xref: /rk3399_rockchip-uboot/README (revision fc3e2165efda62670d447617a7d44c5666178ea4)
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 dependent files
123- common	Misc architecture independent functions
124- cpu		CPU specific files
125- disk		Code for disk drive partition handling
126- doc		Documentation (don't expect too much)
127- drivers	Commonly 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/arm925t	Files specific to ARM	   925	   CPUs
144- cpu/arm926ejs	Files specific to ARM	926	CPUs
145- cpu/mpc5xx	Files specific to Motorola MPC5xx  CPUs
146- cpu/mpc8xx	Files specific to Motorola MPC8xx  CPUs
147- cpu/mpc824x	Files specific to Motorola MPC824x CPUs
148- cpu/mpc8260	Files specific to Motorola MPC8260 CPU
149- cpu/ppc4xx	Files specific to IBM	   4xx	   CPUs
150
151
152- board/LEOX/   Files specific to boards manufactured by The LEOX team
153- board/LEOX/elpt860	Files specific to ELPT860 boards
154- board/RPXClassic
155		Files specific to RPXClassic boards
156- board/RPXlite	Files specific to RPXlite    boards
157- board/at91rm9200dk Files specific to AT91RM9200DK boards
158- board/c2mon	Files specific to c2mon	     boards
159- board/cmi	Files specific to cmi        boards
160- board/cogent	Files specific to Cogent     boards
161		(need further configuration)
162		Files specific to CPCIISER4  boards
163- board/cpu86	Files specific to CPU86      boards
164- board/cray/	Files specific to boards manufactured by Cray
165- board/cray/L1		Files specific to L1         boards
166- board/cu824	Files specific to CU824	     boards
167- board/ebony   Files specific to IBM Ebony board
168- board/eric	Files specific to ERIC	     boards
169- board/esd/	Files specific to boards manufactured by ESD
170- board/esd/adciop	Files specific to ADCIOP     boards
171- board/esd/ar405	Files specific to AR405	     boards
172- board/esd/canbt	Files specific to CANBT	     boards
173- board/esd/cpci405	Files specific to CPCI405    boards
174- board/esd/cpciiser4	Files specific to CPCIISER4  boards
175- board/esd/common	Common files for ESD boards
176- board/esd/dasa_sim	Files specific to DASA_SIM   boards
177- board/esd/du405	Files specific to DU405      boards
178- board/esd/ocrtc	Files specific to OCRTC      boards
179- board/esd/pci405	Files specific to PCI405     boards
180- board/esteem192e
181		Files specific to ESTEEM192E boards
182- board/etx094	Files specific to ETX_094    boards
183- board/evb64260
184		Files specific to EVB64260   boards
185- board/fads	Files specific to FADS	     boards
186- board/flagadm Files specific to FLAGADM    boards
187- board/gen860t Files specific to GEN860T and GEN860T_SC    boards
188- board/genietv Files specific to GENIETV    boards
189- board/gth	Files specific to GTH	     boards
190- board/hermes	Files specific to HERMES     boards
191- board/hymod	Files specific to HYMOD	     boards
192- board/icu862	Files specific to ICU862     boards
193- board/ip860	Files specific to IP860	     boards
194- board/iphase4539
195		Files specific to Interphase4539 boards
196- board/ivm	Files specific to IVMS8/IVML24 boards
197- board/lantec	Files specific to LANTEC     boards
198- board/lwmon	Files specific to LWMON	     boards
199- board/mbx8xx	Files specific to MBX	     boards
200- board/mpc8260ads
201		Files specific to MPC8260ADS and PQ2FADS-ZU boards
202- board/mpl/	Files specific to boards manufactured by MPL
203- board/mpl/common	Common files for MPL boards
204- board/mpl/pip405	Files specific to PIP405     boards
205- board/mpl/mip405	Files specific to MIP405     boards
206- board/mpl/vcma9	Files specific to VCMA9      boards
207- board/musenki	Files specific to MUSEKNI    boards
208- board/mvs1	Files specific to MVS1       boards
209- board/nx823   Files specific to NX823      boards
210- board/oxc	Files specific to OXC        boards
211- board/omap1510inn
212		Files specific to OMAP 1510 Innovator boards
213- board/omap1610inn
214		Files specific to OMAP 1610 Innovator boards
215- board/pcippc2	Files specific to PCIPPC2/PCIPPC6 boards
216- board/pm826	Files specific to PM826      boards
217- board/ppmc8260
218		Files specific to PPMC8260   boards
219- board/rpxsuper
220		Files specific to RPXsuper   boards
221- board/rsdproto
222		Files specific to RSDproto   boards
223- board/sandpoint
224		Files specific to Sandpoint  boards
225- board/sbc8260	Files specific to SBC8260    boards
226- board/sacsng	Files specific to SACSng     boards
227- board/siemens Files specific to boards manufactured by Siemens AG
228- board/siemens/CCM	Files specific to CCM	     boards
229- board/siemens/IAD210	Files specific to IAD210     boards
230- board/siemens/SCM	Files specific to SCM        boards
231- board/siemens/pcu_e	Files specific to PCU_E	     boards
232- board/sixnet	Files specific to SIXNET     boards
233- board/spd8xx	Files specific to SPD8xxTS   boards
234- board/tqm8260 Files specific to TQM8260    boards
235- board/tqm8xx	Files specific to TQM8xxL    boards
236- board/w7o	Files specific to W7O        boards
237- board/walnut405
238		Files specific to Walnut405  boards
239- board/westel/	Files specific to boards manufactured by Westel Wireless
240- board/westel/amx860	Files specific to AMX860     boards
241- board/utx8245	Files specific to UTX8245   boards
242
243Software Configuration:
244=======================
245
246Configuration is usually done using C preprocessor defines; the
247rationale behind that is to avoid dead code whenever possible.
248
249There are two classes of configuration variables:
250
251* Configuration _OPTIONS_:
252  These are selectable by the user and have names beginning with
253  "CONFIG_".
254
255* Configuration _SETTINGS_:
256  These depend on the hardware etc. and should not be meddled with if
257  you don't know what you're doing; they have names beginning with
258  "CFG_".
259
260Later we will add a configuration tool - probably similar to or even
261identical to what's used for the Linux kernel. Right now, we have to
262do the configuration by hand, which means creating some symbolic
263links and editing some configuration files. We use the TQM8xxL boards
264as an example here.
265
266
267Selection of Processor Architecture and Board Type:
268---------------------------------------------------
269
270For all supported boards there are ready-to-use default
271configurations available; just type "make <board_name>_config".
272
273Example: For a TQM823L module type:
274
275	cd u-boot
276	make TQM823L_config
277
278For the Cogent platform, you need to specify the cpu type as well;
279e.g. "make cogent_mpc8xx_config". And also configure the cogent
280directory according to the instructions in cogent/README.
281
282
283Configuration Options:
284----------------------
285
286Configuration depends on the combination of board and CPU type; all
287such information is kept in a configuration file
288"include/configs/<board_name>.h".
289
290Example: For a TQM823L module, all configuration settings are in
291"include/configs/TQM823L.h".
292
293
294Many of the options are named exactly as the corresponding Linux
295kernel configuration options. The intention is to make it easier to
296build a config tool - later.
297
298
299The following options need to be configured:
300
301- CPU Type:	Define exactly one of
302
303		PowerPC based CPUs:
304		-------------------
305		CONFIG_MPC823,	CONFIG_MPC850,	CONFIG_MPC855,	CONFIG_MPC860
306	or	CONFIG_MPC5xx
307	or	CONFIG_MPC824X, CONFIG_MPC8260
308	or	CONFIG_IOP480
309	or	CONFIG_405GP
310	or	CONFIG_405EP
311	or	CONFIG_440
312	or	CONFIG_MPC74xx
313	or	CONFIG_750FX
314
315		ARM based CPUs:
316		---------------
317		CONFIG_SA1110
318		CONFIG_ARM7
319		CONFIG_PXA250
320
321
322- Board Type:	Define exactly one of
323
324		PowerPC based boards:
325		---------------------
326
327		CONFIG_ADCIOP,     CONFIG_ICU862      CONFIG_RPXsuper,
328		CONFIG_ADS860,     CONFIG_IP860,      CONFIG_SM850,
329		CONFIG_AMX860,     CONFIG_IPHASE4539, CONFIG_SPD823TS,
330		CONFIG_AR405,      CONFIG_IVML24,     CONFIG_SXNI855T,
331		CONFIG_BAB7xx,     CONFIG_IVML24_128, CONFIG_Sandpoint8240,
332		CONFIG_CANBT,      CONFIG_IVML24_256, CONFIG_Sandpoint8245,
333		CONFIG_CCM,        CONFIG_IVMS8,      CONFIG_TQM823L,
334		CONFIG_CPCI405,    CONFIG_IVMS8_128,  CONFIG_TQM850L,
335		CONFIG_CPCI4052,   CONFIG_IVMS8_256,  CONFIG_TQM855L,
336		CONFIG_CPCIISER4,  CONFIG_LANTEC,     CONFIG_TQM860L,
337		CONFIG_CPU86,      CONFIG_MBX,        CONFIG_TQM8260,
338		CONFIG_CRAYL1,     CONFIG_MBX860T,    CONFIG_TTTech,
339		CONFIG_CU824,      CONFIG_MHPC,       CONFIG_UTX8245,
340		CONFIG_DASA_SIM,   CONFIG_MIP405,     CONFIG_W7OLMC,
341		CONFIG_DU405,      CONFIG_MOUSSE,     CONFIG_W7OLMG,
342		CONFIG_ELPPC,      CONFIG_MPC8260ADS, CONFIG_WALNUT405,
343		CONFIG_ERIC,       CONFIG_MUSENKI,    CONFIG_ZUMA,
344		CONFIG_ESTEEM192E, CONFIG_MVS1,       CONFIG_c2mon,
345		CONFIG_ETX094,     CONFIG_NX823,      CONFIG_cogent_mpc8260,
346		CONFIG_EVB64260,   CONFIG_OCRTC,      CONFIG_cogent_mpc8xx,
347		CONFIG_FADS823,    CONFIG_ORSG,       CONFIG_ep8260,
348		CONFIG_FADS850SAR, CONFIG_OXC,        CONFIG_gw8260,
349		CONFIG_FADS860T,   CONFIG_PCI405,     CONFIG_hermes,
350		CONFIG_FLAGADM,    CONFIG_PCIPPC2,    CONFIG_hymod,
351		CONFIG_FPS850L,    CONFIG_PCIPPC6,    CONFIG_lwmon,
352		CONFIG_GEN860T,    CONFIG_PIP405,     CONFIG_pcu_e,
353		CONFIG_GENIETV,    CONFIG_PM826,      CONFIG_ppmc8260,
354		CONFIG_GTH,        CONFIG_RPXClassic, CONFIG_rsdproto,
355		CONFIG_IAD210,     CONFIG_RPXlite,    CONFIG_sbc8260,
356		CONFIG_EBONY,      CONFIG_sacsng,     CONFIG_FPS860L,
357		CONFIG_V37,        CONFIG_ELPT860,    CONFIG_CMI,
358		CONFIG_NETVIA,     CONFIG_RBC823
359
360		ARM based boards:
361		-----------------
362
363		CONFIG_HHP_CRADLE,  CONFIG_DNP1110,    CONFIG_EP7312,
364		CONFIG_IMPA7,       CONFIG_LART,       CONFIG_LUBBOCK,
365		CONFIG_INNOVATOROMAP1510,	CONFIG_INNOVATOROMAP1610
366		CONFIG_SHANNON,     CONFIG_SMDK2400,   CONFIG_SMDK2410,
367		CONFIG_TRAB,	    CONFIG_VCMA9,      CONFIG_AT91RM9200DK
368
369
370- CPU Module Type: (if CONFIG_COGENT is defined)
371		Define exactly one of
372		CONFIG_CMA286_60_OLD
373--- FIXME --- not tested yet:
374		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375		CONFIG_CMA287_23, CONFIG_CMA287_50
376
377- Motherboard Type: (if CONFIG_COGENT is defined)
378		Define exactly one of
379		CONFIG_CMA101, CONFIG_CMA102
380
381- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382		Define one or more of
383		CONFIG_CMA302
384
385- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386		Define one or more of
387		CONFIG_LCD_HEARTBEAT	- update a character position on
388					  the lcd display every second with
389					  a "rotator" |\-/|\-/
390
391- Board flavour: (if CONFIG_MPC8260ADS is defined)
392		CONFIG_ADSTYPE
393		Possible values are:
394			CFG_8260ADS	- original MPC8260ADS
395			CFG_8266ADS	- MPC8266ADS (untested)
396			CFG_PQ2FADS	- PQ2FADS-ZU
397
398
399- MPC824X Family Member (if CONFIG_MPC824X is defined)
400	Define exactly one of
401	CONFIG_MPC8240, CONFIG_MPC8245
402
403- 8xx CPU Options: (if using an 8xx cpu)
404		Define one or more of
405		CONFIG_8xx_GCLK_FREQ	- if get_gclk_freq() can not work e.g.
406					  no 32KHz reference PIT/RTC clock
407
408- Clock Interface:
409		CONFIG_CLOCKS_IN_MHZ
410
411		U-Boot stores all clock information in Hz
412		internally. For binary compatibility with older Linux
413		kernels (which expect the clocks passed in the
414		bd_info data to be in MHz) the environment variable
415		"clocks_in_mhz" can be defined so that U-Boot
416		converts clock data to MHZ before passing it to the
417		Linux kernel.
418
419		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
420		"clocks_in_mhz=1" is  automatically  included  in  the
421		default environment.
422
423- Console Interface:
424		Depending on board, define exactly one serial port
425		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
426		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
427		console by defining CONFIG_8xx_CONS_NONE
428
429		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
430		port routines must be defined elsewhere
431		(i.e. serial_init(), serial_getc(), ...)
