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_TFTP_LOADADDR:
1502 Default load address for network file downloads
1504 - CFG_LOADS_BAUD_CHANGE:
1505 Enable temporary baudrate change while serial download
1508 Physical start address of SDRAM. _Must_ be 0 here.
1511 Physical start address of Motherboard I/O (if using a
1515 Physical start address of Flash memory.
1518 Physical start address of boot monitor code (set by
1519 make config files to be same as the text base address
1520 (TEXT_BASE) used when linking) - same as
1521 CFG_FLASH_BASE when booting from flash.
1524 Size of memory reserved for monitor code, used to
1525 determine _at_compile_time_ (!) if the environment is
1526 embedded within the U-Boot image, or in a separate
1530 Size of DRAM reserved for malloc() use.
1533 Maximum size of memory mapped by the startup code of
1534 the Linux kernel; all data that must be processed by
1535 the Linux kernel (bd_info, boot arguments, eventually
1536 initrd image) must be put below this limit.
1538 - CFG_MAX_FLASH_BANKS:
1539 Max number of Flash memory banks
1541 - CFG_MAX_FLASH_SECT:
1542 Max number of sectors on a Flash chip
1544 - CFG_FLASH_ERASE_TOUT:
1545 Timeout for Flash erase operations (in ms)
1547 - CFG_FLASH_WRITE_TOUT:
1548 Timeout for Flash write operations (in ms)
1550 - CFG_FLASH_LOCK_TOUT
1551 Timeout for Flash set sector lock bit operation (in ms)
1553 - CFG_FLASH_UNLOCK_TOUT
1554 Timeout for Flash clear lock bits operation (in ms)
1556 - CFG_FLASH_PROTECTION
1557 If defined, hardware flash sectors protection is used
1558 instead of U-Boot software protection.
1560 - CFG_DIRECT_FLASH_TFTP:
1562 Enable TFTP transfers directly to flash memory;
1563 without this option such a download has to be
1564 performed in two steps: (1) download to RAM, and (2)
1565 copy from RAM to flash.
1567 The two-step approach is usually more reliable, since
1568 you can check if the download worked before you erase
1569 the flash, but in some situations (when sytem RAM is
1570 too limited to allow for a tempory copy of the
1571 downloaded image) this option may be very useful.
1574 Define if the flash driver uses extra elements in the
1575 common flash structure for storing flash geometry
1577 - CFG_RX_ETH_BUFFER:
1578 Defines the number of ethernet receive buffers. On some
1579 ethernet controllers it is recommended to set this value
1580 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1581 buffers can be full shortly after enabling the interface
1582 on high ethernet traffic.
1583 Defaults to 4 if not defined.
1585 The following definitions that deal with the placement and management
1586 of environment data (variable area); in general, we support the
1587 following configurations:
1589 - CFG_ENV_IS_IN_FLASH:
1591 Define this if the environment is in flash memory.
1593 a) The environment occupies one whole flash sector, which is
1594 "embedded" in the text segment with the U-Boot code. This
1595 happens usually with "bottom boot sector" or "top boot
1596 sector" type flash chips, which have several smaller
1597 sectors at the start or the end. For instance, such a
1598 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1599 such a case you would place the environment in one of the
1600 4 kB sectors - with U-Boot code before and after it. With
1601 "top boot sector" type flash chips, you would put the
1602 environment in one of the last sectors, leaving a gap
1603 between U-Boot and the environment.
1607 Offset of environment data (variable area) to the
1608 beginning of flash memory; for instance, with bottom boot
1609 type flash chips the second sector can be used: the offset
1610 for this sector is given here.
1612 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1616 This is just another way to specify the start address of
1617 the flash sector containing the environment (instead of
1620 - CFG_ENV_SECT_SIZE:
1622 Size of the sector containing the environment.
1625 b) Sometimes flash chips have few, equal sized, BIG sectors.
1626 In such a case you don't want to spend a whole sector for
1631 If you use this in combination with CFG_ENV_IS_IN_FLASH
1632 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1633 of this flash sector for the environment. This saves
1634 memory for the RAM copy of the environment.
1636 It may also save flash memory if you decide to use this
1637 when your environment is "embedded" within U-Boot code,
1638 since then the remainder of the flash sector could be used
1639 for U-Boot code. It should be pointed out that this is
1640 STRONGLY DISCOURAGED from a robustness point of view:
1641 updating the environment in flash makes it always
1642 necessary to erase the WHOLE sector. If something goes
1643 wrong before the contents has been restored from a copy in
1644 RAM, your target system will be dead.
1646 - CFG_ENV_ADDR_REDUND
1649 These settings describe a second storage area used to hold
1650 a redundand copy of the environment data, so that there is
1651 a valid backup copy in case there is a power failure during
1652 a "saveenv" operation.
1654 BE CAREFUL! Any changes to the flash layout, and some changes to the
1655 source code will make it necessary to adapt <board>/u-boot.lds*
1659 - CFG_ENV_IS_IN_NVRAM:
1661 Define this if you have some non-volatile memory device
1662 (NVRAM, battery buffered SRAM) which you want to use for the
1668 These two #defines are used to determin the memory area you
1669 want to use for environment. It is assumed that this memory
1670 can just be read and written to, without any special
1673 BE CAREFUL! The first access to the environment happens quite early
1674 in U-Boot initalization (when we try to get the setting of for the
1675 console baudrate). You *MUST* have mappend your NVRAM area then, or
1678 Please note that even with NVRAM we still use a copy of the
1679 environment in RAM: we could work on NVRAM directly, but we want to
1680 keep settings there always unmodified except somebody uses "saveenv"
1681 to save the current settings.
1684 - CFG_ENV_IS_IN_EEPROM:
1686 Use this if you have an EEPROM or similar serial access
1687 device and a driver for it.
1692 These two #defines specify the offset and size of the
1693 environment area within the total memory of your EEPROM.
1695 - CFG_I2C_EEPROM_ADDR:
1696 If defined, specified the chip address of the EEPROM device.
1697 The default address is zero.
1699 - CFG_EEPROM_PAGE_WRITE_BITS:
1700 If defined, the number of bits used to address bytes in a
1701 single page in the EEPROM device. A 64 byte page, for example
1702 would require six bits.
