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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
107Directory Hierarchy:
108====================
109
110- board Board dependend files
111- common Misc architecture independend functions
112- cpu CPU specific files
113- disk Code for disk drive partition handling
114- doc Documentation (don't expect too much)
115- drivers Common used device drivers
116- dtt Digital Thermometer and Thermostat drivers
117- examples Example code for standalone applications, etc.
118- include Header Files
119- disk Harddisk interface code
120- net Networking code
121- ppc Files generic to PowerPC architecture
122- post Power On Self Test
123- post/arch Symlink to architecture specific Power On Self Test
124- post/arch-ppc PowerPC architecture specific Power On Self Test
125- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
126- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
127- rtc Real Time Clock drivers
128- tools Tools to build S-Record or U-Boot images, etc.
129
130- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
131- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
132- cpu/mpc824x Files specific to Motorola MPC824x CPUs
133- cpu/mpc8260 Files specific to Motorola MPC8260 CPU
134- cpu/ppc4xx Files specific to IBM 4xx CPUs
135
136- board/RPXClassic
137 Files specific to RPXClassic boards
138- board/RPXlite Files specific to RPXlite boards
139- board/c2mon Files specific to c2mon boards
140- board/cogent Files specific to Cogent boards
141 (need further configuration)
142 Files specific to CPCIISER4 boards
143- board/cpu86 Files specific to CPU86 boards
144- board/cray/ Files specific to boards manufactured by Cray
145- board/cray/L1 Files specific to L1 boards
146- board/cu824 Files specific to CU824 boards
147- board/ebony Files specific to IBM Ebony board
148- board/eric Files specific to ERIC boards
149- board/esd/ Files specific to boards manufactured by ESD
150- board/esd/adciop Files specific to ADCIOP boards
151- board/esd/ar405 Files specific to AR405 boards
152- board/esd/canbt Files specific to CANBT boards
153- board/esd/cpci405 Files specific to CPCI405 boards
154- board/esd/cpciiser4 Files specific to CPCIISER4 boards
155- board/esd/common Common files for ESD boards
156- board/esd/dasa_sim Files specific to DASA_SIM boards
157- board/esd/du405 Files specific to DU405 boards
158- board/esd/ocrtc Files specific to OCRTC boards
159- board/esd/pci405 Files specific to PCI405 boards
160- board/esteem192e
161 Files specific to ESTEEM192E boards
162- board/etx094 Files specific to ETX_094 boards
163- board/evb64260
164 Files specific to EVB64260 boards
165- board/fads Files specific to FADS boards
166- board/flagadm Files specific to FLAGADM boards
167- board/gen860t Files specific to GEN860T boards
168- board/genietv Files specific to GENIETV boards
169- board/gth Files specific to GTH boards
170- board/hermes Files specific to HERMES boards
171- board/hymod Files specific to HYMOD boards
172- board/icu862 Files specific to ICU862 boards
173- board/ip860 Files specific to IP860 boards
174- board/iphase4539
175 Files specific to Interphase4539 boards
176- board/ivm Files specific to IVMS8/IVML24 boards
177- board/lantec Files specific to LANTEC boards
178- board/lwmon Files specific to LWMON boards
179- board/mbx8xx Files specific to MBX boards
180- board/mpc8260ads
181 Files specific to MMPC8260ADS boards
182- board/mpl/ Files specific to boards manufactured by MPL
183- board/mpl/common Common files for MPL boards
184- board/mpl/pip405 Files specific to PIP405 boards
185- board/mpl/mip405 Files specific to MIP405 boards
186- board/musenki Files specific to MUSEKNI boards
187- board/mvs1 Files specific to MVS1 boards
188- board/nx823 Files specific to NX823 boards
189- board/oxc Files specific to OXC boards
190- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
191- board/pm826 Files specific to PM826 boards
192- board/ppmc8260
193 Files specific to PPMC8260 boards
194- board/rpxsuper
195 Files specific to RPXsuper boards
196- board/rsdproto
197 Files specific to RSDproto boards
198- board/sandpoint
199 Files specific to Sandpoint boards
200- board/sbc8260 Files specific to SBC8260 boards
201- board/sacsng Files specific to SACSng boards
202- board/siemens Files specific to boards manufactured by Siemens AG
203- board/siemens/CCM Files specific to CCM boards
204- board/siemens/IAD210 Files specific to IAD210 boards
205- board/siemens/SCM Files specific to SCM boards
206- board/siemens/pcu_e Files specific to PCU_E boards
207- board/sixnet Files specific to SIXNET boards
208- board/spd8xx Files specific to SPD8xxTS boards
209- board/tqm8260 Files specific to TQM8260 boards
210- board/tqm8xx Files specific to TQM8xxL boards
211- board/w7o Files specific to W7O boards
212- board/walnut405
213 Files specific to Walnut405 boards
214- board/westel/ Files specific to boards manufactured by Westel Wireless
215- board/westel/amx860 Files specific to AMX860 boards
216- board/utx8245 Files specific to UTX8245 boards
217
218Software Configuration:
219=======================
220
221Configuration is usually done using C preprocessor defines; the
222rationale behind that is to avoid dead code whenever possible.
223
224There are two classes of configuration variables:
225
226* Configuration _OPTIONS_:
227 These are selectable by the user and have names beginning with
228 "CONFIG_".
229
230* Configuration _SETTINGS_:
231 These depend on the hardware etc. and should not be meddled with if
232 you don't know what you're doing; they have names beginning with
233 "CFG_".
234
235Later we will add a configuration tool - probably similar to or even
236identical to what's used for the Linux kernel. Right now, we have to
237do the configuration by hand, which means creating some symbolic
238links and editing some configuration files. We use the TQM8xxL boards
239as an example here.
240
241
242Selection of Processor Architecture and Board Type:
243---------------------------------------------------
244
245For all supported boards there are ready-to-use default
246configurations available; just type "make <board_name>_config".
247
248Example: For a TQM823L module type:
249
250 cd u-boot
251 make TQM823L_config
252
253For the Cogent platform, you need to specify the cpu type as well;
254e.g. "make cogent_mpc8xx_config". And also configure the cogent
255directory according to the instructions in cogent/README.
256
257
258Configuration Options:
259----------------------
260
261Configuration depends on the combination of board and CPU type; all
262such information is kept in a configuration file
263"include/configs/<board_name>.h".
264
265Example: For a TQM823L module, all configuration settings are in
266"include/configs/TQM823L.h".
267
268
wdenk7f6c2cb2002-11-10 22:06:23 +0000269Many of the options are named exactly as the corresponding Linux
270kernel configuration options. The intention is to make it easier to
271build a config tool - later.
272
273
wdenkc6097192002-11-03 00:24:07 +0000274The following options need to be configured:
275
276- CPU Type: Define exactly one of
277
278 PowerPC based CPUs:
279 -------------------
280 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
281 or CONFIG_MPC824X, CONFIG_MPC8260
282 or CONFIG_IOP480
283 or CONFIG_405GP
284 or CONFIG_440
285 or CONFIG_MPC74xx
286
287 ARM based CPUs:
288 ---------------
289 CONFIG_SA1110
290 CONFIG_ARM7
291 CONFIG_PXA250
292
293
294- Board Type: Define exactly one of
295
296 PowerPC based boards:
297 ---------------------
298
299 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
300 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
301 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
302 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
303 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
304 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
305 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
306 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
307 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
308 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
309 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
310 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
311 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
312 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
313 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
314 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
315 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
316 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
317 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
318 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
319 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
320 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
321 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
322 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
323 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
324 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
325 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
326 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
327 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
wdenk384ae022002-11-05 00:17:55 +0000328 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L
wdenkc6097192002-11-03 00:24:07 +0000329
330 ARM based boards:
331 -----------------
332
333 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
334 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
335 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
336 CONFIG_TRAB
337
338
339- CPU Module Type: (if CONFIG_COGENT is defined)
340 Define exactly one of
341 CONFIG_CMA286_60_OLD
342--- FIXME --- not tested yet:
343 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
344 CONFIG_CMA287_23, CONFIG_CMA287_50
345
346- Motherboard Type: (if CONFIG_COGENT is defined)
347 Define exactly one of
348 CONFIG_CMA101, CONFIG_CMA102
349
350- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
351 Define one or more of
352 CONFIG_CMA302
353
354- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
355 Define one or more of
356 CONFIG_LCD_HEARTBEAT - update a character position on
357 the lcd display every second with
358 a "rotator" |\-/|\-/
359
360- MPC824X Family Member (if CONFIG_MPC824X is defined)
361 Define exactly one of
362 CONFIG_MPC8240, CONFIG_MPC8245
363
364- 8xx CPU Options: (if using an 8xx cpu)
365 Define one or more of
366 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
367 no 32KHz reference PIT/RTC clock
368
369- Clock Interface:
370 CONFIG_CLOCKS_IN_MHZ
371
372 U-Boot stores all clock information in Hz
373 internally. For binary compatibility with older Linux
374 kernels (which expect the clocks passed in the
375 bd_info data to be in MHz) the environment variable
376 "clocks_in_mhz" can be defined so that U-Boot
377 converts clock data to MHZ before passing it to the
378 Linux kernel.
379
380 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
381 "clocks_in_mhz=1" is automatically included in the
382 default environment.
383
384- Console Interface:
385 Depending on board, define exactly one serial port
386 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
387 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
388 console by defining CONFIG_8xx_CONS_NONE
389
390 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
391 port routines must be defined elsewhere
392 (i.e. serial_init(), serial_getc(), ...)
393
394 CONFIG_CFB_CONSOLE
395 Enables console device for a color framebuffer. Needs following
396 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
397 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
398 (default big endian)
399 VIDEO_HW_RECTFILL graphic chip supports
400 rectangle fill
401 (cf. smiLynxEM)
402 VIDEO_HW_BITBLT graphic chip supports
403 bit-blit (cf. smiLynxEM)
404 VIDEO_VISIBLE_COLS visible pixel columns
405 (cols=pitch)
406 VIDEO_VISIBLE_ROWS visible pixel rows
407 VIDEO_PIXEL_SIZE bytes per pixel
408 VIDEO_DATA_FORMAT graphic data format
409 (0-5, cf. cfb_console.c)
410 VIDEO_FB_ADRS framebuffer address
411 VIDEO_KBD_INIT_FCT keyboard int fct
412 (i.e. i8042_kbd_init())
413 VIDEO_TSTC_FCT test char fct
414 (i.e. i8042_tstc)
415 VIDEO_GETC_FCT get char fct
416 (i.e. i8042_getc)
417 CONFIG_CONSOLE_CURSOR cursor drawing on/off
418 (requires blink timer
419 cf. i8042.c)
420 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
421 CONFIG_CONSOLE_TIME display time/date info in
422 upper right corner
423 (requires CFG_CMD_DATE)
424 CONFIG_VIDEO_LOGO display Linux logo in
425 upper left corner
426 CONFIG_CONSOLE_EXTRA_INFO
427 addional board info beside
428 the logo
429
430 When CONFIG_CFB_CONSOLE is defined, video console is
431 default i/o. Serial console can be forced with
432 environment 'console=serial'.
433
434- Console Baudrate:
435 CONFIG_BAUDRATE - in bps
436 Select one of the baudrates listed in
437 CFG_BAUDRATE_TABLE, see below.
438
439- Interrupt driven serial port input:
440 CONFIG_SERIAL_SOFTWARE_FIFO
441
442 PPC405GP only.
443 Use an interrupt handler for receiving data on the
444 serial port. It also enables using hardware handshake
445 (RTS/CTS) and UART's built-in FIFO. Set the number of
446 bytes the interrupt driven input buffer should have.
