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1 #
2 # (C) Copyright 2000 - 2004
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
24 Summary:
25 ========
26
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC and ARM processors, which can be
29 installed in a boot ROM and used to initialize and test the hardware
30 or to download and run application code.
31
32 The development of U-Boot is closely related to Linux: some parts of
33 the source code originate in the Linux source tree, we have some
34 header files in common, and special provision has been made to
35 support booting of Linux images.
36
37 Some attention has been paid to make this software easily
38 configurable and extendable. For instance, all monitor commands are
39 implemented with the same call interface, so that it's very easy to
40 add new commands. Also, instead of permanently adding rarely used
41 code (for instance hardware test utilities) to the monitor, you can
42 load and run it dynamically.
43
44
45 Status:
46 =======
47
48 In general, all boards for which a configuration option exists in the
49 Makefile have been tested to some extent and can be considered
50 "working". In fact, many of them are used in production systems.
51
52 In case of problems see the CHANGELOG and CREDITS files to find out
53 who contributed the specific port.
54
55
56 Where to get help:
57 ==================
58
59 In case you have questions about, problems with or contributions for
60 U-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
62 previous traffic on the mailing list - please search the archive
63 before asking FAQ's. Please see
64 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
65
66
67 Where we come from:
68 ===================
69
70 - start from 8xxrom sources
71 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
72 - clean up code
73 - make it easier to add custom boards
74 - make it possible to add other [PowerPC] CPUs
75 - extend functions, especially:
76 * Provide extended interface to Linux boot loader
77 * S-Record download
78 * network boot
79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80 - create ARMBoot project (http://sourceforge.net/projects/armboot)
81 - add other CPU families (starting with ARM)
82 - create U-Boot project (http://sourceforge.net/projects/u-boot)
83
84
85 Names and Spelling:
86 ===================
87
88 The "official" name of this project is "Das U-Boot". The spelling
89 "U-Boot" shall be used in all written text (documentation, comments
90 in source files etc.). Example:
91
92 This is the README file for the U-Boot project.
93
94 File 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
100 Variable names, preprocessor constants etc. shall be either based on
101 the string "u_boot" or on "U_BOOT". Example:
102
103 U_BOOT_VERSION u_boot_logo
104 IH_OS_U_BOOT u_boot_hush_start
105
106
107 Versioning:
108 ===========
109
110 U-Boot uses a 3 level version number containing a version, a
111 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112 sub-version "34", and patchlevel "4".
113
114 The patchlevel is used to indicate certain stages of development
115 between released versions, i. e. officially released versions of
116 U-Boot will always have a patchlevel of "0".
117
118
119 Directory Hierarchy:
120 ====================
121
122 - board Board dependent files
123 - common Misc architecture independent functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Commonly used device drivers
128 - dtt Digital Thermometer and Thermostat drivers
129 - examples Example code for standalone applications, etc.
130 - include Header Files
131 - disk Harddisk interface code
132 - net Networking code
133 - ppc Files generic to PowerPC architecture
134 - post Power On Self Test
135 - post/arch Symlink to architecture specific Power On Self Test
136 - post/arch-ppc PowerPC architecture specific Power On Self Test
137 - post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138 - post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139 - rtc Real Time Clock drivers
140 - tools Tools to build S-Record or U-Boot images, etc.
141
142 - cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
143 - cpu/arm925t Files specific to ARM 925 CPUs
144 - cpu/arm926ejs Files specific to ARM 926 CPUs
145 - cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
146 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
147 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
148 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
149 - cpu/mpc85xx Files specific to Motorola MPC85xx CPUs
150 - cpu/ppc4xx Files specific to IBM 4xx CPUs
151
152
153 - board/LEOX/ Files specific to boards manufactured by The LEOX team
154 - board/LEOX/elpt860 Files specific to ELPT860 boards
155 - board/RPXClassic
156 Files specific to RPXClassic boards
157 - board/RPXlite Files specific to RPXlite boards
158 - board/at91rm9200dk Files specific to AT91RM9200DK boards
159 - board/c2mon Files specific to c2mon boards
160 - board/cmi Files specific to cmi boards
161 - board/cogent Files specific to Cogent boards
162 (need further configuration)
163 Files specific to CPCIISER4 boards
164 - board/cpu86 Files specific to CPU86 boards
165 - board/cray/ Files specific to boards manufactured by Cray
166 - board/cray/L1 Files specific to L1 boards
167 - board/cu824 Files specific to CU824 boards
168 - board/ebony Files specific to IBM Ebony board
169 - board/eric Files specific to ERIC boards
170 - board/esd/ Files specific to boards manufactured by ESD
171 - board/esd/adciop Files specific to ADCIOP boards
172 - board/esd/ar405 Files specific to AR405 boards
173 - board/esd/canbt Files specific to CANBT boards
174 - board/esd/cpci405 Files specific to CPCI405 boards
175 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
176 - board/esd/common Common files for ESD boards
177 - board/esd/dasa_sim Files specific to DASA_SIM boards
178 - board/esd/du405 Files specific to DU405 boards
179 - board/esd/ocrtc Files specific to OCRTC boards
180 - board/esd/pci405 Files specific to PCI405 boards
181 - board/esteem192e
182 Files specific to ESTEEM192E boards
183 - board/etx094 Files specific to ETX_094 boards
184 - board/evb64260
185 Files specific to EVB64260 boards
186 - board/fads Files specific to FADS boards
187 - board/flagadm Files specific to FLAGADM boards
188 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
189 - board/genietv Files specific to GENIETV boards
190 - board/gth Files specific to GTH boards
191 - board/hermes Files specific to HERMES boards
192 - board/hymod Files specific to HYMOD boards
193 - board/icu862 Files specific to ICU862 boards
194 - board/ip860 Files specific to IP860 boards
195 - board/iphase4539
196 Files specific to Interphase4539 boards
197 - board/ivm Files specific to IVMS8/IVML24 boards
198 - board/lantec Files specific to LANTEC boards
199 - board/lwmon Files specific to LWMON boards
200 - board/Marvell Files specific to Marvell development boards
201 - board/Marvell/db64360 Files specific to db64360 board
202 - board/Marvell/db64460 Files specific to db64460 board
203 - board/mbx8xx Files specific to MBX boards
204 - board/mpc8260ads
205 Files specific to MPC826xADS and PQ2FADS-ZU/VR boards
206 - board/mpc8540ads
207 Files specific to MPC8540ADS boards
208 - board/mpc8560ads
209 Files specific to MPC8560ADS boards
210 - board/mpl/ Files specific to boards manufactured by MPL
211 - board/mpl/common Common files for MPL boards
212 - board/mpl/pip405 Files specific to PIP405 boards
213 - board/mpl/mip405 Files specific to MIP405 boards
214 - board/mpl/vcma9 Files specific to VCMA9 boards
215 - board/musenki Files specific to MUSEKNI boards
216 - board/mvs1 Files specific to MVS1 boards
217 - board/nx823 Files specific to NX823 boards
218 - board/oxc Files specific to OXC boards
219 - board/omap1510inn
220 Files specific to OMAP 1510 Innovator boards
221 - board/omap1610inn
222 Files specific to OMAP 1610 Innovator and H2 boards
223 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
224 - board/pm826 Files specific to PM826 boards
225 - board/ppmc8260
226 Files specific to PPMC8260 boards
227 - board/snmc/qs850 Files specific to QS850/823 boards
228 - board/snmc/qs860t Files specific to QS860T boards
229 - board/rpxsuper
230 Files specific to RPXsuper boards
231 - board/rsdproto
232 Files specific to RSDproto boards
233 - board/sandpoint
234 Files specific to Sandpoint boards
235 - board/sbc8260 Files specific to SBC8260 boards
236 - board/sacsng Files specific to SACSng boards
237 - board/siemens Files specific to boards manufactured by Siemens AG
238 - board/siemens/CCM Files specific to CCM boards
239 - board/siemens/IAD210 Files specific to IAD210 boards
240 - board/siemens/SCM Files specific to SCM boards
241 - board/siemens/pcu_e Files specific to PCU_E boards
242 - board/sixnet Files specific to SIXNET boards
243 - board/spd8xx Files specific to SPD8xxTS boards
244 - board/tqm8260 Files specific to TQM8260 boards
245 - board/tqm8xx Files specific to TQM8xxL boards
246 - board/w7o Files specific to W7O boards
247 - board/walnut405
248 Files specific to Walnut405 boards
249 - board/westel/ Files specific to boards manufactured by Westel Wireless
250 - board/westel/amx860 Files specific to AMX860 boards
251 - board/utx8245 Files specific to UTX8245 boards
252 - board/zpc1900 Files specific to Zephyr Engineering ZPC.1900 board
253
254 Software Configuration:
255 =======================
256
257 Configuration is usually done using C preprocessor defines; the
258 rationale behind that is to avoid dead code whenever possible.
259
260 There are two classes of configuration variables:
261
262 * Configuration _OPTIONS_:
263 These are selectable by the user and have names beginning with
264 "CONFIG_".
265
266 * Configuration _SETTINGS_:
267 These depend on the hardware etc. and should not be meddled with if
268 you don't know what you're doing; they have names beginning with
269 "CFG_".
270
271 Later we will add a configuration tool - probably similar to or even
272 identical to what's used for the Linux kernel. Right now, we have to
273 do the configuration by hand, which means creating some symbolic
274 links and editing some configuration files. We use the TQM8xxL boards
275 as an example here.
276
277
278 Selection of Processor Architecture and Board Type:
279 ---------------------------------------------------
280
281 For all supported boards there are ready-to-use default
282 configurations available; just type "make <board_name>_config".
283
284 Example: For a TQM823L module type:
285
286 cd u-boot
287 make TQM823L_config
288
289 For the Cogent platform, you need to specify the cpu type as well;
290 e.g. "make cogent_mpc8xx_config". And also configure the cogent
291 directory according to the instructions in cogent/README.
292
293
294 Configuration Options:
295 ----------------------
296
297 Configuration depends on the combination of board and CPU type; all
298 such information is kept in a configuration file
299 "include/configs/<board_name>.h".
300
301 Example: For a TQM823L module, all configuration settings are in
302 "include/configs/TQM823L.h".
303
304
305 Many of the options are named exactly as the corresponding Linux
306 kernel configuration options. The intention is to make it easier to
307 build a config tool - later.
308
309
310 The following options need to be configured:
311
312 - CPU Type: Define exactly one of
313
314 PowerPC based CPUs:
315 -------------------
316 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
317 or CONFIG_MPC5xx
318 or CONFIG_MPC824X, CONFIG_MPC8260
319 or CONFIG_MPC85xx
320 or CONFIG_IOP480
321 or CONFIG_405GP
322 or CONFIG_405EP
323 or CONFIG_440
324 or CONFIG_MPC74xx
325 or CONFIG_750FX
326
327 ARM based CPUs:
328 ---------------
329 CONFIG_SA1110
330 CONFIG_ARM7
331 CONFIG_PXA250
332
333
334 - Board Type: Define exactly one of
335
336 PowerPC based boards:
337 ---------------------
338
339 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
340 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
341 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
342 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
343 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
344 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
345 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
346 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
347 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
348 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
349 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
350 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
351 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
352 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
353 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
354 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
355 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
356 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
357 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
358 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
359 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
360 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
361 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
362 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
363 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
364 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
365 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
366 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
367 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
368 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
369 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
370 CONFIG_NETVIA, CONFIG_RBC823, CONFIG_ZPC1900,
371 CONFIG_MPC8540ADS, CONFIG_MPC8560ADS, CONFIG_QS850,
372 CONFIG_QS823, CONFIG_QS860T, CONFIG_DB64360,
373 CONFIG_DB64460, CONFIG_DUET_ADS
374
375 ARM based boards:
376 -----------------
377
378 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
379 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
380 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
381 CONFIG_H2_OMAP1610, CONFIG_SHANNON, CONFIG_SMDK2400,
382 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9,
383 CONFIG_AT91RM9200DK
384
385
386 - CPU Module Type: (if CONFIG_COGENT is defined)
387 Define exactly one of
388 CONFIG_CMA286_60_OLD
389 --- FIXME --- not tested yet:
390 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
391 CONFIG_CMA287_23, CONFIG_CMA287_50
392
393 - Motherboard Type: (if CONFIG_COGENT is defined)
394 Define exactly one of
395 CONFIG_CMA101, CONFIG_CMA102
396
397 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
398 Define one or more of
399 CONFIG_CMA302
400
401 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
402 Define one or more of
403 CONFIG_LCD_HEARTBEAT - update a character position on
404 the lcd display every second with
405 a "rotator" |\-/|\-/
406
407 - Board flavour: (if CONFIG_MPC8260ADS is defined)
408 CONFIG_ADSTYPE
409 Possible values are:
410 CFG_8260ADS - original MPC8260ADS
411 CFG_8266ADS - MPC8266ADS
412 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
413
414
415 - MPC824X Family Member (if CONFIG_MPC824X is defined)
416 Define exactly one of
417 CONFIG_MPC8240, CONFIG_MPC8245
418
419 - 8xx CPU Options: (if using an MPC8xx cpu)
420 Define one or more of
421 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work
422 e.g. if there is no 32KHz
423 reference PIT/RTC clock
424
425 - 859/866 CPU options: (if using a MPC859 or MPC866 CPU):
426 CFG_866_OSCCLK
427 CFG_866_CPUCLK_MIN
428 CFG_866_CPUCLK_MAX
429 CFG_866_CPUCLK_DEFAULT
430 See doc/README.MPC866
431
432 CFG_MEASURE_CPUCLK
433
434 Define this to measure the actual CPU clock instead
435 of relying on the correctness of the configured
436 values. Mostly useful for board bringup to make sure
437 the PLL is locked at the intended frequency. Note
438 that this requires a (stable) reference clock (32 kHz
439 RTC clock),
440
441 - Linux Kernel Interface:
442 CONFIG_CLOCKS_IN_MHZ
443
444 U-Boot stores all clock information in Hz
445 internally. For binary compatibility with older Linux
446 kernels (which expect the clocks passed in the
447 bd_info data to be in MHz) the environment variable
448 "clocks_in_mhz" can be defined so that U-Boot
449 converts clock data to MHZ before passing it to the
450 Linux kernel.
451 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
452 "clocks_in_mhz=1" is automatically included in the
453 default environment.