432
433		CONFIG_CFB_CONSOLE
434		Enables console device for a color framebuffer. Needs following
435		defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
436			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
437						(default big endian)
438			VIDEO_HW_RECTFILL	graphic chip supports
439						rectangle fill
440						(cf. smiLynxEM)
441			VIDEO_HW_BITBLT		graphic chip supports
442						bit-blit (cf. smiLynxEM)
443			VIDEO_VISIBLE_COLS	visible pixel columns
444						(cols=pitch)
445			VIDEO_VISIBLE_ROWS      visible pixel rows
446			VIDEO_PIXEL_SIZE        bytes per pixel
447			VIDEO_DATA_FORMAT	graphic data format
448						(0-5, cf. cfb_console.c)
449			VIDEO_FB_ADRS           framebuffer address
450			VIDEO_KBD_INIT_FCT	keyboard int fct
451						(i.e. i8042_kbd_init())
452			VIDEO_TSTC_FCT		test char fct
453						(i.e. i8042_tstc)
454			VIDEO_GETC_FCT		get char fct
455						(i.e. i8042_getc)
456			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
457						(requires blink timer
458						cf. i8042.c)
459			CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
460			CONFIG_CONSOLE_TIME	display time/date info in
461						upper right corner
462						(requires CFG_CMD_DATE)
463			CONFIG_VIDEO_LOGO	display Linux logo in
464						upper left corner
465			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
466						linux_logo.h for logo.
467						Requires CONFIG_VIDEO_LOGO
468			CONFIG_CONSOLE_EXTRA_INFO
469						addional board info beside
470						the logo
471
472		When CONFIG_CFB_CONSOLE is defined, video console is
473		default i/o. Serial console can be forced with
474		environment 'console=serial'.
475
476- Console Baudrate:
477		CONFIG_BAUDRATE - in bps
478		Select one of the baudrates listed in
479		CFG_BAUDRATE_TABLE, see below.
480
481- Interrupt driven serial port input:
482		CONFIG_SERIAL_SOFTWARE_FIFO
483
484		PPC405GP only.
485		Use an interrupt handler for receiving data on the
486		serial port. It also enables using hardware handshake
487		(RTS/CTS) and UART's built-in FIFO. Set the number of
488		bytes the interrupt driven input buffer should have.
489
490		Set to 0 to disable this feature (this is the default).
491		This will also disable hardware handshake.
492
493- Console UART Number:
494		CONFIG_UART1_CONSOLE
495
496		IBM PPC4xx only.
497		If defined internal UART1 (and not UART0) is used
498		as default U-Boot console.
499
500- Boot Delay:	CONFIG_BOOTDELAY - in seconds
501		Delay before automatically booting the default image;
502		set to -1 to disable autoboot.
503
504		See doc/README.autoboot for these options that
505		work with CONFIG_BOOTDELAY. None are required.
506		CONFIG_BOOT_RETRY_TIME
507		CONFIG_BOOT_RETRY_MIN
508		CONFIG_AUTOBOOT_KEYED
509		CONFIG_AUTOBOOT_PROMPT
510		CONFIG_AUTOBOOT_DELAY_STR
511		CONFIG_AUTOBOOT_STOP_STR
512		CONFIG_AUTOBOOT_DELAY_STR2
513		CONFIG_AUTOBOOT_STOP_STR2
514		CONFIG_ZERO_BOOTDELAY_CHECK
515		CONFIG_RESET_TO_RETRY
516
517- Autoboot Command:
518		CONFIG_BOOTCOMMAND
519		Only needed when CONFIG_BOOTDELAY is enabled;
520		define a command string that is automatically executed
521		when no character is read on the console interface
522		within "Boot Delay" after reset.
523
524		CONFIG_BOOTARGS
525		This can be used to pass arguments to the bootm
526		command. The value of CONFIG_BOOTARGS goes into the
527		environment value "bootargs".
528
529		CONFIG_RAMBOOT and CONFIG_NFSBOOT
530		The value of these goes into the environment as
531		"ramboot" and "nfsboot" respectively, and can be used
532		as a convenience, when switching between booting from
533		ram and nfs.
534
535- Pre-Boot Commands:
536		CONFIG_PREBOOT
537
538		When this option is #defined, the existence of the
539		environment variable "preboot" will be checked
540		immediately before starting the CONFIG_BOOTDELAY
541		countdown and/or running the auto-boot command resp.
542		entering interactive mode.
543
544		This feature is especially useful when "preboot" is
545		automatically generated or modified. For an example
546		see the LWMON board specific code: here "preboot" is
547		modified when the user holds down a certain
548		combination of keys on the (special) keyboard when
549		booting the systems
550
551- Serial Download Echo Mode:
552		CONFIG_LOADS_ECHO
553		If defined to 1, all characters received during a
554		serial download (using the "loads" command) are
555		echoed back. This might be needed by some terminal
556		emulations (like "cu"), but may as well just take
557		time on others. This setting #define's the initial
558		value of the "loads_echo" environment variable.
559
560- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
561		CONFIG_KGDB_BAUDRATE
562		Select one of the baudrates listed in
563		CFG_BAUDRATE_TABLE, see below.
564
565- Monitor Functions:
566		CONFIG_COMMANDS
567		Most monitor functions can be selected (or
568		de-selected) by adjusting the definition of
569		CONFIG_COMMANDS; to select individual functions,
570		#define CONFIG_COMMANDS by "OR"ing any of the
571		following values:
572
573		#define enables commands:
574		-------------------------
575		CFG_CMD_ASKENV	* ask for env variable
576		CFG_CMD_AUTOSCRIPT Autoscript Support
577		CFG_CMD_BDI	  bdinfo
578		CFG_CMD_BEDBUG	  Include BedBug Debugger
579		CFG_CMD_BMP     * BMP support
580		CFG_CMD_BOOTD	  bootd
581		CFG_CMD_CACHE	  icache, dcache
582		CFG_CMD_CONSOLE	  coninfo
583		CFG_CMD_DATE	* support for RTC, date/time...
584		CFG_CMD_DHCP	  DHCP support
585		CFG_CMD_DIAG    * Diagnostics
586		CFG_CMD_DOC     * Disk-On-Chip Support
587		CFG_CMD_DTT       Digital Therm and Thermostat
588		CFG_CMD_ECHO	* echo arguments
589		CFG_CMD_EEPROM	* EEPROM read/write support
590		CFG_CMD_ELF	  bootelf, bootvx
591		CFG_CMD_ENV	  saveenv
592		CFG_CMD_FDC	* Floppy Disk Support
593		CFG_CMD_FAT	  FAT partition support
594		CFG_CMD_FDOS	* Dos diskette Support
595		CFG_CMD_FLASH	  flinfo, erase, protect
596		CFG_CMD_FPGA	  FPGA device initialization support
597		CFG_CMD_HWFLOW  * RTS/CTS hw flow control
598		CFG_CMD_I2C	* I2C serial bus support
599		CFG_CMD_IDE	* IDE harddisk support
600		CFG_CMD_IMI	  iminfo
601		CFG_CMD_IMLS      List all found images
602		CFG_CMD_IMMAP	* IMMR dump support
603		CFG_CMD_IRQ	* irqinfo
604		CFG_CMD_JFFS2   * JFFS2 Support
605		CFG_CMD_KGDB	* kgdb
606		CFG_CMD_LOADB	  loadb
607		CFG_CMD_LOADS	  loads
608		CFG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
609				  loop, mtest
610		CFG_CMD_MISC      Misc functions like sleep etc
611		CFG_CMD_MMC	  MMC memory mapped support
612		CFG_CMD_MII	  MII utility commands
613		CFG_CMD_NAND    * NAND support
614		CFG_CMD_NET	  bootp, tftpboot, rarpboot
615		CFG_CMD_PCI	* pciinfo
616		CFG_CMD_PCMCIA	* PCMCIA support
617		CFG_CMD_PING    * send ICMP ECHO_REQUEST to network host
618		CFG_CMD_PORTIO    Port I/O
619		CFG_CMD_REGINFO * Register dump
620		CFG_CMD_RUN	  run command in env variable
621		CFG_CMD_SAVES     save S record dump
622		CFG_CMD_SCSI	* SCSI Support
623		CFG_CMD_SDRAM   * print SDRAM configuration information
624		CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
625		CFG_CMD_SPI	* SPI serial bus support
626		CFG_CMD_USB	* USB support
627		CFG_CMD_VFD     * VFD support (TRAB)
628		CFG_CMD_BSP	* Board SPecific functions
629		-----------------------------------------------
630		CFG_CMD_ALL	all
631
632		CFG_CMD_DFL	Default configuration; at the moment
633				this is includes all commands, except
634				the ones marked with "*" in the list
635				above.
636
637		If you don't define CONFIG_COMMANDS it defaults to
638		CFG_CMD_DFL in include/cmd_confdefs.h. A board can
639		override the default settings in the respective
640		include file.
641
642		EXAMPLE: If you want all functions except of network
643		support you can write:
644
645		#define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
646
647
648	Note:	Don't enable the "icache" and "dcache" commands
649		(configuration option CFG_CMD_CACHE) unless you know
650		what you (and your U-Boot users) are doing. Data
651		cache cannot be enabled on systems like the 8xx or
652		8260 (where accesses to the IMMR region must be
653		uncached), and it cannot be disabled on all other
654		systems where we (mis-) use the data cache to hold an
655		initial stack and some data.
656
657
658		XXX - this list needs to get updated!
659
660- Watchdog:
661		CONFIG_WATCHDOG
662		If this variable is defined, it enables watchdog
663		support. There must be support in the platform specific
664		code for a watchdog. For the 8xx and 8260 CPUs, the
665		SIU Watchdog feature is enabled in the SYPCR
666		register.
667
668- U-Boot Version:
669		CONFIG_VERSION_VARIABLE
670		If this variable is defined, an environment variable
671		named "ver" is created by U-Boot showing the U-Boot
672		version as printed by the "version" command.
673		This variable is readonly.
674
675- Real-Time Clock:
676
677		When CFG_CMD_DATE is selected, the type of the RTC
678		has to be selected, too. Define exactly one of the
679		following options:
680
681		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
682		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
683		CONFIG_RTC_MC146818	- use MC146818 RTC
684		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
685		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
686		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
687		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
688
689		Note that if the RTC uses I2C, then the I2C interface
690		must also be configured. See I2C Support, below.
691
692- Timestamp Support:
693
694		When CONFIG_TIMESTAMP is selected, the timestamp
695		(date and time) of an image is printed by image
696		commands like bootm or iminfo. This option is
697		automatically enabled when you select CFG_CMD_DATE .
698
699- Partition Support:
700		CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
701		and/or CONFIG_ISO_PARTITION
702
703		If IDE or SCSI support	is  enabled  (CFG_CMD_IDE  or
704		CFG_CMD_SCSI) you must configure support for at least
705		one partition type as well.
706
707- IDE Reset method:
708		CONFIG_IDE_RESET_ROUTINE
709
710		Set this to define that instead of a reset Pin, the
711		routine ide_set_reset(int idereset) will be used.
712
713- ATAPI Support:
714		CONFIG_ATAPI
715
716		Set this to enable ATAPI support.
717
718- SCSI Support:
719		At the moment only there is only support for the
720		SYM53C8XX SCSI controller; define
721		CONFIG_SCSI_SYM53C8XX to enable it.
722
723		CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
724		CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
725		CFG_SCSI_MAX_LUN] can be adjusted to define the
726		maximum numbers of LUNs, SCSI ID's and target
727		devices.
728		CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
729
730- NETWORK Support (PCI):
731		CONFIG_E1000
732		Support for Intel 8254x gigabit chips.
733
734		CONFIG_EEPRO100
735		Support for Intel 82557/82559/82559ER chips.
736		Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
737		write routine for first time initialisation.
738
739		CONFIG_TULIP
740		Support for Digital 2114x chips.
741		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
742		modem chip initialisation (KS8761/QS6611).
743
744		CONFIG_NATSEMI
745		Support for National dp83815 chips.
746
747		CONFIG_NS8382X
748		Support for National dp8382[01] gigabit chips.
749
750- NETWORK Support (other):
751
752		CONFIG_DRIVER_LAN91C96
753		Support for SMSC's LAN91C96 chips.
754
755			CONFIG_LAN91C96_BASE
756			Define this to hold the physical address
757			of the LAN91C96's I/O space
758
759			CONFIG_LAN91C96_USE_32_BIT
760			Define this to enable 32 bit addressing
761
762- USB Support:
763		At the moment only the UHCI host controller is
764		supported (PIP405, MIP405); define
765		CONFIG_USB_UHCI to enable it.
766		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
767		end define CONFIG_USB_STORAGE to enable the USB
768		storage devices.
769		Note:
770		Supported are USB Keyboards and USB Floppy drives
771		(TEAC FD-05PUB).
772
773- MMC Support:
774		The MMC controller on the Intel PXA is supported. To
775		enable this define CONFIG_MMC. The MMC can be
776		accessed from the boot prompt by mapping the device
777		to physical memory similar to flash. Command line is
778		enabled with CFG_CMD_MMC. The MMC driver also works with
779		the FAT fs. This is enabled with CFG_CMD_FAT.
780
781- Keyboard Support:
782		CONFIG_ISA_KEYBOARD
783
784		Define this to enable standard (PC-Style) keyboard
785		support
786
787		CONFIG_I8042_KBD
788		Standard PC keyboard driver with US (is default) and
789		GERMAN key layout (switch via environment 'keymap=de') support.
790		Export function i8042_kbd_init, i8042_tstc and i8042_getc
791		for cfb_console. Supports cursor blinking.
792
793- Video support:
794		CONFIG_VIDEO
795
796		Define this to enable video support (for output to
797		video).
798
799		CONFIG_VIDEO_CT69000
800
801		Enable Chips & Technologies 69000 Video chip
802
803		CONFIG_VIDEO_SMI_LYNXEM
804		Enable Silicon Motion SMI 712/710/810 Video chip
805		Videomode are selected via environment 'videomode' with
806		standard LiLo mode numbers.
