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/at91rm9200dk Files specific to AT91RM9200DK boards
155 - board/c2mon Files specific to c2mon boards
156 - board/cmi Files specific to cmi boards
157 - board/cogent Files specific to Cogent boards
158 (need further configuration)
159 Files specific to CPCIISER4 boards
160 - board/cpu86 Files specific to CPU86 boards
161 - board/cray/ Files specific to boards manufactured by Cray
162 - board/cray/L1 Files specific to L1 boards
163 - board/cu824 Files specific to CU824 boards
164 - board/ebony Files specific to IBM Ebony board
165 - board/eric Files specific to ERIC boards
166 - board/esd/ Files specific to boards manufactured by ESD
167 - board/esd/adciop Files specific to ADCIOP boards
168 - board/esd/ar405 Files specific to AR405 boards
169 - board/esd/canbt Files specific to CANBT boards
170 - board/esd/cpci405 Files specific to CPCI405 boards
171 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
172 - board/esd/common Common files for ESD boards
173 - board/esd/dasa_sim Files specific to DASA_SIM boards
174 - board/esd/du405 Files specific to DU405 boards
175 - board/esd/ocrtc Files specific to OCRTC boards
176 - board/esd/pci405 Files specific to PCI405 boards
178 Files specific to ESTEEM192E boards
179 - board/etx094 Files specific to ETX_094 boards
181 Files specific to EVB64260 boards
182 - board/fads Files specific to FADS boards
183 - board/flagadm Files specific to FLAGADM boards
184 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
185 - board/genietv Files specific to GENIETV boards
186 - board/gth Files specific to GTH boards
187 - board/hermes Files specific to HERMES boards
188 - board/hymod Files specific to HYMOD boards
189 - board/icu862 Files specific to ICU862 boards
190 - board/ip860 Files specific to IP860 boards
192 Files specific to Interphase4539 boards
193 - board/ivm Files specific to IVMS8/IVML24 boards
194 - board/lantec Files specific to LANTEC boards
195 - board/lwmon Files specific to LWMON boards
196 - board/mbx8xx Files specific to MBX boards
198 Files specific to MMPC8260ADS boards
199 - board/mpl/ Files specific to boards manufactured by MPL
200 - board/mpl/common Common files for MPL boards
201 - board/mpl/pip405 Files specific to PIP405 boards
202 - board/mpl/mip405 Files specific to MIP405 boards
203 - board/musenki Files specific to MUSEKNI boards
204 - board/mvs1 Files specific to MVS1 boards
205 - board/nx823 Files specific to NX823 boards
206 - board/oxc Files specific to OXC boards
207 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
208 - board/pm826 Files specific to PM826 boards
210 Files specific to PPMC8260 boards
212 Files specific to RPXsuper boards
214 Files specific to RSDproto boards
216 Files specific to Sandpoint boards
217 - board/sbc8260 Files specific to SBC8260 boards
218 - board/sacsng Files specific to SACSng boards
219 - board/siemens Files specific to boards manufactured by Siemens AG
220 - board/siemens/CCM Files specific to CCM boards
221 - board/siemens/IAD210 Files specific to IAD210 boards
222 - board/siemens/SCM Files specific to SCM boards
223 - board/siemens/pcu_e Files specific to PCU_E boards
224 - board/sixnet Files specific to SIXNET boards
225 - board/spd8xx Files specific to SPD8xxTS boards
226 - board/tqm8260 Files specific to TQM8260 boards
227 - board/tqm8xx Files specific to TQM8xxL boards
228 - board/w7o Files specific to W7O boards
230 Files specific to Walnut405 boards
231 - board/westel/ Files specific to boards manufactured by Westel Wireless
232 - board/westel/amx860 Files specific to AMX860 boards
233 - board/utx8245 Files specific to UTX8245 boards
235 Software Configuration:
236 =======================
238 Configuration is usually done using C preprocessor defines; the
239 rationale behind that is to avoid dead code whenever possible.
241 There are two classes of configuration variables:
243 * Configuration _OPTIONS_:
244 These are selectable by the user and have names beginning with
247 * Configuration _SETTINGS_:
248 These depend on the hardware etc. and should not be meddled with if
249 you don't know what you're doing; they have names beginning with
252 Later we will add a configuration tool - probably similar to or even
253 identical to what's used for the Linux kernel. Right now, we have to
254 do the configuration by hand, which means creating some symbolic
255 links and editing some configuration files. We use the TQM8xxL boards
259 Selection of Processor Architecture and Board Type:
260 ---------------------------------------------------
262 For all supported boards there are ready-to-use default
263 configurations available; just type "make <board_name>_config".
265 Example: For a TQM823L module type:
270 For the Cogent platform, you need to specify the cpu type as well;
271 e.g. "make cogent_mpc8xx_config". And also configure the cogent
272 directory according to the instructions in cogent/README.
275 Configuration Options:
276 ----------------------
278 Configuration depends on the combination of board and CPU type; all
279 such information is kept in a configuration file
280 "include/configs/<board_name>.h".
282 Example: For a TQM823L module, all configuration settings are in
283 "include/configs/TQM823L.h".
286 Many of the options are named exactly as the corresponding Linux
287 kernel configuration options. The intention is to make it easier to
288 build a config tool - later.
291 The following options need to be configured:
293 - CPU Type: Define exactly one of
297 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
299 or CONFIG_MPC824X, CONFIG_MPC8260
313 - Board Type: Define exactly one of
315 PowerPC based boards:
316 ---------------------
318 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
319 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
320 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
321 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
322 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
323 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
324 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
325 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
326 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
327 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
328 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
329 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
330 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
331 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
332 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
333 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
334 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
335 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
336 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
337 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
338 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
339 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
340 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
341 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
342 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
343 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
344 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
345 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
346 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
347 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
348 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
349 CONFIG_NETVIA, CONFIG_RBC823
354 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
355 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
356 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
357 CONFIG_TRAB, CONFIG_AT91RM9200DK
360 - CPU Module Type: (if CONFIG_COGENT is defined)
361 Define exactly one of
363 --- FIXME --- not tested yet:
364 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
365 CONFIG_CMA287_23, CONFIG_CMA287_50
367 - Motherboard Type: (if CONFIG_COGENT is defined)
368 Define exactly one of
369 CONFIG_CMA101, CONFIG_CMA102
371 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
372 Define one or more of
375 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
376 Define one or more of
377 CONFIG_LCD_HEARTBEAT - update a character position on
378 the lcd display every second with
381 - MPC824X Family Member (if CONFIG_MPC824X is defined)
382 Define exactly one of
383 CONFIG_MPC8240, CONFIG_MPC8245
385 - 8xx CPU Options: (if using an 8xx cpu)
386 Define one or more of
387 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
388 no 32KHz reference PIT/RTC clock
393 U-Boot stores all clock information in Hz
394 internally. For binary compatibility with older Linux
395 kernels (which expect the clocks passed in the
396 bd_info data to be in MHz) the environment variable
397 "clocks_in_mhz" can be defined so that U-Boot
398 converts clock data to MHZ before passing it to the
401 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
402 "clocks_in_mhz=1" is automatically included in the
406 Depending on board, define exactly one serial port
407 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
408 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
409 console by defining CONFIG_8xx_CONS_NONE
411 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
412 port routines must be defined elsewhere
413 (i.e. serial_init(), serial_getc(), ...)
416 Enables console device for a color framebuffer. Needs following
417 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
418 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
420 VIDEO_HW_RECTFILL graphic chip supports
423 VIDEO_HW_BITBLT graphic chip supports
424 bit-blit (cf. smiLynxEM)
425 VIDEO_VISIBLE_COLS visible pixel columns
427 VIDEO_VISIBLE_ROWS visible pixel rows
428 VIDEO_PIXEL_SIZE bytes per pixel
429 VIDEO_DATA_FORMAT graphic data format
430 (0-5, cf. cfb_console.c)
431 VIDEO_FB_ADRS framebuffer address
432 VIDEO_KBD_INIT_FCT keyboard int fct
433 (i.e. i8042_kbd_init())
434 VIDEO_TSTC_FCT test char fct
436 VIDEO_GETC_FCT get char fct
438 CONFIG_CONSOLE_CURSOR cursor drawing on/off
439 (requires blink timer
441 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
442 CONFIG_CONSOLE_TIME display time/date info in
444 (requires CFG_CMD_DATE)
445 CONFIG_VIDEO_LOGO display Linux logo in
447 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
448 linux_logo.h for logo.
449 Requires CONFIG_VIDEO_LOGO
450 CONFIG_CONSOLE_EXTRA_INFO
451 addional board info beside
454 When CONFIG_CFB_CONSOLE is defined, video console is
455 default i/o. Serial console can be forced with
456 environment 'console=serial'.
459 CONFIG_BAUDRATE - in bps
460 Select one of the baudrates listed in
461 CFG_BAUDRATE_TABLE, see below.
463 - Interrupt driven serial port input:
464 CONFIG_SERIAL_SOFTWARE_FIFO
467 Use an interrupt handler for receiving data on the
468 serial port. It also enables using hardware handshake
469 (RTS/CTS) and UART's built-in FIFO. Set the number of
470 bytes the interrupt driven input buffer should have.
472 Set to 0 to disable this feature (this is the default).
473 This will also disable hardware handshake.
475 - Console UART Number:
479 If defined internal UART1 (and not UART0) is used
480 as default U-Boot console.
482 - Boot Delay: CONFIG_BOOTDELAY - in seconds
483 Delay before automatically booting the default image;
484 set to -1 to disable autoboot.
486 See doc/README.autoboot for these options that
487 work with CONFIG_BOOTDELAY. None are required.
488 CONFIG_BOOT_RETRY_TIME
489 CONFIG_BOOT_RETRY_MIN
490 CONFIG_AUTOBOOT_KEYED
491 CONFIG_AUTOBOOT_PROMPT
492 CONFIG_AUTOBOOT_DELAY_STR
493 CONFIG_AUTOBOOT_STOP_STR
494 CONFIG_AUTOBOOT_DELAY_STR2
495 CONFIG_AUTOBOOT_STOP_STR2
496 CONFIG_ZERO_BOOTDELAY_CHECK
497 CONFIG_RESET_TO_RETRY
501 Only needed when CONFIG_BOOTDELAY is enabled;
502 define a command string that is automatically executed
503 when no character is read on the console interface
504 within "Boot Delay" after reset.
507 This can be used to pass arguments to the bootm
508 command. The value of CONFIG_BOOTARGS goes into the
509 environment value "bootargs".