1704 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1705 If defined, the number of milliseconds to delay between
1706 page writes. The default is zero milliseconds.
1708 - CFG_I2C_EEPROM_ADDR_LEN:
1709 The length in bytes of the EEPROM memory array address. Note
1710 that this is NOT the chip address length!
1713 The size in bytes of the EEPROM device.
1716 - CFG_SPI_INIT_OFFSET
1718 Defines offset to the initial SPI buffer area in DPRAM. The
1719 area is used at an early stage (ROM part) if the environment
1720 is configured to reside in the SPI EEPROM: We need a 520 byte
1721 scratch DPRAM area. It is used between the two initialization
1722 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1723 to be a good choice since it makes it far enough from the
1724 start of the data area as well as from the stack pointer.
1726 Please note that the environment is read-only as long as the monitor
1727 has been relocated to RAM and a RAM copy of the environment has been
1728 created; also, when using EEPROM you will have to use getenv_r()
1729 until then to read environment variables.
1731 The environment is protected by a CRC32 checksum. Before the monitor
1732 is relocated into RAM, as a result of a bad CRC you will be working
1733 with the compiled-in default environment - *silently*!!! [This is
1734 necessary, because the first environment variable we need is the
1735 "baudrate" setting for the console - if we have a bad CRC, we don't
1736 have any device yet where we could complain.]
1738 Note: once the monitor has been relocated, then it will complain if
1739 the default environment is used; a new CRC is computed as soon as you
1740 use the "saveenv" command to store a valid environment.
1743 Low Level (hardware related) configuration options:
1744 ---------------------------------------------------
1746 - CFG_CACHELINE_SIZE:
1747 Cache Line Size of the CPU.
1750 Default address of the IMMR after system reset.
1752 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1753 and RPXsuper) to be able to adjust the position of
1754 the IMMR register after a reset.
1756 - Floppy Disk Support:
1757 CFG_FDC_DRIVE_NUMBER
1759 the default drive number (default value 0)
1763 defines the spacing between fdc chipset registers
1768 defines the offset of register from address. It
1769 depends on which part of the data bus is connected to
1770 the fdc chipset. (default value 0)
1772 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1773 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1776 if CFG_FDC_HW_INIT is defined, then the function
1777 fdc_hw_init() is called at the beginning of the FDC
1778 setup. fdc_hw_init() must be provided by the board
1779 source code. It is used to make hardware dependant
1782 - CFG_IMMR: Physical address of the Internal Memory Mapped
1783 Register; DO NOT CHANGE! (11-4)
1784 [MPC8xx systems only]
1786 - CFG_INIT_RAM_ADDR:
1788 Start address of memory area that can be used for
1789 initial data and stack; please note that this must be
1790 writable memory that is working WITHOUT special
1791 initialization, i. e. you CANNOT use normal RAM which
1792 will become available only after programming the
1793 memory controller and running certain initialization
1796 U-Boot uses the following memory types:
1797 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1798 - MPC824X: data cache
1799 - PPC4xx: data cache
1801 - CFG_GBL_DATA_OFFSET:
1803 Offset of the initial data structure in the memory
1804 area defined by CFG_INIT_RAM_ADDR. Usually
1805 CFG_GBL_DATA_OFFSET is chosen such that the initial
1806 data is located at the end of the available space
1807 (sometimes written as (CFG_INIT_RAM_END -
1808 CFG_INIT_DATA_SIZE), and the initial stack is just
1809 below that area (growing from (CFG_INIT_RAM_ADDR +
1810 CFG_GBL_DATA_OFFSET) downward.
1813 On the MPC824X (or other systems that use the data
1814 cache for initial memory) the address chosen for
1815 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1816 point to an otherwise UNUSED address space between
1817 the top of RAM and the start of the PCI space.
1819 - CFG_SIUMCR: SIU Module Configuration (11-6)
1821 - CFG_SYPCR: System Protection Control (11-9)
1823 - CFG_TBSCR: Time Base Status and Control (11-26)
1825 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1827 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1829 - CFG_SCCR: System Clock and reset Control Register (15-27)
1831 - CFG_OR_TIMING_SDRAM:
1835 periodic timer for refresh
1837 - CFG_DER: Debug Event Register (37-47)
1839 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1840 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1841 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1843 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1845 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1846 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1847 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1848 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1850 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1851 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1852 Machine Mode Register and Memory Periodic Timer
1853 Prescaler definitions (SDRAM timing)
1855 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1856 enable I2C microcode relocation patch (MPC8xx);
1857 define relocation offset in DPRAM [DSP2]
1859 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1860 enable SPI microcode relocation patch (MPC8xx);
1861 define relocation offset in DPRAM [SCC4]
1864 Use OSCM clock mode on MBX8xx board. Be careful,
1865 wrong setting might damage your board. Read
1866 doc/README.MBX before setting this variable!
1868 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1869 Offset of the bootmode word in DPRAM used by post
1870 (Power On Self Tests). This definition overrides
1871 #define'd default value in commproc.h resp.
1874 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1875 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1876 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1877 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1878 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1879 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1880 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1881 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1882 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1884 Building the Software:
1885 ======================
1887 Building U-Boot has been tested in native PPC environments (on a
1888 PowerBook G3 running LinuxPPC 2000) and in cross environments
1889 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1892 If you are not using a native PPC environment, it is assumed that you
1893 have the GNU cross compiling tools available in your path and named
1894 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1895 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1896 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1899 CROSS_COMPILE = ppc_4xx-
1902 U-Boot is intended to be simple to build. After installing the
1903 sources you must configure U-Boot for one specific board type. This
1908 where "NAME_config" is the name of one of the existing
1909 configurations; the following names are supported:
1911 ADCIOP_config GTH_config TQM850L_config
1912 ADS860_config IP860_config TQM855L_config
1913 AR405_config IVML24_config TQM860L_config
1914 CANBT_config IVMS8_config WALNUT405_config
1915 CPCI405_config LANTEC_config cogent_common_config
1916 CPCIISER4_config MBX_config cogent_mpc8260_config
1917 CU824_config MBX860T_config cogent_mpc8xx_config
1918 ESTEEM192E_config RPXlite_config hermes_config
1919 ETX094_config RPXsuper_config hymod_config
1920 FADS823_config SM850_config lwmon_config
1921 FADS850SAR_config SPD823TS_config pcu_e_config
1922 FADS860T_config SXNI855T_config rsdproto_config
1923 FPS850L_config Sandpoint8240_config sbc8260_config
1924 GENIETV_config TQM823L_config PIP405_config
1925 GEN860T_config EBONY_config FPS860L_config
1926 ELPT860_config cmi_mpc5xx_config NETVIA_config
1927 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
1929 Note: for some board special configuration names may exist; check if
1930 additional information is available from the board vendor; for
1931 instance, the TQM8xxL systems run normally at 50 MHz and use a
1932 SCC for 10baseT ethernet; there are also systems with 80 MHz
1933 CPU clock, and an optional Fast Ethernet module is available
1934 for CPU's with FEC. You can select such additional "features"
1935 when chosing the configuration, i. e.
