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 dependend files
123 - common Misc architecture independend functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Common 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/mpc5xx Files specific to Motorola MPC5xx CPUs
144 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
145 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
146 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
147 - cpu/ppc4xx Files specific to IBM 4xx CPUs
149 - board/LEOX/ Files specific to boards manufactured by The LEOX team
150 - board/LEOX/elpt860 Files specific to ELPT860 boards
152 Files specific to RPXClassic boards
153 - board/RPXlite Files specific to RPXlite boards
154 - board/c2mon Files specific to c2mon boards
155 - board/cmi Files specific to cmi boards
156 - board/cogent Files specific to Cogent boards
157 (need further configuration)
158 Files specific to CPCIISER4 boards
159 - board/cpu86 Files specific to CPU86 boards
160 - board/cray/ Files specific to boards manufactured by Cray
161 - board/cray/L1 Files specific to L1 boards
162 - board/cu824 Files specific to CU824 boards
163 - board/ebony Files specific to IBM Ebony board
164 - board/eric Files specific to ERIC boards
165 - board/esd/ Files specific to boards manufactured by ESD
166 - board/esd/adciop Files specific to ADCIOP boards
167 - board/esd/ar405 Files specific to AR405 boards
168 - board/esd/canbt Files specific to CANBT boards
169 - board/esd/cpci405 Files specific to CPCI405 boards
170 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
171 - board/esd/common Common files for ESD boards
172 - board/esd/dasa_sim Files specific to DASA_SIM boards
173 - board/esd/du405 Files specific to DU405 boards
174 - board/esd/ocrtc Files specific to OCRTC boards
175 - board/esd/pci405 Files specific to PCI405 boards
177 Files specific to ESTEEM192E boards
178 - board/etx094 Files specific to ETX_094 boards
180 Files specific to EVB64260 boards
181 - board/fads Files specific to FADS boards
182 - board/flagadm Files specific to FLAGADM boards
183 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
184 - board/genietv Files specific to GENIETV boards
185 - board/gth Files specific to GTH boards
186 - board/hermes Files specific to HERMES boards
187 - board/hymod Files specific to HYMOD boards
188 - board/icu862 Files specific to ICU862 boards
189 - board/ip860 Files specific to IP860 boards
191 Files specific to Interphase4539 boards
192 - board/ivm Files specific to IVMS8/IVML24 boards
193 - board/lantec Files specific to LANTEC boards
194 - board/lwmon Files specific to LWMON boards
195 - board/mbx8xx Files specific to MBX boards
197 Files specific to MMPC8260ADS boards
198 - board/mpl/ Files specific to boards manufactured by MPL
199 - board/mpl/common Common files for MPL boards
200 - board/mpl/pip405 Files specific to PIP405 boards
201 - board/mpl/mip405 Files specific to MIP405 boards
202 - board/musenki Files specific to MUSEKNI boards
203 - board/mvs1 Files specific to MVS1 boards
204 - board/nx823 Files specific to NX823 boards
205 - board/oxc Files specific to OXC boards
206 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
207 - board/pm826 Files specific to PM826 boards
209 Files specific to PPMC8260 boards
211 Files specific to RPXsuper boards
213 Files specific to RSDproto boards
215 Files specific to Sandpoint boards
216 - board/sbc8260 Files specific to SBC8260 boards
217 - board/sacsng Files specific to SACSng boards
218 - board/siemens Files specific to boards manufactured by Siemens AG
219 - board/siemens/CCM Files specific to CCM boards
220 - board/siemens/IAD210 Files specific to IAD210 boards
221 - board/siemens/SCM Files specific to SCM boards
222 - board/siemens/pcu_e Files specific to PCU_E boards
223 - board/sixnet Files specific to SIXNET boards
224 - board/spd8xx Files specific to SPD8xxTS boards
225 - board/tqm8260 Files specific to TQM8260 boards
226 - board/tqm8xx Files specific to TQM8xxL boards
227 - board/w7o Files specific to W7O boards
229 Files specific to Walnut405 boards
230 - board/westel/ Files specific to boards manufactured by Westel Wireless
231 - board/westel/amx860 Files specific to AMX860 boards
232 - board/utx8245 Files specific to UTX8245 boards
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the cpu type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one of
296 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
298 or CONFIG_MPC824X, CONFIG_MPC8260
311 - Board Type: Define exactly one of
313 PowerPC based boards:
314 ---------------------
316 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
317 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
318 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
319 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
320 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
321 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
322 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
323 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
324 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
325 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
326 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
327 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
328 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
329 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
330 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
331 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
332 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
333 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
334 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
335 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
336 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
337 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
338 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
339 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
340 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
341 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
342 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
343 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
344 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
345 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
346 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
347 CONFIG_NETVIA, CONFIG_RBC823
352 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
353 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
354 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
358 - CPU Module Type: (if CONFIG_COGENT is defined)
359 Define exactly one of
361 --- FIXME --- not tested yet:
362 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
363 CONFIG_CMA287_23, CONFIG_CMA287_50
365 - Motherboard Type: (if CONFIG_COGENT is defined)
366 Define exactly one of
367 CONFIG_CMA101, CONFIG_CMA102
369 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
370 Define one or more of
373 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
374 Define one or more of
375 CONFIG_LCD_HEARTBEAT - update a character position on
376 the lcd display every second with
379 - MPC824X Family Member (if CONFIG_MPC824X is defined)
380 Define exactly one of
381 CONFIG_MPC8240, CONFIG_MPC8245
383 - 8xx CPU Options: (if using an 8xx cpu)
384 Define one or more of
385 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
386 no 32KHz reference PIT/RTC clock
391 U-Boot stores all clock information in Hz
392 internally. For binary compatibility with older Linux
393 kernels (which expect the clocks passed in the
394 bd_info data to be in MHz) the environment variable
395 "clocks_in_mhz" can be defined so that U-Boot
396 converts clock data to MHZ before passing it to the
399 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
400 "clocks_in_mhz=1" is automatically included in the
404 Depending on board, define exactly one serial port
405 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
406 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
407 console by defining CONFIG_8xx_CONS_NONE
409 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
410 port routines must be defined elsewhere
411 (i.e. serial_init(), serial_getc(), ...)
414 Enables console device for a color framebuffer. Needs following
415 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
416 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
418 VIDEO_HW_RECTFILL graphic chip supports
421 VIDEO_HW_BITBLT graphic chip supports
422 bit-blit (cf. smiLynxEM)
423 VIDEO_VISIBLE_COLS visible pixel columns
425 VIDEO_VISIBLE_ROWS visible pixel rows
426 VIDEO_PIXEL_SIZE bytes per pixel
427 VIDEO_DATA_FORMAT graphic data format
428 (0-5, cf. cfb_console.c)
429 VIDEO_FB_ADRS framebuffer address
430 VIDEO_KBD_INIT_FCT keyboard int fct
431 (i.e. i8042_kbd_init())
432 VIDEO_TSTC_FCT test char fct
434 VIDEO_GETC_FCT get char fct
436 CONFIG_CONSOLE_CURSOR cursor drawing on/off
437 (requires blink timer
439 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
440 CONFIG_CONSOLE_TIME display time/date info in
442 (requires CFG_CMD_DATE)
443 CONFIG_VIDEO_LOGO display Linux logo in
445 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
446 linux_logo.h for logo.
447 Requires CONFIG_VIDEO_LOGO
448 CONFIG_CONSOLE_EXTRA_INFO
449 addional board info beside
452 When CONFIG_CFB_CONSOLE is defined, video console is
453 default i/o. Serial console can be forced with
454 environment 'console=serial'.
457 CONFIG_BAUDRATE - in bps
458 Select one of the baudrates listed in
459 CFG_BAUDRATE_TABLE, see below.
461 - Interrupt driven serial port input:
462 CONFIG_SERIAL_SOFTWARE_FIFO
465 Use an interrupt handler for receiving data on the
466 serial port. It also enables using hardware handshake
467 (RTS/CTS) and UART's built-in FIFO. Set the number of
468 bytes the interrupt driven input buffer should have.
470 Set to 0 to disable this feature (this is the default).
471 This will also disable hardware handshake.
473 - Console UART Number:
477 If defined internal UART1 (and not UART0) is used
478 as default U-Boot console.
480 - Boot Delay: CONFIG_BOOTDELAY - in seconds
481 Delay before automatically booting the default image;
482 set to -1 to disable autoboot.
484 See doc/README.autoboot for these options that
485 work with CONFIG_BOOTDELAY. None are required.
486 CONFIG_BOOT_RETRY_TIME
487 CONFIG_BOOT_RETRY_MIN
488 CONFIG_AUTOBOOT_KEYED
489 CONFIG_AUTOBOOT_PROMPT
490 CONFIG_AUTOBOOT_DELAY_STR
491 CONFIG_AUTOBOOT_STOP_STR
492 CONFIG_AUTOBOOT_DELAY_STR2
493 CONFIG_AUTOBOOT_STOP_STR2
494 CONFIG_ZERO_BOOTDELAY_CHECK
495 CONFIG_RESET_TO_RETRY
499 Only needed when CONFIG_BOOTDELAY is enabled;
500 define a command string that is automatically executed
501 when no character is read on the console interface
502 within "Boot Delay" after reset.
505 This can be used to pass arguments to the bootm
506 command. The value of CONFIG_BOOTARGS goes into the
507 environment value "bootargs".
509 CONFIG_RAMBOOT and CONFIG_NFSBOOT
510 The value of these goes into the environment as
511 "ramboot" and "nfsboot" respectively, and can be used
512 as a convenience, when switching between booting from
518 When this option is #defined, the existence of the
519 environment variable "preboot" will be checked
520 immediately before starting the CONFIG_BOOTDELAY
521 countdown and/or running the auto-boot command resp.
522 entering interactive mode.
524 This feature is especially useful when "preboot" is
525 automatically generated or modified. For an example
526 see the LWMON board specific code: here "preboot" is
527 modified when the user holds down a certain
528 combination of keys on the (special) keyboard when
531 - Serial Download Echo Mode:
533 If defined to 1, all characters received during a
534 serial download (using the "loads" command) are
535 echoed back. This might be needed by some terminal
536 emulations (like "cu"), but may as well just take
537 time on others. This setting #define's the initial
538 value of the "loads_echo" environment variable.
