xref: /rk3399_rockchip-uboot/README (revision 6433fa202a91a6594dd48f06807ac38ba27fa0bb)
1#
2# (C) Copyright 2000 - 2008
3# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4#
5# See file CREDITS for list of people who contributed to this
6# project.
7#
8# This program is free software; you can redistribute it and/or
9# modify it under the terms of the GNU General Public License as
10# published by the Free Software Foundation; either version 2 of
11# the License, or (at your option) any later version.
12#
13# This program is distributed in the hope that it will be useful,
14# but WITHOUT ANY WARRANTY; without even the implied warranty of
15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
16# GNU General Public License for more details.
17#
18# You should have received a copy of the GNU General Public License
19# along with this program; if not, write to the Free Software
20# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21# MA 02111-1307 USA
22#
23
24Summary:
25========
26
27This directory contains the source code for U-Boot, a boot loader for
28Embedded boards based on PowerPC, ARM, MIPS and several other
29processors, which can be installed in a boot ROM and used to
30initialize and test the hardware or to download and run application
31code.
32
33The development of U-Boot is closely related to Linux: some parts of
34the source code originate in the Linux source tree, we have some
35header files in common, and special provision has been made to
36support booting of Linux images.
37
38Some attention has been paid to make this software easily
39configurable and extendable. For instance, all monitor commands are
40implemented with the same call interface, so that it's very easy to
41add new commands. Also, instead of permanently adding rarely used
42code (for instance hardware test utilities) to the monitor, you can
43load and run it dynamically.
44
45
46Status:
47=======
48
49In general, all boards for which a configuration option exists in the
50Makefile have been tested to some extent and can be considered
51"working". In fact, many of them are used in production systems.
52
53In case of problems see the CHANGELOG and CREDITS files to find out
54who contributed the specific port. The MAINTAINERS file lists board
55maintainers.
56
57
58Where to get help:
59==================
60
61In case you have questions about, problems with or contributions for
62U-Boot you should send a message to the U-Boot mailing list at
63<u-boot-users@lists.sourceforge.net>. There is also an archive of
64previous traffic on the mailing list - please search the archive
65before asking FAQ's. Please see
66http://lists.sourceforge.net/lists/listinfo/u-boot-users/
67
68
69Where to get source code:
70=========================
71
72The U-Boot source code is maintained in the git repository at
73git://www.denx.de/git/u-boot.git ; you can browse it online at
74http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
75
76The "snapshot" links on this page allow you to download tarballs of
77any version you might be interested in. Ofifcial releases are also
78available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
79directory.
80
81Pre-built (and tested) images are available from
82ftp://ftp.denx.de/pub/u-boot/images/
83
84
85Where we come from:
86===================
87
88- start from 8xxrom sources
89- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
90- clean up code
91- make it easier to add custom boards
92- make it possible to add other [PowerPC] CPUs
93- extend functions, especially:
94  * Provide extended interface to Linux boot loader
95  * S-Record download
96  * network boot
97  * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
98- create ARMBoot project (http://sourceforge.net/projects/armboot)
99- add other CPU families (starting with ARM)
100- create U-Boot project (http://sourceforge.net/projects/u-boot)
101- current project page: see http://www.denx.de/wiki/UBoot
102
103
104Names and Spelling:
105===================
106
107The "official" name of this project is "Das U-Boot". The spelling
108"U-Boot" shall be used in all written text (documentation, comments
109in source files etc.). Example:
110
111	This is the README file for the U-Boot project.
112
113File names etc. shall be based on the string "u-boot". Examples:
114
115	include/asm-ppc/u-boot.h
116
117	#include <asm/u-boot.h>
118
119Variable names, preprocessor constants etc. shall be either based on
120the string "u_boot" or on "U_BOOT". Example:
121
122	U_BOOT_VERSION		u_boot_logo
123	IH_OS_U_BOOT		u_boot_hush_start
124
125
126Versioning:
127===========
128
129U-Boot uses a 3 level version number containing a version, a
130sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131sub-version "34", and patchlevel "4".
132
133The patchlevel is used to indicate certain stages of development
134between released versions, i. e. officially released versions of
135U-Boot will always have a patchlevel of "0".
136
137
138Directory Hierarchy:
139====================
140
141- board		Board dependent files
142- common	Misc architecture independent functions
143- cpu		CPU specific files
144  - 74xx_7xx	Files specific to Freescale MPC74xx and 7xx CPUs
145  - arm720t	Files specific to ARM 720 CPUs
146  - arm920t	Files specific to ARM 920 CPUs
147    - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148    - imx	Files specific to Freescale MC9328 i.MX CPUs
149    - s3c24x0	Files specific to Samsung S3C24X0 CPUs
150  - arm925t	Files specific to ARM 925 CPUs
151  - arm926ejs	Files specific to ARM 926 CPUs
152  - arm1136	Files specific to ARM 1136 CPUs
153  - at32ap	Files specific to Atmel AVR32 AP CPUs
154  - i386	Files specific to i386 CPUs
155  - ixp		Files specific to Intel XScale IXP CPUs
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  - mips	Files specific to MIPS CPUs
162  - mpc5xx	Files specific to Freescale MPC5xx  CPUs
163  - mpc5xxx	Files specific to Freescale MPC5xxx CPUs
164  - mpc8xx	Files specific to Freescale MPC8xx  CPUs
165  - mpc8220	Files specific to Freescale MPC8220 CPUs
166  - mpc824x	Files specific to Freescale MPC824x CPUs
167  - mpc8260	Files specific to Freescale MPC8260 CPUs
168  - mpc85xx	Files specific to Freescale MPC85xx CPUs
169  - nios	Files specific to Altera NIOS CPUs
170  - nios2	Files specific to Altera Nios-II CPUs
171  - ppc4xx	Files specific to AMCC PowerPC 4xx CPUs
172  - pxa		Files specific to Intel XScale PXA CPUs
173  - s3c44b0	Files specific to Samsung S3C44B0 CPUs
174  - sa1100	Files specific to Intel StrongARM SA1100 CPUs
175- disk		Code for disk drive partition handling
176- doc		Documentation (don't expect too much)
177- drivers	Commonly used device drivers
178- dtt		Digital Thermometer and Thermostat drivers
179- examples	Example code for standalone applications, etc.
180- include	Header Files
181- lib_arm	Files generic to ARM	 architecture
182- lib_avr32	Files generic to AVR32	 architecture
183- lib_generic	Files generic to all	 architectures
184- lib_i386	Files generic to i386	 architecture
185- lib_m68k	Files generic to m68k	 architecture
186- lib_mips	Files generic to MIPS	 architecture
187- lib_nios	Files generic to NIOS	 architecture
188- lib_ppc	Files generic to PowerPC architecture
189- libfdt	Library files to support flattened device trees
190- net		Networking code
191- post		Power On Self Test
192- rtc		Real Time Clock drivers
193- tools		Tools to build S-Record or U-Boot images, etc.
194
195Software Configuration:
196=======================
197
198Configuration is usually done using C preprocessor defines; the
199rationale behind that is to avoid dead code whenever possible.
200
201There are two classes of configuration variables:
202
203* Configuration _OPTIONS_:
204  These are selectable by the user and have names beginning with
205  "CONFIG_".
206
207* Configuration _SETTINGS_:
208  These depend on the hardware etc. and should not be meddled with if
209  you don't know what you're doing; they have names beginning with
210  "CFG_".
211
212Later we will add a configuration tool - probably similar to or even
213identical to what's used for the Linux kernel. Right now, we have to
214do the configuration by hand, which means creating some symbolic
215links and editing some configuration files. We use the TQM8xxL boards
216as an example here.
217
218
219Selection of Processor Architecture and Board Type:
220---------------------------------------------------
221
222For all supported boards there are ready-to-use default
223configurations available; just type "make <board_name>_config".
224
225Example: For a TQM823L module type:
226
227	cd u-boot
228	make TQM823L_config
229
230For the Cogent platform, you need to specify the cpu type as well;
231e.g. "make cogent_mpc8xx_config". And also configure the cogent
232directory according to the instructions in cogent/README.
233
234
235Configuration Options:
236----------------------
237
238Configuration depends on the combination of board and CPU type; all
239such information is kept in a configuration file
240"include/configs/<board_name>.h".
241
242Example: For a TQM823L module, all configuration settings are in
243"include/configs/TQM823L.h".
244
245
246Many of the options are named exactly as the corresponding Linux
247kernel configuration options. The intention is to make it easier to
248build a config tool - later.
249
250
251The following options need to be configured:
252
253- CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.
254
255- Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.
256
257- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
258		Define exactly one, e.g. CONFIG_ATSTK1002
259
260- CPU Module Type: (if CONFIG_COGENT is defined)
261		Define exactly one of
262		CONFIG_CMA286_60_OLD
263--- FIXME --- not tested yet:
264		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
265		CONFIG_CMA287_23, CONFIG_CMA287_50
266
267- Motherboard Type: (if CONFIG_COGENT is defined)
268		Define exactly one of
269		CONFIG_CMA101, CONFIG_CMA102
270
271- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
272		Define one or more of
273		CONFIG_CMA302
274
275- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
276		Define one or more of
277		CONFIG_LCD_HEARTBEAT	- update a character position on
278					  the lcd display every second with
279					  a "rotator" |\-/|\-/
280
281- Board flavour: (if CONFIG_MPC8260ADS is defined)
282		CONFIG_ADSTYPE
283		Possible values are:
284			CFG_8260ADS	- original MPC8260ADS
285			CFG_8266ADS	- MPC8266ADS
286			CFG_PQ2FADS	- PQ2FADS-ZU or PQ2FADS-VR
287			CFG_8272ADS	- MPC8272ADS
288
289- MPC824X Family Member (if CONFIG_MPC824X is defined)
290		Define exactly one of
291		CONFIG_MPC8240, CONFIG_MPC8245
292
293- 8xx CPU Options: (if using an MPC8xx cpu)
294		CONFIG_8xx_GCLK_FREQ	- deprecated: CPU clock if
295					  get_gclk_freq() cannot work
296					  e.g. if there is no 32KHz
297					  reference PIT/RTC clock
298		CONFIG_8xx_OSCLK	- PLL input clock (either EXTCLK
299					  or XTAL/EXTAL)
300
301- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
302		CFG_8xx_CPUCLK_MIN
303		CFG_8xx_CPUCLK_MAX
304		CONFIG_8xx_CPUCLK_DEFAULT
305			See doc/README.MPC866
306
307		CFG_MEASURE_CPUCLK
308
309		Define this to measure the actual CPU clock instead
310		of relying on the correctness of the configured
311		values. Mostly useful for board bringup to make sure
312		the PLL is locked at the intended frequency. Note
313		that this requires a (stable) reference clock (32 kHz
314		RTC clock or CFG_8XX_XIN)
315
316- Intel Monahans options:
317		CFG_MONAHANS_RUN_MODE_OSC_RATIO
318
319		Defines the Monahans run mode to oscillator
320		ratio. Valid values are 8, 16, 24, 31. The core
321		frequency is this value multiplied by 13 MHz.
322
323		CFG_MONAHANS_TURBO_RUN_MODE_RATIO
324
325		Defines the Monahans turbo mode to oscillator
326		ratio. Valid values are 1 (default if undefined) and
327		2. The core frequency as calculated above is multiplied
328		by this value.
329
330- Linux Kernel Interface:
331		CONFIG_CLOCKS_IN_MHZ
332
333		U-Boot stores all clock information in Hz
334		internally. For binary compatibility with older Linux
335		kernels (which expect the clocks passed in the
336		bd_info data to be in MHz) the environment variable
337		"clocks_in_mhz" can be defined so that U-Boot
338		converts clock data to MHZ before passing it to the
339		Linux kernel.
340		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
341		"clocks_in_mhz=1" is automatically included in the
342		default environment.
343
344		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]
345
346		When transfering memsize parameter to linux, some versions
347		expect it to be in bytes, others in MB.
348		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
349
350		CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
351
352		New kernel versions are expecting firmware settings to be
353		passed using flattened device trees (based on open firmware
354		concepts).
355
356		CONFIG_OF_LIBFDT
357		 * New libfdt-based support
358		 * Adds the "fdt" command
359		 * The bootm command automatically updates the fdt
360
361		CONFIG_OF_FLAT_TREE
362		 * Deprecated, see CONFIG_OF_LIBFDT
363		 * Original ft_build.c-based support
364		 * Automatically modifies the dft as part of the bootm command
365		 * The environment variable "disable_of", when set,
366		     disables this functionality.
367
368		OF_CPU - The proper name of the cpus node.
369		OF_SOC - The proper name of the soc node.
370		OF_TBCLK - The timebase frequency.
371		OF_STDOUT_PATH - The path to the console device
372
373		boards with QUICC Engines require OF_QE to set UCC mac addresses
374
375		CONFIG_OF_HAS_BD_T
376
377		 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
378		 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
379		     will have a copy of the bd_t.  Space should be
380		     pre-allocated in the dts for the bd_t.
381
382		CONFIG_OF_HAS_UBOOT_ENV
383
384		 * CONFIG_OF_LIBFDT - enables the "fdt env" command
385		 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
386		     will have a copy of u-boot's environment variables
387
388		CONFIG_OF_BOARD_SETUP
389
390		Board code has addition modification that it wants to make
391		to the flat device tree before handing it off to the kernel
392
393		CONFIG_OF_BOOT_CPU
394
395		This define fills in the correct boot cpu in the boot
396		param header, the default value is zero if undefined.
397
398- Serial Ports:
399		CFG_PL010_SERIAL
400
401		Define this if you want support for Amba PrimeCell PL010 UARTs.
402
403		CFG_PL011_SERIAL
404
405		Define this if you want support for Amba PrimeCell PL011 UARTs.
406
407		CONFIG_PL011_CLOCK
408
409		If you have Amba PrimeCell PL011 UARTs, set this variable to
410		the clock speed of the UARTs.
411
412		CONFIG_PL01x_PORTS
413
414		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
415		define this to a list of base addresses for each (supported)
416		port. See e.g. include/configs/versatile.h
417
418
419- Console Interface:
420		Depending on board, define exactly one serial port
421		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
422		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
423		console by defining CONFIG_8xx_CONS_NONE
424
425		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
426		port routines must be defined elsewhere
427		(i.e. serial_init(), serial_getc(), ...)
428
429		CONFIG_CFB_CONSOLE
430		Enables console device for a color framebuffer. Needs following
431		defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
432			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
433						(default big endian)
434			VIDEO_HW_RECTFILL	graphic chip supports
435						rectangle fill
436						(cf. smiLynxEM)
437			VIDEO_HW_BITBLT		graphic chip supports
438						bit-blit (cf. smiLynxEM)
439			VIDEO_VISIBLE_COLS	visible pixel columns
440						(cols=pitch)
441			VIDEO_VISIBLE_ROWS	visible pixel rows
442			VIDEO_PIXEL_SIZE	bytes per pixel
443			VIDEO_DATA_FORMAT	graphic data format
444						(0-5, cf. cfb_console.c)
445			VIDEO_FB_ADRS		framebuffer address
446			VIDEO_KBD_INIT_FCT	keyboard int fct
447						(i.e. i8042_kbd_init())
448			VIDEO_TSTC_FCT		test char fct
449						(i.e. i8042_tstc)
450			VIDEO_GETC_FCT		get char fct
451						(i.e. i8042_getc)
452			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
453						(requires blink timer
454						cf. i8042.c)
455			CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
456			CONFIG_CONSOLE_TIME	display time/date info in
457						upper right corner
458						(requires CONFIG_CMD_DATE)
459			CONFIG_VIDEO_LOGO	display Linux logo in
460						upper left corner
461			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
462						linux_logo.h for logo.
463						Requires CONFIG_VIDEO_LOGO
464			CONFIG_CONSOLE_EXTRA_INFO
465						addional board info beside
466						the logo
467
468		When CONFIG_CFB_CONSOLE is defined, video console is
469		default i/o. Serial console can be forced with
470		environment 'console=serial'.
471
472		When CONFIG_SILENT_CONSOLE is defined, all console
473		messages (by U-Boot and Linux!) can be silenced with
474		the "silent" environment variable. See
475		doc/README.silent for more information.
476
477- Console Baudrate:
478		CONFIG_BAUDRATE - in bps
479		Select one of the baudrates listed in
480		CFG_BAUDRATE_TABLE, see below.
481		CFG_BRGCLK_PRESCALE, baudrate prescale
482
483- Interrupt driven serial port input:
484		CONFIG_SERIAL_SOFTWARE_FIFO
485
486		PPC405GP only.
487		Use an interrupt handler for receiving data on the
488		serial port. It also enables using hardware handshake
489		(RTS/CTS) and UART's built-in FIFO. Set the number of
490		bytes the interrupt driven input buffer should have.
491
492		Leave undefined to disable this feature, including
493		disable the buffer and hardware handshake.
494
495- Console UART Number:
496		CONFIG_UART1_CONSOLE
497
498		AMCC PPC4xx only.
499		If defined internal UART1 (and not UART0) is used
500		as default U-Boot console.
501
502- Boot Delay:	CONFIG_BOOTDELAY - in seconds
503		Delay before automatically booting the default image;
504		set to -1 to disable autoboot.
505
506		See doc/README.autoboot for these options that
507		work with CONFIG_BOOTDELAY. None are required.