1938 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1940 make TQM860L_FEC_config
1941 - will configure for a TQM860L at 50MHz with FEC for ethernet
1943 make TQM860L_80MHz_config
1944 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1947 make TQM860L_FEC_80MHz_config
1948 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1950 make TQM823L_LCD_config
1951 - will configure for a TQM823L with U-Boot console on LCD
1953 make TQM823L_LCD_80MHz_config
1954 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1959 Finally, type "make all", and you should get some working U-Boot
1960 images ready for download to / installation on your system:
1962 - "u-boot.bin" is a raw binary image
1963 - "u-boot" is an image in ELF binary format
1964 - "u-boot.srec" is in Motorola S-Record format
1967 Please be aware that the Makefiles assume you are using GNU make, so
1968 for instance on NetBSD you might need to use "gmake" instead of
1972 If the system board that you have is not listed, then you will need
1973 to port U-Boot to your hardware platform. To do this, follow these
1976 1. Add a new configuration option for your board to the toplevel
1977 "Makefile" and to the "MAKEALL" script, using the existing
1978 entries as examples. Note that here and at many other places
1979 boards and other names are listed in alphabetical sort order. Please
1981 2. Create a new directory to hold your board specific code. Add any
1982 files you need. In your board directory, you will need at least
1983 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1984 3. Create a new configuration file "include/configs/<board>.h" for
1986 3. If you're porting U-Boot to a new CPU, then also create a new
1987 directory to hold your CPU specific code. Add any files you need.
1988 4. Run "make <board>_config" with your new name.
1989 5. Type "make", and you should get a working "u-boot.srec" file
1990 to be installed on your target system.
1991 6. Debug and solve any problems that might arise.
1992 [Of course, this last step is much harder than it sounds.]
1995 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1996 ==============================================================
1998 If you have modified U-Boot sources (for instance added a new board
1999 or support for new devices, a new CPU, etc.) you are expected to
2000 provide feedback to the other developers. The feedback normally takes
2001 the form of a "patch", i. e. a context diff against a certain (latest
2002 official or latest in CVS) version of U-Boot sources.
2004 But before you submit such a patch, please verify that your modifi-
2005 cation did not break existing code. At least make sure that *ALL* of
2006 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2007 just run the "MAKEALL" script, which will configure and build U-Boot
2008 for ALL supported system. Be warned, this will take a while. You can
2009 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2010 environment variable to the script, i. e. to use the cross tools from
2011 MontaVista's Hard Hat Linux you can type
2013 CROSS_COMPILE=ppc_8xx- MAKEALL
2015 or to build on a native PowerPC system you can type
2017 CROSS_COMPILE=' ' MAKEALL
2019 See also "U-Boot Porting Guide" below.
2022 Monitor Commands - Overview:
2023 ============================
2025 go - start application at address 'addr'
2026 run - run commands in an environment variable
2027 bootm - boot application image from memory
2028 bootp - boot image via network using BootP/TFTP protocol
2029 tftpboot- boot image via network using TFTP protocol
2030 and env variables "ipaddr" and "serverip"
2031 (and eventually "gatewayip")
2032 rarpboot- boot image via network using RARP/TFTP protocol
2033 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2034 loads - load S-Record file over serial line
2035 loadb - load binary file over serial line (kermit mode)
2037 mm - memory modify (auto-incrementing)
2038 nm - memory modify (constant address)
2039 mw - memory write (fill)
2041 cmp - memory compare
2042 crc32 - checksum calculation
2043 imd - i2c memory display
2044 imm - i2c memory modify (auto-incrementing)
2045 inm - i2c memory modify (constant address)
2046 imw - i2c memory write (fill)
2047 icrc32 - i2c checksum calculation
2048 iprobe - probe to discover valid I2C chip addresses
2049 iloop - infinite loop on address range
2050 isdram - print SDRAM configuration information
2051 sspi - SPI utility commands
2052 base - print or set address offset
2053 printenv- print environment variables
2054 setenv - set environment variables
2055 saveenv - save environment variables to persistent storage
2056 protect - enable or disable FLASH write protection
2057 erase - erase FLASH memory
2058 flinfo - print FLASH memory information
2059 bdinfo - print Board Info structure
2060 iminfo - print header information for application image
2061 coninfo - print console devices and informations
2062 ide - IDE sub-system
2063 loop - infinite loop on address range
2064 mtest - simple RAM test
2065 icache - enable or disable instruction cache
2066 dcache - enable or disable data cache
2067 reset - Perform RESET of the CPU
2068 echo - echo args to console
2069 version - print monitor version
2070 help - print online help
2071 ? - alias for 'help'
2074 Monitor Commands - Detailed Description:
2075 ========================================
2079 For now: just type "help <command>".
2082 Environment Variables:
2083 ======================
2085 U-Boot supports user configuration using Environment Variables which
2086 can be made persistent by saving to Flash memory.
2088 Environment Variables are set using "setenv", printed using
2089 "printenv", and saved to Flash using "saveenv". Using "setenv"
2090 without a value can be used to delete a variable from the
2091 environment. As long as you don't save the environment you are
2092 working with an in-memory copy. In case the Flash area containing the
2093 environment is erased by accident, a default environment is provided.
