2 # (C) Copyright 2000 - 2002
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
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.
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.
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,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC and ARM processors, which can be
29 installed in a boot ROM and used to initialize and test the hardware
30 or to download and run application code.
32 The development of U-Boot is closely related to Linux: some parts of
33 the source code originate in the Linux source tree, we have some
34 header files in common, and special provision has been made to
35 support booting of Linux images.
37 Some attention has been paid to make this software easily
38 configurable and extendable. For instance, all monitor commands are
39 implemented with the same call interface, so that it's very easy to
40 add new commands. Also, instead of permanently adding rarely used
41 code (for instance hardware test utilities) to the monitor, you can
42 load and run it dynamically.
48 In general, all boards for which a configuration option exists in the
49 Makefile have been tested to some extent and can be considered
50 "working". In fact, many of them are used in production systems.
52 In case of problems see the CHANGELOG and CREDITS files to find out
53 who contributed the specific port.
59 In case you have questions about, problems with or contributions for
60 U-Boot you should send a message to the U-Boot mailing list at
61 <u-boot-users@lists.sourceforge.net>. There is also an archive of
62 previous traffic on the mailing list - please search the archive
63 before asking FAQ's. Please see
64 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
70 - start from 8xxrom sources
71 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
73 - make it easier to add custom boards
74 - make it possible to add other [PowerPC] CPUs
75 - extend functions, especially:
76 * Provide extended interface to Linux boot loader
79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80 - create ARMBoot project (http://sourceforge.net/projects/armboot)
81 - add other CPU families (starting with ARM)
82 - create U-Boot project (http://sourceforge.net/projects/u-boot)
88 The "official" name of this project is "Das U-Boot". The spelling
89 "U-Boot" shall be used in all written text (documentation, comments
90 in source files etc.). Example:
92 This is the README file for the U-Boot project.
94 File names etc. shall be based on the string "u-boot". Examples:
96 include/asm-ppc/u-boot.h
98 #include <asm/u-boot.h>
100 Variable names, preprocessor constants etc. shall be either based on
101 the string "u_boot" or on "U_BOOT". Example:
103 U_BOOT_VERSION u_boot_logo
104 IH_OS_U_BOOT u_boot_hush_start
110 U-Boot uses a 3 level version number containing a version, a
111 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112 sub-version "34", and patchlevel "4".
114 The patchlevel is used to indicate certain stages of development
115 between released versions, i. e. officially released versions of
116 U-Boot will always have a patchlevel of "0".
122 - board Board dependent files
123 - common Misc architecture independent functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Commonly used device drivers
128 - dtt Digital Thermometer and Thermostat drivers
129 - examples Example code for standalone applications, etc.
130 - include Header Files
131 - disk Harddisk interface code
132 - net Networking code
133 - ppc Files generic to PowerPC architecture
134 - post Power On Self Test
135 - post/arch Symlink to architecture specific Power On Self Test
136 - post/arch-ppc PowerPC architecture specific Power On Self Test
137 - post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138 - post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139 - rtc Real Time Clock drivers
140 - tools Tools to build S-Record or U-Boot images, etc.
142 - cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
143 - cpu/arm925t Files specific to ARM 925 CPUs
144 - cpu/arm926ejs Files specific to ARM 926 CPUs
145 - cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
146 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
147 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
148 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
149 - cpu/ppc4xx Files specific to IBM 4xx CPUs
152 - board/LEOX/ Files specific to boards manufactured by The LEOX team
153 - board/LEOX/elpt860 Files specific to ELPT860 boards
155 Files specific to RPXClassic boards
156 - board/RPXlite Files specific to RPXlite boards
157 - board/at91rm9200dk Files specific to AT91RM9200DK boards
158 - board/c2mon Files specific to c2mon boards
159 - board/cmi Files specific to cmi boards
160 - board/cogent Files specific to Cogent boards
161 (need further configuration)
162 Files specific to CPCIISER4 boards
163 - board/cpu86 Files specific to CPU86 boards
164 - board/cray/ Files specific to boards manufactured by Cray
165 - board/cray/L1 Files specific to L1 boards
166 - board/cu824 Files specific to CU824 boards
167 - board/ebony Files specific to IBM Ebony board
168 - board/eric Files specific to ERIC boards
169 - board/esd/ Files specific to boards manufactured by ESD
170 - board/esd/adciop Files specific to ADCIOP boards
171 - board/esd/ar405 Files specific to AR405 boards
172 - board/esd/canbt Files specific to CANBT boards
173 - board/esd/cpci405 Files specific to CPCI405 boards
174 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
175 - board/esd/common Common files for ESD boards
176 - board/esd/dasa_sim Files specific to DASA_SIM boards
177 - board/esd/du405 Files specific to DU405 boards
178 - board/esd/ocrtc Files specific to OCRTC boards
179 - board/esd/pci405 Files specific to PCI405 boards
181 Files specific to ESTEEM192E boards
182 - board/etx094 Files specific to ETX_094 boards
184 Files specific to EVB64260 boards
185 - board/fads Files specific to FADS boards
186 - board/flagadm Files specific to FLAGADM boards
187 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
188 - board/genietv Files specific to GENIETV boards
189 - board/gth Files specific to GTH boards
190 - board/hermes Files specific to HERMES boards
191 - board/hymod Files specific to HYMOD boards
192 - board/icu862 Files specific to ICU862 boards
193 - board/ip860 Files specific to IP860 boards
195 Files specific to Interphase4539 boards
196 - board/ivm Files specific to IVMS8/IVML24 boards
197 - board/lantec Files specific to LANTEC boards
198 - board/lwmon Files specific to LWMON boards
199 - board/mbx8xx Files specific to MBX boards
201 Files specific to MPC8260ADS and PQ2FADS-ZU boards
202 - board/mpl/ Files specific to boards manufactured by MPL
203 - board/mpl/common Common files for MPL boards
204 - board/mpl/pip405 Files specific to PIP405 boards
205 - board/mpl/mip405 Files specific to MIP405 boards
206 - board/mpl/vcma9 Files specific to VCMA9 boards
207 - board/musenki Files specific to MUSEKNI boards
208 - board/mvs1 Files specific to MVS1 boards
209 - board/nx823 Files specific to NX823 boards
210 - board/oxc Files specific to OXC boards
212 Files specific to OMAP 1510 Innovator boards
214 Files specific to OMAP 1610 Innovator boards
215 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
216 - board/pm826 Files specific to PM826 boards
218 Files specific to PPMC8260 boards
220 Files specific to RPXsuper boards
222 Files specific to RSDproto boards
224 Files specific to Sandpoint boards
225 - board/sbc8260 Files specific to SBC8260 boards
226 - board/sacsng Files specific to SACSng boards
227 - board/siemens Files specific to boards manufactured by Siemens AG
228 - board/siemens/CCM Files specific to CCM boards
229 - board/siemens/IAD210 Files specific to IAD210 boards
230 - board/siemens/SCM Files specific to SCM boards
231 - board/siemens/pcu_e Files specific to PCU_E boards
232 - board/sixnet Files specific to SIXNET boards
233 - board/spd8xx Files specific to SPD8xxTS boards
234 - board/tqm8260 Files specific to TQM8260 boards
235 - board/tqm8xx Files specific to TQM8xxL boards
236 - board/w7o Files specific to W7O boards
238 Files specific to Walnut405 boards
239 - board/westel/ Files specific to boards manufactured by Westel Wireless
240 - board/westel/amx860 Files specific to AMX860 boards
241 - board/utx8245 Files specific to UTX8245 boards
243 Software Configuration:
244 =======================
246 Configuration is usually done using C preprocessor defines; the
247 rationale behind that is to avoid dead code whenever possible.
249 There are two classes of configuration variables:
251 * Configuration _OPTIONS_:
252 These are selectable by the user and have names beginning with
255 * Configuration _SETTINGS_:
256 These depend on the hardware etc. and should not be meddled with if
257 you don't know what you're doing; they have names beginning with
260 Later we will add a configuration tool - probably similar to or even
261 identical to what's used for the Linux kernel. Right now, we have to
262 do the configuration by hand, which means creating some symbolic
263 links and editing some configuration files. We use the TQM8xxL boards
267 Selection of Processor Architecture and Board Type:
268 ---------------------------------------------------
270 For all supported boards there are ready-to-use default
271 configurations available; just type "make <board_name>_config".
273 Example: For a TQM823L module type:
278 For the Cogent platform, you need to specify the cpu type as well;
279 e.g. "make cogent_mpc8xx_config". And also configure the cogent
280 directory according to the instructions in cogent/README.
283 Configuration Options:
284 ----------------------
286 Configuration depends on the combination of board and CPU type; all
287 such information is kept in a configuration file
288 "include/configs/<board_name>.h".
290 Example: For a TQM823L module, all configuration settings are in
291 "include/configs/TQM823L.h".
294 Many of the options are named exactly as the corresponding Linux
295 kernel configuration options. The intention is to make it easier to
296 build a config tool - later.
299 The following options need to be configured:
301 - CPU Type: Define exactly one of
305 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
307 or CONFIG_MPC824X, CONFIG_MPC8260
322 - Board Type: Define exactly one of
324 PowerPC based boards:
325 ---------------------
327 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
328 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
329 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
330 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
331 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
332 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
333 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
334 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
335 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
336 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
337 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
338 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
339 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
340 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
341 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
342 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
343 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
344 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
345 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
346 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
347 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
348 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
349 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
350 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
351 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
352 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
353 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
354 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
355 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
356 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
357 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
358 CONFIG_NETVIA, CONFIG_RBC823
363 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
364 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
365 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610
366 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
367 CONFIG_TRAB, CONFIG_VCMA9, CONFIG_AT91RM9200DK
370 - CPU Module Type: (if CONFIG_COGENT is defined)
371 Define exactly one of
373 --- FIXME --- not tested yet:
374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375 CONFIG_CMA287_23, CONFIG_CMA287_50
377 - Motherboard Type: (if CONFIG_COGENT is defined)
378 Define exactly one of
379 CONFIG_CMA101, CONFIG_CMA102
381 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382 Define one or more of
385 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386 Define one or more of
387 CONFIG_LCD_HEARTBEAT - update a character position on
388 the lcd display every second with
391 - Board flavour: (if CONFIG_MPC8260ADS is defined)
394 CFG_8260ADS - original MPC8260ADS
395 CFG_8266ADS - MPC8266ADS (untested)
396 CFG_PQ2FADS - PQ2FADS-ZU
399 - MPC824X Family Member (if CONFIG_MPC824X is defined)
400 Define exactly one of
401 CONFIG_MPC8240, CONFIG_MPC8245
403 - 8xx CPU Options: (if using an 8xx cpu)
404 Define one or more of
405 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
406 no 32KHz reference PIT/RTC clock
411 U-Boot stores all clock information in Hz
412 internally. For binary compatibility with older Linux
413 kernels (which expect the clocks passed in the
414 bd_info data to be in MHz) the environment variable
415 "clocks_in_mhz" can be defined so that U-Boot
416 converts clock data to MHZ before passing it to the
419 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
420 "clocks_in_mhz=1" is automatically included in the
424 Depending on board, define exactly one serial port
425 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
426 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
427 console by defining CONFIG_8xx_CONS_NONE
429 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
430 port routines must be defined elsewhere
431 (i.e. serial_init(), serial_getc(), ...)
