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1#
2# (C) Copyright 2000 - 2002
3# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
4#
5# See file CREDITS for list of people who contributed to this
6# project.
7#
8# This program is free software; you can redistribute it and/or
9# modify it under the terms of the GNU General Public License as
10# published by the Free Software Foundation; either version 2 of
11# the License, or (at your option) any later version.
12#
13# This program is distributed in the hope that it will be useful,
14# but WITHOUT ANY WARRANTY; without even the implied warranty of
15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16# GNU General Public License for more details.
17#
18# You should have received a copy of the GNU General Public License
19# along with this program; if not, write to the Free Software
20# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21# MA 02111-1307 USA
22#
23
24Summary:
25========
26
27This directory contains the source code for U-Boot, a monitor for
28Embedded PowerPC boards, which can be installed in a boot ROM and
29used to test the hardware or download and run application code.
30
31The development of U-Boot is closely related to Linux: some parts of
32the source code originate in the Linux source tree, we still have
33some header files in common, and special provision has been made to
34support booting of Linux images.
35
36Some attention has been paid to make this software easily
37configurable and extendable. For instance, all monitor commands are
38implemented with the same call interface, so that it's very easy to
39add new commands. Also, instead of permanently adding rarely used
40code (for instance hardware test utilities) to the monitor, you can
41load and run it dynamically.
42
43
44Status:
45=======
46
47In general, all boards for which a configuration option exists in the
48Makefile have been tested to some extent and can be considered
49"working". In fact, many of them are used in production systems.
50
51In case of problems see the CHANGELOG and CREDITS files to find out
52who contributed the specific port.
53
54Exception from this rule: the port to the Sandpoint 8240 has not been
55completed yet.
56
57
58Where to get help:
59==================
60
61In case you have questions about, problems with or contributions for
62U-Boot you should send a message to the U-Boot mailing list at
63<u-boot-users@lists.sourceforge.net>. There is also an archive of
64previous traffic on the mailing list - please search the archive
65before asking FAQ's. Please see
66http://lists.sourceforge.net/lists/listinfo/u-boot-users/
67
68
69Where we come from:
70===================
71
72- start from 8xxrom sources
73- clean up code
74- make it easier to add custom boards
75- make it possible to add other [PowerPC] CPUs
76- extend functions, especially:
77 * Provide extended interface to Linux boot loader
78 * S-Record download
79 * network boot
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81- add other CPU families (starting with ARM)
82
83
84Directory Hierarchy:
85====================
86
87- board Board dependend files
88- common Misc architecture independend functions
89- cpu CPU specific files
90- disk Code for disk drive partition handling
91- doc Documentation (don't expect too much)
92- drivers Common used device drivers
93- dtt Digital Thermometer and Thermostat drivers
94- examples Example code for standalone applications, etc.
95- include Header Files
96- disk Harddisk interface code
97- net Networking code
98- ppc Files generic to PowerPC architecture
99- post Power On Self Test
100- post/arch Symlink to architecture specific Power On Self Test
101- post/arch-ppc PowerPC architecture specific Power On Self Test
102- post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
103- post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
104- rtc Real Time Clock drivers
105- tools Tools to build S-Record or U-Boot images, etc.
106
107- cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
108- cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
109- cpu/mpc824x Files specific to Motorola MPC824x CPUs
110- cpu/mpc8260 Files specific to Motorola MPC8260 CPU
111- cpu/ppc4xx Files specific to IBM 4xx CPUs
112
113- board/RPXClassic
114 Files specific to RPXClassic boards
115- board/RPXlite Files specific to RPXlite boards
116- board/c2mon Files specific to c2mon boards
117- board/cogent Files specific to Cogent boards
118 (need further configuration)
119 Files specific to CPCIISER4 boards
120- board/cpu86 Files specific to CPU86 boards
121- board/cray/ Files specific to boards manufactured by Cray
122- board/cray/L1 Files specific to L1 boards
123- board/cu824 Files specific to CU824 boards
124- board/ebony Files specific to IBM Ebony board
125- board/eric Files specific to ERIC boards
126- board/esd/ Files specific to boards manufactured by ESD
127- board/esd/adciop Files specific to ADCIOP boards
128- board/esd/ar405 Files specific to AR405 boards
129- board/esd/canbt Files specific to CANBT boards
130- board/esd/cpci405 Files specific to CPCI405 boards
131- board/esd/cpciiser4 Files specific to CPCIISER4 boards
132- board/esd/common Common files for ESD boards
133- board/esd/dasa_sim Files specific to DASA_SIM boards
134- board/esd/du405 Files specific to DU405 boards
135- board/esd/ocrtc Files specific to OCRTC boards
136- board/esd/pci405 Files specific to PCI405 boards
137- board/esteem192e
138 Files specific to ESTEEM192E boards
139- board/etx094 Files specific to ETX_094 boards
140- board/evb64260
141 Files specific to EVB64260 boards
142- board/fads Files specific to FADS boards
143- board/flagadm Files specific to FLAGADM boards
144- board/gen860t Files specific to GEN860T boards
145- board/genietv Files specific to GENIETV boards
146- board/gth Files specific to GTH boards
147- board/hermes Files specific to HERMES boards
148- board/hymod Files specific to HYMOD boards
149- board/icu862 Files specific to ICU862 boards
150- board/ip860 Files specific to IP860 boards
151- board/iphase4539
152 Files specific to Interphase4539 boards
153- board/ivm Files specific to IVMS8/IVML24 boards
154- board/lantec Files specific to LANTEC boards
155- board/lwmon Files specific to LWMON boards
156- board/mbx8xx Files specific to MBX boards
157- board/mpc8260ads
158 Files specific to MMPC8260ADS boards
159- board/mpl/ Files specific to boards manufactured by MPL
160- board/mpl/common Common files for MPL boards
161- board/mpl/pip405 Files specific to PIP405 boards
162- board/mpl/mip405 Files specific to MIP405 boards
163- board/musenki Files specific to MUSEKNI boards
164- board/mvs1 Files specific to MVS1 boards
165- board/nx823 Files specific to NX823 boards
166- board/oxc Files specific to OXC boards
167- board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
168- board/pm826 Files specific to PM826 boards
169- board/ppmc8260
170 Files specific to PPMC8260 boards
171- board/rpxsuper
172 Files specific to RPXsuper boards
173- board/rsdproto
174 Files specific to RSDproto boards
175- board/sandpoint
176 Files specific to Sandpoint boards
177- board/sbc8260 Files specific to SBC8260 boards
178- board/sacsng Files specific to SACSng boards
179- board/siemens Files specific to boards manufactured by Siemens AG
180- board/siemens/CCM Files specific to CCM boards
181- board/siemens/IAD210 Files specific to IAD210 boards
182- board/siemens/SCM Files specific to SCM boards
183- board/siemens/pcu_e Files specific to PCU_E boards
184- board/sixnet Files specific to SIXNET boards
185- board/spd8xx Files specific to SPD8xxTS boards
186- board/tqm8260 Files specific to TQM8260 boards
187- board/tqm8xx Files specific to TQM8xxL boards
188- board/w7o Files specific to W7O boards
189- board/walnut405
190 Files specific to Walnut405 boards
191- board/westel/ Files specific to boards manufactured by Westel Wireless
192- board/westel/amx860 Files specific to AMX860 boards
193- board/utx8245 Files specific to UTX8245 boards
194
195Software Configuration:
196=======================
197
198Configuration is usually done using C preprocessor defines; the
199rationale behind that is to avoid dead code whenever possible.
200
201There are two classes of configuration variables:
202
203* Configuration _OPTIONS_:
204 These are selectable by the user and have names beginning with
205 "CONFIG_".
206
207* Configuration _SETTINGS_:
208 These depend on the hardware etc. and should not be meddled with if
209 you don't know what you're doing; they have names beginning with
210 "CFG_".
211
212Later we will add a configuration tool - probably similar to or even
213identical to what's used for the Linux kernel. Right now, we have to
214do the configuration by hand, which means creating some symbolic
215links and editing some configuration files. We use the TQM8xxL boards
216as an example here.
217
218
219Selection of Processor Architecture and Board Type:
220---------------------------------------------------
221
222For all supported boards there are ready-to-use default
223configurations available; just type "make <board_name>_config".
224
225Example: For a TQM823L module type:
226
227 cd u-boot
228 make TQM823L_config
229
230For the Cogent platform, you need to specify the cpu type as well;
231e.g. "make cogent_mpc8xx_config". And also configure the cogent
232directory according to the instructions in cogent/README.
233
234
235Configuration Options:
236----------------------
237
238Configuration depends on the combination of board and CPU type; all
239such information is kept in a configuration file
240"include/configs/<board_name>.h".
241
242Example: For a TQM823L module, all configuration settings are in
243"include/configs/TQM823L.h".
244
245
246The following options need to be configured:
247
248- CPU Type: Define exactly one of
249
250 PowerPC based CPUs:
251 -------------------
252 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
253 or CONFIG_MPC824X, CONFIG_MPC8260
254 or CONFIG_IOP480
255 or CONFIG_405GP
256 or CONFIG_440
257 or CONFIG_MPC74xx
258
259 ARM based CPUs:
260 ---------------
261 CONFIG_SA1110
262 CONFIG_ARM7
263 CONFIG_PXA250
264
265
266- Board Type: Define exactly one of
267
268 PowerPC based boards:
269 ---------------------
270
271 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
272 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
273 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
274 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
275 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
276 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
277 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
278 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
279 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
280 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
281 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
282 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
283 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
284 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
285 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
286 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
287 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
288 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
289 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
290 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
291 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
292 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
293 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
294 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
295 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
296 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
297 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
298 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
299 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
300 CONFIG_EBONY, CONFIG_sacsng
301
302 ARM based boards:
303 -----------------
304
305 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
306 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
307 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
308 CONFIG_TRAB
309
310
311- CPU Module Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA286_60_OLD
314--- FIXME --- not tested yet:
315 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
316 CONFIG_CMA287_23, CONFIG_CMA287_50
317
318- Motherboard Type: (if CONFIG_COGENT is defined)
319 Define exactly one of
320 CONFIG_CMA101, CONFIG_CMA102
321
322- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
323 Define one or more of
324 CONFIG_CMA302
325
326- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
327 Define one or more of
328 CONFIG_LCD_HEARTBEAT - update a character position on
329 the lcd display every second with
330 a "rotator" |\-/|\-/
331
332- MPC824X Family Member (if CONFIG_MPC824X is defined)
333 Define exactly one of
334 CONFIG_MPC8240, CONFIG_MPC8245
335
336- 8xx CPU Options: (if using an 8xx cpu)
337 Define one or more of
338 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
339 no 32KHz reference PIT/RTC clock
340
341- Clock Interface:
342 CONFIG_CLOCKS_IN_MHZ
343
344 U-Boot stores all clock information in Hz
345 internally. For binary compatibility with older Linux
346 kernels (which expect the clocks passed in the
347 bd_info data to be in MHz) the environment variable
348 "clocks_in_mhz" can be defined so that U-Boot
349 converts clock data to MHZ before passing it to the
350 Linux kernel.
351
352 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
353 "clocks_in_mhz=1" is automatically included in the
354 default environment.
