/TFTP protocol
4976bootz   - boot zImage from memory
4977tftpboot- boot image via network using TFTP protocol
4978	       and env variables "ipaddr" and "serverip"
4979	       (and eventually "gatewayip")
4980tftpput - upload a file via network using TFTP protocol
4981rarpboot- boot image via network using RARP/TFTP protocol
4982diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
4983loads	- load S-Record file over serial line
4984loadb	- load binary file over serial line (kermit mode)
4985md	- memory display
4986mm	- memory modify (auto-incrementing)
4987nm	- memory modify (constant address)
4988mw	- memory write (fill)
4989cp	- memory copy
4990cmp	- memory compare
4991crc32	- checksum calculation
4992i2c	- I2C sub-system
4993sspi	- SPI utility commands
4994base	- print or set address offset
4995printenv- print environment variables
4996setenv	- set environment variables
4997saveenv - save environment variables to persistent storage
4998protect - enable or disable FLASH write protection
4999erase	- erase FLASH memory
5000flinfo	- print FLASH memory information
5001nand	- NAND memory operations (see doc/README.nand)
5002bdinfo	- print Board Info structure
5003iminfo	- print header information for application image
5004coninfo - print console devices and informations
5005ide	- IDE sub-system
5006loop	- infinite loop on address range
5007loopw	- infinite write loop on address range
5008mtest	- simple RAM test
5009icache	- enable or disable instruction cache
5010dcache	- enable or disable data cache
5011reset	- Perform RESET of the CPU
5012echo	- echo args to console
5013version - print monitor version
5014help	- print online help
5015?	- alias for 'help'
5016
5017
5018Monitor Commands - Detailed Description:
5019========================================
5020
5021TODO.
5022
5023For now: just type "help <command>".
5024
5025
5026Environment Variables:
5027======================
5028
5029U-Boot supports user configuration using Environment Variables which
5030can be made persistent by saving to Flash memory.
5031
5032Environment Variables are set using "setenv", printed using
5033"printenv", and saved to Flash using "saveenv". Using "setenv"
5034without a value can be used to delete a variable from the
5035environment. As long as you don't save the environment you are
5036working with an in-memory copy. In case the Flash area containing the
5037environment is erased by accident, a default environment is provided.
5038
5039Some configuration options can be set using Environment Variables.
5040
5041List of environment variables (most likely not complete):
5042
5043  baudrate	- see CONFIG_BAUDRATE
5044
5045  bootdelay	- see CONFIG_BOOTDELAY
5046
5047  bootcmd	- see CONFIG_BOOTCOMMAND
5048
5049  bootargs	- Boot arguments when booting an RTOS image
5050
5051  bootfile	- Name of the image to load with TFTP
5052
5053  bootm_low	- Memory range available for image processing in the bootm
5054		  command can be restricted. This variable is given as
5055		  a hexadecimal number and defines lowest address allowed
5056		  for use by the bootm command. See also "bootm_size"
5057		  environment variable. Address defined by "bootm_low" is
5058		  also the base of the initial memory mapping for the Linux
5059		  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5060		  bootm_mapsize.
5061
5062  bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5063		  This variable is given as a hexadecimal number and it
5064		  defines the size of the memory region starting at base
5065		  address bootm_low that is accessible by the Linux kernel
5066		  during early boot.  If unset, CONFIG_SYS_BOOTMAPSZ is used
5067		  as the default value if it is defined, and bootm_size is
5068		  used otherwise.
5069
5070  bootm_size	- Memory range available for image processing in the bootm
5071		  command can be restricted. This variable is given as
5072		  a hexadecimal number and defines the size of the region
5073		  allowed for use by the bootm command. See also "bootm_low"
5074		  environment variable.
5075
5076  updatefile	- Location of the software update file on a TFTP server, used
5077		  by the automatic software update feature. Please refer to
5078		  documentation in doc/README.update for more details.
5079
5080  autoload	- if set to "no" (any string beginning with 'n'),
5081		  "bootp" will just load perform a lookup of the
5082		  configuration from the BOOTP server, but not try to
5083		  load any image using TFTP
5084
5085  autostart	- if set to "yes", an image loaded using the "bootp",
5086		  "rarpboot", "tftpboot" or "diskboot" commands will
5087		  be automatically started (by internally calling
5088		  "bootm")
5089
5090		  If set to "no", a standalone image passed to the
5091		  "bootm" command will be copied to the load address
5092		  (and eventually uncompressed), but NOT be started.
5093		  This can be used to load and uncompress arbitrary
5094		  data.
5095
5096  fdt_high	- if set this restricts the maximum address that the
5097		  flattened device tree will be copied into upon boot.
5098		  For example, if you have a system with 1 GB memory
5099		  at physical address 0x10000000, while Linux kernel
5100		  only recognizes the first 704 MB as low memory, you
5101		  may need to set fdt_high as 0x3C000000 to have the
5102		  device tree blob be copied to the maximum address
5103		  of the 704 MB low memory, so that Linux kernel can
5104		  access it during the boot procedure.
5105
5106		  If this is set to the special value 0xFFFFFFFF then
5107		  the fdt will not be copied at all on boot.  For this
5108		  to work it must reside in writable memory, have
5109		  sufficient padding on the end of it for u-boot to
5110		  add the information it needs into it, and the memory
5111		  must be accessible by the kernel.
5112
5113  fdtcontroladdr- if set this is the address of the control flattened
5114		  device tree used by U-Boot when CONFIG_OF_CONTROL is
5115		  defined.
5116
5117  i2cfast	- (PPC405GP|PPC405EP only)
5118		  if set to 'y' configures Linux I2C driver for fast
5119		  mode (400kHZ). This environment variable is used in
5120		  initialization code. So, for changes to be effective
5121		  it must be saved and board must be reset.
5122
5123  initrd_high	- restrict positioning of initrd images:
5124		  If this variable is not set, initrd images will be
5125		  copied to the highest possible address in RAM; this
5126		  is usually what you want since it allows for
5127		  maximum initrd size. If for some reason you want to
5128		  make sure that the initrd image is loaded below the
5129		  CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5130		  variable to a value of "no" or "off" or "0".
5131		  Alternatively, you can set it to a maximum upper
5132		  address to use (U-Boot will still check that it
5133		  does not overwrite the U-Boot stack and data).