447
448 Set to 0 to disable this feature (this is the default).
449 This will also disable hardware handshake.
450
451- Boot Delay: CONFIG_BOOTDELAY - in seconds
452 Delay before automatically booting the default image;
453 set to -1 to disable autoboot.
454
455 See doc/README.autoboot for these options that
456 work with CONFIG_BOOTDELAY. None are required.
457 CONFIG_BOOT_RETRY_TIME
458 CONFIG_BOOT_RETRY_MIN
459 CONFIG_AUTOBOOT_KEYED
460 CONFIG_AUTOBOOT_PROMPT
461 CONFIG_AUTOBOOT_DELAY_STR
462 CONFIG_AUTOBOOT_STOP_STR
463 CONFIG_AUTOBOOT_DELAY_STR2
464 CONFIG_AUTOBOOT_STOP_STR2
465 CONFIG_ZERO_BOOTDELAY_CHECK
466 CONFIG_RESET_TO_RETRY
467
468- Autoboot Command:
469 CONFIG_BOOTCOMMAND
470 Only needed when CONFIG_BOOTDELAY is enabled;
471 define a command string that is automatically executed
472 when no character is read on the console interface
473 within "Boot Delay" after reset.
474
475 CONFIG_BOOTARGS
476 This can be used to pass arguments to the bootm
477 command. The value of CONFIG_BOOTARGS goes into the
478 environment value "bootargs".
479
480 CONFIG_RAMBOOT and CONFIG_NFSBOOT
481 The value of these goes into the environment as
482 "ramboot" and "nfsboot" respectively, and can be used
483 as a convenience, when switching between booting from
484 ram and nfs.
485
486- Pre-Boot Commands:
487 CONFIG_PREBOOT
488
489 When this option is #defined, the existence of the
490 environment variable "preboot" will be checked
491 immediately before starting the CONFIG_BOOTDELAY
492 countdown and/or running the auto-boot command resp.
493 entering interactive mode.
494
495 This feature is especially useful when "preboot" is
496 automatically generated or modified. For an example
497 see the LWMON board specific code: here "preboot" is
498 modified when the user holds down a certain
499 combination of keys on the (special) keyboard when
500 booting the systems
501
502- Serial Download Echo Mode:
503 CONFIG_LOADS_ECHO
504 If defined to 1, all characters received during a
505 serial download (using the "loads" command) are
506 echoed back. This might be needed by some terminal
507 emulations (like "cu"), but may as well just take
508 time on others. This setting #define's the initial
509 value of the "loads_echo" environment variable.
510
511- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
512 CONFIG_KGDB_BAUDRATE
513 Select one of the baudrates listed in
514 CFG_BAUDRATE_TABLE, see below.
515
516- Monitor Functions:
517 CONFIG_COMMANDS
518 Most monitor functions can be selected (or
519 de-selected) by adjusting the definition of
520 CONFIG_COMMANDS; to select individual functions,
521 #define CONFIG_COMMANDS by "OR"ing any of the
522 following values:
523
524 #define enables commands:
525 -------------------------
526 CFG_CMD_ASKENV * ask for env variable
527 CFG_CMD_BDI bdinfo
528 CFG_CMD_BEDBUG Include BedBug Debugger
529 CFG_CMD_BOOTD bootd
530 CFG_CMD_CACHE icache, dcache
531 CFG_CMD_CONSOLE coninfo
532 CFG_CMD_DATE * support for RTC, date/time...
533 CFG_CMD_DHCP DHCP support
534 CFG_CMD_ECHO * echo arguments
535 CFG_CMD_EEPROM * EEPROM read/write support
536 CFG_CMD_ELF bootelf, bootvx
537 CFG_CMD_ENV saveenv
538 CFG_CMD_FDC * Floppy Disk Support
wdenk2262cfe2002-11-18 00:14:45 +0000539 CFG_CMD_FDOS * Dos diskette Support
wdenkc6097192002-11-03 00:24:07 +0000540 CFG_CMD_FLASH flinfo, erase, protect
541 CFG_CMD_FPGA FPGA device initialization support
542 CFG_CMD_I2C * I2C serial bus support
543 CFG_CMD_IDE * IDE harddisk support
544 CFG_CMD_IMI iminfo
545 CFG_CMD_IMMAP * IMMR dump support
546 CFG_CMD_IRQ * irqinfo
547 CFG_CMD_KGDB * kgdb
548 CFG_CMD_LOADB loadb
549 CFG_CMD_LOADS loads
550 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
551 loop, mtest
552 CFG_CMD_MII MII utility commands
553 CFG_CMD_NET bootp, tftpboot, rarpboot
554 CFG_CMD_PCI * pciinfo
555 CFG_CMD_PCMCIA * PCMCIA support
556 CFG_CMD_REGINFO * Register dump
557 CFG_CMD_RUN run command in env variable
558 CFG_CMD_SCSI * SCSI Support
559 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
560 CFG_CMD_SPI * SPI serial bus support
561 CFG_CMD_USB * USB support
562 CFG_CMD_BSP * Board SPecific functions
563 -----------------------------------------------
564 CFG_CMD_ALL all
565
566 CFG_CMD_DFL Default configuration; at the moment
567 this is includes all commands, except
568 the ones marked with "*" in the list
569 above.
570
571 If you don't define CONFIG_COMMANDS it defaults to
572 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
573 override the default settings in the respective
574 include file.
575
576 EXAMPLE: If you want all functions except of network
577 support you can write:
578
579 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
580
581
582 Note: Don't enable the "icache" and "dcache" commands
583 (configuration option CFG_CMD_CACHE) unless you know
584 what you (and your U-Boot users) are doing. Data
585 cache cannot be enabled on systems like the 8xx or
586 8260 (where accesses to the IMMR region must be
587 uncached), and it cannot be disabled on all other
588 systems where we (mis-) use the data cache to hold an
589 initial stack and some data.
590
591
592 XXX - this list needs to get updated!
593
594- Watchdog:
595 CONFIG_WATCHDOG
596 If this variable is defined, it enables watchdog
597 support. There must support in the platform specific
598 code for a watchdog. For the 8xx and 8260 CPUs, the
599 SIU Watchdog feature is enabled in the SYPCR
600 register.
601
602- Real-Time Clock:
603
604 When CFG_CMD_DATE is selected, the type of the RTC
605 has to be selected, too. Define exactly one of the
606 following options:
607
608 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
609 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
610 CONFIG_RTC_MC146818 - use MC146818 RTC
611 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
612
613- Timestamp Support:
614
615 When CONFIG_TIMESTAMP is selected, the timestamp
616 (date and time) of an image is printed by image
617 commands like bootm or iminfo. This option is
618 automatically enabled when you select CFG_CMD_DATE .
619
620- Partition Support:
621 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
622 and/or CONFIG_ISO_PARTITION
623
624 If IDE or SCSI support is enabled (CFG_CMD_IDE or
625 CFG_CMD_SCSI) you must configure support for at least
626 one partition type as well.
627
628- IDE Reset method:
629 CONFIG_IDE_RESET_ROUTINE
630
631 Set this to define that instead of a reset Pin, the
632 routine ide_set_reset(int idereset) will be used.
633
634- ATAPI Support:
635 CONFIG_ATAPI
636
637 Set this to enable ATAPI support.
638
639- SCSI Support:
640 At the moment only there is only support for the
641 SYM53C8XX SCSI controller; define
642 CONFIG_SCSI_SYM53C8XX to enable it.
643
644 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
645 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
646 CFG_SCSI_MAX_LUN] can be adjusted to define the
647 maximum numbers of LUNs, SCSI ID's and target
648 devices.
649 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
650
651- NETWORK Support (PCI):
652 CONFIG_EEPRO100
653 Support for Intel 82557/82559/82559ER chips.
654 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
655 write routine for first time initialisation.
656
657 CONFIG_TULIP
658 Support for Digital 2114x chips.
659 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
660 modem chip initialisation (KS8761/QS6611).
661
662 CONFIG_NATSEMI
663 Support for National dp83815 chips.
664
665 CONFIG_NS8382X
666 Support for National dp8382[01] gigabit chips.
667
668- USB Support:
669 At the moment only the UHCI host controller is
670 supported (PIP405, MIP405); define
671 CONFIG_USB_UHCI to enable it.
672 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
673 end define CONFIG_USB_STORAGE to enable the USB
674 storage devices.
675 Note:
676 Supported are USB Keyboards and USB Floppy drives
677 (TEAC FD-05PUB).
678
679- Keyboard Support:
680 CONFIG_ISA_KEYBOARD
681
682 Define this to enable standard (PC-Style) keyboard
683 support
684
685 CONFIG_I8042_KBD
686 Standard PC keyboard driver with US (is default) and
687 GERMAN key layout (switch via environment 'keymap=de') support.
688 Export function i8042_kbd_init, i8042_tstc and i8042_getc
689 for cfb_console. Supports cursor blinking.
690
691- Video support:
692 CONFIG_VIDEO
693
694 Define this to enable video support (for output to
695 video).
696
697 CONFIG_VIDEO_CT69000
698
699 Enable Chips & Technologies 69000 Video chip
700
701 CONFIG_VIDEO_SMI_LYNXEM
702 Enable Silicon Motion SMI 712/710/810 Video chip
703 Videomode are selected via environment 'videomode' with
704 standard LiLo mode numbers.
705 Following modes are supported (* is default):
706
707 800x600 1024x768 1280x1024
708 256 (8bit) 303* 305 307
709 65536 (16bit) 314 317 31a
710 16,7 Mill (24bit) 315 318 31b
711 (i.e. setenv videomode 317; saveenv; reset;)
712
713- LCD Support: CONFIG_LCD
714
715 Define this to enable LCD support (for output to LCD
716 display); also select one of the supported displays
717 by defining one of these:
718
719 CONFIG_NEC_NL6648AC33:
720
721 NEC NL6648AC33-18. Active, color, single scan.
722
723 CONFIG_NEC_NL6648BC20
724
725 NEC NL6648BC20-08. 6.5", 640x480.
726 Active, color, single scan.
727
728 CONFIG_SHARP_16x9
729
730 Sharp 320x240. Active, color, single scan.
731 It isn't 16x9, and I am not sure what it is.
732
733 CONFIG_SHARP_LQ64D341
734
735 Sharp LQ64D341 display, 640x480.
736 Active, color, single scan.
737
738 CONFIG_HLD1045
739
740 HLD1045 display, 640x480.
741 Active, color, single scan.
742
743 CONFIG_OPTREX_BW
744
745 Optrex CBL50840-2 NF-FW 99 22 M5
746 or
747 Hitachi LMG6912RPFC-00T
748 or
749 Hitachi SP14Q002
750
751 320x240. Black & white.
752
753 Normally display is black on white background; define
754 CFG_WHITE_ON_BLACK to get it inverted.
755
756- Ethernet address:
757 CONFIG_ETHADDR
758 CONFIG_ETH2ADDR
759 CONFIG_ETH3ADDR
760
761 Define a default value for ethernet address to use
762 for the respective ethernet interface, in case this
763 is not determined automatically.
764
765- IP address:
766 CONFIG_IPADDR
767
768 Define a default value for the IP address to use for
769 the default ethernet interface, in case this is not
770 determined through e.g. bootp.