454
455 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
456
457 When transfering memsize parameter to linux, some versions
458 expect it to be in bytes, others in MB.
459 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
460
461 - Console Interface:
462 Depending on board, define exactly one serial port
463 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
464 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
465 console by defining CONFIG_8xx_CONS_NONE
466
467 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
468 port routines must be defined elsewhere
469 (i.e. serial_init(), serial_getc(), ...)
470
471 CONFIG_CFB_CONSOLE
472 Enables console device for a color framebuffer. Needs following
473 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
474 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
475 (default big endian)
476 VIDEO_HW_RECTFILL graphic chip supports
477 rectangle fill
478 (cf. smiLynxEM)
479 VIDEO_HW_BITBLT graphic chip supports
480 bit-blit (cf. smiLynxEM)
481 VIDEO_VISIBLE_COLS visible pixel columns
482 (cols=pitch)
483 VIDEO_VISIBLE_ROWS visible pixel rows
484 VIDEO_PIXEL_SIZE bytes per pixel
485 VIDEO_DATA_FORMAT graphic data format
486 (0-5, cf. cfb_console.c)
487 VIDEO_FB_ADRS framebuffer address
488 VIDEO_KBD_INIT_FCT keyboard int fct
489 (i.e. i8042_kbd_init())
490 VIDEO_TSTC_FCT test char fct
491 (i.e. i8042_tstc)
492 VIDEO_GETC_FCT get char fct
493 (i.e. i8042_getc)
494 CONFIG_CONSOLE_CURSOR cursor drawing on/off
495 (requires blink timer
496 cf. i8042.c)
497 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
498 CONFIG_CONSOLE_TIME display time/date info in
499 upper right corner
500 (requires CFG_CMD_DATE)
501 CONFIG_VIDEO_LOGO display Linux logo in
502 upper left corner
503 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
504 linux_logo.h for logo.
505 Requires CONFIG_VIDEO_LOGO
506 CONFIG_CONSOLE_EXTRA_INFO
507 addional board info beside
508 the logo
509
510 When CONFIG_CFB_CONSOLE is defined, video console is
511 default i/o. Serial console can be forced with
512 environment 'console=serial'.
513
514 When CONFIG_SILENT_CONSOLE is defined, all console
515 messages (by U-Boot and Linux!) can be silenced with
516 the "silent" environment variable. See
517 doc/README.silent for more information.
518
519 - Console Baudrate:
520 CONFIG_BAUDRATE - in bps
521 Select one of the baudrates listed in
522 CFG_BAUDRATE_TABLE, see below.
523 CFG_BRGCLK_PRESCALE, baudrate prescale
524
525 - Interrupt driven serial port input:
526 CONFIG_SERIAL_SOFTWARE_FIFO
527
528 PPC405GP only.
529 Use an interrupt handler for receiving data on the
530 serial port. It also enables using hardware handshake
531 (RTS/CTS) and UART's built-in FIFO. Set the number of
532 bytes the interrupt driven input buffer should have.
533
534 Set to 0 to disable this feature (this is the default).
535 This will also disable hardware handshake.
536
537 - Console UART Number:
538 CONFIG_UART1_CONSOLE
539
540 IBM PPC4xx only.
541 If defined internal UART1 (and not UART0) is used
542 as default U-Boot console.
543
544 - Boot Delay: CONFIG_BOOTDELAY - in seconds
545 Delay before automatically booting the default image;
546 set to -1 to disable autoboot.
547
548 See doc/README.autoboot for these options that
549 work with CONFIG_BOOTDELAY. None are required.
550 CONFIG_BOOT_RETRY_TIME
551 CONFIG_BOOT_RETRY_MIN
552 CONFIG_AUTOBOOT_KEYED
553 CONFIG_AUTOBOOT_PROMPT
554 CONFIG_AUTOBOOT_DELAY_STR
555 CONFIG_AUTOBOOT_STOP_STR
556 CONFIG_AUTOBOOT_DELAY_STR2
557 CONFIG_AUTOBOOT_STOP_STR2
558 CONFIG_ZERO_BOOTDELAY_CHECK
559 CONFIG_RESET_TO_RETRY
560
561 - Autoboot Command:
562 CONFIG_BOOTCOMMAND
563 Only needed when CONFIG_BOOTDELAY is enabled;
564 define a command string that is automatically executed
565 when no character is read on the console interface
566 within "Boot Delay" after reset.
567
568 CONFIG_BOOTARGS
569 This can be used to pass arguments to the bootm
570 command. The value of CONFIG_BOOTARGS goes into the
571 environment value "bootargs".
572
573 CONFIG_RAMBOOT and CONFIG_NFSBOOT
574 The value of these goes into the environment as
575 "ramboot" and "nfsboot" respectively, and can be used
576 as a convenience, when switching between booting from
577 ram and nfs.
578
579 - Pre-Boot Commands:
580 CONFIG_PREBOOT
581
582 When this option is #defined, the existence of the
583 environment variable "preboot" will be checked
584 immediately before starting the CONFIG_BOOTDELAY
585 countdown and/or running the auto-boot command resp.
586 entering interactive mode.
587
588 This feature is especially useful when "preboot" is
589 automatically generated or modified. For an example
590 see the LWMON board specific code: here "preboot" is
591 modified when the user holds down a certain
592 combination of keys on the (special) keyboard when
593 booting the systems
594
595 - Serial Download Echo Mode:
596 CONFIG_LOADS_ECHO
597 If defined to 1, all characters received during a
598 serial download (using the "loads" command) are
599 echoed back. This might be needed by some terminal
600 emulations (like "cu"), but may as well just take
601 time on others. This setting #define's the initial
602 value of the "loads_echo" environment variable.
603
604 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
605 CONFIG_KGDB_BAUDRATE
606 Select one of the baudrates listed in
607 CFG_BAUDRATE_TABLE, see below.
608
609 - Monitor Functions:
610 CONFIG_COMMANDS
611 Most monitor functions can be selected (or
612 de-selected) by adjusting the definition of
613 CONFIG_COMMANDS; to select individual functions,
614 #define CONFIG_COMMANDS by "OR"ing any of the
615 following values:
616
617 #define enables commands:
618 -------------------------
619 CFG_CMD_ASKENV * ask for env variable
620 CFG_CMD_AUTOSCRIPT Autoscript Support
621 CFG_CMD_BDI bdinfo
622 CFG_CMD_BEDBUG Include BedBug Debugger
623 CFG_CMD_BMP * BMP support
624 CFG_CMD_BOOTD bootd
625 CFG_CMD_CACHE icache, dcache
626 CFG_CMD_CONSOLE coninfo
627 CFG_CMD_DATE * support for RTC, date/time...
628 CFG_CMD_DHCP DHCP support
629 CFG_CMD_DIAG * Diagnostics
630 CFG_CMD_DOC * Disk-On-Chip Support
631 CFG_CMD_DTT Digital Therm and Thermostat
632 CFG_CMD_ECHO * echo arguments
633 CFG_CMD_EEPROM * EEPROM read/write support
634 CFG_CMD_ELF bootelf, bootvx
635 CFG_CMD_ENV saveenv
636 CFG_CMD_FDC * Floppy Disk Support
637 CFG_CMD_FAT FAT partition support
638 CFG_CMD_FDOS * Dos diskette Support
639 CFG_CMD_FLASH flinfo, erase, protect
640 CFG_CMD_FPGA FPGA device initialization support
641 CFG_CMD_HWFLOW * RTS/CTS hw flow control
642 CFG_CMD_I2C * I2C serial bus support
643 CFG_CMD_IDE * IDE harddisk support
644 CFG_CMD_IMI iminfo
645 CFG_CMD_IMLS List all found images
646 CFG_CMD_IMMAP * IMMR dump support
647 CFG_CMD_IRQ * irqinfo
648 CFG_CMD_ITEST * Integer/string test of 2 values
649 CFG_CMD_JFFS2 * JFFS2 Support
650 CFG_CMD_KGDB * kgdb
651 CFG_CMD_LOADB loadb
652 CFG_CMD_LOADS loads
653 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
654 loop, mtest
655 CFG_CMD_MISC Misc functions like sleep etc
656 CFG_CMD_MMC MMC memory mapped support
657 CFG_CMD_MII MII utility commands
658 CFG_CMD_NAND * NAND support
659 CFG_CMD_NET bootp, tftpboot, rarpboot
660 CFG_CMD_PCI * pciinfo
661 CFG_CMD_PCMCIA * PCMCIA support
662 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
663 CFG_CMD_PORTIO * Port I/O
664 CFG_CMD_REGINFO * Register dump
665 CFG_CMD_RUN run command in env variable
666 CFG_CMD_SAVES save S record dump
667 CFG_CMD_SCSI * SCSI Support
668 CFG_CMD_SDRAM * print SDRAM configuration information
669 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
670 CFG_CMD_SPI * SPI serial bus support
671 CFG_CMD_USB * USB support
672 CFG_CMD_VFD * VFD support (TRAB)
673 CFG_CMD_BSP * Board SPecific functions
674 -----------------------------------------------
675 CFG_CMD_ALL all
676
677 CFG_CMD_DFL Default configuration; at the moment
678 this is includes all commands, except
679 the ones marked with "*" in the list
680 above.
681
682 If you don't define CONFIG_COMMANDS it defaults to
683 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
684 override the default settings in the respective
685 include file.
686
687 EXAMPLE: If you want all functions except of network
688 support you can write:
689
690 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
691
692
693 Note: Don't enable the "icache" and "dcache" commands
694 (configuration option CFG_CMD_CACHE) unless you know
695 what you (and your U-Boot users) are doing. Data
696 cache cannot be enabled on systems like the 8xx or
697 8260 (where accesses to the IMMR region must be
698 uncached), and it cannot be disabled on all other
699 systems where we (mis-) use the data cache to hold an
700 initial stack and some data.
701
702
703 XXX - this list needs to get updated!
704
705 - Watchdog:
706 CONFIG_WATCHDOG
707 If this variable is defined, it enables watchdog
708 support. There must be support in the platform specific
709 code for a watchdog. For the 8xx and 8260 CPUs, the
710 SIU Watchdog feature is enabled in the SYPCR
711 register.
712
713 - U-Boot Version:
714 CONFIG_VERSION_VARIABLE
715 If this variable is defined, an environment variable
716 named "ver" is created by U-Boot showing the U-Boot
717 version as printed by the "version" command.
718 This variable is readonly.
719
720 - Real-Time Clock:
721
722 When CFG_CMD_DATE is selected, the type of the RTC
723 has to be selected, too. Define exactly one of the
724 following options:
725
726 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
727 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
728 CONFIG_RTC_MC146818 - use MC146818 RTC
729 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
730 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
731 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
732 CONFIG_RTC_DS164x - use Dallas DS164x RTC
733
734 Note that if the RTC uses I2C, then the I2C interface
735 must also be configured. See I2C Support, below.
736
737 - Timestamp Support:
738
739 When CONFIG_TIMESTAMP is selected, the timestamp
740 (date and time) of an image is printed by image
741 commands like bootm or iminfo. This option is
742 automatically enabled when you select CFG_CMD_DATE .
743
744 - Partition Support:
745 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
746 and/or CONFIG_ISO_PARTITION
747
748 If IDE or SCSI support is enabled (CFG_CMD_IDE or
749 CFG_CMD_SCSI) you must configure support for at least
750 one partition type as well.
751
752 - IDE Reset method:
753 CONFIG_IDE_RESET_ROUTINE
754
755 Set this to define that instead of a reset Pin, the
756 routine ide_set_reset(int idereset) will be used.
757
758 - ATAPI Support:
759 CONFIG_ATAPI
760
761 Set this to enable ATAPI support.
762
763 - SCSI Support:
764 At the moment only there is only support for the
765 SYM53C8XX SCSI controller; define
766 CONFIG_SCSI_SYM53C8XX to enable it.
767
768 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
769 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
770 CFG_SCSI_MAX_LUN] can be adjusted to define the
771 maximum numbers of LUNs, SCSI ID's and target
772 devices.
773 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
774
775 - NETWORK Support (PCI):
776 CONFIG_E1000
777 Support for Intel 8254x gigabit chips.
778
779 CONFIG_EEPRO100
780 Support for Intel 82557/82559/82559ER chips.
781 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
782 write routine for first time initialisation.
783
784 CONFIG_TULIP
785 Support for Digital 2114x chips.
786 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
787 modem chip initialisation (KS8761/QS6611).
788
789 CONFIG_NATSEMI
790 Support for National dp83815 chips.
791
792 CONFIG_NS8382X
793 Support for National dp8382[01] gigabit chips.
794
795 - NETWORK Support (other):
796
797 CONFIG_DRIVER_LAN91C96
798 Support for SMSC's LAN91C96 chips.
799
800 CONFIG_LAN91C96_BASE
801 Define this to hold the physical address
802 of the LAN91C96's I/O space
803
804 CONFIG_LAN91C96_USE_32_BIT
805 Define this to enable 32 bit addressing
806
807 - USB Support:
808 At the moment only the UHCI host controller is
809 supported (PIP405, MIP405); define
810 CONFIG_USB_UHCI to enable it.
811 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
812 end define CONFIG_USB_STORAGE to enable the USB
813 storage devices.
814 Note:
815 Supported are USB Keyboards and USB Floppy drives
816 (TEAC FD-05PUB).
817
818 - MMC Support:
819 The MMC controller on the Intel PXA is supported. To
820 enable this define CONFIG_MMC. The MMC can be
821 accessed from the boot prompt by mapping the device
822 to physical memory similar to flash. Command line is
823 enabled with CFG_CMD_MMC. The MMC driver also works with
824 the FAT fs. This is enabled with CFG_CMD_FAT.
825
826 - Keyboard Support:
827 CONFIG_ISA_KEYBOARD
828
829 Define this to enable standard (PC-Style) keyboard
830 support
831
832 CONFIG_I8042_KBD
833 Standard PC keyboard driver with US (is default) and
834 GERMAN key layout (switch via environment 'keymap=de') support.
835 Export function i8042_kbd_init, i8042_tstc and i8042_getc
836 for cfb_console. Supports cursor blinking.