5134
5135		  For instance, when you have a system with 16 MB
5136		  RAM, and want to reserve 4 MB from use by Linux,
5137		  you can do this by adding "mem=12M" to the value of
5138		  the "bootargs" variable. However, now you must make
5139		  sure that the initrd image is placed in the first
5140		  12 MB as well - this can be done with
5141
5142		  setenv initrd_high 00c00000
5143
5144		  If you set initrd_high to 0xFFFFFFFF, this is an
5145		  indication to U-Boot that all addresses are legal
5146		  for the Linux kernel, including addresses in flash
5147		  memory. In this case U-Boot will NOT COPY the
5148		  ramdisk at all. This may be useful to reduce the
5149		  boot time on your system, but requires that this
5150		  feature is supported by your Linux kernel.
5151
5152  ipaddr	- IP address; needed for tftpboot command
5153
5154  loadaddr	- Default load address for commands like "bootp",
5155		  "rarpboot", "tftpboot", "loadb" or "diskboot"
5156
5157  loads_echo	- see CONFIG_LOADS_ECHO
5158
5159  serverip	- TFTP server IP address; needed for tftpboot command
5160
5161  bootretry	- see CONFIG_BOOT_RETRY_TIME
5162
5163  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
5164
5165  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
5166
5167  ethprime	- controls which interface is used first.
5168
5169  ethact	- controls which interface is currently active.
5170		  For example you can do the following
5171
5172		  => setenv ethact FEC
5173		  => ping 192.168.0.1 # traffic sent on FEC
5174		  => setenv ethact SCC
5175		  => ping 10.0.0.1 # traffic sent on SCC
5176
5177  ethrotate	- When set to "no" U-Boot does not go through all
5178		  available network interfaces.
5179		  It just stays at the currently selected interface.
5180
5181  netretry	- When set to "no" each network operation will
5182		  either succeed or fail without retrying.
5183		  When set to "once" the network operation will
5184		  fail when all the available network interfaces
5185		  are tried once without success.
5186		  Useful on scripts which control the retry operation
5187		  themselves.
5188
5189  npe_ucode	- set load address for the NPE microcode
5190
5191  silent_linux  - If set then linux will be told to boot silently, by
5192		  changing the console to be empty. If "yes" it will be
5193		  made silent. If "no" it will not be made silent. If
5194		  unset, then it will be made silent if the U-Boot console
5195		  is silent.
5196
5197  tftpsrcport	- If this is set, the value is used for TFTP's
5198		  UDP source port.
5199
5200  tftpdstport	- If this is set, the value is used for TFTP's UDP
5201		  destination port instead of the Well Know Port 69.
5202
5203  tftpblocksize - Block size to use for TFTP transfers; if not set,
5204		  we use the TFTP server's default block size
5205
5206  tftptimeout	- Retransmission timeout for TFTP packets (in milli-
5207		  seconds, minimum value is 1000 = 1 second). Defines
5208		  when a packet is considered to be lost so it has to
5209		  be retransmitted. The default is 5000 = 5 seconds.
5210		  Lowering this value may make downloads succeed
5211		  faster in networks with high packet loss rates or
5212		  with unreliable TFTP servers.
5213
5214  vlan		- When set to a value < 4095 the traffic over
5215		  Ethernet is encapsulated/received over 802.1q
5216		  VLAN tagged frames.
5217
5218The following image location variables contain the location of images
5219used in booting. The "Image" column gives the role of the image and is
5220not an environment variable name. The other columns are environment
5221variable names. "File Name" gives the name of the file on a TFTP
5222server, "RAM Address" gives the location in RAM the image will be
5223loaded to, and "Flash Location" gives the image's address in NOR
5224flash or offset in NAND flash.
5225
5226*Note* - these variables don't have to be defined for all boards, some
5227boards currenlty use other variables for these purposes, and some
5228boards use these variables for other purposes.
5229
5230Image		    File Name	     RAM Address       Flash Location
5231-----		    ---------	     -----------       --------------
5232u-boot		    u-boot	     u-boot_addr_r     u-boot_addr
5233Linux kernel	    bootfile	     kernel_addr_r     kernel_addr
5234device tree blob    fdtfile	     fdt_addr_r	       fdt_addr
5235ramdisk		    ramdiskfile	     ramdisk_addr_r    ramdisk_addr
5236
5237The following environment variables may be used and automatically
5238updated by the network boot commands ("bootp" and "rarpboot"),
5239depending the information provided by your boot server:
5240
5241  bootfile	- see above
5242  dnsip		- IP address of your Domain Name Server
5243  dnsip2	- IP address of your secondary Domain Name Server
5244  gatewayip	- IP address of the Gateway (Router) to use
5245  hostname	- Target hostname
5246  ipaddr	- see above
5247  netmask	- Subnet Mask
5248  rootpath	- Pathname of the root filesystem on the NFS server
5249  serverip	- see above
5250
5251
5252There are two special Environment Variables:
5253
5254  serial#	- contains hardware identification information such
5255		  as type string and/or serial number
5256  ethaddr	- Ethernet address
5257
5258These variables can be set only once (usually during manufacturing of
5259the board). U-Boot refuses to delete or overwrite these variables
5260once they have been set once.
5261
5262
5263Further special Environment Variables:
5264
5265  ver		- Contains the U-Boot version string as printed
5266		  with the "version" command. This variable is
5267		  readonly (see CONFIG_VERSION_VARIABLE).
5268
5269
5270Please note that changes to some configuration parameters may take
5271only effect after the next boot (yes, that's just like Windoze :-).
5272
5273
5274Callback functions for environment variables:
5275---------------------------------------------
5276
5277For some environment variables, the behavior of u-boot needs to change
5278when their values are changed.  This functionailty allows functions to
5279be associated with arbitrary variables.  On creation, overwrite, or
5280deletion, the callback will provide the opportunity for some side
5281effect to happen or for the change to be rejected.
5282
5283The callbacks are named and associated with a function using the
5284U_BOOT_ENV_CALLBACK macro in your board or driver code.
5285
5286These callbacks are associated with variables in one of two ways.  The
5287static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5288in the board configuration to a string that defines a list of
5289associations.  The list must be in the following format:
5290
5291	entry = variable_name[:callback_name]
5292	list = entry[,list]
5293
5294If the callback name is not specified, then the callback is deleted.
5295Spaces are also allowed anywhere in the list.
5296
5297Callbacks can also be associated by defining the ".callbacks" variable
5298with the same list format above.  Any association in ".callbacks" will
5299override any association in the static list. You can define
5300CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5301".callbacks" envirnoment variable in the default or embedded environment.