2095 Some configuration options can be set using Environment Variables:
2097 baudrate - see CONFIG_BAUDRATE
2099 bootdelay - see CONFIG_BOOTDELAY
2101 bootcmd - see CONFIG_BOOTCOMMAND
2103 bootargs - Boot arguments when booting an RTOS image
2105 bootfile - Name of the image to load with TFTP
2107 autoload - if set to "no" (any string beginning with 'n'),
2108 "bootp" will just load perform a lookup of the
2109 configuration from the BOOTP server, but not try to
2110 load any image using TFTP
2112 autostart - if set to "yes", an image loaded using the "bootp",
2113 "rarpboot", "tftpboot" or "diskboot" commands will
2114 be automatically started (by internally calling
2117 If set to "no", a standalone image passed to the
2118 "bootm" command will be copied to the load address
2119 (and eventually uncompressed), but NOT be started.
2120 This can be used to load and uncompress arbitrary
2123 initrd_high - restrict positioning of initrd images:
2124 If this variable is not set, initrd images will be
2125 copied to the highest possible address in RAM; this
2126 is usually what you want since it allows for
2127 maximum initrd size. If for some reason you want to
2128 make sure that the initrd image is loaded below the
2129 CFG_BOOTMAPSZ limit, you can set this environment
2130 variable to a value of "no" or "off" or "0".
2131 Alternatively, you can set it to a maximum upper
2132 address to use (U-Boot will still check that it
2133 does not overwrite the U-Boot stack and data).
2135 For instance, when you have a system with 16 MB
2136 RAM, and want to reserve 4 MB from use by Linux,
2137 you can do this by adding "mem=12M" to the value of
2138 the "bootargs" variable. However, now you must make
2139 sure that the initrd image is placed in the first
2140 12 MB as well - this can be done with
2142 setenv initrd_high 00c00000
2144 If you set initrd_high to 0xFFFFFFFF, this is an
2145 indication to U-Boot that all addresses are legal
2146 for the Linux kernel, including addresses in flash
2147 memory. In this case U-Boot will NOT COPY the
2148 ramdisk at all. This may be useful to reduce the
2149 boot time on your system, but requires that this
2150 feature is supported by your Linux kernel.
2152 ipaddr - IP address; needed for tftpboot command
2154 loadaddr - Default load address for commands like "bootp",
2155 "rarpboot", "tftpboot", "loadb" or "diskboot"
2157 loads_echo - see CONFIG_LOADS_ECHO
2159 serverip - TFTP server IP address; needed for tftpboot command
2161 bootretry - see CONFIG_BOOT_RETRY_TIME
2163 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2165 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2168 The following environment variables may be used and automatically
2169 updated by the network boot commands ("bootp" and "rarpboot"),
2170 depending the information provided by your boot server:
2172 bootfile - see above
2173 dnsip - IP address of your Domain Name Server
2174 dnsip2 - IP address of your secondary Domain Name Server
2175 gatewayip - IP address of the Gateway (Router) to use
2176 hostname - Target hostname
2178 netmask - Subnet Mask
2179 rootpath - Pathname of the root filesystem on the NFS server
2180 serverip - see above
2183 There are two special Environment Variables:
2185 serial# - contains hardware identification information such
2186 as type string and/or serial number
2187 ethaddr - Ethernet address
2189 These variables can be set only once (usually during manufacturing of
2190 the board). U-Boot refuses to delete or overwrite these variables
2191 once they have been set once.
2194 Further special Environment Variables:
2196 ver - Contains the U-Boot version string as printed
2197 with the "version" command. This variable is
2198 readonly (see CONFIG_VERSION_VARIABLE).
2201 Please note that changes to some configuration parameters may take
2202 only effect after the next boot (yes, that's just like Windoze :-).
2205 Command Line Parsing:
2206 =====================
2208 There are two different command line parsers available with U-Boot:
2209 the old "simple" one, and the much more powerful "hush" shell:
2211 Old, simple command line parser:
2212 --------------------------------
2214 - supports environment variables (through setenv / saveenv commands)
2215 - several commands on one line, separated by ';'
2216 - variable substitution using "... $(name) ..." syntax
2217 - special characters ('$', ';') can be escaped by prefixing with '\',
2219 setenv bootcmd bootm \$(address)
2220 - You can also escape text by enclosing in single apostrophes, for example:
2221 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2226 - similar to Bourne shell, with control structures like
2227 if...then...else...fi, for...do...done; while...do...done,
2228 until...do...done, ...
2229 - supports environment ("global") variables (through setenv / saveenv
2230 commands) and local shell variables (through standard shell syntax
2231 "name=value"); only environment variables can be used with "run"
2237 (1) If a command line (or an environment variable executed by a "run"
2238 command) contains several commands separated by semicolon, and
2239 one of these commands fails, then the remaining commands will be
2242 (2) If you execute several variables with one call to run (i. e.
2243 calling run with a list af variables as arguments), any failing
2244 command will cause "run" to terminate, i. e. the remaining
2245 variables are not executed.
2247 Note for Redundant Ethernet Interfaces:
2248 =======================================
2250 Some boards come with redundant ethernet interfaces; U-Boot supports
2251 such configurations and is capable of automatic selection of a
2252 "working" interface when needed. MAC assignment works as follows:
2254 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2255 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2256 "eth1addr" (=>eth1), "eth2addr", ...
2258 If the network interface stores some valid MAC address (for instance
2259 in SROM), this is used as default address if there is NO correspon-
2260 ding setting in the environment; if the corresponding environment
2261 variable is set, this overrides the settings in the card; that means:
2263 o If the SROM has a valid MAC address, and there is no address in the
2264 environment, the SROM's address is used.
2266 o If there is no valid address in the SROM, and a definition in the
2267 environment exists, then the value from the environment variable is
2270 o If both the SROM and the environment contain a MAC address, and
2271 both addresses are the same, this MAC address is used.
2273 o If both the SROM and the environment contain a MAC address, and the
2274 addresses differ, the value from the environment is used and a
2277 o If neither SROM nor the environment contain a MAC address, an error
2284 The "boot" commands of this monitor operate on "image" files which
2285 can be basicly anything, preceeded by a special header; see the
2286 definitions in include/image.h for details; basicly, the header
2287 defines the following image properties:
2289 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2290 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2291 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2292 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2293 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2294 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2295 Currently supported: PowerPC).