434 Enables console device for a color framebuffer. Needs following
435 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
436 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
438 VIDEO_HW_RECTFILL graphic chip supports
441 VIDEO_HW_BITBLT graphic chip supports
442 bit-blit (cf. smiLynxEM)
443 VIDEO_VISIBLE_COLS visible pixel columns
445 VIDEO_VISIBLE_ROWS visible pixel rows
446 VIDEO_PIXEL_SIZE bytes per pixel
447 VIDEO_DATA_FORMAT graphic data format
448 (0-5, cf. cfb_console.c)
449 VIDEO_FB_ADRS framebuffer address
450 VIDEO_KBD_INIT_FCT keyboard int fct
451 (i.e. i8042_kbd_init())
452 VIDEO_TSTC_FCT test char fct
454 VIDEO_GETC_FCT get char fct
456 CONFIG_CONSOLE_CURSOR cursor drawing on/off
457 (requires blink timer
459 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
460 CONFIG_CONSOLE_TIME display time/date info in
462 (requires CFG_CMD_DATE)
463 CONFIG_VIDEO_LOGO display Linux logo in
465 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
466 linux_logo.h for logo.
467 Requires CONFIG_VIDEO_LOGO
468 CONFIG_CONSOLE_EXTRA_INFO
469 addional board info beside
472 When CONFIG_CFB_CONSOLE is defined, video console is
473 default i/o. Serial console can be forced with
474 environment 'console=serial'.
477 CONFIG_BAUDRATE - in bps
478 Select one of the baudrates listed in
479 CFG_BAUDRATE_TABLE, see below.
481 - Interrupt driven serial port input:
482 CONFIG_SERIAL_SOFTWARE_FIFO
485 Use an interrupt handler for receiving data on the
486 serial port. It also enables using hardware handshake
487 (RTS/CTS) and UART's built-in FIFO. Set the number of
488 bytes the interrupt driven input buffer should have.
490 Set to 0 to disable this feature (this is the default).
491 This will also disable hardware handshake.
493 - Console UART Number:
497 If defined internal UART1 (and not UART0) is used
498 as default U-Boot console.
500 - Boot Delay: CONFIG_BOOTDELAY - in seconds
501 Delay before automatically booting the default image;
502 set to -1 to disable autoboot.
504 See doc/README.autoboot for these options that
505 work with CONFIG_BOOTDELAY. None are required.
506 CONFIG_BOOT_RETRY_TIME
507 CONFIG_BOOT_RETRY_MIN
508 CONFIG_AUTOBOOT_KEYED
509 CONFIG_AUTOBOOT_PROMPT
510 CONFIG_AUTOBOOT_DELAY_STR
511 CONFIG_AUTOBOOT_STOP_STR
512 CONFIG_AUTOBOOT_DELAY_STR2
513 CONFIG_AUTOBOOT_STOP_STR2
514 CONFIG_ZERO_BOOTDELAY_CHECK
515 CONFIG_RESET_TO_RETRY
519 Only needed when CONFIG_BOOTDELAY is enabled;
520 define a command string that is automatically executed
521 when no character is read on the console interface
522 within "Boot Delay" after reset.
525 This can be used to pass arguments to the bootm
526 command. The value of CONFIG_BOOTARGS goes into the
527 environment value "bootargs".
529 CONFIG_RAMBOOT and CONFIG_NFSBOOT
530 The value of these goes into the environment as
531 "ramboot" and "nfsboot" respectively, and can be used
532 as a convenience, when switching between booting from
538 When this option is #defined, the existence of the
539 environment variable "preboot" will be checked
540 immediately before starting the CONFIG_BOOTDELAY
541 countdown and/or running the auto-boot command resp.
542 entering interactive mode.
544 This feature is especially useful when "preboot" is
545 automatically generated or modified. For an example
546 see the LWMON board specific code: here "preboot" is
547 modified when the user holds down a certain
548 combination of keys on the (special) keyboard when
551 - Serial Download Echo Mode:
553 If defined to 1, all characters received during a
554 serial download (using the "loads" command) are
555 echoed back. This might be needed by some terminal
556 emulations (like "cu"), but may as well just take
557 time on others. This setting #define's the initial
558 value of the "loads_echo" environment variable.
560 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
562 Select one of the baudrates listed in
563 CFG_BAUDRATE_TABLE, see below.
567 Most monitor functions can be selected (or
568 de-selected) by adjusting the definition of
569 CONFIG_COMMANDS; to select individual functions,
570 #define CONFIG_COMMANDS by "OR"ing any of the
573 #define enables commands:
574 -------------------------
575 CFG_CMD_ASKENV * ask for env variable
576 CFG_CMD_AUTOSCRIPT Autoscript Support
578 CFG_CMD_BEDBUG Include BedBug Debugger
579 CFG_CMD_BMP * BMP support
581 CFG_CMD_CACHE icache, dcache
582 CFG_CMD_CONSOLE coninfo
583 CFG_CMD_DATE * support for RTC, date/time...
584 CFG_CMD_DHCP DHCP support
585 CFG_CMD_DIAG * Diagnostics
586 CFG_CMD_DOC * Disk-On-Chip Support
587 CFG_CMD_DTT Digital Therm and Thermostat
588 CFG_CMD_ECHO * echo arguments
589 CFG_CMD_EEPROM * EEPROM read/write support
590 CFG_CMD_ELF bootelf, bootvx
592 CFG_CMD_FDC * Floppy Disk Support
593 CFG_CMD_FAT FAT partition support
594 CFG_CMD_FDOS * Dos diskette Support
595 CFG_CMD_FLASH flinfo, erase, protect
596 CFG_CMD_FPGA FPGA device initialization support
597 CFG_CMD_HWFLOW * RTS/CTS hw flow control
598 CFG_CMD_I2C * I2C serial bus support
599 CFG_CMD_IDE * IDE harddisk support
601 CFG_CMD_IMLS List all found images
602 CFG_CMD_IMMAP * IMMR dump support
603 CFG_CMD_IRQ * irqinfo
604 CFG_CMD_JFFS2 * JFFS2 Support
608 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
610 CFG_CMD_MISC Misc functions like sleep etc
611 CFG_CMD_MMC MMC memory mapped support
612 CFG_CMD_MII MII utility commands
613 CFG_CMD_NAND * NAND support
614 CFG_CMD_NET bootp, tftpboot, rarpboot
615 CFG_CMD_PCI * pciinfo
616 CFG_CMD_PCMCIA * PCMCIA support
617 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
618 CFG_CMD_PORTIO Port I/O
619 CFG_CMD_REGINFO * Register dump
620 CFG_CMD_RUN run command in env variable
621 CFG_CMD_SAVES save S record dump
622 CFG_CMD_SCSI * SCSI Support
623 CFG_CMD_SDRAM * print SDRAM configuration information
624 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
625 CFG_CMD_SPI * SPI serial bus support
626 CFG_CMD_USB * USB support
627 CFG_CMD_VFD * VFD support (TRAB)
628 CFG_CMD_BSP * Board SPecific functions
629 -----------------------------------------------
632 CFG_CMD_DFL Default configuration; at the moment
633 this is includes all commands, except
634 the ones marked with "*" in the list
637 If you don't define CONFIG_COMMANDS it defaults to
638 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
639 override the default settings in the respective
642 EXAMPLE: If you want all functions except of network
643 support you can write:
645 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
648 Note: Don't enable the "icache" and "dcache" commands
649 (configuration option CFG_CMD_CACHE) unless you know
650 what you (and your U-Boot users) are doing. Data
651 cache cannot be enabled on systems like the 8xx or
652 8260 (where accesses to the IMMR region must be
653 uncached), and it cannot be disabled on all other
654 systems where we (mis-) use the data cache to hold an
655 initial stack and some data.
658 XXX - this list needs to get updated!
662 If this variable is defined, it enables watchdog
663 support. There must be support in the platform specific
664 code for a watchdog. For the 8xx and 8260 CPUs, the
665 SIU Watchdog feature is enabled in the SYPCR
669 CONFIG_VERSION_VARIABLE
670 If this variable is defined, an environment variable
671 named "ver" is created by U-Boot showing the U-Boot
672 version as printed by the "version" command.
673 This variable is readonly.
677 When CFG_CMD_DATE is selected, the type of the RTC
678 has to be selected, too. Define exactly one of the
681 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
682 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
683 CONFIG_RTC_MC146818 - use MC146818 RTC
684 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
685 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
686 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
687 CONFIG_RTC_DS164x - use Dallas DS164x RTC
689 Note that if the RTC uses I2C, then the I2C interface
690 must also be configured. See I2C Support, below.
694 When CONFIG_TIMESTAMP is selected, the timestamp
695 (date and time) of an image is printed by image
696 commands like bootm or iminfo. This option is
697 automatically enabled when you select CFG_CMD_DATE .
700 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
701 and/or CONFIG_ISO_PARTITION
703 If IDE or SCSI support is enabled (CFG_CMD_IDE or
704 CFG_CMD_SCSI) you must configure support for at least
705 one partition type as well.
708 CONFIG_IDE_RESET_ROUTINE
710 Set this to define that instead of a reset Pin, the
711 routine ide_set_reset(int idereset) will be used.
716 Set this to enable ATAPI support.
719 At the moment only there is only support for the
720 SYM53C8XX SCSI controller; define
721 CONFIG_SCSI_SYM53C8XX to enable it.
723 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
724 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
725 CFG_SCSI_MAX_LUN] can be adjusted to define the
726 maximum numbers of LUNs, SCSI ID's and target
728 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
730 - NETWORK Support (PCI):
732 Support for Intel 8254x gigabit chips.
735 Support for Intel 82557/82559/82559ER chips.
736 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
737 write routine for first time initialisation.
740 Support for Digital 2114x chips.
741 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
742 modem chip initialisation (KS8761/QS6611).
745 Support for National dp83815 chips.
748 Support for National dp8382[01] gigabit chips.
750 - NETWORK Support (other):
752 CONFIG_DRIVER_LAN91C96
753 Support for SMSC's LAN91C96 chips.
756 Define this to hold the physical address
757 of the LAN91C96's I/O space
759 CONFIG_LAN91C96_USE_32_BIT
760 Define this to enable 32 bit addressing
763 At the moment only the UHCI host controller is
764 supported (PIP405, MIP405); define
765 CONFIG_USB_UHCI to enable it.
766 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
767 end define CONFIG_USB_STORAGE to enable the USB
770 Supported are USB Keyboards and USB Floppy drives
774 The MMC controller on the Intel PXA is supported. To
775 enable this define CONFIG_MMC. The MMC can be
776 accessed from the boot prompt by mapping the device
777 to physical memory similar to flash. Command line is
778 enabled with CFG_CMD_MMC. The MMC driver also works with
779 the FAT fs. This is enabled with CFG_CMD_FAT.
784 Define this to enable standard (PC-Style) keyboard
788 Standard PC keyboard driver with US (is default) and
789 GERMAN key layout (switch via environment 'keymap=de') support.
790 Export function i8042_kbd_init, i8042_tstc and i8042_getc
791 for cfb_console. Supports cursor blinking.
796 Define this to enable video support (for output to
801 Enable Chips & Technologies 69000 Video chip
803 CONFIG_VIDEO_SMI_LYNXEM
804 Enable Silicon Motion SMI 712/710/810 Video chip
805 Videomode are selected via environment 'videomode' with
806 standard LiLo mode numbers.