5302
5303
5304Command Line Parsing:
5305=====================
5306
5307There are two different command line parsers available with U-Boot:
5308the old "simple" one, and the much more powerful "hush" shell:
5309
5310Old, simple command line parser:
5311--------------------------------
5312
5313- supports environment variables (through setenv / saveenv commands)
5314- several commands on one line, separated by ';'
5315- variable substitution using "... ${name} ..." syntax
5316- special characters ('$', ';') can be escaped by prefixing with '\',
5317  for example:
5318	setenv bootcmd bootm \${address}
5319- You can also escape text by enclosing in single apostrophes, for example:
5320	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5321
5322Hush shell:
5323-----------
5324
5325- similar to Bourne shell, with control structures like
5326  if...then...else...fi, for...do...done; while...do...done,
5327  until...do...done, ...
5328- supports environment ("global") variables (through setenv / saveenv
5329  commands) and local shell variables (through standard shell syntax
5330  "name=value"); only environment variables can be used with "run"
5331  command
5332
5333General rules:
5334--------------
5335
5336(1) If a command line (or an environment variable executed by a "run"
5337    command) contains several commands separated by semicolon, and
5338    one of these commands fails, then the remaining commands will be
5339    executed anyway.
5340
5341(2) If you execute several variables with one call to run (i. e.
5342    calling run with a list of variables as arguments), any failing
5343    command will cause "run" to terminate, i. e. the remaining
5344    variables are not executed.
5345
5346Note for Redundant Ethernet Interfaces:
5347=======================================
5348
5349Some boards come with redundant Ethernet interfaces; U-Boot supports
5350such configurations and is capable of automatic selection of a
5351"working" interface when needed. MAC assignment works as follows:
5352
5353Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5354MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5355"eth1addr" (=>eth1), "eth2addr", ...
5356
5357If the network interface stores some valid MAC address (for instance
5358in SROM), this is used as default address if there is NO correspon-
5359ding setting in the environment; if the corresponding environment
5360variable is set, this overrides the settings in the card; that means:
5361
5362o If the SROM has a valid MAC address, and there is no address in the
5363  environment, the SROM's address is used.
5364
5365o If there is no valid address in the SROM, and a definition in the
5366  environment exists, then the value from the environment variable is
5367  used.
5368
5369o If both the SROM and the environment contain a MAC address, and
5370  both addresses are the same, this MAC address is used.
5371
5372o If both the SROM and the environment contain a MAC address, and the
5373  addresses differ, the value from the environment is used and a
5374  warning is printed.
5375
5376o If neither SROM nor the environment contain a MAC address, an error
5377  is raised.
5378
5379If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5380will be programmed into hardware as part of the initialization process.	 This
5381may be skipped by setting the appropriate 'ethmacskip' environment variable.
5382The naming convention is as follows:
5383"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5384
5385Image Formats:
5386==============
5387
5388U-Boot is capable of booting (and performing other auxiliary operations on)
5389images in two formats:
5390
5391New uImage format (FIT)
5392-----------------------
5393
5394Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5395to Flattened Device Tree). It allows the use of images with multiple
5396components (several kernels, ramdisks, etc.), with contents protected by
5397SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5398
5399
5400Old uImage format
5401-----------------
5402
5403Old image format is based on binary files which can be basically anything,
5404preceded by a special header; see the definitions in include/image.h for
5405details; basically, the header defines the following image properties:
5406
5407* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5408  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5409  LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5410  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5411  INTEGRITY).
5412* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5413  IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5414  Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5415* Compression Type (uncompressed, gzip, bzip2)
5416* Load Address
5417* Entry Point
5418* Image Name
5419* Image Timestamp
5420
5421The header is marked by a special Magic Number, and both the header
5422and the data portions of the image are secured against corruption by
5423CRC32 checksums.
5424
5425
5426Linux Support:
5427==============
5428
5429Although U-Boot should support any OS or standalone application
5430easily, the main focus has always been on Linux during the design of
5431U-Boot.
5432
5433U-Boot includes many features that so far have been part of some
5434special "boot loader" code within the Linux kernel. Also, any
5435"initrd" images to be used are no longer part of one big Linux image;
5436instead, kernel and "initrd" are separate images. This implementation
5437serves several purposes:
5438
5439- the same features can be used for other OS or standalone
5440  applications (for instance: using compressed images to reduce the
5441  Flash memory footprint)
5442
5443- it becomes much easier to port new Linux kernel versions because
5444  lots of low-level, hardware dependent stuff are done by U-Boot
5445
5446- the same Linux kernel image can now be used with different "initrd"
5447  images; of course this also means that different kernel images can
5448  be run with the same "initrd". This makes testing easier (you don't
5449  have to build a new "zImage.initrd" Linux image when you just
5450  change a file in your "initrd"). Also, a field-upgrade of the
5451  software is easier now.
5452
5453
5454Linux HOWTO:
5455============
5456
5457Porting Linux to U-Boot based systems:
5458---------------------------------------
5459
5460U-Boot cannot save you from doing all the necessary modifications to
5461configure the Linux device drivers for use with your target hardware
5462(no, we don't intend to provide a full virtual machine interface to
5463Linux :-).
5464
5465But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5466
5467Just make sure your machine specific header file (for instance
5468include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5469Information structure as we define in include/asm-<arch>/u-boot.h,
5470and make sure that your definition of IMAP_ADDR uses the same value
5471as your U-Boot configuration in CONFIG_SYS_IMMR.
5472
5473Note that U-Boot now has a driver model, a unified model for drivers.
5474If you are adding a new driver, plumb it into driver model. If there
5475is no uclass available, you are encouraged to create one. See
5476doc/driver-model.
5477
5478
5479Configuring the Linux kernel:
5480-----------------------------
5481
5482No specific requirements for U-Boot. Make sure you have some root
5483device (initial ramdisk, NFS) for your target system.
5484
5485
5486Building a Linux Image:
5487-----------------------
5488
5489With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5490not used. If you use recent kernel source, a new build target
5491"uImage" will exist which automatically builds an image usable by
5492U-Boot. Most older kernels also have support for a "pImage" target,
5493which was introduced for our predecessor project PPCBoot and uses a
5494100% compatible format.
