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wdenkc6097192002-11-03 00:24:07 +00001#
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
wdenk24ee89b2002-11-03 17:56:27 +000027This 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.
wdenkc6097192002-11-03 00:24:07 +000031
32The development of U-Boot is closely related to Linux: some parts of
wdenk24ee89b2002-11-03 17:56:27 +000033the source code originate in the Linux source tree, we have some
34header files in common, and special provision has been made to
wdenkc6097192002-11-03 00:24:07 +000035support 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
wdenk24ee89b2002-11-03 17:56:27 +000049Makefile have been tested to some extent and can be considered
wdenkc6097192002-11-03 00:24:07 +000050"working". In fact, many of them are used in production systems.
51
wdenk24ee89b2002-11-03 17:56:27 +000052In case of problems see the CHANGELOG and CREDITS files to find out
wdenkc6097192002-11-03 00:24:07 +000053who contributed the specific port.
54
wdenkc6097192002-11-03 00:24:07 +000055
56Where to get help:
57==================
58
wdenk24ee89b2002-11-03 17:56:27 +000059In 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
wdenkc6097192002-11-03 00:24:07 +000063before 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
wdenk24ee89b2002-11-03 17:56:27 +000071- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
wdenkc6097192002-11-03 00:24:07 +000072- 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
wdenk24ee89b2002-11-03 17:56:27 +000080- create ARMBoot project (http://sourceforge.net/projects/armboot)
wdenkc6097192002-11-03 00:24:07 +000081- add other CPU families (starting with ARM)
wdenk24ee89b2002-11-03 17:56:27 +000082- 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
wdenkc6097192002-11-03 00:24:07 +0000105
106
wdenk93f19cc2002-12-17 17:55:09 +0000107Versioning:
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
wdenkc6097192002-11-03 00:24:07 +0000119Directory Hierarchy:
120====================
121
122- board Board dependend files
123- common Misc architecture independend functions
124- cpu CPU specific files
125- disk Code for disk drive partition handling
126- doc Documentation (don't expect too much)
127- drivers Common used device drivers
128- dtt Digital Thermometer and Thermostat drivers
129- examples Example code for standalone applications, etc.
130- include Header Files
131- disk Harddisk interface code
132- net Networking code
133- ppc Files generic to PowerPC architecture
134- post Power On Self Test
135- post/arch Symlink to architecture specific Power On Self Test
136- post/arch-ppc PowerPC architecture specific Power On Self Test
137- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139- rtc Real Time Clock drivers
140- tools Tools to build S-Record or U-Boot images, etc.
141
142- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
wdenk0db5bca2003-03-31 17:27:09 +0000143- cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
wdenkc6097192002-11-03 00:24:07 +0000144- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
145- cpu/mpc824x Files specific to Motorola MPC824x CPUs
146- cpu/mpc8260 Files specific to Motorola MPC8260 CPU
147- cpu/ppc4xx Files specific to IBM 4xx CPUs
148
wdenk3bac3512003-03-12 10:41:04 +0000149- board/LEOX/ Files specific to boards manufactured by The LEOX team
150- board/LEOX/elpt860 Files specific to ELPT860 boards
wdenkc6097192002-11-03 00:24:07 +0000151- board/RPXClassic
152 Files specific to RPXClassic boards
153- board/RPXlite Files specific to RPXlite boards
wdenk2abbe072003-06-16 23:50:08 +0000154- board/at91rm9200dk Files specific to AT91RM9200DK boards
wdenkc6097192002-11-03 00:24:07 +0000155- board/c2mon Files specific to c2mon boards
wdenk0db5bca2003-03-31 17:27:09 +0000156- board/cmi Files specific to cmi boards
wdenkc6097192002-11-03 00:24:07 +0000157- board/cogent Files specific to Cogent boards
158 (need further configuration)
159 Files specific to CPCIISER4 boards
160- board/cpu86 Files specific to CPU86 boards
161- board/cray/ Files specific to boards manufactured by Cray
162- board/cray/L1 Files specific to L1 boards
163- board/cu824 Files specific to CU824 boards
164- board/ebony Files specific to IBM Ebony board
165- board/eric Files specific to ERIC boards
166- board/esd/ Files specific to boards manufactured by ESD
167- board/esd/adciop Files specific to ADCIOP boards
168- board/esd/ar405 Files specific to AR405 boards
169- board/esd/canbt Files specific to CANBT boards
170- board/esd/cpci405 Files specific to CPCI405 boards
171- board/esd/cpciiser4 Files specific to CPCIISER4 boards
172- board/esd/common Common files for ESD boards
173- board/esd/dasa_sim Files specific to DASA_SIM boards
174- board/esd/du405 Files specific to DU405 boards
175- board/esd/ocrtc Files specific to OCRTC boards
176- board/esd/pci405 Files specific to PCI405 boards
177- board/esteem192e
178 Files specific to ESTEEM192E boards
179- board/etx094 Files specific to ETX_094 boards
180- board/evb64260
181 Files specific to EVB64260 boards
182- board/fads Files specific to FADS boards
183- board/flagadm Files specific to FLAGADM boards
wdenk7aa78612003-05-03 15:50:43 +0000184- board/gen860t Files specific to GEN860T and GEN860T_SC boards
wdenkc6097192002-11-03 00:24:07 +0000185- board/genietv Files specific to GENIETV boards
186- board/gth Files specific to GTH boards
187- board/hermes Files specific to HERMES boards
188- board/hymod Files specific to HYMOD boards
189- board/icu862 Files specific to ICU862 boards
190- board/ip860 Files specific to IP860 boards
191- board/iphase4539
192 Files specific to Interphase4539 boards
193- board/ivm Files specific to IVMS8/IVML24 boards
194- board/lantec Files specific to LANTEC boards
195- board/lwmon Files specific to LWMON boards
196- board/mbx8xx Files specific to MBX boards
197- board/mpc8260ads
198 Files specific to MMPC8260ADS boards
199- board/mpl/ Files specific to boards manufactured by MPL
200- board/mpl/common Common files for MPL boards
201- board/mpl/pip405 Files specific to PIP405 boards
202- board/mpl/mip405 Files specific to MIP405 boards
203- board/musenki Files specific to MUSEKNI boards
204- board/mvs1 Files specific to MVS1 boards
205- board/nx823 Files specific to NX823 boards
206- board/oxc Files specific to OXC boards
207- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
208- board/pm826 Files specific to PM826 boards
209- board/ppmc8260
210 Files specific to PPMC8260 boards
211- board/rpxsuper
212 Files specific to RPXsuper boards
213- board/rsdproto
214 Files specific to RSDproto boards
215- board/sandpoint
216 Files specific to Sandpoint boards
217- board/sbc8260 Files specific to SBC8260 boards
218- board/sacsng Files specific to SACSng boards
219- board/siemens Files specific to boards manufactured by Siemens AG
220- board/siemens/CCM Files specific to CCM boards
221- board/siemens/IAD210 Files specific to IAD210 boards
222- board/siemens/SCM Files specific to SCM boards
223- board/siemens/pcu_e Files specific to PCU_E boards
224- board/sixnet Files specific to SIXNET boards
225- board/spd8xx Files specific to SPD8xxTS boards
226- board/tqm8260 Files specific to TQM8260 boards
227- board/tqm8xx Files specific to TQM8xxL boards
228- board/w7o Files specific to W7O boards
229- board/walnut405
230 Files specific to Walnut405 boards
231- board/westel/ Files specific to boards manufactured by Westel Wireless
232- board/westel/amx860 Files specific to AMX860 boards
233- board/utx8245 Files specific to UTX8245 boards
234
235Software Configuration:
236=======================
237
238Configuration is usually done using C preprocessor defines; the
239rationale behind that is to avoid dead code whenever possible.
240
241There are two classes of configuration variables:
242
243* Configuration _OPTIONS_:
244 These are selectable by the user and have names beginning with
245 "CONFIG_".
246
247* Configuration _SETTINGS_:
248 These depend on the hardware etc. and should not be meddled with if
249 you don't know what you're doing; they have names beginning with
250 "CFG_".
251
252Later we will add a configuration tool - probably similar to or even
253identical to what's used for the Linux kernel. Right now, we have to
254do the configuration by hand, which means creating some symbolic
255links and editing some configuration files. We use the TQM8xxL boards
256as an example here.
257
258
259Selection of Processor Architecture and Board Type:
260---------------------------------------------------
261
262For all supported boards there are ready-to-use default
263configurations available; just type "make <board_name>_config".
264
265Example: For a TQM823L module type:
266
267 cd u-boot
268 make TQM823L_config
269
270For the Cogent platform, you need to specify the cpu type as well;
271e.g. "make cogent_mpc8xx_config". And also configure the cogent
272directory according to the instructions in cogent/README.
273
274
275Configuration Options:
276----------------------
277
278Configuration depends on the combination of board and CPU type; all
279such information is kept in a configuration file
280"include/configs/<board_name>.h".
281
282Example: For a TQM823L module, all configuration settings are in
283"include/configs/TQM823L.h".
284
285
wdenk7f6c2cb2002-11-10 22:06:23 +0000286Many of the options are named exactly as the corresponding Linux
287kernel configuration options. The intention is to make it easier to
288build a config tool - later.
289
290
wdenkc6097192002-11-03 00:24:07 +0000291The following options need to be configured:
292
293- CPU Type: Define exactly one of
294
295 PowerPC based CPUs:
296 -------------------
297 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
wdenk0db5bca2003-03-31 17:27:09 +0000298 or CONFIG_MPC5xx
wdenkc6097192002-11-03 00:24:07 +0000299 or CONFIG_MPC824X, CONFIG_MPC8260
300 or CONFIG_IOP480
301 or CONFIG_405GP
302 or CONFIG_440
303 or CONFIG_MPC74xx
304
305 ARM based CPUs:
306 ---------------
307 CONFIG_SA1110
308 CONFIG_ARM7
309 CONFIG_PXA250
310
311
312- Board Type: Define exactly one of
313
314 PowerPC based boards:
315 ---------------------
316
317 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
318 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
319 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
320 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
321 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
322 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
323 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
324 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
325 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
326 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
327 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
328 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
329 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
330 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
331 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
332 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
333 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
334 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
335 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
336 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
337 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
338 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
339 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
340 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
341 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
342 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
343 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
344 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
345 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
wdenk608c9142003-01-13 23:54:46 +0000346 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
wdenk7f70e852003-05-20 14:25:27 +0000347 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
wdenk682011f2003-06-03 23:54:09 +0000348 CONFIG_NETVIA, CONFIG_RBC823
wdenkc6097192002-11-03 00:24:07 +0000349
350 ARM based boards:
351 -----------------
352
353 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
354 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
355 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
wdenk2abbe072003-06-16 23:50:08 +0000356 CONFIG_TRAB, CONFIG_AT91RM9200DK
wdenkc6097192002-11-03 00:24:07 +0000357
358
359- CPU Module Type: (if CONFIG_COGENT is defined)
360 Define exactly one of
361 CONFIG_CMA286_60_OLD
362--- FIXME --- not tested yet:
363 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
364 CONFIG_CMA287_23, CONFIG_CMA287_50
365
366- Motherboard Type: (if CONFIG_COGENT is defined)
367 Define exactly one of
368 CONFIG_CMA101, CONFIG_CMA102
369
370- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
371 Define one or more of
372 CONFIG_CMA302
373
374- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
375 Define one or more of
376 CONFIG_LCD_HEARTBEAT - update a character position on
377 the lcd display every second with
378 a "rotator" |\-/|\-/
379
380- MPC824X Family Member (if CONFIG_MPC824X is defined)
381 Define exactly one of
382 CONFIG_MPC8240, CONFIG_MPC8245
383
384- 8xx CPU Options: (if using an 8xx cpu)
385 Define one or more of
386 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
387 no 32KHz reference PIT/RTC clock
388
389- Clock Interface:
390 CONFIG_CLOCKS_IN_MHZ
391
392 U-Boot stores all clock information in Hz
393 internally. For binary compatibility with older Linux
394 kernels (which expect the clocks passed in the
395 bd_info data to be in MHz) the environment variable
396 "clocks_in_mhz" can be defined so that U-Boot
397 converts clock data to MHZ before passing it to the
398 Linux kernel.
399
400 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
401 "clocks_in_mhz=1" is automatically included in the
402 default environment.
403
404- Console Interface:
wdenk43d96162003-03-06 00:02:04 +0000405 Depending on board, define exactly one serial port
406 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
407 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
408 console by defining CONFIG_8xx_CONS_NONE
wdenkc6097192002-11-03 00:24:07 +0000409
410 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
411 port routines must be defined elsewhere
412 (i.e. serial_init(), serial_getc(), ...)
413
414 CONFIG_CFB_CONSOLE
415 Enables console device for a color framebuffer. Needs following
416 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
417 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
418 (default big endian)
419 VIDEO_HW_RECTFILL graphic chip supports
420 rectangle fill
421 (cf. smiLynxEM)
422 VIDEO_HW_BITBLT graphic chip supports
423 bit-blit (cf. smiLynxEM)
424 VIDEO_VISIBLE_COLS visible pixel columns
425 (cols=pitch)
426 VIDEO_VISIBLE_ROWS visible pixel rows
427 VIDEO_PIXEL_SIZE bytes per pixel
428 VIDEO_DATA_FORMAT graphic data format
429 (0-5, cf. cfb_console.c)
430 VIDEO_FB_ADRS framebuffer address
431 VIDEO_KBD_INIT_FCT keyboard int fct
432 (i.e. i8042_kbd_init())
433 VIDEO_TSTC_FCT test char fct
434 (i.e. i8042_tstc)
435 VIDEO_GETC_FCT get char fct
436 (i.e. i8042_getc)
437 CONFIG_CONSOLE_CURSOR cursor drawing on/off
438 (requires blink timer
439 cf. i8042.c)
440 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
441 CONFIG_CONSOLE_TIME display time/date info in
442 upper right corner
443 (requires CFG_CMD_DATE)
444 CONFIG_VIDEO_LOGO display Linux logo in
445 upper left corner
wdenka6c7ad22002-12-03 21:28:10 +0000446 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
447 linux_logo.h for logo.
