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/at91rm9200dk Files specific to AT91RM9200DK boards
155 - board/c2mon Files specific to c2mon boards
156 - board/cmi Files specific to cmi boards
157 - board/cogent Files specific to Cogent boards
158 (need further configuration)
159 Files specific to CPCIISER4 boards
160 - board/cpu86 Files specific to CPU86 boards
161 - board/cray/ Files specific to boards manufactured by Cray
162 - board/cray/L1 Files specific to L1 boards
163 - board/cu824 Files specific to CU824 boards
164 - board/ebony Files specific to IBM Ebony board
165 - board/eric Files specific to ERIC boards
166 - board/esd/ Files specific to boards manufactured by ESD
167 - board/esd/adciop Files specific to ADCIOP boards
168 - board/esd/ar405 Files specific to AR405 boards
169 - board/esd/canbt Files specific to CANBT boards
170 - board/esd/cpci405 Files specific to CPCI405 boards
171 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
172 - board/esd/common Common files for ESD boards
173 - board/esd/dasa_sim Files specific to DASA_SIM boards
174 - board/esd/du405 Files specific to DU405 boards
175 - board/esd/ocrtc Files specific to OCRTC boards
176 - board/esd/pci405 Files specific to PCI405 boards
178 Files specific to ESTEEM192E boards
179 - board/etx094 Files specific to ETX_094 boards
181 Files specific to EVB64260 boards
182 - board/fads Files specific to FADS boards
183 - board/flagadm Files specific to FLAGADM boards
184 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
185 - board/genietv Files specific to GENIETV boards
186 - board/gth Files specific to GTH boards
187 - board/hermes Files specific to HERMES boards
188 - board/hymod Files specific to HYMOD boards
189 - board/icu862 Files specific to ICU862 boards
190 - board/ip860 Files specific to IP860 boards
192 Files specific to Interphase4539 boards
193 - board/ivm Files specific to IVMS8/IVML24 boards
194 - board/lantec Files specific to LANTEC boards
195 - board/lwmon Files specific to LWMON boards
196 - board/mbx8xx Files specific to MBX boards
198 Files specific to MMPC8260ADS boards
199 - board/mpl/ Files specific to boards manufactured by MPL
200 - board/mpl/common Common files for MPL boards
201 - board/mpl/pip405 Files specific to PIP405 boards
202 - board/mpl/mip405 Files specific to MIP405 boards
203 - board/musenki Files specific to MUSEKNI boards
204 - board/mvs1 Files specific to MVS1 boards
205 - board/nx823 Files specific to NX823 boards
206 - board/oxc Files specific to OXC boards
207 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
208 - board/pm826 Files specific to PM826 boards
210 Files specific to PPMC8260 boards
212 Files specific to RPXsuper boards
214 Files specific to RSDproto boards
216 Files specific to Sandpoint boards
217 - board/sbc8260 Files specific to SBC8260 boards
218 - board/sacsng Files specific to SACSng boards
219 - board/siemens Files specific to boards manufactured by Siemens AG
220 - board/siemens/CCM Files specific to CCM boards
221 - board/siemens/IAD210 Files specific to IAD210 boards
222 - board/siemens/SCM Files specific to SCM boards
223 - board/siemens/pcu_e Files specific to PCU_E boards
224 - board/sixnet Files specific to SIXNET boards
225 - board/spd8xx Files specific to SPD8xxTS boards
226 - board/tqm8260 Files specific to TQM8260 boards
227 - board/tqm8xx Files specific to TQM8xxL boards
228 - board/w7o Files specific to W7O boards
230 Files specific to Walnut405 boards
231 - board/westel/ Files specific to boards manufactured by Westel Wireless
232 - board/westel/amx860 Files specific to AMX860 boards
233 - board/utx8245 Files specific to UTX8245 boards
235 Software Configuration:
236 =======================
238 Configuration is usually done using C preprocessor defines; the
239 rationale behind that is to avoid dead code whenever possible.
241 There are two classes of configuration variables:
243 * Configuration _OPTIONS_:
244 These are selectable by the user and have names beginning with
247 * Configuration _SETTINGS_:
248 These depend on the hardware etc. and should not be meddled with if
249 you don't know what you're doing; they have names beginning with
252 Later we will add a configuration tool - probably similar to or even
253 identical to what's used for the Linux kernel. Right now, we have to
254 do the configuration by hand, which means creating some symbolic
255 links and editing some configuration files. We use the TQM8xxL boards
259 Selection of Processor Architecture and Board Type:
260 ---------------------------------------------------
262 For all supported boards there are ready-to-use default
263 configurations available; just type "make <board_name>_config".
265 Example: For a TQM823L module type:
270 For the Cogent platform, you need to specify the cpu type as well;
271 e.g. "make cogent_mpc8xx_config". And also configure the cogent
272 directory according to the instructions in cogent/README.
275 Configuration Options:
276 ----------------------
278 Configuration depends on the combination of board and CPU type; all
279 such information is kept in a configuration file
280 "include/configs/<board_name>.h".
282 Example: For a TQM823L module, all configuration settings are in
283 "include/configs/TQM823L.h".
286 Many of the options are named exactly as the corresponding Linux
287 kernel configuration options. The intention is to make it easier to
288 build a config tool - later.