511 CONFIG_RAMBOOT and CONFIG_NFSBOOT
512 The value of these goes into the environment as
513 "ramboot" and "nfsboot" respectively, and can be used
514 as a convenience, when switching between booting from
520 When this option is #defined, the existence of the
521 environment variable "preboot" will be checked
522 immediately before starting the CONFIG_BOOTDELAY
523 countdown and/or running the auto-boot command resp.
524 entering interactive mode.
526 This feature is especially useful when "preboot" is
527 automatically generated or modified. For an example
528 see the LWMON board specific code: here "preboot" is
529 modified when the user holds down a certain
530 combination of keys on the (special) keyboard when
533 - Serial Download Echo Mode:
535 If defined to 1, all characters received during a
536 serial download (using the "loads" command) are
537 echoed back. This might be needed by some terminal
538 emulations (like "cu"), but may as well just take
539 time on others. This setting #define's the initial
540 value of the "loads_echo" environment variable.
542 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
544 Select one of the baudrates listed in
545 CFG_BAUDRATE_TABLE, see below.
549 Most monitor functions can be selected (or
550 de-selected) by adjusting the definition of
551 CONFIG_COMMANDS; to select individual functions,
552 #define CONFIG_COMMANDS by "OR"ing any of the
555 #define enables commands:
556 -------------------------
557 CFG_CMD_ASKENV * ask for env variable
559 CFG_CMD_BEDBUG Include BedBug Debugger
561 CFG_CMD_CACHE icache, dcache
562 CFG_CMD_CONSOLE coninfo
563 CFG_CMD_DATE * support for RTC, date/time...
564 CFG_CMD_DHCP DHCP support
565 CFG_CMD_ECHO * echo arguments
566 CFG_CMD_EEPROM * EEPROM read/write support
567 CFG_CMD_ELF bootelf, bootvx
569 CFG_CMD_FDC * Floppy Disk Support
570 CFG_CMD_FAT FAT partition support
571 CFG_CMD_FDOS * Dos diskette Support
572 CFG_CMD_FLASH flinfo, erase, protect
573 CFG_CMD_FPGA FPGA device initialization support
574 CFG_CMD_I2C * I2C serial bus support
575 CFG_CMD_IDE * IDE harddisk support
577 CFG_CMD_IMMAP * IMMR dump support
578 CFG_CMD_IRQ * irqinfo
582 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
584 CFG_CMD_MMC MMC memory mapped support
585 CFG_CMD_MII MII utility commands
586 CFG_CMD_NET bootp, tftpboot, rarpboot
587 CFG_CMD_PCI * pciinfo
588 CFG_CMD_PCMCIA * PCMCIA support
589 CFG_CMD_REGINFO * Register dump
590 CFG_CMD_RUN run command in env variable
591 CFG_CMD_SCSI * SCSI Support
592 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
593 CFG_CMD_SPI * SPI serial bus support
594 CFG_CMD_USB * USB support
595 CFG_CMD_BSP * Board SPecific functions
596 -----------------------------------------------
599 CFG_CMD_DFL Default configuration; at the moment
600 this is includes all commands, except
601 the ones marked with "*" in the list
604 If you don't define CONFIG_COMMANDS it defaults to
605 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
606 override the default settings in the respective
609 EXAMPLE: If you want all functions except of network
610 support you can write:
612 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
615 Note: Don't enable the "icache" and "dcache" commands
616 (configuration option CFG_CMD_CACHE) unless you know
617 what you (and your U-Boot users) are doing. Data
618 cache cannot be enabled on systems like the 8xx or
619 8260 (where accesses to the IMMR region must be
620 uncached), and it cannot be disabled on all other
621 systems where we (mis-) use the data cache to hold an
622 initial stack and some data.
625 XXX - this list needs to get updated!
629 If this variable is defined, it enables watchdog
630 support. There must support in the platform specific
631 code for a watchdog. For the 8xx and 8260 CPUs, the
632 SIU Watchdog feature is enabled in the SYPCR
636 CONFIG_VERSION_VARIABLE
637 If this variable is defined, an environment variable
638 named "ver" is created by U-Boot showing the U-Boot
639 version as printed by the "version" command.
640 This variable is readonly.
644 When CFG_CMD_DATE is selected, the type of the RTC
645 has to be selected, too. Define exactly one of the
648 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
649 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
650 CONFIG_RTC_MC146818 - use MC146818 RTC
651 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
652 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
653 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
654 CONFIG_RTC_DS164x - use Dallas DS164x RTC
658 When CONFIG_TIMESTAMP is selected, the timestamp
659 (date and time) of an image is printed by image
660 commands like bootm or iminfo. This option is
661 automatically enabled when you select CFG_CMD_DATE .
664 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
665 and/or CONFIG_ISO_PARTITION
667 If IDE or SCSI support is enabled (CFG_CMD_IDE or
668 CFG_CMD_SCSI) you must configure support for at least
669 one partition type as well.
672 CONFIG_IDE_RESET_ROUTINE
674 Set this to define that instead of a reset Pin, the
675 routine ide_set_reset(int idereset) will be used.
680 Set this to enable ATAPI support.
683 At the moment only there is only support for the
684 SYM53C8XX SCSI controller; define
685 CONFIG_SCSI_SYM53C8XX to enable it.
687 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
688 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
689 CFG_SCSI_MAX_LUN] can be adjusted to define the
690 maximum numbers of LUNs, SCSI ID's and target
692 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
694 - NETWORK Support (PCI):
696 Support for Intel 8254x gigabit chips.
699 Support for Intel 82557/82559/82559ER chips.
700 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
701 write routine for first time initialisation.
704 Support for Digital 2114x chips.
705 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
706 modem chip initialisation (KS8761/QS6611).
709 Support for National dp83815 chips.
712 Support for National dp8382[01] gigabit chips.
714 - NETWORK Support (other):
716 CONFIG_DRIVER_LAN91C96
717 Support for SMSC's LAN91C96 chips.
720 Define this to hold the physical address
721 of the LAN91C96's I/O space
723 CONFIG_LAN91C96_USE_32_BIT
724 Define this to enable 32 bit addressing
727 At the moment only the UHCI host controller is
728 supported (PIP405, MIP405); define
729 CONFIG_USB_UHCI to enable it.
730 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
731 end define CONFIG_USB_STORAGE to enable the USB
734 Supported are USB Keyboards and USB Floppy drives
738 The MMC controller on the Intel PXA is supported. To
739 enable this define CONFIG_MMC. The MMC can be
740 accessed from the boot prompt by mapping the device
741 to physical memory similar to flash. Command line is
742 enabled with CFG_CMD_MMC. The MMC driver also works with
743 the FAT fs. This is enabled with CFG_CMD_FAT.
748 Define this to enable standard (PC-Style) keyboard
752 Standard PC keyboard driver with US (is default) and
753 GERMAN key layout (switch via environment 'keymap=de') support.
754 Export function i8042_kbd_init, i8042_tstc and i8042_getc
755 for cfb_console. Supports cursor blinking.
760 Define this to enable video support (for output to
765 Enable Chips & Technologies 69000 Video chip
767 CONFIG_VIDEO_SMI_LYNXEM
768 Enable Silicon Motion SMI 712/710/810 Video chip
769 Videomode are selected via environment 'videomode' with
770 standard LiLo mode numbers.
771 Following modes are supported (* is default):
773 800x600 1024x768 1280x1024
774 256 (8bit) 303* 305 307
775 65536 (16bit) 314 317 31a
776 16,7 Mill (24bit) 315 318 31b
777 (i.e. setenv videomode 317; saveenv; reset;)
779 CONFIG_VIDEO_SED13806
780 Enable Epson SED13806 driver. This driver supports 8bpp
781 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
782 or CONFIG_VIDEO_SED13806_16BPP
787 Define this to enable a custom keyboard support.
788 This simply calls drv_keyboard_init() which must be
789 defined in your board-specific files.
790 The only board using this so far is RBC823.
792 - LCD Support: CONFIG_LCD
794 Define this to enable LCD support (for output to LCD
795 display); also select one of the supported displays
796 by defining one of these:
798 CONFIG_NEC_NL6648AC33:
800 NEC NL6648AC33-18. Active, color, single scan.
802 CONFIG_NEC_NL6648BC20
804 NEC NL6648BC20-08. 6.5", 640x480.
805 Active, color, single scan.
809 Sharp 320x240. Active, color, single scan.
810 It isn't 16x9, and I am not sure what it is.
812 CONFIG_SHARP_LQ64D341
814 Sharp LQ64D341 display, 640x480.
815 Active, color, single scan.
819 HLD1045 display, 640x480.
820 Active, color, single scan.
824 Optrex CBL50840-2 NF-FW 99 22 M5
826 Hitachi LMG6912RPFC-00T
830 320x240. Black & white.
832 Normally display is black on white background; define
833 CFG_WHITE_ON_BLACK to get it inverted.
835 - Spash Screen Support: CONFIG_SPLASH_SCREEN
837 If this option is set, the environment is checked for
838 a variable "splashimage". If found, the usual display
839 of logo, copyright and system information on the LCD
840 is supressed and the BMP image at the address
841 specified in "splashimage" is loaded instead. The
842 console is redirected to the "nulldev", too. This
843 allows for a "silent" boot where a splash screen is
844 loaded very quickly after power-on.
852 Define a default value for ethernet address to use
853 for the respective ethernet interface, in case this
854 is not determined automatically.
859 Define a default value for the IP address to use for
860 the default ethernet interface, in case this is not
861 determined through e.g. bootp.
866 Defines a default value for theIP address of a TFTP
867 server to contact when using the "tftboot" command.
869 - BOOTP Recovery Mode:
870 CONFIG_BOOTP_RANDOM_DELAY
872 If you have many targets in a network that try to
873 boot using BOOTP, you may want to avoid that all
874 systems send out BOOTP requests at precisely the same
875 moment (which would happen for instance at recovery
876 from a power failure, when all systems will try to
877 boot, thus flooding the BOOTP server. Defining
878 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
879 inserted before sending out BOOTP requests. The
880 following delays are insterted then:
882 1st BOOTP request: delay 0 ... 1 sec
883 2nd BOOTP request: delay 0 ... 2 sec
884 3rd BOOTP request: delay 0 ... 4 sec
886 BOOTP requests: delay 0 ... 8 sec
888 - Status LED: CONFIG_STATUS_LED
890 Several configurations allow to display the current
891 status using a LED. For instance, the LED will blink
892 fast while running U-Boot code, stop blinking as
893 soon as a reply to a BOOTP request was received, and
894 start blinking slow once the Linux kernel is running
895 (supported by a status LED driver in the Linux
896 kernel). Defining CONFIG_STATUS_LED enables this
899 - CAN Support: CONFIG_CAN_DRIVER
901 Defining CONFIG_CAN_DRIVER enables CAN driver support
902 on those systems that support this (optional)
903 feature, like the TQM8xxL modules.