355
356- Console Interface:
357 Depending on board, define exactly one serial port
358 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
359 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
360 console by defining CONFIG_8xx_CONS_NONE
361
362 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
363 port routines must be defined elsewhere
364 (i.e. serial_init(), serial_getc(), ...)
365
366 CONFIG_CFB_CONSOLE
367 Enables console device for a color framebuffer. Needs following
368 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
369 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
370 (default big endian)
371 VIDEO_HW_RECTFILL graphic chip supports
372 rectangle fill
373 (cf. smiLynxEM)
374 VIDEO_HW_BITBLT graphic chip supports
375 bit-blit (cf. smiLynxEM)
376 VIDEO_VISIBLE_COLS visible pixel columns
377 (cols=pitch)
378 VIDEO_VISIBLE_ROWS visible pixel rows
379 VIDEO_PIXEL_SIZE bytes per pixel
380 VIDEO_DATA_FORMAT graphic data format
381 (0-5, cf. cfb_console.c)
382 VIDEO_FB_ADRS framebuffer address
383 VIDEO_KBD_INIT_FCT keyboard int fct
384 (i.e. i8042_kbd_init())
385 VIDEO_TSTC_FCT test char fct
386 (i.e. i8042_tstc)
387 VIDEO_GETC_FCT get char fct
388 (i.e. i8042_getc)
389 CONFIG_CONSOLE_CURSOR cursor drawing on/off
390 (requires blink timer
391 cf. i8042.c)
392 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
393 CONFIG_CONSOLE_TIME display time/date info in
394 upper right corner
395 (requires CFG_CMD_DATE)
396 CONFIG_VIDEO_LOGO display Linux logo in
397 upper left corner
398 CONFIG_CONSOLE_EXTRA_INFO
399 addional board info beside
400 the logo
401
402 When CONFIG_CFB_CONSOLE is defined, video console is
403 default i/o. Serial console can be forced with
404 environment 'console=serial'.
405
406- Console Baudrate:
407 CONFIG_BAUDRATE - in bps
408 Select one of the baudrates listed in
409 CFG_BAUDRATE_TABLE, see below.
410
411- Interrupt driven serial port input:
412 CONFIG_SERIAL_SOFTWARE_FIFO
413
414 PPC405GP only.
415 Use an interrupt handler for receiving data on the
416 serial port. It also enables using hardware handshake
417 (RTS/CTS) and UART's built-in FIFO. Set the number of
418 bytes the interrupt driven input buffer should have.
419
420 Set to 0 to disable this feature (this is the default).
421 This will also disable hardware handshake.
422
423- Boot Delay: CONFIG_BOOTDELAY - in seconds
424 Delay before automatically booting the default image;
425 set to -1 to disable autoboot.
426
427 See doc/README.autoboot for these options that
428 work with CONFIG_BOOTDELAY. None are required.
429 CONFIG_BOOT_RETRY_TIME
430 CONFIG_BOOT_RETRY_MIN
431 CONFIG_AUTOBOOT_KEYED
432 CONFIG_AUTOBOOT_PROMPT
433 CONFIG_AUTOBOOT_DELAY_STR
434 CONFIG_AUTOBOOT_STOP_STR
435 CONFIG_AUTOBOOT_DELAY_STR2
436 CONFIG_AUTOBOOT_STOP_STR2
437 CONFIG_ZERO_BOOTDELAY_CHECK
438 CONFIG_RESET_TO_RETRY
439
440- Autoboot Command:
441 CONFIG_BOOTCOMMAND
442 Only needed when CONFIG_BOOTDELAY is enabled;
443 define a command string that is automatically executed
444 when no character is read on the console interface
445 within "Boot Delay" after reset.
446
447 CONFIG_BOOTARGS
448 This can be used to pass arguments to the bootm
449 command. The value of CONFIG_BOOTARGS goes into the
450 environment value "bootargs".
451
452 CONFIG_RAMBOOT and CONFIG_NFSBOOT
453 The value of these goes into the environment as
454 "ramboot" and "nfsboot" respectively, and can be used
455 as a convenience, when switching between booting from
456 ram and nfs.
457
458- Pre-Boot Commands:
459 CONFIG_PREBOOT
460
461 When this option is #defined, the existence of the
462 environment variable "preboot" will be checked
463 immediately before starting the CONFIG_BOOTDELAY
464 countdown and/or running the auto-boot command resp.
465 entering interactive mode.
466
467 This feature is especially useful when "preboot" is
468 automatically generated or modified. For an example
469 see the LWMON board specific code: here "preboot" is
470 modified when the user holds down a certain
471 combination of keys on the (special) keyboard when
472 booting the systems
473
474- Serial Download Echo Mode:
475 CONFIG_LOADS_ECHO
476 If defined to 1, all characters received during a
477 serial download (using the "loads" command) are
478 echoed back. This might be needed by some terminal
479 emulations (like "cu"), but may as well just take
480 time on others. This setting #define's the initial
481 value of the "loads_echo" environment variable.
482
483- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
484 CONFIG_KGDB_BAUDRATE
485 Select one of the baudrates listed in
486 CFG_BAUDRATE_TABLE, see below.
487
488- Monitor Functions:
489 CONFIG_COMMANDS
490 Most monitor functions can be selected (or
491 de-selected) by adjusting the definition of
492 CONFIG_COMMANDS; to select individual functions,
493 #define CONFIG_COMMANDS by "OR"ing any of the
494 following values:
495
496 #define enables commands:
497 -------------------------
498 CFG_CMD_ASKENV * ask for env variable
499 CFG_CMD_BDI bdinfo
500 CFG_CMD_BEDBUG Include BedBug Debugger
501 CFG_CMD_BOOTD bootd
502 CFG_CMD_CACHE icache, dcache
503 CFG_CMD_CONSOLE coninfo
504 CFG_CMD_DATE * support for RTC, date/time...
505 CFG_CMD_DHCP DHCP support
506 CFG_CMD_ECHO * echo arguments
507 CFG_CMD_EEPROM * EEPROM read/write support
508 CFG_CMD_ELF bootelf, bootvx
509 CFG_CMD_ENV saveenv
510 CFG_CMD_FDC * Floppy Disk Support
511 CFG_CMD_FLASH flinfo, erase, protect
512 CFG_CMD_FPGA FPGA device initialization support
513 CFG_CMD_I2C * I2C serial bus support
514 CFG_CMD_IDE * IDE harddisk support
515 CFG_CMD_IMI iminfo
516 CFG_CMD_IMMAP * IMMR dump support
517 CFG_CMD_IRQ * irqinfo
518 CFG_CMD_KGDB * kgdb
519 CFG_CMD_LOADB loadb
520 CFG_CMD_LOADS loads
521 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
522 loop, mtest
523 CFG_CMD_MII MII utility commands
524 CFG_CMD_NET bootp, tftpboot, rarpboot
525 CFG_CMD_PCI * pciinfo
526 CFG_CMD_PCMCIA * PCMCIA support
527 CFG_CMD_REGINFO * Register dump
528 CFG_CMD_RUN run command in env variable
529 CFG_CMD_SCSI * SCSI Support
530 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
531 CFG_CMD_SPI * SPI serial bus support
532 CFG_CMD_USB * USB support
533 CFG_CMD_BSP * Board SPecific functions
534 -----------------------------------------------
535 CFG_CMD_ALL all
536
537 CFG_CMD_DFL Default configuration; at the moment
538 this is includes all commands, except
539 the ones marked with "*" in the list
540 above.
541
542 If you don't define CONFIG_COMMANDS it defaults to
543 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
544 override the default settings in the respective
545 include file.
546
547 EXAMPLE: If you want all functions except of network
548 support you can write:
549
550 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
551
552
553 Note: Don't enable the "icache" and "dcache" commands
554 (configuration option CFG_CMD_CACHE) unless you know
555 what you (and your U-Boot users) are doing. Data
556 cache cannot be enabled on systems like the 8xx or
557 8260 (where accesses to the IMMR region must be
558 uncached), and it cannot be disabled on all other
559 systems where we (mis-) use the data cache to hold an
560 initial stack and some data.
561
562
563 XXX - this list needs to get updated!
564
565- Watchdog:
566 CONFIG_WATCHDOG
567 If this variable is defined, it enables watchdog
568 support. There must support in the platform specific
569 code for a watchdog. For the 8xx and 8260 CPUs, the
570 SIU Watchdog feature is enabled in the SYPCR
571 register.
572
573- Real-Time Clock:
574
575 When CFG_CMD_DATE is selected, the type of the RTC
576 has to be selected, too. Define exactly one of the
577 following options:
578
579 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
580 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
581 CONFIG_RTC_MC146818 - use MC146818 RTC
582 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
583
584- Timestamp Support:
585
586 When CONFIG_TIMESTAMP is selected, the timestamp
587 (date and time) of an image is printed by image
588 commands like bootm or iminfo. This option is
589 automatically enabled when you select CFG_CMD_DATE .
590
591- Partition Support:
592 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
593 and/or CONFIG_ISO_PARTITION
594
595 If IDE or SCSI support is enabled (CFG_CMD_IDE or
596 CFG_CMD_SCSI) you must configure support for at least
597 one partition type as well.
598
599- IDE Reset method:
600 CONFIG_IDE_RESET_ROUTINE
601
602 Set this to define that instead of a reset Pin, the
603 routine ide_set_reset(int idereset) will be used.
604
605- ATAPI Support:
606 CONFIG_ATAPI
607
608 Set this to enable ATAPI support.
609
610- SCSI Support:
611 At the moment only there is only support for the
612 SYM53C8XX SCSI controller; define
613 CONFIG_SCSI_SYM53C8XX to enable it.
614
615 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
616 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
617 CFG_SCSI_MAX_LUN] can be adjusted to define the
618 maximum numbers of LUNs, SCSI ID's and target
619 devices.
620 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
621
622- NETWORK Support (PCI):
623 CONFIG_EEPRO100
624 Support for Intel 82557/82559/82559ER chips.
625 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
626 write routine for first time initialisation.
627
628 CONFIG_TULIP
629 Support for Digital 2114x chips.
630 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
631 modem chip initialisation (KS8761/QS6611).
632
633 CONFIG_NATSEMI
634 Support for National dp83815 chips.
635
636 CONFIG_NS8382X
637 Support for National dp8382[01] gigabit chips.
638
639- USB Support:
640 At the moment only the UHCI host controller is
641 supported (PIP405, MIP405); define
642 CONFIG_USB_UHCI to enable it.
643 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
644 end define CONFIG_USB_STORAGE to enable the USB
645 storage devices.
646 Note:
647 Supported are USB Keyboards and USB Floppy drives
648 (TEAC FD-05PUB).
649
650- Keyboard Support:
651 CONFIG_ISA_KEYBOARD
652
653 Define this to enable standard (PC-Style) keyboard
654 support
655
656 CONFIG_I8042_KBD
657 Standard PC keyboard driver with US (is default) and
658 GERMAN key layout (switch via environment 'keymap=de') support.
659 Export function i8042_kbd_init, i8042_tstc and i8042_getc
660 for cfb_console. Supports cursor blinking.
661
662- Video support:
663 CONFIG_VIDEO
664
665 Define this to enable video support (for output to
666 video).
667
668 CONFIG_VIDEO_CT69000
669
670 Enable Chips & Technologies 69000 Video chip
671
672 CONFIG_VIDEO_SMI_LYNXEM
673 Enable Silicon Motion SMI 712/710/810 Video chip
674 Videomode are selected via environment 'videomode' with
675 standard LiLo mode numbers.