540 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
542 Select one of the baudrates listed in
543 CFG_BAUDRATE_TABLE, see below.
547 Most monitor functions can be selected (or
548 de-selected) by adjusting the definition of
549 CONFIG_COMMANDS; to select individual functions,
550 #define CONFIG_COMMANDS by "OR"ing any of the
553 #define enables commands:
554 -------------------------
555 CFG_CMD_ASKENV * ask for env variable
557 CFG_CMD_BEDBUG Include BedBug Debugger
559 CFG_CMD_CACHE icache, dcache
560 CFG_CMD_CONSOLE coninfo
561 CFG_CMD_DATE * support for RTC, date/time...
562 CFG_CMD_DHCP DHCP support
563 CFG_CMD_ECHO * echo arguments
564 CFG_CMD_EEPROM * EEPROM read/write support
565 CFG_CMD_ELF bootelf, bootvx
567 CFG_CMD_FDC * Floppy Disk Support
568 CFG_CMD_FAT FAT partition support
569 CFG_CMD_FDOS * Dos diskette Support
570 CFG_CMD_FLASH flinfo, erase, protect
571 CFG_CMD_FPGA FPGA device initialization support
572 CFG_CMD_I2C * I2C serial bus support
573 CFG_CMD_IDE * IDE harddisk support
575 CFG_CMD_IMMAP * IMMR dump support
576 CFG_CMD_IRQ * irqinfo
580 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
582 CFG_CMD_MMC MMC memory mapped support
583 CFG_CMD_MII MII utility commands
584 CFG_CMD_NET bootp, tftpboot, rarpboot
585 CFG_CMD_PCI * pciinfo
586 CFG_CMD_PCMCIA * PCMCIA support
587 CFG_CMD_REGINFO * Register dump
588 CFG_CMD_RUN run command in env variable
589 CFG_CMD_SCSI * SCSI Support
590 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
591 CFG_CMD_SPI * SPI serial bus support
592 CFG_CMD_USB * USB support
593 CFG_CMD_BSP * Board SPecific functions
594 -----------------------------------------------
597 CFG_CMD_DFL Default configuration; at the moment
598 this is includes all commands, except
599 the ones marked with "*" in the list
602 If you don't define CONFIG_COMMANDS it defaults to
603 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
604 override the default settings in the respective
607 EXAMPLE: If you want all functions except of network
608 support you can write:
610 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
613 Note: Don't enable the "icache" and "dcache" commands
614 (configuration option CFG_CMD_CACHE) unless you know
615 what you (and your U-Boot users) are doing. Data
616 cache cannot be enabled on systems like the 8xx or
617 8260 (where accesses to the IMMR region must be
618 uncached), and it cannot be disabled on all other
619 systems where we (mis-) use the data cache to hold an
620 initial stack and some data.
623 XXX - this list needs to get updated!
627 If this variable is defined, it enables watchdog
628 support. There must support in the platform specific
629 code for a watchdog. For the 8xx and 8260 CPUs, the
630 SIU Watchdog feature is enabled in the SYPCR
634 CONFIG_VERSION_VARIABLE
635 If this variable is defined, an environment variable
636 named "ver" is created by U-Boot showing the U-Boot
637 version as printed by the "version" command.
638 This variable is readonly.
642 When CFG_CMD_DATE is selected, the type of the RTC
643 has to be selected, too. Define exactly one of the
646 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
647 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
648 CONFIG_RTC_MC146818 - use MC146818 RTC
649 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
650 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
651 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
652 CONFIG_RTC_DS164x - use Dallas DS164x RTC
656 When CONFIG_TIMESTAMP is selected, the timestamp
657 (date and time) of an image is printed by image
658 commands like bootm or iminfo. This option is
659 automatically enabled when you select CFG_CMD_DATE .
662 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
663 and/or CONFIG_ISO_PARTITION
665 If IDE or SCSI support is enabled (CFG_CMD_IDE or
666 CFG_CMD_SCSI) you must configure support for at least
667 one partition type as well.
670 CONFIG_IDE_RESET_ROUTINE
672 Set this to define that instead of a reset Pin, the
673 routine ide_set_reset(int idereset) will be used.
678 Set this to enable ATAPI support.
681 At the moment only there is only support for the
682 SYM53C8XX SCSI controller; define
683 CONFIG_SCSI_SYM53C8XX to enable it.
685 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
686 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
687 CFG_SCSI_MAX_LUN] can be adjusted to define the
688 maximum numbers of LUNs, SCSI ID's and target
690 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
692 - NETWORK Support (PCI):
694 Support for Intel 8254x gigabit chips.
697 Support for Intel 82557/82559/82559ER chips.
698 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
699 write routine for first time initialisation.
702 Support for Digital 2114x chips.
703 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
704 modem chip initialisation (KS8761/QS6611).
707 Support for National dp83815 chips.
710 Support for National dp8382[01] gigabit chips.
712 - NETWORK Support (other):
714 CONFIG_DRIVER_LAN91C96
715 Support for SMSC's LAN91C96 chips.
718 Define this to hold the physical address
719 of the LAN91C96's I/O space
721 CONFIG_LAN91C96_USE_32_BIT
722 Define this to enable 32 bit addressing
725 At the moment only the UHCI host controller is
726 supported (PIP405, MIP405); define
727 CONFIG_USB_UHCI to enable it.
728 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
729 end define CONFIG_USB_STORAGE to enable the USB
732 Supported are USB Keyboards and USB Floppy drives
736 The MMC controller on the Intel PXA is supported. To
737 enable this define CONFIG_MMC. The MMC can be
738 accessed from the boot prompt by mapping the device
739 to physical memory similar to flash. Command line is
740 enabled with CFG_CMD_MMC. The MMC driver also works with
741 the FAT fs. This is enabled with CFG_CMD_FAT.
746 Define this to enable standard (PC-Style) keyboard
750 Standard PC keyboard driver with US (is default) and
751 GERMAN key layout (switch via environment 'keymap=de') support.
752 Export function i8042_kbd_init, i8042_tstc and i8042_getc
753 for cfb_console. Supports cursor blinking.
758 Define this to enable video support (for output to
763 Enable Chips & Technologies 69000 Video chip
765 CONFIG_VIDEO_SMI_LYNXEM
766 Enable Silicon Motion SMI 712/710/810 Video chip
767 Videomode are selected via environment 'videomode' with
768 standard LiLo mode numbers.
769 Following modes are supported (* is default):
771 800x600 1024x768 1280x1024
772 256 (8bit) 303* 305 307
773 65536 (16bit) 314 317 31a
774 16,7 Mill (24bit) 315 318 31b
775 (i.e. setenv videomode 317; saveenv; reset;)
777 CONFIG_VIDEO_SED13806
778 Enable Epson SED13806 driver. This driver supports 8bpp
779 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
780 or CONFIG_VIDEO_SED13806_16BPP
785 Define this to enable a custom keyboard support.
786 This simply calls drv_keyboard_init() which must be
787 defined in your board-specific files.
788 The only board using this so far is RBC823.
790 - LCD Support: CONFIG_LCD
792 Define this to enable LCD support (for output to LCD
793 display); also select one of the supported displays
794 by defining one of these:
796 CONFIG_NEC_NL6648AC33:
798 NEC NL6648AC33-18. Active, color, single scan.
800 CONFIG_NEC_NL6648BC20
802 NEC NL6648BC20-08. 6.5", 640x480.
803 Active, color, single scan.
807 Sharp 320x240. Active, color, single scan.
808 It isn't 16x9, and I am not sure what it is.
810 CONFIG_SHARP_LQ64D341
812 Sharp LQ64D341 display, 640x480.
813 Active, color, single scan.
817 HLD1045 display, 640x480.
818 Active, color, single scan.
822 Optrex CBL50840-2 NF-FW 99 22 M5
824 Hitachi LMG6912RPFC-00T
828 320x240. Black & white.
830 Normally display is black on white background; define
831 CFG_WHITE_ON_BLACK to get it inverted.
833 - Spash Screen Support: CONFIG_SPLASH_SCREEN
835 If this option is set, the environment is checked for
836 a variable "splashimage". If found, the usual display
837 of logo, copyright and system information on the LCD
838 is supressed and the BMP image at the address
839 specified in "splashimage" is loaded instead. The
840 console is redirected to the "nulldev", too. This
841 allows for a "silent" boot where a splash screen is
842 loaded very quickly after power-on.
850 Define a default value for ethernet address to use
851 for the respective ethernet interface, in case this
852 is not determined automatically.
857 Define a default value for the IP address to use for
858 the default ethernet interface, in case this is not
859 determined through e.g. bootp.
864 Defines a default value for theIP address of a TFTP
865 server to contact when using the "tftboot" command.
867 - BOOTP Recovery Mode:
868 CONFIG_BOOTP_RANDOM_DELAY
870 If you have many targets in a network that try to
871 boot using BOOTP, you may want to avoid that all
872 systems send out BOOTP requests at precisely the same
873 moment (which would happen for instance at recovery
874 from a power failure, when all systems will try to
875 boot, thus flooding the BOOTP server. Defining
876 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
877 inserted before sending out BOOTP requests. The
878 following delays are insterted then:
880 1st BOOTP request: delay 0 ... 1 sec
881 2nd BOOTP request: delay 0 ... 2 sec
882 3rd BOOTP request: delay 0 ... 4 sec
884 BOOTP requests: delay 0 ... 8 sec
886 - Status LED: CONFIG_STATUS_LED
888 Several configurations allow to display the current
889 status using a LED. For instance, the LED will blink
890 fast while running U-Boot code, stop blinking as
891 soon as a reply to a BOOTP request was received, and
892 start blinking slow once the Linux kernel is running
893 (supported by a status LED driver in the Linux
894 kernel). Defining CONFIG_STATUS_LED enables this
897 - CAN Support: CONFIG_CAN_DRIVER
899 Defining CONFIG_CAN_DRIVER enables CAN driver support
900 on those systems that support this (optional)
901 feature, like the TQM8xxL modules.
903 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
905 Enables I2C serial bus commands. If this is selected,
906 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
907 to include the appropriate I2C driver.
909 See also: common/cmd_i2c.c for a description of the
910 command line interface.
915 Selects the CPM hardware driver for I2C.
919 Use software (aka bit-banging) driver instead of CPM
920 or similar hardware support for I2C. This is configured
921 via the following defines.