905 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
907 Enables I2C serial bus commands. If this is selected,
908 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
909 to include the appropriate I2C driver.
911 See also: common/cmd_i2c.c for a description of the
912 command line interface.
917 Selects the CPM hardware driver for I2C.
921 Use software (aka bit-banging) driver instead of CPM
922 or similar hardware support for I2C. This is configured
923 via the following defines.
927 (Optional). Any commands necessary to enable I2C
928 controller or configure ports.
932 (Only for MPC8260 CPU). The I/O port to use (the code
933 assumes both bits are on the same port). Valid values
934 are 0..3 for ports A..D.
938 The code necessary to make the I2C data line active
939 (driven). If the data line is open collector, this
944 The code necessary to make the I2C data line tri-stated
945 (inactive). If the data line is open collector, this
950 Code that returns TRUE if the I2C data line is high,
955 If <bit> is TRUE, sets the I2C data line high. If it
956 is FALSE, it clears it (low).
960 If <bit> is TRUE, sets the I2C clock line high. If it
961 is FALSE, it clears it (low).
965 This delay is invoked four times per clock cycle so this
966 controls the rate of data transfer. The data rate thus
967 is 1 / (I2C_DELAY * 4).
971 When a board is reset during an i2c bus transfer
972 chips might think that the current transfer is still
973 in progress. On some boards it is possible to access
974 the i2c SCLK line directly, either by using the
975 processor pin as a GPIO or by having a second pin
976 connected to the bus. If this option is defined a
977 custom i2c_init_board() routine in boards/xxx/board.c
978 is run early in the boot sequence.
980 - SPI Support: CONFIG_SPI
982 Enables SPI driver (so far only tested with
983 SPI EEPROM, also an instance works with Crystal A/D and
984 D/As on the SACSng board)
988 Enables extended (16-bit) SPI EEPROM addressing.
989 (symmetrical to CONFIG_I2C_X)
993 Enables a software (bit-bang) SPI driver rather than
994 using hardware support. This is a general purpose
995 driver that only requires three general I/O port pins
996 (two outputs, one input) to function. If this is
997 defined, the board configuration must define several
998 SPI configuration items (port pins to use, etc). For
999 an example, see include/configs/sacsng.h.
1001 - FPGA Support: CONFIG_FPGA_COUNT
1003 Specify the number of FPGA devices to support.
1007 Used to specify the types of FPGA devices. For
1009 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1011 CFG_FPGA_PROG_FEEDBACK
1013 Enable printing of hash marks during FPGA
1018 Enable checks on FPGA configuration interface busy
1019 status by the configuration function. This option
1020 will require a board or device specific function to
1025 If defined, a function that provides delays in the
1026 FPGA configuration driver.
1028 CFG_FPGA_CHECK_CTRLC
1030 Allow Control-C to interrupt FPGA configuration
1032 CFG_FPGA_CHECK_ERROR
1034 Check for configuration errors during FPGA bitfile
1035 loading. For example, abort during Virtex II
1036 configuration if the INIT_B line goes low (which
1037 indicated a CRC error).
1041 Maximum time to wait for the INIT_B line to deassert
1042 after PROB_B has been deasserted during a Virtex II
1043 FPGA configuration sequence. The default time is 500 mS.
1047 Maximum time to wait for BUSY to deassert during
1048 Virtex II FPGA configuration. The default is 5 mS.
1050 CFG_FPGA_WAIT_CONFIG
1052 Time to wait after FPGA configuration. The default is
1055 - FPGA Support: CONFIG_FPGA_COUNT
1057 Specify the number of FPGA devices to support.
1061 Used to specify the types of FPGA devices. For example,
1062 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1064 CFG_FPGA_PROG_FEEDBACK
1066 Enable printing of hash marks during FPGA configuration.
1070 Enable checks on FPGA configuration interface busy
1071 status by the configuration function. This option
1072 will require a board or device specific function to
1077 If defined, a function that provides delays in the FPGA
1078 configuration driver.
1080 CFG_FPGA_CHECK_CTRLC
1081 Allow Control-C to interrupt FPGA configuration
1083 CFG_FPGA_CHECK_ERROR
1085 Check for configuration errors during FPGA bitfile
1086 loading. For example, abort during Virtex II
1087 configuration if the INIT_B line goes low (which
1088 indicated a CRC error).
1092 Maximum time to wait for the INIT_B line to deassert
1093 after PROB_B has been deasserted during a Virtex II
1094 FPGA configuration sequence. The default time is 500
1099 Maximum time to wait for BUSY to deassert during
1100 Virtex II FPGA configuration. The default is 5 mS.
1102 CFG_FPGA_WAIT_CONFIG
1104 Time to wait after FPGA configuration. The default is
1107 - Configuration Management:
1110 If defined, this string will be added to the U-Boot
1111 version information (U_BOOT_VERSION)
1113 - Vendor Parameter Protection:
1115 U-Boot considers the values of the environment
1116 variables "serial#" (Board Serial Number) and
1117 "ethaddr" (Ethernet Address) to bb parameters that
1118 are set once by the board vendor / manufacturer, and
1119 protects these variables from casual modification by
1120 the user. Once set, these variables are read-only,
1121 and write or delete attempts are rejected. You can
1122 change this behviour:
1124 If CONFIG_ENV_OVERWRITE is #defined in your config
1125 file, the write protection for vendor parameters is
1126 completely disabled. Anybody can change or delete
1129 Alternatively, if you #define _both_ CONFIG_ETHADDR
1130 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1131 ethernet address is installed in the environment,
1132 which can be changed exactly ONCE by the user. [The
1133 serial# is unaffected by this, i. e. it remains
1139 Define this variable to enable the reservation of
1140 "protected RAM", i. e. RAM which is not overwritten
1141 by U-Boot. Define CONFIG_PRAM to hold the number of
1142 kB you want to reserve for pRAM. You can overwrite
1143 this default value by defining an environment
1144 variable "pram" to the number of kB you want to
1145 reserve. Note that the board info structure will
1146 still show the full amount of RAM. If pRAM is
1147 reserved, a new environment variable "mem" will
1148 automatically be defined to hold the amount of
1149 remaining RAM in a form that can be passed as boot
1150 argument to Linux, for instance like that:
1152 setenv bootargs ... mem=\$(mem)
1155 This way you can tell Linux not to use this memory,
1156 either, which results in a memory region that will
1157 not be affected by reboots.
1159 *WARNING* If your board configuration uses automatic
1160 detection of the RAM size, you must make sure that
1161 this memory test is non-destructive. So far, the
1162 following board configurations are known to be
1165 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1166 HERMES, IP860, RPXlite, LWMON, LANTEC,
1167 PCU_E, FLAGADM, TQM8260
1172 Define this variable to stop the system in case of a
1173 fatal error, so that you have to reset it manually.
1174 This is probably NOT a good idea for an embedded
1175 system where you want to system to reboot
1176 automatically as fast as possible, but it may be
1177 useful during development since you can try to debug
1178 the conditions that lead to the situation.
1180 CONFIG_NET_RETRY_COUNT
1182 This variable defines the number of retries for
1183 network operations like ARP, RARP, TFTP, or BOOTP
1184 before giving up the operation. If not defined, a
1185 default value of 5 is used.
1187 - Command Interpreter:
1190 Define this variable to enable the "hush" shell (from
1191 Busybox) as command line interpreter, thus enabling
1192 powerful command line syntax like
1193 if...then...else...fi conditionals or `&&' and '||'
1194 constructs ("shell scripts").
1196 If undefined, you get the old, much simpler behaviour
1197 with a somewhat smaller memory footprint.
1202 This defines the secondary prompt string, which is
1203 printed when the command interpreter needs more input
1204 to complete a command. Usually "> ".
1208 In the current implementation, the local variables
1209 space and global environment variables space are
1210 separated. Local variables are those you define by
1211 simply typing `name=value'. To access a local
1212 variable later on, you have write `$name' or
1213 `${name}'; to execute the contents of a variable
1214 directly type `$name' at the command prompt.
1216 Global environment variables are those you use
1217 setenv/printenv to work with. To run a command stored
1218 in such a variable, you need to use the run command,
1219 and you must not use the '$' sign to access them.
1221 To store commands and special characters in a
1222 variable, please use double quotation marks
1223 surrounding the whole text of the variable, instead
1224 of the backslashes before semicolons and special
1227 - Default Environment
1228 CONFIG_EXTRA_ENV_SETTINGS
1230 Define this to contain any number of null terminated
1231 strings (variable = value pairs) that will be part of
1232 the default enviroment compiled into the boot image.
1234 For example, place something like this in your
1235 board's config file:
1237 #define CONFIG_EXTRA_ENV_SETTINGS \
1241 Warning: This method is based on knowledge about the
1242 internal format how the environment is stored by the
1243 U-Boot code. This is NOT an official, exported
1244 interface! Although it is unlikely that this format
1245 will change soon, but there is no guarantee either.