676 Following modes are supported (* is default):
677
678 800x600 1024x768 1280x1024
679 256 (8bit) 303* 305 307
680 65536 (16bit) 314 317 31a
681 16,7 Mill (24bit) 315 318 31b
682 (i.e. setenv videomode 317; saveenv; reset;)
683
684- LCD Support: CONFIG_LCD
685
686 Define this to enable LCD support (for output to LCD
687 display); also select one of the supported displays
688 by defining one of these:
689
690 CONFIG_NEC_NL6648AC33:
691
692 NEC NL6648AC33-18. Active, color, single scan.
693
694 CONFIG_NEC_NL6648BC20
695
696 NEC NL6648BC20-08. 6.5", 640x480.
697 Active, color, single scan.
698
699 CONFIG_SHARP_16x9
700
701 Sharp 320x240. Active, color, single scan.
702 It isn't 16x9, and I am not sure what it is.
703
704 CONFIG_SHARP_LQ64D341
705
706 Sharp LQ64D341 display, 640x480.
707 Active, color, single scan.
708
709 CONFIG_HLD1045
710
711 HLD1045 display, 640x480.
712 Active, color, single scan.
713
714 CONFIG_OPTREX_BW
715
716 Optrex CBL50840-2 NF-FW 99 22 M5
717 or
718 Hitachi LMG6912RPFC-00T
719 or
720 Hitachi SP14Q002
721
722 320x240. Black & white.
723
724 Normally display is black on white background; define
725 CFG_WHITE_ON_BLACK to get it inverted.
726
727- Ethernet address:
728 CONFIG_ETHADDR
729 CONFIG_ETH2ADDR
730 CONFIG_ETH3ADDR
731
732 Define a default value for ethernet address to use
733 for the respective ethernet interface, in case this
734 is not determined automatically.
735
736- IP address:
737 CONFIG_IPADDR
738
739 Define a default value for the IP address to use for
740 the default ethernet interface, in case this is not
741 determined through e.g. bootp.
742
743- Server IP address:
744 CONFIG_SERVERIP
745
746 Defines a default value for theIP address of a TFTP
747 server to contact when using the "tftboot" command.
748
749- BOOTP Recovery Mode:
750 CONFIG_BOOTP_RANDOM_DELAY
751
752 If you have many targets in a network that try to
753 boot using BOOTP, you may want to avoid that all
754 systems send out BOOTP requests at precisely the same
755 moment (which would happen for instance at recovery
756 from a power failure, when all systems will try to
757 boot, thus flooding the BOOTP server. Defining
758 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
759 inserted before sending out BOOTP requests. The
760 following delays are insterted then:
761
762 1st BOOTP request: delay 0 ... 1 sec
763 2nd BOOTP request: delay 0 ... 2 sec
764 3rd BOOTP request: delay 0 ... 4 sec
765 4th and following
766 BOOTP requests: delay 0 ... 8 sec
767
768- Status LED: CONFIG_STATUS_LED
769
770 Several configurations allow to display the current
771 status using a LED. For instance, the LED will blink
772 fast while running U-Boot code, stop blinking as
773 soon as a reply to a BOOTP request was received, and
774 start blinking slow once the Linux kernel is running
775 (supported by a status LED driver in the Linux
776 kernel). Defining CONFIG_STATUS_LED enables this
777 feature in U-Boot.
778
779- CAN Support: CONFIG_CAN_DRIVER
780
781 Defining CONFIG_CAN_DRIVER enables CAN driver support
782 on those systems that support this (optional)
783 feature, like the TQM8xxL modules.
784
785- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
786
787 Enables I2C serial bus commands. If this is selected,
788 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
789 to include the appropriate I2C driver.
790
791 See also: common/cmd_i2c.c for a description of the
792 command line interface.
793
794
795 CONFIG_HARD_I2C
796
797 Selects the CPM hardware driver for I2C.
798
799 CONFIG_SOFT_I2C
800
801 Use software (aka bit-banging) driver instead of CPM
802 or similar hardware support for I2C. This is configured
803 via the following defines.
804
805 I2C_INIT
806
807 (Optional). Any commands necessary to enable I2C
808 controller or configure ports.
809
810 I2C_PORT
811
812 (Only for MPC8260 CPU). The I/O port to use (the code
813 assumes both bits are on the same port). Valid values
814 are 0..3 for ports A..D.
815
816 I2C_ACTIVE
817
818 The code necessary to make the I2C data line active
819 (driven). If the data line is open collector, this
820 define can be null.
821
822 I2C_TRISTATE
823
824 The code necessary to make the I2C data line tri-stated
825 (inactive). If the data line is open collector, this
826 define can be null.
827
828 I2C_READ
829
830 Code that returns TRUE if the I2C data line is high,
831 FALSE if it is low.
832
833 I2C_SDA(bit)
834
835 If <bit> is TRUE, sets the I2C data line high. If it
836 is FALSE, it clears it (low).
837
838 I2C_SCL(bit)
839
840 If <bit> is TRUE, sets the I2C clock line high. If it
841 is FALSE, it clears it (low).
842
843 I2C_DELAY
844
845 This delay is invoked four times per clock cycle so this
846 controls the rate of data transfer. The data rate thus
847 is 1 / (I2C_DELAY * 4).
848
849- SPI Support: CONFIG_SPI
850
851 Enables SPI driver (so far only tested with
852 SPI EEPROM, also an instance works with Crystal A/D and
853 D/As on the SACSng board)
854
855 CONFIG_SPI_X
856
857 Enables extended (16-bit) SPI EEPROM addressing.
858 (symmetrical to CONFIG_I2C_X)
859
860 CONFIG_SOFT_SPI
861
862 Enables a software (bit-bang) SPI driver rather than
863 using hardware support. This is a general purpose
864 driver that only requires three general I/O port pins
865 (two outputs, one input) to function. If this is
866 defined, the board configuration must define several
867 SPI configuration items (port pins to use, etc). For
868 an example, see include/configs/sacsng.h.
869
870- FPGA Support: CONFIG_FPGA_COUNT
871
872 Specify the number of FPGA devices to support.
873
874 CONFIG_FPGA
875
876 Used to specify the types of FPGA devices. For
877 example,
878 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
879
880 CFG_FPGA_PROG_FEEDBACK
881
882 Enable printing of hash marks during FPGA
883 configuration.
884
885 CFG_FPGA_CHECK_BUSY
886
887 Enable checks on FPGA configuration interface busy
888 status by the configuration function. This option
889 will require a board or device specific function to
890 be written.
891
892 CONFIG_FPGA_DELAY
893
894 If defined, a function that provides delays in the
895 FPGA configuration driver.
896
897 CFG_FPGA_CHECK_CTRLC
898
899 Allow Control-C to interrupt FPGA configuration
900
901 CFG_FPGA_CHECK_ERROR
902
903 Check for configuration errors during FPGA bitfile
904 loading. For example, abort during Virtex II
905 configuration if the INIT_B line goes low (which
906 indicated a CRC error).
907
908 CFG_FPGA_WAIT_INIT
909
910 Maximum time to wait for the INIT_B line to deassert
911 after PROB_B has been deasserted during a Virtex II
912 FPGA configuration sequence. The default time is 500 mS.
913
914 CFG_FPGA_WAIT_BUSY
915
916 Maximum time to wait for BUSY to deassert during
917 Virtex II FPGA configuration. The default is 5 mS.
918
919 CFG_FPGA_WAIT_CONFIG
920
921 Time to wait after FPGA configuration. The default is
922 200 mS.
923
924- FPGA Support: CONFIG_FPGA_COUNT
925
926 Specify the number of FPGA devices to support.
927
928 CONFIG_FPGA
929
930 Used to specify the types of FPGA devices. For example,
931 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
932
933 CFG_FPGA_PROG_FEEDBACK
934
935 Enable printing of hash marks during FPGA configuration.
936
937 CFG_FPGA_CHECK_BUSY
938
939 Enable checks on FPGA configuration interface busy
940 status by the configuration function. This option
941 will require a board or device specific function to
942 be written.
943
944 CONFIG_FPGA_DELAY
945
946 If defined, a function that provides delays in the FPGA
947 configuration driver.
948
949 CFG_FPGA_CHECK_CTRLC
950 Allow Control-C to interrupt FPGA configuration
951
952 CFG_FPGA_CHECK_ERROR
953
954 Check for configuration errors during FPGA bitfile
955 loading. For example, abort during Virtex II
956 configuration if the INIT_B line goes low (which
957 indicated a CRC error).
958
959 CFG_FPGA_WAIT_INIT
960
961 Maximum time to wait for the INIT_B line to deassert
962 after PROB_B has been deasserted during a Virtex II
963 FPGA configuration sequence. The default time is 500
964 mS.
965
966 CFG_FPGA_WAIT_BUSY
967
968 Maximum time to wait for BUSY to deassert during
969 Virtex II FPGA configuration. The default is 5 mS.
970
971 CFG_FPGA_WAIT_CONFIG
972
973 Time to wait after FPGA configuration. The default is
974 200 mS.
975
976- Configuration Management:
977 CONFIG_IDENT_STRING
978
979 If defined, this string will be added to the U-Boot
980 version information (U_BOOT_VERSION)
981
982- Vendor Parameter Protection:
983
984 U-Boot considers the values of the environment
985 variables "serial#" (Board Serial Number) and
986 "ethaddr" (Ethernet Address) to bb parameters that
987 are set once by the board vendor / manufacturer, and
988 protects these variables from casual modification by
989 the user. Once set, these variables are read-only,
990 and write or delete attempts are rejected. You can
991 change this behviour:
992
993 If CONFIG_ENV_OVERWRITE is #defined in your config
994 file, the write protection for vendor parameters is
995 completely disabled. Anybody can change or delte
996 these parameters.
997
998 Alternatively, if you #define _both_ CONFIG_ETHADDR
999 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1000 ethernet address is installed in the environment,
1001 which can be changed exactly ONCE by the user. [The
1002 serial# is unaffected by this, i. e. it remains
1003 read-only.]
1004
1005- Protected RAM:
1006 CONFIG_PRAM
1007
1008 Define this variable to enable the reservation of
1009 "protected RAM", i. e. RAM which is not overwritten
1010 by U-Boot. Define CONFIG_PRAM to hold the number of
1011 kB you want to reserve for pRAM. You can overwrite
1012 this default value by defining an environment
1013 variable "pram" to the number of kB you want to
1014 reserve. Note that the board info structure will
1015 still show the full amount of RAM. If pRAM is
1016 reserved, a new environment variable "mem" will
1017 automatically be defined to hold the amount of
1018 remaining RAM in a form that can be passed as boot
1019 argument to Linux, for instance like that:
1020
1021 setenv bootargs ... mem=\$(mem)
1022 saveenv
1023
1024 This way you can tell Linux not to use this memory,
1025 either, which results in a memory region that will
1026 not be affected by reboots.
1027
1028 *WARNING* If your board configuration uses automatic
1029 detection of the RAM size, you must make sure that
1030 this memory test is non-destructive. So far, the
1031 following board configurations are known to be
1032 "pRAM-clean":
1033
1034 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1035 HERMES, IP860, RPXlite, LWMON, LANTEC,
1036 PCU_E, FLAGADM, TQM8260
1037
1038- Error Recovery:
1039 CONFIG_PANIC_HANG
1040
1041 Define this variable to stop the system in case of a
1042 fatal error, so that you have to reset it manually.