807		Following modes are supported  (* is default):
808
809			    800x600  1024x768  1280x1024
810	      256  (8bit)     303*      305       307
811	    65536 (16bit)     314       317       31a
812	16,7 Mill (24bit)     315       318       31b
813		(i.e. setenv videomode 317; saveenv; reset;)
814
815		CONFIG_VIDEO_SED13806
816		Enable Epson SED13806 driver. This driver supports 8bpp
817		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
818		or CONFIG_VIDEO_SED13806_16BPP
819
820- Keyboard Support:
821		CONFIG_KEYBOARD
822
823		Define this to enable a custom keyboard support.
824		This simply calls drv_keyboard_init() which must be
825		defined in your board-specific files.
826		The only board using this so far is RBC823.
827
828- LCD Support:	CONFIG_LCD
829
830		Define this to enable LCD support (for output to LCD
831		display); also select one of the supported displays
832		by defining one of these:
833
834		CONFIG_NEC_NL6648AC33:
835
836			NEC NL6648AC33-18. Active, color, single scan.
837
838		CONFIG_NEC_NL6648BC20
839
840			NEC NL6648BC20-08. 6.5", 640x480.
841			Active, color, single scan.
842
843		CONFIG_SHARP_16x9
844
845			Sharp 320x240. Active, color, single scan.
846			It isn't 16x9, and I am not sure what it is.
847
848		CONFIG_SHARP_LQ64D341
849
850			Sharp LQ64D341 display, 640x480.
851			Active, color, single scan.
852
853		CONFIG_HLD1045
854
855			HLD1045 display, 640x480.
856			Active, color, single scan.
857
858		CONFIG_OPTREX_BW
859
860			Optrex	 CBL50840-2 NF-FW 99 22 M5
861			or
862			Hitachi	 LMG6912RPFC-00T
863			or
864			Hitachi	 SP14Q002
865
866			320x240. Black & white.
867
868		Normally display is black on white background; define
869		CFG_WHITE_ON_BLACK to get it inverted.
870
871- Splash Screen Support: CONFIG_SPLASH_SCREEN
872
873		If this option is set, the environment is checked for
874		a variable "splashimage". If found, the usual display
875		of logo, copyright and system information on the LCD
876		is supressed and the BMP image at the address
877		specified in "splashimage" is loaded instead. The
878		console is redirected to the "nulldev", too. This
879		allows for a "silent" boot where a splash screen is
880		loaded very quickly after power-on.
881
882- Compression support:
883		CONFIG_BZIP2
884
885		If this option is set, support for bzip2 compressed
886		images is included. If not, only uncompressed and gzip
887		compressed images are supported.
888
889                NOTE: the bzip2 algorithm requires a lot of RAM, so
890                the malloc area (as defined by CFG_MALLOC_LEN) should
891                be at least 4MB.
892
893- Ethernet address:
894		CONFIG_ETHADDR
895		CONFIG_ETH2ADDR
896		CONFIG_ETH3ADDR
897
898		Define a default value for ethernet address to use
899		for the respective ethernet interface, in case this
900		is not determined automatically.
901
902- IP address:
903		CONFIG_IPADDR
904
905		Define a default value for the IP address to use for
906		the default ethernet interface, in case this is not
907		determined through e.g. bootp.
908
909- Server IP address:
910		CONFIG_SERVERIP
911
912		Defines a default value for theIP address of a TFTP
913		server to contact when using the "tftboot" command.
914
915- BOOTP Recovery Mode:
916		CONFIG_BOOTP_RANDOM_DELAY
917
918		If you have many targets in a network that try to
919		boot using BOOTP, you may want to avoid that all
920		systems send out BOOTP requests at precisely the same
921		moment (which would happen for instance at recovery
922		from a power failure, when all systems will try to
923		boot, thus flooding the BOOTP server. Defining
924		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
925		inserted before sending out BOOTP requests. The
926		following delays are insterted then:
927
928		1st BOOTP request:	delay 0 ... 1 sec
929		2nd BOOTP request:	delay 0 ... 2 sec
930		3rd BOOTP request:	delay 0 ... 4 sec
931		4th and following
932		BOOTP requests:		delay 0 ... 8 sec
933
934- DHCP Advanced Options:
935		CONFIG_BOOTP_MASK
936
937		You can fine tune the DHCP functionality by adding
938		these flags to the CONFIG_BOOTP_MASK define:
939
940		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
941		serverip from a DHCP server, it is possible that more
942		than one DNS serverip is offered to the client.
943		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
944		serverip will be stored in the additional environment
945		variable "dnsip2". The first DNS serverip is always
946		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
947		is added to the CONFIG_BOOTP_MASK.
948
949		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
950		to do a dynamic update of a DNS server. To do this, they
951		need the hostname of the DHCP requester.
952		If CONFIG_BOOP_SEND_HOSTNAME is added to the
953		CONFIG_BOOTP_MASK, the content of the "hostname"
954		environment variable is passed as option 12 to
955		the DHCP server.
956
957- Status LED:	CONFIG_STATUS_LED
958
959		Several configurations allow to display the current
960		status using a LED. For instance, the LED will blink
961		fast while running U-Boot code, stop blinking as
962		soon as a reply to a BOOTP request was received, and
963		start blinking slow once the Linux kernel is running
964		(supported by a status LED driver in the Linux
965		kernel). Defining CONFIG_STATUS_LED enables this
966		feature in U-Boot.
967
968- CAN Support:	CONFIG_CAN_DRIVER
969
970		Defining CONFIG_CAN_DRIVER enables CAN driver support
971		on those systems that support this (optional)
972		feature, like the TQM8xxL modules.
973
974- I2C Support:	CONFIG_HARD_I2C | CONFIG_SOFT_I2C
975
976		These enable I2C serial bus commands. Defining either of
977		(but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
978		include the appropriate I2C driver for the selected cpu.
979
980		This will allow you to use i2c commands at the u-boot
981		command line (as long as you set CFG_CMD_I2C in
982		CONFIG_COMMANDS) and communicate with i2c based realtime
983		clock chips. See common/cmd_i2c.c for a description of the
984		command line interface.
985
986		CONFIG_HARD_I2C	selects the CPM hardware driver for I2C.
987
988		CONFIG_SOFT_I2C configures u-boot to use a software (aka
989		bit-banging) driver instead of CPM or similar hardware
990		support for I2C.
991
992		There are several other quantities that must also be
993		defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
994
995		In both cases you will need to define CFG_I2C_SPEED
996		to be the frequency (in Hz) at which you wish your i2c bus
997		to run and CFG_I2C_SLAVE to be the address of this node (ie
998		the cpu's i2c node address).
999
1000		Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1001		sets the cpu up as a master node and so its address should
1002		therefore be cleared to 0 (See, eg, MPC823e User's Manual
1003		p.16-473). So, set CFG_I2C_SLAVE to 0.
1004
1005		That's all that's required for CONFIG_HARD_I2C.
1006
1007		If you use the software i2c interface (CONFIG_SOFT_I2C)
1008		then the following macros need to be defined (examples are
1009		from include/configs/lwmon.h):
1010
1011		I2C_INIT
1012
1013		(Optional). Any commands necessary to enable the I2C
1014		controller or configure ports.
1015
1016		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=  PB_SCL)
1017
1018		I2C_PORT
1019
1020		(Only for MPC8260 CPU). The I/O port to use (the code
1021		assumes both bits are on the same port). Valid values
1022		are 0..3 for ports A..D.
1023
1024		I2C_ACTIVE
1025
1026		The code necessary to make the I2C data line active
1027		(driven).  If the data line is open collector, this
1028		define can be null.
1029
1030		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)
1031
1032		I2C_TRISTATE
1033
1034		The code necessary to make the I2C data line tri-stated
1035		(inactive).  If the data line is open collector, this
1036		define can be null.
1037
1038		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1039
1040		I2C_READ
1041
1042		Code that returns TRUE if the I2C data line is high,
1043		FALSE if it is low.
1044
1045		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1046
1047		I2C_SDA(bit)
1048
1049		If <bit> is TRUE, sets the I2C data line high. If it
1050		is FALSE, it clears it (low).
1051
1052		eg: #define I2C_SDA(bit) \
1053			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
1054			else    immr->im_cpm.cp_pbdat &= ~PB_SDA
1055
1056		I2C_SCL(bit)
1057
1058		If <bit> is TRUE, sets the I2C clock line high. If it
1059		is FALSE, it clears it (low).
1060
1061		eg: #define I2C_SCL(bit) \
1062			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
1063			else    immr->im_cpm.cp_pbdat &= ~PB_SCL
1064
1065		I2C_DELAY
1066
1067		This delay is invoked four times per clock cycle so this
1068		controls the rate of data transfer.  The data rate thus
1069		is 1 / (I2C_DELAY * 4). Often defined to be something
1070		like:
1071
1072		#define I2C_DELAY  udelay(2)
1073
1074		CFG_I2C_INIT_BOARD
1075
1076		When a board is reset during an i2c bus transfer
1077		chips might think that the current transfer is still
1078		in progress. On some boards it is possible to access
1079		the i2c SCLK line directly, either by using the
1080		processor pin as a GPIO or by having a second pin
1081		connected to the bus. If this option is defined a
1082		custom i2c_init_board() routine in boards/xxx/board.c
1083		is run early in the boot sequence.
1084
1085- SPI Support:	CONFIG_SPI
1086
1087		Enables SPI driver (so far only tested with
1088		SPI EEPROM, also an instance works with Crystal A/D and
1089		D/As on the SACSng board)
1090
1091		CONFIG_SPI_X
1092
1093		Enables extended (16-bit) SPI EEPROM addressing.
1094		(symmetrical to CONFIG_I2C_X)
1095
1096		CONFIG_SOFT_SPI
1097
1098		Enables a software (bit-bang) SPI driver rather than
1099		using hardware support. This is a general purpose
1100		driver that only requires three general I/O port pins
1101		(two outputs, one input) to function. If this is
1102		defined, the board configuration must define several
1103		SPI configuration items (port pins to use, etc). For
1104		an example, see include/configs/sacsng.h.
1105
1106- FPGA Support: CONFIG_FPGA_COUNT
1107
1108		Specify the number of FPGA devices to support.
1109
1110		CONFIG_FPGA
1111
1112		Used to specify the types of FPGA devices. For
1113		example,
1114		#define CONFIG_FPGA  CFG_XILINX_VIRTEX2
1115
1116		CFG_FPGA_PROG_FEEDBACK
1117
1118		Enable printing of hash marks during FPGA
1119		configuration.
1120
1121		CFG_FPGA_CHECK_BUSY
1122
1123		Enable checks on FPGA configuration interface busy
1124		status by the configuration function. This option
1125		will require a board or device specific function to
1126		be written.
1127
1128		CONFIG_FPGA_DELAY
1129
1130		If defined, a function that provides delays in the
1131		FPGA configuration driver.
1132
1133		CFG_FPGA_CHECK_CTRLC
1134
1135		Allow Control-C to interrupt FPGA configuration
1136
1137		CFG_FPGA_CHECK_ERROR
1138
1139		Check for configuration errors during FPGA bitfile
1140		loading. For example, abort during Virtex II
1141		configuration if the INIT_B line goes low (which
1142		indicated a CRC error).
1143
1144		CFG_FPGA_WAIT_INIT
1145
1146		Maximum time to wait for the INIT_B line to deassert
1147		after PROB_B has been deasserted during a Virtex II
1148		FPGA configuration sequence. The default time is 500 mS.
1149
1150		CFG_FPGA_WAIT_BUSY
1151
1152		Maximum time to wait for BUSY to deassert during
1153		Virtex II FPGA configuration. The default is 5 mS.
1154
1155		CFG_FPGA_WAIT_CONFIG
1156
1157		Time to wait after FPGA configuration. The default is
1158		200 mS.
1159
1160- FPGA Support:	CONFIG_FPGA_COUNT
1161
1162		Specify the number of FPGA devices to support.
1163
1164		CONFIG_FPGA
1165
1166		Used to specify the types of FPGA devices.  For example,
1167		#define CONFIG_FPGA  CFG_XILINX_VIRTEX2
1168
1169		CFG_FPGA_PROG_FEEDBACK
1170
1171		Enable printing of hash marks during FPGA configuration.
1172
1173		CFG_FPGA_CHECK_BUSY
1174
1175		Enable checks on FPGA configuration interface busy
1176		status by the configuration function. This option
1177		will require a board or device specific function to
1178		be written.
1179
1180		CONFIG_FPGA_DELAY
1181
1182		If defined, a function that provides delays in the FPGA
1183		configuration driver.
1184
1185		CFG_FPGA_CHECK_CTRLC
1186		Allow Control-C to interrupt FPGA configuration
1187
1188		CFG_FPGA_CHECK_ERROR
1189
1190		Check for configuration errors during FPGA bitfile
1191		loading. For example, abort during Virtex II
1192		configuration if the INIT_B line goes low (which
1193		indicated a CRC error).
1194
1195		CFG_FPGA_WAIT_INIT
1196
1197		Maximum time to wait for the INIT_B line to deassert
1198		after PROB_B has been deasserted during a Virtex II
1199		FPGA configuration sequence. The default time is 500
1200		mS.
1201
1202		CFG_FPGA_WAIT_BUSY
1203
1204		Maximum time to wait for BUSY to deassert during
1205		Virtex II FPGA configuration. The default is 5 mS.
1206
1207		CFG_FPGA_WAIT_CONFIG
1208
1209		Time to wait after FPGA configuration. The default is
1210		200 mS.
1211
1212- Configuration Management:
1213		CONFIG_IDENT_STRING
1214
1215		If defined, this string will be added to the U-Boot
1216		version information (U_BOOT_VERSION)
1217
1218- Vendor Parameter Protection:
1219
1220		U-Boot considers the values of the environment
1221		variables "serial#" (Board Serial Number) and
1222		"ethaddr" (Ethernet Address) to be parameters that
1223		are set once by the board vendor / manufacturer, and
1224		protects these variables from casual modification by
1225		the user. Once set, these variables are read-only,
1226		and write or delete attempts are rejected. You can
1227		change this behviour:
1228
1229		If CONFIG_ENV_OVERWRITE is #defined in your config
1230		file, the write protection for vendor parameters is
1231		completely disabled. Anybody can change or delete
1232		these parameters.