508		CONFIG_BOOT_RETRY_TIME
509		CONFIG_BOOT_RETRY_MIN
510		CONFIG_AUTOBOOT_KEYED
511		CONFIG_AUTOBOOT_PROMPT
512		CONFIG_AUTOBOOT_DELAY_STR
513		CONFIG_AUTOBOOT_STOP_STR
514		CONFIG_AUTOBOOT_DELAY_STR2
515		CONFIG_AUTOBOOT_STOP_STR2
516		CONFIG_ZERO_BOOTDELAY_CHECK
517		CONFIG_RESET_TO_RETRY
518
519- Autoboot Command:
520		CONFIG_BOOTCOMMAND
521		Only needed when CONFIG_BOOTDELAY is enabled;
522		define a command string that is automatically executed
523		when no character is read on the console interface
524		within "Boot Delay" after reset.
525
526		CONFIG_BOOTARGS
527		This can be used to pass arguments to the bootm
528		command. The value of CONFIG_BOOTARGS goes into the
529		environment value "bootargs".
530
531		CONFIG_RAMBOOT and CONFIG_NFSBOOT
532		The value of these goes into the environment as
533		"ramboot" and "nfsboot" respectively, and can be used
534		as a convenience, when switching between booting from
535		ram and nfs.
536
537- Pre-Boot Commands:
538		CONFIG_PREBOOT
539
540		When this option is #defined, the existence of the
541		environment variable "preboot" will be checked
542		immediately before starting the CONFIG_BOOTDELAY
543		countdown and/or running the auto-boot command resp.
544		entering interactive mode.
545
546		This feature is especially useful when "preboot" is
547		automatically generated or modified. For an example
548		see the LWMON board specific code: here "preboot" is
549		modified when the user holds down a certain
550		combination of keys on the (special) keyboard when
551		booting the systems
552
553- Serial Download Echo Mode:
554		CONFIG_LOADS_ECHO
555		If defined to 1, all characters received during a
556		serial download (using the "loads" command) are
557		echoed back. This might be needed by some terminal
558		emulations (like "cu"), but may as well just take
559		time on others. This setting #define's the initial
560		value of the "loads_echo" environment variable.
561
562- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
563		CONFIG_KGDB_BAUDRATE
564		Select one of the baudrates listed in
565		CFG_BAUDRATE_TABLE, see below.
566
567- Monitor Functions:
568		Monitor commands can be included or excluded
569		from the build by using the #include files
570		"config_cmd_all.h" and #undef'ing unwanted
571		commands, or using "config_cmd_default.h"
572		and augmenting with additional #define's
573		for wanted commands.
574
575		The default command configuration includes all commands
576		except those marked below with a "*".
577
578		CONFIG_CMD_ASKENV	* ask for env variable
579		CONFIG_CMD_AUTOSCRIPT	  Autoscript Support
580		CONFIG_CMD_BDI		  bdinfo
581		CONFIG_CMD_BEDBUG	* Include BedBug Debugger
582		CONFIG_CMD_BMP		* BMP support
583		CONFIG_CMD_BSP		* Board specific commands
584		CONFIG_CMD_BOOTD	  bootd
585		CONFIG_CMD_CACHE	* icache, dcache
586		CONFIG_CMD_CONSOLE	  coninfo
587		CONFIG_CMD_DATE		* support for RTC, date/time...
588		CONFIG_CMD_DHCP		* DHCP support
589		CONFIG_CMD_DIAG		* Diagnostics
590		CONFIG_CMD_DOC		* Disk-On-Chip Support
591		CONFIG_CMD_DTT		* Digital Therm and Thermostat
592		CONFIG_CMD_ECHO		  echo arguments
593		CONFIG_CMD_EEPROM	* EEPROM read/write support
594		CONFIG_CMD_ELF		* bootelf, bootvx
595		CONFIG_CMD_ENV		  saveenv
596		CONFIG_CMD_FDC		* Floppy Disk Support
597		CONFIG_CMD_FAT		* FAT partition support
598		CONFIG_CMD_FDOS		* Dos diskette Support
599		CONFIG_CMD_FLASH	  flinfo, erase, protect
600		CONFIG_CMD_FPGA		  FPGA device initialization support
601		CONFIG_CMD_HWFLOW	* RTS/CTS hw flow control
602		CONFIG_CMD_I2C		* I2C serial bus support
603		CONFIG_CMD_IDE		* IDE harddisk support
604		CONFIG_CMD_IMI		  iminfo
605		CONFIG_CMD_IMLS		  List all found images
606		CONFIG_CMD_IMMAP	* IMMR dump support
607		CONFIG_CMD_IRQ		* irqinfo
608		CONFIG_CMD_ITEST	  Integer/string test of 2 values
609		CONFIG_CMD_JFFS2	* JFFS2 Support
610		CONFIG_CMD_KGDB		* kgdb
611		CONFIG_CMD_LOADB	  loadb
612		CONFIG_CMD_LOADS	  loads
613		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
614					  loop, loopw, mtest
615		CONFIG_CMD_MISC		  Misc functions like sleep etc
616		CONFIG_CMD_MMC		* MMC memory mapped support
617		CONFIG_CMD_MII		* MII utility commands
618		CONFIG_CMD_NAND		* NAND support
619		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
620		CONFIG_CMD_PCI		* pciinfo
621		CONFIG_CMD_PCMCIA		* PCMCIA support
622		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
623					  host
624		CONFIG_CMD_PORTIO	* Port I/O
625		CONFIG_CMD_REGINFO	* Register dump
626		CONFIG_CMD_RUN		  run command in env variable
627		CONFIG_CMD_SAVES	* save S record dump
628		CONFIG_CMD_SCSI		* SCSI Support
629		CONFIG_CMD_SDRAM	* print SDRAM configuration information
630					  (requires CONFIG_CMD_I2C)
631		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
632					  (4xx only)
633		CONFIG_CMD_SPI		* SPI serial bus support
634		CONFIG_CMD_USB		* USB support
635		CONFIG_CMD_VFD		* VFD support (TRAB)
636		CONFIG_CMD_BSP		* Board SPecific functions
637		CONFIG_CMD_CDP		* Cisco Discover Protocol support
638		CONFIG_CMD_FSL		* Microblaze FSL support
639
640
641		EXAMPLE: If you want all functions except of network
642		support you can write:
643
644		#include "config_cmd_all.h"
645		#undef CONFIG_CMD_NET
646
647	Other Commands:
648		fdt (flattened device tree) command: CONFIG_OF_LIBFDT
649
650	Note:	Don't enable the "icache" and "dcache" commands
651		(configuration option CONFIG_CMD_CACHE) unless you know
652		what you (and your U-Boot users) are doing. Data
653		cache cannot be enabled on systems like the 8xx or
654		8260 (where accesses to the IMMR region must be
655		uncached), and it cannot be disabled on all other
656		systems where we (mis-) use the data cache to hold an
657		initial stack and some data.
658
659
660		XXX - this list needs to get updated!
661
662- Watchdog:
663		CONFIG_WATCHDOG
664		If this variable is defined, it enables watchdog
665		support. There must be support in the platform specific
666		code for a watchdog. For the 8xx and 8260 CPUs, the
667		SIU Watchdog feature is enabled in the SYPCR
668		register.
669
670- U-Boot Version:
671		CONFIG_VERSION_VARIABLE
672		If this variable is defined, an environment variable
673		named "ver" is created by U-Boot showing the U-Boot
674		version as printed by the "version" command.
675		This variable is readonly.
676
677- Real-Time Clock:
678
679		When CONFIG_CMD_DATE is selected, the type of the RTC
680		has to be selected, too. Define exactly one of the
681		following options:
682
683		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
684		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
685		CONFIG_RTC_MC146818	- use MC146818 RTC
686		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
687		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
688		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
689		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
690		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
691		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
692		CFG_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
693
694		Note that if the RTC uses I2C, then the I2C interface
695		must also be configured. See I2C Support, below.
696
697- Timestamp Support:
698
699		When CONFIG_TIMESTAMP is selected, the timestamp
700		(date and time) of an image is printed by image
701		commands like bootm or iminfo. This option is
702		automatically enabled when you select CONFIG_CMD_DATE .
703
704- Partition Support:
705		CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
706		and/or CONFIG_ISO_PARTITION
707
708		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
709		CONFIG_CMD_SCSI) you must configure support for at
710		least one partition type as well.
711
712- IDE Reset method:
713		CONFIG_IDE_RESET_ROUTINE - this is defined in several
714		board configurations files but used nowhere!
715
716		CONFIG_IDE_RESET - is this is defined, IDE Reset will
717		be performed by calling the function
718			ide_set_reset(int reset)
719		which has to be defined in a board specific file
720
721- ATAPI Support:
722		CONFIG_ATAPI
723
724		Set this to enable ATAPI support.
725
726- LBA48 Support
727		CONFIG_LBA48
728
729		Set this to enable support for disks larger than 137GB
730		Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
731		Whithout these , LBA48 support uses 32bit variables and will 'only'
732		support disks up to 2.1TB.
733
734		CFG_64BIT_LBA:
735			When enabled, makes the IDE subsystem use 64bit sector addresses.
736			Default is 32bit.
737
738- SCSI Support:
739		At the moment only there is only support for the
740		SYM53C8XX SCSI controller; define
741		CONFIG_SCSI_SYM53C8XX to enable it.
742
743		CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
744		CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
745		CFG_SCSI_MAX_LUN] can be adjusted to define the
746		maximum numbers of LUNs, SCSI ID's and target
747		devices.
748		CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
749
750- NETWORK Support (PCI):
751		CONFIG_E1000
752		Support for Intel 8254x gigabit chips.
753
754		CONFIG_EEPRO100
755		Support for Intel 82557/82559/82559ER chips.
756		Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
757		write routine for first time initialisation.
758
759		CONFIG_TULIP
760		Support for Digital 2114x chips.
761		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
762		modem chip initialisation (KS8761/QS6611).
763
764		CONFIG_NATSEMI
765		Support for National dp83815 chips.
766
767		CONFIG_NS8382X
768		Support for National dp8382[01] gigabit chips.
769
770- NETWORK Support (other):
771
772		CONFIG_DRIVER_LAN91C96
773		Support for SMSC's LAN91C96 chips.
774
775			CONFIG_LAN91C96_BASE
776			Define this to hold the physical address
777			of the LAN91C96's I/O space
778
779			CONFIG_LAN91C96_USE_32_BIT
780			Define this to enable 32 bit addressing
781
782		CONFIG_DRIVER_SMC91111
783		Support for SMSC's LAN91C111 chip
784
785			CONFIG_SMC91111_BASE
786			Define this to hold the physical address
787			of the device (I/O space)
788
789			CONFIG_SMC_USE_32_BIT
790			Define this if data bus is 32 bits
791
792			CONFIG_SMC_USE_IOFUNCS
793			Define this to use i/o functions instead of macros
794			(some hardware wont work with macros)
795
796- USB Support:
797		At the moment only the UHCI host controller is
798		supported (PIP405, MIP405, MPC5200); define
799		CONFIG_USB_UHCI to enable it.
800		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
801		and define CONFIG_USB_STORAGE to enable the USB
802		storage devices.
803		Note:
804		Supported are USB Keyboards and USB Floppy drives
805		(TEAC FD-05PUB).
806		MPC5200 USB requires additional defines:
807			CONFIG_USB_CLOCK
808				for 528 MHz Clock: 0x0001bbbb
809			CONFIG_USB_CONFIG
810				for differential drivers: 0x00001000
811				for single ended drivers: 0x00005000
812			CFG_USB_EVENT_POLL
813				May be defined to allow interrupt polling
814				instead of using asynchronous interrupts
815
816- USB Device:
817		Define the below if you wish to use the USB console.
818		Once firmware is rebuilt from a serial console issue the
819		command "setenv stdin usbtty; setenv stdout usbtty" and
820		attach your usb cable. The Unix command "dmesg" should print
821		it has found a new device. The environment variable usbtty
822		can be set to gserial or cdc_acm to enable your device to
823		appear to a USB host as a Linux gserial device or a
824		Common Device Class Abstract Control Model serial device.
825		If you select usbtty = gserial you should be able to enumerate
826		a Linux host by
827		# modprobe usbserial vendor=0xVendorID product=0xProductID
828		else if using cdc_acm, simply setting the environment
829		variable usbtty to be cdc_acm should suffice. The following
830		might be defined in YourBoardName.h
831
832			CONFIG_USB_DEVICE
833			Define this to build a UDC device
834
835			CONFIG_USB_TTY
836			Define this to have a tty type of device available to
837			talk to the UDC device
838
839			CFG_CONSOLE_IS_IN_ENV
840			Define this if you want stdin, stdout &/or stderr to
841			be set to usbtty.
842
843			mpc8xx:
844				CFG_USB_EXTC_CLK 0xBLAH
845				Derive USB clock from external clock "blah"
846				- CFG_USB_EXTC_CLK 0x02
847
848				CFG_USB_BRG_CLK 0xBLAH
849				Derive USB clock from brgclk
850				- CFG_USB_BRG_CLK 0x04
851
852		If you have a USB-IF assigned VendorID then you may wish to
853		define your own vendor specific values either in BoardName.h
854		or directly in usbd_vendor_info.h. If you don't define
855		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
856		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
857		should pretend to be a Linux device to it's target host.
858
859			CONFIG_USBD_MANUFACTURER
860			Define this string as the name of your company for
861			- CONFIG_USBD_MANUFACTURER "my company"
862
863			CONFIG_USBD_PRODUCT_NAME
864			Define this string as the name of your product
865			- CONFIG_USBD_PRODUCT_NAME "acme usb device"
866
867			CONFIG_USBD_VENDORID
868			Define this as your assigned Vendor ID from the USB
869			Implementors Forum. This *must* be a genuine Vendor ID
870			to avoid polluting the USB namespace.
871			- CONFIG_USBD_VENDORID 0xFFFF
872
873			CONFIG_USBD_PRODUCTID
874			Define this as the unique Product ID
875			for your device
876			- CONFIG_USBD_PRODUCTID 0xFFFF
877
878
879- MMC Support:
880		The MMC controller on the Intel PXA is supported. To
881		enable this define CONFIG_MMC. The MMC can be
882		accessed from the boot prompt by mapping the device
883		to physical memory similar to flash. Command line is
884		enabled with CONFIG_CMD_MMC. The MMC driver also works with
885		the FAT fs. This is enabled with CONFIG_CMD_FAT.
886
887- Journaling Flash filesystem support:
888		CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
889		CONFIG_JFFS2_NAND_DEV
890		Define these for a default partition on a NAND device
891
892		CFG_JFFS2_FIRST_SECTOR,
893		CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
894		Define these for a default partition on a NOR device
895
896		CFG_JFFS_CUSTOM_PART
897		Define this to create an own partition. You have to provide a
898		function struct part_info* jffs2_part_info(int part_num)
899
900		If you define only one JFFS2 partition you may also want to
901		#define CFG_JFFS_SINGLE_PART	1
902		to disable the command chpart. This is the default when you
903		have not defined a custom partition
904
905- Keyboard Support:
906		CONFIG_ISA_KEYBOARD
907
908		Define this to enable standard (PC-Style) keyboard
909		support
910
911		CONFIG_I8042_KBD
912		Standard PC keyboard driver with US (is default) and
913		GERMAN key layout (switch via environment 'keymap=de') support.
914		Export function i8042_kbd_init, i8042_tstc and i8042_getc
915		for cfb_console. Supports cursor blinking.
916
917- Video support:
918		CONFIG_VIDEO
919
920		Define this to enable video support (for output to
921		video).
922
923		CONFIG_VIDEO_CT69000
924
925		Enable Chips & Technologies 69000 Video chip
926
927		CONFIG_VIDEO_SMI_LYNXEM
928		Enable Silicon Motion SMI 712/710/810 Video chip. The
929		video output is selected via environment 'videoout'
930		(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
931		assumed.
932
933		For the CT69000 and SMI_LYNXEM drivers, videomode is
934		selected via environment 'videomode'. Two diferent ways
935		are possible:
936		- "videomode=num"   'num' is a standard LiLo mode numbers.
937		Following standard modes are supported	(* is default):
938
939		      Colors	640x480 800x600 1024x768 1152x864 1280x1024
940		-------------+---------------------------------------------
941		      8 bits |	0x301*	0x303	 0x305	  0x161	    0x307
942		     15 bits |	0x310	0x313	 0x316	  0x162	    0x319
943		     16 bits |	0x311	0x314	 0x317	  0x163	    0x31A
944		     24 bits |	0x312	0x315	 0x318	    ?	    0x31B
945		-------------+---------------------------------------------
946		(i.e. setenv videomode 317; saveenv; reset;)
947
948		- "videomode=bootargs" all the video parameters are parsed
949		from the bootargs. (See drivers/video/videomodes.c)
950
951
952		CONFIG_VIDEO_SED13806
953		Enable Epson SED13806 driver. This driver supports 8bpp
954		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
955		or CONFIG_VIDEO_SED13806_16BPP
956
957- Keyboard Support:
958		CONFIG_KEYBOARD
959
960		Define this to enable a custom keyboard support.
961		This simply calls drv_keyboard_init() which must be
962		defined in your board-specific files.
963		The only board using this so far is RBC823.
964
965- LCD Support:	CONFIG_LCD
966
967		Define this to enable LCD support (for output to LCD
968		display); also select one of the supported displays
969		by defining one of these:
970
971		CONFIG_NEC_NL6448AC33:
972
973			NEC NL6448AC33-18. Active, color, single scan.
974
975		CONFIG_NEC_NL6448BC20
976
977			NEC NL6448BC20-08. 6.5", 640x480.
978			Active, color, single scan.
979
980		CONFIG_NEC_NL6448BC33_54
981
982			NEC NL6448BC33-54. 10.4", 640x480.
983			Active, color, single scan.
984
985		CONFIG_SHARP_16x9
986
987			Sharp 320x240. Active, color, single scan.
988			It isn't 16x9, and I am not sure what it is.
989
990		CONFIG_SHARP_LQ64D341
991
992			Sharp LQ64D341 display, 640x480.
993			Active, color, single scan.
994
995		CONFIG_HLD1045
996
997			HLD1045 display, 640x480.
998			Active, color, single scan.
999
1000		CONFIG_OPTREX_BW
1001
1002			Optrex	 CBL50840-2 NF-FW 99 22 M5
1003			or
1004			Hitachi	 LMG6912RPFC-00T
1005			or
1006			Hitachi	 SP14Q002
1007
1008			320x240. Black & white.