837
838 - Video support:
839 CONFIG_VIDEO
840
841 Define this to enable video support (for output to
842 video).
843
844 CONFIG_VIDEO_CT69000
845
846 Enable Chips & Technologies 69000 Video chip
847
848 CONFIG_VIDEO_SMI_LYNXEM
849 Enable Silicon Motion SMI 712/710/810 Video chip
850 Videomode are selected via environment 'videomode' with
851 standard LiLo mode numbers.
852 Following modes are supported (* is default):
853
854 800x600 1024x768 1280x1024
855 256 (8bit) 303* 305 307
856 65536 (16bit) 314 317 31a
857 16,7 Mill (24bit) 315 318 31b
858 (i.e. setenv videomode 317; saveenv; reset;)
859
860 CONFIG_VIDEO_SED13806
861 Enable Epson SED13806 driver. This driver supports 8bpp
862 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
863 or CONFIG_VIDEO_SED13806_16BPP
864
865 - Keyboard Support:
866 CONFIG_KEYBOARD
867
868 Define this to enable a custom keyboard support.
869 This simply calls drv_keyboard_init() which must be
870 defined in your board-specific files.
871 The only board using this so far is RBC823.
872
873 - LCD Support: CONFIG_LCD
874
875 Define this to enable LCD support (for output to LCD
876 display); also select one of the supported displays
877 by defining one of these:
878
879 CONFIG_NEC_NL6448AC33:
880
881 NEC NL6448AC33-18. Active, color, single scan.
882
883 CONFIG_NEC_NL6448BC20
884
885 NEC NL6448BC20-08. 6.5", 640x480.
886 Active, color, single scan.
887
888 CONFIG_NEC_NL6448BC33_54
889
890 NEC NL6448BC33-54. 10.4", 640x480.
891 Active, color, single scan.
892
893 CONFIG_SHARP_16x9
894
895 Sharp 320x240. Active, color, single scan.
896 It isn't 16x9, and I am not sure what it is.
897
898 CONFIG_SHARP_LQ64D341
899
900 Sharp LQ64D341 display, 640x480.
901 Active, color, single scan.
902
903 CONFIG_HLD1045
904
905 HLD1045 display, 640x480.
906 Active, color, single scan.
907
908 CONFIG_OPTREX_BW
909
910 Optrex CBL50840-2 NF-FW 99 22 M5
911 or
912 Hitachi LMG6912RPFC-00T
913 or
914 Hitachi SP14Q002
915
916 320x240. Black & white.
917
918 Normally display is black on white background; define
919 CFG_WHITE_ON_BLACK to get it inverted.
920
921 - Splash Screen Support: CONFIG_SPLASH_SCREEN
922
923 If this option is set, the environment is checked for
924 a variable "splashimage". If found, the usual display
925 of logo, copyright and system information on the LCD
926 is supressed and the BMP image at the address
927 specified in "splashimage" is loaded instead. The
928 console is redirected to the "nulldev", too. This
929 allows for a "silent" boot where a splash screen is
930 loaded very quickly after power-on.
931
932 - Compression support:
933 CONFIG_BZIP2
934
935 If this option is set, support for bzip2 compressed
936 images is included. If not, only uncompressed and gzip
937 compressed images are supported.
938
939 NOTE: the bzip2 algorithm requires a lot of RAM, so
940 the malloc area (as defined by CFG_MALLOC_LEN) should
941 be at least 4MB.
942
943 - Ethernet address:
944 CONFIG_ETHADDR
945 CONFIG_ETH2ADDR
946 CONFIG_ETH3ADDR
947
948 Define a default value for ethernet address to use
949 for the respective ethernet interface, in case this
950 is not determined automatically.
951
952 - IP address:
953 CONFIG_IPADDR
954
955 Define a default value for the IP address to use for
956 the default ethernet interface, in case this is not
957 determined through e.g. bootp.
958
959 - Server IP address:
960 CONFIG_SERVERIP
961
962 Defines a default value for theIP address of a TFTP
963 server to contact when using the "tftboot" command.
964
965 - BOOTP Recovery Mode:
966 CONFIG_BOOTP_RANDOM_DELAY
967
968 If you have many targets in a network that try to
969 boot using BOOTP, you may want to avoid that all
970 systems send out BOOTP requests at precisely the same
971 moment (which would happen for instance at recovery
972 from a power failure, when all systems will try to
973 boot, thus flooding the BOOTP server. Defining
974 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
975 inserted before sending out BOOTP requests. The
976 following delays are insterted then:
977
978 1st BOOTP request: delay 0 ... 1 sec
979 2nd BOOTP request: delay 0 ... 2 sec
980 3rd BOOTP request: delay 0 ... 4 sec
981 4th and following
982 BOOTP requests: delay 0 ... 8 sec
983
984 - DHCP Advanced Options:
985 CONFIG_BOOTP_MASK
986
987 You can fine tune the DHCP functionality by adding
988 these flags to the CONFIG_BOOTP_MASK define:
989
990 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
991 serverip from a DHCP server, it is possible that more
992 than one DNS serverip is offered to the client.
993 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
994 serverip will be stored in the additional environment
995 variable "dnsip2". The first DNS serverip is always
996 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
997 is added to the CONFIG_BOOTP_MASK.
998
999 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1000 to do a dynamic update of a DNS server. To do this, they
1001 need the hostname of the DHCP requester.
1002 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1003 CONFIG_BOOTP_MASK, the content of the "hostname"
1004 environment variable is passed as option 12 to
1005 the DHCP server.
1006
1007 - Status LED: CONFIG_STATUS_LED
1008
1009 Several configurations allow to display the current
1010 status using a LED. For instance, the LED will blink
1011 fast while running U-Boot code, stop blinking as
1012 soon as a reply to a BOOTP request was received, and
1013 start blinking slow once the Linux kernel is running
1014 (supported by a status LED driver in the Linux
1015 kernel). Defining CONFIG_STATUS_LED enables this
1016 feature in U-Boot.
1017
1018 - CAN Support: CONFIG_CAN_DRIVER
1019
1020 Defining CONFIG_CAN_DRIVER enables CAN driver support
1021 on those systems that support this (optional)
1022 feature, like the TQM8xxL modules.
1023
1024 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1025
1026 These enable I2C serial bus commands. Defining either of
1027 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1028 include the appropriate I2C driver for the selected cpu.
1029
1030 This will allow you to use i2c commands at the u-boot
1031 command line (as long as you set CFG_CMD_I2C in
1032 CONFIG_COMMANDS) and communicate with i2c based realtime
1033 clock chips. See common/cmd_i2c.c for a description of the
1034 command line interface.
1035
1036 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
1037
1038 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1039 bit-banging) driver instead of CPM or similar hardware
1040 support for I2C.
1041
1042 There are several other quantities that must also be
1043 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1044
1045 In both cases you will need to define CFG_I2C_SPEED
1046 to be the frequency (in Hz) at which you wish your i2c bus
1047 to run and CFG_I2C_SLAVE to be the address of this node (ie
1048 the cpu's i2c node address).
1049
1050 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1051 sets the cpu up as a master node and so its address should
1052 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1053 p.16-473). So, set CFG_I2C_SLAVE to 0.
1054
1055 That's all that's required for CONFIG_HARD_I2C.
1056
1057 If you use the software i2c interface (CONFIG_SOFT_I2C)
1058 then the following macros need to be defined (examples are
1059 from include/configs/lwmon.h):
1060
1061 I2C_INIT
1062
1063 (Optional). Any commands necessary to enable the I2C
1064 controller or configure ports.
1065
1066 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1067
1068 I2C_PORT
1069
1070 (Only for MPC8260 CPU). The I/O port to use (the code
1071 assumes both bits are on the same port). Valid values
1072 are 0..3 for ports A..D.
1073
1074 I2C_ACTIVE
1075
1076 The code necessary to make the I2C data line active
1077 (driven). If the data line is open collector, this
1078 define can be null.
1079
1080 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1081
1082 I2C_TRISTATE
1083
1084 The code necessary to make the I2C data line tri-stated
1085 (inactive). If the data line is open collector, this
1086 define can be null.
1087
1088 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1089
1090 I2C_READ
1091
1092 Code that returns TRUE if the I2C data line is high,
1093 FALSE if it is low.
1094
1095 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1096
1097 I2C_SDA(bit)
1098
1099 If <bit> is TRUE, sets the I2C data line high. If it
1100 is FALSE, it clears it (low).
1101
1102 eg: #define I2C_SDA(bit) \
1103 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1104 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1105
1106 I2C_SCL(bit)
1107
1108 If <bit> is TRUE, sets the I2C clock line high. If it
1109 is FALSE, it clears it (low).
1110
1111 eg: #define I2C_SCL(bit) \
1112 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1113 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1114
1115 I2C_DELAY
1116
1117 This delay is invoked four times per clock cycle so this
1118 controls the rate of data transfer. The data rate thus
1119 is 1 / (I2C_DELAY * 4). Often defined to be something
1120 like:
1121
1122 #define I2C_DELAY udelay(2)
1123
1124 CFG_I2C_INIT_BOARD
1125
1126 When a board is reset during an i2c bus transfer
1127 chips might think that the current transfer is still
1128 in progress. On some boards it is possible to access
1129 the i2c SCLK line directly, either by using the
1130 processor pin as a GPIO or by having a second pin
1131 connected to the bus. If this option is defined a
1132 custom i2c_init_board() routine in boards/xxx/board.c
1133 is run early in the boot sequence.
1134
1135 - SPI Support: CONFIG_SPI
1136
1137 Enables SPI driver (so far only tested with
1138 SPI EEPROM, also an instance works with Crystal A/D and
1139 D/As on the SACSng board)
1140
1141 CONFIG_SPI_X
1142
1143 Enables extended (16-bit) SPI EEPROM addressing.
1144 (symmetrical to CONFIG_I2C_X)
1145
1146 CONFIG_SOFT_SPI
1147
1148 Enables a software (bit-bang) SPI driver rather than
1149 using hardware support. This is a general purpose
1150 driver that only requires three general I/O port pins
1151 (two outputs, one input) to function. If this is
1152 defined, the board configuration must define several
1153 SPI configuration items (port pins to use, etc). For
1154 an example, see include/configs/sacsng.h.
1155
1156 - FPGA Support: CONFIG_FPGA_COUNT
1157
1158 Specify the number of FPGA devices to support.
1159
1160 CONFIG_FPGA
1161
1162 Used to specify the types of FPGA devices. For
1163 example,
1164 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1165
1166 CFG_FPGA_PROG_FEEDBACK
1167
1168 Enable printing of hash marks during FPGA
1169 configuration.
1170
1171 CFG_FPGA_CHECK_BUSY
1172
1173 Enable checks on FPGA configuration interface busy
1174 status by the configuration function. This option
1175 will require a board or device specific function to
1176 be written.
1177
1178 CONFIG_FPGA_DELAY
1179
1180 If defined, a function that provides delays in the
1181 FPGA configuration driver.
1182
1183 CFG_FPGA_CHECK_CTRLC
1184
1185 Allow Control-C to interrupt FPGA configuration
1186
1187 CFG_FPGA_CHECK_ERROR
1188
1189 Check for configuration errors during FPGA bitfile
1190 loading. For example, abort during Virtex II
1191 configuration if the INIT_B line goes low (which
1192 indicated a CRC error).
1193
1194 CFG_FPGA_WAIT_INIT
1195
1196 Maximum time to wait for the INIT_B line to deassert
1197 after PROB_B has been deasserted during a Virtex II
1198 FPGA configuration sequence. The default time is 500 mS.
1199
1200 CFG_FPGA_WAIT_BUSY
1201
1202 Maximum time to wait for BUSY to deassert during
1203 Virtex II FPGA configuration. The default is 5 mS.
1204
1205 CFG_FPGA_WAIT_CONFIG
1206
1207 Time to wait after FPGA configuration. The default is
1208 200 mS.
1209
1210 - FPGA Support: CONFIG_FPGA_COUNT
1211
1212 Specify the number of FPGA devices to support.
1213
1214 CONFIG_FPGA
1215
1216 Used to specify the types of FPGA devices. For example,
1217 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1218
1219 CFG_FPGA_PROG_FEEDBACK
1220
1221 Enable printing of hash marks during FPGA configuration.
1222
1223 CFG_FPGA_CHECK_BUSY
1224
1225 Enable checks on FPGA configuration interface busy
1226 status by the configuration function. This option
1227 will require a board or device specific function to
1228 be written.
1229
1230 CONFIG_FPGA_DELAY
1231
1232 If defined, a function that provides delays in the FPGA
1233 configuration driver.
1234
1235 CFG_FPGA_CHECK_CTRLC
1236 Allow Control-C to interrupt FPGA configuration
1237
1238 CFG_FPGA_CHECK_ERROR
1239
1240 Check for configuration errors during FPGA bitfile
1241 loading. For example, abort during Virtex II
1242 configuration if the INIT_B line goes low (which
1243 indicated a CRC error).
1244
1245 CFG_FPGA_WAIT_INIT
1246
1247 Maximum time to wait for the INIT_B line to deassert
1248 after PROB_B has been deasserted during a Virtex II
1249 FPGA configuration sequence. The default time is 500
1250 mS.
1251
1252 CFG_FPGA_WAIT_BUSY
1253
1254 Maximum time to wait for BUSY to deassert during
1255 Virtex II FPGA configuration. The default is 5 mS.
1256
1257 CFG_FPGA_WAIT_CONFIG
1258
1259 Time to wait after FPGA configuration. The default is
1260 200 mS.
