xref: /rk3399_rockchip-uboot/README (revision fac9640895c3f778c3d2a33521dfd95bd5cba653)
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  /arm			Files generic to ARM architecture
136    /cpu		CPU specific files
137      /arm720t		Files specific to ARM 720 CPUs
138      /arm920t		Files specific to ARM 920 CPUs
139	/at91		Files specific to Atmel AT91RM9200 CPU
140	/imx		Files specific to Freescale MC9328 i.MX CPUs
141	/s3c24x0	Files specific to Samsung S3C24X0 CPUs
142      /arm926ejs	Files specific to ARM 926 CPUs
143      /arm1136		Files specific to ARM 1136 CPUs
144      /ixp		Files specific to Intel XScale IXP CPUs
145      /pxa		Files specific to Intel XScale PXA CPUs
146      /sa1100		Files specific to Intel StrongARM SA1100 CPUs
147    /lib		Architecture specific library files
148  /avr32		Files generic to AVR32 architecture
149    /cpu		CPU specific files
150    /lib		Architecture specific library files
151  /blackfin		Files generic to Analog Devices Blackfin architecture
152    /cpu		CPU specific files
153    /lib		Architecture specific library files
154  /m68k			Files generic to m68k architecture
155    /cpu		CPU specific files
156      /mcf52x2		Files specific to Freescale ColdFire MCF52x2 CPUs
157      /mcf5227x		Files specific to Freescale ColdFire MCF5227x CPUs
158      /mcf532x		Files specific to Freescale ColdFire MCF5329 CPUs
159      /mcf5445x		Files specific to Freescale ColdFire MCF5445x CPUs
160      /mcf547x_8x	Files specific to Freescale ColdFire MCF547x_8x CPUs
161    /lib		Architecture specific library files
162  /microblaze		Files generic to microblaze architecture
163    /cpu		CPU specific files
164    /lib		Architecture specific library files
165  /mips			Files generic to MIPS architecture
166    /cpu		CPU specific files
167      /mips32		Files specific to MIPS32 CPUs
168      /xburst		Files specific to Ingenic XBurst CPUs
169    /lib		Architecture specific library files
170  /nds32		Files generic to NDS32 architecture
171    /cpu		CPU specific files
172      /n1213		Files specific to Andes Technology N1213 CPUs
173    /lib		Architecture specific library files
174  /nios2		Files generic to Altera NIOS2 architecture
175    /cpu		CPU specific files
176    /lib		Architecture specific library files
177  /openrisc		Files generic to OpenRISC architecture
178    /cpu		CPU specific files
179    /lib		Architecture specific library files
180  /powerpc		Files generic to PowerPC architecture
181    /cpu		CPU specific files
182      /74xx_7xx		Files specific to Freescale MPC74xx and 7xx CPUs
183      /mpc5xx		Files specific to Freescale MPC5xx CPUs
184      /mpc5xxx		Files specific to Freescale MPC5xxx CPUs
185      /mpc8xx		Files specific to Freescale MPC8xx CPUs
186      /mpc824x		Files specific to Freescale MPC824x CPUs
187      /mpc8260		Files specific to Freescale MPC8260 CPUs
188      /mpc85xx		Files specific to Freescale MPC85xx CPUs
189      /ppc4xx		Files specific to AMCC PowerPC 4xx CPUs
190    /lib		Architecture specific library files
191  /sh			Files generic to SH architecture
192    /cpu		CPU specific files
193      /sh2		Files specific to sh2 CPUs
194      /sh3		Files specific to sh3 CPUs
195      /sh4		Files specific to sh4 CPUs
196    /lib		Architecture specific library files
197  /sparc		Files generic to SPARC architecture
198    /cpu		CPU specific files
199      /leon2		Files specific to Gaisler LEON2 SPARC CPU
200      /leon3		Files specific to Gaisler LEON3 SPARC CPU
201    /lib		Architecture specific library files
202  /x86			Files generic to x86 architecture
203    /cpu		CPU specific files
204    /lib		Architecture specific library files
205/api			Machine/arch independent API for external apps
206/board			Board dependent files
207/common			Misc architecture independent functions
208/disk			Code for disk drive partition handling
209/doc			Documentation (don't expect too much)
210/drivers		Commonly used device drivers
211/dts			Contains Makefile for building internal U-Boot fdt.
212/examples		Example code for standalone applications, etc.
213/fs			Filesystem code (cramfs, ext2, jffs2, etc.)
214/include		Header Files
215/lib			Files generic to all architectures
216  /libfdt		Library files to support flattened device trees
217  /lzma			Library files to support LZMA decompression
218  /lzo			Library files to support LZO decompression
219/net			Networking code
220/post			Power On Self Test
221/spl			Secondary Program Loader framework
222/tools			Tools to build S-Record or U-Boot images, etc.
223
224Software Configuration:
225=======================
226
227Configuration is usually done using C preprocessor defines; the
228rationale behind that is to avoid dead code whenever possible.
229
230There are two classes of configuration variables:
231
232* Configuration _OPTIONS_:
233  These are selectable by the user and have names beginning with
234  "CONFIG_".
235
236* Configuration _SETTINGS_:
237  These depend on the hardware etc. and should not be meddled with if
238  you don't know what you're doing; they have names beginning with
239  "CONFIG_SYS_".
240
241Later we will add a configuration tool - probably similar to or even
242identical to what's used for the Linux kernel. Right now, we have to
243do the configuration by hand, which means creating some symbolic
244links and editing some configuration files. We use the TQM8xxL boards
245as an example here.
246
247
248Selection of Processor Architecture and Board Type:
249---------------------------------------------------
250
251For all supported boards there are ready-to-use default
252configurations available; just type "make <board_name>_config".
253
254Example: For a TQM823L module type:
255
256	cd u-boot
257	make TQM823L_config
258
259For the Cogent platform, you need to specify the CPU type as well;
260e.g. "make cogent_mpc8xx_config". And also configure the cogent
261directory according to the instructions in cogent/README.
262
263
264Configuration Options:
265----------------------
266
267Configuration depends on the combination of board and CPU type; all
268such information is kept in a configuration file
269"include/configs/<board_name>.h".
270
271Example: For a TQM823L module, all configuration settings are in
272"include/configs/TQM823L.h".
273
274
275Many of the options are named exactly as the corresponding Linux
276kernel configuration options. The intention is to make it easier to
277build a config tool - later.
278
279
280The following options need to be configured:
281
282- CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.
283
284- Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.
285
286- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
287		Define exactly one, e.g. CONFIG_ATSTK1002
288
289- CPU Module Type: (if CONFIG_COGENT is defined)
290		Define exactly one of
291		CONFIG_CMA286_60_OLD
292--- FIXME --- not tested yet:
293		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
294		CONFIG_CMA287_23, CONFIG_CMA287_50
295
296- Motherboard Type: (if CONFIG_COGENT is defined)
297		Define exactly one of
298		CONFIG_CMA101, CONFIG_CMA102
299
300- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
301		Define one or more of
302		CONFIG_CMA302
303
304- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
305		Define one or more of
306		CONFIG_LCD_HEARTBEAT	- update a character position on
307					  the LCD display every second with
308					  a "rotator" |\-/|\-/
309
310- Board flavour: (if CONFIG_MPC8260ADS is defined)
311		CONFIG_ADSTYPE
312		Possible values are:
313			CONFIG_SYS_8260ADS	- original MPC8260ADS
314			CONFIG_SYS_8266ADS	- MPC8266ADS
315			CONFIG_SYS_PQ2FADS	- PQ2FADS-ZU or PQ2FADS-VR
316			CONFIG_SYS_8272ADS	- MPC8272ADS
317
318- Marvell Family Member
319		CONFIG_SYS_MVFS		- define it if you want to enable
320					  multiple fs option at one time
321					  for marvell soc family
322
323- MPC824X Family Member (if CONFIG_MPC824X is defined)
324		Define exactly one of
325		CONFIG_MPC8240, CONFIG_MPC8245
326
327- 8xx CPU Options: (if using an MPC8xx CPU)
328		CONFIG_8xx_GCLK_FREQ	- deprecated: CPU clock if
329					  get_gclk_freq() cannot work
330					  e.g. if there is no 32KHz
331					  reference PIT/RTC clock
332		CONFIG_8xx_OSCLK	- PLL input clock (either EXTCLK
333					  or XTAL/EXTAL)
334
335- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
336		CONFIG_SYS_8xx_CPUCLK_MIN
337		CONFIG_SYS_8xx_CPUCLK_MAX
338		CONFIG_8xx_CPUCLK_DEFAULT
339			See doc/README.MPC866
340
341		CONFIG_SYS_MEASURE_CPUCLK
342
343		Define this to measure the actual CPU clock instead
344		of relying on the correctness of the configured
345		values. Mostly useful for board bringup to make sure
346		the PLL is locked at the intended frequency. Note
347		that this requires a (stable) reference clock (32 kHz
348		RTC clock or CONFIG_SYS_8XX_XIN)
349
350		CONFIG_SYS_DELAYED_ICACHE
351
352		Define this option if you want to enable the
353		ICache only when Code runs from RAM.
354
355- 85xx CPU Options:
356		CONFIG_SYS_PPC64
357
358		Specifies that the core is a 64-bit PowerPC implementation (implements
359		the "64" category of the Power ISA). This is necessary for ePAPR
360		compliance, among other possible reasons.
361
362		CONFIG_SYS_FSL_TBCLK_DIV
363
364		Defines the core time base clock divider ratio compared to the
365		system clock.  On most PQ3 devices this is 8, on newer QorIQ
366		devices it can be 16 or 32.  The ratio varies from SoC to Soc.
367
368		CONFIG_SYS_FSL_PCIE_COMPAT
369
370		Defines the string to utilize when trying to match PCIe device
371		tree nodes for the given platform.
372
373		CONFIG_SYS_PPC_E500_DEBUG_TLB
374
375		Enables a temporary TLB entry to be used during boot to work
376		around limitations in e500v1 and e500v2 external debugger
377		support. This reduces the portions of the boot code where
378		breakpoints and single stepping do not work.  The value of this
379		symbol should be set to the TLB1 entry to be used for this
380		purpose.
381
382		CONFIG_SYS_FSL_ERRATUM_A004510
383
384		Enables a workaround for erratum A004510.  If set,
385		then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
386		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
387
388		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
389		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
390
391		Defines one or two SoC revisions (low 8 bits of SVR)
392		for which the A004510 workaround should be applied.
393
394		The rest of SVR is either not relevant to the decision
395		of whether the erratum is present (e.g. p2040 versus
396		p2041) or is implied by the build target, which controls
397		whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
398
399		See Freescale App Note 4493 for more information about
400		this erratum.
401
402		CONFIG_A003399_NOR_WORKAROUND
403		Enables a workaround for IFC erratum A003399. It is only
404		requred during NOR boot.
405
406		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407
408		This is the value to write into CCSR offset 0x18600
409		according to the A004510 workaround.
410
411		CONFIG_SYS_FSL_DSP_DDR_ADDR
412		This value denotes start offset of DDR memory which is
413		connected exclusively to the DSP cores.
414
415		CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
416		This value denotes start offset of M2 memory
417		which is directly connected to the DSP core.
418
419		CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
420		This value denotes start offset of M3 memory which is directly
421		connected to the DSP core.
422
423		CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
424		This value denotes start offset of DSP CCSR space.
425
426		CONFIG_SYS_FSL_DDR_EMU
427		Specify emulator support for DDR. Some DDR features such as
428		deskew training are not available.
429
430- Generic CPU options:
431		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
432
433		Defines the endianess of the CPU. Implementation of those
434		values is arch specific.
435
436- Intel Monahans options:
437		CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
438
439		Defines the Monahans run mode to oscillator
440		ratio. Valid values are 8, 16, 24, 31. The core
441		frequency is this value multiplied by 13 MHz.
442
443		CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
444
445		Defines the Monahans turbo mode to oscillator
446		ratio. Valid values are 1 (default if undefined) and
447		2. The core frequency as calculated above is multiplied
448		by this value.
449
450- MIPS CPU options:
451		CONFIG_SYS_INIT_SP_OFFSET
452
453		Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
454		pointer. This is needed for the temporary stack before
455		relocation.
456
457		CONFIG_SYS_MIPS_CACHE_MODE
458
459		Cache operation mode for the MIPS CPU.
460		See also arch/mips/include/asm/mipsregs.h.
461		Possible values are:
462			CONF_CM_CACHABLE_NO_WA
463			CONF_CM_CACHABLE_WA
464			CONF_CM_UNCACHED
465			CONF_CM_CACHABLE_NONCOHERENT
466			CONF_CM_CACHABLE_CE
467			CONF_CM_CACHABLE_COW
468			CONF_CM_CACHABLE_CUW
469			CONF_CM_CACHABLE_ACCELERATED
470
471		CONFIG_SYS_XWAY_EBU_BOOTCFG
472
473		Special option for Lantiq XWAY SoCs for booting from NOR flash.
474		See also arch/mips/cpu/mips32/start.S.
475
476		CONFIG_XWAY_SWAP_BYTES
477
478		Enable compilation of tools/xway-swap-bytes needed for Lantiq
479		XWAY SoCs for booting from NOR flash. The U-Boot image needs to
480		be swapped if a flash programmer is used.
481
482- ARM options:
483		CONFIG_SYS_EXCEPTION_VECTORS_HIGH
484
485		Select high exception vectors of the ARM core, e.g., do not
486		clear the V bit of the c1 register of CP15.
487
488		CONFIG_SYS_THUMB_BUILD
489
490		Use this flag to build U-Boot using the Thumb instruction
491		set for ARM architectures. Thumb instruction set provides
492		better code density. For ARM architectures that support
493		Thumb2 this flag will result in Thumb2 code generated by
494		GCC.
495
496		CONFIG_ARM_ERRATA_716044
497		CONFIG_ARM_ERRATA_742230
498		CONFIG_ARM_ERRATA_743622
499		CONFIG_ARM_ERRATA_751472
500
501		If set, the workarounds for these ARM errata are applied early
502		during U-Boot startup. Note that these options force the
503		workarounds to be applied; no CPU-type/version detection
504		exists, unlike the similar options in the Linux kernel. Do not
505		set these options unless they apply!
506
507- CPU timer options:
508		CONFIG_SYS_HZ
509
510		The frequency of the timer returned by get_timer().
511		get_timer() must operate in milliseconds and this CONFIG
512		option must be set to 1000.
513
514- Linux Kernel Interface:
515		CONFIG_CLOCKS_IN_MHZ
516
517		U-Boot stores all clock information in Hz
518		internally. For binary compatibility with older Linux
519		kernels (which expect the clocks passed in the
520		bd_info data to be in MHz) the environment variable
521		"clocks_in_mhz" can be defined so that U-Boot
522		converts clock data to MHZ before passing it to the
523		Linux kernel.
524		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
525		"clocks_in_mhz=1" is automatically included in the
526		default environment.
527
528		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]
529
530		When transferring memsize parameter to linux, some versions
531		expect it to be in bytes, others in MB.
532		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
533
534		CONFIG_OF_LIBFDT
535
536		New kernel versions are expecting firmware settings to be
537		passed using flattened device trees (based on open firmware
538		concepts).
539
540		CONFIG_OF_LIBFDT
541		 * New libfdt-based support
542		 * Adds the "fdt" command
543		 * The bootm command automatically updates the fdt
544
545		OF_CPU - The proper name of the cpus node (only required for
546			MPC512X and MPC5xxx based boards).
547		OF_SOC - The proper name of the soc node (only required for
548			MPC512X and MPC5xxx based boards).
549		OF_TBCLK - The timebase frequency.
550		OF_STDOUT_PATH - The path to the console device
551
552		boards with QUICC Engines require OF_QE to set UCC MAC
553		addresses
554
555		CONFIG_OF_BOARD_SETUP
556
557		Board code has addition modification that it wants to make
558		to the flat device tree before handing it off to the kernel
559
560		CONFIG_OF_BOOT_CPU
561
562		This define fills in the correct boot CPU in the boot
563		param header, the default value is zero if undefined.
564
565		CONFIG_OF_IDE_FIXUP
566
567		U-Boot can detect if an IDE device is present or not.
568		If not, and this new config option is activated, U-Boot
569		removes the ATA node from the DTS before booting Linux,
570		so the Linux IDE driver does not probe the device and
571		crash. This is needed for buggy hardware (uc101) where
572		no pull down resistor is connected to the signal IDE5V_DD7.
573
574		CONFIG_MACH_TYPE	[relevant for ARM only][mandatory]
575
576		This setting is mandatory for all boards that have only one
577		machine type and must be used to specify the machine type
578		number as it appears in the ARM machine registry
579		(see http://www.arm.linux.org.uk/developer/machines/).
580		Only boards that have multiple machine types supported
581		in a single configuration file and the machine type is
582		runtime discoverable, do not have to use this setting.
583
584- vxWorks boot parameters:
585
586		bootvx constructs a valid bootline using the following
587		environments variables: bootfile, ipaddr, serverip, hostname.
588		It loads the vxWorks image pointed bootfile.
589
590		CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
591		CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
592		CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
593		CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
594
595		CONFIG_SYS_VXWORKS_ADD_PARAMS
596
597		Add it at the end of the bootline. E.g "u=username pw=secret"
598
599		Note: If a "bootargs" environment is defined, it will overwride
600		the defaults discussed just above.
601
602- Cache Configuration:
603		CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
604		CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
605		CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
606
607- Cache Configuration for ARM:
608		CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
609				      controller
610		CONFIG_SYS_PL310_BASE - Physical base address of PL310
611					controller register space
612
613- Serial Ports:
614		CONFIG_PL010_SERIAL
615
616		Define this if you want support for Amba PrimeCell PL010 UARTs.
617
618		CONFIG_PL011_SERIAL
619
620		Define this if you want support for Amba PrimeCell PL011 UARTs.
621
622		CONFIG_PL011_CLOCK
623
624		If you have Amba PrimeCell PL011 UARTs, set this variable to
625		the clock speed of the UARTs.
626
627		CONFIG_PL01x_PORTS
628
629		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
630		define this to a list of base addresses for each (supported)
631		port. See e.g. include/configs/versatile.h
632
633		CONFIG_PL011_SERIAL_RLCR
634
635		Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
636		have separate receive and transmit line control registers.  Set
637		this variable to initialize the extra register.
638
639		CONFIG_PL011_SERIAL_FLUSH_ON_INIT
640
641		On some platforms (e.g. U8500) U-Boot is loaded by a second stage
642		boot loader that has already initialized the UART.  Define this
643		variable to flush the UART at init time.
644
645
646- Console Interface:
647		Depending on board, define exactly one serial port
648		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
649		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
650		console by defining CONFIG_8xx_CONS_NONE
651
652		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
653		port routines must be defined elsewhere
654		(i.e. serial_init(), serial_getc(), ...)
655
656		CONFIG_CFB_CONSOLE
657		Enables console device for a color framebuffer. Needs following
658		defines (cf. smiLynxEM, i8042)
659			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
660						(default big endian)
661			VIDEO_HW_RECTFILL	graphic chip supports
662						rectangle fill
663						(cf. smiLynxEM)
664			VIDEO_HW_BITBLT		graphic chip supports
665						bit-blit (cf. smiLynxEM)
666			VIDEO_VISIBLE_COLS	visible pixel columns
667						(cols=pitch)
668			VIDEO_VISIBLE_ROWS	visible pixel rows
669			VIDEO_PIXEL_SIZE	bytes per pixel
670			VIDEO_DATA_FORMAT	graphic data format
671						(0-5, cf. cfb_console.c)
672			VIDEO_FB_ADRS		framebuffer address
673			VIDEO_KBD_INIT_FCT	keyboard int fct
674						(i.e. i8042_kbd_init())
675			VIDEO_TSTC_FCT		test char fct
676						(i.e. i8042_tstc)
677			VIDEO_GETC_FCT		get char fct
678						(i.e. i8042_getc)
679			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
680						(requires blink timer
681						cf. i8042.c)
682			CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
683			CONFIG_CONSOLE_TIME	display time/date info in
684						upper right corner
685						(requires CONFIG_CMD_DATE)
686			CONFIG_VIDEO_LOGO	display Linux logo in
687						upper left corner
688			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
689						linux_logo.h for logo.
690						Requires CONFIG_VIDEO_LOGO
691			CONFIG_CONSOLE_EXTRA_INFO
692						additional board info beside
693						the logo
694
695		When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
696		a limited number of ANSI escape sequences (cursor control,
697		erase functions and limited graphics rendition control).
698
699		When CONFIG_CFB_CONSOLE is defined, video console is
700		default i/o. Serial console can be forced with
701		environment 'console=serial'.
702
703		When CONFIG_SILENT_CONSOLE is defined, all console
704		messages (by U-Boot and Linux!) can be silenced with
705		the "silent" environment variable. See
706		doc/README.silent for more information.
707
708- Console Baudrate:
709		CONFIG_BAUDRATE - in bps
710		Select one of the baudrates listed in
711		CONFIG_SYS_BAUDRATE_TABLE, see below.
712		CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
713
714- Console Rx buffer length
715		With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
716		the maximum receive buffer length for the SMC.
717		This option is actual only for 82xx and 8xx possible.
718		If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
719		must be defined, to setup the maximum idle timeout for
720		the SMC.
721
722- Pre-Console Buffer:
723		Prior to the console being initialised (i.e. serial UART
724		initialised etc) all console output is silently discarded.
725		Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
726		buffer any console messages prior to the console being
727		initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
728		bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
729		a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
730		bytes are output before the console is initialised, the
731		earlier bytes are discarded.
732
733		'Sane' compilers will generate smaller code if
734		CONFIG_PRE_CON_BUF_SZ is a power of 2
735
736- Safe printf() functions
737		Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
738		the printf() functions. These are defined in
739		include/vsprintf.h and include snprintf(), vsnprintf() and
740		so on. Code size increase is approximately 300-500 bytes.
741		If this option is not given then these functions will
742		silently discard their buffer size argument - this means
743		you are not getting any overflow checking in this case.
744
745- Boot Delay:	CONFIG_BOOTDELAY - in seconds
746		Delay before automatically booting the default image;
747		set to -1 to disable autoboot.
748		set to -2 to autoboot with no delay and not check for abort
749		(even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
750
751		See doc/README.autoboot for these options that
752		work with CONFIG_BOOTDELAY. None are required.
753		CONFIG_BOOT_RETRY_TIME
754		CONFIG_BOOT_RETRY_MIN
755		CONFIG_AUTOBOOT_KEYED
756		CONFIG_AUTOBOOT_PROMPT
757		CONFIG_AUTOBOOT_DELAY_STR
758		CONFIG_AUTOBOOT_STOP_STR
759		CONFIG_AUTOBOOT_DELAY_STR2
760		CONFIG_AUTOBOOT_STOP_STR2
761		CONFIG_ZERO_BOOTDELAY_CHECK
762		CONFIG_RESET_TO_RETRY
763
764- Autoboot Command:
765		CONFIG_BOOTCOMMAND
766		Only needed when CONFIG_BOOTDELAY is enabled;
767		define a command string that is automatically executed
768		when no character is read on the console interface
769		within "Boot Delay" after reset.
770
771		CONFIG_BOOTARGS
772		This can be used to pass arguments to the bootm
773		command. The value of CONFIG_BOOTARGS goes into the
774		environment value "bootargs".
775
776		CONFIG_RAMBOOT and CONFIG_NFSBOOT
777		The value of these goes into the environment as
778		"ramboot" and "nfsboot" respectively, and can be used
779		as a convenience, when switching between booting from
780		RAM and NFS.
781
782- Pre-Boot Commands:
783		CONFIG_PREBOOT
784
785		When this option is #defined, the existence of the
786		environment variable "preboot" will be checked
787		immediately before starting the CONFIG_BOOTDELAY
788		countdown and/or running the auto-boot command resp.
789		entering interactive mode.
790
791		This feature is especially useful when "preboot" is
792		automatically generated or modified. For an example
793		see the LWMON board specific code: here "preboot" is
794		modified when the user holds down a certain
795		combination of keys on the (special) keyboard when
796		booting the systems
797
798- Serial Download Echo Mode:
799		CONFIG_LOADS_ECHO
800		If defined to 1, all characters received during a
801		serial download (using the "loads" command) are
802		echoed back. This might be needed by some terminal
803		emulations (like "cu"), but may as well just take
804		time on others. This setting #define's the initial
805		value of the "loads_echo" environment variable.
806
807- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
808		CONFIG_KGDB_BAUDRATE
809		Select one of the baudrates listed in
810		CONFIG_SYS_BAUDRATE_TABLE, see below.
811
812- Monitor Functions:
813		Monitor commands can be included or excluded
814		from the build by using the #include files
815		<config_cmd_all.h> and #undef'ing unwanted
816		commands, or using <config_cmd_default.h>
817		and augmenting with additional #define's
818		for wanted commands.
819
820		The default command configuration includes all commands
821		except those marked below with a "*".