1009
1010		Normally display is black on white background; define
1011		CFG_WHITE_ON_BLACK to get it inverted.
1012
1013- Splash Screen Support: CONFIG_SPLASH_SCREEN
1014
1015		If this option is set, the environment is checked for
1016		a variable "splashimage". If found, the usual display
1017		of logo, copyright and system information on the LCD
1018		is suppressed and the BMP image at the address
1019		specified in "splashimage" is loaded instead. The
1020		console is redirected to the "nulldev", too. This
1021		allows for a "silent" boot where a splash screen is
1022		loaded very quickly after power-on.
1023
1024- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1025
1026		If this option is set, additionally to standard BMP
1027		images, gzipped BMP images can be displayed via the
1028		splashscreen support or the bmp command.
1029
1030- Compression support:
1031		CONFIG_BZIP2
1032
1033		If this option is set, support for bzip2 compressed
1034		images is included. If not, only uncompressed and gzip
1035		compressed images are supported.
1036
1037		NOTE: the bzip2 algorithm requires a lot of RAM, so
1038		the malloc area (as defined by CFG_MALLOC_LEN) should
1039		be at least 4MB.
1040
1041- MII/PHY support:
1042		CONFIG_PHY_ADDR
1043
1044		The address of PHY on MII bus.
1045
1046		CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1047
1048		The clock frequency of the MII bus
1049
1050		CONFIG_PHY_GIGE
1051
1052		If this option is set, support for speed/duplex
1053		detection of Gigabit PHY is included.
1054
1055		CONFIG_PHY_RESET_DELAY
1056
1057		Some PHY like Intel LXT971A need extra delay after
1058		reset before any MII register access is possible.
1059		For such PHY, set this option to the usec delay
1060		required. (minimum 300usec for LXT971A)
1061
1062		CONFIG_PHY_CMD_DELAY (ppc4xx)
1063
1064		Some PHY like Intel LXT971A need extra delay after
1065		command issued before MII status register can be read
1066
1067- Ethernet address:
1068		CONFIG_ETHADDR
1069		CONFIG_ETH2ADDR
1070		CONFIG_ETH3ADDR
1071
1072		Define a default value for ethernet address to use
1073		for the respective ethernet interface, in case this
1074		is not determined automatically.
1075
1076- IP address:
1077		CONFIG_IPADDR
1078
1079		Define a default value for the IP address to use for
1080		the default ethernet interface, in case this is not
1081		determined through e.g. bootp.
1082
1083- Server IP address:
1084		CONFIG_SERVERIP
1085
1086		Defines a default value for theIP address of a TFTP
1087		server to contact when using the "tftboot" command.
1088
1089- Multicast TFTP Mode:
1090		CONFIG_MCAST_TFTP
1091
1092		Defines whether you want to support multicast TFTP as per
1093		rfc-2090; for example to work with atftp.  Lets lots of targets
1094		tftp down the same boot image concurrently.  Note: the ethernet
1095		driver in use must provide a function: mcast() to join/leave a
1096		multicast group.
1097
1098		CONFIG_BOOTP_RANDOM_DELAY
1099- BOOTP Recovery Mode:
1100		CONFIG_BOOTP_RANDOM_DELAY
1101
1102		If you have many targets in a network that try to
1103		boot using BOOTP, you may want to avoid that all
1104		systems send out BOOTP requests at precisely the same
1105		moment (which would happen for instance at recovery
1106		from a power failure, when all systems will try to
1107		boot, thus flooding the BOOTP server. Defining
1108		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1109		inserted before sending out BOOTP requests. The
1110		following delays are inserted then:
1111
1112		1st BOOTP request:	delay 0 ... 1 sec
1113		2nd BOOTP request:	delay 0 ... 2 sec
1114		3rd BOOTP request:	delay 0 ... 4 sec
1115		4th and following
1116		BOOTP requests:		delay 0 ... 8 sec
1117
1118- DHCP Advanced Options:
1119		You can fine tune the DHCP functionality by defining
1120		CONFIG_BOOTP_* symbols:
1121
1122		CONFIG_BOOTP_SUBNETMASK
1123		CONFIG_BOOTP_GATEWAY
1124		CONFIG_BOOTP_HOSTNAME
1125		CONFIG_BOOTP_NISDOMAIN
1126		CONFIG_BOOTP_BOOTPATH
1127		CONFIG_BOOTP_BOOTFILESIZE
1128		CONFIG_BOOTP_DNS
1129		CONFIG_BOOTP_DNS2
1130		CONFIG_BOOTP_SEND_HOSTNAME
1131		CONFIG_BOOTP_NTPSERVER
1132		CONFIG_BOOTP_TIMEOFFSET
1133		CONFIG_BOOTP_VENDOREX
1134
1135		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1136		environment variable, not the BOOTP server.
1137
1138		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1139		serverip from a DHCP server, it is possible that more
1140		than one DNS serverip is offered to the client.
1141		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1142		serverip will be stored in the additional environment
1143		variable "dnsip2". The first DNS serverip is always
1144		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1145		is defined.
1146
1147		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1148		to do a dynamic update of a DNS server. To do this, they
1149		need the hostname of the DHCP requester.
1150		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1151		of the "hostname" environment variable is passed as
1152		option 12 to the DHCP server.
1153
1154 - CDP Options:
1155		CONFIG_CDP_DEVICE_ID
1156
1157		The device id used in CDP trigger frames.
1158
1159		CONFIG_CDP_DEVICE_ID_PREFIX
1160
1161		A two character string which is prefixed to the MAC address
1162		of the device.
1163
1164		CONFIG_CDP_PORT_ID
1165
1166		A printf format string which contains the ascii name of
1167		the port. Normally is set to "eth%d" which sets
1168		eth0 for the first ethernet, eth1 for the second etc.
1169
1170		CONFIG_CDP_CAPABILITIES
1171
1172		A 32bit integer which indicates the device capabilities;
1173		0x00000010 for a normal host which does not forwards.
1174
1175		CONFIG_CDP_VERSION
1176
1177		An ascii string containing the version of the software.
1178
1179		CONFIG_CDP_PLATFORM
1180
1181		An ascii string containing the name of the platform.
1182
1183		CONFIG_CDP_TRIGGER
1184
1185		A 32bit integer sent on the trigger.
1186
1187		CONFIG_CDP_POWER_CONSUMPTION
1188
1189		A 16bit integer containing the power consumption of the
1190		device in .1 of milliwatts.
1191
1192		CONFIG_CDP_APPLIANCE_VLAN_TYPE
1193
1194		A byte containing the id of the VLAN.
1195
1196- Status LED:	CONFIG_STATUS_LED
1197
1198		Several configurations allow to display the current
1199		status using a LED. For instance, the LED will blink
1200		fast while running U-Boot code, stop blinking as
1201		soon as a reply to a BOOTP request was received, and
1202		start blinking slow once the Linux kernel is running
1203		(supported by a status LED driver in the Linux
1204		kernel). Defining CONFIG_STATUS_LED enables this
1205		feature in U-Boot.
1206
1207- CAN Support:	CONFIG_CAN_DRIVER
1208
1209		Defining CONFIG_CAN_DRIVER enables CAN driver support
1210		on those systems that support this (optional)
1211		feature, like the TQM8xxL modules.
1212
1213- I2C Support:	CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1214
1215		These enable I2C serial bus commands. Defining either of
1216		(but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1217		include the appropriate I2C driver for the selected cpu.
1218
1219		This will allow you to use i2c commands at the u-boot
1220		command line (as long as you set CONFIG_CMD_I2C in
1221		CONFIG_COMMANDS) and communicate with i2c based realtime
1222		clock chips. See common/cmd_i2c.c for a description of the
1223		command line interface.
1224
1225		CONFIG_I2C_CMD_TREE is a recommended option that places
1226		all I2C commands under a single 'i2c' root command.  The
1227		older 'imm', 'imd', 'iprobe' etc. commands are considered
1228		deprecated and may disappear in the future.
1229
1230		CONFIG_HARD_I2C selects a hardware I2C controller.
1231
1232		CONFIG_SOFT_I2C configures u-boot to use a software (aka
1233		bit-banging) driver instead of CPM or similar hardware
1234		support for I2C.
1235
1236		There are several other quantities that must also be
1237		defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1238
1239		In both cases you will need to define CFG_I2C_SPEED
1240		to be the frequency (in Hz) at which you wish your i2c bus
1241		to run and CFG_I2C_SLAVE to be the address of this node (ie
1242		the cpu's i2c node address).
1243
1244		Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1245		sets the cpu up as a master node and so its address should
1246		therefore be cleared to 0 (See, eg, MPC823e User's Manual
1247		p.16-473). So, set CFG_I2C_SLAVE to 0.
1248
1249		That's all that's required for CONFIG_HARD_I2C.
1250
1251		If you use the software i2c interface (CONFIG_SOFT_I2C)
1252		then the following macros need to be defined (examples are
1253		from include/configs/lwmon.h):
1254
1255		I2C_INIT
1256
1257		(Optional). Any commands necessary to enable the I2C
1258		controller or configure ports.
1259
1260		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)
1261
1262		I2C_PORT
1263
1264		(Only for MPC8260 CPU). The I/O port to use (the code
1265		assumes both bits are on the same port). Valid values
1266		are 0..3 for ports A..D.
1267
1268		I2C_ACTIVE
1269
1270		The code necessary to make the I2C data line active
1271		(driven).  If the data line is open collector, this
1272		define can be null.
1273
1274		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
1275
1276		I2C_TRISTATE
1277
1278		The code necessary to make the I2C data line tri-stated
1279		(inactive).  If the data line is open collector, this
1280		define can be null.
1281
1282		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1283
1284		I2C_READ
1285
1286		Code that returns TRUE if the I2C data line is high,
1287		FALSE if it is low.
1288
1289		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1290
1291		I2C_SDA(bit)
1292
1293		If <bit> is TRUE, sets the I2C data line high. If it
1294		is FALSE, it clears it (low).
1295
1296		eg: #define I2C_SDA(bit) \
1297			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
1298			else	immr->im_cpm.cp_pbdat &= ~PB_SDA
1299
1300		I2C_SCL(bit)
1301
1302		If <bit> is TRUE, sets the I2C clock line high. If it
1303		is FALSE, it clears it (low).
1304
1305		eg: #define I2C_SCL(bit) \
1306			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
1307			else	immr->im_cpm.cp_pbdat &= ~PB_SCL
1308
1309		I2C_DELAY
1310
1311		This delay is invoked four times per clock cycle so this
1312		controls the rate of data transfer.  The data rate thus
1313		is 1 / (I2C_DELAY * 4). Often defined to be something
1314		like:
1315
1316		#define I2C_DELAY  udelay(2)
1317
1318		CFG_I2C_INIT_BOARD
1319
1320		When a board is reset during an i2c bus transfer
1321		chips might think that the current transfer is still
1322		in progress. On some boards it is possible to access
1323		the i2c SCLK line directly, either by using the
1324		processor pin as a GPIO or by having a second pin
1325		connected to the bus. If this option is defined a
1326		custom i2c_init_board() routine in boards/xxx/board.c
1327		is run early in the boot sequence.
1328
1329		CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1330
1331		This option enables configuration of bi_iic_fast[] flags
1332		in u-boot bd_info structure based on u-boot environment
1333		variable "i2cfast". (see also i2cfast)
1334
1335		CONFIG_I2C_MULTI_BUS
1336
1337		This option allows the use of multiple I2C buses, each of which
1338		must have a controller.  At any point in time, only one bus is
1339		active.  To switch to a different bus, use the 'i2c dev' command.
1340		Note that bus numbering is zero-based.
1341
1342		CFG_I2C_NOPROBES
1343
1344		This option specifies a list of I2C devices that will be skipped
1345		when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1346		command).  If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1347		pairs.	Otherwise, specify a 1D array of device addresses
1348
1349		e.g.
1350			#undef	CONFIG_I2C_MULTI_BUS
1351			#define CFG_I2C_NOPROBES	{0x50,0x68}
1352
1353		will skip addresses 0x50 and 0x68 on a board with one I2C bus
1354
1355			#define	CONFIG_I2C_MULTI_BUS
1356			#define CFG_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
1357
1358		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1359
1360		CFG_SPD_BUS_NUM
1361
1362		If defined, then this indicates the I2C bus number for DDR SPD.
1363		If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1364
1365		CFG_RTC_BUS_NUM
1366
1367		If defined, then this indicates the I2C bus number for the RTC.
1368		If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1369
1370		CFG_DTT_BUS_NUM
1371
1372		If defined, then this indicates the I2C bus number for the DTT.
1373		If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1374
1375		CONFIG_FSL_I2C
1376
1377		Define this option if you want to use Freescale's I2C driver in
1378		drivers/i2c/fsl_i2c.c.
1379
1380
1381- SPI Support:	CONFIG_SPI
1382
1383		Enables SPI driver (so far only tested with
1384		SPI EEPROM, also an instance works with Crystal A/D and
1385		D/As on the SACSng board)
1386
1387		CONFIG_SPI_X
1388
1389		Enables extended (16-bit) SPI EEPROM addressing.
1390		(symmetrical to CONFIG_I2C_X)
1391
1392		CONFIG_SOFT_SPI
1393
1394		Enables a software (bit-bang) SPI driver rather than
1395		using hardware support. This is a general purpose
1396		driver that only requires three general I/O port pins
1397		(two outputs, one input) to function. If this is
1398		defined, the board configuration must define several
1399		SPI configuration items (port pins to use, etc). For
1400		an example, see include/configs/sacsng.h.
1401
1402		CONFIG_HARD_SPI
1403
1404		Enables a hardware SPI driver for general-purpose reads
1405		and writes.  As with CONFIG_SOFT_SPI, the board configuration
1406		must define a list of chip-select function pointers.
1407		Currently supported on some MPC8xxx processors.  For an
1408		example, see include/configs/mpc8349emds.h.
1409
1410- FPGA Support: CONFIG_FPGA
1411
1412		Enables FPGA subsystem.
1413
1414		CONFIG_FPGA_<vendor>
1415
1416		Enables support for specific chip vendors.
1417		(ALTERA, XILINX)
1418
1419		CONFIG_FPGA_<family>
1420
1421		Enables support for FPGA family.
1422		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1423
1424		CONFIG_FPGA_COUNT
1425
1426		Specify the number of FPGA devices to support.
1427
1428		CFG_FPGA_PROG_FEEDBACK
1429
1430		Enable printing of hash marks during FPGA configuration.
1431
1432		CFG_FPGA_CHECK_BUSY
1433
1434		Enable checks on FPGA configuration interface busy
1435		status by the configuration function. This option
1436		will require a board or device specific function to
1437		be written.
1438
1439		CONFIG_FPGA_DELAY
1440
1441		If defined, a function that provides delays in the FPGA
1442		configuration driver.
1443
1444		CFG_FPGA_CHECK_CTRLC
1445		Allow Control-C to interrupt FPGA configuration
1446
1447		CFG_FPGA_CHECK_ERROR
1448
1449		Check for configuration errors during FPGA bitfile
1450		loading. For example, abort during Virtex II
1451		configuration if the INIT_B line goes low (which
1452		indicated a CRC error).
1453
1454		CFG_FPGA_WAIT_INIT
1455
1456		Maximum time to wait for the INIT_B line to deassert
1457		after PROB_B has been deasserted during a Virtex II
1458		FPGA configuration sequence. The default time is 500
1459		mS.
1460
1461		CFG_FPGA_WAIT_BUSY
1462
1463		Maximum time to wait for BUSY to deassert during
1464		Virtex II FPGA configuration. The default is 5 mS.
1465
1466		CFG_FPGA_WAIT_CONFIG
1467
1468		Time to wait after FPGA configuration. The default is
1469		200 mS.
1470
1471- Configuration Management:
1472		CONFIG_IDENT_STRING
1473
1474		If defined, this string will be added to the U-Boot
1475		version information (U_BOOT_VERSION)
1476
1477- Vendor Parameter Protection:
1478
1479		U-Boot considers the values of the environment
1480		variables "serial#" (Board Serial Number) and
1481		"ethaddr" (Ethernet Address) to be parameters that
1482		are set once by the board vendor / manufacturer, and
1483		protects these variables from casual modification by
1484		the user. Once set, these variables are read-only,
1485		and write or delete attempts are rejected. You can
1486		change this behviour:
1487
1488		If CONFIG_ENV_OVERWRITE is #defined in your config
1489		file, the write protection for vendor parameters is
1490		completely disabled. Anybody can change or delete
1491		these parameters.
1492
1493		Alternatively, if you #define _both_ CONFIG_ETHADDR
1494		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1495		ethernet address is installed in the environment,
1496		which can be changed exactly ONCE by the user. [The
1497		serial# is unaffected by this, i. e. it remains
1498		read-only.]