291 The following options need to be configured:
293 - CPU Type: Define exactly one of
297 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
299 or CONFIG_MPC824X, CONFIG_MPC8260
312 - Board Type: Define exactly one of
314 PowerPC based boards:
315 ---------------------
317 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
318 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
319 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
320 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
321 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
322 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
323 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
324 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
325 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
326 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
327 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
328 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
329 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
330 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
331 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
332 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
333 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
334 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
335 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
336 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
337 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
338 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
339 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
340 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
341 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
342 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
343 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
344 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
345 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
346 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
347 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
348 CONFIG_NETVIA, CONFIG_RBC823
353 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
354 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
355 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
356 CONFIG_TRAB, CONFIG_AT91RM9200DK
359 - CPU Module Type: (if CONFIG_COGENT is defined)
360 Define exactly one of
362 --- FIXME --- not tested yet:
363 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
364 CONFIG_CMA287_23, CONFIG_CMA287_50
366 - Motherboard Type: (if CONFIG_COGENT is defined)
367 Define exactly one of
368 CONFIG_CMA101, CONFIG_CMA102
370 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
371 Define one or more of
374 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
375 Define one or more of
376 CONFIG_LCD_HEARTBEAT - update a character position on
377 the lcd display every second with
380 - MPC824X Family Member (if CONFIG_MPC824X is defined)
381 Define exactly one of
382 CONFIG_MPC8240, CONFIG_MPC8245
384 - 8xx CPU Options: (if using an 8xx cpu)
385 Define one or more of
386 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
387 no 32KHz reference PIT/RTC clock
392 U-Boot stores all clock information in Hz
393 internally. For binary compatibility with older Linux
394 kernels (which expect the clocks passed in the
395 bd_info data to be in MHz) the environment variable
396 "clocks_in_mhz" can be defined so that U-Boot
397 converts clock data to MHZ before passing it to the
400 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
401 "clocks_in_mhz=1" is automatically included in the
405 Depending on board, define exactly one serial port
406 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
407 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
408 console by defining CONFIG_8xx_CONS_NONE
410 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
411 port routines must be defined elsewhere
412 (i.e. serial_init(), serial_getc(), ...)
415 Enables console device for a color framebuffer. Needs following
416 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
417 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
419 VIDEO_HW_RECTFILL graphic chip supports
422 VIDEO_HW_BITBLT graphic chip supports
423 bit-blit (cf. smiLynxEM)
424 VIDEO_VISIBLE_COLS visible pixel columns
426 VIDEO_VISIBLE_ROWS visible pixel rows
427 VIDEO_PIXEL_SIZE bytes per pixel
428 VIDEO_DATA_FORMAT graphic data format
429 (0-5, cf. cfb_console.c)
430 VIDEO_FB_ADRS framebuffer address
431 VIDEO_KBD_INIT_FCT keyboard int fct
432 (i.e. i8042_kbd_init())
433 VIDEO_TSTC_FCT test char fct
435 VIDEO_GETC_FCT get char fct
437 CONFIG_CONSOLE_CURSOR cursor drawing on/off
438 (requires blink timer
440 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
441 CONFIG_CONSOLE_TIME display time/date info in
443 (requires CFG_CMD_DATE)
444 CONFIG_VIDEO_LOGO display Linux logo in
446 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
447 linux_logo.h for logo.
448 Requires CONFIG_VIDEO_LOGO
449 CONFIG_CONSOLE_EXTRA_INFO
450 addional board info beside
453 When CONFIG_CFB_CONSOLE is defined, video console is
454 default i/o. Serial console can be forced with
455 environment 'console=serial'.
458 CONFIG_BAUDRATE - in bps
459 Select one of the baudrates listed in
460 CFG_BAUDRATE_TABLE, see below.
462 - Interrupt driven serial port input:
463 CONFIG_SERIAL_SOFTWARE_FIFO
466 Use an interrupt handler for receiving data on the
467 serial port. It also enables using hardware handshake
468 (RTS/CTS) and UART's built-in FIFO. Set the number of
469 bytes the interrupt driven input buffer should have.
471 Set to 0 to disable this feature (this is the default).
472 This will also disable hardware handshake.
474 - Console UART Number:
478 If defined internal UART1 (and not UART0) is used
479 as default U-Boot console.
481 - Boot Delay: CONFIG_BOOTDELAY - in seconds
482 Delay before automatically booting the default image;
483 set to -1 to disable autoboot.
485 See doc/README.autoboot for these options that
486 work with CONFIG_BOOTDELAY. None are required.
487 CONFIG_BOOT_RETRY_TIME
488 CONFIG_BOOT_RETRY_MIN
489 CONFIG_AUTOBOOT_KEYED
490 CONFIG_AUTOBOOT_PROMPT
491 CONFIG_AUTOBOOT_DELAY_STR
492 CONFIG_AUTOBOOT_STOP_STR
493 CONFIG_AUTOBOOT_DELAY_STR2
494 CONFIG_AUTOBOOT_STOP_STR2
495 CONFIG_ZERO_BOOTDELAY_CHECK
496 CONFIG_RESET_TO_RETRY
500 Only needed when CONFIG_BOOTDELAY is enabled;
501 define a command string that is automatically executed
502 when no character is read on the console interface
503 within "Boot Delay" after reset.
506 This can be used to pass arguments to the bootm
507 command. The value of CONFIG_BOOTARGS goes into the
508 environment value "bootargs".
510 CONFIG_RAMBOOT and CONFIG_NFSBOOT
511 The value of these goes into the environment as
512 "ramboot" and "nfsboot" respectively, and can be used
513 as a convenience, when switching between booting from
519 When this option is #defined, the existence of the
520 environment variable "preboot" will be checked
521 immediately before starting the CONFIG_BOOTDELAY
522 countdown and/or running the auto-boot command resp.
523 entering interactive mode.
525 This feature is especially useful when "preboot" is
526 automatically generated or modified. For an example
527 see the LWMON board specific code: here "preboot" is
528 modified when the user holds down a certain
529 combination of keys on the (special) keyboard when
532 - Serial Download Echo Mode:
534 If defined to 1, all characters received during a
535 serial download (using the "loads" command) are
536 echoed back. This might be needed by some terminal
537 emulations (like "cu"), but may as well just take
538 time on others. This setting #define's the initial
539 value of the "loads_echo" environment variable.
