xref: /rk3399_rockchip-uboot/README (revision 8564acf936726c5568d71e4fa93a0ae9814e0d07)
1#
2# (C) Copyright 2000 - 2002
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 and ARM processors, which can be
29installed in a boot ROM and used to initialize and test the hardware
30or to download and run application code.
31
32The development of U-Boot is closely related to Linux: some parts of
33the source code originate in the Linux source tree, we have some
34header files in common, and special provision has been made to
35support booting of Linux images.
36
37Some attention has been paid to make this software easily
38configurable and extendable. For instance, all monitor commands are
39implemented with the same call interface, so that it's very easy to
40add new commands. Also, instead of permanently adding rarely used
41code (for instance hardware test utilities) to the monitor, you can
42load and run it dynamically.
43
44
45Status:
46=======
47
48In general, all boards for which a configuration option exists in the
49Makefile have been tested to some extent and can be considered
50"working". In fact, many of them are used in production systems.
51
52In case of problems see the CHANGELOG and CREDITS files to find out
53who contributed the specific port.
54
55
56Where to get help:
57==================
58
59In case you have questions about, problems with or contributions for
60U-Boot you should send a message to the U-Boot mailing list at
61<u-boot-users@lists.sourceforge.net>. There is also an archive of
62previous traffic on the mailing list - please search the archive
63before asking FAQ's. Please see
64http://lists.sourceforge.net/lists/listinfo/u-boot-users/
65
66
67Where we come from:
68===================
69
70- start from 8xxrom sources
71- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
72- clean up code
73- make it easier to add custom boards
74- make it possible to add other [PowerPC] CPUs
75- extend functions, especially:
76  * Provide extended interface to Linux boot loader
77  * S-Record download
78  * network boot
79  * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80- create ARMBoot project (http://sourceforge.net/projects/armboot)
81- add other CPU families (starting with ARM)
82- create U-Boot project (http://sourceforge.net/projects/u-boot)
83
84
85Names and Spelling:
86===================
87
88The "official" name of this project is "Das U-Boot". The spelling
89"U-Boot" shall be used in all written text (documentation, comments
90in source files etc.). Example:
91
92	This is the README file for the U-Boot project.
93
94File names etc. shall be based on the string "u-boot". Examples:
95
96	include/asm-ppc/u-boot.h
97
98	#include <asm/u-boot.h>
99
100Variable names, preprocessor constants etc. shall be either based on
101the string "u_boot" or on "U_BOOT". Example:
102
103	U_BOOT_VERSION		u_boot_logo
104	IH_OS_U_BOOT		u_boot_hush_start
105
106
107Versioning:
108===========
109
110U-Boot uses a 3 level version number containing a version, a
111sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112sub-version "34", and patchlevel "4".
113
114The patchlevel is used to indicate certain stages of development
115between released versions, i. e. officially released versions of
116U-Boot will always have a patchlevel of "0".
117
118
119Directory Hierarchy:
120====================
121
122- board		Board dependend files
123- common	Misc architecture independend functions
124- cpu		CPU specific files
125- disk		Code for disk drive partition handling
126- doc		Documentation (don't expect too much)
127- drivers	Common used device drivers
128- dtt		Digital Thermometer and Thermostat drivers
129- examples	Example code for standalone applications, etc.
130- include	Header Files
131- disk		Harddisk interface code
132- net		Networking code
133- ppc		Files generic to PowerPC architecture
134- post		Power On Self Test
135- post/arch		Symlink to architecture specific Power On Self Test
136- post/arch-ppc		PowerPC architecture specific Power On Self Test
137- post/cpu/mpc8260	MPC8260 CPU specific Power On Self Test
138- post/cpu/mpc8xx	MPC8xx CPU specific Power On Self Test
139- rtc		Real Time Clock drivers
140- tools		Tools to build S-Record or U-Boot images, etc.
141
142- cpu/74xx_7xx	Files specific to Motorola MPC74xx and 7xx CPUs
143- cpu/mpc5xx	Files specific to Motorola MPC5xx  CPUs
144- cpu/mpc8xx	Files specific to Motorola MPC8xx  CPUs
145- cpu/mpc824x	Files specific to Motorola MPC824x CPUs
146- cpu/mpc8260	Files specific to Motorola MPC8260 CPU
147- cpu/ppc4xx	Files specific to IBM	   4xx	   CPUs
148
149- board/LEOX/   Files specific to boards manufactured by The LEOX team
150- board/LEOX/elpt860	Files specific to ELPT860 boards
151- board/RPXClassic
152		Files specific to RPXClassic boards
153- board/RPXlite	Files specific to RPXlite    boards
154- board/at91rm9200dk Files specific to AT91RM9200DK boards
155- board/c2mon	Files specific to c2mon	     boards
156- board/cmi	Files specific to cmi        boards
157- board/cogent	Files specific to Cogent     boards
158		(need further configuration)
159		Files specific to CPCIISER4  boards
160- board/cpu86	Files specific to CPU86      boards
161- board/cray/	Files specific to boards manufactured by Cray
162- board/cray/L1		Files specific to L1         boards
163- board/cu824	Files specific to CU824	     boards
164- board/ebony   Files specific to IBM Ebony board
165- board/eric	Files specific to ERIC	     boards
166- board/esd/	Files specific to boards manufactured by ESD
167- board/esd/adciop	Files specific to ADCIOP     boards
168- board/esd/ar405	Files specific to AR405	     boards
169- board/esd/canbt	Files specific to CANBT	     boards
170- board/esd/cpci405	Files specific to CPCI405    boards
171- board/esd/cpciiser4	Files specific to CPCIISER4  boards
172- board/esd/common	Common files for ESD boards
173- board/esd/dasa_sim	Files specific to DASA_SIM   boards
174- board/esd/du405	Files specific to DU405      boards
175- board/esd/ocrtc	Files specific to OCRTC      boards
176- board/esd/pci405	Files specific to PCI405     boards
177- board/esteem192e
178		Files specific to ESTEEM192E boards
179- board/etx094	Files specific to ETX_094    boards
180- board/evb64260
181		Files specific to EVB64260   boards
182- board/fads	Files specific to FADS	     boards
183- board/flagadm Files specific to FLAGADM    boards
184- board/gen860t Files specific to GEN860T and GEN860T_SC    boards
185- board/genietv Files specific to GENIETV    boards
186- board/gth	Files specific to GTH	     boards
187- board/hermes	Files specific to HERMES     boards
188- board/hymod	Files specific to HYMOD	     boards
189- board/icu862	Files specific to ICU862     boards
190- board/ip860	Files specific to IP860	     boards
191- board/iphase4539
192		Files specific to Interphase4539 boards
193- board/ivm	Files specific to IVMS8/IVML24 boards
194- board/lantec	Files specific to LANTEC     boards
195- board/lwmon	Files specific to LWMON	     boards
196- board/mbx8xx	Files specific to MBX	     boards
197- board/mpc8260ads
198		Files specific to MMPC8260ADS boards
199- board/mpl/	Files specific to boards manufactured by MPL
200- board/mpl/common	Common files for MPL boards
201- board/mpl/pip405	Files specific to PIP405     boards
202- board/mpl/mip405	Files specific to MIP405     boards
203- board/musenki	Files specific to MUSEKNI    boards
204- board/mvs1	Files specific to MVS1       boards
205- board/nx823   Files specific to NX823      boards
206- board/oxc	Files specific to OXC        boards
207- board/pcippc2	Files specific to PCIPPC2/PCIPPC6 boards
208- board/pm826	Files specific to PM826      boards
209- board/ppmc8260
210		Files specific to PPMC8260   boards
211- board/rpxsuper
212		Files specific to RPXsuper   boards
213- board/rsdproto
214		Files specific to RSDproto   boards
215- board/sandpoint
216		Files specific to Sandpoint  boards
217- board/sbc8260	Files specific to SBC8260    boards
218- board/sacsng	Files specific to SACSng     boards
219- board/siemens Files specific to boards manufactured by Siemens AG
220- board/siemens/CCM	Files specific to CCM	     boards
221- board/siemens/IAD210	Files specific to IAD210     boards
222- board/siemens/SCM	Files specific to SCM        boards
223- board/siemens/pcu_e	Files specific to PCU_E	     boards
224- board/sixnet	Files specific to SIXNET     boards
225- board/spd8xx	Files specific to SPD8xxTS   boards
226- board/tqm8260 Files specific to TQM8260    boards
227- board/tqm8xx	Files specific to TQM8xxL    boards
228- board/w7o	Files specific to W7O        boards
229- board/walnut405
230		Files specific to Walnut405  boards
231- board/westel/	Files specific to boards manufactured by Westel Wireless
232- board/westel/amx860	Files specific to AMX860     boards
233- board/utx8245	Files specific to UTX8245   boards
234
235Software Configuration:
236=======================
237
238Configuration is usually done using C preprocessor defines; the
239rationale behind that is to avoid dead code whenever possible.
240
241There are two classes of configuration variables:
242
243* Configuration _OPTIONS_:
244  These are selectable by the user and have names beginning with
245  "CONFIG_".
246
247* Configuration _SETTINGS_:
248  These depend on the hardware etc. and should not be meddled with if
249  you don't know what you're doing; they have names beginning with
250  "CFG_".
251
252Later we will add a configuration tool - probably similar to or even
253identical to what's used for the Linux kernel. Right now, we have to
254do the configuration by hand, which means creating some symbolic
255links and editing some configuration files. We use the TQM8xxL boards
256as an example here.
257
258
259Selection of Processor Architecture and Board Type:
260---------------------------------------------------
261
262For all supported boards there are ready-to-use default
263configurations available; just type "make <board_name>_config".
264
265Example: For a TQM823L module type:
266
267	cd u-boot
268	make TQM823L_config
269
270For the Cogent platform, you need to specify the cpu type as well;
271e.g. "make cogent_mpc8xx_config". And also configure the cogent
272directory according to the instructions in cogent/README.
273
274
275Configuration Options:
276----------------------
277
278Configuration depends on the combination of board and CPU type; all
279such information is kept in a configuration file
280"include/configs/<board_name>.h".
281
282Example: For a TQM823L module, all configuration settings are in
283"include/configs/TQM823L.h".
284
285
286Many of the options are named exactly as the corresponding Linux
287kernel configuration options. The intention is to make it easier to
288build a config tool - later.
289
290
291The following options need to be configured:
292
293- CPU Type:	Define exactly one of
294
295		PowerPC based CPUs:
296		-------------------
297		CONFIG_MPC823,	CONFIG_MPC850,	CONFIG_MPC855,	CONFIG_MPC860
298	or	CONFIG_MPC5xx
299	or	CONFIG_MPC824X, CONFIG_MPC8260
300	or	CONFIG_IOP480
301	or	CONFIG_405GP
302	or	CONFIG_440
303	or	CONFIG_MPC74xx
304	or	CONFIG_750FX
305
306		ARM based CPUs:
307		---------------
308		CONFIG_SA1110
309		CONFIG_ARM7
310		CONFIG_PXA250
311
312
313- Board Type:	Define exactly one of
314
315		PowerPC based boards:
316		---------------------
317
318		CONFIG_ADCIOP,     CONFIG_ICU862      CONFIG_RPXsuper,
319		CONFIG_ADS860,     CONFIG_IP860,      CONFIG_SM850,
320		CONFIG_AMX860,     CONFIG_IPHASE4539, CONFIG_SPD823TS,
321		CONFIG_AR405,      CONFIG_IVML24,     CONFIG_SXNI855T,
322		CONFIG_BAB7xx,     CONFIG_IVML24_128, CONFIG_Sandpoint8240,
323		CONFIG_CANBT,      CONFIG_IVML24_256, CONFIG_Sandpoint8245,
324		CONFIG_CCM,        CONFIG_IVMS8,      CONFIG_TQM823L,
325		CONFIG_CPCI405,    CONFIG_IVMS8_128,  CONFIG_TQM850L,
326		CONFIG_CPCI4052,   CONFIG_IVMS8_256,  CONFIG_TQM855L,
327		CONFIG_CPCIISER4,  CONFIG_LANTEC,     CONFIG_TQM860L,
328		CONFIG_CPU86,      CONFIG_MBX,        CONFIG_TQM8260,
329		CONFIG_CRAYL1,     CONFIG_MBX860T,    CONFIG_TTTech,
330		CONFIG_CU824,      CONFIG_MHPC,       CONFIG_UTX8245,
331		CONFIG_DASA_SIM,   CONFIG_MIP405,     CONFIG_W7OLMC,
332		CONFIG_DU405,      CONFIG_MOUSSE,     CONFIG_W7OLMG,
333		CONFIG_ELPPC,      CONFIG_MPC8260ADS, CONFIG_WALNUT405,
334		CONFIG_ERIC,       CONFIG_MUSENKI,    CONFIG_ZUMA,
335		CONFIG_ESTEEM192E, CONFIG_MVS1,       CONFIG_c2mon,
336		CONFIG_ETX094,     CONFIG_NX823,      CONFIG_cogent_mpc8260,
337		CONFIG_EVB64260,   CONFIG_OCRTC,      CONFIG_cogent_mpc8xx,
338		CONFIG_FADS823,    CONFIG_ORSG,       CONFIG_ep8260,
339		CONFIG_FADS850SAR, CONFIG_OXC,        CONFIG_gw8260,
340		CONFIG_FADS860T,   CONFIG_PCI405,     CONFIG_hermes,
341		CONFIG_FLAGADM,    CONFIG_PCIPPC2,    CONFIG_hymod,
342		CONFIG_FPS850L,    CONFIG_PCIPPC6,    CONFIG_lwmon,
343		CONFIG_GEN860T,    CONFIG_PIP405,     CONFIG_pcu_e,
344		CONFIG_GENIETV,    CONFIG_PM826,      CONFIG_ppmc8260,
345		CONFIG_GTH,        CONFIG_RPXClassic, CONFIG_rsdproto,
346		CONFIG_IAD210,     CONFIG_RPXlite,    CONFIG_sbc8260,
347		CONFIG_EBONY,      CONFIG_sacsng,     CONFIG_FPS860L,
348		CONFIG_V37,        CONFIG_ELPT860,    CONFIG_CMI,
349		CONFIG_NETVIA,     CONFIG_RBC823
350
351		ARM based boards:
352		-----------------
353
354		CONFIG_HHP_CRADLE,  CONFIG_DNP1110,    CONFIG_EP7312,
355		CONFIG_IMPA7,       CONFIG_LART,       CONFIG_LUBBOCK,
356		CONFIG_SHANNON,     CONFIG_SMDK2400,   CONFIG_SMDK2410,
357		CONFIG_TRAB,	    CONFIG_AT91RM9200DK
358
359
360- CPU Module Type: (if CONFIG_COGENT is defined)
361		Define exactly one of
362		CONFIG_CMA286_60_OLD
363--- FIXME --- not tested yet:
364		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
365		CONFIG_CMA287_23, CONFIG_CMA287_50
366
367- Motherboard Type: (if CONFIG_COGENT is defined)
368		Define exactly one of
369		CONFIG_CMA101, CONFIG_CMA102
370
371- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
372		Define one or more of
373		CONFIG_CMA302
374
375- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
376		Define one or more of
377		CONFIG_LCD_HEARTBEAT	- update a character position on
378					  the lcd display every second with
379					  a "rotator" |\-/|\-/
380
381- MPC824X Family Member (if CONFIG_MPC824X is defined)
382	Define exactly one of
383	CONFIG_MPC8240, CONFIG_MPC8245
384
385- 8xx CPU Options: (if using an 8xx cpu)