822
823		CONFIG_CMD_ASKENV	* ask for env variable
824		CONFIG_CMD_BDI		  bdinfo
825		CONFIG_CMD_BEDBUG	* Include BedBug Debugger
826		CONFIG_CMD_BMP		* BMP support
827		CONFIG_CMD_BSP		* Board specific commands
828		CONFIG_CMD_BOOTD	  bootd
829		CONFIG_CMD_CACHE	* icache, dcache
830		CONFIG_CMD_CONSOLE	  coninfo
831		CONFIG_CMD_CRC32	* crc32
832		CONFIG_CMD_DATE		* support for RTC, date/time...
833		CONFIG_CMD_DHCP		* DHCP support
834		CONFIG_CMD_DIAG		* Diagnostics
835		CONFIG_CMD_DS4510	* ds4510 I2C gpio commands
836		CONFIG_CMD_DS4510_INFO	* ds4510 I2C info command
837		CONFIG_CMD_DS4510_MEM	* ds4510 I2C eeprom/sram commansd
838		CONFIG_CMD_DS4510_RST	* ds4510 I2C rst command
839		CONFIG_CMD_DTT		* Digital Therm and Thermostat
840		CONFIG_CMD_ECHO		  echo arguments
841		CONFIG_CMD_EDITENV	  edit env variable
842		CONFIG_CMD_EEPROM	* EEPROM read/write support
843		CONFIG_CMD_ELF		* bootelf, bootvx
844		CONFIG_CMD_ENV_CALLBACK	* display details about env callbacks
845		CONFIG_CMD_ENV_FLAGS	* display details about env flags
846		CONFIG_CMD_EXPORTENV	* export the environment
847		CONFIG_CMD_EXT2		* ext2 command support
848		CONFIG_CMD_EXT4		* ext4 command support
849		CONFIG_CMD_SAVEENV	  saveenv
850		CONFIG_CMD_FDC		* Floppy Disk Support
851		CONFIG_CMD_FAT		* FAT command support
852		CONFIG_CMD_FDOS		* Dos diskette Support
853		CONFIG_CMD_FLASH	  flinfo, erase, protect
854		CONFIG_CMD_FPGA		  FPGA device initialization support
855		CONFIG_CMD_FUSE		* Device fuse support
856		CONFIG_CMD_GETTIME	* Get time since boot
857		CONFIG_CMD_GO		* the 'go' command (exec code)
858		CONFIG_CMD_GREPENV	* search environment
859		CONFIG_CMD_HASH		* calculate hash / digest
860		CONFIG_CMD_HWFLOW	* RTS/CTS hw flow control
861		CONFIG_CMD_I2C		* I2C serial bus support
862		CONFIG_CMD_IDE		* IDE harddisk support
863		CONFIG_CMD_IMI		  iminfo
864		CONFIG_CMD_IMLS		  List all images found in NOR flash
865		CONFIG_CMD_IMLS_NAND	* List all images found in NAND flash
866		CONFIG_CMD_IMMAP	* IMMR dump support
867		CONFIG_CMD_IMPORTENV	* import an environment
868		CONFIG_CMD_INI		* import data from an ini file into the env
869		CONFIG_CMD_IRQ		* irqinfo
870		CONFIG_CMD_ITEST	  Integer/string test of 2 values
871		CONFIG_CMD_JFFS2	* JFFS2 Support
872		CONFIG_CMD_KGDB		* kgdb
873		CONFIG_CMD_LDRINFO	* ldrinfo (display Blackfin loader)
874		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
875					  (169.254.*.*)
876		CONFIG_CMD_LOADB	  loadb
877		CONFIG_CMD_LOADS	  loads
878		CONFIG_CMD_MD5SUM	* print md5 message digest
879					  (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
880		CONFIG_CMD_MEMINFO	* Display detailed memory information
881		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
882					  loop, loopw
883		CONFIG_CMD_MEMTEST	* mtest
884		CONFIG_CMD_MISC		  Misc functions like sleep etc
885		CONFIG_CMD_MMC		* MMC memory mapped support
886		CONFIG_CMD_MII		* MII utility commands
887		CONFIG_CMD_MTDPARTS	* MTD partition support
888		CONFIG_CMD_NAND		* NAND support
889		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
890		CONFIG_CMD_NFS		  NFS support
891		CONFIG_CMD_PCA953X	* PCA953x I2C gpio commands
892		CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
893		CONFIG_CMD_PCI		* pciinfo
894		CONFIG_CMD_PCMCIA		* PCMCIA support
895		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
896					  host
897		CONFIG_CMD_PORTIO	* Port I/O
898		CONFIG_CMD_READ		* Read raw data from partition
899		CONFIG_CMD_REGINFO	* Register dump
900		CONFIG_CMD_RUN		  run command in env variable
901		CONFIG_CMD_SANDBOX	* sb command to access sandbox features
902		CONFIG_CMD_SAVES	* save S record dump
903		CONFIG_CMD_SCSI		* SCSI Support
904		CONFIG_CMD_SDRAM	* print SDRAM configuration information
905					  (requires CONFIG_CMD_I2C)
906		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
907					  (4xx only)
908		CONFIG_CMD_SF		* Read/write/erase SPI NOR flash
909		CONFIG_CMD_SHA1SUM	* print sha1 memory digest
910					  (requires CONFIG_CMD_MEMORY)
911		CONFIG_CMD_SOFTSWITCH	* Soft switch setting command for BF60x
912		CONFIG_CMD_SOURCE	  "source" command Support
913		CONFIG_CMD_SPI		* SPI serial bus support
914		CONFIG_CMD_TFTPSRV	* TFTP transfer in server mode
915		CONFIG_CMD_TFTPPUT	* TFTP put command (upload)
916		CONFIG_CMD_TIME		* run command and report execution time (ARM specific)
917		CONFIG_CMD_TIMER	* access to the system tick timer
918		CONFIG_CMD_USB		* USB support
919		CONFIG_CMD_CDP		* Cisco Discover Protocol support
920		CONFIG_CMD_MFSL		* Microblaze FSL support
921		CONFIG_CMD_XIMG		  Load part of Multi Image
922
923
924		EXAMPLE: If you want all functions except of network
925		support you can write:
926
927		#include "config_cmd_all.h"
928		#undef CONFIG_CMD_NET
929
930	Other Commands:
931		fdt (flattened device tree) command: CONFIG_OF_LIBFDT
932
933	Note:	Don't enable the "icache" and "dcache" commands
934		(configuration option CONFIG_CMD_CACHE) unless you know
935		what you (and your U-Boot users) are doing. Data
936		cache cannot be enabled on systems like the 8xx or
937		8260 (where accesses to the IMMR region must be
938		uncached), and it cannot be disabled on all other
939		systems where we (mis-) use the data cache to hold an
940		initial stack and some data.
941
942
943		XXX - this list needs to get updated!
944
945- Regular expression support:
946		CONFIG_REGEX
947		If this variable is defined, U-Boot is linked against
948		the SLRE (Super Light Regular Expression) library,
949		which adds regex support to some commands, as for
950		example "env grep" and "setexpr".
951
952- Device tree:
953		CONFIG_OF_CONTROL
954		If this variable is defined, U-Boot will use a device tree
955		to configure its devices, instead of relying on statically
956		compiled #defines in the board file. This option is
957		experimental and only available on a few boards. The device
958		tree is available in the global data as gd->fdt_blob.
959
960		U-Boot needs to get its device tree from somewhere. This can
961		be done using one of the two options below:
962
963		CONFIG_OF_EMBED
964		If this variable is defined, U-Boot will embed a device tree
965		binary in its image. This device tree file should be in the
966		board directory and called <soc>-<board>.dts. The binary file
967		is then picked up in board_init_f() and made available through
968		the global data structure as gd->blob.
969
970		CONFIG_OF_SEPARATE
971		If this variable is defined, U-Boot will build a device tree
972		binary. It will be called u-boot.dtb. Architecture-specific
973		code will locate it at run-time. Generally this works by:
974
975			cat u-boot.bin u-boot.dtb >image.bin
976
977		and in fact, U-Boot does this for you, creating a file called
978		u-boot-dtb.bin which is useful in the common case. You can
979		still use the individual files if you need something more
980		exotic.
981
982- Watchdog:
983		CONFIG_WATCHDOG
984		If this variable is defined, it enables watchdog
985		support for the SoC. There must be support in the SoC
986		specific code for a watchdog. For the 8xx and 8260
987		CPUs, the SIU Watchdog feature is enabled in the SYPCR
988		register.  When supported for a specific SoC is
989		available, then no further board specific code should
990		be needed to use it.
991
992		CONFIG_HW_WATCHDOG
993		When using a watchdog circuitry external to the used
994		SoC, then define this variable and provide board
995		specific code for the "hw_watchdog_reset" function.
996
997- U-Boot Version:
998		CONFIG_VERSION_VARIABLE
999		If this variable is defined, an environment variable
1000		named "ver" is created by U-Boot showing the U-Boot
1001		version as printed by the "version" command.
1002		Any change to this variable will be reverted at the
1003		next reset.
1004
1005- Real-Time Clock:
1006
1007		When CONFIG_CMD_DATE is selected, the type of the RTC
1008		has to be selected, too. Define exactly one of the
1009		following options:
1010
1011		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
1012		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
1013		CONFIG_RTC_MC13XXX	- use MC13783 or MC13892 RTC
1014		CONFIG_RTC_MC146818	- use MC146818 RTC
1015		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
1016		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
1017		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
1018		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
1019		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
1020		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
1021		CONFIG_SYS_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
1022		CONFIG_SYS_RV3029_TCR	- enable trickle charger on
1023					  RV3029 RTC.
1024
1025		Note that if the RTC uses I2C, then the I2C interface
1026		must also be configured. See I2C Support, below.
1027
1028- GPIO Support:
1029		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
1030		CONFIG_PCA953X_INFO	- enable pca953x info command
1031
1032		The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1033		chip-ngpio pairs that tell the PCA953X driver the number of
1034		pins supported by a particular chip.
1035
1036		Note that if the GPIO device uses I2C, then the I2C interface
1037		must also be configured. See I2C Support, below.
1038
1039- Timestamp Support:
1040
1041		When CONFIG_TIMESTAMP is selected, the timestamp
1042		(date and time) of an image is printed by image
1043		commands like bootm or iminfo. This option is
1044		automatically enabled when you select CONFIG_CMD_DATE .
1045
1046- Partition Labels (disklabels) Supported:
1047		Zero or more of the following:
1048		CONFIG_MAC_PARTITION   Apple's MacOS partition table.
1049		CONFIG_DOS_PARTITION   MS Dos partition table, traditional on the
1050				       Intel architecture, USB sticks, etc.
1051		CONFIG_ISO_PARTITION   ISO partition table, used on CDROM etc.
1052		CONFIG_EFI_PARTITION   GPT partition table, common when EFI is the
1053				       bootloader.  Note 2TB partition limit; see
1054				       disk/part_efi.c
1055		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.
1056
1057		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1058		CONFIG_CMD_SCSI) you must configure support for at
1059		least one non-MTD partition type as well.
1060
1061- IDE Reset method:
1062		CONFIG_IDE_RESET_ROUTINE - this is defined in several
1063		board configurations files but used nowhere!
1064
1065		CONFIG_IDE_RESET - is this is defined, IDE Reset will
1066		be performed by calling the function
1067			ide_set_reset(int reset)
1068		which has to be defined in a board specific file
1069
1070- ATAPI Support:
1071		CONFIG_ATAPI
1072
1073		Set this to enable ATAPI support.
1074
1075- LBA48 Support
1076		CONFIG_LBA48
1077
1078		Set this to enable support for disks larger than 137GB
1079		Also look at CONFIG_SYS_64BIT_LBA.
1080		Whithout these , LBA48 support uses 32bit variables and will 'only'
1081		support disks up to 2.1TB.
1082
1083		CONFIG_SYS_64BIT_LBA:
1084			When enabled, makes the IDE subsystem use 64bit sector addresses.
1085			Default is 32bit.
1086
1087- SCSI Support:
1088		At the moment only there is only support for the
1089		SYM53C8XX SCSI controller; define
1090		CONFIG_SCSI_SYM53C8XX to enable it.
1091
1092		CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1093		CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1094		CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1095		maximum numbers of LUNs, SCSI ID's and target
1096		devices.
1097		CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1098
1099		The environment variable 'scsidevs' is set to the number of
1100		SCSI devices found during the last scan.
1101
1102- NETWORK Support (PCI):
1103		CONFIG_E1000
1104		Support for Intel 8254x/8257x gigabit chips.
1105
1106		CONFIG_E1000_SPI
1107		Utility code for direct access to the SPI bus on Intel 8257x.
1108		This does not do anything useful unless you set at least one
1109		of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1110
1111		CONFIG_E1000_SPI_GENERIC
1112		Allow generic access to the SPI bus on the Intel 8257x, for
1113		example with the "sspi" command.
1114
1115		CONFIG_CMD_E1000
1116		Management command for E1000 devices.  When used on devices
1117		with SPI support you can reprogram the EEPROM from U-Boot.
1118
1119		CONFIG_E1000_FALLBACK_MAC
1120		default MAC for empty EEPROM after production.
1121
1122		CONFIG_EEPRO100
1123		Support for Intel 82557/82559/82559ER chips.
1124		Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1125		write routine for first time initialisation.
1126
1127		CONFIG_TULIP
1128		Support for Digital 2114x chips.
1129		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1130		modem chip initialisation (KS8761/QS6611).
1131
1132		CONFIG_NATSEMI
1133		Support for National dp83815 chips.
1134
1135		CONFIG_NS8382X
1136		Support for National dp8382[01] gigabit chips.
1137
1138- NETWORK Support (other):
1139
1140		CONFIG_DRIVER_AT91EMAC
1141		Support for AT91RM9200 EMAC.
1142
1143			CONFIG_RMII
1144			Define this to use reduced MII inteface
1145
1146			CONFIG_DRIVER_AT91EMAC_QUIET
1147			If this defined, the driver is quiet.
1148			The driver doen't show link status messages.
1149
1150		CONFIG_CALXEDA_XGMAC
1151		Support for the Calxeda XGMAC device
1152
1153		CONFIG_LAN91C96
1154		Support for SMSC's LAN91C96 chips.
1155
1156			CONFIG_LAN91C96_BASE
1157			Define this to hold the physical address
1158			of the LAN91C96's I/O space
1159
1160			CONFIG_LAN91C96_USE_32_BIT
1161			Define this to enable 32 bit addressing
1162
1163		CONFIG_SMC91111
1164		Support for SMSC's LAN91C111 chip
1165
1166			CONFIG_SMC91111_BASE
1167			Define this to hold the physical address
1168			of the device (I/O space)
1169
1170			CONFIG_SMC_USE_32_BIT
1171			Define this if data bus is 32 bits
1172
1173			CONFIG_SMC_USE_IOFUNCS
1174			Define this to use i/o functions instead of macros
1175			(some hardware wont work with macros)
1176
1177		CONFIG_DRIVER_TI_EMAC
1178		Support for davinci emac
1179
1180			CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1181			Define this if you have more then 3 PHYs.
1182
1183		CONFIG_FTGMAC100
1184		Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1185
1186			CONFIG_FTGMAC100_EGIGA
1187			Define this to use GE link update with gigabit PHY.
1188			Define this if FTGMAC100 is connected to gigabit PHY.
1189			If your system has 10/100 PHY only, it might not occur
1190			wrong behavior. Because PHY usually return timeout or
1191			useless data when polling gigabit status and gigabit
1192			control registers. This behavior won't affect the
1193			correctnessof 10/100 link speed update.
1194
1195		CONFIG_SMC911X
1196		Support for SMSC's LAN911x and LAN921x chips
1197
1198			CONFIG_SMC911X_BASE
1199			Define this to hold the physical address
1200			of the device (I/O space)
1201
1202			CONFIG_SMC911X_32_BIT
1203			Define this if data bus is 32 bits
1204
1205			CONFIG_SMC911X_16_BIT
1206			Define this if data bus is 16 bits. If your processor
1207			automatically converts one 32 bit word to two 16 bit
1208			words you may also try CONFIG_SMC911X_32_BIT.
1209
1210		CONFIG_SH_ETHER
1211		Support for Renesas on-chip Ethernet controller
1212
1213			CONFIG_SH_ETHER_USE_PORT
1214			Define the number of ports to be used
1215
1216			CONFIG_SH_ETHER_PHY_ADDR
1217			Define the ETH PHY's address
1218
1219			CONFIG_SH_ETHER_CACHE_WRITEBACK
1220			If this option is set, the driver enables cache flush.
1221
1222- TPM Support:
1223		CONFIG_TPM
1224		Support TPM devices.
1225
1226		CONFIG_TPM_TIS_I2C
1227		Support for i2c bus TPM devices. Only one device
1228		per system is supported at this time.
1229
1230			CONFIG_TPM_TIS_I2C_BUS_NUMBER
1231			Define the the i2c bus number for the TPM device
1232
1233			CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1234			Define the TPM's address on the i2c bus
1235
1236			CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1237			Define the burst count bytes upper limit
1238
1239		CONFIG_TPM_ATMEL_TWI
1240		Support for Atmel TWI TPM device. Requires I2C support.
1241
1242		CONFIG_TPM_TIS_LPC
1243		Support for generic parallel port TPM devices. Only one device
1244		per system is supported at this time.
1245
1246			CONFIG_TPM_TIS_BASE_ADDRESS
1247			Base address where the generic TPM device is mapped
1248			to. Contemporary x86 systems usually map it at
1249			0xfed40000.
1250
1251		CONFIG_CMD_TPM
1252		Add tpm monitor functions.
1253		Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1254		provides monitor access to authorized functions.
1255
1256		CONFIG_TPM
1257		Define this to enable the TPM support library which provides
1258		functional interfaces to some TPM commands.
1259		Requires support for a TPM device.
1260
1261		CONFIG_TPM_AUTH_SESSIONS
1262		Define this to enable authorized functions in the TPM library.
1263		Requires CONFIG_TPM and CONFIG_SHA1.
1264
1265- USB Support:
1266		At the moment only the UHCI host controller is
1267		supported (PIP405, MIP405, MPC5200); define
1268		CONFIG_USB_UHCI to enable it.
1269		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1270		and define CONFIG_USB_STORAGE to enable the USB
1271		storage devices.
1272		Note:
1273		Supported are USB Keyboards and USB Floppy drives
1274		(TEAC FD-05PUB).
1275		MPC5200 USB requires additional defines:
1276			CONFIG_USB_CLOCK
1277				for 528 MHz Clock: 0x0001bbbb
1278			CONFIG_PSC3_USB
1279				for USB on PSC3
1280			CONFIG_USB_CONFIG
1281				for differential drivers: 0x00001000
1282				for single ended drivers: 0x00005000
1283				for differential drivers on PSC3: 0x00000100
1284				for single ended drivers on PSC3: 0x00004100
1285			CONFIG_SYS_USB_EVENT_POLL
1286				May be defined to allow interrupt polling
1287				instead of using asynchronous interrupts
1288
1289		CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1290		txfilltuning field in the EHCI controller on reset.
1291
1292		CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1293		interval for usb hub power-on delay.(minimum 100msec)
1294
1295- USB Device:
1296		Define the below if you wish to use the USB console.
1297		Once firmware is rebuilt from a serial console issue the
1298		command "setenv stdin usbtty; setenv stdout usbtty" and
1299		attach your USB cable. The Unix command "dmesg" should print
1300		it has found a new device. The environment variable usbtty
1301		can be set to gserial or cdc_acm to enable your device to
1302		appear to a USB host as a Linux gserial device or a
1303		Common Device Class Abstract Control Model serial device.
1304		If you select usbtty = gserial you should be able to enumerate
1305		a Linux host by
1306		# modprobe usbserial vendor=0xVendorID product=0xProductID
1307		else if using cdc_acm, simply setting the environment
1308		variable usbtty to be cdc_acm should suffice. The following
1309		might be defined in YourBoardName.h
1310
1311			CONFIG_USB_DEVICE
1312			Define this to build a UDC device
1313
1314			CONFIG_USB_TTY
1315			Define this to have a tty type of device available to
1316			talk to the UDC device
1317
1318			CONFIG_USBD_HS
1319			Define this to enable the high speed support for usb
1320			device and usbtty. If this feature is enabled, a routine
1321			int is_usbd_high_speed(void)
1322			also needs to be defined by the driver to dynamically poll
1323			whether the enumeration has succeded at high speed or full
1324			speed.
1325
1326			CONFIG_SYS_CONSOLE_IS_IN_ENV
1327			Define this if you want stdin, stdout &/or stderr to
1328			be set to usbtty.
1329
1330			mpc8xx:
1331				CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1332				Derive USB clock from external clock "blah"
1333				- CONFIG_SYS_USB_EXTC_CLK 0x02
1334
1335				CONFIG_SYS_USB_BRG_CLK 0xBLAH
1336				Derive USB clock from brgclk
1337				- CONFIG_SYS_USB_BRG_CLK 0x04
1338
1339		If you have a USB-IF assigned VendorID then you may wish to
1340		define your own vendor specific values either in BoardName.h
1341		or directly in usbd_vendor_info.h. If you don't define
1342		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1343		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1344		should pretend to be a Linux device to it's target host.
1345
1346			CONFIG_USBD_MANUFACTURER
1347			Define this string as the name of your company for
1348			- CONFIG_USBD_MANUFACTURER "my company"
1349
1350			CONFIG_USBD_PRODUCT_NAME
1351			Define this string as the name of your product
1352			- CONFIG_USBD_PRODUCT_NAME "acme usb device"
1353
1354			CONFIG_USBD_VENDORID
1355			Define this as your assigned Vendor ID from the USB
1356			Implementors Forum. This *must* be a genuine Vendor ID
1357			to avoid polluting the USB namespace.
1358			- CONFIG_USBD_VENDORID 0xFFFF
1359
1360			CONFIG_USBD_PRODUCTID
1361			Define this as the unique Product ID
1362			for your device
1363			- CONFIG_USBD_PRODUCTID 0xFFFF
1364
1365- ULPI Layer Support:
1366		The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1367		the generic ULPI layer. The generic layer accesses the ULPI PHY
1368		via the platform viewport, so you need both the genric layer and
1369		the viewport enabled. Currently only Chipidea/ARC based
1370		viewport is supported.
1371		To enable the ULPI layer support, define CONFIG_USB_ULPI and
1372		CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1373		If your ULPI phy needs a different reference clock than the
1374		standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1375		the appropriate value in Hz.
1376
1377- MMC Support:
1378		The MMC controller on the Intel PXA is supported. To
1379		enable this define CONFIG_MMC. The MMC can be
1380		accessed from the boot prompt by mapping the device
1381		to physical memory similar to flash. Command line is
1382		enabled with CONFIG_CMD_MMC. The MMC driver also works with
1383		the FAT fs. This is enabled with CONFIG_CMD_FAT.
1384
1385		CONFIG_SH_MMCIF
1386		Support for Renesas on-chip MMCIF controller
1387
1388			CONFIG_SH_MMCIF_ADDR
1389			Define the base address of MMCIF registers
1390
1391			CONFIG_SH_MMCIF_CLK
1392			Define the clock frequency for MMCIF
1393
1394- USB Device Firmware Update (DFU) class support:
1395		CONFIG_DFU_FUNCTION
1396		This enables the USB portion of the DFU USB class
1397
1398		CONFIG_CMD_DFU
1399		This enables the command "dfu" which is used to have
1400		U-Boot create a DFU class device via USB.  This command
1401		requires that the "dfu_alt_info" environment variable be
1402		set and define the alt settings to expose to the host.
1403
1404		CONFIG_DFU_MMC
1405		This enables support for exposing (e)MMC devices via DFU.
1406
1407		CONFIG_DFU_NAND
1408		This enables support for exposing NAND devices via DFU.
1409
1410		CONFIG_DFU_RAM
1411		This enables support for exposing RAM via DFU.
1412		Note: DFU spec refer to non-volatile memory usage, but
1413		allow usages beyond the scope of spec - here RAM usage,
1414		one that would help mostly the developer.
1415
1416		CONFIG_SYS_DFU_DATA_BUF_SIZE
1417		Dfu transfer uses a buffer before writing data to the
1418		raw storage device. Make the size (in bytes) of this buffer
1419		configurable. The size of this buffer is also configurable
1420		through the "dfu_bufsiz" environment variable.
1421
1422		CONFIG_SYS_DFU_MAX_FILE_SIZE
1423		When updating files rather than the raw storage device,
1424		we use a static buffer to copy the file into and then write
1425		the buffer once we've been given the whole file.  Define
1426		this to the maximum filesize (in bytes) for the buffer.
1427		Default is 4 MiB if undefined.
1428
1429- Journaling Flash filesystem support:
1430		CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1431		CONFIG_JFFS2_NAND_DEV
1432		Define these for a default partition on a NAND device
1433
1434		CONFIG_SYS_JFFS2_FIRST_SECTOR,
1435		CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1436		Define these for a default partition on a NOR device
1437
1438		CONFIG_SYS_JFFS_CUSTOM_PART
1439		Define this to create an own partition. You have to provide a
1440		function struct part_info* jffs2_part_info(int part_num)
1441
1442		If you define only one JFFS2 partition you may also want to
1443		#define CONFIG_SYS_JFFS_SINGLE_PART	1
1444		to disable the command chpart. This is the default when you
1445		have not defined a custom partition
1446
1447- FAT(File Allocation Table) filesystem write function support:
1448		CONFIG_FAT_WRITE
1449
1450		Define this to enable support for saving memory data as a
1451		file in FAT formatted partition.
1452
1453		This will also enable the command "fatwrite" enabling the
1454		user to write files to FAT.
1455
1456CBFS (Coreboot Filesystem) support
1457		CONFIG_CMD_CBFS
1458
1459		Define this to enable support for reading from a Coreboot
1460		filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1461		and cbfsload.
1462
1463- Keyboard Support:
1464		CONFIG_ISA_KEYBOARD
1465
1466		Define this to enable standard (PC-Style) keyboard
1467		support
1468
1469		CONFIG_I8042_KBD
1470		Standard PC keyboard driver with US (is default) and
1471		GERMAN key layout (switch via environment 'keymap=de') support.
1472		Export function i8042_kbd_init, i8042_tstc and i8042_getc
1473		for cfb_console. Supports cursor blinking.
1474
1475		CONFIG_CROS_EC_KEYB
1476		Enables a Chrome OS keyboard using the CROS_EC interface.
1477		This uses CROS_EC to communicate with a second microcontroller
1478		which provides key scans on request.
1479
1480- Video support:
1481		CONFIG_VIDEO
1482
1483		Define this to enable video support (for output to
1484		video).
1485
1486		CONFIG_VIDEO_CT69000
1487
1488		Enable Chips & Technologies 69000 Video chip
1489
1490		CONFIG_VIDEO_SMI_LYNXEM
1491		Enable Silicon Motion SMI 712/710/810 Video chip. The
1492		video output is selected via environment 'videoout'
1493		(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1494		assumed.
1495
1496		For the CT69000 and SMI_LYNXEM drivers, videomode is
1497		selected via environment 'videomode'. Two different ways
1498		are possible:
1499		- "videomode=num"   'num' is a standard LiLo mode numbers.