771
772- Server IP address:
773 CONFIG_SERVERIP
774
775 Defines a default value for theIP address of a TFTP
776 server to contact when using the "tftboot" command.
777
778- BOOTP Recovery Mode:
779 CONFIG_BOOTP_RANDOM_DELAY
780
781 If you have many targets in a network that try to
782 boot using BOOTP, you may want to avoid that all
783 systems send out BOOTP requests at precisely the same
784 moment (which would happen for instance at recovery
785 from a power failure, when all systems will try to
786 boot, thus flooding the BOOTP server. Defining
787 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
788 inserted before sending out BOOTP requests. The
789 following delays are insterted then:
790
791 1st BOOTP request: delay 0 ... 1 sec
792 2nd BOOTP request: delay 0 ... 2 sec
793 3rd BOOTP request: delay 0 ... 4 sec
794 4th and following
795 BOOTP requests: delay 0 ... 8 sec
796
797- Status LED: CONFIG_STATUS_LED
798
799 Several configurations allow to display the current
800 status using a LED. For instance, the LED will blink
801 fast while running U-Boot code, stop blinking as
802 soon as a reply to a BOOTP request was received, and
803 start blinking slow once the Linux kernel is running
804 (supported by a status LED driver in the Linux
805 kernel). Defining CONFIG_STATUS_LED enables this
806 feature in U-Boot.
807
808- CAN Support: CONFIG_CAN_DRIVER
809
810 Defining CONFIG_CAN_DRIVER enables CAN driver support
811 on those systems that support this (optional)
812 feature, like the TQM8xxL modules.
813
814- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
815
816 Enables I2C serial bus commands. If this is selected,
817 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
818 to include the appropriate I2C driver.
819
820 See also: common/cmd_i2c.c for a description of the
821 command line interface.
822
823
824 CONFIG_HARD_I2C
825
826 Selects the CPM hardware driver for I2C.
827
828 CONFIG_SOFT_I2C
829
830 Use software (aka bit-banging) driver instead of CPM
831 or similar hardware support for I2C. This is configured
832 via the following defines.
833
834 I2C_INIT
835
836 (Optional). Any commands necessary to enable I2C
837 controller or configure ports.
838
839 I2C_PORT
840
841 (Only for MPC8260 CPU). The I/O port to use (the code
842 assumes both bits are on the same port). Valid values
843 are 0..3 for ports A..D.
844
845 I2C_ACTIVE
846
847 The code necessary to make the I2C data line active
848 (driven). If the data line is open collector, this
849 define can be null.
850
851 I2C_TRISTATE
852
853 The code necessary to make the I2C data line tri-stated
854 (inactive). If the data line is open collector, this
855 define can be null.
856
857 I2C_READ
858
859 Code that returns TRUE if the I2C data line is high,
860 FALSE if it is low.
861
862 I2C_SDA(bit)
863
864 If <bit> is TRUE, sets the I2C data line high. If it
865 is FALSE, it clears it (low).
866
867 I2C_SCL(bit)
868
869 If <bit> is TRUE, sets the I2C clock line high. If it
870 is FALSE, it clears it (low).
871
872 I2C_DELAY
873
874 This delay is invoked four times per clock cycle so this
875 controls the rate of data transfer. The data rate thus
876 is 1 / (I2C_DELAY * 4).
877
878- SPI Support: CONFIG_SPI
879
880 Enables SPI driver (so far only tested with
881 SPI EEPROM, also an instance works with Crystal A/D and
882 D/As on the SACSng board)
883
884 CONFIG_SPI_X
885
886 Enables extended (16-bit) SPI EEPROM addressing.
887 (symmetrical to CONFIG_I2C_X)
888
889 CONFIG_SOFT_SPI
890
891 Enables a software (bit-bang) SPI driver rather than
892 using hardware support. This is a general purpose
893 driver that only requires three general I/O port pins
894 (two outputs, one input) to function. If this is
895 defined, the board configuration must define several
896 SPI configuration items (port pins to use, etc). For
897 an example, see include/configs/sacsng.h.
898
899- FPGA Support: CONFIG_FPGA_COUNT
900
901 Specify the number of FPGA devices to support.
902
903 CONFIG_FPGA
904
905 Used to specify the types of FPGA devices. For
906 example,
907 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
908
909 CFG_FPGA_PROG_FEEDBACK
910
911 Enable printing of hash marks during FPGA
912 configuration.
913
914 CFG_FPGA_CHECK_BUSY
915
916 Enable checks on FPGA configuration interface busy
917 status by the configuration function. This option
918 will require a board or device specific function to
919 be written.
920
921 CONFIG_FPGA_DELAY
922
923 If defined, a function that provides delays in the
924 FPGA configuration driver.
925
926 CFG_FPGA_CHECK_CTRLC
927
928 Allow Control-C to interrupt FPGA configuration
929
930 CFG_FPGA_CHECK_ERROR
931
932 Check for configuration errors during FPGA bitfile
933 loading. For example, abort during Virtex II
934 configuration if the INIT_B line goes low (which
935 indicated a CRC error).
936
937 CFG_FPGA_WAIT_INIT
938
939 Maximum time to wait for the INIT_B line to deassert
940 after PROB_B has been deasserted during a Virtex II
941 FPGA configuration sequence. The default time is 500 mS.
942
943 CFG_FPGA_WAIT_BUSY
944
945 Maximum time to wait for BUSY to deassert during
946 Virtex II FPGA configuration. The default is 5 mS.
947
948 CFG_FPGA_WAIT_CONFIG
949
950 Time to wait after FPGA configuration. The default is
951 200 mS.
952
953- FPGA Support: CONFIG_FPGA_COUNT
954
955 Specify the number of FPGA devices to support.
956
957 CONFIG_FPGA
958
959 Used to specify the types of FPGA devices. For example,
960 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
961
962 CFG_FPGA_PROG_FEEDBACK
963
964 Enable printing of hash marks during FPGA configuration.
965
966 CFG_FPGA_CHECK_BUSY
967
968 Enable checks on FPGA configuration interface busy
969 status by the configuration function. This option
970 will require a board or device specific function to
971 be written.
972
973 CONFIG_FPGA_DELAY
974
975 If defined, a function that provides delays in the FPGA
976 configuration driver.
977
978 CFG_FPGA_CHECK_CTRLC
979 Allow Control-C to interrupt FPGA configuration
980
981 CFG_FPGA_CHECK_ERROR
982
983 Check for configuration errors during FPGA bitfile
984 loading. For example, abort during Virtex II
985 configuration if the INIT_B line goes low (which
986 indicated a CRC error).
987
988 CFG_FPGA_WAIT_INIT
989
990 Maximum time to wait for the INIT_B line to deassert
991 after PROB_B has been deasserted during a Virtex II
992 FPGA configuration sequence. The default time is 500
993 mS.
994
995 CFG_FPGA_WAIT_BUSY
996
997 Maximum time to wait for BUSY to deassert during
998 Virtex II FPGA configuration. The default is 5 mS.
999
1000 CFG_FPGA_WAIT_CONFIG
1001
1002 Time to wait after FPGA configuration. The default is
1003 200 mS.
1004
1005- Configuration Management:
1006 CONFIG_IDENT_STRING
1007
1008 If defined, this string will be added to the U-Boot
1009 version information (U_BOOT_VERSION)
1010
1011- Vendor Parameter Protection:
1012
1013 U-Boot considers the values of the environment
1014 variables "serial#" (Board Serial Number) and
1015 "ethaddr" (Ethernet Address) to bb parameters that
1016 are set once by the board vendor / manufacturer, and
1017 protects these variables from casual modification by
1018 the user. Once set, these variables are read-only,
1019 and write or delete attempts are rejected. You can
1020 change this behviour:
1021
1022 If CONFIG_ENV_OVERWRITE is #defined in your config
1023 file, the write protection for vendor parameters is
1024 completely disabled. Anybody can change or delte
1025 these parameters.
1026
1027 Alternatively, if you #define _both_ CONFIG_ETHADDR
1028 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1029 ethernet address is installed in the environment,
1030 which can be changed exactly ONCE by the user. [The
1031 serial# is unaffected by this, i. e. it remains
1032 read-only.]
1033
1034- Protected RAM:
1035 CONFIG_PRAM
1036
1037 Define this variable to enable the reservation of
1038 "protected RAM", i. e. RAM which is not overwritten
1039 by U-Boot. Define CONFIG_PRAM to hold the number of
1040 kB you want to reserve for pRAM. You can overwrite
1041 this default value by defining an environment
1042 variable "pram" to the number of kB you want to
1043 reserve. Note that the board info structure will
1044 still show the full amount of RAM. If pRAM is
1045 reserved, a new environment variable "mem" will
1046 automatically be defined to hold the amount of
1047 remaining RAM in a form that can be passed as boot
1048 argument to Linux, for instance like that:
1049
1050 setenv bootargs ... mem=\$(mem)
1051 saveenv
1052
1053 This way you can tell Linux not to use this memory,
1054 either, which results in a memory region that will
1055 not be affected by reboots.
1056
1057 *WARNING* If your board configuration uses automatic
1058 detection of the RAM size, you must make sure that
1059 this memory test is non-destructive. So far, the
1060 following board configurations are known to be
1061 "pRAM-clean":
1062
1063 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1064 HERMES, IP860, RPXlite, LWMON, LANTEC,
1065 PCU_E, FLAGADM, TQM8260
1066
1067- Error Recovery:
1068 CONFIG_PANIC_HANG
1069
1070 Define this variable to stop the system in case of a
1071 fatal error, so that you have to reset it manually.
1072 This is probably NOT a good idea for an embedded
1073 system where you want to system to reboot
1074 automatically as fast as possible, but it may be
1075 useful during development since you can try to debug
1076 the conditions that lead to the situation.
1077
1078 CONFIG_NET_RETRY_COUNT
1079
1080 This variable defines the number of retries for
1081 network operations like ARP, RARP, TFTP, or BOOTP
1082 before giving up the operation. If not defined, a
1083 default value of 5 is used.
1084
1085- Command Interpreter:
1086 CFG_HUSH_PARSER
1087
1088 Define this variable to enable the "hush" shell (from
1089 Busybox) as command line interpreter, thus enabling
1090 powerful command line syntax like
1091 if...then...else...fi conditionals or `&&' and '||'
1092 constructs ("shell scripts").
1093
1094 If undefined, you get the old, much simpler behaviour
1095 with a somewhat smaller memory footprint.
1096
1097
1098 CFG_PROMPT_HUSH_PS2
1099
1100 This defines the secondary prompt string, which is
1101 printed when the command interpreter needs more input
1102 to complete a command. Usually "> ".
1103
1104 Note:
1105
1106 In the current implementation, the local variables
1107 space and global environment variables space are
1108 separated. Local variables are those you define by
1109 simply typing like `name=value'. To access a local
1110 variable later on, you have write `$name' or
1111 `${name}'; variable directly by typing say `$name' at
1112 the command prompt.
1113
1114 Global environment variables are those you use
1115 setenv/printenv to work with. To run a command stored
1116 in such a variable, you need to use the run command,
1117 and you must not use the '$' sign to access them.
1118
1119 To store commands and special characters in a
1120 variable, please use double quotation marks
1121 surrounding the whole text of the variable, instead
1122 of the backslashes before semicolons and special
1123 symbols.
