2 # (C) Copyright 2000 - 2002
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
62 previous traffic on the mailing list - please search the archive
63 before asking FAQ's. Please see
64 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
70 - start from 8xxrom sources
71 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
73 - make it easier to add custom boards
74 - make it possible to add other [PowerPC] CPUs
75 - extend functions, especially:
76 * Provide extended interface to Linux boot loader
79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80 - create ARMBoot project (http://sourceforge.net/projects/armboot)
81 - add other CPU families (starting with ARM)
82 - create U-Boot project (http://sourceforge.net/projects/u-boot)
88 The "official" name of this project is "Das U-Boot". The spelling
89 "U-Boot" shall be used in all written text (documentation, comments
90 in source files etc.). Example:
92 This is the README file for the U-Boot project.
94 File names etc. shall be based on the string "u-boot". Examples:
96 include/asm-ppc/u-boot.h
98 #include <asm/u-boot.h>
100 Variable names, preprocessor constants etc. shall be either based on
101 the string "u_boot" or on "U_BOOT". Example:
103 U_BOOT_VERSION u_boot_logo
104 IH_OS_U_BOOT u_boot_hush_start
110 U-Boot uses a 3 level version number containing a version, a
111 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112 sub-version "34", and patchlevel "4".
114 The patchlevel is used to indicate certain stages of development
115 between released versions, i. e. officially released versions of
116 U-Boot will always have a patchlevel of "0".
122 - board Board dependend files
123 - common Misc architecture independend functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Common used device drivers
128 - dtt Digital Thermometer and Thermostat drivers
129 - examples Example code for standalone applications, etc.
130 - include Header Files
131 - disk Harddisk interface code
132 - net Networking code
133 - ppc Files generic to PowerPC architecture
134 - post Power On Self Test
135 - post/arch Symlink to architecture specific Power On Self Test
136 - post/arch-ppc PowerPC architecture specific Power On Self Test
137 - post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138 - post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139 - rtc Real Time Clock drivers
140 - tools Tools to build S-Record or U-Boot images, etc.
142 - cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
143 - cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
144 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
145 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
146 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
147 - cpu/ppc4xx Files specific to IBM 4xx CPUs
149 - board/LEOX/ Files specific to boards manufactured by The LEOX team
150 - board/LEOX/elpt860 Files specific to ELPT860 boards
152 Files specific to RPXClassic boards
153 - board/RPXlite Files specific to RPXlite boards
154 - board/c2mon Files specific to c2mon boards
155 - board/cmi Files specific to cmi boards
156 - board/cogent Files specific to Cogent boards
157 (need further configuration)
158 Files specific to CPCIISER4 boards
159 - board/cpu86 Files specific to CPU86 boards
160 - board/cray/ Files specific to boards manufactured by Cray
161 - board/cray/L1 Files specific to L1 boards
162 - board/cu824 Files specific to CU824 boards
163 - board/ebony Files specific to IBM Ebony board
164 - board/eric Files specific to ERIC boards
165 - board/esd/ Files specific to boards manufactured by ESD
166 - board/esd/adciop Files specific to ADCIOP boards
167 - board/esd/ar405 Files specific to AR405 boards
168 - board/esd/canbt Files specific to CANBT boards
169 - board/esd/cpci405 Files specific to CPCI405 boards
170 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
171 - board/esd/common Common files for ESD boards
172 - board/esd/dasa_sim Files specific to DASA_SIM boards
173 - board/esd/du405 Files specific to DU405 boards
174 - board/esd/ocrtc Files specific to OCRTC boards
175 - board/esd/pci405 Files specific to PCI405 boards
177 Files specific to ESTEEM192E boards
178 - board/etx094 Files specific to ETX_094 boards
180 Files specific to EVB64260 boards
181 - board/fads Files specific to FADS boards
182 - board/flagadm Files specific to FLAGADM boards
183 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
184 - board/genietv Files specific to GENIETV boards
185 - board/gth Files specific to GTH boards
186 - board/hermes Files specific to HERMES boards
187 - board/hymod Files specific to HYMOD boards
188 - board/icu862 Files specific to ICU862 boards
189 - board/ip860 Files specific to IP860 boards
191 Files specific to Interphase4539 boards
192 - board/ivm Files specific to IVMS8/IVML24 boards
193 - board/lantec Files specific to LANTEC boards
194 - board/lwmon Files specific to LWMON boards
195 - board/mbx8xx Files specific to MBX boards
197 Files specific to MMPC8260ADS boards
198 - board/mpl/ Files specific to boards manufactured by MPL
199 - board/mpl/common Common files for MPL boards
200 - board/mpl/pip405 Files specific to PIP405 boards
201 - board/mpl/mip405 Files specific to MIP405 boards
202 - board/musenki Files specific to MUSEKNI boards
203 - board/mvs1 Files specific to MVS1 boards
204 - board/nx823 Files specific to NX823 boards
205 - board/oxc Files specific to OXC boards
206 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
207 - board/pm826 Files specific to PM826 boards
209 Files specific to PPMC8260 boards
211 Files specific to RPXsuper boards
213 Files specific to RSDproto boards
215 Files specific to Sandpoint boards
216 - board/sbc8260 Files specific to SBC8260 boards
217 - board/sacsng Files specific to SACSng boards
218 - board/siemens Files specific to boards manufactured by Siemens AG
219 - board/siemens/CCM Files specific to CCM boards
220 - board/siemens/IAD210 Files specific to IAD210 boards
221 - board/siemens/SCM Files specific to SCM boards
222 - board/siemens/pcu_e Files specific to PCU_E boards
223 - board/sixnet Files specific to SIXNET boards
224 - board/spd8xx Files specific to SPD8xxTS boards
225 - board/tqm8260 Files specific to TQM8260 boards
226 - board/tqm8xx Files specific to TQM8xxL boards
227 - board/w7o Files specific to W7O boards
229 Files specific to Walnut405 boards
230 - board/westel/ Files specific to boards manufactured by Westel Wireless
231 - board/westel/amx860 Files specific to AMX860 boards
232 - board/utx8245 Files specific to UTX8245 boards
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the cpu type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one of
296 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
298 or CONFIG_MPC824X, CONFIG_MPC8260
311 - Board Type: Define exactly one of
313 PowerPC based boards:
314 ---------------------
316 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
317 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
318 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
319 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
320 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
321 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
322 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
323 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
324 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
325 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
326 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
327 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
328 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
329 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
330 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
331 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
332 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
333 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
334 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
335 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
336 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
337 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
338 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
339 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
340 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
341 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
342 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
343 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
344 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
345 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
346 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
347 CONFIG_NETVIA, CONFIG_RBC823
352 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
353 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
354 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
358 - CPU Module Type: (if CONFIG_COGENT is defined)
359 Define exactly one of
361 --- FIXME --- not tested yet:
362 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
363 CONFIG_CMA287_23, CONFIG_CMA287_50
365 - Motherboard Type: (if CONFIG_COGENT is defined)
366 Define exactly one of
367 CONFIG_CMA101, CONFIG_CMA102
369 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
370 Define one or more of
373 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
374 Define one or more of
375 CONFIG_LCD_HEARTBEAT - update a character position on
376 the lcd display every second with
379 - MPC824X Family Member (if CONFIG_MPC824X is defined)
380 Define exactly one of
381 CONFIG_MPC8240, CONFIG_MPC8245
383 - 8xx CPU Options: (if using an 8xx cpu)
384 Define one or more of
385 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
386 no 32KHz reference PIT/RTC clock
391 U-Boot stores all clock information in Hz
392 internally. For binary compatibility with older Linux
393 kernels (which expect the clocks passed in the
394 bd_info data to be in MHz) the environment variable
395 "clocks_in_mhz" can be defined so that U-Boot
396 converts clock data to MHZ before passing it to the
399 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
400 "clocks_in_mhz=1" is automatically included in the
404 Depending on board, define exactly one serial port
405 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
406 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
407 console by defining CONFIG_8xx_CONS_NONE
409 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
410 port routines must be defined elsewhere
411 (i.e. serial_init(), serial_getc(), ...)
414 Enables console device for a color framebuffer. Needs following
415 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
416 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
418 VIDEO_HW_RECTFILL graphic chip supports
421 VIDEO_HW_BITBLT graphic chip supports
422 bit-blit (cf. smiLynxEM)
423 VIDEO_VISIBLE_COLS visible pixel columns
425 VIDEO_VISIBLE_ROWS visible pixel rows
426 VIDEO_PIXEL_SIZE bytes per pixel
427 VIDEO_DATA_FORMAT graphic data format
428 (0-5, cf. cfb_console.c)
429 VIDEO_FB_ADRS framebuffer address
430 VIDEO_KBD_INIT_FCT keyboard int fct
431 (i.e. i8042_kbd_init())
432 VIDEO_TSTC_FCT test char fct
434 VIDEO_GETC_FCT get char fct
436 CONFIG_CONSOLE_CURSOR cursor drawing on/off
437 (requires blink timer
439 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
440 CONFIG_CONSOLE_TIME display time/date info in
442 (requires CFG_CMD_DATE)
443 CONFIG_VIDEO_LOGO display Linux logo in
445 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
446 linux_logo.h for logo.
447 Requires CONFIG_VIDEO_LOGO
448 CONFIG_CONSOLE_EXTRA_INFO
449 addional board info beside
452 When CONFIG_CFB_CONSOLE is defined, video console is
453 default i/o. Serial console can be forced with
454 environment 'console=serial'.
457 CONFIG_BAUDRATE - in bps
458 Select one of the baudrates listed in
459 CFG_BAUDRATE_TABLE, see below.
461 - Interrupt driven serial port input:
462 CONFIG_SERIAL_SOFTWARE_FIFO
465 Use an interrupt handler for receiving data on the
466 serial port. It also enables using hardware handshake
467 (RTS/CTS) and UART's built-in FIFO. Set the number of
468 bytes the interrupt driven input buffer should have.
470 Set to 0 to disable this feature (this is the default).
471 This will also disable hardware handshake.
473 - Console UART Number:
477 If defined internal UART1 (and not UART0) is used
478 as default U-Boot console.
480 - Boot Delay: CONFIG_BOOTDELAY - in seconds
481 Delay before automatically booting the default image;
482 set to -1 to disable autoboot.
484 See doc/README.autoboot for these options that
485 work with CONFIG_BOOTDELAY. None are required.