1500		Following standard modes are supported	(* is default):
1501
1502		      Colors	640x480 800x600 1024x768 1152x864 1280x1024
1503		-------------+---------------------------------------------
1504		      8 bits |	0x301*	0x303	 0x305	  0x161	    0x307
1505		     15 bits |	0x310	0x313	 0x316	  0x162	    0x319
1506		     16 bits |	0x311	0x314	 0x317	  0x163	    0x31A
1507		     24 bits |	0x312	0x315	 0x318	    ?	    0x31B
1508		-------------+---------------------------------------------
1509		(i.e. setenv videomode 317; saveenv; reset;)
1510
1511		- "videomode=bootargs" all the video parameters are parsed
1512		from the bootargs. (See drivers/video/videomodes.c)
1513
1514
1515		CONFIG_VIDEO_SED13806
1516		Enable Epson SED13806 driver. This driver supports 8bpp
1517		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1518		or CONFIG_VIDEO_SED13806_16BPP
1519
1520		CONFIG_FSL_DIU_FB
1521		Enable the Freescale DIU video driver.	Reference boards for
1522		SOCs that have a DIU should define this macro to enable DIU
1523		support, and should also define these other macros:
1524
1525			CONFIG_SYS_DIU_ADDR
1526			CONFIG_VIDEO
1527			CONFIG_CMD_BMP
1528			CONFIG_CFB_CONSOLE
1529			CONFIG_VIDEO_SW_CURSOR
1530			CONFIG_VGA_AS_SINGLE_DEVICE
1531			CONFIG_VIDEO_LOGO
1532			CONFIG_VIDEO_BMP_LOGO
1533
1534		The DIU driver will look for the 'video-mode' environment
1535		variable, and if defined, enable the DIU as a console during
1536		boot.  See the documentation file README.video for a
1537		description of this variable.
1538
1539		CONFIG_VIDEO_VGA
1540
1541		Enable the VGA video / BIOS for x86. The alternative if you
1542		are using coreboot is to use the coreboot frame buffer
1543		driver.
1544
1545
1546- Keyboard Support:
1547		CONFIG_KEYBOARD
1548
1549		Define this to enable a custom keyboard support.
1550		This simply calls drv_keyboard_init() which must be
1551		defined in your board-specific files.
1552		The only board using this so far is RBC823.
1553
1554- LCD Support:	CONFIG_LCD
1555
1556		Define this to enable LCD support (for output to LCD
1557		display); also select one of the supported displays
1558		by defining one of these:
1559
1560		CONFIG_ATMEL_LCD:
1561
1562			HITACHI TX09D70VM1CCA, 3.5", 240x320.
1563
1564		CONFIG_NEC_NL6448AC33:
1565
1566			NEC NL6448AC33-18. Active, color, single scan.
1567
1568		CONFIG_NEC_NL6448BC20
1569
1570			NEC NL6448BC20-08. 6.5", 640x480.
1571			Active, color, single scan.
1572
1573		CONFIG_NEC_NL6448BC33_54
1574
1575			NEC NL6448BC33-54. 10.4", 640x480.
1576			Active, color, single scan.
1577
1578		CONFIG_SHARP_16x9
1579
1580			Sharp 320x240. Active, color, single scan.
1581			It isn't 16x9, and I am not sure what it is.
1582
1583		CONFIG_SHARP_LQ64D341
1584
1585			Sharp LQ64D341 display, 640x480.
1586			Active, color, single scan.
1587
1588		CONFIG_HLD1045
1589
1590			HLD1045 display, 640x480.
1591			Active, color, single scan.
1592
1593		CONFIG_OPTREX_BW
1594
1595			Optrex	 CBL50840-2 NF-FW 99 22 M5
1596			or
1597			Hitachi	 LMG6912RPFC-00T
1598			or
1599			Hitachi	 SP14Q002
1600
1601			320x240. Black & white.
1602
1603		Normally display is black on white background; define
1604		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1605
1606		CONFIG_LCD_ALIGNMENT
1607
1608		Normally the LCD is page-aligned (tyically 4KB). If this is
1609		defined then the LCD will be aligned to this value instead.
1610		For ARM it is sometimes useful to use MMU_SECTION_SIZE
1611		here, since it is cheaper to change data cache settings on
1612		a per-section basis.
1613
1614		CONFIG_CONSOLE_SCROLL_LINES
1615
1616		When the console need to be scrolled, this is the number of
1617		lines to scroll by. It defaults to 1. Increasing this makes
1618		the console jump but can help speed up operation when scrolling
1619		is slow.
1620
1621		CONFIG_LCD_BMP_RLE8
1622
1623		Support drawing of RLE8-compressed bitmaps on the LCD.
1624
1625		CONFIG_I2C_EDID
1626
1627		Enables an 'i2c edid' command which can read EDID
1628		information over I2C from an attached LCD display.
1629
1630- Splash Screen Support: CONFIG_SPLASH_SCREEN
1631
1632		If this option is set, the environment is checked for
1633		a variable "splashimage". If found, the usual display
1634		of logo, copyright and system information on the LCD
1635		is suppressed and the BMP image at the address
1636		specified in "splashimage" is loaded instead. The
1637		console is redirected to the "nulldev", too. This
1638		allows for a "silent" boot where a splash screen is
1639		loaded very quickly after power-on.
1640
1641		CONFIG_SPLASHIMAGE_GUARD
1642
1643		If this option is set, then U-Boot will prevent the environment
1644		variable "splashimage" from being set to a problematic address
1645		(see README.displaying-bmps and README.arm-unaligned-accesses).
1646		This option is useful for targets where, due to alignment
1647		restrictions, an improperly aligned BMP image will cause a data
1648		abort. If you think you will not have problems with unaligned
1649		accesses (for example because your toolchain prevents them)
1650		there is no need to set this option.
1651
1652		CONFIG_SPLASH_SCREEN_ALIGN
1653
1654		If this option is set the splash image can be freely positioned
1655		on the screen. Environment variable "splashpos" specifies the
1656		position as "x,y". If a positive number is given it is used as
1657		number of pixel from left/top. If a negative number is given it
1658		is used as number of pixel from right/bottom. You can also
1659		specify 'm' for centering the image.
1660
1661		Example:
1662		setenv splashpos m,m
1663			=> image at center of screen
1664
1665		setenv splashpos 30,20
1666			=> image at x = 30 and y = 20
1667
1668		setenv splashpos -10,m
1669			=> vertically centered image
1670			   at x = dspWidth - bmpWidth - 9
1671
1672- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1673
1674		If this option is set, additionally to standard BMP
1675		images, gzipped BMP images can be displayed via the
1676		splashscreen support or the bmp command.
1677
1678- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1679
1680		If this option is set, 8-bit RLE compressed BMP images
1681		can be displayed via the splashscreen support or the
1682		bmp command.
1683
1684- Do compresssing for memory range:
1685		CONFIG_CMD_ZIP
1686
1687		If this option is set, it would use zlib deflate method
1688		to compress the specified memory at its best effort.
1689
1690- Compression support:
1691		CONFIG_GZIP
1692
1693		Enabled by default to support gzip compressed images.
1694
1695		CONFIG_BZIP2
1696
1697		If this option is set, support for bzip2 compressed
1698		images is included. If not, only uncompressed and gzip
1699		compressed images are supported.
1700
1701		NOTE: the bzip2 algorithm requires a lot of RAM, so
1702		the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1703		be at least 4MB.
1704
1705		CONFIG_LZMA
1706
1707		If this option is set, support for lzma compressed
1708		images is included.
1709
1710		Note: The LZMA algorithm adds between 2 and 4KB of code and it
1711		requires an amount of dynamic memory that is given by the
1712		formula:
1713
1714			(1846 + 768 << (lc + lp)) * sizeof(uint16)
1715
1716		Where lc and lp stand for, respectively, Literal context bits
1717		and Literal pos bits.
1718
1719		This value is upper-bounded by 14MB in the worst case. Anyway,
1720		for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1721		total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1722		a very small buffer.
1723
1724		Use the lzmainfo tool to determinate the lc and lp values and
1725		then calculate the amount of needed dynamic memory (ensuring
1726		the appropriate CONFIG_SYS_MALLOC_LEN value).
1727
1728		CONFIG_LZO
1729
1730		If this option is set, support for LZO compressed images
1731		is included.
1732
1733- MII/PHY support:
1734		CONFIG_PHY_ADDR
1735
1736		The address of PHY on MII bus.
1737
1738		CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1739
1740		The clock frequency of the MII bus
1741
1742		CONFIG_PHY_GIGE
1743
1744		If this option is set, support for speed/duplex
1745		detection of gigabit PHY is included.
1746
1747		CONFIG_PHY_RESET_DELAY
1748
1749		Some PHY like Intel LXT971A need extra delay after
1750		reset before any MII register access is possible.
1751		For such PHY, set this option to the usec delay
1752		required. (minimum 300usec for LXT971A)
1753
1754		CONFIG_PHY_CMD_DELAY (ppc4xx)
1755
1756		Some PHY like Intel LXT971A need extra delay after
1757		command issued before MII status register can be read
1758
1759- Ethernet address:
1760		CONFIG_ETHADDR
1761		CONFIG_ETH1ADDR
1762		CONFIG_ETH2ADDR
1763		CONFIG_ETH3ADDR
1764		CONFIG_ETH4ADDR
1765		CONFIG_ETH5ADDR
1766
1767		Define a default value for Ethernet address to use
1768		for the respective Ethernet interface, in case this
1769		is not determined automatically.
1770
1771- IP address:
1772		CONFIG_IPADDR
1773
1774		Define a default value for the IP address to use for
1775		the default Ethernet interface, in case this is not
1776		determined through e.g. bootp.
1777		(Environment variable "ipaddr")
1778
1779- Server IP address:
1780		CONFIG_SERVERIP
1781
1782		Defines a default value for the IP address of a TFTP
1783		server to contact when using the "tftboot" command.
1784		(Environment variable "serverip")
1785
1786		CONFIG_KEEP_SERVERADDR
1787
1788		Keeps the server's MAC address, in the env 'serveraddr'
1789		for passing to bootargs (like Linux's netconsole option)
1790
1791- Gateway IP address:
1792		CONFIG_GATEWAYIP
1793
1794		Defines a default value for the IP address of the
1795		default router where packets to other networks are
1796		sent to.
1797		(Environment variable "gatewayip")
1798
1799- Subnet mask:
1800		CONFIG_NETMASK
1801
1802		Defines a default value for the subnet mask (or
1803		routing prefix) which is used to determine if an IP
1804		address belongs to the local subnet or needs to be
1805		forwarded through a router.
1806		(Environment variable "netmask")
1807
1808- Multicast TFTP Mode:
1809		CONFIG_MCAST_TFTP
1810
1811		Defines whether you want to support multicast TFTP as per
1812		rfc-2090; for example to work with atftp.  Lets lots of targets
1813		tftp down the same boot image concurrently.  Note: the Ethernet
1814		driver in use must provide a function: mcast() to join/leave a
1815		multicast group.
1816
1817- BOOTP Recovery Mode:
1818		CONFIG_BOOTP_RANDOM_DELAY
1819
1820		If you have many targets in a network that try to
1821		boot using BOOTP, you may want to avoid that all
1822		systems send out BOOTP requests at precisely the same
1823		moment (which would happen for instance at recovery
1824		from a power failure, when all systems will try to
1825		boot, thus flooding the BOOTP server. Defining
1826		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1827		inserted before sending out BOOTP requests. The
1828		following delays are inserted then:
1829
1830		1st BOOTP request:	delay 0 ... 1 sec
1831		2nd BOOTP request:	delay 0 ... 2 sec
1832		3rd BOOTP request:	delay 0 ... 4 sec
1833		4th and following
1834		BOOTP requests:		delay 0 ... 8 sec
1835
1836- DHCP Advanced Options:
1837		You can fine tune the DHCP functionality by defining
1838		CONFIG_BOOTP_* symbols:
1839
1840		CONFIG_BOOTP_SUBNETMASK
1841		CONFIG_BOOTP_GATEWAY
1842		CONFIG_BOOTP_HOSTNAME
1843		CONFIG_BOOTP_NISDOMAIN
1844		CONFIG_BOOTP_BOOTPATH
1845		CONFIG_BOOTP_BOOTFILESIZE
1846		CONFIG_BOOTP_DNS
1847		CONFIG_BOOTP_DNS2
1848		CONFIG_BOOTP_SEND_HOSTNAME
1849		CONFIG_BOOTP_NTPSERVER
1850		CONFIG_BOOTP_TIMEOFFSET
1851		CONFIG_BOOTP_VENDOREX
1852		CONFIG_BOOTP_MAY_FAIL
1853
1854		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1855		environment variable, not the BOOTP server.
1856
1857		CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1858		after the configured retry count, the call will fail
1859		instead of starting over.  This can be used to fail over
1860		to Link-local IP address configuration if the DHCP server
1861		is not available.
1862
1863		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1864		serverip from a DHCP server, it is possible that more
1865		than one DNS serverip is offered to the client.
1866		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1867		serverip will be stored in the additional environment
1868		variable "dnsip2". The first DNS serverip is always
1869		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1870		is defined.
1871
1872		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1873		to do a dynamic update of a DNS server. To do this, they
1874		need the hostname of the DHCP requester.
1875		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1876		of the "hostname" environment variable is passed as
1877		option 12 to the DHCP server.
1878
1879		CONFIG_BOOTP_DHCP_REQUEST_DELAY
1880
1881		A 32bit value in microseconds for a delay between
1882		receiving a "DHCP Offer" and sending the "DHCP Request".
1883		This fixes a problem with certain DHCP servers that don't
1884		respond 100% of the time to a "DHCP request". E.g. On an
1885		AT91RM9200 processor running at 180MHz, this delay needed
1886		to be *at least* 15,000 usec before a Windows Server 2003
1887		DHCP server would reply 100% of the time. I recommend at
1888		least 50,000 usec to be safe. The alternative is to hope
1889		that one of the retries will be successful but note that
1890		the DHCP timeout and retry process takes a longer than
1891		this delay.
1892
1893 - Link-local IP address negotiation:
1894		Negotiate with other link-local clients on the local network
1895		for an address that doesn't require explicit configuration.
1896		This is especially useful if a DHCP server cannot be guaranteed
1897		to exist in all environments that the device must operate.
1898
1899		See doc/README.link-local for more information.
1900
1901 - CDP Options:
1902		CONFIG_CDP_DEVICE_ID
1903
1904		The device id used in CDP trigger frames.
1905
1906		CONFIG_CDP_DEVICE_ID_PREFIX
1907
1908		A two character string which is prefixed to the MAC address
1909		of the device.
1910
1911		CONFIG_CDP_PORT_ID
1912
1913		A printf format string which contains the ascii name of
1914		the port. Normally is set to "eth%d" which sets
1915		eth0 for the first Ethernet, eth1 for the second etc.
1916
1917		CONFIG_CDP_CAPABILITIES
1918
1919		A 32bit integer which indicates the device capabilities;
1920		0x00000010 for a normal host which does not forwards.
1921
1922		CONFIG_CDP_VERSION
1923
1924		An ascii string containing the version of the software.
1925
1926		CONFIG_CDP_PLATFORM
1927
1928		An ascii string containing the name of the platform.
1929
1930		CONFIG_CDP_TRIGGER
1931
1932		A 32bit integer sent on the trigger.
1933
1934		CONFIG_CDP_POWER_CONSUMPTION
1935
1936		A 16bit integer containing the power consumption of the
1937		device in .1 of milliwatts.
1938
1939		CONFIG_CDP_APPLIANCE_VLAN_TYPE
1940
1941		A byte containing the id of the VLAN.
1942
1943- Status LED:	CONFIG_STATUS_LED
1944
1945		Several configurations allow to display the current
1946		status using a LED. For instance, the LED will blink
1947		fast while running U-Boot code, stop blinking as
1948		soon as a reply to a BOOTP request was received, and
1949		start blinking slow once the Linux kernel is running
1950		(supported by a status LED driver in the Linux
1951		kernel). Defining CONFIG_STATUS_LED enables this
1952		feature in U-Boot.
1953
1954- CAN Support:	CONFIG_CAN_DRIVER
1955
1956		Defining CONFIG_CAN_DRIVER enables CAN driver support
1957		on those systems that support this (optional)
1958		feature, like the TQM8xxL modules.
1959
1960- I2C Support:	CONFIG_SYS_I2C
1961
1962		This enable the NEW i2c subsystem, and will allow you to use
1963		i2c commands at the u-boot command line (as long as you set
1964		CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1965		based realtime clock chips or other i2c devices. See
1966		common/cmd_i2c.c for a description of the command line
1967		interface.
1968
1969		ported i2c driver to the new framework:
1970		- drivers/i2c/soft_i2c.c:
1971		  - activate first bus with CONFIG_SYS_I2C_SOFT define
1972		    CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1973		    for defining speed and slave address
1974		  - activate second bus with I2C_SOFT_DECLARATIONS2 define
1975		    CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1976		    for defining speed and slave address
1977		  - activate third bus with I2C_SOFT_DECLARATIONS3 define
1978		    CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1979		    for defining speed and slave address
1980		  - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1981		    CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1982		    for defining speed and slave address
1983
1984		- drivers/i2c/fsl_i2c.c:
1985		  - activate i2c driver with CONFIG_SYS_I2C_FSL
1986		    define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1987		    offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1988		    CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1989		    bus.
1990		  - If your board supports a second fsl i2c bus, define
1991		    CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1992		    CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1993		    CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1994		    second bus.
1995
1996		- drivers/i2c/tegra_i2c.c:
1997		 - activate this driver with CONFIG_SYS_I2C_TEGRA
1998		 - This driver adds 4 i2c buses with a fix speed from
1999		   100000 and the slave addr 0!
2000
2001		- drivers/i2c/ppc4xx_i2c.c
2002		  - activate this driver with CONFIG_SYS_I2C_PPC4XX
2003		  - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2004		  - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2005
2006		- drivers/i2c/i2c_mxc.c
2007		  - activate this driver with CONFIG_SYS_I2C_MXC
2008		  - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2009		  - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2010		  - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2011		  - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2012		  - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2013		  - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2014		If thoses defines are not set, default value is 100000
2015		for speed, and 0 for slave.
2016
2017		additional defines:
2018
2019		CONFIG_SYS_NUM_I2C_BUSES
2020		Hold the number of i2c busses you want to use. If you
2021		don't use/have i2c muxes on your i2c bus, this
2022		is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2023		omit this define.
2024
2025		CONFIG_SYS_I2C_DIRECT_BUS
2026		define this, if you don't use i2c muxes on your hardware.
2027		if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2028		omit this define.
2029
2030		CONFIG_SYS_I2C_MAX_HOPS
2031		define how many muxes are maximal consecutively connected
2032		on one i2c bus. If you not use i2c muxes, omit this
2033		define.
2034
2035		CONFIG_SYS_I2C_BUSES
2036		hold a list of busses you want to use, only used if
2037		CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2038		a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2039		CONFIG_SYS_NUM_I2C_BUSES = 9:
2040
2041		 CONFIG_SYS_I2C_BUSES	{{0, {I2C_NULL_HOP}}, \
2042					{0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2043					{0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2044					{0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2045					{0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2046					{0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2047					{1, {I2C_NULL_HOP}}, \
2048					{1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2049					{1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2050					}
2051
2052		which defines
2053			bus 0 on adapter 0 without a mux
2054			bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2055			bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2056			bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2057			bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2058			bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2059			bus 6 on adapter 1 without a mux
2060			bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2061			bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2062
2063		If you do not have i2c muxes on your board, omit this define.
2064
2065- Legacy I2C Support:	CONFIG_HARD_I2C
2066
2067		NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2068		provides the following compelling advantages:
2069
2070		- more than one i2c adapter is usable
2071		- approved multibus support
2072		- better i2c mux support
2073
2074		** Please consider updating your I2C driver now. **
2075
2076		These enable legacy I2C serial bus commands. Defining
2077		CONFIG_HARD_I2C will include the appropriate I2C driver
2078		for the selected CPU.
2079
2080		This will allow you to use i2c commands at the u-boot
2081		command line (as long as you set CONFIG_CMD_I2C in
2082		CONFIG_COMMANDS) and communicate with i2c based realtime
2083		clock chips. See common/cmd_i2c.c for a description of the
2084		command line interface.
2085
2086		CONFIG_HARD_I2C selects a hardware I2C controller.
2087
2088		There are several other quantities that must also be
2089		defined when you define CONFIG_HARD_I2C.
2090
2091		In both cases you will need to define CONFIG_SYS_I2C_SPEED
2092		to be the frequency (in Hz) at which you wish your i2c bus
2093		to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2094		the CPU's i2c node address).
2095
2096		Now, the u-boot i2c code for the mpc8xx
2097		(arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2098		and so its address should therefore be cleared to 0 (See,
2099		eg, MPC823e User's Manual p.16-473). So, set
2100		CONFIG_SYS_I2C_SLAVE to 0.
2101
2102		CONFIG_SYS_I2C_INIT_MPC5XXX
2103
2104		When a board is reset during an i2c bus transfer
2105		chips might think that the current transfer is still
2106		in progress.  Reset the slave devices by sending start
2107		commands until the slave device responds.
2108
2109		That's all that's required for CONFIG_HARD_I2C.
2110
2111		If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2112		then the following macros need to be defined (examples are
2113		from include/configs/lwmon.h):
2114
2115		I2C_INIT
2116
2117		(Optional). Any commands necessary to enable the I2C
2118		controller or configure ports.
2119
2120		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)
2121
2122		I2C_PORT
2123
2124		(Only for MPC8260 CPU). The I/O port to use (the code
2125		assumes both bits are on the same port). Valid values
2126		are 0..3 for ports A..D.
2127
2128		I2C_ACTIVE
2129
2130		The code necessary to make the I2C data line active
2131		(driven).  If the data line is open collector, this
2132		define can be null.
2133
2134		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
2135
2136		I2C_TRISTATE
2137
2138		The code necessary to make the I2C data line tri-stated
2139		(inactive).  If the data line is open collector, this
2140		define can be null.
2141
2142		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2143
2144		I2C_READ
2145
2146		Code that returns true if the I2C data line is high,
2147		false if it is low.
2148
2149		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2150
2151		I2C_SDA(bit)
2152
2153		If <bit> is true, sets the I2C data line high. If it
2154		is false, it clears it (low).
2155
2156		eg: #define I2C_SDA(bit) \
2157			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
2158			else	immr->im_cpm.cp_pbdat &= ~PB_SDA
2159
2160		I2C_SCL(bit)
2161
2162		If <bit> is true, sets the I2C clock line high. If it
2163		is false, it clears it (low).
2164
2165		eg: #define I2C_SCL(bit) \
2166			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
2167			else	immr->im_cpm.cp_pbdat &= ~PB_SCL
2168
2169		I2C_DELAY
2170
2171		This delay is invoked four times per clock cycle so this
2172		controls the rate of data transfer.  The data rate thus
2173		is 1 / (I2C_DELAY * 4). Often defined to be something
2174		like:
2175
2176		#define I2C_DELAY  udelay(2)
2177
2178		CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2179
2180		If your arch supports the generic GPIO framework (asm/gpio.h),
2181		then you may alternatively define the two GPIOs that are to be
2182		used as SCL / SDA.  Any of the previous I2C_xxx macros will
2183		have GPIO-based defaults assigned to them as appropriate.
2184
2185		You should define these to the GPIO value as given directly to
2186		the generic GPIO functions.
2187
2188		CONFIG_SYS_I2C_INIT_BOARD
2189
2190		When a board is reset during an i2c bus transfer
2191		chips might think that the current transfer is still
2192		in progress. On some boards it is possible to access
2193		the i2c SCLK line directly, either by using the
2194		processor pin as a GPIO or by having a second pin
2195		connected to the bus. If this option is defined a
2196		custom i2c_init_board() routine in boards/xxx/board.c
2197		is run early in the boot sequence.
2198
2199		CONFIG_SYS_I2C_BOARD_LATE_INIT
2200
2201		An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2202		defined a custom i2c_board_late_init() routine in
2203		boards/xxx/board.c is run AFTER the operations in i2c_init()
2204		is completed. This callpoint can be used to unreset i2c bus
2205		using CPU i2c controller register accesses for CPUs whose i2c
2206		controller provide such a method. It is called at the end of
2207		i2c_init() to allow i2c_init operations to setup the i2c bus
2208		controller on the CPU (e.g. setting bus speed & slave address).
2209
2210		CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2211
2212		This option enables configuration of bi_iic_fast[] flags
2213		in u-boot bd_info structure based on u-boot environment
2214		variable "i2cfast". (see also i2cfast)
2215
2216		CONFIG_I2C_MULTI_BUS
2217
2218		This option allows the use of multiple I2C buses, each of which
2219		must have a controller.	 At any point in time, only one bus is
2220		active.	 To switch to a different bus, use the 'i2c dev' command.
2221		Note that bus numbering is zero-based.
2222
2223		CONFIG_SYS_I2C_NOPROBES
2224
2225		This option specifies a list of I2C devices that will be skipped
2226		when the 'i2c probe' command is issued.	 If CONFIG_I2C_MULTI_BUS
2227		is set, specify a list of bus-device pairs.  Otherwise, specify
2228		a 1D array of device addresses
2229
2230		e.g.
2231			#undef	CONFIG_I2C_MULTI_BUS
2232			#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2233
2234		will skip addresses 0x50 and 0x68 on a board with one I2C bus
2235
2236			#define CONFIG_I2C_MULTI_BUS
2237			#define CONFIG_SYS_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
2238
2239		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2240
2241		CONFIG_SYS_SPD_BUS_NUM
2242
2243		If defined, then this indicates the I2C bus number for DDR SPD.
2244		If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2245
2246		CONFIG_SYS_RTC_BUS_NUM
2247
2248		If defined, then this indicates the I2C bus number for the RTC.
2249		If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2250
2251		CONFIG_SYS_DTT_BUS_NUM
2252
2253		If defined, then this indicates the I2C bus number for the DTT.
2254		If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2255
2256		CONFIG_SYS_I2C_DTT_ADDR:
2257
2258		If defined, specifies the I2C address of the DTT device.
2259		If not defined, then U-Boot uses predefined value for
2260		specified DTT device.
2261
2262		CONFIG_SOFT_I2C_READ_REPEATED_START
2263
2264		defining this will force the i2c_read() function in
2265		the soft_i2c driver to perform an I2C repeated start
2266		between writing the address pointer and reading the
2267		data.  If this define is omitted the default behaviour
2268		of doing a stop-start sequence will be used.  Most I2C
2269		devices can use either method, but some require one or
2270		the other.
2271
2272- SPI Support:	CONFIG_SPI
2273
2274		Enables SPI driver (so far only tested with
2275		SPI EEPROM, also an instance works with Crystal A/D and
2276		D/As on the SACSng board)
2277
2278		CONFIG_SH_SPI
2279
2280		Enables the driver for SPI controller on SuperH. Currently
2281		only SH7757 is supported.
2282
2283		CONFIG_SPI_X
2284
2285		Enables extended (16-bit) SPI EEPROM addressing.
2286		(symmetrical to CONFIG_I2C_X)
2287
2288		CONFIG_SOFT_SPI
2289
2290		Enables a software (bit-bang) SPI driver rather than
2291		using hardware support. This is a general purpose
2292		driver that only requires three general I/O port pins
2293		(two outputs, one input) to function. If this is
2294		defined, the board configuration must define several
2295		SPI configuration items (port pins to use, etc). For
2296		an example, see include/configs/sacsng.h.