1043 This is probably NOT a good idea for an embedded
1044 system where you want to system to reboot
1045 automatically as fast as possible, but it may be
1046 useful during development since you can try to debug
1047 the conditions that lead to the situation.
1048
1049 CONFIG_NET_RETRY_COUNT
1050
1051 This variable defines the number of retries for
1052 network operations like ARP, RARP, TFTP, or BOOTP
1053 before giving up the operation. If not defined, a
1054 default value of 5 is used.
1055
1056- Command Interpreter:
1057 CFG_HUSH_PARSER
1058
1059 Define this variable to enable the "hush" shell (from
1060 Busybox) as command line interpreter, thus enabling
1061 powerful command line syntax like
1062 if...then...else...fi conditionals or `&&' and '||'
1063 constructs ("shell scripts").
1064
1065 If undefined, you get the old, much simpler behaviour
1066 with a somewhat smaller memory footprint.
1067
1068
1069 CFG_PROMPT_HUSH_PS2
1070
1071 This defines the secondary prompt string, which is
1072 printed when the command interpreter needs more input
1073 to complete a command. Usually "> ".
1074
1075 Note:
1076
1077 In the current implementation, the local variables
1078 space and global environment variables space are
1079 separated. Local variables are those you define by
1080 simply typing like `name=value'. To access a local
1081 variable later on, you have write `$name' or
1082 `${name}'; variable directly by typing say `$name' at
1083 the command prompt.
1084
1085 Global environment variables are those you use
1086 setenv/printenv to work with. To run a command stored
1087 in such a variable, you need to use the run command,
1088 and you must not use the '$' sign to access them.
1089
1090 To store commands and special characters in a
1091 variable, please use double quotation marks
1092 surrounding the whole text of the variable, instead
1093 of the backslashes before semicolons and special
1094 symbols.
1095
1096- Default Environment
1097 CONFIG_EXTRA_ENV_SETTINGS
1098
1099 Define this to contain any number of null terminated
1100 strings (variable = value pairs) that will be part of
1101 the default enviroment compiled into the boot image.
1102 For example, place something like this in your
1103 board's config file:
1104
1105 #define CONFIG_EXTRA_ENV_SETTINGS \
1106 "myvar1=value1\0" \
1107 "myvar2=value2\0"
1108
1109 Warning: This method is based on knowledge about the
1110 internal format how the environment is stored by the
1111 U-Boot code. This is NOT an official, expoerted
1112 interface! Although it is unlikely that this format
1113 will change soon, there is no guarantee either.
1114 You better know what you are doing here.
1115
1116 Note: overly (ab)use of the default environment is
1117 discouraged. Make sure to check other ways to preset
1118 the environment like the autoscript function or the
1119 boot command first.
1120
1121- Show boot progress
1122 CONFIG_SHOW_BOOT_PROGRESS
1123
1124 Defining this option allows to add some board-
1125 specific code (calling a user-provided function
1126 "show_boot_progress(int)") that enables you to show
1127 the system's boot progress on some display (for
1128 example, some LED's) on your board. At the moment,
1129 the following checkpoints are implemented:
1130
1131 Arg Where When
1132 1 common/cmd_bootm.c before attempting to boot an image
1133 -1 common/cmd_bootm.c Image header has bad magic number
1134 2 common/cmd_bootm.c Image header has correct magic number
1135 -2 common/cmd_bootm.c Image header has bad checksum
1136 3 common/cmd_bootm.c Image header has correct checksum
1137 -3 common/cmd_bootm.c Image data has bad checksum
1138 4 common/cmd_bootm.c Image data has correct checksum
1139 -4 common/cmd_bootm.c Image is for unsupported architecture
1140 5 common/cmd_bootm.c Architecture check OK
1141 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1142 6 common/cmd_bootm.c Image Type check OK
1143 -6 common/cmd_bootm.c gunzip uncompression error
1144 -7 common/cmd_bootm.c Unimplemented compression type
1145 7 common/cmd_bootm.c Uncompression OK
1146 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1147 8 common/cmd_bootm.c Image Type check OK
1148 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1149 9 common/cmd_bootm.c Start initial ramdisk verification
1150 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1151 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1152 10 common/cmd_bootm.c Ramdisk header is OK
1153 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1154 11 common/cmd_bootm.c Ramdisk data has correct checksum
1155 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1156 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1157 13 common/cmd_bootm.c Start multifile image verification
1158 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1159 15 common/cmd_bootm.c All preparation done, transferring control to OS
1160
1161 -1 common/cmd_doc.c Bad usage of "doc" command
1162 -1 common/cmd_doc.c No boot device
1163 -1 common/cmd_doc.c Unknown Chip ID on boot device
1164 -1 common/cmd_doc.c Read Error on boot device
1165 -1 common/cmd_doc.c Image header has bad magic number
1166
1167 -1 common/cmd_ide.c Bad usage of "ide" command
1168 -1 common/cmd_ide.c No boot device
1169 -1 common/cmd_ide.c Unknown boot device
1170 -1 common/cmd_ide.c Unknown partition table
1171 -1 common/cmd_ide.c Invalid partition type
1172 -1 common/cmd_ide.c Read Error on boot device
1173 -1 common/cmd_ide.c Image header has bad magic number
1174
1175 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1176
1177
1178Modem Support:
1179--------------
1180
1181[so far only for SMDK2400 board]
1182
1183- Modem support endable:
1184 CONFIG_MODEM_SUPPORT
1185
1186- RTS/CTS Flow control enable:
1187 CONFIG_HWFLOW
1188
1189- Modem debug support:
1190 CONFIG_MODEM_SUPPORT_DEBUG
1191
1192 Enables debugging stuff (char screen[1024], dbg())
1193 for modem support. Useful only with BDI2000.
1194
1195- General:
1196
1197 In the target system modem support is enabled when a
1198 specific key (key combination) is pressed during
1199 power-on. Otherwise U-Boot will boot normally
1200 (autoboot). The key_pressed() fuction is called from
1201 board_init(). Currently key_pressed() is a dummy
1202 function, returning 1 and thus enabling modem
1203 initialization.
1204
1205 If there are no modem init strings in the
1206 environment, U-Boot proceed to autoboot; the
1207 previous output (banner, info printfs) will be
1208 supressed, though.
1209
1210 See also: doc/README.Modem
1211
1212
1213
1214
1215Configuration Settings:
1216-----------------------
1217
1218- CFG_LONGHELP: Defined when you want long help messages included;
1219 undefine this when you're short of memory.
1220
1221- CFG_PROMPT: This is what U-Boot prints on the console to
1222 prompt for user input.
1223
1224- CFG_CBSIZE: Buffer size for input from the Console
1225
1226- CFG_PBSIZE: Buffer size for Console output
1227
1228- CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1229
1230- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1231 the application (usually a Linux kernel) when it is
1232 booted
1233
1234- CFG_BAUDRATE_TABLE:
1235 List of legal baudrate settings for this board.
1236
1237- CFG_CONSOLE_INFO_QUIET
1238 Suppress display of console information at boot.
1239
1240- CFG_CONSOLE_IS_IN_ENV
1241 If the board specific function
1242 extern int overwrite_console (void);
1243 returns 1, the stdin, stderr and stdout are switched to the
1244 serial port, else the settings in the environment are used.
1245
1246- CFG_CONSOLE_OVERWRITE_ROUTINE
1247 Enable the call to overwrite_console().
1248
1249- CFG_CONSOLE_ENV_OVERWRITE
1250 Enable overwrite of previous console environment settings.
1251
1252- CFG_MEMTEST_START, CFG_MEMTEST_END:
1253 Begin and End addresses of the area used by the
1254 simple memory test.
1255
1256- CFG_ALT_MEMTEST:
1257 Enable an alternate, more extensive memory test.
1258
1259- CFG_TFTP_LOADADDR:
1260 Default load address for network file downloads
1261
1262- CFG_LOADS_BAUD_CHANGE:
1263 Enable temporary baudrate change while serial download
1264
1265- CFG_SDRAM_BASE:
1266 Physical start address of SDRAM. _Must_ be 0 here.
1267
1268- CFG_MBIO_BASE:
1269 Physical start address of Motherboard I/O (if using a
1270 Cogent motherboard)
1271
1272- CFG_FLASH_BASE:
1273 Physical start address of Flash memory.
1274
1275- CFG_MONITOR_BASE:
1276 Physical start address of boot monitor code (set by
1277 make config files to be same as the text base address
1278 (TEXT_BASE) used when linking) - same as
1279 CFG_FLASH_BASE when booting from flash.
1280
1281- CFG_MONITOR_LEN:
1282 Size of memory reserved for monitor code
1283
1284- CFG_MALLOC_LEN:
1285 Size of DRAM reserved for malloc() use.
1286
1287- CFG_BOOTMAPSZ:
1288 Maximum size of memory mapped by the startup code of
1289 the Linux kernel; all data that must be processed by
1290 the Linux kernel (bd_info, boot arguments, eventually
1291 initrd image) must be put below this limit.
1292
1293- CFG_MAX_FLASH_BANKS:
1294 Max number of Flash memory banks
1295
1296- CFG_MAX_FLASH_SECT:
1297 Max number of sectors on a Flash chip
1298
1299- CFG_FLASH_ERASE_TOUT:
1300 Timeout for Flash erase operations (in ms)
1301
1302- CFG_FLASH_WRITE_TOUT:
1303 Timeout for Flash write operations (in ms)
1304
1305- CFG_DIRECT_FLASH_TFTP:
1306
1307 Enable TFTP transfers directly to flash memory;
1308 without this option such a download has to be
1309 performed in two steps: (1) download to RAM, and (2)
1310 copy from RAM to flash.
1311
1312 The two-step approach is usually more reliable, since
1313 you can check if the download worked before you erase
1314 the flash, but in some situations (when sytem RAM is
1315 too limited to allow for a tempory copy of the
1316 downloaded image) this option may be very useful.
1317
1318- CFG_FLASH_CFI:
1319 Define if the flash driver uses extra elements in the
1320 common flash structure for storing flash geometry
1321
1322The following definitions that deal with the placement and management
1323of environment data (variable area); in general, we support the
1324following configurations:
1325
1326- CFG_ENV_IS_IN_FLASH:
1327
1328 Define this if the environment is in flash memory.
1329
1330 a) The environment occupies one whole flash sector, which is
1331 "embedded" in the text segment with the U-Boot code. This
1332 happens usually with "bottom boot sector" or "top boot
1333 sector" type flash chips, which have several smaller
1334 sectors at the start or the end. For instance, such a
1335 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1336 such a case you would place the environment in one of the
1337 4 kB sectors - with U-Boot code before and after it. With
1338 "top boot sector" type flash chips, you would put the
1339 environment in one of the last sectors, leaving a gap
1340 between U-Boot and the environment.
1341
1342 - CFG_ENV_OFFSET:
1343
1344 Offset of environment data (variable area) to the
1345 beginning of flash memory; for instance, with bottom boot
1346 type flash chips the second sector can be used: the offset
1347 for this sector is given here.