1233
1234		Alternatively, if you #define _both_ CONFIG_ETHADDR
1235		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1236		ethernet address is installed in the environment,
1237		which can be changed exactly ONCE by the user. [The
1238		serial# is unaffected by this, i. e. it remains
1239		read-only.]
1240
1241- Protected RAM:
1242		CONFIG_PRAM
1243
1244		Define this variable to enable the reservation of
1245		"protected RAM", i. e. RAM which is not overwritten
1246		by U-Boot. Define CONFIG_PRAM to hold the number of
1247		kB you want to reserve for pRAM. You can overwrite
1248		this default value by defining an environment
1249		variable "pram" to the number of kB you want to
1250		reserve. Note that the board info structure will
1251		still show the full amount of RAM. If pRAM is
1252		reserved, a new environment variable "mem" will
1253		automatically be defined to hold the amount of
1254		remaining RAM in a form that can be passed as boot
1255		argument to Linux, for instance like that:
1256
1257			setenv bootargs ... mem=\$(mem)
1258			saveenv
1259
1260		This way you can tell Linux not to use this memory,
1261		either, which results in a memory region that will
1262		not be affected by reboots.
1263
1264		*WARNING* If your board configuration uses automatic
1265		detection of the RAM size, you must make sure that
1266		this memory test is non-destructive. So far, the
1267		following board configurations are known to be
1268		"pRAM-clean":
1269
1270			ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1271			HERMES, IP860, RPXlite, LWMON, LANTEC,
1272			PCU_E, FLAGADM, TQM8260
1273
1274- Error Recovery:
1275		CONFIG_PANIC_HANG
1276
1277		Define this variable to stop the system in case of a
1278		fatal error, so that you have to reset it manually.
1279		This is probably NOT a good idea for an embedded
1280		system where you want to system to reboot
1281		automatically as fast as possible, but it may be
1282		useful during development since you can try to debug
1283		the conditions that lead to the situation.
1284
1285		CONFIG_NET_RETRY_COUNT
1286
1287		This variable defines the number of retries for
1288		network operations like ARP, RARP, TFTP, or BOOTP
1289		before giving up the operation. If not defined, a
1290		default value of 5 is used.
1291
1292- Command Interpreter:
1293		CFG_HUSH_PARSER
1294
1295		Define this variable to enable the "hush" shell (from
1296		Busybox) as command line interpreter, thus enabling
1297		powerful command line syntax like
1298		if...then...else...fi conditionals or `&&' and '||'
1299		constructs ("shell scripts").
1300
1301		If undefined, you get the old, much simpler behaviour
1302		with a somewhat smaller memory footprint.
1303
1304
1305		CFG_PROMPT_HUSH_PS2
1306
1307		This defines the secondary prompt string, which is
1308		printed when the command interpreter needs more input
1309		to complete a command. Usually "> ".
1310
1311	Note:
1312
1313		In the current implementation, the local variables
1314		space and global environment variables space are
1315		separated. Local variables are those you define by
1316		simply typing `name=value'. To access a local
1317		variable later on, you have write `$name' or
1318		`${name}'; to execute the contents of a variable
1319		directly type `$name' at the command prompt.
1320
1321		Global environment variables are those you use
1322		setenv/printenv to work with. To run a command stored
1323		in such a variable, you need to use the run command,
1324		and you must not use the '$' sign to access them.
1325
1326		To store commands and special characters in a
1327		variable, please use double quotation marks
1328		surrounding the whole text of the variable, instead
1329		of the backslashes before semicolons and special
1330		symbols.
1331
1332- Default Environment
1333		CONFIG_EXTRA_ENV_SETTINGS
1334
1335		Define this to contain any number of null terminated
1336		strings (variable = value pairs) that will be part of
1337		the default environment compiled into the boot image.
1338
1339		For example, place something like this in your
1340		board's config file:
1341
1342		#define CONFIG_EXTRA_ENV_SETTINGS \
1343			"myvar1=value1\0" \
1344			"myvar2=value2\0"
1345
1346		Warning: This method is based on knowledge about the
1347		internal format how the environment is stored by the
1348		U-Boot code. This is NOT an official, exported
1349		interface! Although it is unlikely that this format
1350		will change soon, there is no guarantee either.
1351		You better know what you are doing here.
1352
1353		Note: overly (ab)use of the default environment is
1354		discouraged. Make sure to check other ways to preset
1355		the environment like the autoscript function or the
1356		boot command first.
1357
1358- DataFlash Support
1359		CONFIG_HAS_DATAFLASH
1360
1361		Defining this option enables DataFlash features and
1362		allows to read/write in Dataflash via the standard
1363		commands cp, md...
1364
1365- Show boot progress
1366		CONFIG_SHOW_BOOT_PROGRESS
1367
1368		Defining this option allows to add some board-
1369		specific code (calling a user-provided function
1370		"show_boot_progress(int)") that enables you to show
1371		the system's boot progress on some display (for
1372		example, some LED's) on your board. At the moment,
1373		the following checkpoints are implemented:
1374
1375  Arg	Where			When
1376    1	common/cmd_bootm.c	before attempting to boot an image
1377   -1	common/cmd_bootm.c	Image header has bad     magic number
1378    2	common/cmd_bootm.c	Image header has correct magic number
1379   -2	common/cmd_bootm.c	Image header has bad     checksum
1380    3	common/cmd_bootm.c	Image header has correct checksum
1381   -3	common/cmd_bootm.c	Image data   has bad     checksum
1382    4	common/cmd_bootm.c	Image data   has correct checksum
1383   -4	common/cmd_bootm.c	Image is for unsupported architecture
1384    5	common/cmd_bootm.c	Architecture check OK
1385   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi, standalone)
1386    6	common/cmd_bootm.c	Image Type check OK
1387   -6	common/cmd_bootm.c	gunzip uncompression error
1388   -7	common/cmd_bootm.c	Unimplemented compression type
1389    7	common/cmd_bootm.c	Uncompression OK
1390   -8	common/cmd_bootm.c	Wrong Image Type (not kernel, multi, standalone)
1391    8	common/cmd_bootm.c	Image Type check OK
1392   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)
1393    9	common/cmd_bootm.c	Start initial ramdisk verification
1394  -10	common/cmd_bootm.c	Ramdisk header has bad     magic number
1395  -11	common/cmd_bootm.c	Ramdisk header has bad     checksum
1396   10	common/cmd_bootm.c	Ramdisk header is OK
1397  -12	common/cmd_bootm.c	Ramdisk data   has bad     checksum
1398   11	common/cmd_bootm.c	Ramdisk data   has correct checksum
1399   12	common/cmd_bootm.c	Ramdisk verification complete, start loading
1400  -13	common/cmd_bootm.c	Wrong Image Type (not PPC Linux Ramdisk)
1401   13	common/cmd_bootm.c	Start multifile image verification
1402   14	common/cmd_bootm.c	No initial ramdisk, no multifile, continue.
1403   15	common/cmd_bootm.c	All preparation done, transferring control to OS
1404
1405   -1	common/cmd_doc.c	Bad usage of "doc" command
1406   -1	common/cmd_doc.c	No boot device
1407   -1	common/cmd_doc.c	Unknown Chip ID on boot device
1408   -1	common/cmd_doc.c	Read Error on boot device
1409   -1	common/cmd_doc.c	Image header has bad magic number
1410
1411   -1	common/cmd_ide.c	Bad usage of "ide" command
1412   -1	common/cmd_ide.c	No boot device
1413   -1	common/cmd_ide.c	Unknown boot device
1414   -1	common/cmd_ide.c	Unknown partition table
1415   -1	common/cmd_ide.c	Invalid partition type
1416   -1	common/cmd_ide.c	Read Error on boot device
1417   -1	common/cmd_ide.c	Image header has bad magic number
1418
1419   -1	common/cmd_nand.c	Bad usage of "nand" command
1420   -1	common/cmd_nand.c	No boot device
1421   -1	common/cmd_nand.c	Unknown Chip ID on boot device
1422   -1	common/cmd_nand.c	Read Error on boot device
1423   -1	common/cmd_nand.c	Image header has bad magic number
1424
1425   -1	common/env_common.c     Environment has a bad CRC, using default
1426
1427
1428Modem Support:
1429--------------
1430
1431[so far only for SMDK2400 and TRAB boards]
1432
1433- Modem support endable:
1434		CONFIG_MODEM_SUPPORT
1435
1436- RTS/CTS Flow control enable:
1437		CONFIG_HWFLOW
1438
1439- Modem debug support:
1440		CONFIG_MODEM_SUPPORT_DEBUG
1441
1442		Enables debugging stuff (char screen[1024], dbg())
1443		for modem support. Useful only with BDI2000.
1444
1445- General:
1446
1447		In the target system modem support is enabled when a
1448		specific key (key combination) is pressed during
1449		power-on. Otherwise U-Boot will boot normally
1450		(autoboot). The key_pressed() fuction is called from
1451		board_init(). Currently key_pressed() is a dummy
1452		function, returning 1 and thus enabling modem
1453		initialization.
1454
1455		If there are no modem init strings in the
1456		environment, U-Boot proceed to autoboot; the
1457		previous output (banner, info printfs) will be
1458		supressed, though.
1459
1460		See also: doc/README.Modem
1461
1462
1463Configuration Settings:
1464-----------------------
1465
1466- CFG_LONGHELP: Defined when you want long help messages included;
1467		undefine this when you're short of memory.
1468
1469- CFG_PROMPT:	This is what U-Boot prints on the console to
1470		prompt for user input.
1471
1472- CFG_CBSIZE:	Buffer size for input from the Console
1473
1474- CFG_PBSIZE:	Buffer size for Console output
1475
1476- CFG_MAXARGS:	max. Number of arguments accepted for monitor commands
1477
1478- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1479		the application (usually a Linux kernel) when it is
1480		booted
1481
1482- CFG_BAUDRATE_TABLE:
1483		List of legal baudrate settings for this board.
1484
1485- CFG_CONSOLE_INFO_QUIET
1486		Suppress display of console information at boot.
1487
1488- CFG_CONSOLE_IS_IN_ENV
1489		If the board specific function
1490			extern int overwrite_console (void);
1491		returns 1, the stdin, stderr and stdout are switched to the
1492		serial port, else the settings in the environment are used.
1493
1494- CFG_CONSOLE_OVERWRITE_ROUTINE
1495		Enable the call to overwrite_console().
1496
1497- CFG_CONSOLE_ENV_OVERWRITE
1498		Enable overwrite of previous console environment settings.
1499
1500- CFG_MEMTEST_START, CFG_MEMTEST_END:
1501		Begin and End addresses of the area used by the
1502		simple memory test.
1503
1504- CFG_ALT_MEMTEST:
1505		Enable an alternate, more extensive memory test.
1506
1507- CFG_MEMTEST_SCRATCH:
1508		Scratch address used by the alternate memory test
1509		You only need to set this if address zero isn't writeable
1510
1511- CFG_TFTP_LOADADDR:
1512		Default load address for network file downloads
1513
1514- CFG_LOADS_BAUD_CHANGE:
1515		Enable temporary baudrate change while serial download
1516
1517- CFG_SDRAM_BASE:
1518		Physical start address of SDRAM. _Must_ be 0 here.
1519
1520- CFG_MBIO_BASE:
1521		Physical start address of Motherboard I/O (if using a
1522		Cogent motherboard)
1523
1524- CFG_FLASH_BASE:
1525		Physical start address of Flash memory.
1526
1527- CFG_MONITOR_BASE:
1528		Physical start address of boot monitor code (set by
1529		make config files to be same as the text base address
1530		(TEXT_BASE) used when linking) - same as
1531		CFG_FLASH_BASE when booting from flash.
1532
1533- CFG_MONITOR_LEN:
1534		Size of memory reserved for monitor code, used to
1535		determine _at_compile_time_ (!) if the environment is
1536		embedded within the U-Boot image, or in a separate
1537		flash sector.
1538
1539- CFG_MALLOC_LEN:
1540		Size of DRAM reserved for malloc() use.
1541
1542- CFG_BOOTMAPSZ:
1543		Maximum size of memory mapped by the startup code of
1544		the Linux kernel; all data that must be processed by
1545		the Linux kernel (bd_info, boot arguments, eventually
1546		initrd image) must be put below this limit.
1547
1548- CFG_MAX_FLASH_BANKS:
1549		Max number of Flash memory banks
1550
1551- CFG_MAX_FLASH_SECT:
1552		Max number of sectors on a Flash chip
1553
1554- CFG_FLASH_ERASE_TOUT:
1555		Timeout for Flash erase operations (in ms)
1556
1557- CFG_FLASH_WRITE_TOUT:
1558		Timeout for Flash write operations (in ms)
1559
1560- CFG_FLASH_LOCK_TOUT
1561		Timeout for Flash set sector lock bit operation (in ms)
1562
1563- CFG_FLASH_UNLOCK_TOUT
1564		Timeout for Flash clear lock bits operation (in ms)
1565
1566- CFG_FLASH_PROTECTION
1567		If defined, hardware flash sectors protection is used
1568		instead of U-Boot software protection.
1569
1570- CFG_DIRECT_FLASH_TFTP:
1571
1572		Enable TFTP transfers directly to flash memory;
1573		without this option such a download has to be
1574		performed in two steps: (1) download to RAM, and (2)
1575		copy from RAM to flash.
1576
1577		The two-step approach is usually more reliable, since
1578		you can check if the download worked before you erase
1579		the flash, but in some situations (when sytem RAM is
1580		too limited to allow for a tempory copy of the
1581		downloaded image) this option may be very useful.
1582
1583- CFG_FLASH_CFI:
1584		Define if the flash driver uses extra elements in the
1585		common flash structure for storing flash geometry
1586
1587- CFG_RX_ETH_BUFFER:
1588		Defines the number of ethernet receive buffers. On some
1589		ethernet controllers it is recommended to set this value
1590		to 8 or even higher (EEPRO100 or 405 EMAC), since all
1591		buffers can be full shortly after enabling the interface
1592		on high ethernet traffic.