2297
2298		CONFIG_HARD_SPI
2299
2300		Enables a hardware SPI driver for general-purpose reads
2301		and writes.  As with CONFIG_SOFT_SPI, the board configuration
2302		must define a list of chip-select function pointers.
2303		Currently supported on some MPC8xxx processors.	 For an
2304		example, see include/configs/mpc8349emds.h.
2305
2306		CONFIG_MXC_SPI
2307
2308		Enables the driver for the SPI controllers on i.MX and MXC
2309		SoCs. Currently i.MX31/35/51 are supported.
2310
2311- FPGA Support: CONFIG_FPGA
2312
2313		Enables FPGA subsystem.
2314
2315		CONFIG_FPGA_<vendor>
2316
2317		Enables support for specific chip vendors.
2318		(ALTERA, XILINX)
2319
2320		CONFIG_FPGA_<family>
2321
2322		Enables support for FPGA family.
2323		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2324
2325		CONFIG_FPGA_COUNT
2326
2327		Specify the number of FPGA devices to support.
2328
2329		CONFIG_SYS_FPGA_PROG_FEEDBACK
2330
2331		Enable printing of hash marks during FPGA configuration.
2332
2333		CONFIG_SYS_FPGA_CHECK_BUSY
2334
2335		Enable checks on FPGA configuration interface busy
2336		status by the configuration function. This option
2337		will require a board or device specific function to
2338		be written.
2339
2340		CONFIG_FPGA_DELAY
2341
2342		If defined, a function that provides delays in the FPGA
2343		configuration driver.
2344
2345		CONFIG_SYS_FPGA_CHECK_CTRLC
2346		Allow Control-C to interrupt FPGA configuration
2347
2348		CONFIG_SYS_FPGA_CHECK_ERROR
2349
2350		Check for configuration errors during FPGA bitfile
2351		loading. For example, abort during Virtex II
2352		configuration if the INIT_B line goes low (which
2353		indicated a CRC error).
2354
2355		CONFIG_SYS_FPGA_WAIT_INIT
2356
2357		Maximum time to wait for the INIT_B line to deassert
2358		after PROB_B has been deasserted during a Virtex II
2359		FPGA configuration sequence. The default time is 500
2360		ms.
2361
2362		CONFIG_SYS_FPGA_WAIT_BUSY
2363
2364		Maximum time to wait for BUSY to deassert during
2365		Virtex II FPGA configuration. The default is 5 ms.
2366
2367		CONFIG_SYS_FPGA_WAIT_CONFIG
2368
2369		Time to wait after FPGA configuration. The default is
2370		200 ms.
2371
2372- Configuration Management:
2373		CONFIG_IDENT_STRING
2374
2375		If defined, this string will be added to the U-Boot
2376		version information (U_BOOT_VERSION)
2377
2378- Vendor Parameter Protection:
2379
2380		U-Boot considers the values of the environment
2381		variables "serial#" (Board Serial Number) and
2382		"ethaddr" (Ethernet Address) to be parameters that
2383		are set once by the board vendor / manufacturer, and
2384		protects these variables from casual modification by
2385		the user. Once set, these variables are read-only,
2386		and write or delete attempts are rejected. You can
2387		change this behaviour:
2388
2389		If CONFIG_ENV_OVERWRITE is #defined in your config
2390		file, the write protection for vendor parameters is
2391		completely disabled. Anybody can change or delete
2392		these parameters.
2393
2394		Alternatively, if you #define _both_ CONFIG_ETHADDR
2395		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2396		Ethernet address is installed in the environment,
2397		which can be changed exactly ONCE by the user. [The
2398		serial# is unaffected by this, i. e. it remains
2399		read-only.]
2400
2401		The same can be accomplished in a more flexible way
2402		for any variable by configuring the type of access
2403		to allow for those variables in the ".flags" variable
2404		or define CONFIG_ENV_FLAGS_LIST_STATIC.
2405
2406- Protected RAM:
2407		CONFIG_PRAM
2408
2409		Define this variable to enable the reservation of
2410		"protected RAM", i. e. RAM which is not overwritten
2411		by U-Boot. Define CONFIG_PRAM to hold the number of
2412		kB you want to reserve for pRAM. You can overwrite
2413		this default value by defining an environment
2414		variable "pram" to the number of kB you want to
2415		reserve. Note that the board info structure will
2416		still show the full amount of RAM. If pRAM is
2417		reserved, a new environment variable "mem" will
2418		automatically be defined to hold the amount of
2419		remaining RAM in a form that can be passed as boot
2420		argument to Linux, for instance like that:
2421
2422			setenv bootargs ... mem=\${mem}
2423			saveenv
2424
2425		This way you can tell Linux not to use this memory,
2426		either, which results in a memory region that will
2427		not be affected by reboots.
2428
2429		*WARNING* If your board configuration uses automatic
2430		detection of the RAM size, you must make sure that
2431		this memory test is non-destructive. So far, the
2432		following board configurations are known to be
2433		"pRAM-clean":
2434
2435			IVMS8, IVML24, SPD8xx, TQM8xxL,
2436			HERMES, IP860, RPXlite, LWMON,
2437			FLAGADM, TQM8260
2438
2439- Access to physical memory region (> 4GB)
2440		Some basic support is provided for operations on memory not
2441		normally accessible to U-Boot - e.g. some architectures
2442		support access to more than 4GB of memory on 32-bit
2443		machines using physical address extension or similar.
2444		Define CONFIG_PHYSMEM to access this basic support, which
2445		currently only supports clearing the memory.
2446
2447- Error Recovery:
2448		CONFIG_PANIC_HANG
2449
2450		Define this variable to stop the system in case of a
2451		fatal error, so that you have to reset it manually.
2452		This is probably NOT a good idea for an embedded
2453		system where you want the system to reboot
2454		automatically as fast as possible, but it may be
2455		useful during development since you can try to debug
2456		the conditions that lead to the situation.
2457
2458		CONFIG_NET_RETRY_COUNT
2459
2460		This variable defines the number of retries for
2461		network operations like ARP, RARP, TFTP, or BOOTP
2462		before giving up the operation. If not defined, a
2463		default value of 5 is used.
2464
2465		CONFIG_ARP_TIMEOUT
2466
2467		Timeout waiting for an ARP reply in milliseconds.
2468
2469		CONFIG_NFS_TIMEOUT
2470
2471		Timeout in milliseconds used in NFS protocol.
2472		If you encounter "ERROR: Cannot umount" in nfs command,
2473		try longer timeout such as
2474		#define CONFIG_NFS_TIMEOUT 10000UL
2475
2476- Command Interpreter:
2477		CONFIG_AUTO_COMPLETE
2478
2479		Enable auto completion of commands using TAB.
2480
2481		Note that this feature has NOT been implemented yet
2482		for the "hush" shell.
2483
2484
2485		CONFIG_SYS_HUSH_PARSER
2486
2487		Define this variable to enable the "hush" shell (from
2488		Busybox) as command line interpreter, thus enabling
2489		powerful command line syntax like
2490		if...then...else...fi conditionals or `&&' and '||'
2491		constructs ("shell scripts").
2492
2493		If undefined, you get the old, much simpler behaviour
2494		with a somewhat smaller memory footprint.
2495
2496
2497		CONFIG_SYS_PROMPT_HUSH_PS2
2498
2499		This defines the secondary prompt string, which is
2500		printed when the command interpreter needs more input
2501		to complete a command. Usually "> ".
2502
2503	Note:
2504
2505		In the current implementation, the local variables
2506		space and global environment variables space are
2507		separated. Local variables are those you define by
2508		simply typing `name=value'. To access a local
2509		variable later on, you have write `$name' or
2510		`${name}'; to execute the contents of a variable
2511		directly type `$name' at the command prompt.
2512
2513		Global environment variables are those you use
2514		setenv/printenv to work with. To run a command stored
2515		in such a variable, you need to use the run command,
2516		and you must not use the '$' sign to access them.
2517
2518		To store commands and special characters in a
2519		variable, please use double quotation marks
2520		surrounding the whole text of the variable, instead
2521		of the backslashes before semicolons and special
2522		symbols.
2523
2524- Commandline Editing and History:
2525		CONFIG_CMDLINE_EDITING
2526
2527		Enable editing and History functions for interactive
2528		commandline input operations
2529
2530- Default Environment:
2531		CONFIG_EXTRA_ENV_SETTINGS
2532
2533		Define this to contain any number of null terminated
2534		strings (variable = value pairs) that will be part of
2535		the default environment compiled into the boot image.
2536
2537		For example, place something like this in your
2538		board's config file:
2539
2540		#define CONFIG_EXTRA_ENV_SETTINGS \
2541			"myvar1=value1\0" \
2542			"myvar2=value2\0"
2543
2544		Warning: This method is based on knowledge about the
2545		internal format how the environment is stored by the
2546		U-Boot code. This is NOT an official, exported
2547		interface! Although it is unlikely that this format
2548		will change soon, there is no guarantee either.
2549		You better know what you are doing here.
2550
2551		Note: overly (ab)use of the default environment is
2552		discouraged. Make sure to check other ways to preset
2553		the environment like the "source" command or the
2554		boot command first.
2555
2556		CONFIG_ENV_VARS_UBOOT_CONFIG
2557
2558		Define this in order to add variables describing the
2559		U-Boot build configuration to the default environment.
2560		These will be named arch, cpu, board, vendor, and soc.
2561
2562		Enabling this option will cause the following to be defined:
2563
2564		- CONFIG_SYS_ARCH
2565		- CONFIG_SYS_CPU
2566		- CONFIG_SYS_BOARD
2567		- CONFIG_SYS_VENDOR
2568		- CONFIG_SYS_SOC
2569
2570		CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2571
2572		Define this in order to add variables describing certain
2573		run-time determined information about the hardware to the
2574		environment.  These will be named board_name, board_rev.
2575
2576		CONFIG_DELAY_ENVIRONMENT
2577
2578		Normally the environment is loaded when the board is
2579		intialised so that it is available to U-Boot. This inhibits
2580		that so that the environment is not available until
2581		explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2582		this is instead controlled by the value of
2583		/config/load-environment.
2584
2585- DataFlash Support:
2586		CONFIG_HAS_DATAFLASH
2587
2588		Defining this option enables DataFlash features and
2589		allows to read/write in Dataflash via the standard
2590		commands cp, md...
2591
2592- Serial Flash support
2593		CONFIG_CMD_SF
2594
2595		Defining this option enables SPI flash commands
2596		'sf probe/read/write/erase/update'.
2597
2598		Usage requires an initial 'probe' to define the serial
2599		flash parameters, followed by read/write/erase/update
2600		commands.
2601
2602		The following defaults may be provided by the platform
2603		to handle the common case when only a single serial
2604		flash is present on the system.
2605
2606		CONFIG_SF_DEFAULT_BUS		Bus identifier
2607		CONFIG_SF_DEFAULT_CS		Chip-select
2608		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
2609		CONFIG_SF_DEFAULT_SPEED		in Hz
2610
2611		CONFIG_CMD_SF_TEST
2612
2613		Define this option to include a destructive SPI flash
2614		test ('sf test').
2615
2616		CONFIG_SPI_FLASH_BAR		Ban/Extended Addr Reg
2617
2618		Define this option to use the Bank addr/Extended addr
2619		support on SPI flashes which has size > 16Mbytes.
2620
2621- SystemACE Support:
2622		CONFIG_SYSTEMACE
2623
2624		Adding this option adds support for Xilinx SystemACE
2625		chips attached via some sort of local bus. The address
2626		of the chip must also be defined in the
2627		CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2628
2629		#define CONFIG_SYSTEMACE
2630		#define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2631
2632		When SystemACE support is added, the "ace" device type
2633		becomes available to the fat commands, i.e. fatls.
2634
2635- TFTP Fixed UDP Port:
2636		CONFIG_TFTP_PORT
2637
2638		If this is defined, the environment variable tftpsrcp
2639		is used to supply the TFTP UDP source port value.
2640		If tftpsrcp isn't defined, the normal pseudo-random port
2641		number generator is used.
2642
2643		Also, the environment variable tftpdstp is used to supply
2644		the TFTP UDP destination port value.  If tftpdstp isn't
2645		defined, the normal port 69 is used.
2646
2647		The purpose for tftpsrcp is to allow a TFTP server to
2648		blindly start the TFTP transfer using the pre-configured
2649		target IP address and UDP port. This has the effect of
2650		"punching through" the (Windows XP) firewall, allowing
2651		the remainder of the TFTP transfer to proceed normally.
2652		A better solution is to properly configure the firewall,
2653		but sometimes that is not allowed.
2654
2655- Hashing support:
2656		CONFIG_CMD_HASH
2657
2658		This enables a generic 'hash' command which can produce
2659		hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2660
2661		CONFIG_HASH_VERIFY
2662
2663		Enable the hash verify command (hash -v). This adds to code
2664		size a little.
2665
2666		CONFIG_SHA1 - support SHA1 hashing
2667		CONFIG_SHA256 - support SHA256 hashing
2668
2669		Note: There is also a sha1sum command, which should perhaps
2670		be deprecated in favour of 'hash sha1'.
2671
2672- Freescale i.MX specific commands:
2673		CONFIG_CMD_HDMIDETECT
2674		This enables 'hdmidet' command which returns true if an
2675		HDMI monitor is detected.  This command is i.MX 6 specific.
2676
2677		CONFIG_CMD_BMODE
2678		This enables the 'bmode' (bootmode) command for forcing
2679		a boot from specific media.
2680
2681		This is useful for forcing the ROM's usb downloader to
2682		activate upon a watchdog reset which is nice when iterating
2683		on U-Boot.  Using the reset button or running bmode normal
2684		will set it back to normal.  This command currently
2685		supports i.MX53 and i.MX6.
2686
2687- Signing support:
2688		CONFIG_RSA
2689
2690		This enables the RSA algorithm used for FIT image verification
2691		in U-Boot. See doc/uImage/signature for more information.
2692
2693		The signing part is build into mkimage regardless of this
2694		option.
2695
2696
2697- Show boot progress:
2698		CONFIG_SHOW_BOOT_PROGRESS
2699
2700		Defining this option allows to add some board-
2701		specific code (calling a user-provided function
2702		"show_boot_progress(int)") that enables you to show
2703		the system's boot progress on some display (for
2704		example, some LED's) on your board. At the moment,
2705		the following checkpoints are implemented:
2706
2707- Detailed boot stage timing
2708		CONFIG_BOOTSTAGE
2709		Define this option to get detailed timing of each stage
2710		of the boot process.
2711
2712		CONFIG_BOOTSTAGE_USER_COUNT
2713		This is the number of available user bootstage records.
2714		Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2715		a new ID will be allocated from this stash. If you exceed
2716		the limit, recording will stop.
2717
2718		CONFIG_BOOTSTAGE_REPORT
2719		Define this to print a report before boot, similar to this:
2720
2721		Timer summary in microseconds:
2722		       Mark    Elapsed  Stage
2723			  0          0  reset
2724		  3,575,678  3,575,678  board_init_f start
2725		  3,575,695         17  arch_cpu_init A9
2726		  3,575,777         82  arch_cpu_init done
2727		  3,659,598     83,821  board_init_r start
2728		  3,910,375    250,777  main_loop
2729		 29,916,167 26,005,792  bootm_start
2730		 30,361,327    445,160  start_kernel
2731
2732		CONFIG_CMD_BOOTSTAGE
2733		Add a 'bootstage' command which supports printing a report
2734		and un/stashing of bootstage data.
2735
2736		CONFIG_BOOTSTAGE_FDT
2737		Stash the bootstage information in the FDT. A root 'bootstage'
2738		node is created with each bootstage id as a child. Each child
2739		has a 'name' property and either 'mark' containing the
2740		mark time in microsecond, or 'accum' containing the
2741		accumulated time for that bootstage id in microseconds.
2742		For example:
2743
2744		bootstage {
2745			154 {
2746				name = "board_init_f";
2747				mark = <3575678>;
2748			};
2749			170 {
2750				name = "lcd";
2751				accum = <33482>;
2752			};
2753		};
2754
2755		Code in the Linux kernel can find this in /proc/devicetree.
2756
2757Legacy uImage format:
2758
2759  Arg	Where			When
2760    1	common/cmd_bootm.c	before attempting to boot an image
2761   -1	common/cmd_bootm.c	Image header has bad	 magic number
2762    2	common/cmd_bootm.c	Image header has correct magic number
2763   -2	common/cmd_bootm.c	Image header has bad	 checksum
2764    3	common/cmd_bootm.c	Image header has correct checksum
2765   -3	common/cmd_bootm.c	Image data   has bad	 checksum
2766    4	common/cmd_bootm.c	Image data   has correct checksum
2767   -4	common/cmd_bootm.c	Image is for unsupported architecture
2768    5	common/cmd_bootm.c	Architecture check OK
2769   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
2770    6	common/cmd_bootm.c	Image Type check OK
2771   -6	common/cmd_bootm.c	gunzip uncompression error
2772   -7	common/cmd_bootm.c	Unimplemented compression type
2773    7	common/cmd_bootm.c	Uncompression OK
2774    8	common/cmd_bootm.c	No uncompress/copy overwrite error
2775   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
2776
2777    9	common/image.c		Start initial ramdisk verification
2778  -10	common/image.c		Ramdisk header has bad	   magic number
2779  -11	common/image.c		Ramdisk header has bad	   checksum
2780   10	common/image.c		Ramdisk header is OK
2781  -12	common/image.c		Ramdisk data   has bad	   checksum
2782   11	common/image.c		Ramdisk data   has correct checksum
2783   12	common/image.c		Ramdisk verification complete, start loading
2784  -13	common/image.c		Wrong Image Type (not PPC Linux ramdisk)
2785   13	common/image.c		Start multifile image verification
2786   14	common/image.c		No initial ramdisk, no multifile, continue.
2787
2788   15	arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2789
2790  -30	arch/powerpc/lib/board.c	Fatal error, hang the system
2791  -31	post/post.c		POST test failed, detected by post_output_backlog()
2792  -32	post/post.c		POST test failed, detected by post_run_single()
2793
2794   34	common/cmd_doc.c	before loading a Image from a DOC device
2795  -35	common/cmd_doc.c	Bad usage of "doc" command
2796   35	common/cmd_doc.c	correct usage of "doc" command
2797  -36	common/cmd_doc.c	No boot device
2798   36	common/cmd_doc.c	correct boot device
2799  -37	common/cmd_doc.c	Unknown Chip ID on boot device
2800   37	common/cmd_doc.c	correct chip ID found, device available
2801  -38	common/cmd_doc.c	Read Error on boot device
2802   38	common/cmd_doc.c	reading Image header from DOC device OK
2803  -39	common/cmd_doc.c	Image header has bad magic number
2804   39	common/cmd_doc.c	Image header has correct magic number
2805  -40	common/cmd_doc.c	Error reading Image from DOC device
2806   40	common/cmd_doc.c	Image header has correct magic number
2807   41	common/cmd_ide.c	before loading a Image from a IDE device
2808  -42	common/cmd_ide.c	Bad usage of "ide" command
2809   42	common/cmd_ide.c	correct usage of "ide" command
2810  -43	common/cmd_ide.c	No boot device
2811   43	common/cmd_ide.c	boot device found
2812  -44	common/cmd_ide.c	Device not available
2813   44	common/cmd_ide.c	Device available
2814  -45	common/cmd_ide.c	wrong partition selected
2815   45	common/cmd_ide.c	partition selected
2816  -46	common/cmd_ide.c	Unknown partition table
2817   46	common/cmd_ide.c	valid partition table found
2818  -47	common/cmd_ide.c	Invalid partition type
2819   47	common/cmd_ide.c	correct partition type
2820  -48	common/cmd_ide.c	Error reading Image Header on boot device
2821   48	common/cmd_ide.c	reading Image Header from IDE device OK
2822  -49	common/cmd_ide.c	Image header has bad magic number
2823   49	common/cmd_ide.c	Image header has correct magic number
2824  -50	common/cmd_ide.c	Image header has bad	 checksum
2825   50	common/cmd_ide.c	Image header has correct checksum
2826  -51	common/cmd_ide.c	Error reading Image from IDE device
2827   51	common/cmd_ide.c	reading Image from IDE device OK
2828   52	common/cmd_nand.c	before loading a Image from a NAND device
2829  -53	common/cmd_nand.c	Bad usage of "nand" command
2830   53	common/cmd_nand.c	correct usage of "nand" command
2831  -54	common/cmd_nand.c	No boot device
2832   54	common/cmd_nand.c	boot device found
2833  -55	common/cmd_nand.c	Unknown Chip ID on boot device
2834   55	common/cmd_nand.c	correct chip ID found, device available
2835  -56	common/cmd_nand.c	Error reading Image Header on boot device
2836   56	common/cmd_nand.c	reading Image Header from NAND device OK
2837  -57	common/cmd_nand.c	Image header has bad magic number
2838   57	common/cmd_nand.c	Image header has correct magic number
2839  -58	common/cmd_nand.c	Error reading Image from NAND device
2840   58	common/cmd_nand.c	reading Image from NAND device OK
2841
2842  -60	common/env_common.c	Environment has a bad CRC, using default
2843
2844   64	net/eth.c		starting with Ethernet configuration.
2845  -64	net/eth.c		no Ethernet found.
2846   65	net/eth.c		Ethernet found.
2847
2848  -80	common/cmd_net.c	usage wrong
2849   80	common/cmd_net.c	before calling NetLoop()
2850  -81	common/cmd_net.c	some error in NetLoop() occurred
2851   81	common/cmd_net.c	NetLoop() back without error
2852  -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
2853   82	common/cmd_net.c	trying automatic boot
2854   83	common/cmd_net.c	running "source" command
2855  -83	common/cmd_net.c	some error in automatic boot or "source" command
2856   84	common/cmd_net.c	end without errors
2857
2858FIT uImage format:
2859
2860  Arg	Where			When
2861  100	common/cmd_bootm.c	Kernel FIT Image has correct format
2862 -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
2863  101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
2864 -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
2865  102	common/cmd_bootm.c	Kernel unit name specified
2866 -103	common/cmd_bootm.c	Can't get kernel subimage node offset
2867  103	common/cmd_bootm.c	Found configuration node
2868  104	common/cmd_bootm.c	Got kernel subimage node offset
2869 -104	common/cmd_bootm.c	Kernel subimage hash verification failed
2870  105	common/cmd_bootm.c	Kernel subimage hash verification OK
2871 -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
2872  106	common/cmd_bootm.c	Architecture check OK
2873 -106	common/cmd_bootm.c	Kernel subimage has wrong type
2874  107	common/cmd_bootm.c	Kernel subimage type OK
2875 -107	common/cmd_bootm.c	Can't get kernel subimage data/size
2876  108	common/cmd_bootm.c	Got kernel subimage data/size
2877 -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
2878 -109	common/cmd_bootm.c	Can't get kernel subimage type
2879 -110	common/cmd_bootm.c	Can't get kernel subimage comp
2880 -111	common/cmd_bootm.c	Can't get kernel subimage os
2881 -112	common/cmd_bootm.c	Can't get kernel subimage load address
2882 -113	common/cmd_bootm.c	Image uncompress/copy overwrite error
2883
2884  120	common/image.c		Start initial ramdisk verification
2885 -120	common/image.c		Ramdisk FIT image has incorrect format
2886  121	common/image.c		Ramdisk FIT image has correct format
2887  122	common/image.c		No ramdisk subimage unit name, using configuration
2888 -122	common/image.c		Can't get configuration for ramdisk subimage
2889  123	common/image.c		Ramdisk unit name specified
2890 -124	common/image.c		Can't get ramdisk subimage node offset
2891  125	common/image.c		Got ramdisk subimage node offset
2892 -125	common/image.c		Ramdisk subimage hash verification failed
2893  126	common/image.c		Ramdisk subimage hash verification OK
2894 -126	common/image.c		Ramdisk subimage for unsupported architecture
2895  127	common/image.c		Architecture check OK
2896 -127	common/image.c		Can't get ramdisk subimage data/size
2897  128	common/image.c		Got ramdisk subimage data/size
2898  129	common/image.c		Can't get ramdisk load address
2899 -129	common/image.c		Got ramdisk load address
2900
2901 -130	common/cmd_doc.c	Incorrect FIT image format
2902  131	common/cmd_doc.c	FIT image format OK
2903
2904 -140	common/cmd_ide.c	Incorrect FIT image format
2905  141	common/cmd_ide.c	FIT image format OK
2906
2907 -150	common/cmd_nand.c	Incorrect FIT image format
2908  151	common/cmd_nand.c	FIT image format OK
2909
2910- FIT image support:
2911		CONFIG_FIT
2912		Enable support for the FIT uImage format.
2913
2914		CONFIG_FIT_BEST_MATCH
2915		When no configuration is explicitly selected, default to the
2916		one whose fdt's compatibility field best matches that of
2917		U-Boot itself. A match is considered "best" if it matches the
2918		most specific compatibility entry of U-Boot's fdt's root node.
2919		The order of entries in the configuration's fdt is ignored.
2920
2921		CONFIG_FIT_SIGNATURE
2922		This option enables signature verification of FIT uImages,
2923		using a hash signed and verified using RSA. See
2924		doc/uImage.FIT/signature.txt for more details.
2925
2926- Standalone program support:
2927		CONFIG_STANDALONE_LOAD_ADDR
2928
2929		This option defines a board specific value for the
2930		address where standalone program gets loaded, thus
2931		overwriting the architecture dependent default
2932		settings.
2933
2934- Frame Buffer Address:
2935		CONFIG_FB_ADDR
2936
2937		Define CONFIG_FB_ADDR if you want to use specific
2938		address for frame buffer.  This is typically the case
2939		when using a graphics controller has separate video
2940		memory.  U-Boot will then place the frame buffer at
2941		the given address instead of dynamically reserving it
2942		in system RAM by calling lcd_setmem(), which grabs
2943		the memory for the frame buffer depending on the
2944		configured panel size.
2945
2946		Please see board_init_f function.
2947
2948- Automatic software updates via TFTP server
2949		CONFIG_UPDATE_TFTP
2950		CONFIG_UPDATE_TFTP_CNT_MAX
2951		CONFIG_UPDATE_TFTP_MSEC_MAX
2952
2953		These options enable and control the auto-update feature;
2954		for a more detailed description refer to doc/README.update.