486 CONFIG_BOOT_RETRY_TIME
487 CONFIG_BOOT_RETRY_MIN
488 CONFIG_AUTOBOOT_KEYED
489 CONFIG_AUTOBOOT_PROMPT
490 CONFIG_AUTOBOOT_DELAY_STR
491 CONFIG_AUTOBOOT_STOP_STR
492 CONFIG_AUTOBOOT_DELAY_STR2
493 CONFIG_AUTOBOOT_STOP_STR2
494 CONFIG_ZERO_BOOTDELAY_CHECK
495 CONFIG_RESET_TO_RETRY
499 Only needed when CONFIG_BOOTDELAY is enabled;
500 define a command string that is automatically executed
501 when no character is read on the console interface
502 within "Boot Delay" after reset.
505 This can be used to pass arguments to the bootm
506 command. The value of CONFIG_BOOTARGS goes into the
507 environment value "bootargs".
509 CONFIG_RAMBOOT and CONFIG_NFSBOOT
510 The value of these goes into the environment as
511 "ramboot" and "nfsboot" respectively, and can be used
512 as a convenience, when switching between booting from
518 When this option is #defined, the existence of the
519 environment variable "preboot" will be checked
520 immediately before starting the CONFIG_BOOTDELAY
521 countdown and/or running the auto-boot command resp.
522 entering interactive mode.
524 This feature is especially useful when "preboot" is
525 automatically generated or modified. For an example
526 see the LWMON board specific code: here "preboot" is
527 modified when the user holds down a certain
528 combination of keys on the (special) keyboard when
531 - Serial Download Echo Mode:
533 If defined to 1, all characters received during a
534 serial download (using the "loads" command) are
535 echoed back. This might be needed by some terminal
536 emulations (like "cu"), but may as well just take
537 time on others. This setting #define's the initial
538 value of the "loads_echo" environment variable.
540 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
542 Select one of the baudrates listed in
543 CFG_BAUDRATE_TABLE, see below.
547 Most monitor functions can be selected (or
548 de-selected) by adjusting the definition of
549 CONFIG_COMMANDS; to select individual functions,
550 #define CONFIG_COMMANDS by "OR"ing any of the
553 #define enables commands:
554 -------------------------
555 CFG_CMD_ASKENV * ask for env variable
557 CFG_CMD_BEDBUG Include BedBug Debugger
559 CFG_CMD_CACHE icache, dcache
560 CFG_CMD_CONSOLE coninfo
561 CFG_CMD_DATE * support for RTC, date/time...
562 CFG_CMD_DHCP DHCP support
563 CFG_CMD_ECHO * echo arguments
564 CFG_CMD_EEPROM * EEPROM read/write support
565 CFG_CMD_ELF bootelf, bootvx
567 CFG_CMD_FDC * Floppy Disk Support
568 CFG_CMD_FDOS * Dos diskette Support
569 CFG_CMD_FLASH flinfo, erase, protect
570 CFG_CMD_FPGA FPGA device initialization support
571 CFG_CMD_I2C * I2C serial bus support
572 CFG_CMD_IDE * IDE harddisk support
574 CFG_CMD_IMMAP * IMMR dump support
575 CFG_CMD_IRQ * irqinfo
579 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
581 CFG_CMD_MII MII utility commands
582 CFG_CMD_NET bootp, tftpboot, rarpboot
583 CFG_CMD_PCI * pciinfo
584 CFG_CMD_PCMCIA * PCMCIA support
585 CFG_CMD_REGINFO * Register dump
586 CFG_CMD_RUN run command in env variable
587 CFG_CMD_SCSI * SCSI Support
588 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
589 CFG_CMD_SPI * SPI serial bus support
590 CFG_CMD_USB * USB support
591 CFG_CMD_BSP * Board SPecific functions
592 -----------------------------------------------
595 CFG_CMD_DFL Default configuration; at the moment
596 this is includes all commands, except
597 the ones marked with "*" in the list
600 If you don't define CONFIG_COMMANDS it defaults to
601 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
602 override the default settings in the respective
605 EXAMPLE: If you want all functions except of network
606 support you can write:
608 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
611 Note: Don't enable the "icache" and "dcache" commands
612 (configuration option CFG_CMD_CACHE) unless you know
613 what you (and your U-Boot users) are doing. Data
614 cache cannot be enabled on systems like the 8xx or
615 8260 (where accesses to the IMMR region must be
616 uncached), and it cannot be disabled on all other
617 systems where we (mis-) use the data cache to hold an
618 initial stack and some data.
621 XXX - this list needs to get updated!
625 If this variable is defined, it enables watchdog
626 support. There must support in the platform specific
627 code for a watchdog. For the 8xx and 8260 CPUs, the
628 SIU Watchdog feature is enabled in the SYPCR
632 CONFIG_VERSION_VARIABLE
633 If this variable is defined, an environment variable
634 named "ver" is created by U-Boot showing the U-Boot
635 version as printed by the "version" command.
636 This variable is readonly.
640 When CFG_CMD_DATE is selected, the type of the RTC
641 has to be selected, too. Define exactly one of the
644 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
645 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
646 CONFIG_RTC_MC146818 - use MC146818 RTC
647 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
648 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
649 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
650 CONFIG_RTC_DS164x - use Dallas DS164x RTC
654 When CONFIG_TIMESTAMP is selected, the timestamp
655 (date and time) of an image is printed by image
656 commands like bootm or iminfo. This option is
657 automatically enabled when you select CFG_CMD_DATE .
660 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
661 and/or CONFIG_ISO_PARTITION
663 If IDE or SCSI support is enabled (CFG_CMD_IDE or
664 CFG_CMD_SCSI) you must configure support for at least
665 one partition type as well.
668 CONFIG_IDE_RESET_ROUTINE
670 Set this to define that instead of a reset Pin, the
671 routine ide_set_reset(int idereset) will be used.
676 Set this to enable ATAPI support.
679 At the moment only there is only support for the
680 SYM53C8XX SCSI controller; define
681 CONFIG_SCSI_SYM53C8XX to enable it.
683 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
684 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
685 CFG_SCSI_MAX_LUN] can be adjusted to define the
686 maximum numbers of LUNs, SCSI ID's and target
688 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
690 - NETWORK Support (PCI):
692 Support for Intel 8254x gigabit chips.
695 Support for Intel 82557/82559/82559ER chips.
696 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
697 write routine for first time initialisation.
700 Support for Digital 2114x chips.
701 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
702 modem chip initialisation (KS8761/QS6611).
705 Support for National dp83815 chips.
708 Support for National dp8382[01] gigabit chips.
710 - NETWORK Support (other):
712 CONFIG_DRIVER_LAN91C96
713 Support for SMSC's LAN91C96 chips.
716 Define this to hold the physical address
717 of the LAN91C96's I/O space
719 CONFIG_LAN91C96_USE_32_BIT
720 Define this to enable 32 bit addressing
723 At the moment only the UHCI host controller is
724 supported (PIP405, MIP405); define
725 CONFIG_USB_UHCI to enable it.
726 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
727 end define CONFIG_USB_STORAGE to enable the USB
730 Supported are USB Keyboards and USB Floppy drives
736 Define this to enable standard (PC-Style) keyboard
740 Standard PC keyboard driver with US (is default) and
741 GERMAN key layout (switch via environment 'keymap=de') support.
742 Export function i8042_kbd_init, i8042_tstc and i8042_getc
743 for cfb_console. Supports cursor blinking.
748 Define this to enable video support (for output to
753 Enable Chips & Technologies 69000 Video chip
755 CONFIG_VIDEO_SMI_LYNXEM
756 Enable Silicon Motion SMI 712/710/810 Video chip
757 Videomode are selected via environment 'videomode' with
758 standard LiLo mode numbers.
759 Following modes are supported (* is default):
761 800x600 1024x768 1280x1024
762 256 (8bit) 303* 305 307
763 65536 (16bit) 314 317 31a
764 16,7 Mill (24bit) 315 318 31b
765 (i.e. setenv videomode 317; saveenv; reset;)
767 CONFIG_VIDEO_SED13806
768 Enable Epson SED13806 driver. This driver supports 8bpp
769 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
770 or CONFIG_VIDEO_SED13806_16BPP
775 Define this to enable a custom keyboard support.
776 This simply calls drv_keyboard_init() which must be
777 defined in your board-specific files.
778 The only board using this so far is RBC823.
780 - LCD Support: CONFIG_LCD
782 Define this to enable LCD support (for output to LCD
783 display); also select one of the supported displays
784 by defining one of these:
786 CONFIG_NEC_NL6648AC33:
788 NEC NL6648AC33-18. Active, color, single scan.
790 CONFIG_NEC_NL6648BC20
792 NEC NL6648BC20-08. 6.5", 640x480.
793 Active, color, single scan.
797 Sharp 320x240. Active, color, single scan.
798 It isn't 16x9, and I am not sure what it is.
800 CONFIG_SHARP_LQ64D341
802 Sharp LQ64D341 display, 640x480.
803 Active, color, single scan.
807 HLD1045 display, 640x480.
808 Active, color, single scan.
812 Optrex CBL50840-2 NF-FW 99 22 M5
814 Hitachi LMG6912RPFC-00T
818 320x240. Black & white.
820 Normally display is black on white background; define
821 CFG_WHITE_ON_BLACK to get it inverted.
823 - Spash Screen Support: CONFIG_SPLASH_SCREEN
825 If this option is set, the environment is checked for
826 a variable "splashimage". If found, the usual display
827 of logo, copyright and system information on the LCD
828 is supressed and the BMP image at the address
829 specified in "splashimage" is loaded instead. The
830 console is redirected to the "nulldev", too. This
831 allows for a "silent" boot where a splash screen is
832 loaded very quickly after power-on.
840 Define a default value for ethernet address to use
841 for the respective ethernet interface, in case this
842 is not determined automatically.
847 Define a default value for the IP address to use for
848 the default ethernet interface, in case this is not
849 determined through e.g. bootp.
854 Defines a default value for theIP address of a TFTP
855 server to contact when using the "tftboot" command.