386		Define one or more of
387		CONFIG_8xx_GCLK_FREQ	- if get_gclk_freq() can not work e.g.
388					  no 32KHz reference PIT/RTC clock
389
390- Clock Interface:
391		CONFIG_CLOCKS_IN_MHZ
392
393		U-Boot stores all clock information in Hz
394		internally. For binary compatibility with older Linux
395		kernels (which expect the clocks passed in the
396		bd_info data to be in MHz) the environment variable
397		"clocks_in_mhz" can be defined so that U-Boot
398		converts clock data to MHZ before passing it to the
399		Linux kernel.
400
401		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
402		"clocks_in_mhz=1" is  automatically  included  in  the
403		default environment.
404
405- Console Interface:
406		Depending on board, define exactly one serial port
407		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
408		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
409		console by defining CONFIG_8xx_CONS_NONE
410
411		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
412		port routines must be defined elsewhere
413		(i.e. serial_init(), serial_getc(), ...)
414
415		CONFIG_CFB_CONSOLE
416		Enables console device for a color framebuffer. Needs following
417		defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
418			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
419						(default big endian)
420			VIDEO_HW_RECTFILL	graphic chip supports
421						rectangle fill
422						(cf. smiLynxEM)
423			VIDEO_HW_BITBLT		graphic chip supports
424						bit-blit (cf. smiLynxEM)
425			VIDEO_VISIBLE_COLS	visible pixel columns
426						(cols=pitch)
427			VIDEO_VISIBLE_ROWS      visible pixel rows
428			VIDEO_PIXEL_SIZE        bytes per pixel
429			VIDEO_DATA_FORMAT	graphic data format
430						(0-5, cf. cfb_console.c)
431			VIDEO_FB_ADRS           framebuffer address
432			VIDEO_KBD_INIT_FCT	keyboard int fct
433						(i.e. i8042_kbd_init())
434			VIDEO_TSTC_FCT		test char fct
435						(i.e. i8042_tstc)
436			VIDEO_GETC_FCT		get char fct
437						(i.e. i8042_getc)
438			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
439						(requires blink timer
440						cf. i8042.c)
441			CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
442			CONFIG_CONSOLE_TIME	display time/date info in
443						upper right corner
444						(requires CFG_CMD_DATE)
445			CONFIG_VIDEO_LOGO	display Linux logo in
446						upper left corner
447			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
448						linux_logo.h for logo.
449						Requires CONFIG_VIDEO_LOGO
450			CONFIG_CONSOLE_EXTRA_INFO
451						addional board info beside
452						the logo
453
454		When CONFIG_CFB_CONSOLE is defined, video console is
455		default i/o. Serial console can be forced with
456		environment 'console=serial'.
457
458- Console Baudrate:
459		CONFIG_BAUDRATE - in bps
460		Select one of the baudrates listed in
461		CFG_BAUDRATE_TABLE, see below.
462
463- Interrupt driven serial port input:
464		CONFIG_SERIAL_SOFTWARE_FIFO
465
466		PPC405GP only.
467		Use an interrupt handler for receiving data on the
468		serial port. It also enables using hardware handshake
469		(RTS/CTS) and UART's built-in FIFO. Set the number of
470		bytes the interrupt driven input buffer should have.
471
472		Set to 0 to disable this feature (this is the default).
473		This will also disable hardware handshake.
474
475- Console UART Number:
476		CONFIG_UART1_CONSOLE
477
478		IBM PPC4xx only.
479		If defined internal UART1 (and not UART0) is used
480		as default U-Boot console.
481
482- Boot Delay:	CONFIG_BOOTDELAY - in seconds
483		Delay before automatically booting the default image;
484		set to -1 to disable autoboot.
485
486		See doc/README.autoboot for these options that
487		work with CONFIG_BOOTDELAY. None are required.
488		CONFIG_BOOT_RETRY_TIME
489		CONFIG_BOOT_RETRY_MIN
490		CONFIG_AUTOBOOT_KEYED
491		CONFIG_AUTOBOOT_PROMPT
492		CONFIG_AUTOBOOT_DELAY_STR
493		CONFIG_AUTOBOOT_STOP_STR
494		CONFIG_AUTOBOOT_DELAY_STR2
495		CONFIG_AUTOBOOT_STOP_STR2
496		CONFIG_ZERO_BOOTDELAY_CHECK
497		CONFIG_RESET_TO_RETRY
498
499- Autoboot Command:
500		CONFIG_BOOTCOMMAND
501		Only needed when CONFIG_BOOTDELAY is enabled;
502		define a command string that is automatically executed
503		when no character is read on the console interface
504		within "Boot Delay" after reset.
505
506		CONFIG_BOOTARGS
507		This can be used to pass arguments to the bootm
508		command. The value of CONFIG_BOOTARGS goes into the
509		environment value "bootargs".
510
511		CONFIG_RAMBOOT and CONFIG_NFSBOOT
512		The value of these goes into the environment as
513		"ramboot" and "nfsboot" respectively, and can be used
514		as a convenience, when switching between booting from
515		ram and nfs.
516
517- Pre-Boot Commands:
518		CONFIG_PREBOOT
519
520		When this option is #defined, the existence of the
521		environment variable "preboot" will be checked
522		immediately before starting the CONFIG_BOOTDELAY
523		countdown and/or running the auto-boot command resp.
524		entering interactive mode.
525
526		This feature is especially useful when "preboot" is
527		automatically generated or modified. For an example
528		see the LWMON board specific code: here "preboot" is
529		modified when the user holds down a certain
530		combination of keys on the (special) keyboard when
531		booting the systems
532
533- Serial Download Echo Mode:
534		CONFIG_LOADS_ECHO
535		If defined to 1, all characters received during a
536		serial download (using the "loads" command) are
537		echoed back. This might be needed by some terminal
538		emulations (like "cu"), but may as well just take
539		time on others. This setting #define's the initial
540		value of the "loads_echo" environment variable.
541
542- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
543		CONFIG_KGDB_BAUDRATE
544		Select one of the baudrates listed in
545		CFG_BAUDRATE_TABLE, see below.
546
547- Monitor Functions:
548		CONFIG_COMMANDS
549		Most monitor functions can be selected (or
550		de-selected) by adjusting the definition of
551		CONFIG_COMMANDS; to select individual functions,
552		#define CONFIG_COMMANDS by "OR"ing any of the
553		following values:
554
555		#define enables commands:
556		-------------------------
557		CFG_CMD_ASKENV	* ask for env variable
558		CFG_CMD_BDI	  bdinfo
559		CFG_CMD_BEDBUG	  Include BedBug Debugger
560		CFG_CMD_BOOTD	  bootd
561		CFG_CMD_CACHE	  icache, dcache
562		CFG_CMD_CONSOLE	  coninfo
563		CFG_CMD_DATE	* support for RTC, date/time...
564		CFG_CMD_DHCP	  DHCP support
565		CFG_CMD_ECHO	* echo arguments
566		CFG_CMD_EEPROM	* EEPROM read/write support
567		CFG_CMD_ELF	  bootelf, bootvx
568		CFG_CMD_ENV	  saveenv
569		CFG_CMD_FDC	* Floppy Disk Support
570		CFG_CMD_FAT	  FAT partition support
571		CFG_CMD_FDOS	* Dos diskette Support
572		CFG_CMD_FLASH	  flinfo, erase, protect
573		CFG_CMD_FPGA	  FPGA device initialization support
574		CFG_CMD_I2C	* I2C serial bus support
575		CFG_CMD_IDE	* IDE harddisk support
576		CFG_CMD_IMI	  iminfo
577		CFG_CMD_IMMAP	* IMMR dump support
578		CFG_CMD_IRQ	* irqinfo
579		CFG_CMD_KGDB	* kgdb
580		CFG_CMD_LOADB	  loadb
581		CFG_CMD_LOADS	  loads
582		CFG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
583				  loop, mtest
584		CFG_CMD_MMC	  MMC memory mapped support
585		CFG_CMD_MII	  MII utility commands
586		CFG_CMD_NET	  bootp, tftpboot, rarpboot
587		CFG_CMD_PCI	* pciinfo
588		CFG_CMD_PCMCIA	* PCMCIA support
589		CFG_CMD_REGINFO * Register dump
590		CFG_CMD_RUN	  run command in env variable
591		CFG_CMD_SCSI	* SCSI Support
592		CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
593		CFG_CMD_SPI	* SPI serial bus support
594		CFG_CMD_USB	* USB support
595		CFG_CMD_BSP	* Board SPecific functions
596		-----------------------------------------------
597		CFG_CMD_ALL	all
598
599		CFG_CMD_DFL	Default configuration; at the moment
600				this is includes all commands, except
601				the ones marked with "*" in the list
602				above.
603
604		If you don't define CONFIG_COMMANDS it defaults to
605		CFG_CMD_DFL in include/cmd_confdefs.h. A board can
606		override the default settings in the respective
607		include file.
608
609		EXAMPLE: If you want all functions except of network
610		support you can write:
611
612		#define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
613
614
615	Note:	Don't enable the "icache" and "dcache" commands
616		(configuration option CFG_CMD_CACHE) unless you know
617		what you (and your U-Boot users) are doing. Data
618		cache cannot be enabled on systems like the 8xx or
619		8260 (where accesses to the IMMR region must be
620		uncached), and it cannot be disabled on all other
621		systems where we (mis-) use the data cache to hold an
622		initial stack and some data.
623
624
625		XXX - this list needs to get updated!
626
627- Watchdog:
628		CONFIG_WATCHDOG
629		If this variable is defined, it enables watchdog
630		support. There must support in the platform specific
631		code for a watchdog. For the 8xx and 8260 CPUs, the
632		SIU Watchdog feature is enabled in the SYPCR
633		register.
634
635- U-Boot Version:
636		CONFIG_VERSION_VARIABLE
637		If this variable is defined, an environment variable
638		named "ver" is created by U-Boot showing the U-Boot
639		version as printed by the "version" command.
640		This variable is readonly.
641
642- Real-Time Clock:
643
644		When CFG_CMD_DATE is selected, the type of the RTC
645		has to be selected, too. Define exactly one of the
646		following options:
647
648		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
649		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
650		CONFIG_RTC_MC146818	- use MC146818 RTC
651		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
652		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
653		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
654		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
655
656		Note that if the RTC uses I2C, then the I2C interface
657		must also be configured. See I2C Support, below.
658
659- Timestamp Support:
660
661		When CONFIG_TIMESTAMP is selected, the timestamp
662		(date and time) of an image is printed by image
663		commands like bootm or iminfo. This option is
664		automatically enabled when you select CFG_CMD_DATE .
665
666- Partition Support:
667		CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
668		and/or CONFIG_ISO_PARTITION
669
670		If IDE or SCSI support	is  enabled  (CFG_CMD_IDE  or
671		CFG_CMD_SCSI) you must configure support for at least
672		one partition type as well.
673
674- IDE Reset method:
675		CONFIG_IDE_RESET_ROUTINE
676
677		Set this to define that instead of a reset Pin, the
678		routine ide_set_reset(int idereset) will be used.
679
680- ATAPI Support:
681		CONFIG_ATAPI
682
683		Set this to enable ATAPI support.
684
685- SCSI Support:
686		At the moment only there is only support for the
687		SYM53C8XX SCSI controller; define
688		CONFIG_SCSI_SYM53C8XX to enable it.
689
690		CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
691		CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
692		CFG_SCSI_MAX_LUN] can be adjusted to define the
693		maximum numbers of LUNs, SCSI ID's and target
694		devices.
695		CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
696
697- NETWORK Support (PCI):
698		CONFIG_E1000
699		Support for Intel 8254x gigabit chips.
700
701		CONFIG_EEPRO100
702		Support for Intel 82557/82559/82559ER chips.
703		Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
704		write routine for first time initialisation.
705
706		CONFIG_TULIP
707		Support for Digital 2114x chips.
708		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
709		modem chip initialisation (KS8761/QS6611).