1499
1500- Protected RAM:
1501		CONFIG_PRAM
1502
1503		Define this variable to enable the reservation of
1504		"protected RAM", i. e. RAM which is not overwritten
1505		by U-Boot. Define CONFIG_PRAM to hold the number of
1506		kB you want to reserve for pRAM. You can overwrite
1507		this default value by defining an environment
1508		variable "pram" to the number of kB you want to
1509		reserve. Note that the board info structure will
1510		still show the full amount of RAM. If pRAM is
1511		reserved, a new environment variable "mem" will
1512		automatically be defined to hold the amount of
1513		remaining RAM in a form that can be passed as boot
1514		argument to Linux, for instance like that:
1515
1516			setenv bootargs ... mem=\${mem}
1517			saveenv
1518
1519		This way you can tell Linux not to use this memory,
1520		either, which results in a memory region that will
1521		not be affected by reboots.
1522
1523		*WARNING* If your board configuration uses automatic
1524		detection of the RAM size, you must make sure that
1525		this memory test is non-destructive. So far, the
1526		following board configurations are known to be
1527		"pRAM-clean":
1528
1529			ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1530			HERMES, IP860, RPXlite, LWMON, LANTEC,
1531			PCU_E, FLAGADM, TQM8260
1532
1533- Error Recovery:
1534		CONFIG_PANIC_HANG
1535
1536		Define this variable to stop the system in case of a
1537		fatal error, so that you have to reset it manually.
1538		This is probably NOT a good idea for an embedded
1539		system where you want to system to reboot
1540		automatically as fast as possible, but it may be
1541		useful during development since you can try to debug
1542		the conditions that lead to the situation.
1543
1544		CONFIG_NET_RETRY_COUNT
1545
1546		This variable defines the number of retries for
1547		network operations like ARP, RARP, TFTP, or BOOTP
1548		before giving up the operation. If not defined, a
1549		default value of 5 is used.
1550
1551- Command Interpreter:
1552		CONFIG_AUTO_COMPLETE
1553
1554		Enable auto completion of commands using TAB.
1555
1556		Note that this feature has NOT been implemented yet
1557		for the "hush" shell.
1558
1559
1560		CFG_HUSH_PARSER
1561
1562		Define this variable to enable the "hush" shell (from
1563		Busybox) as command line interpreter, thus enabling
1564		powerful command line syntax like
1565		if...then...else...fi conditionals or `&&' and '||'
1566		constructs ("shell scripts").
1567
1568		If undefined, you get the old, much simpler behaviour
1569		with a somewhat smaller memory footprint.
1570
1571
1572		CFG_PROMPT_HUSH_PS2
1573
1574		This defines the secondary prompt string, which is
1575		printed when the command interpreter needs more input
1576		to complete a command. Usually "> ".
1577
1578	Note:
1579
1580		In the current implementation, the local variables
1581		space and global environment variables space are
1582		separated. Local variables are those you define by
1583		simply typing `name=value'. To access a local
1584		variable later on, you have write `$name' or
1585		`${name}'; to execute the contents of a variable
1586		directly type `$name' at the command prompt.
1587
1588		Global environment variables are those you use
1589		setenv/printenv to work with. To run a command stored
1590		in such a variable, you need to use the run command,
1591		and you must not use the '$' sign to access them.
1592
1593		To store commands and special characters in a
1594		variable, please use double quotation marks
1595		surrounding the whole text of the variable, instead
1596		of the backslashes before semicolons and special
1597		symbols.
1598
1599- Commandline Editing and History:
1600		CONFIG_CMDLINE_EDITING
1601
1602		Enable editiong and History functions for interactive
1603		commandline input operations
1604
1605- Default Environment:
1606		CONFIG_EXTRA_ENV_SETTINGS
1607
1608		Define this to contain any number of null terminated
1609		strings (variable = value pairs) that will be part of
1610		the default environment compiled into the boot image.
1611
1612		For example, place something like this in your
1613		board's config file:
1614
1615		#define CONFIG_EXTRA_ENV_SETTINGS \
1616			"myvar1=value1\0" \
1617			"myvar2=value2\0"
1618
1619		Warning: This method is based on knowledge about the
1620		internal format how the environment is stored by the
1621		U-Boot code. This is NOT an official, exported
1622		interface! Although it is unlikely that this format
1623		will change soon, there is no guarantee either.
1624		You better know what you are doing here.
1625
1626		Note: overly (ab)use of the default environment is
1627		discouraged. Make sure to check other ways to preset
1628		the environment like the autoscript function or the
1629		boot command first.
1630
1631- DataFlash Support:
1632		CONFIG_HAS_DATAFLASH
1633
1634		Defining this option enables DataFlash features and
1635		allows to read/write in Dataflash via the standard
1636		commands cp, md...
1637
1638- SystemACE Support:
1639		CONFIG_SYSTEMACE
1640
1641		Adding this option adds support for Xilinx SystemACE
1642		chips attached via some sort of local bus. The address
1643		of the chip must alsh be defined in the
1644		CFG_SYSTEMACE_BASE macro. For example:
1645
1646		#define CONFIG_SYSTEMACE
1647		#define CFG_SYSTEMACE_BASE 0xf0000000
1648
1649		When SystemACE support is added, the "ace" device type
1650		becomes available to the fat commands, i.e. fatls.
1651
1652- TFTP Fixed UDP Port:
1653		CONFIG_TFTP_PORT
1654
1655		If this is defined, the environment variable tftpsrcp
1656		is used to supply the TFTP UDP source port value.
1657		If tftpsrcp isn't defined, the normal pseudo-random port
1658		number generator is used.
1659
1660		Also, the environment variable tftpdstp is used to supply
1661		the TFTP UDP destination port value.  If tftpdstp isn't
1662		defined, the normal port 69 is used.
1663
1664		The purpose for tftpsrcp is to allow a TFTP server to
1665		blindly start the TFTP transfer using the pre-configured
1666		target IP address and UDP port. This has the effect of
1667		"punching through" the (Windows XP) firewall, allowing
1668		the remainder of the TFTP transfer to proceed normally.
1669		A better solution is to properly configure the firewall,
1670		but sometimes that is not allowed.
1671
1672- Show boot progress:
1673		CONFIG_SHOW_BOOT_PROGRESS
1674
1675		Defining this option allows to add some board-
1676		specific code (calling a user-provided function
1677		"show_boot_progress(int)") that enables you to show
1678		the system's boot progress on some display (for
1679		example, some LED's) on your board. At the moment,
1680		the following checkpoints are implemented:
1681
1682Legacy uImage format:
1683
1684  Arg	Where			When
1685    1	common/cmd_bootm.c	before attempting to boot an image
1686   -1	common/cmd_bootm.c	Image header has bad	 magic number
1687    2	common/cmd_bootm.c	Image header has correct magic number
1688   -2	common/cmd_bootm.c	Image header has bad	 checksum
1689    3	common/cmd_bootm.c	Image header has correct checksum
1690   -3	common/cmd_bootm.c	Image data   has bad	 checksum
1691    4	common/cmd_bootm.c	Image data   has correct checksum
1692   -4	common/cmd_bootm.c	Image is for unsupported architecture
1693    5	common/cmd_bootm.c	Architecture check OK
1694   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
1695    6	common/cmd_bootm.c	Image Type check OK
1696   -6	common/cmd_bootm.c	gunzip uncompression error
1697   -7	common/cmd_bootm.c	Unimplemented compression type
1698    7	common/cmd_bootm.c	Uncompression OK
1699    8	common/cmd_bootm.c	No uncompress/copy overwrite error
1700   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
1701
1702    9	common/image.c		Start initial ramdisk verification
1703  -10	common/image.c		Ramdisk header has bad	   magic number
1704  -11	common/image.c		Ramdisk header has bad	   checksum
1705   10	common/image.c		Ramdisk header is OK
1706  -12	common/image.c		Ramdisk data   has bad	   checksum
1707   11	common/image.c		Ramdisk data   has correct checksum
1708   12	common/image.c		Ramdisk verification complete, start loading
1709  -13	common/image.c		Wrong Image Type (not PPC Linux Ramdisk)
1710   13	common/image.c		Start multifile image verification
1711   14	common/image.c		No initial ramdisk, no multifile, continue.
1712
1713   15	lib_<arch>/bootm.c	All preparation done, transferring control to OS
1714
1715  -30	lib_ppc/board.c		Fatal error, hang the system
1716  -31	post/post.c		POST test failed, detected by post_output_backlog()
1717  -32	post/post.c		POST test failed, detected by post_run_single()
1718
1719   34	common/cmd_doc.c	before loading a Image from a DOC device
1720  -35	common/cmd_doc.c	Bad usage of "doc" command
1721   35	common/cmd_doc.c	correct usage of "doc" command
1722  -36	common/cmd_doc.c	No boot device
1723   36	common/cmd_doc.c	correct boot device
1724  -37	common/cmd_doc.c	Unknown Chip ID on boot device
1725   37	common/cmd_doc.c	correct chip ID found, device available
1726  -38	common/cmd_doc.c	Read Error on boot device
1727   38	common/cmd_doc.c	reading Image header from DOC device OK
1728  -39	common/cmd_doc.c	Image header has bad magic number
1729   39	common/cmd_doc.c	Image header has correct magic number
1730  -40	common/cmd_doc.c	Error reading Image from DOC device
1731   40	common/cmd_doc.c	Image header has correct magic number
1732   41	common/cmd_ide.c	before loading a Image from a IDE device
1733  -42	common/cmd_ide.c	Bad usage of "ide" command
1734   42	common/cmd_ide.c	correct usage of "ide" command
1735  -43	common/cmd_ide.c	No boot device
1736   43	common/cmd_ide.c	boot device found
1737  -44	common/cmd_ide.c	Device not available
1738   44	common/cmd_ide.c	Device available
1739  -45	common/cmd_ide.c	wrong partition selected
1740   45	common/cmd_ide.c	partition selected
1741  -46	common/cmd_ide.c	Unknown partition table
1742   46	common/cmd_ide.c	valid partition table found
1743  -47	common/cmd_ide.c	Invalid partition type
1744   47	common/cmd_ide.c	correct partition type
1745  -48	common/cmd_ide.c	Error reading Image Header on boot device
1746   48	common/cmd_ide.c	reading Image Header from IDE device OK
1747  -49	common/cmd_ide.c	Image header has bad magic number
1748   49	common/cmd_ide.c	Image header has correct magic number
1749  -50	common/cmd_ide.c	Image header has bad	 checksum
1750   50	common/cmd_ide.c	Image header has correct checksum
1751  -51	common/cmd_ide.c	Error reading Image from IDE device
1752   51	common/cmd_ide.c	reading Image from IDE device OK
1753   52	common/cmd_nand.c	before loading a Image from a NAND device
1754  -53	common/cmd_nand.c	Bad usage of "nand" command
1755   53	common/cmd_nand.c	correct usage of "nand" command
1756  -54	common/cmd_nand.c	No boot device
1757   54	common/cmd_nand.c	boot device found
1758  -55	common/cmd_nand.c	Unknown Chip ID on boot device
1759   55	common/cmd_nand.c	correct chip ID found, device available
1760  -56	common/cmd_nand.c	Error reading Image Header on boot device
1761   56	common/cmd_nand.c	reading Image Header from NAND device OK
1762  -57	common/cmd_nand.c	Image header has bad magic number
1763   57	common/cmd_nand.c	Image header has correct magic number
1764  -58	common/cmd_nand.c	Error reading Image from NAND device
1765   58	common/cmd_nand.c	reading Image from NAND device OK
1766
1767  -60	common/env_common.c	Environment has a bad CRC, using default
1768
1769   64	net/eth.c		starting with Ethernetconfiguration.
1770  -64	net/eth.c		no Ethernet found.
1771   65	net/eth.c		Ethernet found.
1772
1773  -80	common/cmd_net.c	usage wrong
1774   80	common/cmd_net.c	before calling NetLoop()
1775  -81	common/cmd_net.c	some error in NetLoop() occured
1776   81	common/cmd_net.c	NetLoop() back without error
1777  -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
1778   82	common/cmd_net.c	trying automatic boot
1779   83	common/cmd_net.c	running autoscript
1780  -83	common/cmd_net.c	some error in automatic boot or autoscript
1781   84	common/cmd_net.c	end without errors
1782
1783FIT uImage format:
1784
1785  Arg	Where			When
1786  100	common/cmd_bootm.c	Kernel FIT Image has correct format
1787 -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
1788  101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
1789 -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
1790  102	common/cmd_bootm.c	Kernel unit name specified
1791 -103	common/cmd_bootm.c	Can't get kernel subimage node offset
1792  103	common/cmd_bootm.c	Found configuration node
1793  104	common/cmd_bootm.c	Got kernel subimage node offset
1794 -104	common/cmd_bootm.c	Kernel subimage hash verification failed
1795  105	common/cmd_bootm.c	Kernel subimage hash verification OK
1796 -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
1797  106	common/cmd_bootm.c	Architecture check OK
1798 -106	common/cmd_bootm.c	Kernel subimage has wrong typea
1799  107	common/cmd_bootm.c	Kernel subimge type OK
1800 -107	common/cmd_bootm.c	Can't get kernel subimage data/size
1801  108	common/cmd_bootm.c	Got kernel subimage data/size
1802 -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
1803 -109	common/cmd_bootm.c	Can't get kernel subimage type
1804 -110	common/cmd_bootm.c	Can't get kernel subimage comp
1805 -111	common/cmd_bootm.c	Can't get kernel subimage os
1806 -112	common/cmd_bootm.c	Can't get kernel subimage load address
1807 -113	common/cmd_bootm.c	Image uncompress/copy overwrite error
1808
1809  120	common/image.c		Start initial ramdisk verification
1810 -120	common/image.c		Ramdisk FIT image has incorrect format
1811  121	common/image.c		Ramdisk FIT image has correct format
1812  122	common/image.c		No Ramdisk subimage unit name, using configuration
1813 -122	common/image.c		Can't get configuration for ramdisk subimage
1814  123	common/image.c		Ramdisk unit name specified
1815 -124	common/image.c		Can't get ramdisk subimage node offset
1816  125	common/image.c		Got ramdisk subimage node offset
1817 -125	common/image.c		Ramdisk subimage hash verification failed
1818  126	common/image.c		Ramdisk subimage hash verification OK
1819 -126	common/image.c		Ramdisk subimage for unsupported architecture
1820  127	common/image.c		Architecture check OK
1821 -127	common/image.c		Can't get ramdisk subimage data/size
1822  128	common/image.c		Got ramdisk subimage data/size
1823  129	common/image.c		Can't get ramdisk load address
1824 -129	common/image.c		Got ramdisk load address
1825
1826 -130	common/cmd_doc.c	Icorrect FIT image format
1827  131	common/cmd_doc.c	FIT image format OK
1828
1829 -140	common/cmd_ide.c	Icorrect FIT image format
1830  141	common/cmd_ide.c	FIT image format OK
1831
1832 -150	common/cmd_nand.c	Icorrect FIT image format
1833  151	common/cmd_nand.c	FIT image format OK
1834
1835
1836Modem Support:
1837--------------
1838
1839[so far only for SMDK2400 and TRAB boards]
1840
1841- Modem support endable:
1842		CONFIG_MODEM_SUPPORT
1843
1844- RTS/CTS Flow control enable:
1845		CONFIG_HWFLOW
1846
1847- Modem debug support:
1848		CONFIG_MODEM_SUPPORT_DEBUG
1849
1850		Enables debugging stuff (char screen[1024], dbg())
1851		for modem support. Useful only with BDI2000.
1852
1853- Interrupt support (PPC):
1854
1855		There are common interrupt_init() and timer_interrupt()
1856		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1857		for cpu specific initialization. interrupt_init_cpu()
1858		should set decrementer_count to appropriate value. If
1859		cpu resets decrementer automatically after interrupt
1860		(ppc4xx) it should set decrementer_count to zero.
1861		timer_interrupt() calls timer_interrupt_cpu() for cpu
1862		specific handling. If board has watchdog / status_led
1863		/ other_activity_monitor it works automatically from
1864		general timer_interrupt().
1865
1866- General:
1867
1868		In the target system modem support is enabled when a
1869		specific key (key combination) is pressed during
1870		power-on. Otherwise U-Boot will boot normally
1871		(autoboot). The key_pressed() fuction is called from
1872		board_init(). Currently key_pressed() is a dummy
1873		function, returning 1 and thus enabling modem
1874		initialization.
1875
1876		If there are no modem init strings in the
1877		environment, U-Boot proceed to autoboot; the
1878		previous output (banner, info printfs) will be
1879		supressed, though.
1880
1881		See also: doc/README.Modem
1882
1883
1884Configuration Settings:
1885-----------------------
1886
1887- CFG_LONGHELP: Defined when you want long help messages included;
1888		undefine this when you're short of memory.
1889
1890- CFG_PROMPT:	This is what U-Boot prints on the console to
1891		prompt for user input.
1892
1893- CFG_CBSIZE:	Buffer size for input from the Console
1894
1895- CFG_PBSIZE:	Buffer size for Console output
1896
1897- CFG_MAXARGS:	max. Number of arguments accepted for monitor commands
1898
1899- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1900		the application (usually a Linux kernel) when it is
1901		booted
1902
1903- CFG_BAUDRATE_TABLE:
1904		List of legal baudrate settings for this board.
1905
1906- CFG_CONSOLE_INFO_QUIET
1907		Suppress display of console information at boot.
1908
1909- CFG_CONSOLE_IS_IN_ENV
1910		If the board specific function
1911			extern int overwrite_console (void);
1912		returns 1, the stdin, stderr and stdout are switched to the
1913		serial port, else the settings in the environment are used.
1914
1915- CFG_CONSOLE_OVERWRITE_ROUTINE
1916		Enable the call to overwrite_console().
1917
1918- CFG_CONSOLE_ENV_OVERWRITE
1919		Enable overwrite of previous console environment settings.
1920
1921- CFG_MEMTEST_START, CFG_MEMTEST_END:
1922		Begin and End addresses of the area used by the
1923		simple memory test.