1261
1262 - Configuration Management:
1263 CONFIG_IDENT_STRING
1264
1265 If defined, this string will be added to the U-Boot
1266 version information (U_BOOT_VERSION)
1267
1268 - Vendor Parameter Protection:
1269
1270 U-Boot considers the values of the environment
1271 variables "serial#" (Board Serial Number) and
1272 "ethaddr" (Ethernet Address) to be parameters that
1273 are set once by the board vendor / manufacturer, and
1274 protects these variables from casual modification by
1275 the user. Once set, these variables are read-only,
1276 and write or delete attempts are rejected. You can
1277 change this behviour:
1278
1279 If CONFIG_ENV_OVERWRITE is #defined in your config
1280 file, the write protection for vendor parameters is
1281 completely disabled. Anybody can change or delete
1282 these parameters.
1283
1284 Alternatively, if you #define _both_ CONFIG_ETHADDR
1285 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1286 ethernet address is installed in the environment,
1287 which can be changed exactly ONCE by the user. [The
1288 serial# is unaffected by this, i. e. it remains
1289 read-only.]
1290
1291 - Protected RAM:
1292 CONFIG_PRAM
1293
1294 Define this variable to enable the reservation of
1295 "protected RAM", i. e. RAM which is not overwritten
1296 by U-Boot. Define CONFIG_PRAM to hold the number of
1297 kB you want to reserve for pRAM. You can overwrite
1298 this default value by defining an environment
1299 variable "pram" to the number of kB you want to
1300 reserve. Note that the board info structure will
1301 still show the full amount of RAM. If pRAM is
1302 reserved, a new environment variable "mem" will
1303 automatically be defined to hold the amount of
1304 remaining RAM in a form that can be passed as boot
1305 argument to Linux, for instance like that:
1306
1307 setenv bootargs ... mem=\$(mem)
1308 saveenv
1309
1310 This way you can tell Linux not to use this memory,
1311 either, which results in a memory region that will
1312 not be affected by reboots.
1313
1314 *WARNING* If your board configuration uses automatic
1315 detection of the RAM size, you must make sure that
1316 this memory test is non-destructive. So far, the
1317 following board configurations are known to be
1318 "pRAM-clean":
1319
1320 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1321 HERMES, IP860, RPXlite, LWMON, LANTEC,
1322 PCU_E, FLAGADM, TQM8260
1323
1324 - Error Recovery:
1325 CONFIG_PANIC_HANG
1326
1327 Define this variable to stop the system in case of a
1328 fatal error, so that you have to reset it manually.
1329 This is probably NOT a good idea for an embedded
1330 system where you want to system to reboot
1331 automatically as fast as possible, but it may be
1332 useful during development since you can try to debug
1333 the conditions that lead to the situation.
1334
1335 CONFIG_NET_RETRY_COUNT
1336
1337 This variable defines the number of retries for
1338 network operations like ARP, RARP, TFTP, or BOOTP
1339 before giving up the operation. If not defined, a
1340 default value of 5 is used.
1341
1342 - Command Interpreter:
1343 CFG_HUSH_PARSER
1344
1345 Define this variable to enable the "hush" shell (from
1346 Busybox) as command line interpreter, thus enabling
1347 powerful command line syntax like
1348 if...then...else...fi conditionals or `&&' and '||'
1349 constructs ("shell scripts").
1350
1351 If undefined, you get the old, much simpler behaviour
1352 with a somewhat smaller memory footprint.
1353
1354
1355 CFG_PROMPT_HUSH_PS2
1356
1357 This defines the secondary prompt string, which is
1358 printed when the command interpreter needs more input
1359 to complete a command. Usually "> ".
1360
1361 Note:
1362
1363 In the current implementation, the local variables
1364 space and global environment variables space are
1365 separated. Local variables are those you define by
1366 simply typing `name=value'. To access a local
1367 variable later on, you have write `$name' or
1368 `${name}'; to execute the contents of a variable
1369 directly type `$name' at the command prompt.
1370
1371 Global environment variables are those you use
1372 setenv/printenv to work with. To run a command stored
1373 in such a variable, you need to use the run command,
1374 and you must not use the '$' sign to access them.
1375
1376 To store commands and special characters in a
1377 variable, please use double quotation marks
1378 surrounding the whole text of the variable, instead
1379 of the backslashes before semicolons and special
1380 symbols.
1381
1382 - Default Environment:
1383 CONFIG_EXTRA_ENV_SETTINGS
1384
1385 Define this to contain any number of null terminated
1386 strings (variable = value pairs) that will be part of
1387 the default environment compiled into the boot image.
1388
1389 For example, place something like this in your
1390 board's config file:
1391
1392 #define CONFIG_EXTRA_ENV_SETTINGS \
1393 "myvar1=value1\0" \
1394 "myvar2=value2\0"
1395
1396 Warning: This method is based on knowledge about the
1397 internal format how the environment is stored by the
1398 U-Boot code. This is NOT an official, exported
1399 interface! Although it is unlikely that this format
1400 will change soon, there is no guarantee either.
1401 You better know what you are doing here.
1402
1403 Note: overly (ab)use of the default environment is
1404 discouraged. Make sure to check other ways to preset
1405 the environment like the autoscript function or the
1406 boot command first.
1407
1408 - DataFlash Support:
1409 CONFIG_HAS_DATAFLASH
1410
1411 Defining this option enables DataFlash features and
1412 allows to read/write in Dataflash via the standard
1413 commands cp, md...
1414
1415 - SystemACE Support:
1416 CONFIG_SYSTEMACE
1417
1418 Adding this option adds support for Xilinx SystemACE
1419 chips attached via some sort of local bus. The address
1420 of the chip must alsh be defined in the
1421 CFG_SYSTEMACE_BASE macro. For example:
1422
1423 #define CONFIG_SYSTEMACE
1424 #define CFG_SYSTEMACE_BASE 0xf0000000
1425
1426 When SystemACE support is added, the "ace" device type
1427 becomes available to the fat commands, i.e. fatls.
1428
1429 - Show boot progress:
1430 CONFIG_SHOW_BOOT_PROGRESS
1431
1432 Defining this option allows to add some board-
1433 specific code (calling a user-provided function
1434 "show_boot_progress(int)") that enables you to show
1435 the system's boot progress on some display (for
1436 example, some LED's) on your board. At the moment,
1437 the following checkpoints are implemented:
1438
1439 Arg Where When
1440 1 common/cmd_bootm.c before attempting to boot an image
1441 -1 common/cmd_bootm.c Image header has bad magic number
1442 2 common/cmd_bootm.c Image header has correct magic number
1443 -2 common/cmd_bootm.c Image header has bad checksum
1444 3 common/cmd_bootm.c Image header has correct checksum
1445 -3 common/cmd_bootm.c Image data has bad checksum
1446 4 common/cmd_bootm.c Image data has correct checksum
1447 -4 common/cmd_bootm.c Image is for unsupported architecture
1448 5 common/cmd_bootm.c Architecture check OK
1449 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1450 6 common/cmd_bootm.c Image Type check OK
1451 -6 common/cmd_bootm.c gunzip uncompression error
1452 -7 common/cmd_bootm.c Unimplemented compression type
1453 7 common/cmd_bootm.c Uncompression OK
1454 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1455 8 common/cmd_bootm.c Image Type check OK
1456 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1457 9 common/cmd_bootm.c Start initial ramdisk verification
1458 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1459 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1460 10 common/cmd_bootm.c Ramdisk header is OK
1461 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1462 11 common/cmd_bootm.c Ramdisk data has correct checksum
1463 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1464 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1465 13 common/cmd_bootm.c Start multifile image verification
1466 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1467 15 common/cmd_bootm.c All preparation done, transferring control to OS
1468
1469 -30 lib_ppc/board.c Fatal error, hang the system
1470 -31 post/post.c POST test failed, detected by post_output_backlog()
1471 -32 post/post.c POST test failed, detected by post_run_single()
1472
1473 -1 common/cmd_doc.c Bad usage of "doc" command
1474 -1 common/cmd_doc.c No boot device
1475 -1 common/cmd_doc.c Unknown Chip ID on boot device
1476 -1 common/cmd_doc.c Read Error on boot device
1477 -1 common/cmd_doc.c Image header has bad magic number
1478
1479 -1 common/cmd_ide.c Bad usage of "ide" command
1480 -1 common/cmd_ide.c No boot device
1481 -1 common/cmd_ide.c Unknown boot device
1482 -1 common/cmd_ide.c Unknown partition table
1483 -1 common/cmd_ide.c Invalid partition type
1484 -1 common/cmd_ide.c Read Error on boot device
1485 -1 common/cmd_ide.c Image header has bad magic number
1486
1487 -1 common/cmd_nand.c Bad usage of "nand" command
1488 -1 common/cmd_nand.c No boot device
1489 -1 common/cmd_nand.c Unknown Chip ID on boot device
1490 -1 common/cmd_nand.c Read Error on boot device
1491 -1 common/cmd_nand.c Image header has bad magic number
1492
1493 -1 common/env_common.c Environment has a bad CRC, using default
1494
1495
1496 Modem Support:
1497 --------------
1498
1499 [so far only for SMDK2400 and TRAB boards]
1500
1501 - Modem support endable:
1502 CONFIG_MODEM_SUPPORT
1503
1504 - RTS/CTS Flow control enable:
1505 CONFIG_HWFLOW
1506
1507 - Modem debug support:
1508 CONFIG_MODEM_SUPPORT_DEBUG
1509
1510 Enables debugging stuff (char screen[1024], dbg())
1511 for modem support. Useful only with BDI2000.
1512
1513 - Interrupt support (PPC):
1514
1515 There are common interrupt_init() and timer_interrupt()
1516 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1517 for cpu specific initialization. interrupt_init_cpu()
1518 should set decrementer_count to appropriate value. If
1519 cpu resets decrementer automatically after interrupt
1520 (ppc4xx) it should set decrementer_count to zero.
1521 timer_interrupt() calls timer_interrupt_cpu() for cpu
1522 specific handling. If board has watchdog / status_led
1523 / other_activity_monitor it works automatically from
1524 general timer_interrupt().
1525
1526 - General:
1527
1528 In the target system modem support is enabled when a
1529 specific key (key combination) is pressed during
1530 power-on. Otherwise U-Boot will boot normally
1531 (autoboot). The key_pressed() fuction is called from
1532 board_init(). Currently key_pressed() is a dummy
1533 function, returning 1 and thus enabling modem
1534 initialization.
1535
1536 If there are no modem init strings in the
1537 environment, U-Boot proceed to autoboot; the
1538 previous output (banner, info printfs) will be
1539 supressed, though.
1540
1541 See also: doc/README.Modem
1542
1543
1544 Configuration Settings:
1545 -----------------------
1546
1547 - CFG_LONGHELP: Defined when you want long help messages included;
1548 undefine this when you're short of memory.
1549
1550 - CFG_PROMPT: This is what U-Boot prints on the console to
1551 prompt for user input.
1552
1553 - CFG_CBSIZE: Buffer size for input from the Console
1554
1555 - CFG_PBSIZE: Buffer size for Console output
1556
1557 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1558
1559 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1560 the application (usually a Linux kernel) when it is
1561 booted
1562
1563 - CFG_BAUDRATE_TABLE:
1564 List of legal baudrate settings for this board.
1565
1566 - CFG_CONSOLE_INFO_QUIET
1567 Suppress display of console information at boot.
1568
1569 - CFG_CONSOLE_IS_IN_ENV
1570 If the board specific function
1571 extern int overwrite_console (void);
1572 returns 1, the stdin, stderr and stdout are switched to the
1573 serial port, else the settings in the environment are used.
1574
1575 - CFG_CONSOLE_OVERWRITE_ROUTINE
1576 Enable the call to overwrite_console().
1577
1578 - CFG_CONSOLE_ENV_OVERWRITE
1579 Enable overwrite of previous console environment settings.
1580
1581 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1582 Begin and End addresses of the area used by the
1583 simple memory test.
1584
1585 - CFG_ALT_MEMTEST:
1586 Enable an alternate, more extensive memory test.
1587
1588 - CFG_MEMTEST_SCRATCH:
1589 Scratch address used by the alternate memory test
1590 You only need to set this if address zero isn't writeable
1591
1592 - CFG_TFTP_LOADADDR:
1593 Default load address for network file downloads
1594
1595 - CFG_LOADS_BAUD_CHANGE:
1596 Enable temporary baudrate change while serial download
1597
1598 - CFG_SDRAM_BASE:
1599 Physical start address of SDRAM. _Must_ be 0 here.
1600
1601 - CFG_MBIO_BASE:
1602 Physical start address of Motherboard I/O (if using a
1603 Cogent motherboard)
1604
1605 - CFG_FLASH_BASE:
1606 Physical start address of Flash memory.
1607
1608 - CFG_MONITOR_BASE:
1609 Physical start address of boot monitor code (set by
1610 make config files to be same as the text base address
1611 (TEXT_BASE) used when linking) - same as
1612 CFG_FLASH_BASE when booting from flash.
1613
1614 - CFG_MONITOR_LEN:
1615 Size of memory reserved for monitor code, used to
1616 determine _at_compile_time_ (!) if the environment is
1617 embedded within the U-Boot image, or in a separate
1618 flash sector.
1619
1620 - CFG_MALLOC_LEN:
1621 Size of DRAM reserved for malloc() use.
1622
1623 - CFG_BOOTMAPSZ:
1624 Maximum size of memory mapped by the startup code of
1625 the Linux kernel; all data that must be processed by
1626 the Linux kernel (bd_info, boot arguments, eventually
1627 initrd image) must be put below this limit.
1628
1629 - CFG_MAX_FLASH_BANKS:
1630 Max number of Flash memory banks
1631
1632 - CFG_MAX_FLASH_SECT:
1633 Max number of sectors on a Flash chip
1634
1635 - CFG_FLASH_ERASE_TOUT:
1636 Timeout for Flash erase operations (in ms)
1637
1638 - CFG_FLASH_WRITE_TOUT:
1639 Timeout for Flash write operations (in ms)
1640
1641 - CFG_FLASH_LOCK_TOUT
1642 Timeout for Flash set sector lock bit operation (in ms)
1643
1644 - CFG_FLASH_UNLOCK_TOUT
1645 Timeout for Flash clear lock bits operation (in ms)
1646
1647 - CFG_FLASH_PROTECTION
1648 If defined, hardware flash sectors protection is used
1649 instead of U-Boot software protection.