448 Requires CONFIG_VIDEO_LOGO
wdenkc6097192002-11-03 00:24:07 +0000449 CONFIG_CONSOLE_EXTRA_INFO
450 addional board info beside
451 the logo
452
wdenk43d96162003-03-06 00:02:04 +0000453 When CONFIG_CFB_CONSOLE is defined, video console is
454 default i/o. Serial console can be forced with
455 environment 'console=serial'.
wdenkc6097192002-11-03 00:24:07 +0000456
457- Console Baudrate:
458 CONFIG_BAUDRATE - in bps
459 Select one of the baudrates listed in
460 CFG_BAUDRATE_TABLE, see below.
461
462- Interrupt driven serial port input:
463 CONFIG_SERIAL_SOFTWARE_FIFO
464
465 PPC405GP only.
466 Use an interrupt handler for receiving data on the
467 serial port. It also enables using hardware handshake
468 (RTS/CTS) and UART's built-in FIFO. Set the number of
469 bytes the interrupt driven input buffer should have.
470
471 Set to 0 to disable this feature (this is the default).
472 This will also disable hardware handshake.
473
stroese1d49b1f2003-05-23 11:39:05 +0000474- Console UART Number:
475 CONFIG_UART1_CONSOLE
476
477 IBM PPC4xx only.
478 If defined internal UART1 (and not UART0) is used
479 as default U-Boot console.
480
wdenkc6097192002-11-03 00:24:07 +0000481- Boot Delay: CONFIG_BOOTDELAY - in seconds
482 Delay before automatically booting the default image;
483 set to -1 to disable autoboot.
484
485 See doc/README.autoboot for these options that
486 work with CONFIG_BOOTDELAY. None are required.
487 CONFIG_BOOT_RETRY_TIME
488 CONFIG_BOOT_RETRY_MIN
489 CONFIG_AUTOBOOT_KEYED
490 CONFIG_AUTOBOOT_PROMPT
491 CONFIG_AUTOBOOT_DELAY_STR
492 CONFIG_AUTOBOOT_STOP_STR
493 CONFIG_AUTOBOOT_DELAY_STR2
494 CONFIG_AUTOBOOT_STOP_STR2
495 CONFIG_ZERO_BOOTDELAY_CHECK
496 CONFIG_RESET_TO_RETRY
497
498- Autoboot Command:
499 CONFIG_BOOTCOMMAND
500 Only needed when CONFIG_BOOTDELAY is enabled;
501 define a command string that is automatically executed
502 when no character is read on the console interface
503 within "Boot Delay" after reset.
504
505 CONFIG_BOOTARGS
wdenk43d96162003-03-06 00:02:04 +0000506 This can be used to pass arguments to the bootm
507 command. The value of CONFIG_BOOTARGS goes into the
508 environment value "bootargs".
wdenkc6097192002-11-03 00:24:07 +0000509
510 CONFIG_RAMBOOT and CONFIG_NFSBOOT
wdenk43d96162003-03-06 00:02:04 +0000511 The value of these goes into the environment as
512 "ramboot" and "nfsboot" respectively, and can be used
513 as a convenience, when switching between booting from
514 ram and nfs.
wdenkc6097192002-11-03 00:24:07 +0000515
516- Pre-Boot Commands:
517 CONFIG_PREBOOT
518
519 When this option is #defined, the existence of the
520 environment variable "preboot" will be checked
521 immediately before starting the CONFIG_BOOTDELAY
522 countdown and/or running the auto-boot command resp.
523 entering interactive mode.
524
525 This feature is especially useful when "preboot" is
526 automatically generated or modified. For an example
527 see the LWMON board specific code: here "preboot" is
528 modified when the user holds down a certain
529 combination of keys on the (special) keyboard when
530 booting the systems
531
532- Serial Download Echo Mode:
533 CONFIG_LOADS_ECHO
534 If defined to 1, all characters received during a
535 serial download (using the "loads" command) are
536 echoed back. This might be needed by some terminal
537 emulations (like "cu"), but may as well just take
538 time on others. This setting #define's the initial
539 value of the "loads_echo" environment variable.
540
541- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
542 CONFIG_KGDB_BAUDRATE
543 Select one of the baudrates listed in
544 CFG_BAUDRATE_TABLE, see below.
545
546- Monitor Functions:
547 CONFIG_COMMANDS
548 Most monitor functions can be selected (or
549 de-selected) by adjusting the definition of
550 CONFIG_COMMANDS; to select individual functions,
551 #define CONFIG_COMMANDS by "OR"ing any of the
552 following values:
553
554 #define enables commands:
555 -------------------------
556 CFG_CMD_ASKENV * ask for env variable
557 CFG_CMD_BDI bdinfo
558 CFG_CMD_BEDBUG Include BedBug Debugger
559 CFG_CMD_BOOTD bootd
560 CFG_CMD_CACHE icache, dcache
561 CFG_CMD_CONSOLE coninfo
562 CFG_CMD_DATE * support for RTC, date/time...
563 CFG_CMD_DHCP DHCP support
564 CFG_CMD_ECHO * echo arguments
565 CFG_CMD_EEPROM * EEPROM read/write support
566 CFG_CMD_ELF bootelf, bootvx
567 CFG_CMD_ENV saveenv
568 CFG_CMD_FDC * Floppy Disk Support
wdenk71f95112003-06-15 22:40:42 +0000569 CFG_CMD_FAT FAT partition support
wdenk2262cfe2002-11-18 00:14:45 +0000570 CFG_CMD_FDOS * Dos diskette Support
wdenkc6097192002-11-03 00:24:07 +0000571 CFG_CMD_FLASH flinfo, erase, protect
572 CFG_CMD_FPGA FPGA device initialization support
573 CFG_CMD_I2C * I2C serial bus support
574 CFG_CMD_IDE * IDE harddisk support
575 CFG_CMD_IMI iminfo
576 CFG_CMD_IMMAP * IMMR dump support
577 CFG_CMD_IRQ * irqinfo
578 CFG_CMD_KGDB * kgdb
579 CFG_CMD_LOADB loadb
580 CFG_CMD_LOADS loads
581 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
582 loop, mtest
wdenk71f95112003-06-15 22:40:42 +0000583 CFG_CMD_MMC MMC memory mapped support
wdenkc6097192002-11-03 00:24:07 +0000584 CFG_CMD_MII MII utility commands
585 CFG_CMD_NET bootp, tftpboot, rarpboot
586 CFG_CMD_PCI * pciinfo
587 CFG_CMD_PCMCIA * PCMCIA support
588 CFG_CMD_REGINFO * Register dump
589 CFG_CMD_RUN run command in env variable
590 CFG_CMD_SCSI * SCSI Support
591 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
592 CFG_CMD_SPI * SPI serial bus support
593 CFG_CMD_USB * USB support
594 CFG_CMD_BSP * Board SPecific functions
595 -----------------------------------------------
596 CFG_CMD_ALL all
597
598 CFG_CMD_DFL Default configuration; at the moment
599 this is includes all commands, except
600 the ones marked with "*" in the list
601 above.
602
603 If you don't define CONFIG_COMMANDS it defaults to
604 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
605 override the default settings in the respective
606 include file.
607
608 EXAMPLE: If you want all functions except of network
609 support you can write:
610
611 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
612
613
614 Note: Don't enable the "icache" and "dcache" commands
wdenk43d96162003-03-06 00:02:04 +0000615 (configuration option CFG_CMD_CACHE) unless you know
616 what you (and your U-Boot users) are doing. Data
617 cache cannot be enabled on systems like the 8xx or
618 8260 (where accesses to the IMMR region must be
619 uncached), and it cannot be disabled on all other
620 systems where we (mis-) use the data cache to hold an
621 initial stack and some data.
wdenkc6097192002-11-03 00:24:07 +0000622
623
624 XXX - this list needs to get updated!
625
626- Watchdog:
627 CONFIG_WATCHDOG
628 If this variable is defined, it enables watchdog
629 support. There must support in the platform specific
630 code for a watchdog. For the 8xx and 8260 CPUs, the
631 SIU Watchdog feature is enabled in the SYPCR
632 register.
633
stroesec1551ea2003-04-04 15:53:41 +0000634- U-Boot Version:
635 CONFIG_VERSION_VARIABLE
636 If this variable is defined, an environment variable
637 named "ver" is created by U-Boot showing the U-Boot
638 version as printed by the "version" command.
639 This variable is readonly.
640
wdenkc6097192002-11-03 00:24:07 +0000641- Real-Time Clock:
642
643 When CFG_CMD_DATE is selected, the type of the RTC
644 has to be selected, too. Define exactly one of the
645 following options:
646
647 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
648 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
649 CONFIG_RTC_MC146818 - use MC146818 RTC
wdenk1cb8e982003-03-06 21:55:29 +0000650 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
wdenkc6097192002-11-03 00:24:07 +0000651 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
wdenk7f70e852003-05-20 14:25:27 +0000652 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
wdenk3bac3512003-03-12 10:41:04 +0000653 CONFIG_RTC_DS164x - use Dallas DS164x RTC
wdenkc6097192002-11-03 00:24:07 +0000654
655- Timestamp Support:
656
wdenk43d96162003-03-06 00:02:04 +0000657 When CONFIG_TIMESTAMP is selected, the timestamp
658 (date and time) of an image is printed by image
659 commands like bootm or iminfo. This option is
660 automatically enabled when you select CFG_CMD_DATE .
wdenkc6097192002-11-03 00:24:07 +0000661
662- Partition Support:
663 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
664 and/or CONFIG_ISO_PARTITION
665
666 If IDE or SCSI support is enabled (CFG_CMD_IDE or
667 CFG_CMD_SCSI) you must configure support for at least
668 one partition type as well.
669
670- IDE Reset method:
671 CONFIG_IDE_RESET_ROUTINE
672
673 Set this to define that instead of a reset Pin, the
674 routine ide_set_reset(int idereset) will be used.
675
676- ATAPI Support:
677 CONFIG_ATAPI
678
679 Set this to enable ATAPI support.
680
681- SCSI Support:
682 At the moment only there is only support for the
683 SYM53C8XX SCSI controller; define
684 CONFIG_SCSI_SYM53C8XX to enable it.
685
686 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
687 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
688 CFG_SCSI_MAX_LUN] can be adjusted to define the
689 maximum numbers of LUNs, SCSI ID's and target
690 devices.
691 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
692
693- NETWORK Support (PCI):
wdenk682011f2003-06-03 23:54:09 +0000694 CONFIG_E1000
695 Support for Intel 8254x gigabit chips.
stroese53cf9432003-06-05 15:39:44 +0000696
wdenkc6097192002-11-03 00:24:07 +0000697 CONFIG_EEPRO100
698 Support for Intel 82557/82559/82559ER chips.
699 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
700 write routine for first time initialisation.
701
702 CONFIG_TULIP
703 Support for Digital 2114x chips.
704 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
705 modem chip initialisation (KS8761/QS6611).
706
707 CONFIG_NATSEMI
708 Support for National dp83815 chips.
709
710 CONFIG_NS8382X
711 Support for National dp8382[01] gigabit chips.
712
wdenk45219c42003-05-12 21:50:16 +0000713- NETWORK Support (other):
714
715 CONFIG_DRIVER_LAN91C96
716 Support for SMSC's LAN91C96 chips.
717
718 CONFIG_LAN91C96_BASE
719 Define this to hold the physical address
720 of the LAN91C96's I/O space
721
722 CONFIG_LAN91C96_USE_32_BIT
723 Define this to enable 32 bit addressing
724
wdenkc6097192002-11-03 00:24:07 +0000725- USB Support:
726 At the moment only the UHCI host controller is
727 supported (PIP405, MIP405); define
728 CONFIG_USB_UHCI to enable it.
729 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
730 end define CONFIG_USB_STORAGE to enable the USB
731 storage devices.
732 Note:
733 Supported are USB Keyboards and USB Floppy drives
734 (TEAC FD-05PUB).
735
wdenk71f95112003-06-15 22:40:42 +0000736- MMC Support:
737 The MMC controller on the Intel PXA is supported. To
738 enable this define CONFIG_MMC. The MMC can be
739 accessed from the boot prompt by mapping the device
740 to physical memory similar to flash. Command line is
741 enabled with CFG_CMD_MMC. The MMC driver also works with
742 the FAT fs. This is enabled with CFG_CMD_FAT.
743
wdenkc6097192002-11-03 00:24:07 +0000744- Keyboard Support:
745 CONFIG_ISA_KEYBOARD
746
747 Define this to enable standard (PC-Style) keyboard
748 support
749
750 CONFIG_I8042_KBD
751 Standard PC keyboard driver with US (is default) and
752 GERMAN key layout (switch via environment 'keymap=de') support.
753 Export function i8042_kbd_init, i8042_tstc and i8042_getc
754 for cfb_console. Supports cursor blinking.
755
756- Video support:
757 CONFIG_VIDEO
758
759 Define this to enable video support (for output to
760 video).
761
762 CONFIG_VIDEO_CT69000
763
764 Enable Chips & Technologies 69000 Video chip
765
766 CONFIG_VIDEO_SMI_LYNXEM
767 Enable Silicon Motion SMI 712/710/810 Video chip
768 Videomode are selected via environment 'videomode' with
769 standard LiLo mode numbers.
770 Following modes are supported (* is default):
771
wdenk43d96162003-03-06 00:02:04 +0000772 800x600 1024x768 1280x1024
773 256 (8bit) 303* 305 307
774 65536 (16bit) 314 317 31a
775 16,7 Mill (24bit) 315 318 31b
wdenkc6097192002-11-03 00:24:07 +0000776 (i.e. setenv videomode 317; saveenv; reset;)
777
stroesec1551ea2003-04-04 15:53:41 +0000778 CONFIG_VIDEO_SED13806
wdenk43d96162003-03-06 00:02:04 +0000779 Enable Epson SED13806 driver. This driver supports 8bpp
wdenka6c7ad22002-12-03 21:28:10 +0000780 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
781 or CONFIG_VIDEO_SED13806_16BPP
782
wdenk682011f2003-06-03 23:54:09 +0000783- Keyboard Support:
784 CONFIG_KEYBOARD
785
786 Define this to enable a custom keyboard support.
787 This simply calls drv_keyboard_init() which must be
788 defined in your board-specific files.