1124
1125- Default Environment
1126 CONFIG_EXTRA_ENV_SETTINGS
1127
1128 Define this to contain any number of null terminated
1129 strings (variable = value pairs) that will be part of
1130 the default enviroment compiled into the boot image.
wdenk2262cfe2002-11-18 00:14:45 +00001131
wdenkc6097192002-11-03 00:24:07 +00001132 For example, place something like this in your
1133 board's config file:
1134
1135 #define CONFIG_EXTRA_ENV_SETTINGS \
1136 "myvar1=value1\0" \
1137 "myvar2=value2\0"
1138
1139 Warning: This method is based on knowledge about the
1140 internal format how the environment is stored by the
wdenk2262cfe2002-11-18 00:14:45 +00001141 U-Boot code. This is NOT an official, exported
wdenkc6097192002-11-03 00:24:07 +00001142 interface! Although it is unlikely that this format
wdenk2262cfe2002-11-18 00:14:45 +00001143 will change soon, but there is no guarantee either.
wdenkc6097192002-11-03 00:24:07 +00001144 You better know what you are doing here.
1145
1146 Note: overly (ab)use of the default environment is
1147 discouraged. Make sure to check other ways to preset
1148 the environment like the autoscript function or the
1149 boot command first.
1150
1151- Show boot progress
1152 CONFIG_SHOW_BOOT_PROGRESS
1153
1154 Defining this option allows to add some board-
1155 specific code (calling a user-provided function
1156 "show_boot_progress(int)") that enables you to show
1157 the system's boot progress on some display (for
1158 example, some LED's) on your board. At the moment,
1159 the following checkpoints are implemented:
1160
1161 Arg Where When
1162 1 common/cmd_bootm.c before attempting to boot an image
1163 -1 common/cmd_bootm.c Image header has bad magic number
1164 2 common/cmd_bootm.c Image header has correct magic number
1165 -2 common/cmd_bootm.c Image header has bad checksum
1166 3 common/cmd_bootm.c Image header has correct checksum
1167 -3 common/cmd_bootm.c Image data has bad checksum
1168 4 common/cmd_bootm.c Image data has correct checksum
1169 -4 common/cmd_bootm.c Image is for unsupported architecture
1170 5 common/cmd_bootm.c Architecture check OK
1171 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1172 6 common/cmd_bootm.c Image Type check OK
1173 -6 common/cmd_bootm.c gunzip uncompression error
1174 -7 common/cmd_bootm.c Unimplemented compression type
1175 7 common/cmd_bootm.c Uncompression OK
1176 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1177 8 common/cmd_bootm.c Image Type check OK
1178 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1179 9 common/cmd_bootm.c Start initial ramdisk verification
1180 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1181 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1182 10 common/cmd_bootm.c Ramdisk header is OK
1183 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1184 11 common/cmd_bootm.c Ramdisk data has correct checksum
1185 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1186 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1187 13 common/cmd_bootm.c Start multifile image verification
1188 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1189 15 common/cmd_bootm.c All preparation done, transferring control to OS
1190
1191 -1 common/cmd_doc.c Bad usage of "doc" command
1192 -1 common/cmd_doc.c No boot device
1193 -1 common/cmd_doc.c Unknown Chip ID on boot device
1194 -1 common/cmd_doc.c Read Error on boot device
1195 -1 common/cmd_doc.c Image header has bad magic number
1196
1197 -1 common/cmd_ide.c Bad usage of "ide" command
1198 -1 common/cmd_ide.c No boot device
1199 -1 common/cmd_ide.c Unknown boot device
1200 -1 common/cmd_ide.c Unknown partition table
1201 -1 common/cmd_ide.c Invalid partition type
1202 -1 common/cmd_ide.c Read Error on boot device
1203 -1 common/cmd_ide.c Image header has bad magic number
1204
1205 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1206
1207
1208Modem Support:
1209--------------
1210
1211[so far only for SMDK2400 board]
1212
1213- Modem support endable:
1214 CONFIG_MODEM_SUPPORT
1215
1216- RTS/CTS Flow control enable:
1217 CONFIG_HWFLOW
1218
1219- Modem debug support:
1220 CONFIG_MODEM_SUPPORT_DEBUG
1221
1222 Enables debugging stuff (char screen[1024], dbg())
1223 for modem support. Useful only with BDI2000.
1224
1225- General:
1226
1227 In the target system modem support is enabled when a
1228 specific key (key combination) is pressed during
1229 power-on. Otherwise U-Boot will boot normally
1230 (autoboot). The key_pressed() fuction is called from
1231 board_init(). Currently key_pressed() is a dummy
1232 function, returning 1 and thus enabling modem
1233 initialization.
1234
1235 If there are no modem init strings in the
1236 environment, U-Boot proceed to autoboot; the
1237 previous output (banner, info printfs) will be
1238 supressed, though.
1239
1240 See also: doc/README.Modem
1241
1242
1243
1244
1245Configuration Settings:
1246-----------------------
1247
1248- CFG_LONGHELP: Defined when you want long help messages included;
1249 undefine this when you're short of memory.
1250
1251- CFG_PROMPT: This is what U-Boot prints on the console to
1252 prompt for user input.
1253
1254- CFG_CBSIZE: Buffer size for input from the Console
1255
1256- CFG_PBSIZE: Buffer size for Console output
1257
1258- CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1259
1260- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1261 the application (usually a Linux kernel) when it is
1262 booted
1263
1264- CFG_BAUDRATE_TABLE:
1265 List of legal baudrate settings for this board.
1266
1267- CFG_CONSOLE_INFO_QUIET
1268 Suppress display of console information at boot.
1269
1270- CFG_CONSOLE_IS_IN_ENV
1271 If the board specific function
1272 extern int overwrite_console (void);
1273 returns 1, the stdin, stderr and stdout are switched to the
1274 serial port, else the settings in the environment are used.
1275
1276- CFG_CONSOLE_OVERWRITE_ROUTINE
1277 Enable the call to overwrite_console().
1278
1279- CFG_CONSOLE_ENV_OVERWRITE
1280 Enable overwrite of previous console environment settings.
1281
1282- CFG_MEMTEST_START, CFG_MEMTEST_END:
1283 Begin and End addresses of the area used by the
1284 simple memory test.
1285
1286- CFG_ALT_MEMTEST:
1287 Enable an alternate, more extensive memory test.
1288
1289- CFG_TFTP_LOADADDR:
1290 Default load address for network file downloads
1291
1292- CFG_LOADS_BAUD_CHANGE:
1293 Enable temporary baudrate change while serial download
1294
1295- CFG_SDRAM_BASE:
1296 Physical start address of SDRAM. _Must_ be 0 here.
1297
1298- CFG_MBIO_BASE:
1299 Physical start address of Motherboard I/O (if using a
1300 Cogent motherboard)
1301
1302- CFG_FLASH_BASE:
1303 Physical start address of Flash memory.
1304
1305- CFG_MONITOR_BASE:
1306 Physical start address of boot monitor code (set by
1307 make config files to be same as the text base address
1308 (TEXT_BASE) used when linking) - same as
1309 CFG_FLASH_BASE when booting from flash.
1310
1311- CFG_MONITOR_LEN:
1312 Size of memory reserved for monitor code
1313
1314- CFG_MALLOC_LEN:
1315 Size of DRAM reserved for malloc() use.
1316
1317- CFG_BOOTMAPSZ:
1318 Maximum size of memory mapped by the startup code of
1319 the Linux kernel; all data that must be processed by
1320 the Linux kernel (bd_info, boot arguments, eventually
1321 initrd image) must be put below this limit.
1322
1323- CFG_MAX_FLASH_BANKS:
1324 Max number of Flash memory banks
1325
1326- CFG_MAX_FLASH_SECT:
1327 Max number of sectors on a Flash chip
1328
1329- CFG_FLASH_ERASE_TOUT:
1330 Timeout for Flash erase operations (in ms)
1331
1332- CFG_FLASH_WRITE_TOUT:
1333 Timeout for Flash write operations (in ms)
1334
1335- CFG_DIRECT_FLASH_TFTP:
1336
1337 Enable TFTP transfers directly to flash memory;
1338 without this option such a download has to be
1339 performed in two steps: (1) download to RAM, and (2)
1340 copy from RAM to flash.
1341
1342 The two-step approach is usually more reliable, since
1343 you can check if the download worked before you erase
1344 the flash, but in some situations (when sytem RAM is
1345 too limited to allow for a tempory copy of the
1346 downloaded image) this option may be very useful.
1347
1348- CFG_FLASH_CFI:
1349 Define if the flash driver uses extra elements in the
1350 common flash structure for storing flash geometry
1351
1352The following definitions that deal with the placement and management
1353of environment data (variable area); in general, we support the
1354following configurations:
1355
1356- CFG_ENV_IS_IN_FLASH:
1357
1358 Define this if the environment is in flash memory.
1359
1360 a) The environment occupies one whole flash sector, which is
1361 "embedded" in the text segment with the U-Boot code. This
1362 happens usually with "bottom boot sector" or "top boot
1363 sector" type flash chips, which have several smaller
1364 sectors at the start or the end. For instance, such a
1365 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1366 such a case you would place the environment in one of the
1367 4 kB sectors - with U-Boot code before and after it. With
1368 "top boot sector" type flash chips, you would put the
1369 environment in one of the last sectors, leaving a gap
1370 between U-Boot and the environment.
1371
1372 - CFG_ENV_OFFSET:
1373
1374 Offset of environment data (variable area) to the
1375 beginning of flash memory; for instance, with bottom boot
1376 type flash chips the second sector can be used: the offset
1377 for this sector is given here.
1378
1379 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1380
1381 - CFG_ENV_ADDR:
1382
1383 This is just another way to specify the start address of
1384 the flash sector containing the environment (instead of
1385 CFG_ENV_OFFSET).
1386
1387 - CFG_ENV_SECT_SIZE:
1388
1389 Size of the sector containing the environment.
1390
1391
1392 b) Sometimes flash chips have few, equal sized, BIG sectors.
1393 In such a case you don't want to spend a whole sector for
1394 the environment.
1395
1396 - CFG_ENV_SIZE:
1397
1398 If you use this in combination with CFG_ENV_IS_IN_FLASH
1399 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1400 of this flash sector for the environment. This saves
1401 memory for the RAM copy of the environment.
1402
1403 It may also save flash memory if you decide to use this
1404 when your environment is "embedded" within U-Boot code,
1405 since then the remainder of the flash sector could be used
1406 for U-Boot code. It should be pointed out that this is
1407 STRONGLY DISCOURAGED from a robustness point of view:
1408 updating the environment in flash makes it always
1409 necessary to erase the WHOLE sector. If something goes
1410 wrong before the contents has been restored from a copy in
1411 RAM, your target system will be dead.
1412
1413 - CFG_ENV_ADDR_REDUND
1414 CFG_ENV_SIZE_REDUND
1415
1416 These settings describe a second storage area used to hold
1417 a redundand copy of the environment data, so that there is
1418 a valid backup copy in case there is a power failur during
1419 a "saveenv" operation.
1420
1421BE CAREFUL! Any changes to the flash layout, and some changes to the
1422source code will make it necessary to adapt <board>/u-boot.lds*
1423accordingly!
1424
1425
1426- CFG_ENV_IS_IN_NVRAM:
1427
1428 Define this if you have some non-volatile memory device
1429 (NVRAM, battery buffered SRAM) which you want to use for the
1430 environment.