925 (Optional). Any commands necessary to enable I2C
926 controller or configure ports.
930 (Only for MPC8260 CPU). The I/O port to use (the code
931 assumes both bits are on the same port). Valid values
932 are 0..3 for ports A..D.
936 The code necessary to make the I2C data line active
937 (driven). If the data line is open collector, this
942 The code necessary to make the I2C data line tri-stated
943 (inactive). If the data line is open collector, this
948 Code that returns TRUE if the I2C data line is high,
953 If <bit> is TRUE, sets the I2C data line high. If it
954 is FALSE, it clears it (low).
958 If <bit> is TRUE, sets the I2C clock line high. If it
959 is FALSE, it clears it (low).
963 This delay is invoked four times per clock cycle so this
964 controls the rate of data transfer. The data rate thus
965 is 1 / (I2C_DELAY * 4).
969 When a board is reset during an i2c bus transfer
970 chips might think that the current transfer is still
971 in progress. On some boards it is possible to access
972 the i2c SCLK line directly, either by using the
973 processor pin as a GPIO or by having a second pin
974 connected to the bus. If this option is defined a
975 custom i2c_init_board() routine in boards/xxx/board.c
976 is run early in the boot sequence.
978 - SPI Support: CONFIG_SPI
980 Enables SPI driver (so far only tested with
981 SPI EEPROM, also an instance works with Crystal A/D and
982 D/As on the SACSng board)
986 Enables extended (16-bit) SPI EEPROM addressing.
987 (symmetrical to CONFIG_I2C_X)
991 Enables a software (bit-bang) SPI driver rather than
992 using hardware support. This is a general purpose
993 driver that only requires three general I/O port pins
994 (two outputs, one input) to function. If this is
995 defined, the board configuration must define several
996 SPI configuration items (port pins to use, etc). For
997 an example, see include/configs/sacsng.h.
999 - FPGA Support: CONFIG_FPGA_COUNT
1001 Specify the number of FPGA devices to support.
1005 Used to specify the types of FPGA devices. For
1007 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1009 CFG_FPGA_PROG_FEEDBACK
1011 Enable printing of hash marks during FPGA
1016 Enable checks on FPGA configuration interface busy
1017 status by the configuration function. This option
1018 will require a board or device specific function to
1023 If defined, a function that provides delays in the
1024 FPGA configuration driver.
1026 CFG_FPGA_CHECK_CTRLC
1028 Allow Control-C to interrupt FPGA configuration
1030 CFG_FPGA_CHECK_ERROR
1032 Check for configuration errors during FPGA bitfile
1033 loading. For example, abort during Virtex II
1034 configuration if the INIT_B line goes low (which
1035 indicated a CRC error).
1039 Maximum time to wait for the INIT_B line to deassert
1040 after PROB_B has been deasserted during a Virtex II
1041 FPGA configuration sequence. The default time is 500 mS.
1045 Maximum time to wait for BUSY to deassert during
1046 Virtex II FPGA configuration. The default is 5 mS.
1048 CFG_FPGA_WAIT_CONFIG
1050 Time to wait after FPGA configuration. The default is
1053 - FPGA Support: CONFIG_FPGA_COUNT
1055 Specify the number of FPGA devices to support.
1059 Used to specify the types of FPGA devices. For example,
1060 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1062 CFG_FPGA_PROG_FEEDBACK
1064 Enable printing of hash marks during FPGA configuration.
1068 Enable checks on FPGA configuration interface busy
1069 status by the configuration function. This option
1070 will require a board or device specific function to
1075 If defined, a function that provides delays in the FPGA
1076 configuration driver.
1078 CFG_FPGA_CHECK_CTRLC
1079 Allow Control-C to interrupt FPGA configuration
1081 CFG_FPGA_CHECK_ERROR
1083 Check for configuration errors during FPGA bitfile
1084 loading. For example, abort during Virtex II
1085 configuration if the INIT_B line goes low (which
1086 indicated a CRC error).
1090 Maximum time to wait for the INIT_B line to deassert
1091 after PROB_B has been deasserted during a Virtex II
1092 FPGA configuration sequence. The default time is 500
1097 Maximum time to wait for BUSY to deassert during
1098 Virtex II FPGA configuration. The default is 5 mS.
1100 CFG_FPGA_WAIT_CONFIG
1102 Time to wait after FPGA configuration. The default is
1105 - Configuration Management:
1108 If defined, this string will be added to the U-Boot
1109 version information (U_BOOT_VERSION)
1111 - Vendor Parameter Protection:
1113 U-Boot considers the values of the environment
1114 variables "serial#" (Board Serial Number) and
1115 "ethaddr" (Ethernet Address) to bb parameters that
1116 are set once by the board vendor / manufacturer, and
1117 protects these variables from casual modification by
1118 the user. Once set, these variables are read-only,
1119 and write or delete attempts are rejected. You can
1120 change this behviour:
1122 If CONFIG_ENV_OVERWRITE is #defined in your config
1123 file, the write protection for vendor parameters is
1124 completely disabled. Anybody can change or delete
1127 Alternatively, if you #define _both_ CONFIG_ETHADDR
1128 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1129 ethernet address is installed in the environment,
1130 which can be changed exactly ONCE by the user. [The
1131 serial# is unaffected by this, i. e. it remains
1137 Define this variable to enable the reservation of
1138 "protected RAM", i. e. RAM which is not overwritten
1139 by U-Boot. Define CONFIG_PRAM to hold the number of
1140 kB you want to reserve for pRAM. You can overwrite
1141 this default value by defining an environment
1142 variable "pram" to the number of kB you want to
1143 reserve. Note that the board info structure will
1144 still show the full amount of RAM. If pRAM is
1145 reserved, a new environment variable "mem" will
1146 automatically be defined to hold the amount of
1147 remaining RAM in a form that can be passed as boot
1148 argument to Linux, for instance like that:
1150 setenv bootargs ... mem=\$(mem)
1153 This way you can tell Linux not to use this memory,
1154 either, which results in a memory region that will
1155 not be affected by reboots.
1157 *WARNING* If your board configuration uses automatic
1158 detection of the RAM size, you must make sure that
1159 this memory test is non-destructive. So far, the
1160 following board configurations are known to be
1163 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1164 HERMES, IP860, RPXlite, LWMON, LANTEC,
1165 PCU_E, FLAGADM, TQM8260
1170 Define this variable to stop the system in case of a
1171 fatal error, so that you have to reset it manually.
1172 This is probably NOT a good idea for an embedded
1173 system where you want to system to reboot
1174 automatically as fast as possible, but it may be
1175 useful during development since you can try to debug
1176 the conditions that lead to the situation.
1178 CONFIG_NET_RETRY_COUNT
1180 This variable defines the number of retries for
1181 network operations like ARP, RARP, TFTP, or BOOTP
1182 before giving up the operation. If not defined, a
1183 default value of 5 is used.
1185 - Command Interpreter:
1188 Define this variable to enable the "hush" shell (from
1189 Busybox) as command line interpreter, thus enabling
1190 powerful command line syntax like
1191 if...then...else...fi conditionals or `&&' and '||'
1192 constructs ("shell scripts").
1194 If undefined, you get the old, much simpler behaviour
1195 with a somewhat smaller memory footprint.
1200 This defines the secondary prompt string, which is
1201 printed when the command interpreter needs more input
1202 to complete a command. Usually "> ".
1206 In the current implementation, the local variables
1207 space and global environment variables space are
1208 separated. Local variables are those you define by
1209 simply typing `name=value'. To access a local
1210 variable later on, you have write `$name' or
1211 `${name}'; to execute the contents of a variable
1212 directly type `$name' at the command prompt.
1214 Global environment variables are those you use
1215 setenv/printenv to work with. To run a command stored
1216 in such a variable, you need to use the run command,
1217 and you must not use the '$' sign to access them.
1219 To store commands and special characters in a
1220 variable, please use double quotation marks
1221 surrounding the whole text of the variable, instead
1222 of the backslashes before semicolons and special
1225 - Default Environment
1226 CONFIG_EXTRA_ENV_SETTINGS
1228 Define this to contain any number of null terminated
1229 strings (variable = value pairs) that will be part of
1230 the default enviroment compiled into the boot image.
1232 For example, place something like this in your
1233 board's config file:
1235 #define CONFIG_EXTRA_ENV_SETTINGS \
1239 Warning: This method is based on knowledge about the
1240 internal format how the environment is stored by the
1241 U-Boot code. This is NOT an official, exported
1242 interface! Although it is unlikely that this format
1243 will change soon, but there is no guarantee either.
1244 You better know what you are doing here.
1246 Note: overly (ab)use of the default environment is
1247 discouraged. Make sure to check other ways to preset
1248 the environment like the autoscript function or the
1251 - Show boot progress
1252 CONFIG_SHOW_BOOT_PROGRESS
1254 Defining this option allows to add some board-
1255 specific code (calling a user-provided function
1256 "show_boot_progress(int)") that enables you to show
1257 the system's boot progress on some display (for
1258 example, some LED's) on your board. At the moment,
1259 the following checkpoints are implemented:
1262 1 common/cmd_bootm.c before attempting to boot an image
1263 -1 common/cmd_bootm.c Image header has bad magic number
1264 2 common/cmd_bootm.c Image header has correct magic number
1265 -2 common/cmd_bootm.c Image header has bad checksum
1266 3 common/cmd_bootm.c Image header has correct checksum
1267 -3 common/cmd_bootm.c Image data has bad checksum
1268 4 common/cmd_bootm.c Image data has correct checksum
1269 -4 common/cmd_bootm.c Image is for unsupported architecture
1270 5 common/cmd_bootm.c Architecture check OK
1271 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1272 6 common/cmd_bootm.c Image Type check OK
1273 -6 common/cmd_bootm.c gunzip uncompression error
1274 -7 common/cmd_bootm.c Unimplemented compression type
1275 7 common/cmd_bootm.c Uncompression OK
1276 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1277 8 common/cmd_bootm.c Image Type check OK
1278 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1279 9 common/cmd_bootm.c Start initial ramdisk verification
1280 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1281 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1282 10 common/cmd_bootm.c Ramdisk header is OK
1283 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1284 11 common/cmd_bootm.c Ramdisk data has correct checksum
1285 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1286 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1287 13 common/cmd_bootm.c Start multifile image verification
1288 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1289 15 common/cmd_bootm.c All preparation done, transferring control to OS
1291 -1 common/cmd_doc.c Bad usage of "doc" command
1292 -1 common/cmd_doc.c No boot device
1293 -1 common/cmd_doc.c Unknown Chip ID on boot device
1294 -1 common/cmd_doc.c Read Error on boot device
1295 -1 common/cmd_doc.c Image header has bad magic number
1297 -1 common/cmd_ide.c Bad usage of "ide" command
1298 -1 common/cmd_ide.c No boot device
1299 -1 common/cmd_ide.c Unknown boot device
1300 -1 common/cmd_ide.c Unknown partition table
1301 -1 common/cmd_ide.c Invalid partition type
1302 -1 common/cmd_ide.c Read Error on boot device
1303 -1 common/cmd_ide.c Image header has bad magic number
1305 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1311 [so far only for SMDK2400 and TRAB boards]
1313 - Modem support endable:
1314 CONFIG_MODEM_SUPPORT
1316 - RTS/CTS Flow control enable:
1319 - Modem debug support:
1320 CONFIG_MODEM_SUPPORT_DEBUG
1322 Enables debugging stuff (char screen[1024], dbg())
1323 for modem support. Useful only with BDI2000.