1650
1651 - CFG_DIRECT_FLASH_TFTP:
1652
1653 Enable TFTP transfers directly to flash memory;
1654 without this option such a download has to be
1655 performed in two steps: (1) download to RAM, and (2)
1656 copy from RAM to flash.
1657
1658 The two-step approach is usually more reliable, since
1659 you can check if the download worked before you erase
1660 the flash, but in some situations (when sytem RAM is
1661 too limited to allow for a tempory copy of the
1662 downloaded image) this option may be very useful.
1663
1664 - CFG_FLASH_CFI:
1665 Define if the flash driver uses extra elements in the
1666 common flash structure for storing flash geometry.
1667
1668 - CFG_FLASH_CFI_DRIVER
1669 This option also enables the building of the cfi_flash driver
1670 in the drivers directory
1671
1672 - CFG_RX_ETH_BUFFER:
1673 Defines the number of ethernet receive buffers. On some
1674 ethernet controllers it is recommended to set this value
1675 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1676 buffers can be full shortly after enabling the interface
1677 on high ethernet traffic.
1678 Defaults to 4 if not defined.
1679
1680 The following definitions that deal with the placement and management
1681 of environment data (variable area); in general, we support the
1682 following configurations:
1683
1684 - CFG_ENV_IS_IN_FLASH:
1685
1686 Define this if the environment is in flash memory.
1687
1688 a) The environment occupies one whole flash sector, which is
1689 "embedded" in the text segment with the U-Boot code. This
1690 happens usually with "bottom boot sector" or "top boot
1691 sector" type flash chips, which have several smaller
1692 sectors at the start or the end. For instance, such a
1693 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1694 such a case you would place the environment in one of the
1695 4 kB sectors - with U-Boot code before and after it. With
1696 "top boot sector" type flash chips, you would put the
1697 environment in one of the last sectors, leaving a gap
1698 between U-Boot and the environment.
1699
1700 - CFG_ENV_OFFSET:
1701
1702 Offset of environment data (variable area) to the
1703 beginning of flash memory; for instance, with bottom boot
1704 type flash chips the second sector can be used: the offset
1705 for this sector is given here.
1706
1707 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1708
1709 - CFG_ENV_ADDR:
1710
1711 This is just another way to specify the start address of
1712 the flash sector containing the environment (instead of
1713 CFG_ENV_OFFSET).
1714
1715 - CFG_ENV_SECT_SIZE:
1716
1717 Size of the sector containing the environment.
1718
1719
1720 b) Sometimes flash chips have few, equal sized, BIG sectors.
1721 In such a case you don't want to spend a whole sector for
1722 the environment.
1723
1724 - CFG_ENV_SIZE:
1725
1726 If you use this in combination with CFG_ENV_IS_IN_FLASH
1727 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1728 of this flash sector for the environment. This saves
1729 memory for the RAM copy of the environment.
1730
1731 It may also save flash memory if you decide to use this
1732 when your environment is "embedded" within U-Boot code,
1733 since then the remainder of the flash sector could be used
1734 for U-Boot code. It should be pointed out that this is
1735 STRONGLY DISCOURAGED from a robustness point of view:
1736 updating the environment in flash makes it always
1737 necessary to erase the WHOLE sector. If something goes
1738 wrong before the contents has been restored from a copy in
1739 RAM, your target system will be dead.
1740
1741 - CFG_ENV_ADDR_REDUND
1742 CFG_ENV_SIZE_REDUND
1743
1744 These settings describe a second storage area used to hold
1745 a redundand copy of the environment data, so that there is
1746 a valid backup copy in case there is a power failure during
1747 a "saveenv" operation.
1748
1749 BE CAREFUL! Any changes to the flash layout, and some changes to the
1750 source code will make it necessary to adapt <board>/u-boot.lds*
1751 accordingly!
1752
1753
1754 - CFG_ENV_IS_IN_NVRAM:
1755
1756 Define this if you have some non-volatile memory device
1757 (NVRAM, battery buffered SRAM) which you want to use for the
1758 environment.
1759
1760 - CFG_ENV_ADDR:
1761 - CFG_ENV_SIZE:
1762
1763 These two #defines are used to determin the memory area you
1764 want to use for environment. It is assumed that this memory
1765 can just be read and written to, without any special
1766 provision.
1767
1768 BE CAREFUL! The first access to the environment happens quite early
1769 in U-Boot initalization (when we try to get the setting of for the
1770 console baudrate). You *MUST* have mappend your NVRAM area then, or
1771 U-Boot will hang.
1772
1773 Please note that even with NVRAM we still use a copy of the
1774 environment in RAM: we could work on NVRAM directly, but we want to
1775 keep settings there always unmodified except somebody uses "saveenv"
1776 to save the current settings.
1777
1778
1779 - CFG_ENV_IS_IN_EEPROM:
1780
1781 Use this if you have an EEPROM or similar serial access
1782 device and a driver for it.
1783
1784 - CFG_ENV_OFFSET:
1785 - CFG_ENV_SIZE:
1786
1787 These two #defines specify the offset and size of the
1788 environment area within the total memory of your EEPROM.
1789
1790 - CFG_I2C_EEPROM_ADDR:
1791 If defined, specified the chip address of the EEPROM device.
1792 The default address is zero.
1793
1794 - CFG_EEPROM_PAGE_WRITE_BITS:
1795 If defined, the number of bits used to address bytes in a
1796 single page in the EEPROM device. A 64 byte page, for example
1797 would require six bits.
1798
1799 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1800 If defined, the number of milliseconds to delay between
1801 page writes. The default is zero milliseconds.
1802
1803 - CFG_I2C_EEPROM_ADDR_LEN:
1804 The length in bytes of the EEPROM memory array address. Note
1805 that this is NOT the chip address length!
1806
1807 - CFG_EEPROM_SIZE:
1808 The size in bytes of the EEPROM device.
1809
1810
1811 - CFG_ENV_IS_IN_DATAFLASH:
1812
1813 Define this if you have a DataFlash memory device which you
1814 want to use for the environment.
1815
1816 - CFG_ENV_OFFSET:
1817 - CFG_ENV_ADDR:
1818 - CFG_ENV_SIZE:
1819
1820 These three #defines specify the offset and size of the
1821 environment area within the total memory of your DataFlash placed
1822 at the specified address.
1823
1824
1825 - CFG_SPI_INIT_OFFSET
1826
1827 Defines offset to the initial SPI buffer area in DPRAM. The
1828 area is used at an early stage (ROM part) if the environment
1829 is configured to reside in the SPI EEPROM: We need a 520 byte
1830 scratch DPRAM area. It is used between the two initialization
1831 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1832 to be a good choice since it makes it far enough from the
1833 start of the data area as well as from the stack pointer.
1834
1835 Please note that the environment is read-only as long as the monitor
1836 has been relocated to RAM and a RAM copy of the environment has been
1837 created; also, when using EEPROM you will have to use getenv_r()
1838 until then to read environment variables.
1839
1840 The environment is protected by a CRC32 checksum. Before the monitor
1841 is relocated into RAM, as a result of a bad CRC you will be working
1842 with the compiled-in default environment - *silently*!!! [This is
1843 necessary, because the first environment variable we need is the
1844 "baudrate" setting for the console - if we have a bad CRC, we don't
1845 have any device yet where we could complain.]
1846
1847 Note: once the monitor has been relocated, then it will complain if
1848 the default environment is used; a new CRC is computed as soon as you
1849 use the "saveenv" command to store a valid environment.
1850
1851 - CFG_FAULT_ECHO_LINK_DOWN:
1852 Echo the inverted Ethernet link state to the fault LED.
1853
1854 Note: If this option is active, then CFG_FAULT_MII_ADDR
1855 also needs to be defined.
1856
1857 - CFG_FAULT_MII_ADDR:
1858 MII address of the PHY to check for the Ethernet link state.
1859
1860 Low Level (hardware related) configuration options:
1861 ---------------------------------------------------
1862
1863 - CFG_CACHELINE_SIZE:
1864 Cache Line Size of the CPU.
1865
1866 - CFG_DEFAULT_IMMR:
1867 Default address of the IMMR after system reset.
1868
1869 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1870 and RPXsuper) to be able to adjust the position of
1871 the IMMR register after a reset.
1872
1873 - Floppy Disk Support:
1874 CFG_FDC_DRIVE_NUMBER
1875
1876 the default drive number (default value 0)
1877
1878 CFG_ISA_IO_STRIDE
1879
1880 defines the spacing between fdc chipset registers
1881 (default value 1)
1882
1883 CFG_ISA_IO_OFFSET
1884
1885 defines the offset of register from address. It
1886 depends on which part of the data bus is connected to
1887 the fdc chipset. (default value 0)
1888
1889 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1890 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1891 default value.
1892
1893 if CFG_FDC_HW_INIT is defined, then the function
1894 fdc_hw_init() is called at the beginning of the FDC
1895 setup. fdc_hw_init() must be provided by the board
1896 source code. It is used to make hardware dependant
1897 initializations.
1898
1899 - CFG_IMMR: Physical address of the Internal Memory Mapped
1900 Register; DO NOT CHANGE! (11-4)
1901 [MPC8xx systems only]
1902
1903 - CFG_INIT_RAM_ADDR:
1904
1905 Start address of memory area that can be used for
1906 initial data and stack; please note that this must be
1907 writable memory that is working WITHOUT special
1908 initialization, i. e. you CANNOT use normal RAM which
1909 will become available only after programming the
1910 memory controller and running certain initialization
1911 sequences.
1912
1913 U-Boot uses the following memory types:
1914 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1915 - MPC824X: data cache
1916 - PPC4xx: data cache
1917
1918 - CFG_GBL_DATA_OFFSET:
1919
1920 Offset of the initial data structure in the memory
1921 area defined by CFG_INIT_RAM_ADDR. Usually
1922 CFG_GBL_DATA_OFFSET is chosen such that the initial
1923 data is located at the end of the available space
1924 (sometimes written as (CFG_INIT_RAM_END -
1925 CFG_INIT_DATA_SIZE), and the initial stack is just
1926 below that area (growing from (CFG_INIT_RAM_ADDR +
1927 CFG_GBL_DATA_OFFSET) downward.
1928
1929 Note:
1930 On the MPC824X (or other systems that use the data
1931 cache for initial memory) the address chosen for
1932 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1933 point to an otherwise UNUSED address space between
1934 the top of RAM and the start of the PCI space.
1935
1936 - CFG_SIUMCR: SIU Module Configuration (11-6)
1937
1938 - CFG_SYPCR: System Protection Control (11-9)
1939
1940 - CFG_TBSCR: Time Base Status and Control (11-26)
1941
1942 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1943
1944 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1945
1946 - CFG_SCCR: System Clock and reset Control Register (15-27)
1947
1948 - CFG_OR_TIMING_SDRAM:
1949 SDRAM timing
1950
1951 - CFG_MAMR_PTA:
1952 periodic timer for refresh
1953
1954 - CFG_DER: Debug Event Register (37-47)
1955
1956 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1957 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1958 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1959 CFG_BR1_PRELIM:
1960 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1961
1962 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1963 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1964 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1965 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1966
1967 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1968 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1969 Machine Mode Register and Memory Periodic Timer
1970 Prescaler definitions (SDRAM timing)
1971
1972 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1973 enable I2C microcode relocation patch (MPC8xx);
1974 define relocation offset in DPRAM [DSP2]
1975
1976 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1977 enable SPI microcode relocation patch (MPC8xx);
1978 define relocation offset in DPRAM [SCC4]
1979
1980 - CFG_USE_OSCCLK:
1981 Use OSCM clock mode on MBX8xx board. Be careful,
1982 wrong setting might damage your board. Read
1983 doc/README.MBX before setting this variable!
1984
1985 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1986 Offset of the bootmode word in DPRAM used by post
1987 (Power On Self Tests). This definition overrides
1988 #define'd default value in commproc.h resp.
1989 cpm_8260.h.
1990
1991 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1992 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1993 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1994 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1995 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1996 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1997 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1998 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1999 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2000
2001 Building the Software:
2002 ======================
2003
2004 Building U-Boot has been tested in native PPC environments (on a
2005 PowerBook G3 running LinuxPPC 2000) and in cross environments
2006 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2007 NetBSD 1.5 on x86).
2008
2009 If you are not using a native PPC environment, it is assumed that you
2010 have the GNU cross compiling tools available in your path and named
2011 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2012 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2013 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2014 change it to:
2015
2016 CROSS_COMPILE = ppc_4xx-
2017
2018
2019 U-Boot is intended to be simple to build. After installing the
2020 sources you must configure U-Boot for one specific board type. This
2021 is done by typing:
2022
2023 make NAME_config
2024
2025 where "NAME_config" is the name of one of the existing
2026 configurations; the following names are supported:
2027
2028 ADCIOP_config GTH_config TQM850L_config
2029 ADS860_config IP860_config TQM855L_config
2030 AR405_config IVML24_config TQM860L_config
2031 CANBT_config IVMS8_config WALNUT405_config
2032 CPCI405_config LANTEC_config cogent_common_config
2033 CPCIISER4_config MBX_config cogent_mpc8260_config
2034 CU824_config MBX860T_config cogent_mpc8xx_config
2035 ESTEEM192E_config RPXlite_config hermes_config
2036 ETX094_config RPXsuper_config hymod_config
2037 FADS823_config SM850_config lwmon_config
2038 FADS850SAR_config SPD823TS_config pcu_e_config
2039 FADS860T_config SXNI855T_config rsdproto_config
2040 FPS850L_config Sandpoint8240_config sbc8260_config
2041 GENIETV_config TQM823L_config PIP405_config
2042 GEN860T_config EBONY_config FPS860L_config
2043 ELPT860_config cmi_mpc5xx_config NETVIA_config
2044 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
2045 omap1610inn_config ZPC1900_config MPC8540ADS_config
2046 MPC8560ADS_config QS850_config QS823_config
2047 QS860T_config DUET_ADS_config omap1610h2_config
2048
2049 Note: for some board special configuration names may exist; check if
2050 additional information is available from the board vendor; for
2051 instance, the TQM8xxL systems run normally at 50 MHz and use a
2052 SCC for 10baseT ethernet; there are also systems with 80 MHz
2053 CPU clock, and an optional Fast Ethernet module is available
2054 for CPU's with FEC. You can select such additional "features"
2055 when chosing the configuration, i. e.
