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