1327 In the target system modem support is enabled when a
1328 specific key (key combination) is pressed during
1329 power-on. Otherwise U-Boot will boot normally
1330 (autoboot). The key_pressed() fuction is called from
1331 board_init(). Currently key_pressed() is a dummy
1332 function, returning 1 and thus enabling modem
1335 If there are no modem init strings in the
1336 environment, U-Boot proceed to autoboot; the
1337 previous output (banner, info printfs) will be
1340 See also: doc/README.Modem
1345 Configuration Settings:
1346 -----------------------
1348 - CFG_LONGHELP: Defined when you want long help messages included;
1349 undefine this when you're short of memory.
1351 - CFG_PROMPT: This is what U-Boot prints on the console to
1352 prompt for user input.
1354 - CFG_CBSIZE: Buffer size for input from the Console
1356 - CFG_PBSIZE: Buffer size for Console output
1358 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1360 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1361 the application (usually a Linux kernel) when it is
1364 - CFG_BAUDRATE_TABLE:
1365 List of legal baudrate settings for this board.
1367 - CFG_CONSOLE_INFO_QUIET
1368 Suppress display of console information at boot.
1370 - CFG_CONSOLE_IS_IN_ENV
1371 If the board specific function
1372 extern int overwrite_console (void);
1373 returns 1, the stdin, stderr and stdout are switched to the
1374 serial port, else the settings in the environment are used.
1376 - CFG_CONSOLE_OVERWRITE_ROUTINE
1377 Enable the call to overwrite_console().
1379 - CFG_CONSOLE_ENV_OVERWRITE
1380 Enable overwrite of previous console environment settings.
1382 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1383 Begin and End addresses of the area used by the
1387 Enable an alternate, more extensive memory test.
1389 - CFG_TFTP_LOADADDR:
1390 Default load address for network file downloads
1392 - CFG_LOADS_BAUD_CHANGE:
1393 Enable temporary baudrate change while serial download
1396 Physical start address of SDRAM. _Must_ be 0 here.
1399 Physical start address of Motherboard I/O (if using a
1403 Physical start address of Flash memory.
1406 Physical start address of boot monitor code (set by
1407 make config files to be same as the text base address
1408 (TEXT_BASE) used when linking) - same as
1409 CFG_FLASH_BASE when booting from flash.
1412 Size of memory reserved for monitor code, used to
1413 determine _at_compile_time_ (!) if the environment is
1414 embedded within the U-Boot image, or in a separate
1418 Size of DRAM reserved for malloc() use.
1421 Maximum size of memory mapped by the startup code of
1422 the Linux kernel; all data that must be processed by
1423 the Linux kernel (bd_info, boot arguments, eventually
1424 initrd image) must be put below this limit.
1426 - CFG_MAX_FLASH_BANKS:
1427 Max number of Flash memory banks
1429 - CFG_MAX_FLASH_SECT:
1430 Max number of sectors on a Flash chip
1432 - CFG_FLASH_ERASE_TOUT:
1433 Timeout for Flash erase operations (in ms)
1435 - CFG_FLASH_WRITE_TOUT:
1436 Timeout for Flash write operations (in ms)
1438 - CFG_DIRECT_FLASH_TFTP:
1440 Enable TFTP transfers directly to flash memory;
1441 without this option such a download has to be
1442 performed in two steps: (1) download to RAM, and (2)
1443 copy from RAM to flash.
1445 The two-step approach is usually more reliable, since
1446 you can check if the download worked before you erase
1447 the flash, but in some situations (when sytem RAM is
1448 too limited to allow for a tempory copy of the
1449 downloaded image) this option may be very useful.
1452 Define if the flash driver uses extra elements in the
1453 common flash structure for storing flash geometry
1455 - CFG_RX_ETH_BUFFER:
1456 Defines the number of ethernet receive buffers. On some
1457 ethernet controllers it is recommended to set this value
1458 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1459 buffers can be full shortly after enabling the interface
1460 on high ethernet traffic.
1461 Defaults to 4 if not defined.
1463 The following definitions that deal with the placement and management
1464 of environment data (variable area); in general, we support the
1465 following configurations:
1467 - CFG_ENV_IS_IN_FLASH:
1469 Define this if the environment is in flash memory.
1471 a) The environment occupies one whole flash sector, which is
1472 "embedded" in the text segment with the U-Boot code. This
1473 happens usually with "bottom boot sector" or "top boot
1474 sector" type flash chips, which have several smaller
1475 sectors at the start or the end. For instance, such a
1476 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1477 such a case you would place the environment in one of the
1478 4 kB sectors - with U-Boot code before and after it. With
1479 "top boot sector" type flash chips, you would put the
1480 environment in one of the last sectors, leaving a gap
1481 between U-Boot and the environment.
1485 Offset of environment data (variable area) to the
1486 beginning of flash memory; for instance, with bottom boot
1487 type flash chips the second sector can be used: the offset
1488 for this sector is given here.
1490 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1494 This is just another way to specify the start address of
1495 the flash sector containing the environment (instead of
1498 - CFG_ENV_SECT_SIZE:
1500 Size of the sector containing the environment.
1503 b) Sometimes flash chips have few, equal sized, BIG sectors.
1504 In such a case you don't want to spend a whole sector for
1509 If you use this in combination with CFG_ENV_IS_IN_FLASH
1510 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1511 of this flash sector for the environment. This saves
1512 memory for the RAM copy of the environment.
1514 It may also save flash memory if you decide to use this
1515 when your environment is "embedded" within U-Boot code,
1516 since then the remainder of the flash sector could be used
1517 for U-Boot code. It should be pointed out that this is
1518 STRONGLY DISCOURAGED from a robustness point of view:
1519 updating the environment in flash makes it always
1520 necessary to erase the WHOLE sector. If something goes
1521 wrong before the contents has been restored from a copy in
1522 RAM, your target system will be dead.
1524 - CFG_ENV_ADDR_REDUND
1527 These settings describe a second storage area used to hold
1528 a redundand copy of the environment data, so that there is
1529 a valid backup copy in case there is a power failure during
1530 a "saveenv" operation.
1532 BE CAREFUL! Any changes to the flash layout, and some changes to the
1533 source code will make it necessary to adapt <board>/u-boot.lds*
1537 - CFG_ENV_IS_IN_NVRAM:
1539 Define this if you have some non-volatile memory device
1540 (NVRAM, battery buffered SRAM) which you want to use for the
1546 These two #defines are used to determin the memory area you
1547 want to use for environment. It is assumed that this memory
1548 can just be read and written to, without any special
1551 BE CAREFUL! The first access to the environment happens quite early
1552 in U-Boot initalization (when we try to get the setting of for the
1553 console baudrate). You *MUST* have mappend your NVRAM area then, or
1556 Please note that even with NVRAM we still use a copy of the
1557 environment in RAM: we could work on NVRAM directly, but we want to
1558 keep settings there always unmodified except somebody uses "saveenv"
1559 to save the current settings.
1562 - CFG_ENV_IS_IN_EEPROM:
1564 Use this if you have an EEPROM or similar serial access
1565 device and a driver for it.
1570 These two #defines specify the offset and size of the
1571 environment area within the total memory of your EEPROM.
1573 - CFG_I2C_EEPROM_ADDR:
1574 If defined, specified the chip address of the EEPROM device.
1575 The default address is zero.
1577 - CFG_EEPROM_PAGE_WRITE_BITS:
1578 If defined, the number of bits used to address bytes in a
1579 single page in the EEPROM device. A 64 byte page, for example
1580 would require six bits.
1582 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1583 If defined, the number of milliseconds to delay between
1584 page writes. The default is zero milliseconds.
1586 - CFG_I2C_EEPROM_ADDR_LEN:
1587 The length in bytes of the EEPROM memory array address. Note
1588 that this is NOT the chip address length!
1591 The size in bytes of the EEPROM device.
1594 - CFG_SPI_INIT_OFFSET
1596 Defines offset to the initial SPI buffer area in DPRAM. The
1597 area is used at an early stage (ROM part) if the environment
1598 is configured to reside in the SPI EEPROM: We need a 520 byte
1599 scratch DPRAM area. It is used between the two initialization
1600 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1601 to be a good choice since it makes it far enough from the
1602 start of the data area as well as from the stack pointer.
1604 Please note that the environment is read-only as long as the monitor
1605 has been relocated to RAM and a RAM copy of the environment has been
1606 created; also, when using EEPROM you will have to use getenv_r()
1607 until then to read environment variables.
1609 The environment is protected by a CRC32 checksum. Before the monitor
1610 is relocated into RAM, as a result of a bad CRC you will be working
1611 with the compiled-in default environment - *silently*!!! [This is
1612 necessary, because the first environment variable we need is the
1613 "baudrate" setting for the console - if we have a bad CRC, we don't
1614 have any device yet where we could complain.]
1616 Note: once the monitor has been relocated, then it will complain if
1617 the default environment is used; a new CRC is computed as soon as you
1618 use the "saveenv" command to store a valid environment.