541 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
543 Select one of the baudrates listed in
544 CFG_BAUDRATE_TABLE, see below.
548 Most monitor functions can be selected (or
549 de-selected) by adjusting the definition of
550 CONFIG_COMMANDS; to select individual functions,
551 #define CONFIG_COMMANDS by "OR"ing any of the
554 #define enables commands:
555 -------------------------
556 CFG_CMD_ASKENV * ask for env variable
558 CFG_CMD_BEDBUG Include BedBug Debugger
560 CFG_CMD_CACHE icache, dcache
561 CFG_CMD_CONSOLE coninfo
562 CFG_CMD_DATE * support for RTC, date/time...
563 CFG_CMD_DHCP DHCP support
564 CFG_CMD_ECHO * echo arguments
565 CFG_CMD_EEPROM * EEPROM read/write support
566 CFG_CMD_ELF bootelf, bootvx
568 CFG_CMD_FDC * Floppy Disk Support
569 CFG_CMD_FAT FAT partition support
570 CFG_CMD_FDOS * Dos diskette Support
571 CFG_CMD_FLASH flinfo, erase, protect
572 CFG_CMD_FPGA FPGA device initialization support
573 CFG_CMD_I2C * I2C serial bus support
574 CFG_CMD_IDE * IDE harddisk support
576 CFG_CMD_IMMAP * IMMR dump support
577 CFG_CMD_IRQ * irqinfo
581 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
583 CFG_CMD_MMC MMC memory mapped support
584 CFG_CMD_MII MII utility commands
585 CFG_CMD_NET bootp, tftpboot, rarpboot
586 CFG_CMD_PCI * pciinfo
587 CFG_CMD_PCMCIA * PCMCIA support
588 CFG_CMD_REGINFO * Register dump
589 CFG_CMD_RUN run command in env variable
590 CFG_CMD_SCSI * SCSI Support
591 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
592 CFG_CMD_SPI * SPI serial bus support
593 CFG_CMD_USB * USB support
594 CFG_CMD_BSP * Board SPecific functions
595 -----------------------------------------------
598 CFG_CMD_DFL Default configuration; at the moment
599 this is includes all commands, except
600 the ones marked with "*" in the list
603 If you don't define CONFIG_COMMANDS it defaults to
604 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
605 override the default settings in the respective
608 EXAMPLE: If you want all functions except of network
609 support you can write:
611 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
614 Note: Don't enable the "icache" and "dcache" commands
615 (configuration option CFG_CMD_CACHE) unless you know
616 what you (and your U-Boot users) are doing. Data
617 cache cannot be enabled on systems like the 8xx or
618 8260 (where accesses to the IMMR region must be
619 uncached), and it cannot be disabled on all other
620 systems where we (mis-) use the data cache to hold an
621 initial stack and some data.
624 XXX - this list needs to get updated!
628 If this variable is defined, it enables watchdog
629 support. There must support in the platform specific
630 code for a watchdog. For the 8xx and 8260 CPUs, the
631 SIU Watchdog feature is enabled in the SYPCR
635 CONFIG_VERSION_VARIABLE
636 If this variable is defined, an environment variable
637 named "ver" is created by U-Boot showing the U-Boot
638 version as printed by the "version" command.
639 This variable is readonly.
643 When CFG_CMD_DATE is selected, the type of the RTC
644 has to be selected, too. Define exactly one of the
647 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
648 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
649 CONFIG_RTC_MC146818 - use MC146818 RTC
650 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
651 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
652 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
653 CONFIG_RTC_DS164x - use Dallas DS164x RTC
657 When CONFIG_TIMESTAMP is selected, the timestamp
658 (date and time) of an image is printed by image
659 commands like bootm or iminfo. This option is
660 automatically enabled when you select CFG_CMD_DATE .
663 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
664 and/or CONFIG_ISO_PARTITION
666 If IDE or SCSI support is enabled (CFG_CMD_IDE or
667 CFG_CMD_SCSI) you must configure support for at least
668 one partition type as well.
671 CONFIG_IDE_RESET_ROUTINE
673 Set this to define that instead of a reset Pin, the
674 routine ide_set_reset(int idereset) will be used.
679 Set this to enable ATAPI support.
682 At the moment only there is only support for the
683 SYM53C8XX SCSI controller; define
684 CONFIG_SCSI_SYM53C8XX to enable it.
686 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
687 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
688 CFG_SCSI_MAX_LUN] can be adjusted to define the
689 maximum numbers of LUNs, SCSI ID's and target
691 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
693 - NETWORK Support (PCI):
695 Support for Intel 8254x gigabit chips.
698 Support for Intel 82557/82559/82559ER chips.
699 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
700 write routine for first time initialisation.
703 Support for Digital 2114x chips.
704 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
705 modem chip initialisation (KS8761/QS6611).
708 Support for National dp83815 chips.
711 Support for National dp8382[01] gigabit chips.
713 - NETWORK Support (other):
715 CONFIG_DRIVER_LAN91C96
716 Support for SMSC's LAN91C96 chips.
719 Define this to hold the physical address
720 of the LAN91C96's I/O space
722 CONFIG_LAN91C96_USE_32_BIT
723 Define this to enable 32 bit addressing
726 At the moment only the UHCI host controller is
727 supported (PIP405, MIP405); define
728 CONFIG_USB_UHCI to enable it.
729 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
730 end define CONFIG_USB_STORAGE to enable the USB
733 Supported are USB Keyboards and USB Floppy drives
737 The MMC controller on the Intel PXA is supported. To
738 enable this define CONFIG_MMC. The MMC can be
739 accessed from the boot prompt by mapping the device
740 to physical memory similar to flash. Command line is
741 enabled with CFG_CMD_MMC. The MMC driver also works with
742 the FAT fs. This is enabled with CFG_CMD_FAT.