2056
2057 make TQM860L_config
2058 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
2059
2060 make TQM860L_FEC_config
2061 - will configure for a TQM860L at 50MHz with FEC for ethernet
2062
2063 make TQM860L_80MHz_config
2064 - will configure for a TQM860L at 80 MHz, with normal 10baseT
2065 interface
2066
2067 make TQM860L_FEC_80MHz_config
2068 - will configure for a TQM860L at 80 MHz with FEC for ethernet
2069
2070 make TQM823L_LCD_config
2071 - will configure for a TQM823L with U-Boot console on LCD
2072
2073 make TQM823L_LCD_80MHz_config
2074 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
2075
2076 etc.
2077
2078
2079 Finally, type "make all", and you should get some working U-Boot
2080 images ready for download to / installation on your system:
2081
2082 - "u-boot.bin" is a raw binary image
2083 - "u-boot" is an image in ELF binary format
2084 - "u-boot.srec" is in Motorola S-Record format
2085
2086
2087 Please be aware that the Makefiles assume you are using GNU make, so
2088 for instance on NetBSD you might need to use "gmake" instead of
2089 native "make".
2090
2091
2092 If the system board that you have is not listed, then you will need
2093 to port U-Boot to your hardware platform. To do this, follow these
2094 steps:
2095
2096 1. Add a new configuration option for your board to the toplevel
2097 "Makefile" and to the "MAKEALL" script, using the existing
2098 entries as examples. Note that here and at many other places
2099 boards and other names are listed in alphabetical sort order. Please
2100 keep this order.
2101 2. Create a new directory to hold your board specific code. Add any
2102 files you need. In your board directory, you will need at least
2103 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2104 3. Create a new configuration file "include/configs/<board>.h" for
2105 your board
2106 3. If you're porting U-Boot to a new CPU, then also create a new
2107 directory to hold your CPU specific code. Add any files you need.
2108 4. Run "make <board>_config" with your new name.
2109 5. Type "make", and you should get a working "u-boot.srec" file
2110 to be installed on your target system.
2111 6. Debug and solve any problems that might arise.
2112 [Of course, this last step is much harder than it sounds.]
2113
2114
2115 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2116 ==============================================================
2117
2118 If you have modified U-Boot sources (for instance added a new board
2119 or support for new devices, a new CPU, etc.) you are expected to
2120 provide feedback to the other developers. The feedback normally takes
2121 the form of a "patch", i. e. a context diff against a certain (latest
2122 official or latest in CVS) version of U-Boot sources.
2123
2124 But before you submit such a patch, please verify that your modifi-
2125 cation did not break existing code. At least make sure that *ALL* of
2126 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2127 just run the "MAKEALL" script, which will configure and build U-Boot
2128 for ALL supported system. Be warned, this will take a while. You can
2129 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2130 environment variable to the script, i. e. to use the cross tools from
2131 MontaVista's Hard Hat Linux you can type
2132
2133 CROSS_COMPILE=ppc_8xx- MAKEALL
2134
2135 or to build on a native PowerPC system you can type
2136
2137 CROSS_COMPILE=' ' MAKEALL
2138
2139 See also "U-Boot Porting Guide" below.
2140
2141
2142 Monitor Commands - Overview:
2143 ============================
2144
2145 go - start application at address 'addr'
2146 run - run commands in an environment variable
2147 bootm - boot application image from memory
2148 bootp - boot image via network using BootP/TFTP protocol
2149 tftpboot- boot image via network using TFTP protocol
2150 and env variables "ipaddr" and "serverip"
2151 (and eventually "gatewayip")
2152 rarpboot- boot image via network using RARP/TFTP protocol
2153 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2154 loads - load S-Record file over serial line
2155 loadb - load binary file over serial line (kermit mode)
2156 md - memory display
2157 mm - memory modify (auto-incrementing)
2158 nm - memory modify (constant address)
2159 mw - memory write (fill)
2160 cp - memory copy
2161 cmp - memory compare
2162 crc32 - checksum calculation
2163 imd - i2c memory display
2164 imm - i2c memory modify (auto-incrementing)
2165 inm - i2c memory modify (constant address)
2166 imw - i2c memory write (fill)
2167 icrc32 - i2c checksum calculation
2168 iprobe - probe to discover valid I2C chip addresses
2169 iloop - infinite loop on address range
2170 isdram - print SDRAM configuration information
2171 sspi - SPI utility commands
2172 base - print or set address offset
2173 printenv- print environment variables
2174 setenv - set environment variables
2175 saveenv - save environment variables to persistent storage
2176 protect - enable or disable FLASH write protection
2177 erase - erase FLASH memory
2178 flinfo - print FLASH memory information
2179 bdinfo - print Board Info structure
2180 iminfo - print header information for application image
2181 coninfo - print console devices and informations
2182 ide - IDE sub-system
2183 loop - infinite loop on address range
2184 mtest - simple RAM test
2185 icache - enable or disable instruction cache
2186 dcache - enable or disable data cache
2187 reset - Perform RESET of the CPU
2188 echo - echo args to console
2189 version - print monitor version
2190 help - print online help
2191 ? - alias for 'help'
2192
2193
2194 Monitor Commands - Detailed Description:
2195 ========================================
2196
2197 TODO.
2198
2199 For now: just type "help <command>".
2200
2201
2202 Environment Variables:
2203 ======================
2204
2205 U-Boot supports user configuration using Environment Variables which
2206 can be made persistent by saving to Flash memory.
2207
2208 Environment Variables are set using "setenv", printed using
2209 "printenv", and saved to Flash using "saveenv". Using "setenv"
2210 without a value can be used to delete a variable from the
2211 environment. As long as you don't save the environment you are
2212 working with an in-memory copy. In case the Flash area containing the
2213 environment is erased by accident, a default environment is provided.
2214
2215 Some configuration options can be set using Environment Variables:
2216
2217 baudrate - see CONFIG_BAUDRATE
2218
2219 bootdelay - see CONFIG_BOOTDELAY
2220
2221 bootcmd - see CONFIG_BOOTCOMMAND
2222
2223 bootargs - Boot arguments when booting an RTOS image
2224
2225 bootfile - Name of the image to load with TFTP
2226
2227 autoload - if set to "no" (any string beginning with 'n'),
2228 "bootp" will just load perform a lookup of the
2229 configuration from the BOOTP server, but not try to
2230 load any image using TFTP
2231
2232 autostart - if set to "yes", an image loaded using the "bootp",
2233 "rarpboot", "tftpboot" or "diskboot" commands will
2234 be automatically started (by internally calling
2235 "bootm")
2236
2237 If set to "no", a standalone image passed to the
2238 "bootm" command will be copied to the load address
2239 (and eventually uncompressed), but NOT be started.
2240 This can be used to load and uncompress arbitrary
2241 data.
2242
2243 initrd_high - restrict positioning of initrd images:
2244 If this variable is not set, initrd images will be
2245 copied to the highest possible address in RAM; this
2246 is usually what you want since it allows for
2247 maximum initrd size. If for some reason you want to
2248 make sure that the initrd image is loaded below the
2249 CFG_BOOTMAPSZ limit, you can set this environment
2250 variable to a value of "no" or "off" or "0".
2251 Alternatively, you can set it to a maximum upper
2252 address to use (U-Boot will still check that it
2253 does not overwrite the U-Boot stack and data).
2254
2255 For instance, when you have a system with 16 MB
2256 RAM, and want to reserve 4 MB from use by Linux,
2257 you can do this by adding "mem=12M" to the value of
2258 the "bootargs" variable. However, now you must make
2259 sure that the initrd image is placed in the first
2260 12 MB as well - this can be done with
2261
2262 setenv initrd_high 00c00000
2263
2264 If you set initrd_high to 0xFFFFFFFF, this is an
2265 indication to U-Boot that all addresses are legal
2266 for the Linux kernel, including addresses in flash
2267 memory. In this case U-Boot will NOT COPY the
2268 ramdisk at all. This may be useful to reduce the
2269 boot time on your system, but requires that this
2270 feature is supported by your Linux kernel.
2271
2272 ipaddr - IP address; needed for tftpboot command
2273
2274 loadaddr - Default load address for commands like "bootp",
2275 "rarpboot", "tftpboot", "loadb" or "diskboot"
2276
2277 loads_echo - see CONFIG_LOADS_ECHO
2278
2279 serverip - TFTP server IP address; needed for tftpboot command
2280
2281 bootretry - see CONFIG_BOOT_RETRY_TIME
2282
2283 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2284
2285 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2286
2287
2288 The following environment variables may be used and automatically
2289 updated by the network boot commands ("bootp" and "rarpboot"),
2290 depending the information provided by your boot server:
2291
2292 bootfile - see above
2293 dnsip - IP address of your Domain Name Server
2294 dnsip2 - IP address of your secondary Domain Name Server
2295 gatewayip - IP address of the Gateway (Router) to use
2296 hostname - Target hostname
2297 ipaddr - see above
2298 netmask - Subnet Mask
2299 rootpath - Pathname of the root filesystem on the NFS server
2300 serverip - see above
2301
2302
2303 There are two special Environment Variables:
2304
2305 serial# - contains hardware identification information such
2306 as type string and/or serial number
2307 ethaddr - Ethernet address
2308
2309 These variables can be set only once (usually during manufacturing of
2310 the board). U-Boot refuses to delete or overwrite these variables
2311 once they have been set once.
2312
2313
2314 Further special Environment Variables:
2315
2316 ver - Contains the U-Boot version string as printed
2317 with the "version" command. This variable is
2318 readonly (see CONFIG_VERSION_VARIABLE).
2319
2320
2321 Please note that changes to some configuration parameters may take
2322 only effect after the next boot (yes, that's just like Windoze :-).
2323
2324
2325 Command Line Parsing:
2326 =====================
2327
2328 There are two different command line parsers available with U-Boot:
2329 the old "simple" one, and the much more powerful "hush" shell:
2330
2331 Old, simple command line parser:
2332 --------------------------------
2333
2334 - supports environment variables (through setenv / saveenv commands)
2335 - several commands on one line, separated by ';'
2336 - variable substitution using "... $(name) ..." syntax
2337 - special characters ('$', ';') can be escaped by prefixing with '\',
2338 for example:
2339 setenv bootcmd bootm \$(address)
2340 - You can also escape text by enclosing in single apostrophes, for example:
2341 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2342
2343 Hush shell:
2344 -----------
2345
2346 - similar to Bourne shell, with control structures like
2347 if...then...else...fi, for...do...done; while...do...done,
2348 until...do...done, ...
2349 - supports environment ("global") variables (through setenv / saveenv
2350 commands) and local shell variables (through standard shell syntax
2351 "name=value"); only environment variables can be used with "run"
2352 command
2353
2354 General rules:
2355 --------------
2356
2357 (1) If a command line (or an environment variable executed by a "run"
2358 command) contains several commands separated by semicolon, and
2359 one of these commands fails, then the remaining commands will be
2360 executed anyway.
2361
2362 (2) If you execute several variables with one call to run (i. e.
2363 calling run with a list af variables as arguments), any failing
2364 command will cause "run" to terminate, i. e. the remaining
2365 variables are not executed.
2366
2367 Note for Redundant Ethernet Interfaces:
2368 =======================================
2369
2370 Some boards come with redundant ethernet interfaces; U-Boot supports
2371 such configurations and is capable of automatic selection of a
2372 "working" interface when needed. MAC assignment works as follows:
2373
2374 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2375 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2376 "eth1addr" (=>eth1), "eth2addr", ...
2377
2378 If the network interface stores some valid MAC address (for instance
2379 in SROM), this is used as default address if there is NO correspon-
2380 ding setting in the environment; if the corresponding environment
2381 variable is set, this overrides the settings in the card; that means:
2382
2383 o If the SROM has a valid MAC address, and there is no address in the
2384 environment, the SROM's address is used.
2385
2386 o If there is no valid address in the SROM, and a definition in the
2387 environment exists, then the value from the environment variable is
2388 used.
2389
2390 o If both the SROM and the environment contain a MAC address, and
2391 both addresses are the same, this MAC address is used.
2392
2393 o If both the SROM and the environment contain a MAC address, and the
2394 addresses differ, the value from the environment is used and a
2395 warning is printed.
2396
2397 o If neither SROM nor the environment contain a MAC address, an error
2398 is raised.
2399
2400
2401 Image Formats:
2402 ==============
2403
2404 The "boot" commands of this monitor operate on "image" files which
2405 can be basicly anything, preceeded by a special header; see the
2406 definitions in include/image.h for details; basicly, the header
2407 defines the following image properties:
2408
2409 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2410 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2411 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2412 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2413 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2414 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2415 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC).
2416 * Compression Type (uncompressed, gzip, bzip2)
2417 * Load Address
2418 * Entry Point
2419 * Image Name
2420 * Image Timestamp
2421
2422 The header is marked by a special Magic Number, and both the header
2423 and the data portions of the image are secured against corruption by
2424 CRC32 checksums.
2425
2426
2427 Linux Support:
2428 ==============
2429
2430 Although U-Boot should support any OS or standalone application
2431 easily, the main focus has always been on Linux during the design of
2432 U-Boot.
2433
2434 U-Boot includes many features that so far have been part of some
2435 special "boot loader" code within the Linux kernel. Also, any
2436 "initrd" images to be used are no longer part of one big Linux image;
2437 instead, kernel and "initrd" are separate images. This implementation
2438 serves several purposes:
2439
2440 - the same features can be used for other OS or standalone
2441 applications (for instance: using compressed images to reduce the
2442 Flash memory footprint)
2443
2444 - it becomes much easier to port new Linux kernel versions because
2445 lots of low-level, hardware dependent stuff are done by U-Boot
2446
2447 - the same Linux kernel image can now be used with different "initrd"
2448 images; of course this also means that different kernel images can
2449 be run with the same "initrd". This makes testing easier (you don't
2450 have to build a new "zImage.initrd" Linux image when you just
2451 change a file in your "initrd"). Also, a field-upgrade of the
2452 software is easier now.