710
711		CONFIG_NATSEMI
712		Support for National dp83815 chips.
713
714		CONFIG_NS8382X
715		Support for National dp8382[01] gigabit chips.
716
717- NETWORK Support (other):
718
719		CONFIG_DRIVER_LAN91C96
720		Support for SMSC's LAN91C96 chips.
721
722			CONFIG_LAN91C96_BASE
723			Define this to hold the physical address
724			of the LAN91C96's I/O space
725
726			CONFIG_LAN91C96_USE_32_BIT
727			Define this to enable 32 bit addressing
728
729- USB Support:
730		At the moment only the UHCI host controller is
731		supported (PIP405, MIP405); define
732		CONFIG_USB_UHCI to enable it.
733		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
734		end define CONFIG_USB_STORAGE to enable the USB
735		storage devices.
736		Note:
737		Supported are USB Keyboards and USB Floppy drives
738		(TEAC FD-05PUB).
739
740- MMC Support:
741		The MMC controller on the Intel PXA is supported. To
742		enable this define CONFIG_MMC. The MMC can be
743		accessed from the boot prompt by mapping the device
744		to physical memory similar to flash. Command line is
745		enabled with CFG_CMD_MMC. The MMC driver also works with
746		the FAT fs. This is enabled with CFG_CMD_FAT.
747
748- Keyboard Support:
749		CONFIG_ISA_KEYBOARD
750
751		Define this to enable standard (PC-Style) keyboard
752		support
753
754		CONFIG_I8042_KBD
755		Standard PC keyboard driver with US (is default) and
756		GERMAN key layout (switch via environment 'keymap=de') support.
757		Export function i8042_kbd_init, i8042_tstc and i8042_getc
758		for cfb_console. Supports cursor blinking.
759
760- Video support:
761		CONFIG_VIDEO
762
763		Define this to enable video support (for output to
764		video).
765
766		CONFIG_VIDEO_CT69000
767
768		Enable Chips & Technologies 69000 Video chip
769
770		CONFIG_VIDEO_SMI_LYNXEM
771		Enable Silicon Motion SMI 712/710/810 Video chip
772		Videomode are selected via environment 'videomode' with
773		standard LiLo mode numbers.
774		Following modes are supported  (* is default):
775
776			    800x600  1024x768  1280x1024
777	      256  (8bit)     303*      305       307
778	    65536 (16bit)     314       317       31a
779	16,7 Mill (24bit)     315       318       31b
780		(i.e. setenv videomode 317; saveenv; reset;)
781
782		CONFIG_VIDEO_SED13806
783		Enable Epson SED13806 driver. This driver supports 8bpp
784		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
785		or CONFIG_VIDEO_SED13806_16BPP
786
787- Keyboard Support:
788		CONFIG_KEYBOARD
789
790		Define this to enable a custom keyboard support.
791		This simply calls drv_keyboard_init() which must be
792		defined in your board-specific files.
793		The only board using this so far is RBC823.
794
795- LCD Support:	CONFIG_LCD
796
797		Define this to enable LCD support (for output to LCD
798		display); also select one of the supported displays
799		by defining one of these:
800
801		CONFIG_NEC_NL6648AC33:
802
803			NEC NL6648AC33-18. Active, color, single scan.
804
805		CONFIG_NEC_NL6648BC20
806
807			NEC NL6648BC20-08. 6.5", 640x480.
808			Active, color, single scan.
809
810		CONFIG_SHARP_16x9
811
812			Sharp 320x240. Active, color, single scan.
813			It isn't 16x9, and I am not sure what it is.
814
815		CONFIG_SHARP_LQ64D341
816
817			Sharp LQ64D341 display, 640x480.
818			Active, color, single scan.
819
820		CONFIG_HLD1045
821
822			HLD1045 display, 640x480.
823			Active, color, single scan.
824
825		CONFIG_OPTREX_BW
826
827			Optrex	 CBL50840-2 NF-FW 99 22 M5
828			or
829			Hitachi	 LMG6912RPFC-00T
830			or
831			Hitachi	 SP14Q002
832
833			320x240. Black & white.
834
835		Normally display is black on white background; define
836		CFG_WHITE_ON_BLACK to get it inverted.
837
838- Spash Screen Support: CONFIG_SPLASH_SCREEN
839
840		If this option is set, the environment is checked for
841		a variable "splashimage". If found, the usual display
842		of logo, copyright and system information on the LCD
843		is supressed and the BMP image at the address
844		specified in "splashimage" is loaded instead. The
845		console is redirected to the "nulldev", too. This
846		allows for a "silent" boot where a splash screen is
847		loaded very quickly after power-on.
848
849
850- Ethernet address:
851		CONFIG_ETHADDR
852		CONFIG_ETH2ADDR
853		CONFIG_ETH3ADDR
854
855		Define a default value for ethernet address to use
856		for the respective ethernet interface, in case this
857		is not determined automatically.
858
859- IP address:
860		CONFIG_IPADDR
861
862		Define a default value for the IP address to use for
863		the default ethernet interface, in case this is not
864		determined through e.g. bootp.
865
866- Server IP address:
867		CONFIG_SERVERIP
868
869		Defines a default value for theIP address of a TFTP
870		server to contact when using the "tftboot" command.
871
872- BOOTP Recovery Mode:
873		CONFIG_BOOTP_RANDOM_DELAY
874
875		If you have many targets in a network that try to
876		boot using BOOTP, you may want to avoid that all
877		systems send out BOOTP requests at precisely the same
878		moment (which would happen for instance at recovery
879		from a power failure, when all systems will try to
880		boot, thus flooding the BOOTP server. Defining
881		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
882		inserted before sending out BOOTP requests. The
883		following delays are insterted then:
884
885		1st BOOTP request:	delay 0 ... 1 sec
886		2nd BOOTP request:	delay 0 ... 2 sec
887		3rd BOOTP request:	delay 0 ... 4 sec
888		4th and following
889		BOOTP requests:		delay 0 ... 8 sec
890
891- Status LED:	CONFIG_STATUS_LED
892
893		Several configurations allow to display the current
894		status using a LED. For instance, the LED will blink
895		fast while running U-Boot code, stop blinking as
896		soon as a reply to a BOOTP request was received, and
897		start blinking slow once the Linux kernel is running
898		(supported by a status LED driver in the Linux
899		kernel). Defining CONFIG_STATUS_LED enables this
900		feature in U-Boot.
901
902- CAN Support:	CONFIG_CAN_DRIVER
903
904		Defining CONFIG_CAN_DRIVER enables CAN driver support
905		on those systems that support this (optional)
906		feature, like the TQM8xxL modules.
907
908- I2C Support:	CONFIG_HARD_I2C | CONFIG_SOFT_I2C
909
910		These enable I2C serial bus commands. Defining either of
911		(but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
912		include the appropriate I2C driver for the selected cpu.
913
914		This will allow you to use i2c commands at the u-boot
915		command line (as long as you set CFG_CMD_I2C in
916		CONFIG_COMMANDS) and communicate with i2c based realtime
917		clock chips. See common/cmd_i2c.c for a description of the
918		command line interface.
919
920		CONFIG_HARD_I2C	selects the CPM hardware driver for I2C.
921
922		CONFIG_SOFT_I2C configures u-boot to use a software (aka
923		bit-banging) driver instead of CPM or similar hardware
924		support for I2C.
925
926		There are several other quantities that must also be
927		defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
928
929		In both cases you will need to define CFG_I2C_SPEED
930		to be the frequency (in Hz) at which you wish your i2c bus
931		to run and CFG_I2C_SLAVE to be the address of this node (ie
932		the cpu's i2c node address).
933
934		Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
935		sets the cpu up as a master node and so its address should
936		therefore be cleared to 0 (See, eg, MPC823e User's Manual
937		p.16-473). So, set CFG_I2C_SLAVE to 0.
938
939		That's all that's required for CONFIG_HARD_I2C.
940
941		If you use the software i2c interface (CONFIG_SOFT_I2C)
942		then the following macros need to be defined (examples are
943		from include/configs/lwmon.h):
944
945		I2C_INIT
946
947		(Optional). Any commands necessary to enable the I2C
948		controller or configure ports.
949
950		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=  PB_SCL)
951
952		I2C_PORT
953
954		(Only for MPC8260 CPU). The I/O port to use (the code
955		assumes both bits are on the same port). Valid values
956		are 0..3 for ports A..D.
957
958		I2C_ACTIVE
959
960		The code necessary to make the I2C data line active
961		(driven).  If the data line is open collector, this
962		define can be null.
963
964		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
965
966		I2C_TRISTATE
967
968		The code necessary to make the I2C data line tri-stated
969		(inactive).  If the data line is open collector, this
970		define can be null.
971
972		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
973
974		I2C_READ
975
976		Code that returns TRUE if the I2C data line is high,
977		FALSE if it is low.
978
979		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
980
981		I2C_SDA(bit)
982
983		If <bit> is TRUE, sets the I2C data line high. If it
984		is FALSE, it clears it (low).
985
986		eg: #define I2C_SDA(bit) \
987		         if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
988		         else    immr->im_cpm.cp_pbdat &= ~PB_SDA
989
990		I2C_SCL(bit)
991
992		If <bit> is TRUE, sets the I2C clock line high. If it
993		is FALSE, it clears it (low).
994
995		eg: #define I2C_SCL(bit) \
996		         if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
997		         else    immr->im_cpm.cp_pbdat &= ~PB_SCL
998
999		I2C_DELAY
1000
1001		This delay is invoked four times per clock cycle so this
1002		controls the rate of data transfer.  The data rate thus
1003		is 1 / (I2C_DELAY * 4). Often defined to be something
1004		like:
1005
1006		#define I2C_DELAY  udelay(2)
1007
1008		CFG_I2C_INIT_BOARD
1009
1010		When a board is reset during an i2c bus transfer
1011		chips might think that the current transfer is still
1012		in progress. On some boards it is possible to access
1013		the i2c SCLK line directly, either by using the
1014		processor pin as a GPIO or by having a second pin
1015		connected to the bus. If this option is defined a
1016		custom i2c_init_board() routine in boards/xxx/board.c
1017		is run early in the boot sequence.
1018
1019- SPI Support:	CONFIG_SPI
1020
1021		Enables SPI driver (so far only tested with
1022		SPI EEPROM, also an instance works with Crystal A/D and
1023		D/As on the SACSng board)
1024
1025		CONFIG_SPI_X
1026
1027		Enables extended (16-bit) SPI EEPROM addressing.
1028		(symmetrical to CONFIG_I2C_X)
1029
1030		CONFIG_SOFT_SPI
1031
1032		Enables a software (bit-bang) SPI driver rather than
1033		using hardware support. This is a general purpose
1034		driver that only requires three general I/O port pins
1035		(two outputs, one input) to function. If this is
1036		defined, the board configuration must define several
1037		SPI configuration items (port pins to use, etc). For
1038		an example, see include/configs/sacsng.h.
1039
1040- FPGA Support: CONFIG_FPGA_COUNT
1041
1042		Specify the number of FPGA devices to support.
1043
1044		CONFIG_FPGA
1045
1046		Used to specify the types of FPGA devices. For
1047		example,
1048		#define CONFIG_FPGA  CFG_XILINX_VIRTEX2
1049
1050		CFG_FPGA_PROG_FEEDBACK
1051
1052		Enable printing of hash marks during FPGA
1053		configuration.
1054
1055		CFG_FPGA_CHECK_BUSY
1056
1057		Enable checks on FPGA configuration interface busy
1058		status by the configuration function. This option
1059		will require a board or device specific function to
1060		be written.
1061
1062		CONFIG_FPGA_DELAY
1063
1064		If defined, a function that provides delays in the
1065		FPGA configuration driver.
1066
1067		CFG_FPGA_CHECK_CTRLC
1068
1069		Allow Control-C to interrupt FPGA configuration
1070
1071		CFG_FPGA_CHECK_ERROR
1072
1073		Check for configuration errors during FPGA bitfile
1074		loading. For example, abort during Virtex II
1075		configuration if the INIT_B line goes low (which
1076		indicated a CRC error).
1077
1078		CFG_FPGA_WAIT_INIT
1079
1080		Maximum time to wait for the INIT_B line to deassert
1081		after PROB_B has been deasserted during a Virtex II
1082		FPGA configuration sequence. The default time is 500 mS.
1083
1084		CFG_FPGA_WAIT_BUSY
1085
1086		Maximum time to wait for BUSY to deassert during
1087		Virtex II FPGA configuration. The default is 5 mS.
1088
1089		CFG_FPGA_WAIT_CONFIG
1090
1091		Time to wait after FPGA configuration. The default is
1092		200 mS.
1093
1094- FPGA Support:	CONFIG_FPGA_COUNT
1095
1096		Specify the number of FPGA devices to support.
1097
1098		CONFIG_FPGA
1099
1100		Used to specify the types of FPGA devices.  For example,
1101		#define CONFIG_FPGA  CFG_XILINX_VIRTEX2
1102
1103		CFG_FPGA_PROG_FEEDBACK
1104
1105		Enable printing of hash marks during FPGA configuration.
1106
1107		CFG_FPGA_CHECK_BUSY
1108
1109		Enable checks on FPGA configuration interface busy
1110		status by the configuration function. This option
1111		will require a board or device specific function to
1112		be written.
1113
1114		CONFIG_FPGA_DELAY
1115
1116		If defined, a function that provides delays in the FPGA
1117		configuration driver.
1118
1119		CFG_FPGA_CHECK_CTRLC
1120		Allow Control-C to interrupt FPGA configuration
1121
1122		CFG_FPGA_CHECK_ERROR
1123
1124		Check for configuration errors during FPGA bitfile
1125		loading. For example, abort during Virtex II
1126		configuration if the INIT_B line goes low (which
1127		indicated a CRC error).
1128
1129		CFG_FPGA_WAIT_INIT
1130
1131		Maximum time to wait for the INIT_B line to deassert
1132		after PROB_B has been deasserted during a Virtex II
1133		FPGA configuration sequence. The default time is 500
1134		mS.