789 The only board using this so far is RBC823.
wdenka6c7ad22002-12-03 21:28:10 +0000790
wdenkc6097192002-11-03 00:24:07 +0000791- LCD Support: CONFIG_LCD
792
793 Define this to enable LCD support (for output to LCD
794 display); also select one of the supported displays
795 by defining one of these:
796
797 CONFIG_NEC_NL6648AC33:
798
799 NEC NL6648AC33-18. Active, color, single scan.
800
801 CONFIG_NEC_NL6648BC20
802
803 NEC NL6648BC20-08. 6.5", 640x480.
804 Active, color, single scan.
805
806 CONFIG_SHARP_16x9
807
808 Sharp 320x240. Active, color, single scan.
809 It isn't 16x9, and I am not sure what it is.
810
811 CONFIG_SHARP_LQ64D341
812
813 Sharp LQ64D341 display, 640x480.
814 Active, color, single scan.
815
816 CONFIG_HLD1045
817
818 HLD1045 display, 640x480.
819 Active, color, single scan.
820
821 CONFIG_OPTREX_BW
822
823 Optrex CBL50840-2 NF-FW 99 22 M5
824 or
825 Hitachi LMG6912RPFC-00T
826 or
827 Hitachi SP14Q002
828
829 320x240. Black & white.
830
831 Normally display is black on white background; define
832 CFG_WHITE_ON_BLACK to get it inverted.
833
wdenkd791b1d2003-04-20 14:04:18 +0000834- Spash Screen Support: CONFIG_SPLASH_SCREEN
835
836 If this option is set, the environment is checked for
837 a variable "splashimage". If found, the usual display
838 of logo, copyright and system information on the LCD
839 is supressed and the BMP image at the address
840 specified in "splashimage" is loaded instead. The
841 console is redirected to the "nulldev", too. This
842 allows for a "silent" boot where a splash screen is
843 loaded very quickly after power-on.
844
845
wdenkc6097192002-11-03 00:24:07 +0000846- Ethernet address:
847 CONFIG_ETHADDR
848 CONFIG_ETH2ADDR
849 CONFIG_ETH3ADDR
850
851 Define a default value for ethernet address to use
852 for the respective ethernet interface, in case this
853 is not determined automatically.
854
855- IP address:
856 CONFIG_IPADDR
857
858 Define a default value for the IP address to use for
859 the default ethernet interface, in case this is not
860 determined through e.g. bootp.
861
862- Server IP address:
863 CONFIG_SERVERIP
864
865 Defines a default value for theIP address of a TFTP
866 server to contact when using the "tftboot" command.
867
868- BOOTP Recovery Mode:
869 CONFIG_BOOTP_RANDOM_DELAY
870
871 If you have many targets in a network that try to
872 boot using BOOTP, you may want to avoid that all
873 systems send out BOOTP requests at precisely the same
874 moment (which would happen for instance at recovery
875 from a power failure, when all systems will try to
876 boot, thus flooding the BOOTP server. Defining
877 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
878 inserted before sending out BOOTP requests. The
879 following delays are insterted then:
880
881 1st BOOTP request: delay 0 ... 1 sec
882 2nd BOOTP request: delay 0 ... 2 sec
883 3rd BOOTP request: delay 0 ... 4 sec
884 4th and following
885 BOOTP requests: delay 0 ... 8 sec
886
887- Status LED: CONFIG_STATUS_LED
888
889 Several configurations allow to display the current
890 status using a LED. For instance, the LED will blink
891 fast while running U-Boot code, stop blinking as
892 soon as a reply to a BOOTP request was received, and
893 start blinking slow once the Linux kernel is running
894 (supported by a status LED driver in the Linux
895 kernel). Defining CONFIG_STATUS_LED enables this
896 feature in U-Boot.
897
898- CAN Support: CONFIG_CAN_DRIVER
899
900 Defining CONFIG_CAN_DRIVER enables CAN driver support
901 on those systems that support this (optional)
902 feature, like the TQM8xxL modules.
903
904- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
905
906 Enables I2C serial bus commands. If this is selected,
907 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
908 to include the appropriate I2C driver.
909
wdenk43d96162003-03-06 00:02:04 +0000910 See also: common/cmd_i2c.c for a description of the
911 command line interface.
wdenkc6097192002-11-03 00:24:07 +0000912
913
914 CONFIG_HARD_I2C
915
916 Selects the CPM hardware driver for I2C.
917
918 CONFIG_SOFT_I2C
919
920 Use software (aka bit-banging) driver instead of CPM
921 or similar hardware support for I2C. This is configured
922 via the following defines.
923
924 I2C_INIT
925
wdenk43d96162003-03-06 00:02:04 +0000926 (Optional). Any commands necessary to enable I2C
927 controller or configure ports.
wdenkc6097192002-11-03 00:24:07 +0000928
929 I2C_PORT
930
wdenk43d96162003-03-06 00:02:04 +0000931 (Only for MPC8260 CPU). The I/O port to use (the code
932 assumes both bits are on the same port). Valid values
933 are 0..3 for ports A..D.
wdenkc6097192002-11-03 00:24:07 +0000934
935 I2C_ACTIVE
936
937 The code necessary to make the I2C data line active
938 (driven). If the data line is open collector, this
939 define can be null.
940
941 I2C_TRISTATE
942
943 The code necessary to make the I2C data line tri-stated
944 (inactive). If the data line is open collector, this
945 define can be null.
946
947 I2C_READ
948
949 Code that returns TRUE if the I2C data line is high,
950 FALSE if it is low.
951
952 I2C_SDA(bit)
953
954 If <bit> is TRUE, sets the I2C data line high. If it
955 is FALSE, it clears it (low).
956
957 I2C_SCL(bit)
958
959 If <bit> is TRUE, sets the I2C clock line high. If it
960 is FALSE, it clears it (low).
961
962 I2C_DELAY
963
964 This delay is invoked four times per clock cycle so this
965 controls the rate of data transfer. The data rate thus
966 is 1 / (I2C_DELAY * 4).
967
wdenk47cd00f2003-03-06 13:39:27 +0000968 CFG_I2C_INIT_BOARD
969
970 When a board is reset during an i2c bus transfer
971 chips might think that the current transfer is still
972 in progress. On some boards it is possible to access
973 the i2c SCLK line directly, either by using the
974 processor pin as a GPIO or by having a second pin
975 connected to the bus. If this option is defined a
976 custom i2c_init_board() routine in boards/xxx/board.c
977 is run early in the boot sequence.
978
wdenkc6097192002-11-03 00:24:07 +0000979- SPI Support: CONFIG_SPI
980
981 Enables SPI driver (so far only tested with
982 SPI EEPROM, also an instance works with Crystal A/D and
983 D/As on the SACSng board)
984
985 CONFIG_SPI_X
986
987 Enables extended (16-bit) SPI EEPROM addressing.
988 (symmetrical to CONFIG_I2C_X)
989
990 CONFIG_SOFT_SPI
991
wdenk43d96162003-03-06 00:02:04 +0000992 Enables a software (bit-bang) SPI driver rather than
993 using hardware support. This is a general purpose
994 driver that only requires three general I/O port pins
995 (two outputs, one input) to function. If this is
996 defined, the board configuration must define several
997 SPI configuration items (port pins to use, etc). For
998 an example, see include/configs/sacsng.h.
wdenkc6097192002-11-03 00:24:07 +0000999
1000- FPGA Support: CONFIG_FPGA_COUNT
1001
wdenk43d96162003-03-06 00:02:04 +00001002 Specify the number of FPGA devices to support.
wdenkc6097192002-11-03 00:24:07 +00001003
wdenk43d96162003-03-06 00:02:04 +00001004 CONFIG_FPGA
wdenkc6097192002-11-03 00:24:07 +00001005
wdenk43d96162003-03-06 00:02:04 +00001006 Used to specify the types of FPGA devices. For
wdenkc6097192002-11-03 00:24:07 +00001007 example,
1008 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1009
1010 CFG_FPGA_PROG_FEEDBACK
1011
wdenk43d96162003-03-06 00:02:04 +00001012 Enable printing of hash marks during FPGA
wdenkc6097192002-11-03 00:24:07 +00001013 configuration.
1014
1015 CFG_FPGA_CHECK_BUSY
1016
wdenk43d96162003-03-06 00:02:04 +00001017 Enable checks on FPGA configuration interface busy
1018 status by the configuration function. This option
1019 will require a board or device specific function to
1020 be written.
wdenkc6097192002-11-03 00:24:07 +00001021
1022 CONFIG_FPGA_DELAY
1023
wdenk43d96162003-03-06 00:02:04 +00001024 If defined, a function that provides delays in the
1025 FPGA configuration driver.
wdenkc6097192002-11-03 00:24:07 +00001026
1027 CFG_FPGA_CHECK_CTRLC
1028
1029 Allow Control-C to interrupt FPGA configuration
1030
1031 CFG_FPGA_CHECK_ERROR
1032
wdenk43d96162003-03-06 00:02:04 +00001033 Check for configuration errors during FPGA bitfile
1034 loading. For example, abort during Virtex II
1035 configuration if the INIT_B line goes low (which
1036 indicated a CRC error).
wdenkc6097192002-11-03 00:24:07 +00001037
1038 CFG_FPGA_WAIT_INIT
1039
wdenk43d96162003-03-06 00:02:04 +00001040 Maximum time to wait for the INIT_B line to deassert
1041 after PROB_B has been deasserted during a Virtex II
1042 FPGA configuration sequence. The default time is 500 mS.
wdenkc6097192002-11-03 00:24:07 +00001043
1044 CFG_FPGA_WAIT_BUSY
1045
wdenk43d96162003-03-06 00:02:04 +00001046 Maximum time to wait for BUSY to deassert during
1047 Virtex II FPGA configuration. The default is 5 mS.
wdenkc6097192002-11-03 00:24:07 +00001048
1049 CFG_FPGA_WAIT_CONFIG
1050
wdenk43d96162003-03-06 00:02:04 +00001051 Time to wait after FPGA configuration. The default is
wdenkc6097192002-11-03 00:24:07 +00001052 200 mS.
1053
1054- FPGA Support: CONFIG_FPGA_COUNT
1055
1056 Specify the number of FPGA devices to support.
1057
1058 CONFIG_FPGA
1059
1060 Used to specify the types of FPGA devices. For example,
1061 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1062
1063 CFG_FPGA_PROG_FEEDBACK
1064
1065 Enable printing of hash marks during FPGA configuration.
1066
1067 CFG_FPGA_CHECK_BUSY
1068
wdenk43d96162003-03-06 00:02:04 +00001069 Enable checks on FPGA configuration interface busy
1070 status by the configuration function. This option
1071 will require a board or device specific function to
1072 be written.
wdenkc6097192002-11-03 00:24:07 +00001073
1074 CONFIG_FPGA_DELAY
1075
1076 If defined, a function that provides delays in the FPGA
1077 configuration driver.
1078
1079 CFG_FPGA_CHECK_CTRLC
1080 Allow Control-C to interrupt FPGA configuration
1081
1082 CFG_FPGA_CHECK_ERROR
1083
wdenk43d96162003-03-06 00:02:04 +00001084 Check for configuration errors during FPGA bitfile
1085 loading. For example, abort during Virtex II
1086 configuration if the INIT_B line goes low (which
1087 indicated a CRC error).
wdenkc6097192002-11-03 00:24:07 +00001088
1089 CFG_FPGA_WAIT_INIT
1090
wdenk43d96162003-03-06 00:02:04 +00001091 Maximum time to wait for the INIT_B line to deassert
1092 after PROB_B has been deasserted during a Virtex II
1093 FPGA configuration sequence. The default time is 500
1094 mS.
wdenkc6097192002-11-03 00:24:07 +00001095
1096 CFG_FPGA_WAIT_BUSY
1097
wdenk43d96162003-03-06 00:02:04 +00001098 Maximum time to wait for BUSY to deassert during
1099 Virtex II FPGA configuration. The default is 5 mS.
wdenkc6097192002-11-03 00:24:07 +00001100
1101 CFG_FPGA_WAIT_CONFIG
1102
wdenk43d96162003-03-06 00:02:04 +00001103 Time to wait after FPGA configuration. The default is
1104 200 mS.
wdenkc6097192002-11-03 00:24:07 +00001105
1106- Configuration Management:
1107 CONFIG_IDENT_STRING
1108
wdenk43d96162003-03-06 00:02:04 +00001109 If defined, this string will be added to the U-Boot
1110 version information (U_BOOT_VERSION)
wdenkc6097192002-11-03 00:24:07 +00001111
1112- Vendor Parameter Protection:
1113
wdenk43d96162003-03-06 00:02:04 +00001114 U-Boot considers the values of the environment
1115 variables "serial#" (Board Serial Number) and
1116 "ethaddr" (Ethernet Address) to bb parameters that
1117 are set once by the board vendor / manufacturer, and
1118 protects these variables from casual modification by
1119 the user. Once set, these variables are read-only,
1120 and write or delete attempts are rejected. You can
1121 change this behviour:
wdenkc6097192002-11-03 00:24:07 +00001122
1123 If CONFIG_ENV_OVERWRITE is #defined in your config
1124 file, the write protection for vendor parameters is
wdenk47cd00f2003-03-06 13:39:27 +00001125 completely disabled. Anybody can change or delete
wdenkc6097192002-11-03 00:24:07 +00001126 these parameters.
1127
1128 Alternatively, if you #define _both_ CONFIG_ETHADDR
1129 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1130 ethernet address is installed in the environment,
1131 which can be changed exactly ONCE by the user. [The
1132 serial# is unaffected by this, i. e. it remains
1133 read-only.]
1134
1135- Protected RAM:
1136 CONFIG_PRAM
1137
1138 Define this variable to enable the reservation of
1139 "protected RAM", i. e. RAM which is not overwritten
1140 by U-Boot. Define CONFIG_PRAM to hold the number of
1141 kB you want to reserve for pRAM. You can overwrite
1142 this default value by defining an environment
1143 variable "pram" to the number of kB you want to
1144 reserve. Note that the board info structure will
1145 still show the full amount of RAM. If pRAM is
1146 reserved, a new environment variable "mem" will
1147 automatically be defined to hold the amount of
1148 remaining RAM in a form that can be passed as boot
1149 argument to Linux, for instance like that:
1150
1151 setenv bootargs ... mem=\$(mem)
1152 saveenv
1153
1154 This way you can tell Linux not to use this memory,
1155 either, which results in a memory region that will
1156 not be affected by reboots.