747 Define this to enable standard (PC-Style) keyboard
751 Standard PC keyboard driver with US (is default) and
752 GERMAN key layout (switch via environment 'keymap=de') support.
753 Export function i8042_kbd_init, i8042_tstc and i8042_getc
754 for cfb_console. Supports cursor blinking.
759 Define this to enable video support (for output to
764 Enable Chips & Technologies 69000 Video chip
766 CONFIG_VIDEO_SMI_LYNXEM
767 Enable Silicon Motion SMI 712/710/810 Video chip
768 Videomode are selected via environment 'videomode' with
769 standard LiLo mode numbers.
770 Following modes are supported (* is default):
772 800x600 1024x768 1280x1024
773 256 (8bit) 303* 305 307
774 65536 (16bit) 314 317 31a
775 16,7 Mill (24bit) 315 318 31b
776 (i.e. setenv videomode 317; saveenv; reset;)
778 CONFIG_VIDEO_SED13806
779 Enable Epson SED13806 driver. This driver supports 8bpp
780 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
781 or CONFIG_VIDEO_SED13806_16BPP
786 Define this to enable a custom keyboard support.
787 This simply calls drv_keyboard_init() which must be
788 defined in your board-specific files.
789 The only board using this so far is RBC823.
791 - LCD Support: CONFIG_LCD
793 Define this to enable LCD support (for output to LCD
794 display); also select one of the supported displays
795 by defining one of these:
797 CONFIG_NEC_NL6648AC33:
799 NEC NL6648AC33-18. Active, color, single scan.
801 CONFIG_NEC_NL6648BC20
803 NEC NL6648BC20-08. 6.5", 640x480.
804 Active, color, single scan.
808 Sharp 320x240. Active, color, single scan.
809 It isn't 16x9, and I am not sure what it is.
811 CONFIG_SHARP_LQ64D341
813 Sharp LQ64D341 display, 640x480.
814 Active, color, single scan.
818 HLD1045 display, 640x480.
819 Active, color, single scan.
823 Optrex CBL50840-2 NF-FW 99 22 M5
825 Hitachi LMG6912RPFC-00T
829 320x240. Black & white.
831 Normally display is black on white background; define
832 CFG_WHITE_ON_BLACK to get it inverted.
834 - Spash Screen Support: CONFIG_SPLASH_SCREEN
836 If this option is set, the environment is checked for
837 a variable "splashimage". If found, the usual display
838 of logo, copyright and system information on the LCD
839 is supressed and the BMP image at the address
840 specified in "splashimage" is loaded instead. The
841 console is redirected to the "nulldev", too. This
842 allows for a "silent" boot where a splash screen is
843 loaded very quickly after power-on.
851 Define a default value for ethernet address to use
852 for the respective ethernet interface, in case this
853 is not determined automatically.
858 Define a default value for the IP address to use for
859 the default ethernet interface, in case this is not
860 determined through e.g. bootp.
865 Defines a default value for theIP address of a TFTP
866 server to contact when using the "tftboot" command.
868 - BOOTP Recovery Mode:
869 CONFIG_BOOTP_RANDOM_DELAY
871 If you have many targets in a network that try to
872 boot using BOOTP, you may want to avoid that all
873 systems send out BOOTP requests at precisely the same
874 moment (which would happen for instance at recovery
875 from a power failure, when all systems will try to
876 boot, thus flooding the BOOTP server. Defining
877 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
878 inserted before sending out BOOTP requests. The
879 following delays are insterted then:
881 1st BOOTP request: delay 0 ... 1 sec
882 2nd BOOTP request: delay 0 ... 2 sec
883 3rd BOOTP request: delay 0 ... 4 sec
885 BOOTP requests: delay 0 ... 8 sec
887 - Status LED: CONFIG_STATUS_LED
889 Several configurations allow to display the current
890 status using a LED. For instance, the LED will blink
891 fast while running U-Boot code, stop blinking as
892 soon as a reply to a BOOTP request was received, and
893 start blinking slow once the Linux kernel is running
894 (supported by a status LED driver in the Linux
895 kernel). Defining CONFIG_STATUS_LED enables this
898 - CAN Support: CONFIG_CAN_DRIVER
900 Defining CONFIG_CAN_DRIVER enables CAN driver support
901 on those systems that support this (optional)
902 feature, like the TQM8xxL modules.
904 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
906 Enables I2C serial bus commands. If this is selected,
907 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
908 to include the appropriate I2C driver.
910 See also: common/cmd_i2c.c for a description of the
911 command line interface.
916 Selects the CPM hardware driver for I2C.
920 Use software (aka bit-banging) driver instead of CPM
921 or similar hardware support for I2C. This is configured
922 via the following defines.
926 (Optional). Any commands necessary to enable I2C
927 controller or configure ports.
931 (Only for MPC8260 CPU). The I/O port to use (the code
932 assumes both bits are on the same port). Valid values
933 are 0..3 for ports A..D.
937 The code necessary to make the I2C data line active
938 (driven). If the data line is open collector, this
943 The code necessary to make the I2C data line tri-stated
944 (inactive). If the data line is open collector, this
949 Code that returns TRUE if the I2C data line is high,
954 If <bit> is TRUE, sets the I2C data line high. If it
955 is FALSE, it clears it (low).
959 If <bit> is TRUE, sets the I2C clock line high. If it
960 is FALSE, it clears it (low).
964 This delay is invoked four times per clock cycle so this
965 controls the rate of data transfer. The data rate thus
966 is 1 / (I2C_DELAY * 4).