1135
1136		CFG_FPGA_WAIT_BUSY
1137
1138		Maximum time to wait for BUSY to deassert during
1139		Virtex II FPGA configuration. The default is 5 mS.
1140
1141		CFG_FPGA_WAIT_CONFIG
1142
1143		Time to wait after FPGA configuration. The default is
1144		200 mS.
1145
1146- Configuration Management:
1147		CONFIG_IDENT_STRING
1148
1149		If defined, this string will be added to the U-Boot
1150		version information (U_BOOT_VERSION)
1151
1152- Vendor Parameter Protection:
1153
1154		U-Boot considers the values of the environment
1155		variables "serial#" (Board Serial Number) and
1156		"ethaddr" (Ethernet Address) to bb parameters that
1157		are set once by the board vendor / manufacturer, and
1158		protects these variables from casual modification by
1159		the user. Once set, these variables are read-only,
1160		and write or delete attempts are rejected. You can
1161		change this behviour:
1162
1163		If CONFIG_ENV_OVERWRITE is #defined in your config
1164		file, the write protection for vendor parameters is
1165		completely disabled. Anybody can change or delete
1166		these parameters.
1167
1168		Alternatively, if you #define _both_ CONFIG_ETHADDR
1169		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1170		ethernet address is installed in the environment,
1171		which can be changed exactly ONCE by the user. [The
1172		serial# is unaffected by this, i. e. it remains
1173		read-only.]
1174
1175- Protected RAM:
1176		CONFIG_PRAM
1177
1178		Define this variable to enable the reservation of
1179		"protected RAM", i. e. RAM which is not overwritten
1180		by U-Boot. Define CONFIG_PRAM to hold the number of
1181		kB you want to reserve for pRAM. You can overwrite
1182		this default value by defining an environment
1183		variable "pram" to the number of kB you want to
1184		reserve. Note that the board info structure will
1185		still show the full amount of RAM. If pRAM is
1186		reserved, a new environment variable "mem" will
1187		automatically be defined to hold the amount of
1188		remaining RAM in a form that can be passed as boot
1189		argument to Linux, for instance like that:
1190
1191			setenv bootargs ... mem=\$(mem)
1192			saveenv
1193
1194		This way you can tell Linux not to use this memory,
1195		either, which results in a memory region that will
1196		not be affected by reboots.
1197
1198		*WARNING* If your board configuration uses automatic
1199		detection of the RAM size, you must make sure that
1200		this memory test is non-destructive. So far, the
1201		following board configurations are known to be
1202		"pRAM-clean":
1203
1204			ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1205			HERMES, IP860, RPXlite, LWMON, LANTEC,
1206			PCU_E, FLAGADM, TQM8260
1207
1208- Error Recovery:
1209		CONFIG_PANIC_HANG
1210
1211		Define this variable to stop the system in case of a
1212		fatal error, so that you have to reset it manually.
1213		This is probably NOT a good idea for an embedded
1214		system where you want to system to reboot
1215		automatically as fast as possible, but it may be
1216		useful during development since you can try to debug
1217		the conditions that lead to the situation.
1218
1219		CONFIG_NET_RETRY_COUNT
1220
1221		This variable defines the number of retries for
1222		network operations like ARP, RARP, TFTP, or BOOTP
1223		before giving up the operation. If not defined, a
1224		default value of 5 is used.
1225
1226- Command Interpreter:
1227		CFG_HUSH_PARSER
1228
1229		Define this variable to enable the "hush" shell (from
1230		Busybox) as command line interpreter, thus enabling
1231		powerful command line syntax like
1232		if...then...else...fi conditionals or `&&' and '||'
1233		constructs ("shell scripts").
1234
1235		If undefined, you get the old, much simpler behaviour
1236		with a somewhat smaller memory footprint.
1237
1238
1239		CFG_PROMPT_HUSH_PS2
1240
1241		This defines the secondary prompt string, which is
1242		printed when the command interpreter needs more input
1243		to complete a command. Usually "> ".
1244
1245	Note:
1246
1247		In the current implementation, the local variables
1248		space and global environment variables space are
1249		separated. Local variables are those you define by
1250		simply typing `name=value'. To access a local
1251		variable later on, you have write `$name' or
1252		`${name}'; to execute the contents of a variable
1253		directly type `$name' at the command prompt.
1254
1255		Global environment variables are those you use
1256		setenv/printenv to work with. To run a command stored
1257		in such a variable, you need to use the run command,
1258		and you must not use the '$' sign to access them.
1259
1260		To store commands and special characters in a
1261		variable, please use double quotation marks
1262		surrounding the whole text of the variable, instead
1263		of the backslashes before semicolons and special
1264		symbols.
1265
1266- Default Environment
1267		CONFIG_EXTRA_ENV_SETTINGS
1268
1269		Define this to contain any number of null terminated
1270		strings (variable = value pairs) that will be part of
1271		the default enviroment compiled into the boot image.
1272
1273		For example, place something like this in your
1274		board's config file:
1275
1276		#define CONFIG_EXTRA_ENV_SETTINGS \
1277			"myvar1=value1\0" \
1278			"myvar2=value2\0"
1279
1280		Warning: This method is based on knowledge about the
1281		internal format how the environment is stored by the
1282		U-Boot code. This is NOT an official, exported
1283		interface! Although it is unlikely that this format
1284		will change soon, but there is no guarantee either.
1285		You better know what you are doing here.
1286
1287		Note: overly (ab)use of the default environment is
1288		discouraged. Make sure to check other ways to preset
1289		the environment like the autoscript function or the
1290		boot command first.
1291
1292- DataFlash Support
1293		CONFIG_HAS_DATAFLASH
1294
1295		Defining this option enables DataFlash features and
1296		allows to read/write in Dataflash via the standard
1297		commands cp, md...
1298
1299- Show boot progress
1300		CONFIG_SHOW_BOOT_PROGRESS
1301
1302		Defining this option allows to add some board-
1303		specific code (calling a user-provided function
1304		"show_boot_progress(int)") that enables you to show
1305		the system's boot progress on some display (for
1306		example, some LED's) on your board. At the moment,
1307		the following checkpoints are implemented:
1308
1309  Arg	Where			When
1310    1	common/cmd_bootm.c	before attempting to boot an image
1311   -1	common/cmd_bootm.c	Image header has bad     magic number
1312    2	common/cmd_bootm.c	Image header has correct magic number
1313   -2	common/cmd_bootm.c	Image header has bad     checksum
1314    3	common/cmd_bootm.c	Image header has correct checksum
1315   -3	common/cmd_bootm.c	Image data   has bad     checksum
1316    4	common/cmd_bootm.c	Image data   has correct checksum
1317   -4	common/cmd_bootm.c	Image is for unsupported architecture
1318    5	common/cmd_bootm.c	Architecture check OK
1319   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi, standalone)
1320    6	common/cmd_bootm.c	Image Type check OK
1321   -6	common/cmd_bootm.c	gunzip uncompression error
1322   -7	common/cmd_bootm.c	Unimplemented compression type
1323    7	common/cmd_bootm.c	Uncompression OK
1324   -8	common/cmd_bootm.c	Wrong Image Type (not kernel, multi, standalone)
1325    8	common/cmd_bootm.c	Image Type check OK
1326   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
1327    9	common/cmd_bootm.c	Start initial ramdisk verification
1328  -10	common/cmd_bootm.c	Ramdisk header has bad     magic number
1329  -11	common/cmd_bootm.c	Ramdisk header has bad     checksum
1330   10	common/cmd_bootm.c	Ramdisk header is OK
1331  -12	common/cmd_bootm.c	Ramdisk data   has bad     checksum
1332   11	common/cmd_bootm.c	Ramdisk data   has correct checksum
1333   12	common/cmd_bootm.c	Ramdisk verification complete, start loading
1334  -13	common/cmd_bootm.c	Wrong Image Type (not PPC Linux Ramdisk)
1335   13	common/cmd_bootm.c	Start multifile image verification
1336   14	common/cmd_bootm.c	No initial ramdisk, no multifile, continue.
1337   15	common/cmd_bootm.c	All preparation done, transferring control to OS
1338
1339   -1	common/cmd_doc.c	Bad usage of "doc" command
1340   -1	common/cmd_doc.c	No boot device
1341   -1	common/cmd_doc.c	Unknown Chip ID on boot device
1342   -1	common/cmd_doc.c	Read Error on boot device
1343   -1	common/cmd_doc.c	Image header has bad magic number
1344
1345   -1	common/cmd_ide.c	Bad usage of "ide" command
1346   -1	common/cmd_ide.c	No boot device
1347   -1	common/cmd_ide.c	Unknown boot device
1348   -1	common/cmd_ide.c	Unknown partition table
1349   -1	common/cmd_ide.c	Invalid partition type
1350   -1	common/cmd_ide.c	Read Error on boot device
1351   -1	common/cmd_ide.c	Image header has bad magic number
1352
1353   -1	common/cmd_nvedit.c	Environment not changable, but has bad CRC
1354
1355
1356Modem Support:
1357--------------
1358
1359[so far only for SMDK2400 and TRAB boards]
1360
1361- Modem support endable:
1362		CONFIG_MODEM_SUPPORT
1363
1364- RTS/CTS Flow control enable:
1365		CONFIG_HWFLOW
1366
1367- Modem debug support:
1368		CONFIG_MODEM_SUPPORT_DEBUG
1369
1370		Enables debugging stuff (char screen[1024], dbg())
1371		for modem support. Useful only with BDI2000.
1372
1373- General:
1374
1375		In the target system modem support is enabled when a
1376		specific key (key combination) is pressed during
1377		power-on. Otherwise U-Boot will boot normally
1378		(autoboot). The key_pressed() fuction is called from
1379		board_init(). Currently key_pressed() is a dummy
1380		function, returning 1 and thus enabling modem
1381		initialization.
1382
1383		If there are no modem init strings in the
1384		environment, U-Boot proceed to autoboot; the
1385		previous output (banner, info printfs) will be
1386		supressed, though.
1387
1388		See also: doc/README.Modem
1389
1390
1391Configuration Settings:
1392-----------------------
1393
1394- CFG_LONGHELP: Defined when you want long help messages included;
1395		undefine this when you're short of memory.
1396
1397- CFG_PROMPT:	This is what U-Boot prints on the console to
1398		prompt for user input.
1399
1400- CFG_CBSIZE:	Buffer size for input from the Console
1401
1402- CFG_PBSIZE:	Buffer size for Console output
1403
1404- CFG_MAXARGS:	max. Number of arguments accepted for monitor commands
1405
1406- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1407		the application (usually a Linux kernel) when it is
1408		booted
1409
1410- CFG_BAUDRATE_TABLE:
1411		List of legal baudrate settings for this board.
1412
1413- CFG_CONSOLE_INFO_QUIET
1414		Suppress display of console information at boot.
1415
1416- CFG_CONSOLE_IS_IN_ENV
1417		If the board specific function
1418			extern int overwrite_console (void);
1419		returns 1, the stdin, stderr and stdout are switched to the
1420		serial port, else the settings in the environment are used.
1421
1422- CFG_CONSOLE_OVERWRITE_ROUTINE
1423		Enable the call to overwrite_console().
1424
1425- CFG_CONSOLE_ENV_OVERWRITE
1426		Enable overwrite of previous console environment settings.
1427
1428- CFG_MEMTEST_START, CFG_MEMTEST_END:
1429		Begin and End addresses of the area used by the
1430		simple memory test.
1431
1432- CFG_ALT_MEMTEST:
1433		Enable an alternate, more extensive memory test.
1434
1435- CFG_TFTP_LOADADDR:
1436		Default load address for network file downloads
1437
1438- CFG_LOADS_BAUD_CHANGE:
1439		Enable temporary baudrate change while serial download
1440
1441- CFG_SDRAM_BASE:
1442		Physical start address of SDRAM. _Must_ be 0 here.
1443
1444- CFG_MBIO_BASE:
1445		Physical start address of Motherboard I/O (if using a
1446		Cogent motherboard)
1447
1448- CFG_FLASH_BASE:
1449		Physical start address of Flash memory.
1450
1451- CFG_MONITOR_BASE:
1452		Physical start address of boot monitor code (set by
1453		make config files to be same as the text base address
1454		(TEXT_BASE) used when linking) - same as
1455		CFG_FLASH_BASE when booting from flash.
1456
1457- CFG_MONITOR_LEN:
1458		Size of memory reserved for monitor code, used to
1459		determine _at_compile_time_ (!) if the environment is
1460		embedded within the U-Boot image, or in a separate
1461		flash sector.
1462
1463- CFG_MALLOC_LEN:
1464		Size of DRAM reserved for malloc() use.
1465
1466- CFG_BOOTMAPSZ:
1467		Maximum size of memory mapped by the startup code of
1468		the Linux kernel; all data that must be processed by
1469		the Linux kernel (bd_info, boot arguments, eventually
1470		initrd image) must be put below this limit.
1471
1472- CFG_MAX_FLASH_BANKS:
1473		Max number of Flash memory banks
1474
1475- CFG_MAX_FLASH_SECT:
1476		Max number of sectors on a Flash chip
1477
1478- CFG_FLASH_ERASE_TOUT:
1479		Timeout for Flash erase operations (in ms)
1480
1481- CFG_FLASH_WRITE_TOUT:
1482		Timeout for Flash write operations (in ms)
1483
1484- CFG_FLASH_LOCK_TOUT
1485		Timeout for Flash set sector lock bit operation (in ms)
1486
1487- CFG_FLASH_UNLOCK_TOUT
1488		Timeout for Flash clear lock bits operation (in ms)
1489
1490- CFG_FLASH_PROTECTION
1491		If defined, hardware flash sectors protection is used
1492		instead of U-Boot software protection.
1493
1494- CFG_DIRECT_FLASH_TFTP:
1495
1496		Enable TFTP transfers directly to flash memory;
1497		without this option such a download has to be
1498		performed in two steps: (1) download to RAM, and (2)
1499		copy from RAM to flash.