5495
5496Example:
5497
5498	make TQM850L_defconfig
5499	make oldconfig
5500	make dep
5501	make uImage
5502
5503The "uImage" build target uses a special tool (in 'tools/mkimage') to
5504encapsulate a compressed Linux kernel image with header	 information,
5505CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5506
5507* build a standard "vmlinux" kernel image (in ELF binary format):
5508
5509* convert the kernel into a raw binary image:
5510
5511	${CROSS_COMPILE}-objcopy -O binary \
5512				 -R .note -R .comment \
5513				 -S vmlinux linux.bin
5514
5515* compress the binary image:
5516
5517	gzip -9 linux.bin
5518
5519* package compressed binary image for U-Boot:
5520
5521	mkimage -A ppc -O linux -T kernel -C gzip \
5522		-a 0 -e 0 -n "Linux Kernel Image" \
5523		-d linux.bin.gz uImage
5524
5525
5526The "mkimage" tool can also be used to create ramdisk images for use
5527with U-Boot, either separated from the Linux kernel image, or
5528combined into one file. "mkimage" encapsulates the images with a 64
5529byte header containing information about target architecture,
5530operating system, image type, compression method, entry points, time
5531stamp, CRC32 checksums, etc.
5532
5533"mkimage" can be called in two ways: to verify existing images and
5534print the header information, or to build new images.
5535
5536In the first form (with "-l" option) mkimage lists the information
5537contained in the header of an existing U-Boot image; this includes
5538checksum verification:
5539
5540	tools/mkimage -l image
5541	  -l ==> list image header information
5542
5543The second form (with "-d" option) is used to build a U-Boot image
5544from a "data file" which is used as image payload:
5545
5546	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5547		      -n name -d data_file image
5548	  -A ==> set architecture to 'arch'
5549	  -O ==> set operating system to 'os'
5550	  -T ==> set image type to 'type'
5551	  -C ==> set compression type 'comp'
5552	  -a ==> set load address to 'addr' (hex)
5553	  -e ==> set entry point to 'ep' (hex)
5554	  -n ==> set image name to 'name'
5555	  -d ==> use image data from 'datafile'
5556
5557Right now, all Linux kernels for PowerPC systems use the same load
5558address (0x00000000), but the entry point address depends on the
5559kernel version:
5560
5561- 2.2.x kernels have the entry point at 0x0000000C,
5562- 2.3.x and later kernels have the entry point at 0x00000000.
5563
5564So a typical call to build a U-Boot image would read:
5565
5566	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5567	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5568	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5569	> examples/uImage.TQM850L
5570	Image Name:   2.4.4 kernel for TQM850L
5571	Created:      Wed Jul 19 02:34:59 2000
5572	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5573	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5574	Load Address: 0x00000000
5575	Entry Point:  0x00000000
5576
5577To verify the contents of the image (or check for corruption):
5578
5579	-> tools/mkimage -l examples/uImage.TQM850L
5580	Image Name:   2.4.4 kernel for TQM850L
5581	Created:      Wed Jul 19 02:34:59 2000
5582	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5583	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5584	Load Address: 0x00000000
5585	Entry Point:  0x00000000
5586
5587NOTE: for embedded systems where boot time is critical you can trade
5588speed for memory and install an UNCOMPRESSED image instead: this
5589needs more space in Flash, but boots much faster since it does not
5590need to be uncompressed:
5591
5592	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5593	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5594	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5595	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5596	> examples/uImage.TQM850L-uncompressed
5597	Image Name:   2.4.4 kernel for TQM850L
5598	Created:      Wed Jul 19 02:34:59 2000
5599	Image Type:   PowerPC Linux Kernel Image (uncompressed)
5600	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
5601	Load Address: 0x00000000
5602	Entry Point:  0x00000000
5603
5604
5605Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5606when your kernel is intended to use an initial ramdisk:
5607
5608	-> tools/mkimage -n 'Simple Ramdisk Image' \
5609	> -A ppc -O linux -T ramdisk -C gzip \
5610	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5611	Image Name:   Simple Ramdisk Image
5612	Created:      Wed Jan 12 14:01:50 2000
5613	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
5614	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
5615	Load Address: 0x00000000
5616	Entry Point:  0x00000000
5617
5618The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5619option performs the converse operation of the mkimage's second form (the "-d"
5620option). Given an image built by mkimage, the dumpimage extracts a "data file"
5621from the image:
5622
5623	tools/dumpimage -i image -p position data_file
5624	  -i ==> extract from the 'image' a specific 'data_file', \
5625	   indexed by 'position'
5626
5627
5628Installing a Linux Image:
5629-------------------------
5630
5631To downloading a U-Boot image over the serial (console) interface,
5632you must convert the image to S-Record format:
5633
5634	objcopy -I binary -O srec examples/image examples/image.srec
5635
5636The 'objcopy' does not understand the information in the U-Boot
5637image header, so the resulting S-Record file will be relative to
5638address 0x00000000. To load it to a given address, you need to
5639specify the target address as 'offset' parameter with the 'loads'
5640command.
5641
5642Example: install the image to address 0x40100000 (which on the
5643TQM8xxL is in the first Flash bank):
5644
5645	=> erase 40100000 401FFFFF
5646
5647	.......... done
5648	Erased 8 sectors
5649
5650	=> loads 40100000
5651	## Ready for S-Record download ...
5652	~>examples/image.srec
5653	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5654	...
5655	15989 15990 15991 15992
5656	[file transfer complete]
5657	[connected]
5658	## Start Addr = 0x00000000
5659
5660
5661You can check the success of the download using the 'iminfo' command;
5662this includes a checksum verification so you can be sure no data
5663corruption happened:
5664
5665	=> imi 40100000
5666
5667	## Checking Image at 40100000 ...
5668	   Image Name:	 2.2.13 for initrd on TQM850L
5669	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5670	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5671	   Load Address: 00000000
5672	   Entry Point:	 0000000c
5673	   Verifying Checksum ... OK
5674
5675
5676Boot Linux:
5677-----------
5678
5679The "bootm" command is used to boot an application that is stored in
5680memory (RAM or Flash). In case of a Linux kernel image, the contents
5681of the "bootargs" environment variable is passed to the kernel as
5682parameters. You can check and modify this variable using the
5683"printenv" and "setenv" commands:
5684
5685
5686	=> printenv bootargs
5687	bootargs=root=/dev/ram
5688
5689	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5690
5691	=> printenv bootargs
5692	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5693
5694	=> bootm 40020000
5695	## Booting Linux kernel at 40020000 ...