1593		Defaults to 4 if not defined.
1594
1595The following definitions that deal with the placement and management
1596of environment data (variable area); in general, we support the
1597following configurations:
1598
1599- CFG_ENV_IS_IN_FLASH:
1600
1601	Define this if the environment is in flash memory.
1602
1603	a) The environment occupies one whole flash sector, which is
1604	   "embedded" in the text segment with the U-Boot code. This
1605	   happens usually with "bottom boot sector" or "top boot
1606	   sector" type flash chips, which have several smaller
1607	   sectors at the start or the end. For instance, such a
1608	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1609	   such a case you would place the environment in one of the
1610	   4 kB sectors - with U-Boot code before and after it. With
1611	   "top boot sector" type flash chips, you would put the
1612	   environment in one of the last sectors, leaving a gap
1613	   between U-Boot and the environment.
1614
1615	- CFG_ENV_OFFSET:
1616
1617	   Offset of environment data (variable area) to the
1618	   beginning of flash memory; for instance, with bottom boot
1619	   type flash chips the second sector can be used: the offset
1620	   for this sector is given here.
1621
1622	   CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1623
1624	- CFG_ENV_ADDR:
1625
1626	   This is just another way to specify the start address of
1627	   the flash sector containing the environment (instead of
1628	   CFG_ENV_OFFSET).
1629
1630	- CFG_ENV_SECT_SIZE:
1631
1632	   Size of the sector containing the environment.
1633
1634
1635	b) Sometimes flash chips have few, equal sized, BIG sectors.
1636	   In such a case you don't want to spend a whole sector for
1637	   the environment.
1638
1639	- CFG_ENV_SIZE:
1640
1641	   If you use this in combination with CFG_ENV_IS_IN_FLASH
1642	   and CFG_ENV_SECT_SIZE, you can specify to use only a part
1643	   of this flash sector for the environment. This saves
1644	   memory for the RAM copy of the environment.
1645
1646	   It may also save flash memory if you decide to use this
1647	   when your environment is "embedded" within U-Boot code,
1648	   since then the remainder of the flash sector could be used
1649	   for U-Boot code. It should be pointed out that this is
1650	   STRONGLY DISCOURAGED from a robustness point of view:
1651	   updating the environment in flash makes it always
1652	   necessary to erase the WHOLE sector. If something goes
1653	   wrong before the contents has been restored from a copy in
1654	   RAM, your target system will be dead.
1655
1656	- CFG_ENV_ADDR_REDUND
1657	  CFG_ENV_SIZE_REDUND
1658
1659	   These settings describe a second storage area used to hold
1660	   a redundand copy of the environment data, so that there is
1661	   a valid backup copy in case there is a power failure during
1662	   a "saveenv" operation.
1663
1664BE CAREFUL! Any changes to the flash layout, and some changes to the
1665source code will make it necessary to adapt <board>/u-boot.lds*
1666accordingly!
1667
1668
1669- CFG_ENV_IS_IN_NVRAM:
1670
1671	Define this if you have some non-volatile memory device
1672	(NVRAM, battery buffered SRAM) which you want to use for the
1673	environment.
1674
1675	- CFG_ENV_ADDR:
1676	- CFG_ENV_SIZE:
1677
1678	  These two #defines are used to determin the memory area you
1679	  want to use for environment. It is assumed that this memory
1680	  can just be read and written to, without any special
1681	  provision.
1682
1683BE CAREFUL! The first access to the environment happens quite early
1684in U-Boot initalization (when we try to get the setting of for the
1685console baudrate). You *MUST* have mappend your NVRAM area then, or
1686U-Boot will hang.
1687
1688Please note that even with NVRAM we still use a copy of the
1689environment in RAM: we could work on NVRAM directly, but we want to
1690keep settings there always unmodified except somebody uses "saveenv"
1691to save the current settings.
1692
1693
1694- CFG_ENV_IS_IN_EEPROM:
1695
1696	Use this if you have an EEPROM or similar serial access
1697	device and a driver for it.
1698
1699	- CFG_ENV_OFFSET:
1700	- CFG_ENV_SIZE:
1701
1702	  These two #defines specify the offset and size of the
1703	  environment area within the total memory of your EEPROM.
1704
1705	- CFG_I2C_EEPROM_ADDR:
1706	  If defined, specified the chip address of the EEPROM device.
1707	  The default address is zero.
1708
1709	- CFG_EEPROM_PAGE_WRITE_BITS:
1710	  If defined, the number of bits used to address bytes in a
1711	  single page in the EEPROM device.  A 64 byte page, for example
1712	  would require six bits.
1713
1714	- CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1715	  If defined, the number of milliseconds to delay between
1716	  page writes.  The default is zero milliseconds.
1717
1718	- CFG_I2C_EEPROM_ADDR_LEN:
1719	  The length in bytes of the EEPROM memory array address.  Note
1720	  that this is NOT the chip address length!
1721
1722	- CFG_EEPROM_SIZE:
1723	  The size in bytes of the EEPROM device.
1724
1725
1726- CFG_SPI_INIT_OFFSET
1727
1728	Defines offset to the initial SPI buffer area in DPRAM. The
1729	area is used at an early stage (ROM part) if the environment
1730	is configured to reside in the SPI EEPROM: We need a 520 byte
1731	scratch DPRAM area. It is used between the two initialization
1732	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1733	to be a good choice since it makes it far enough from the
1734	start of the data area as well as from the stack pointer.
1735
1736Please note that the environment is read-only as long as the monitor
1737has been relocated to RAM and a RAM copy of the environment has been
1738created; also, when using EEPROM you will have to use getenv_r()
1739until then to read environment variables.
1740
1741The environment is protected by a CRC32 checksum. Before the monitor
1742is relocated into RAM, as a result of a bad CRC you will be working
1743with the compiled-in default environment - *silently*!!! [This is
1744necessary, because the first environment variable we need is the
1745"baudrate" setting for the console - if we have a bad CRC, we don't
1746have any device yet where we could complain.]
1747
1748Note: once the monitor has been relocated, then it will complain if
1749the default environment is used; a new CRC is computed as soon as you
1750use the "saveenv" command to store a valid environment.
1751
1752- CFG_FAULT_ECHO_LINK_DOWN:
1753	        Echo the inverted Ethernet link state to the fault LED.
1754
1755		Note: If this option is active, then CFG_FAULT_MII_ADDR
1756		      also needs to be defined.
1757
1758- CFG_FAULT_MII_ADDR:
1759	        MII address of the PHY to check for the Ethernet link state.
1760
1761Low Level (hardware related) configuration options:
1762---------------------------------------------------
1763
1764- CFG_CACHELINE_SIZE:
1765		Cache Line Size of the CPU.
1766
1767- CFG_DEFAULT_IMMR:
1768		Default address of the IMMR after system reset.
1769
1770                Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1771                and RPXsuper) to be able to adjust the position of
1772                the IMMR register after a reset.
1773
1774- Floppy Disk Support:
1775		CFG_FDC_DRIVE_NUMBER
1776
1777		the default drive number (default value 0)
1778
1779		CFG_ISA_IO_STRIDE
1780
1781		defines the spacing between fdc chipset registers
1782		(default value 1)
1783
1784		CFG_ISA_IO_OFFSET
1785
1786		defines the offset of register from address. It
1787		depends on which part of the data bus is connected to
1788		the fdc chipset. (default value 0)
1789
1790		If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1791		CFG_FDC_DRIVE_NUMBER are undefined, they take their
1792		default value.
1793
1794		if CFG_FDC_HW_INIT is defined, then the function
1795		fdc_hw_init() is called at the beginning of the FDC
1796		setup. fdc_hw_init() must be provided by the board
1797		source code. It is used to make hardware dependant
1798		initializations.
1799
1800- CFG_IMMR:	Physical address of the Internal Memory Mapped
1801		Register; DO NOT CHANGE! (11-4)
1802		[MPC8xx systems only]
1803
1804- CFG_INIT_RAM_ADDR:
1805
1806		Start address of memory area that can be used for
1807		initial data and stack; please note that this must be
1808		writable memory that is working WITHOUT special
1809		initialization, i. e. you CANNOT use normal RAM which
1810		will become available only after programming the
1811		memory controller and running certain initialization
1812		sequences.
1813
1814		U-Boot uses the following memory types:
1815		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1816		- MPC824X: data cache
1817		- PPC4xx:  data cache
1818
1819- CFG_GBL_DATA_OFFSET:
1820
1821		Offset of the initial data structure in the memory
1822		area defined by CFG_INIT_RAM_ADDR. Usually
1823		CFG_GBL_DATA_OFFSET is chosen such that the initial
1824		data is located at the end of the available space
1825		(sometimes written as (CFG_INIT_RAM_END -
1826		CFG_INIT_DATA_SIZE), and the initial stack is just
1827		below that area (growing from (CFG_INIT_RAM_ADDR +
1828		CFG_GBL_DATA_OFFSET) downward.
1829
1830	Note:
1831		On the MPC824X (or other systems that use the data
1832		cache for initial memory) the address chosen for
1833		CFG_INIT_RAM_ADDR is basically arbitrary - it must
1834		point to an otherwise UNUSED address space between
1835		the top of RAM and the start of the PCI space.
1836
1837- CFG_SIUMCR:	SIU Module Configuration (11-6)
1838
1839- CFG_SYPCR:	System Protection Control (11-9)
1840
1841- CFG_TBSCR:	Time Base Status and Control (11-26)
1842
1843- CFG_PISCR:	Periodic Interrupt Status and Control (11-31)
1844
1845- CFG_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)
1846
1847- CFG_SCCR:	System Clock and reset Control Register (15-27)
1848
1849- CFG_OR_TIMING_SDRAM:
1850		SDRAM timing
1851
1852- CFG_MAMR_PTA:
1853		periodic timer for refresh
1854
1855- CFG_DER:	Debug Event Register (37-47)
1856
1857- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1858  CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1859  CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1860  CFG_BR1_PRELIM:
1861		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1862
1863- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1864  CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1865  CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1866		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1867
1868- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1869  CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1870		Machine Mode Register and Memory Periodic Timer
1871		Prescaler definitions (SDRAM timing)
1872
1873- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1874		enable I2C microcode relocation patch (MPC8xx);
1875		define relocation offset in DPRAM [DSP2]
1876
1877- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1878		enable SPI microcode relocation patch (MPC8xx);
1879		define relocation offset in DPRAM [SCC4]
1880
1881- CFG_USE_OSCCLK:
1882		Use OSCM clock mode on MBX8xx board. Be careful,
1883		wrong setting might damage your board. Read
1884		doc/README.MBX before setting this variable!
1885
1886- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1887		Offset of the bootmode word in DPRAM used by post
1888		(Power On Self Tests). This definition overrides
1889		#define'd default value in commproc.h resp.
1890		cpm_8260.h.
1891
1892- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1893  CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1894  CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1895  CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1896  CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1897  CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1898  CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1899  CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1900		Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1901
1902Building the Software:
1903======================
1904
1905Building U-Boot has been tested in native PPC environments (on a
1906PowerBook G3 running LinuxPPC 2000) and in cross environments
1907(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1908NetBSD 1.5 on x86).
1909
1910If you are not using a native PPC environment, it is assumed that you
1911have the GNU cross compiling tools available in your path and named
1912with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1913you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1914the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1915change it to:
1916
1917	CROSS_COMPILE = ppc_4xx-
1918
1919
1920U-Boot is intended to be  simple  to  build.  After  installing  the
1921sources	 you must configure U-Boot for one specific board type. This
1922is done by typing:
1923
1924	make NAME_config
1925
1926where "NAME_config" is the name of one of the existing
1927configurations; the following names are supported:
1928
1929    ADCIOP_config	  GTH_config		TQM850L_config
1930    ADS860_config	  IP860_config		TQM855L_config
1931    AR405_config	  IVML24_config		TQM860L_config
1932    CANBT_config	  IVMS8_config		WALNUT405_config
1933    CPCI405_config	  LANTEC_config		cogent_common_config
1934    CPCIISER4_config	  MBX_config		cogent_mpc8260_config
1935    CU824_config	  MBX860T_config	cogent_mpc8xx_config
1936    ESTEEM192E_config	  RPXlite_config	hermes_config
1937    ETX094_config	  RPXsuper_config	hymod_config
1938    FADS823_config	  SM850_config		lwmon_config
1939    FADS850SAR_config	  SPD823TS_config	pcu_e_config
1940    FADS860T_config	  SXNI855T_config	rsdproto_config
1941    FPS850L_config	  Sandpoint8240_config	sbc8260_config
1942    GENIETV_config	  TQM823L_config	PIP405_config
1943    GEN860T_config	  EBONY_config		FPS860L_config
1944    ELPT860_config	  cmi_mpc5xx_config	NETVIA_config
1945    at91rm9200dk_config	  omap1510inn_config	MPC8260ADS_config
1946    omap1610inn_config
1947Note: for some board special configuration names may exist; check  if
1948      additional  information is available from the board vendor; for
1949      instance, the TQM8xxL systems run normally at 50 MHz and use  a
1950      SCC  for	10baseT	 ethernet; there are also systems with 80 MHz
1951      CPU clock, and an optional Fast Ethernet	module	is  available
1952      for  CPU's  with FEC. You can select such additional "features"
1953      when chosing the configuration, i. e.
1954
1955      make TQM860L_config
1956	- will configure for a plain TQM860L, i. e. 50MHz, no FEC
1957
1958      make TQM860L_FEC_config
1959	- will configure for a TQM860L at 50MHz with FEC for ethernet
1960
1961      make TQM860L_80MHz_config
1962	- will configure for a TQM860L at 80 MHz, with normal 10baseT
1963	  interface
1964
1965      make TQM860L_FEC_80MHz_config
1966	- will configure for a TQM860L at 80 MHz with FEC for ethernet
1967
1968      make TQM823L_LCD_config
1969	- will configure for a TQM823L with U-Boot console on LCD
1970
1971      make TQM823L_LCD_80MHz_config
1972	- will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1973
1974      etc.