970 When a board is reset during an i2c bus transfer
971 chips might think that the current transfer is still
972 in progress. On some boards it is possible to access
973 the i2c SCLK line directly, either by using the
974 processor pin as a GPIO or by having a second pin
975 connected to the bus. If this option is defined a
976 custom i2c_init_board() routine in boards/xxx/board.c
977 is run early in the boot sequence.
979 - SPI Support: CONFIG_SPI
981 Enables SPI driver (so far only tested with
982 SPI EEPROM, also an instance works with Crystal A/D and
983 D/As on the SACSng board)
987 Enables extended (16-bit) SPI EEPROM addressing.
988 (symmetrical to CONFIG_I2C_X)
992 Enables a software (bit-bang) SPI driver rather than
993 using hardware support. This is a general purpose
994 driver that only requires three general I/O port pins
995 (two outputs, one input) to function. If this is
996 defined, the board configuration must define several
997 SPI configuration items (port pins to use, etc). For
998 an example, see include/configs/sacsng.h.
1000 - FPGA Support: CONFIG_FPGA_COUNT
1002 Specify the number of FPGA devices to support.
1006 Used to specify the types of FPGA devices. For
1008 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1010 CFG_FPGA_PROG_FEEDBACK
1012 Enable printing of hash marks during FPGA
1017 Enable checks on FPGA configuration interface busy
1018 status by the configuration function. This option
1019 will require a board or device specific function to
1024 If defined, a function that provides delays in the
1025 FPGA configuration driver.
1027 CFG_FPGA_CHECK_CTRLC
1029 Allow Control-C to interrupt FPGA configuration
1031 CFG_FPGA_CHECK_ERROR
1033 Check for configuration errors during FPGA bitfile
1034 loading. For example, abort during Virtex II
1035 configuration if the INIT_B line goes low (which
1036 indicated a CRC error).
1040 Maximum time to wait for the INIT_B line to deassert
1041 after PROB_B has been deasserted during a Virtex II
1042 FPGA configuration sequence. The default time is 500 mS.
1046 Maximum time to wait for BUSY to deassert during
1047 Virtex II FPGA configuration. The default is 5 mS.
1049 CFG_FPGA_WAIT_CONFIG
1051 Time to wait after FPGA configuration. The default is
1054 - FPGA Support: CONFIG_FPGA_COUNT
1056 Specify the number of FPGA devices to support.
1060 Used to specify the types of FPGA devices. For example,
1061 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1063 CFG_FPGA_PROG_FEEDBACK
1065 Enable printing of hash marks during FPGA configuration.
1069 Enable checks on FPGA configuration interface busy
1070 status by the configuration function. This option
1071 will require a board or device specific function to
1076 If defined, a function that provides delays in the FPGA
1077 configuration driver.
1079 CFG_FPGA_CHECK_CTRLC
1080 Allow Control-C to interrupt FPGA configuration
1082 CFG_FPGA_CHECK_ERROR
1084 Check for configuration errors during FPGA bitfile
1085 loading. For example, abort during Virtex II
1086 configuration if the INIT_B line goes low (which
1087 indicated a CRC error).
1091 Maximum time to wait for the INIT_B line to deassert
1092 after PROB_B has been deasserted during a Virtex II
1093 FPGA configuration sequence. The default time is 500
1098 Maximum time to wait for BUSY to deassert during
1099 Virtex II FPGA configuration. The default is 5 mS.
1101 CFG_FPGA_WAIT_CONFIG
1103 Time to wait after FPGA configuration. The default is
1106 - Configuration Management:
1109 If defined, this string will be added to the U-Boot
1110 version information (U_BOOT_VERSION)
1112 - Vendor Parameter Protection:
1114 U-Boot considers the values of the environment
1115 variables "serial#" (Board Serial Number) and
1116 "ethaddr" (Ethernet Address) to bb parameters that
1117 are set once by the board vendor / manufacturer, and
1118 protects these variables from casual modification by
1119 the user. Once set, these variables are read-only,
1120 and write or delete attempts are rejected. You can
1121 change this behviour:
1123 If CONFIG_ENV_OVERWRITE is #defined in your config
1124 file, the write protection for vendor parameters is
1125 completely disabled. Anybody can change or delete
1128 Alternatively, if you #define _both_ CONFIG_ETHADDR
1129 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1130 ethernet address is installed in the environment,
1131 which can be changed exactly ONCE by the user. [The
1132 serial# is unaffected by this, i. e. it remains
1138 Define this variable to enable the reservation of
1139 "protected RAM", i. e. RAM which is not overwritten
1140 by U-Boot. Define CONFIG_PRAM to hold the number of
1141 kB you want to reserve for pRAM. You can overwrite
1142 this default value by defining an environment
1143 variable "pram" to the number of kB you want to
1144 reserve. Note that the board info structure will
1145 still show the full amount of RAM. If pRAM is
1146 reserved, a new environment variable "mem" will
1147 automatically be defined to hold the amount of
1148 remaining RAM in a form that can be passed as boot
1149 argument to Linux, for instance like that:
1151 setenv bootargs ... mem=\$(mem)
1154 This way you can tell Linux not to use this memory,
1155 either, which results in a memory region that will
1156 not be affected by reboots.
1158 *WARNING* If your board configuration uses automatic
1159 detection of the RAM size, you must make sure that
1160 this memory test is non-destructive. So far, the
1161 following board configurations are known to be
1164 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1165 HERMES, IP860, RPXlite, LWMON, LANTEC,
1166 PCU_E, FLAGADM, TQM8260
1171 Define this variable to stop the system in case of a
1172 fatal error, so that you have to reset it manually.
1173 This is probably NOT a good idea for an embedded
1174 system where you want to system to reboot
1175 automatically as fast as possible, but it may be
1176 useful during development since you can try to debug
1177 the conditions that lead to the situation.