857 - BOOTP Recovery Mode:
858 CONFIG_BOOTP_RANDOM_DELAY
860 If you have many targets in a network that try to
861 boot using BOOTP, you may want to avoid that all
862 systems send out BOOTP requests at precisely the same
863 moment (which would happen for instance at recovery
864 from a power failure, when all systems will try to
865 boot, thus flooding the BOOTP server. Defining
866 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
867 inserted before sending out BOOTP requests. The
868 following delays are insterted then:
870 1st BOOTP request: delay 0 ... 1 sec
871 2nd BOOTP request: delay 0 ... 2 sec
872 3rd BOOTP request: delay 0 ... 4 sec
874 BOOTP requests: delay 0 ... 8 sec
876 - Status LED: CONFIG_STATUS_LED
878 Several configurations allow to display the current
879 status using a LED. For instance, the LED will blink
880 fast while running U-Boot code, stop blinking as
881 soon as a reply to a BOOTP request was received, and
882 start blinking slow once the Linux kernel is running
883 (supported by a status LED driver in the Linux
884 kernel). Defining CONFIG_STATUS_LED enables this
887 - CAN Support: CONFIG_CAN_DRIVER
889 Defining CONFIG_CAN_DRIVER enables CAN driver support
890 on those systems that support this (optional)
891 feature, like the TQM8xxL modules.
893 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
895 Enables I2C serial bus commands. If this is selected,
896 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
897 to include the appropriate I2C driver.
899 See also: common/cmd_i2c.c for a description of the
900 command line interface.
905 Selects the CPM hardware driver for I2C.
909 Use software (aka bit-banging) driver instead of CPM
910 or similar hardware support for I2C. This is configured
911 via the following defines.
915 (Optional). Any commands necessary to enable I2C
916 controller or configure ports.
920 (Only for MPC8260 CPU). The I/O port to use (the code
921 assumes both bits are on the same port). Valid values
922 are 0..3 for ports A..D.
926 The code necessary to make the I2C data line active
927 (driven). If the data line is open collector, this
932 The code necessary to make the I2C data line tri-stated
933 (inactive). If the data line is open collector, this
938 Code that returns TRUE if the I2C data line is high,
943 If <bit> is TRUE, sets the I2C data line high. If it
944 is FALSE, it clears it (low).
948 If <bit> is TRUE, sets the I2C clock line high. If it
949 is FALSE, it clears it (low).
953 This delay is invoked four times per clock cycle so this
954 controls the rate of data transfer. The data rate thus
955 is 1 / (I2C_DELAY * 4).
959 When a board is reset during an i2c bus transfer
960 chips might think that the current transfer is still
961 in progress. On some boards it is possible to access
962 the i2c SCLK line directly, either by using the
963 processor pin as a GPIO or by having a second pin
964 connected to the bus. If this option is defined a
965 custom i2c_init_board() routine in boards/xxx/board.c
966 is run early in the boot sequence.
968 - SPI Support: CONFIG_SPI
970 Enables SPI driver (so far only tested with
971 SPI EEPROM, also an instance works with Crystal A/D and
972 D/As on the SACSng board)
976 Enables extended (16-bit) SPI EEPROM addressing.
977 (symmetrical to CONFIG_I2C_X)
981 Enables a software (bit-bang) SPI driver rather than
982 using hardware support. This is a general purpose
983 driver that only requires three general I/O port pins
984 (two outputs, one input) to function. If this is
985 defined, the board configuration must define several
986 SPI configuration items (port pins to use, etc). For
987 an example, see include/configs/sacsng.h.
989 - FPGA Support: CONFIG_FPGA_COUNT
991 Specify the number of FPGA devices to support.
995 Used to specify the types of FPGA devices. For
997 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
999 CFG_FPGA_PROG_FEEDBACK
1001 Enable printing of hash marks during FPGA
1006 Enable checks on FPGA configuration interface busy
1007 status by the configuration function. This option
1008 will require a board or device specific function to
1013 If defined, a function that provides delays in the
1014 FPGA configuration driver.
1016 CFG_FPGA_CHECK_CTRLC
1018 Allow Control-C to interrupt FPGA configuration
1020 CFG_FPGA_CHECK_ERROR
1022 Check for configuration errors during FPGA bitfile
1023 loading. For example, abort during Virtex II
1024 configuration if the INIT_B line goes low (which
1025 indicated a CRC error).
1029 Maximum time to wait for the INIT_B line to deassert
1030 after PROB_B has been deasserted during a Virtex II
1031 FPGA configuration sequence. The default time is 500 mS.
1035 Maximum time to wait for BUSY to deassert during
1036 Virtex II FPGA configuration. The default is 5 mS.
1038 CFG_FPGA_WAIT_CONFIG
1040 Time to wait after FPGA configuration. The default is
1043 - FPGA Support: CONFIG_FPGA_COUNT
1045 Specify the number of FPGA devices to support.
1049 Used to specify the types of FPGA devices. For example,
1050 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1052 CFG_FPGA_PROG_FEEDBACK
1054 Enable printing of hash marks during FPGA configuration.
1058 Enable checks on FPGA configuration interface busy
1059 status by the configuration function. This option
1060 will require a board or device specific function to
1065 If defined, a function that provides delays in the FPGA
1066 configuration driver.
1068 CFG_FPGA_CHECK_CTRLC
1069 Allow Control-C to interrupt FPGA configuration
1071 CFG_FPGA_CHECK_ERROR
1073 Check for configuration errors during FPGA bitfile
1074 loading. For example, abort during Virtex II
1075 configuration if the INIT_B line goes low (which
1076 indicated a CRC error).
1080 Maximum time to wait for the INIT_B line to deassert
1081 after PROB_B has been deasserted during a Virtex II
1082 FPGA configuration sequence. The default time is 500
1087 Maximum time to wait for BUSY to deassert during
1088 Virtex II FPGA configuration. The default is 5 mS.
1090 CFG_FPGA_WAIT_CONFIG
1092 Time to wait after FPGA configuration. The default is
1095 - Configuration Management:
1098 If defined, this string will be added to the U-Boot
1099 version information (U_BOOT_VERSION)
1101 - Vendor Parameter Protection:
1103 U-Boot considers the values of the environment
1104 variables "serial#" (Board Serial Number) and
1105 "ethaddr" (Ethernet Address) to bb parameters that
1106 are set once by the board vendor / manufacturer, and
1107 protects these variables from casual modification by
1108 the user. Once set, these variables are read-only,
1109 and write or delete attempts are rejected. You can
1110 change this behviour:
1112 If CONFIG_ENV_OVERWRITE is #defined in your config
1113 file, the write protection for vendor parameters is
1114 completely disabled. Anybody can change or delete
1117 Alternatively, if you #define _both_ CONFIG_ETHADDR
1118 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1119 ethernet address is installed in the environment,
1120 which can be changed exactly ONCE by the user. [The
1121 serial# is unaffected by this, i. e. it remains
1127 Define this variable to enable the reservation of
1128 "protected RAM", i. e. RAM which is not overwritten
1129 by U-Boot. Define CONFIG_PRAM to hold the number of
1130 kB you want to reserve for pRAM. You can overwrite
1131 this default value by defining an environment
1132 variable "pram" to the number of kB you want to
1133 reserve. Note that the board info structure will
1134 still show the full amount of RAM. If pRAM is
1135 reserved, a new environment variable "mem" will
1136 automatically be defined to hold the amount of
1137 remaining RAM in a form that can be passed as boot
1138 argument to Linux, for instance like that:
1140 setenv bootargs ... mem=\$(mem)
1143 This way you can tell Linux not to use this memory,
1144 either, which results in a memory region that will
1145 not be affected by reboots.
1147 *WARNING* If your board configuration uses automatic
1148 detection of the RAM size, you must make sure that
1149 this memory test is non-destructive. So far, the
1150 following board configurations are known to be
1153 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1154 HERMES, IP860, RPXlite, LWMON, LANTEC,
1155 PCU_E, FLAGADM, TQM8260
1160 Define this variable to stop the system in case of a
1161 fatal error, so that you have to reset it manually.
1162 This is probably NOT a good idea for an embedded
1163 system where you want to system to reboot
1164 automatically as fast as possible, but it may be
1165 useful during development since you can try to debug
1166 the conditions that lead to the situation.
1168 CONFIG_NET_RETRY_COUNT
1170 This variable defines the number of retries for
1171 network operations like ARP, RARP, TFTP, or BOOTP
1172 before giving up the operation. If not defined, a
1173 default value of 5 is used.
1175 - Command Interpreter:
1178 Define this variable to enable the "hush" shell (from
1179 Busybox) as command line interpreter, thus enabling
1180 powerful command line syntax like
1181 if...then...else...fi conditionals or `&&' and '||'
1182 constructs ("shell scripts").
1184 If undefined, you get the old, much simpler behaviour
1185 with a somewhat smaller memory footprint.
1190 This defines the secondary prompt string, which is
1191 printed when the command interpreter needs more input
1192 to complete a command. Usually "> ".
1196 In the current implementation, the local variables
1197 space and global environment variables space are
1198 separated. Local variables are those you define by
1199 simply typing `name=value'. To access a local
1200 variable later on, you have write `$name' or
1201 `${name}'; to execute the contents of a variable
1202 directly type `$name' at the command prompt.
1204 Global environment variables are those you use
1205 setenv/printenv to work with. To run a command stored
1206 in such a variable, you need to use the run command,
1207 and you must not use the '$' sign to access them.
1209 To store commands and special characters in a
1210 variable, please use double quotation marks
1211 surrounding the whole text of the variable, instead
1212 of the backslashes before semicolons and special
1215 - Default Environment
1216 CONFIG_EXTRA_ENV_SETTINGS
1218 Define this to contain any number of null terminated
1219 strings (variable = value pairs) that will be part of
1220 the default enviroment compiled into the boot image.
1222 For example, place something like this in your
1223 board's config file:
1225 #define CONFIG_EXTRA_ENV_SETTINGS \
1229 Warning: This method is based on knowledge about the
1230 internal format how the environment is stored by the
1231 U-Boot code. This is NOT an official, exported
1232 interface! Although it is unlikely that this format
1233 will change soon, but there is no guarantee either.