1975
1976
1977Finally, type "make all", and you should get some working U-Boot
1978images ready for download to / installation on your system:
1979
1980- "u-boot.bin" is a raw binary image
1981- "u-boot" is an image in ELF binary format
1982- "u-boot.srec" is in Motorola S-Record format
1983
1984
1985Please be aware that the Makefiles assume you are using GNU make, so
1986for instance on NetBSD you might need to use "gmake" instead of
1987native "make".
1988
1989
1990If the system board that you have is not listed, then you will need
1991to port U-Boot to your hardware platform. To do this, follow these
1992steps:
1993
19941.  Add a new configuration option for your board to the toplevel
1995    "Makefile" and to the "MAKEALL" script, using the existing
1996    entries as examples. Note that here and at many other places
1997    boards and other names are listed in alphabetical sort order. Please
1998    keep this order.
19992.  Create a new directory to hold your board specific code. Add any
2000    files you need. In your board directory, you will need at least
2001    the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
20023.  Create a new configuration file "include/configs/<board>.h" for
2003    your board
20043.  If you're porting U-Boot to a new CPU, then also create a new
2005    directory to hold your CPU specific code. Add any files you need.
20064.  Run "make <board>_config" with your new name.
20075.  Type "make", and you should get a working "u-boot.srec" file
2008    to be installed on your target system.
20096.  Debug and solve any problems that might arise.
2010    [Of course, this last step is much harder than it sounds.]
2011
2012
2013Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2014==============================================================
2015
2016If you have modified U-Boot sources (for instance added a new	board
2017or  support  for  new  devices,	 a new CPU, etc.) you are expected to
2018provide feedback to the other developers. The feedback normally takes
2019the form of a "patch", i. e. a context diff against a certain (latest
2020official or latest in CVS) version of U-Boot sources.
2021
2022But before you submit such a patch, please verify that	your  modifi-
2023cation	did not break existing code. At least make sure that *ALL* of
2024the supported boards compile WITHOUT ANY compiler warnings. To do so,
2025just run the "MAKEALL" script, which will configure and build U-Boot
2026for ALL supported system. Be warned, this will take a while. You  can
2027select	which  (cross)	compiler  to use by passing a `CROSS_COMPILE'
2028environment variable to the script, i. e. to use the cross tools from
2029MontaVista's Hard Hat Linux you can type
2030
2031	CROSS_COMPILE=ppc_8xx- MAKEALL
2032
2033or to build on a native PowerPC system you can type
2034
2035	CROSS_COMPILE=' ' MAKEALL
2036
2037See also "U-Boot Porting Guide" below.
2038
2039
2040Monitor Commands - Overview:
2041============================
2042
2043go	- start application at address 'addr'
2044run	- run commands in an environment variable
2045bootm	- boot application image from memory
2046bootp	- boot image via network using BootP/TFTP protocol
2047tftpboot- boot image via network using TFTP protocol
2048	       and env variables "ipaddr" and "serverip"
2049	       (and eventually "gatewayip")
2050rarpboot- boot image via network using RARP/TFTP protocol
2051diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
2052loads	- load S-Record file over serial line
2053loadb	- load binary file over serial line (kermit mode)
2054md	- memory display
2055mm	- memory modify (auto-incrementing)
2056nm	- memory modify (constant address)
2057mw	- memory write (fill)
2058cp	- memory copy
2059cmp	- memory compare
2060crc32	- checksum calculation
2061imd     - i2c memory display
2062imm     - i2c memory modify (auto-incrementing)
2063inm     - i2c memory modify (constant address)
2064imw     - i2c memory write (fill)
2065icrc32  - i2c checksum calculation
2066iprobe  - probe to discover valid I2C chip addresses
2067iloop   - infinite loop on address range
2068isdram  - print SDRAM configuration information
2069sspi    - SPI utility commands
2070base	- print or set address offset
2071printenv- print environment variables
2072setenv	- set environment variables
2073saveenv - save environment variables to persistent storage
2074protect - enable or disable FLASH write protection
2075erase	- erase FLASH memory
2076flinfo	- print FLASH memory information
2077bdinfo	- print Board Info structure
2078iminfo	- print header information for application image
2079coninfo - print console devices and informations
2080ide	- IDE sub-system
2081loop	- infinite loop on address range
2082mtest	- simple RAM test
2083icache	- enable or disable instruction cache
2084dcache	- enable or disable data cache
2085reset	- Perform RESET of the CPU
2086echo	- echo args to console
2087version - print monitor version
2088help	- print online help
2089?	- alias for 'help'
2090
2091
2092Monitor Commands - Detailed Description:
2093========================================
2094
2095TODO.
2096
2097For now: just type "help <command>".
2098
2099
2100Environment Variables:
2101======================
2102
2103U-Boot supports user configuration using Environment Variables which
2104can be made persistent by saving to Flash memory.
2105
2106Environment Variables are set using "setenv", printed using
2107"printenv", and saved to Flash using "saveenv". Using "setenv"
2108without a value can be used to delete a variable from the
2109environment. As long as you don't save the environment you are
2110working with an in-memory copy. In case the Flash area containing the
2111environment is erased by accident, a default environment is provided.
2112
2113Some configuration options can be set using Environment Variables:
2114
2115  baudrate	- see CONFIG_BAUDRATE
2116
2117  bootdelay	- see CONFIG_BOOTDELAY
2118
2119  bootcmd	- see CONFIG_BOOTCOMMAND
2120
2121  bootargs	- Boot arguments when booting an RTOS image
2122
2123  bootfile	- Name of the image to load with TFTP
2124
2125  autoload	- if set to "no" (any string beginning with 'n'),
2126		  "bootp" will just load perform a lookup of the
2127		  configuration from the BOOTP server, but not try to
2128		  load any image using TFTP
2129
2130  autostart	- if set to "yes", an image loaded using the "bootp",
2131		  "rarpboot", "tftpboot" or "diskboot" commands will
2132		  be automatically started (by internally calling
2133		  "bootm")
2134
2135		  If set to "no", a standalone image passed to the
2136		  "bootm" command will be copied to the load address
2137		  (and eventually uncompressed), but NOT be started.
2138		  This can be used to load and uncompress arbitrary
2139		  data.
2140
2141  initrd_high	- restrict positioning of initrd images:
2142		  If this variable is not set, initrd images will be
2143		  copied to the highest possible address in RAM; this
2144		  is usually what you want since it allows for
2145		  maximum initrd size. If for some reason you want to
2146		  make sure that the initrd image is loaded below the
2147		  CFG_BOOTMAPSZ limit, you can set this environment
2148		  variable to a value of "no" or "off" or "0".
2149		  Alternatively, you can set it to a maximum upper
2150		  address to use (U-Boot will still check that it
2151		  does not overwrite the U-Boot stack and data).
2152
2153		  For instance, when you have a system with 16 MB
2154		  RAM, and want to reserve 4 MB from use by Linux,
2155		  you can do this by adding "mem=12M" to the value of
2156		  the "bootargs" variable. However, now you must make
2157		  sure that the initrd image is placed in the first
2158		  12 MB as well - this can be done with
2159
2160		  setenv initrd_high 00c00000
2161
2162		  If you set initrd_high to 0xFFFFFFFF, this is an
2163		  indication to U-Boot that all addresses are legal
2164		  for the Linux kernel, including addresses in flash
2165		  memory. In this case U-Boot will NOT COPY the
2166		  ramdisk at all. This may be useful to reduce the
2167		  boot time on your system, but requires that this
2168		  feature is supported by your Linux kernel.
2169
2170  ipaddr	- IP address; needed for tftpboot command
2171
2172  loadaddr	- Default load address for commands like "bootp",
2173		  "rarpboot", "tftpboot", "loadb" or "diskboot"
2174
2175  loads_echo	- see CONFIG_LOADS_ECHO
2176
2177  serverip	- TFTP server IP address; needed for tftpboot command
2178
2179  bootretry	- see CONFIG_BOOT_RETRY_TIME
2180
2181  bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR
2182
2183  bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR
2184
2185
2186The following environment variables may be used and automatically
2187updated by the network boot commands ("bootp" and "rarpboot"),
2188depending the information provided by your boot server:
2189
2190  bootfile	- see above
2191  dnsip		- IP address of your Domain Name Server
2192  dnsip2	- IP address of your secondary Domain Name Server
2193  gatewayip	- IP address of the Gateway (Router) to use
2194  hostname	- Target hostname
2195  ipaddr	- see above
2196  netmask	- Subnet Mask
2197  rootpath	- Pathname of the root filesystem on the NFS server
2198  serverip	- see above
2199
2200
2201There are two special Environment Variables:
2202
2203  serial#	- contains hardware identification information such
2204		  as type string and/or serial number
2205  ethaddr	- Ethernet address
2206
2207These variables can be set only once (usually during manufacturing of
2208the board). U-Boot refuses to delete or overwrite these variables
2209once they have been set once.
2210
2211
2212Further special Environment Variables:
2213
2214  ver		- Contains the U-Boot version string as printed
2215		  with the "version" command. This variable is
2216		  readonly (see CONFIG_VERSION_VARIABLE).
2217
2218
2219Please note that changes to some configuration parameters may take
2220only effect after the next boot (yes, that's just like Windoze :-).
2221
2222
2223Command Line Parsing:
2224=====================
2225
2226There are two different command line parsers available with U-Boot:
2227the old "simple" one, and the much more powerful "hush" shell:
2228
2229Old, simple command line parser:
2230--------------------------------
2231
2232- supports environment variables (through setenv / saveenv commands)
2233- several commands on one line, separated by ';'
2234- variable substitution using "... $(name) ..." syntax
2235- special characters ('$', ';') can be escaped by prefixing with '\',
2236  for example:
2237	setenv bootcmd bootm \$(address)
2238- You can also escape text by enclosing in single apostrophes, for example:
2239	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2240
2241Hush shell:
2242-----------
2243
2244- similar to Bourne shell, with control structures like
2245  if...then...else...fi, for...do...done; while...do...done,
2246  until...do...done, ...
2247- supports environment ("global") variables (through setenv / saveenv
2248  commands) and local shell variables (through standard shell syntax
2249  "name=value"); only environment variables can be used with "run"
2250  command
2251
2252General rules:
2253--------------
2254
2255(1) If a command line (or an environment variable executed by a "run"
2256    command) contains several commands separated by semicolon, and
2257    one of these commands fails, then the remaining commands will be
2258    executed anyway.
2259
2260(2) If you execute several variables with one call to run (i. e.
2261    calling run with a list af variables as arguments), any failing
2262    command will cause "run" to terminate, i. e. the remaining
2263    variables are not executed.
2264
2265Note for Redundant Ethernet Interfaces:
2266=======================================
2267
2268Some boards come with redundant ethernet interfaces; U-Boot supports
2269such configurations and is capable of automatic selection of a
2270"working" interface when needed. MAC assignment works as follows:
2271
2272Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2273MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2274"eth1addr" (=>eth1), "eth2addr", ...
2275
2276If the network interface stores some valid MAC address (for instance
2277in SROM), this is used as default address if there is NO correspon-
2278ding setting in the environment; if the corresponding environment
2279variable is set, this overrides the settings in the card; that means:
2280
2281o If the SROM has a valid MAC address, and there is no address in the
2282  environment, the SROM's address is used.
2283
2284o If there is no valid address in the SROM, and a definition in the
2285  environment exists, then the value from the environment variable is
2286  used.
2287
2288o If both the SROM and the environment contain a MAC address, and
2289  both addresses are the same, this MAC address is used.
2290
2291o If both the SROM and the environment contain a MAC address, and the
2292  addresses differ, the value from the environment is used and a
2293  warning is printed.
2294
2295o If neither SROM nor the environment contain a MAC address, an error
2296  is raised.
2297
2298
2299Image Formats:
2300==============
2301
2302The "boot" commands of this monitor operate on "image" files which
2303can be basicly anything, preceeded by a special header; see the
2304definitions in include/image.h for details; basicly, the header
2305defines the following image properties:
2306
2307* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2308  4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2309  LynxOS, pSOS, QNX, RTEMS, ARTOS;
2310  Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2311* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2312  IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2313  Currently supported: PowerPC).
2314* Compression Type (uncompressed, gzip, bzip2)
2315* Load Address
2316* Entry Point
2317* Image Name
2318* Image Timestamp
2319
2320The header is marked by a special Magic Number, and both the header
2321and the data portions of the image are secured against corruption by
2322CRC32 checksums.
2323
2324
2325Linux Support:
2326==============
2327
2328Although U-Boot should support any OS or standalone application
2329easily, the main focus has always been on Linux during the design of
2330U-Boot.
2331
2332U-Boot includes many features that so far have been part of some
2333special "boot loader" code within the Linux kernel. Also, any
2334"initrd" images to be used are no longer part of one big Linux image;
2335instead, kernel and "initrd" are separate images. This implementation
2336serves several purposes:
2337
2338- the same features can be used for other OS or standalone
2339  applications (for instance: using compressed images to reduce the
2340  Flash memory footprint)
2341
2342- it becomes much easier to port new Linux kernel versions because
2343  lots of low-level, hardware dependent stuff are done by U-Boot
2344
2345- the same Linux kernel image can now be used with different "initrd"
2346  images; of course this also means that different kernel images can
2347  be run with the same "initrd". This makes testing easier (you don't
2348  have to build a new "zImage.initrd" Linux image when you just
2349  change a file in your "initrd"). Also, a field-upgrade of the
2350  software is easier now.
2351
2352
2353Linux HOWTO:
2354============
2355
2356Porting Linux to U-Boot based systems:
2357---------------------------------------
2358
2359U-Boot cannot save you from doing all the necessary modifications to
2360configure the Linux device drivers for use with your target hardware
2361(no, we don't intend to provide a full virtual machine interface to
2362Linux :-).