1157
1158 *WARNING* If your board configuration uses automatic
1159 detection of the RAM size, you must make sure that
1160 this memory test is non-destructive. So far, the
1161 following board configurations are known to be
1162 "pRAM-clean":
1163
1164 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1165 HERMES, IP860, RPXlite, LWMON, LANTEC,
1166 PCU_E, FLAGADM, TQM8260
1167
1168- Error Recovery:
1169 CONFIG_PANIC_HANG
1170
1171 Define this variable to stop the system in case of a
1172 fatal error, so that you have to reset it manually.
1173 This is probably NOT a good idea for an embedded
1174 system where you want to system to reboot
1175 automatically as fast as possible, but it may be
1176 useful during development since you can try to debug
1177 the conditions that lead to the situation.
1178
1179 CONFIG_NET_RETRY_COUNT
1180
wdenk43d96162003-03-06 00:02:04 +00001181 This variable defines the number of retries for
1182 network operations like ARP, RARP, TFTP, or BOOTP
1183 before giving up the operation. If not defined, a
1184 default value of 5 is used.
wdenkc6097192002-11-03 00:24:07 +00001185
1186- Command Interpreter:
1187 CFG_HUSH_PARSER
1188
1189 Define this variable to enable the "hush" shell (from
1190 Busybox) as command line interpreter, thus enabling
1191 powerful command line syntax like
1192 if...then...else...fi conditionals or `&&' and '||'
1193 constructs ("shell scripts").
1194
1195 If undefined, you get the old, much simpler behaviour
1196 with a somewhat smaller memory footprint.
1197
1198
1199 CFG_PROMPT_HUSH_PS2
1200
1201 This defines the secondary prompt string, which is
1202 printed when the command interpreter needs more input
1203 to complete a command. Usually "> ".
1204
1205 Note:
1206
wdenk3b57fe02003-05-30 12:48:29 +00001207 In the current implementation, the local variables
1208 space and global environment variables space are
1209 separated. Local variables are those you define by
1210 simply typing `name=value'. To access a local
1211 variable later on, you have write `$name' or
1212 `${name}'; to execute the contents of a variable
1213 directly type `$name' at the command prompt.
wdenkc6097192002-11-03 00:24:07 +00001214
wdenk43d96162003-03-06 00:02:04 +00001215 Global environment variables are those you use
1216 setenv/printenv to work with. To run a command stored
1217 in such a variable, you need to use the run command,
1218 and you must not use the '$' sign to access them.
wdenkc6097192002-11-03 00:24:07 +00001219
1220 To store commands and special characters in a
1221 variable, please use double quotation marks
1222 surrounding the whole text of the variable, instead
1223 of the backslashes before semicolons and special
1224 symbols.
1225
1226- Default Environment
1227 CONFIG_EXTRA_ENV_SETTINGS
1228
wdenk43d96162003-03-06 00:02:04 +00001229 Define this to contain any number of null terminated
1230 strings (variable = value pairs) that will be part of
1231 the default enviroment compiled into the boot image.
wdenk2262cfe2002-11-18 00:14:45 +00001232
wdenk43d96162003-03-06 00:02:04 +00001233 For example, place something like this in your
1234 board's config file:
wdenkc6097192002-11-03 00:24:07 +00001235
1236 #define CONFIG_EXTRA_ENV_SETTINGS \
1237 "myvar1=value1\0" \
1238 "myvar2=value2\0"
1239
wdenk43d96162003-03-06 00:02:04 +00001240 Warning: This method is based on knowledge about the
1241 internal format how the environment is stored by the
1242 U-Boot code. This is NOT an official, exported
1243 interface! Although it is unlikely that this format
1244 will change soon, but there is no guarantee either.
wdenkc6097192002-11-03 00:24:07 +00001245 You better know what you are doing here.
1246
wdenk43d96162003-03-06 00:02:04 +00001247 Note: overly (ab)use of the default environment is
1248 discouraged. Make sure to check other ways to preset
1249 the environment like the autoscript function or the
1250 boot command first.
wdenkc6097192002-11-03 00:24:07 +00001251
wdenk2abbe072003-06-16 23:50:08 +00001252- DataFlash Support
1253 CONFIG_HAS_DATAFLASH
1254
1255 Defining this option enables DataFlash features and
1256 allows to read/write in Dataflash via the standard
1257 commands cp, md...
1258
wdenkc6097192002-11-03 00:24:07 +00001259- Show boot progress
1260 CONFIG_SHOW_BOOT_PROGRESS
1261
wdenk43d96162003-03-06 00:02:04 +00001262 Defining this option allows to add some board-
1263 specific code (calling a user-provided function
1264 "show_boot_progress(int)") that enables you to show
1265 the system's boot progress on some display (for
1266 example, some LED's) on your board. At the moment,
1267 the following checkpoints are implemented:
wdenkc6097192002-11-03 00:24:07 +00001268
1269 Arg Where When
1270 1 common/cmd_bootm.c before attempting to boot an image
1271 -1 common/cmd_bootm.c Image header has bad magic number
1272 2 common/cmd_bootm.c Image header has correct magic number
1273 -2 common/cmd_bootm.c Image header has bad checksum
1274 3 common/cmd_bootm.c Image header has correct checksum
1275 -3 common/cmd_bootm.c Image data has bad checksum
1276 4 common/cmd_bootm.c Image data has correct checksum
1277 -4 common/cmd_bootm.c Image is for unsupported architecture
1278 5 common/cmd_bootm.c Architecture check OK
1279 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1280 6 common/cmd_bootm.c Image Type check OK
1281 -6 common/cmd_bootm.c gunzip uncompression error
1282 -7 common/cmd_bootm.c Unimplemented compression type
1283 7 common/cmd_bootm.c Uncompression OK
1284 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1285 8 common/cmd_bootm.c Image Type check OK
1286 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1287 9 common/cmd_bootm.c Start initial ramdisk verification
1288 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1289 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1290 10 common/cmd_bootm.c Ramdisk header is OK
1291 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1292 11 common/cmd_bootm.c Ramdisk data has correct checksum
1293 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1294 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1295 13 common/cmd_bootm.c Start multifile image verification
1296 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1297 15 common/cmd_bootm.c All preparation done, transferring control to OS
1298
1299 -1 common/cmd_doc.c Bad usage of "doc" command
1300 -1 common/cmd_doc.c No boot device
1301 -1 common/cmd_doc.c Unknown Chip ID on boot device
1302 -1 common/cmd_doc.c Read Error on boot device
1303 -1 common/cmd_doc.c Image header has bad magic number
1304
1305 -1 common/cmd_ide.c Bad usage of "ide" command
1306 -1 common/cmd_ide.c No boot device
1307 -1 common/cmd_ide.c Unknown boot device
1308 -1 common/cmd_ide.c Unknown partition table
1309 -1 common/cmd_ide.c Invalid partition type
1310 -1 common/cmd_ide.c Read Error on boot device
1311 -1 common/cmd_ide.c Image header has bad magic number
1312
1313 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1314
1315
1316Modem Support:
1317--------------
1318
wdenk85ec0bc2003-03-31 16:34:49 +00001319[so far only for SMDK2400 and TRAB boards]
wdenkc6097192002-11-03 00:24:07 +00001320
1321- Modem support endable:
1322 CONFIG_MODEM_SUPPORT
1323
1324- RTS/CTS Flow control enable:
1325 CONFIG_HWFLOW
1326
1327- Modem debug support:
1328 CONFIG_MODEM_SUPPORT_DEBUG
1329
wdenk43d96162003-03-06 00:02:04 +00001330 Enables debugging stuff (char screen[1024], dbg())
1331 for modem support. Useful only with BDI2000.
wdenkc6097192002-11-03 00:24:07 +00001332
1333- General:
1334
wdenk43d96162003-03-06 00:02:04 +00001335 In the target system modem support is enabled when a
1336 specific key (key combination) is pressed during
1337 power-on. Otherwise U-Boot will boot normally
1338 (autoboot). The key_pressed() fuction is called from
1339 board_init(). Currently key_pressed() is a dummy
1340 function, returning 1 and thus enabling modem
1341 initialization.
wdenkc6097192002-11-03 00:24:07 +00001342
wdenk43d96162003-03-06 00:02:04 +00001343 If there are no modem init strings in the
1344 environment, U-Boot proceed to autoboot; the
1345 previous output (banner, info printfs) will be
1346 supressed, though.
wdenkc6097192002-11-03 00:24:07 +00001347
1348 See also: doc/README.Modem
1349
1350
1351
1352
1353Configuration Settings:
1354-----------------------
1355
1356- CFG_LONGHELP: Defined when you want long help messages included;
1357 undefine this when you're short of memory.
1358
1359- CFG_PROMPT: This is what U-Boot prints on the console to
1360 prompt for user input.
1361
1362- CFG_CBSIZE: Buffer size for input from the Console
1363
1364- CFG_PBSIZE: Buffer size for Console output
1365
1366- CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1367
1368- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1369 the application (usually a Linux kernel) when it is
1370 booted
1371
1372- CFG_BAUDRATE_TABLE:
1373 List of legal baudrate settings for this board.
1374
1375- CFG_CONSOLE_INFO_QUIET
1376 Suppress display of console information at boot.
1377
1378- CFG_CONSOLE_IS_IN_ENV
1379 If the board specific function
1380 extern int overwrite_console (void);
1381 returns 1, the stdin, stderr and stdout are switched to the
1382 serial port, else the settings in the environment are used.
1383
1384- CFG_CONSOLE_OVERWRITE_ROUTINE
1385 Enable the call to overwrite_console().
1386
1387- CFG_CONSOLE_ENV_OVERWRITE
1388 Enable overwrite of previous console environment settings.
1389
1390- CFG_MEMTEST_START, CFG_MEMTEST_END:
1391 Begin and End addresses of the area used by the
1392 simple memory test.
1393
1394- CFG_ALT_MEMTEST:
1395 Enable an alternate, more extensive memory test.
1396
1397- CFG_TFTP_LOADADDR:
1398 Default load address for network file downloads
1399
1400- CFG_LOADS_BAUD_CHANGE:
1401 Enable temporary baudrate change while serial download
1402
1403- CFG_SDRAM_BASE:
1404 Physical start address of SDRAM. _Must_ be 0 here.
1405
1406- CFG_MBIO_BASE:
1407 Physical start address of Motherboard I/O (if using a
1408 Cogent motherboard)
1409
1410- CFG_FLASH_BASE:
1411 Physical start address of Flash memory.
1412
1413- CFG_MONITOR_BASE:
1414 Physical start address of boot monitor code (set by
1415 make config files to be same as the text base address
1416 (TEXT_BASE) used when linking) - same as
1417 CFG_FLASH_BASE when booting from flash.
1418
1419- CFG_MONITOR_LEN:
wdenk3b57fe02003-05-30 12:48:29 +00001420 Size of memory reserved for monitor code, used to
1421 determine _at_compile_time_ (!) if the environment is
1422 embedded within the U-Boot image, or in a separate
1423 flash sector.
wdenkc6097192002-11-03 00:24:07 +00001424
1425- CFG_MALLOC_LEN:
1426 Size of DRAM reserved for malloc() use.
1427
1428- CFG_BOOTMAPSZ:
1429 Maximum size of memory mapped by the startup code of
1430 the Linux kernel; all data that must be processed by
1431 the Linux kernel (bd_info, boot arguments, eventually
1432 initrd image) must be put below this limit.
1433
1434- CFG_MAX_FLASH_BANKS:
1435 Max number of Flash memory banks
1436
1437- CFG_MAX_FLASH_SECT:
1438 Max number of sectors on a Flash chip
1439
1440- CFG_FLASH_ERASE_TOUT:
1441 Timeout for Flash erase operations (in ms)
1442
1443- CFG_FLASH_WRITE_TOUT:
1444 Timeout for Flash write operations (in ms)
1445
1446- CFG_DIRECT_FLASH_TFTP:
1447
1448 Enable TFTP transfers directly to flash memory;
1449 without this option such a download has to be
1450 performed in two steps: (1) download to RAM, and (2)
1451 copy from RAM to flash.
1452
1453 The two-step approach is usually more reliable, since
1454 you can check if the download worked before you erase
1455 the flash, but in some situations (when sytem RAM is
1456 too limited to allow for a tempory copy of the
1457 downloaded image) this option may be very useful.
1458
1459- CFG_FLASH_CFI:
wdenk43d96162003-03-06 00:02:04 +00001460 Define if the flash driver uses extra elements in the
1461 common flash structure for storing flash geometry
wdenkc6097192002-11-03 00:24:07 +00001462
stroese53cf9432003-06-05 15:39:44 +00001463- CFG_RX_ETH_BUFFER:
1464 Defines the number of ethernet receive buffers. On some
1465 ethernet controllers it is recommended to set this value
1466 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1467 buffers can be full shortly after enabling the interface
1468 on high ethernet traffic.
1469 Defaults to 4 if not defined.
1470
wdenkc6097192002-11-03 00:24:07 +00001471The following definitions that deal with the placement and management
1472of environment data (variable area); in general, we support the
1473following configurations:
1474
1475- CFG_ENV_IS_IN_FLASH:
1476
1477 Define this if the environment is in flash memory.
1478
1479 a) The environment occupies one whole flash sector, which is
1480 "embedded" in the text segment with the U-Boot code. This
1481 happens usually with "bottom boot sector" or "top boot
1482 sector" type flash chips, which have several smaller
1483 sectors at the start or the end. For instance, such a
1484 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1485 such a case you would place the environment in one of the
1486 4 kB sectors - with U-Boot code before and after it. With
1487 "top boot sector" type flash chips, you would put the
1488 environment in one of the last sectors, leaving a gap
1489 between U-Boot and the environment.
1490
1491 - CFG_ENV_OFFSET:
1492
1493 Offset of environment data (variable area) to the
1494 beginning of flash memory; for instance, with bottom boot
1495 type flash chips the second sector can be used: the offset
1496 for this sector is given here.