1348
1349 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1350
1351 - CFG_ENV_ADDR:
1352
1353 This is just another way to specify the start address of
1354 the flash sector containing the environment (instead of
1355 CFG_ENV_OFFSET).
1356
1357 - CFG_ENV_SECT_SIZE:
1358
1359 Size of the sector containing the environment.
1360
1361
1362 b) Sometimes flash chips have few, equal sized, BIG sectors.
1363 In such a case you don't want to spend a whole sector for
1364 the environment.
1365
1366 - CFG_ENV_SIZE:
1367
1368 If you use this in combination with CFG_ENV_IS_IN_FLASH
1369 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1370 of this flash sector for the environment. This saves
1371 memory for the RAM copy of the environment.
1372
1373 It may also save flash memory if you decide to use this
1374 when your environment is "embedded" within U-Boot code,
1375 since then the remainder of the flash sector could be used
1376 for U-Boot code. It should be pointed out that this is
1377 STRONGLY DISCOURAGED from a robustness point of view:
1378 updating the environment in flash makes it always
1379 necessary to erase the WHOLE sector. If something goes
1380 wrong before the contents has been restored from a copy in
1381 RAM, your target system will be dead.
1382
1383 - CFG_ENV_ADDR_REDUND
1384 CFG_ENV_SIZE_REDUND
1385
1386 These settings describe a second storage area used to hold
1387 a redundand copy of the environment data, so that there is
1388 a valid backup copy in case there is a power failur during
1389 a "saveenv" operation.
1390
1391BE CAREFUL! Any changes to the flash layout, and some changes to the
1392source code will make it necessary to adapt <board>/u-boot.lds*
1393accordingly!
1394
1395
1396- CFG_ENV_IS_IN_NVRAM:
1397
1398 Define this if you have some non-volatile memory device
1399 (NVRAM, battery buffered SRAM) which you want to use for the
1400 environment.
1401
1402 - CFG_ENV_ADDR:
1403 - CFG_ENV_SIZE:
1404
1405 These two #defines are used to determin the memory area you
1406 want to use for environment. It is assumed that this memory
1407 can just be read and written to, without any special
1408 provision.
1409
1410BE CAREFUL! The first access to the environment happens quite early
1411in U-Boot initalization (when we try to get the setting of for the
1412console baudrate). You *MUST* have mappend your NVRAM area then, or
1413U-Boot will hang.
1414
1415Please note that even with NVRAM we still use a copy of the
1416environment in RAM: we could work on NVRAM directly, but we want to
1417keep settings there always unmodified except somebody uses "saveenv"
1418to save the current settings.
1419
1420
1421- CFG_ENV_IS_IN_EEPROM:
1422
1423 Use this if you have an EEPROM or similar serial access
1424 device and a driver for it.
1425
1426 - CFG_ENV_OFFSET:
1427 - CFG_ENV_SIZE:
1428
1429 These two #defines specify the offset and size of the
1430 environment area within the total memory of your EEPROM.
1431
1432 - CFG_I2C_EEPROM_ADDR:
1433 If defined, specified the chip address of the EEPROM device.
1434 The default address is zero.
1435
1436 - CFG_EEPROM_PAGE_WRITE_BITS:
1437 If defined, the number of bits used to address bytes in a
1438 single page in the EEPROM device. A 64 byte page, for example
1439 would require six bits.
1440
1441 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1442 If defined, the number of milliseconds to delay between
1443 page writes. The default is zero milliseconds.
1444
1445 - CFG_I2C_EEPROM_ADDR_LEN:
1446 The length in bytes of the EEPROM memory array address. Note
1447 that this is NOT the chip address length!
1448
1449 - CFG_EEPROM_SIZE:
1450 The size in bytes of the EEPROM device.
1451
1452 - CFG_I2C_EEPROM_ADDR:
1453 If defined, specified the chip address of the EEPROM device.
1454 The default address is zero.
1455
1456 - CFG_EEPROM_PAGE_WRITE_BITS:
1457 If defined, the number of bits used to address bytes in a
1458 single page in the EEPROM device. A 64 byte page, for example
1459 would require six bits.
1460
1461 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1462 If defined, the number of milliseconds to delay between
1463 page writes. The default is zero milliseconds.
1464
1465 - CFG_I2C_EEPROM_ADDR_LEN:
1466 The length in bytes of the EEPROM memory array address. Note
1467 that this is NOT the chip address length!
1468
1469 - CFG_EEPROM_SIZE:
1470 The size in bytes of the EEPROM device.
1471
1472- CFG_SPI_INIT_OFFSET
1473
1474 Defines offset to the initial SPI buffer area in DPRAM. The
1475 area is used at an early stage (ROM part) if the environment
1476 is configured to reside in the SPI EEPROM: We need a 520 byte
1477 scratch DPRAM area. It is used between the two initialization
1478 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1479 to be a good choice since it makes it far enough from the
1480 start of the data area as well as from the stack pointer.
1481
1482Please note that the environment is read-only as long as the monitor
1483has been relocated to RAM and a RAM copy of the environment has been
1484created; also, when using EEPROM you will have to use getenv_r()
1485until then to read environment variables.
1486
1487The environment is now protected by a CRC32 checksum. Before the
1488monitor is relocated into RAM, as a result of a bad CRC you will be
1489working with the compiled-in default environment - *silently*!!!
1490[This is necessary, because the first environment variable we need is
1491the "baudrate" setting for the console - if we have a bad CRC, we
1492don't have any device yet where we could complain.]
1493
1494Note: once the monitor has been relocated, then it will complain if
1495the default environment is used; a new CRC is computed as soon as you
1496use the "setenv" command to modify / delete / add any environment
1497variable [even when you try to delete a non-existing variable!].
1498
1499Note2: you must edit your u-boot.lds file to reflect this
1500configuration.
1501
1502
1503Many of the options are named exactly as the corresponding Linux
1504kernel configuration options. The intention is to make it easier to
1505build a config tool - later.
1506
1507Low Level (hardware related) configuration options:
1508
1509- CFG_CACHELINE_SIZE:
1510 Cache Line Size of the CPU.
1511
1512- CFG_DEFAULT_IMMR:
1513 Default address of the IMMR after system reset.
1514 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1515 to be able to adjust the position of the IMMR
1516 register after a reset.
1517
1518- CFG_IMMR: Physical address of the Internal Memory Mapped
1519 Register; DO NOT CHANGE! (11-4)
1520 [MPC8xx systems only]
1521
1522- CFG_INIT_RAM_ADDR:
1523
1524 Start address of memory area tha can be used for
1525 initial data and stack; please note that this must be
1526 writable memory that is working WITHOUT special
1527 initialization, i. e. you CANNOT use normal RAM which
1528 will become available only after programming the
1529 memory controller and running certain initialization
1530 sequences.
1531
1532 U-Boot uses the following memory types:
1533 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1534 - MPC824X: data cache
1535 - PPC4xx: data cache
1536
1537- CFG_INIT_DATA_OFFSET:
1538
1539 Offset of the initial data structure in the memory
1540 area defined by CFG_INIT_RAM_ADDR. Usually
1541 CFG_INIT_DATA_OFFSET is chosen such that the initial
1542 data is located at the end of the available space
1543 (sometimes written as (CFG_INIT_RAM_END -
1544 CFG_INIT_DATA_SIZE), and the initial stack is just
1545 below that area (growing from (CFG_INIT_RAM_ADDR +
1546 CFG_INIT_DATA_OFFSET) downward.
1547
1548 Note:
1549 On the MPC824X (or other systems that use the data
1550 cache for initial memory) the address chosen for
1551 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1552 point to an otherwise UNUSED address space between
1553 the top of RAM and the start of the PCI space.
1554
1555- CFG_SIUMCR: SIU Module Configuration (11-6)
1556
1557- CFG_SYPCR: System Protection Control (11-9)
1558
1559- CFG_TBSCR: Time Base Status and Control (11-26)
1560
1561- CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1562
1563- CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1564
1565- CFG_SCCR: System Clock and reset Control Register (15-27)
1566
1567- CFG_OR_TIMING_SDRAM:
1568 SDRAM timing
1569
1570- CFG_MAMR_PTA:
1571 periodic timer for refresh
1572
1573- CFG_DER: Debug Event Register (37-47)
1574
1575- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1576 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1577 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1578 CFG_BR1_PRELIM:
1579 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1580
1581- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1582 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1583 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1584 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1585
1586- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1587 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1588 Machine Mode Register and Memory Periodic Timer
1589 Prescaler definitions (SDRAM timing)
1590
1591- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1592 enable I2C microcode relocation patch (MPC8xx);
1593 define relocation offset in DPRAM [DSP2]
1594
1595- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1596 enable SPI microcode relocation patch (MPC8xx);
1597 define relocation offset in DPRAM [SCC4]
1598
1599- CFG_USE_OSCCLK:
1600 Use OSCM clock mode on MBX8xx board. Be careful,
1601 wrong setting might damage your board. Read
1602 doc/README.MBX before setting this variable!
1603
1604Building the Software:
1605======================
1606
1607Building U-Boot has been tested in native PPC environments (on a
1608PowerBook G3 running LinuxPPC 2000) and in cross environments
1609(running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1610NetBSD 1.5 on x86).
1611
1612If you are not using a native PPC environment, it is assumed that you
1613have the GNU cross compiling tools available in your path and named
1614with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1615you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1616the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1617change it to:
1618
1619 CROSS_COMPILE = ppc_4xx-
1620
1621
1622U-Boot is intended to be simple to build. After installing the
1623sources you must configure U-Boot for one specific board type. This
1624is done by typing:
1625
1626 make NAME_config
1627
1628where "NAME_config" is the name of one of the existing
1629configurations; the following names are supported:
1630
1631 ADCIOP_config GTH_config TQM850L_config
1632 ADS860_config IP860_config TQM855L_config
1633 AR405_config IVML24_config TQM860L_config
1634 CANBT_config IVMS8_config WALNUT405_config
1635 CPCI405_config LANTEC_config cogent_common_config
1636 CPCIISER4_config MBX_config cogent_mpc8260_config
1637 CU824_config MBX860T_config cogent_mpc8xx_config
1638 ESTEEM192E_config RPXlite_config hermes_config
1639 ETX094_config RPXsuper_config hymod_config
1640 FADS823_config SM850_config lwmon_config
1641 FADS850SAR_config SPD823TS_config pcu_e_config
1642 FADS860T_config SXNI855T_config rsdproto_config
1643 FPS850L_config Sandpoint8240_config sbc8260_config
1644 GENIETV_config TQM823L_config PIP405_config
1645 GEN860T_config EBONY_config
1646
1647Note: for some board special configuration names may exist; check if
1648 additional information is available from the board vendor; for
1649 instance, the TQM8xxL systems run normally at 50 MHz and use a
1650 SCC for 10baseT ethernet; there are also systems with 80 MHz
1651 CPU clock, and an optional Fast Ethernet module is available
1652 for CPU's with FEC. You can select such additional "features"
1653 when chosing the configuration, i. e.
1654
1655 make TQM860L_config
1656 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1657
1658 make TQM860L_FEC_config
1659 - will configure for a TQM860L at 50MHz with FEC for ethernet
1660
1661 make TQM860L_80MHz_config
1662 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1663 interface
1664
1665 make TQM860L_FEC_80MHz_config
1666 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1667
1668 make TQM823L_LCD_config
1669 - will configure for a TQM823L with U-Boot console on LCD
1670
1671 make TQM823L_LCD_80MHz_config
1672 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1673
1674 etc.