1234 You better know what you are doing here.
1236 Note: overly (ab)use of the default environment is
1237 discouraged. Make sure to check other ways to preset
1238 the environment like the autoscript function or the
1241 - Show boot progress
1242 CONFIG_SHOW_BOOT_PROGRESS
1244 Defining this option allows to add some board-
1245 specific code (calling a user-provided function
1246 "show_boot_progress(int)") that enables you to show
1247 the system's boot progress on some display (for
1248 example, some LED's) on your board. At the moment,
1249 the following checkpoints are implemented:
1252 1 common/cmd_bootm.c before attempting to boot an image
1253 -1 common/cmd_bootm.c Image header has bad magic number
1254 2 common/cmd_bootm.c Image header has correct magic number
1255 -2 common/cmd_bootm.c Image header has bad checksum
1256 3 common/cmd_bootm.c Image header has correct checksum
1257 -3 common/cmd_bootm.c Image data has bad checksum
1258 4 common/cmd_bootm.c Image data has correct checksum
1259 -4 common/cmd_bootm.c Image is for unsupported architecture
1260 5 common/cmd_bootm.c Architecture check OK
1261 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1262 6 common/cmd_bootm.c Image Type check OK
1263 -6 common/cmd_bootm.c gunzip uncompression error
1264 -7 common/cmd_bootm.c Unimplemented compression type
1265 7 common/cmd_bootm.c Uncompression OK
1266 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1267 8 common/cmd_bootm.c Image Type check OK
1268 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1269 9 common/cmd_bootm.c Start initial ramdisk verification
1270 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1271 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1272 10 common/cmd_bootm.c Ramdisk header is OK
1273 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1274 11 common/cmd_bootm.c Ramdisk data has correct checksum
1275 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1276 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1277 13 common/cmd_bootm.c Start multifile image verification
1278 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1279 15 common/cmd_bootm.c All preparation done, transferring control to OS
1281 -1 common/cmd_doc.c Bad usage of "doc" command
1282 -1 common/cmd_doc.c No boot device
1283 -1 common/cmd_doc.c Unknown Chip ID on boot device
1284 -1 common/cmd_doc.c Read Error on boot device
1285 -1 common/cmd_doc.c Image header has bad magic number
1287 -1 common/cmd_ide.c Bad usage of "ide" command
1288 -1 common/cmd_ide.c No boot device
1289 -1 common/cmd_ide.c Unknown boot device
1290 -1 common/cmd_ide.c Unknown partition table
1291 -1 common/cmd_ide.c Invalid partition type
1292 -1 common/cmd_ide.c Read Error on boot device
1293 -1 common/cmd_ide.c Image header has bad magic number
1295 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1301 [so far only for SMDK2400 and TRAB boards]
1303 - Modem support endable:
1304 CONFIG_MODEM_SUPPORT
1306 - RTS/CTS Flow control enable:
1309 - Modem debug support:
1310 CONFIG_MODEM_SUPPORT_DEBUG
1312 Enables debugging stuff (char screen[1024], dbg())
1313 for modem support. Useful only with BDI2000.
1317 In the target system modem support is enabled when a
1318 specific key (key combination) is pressed during
1319 power-on. Otherwise U-Boot will boot normally
1320 (autoboot). The key_pressed() fuction is called from
1321 board_init(). Currently key_pressed() is a dummy
1322 function, returning 1 and thus enabling modem
1325 If there are no modem init strings in the
1326 environment, U-Boot proceed to autoboot; the
1327 previous output (banner, info printfs) will be
1330 See also: doc/README.Modem
1335 Configuration Settings:
1336 -----------------------
1338 - CFG_LONGHELP: Defined when you want long help messages included;
1339 undefine this when you're short of memory.
1341 - CFG_PROMPT: This is what U-Boot prints on the console to
1342 prompt for user input.
1344 - CFG_CBSIZE: Buffer size for input from the Console
1346 - CFG_PBSIZE: Buffer size for Console output
1348 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1350 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1351 the application (usually a Linux kernel) when it is
1354 - CFG_BAUDRATE_TABLE:
1355 List of legal baudrate settings for this board.
1357 - CFG_CONSOLE_INFO_QUIET
1358 Suppress display of console information at boot.
1360 - CFG_CONSOLE_IS_IN_ENV
1361 If the board specific function
1362 extern int overwrite_console (void);
1363 returns 1, the stdin, stderr and stdout are switched to the
1364 serial port, else the settings in the environment are used.
1366 - CFG_CONSOLE_OVERWRITE_ROUTINE
1367 Enable the call to overwrite_console().
1369 - CFG_CONSOLE_ENV_OVERWRITE
1370 Enable overwrite of previous console environment settings.
1372 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1373 Begin and End addresses of the area used by the
1377 Enable an alternate, more extensive memory test.
1379 - CFG_TFTP_LOADADDR:
1380 Default load address for network file downloads
1382 - CFG_LOADS_BAUD_CHANGE:
1383 Enable temporary baudrate change while serial download
1386 Physical start address of SDRAM. _Must_ be 0 here.
1389 Physical start address of Motherboard I/O (if using a
1393 Physical start address of Flash memory.
1396 Physical start address of boot monitor code (set by
1397 make config files to be same as the text base address
1398 (TEXT_BASE) used when linking) - same as
1399 CFG_FLASH_BASE when booting from flash.
1402 Size of memory reserved for monitor code, used to
1403 determine _at_compile_time_ (!) if the environment is
1404 embedded within the U-Boot image, or in a separate
1408 Size of DRAM reserved for malloc() use.
1411 Maximum size of memory mapped by the startup code of
1412 the Linux kernel; all data that must be processed by
1413 the Linux kernel (bd_info, boot arguments, eventually
1414 initrd image) must be put below this limit.
1416 - CFG_MAX_FLASH_BANKS:
1417 Max number of Flash memory banks
1419 - CFG_MAX_FLASH_SECT:
1420 Max number of sectors on a Flash chip
1422 - CFG_FLASH_ERASE_TOUT:
1423 Timeout for Flash erase operations (in ms)
1425 - CFG_FLASH_WRITE_TOUT:
1426 Timeout for Flash write operations (in ms)
1428 - CFG_DIRECT_FLASH_TFTP:
1430 Enable TFTP transfers directly to flash memory;
1431 without this option such a download has to be
1432 performed in two steps: (1) download to RAM, and (2)
1433 copy from RAM to flash.
1435 The two-step approach is usually more reliable, since
1436 you can check if the download worked before you erase
1437 the flash, but in some situations (when sytem RAM is
1438 too limited to allow for a tempory copy of the
1439 downloaded image) this option may be very useful.
1442 Define if the flash driver uses extra elements in the
1443 common flash structure for storing flash geometry
1445 - CFG_RX_ETH_BUFFER:
1446 Defines the number of ethernet receive buffers. On some
1447 ethernet controllers it is recommended to set this value
1448 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1449 buffers can be full shortly after enabling the interface
1450 on high ethernet traffic.
1451 Defaults to 4 if not defined.
1453 The following definitions that deal with the placement and management
1454 of environment data (variable area); in general, we support the
1455 following configurations:
1457 - CFG_ENV_IS_IN_FLASH:
1459 Define this if the environment is in flash memory.
1461 a) The environment occupies one whole flash sector, which is
1462 "embedded" in the text segment with the U-Boot code. This
1463 happens usually with "bottom boot sector" or "top boot
1464 sector" type flash chips, which have several smaller
1465 sectors at the start or the end. For instance, such a
1466 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1467 such a case you would place the environment in one of the
1468 4 kB sectors - with U-Boot code before and after it. With
1469 "top boot sector" type flash chips, you would put the
1470 environment in one of the last sectors, leaving a gap
1471 between U-Boot and the environment.
1475 Offset of environment data (variable area) to the
1476 beginning of flash memory; for instance, with bottom boot
1477 type flash chips the second sector can be used: the offset
1478 for this sector is given here.
1480 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1484 This is just another way to specify the start address of
1485 the flash sector containing the environment (instead of
1488 - CFG_ENV_SECT_SIZE:
1490 Size of the sector containing the environment.
1493 b) Sometimes flash chips have few, equal sized, BIG sectors.
1494 In such a case you don't want to spend a whole sector for
1499 If you use this in combination with CFG_ENV_IS_IN_FLASH
1500 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1501 of this flash sector for the environment. This saves
1502 memory for the RAM copy of the environment.
1504 It may also save flash memory if you decide to use this
1505 when your environment is "embedded" within U-Boot code,
1506 since then the remainder of the flash sector could be used
1507 for U-Boot code. It should be pointed out that this is
1508 STRONGLY DISCOURAGED from a robustness point of view:
1509 updating the environment in flash makes it always
1510 necessary to erase the WHOLE sector. If something goes
1511 wrong before the contents has been restored from a copy in
1512 RAM, your target system will be dead.
1514 - CFG_ENV_ADDR_REDUND
1517 These settings describe a second storage area used to hold
1518 a redundand copy of the environment data, so that there is
1519 a valid backup copy in case there is a power failure during
1520 a "saveenv" operation.
1522 BE CAREFUL! Any changes to the flash layout, and some changes to the
1523 source code will make it necessary to adapt <board>/u-boot.lds*
1527 - CFG_ENV_IS_IN_NVRAM:
1529 Define this if you have some non-volatile memory device
1530 (NVRAM, battery buffered SRAM) which you want to use for the
1536 These two #defines are used to determin the memory area you
1537 want to use for environment. It is assumed that this memory
1538 can just be read and written to, without any special
1541 BE CAREFUL! The first access to the environment happens quite early
1542 in U-Boot initalization (when we try to get the setting of for the
1543 console baudrate). You *MUST* have mappend your NVRAM area then, or
1546 Please note that even with NVRAM we still use a copy of the
1547 environment in RAM: we could work on NVRAM directly, but we want to
1548 keep settings there always unmodified except somebody uses "saveenv"
1549 to save the current settings.
1552 - CFG_ENV_IS_IN_EEPROM:
1554 Use this if you have an EEPROM or similar serial access
1555 device and a driver for it.
1560 These two #defines specify the offset and size of the
1561 environment area within the total memory of your EEPROM.
1563 - CFG_I2C_EEPROM_ADDR:
1564 If defined, specified the chip address of the EEPROM device.
1565 The default address is zero.
1567 - CFG_EEPROM_PAGE_WRITE_BITS:
1568 If defined, the number of bits used to address bytes in a
1569 single page in the EEPROM device. A 64 byte page, for example
1570 would require six bits.
1572 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1573 If defined, the number of milliseconds to delay between
1574 page writes. The default is zero milliseconds.
1576 - CFG_I2C_EEPROM_ADDR_LEN:
1577 The length in bytes of the EEPROM memory array address. Note
1578 that this is NOT the chip address length!
1581 The size in bytes of the EEPROM device.
1584 - CFG_SPI_INIT_OFFSET
1586 Defines offset to the initial SPI buffer area in DPRAM. The
1587 area is used at an early stage (ROM part) if the environment
1588 is configured to reside in the SPI EEPROM: We need a 520 byte
1589 scratch DPRAM area. It is used between the two initialization
1590 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1591 to be a good choice since it makes it far enough from the
1592 start of the data area as well as from the stack pointer.