2955
2956- MTD Support (mtdparts command, UBI support)
2957		CONFIG_MTD_DEVICE
2958
2959		Adds the MTD device infrastructure from the Linux kernel.
2960		Needed for mtdparts command support.
2961
2962		CONFIG_MTD_PARTITIONS
2963
2964		Adds the MTD partitioning infrastructure from the Linux
2965		kernel. Needed for UBI support.
2966
2967- UBI support
2968		CONFIG_CMD_UBI
2969
2970		Adds commands for interacting with MTD partitions formatted
2971		with the UBI flash translation layer
2972
2973		Requires also defining CONFIG_RBTREE
2974
2975		CONFIG_UBI_SILENCE_MSG
2976
2977		Make the verbose messages from UBI stop printing.  This leaves
2978		warnings and errors enabled.
2979
2980- UBIFS support
2981		CONFIG_CMD_UBIFS
2982
2983		Adds commands for interacting with UBI volumes formatted as
2984		UBIFS.  UBIFS is read-only in u-boot.
2985
2986		Requires UBI support as well as CONFIG_LZO
2987
2988		CONFIG_UBIFS_SILENCE_MSG
2989
2990		Make the verbose messages from UBIFS stop printing.  This leaves
2991		warnings and errors enabled.
2992
2993- SPL framework
2994		CONFIG_SPL
2995		Enable building of SPL globally.
2996
2997		CONFIG_SPL_LDSCRIPT
2998		LDSCRIPT for linking the SPL binary.
2999
3000		CONFIG_SPL_MAX_FOOTPRINT
3001		Maximum size in memory allocated to the SPL, BSS included.
3002		When defined, the linker checks that the actual memory
3003		used by SPL from _start to __bss_end does not exceed it.
3004		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3005		must not be both defined at the same time.
3006
3007		CONFIG_SPL_MAX_SIZE
3008		Maximum size of the SPL image (text, data, rodata, and
3009		linker lists sections), BSS excluded.
3010		When defined, the linker checks that the actual size does
3011		not exceed it.
3012
3013		CONFIG_SPL_TEXT_BASE
3014		TEXT_BASE for linking the SPL binary.
3015
3016		CONFIG_SPL_RELOC_TEXT_BASE
3017		Address to relocate to.  If unspecified, this is equal to
3018		CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3019
3020		CONFIG_SPL_BSS_START_ADDR
3021		Link address for the BSS within the SPL binary.
3022
3023		CONFIG_SPL_BSS_MAX_SIZE
3024		Maximum size in memory allocated to the SPL BSS.
3025		When defined, the linker checks that the actual memory used
3026		by SPL from __bss_start to __bss_end does not exceed it.
3027		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3028		must not be both defined at the same time.
3029
3030		CONFIG_SPL_STACK
3031		Adress of the start of the stack SPL will use
3032
3033		CONFIG_SPL_RELOC_STACK
3034		Adress of the start of the stack SPL will use after
3035		relocation.  If unspecified, this is equal to
3036		CONFIG_SPL_STACK.
3037
3038		CONFIG_SYS_SPL_MALLOC_START
3039		Starting address of the malloc pool used in SPL.
3040
3041		CONFIG_SYS_SPL_MALLOC_SIZE
3042		The size of the malloc pool used in SPL.
3043
3044		CONFIG_SPL_FRAMEWORK
3045		Enable the SPL framework under common/.  This framework
3046		supports MMC, NAND and YMODEM loading of U-Boot and NAND
3047		NAND loading of the Linux Kernel.
3048
3049		CONFIG_SPL_DISPLAY_PRINT
3050		For ARM, enable an optional function to print more information
3051		about the running system.
3052
3053		CONFIG_SPL_INIT_MINIMAL
3054		Arch init code should be built for a very small image
3055
3056		CONFIG_SPL_LIBCOMMON_SUPPORT
3057		Support for common/libcommon.o in SPL binary
3058
3059		CONFIG_SPL_LIBDISK_SUPPORT
3060		Support for disk/libdisk.o in SPL binary
3061
3062		CONFIG_SPL_I2C_SUPPORT
3063		Support for drivers/i2c/libi2c.o in SPL binary
3064
3065		CONFIG_SPL_GPIO_SUPPORT
3066		Support for drivers/gpio/libgpio.o in SPL binary
3067
3068		CONFIG_SPL_MMC_SUPPORT
3069		Support for drivers/mmc/libmmc.o in SPL binary
3070
3071		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3072		CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3073		CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3074		Address, size and partition on the MMC to load U-Boot from
3075		when the MMC is being used in raw mode.
3076
3077		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3078		Sector to load kernel uImage from when MMC is being
3079		used in raw mode (for Falcon mode)
3080
3081		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3082		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3083		Sector and number of sectors to load kernel argument
3084		parameters from when MMC is being used in raw mode
3085		(for falcon mode)
3086
3087		CONFIG_SPL_FAT_SUPPORT
3088		Support for fs/fat/libfat.o in SPL binary
3089
3090		CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3091		Filename to read to load U-Boot when reading from FAT
3092
3093		CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3094		Filename to read to load kernel uImage when reading
3095		from FAT (for Falcon mode)
3096
3097		CONFIG_SPL_FAT_LOAD_ARGS_NAME
3098		Filename to read to load kernel argument parameters
3099		when reading from FAT (for Falcon mode)
3100
3101		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3102		Set this for NAND SPL on PPC mpc83xx targets, so that
3103		start.S waits for the rest of the SPL to load before
3104		continuing (the hardware starts execution after just
3105		loading the first page rather than the full 4K).
3106
3107		CONFIG_SPL_NAND_BASE
3108		Include nand_base.c in the SPL.  Requires
3109		CONFIG_SPL_NAND_DRIVERS.
3110
3111		CONFIG_SPL_NAND_DRIVERS
3112		SPL uses normal NAND drivers, not minimal drivers.
3113
3114		CONFIG_SPL_NAND_ECC
3115		Include standard software ECC in the SPL
3116
3117		CONFIG_SPL_NAND_SIMPLE
3118		Support for NAND boot using simple NAND drivers that
3119		expose the cmd_ctrl() interface.
3120
3121		CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3122		Set for the SPL on PPC mpc8xxx targets, support for
3123		arch/powerpc/cpu/mpc8xxx/ddr/libddr.o in SPL binary.
3124
3125		CONFIG_SPL_COMMON_INIT_DDR
3126		Set for common ddr init with serial presence detect in
3127		SPL binary.
3128
3129		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3130		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3131		CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3132		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3133		CONFIG_SYS_NAND_ECCBYTES
3134		Defines the size and behavior of the NAND that SPL uses
3135		to read U-Boot
3136
3137		CONFIG_SYS_NAND_U_BOOT_OFFS
3138		Location in NAND to read U-Boot from
3139
3140		CONFIG_SYS_NAND_U_BOOT_DST
3141		Location in memory to load U-Boot to
3142
3143		CONFIG_SYS_NAND_U_BOOT_SIZE
3144		Size of image to load
3145
3146		CONFIG_SYS_NAND_U_BOOT_START
3147		Entry point in loaded image to jump to
3148
3149		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3150		Define this if you need to first read the OOB and then the
3151		data. This is used for example on davinci plattforms.
3152
3153		CONFIG_SPL_OMAP3_ID_NAND
3154		Support for an OMAP3-specific set of functions to return the
3155		ID and MFR of the first attached NAND chip, if present.
3156
3157		CONFIG_SPL_SERIAL_SUPPORT
3158		Support for drivers/serial/libserial.o in SPL binary
3159
3160		CONFIG_SPL_SPI_FLASH_SUPPORT
3161		Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3162
3163		CONFIG_SPL_SPI_SUPPORT
3164		Support for drivers/spi/libspi.o in SPL binary
3165
3166		CONFIG_SPL_RAM_DEVICE
3167		Support for running image already present in ram, in SPL binary
3168
3169		CONFIG_SPL_LIBGENERIC_SUPPORT
3170		Support for lib/libgeneric.o in SPL binary
3171
3172		CONFIG_SPL_ENV_SUPPORT
3173		Support for the environment operating in SPL binary
3174
3175		CONFIG_SPL_NET_SUPPORT
3176		Support for the net/libnet.o in SPL binary.
3177		It conflicts with SPL env from storage medium specified by
3178		CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3179
3180		CONFIG_SPL_PAD_TO
3181		Image offset to which the SPL should be padded before appending
3182		the SPL payload. By default, this is defined as
3183		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3184		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3185		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3186
3187		CONFIG_SPL_TARGET
3188		Final target image containing SPL and payload.  Some SPLs
3189		use an arch-specific makefile fragment instead, for
3190		example if more than one image needs to be produced.
3191
3192		CONFIG_FIT_SPL_PRINT
3193		Printing information about a FIT image adds quite a bit of
3194		code to SPL. So this is normally disabled in SPL. Use this
3195		option to re-enable it. This will affect the output of the
3196		bootm command when booting a FIT image.
3197
3198- TPL framework
3199		CONFIG_TPL
3200		Enable building of TPL globally.
3201
3202		CONFIG_TPL_PAD_TO
3203		Image offset to which the TPL should be padded before appending
3204		the TPL payload. By default, this is defined as
3205		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3206		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3207		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3208
3209Modem Support:
3210--------------
3211
3212[so far only for SMDK2400 boards]
3213
3214- Modem support enable:
3215		CONFIG_MODEM_SUPPORT
3216
3217- RTS/CTS Flow control enable:
3218		CONFIG_HWFLOW
3219
3220- Modem debug support:
3221		CONFIG_MODEM_SUPPORT_DEBUG
3222
3223		Enables debugging stuff (char screen[1024], dbg())
3224		for modem support. Useful only with BDI2000.
3225
3226- Interrupt support (PPC):
3227
3228		There are common interrupt_init() and timer_interrupt()
3229		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3230		for CPU specific initialization. interrupt_init_cpu()
3231		should set decrementer_count to appropriate value. If
3232		CPU resets decrementer automatically after interrupt
3233		(ppc4xx) it should set decrementer_count to zero.
3234		timer_interrupt() calls timer_interrupt_cpu() for CPU
3235		specific handling. If board has watchdog / status_led
3236		/ other_activity_monitor it works automatically from
3237		general timer_interrupt().
3238
3239- General:
3240
3241		In the target system modem support is enabled when a
3242		specific key (key combination) is pressed during
3243		power-on. Otherwise U-Boot will boot normally
3244		(autoboot). The key_pressed() function is called from
3245		board_init(). Currently key_pressed() is a dummy
3246		function, returning 1 and thus enabling modem
3247		initialization.
3248
3249		If there are no modem init strings in the
3250		environment, U-Boot proceed to autoboot; the
3251		previous output (banner, info printfs) will be
3252		suppressed, though.
3253
3254		See also: doc/README.Modem
3255
3256Board initialization settings:
3257------------------------------
3258
3259During Initialization u-boot calls a number of board specific functions
3260to allow the preparation of board specific prerequisites, e.g. pin setup
3261before drivers are initialized. To enable these callbacks the
3262following configuration macros have to be defined. Currently this is
3263architecture specific, so please check arch/your_architecture/lib/board.c
3264typically in board_init_f() and board_init_r().
3265
3266- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3267- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3268- CONFIG_BOARD_LATE_INIT: Call board_late_init()
3269- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3270
3271Configuration Settings:
3272-----------------------
3273
3274- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3275		undefine this when you're short of memory.
3276
3277- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3278		width of the commands listed in the 'help' command output.
3279
3280- CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
3281		prompt for user input.
3282
3283- CONFIG_SYS_CBSIZE:	Buffer size for input from the Console
3284
3285- CONFIG_SYS_PBSIZE:	Buffer size for Console output
3286
3287- CONFIG_SYS_MAXARGS:	max. Number of arguments accepted for monitor commands
3288
3289- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3290		the application (usually a Linux kernel) when it is
3291		booted
3292
3293- CONFIG_SYS_BAUDRATE_TABLE:
3294		List of legal baudrate settings for this board.
3295
3296- CONFIG_SYS_CONSOLE_INFO_QUIET
3297		Suppress display of console information at boot.
3298
3299- CONFIG_SYS_CONSOLE_IS_IN_ENV
3300		If the board specific function
3301			extern int overwrite_console (void);
3302		returns 1, the stdin, stderr and stdout are switched to the
3303		serial port, else the settings in the environment are used.
3304
3305- CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3306		Enable the call to overwrite_console().
3307
3308- CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3309		Enable overwrite of previous console environment settings.
3310
3311- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3312		Begin and End addresses of the area used by the
3313		simple memory test.
3314
3315- CONFIG_SYS_ALT_MEMTEST:
3316		Enable an alternate, more extensive memory test.
3317
3318- CONFIG_SYS_MEMTEST_SCRATCH:
3319		Scratch address used by the alternate memory test
3320		You only need to set this if address zero isn't writeable
3321
3322- CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3323		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3324		this specified memory area will get subtracted from the top
3325		(end) of RAM and won't get "touched" at all by U-Boot. By
3326		fixing up gd->ram_size the Linux kernel should gets passed
3327		the now "corrected" memory size and won't touch it either.
3328		This should work for arch/ppc and arch/powerpc. Only Linux
3329		board ports in arch/powerpc with bootwrapper support that
3330		recalculate the memory size from the SDRAM controller setup
3331		will have to get fixed in Linux additionally.
3332
3333		This option can be used as a workaround for the 440EPx/GRx
3334		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3335		be touched.
3336
3337		WARNING: Please make sure that this value is a multiple of
3338		the Linux page size (normally 4k). If this is not the case,
3339		then the end address of the Linux memory will be located at a
3340		non page size aligned address and this could cause major
3341		problems.
3342
3343- CONFIG_SYS_LOADS_BAUD_CHANGE:
3344		Enable temporary baudrate change while serial download
3345
3346- CONFIG_SYS_SDRAM_BASE:
3347		Physical start address of SDRAM. _Must_ be 0 here.
3348
3349- CONFIG_SYS_MBIO_BASE:
3350		Physical start address of Motherboard I/O (if using a
3351		Cogent motherboard)
3352
3353- CONFIG_SYS_FLASH_BASE:
3354		Physical start address of Flash memory.
3355
3356- CONFIG_SYS_MONITOR_BASE:
3357		Physical start address of boot monitor code (set by
3358		make config files to be same as the text base address
3359		(CONFIG_SYS_TEXT_BASE) used when linking) - same as
3360		CONFIG_SYS_FLASH_BASE when booting from flash.
3361
3362- CONFIG_SYS_MONITOR_LEN:
3363		Size of memory reserved for monitor code, used to
3364		determine _at_compile_time_ (!) if the environment is
3365		embedded within the U-Boot image, or in a separate
3366		flash sector.
3367
3368- CONFIG_SYS_MALLOC_LEN:
3369		Size of DRAM reserved for malloc() use.
3370
3371- CONFIG_SYS_BOOTM_LEN:
3372		Normally compressed uImages are limited to an
3373		uncompressed size of 8 MBytes. If this is not enough,
3374		you can define CONFIG_SYS_BOOTM_LEN in your board config file
3375		to adjust this setting to your needs.
3376
3377- CONFIG_SYS_BOOTMAPSZ:
3378		Maximum size of memory mapped by the startup code of
3379		the Linux kernel; all data that must be processed by
3380		the Linux kernel (bd_info, boot arguments, FDT blob if
3381		used) must be put below this limit, unless "bootm_low"
3382		environment variable is defined and non-zero. In such case
3383		all data for the Linux kernel must be between "bootm_low"
3384		and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.	 The environment
3385		variable "bootm_mapsize" will override the value of
3386		CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
3387		then the value in "bootm_size" will be used instead.
3388
3389- CONFIG_SYS_BOOT_RAMDISK_HIGH:
3390		Enable initrd_high functionality.  If defined then the
3391		initrd_high feature is enabled and the bootm ramdisk subcommand
3392		is enabled.
3393
3394- CONFIG_SYS_BOOT_GET_CMDLINE:
3395		Enables allocating and saving kernel cmdline in space between
3396		"bootm_low" and "bootm_low" + BOOTMAPSZ.
3397
3398- CONFIG_SYS_BOOT_GET_KBD:
3399		Enables allocating and saving a kernel copy of the bd_info in
3400		space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3401
3402- CONFIG_SYS_MAX_FLASH_BANKS:
3403		Max number of Flash memory banks
3404
3405- CONFIG_SYS_MAX_FLASH_SECT:
3406		Max number of sectors on a Flash chip
3407
3408- CONFIG_SYS_FLASH_ERASE_TOUT:
3409		Timeout for Flash erase operations (in ms)
3410
3411- CONFIG_SYS_FLASH_WRITE_TOUT:
3412		Timeout for Flash write operations (in ms)
3413
3414- CONFIG_SYS_FLASH_LOCK_TOUT
3415		Timeout for Flash set sector lock bit operation (in ms)
3416
3417- CONFIG_SYS_FLASH_UNLOCK_TOUT
3418		Timeout for Flash clear lock bits operation (in ms)
3419
3420- CONFIG_SYS_FLASH_PROTECTION
3421		If defined, hardware flash sectors protection is used
3422		instead of U-Boot software protection.
3423
3424- CONFIG_SYS_DIRECT_FLASH_TFTP:
3425
3426		Enable TFTP transfers directly to flash memory;
3427		without this option such a download has to be
3428		performed in two steps: (1) download to RAM, and (2)
3429		copy from RAM to flash.
3430
3431		The two-step approach is usually more reliable, since
3432		you can check if the download worked before you erase
3433		the flash, but in some situations (when system RAM is
3434		too limited to allow for a temporary copy of the
3435		downloaded image) this option may be very useful.
3436
3437- CONFIG_SYS_FLASH_CFI:
3438		Define if the flash driver uses extra elements in the
3439		common flash structure for storing flash geometry.
3440
3441- CONFIG_FLASH_CFI_DRIVER
3442		This option also enables the building of the cfi_flash driver
3443		in the drivers directory
3444
3445- CONFIG_FLASH_CFI_MTD
3446		This option enables the building of the cfi_mtd driver
3447		in the drivers directory. The driver exports CFI flash
3448		to the MTD layer.
3449
3450- CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3451		Use buffered writes to flash.
3452
3453- CONFIG_FLASH_SPANSION_S29WS_N
3454		s29ws-n MirrorBit flash has non-standard addresses for buffered
3455		write commands.
3456
3457- CONFIG_SYS_FLASH_QUIET_TEST
3458		If this option is defined, the common CFI flash doesn't
3459		print it's warning upon not recognized FLASH banks. This
3460		is useful, if some of the configured banks are only
3461		optionally available.
3462
3463- CONFIG_FLASH_SHOW_PROGRESS
3464		If defined (must be an integer), print out countdown
3465		digits and dots.  Recommended value: 45 (9..1) for 80
3466		column displays, 15 (3..1) for 40 column displays.
3467
3468- CONFIG_FLASH_VERIFY
3469		If defined, the content of the flash (destination) is compared
3470		against the source after the write operation. An error message
3471		will be printed when the contents are not identical.
3472		Please note that this option is useless in nearly all cases,
3473		since such flash programming errors usually are detected earlier
3474		while unprotecting/erasing/programming. Please only enable
3475		this option if you really know what you are doing.
3476
3477- CONFIG_SYS_RX_ETH_BUFFER:
3478		Defines the number of Ethernet receive buffers. On some
3479		Ethernet controllers it is recommended to set this value
3480		to 8 or even higher (EEPRO100 or 405 EMAC), since all
3481		buffers can be full shortly after enabling the interface
3482		on high Ethernet traffic.
3483		Defaults to 4 if not defined.
3484
3485- CONFIG_ENV_MAX_ENTRIES
3486
3487	Maximum number of entries in the hash table that is used
3488	internally to store the environment settings. The default
3489	setting is supposed to be generous and should work in most
3490	cases. This setting can be used to tune behaviour; see
3491	lib/hashtable.c for details.
3492
3493- CONFIG_ENV_FLAGS_LIST_DEFAULT
3494- CONFIG_ENV_FLAGS_LIST_STATIC
3495	Enable validation of the values given to environment variables when
3496	calling env set.  Variables can be restricted to only decimal,
3497	hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
3498	the variables can also be restricted to IP address or MAC address.
3499
3500	The format of the list is:
3501		type_attribute = [s|d|x|b|i|m]
3502		access_atribute = [a|r|o|c]
3503		attributes = type_attribute[access_atribute]
3504		entry = variable_name[:attributes]
3505		list = entry[,list]
3506
3507	The type attributes are:
3508		s - String (default)
3509		d - Decimal
3510		x - Hexadecimal
3511		b - Boolean ([1yYtT|0nNfF])
3512		i - IP address
3513		m - MAC address
3514
3515	The access attributes are:
3516		a - Any (default)
3517		r - Read-only
3518		o - Write-once
3519		c - Change-default
3520
3521	- CONFIG_ENV_FLAGS_LIST_DEFAULT
3522		Define this to a list (string) to define the ".flags"
3523		envirnoment variable in the default or embedded environment.
3524
3525	- CONFIG_ENV_FLAGS_LIST_STATIC
3526		Define this to a list (string) to define validation that
3527		should be done if an entry is not found in the ".flags"
3528		environment variable.  To override a setting in the static
3529		list, simply add an entry for the same variable name to the
3530		".flags" variable.
3531
3532- CONFIG_ENV_ACCESS_IGNORE_FORCE
3533	If defined, don't allow the -f switch to env set override variable
3534	access flags.
3535
3536- CONFIG_SYS_GENERIC_BOARD
3537	This selects the architecture-generic board system instead of the
3538	architecture-specific board files. It is intended to move boards
3539	to this new framework over time. Defining this will disable the
3540	arch/foo/lib/board.c file and use common/board_f.c and
3541	common/board_r.c instead. To use this option your architecture
3542	must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3543	its config.mk file). If you find problems enabling this option on
3544	your board please report the problem and send patches!
3545
3546- CONFIG_SYS_SYM_OFFSETS
3547	This is set by architectures that use offsets for link symbols
3548	instead of absolute values. So bss_start is obtained using an
3549	offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3550	directly. You should not need to touch this setting.
3551
3552- CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3553	This is set by OMAP boards for the max time that reset should
3554	be asserted. See doc/README.omap-reset-time for details on how
3555	the value can be calulated on a given board.
3556
3557The following definitions that deal with the placement and management
3558of environment data (variable area); in general, we support the
3559following configurations:
3560
3561- CONFIG_BUILD_ENVCRC:
3562
3563	Builds up envcrc with the target environment so that external utils
3564	may easily extract it and embed it in final U-Boot images.
3565
3566- CONFIG_ENV_IS_IN_FLASH:
3567
3568	Define this if the environment is in flash memory.
3569
3570	a) The environment occupies one whole flash sector, which is
3571	   "embedded" in the text segment with the U-Boot code. This
3572	   happens usually with "bottom boot sector" or "top boot
3573	   sector" type flash chips, which have several smaller
3574	   sectors at the start or the end. For instance, such a
3575	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3576	   such a case you would place the environment in one of the
3577	   4 kB sectors - with U-Boot code before and after it. With
3578	   "top boot sector" type flash chips, you would put the
3579	   environment in one of the last sectors, leaving a gap
3580	   between U-Boot and the environment.
3581
3582	- CONFIG_ENV_OFFSET:
3583
3584	   Offset of environment data (variable area) to the
3585	   beginning of flash memory; for instance, with bottom boot
3586	   type flash chips the second sector can be used: the offset
3587	   for this sector is given here.
3588
3589	   CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3590
3591	- CONFIG_ENV_ADDR:
3592
3593	   This is just another way to specify the start address of
3594	   the flash sector containing the environment (instead of
3595	   CONFIG_ENV_OFFSET).
3596
3597	- CONFIG_ENV_SECT_SIZE:
3598
3599	   Size of the sector containing the environment.
3600
3601
3602	b) Sometimes flash chips have few, equal sized, BIG sectors.
3603	   In such a case you don't want to spend a whole sector for
3604	   the environment.
3605
3606	- CONFIG_ENV_SIZE:
3607
3608	   If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3609	   and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3610	   of this flash sector for the environment. This saves
3611	   memory for the RAM copy of the environment.
3612
3613	   It may also save flash memory if you decide to use this
3614	   when your environment is "embedded" within U-Boot code,
3615	   since then the remainder of the flash sector could be used
3616	   for U-Boot code. It should be pointed out that this is
3617	   STRONGLY DISCOURAGED from a robustness point of view:
3618	   updating the environment in flash makes it always
3619	   necessary to erase the WHOLE sector. If something goes
3620	   wrong before the contents has been restored from a copy in
3621	   RAM, your target system will be dead.
3622
3623	- CONFIG_ENV_ADDR_REDUND
3624	  CONFIG_ENV_SIZE_REDUND
3625
3626	   These settings describe a second storage area used to hold
3627	   a redundant copy of the environment data, so that there is
3628	   a valid backup copy in case there is a power failure during
3629	   a "saveenv" operation.
3630
3631BE CAREFUL! Any changes to the flash layout, and some changes to the
3632source code will make it necessary to adapt <board>/u-boot.lds*
3633accordingly!
3634
3635
3636- CONFIG_ENV_IS_IN_NVRAM:
3637
3638	Define this if you have some non-volatile memory device
3639	(NVRAM, battery buffered SRAM) which you want to use for the
3640	environment.
3641
3642	- CONFIG_ENV_ADDR:
3643	- CONFIG_ENV_SIZE:
3644
3645	  These two #defines are used to determine the memory area you
3646	  want to use for environment. It is assumed that this memory
3647	  can just be read and written to, without any special
3648	  provision.
3649
3650BE CAREFUL! The first access to the environment happens quite early
3651in U-Boot initalization (when we try to get the setting of for the
3652console baudrate). You *MUST* have mapped your NVRAM area then, or
3653U-Boot will hang.
3654
3655Please note that even with NVRAM we still use a copy of the
3656environment in RAM: we could work on NVRAM directly, but we want to
3657keep settings there always unmodified except somebody uses "saveenv"
3658to save the current settings.
3659
3660
3661- CONFIG_ENV_IS_IN_EEPROM:
3662
3663	Use this if you have an EEPROM or similar serial access
3664	device and a driver for it.
3665
3666	- CONFIG_ENV_OFFSET:
3667	- CONFIG_ENV_SIZE:
3668
3669	  These two #defines specify the offset and size of the
3670	  environment area within the total memory of your EEPROM.