1500
1501		The two-step approach is usually more reliable, since
1502		you can check if the download worked before you erase
1503		the flash, but in some situations (when sytem RAM is
1504		too limited to allow for a tempory copy of the
1505		downloaded image) this option may be very useful.
1506
1507- CFG_FLASH_CFI:
1508		Define if the flash driver uses extra elements in the
1509		common flash structure for storing flash geometry
1510
1511- CFG_RX_ETH_BUFFER:
1512		Defines the number of ethernet receive buffers. On some
1513		ethernet controllers it is recommended to set this value
1514		to 8 or even higher (EEPRO100 or 405 EMAC), since all
1515		buffers can be full shortly after enabling the interface
1516		on high ethernet traffic.
1517		Defaults to 4 if not defined.
1518
1519The following definitions that deal with the placement and management
1520of environment data (variable area); in general, we support the
1521following configurations:
1522
1523- CFG_ENV_IS_IN_FLASH:
1524
1525	Define this if the environment is in flash memory.
1526
1527	a) The environment occupies one whole flash sector, which is
1528	   "embedded" in the text segment with the U-Boot code. This
1529	   happens usually with "bottom boot sector" or "top boot
1530	   sector" type flash chips, which have several smaller
1531	   sectors at the start or the end. For instance, such a
1532	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1533	   such a case you would place the environment in one of the
1534	   4 kB sectors - with U-Boot code before and after it. With
1535	   "top boot sector" type flash chips, you would put the
1536	   environment in one of the last sectors, leaving a gap
1537	   between U-Boot and the environment.
1538
1539	- CFG_ENV_OFFSET:
1540
1541	   Offset of environment data (variable area) to the
1542	   beginning of flash memory; for instance, with bottom boot
1543	   type flash chips the second sector can be used: the offset
1544	   for this sector is given here.
1545
1546	   CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1547
1548	- CFG_ENV_ADDR:
1549
1550	   This is just another way to specify the start address of
1551	   the flash sector containing the environment (instead of
1552	   CFG_ENV_OFFSET).
1553
1554	- CFG_ENV_SECT_SIZE:
1555
1556	   Size of the sector containing the environment.
1557
1558
1559	b) Sometimes flash chips have few, equal sized, BIG sectors.
1560	   In such a case you don't want to spend a whole sector for
1561	   the environment.
1562
1563	- CFG_ENV_SIZE:
1564
1565	   If you use this in combination with CFG_ENV_IS_IN_FLASH
1566	   and CFG_ENV_SECT_SIZE, you can specify to use only a part
1567	   of this flash sector for the environment. This saves
1568	   memory for the RAM copy of the environment.
1569
1570	   It may also save flash memory if you decide to use this
1571	   when your environment is "embedded" within U-Boot code,
1572	   since then the remainder of the flash sector could be used
1573	   for U-Boot code. It should be pointed out that this is
1574	   STRONGLY DISCOURAGED from a robustness point of view:
1575	   updating the environment in flash makes it always
1576	   necessary to erase the WHOLE sector. If something goes
1577	   wrong before the contents has been restored from a copy in
1578	   RAM, your target system will be dead.
1579
1580	- CFG_ENV_ADDR_REDUND
1581	  CFG_ENV_SIZE_REDUND
1582
1583	   These settings describe a second storage area used to hold
1584	   a redundand copy of the environment data, so that there is
1585	   a valid backup copy in case there is a power failure during
1586	   a "saveenv" operation.
1587
1588BE CAREFUL! Any changes to the flash layout, and some changes to the
1589source code will make it necessary to adapt <board>/u-boot.lds*
1590accordingly!
1591
1592
1593- CFG_ENV_IS_IN_NVRAM:
1594
1595	Define this if you have some non-volatile memory device
1596	(NVRAM, battery buffered SRAM) which you want to use for the
1597	environment.
1598
1599	- CFG_ENV_ADDR:
1600	- CFG_ENV_SIZE:
1601
1602	  These two #defines are used to determin the memory area you
1603	  want to use for environment. It is assumed that this memory
1604	  can just be read and written to, without any special
1605	  provision.
1606
1607BE CAREFUL! The first access to the environment happens quite early
1608in U-Boot initalization (when we try to get the setting of for the
1609console baudrate). You *MUST* have mappend your NVRAM area then, or
1610U-Boot will hang.
1611
1612Please note that even with NVRAM we still use a copy of the
1613environment in RAM: we could work on NVRAM directly, but we want to
1614keep settings there always unmodified except somebody uses "saveenv"
1615to save the current settings.
1616
1617
1618- CFG_ENV_IS_IN_EEPROM:
1619
1620	Use this if you have an EEPROM or similar serial access
1621	device and a driver for it.
1622
1623	- CFG_ENV_OFFSET:
1624	- CFG_ENV_SIZE:
1625
1626	  These two #defines specify the offset and size of the
1627	  environment area within the total memory of your EEPROM.
1628
1629	- CFG_I2C_EEPROM_ADDR:
1630	  If defined, specified the chip address of the EEPROM device.
1631	  The default address is zero.
1632
1633	- CFG_EEPROM_PAGE_WRITE_BITS:
1634	  If defined, the number of bits used to address bytes in a
1635	  single page in the EEPROM device.  A 64 byte page, for example
1636	  would require six bits.
1637
1638	- CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1639	  If defined, the number of milliseconds to delay between
1640	  page writes.  The default is zero milliseconds.
1641
1642	- CFG_I2C_EEPROM_ADDR_LEN:
1643	  The length in bytes of the EEPROM memory array address.  Note
1644	  that this is NOT the chip address length!
1645
1646	- CFG_EEPROM_SIZE:
1647	  The size in bytes of the EEPROM device.
1648
1649
1650- CFG_SPI_INIT_OFFSET
1651
1652	Defines offset to the initial SPI buffer area in DPRAM. The
1653	area is used at an early stage (ROM part) if the environment
1654	is configured to reside in the SPI EEPROM: We need a 520 byte
1655	scratch DPRAM area. It is used between the two initialization
1656	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1657	to be a good choice since it makes it far enough from the
1658	start of the data area as well as from the stack pointer.
1659
1660Please note that the environment is read-only as long as the monitor
1661has been relocated to RAM and a RAM copy of the environment has been
1662created; also, when using EEPROM you will have to use getenv_r()
1663until then to read environment variables.
1664
1665The environment is protected by a CRC32 checksum. Before the monitor
1666is relocated into RAM, as a result of a bad CRC you will be working
1667with the compiled-in default environment - *silently*!!! [This is
1668necessary, because the first environment variable we need is the
1669"baudrate" setting for the console - if we have a bad CRC, we don't
1670have any device yet where we could complain.]
1671
1672Note: once the monitor has been relocated, then it will complain if
1673the default environment is used; a new CRC is computed as soon as you
1674use the "saveenv" command to store a valid environment.
1675
1676
1677Low Level (hardware related) configuration options:
1678---------------------------------------------------
1679
1680- CFG_CACHELINE_SIZE:
1681		Cache Line Size of the CPU.
1682
1683- CFG_DEFAULT_IMMR:
1684		Default address of the IMMR after system reset.
1685		Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1686		to be able to adjust the position of the IMMR
1687		register after a reset.
1688
1689- Floppy Disk Support:
1690		CFG_FDC_DRIVE_NUMBER
1691
1692		the default drive number (default value 0)
1693
1694		CFG_ISA_IO_STRIDE
1695
1696		defines the spacing between fdc chipset registers
1697		(default value 1)
1698
1699		CFG_ISA_IO_OFFSET
1700
1701		defines the offset of register from address. It
1702		depends on which part of the data bus is connected to
1703		the fdc chipset. (default value 0)
1704
1705		If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1706		CFG_FDC_DRIVE_NUMBER are undefined, they take their
1707		default value.
1708
1709		if CFG_FDC_HW_INIT is defined, then the function
1710		fdc_hw_init() is called at the beginning of the FDC
1711		setup. fdc_hw_init() must be provided by the board
1712		source code. It is used to make hardware dependant
1713		initializations.
1714
1715- CFG_IMMR:	Physical address of the Internal Memory Mapped
1716		Register; DO NOT CHANGE! (11-4)
1717		[MPC8xx systems only]
1718
1719- CFG_INIT_RAM_ADDR:
1720
1721		Start address of memory area tha can be used for
1722		initial data and stack; please note that this must be
1723		writable memory that is working WITHOUT special
1724		initialization, i. e. you CANNOT use normal RAM which
1725		will become available only after programming the
1726		memory controller and running certain initialization
1727		sequences.
1728
1729		U-Boot uses the following memory types:
1730		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1731		- MPC824X: data cache
1732		- PPC4xx:  data cache
1733
1734- CFG_GBL_DATA_OFFSET:
1735
1736		Offset of the initial data structure in the memory
1737		area defined by CFG_INIT_RAM_ADDR. Usually
1738		CFG_GBL_DATA_OFFSET is chosen such that the initial
1739		data is located at the end of the available space
1740		(sometimes written as (CFG_INIT_RAM_END -
1741		CFG_INIT_DATA_SIZE), and the initial stack is just
1742		below that area (growing from (CFG_INIT_RAM_ADDR +
1743		CFG_GBL_DATA_OFFSET) downward.
1744
1745	Note:
1746		On the MPC824X (or other systems that use the data
1747		cache for initial memory) the address chosen for
1748		CFG_INIT_RAM_ADDR is basically arbitrary - it must
1749		point to an otherwise UNUSED address space between
1750		the top of RAM and the start of the PCI space.
1751
1752- CFG_SIUMCR:	SIU Module Configuration (11-6)
1753
1754- CFG_SYPCR:	System Protection Control (11-9)
1755
1756- CFG_TBSCR:	Time Base Status and Control (11-26)
1757
1758- CFG_PISCR:	Periodic Interrupt Status and Control (11-31)
1759
1760- CFG_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
1761
1762- CFG_SCCR:	System Clock and reset Control Register (15-27)
1763
1764- CFG_OR_TIMING_SDRAM:
1765		SDRAM timing
1766
1767- CFG_MAMR_PTA:
1768		periodic timer for refresh
1769
1770- CFG_DER:	Debug Event Register (37-47)
1771
1772- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1773  CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1774  CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1775  CFG_BR1_PRELIM:
1776		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1777
1778- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1779  CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1780  CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1781		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1782
1783- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1784  CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1785		Machine Mode Register and Memory Periodic Timer
1786		Prescaler definitions (SDRAM timing)
1787
1788- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1789		enable I2C microcode relocation patch (MPC8xx);
1790		define relocation offset in DPRAM [DSP2]
1791
1792- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1793		enable SPI microcode relocation patch (MPC8xx);
1794		define relocation offset in DPRAM [SCC4]
1795
1796- CFG_USE_OSCCLK:
1797		Use OSCM clock mode on MBX8xx board. Be careful,
1798		wrong setting might damage your board. Read
1799		doc/README.MBX before setting this variable!
1800
1801- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1802		Offset of the bootmode word in DPRAM used by post
1803		(Power On Self Tests). This definition overrides
1804		#define'd default value in commproc.h resp.
1805		cpm_8260.h.
1806
1807- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1808  CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1809  CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1810  CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1811  CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1812  CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1813  CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1814  CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1815		Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1816
1817Building the Software:
1818======================
1819
1820Building U-Boot has been tested in native PPC environments (on a
1821PowerBook G3 running LinuxPPC 2000) and in cross environments
1822(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1823NetBSD 1.5 on x86).
1824
1825If you are not using a native PPC environment, it is assumed that you
1826have the GNU cross compiling tools available in your path and named
1827with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1828you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1829the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1830change it to:
1831
1832	CROSS_COMPILE = ppc_4xx-
1833
1834
1835U-Boot is intended to be  simple  to  build.  After  installing  the
1836sources	 you must configure U-Boot for one specific board type. This
1837is done by typing:
1838
1839	make NAME_config
1840
1841where "NAME_config" is the name of one of the existing
1842configurations; the following names are supported:
1843
1844    ADCIOP_config	  GTH_config		TQM850L_config
1845    ADS860_config	  IP860_config		TQM855L_config
1846    AR405_config	  IVML24_config		TQM860L_config
1847    CANBT_config	  IVMS8_config		WALNUT405_config
1848    CPCI405_config	  LANTEC_config		cogent_common_config
1849    CPCIISER4_config	  MBX_config		cogent_mpc8260_config
1850    CU824_config	  MBX860T_config	cogent_mpc8xx_config
1851    ESTEEM192E_config	  RPXlite_config	hermes_config
1852    ETX094_config	  RPXsuper_config	hymod_config
1853    FADS823_config	  SM850_config		lwmon_config
1854    FADS850SAR_config	  SPD823TS_config	pcu_e_config
1855    FADS860T_config	  SXNI855T_config	rsdproto_config
1856    FPS850L_config	  Sandpoint8240_config	sbc8260_config
1857    GENIETV_config	  TQM823L_config	PIP405_config
1858    GEN860T_config	  EBONY_config		FPS860L_config
1859    ELPT860_config	  cmi_mpc5xx_config	NETVIA_config
1860    at91rm9200dk_config
1861
1862Note: for some board special configuration names may exist; check  if
1863      additional  information is available from the board vendor; for
1864      instance, the TQM8xxL systems run normally at 50 MHz and use  a
1865      SCC  for	10baseT	 ethernet; there are also systems with 80 MHz
1866      CPU clock, and an optional Fast Ethernet	module	is  available
1867      for  CPU's  with FEC. You can select such additional "features"
1868      when chosing the configuration, i. e.