1594 Please note that the environment is read-only as long as the monitor
1595 has been relocated to RAM and a RAM copy of the environment has been
1596 created; also, when using EEPROM you will have to use getenv_r()
1597 until then to read environment variables.
1599 The environment is protected by a CRC32 checksum. Before the monitor
1600 is relocated into RAM, as a result of a bad CRC you will be working
1601 with the compiled-in default environment - *silently*!!! [This is
1602 necessary, because the first environment variable we need is the
1603 "baudrate" setting for the console - if we have a bad CRC, we don't
1604 have any device yet where we could complain.]
1606 Note: once the monitor has been relocated, then it will complain if
1607 the default environment is used; a new CRC is computed as soon as you
1608 use the "saveenv" command to store a valid environment.
1611 Low Level (hardware related) configuration options:
1612 ---------------------------------------------------
1614 - CFG_CACHELINE_SIZE:
1615 Cache Line Size of the CPU.
1618 Default address of the IMMR after system reset.
1619 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1620 to be able to adjust the position of the IMMR
1621 register after a reset.
1623 - Floppy Disk Support:
1624 CFG_FDC_DRIVE_NUMBER
1626 the default drive number (default value 0)
1630 defines the spacing between fdc chipset registers
1635 defines the offset of register from address. It
1636 depends on which part of the data bus is connected to
1637 the fdc chipset. (default value 0)
1639 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1640 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1643 if CFG_FDC_HW_INIT is defined, then the function
1644 fdc_hw_init() is called at the beginning of the FDC
1645 setup. fdc_hw_init() must be provided by the board
1646 source code. It is used to make hardware dependant
1649 - CFG_IMMR: Physical address of the Internal Memory Mapped
1650 Register; DO NOT CHANGE! (11-4)
1651 [MPC8xx systems only]
1653 - CFG_INIT_RAM_ADDR:
1655 Start address of memory area tha can be used for
1656 initial data and stack; please note that this must be
1657 writable memory that is working WITHOUT special
1658 initialization, i. e. you CANNOT use normal RAM which
1659 will become available only after programming the
1660 memory controller and running certain initialization
1663 U-Boot uses the following memory types:
1664 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1665 - MPC824X: data cache
1666 - PPC4xx: data cache
1668 - CFG_GBL_DATA_OFFSET:
1670 Offset of the initial data structure in the memory
1671 area defined by CFG_INIT_RAM_ADDR. Usually
1672 CFG_GBL_DATA_OFFSET is chosen such that the initial
1673 data is located at the end of the available space
1674 (sometimes written as (CFG_INIT_RAM_END -
1675 CFG_INIT_DATA_SIZE), and the initial stack is just
1676 below that area (growing from (CFG_INIT_RAM_ADDR +
1677 CFG_GBL_DATA_OFFSET) downward.
1680 On the MPC824X (or other systems that use the data
1681 cache for initial memory) the address chosen for
1682 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1683 point to an otherwise UNUSED address space between
1684 the top of RAM and the start of the PCI space.
1686 - CFG_SIUMCR: SIU Module Configuration (11-6)
1688 - CFG_SYPCR: System Protection Control (11-9)
1690 - CFG_TBSCR: Time Base Status and Control (11-26)
1692 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1694 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1696 - CFG_SCCR: System Clock and reset Control Register (15-27)
1698 - CFG_OR_TIMING_SDRAM:
1702 periodic timer for refresh
1704 - CFG_DER: Debug Event Register (37-47)
1706 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1707 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1708 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1710 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1712 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1713 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1714 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1715 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1717 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1718 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1719 Machine Mode Register and Memory Periodic Timer
1720 Prescaler definitions (SDRAM timing)
1722 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1723 enable I2C microcode relocation patch (MPC8xx);
1724 define relocation offset in DPRAM [DSP2]
1726 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1727 enable SPI microcode relocation patch (MPC8xx);
1728 define relocation offset in DPRAM [SCC4]
1731 Use OSCM clock mode on MBX8xx board. Be careful,
1732 wrong setting might damage your board. Read
1733 doc/README.MBX before setting this variable!
1735 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1736 Offset of the bootmode word in DPRAM used by post
1737 (Power On Self Tests). This definition overrides
1738 #define'd default value in commproc.h resp.
1741 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1742 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1743 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1744 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1745 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1746 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1747 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1748 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1749 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1751 Building the Software:
1752 ======================
1754 Building U-Boot has been tested in native PPC environments (on a
1755 PowerBook G3 running LinuxPPC 2000) and in cross environments
1756 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1759 If you are not using a native PPC environment, it is assumed that you
1760 have the GNU cross compiling tools available in your path and named
1761 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1762 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1763 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1766 CROSS_COMPILE = ppc_4xx-
1769 U-Boot is intended to be simple to build. After installing the
1770 sources you must configure U-Boot for one specific board type. This
1775 where "NAME_config" is the name of one of the existing
1776 configurations; the following names are supported:
1778 ADCIOP_config GTH_config TQM850L_config
1779 ADS860_config IP860_config TQM855L_config
1780 AR405_config IVML24_config TQM860L_config
1781 CANBT_config IVMS8_config WALNUT405_config
1782 CPCI405_config LANTEC_config cogent_common_config
1783 CPCIISER4_config MBX_config cogent_mpc8260_config
1784 CU824_config MBX860T_config cogent_mpc8xx_config
1785 ESTEEM192E_config RPXlite_config hermes_config
1786 ETX094_config RPXsuper_config hymod_config
1787 FADS823_config SM850_config lwmon_config
1788 FADS850SAR_config SPD823TS_config pcu_e_config
1789 FADS860T_config SXNI855T_config rsdproto_config
1790 FPS850L_config Sandpoint8240_config sbc8260_config
1791 GENIETV_config TQM823L_config PIP405_config
1792 GEN860T_config EBONY_config FPS860L_config
1793 ELPT860_config cmi_mpc5xx_config NETVIA_config
1795 Note: for some board special configuration names may exist; check if
1796 additional information is available from the board vendor; for
1797 instance, the TQM8xxL systems run normally at 50 MHz and use a
1798 SCC for 10baseT ethernet; there are also systems with 80 MHz
1799 CPU clock, and an optional Fast Ethernet module is available
1800 for CPU's with FEC. You can select such additional "features"
1801 when chosing the configuration, i. e.
1804 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1806 make TQM860L_FEC_config
1807 - will configure for a TQM860L at 50MHz with FEC for ethernet
1809 make TQM860L_80MHz_config
1810 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1813 make TQM860L_FEC_80MHz_config
1814 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1816 make TQM823L_LCD_config
1817 - will configure for a TQM823L with U-Boot console on LCD
1819 make TQM823L_LCD_80MHz_config
1820 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1826 Finally, type "make all", and you should get some working U-Boot
1827 images ready for downlod to / installation on your system:
1829 - "u-boot.bin" is a raw binary image
1830 - "u-boot" is an image in ELF binary format
1831 - "u-boot.srec" is in Motorola S-Record format
1834 Please be aware that the Makefiles assume you are using GNU make, so
1835 for instance on NetBSD you might need to use "gmake" instead of
1839 If the system board that you have is not listed, then you will need
1840 to port U-Boot to your hardware platform. To do this, follow these
1843 1. Add a new configuration option for your board to the toplevel
1844 "Makefile" and to the "MAKEALL" script, using the existing
1845 entries as examples. Note that here and at many other places
1846 boards and other names are listed alphabetically sorted. Please
1848 2. Create a new directory to hold your board specific code. Add any
1849 files you need. In your board directory, you will need at least
1850 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1851 3. Create a new configuration file "include/configs/<board>.h" for
1853 3. If you're porting U-Boot to a new CPU, then also create a new
1854 directory to hold your CPU specific code. Add any files you need.
1855 4. Run "make <board>_config" with your new name.
1856 5. Type "make", and you should get a working "u-boot.srec" file
1857 to be installed on your target system.
1858 6. Debug and solve any problems that might arise.
1859 [Of course, this last step is much harder than it sounds.]
1862 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1863 ==============================================================
1865 If you have modified U-Boot sources (for instance added a new board
1866 or support for new devices, a new CPU, etc.) you are expected to
1867 provide feedback to the other developers. The feedback normally takes
1868 the form of a "patch", i. e. a context diff against a certain (latest
1869 official or latest in CVS) version of U-Boot sources.
1871 But before you submit such a patch, please verify that your modifi-
1872 cation did not break existing code. At least make sure that *ALL* of
1873 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1874 just run the "MAKEALL" script, which will configure and build U-Boot
1875 for ALL supported system. Be warned, this will take a while. You can
1876 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1877 environment variable to the script, i. e. to use the cross tools from
1878 MontaVista's Hard Hat Linux you can type
1880 CROSS_COMPILE=ppc_8xx- MAKEALL
1882 or to build on a native PowerPC system you can type
1884 CROSS_COMPILE=' ' MAKEALL
1886 See also "U-Boot Porting Guide" below.
1890 Monitor Commands - Overview:
1891 ============================
1893 go - start application at address 'addr'
1894 run - run commands in an environment variable
1895 bootm - boot application image from memory
1896 bootp - boot image via network using BootP/TFTP protocol
1897 tftpboot- boot image via network using TFTP protocol
1898 and env variables "ipaddr" and "serverip"
1899 (and eventually "gatewayip")
1900 rarpboot- boot image via network using RARP/TFTP protocol
1901 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1902 loads - load S-Record file over serial line
1903 loadb - load binary file over serial line (kermit mode)
1905 mm - memory modify (auto-incrementing)
1906 nm - memory modify (constant address)
1907 mw - memory write (fill)
1909 cmp - memory compare
1910 crc32 - checksum calculation
1911 imd - i2c memory display
1912 imm - i2c memory modify (auto-incrementing)
1913 inm - i2c memory modify (constant address)
1914 imw - i2c memory write (fill)
1915 icrc32 - i2c checksum calculation
1916 iprobe - probe to discover valid I2C chip addresses
1917 iloop - infinite loop on address range
1918 isdram - print SDRAM configuration information
1919 sspi - SPI utility commands
1920 base - print or set address offset
1921 printenv- print environment variables
1922 setenv - set environment variables
1923 saveenv - save environment variables to persistent storage
1924 protect - enable or disable FLASH write protection
1925 erase - erase FLASH memory
1926 flinfo - print FLASH memory information
1927 bdinfo - print Board Info structure
1928 iminfo - print header information for application image
1929 coninfo - print console devices and informations
1930 ide - IDE sub-system
1931 loop - infinite loop on address range
1932 mtest - simple RAM test
1933 icache - enable or disable instruction cache
1934 dcache - enable or disable data cache
1935 reset - Perform RESET of the CPU
1936 echo - echo args to console
1937 version - print monitor version
1938 help - print online help
1939 ? - alias for 'help'
1942 Monitor Commands - Detailed Description:
1943 ========================================
1947 For now: just type "help <command>".
1950 Environment Variables:
1951 ======================
1953 U-Boot supports user configuration using Environment Variables which
1954 can be made persistent by saving to Flash memory.