2453
2454
2455 Linux HOWTO:
2456 ============
2457
2458 Porting Linux to U-Boot based systems:
2459 ---------------------------------------
2460
2461 U-Boot cannot save you from doing all the necessary modifications to
2462 configure the Linux device drivers for use with your target hardware
2463 (no, we don't intend to provide a full virtual machine interface to
2464 Linux :-).
2465
2466 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2467
2468 Just make sure your machine specific header file (for instance
2469 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2470 Information structure as we define in include/u-boot.h, and make
2471 sure that your definition of IMAP_ADDR uses the same value as your
2472 U-Boot configuration in CFG_IMMR.
2473
2474
2475 Configuring the Linux kernel:
2476 -----------------------------
2477
2478 No specific requirements for U-Boot. Make sure you have some root
2479 device (initial ramdisk, NFS) for your target system.
2480
2481
2482 Building a Linux Image:
2483 -----------------------
2484
2485 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2486 not used. If you use recent kernel source, a new build target
2487 "uImage" will exist which automatically builds an image usable by
2488 U-Boot. Most older kernels also have support for a "pImage" target,
2489 which was introduced for our predecessor project PPCBoot and uses a
2490 100% compatible format.
2491
2492 Example:
2493
2494 make TQM850L_config
2495 make oldconfig
2496 make dep
2497 make uImage
2498
2499 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2500 encapsulate a compressed Linux kernel image with header information,
2501 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2502
2503 * build a standard "vmlinux" kernel image (in ELF binary format):
2504
2505 * convert the kernel into a raw binary image:
2506
2507 ${CROSS_COMPILE}-objcopy -O binary \
2508 -R .note -R .comment \
2509 -S vmlinux linux.bin
2510
2511 * compress the binary image:
2512
2513 gzip -9 linux.bin
2514
2515 * package compressed binary image for U-Boot:
2516
2517 mkimage -A ppc -O linux -T kernel -C gzip \
2518 -a 0 -e 0 -n "Linux Kernel Image" \
2519 -d linux.bin.gz uImage
2520
2521
2522 The "mkimage" tool can also be used to create ramdisk images for use
2523 with U-Boot, either separated from the Linux kernel image, or
2524 combined into one file. "mkimage" encapsulates the images with a 64
2525 byte header containing information about target architecture,
2526 operating system, image type, compression method, entry points, time
2527 stamp, CRC32 checksums, etc.
2528
2529 "mkimage" can be called in two ways: to verify existing images and
2530 print the header information, or to build new images.
2531
2532 In the first form (with "-l" option) mkimage lists the information
2533 contained in the header of an existing U-Boot image; this includes
2534 checksum verification:
2535
2536 tools/mkimage -l image
2537 -l ==> list image header information
2538
2539 The second form (with "-d" option) is used to build a U-Boot image
2540 from a "data file" which is used as image payload:
2541
2542 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2543 -n name -d data_file image
2544 -A ==> set architecture to 'arch'
2545 -O ==> set operating system to 'os'
2546 -T ==> set image type to 'type'
2547 -C ==> set compression type 'comp'
2548 -a ==> set load address to 'addr' (hex)
2549 -e ==> set entry point to 'ep' (hex)
2550 -n ==> set image name to 'name'
2551 -d ==> use image data from 'datafile'
2552
2553 Right now, all Linux kernels use the same load address (0x00000000),
2554 but the entry point address depends on the kernel version:
2555
2556 - 2.2.x kernels have the entry point at 0x0000000C,
2557 - 2.3.x and later kernels have the entry point at 0x00000000.
2558
2559 So a typical call to build a U-Boot image would read:
2560
2561 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2562 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2563 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2564 > examples/uImage.TQM850L
2565 Image Name: 2.4.4 kernel for TQM850L
2566 Created: Wed Jul 19 02:34:59 2000
2567 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2568 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2569 Load Address: 0x00000000
2570 Entry Point: 0x00000000
2571
2572 To verify the contents of the image (or check for corruption):
2573
2574 -> tools/mkimage -l examples/uImage.TQM850L
2575 Image Name: 2.4.4 kernel for TQM850L
2576 Created: Wed Jul 19 02:34:59 2000
2577 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2578 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2579 Load Address: 0x00000000
2580 Entry Point: 0x00000000
2581
2582 NOTE: for embedded systems where boot time is critical you can trade
2583 speed for memory and install an UNCOMPRESSED image instead: this
2584 needs more space in Flash, but boots much faster since it does not
2585 need to be uncompressed:
2586
2587 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2588 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2589 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2590 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2591 > examples/uImage.TQM850L-uncompressed
2592 Image Name: 2.4.4 kernel for TQM850L
2593 Created: Wed Jul 19 02:34:59 2000
2594 Image Type: PowerPC Linux Kernel Image (uncompressed)
2595 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2596 Load Address: 0x00000000
2597 Entry Point: 0x00000000
2598
2599
2600 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2601 when your kernel is intended to use an initial ramdisk:
2602
2603 -> tools/mkimage -n 'Simple Ramdisk Image' \
2604 > -A ppc -O linux -T ramdisk -C gzip \
2605 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2606 Image Name: Simple Ramdisk Image
2607 Created: Wed Jan 12 14:01:50 2000
2608 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2609 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2610 Load Address: 0x00000000
2611 Entry Point: 0x00000000
2612
2613
2614 Installing a Linux Image:
2615 -------------------------
2616
2617 To downloading a U-Boot image over the serial (console) interface,
2618 you must convert the image to S-Record format:
2619
2620 objcopy -I binary -O srec examples/image examples/image.srec
2621
2622 The 'objcopy' does not understand the information in the U-Boot
2623 image header, so the resulting S-Record file will be relative to
2624 address 0x00000000. To load it to a given address, you need to
2625 specify the target address as 'offset' parameter with the 'loads'
2626 command.
2627
2628 Example: install the image to address 0x40100000 (which on the
2629 TQM8xxL is in the first Flash bank):
2630
2631 => erase 40100000 401FFFFF
2632
2633 .......... done
2634 Erased 8 sectors
2635
2636 => loads 40100000
2637 ## Ready for S-Record download ...
2638 ~>examples/image.srec
2639 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2640 ...
2641 15989 15990 15991 15992
2642 [file transfer complete]
2643 [connected]
2644 ## Start Addr = 0x00000000
2645
2646
2647 You can check the success of the download using the 'iminfo' command;
2648 this includes a checksum verification so you can be sure no data
2649 corruption happened:
2650
2651 => imi 40100000
2652
2653 ## Checking Image at 40100000 ...
2654 Image Name: 2.2.13 for initrd on TQM850L
2655 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2656 Data Size: 335725 Bytes = 327 kB = 0 MB
2657 Load Address: 00000000
2658 Entry Point: 0000000c
2659 Verifying Checksum ... OK
2660
2661
2662 Boot Linux:
2663 -----------
2664
2665 The "bootm" command is used to boot an application that is stored in
2666 memory (RAM or Flash). In case of a Linux kernel image, the contents
2667 of the "bootargs" environment variable is passed to the kernel as
2668 parameters. You can check and modify this variable using the
2669 "printenv" and "setenv" commands:
2670
2671
2672 => printenv bootargs
2673 bootargs=root=/dev/ram
2674
2675 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2676
2677 => printenv bootargs
2678 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2679
2680 => bootm 40020000
2681 ## Booting Linux kernel at 40020000 ...
2682 Image Name: 2.2.13 for NFS on TQM850L
2683 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2684 Data Size: 381681 Bytes = 372 kB = 0 MB
2685 Load Address: 00000000
2686 Entry Point: 0000000c
2687 Verifying Checksum ... OK
2688 Uncompressing Kernel Image ... OK
2689 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
2690 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2691 time_init: decrementer frequency = 187500000/60
2692 Calibrating delay loop... 49.77 BogoMIPS
2693 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2694 ...
2695
2696 If you want to boot a Linux kernel with initial ram disk, you pass
2697 the memory addresses of both the kernel and the initrd image (PPBCOOT
2698 format!) to the "bootm" command:
2699
2700 => imi 40100000 40200000
2701
2702 ## Checking Image at 40100000 ...
2703 Image Name: 2.2.13 for initrd on TQM850L
2704 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2705 Data Size: 335725 Bytes = 327 kB = 0 MB
2706 Load Address: 00000000
2707 Entry Point: 0000000c
2708 Verifying Checksum ... OK
2709
2710 ## Checking Image at 40200000 ...
2711 Image Name: Simple Ramdisk Image
2712 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2713 Data Size: 566530 Bytes = 553 kB = 0 MB
2714 Load Address: 00000000
2715 Entry Point: 00000000
2716 Verifying Checksum ... OK
2717
2718 => bootm 40100000 40200000
2719 ## Booting Linux kernel at 40100000 ...
2720 Image Name: 2.2.13 for initrd on TQM850L
2721 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2722 Data Size: 335725 Bytes = 327 kB = 0 MB
2723 Load Address: 00000000
2724 Entry Point: 0000000c
2725 Verifying Checksum ... OK
2726 Uncompressing Kernel Image ... OK
2727 ## Loading RAMDisk Image at 40200000 ...
2728 Image Name: Simple Ramdisk Image
2729 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2730 Data Size: 566530 Bytes = 553 kB = 0 MB
2731 Load Address: 00000000
2732 Entry Point: 00000000
2733 Verifying Checksum ... OK
2734 Loading Ramdisk ... OK
2735 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
2736 Boot arguments: root=/dev/ram
2737 time_init: decrementer frequency = 187500000/60
2738 Calibrating delay loop... 49.77 BogoMIPS
2739 ...
2740 RAMDISK: Compressed image found at block 0
2741 VFS: Mounted root (ext2 filesystem).
2742
2743 bash#
2744
2745 More About U-Boot Image Types:
2746 ------------------------------
2747
2748 U-Boot supports the following image types:
2749
2750 "Standalone Programs" are directly runnable in the environment
2751 provided by U-Boot; it is expected that (if they behave
2752 well) you can continue to work in U-Boot after return from
2753 the Standalone Program.
2754 "OS Kernel Images" are usually images of some Embedded OS which
2755 will take over control completely. Usually these programs
2756 will install their own set of exception handlers, device
2757 drivers, set up the MMU, etc. - this means, that you cannot
2758 expect to re-enter U-Boot except by resetting the CPU.
2759 "RAMDisk Images" are more or less just data blocks, and their
2760 parameters (address, size) are passed to an OS kernel that is
2761 being started.
2762 "Multi-File Images" contain several images, typically an OS
2763 (Linux) kernel image and one or more data images like
2764 RAMDisks. This construct is useful for instance when you want
2765 to boot over the network using BOOTP etc., where the boot
2766 server provides just a single image file, but you want to get
2767 for instance an OS kernel and a RAMDisk image.
2768
2769 "Multi-File Images" start with a list of image sizes, each
2770 image size (in bytes) specified by an "uint32_t" in network
2771 byte order. This list is terminated by an "(uint32_t)0".
2772 Immediately after the terminating 0 follow the images, one by
2773 one, all aligned on "uint32_t" boundaries (size rounded up to
2774 a multiple of 4 bytes).
2775
2776 "Firmware Images" are binary images containing firmware (like
2777 U-Boot or FPGA images) which usually will be programmed to
2778 flash memory.
2779
2780 "Script files" are command sequences that will be executed by
2781 U-Boot's command interpreter; this feature is especially
2782 useful when you configure U-Boot to use a real shell (hush)
2783 as command interpreter.
2784
2785
2786 Standalone HOWTO:
2787 =================
2788
2789 One of the features of U-Boot is that you can dynamically load and
2790 run "standalone" applications, which can use some resources of
2791 U-Boot like console I/O functions or interrupt services.
2792
2793 Two simple examples are included with the sources:
2794
2795 "Hello World" Demo:
2796 -------------------
2797
2798 'examples/hello_world.c' contains a small "Hello World" Demo
2799 application; it is automatically compiled when you build U-Boot.
2800 It's configured to run at address 0x00040004, so you can play with it
2801 like that:
2802
2803 => loads
2804 ## Ready for S-Record download ...
2805 ~>examples/hello_world.srec
2806 1 2 3 4 5 6 7 8 9 10 11 ...
2807 [file transfer complete]
2808 [connected]
2809 ## Start Addr = 0x00040004
2810
2811 => go 40004 Hello World! This is a test.
2812 ## Starting application at 0x00040004 ...
2813 Hello World
2814 argc = 7
2815 argv[0] = "40004"
2816 argv[1] = "Hello"
2817 argv[2] = "World!"
2818 argv[3] = "This"
2819 argv[4] = "is"
2820 argv[5] = "a"
2821 argv[6] = "test."
2822 argv[7] = "<NULL>"
2823 Hit any key to exit ...
2824
2825 ## Application terminated, rc = 0x0
2826
2827 Another example, which demonstrates how to register a CPM interrupt
2828 handler with the U-Boot code, can be found in 'examples/timer.c'.
2829 Here, a CPM timer is set up to generate an interrupt every second.
2830 The interrupt service routine is trivial, just printing a '.'
2831 character, but this is just a demo program. The application can be
2832 controlled by the following keys:
2833
2834 ? - print current values og the CPM Timer registers
2835 b - enable interrupts and start timer
2836 e - stop timer and disable interrupts
2837 q - quit application
2838
2839 => loads
2840 ## Ready for S-Record download ...
2841 ~>examples/timer.srec
2842 1 2 3 4 5 6 7 8 9 10 11 ...
2843 [file transfer complete]
2844 [connected]
2845 ## Start Addr = 0x00040004
2846
2847 => go 40004
2848 ## Starting application at 0x00040004 ...
2849 TIMERS=0xfff00980
2850 Using timer 1
2851 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2852
2853 Hit 'b':
2854 [q, b, e, ?] Set interval 1000000 us
2855 Enabling timer
2856 Hit '?':
2857 [q, b, e, ?] ........
2858 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2859 Hit '?':
2860 [q, b, e, ?] .
2861 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2862 Hit '?':
2863 [q, b, e, ?] .