3671
3672	- CONFIG_SYS_I2C_EEPROM_ADDR:
3673	  If defined, specified the chip address of the EEPROM device.
3674	  The default address is zero.
3675
3676	- CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3677	  If defined, the number of bits used to address bytes in a
3678	  single page in the EEPROM device.  A 64 byte page, for example
3679	  would require six bits.
3680
3681	- CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3682	  If defined, the number of milliseconds to delay between
3683	  page writes.	The default is zero milliseconds.
3684
3685	- CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3686	  The length in bytes of the EEPROM memory array address.  Note
3687	  that this is NOT the chip address length!
3688
3689	- CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3690	  EEPROM chips that implement "address overflow" are ones
3691	  like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3692	  address and the extra bits end up in the "chip address" bit
3693	  slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3694	  byte chips.
3695
3696	  Note that we consider the length of the address field to
3697	  still be one byte because the extra address bits are hidden
3698	  in the chip address.
3699
3700	- CONFIG_SYS_EEPROM_SIZE:
3701	  The size in bytes of the EEPROM device.
3702
3703	- CONFIG_ENV_EEPROM_IS_ON_I2C
3704	  define this, if you have I2C and SPI activated, and your
3705	  EEPROM, which holds the environment, is on the I2C bus.
3706
3707	- CONFIG_I2C_ENV_EEPROM_BUS
3708	  if you have an Environment on an EEPROM reached over
3709	  I2C muxes, you can define here, how to reach this
3710	  EEPROM. For example:
3711
3712	  #define CONFIG_I2C_ENV_EEPROM_BUS	  1
3713
3714	  EEPROM which holds the environment, is reached over
3715	  a pca9547 i2c mux with address 0x70, channel 3.
3716
3717- CONFIG_ENV_IS_IN_DATAFLASH:
3718
3719	Define this if you have a DataFlash memory device which you
3720	want to use for the environment.
3721
3722	- CONFIG_ENV_OFFSET:
3723	- CONFIG_ENV_ADDR:
3724	- CONFIG_ENV_SIZE:
3725
3726	  These three #defines specify the offset and size of the
3727	  environment area within the total memory of your DataFlash placed
3728	  at the specified address.
3729
3730- CONFIG_ENV_IS_IN_REMOTE:
3731
3732	Define this if you have a remote memory space which you
3733	want to use for the local device's environment.
3734
3735	- CONFIG_ENV_ADDR:
3736	- CONFIG_ENV_SIZE:
3737
3738	  These two #defines specify the address and size of the
3739	  environment area within the remote memory space. The
3740	  local device can get the environment from remote memory
3741	  space by SRIO or PCIE links.
3742
3743BE CAREFUL! For some special cases, the local device can not use
3744"saveenv" command. For example, the local device will get the
3745environment stored in a remote NOR flash by SRIO or PCIE link,
3746but it can not erase, write this NOR flash by SRIO or PCIE interface.
3747
3748- CONFIG_ENV_IS_IN_NAND:
3749
3750	Define this if you have a NAND device which you want to use
3751	for the environment.
3752
3753	- CONFIG_ENV_OFFSET:
3754	- CONFIG_ENV_SIZE:
3755
3756	  These two #defines specify the offset and size of the environment
3757	  area within the first NAND device.  CONFIG_ENV_OFFSET must be
3758	  aligned to an erase block boundary.
3759
3760	- CONFIG_ENV_OFFSET_REDUND (optional):
3761
3762	  This setting describes a second storage area of CONFIG_ENV_SIZE
3763	  size used to hold a redundant copy of the environment data, so
3764	  that there is a valid backup copy in case there is a power failure
3765	  during a "saveenv" operation.	 CONFIG_ENV_OFFSET_RENDUND must be
3766	  aligned to an erase block boundary.
3767
3768	- CONFIG_ENV_RANGE (optional):
3769
3770	  Specifies the length of the region in which the environment
3771	  can be written.  This should be a multiple of the NAND device's
3772	  block size.  Specifying a range with more erase blocks than
3773	  are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3774	  the range to be avoided.
3775
3776	- CONFIG_ENV_OFFSET_OOB (optional):
3777
3778	  Enables support for dynamically retrieving the offset of the
3779	  environment from block zero's out-of-band data.  The
3780	  "nand env.oob" command can be used to record this offset.
3781	  Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3782	  using CONFIG_ENV_OFFSET_OOB.
3783
3784- CONFIG_NAND_ENV_DST
3785
3786	Defines address in RAM to which the nand_spl code should copy the
3787	environment. If redundant environment is used, it will be copied to
3788	CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3789
3790- CONFIG_ENV_IS_IN_UBI:
3791
3792	Define this if you have an UBI volume that you want to use for the
3793	environment.  This has the benefit of wear-leveling the environment
3794	accesses, which is important on NAND.
3795
3796	- CONFIG_ENV_UBI_PART:
3797
3798	  Define this to a string that is the mtd partition containing the UBI.
3799
3800	- CONFIG_ENV_UBI_VOLUME:
3801
3802	  Define this to the name of the volume that you want to store the
3803	  environment in.
3804
3805	- CONFIG_ENV_UBI_VOLUME_REDUND:
3806
3807	  Define this to the name of another volume to store a second copy of
3808	  the environment in.  This will enable redundant environments in UBI.
3809	  It is assumed that both volumes are in the same MTD partition.
3810
3811	- CONFIG_UBI_SILENCE_MSG
3812	- CONFIG_UBIFS_SILENCE_MSG
3813
3814	  You will probably want to define these to avoid a really noisy system
3815	  when storing the env in UBI.
3816
3817- CONFIG_ENV_IS_IN_MMC:
3818
3819	Define this if you have an MMC device which you want to use for the
3820	environment.
3821
3822	- CONFIG_SYS_MMC_ENV_DEV:
3823
3824	  Specifies which MMC device the environment is stored in.
3825
3826	- CONFIG_SYS_MMC_ENV_PART (optional):
3827
3828	  Specifies which MMC partition the environment is stored in. If not
3829	  set, defaults to partition 0, the user area. Common values might be
3830	  1 (first MMC boot partition), 2 (second MMC boot partition).
3831
3832	- CONFIG_ENV_OFFSET:
3833	- CONFIG_ENV_SIZE:
3834
3835	  These two #defines specify the offset and size of the environment
3836	  area within the specified MMC device.
3837
3838	  If offset is positive (the usual case), it is treated as relative to
3839	  the start of the MMC partition. If offset is negative, it is treated
3840	  as relative to the end of the MMC partition. This can be useful if
3841	  your board may be fitted with different MMC devices, which have
3842	  different sizes for the MMC partitions, and you always want the
3843	  environment placed at the very end of the partition, to leave the
3844	  maximum possible space before it, to store other data.
3845
3846	  These two values are in units of bytes, but must be aligned to an
3847	  MMC sector boundary.
3848
3849	- CONFIG_ENV_OFFSET_REDUND (optional):
3850
3851	  Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3852	  hold a redundant copy of the environment data. This provides a
3853	  valid backup copy in case the other copy is corrupted, e.g. due
3854	  to a power failure during a "saveenv" operation.
3855
3856	  This value may also be positive or negative; this is handled in the
3857	  same way as CONFIG_ENV_OFFSET.
3858
3859	  This value is also in units of bytes, but must also be aligned to
3860	  an MMC sector boundary.
3861
3862	- CONFIG_ENV_SIZE_REDUND (optional):
3863
3864	  This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3865	  set. If this value is set, it must be set to the same value as
3866	  CONFIG_ENV_SIZE.
3867
3868- CONFIG_SYS_SPI_INIT_OFFSET
3869
3870	Defines offset to the initial SPI buffer area in DPRAM. The
3871	area is used at an early stage (ROM part) if the environment
3872	is configured to reside in the SPI EEPROM: We need a 520 byte
3873	scratch DPRAM area. It is used between the two initialization
3874	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3875	to be a good choice since it makes it far enough from the
3876	start of the data area as well as from the stack pointer.
3877
3878Please note that the environment is read-only until the monitor
3879has been relocated to RAM and a RAM copy of the environment has been
3880created; also, when using EEPROM you will have to use getenv_f()
3881until then to read environment variables.
3882
3883The environment is protected by a CRC32 checksum. Before the monitor
3884is relocated into RAM, as a result of a bad CRC you will be working
3885with the compiled-in default environment - *silently*!!! [This is
3886necessary, because the first environment variable we need is the
3887"baudrate" setting for the console - if we have a bad CRC, we don't
3888have any device yet where we could complain.]
3889
3890Note: once the monitor has been relocated, then it will complain if
3891the default environment is used; a new CRC is computed as soon as you
3892use the "saveenv" command to store a valid environment.
3893
3894- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3895		Echo the inverted Ethernet link state to the fault LED.
3896
3897		Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3898		      also needs to be defined.
3899
3900- CONFIG_SYS_FAULT_MII_ADDR:
3901		MII address of the PHY to check for the Ethernet link state.
3902
3903- CONFIG_NS16550_MIN_FUNCTIONS:
3904		Define this if you desire to only have use of the NS16550_init
3905		and NS16550_putc functions for the serial driver located at
3906		drivers/serial/ns16550.c.  This option is useful for saving
3907		space for already greatly restricted images, including but not
3908		limited to NAND_SPL configurations.
3909
3910- CONFIG_DISPLAY_BOARDINFO
3911		Display information about the board that U-Boot is running on
3912		when U-Boot starts up. The board function checkboard() is called
3913		to do this.
3914
3915- CONFIG_DISPLAY_BOARDINFO_LATE
3916		Similar to the previous option, but display this information
3917		later, once stdio is running and output goes to the LCD, if
3918		present.
3919
3920Low Level (hardware related) configuration options:
3921---------------------------------------------------
3922
3923- CONFIG_SYS_CACHELINE_SIZE:
3924		Cache Line Size of the CPU.
3925
3926- CONFIG_SYS_DEFAULT_IMMR:
3927		Default address of the IMMR after system reset.
3928
3929		Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3930		and RPXsuper) to be able to adjust the position of
3931		the IMMR register after a reset.
3932
3933- CONFIG_SYS_CCSRBAR_DEFAULT:
3934		Default (power-on reset) physical address of CCSR on Freescale
3935		PowerPC SOCs.
3936
3937- CONFIG_SYS_CCSRBAR:
3938		Virtual address of CCSR.  On a 32-bit build, this is typically
3939		the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3940
3941		CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3942		for cross-platform code that uses that macro instead.
3943
3944- CONFIG_SYS_CCSRBAR_PHYS:
3945		Physical address of CCSR.  CCSR can be relocated to a new
3946		physical address, if desired.  In this case, this macro should
3947		be set to that address.	 Otherwise, it should be set to the
3948		same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
3949		is typically relocated on 36-bit builds.  It is recommended
3950		that this macro be defined via the _HIGH and _LOW macros:
3951
3952		#define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3953			* 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3954
3955- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3956		Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS.	This value is typically
3957		either 0 (32-bit build) or 0xF (36-bit build).	This macro is
3958		used in assembly code, so it must not contain typecasts or
3959		integer size suffixes (e.g. "ULL").
3960
3961- CONFIG_SYS_CCSRBAR_PHYS_LOW:
3962		Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS.  This macro is
3963		used in assembly code, so it must not contain typecasts or
3964		integer size suffixes (e.g. "ULL").
3965
3966- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3967		If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3968		forced to a value that ensures that CCSR is not relocated.
3969
3970- Floppy Disk Support:
3971		CONFIG_SYS_FDC_DRIVE_NUMBER
3972
3973		the default drive number (default value 0)
3974
3975		CONFIG_SYS_ISA_IO_STRIDE
3976
3977		defines the spacing between FDC chipset registers
3978		(default value 1)
3979
3980		CONFIG_SYS_ISA_IO_OFFSET
3981
3982		defines the offset of register from address. It
3983		depends on which part of the data bus is connected to
3984		the FDC chipset. (default value 0)
3985
3986		If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3987		CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3988		default value.
3989
3990		if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3991		fdc_hw_init() is called at the beginning of the FDC
3992		setup. fdc_hw_init() must be provided by the board
3993		source code. It is used to make hardware dependant
3994		initializations.
3995
3996- CONFIG_IDE_AHB:
3997		Most IDE controllers were designed to be connected with PCI
3998		interface. Only few of them were designed for AHB interface.
3999		When software is doing ATA command and data transfer to
4000		IDE devices through IDE-AHB controller, some additional
4001		registers accessing to these kind of IDE-AHB controller
4002		is requierd.
4003
4004- CONFIG_SYS_IMMR:	Physical address of the Internal Memory.
4005		DO NOT CHANGE unless you know exactly what you're
4006		doing! (11-4) [MPC8xx/82xx systems only]
4007
4008- CONFIG_SYS_INIT_RAM_ADDR:
4009
4010		Start address of memory area that can be used for
4011		initial data and stack; please note that this must be
4012		writable memory that is working WITHOUT special
4013		initialization, i. e. you CANNOT use normal RAM which
4014		will become available only after programming the
4015		memory controller and running certain initialization
4016		sequences.
4017
4018		U-Boot uses the following memory types:
4019		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4020		- MPC824X: data cache
4021		- PPC4xx:  data cache
4022
4023- CONFIG_SYS_GBL_DATA_OFFSET:
4024
4025		Offset of the initial data structure in the memory
4026		area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4027		CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4028		data is located at the end of the available space
4029		(sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4030		CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4031		below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4032		CONFIG_SYS_GBL_DATA_OFFSET) downward.
4033
4034	Note:
4035		On the MPC824X (or other systems that use the data
4036		cache for initial memory) the address chosen for
4037		CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4038		point to an otherwise UNUSED address space between
4039		the top of RAM and the start of the PCI space.
4040
4041- CONFIG_SYS_SIUMCR:	SIU Module Configuration (11-6)
4042
4043- CONFIG_SYS_SYPCR:	System Protection Control (11-9)
4044
4045- CONFIG_SYS_TBSCR:	Time Base Status and Control (11-26)
4046
4047- CONFIG_SYS_PISCR:	Periodic Interrupt Status and Control (11-31)
4048
4049- CONFIG_SYS_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
4050
4051- CONFIG_SYS_SCCR:	System Clock and reset Control Register (15-27)
4052
4053- CONFIG_SYS_OR_TIMING_SDRAM:
4054		SDRAM timing
4055
4056- CONFIG_SYS_MAMR_PTA:
4057		periodic timer for refresh
4058
4059- CONFIG_SYS_DER:	Debug Event Register (37-47)
4060
4061- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4062  CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4063  CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4064  CONFIG_SYS_BR1_PRELIM:
4065		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4066
4067- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4068  CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4069  CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4070		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4071
4072- CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4073  CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4074		Machine Mode Register and Memory Periodic Timer
4075		Prescaler definitions (SDRAM timing)
4076
4077- CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4078		enable I2C microcode relocation patch (MPC8xx);
4079		define relocation offset in DPRAM [DSP2]
4080
4081- CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4082		enable SMC microcode relocation patch (MPC8xx);
4083		define relocation offset in DPRAM [SMC1]
4084
4085- CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4086		enable SPI microcode relocation patch (MPC8xx);
4087		define relocation offset in DPRAM [SCC4]
4088
4089- CONFIG_SYS_USE_OSCCLK:
4090		Use OSCM clock mode on MBX8xx board. Be careful,
4091		wrong setting might damage your board. Read
4092		doc/README.MBX before setting this variable!
4093
4094- CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4095		Offset of the bootmode word in DPRAM used by post
4096		(Power On Self Tests). This definition overrides
4097		#define'd default value in commproc.h resp.
4098		cpm_8260.h.
4099
4100- CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4101  CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4102  CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4103  CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4104  CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4105  CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4106  CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4107  CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4108		Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4109
4110- CONFIG_PCI_DISABLE_PCIE:
4111		Disable PCI-Express on systems where it is supported but not
4112		required.
4113
4114- CONFIG_PCI_ENUM_ONLY
4115		Only scan through and get the devices on the busses.
4116		Don't do any setup work, presumably because someone or
4117		something has already done it, and we don't need to do it
4118		a second time.	Useful for platforms that are pre-booted
4119		by coreboot or similar.
4120
4121- CONFIG_PCI_INDIRECT_BRIDGE:
4122		Enable support for indirect PCI bridges.
4123
4124- CONFIG_SYS_SRIO:
4125		Chip has SRIO or not
4126
4127- CONFIG_SRIO1:
4128		Board has SRIO 1 port available
4129
4130- CONFIG_SRIO2:
4131		Board has SRIO 2 port available
4132
4133- CONFIG_SRIO_PCIE_BOOT_MASTER
4134		Board can support master function for Boot from SRIO and PCIE
4135
4136- CONFIG_SYS_SRIOn_MEM_VIRT:
4137		Virtual Address of SRIO port 'n' memory region
4138
4139- CONFIG_SYS_SRIOn_MEM_PHYS:
4140		Physical Address of SRIO port 'n' memory region
4141
4142- CONFIG_SYS_SRIOn_MEM_SIZE:
4143		Size of SRIO port 'n' memory region
4144
4145- CONFIG_SYS_NAND_BUSWIDTH_16BIT
4146		Defined to tell the NAND controller that the NAND chip is using
4147		a 16 bit bus.
4148		Not all NAND drivers use this symbol.
4149		Example of drivers that use it:
4150		- drivers/mtd/nand/ndfc.c
4151		- drivers/mtd/nand/mxc_nand.c
4152
4153- CONFIG_SYS_NDFC_EBC0_CFG
4154		Sets the EBC0_CFG register for the NDFC. If not defined
4155		a default value will be used.
4156
4157- CONFIG_SPD_EEPROM
4158		Get DDR timing information from an I2C EEPROM. Common
4159		with pluggable memory modules such as SODIMMs
4160
4161  SPD_EEPROM_ADDRESS
4162		I2C address of the SPD EEPROM
4163
4164- CONFIG_SYS_SPD_BUS_NUM
4165		If SPD EEPROM is on an I2C bus other than the first
4166		one, specify here. Note that the value must resolve
4167		to something your driver can deal with.
4168
4169- CONFIG_SYS_DDR_RAW_TIMING
4170		Get DDR timing information from other than SPD. Common with
4171		soldered DDR chips onboard without SPD. DDR raw timing
4172		parameters are extracted from datasheet and hard-coded into
4173		header files or board specific files.
4174
4175- CONFIG_FSL_DDR_INTERACTIVE
4176		Enable interactive DDR debugging. See doc/README.fsl-ddr.
4177
4178- CONFIG_SYS_83XX_DDR_USES_CS0
4179		Only for 83xx systems. If specified, then DDR should
4180		be configured using CS0 and CS1 instead of CS2 and CS3.
4181
4182- CONFIG_ETHER_ON_FEC[12]
4183		Define to enable FEC[12] on a 8xx series processor.
4184
4185- CONFIG_FEC[12]_PHY
4186		Define to the hardcoded PHY address which corresponds
4187		to the given FEC; i. e.
4188			#define CONFIG_FEC1_PHY 4
4189		means that the PHY with address 4 is connected to FEC1
4190
4191		When set to -1, means to probe for first available.
4192
4193- CONFIG_FEC[12]_PHY_NORXERR
4194		The PHY does not have a RXERR line (RMII only).
4195		(so program the FEC to ignore it).
4196
4197- CONFIG_RMII
4198		Enable RMII mode for all FECs.
4199		Note that this is a global option, we can't
4200		have one FEC in standard MII mode and another in RMII mode.
4201
4202- CONFIG_CRC32_VERIFY
4203		Add a verify option to the crc32 command.
4204		The syntax is:
4205
4206		=> crc32 -v <address> <count> <crc32>
4207
4208		Where address/count indicate a memory area
4209		and crc32 is the correct crc32 which the
4210		area should have.
4211
4212- CONFIG_LOOPW
4213		Add the "loopw" memory command. This only takes effect if
4214		the memory commands are activated globally (CONFIG_CMD_MEM).
4215
4216- CONFIG_MX_CYCLIC
4217		Add the "mdc" and "mwc" memory commands. These are cyclic
4218		"md/mw" commands.
4219		Examples:
4220
4221		=> mdc.b 10 4 500
4222		This command will print 4 bytes (10,11,12,13) each 500 ms.
4223
4224		=> mwc.l 100 12345678 10
4225		This command will write 12345678 to address 100 all 10 ms.
4226
4227		This only takes effect if the memory commands are activated
4228		globally (CONFIG_CMD_MEM).
4229
4230- CONFIG_SKIP_LOWLEVEL_INIT
4231		[ARM, NDS32, MIPS only] If this variable is defined, then certain
4232		low level initializations (like setting up the memory
4233		controller) are omitted and/or U-Boot does not
4234		relocate itself into RAM.
4235
4236		Normally this variable MUST NOT be defined. The only
4237		exception is when U-Boot is loaded (to RAM) by some
4238		other boot loader or by a debugger which performs
4239		these initializations itself.
4240
4241- CONFIG_SPL_BUILD
4242		Modifies the behaviour of start.S when compiling a loader
4243		that is executed before the actual U-Boot. E.g. when
4244		compiling a NAND SPL.
4245
4246- CONFIG_TPL_BUILD
4247		Modifies the behaviour of start.S  when compiling a loader
4248		that is executed after the SPL and before the actual U-Boot.
4249		It is loaded by the SPL.
4250
4251- CONFIG_SYS_MPC85XX_NO_RESETVEC
4252		Only for 85xx systems. If this variable is specified, the section
4253		.resetvec is not kept and the section .bootpg is placed in the
4254		previous 4k of the .text section.
4255
4256- CONFIG_ARCH_MAP_SYSMEM
4257		Generally U-Boot (and in particular the md command) uses
4258		effective address. It is therefore not necessary to regard
4259		U-Boot address as virtual addresses that need to be translated
4260		to physical addresses. However, sandbox requires this, since
4261		it maintains its own little RAM buffer which contains all
4262		addressable memory. This option causes some memory accesses
4263		to be mapped through map_sysmem() / unmap_sysmem().
4264
4265- CONFIG_USE_ARCH_MEMCPY
4266  CONFIG_USE_ARCH_MEMSET
4267		If these options are used a optimized version of memcpy/memset will
4268		be used if available. These functions may be faster under some
4269		conditions but may increase the binary size.
4270
4271- CONFIG_X86_RESET_VECTOR
4272		If defined, the x86 reset vector code is included. This is not
4273		needed when U-Boot is running from Coreboot.
4274
4275- CONFIG_SYS_MPUCLK
4276		Defines the MPU clock speed (in MHz).
4277
4278		NOTE : currently only supported on AM335x platforms.
4279
4280Freescale QE/FMAN Firmware Support:
4281-----------------------------------
4282
4283The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4284loading of "firmware", which is encoded in the QE firmware binary format.
4285This firmware often needs to be loaded during U-Boot booting, so macros
4286are used to identify the storage device (NOR flash, SPI, etc) and the address
4287within that device.
4288
4289- CONFIG_SYS_QE_FMAN_FW_ADDR
4290	The address in the storage device where the firmware is located.  The
4291	meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4292	is also specified.
4293
4294- CONFIG_SYS_QE_FMAN_FW_LENGTH
4295	The maximum possible size of the firmware.  The firmware binary format
4296	has a field that specifies the actual size of the firmware, but it
4297	might not be possible to read any part of the firmware unless some
4298	local storage is allocated to hold the entire firmware first.
4299
4300- CONFIG_SYS_QE_FMAN_FW_IN_NOR
4301	Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4302	normal addressable memory via the LBC.  CONFIG_SYS_FMAN_FW_ADDR is the
4303	virtual address in NOR flash.
4304
4305- CONFIG_SYS_QE_FMAN_FW_IN_NAND
4306	Specifies that QE/FMAN firmware is located in NAND flash.
4307	CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4308
4309- CONFIG_SYS_QE_FMAN_FW_IN_MMC
4310	Specifies that QE/FMAN firmware is located on the primary SD/MMC
4311	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4312
4313- CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4314	Specifies that QE/FMAN firmware is located on the primary SPI
4315	device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4316
4317- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4318	Specifies that QE/FMAN firmware is located in the remote (master)
4319	memory space.	CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4320	can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4321	window->master inbound window->master LAW->the ucode address in
4322	master's memory space.
4323
4324Building the Software:
4325======================
4326
4327Building U-Boot has been tested in several native build environments
4328and in many different cross environments. Of course we cannot support
4329all possibly existing versions of cross development tools in all
4330(potentially obsolete) versions. In case of tool chain problems we
4331recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4332which is extensively used to build and test U-Boot.
4333
4334If you are not using a native environment, it is assumed that you
4335have GNU cross compiling tools available in your path. In this case,
4336you must set the environment variable CROSS_COMPILE in your shell.
4337Note that no changes to the Makefile or any other source files are
4338necessary. For example using the ELDK on a 4xx CPU, please enter:
4339
4340	$ CROSS_COMPILE=ppc_4xx-
4341	$ export CROSS_COMPILE
4342
4343Note: If you wish to generate Windows versions of the utilities in
4344      the tools directory you can use the MinGW toolchain
4345      (http://www.mingw.org).  Set your HOST tools to the MinGW
4346      toolchain and execute 'make tools'.  For example:
4347
4348       $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4349
4350      Binaries such as tools/mkimage.exe will be created which can
4351      be executed on computers running Windows.
4352
4353U-Boot is intended to be simple to build. After installing the
4354sources you must configure U-Boot for one specific board type. This
4355is done by typing:
4356
4357	make NAME_config
4358
4359where "NAME_config" is the name of one of the existing configu-
4360rations; see boards.cfg for supported names.
4361
4362Note: for some board special configuration names may exist; check if
4363      additional information is available from the board vendor; for
4364      instance, the TQM823L systems are available without (standard)
4365      or with LCD support. You can select such additional "features"
4366      when choosing the configuration, i. e.
4367
4368      make TQM823L_config
4369	- will configure for a plain TQM823L, i. e. no LCD support
4370
4371      make TQM823L_LCD_config
4372	- will configure for a TQM823L with U-Boot console on LCD
4373
4374      etc.
4375
4376
4377Finally, type "make all", and you should get some working U-Boot
4378images ready for download to / installation on your system:
4379
4380- "u-boot.bin" is a raw binary image
4381- "u-boot" is an image in ELF binary format
4382- "u-boot.srec" is in Motorola S-Record format
4383
4384By default the build is performed locally and the objects are saved
4385in the source directory. One of the two methods can be used to change
4386this behavior and build U-Boot to some external directory:
4387
43881. Add O= to the make command line invocations:
4389
4390	make O=/tmp/build distclean
4391	make O=/tmp/build NAME_config
4392	make O=/tmp/build all
4393
43942. Set environment variable BUILD_DIR to point to the desired location:
4395
4396	export BUILD_DIR=/tmp/build
4397	make distclean
4398	make NAME_config
4399	make all
4400
4401Note that the command line "O=" setting overrides the BUILD_DIR environment
4402variable.