1246 You better know what you are doing here.
1248 Note: overly (ab)use of the default environment is
1249 discouraged. Make sure to check other ways to preset
1250 the environment like the autoscript function or the
1254 CONFIG_HAS_DATAFLASH
1256 Defining this option enables DataFlash features and
1257 allows to read/write in Dataflash via the standard
1260 - Show boot progress
1261 CONFIG_SHOW_BOOT_PROGRESS
1263 Defining this option allows to add some board-
1264 specific code (calling a user-provided function
1265 "show_boot_progress(int)") that enables you to show
1266 the system's boot progress on some display (for
1267 example, some LED's) on your board. At the moment,
1268 the following checkpoints are implemented:
1271 1 common/cmd_bootm.c before attempting to boot an image
1272 -1 common/cmd_bootm.c Image header has bad magic number
1273 2 common/cmd_bootm.c Image header has correct magic number
1274 -2 common/cmd_bootm.c Image header has bad checksum
1275 3 common/cmd_bootm.c Image header has correct checksum
1276 -3 common/cmd_bootm.c Image data has bad checksum
1277 4 common/cmd_bootm.c Image data has correct checksum
1278 -4 common/cmd_bootm.c Image is for unsupported architecture
1279 5 common/cmd_bootm.c Architecture check OK
1280 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1281 6 common/cmd_bootm.c Image Type check OK
1282 -6 common/cmd_bootm.c gunzip uncompression error
1283 -7 common/cmd_bootm.c Unimplemented compression type
1284 7 common/cmd_bootm.c Uncompression OK
1285 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1286 8 common/cmd_bootm.c Image Type check OK
1287 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1288 9 common/cmd_bootm.c Start initial ramdisk verification
1289 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1290 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1291 10 common/cmd_bootm.c Ramdisk header is OK
1292 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1293 11 common/cmd_bootm.c Ramdisk data has correct checksum
1294 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1295 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1296 13 common/cmd_bootm.c Start multifile image verification
1297 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1298 15 common/cmd_bootm.c All preparation done, transferring control to OS
1300 -1 common/cmd_doc.c Bad usage of "doc" command
1301 -1 common/cmd_doc.c No boot device
1302 -1 common/cmd_doc.c Unknown Chip ID on boot device
1303 -1 common/cmd_doc.c Read Error on boot device
1304 -1 common/cmd_doc.c Image header has bad magic number
1306 -1 common/cmd_ide.c Bad usage of "ide" command
1307 -1 common/cmd_ide.c No boot device
1308 -1 common/cmd_ide.c Unknown boot device
1309 -1 common/cmd_ide.c Unknown partition table
1310 -1 common/cmd_ide.c Invalid partition type
1311 -1 common/cmd_ide.c Read Error on boot device
1312 -1 common/cmd_ide.c Image header has bad magic number
1314 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1320 [so far only for SMDK2400 and TRAB boards]
1322 - Modem support endable:
1323 CONFIG_MODEM_SUPPORT
1325 - RTS/CTS Flow control enable:
1328 - Modem debug support:
1329 CONFIG_MODEM_SUPPORT_DEBUG
1331 Enables debugging stuff (char screen[1024], dbg())
1332 for modem support. Useful only with BDI2000.
1336 In the target system modem support is enabled when a
1337 specific key (key combination) is pressed during
1338 power-on. Otherwise U-Boot will boot normally
1339 (autoboot). The key_pressed() fuction is called from
1340 board_init(). Currently key_pressed() is a dummy
1341 function, returning 1 and thus enabling modem
1344 If there are no modem init strings in the
1345 environment, U-Boot proceed to autoboot; the
1346 previous output (banner, info printfs) will be
1349 See also: doc/README.Modem
1352 Configuration Settings:
1353 -----------------------
1355 - CFG_LONGHELP: Defined when you want long help messages included;
1356 undefine this when you're short of memory.
1358 - CFG_PROMPT: This is what U-Boot prints on the console to
1359 prompt for user input.
1361 - CFG_CBSIZE: Buffer size for input from the Console
1363 - CFG_PBSIZE: Buffer size for Console output
1365 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1367 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1368 the application (usually a Linux kernel) when it is
1371 - CFG_BAUDRATE_TABLE:
1372 List of legal baudrate settings for this board.
1374 - CFG_CONSOLE_INFO_QUIET
1375 Suppress display of console information at boot.
1377 - CFG_CONSOLE_IS_IN_ENV
1378 If the board specific function
1379 extern int overwrite_console (void);
1380 returns 1, the stdin, stderr and stdout are switched to the
1381 serial port, else the settings in the environment are used.
1383 - CFG_CONSOLE_OVERWRITE_ROUTINE
1384 Enable the call to overwrite_console().
1386 - CFG_CONSOLE_ENV_OVERWRITE
1387 Enable overwrite of previous console environment settings.
1389 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1390 Begin and End addresses of the area used by the
1394 Enable an alternate, more extensive memory test.
1396 - CFG_TFTP_LOADADDR:
1397 Default load address for network file downloads
1399 - CFG_LOADS_BAUD_CHANGE:
1400 Enable temporary baudrate change while serial download
1403 Physical start address of SDRAM. _Must_ be 0 here.
1406 Physical start address of Motherboard I/O (if using a
1410 Physical start address of Flash memory.
1413 Physical start address of boot monitor code (set by
1414 make config files to be same as the text base address
1415 (TEXT_BASE) used when linking) - same as
1416 CFG_FLASH_BASE when booting from flash.
1419 Size of memory reserved for monitor code, used to
1420 determine _at_compile_time_ (!) if the environment is
1421 embedded within the U-Boot image, or in a separate
1425 Size of DRAM reserved for malloc() use.
1428 Maximum size of memory mapped by the startup code of
1429 the Linux kernel; all data that must be processed by
1430 the Linux kernel (bd_info, boot arguments, eventually
1431 initrd image) must be put below this limit.
1433 - CFG_MAX_FLASH_BANKS:
1434 Max number of Flash memory banks
1436 - CFG_MAX_FLASH_SECT:
1437 Max number of sectors on a Flash chip
1439 - CFG_FLASH_ERASE_TOUT:
1440 Timeout for Flash erase operations (in ms)
1442 - CFG_FLASH_WRITE_TOUT:
1443 Timeout for Flash write operations (in ms)
1445 - CFG_DIRECT_FLASH_TFTP:
1447 Enable TFTP transfers directly to flash memory;
1448 without this option such a download has to be
1449 performed in two steps: (1) download to RAM, and (2)
1450 copy from RAM to flash.
1452 The two-step approach is usually more reliable, since
1453 you can check if the download worked before you erase
1454 the flash, but in some situations (when sytem RAM is
1455 too limited to allow for a tempory copy of the
1456 downloaded image) this option may be very useful.
1459 Define if the flash driver uses extra elements in the
1460 common flash structure for storing flash geometry
1462 - CFG_RX_ETH_BUFFER:
1463 Defines the number of ethernet receive buffers. On some
1464 ethernet controllers it is recommended to set this value
1465 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1466 buffers can be full shortly after enabling the interface
1467 on high ethernet traffic.
1468 Defaults to 4 if not defined.
1470 The following definitions that deal with the placement and management
1471 of environment data (variable area); in general, we support the
1472 following configurations:
1474 - CFG_ENV_IS_IN_FLASH:
1476 Define this if the environment is in flash memory.
1478 a) The environment occupies one whole flash sector, which is
1479 "embedded" in the text segment with the U-Boot code. This
1480 happens usually with "bottom boot sector" or "top boot
1481 sector" type flash chips, which have several smaller
1482 sectors at the start or the end. For instance, such a
1483 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1484 such a case you would place the environment in one of the
1485 4 kB sectors - with U-Boot code before and after it. With
1486 "top boot sector" type flash chips, you would put the
1487 environment in one of the last sectors, leaving a gap
1488 between U-Boot and the environment.
1492 Offset of environment data (variable area) to the
1493 beginning of flash memory; for instance, with bottom boot
1494 type flash chips the second sector can be used: the offset
1495 for this sector is given here.
1497 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1501 This is just another way to specify the start address of
1502 the flash sector containing the environment (instead of
1505 - CFG_ENV_SECT_SIZE:
1507 Size of the sector containing the environment.
1510 b) Sometimes flash chips have few, equal sized, BIG sectors.
1511 In such a case you don't want to spend a whole sector for
1516 If you use this in combination with CFG_ENV_IS_IN_FLASH
1517 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1518 of this flash sector for the environment. This saves
1519 memory for the RAM copy of the environment.
1521 It may also save flash memory if you decide to use this
1522 when your environment is "embedded" within U-Boot code,
1523 since then the remainder of the flash sector could be used
1524 for U-Boot code. It should be pointed out that this is
1525 STRONGLY DISCOURAGED from a robustness point of view:
1526 updating the environment in flash makes it always
1527 necessary to erase the WHOLE sector. If something goes
1528 wrong before the contents has been restored from a copy in
1529 RAM, your target system will be dead.
1531 - CFG_ENV_ADDR_REDUND
1534 These settings describe a second storage area used to hold
1535 a redundand copy of the environment data, so that there is
1536 a valid backup copy in case there is a power failure during
1537 a "saveenv" operation.
1539 BE CAREFUL! Any changes to the flash layout, and some changes to the
1540 source code will make it necessary to adapt <board>/u-boot.lds*
1544 - CFG_ENV_IS_IN_NVRAM:
1546 Define this if you have some non-volatile memory device
1547 (NVRAM, battery buffered SRAM) which you want to use for the
1553 These two #defines are used to determin the memory area you
1554 want to use for environment. It is assumed that this memory
1555 can just be read and written to, without any special
1558 BE CAREFUL! The first access to the environment happens quite early
1559 in U-Boot initalization (when we try to get the setting of for the
1560 console baudrate). You *MUST* have mappend your NVRAM area then, or
1563 Please note that even with NVRAM we still use a copy of the
1564 environment in RAM: we could work on NVRAM directly, but we want to
1565 keep settings there always unmodified except somebody uses "saveenv"
1566 to save the current settings.
1569 - CFG_ENV_IS_IN_EEPROM:
1571 Use this if you have an EEPROM or similar serial access
1572 device and a driver for it.
1577 These two #defines specify the offset and size of the
1578 environment area within the total memory of your EEPROM.
1580 - CFG_I2C_EEPROM_ADDR:
1581 If defined, specified the chip address of the EEPROM device.
1582 The default address is zero.
1584 - CFG_EEPROM_PAGE_WRITE_BITS:
1585 If defined, the number of bits used to address bytes in a
1586 single page in the EEPROM device. A 64 byte page, for example
1587 would require six bits.
1589 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1590 If defined, the number of milliseconds to delay between
1591 page writes. The default is zero milliseconds.
1593 - CFG_I2C_EEPROM_ADDR_LEN:
1594 The length in bytes of the EEPROM memory array address. Note
1595 that this is NOT the chip address length!
1598 The size in bytes of the EEPROM device.
1601 - CFG_SPI_INIT_OFFSET
1603 Defines offset to the initial SPI buffer area in DPRAM. The
1604 area is used at an early stage (ROM part) if the environment
1605 is configured to reside in the SPI EEPROM: We need a 520 byte
1606 scratch DPRAM area. It is used between the two initialization
1607 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1608 to be a good choice since it makes it far enough from the
1609 start of the data area as well as from the stack pointer.
1611 Please note that the environment is read-only as long as the monitor
1612 has been relocated to RAM and a RAM copy of the environment has been
1613 created; also, when using EEPROM you will have to use getenv_r()
1614 until then to read environment variables.