2363
2364But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2365
2366Just make sure your machine specific header file (for instance
2367include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2368Information structure as we define in include/u-boot.h, and make
2369sure that your definition of IMAP_ADDR uses the same value as your
2370U-Boot configuration in CFG_IMMR.
2371
2372
2373Configuring the Linux kernel:
2374-----------------------------
2375
2376No specific requirements for U-Boot. Make sure you have some root
2377device (initial ramdisk, NFS) for your target system.
2378
2379
2380Building a Linux Image:
2381-----------------------
2382
2383With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2384not used. If you use recent kernel source, a new build target
2385"uImage" will exist which automatically builds an image usable by
2386U-Boot. Most older kernels also have support for a "pImage" target,
2387which was introduced for our predecessor project PPCBoot and uses a
2388100% compatible format.
2389
2390Example:
2391
2392	make TQM850L_config
2393	make oldconfig
2394	make dep
2395	make uImage
2396
2397The "uImage" build target uses a special tool (in 'tools/mkimage') to
2398encapsulate a compressed Linux kernel image with header  information,
2399CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2400
2401* build a standard "vmlinux" kernel image (in ELF binary format):
2402
2403* convert the kernel into a raw binary image:
2404
2405	${CROSS_COMPILE}-objcopy -O binary \
2406				 -R .note -R .comment \
2407				 -S vmlinux linux.bin
2408
2409* compress the binary image:
2410
2411	gzip -9 linux.bin
2412
2413* package compressed binary image for U-Boot:
2414
2415	mkimage -A ppc -O linux -T kernel -C gzip \
2416		-a 0 -e 0 -n "Linux Kernel Image" \
2417		-d linux.bin.gz uImage
2418
2419
2420The "mkimage" tool can also be used to create ramdisk images for use
2421with U-Boot, either separated from the Linux kernel image, or
2422combined into one file. "mkimage" encapsulates the images with a 64
2423byte header containing information about target architecture,
2424operating system, image type, compression method, entry points, time
2425stamp, CRC32 checksums, etc.
2426
2427"mkimage" can be called in two ways: to verify existing images and
2428print the header information, or to build new images.
2429
2430In the first form (with "-l" option) mkimage lists the information
2431contained in the header of an existing U-Boot image; this includes
2432checksum verification:
2433
2434	tools/mkimage -l image
2435	  -l ==> list image header information
2436
2437The second form (with "-d" option) is used to build a U-Boot image
2438from a "data file" which is used as image payload:
2439
2440	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2441		      -n name -d data_file image
2442	  -A ==> set architecture to 'arch'
2443	  -O ==> set operating system to 'os'
2444	  -T ==> set image type to 'type'
2445	  -C ==> set compression type 'comp'
2446	  -a ==> set load address to 'addr' (hex)
2447	  -e ==> set entry point to 'ep' (hex)
2448	  -n ==> set image name to 'name'
2449	  -d ==> use image data from 'datafile'
2450
2451Right now, all Linux kernels use the same load address	(0x00000000),
2452but the entry point address depends on the kernel version:
2453
2454- 2.2.x kernels have the entry point at 0x0000000C,
2455- 2.3.x and later kernels have the entry point at 0x00000000.
2456
2457So a typical call to build a U-Boot image would read:
2458
2459	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2460	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2461	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2462	> examples/uImage.TQM850L
2463	Image Name:   2.4.4 kernel for TQM850L
2464	Created:      Wed Jul 19 02:34:59 2000
2465	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
2466	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
2467	Load Address: 0x00000000
2468	Entry Point:  0x00000000
2469
2470To verify the contents of the image (or check for corruption):
2471
2472	-> tools/mkimage -l examples/uImage.TQM850L
2473	Image Name:   2.4.4 kernel for TQM850L
2474	Created:      Wed Jul 19 02:34:59 2000
2475	Image Type:   PowerPC Linux Kernel Image (gzip compressed)
2476	Data Size:    335725 Bytes = 327.86 kB = 0.32 MB
2477	Load Address: 0x00000000
2478	Entry Point:  0x00000000
2479
2480NOTE: for embedded systems where boot time is critical you can trade
2481speed for memory and install an UNCOMPRESSED image instead: this
2482needs more space in Flash, but boots much faster since it does not
2483need to be uncompressed:
2484
2485	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2486	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2487	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2488	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2489	> examples/uImage.TQM850L-uncompressed
2490	Image Name:   2.4.4 kernel for TQM850L
2491	Created:      Wed Jul 19 02:34:59 2000
2492	Image Type:   PowerPC Linux Kernel Image (uncompressed)
2493	Data Size:    792160 Bytes = 773.59 kB = 0.76 MB
2494	Load Address: 0x00000000
2495	Entry Point:  0x00000000
2496
2497
2498Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2499when your kernel is intended to use an initial ramdisk:
2500
2501	-> tools/mkimage -n 'Simple Ramdisk Image' \
2502	> -A ppc -O linux -T ramdisk -C gzip \
2503	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2504	Image Name:   Simple Ramdisk Image
2505	Created:      Wed Jan 12 14:01:50 2000
2506	Image Type:   PowerPC Linux RAMDisk Image (gzip compressed)
2507	Data Size:    566530 Bytes = 553.25 kB = 0.54 MB
2508	Load Address: 0x00000000
2509	Entry Point:  0x00000000
2510
2511
2512Installing a Linux Image:
2513-------------------------
2514
2515To downloading a U-Boot image over the serial (console) interface,
2516you must convert the image to S-Record format:
2517
2518	objcopy -I binary -O srec examples/image examples/image.srec
2519
2520The 'objcopy' does not understand the information in the U-Boot
2521image header, so the resulting S-Record file will be relative to
2522address 0x00000000. To load it to a given address, you need to
2523specify the target address as 'offset' parameter with the 'loads'
2524command.
2525
2526Example: install the image to address 0x40100000 (which on the
2527TQM8xxL is in the first Flash bank):
2528
2529	=> erase 40100000 401FFFFF
2530
2531	.......... done
2532	Erased 8 sectors
2533
2534	=> loads 40100000
2535	## Ready for S-Record download ...
2536	~>examples/image.srec
2537	1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2538	...
2539	15989 15990 15991 15992
2540	[file transfer complete]
2541	[connected]
2542	## Start Addr = 0x00000000
2543
2544
2545You can check the success of the download using the 'iminfo' command;
2546this includes a checksum verification so you  can  be  sure  no	 data
2547corruption happened:
2548
2549	=> imi 40100000
2550
2551	## Checking Image at 40100000 ...
2552	   Image Name:	 2.2.13 for initrd on TQM850L
2553	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2554	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2555	   Load Address: 00000000
2556	   Entry Point:	 0000000c
2557	   Verifying Checksum ... OK
2558
2559
2560Boot Linux:
2561-----------
2562
2563The "bootm" command is used to boot an application that is stored in
2564memory (RAM or Flash). In case of a Linux kernel image, the contents
2565of the "bootargs" environment variable is passed to the kernel as
2566parameters. You can check and modify this variable using the
2567"printenv" and "setenv" commands:
2568
2569
2570	=> printenv bootargs
2571	bootargs=root=/dev/ram
2572
2573	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2574
2575	=> printenv bootargs
2576	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2577
2578	=> bootm 40020000
2579	## Booting Linux kernel at 40020000 ...
2580	   Image Name:	 2.2.13 for NFS on TQM850L
2581	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2582	   Data Size:	 381681 Bytes = 372 kB = 0 MB
2583	   Load Address: 00000000
2584	   Entry Point:	 0000000c
2585	   Verifying Checksum ... OK
2586	   Uncompressing Kernel Image ... OK
2587	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
2588	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2589	time_init: decrementer frequency = 187500000/60
2590	Calibrating delay loop... 49.77 BogoMIPS
2591	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2592	...
2593
2594If you want to boot a Linux kernel with initial ram disk, you pass
2595the memory addresses of both the kernel and the initrd image (PPBCOOT
2596format!) to the "bootm" command:
2597
2598	=> imi 40100000 40200000
2599
2600	## Checking Image at 40100000 ...
2601	   Image Name:	 2.2.13 for initrd on TQM850L
2602	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2603	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2604	   Load Address: 00000000
2605	   Entry Point:	 0000000c
2606	   Verifying Checksum ... OK
2607
2608	## Checking Image at 40200000 ...
2609	   Image Name:	 Simple Ramdisk Image
2610	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
2611	   Data Size:	 566530 Bytes = 553 kB = 0 MB
2612	   Load Address: 00000000
2613	   Entry Point:	 00000000
2614	   Verifying Checksum ... OK
2615
2616	=> bootm 40100000 40200000
2617	## Booting Linux kernel at 40100000 ...
2618	   Image Name:	 2.2.13 for initrd on TQM850L
2619	   Image Type:	 PowerPC Linux Kernel Image (gzip compressed)
2620	   Data Size:	 335725 Bytes = 327 kB = 0 MB
2621	   Load Address: 00000000
2622	   Entry Point:	 0000000c
2623	   Verifying Checksum ... OK
2624	   Uncompressing Kernel Image ... OK
2625	## Loading RAMDisk Image at 40200000 ...
2626	   Image Name:	 Simple Ramdisk Image
2627	   Image Type:	 PowerPC Linux RAMDisk Image (gzip compressed)
2628	   Data Size:	 566530 Bytes = 553 kB = 0 MB
2629	   Load Address: 00000000
2630	   Entry Point:	 00000000
2631	   Verifying Checksum ... OK
2632	   Loading Ramdisk ... OK
2633	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
2634	Boot arguments: root=/dev/ram
2635	time_init: decrementer frequency = 187500000/60
2636	Calibrating delay loop... 49.77 BogoMIPS
2637	...
2638	RAMDISK: Compressed image found at block 0
2639	VFS: Mounted root (ext2 filesystem).
2640
2641	bash#
2642
2643More About U-Boot Image Types:
2644------------------------------
2645
2646U-Boot supports the following image types:
2647
2648   "Standalone Programs" are directly runnable in the environment
2649	provided by U-Boot; it is expected that (if they behave
2650	well) you can continue to work in U-Boot after return from
2651	the Standalone Program.
2652   "OS Kernel Images" are usually images of some Embedded OS which
2653	will take over control completely. Usually these programs
2654	will install their own set of exception handlers, device
2655	drivers, set up the MMU, etc. - this means, that you cannot
2656	expect to re-enter U-Boot except by resetting the CPU.
2657   "RAMDisk Images" are more or less just data blocks, and their
2658	parameters (address, size) are passed to an OS kernel that is
2659	being started.
2660   "Multi-File Images" contain several images, typically an OS
2661	(Linux) kernel image and one or more data images like
2662	RAMDisks. This construct is useful for instance when you want
2663	to boot over the network using BOOTP etc., where the boot
2664	server provides just a single image file, but you want to get
2665	for instance an OS kernel and a RAMDisk image.
2666
2667	"Multi-File Images" start with a list of image sizes, each
2668	image size (in bytes) specified by an "uint32_t" in network
2669	byte order. This list is terminated by an "(uint32_t)0".
2670	Immediately after the terminating 0 follow the images, one by
2671	one, all aligned on "uint32_t" boundaries (size rounded up to
2672	a multiple of 4 bytes).
2673
2674   "Firmware Images" are binary images containing firmware (like
2675	U-Boot or FPGA images) which usually will be programmed to
2676	flash memory.
2677
2678   "Script files" are command sequences that will be executed by
2679	U-Boot's command interpreter; this feature is especially
2680	useful when you configure U-Boot to use a real shell (hush)
2681	as command interpreter.
2682
2683
2684Standalone HOWTO:
2685=================
2686
2687One of the features of U-Boot is that you can dynamically load and
2688run "standalone" applications, which can use some resources of
2689U-Boot like console I/O functions or interrupt services.
2690
2691Two simple examples are included with the sources:
2692
2693"Hello World" Demo:
2694-------------------
2695
2696'examples/hello_world.c' contains a small "Hello World" Demo
2697application; it is automatically compiled when you build U-Boot.
2698It's configured to run at address 0x00040004, so you can play with it
2699like that:
2700
2701	=> loads
2702	## Ready for S-Record download ...
2703	~>examples/hello_world.srec
2704	1 2 3 4 5 6 7 8 9 10 11 ...
2705	[file transfer complete]
2706	[connected]
2707	## Start Addr = 0x00040004
2708
2709	=> go 40004 Hello World! This is a test.
2710	## Starting application at 0x00040004 ...
2711	Hello World
2712	argc = 7
2713	argv[0] = "40004"
2714	argv[1] = "Hello"
2715	argv[2] = "World!"
2716	argv[3] = "This"
2717	argv[4] = "is"
2718	argv[5] = "a"
2719	argv[6] = "test."
2720	argv[7] = "<NULL>"
2721	Hit any key to exit ...
2722
2723	## Application terminated, rc = 0x0
2724
2725Another example, which demonstrates how to register a CPM interrupt
2726handler with the U-Boot code, can be found in 'examples/timer.c'.
2727Here, a CPM timer is set up to generate an interrupt every second.
2728The interrupt service routine is trivial, just printing a '.'
2729character, but this is just a demo program. The application can be
2730controlled by the following keys:
2731
2732	? - print current values og the CPM Timer registers
2733	b - enable interrupts and start timer
2734	e - stop timer and disable interrupts
2735	q - quit application
2736
2737	=> loads
2738	## Ready for S-Record download ...
2739	~>examples/timer.srec
2740	1 2 3 4 5 6 7 8 9 10 11 ...
2741	[file transfer complete]
2742	[connected]
2743	## Start Addr = 0x00040004
2744
2745	=> go 40004
2746	## Starting application at 0x00040004 ...
2747	TIMERS=0xfff00980
2748	Using timer 1
2749	  tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2750
2751Hit 'b':
2752	[q, b, e, ?] Set interval 1000000 us
2753	Enabling timer
2754Hit '?':
2755	[q, b, e, ?] ........
2756	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2757Hit '?':
2758	[q, b, e, ?] .
2759	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2760Hit '?':
2761	[q, b, e, ?] .