1956 Environment Variables are set using "setenv", printed using
1957 "printenv", and saved to Flash using "saveenv". Using "setenv"
1958 without a value can be used to delete a variable from the
1959 environment. As long as you don't save the environment you are
1960 working with an in-memory copy. In case the Flash area containing the
1961 environment is erased by accident, a default environment is provided.
1963 Some configuration options can be set using Environment Variables:
1965 baudrate - see CONFIG_BAUDRATE
1967 bootdelay - see CONFIG_BOOTDELAY
1969 bootcmd - see CONFIG_BOOTCOMMAND
1971 bootargs - Boot arguments when booting an RTOS image
1973 bootfile - Name of the image to load with TFTP
1975 autoload - if set to "no" (any string beginning with 'n'),
1976 "bootp" will just load perform a lookup of the
1977 configuration from the BOOTP server, but not try to
1978 load any image using TFTP
1980 autostart - if set to "yes", an image loaded using the "bootp",
1981 "rarpboot", "tftpboot" or "diskboot" commands will
1982 be automatically started (by internally calling
1985 If set to "no", a standalone image passed to the
1986 "bootm" command will be copied to the load address
1987 (and eventually uncompressed), but NOT be started.
1988 This can be used to load and uncompress arbitrary
1991 initrd_high - restrict positioning of initrd images:
1992 If this variable is not set, initrd images will be
1993 copied to the highest possible address in RAM; this
1994 is usually what you want since it allows for
1995 maximum initrd size. If for some reason you want to
1996 make sure that the initrd image is loaded below the
1997 CFG_BOOTMAPSZ limit, you can set this environment
1998 variable to a value of "no" or "off" or "0".
1999 Alternatively, you can set it to a maximum upper
2000 address to use (U-Boot will still check that it
2001 does not overwrite the U-Boot stack and data).
2003 For instance, when you have a system with 16 MB
2004 RAM, and want to reseve 4 MB from use by Linux,
2005 you can do this by adding "mem=12M" to the value of
2006 the "bootargs" variable. However, now you must make
2007 sure, that the initrd image is placed in the first
2008 12 MB as well - this can be done with
2010 setenv initrd_high 00c00000
2012 If you set initrd_high to 0xFFFFFFFF, this is an
2013 indication to U-Boot that all addresses are legal
2014 for the Linux kernel, including addresses in flash
2015 memory. In this case U-Boot will NOT COPY the
2016 ramdisk at all. This may be useful to reduce the
2017 boot time on your system, but requires that this
2018 feature is supported by your Linux kernel.
2020 ipaddr - IP address; needed for tftpboot command
2022 loadaddr - Default load address for commands like "bootp",
2023 "rarpboot", "tftpboot", "loadb" or "diskboot"
2025 loads_echo - see CONFIG_LOADS_ECHO
2027 serverip - TFTP server IP address; needed for tftpboot command
2029 bootretry - see CONFIG_BOOT_RETRY_TIME
2031 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2033 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2036 The following environment variables may be used and automatically
2037 updated by the network boot commands ("bootp" and "rarpboot"),
2038 depending the information provided by your boot server:
2040 bootfile - see above
2041 dnsip - IP address of your Domain Name Server
2042 gatewayip - IP address of the Gateway (Router) to use
2043 hostname - Target hostname
2045 netmask - Subnet Mask
2046 rootpath - Pathname of the root filesystem on the NFS server
2047 serverip - see above
2050 There are two special Environment Variables:
2052 serial# - contains hardware identification information such
2053 as type string and/or serial number
2054 ethaddr - Ethernet address
2056 These variables can be set only once (usually during manufacturing of
2057 the board). U-Boot refuses to delete or overwrite these variables
2058 once they have been set once.
2061 Further special Environment Variables:
2063 ver - Contains the U-Boot version string as printed
2064 with the "version" command. This variable is
2065 readonly (see CONFIG_VERSION_VARIABLE).
2068 Please note that changes to some configuration parameters may take
2069 only effect after the next boot (yes, that's just like Windoze :-).
2072 Command Line Parsing:
2073 =====================
2075 There are two different command line parsers available with U-Boot:
2076 the old "simple" one, and the much more pwerful "hush" shell:
2078 Old, simple command line parser:
2079 --------------------------------
2081 - supports environment variables (through setenv / saveenv commands)
2082 - several commands on one line, separated by ';'
2083 - variable substitution using "... $(name) ..." syntax
2084 - special characters ('$', ';') can be escaped by prefixing with '\',
2086 setenv bootcmd bootm \$(address)
2087 - You can also escape text by enclosing in single apostrophes, for example:
2088 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2093 - similar to Bourne shell, with control structures like
2094 if...then...else...fi, for...do...done; while...do...done,
2095 until...do...done, ...
2096 - supports environment ("global") variables (through setenv / saveenv
2097 commands) and local shell variables (through standard shell syntax
2098 "name=value"); only environment variables can be used with "run"
2104 (1) If a command line (or an environment variable executed by a "run"
2105 command) contains several commands separated by semicolon, and
2106 one of these commands fails, then the remaining commands will be
2109 (2) If you execute several variables with one call to run (i. e.
2110 calling run with a list af variables as arguments), any failing
2111 command will cause "run" to terminate, i. e. the remaining
2112 variables are not executed.
2114 Note for Redundant Ethernet Interfaces:
2115 =======================================
2117 Some boards come with redundand ethernet interfaces; U-Boot supports
2118 such configurations and is capable of automatic selection of a
2119 "working" interface when needed. MAC assignemnt works as follows:
2121 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2122 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2123 "eth1addr" (=>eth1), "eth2addr", ...
2125 If the network interface stores some valid MAC address (for instance
2126 in SROM), this is used as default address if there is NO correspon-
2127 ding setting in the environment; if the corresponding environment
2128 variable is set, this overrides the settings in the card; that means:
2130 o If the SROM has a valid MAC address, and there is no address in the
2131 environment, the SROM's address is used.
2133 o If there is no valid address in the SROM, and a definition in the
2134 environment exists, then the value from the environment variable is
2137 o If both the SROM and the environment contain a MAC address, and
2138 both addresses are the same, this MAC address is used.
2140 o If both the SROM and the environment contain a MAC address, and the
2141 addresses differ, the value from the environment is used and a
2144 o If neither SROM nor the environment contain a MAC address, an error
2152 The "boot" commands of this monitor operate on "image" files which
2153 can be basicly anything, preceeded by a special header; see the
2154 definitions in include/image.h for details; basicly, the header
2155 defines the following image properties:
2157 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2158 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2159 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2160 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
2161 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2162 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2163 Currently supported: PowerPC).
2164 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2165 Currently supported: uncompressed, gzip).
2171 The header is marked by a special Magic Number, and both the header
2172 and the data portions of the image are secured against corruption by
2179 Although U-Boot should support any OS or standalone application
2180 easily, Linux has always been in the focus during the design of
2183 U-Boot includes many features that so far have been part of some
2184 special "boot loader" code within the Linux kernel. Also, any
2185 "initrd" images to be used are no longer part of one big Linux image;
2186 instead, kernel and "initrd" are separate images. This implementation
2187 serves serveral purposes:
2189 - the same features can be used for other OS or standalone
2190 applications (for instance: using compressed images to reduce the
2191 Flash memory footprint)
2193 - it becomes much easier to port new Linux kernel versions because
2194 lots of low-level, hardware dependend stuff are done by U-Boot
2196 - the same Linux kernel image can now be used with different "initrd"
2197 images; of course this also means that different kernel images can
2198 be run with the same "initrd". This makes testing easier (you don't
2199 have to build a new "zImage.initrd" Linux image when you just
2200 change a file in your "initrd"). Also, a field-upgrade of the
2201 software is easier now.
2207 Porting Linux to U-Boot based systems:
2208 ---------------------------------------
2210 U-Boot cannot save you from doing all the necessary modifications to
2211 configure the Linux device drivers for use with your target hardware
2212 (no, we don't intend to provide a full virtual machine interface to
2215 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2217 Just make sure your machine specific header file (for instance
2218 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2219 Information structure as we define in include/u-boot.h, and make
2220 sure that your definition of IMAP_ADDR uses the same value as your
2221 U-Boot configuration in CFG_IMMR.
2224 Configuring the Linux kernel:
2225 -----------------------------
2227 No specific requirements for U-Boot. Make sure you have some root
2228 device (initial ramdisk, NFS) for your target system.
2231 Building a Linux Image:
2232 -----------------------
2234 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2235 not used. If you use recent kernel source, a new build target
2236 "uImage" will exist which automatically builds an image usable by
2237 U-Boot. Most older kernels also have support for a "pImage" target,
2238 which was introduced for our predecessor project PPCBoot and uses a
2239 100% compatible format.
2248 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2249 encapsulate a compressed Linux kernel image with header information,
2250 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2252 * build a standard "vmlinux" kernel image (in ELF binary format):
2254 * convert the kernel into a raw binary image:
2256 ${CROSS_COMPILE}-objcopy -O binary \
2257 -R .note -R .comment \
2258 -S vmlinux linux.bin
2260 * compress the binary image:
2264 * package compressed binary image for U-Boot:
2266 mkimage -A ppc -O linux -T kernel -C gzip \
2267 -a 0 -e 0 -n "Linux Kernel Image" \
2268 -d linux.bin.gz uImage
2271 The "mkimage" tool can also be used to create ramdisk images for use
2272 with U-Boot, either separated from the Linux kernel image, or
2273 combined into one file. "mkimage" encapsulates the images with a 64
2274 byte header containing information about target architecture,
2275 operating system, image type, compression method, entry points, time
2276 stamp, CRC32 checksums, etc.
2278 "mkimage" can be called in two ways: to verify existing images and
2279 print the header information, or to build new images.