1431
1432 - CFG_ENV_ADDR:
1433 - CFG_ENV_SIZE:
1434
1435 These two #defines are used to determin the memory area you
1436 want to use for environment. It is assumed that this memory
1437 can just be read and written to, without any special
1438 provision.
1439
1440BE CAREFUL! The first access to the environment happens quite early
1441in U-Boot initalization (when we try to get the setting of for the
1442console baudrate). You *MUST* have mappend your NVRAM area then, or
1443U-Boot will hang.
1444
1445Please note that even with NVRAM we still use a copy of the
1446environment in RAM: we could work on NVRAM directly, but we want to
1447keep settings there always unmodified except somebody uses "saveenv"
1448to save the current settings.
1449
1450
1451- CFG_ENV_IS_IN_EEPROM:
1452
1453 Use this if you have an EEPROM or similar serial access
1454 device and a driver for it.
1455
1456 - CFG_ENV_OFFSET:
1457 - CFG_ENV_SIZE:
1458
1459 These two #defines specify the offset and size of the
1460 environment area within the total memory of your EEPROM.
1461
1462 - CFG_I2C_EEPROM_ADDR:
1463 If defined, specified the chip address of the EEPROM device.
1464 The default address is zero.
1465
1466 - CFG_EEPROM_PAGE_WRITE_BITS:
1467 If defined, the number of bits used to address bytes in a
1468 single page in the EEPROM device. A 64 byte page, for example
1469 would require six bits.
1470
1471 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1472 If defined, the number of milliseconds to delay between
1473 page writes. The default is zero milliseconds.
1474
1475 - CFG_I2C_EEPROM_ADDR_LEN:
1476 The length in bytes of the EEPROM memory array address. Note
1477 that this is NOT the chip address length!
1478
1479 - CFG_EEPROM_SIZE:
1480 The size in bytes of the EEPROM device.
1481
1482 - CFG_I2C_EEPROM_ADDR:
1483 If defined, specified the chip address of the EEPROM device.
1484 The default address is zero.
1485
1486 - CFG_EEPROM_PAGE_WRITE_BITS:
1487 If defined, the number of bits used to address bytes in a
1488 single page in the EEPROM device. A 64 byte page, for example
1489 would require six bits.
1490
1491 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1492 If defined, the number of milliseconds to delay between
1493 page writes. The default is zero milliseconds.
1494
1495 - CFG_I2C_EEPROM_ADDR_LEN:
1496 The length in bytes of the EEPROM memory array address. Note
1497 that this is NOT the chip address length!
1498
1499 - CFG_EEPROM_SIZE:
1500 The size in bytes of the EEPROM device.
1501
1502- CFG_SPI_INIT_OFFSET
1503
1504 Defines offset to the initial SPI buffer area in DPRAM. The
1505 area is used at an early stage (ROM part) if the environment
1506 is configured to reside in the SPI EEPROM: We need a 520 byte
1507 scratch DPRAM area. It is used between the two initialization
1508 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1509 to be a good choice since it makes it far enough from the
1510 start of the data area as well as from the stack pointer.
1511
1512Please note that the environment is read-only as long as the monitor
1513has been relocated to RAM and a RAM copy of the environment has been
1514created; also, when using EEPROM you will have to use getenv_r()
1515until then to read environment variables.
1516
1517The environment is now protected by a CRC32 checksum. Before the
1518monitor is relocated into RAM, as a result of a bad CRC you will be
1519working with the compiled-in default environment - *silently*!!!
1520[This is necessary, because the first environment variable we need is
1521the "baudrate" setting for the console - if we have a bad CRC, we
1522don't have any device yet where we could complain.]
1523
1524Note: once the monitor has been relocated, then it will complain if
1525the default environment is used; a new CRC is computed as soon as you
1526use the "setenv" command to modify / delete / add any environment
1527variable [even when you try to delete a non-existing variable!].
1528
1529Note2: you must edit your u-boot.lds file to reflect this
1530configuration.
1531
1532
wdenkc6097192002-11-03 00:24:07 +00001533Low Level (hardware related) configuration options:
1534
1535- CFG_CACHELINE_SIZE:
1536 Cache Line Size of the CPU.
1537
1538- CFG_DEFAULT_IMMR:
1539 Default address of the IMMR after system reset.
1540 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1541 to be able to adjust the position of the IMMR
1542 register after a reset.
1543
wdenk7f6c2cb2002-11-10 22:06:23 +00001544- Floppy Disk Support:
1545 CFG_FDC_DRIVE_NUMBER
1546
1547 the default drive number (default value 0)
1548
1549 CFG_ISA_IO_STRIDE
1550
1551 defines the spacing between fdc chipset registers
1552 (default value 1)
1553
1554 CFG_ISA_IO_OFFSET
1555
1556 defines the offset of register from address. It
1557 depends on which part of the data bus is connected to
1558 the fdc chipset. (default value 0)
1559
1560 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1561 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1562 default value.
1563
1564 if CFG_FDC_HW_INIT is defined, then the function
1565 fdc_hw_init() is called at the beginning of the FDC
1566 setup. fdc_hw_init() must be provided by the board
1567 source code. It is used to make hardware dependant
1568 initializations.
1569
wdenkc6097192002-11-03 00:24:07 +00001570- CFG_IMMR: Physical address of the Internal Memory Mapped
1571 Register; DO NOT CHANGE! (11-4)
1572 [MPC8xx systems only]
1573
1574- CFG_INIT_RAM_ADDR:
1575
1576 Start address of memory area tha can be used for
1577 initial data and stack; please note that this must be
1578 writable memory that is working WITHOUT special
1579 initialization, i. e. you CANNOT use normal RAM which
1580 will become available only after programming the
1581 memory controller and running certain initialization
1582 sequences.
1583
1584 U-Boot uses the following memory types:
1585 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1586 - MPC824X: data cache
1587 - PPC4xx: data cache
1588
1589- CFG_INIT_DATA_OFFSET:
1590
1591 Offset of the initial data structure in the memory
1592 area defined by CFG_INIT_RAM_ADDR. Usually
1593 CFG_INIT_DATA_OFFSET is chosen such that the initial
1594 data is located at the end of the available space
1595 (sometimes written as (CFG_INIT_RAM_END -
1596 CFG_INIT_DATA_SIZE), and the initial stack is just
1597 below that area (growing from (CFG_INIT_RAM_ADDR +
1598 CFG_INIT_DATA_OFFSET) downward.
1599
1600 Note:
1601 On the MPC824X (or other systems that use the data
1602 cache for initial memory) the address chosen for
1603 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1604 point to an otherwise UNUSED address space between
1605 the top of RAM and the start of the PCI space.
1606
1607- CFG_SIUMCR: SIU Module Configuration (11-6)
1608
1609- CFG_SYPCR: System Protection Control (11-9)
1610
1611- CFG_TBSCR: Time Base Status and Control (11-26)
1612
1613- CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1614
1615- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1616
1617- CFG_SCCR: System Clock and reset Control Register (15-27)
1618
1619- CFG_OR_TIMING_SDRAM:
1620 SDRAM timing
1621
1622- CFG_MAMR_PTA:
1623 periodic timer for refresh
1624
1625- CFG_DER: Debug Event Register (37-47)
1626
1627- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1628 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1629 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1630 CFG_BR1_PRELIM:
1631 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1632
1633- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1634 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1635 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1636 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1637
1638- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1639 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1640 Machine Mode Register and Memory Periodic Timer
1641 Prescaler definitions (SDRAM timing)
1642
1643- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1644 enable I2C microcode relocation patch (MPC8xx);
1645 define relocation offset in DPRAM [DSP2]
1646
1647- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1648 enable SPI microcode relocation patch (MPC8xx);
1649 define relocation offset in DPRAM [SCC4]
1650
1651- CFG_USE_OSCCLK:
1652 Use OSCM clock mode on MBX8xx board. Be careful,
1653 wrong setting might damage your board. Read
1654 doc/README.MBX before setting this variable!
1655
1656Building the Software:
1657======================
1658
1659Building U-Boot has been tested in native PPC environments (on a
1660PowerBook G3 running LinuxPPC 2000) and in cross environments
1661(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1662NetBSD 1.5 on x86).
1663
1664If you are not using a native PPC environment, it is assumed that you
1665have the GNU cross compiling tools available in your path and named
1666with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1667you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1668the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1669change it to:
1670
1671 CROSS_COMPILE = ppc_4xx-
1672
1673
1674U-Boot is intended to be simple to build. After installing the
1675sources you must configure U-Boot for one specific board type. This
1676is done by typing:
1677
1678 make NAME_config
1679
1680where "NAME_config" is the name of one of the existing
1681configurations; the following names are supported:
1682
1683 ADCIOP_config GTH_config TQM850L_config
1684 ADS860_config IP860_config TQM855L_config
1685 AR405_config IVML24_config TQM860L_config
1686 CANBT_config IVMS8_config WALNUT405_config
1687 CPCI405_config LANTEC_config cogent_common_config
1688 CPCIISER4_config MBX_config cogent_mpc8260_config
1689 CU824_config MBX860T_config cogent_mpc8xx_config
1690 ESTEEM192E_config RPXlite_config hermes_config
1691 ETX094_config RPXsuper_config hymod_config
1692 FADS823_config SM850_config lwmon_config
1693 FADS850SAR_config SPD823TS_config pcu_e_config
1694 FADS860T_config SXNI855T_config rsdproto_config
1695 FPS850L_config Sandpoint8240_config sbc8260_config
1696 GENIETV_config TQM823L_config PIP405_config
wdenk384ae022002-11-05 00:17:55 +00001697 GEN860T_config EBONY_config FPS860L_config
wdenkc6097192002-11-03 00:24:07 +00001698
1699Note: for some board special configuration names may exist; check if
1700 additional information is available from the board vendor; for
1701 instance, the TQM8xxL systems run normally at 50 MHz and use a
1702 SCC for 10baseT ethernet; there are also systems with 80 MHz
1703 CPU clock, and an optional Fast Ethernet module is available
1704 for CPU's with FEC. You can select such additional "features"
1705 when chosing the configuration, i. e.
1706
1707 make TQM860L_config
1708 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1709
1710 make TQM860L_FEC_config
1711 - will configure for a TQM860L at 50MHz with FEC for ethernet
1712
1713 make TQM860L_80MHz_config
1714 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1715 interface
1716
1717 make TQM860L_FEC_80MHz_config
1718 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1719
1720 make TQM823L_LCD_config
1721 - will configure for a TQM823L with U-Boot console on LCD
1722
1723 make TQM823L_LCD_80MHz_config
1724 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1725
1726 etc.
1727
1728
1729
wdenk24ee89b2002-11-03 17:56:27 +00001730Finally, type "make all", and you should get some working U-Boot
wdenkc6097192002-11-03 00:24:07 +00001731images ready for downlod to / installation on your system:
1732
1733- "u-boot.bin" is a raw binary image
1734- "u-boot" is an image in ELF binary format
1735- "u-boot.srec" is in Motorola S-Record format
1736
1737
1738Please be aware that the Makefiles assume you are using GNU make, so
1739for instance on NetBSD you might need to use "gmake" instead of
1740native "make".
1741
1742
1743If the system board that you have is not listed, then you will need
1744to port U-Boot to your hardware platform. To do this, follow these
1745steps:
1746
17471. Add a new configuration option for your board to the toplevel
1748 "Makefile", using the existing entries as examples.