1616 The environment is protected by a CRC32 checksum. Before the monitor
1617 is relocated into RAM, as a result of a bad CRC you will be working
1618 with the compiled-in default environment - *silently*!!! [This is
1619 necessary, because the first environment variable we need is the
1620 "baudrate" setting for the console - if we have a bad CRC, we don't
1621 have any device yet where we could complain.]
1623 Note: once the monitor has been relocated, then it will complain if
1624 the default environment is used; a new CRC is computed as soon as you
1625 use the "saveenv" command to store a valid environment.
1628 Low Level (hardware related) configuration options:
1629 ---------------------------------------------------
1631 - CFG_CACHELINE_SIZE:
1632 Cache Line Size of the CPU.
1635 Default address of the IMMR after system reset.
1636 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1637 to be able to adjust the position of the IMMR
1638 register after a reset.
1640 - Floppy Disk Support:
1641 CFG_FDC_DRIVE_NUMBER
1643 the default drive number (default value 0)
1647 defines the spacing between fdc chipset registers
1652 defines the offset of register from address. It
1653 depends on which part of the data bus is connected to
1654 the fdc chipset. (default value 0)
1656 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1657 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1660 if CFG_FDC_HW_INIT is defined, then the function
1661 fdc_hw_init() is called at the beginning of the FDC
1662 setup. fdc_hw_init() must be provided by the board
1663 source code. It is used to make hardware dependant
1666 - CFG_IMMR: Physical address of the Internal Memory Mapped
1667 Register; DO NOT CHANGE! (11-4)
1668 [MPC8xx systems only]
1670 - CFG_INIT_RAM_ADDR:
1672 Start address of memory area tha can be used for
1673 initial data and stack; please note that this must be
1674 writable memory that is working WITHOUT special
1675 initialization, i. e. you CANNOT use normal RAM which
1676 will become available only after programming the
1677 memory controller and running certain initialization
1680 U-Boot uses the following memory types:
1681 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1682 - MPC824X: data cache
1683 - PPC4xx: data cache
1685 - CFG_GBL_DATA_OFFSET:
1687 Offset of the initial data structure in the memory
1688 area defined by CFG_INIT_RAM_ADDR. Usually
1689 CFG_GBL_DATA_OFFSET is chosen such that the initial
1690 data is located at the end of the available space
1691 (sometimes written as (CFG_INIT_RAM_END -
1692 CFG_INIT_DATA_SIZE), and the initial stack is just
1693 below that area (growing from (CFG_INIT_RAM_ADDR +
1694 CFG_GBL_DATA_OFFSET) downward.
1697 On the MPC824X (or other systems that use the data
1698 cache for initial memory) the address chosen for
1699 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1700 point to an otherwise UNUSED address space between
1701 the top of RAM and the start of the PCI space.
1703 - CFG_SIUMCR: SIU Module Configuration (11-6)
1705 - CFG_SYPCR: System Protection Control (11-9)
1707 - CFG_TBSCR: Time Base Status and Control (11-26)
1709 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1711 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1713 - CFG_SCCR: System Clock and reset Control Register (15-27)
1715 - CFG_OR_TIMING_SDRAM:
1719 periodic timer for refresh
1721 - CFG_DER: Debug Event Register (37-47)
1723 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1724 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1725 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1727 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1729 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1730 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1731 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1732 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1734 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1735 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1736 Machine Mode Register and Memory Periodic Timer
1737 Prescaler definitions (SDRAM timing)
1739 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1740 enable I2C microcode relocation patch (MPC8xx);
1741 define relocation offset in DPRAM [DSP2]
1743 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1744 enable SPI microcode relocation patch (MPC8xx);
1745 define relocation offset in DPRAM [SCC4]
1748 Use OSCM clock mode on MBX8xx board. Be careful,
1749 wrong setting might damage your board. Read
1750 doc/README.MBX before setting this variable!
1752 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1753 Offset of the bootmode word in DPRAM used by post
1754 (Power On Self Tests). This definition overrides
1755 #define'd default value in commproc.h resp.
1758 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1759 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1760 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1761 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1762 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1763 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1764 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1765 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1766 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1768 Building the Software:
1769 ======================
1771 Building U-Boot has been tested in native PPC environments (on a
1772 PowerBook G3 running LinuxPPC 2000) and in cross environments
1773 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1776 If you are not using a native PPC environment, it is assumed that you
1777 have the GNU cross compiling tools available in your path and named
1778 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1779 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1780 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1783 CROSS_COMPILE = ppc_4xx-
1786 U-Boot is intended to be simple to build. After installing the
1787 sources you must configure U-Boot for one specific board type. This
1792 where "NAME_config" is the name of one of the existing
1793 configurations; the following names are supported:
1795 ADCIOP_config GTH_config TQM850L_config
1796 ADS860_config IP860_config TQM855L_config
1797 AR405_config IVML24_config TQM860L_config
1798 CANBT_config IVMS8_config WALNUT405_config
1799 CPCI405_config LANTEC_config cogent_common_config
1800 CPCIISER4_config MBX_config cogent_mpc8260_config
1801 CU824_config MBX860T_config cogent_mpc8xx_config
1802 ESTEEM192E_config RPXlite_config hermes_config
1803 ETX094_config RPXsuper_config hymod_config
1804 FADS823_config SM850_config lwmon_config
1805 FADS850SAR_config SPD823TS_config pcu_e_config
1806 FADS860T_config SXNI855T_config rsdproto_config
1807 FPS850L_config Sandpoint8240_config sbc8260_config
1808 GENIETV_config TQM823L_config PIP405_config
1809 GEN860T_config EBONY_config FPS860L_config
1810 ELPT860_config cmi_mpc5xx_config NETVIA_config
1813 Note: for some board special configuration names may exist; check if
1814 additional information is available from the board vendor; for
1815 instance, the TQM8xxL systems run normally at 50 MHz and use a
1816 SCC for 10baseT ethernet; there are also systems with 80 MHz
1817 CPU clock, and an optional Fast Ethernet module is available
1818 for CPU's with FEC. You can select such additional "features"
1819 when chosing the configuration, i. e.
1822 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1824 make TQM860L_FEC_config
1825 - will configure for a TQM860L at 50MHz with FEC for ethernet
1827 make TQM860L_80MHz_config
1828 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1831 make TQM860L_FEC_80MHz_config
1832 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1834 make TQM823L_LCD_config
1835 - will configure for a TQM823L with U-Boot console on LCD
1837 make TQM823L_LCD_80MHz_config
1838 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1843 Finally, type "make all", and you should get some working U-Boot
1844 images ready for downlod to / installation on your system:
1846 - "u-boot.bin" is a raw binary image
1847 - "u-boot" is an image in ELF binary format
1848 - "u-boot.srec" is in Motorola S-Record format
1851 Please be aware that the Makefiles assume you are using GNU make, so
1852 for instance on NetBSD you might need to use "gmake" instead of
1856 If the system board that you have is not listed, then you will need
1857 to port U-Boot to your hardware platform. To do this, follow these
1860 1. Add a new configuration option for your board to the toplevel
1861 "Makefile" and to the "MAKEALL" script, using the existing
1862 entries as examples. Note that here and at many other places
1863 boards and other names are listed alphabetically sorted. Please
1865 2. Create a new directory to hold your board specific code. Add any
1866 files you need. In your board directory, you will need at least
1867 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1868 3. Create a new configuration file "include/configs/<board>.h" for
1870 3. If you're porting U-Boot to a new CPU, then also create a new
1871 directory to hold your CPU specific code. Add any files you need.
1872 4. Run "make <board>_config" with your new name.
1873 5. Type "make", and you should get a working "u-boot.srec" file
1874 to be installed on your target system.
1875 6. Debug and solve any problems that might arise.
1876 [Of course, this last step is much harder than it sounds.]
1879 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1880 ==============================================================
1882 If you have modified U-Boot sources (for instance added a new board
1883 or support for new devices, a new CPU, etc.) you are expected to
1884 provide feedback to the other developers. The feedback normally takes
1885 the form of a "patch", i. e. a context diff against a certain (latest
1886 official or latest in CVS) version of U-Boot sources.
1888 But before you submit such a patch, please verify that your modifi-
1889 cation did not break existing code. At least make sure that *ALL* of
1890 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1891 just run the "MAKEALL" script, which will configure and build U-Boot
1892 for ALL supported system. Be warned, this will take a while. You can
1893 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1894 environment variable to the script, i. e. to use the cross tools from
1895 MontaVista's Hard Hat Linux you can type
1897 CROSS_COMPILE=ppc_8xx- MAKEALL
1899 or to build on a native PowerPC system you can type
1901 CROSS_COMPILE=' ' MAKEALL
1903 See also "U-Boot Porting Guide" below.
1906 Monitor Commands - Overview:
1907 ============================
1909 go - start application at address 'addr'
1910 run - run commands in an environment variable
1911 bootm - boot application image from memory
1912 bootp - boot image via network using BootP/TFTP protocol
1913 tftpboot- boot image via network using TFTP protocol
1914 and env variables "ipaddr" and "serverip"
1915 (and eventually "gatewayip")
1916 rarpboot- boot image via network using RARP/TFTP protocol
1917 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1918 loads - load S-Record file over serial line
1919 loadb - load binary file over serial line (kermit mode)
1921 mm - memory modify (auto-incrementing)
1922 nm - memory modify (constant address)
1923 mw - memory write (fill)
1925 cmp - memory compare
1926 crc32 - checksum calculation
1927 imd - i2c memory display
1928 imm - i2c memory modify (auto-incrementing)
1929 inm - i2c memory modify (constant address)
1930 imw - i2c memory write (fill)
1931 icrc32 - i2c checksum calculation
1932 iprobe - probe to discover valid I2C chip addresses
1933 iloop - infinite loop on address range
1934 isdram - print SDRAM configuration information
1935 sspi - SPI utility commands
1936 base - print or set address offset
1937 printenv- print environment variables
1938 setenv - set environment variables
1939 saveenv - save environment variables to persistent storage
1940 protect - enable or disable FLASH write protection
1941 erase - erase FLASH memory
1942 flinfo - print FLASH memory information
1943 bdinfo - print Board Info structure
1944 iminfo - print header information for application image
1945 coninfo - print console devices and informations
1946 ide - IDE sub-system
1947 loop - infinite loop on address range
1948 mtest - simple RAM test
1949 icache - enable or disable instruction cache
1950 dcache - enable or disable data cache
1951 reset - Perform RESET of the CPU
1952 echo - echo args to console
1953 version - print monitor version
1954 help - print online help
1955 ? - alias for 'help'
1958 Monitor Commands - Detailed Description:
1959 ========================================
1963 For now: just type "help <command>".
1966 Environment Variables:
1967 ======================
1969 U-Boot supports user configuration using Environment Variables which
1970 can be made persistent by saving to Flash memory.