1179 CONFIG_NET_RETRY_COUNT
1181 This variable defines the number of retries for
1182 network operations like ARP, RARP, TFTP, or BOOTP
1183 before giving up the operation. If not defined, a
1184 default value of 5 is used.
1186 - Command Interpreter:
1189 Define this variable to enable the "hush" shell (from
1190 Busybox) as command line interpreter, thus enabling
1191 powerful command line syntax like
1192 if...then...else...fi conditionals or `&&' and '||'
1193 constructs ("shell scripts").
1195 If undefined, you get the old, much simpler behaviour
1196 with a somewhat smaller memory footprint.
1201 This defines the secondary prompt string, which is
1202 printed when the command interpreter needs more input
1203 to complete a command. Usually "> ".
1207 In the current implementation, the local variables
1208 space and global environment variables space are
1209 separated. Local variables are those you define by
1210 simply typing `name=value'. To access a local
1211 variable later on, you have write `$name' or
1212 `${name}'; to execute the contents of a variable
1213 directly type `$name' at the command prompt.
1215 Global environment variables are those you use
1216 setenv/printenv to work with. To run a command stored
1217 in such a variable, you need to use the run command,
1218 and you must not use the '$' sign to access them.
1220 To store commands and special characters in a
1221 variable, please use double quotation marks
1222 surrounding the whole text of the variable, instead
1223 of the backslashes before semicolons and special
1226 - Default Environment
1227 CONFIG_EXTRA_ENV_SETTINGS
1229 Define this to contain any number of null terminated
1230 strings (variable = value pairs) that will be part of
1231 the default enviroment compiled into the boot image.
1233 For example, place something like this in your
1234 board's config file:
1236 #define CONFIG_EXTRA_ENV_SETTINGS \
1240 Warning: This method is based on knowledge about the
1241 internal format how the environment is stored by the
1242 U-Boot code. This is NOT an official, exported
1243 interface! Although it is unlikely that this format
1244 will change soon, but there is no guarantee either.
1245 You better know what you are doing here.
1247 Note: overly (ab)use of the default environment is
1248 discouraged. Make sure to check other ways to preset
1249 the environment like the autoscript function or the
1253 CONFIG_HAS_DATAFLASH
1255 Defining this option enables DataFlash features and
1256 allows to read/write in Dataflash via the standard
1259 - Show boot progress
1260 CONFIG_SHOW_BOOT_PROGRESS
1262 Defining this option allows to add some board-
1263 specific code (calling a user-provided function
1264 "show_boot_progress(int)") that enables you to show
1265 the system's boot progress on some display (for
1266 example, some LED's) on your board. At the moment,
1267 the following checkpoints are implemented:
1270 1 common/cmd_bootm.c before attempting to boot an image
1271 -1 common/cmd_bootm.c Image header has bad magic number
1272 2 common/cmd_bootm.c Image header has correct magic number
1273 -2 common/cmd_bootm.c Image header has bad checksum
1274 3 common/cmd_bootm.c Image header has correct checksum
1275 -3 common/cmd_bootm.c Image data has bad checksum
1276 4 common/cmd_bootm.c Image data has correct checksum
1277 -4 common/cmd_bootm.c Image is for unsupported architecture
1278 5 common/cmd_bootm.c Architecture check OK
1279 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1280 6 common/cmd_bootm.c Image Type check OK
1281 -6 common/cmd_bootm.c gunzip uncompression error
1282 -7 common/cmd_bootm.c Unimplemented compression type
1283 7 common/cmd_bootm.c Uncompression OK
1284 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1285 8 common/cmd_bootm.c Image Type check OK
1286 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1287 9 common/cmd_bootm.c Start initial ramdisk verification
1288 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1289 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1290 10 common/cmd_bootm.c Ramdisk header is OK
1291 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1292 11 common/cmd_bootm.c Ramdisk data has correct checksum
1293 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1294 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1295 13 common/cmd_bootm.c Start multifile image verification
1296 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1297 15 common/cmd_bootm.c All preparation done, transferring control to OS
1299 -1 common/cmd_doc.c Bad usage of "doc" command
1300 -1 common/cmd_doc.c No boot device
1301 -1 common/cmd_doc.c Unknown Chip ID on boot device
1302 -1 common/cmd_doc.c Read Error on boot device
1303 -1 common/cmd_doc.c Image header has bad magic number
1305 -1 common/cmd_ide.c Bad usage of "ide" command
1306 -1 common/cmd_ide.c No boot device
1307 -1 common/cmd_ide.c Unknown boot device
1308 -1 common/cmd_ide.c Unknown partition table
1309 -1 common/cmd_ide.c Invalid partition type
1310 -1 common/cmd_ide.c Read Error on boot device
1311 -1 common/cmd_ide.c Image header has bad magic number
1313 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1319 [so far only for SMDK2400 and TRAB boards]
1321 - Modem support endable:
1322 CONFIG_MODEM_SUPPORT
1324 - RTS/CTS Flow control enable:
1327 - Modem debug support:
1328 CONFIG_MODEM_SUPPORT_DEBUG
1330 Enables debugging stuff (char screen[1024], dbg())
1331 for modem support. Useful only with BDI2000.
1335 In the target system modem support is enabled when a
1336 specific key (key combination) is pressed during
1337 power-on. Otherwise U-Boot will boot normally
1338 (autoboot). The key_pressed() fuction is called from
1339 board_init(). Currently key_pressed() is a dummy
1340 function, returning 1 and thus enabling modem
1343 If there are no modem init strings in the
1344 environment, U-Boot proceed to autoboot; the
1345 previous output (banner, info printfs) will be
1348 See also: doc/README.Modem
1353 Configuration Settings:
1354 -----------------------
1356 - CFG_LONGHELP: Defined when you want long help messages included;
1357 undefine this when you're short of memory.