1869
1870      make TQM860L_config
1871	- will configure for a plain TQM860L, i. e. 50MHz, no FEC
1872
1873      make TQM860L_FEC_config
1874	- will configure for a TQM860L at 50MHz with FEC for ethernet
1875
1876      make TQM860L_80MHz_config
1877	- will configure for a TQM860L at 80 MHz, with normal 10baseT
1878	  interface
1879
1880      make TQM860L_FEC_80MHz_config
1881	- will configure for a TQM860L at 80 MHz with FEC for ethernet
1882
1883      make TQM823L_LCD_config
1884	- will configure for a TQM823L with U-Boot console on LCD
1885
1886      make TQM823L_LCD_80MHz_config
1887	- will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1888
1889      etc.
1890
1891
1892Finally, type "make all", and you should get some working U-Boot
1893images ready for downlod to / installation on your system:
1894
1895- "u-boot.bin" is a raw binary image
1896- "u-boot" is an image in ELF binary format
1897- "u-boot.srec" is in Motorola S-Record format
1898
1899
1900Please be aware that the Makefiles assume you are using GNU make, so
1901for instance on NetBSD you might need to use "gmake" instead of
1902native "make".
1903
1904
1905If the system board that you have is not listed, then you will need
1906to port U-Boot to your hardware platform. To do this, follow these
1907steps:
1908
19091.  Add a new configuration option for your board to the toplevel
1910    "Makefile" and to the "MAKEALL" script, using the existing
1911    entries as examples. Note that here and at many other places
1912    boards and other names are listed alphabetically sorted. Please
1913    keep this order.
19142.  Create a new directory to hold your board specific code. Add any
1915    files you need. In your board directory, you will need at least
1916    the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
19173.  Create a new configuration file "include/configs/<board>.h" for
1918    your board
19193.  If you're porting U-Boot to a new CPU, then also create a new
1920    directory to hold your CPU specific code. Add any files you need.
19214.  Run "make <board>_config" with your new name.
19225.  Type "make", and you should get a working "u-boot.srec" file
1923    to be installed on your target system.
19246.  Debug and solve any problems that might arise.
1925    [Of course, this last step is much harder than it sounds.]
1926
1927
1928Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1929==============================================================
1930
1931If you have modified U-Boot sources (for instance added a new	board
1932or  support  for  new  devices,	 a new CPU, etc.) you are expected to
1933provide feedback to the other developers. The feedback normally takes
1934the form of a "patch", i. e. a context diff against a certain (latest
1935official or latest in CVS) version of U-Boot sources.
1936
1937But before you submit such a patch, please verify that	your  modifi-
1938cation	did not break existing code. At least make sure that *ALL* of
1939the supported boards compile WITHOUT ANY compiler warnings. To do so,
1940just run the "MAKEALL" script, which will configure and build U-Boot
1941for ALL supported system. Be warned, this will take a while. You  can
1942select	which  (cross)	compiler  to use py passing a `CROSS_COMPILE'
1943environment variable to the script, i. e. to use the cross tools from
1944MontaVista's Hard Hat Linux you can type
1945
1946	CROSS_COMPILE=ppc_8xx- MAKEALL
1947
1948or to build on a native PowerPC system you can type
1949
1950	CROSS_COMPILE=' ' MAKEALL
1951
1952See also "U-Boot Porting Guide" below.
1953
1954
1955Monitor Commands - Overview:
1956============================
1957
1958go	- start application at address 'addr'
1959run	- run commands in an environment variable
1960bootm	- boot application image from memory
1961bootp	- boot image via network using BootP/TFTP protocol
1962tftpboot- boot image via network using TFTP protocol
1963	       and env variables "ipaddr" and "serverip"
1964	       (and eventually "gatewayip")
1965rarpboot- boot image via network using RARP/TFTP protocol
1966diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
1967loads	- load S-Record file over serial line
1968loadb	- load binary file over serial line (kermit mode)
1969md	- memory display
1970mm	- memory modify (auto-incrementing)
1971nm	- memory modify (constant address)
1972mw	- memory write (fill)
1973cp	- memory copy
1974cmp	- memory compare
1975crc32	- checksum calculation
1976imd     - i2c memory display
1977imm     - i2c memory modify (auto-incrementing)
1978inm     - i2c memory modify (constant address)
1979imw     - i2c memory write (fill)
1980icrc32  - i2c checksum calculation
1981iprobe  - probe to discover valid I2C chip addresses
1982iloop   - infinite loop on address range
1983isdram  - print SDRAM configuration information
1984sspi    - SPI utility commands
1985base	- print or set address offset
1986printenv- print environment variables
1987setenv	- set environment variables
1988saveenv - save environment variables to persistent storage
1989protect - enable or disable FLASH write protection
1990erase	- erase FLASH memory
1991flinfo	- print FLASH memory information
1992bdinfo	- print Board Info structure
1993iminfo	- print header information for application image
1994coninfo - print console devices and informations
1995ide	- IDE sub-system
1996loop	- infinite loop on address range
1997mtest	- simple RAM test
1998icache	- enable or disable instruction cache
1999dcache	- enable or disable data cache
2000reset	- Perform RESET of the CPU
2001echo	- echo args to console
2002version - print monitor version
2003help	- print online help
2004?	- alias for 'help'
2005
2006
2007Monitor Commands - Detailed Description:
2008========================================
2009
2010TODO.
2011
2012For now: just type "help <command>".
2013
2014
2015Environment Variables:
2016======================
2017
2018U-Boot supports user configuration using Environment Variables which
2019can be made persistent by saving to Flash memory.
2020
2021Environment Variables are set using "setenv", printed using
2022"printenv", and saved to Flash using "saveenv". Using "setenv"
2023without a value can be used to delete a variable from the
2024environment. As long as you don't save the environment you are
2025working with an in-memory copy. In case the Flash area containing the
2026environment is erased by accident, a default environment is provided.
2027
2028Some configuration options can be set using Environment Variables:
2029
2030  baudrate	- see CONFIG_BAUDRATE
2031
2032  bootdelay	- see CONFIG_BOOTDELAY
2033
2034  bootcmd	- see CONFIG_BOOTCOMMAND
2035
2036  bootargs	- Boot arguments when booting an RTOS image
2037
2038  bootfile	- Name of the image to load with TFTP
2039
2040  autoload	- if set to "no" (any string beginning with 'n'),
2041		  "bootp" will just load perform a lookup of the
2042		  configuration from the BOOTP server, but not try to
2043		  load any image using TFTP
2044
2045  autostart	- if set to "yes", an image loaded using the "bootp",
2046		  "rarpboot", "tftpboot" or "diskboot" commands will
2047		  be automatically started (by internally calling
2048		  "bootm")
2049
2050		  If set to "no", a standalone image passed to the
2051		  "bootm" command will be copied to the load address
2052		  (and eventually uncompressed), but NOT be started.
2053		  This can be used to load and uncompress arbitrary
2054		  data.
2055
2056  initrd_high	- restrict positioning of initrd images:
2057		  If this variable is not set, initrd images will be
2058		  copied to the highest possible address in RAM; this
2059		  is usually what you want since it allows for
2060		  maximum initrd size. If for some reason you want to
2061		  make sure that the initrd image is loaded below the
2062		  CFG_BOOTMAPSZ limit, you can set this environment
2063		  variable to a value of "no" or "off" or "0".
2064		  Alternatively, you can set it to a maximum upper
2065		  address to use (U-Boot will still check that it
2066		  does not overwrite the U-Boot stack and data).
2067
2068		  For instance, when you have a system with 16 MB
2069		  RAM, and want to reseve 4 MB from use by Linux,
2070		  you can do this by adding "mem=12M" to the value of
2071		  the "bootargs" variable. However, now you must make
2072		  sure, that the initrd image is placed in the first
2073		  12 MB as well - this can be done with
2074
2075		  setenv initrd_high 00c00000
2076
2077		  If you set initrd_high to 0xFFFFFFFF, this is an
2078		  indication to U-Boot that all addresses are legal
2079		  for the Linux kernel, including addresses in flash
2080		  memory. In this case U-Boot will NOT COPY the
2081		  ramdisk at all. This may be useful to reduce the
2082		  boot time on your system, but requires that this
2083		  feature is supported by your Linux kernel.
2084
2085  ipaddr	- IP address; needed for tftpboot command
2086
2087  loadaddr	- Default load address for commands like "bootp",
2088		  "rarpboot", "tftpboot", "loadb" or "diskboot"
2089
2090  loads_echo	- see CONFIG_LOADS_ECHO
2091
2092  serverip	- TFTP server IP address; needed for tftpboot command
2093
2094  bootretry	- see CONFIG_BOOT_RETRY_TIME
2095
2096  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
2097
2098  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
2099
2100
2101The following environment variables may be used and automatically
2102updated by the network boot commands ("bootp" and "rarpboot"),
2103depending the information provided by your boot server:
2104
2105  bootfile	- see above
2106  dnsip		- IP address of your Domain Name Server
2107  gatewayip	- IP address of the Gateway (Router) to use
2108  hostname	- Target hostname
2109  ipaddr	- see above
2110  netmask	- Subnet Mask
2111  rootpath	- Pathname of the root filesystem on the NFS server
2112  serverip	- see above
2113
2114
2115There are two special Environment Variables:
2116
2117  serial#	- contains hardware identification information such
2118		  as type string and/or serial number
2119  ethaddr	- Ethernet address
2120
2121These variables can be set only once (usually during manufacturing of
2122the board). U-Boot refuses to delete or overwrite these variables
2123once they have been set once.
2124
2125
2126Further special Environment Variables:
2127
2128  ver		- Contains the U-Boot version string as printed
2129		  with the "version" command. This variable is
2130		  readonly (see CONFIG_VERSION_VARIABLE).
2131
2132
2133Please note that changes to some configuration parameters may take
2134only effect after the next boot (yes, that's just like Windoze :-).
2135
2136
2137Command Line Parsing:
2138=====================
2139
2140There are two different command line parsers available  with  U-Boot:
2141the old "simple" one, and the much more pwerful "hush" shell:
2142
2143Old, simple command line parser:
2144--------------------------------
2145
2146- supports environment variables (through setenv / saveenv commands)
2147- several commands on one line, separated by ';'
2148- variable substitution using "... $(name) ..." syntax
2149- special characters ('$', ';') can be escaped by prefixing with '\',
2150  for example:
2151	setenv bootcmd bootm \$(address)
2152- You can also escape text by enclosing in single apostrophes, for example:
2153	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2154
2155Hush shell:
2156-----------
2157
2158- similar to Bourne shell, with control structures like
2159  if...then...else...fi, for...do...done; while...do...done,
2160  until...do...done, ...
2161- supports environment ("global") variables (through setenv / saveenv
2162  commands) and local shell variables (through standard shell syntax
2163  "name=value"); only environment variables can be used with "run"
2164  command
2165
2166General rules:
2167--------------
2168
2169(1) If a command line (or an environment variable executed by a "run"
2170    command) contains several commands separated by semicolon, and
2171    one of these commands fails, then the remaining commands will be
2172    executed anyway.
2173
2174(2) If you execute several variables with one call to run (i. e.
2175    calling run with a list af variables as arguments), any failing
2176    command will cause "run" to terminate, i. e. the remaining
2177    variables are not executed.
2178
2179Note for Redundant Ethernet Interfaces:
2180=======================================
2181
2182Some boards come with redundand ethernet interfaces; U-Boot supports
2183such configurations and is capable of automatic selection of a
2184"working" interface when needed. MAC assignemnt works as follows:
2185
2186Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2187MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2188"eth1addr" (=>eth1), "eth2addr", ...
2189
2190If the network interface stores some valid MAC address (for instance
2191in SROM), this is used as default address if there is NO correspon-
2192ding setting in the environment; if the corresponding environment
2193variable is set, this overrides the settings in the card; that means:
2194
2195o If the SROM has a valid MAC address, and there is no address in the
2196  environment, the SROM's address is used.
2197
2198o If there is no valid address in the SROM, and a definition in the
2199  environment exists, then the value from the environment variable is
2200  used.
2201
2202o If both the SROM and the environment contain a MAC address, and
2203  both addresses are the same, this MAC address is used.
2204
2205o If both the SROM and the environment contain a MAC address, and the
2206  addresses differ, the value from the environment is used and a
2207  warning is printed.
2208
2209o If neither SROM nor the environment contain a MAC address, an error
2210  is raised.
2211
2212
2213Image Formats:
2214==============
2215
2216The "boot" commands of this monitor operate on "image" files which
2217can be basicly anything, preceeded by a special header; see the
2218definitions in include/image.h for details; basicly, the header
2219defines the following image properties:
2220
2221* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2222  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2223  LynxOS, pSOS, QNX, RTEMS, ARTOS;
2224  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
2225* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2226  IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2227  Currently supported: PowerPC).
2228* Compression Type (Provisions for uncompressed, gzip, bzip2;
2229  Currently supported: uncompressed, gzip).
2230* Load Address
2231* Entry Point
2232* Image Name
2233* Image Timestamp
2234
2235The header is marked by a special Magic Number, and both the header
2236and the data portions of the image are secured against corruption by
2237CRC32 checksums.
2238
2239
2240Linux Support:
2241==============
2242
2243Although U-Boot should support any OS or standalone application
2244easily, Linux has always been in the focus during the design of
2245U-Boot.
2246
2247U-Boot includes many features that so far have been part of some
2248special "boot loader" code within the Linux kernel. Also, any
2249"initrd" images to be used are no longer part of one big Linux image;
2250instead, kernel and "initrd" are separate images. This implementation
2251serves serveral purposes:
2252
2253- the same features can be used for other OS or standalone
2254  applications (for instance: using compressed images to reduce the
2255  Flash memory footprint)
2256
2257- it becomes much easier to port new Linux kernel versions because
2258  lots of low-level, hardware dependend stuff are done by U-Boot
2259
2260- the same Linux kernel image can now be used with different "initrd"
2261  images; of course this also means that different kernel images can
2262  be run with the same "initrd". This makes testing easier (you don't
2263  have to build a new "zImage.initrd" Linux image when you just
2264  change a file in your "initrd"). Also, a field-upgrade of the
2265  software is easier now.