1972 Environment Variables are set using "setenv", printed using
1973 "printenv", and saved to Flash using "saveenv". Using "setenv"
1974 without a value can be used to delete a variable from the
1975 environment. As long as you don't save the environment you are
1976 working with an in-memory copy. In case the Flash area containing the
1977 environment is erased by accident, a default environment is provided.
1979 Some configuration options can be set using Environment Variables:
1981 baudrate - see CONFIG_BAUDRATE
1983 bootdelay - see CONFIG_BOOTDELAY
1985 bootcmd - see CONFIG_BOOTCOMMAND
1987 bootargs - Boot arguments when booting an RTOS image
1989 bootfile - Name of the image to load with TFTP
1991 autoload - if set to "no" (any string beginning with 'n'),
1992 "bootp" will just load perform a lookup of the
1993 configuration from the BOOTP server, but not try to
1994 load any image using TFTP
1996 autostart - if set to "yes", an image loaded using the "bootp",
1997 "rarpboot", "tftpboot" or "diskboot" commands will
1998 be automatically started (by internally calling
2001 If set to "no", a standalone image passed to the
2002 "bootm" command will be copied to the load address
2003 (and eventually uncompressed), but NOT be started.
2004 This can be used to load and uncompress arbitrary
2007 initrd_high - restrict positioning of initrd images:
2008 If this variable is not set, initrd images will be
2009 copied to the highest possible address in RAM; this
2010 is usually what you want since it allows for
2011 maximum initrd size. If for some reason you want to
2012 make sure that the initrd image is loaded below the
2013 CFG_BOOTMAPSZ limit, you can set this environment
2014 variable to a value of "no" or "off" or "0".
2015 Alternatively, you can set it to a maximum upper
2016 address to use (U-Boot will still check that it
2017 does not overwrite the U-Boot stack and data).
2019 For instance, when you have a system with 16 MB
2020 RAM, and want to reseve 4 MB from use by Linux,
2021 you can do this by adding "mem=12M" to the value of
2022 the "bootargs" variable. However, now you must make
2023 sure, that the initrd image is placed in the first
2024 12 MB as well - this can be done with
2026 setenv initrd_high 00c00000
2028 If you set initrd_high to 0xFFFFFFFF, this is an
2029 indication to U-Boot that all addresses are legal
2030 for the Linux kernel, including addresses in flash
2031 memory. In this case U-Boot will NOT COPY the
2032 ramdisk at all. This may be useful to reduce the
2033 boot time on your system, but requires that this
2034 feature is supported by your Linux kernel.
2036 ipaddr - IP address; needed for tftpboot command
2038 loadaddr - Default load address for commands like "bootp",
2039 "rarpboot", "tftpboot", "loadb" or "diskboot"
2041 loads_echo - see CONFIG_LOADS_ECHO
2043 serverip - TFTP server IP address; needed for tftpboot command
2045 bootretry - see CONFIG_BOOT_RETRY_TIME
2047 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2049 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2052 The following environment variables may be used and automatically
2053 updated by the network boot commands ("bootp" and "rarpboot"),
2054 depending the information provided by your boot server:
2056 bootfile - see above
2057 dnsip - IP address of your Domain Name Server
2058 gatewayip - IP address of the Gateway (Router) to use
2059 hostname - Target hostname
2061 netmask - Subnet Mask
2062 rootpath - Pathname of the root filesystem on the NFS server
2063 serverip - see above
2066 There are two special Environment Variables:
2068 serial# - contains hardware identification information such
2069 as type string and/or serial number
2070 ethaddr - Ethernet address
2072 These variables can be set only once (usually during manufacturing of
2073 the board). U-Boot refuses to delete or overwrite these variables
2074 once they have been set once.
2077 Further special Environment Variables:
2079 ver - Contains the U-Boot version string as printed
2080 with the "version" command. This variable is
2081 readonly (see CONFIG_VERSION_VARIABLE).
2084 Please note that changes to some configuration parameters may take
2085 only effect after the next boot (yes, that's just like Windoze :-).
2088 Command Line Parsing:
2089 =====================
2091 There are two different command line parsers available with U-Boot:
2092 the old "simple" one, and the much more pwerful "hush" shell:
2094 Old, simple command line parser:
2095 --------------------------------
2097 - supports environment variables (through setenv / saveenv commands)
2098 - several commands on one line, separated by ';'
2099 - variable substitution using "... $(name) ..." syntax
2100 - special characters ('$', ';') can be escaped by prefixing with '\',
2102 setenv bootcmd bootm \$(address)
2103 - You can also escape text by enclosing in single apostrophes, for example:
2104 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2109 - similar to Bourne shell, with control structures like
2110 if...then...else...fi, for...do...done; while...do...done,
2111 until...do...done, ...
2112 - supports environment ("global") variables (through setenv / saveenv
2113 commands) and local shell variables (through standard shell syntax
2114 "name=value"); only environment variables can be used with "run"
2120 (1) If a command line (or an environment variable executed by a "run"
2121 command) contains several commands separated by semicolon, and
2122 one of these commands fails, then the remaining commands will be
2125 (2) If you execute several variables with one call to run (i. e.
2126 calling run with a list af variables as arguments), any failing
2127 command will cause "run" to terminate, i. e. the remaining
2128 variables are not executed.
2130 Note for Redundant Ethernet Interfaces:
2131 =======================================
2133 Some boards come with redundand ethernet interfaces; U-Boot supports
2134 such configurations and is capable of automatic selection of a
2135 "working" interface when needed. MAC assignemnt works as follows:
2137 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2138 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2139 "eth1addr" (=>eth1), "eth2addr", ...
2141 If the network interface stores some valid MAC address (for instance
2142 in SROM), this is used as default address if there is NO correspon-
2143 ding setting in the environment; if the corresponding environment
2144 variable is set, this overrides the settings in the card; that means:
2146 o If the SROM has a valid MAC address, and there is no address in the
2147 environment, the SROM's address is used.
2149 o If there is no valid address in the SROM, and a definition in the
2150 environment exists, then the value from the environment variable is
2153 o If both the SROM and the environment contain a MAC address, and
2154 both addresses are the same, this MAC address is used.
2156 o If both the SROM and the environment contain a MAC address, and the
2157 addresses differ, the value from the environment is used and a
2160 o If neither SROM nor the environment contain a MAC address, an error
2167 The "boot" commands of this monitor operate on "image" files which
2168 can be basicly anything, preceeded by a special header; see the
2169 definitions in include/image.h for details; basicly, the header
2170 defines the following image properties:
2172 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2173 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2174 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2175 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
2176 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2177 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2178 Currently supported: PowerPC).
2179 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2180 Currently supported: uncompressed, gzip).
2186 The header is marked by a special Magic Number, and both the header
2187 and the data portions of the image are secured against corruption by
2194 Although U-Boot should support any OS or standalone application
2195 easily, Linux has always been in the focus during the design of
2198 U-Boot includes many features that so far have been part of some
2199 special "boot loader" code within the Linux kernel. Also, any
2200 "initrd" images to be used are no longer part of one big Linux image;
2201 instead, kernel and "initrd" are separate images. This implementation
2202 serves serveral purposes:
2204 - the same features can be used for other OS or standalone
2205 applications (for instance: using compressed images to reduce the
2206 Flash memory footprint)
2208 - it becomes much easier to port new Linux kernel versions because
2209 lots of low-level, hardware dependend stuff are done by U-Boot
2211 - the same Linux kernel image can now be used with different "initrd"
2212 images; of course this also means that different kernel images can
2213 be run with the same "initrd". This makes testing easier (you don't
2214 have to build a new "zImage.initrd" Linux image when you just
2215 change a file in your "initrd"). Also, a field-upgrade of the
2216 software is easier now.
2222 Porting Linux to U-Boot based systems:
2223 ---------------------------------------
2225 U-Boot cannot save you from doing all the necessary modifications to
2226 configure the Linux device drivers for use with your target hardware
2227 (no, we don't intend to provide a full virtual machine interface to
2230 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2232 Just make sure your machine specific header file (for instance
2233 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2234 Information structure as we define in include/u-boot.h, and make
2235 sure that your definition of IMAP_ADDR uses the same value as your
2236 U-Boot configuration in CFG_IMMR.
2239 Configuring the Linux kernel:
2240 -----------------------------
2242 No specific requirements for U-Boot. Make sure you have some root
2243 device (initial ramdisk, NFS) for your target system.
2246 Building a Linux Image:
2247 -----------------------
2249 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2250 not used. If you use recent kernel source, a new build target
2251 "uImage" will exist which automatically builds an image usable by
2252 U-Boot. Most older kernels also have support for a "pImage" target,
2253 which was introduced for our predecessor project PPCBoot and uses a
2254 100% compatible format.
2263 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2264 encapsulate a compressed Linux kernel image with header information,
2265 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2267 * build a standard "vmlinux" kernel image (in ELF binary format):
2269 * convert the kernel into a raw binary image:
2271 ${CROSS_COMPILE}-objcopy -O binary \
2272 -R .note -R .comment \
2273 -S vmlinux linux.bin
2275 * compress the binary image:
2279 * package compressed binary image for U-Boot:
2281 mkimage -A ppc -O linux -T kernel -C gzip \
2282 -a 0 -e 0 -n "Linux Kernel Image" \
2283 -d linux.bin.gz uImage
2286 The "mkimage" tool can also be used to create ramdisk images for use
2287 with U-Boot, either separated from the Linux kernel image, or
2288 combined into one file. "mkimage" encapsulates the images with a 64
2289 byte header containing information about target architecture,
2290 operating system, image type, compression method, entry points, time
2291 stamp, CRC32 checksums, etc.
2293 "mkimage" can be called in two ways: to verify existing images and
2294 print the header information, or to build new images.
2296 In the first form (with "-l" option) mkimage lists the information
2297 contained in the header of an existing U-Boot image; this includes
2298 checksum verification:
2300 tools/mkimage -l image
2301 -l ==> list image header information
2303 The second form (with "-d" option) is used to build a U-Boot image
2304 from a "data file" which is used as image payload:
2306 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2307 -n name -d data_file image
2308 -A ==> set architecture to 'arch'
2309 -O ==> set operating system to 'os'
2310 -T ==> set image type to 'type'
2311 -C ==> set compression type 'comp'
2312 -a ==> set load address to 'addr' (hex)
2313 -e ==> set entry point to 'ep' (hex)
2314 -n ==> set image name to 'name'
2315 -d ==> use image data from 'datafile'
2317 Right now, all Linux kernels use the same load address (0x00000000),
2318 but the entry point address depends on the kernel version:
2320 - 2.2.x kernels have the entry point at 0x0000000C,
2321 - 2.3.x and later kernels have the entry point at 0x00000000.