1621 Low Level (hardware related) configuration options:
1622 ---------------------------------------------------
1624 - CFG_CACHELINE_SIZE:
1625 Cache Line Size of the CPU.
1628 Default address of the IMMR after system reset.
1629 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1630 to be able to adjust the position of the IMMR
1631 register after a reset.
1633 - Floppy Disk Support:
1634 CFG_FDC_DRIVE_NUMBER
1636 the default drive number (default value 0)
1640 defines the spacing between fdc chipset registers
1645 defines the offset of register from address. It
1646 depends on which part of the data bus is connected to
1647 the fdc chipset. (default value 0)
1649 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1650 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1653 if CFG_FDC_HW_INIT is defined, then the function
1654 fdc_hw_init() is called at the beginning of the FDC
1655 setup. fdc_hw_init() must be provided by the board
1656 source code. It is used to make hardware dependant
1659 - CFG_IMMR: Physical address of the Internal Memory Mapped
1660 Register; DO NOT CHANGE! (11-4)
1661 [MPC8xx systems only]
1663 - CFG_INIT_RAM_ADDR:
1665 Start address of memory area tha can be used for
1666 initial data and stack; please note that this must be
1667 writable memory that is working WITHOUT special
1668 initialization, i. e. you CANNOT use normal RAM which
1669 will become available only after programming the
1670 memory controller and running certain initialization
1673 U-Boot uses the following memory types:
1674 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1675 - MPC824X: data cache
1676 - PPC4xx: data cache
1678 - CFG_GBL_DATA_OFFSET:
1680 Offset of the initial data structure in the memory
1681 area defined by CFG_INIT_RAM_ADDR. Usually
1682 CFG_GBL_DATA_OFFSET is chosen such that the initial
1683 data is located at the end of the available space
1684 (sometimes written as (CFG_INIT_RAM_END -
1685 CFG_INIT_DATA_SIZE), and the initial stack is just
1686 below that area (growing from (CFG_INIT_RAM_ADDR +
1687 CFG_GBL_DATA_OFFSET) downward.
1690 On the MPC824X (or other systems that use the data
1691 cache for initial memory) the address chosen for
1692 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1693 point to an otherwise UNUSED address space between
1694 the top of RAM and the start of the PCI space.
1696 - CFG_SIUMCR: SIU Module Configuration (11-6)
1698 - CFG_SYPCR: System Protection Control (11-9)
1700 - CFG_TBSCR: Time Base Status and Control (11-26)
1702 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1704 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1706 - CFG_SCCR: System Clock and reset Control Register (15-27)
1708 - CFG_OR_TIMING_SDRAM:
1712 periodic timer for refresh
1714 - CFG_DER: Debug Event Register (37-47)
1716 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1717 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1718 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1720 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1722 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1723 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1724 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1725 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1727 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1728 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1729 Machine Mode Register and Memory Periodic Timer
1730 Prescaler definitions (SDRAM timing)
1732 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1733 enable I2C microcode relocation patch (MPC8xx);
1734 define relocation offset in DPRAM [DSP2]
1736 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1737 enable SPI microcode relocation patch (MPC8xx);
1738 define relocation offset in DPRAM [SCC4]
1741 Use OSCM clock mode on MBX8xx board. Be careful,
1742 wrong setting might damage your board. Read
1743 doc/README.MBX before setting this variable!
1745 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1746 Offset of the bootmode word in DPRAM used by post
1747 (Power On Self Tests). This definition overrides
1748 #define'd default value in commproc.h resp.
1751 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1752 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1753 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1754 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1755 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1756 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1757 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1758 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1759 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1761 Building the Software:
1762 ======================
1764 Building U-Boot has been tested in native PPC environments (on a
1765 PowerBook G3 running LinuxPPC 2000) and in cross environments
1766 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1769 If you are not using a native PPC environment, it is assumed that you
1770 have the GNU cross compiling tools available in your path and named
1771 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1772 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1773 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1776 CROSS_COMPILE = ppc_4xx-
1779 U-Boot is intended to be simple to build. After installing the
1780 sources you must configure U-Boot for one specific board type. This
1785 where "NAME_config" is the name of one of the existing
1786 configurations; the following names are supported:
1788 ADCIOP_config GTH_config TQM850L_config
1789 ADS860_config IP860_config TQM855L_config
1790 AR405_config IVML24_config TQM860L_config
1791 CANBT_config IVMS8_config WALNUT405_config
1792 CPCI405_config LANTEC_config cogent_common_config
1793 CPCIISER4_config MBX_config cogent_mpc8260_config
1794 CU824_config MBX860T_config cogent_mpc8xx_config
1795 ESTEEM192E_config RPXlite_config hermes_config
1796 ETX094_config RPXsuper_config hymod_config
1797 FADS823_config SM850_config lwmon_config
1798 FADS850SAR_config SPD823TS_config pcu_e_config
1799 FADS860T_config SXNI855T_config rsdproto_config
1800 FPS850L_config Sandpoint8240_config sbc8260_config
1801 GENIETV_config TQM823L_config PIP405_config
1802 GEN860T_config EBONY_config FPS860L_config
1803 ELPT860_config cmi_mpc5xx_config NETVIA_config
1805 Note: for some board special configuration names may exist; check if
1806 additional information is available from the board vendor; for
1807 instance, the TQM8xxL systems run normally at 50 MHz and use a
1808 SCC for 10baseT ethernet; there are also systems with 80 MHz
1809 CPU clock, and an optional Fast Ethernet module is available
1810 for CPU's with FEC. You can select such additional "features"
1811 when chosing the configuration, i. e.
1814 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1816 make TQM860L_FEC_config
1817 - will configure for a TQM860L at 50MHz with FEC for ethernet
1819 make TQM860L_80MHz_config
1820 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1823 make TQM860L_FEC_80MHz_config
1824 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1826 make TQM823L_LCD_config
1827 - will configure for a TQM823L with U-Boot console on LCD
1829 make TQM823L_LCD_80MHz_config
1830 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1836 Finally, type "make all", and you should get some working U-Boot
1837 images ready for downlod to / installation on your system:
1839 - "u-boot.bin" is a raw binary image
1840 - "u-boot" is an image in ELF binary format
1841 - "u-boot.srec" is in Motorola S-Record format
1844 Please be aware that the Makefiles assume you are using GNU make, so
1845 for instance on NetBSD you might need to use "gmake" instead of
1849 If the system board that you have is not listed, then you will need
1850 to port U-Boot to your hardware platform. To do this, follow these
1853 1. Add a new configuration option for your board to the toplevel
1854 "Makefile" and to the "MAKEALL" script, using the existing
1855 entries as examples. Note that here and at many other places
1856 boards and other names are listed alphabetically sorted. Please
1858 2. Create a new directory to hold your board specific code. Add any
1859 files you need. In your board directory, you will need at least
1860 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1861 3. Create a new configuration file "include/configs/<board>.h" for
1863 3. If you're porting U-Boot to a new CPU, then also create a new
1864 directory to hold your CPU specific code. Add any files you need.
1865 4. Run "make <board>_config" with your new name.
1866 5. Type "make", and you should get a working "u-boot.srec" file
1867 to be installed on your target system.
1868 6. Debug and solve any problems that might arise.
1869 [Of course, this last step is much harder than it sounds.]
1872 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1873 ==============================================================
1875 If you have modified U-Boot sources (for instance added a new board
1876 or support for new devices, a new CPU, etc.) you are expected to
1877 provide feedback to the other developers. The feedback normally takes
1878 the form of a "patch", i. e. a context diff against a certain (latest
1879 official or latest in CVS) version of U-Boot sources.
1881 But before you submit such a patch, please verify that your modifi-
1882 cation did not break existing code. At least make sure that *ALL* of
1883 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1884 just run the "MAKEALL" script, which will configure and build U-Boot
1885 for ALL supported system. Be warned, this will take a while. You can
1886 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1887 environment variable to the script, i. e. to use the cross tools from
1888 MontaVista's Hard Hat Linux you can type
1890 CROSS_COMPILE=ppc_8xx- MAKEALL
1892 or to build on a native PowerPC system you can type
1894 CROSS_COMPILE=' ' MAKEALL
1896 See also "U-Boot Porting Guide" below.
1900 Monitor Commands - Overview:
1901 ============================
1903 go - start application at address 'addr'
1904 run - run commands in an environment variable
1905 bootm - boot application image from memory
1906 bootp - boot image via network using BootP/TFTP protocol
1907 tftpboot- boot image via network using TFTP protocol
1908 and env variables "ipaddr" and "serverip"
1909 (and eventually "gatewayip")
1910 rarpboot- boot image via network using RARP/TFTP protocol
1911 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1912 loads - load S-Record file over serial line
1913 loadb - load binary file over serial line (kermit mode)
1915 mm - memory modify (auto-incrementing)
1916 nm - memory modify (constant address)
1917 mw - memory write (fill)
1919 cmp - memory compare
1920 crc32 - checksum calculation
1921 imd - i2c memory display
1922 imm - i2c memory modify (auto-incrementing)
1923 inm - i2c memory modify (constant address)
1924 imw - i2c memory write (fill)
1925 icrc32 - i2c checksum calculation
1926 iprobe - probe to discover valid I2C chip addresses
1927 iloop - infinite loop on address range
1928 isdram - print SDRAM configuration information
1929 sspi - SPI utility commands
1930 base - print or set address offset
1931 printenv- print environment variables
1932 setenv - set environment variables
1933 saveenv - save environment variables to persistent storage
1934 protect - enable or disable FLASH write protection
1935 erase - erase FLASH memory
1936 flinfo - print FLASH memory information
1937 bdinfo - print Board Info structure
1938 iminfo - print header information for application image
1939 coninfo - print console devices and informations
1940 ide - IDE sub-system
1941 loop - infinite loop on address range
1942 mtest - simple RAM test
1943 icache - enable or disable instruction cache
1944 dcache - enable or disable data cache
1945 reset - Perform RESET of the CPU
1946 echo - echo args to console
1947 version - print monitor version
1948 help - print online help
1949 ? - alias for 'help'
1952 Monitor Commands - Detailed Description:
1953 ========================================
1957 For now: just type "help <command>".
1960 Environment Variables:
1961 ======================
1963 U-Boot supports user configuration using Environment Variables which
1964 can be made persistent by saving to Flash memory.