2296 * Compression Type (uncompressed, gzip, bzip2)
2302 The header is marked by a special Magic Number, and both the header
2303 and the data portions of the image are secured against corruption by
2310 Although U-Boot should support any OS or standalone application
2311 easily, the main focus has always been on Linux during the design of
2314 U-Boot includes many features that so far have been part of some
2315 special "boot loader" code within the Linux kernel. Also, any
2316 "initrd" images to be used are no longer part of one big Linux image;
2317 instead, kernel and "initrd" are separate images. This implementation
2318 serves several purposes:
2320 - the same features can be used for other OS or standalone
2321 applications (for instance: using compressed images to reduce the
2322 Flash memory footprint)
2324 - it becomes much easier to port new Linux kernel versions because
2325 lots of low-level, hardware dependent stuff are done by U-Boot
2327 - the same Linux kernel image can now be used with different "initrd"
2328 images; of course this also means that different kernel images can
2329 be run with the same "initrd". This makes testing easier (you don't
2330 have to build a new "zImage.initrd" Linux image when you just
2331 change a file in your "initrd"). Also, a field-upgrade of the
2332 software is easier now.
2338 Porting Linux to U-Boot based systems:
2339 ---------------------------------------
2341 U-Boot cannot save you from doing all the necessary modifications to
2342 configure the Linux device drivers for use with your target hardware
2343 (no, we don't intend to provide a full virtual machine interface to
2346 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2348 Just make sure your machine specific header file (for instance
2349 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2350 Information structure as we define in include/u-boot.h, and make
2351 sure that your definition of IMAP_ADDR uses the same value as your
2352 U-Boot configuration in CFG_IMMR.
2355 Configuring the Linux kernel:
2356 -----------------------------
2358 No specific requirements for U-Boot. Make sure you have some root
2359 device (initial ramdisk, NFS) for your target system.
2362 Building a Linux Image:
2363 -----------------------
2365 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2366 not used. If you use recent kernel source, a new build target
2367 "uImage" will exist which automatically builds an image usable by
2368 U-Boot. Most older kernels also have support for a "pImage" target,
2369 which was introduced for our predecessor project PPCBoot and uses a
2370 100% compatible format.
2379 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2380 encapsulate a compressed Linux kernel image with header information,
2381 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2383 * build a standard "vmlinux" kernel image (in ELF binary format):
2385 * convert the kernel into a raw binary image:
2387 ${CROSS_COMPILE}-objcopy -O binary \
2388 -R .note -R .comment \
2389 -S vmlinux linux.bin
2391 * compress the binary image:
2395 * package compressed binary image for U-Boot:
2397 mkimage -A ppc -O linux -T kernel -C gzip \
2398 -a 0 -e 0 -n "Linux Kernel Image" \
2399 -d linux.bin.gz uImage
2402 The "mkimage" tool can also be used to create ramdisk images for use
2403 with U-Boot, either separated from the Linux kernel image, or
2404 combined into one file. "mkimage" encapsulates the images with a 64
2405 byte header containing information about target architecture,
2406 operating system, image type, compression method, entry points, time
2407 stamp, CRC32 checksums, etc.
2409 "mkimage" can be called in two ways: to verify existing images and
2410 print the header information, or to build new images.
2412 In the first form (with "-l" option) mkimage lists the information
2413 contained in the header of an existing U-Boot image; this includes
2414 checksum verification:
2416 tools/mkimage -l image
2417 -l ==> list image header information
2419 The second form (with "-d" option) is used to build a U-Boot image
2420 from a "data file" which is used as image payload:
2422 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2423 -n name -d data_file image
2424 -A ==> set architecture to 'arch'
2425 -O ==> set operating system to 'os'
2426 -T ==> set image type to 'type'
2427 -C ==> set compression type 'comp'
2428 -a ==> set load address to 'addr' (hex)
2429 -e ==> set entry point to 'ep' (hex)
2430 -n ==> set image name to 'name'
2431 -d ==> use image data from 'datafile'
2433 Right now, all Linux kernels use the same load address (0x00000000),
2434 but the entry point address depends on the kernel version:
2436 - 2.2.x kernels have the entry point at 0x0000000C,
2437 - 2.3.x and later kernels have the entry point at 0x00000000.
2439 So a typical call to build a U-Boot image would read:
2441 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2442 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2443 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2444 > examples/uImage.TQM850L
2445 Image Name: 2.4.4 kernel for TQM850L
2446 Created: Wed Jul 19 02:34:59 2000
2447 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2448 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2449 Load Address: 0x00000000
2450 Entry Point: 0x00000000
2452 To verify the contents of the image (or check for corruption):
2454 -> tools/mkimage -l examples/uImage.TQM850L
2455 Image Name: 2.4.4 kernel for TQM850L
2456 Created: Wed Jul 19 02:34:59 2000
2457 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2458 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2459 Load Address: 0x00000000
2460 Entry Point: 0x00000000
2462 NOTE: for embedded systems where boot time is critical you can trade
2463 speed for memory and install an UNCOMPRESSED image instead: this
2464 needs more space in Flash, but boots much faster since it does not
2465 need to be uncompressed:
2467 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2468 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2469 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2470 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2471 > examples/uImage.TQM850L-uncompressed
2472 Image Name: 2.4.4 kernel for TQM850L
2473 Created: Wed Jul 19 02:34:59 2000
2474 Image Type: PowerPC Linux Kernel Image (uncompressed)
2475 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2476 Load Address: 0x00000000
2477 Entry Point: 0x00000000
2480 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2481 when your kernel is intended to use an initial ramdisk:
2483 -> tools/mkimage -n 'Simple Ramdisk Image' \
2484 > -A ppc -O linux -T ramdisk -C gzip \
2485 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2486 Image Name: Simple Ramdisk Image
2487 Created: Wed Jan 12 14:01:50 2000
2488 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2489 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2490 Load Address: 0x00000000
2491 Entry Point: 0x00000000
2494 Installing a Linux Image:
2495 -------------------------
2497 To downloading a U-Boot image over the serial (console) interface,
2498 you must convert the image to S-Record format:
2500 objcopy -I binary -O srec examples/image examples/image.srec
2502 The 'objcopy' does not understand the information in the U-Boot
2503 image header, so the resulting S-Record file will be relative to
2504 address 0x00000000. To load it to a given address, you need to
2505 specify the target address as 'offset' parameter with the 'loads'
2508 Example: install the image to address 0x40100000 (which on the
2509 TQM8xxL is in the first Flash bank):
2511 => erase 40100000 401FFFFF
2517 ## Ready for S-Record download ...