1359 - CFG_PROMPT: This is what U-Boot prints on the console to
1360 prompt for user input.
1362 - CFG_CBSIZE: Buffer size for input from the Console
1364 - CFG_PBSIZE: Buffer size for Console output
1366 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1368 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1369 the application (usually a Linux kernel) when it is
1372 - CFG_BAUDRATE_TABLE:
1373 List of legal baudrate settings for this board.
1375 - CFG_CONSOLE_INFO_QUIET
1376 Suppress display of console information at boot.
1378 - CFG_CONSOLE_IS_IN_ENV
1379 If the board specific function
1380 extern int overwrite_console (void);
1381 returns 1, the stdin, stderr and stdout are switched to the
1382 serial port, else the settings in the environment are used.
1384 - CFG_CONSOLE_OVERWRITE_ROUTINE
1385 Enable the call to overwrite_console().
1387 - CFG_CONSOLE_ENV_OVERWRITE
1388 Enable overwrite of previous console environment settings.
1390 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1391 Begin and End addresses of the area used by the
1395 Enable an alternate, more extensive memory test.
1397 - CFG_TFTP_LOADADDR:
1398 Default load address for network file downloads
1400 - CFG_LOADS_BAUD_CHANGE:
1401 Enable temporary baudrate change while serial download
1404 Physical start address of SDRAM. _Must_ be 0 here.
1407 Physical start address of Motherboard I/O (if using a
1411 Physical start address of Flash memory.
1414 Physical start address of boot monitor code (set by
1415 make config files to be same as the text base address
1416 (TEXT_BASE) used when linking) - same as
1417 CFG_FLASH_BASE when booting from flash.
1420 Size of memory reserved for monitor code, used to
1421 determine _at_compile_time_ (!) if the environment is
1422 embedded within the U-Boot image, or in a separate
1426 Size of DRAM reserved for malloc() use.
1429 Maximum size of memory mapped by the startup code of
1430 the Linux kernel; all data that must be processed by
1431 the Linux kernel (bd_info, boot arguments, eventually
1432 initrd image) must be put below this limit.
1434 - CFG_MAX_FLASH_BANKS:
1435 Max number of Flash memory banks
1437 - CFG_MAX_FLASH_SECT:
1438 Max number of sectors on a Flash chip
1440 - CFG_FLASH_ERASE_TOUT:
1441 Timeout for Flash erase operations (in ms)
1443 - CFG_FLASH_WRITE_TOUT:
1444 Timeout for Flash write operations (in ms)
1446 - CFG_DIRECT_FLASH_TFTP:
1448 Enable TFTP transfers directly to flash memory;
1449 without this option such a download has to be
1450 performed in two steps: (1) download to RAM, and (2)
1451 copy from RAM to flash.
1453 The two-step approach is usually more reliable, since
1454 you can check if the download worked before you erase
1455 the flash, but in some situations (when sytem RAM is
1456 too limited to allow for a tempory copy of the
1457 downloaded image) this option may be very useful.
1460 Define if the flash driver uses extra elements in the
1461 common flash structure for storing flash geometry
1463 - CFG_RX_ETH_BUFFER:
1464 Defines the number of ethernet receive buffers. On some
1465 ethernet controllers it is recommended to set this value
1466 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1467 buffers can be full shortly after enabling the interface
1468 on high ethernet traffic.
1469 Defaults to 4 if not defined.
1471 The following definitions that deal with the placement and management
1472 of environment data (variable area); in general, we support the
1473 following configurations:
1475 - CFG_ENV_IS_IN_FLASH:
1477 Define this if the environment is in flash memory.
1479 a) The environment occupies one whole flash sector, which is
1480 "embedded" in the text segment with the U-Boot code. This
1481 happens usually with "bottom boot sector" or "top boot
1482 sector" type flash chips, which have several smaller
1483 sectors at the start or the end. For instance, such a
1484 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1485 such a case you would place the environment in one of the
1486 4 kB sectors - with U-Boot code before and after it. With
1487 "top boot sector" type flash chips, you would put the
1488 environment in one of the last sectors, leaving a gap
1489 between U-Boot and the environment.
1493 Offset of environment data (variable area) to the
1494 beginning of flash memory; for instance, with bottom boot
1495 type flash chips the second sector can be used: the offset
1496 for this sector is given here.
1498 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1502 This is just another way to specify the start address of
1503 the flash sector containing the environment (instead of
1506 - CFG_ENV_SECT_SIZE:
1508 Size of the sector containing the environment.
1511 b) Sometimes flash chips have few, equal sized, BIG sectors.
1512 In such a case you don't want to spend a whole sector for
1517 If you use this in combination with CFG_ENV_IS_IN_FLASH
1518 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1519 of this flash sector for the environment. This saves
1520 memory for the RAM copy of the environment.
1522 It may also save flash memory if you decide to use this
1523 when your environment is "embedded" within U-Boot code,
1524 since then the remainder of the flash sector could be used
1525 for U-Boot code. It should be pointed out that this is
1526 STRONGLY DISCOURAGED from a robustness point of view:
1527 updating the environment in flash makes it always
1528 necessary to erase the WHOLE sector. If something goes
1529 wrong before the contents has been restored from a copy in
1530 RAM, your target system will be dead.
1532 - CFG_ENV_ADDR_REDUND
1535 These settings describe a second storage area used to hold
1536 a redundand copy of the environment data, so that there is
1537 a valid backup copy in case there is a power failure during
1538 a "saveenv" operation.