1966 Environment Variables are set using "setenv", printed using
1967 "printenv", and saved to Flash using "saveenv". Using "setenv"
1968 without a value can be used to delete a variable from the
1969 environment. As long as you don't save the environment you are
1970 working with an in-memory copy. In case the Flash area containing the
1971 environment is erased by accident, a default environment is provided.
1973 Some configuration options can be set using Environment Variables:
1975 baudrate - see CONFIG_BAUDRATE
1977 bootdelay - see CONFIG_BOOTDELAY
1979 bootcmd - see CONFIG_BOOTCOMMAND
1981 bootargs - Boot arguments when booting an RTOS image
1983 bootfile - Name of the image to load with TFTP
1985 autoload - if set to "no" (any string beginning with 'n'),
1986 "bootp" will just load perform a lookup of the
1987 configuration from the BOOTP server, but not try to
1988 load any image using TFTP
1990 autostart - if set to "yes", an image loaded using the "bootp",
1991 "rarpboot", "tftpboot" or "diskboot" commands will
1992 be automatically started (by internally calling
1995 If set to "no", a standalone image passed to the
1996 "bootm" command will be copied to the load address
1997 (and eventually uncompressed), but NOT be started.
1998 This can be used to load and uncompress arbitrary
2001 initrd_high - restrict positioning of initrd images:
2002 If this variable is not set, initrd images will be
2003 copied to the highest possible address in RAM; this
2004 is usually what you want since it allows for
2005 maximum initrd size. If for some reason you want to
2006 make sure that the initrd image is loaded below the
2007 CFG_BOOTMAPSZ limit, you can set this environment
2008 variable to a value of "no" or "off" or "0".
2009 Alternatively, you can set it to a maximum upper
2010 address to use (U-Boot will still check that it
2011 does not overwrite the U-Boot stack and data).
2013 For instance, when you have a system with 16 MB
2014 RAM, and want to reseve 4 MB from use by Linux,
2015 you can do this by adding "mem=12M" to the value of
2016 the "bootargs" variable. However, now you must make
2017 sure, that the initrd image is placed in the first
2018 12 MB as well - this can be done with
2020 setenv initrd_high 00c00000
2022 If you set initrd_high to 0xFFFFFFFF, this is an
2023 indication to U-Boot that all addresses are legal
2024 for the Linux kernel, including addresses in flash
2025 memory. In this case U-Boot will NOT COPY the
2026 ramdisk at all. This may be useful to reduce the
2027 boot time on your system, but requires that this
2028 feature is supported by your Linux kernel.
2030 ipaddr - IP address; needed for tftpboot command
2032 loadaddr - Default load address for commands like "bootp",
2033 "rarpboot", "tftpboot", "loadb" or "diskboot"
2035 loads_echo - see CONFIG_LOADS_ECHO
2037 serverip - TFTP server IP address; needed for tftpboot command
2039 bootretry - see CONFIG_BOOT_RETRY_TIME
2041 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2043 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2046 The following environment variables may be used and automatically
2047 updated by the network boot commands ("bootp" and "rarpboot"),
2048 depending the information provided by your boot server:
2050 bootfile - see above
2051 dnsip - IP address of your Domain Name Server
2052 gatewayip - IP address of the Gateway (Router) to use
2053 hostname - Target hostname
2055 netmask - Subnet Mask
2056 rootpath - Pathname of the root filesystem on the NFS server
2057 serverip - see above
2060 There are two special Environment Variables:
2062 serial# - contains hardware identification information such
2063 as type string and/or serial number
2064 ethaddr - Ethernet address
2066 These variables can be set only once (usually during manufacturing of
2067 the board). U-Boot refuses to delete or overwrite these variables
2068 once they have been set once.
2071 Further special Environment Variables:
2073 ver - Contains the U-Boot version string as printed
2074 with the "version" command. This variable is
2075 readonly (see CONFIG_VERSION_VARIABLE).
2078 Please note that changes to some configuration parameters may take
2079 only effect after the next boot (yes, that's just like Windoze :-).
2082 Command Line Parsing:
2083 =====================
2085 There are two different command line parsers available with U-Boot:
2086 the old "simple" one, and the much more pwerful "hush" shell:
2088 Old, simple command line parser:
2089 --------------------------------
2091 - supports environment variables (through setenv / saveenv commands)
2092 - several commands on one line, separated by ';'
2093 - variable substitution using "... $(name) ..." syntax
2094 - special characters ('$', ';') can be escaped by prefixing with '\',
2096 setenv bootcmd bootm \$(address)
2097 - You can also escape text by enclosing in single apostrophes, for example:
2098 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2103 - similar to Bourne shell, with control structures like
2104 if...then...else...fi, for...do...done; while...do...done,
2105 until...do...done, ...
2106 - supports environment ("global") variables (through setenv / saveenv
2107 commands) and local shell variables (through standard shell syntax
2108 "name=value"); only environment variables can be used with "run"
2114 (1) If a command line (or an environment variable executed by a "run"
2115 command) contains several commands separated by semicolon, and
2116 one of these commands fails, then the remaining commands will be
2119 (2) If you execute several variables with one call to run (i. e.
2120 calling run with a list af variables as arguments), any failing
2121 command will cause "run" to terminate, i. e. the remaining
2122 variables are not executed.
2124 Note for Redundant Ethernet Interfaces:
2125 =======================================
2127 Some boards come with redundand ethernet interfaces; U-Boot supports
2128 such configurations and is capable of automatic selection of a
2129 "working" interface when needed. MAC assignemnt works as follows:
2131 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2132 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2133 "eth1addr" (=>eth1), "eth2addr", ...
2135 If the network interface stores some valid MAC address (for instance
2136 in SROM), this is used as default address if there is NO correspon-
2137 ding setting in the environment; if the corresponding environment
2138 variable is set, this overrides the settings in the card; that means:
2140 o If the SROM has a valid MAC address, and there is no address in the
2141 environment, the SROM's address is used.
2143 o If there is no valid address in the SROM, and a definition in the
2144 environment exists, then the value from the environment variable is
2147 o If both the SROM and the environment contain a MAC address, and
2148 both addresses are the same, this MAC address is used.
2150 o If both the SROM and the environment contain a MAC address, and the
2151 addresses differ, the value from the environment is used and a
2154 o If neither SROM nor the environment contain a MAC address, an error
2162 The "boot" commands of this monitor operate on "image" files which
2163 can be basicly anything, preceeded by a special header; see the
2164 definitions in include/image.h for details; basicly, the header
2165 defines the following image properties:
2167 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2168 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2169 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2170 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
2171 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2172 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2173 Currently supported: PowerPC).
2174 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2175 Currently supported: uncompressed, gzip).
2181 The header is marked by a special Magic Number, and both the header
2182 and the data portions of the image are secured against corruption by
2189 Although U-Boot should support any OS or standalone application
2190 easily, Linux has always been in the focus during the design of
2193 U-Boot includes many features that so far have been part of some
2194 special "boot loader" code within the Linux kernel. Also, any
2195 "initrd" images to be used are no longer part of one big Linux image;
2196 instead, kernel and "initrd" are separate images. This implementation
2197 serves serveral purposes:
2199 - the same features can be used for other OS or standalone
2200 applications (for instance: using compressed images to reduce the
2201 Flash memory footprint)
2203 - it becomes much easier to port new Linux kernel versions because
2204 lots of low-level, hardware dependend stuff are done by U-Boot
2206 - the same Linux kernel image can now be used with different "initrd"
2207 images; of course this also means that different kernel images can
2208 be run with the same "initrd". This makes testing easier (you don't
2209 have to build a new "zImage.initrd" Linux image when you just
2210 change a file in your "initrd"). Also, a field-upgrade of the
2211 software is easier now.
2217 Porting Linux to U-Boot based systems:
2218 ---------------------------------------
2220 U-Boot cannot save you from doing all the necessary modifications to
2221 configure the Linux device drivers for use with your target hardware
2222 (no, we don't intend to provide a full virtual machine interface to
2225 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2227 Just make sure your machine specific header file (for instance
2228 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2229 Information structure as we define in include/u-boot.h, and make
2230 sure that your definition of IMAP_ADDR uses the same value as your
2231 U-Boot configuration in CFG_IMMR.
2234 Configuring the Linux kernel:
2235 -----------------------------
2237 No specific requirements for U-Boot. Make sure you have some root
2238 device (initial ramdisk, NFS) for your target system.
2241 Building a Linux Image:
2242 -----------------------
2244 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2245 not used. If you use recent kernel source, a new build target
2246 "uImage" will exist which automatically builds an image usable by
2247 U-Boot. Most older kernels also have support for a "pImage" target,
2248 which was introduced for our predecessor project PPCBoot and uses a
2249 100% compatible format.
2258 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2259 encapsulate a compressed Linux kernel image with header information,
2260 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2262 * build a standard "vmlinux" kernel image (in ELF binary format):
2264 * convert the kernel into a raw binary image:
2266 ${CROSS_COMPILE}-objcopy -O binary \
2267 -R .note -R .comment \
2268 -S vmlinux linux.bin
2270 * compress the binary image:
2274 * package compressed binary image for U-Boot:
2276 mkimage -A ppc -O linux -T kernel -C gzip \
2277 -a 0 -e 0 -n "Linux Kernel Image" \
2278 -d linux.bin.gz uImage
2281 The "mkimage" tool can also be used to create ramdisk images for use
2282 with U-Boot, either separated from the Linux kernel image, or
2283 combined into one file. "mkimage" encapsulates the images with a 64
2284 byte header containing information about target architecture,
2285 operating system, image type, compression method, entry points, time
2286 stamp, CRC32 checksums, etc.
2288 "mkimage" can be called in two ways: to verify existing images and
2289 print the header information, or to build new images.
2291 In the first form (with "-l" option) mkimage lists the information
2292 contained in the header of an existing U-Boot image; this includes
2293 checksum verification:
2295 tools/mkimage -l image
2296 -l ==> list image header information
2298 The second form (with "-d" option) is used to build a U-Boot image
2299 from a "data file" which is used as image payload:
2301 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2302 -n name -d data_file image
2303 -A ==> set architecture to 'arch'
2304 -O ==> set operating system to 'os'
2305 -T ==> set image type to 'type'
2306 -C ==> set compression type 'comp'
2307 -a ==> set load address to 'addr' (hex)
2308 -e ==> set entry point to 'ep' (hex)
2309 -n ==> set image name to 'name'
2310 -d ==> use image data from 'datafile'
2312 Right now, all Linux kernels use the same load address (0x00000000),
2313 but the entry point address depends on the kernel version:
2315 - 2.2.x kernels have the entry point at 0x0000000C,
2316 - 2.3.x and later kernels have the entry point at 0x00000000.