1924
1925- CFG_ALT_MEMTEST:
1926		Enable an alternate, more extensive memory test.
1927
1928- CFG_MEMTEST_SCRATCH:
1929		Scratch address used by the alternate memory test
1930		You only need to set this if address zero isn't writeable
1931
1932- CFG_MEM_TOP_HIDE (PPC only):
1933		If CFG_MEM_TOP_HIDE is defined in the board config header,
1934		this specified memory area will get subtracted from the top
1935		(end) of ram and won't get "touched" at all by U-Boot. By
1936		fixing up gd->ram_size the Linux kernel should gets passed
1937		the now "corrected" memory size and won't touch it either.
1938		This should work for arch/ppc and arch/powerpc. Only Linux
1939		board ports in arch/powerpc with bootwrapper support, that
1940		recalculate the memory size from the SDRAM controller setup
1941		will have to get fixed.
1942
1943		This option can be used as a workaround for the 440EPx/GRx
1944		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1945		be touched.
1946
1947		WARNING: Please make sure that this value is a multiple of
1948		the Linux page size (normally 4k). If this is not the case,
1949		then the end address of the Linux memory will be located at a
1950		non page size aligned address and this could cause major
1951		problems.
1952
1953- CFG_TFTP_LOADADDR:
1954		Default load address for network file downloads
1955
1956- CFG_LOADS_BAUD_CHANGE:
1957		Enable temporary baudrate change while serial download
1958
1959- CFG_SDRAM_BASE:
1960		Physical start address of SDRAM. _Must_ be 0 here.
1961
1962- CFG_MBIO_BASE:
1963		Physical start address of Motherboard I/O (if using a
1964		Cogent motherboard)
1965
1966- CFG_FLASH_BASE:
1967		Physical start address of Flash memory.
1968
1969- CFG_MONITOR_BASE:
1970		Physical start address of boot monitor code (set by
1971		make config files to be same as the text base address
1972		(TEXT_BASE) used when linking) - same as
1973		CFG_FLASH_BASE when booting from flash.
1974
1975- CFG_MONITOR_LEN:
1976		Size of memory reserved for monitor code, used to
1977		determine _at_compile_time_ (!) if the environment is
1978		embedded within the U-Boot image, or in a separate
1979		flash sector.
1980
1981- CFG_MALLOC_LEN:
1982		Size of DRAM reserved for malloc() use.
1983
1984- CFG_BOOTM_LEN:
1985		Normally compressed uImages are limited to an
1986		uncompressed size of 8 MBytes. If this is not enough,
1987		you can define CFG_BOOTM_LEN in your board config file
1988		to adjust this setting to your needs.
1989
1990- CFG_BOOTMAPSZ:
1991		Maximum size of memory mapped by the startup code of
1992		the Linux kernel; all data that must be processed by
1993		the Linux kernel (bd_info, boot arguments, eventually
1994		initrd image) must be put below this limit.
1995
1996- CFG_MAX_FLASH_BANKS:
1997		Max number of Flash memory banks
1998
1999- CFG_MAX_FLASH_SECT:
2000		Max number of sectors on a Flash chip
2001
2002- CFG_FLASH_ERASE_TOUT:
2003		Timeout for Flash erase operations (in ms)
2004
2005- CFG_FLASH_WRITE_TOUT:
2006		Timeout for Flash write operations (in ms)
2007
2008- CFG_FLASH_LOCK_TOUT
2009		Timeout for Flash set sector lock bit operation (in ms)
2010
2011- CFG_FLASH_UNLOCK_TOUT
2012		Timeout for Flash clear lock bits operation (in ms)
2013
2014- CFG_FLASH_PROTECTION
2015		If defined, hardware flash sectors protection is used
2016		instead of U-Boot software protection.
2017
2018- CFG_DIRECT_FLASH_TFTP:
2019
2020		Enable TFTP transfers directly to flash memory;
2021		without this option such a download has to be
2022		performed in two steps: (1) download to RAM, and (2)
2023		copy from RAM to flash.
2024
2025		The two-step approach is usually more reliable, since
2026		you can check if the download worked before you erase
2027		the flash, but in some situations (when sytem RAM is
2028		too limited to allow for a tempory copy of the
2029		downloaded image) this option may be very useful.
2030
2031- CFG_FLASH_CFI:
2032		Define if the flash driver uses extra elements in the
2033		common flash structure for storing flash geometry.
2034
2035- CFG_FLASH_CFI_DRIVER
2036		This option also enables the building of the cfi_flash driver
2037		in the drivers directory
2038
2039- CFG_FLASH_QUIET_TEST
2040		If this option is defined, the common CFI flash doesn't
2041		print it's warning upon not recognized FLASH banks. This
2042		is useful, if some of the configured banks are only
2043		optionally available.
2044
2045- CONFIG_FLASH_SHOW_PROGRESS
2046		If defined (must be an integer), print out countdown
2047		digits and dots.  Recommended value: 45 (9..1) for 80
2048		column displays, 15 (3..1) for 40 column displays.
2049
2050- CFG_RX_ETH_BUFFER:
2051		Defines the number of ethernet receive buffers. On some
2052		ethernet controllers it is recommended to set this value
2053		to 8 or even higher (EEPRO100 or 405 EMAC), since all
2054		buffers can be full shortly after enabling the interface
2055		on high ethernet traffic.
2056		Defaults to 4 if not defined.
2057
2058The following definitions that deal with the placement and management
2059of environment data (variable area); in general, we support the
2060following configurations:
2061
2062- CFG_ENV_IS_IN_FLASH:
2063
2064	Define this if the environment is in flash memory.
2065
2066	a) The environment occupies one whole flash sector, which is
2067	   "embedded" in the text segment with the U-Boot code. This
2068	   happens usually with "bottom boot sector" or "top boot
2069	   sector" type flash chips, which have several smaller
2070	   sectors at the start or the end. For instance, such a
2071	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2072	   such a case you would place the environment in one of the
2073	   4 kB sectors - with U-Boot code before and after it. With
2074	   "top boot sector" type flash chips, you would put the
2075	   environment in one of the last sectors, leaving a gap
2076	   between U-Boot and the environment.
2077
2078	- CFG_ENV_OFFSET:
2079
2080	   Offset of environment data (variable area) to the
2081	   beginning of flash memory; for instance, with bottom boot
2082	   type flash chips the second sector can be used: the offset
2083	   for this sector is given here.
2084
2085	   CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2086
2087	- CFG_ENV_ADDR:
2088
2089	   This is just another way to specify the start address of
2090	   the flash sector containing the environment (instead of
2091	   CFG_ENV_OFFSET).
2092
2093	- CFG_ENV_SECT_SIZE:
2094
2095	   Size of the sector containing the environment.
2096
2097
2098	b) Sometimes flash chips have few, equal sized, BIG sectors.
2099	   In such a case you don't want to spend a whole sector for
2100	   the environment.
2101
2102	- CFG_ENV_SIZE:
2103
2104	   If you use this in combination with CFG_ENV_IS_IN_FLASH
2105	   and CFG_ENV_SECT_SIZE, you can specify to use only a part
2106	   of this flash sector for the environment. This saves
2107	   memory for the RAM copy of the environment.
2108
2109	   It may also save flash memory if you decide to use this
2110	   when your environment is "embedded" within U-Boot code,
2111	   since then the remainder of the flash sector could be used
2112	   for U-Boot code. It should be pointed out that this is
2113	   STRONGLY DISCOURAGED from a robustness point of view:
2114	   updating the environment in flash makes it always
2115	   necessary to erase the WHOLE sector. If something goes
2116	   wrong before the contents has been restored from a copy in
2117	   RAM, your target system will be dead.
2118
2119	- CFG_ENV_ADDR_REDUND
2120	  CFG_ENV_SIZE_REDUND
2121
2122	   These settings describe a second storage area used to hold
2123	   a redundand copy of the environment data, so that there is
2124	   a valid backup copy in case there is a power failure during
2125	   a "saveenv" operation.
2126
2127BE CAREFUL! Any changes to the flash layout, and some changes to the
2128source code will make it necessary to adapt <board>/u-boot.lds*
2129accordingly!
2130
2131
2132- CFG_ENV_IS_IN_NVRAM:
2133
2134	Define this if you have some non-volatile memory device
2135	(NVRAM, battery buffered SRAM) which you want to use for the
2136	environment.
2137
2138	- CFG_ENV_ADDR:
2139	- CFG_ENV_SIZE:
2140
2141	  These two #defines are used to determin the memory area you
2142	  want to use for environment. It is assumed that this memory
2143	  can just be read and written to, without any special
2144	  provision.
2145
2146BE CAREFUL! The first access to the environment happens quite early
2147in U-Boot initalization (when we try to get the setting of for the
2148console baudrate). You *MUST* have mappend your NVRAM area then, or
2149U-Boot will hang.
2150
2151Please note that even with NVRAM we still use a copy of the
2152environment in RAM: we could work on NVRAM directly, but we want to
2153keep settings there always unmodified except somebody uses "saveenv"
2154to save the current settings.
2155
2156
2157- CFG_ENV_IS_IN_EEPROM:
2158
2159	Use this if you have an EEPROM or similar serial access
2160	device and a driver for it.
2161
2162	- CFG_ENV_OFFSET:
2163	- CFG_ENV_SIZE:
2164
2165	  These two #defines specify the offset and size of the
2166	  environment area within the total memory of your EEPROM.
2167
2168	- CFG_I2C_EEPROM_ADDR:
2169	  If defined, specified the chip address of the EEPROM device.
2170	  The default address is zero.
2171
2172	- CFG_EEPROM_PAGE_WRITE_BITS:
2173	  If defined, the number of bits used to address bytes in a
2174	  single page in the EEPROM device.  A 64 byte page, for example
2175	  would require six bits.
2176
2177	- CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2178	  If defined, the number of milliseconds to delay between
2179	  page writes.	The default is zero milliseconds.
2180
2181	- CFG_I2C_EEPROM_ADDR_LEN:
2182	  The length in bytes of the EEPROM memory array address.  Note
2183	  that this is NOT the chip address length!
2184
2185	- CFG_I2C_EEPROM_ADDR_OVERFLOW:
2186	  EEPROM chips that implement "address overflow" are ones
2187	  like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2188	  address and the extra bits end up in the "chip address" bit
2189	  slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2190	  byte chips.
2191
2192	  Note that we consider the length of the address field to
2193	  still be one byte because the extra address bits are hidden
2194	  in the chip address.
2195
2196	- CFG_EEPROM_SIZE:
2197	  The size in bytes of the EEPROM device.
2198
2199
2200- CFG_ENV_IS_IN_DATAFLASH:
2201
2202	Define this if you have a DataFlash memory device which you
2203	want to use for the environment.
2204
2205	- CFG_ENV_OFFSET:
2206	- CFG_ENV_ADDR:
2207	- CFG_ENV_SIZE:
2208
2209	  These three #defines specify the offset and size of the
2210	  environment area within the total memory of your DataFlash placed
2211	  at the specified address.
2212
2213- CFG_ENV_IS_IN_NAND:
2214
2215	Define this if you have a NAND device which you want to use
2216	for the environment.
2217
2218	- CFG_ENV_OFFSET:
2219	- CFG_ENV_SIZE:
2220
2221	  These two #defines specify the offset and size of the environment
2222	  area within the first NAND device.
2223
2224	- CFG_ENV_OFFSET_REDUND
2225
2226	  This setting describes a second storage area of CFG_ENV_SIZE
2227	  size used to hold a redundant copy of the environment data,
2228	  so that there is a valid backup copy in case there is a
2229	  power failure during a "saveenv" operation.
2230
2231	Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2232	to a block boundary, and CFG_ENV_SIZE must be a multiple of
2233	the NAND devices block size.
2234
2235- CFG_SPI_INIT_OFFSET
2236
2237	Defines offset to the initial SPI buffer area in DPRAM. The
2238	area is used at an early stage (ROM part) if the environment
2239	is configured to reside in the SPI EEPROM: We need a 520 byte
2240	scratch DPRAM area. It is used between the two initialization
2241	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2242	to be a good choice since it makes it far enough from the
2243	start of the data area as well as from the stack pointer.
2244
2245Please note that the environment is read-only until the monitor
2246has been relocated to RAM and a RAM copy of the environment has been
2247created; also, when using EEPROM you will have to use getenv_r()
2248until then to read environment variables.
2249
2250The environment is protected by a CRC32 checksum. Before the monitor
2251is relocated into RAM, as a result of a bad CRC you will be working
2252with the compiled-in default environment - *silently*!!! [This is
2253necessary, because the first environment variable we need is the
2254"baudrate" setting for the console - if we have a bad CRC, we don't
2255have any device yet where we could complain.]
2256
2257Note: once the monitor has been relocated, then it will complain if
2258the default environment is used; a new CRC is computed as soon as you
2259use the "saveenv" command to store a valid environment.
2260
2261- CFG_FAULT_ECHO_LINK_DOWN:
2262		Echo the inverted Ethernet link state to the fault LED.
2263
2264		Note: If this option is active, then CFG_FAULT_MII_ADDR
2265		      also needs to be defined.
2266
2267- CFG_FAULT_MII_ADDR:
2268		MII address of the PHY to check for the Ethernet link state.
2269
2270- CFG_64BIT_VSPRINTF:
2271		Makes vsprintf (and all *printf functions) support printing
2272		of 64bit values by using the L quantifier
2273
2274- CFG_64BIT_STRTOUL:
2275		Adds simple_strtoull that returns a 64bit value
2276
2277Low Level (hardware related) configuration options:
2278---------------------------------------------------
2279
2280- CFG_CACHELINE_SIZE:
2281		Cache Line Size of the CPU.
2282
2283- CFG_DEFAULT_IMMR:
2284		Default address of the IMMR after system reset.
2285
2286		Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2287		and RPXsuper) to be able to adjust the position of
2288		the IMMR register after a reset.
2289
2290- Floppy Disk Support:
2291		CFG_FDC_DRIVE_NUMBER
2292
2293		the default drive number (default value 0)
2294
2295		CFG_ISA_IO_STRIDE
2296
2297		defines the spacing between fdc chipset registers
2298		(default value 1)
2299
2300		CFG_ISA_IO_OFFSET
2301
2302		defines the offset of register from address. It
2303		depends on which part of the data bus is connected to
2304		the fdc chipset. (default value 0)
2305
2306		If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2307		CFG_FDC_DRIVE_NUMBER are undefined, they take their
2308		default value.
2309
2310		if CFG_FDC_HW_INIT is defined, then the function
2311		fdc_hw_init() is called at the beginning of the FDC
2312		setup. fdc_hw_init() must be provided by the board
2313		source code. It is used to make hardware dependant
2314		initializations.
2315
2316- CFG_IMMR:	Physical address of the Internal Memory.
2317		DO NOT CHANGE unless you know exactly what you're
2318		doing! (11-4) [MPC8xx/82xx systems only]
2319
2320- CFG_INIT_RAM_ADDR:
2321
2322		Start address of memory area that can be used for
2323		initial data and stack; please note that this must be
2324		writable memory that is working WITHOUT special
2325		initialization, i. e. you CANNOT use normal RAM which
2326		will become available only after programming the
2327		memory controller and running certain initialization
2328		sequences.
2329
2330		U-Boot uses the following memory types:
2331		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2332		- MPC824X: data cache
2333		- PPC4xx:  data cache
2334
2335- CFG_GBL_DATA_OFFSET:
2336
2337		Offset of the initial data structure in the memory
2338		area defined by CFG_INIT_RAM_ADDR. Usually
2339		CFG_GBL_DATA_OFFSET is chosen such that the initial
2340		data is located at the end of the available space
2341		(sometimes written as (CFG_INIT_RAM_END -
2342		CFG_INIT_DATA_SIZE), and the initial stack is just
2343		below that area (growing from (CFG_INIT_RAM_ADDR +
2344		CFG_GBL_DATA_OFFSET) downward.
2345
2346	Note:
2347		On the MPC824X (or other systems that use the data
2348		cache for initial memory) the address chosen for
2349		CFG_INIT_RAM_ADDR is basically arbitrary - it must
2350		point to an otherwise UNUSED address space between
2351		the top of RAM and the start of the PCI space.
2352
2353- CFG_SIUMCR:	SIU Module Configuration (11-6)
2354
2355- CFG_SYPCR:	System Protection Control (11-9)
2356
2357- CFG_TBSCR:	Time Base Status and Control (11-26)
2358
2359- CFG_PISCR:	Periodic Interrupt Status and Control (11-31)
2360
2361- CFG_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
2362
2363- CFG_SCCR:	System Clock and reset Control Register (15-27)
2364
2365- CFG_OR_TIMING_SDRAM:
2366		SDRAM timing
2367
2368- CFG_MAMR_PTA:
2369		periodic timer for refresh
2370
2371- CFG_DER:	Debug Event Register (37-47)
2372
2373- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2374  CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2375  CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2376  CFG_BR1_PRELIM:
2377		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2378
2379- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2380  CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2381  CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2382		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2383
2384- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2385  CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2386		Machine Mode Register and Memory Periodic Timer
2387		Prescaler definitions (SDRAM timing)
2388
2389- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2390		enable I2C microcode relocation patch (MPC8xx);
2391		define relocation offset in DPRAM [DSP2]
2392
2393- CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2394		enable SMC microcode relocation patch (MPC8xx);
2395		define relocation offset in DPRAM [SMC1]
2396
2397- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2398		enable SPI microcode relocation patch (MPC8xx);
2399		define relocation offset in DPRAM [SCC4]
2400
2401- CFG_USE_OSCCLK:
2402		Use OSCM clock mode on MBX8xx board. Be careful,
2403		wrong setting might damage your board. Read
2404		doc/README.MBX before setting this variable!