1675
1676
1677
1678Finally, type "make all", and you should get some working U-Boot
1679images ready for downlod to / installation on your system:
1680
1681- "u-boot.bin" is a raw binary image
1682- "u-boot" is an image in ELF binary format
1683- "u-boot.srec" is in Motorola S-Record format
1684
1685
1686Please be aware that the Makefiles assume you are using GNU make, so
1687for instance on NetBSD you might need to use "gmake" instead of
1688native "make".
1689
1690
1691If the system board that you have is not listed, then you will need
1692to port U-Boot to your hardware platform. To do this, follow these
1693steps:
1694
16951. Add a new configuration option for your board to the toplevel
1696 "Makefile", using the existing entries as examples.
16972. Create a new directory to hold your board specific code. Add any
1698 files you need.
16993. If you're porting U-Boot to a new CPU, then also create a new
1700 directory to hold your CPU specific code. Add any files you need.
17014. Run "make config_name" with your new name.
17025. Type "make", and you should get a working "u-boot.srec" file
1703 to be installed on your target system.
1704 [Of course, this last step is much harder than it sounds.]
1705
1706
1707Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1708==============================================================
1709
1710If you have modified U-Boot sources (for instance added a new board
1711or support for new devices, a new CPU, etc.) you are expected to
1712provide feedback to the other developers. The feedback normally takes
1713the form of a "patch", i. e. a context diff against a certain (latest
1714official or latest in CVS) version of U-Boot sources.
1715
1716But before you submit such a patch, please verify that your modifi-
1717cation did not break existing code. At least make sure that *ALL* of
1718the supported boards compile WITHOUT ANY compiler warnings. To do so,
1719just run the "MAKEALL" script, which will configure and build U-Boot
1720for ALL supported system. Be warned, this will take a while. You can
1721select which (cross) compiler to use py passing a `CROSS_COMPILE'
1722environment variable to the script, i. e. to use the cross tools from
1723MontaVista's Hard Hat Linux you can type
1724
1725 CROSS_COMPILE=ppc_8xx- MAKEALL
1726
1727or to build on a native PowerPC system you can type
1728
1729 CROSS_COMPILE=' ' MAKEALL
1730
1731See also "U-Boot Porting Guide" below.
1732
1733
1734
1735Monitor Commands - Overview:
1736============================
1737
1738go - start application at address 'addr'
1739run - run commands in an environment variable
1740bootm - boot application image from memory
1741bootp - boot image via network using BootP/TFTP protocol
1742tftpboot- boot image via network using TFTP protocol
1743 and env variables "ipaddr" and "serverip"
1744 (and eventually "gatewayip")
1745rarpboot- boot image via network using RARP/TFTP protocol
1746diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1747loads - load S-Record file over serial line
1748loadb - load binary file over serial line (kermit mode)
1749md - memory display
1750mm - memory modify (auto-incrementing)
1751nm - memory modify (constant address)
1752mw - memory write (fill)
1753cp - memory copy
1754cmp - memory compare
1755crc32 - checksum calculation
1756imd - i2c memory display
1757imm - i2c memory modify (auto-incrementing)
1758inm - i2c memory modify (constant address)
1759imw - i2c memory write (fill)
1760icrc32 - i2c checksum calculation
1761iprobe - probe to discover valid I2C chip addresses
1762iloop - infinite loop on address range
1763isdram - print SDRAM configuration information
1764sspi - SPI utility commands
1765base - print or set address offset
1766printenv- print environment variables
1767setenv - set environment variables
1768saveenv - save environment variables to persistent storage
1769protect - enable or disable FLASH write protection
1770erase - erase FLASH memory
1771flinfo - print FLASH memory information
1772bdinfo - print Board Info structure
1773iminfo - print header information for application image
1774coninfo - print console devices and informations
1775ide - IDE sub-system
1776loop - infinite loop on address range
1777mtest - simple RAM test
1778icache - enable or disable instruction cache
1779dcache - enable or disable data cache
1780reset - Perform RESET of the CPU
1781echo - echo args to console
1782version - print monitor version
1783help - print online help
1784? - alias for 'help'
1785
1786
1787Monitor Commands - Detailed Description:
1788========================================
1789
1790TODO.
1791
1792For now: just type "help <command>".
1793
1794
1795Environment Variables:
1796======================
1797
1798U-Boot supports user configuration using Environment Variables which
1799can be made persistent by saving to Flash memory.
1800
1801Environment Variables are set using "setenv", printed using
1802"printenv", and saved to Flash using "saveenv". Using "setenv"
1803without a value can be used to delete a variable from the
1804environment. As long as you don't save the environment you are
1805working with an in-memory copy. In case the Flash area containing the
1806environment is erased by accident, a default environment is provided.
1807
1808Some configuration options can be set using Environment Variables:
1809
1810 baudrate - see CONFIG_BAUDRATE
1811
1812 bootdelay - see CONFIG_BOOTDELAY
1813
1814 bootcmd - see CONFIG_BOOTCOMMAND
1815
1816 bootargs - Boot arguments when booting an RTOS image
1817
1818 bootfile - Name of the image to load with TFTP
1819
1820 autoload - if set to "no" (any string beginning with 'n'),
1821 "bootp" will just load perform a lookup of the
1822 configuration from the BOOTP server, but not try to
1823 load any image using TFTP
1824
1825 autostart - if set to "yes", an image loaded using the "bootp",
1826 "rarpboot", "tftpboot" or "diskboot" commands will
1827 be automatically started (by internally calling
1828 "bootm")
1829
1830 initrd_high - restrict positioning of initrd images:
1831 If this variable is not set, initrd images will be
1832 copied to the highest possible address in RAM; this
1833 is usually what you want since it allows for
1834 maximum initrd size. If for some reason you want to
1835 make sure that the initrd image is loaded below the
1836 CFG_BOOTMAPSZ limit, you can set this environment
1837 variable to a value of "no" or "off" or "0".
1838 Alternatively, you can set it to a maximum upper
1839 address to use (U-Boot will still check that it
1840 does not overwrite the U-Boot stack and data).
1841
1842 For instance, when you have a system with 16 MB
1843 RAM, and want to reseve 4 MB from use by Linux,
1844 you can do this by adding "mem=12M" to the value of
1845 the "bootargs" variable. However, now you must make
1846 sure, that the initrd image is placed in the first
1847 12 MB as well - this can be done with
1848
1849 setenv initrd_high 00c00000
1850
1851 ipaddr - IP address; needed for tftpboot command
1852
1853 loadaddr - Default load address for commands like "bootp",
1854 "rarpboot", "tftpboot" or "diskboot"
1855
1856 loads_echo - see CONFIG_LOADS_ECHO
1857
1858 serverip - TFTP server IP address; needed for tftpboot command
1859
1860 bootretry - see CONFIG_BOOT_RETRY_TIME
1861
1862 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
1863
1864 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
1865
1866
1867The following environment variables may be used and automatically
1868updated by the network boot commands ("bootp" and "rarpboot"),
1869depending the information provided by your boot server:
1870
1871 bootfile - see above
1872 dnsip - IP address of your Domain Name Server
1873 gatewayip - IP address of the Gateway (Router) to use
1874 hostname - Target hostname
1875 ipaddr - see above
1876 netmask - Subnet Mask
1877 rootpath - Pathname of the root filesystem on the NFS server
1878 serverip - see above
1879
1880
1881There are two special Environment Variables:
1882
1883 serial# - contains hardware identification information such
1884 as type string and/or serial number
1885 ethaddr - Ethernet address
1886
1887These variables can be set only once (usually during manufacturing of
1888the board). U-Boot refuses to delete or overwrite these variables
1889once they have been set once.
1890
1891
1892Please note that changes to some configuration parameters may take
1893only effect after the next boot (yes, that's just like Windoze :-).
1894
1895
1896Note for Redundant Ethernet Interfaces:
1897=======================================
1898
1899Some boards come with redundand ethernet interfaces; U-Boot supports
1900such configurations and is capable of automatic selection of a
1901"working" interface when needed. MAC assignemnt works as follows:
1902
1903Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
1904MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
1905"eth1addr" (=>eth1), "eth2addr", ...
1906
1907If the network interface stores some valid MAC address (for instance
1908in SROM), this is used as default address if there is NO correspon-
1909ding setting in the environment; if the corresponding environment
1910variable is set, this overrides the settings in the card; that means:
1911
1912o If the SROM has a valid MAC address, and there is no address in the
1913 environment, the SROM's address is used.
1914
1915o If there is no valid address in the SROM, and a definition in the
1916 environment exists, then the value from the environment variable is
1917 used.
1918
1919o If both the SROM and the environment contain a MAC address, and
1920 both addresses are the same, this MAC address is used.
1921
1922o If both the SROM and the environment contain a MAC address, and the
1923 addresses differ, the value from the environment is used and a
1924 warning is printed.
1925
1926o If neither SROM nor the environment contain a MAC address, an error
1927 is raised.
1928
1929
1930
1931Image Formats:
1932==============
1933
1934The "boot" commands of this monitor operate on "image" files which
1935can be basicly anything, preceeded by a special header; see the
1936definitions in include/image.h for details; basicly, the header
1937defines the following image properties:
1938
1939* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
1940 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
1941 LynxOS, pSOS, QNX;
1942 Currently supported: Linux, NetBSD, VxWorks, QNX).
1943* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
1944 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
1945 Currently supported: PowerPC).
1946* Compression Type (Provisions for uncompressed, gzip, bzip2;
1947 Currently supported: uncompressed, gzip).
1948* Load Address
1949* Entry Point
1950* Image Name
1951* Image Timestamp
1952
1953The header is marked by a special Magic Number, and both the header
1954and the data portions of the image are secured against corruption by
1955CRC32 checksums.
1956
1957
1958Linux Support:
1959==============
1960
1961Although U-Boot should support any OS or standalone application
1962easily, Linux has always been in the focus during the design of
1963U-Boot.
1964
1965U-Boot includes many features that so far have been part of some
1966special "boot loader" code within the Linux kernel. Also, any
1967"initrd" images to be used are no longer part of one big Linux image;
1968instead, kernel and "initrd" are separate images. This implementation
1969serves serveral purposes:
1970
1971- the same features can be used for other OS or standalone
1972 applications (for instance: using compressed images to reduce the
1973 Flash memory footprint)
1974
1975- it becomes much easier to port new Linux kernel versions because
1976 lots of low-level, hardware dependend stuff are done by U-Boot
1977
1978- the same Linux kernel image can now be used with different "initrd"
1979 images; of course this also means that different kernel images can
1980 be run with the same "initrd". This makes testing easier (you don't
1981 have to build a new "zImage.initrd" Linux image when you just
1982 change a file in your "initrd"). Also, a field-upgrade of the
1983 software is easier now.
1984
1985
1986Linux HOWTO:
1987============
1988
1989Porting Linux to U-Boot based systems:
1990---------------------------------------
1991
1992U-Boot cannot save you from doing all the necessary modifications to
1993configure the Linux device drivers for use with your target hardware
1994(no, we don't intend to provide a full virtual machine interface to
1995Linux :-).