2318 So a typical call to build a U-Boot image would read:
2320 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2321 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2322 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2323 > examples/uImage.TQM850L
2324 Image Name: 2.4.4 kernel for TQM850L
2325 Created: Wed Jul 19 02:34:59 2000
2326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2327 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2328 Load Address: 0x00000000
2329 Entry Point: 0x00000000
2331 To verify the contents of the image (or check for corruption):
2333 -> tools/mkimage -l examples/uImage.TQM850L
2334 Image Name: 2.4.4 kernel for TQM850L
2335 Created: Wed Jul 19 02:34:59 2000
2336 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2337 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2338 Load Address: 0x00000000
2339 Entry Point: 0x00000000
2341 NOTE: for embedded systems where boot time is critical you can trade
2342 speed for memory and install an UNCOMPRESSED image instead: this
2343 needs more space in Flash, but boots much faster since it does not
2344 need to be uncompressed:
2346 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2347 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2348 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2349 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2350 > examples/uImage.TQM850L-uncompressed
2351 Image Name: 2.4.4 kernel for TQM850L
2352 Created: Wed Jul 19 02:34:59 2000
2353 Image Type: PowerPC Linux Kernel Image (uncompressed)
2354 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2355 Load Address: 0x00000000
2356 Entry Point: 0x00000000
2359 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2360 when your kernel is intended to use an initial ramdisk:
2362 -> tools/mkimage -n 'Simple Ramdisk Image' \
2363 > -A ppc -O linux -T ramdisk -C gzip \
2364 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2365 Image Name: Simple Ramdisk Image
2366 Created: Wed Jan 12 14:01:50 2000
2367 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2368 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2369 Load Address: 0x00000000
2370 Entry Point: 0x00000000
2373 Installing a Linux Image:
2374 -------------------------
2376 To downloading a U-Boot image over the serial (console) interface,
2377 you must convert the image to S-Record format:
2379 objcopy -I binary -O srec examples/image examples/image.srec
2381 The 'objcopy' does not understand the information in the U-Boot
2382 image header, so the resulting S-Record file will be relative to
2383 address 0x00000000. To load it to a given address, you need to
2384 specify the target address as 'offset' parameter with the 'loads'
2387 Example: install the image to address 0x40100000 (which on the
2388 TQM8xxL is in the first Flash bank):
2390 => erase 40100000 401FFFFF
2396 ## Ready for S-Record download ...
2397 ~>examples/image.srec
2398 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2400 15989 15990 15991 15992
2401 [file transfer complete]
2403 ## Start Addr = 0x00000000
2406 You can check the success of the download using the 'iminfo' command;
2407 this includes a checksum verification so you can be sure no data
2408 corruption happened:
2412 ## Checking Image at 40100000 ...
2413 Image Name: 2.2.13 for initrd on TQM850L
2414 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2415 Data Size: 335725 Bytes = 327 kB = 0 MB
2416 Load Address: 00000000
2417 Entry Point: 0000000c
2418 Verifying Checksum ... OK
2425 The "bootm" command is used to boot an application that is stored in
2426 memory (RAM or Flash). In case of a Linux kernel image, the contents
2427 of the "bootargs" environment variable is passed to the kernel as
2428 parameters. You can check and modify this variable using the
2429 "printenv" and "setenv" commands:
2432 => printenv bootargs
2433 bootargs=root=/dev/ram
2435 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2437 => printenv bootargs
2438 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2441 ## Booting Linux kernel at 40020000 ...
2442 Image Name: 2.2.13 for NFS on TQM850L
2443 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2444 Data Size: 381681 Bytes = 372 kB = 0 MB
2445 Load Address: 00000000
2446 Entry Point: 0000000c
2447 Verifying Checksum ... OK
2448 Uncompressing Kernel Image ... OK
2449 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
2450 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2451 time_init: decrementer frequency = 187500000/60
2452 Calibrating delay loop... 49.77 BogoMIPS
2453 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2456 If you want to boot a Linux kernel with initial ram disk, you pass
2457 the memory addreses of both the kernel and the initrd image (PPBCOOT
2458 format!) to the "bootm" command:
2460 => imi 40100000 40200000
2462 ## Checking Image at 40100000 ...
2463 Image Name: 2.2.13 for initrd on TQM850L
2464 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2465 Data Size: 335725 Bytes = 327 kB = 0 MB
2466 Load Address: 00000000
2467 Entry Point: 0000000c
2468 Verifying Checksum ... OK
2470 ## Checking Image at 40200000 ...
2471 Image Name: Simple Ramdisk Image
2472 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2473 Data Size: 566530 Bytes = 553 kB = 0 MB
2474 Load Address: 00000000
2475 Entry Point: 00000000
2476 Verifying Checksum ... OK
2478 => bootm 40100000 40200000
2479 ## Booting Linux kernel at 40100000 ...
2480 Image Name: 2.2.13 for initrd on TQM850L
2481 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2482 Data Size: 335725 Bytes = 327 kB = 0 MB
2483 Load Address: 00000000
2484 Entry Point: 0000000c
2485 Verifying Checksum ... OK
2486 Uncompressing Kernel Image ... OK
2487 ## Loading RAMDisk Image at 40200000 ...
2488 Image Name: Simple Ramdisk Image
2489 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2490 Data Size: 566530 Bytes = 553 kB = 0 MB
2491 Load Address: 00000000
2492 Entry Point: 00000000
2493 Verifying Checksum ... OK
2494 Loading Ramdisk ... OK
2495 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
2496 Boot arguments: root=/dev/ram
2497 time_init: decrementer frequency = 187500000/60
2498 Calibrating delay loop... 49.77 BogoMIPS
2500 RAMDISK: Compressed image found at block 0
2501 VFS: Mounted root (ext2 filesystem).
2505 More About U-Boot Image Types:
2506 ------------------------------
2508 U-Boot supports the following image types:
2510 "Standalone Programs" are directly runnable in the environment
2511 provided by U-Boot; it is expected that (if they behave
2512 well) you can continue to work in U-Boot after return from
2513 the Standalone Program.
2514 "OS Kernel Images" are usually images of some Embedded OS which
2515 will take over control completely. Usually these programs
2516 will install their own set of exception handlers, device
2517 drivers, set up the MMU, etc. - this means, that you cannot
2518 expect to re-enter U-Boot except by resetting the CPU.
2519 "RAMDisk Images" are more or less just data blocks, and their
2520 parameters (address, size) are passed to an OS kernel that is
2522 "Multi-File Images" contain several images, typically an OS
2523 (Linux) kernel image and one or more data images like
2524 RAMDisks. This construct is useful for instance when you want
2525 to boot over the network using BOOTP etc., where the boot
2526 server provides just a single image file, but you want to get
2527 for instance an OS kernel and a RAMDisk image.
2529 "Multi-File Images" start with a list of image sizes, each
2530 image size (in bytes) specified by an "uint32_t" in network
2531 byte order. This list is terminated by an "(uint32_t)0".
2532 Immediately after the terminating 0 follow the images, one by
2533 one, all aligned on "uint32_t" boundaries (size rounded up to
2534 a multiple of 4 bytes).
2536 "Firmware Images" are binary images containing firmware (like
2537 U-Boot or FPGA images) which usually will be programmed to
2540 "Script files" are command sequences that will be executed by
2541 U-Boot's command interpreter; this feature is especially
2542 useful when you configure U-Boot to use a real shell (hush)
2543 as command interpreter.
2549 One of the features of U-Boot is that you can dynamically load and
2550 run "standalone" applications, which can use some resources of
2551 U-Boot like console I/O functions or interrupt services.
2553 Two simple examples are included with the sources:
2558 'examples/hello_world.c' contains a small "Hello World" Demo
2559 application; it is automatically compiled when you build U-Boot.
2560 It's configured to run at address 0x00040004, so you can play with it
2564 ## Ready for S-Record download ...
2565 ~>examples/hello_world.srec
2566 1 2 3 4 5 6 7 8 9 10 11 ...
2567 [file transfer complete]
2569 ## Start Addr = 0x00040004
2571 => go 40004 Hello World! This is a test.
2572 ## Starting application at 0x00040004 ...
2583 Hit any key to exit ...
2585 ## Application terminated, rc = 0x0
2587 Another example, which demonstrates how to register a CPM interrupt
2588 handler with the U-Boot code, can be found in 'examples/timer.c'.
2589 Here, a CPM timer is set up to generate an interrupt every second.
2590 The interrupt service routine is trivial, just printing a '.'
2591 character, but this is just a demo program. The application can be
2592 controlled by the following keys:
2594 ? - print current values og the CPM Timer registers
2595 b - enable interrupts and start timer
2596 e - stop timer and disable interrupts
2597 q - quit application
2600 ## Ready for S-Record download ...
2601 ~>examples/timer.srec
2602 1 2 3 4 5 6 7 8 9 10 11 ...
2603 [file transfer complete]
2605 ## Start Addr = 0x00040004
2608 ## Starting application at 0x00040004 ...
2611 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2614 [q, b, e, ?] Set interval 1000000 us
2617 [q, b, e, ?] ........
2618 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2621 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2624 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2627 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2629 [q, b, e, ?] ...Stopping timer
2631 [q, b, e, ?] ## Application terminated, rc = 0x0
2638 Over time, many people have reported problems when trying to used the
2639 "minicom" terminal emulation program for serial download. I (wd)
2640 consider minicom to be broken, and recommend not to use it. Under
2641 Unix, I recommend to use C-Kermit for general purpose use (and
2642 especially for kermit binary protocol download ("loadb" command), and
2643 use "cu" for S-Record download ("loads" command).
2648 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2649 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2651 Building requires a cross environment; it is known to work on
2652 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2653 need gmake since the Makefiles are not compatible with BSD make).
2654 Note that the cross-powerpc package does not install include files;
2655 attempting to build U-Boot will fail because <machine/ansi.h> is
2656 missing. This file has to be installed and patched manually:
2658 # cd /usr/pkg/cross/powerpc-netbsd/include
2660 # ln -s powerpc machine
2661 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2662 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2664 Native builds *don't* work due to incompatibilities between native
2665 and U-Boot include files.