4403
4404
4405Please be aware that the Makefiles assume you are using GNU make, so
4406for instance on NetBSD you might need to use "gmake" instead of
4407native "make".
4408
4409
4410If the system board that you have is not listed, then you will need
4411to port U-Boot to your hardware platform. To do this, follow these
4412steps:
4413
44141.  Add a new configuration option for your board to the toplevel
4415    "boards.cfg" file, using the existing entries as examples.
4416    Follow the instructions there to keep the boards in order.
44172.  Create a new directory to hold your board specific code. Add any
4418    files you need. In your board directory, you will need at least
4419    the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
44203.  Create a new configuration file "include/configs/<board>.h" for
4421    your board
44223.  If you're porting U-Boot to a new CPU, then also create a new
4423    directory to hold your CPU specific code. Add any files you need.
44244.  Run "make <board>_config" with your new name.
44255.  Type "make", and you should get a working "u-boot.srec" file
4426    to be installed on your target system.
44276.  Debug and solve any problems that might arise.
4428    [Of course, this last step is much harder than it sounds.]
4429
4430
4431Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4432==============================================================
4433
4434If you have modified U-Boot sources (for instance added a new board
4435or support for new devices, a new CPU, etc.) you are expected to
4436provide feedback to the other developers. The feedback normally takes
4437the form of a "patch", i. e. a context diff against a certain (latest
4438official or latest in the git repository) version of U-Boot sources.
4439
4440But before you submit such a patch, please verify that your modifi-
4441cation did not break existing code. At least make sure that *ALL* of
4442the supported boards compile WITHOUT ANY compiler warnings. To do so,
4443just run the "MAKEALL" script, which will configure and build U-Boot
4444for ALL supported system. Be warned, this will take a while. You can
4445select which (cross) compiler to use by passing a `CROSS_COMPILE'
4446environment variable to the script, i. e. to use the ELDK cross tools
4447you can type
4448
4449	CROSS_COMPILE=ppc_8xx- MAKEALL
4450
4451or to build on a native PowerPC system you can type
4452
4453	CROSS_COMPILE=' ' MAKEALL
4454
4455When using the MAKEALL script, the default behaviour is to build
4456U-Boot in the source directory. This location can be changed by
4457setting the BUILD_DIR environment variable. Also, for each target
4458built, the MAKEALL script saves two log files (<target>.ERR and
4459<target>.MAKEALL) in the <source dir>/LOG directory. This default
4460location can be changed by setting the MAKEALL_LOGDIR environment
4461variable. For example:
4462
4463	export BUILD_DIR=/tmp/build
4464	export MAKEALL_LOGDIR=/tmp/log
4465	CROSS_COMPILE=ppc_8xx- MAKEALL
4466
4467With the above settings build objects are saved in the /tmp/build,
4468log files are saved in the /tmp/log and the source tree remains clean
4469during the whole build process.
4470
4471
4472See also "U-Boot Porting Guide" below.
4473
4474
4475Monitor Commands - Overview:
4476============================
4477
4478go	- start application at address 'addr'
4479run	- run commands in an environment variable
4480bootm	- boot application image from memory
4481bootp	- boot image via network using BootP/TFTP protocol
4482bootz   - boot zImage from memory
4483tftpboot- boot image via network using TFTP protocol
4484	       and env variables "ipaddr" and "serverip"
4485	       (and eventually "gatewayip")
4486tftpput - upload a file via network using TFTP protocol
4487rarpboot- boot image via network using RARP/TFTP protocol
4488diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
4489loads	- load S-Record file over serial line
4490loadb	- load binary file over serial line (kermit mode)
4491md	- memory display
4492mm	- memory modify (auto-incrementing)
4493nm	- memory modify (constant address)
4494mw	- memory write (fill)
4495cp	- memory copy
4496cmp	- memory compare
4497crc32	- checksum calculation
4498i2c	- I2C sub-system
4499sspi	- SPI utility commands
4500base	- print or set address offset
4501printenv- print environment variables
4502setenv	- set environment variables
4503saveenv - save environment variables to persistent storage
4504protect - enable or disable FLASH write protection
4505erase	- erase FLASH memory
4506flinfo	- print FLASH memory information
4507nand	- NAND memory operations (see doc/README.nand)
4508bdinfo	- print Board Info structure
4509iminfo	- print header information for application image
4510coninfo - print console devices and informations
4511ide	- IDE sub-system
4512loop	- infinite loop on address range
4513loopw	- infinite write loop on address range
4514mtest	- simple RAM test
4515icache	- enable or disable instruction cache
4516dcache	- enable or disable data cache
4517reset	- Perform RESET of the CPU
4518echo	- echo args to console
4519version - print monitor version
4520help	- print online help
4521?	- alias for 'help'
4522
4523
4524Monitor Commands - Detailed Description:
4525========================================
4526
4527TODO.
4528
4529For now: just type "help <command>".
4530
4531
4532Environment Variables:
4533======================
4534
4535U-Boot supports user configuration using Environment Variables which
4536can be made persistent by saving to Flash memory.
4537
4538Environment Variables are set using "setenv", printed using
4539"printenv", and saved to Flash using "saveenv". Using "setenv"
4540without a value can be used to delete a variable from the
4541environment. As long as you don't save the environment you are
4542working with an in-memory copy. In case the Flash area containing the
4543environment is erased by accident, a default environment is provided.
4544
4545Some configuration options can be set using Environment Variables.
4546
4547List of environment variables (most likely not complete):
4548
4549  baudrate	- see CONFIG_BAUDRATE
4550
4551  bootdelay	- see CONFIG_BOOTDELAY
4552
4553  bootcmd	- see CONFIG_BOOTCOMMAND
4554
4555  bootargs	- Boot arguments when booting an RTOS image
4556
4557  bootfile	- Name of the image to load with TFTP
4558
4559  bootm_low	- Memory range available for image processing in the bootm
4560		  command can be restricted. This variable is given as
4561		  a hexadecimal number and defines lowest address allowed
4562		  for use by the bootm command. See also "bootm_size"
4563		  environment variable. Address defined by "bootm_low" is
4564		  also the base of the initial memory mapping for the Linux
4565		  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4566		  bootm_mapsize.
4567
4568  bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4569		  This variable is given as a hexadecimal number and it
4570		  defines the size of the memory region starting at base
4571		  address bootm_low that is accessible by the Linux kernel
4572		  during early boot.  If unset, CONFIG_SYS_BOOTMAPSZ is used
4573		  as the default value if it is defined, and bootm_size is
4574		  used otherwise.
4575
4576  bootm_size	- Memory range available for image processing in the bootm
4577		  command can be restricted. This variable is given as
4578		  a hexadecimal number and defines the size of the region
4579		  allowed for use by the bootm command. See also "bootm_low"
4580		  environment variable.
4581
4582  updatefile	- Location of the software update file on a TFTP server, used
4583		  by the automatic software update feature. Please refer to
4584		  documentation in doc/README.update for more details.
4585
4586  autoload	- if set to "no" (any string beginning with 'n'),
4587		  "bootp" will just load perform a lookup of the
4588		  configuration from the BOOTP server, but not try to
4589		  load any image using TFTP
4590
4591  autostart	- if set to "yes", an image loaded using the "bootp",
4592		  "rarpboot", "tftpboot" or "diskboot" commands will
4593		  be automatically started (by internally calling
4594		  "bootm")
4595
4596		  If set to "no", a standalone image passed to the
4597		  "bootm" command will be copied to the load address
4598		  (and eventually uncompressed), but NOT be started.
4599		  This can be used to load and uncompress arbitrary
4600		  data.
4601
4602  fdt_high	- if set this restricts the maximum address that the
4603		  flattened device tree will be copied into upon boot.
4604		  For example, if you have a system with 1 GB memory
4605		  at physical address 0x10000000, while Linux kernel
4606		  only recognizes the first 704 MB as low memory, you
4607		  may need to set fdt_high as 0x3C000000 to have the
4608		  device tree blob be copied to the maximum address
4609		  of the 704 MB low memory, so that Linux kernel can
4610		  access it during the boot procedure.
4611
4612		  If this is set to the special value 0xFFFFFFFF then
4613		  the fdt will not be copied at all on boot.  For this
4614		  to work it must reside in writable memory, have
4615		  sufficient padding on the end of it for u-boot to
4616		  add the information it needs into it, and the memory
4617		  must be accessible by the kernel.
4618
4619  fdtcontroladdr- if set this is the address of the control flattened
4620		  device tree used by U-Boot when CONFIG_OF_CONTROL is
4621		  defined.
4622
4623  i2cfast	- (PPC405GP|PPC405EP only)
4624		  if set to 'y' configures Linux I2C driver for fast
4625		  mode (400kHZ). This environment variable is used in
4626		  initialization code. So, for changes to be effective
4627		  it must be saved and board must be reset.
4628
4629  initrd_high	- restrict positioning of initrd images:
4630		  If this variable is not set, initrd images will be
4631		  copied to the highest possible address in RAM; this
4632		  is usually what you want since it allows for
4633		  maximum initrd size. If for some reason you want to
4634		  make sure that the initrd image is loaded below the
4635		  CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4636		  variable to a value of "no" or "off" or "0".
4637		  Alternatively, you can set it to a maximum upper
4638		  address to use (U-Boot will still check that it
4639		  does not overwrite the U-Boot stack and data).
4640
4641		  For instance, when you have a system with 16 MB
4642		  RAM, and want to reserve 4 MB from use by Linux,
4643		  you can do this by adding "mem=12M" to the value of
4644		  the "bootargs" variable. However, now you must make
4645		  sure that the initrd image is placed in the first
4646		  12 MB as well - this can be done with
4647
4648		  setenv initrd_high 00c00000
4649
4650		  If you set initrd_high to 0xFFFFFFFF, this is an
4651		  indication to U-Boot that all addresses are legal
4652		  for the Linux kernel, including addresses in flash
4653		  memory. In this case U-Boot will NOT COPY the
4654		  ramdisk at all. This may be useful to reduce the
4655		  boot time on your system, but requires that this
4656		  feature is supported by your Linux kernel.
4657
4658  ipaddr	- IP address; needed for tftpboot command
4659
4660  loadaddr	- Default load address for commands like "bootp",
4661		  "rarpboot", "tftpboot", "loadb" or "diskboot"
4662
4663  loads_echo	- see CONFIG_LOADS_ECHO
4664
4665  serverip	- TFTP server IP address; needed for tftpboot command
4666
4667  bootretry	- see CONFIG_BOOT_RETRY_TIME
4668
4669  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
4670
4671  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
4672
4673  ethprime	- controls which interface is used first.
4674
4675  ethact	- controls which interface is currently active.
4676		  For example you can do the following
4677
4678		  => setenv ethact FEC
4679		  => ping 192.168.0.1 # traffic sent on FEC
4680		  => setenv ethact SCC
4681		  => ping 10.0.0.1 # traffic sent on SCC
4682
4683  ethrotate	- When set to "no" U-Boot does not go through all
4684		  available network interfaces.
4685		  It just stays at the currently selected interface.
4686
4687  netretry	- When set to "no" each network operation will
4688		  either succeed or fail without retrying.
4689		  When set to "once" the network operation will
4690		  fail when all the available network interfaces
4691		  are tried once without success.
4692		  Useful on scripts which control the retry operation
4693		  themselves.
4694
4695  npe_ucode	- set load address for the NPE microcode
4696
4697  silent_linux  - If set then linux will be told to boot silently, by
4698		  changing the console to be empty. If "yes" it will be
4699		  made silent. If "no" it will not be made silent. If
4700		  unset, then it will be made silent if the U-Boot console
4701		  is silent.
4702
4703  tftpsrcport	- If this is set, the value is used for TFTP's
4704		  UDP source port.
4705
4706  tftpdstport	- If this is set, the value is used for TFTP's UDP
4707		  destination port instead of the Well Know Port 69.
4708
4709  tftpblocksize - Block size to use for TFTP transfers; if not set,
4710		  we use the TFTP server's default block size
4711
4712  tftptimeout	- Retransmission timeout for TFTP packets (in milli-
4713		  seconds, minimum value is 1000 = 1 second). Defines
4714		  when a packet is considered to be lost so it has to
4715		  be retransmitted. The default is 5000 = 5 seconds.
4716		  Lowering this value may make downloads succeed
4717		  faster in networks with high packet loss rates or
4718		  with unreliable TFTP servers.
4719
4720  vlan		- When set to a value < 4095 the traffic over
4721		  Ethernet is encapsulated/received over 802.1q
4722		  VLAN tagged frames.
4723
4724The following image location variables contain the location of images
4725used in booting. The "Image" column gives the role of the image and is
4726not an environment variable name. The other columns are environment
4727variable names. "File Name" gives the name of the file on a TFTP
4728server, "RAM Address" gives the location in RAM the image will be
4729loaded to, and "Flash Location" gives the image's address in NOR
4730flash or offset in NAND flash.
4731
4732*Note* - these variables don't have to be defined for all boards, some
4733boards currenlty use other variables for these purposes, and some
4734boards use these variables for other purposes.
4735
4736Image		    File Name	     RAM Address       Flash Location
4737-----		    ---------	     -----------       --------------
4738u-boot		    u-boot	     u-boot_addr_r     u-boot_addr
4739Linux kernel	    bootfile	     kernel_addr_r     kernel_addr
4740device tree blob    fdtfile	     fdt_addr_r	       fdt_addr
4741ramdisk		    ramdiskfile	     ramdisk_addr_r    ramdisk_addr
4742
4743The following environment variables may be used and automatically
4744updated by the network boot commands ("bootp" and "rarpboot"),
4745depending the information provided by your boot server:
4746
4747  bootfile	- see above
4748  dnsip		- IP address of your Domain Name Server
4749  dnsip2	- IP address of your secondary Domain Name Server
4750  gatewayip	- IP address of the Gateway (Router) to use
4751  hostname	- Target hostname
4752  ipaddr	- see above
4753  netmask	- Subnet Mask
4754  rootpath	- Pathname of the root filesystem on the NFS server
4755  serverip	- see above
4756
4757
4758There are two special Environment Variables:
4759
4760  serial#	- contains hardware identification information such
4761		  as type string and/or serial number
4762  ethaddr	- Ethernet address
4763
4764These variables can be set only once (usually during manufacturing of
4765the board). U-Boot refuses to delete or overwrite these variables
4766once they have been set once.
4767
4768
4769Further special Environment Variables:
4770
4771  ver		- Contains the U-Boot version string as printed
4772		  with the "version" command. This variable is
4773		  readonly (see CONFIG_VERSION_VARIABLE).
4774
4775
4776Please note that changes to some configuration parameters may take
4777only effect after the next boot (yes, that's just like Windoze :-).
4778
4779
4780Callback functions for environment variables:
4781---------------------------------------------
4782
4783For some environment variables, the behavior of u-boot needs to change
4784when their values are changed.  This functionailty allows functions to
4785be associated with arbitrary variables.  On creation, overwrite, or
4786deletion, the callback will provide the opportunity for some side
4787effect to happen or for the change to be rejected.
4788
4789The callbacks are named and associated with a function using the
4790U_BOOT_ENV_CALLBACK macro in your board or driver code.
4791
4792These callbacks are associated with variables in one of two ways.  The
4793static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4794in the board configuration to a string that defines a list of
4795associations.  The list must be in the following format:
4796
4797	entry = variable_name[:callback_name]
4798	list = entry[,list]
4799
4800If the callback name is not specified, then the callback is deleted.
4801Spaces are also allowed anywhere in the list.
4802
4803Callbacks can also be associated by defining the ".callbacks" variable
4804with the same list format above.  Any association in ".callbacks" will
4805override any association in the static list. You can define
4806CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4807".callbacks" envirnoment variable in the default or embedded environment.
4808
4809
4810Command Line Parsing:
4811=====================
4812
4813There are two different command line parsers available with U-Boot:
4814the old "simple" one, and the much more powerful "hush" shell:
4815
4816Old, simple command line parser:
4817--------------------------------
4818
4819- supports environment variables (through setenv / saveenv commands)
4820- several commands on one line, separated by ';'
4821- variable substitution using "... ${name} ..." syntax
4822- special characters ('$', ';') can be escaped by prefixing with '\',
4823  for example:
4824	setenv bootcmd bootm \${address}
4825- You can also escape text by enclosing in single apostrophes, for example:
4826	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4827
4828Hush shell:
4829-----------
4830
4831- similar to Bourne shell, with control structures like
4832  if...then...else...fi, for...do...done; while...do...done,
4833  until...do...done, ...
4834- supports environment ("global") variables (through setenv / saveenv
4835  commands) and local shell variables (through standard shell syntax
4836  "name=value"); only environment variables can be used with "run"
4837  command
4838
4839General rules:
4840--------------
4841
4842(1) If a command line (or an environment variable executed by a "run"
4843    command) contains several commands separated by semicolon, and
4844    one of these commands fails, then the remaining commands will be
4845    executed anyway.
4846
4847(2) If you execute several variables with one call to run (i. e.
4848    calling run with a list of variables as arguments), any failing
4849    command will cause "run" to terminate, i. e. the remaining
4850    variables are not executed.
4851
4852Note for Redundant Ethernet Interfaces:
4853=======================================
4854
4855Some boards come with redundant Ethernet interfaces; U-Boot supports
4856such configurations and is capable of automatic selection of a
4857"working" interface when needed. MAC assignment works as follows:
4858
4859Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4860MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4861"eth1addr" (=>eth1), "eth2addr", ...
4862
4863If the network interface stores some valid MAC address (for instance
4864in SROM), this is used as default address if there is NO correspon-
4865ding setting in the environment; if the corresponding environment
4866variable is set, this overrides the settings in the card; that means:
4867
4868o If the SROM has a valid MAC address, and there is no address in the
4869  environment, the SROM's address is used.
4870
4871o If there is no valid address in the SROM, and a definition in the
4872  environment exists, then the value from the environment variable is
4873  used.
4874
4875o If both the SROM and the environment contain a MAC address, and
4876  both addresses are the same, this MAC address is used.
4877
4878o If both the SROM and the environment contain a MAC address, and the
4879  addresses differ, the value from the environment is used and a
4880  warning is printed.
4881
4882o If neither SROM nor the environment contain a MAC address, an error
4883  is raised.
4884
4885If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4886will be programmed into hardware as part of the initialization process.	 This
4887may be skipped by setting the appropriate 'ethmacskip' environment variable.
4888The naming convention is as follows:
4889"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4890
4891Image Formats:
4892==============
4893
4894U-Boot is capable of booting (and performing other auxiliary operations on)
4895images in two formats:
4896
4897New uImage format (FIT)
4898-----------------------
4899
4900Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4901to Flattened Device Tree). It allows the use of images with multiple
4902components (several kernels, ramdisks, etc.), with contents protected by
4903SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4904
4905
4906Old uImage format
4907-----------------
4908
4909Old image format is based on binary files which can be basically anything,
4910preceded by a special header; see the definitions in include/image.h for
4911details; basically, the header defines the following image properties:
4912
4913* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4914  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4915  LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4916  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4917  INTEGRITY).
4918* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4919  IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4920  Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4921* Compression Type (uncompressed, gzip, bzip2)
4922* Load Address
4923* Entry Point
4924* Image Name
4925* Image Timestamp
4926
4927The header is marked by a special Magic Number, and both the header
4928and the data portions of the image are secured against corruption by
4929CRC32 checksums.
4930
4931
4932Linux Support:
4933==============
4934
4935Although U-Boot should support any OS or standalone application
4936easily, the main focus has always been on Linux during the design of
4937U-Boot.
4938
4939U-Boot includes many features that so far have been part of some
4940special "boot loader" code within the Linux kernel. Also, any
4941"initrd" images to be used are no longer part of one big Linux image;
4942instead, kernel and "initrd" are separate images. This implementation
4943serves several purposes:
4944
4945- the same features can be used for other OS or standalone
4946  applications (for instance: using compressed images to reduce the
4947  Flash memory footprint)
4948
4949- it becomes much easier to port new Linux kernel versions because
4950  lots of low-level, hardware dependent stuff are done by U-Boot
4951
4952- the same Linux kernel image can now be used with different "initrd"
4953  images; of course this also means that different kernel images can
4954  be run with the same "initrd". This makes testing easier (you don't
4955  have to build a new "zImage.initrd" Linux image when you just
4956  change a file in your "initrd"). Also, a field-upgrade of the
4957  software is easier now.
4958
4959
4960Linux HOWTO:
4961============
4962
4963Porting Linux to U-Boot based systems:
4964---------------------------------------
4965
4966U-Boot cannot save you from doing all the necessary modifications to
4967configure the Linux device drivers for use with your target hardware
4968(no, we don't intend to provide a full virtual machine interface to
4969Linux :-).
4970
4971But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4972
4973Just make sure your machine specific header file (for instance
4974include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4975Information structure as we define in include/asm-<arch>/u-boot.h,
4976and make sure that your definition of IMAP_ADDR uses the same value
4977as your U-Boot configuration in CONFIG_SYS_IMMR.
4978
4979
4980Configuring the Linux kernel:
4981-----------------------------
4982
4983No specific requirements for U-Boot. Make sure you have some root
4984device (initial ramdisk, NFS) for your target system.
4985
4986
4987Building a Linux Image:
4988-----------------------
4989
4990With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4991not used. If you use recent kernel source, a new build target
4992"uImage" will exist which automatically builds an image usable by
4993U-Boot. Most older kernels also have support for a "pImage" target,
4994which was introduced for our predecessor project PPCBoot and uses a
4995100% compatible format.
4996
4997Example:
4998
4999	make TQM850L_config
5000	make oldconfig
5001	make dep
5002	make uImage
5003
5004The "uImage" build target uses a special tool (in 'tools/mkimage') to
5005encapsulate a compressed Linux kernel image with header	 information,
5006CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5007
5008* build a standard "vmlinux" kernel image (in ELF binary format):
5009
5010* convert the kernel into a raw binary image:
5011
5012	${CROSS_COMPILE}-objcopy -O binary \
5013				 -R .note -R .comment \
5014				 -S vmlinux linux.bin
5015
5016* compress the binary image:
5017
5018	gzip -9 linux.bin
5019
5020* package compressed binary image for U-Boot:
5021
5022	mkimage -A ppc -O linux -T kernel -C gzip \
5023		-a 0 -e 0 -n "Linux Kernel Image" \
5024		-d linux.bin.gz uImage
5025
5026
5027The "mkimage" tool can also be used to create ramdisk images for use
5028with U-Boot, either separated from the Linux kernel image, or
5029combined into one file. "mkimage" encapsulates the images with a 64
5030byte header containing information about target architecture,
5031operating system, image type, compression method, entry points, time
5032stamp, CRC32 checksums, etc.
5033
5034"mkimage" can be called in two ways: to verify existing images and
5035print the header information, or to build new images.
5036
5037In the first form (with "-l" option) mkimage lists the information
5038contained in the header of an existing U-Boot image; this includes
5039checksum verification:
5040
5041	tools/mkimage -l image
5042	  -l ==> list image header information
5043
5044The second form (with "-d" option) is used to build a U-Boot image
5045from a "data file" which is used as image payload:
5046
5047	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5048		      -n name -d data_file image
5049	  -A ==> set architecture to 'arch'
5050	  -O ==> set operating system to 'os'
5051	  -T ==> set image type to 'type'
5052	  -C ==> set compression type 'comp'
5053	  -a ==> set load address to 'addr' (hex)
5054	  -e ==> set entry point to 'ep' (hex)
5055	  -n ==> set image name to 'name'
5056	  -d ==> use image data from 'datafile'
5057
5058Right now, all Linux kernels for PowerPC systems use the same load
5059address (0x00000000), but the entry point address depends on the
5060kernel version:
5061
5062- 2.2.x kernels have the entry point at 0x0000000C,
5063- 2.3.x and later kernels have the entry point at 0x00000000.
5064
5065So a typical call to build a U-Boot image would read:
5066
5067	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5068	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5069	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5070	> examples/uImage.TQM850L
5071	Image Name:   2.4.4 kernel for TQM850L
5072	Created:      Wed Jul 19 02:34:59 2000
5073	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5074	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5075	Load Address: 0x00000000
5076	Entry Point:  0x00000000
5077
5078To verify the contents of the image (or check for corruption):
5079
5080	-> tools/mkimage -l examples/uImage.TQM850L
5081	Image Name:   2.4.4 kernel for TQM850L
5082	Created:      Wed Jul 19 02:34:59 2000
5083	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
5084	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
5085	Load Address: 0x00000000
5086	Entry Point:  0x00000000
5087
5088NOTE: for embedded systems where boot time is critical you can trade
5089speed for memory and install an UNCOMPRESSED image instead: this
5090needs more space in Flash, but boots much faster since it does not
5091need to be uncompressed:
5092
5093	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5094	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5095	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5096	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5097	> examples/uImage.TQM850L-uncompressed
5098	Image Name:   2.4.4 kernel for TQM850L
5099	Created:      Wed Jul 19 02:34:59 2000
5100	Image Type:   PowerPC Linux Kernel Image (uncompressed)
5101	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
5102	Load Address: 0x00000000
5103	Entry Point:  0x00000000
5104
5105
5106Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5107when your kernel is intended to use an initial ramdisk:
5108
5109	-> tools/mkimage -n 'Simple Ramdisk Image' \
5110	> -A ppc -O linux -T ramdisk -C gzip \
5111	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5112	Image Name:   Simple Ramdisk Image
5113	Created:      Wed Jan 12 14:01:50 2000
5114	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
5115	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
5116	Load Address: 0x00000000
5117	Entry Point:  0x00000000
5118
5119
5120Installing a Linux Image:
5121-------------------------
5122
5123To downloading a U-Boot image over the serial (console) interface,
5124you must convert the image to S-Record format:
5125
5126	objcopy -I binary -O srec examples/image examples/image.srec
5127
5128The 'objcopy' does not understand the information in the U-Boot
5129image header, so the resulting S-Record file will be relative to
5130address 0x00000000. To load it to a given address, you need to
5131specify the target address as 'offset' parameter with the 'loads'
5132command.