2266
2267
2268Linux HOWTO:
2269============
2270
2271Porting Linux to U-Boot based systems:
2272---------------------------------------
2273
2274U-Boot cannot save you from doing all the necessary modifications to
2275configure the Linux device drivers for use with your target hardware
2276(no, we don't intend to provide a full virtual machine interface to
2277Linux :-).
2278
2279But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2280
2281Just make sure your machine specific header file (for instance
2282include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2283Information structure as we define in include/u-boot.h, and make
2284sure that your definition of IMAP_ADDR uses the same value as your
2285U-Boot configuration in CFG_IMMR.
2286
2287
2288Configuring the Linux kernel:
2289-----------------------------
2290
2291No specific requirements for U-Boot. Make sure you have some root
2292device (initial ramdisk, NFS) for your target system.
2293
2294
2295Building a Linux Image:
2296-----------------------
2297
2298With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2299not used. If you use recent kernel source, a new build target
2300"uImage" will exist which automatically builds an image usable by
2301U-Boot. Most older kernels also have support for a "pImage" target,
2302which was introduced for our predecessor project PPCBoot and uses a
2303100% compatible format.
2304
2305Example:
2306
2307	make TQM850L_config
2308	make oldconfig
2309	make dep
2310	make uImage
2311
2312The "uImage" build target uses a special tool (in 'tools/mkimage') to
2313encapsulate a compressed Linux kernel image with header  information,
2314CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2315
2316* build a standard "vmlinux" kernel image (in ELF binary format):
2317
2318* convert the kernel into a raw binary image:
2319
2320	${CROSS_COMPILE}-objcopy -O binary \
2321				 -R .note -R .comment \
2322				 -S vmlinux linux.bin
2323
2324* compress the binary image:
2325
2326	gzip -9 linux.bin
2327
2328* package compressed binary image for U-Boot:
2329
2330	mkimage -A ppc -O linux -T kernel -C gzip \
2331		-a 0 -e 0 -n "Linux Kernel Image" \
2332		-d linux.bin.gz uImage
2333
2334
2335The "mkimage" tool can also be used to create ramdisk images for use
2336with U-Boot, either separated from the Linux kernel image, or
2337combined into one file. "mkimage" encapsulates the images with a 64
2338byte header containing information about target architecture,
2339operating system, image type, compression method, entry points, time
2340stamp, CRC32 checksums, etc.
2341
2342"mkimage" can be called in two ways: to verify existing images and
2343print the header information, or to build new images.
2344
2345In the first form (with "-l" option) mkimage lists the information
2346contained in the header of an existing U-Boot image; this includes
2347checksum verification:
2348
2349	tools/mkimage -l image
2350	  -l ==> list image header information
2351
2352The second form (with "-d" option) is used to build a U-Boot image
2353from a "data file" which is used as image payload:
2354
2355	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2356		      -n name -d data_file image
2357	  -A ==> set architecture to 'arch'
2358	  -O ==> set operating system to 'os'
2359	  -T ==> set image type to 'type'
2360	  -C ==> set compression type 'comp'
2361	  -a ==> set load address to 'addr' (hex)
2362	  -e ==> set entry point to 'ep' (hex)
2363	  -n ==> set image name to 'name'
2364	  -d ==> use image data from 'datafile'
2365
2366Right now, all Linux kernels use the same load address	(0x00000000),
2367but the entry point address depends on the kernel version:
2368
2369- 2.2.x kernels have the entry point at 0x0000000C,
2370- 2.3.x and later kernels have the entry point at 0x00000000.
2371
2372So a typical call to build a U-Boot image would read:
2373
2374	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2375	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2376	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2377	> examples/uImage.TQM850L
2378	Image Name:   2.4.4 kernel for TQM850L
2379	Created:      Wed Jul 19 02:34:59 2000
2380	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
2381	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
2382	Load Address: 0x00000000
2383	Entry Point:  0x00000000
2384
2385To verify the contents of the image (or check for corruption):
2386
2387	-> tools/mkimage -l examples/uImage.TQM850L
2388	Image Name:   2.4.4 kernel for TQM850L
2389	Created:      Wed Jul 19 02:34:59 2000
2390	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
2391	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
2392	Load Address: 0x00000000
2393	Entry Point:  0x00000000
2394
2395NOTE: for embedded systems where boot time is critical you can trade
2396speed for memory and install an UNCOMPRESSED image instead: this
2397needs more space in Flash, but boots much faster since it does not
2398need to be uncompressed:
2399
2400	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2401	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2402	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2403	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2404	> examples/uImage.TQM850L-uncompressed
2405	Image Name:   2.4.4 kernel for TQM850L
2406	Created:      Wed Jul 19 02:34:59 2000
2407	Image Type:   PowerPC Linux Kernel Image (uncompressed)
2408	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
2409	Load Address: 0x00000000
2410	Entry Point:  0x00000000
2411
2412
2413Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2414when your kernel is intended to use an initial ramdisk:
2415
2416	-> tools/mkimage -n 'Simple Ramdisk Image' \
2417	> -A ppc -O linux -T ramdisk -C gzip \
2418	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2419	Image Name:   Simple Ramdisk Image
2420	Created:      Wed Jan 12 14:01:50 2000
2421	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
2422	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
2423	Load Address: 0x00000000
2424	Entry Point:  0x00000000
2425
2426
2427Installing a Linux Image:
2428-------------------------
2429
2430To downloading a U-Boot image over the serial (console) interface,
2431you must convert the image to S-Record format:
2432
2433	objcopy -I binary -O srec examples/image examples/image.srec
2434
2435The 'objcopy' does not understand the information in the U-Boot
2436image header, so the resulting S-Record file will be relative to
2437address 0x00000000. To load it to a given address, you need to
2438specify the target address as 'offset' parameter with the 'loads'
2439command.
2440
2441Example: install the image to address 0x40100000 (which on the
2442TQM8xxL is in the first Flash bank):
2443
2444	=> erase 40100000 401FFFFF
2445
2446	.......... done
2447	Erased 8 sectors
2448
2449	=> loads 40100000
2450	## Ready for S-Record download ...
2451	~>examples/image.srec
2452	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2453	...
2454	15989 15990 15991 15992
2455	[file transfer complete]
2456	[connected]
2457	## Start Addr = 0x00000000
2458
2459
2460You can check the success of the download using the 'iminfo' command;
2461this includes a checksum verification so you  can  be  sure  no	 data
2462corruption happened:
2463
2464	=> imi 40100000
2465
2466	## Checking Image at 40100000 ...
2467	   Image Name:	 2.2.13 for initrd on TQM850L
2468	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2469	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2470	   Load Address: 00000000
2471	   Entry Point:	 0000000c
2472	   Verifying Checksum ... OK
2473
2474
2475Boot Linux:
2476-----------
2477
2478The "bootm" command is used to boot an application that is stored in
2479memory (RAM or Flash). In case of a Linux kernel image, the contents
2480of the "bootargs" environment variable is passed to the kernel as
2481parameters. You can check and modify this variable using the
2482"printenv" and "setenv" commands:
2483
2484
2485	=> printenv bootargs
2486	bootargs=root=/dev/ram
2487
2488	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2489
2490	=> printenv bootargs
2491	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2492
2493	=> bootm 40020000
2494	## Booting Linux kernel at 40020000 ...
2495	   Image Name:	 2.2.13 for NFS on TQM850L
2496	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2497	   Data Size:	 381681 Bytes = 372 kB = 0 MB
2498	   Load Address: 00000000
2499	   Entry Point:	 0000000c
2500	   Verifying Checksum ... OK
2501	   Uncompressing Kernel Image ... OK
2502	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
2503	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2504	time_init: decrementer frequency = 187500000/60
2505	Calibrating delay loop... 49.77 BogoMIPS
2506	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2507	...
2508
2509If you want to boot a Linux kernel with initial ram disk, you pass
2510the memory addreses of both the kernel and the initrd image (PPBCOOT
2511format!) to the "bootm" command:
2512
2513	=> imi 40100000 40200000
2514
2515	## Checking Image at 40100000 ...
2516	   Image Name:	 2.2.13 for initrd on TQM850L
2517	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2518	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2519	   Load Address: 00000000
2520	   Entry Point:	 0000000c
2521	   Verifying Checksum ... OK
2522
2523	## Checking Image at 40200000 ...
2524	   Image Name:	 Simple Ramdisk Image
2525	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
2526	   Data Size:	 566530 Bytes = 553 kB = 0 MB
2527	   Load Address: 00000000
2528	   Entry Point:	 00000000
2529	   Verifying Checksum ... OK
2530
2531	=> bootm 40100000 40200000
2532	## Booting Linux kernel at 40100000 ...
2533	   Image Name:	 2.2.13 for initrd on TQM850L
2534	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2535	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2536	   Load Address: 00000000
2537	   Entry Point:	 0000000c
2538	   Verifying Checksum ... OK
2539	   Uncompressing Kernel Image ... OK
2540	## Loading RAMDisk Image at 40200000 ...
2541	   Image Name:	 Simple Ramdisk Image
2542	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
2543	   Data Size:	 566530 Bytes = 553 kB = 0 MB
2544	   Load Address: 00000000
2545	   Entry Point:	 00000000
2546	   Verifying Checksum ... OK
2547	   Loading Ramdisk ... OK
2548	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
2549	Boot arguments: root=/dev/ram
2550	time_init: decrementer frequency = 187500000/60
2551	Calibrating delay loop... 49.77 BogoMIPS
2552	...
2553	RAMDISK: Compressed image found at block 0
2554	VFS: Mounted root (ext2 filesystem).
2555
2556	bash#
2557
2558More About U-Boot Image Types:
2559------------------------------
2560
2561U-Boot supports the following image types:
2562
2563   "Standalone Programs" are directly runnable in the environment
2564	provided by U-Boot; it is expected that (if they behave
2565	well) you can continue to work in U-Boot after return from
2566	the Standalone Program.
2567   "OS Kernel Images" are usually images of some Embedded OS which
2568	will take over control completely. Usually these programs
2569	will install their own set of exception handlers, device
2570	drivers, set up the MMU, etc. - this means, that you cannot
2571	expect to re-enter U-Boot except by resetting the CPU.
2572   "RAMDisk Images" are more or less just data blocks, and their
2573	parameters (address, size) are passed to an OS kernel that is
2574	being started.
2575   "Multi-File Images" contain several images, typically an OS
2576	(Linux) kernel image and one or more data images like
2577	RAMDisks. This construct is useful for instance when you want
2578	to boot over the network using BOOTP etc., where the boot
2579	server provides just a single image file, but you want to get
2580	for instance an OS kernel and a RAMDisk image.
2581
2582	"Multi-File Images" start with a list of image sizes, each
2583	image size (in bytes) specified by an "uint32_t" in network
2584	byte order. This list is terminated by an "(uint32_t)0".
2585	Immediately after the terminating 0 follow the images, one by
2586	one, all aligned on "uint32_t" boundaries (size rounded up to
2587	a multiple of 4 bytes).
2588
2589   "Firmware Images" are binary images containing firmware (like
2590	U-Boot or FPGA images) which usually will be programmed to
2591	flash memory.
2592
2593   "Script files" are command sequences that will be executed by
2594	U-Boot's command interpreter; this feature is especially
2595	useful when you configure U-Boot to use a real shell (hush)
2596	as command interpreter.
2597
2598
2599Standalone HOWTO:
2600=================
2601
2602One of the features of U-Boot is that you can dynamically load and
2603run "standalone" applications, which can use some resources of
2604U-Boot like console I/O functions or interrupt services.
2605
2606Two simple examples are included with the sources:
2607
2608"Hello World" Demo:
2609-------------------
2610
2611'examples/hello_world.c' contains a small "Hello World" Demo
2612application; it is automatically compiled when you build U-Boot.
2613It's configured to run at address 0x00040004, so you can play with it
2614like that:
2615
2616	=> loads
2617	## Ready for S-Record download ...
2618	~>examples/hello_world.srec
2619	1 2 3 4 5 6 7 8 9 10 11 ...
2620	[file transfer complete]
2621	[connected]
2622	## Start Addr = 0x00040004
2623
2624	=> go 40004 Hello World! This is a test.
2625	## Starting application at 0x00040004 ...
2626	Hello World
2627	argc = 7
2628	argv[0] = "40004"
2629	argv[1] = "Hello"
2630	argv[2] = "World!"
2631	argv[3] = "This"
2632	argv[4] = "is"
2633	argv[5] = "a"
2634	argv[6] = "test."
2635	argv[7] = "<NULL>"
2636	Hit any key to exit ...
2637
2638	## Application terminated, rc = 0x0
2639
2640Another example, which demonstrates how to register a CPM interrupt
2641handler with the U-Boot code, can be found in 'examples/timer.c'.
2642Here, a CPM timer is set up to generate an interrupt every second.
2643The interrupt service routine is trivial, just printing a '.'
2644character, but this is just a demo program. The application can be
2645controlled by the following keys:
2646
2647	? - print current values og the CPM Timer registers
2648	b - enable interrupts and start timer
2649	e - stop timer and disable interrupts
2650	q - quit application
2651
2652	=> loads
2653	## Ready for S-Record download ...
2654	~>examples/timer.srec
2655	1 2 3 4 5 6 7 8 9 10 11 ...
2656	[file transfer complete]
2657	[connected]
2658	## Start Addr = 0x00040004
2659
2660	=> go 40004
2661	## Starting application at 0x00040004 ...
2662	TIMERS=0xfff00980
2663	Using timer 1
2664	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2665
2666Hit 'b':
2667	[q, b, e, ?] Set interval 1000000 us
2668	Enabling timer
2669Hit '?':
2670	[q, b, e, ?] ........
2671	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2672Hit '?':
2673	[q, b, e, ?] .
2674	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2675Hit '?':
2676	[q, b, e, ?] .