2667 Booting assumes that (the first part of) the image booted is a
2668 stage-2 loader which in turn loads and then invokes the kernel
2669 proper. Loader sources will eventually appear in the NetBSD source
2670 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2671 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2675 Implementation Internals:
2676 =========================
2678 The following is not intended to be a complete description of every
2679 implementation detail. However, it should help to understand the
2680 inner workings of U-Boot and make it easier to port it to custom
2684 Initial Stack, Global Data:
2685 ---------------------------
2687 The implementation of U-Boot is complicated by the fact that U-Boot
2688 starts running out of ROM (flash memory), usually without access to
2689 system RAM (because the memory controller is not initialized yet).
2690 This means that we don't have writable Data or BSS segments, and BSS
2691 is not initialized as zero. To be able to get a C environment working
2692 at all, we have to allocate at least a minimal stack. Implementation
2693 options for this are defined and restricted by the CPU used: Some CPU
2694 models provide on-chip memory (like the IMMR area on MPC8xx and
2695 MPC826x processors), on others (parts of) the data cache can be
2696 locked as (mis-) used as memory, etc.
2698 Chris Hallinan posted a good summy of these issues to the
2699 u-boot-users mailing list:
2701 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2702 From: "Chris Hallinan" <clh@net1plus.com>
2703 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2706 Correct me if I'm wrong, folks, but the way I understand it
2707 is this: Using DCACHE as initial RAM for Stack, etc, does not
2708 require any physical RAM backing up the cache. The cleverness
2709 is that the cache is being used as a temporary supply of
2710 necessary storage before the SDRAM controller is setup. It's
2711 beyond the scope of this list to expain the details, but you
2712 can see how this works by studying the cache architecture and
2713 operation in the architecture and processor-specific manuals.
2715 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2716 is another option for the system designer to use as an
2717 initial stack/ram area prior to SDRAM being available. Either
2718 option should work for you. Using CS 4 should be fine if your
2719 board designers haven't used it for something that would
2720 cause you grief during the initial boot! It is frequently not
2723 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2724 with your processor/board/system design. The default value
2725 you will find in any recent u-boot distribution in
2726 Walnut405.h should work for you. I'd set it to a value larger
2727 than your SDRAM module. If you have a 64MB SDRAM module, set
2728 it above 400_0000. Just make sure your board has no resources
2729 that are supposed to respond to that address! That code in
2730 start.S has been around a while and should work as is when
2731 you get the config right.
2736 It is essential to remember this, since it has some impact on the C
2737 code for the initialization procedures:
2739 * Initialized global data (data segment) is read-only. Do not attempt
2742 * Do not use any unitialized global data (or implicitely initialized
2743 as zero data - BSS segment) at all - this is undefined, initiali-
2744 zation is performed later (when relocationg to RAM).
2746 * Stack space is very limited. Avoid big data buffers or things like
2749 Having only the stack as writable memory limits means we cannot use
2750 normal global data to share information beween the code. But it
2751 turned out that the implementation of U-Boot can be greatly
2752 simplified by making a global data structure (gd_t) available to all
2753 functions. We could pass a pointer to this data as argument to _all_
2754 functions, but this would bloat the code. Instead we use a feature of
2755 the GCC compiler (Global Register Variables) to share the data: we
2756 place a pointer (gd) to the global data into a register which we
2757 reserve for this purpose.
2759 When chosing a register for such a purpose we are restricted by the
2760 relevant (E)ABI specifications for the current architecture, and by
2761 GCC's implementation.
2763 For PowerPC, the following registers have specific use:
2766 R3-R4: parameter passing and return values
2767 R5-R10: parameter passing
2768 R13: small data area pointer
2772 (U-Boot also uses R14 as internal GOT pointer.)
2774 ==> U-Boot will use R29 to hold a pointer to the global data
2776 Note: on PPC, we could use a static initializer (since the
2777 address of the global data structure is known at compile time),
2778 but it turned out that reserving a register results in somewhat
2779 smaller code - although the code savings are not that big (on
2780 average for all boards 752 bytes for the whole U-Boot image,
2781 624 text + 127 data).
2783 On ARM, the following registers are used:
2785 R0: function argument word/integer result
2786 R1-R3: function argument word
2788 R10: stack limit (used only if stack checking if enabled)
2789 R11: argument (frame) pointer
2790 R12: temporary workspace
2793 R15: program counter
2795 ==> U-Boot will use R8 to hold a pointer to the global data
2802 U-Boot runs in system state and uses physical addresses, i.e. the
2803 MMU is not used either for address mapping nor for memory protection.
2805 The available memory is mapped to fixed addresses using the memory
2806 controller. In this process, a contiguous block is formed for each
2807 memory type (Flash, SDRAM, SRAM), even when it consists of several
2808 physical memory banks.
2810 U-Boot is installed in the first 128 kB of the first Flash bank (on
2811 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2812 booting and sizing and initializing DRAM, the code relocates itself
2813 to the upper end of DRAM. Immediately below the U-Boot code some
2814 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2815 configuration setting]. Below that, a structure with global Board
2816 Info data is placed, followed by the stack (growing downward).
2818 Additionally, some exception handler code is copied to the low 8 kB
2819 of DRAM (0x00000000 ... 0x00001FFF).
2821 So a typical memory configuration with 16 MB of DRAM could look like
2824 0x0000 0000 Exception Vector code
2827 0x0000 2000 Free for Application Use
2833 0x00FB FF20 Monitor Stack (Growing downward)
2834 0x00FB FFAC Board Info Data and permanent copy of global data
2835 0x00FC 0000 Malloc Arena
2838 0x00FE 0000 RAM Copy of Monitor Code
2839 ... eventually: LCD or video framebuffer
2840 ... eventually: pRAM (Protected RAM - unchanged by reset)
2841 0x00FF FFFF [End of RAM]
2844 System Initialization:
2845 ----------------------
2847 In the reset configuration, U-Boot starts at the reset entry point
2848 (on most PowerPC systens at address 0x00000100). Because of the reset
2849 configuration for CS0# this is a mirror of the onboard Flash memory.
2850 To be able to re-map memory U-Boot then jumps to it's link address.
2851 To be able to implement the initialization code in C, a (small!)
2852 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2853 which provide such a feature like MPC8xx or MPC8260), or in a locked
2854 part of the data cache. After that, U-Boot initializes the CPU core,
2855 the caches and the SIU.
2857 Next, all (potentially) available memory banks are mapped using a
2858 preliminary mapping. For example, we put them on 512 MB boundaries
2859 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2860 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2861 programmed for SDRAM access. Using the temporary configuration, a
2862 simple memory test is run that determines the size of the SDRAM
2865 When there is more than one SDRAM bank, and the banks are of
2866 different size, the larger is mapped first. For equal size, the first
2867 bank (CS2#) is mapped first. The first mapping is always for address
2868 0x00000000, with any additional banks following immediately to create
2869 contiguous memory starting from 0.
2871 Then, the monitor installs itself at the upper end of the SDRAM area
2872 and allocates memory for use by malloc() and for the global Board
2873 Info data; also, the exception vector code is copied to the low RAM
2874 pages, and the final stack is set up.
2876 Only after this relocation will you have a "normal" C environment;
2877 until that you are restricted in several ways, mostly because you are
2878 running from ROM, and because the code will have to be relocated to a
2882 U-Boot Porting Guide:
2883 ----------------------
2885 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2889 int main (int argc, char *argv[])
2891 sighandler_t no_more_time;
2893 signal (SIGALRM, no_more_time);
2894 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2896 if (available_money > available_manpower) {
2897 pay consultant to port U-Boot;
2901 Download latest U-Boot source;
2903 Subscribe to u-boot-users mailing list;
2906 email ("Hi, I am new to U-Boot, how do I get started?");
2910 Read the README file in the top level directory;
2911 Read http://www.denx.de/re/DPLG.html
2912 Read the source, Luke;
2915 if (available_money > toLocalCurrency ($2500)) {
2918 Add a lot of aggravation and time;
2921 Create your own board support subdirectory;
2923 Create your own board config file;
2927 Add / modify source code;
2931 email ("Hi, I am having problems...");
2933 Send patch file to Wolfgang;
2938 void no_more_time (int sig)
2948 All contributions to U-Boot should conform to the Linux kernel
2949 coding style; see the file "Documentation/CodingStyle" in your Linux
2950 kernel source directory.
2952 Please note that U-Boot is implemented in C (and to some small parts
2953 in Assembler); no C++ is used, so please do not use C++ style
2954 comments (//) in your code.
2956 Submissions which do not conform to the standards may be returned
2957 with a request to reformat the changes.
2963 Since the number of patches for U-Boot is growing, we need to
2964 establish some rules. Submissions which do not conform to these rules
2965 may be rejected, even when they contain important and valuable stuff.
2968 When you send a patch, please include the following information with
2971 * For bug fixes: a description of the bug and how your patch fixes
2972 this bug. Please try to include a way of demonstrating that the
2973 patch actually fixes something.
2975 * For new features: a description of the feature and your
2978 * A CHANGELOG entry as plaintext (separate from the patch)
2980 * For major contributions, your entry to the CREDITS file
2982 * When you add support for a new board, don't forget to add this
2983 board to the MAKEALL script, too.
2985 * If your patch adds new configuration options, don't forget to
2986 document these in the README file.
2988 * The patch itself. If you are accessing the CVS repository use "cvs
2989 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2990 version of diff does not support these options, then get the latest
2991 version of GNU diff.
2993 We accept patches as plain text, MIME attachments or as uuencoded
2998 * Before sending the patch, run the MAKEALL script on your patched
2999 source tree and make sure that no errors or warnings are reported
3000 for any of the boards.
3002 * Keep your modifications to the necessary minimum: A patch
3003 containing several unrelated changes or arbitrary reformats will be
3004 returned with a request to re-formatting / split it.
3006 * If you modify existing code, make sure that your new code does not
3007 add to the memory footprint of the code ;-) Small is beautiful!
3008 When adding new features, these should compile conditionally only
3009 (using #ifdef), and the resulting code with the new feature
3010 disabled must not need more memory than the old code without your
projects / platform / kernel / u-boot.git / blob