2762	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2763Hit '?':
2764	[q, b, e, ?] .
2765	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2766Hit 'e':
2767	[q, b, e, ?] ...Stopping timer
2768Hit 'q':
2769	[q, b, e, ?] ## Application terminated, rc = 0x0
2770
2771
2772Minicom warning:
2773================
2774
2775Over time, many people have reported problems when trying to use the
2776"minicom" terminal emulation program for serial download. I (wd)
2777consider minicom to be broken, and recommend not to use it. Under
2778Unix, I recommend to use C-Kermit for general purpose use (and
2779especially for kermit binary protocol download ("loadb" command), and
2780use "cu" for S-Record download ("loads" command).
2781
2782Nevertheless, if you absolutely want to use it try adding this
2783configuration to your "File transfer protocols" section:
2784
2785	   Name    Program                      Name U/D FullScr IO-Red. Multi
2786	X  kermit  /usr/bin/kermit -i -l %l -s   Y    U    Y       N      N
2787	Y  kermit  /usr/bin/kermit -i -l %l -r   N    D    Y       N      N
2788
2789
2790NetBSD Notes:
2791=============
2792
2793Starting at version 0.9.2, U-Boot supports NetBSD both as host
2794(build U-Boot) and target system (boots NetBSD/mpc8xx).
2795
2796Building requires a cross environment; it is known to work on
2797NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2798need gmake since the Makefiles are not compatible with BSD make).
2799Note that the cross-powerpc package does not install include files;
2800attempting to build U-Boot will fail because <machine/ansi.h> is
2801missing.  This file has to be installed and patched manually:
2802
2803	# cd /usr/pkg/cross/powerpc-netbsd/include
2804	# mkdir powerpc
2805	# ln -s powerpc machine
2806	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2807	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST
2808
2809Native builds *don't* work due to incompatibilities between native
2810and U-Boot include files.
2811
2812Booting assumes that (the first part of) the image booted is a
2813stage-2 loader which in turn loads and then invokes the kernel
2814proper. Loader sources will eventually appear in the NetBSD source
2815tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2816meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2817details.
2818
2819
2820Implementation Internals:
2821=========================
2822
2823The following is not intended to be a complete description of every
2824implementation detail. However, it should help to understand the
2825inner workings of U-Boot and make it easier to port it to custom
2826hardware.
2827
2828
2829Initial Stack, Global Data:
2830---------------------------
2831
2832The implementation of U-Boot is complicated by the fact that U-Boot
2833starts running out of ROM (flash memory), usually without access to
2834system RAM (because the memory controller is not initialized yet).
2835This means that we don't have writable Data or BSS segments, and BSS
2836is not initialized as zero. To be able to get a C environment working
2837at all, we have to allocate at least a minimal stack. Implementation
2838options for this are defined and restricted by the CPU used: Some CPU
2839models provide on-chip memory (like the IMMR area on MPC8xx and
2840MPC826x processors), on others (parts of) the data cache can be
2841locked as (mis-) used as memory, etc.
2842
2843	Chris Hallinan posted a good summary of  these  issues  to  the
2844	u-boot-users mailing list:
2845
2846	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2847	From: "Chris Hallinan" <clh@net1plus.com>
2848	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2849	...
2850
2851	Correct me if I'm wrong, folks, but the way I understand it
2852	is this: Using DCACHE as initial RAM for Stack, etc, does not
2853	require any physical RAM backing up the cache. The cleverness
2854	is that the cache is being used as a temporary supply of
2855	necessary storage before the SDRAM controller is setup. It's
2856	beyond the scope of this list to expain the details, but you
2857	can see how this works by studying the cache architecture and
2858	operation in the architecture and processor-specific manuals.
2859
2860	OCM is On Chip Memory, which I believe the 405GP has 4K. It
2861	is another option for the system designer to use as an
2862	initial stack/ram area prior to SDRAM being available. Either
2863	option should work for you. Using CS 4 should be fine if your
2864	board designers haven't used it for something that would
2865	cause you grief during the initial boot! It is frequently not
2866	used.
2867
2868	CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2869	with your processor/board/system design. The default value
2870	you will find in any recent u-boot distribution in
2871	Walnut405.h should work for you. I'd set it to a value larger
2872	than your SDRAM module. If you have a 64MB SDRAM module, set
2873	it above 400_0000. Just make sure your board has no resources
2874	that are supposed to respond to that address! That code in
2875	start.S has been around a while and should work as is when
2876	you get the config right.
2877
2878	-Chris Hallinan
2879	DS4.COM, Inc.
2880
2881It is essential to remember this, since it has some impact on the C
2882code for the initialization procedures:
2883
2884* Initialized global data (data segment) is read-only. Do not attempt
2885  to write it.
2886
2887* Do not use any unitialized global data (or implicitely initialized
2888  as zero data - BSS segment) at all - this is undefined, initiali-
2889  zation is performed later (when relocating to RAM).
2890
2891* Stack space is very limited. Avoid big data buffers or things like
2892  that.
2893
2894Having only the stack as writable memory limits means we cannot use
2895normal global data to share information beween the code. But it
2896turned out that the implementation of U-Boot can be greatly
2897simplified by making a global data structure (gd_t) available to all
2898functions. We could pass a pointer to this data as argument to _all_
2899functions, but this would bloat the code. Instead we use a feature of
2900the GCC compiler (Global Register Variables) to share the data: we
2901place a pointer (gd) to the global data into a register which we
2902reserve for this purpose.
2903
2904When choosing a register for such a purpose we are restricted by the
2905relevant  (E)ABI  specifications for the current architecture, and by
2906GCC's implementation.
2907
2908For PowerPC, the following registers have specific use:
2909	R1:	stack pointer
2910	R2:	TOC pointer
2911	R3-R4:	parameter passing and return values
2912	R5-R10:	parameter passing
2913	R13:	small data area pointer
2914	R30:	GOT pointer
2915	R31:	frame pointer
2916
2917	(U-Boot also uses R14 as internal GOT pointer.)
2918
2919    ==> U-Boot will use R29 to hold a pointer to the global data
2920
2921    Note: on PPC, we could use a static initializer (since the
2922    address of the global data structure is known at compile time),
2923    but it turned out that reserving a register results in somewhat
2924    smaller code - although the code savings are not that big (on
2925    average for all boards 752 bytes for the whole U-Boot image,
2926    624 text + 127 data).
2927
2928On ARM, the following registers are used:
2929
2930	R0:	function argument word/integer result
2931	R1-R3:	function argument word
2932	R9:	GOT pointer
2933	R10:	stack limit (used only if stack checking if enabled)
2934	R11:	argument (frame) pointer
2935	R12:	temporary workspace
2936	R13:	stack pointer
2937	R14:	link register
2938	R15:	program counter
2939
2940    ==> U-Boot will use R8 to hold a pointer to the global data
2941
2942
2943Memory Management:
2944------------------
2945
2946U-Boot runs in system state and uses physical addresses, i.e. the
2947MMU is not used either for address mapping nor for memory protection.
2948
2949The available memory is mapped to fixed addresses using the memory
2950controller. In this process, a contiguous block is formed for each
2951memory type (Flash, SDRAM, SRAM), even when it consists of several
2952physical memory banks.
2953
2954U-Boot is installed in the first 128 kB of the first Flash bank (on
2955TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2956booting and sizing and initializing DRAM, the code relocates itself
2957to the upper end of DRAM. Immediately below the U-Boot code some
2958memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2959configuration setting]. Below that, a structure with global Board
2960Info data is placed, followed by the stack (growing downward).
2961
2962Additionally, some exception handler code is copied to the low 8 kB
2963of DRAM (0x00000000 ... 0x00001FFF).
2964
2965So a typical memory configuration with 16 MB of DRAM could look like
2966this:
2967
2968	0x0000 0000	Exception Vector code
2969	      :
2970	0x0000 1FFF
2971	0x0000 2000	Free for Application Use
2972	      :
2973	      :
2974
2975	      :
2976	      :
2977	0x00FB FF20	Monitor Stack (Growing downward)
2978	0x00FB FFAC	Board Info Data and permanent copy of global data
2979	0x00FC 0000	Malloc Arena
2980	      :
2981	0x00FD FFFF
2982	0x00FE 0000	RAM Copy of Monitor Code
2983	...		eventually: LCD or video framebuffer
2984	...		eventually: pRAM (Protected RAM - unchanged by reset)
2985	0x00FF FFFF	[End of RAM]
2986
2987
2988System Initialization:
2989----------------------
2990
2991In the reset configuration, U-Boot starts at the reset entry point
2992(on most PowerPC systens at address 0x00000100). Because of the reset
2993configuration for CS0# this is a mirror of the onboard Flash memory.
2994To be able to re-map memory U-Boot then jumps to its link address.
2995To be able to implement the initialization code in C, a (small!)
2996initial stack is set up in the internal Dual Ported RAM (in case CPUs
2997which provide such a feature like MPC8xx or MPC8260), or in a locked
2998part of the data cache. After that, U-Boot initializes the CPU core,
2999the caches and the SIU.
3000
3001Next, all (potentially) available memory banks are mapped using a
3002preliminary mapping. For example, we put them on 512 MB boundaries
3003(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3004on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3005programmed for SDRAM access. Using the temporary configuration, a
3006simple memory test is run that determines the size of the SDRAM
3007banks.
3008
3009When there is more than one SDRAM bank, and the banks are of
3010different size, the largest is mapped first. For equal size, the first
3011bank (CS2#) is mapped first. The first mapping is always for address
30120x00000000, with any additional banks following immediately to create
3013contiguous memory starting from 0.
3014
3015Then, the monitor installs itself at the upper end of the SDRAM area
3016and allocates memory for use by malloc() and for the global Board
3017Info data; also, the exception vector code is copied to the low RAM
3018pages, and the final stack is set up.
3019
3020Only after this relocation will you have a "normal" C environment;
3021until that you are restricted in several ways, mostly because you are
3022running from ROM, and because the code will have to be relocated to a
3023new address in RAM.
3024
3025
3026U-Boot Porting Guide:
3027----------------------
3028
3029[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3030list, October 2002]
3031
3032
3033int main (int argc, char *argv[])
3034{
3035	sighandler_t no_more_time;
3036
3037	signal (SIGALRM, no_more_time);
3038	alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3039
3040	if (available_money > available_manpower) {
3041		pay consultant to port U-Boot;
3042		return 0;
3043	}
3044
3045	Download latest U-Boot source;
3046
3047	Subscribe to u-boot-users mailing list;
3048
3049	if (clueless) {
3050		email ("Hi, I am new to U-Boot, how do I get started?");
3051	}
3052
3053	while (learning) {
3054		Read the README file in the top level directory;
3055		Read http://www.denx.de/re/DPLG.html
3056		Read the source, Luke;
3057	}
3058
3059	if (available_money > toLocalCurrency ($2500)) {
3060		Buy a BDI2000;
3061	} else {
3062		Add a lot of aggravation and time;
3063	}
3064
3065	Create your own board support subdirectory;
3066
3067	Create your own board config file;
3068
3069	while (!running) {
3070		do {
3071			Add / modify source code;
3072		} until (compiles);
3073		Debug;
3074		if (clueless)
3075			email ("Hi, I am having problems...");
3076	}
3077	Send patch file to Wolfgang;
3078
3079	return 0;
3080}
3081
3082void no_more_time (int sig)
3083{
3084      hire_a_guru();
3085}
3086
3087
3088Coding Standards:
3089-----------------
3090
3091All contributions to U-Boot should conform to the Linux kernel
3092coding style; see the file "Documentation/CodingStyle" in your Linux
3093kernel source directory.
3094
3095Please note that U-Boot is implemented in C (and to some small parts
3096in Assembler); no C++ is used, so please do not use C++ style
3097comments (//) in your code.
3098
3099Submissions which do not conform to the standards may be returned
3100with a request to reformat the changes.
3101
3102
3103Submitting Patches:
3104-------------------
3105
3106Since the number of patches for U-Boot is growing, we need to
3107establish some rules. Submissions which do not conform to these rules
3108may be rejected, even when they contain important and valuable stuff.
3109
3110
3111When you send a patch, please include the following information with
3112it:
3113
3114* For bug fixes: a description of the bug and how your patch fixes
3115  this bug. Please try to include a way of demonstrating that the
3116  patch actually fixes something.
3117
3118* For new features: a description of the feature and your
3119  implementation.
3120
3121* A CHANGELOG entry as plaintext (separate from the patch)
3122
3123* For major contributions, your entry to the CREDITS file
3124
3125* When you add support for a new board, don't forget to add this
3126  board to the MAKEALL script, too.
3127
3128* If your patch adds new configuration options, don't forget to
3129  document these in the README file.
3130
3131* The patch itself. If you are accessing the CVS repository use "cvs
3132  update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3133  version of diff does not support these options, then get the latest
3134  version of GNU diff.
3135
3136  The current directory when running this command shall be the top
3137  level directory of the U-Boot source tree, or it's parent directory
3138  (i. e. please make sure that your patch includes sufficient
3139  directory information for the affected files).
3140
3141  We accept patches as plain text, MIME attachments or as uuencoded
3142  gzipped text.
3143
3144* If one logical set of modifications affects or creates several
3145  files, all these changes shall be submitted in a SINGLE patch file.
3146
3147* Changesets that contain different, unrelated modifications shall be
3148  submitted as SEPARATE patches, one patch per changeset.
3149
3150
3151Notes:
3152
3153* Before sending the patch, run the MAKEALL script on your patched
3154  source tree and make sure that no errors or warnings are reported
3155  for any of the boards.
3156
3157* Keep your modifications to the necessary minimum: A patch
3158  containing several unrelated changes or arbitrary reformats will be
3159  returned with a request to re-formatting / split it.
3160
3161* If you modify existing code, make sure that your new code does not
3162  add to the memory footprint of the code ;-) Small is beautiful!
3163  When adding new features, these should compile conditionally only
3164  (using #ifdef), and the resulting code with the new feature
3165  disabled must not need more memory than the old code without your
3166  modification.
3167