1497
1498 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1499
1500 - CFG_ENV_ADDR:
1501
1502 This is just another way to specify the start address of
1503 the flash sector containing the environment (instead of
1504 CFG_ENV_OFFSET).
1505
1506 - CFG_ENV_SECT_SIZE:
1507
1508 Size of the sector containing the environment.
1509
1510
1511 b) Sometimes flash chips have few, equal sized, BIG sectors.
1512 In such a case you don't want to spend a whole sector for
1513 the environment.
1514
1515 - CFG_ENV_SIZE:
1516
1517 If you use this in combination with CFG_ENV_IS_IN_FLASH
1518 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1519 of this flash sector for the environment. This saves
1520 memory for the RAM copy of the environment.
1521
1522 It may also save flash memory if you decide to use this
1523 when your environment is "embedded" within U-Boot code,
1524 since then the remainder of the flash sector could be used
1525 for U-Boot code. It should be pointed out that this is
1526 STRONGLY DISCOURAGED from a robustness point of view:
1527 updating the environment in flash makes it always
1528 necessary to erase the WHOLE sector. If something goes
1529 wrong before the contents has been restored from a copy in
1530 RAM, your target system will be dead.
1531
1532 - CFG_ENV_ADDR_REDUND
1533 CFG_ENV_SIZE_REDUND
1534
wdenk43d96162003-03-06 00:02:04 +00001535 These settings describe a second storage area used to hold
1536 a redundand copy of the environment data, so that there is
wdenk3e386912003-04-05 00:53:31 +00001537 a valid backup copy in case there is a power failure during
wdenk43d96162003-03-06 00:02:04 +00001538 a "saveenv" operation.
wdenkc6097192002-11-03 00:24:07 +00001539
1540BE CAREFUL! Any changes to the flash layout, and some changes to the
1541source code will make it necessary to adapt <board>/u-boot.lds*
1542accordingly!
1543
1544
1545- CFG_ENV_IS_IN_NVRAM:
1546
1547 Define this if you have some non-volatile memory device
1548 (NVRAM, battery buffered SRAM) which you want to use for the
1549 environment.
1550
1551 - CFG_ENV_ADDR:
1552 - CFG_ENV_SIZE:
1553
1554 These two #defines are used to determin the memory area you
1555 want to use for environment. It is assumed that this memory
1556 can just be read and written to, without any special
1557 provision.
1558
1559BE CAREFUL! The first access to the environment happens quite early
1560in U-Boot initalization (when we try to get the setting of for the
1561console baudrate). You *MUST* have mappend your NVRAM area then, or
1562U-Boot will hang.
1563
1564Please note that even with NVRAM we still use a copy of the
1565environment in RAM: we could work on NVRAM directly, but we want to
1566keep settings there always unmodified except somebody uses "saveenv"
1567to save the current settings.
1568
1569
1570- CFG_ENV_IS_IN_EEPROM:
1571
1572 Use this if you have an EEPROM or similar serial access
1573 device and a driver for it.
1574
1575 - CFG_ENV_OFFSET:
1576 - CFG_ENV_SIZE:
1577
1578 These two #defines specify the offset and size of the
1579 environment area within the total memory of your EEPROM.
1580
1581 - CFG_I2C_EEPROM_ADDR:
1582 If defined, specified the chip address of the EEPROM device.
1583 The default address is zero.
1584
1585 - CFG_EEPROM_PAGE_WRITE_BITS:
1586 If defined, the number of bits used to address bytes in a
1587 single page in the EEPROM device. A 64 byte page, for example
1588 would require six bits.
1589
1590 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1591 If defined, the number of milliseconds to delay between
1592 page writes. The default is zero milliseconds.
1593
1594 - CFG_I2C_EEPROM_ADDR_LEN:
1595 The length in bytes of the EEPROM memory array address. Note
1596 that this is NOT the chip address length!
1597
1598 - CFG_EEPROM_SIZE:
1599 The size in bytes of the EEPROM device.
1600
wdenkc6097192002-11-03 00:24:07 +00001601
1602- CFG_SPI_INIT_OFFSET
1603
1604 Defines offset to the initial SPI buffer area in DPRAM. The
1605 area is used at an early stage (ROM part) if the environment
1606 is configured to reside in the SPI EEPROM: We need a 520 byte
1607 scratch DPRAM area. It is used between the two initialization
1608 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1609 to be a good choice since it makes it far enough from the
1610 start of the data area as well as from the stack pointer.
1611
1612Please note that the environment is read-only as long as the monitor
1613has been relocated to RAM and a RAM copy of the environment has been
1614created; also, when using EEPROM you will have to use getenv_r()
1615until then to read environment variables.
1616
wdenk85ec0bc2003-03-31 16:34:49 +00001617The environment is protected by a CRC32 checksum. Before the monitor
1618is relocated into RAM, as a result of a bad CRC you will be working
1619with the compiled-in default environment - *silently*!!! [This is
1620necessary, because the first environment variable we need is the
1621"baudrate" setting for the console - if we have a bad CRC, we don't
1622have any device yet where we could complain.]
wdenkc6097192002-11-03 00:24:07 +00001623
1624Note: once the monitor has been relocated, then it will complain if
1625the default environment is used; a new CRC is computed as soon as you
wdenk85ec0bc2003-03-31 16:34:49 +00001626use the "saveenv" command to store a valid environment.
wdenkc6097192002-11-03 00:24:07 +00001627
1628
wdenkc6097192002-11-03 00:24:07 +00001629Low Level (hardware related) configuration options:
wdenkdc7c9a12003-03-26 06:55:25 +00001630---------------------------------------------------
wdenkc6097192002-11-03 00:24:07 +00001631
1632- CFG_CACHELINE_SIZE:
1633 Cache Line Size of the CPU.
1634
1635- CFG_DEFAULT_IMMR:
1636 Default address of the IMMR after system reset.
1637 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1638 to be able to adjust the position of the IMMR
1639 register after a reset.
1640
wdenk7f6c2cb2002-11-10 22:06:23 +00001641- Floppy Disk Support:
1642 CFG_FDC_DRIVE_NUMBER
1643
1644 the default drive number (default value 0)
1645
1646 CFG_ISA_IO_STRIDE
1647
1648 defines the spacing between fdc chipset registers
1649 (default value 1)
1650
1651 CFG_ISA_IO_OFFSET
1652
wdenk43d96162003-03-06 00:02:04 +00001653 defines the offset of register from address. It
1654 depends on which part of the data bus is connected to
1655 the fdc chipset. (default value 0)
wdenk7f6c2cb2002-11-10 22:06:23 +00001656
wdenk43d96162003-03-06 00:02:04 +00001657 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1658 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1659 default value.
wdenk7f6c2cb2002-11-10 22:06:23 +00001660
wdenk43d96162003-03-06 00:02:04 +00001661 if CFG_FDC_HW_INIT is defined, then the function
1662 fdc_hw_init() is called at the beginning of the FDC
1663 setup. fdc_hw_init() must be provided by the board
1664 source code. It is used to make hardware dependant
1665 initializations.
wdenk7f6c2cb2002-11-10 22:06:23 +00001666
wdenkc6097192002-11-03 00:24:07 +00001667- CFG_IMMR: Physical address of the Internal Memory Mapped
1668 Register; DO NOT CHANGE! (11-4)
1669 [MPC8xx systems only]
1670
1671- CFG_INIT_RAM_ADDR:
1672
1673 Start address of memory area tha can be used for
1674 initial data and stack; please note that this must be
1675 writable memory that is working WITHOUT special
1676 initialization, i. e. you CANNOT use normal RAM which
1677 will become available only after programming the
1678 memory controller and running certain initialization
1679 sequences.
1680
1681 U-Boot uses the following memory types:
1682 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1683 - MPC824X: data cache
1684 - PPC4xx: data cache
1685
wdenk85ec0bc2003-03-31 16:34:49 +00001686- CFG_GBL_DATA_OFFSET:
wdenkc6097192002-11-03 00:24:07 +00001687
1688 Offset of the initial data structure in the memory
1689 area defined by CFG_INIT_RAM_ADDR. Usually
wdenk85ec0bc2003-03-31 16:34:49 +00001690 CFG_GBL_DATA_OFFSET is chosen such that the initial
wdenkc6097192002-11-03 00:24:07 +00001691 data is located at the end of the available space
1692 (sometimes written as (CFG_INIT_RAM_END -
1693 CFG_INIT_DATA_SIZE), and the initial stack is just
1694 below that area (growing from (CFG_INIT_RAM_ADDR +
wdenk85ec0bc2003-03-31 16:34:49 +00001695 CFG_GBL_DATA_OFFSET) downward.
wdenkc6097192002-11-03 00:24:07 +00001696
1697 Note:
1698 On the MPC824X (or other systems that use the data
1699 cache for initial memory) the address chosen for
1700 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1701 point to an otherwise UNUSED address space between
1702 the top of RAM and the start of the PCI space.
1703
1704- CFG_SIUMCR: SIU Module Configuration (11-6)
1705
1706- CFG_SYPCR: System Protection Control (11-9)
1707
1708- CFG_TBSCR: Time Base Status and Control (11-26)
1709
1710- CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1711
1712- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1713
1714- CFG_SCCR: System Clock and reset Control Register (15-27)
1715
1716- CFG_OR_TIMING_SDRAM:
1717 SDRAM timing
1718
1719- CFG_MAMR_PTA:
1720 periodic timer for refresh
1721
1722- CFG_DER: Debug Event Register (37-47)
1723
1724- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1725 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1726 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1727 CFG_BR1_PRELIM:
1728 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1729
1730- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1731 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1732 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1733 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1734
1735- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1736 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1737 Machine Mode Register and Memory Periodic Timer
1738 Prescaler definitions (SDRAM timing)
1739
1740- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1741 enable I2C microcode relocation patch (MPC8xx);
1742 define relocation offset in DPRAM [DSP2]
1743
1744- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1745 enable SPI microcode relocation patch (MPC8xx);
1746 define relocation offset in DPRAM [SCC4]
1747
1748- CFG_USE_OSCCLK:
1749 Use OSCM clock mode on MBX8xx board. Be careful,
1750 wrong setting might damage your board. Read
1751 doc/README.MBX before setting this variable!
1752
wdenkea909b72002-11-21 23:11:29 +00001753- CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
wdenk43d96162003-03-06 00:02:04 +00001754 Offset of the bootmode word in DPRAM used by post
1755 (Power On Self Tests). This definition overrides
1756 #define'd default value in commproc.h resp.
1757 cpm_8260.h.
wdenkea909b72002-11-21 23:11:29 +00001758
stroese1d49b1f2003-05-23 11:39:05 +00001759- CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1760 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1761 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1762 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1763 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1764 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1765 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
wdenk5d232d02003-05-22 22:52:13 +00001766 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1767 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1768
wdenkc6097192002-11-03 00:24:07 +00001769Building the Software:
1770======================
1771
1772Building U-Boot has been tested in native PPC environments (on a
1773PowerBook G3 running LinuxPPC 2000) and in cross environments
1774(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1775NetBSD 1.5 on x86).
1776
1777If you are not using a native PPC environment, it is assumed that you
1778have the GNU cross compiling tools available in your path and named
1779with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1780you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1781the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1782change it to:
1783
1784 CROSS_COMPILE = ppc_4xx-
1785
1786
1787U-Boot is intended to be simple to build. After installing the
1788sources you must configure U-Boot for one specific board type. This
1789is done by typing:
1790
1791 make NAME_config
1792
1793where "NAME_config" is the name of one of the existing
1794configurations; the following names are supported:
1795
1796 ADCIOP_config GTH_config TQM850L_config
1797 ADS860_config IP860_config TQM855L_config
1798 AR405_config IVML24_config TQM860L_config
1799 CANBT_config IVMS8_config WALNUT405_config
1800 CPCI405_config LANTEC_config cogent_common_config
1801 CPCIISER4_config MBX_config cogent_mpc8260_config
1802 CU824_config MBX860T_config cogent_mpc8xx_config
1803 ESTEEM192E_config RPXlite_config hermes_config
1804 ETX094_config RPXsuper_config hymod_config
1805 FADS823_config SM850_config lwmon_config
1806 FADS850SAR_config SPD823TS_config pcu_e_config
1807 FADS860T_config SXNI855T_config rsdproto_config
1808 FPS850L_config Sandpoint8240_config sbc8260_config
1809 GENIETV_config TQM823L_config PIP405_config
wdenk384ae022002-11-05 00:17:55 +00001810 GEN860T_config EBONY_config FPS860L_config
wdenk7f70e852003-05-20 14:25:27 +00001811 ELPT860_config cmi_mpc5xx_config NETVIA_config
wdenk2abbe072003-06-16 23:50:08 +00001812 at91rm9200dk_config
wdenkc6097192002-11-03 00:24:07 +00001813
1814Note: for some board special configuration names may exist; check if
1815 additional information is available from the board vendor; for
1816 instance, the TQM8xxL systems run normally at 50 MHz and use a
1817 SCC for 10baseT ethernet; there are also systems with 80 MHz
1818 CPU clock, and an optional Fast Ethernet module is available
1819 for CPU's with FEC. You can select such additional "features"
1820 when chosing the configuration, i. e.
1821
1822 make TQM860L_config
1823 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1824
1825 make TQM860L_FEC_config
1826 - will configure for a TQM860L at 50MHz with FEC for ethernet
1827
1828 make TQM860L_80MHz_config
1829 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1830 interface
1831
1832 make TQM860L_FEC_80MHz_config
1833 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1834
1835 make TQM823L_LCD_config
1836 - will configure for a TQM823L with U-Boot console on LCD
1837
1838 make TQM823L_LCD_80MHz_config
1839 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1840
1841 etc.
1842
1843
1844
wdenk24ee89b2002-11-03 17:56:27 +00001845Finally, type "make all", and you should get some working U-Boot
wdenkc6097192002-11-03 00:24:07 +00001846images ready for downlod to / installation on your system:
1847
1848- "u-boot.bin" is a raw binary image
1849- "u-boot" is an image in ELF binary format
1850- "u-boot.srec" is in Motorola S-Record format
1851
1852
1853Please be aware that the Makefiles assume you are using GNU make, so
1854for instance on NetBSD you might need to use "gmake" instead of
1855native "make".