17492. Create a new directory to hold your board specific code. Add any
1750 files you need.
17513. If you're porting U-Boot to a new CPU, then also create a new
1752 directory to hold your CPU specific code. Add any files you need.
17534. Run "make config_name" with your new name.
17545. Type "make", and you should get a working "u-boot.srec" file
1755 to be installed on your target system.
1756 [Of course, this last step is much harder than it sounds.]
1757
1758
1759Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1760==============================================================
1761
1762If you have modified U-Boot sources (for instance added a new board
1763or support for new devices, a new CPU, etc.) you are expected to
1764provide feedback to the other developers. The feedback normally takes
1765the form of a "patch", i. e. a context diff against a certain (latest
1766official or latest in CVS) version of U-Boot sources.
1767
1768But before you submit such a patch, please verify that your modifi-
1769cation did not break existing code. At least make sure that *ALL* of
1770the supported boards compile WITHOUT ANY compiler warnings. To do so,
1771just run the "MAKEALL" script, which will configure and build U-Boot
1772for ALL supported system. Be warned, this will take a while. You can
1773select which (cross) compiler to use py passing a `CROSS_COMPILE'
1774environment variable to the script, i. e. to use the cross tools from
1775MontaVista's Hard Hat Linux you can type
1776
1777 CROSS_COMPILE=ppc_8xx- MAKEALL
1778
1779or to build on a native PowerPC system you can type
1780
1781 CROSS_COMPILE=' ' MAKEALL
1782
1783See also "U-Boot Porting Guide" below.
1784
1785
1786
1787Monitor Commands - Overview:
1788============================
1789
1790go - start application at address 'addr'
1791run - run commands in an environment variable
1792bootm - boot application image from memory
1793bootp - boot image via network using BootP/TFTP protocol
1794tftpboot- boot image via network using TFTP protocol
1795 and env variables "ipaddr" and "serverip"
1796 (and eventually "gatewayip")
1797rarpboot- boot image via network using RARP/TFTP protocol
1798diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1799loads - load S-Record file over serial line
1800loadb - load binary file over serial line (kermit mode)
1801md - memory display
1802mm - memory modify (auto-incrementing)
1803nm - memory modify (constant address)
1804mw - memory write (fill)
1805cp - memory copy
1806cmp - memory compare
1807crc32 - checksum calculation
1808imd - i2c memory display
1809imm - i2c memory modify (auto-incrementing)
1810inm - i2c memory modify (constant address)
1811imw - i2c memory write (fill)
1812icrc32 - i2c checksum calculation
1813iprobe - probe to discover valid I2C chip addresses
1814iloop - infinite loop on address range
1815isdram - print SDRAM configuration information
1816sspi - SPI utility commands
1817base - print or set address offset
1818printenv- print environment variables
1819setenv - set environment variables
1820saveenv - save environment variables to persistent storage
1821protect - enable or disable FLASH write protection
1822erase - erase FLASH memory
1823flinfo - print FLASH memory information
1824bdinfo - print Board Info structure
1825iminfo - print header information for application image
1826coninfo - print console devices and informations
1827ide - IDE sub-system
1828loop - infinite loop on address range
1829mtest - simple RAM test
1830icache - enable or disable instruction cache
1831dcache - enable or disable data cache
1832reset - Perform RESET of the CPU
1833echo - echo args to console
1834version - print monitor version
1835help - print online help
1836? - alias for 'help'
1837
1838
1839Monitor Commands - Detailed Description:
1840========================================
1841
1842TODO.
1843
1844For now: just type "help <command>".
1845
1846
1847Environment Variables:
1848======================
1849
1850U-Boot supports user configuration using Environment Variables which
1851can be made persistent by saving to Flash memory.
1852
1853Environment Variables are set using "setenv", printed using
1854"printenv", and saved to Flash using "saveenv". Using "setenv"
1855without a value can be used to delete a variable from the
1856environment. As long as you don't save the environment you are
1857working with an in-memory copy. In case the Flash area containing the
1858environment is erased by accident, a default environment is provided.
1859
1860Some configuration options can be set using Environment Variables:
1861
1862 baudrate - see CONFIG_BAUDRATE
1863
1864 bootdelay - see CONFIG_BOOTDELAY
1865
1866 bootcmd - see CONFIG_BOOTCOMMAND
1867
1868 bootargs - Boot arguments when booting an RTOS image
1869
1870 bootfile - Name of the image to load with TFTP
1871
1872 autoload - if set to "no" (any string beginning with 'n'),
1873 "bootp" will just load perform a lookup of the
1874 configuration from the BOOTP server, but not try to
1875 load any image using TFTP
1876
1877 autostart - if set to "yes", an image loaded using the "bootp",
1878 "rarpboot", "tftpboot" or "diskboot" commands will
1879 be automatically started (by internally calling
1880 "bootm")
1881
1882 initrd_high - restrict positioning of initrd images:
1883 If this variable is not set, initrd images will be
1884 copied to the highest possible address in RAM; this
1885 is usually what you want since it allows for
1886 maximum initrd size. If for some reason you want to
1887 make sure that the initrd image is loaded below the
1888 CFG_BOOTMAPSZ limit, you can set this environment
1889 variable to a value of "no" or "off" or "0".
1890 Alternatively, you can set it to a maximum upper
1891 address to use (U-Boot will still check that it
1892 does not overwrite the U-Boot stack and data).
1893
1894 For instance, when you have a system with 16 MB
1895 RAM, and want to reseve 4 MB from use by Linux,
1896 you can do this by adding "mem=12M" to the value of
1897 the "bootargs" variable. However, now you must make
1898 sure, that the initrd image is placed in the first
1899 12 MB as well - this can be done with
1900
1901 setenv initrd_high 00c00000
1902
1903 ipaddr - IP address; needed for tftpboot command
1904
1905 loadaddr - Default load address for commands like "bootp",
1906 "rarpboot", "tftpboot" or "diskboot"
1907
1908 loads_echo - see CONFIG_LOADS_ECHO
1909
1910 serverip - TFTP server IP address; needed for tftpboot command
1911
1912 bootretry - see CONFIG_BOOT_RETRY_TIME
1913
1914 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
1915
1916 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
1917
1918
1919The following environment variables may be used and automatically
1920updated by the network boot commands ("bootp" and "rarpboot"),
1921depending the information provided by your boot server:
1922
1923 bootfile - see above
1924 dnsip - IP address of your Domain Name Server
1925 gatewayip - IP address of the Gateway (Router) to use
1926 hostname - Target hostname
1927 ipaddr - see above
1928 netmask - Subnet Mask
1929 rootpath - Pathname of the root filesystem on the NFS server
1930 serverip - see above
1931
1932
1933There are two special Environment Variables:
1934
1935 serial# - contains hardware identification information such
1936 as type string and/or serial number
1937 ethaddr - Ethernet address
1938
1939These variables can be set only once (usually during manufacturing of
1940the board). U-Boot refuses to delete or overwrite these variables
1941once they have been set once.
1942
1943
1944Please note that changes to some configuration parameters may take
1945only effect after the next boot (yes, that's just like Windoze :-).
1946
1947
1948Note for Redundant Ethernet Interfaces:
1949=======================================
1950
1951Some boards come with redundand ethernet interfaces; U-Boot supports
1952such configurations and is capable of automatic selection of a
1953"working" interface when needed. MAC assignemnt works as follows:
1954
1955Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
1956MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
1957"eth1addr" (=>eth1), "eth2addr", ...
1958
1959If the network interface stores some valid MAC address (for instance
1960in SROM), this is used as default address if there is NO correspon-
1961ding setting in the environment; if the corresponding environment
1962variable is set, this overrides the settings in the card; that means:
1963
1964o If the SROM has a valid MAC address, and there is no address in the
1965 environment, the SROM's address is used.
1966
1967o If there is no valid address in the SROM, and a definition in the
1968 environment exists, then the value from the environment variable is
1969 used.
1970
1971o If both the SROM and the environment contain a MAC address, and
1972 both addresses are the same, this MAC address is used.
1973
1974o If both the SROM and the environment contain a MAC address, and the
1975 addresses differ, the value from the environment is used and a
1976 warning is printed.
1977
1978o If neither SROM nor the environment contain a MAC address, an error
1979 is raised.
1980
1981
1982
1983Image Formats:
1984==============
1985
1986The "boot" commands of this monitor operate on "image" files which
1987can be basicly anything, preceeded by a special header; see the
1988definitions in include/image.h for details; basicly, the header
1989defines the following image properties:
1990
1991* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
1992 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
1993 LynxOS, pSOS, QNX;
1994 Currently supported: Linux, NetBSD, VxWorks, QNX).
1995* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
1996 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
1997 Currently supported: PowerPC).
1998* Compression Type (Provisions for uncompressed, gzip, bzip2;
1999 Currently supported: uncompressed, gzip).
2000* Load Address
2001* Entry Point
2002* Image Name
2003* Image Timestamp
2004
2005The header is marked by a special Magic Number, and both the header
2006and the data portions of the image are secured against corruption by
2007CRC32 checksums.
2008
2009
2010Linux Support:
2011==============
2012
2013Although U-Boot should support any OS or standalone application
2014easily, Linux has always been in the focus during the design of
2015U-Boot.
2016
2017U-Boot includes many features that so far have been part of some
2018special "boot loader" code within the Linux kernel. Also, any
2019"initrd" images to be used are no longer part of one big Linux image;
2020instead, kernel and "initrd" are separate images. This implementation
2021serves serveral purposes:
2022
2023- the same features can be used for other OS or standalone
2024 applications (for instance: using compressed images to reduce the
2025 Flash memory footprint)
2026
2027- it becomes much easier to port new Linux kernel versions because
2028 lots of low-level, hardware dependend stuff are done by U-Boot
2029
2030- the same Linux kernel image can now be used with different "initrd"
2031 images; of course this also means that different kernel images can
2032 be run with the same "initrd". This makes testing easier (you don't
2033 have to build a new "zImage.initrd" Linux image when you just
2034 change a file in your "initrd"). Also, a field-upgrade of the
2035 software is easier now.
2036
2037
2038Linux HOWTO:
2039============
2040
2041Porting Linux to U-Boot based systems:
2042---------------------------------------
2043
2044U-Boot cannot save you from doing all the necessary modifications to
2045configure the Linux device drivers for use with your target hardware
2046(no, we don't intend to provide a full virtual machine interface to
2047Linux :-).
2048
2049But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2050
2051Just make sure your machine specific header file (for instance
2052include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2053Information structure as we define in include/u-boot.h, and make
2054sure that your definition of IMAP_ADDR uses the same value as your
2055U-Boot configuration in CFG_IMMR.
2056
2057
2058Configuring the Linux kernel:
2059-----------------------------
2060
2061No specific requirements for U-Boot. Make sure you have some root
2062device (initial ramdisk, NFS) for your target system.