2281 In the first form (with "-l" option) mkimage lists the information
2282 contained in the header of an existing U-Boot image; this includes
2283 checksum verification:
2285 tools/mkimage -l image
2286 -l ==> list image header information
2288 The second form (with "-d" option) is used to build a U-Boot image
2289 from a "data file" which is used as image payload:
2291 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2292 -n name -d data_file image
2293 -A ==> set architecture to 'arch'
2294 -O ==> set operating system to 'os'
2295 -T ==> set image type to 'type'
2296 -C ==> set compression type 'comp'
2297 -a ==> set load address to 'addr' (hex)
2298 -e ==> set entry point to 'ep' (hex)
2299 -n ==> set image name to 'name'
2300 -d ==> use image data from 'datafile'
2302 Right now, all Linux kernels use the same load address (0x00000000),
2303 but the entry point address depends on the kernel version:
2305 - 2.2.x kernels have the entry point at 0x0000000C,
2306 - 2.3.x and later kernels have the entry point at 0x00000000.
2308 So a typical call to build a U-Boot image would read:
2310 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2311 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2312 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2313 > examples/uImage.TQM850L
2314 Image Name: 2.4.4 kernel for TQM850L
2315 Created: Wed Jul 19 02:34:59 2000
2316 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2317 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2318 Load Address: 0x00000000
2319 Entry Point: 0x00000000
2321 To verify the contents of the image (or check for corruption):
2323 -> tools/mkimage -l examples/uImage.TQM850L
2324 Image Name: 2.4.4 kernel for TQM850L
2325 Created: Wed Jul 19 02:34:59 2000
2326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2327 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2328 Load Address: 0x00000000
2329 Entry Point: 0x00000000
2331 NOTE: for embedded systems where boot time is critical you can trade
2332 speed for memory and install an UNCOMPRESSED image instead: this
2333 needs more space in Flash, but boots much faster since it does not
2334 need to be uncompressed:
2336 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2337 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2338 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2339 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2340 > examples/uImage.TQM850L-uncompressed
2341 Image Name: 2.4.4 kernel for TQM850L
2342 Created: Wed Jul 19 02:34:59 2000
2343 Image Type: PowerPC Linux Kernel Image (uncompressed)
2344 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2345 Load Address: 0x00000000
2346 Entry Point: 0x00000000
2349 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2350 when your kernel is intended to use an initial ramdisk:
2352 -> tools/mkimage -n 'Simple Ramdisk Image' \
2353 > -A ppc -O linux -T ramdisk -C gzip \
2354 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2355 Image Name: Simple Ramdisk Image
2356 Created: Wed Jan 12 14:01:50 2000
2357 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2358 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2359 Load Address: 0x00000000
2360 Entry Point: 0x00000000
2363 Installing a Linux Image:
2364 -------------------------
2366 To downloading a U-Boot image over the serial (console) interface,
2367 you must convert the image to S-Record format:
2369 objcopy -I binary -O srec examples/image examples/image.srec
2371 The 'objcopy' does not understand the information in the U-Boot
2372 image header, so the resulting S-Record file will be relative to
2373 address 0x00000000. To load it to a given address, you need to
2374 specify the target address as 'offset' parameter with the 'loads'
2377 Example: install the image to address 0x40100000 (which on the
2378 TQM8xxL is in the first Flash bank):
2380 => erase 40100000 401FFFFF
2386 ## Ready for S-Record download ...
2387 ~>examples/image.srec
2388 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2390 15989 15990 15991 15992
2391 [file transfer complete]
2393 ## Start Addr = 0x00000000
2396 You can check the success of the download using the 'iminfo' command;
2397 this includes a checksum verification so you can be sure no data
2398 corruption happened:
2402 ## Checking Image at 40100000 ...
2403 Image Name: 2.2.13 for initrd on TQM850L
2404 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2405 Data Size: 335725 Bytes = 327 kB = 0 MB
2406 Load Address: 00000000
2407 Entry Point: 0000000c
2408 Verifying Checksum ... OK
2415 The "bootm" command is used to boot an application that is stored in
2416 memory (RAM or Flash). In case of a Linux kernel image, the contents
2417 of the "bootargs" environment variable is passed to the kernel as
2418 parameters. You can check and modify this variable using the
2419 "printenv" and "setenv" commands:
2422 => printenv bootargs
2423 bootargs=root=/dev/ram
2425 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2427 => printenv bootargs
2428 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2431 ## Booting Linux kernel at 40020000 ...
2432 Image Name: 2.2.13 for NFS on TQM850L
2433 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2434 Data Size: 381681 Bytes = 372 kB = 0 MB
2435 Load Address: 00000000
2436 Entry Point: 0000000c
2437 Verifying Checksum ... OK
2438 Uncompressing Kernel Image ... OK
2439 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
2440 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2441 time_init: decrementer frequency = 187500000/60
2442 Calibrating delay loop... 49.77 BogoMIPS
2443 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2446 If you want to boot a Linux kernel with initial ram disk, you pass
2447 the memory addreses of both the kernel and the initrd image (PPBCOOT
2448 format!) to the "bootm" command:
2450 => imi 40100000 40200000
2452 ## Checking Image at 40100000 ...
2453 Image Name: 2.2.13 for initrd on TQM850L
2454 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2455 Data Size: 335725 Bytes = 327 kB = 0 MB
2456 Load Address: 00000000
2457 Entry Point: 0000000c
2458 Verifying Checksum ... OK
2460 ## Checking Image at 40200000 ...
2461 Image Name: Simple Ramdisk Image
2462 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2463 Data Size: 566530 Bytes = 553 kB = 0 MB
2464 Load Address: 00000000
2465 Entry Point: 00000000
2466 Verifying Checksum ... OK
2468 => bootm 40100000 40200000
2469 ## Booting Linux kernel at 40100000 ...
2470 Image Name: 2.2.13 for initrd on TQM850L
2471 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2472 Data Size: 335725 Bytes = 327 kB = 0 MB
2473 Load Address: 00000000
2474 Entry Point: 0000000c
2475 Verifying Checksum ... OK
2476 Uncompressing Kernel Image ... OK
2477 ## Loading RAMDisk Image at 40200000 ...
2478 Image Name: Simple Ramdisk Image
2479 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2480 Data Size: 566530 Bytes = 553 kB = 0 MB
2481 Load Address: 00000000
2482 Entry Point: 00000000
2483 Verifying Checksum ... OK
2484 Loading Ramdisk ... OK
2485 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
2486 Boot arguments: root=/dev/ram
2487 time_init: decrementer frequency = 187500000/60
2488 Calibrating delay loop... 49.77 BogoMIPS
2490 RAMDISK: Compressed image found at block 0
2491 VFS: Mounted root (ext2 filesystem).
2495 More About U-Boot Image Types:
2496 ------------------------------
2498 U-Boot supports the following image types:
2500 "Standalone Programs" are directly runnable in the environment
2501 provided by U-Boot; it is expected that (if they behave
2502 well) you can continue to work in U-Boot after return from
2503 the Standalone Program.
2504 "OS Kernel Images" are usually images of some Embedded OS which
2505 will take over control completely. Usually these programs
2506 will install their own set of exception handlers, device
2507 drivers, set up the MMU, etc. - this means, that you cannot
2508 expect to re-enter U-Boot except by resetting the CPU.
2509 "RAMDisk Images" are more or less just data blocks, and their
2510 parameters (address, size) are passed to an OS kernel that is
2512 "Multi-File Images" contain several images, typically an OS
2513 (Linux) kernel image and one or more data images like
2514 RAMDisks. This construct is useful for instance when you want
2515 to boot over the network using BOOTP etc., where the boot
2516 server provides just a single image file, but you want to get
2517 for instance an OS kernel and a RAMDisk image.
2519 "Multi-File Images" start with a list of image sizes, each
2520 image size (in bytes) specified by an "uint32_t" in network
2521 byte order. This list is terminated by an "(uint32_t)0".
2522 Immediately after the terminating 0 follow the images, one by
2523 one, all aligned on "uint32_t" boundaries (size rounded up to
2524 a multiple of 4 bytes).
2526 "Firmware Images" are binary images containing firmware (like
2527 U-Boot or FPGA images) which usually will be programmed to
2530 "Script files" are command sequences that will be executed by
2531 U-Boot's command interpreter; this feature is especially
2532 useful when you configure U-Boot to use a real shell (hush)
2533 as command interpreter.
2539 One of the features of U-Boot is that you can dynamically load and
2540 run "standalone" applications, which can use some resources of
2541 U-Boot like console I/O functions or interrupt services.
2543 Two simple examples are included with the sources:
2548 'examples/hello_world.c' contains a small "Hello World" Demo
2549 application; it is automatically compiled when you build U-Boot.
2550 It's configured to run at address 0x00040004, so you can play with it
2554 ## Ready for S-Record download ...
2555 ~>examples/hello_world.srec
2556 1 2 3 4 5 6 7 8 9 10 11 ...
2557 [file transfer complete]
2559 ## Start Addr = 0x00040004
2561 => go 40004 Hello World! This is a test.
2562 ## Starting application at 0x00040004 ...
2573 Hit any key to exit ...
2575 ## Application terminated, rc = 0x0
2577 Another example, which demonstrates how to register a CPM interrupt
2578 handler with the U-Boot code, can be found in 'examples/timer.c'.
2579 Here, a CPM timer is set up to generate an interrupt every second.
2580 The interrupt service routine is trivial, just printing a '.'
2581 character, but this is just a demo program. The application can be
2582 controlled by the following keys:
2584 ? - print current values og the CPM Timer registers
2585 b - enable interrupts and start timer
2586 e - stop timer and disable interrupts
2587 q - quit application
2590 ## Ready for S-Record download ...
2591 ~>examples/timer.srec
2592 1 2 3 4 5 6 7 8 9 10 11 ...
2593 [file transfer complete]
2595 ## Start Addr = 0x00040004
2598 ## Starting application at 0x00040004 ...
2601 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2604 [q, b, e, ?] Set interval 1000000 us
2607 [q, b, e, ?] ........
2608 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2611 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2614 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2617 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2619 [q, b, e, ?] ...Stopping timer
2621 [q, b, e, ?] ## Application terminated, rc = 0x0
2628 Over time, many people have reported problems when trying to used the
2629 "minicom" terminal emulation program for serial download. I (wd)
2630 consider minicom to be broken, and recommend not to use it. Under
2631 Unix, I recommend to use C-Kermit for general purpose use (and
2632 especially for kermit binary protocol download ("loadb" command), and
2633 use "cu" for S-Record download ("loads" command).
2638 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2639 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2641 Building requires a cross environment; it is known to work on
2642 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2643 need gmake since the Makefiles are not compatible with BSD make).