1856
1857
1858If the system board that you have is not listed, then you will need
1859to port U-Boot to your hardware platform. To do this, follow these
1860steps:
1861
18621. Add a new configuration option for your board to the toplevel
wdenk85ec0bc2003-03-31 16:34:49 +00001863 "Makefile" and to the "MAKEALL" script, using the existing
1864 entries as examples. Note that here and at many other places
1865 boards and other names are listed alphabetically sorted. Please
1866 keep this order.
wdenkc6097192002-11-03 00:24:07 +000018672. Create a new directory to hold your board specific code. Add any
wdenk85ec0bc2003-03-31 16:34:49 +00001868 files you need. In your board directory, you will need at least
1869 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
18703. Create a new configuration file "include/configs/<board>.h" for
1871 your board
wdenkc6097192002-11-03 00:24:07 +000018723. If you're porting U-Boot to a new CPU, then also create a new
1873 directory to hold your CPU specific code. Add any files you need.
wdenk85ec0bc2003-03-31 16:34:49 +000018744. Run "make <board>_config" with your new name.
wdenkc6097192002-11-03 00:24:07 +000018755. Type "make", and you should get a working "u-boot.srec" file
1876 to be installed on your target system.
wdenk85ec0bc2003-03-31 16:34:49 +000018776. Debug and solve any problems that might arise.
wdenkc6097192002-11-03 00:24:07 +00001878 [Of course, this last step is much harder than it sounds.]
1879
1880
1881Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1882==============================================================
1883
1884If you have modified U-Boot sources (for instance added a new board
1885or support for new devices, a new CPU, etc.) you are expected to
1886provide feedback to the other developers. The feedback normally takes
1887the form of a "patch", i. e. a context diff against a certain (latest
1888official or latest in CVS) version of U-Boot sources.
1889
1890But before you submit such a patch, please verify that your modifi-
1891cation did not break existing code. At least make sure that *ALL* of
1892the supported boards compile WITHOUT ANY compiler warnings. To do so,
1893just run the "MAKEALL" script, which will configure and build U-Boot
1894for ALL supported system. Be warned, this will take a while. You can
1895select which (cross) compiler to use py passing a `CROSS_COMPILE'
1896environment variable to the script, i. e. to use the cross tools from
1897MontaVista's Hard Hat Linux you can type
1898
1899 CROSS_COMPILE=ppc_8xx- MAKEALL
1900
1901or to build on a native PowerPC system you can type
1902
1903 CROSS_COMPILE=' ' MAKEALL
1904
1905See also "U-Boot Porting Guide" below.
1906
1907
1908
1909Monitor Commands - Overview:
1910============================
1911
1912go - start application at address 'addr'
1913run - run commands in an environment variable
1914bootm - boot application image from memory
1915bootp - boot image via network using BootP/TFTP protocol
1916tftpboot- boot image via network using TFTP protocol
1917 and env variables "ipaddr" and "serverip"
1918 (and eventually "gatewayip")
1919rarpboot- boot image via network using RARP/TFTP protocol
1920diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1921loads - load S-Record file over serial line
1922loadb - load binary file over serial line (kermit mode)
1923md - memory display
1924mm - memory modify (auto-incrementing)
1925nm - memory modify (constant address)
1926mw - memory write (fill)
1927cp - memory copy
1928cmp - memory compare
1929crc32 - checksum calculation
1930imd - i2c memory display
1931imm - i2c memory modify (auto-incrementing)
1932inm - i2c memory modify (constant address)
1933imw - i2c memory write (fill)
1934icrc32 - i2c checksum calculation
1935iprobe - probe to discover valid I2C chip addresses
1936iloop - infinite loop on address range
1937isdram - print SDRAM configuration information
1938sspi - SPI utility commands
1939base - print or set address offset
1940printenv- print environment variables
1941setenv - set environment variables
1942saveenv - save environment variables to persistent storage
1943protect - enable or disable FLASH write protection
1944erase - erase FLASH memory
1945flinfo - print FLASH memory information
1946bdinfo - print Board Info structure
1947iminfo - print header information for application image
1948coninfo - print console devices and informations
1949ide - IDE sub-system
1950loop - infinite loop on address range
1951mtest - simple RAM test
1952icache - enable or disable instruction cache
1953dcache - enable or disable data cache
1954reset - Perform RESET of the CPU
1955echo - echo args to console
1956version - print monitor version
1957help - print online help
1958? - alias for 'help'
1959
1960
1961Monitor Commands - Detailed Description:
1962========================================
1963
1964TODO.
1965
1966For now: just type "help <command>".
1967
1968
1969Environment Variables:
1970======================
1971
1972U-Boot supports user configuration using Environment Variables which
1973can be made persistent by saving to Flash memory.
1974
1975Environment Variables are set using "setenv", printed using
1976"printenv", and saved to Flash using "saveenv". Using "setenv"
1977without a value can be used to delete a variable from the
1978environment. As long as you don't save the environment you are
1979working with an in-memory copy. In case the Flash area containing the
1980environment is erased by accident, a default environment is provided.
1981
1982Some configuration options can be set using Environment Variables:
1983
1984 baudrate - see CONFIG_BAUDRATE
1985
1986 bootdelay - see CONFIG_BOOTDELAY
1987
1988 bootcmd - see CONFIG_BOOTCOMMAND
1989
1990 bootargs - Boot arguments when booting an RTOS image
1991
1992 bootfile - Name of the image to load with TFTP
1993
1994 autoload - if set to "no" (any string beginning with 'n'),
1995 "bootp" will just load perform a lookup of the
1996 configuration from the BOOTP server, but not try to
1997 load any image using TFTP
1998
1999 autostart - if set to "yes", an image loaded using the "bootp",
2000 "rarpboot", "tftpboot" or "diskboot" commands will
2001 be automatically started (by internally calling
2002 "bootm")
2003
wdenk4a6fd342003-04-12 23:38:12 +00002004 If set to "no", a standalone image passed to the
2005 "bootm" command will be copied to the load address
2006 (and eventually uncompressed), but NOT be started.
2007 This can be used to load and uncompress arbitrary
2008 data.
2009
wdenkc6097192002-11-03 00:24:07 +00002010 initrd_high - restrict positioning of initrd images:
2011 If this variable is not set, initrd images will be
2012 copied to the highest possible address in RAM; this
2013 is usually what you want since it allows for
2014 maximum initrd size. If for some reason you want to
2015 make sure that the initrd image is loaded below the
2016 CFG_BOOTMAPSZ limit, you can set this environment
2017 variable to a value of "no" or "off" or "0".
2018 Alternatively, you can set it to a maximum upper
2019 address to use (U-Boot will still check that it
2020 does not overwrite the U-Boot stack and data).
2021
2022 For instance, when you have a system with 16 MB
2023 RAM, and want to reseve 4 MB from use by Linux,
2024 you can do this by adding "mem=12M" to the value of
2025 the "bootargs" variable. However, now you must make
2026 sure, that the initrd image is placed in the first
2027 12 MB as well - this can be done with
2028
2029 setenv initrd_high 00c00000
2030
wdenk38b99262003-05-23 23:18:21 +00002031 If you set initrd_high to 0xFFFFFFFF, this is an
2032 indication to U-Boot that all addresses are legal
2033 for the Linux kernel, including addresses in flash
2034 memory. In this case U-Boot will NOT COPY the
2035 ramdisk at all. This may be useful to reduce the
2036 boot time on your system, but requires that this
2037 feature is supported by your Linux kernel.
2038
wdenkc6097192002-11-03 00:24:07 +00002039 ipaddr - IP address; needed for tftpboot command
2040
2041 loadaddr - Default load address for commands like "bootp",
wdenkdc7c9a12003-03-26 06:55:25 +00002042 "rarpboot", "tftpboot", "loadb" or "diskboot"
wdenkc6097192002-11-03 00:24:07 +00002043
2044 loads_echo - see CONFIG_LOADS_ECHO
2045
2046 serverip - TFTP server IP address; needed for tftpboot command
2047
2048 bootretry - see CONFIG_BOOT_RETRY_TIME
2049
2050 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2051
2052 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2053
2054
2055The following environment variables may be used and automatically
2056updated by the network boot commands ("bootp" and "rarpboot"),
2057depending the information provided by your boot server:
2058
2059 bootfile - see above
2060 dnsip - IP address of your Domain Name Server
2061 gatewayip - IP address of the Gateway (Router) to use
2062 hostname - Target hostname
2063 ipaddr - see above
2064 netmask - Subnet Mask
2065 rootpath - Pathname of the root filesystem on the NFS server
2066 serverip - see above
2067
2068
2069There are two special Environment Variables:
2070
2071 serial# - contains hardware identification information such
2072 as type string and/or serial number
2073 ethaddr - Ethernet address
2074
2075These variables can be set only once (usually during manufacturing of
2076the board). U-Boot refuses to delete or overwrite these variables
2077once they have been set once.
2078
2079
stroesec1551ea2003-04-04 15:53:41 +00002080Further special Environment Variables:
2081
2082 ver - Contains the U-Boot version string as printed
2083 with the "version" command. This variable is
2084 readonly (see CONFIG_VERSION_VARIABLE).
2085
2086
wdenkc6097192002-11-03 00:24:07 +00002087Please note that changes to some configuration parameters may take
2088only effect after the next boot (yes, that's just like Windoze :-).
2089
2090
wdenkf07771c2003-05-28 08:06:31 +00002091Command Line Parsing:
2092=====================
2093
2094There are two different command line parsers available with U-Boot:
2095the old "simple" one, and the much more pwerful "hush" shell:
2096
2097Old, simple command line parser:
2098--------------------------------
2099
2100- supports environment variables (through setenv / saveenv commands)
2101- several commands on one line, separated by ';'
2102- variable substitution using "... $(name) ..." syntax
2103- special characters ('$', ';') can be escaped by prefixing with '\',
2104 for example:
2105 setenv bootcmd bootm \$(address)
2106- You can also escape text by enclosing in single apostrophes, for example:
2107 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2108
2109Hush shell:
2110-----------
2111
2112- similar to Bourne shell, with control structures like
2113 if...then...else...fi, for...do...done; while...do...done,
2114 until...do...done, ...
2115- supports environment ("global") variables (through setenv / saveenv
2116 commands) and local shell variables (through standard shell syntax
2117 "name=value"); only environment variables can be used with "run"
2118 command
2119
2120General rules:
2121--------------
2122
2123(1) If a command line (or an environment variable executed by a "run"
2124 command) contains several commands separated by semicolon, and
2125 one of these commands fails, then the remaining commands will be
2126 executed anyway.
2127
2128(2) If you execute several variables with one call to run (i. e.
2129 calling run with a list af variables as arguments), any failing
2130 command will cause "run" to terminate, i. e. the remaining
2131 variables are not executed.
2132
wdenkc6097192002-11-03 00:24:07 +00002133Note for Redundant Ethernet Interfaces:
2134=======================================
2135
2136Some boards come with redundand ethernet interfaces; U-Boot supports
2137such configurations and is capable of automatic selection of a
2138"working" interface when needed. MAC assignemnt works as follows:
2139
2140Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2141MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2142"eth1addr" (=>eth1), "eth2addr", ...
2143
2144If the network interface stores some valid MAC address (for instance
2145in SROM), this is used as default address if there is NO correspon-
2146ding setting in the environment; if the corresponding environment
2147variable is set, this overrides the settings in the card; that means:
2148
2149o If the SROM has a valid MAC address, and there is no address in the
2150 environment, the SROM's address is used.
2151
2152o If there is no valid address in the SROM, and a definition in the
2153 environment exists, then the value from the environment variable is
2154 used.
2155
2156o If both the SROM and the environment contain a MAC address, and
2157 both addresses are the same, this MAC address is used.
2158
2159o If both the SROM and the environment contain a MAC address, and the
2160 addresses differ, the value from the environment is used and a
2161 warning is printed.
2162
2163o If neither SROM nor the environment contain a MAC address, an error
2164 is raised.
2165
2166
2167
2168Image Formats:
2169==============
2170
2171The "boot" commands of this monitor operate on "image" files which
2172can be basicly anything, preceeded by a special header; see the
2173definitions in include/image.h for details; basicly, the header
2174defines the following image properties:
2175
2176* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2177 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
wdenk7f70e852003-05-20 14:25:27 +00002178 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2179 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
wdenkc6097192002-11-03 00:24:07 +00002180* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2181 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2182 Currently supported: PowerPC).
2183* Compression Type (Provisions for uncompressed, gzip, bzip2;
2184 Currently supported: uncompressed, gzip).
2185* Load Address
2186* Entry Point
2187* Image Name
2188* Image Timestamp
2189
2190The header is marked by a special Magic Number, and both the header
2191and the data portions of the image are secured against corruption by
2192CRC32 checksums.
2193
2194
2195Linux Support:
2196==============
2197
2198Although U-Boot should support any OS or standalone application
2199easily, Linux has always been in the focus during the design of
2200U-Boot.
2201
2202U-Boot includes many features that so far have been part of some
2203special "boot loader" code within the Linux kernel. Also, any
2204"initrd" images to be used are no longer part of one big Linux image;
2205instead, kernel and "initrd" are separate images. This implementation
2206serves serveral purposes:
2207
2208- the same features can be used for other OS or standalone
2209 applications (for instance: using compressed images to reduce the
2210 Flash memory footprint)
2211
2212- it becomes much easier to port new Linux kernel versions because
2213 lots of low-level, hardware dependend stuff are done by U-Boot
2214
2215- the same Linux kernel image can now be used with different "initrd"
2216 images; of course this also means that different kernel images can
2217 be run with the same "initrd". This makes testing easier (you don't
2218 have to build a new "zImage.initrd" Linux image when you just
2219 change a file in your "initrd"). Also, a field-upgrade of the
2220 software is easier now.
2221
2222
2223Linux HOWTO:
2224============
2225
2226Porting Linux to U-Boot based systems:
2227---------------------------------------
2228
2229U-Boot cannot save you from doing all the necessary modifications to
2230configure the Linux device drivers for use with your target hardware
2231(no, we don't intend to provide a full virtual machine interface to
2232Linux :-).
2233
2234But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2235
2236Just make sure your machine specific header file (for instance
2237include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2238Information structure as we define in include/u-boot.h, and make
2239sure that your definition of IMAP_ADDR uses the same value as your
2240U-Boot configuration in CFG_IMMR.
2241
2242
2243Configuring the Linux kernel:
2244-----------------------------
2245
2246No specific requirements for U-Boot. Make sure you have some root
2247device (initial ramdisk, NFS) for your target system.