2405
2406- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2407		Offset of the bootmode word in DPRAM used by post
2408		(Power On Self Tests). This definition overrides
2409		#define'd default value in commproc.h resp.
2410		cpm_8260.h.
2411
2412- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2413  CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2414  CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2415  CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2416  CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2417  CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2418  CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2419  CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2420		Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2421
2422- CONFIG_SPD_EEPROM
2423		Get DDR timing information from an I2C EEPROM. Common
2424		with pluggable memory modules such as SODIMMs
2425
2426  SPD_EEPROM_ADDRESS
2427		I2C address of the SPD EEPROM
2428
2429- CFG_SPD_BUS_NUM
2430		If SPD EEPROM is on an I2C bus other than the first
2431		one, specify here. Note that the value must resolve
2432		to something your driver can deal with.
2433
2434- CFG_83XX_DDR_USES_CS0
2435		Only for 83xx systems. If specified, then DDR should
2436		be configured using CS0 and CS1 instead of CS2 and CS3.
2437
2438- CFG_83XX_DDR_USES_CS0
2439		Only for 83xx systems. If specified, then DDR should
2440		be configured using CS0 and CS1 instead of CS2 and CS3.
2441
2442- CONFIG_ETHER_ON_FEC[12]
2443		Define to enable FEC[12] on a 8xx series processor.
2444
2445- CONFIG_FEC[12]_PHY
2446		Define to the hardcoded PHY address which corresponds
2447		to the given FEC; i. e.
2448			#define CONFIG_FEC1_PHY 4
2449		means that the PHY with address 4 is connected to FEC1
2450
2451		When set to -1, means to probe for first available.
2452
2453- CONFIG_FEC[12]_PHY_NORXERR
2454		The PHY does not have a RXERR line (RMII only).
2455		(so program the FEC to ignore it).
2456
2457- CONFIG_RMII
2458		Enable RMII mode for all FECs.
2459		Note that this is a global option, we can't
2460		have one FEC in standard MII mode and another in RMII mode.
2461
2462- CONFIG_CRC32_VERIFY
2463		Add a verify option to the crc32 command.
2464		The syntax is:
2465
2466		=> crc32 -v <address> <count> <crc32>
2467
2468		Where address/count indicate a memory area
2469		and crc32 is the correct crc32 which the
2470		area should have.
2471
2472- CONFIG_LOOPW
2473		Add the "loopw" memory command. This only takes effect if
2474		the memory commands are activated globally (CONFIG_CMD_MEM).
2475
2476- CONFIG_MX_CYCLIC
2477		Add the "mdc" and "mwc" memory commands. These are cyclic
2478		"md/mw" commands.
2479		Examples:
2480
2481		=> mdc.b 10 4 500
2482		This command will print 4 bytes (10,11,12,13) each 500 ms.
2483
2484		=> mwc.l 100 12345678 10
2485		This command will write 12345678 to address 100 all 10 ms.
2486
2487		This only takes effect if the memory commands are activated
2488		globally (CONFIG_CMD_MEM).
2489
2490- CONFIG_SKIP_LOWLEVEL_INIT
2491- CONFIG_SKIP_RELOCATE_UBOOT
2492
2493		[ARM only] If these variables are defined, then
2494		certain low level initializations (like setting up
2495		the memory controller) are omitted and/or U-Boot does
2496		not relocate itself into RAM.
2497		Normally these variables MUST NOT be defined. The
2498		only exception is when U-Boot is loaded (to RAM) by
2499		some other boot loader or by a debugger which
2500		performs these intializations itself.
2501
2502
2503Building the Software:
2504======================
2505
2506Building U-Boot has been tested in several native build environments
2507and in many different cross environments. Of course we cannot support
2508all possibly existing versions of cross development tools in all
2509(potentially obsolete) versions. In case of tool chain problems we
2510recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2511which is extensively used to build and test U-Boot.
2512
2513If you are not using a native environment, it is assumed that you
2514have GNU cross compiling tools available in your path. In this case,
2515you must set the environment variable CROSS_COMPILE in your shell.
2516Note that no changes to the Makefile or any other source files are
2517necessary. For example using the ELDK on a 4xx CPU, please enter:
2518
2519	$ CROSS_COMPILE=ppc_4xx-
2520	$ export CROSS_COMPILE
2521
2522U-Boot is intended to be simple to build. After installing the
2523sources you must configure U-Boot for one specific board type. This
2524is done by typing:
2525
2526	make NAME_config
2527
2528where "NAME_config" is the name of one of the existing configu-
2529rations; see the main Makefile for supported names.
2530
2531Note: for some board special configuration names may exist; check if
2532      additional information is available from the board vendor; for
2533      instance, the TQM823L systems are available without (standard)
2534      or with LCD support. You can select such additional "features"
2535      when chosing the configuration, i. e.
2536
2537      make TQM823L_config
2538	- will configure for a plain TQM823L, i. e. no LCD support
2539
2540      make TQM823L_LCD_config
2541	- will configure for a TQM823L with U-Boot console on LCD
2542
2543      etc.
2544
2545
2546Finally, type "make all", and you should get some working U-Boot
2547images ready for download to / installation on your system:
2548
2549- "u-boot.bin" is a raw binary image
2550- "u-boot" is an image in ELF binary format
2551- "u-boot.srec" is in Motorola S-Record format
2552
2553By default the build is performed locally and the objects are saved
2554in the source directory. One of the two methods can be used to change
2555this behavior and build U-Boot to some external directory:
2556
25571. Add O= to the make command line invocations:
2558
2559	make O=/tmp/build distclean
2560	make O=/tmp/build NAME_config
2561	make O=/tmp/build all
2562
25632. Set environment variable BUILD_DIR to point to the desired location:
2564
2565	export BUILD_DIR=/tmp/build
2566	make distclean
2567	make NAME_config
2568	make all
2569
2570Note that the command line "O=" setting overrides the BUILD_DIR environment
2571variable.
2572
2573
2574Please be aware that the Makefiles assume you are using GNU make, so
2575for instance on NetBSD you might need to use "gmake" instead of
2576native "make".
2577
2578
2579If the system board that you have is not listed, then you will need
2580to port U-Boot to your hardware platform. To do this, follow these
2581steps:
2582
25831.  Add a new configuration option for your board to the toplevel
2584    "Makefile" and to the "MAKEALL" script, using the existing
2585    entries as examples. Note that here and at many other places
2586    boards and other names are listed in alphabetical sort order. Please
2587    keep this order.
25882.  Create a new directory to hold your board specific code. Add any
2589    files you need. In your board directory, you will need at least
2590    the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
25913.  Create a new configuration file "include/configs/<board>.h" for
2592    your board
25933.  If you're porting U-Boot to a new CPU, then also create a new
2594    directory to hold your CPU specific code. Add any files you need.
25954.  Run "make <board>_config" with your new name.
25965.  Type "make", and you should get a working "u-boot.srec" file
2597    to be installed on your target system.
25986.  Debug and solve any problems that might arise.
2599    [Of course, this last step is much harder than it sounds.]
2600
2601
2602Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2603==============================================================
2604
2605If you have modified U-Boot sources (for instance added a new board
2606or support for new devices, a new CPU, etc.) you are expected to
2607provide feedback to the other developers. The feedback normally takes
2608the form of a "patch", i. e. a context diff against a certain (latest
2609official or latest in the git repository) version of U-Boot sources.
2610
2611But before you submit such a patch, please verify that your modifi-
2612cation did not break existing code. At least make sure that *ALL* of
2613the supported boards compile WITHOUT ANY compiler warnings. To do so,
2614just run the "MAKEALL" script, which will configure and build U-Boot
2615for ALL supported system. Be warned, this will take a while. You can
2616select which (cross) compiler to use by passing a `CROSS_COMPILE'
2617environment variable to the script, i. e. to use the ELDK cross tools
2618you can type
2619
2620	CROSS_COMPILE=ppc_8xx- MAKEALL
2621
2622or to build on a native PowerPC system you can type
2623
2624	CROSS_COMPILE=' ' MAKEALL
2625
2626When using the MAKEALL script, the default behaviour is to build
2627U-Boot in the source directory. This location can be changed by
2628setting the BUILD_DIR environment variable. Also, for each target
2629built, the MAKEALL script saves two log files (<target>.ERR and
2630<target>.MAKEALL) in the <source dir>/LOG directory. This default
2631location can be changed by setting the MAKEALL_LOGDIR environment
2632variable. For example:
2633
2634	export BUILD_DIR=/tmp/build
2635	export MAKEALL_LOGDIR=/tmp/log
2636	CROSS_COMPILE=ppc_8xx- MAKEALL
2637
2638With the above settings build objects are saved in the /tmp/build,
2639log files are saved in the /tmp/log and the source tree remains clean
2640during the whole build process.
2641
2642
2643See also "U-Boot Porting Guide" below.
2644
2645
2646Monitor Commands - Overview:
2647============================
2648
2649go	- start application at address 'addr'
2650run	- run commands in an environment variable
2651bootm	- boot application image from memory
2652bootp	- boot image via network using BootP/TFTP protocol
2653tftpboot- boot image via network using TFTP protocol
2654	       and env variables "ipaddr" and "serverip"
2655	       (and eventually "gatewayip")
2656rarpboot- boot image via network using RARP/TFTP protocol
2657diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
2658loads	- load S-Record file over serial line
2659loadb	- load binary file over serial line (kermit mode)
2660md	- memory display
2661mm	- memory modify (auto-incrementing)
2662nm	- memory modify (constant address)
2663mw	- memory write (fill)
2664cp	- memory copy
2665cmp	- memory compare
2666crc32	- checksum calculation
2667imd	- i2c memory display
2668imm	- i2c memory modify (auto-incrementing)
2669inm	- i2c memory modify (constant address)
2670imw	- i2c memory write (fill)
2671icrc32	- i2c checksum calculation
2672iprobe	- probe to discover valid I2C chip addresses
2673iloop	- infinite loop on address range
2674isdram	- print SDRAM configuration information
2675sspi	- SPI utility commands
2676base	- print or set address offset
2677printenv- print environment variables
2678setenv	- set environment variables
2679saveenv - save environment variables to persistent storage
2680protect - enable or disable FLASH write protection
2681erase	- erase FLASH memory
2682flinfo	- print FLASH memory information
2683bdinfo	- print Board Info structure
2684iminfo	- print header information for application image
2685coninfo - print console devices and informations
2686ide	- IDE sub-system
2687loop	- infinite loop on address range
2688loopw	- infinite write loop on address range
2689mtest	- simple RAM test
2690icache	- enable or disable instruction cache
2691dcache	- enable or disable data cache
2692reset	- Perform RESET of the CPU
2693echo	- echo args to console
2694version - print monitor version
2695help	- print online help
2696?	- alias for 'help'
2697
2698
2699Monitor Commands - Detailed Description:
2700========================================
2701
2702TODO.
2703
2704For now: just type "help <command>".
2705
2706
2707Environment Variables:
2708======================
2709
2710U-Boot supports user configuration using Environment Variables which
2711can be made persistent by saving to Flash memory.
2712
2713Environment Variables are set using "setenv", printed using
2714"printenv", and saved to Flash using "saveenv". Using "setenv"
2715without a value can be used to delete a variable from the
2716environment. As long as you don't save the environment you are
2717working with an in-memory copy. In case the Flash area containing the
2718environment is erased by accident, a default environment is provided.
2719
2720Some configuration options can be set using Environment Variables:
2721
2722  baudrate	- see CONFIG_BAUDRATE
2723
2724  bootdelay	- see CONFIG_BOOTDELAY
2725
2726  bootcmd	- see CONFIG_BOOTCOMMAND
2727
2728  bootargs	- Boot arguments when booting an RTOS image
2729
2730  bootfile	- Name of the image to load with TFTP
2731
2732  autoload	- if set to "no" (any string beginning with 'n'),
2733		  "bootp" will just load perform a lookup of the
2734		  configuration from the BOOTP server, but not try to
2735		  load any image using TFTP
2736
2737  autoscript	- if set to "yes" commands like "loadb", "loady",
2738		  "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2739		  to automatically run script images (by internally
2740		  calling "autoscript").
2741
2742  autoscript_uname - if script image is in a format (FIT) this
2743		     variable is used to get script subimage unit name.
2744
2745  autostart	- if set to "yes", an image loaded using the "bootp",
2746		  "rarpboot", "tftpboot" or "diskboot" commands will
2747		  be automatically started (by internally calling
2748		  "bootm")
2749
2750		  If set to "no", a standalone image passed to the
2751		  "bootm" command will be copied to the load address
2752		  (and eventually uncompressed), but NOT be started.
2753		  This can be used to load and uncompress arbitrary
2754		  data.
2755
2756  i2cfast	- (PPC405GP|PPC405EP only)
2757		  if set to 'y' configures Linux I2C driver for fast
2758		  mode (400kHZ). This environment variable is used in
2759		  initialization code. So, for changes to be effective
2760		  it must be saved and board must be reset.
2761
2762  initrd_high	- restrict positioning of initrd images:
2763		  If this variable is not set, initrd images will be
2764		  copied to the highest possible address in RAM; this
2765		  is usually what you want since it allows for
2766		  maximum initrd size. If for some reason you want to
2767		  make sure that the initrd image is loaded below the
2768		  CFG_BOOTMAPSZ limit, you can set this environment
2769		  variable to a value of "no" or "off" or "0".
2770		  Alternatively, you can set it to a maximum upper
2771		  address to use (U-Boot will still check that it
2772		  does not overwrite the U-Boot stack and data).
2773
2774		  For instance, when you have a system with 16 MB
2775		  RAM, and want to reserve 4 MB from use by Linux,
2776		  you can do this by adding "mem=12M" to the value of
2777		  the "bootargs" variable. However, now you must make
2778		  sure that the initrd image is placed in the first
2779		  12 MB as well - this can be done with
2780
2781		  setenv initrd_high 00c00000
2782
2783		  If you set initrd_high to 0xFFFFFFFF, this is an
2784		  indication to U-Boot that all addresses are legal
2785		  for the Linux kernel, including addresses in flash
2786		  memory. In this case U-Boot will NOT COPY the
2787		  ramdisk at all. This may be useful to reduce the
2788		  boot time on your system, but requires that this
2789		  feature is supported by your Linux kernel.
2790
2791  ipaddr	- IP address; needed for tftpboot command
2792
2793  loadaddr	- Default load address for commands like "bootp",
2794		  "rarpboot", "tftpboot", "loadb" or "diskboot"
2795
2796  loads_echo	- see CONFIG_LOADS_ECHO
2797
2798  serverip	- TFTP server IP address; needed for tftpboot command
2799
2800  bootretry	- see CONFIG_BOOT_RETRY_TIME
2801
2802  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
2803
2804  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
2805
2806  ethprime	- When CONFIG_NET_MULTI is enabled controls which
2807		  interface is used first.
2808
2809  ethact	- When CONFIG_NET_MULTI is enabled controls which
2810		  interface is currently active. For example you
2811		  can do the following
2812
2813		  => setenv ethact FEC ETHERNET
2814		  => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2815		  => setenv ethact SCC ETHERNET
2816		  => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2817
2818  ethrotate	- When set to "no" U-Boot does not go through all
2819		  available network interfaces.
2820		  It just stays at the currently selected interface.
2821
2822   netretry	- When set to "no" each network operation will
2823		  either succeed or fail without retrying.
2824		  When set to "once" the network operation will
2825		  fail when all the available network interfaces
2826		  are tried once without success.
2827		  Useful on scripts which control the retry operation
2828		  themselves.
2829
2830  npe_ucode	- see CONFIG_IXP4XX_NPE_EXT_UCOD
2831		  if set load address for the npe microcode
2832
2833  tftpsrcport	- If this is set, the value is used for TFTP's
2834		  UDP source port.
2835
2836  tftpdstport	- If this is set, the value is used for TFTP's UDP
2837		  destination port instead of the Well Know Port 69.
2838
2839   vlan		- When set to a value < 4095 the traffic over
2840		  ethernet is encapsulated/received over 802.1q
2841		  VLAN tagged frames.
2842
2843The following environment variables may be used and automatically
2844updated by the network boot commands ("bootp" and "rarpboot"),
2845depending the information provided by your boot server:
2846
2847  bootfile	- see above
2848  dnsip		- IP address of your Domain Name Server
2849  dnsip2	- IP address of your secondary Domain Name Server
2850  gatewayip	- IP address of the Gateway (Router) to use
2851  hostname	- Target hostname
2852  ipaddr	- see above
2853  netmask	- Subnet Mask
2854  rootpath	- Pathname of the root filesystem on the NFS server
2855  serverip	- see above
2856
2857
2858There are two special Environment Variables:
2859
2860  serial#	- contains hardware identification information such
2861		  as type string and/or serial number
2862  ethaddr	- Ethernet address
2863
2864These variables can be set only once (usually during manufacturing of
2865the board). U-Boot refuses to delete or overwrite these variables
2866once they have been set once.
2867
2868
2869Further special Environment Variables:
2870
2871  ver		- Contains the U-Boot version string as printed
2872		  with the "version" command. This variable is
2873		  readonly (see CONFIG_VERSION_VARIABLE).
2874
2875
2876Please note that changes to some configuration parameters may take
2877only effect after the next boot (yes, that's just like Windoze :-).