807 Following modes are supported (* is default):
809 800x600 1024x768 1280x1024
810 256 (8bit) 303* 305 307
811 65536 (16bit) 314 317 31a
812 16,7 Mill (24bit) 315 318 31b
813 (i.e. setenv videomode 317; saveenv; reset;)
815 CONFIG_VIDEO_SED13806
816 Enable Epson SED13806 driver. This driver supports 8bpp
817 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
818 or CONFIG_VIDEO_SED13806_16BPP
823 Define this to enable a custom keyboard support.
824 This simply calls drv_keyboard_init() which must be
825 defined in your board-specific files.
826 The only board using this so far is RBC823.
828 - LCD Support: CONFIG_LCD
830 Define this to enable LCD support (for output to LCD
831 display); also select one of the supported displays
832 by defining one of these:
834 CONFIG_NEC_NL6648AC33:
836 NEC NL6648AC33-18. Active, color, single scan.
838 CONFIG_NEC_NL6648BC20
840 NEC NL6648BC20-08. 6.5", 640x480.
841 Active, color, single scan.
845 Sharp 320x240. Active, color, single scan.
846 It isn't 16x9, and I am not sure what it is.
848 CONFIG_SHARP_LQ64D341
850 Sharp LQ64D341 display, 640x480.
851 Active, color, single scan.
855 HLD1045 display, 640x480.
856 Active, color, single scan.
860 Optrex CBL50840-2 NF-FW 99 22 M5
862 Hitachi LMG6912RPFC-00T
866 320x240. Black & white.
868 Normally display is black on white background; define
869 CFG_WHITE_ON_BLACK to get it inverted.
871 - Splash Screen Support: CONFIG_SPLASH_SCREEN
873 If this option is set, the environment is checked for
874 a variable "splashimage". If found, the usual display
875 of logo, copyright and system information on the LCD
876 is supressed and the BMP image at the address
877 specified in "splashimage" is loaded instead. The
878 console is redirected to the "nulldev", too. This
879 allows for a "silent" boot where a splash screen is
880 loaded very quickly after power-on.
882 - Compression support:
885 If this option is set, support for bzip2 compressed
886 images is included. If not, only uncompressed and gzip
887 compressed images are supported.
889 NOTE: the bzip2 algorithm requires a lot of RAM, so
890 the malloc area (as defined by CFG_MALLOC_LEN) should
898 Define a default value for ethernet address to use
899 for the respective ethernet interface, in case this
900 is not determined automatically.
905 Define a default value for the IP address to use for
906 the default ethernet interface, in case this is not
907 determined through e.g. bootp.
912 Defines a default value for theIP address of a TFTP
913 server to contact when using the "tftboot" command.
915 - BOOTP Recovery Mode:
916 CONFIG_BOOTP_RANDOM_DELAY
918 If you have many targets in a network that try to
919 boot using BOOTP, you may want to avoid that all
920 systems send out BOOTP requests at precisely the same
921 moment (which would happen for instance at recovery
922 from a power failure, when all systems will try to
923 boot, thus flooding the BOOTP server. Defining
924 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
925 inserted before sending out BOOTP requests. The
926 following delays are insterted then:
928 1st BOOTP request: delay 0 ... 1 sec
929 2nd BOOTP request: delay 0 ... 2 sec
930 3rd BOOTP request: delay 0 ... 4 sec
932 BOOTP requests: delay 0 ... 8 sec
934 - DHCP Advanced Options:
937 You can fine tune the DHCP functionality by adding
938 these flags to the CONFIG_BOOTP_MASK define:
940 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
941 serverip from a DHCP server, it is possible that more
942 than one DNS serverip is offered to the client.
943 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
944 serverip will be stored in the additional environment
945 variable "dnsip2". The first DNS serverip is always
946 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
947 is added to the CONFIG_BOOTP_MASK.
949 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
950 to do a dynamic update of a DNS server. To do this, they
951 need the hostname of the DHCP requester.
952 If CONFIG_BOOP_SEND_HOSTNAME is added to the
953 CONFIG_BOOTP_MASK, the content of the "hostname"
954 environment variable is passed as option 12 to
957 - Status LED: CONFIG_STATUS_LED
959 Several configurations allow to display the current
960 status using a LED. For instance, the LED will blink
961 fast while running U-Boot code, stop blinking as
962 soon as a reply to a BOOTP request was received, and
963 start blinking slow once the Linux kernel is running
964 (supported by a status LED driver in the Linux
965 kernel). Defining CONFIG_STATUS_LED enables this
968 - CAN Support: CONFIG_CAN_DRIVER
970 Defining CONFIG_CAN_DRIVER enables CAN driver support
971 on those systems that support this (optional)
972 feature, like the TQM8xxL modules.
974 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
976 These enable I2C serial bus commands. Defining either of
977 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
978 include the appropriate I2C driver for the selected cpu.
980 This will allow you to use i2c commands at the u-boot
981 command line (as long as you set CFG_CMD_I2C in
982 CONFIG_COMMANDS) and communicate with i2c based realtime
983 clock chips. See common/cmd_i2c.c for a description of the
984 command line interface.
986 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
988 CONFIG_SOFT_I2C configures u-boot to use a software (aka
989 bit-banging) driver instead of CPM or similar hardware
992 There are several other quantities that must also be
993 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
995 In both cases you will need to define CFG_I2C_SPEED
996 to be the frequency (in Hz) at which you wish your i2c bus
997 to run and CFG_I2C_SLAVE to be the address of this node (ie
998 the cpu's i2c node address).
1000 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1001 sets the cpu up as a master node and so its address should
1002 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1003 p.16-473). So, set CFG_I2C_SLAVE to 0.
1005 That's all that's required for CONFIG_HARD_I2C.
1007 If you use the software i2c interface (CONFIG_SOFT_I2C)
1008 then the following macros need to be defined (examples are
1009 from include/configs/lwmon.h):
1013 (Optional). Any commands necessary to enable the I2C
1014 controller or configure ports.
1016 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1020 (Only for MPC8260 CPU). The I/O port to use (the code
1021 assumes both bits are on the same port). Valid values
1022 are 0..3 for ports A..D.
1026 The code necessary to make the I2C data line active
1027 (driven). If the data line is open collector, this
1030 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1034 The code necessary to make the I2C data line tri-stated
1035 (inactive). If the data line is open collector, this
1038 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1042 Code that returns TRUE if the I2C data line is high,
1045 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1049 If <bit> is TRUE, sets the I2C data line high. If it
1050 is FALSE, it clears it (low).
1052 eg: #define I2C_SDA(bit) \
1053 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1054 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1058 If <bit> is TRUE, sets the I2C clock line high. If it
1059 is FALSE, it clears it (low).
1061 eg: #define I2C_SCL(bit) \
1062 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1063 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1067 This delay is invoked four times per clock cycle so this
1068 controls the rate of data transfer. The data rate thus
1069 is 1 / (I2C_DELAY * 4). Often defined to be something
1072 #define I2C_DELAY udelay(2)
1076 When a board is reset during an i2c bus transfer
1077 chips might think that the current transfer is still
1078 in progress. On some boards it is possible to access
1079 the i2c SCLK line directly, either by using the
1080 processor pin as a GPIO or by having a second pin
1081 connected to the bus. If this option is defined a
1082 custom i2c_init_board() routine in boards/xxx/board.c
1083 is run early in the boot sequence.
1085 - SPI Support: CONFIG_SPI
1087 Enables SPI driver (so far only tested with
1088 SPI EEPROM, also an instance works with Crystal A/D and
1089 D/As on the SACSng board)
1093 Enables extended (16-bit) SPI EEPROM addressing.
1094 (symmetrical to CONFIG_I2C_X)
1098 Enables a software (bit-bang) SPI driver rather than
1099 using hardware support. This is a general purpose
1100 driver that only requires three general I/O port pins
1101 (two outputs, one input) to function. If this is
1102 defined, the board configuration must define several
1103 SPI configuration items (port pins to use, etc). For
1104 an example, see include/configs/sacsng.h.
1106 - FPGA Support: CONFIG_FPGA_COUNT
1108 Specify the number of FPGA devices to support.
1112 Used to specify the types of FPGA devices. For
1114 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1116 CFG_FPGA_PROG_FEEDBACK
1118 Enable printing of hash marks during FPGA
1123 Enable checks on FPGA configuration interface busy
1124 status by the configuration function. This option
1125 will require a board or device specific function to
1130 If defined, a function that provides delays in the
1131 FPGA configuration driver.
1133 CFG_FPGA_CHECK_CTRLC
1135 Allow Control-C to interrupt FPGA configuration
1137 CFG_FPGA_CHECK_ERROR
1139 Check for configuration errors during FPGA bitfile
1140 loading. For example, abort during Virtex II
1141 configuration if the INIT_B line goes low (which
1142 indicated a CRC error).
1146 Maximum time to wait for the INIT_B line to deassert
1147 after PROB_B has been deasserted during a Virtex II
1148 FPGA configuration sequence. The default time is 500 mS.
1152 Maximum time to wait for BUSY to deassert during
1153 Virtex II FPGA configuration. The default is 5 mS.
1155 CFG_FPGA_WAIT_CONFIG
1157 Time to wait after FPGA configuration. The default is
1160 - FPGA Support: CONFIG_FPGA_COUNT
1162 Specify the number of FPGA devices to support.
1166 Used to specify the types of FPGA devices. For example,
1167 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1169 CFG_FPGA_PROG_FEEDBACK
1171 Enable printing of hash marks during FPGA configuration.
1175 Enable checks on FPGA configuration interface busy
1176 status by the configuration function. This option
1177 will require a board or device specific function to
1182 If defined, a function that provides delays in the FPGA
1183 configuration driver.
1185 CFG_FPGA_CHECK_CTRLC
1186 Allow Control-C to interrupt FPGA configuration
1188 CFG_FPGA_CHECK_ERROR
1190 Check for configuration errors during FPGA bitfile
1191 loading. For example, abort during Virtex II
1192 configuration if the INIT_B line goes low (which
1193 indicated a CRC error).
1197 Maximum time to wait for the INIT_B line to deassert
1198 after PROB_B has been deasserted during a Virtex II
1199 FPGA configuration sequence. The default time is 500
1204 Maximum time to wait for BUSY to deassert during
1205 Virtex II FPGA configuration. The default is 5 mS.
1207 CFG_FPGA_WAIT_CONFIG
1209 Time to wait after FPGA configuration. The default is
1212 - Configuration Management:
1215 If defined, this string will be added to the U-Boot
1216 version information (U_BOOT_VERSION)
1218 - Vendor Parameter Protection:
1220 U-Boot considers the values of the environment
1221 variables "serial#" (Board Serial Number) and
1222 "ethaddr" (Ethernet Address) to be parameters that
1223 are set once by the board vendor / manufacturer, and
1224 protects these variables from casual modification by
1225 the user. Once set, these variables are read-only,
1226 and write or delete attempts are rejected. You can
1227 change this behviour:
1229 If CONFIG_ENV_OVERWRITE is #defined in your config
1230 file, the write protection for vendor parameters is
1231 completely disabled. Anybody can change or delete
1234 Alternatively, if you #define _both_ CONFIG_ETHADDR
1235 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1236 ethernet address is installed in the environment,
1237 which can be changed exactly ONCE by the user. [The
1238 serial# is unaffected by this, i. e. it remains
1244 Define this variable to enable the reservation of
1245 "protected RAM", i. e. RAM which is not overwritten
1246 by U-Boot. Define CONFIG_PRAM to hold the number of
1247 kB you want to reserve for pRAM. You can overwrite
1248 this default value by defining an environment
1249 variable "pram" to the number of kB you want to
1250 reserve. Note that the board info structure will
1251 still show the full amount of RAM. If pRAM is
1252 reserved, a new environment variable "mem" will
1253 automatically be defined to hold the amount of
1254 remaining RAM in a form that can be passed as boot
1255 argument to Linux, for instance like that:
1257 setenv bootargs ... mem=\$(mem)
1260 This way you can tell Linux not to use this memory,
1261 either, which results in a memory region that will
1262 not be affected by reboots.