1996
1997But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
1998
1999Just make sure your machine specific header file (for instance
2000include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2001Information structure as we define in include/u-boot.h, and make
2002sure that your definition of IMAP_ADDR uses the same value as your
2003U-Boot configuration in CFG_IMMR.
2004
2005
2006Configuring the Linux kernel:
2007-----------------------------
2008
2009No specific requirements for U-Boot. Make sure you have some root
2010device (initial ramdisk, NFS) for your target system.
2011
2012
2013Building a Linux Image:
2014-----------------------
2015
2016No specific requirements for U-Boot. There is no need to add a
2017"ramdisk.image.gz" file when building the kernel, even when you
2018intend to run it with initial ramdisk.
2019
2020Example:
2021
2022 make TQM850L_config
2023 make oldconfig
2024 make dep
2025 make zImage
2026
2027However, we don't use the 'zImage' (= 'arch/ppc/mbxboot/zvmlinux') we
2028build this way. The 'zImage' includes the old boot loader code which
2029we don't ned any more. Instead, we use the raw (compressed) Linux
2030kernel image in 'arch/ppc/coffboot/vmlinux.gz'.
2031
2032There is a special tool (in 'tools/mkimage') to encapsulate this
2033image with header information, CRC32 checksum etc. for use with
2034U-Boot:
2035
2036In the first form (with "-l" option) mkimage lists the information
2037contained in the header of an existing U-Boot image; this includes
2038checksum verification:
2039
2040 tools/mkimage -l image
2041 -l ==> list image header information
2042
2043The second form (with "-d" option) is used to build a U-Boot image
2044from a "data file" which is used as image payload:
2045
2046 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2047 -n name -d data_file image
2048 -A ==> set architecture to 'arch'
2049 -O ==> set operating system to 'os'
2050 -T ==> set image type to 'type'
2051 -C ==> set compression type 'comp'
2052 -a ==> set load address to 'addr' (hex)
2053 -e ==> set entry point to 'ep' (hex)
2054 -n ==> set image name to 'name'
2055 -d ==> use image data from 'datafile'
2056
2057Right now, all Linux kernels use the same load address (0x00000000),
2058but the entry point address depends on the kernel version:
2059
2060- 2.2.x kernels have the entry point at 0x0000000C,
2061- 2.3.x and 2.4.x kernels have the entry point at 0x00000000.
2062
2063So a typical call to build a U-Boot image would read:
2064
2065 -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \
2066 > -A ppc -O linux -T kernel -C gzip -a 00000000 -e 0000000C \
2067 > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz \
2068 > examples/image-2.2.13-initrd
2069 Image Name: 2.2.13 for initrd on TQM850L
2070 Created: Wed Jul 19 02:34:59 2000
2071 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2072 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2073 Load Address: 0x00000000
2074 Entry Point: 0x0000000c
2075
2076To verify the contents of the image (or check for corruption):
2077
2078 -> tools/mkimage -l examples/image-2.2.13-initrd
2079 Image Name: 2.2.13 for initrd on TQM850L
2080 Created: Wed Jul 19 02:34:59 2000
2081 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2082 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2083 Load Address: 0x00000000
2084 Entry Point: 0x0000000c
2085
2086NOTE: for embedded systems where boot time is critical you can trade
2087speed for memory and install an UNCOMPRESSED image instead: this
2088needs more space in Flash, but boots much faster since it does not
2089need to be uncompressed:
2090
2091 -> gunzip /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux.gz
2092 -> tools/mkimage -n '2.2.13 for initrd on TQM850L' \
2093 > -A ppc -O linux -T kernel -C none -a 00000000 -e 0000000C \
2094 > -d /opt/mpc8xx/src/linux-2.2.13/arch/ppc/coffboot/vmlinux \
2095 > examples/image-2.2.13-initrd-uncompressed
2096 Image Name: 2.2.13 for initrd on TQM850L
2097 Created: Wed Jul 19 02:34:59 2000
2098 Image Type: PowerPC Linux Kernel Image (uncompressed)
2099 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2100 Load Address: 0x00000000
2101 Entry Point: 0x0000000c
2102
2103
2104Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2105when your kernel is intended to use an initial ramdisk:
2106
2107 -> tools/mkimage -n 'Simple Ramdisk Image' \
2108 > -A ppc -O linux -T ramdisk -C gzip \
2109 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2110 Image Name: Simple Ramdisk Image
2111 Created: Wed Jan 12 14:01:50 2000
2112 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2113 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2114 Load Address: 0x00000000
2115 Entry Point: 0x00000000
2116
2117
2118Installing a Linux Image:
2119-------------------------
2120
2121To downloading a U-Boot image over the serial (console) interface,
2122you must convert the image to S-Record format:
2123
2124 objcopy -I binary -O srec examples/image examples/image.srec
2125
2126The 'objcopy' does not understand the information in the U-Boot
2127image header, so the resulting S-Record file will be relative to
2128address 0x00000000. To load it to a given address, you need to
2129specify the target address as 'offset' parameter with the 'loads'
2130command.
2131
2132Example: install the image to address 0x40100000 (which on the
2133TQM8xxL is in the first Flash bank):
2134
2135 => erase 40100000 401FFFFF
2136
2137 .......... done
2138 Erased 8 sectors
2139
2140 => loads 40100000
2141 ## Ready for S-Record download ...
2142 ~>examples/image.srec
2143 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2144 ...
2145 15989 15990 15991 15992
2146 [file transfer complete]
2147 [connected]
2148 ## Start Addr = 0x00000000
2149
2150
2151You can check the success of the download using the 'iminfo' command;
2152this includes a checksum verification so you can be sure no data
2153corruption happened:
2154
2155 => imi 40100000
2156
2157 ## Checking Image at 40100000 ...
2158 Image Name: 2.2.13 for initrd on TQM850L
2159 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2160 Data Size: 335725 Bytes = 327 kB = 0 MB
2161 Load Address: 00000000
2162 Entry Point: 0000000c
2163 Verifying Checksum ... OK
2164
2165
2166
2167Boot Linux:
2168-----------
2169
2170The "bootm" command is used to boot an application that is stored in
2171memory (RAM or Flash). In case of a Linux kernel image, the contents
2172of the "bootargs" environment variable is passed to the kernel as
2173parameters. You can check and modify this variable using the
2174"printenv" and "setenv" commands:
2175
2176
2177 => printenv bootargs
2178 bootargs=root=/dev/ram
2179
2180 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2181
2182 => printenv bootargs
2183 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2184
2185 => bootm 40020000
2186 ## Booting Linux kernel at 40020000 ...
2187 Image Name: 2.2.13 for NFS on TQM850L
2188 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2189 Data Size: 381681 Bytes = 372 kB = 0 MB
2190 Load Address: 00000000
2191 Entry Point: 0000000c
2192 Verifying Checksum ... OK
2193 Uncompressing Kernel Image ... OK
2194 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
2195 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2196 time_init: decrementer frequency = 187500000/60
2197 Calibrating delay loop... 49.77 BogoMIPS
2198 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2199 ...
2200
2201If you want to boot a Linux kernel with initial ram disk, you pass
2202the memory addreses of both the kernel and the initrd image (PPBCOOT
2203format!) to the "bootm" command:
2204
2205 => imi 40100000 40200000
2206
2207 ## Checking Image at 40100000 ...
2208 Image Name: 2.2.13 for initrd on TQM850L
2209 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2210 Data Size: 335725 Bytes = 327 kB = 0 MB
2211 Load Address: 00000000
2212 Entry Point: 0000000c
2213 Verifying Checksum ... OK
2214
2215 ## Checking Image at 40200000 ...
2216 Image Name: Simple Ramdisk Image
2217 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2218 Data Size: 566530 Bytes = 553 kB = 0 MB
2219 Load Address: 00000000
2220 Entry Point: 00000000
2221 Verifying Checksum ... OK
2222
2223 => bootm 40100000 40200000
2224 ## Booting Linux kernel at 40100000 ...
2225 Image Name: 2.2.13 for initrd on TQM850L
2226 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2227 Data Size: 335725 Bytes = 327 kB = 0 MB
2228 Load Address: 00000000
2229 Entry Point: 0000000c
2230 Verifying Checksum ... OK
2231 Uncompressing Kernel Image ... OK
2232 ## Loading RAMDisk Image at 40200000 ...
2233 Image Name: Simple Ramdisk Image
2234 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2235 Data Size: 566530 Bytes = 553 kB = 0 MB
2236 Load Address: 00000000
2237 Entry Point: 00000000
2238 Verifying Checksum ... OK
2239 Loading Ramdisk ... OK
2240 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
2241 Boot arguments: root=/dev/ram
2242 time_init: decrementer frequency = 187500000/60
2243 Calibrating delay loop... 49.77 BogoMIPS
2244 ...
2245 RAMDISK: Compressed image found at block 0
2246 VFS: Mounted root (ext2 filesystem).
2247
2248 bash#
2249
2250
2251Standalone HOWTO:
2252=================
2253
2254One of the features of U-Boot is that you can dynamically load and
2255run "standalone" applications, which can use some resources of
2256U-Boot like console I/O functions or interrupt services.
2257
2258Two simple examples are included with the sources:
2259
2260"Hello World" Demo:
2261-------------------
2262
2263'examples/hello_world.c' contains a small "Hello World" Demo
2264application; it is automatically compiled when you build U-Boot.
2265It's configured to run at address 0x00040004, so you can play with it
2266like that:
2267
2268 => loads
2269 ## Ready for S-Record download ...
2270 ~>examples/hello_world.srec
2271 1 2 3 4 5 6 7 8 9 10 11 ...
2272 [file transfer complete]
2273 [connected]
2274 ## Start Addr = 0x00040004
2275
2276 => go 40004 Hello World! This is a test.
2277 ## Starting application at 0x00040004 ...
2278 Hello World
2279 argc = 7
2280 argv[0] = "40004"
2281 argv[1] = "Hello"
2282 argv[2] = "World!"
2283 argv[3] = "This"
2284 argv[4] = "is"
2285 argv[5] = "a"
2286 argv[6] = "test."
2287 argv[7] = "<NULL>"
2288 Hit any key to exit ...
2289
2290 ## Application terminated, rc = 0x0
2291
2292Another example, which demonstrates how to register a CPM interrupt
2293handler with the U-Boot code, can be found in 'examples/timer.c'.
2294Here, a CPM timer is set up to generate an interrupt every second.
2295The interrupt service routine is trivial, just printing a '.'
2296character, but this is just a demo program. The application can be
2297controlled by the following keys:
2298
2299 ? - print current values og the CPM Timer registers
2300 b - enable interrupts and start timer
2301 e - stop timer and disable interrupts
2302 q - quit application
2303
2304 => loads
2305 ## Ready for S-Record download ...
2306 ~>examples/timer.srec
2307 1 2 3 4 5 6 7 8 9 10 11 ...
2308 [file transfer complete]
2309 [connected]
2310 ## Start Addr = 0x00040004
2311
2312 => go 40004
2313 ## Starting application at 0x00040004 ...
2314 TIMERS=0xfff00980
2315 Using timer 1
2316 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2317
2318Hit 'b':
2319 [q, b, e, ?] Set interval 1000000 us
2320 Enabling timer
2321Hit '?':
2322 [q, b, e, ?] ........