2323 So a typical call to build a U-Boot image would read:
2325 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2326 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2327 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2328 > examples/uImage.TQM850L
2329 Image Name: 2.4.4 kernel for TQM850L
2330 Created: Wed Jul 19 02:34:59 2000
2331 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2332 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2333 Load Address: 0x00000000
2334 Entry Point: 0x00000000
2336 To verify the contents of the image (or check for corruption):
2338 -> tools/mkimage -l examples/uImage.TQM850L
2339 Image Name: 2.4.4 kernel for TQM850L
2340 Created: Wed Jul 19 02:34:59 2000
2341 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2342 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2343 Load Address: 0x00000000
2344 Entry Point: 0x00000000
2346 NOTE: for embedded systems where boot time is critical you can trade
2347 speed for memory and install an UNCOMPRESSED image instead: this
2348 needs more space in Flash, but boots much faster since it does not
2349 need to be uncompressed:
2351 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2352 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2353 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2354 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2355 > examples/uImage.TQM850L-uncompressed
2356 Image Name: 2.4.4 kernel for TQM850L
2357 Created: Wed Jul 19 02:34:59 2000
2358 Image Type: PowerPC Linux Kernel Image (uncompressed)
2359 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2360 Load Address: 0x00000000
2361 Entry Point: 0x00000000
2364 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2365 when your kernel is intended to use an initial ramdisk:
2367 -> tools/mkimage -n 'Simple Ramdisk Image' \
2368 > -A ppc -O linux -T ramdisk -C gzip \
2369 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2370 Image Name: Simple Ramdisk Image
2371 Created: Wed Jan 12 14:01:50 2000
2372 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2373 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2374 Load Address: 0x00000000
2375 Entry Point: 0x00000000
2378 Installing a Linux Image:
2379 -------------------------
2381 To downloading a U-Boot image over the serial (console) interface,
2382 you must convert the image to S-Record format:
2384 objcopy -I binary -O srec examples/image examples/image.srec
2386 The 'objcopy' does not understand the information in the U-Boot
2387 image header, so the resulting S-Record file will be relative to
2388 address 0x00000000. To load it to a given address, you need to
2389 specify the target address as 'offset' parameter with the 'loads'
2392 Example: install the image to address 0x40100000 (which on the
2393 TQM8xxL is in the first Flash bank):
2395 => erase 40100000 401FFFFF
2401 ## Ready for S-Record download ...
2402 ~>examples/image.srec
2403 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2405 15989 15990 15991 15992
2406 [file transfer complete]
2408 ## Start Addr = 0x00000000
2411 You can check the success of the download using the 'iminfo' command;
2412 this includes a checksum verification so you can be sure no data
2413 corruption happened:
2417 ## Checking Image at 40100000 ...
2418 Image Name: 2.2.13 for initrd on TQM850L
2419 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2420 Data Size: 335725 Bytes = 327 kB = 0 MB
2421 Load Address: 00000000
2422 Entry Point: 0000000c
2423 Verifying Checksum ... OK
2429 The "bootm" command is used to boot an application that is stored in
2430 memory (RAM or Flash). In case of a Linux kernel image, the contents
2431 of the "bootargs" environment variable is passed to the kernel as
2432 parameters. You can check and modify this variable using the
2433 "printenv" and "setenv" commands:
2436 => printenv bootargs
2437 bootargs=root=/dev/ram
2439 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2441 => printenv bootargs
2442 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2445 ## Booting Linux kernel at 40020000 ...
2446 Image Name: 2.2.13 for NFS on TQM850L
2447 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2448 Data Size: 381681 Bytes = 372 kB = 0 MB
2449 Load Address: 00000000
2450 Entry Point: 0000000c
2451 Verifying Checksum ... OK
2452 Uncompressing Kernel Image ... OK
2453 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
2454 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2455 time_init: decrementer frequency = 187500000/60
2456 Calibrating delay loop... 49.77 BogoMIPS
2457 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2460 If you want to boot a Linux kernel with initial ram disk, you pass
2461 the memory addreses of both the kernel and the initrd image (PPBCOOT
2462 format!) to the "bootm" command:
2464 => imi 40100000 40200000
2466 ## Checking Image at 40100000 ...
2467 Image Name: 2.2.13 for initrd on TQM850L
2468 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2469 Data Size: 335725 Bytes = 327 kB = 0 MB
2470 Load Address: 00000000
2471 Entry Point: 0000000c
2472 Verifying Checksum ... OK
2474 ## Checking Image at 40200000 ...
2475 Image Name: Simple Ramdisk Image
2476 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2477 Data Size: 566530 Bytes = 553 kB = 0 MB
2478 Load Address: 00000000
2479 Entry Point: 00000000
2480 Verifying Checksum ... OK
2482 => bootm 40100000 40200000
2483 ## Booting Linux kernel at 40100000 ...
2484 Image Name: 2.2.13 for initrd on TQM850L
2485 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2486 Data Size: 335725 Bytes = 327 kB = 0 MB
2487 Load Address: 00000000
2488 Entry Point: 0000000c
2489 Verifying Checksum ... OK
2490 Uncompressing Kernel Image ... OK
2491 ## Loading RAMDisk Image at 40200000 ...
2492 Image Name: Simple Ramdisk Image
2493 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2494 Data Size: 566530 Bytes = 553 kB = 0 MB
2495 Load Address: 00000000
2496 Entry Point: 00000000
2497 Verifying Checksum ... OK
2498 Loading Ramdisk ... OK
2499 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
2500 Boot arguments: root=/dev/ram
2501 time_init: decrementer frequency = 187500000/60
2502 Calibrating delay loop... 49.77 BogoMIPS
2504 RAMDISK: Compressed image found at block 0
2505 VFS: Mounted root (ext2 filesystem).
2509 More About U-Boot Image Types:
2510 ------------------------------
2512 U-Boot supports the following image types:
2514 "Standalone Programs" are directly runnable in the environment
2515 provided by U-Boot; it is expected that (if they behave
2516 well) you can continue to work in U-Boot after return from
2517 the Standalone Program.
2518 "OS Kernel Images" are usually images of some Embedded OS which
2519 will take over control completely. Usually these programs
2520 will install their own set of exception handlers, device
2521 drivers, set up the MMU, etc. - this means, that you cannot
2522 expect to re-enter U-Boot except by resetting the CPU.
2523 "RAMDisk Images" are more or less just data blocks, and their
2524 parameters (address, size) are passed to an OS kernel that is
2526 "Multi-File Images" contain several images, typically an OS
2527 (Linux) kernel image and one or more data images like
2528 RAMDisks. This construct is useful for instance when you want
2529 to boot over the network using BOOTP etc., where the boot
2530 server provides just a single image file, but you want to get
2531 for instance an OS kernel and a RAMDisk image.
2533 "Multi-File Images" start with a list of image sizes, each
2534 image size (in bytes) specified by an "uint32_t" in network
2535 byte order. This list is terminated by an "(uint32_t)0".
2536 Immediately after the terminating 0 follow the images, one by
2537 one, all aligned on "uint32_t" boundaries (size rounded up to
2538 a multiple of 4 bytes).
2540 "Firmware Images" are binary images containing firmware (like
2541 U-Boot or FPGA images) which usually will be programmed to
2544 "Script files" are command sequences that will be executed by
2545 U-Boot's command interpreter; this feature is especially
2546 useful when you configure U-Boot to use a real shell (hush)
2547 as command interpreter.
2553 One of the features of U-Boot is that you can dynamically load and
2554 run "standalone" applications, which can use some resources of
2555 U-Boot like console I/O functions or interrupt services.
2557 Two simple examples are included with the sources:
2562 'examples/hello_world.c' contains a small "Hello World" Demo
2563 application; it is automatically compiled when you build U-Boot.
2564 It's configured to run at address 0x00040004, so you can play with it
2568 ## Ready for S-Record download ...
2569 ~>examples/hello_world.srec
2570 1 2 3 4 5 6 7 8 9 10 11 ...
2571 [file transfer complete]
2573 ## Start Addr = 0x00040004
2575 => go 40004 Hello World! This is a test.
2576 ## Starting application at 0x00040004 ...
2587 Hit any key to exit ...
2589 ## Application terminated, rc = 0x0
2591 Another example, which demonstrates how to register a CPM interrupt
2592 handler with the U-Boot code, can be found in 'examples/timer.c'.
2593 Here, a CPM timer is set up to generate an interrupt every second.
2594 The interrupt service routine is trivial, just printing a '.'
2595 character, but this is just a demo program. The application can be
2596 controlled by the following keys:
2598 ? - print current values og the CPM Timer registers
2599 b - enable interrupts and start timer
2600 e - stop timer and disable interrupts
2601 q - quit application
2604 ## Ready for S-Record download ...
2605 ~>examples/timer.srec
2606 1 2 3 4 5 6 7 8 9 10 11 ...
2607 [file transfer complete]
2609 ## Start Addr = 0x00040004
2612 ## Starting application at 0x00040004 ...
2615 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2618 [q, b, e, ?] Set interval 1000000 us
2621 [q, b, e, ?] ........
2622 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2625 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2628 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2631 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2633 [q, b, e, ?] ...Stopping timer
2635 [q, b, e, ?] ## Application terminated, rc = 0x0
2641 Over time, many people have reported problems when trying to used the
2642 "minicom" terminal emulation program for serial download. I (wd)
2643 consider minicom to be broken, and recommend not to use it. Under
2644 Unix, I recommend to use C-Kermit for general purpose use (and
2645 especially for kermit binary protocol download ("loadb" command), and
2646 use "cu" for S-Record download ("loads" command).
2648 Nevertheless, if you absolutely want to use it try adding this
2649 configuration to your "File transfer protocols" section:
2651 Name Program Name U/D FullScr IO-Red. Multi
2652 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2653 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2659 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2660 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2662 Building requires a cross environment; it is known to work on
2663 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2664 need gmake since the Makefiles are not compatible with BSD make).
2665 Note that the cross-powerpc package does not install include files;
2666 attempting to build U-Boot will fail because <machine/ansi.h> is
2667 missing. This file has to be installed and patched manually:
2669 # cd /usr/pkg/cross/powerpc-netbsd/include
2671 # ln -s powerpc machine
2672 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2673 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2675 Native builds *don't* work due to incompatibilities between native
2676 and U-Boot include files.