2063
2064
2065Building a Linux Image:
2066-----------------------
2067
wdenk24ee89b2002-11-03 17:56:27 +00002068With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2069not used. If you use recent kernel source, a new build target
2070"uImage" will exist which automatically builds an image usable by
2071U-Boot. Most older kernels also have support for a "pImage" target,
2072which was introduced for our predecessor project PPCBoot and uses a
2073100% compatible format.
wdenkc6097192002-11-03 00:24:07 +00002074
2075Example:
2076
2077 make TQM850L_config
2078 make oldconfig
2079 make dep
wdenk24ee89b2002-11-03 17:56:27 +00002080 make uImage
wdenkc6097192002-11-03 00:24:07 +00002081
wdenk24ee89b2002-11-03 17:56:27 +00002082The "uImage" build target uses a special tool (in 'tools/mkimage') to
2083encapsulate a compressed Linux kernel image with header information,
2084CRC32 checksum etc. for use with U-Boot. This is what we are doing:
wdenkc6097192002-11-03 00:24:07 +00002085
wdenk24ee89b2002-11-03 17:56:27 +00002086* build a standard "vmlinux" kernel image (in ELF binary format):
wdenkc6097192002-11-03 00:24:07 +00002087
wdenk24ee89b2002-11-03 17:56:27 +00002088* convert the kernel into a raw binary image:
2089
2090 ${CROSS_COMPILE}-objcopy -O binary \
2091 -R .note -R .comment \
2092 -S vmlinux linux.bin
2093
2094* compress the binary image:
2095
2096 gzip -9 linux.bin
2097
2098* package compressed binary image for U-Boot:
2099
2100 mkimage -A ppc -O linux -T kernel -C gzip \
2101 -a 0 -e 0 -n "Linux Kernel Image" \
2102 -d linux.bin.gz uImage
2103
2104
2105The "mkimage" tool can also be used to create ramdisk images for use
2106with U-Boot, either separated from the Linux kernel image, or
2107combined into one file. "mkimage" encapsulates the images with a 64
2108byte header containing information about target architecture,
2109operating system, image type, compression method, entry points, time
2110stamp, CRC32 checksums, etc.
2111
2112"mkimage" can be called in two ways: to verify existing images and
2113print the header information, or to build new images.
2114
2115In the first form (with "-l" option) mkimage lists the information
2116contained in the header of an existing U-Boot image; this includes
wdenkc6097192002-11-03 00:24:07 +00002117checksum verification:
2118
2119 tools/mkimage -l image
2120 -l ==> list image header information
2121
2122The second form (with "-d" option) is used to build a U-Boot image
2123from a "data file" which is used as image payload:
2124
2125 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2126 -n name -d data_file image
2127 -A ==> set architecture to 'arch'
2128 -O ==> set operating system to 'os'
2129 -T ==> set image type to 'type'
2130 -C ==> set compression type 'comp'
2131 -a ==> set load address to 'addr' (hex)
2132 -e ==> set entry point to 'ep' (hex)
2133 -n ==> set image name to 'name'
2134 -d ==> use image data from 'datafile'
2135
2136Right now, all Linux kernels use the same load address (0x00000000),
2137but the entry point address depends on the kernel version:
2138
2139- 2.2.x kernels have the entry point at 0x0000000C,
wdenk24ee89b2002-11-03 17:56:27 +00002140- 2.3.x and later kernels have the entry point at 0x00000000.
wdenkc6097192002-11-03 00:24:07 +00002141
2142So a typical call to build a U-Boot image would read:
2143
wdenk24ee89b2002-11-03 17:56:27 +00002144 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2145 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2146 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2147 > examples/uImage.TQM850L
2148 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002149 Created: Wed Jul 19 02:34:59 2000
2150 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2151 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2152 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002153 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002154
2155To verify the contents of the image (or check for corruption):
2156
wdenk24ee89b2002-11-03 17:56:27 +00002157 -> tools/mkimage -l examples/uImage.TQM850L
2158 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002159 Created: Wed Jul 19 02:34:59 2000
2160 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2161 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2162 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002163 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002164
2165NOTE: for embedded systems where boot time is critical you can trade
2166speed for memory and install an UNCOMPRESSED image instead: this
2167needs more space in Flash, but boots much faster since it does not
2168need to be uncompressed:
2169
wdenk24ee89b2002-11-03 17:56:27 +00002170 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2171 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2172 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2173 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2174 > examples/uImage.TQM850L-uncompressed
2175 Image Name: 2.4.4 kernel for TQM850L
wdenkc6097192002-11-03 00:24:07 +00002176 Created: Wed Jul 19 02:34:59 2000
2177 Image Type: PowerPC Linux Kernel Image (uncompressed)
2178 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2179 Load Address: 0x00000000
wdenk24ee89b2002-11-03 17:56:27 +00002180 Entry Point: 0x00000000
wdenkc6097192002-11-03 00:24:07 +00002181
2182
2183Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2184when your kernel is intended to use an initial ramdisk:
2185
2186 -> tools/mkimage -n 'Simple Ramdisk Image' \
2187 > -A ppc -O linux -T ramdisk -C gzip \
2188 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2189 Image Name: Simple Ramdisk Image
2190 Created: Wed Jan 12 14:01:50 2000
2191 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2192 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2193 Load Address: 0x00000000
2194 Entry Point: 0x00000000
2195
2196
2197Installing a Linux Image:
2198-------------------------
2199
2200To downloading a U-Boot image over the serial (console) interface,
2201you must convert the image to S-Record format:
2202
2203 objcopy -I binary -O srec examples/image examples/image.srec
2204
2205The 'objcopy' does not understand the information in the U-Boot
2206image header, so the resulting S-Record file will be relative to
2207address 0x00000000. To load it to a given address, you need to
2208specify the target address as 'offset' parameter with the 'loads'
2209command.
2210
2211Example: install the image to address 0x40100000 (which on the
2212TQM8xxL is in the first Flash bank):
2213
2214 => erase 40100000 401FFFFF
2215
2216 .......... done
2217 Erased 8 sectors
2218
2219 => loads 40100000
2220 ## Ready for S-Record download ...
2221 ~>examples/image.srec
2222 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2223 ...
2224 15989 15990 15991 15992
2225 [file transfer complete]
2226 [connected]
2227 ## Start Addr = 0x00000000
2228
2229
2230You can check the success of the download using the 'iminfo' command;
2231this includes a checksum verification so you can be sure no data
2232corruption happened:
2233
2234 => imi 40100000
2235
2236 ## Checking Image at 40100000 ...
2237 Image Name: 2.2.13 for initrd on TQM850L
2238 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2239 Data Size: 335725 Bytes = 327 kB = 0 MB
2240 Load Address: 00000000
2241 Entry Point: 0000000c
2242 Verifying Checksum ... OK
2243
2244
2245
2246Boot Linux:
2247-----------
2248
2249The "bootm" command is used to boot an application that is stored in
2250memory (RAM or Flash). In case of a Linux kernel image, the contents
2251of the "bootargs" environment variable is passed to the kernel as
2252parameters. You can check and modify this variable using the
2253"printenv" and "setenv" commands:
2254
2255
2256 => printenv bootargs
2257 bootargs=root=/dev/ram
2258
2259 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2260
2261 => printenv bootargs
2262 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2263
2264 => bootm 40020000
2265 ## Booting Linux kernel at 40020000 ...
2266 Image Name: 2.2.13 for NFS on TQM850L
2267 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2268 Data Size: 381681 Bytes = 372 kB = 0 MB
2269 Load Address: 00000000
2270 Entry Point: 0000000c
2271 Verifying Checksum ... OK
2272 Uncompressing Kernel Image ... OK
2273 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
2274 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2275 time_init: decrementer frequency = 187500000/60
2276 Calibrating delay loop... 49.77 BogoMIPS
2277 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2278 ...
2279
2280If you want to boot a Linux kernel with initial ram disk, you pass
2281the memory addreses of both the kernel and the initrd image (PPBCOOT
2282format!) to the "bootm" command:
2283
2284 => imi 40100000 40200000
2285
2286 ## Checking Image at 40100000 ...
2287 Image Name: 2.2.13 for initrd on TQM850L
2288 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2289 Data Size: 335725 Bytes = 327 kB = 0 MB
2290 Load Address: 00000000
2291 Entry Point: 0000000c
2292 Verifying Checksum ... OK
2293
2294 ## Checking Image at 40200000 ...
2295 Image Name: Simple Ramdisk Image
2296 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2297 Data Size: 566530 Bytes = 553 kB = 0 MB
2298 Load Address: 00000000
2299 Entry Point: 00000000
2300 Verifying Checksum ... OK
2301
2302 => bootm 40100000 40200000
2303 ## Booting Linux kernel at 40100000 ...
2304 Image Name: 2.2.13 for initrd on TQM850L
2305 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2306 Data Size: 335725 Bytes = 327 kB = 0 MB
2307 Load Address: 00000000
2308 Entry Point: 0000000c
2309 Verifying Checksum ... OK
2310 Uncompressing Kernel Image ... OK
2311 ## Loading RAMDisk Image at 40200000 ...
2312 Image Name: Simple Ramdisk Image
2313 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2314 Data Size: 566530 Bytes = 553 kB = 0 MB
2315 Load Address: 00000000
2316 Entry Point: 00000000
2317 Verifying Checksum ... OK
2318 Loading Ramdisk ... OK
2319 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
2320 Boot arguments: root=/dev/ram
2321 time_init: decrementer frequency = 187500000/60
2322 Calibrating delay loop... 49.77 BogoMIPS
2323 ...
2324 RAMDISK: Compressed image found at block 0
2325 VFS: Mounted root (ext2 filesystem).
2326
2327 bash#
2328
2329
2330Standalone HOWTO:
2331=================
2332
2333One of the features of U-Boot is that you can dynamically load and
2334run "standalone" applications, which can use some resources of
2335U-Boot like console I/O functions or interrupt services.
2336
2337Two simple examples are included with the sources:
2338
2339"Hello World" Demo:
2340-------------------
2341
2342'examples/hello_world.c' contains a small "Hello World" Demo
2343application; it is automatically compiled when you build U-Boot.
2344It's configured to run at address 0x00040004, so you can play with it
2345like that:
2346
2347 => loads
2348 ## Ready for S-Record download ...
2349 ~>examples/hello_world.srec
2350 1 2 3 4 5 6 7 8 9 10 11 ...
2351 [file transfer complete]
2352 [connected]
2353 ## Start Addr = 0x00040004
2354
2355 => go 40004 Hello World! This is a test.
2356 ## Starting application at 0x00040004 ...
2357 Hello World
2358 argc = 7
2359 argv[0] = "40004"
2360 argv[1] = "Hello"
2361 argv[2] = "World!"
2362 argv[3] = "This"
2363 argv[4] = "is"
2364 argv[5] = "a"
2365 argv[6] = "test."
2366 argv[7] = "<NULL>"
2367 Hit any key to exit ...
2368
2369 ## Application terminated, rc = 0x0
2370
2371Another example, which demonstrates how to register a CPM interrupt
2372handler with the U-Boot code, can be found in 'examples/timer.c'.
2373Here, a CPM timer is set up to generate an interrupt every second.
2374The interrupt service routine is trivial, just printing a '.'
2375character, but this is just a demo program. The application can be
2376controlled by the following keys:
2377
2378 ? - print current values og the CPM Timer registers
2379 b - enable interrupts and start timer
2380 e - stop timer and disable interrupts
2381 q - quit application
2382
2383 => loads
2384 ## Ready for S-Record download ...
2385 ~>examples/timer.srec
2386 1 2 3 4 5 6 7 8 9 10 11 ...
2387 [file transfer complete]
2388 [connected]
2389 ## Start Addr = 0x00040004
2390
2391 => go 40004
2392 ## Starting application at 0x00040004 ...
2393 TIMERS=0xfff00980
2394 Using timer 1
2395 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2396
2397Hit 'b':
2398 [q, b, e, ?] Set interval 1000000 us
2399 Enabling timer
2400Hit '?':
2401 [q, b, e, ?] ........