2518 ~>examples/image.srec
2519 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2521 15989 15990 15991 15992
2522 [file transfer complete]
2524 ## Start Addr = 0x00000000
2527 You can check the success of the download using the 'iminfo' command;
2528 this includes a checksum verification so you can be sure no data
2529 corruption happened:
2533 ## Checking Image at 40100000 ...
2534 Image Name: 2.2.13 for initrd on TQM850L
2535 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2536 Data Size: 335725 Bytes = 327 kB = 0 MB
2537 Load Address: 00000000
2538 Entry Point: 0000000c
2539 Verifying Checksum ... OK
2545 The "bootm" command is used to boot an application that is stored in
2546 memory (RAM or Flash). In case of a Linux kernel image, the contents
2547 of the "bootargs" environment variable is passed to the kernel as
2548 parameters. You can check and modify this variable using the
2549 "printenv" and "setenv" commands:
2552 => printenv bootargs
2553 bootargs=root=/dev/ram
2555 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2557 => printenv bootargs
2558 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2561 ## Booting Linux kernel at 40020000 ...
2562 Image Name: 2.2.13 for NFS on TQM850L
2563 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2564 Data Size: 381681 Bytes = 372 kB = 0 MB
2565 Load Address: 00000000
2566 Entry Point: 0000000c
2567 Verifying Checksum ... OK
2568 Uncompressing Kernel Image ... OK
2569 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
2570 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2571 time_init: decrementer frequency = 187500000/60
2572 Calibrating delay loop... 49.77 BogoMIPS
2573 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2576 If you want to boot a Linux kernel with initial ram disk, you pass
2577 the memory addresses of both the kernel and the initrd image (PPBCOOT
2578 format!) to the "bootm" command:
2580 => imi 40100000 40200000
2582 ## Checking Image at 40100000 ...
2583 Image Name: 2.2.13 for initrd on TQM850L
2584 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2585 Data Size: 335725 Bytes = 327 kB = 0 MB
2586 Load Address: 00000000
2587 Entry Point: 0000000c
2588 Verifying Checksum ... OK
2590 ## Checking Image at 40200000 ...
2591 Image Name: Simple Ramdisk Image
2592 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2593 Data Size: 566530 Bytes = 553 kB = 0 MB
2594 Load Address: 00000000
2595 Entry Point: 00000000
2596 Verifying Checksum ... OK
2598 => bootm 40100000 40200000
2599 ## Booting Linux kernel at 40100000 ...
2600 Image Name: 2.2.13 for initrd on TQM850L
2601 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2602 Data Size: 335725 Bytes = 327 kB = 0 MB
2603 Load Address: 00000000
2604 Entry Point: 0000000c
2605 Verifying Checksum ... OK
2606 Uncompressing Kernel Image ... OK
2607 ## Loading RAMDisk Image at 40200000 ...
2608 Image Name: Simple Ramdisk Image
2609 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2610 Data Size: 566530 Bytes = 553 kB = 0 MB
2611 Load Address: 00000000
2612 Entry Point: 00000000
2613 Verifying Checksum ... OK
2614 Loading Ramdisk ... OK
2615 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
2616 Boot arguments: root=/dev/ram
2617 time_init: decrementer frequency = 187500000/60
2618 Calibrating delay loop... 49.77 BogoMIPS
2620 RAMDISK: Compressed image found at block 0
2621 VFS: Mounted root (ext2 filesystem).
2625 More About U-Boot Image Types:
2626 ------------------------------
2628 U-Boot supports the following image types:
2630 "Standalone Programs" are directly runnable in the environment
2631 provided by U-Boot; it is expected that (if they behave
2632 well) you can continue to work in U-Boot after return from
2633 the Standalone Program.
2634 "OS Kernel Images" are usually images of some Embedded OS which
2635 will take over control completely. Usually these programs
2636 will install their own set of exception handlers, device
2637 drivers, set up the MMU, etc. - this means, that you cannot
2638 expect to re-enter U-Boot except by resetting the CPU.
2639 "RAMDisk Images" are more or less just data blocks, and their
2640 parameters (address, size) are passed to an OS kernel that is
2642 "Multi-File Images" contain several images, typically an OS
2643 (Linux) kernel image and one or more data images like
2644 RAMDisks. This construct is useful for instance when you want
2645 to boot over the network using BOOTP etc., where the boot
2646 server provides just a single image file, but you want to get
2647 for instance an OS kernel and a RAMDisk image.
2649 "Multi-File Images" start with a list of image sizes, each
2650 image size (in bytes) specified by an "uint32_t" in network
2651 byte order. This list is terminated by an "(uint32_t)0".
2652 Immediately after the terminating 0 follow the images, one by
2653 one, all aligned on "uint32_t" boundaries (size rounded up to
2654 a multiple of 4 bytes).
2656 "Firmware Images" are binary images containing firmware (like
2657 U-Boot or FPGA images) which usually will be programmed to
2660 "Script files" are command sequences that will be executed by
2661 U-Boot's command interpreter; this feature is especially
2662 useful when you configure U-Boot to use a real shell (hush)
2663 as command interpreter.
2669 One of the features of U-Boot is that you can dynamically load and
2670 run "standalone" applications, which can use some resources of
2671 U-Boot like console I/O functions or interrupt services.
2673 Two simple examples are included with the sources:
2678 'examples/hello_world.c' contains a small "Hello World" Demo
2679 application; it is automatically compiled when you build U-Boot.
2680 It's configured to run at address 0x00040004, so you can play with it
2684 ## Ready for S-Record download ...
2685 ~>examples/hello_world.srec
2686 1 2 3 4 5 6 7 8 9 10 11 ...
2687 [file transfer complete]
2689 ## Start Addr = 0x00040004
2691 => go 40004 Hello World! This is a test.
2692 ## Starting application at 0x00040004 ...
2703 Hit any key to exit ...
2705 ## Application terminated, rc = 0x0
2707 Another example, which demonstrates how to register a CPM interrupt
2708 handler with the U-Boot code, can be found in 'examples/timer.c'.