2677	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2678Hit '?':
2679	[q, b, e, ?] .
2680	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2681Hit 'e':
2682	[q, b, e, ?] ...Stopping timer
2683Hit 'q':
2684	[q, b, e, ?] ## Application terminated, rc = 0x0
2685
2686
2687Minicom warning:
2688================
2689
2690Over time, many people have reported problems when trying to used the
2691"minicom" terminal emulation program for serial download. I (wd)
2692consider minicom to be broken, and recommend not to use it. Under
2693Unix, I recommend to use C-Kermit for general purpose use (and
2694especially for kermit binary protocol download ("loadb" command), and
2695use "cu" for S-Record download ("loads" command).
2696
2697Nevertheless, if you absolutely want to use it try adding this
2698configuration to your "File transfer protocols" section:
2699
2700	   Name    Program                      Name U/D FullScr IO-Red. Multi
2701	X  kermit  /usr/bin/kermit -i -l %l -s   Y    U    Y       N      N
2702	Y  kermit  /usr/bin/kermit -i -l %l -r   N    D    Y       N      N
2703
2704
2705NetBSD Notes:
2706=============
2707
2708Starting at version 0.9.2, U-Boot supports NetBSD both as host
2709(build U-Boot) and target system (boots NetBSD/mpc8xx).
2710
2711Building requires a cross environment; it is known to work on
2712NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2713need gmake since the Makefiles are not compatible with BSD make).
2714Note that the cross-powerpc package does not install include files;
2715attempting to build U-Boot will fail because <machine/ansi.h> is
2716missing.  This file has to be installed and patched manually:
2717
2718	# cd /usr/pkg/cross/powerpc-netbsd/include
2719	# mkdir powerpc
2720	# ln -s powerpc machine
2721	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2722	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
2723
2724Native builds *don't* work due to incompatibilities between native
2725and U-Boot include files.
2726
2727Booting assumes that (the first part of) the image booted is a
2728stage-2 loader which in turn loads and then invokes the kernel
2729proper. Loader sources will eventually appear in the NetBSD source
2730tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2731meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2732details.
2733
2734
2735Implementation Internals:
2736=========================
2737
2738The following is not intended to be a complete description of every
2739implementation detail. However, it should help to understand the
2740inner workings of U-Boot and make it easier to port it to custom
2741hardware.
2742
2743
2744Initial Stack, Global Data:
2745---------------------------
2746
2747The implementation of U-Boot is complicated by the fact that U-Boot
2748starts running out of ROM (flash memory), usually without access to
2749system RAM (because the memory controller is not initialized yet).
2750This means that we don't have writable Data or BSS segments, and BSS
2751is not initialized as zero. To be able to get a C environment working
2752at all, we have to allocate at least a minimal stack. Implementation
2753options for this are defined and restricted by the CPU used: Some CPU
2754models provide on-chip memory (like the IMMR area on MPC8xx and
2755MPC826x processors), on others (parts of) the data cache can be
2756locked as (mis-) used as memory, etc.
2757
2758	Chris Hallinan posted a good summy of  these  issues  to  the
2759	u-boot-users mailing list:
2760
2761	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2762	From: "Chris Hallinan" <clh@net1plus.com>
2763	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2764	...
2765
2766	Correct me if I'm wrong, folks, but the way I understand it
2767	is this: Using DCACHE as initial RAM for Stack, etc, does not
2768	require any physical RAM backing up the cache. The cleverness
2769	is that the cache is being used as a temporary supply of
2770	necessary storage before the SDRAM controller is setup. It's
2771	beyond the scope of this list to expain the details, but you
2772	can see how this works by studying the cache architecture and
2773	operation in the architecture and processor-specific manuals.
2774
2775	OCM is On Chip Memory, which I believe the 405GP has 4K. It
2776	is another option for the system designer to use as an
2777	initial stack/ram area prior to SDRAM being available. Either
2778	option should work for you. Using CS 4 should be fine if your
2779	board designers haven't used it for something that would
2780	cause you grief during the initial boot! It is frequently not
2781	used.
2782
2783	CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2784	with your processor/board/system design. The default value
2785	you will find in any recent u-boot distribution in
2786	Walnut405.h should work for you. I'd set it to a value larger
2787	than your SDRAM module. If you have a 64MB SDRAM module, set
2788	it above 400_0000. Just make sure your board has no resources
2789	that are supposed to respond to that address! That code in
2790	start.S has been around a while and should work as is when
2791	you get the config right.
2792
2793	-Chris Hallinan
2794	DS4.COM, Inc.
2795
2796It is essential to remember this, since it has some impact on the C
2797code for the initialization procedures:
2798
2799* Initialized global data (data segment) is read-only. Do not attempt
2800  to write it.
2801
2802* Do not use any unitialized global data (or implicitely initialized
2803  as zero data - BSS segment) at all - this is undefined, initiali-
2804  zation is performed later (when relocationg to RAM).
2805
2806* Stack space is very limited. Avoid big data buffers or things  like
2807  that.
2808
2809Having only the stack as writable memory limits means we cannot use
2810normal global data to share information beween the code. But it
2811turned out that the implementation of U-Boot can be greatly
2812simplified by making a global data structure (gd_t) available to all
2813functions. We could pass a pointer to this data as argument to _all_
2814functions, but this would bloat the code. Instead we use a feature of
2815the GCC compiler (Global Register Variables) to share the data: we
2816place a pointer (gd) to the global data into a register which we
2817reserve for this purpose.
2818
2819When chosing a register for such a purpose we are restricted  by  the
2820relevant  (E)ABI  specifications for the current architecture, and by
2821GCC's implementation.
2822
2823For PowerPC, the following registers have specific use:
2824	R1:	stack pointer
2825	R2:	TOC pointer
2826	R3-R4:	parameter passing and return values
2827	R5-R10:	parameter passing
2828	R13:	small data area pointer
2829	R30:	GOT pointer
2830	R31:	frame pointer
2831
2832	(U-Boot also uses R14 as internal GOT pointer.)
2833
2834    ==> U-Boot will use R29 to hold a pointer to the global data
2835
2836    Note: on PPC, we could use a static initializer (since the
2837    address of the global data structure is known at compile time),
2838    but it turned out that reserving a register results in somewhat
2839    smaller code - although the code savings are not that big (on
2840    average for all boards 752 bytes for the whole U-Boot image,
2841    624 text + 127 data).
2842
2843On ARM, the following registers are used:
2844
2845	R0:	function argument word/integer result
2846	R1-R3:	function argument word
2847	R9:	GOT pointer
2848	R10:	stack limit (used only if stack checking if enabled)
2849	R11:	argument (frame) pointer
2850	R12:	temporary workspace
2851	R13:	stack pointer
2852	R14:	link register
2853	R15:	program counter
2854
2855    ==> U-Boot will use R8 to hold a pointer to the global data
2856
2857
2858Memory Management:
2859------------------
2860
2861U-Boot runs in system state and uses physical addresses, i.e. the
2862MMU is not used either for address mapping nor for memory protection.
2863
2864The available memory is mapped to fixed addresses using the memory
2865controller. In this process, a contiguous block is formed for each
2866memory type (Flash, SDRAM, SRAM), even when it consists of several
2867physical memory banks.
2868
2869U-Boot is installed in the first 128 kB of the first Flash bank (on
2870TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2871booting and sizing and initializing DRAM, the code relocates itself
2872to the upper end of DRAM. Immediately below the U-Boot code some
2873memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2874configuration setting]. Below that, a structure with global Board
2875Info data is placed, followed by the stack (growing downward).
2876
2877Additionally, some exception handler code is copied to the low 8 kB
2878of DRAM (0x00000000 ... 0x00001FFF).
2879
2880So a typical memory configuration with 16 MB of DRAM could look like
2881this:
2882
2883	0x0000 0000	Exception Vector code
2884	      :
2885	0x0000 1FFF
2886	0x0000 2000	Free for Application Use
2887	      :
2888	      :
2889
2890	      :
2891	      :
2892	0x00FB FF20	Monitor Stack (Growing downward)
2893	0x00FB FFAC	Board Info Data and permanent copy of global data
2894	0x00FC 0000	Malloc Arena
2895	      :
2896	0x00FD FFFF
2897	0x00FE 0000	RAM Copy of Monitor Code
2898	...		eventually: LCD or video framebuffer
2899	...		eventually: pRAM (Protected RAM - unchanged by reset)
2900	0x00FF FFFF	[End of RAM]
2901
2902
2903System Initialization:
2904----------------------
2905
2906In the reset configuration, U-Boot starts at the reset entry point
2907(on most PowerPC systens at address 0x00000100). Because of the reset
2908configuration for CS0# this is a mirror of the onboard Flash memory.
2909To be able to re-map memory U-Boot then jumps to it's link address.
2910To be able to implement the initialization code in C, a (small!)
2911initial stack is set up in the internal Dual Ported RAM (in case CPUs
2912which provide such a feature like MPC8xx or MPC8260), or in a locked
2913part of the data cache. After that, U-Boot initializes the CPU core,
2914the caches and the SIU.
2915
2916Next, all (potentially) available memory banks are mapped using a
2917preliminary mapping. For example, we put them on 512 MB boundaries
2918(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2919on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2920programmed for SDRAM access. Using the temporary configuration, a
2921simple memory test is run that determines the size of the SDRAM
2922banks.
2923
2924When there is more than one SDRAM bank, and the banks are of
2925different size, the larger is mapped first. For equal size, the first
2926bank (CS2#) is mapped first. The first mapping is always for address
29270x00000000, with any additional banks following immediately to create
2928contiguous memory starting from 0.
2929
2930Then, the monitor installs itself at the upper end of the SDRAM area
2931and allocates memory for use by malloc() and for the global Board
2932Info data; also, the exception vector code is copied to the low RAM
2933pages, and the final stack is set up.
2934
2935Only after this relocation will you have a "normal" C environment;
2936until that you are restricted in several ways, mostly because you are
2937running from ROM, and because the code will have to be relocated to a
2938new address in RAM.
2939
2940
2941U-Boot Porting Guide:
2942----------------------
2943
2944[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2945list, October 2002]
2946
2947
2948int main (int argc, char *argv[])
2949{
2950	sighandler_t no_more_time;
2951
2952	signal (SIGALRM, no_more_time);
2953	alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2954
2955	if (available_money > available_manpower) {
2956		pay consultant to port U-Boot;
2957		return 0;
2958	}
2959
2960	Download latest U-Boot source;
2961
2962	Subscribe to u-boot-users mailing list;
2963
2964	if (clueless) {
2965		email ("Hi, I am new to U-Boot, how do I get started?");
2966	}
2967
2968	while (learning) {
2969		Read the README file in the top level directory;
2970		Read http://www.denx.de/re/DPLG.html
2971		Read the source, Luke;
2972	}
2973
2974	if (available_money > toLocalCurrency ($2500)) {
2975		Buy a BDI2000;
2976	} else {
2977		Add a lot of aggravation and time;
2978	}
2979
2980	Create your own board support subdirectory;
2981
2982	Create your own board config file;
2983
2984	while (!running) {
2985		do {
2986			Add / modify source code;
2987		} until (compiles);
2988		Debug;
2989		if (clueless)
2990			email ("Hi, I am having problems...");
2991	}
2992	Send patch file to Wolfgang;
2993
2994	return 0;
2995}
2996
2997void no_more_time (int sig)
2998{
2999      hire_a_guru();
3000}
3001
3002
3003Coding Standards:
3004-----------------
3005
3006All contributions to U-Boot should conform to the Linux kernel
3007coding style; see the file "Documentation/CodingStyle" in your Linux
3008kernel source directory.
3009
3010Please note that U-Boot is implemented in C (and to some small parts
3011in Assembler); no C++ is used, so please do not use C++ style
3012comments (//) in your code.
3013
3014Submissions which do not conform to the standards may be returned
3015with a request to reformat the changes.
3016
3017
3018Submitting Patches:
3019-------------------
3020
3021Since the number of patches for U-Boot is growing, we need to
3022establish some rules. Submissions which do not conform to these rules
3023may be rejected, even when they contain important and valuable stuff.
3024
3025
3026When you send a patch, please include the following information with
3027it:
3028
3029* For bug fixes: a description of the bug and how your patch fixes
3030  this bug. Please try to include a way of demonstrating that the
3031  patch actually fixes something.
3032
3033* For new features: a description of the feature and your
3034  implementation.
3035
3036* A CHANGELOG entry as plaintext (separate from the patch)
3037
3038* For major contributions, your entry to the CREDITS file
3039
3040* When you add support for a new board, don't forget to add this
3041  board to the MAKEALL script, too.
3042
3043* If your patch adds new configuration options, don't forget to
3044  document these in the README file.
3045
3046* The patch itself. If you are accessing the CVS repository use "cvs
3047  update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3048  version of diff does not support these options, then get the latest
3049  version of GNU diff.
3050
3051  We accept patches as plain text, MIME attachments or as uuencoded
3052  gzipped text.
3053
3054* If one logical set of modifications affects or creates several
3055  files, all these changes shall be submitted in a SINGLE patch file.
3056
3057* Changesets that contain different, unrelated modifications shall be
3058  submitted as SEPARATE patches, one patch per changeset.
3059
3060
3061Notes:
3062
3063* Before sending the patch, run the MAKEALL script on your patched
3064  source tree and make sure that no errors or warnings are reported
3065  for any of the boards.
3066
3067* Keep your modifications to the necessary minimum: A patch
3068  containing several unrelated changes or arbitrary reformats will be
3069  returned with a request to re-formatting / split it.
3070
3071* If you modify existing code, make sure that your new code does not
3072  add to the memory footprint of the code ;-) Small is beautiful!
3073  When adding new features, these should compile conditionally only
3074  (using #ifdef), and the resulting code with the new feature
3075  disabled must not need more memory than the old code without your
3076  modification.
3077