2402 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2403Hit '?':
2404 [q, b, e, ?] .
2405 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2406Hit '?':
2407 [q, b, e, ?] .
2408 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2409Hit '?':
2410 [q, b, e, ?] .
2411 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2412Hit 'e':
2413 [q, b, e, ?] ...Stopping timer
2414Hit 'q':
2415 [q, b, e, ?] ## Application terminated, rc = 0x0
2416
2417
2418NetBSD Notes:
2419=============
2420
2421Starting at version 0.9.2, U-Boot supports NetBSD both as host
2422(build U-Boot) and target system (boots NetBSD/mpc8xx).
2423
2424Building requires a cross environment; it is known to work on
2425NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2426need gmake since the Makefiles are not compatible with BSD make).
2427Note that the cross-powerpc package does not install include files;
2428attempting to build U-Boot will fail because <machine/ansi.h> is
2429missing. This file has to be installed and patched manually:
2430
2431 # cd /usr/pkg/cross/powerpc-netbsd/include
2432 # mkdir powerpc
2433 # ln -s powerpc machine
2434 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2435 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2436
2437Native builds *don't* work due to incompatibilities between native
2438and U-Boot include files.
2439
2440Booting assumes that (the first part of) the image booted is a
2441stage-2 loader which in turn loads and then invokes the kernel
2442proper. Loader sources will eventually appear in the NetBSD source
2443tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2444meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2445details.
2446
2447
2448Implementation Internals:
2449=========================
2450
2451The following is not intended to be a complete description of every
2452implementation detail. However, it should help to understand the
2453inner workings of U-Boot and make it easier to port it to custom
2454hardware.
2455
2456
2457Initial Stack, Global Data:
2458---------------------------
2459
2460The implementation of U-Boot is complicated by the fact that U-Boot
2461starts running out of ROM (flash memory), usually without access to
2462system RAM (because the memory controller is not initialized yet).
2463This means that we don't have writable Data or BSS segments, and BSS
2464is not initialized as zero. To be able to get a C environment working
2465at all, we have to allocate at least a minimal stack. Implementation
2466options for this are defined and restricted by the CPU used: Some CPU
2467models provide on-chip memory (like the IMMR area on MPC8xx and
2468MPC826x processors), on others (parts of) the data cache can be
2469locked as (mis-) used as memory, etc.
2470
2471It is essential to remember this, since it has some impact on the C
2472code for the initialization procedures:
2473
2474* Initialized global data (data segment) is read-only. Do not attempt
2475 to write it.
2476
2477* Do not use any unitialized global data (or implicitely initialized
2478 as zero data - BSS segment) at all - this is undefined, initiali-
2479 zation is performed later (when relocationg to RAM).
2480
2481* Stack space is very limited. Avoid big data buffers or things like
2482 that.
2483
2484Having only the stack as writable memory limits means we cannot use
2485normal global data to share information beween the code. But it
2486turned out that the implementation of U-Boot can be greatly
2487simplified by making a global data structure (gd_t) available to all
2488functions. We could pass a pointer to this data as argument to _all_
2489functions, but this would bloat the code. Instead we use a feature of
2490the GCC compiler (Global Register Variables) to share the data: we
2491place a pointer (gd) to the global data into a register which we
2492reserve for this purpose.
2493
2494When chosing a register for such a purpose we are restricted by the
2495relevant (E)ABI specifications for the current architecture, and by
2496GCC's implementation.
2497
2498For PowerPC, the following registers have specific use:
2499 R1: stack pointer
2500 R2: TOC pointer
2501 R3-R4: parameter passing and return values
2502 R5-R10: parameter passing
2503 R13: small data area pointer
2504 R30: GOT pointer
2505 R31: frame pointer
2506
2507 (U-Boot also uses R14 as internal GOT pointer.)
2508
2509 ==> U-Boot will use R29 to hold a pointer to the global data
2510
2511 Note: on PPC, we could use a static initializer (since the
2512 address of the global data structure is known at compile time),
2513 but it turned out that reserving a register results in somewhat
2514 smaller code - although the code savings are not that big (on
2515 average for all boards 752 bytes for the whole U-Boot image,
2516 624 text + 127 data).
2517
2518On ARM, the following registers are used:
2519
2520 R0: function argument word/integer result
2521 R1-R3: function argument word
2522 R9: GOT pointer
2523 R10: stack limit (used only if stack checking if enabled)
2524 R11: argument (frame) pointer
2525 R12: temporary workspace
2526 R13: stack pointer
2527 R14: link register
2528 R15: program counter
2529
2530 ==> U-Boot will use R8 to hold a pointer to the global data
2531
2532
2533
2534Memory Management:
2535------------------
2536
2537U-Boot runs in system state and uses physical addresses, i.e. the
2538MMU is not used either for address mapping nor for memory protection.
2539
2540The available memory is mapped to fixed addresses using the memory
2541controller. In this process, a contiguous block is formed for each
2542memory type (Flash, SDRAM, SRAM), even when it consists of several
2543physical memory banks.
2544
2545U-Boot is installed in the first 128 kB of the first Flash bank (on
2546TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2547booting and sizing and initializing DRAM, the code relocates itself
2548to the upper end of DRAM. Immediately below the U-Boot code some
2549memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2550configuration setting]. Below that, a structure with global Board
2551Info data is placed, followed by the stack (growing downward).
2552
2553Additionally, some exception handler code is copied to the low 8 kB
2554of DRAM (0x00000000 ... 0x00001FFF).
2555
2556So a typical memory configuration with 16 MB of DRAM could look like
2557this:
2558
2559 0x0000 0000 Exception Vector code
2560 :
2561 0x0000 1FFF
2562 0x0000 2000 Free for Application Use
2563 :
2564 :
2565
2566 :
2567 :
2568 0x00FB FF20 Monitor Stack (Growing downward)
2569 0x00FB FFAC Board Info Data and permanent copy of global data
2570 0x00FC 0000 Malloc Arena
2571 :
2572 0x00FD FFFF
2573 0x00FE 0000 RAM Copy of Monitor Code
2574 ... eventually: LCD or video framebuffer
2575 ... eventually: pRAM (Protected RAM - unchanged by reset)
2576 0x00FF FFFF [End of RAM]
2577
2578
2579System Initialization:
2580----------------------
2581
2582In the reset configuration, U-Boot starts at the reset entry point
2583(on most PowerPC systens at address 0x00000100). Because of the reset
2584configuration for CS0# this is a mirror of the onboard Flash memory.
2585To be able to re-map memory U-Boot then jumps to it's link address.
2586To be able to implement the initialization code in C, a (small!)
2587initial stack is set up in the internal Dual Ported RAM (in case CPUs
2588which provide such a feature like MPC8xx or MPC8260), or in a locked
2589part of the data cache. After that, U-Boot initializes the CPU core,
2590the caches and the SIU.
2591
2592Next, all (potentially) available memory banks are mapped using a
2593preliminary mapping. For example, we put them on 512 MB boundaries
2594(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2595on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2596programmed for SDRAM access. Using the temporary configuration, a
2597simple memory test is run that determines the size of the SDRAM
2598banks.
2599
2600When there is more than one SDRAM bank, and the banks are of
2601different size, the larger is mapped first. For equal size, the first
2602bank (CS2#) is mapped first. The first mapping is always for address
26030x00000000, with any additional banks following immediately to create
2604contiguous memory starting from 0.
2605
2606Then, the monitor installs itself at the upper end of the SDRAM area
2607and allocates memory for use by malloc() and for the global Board
2608Info data; also, the exception vector code is copied to the low RAM
2609pages, and the final stack is set up.
2610
2611Only after this relocation will you have a "normal" C environment;
2612until that you are restricted in several ways, mostly because you are
2613running from ROM, and because the code will have to be relocated to a
2614new address in RAM.
2615
2616
2617U-Boot Porting Guide:
2618----------------------
2619
2620[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2621list, Octover 2002]
2622
2623
2624int main (int argc, char *argv[])
2625{
2626 sighandler_t no_more_time;
2627
2628 signal (SIGALRM, no_more_time);
2629 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2630
2631 if (available_money > available_manpower) {
2632 pay consultant to port U-Boot;
2633 return 0;
2634 }
2635
2636 Download latest U-Boot source;
2637
2638 if (clueless) {
2639 email ("Hi, I am new to U-Boot, how do I get started?");
2640 }
2641
2642 while (learning) {
2643 Read the README file in the top level directory;
2644 Read http://www.denx.de/re/DPLG.html
2645 Read the source, Luke;
2646 }
2647
2648 if (available_money > toLocalCurrency ($2500)) {
2649 Buy a BDI2000;
2650 } else {
2651 Add a lot of aggravation and time;
2652 }
2653
2654 Create your own board support subdirectory;
2655
2656 while (!running) {
2657 do {
2658 Add / modify source code;
2659 } until (compiles);
2660 Debug;
2661 if (clueless)
2662 email ("Hi, I am having problems...");
2663 }
2664 Send patch file to Wolfgang;
2665
2666 return 0;
2667}
2668
2669void no_more_time (int sig)
2670{
2671 hire_a_guru();
2672}
2673
2674
2675
2676Coding Standards:
2677-----------------
2678
2679All contributions to U-Boot should conform to the Linux kernel
2680coding style; see the file "Documentation/CodingStyle" in your Linux
2681kernel source directory.
2682
2683Please note that U-Boot is implemented in C (and to some small parts
2684in Assembler); no C++ is used, so please do not use C++ style
2685comments (//) in your code.
2686
2687Submissions which do not conform to the standards may be returned
2688with a request to reformat the changes.
2689
2690
2691Submitting Patches:
2692-------------------
2693
2694Since the number of patches for U-Boot is growing, we need to
2695establish some rules. Submissions which do not conform to these rules
2696may be rejected, even when they contain important and valuable stuff.
2697
2698
2699When you send a patch, please include the following information with
2700it:
2701
2702* For bug fixes: a description of the bug and how your patch fixes
2703 this bug. Please try to include a way of demonstrating that the
2704 patch actually fixes something.
2705
2706* For new features: a description of the feature and your
2707 implementation.
2708
2709* A CHANGELOG entry as plaintext (separate from the patch)
2710
2711* For major contributions, your entry to the CREDITS file
2712
2713* When you add support for a new board, don't forget to add this
2714 board to the MAKEALL script, too.
2715
2716* If your patch adds new configuration options, don't forget to
2717 document these in the README file.
2718
2719* The patch itself. If you are accessing the CVS repository use "cvs
2720 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2721 version of diff does not support these options, then get the latest
2722 version of GNU diff.
2723
2724 We accept patches as plain text, MIME attachments or as uuencoded
2725 gzipped text.
2726
2727Notes:
2728
2729* Before sending the patch, run the MAKEALL script on your patched
2730 source tree and make sure that no errors or warnings are reported
2731 for any of the boards.
2732
2733* Keep your modifications to the necessary minimum: A patch
2734 containing several unrelated changes or arbitrary reformats will be
2735 returned with a request to re-formatting / split it.
2736
2737* If you modify existing code, make sure that your new code does not
2738 add to the memory footprint of the code ;-) Small is beautiful!
2739 When adding new features, these should compile conditionally only
2740 (using #ifdef), and the resulting code with the new feature
2741 disabled must not need more memory than the old code without your
2742 modification.