2709 Here, a CPM timer is set up to generate an interrupt every second.
2710 The interrupt service routine is trivial, just printing a '.'
2711 character, but this is just a demo program. The application can be
2712 controlled by the following keys:
2714 ? - print current values og the CPM Timer registers
2715 b - enable interrupts and start timer
2716 e - stop timer and disable interrupts
2717 q - quit application
2720 ## Ready for S-Record download ...
2721 ~>examples/timer.srec
2722 1 2 3 4 5 6 7 8 9 10 11 ...
2723 [file transfer complete]
2725 ## Start Addr = 0x00040004
2728 ## Starting application at 0x00040004 ...
2731 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2734 [q, b, e, ?] Set interval 1000000 us
2737 [q, b, e, ?] ........
2738 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2741 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2744 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2747 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2749 [q, b, e, ?] ...Stopping timer
2751 [q, b, e, ?] ## Application terminated, rc = 0x0
2757 Over time, many people have reported problems when trying to use the
2758 "minicom" terminal emulation program for serial download. I (wd)
2759 consider minicom to be broken, and recommend not to use it. Under
2760 Unix, I recommend to use C-Kermit for general purpose use (and
2761 especially for kermit binary protocol download ("loadb" command), and
2762 use "cu" for S-Record download ("loads" command).
2764 Nevertheless, if you absolutely want to use it try adding this
2765 configuration to your "File transfer protocols" section:
2767 Name Program Name U/D FullScr IO-Red. Multi
2768 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2769 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2775 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2776 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2778 Building requires a cross environment; it is known to work on
2779 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2780 need gmake since the Makefiles are not compatible with BSD make).
2781 Note that the cross-powerpc package does not install include files;
2782 attempting to build U-Boot will fail because <machine/ansi.h> is
2783 missing. This file has to be installed and patched manually:
2785 # cd /usr/pkg/cross/powerpc-netbsd/include
2787 # ln -s powerpc machine
2788 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2789 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2791 Native builds *don't* work due to incompatibilities between native
2792 and U-Boot include files.
2794 Booting assumes that (the first part of) the image booted is a
2795 stage-2 loader which in turn loads and then invokes the kernel
2796 proper. Loader sources will eventually appear in the NetBSD source
2797 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2798 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2802 Implementation Internals:
2803 =========================
2805 The following is not intended to be a complete description of every
2806 implementation detail. However, it should help to understand the
2807 inner workings of U-Boot and make it easier to port it to custom
2811 Initial Stack, Global Data:
2812 ---------------------------
2814 The implementation of U-Boot is complicated by the fact that U-Boot
2815 starts running out of ROM (flash memory), usually without access to
2816 system RAM (because the memory controller is not initialized yet).
2817 This means that we don't have writable Data or BSS segments, and BSS
2818 is not initialized as zero. To be able to get a C environment working
2819 at all, we have to allocate at least a minimal stack. Implementation
2820 options for this are defined and restricted by the CPU used: Some CPU
2821 models provide on-chip memory (like the IMMR area on MPC8xx and
2822 MPC826x processors), on others (parts of) the data cache can be
2823 locked as (mis-) used as memory, etc.
2825 Chris Hallinan posted a good summary of these issues to the
2826 u-boot-users mailing list:
2828 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2829 From: "Chris Hallinan" <clh@net1plus.com>
2830 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2833 Correct me if I'm wrong, folks, but the way I understand it
2834 is this: Using DCACHE as initial RAM for Stack, etc, does not
2835 require any physical RAM backing up the cache. The cleverness
2836 is that the cache is being used as a temporary supply of
2837 necessary storage before the SDRAM controller is setup. It's
2838 beyond the scope of this list to expain the details, but you
2839 can see how this works by studying the cache architecture and
2840 operation in the architecture and processor-specific manuals.
2842 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2843 is another option for the system designer to use as an
2844 initial stack/ram area prior to SDRAM being available. Either
2845 option should work for you. Using CS 4 should be fine if your
2846 board designers haven't used it for something that would
2847 cause you grief during the initial boot! It is frequently not
2850 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2851 with your processor/board/system design. The default value
2852 you will find in any recent u-boot distribution in
2853 Walnut405.h should work for you. I'd set it to a value larger
2854 than your SDRAM module. If you have a 64MB SDRAM module, set
2855 it above 400_0000. Just make sure your board has no resources
2856 that are supposed to respond to that address! That code in
2857 start.S has been around a while and should work as is when
2858 you get the config right.
2863 It is essential to remember this, since it has some impact on the C
2864 code for the initialization procedures:
2866 * Initialized global data (data segment) is read-only. Do not attempt
2869 * Do not use any unitialized global data (or implicitely initialized
2870 as zero data - BSS segment) at all - this is undefined, initiali-
2871 zation is performed later (when relocating to RAM).
2873 * Stack space is very limited. Avoid big data buffers or things like
2876 Having only the stack as writable memory limits means we cannot use
2877 normal global data to share information beween the code. But it
2878 turned out that the implementation of U-Boot can be greatly
2879 simplified by making a global data structure (gd_t) available to all
2880 functions. We could pass a pointer to this data as argument to _all_
2881 functions, but this would bloat the code. Instead we use a feature of
2882 the GCC compiler (Global Register Variables) to share the data: we
2883 place a pointer (gd) to the global data into a register which we
2884 reserve for this purpose.
2886 When choosing a register for such a purpose we are restricted by the
2887 relevant (E)ABI specifications for the current architecture, and by
2888 GCC's implementation.
2890 For PowerPC, the following registers have specific use:
2893 R3-R4: parameter passing and return values
2894 R5-R10: parameter passing
2895 R13: small data area pointer
2899 (U-Boot also uses R14 as internal GOT pointer.)
2901 ==> U-Boot will use R29 to hold a pointer to the global data
2903 Note: on PPC, we could use a static initializer (since the
2904 address of the global data structure is known at compile time),
2905 but it turned out that reserving a register results in somewhat
2906 smaller code - although the code savings are not that big (on
2907 average for all boards 752 bytes for the whole U-Boot image,
2908 624 text + 127 data).