5696	   Image Name:	 2.2.13 for NFS on TQM850L
5697	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5698	   Data Size:	 381681 Bytes = 372 kB = 0 MB
5699	   Load Address: 00000000
5700	   Entry Point:	 0000000c
5701	   Verifying Checksum ... OK
5702	   Uncompressing Kernel Image ... OK
5703	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
5704	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5705	time_init: decrementer frequency = 187500000/60
5706	Calibrating delay loop... 49.77 BogoMIPS
5707	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5708	...
5709
5710If you want to boot a Linux kernel with initial RAM disk, you pass
5711the memory addresses of both the kernel and the initrd image (PPBCOOT
5712format!) to the "bootm" command:
5713
5714	=> imi 40100000 40200000
5715
5716	## Checking Image at 40100000 ...
5717	   Image Name:	 2.2.13 for initrd on TQM850L
5718	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5719	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5720	   Load Address: 00000000
5721	   Entry Point:	 0000000c
5722	   Verifying Checksum ... OK
5723
5724	## Checking Image at 40200000 ...
5725	   Image Name:	 Simple Ramdisk Image
5726	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5727	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5728	   Load Address: 00000000
5729	   Entry Point:	 00000000
5730	   Verifying Checksum ... OK
5731
5732	=> bootm 40100000 40200000
5733	## Booting Linux kernel at 40100000 ...
5734	   Image Name:	 2.2.13 for initrd on TQM850L
5735	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5736	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5737	   Load Address: 00000000
5738	   Entry Point:	 0000000c
5739	   Verifying Checksum ... OK
5740	   Uncompressing Kernel Image ... OK
5741	## Loading RAMDisk Image at 40200000 ...
5742	   Image Name:	 Simple Ramdisk Image
5743	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5744	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5745	   Load Address: 00000000
5746	   Entry Point:	 00000000
5747	   Verifying Checksum ... OK
5748	   Loading Ramdisk ... OK
5749	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
5750	Boot arguments: root=/dev/ram
5751	time_init: decrementer frequency = 187500000/60
5752	Calibrating delay loop... 49.77 BogoMIPS
5753	...
5754	RAMDISK: Compressed image found at block 0
5755	VFS: Mounted root (ext2 filesystem).
5756
5757	bash#
5758
5759Boot Linux and pass a flat device tree:
5760-----------
5761
5762First, U-Boot must be compiled with the appropriate defines. See the section
5763titled "Linux Kernel Interface" above for a more in depth explanation. The
5764following is an example of how to start a kernel and pass an updated
5765flat device tree:
5766
5767=> print oftaddr
5768oftaddr=0x300000
5769=> print oft
5770oft=oftrees/mpc8540ads.dtb
5771=> tftp $oftaddr $oft
5772Speed: 1000, full duplex
5773Using TSEC0 device
5774TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5775Filename 'oftrees/mpc8540ads.dtb'.
5776Load address: 0x300000
5777Loading: #
5778done
5779Bytes transferred = 4106 (100a hex)
5780=> tftp $loadaddr $bootfile
5781Speed: 1000, full duplex
5782Using TSEC0 device
5783TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5784Filename 'uImage'.
5785Load address: 0x200000
5786Loading:############
5787done
5788Bytes transferred = 1029407 (fb51f hex)
5789=> print loadaddr
5790loadaddr=200000
5791=> print oftaddr
5792oftaddr=0x300000
5793=> bootm $loadaddr - $oftaddr
5794## Booting image at 00200000 ...
5795   Image Name:	 Linux-2.6.17-dirty
5796   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5797   Data Size:	 1029343 Bytes = 1005.2 kB
5798   Load Address: 00000000
5799   Entry Point:	 00000000
5800   Verifying Checksum ... OK
5801   Uncompressing Kernel Image ... OK
5802Booting using flat device tree at 0x300000
5803Using MPC85xx ADS machine description
5804Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5805[snip]
5806
5807
5808More About U-Boot Image Types:
5809------------------------------
5810
5811U-Boot supports the following image types:
5812
5813   "Standalone Programs" are directly runnable in the environment
5814	provided by U-Boot; it is expected that (if they behave
5815	well) you can continue to work in U-Boot after return from
5816	the Standalone Program.
5817   "OS Kernel Images" are usually images of some Embedded OS which
5818	will take over control completely. Usually these programs
5819	will install their own set of exception handlers, device
5820	drivers, set up the MMU, etc. - this means, that you cannot
5821	expect to re-enter U-Boot except by resetting the CPU.
5822   "RAMDisk Images" are more or less just data blocks, and their
5823	parameters (address, size) are passed to an OS kernel that is
5824	being started.
5825   "Multi-File Images" contain several images, typically an OS
5826	(Linux) kernel image and one or more data images like
5827	RAMDisks. This construct is useful for instance when you want
5828	to boot over the network using BOOTP etc., where the boot
5829	server provides just a single image file, but you want to get
5830	for instance an OS kernel and a RAMDisk image.
5831
5832	"Multi-File Images" start with a list of image sizes, each
5833	image size (in bytes) specified by an "uint32_t" in network
5834	byte order. This list is terminated by an "(uint32_t)0".
5835	Immediately after the terminating 0 follow the images, one by
5836	one, all aligned on "uint32_t" boundaries (size rounded up to
5837	a multiple of 4 bytes).
5838
5839   "Firmware Images" are binary images containing firmware (like
5840	U-Boot or FPGA images) which usually will be programmed to
5841	flash memory.
5842
5843   "Script files" are command sequences that will be executed by
5844	U-Boot's command interpreter; this feature is especially
5845	useful when you configure U-Boot to use a real shell (hush)
5846	as command interpreter.
5847
5848Booting the Linux zImage:
5849-------------------------
5850
5851On some platforms, it's possible to boot Linux zImage. This is done
5852using the "bootz" command. The syntax of "bootz" command is the same
5853as the syntax of "bootm" command.
5854
5855Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5856kernel with raw initrd images. The syntax is slightly different, the
5857address of the initrd must be augmented by it's size, in the following
5858format: "<initrd addres>:<initrd size>".
5859
5860
5861Standalone HOWTO:
5862=================
5863
5864One of the features of U-Boot is that you can dynamically load and
5865run "standalone" applications, which can use some resources of
5866U-Boot like console I/O functions or interrupt services.