1264 *WARNING* If your board configuration uses automatic
1265 detection of the RAM size, you must make sure that
1266 this memory test is non-destructive. So far, the
1267 following board configurations are known to be
1270 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1271 HERMES, IP860, RPXlite, LWMON, LANTEC,
1272 PCU_E, FLAGADM, TQM8260
1277 Define this variable to stop the system in case of a
1278 fatal error, so that you have to reset it manually.
1279 This is probably NOT a good idea for an embedded
1280 system where you want to system to reboot
1281 automatically as fast as possible, but it may be
1282 useful during development since you can try to debug
1283 the conditions that lead to the situation.
1285 CONFIG_NET_RETRY_COUNT
1287 This variable defines the number of retries for
1288 network operations like ARP, RARP, TFTP, or BOOTP
1289 before giving up the operation. If not defined, a
1290 default value of 5 is used.
1292 - Command Interpreter:
1295 Define this variable to enable the "hush" shell (from
1296 Busybox) as command line interpreter, thus enabling
1297 powerful command line syntax like
1298 if...then...else...fi conditionals or `&&' and '||'
1299 constructs ("shell scripts").
1301 If undefined, you get the old, much simpler behaviour
1302 with a somewhat smaller memory footprint.
1307 This defines the secondary prompt string, which is
1308 printed when the command interpreter needs more input
1309 to complete a command. Usually "> ".
1313 In the current implementation, the local variables
1314 space and global environment variables space are
1315 separated. Local variables are those you define by
1316 simply typing `name=value'. To access a local
1317 variable later on, you have write `$name' or
1318 `${name}'; to execute the contents of a variable
1319 directly type `$name' at the command prompt.
1321 Global environment variables are those you use
1322 setenv/printenv to work with. To run a command stored
1323 in such a variable, you need to use the run command,
1324 and you must not use the '$' sign to access them.
1326 To store commands and special characters in a
1327 variable, please use double quotation marks
1328 surrounding the whole text of the variable, instead
1329 of the backslashes before semicolons and special
1332 - Default Environment
1333 CONFIG_EXTRA_ENV_SETTINGS
1335 Define this to contain any number of null terminated
1336 strings (variable = value pairs) that will be part of
1337 the default environment compiled into the boot image.
1339 For example, place something like this in your
1340 board's config file:
1342 #define CONFIG_EXTRA_ENV_SETTINGS \
1346 Warning: This method is based on knowledge about the
1347 internal format how the environment is stored by the
1348 U-Boot code. This is NOT an official, exported
1349 interface! Although it is unlikely that this format
1350 will change soon, there is no guarantee either.
1351 You better know what you are doing here.
1353 Note: overly (ab)use of the default environment is
1354 discouraged. Make sure to check other ways to preset
1355 the environment like the autoscript function or the
1359 CONFIG_HAS_DATAFLASH
1361 Defining this option enables DataFlash features and
1362 allows to read/write in Dataflash via the standard
1365 - Show boot progress
1366 CONFIG_SHOW_BOOT_PROGRESS
1368 Defining this option allows to add some board-
1369 specific code (calling a user-provided function
1370 "show_boot_progress(int)") that enables you to show
1371 the system's boot progress on some display (for
1372 example, some LED's) on your board. At the moment,
1373 the following checkpoints are implemented:
1376 1 common/cmd_bootm.c before attempting to boot an image
1377 -1 common/cmd_bootm.c Image header has bad magic number
1378 2 common/cmd_bootm.c Image header has correct magic number
1379 -2 common/cmd_bootm.c Image header has bad checksum
1380 3 common/cmd_bootm.c Image header has correct checksum
1381 -3 common/cmd_bootm.c Image data has bad checksum
1382 4 common/cmd_bootm.c Image data has correct checksum
1383 -4 common/cmd_bootm.c Image is for unsupported architecture
1384 5 common/cmd_bootm.c Architecture check OK
1385 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1386 6 common/cmd_bootm.c Image Type check OK
1387 -6 common/cmd_bootm.c gunzip uncompression error
1388 -7 common/cmd_bootm.c Unimplemented compression type
1389 7 common/cmd_bootm.c Uncompression OK
1390 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1391 8 common/cmd_bootm.c Image Type check OK
1392 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1393 9 common/cmd_bootm.c Start initial ramdisk verification
1394 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1395 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1396 10 common/cmd_bootm.c Ramdisk header is OK
1397 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1398 11 common/cmd_bootm.c Ramdisk data has correct checksum
1399 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1400 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1401 13 common/cmd_bootm.c Start multifile image verification
1402 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1403 15 common/cmd_bootm.c All preparation done, transferring control to OS
1405 -1 common/cmd_doc.c Bad usage of "doc" command
1406 -1 common/cmd_doc.c No boot device
1407 -1 common/cmd_doc.c Unknown Chip ID on boot device
1408 -1 common/cmd_doc.c Read Error on boot device
1409 -1 common/cmd_doc.c Image header has bad magic number
1411 -1 common/cmd_ide.c Bad usage of "ide" command
1412 -1 common/cmd_ide.c No boot device
1413 -1 common/cmd_ide.c Unknown boot device
1414 -1 common/cmd_ide.c Unknown partition table
1415 -1 common/cmd_ide.c Invalid partition type
1416 -1 common/cmd_ide.c Read Error on boot device
1417 -1 common/cmd_ide.c Image header has bad magic number
1419 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1425 [so far only for SMDK2400 and TRAB boards]
1427 - Modem support endable:
1428 CONFIG_MODEM_SUPPORT
1430 - RTS/CTS Flow control enable:
1433 - Modem debug support:
1434 CONFIG_MODEM_SUPPORT_DEBUG
1436 Enables debugging stuff (char screen[1024], dbg())
1437 for modem support. Useful only with BDI2000.
1441 In the target system modem support is enabled when a
1442 specific key (key combination) is pressed during
1443 power-on. Otherwise U-Boot will boot normally
1444 (autoboot). The key_pressed() fuction is called from
1445 board_init(). Currently key_pressed() is a dummy
1446 function, returning 1 and thus enabling modem
1449 If there are no modem init strings in the
1450 environment, U-Boot proceed to autoboot; the
1451 previous output (banner, info printfs) will be
1454 See also: doc/README.Modem
1457 Configuration Settings:
1458 -----------------------
1460 - CFG_LONGHELP: Defined when you want long help messages included;
1461 undefine this when you're short of memory.
1463 - CFG_PROMPT: This is what U-Boot prints on the console to
1464 prompt for user input.
1466 - CFG_CBSIZE: Buffer size for input from the Console
1468 - CFG_PBSIZE: Buffer size for Console output
1470 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1472 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1473 the application (usually a Linux kernel) when it is
1476 - CFG_BAUDRATE_TABLE:
1477 List of legal baudrate settings for this board.
1479 - CFG_CONSOLE_INFO_QUIET
1480 Suppress display of console information at boot.
1482 - CFG_CONSOLE_IS_IN_ENV
1483 If the board specific function
1484 extern int overwrite_console (void);
1485 returns 1, the stdin, stderr and stdout are switched to the
1486 serial port, else the settings in the environment are used.
1488 - CFG_CONSOLE_OVERWRITE_ROUTINE
1489 Enable the call to overwrite_console().
1491 - CFG_CONSOLE_ENV_OVERWRITE
1492 Enable overwrite of previous console environment settings.
1494 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1495 Begin and End addresses of the area used by the
1499 Enable an alternate, more extensive memory test.
1501 - CFG_MEMTEST_SCRATCH:
1502 Scratch address used by the alternate memory test
1503 You only need to set this if address zero isn't writeable
1505 - CFG_TFTP_LOADADDR:
1506 Default load address for network file downloads
1508 - CFG_LOADS_BAUD_CHANGE:
1509 Enable temporary baudrate change while serial download
1512 Physical start address of SDRAM. _Must_ be 0 here.
1515 Physical start address of Motherboard I/O (if using a
1519 Physical start address of Flash memory.
1522 Physical start address of boot monitor code (set by
1523 make config files to be same as the text base address
1524 (TEXT_BASE) used when linking) - same as
1525 CFG_FLASH_BASE when booting from flash.
1528 Size of memory reserved for monitor code, used to
1529 determine _at_compile_time_ (!) if the environment is
1530 embedded within the U-Boot image, or in a separate
1534 Size of DRAM reserved for malloc() use.
1537 Maximum size of memory mapped by the startup code of
1538 the Linux kernel; all data that must be processed by
1539 the Linux kernel (bd_info, boot arguments, eventually
1540 initrd image) must be put below this limit.
1542 - CFG_MAX_FLASH_BANKS:
1543 Max number of Flash memory banks
1545 - CFG_MAX_FLASH_SECT:
1546 Max number of sectors on a Flash chip
1548 - CFG_FLASH_ERASE_TOUT:
1549 Timeout for Flash erase operations (in ms)
1551 - CFG_FLASH_WRITE_TOUT:
1552 Timeout for Flash write operations (in ms)
1554 - CFG_FLASH_LOCK_TOUT
1555 Timeout for Flash set sector lock bit operation (in ms)
1557 - CFG_FLASH_UNLOCK_TOUT
1558 Timeout for Flash clear lock bits operation (in ms)
1560 - CFG_FLASH_PROTECTION
1561 If defined, hardware flash sectors protection is used
1562 instead of U-Boot software protection.
1564 - CFG_DIRECT_FLASH_TFTP:
1566 Enable TFTP transfers directly to flash memory;
1567 without this option such a download has to be
1568 performed in two steps: (1) download to RAM, and (2)
1569 copy from RAM to flash.
1571 The two-step approach is usually more reliable, since
1572 you can check if the download worked before you erase
1573 the flash, but in some situations (when sytem RAM is
1574 too limited to allow for a tempory copy of the
1575 downloaded image) this option may be very useful.
1578 Define if the flash driver uses extra elements in the
1579 common flash structure for storing flash geometry
1581 - CFG_RX_ETH_BUFFER:
1582 Defines the number of ethernet receive buffers. On some
1583 ethernet controllers it is recommended to set this value
1584 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1585 buffers can be full shortly after enabling the interface
1586 on high ethernet traffic.
1587 Defaults to 4 if not defined.
1589 The following definitions that deal with the placement and management
1590 of environment data (variable area); in general, we support the
1591 following configurations:
1593 - CFG_ENV_IS_IN_FLASH:
1595 Define this if the environment is in flash memory.
1597 a) The environment occupies one whole flash sector, which is
1598 "embedded" in the text segment with the U-Boot code. This
1599 happens usually with "bottom boot sector" or "top boot
1600 sector" type flash chips, which have several smaller
1601 sectors at the start or the end. For instance, such a
1602 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1603 such a case you would place the environment in one of the
1604 4 kB sectors - with U-Boot code before and after it. With
1605 "top boot sector" type flash chips, you would put the
1606 environment in one of the last sectors, leaving a gap
1607 between U-Boot and the environment.
1611 Offset of environment data (variable area) to the
1612 beginning of flash memory; for instance, with bottom boot
1613 type flash chips the second sector can be used: the offset
1614 for this sector is given here.