2323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2324Hit '?':
2325 [q, b, e, ?] .
2326 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2327Hit '?':
2328 [q, b, e, ?] .
2329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2330Hit '?':
2331 [q, b, e, ?] .
2332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2333Hit 'e':
2334 [q, b, e, ?] ...Stopping timer
2335Hit 'q':
2336 [q, b, e, ?] ## Application terminated, rc = 0x0
2337
2338
2339NetBSD Notes:
2340=============
2341
2342Starting at version 0.9.2, U-Boot supports NetBSD both as host
2343(build U-Boot) and target system (boots NetBSD/mpc8xx).
2344
2345Building requires a cross environment; it is known to work on
2346NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2347need gmake since the Makefiles are not compatible with BSD make).
2348Note that the cross-powerpc package does not install include files;
2349attempting to build U-Boot will fail because <machine/ansi.h> is
2350missing. This file has to be installed and patched manually:
2351
2352 # cd /usr/pkg/cross/powerpc-netbsd/include
2353 # mkdir powerpc
2354 # ln -s powerpc machine
2355 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2356 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2357
2358Native builds *don't* work due to incompatibilities between native
2359and U-Boot include files.
2360
2361Booting assumes that (the first part of) the image booted is a
2362stage-2 loader which in turn loads and then invokes the kernel
2363proper. Loader sources will eventually appear in the NetBSD source
2364tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2365meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2366details.
2367
2368
2369Implementation Internals:
2370=========================
2371
2372The following is not intended to be a complete description of every
2373implementation detail. However, it should help to understand the
2374inner workings of U-Boot and make it easier to port it to custom
2375hardware.
2376
2377
2378Initial Stack, Global Data:
2379---------------------------
2380
2381The implementation of U-Boot is complicated by the fact that U-Boot
2382starts running out of ROM (flash memory), usually without access to
2383system RAM (because the memory controller is not initialized yet).
2384This means that we don't have writable Data or BSS segments, and BSS
2385is not initialized as zero. To be able to get a C environment working
2386at all, we have to allocate at least a minimal stack. Implementation
2387options for this are defined and restricted by the CPU used: Some CPU
2388models provide on-chip memory (like the IMMR area on MPC8xx and
2389MPC826x processors), on others (parts of) the data cache can be
2390locked as (mis-) used as memory, etc.
2391
2392It is essential to remember this, since it has some impact on the C
2393code for the initialization procedures:
2394
2395* Initialized global data (data segment) is read-only. Do not attempt
2396 to write it.
2397
2398* Do not use any unitialized global data (or implicitely initialized
2399 as zero data - BSS segment) at all - this is undefined, initiali-
2400 zation is performed later (when relocationg to RAM).
2401
2402* Stack space is very limited. Avoid big data buffers or things like
2403 that.
2404
2405Having only the stack as writable memory limits means we cannot use
2406normal global data to share information beween the code. But it
2407turned out that the implementation of U-Boot can be greatly
2408simplified by making a global data structure (gd_t) available to all
2409functions. We could pass a pointer to this data as argument to _all_
2410functions, but this would bloat the code. Instead we use a feature of
2411the GCC compiler (Global Register Variables) to share the data: we
2412place a pointer (gd) to the global data into a register which we
2413reserve for this purpose.
2414
2415When chosing a register for such a purpose we are restricted by the
2416relevant (E)ABI specifications for the current architecture, and by
2417GCC's implementation.
2418
2419For PowerPC, the following registers have specific use:
2420 R1: stack pointer
2421 R2: TOC pointer
2422 R3-R4: parameter passing and return values
2423 R5-R10: parameter passing
2424 R13: small data area pointer
2425 R30: GOT pointer
2426 R31: frame pointer
2427
2428 (U-Boot also uses R14 as internal GOT pointer.)
2429
2430 ==> U-Boot will use R29 to hold a pointer to the global data
2431
2432 Note: on PPC, we could use a static initializer (since the
2433 address of the global data structure is known at compile time),
2434 but it turned out that reserving a register results in somewhat
2435 smaller code - although the code savings are not that big (on
2436 average for all boards 752 bytes for the whole U-Boot image,
2437 624 text + 127 data).
2438
2439On ARM, the following registers are used:
2440
2441 R0: function argument word/integer result
2442 R1-R3: function argument word
2443 R9: GOT pointer
2444 R10: stack limit (used only if stack checking if enabled)
2445 R11: argument (frame) pointer
2446 R12: temporary workspace
2447 R13: stack pointer
2448 R14: link register
2449 R15: program counter
2450
2451 ==> U-Boot will use R8 to hold a pointer to the global data
2452
2453
2454
2455Memory Management:
2456------------------
2457
2458U-Boot runs in system state and uses physical addresses, i.e. the
2459MMU is not used either for address mapping nor for memory protection.
2460
2461The available memory is mapped to fixed addresses using the memory
2462controller. In this process, a contiguous block is formed for each
2463memory type (Flash, SDRAM, SRAM), even when it consists of several
2464physical memory banks.
2465
2466U-Boot is installed in the first 128 kB of the first Flash bank (on
2467TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2468booting and sizing and initializing DRAM, the code relocates itself
2469to the upper end of DRAM. Immediately below the U-Boot code some
2470memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2471configuration setting]. Below that, a structure with global Board
2472Info data is placed, followed by the stack (growing downward).
2473
2474Additionally, some exception handler code is copied to the low 8 kB
2475of DRAM (0x00000000 ... 0x00001FFF).
2476
2477So a typical memory configuration with 16 MB of DRAM could look like
2478this:
2479
2480 0x0000 0000 Exception Vector code
2481 :
2482 0x0000 1FFF
2483 0x0000 2000 Free for Application Use
2484 :
2485 :
2486
2487 :
2488 :
2489 0x00FB FF20 Monitor Stack (Growing downward)
2490 0x00FB FFAC Board Info Data and permanent copy of global data
2491 0x00FC 0000 Malloc Arena
2492 :
2493 0x00FD FFFF
2494 0x00FE 0000 RAM Copy of Monitor Code
2495 ... eventually: LCD or video framebuffer
2496 ... eventually: pRAM (Protected RAM - unchanged by reset)
2497 0x00FF FFFF [End of RAM]
2498
2499
2500System Initialization:
2501----------------------
2502
2503In the reset configuration, U-Boot starts at the reset entry point
2504(on most PowerPC systens at address 0x00000100). Because of the reset
2505configuration for CS0# this is a mirror of the onboard Flash memory.
2506To be able to re-map memory U-Boot then jumps to it's link address.
2507To be able to implement the initialization code in C, a (small!)
2508initial stack is set up in the internal Dual Ported RAM (in case CPUs
2509which provide such a feature like MPC8xx or MPC8260), or in a locked
2510part of the data cache. After that, U-Boot initializes the CPU core,
2511the caches and the SIU.
2512
2513Next, all (potentially) available memory banks are mapped using a
2514preliminary mapping. For example, we put them on 512 MB boundaries
2515(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2516on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2517programmed for SDRAM access. Using the temporary configuration, a
2518simple memory test is run that determines the size of the SDRAM
2519banks.
2520
2521When there is more than one SDRAM bank, and the banks are of
2522different size, the larger is mapped first. For equal size, the first
2523bank (CS2#) is mapped first. The first mapping is always for address
25240x00000000, with any additional banks following immediately to create
2525contiguous memory starting from 0.
2526
2527Then, the monitor installs itself at the upper end of the SDRAM area
2528and allocates memory for use by malloc() and for the global Board
2529Info data; also, the exception vector code is copied to the low RAM
2530pages, and the final stack is set up.
2531
2532Only after this relocation will you have a "normal" C environment;
2533until that you are restricted in several ways, mostly because you are
2534running from ROM, and because the code will have to be relocated to a
2535new address in RAM.
2536
2537
2538U-Boot Porting Guide:
2539----------------------
2540
2541[Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2542list, Octover 2002]
2543
2544
2545int main (int argc, char *argv[])
2546{
2547 sighandler_t no_more_time;
2548
2549 signal (SIGALRM, no_more_time);
2550 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2551
2552 if (available_money > available_manpower) {
2553 pay consultant to port U-Boot;
2554 return 0;
2555 }
2556
2557 Download latest U-Boot source;
2558
2559 if (clueless) {
2560 email ("Hi, I am new to U-Boot, how do I get started?");
2561 }
2562
2563 while (learning) {
2564 Read the README file in the top level directory;
2565 Read http://www.denx.de/re/DPLG.html
2566 Read the source, Luke;
2567 }
2568
2569 if (available_money > toLocalCurrency ($2500)) {
2570 Buy a BDI2000;
2571 } else {
2572 Add a lot of aggravation and time;
2573 }
2574
2575 Create your own board support subdirectory;
2576
2577 while (!running) {
2578 do {
2579 Add / modify source code;
2580 } until (compiles);
2581 Debug;
2582 if (clueless)
2583 email ("Hi, I am having problems...");
2584 }
2585 Send patch file to Wolfgang;
2586
2587 return 0;
2588}
2589
2590void no_more_time (int sig)
2591{
2592 hire_a_guru();
2593}
2594
2595
2596
2597Coding Standards:
2598-----------------
2599
2600All contributions to U-Boot should conform to the Linux kernel
2601coding style; see the file "Documentation/CodingStyle" in your Linux
2602kernel source directory.
2603
2604Please note that U-Boot is implemented in C (and to some small parts
2605in Assembler); no C++ is used, so please do not use C++ style
2606comments (//) in your code.
2607
2608Submissions which do not conform to the standards may be returned
2609with a request to reformat the changes.
2610
2611
2612Submitting Patches:
2613-------------------
2614
2615Since the number of patches for U-Boot is growing, we need to
2616establish some rules. Submissions which do not conform to these rules
2617may be rejected, even when they contain important and valuable stuff.
2618
2619
2620When you send a patch, please include the following information with
2621it:
2622
2623* For bug fixes: a description of the bug and how your patch fixes
2624 this bug. Please try to include a way of demonstrating that the
2625 patch actually fixes something.
2626
2627* For new features: a description of the feature and your
2628 implementation.
2629
2630* A CHANGELOG entry as plaintext (separate from the patch)
2631
2632* For major contributions, your entry to the CREDITS file
2633
2634* When you add support for a new board, don't forget to add this
2635 board to the MAKEALL script, too.
2636
2637* If your patch adds new configuration options, don't forget to
2638 document these in the README file.
2639
2640* The patch itself. If you are accessing the CVS repository use "cvs
2641 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2642 version of diff does not support these options, then get the latest
2643 version of GNU diff.
2644
2645 We accept patches as plain text, MIME attachments or as uuencoded
2646 gzipped text.
2647
2648Notes:
2649
2650* Before sending the patch, run the MAKEALL script on your patched
2651 source tree and make sure that no errors or warnings are reported
2652 for any of the boards.
2653
2654* Keep your modifications to the necessary minimum: A patch
2655 containing several unrelated changes or arbitrary reformats will be
2656 returned with a request to re-formatting / split it.
2657
2658* If you modify existing code, make sure that your new code does not
2659 add to the memory footprint of the code ;-) Small is beautiful!
2660 When adding new features, these should compile conditionally only
2661 (using #ifdef), and the resulting code with the new feature
2662 disabled must not need more memory than the old code without your
2663 modification.