2248
2249
2250Building a Linux Image:
2251-----------------------
2252
wdenk24ee89b2002-11-03 17:56:27 +00002253With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2254not used. If you use recent kernel source, a new build target
2255"uImage" will exist which automatically builds an image usable by
2256U-Boot. Most older kernels also have support for a "pImage" target,
2257which was introduced for our predecessor project PPCBoot and uses a
2258100% compatible format.
wdenkc6097192002-11-03 00:24:07 +00002259
2260Example:
2261
2262 make TQM850L_config
2263 make oldconfig
2264 make dep
wdenk24ee89b2002-11-03 17:56:27 +00002265 make uImage
wdenkc6097192002-11-03 00:24:07 +00002266
wdenk24ee89b2002-11-03 17:56:27 +00002267The "uImage" build target uses a special tool (in 'tools/mkimage') to
2268encapsulate a compressed Linux kernel image with header information,
2269CRC32 checksum etc. for use with U-Boot. This is what we are doing:
wdenkc6097192002-11-03 00:24:07 +00002270
wdenk24ee89b2002-11-03 17:56:27 +00002271* build a standard "vmlinux" kernel image (in ELF binary format):
wdenkc6097192002-11-03 00:24:07 +00002272
wdenk24ee89b2002-11-03 17:56:27 +00002273* convert the kernel into a raw binary image:
2274
2275 ${CROSS_COMPILE}-objcopy -O binary \
2276 -R .note -R .comment \
2277 -S vmlinux linux.bin
2278
2279* compress the binary image:
2280
2281 gzip -9 linux.bin
2282
2283* package compressed binary image for U-Boot:
2284
2285 mkimage -A ppc -O linux -T kernel -C gzip \
2286 -a 0 -e 0 -n "Linux Kernel Image" \
2287 -d linux.bin.gz uImage
2288
2289
2290The "mkimage" tool can also be used to create ramdisk images for use
2291with U-Boot, either separated from the Linux kernel image, or
2292combined into one file. "mkimage" encapsulates the images with a 64
2293byte header containing information about target architecture,
2294operating system, image type, compression method, entry points, time
2295stamp, CRC32 checksums, etc.
2296
2297"mkimage" can be called in two ways: to verify existing images and
2298print the header information, or to build new images.
2299
2300In the first form (with "-l" option) mkimage lists the information
2301contained in the header of an existing U-Boot image; this includes
wdenkc6097192002-11-03 00:24:07 +00002302checksum verification:
2303
2304 tools/mkimage -l image
2305 -l ==> list image header information
2306
2307The second form (with "-d" option) is used to build a U-Boot image
2308from a "data file" which is used as image payload:
2309
2310 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2311 -n name -d data_file image
2312 -A ==> set architecture to 'arch'
2313 -O ==> set operating system to 'os'
2314 -T ==> set image type to 'type'
2315 -C ==> set compression type 'comp'
2316 -a ==> set load address to 'addr' (hex)
2317 -e ==> set entry point to 'ep' (hex)
2318 -n ==> set image name to 'name'
2319 -d ==> use image data from 'datafile'
2320
2321Right now, all Linux kernels use the same load address (0x00000000),
2322but the entry point address depends on the kernel version:
2323
2324- 2.2.x kernels have the entry point at 0x0000000C,
wdenk24ee89b2002-11-03 17:56:27 +00002325- 2.3.x and later kernels have the entry point at 0x00000000.
wdenkc6097192002-11-03 00:24:07 +00002326
2327So a typical call to build a U-Boot image would read:
2328
wdenk24ee89b2002-11-03 17:56:27 +00002329 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2330 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2331 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2332 > examples/uImage.TQM850L
2333 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002334 Created: Wed Jul 19 02:34:59 2000
2335 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2336 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2337 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002338 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002339
2340To verify the contents of the image (or check for corruption):
2341
wdenk24ee89b2002-11-03 17:56:27 +00002342 -> tools/mkimage -l examples/uImage.TQM850L
2343 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002344 Created: Wed Jul 19 02:34:59 2000
2345 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2346 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2347 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002348 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002349
2350NOTE: for embedded systems where boot time is critical you can trade
2351speed for memory and install an UNCOMPRESSED image instead: this
2352needs more space in Flash, but boots much faster since it does not
2353need to be uncompressed:
2354
wdenk24ee89b2002-11-03 17:56:27 +00002355 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2356 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2357 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2358 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2359 > examples/uImage.TQM850L-uncompressed
2360 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002361 Created: Wed Jul 19 02:34:59 2000
2362 Image Type: PowerPC Linux Kernel Image (uncompressed)
2363 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2364 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002365 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002366
2367
2368Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2369when your kernel is intended to use an initial ramdisk:
2370
2371 -> tools/mkimage -n 'Simple Ramdisk Image' \
2372 > -A ppc -O linux -T ramdisk -C gzip \
2373 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2374 Image Name: Simple Ramdisk Image
2375 Created: Wed Jan 12 14:01:50 2000
2376 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2377 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2378 Load Address: 0x00000000
2379 Entry Point: 0x00000000
2380
2381
2382Installing a Linux Image:
2383-------------------------
2384
2385To downloading a U-Boot image over the serial (console) interface,
2386you must convert the image to S-Record format:
2387
2388 objcopy -I binary -O srec examples/image examples/image.srec
2389
2390The 'objcopy' does not understand the information in the U-Boot
2391image header, so the resulting S-Record file will be relative to
2392address 0x00000000. To load it to a given address, you need to
2393specify the target address as 'offset' parameter with the 'loads'
2394command.
2395
2396Example: install the image to address 0x40100000 (which on the
2397TQM8xxL is in the first Flash bank):
2398
2399 => erase 40100000 401FFFFF
2400
2401 .......... done
2402 Erased 8 sectors
2403
2404 => loads 40100000
2405 ## Ready for S-Record download ...
2406 ~>examples/image.srec
2407 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2408 ...
2409 15989 15990 15991 15992
2410 [file transfer complete]
2411 [connected]
2412 ## Start Addr = 0x00000000
2413
2414
2415You can check the success of the download using the 'iminfo' command;
2416this includes a checksum verification so you can be sure no data
2417corruption happened:
2418
2419 => imi 40100000
2420
2421 ## Checking Image at 40100000 ...
2422 Image Name: 2.2.13 for initrd on TQM850L
2423 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2424 Data Size: 335725 Bytes = 327 kB = 0 MB
2425 Load Address: 00000000
2426 Entry Point: 0000000c
2427 Verifying Checksum ... OK
2428
2429
2430
2431Boot Linux:
2432-----------
2433
2434The "bootm" command is used to boot an application that is stored in
2435memory (RAM or Flash). In case of a Linux kernel image, the contents
2436of the "bootargs" environment variable is passed to the kernel as
2437parameters. You can check and modify this variable using the
2438"printenv" and "setenv" commands:
2439
2440
2441 => printenv bootargs
2442 bootargs=root=/dev/ram
2443
2444 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2445
2446 => printenv bootargs
2447 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2448
2449 => bootm 40020000
2450 ## Booting Linux kernel at 40020000 ...
2451 Image Name: 2.2.13 for NFS on TQM850L
2452 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2453 Data Size: 381681 Bytes = 372 kB = 0 MB
2454 Load Address: 00000000
2455 Entry Point: 0000000c
2456 Verifying Checksum ... OK
2457 Uncompressing Kernel Image ... OK
2458 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
2459 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2460 time_init: decrementer frequency = 187500000/60
2461 Calibrating delay loop... 49.77 BogoMIPS
2462 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2463 ...
2464
2465If you want to boot a Linux kernel with initial ram disk, you pass
2466the memory addreses of both the kernel and the initrd image (PPBCOOT
2467format!) to the "bootm" command:
2468
2469 => imi 40100000 40200000
2470
2471 ## Checking Image at 40100000 ...
2472 Image Name: 2.2.13 for initrd on TQM850L
2473 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2474 Data Size: 335725 Bytes = 327 kB = 0 MB
2475 Load Address: 00000000
2476 Entry Point: 0000000c
2477 Verifying Checksum ... OK
2478
2479 ## Checking Image at 40200000 ...
2480 Image Name: Simple Ramdisk Image
2481 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2482 Data Size: 566530 Bytes = 553 kB = 0 MB
2483 Load Address: 00000000
2484 Entry Point: 00000000
2485 Verifying Checksum ... OK
2486
2487 => bootm 40100000 40200000
2488 ## Booting Linux kernel at 40100000 ...
2489 Image Name: 2.2.13 for initrd on TQM850L
2490 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2491 Data Size: 335725 Bytes = 327 kB = 0 MB
2492 Load Address: 00000000
2493 Entry Point: 0000000c
2494 Verifying Checksum ... OK
2495 Uncompressing Kernel Image ... OK
2496 ## Loading RAMDisk Image at 40200000 ...
2497 Image Name: Simple Ramdisk Image
2498 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2499 Data Size: 566530 Bytes = 553 kB = 0 MB
2500 Load Address: 00000000
2501 Entry Point: 00000000
2502 Verifying Checksum ... OK
2503 Loading Ramdisk ... OK
2504 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
2505 Boot arguments: root=/dev/ram
2506 time_init: decrementer frequency = 187500000/60
2507 Calibrating delay loop... 49.77 BogoMIPS
2508 ...
2509 RAMDISK: Compressed image found at block 0
2510 VFS: Mounted root (ext2 filesystem).
2511
2512 bash#
2513
wdenk6069ff22003-02-28 00:49:47 +00002514More About U-Boot Image Types:
2515------------------------------
2516
2517U-Boot supports the following image types:
2518
2519 "Standalone Programs" are directly runnable in the environment
2520 provided by U-Boot; it is expected that (if they behave
2521 well) you can continue to work in U-Boot after return from
2522 the Standalone Program.
2523 "OS Kernel Images" are usually images of some Embedded OS which
2524 will take over control completely. Usually these programs
2525 will install their own set of exception handlers, device
2526 drivers, set up the MMU, etc. - this means, that you cannot
2527 expect to re-enter U-Boot except by resetting the CPU.
2528 "RAMDisk Images" are more or less just data blocks, and their
2529 parameters (address, size) are passed to an OS kernel that is
2530 being started.
2531 "Multi-File Images" contain several images, typically an OS
2532 (Linux) kernel image and one or more data images like
2533 RAMDisks. This construct is useful for instance when you want
2534 to boot over the network using BOOTP etc., where the boot
2535 server provides just a single image file, but you want to get
2536 for instance an OS kernel and a RAMDisk image.
stroesec1551ea2003-04-04 15:53:41 +00002537
wdenk6069ff22003-02-28 00:49:47 +00002538 "Multi-File Images" start with a list of image sizes, each
2539 image size (in bytes) specified by an "uint32_t" in network
2540 byte order. This list is terminated by an "(uint32_t)0".
2541 Immediately after the terminating 0 follow the images, one by
2542 one, all aligned on "uint32_t" boundaries (size rounded up to
2543 a multiple of 4 bytes).
stroesec1551ea2003-04-04 15:53:41 +00002544
wdenk6069ff22003-02-28 00:49:47 +00002545 "Firmware Images" are binary images containing firmware (like
2546 U-Boot or FPGA images) which usually will be programmed to
2547 flash memory.
stroesec1551ea2003-04-04 15:53:41 +00002548
wdenk6069ff22003-02-28 00:49:47 +00002549 "Script files" are command sequences that will be executed by
2550 U-Boot's command interpreter; this feature is especially
2551 useful when you configure U-Boot to use a real shell (hush)
2552 as command interpreter.
2553
wdenkc6097192002-11-03 00:24:07 +00002554
2555Standalone HOWTO:
2556=================
2557
2558One of the features of U-Boot is that you can dynamically load and
2559run "standalone" applications, which can use some resources of
2560U-Boot like console I/O functions or interrupt services.
2561
2562Two simple examples are included with the sources:
2563
2564"Hello World" Demo:
2565-------------------
2566
2567'examples/hello_world.c' contains a small "Hello World" Demo
2568application; it is automatically compiled when you build U-Boot.
2569It's configured to run at address 0x00040004, so you can play with it
2570like that:
2571
2572 => loads
2573 ## Ready for S-Record download ...
2574 ~>examples/hello_world.srec
2575 1 2 3 4 5 6 7 8 9 10 11 ...
2576 [file transfer complete]
2577 [connected]
2578 ## Start Addr = 0x00040004
2579
2580 => go 40004 Hello World! This is a test.
2581 ## Starting application at 0x00040004 ...
2582 Hello World
2583 argc = 7
2584 argv[0] = "40004"
2585 argv[1] = "Hello"
2586 argv[2] = "World!"
2587 argv[3] = "This"
2588 argv[4] = "is"
2589 argv[5] = "a"
2590 argv[6] = "test."
2591 argv[7] = "<NULL>"
2592 Hit any key to exit ...
2593
2594 ## Application terminated, rc = 0x0
2595
2596Another example, which demonstrates how to register a CPM interrupt
2597handler with the U-Boot code, can be found in 'examples/timer.c'.
2598Here, a CPM timer is set up to generate an interrupt every second.
2599The interrupt service routine is trivial, just printing a '.'
2600character, but this is just a demo program. The application can be
2601controlled by the following keys:
2602
2603 ? - print current values og the CPM Timer registers
2604 b - enable interrupts and start timer
2605 e - stop timer and disable interrupts
2606 q - quit application
2607
2608 => loads
2609 ## Ready for S-Record download ...
2610 ~>examples/timer.srec
2611 1 2 3 4 5 6 7 8 9 10 11 ...
2612 [file transfer complete]
2613 [connected]
2614 ## Start Addr = 0x00040004
2615
2616 => go 40004
2617 ## Starting application at 0x00040004 ...
2618 TIMERS=0xfff00980
2619 Using timer 1
2620 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2621
2622Hit 'b':
2623 [q, b, e, ?] Set interval 1000000 us
2624 Enabling timer
2625Hit '?':
2626 [q, b, e, ?] ........
2627 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2628Hit '?':
2629 [q, b, e, ?] .
2630 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2631Hit '?':
2632 [q, b, e, ?] .
2633 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2634Hit '?':
2635 [q, b, e, ?] .