1616 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1620 This is just another way to specify the start address of
1621 the flash sector containing the environment (instead of
1624 - CFG_ENV_SECT_SIZE:
1626 Size of the sector containing the environment.
1629 b) Sometimes flash chips have few, equal sized, BIG sectors.
1630 In such a case you don't want to spend a whole sector for
1635 If you use this in combination with CFG_ENV_IS_IN_FLASH
1636 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1637 of this flash sector for the environment. This saves
1638 memory for the RAM copy of the environment.
1640 It may also save flash memory if you decide to use this
1641 when your environment is "embedded" within U-Boot code,
1642 since then the remainder of the flash sector could be used
1643 for U-Boot code. It should be pointed out that this is
1644 STRONGLY DISCOURAGED from a robustness point of view:
1645 updating the environment in flash makes it always
1646 necessary to erase the WHOLE sector. If something goes
1647 wrong before the contents has been restored from a copy in
1648 RAM, your target system will be dead.
1650 - CFG_ENV_ADDR_REDUND
1653 These settings describe a second storage area used to hold
1654 a redundand copy of the environment data, so that there is
1655 a valid backup copy in case there is a power failure during
1656 a "saveenv" operation.
1658 BE CAREFUL! Any changes to the flash layout, and some changes to the
1659 source code will make it necessary to adapt <board>/u-boot.lds*
1663 - CFG_ENV_IS_IN_NVRAM:
1665 Define this if you have some non-volatile memory device
1666 (NVRAM, battery buffered SRAM) which you want to use for the
1672 These two #defines are used to determin the memory area you
1673 want to use for environment. It is assumed that this memory
1674 can just be read and written to, without any special
1677 BE CAREFUL! The first access to the environment happens quite early
1678 in U-Boot initalization (when we try to get the setting of for the
1679 console baudrate). You *MUST* have mappend your NVRAM area then, or
1682 Please note that even with NVRAM we still use a copy of the
1683 environment in RAM: we could work on NVRAM directly, but we want to
1684 keep settings there always unmodified except somebody uses "saveenv"
1685 to save the current settings.
1688 - CFG_ENV_IS_IN_EEPROM:
1690 Use this if you have an EEPROM or similar serial access
1691 device and a driver for it.
1696 These two #defines specify the offset and size of the
1697 environment area within the total memory of your EEPROM.
1699 - CFG_I2C_EEPROM_ADDR:
1700 If defined, specified the chip address of the EEPROM device.
1701 The default address is zero.
1703 - CFG_EEPROM_PAGE_WRITE_BITS:
1704 If defined, the number of bits used to address bytes in a
1705 single page in the EEPROM device. A 64 byte page, for example
1706 would require six bits.
1708 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1709 If defined, the number of milliseconds to delay between
1710 page writes. The default is zero milliseconds.
1712 - CFG_I2C_EEPROM_ADDR_LEN:
1713 The length in bytes of the EEPROM memory array address. Note
1714 that this is NOT the chip address length!
1717 The size in bytes of the EEPROM device.
1720 - CFG_SPI_INIT_OFFSET
1722 Defines offset to the initial SPI buffer area in DPRAM. The
1723 area is used at an early stage (ROM part) if the environment
1724 is configured to reside in the SPI EEPROM: We need a 520 byte
1725 scratch DPRAM area. It is used between the two initialization
1726 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1727 to be a good choice since it makes it far enough from the
1728 start of the data area as well as from the stack pointer.
1730 Please note that the environment is read-only as long as the monitor
1731 has been relocated to RAM and a RAM copy of the environment has been
1732 created; also, when using EEPROM you will have to use getenv_r()
1733 until then to read environment variables.
1735 The environment is protected by a CRC32 checksum. Before the monitor
1736 is relocated into RAM, as a result of a bad CRC you will be working
1737 with the compiled-in default environment - *silently*!!! [This is
1738 necessary, because the first environment variable we need is the
1739 "baudrate" setting for the console - if we have a bad CRC, we don't
1740 have any device yet where we could complain.]
1742 Note: once the monitor has been relocated, then it will complain if
1743 the default environment is used; a new CRC is computed as soon as you
1744 use the "saveenv" command to store a valid environment.
1747 Low Level (hardware related) configuration options:
1748 ---------------------------------------------------
1750 - CFG_CACHELINE_SIZE:
1751 Cache Line Size of the CPU.
1754 Default address of the IMMR after system reset.
1756 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1757 and RPXsuper) to be able to adjust the position of
1758 the IMMR register after a reset.
1760 - Floppy Disk Support:
1761 CFG_FDC_DRIVE_NUMBER
1763 the default drive number (default value 0)
1767 defines the spacing between fdc chipset registers
1772 defines the offset of register from address. It
1773 depends on which part of the data bus is connected to
1774 the fdc chipset. (default value 0)
1776 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1777 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1780 if CFG_FDC_HW_INIT is defined, then the function
1781 fdc_hw_init() is called at the beginning of the FDC
1782 setup. fdc_hw_init() must be provided by the board
1783 source code. It is used to make hardware dependant
1786 - CFG_IMMR: Physical address of the Internal Memory Mapped
1787 Register; DO NOT CHANGE! (11-4)
1788 [MPC8xx systems only]
1790 - CFG_INIT_RAM_ADDR:
1792 Start address of memory area that can be used for
1793 initial data and stack; please note that this must be
1794 writable memory that is working WITHOUT special
1795 initialization, i. e. you CANNOT use normal RAM which
1796 will become available only after programming the
1797 memory controller and running certain initialization
1800 U-Boot uses the following memory types:
1801 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1802 - MPC824X: data cache
1803 - PPC4xx: data cache
1805 - CFG_GBL_DATA_OFFSET:
1807 Offset of the initial data structure in the memory
1808 area defined by CFG_INIT_RAM_ADDR. Usually
1809 CFG_GBL_DATA_OFFSET is chosen such that the initial
1810 data is located at the end of the available space
1811 (sometimes written as (CFG_INIT_RAM_END -
1812 CFG_INIT_DATA_SIZE), and the initial stack is just
1813 below that area (growing from (CFG_INIT_RAM_ADDR +
1814 CFG_GBL_DATA_OFFSET) downward.
1817 On the MPC824X (or other systems that use the data
1818 cache for initial memory) the address chosen for
1819 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1820 point to an otherwise UNUSED address space between
1821 the top of RAM and the start of the PCI space.
1823 - CFG_SIUMCR: SIU Module Configuration (11-6)
1825 - CFG_SYPCR: System Protection Control (11-9)
1827 - CFG_TBSCR: Time Base Status and Control (11-26)
1829 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1831 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1833 - CFG_SCCR: System Clock and reset Control Register (15-27)
1835 - CFG_OR_TIMING_SDRAM:
1839 periodic timer for refresh
1841 - CFG_DER: Debug Event Register (37-47)
1843 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1844 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1845 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1847 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1849 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1850 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1851 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1852 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1854 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1855 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1856 Machine Mode Register and Memory Periodic Timer
1857 Prescaler definitions (SDRAM timing)
1859 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1860 enable I2C microcode relocation patch (MPC8xx);
1861 define relocation offset in DPRAM [DSP2]
1863 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1864 enable SPI microcode relocation patch (MPC8xx);
1865 define relocation offset in DPRAM [SCC4]
1868 Use OSCM clock mode on MBX8xx board. Be careful,
1869 wrong setting might damage your board. Read
1870 doc/README.MBX before setting this variable!
1872 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1873 Offset of the bootmode word in DPRAM used by post
1874 (Power On Self Tests). This definition overrides
1875 #define'd default value in commproc.h resp.
1878 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1879 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1880 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1881 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1882 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1883 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1884 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1885 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1886 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1888 Building the Software:
1889 ======================
1891 Building U-Boot has been tested in native PPC environments (on a
1892 PowerBook G3 running LinuxPPC 2000) and in cross environments
1893 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1896 If you are not using a native PPC environment, it is assumed that you
1897 have the GNU cross compiling tools available in your path and named
1898 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1899 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1900 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1903 CROSS_COMPILE = ppc_4xx-
1906 U-Boot is intended to be simple to build. After installing the
1907 sources you must configure U-Boot for one specific board type. This
1912 where "NAME_config" is the name of one of the existing
1913 configurations; the following names are supported:
1915 ADCIOP_config GTH_config TQM850L_config
1916 ADS860_config IP860_config TQM855L_config
1917 AR405_config IVML24_config TQM860L_config
1918 CANBT_config IVMS8_config WALNUT405_config
1919 CPCI405_config LANTEC_config cogent_common_config
1920 CPCIISER4_config MBX_config cogent_mpc8260_config
1921 CU824_config MBX860T_config cogent_mpc8xx_config
1922 ESTEEM192E_config RPXlite_config hermes_config
1923 ETX094_config RPXsuper_config hymod_config
1924 FADS823_config SM850_config lwmon_config
1925 FADS850SAR_config SPD823TS_config pcu_e_config
1926 FADS860T_config SXNI855T_config rsdproto_config
1927 FPS850L_config Sandpoint8240_config sbc8260_config
1928 GENIETV_config TQM823L_config PIP405_config
1929 GEN860T_config EBONY_config FPS860L_config
1930 ELPT860_config cmi_mpc5xx_config NETVIA_config
1931 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
1933 Note: for some board special configuration names may exist; check if
1934 additional information is available from the board vendor; for
1935 instance, the TQM8xxL systems run normally at 50 MHz and use a
1936 SCC for 10baseT ethernet; there are also systems with 80 MHz
1937 CPU clock, and an optional Fast Ethernet module is available
1938 for CPU's with FEC. You can select such additional "features"
1939 when chosing the configuration, i. e.
1942 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1944 make TQM860L_FEC_config
1945 - will configure for a TQM860L at 50MHz with FEC for ethernet
1947 make TQM860L_80MHz_config
1948 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1951 make TQM860L_FEC_80MHz_config
1952 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1954 make TQM823L_LCD_config
1955 - will configure for a TQM823L with U-Boot console on LCD
1957 make TQM823L_LCD_80MHz_config
1958 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1963 Finally, type "make all", and you should get some working U-Boot
1964 images ready for download to / installation on your system:
1966 - "u-boot.bin" is a raw binary image
1967 - "u-boot" is an image in ELF binary format
1968 - "u-boot.srec" is in Motorola S-Record format
1971 Please be aware that the Makefiles assume you are using GNU make, so
1972 for instance on NetBSD you might need to use "gmake" instead of
1976 If the system board that you have is not listed, then you will need
1977 to port U-Boot to your hardware platform. To do this, follow these
1980 1. Add a new configuration option for your board to the toplevel
1981 "Makefile" and to the "MAKEALL" script, using the existing
1982 entries as examples. Note that here and at many other places
1983 boards and other names are listed in alphabetical sort order. Please
1985 2. Create a new directory to hold your board specific code. Add any
1986 files you need. In your board directory, you will need at least
1987 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1988 3. Create a new configuration file "include/configs/<board>.h" for
1990 3. If you're porting U-Boot to a new CPU, then also create a new
1991 directory to hold your CPU specific code. Add any files you need.
1992 4. Run "make <board>_config" with your new name.
1993 5. Type "make", and you should get a working "u-boot.srec" file
1994 to be installed on your target system.
1995 6. Debug and solve any problems that might arise.
1996 [Of course, this last step is much harder than it sounds.]
1999 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2000 ==============================================================
2002 If you have modified U-Boot sources (for instance added a new board
2003 or support for new devices, a new CPU, etc.) you are expected to
2004 provide feedback to the other developers. The feedback normally takes
2005 the form of a "patch", i. e. a context diff against a certain (latest
2006 official or latest in CVS) version of U-Boot sources.