2910 On ARM, the following registers are used:
2912 R0: function argument word/integer result
2913 R1-R3: function argument word
2915 R10: stack limit (used only if stack checking if enabled)
2916 R11: argument (frame) pointer
2917 R12: temporary workspace
2920 R15: program counter
2922 ==> U-Boot will use R8 to hold a pointer to the global data
2928 U-Boot runs in system state and uses physical addresses, i.e. the
2929 MMU is not used either for address mapping nor for memory protection.
2931 The available memory is mapped to fixed addresses using the memory
2932 controller. In this process, a contiguous block is formed for each
2933 memory type (Flash, SDRAM, SRAM), even when it consists of several
2934 physical memory banks.
2936 U-Boot is installed in the first 128 kB of the first Flash bank (on
2937 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2938 booting and sizing and initializing DRAM, the code relocates itself
2939 to the upper end of DRAM. Immediately below the U-Boot code some
2940 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2941 configuration setting]. Below that, a structure with global Board
2942 Info data is placed, followed by the stack (growing downward).
2944 Additionally, some exception handler code is copied to the low 8 kB
2945 of DRAM (0x00000000 ... 0x00001FFF).
2947 So a typical memory configuration with 16 MB of DRAM could look like
2950 0x0000 0000 Exception Vector code
2953 0x0000 2000 Free for Application Use
2959 0x00FB FF20 Monitor Stack (Growing downward)
2960 0x00FB FFAC Board Info Data and permanent copy of global data
2961 0x00FC 0000 Malloc Arena
2964 0x00FE 0000 RAM Copy of Monitor Code
2965 ... eventually: LCD or video framebuffer
2966 ... eventually: pRAM (Protected RAM - unchanged by reset)
2967 0x00FF FFFF [End of RAM]
2970 System Initialization:
2971 ----------------------
2973 In the reset configuration, U-Boot starts at the reset entry point
2974 (on most PowerPC systens at address 0x00000100). Because of the reset
2975 configuration for CS0# this is a mirror of the onboard Flash memory.
2976 To be able to re-map memory U-Boot then jumps to its link address.
2977 To be able to implement the initialization code in C, a (small!)
2978 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2979 which provide such a feature like MPC8xx or MPC8260), or in a locked
2980 part of the data cache. After that, U-Boot initializes the CPU core,
2981 the caches and the SIU.
2983 Next, all (potentially) available memory banks are mapped using a
2984 preliminary mapping. For example, we put them on 512 MB boundaries
2985 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2986 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2987 programmed for SDRAM access. Using the temporary configuration, a
2988 simple memory test is run that determines the size of the SDRAM
2991 When there is more than one SDRAM bank, and the banks are of
2992 different size, the largest is mapped first. For equal size, the first
2993 bank (CS2#) is mapped first. The first mapping is always for address
2994 0x00000000, with any additional banks following immediately to create
2995 contiguous memory starting from 0.
2997 Then, the monitor installs itself at the upper end of the SDRAM area
2998 and allocates memory for use by malloc() and for the global Board
2999 Info data; also, the exception vector code is copied to the low RAM
3000 pages, and the final stack is set up.
3002 Only after this relocation will you have a "normal" C environment;
3003 until that you are restricted in several ways, mostly because you are
3004 running from ROM, and because the code will have to be relocated to a
3008 U-Boot Porting Guide:
3009 ----------------------
3011 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3015 int main (int argc, char *argv[])
3017 sighandler_t no_more_time;
3019 signal (SIGALRM, no_more_time);
3020 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3022 if (available_money > available_manpower) {
3023 pay consultant to port U-Boot;
3027 Download latest U-Boot source;
3029 Subscribe to u-boot-users mailing list;
3032 email ("Hi, I am new to U-Boot, how do I get started?");
3036 Read the README file in the top level directory;
3037 Read http://www.denx.de/re/DPLG.html
3038 Read the source, Luke;
3041 if (available_money > toLocalCurrency ($2500)) {
3044 Add a lot of aggravation and time;
3047 Create your own board support subdirectory;
3049 Create your own board config file;
3053 Add / modify source code;
3057 email ("Hi, I am having problems...");
3059 Send patch file to Wolfgang;
3064 void no_more_time (int sig)
3073 All contributions to U-Boot should conform to the Linux kernel
3074 coding style; see the file "Documentation/CodingStyle" in your Linux
3075 kernel source directory.
3077 Please note that U-Boot is implemented in C (and to some small parts
3078 in Assembler); no C++ is used, so please do not use C++ style
3079 comments (//) in your code.
3081 Submissions which do not conform to the standards may be returned
3082 with a request to reformat the changes.
3088 Since the number of patches for U-Boot is growing, we need to
3089 establish some rules. Submissions which do not conform to these rules
3090 may be rejected, even when they contain important and valuable stuff.
3093 When you send a patch, please include the following information with
3096 * For bug fixes: a description of the bug and how your patch fixes
3097 this bug. Please try to include a way of demonstrating that the
3098 patch actually fixes something.
3100 * For new features: a description of the feature and your
3103 * A CHANGELOG entry as plaintext (separate from the patch)
3105 * For major contributions, your entry to the CREDITS file
3107 * When you add support for a new board, don't forget to add this
3108 board to the MAKEALL script, too.
3110 * If your patch adds new configuration options, don't forget to
3111 document these in the README file.
3113 * The patch itself. If you are accessing the CVS repository use "cvs
3114 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3115 version of diff does not support these options, then get the latest
3116 version of GNU diff.
3118 The current directory when running this command shall be the top
3119 level directory of the U-Boot source tree, or it's parent directory
3120 (i. e. please make sure that your patch includes sufficient
3121 directory information for the affected files).
3123 We accept patches as plain text, MIME attachments or as uuencoded
3126 * If one logical set of modifications affects or creates several
3127 files, all these changes shall be submitted in a SINGLE patch file.
3129 * Changesets that contain different, unrelated modifications shall be
3130 submitted as SEPARATE patches, one patch per changeset.
3135 * Before sending the patch, run the MAKEALL script on your patched
3136 source tree and make sure that no errors or warnings are reported
3137 for any of the boards.
3139 * Keep your modifications to the necessary minimum: A patch
3140 containing several unrelated changes or arbitrary reformats will be
3141 returned with a request to re-formatting / split it.
3143 * If you modify existing code, make sure that your new code does not
3144 add to the memory footprint of the code ;-) Small is beautiful!
3145 When adding new features, these should compile conditionally only
3146 (using #ifdef), and the resulting code with the new feature
3147 disabled must not need more memory than the old code without your
projects / people / ms / u-boot.git / blob