5133
5134Example: install the image to address 0x40100000 (which on the
5135TQM8xxL is in the first Flash bank):
5136
5137	=> erase 40100000 401FFFFF
5138
5139	.......... done
5140	Erased 8 sectors
5141
5142	=> loads 40100000
5143	## Ready for S-Record download ...
5144	~>examples/image.srec
5145	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5146	...
5147	15989 15990 15991 15992
5148	[file transfer complete]
5149	[connected]
5150	## Start Addr = 0x00000000
5151
5152
5153You can check the success of the download using the 'iminfo' command;
5154this includes a checksum verification so you can be sure no data
5155corruption happened:
5156
5157	=> imi 40100000
5158
5159	## Checking Image at 40100000 ...
5160	   Image Name:	 2.2.13 for initrd on TQM850L
5161	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5162	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5163	   Load Address: 00000000
5164	   Entry Point:	 0000000c
5165	   Verifying Checksum ... OK
5166
5167
5168Boot Linux:
5169-----------
5170
5171The "bootm" command is used to boot an application that is stored in
5172memory (RAM or Flash). In case of a Linux kernel image, the contents
5173of the "bootargs" environment variable is passed to the kernel as
5174parameters. You can check and modify this variable using the
5175"printenv" and "setenv" commands:
5176
5177
5178	=> printenv bootargs
5179	bootargs=root=/dev/ram
5180
5181	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5182
5183	=> printenv bootargs
5184	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5185
5186	=> bootm 40020000
5187	## Booting Linux kernel at 40020000 ...
5188	   Image Name:	 2.2.13 for NFS on TQM850L
5189	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5190	   Data Size:	 381681 Bytes = 372 kB = 0 MB
5191	   Load Address: 00000000
5192	   Entry Point:	 0000000c
5193	   Verifying Checksum ... OK
5194	   Uncompressing Kernel Image ... OK
5195	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
5196	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5197	time_init: decrementer frequency = 187500000/60
5198	Calibrating delay loop... 49.77 BogoMIPS
5199	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5200	...
5201
5202If you want to boot a Linux kernel with initial RAM disk, you pass
5203the memory addresses of both the kernel and the initrd image (PPBCOOT
5204format!) to the "bootm" command:
5205
5206	=> imi 40100000 40200000
5207
5208	## Checking Image at 40100000 ...
5209	   Image Name:	 2.2.13 for initrd on TQM850L
5210	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5211	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5212	   Load Address: 00000000
5213	   Entry Point:	 0000000c
5214	   Verifying Checksum ... OK
5215
5216	## Checking Image at 40200000 ...
5217	   Image Name:	 Simple Ramdisk Image
5218	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5219	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5220	   Load Address: 00000000
5221	   Entry Point:	 00000000
5222	   Verifying Checksum ... OK
5223
5224	=> bootm 40100000 40200000
5225	## Booting Linux kernel at 40100000 ...
5226	   Image Name:	 2.2.13 for initrd on TQM850L
5227	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5228	   Data Size:	 335725 Bytes = 327 kB = 0 MB
5229	   Load Address: 00000000
5230	   Entry Point:	 0000000c
5231	   Verifying Checksum ... OK
5232	   Uncompressing Kernel Image ... OK
5233	## Loading RAMDisk Image at 40200000 ...
5234	   Image Name:	 Simple Ramdisk Image
5235	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
5236	   Data Size:	 566530 Bytes = 553 kB = 0 MB
5237	   Load Address: 00000000
5238	   Entry Point:	 00000000
5239	   Verifying Checksum ... OK
5240	   Loading Ramdisk ... OK
5241	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
5242	Boot arguments: root=/dev/ram
5243	time_init: decrementer frequency = 187500000/60
5244	Calibrating delay loop... 49.77 BogoMIPS
5245	...
5246	RAMDISK: Compressed image found at block 0
5247	VFS: Mounted root (ext2 filesystem).
5248
5249	bash#
5250
5251Boot Linux and pass a flat device tree:
5252-----------
5253
5254First, U-Boot must be compiled with the appropriate defines. See the section
5255titled "Linux Kernel Interface" above for a more in depth explanation. The
5256following is an example of how to start a kernel and pass an updated
5257flat device tree:
5258
5259=> print oftaddr
5260oftaddr=0x300000
5261=> print oft
5262oft=oftrees/mpc8540ads.dtb
5263=> tftp $oftaddr $oft
5264Speed: 1000, full duplex
5265Using TSEC0 device
5266TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5267Filename 'oftrees/mpc8540ads.dtb'.
5268Load address: 0x300000
5269Loading: #
5270done
5271Bytes transferred = 4106 (100a hex)
5272=> tftp $loadaddr $bootfile
5273Speed: 1000, full duplex
5274Using TSEC0 device
5275TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5276Filename 'uImage'.
5277Load address: 0x200000
5278Loading:############
5279done
5280Bytes transferred = 1029407 (fb51f hex)
5281=> print loadaddr
5282loadaddr=200000
5283=> print oftaddr
5284oftaddr=0x300000
5285=> bootm $loadaddr - $oftaddr
5286## Booting image at 00200000 ...
5287   Image Name:	 Linux-2.6.17-dirty
5288   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
5289   Data Size:	 1029343 Bytes = 1005.2 kB
5290   Load Address: 00000000
5291   Entry Point:	 00000000
5292   Verifying Checksum ... OK
5293   Uncompressing Kernel Image ... OK
5294Booting using flat device tree at 0x300000
5295Using MPC85xx ADS machine description
5296Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5297[snip]
5298
5299
5300More About U-Boot Image Types:
5301------------------------------
5302
5303U-Boot supports the following image types:
5304
5305   "Standalone Programs" are directly runnable in the environment
5306	provided by U-Boot; it is expected that (if they behave
5307	well) you can continue to work in U-Boot after return from
5308	the Standalone Program.
5309   "OS Kernel Images" are usually images of some Embedded OS which
5310	will take over control completely. Usually these programs
5311	will install their own set of exception handlers, device
5312	drivers, set up the MMU, etc. - this means, that you cannot
5313	expect to re-enter U-Boot except by resetting the CPU.
5314   "RAMDisk Images" are more or less just data blocks, and their
5315	parameters (address, size) are passed to an OS kernel that is
5316	being started.
5317   "Multi-File Images" contain several images, typically an OS
5318	(Linux) kernel image and one or more data images like
5319	RAMDisks. This construct is useful for instance when you want
5320	to boot over the network using BOOTP etc., where the boot
5321	server provides just a single image file, but you want to get
5322	for instance an OS kernel and a RAMDisk image.
5323
5324	"Multi-File Images" start with a list of image sizes, each
5325	image size (in bytes) specified by an "uint32_t" in network
5326	byte order. This list is terminated by an "(uint32_t)0".
5327	Immediately after the terminating 0 follow the images, one by
5328	one, all aligned on "uint32_t" boundaries (size rounded up to
5329	a multiple of 4 bytes).
5330
5331   "Firmware Images" are binary images containing firmware (like
5332	U-Boot or FPGA images) which usually will be programmed to
5333	flash memory.
5334
5335   "Script files" are command sequences that will be executed by
5336	U-Boot's command interpreter; this feature is especially
5337	useful when you configure U-Boot to use a real shell (hush)
5338	as command interpreter.
5339
5340Booting the Linux zImage:
5341-------------------------
5342
5343On some platforms, it's possible to boot Linux zImage. This is done
5344using the "bootz" command. The syntax of "bootz" command is the same
5345as the syntax of "bootm" command.
5346
5347Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5348kernel with raw initrd images. The syntax is slightly different, the
5349address of the initrd must be augmented by it's size, in the following
5350format: "<initrd addres>:<initrd size>".
5351
5352
5353Standalone HOWTO:
5354=================
5355
5356One of the features of U-Boot is that you can dynamically load and
5357run "standalone" applications, which can use some resources of
5358U-Boot like console I/O functions or interrupt services.
5359
5360Two simple examples are included with the sources:
5361
5362"Hello World" Demo:
5363-------------------
5364
5365'examples/hello_world.c' contains a small "Hello World" Demo
5366application; it is automatically compiled when you build U-Boot.
5367It's configured to run at address 0x00040004, so you can play with it
5368like that:
5369
5370	=> loads
5371	## Ready for S-Record download ...
5372	~>examples/hello_world.srec
5373	1 2 3 4 5 6 7 8 9 10 11 ...
5374	[file transfer complete]
5375	[connected]
5376	## Start Addr = 0x00040004
5377
5378	=> go 40004 Hello World! This is a test.
5379	## Starting application at 0x00040004 ...
5380	Hello World
5381	argc = 7
5382	argv[0] = "40004"
5383	argv[1] = "Hello"
5384	argv[2] = "World!"
5385	argv[3] = "This"
5386	argv[4] = "is"
5387	argv[5] = "a"
5388	argv[6] = "test."
5389	argv[7] = "<NULL>"
5390	Hit any key to exit ...
5391
5392	## Application terminated, rc = 0x0
5393
5394Another example, which demonstrates how to register a CPM interrupt
5395handler with the U-Boot code, can be found in 'examples/timer.c'.
5396Here, a CPM timer is set up to generate an interrupt every second.
5397The interrupt service routine is trivial, just printing a '.'
5398character, but this is just a demo program. The application can be
5399controlled by the following keys:
5400
5401	? - print current values og the CPM Timer registers
5402	b - enable interrupts and start timer
5403	e - stop timer and disable interrupts
5404	q - quit application
5405
5406	=> loads
5407	## Ready for S-Record download ...
5408	~>examples/timer.srec
5409	1 2 3 4 5 6 7 8 9 10 11 ...
5410	[file transfer complete]
5411	[connected]
5412	## Start Addr = 0x00040004
5413
5414	=> go 40004
5415	## Starting application at 0x00040004 ...
5416	TIMERS=0xfff00980
5417	Using timer 1
5418	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5419
5420Hit 'b':
5421	[q, b, e, ?] Set interval 1000000 us
5422	Enabling timer
5423Hit '?':
5424	[q, b, e, ?] ........
5425	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5426Hit '?':
5427	[q, b, e, ?] .
5428	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5429Hit '?':
5430	[q, b, e, ?] .
5431	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5432Hit '?':
5433	[q, b, e, ?] .
5434	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5435Hit 'e':
5436	[q, b, e, ?] ...Stopping timer
5437Hit 'q':
5438	[q, b, e, ?] ## Application terminated, rc = 0x0
5439
5440
5441Minicom warning:
5442================
5443
5444Over time, many people have reported problems when trying to use the
5445"minicom" terminal emulation program for serial download. I (wd)
5446consider minicom to be broken, and recommend not to use it. Under
5447Unix, I recommend to use C-Kermit for general purpose use (and
5448especially for kermit binary protocol download ("loadb" command), and
5449use "cu" for S-Record download ("loads" command).  See
5450http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5451for help with kermit.
5452
5453
5454Nevertheless, if you absolutely want to use it try adding this
5455configuration to your "File transfer protocols" section:
5456
5457	   Name	   Program			Name U/D FullScr IO-Red. Multi
5458	X  kermit  /usr/bin/kermit -i -l %l -s	 Y    U	   Y	   N	  N
5459	Y  kermit  /usr/bin/kermit -i -l %l -r	 N    D	   Y	   N	  N
5460
5461
5462NetBSD Notes:
5463=============
5464
5465Starting at version 0.9.2, U-Boot supports NetBSD both as host
5466(build U-Boot) and target system (boots NetBSD/mpc8xx).
5467
5468Building requires a cross environment; it is known to work on
5469NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5470need gmake since the Makefiles are not compatible with BSD make).
5471Note that the cross-powerpc package does not install include files;
5472attempting to build U-Boot will fail because <machine/ansi.h> is
5473missing.  This file has to be installed and patched manually:
5474
5475	# cd /usr/pkg/cross/powerpc-netbsd/include
5476	# mkdir powerpc
5477	# ln -s powerpc machine
5478	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5479	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
5480
5481Native builds *don't* work due to incompatibilities between native
5482and U-Boot include files.
5483
5484Booting assumes that (the first part of) the image booted is a
5485stage-2 loader which in turn loads and then invokes the kernel
5486proper. Loader sources will eventually appear in the NetBSD source
5487tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5488meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5489
5490
5491Implementation Internals:
5492=========================
5493
5494The following is not intended to be a complete description of every
5495implementation detail. However, it should help to understand the
5496inner workings of U-Boot and make it easier to port it to custom
5497hardware.
5498
5499
5500Initial Stack, Global Data:
5501---------------------------
5502
5503The implementation of U-Boot is complicated by the fact that U-Boot
5504starts running out of ROM (flash memory), usually without access to
5505system RAM (because the memory controller is not initialized yet).
5506This means that we don't have writable Data or BSS segments, and BSS
5507is not initialized as zero. To be able to get a C environment working
5508at all, we have to allocate at least a minimal stack. Implementation
5509options for this are defined and restricted by the CPU used: Some CPU
5510models provide on-chip memory (like the IMMR area on MPC8xx and
5511MPC826x processors), on others (parts of) the data cache can be
5512locked as (mis-) used as memory, etc.
5513
5514	Chris Hallinan posted a good summary of these issues to the
5515	U-Boot mailing list:
5516
5517	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5518	From: "Chris Hallinan" <clh@net1plus.com>
5519	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5520	...
5521
5522	Correct me if I'm wrong, folks, but the way I understand it
5523	is this: Using DCACHE as initial RAM for Stack, etc, does not
5524	require any physical RAM backing up the cache. The cleverness
5525	is that the cache is being used as a temporary supply of
5526	necessary storage before the SDRAM controller is setup. It's
5527	beyond the scope of this list to explain the details, but you
5528	can see how this works by studying the cache architecture and
5529	operation in the architecture and processor-specific manuals.
5530
5531	OCM is On Chip Memory, which I believe the 405GP has 4K. It
5532	is another option for the system designer to use as an
5533	initial stack/RAM area prior to SDRAM being available. Either
5534	option should work for you. Using CS 4 should be fine if your
5535	board designers haven't used it for something that would
5536	cause you grief during the initial boot! It is frequently not
5537	used.
5538
5539	CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5540	with your processor/board/system design. The default value
5541	you will find in any recent u-boot distribution in
5542	walnut.h should work for you. I'd set it to a value larger
5543	than your SDRAM module. If you have a 64MB SDRAM module, set
5544	it above 400_0000. Just make sure your board has no resources
5545	that are supposed to respond to that address! That code in
5546	start.S has been around a while and should work as is when
5547	you get the config right.
5548
5549	-Chris Hallinan
5550	DS4.COM, Inc.
5551
5552It is essential to remember this, since it has some impact on the C
5553code for the initialization procedures:
5554
5555* Initialized global data (data segment) is read-only. Do not attempt
5556  to write it.
5557
5558* Do not use any uninitialized global data (or implicitely initialized
5559  as zero data - BSS segment) at all - this is undefined, initiali-
5560  zation is performed later (when relocating to RAM).
5561
5562* Stack space is very limited. Avoid big data buffers or things like
5563  that.
5564
5565Having only the stack as writable memory limits means we cannot use
5566normal global data to share information beween the code. But it
5567turned out that the implementation of U-Boot can be greatly
5568simplified by making a global data structure (gd_t) available to all
5569functions. We could pass a pointer to this data as argument to _all_
5570functions, but this would bloat the code. Instead we use a feature of
5571the GCC compiler (Global Register Variables) to share the data: we
5572place a pointer (gd) to the global data into a register which we
5573reserve for this purpose.
5574
5575When choosing a register for such a purpose we are restricted by the
5576relevant  (E)ABI  specifications for the current architecture, and by
5577GCC's implementation.
5578
5579For PowerPC, the following registers have specific use:
5580	R1:	stack pointer
5581	R2:	reserved for system use
5582	R3-R4:	parameter passing and return values
5583	R5-R10: parameter passing
5584	R13:	small data area pointer
5585	R30:	GOT pointer
5586	R31:	frame pointer
5587
5588	(U-Boot also uses R12 as internal GOT pointer. r12
5589	is a volatile register so r12 needs to be reset when
5590	going back and forth between asm and C)
5591
5592    ==> U-Boot will use R2 to hold a pointer to the global data
5593
5594    Note: on PPC, we could use a static initializer (since the
5595    address of the global data structure is known at compile time),
5596    but it turned out that reserving a register results in somewhat
5597    smaller code - although the code savings are not that big (on
5598    average for all boards 752 bytes for the whole U-Boot image,
5599    624 text + 127 data).
5600
5601On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5602	http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5603
5604    ==> U-Boot will use P3 to hold a pointer to the global data
5605
5606On ARM, the following registers are used:
5607
5608	R0:	function argument word/integer result
5609	R1-R3:	function argument word
5610	R9:	platform specific
5611	R10:	stack limit (used only if stack checking is enabled)
5612	R11:	argument (frame) pointer
5613	R12:	temporary workspace
5614	R13:	stack pointer
5615	R14:	link register
5616	R15:	program counter
5617
5618    ==> U-Boot will use R9 to hold a pointer to the global data
5619
5620    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5621
5622On Nios II, the ABI is documented here:
5623	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5624
5625    ==> U-Boot will use gp to hold a pointer to the global data
5626
5627    Note: on Nios II, we give "-G0" option to gcc and don't use gp
5628    to access small data sections, so gp is free.
5629
5630On NDS32, the following registers are used:
5631
5632	R0-R1:	argument/return
5633	R2-R5:	argument
5634	R15:	temporary register for assembler
5635	R16:	trampoline register
5636	R28:	frame pointer (FP)
5637	R29:	global pointer (GP)
5638	R30:	link register (LP)
5639	R31:	stack pointer (SP)
5640	PC:	program counter (PC)
5641
5642    ==> U-Boot will use R10 to hold a pointer to the global data
5643
5644NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5645or current versions of GCC may "optimize" the code too much.
5646
5647Memory Management:
5648------------------
5649
5650U-Boot runs in system state and uses physical addresses, i.e. the
5651MMU is not used either for address mapping nor for memory protection.
5652
5653The available memory is mapped to fixed addresses using the memory
5654controller. In this process, a contiguous block is formed for each
5655memory type (Flash, SDRAM, SRAM), even when it consists of several
5656physical memory banks.
5657
5658U-Boot is installed in the first 128 kB of the first Flash bank (on
5659TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5660booting and sizing and initializing DRAM, the code relocates itself
5661to the upper end of DRAM. Immediately below the U-Boot code some
5662memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5663configuration setting]. Below that, a structure with global Board
5664Info data is placed, followed by the stack (growing downward).
5665
5666Additionally, some exception handler code is copied to the low 8 kB
5667of DRAM (0x00000000 ... 0x00001FFF).
5668
5669So a typical memory configuration with 16 MB of DRAM could look like
5670this:
5671
5672	0x0000 0000	Exception Vector code
5673	      :
5674	0x0000 1FFF
5675	0x0000 2000	Free for Application Use
5676	      :
5677	      :
5678
5679	      :
5680	      :
5681	0x00FB FF20	Monitor Stack (Growing downward)
5682	0x00FB FFAC	Board Info Data and permanent copy of global data
5683	0x00FC 0000	Malloc Arena
5684	      :
5685	0x00FD FFFF
5686	0x00FE 0000	RAM Copy of Monitor Code
5687	...		eventually: LCD or video framebuffer
5688	...		eventually: pRAM (Protected RAM - unchanged by reset)
5689	0x00FF FFFF	[End of RAM]
5690
5691
5692System Initialization:
5693----------------------
5694
5695In the reset configuration, U-Boot starts at the reset entry point
5696(on most PowerPC systems at address 0x00000100). Because of the reset
5697configuration for CS0# this is a mirror of the onboard Flash memory.
5698To be able to re-map memory U-Boot then jumps to its link address.
5699To be able to implement the initialization code in C, a (small!)
5700initial stack is set up in the internal Dual Ported RAM (in case CPUs
5701which provide such a feature like MPC8xx or MPC8260), or in a locked
5702part of the data cache. After that, U-Boot initializes the CPU core,
5703the caches and the SIU.
5704
5705Next, all (potentially) available memory banks are mapped using a
5706preliminary mapping. For example, we put them on 512 MB boundaries
5707(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5708on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5709programmed for SDRAM access. Using the temporary configuration, a
5710simple memory test is run that determines the size of the SDRAM
5711banks.
5712
5713When there is more than one SDRAM bank, and the banks are of
5714different size, the largest is mapped first. For equal size, the first
5715bank (CS2#) is mapped first. The first mapping is always for address
57160x00000000, with any additional banks following immediately to create
5717contiguous memory starting from 0.
5718
5719Then, the monitor installs itself at the upper end of the SDRAM area
5720and allocates memory for use by malloc() and for the global Board
5721Info data; also, the exception vector code is copied to the low RAM
5722pages, and the final stack is set up.
5723
5724Only after this relocation will you have a "normal" C environment;
5725until that you are restricted in several ways, mostly because you are
5726running from ROM, and because the code will have to be relocated to a
5727new address in RAM.
5728
5729
5730U-Boot Porting Guide:
5731----------------------
5732
5733[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5734list, October 2002]
5735
5736
5737int main(int argc, char *argv[])
5738{
5739	sighandler_t no_more_time;
5740
5741	signal(SIGALRM, no_more_time);
5742	alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5743
5744	if (available_money > available_manpower) {
5745		Pay consultant to port U-Boot;
5746		return 0;
5747	}
5748
5749	Download latest U-Boot source;
5750
5751	Subscribe to u-boot mailing list;
5752
5753	if (clueless)
5754		email("Hi, I am new to U-Boot, how do I get started?");
5755
5756	while (learning) {
5757		Read the README file in the top level directory;
5758		Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5759		Read applicable doc/*.README;
5760		Read the source, Luke;
5761		/* find . -name "*.[chS]" | xargs grep -i <keyword> */
5762	}
5763
5764	if (available_money > toLocalCurrency ($2500))
5765		Buy a BDI3000;
5766	else
5767		Add a lot of aggravation and time;
5768
5769	if (a similar board exists) {	/* hopefully... */
5770		cp -a board/<similar> board/<myboard>
5771		cp include/configs/<similar>.h include/configs/<myboard>.h
5772	} else {
5773		Create your own board support subdirectory;
5774		Create your own board include/configs/<myboard>.h file;
5775	}
5776	Edit new board/<myboard> files
5777	Edit new include/configs/<myboard>.h
5778
5779	while (!accepted) {
5780		while (!running) {
5781			do {
5782				Add / modify source code;
5783			} until (compiles);
5784			Debug;
5785			if (clueless)
5786				email("Hi, I am having problems...");
5787		}
5788		Send patch file to the U-Boot email list;
5789		if (reasonable critiques)
5790			Incorporate improvements from email list code review;
5791		else
5792			Defend code as written;
5793	}
5794
5795	return 0;
5796}
5797
5798void no_more_time (int sig)
5799{
5800      hire_a_guru();
5801}
5802
5803
5804Coding Standards:
5805-----------------
5806
5807All contributions to U-Boot should conform to the Linux kernel
5808coding style; see the file "Documentation/CodingStyle" and the script
5809"scripts/Lindent" in your Linux kernel source directory.
5810
5811Source files originating from a different project (for example the
5812MTD subsystem) are generally exempt from these guidelines and are not
5813reformated to ease subsequent migration to newer versions of those
5814sources.
5815
5816Please note that U-Boot is implemented in C (and to some small parts in
5817Assembler); no C++ is used, so please do not use C++ style comments (//)
5818in your code.
5819
5820Please also stick to the following formatting rules:
5821- remove any trailing white space
5822- use TAB characters for indentation and vertical alignment, not spaces
5823- make sure NOT to use DOS '\r\n' line feeds
5824- do not add more than 2 consecutive empty lines to source files
5825- do not add trailing empty lines to source files
5826
5827Submissions which do not conform to the standards may be returned
5828with a request to reformat the changes.
5829
5830
5831Submitting Patches:
5832-------------------
5833
5834Since the number of patches for U-Boot is growing, we need to
5835establish some rules. Submissions which do not conform to these rules
5836may be rejected, even when they contain important and valuable stuff.
5837
5838Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5839
5840Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5841see http://lists.denx.de/mailman/listinfo/u-boot
5842
5843When you send a patch, please include the following information with
5844it:
5845
5846* For bug fixes: a description of the bug and how your patch fixes
5847  this bug. Please try to include a way of demonstrating that the
5848  patch actually fixes something.
5849
5850* For new features: a description of the feature and your
5851  implementation.
5852
5853* A CHANGELOG entry as plaintext (separate from the patch)
5854
5855* For major contributions, your entry to the CREDITS file
5856
5857* When you add support for a new board, don't forget to add a
5858  maintainer e-mail address to the boards.cfg file, too.
5859
5860* If your patch adds new configuration options, don't forget to
5861  document these in the README file.
5862
5863* The patch itself. If you are using git (which is *strongly*
5864  recommended) you can easily generate the patch using the
5865  "git format-patch". If you then use "git send-email" to send it to
5866  the U-Boot mailing list, you will avoid most of the common problems
5867  with some other mail clients.
5868
5869  If you cannot use git, use "diff -purN OLD NEW". If your version of
5870  diff does not support these options, then get the latest version of
5871  GNU diff.
5872
5873  The current directory when running this command shall be the parent
5874  directory of the U-Boot source tree (i. e. please make sure that
5875  your patch includes sufficient directory information for the
5876  affected files).
5877
5878  We prefer patches as plain text. MIME attachments are discouraged,
5879  and compressed attachments must not be used.
5880
5881* If one logical set of modifications affects or creates several
5882  files, all these changes shall be submitted in a SINGLE patch file.
5883
5884* Changesets that contain different, unrelated modifications shall be
5885  submitted as SEPARATE patches, one patch per changeset.
5886
5887
5888Notes:
5889
5890* Before sending the patch, run the MAKEALL script on your patched
5891  source tree and make sure that no errors or warnings are reported
5892  for any of the boards.
5893
5894* Keep your modifications to the necessary minimum: A patch
5895  containing several unrelated changes or arbitrary reformats will be
5896  returned with a request to re-formatting / split it.
5897
5898* If you modify existing code, make sure that your new code does not
5899  add to the memory footprint of the code ;-) Small is beautiful!
5900  When adding new features, these should compile conditionally only
5901  (using #ifdef), and the resulting code with the new feature
5902  disabled must not need more memory than the old code without your
5903  modification.
5904
5905* Remember that there is a size limit of 100 kB per message on the
5906  u-boot mailing list. Bigger patches will be moderated. If they are
5907  reasonable and not too big, they will be acknowledged. But patches
5908  bigger than the size limit should be avoided.
5909