2008 But before you submit such a patch, please verify that your modifi-
2009 cation did not break existing code. At least make sure that *ALL* of
2010 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2011 just run the "MAKEALL" script, which will configure and build U-Boot
2012 for ALL supported system. Be warned, this will take a while. You can
2013 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2014 environment variable to the script, i. e. to use the cross tools from
2015 MontaVista's Hard Hat Linux you can type
2017 CROSS_COMPILE=ppc_8xx- MAKEALL
2019 or to build on a native PowerPC system you can type
2021 CROSS_COMPILE=' ' MAKEALL
2023 See also "U-Boot Porting Guide" below.
2026 Monitor Commands - Overview:
2027 ============================
2029 go - start application at address 'addr'
2030 run - run commands in an environment variable
2031 bootm - boot application image from memory
2032 bootp - boot image via network using BootP/TFTP protocol
2033 tftpboot- boot image via network using TFTP protocol
2034 and env variables "ipaddr" and "serverip"
2035 (and eventually "gatewayip")
2036 rarpboot- boot image via network using RARP/TFTP protocol
2037 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2038 loads - load S-Record file over serial line
2039 loadb - load binary file over serial line (kermit mode)
2041 mm - memory modify (auto-incrementing)
2042 nm - memory modify (constant address)
2043 mw - memory write (fill)
2045 cmp - memory compare
2046 crc32 - checksum calculation
2047 imd - i2c memory display
2048 imm - i2c memory modify (auto-incrementing)
2049 inm - i2c memory modify (constant address)
2050 imw - i2c memory write (fill)
2051 icrc32 - i2c checksum calculation
2052 iprobe - probe to discover valid I2C chip addresses
2053 iloop - infinite loop on address range
2054 isdram - print SDRAM configuration information
2055 sspi - SPI utility commands
2056 base - print or set address offset
2057 printenv- print environment variables
2058 setenv - set environment variables
2059 saveenv - save environment variables to persistent storage
2060 protect - enable or disable FLASH write protection
2061 erase - erase FLASH memory
2062 flinfo - print FLASH memory information
2063 bdinfo - print Board Info structure
2064 iminfo - print header information for application image
2065 coninfo - print console devices and informations
2066 ide - IDE sub-system
2067 loop - infinite loop on address range
2068 mtest - simple RAM test
2069 icache - enable or disable instruction cache
2070 dcache - enable or disable data cache
2071 reset - Perform RESET of the CPU
2072 echo - echo args to console
2073 version - print monitor version
2074 help - print online help
2075 ? - alias for 'help'
2078 Monitor Commands - Detailed Description:
2079 ========================================
2083 For now: just type "help <command>".
2086 Environment Variables:
2087 ======================
2089 U-Boot supports user configuration using Environment Variables which
2090 can be made persistent by saving to Flash memory.
2092 Environment Variables are set using "setenv", printed using
2093 "printenv", and saved to Flash using "saveenv". Using "setenv"
2094 without a value can be used to delete a variable from the
2095 environment. As long as you don't save the environment you are
2096 working with an in-memory copy. In case the Flash area containing the
2097 environment is erased by accident, a default environment is provided.
2099 Some configuration options can be set using Environment Variables:
2101 baudrate - see CONFIG_BAUDRATE
2103 bootdelay - see CONFIG_BOOTDELAY
2105 bootcmd - see CONFIG_BOOTCOMMAND
2107 bootargs - Boot arguments when booting an RTOS image
2109 bootfile - Name of the image to load with TFTP
2111 autoload - if set to "no" (any string beginning with 'n'),
2112 "bootp" will just load perform a lookup of the
2113 configuration from the BOOTP server, but not try to
2114 load any image using TFTP
2116 autostart - if set to "yes", an image loaded using the "bootp",
2117 "rarpboot", "tftpboot" or "diskboot" commands will
2118 be automatically started (by internally calling
2121 If set to "no", a standalone image passed to the
2122 "bootm" command will be copied to the load address
2123 (and eventually uncompressed), but NOT be started.
2124 This can be used to load and uncompress arbitrary
2127 initrd_high - restrict positioning of initrd images:
2128 If this variable is not set, initrd images will be
2129 copied to the highest possible address in RAM; this
2130 is usually what you want since it allows for
2131 maximum initrd size. If for some reason you want to
2132 make sure that the initrd image is loaded below the
2133 CFG_BOOTMAPSZ limit, you can set this environment
2134 variable to a value of "no" or "off" or "0".
2135 Alternatively, you can set it to a maximum upper
2136 address to use (U-Boot will still check that it
2137 does not overwrite the U-Boot stack and data).
2139 For instance, when you have a system with 16 MB
2140 RAM, and want to reserve 4 MB from use by Linux,
2141 you can do this by adding "mem=12M" to the value of
2142 the "bootargs" variable. However, now you must make
2143 sure that the initrd image is placed in the first
2144 12 MB as well - this can be done with
2146 setenv initrd_high 00c00000
2148 If you set initrd_high to 0xFFFFFFFF, this is an
2149 indication to U-Boot that all addresses are legal
2150 for the Linux kernel, including addresses in flash
2151 memory. In this case U-Boot will NOT COPY the
2152 ramdisk at all. This may be useful to reduce the
2153 boot time on your system, but requires that this
2154 feature is supported by your Linux kernel.
2156 ipaddr - IP address; needed for tftpboot command
2158 loadaddr - Default load address for commands like "bootp",
2159 "rarpboot", "tftpboot", "loadb" or "diskboot"
2161 loads_echo - see CONFIG_LOADS_ECHO
2163 serverip - TFTP server IP address; needed for tftpboot command
2165 bootretry - see CONFIG_BOOT_RETRY_TIME
2167 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2169 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2172 The following environment variables may be used and automatically
2173 updated by the network boot commands ("bootp" and "rarpboot"),
2174 depending the information provided by your boot server:
2176 bootfile - see above
2177 dnsip - IP address of your Domain Name Server
2178 dnsip2 - IP address of your secondary Domain Name Server
2179 gatewayip - IP address of the Gateway (Router) to use
2180 hostname - Target hostname
2182 netmask - Subnet Mask
2183 rootpath - Pathname of the root filesystem on the NFS server
2184 serverip - see above
2187 There are two special Environment Variables:
2189 serial# - contains hardware identification information such
2190 as type string and/or serial number
2191 ethaddr - Ethernet address
2193 These variables can be set only once (usually during manufacturing of
2194 the board). U-Boot refuses to delete or overwrite these variables
2195 once they have been set once.
2198 Further special Environment Variables:
2200 ver - Contains the U-Boot version string as printed
2201 with the "version" command. This variable is
2202 readonly (see CONFIG_VERSION_VARIABLE).
2205 Please note that changes to some configuration parameters may take
2206 only effect after the next boot (yes, that's just like Windoze :-).
2209 Command Line Parsing:
2210 =====================
2212 There are two different command line parsers available with U-Boot:
2213 the old "simple" one, and the much more powerful "hush" shell:
2215 Old, simple command line parser:
2216 --------------------------------
2218 - supports environment variables (through setenv / saveenv commands)
2219 - several commands on one line, separated by ';'
2220 - variable substitution using "... $(name) ..." syntax
2221 - special characters ('$', ';') can be escaped by prefixing with '\',
2223 setenv bootcmd bootm \$(address)
2224 - You can also escape text by enclosing in single apostrophes, for example:
2225 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2230 - similar to Bourne shell, with control structures like
2231 if...then...else...fi, for...do...done; while...do...done,
2232 until...do...done, ...
2233 - supports environment ("global") variables (through setenv / saveenv
2234 commands) and local shell variables (through standard shell syntax
2235 "name=value"); only environment variables can be used with "run"
2241 (1) If a command line (or an environment variable executed by a "run"
2242 command) contains several commands separated by semicolon, and
2243 one of these commands fails, then the remaining commands will be
2246 (2) If you execute several variables with one call to run (i. e.
2247 calling run with a list af variables as arguments), any failing
2248 command will cause "run" to terminate, i. e. the remaining
2249 variables are not executed.
2251 Note for Redundant Ethernet Interfaces:
2252 =======================================
2254 Some boards come with redundant ethernet interfaces; U-Boot supports
2255 such configurations and is capable of automatic selection of a
2256 "working" interface when needed. MAC assignment works as follows:
2258 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2259 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2260 "eth1addr" (=>eth1), "eth2addr", ...
2262 If the network interface stores some valid MAC address (for instance
2263 in SROM), this is used as default address if there is NO correspon-
2264 ding setting in the environment; if the corresponding environment
2265 variable is set, this overrides the settings in the card; that means:
2267 o If the SROM has a valid MAC address, and there is no address in the
2268 environment, the SROM's address is used.
2270 o If there is no valid address in the SROM, and a definition in the
2271 environment exists, then the value from the environment variable is
2274 o If both the SROM and the environment contain a MAC address, and
2275 both addresses are the same, this MAC address is used.
2277 o If both the SROM and the environment contain a MAC address, and the
2278 addresses differ, the value from the environment is used and a
2281 o If neither SROM nor the environment contain a MAC address, an error
2288 The "boot" commands of this monitor operate on "image" files which
2289 can be basicly anything, preceeded by a special header; see the
2290 definitions in include/image.h for details; basicly, the header
2291 defines the following image properties:
2293 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2294 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2295 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2296 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2297 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2298 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2299 Currently supported: PowerPC).
2300 * Compression Type (uncompressed, gzip, bzip2)
2306 The header is marked by a special Magic Number, and both the header
2307 and the data portions of the image are secured against corruption by
2314 Although U-Boot should support any OS or standalone application
2315 easily, the main focus has always been on Linux during the design of
2318 U-Boot includes many features that so far have been part of some
2319 special "boot loader" code within the Linux kernel. Also, any
2320 "initrd" images to be used are no longer part of one big Linux image;
2321 instead, kernel and "initrd" are separate images. This implementation
2322 serves several purposes:
2324 - the same features can be used for other OS or standalone
2325 applications (for instance: using compressed images to reduce the
2326 Flash memory footprint)
2328 - it becomes much easier to port new Linux kernel versions because
2329 lots of low-level, hardware dependent stuff are done by U-Boot
2331 - the same Linux kernel image can now be used with different "initrd"
2332 images; of course this also means that different kernel images can
2333 be run with the same "initrd". This makes testing easier (you don't
2334 have to build a new "zImage.initrd" Linux image when you just
2335 change a file in your "initrd"). Also, a field-upgrade of the
2336 software is easier now.
2342 Porting Linux to U-Boot based systems:
2343 ---------------------------------------
2345 U-Boot cannot save you from doing all the necessary modifications to
2346 configure the Linux device drivers for use with your target hardware
2347 (no, we don't intend to provide a full virtual machine interface to
2350 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2352 Just make sure your machine specific header file (for instance
2353 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2354 Information structure as we define in include/u-boot.h, and make
2355 sure that your definition of IMAP_ADDR uses the same value as your
2356 U-Boot configuration in CFG_IMMR.
2359 Configuring the Linux kernel:
2360 -----------------------------
2362 No specific requirements for U-Boot. Make sure you have some root
2363 device (initial ramdisk, NFS) for your target system.
2366 Building a Linux Image:
2367 -----------------------
2369 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2370 not used. If you use recent kernel source, a new build target
2371 "uImage" will exist which automatically builds an image usable by
2372 U-Boot. Most older kernels also have support for a "pImage" target,
2373 which was introduced for our predecessor project PPCBoot and uses a
2374 100% compatible format.