5867
5868Two simple examples are included with the sources:
5869
5870"Hello World" Demo:
5871-------------------
5872
5873'examples/hello_world.c' contains a small "Hello World" Demo
5874application; it is automatically compiled when you build U-Boot.
5875It's configured to run at address 0x00040004, so you can play with it
5876like that:
5877
5878	=> loads
5879	## Ready for S-Record download ...
5880	~>examples/hello_world.srec
5881	1 2 3 4 5 6 7 8 9 10 11 ...
5882	[file transfer complete]
5883	[connected]
5884	## Start Addr = 0x00040004
5885
5886	=> go 40004 Hello World! This is a test.
5887	## Starting application at 0x00040004 ...
5888	Hello World
5889	argc = 7
5890	argv[0] = "40004"
5891	argv[1] = "Hello"
5892	argv[2] = "World!"
5893	argv[3] = "This"
5894	argv[4] = "is"
5895	argv[5] = "a"
5896	argv[6] = "test."
5897	argv[7] = "<NULL>"
5898	Hit any key to exit ...
5899
5900	## Application terminated, rc = 0x0
5901
5902Another example, which demonstrates how to register a CPM interrupt
5903handler with the U-Boot code, can be found in 'examples/timer.c'.
5904Here, a CPM timer is set up to generate an interrupt every second.
5905The interrupt service routine is trivial, just printing a '.'
5906character, but this is just a demo program. The application can be
5907controlled by the following keys:
5908
5909	? - print current values og the CPM Timer registers
5910	b - enable interrupts and start timer
5911	e - stop timer and disable interrupts
5912	q - quit application
5913
5914	=> loads
5915	## Ready for S-Record download ...
5916	~>examples/timer.srec
5917	1 2 3 4 5 6 7 8 9 10 11 ...
5918	[file transfer complete]
5919	[connected]
5920	## Start Addr = 0x00040004
5921
5922	=> go 40004
5923	## Starting application at 0x00040004 ...
5924	TIMERS=0xfff00980
5925	Using timer 1
5926	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5927
5928Hit 'b':
5929	[q, b, e, ?] Set interval 1000000 us
5930	Enabling timer
5931Hit '?':
5932	[q, b, e, ?] ........
5933	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5934Hit '?':
5935	[q, b, e, ?] .
5936	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5937Hit '?':
5938	[q, b, e, ?] .
5939	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5940Hit '?':
5941	[q, b, e, ?] .
5942	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5943Hit 'e':
5944	[q, b, e, ?] ...Stopping timer
5945Hit 'q':
5946	[q, b, e, ?] ## Application terminated, rc = 0x0
5947
5948
5949Minicom warning:
5950================
5951
5952Over time, many people have reported problems when trying to use the
5953"minicom" terminal emulation program for serial download. I (wd)
5954consider minicom to be broken, and recommend not to use it. Under
5955Unix, I recommend to use C-Kermit for general purpose use (and
5956especially for kermit binary protocol download ("loadb" command), and
5957use "cu" for S-Record download ("loads" command).  See
5958http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5959for help with kermit.
5960
5961
5962Nevertheless, if you absolutely want to use it try adding this
5963configuration to your "File transfer protocols" section:
5964
5965	   Name	   Program			Name U/D FullScr IO-Red. Multi
5966	X  kermit  /usr/bin/kermit -i -l %l -s	 Y    U	   Y	   N	  N
5967	Y  kermit  /usr/bin/kermit -i -l %l -r	 N    D	   Y	   N	  N
5968
5969
5970NetBSD Notes:
5971=============
5972
5973Starting at version 0.9.2, U-Boot supports NetBSD both as host
5974(build U-Boot) and target system (boots NetBSD/mpc8xx).
5975
5976Building requires a cross environment; it is known to work on
5977NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5978need gmake since the Makefiles are not compatible with BSD make).
5979Note that the cross-powerpc package does not install include files;
5980attempting to build U-Boot will fail because <machine/ansi.h> is
5981missing.  This file has to be installed and patched manually:
5982
5983	# cd /usr/pkg/cross/powerpc-netbsd/include
5984	# mkdir powerpc
5985	# ln -s powerpc machine
5986	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5987	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
5988
5989Native builds *don't* work due to incompatibilities between native
5990and U-Boot include files.
5991
5992Booting assumes that (the first part of) the image booted is a
5993stage-2 loader which in turn loads and then invokes the kernel
5994proper. Loader sources will eventually appear in the NetBSD source
5995tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5996meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5997
5998
5999Implementation Internals:
6000=========================
6001
6002The following is not intended to be a complete description of every
6003implementation detail. However, it should help to understand the
6004inner workings of U-Boot and make it easier to port it to custom
6005hardware.
6006
6007
6008Initial Stack, Global Data:
6009---------------------------
6010
6011The implementation of U-Boot is complicated by the fact that U-Boot
6012starts running out of ROM (flash memory), usually without access to
6013system RAM (because the memory controller is not initialized yet).
6014This means that we don't have writable Data or BSS segments, and BSS
6015is not initialized as zero. To be able to get a C environment working
6016at all, we have to allocate at least a minimal stack. Implementation
6017options for this are defined and restricted by the CPU used: Some CPU
6018models provide on-chip memory (like the IMMR area on MPC8xx and
6019MPC826x processors), on others (parts of) the data cache can be
6020locked as (mis-) used as memory, etc.
6021
6022	Chris Hallinan posted a good summary of these issues to the
6023	U-Boot mailing list:
6024
6025	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6026	From: "Chris Hallinan" <clh@net1plus.com>
6027	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6028	...
6029
6030	Correct me if I'm wrong, folks, but the way I understand it
6031	is this: Using DCACHE as initial RAM for Stack, etc, does not
6032	require any physical RAM backing up the cache. The cleverness
6033	is that the cache is being used as a temporary supply of
6034	necessary storage before the SDRAM controller is setup. It's
6035	beyond the scope of this list to explain the details, but you
6036	can see how this works by studying the cache architecture and
6037	operation in the architecture and processor-specific manuals.
6038
6039	OCM is On Chip Memory, which I believe the 405GP has 4K. It
6040	is another option for the system designer to use as an
6041	initial stack/RAM area prior to SDRAM being available. Either
6042	option should work for you. Using CS 4 should be fine if your
6043	board designers haven't used it for something that would
6044	cause you grief during the initial boot! It is frequently not
6045	used.