2644 Note that the cross-powerpc package does not install include files;
2645 attempting to build U-Boot will fail because <machine/ansi.h> is
2646 missing. This file has to be installed and patched manually:
2648 # cd /usr/pkg/cross/powerpc-netbsd/include
2650 # ln -s powerpc machine
2651 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2652 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2654 Native builds *don't* work due to incompatibilities between native
2655 and U-Boot include files.
2657 Booting assumes that (the first part of) the image booted is a
2658 stage-2 loader which in turn loads and then invokes the kernel
2659 proper. Loader sources will eventually appear in the NetBSD source
2660 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2665 Implementation Internals:
2666 =========================
2668 The following is not intended to be a complete description of every
2669 implementation detail. However, it should help to understand the
2670 inner workings of U-Boot and make it easier to port it to custom
2674 Initial Stack, Global Data:
2675 ---------------------------
2677 The implementation of U-Boot is complicated by the fact that U-Boot
2678 starts running out of ROM (flash memory), usually without access to
2679 system RAM (because the memory controller is not initialized yet).
2680 This means that we don't have writable Data or BSS segments, and BSS
2681 is not initialized as zero. To be able to get a C environment working
2682 at all, we have to allocate at least a minimal stack. Implementation
2683 options for this are defined and restricted by the CPU used: Some CPU
2684 models provide on-chip memory (like the IMMR area on MPC8xx and
2685 MPC826x processors), on others (parts of) the data cache can be
2686 locked as (mis-) used as memory, etc.
2688 Chris Hallinan posted a good summy of these issues to the
2689 u-boot-users mailing list:
2691 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2693 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2696 Correct me if I'm wrong, folks, but the way I understand it
2697 is this: Using DCACHE as initial RAM for Stack, etc, does not
2698 require any physical RAM backing up the cache. The cleverness
2699 is that the cache is being used as a temporary supply of
2700 necessary storage before the SDRAM controller is setup. It's
2701 beyond the scope of this list to expain the details, but you
2702 can see how this works by studying the cache architecture and
2703 operation in the architecture and processor-specific manuals.
2705 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2706 is another option for the system designer to use as an
2707 initial stack/ram area prior to SDRAM being available. Either
2708 option should work for you. Using CS 4 should be fine if your
2709 board designers haven't used it for something that would
2710 cause you grief during the initial boot! It is frequently not
2713 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2714 with your processor/board/system design. The default value
2715 you will find in any recent u-boot distribution in
2716 Walnut405.h should work for you. I'd set it to a value larger
2717 than your SDRAM module. If you have a 64MB SDRAM module, set
2718 it above 400_0000. Just make sure your board has no resources
2719 that are supposed to respond to that address! That code in
2720 start.S has been around a while and should work as is when
2721 you get the config right.
2726 It is essential to remember this, since it has some impact on the C
2727 code for the initialization procedures:
2729 * Initialized global data (data segment) is read-only. Do not attempt
2732 * Do not use any unitialized global data (or implicitely initialized
2733 as zero data - BSS segment) at all - this is undefined, initiali-
2734 zation is performed later (when relocationg to RAM).
2736 * Stack space is very limited. Avoid big data buffers or things like
2739 Having only the stack as writable memory limits means we cannot use
2740 normal global data to share information beween the code. But it
2741 turned out that the implementation of U-Boot can be greatly
2742 simplified by making a global data structure (gd_t) available to all
2743 functions. We could pass a pointer to this data as argument to _all_
2744 functions, but this would bloat the code. Instead we use a feature of
2745 the GCC compiler (Global Register Variables) to share the data: we
2746 place a pointer (gd) to the global data into a register which we
2747 reserve for this purpose.
2749 When chosing a register for such a purpose we are restricted by the
2750 relevant (E)ABI specifications for the current architecture, and by
2751 GCC's implementation.
2753 For PowerPC, the following registers have specific use:
2756 R3-R4: parameter passing and return values
2757 R5-R10: parameter passing
2758 R13: small data area pointer
2762 (U-Boot also uses R14 as internal GOT pointer.)
2764 ==> U-Boot will use R29 to hold a pointer to the global data
2766 Note: on PPC, we could use a static initializer (since the
2767 address of the global data structure is known at compile time),
2768 but it turned out that reserving a register results in somewhat
2769 smaller code - although the code savings are not that big (on
2770 average for all boards 752 bytes for the whole U-Boot image,
2771 624 text + 127 data).
2773 On ARM, the following registers are used:
2775 R0: function argument word/integer result
2776 R1-R3: function argument word
2778 R10: stack limit (used only if stack checking if enabled)
2779 R11: argument (frame) pointer
2780 R12: temporary workspace
2783 R15: program counter
2785 ==> U-Boot will use R8 to hold a pointer to the global data
2792 U-Boot runs in system state and uses physical addresses, i.e. the
2793 MMU is not used either for address mapping nor for memory protection.
2795 The available memory is mapped to fixed addresses using the memory
2796 controller. In this process, a contiguous block is formed for each
2797 memory type (Flash, SDRAM, SRAM), even when it consists of several
2798 physical memory banks.
2800 U-Boot is installed in the first 128 kB of the first Flash bank (on
2801 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2802 booting and sizing and initializing DRAM, the code relocates itself
2803 to the upper end of DRAM. Immediately below the U-Boot code some
2804 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2805 configuration setting]. Below that, a structure with global Board
2806 Info data is placed, followed by the stack (growing downward).
2808 Additionally, some exception handler code is copied to the low 8 kB
2809 of DRAM (0x00000000 ... 0x00001FFF).
2811 So a typical memory configuration with 16 MB of DRAM could look like
2814 0x0000 0000 Exception Vector code
2817 0x0000 2000 Free for Application Use
2823 0x00FB FF20 Monitor Stack (Growing downward)
2824 0x00FB FFAC Board Info Data and permanent copy of global data
2825 0x00FC 0000 Malloc Arena
2828 0x00FE 0000 RAM Copy of Monitor Code
2829 ... eventually: LCD or video framebuffer
2830 ... eventually: pRAM (Protected RAM - unchanged by reset)
2831 0x00FF FFFF [End of RAM]
2834 System Initialization:
2835 ----------------------
2837 In the reset configuration, U-Boot starts at the reset entry point
2838 (on most PowerPC systens at address 0x00000100). Because of the reset
2839 configuration for CS0# this is a mirror of the onboard Flash memory.
2840 To be able to re-map memory U-Boot then jumps to it's link address.
2841 To be able to implement the initialization code in C, a (small!)
2842 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2843 which provide such a feature like MPC8xx or MPC8260), or in a locked
2844 part of the data cache. After that, U-Boot initializes the CPU core,
2845 the caches and the SIU.
2847 Next, all (potentially) available memory banks are mapped using a
2848 preliminary mapping. For example, we put them on 512 MB boundaries
2849 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2850 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2851 programmed for SDRAM access. Using the temporary configuration, a
2852 simple memory test is run that determines the size of the SDRAM
2855 When there is more than one SDRAM bank, and the banks are of
2856 different size, the larger is mapped first. For equal size, the first
2857 bank (CS2#) is mapped first. The first mapping is always for address
2858 0x00000000, with any additional banks following immediately to create
2859 contiguous memory starting from 0.
2861 Then, the monitor installs itself at the upper end of the SDRAM area
2862 and allocates memory for use by malloc() and for the global Board
2863 Info data; also, the exception vector code is copied to the low RAM
2864 pages, and the final stack is set up.
2866 Only after this relocation will you have a "normal" C environment;
2867 until that you are restricted in several ways, mostly because you are
2868 running from ROM, and because the code will have to be relocated to a
2872 U-Boot Porting Guide:
2873 ----------------------
2875 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2879 int main (int argc, char *argv[])
2881 sighandler_t no_more_time;
2883 signal (SIGALRM, no_more_time);
2884 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2886 if (available_money > available_manpower) {
2887 pay consultant to port U-Boot;
2891 Download latest U-Boot source;
2893 Subscribe to u-boot-users mailing list;
2896 email ("Hi, I am new to U-Boot, how do I get started?");
2900 Read the README file in the top level directory;
2901 Read http://www.denx.de/re/DPLG.html
2902 Read the source, Luke;
2905 if (available_money > toLocalCurrency ($2500)) {
2908 Add a lot of aggravation and time;
2911 Create your own board support subdirectory;
2913 Create your own board config file;
2917 Add / modify source code;
2921 email ("Hi, I am having problems...");
2923 Send patch file to Wolfgang;
2928 void no_more_time (int sig)
2938 All contributions to U-Boot should conform to the Linux kernel
2939 coding style; see the file "Documentation/CodingStyle" in your Linux
2940 kernel source directory.
2942 Please note that U-Boot is implemented in C (and to some small parts
2943 in Assembler); no C++ is used, so please do not use C++ style
2944 comments (//) in your code.
2946 Submissions which do not conform to the standards may be returned
2947 with a request to reformat the changes.
2953 Since the number of patches for U-Boot is growing, we need to
2954 establish some rules. Submissions which do not conform to these rules
2955 may be rejected, even when they contain important and valuable stuff.
2958 When you send a patch, please include the following information with
2961 * For bug fixes: a description of the bug and how your patch fixes
2962 this bug. Please try to include a way of demonstrating that the
2963 patch actually fixes something.
2965 * For new features: a description of the feature and your
2968 * A CHANGELOG entry as plaintext (separate from the patch)
2970 * For major contributions, your entry to the CREDITS file
2972 * When you add support for a new board, don't forget to add this
2973 board to the MAKEALL script, too.
2975 * If your patch adds new configuration options, don't forget to
2976 document these in the README file.
2978 * The patch itself. If you are accessing the CVS repository use "cvs
2979 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2980 version of diff does not support these options, then get the latest
2981 version of GNU diff.
2983 We accept patches as plain text, MIME attachments or as uuencoded
2988 * Before sending the patch, run the MAKEALL script on your patched
2989 source tree and make sure that no errors or warnings are reported
2990 for any of the boards.
2992 * Keep your modifications to the necessary minimum: A patch
2993 containing several unrelated changes or arbitrary reformats will be
2994 returned with a request to re-formatting / split it.
2996 * If you modify existing code, make sure that your new code does not
2997 add to the memory footprint of the code ;-) Small is beautiful!
2998 When adding new features, these should compile conditionally only
2999 (using #ifdef), and the resulting code with the new feature
3000 disabled must not need more memory than the old code without your
projects / u-boot.git / blob