2383 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2384 encapsulate a compressed Linux kernel image with header information,
2385 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2387 * build a standard "vmlinux" kernel image (in ELF binary format):
2389 * convert the kernel into a raw binary image:
2391 ${CROSS_COMPILE}-objcopy -O binary \
2392 -R .note -R .comment \
2393 -S vmlinux linux.bin
2395 * compress the binary image:
2399 * package compressed binary image for U-Boot:
2401 mkimage -A ppc -O linux -T kernel -C gzip \
2402 -a 0 -e 0 -n "Linux Kernel Image" \
2403 -d linux.bin.gz uImage
2406 The "mkimage" tool can also be used to create ramdisk images for use
2407 with U-Boot, either separated from the Linux kernel image, or
2408 combined into one file. "mkimage" encapsulates the images with a 64
2409 byte header containing information about target architecture,
2410 operating system, image type, compression method, entry points, time
2411 stamp, CRC32 checksums, etc.
2413 "mkimage" can be called in two ways: to verify existing images and
2414 print the header information, or to build new images.
2416 In the first form (with "-l" option) mkimage lists the information
2417 contained in the header of an existing U-Boot image; this includes
2418 checksum verification:
2420 tools/mkimage -l image
2421 -l ==> list image header information
2423 The second form (with "-d" option) is used to build a U-Boot image
2424 from a "data file" which is used as image payload:
2426 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2427 -n name -d data_file image
2428 -A ==> set architecture to 'arch'
2429 -O ==> set operating system to 'os'
2430 -T ==> set image type to 'type'
2431 -C ==> set compression type 'comp'
2432 -a ==> set load address to 'addr' (hex)
2433 -e ==> set entry point to 'ep' (hex)
2434 -n ==> set image name to 'name'
2435 -d ==> use image data from 'datafile'
2437 Right now, all Linux kernels use the same load address (0x00000000),
2438 but the entry point address depends on the kernel version:
2440 - 2.2.x kernels have the entry point at 0x0000000C,
2441 - 2.3.x and later kernels have the entry point at 0x00000000.
2443 So a typical call to build a U-Boot image would read:
2445 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2446 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2447 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2448 > examples/uImage.TQM850L
2449 Image Name: 2.4.4 kernel for TQM850L
2450 Created: Wed Jul 19 02:34:59 2000
2451 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2452 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2453 Load Address: 0x00000000
2454 Entry Point: 0x00000000
2456 To verify the contents of the image (or check for corruption):
2458 -> tools/mkimage -l examples/uImage.TQM850L
2459 Image Name: 2.4.4 kernel for TQM850L
2460 Created: Wed Jul 19 02:34:59 2000
2461 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2462 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2463 Load Address: 0x00000000
2464 Entry Point: 0x00000000
2466 NOTE: for embedded systems where boot time is critical you can trade
2467 speed for memory and install an UNCOMPRESSED image instead: this
2468 needs more space in Flash, but boots much faster since it does not
2469 need to be uncompressed:
2471 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2472 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2473 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2474 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2475 > examples/uImage.TQM850L-uncompressed
2476 Image Name: 2.4.4 kernel for TQM850L
2477 Created: Wed Jul 19 02:34:59 2000
2478 Image Type: PowerPC Linux Kernel Image (uncompressed)
2479 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2480 Load Address: 0x00000000
2481 Entry Point: 0x00000000
2484 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2485 when your kernel is intended to use an initial ramdisk:
2487 -> tools/mkimage -n 'Simple Ramdisk Image' \
2488 > -A ppc -O linux -T ramdisk -C gzip \
2489 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2490 Image Name: Simple Ramdisk Image
2491 Created: Wed Jan 12 14:01:50 2000
2492 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2493 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2494 Load Address: 0x00000000
2495 Entry Point: 0x00000000
2498 Installing a Linux Image:
2499 -------------------------
2501 To downloading a U-Boot image over the serial (console) interface,
2502 you must convert the image to S-Record format:
2504 objcopy -I binary -O srec examples/image examples/image.srec
2506 The 'objcopy' does not understand the information in the U-Boot
2507 image header, so the resulting S-Record file will be relative to
2508 address 0x00000000. To load it to a given address, you need to
2509 specify the target address as 'offset' parameter with the 'loads'
2512 Example: install the image to address 0x40100000 (which on the
2513 TQM8xxL is in the first Flash bank):
2515 => erase 40100000 401FFFFF
2521 ## Ready for S-Record download ...
2522 ~>examples/image.srec
2523 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2525 15989 15990 15991 15992
2526 [file transfer complete]
2528 ## Start Addr = 0x00000000
2531 You can check the success of the download using the 'iminfo' command;
2532 this includes a checksum verification so you can be sure no data
2533 corruption happened:
2537 ## Checking Image at 40100000 ...
2538 Image Name: 2.2.13 for initrd on TQM850L
2539 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2540 Data Size: 335725 Bytes = 327 kB = 0 MB
2541 Load Address: 00000000
2542 Entry Point: 0000000c
2543 Verifying Checksum ... OK
2549 The "bootm" command is used to boot an application that is stored in
2550 memory (RAM or Flash). In case of a Linux kernel image, the contents
2551 of the "bootargs" environment variable is passed to the kernel as
2552 parameters. You can check and modify this variable using the
2553 "printenv" and "setenv" commands:
2556 => printenv bootargs
2557 bootargs=root=/dev/ram
2559 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2561 => printenv bootargs
2562 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2565 ## Booting Linux kernel at 40020000 ...
2566 Image Name: 2.2.13 for NFS on TQM850L
2567 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2568 Data Size: 381681 Bytes = 372 kB = 0 MB
2569 Load Address: 00000000
2570 Entry Point: 0000000c
2571 Verifying Checksum ... OK
2572 Uncompressing Kernel Image ... OK
2573 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
2574 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2575 time_init: decrementer frequency = 187500000/60
2576 Calibrating delay loop... 49.77 BogoMIPS
2577 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2580 If you want to boot a Linux kernel with initial ram disk, you pass
2581 the memory addresses of both the kernel and the initrd image (PPBCOOT
2582 format!) to the "bootm" command:
2584 => imi 40100000 40200000
2586 ## Checking Image at 40100000 ...
2587 Image Name: 2.2.13 for initrd on TQM850L
2588 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2589 Data Size: 335725 Bytes = 327 kB = 0 MB
2590 Load Address: 00000000
2591 Entry Point: 0000000c
2592 Verifying Checksum ... OK
2594 ## Checking Image at 40200000 ...
2595 Image Name: Simple Ramdisk Image
2596 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2597 Data Size: 566530 Bytes = 553 kB = 0 MB
2598 Load Address: 00000000
2599 Entry Point: 00000000
2600 Verifying Checksum ... OK
2602 => bootm 40100000 40200000
2603 ## Booting Linux kernel at 40100000 ...
2604 Image Name: 2.2.13 for initrd on TQM850L
2605 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2606 Data Size: 335725 Bytes = 327 kB = 0 MB
2607 Load Address: 00000000
2608 Entry Point: 0000000c
2609 Verifying Checksum ... OK
2610 Uncompressing Kernel Image ... OK
2611 ## Loading RAMDisk Image at 40200000 ...
2612 Image Name: Simple Ramdisk Image
2613 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2614 Data Size: 566530 Bytes = 553 kB = 0 MB
2615 Load Address: 00000000
2616 Entry Point: 00000000
2617 Verifying Checksum ... OK
2618 Loading Ramdisk ... OK
2619 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
2620 Boot arguments: root=/dev/ram
2621 time_init: decrementer frequency = 187500000/60
2622 Calibrating delay loop... 49.77 BogoMIPS
2624 RAMDISK: Compressed image found at block 0
2625 VFS: Mounted root (ext2 filesystem).
2629 More About U-Boot Image Types:
2630 ------------------------------
2632 U-Boot supports the following image types:
2634 "Standalone Programs" are directly runnable in the environment
2635 provided by U-Boot; it is expected that (if they behave
2636 well) you can continue to work in U-Boot after return from
2637 the Standalone Program.
2638 "OS Kernel Images" are usually images of some Embedded OS which
2639 will take over control completely. Usually these programs
2640 will install their own set of exception handlers, device
2641 drivers, set up the MMU, etc. - this means, that you cannot
2642 expect to re-enter U-Boot except by resetting the CPU.
2643 "RAMDisk Images" are more or less just data blocks, and their
2644 parameters (address, size) are passed to an OS kernel that is
2646 "Multi-File Images" contain several images, typically an OS
2647 (Linux) kernel image and one or more data images like
2648 RAMDisks. This construct is useful for instance when you want
2649 to boot over the network using BOOTP etc., where the boot
2650 server provides just a single image file, but you want to get
2651 for instance an OS kernel and a RAMDisk image.
2653 "Multi-File Images" start with a list of image sizes, each
2654 image size (in bytes) specified by an "uint32_t" in network
2655 byte order. This list is terminated by an "(uint32_t)0".
2656 Immediately after the terminating 0 follow the images, one by
2657 one, all aligned on "uint32_t" boundaries (size rounded up to
2658 a multiple of 4 bytes).
2660 "Firmware Images" are binary images containing firmware (like
2661 U-Boot or FPGA images) which usually will be programmed to
2664 "Script files" are command sequences that will be executed by
2665 U-Boot's command interpreter; this feature is especially
2666 useful when you configure U-Boot to use a real shell (hush)
2667 as command interpreter.
2673 One of the features of U-Boot is that you can dynamically load and
2674 run "standalone" applications, which can use some resources of
2675 U-Boot like console I/O functions or interrupt services.
2677 Two simple examples are included with the sources:
2682 'examples/hello_world.c' contains a small "Hello World" Demo
2683 application; it is automatically compiled when you build U-Boot.
2684 It's configured to run at address 0x00040004, so you can play with it
2688 ## Ready for S-Record download ...
2689 ~>examples/hello_world.srec
2690 1 2 3 4 5 6 7 8 9 10 11 ...
2691 [file transfer complete]
2693 ## Start Addr = 0x00040004
2695 => go 40004 Hello World! This is a test.
2696 ## Starting application at 0x00040004 ...
2707 Hit any key to exit ...
2709 ## Application terminated, rc = 0x0
2711 Another example, which demonstrates how to register a CPM interrupt
2712 handler with the U-Boot code, can be found in 'examples/timer.c'.
2713 Here, a CPM timer is set up to generate an interrupt every second.
2714 The interrupt service routine is trivial, just printing a '.'
2715 character, but this is just a demo program. The application can be
2716 controlled by the following keys:
2718 ? - print current values og the CPM Timer registers
2719 b - enable interrupts and start timer
2720 e - stop timer and disable interrupts
2721 q - quit application
2724 ## Ready for S-Record download ...
2725 ~>examples/timer.srec
2726 1 2 3 4 5 6 7 8 9 10 11 ...
2727 [file transfer complete]
2729 ## Start Addr = 0x00040004
2732 ## Starting application at 0x00040004 ...
2735 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2738 [q, b, e, ?] Set interval 1000000 us
2741 [q, b, e, ?] ........
2742 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2745 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2748 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2751 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2753 [q, b, e, ?] ...Stopping timer
2755 [q, b, e, ?] ## Application terminated, rc = 0x0
2761 Over time, many people have reported problems when trying to use the
2762 "minicom" terminal emulation program for serial download. I (wd)
2763 consider minicom to be broken, and recommend not to use it. Under
2764 Unix, I recommend to use C-Kermit for general purpose use (and
2765 especially for kermit binary protocol download ("loadb" command), and
2766 use "cu" for S-Record download ("loads" command).