2636 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2637Hit 'e':
2638 [q, b, e, ?] ...Stopping timer
2639Hit 'q':
2640 [q, b, e, ?] ## Application terminated, rc = 0x0
2641
2642
wdenk85ec0bc2003-03-31 16:34:49 +00002643
2644Minicom warning:
2645================
2646
2647Over time, many people have reported problems when trying to used the
wdenkf07771c2003-05-28 08:06:31 +00002648"minicom" terminal emulation program for serial download. I (wd)
2649consider minicom to be broken, and recommend not to use it. Under
2650Unix, I recommend to use C-Kermit for general purpose use (and
wdenk85ec0bc2003-03-31 16:34:49 +00002651especially for kermit binary protocol download ("loadb" command), and
2652use "cu" for S-Record download ("loads" command).
2653
wdenk52f52c12003-06-19 23:04:19 +00002654Nevertheless, if you absolutely want to use it try adding this
2655configuration to your "File transfer protocols" section:
2656
2657 Name Program Name U/D FullScr IO-Red. Multi
2658 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2659 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2660
2661
wdenkc6097192002-11-03 00:24:07 +00002662NetBSD Notes:
2663=============
2664
2665Starting at version 0.9.2, U-Boot supports NetBSD both as host
2666(build U-Boot) and target system (boots NetBSD/mpc8xx).
2667
2668Building requires a cross environment; it is known to work on
2669NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2670need gmake since the Makefiles are not compatible with BSD make).
2671Note that the cross-powerpc package does not install include files;
2672attempting to build U-Boot will fail because <machine/ansi.h> is
2673missing. This file has to be installed and patched manually:
2674
2675 # cd /usr/pkg/cross/powerpc-netbsd/include
2676 # mkdir powerpc
2677 # ln -s powerpc machine
2678 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2679 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2680
2681Native builds *don't* work due to incompatibilities between native
2682and U-Boot include files.
2683
2684Booting assumes that (the first part of) the image booted is a
2685stage-2 loader which in turn loads and then invokes the kernel
2686proper. Loader sources will eventually appear in the NetBSD source
2687tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2688meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2689details.
2690
2691
2692Implementation Internals:
2693=========================
2694
2695The following is not intended to be a complete description of every
2696implementation detail. However, it should help to understand the
2697inner workings of U-Boot and make it easier to port it to custom
2698hardware.
2699
2700
2701Initial Stack, Global Data:
2702---------------------------
2703
2704The implementation of U-Boot is complicated by the fact that U-Boot
2705starts running out of ROM (flash memory), usually without access to
2706system RAM (because the memory controller is not initialized yet).
2707This means that we don't have writable Data or BSS segments, and BSS
2708is not initialized as zero. To be able to get a C environment working
2709at all, we have to allocate at least a minimal stack. Implementation
2710options for this are defined and restricted by the CPU used: Some CPU
2711models provide on-chip memory (like the IMMR area on MPC8xx and
2712MPC826x processors), on others (parts of) the data cache can be
2713locked as (mis-) used as memory, etc.
2714
wdenk43d96162003-03-06 00:02:04 +00002715 Chris Hallinan posted a good summy of these issues to the
2716 u-boot-users mailing list:
2717
2718 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2719 From: "Chris Hallinan" <clh@net1plus.com>
2720 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2721 ...
2722
2723 Correct me if I'm wrong, folks, but the way I understand it
2724 is this: Using DCACHE as initial RAM for Stack, etc, does not
2725 require any physical RAM backing up the cache. The cleverness
2726 is that the cache is being used as a temporary supply of
2727 necessary storage before the SDRAM controller is setup. It's
2728 beyond the scope of this list to expain the details, but you
2729 can see how this works by studying the cache architecture and
2730 operation in the architecture and processor-specific manuals.
2731
2732 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2733 is another option for the system designer to use as an
2734 initial stack/ram area prior to SDRAM being available. Either
2735 option should work for you. Using CS 4 should be fine if your
2736 board designers haven't used it for something that would
2737 cause you grief during the initial boot! It is frequently not
2738 used.
2739
2740 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2741 with your processor/board/system design. The default value
2742 you will find in any recent u-boot distribution in
2743 Walnut405.h should work for you. I'd set it to a value larger
2744 than your SDRAM module. If you have a 64MB SDRAM module, set
2745 it above 400_0000. Just make sure your board has no resources
2746 that are supposed to respond to that address! That code in
2747 start.S has been around a while and should work as is when
2748 you get the config right.
2749
2750 -Chris Hallinan
2751 DS4.COM, Inc.
2752
wdenkc6097192002-11-03 00:24:07 +00002753It is essential to remember this, since it has some impact on the C
2754code for the initialization procedures:
2755
2756* Initialized global data (data segment) is read-only. Do not attempt
2757 to write it.
2758
2759* Do not use any unitialized global data (or implicitely initialized
2760 as zero data - BSS segment) at all - this is undefined, initiali-
2761 zation is performed later (when relocationg to RAM).
2762
2763* Stack space is very limited. Avoid big data buffers or things like
2764 that.
2765
2766Having only the stack as writable memory limits means we cannot use
2767normal global data to share information beween the code. But it
2768turned out that the implementation of U-Boot can be greatly
2769simplified by making a global data structure (gd_t) available to all
2770functions. We could pass a pointer to this data as argument to _all_
2771functions, but this would bloat the code. Instead we use a feature of
2772the GCC compiler (Global Register Variables) to share the data: we
2773place a pointer (gd) to the global data into a register which we
2774reserve for this purpose.
2775
2776When chosing a register for such a purpose we are restricted by the
2777relevant (E)ABI specifications for the current architecture, and by
2778GCC's implementation.
2779
2780For PowerPC, the following registers have specific use:
2781 R1: stack pointer
2782 R2: TOC pointer
2783 R3-R4: parameter passing and return values
2784 R5-R10: parameter passing
2785 R13: small data area pointer
2786 R30: GOT pointer
2787 R31: frame pointer
2788
2789 (U-Boot also uses R14 as internal GOT pointer.)
2790
2791 ==> U-Boot will use R29 to hold a pointer to the global data
2792
2793 Note: on PPC, we could use a static initializer (since the
2794 address of the global data structure is known at compile time),
2795 but it turned out that reserving a register results in somewhat
2796 smaller code - although the code savings are not that big (on
2797 average for all boards 752 bytes for the whole U-Boot image,
2798 624 text + 127 data).
2799
2800On ARM, the following registers are used:
2801
2802 R0: function argument word/integer result
2803 R1-R3: function argument word
2804 R9: GOT pointer
2805 R10: stack limit (used only if stack checking if enabled)
2806 R11: argument (frame) pointer
2807 R12: temporary workspace
2808 R13: stack pointer
2809 R14: link register
2810 R15: program counter
2811
2812 ==> U-Boot will use R8 to hold a pointer to the global data
2813
2814
2815
2816Memory Management:
2817------------------
2818
2819U-Boot runs in system state and uses physical addresses, i.e. the
2820MMU is not used either for address mapping nor for memory protection.
2821
2822The available memory is mapped to fixed addresses using the memory
2823controller. In this process, a contiguous block is formed for each
2824memory type (Flash, SDRAM, SRAM), even when it consists of several
2825physical memory banks.
2826
2827U-Boot is installed in the first 128 kB of the first Flash bank (on
2828TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2829booting and sizing and initializing DRAM, the code relocates itself
2830to the upper end of DRAM. Immediately below the U-Boot code some
2831memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2832configuration setting]. Below that, a structure with global Board
2833Info data is placed, followed by the stack (growing downward).
2834
2835Additionally, some exception handler code is copied to the low 8 kB
2836of DRAM (0x00000000 ... 0x00001FFF).
2837
2838So a typical memory configuration with 16 MB of DRAM could look like
2839this:
2840
2841 0x0000 0000 Exception Vector code
2842 :
2843 0x0000 1FFF
2844 0x0000 2000 Free for Application Use
2845 :
2846 :
2847
2848 :
2849 :
2850 0x00FB FF20 Monitor Stack (Growing downward)
2851 0x00FB FFAC Board Info Data and permanent copy of global data
2852 0x00FC 0000 Malloc Arena
2853 :
2854 0x00FD FFFF
2855 0x00FE 0000 RAM Copy of Monitor Code
2856 ... eventually: LCD or video framebuffer
2857 ... eventually: pRAM (Protected RAM - unchanged by reset)
2858 0x00FF FFFF [End of RAM]
2859
2860
2861System Initialization:
2862----------------------
2863
2864In the reset configuration, U-Boot starts at the reset entry point
2865(on most PowerPC systens at address 0x00000100). Because of the reset
2866configuration for CS0# this is a mirror of the onboard Flash memory.
2867To be able to re-map memory U-Boot then jumps to it's link address.
2868To be able to implement the initialization code in C, a (small!)
2869initial stack is set up in the internal Dual Ported RAM (in case CPUs
2870which provide such a feature like MPC8xx or MPC8260), or in a locked
2871part of the data cache. After that, U-Boot initializes the CPU core,
2872the caches and the SIU.
2873
2874Next, all (potentially) available memory banks are mapped using a
2875preliminary mapping. For example, we put them on 512 MB boundaries
2876(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2877on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2878programmed for SDRAM access. Using the temporary configuration, a
2879simple memory test is run that determines the size of the SDRAM
2880banks.
2881
2882When there is more than one SDRAM bank, and the banks are of
2883different size, the larger is mapped first. For equal size, the first
2884bank (CS2#) is mapped first. The first mapping is always for address
28850x00000000, with any additional banks following immediately to create
2886contiguous memory starting from 0.
2887
2888Then, the monitor installs itself at the upper end of the SDRAM area
2889and allocates memory for use by malloc() and for the global Board
2890Info data; also, the exception vector code is copied to the low RAM
2891pages, and the final stack is set up.
2892
2893Only after this relocation will you have a "normal" C environment;
2894until that you are restricted in several ways, mostly because you are
2895running from ROM, and because the code will have to be relocated to a
2896new address in RAM.
2897
2898
2899U-Boot Porting Guide:
2900----------------------
2901
2902[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
wdenk6aff3112002-12-17 01:51:00 +00002903list, October 2002]
wdenkc6097192002-11-03 00:24:07 +00002904
2905
2906int main (int argc, char *argv[])
2907{
2908 sighandler_t no_more_time;
2909
2910 signal (SIGALRM, no_more_time);
2911 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2912
2913 if (available_money > available_manpower) {
2914 pay consultant to port U-Boot;
2915 return 0;
2916 }
2917
2918 Download latest U-Boot source;
2919
wdenk6aff3112002-12-17 01:51:00 +00002920 Subscribe to u-boot-users mailing list;
2921
wdenkc6097192002-11-03 00:24:07 +00002922 if (clueless) {
2923 email ("Hi, I am new to U-Boot, how do I get started?");
2924 }
2925
2926 while (learning) {
2927 Read the README file in the top level directory;
2928 Read http://www.denx.de/re/DPLG.html
2929 Read the source, Luke;
2930 }
2931
2932 if (available_money > toLocalCurrency ($2500)) {
2933 Buy a BDI2000;
2934 } else {
2935 Add a lot of aggravation and time;
2936 }
2937
2938 Create your own board support subdirectory;
2939
wdenk6aff3112002-12-17 01:51:00 +00002940 Create your own board config file;
2941
wdenkc6097192002-11-03 00:24:07 +00002942 while (!running) {
2943 do {
2944 Add / modify source code;
2945 } until (compiles);
2946 Debug;
2947 if (clueless)
2948 email ("Hi, I am having problems...");
2949 }
2950 Send patch file to Wolfgang;
2951
2952 return 0;
2953}
2954
2955void no_more_time (int sig)
2956{
2957 hire_a_guru();
2958}
2959
2960
2961
2962Coding Standards:
2963-----------------
2964
2965All contributions to U-Boot should conform to the Linux kernel
2966coding style; see the file "Documentation/CodingStyle" in your Linux
2967kernel source directory.
2968
2969Please note that U-Boot is implemented in C (and to some small parts
2970in Assembler); no C++ is used, so please do not use C++ style
2971comments (//) in your code.
2972
2973Submissions which do not conform to the standards may be returned
2974with a request to reformat the changes.
2975
2976
2977Submitting Patches:
2978-------------------
2979
2980Since the number of patches for U-Boot is growing, we need to
2981establish some rules. Submissions which do not conform to these rules
2982may be rejected, even when they contain important and valuable stuff.
2983
2984
2985When you send a patch, please include the following information with
2986it:
2987
2988* For bug fixes: a description of the bug and how your patch fixes
2989 this bug. Please try to include a way of demonstrating that the
2990 patch actually fixes something.
2991
2992* For new features: a description of the feature and your
2993 implementation.
2994
2995* A CHANGELOG entry as plaintext (separate from the patch)
2996
2997* For major contributions, your entry to the CREDITS file
2998
2999* When you add support for a new board, don't forget to add this
3000 board to the MAKEALL script, too.
3001
3002* If your patch adds new configuration options, don't forget to
3003 document these in the README file.
3004
3005* The patch itself. If you are accessing the CVS repository use "cvs
3006 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3007 version of diff does not support these options, then get the latest
3008 version of GNU diff.
3009
3010 We accept patches as plain text, MIME attachments or as uuencoded
3011 gzipped text.
3012
wdenk52f52c12003-06-19 23:04:19 +00003013* If one logical set of modifications affects or creates several
3014 files, all these changes shall be submitted in a SINGLE patch file.
3015
3016* Changesets that contain different, unrelated modifications shall be
3017 submitted as SEPARATE patches, one patch per changeset.
3018
3019
wdenkc6097192002-11-03 00:24:07 +00003020Notes:
3021
3022* Before sending the patch, run the MAKEALL script on your patched
3023 source tree and make sure that no errors or warnings are reported
3024 for any of the boards.
3025
3026* Keep your modifications to the necessary minimum: A patch
3027 containing several unrelated changes or arbitrary reformats will be
3028 returned with a request to re-formatting / split it.
3029
3030* If you modify existing code, make sure that your new code does not
3031 add to the memory footprint of the code ;-) Small is beautiful!
3032 When adding new features, these should compile conditionally only
3033 (using #ifdef), and the resulting code with the new feature
3034 disabled must not need more memory than the old code without your
3035 modification.