6046
6047	CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6048	with your processor/board/system design. The default value
6049	you will find in any recent u-boot distribution in
6050	walnut.h should work for you. I'd set it to a value larger
6051	than your SDRAM module. If you have a 64MB SDRAM module, set
6052	it above 400_0000. Just make sure your board has no resources
6053	that are supposed to respond to that address! That code in
6054	start.S has been around a while and should work as is when
6055	you get the config right.
6056
6057	-Chris Hallinan
6058	DS4.COM, Inc.
6059
6060It is essential to remember this, since it has some impact on the C
6061code for the initialization procedures:
6062
6063* Initialized global data (data segment) is read-only. Do not attempt
6064  to write it.
6065
6066* Do not use any uninitialized global data (or implicitely initialized
6067  as zero data - BSS segment) at all - this is undefined, initiali-
6068  zation is performed later (when relocating to RAM).
6069
6070* Stack space is very limited. Avoid big data buffers or things like
6071  that.
6072
6073Having only the stack as writable memory limits means we cannot use
6074normal global data to share information beween the code. But it
6075turned out that the implementation of U-Boot can be greatly
6076simplified by making a global data structure (gd_t) available to all
6077functions. We could pass a pointer to this data as argument to _all_
6078functions, but this would bloat the code. Instead we use a feature of
6079the GCC compiler (Global Register Variables) to share the data: we
6080place a pointer (gd) to the global data into a register which we
6081reserve for this purpose.
6082
6083When choosing a register for such a purpose we are restricted by the
6084relevant  (E)ABI  specifications for the current architecture, and by
6085GCC's implementation.
6086
6087For PowerPC, the following registers have specific use:
6088	R1:	stack pointer
6089	R2:	reserved for system use
6090	R3-R4:	parameter passing and return values
6091	R5-R10: parameter passing
6092	R13:	small data area pointer
6093	R30:	GOT pointer
6094	R31:	frame pointer
6095
6096	(U-Boot also uses R12 as internal GOT pointer. r12
6097	is a volatile register so r12 needs to be reset when
6098	going back and forth between asm and C)
6099
6100    ==> U-Boot will use R2 to hold a pointer to the global data
6101
6102    Note: on PPC, we could use a static initializer (since the
6103    address of the global data structure is known at compile time),
6104    but it turned out that reserving a register results in somewhat
6105    smaller code - although the code savings are not that big (on
6106    average for all boards 752 bytes for the whole U-Boot image,
6107    624 text + 127 data).
6108
6109On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6110	http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6111
6112    ==> U-Boot will use P3 to hold a pointer to the global data
6113
6114On ARM, the following registers are used:
6115
6116	R0:	function argument word/integer result
6117	R1-R3:	function argument word
6118	R9:	platform specific
6119	R10:	stack limit (used only if stack checking is enabled)
6120	R11:	argument (frame) pointer
6121	R12:	temporary workspace
6122	R13:	stack pointer
6123	R14:	link register
6124	R15:	program counter
6125
6126    ==> U-Boot will use R9 to hold a pointer to the global data
6127
6128    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6129
6130On Nios II, the ABI is documented here:
6131	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6132
6133    ==> U-Boot will use gp to hold a pointer to the global data
6134
6135    Note: on Nios II, we give "-G0" option to gcc and don't use gp
6136    to access small data sections, so gp is free.
6137
6138On NDS32, the following registers are used:
6139
6140	R0-R1:	argument/return
6141	R2-R5:	argument
6142	R15:	temporary register for assembler
6143	R16:	trampoline register
6144	R28:	frame pointer (FP)
6145	R29:	global pointer (GP)
6146	R30:	link register (LP)
6147	R31:	stack pointer (SP)
6148	PC:	program counter (PC)
6149
6150    ==> U-Boot will use R10 to hold a pointer to the global data
6151
6152NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6153or current versions of GCC may "optimize" the code too much.
6154
6155Memory Management:
6156------------------
6157
6158U-Boot runs in system state and uses physical addresses, i.e. the
6159MMU is not used either for address mapping nor for memory protection.
6160
6161The available memory is mapped to fixed addresses using the memory
6162controller. In this process, a contiguous block is formed for each
6163memory type (Flash, SDRAM, SRAM), even when it consists of several
6164physical memory banks.
6165
6166U-Boot is installed in the first 128 kB of the first Flash bank (on
6167TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6168booting and sizing and initializing DRAM, the code relocates itself
6169to the upper end of DRAM. Immediately below the U-Boot code some
6170memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6171configuration setting]. Below that, a structure with global Board
6172Info data is placed, followed by the stack (growing downward).
6173
6174Additionally, some exception handler code is copied to the low 8 kB
6175of DRAM (0x00000000 ... 0x00001FFF).
6176
6177So a typical memory configuration with 16 MB of DRAM could look like
6178this:
6179
6180	0x0000 0000	Exception Vector code
6181	      :
6182	0x0000 1FFF
6183	0x0000 2000	Free for Application Use
6184	      :
6185	      :
6186
6187	      :
6188	      :
6189	0x00FB FF20	Monitor Stack (Growing downward)
6190	0x00FB FFAC	Board Info Data and permanent copy of global data
6191	0x00FC 0000	Malloc Arena
6192	      :
6193	0x00FD FFFF
6194	0x00FE 0000	RAM Copy of Monitor Code
6195	...		eventually: LCD or video framebuffer
6196	...		eventually: pRAM (Protected RAM - unchanged by reset)
6197	0x00FF FFFF	[End of RAM]
6198
6199
6200System Initialization:
6201----------------------
6202
6203In the reset configuration, U-Boot starts at the reset entry point
6204(on most PowerPC systems at address 0x00000100). Because of the reset
6205configuration for CS0# this is a mirror of the onboard Flash memory.
6206To be able to re-map memory U-Boot then jumps to its link address.
6207To be able to implement the initialization code in C, a (small!)
6208initial stack is set up in the internal Dual Ported RAM (in case CPUs
6209which provide such a feature like MPC8xx or MPC8260), or in a locked
6210part of the data cache. After that, U-Boot initializes the CPU core,
6211the caches and the SIU.
6212
6213Next, all (potentially) available memory banks are mapped using a
6214preliminary mapping. For example, we put them on 512 MB boundaries
6215(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6216on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6217programmed for SDRAM access. Using the temporary configuration, a
6218simple memory test is run that determines the size of the SDRAM
6219banks.