2768 Nevertheless, if you absolutely want to use it try adding this
2769 configuration to your "File transfer protocols" section:
2771 Name Program Name U/D FullScr IO-Red. Multi
2772 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2773 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2779 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2780 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2782 Building requires a cross environment; it is known to work on
2783 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2784 need gmake since the Makefiles are not compatible with BSD make).
2785 Note that the cross-powerpc package does not install include files;
2786 attempting to build U-Boot will fail because <machine/ansi.h> is
2787 missing. This file has to be installed and patched manually:
2789 # cd /usr/pkg/cross/powerpc-netbsd/include
2791 # ln -s powerpc machine
2792 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2793 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2795 Native builds *don't* work due to incompatibilities between native
2796 and U-Boot include files.
2798 Booting assumes that (the first part of) the image booted is a
2799 stage-2 loader which in turn loads and then invokes the kernel
2800 proper. Loader sources will eventually appear in the NetBSD source
2801 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2802 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2806 Implementation Internals:
2807 =========================
2809 The following is not intended to be a complete description of every
2810 implementation detail. However, it should help to understand the
2811 inner workings of U-Boot and make it easier to port it to custom
2815 Initial Stack, Global Data:
2816 ---------------------------
2818 The implementation of U-Boot is complicated by the fact that U-Boot
2819 starts running out of ROM (flash memory), usually without access to
2820 system RAM (because the memory controller is not initialized yet).
2821 This means that we don't have writable Data or BSS segments, and BSS
2822 is not initialized as zero. To be able to get a C environment working
2823 at all, we have to allocate at least a minimal stack. Implementation
2824 options for this are defined and restricted by the CPU used: Some CPU
2825 models provide on-chip memory (like the IMMR area on MPC8xx and
2826 MPC826x processors), on others (parts of) the data cache can be
2827 locked as (mis-) used as memory, etc.
2829 Chris Hallinan posted a good summary of these issues to the
2830 u-boot-users mailing list:
2832 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2833 From: "Chris Hallinan" <clh@net1plus.com>
2834 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2837 Correct me if I'm wrong, folks, but the way I understand it
2838 is this: Using DCACHE as initial RAM for Stack, etc, does not
2839 require any physical RAM backing up the cache. The cleverness
2840 is that the cache is being used as a temporary supply of
2841 necessary storage before the SDRAM controller is setup. It's
2842 beyond the scope of this list to expain the details, but you
2843 can see how this works by studying the cache architecture and
2844 operation in the architecture and processor-specific manuals.
2846 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2847 is another option for the system designer to use as an
2848 initial stack/ram area prior to SDRAM being available. Either
2849 option should work for you. Using CS 4 should be fine if your
2850 board designers haven't used it for something that would
2851 cause you grief during the initial boot! It is frequently not
2854 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2855 with your processor/board/system design. The default value
2856 you will find in any recent u-boot distribution in
2857 Walnut405.h should work for you. I'd set it to a value larger
2858 than your SDRAM module. If you have a 64MB SDRAM module, set
2859 it above 400_0000. Just make sure your board has no resources
2860 that are supposed to respond to that address! That code in
2861 start.S has been around a while and should work as is when
2862 you get the config right.
2867 It is essential to remember this, since it has some impact on the C
2868 code for the initialization procedures:
2870 * Initialized global data (data segment) is read-only. Do not attempt
2873 * Do not use any unitialized global data (or implicitely initialized
2874 as zero data - BSS segment) at all - this is undefined, initiali-
2875 zation is performed later (when relocating to RAM).
2877 * Stack space is very limited. Avoid big data buffers or things like
2880 Having only the stack as writable memory limits means we cannot use
2881 normal global data to share information beween the code. But it
2882 turned out that the implementation of U-Boot can be greatly
2883 simplified by making a global data structure (gd_t) available to all
2884 functions. We could pass a pointer to this data as argument to _all_
2885 functions, but this would bloat the code. Instead we use a feature of
2886 the GCC compiler (Global Register Variables) to share the data: we
2887 place a pointer (gd) to the global data into a register which we
2888 reserve for this purpose.
2890 When choosing a register for such a purpose we are restricted by the
2891 relevant (E)ABI specifications for the current architecture, and by
2892 GCC's implementation.
2894 For PowerPC, the following registers have specific use:
2897 R3-R4: parameter passing and return values
2898 R5-R10: parameter passing
2899 R13: small data area pointer
2903 (U-Boot also uses R14 as internal GOT pointer.)
2905 ==> U-Boot will use R29 to hold a pointer to the global data
2907 Note: on PPC, we could use a static initializer (since the
2908 address of the global data structure is known at compile time),
2909 but it turned out that reserving a register results in somewhat
2910 smaller code - although the code savings are not that big (on
2911 average for all boards 752 bytes for the whole U-Boot image,
2912 624 text + 127 data).
2914 On ARM, the following registers are used:
2916 R0: function argument word/integer result
2917 R1-R3: function argument word
2919 R10: stack limit (used only if stack checking if enabled)
2920 R11: argument (frame) pointer
2921 R12: temporary workspace
2924 R15: program counter
2926 ==> U-Boot will use R8 to hold a pointer to the global data
2932 U-Boot runs in system state and uses physical addresses, i.e. the
2933 MMU is not used either for address mapping nor for memory protection.
2935 The available memory is mapped to fixed addresses using the memory
2936 controller. In this process, a contiguous block is formed for each
2937 memory type (Flash, SDRAM, SRAM), even when it consists of several
2938 physical memory banks.
2940 U-Boot is installed in the first 128 kB of the first Flash bank (on
2941 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2942 booting and sizing and initializing DRAM, the code relocates itself
2943 to the upper end of DRAM. Immediately below the U-Boot code some
2944 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2945 configuration setting]. Below that, a structure with global Board
2946 Info data is placed, followed by the stack (growing downward).
2948 Additionally, some exception handler code is copied to the low 8 kB
2949 of DRAM (0x00000000 ... 0x00001FFF).
2951 So a typical memory configuration with 16 MB of DRAM could look like
2954 0x0000 0000 Exception Vector code
2957 0x0000 2000 Free for Application Use
2963 0x00FB FF20 Monitor Stack (Growing downward)
2964 0x00FB FFAC Board Info Data and permanent copy of global data
2965 0x00FC 0000 Malloc Arena
2968 0x00FE 0000 RAM Copy of Monitor Code
2969 ... eventually: LCD or video framebuffer
2970 ... eventually: pRAM (Protected RAM - unchanged by reset)
2971 0x00FF FFFF [End of RAM]
2974 System Initialization:
2975 ----------------------
2977 In the reset configuration, U-Boot starts at the reset entry point
2978 (on most PowerPC systens at address 0x00000100). Because of the reset
2979 configuration for CS0# this is a mirror of the onboard Flash memory.
2980 To be able to re-map memory U-Boot then jumps to its link address.
2981 To be able to implement the initialization code in C, a (small!)
2982 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2983 which provide such a feature like MPC8xx or MPC8260), or in a locked
2984 part of the data cache. After that, U-Boot initializes the CPU core,
2985 the caches and the SIU.
2987 Next, all (potentially) available memory banks are mapped using a
2988 preliminary mapping. For example, we put them on 512 MB boundaries
2989 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2990 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2991 programmed for SDRAM access. Using the temporary configuration, a
2992 simple memory test is run that determines the size of the SDRAM
2995 When there is more than one SDRAM bank, and the banks are of
2996 different size, the largest is mapped first. For equal size, the first
2997 bank (CS2#) is mapped first. The first mapping is always for address
2998 0x00000000, with any additional banks following immediately to create
2999 contiguous memory starting from 0.
3001 Then, the monitor installs itself at the upper end of the SDRAM area
3002 and allocates memory for use by malloc() and for the global Board
3003 Info data; also, the exception vector code is copied to the low RAM
3004 pages, and the final stack is set up.
3006 Only after this relocation will you have a "normal" C environment;
3007 until that you are restricted in several ways, mostly because you are
3008 running from ROM, and because the code will have to be relocated to a
3012 U-Boot Porting Guide:
3013 ----------------------
3015 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3019 int main (int argc, char *argv[])
3021 sighandler_t no_more_time;
3023 signal (SIGALRM, no_more_time);
3024 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3026 if (available_money > available_manpower) {
3027 pay consultant to port U-Boot;
3031 Download latest U-Boot source;
3033 Subscribe to u-boot-users mailing list;
3036 email ("Hi, I am new to U-Boot, how do I get started?");
3040 Read the README file in the top level directory;
3041 Read http://www.denx.de/re/DPLG.html
3042 Read the source, Luke;
3045 if (available_money > toLocalCurrency ($2500)) {
3048 Add a lot of aggravation and time;
3051 Create your own board support subdirectory;
3053 Create your own board config file;
3057 Add / modify source code;
3061 email ("Hi, I am having problems...");
3063 Send patch file to Wolfgang;
3068 void no_more_time (int sig)
3077 All contributions to U-Boot should conform to the Linux kernel
3078 coding style; see the file "Documentation/CodingStyle" in your Linux
3079 kernel source directory.
3081 Please note that U-Boot is implemented in C (and to some small parts
3082 in Assembler); no C++ is used, so please do not use C++ style
3083 comments (//) in your code.
3085 Submissions which do not conform to the standards may be returned
3086 with a request to reformat the changes.
3092 Since the number of patches for U-Boot is growing, we need to
3093 establish some rules. Submissions which do not conform to these rules
3094 may be rejected, even when they contain important and valuable stuff.
3097 When you send a patch, please include the following information with
3100 * For bug fixes: a description of the bug and how your patch fixes
3101 this bug. Please try to include a way of demonstrating that the
3102 patch actually fixes something.
3104 * For new features: a description of the feature and your
3107 * A CHANGELOG entry as plaintext (separate from the patch)
3109 * For major contributions, your entry to the CREDITS file
3111 * When you add support for a new board, don't forget to add this
3112 board to the MAKEALL script, too.
3114 * If your patch adds new configuration options, don't forget to
3115 document these in the README file.
3117 * The patch itself. If you are accessing the CVS repository use "cvs
3118 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3119 version of diff does not support these options, then get the latest
3120 version of GNU diff.
3122 The current directory when running this command shall be the top
3123 level directory of the U-Boot source tree, or it's parent directory
3124 (i. e. please make sure that your patch includes sufficient
3125 directory information for the affected files).
3127 We accept patches as plain text, MIME attachments or as uuencoded
3130 * If one logical set of modifications affects or creates several
3131 files, all these changes shall be submitted in a SINGLE patch file.
3133 * Changesets that contain different, unrelated modifications shall be
3134 submitted as SEPARATE patches, one patch per changeset.
3139 * Before sending the patch, run the MAKEALL script on your patched
3140 source tree and make sure that no errors or warnings are reported
3141 for any of the boards.
3143 * Keep your modifications to the necessary minimum: A patch
3144 containing several unrelated changes or arbitrary reformats will be
3145 returned with a request to re-formatting / split it.
3147 * If you modify existing code, make sure that your new code does not
3148 add to the memory footprint of the code ;-) Small is beautiful!
3149 When adding new features, these should compile conditionally only
3150 (using #ifdef), and the resulting code with the new feature
3151 disabled must not need more memory than the old code without your
projects / people / ms / u-boot.git / blob