2878
2879
2880Command Line Parsing:
2881=====================
2882
2883There are two different command line parsers available with U-Boot:
2884the old "simple" one, and the much more powerful "hush" shell:
2885
2886Old, simple command line parser:
2887--------------------------------
2888
2889- supports environment variables (through setenv / saveenv commands)
2890- several commands on one line, separated by ';'
2891- variable substitution using "... ${name} ..." syntax
2892- special characters ('$', ';') can be escaped by prefixing with '\',
2893  for example:
2894	setenv bootcmd bootm \${address}
2895- You can also escape text by enclosing in single apostrophes, for example:
2896	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2897
2898Hush shell:
2899-----------
2900
2901- similar to Bourne shell, with control structures like
2902  if...then...else...fi, for...do...done; while...do...done,
2903  until...do...done, ...
2904- supports environment ("global") variables (through setenv / saveenv
2905  commands) and local shell variables (through standard shell syntax
2906  "name=value"); only environment variables can be used with "run"
2907  command
2908
2909General rules:
2910--------------
2911
2912(1) If a command line (or an environment variable executed by a "run"
2913    command) contains several commands separated by semicolon, and
2914    one of these commands fails, then the remaining commands will be
2915    executed anyway.
2916
2917(2) If you execute several variables with one call to run (i. e.
2918    calling run with a list af variables as arguments), any failing
2919    command will cause "run" to terminate, i. e. the remaining
2920    variables are not executed.
2921
2922Note for Redundant Ethernet Interfaces:
2923=======================================
2924
2925Some boards come with redundant ethernet interfaces; U-Boot supports
2926such configurations and is capable of automatic selection of a
2927"working" interface when needed. MAC assignment works as follows:
2928
2929Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2930MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2931"eth1addr" (=>eth1), "eth2addr", ...
2932
2933If the network interface stores some valid MAC address (for instance
2934in SROM), this is used as default address if there is NO correspon-
2935ding setting in the environment; if the corresponding environment
2936variable is set, this overrides the settings in the card; that means:
2937
2938o If the SROM has a valid MAC address, and there is no address in the
2939  environment, the SROM's address is used.
2940
2941o If there is no valid address in the SROM, and a definition in the
2942  environment exists, then the value from the environment variable is
2943  used.
2944
2945o If both the SROM and the environment contain a MAC address, and
2946  both addresses are the same, this MAC address is used.
2947
2948o If both the SROM and the environment contain a MAC address, and the
2949  addresses differ, the value from the environment is used and a
2950  warning is printed.
2951
2952o If neither SROM nor the environment contain a MAC address, an error
2953  is raised.
2954
2955
2956Image Formats:
2957==============
2958
2959U-Boot is capable of booting (and performing other auxiliary operations on)
2960images in two formats:
2961
2962New uImage format (FIT)
2963-----------------------
2964
2965Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2966to Flattened Device Tree). It allows the use of images with multiple
2967components (several kernels, ramdisks, etc.), with contents protected by
2968SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2969
2970
2971Old uImage format
2972-----------------
2973
2974Old image format is based on binary files which can be basically anything,
2975preceded by a special header; see the definitions in include/image.h for
2976details; basically, the header defines the following image properties:
2977
2978* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2979  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2980  LynxOS, pSOS, QNX, RTEMS, ARTOS;
2981  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2982* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2983  IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2984  Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2985* Compression Type (uncompressed, gzip, bzip2)
2986* Load Address
2987* Entry Point
2988* Image Name
2989* Image Timestamp
2990
2991The header is marked by a special Magic Number, and both the header
2992and the data portions of the image are secured against corruption by
2993CRC32 checksums.
2994
2995
2996Linux Support:
2997==============
2998
2999Although U-Boot should support any OS or standalone application
3000easily, the main focus has always been on Linux during the design of
3001U-Boot.
3002
3003U-Boot includes many features that so far have been part of some
3004special "boot loader" code within the Linux kernel. Also, any
3005"initrd" images to be used are no longer part of one big Linux image;
3006instead, kernel and "initrd" are separate images. This implementation
3007serves several purposes:
3008
3009- the same features can be used for other OS or standalone
3010  applications (for instance: using compressed images to reduce the
3011  Flash memory footprint)
3012
3013- it becomes much easier to port new Linux kernel versions because
3014  lots of low-level, hardware dependent stuff are done by U-Boot
3015
3016- the same Linux kernel image can now be used with different "initrd"
3017  images; of course this also means that different kernel images can
3018  be run with the same "initrd". This makes testing easier (you don't
3019  have to build a new "zImage.initrd" Linux image when you just
3020  change a file in your "initrd"). Also, a field-upgrade of the
3021  software is easier now.
3022
3023
3024Linux HOWTO:
3025============
3026
3027Porting Linux to U-Boot based systems:
3028---------------------------------------
3029
3030U-Boot cannot save you from doing all the necessary modifications to
3031configure the Linux device drivers for use with your target hardware
3032(no, we don't intend to provide a full virtual machine interface to
3033Linux :-).
3034
3035But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3036
3037Just make sure your machine specific header file (for instance
3038include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3039Information structure as we define in include/u-boot.h, and make
3040sure that your definition of IMAP_ADDR uses the same value as your
3041U-Boot configuration in CFG_IMMR.
3042
3043
3044Configuring the Linux kernel:
3045-----------------------------
3046
3047No specific requirements for U-Boot. Make sure you have some root
3048device (initial ramdisk, NFS) for your target system.
3049
3050
3051Building a Linux Image:
3052-----------------------
3053
3054With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3055not used. If you use recent kernel source, a new build target
3056"uImage" will exist which automatically builds an image usable by
3057U-Boot. Most older kernels also have support for a "pImage" target,
3058which was introduced for our predecessor project PPCBoot and uses a
3059100% compatible format.
3060
3061Example:
3062
3063	make TQM850L_config
3064	make oldconfig
3065	make dep
3066	make uImage
3067
3068The "uImage" build target uses a special tool (in 'tools/mkimage') to
3069encapsulate a compressed Linux kernel image with header	 information,
3070CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3071
3072* build a standard "vmlinux" kernel image (in ELF binary format):
3073
3074* convert the kernel into a raw binary image:
3075
3076	${CROSS_COMPILE}-objcopy -O binary \
3077				 -R .note -R .comment \
3078				 -S vmlinux linux.bin
3079
3080* compress the binary image:
3081
3082	gzip -9 linux.bin
3083
3084* package compressed binary image for U-Boot:
3085
3086	mkimage -A ppc -O linux -T kernel -C gzip \
3087		-a 0 -e 0 -n "Linux Kernel Image" \
3088		-d linux.bin.gz uImage
3089
3090
3091The "mkimage" tool can also be used to create ramdisk images for use
3092with U-Boot, either separated from the Linux kernel image, or
3093combined into one file. "mkimage" encapsulates the images with a 64
3094byte header containing information about target architecture,
3095operating system, image type, compression method, entry points, time
3096stamp, CRC32 checksums, etc.
3097
3098"mkimage" can be called in two ways: to verify existing images and
3099print the header information, or to build new images.
3100
3101In the first form (with "-l" option) mkimage lists the information
3102contained in the header of an existing U-Boot image; this includes
3103checksum verification:
3104
3105	tools/mkimage -l image
3106	  -l ==> list image header information
3107
3108The second form (with "-d" option) is used to build a U-Boot image
3109from a "data file" which is used as image payload:
3110
3111	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3112		      -n name -d data_file image
3113	  -A ==> set architecture to 'arch'
3114	  -O ==> set operating system to 'os'
3115	  -T ==> set image type to 'type'
3116	  -C ==> set compression type 'comp'
3117	  -a ==> set load address to 'addr' (hex)
3118	  -e ==> set entry point to 'ep' (hex)
3119	  -n ==> set image name to 'name'
3120	  -d ==> use image data from 'datafile'
3121
3122Right now, all Linux kernels for PowerPC systems use the same load
3123address (0x00000000), but the entry point address depends on the
3124kernel version:
3125
3126- 2.2.x kernels have the entry point at 0x0000000C,
3127- 2.3.x and later kernels have the entry point at 0x00000000.
3128
3129So a typical call to build a U-Boot image would read:
3130
3131	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3132	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3133	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3134	> examples/uImage.TQM850L
3135	Image Name:   2.4.4 kernel for TQM850L
3136	Created:      Wed Jul 19 02:34:59 2000
3137	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
3138	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
3139	Load Address: 0x00000000
3140	Entry Point:  0x00000000
3141
3142To verify the contents of the image (or check for corruption):
3143
3144	-> tools/mkimage -l examples/uImage.TQM850L
3145	Image Name:   2.4.4 kernel for TQM850L
3146	Created:      Wed Jul 19 02:34:59 2000
3147	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
3148	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
3149	Load Address: 0x00000000
3150	Entry Point:  0x00000000
3151
3152NOTE: for embedded systems where boot time is critical you can trade
3153speed for memory and install an UNCOMPRESSED image instead: this
3154needs more space in Flash, but boots much faster since it does not
3155need to be uncompressed:
3156
3157	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3158	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3159	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3160	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3161	> examples/uImage.TQM850L-uncompressed
3162	Image Name:   2.4.4 kernel for TQM850L
3163	Created:      Wed Jul 19 02:34:59 2000
3164	Image Type:   PowerPC Linux Kernel Image (uncompressed)
3165	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
3166	Load Address: 0x00000000
3167	Entry Point:  0x00000000
3168
3169
3170Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3171when your kernel is intended to use an initial ramdisk:
3172
3173	-> tools/mkimage -n 'Simple Ramdisk Image' \
3174	> -A ppc -O linux -T ramdisk -C gzip \
3175	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3176	Image Name:   Simple Ramdisk Image
3177	Created:      Wed Jan 12 14:01:50 2000
3178	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
3179	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
3180	Load Address: 0x00000000
3181	Entry Point:  0x00000000
3182
3183
3184Installing a Linux Image:
3185-------------------------
3186
3187To downloading a U-Boot image over the serial (console) interface,
3188you must convert the image to S-Record format:
3189
3190	objcopy -I binary -O srec examples/image examples/image.srec
3191
3192The 'objcopy' does not understand the information in the U-Boot
3193image header, so the resulting S-Record file will be relative to
3194address 0x00000000. To load it to a given address, you need to
3195specify the target address as 'offset' parameter with the 'loads'
3196command.
3197
3198Example: install the image to address 0x40100000 (which on the
3199TQM8xxL is in the first Flash bank):
3200
3201	=> erase 40100000 401FFFFF
3202
3203	.......... done
3204	Erased 8 sectors
3205
3206	=> loads 40100000
3207	## Ready for S-Record download ...
3208	~>examples/image.srec
3209	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3210	...
3211	15989 15990 15991 15992
3212	[file transfer complete]
3213	[connected]
3214	## Start Addr = 0x00000000
3215
3216
3217You can check the success of the download using the 'iminfo' command;
3218this includes a checksum verification so you can be sure no data
3219corruption happened:
3220
3221	=> imi 40100000
3222
3223	## Checking Image at 40100000 ...
3224	   Image Name:	 2.2.13 for initrd on TQM850L
3225	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
3226	   Data Size:	 335725 Bytes = 327 kB = 0 MB
3227	   Load Address: 00000000
3228	   Entry Point:	 0000000c
3229	   Verifying Checksum ... OK
3230
3231
3232Boot Linux:
3233-----------
3234
3235The "bootm" command is used to boot an application that is stored in
3236memory (RAM or Flash). In case of a Linux kernel image, the contents
3237of the "bootargs" environment variable is passed to the kernel as
3238parameters. You can check and modify this variable using the
3239"printenv" and "setenv" commands:
3240
3241
3242	=> printenv bootargs
3243	bootargs=root=/dev/ram
3244
3245	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3246
3247	=> printenv bootargs
3248	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3249
3250	=> bootm 40020000
3251	## Booting Linux kernel at 40020000 ...
3252	   Image Name:	 2.2.13 for NFS on TQM850L
3253	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
3254	   Data Size:	 381681 Bytes = 372 kB = 0 MB
3255	   Load Address: 00000000
3256	   Entry Point:	 0000000c
3257	   Verifying Checksum ... OK
3258	   Uncompressing Kernel Image ... OK
3259	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
3260	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3261	time_init: decrementer frequency = 187500000/60
3262	Calibrating delay loop... 49.77 BogoMIPS
3263	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3264	...
3265
3266If you want to boot a Linux kernel with initial ram disk, you pass
3267the memory addresses of both the kernel and the initrd image (PPBCOOT
3268format!) to the "bootm" command:
3269
3270	=> imi 40100000 40200000
3271
3272	## Checking Image at 40100000 ...
3273	   Image Name:	 2.2.13 for initrd on TQM850L
3274	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
3275	   Data Size:	 335725 Bytes = 327 kB = 0 MB
3276	   Load Address: 00000000
3277	   Entry Point:	 0000000c
3278	   Verifying Checksum ... OK
3279
3280	## Checking Image at 40200000 ...
3281	   Image Name:	 Simple Ramdisk Image
3282	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
3283	   Data Size:	 566530 Bytes = 553 kB = 0 MB
3284	   Load Address: 00000000
3285	   Entry Point:	 00000000
3286	   Verifying Checksum ... OK
3287
3288	=> bootm 40100000 40200000
3289	## Booting Linux kernel at 40100000 ...
3290	   Image Name:	 2.2.13 for initrd on TQM850L
3291	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
3292	   Data Size:	 335725 Bytes = 327 kB = 0 MB
3293	   Load Address: 00000000
3294	   Entry Point:	 0000000c
3295	   Verifying Checksum ... OK
3296	   Uncompressing Kernel Image ... OK
3297	## Loading RAMDisk Image at 40200000 ...
3298	   Image Name:	 Simple Ramdisk Image
3299	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
3300	   Data Size:	 566530 Bytes = 553 kB = 0 MB
3301	   Load Address: 00000000
3302	   Entry Point:	 00000000
3303	   Verifying Checksum ... OK
3304	   Loading Ramdisk ... OK
3305	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
3306	Boot arguments: root=/dev/ram
3307	time_init: decrementer frequency = 187500000/60
3308	Calibrating delay loop... 49.77 BogoMIPS
3309	...
3310	RAMDISK: Compressed image found at block 0
3311	VFS: Mounted root (ext2 filesystem).
3312
3313	bash#
3314
3315Boot Linux and pass a flat device tree:
3316-----------
3317
3318First, U-Boot must be compiled with the appropriate defines. See the section
3319titled "Linux Kernel Interface" above for a more in depth explanation. The
3320following is an example of how to start a kernel and pass an updated
3321flat device tree:
3322
3323=> print oftaddr
3324oftaddr=0x300000
3325=> print oft
3326oft=oftrees/mpc8540ads.dtb
3327=> tftp $oftaddr $oft
3328Speed: 1000, full duplex
3329Using TSEC0 device
3330TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3331Filename 'oftrees/mpc8540ads.dtb'.
3332Load address: 0x300000
3333Loading: #
3334done
3335Bytes transferred = 4106 (100a hex)
3336=> tftp $loadaddr $bootfile
3337Speed: 1000, full duplex
3338Using TSEC0 device
3339TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3340Filename 'uImage'.
3341Load address: 0x200000
3342Loading:############
3343done
3344Bytes transferred = 1029407 (fb51f hex)
3345=> print loadaddr
3346loadaddr=200000
3347=> print oftaddr
3348oftaddr=0x300000
3349=> bootm $loadaddr - $oftaddr
3350## Booting image at 00200000 ...
3351   Image Name:	 Linux-2.6.17-dirty
3352   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
3353   Data Size:	 1029343 Bytes = 1005.2 kB
3354   Load Address: 00000000
3355   Entry Point:	 00000000
3356   Verifying Checksum ... OK
3357   Uncompressing Kernel Image ... OK
3358Booting using flat device tree at 0x300000
3359Using MPC85xx ADS machine description
3360Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3361[snip]
3362
3363
3364More About U-Boot Image Types:
3365------------------------------
3366
3367U-Boot supports the following image types:
3368
3369   "Standalone Programs" are directly runnable in the environment
3370	provided by U-Boot; it is expected that (if they behave
3371	well) you can continue to work in U-Boot after return from
3372	the Standalone Program.
3373   "OS Kernel Images" are usually images of some Embedded OS which
3374	will take over control completely. Usually these programs
3375	will install their own set of exception handlers, device
3376	drivers, set up the MMU, etc. - this means, that you cannot
3377	expect to re-enter U-Boot except by resetting the CPU.
3378   "RAMDisk Images" are more or less just data blocks, and their
3379	parameters (address, size) are passed to an OS kernel that is
3380	being started.
3381   "Multi-File Images" contain several images, typically an OS
3382	(Linux) kernel image and one or more data images like
3383	RAMDisks. This construct is useful for instance when you want
3384	to boot over the network using BOOTP etc., where the boot
3385	server provides just a single image file, but you want to get
3386	for instance an OS kernel and a RAMDisk image.
3387
3388	"Multi-File Images" start with a list of image sizes, each
3389	image size (in bytes) specified by an "uint32_t" in network
3390	byte order. This list is terminated by an "(uint32_t)0".
3391	Immediately after the terminating 0 follow the images, one by
3392	one, all aligned on "uint32_t" boundaries (size rounded up to
3393	a multiple of 4 bytes).
3394
3395   "Firmware Images" are binary images containing firmware (like
3396	U-Boot or FPGA images) which usually will be programmed to
3397	flash memory.
3398
3399   "Script files" are command sequences that will be executed by
3400	U-Boot's command interpreter; this feature is especially
3401	useful when you configure U-Boot to use a real shell (hush)
3402	as command interpreter.
3403
3404
3405Standalone HOWTO:
3406=================
3407
3408One of the features of U-Boot is that you can dynamically load and
3409run "standalone" applications, which can use some resources of
3410U-Boot like console I/O functions or interrupt services.