6220
6221When there is more than one SDRAM bank, and the banks are of
6222different size, the largest is mapped first. For equal size, the first
6223bank (CS2#) is mapped first. The first mapping is always for address
62240x00000000, with any additional banks following immediately to create
6225contiguous memory starting from 0.
6226
6227Then, the monitor installs itself at the upper end of the SDRAM area
6228and allocates memory for use by malloc() and for the global Board
6229Info data; also, the exception vector code is copied to the low RAM
6230pages, and the final stack is set up.
6231
6232Only after this relocation will you have a "normal" C environment;
6233until that you are restricted in several ways, mostly because you are
6234running from ROM, and because the code will have to be relocated to a
6235new address in RAM.
6236
6237
6238U-Boot Porting Guide:
6239----------------------
6240
6241[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6242list, October 2002]
6243
6244
6245int main(int argc, char *argv[])
6246{
6247	sighandler_t no_more_time;
6248
6249	signal(SIGALRM, no_more_time);
6250	alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6251
6252	if (available_money > available_manpower) {
6253		Pay consultant to port U-Boot;
6254		return 0;
6255	}
6256
6257	Download latest U-Boot source;
6258
6259	Subscribe to u-boot mailing list;
6260
6261	if (clueless)
6262		email("Hi, I am new to U-Boot, how do I get started?");
6263
6264	while (learning) {
6265		Read the README file in the top level directory;
6266		Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6267		Read applicable doc/*.README;
6268		Read the source, Luke;
6269		/* find . -name "*.[chS]" | xargs grep -i <keyword> */
6270	}
6271
6272	if (available_money > toLocalCurrency ($2500))
6273		Buy a BDI3000;
6274	else
6275		Add a lot of aggravation and time;
6276
6277	if (a similar board exists) {	/* hopefully... */
6278		cp -a board/<similar> board/<myboard>
6279		cp include/configs/<similar>.h include/configs/<myboard>.h
6280	} else {
6281		Create your own board support subdirectory;
6282		Create your own board include/configs/<myboard>.h file;
6283	}
6284	Edit new board/<myboard> files
6285	Edit new include/configs/<myboard>.h
6286
6287	while (!accepted) {
6288		while (!running) {
6289			do {
6290				Add / modify source code;
6291			} until (compiles);
6292			Debug;
6293			if (clueless)
6294				email("Hi, I am having problems...");
6295		}
6296		Send patch file to the U-Boot email list;
6297		if (reasonable critiques)
6298			Incorporate improvements from email list code review;
6299		else
6300			Defend code as written;
6301	}
6302
6303	return 0;
6304}
6305
6306void no_more_time (int sig)
6307{
6308      hire_a_guru();
6309}
6310
6311
6312Coding Standards:
6313-----------------
6314
6315All contributions to U-Boot should conform to the Linux kernel
6316coding style; see the file "Documentation/CodingStyle" and the script
6317"scripts/Lindent" in your Linux kernel source directory.
6318
6319Source files originating from a different project (for example the
6320MTD subsystem) are generally exempt from these guidelines and are not
6321reformated to ease subsequent migration to newer versions of those
6322sources.
6323
6324Please note that U-Boot is implemented in C (and to some small parts in
6325Assembler); no C++ is used, so please do not use C++ style comments (//)
6326in your code.
6327
6328Please also stick to the following formatting rules:
6329- remove any trailing white space
6330- use TAB characters for indentation and vertical alignment, not spaces
6331- make sure NOT to use DOS '\r\n' line feeds
6332- do not add more than 2 consecutive empty lines to source files
6333- do not add trailing empty lines to source files
6334
6335Submissions which do not conform to the standards may be returned
6336with a request to reformat the changes.
6337
6338
6339Submitting Patches:
6340-------------------
6341
6342Since the number of patches for U-Boot is growing, we need to
6343establish some rules. Submissions which do not conform to these rules
6344may be rejected, even when they contain important and valuable stuff.
6345
6346Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6347
6348Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6349see http://lists.denx.de/mailman/listinfo/u-boot
6350
6351When you send a patch, please include the following information with
6352it:
6353
6354* For bug fixes: a description of the bug and how your patch fixes
6355  this bug. Please try to include a way of demonstrating that the
6356  patch actually fixes something.
6357
6358* For new features: a description of the feature and your
6359  implementation.
6360
6361* A CHANGELOG entry as plaintext (separate from the patch)
6362
6363* For major contributions, your entry to the CREDITS file
6364
6365* When you add support for a new board, don't forget to add a
6366  maintainer e-mail address to the boards.cfg file, too.
6367
6368* If your patch adds new configuration options, don't forget to
6369  document these in the README file.
6370
6371* The patch itself. If you are using git (which is *strongly*
6372  recommended) you can easily generate the patch using the
6373  "git format-patch". If you then use "git send-email" to send it to
6374  the U-Boot mailing list, you will avoid most of the common problems
6375  with some other mail clients.
6376
6377  If you cannot use git, use "diff -purN OLD NEW". If your version of
6378  diff does not support these options, then get the latest version of
6379  GNU diff.
6380
6381  The current directory when running this command shall be the parent
6382  directory of the U-Boot source tree (i. e. please make sure that
6383  your patch includes sufficient directory information for the
6384  affected files).
6385
6386  We prefer patches as plain text. MIME attachments are discouraged,
6387  and compressed attachments must not be used.
6388
6389* If one logical set of modifications affects or creates several
6390  files, all these changes shall be submitted in a SINGLE patch file.
6391
6392* Changesets that contain different, unrelated modifications shall be
6393  submitted as SEPARATE patches, one patch per changeset.
6394
6395
6396Notes:
6397
6398* Before sending the patch, run the MAKEALL script on your patched
6399  source tree and make sure that no errors or warnings are reported
6400  for any of the boards.
6401
6402* Keep your modifications to the necessary minimum: A patch
6403  containing several unrelated changes or arbitrary reformats will be
6404  returned with a request to re-formatting / split it.
6405
6406* If you modify existing code, make sure that your new code does not
6407  add to the memory footprint of the code ;-) Small is beautiful!
6408  When adding new features, these should compile conditionally only
6409  (using #ifdef), and the resulting code with the new feature
6410  disabled must not need more memory than the old code without your
6411  modification.
6412
6413* Remember that there is a size limit of 100 kB per message on the
6414  u-boot mailing list. Bigger patches will be moderated. If they are
6415  reasonable and not too big, they will be acknowledged. But patches
6416  bigger than the size limit should be avoided.
6417