2864 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2865 Hit '?':
2866 [q, b, e, ?] .
2867 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2868 Hit 'e':
2869 [q, b, e, ?] ...Stopping timer
2870 Hit 'q':
2871 [q, b, e, ?] ## Application terminated, rc = 0x0
2872
2873
2874 Minicom warning:
2875 ================
2876
2877 Over time, many people have reported problems when trying to use the
2878 "minicom" terminal emulation program for serial download. I (wd)
2879 consider minicom to be broken, and recommend not to use it. Under
2880 Unix, I recommend to use C-Kermit for general purpose use (and
2881 especially for kermit binary protocol download ("loadb" command), and
2882 use "cu" for S-Record download ("loads" command).
2883
2884 Nevertheless, if you absolutely want to use it try adding this
2885 configuration to your "File transfer protocols" section:
2886
2887 Name Program Name U/D FullScr IO-Red. Multi
2888 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2889 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2890
2891
2892 NetBSD Notes:
2893 =============
2894
2895 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2896 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2897
2898 Building requires a cross environment; it is known to work on
2899 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2900 need gmake since the Makefiles are not compatible with BSD make).
2901 Note that the cross-powerpc package does not install include files;
2902 attempting to build U-Boot will fail because <machine/ansi.h> is
2903 missing. This file has to be installed and patched manually:
2904
2905 # cd /usr/pkg/cross/powerpc-netbsd/include
2906 # mkdir powerpc
2907 # ln -s powerpc machine
2908 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2909 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2910
2911 Native builds *don't* work due to incompatibilities between native
2912 and U-Boot include files.
2913
2914 Booting assumes that (the first part of) the image booted is a
2915 stage-2 loader which in turn loads and then invokes the kernel
2916 proper. Loader sources will eventually appear in the NetBSD source
2917 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2918 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2919 details.
2920
2921
2922 Implementation Internals:
2923 =========================
2924
2925 The following is not intended to be a complete description of every
2926 implementation detail. However, it should help to understand the
2927 inner workings of U-Boot and make it easier to port it to custom
2928 hardware.
2929
2930
2931 Initial Stack, Global Data:
2932 ---------------------------
2933
2934 The implementation of U-Boot is complicated by the fact that U-Boot
2935 starts running out of ROM (flash memory), usually without access to
2936 system RAM (because the memory controller is not initialized yet).
2937 This means that we don't have writable Data or BSS segments, and BSS
2938 is not initialized as zero. To be able to get a C environment working
2939 at all, we have to allocate at least a minimal stack. Implementation
2940 options for this are defined and restricted by the CPU used: Some CPU
2941 models provide on-chip memory (like the IMMR area on MPC8xx and
2942 MPC826x processors), on others (parts of) the data cache can be
2943 locked as (mis-) used as memory, etc.
2944
2945 Chris Hallinan posted a good summary of these issues to the
2946 u-boot-users mailing list:
2947
2948 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2949 From: "Chris Hallinan" <clh@net1plus.com>
2950 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2951 ...
2952
2953 Correct me if I'm wrong, folks, but the way I understand it
2954 is this: Using DCACHE as initial RAM for Stack, etc, does not
2955 require any physical RAM backing up the cache. The cleverness
2956 is that the cache is being used as a temporary supply of
2957 necessary storage before the SDRAM controller is setup. It's
2958 beyond the scope of this list to expain the details, but you
2959 can see how this works by studying the cache architecture and
2960 operation in the architecture and processor-specific manuals.
2961
2962 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2963 is another option for the system designer to use as an
2964 initial stack/ram area prior to SDRAM being available. Either
2965 option should work for you. Using CS 4 should be fine if your
2966 board designers haven't used it for something that would
2967 cause you grief during the initial boot! It is frequently not
2968 used.
2969
2970 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2971 with your processor/board/system design. The default value
2972 you will find in any recent u-boot distribution in
2973 Walnut405.h should work for you. I'd set it to a value larger
2974 than your SDRAM module. If you have a 64MB SDRAM module, set
2975 it above 400_0000. Just make sure your board has no resources
2976 that are supposed to respond to that address! That code in
2977 start.S has been around a while and should work as is when
2978 you get the config right.
2979
2980 -Chris Hallinan
2981 DS4.COM, Inc.
2982
2983 It is essential to remember this, since it has some impact on the C
2984 code for the initialization procedures:
2985
2986 * Initialized global data (data segment) is read-only. Do not attempt
2987 to write it.
2988
2989 * Do not use any unitialized global data (or implicitely initialized
2990 as zero data - BSS segment) at all - this is undefined, initiali-
2991 zation is performed later (when relocating to RAM).
2992
2993 * Stack space is very limited. Avoid big data buffers or things like
2994 that.
2995
2996 Having only the stack as writable memory limits means we cannot use
2997 normal global data to share information beween the code. But it
2998 turned out that the implementation of U-Boot can be greatly
2999 simplified by making a global data structure (gd_t) available to all
3000 functions. We could pass a pointer to this data as argument to _all_
3001 functions, but this would bloat the code. Instead we use a feature of
3002 the GCC compiler (Global Register Variables) to share the data: we
3003 place a pointer (gd) to the global data into a register which we
3004 reserve for this purpose.
3005
3006 When choosing a register for such a purpose we are restricted by the
3007 relevant (E)ABI specifications for the current architecture, and by
3008 GCC's implementation.
3009
3010 For PowerPC, the following registers have specific use:
3011 R1: stack pointer
3012 R2: TOC pointer
3013 R3-R4: parameter passing and return values
3014 R5-R10: parameter passing
3015 R13: small data area pointer
3016 R30: GOT pointer
3017 R31: frame pointer
3018
3019 (U-Boot also uses R14 as internal GOT pointer.)
3020
3021 ==> U-Boot will use R29 to hold a pointer to the global data
3022
3023 Note: on PPC, we could use a static initializer (since the
3024 address of the global data structure is known at compile time),
3025 but it turned out that reserving a register results in somewhat
3026 smaller code - although the code savings are not that big (on
3027 average for all boards 752 bytes for the whole U-Boot image,
3028 624 text + 127 data).
3029
3030 On ARM, the following registers are used:
3031
3032 R0: function argument word/integer result
3033 R1-R3: function argument word
3034 R9: GOT pointer
3035 R10: stack limit (used only if stack checking if enabled)
3036 R11: argument (frame) pointer
3037 R12: temporary workspace
3038 R13: stack pointer
3039 R14: link register
3040 R15: program counter
3041
3042 ==> U-Boot will use R8 to hold a pointer to the global data
3043
3044
3045 Memory Management:
3046 ------------------
3047
3048 U-Boot runs in system state and uses physical addresses, i.e. the
3049 MMU is not used either for address mapping nor for memory protection.
3050
3051 The available memory is mapped to fixed addresses using the memory
3052 controller. In this process, a contiguous block is formed for each
3053 memory type (Flash, SDRAM, SRAM), even when it consists of several
3054 physical memory banks.
3055
3056 U-Boot is installed in the first 128 kB of the first Flash bank (on
3057 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3058 booting and sizing and initializing DRAM, the code relocates itself
3059 to the upper end of DRAM. Immediately below the U-Boot code some
3060 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3061 configuration setting]. Below that, a structure with global Board
3062 Info data is placed, followed by the stack (growing downward).
3063
3064 Additionally, some exception handler code is copied to the low 8 kB
3065 of DRAM (0x00000000 ... 0x00001FFF).
3066
3067 So a typical memory configuration with 16 MB of DRAM could look like
3068 this:
3069
3070 0x0000 0000 Exception Vector code
3071 :
3072 0x0000 1FFF
3073 0x0000 2000 Free for Application Use
3074 :
3075 :
3076
3077 :
3078 :
3079 0x00FB FF20 Monitor Stack (Growing downward)
3080 0x00FB FFAC Board Info Data and permanent copy of global data
3081 0x00FC 0000 Malloc Arena
3082 :
3083 0x00FD FFFF
3084 0x00FE 0000 RAM Copy of Monitor Code
3085 ... eventually: LCD or video framebuffer
3086 ... eventually: pRAM (Protected RAM - unchanged by reset)
3087 0x00FF FFFF [End of RAM]
3088
3089
3090 System Initialization:
3091 ----------------------
3092
3093 In the reset configuration, U-Boot starts at the reset entry point
3094 (on most PowerPC systens at address 0x00000100). Because of the reset
3095 configuration for CS0# this is a mirror of the onboard Flash memory.
3096 To be able to re-map memory U-Boot then jumps to its link address.
3097 To be able to implement the initialization code in C, a (small!)
3098 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3099 which provide such a feature like MPC8xx or MPC8260), or in a locked
3100 part of the data cache. After that, U-Boot initializes the CPU core,
3101 the caches and the SIU.
3102
3103 Next, all (potentially) available memory banks are mapped using a
3104 preliminary mapping. For example, we put them on 512 MB boundaries
3105 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3106 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3107 programmed for SDRAM access. Using the temporary configuration, a
3108 simple memory test is run that determines the size of the SDRAM
3109 banks.
3110
3111 When there is more than one SDRAM bank, and the banks are of
3112 different size, the largest is mapped first. For equal size, the first
3113 bank (CS2#) is mapped first. The first mapping is always for address
3114 0x00000000, with any additional banks following immediately to create
3115 contiguous memory starting from 0.
3116
3117 Then, the monitor installs itself at the upper end of the SDRAM area
3118 and allocates memory for use by malloc() and for the global Board
3119 Info data; also, the exception vector code is copied to the low RAM
3120 pages, and the final stack is set up.
3121
3122 Only after this relocation will you have a "normal" C environment;
3123 until that you are restricted in several ways, mostly because you are
3124 running from ROM, and because the code will have to be relocated to a
3125 new address in RAM.
3126
3127
3128 U-Boot Porting Guide:
3129 ----------------------
3130
3131 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3132 list, October 2002]
3133
3134
3135 int main (int argc, char *argv[])
3136 {
3137 sighandler_t no_more_time;
3138
3139 signal (SIGALRM, no_more_time);
3140 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3141
3142 if (available_money > available_manpower) {
3143 pay consultant to port U-Boot;
3144 return 0;
3145 }
3146
3147 Download latest U-Boot source;
3148
3149 Subscribe to u-boot-users mailing list;
3150
3151 if (clueless) {
3152 email ("Hi, I am new to U-Boot, how do I get started?");
3153 }
3154
3155 while (learning) {
3156 Read the README file in the top level directory;
3157 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3158 Read the source, Luke;
3159 }
3160
3161 if (available_money > toLocalCurrency ($2500)) {
3162 Buy a BDI2000;
3163 } else {
3164 Add a lot of aggravation and time;
3165 }
3166
3167 Create your own board support subdirectory;
3168
3169 Create your own board config file;
3170
3171 while (!running) {
3172 do {
3173 Add / modify source code;
3174 } until (compiles);
3175 Debug;
3176 if (clueless)
3177 email ("Hi, I am having problems...");
3178 }
3179 Send patch file to Wolfgang;
3180
3181 return 0;
3182 }
3183
3184 void no_more_time (int sig)
3185 {
3186 hire_a_guru();
3187 }
3188
3189
3190 Coding Standards:
3191 -----------------
3192
3193 All contributions to U-Boot should conform to the Linux kernel
3194 coding style; see the file "Documentation/CodingStyle" in your Linux
3195 kernel source directory.
3196
3197 Please note that U-Boot is implemented in C (and to some small parts
3198 in Assembler); no C++ is used, so please do not use C++ style
3199 comments (//) in your code.
3200
3201 Please also stick to the following formatting rules:
3202 - remove any trailing white space
3203 - use TAB characters for indentation, not spaces
3204 - make sure NOT to use DOS '\r\n' line feeds
3205 - do not add more than 2 empty lines to source files
3206 - do not add trailing empty lines to source files
3207
3208 Submissions which do not conform to the standards may be returned
3209 with a request to reformat the changes.
3210
3211
3212 Submitting Patches:
3213 -------------------
3214
3215 Since the number of patches for U-Boot is growing, we need to
3216 establish some rules. Submissions which do not conform to these rules
3217 may be rejected, even when they contain important and valuable stuff.
3218
3219
3220 When you send a patch, please include the following information with
3221 it:
3222
3223 * For bug fixes: a description of the bug and how your patch fixes
3224 this bug. Please try to include a way of demonstrating that the
3225 patch actually fixes something.
3226
3227 * For new features: a description of the feature and your
3228 implementation.
3229
3230 * A CHANGELOG entry as plaintext (separate from the patch)
3231
3232 * For major contributions, your entry to the CREDITS file
3233
3234 * When you add support for a new board, don't forget to add this
3235 board to the MAKEALL script, too.
3236
3237 * If your patch adds new configuration options, don't forget to
3238 document these in the README file.
3239
3240 * The patch itself. If you are accessing the CVS repository use "cvs
3241 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3242 version of diff does not support these options, then get the latest
3243 version of GNU diff.
3244
3245 The current directory when running this command shall be the top
3246 level directory of the U-Boot source tree, or it's parent directory
3247 (i. e. please make sure that your patch includes sufficient
3248 directory information for the affected files).
3249
3250 We accept patches as plain text, MIME attachments or as uuencoded
3251 gzipped text.
3252
3253 * If one logical set of modifications affects or creates several
3254 files, all these changes shall be submitted in a SINGLE patch file.
3255
3256 * Changesets that contain different, unrelated modifications shall be
3257 submitted as SEPARATE patches, one patch per changeset.
3258
3259
3260 Notes:
3261
3262 * Before sending the patch, run the MAKEALL script on your patched
3263 source tree and make sure that no errors or warnings are reported
3264 for any of the boards.
3265
3266 * Keep your modifications to the necessary minimum: A patch
3267 containing several unrelated changes or arbitrary reformats will be
3268 returned with a request to re-formatting / split it.
3269
3270 * If you modify existing code, make sure that your new code does not
3271 add to the memory footprint of the code ;-) Small is beautiful!
3272 When adding new features, these should compile conditionally only
3273 (using #ifdef), and the resulting code with the new feature
3274 disabled must not need more memory than the old code without your
3275 modification.