3411
3412Two simple examples are included with the sources:
3413
3414"Hello World" Demo:
3415-------------------
3416
3417'examples/hello_world.c' contains a small "Hello World" Demo
3418application; it is automatically compiled when you build U-Boot.
3419It's configured to run at address 0x00040004, so you can play with it
3420like that:
3421
3422	=> loads
3423	## Ready for S-Record download ...
3424	~>examples/hello_world.srec
3425	1 2 3 4 5 6 7 8 9 10 11 ...
3426	[file transfer complete]
3427	[connected]
3428	## Start Addr = 0x00040004
3429
3430	=> go 40004 Hello World! This is a test.
3431	## Starting application at 0x00040004 ...
3432	Hello World
3433	argc = 7
3434	argv[0] = "40004"
3435	argv[1] = "Hello"
3436	argv[2] = "World!"
3437	argv[3] = "This"
3438	argv[4] = "is"
3439	argv[5] = "a"
3440	argv[6] = "test."
3441	argv[7] = "<NULL>"
3442	Hit any key to exit ...
3443
3444	## Application terminated, rc = 0x0
3445
3446Another example, which demonstrates how to register a CPM interrupt
3447handler with the U-Boot code, can be found in 'examples/timer.c'.
3448Here, a CPM timer is set up to generate an interrupt every second.
3449The interrupt service routine is trivial, just printing a '.'
3450character, but this is just a demo program. The application can be
3451controlled by the following keys:
3452
3453	? - print current values og the CPM Timer registers
3454	b - enable interrupts and start timer
3455	e - stop timer and disable interrupts
3456	q - quit application
3457
3458	=> loads
3459	## Ready for S-Record download ...
3460	~>examples/timer.srec
3461	1 2 3 4 5 6 7 8 9 10 11 ...
3462	[file transfer complete]
3463	[connected]
3464	## Start Addr = 0x00040004
3465
3466	=> go 40004
3467	## Starting application at 0x00040004 ...
3468	TIMERS=0xfff00980
3469	Using timer 1
3470	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3471
3472Hit 'b':
3473	[q, b, e, ?] Set interval 1000000 us
3474	Enabling timer
3475Hit '?':
3476	[q, b, e, ?] ........
3477	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3478Hit '?':
3479	[q, b, e, ?] .
3480	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3481Hit '?':
3482	[q, b, e, ?] .
3483	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3484Hit '?':
3485	[q, b, e, ?] .
3486	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3487Hit 'e':
3488	[q, b, e, ?] ...Stopping timer
3489Hit 'q':
3490	[q, b, e, ?] ## Application terminated, rc = 0x0
3491
3492
3493Minicom warning:
3494================
3495
3496Over time, many people have reported problems when trying to use the
3497"minicom" terminal emulation program for serial download. I (wd)
3498consider minicom to be broken, and recommend not to use it. Under
3499Unix, I recommend to use C-Kermit for general purpose use (and
3500especially for kermit binary protocol download ("loadb" command), and
3501use "cu" for S-Record download ("loads" command).
3502
3503Nevertheless, if you absolutely want to use it try adding this
3504configuration to your "File transfer protocols" section:
3505
3506	   Name	   Program			Name U/D FullScr IO-Red. Multi
3507	X  kermit  /usr/bin/kermit -i -l %l -s	 Y    U	   Y	   N	  N
3508	Y  kermit  /usr/bin/kermit -i -l %l -r	 N    D	   Y	   N	  N
3509
3510
3511NetBSD Notes:
3512=============
3513
3514Starting at version 0.9.2, U-Boot supports NetBSD both as host
3515(build U-Boot) and target system (boots NetBSD/mpc8xx).
3516
3517Building requires a cross environment; it is known to work on
3518NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3519need gmake since the Makefiles are not compatible with BSD make).
3520Note that the cross-powerpc package does not install include files;
3521attempting to build U-Boot will fail because <machine/ansi.h> is
3522missing.  This file has to be installed and patched manually:
3523
3524	# cd /usr/pkg/cross/powerpc-netbsd/include
3525	# mkdir powerpc
3526	# ln -s powerpc machine
3527	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3528	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
3529
3530Native builds *don't* work due to incompatibilities between native
3531and U-Boot include files.
3532
3533Booting assumes that (the first part of) the image booted is a
3534stage-2 loader which in turn loads and then invokes the kernel
3535proper. Loader sources will eventually appear in the NetBSD source
3536tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3537meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3538
3539
3540Implementation Internals:
3541=========================
3542
3543The following is not intended to be a complete description of every
3544implementation detail. However, it should help to understand the
3545inner workings of U-Boot and make it easier to port it to custom
3546hardware.
3547
3548
3549Initial Stack, Global Data:
3550---------------------------
3551
3552The implementation of U-Boot is complicated by the fact that U-Boot
3553starts running out of ROM (flash memory), usually without access to
3554system RAM (because the memory controller is not initialized yet).
3555This means that we don't have writable Data or BSS segments, and BSS
3556is not initialized as zero. To be able to get a C environment working
3557at all, we have to allocate at least a minimal stack. Implementation
3558options for this are defined and restricted by the CPU used: Some CPU
3559models provide on-chip memory (like the IMMR area on MPC8xx and
3560MPC826x processors), on others (parts of) the data cache can be
3561locked as (mis-) used as memory, etc.
3562
3563	Chris Hallinan posted a good summary of these issues to the
3564	u-boot-users mailing list:
3565
3566	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3567	From: "Chris Hallinan" <clh@net1plus.com>
3568	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3569	...
3570
3571	Correct me if I'm wrong, folks, but the way I understand it
3572	is this: Using DCACHE as initial RAM for Stack, etc, does not
3573	require any physical RAM backing up the cache. The cleverness
3574	is that the cache is being used as a temporary supply of
3575	necessary storage before the SDRAM controller is setup. It's
3576	beyond the scope of this list to expain the details, but you
3577	can see how this works by studying the cache architecture and
3578	operation in the architecture and processor-specific manuals.
3579
3580	OCM is On Chip Memory, which I believe the 405GP has 4K. It
3581	is another option for the system designer to use as an
3582	initial stack/ram area prior to SDRAM being available. Either
3583	option should work for you. Using CS 4 should be fine if your
3584	board designers haven't used it for something that would
3585	cause you grief during the initial boot! It is frequently not
3586	used.
3587
3588	CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3589	with your processor/board/system design. The default value
3590	you will find in any recent u-boot distribution in
3591	walnut.h should work for you. I'd set it to a value larger
3592	than your SDRAM module. If you have a 64MB SDRAM module, set
3593	it above 400_0000. Just make sure your board has no resources
3594	that are supposed to respond to that address! That code in
3595	start.S has been around a while and should work as is when
3596	you get the config right.
3597
3598	-Chris Hallinan
3599	DS4.COM, Inc.
3600
3601It is essential to remember this, since it has some impact on the C
3602code for the initialization procedures:
3603
3604* Initialized global data (data segment) is read-only. Do not attempt
3605  to write it.
3606
3607* Do not use any unitialized global data (or implicitely initialized
3608  as zero data - BSS segment) at all - this is undefined, initiali-
3609  zation is performed later (when relocating to RAM).
3610
3611* Stack space is very limited. Avoid big data buffers or things like
3612  that.
3613
3614Having only the stack as writable memory limits means we cannot use
3615normal global data to share information beween the code. But it
3616turned out that the implementation of U-Boot can be greatly
3617simplified by making a global data structure (gd_t) available to all
3618functions. We could pass a pointer to this data as argument to _all_
3619functions, but this would bloat the code. Instead we use a feature of
3620the GCC compiler (Global Register Variables) to share the data: we
3621place a pointer (gd) to the global data into a register which we
3622reserve for this purpose.
3623
3624When choosing a register for such a purpose we are restricted by the
3625relevant  (E)ABI  specifications for the current architecture, and by
3626GCC's implementation.
3627
3628For PowerPC, the following registers have specific use:
3629	R1:	stack pointer
3630	R2:	reserved for system use
3631	R3-R4:	parameter passing and return values
3632	R5-R10: parameter passing
3633	R13:	small data area pointer
3634	R30:	GOT pointer
3635	R31:	frame pointer
3636
3637	(U-Boot also uses R14 as internal GOT pointer.)
3638
3639    ==> U-Boot will use R2 to hold a pointer to the global data
3640
3641    Note: on PPC, we could use a static initializer (since the
3642    address of the global data structure is known at compile time),
3643    but it turned out that reserving a register results in somewhat
3644    smaller code - although the code savings are not that big (on
3645    average for all boards 752 bytes for the whole U-Boot image,
3646    624 text + 127 data).
3647
3648On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3649	http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3650
3651    ==> U-Boot will use P5 to hold a pointer to the global data
3652
3653On ARM, the following registers are used:
3654
3655	R0:	function argument word/integer result
3656	R1-R3:	function argument word
3657	R9:	GOT pointer
3658	R10:	stack limit (used only if stack checking if enabled)
3659	R11:	argument (frame) pointer
3660	R12:	temporary workspace
3661	R13:	stack pointer
3662	R14:	link register
3663	R15:	program counter
3664
3665    ==> U-Boot will use R8 to hold a pointer to the global data
3666
3667NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3668or current versions of GCC may "optimize" the code too much.
3669
3670Memory Management:
3671------------------
3672
3673U-Boot runs in system state and uses physical addresses, i.e. the
3674MMU is not used either for address mapping nor for memory protection.
3675
3676The available memory is mapped to fixed addresses using the memory
3677controller. In this process, a contiguous block is formed for each
3678memory type (Flash, SDRAM, SRAM), even when it consists of several
3679physical memory banks.
3680
3681U-Boot is installed in the first 128 kB of the first Flash bank (on
3682TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3683booting and sizing and initializing DRAM, the code relocates itself
3684to the upper end of DRAM. Immediately below the U-Boot code some
3685memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3686configuration setting]. Below that, a structure with global Board
3687Info data is placed, followed by the stack (growing downward).
3688
3689Additionally, some exception handler code is copied to the low 8 kB
3690of DRAM (0x00000000 ... 0x00001FFF).
3691
3692So a typical memory configuration with 16 MB of DRAM could look like
3693this:
3694
3695	0x0000 0000	Exception Vector code
3696	      :
3697	0x0000 1FFF
3698	0x0000 2000	Free for Application Use
3699	      :
3700	      :
3701
3702	      :
3703	      :
3704	0x00FB FF20	Monitor Stack (Growing downward)
3705	0x00FB FFAC	Board Info Data and permanent copy of global data
3706	0x00FC 0000	Malloc Arena
3707	      :
3708	0x00FD FFFF
3709	0x00FE 0000	RAM Copy of Monitor Code
3710	...		eventually: LCD or video framebuffer
3711	...		eventually: pRAM (Protected RAM - unchanged by reset)
3712	0x00FF FFFF	[End of RAM]
3713
3714
3715System Initialization:
3716----------------------
3717
3718In the reset configuration, U-Boot starts at the reset entry point
3719(on most PowerPC systens at address 0x00000100). Because of the reset
3720configuration for CS0# this is a mirror of the onboard Flash memory.
3721To be able to re-map memory U-Boot then jumps to its link address.
3722To be able to implement the initialization code in C, a (small!)
3723initial stack is set up in the internal Dual Ported RAM (in case CPUs
3724which provide such a feature like MPC8xx or MPC8260), or in a locked
3725part of the data cache. After that, U-Boot initializes the CPU core,
3726the caches and the SIU.
3727
3728Next, all (potentially) available memory banks are mapped using a
3729preliminary mapping. For example, we put them on 512 MB boundaries
3730(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3731on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3732programmed for SDRAM access. Using the temporary configuration, a
3733simple memory test is run that determines the size of the SDRAM
3734banks.
3735
3736When there is more than one SDRAM bank, and the banks are of
3737different size, the largest is mapped first. For equal size, the first
3738bank (CS2#) is mapped first. The first mapping is always for address
37390x00000000, with any additional banks following immediately to create
3740contiguous memory starting from 0.
3741
3742Then, the monitor installs itself at the upper end of the SDRAM area
3743and allocates memory for use by malloc() and for the global Board
3744Info data; also, the exception vector code is copied to the low RAM
3745pages, and the final stack is set up.
3746
3747Only after this relocation will you have a "normal" C environment;
3748until that you are restricted in several ways, mostly because you are
3749running from ROM, and because the code will have to be relocated to a
3750new address in RAM.
3751
3752
3753U-Boot Porting Guide:
3754----------------------
3755
3756[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3757list, October 2002]
3758
3759
3760int main (int argc, char *argv[])
3761{
3762	sighandler_t no_more_time;
3763
3764	signal (SIGALRM, no_more_time);
3765	alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3766
3767	if (available_money > available_manpower) {
3768		pay consultant to port U-Boot;
3769		return 0;
3770	}
3771
3772	Download latest U-Boot source;
3773
3774	Subscribe to u-boot-users mailing list;
3775
3776	if (clueless) {
3777		email ("Hi, I am new to U-Boot, how do I get started?");
3778	}
3779
3780	while (learning) {
3781		Read the README file in the top level directory;
3782		Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3783		Read the source, Luke;
3784	}
3785
3786	if (available_money > toLocalCurrency ($2500)) {
3787		Buy a BDI2000;
3788	} else {
3789		Add a lot of aggravation and time;
3790	}
3791
3792	Create your own board support subdirectory;
3793
3794	Create your own board config file;
3795
3796	while (!running) {
3797		do {
3798			Add / modify source code;
3799		} until (compiles);
3800		Debug;
3801		if (clueless)
3802			email ("Hi, I am having problems...");
3803	}
3804	Send patch file to Wolfgang;
3805
3806	return 0;
3807}
3808
3809void no_more_time (int sig)
3810{
3811      hire_a_guru();
3812}
3813
3814
3815Coding Standards:
3816-----------------
3817
3818All contributions to U-Boot should conform to the Linux kernel
3819coding style; see the file "Documentation/CodingStyle" and the script
3820"scripts/Lindent" in your Linux kernel source directory.  In sources
3821originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3822spaces before parameters to function calls) is actually used.
3823
3824Source files originating from a different project (for example the
3825MTD subsystem) are generally exempt from these guidelines and are not
3826reformated to ease subsequent migration to newer versions of those
3827sources.
3828
3829Please note that U-Boot is implemented in C (and to some small parts in
3830Assembler); no C++ is used, so please do not use C++ style comments (//)
3831in your code.
3832
3833Please also stick to the following formatting rules:
3834- remove any trailing white space
3835- use TAB characters for indentation, not spaces
3836- make sure NOT to use DOS '\r\n' line feeds
3837- do not add more than 2 empty lines to source files
3838- do not add trailing empty lines to source files
3839
3840Submissions which do not conform to the standards may be returned
3841with a request to reformat the changes.
3842
3843
3844Submitting Patches:
3845-------------------
3846
3847Since the number of patches for U-Boot is growing, we need to
3848establish some rules. Submissions which do not conform to these rules
3849may be rejected, even when they contain important and valuable stuff.
3850
3851Patches shall be sent to the u-boot-users mailing list.
3852
3853Please see http://www.denx.de/wiki/UBoot/Patches for details.
3854
3855When you send a patch, please include the following information with
3856it:
3857
3858* For bug fixes: a description of the bug and how your patch fixes
3859  this bug. Please try to include a way of demonstrating that the
3860  patch actually fixes something.
3861
3862* For new features: a description of the feature and your
3863  implementation.
3864
3865* A CHANGELOG entry as plaintext (separate from the patch)
3866
3867* For major contributions, your entry to the CREDITS file
3868
3869* When you add support for a new board, don't forget to add this
3870  board to the MAKEALL script, too.
3871
3872* If your patch adds new configuration options, don't forget to
3873  document these in the README file.
3874
3875* The patch itself. If you are using git (which is *strongly*
3876  recommended) you can easily generate the patch using the
3877  "git-format-patch". If you then use "git-send-email" to send it to
3878  the U-Boot mailing list, you will avoid most of the common problems
3879  with some other mail clients.
3880
3881  If you cannot use git, use "diff -purN OLD NEW". If your version of
3882  diff does not support these options, then get the latest version of
3883  GNU diff.
3884
3885  The current directory when running this command shall be the parent
3886  directory of the U-Boot source tree (i. e. please make sure that
3887  your patch includes sufficient directory information for the
3888  affected files).
3889
3890  We prefer patches as plain text. MIME attachments are discouraged,
3891  and compressed attachments must not be used.
3892
3893* If one logical set of modifications affects or creates several
3894  files, all these changes shall be submitted in a SINGLE patch file.
3895
3896* Changesets that contain different, unrelated modifications shall be
3897  submitted as SEPARATE patches, one patch per changeset.
3898
3899
3900Notes:
3901
3902* Before sending the patch, run the MAKEALL script on your patched
3903  source tree and make sure that no errors or warnings are reported
3904  for any of the boards.
3905
3906* Keep your modifications to the necessary minimum: A patch
3907  containing several unrelated changes or arbitrary reformats will be
3908  returned with a request to re-formatting / split it.
3909
3910* If you modify existing code, make sure that your new code does not
3911  add to the memory footprint of the code ;-) Small is beautiful!
3912  When adding new features, these should compile conditionally only
3913  (using #ifdef), and the resulting code with the new feature
3914  disabled must not need more memory than the old code without your
3915  modification.
3916
3917* Remember that there is a size limit of 40 kB per message on the
3918  u-boot-users mailing list. Bigger patches will be moderated. If
3919  they are reasonable and not bigger than 100 kB, they will be
3920  acknowledged. Even bigger patches should be avoided.
3921