2678 Booting assumes that (the first part of) the image booted is a
2679 stage-2 loader which in turn loads and then invokes the kernel
2680 proper. Loader sources will eventually appear in the NetBSD source
2681 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2682 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2686 Implementation Internals:
2687 =========================
2689 The following is not intended to be a complete description of every
2690 implementation detail. However, it should help to understand the
2691 inner workings of U-Boot and make it easier to port it to custom
2695 Initial Stack, Global Data:
2696 ---------------------------
2698 The implementation of U-Boot is complicated by the fact that U-Boot
2699 starts running out of ROM (flash memory), usually without access to
2700 system RAM (because the memory controller is not initialized yet).
2701 This means that we don't have writable Data or BSS segments, and BSS
2702 is not initialized as zero. To be able to get a C environment working
2703 at all, we have to allocate at least a minimal stack. Implementation
2704 options for this are defined and restricted by the CPU used: Some CPU
2705 models provide on-chip memory (like the IMMR area on MPC8xx and
2706 MPC826x processors), on others (parts of) the data cache can be
2707 locked as (mis-) used as memory, etc.
2709 Chris Hallinan posted a good summy of these issues to the
2710 u-boot-users mailing list:
2712 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2713 From: "Chris Hallinan" <clh@net1plus.com>
2714 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2717 Correct me if I'm wrong, folks, but the way I understand it
2718 is this: Using DCACHE as initial RAM for Stack, etc, does not
2719 require any physical RAM backing up the cache. The cleverness
2720 is that the cache is being used as a temporary supply of
2721 necessary storage before the SDRAM controller is setup. It's
2722 beyond the scope of this list to expain the details, but you
2723 can see how this works by studying the cache architecture and
2724 operation in the architecture and processor-specific manuals.
2726 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2727 is another option for the system designer to use as an
2728 initial stack/ram area prior to SDRAM being available. Either
2729 option should work for you. Using CS 4 should be fine if your
2730 board designers haven't used it for something that would
2731 cause you grief during the initial boot! It is frequently not
2734 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2735 with your processor/board/system design. The default value
2736 you will find in any recent u-boot distribution in
2737 Walnut405.h should work for you. I'd set it to a value larger
2738 than your SDRAM module. If you have a 64MB SDRAM module, set
2739 it above 400_0000. Just make sure your board has no resources
2740 that are supposed to respond to that address! That code in
2741 start.S has been around a while and should work as is when
2742 you get the config right.
2747 It is essential to remember this, since it has some impact on the C
2748 code for the initialization procedures:
2750 * Initialized global data (data segment) is read-only. Do not attempt
2753 * Do not use any unitialized global data (or implicitely initialized
2754 as zero data - BSS segment) at all - this is undefined, initiali-
2755 zation is performed later (when relocationg to RAM).
2757 * Stack space is very limited. Avoid big data buffers or things like
2760 Having only the stack as writable memory limits means we cannot use
2761 normal global data to share information beween the code. But it
2762 turned out that the implementation of U-Boot can be greatly
2763 simplified by making a global data structure (gd_t) available to all
2764 functions. We could pass a pointer to this data as argument to _all_
2765 functions, but this would bloat the code. Instead we use a feature of
2766 the GCC compiler (Global Register Variables) to share the data: we
2767 place a pointer (gd) to the global data into a register which we
2768 reserve for this purpose.
2770 When chosing a register for such a purpose we are restricted by the
2771 relevant (E)ABI specifications for the current architecture, and by
2772 GCC's implementation.
2774 For PowerPC, the following registers have specific use:
2777 R3-R4: parameter passing and return values
2778 R5-R10: parameter passing
2779 R13: small data area pointer
2783 (U-Boot also uses R14 as internal GOT pointer.)
2785 ==> U-Boot will use R29 to hold a pointer to the global data
2787 Note: on PPC, we could use a static initializer (since the
2788 address of the global data structure is known at compile time),
2789 but it turned out that reserving a register results in somewhat
2790 smaller code - although the code savings are not that big (on
2791 average for all boards 752 bytes for the whole U-Boot image,
2792 624 text + 127 data).
2794 On ARM, the following registers are used:
2796 R0: function argument word/integer result
2797 R1-R3: function argument word
2799 R10: stack limit (used only if stack checking if enabled)
2800 R11: argument (frame) pointer
2801 R12: temporary workspace
2804 R15: program counter
2806 ==> U-Boot will use R8 to hold a pointer to the global data
2812 U-Boot runs in system state and uses physical addresses, i.e. the
2813 MMU is not used either for address mapping nor for memory protection.
2815 The available memory is mapped to fixed addresses using the memory
2816 controller. In this process, a contiguous block is formed for each
2817 memory type (Flash, SDRAM, SRAM), even when it consists of several
2818 physical memory banks.
2820 U-Boot is installed in the first 128 kB of the first Flash bank (on
2821 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2822 booting and sizing and initializing DRAM, the code relocates itself
2823 to the upper end of DRAM. Immediately below the U-Boot code some
2824 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2825 configuration setting]. Below that, a structure with global Board
2826 Info data is placed, followed by the stack (growing downward).
2828 Additionally, some exception handler code is copied to the low 8 kB
2829 of DRAM (0x00000000 ... 0x00001FFF).
2831 So a typical memory configuration with 16 MB of DRAM could look like
2834 0x0000 0000 Exception Vector code
2837 0x0000 2000 Free for Application Use
2843 0x00FB FF20 Monitor Stack (Growing downward)
2844 0x00FB FFAC Board Info Data and permanent copy of global data
2845 0x00FC 0000 Malloc Arena
2848 0x00FE 0000 RAM Copy of Monitor Code
2849 ... eventually: LCD or video framebuffer
2850 ... eventually: pRAM (Protected RAM - unchanged by reset)
2851 0x00FF FFFF [End of RAM]
2854 System Initialization:
2855 ----------------------
2857 In the reset configuration, U-Boot starts at the reset entry point
2858 (on most PowerPC systens at address 0x00000100). Because of the reset
2859 configuration for CS0# this is a mirror of the onboard Flash memory.
2860 To be able to re-map memory U-Boot then jumps to it's link address.
2861 To be able to implement the initialization code in C, a (small!)
2862 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2863 which provide such a feature like MPC8xx or MPC8260), or in a locked
2864 part of the data cache. After that, U-Boot initializes the CPU core,
2865 the caches and the SIU.
2867 Next, all (potentially) available memory banks are mapped using a
2868 preliminary mapping. For example, we put them on 512 MB boundaries
2869 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2870 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2871 programmed for SDRAM access. Using the temporary configuration, a
2872 simple memory test is run that determines the size of the SDRAM
2875 When there is more than one SDRAM bank, and the banks are of
2876 different size, the larger is mapped first. For equal size, the first
2877 bank (CS2#) is mapped first. The first mapping is always for address
2878 0x00000000, with any additional banks following immediately to create
2879 contiguous memory starting from 0.
2881 Then, the monitor installs itself at the upper end of the SDRAM area
2882 and allocates memory for use by malloc() and for the global Board
2883 Info data; also, the exception vector code is copied to the low RAM
2884 pages, and the final stack is set up.
2886 Only after this relocation will you have a "normal" C environment;
2887 until that you are restricted in several ways, mostly because you are
2888 running from ROM, and because the code will have to be relocated to a
2892 U-Boot Porting Guide:
2893 ----------------------
2895 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2899 int main (int argc, char *argv[])
2901 sighandler_t no_more_time;
2903 signal (SIGALRM, no_more_time);
2904 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2906 if (available_money > available_manpower) {
2907 pay consultant to port U-Boot;
2911 Download latest U-Boot source;
2913 Subscribe to u-boot-users mailing list;
2916 email ("Hi, I am new to U-Boot, how do I get started?");
2920 Read the README file in the top level directory;
2921 Read http://www.denx.de/re/DPLG.html
2922 Read the source, Luke;
2925 if (available_money > toLocalCurrency ($2500)) {
2928 Add a lot of aggravation and time;
2931 Create your own board support subdirectory;
2933 Create your own board config file;
2937 Add / modify source code;
2941 email ("Hi, I am having problems...");
2943 Send patch file to Wolfgang;
2948 void no_more_time (int sig)
2957 All contributions to U-Boot should conform to the Linux kernel
2958 coding style; see the file "Documentation/CodingStyle" in your Linux
2959 kernel source directory.
2961 Please note that U-Boot is implemented in C (and to some small parts
2962 in Assembler); no C++ is used, so please do not use C++ style
2963 comments (//) in your code.
2965 Submissions which do not conform to the standards may be returned
2966 with a request to reformat the changes.
2972 Since the number of patches for U-Boot is growing, we need to
2973 establish some rules. Submissions which do not conform to these rules
2974 may be rejected, even when they contain important and valuable stuff.
2977 When you send a patch, please include the following information with
2980 * For bug fixes: a description of the bug and how your patch fixes
2981 this bug. Please try to include a way of demonstrating that the
2982 patch actually fixes something.
2984 * For new features: a description of the feature and your
2987 * A CHANGELOG entry as plaintext (separate from the patch)
2989 * For major contributions, your entry to the CREDITS file
2991 * When you add support for a new board, don't forget to add this
2992 board to the MAKEALL script, too.
2994 * If your patch adds new configuration options, don't forget to
2995 document these in the README file.
2997 * The patch itself. If you are accessing the CVS repository use "cvs
2998 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2999 version of diff does not support these options, then get the latest
3000 version of GNU diff.
3002 We accept patches as plain text, MIME attachments or as uuencoded
3005 * If one logical set of modifications affects or creates several
3006 files, all these changes shall be submitted in a SINGLE patch file.
3008 * Changesets that contain different, unrelated modifications shall be
3009 submitted as SEPARATE patches, one patch per changeset.
3014 * Before sending the patch, run the MAKEALL script on your patched
3015 source tree and make sure that no errors or warnings are reported
3016 for any of the boards.
3018 * Keep your modifications to the necessary minimum: A patch
3019 containing several unrelated changes or arbitrary reformats will be
3020 returned with a request to re-formatting / split it.
3022 * If you modify existing code, make sure that your new code does not
3023 add to the memory footprint of the code ;-) Small is beautiful!
3024 When adding new features, these should compile conditionally only
3025 (using #ifdef), and the resulting code with the new feature
3026 disabled must not need more memory than the old code without your
projects / u-boot.git / blob