1540 BE CAREFUL! Any changes to the flash layout, and some changes to the
1541 source code will make it necessary to adapt <board>/u-boot.lds*
1545 - CFG_ENV_IS_IN_NVRAM:
1547 Define this if you have some non-volatile memory device
1548 (NVRAM, battery buffered SRAM) which you want to use for the
1554 These two #defines are used to determin the memory area you
1555 want to use for environment. It is assumed that this memory
1556 can just be read and written to, without any special
1559 BE CAREFUL! The first access to the environment happens quite early
1560 in U-Boot initalization (when we try to get the setting of for the
1561 console baudrate). You *MUST* have mappend your NVRAM area then, or
1564 Please note that even with NVRAM we still use a copy of the
1565 environment in RAM: we could work on NVRAM directly, but we want to
1566 keep settings there always unmodified except somebody uses "saveenv"
1567 to save the current settings.
1570 - CFG_ENV_IS_IN_EEPROM:
1572 Use this if you have an EEPROM or similar serial access
1573 device and a driver for it.
1578 These two #defines specify the offset and size of the
1579 environment area within the total memory of your EEPROM.
1581 - CFG_I2C_EEPROM_ADDR:
1582 If defined, specified the chip address of the EEPROM device.
1583 The default address is zero.
1585 - CFG_EEPROM_PAGE_WRITE_BITS:
1586 If defined, the number of bits used to address bytes in a
1587 single page in the EEPROM device. A 64 byte page, for example
1588 would require six bits.
1590 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1591 If defined, the number of milliseconds to delay between
1592 page writes. The default is zero milliseconds.
1594 - CFG_I2C_EEPROM_ADDR_LEN:
1595 The length in bytes of the EEPROM memory array address. Note
1596 that this is NOT the chip address length!
1599 The size in bytes of the EEPROM device.
1602 - CFG_SPI_INIT_OFFSET
1604 Defines offset to the initial SPI buffer area in DPRAM. The
1605 area is used at an early stage (ROM part) if the environment
1606 is configured to reside in the SPI EEPROM: We need a 520 byte
1607 scratch DPRAM area. It is used between the two initialization
1608 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1609 to be a good choice since it makes it far enough from the
1610 start of the data area as well as from the stack pointer.
1612 Please note that the environment is read-only as long as the monitor
1613 has been relocated to RAM and a RAM copy of the environment has been
1614 created; also, when using EEPROM you will have to use getenv_r()
1615 until then to read environment variables.
1617 The environment is protected by a CRC32 checksum. Before the monitor
1618 is relocated into RAM, as a result of a bad CRC you will be working
1619 with the compiled-in default environment - *silently*!!! [This is
1620 necessary, because the first environment variable we need is the
1621 "baudrate" setting for the console - if we have a bad CRC, we don't
1622 have any device yet where we could complain.]
1624 Note: once the monitor has been relocated, then it will complain if
1625 the default environment is used; a new CRC is computed as soon as you
1626 use the "saveenv" command to store a valid environment.
1629 Low Level (hardware related) configuration options:
1630 ---------------------------------------------------
1632 - CFG_CACHELINE_SIZE:
1633 Cache Line Size of the CPU.
1636 Default address of the IMMR after system reset.
1637 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1638 to be able to adjust the position of the IMMR
1639 register after a reset.
1641 - Floppy Disk Support:
1642 CFG_FDC_DRIVE_NUMBER
1644 the default drive number (default value 0)
1648 defines the spacing between fdc chipset registers
1653 defines the offset of register from address. It
1654 depends on which part of the data bus is connected to
1655 the fdc chipset. (default value 0)
1657 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1658 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1661 if CFG_FDC_HW_INIT is defined, then the function
1662 fdc_hw_init() is called at the beginning of the FDC
1663 setup. fdc_hw_init() must be provided by the board
1664 source code. It is used to make hardware dependant
1667 - CFG_IMMR: Physical address of the Internal Memory Mapped
1668 Register; DO NOT CHANGE! (11-4)
1669 [MPC8xx systems only]
1671 - CFG_INIT_RAM_ADDR:
1673 Start address of memory area tha can be used for
1674 initial data and stack; please note that this must be
1675 writable memory that is working WITHOUT special
1676 initialization, i. e. you CANNOT use normal RAM which
1677 will become available only after programming the
1678 memory controller and running certain initialization
1681 U-Boot uses the following memory types:
1682 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1683 - MPC824X: data cache
1684 - PPC4xx: data cache
1686 - CFG_GBL_DATA_OFFSET:
1688 Offset of the initial data structure in the memory
1689 area defined by CFG_INIT_RAM_ADDR. Usually
1690 CFG_GBL_DATA_OFFSET is chosen such that the initial
1691 data is located at the end of the available space
1692 (sometimes written as (CFG_INIT_RAM_END -
1693 CFG_INIT_DATA_SIZE), and the initial stack is just
1694 below that area (growing from (CFG_INIT_RAM_ADDR +
1695 CFG_GBL_DATA_OFFSET) downward.
1698 On the MPC824X (or other systems that use the data
1699 cache for initial memory) the address chosen for
1700 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1701 point to an otherwise UNUSED address space between
1702 the top of RAM and the start of the PCI space.
1704 - CFG_SIUMCR: SIU Module Configuration (11-6)
1706 - CFG_SYPCR: System Protection Control (11-9)
1708 - CFG_TBSCR: Time Base Status and Control (11-26)
1710 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1712 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1714 - CFG_SCCR: System Clock and reset Control Register (15-27)
1716 - CFG_OR_TIMING_SDRAM:
1720 periodic timer for refresh
1722 - CFG_DER: Debug Event Register (37-47)
1724 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1725 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1726 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1728 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1730 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1731 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1732 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1733 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1735 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1736 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1737 Machine Mode Register and Memory Periodic Timer
1738 Prescaler definitions (SDRAM timing)
1740 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1741 enable I2C microcode relocation patch (MPC8xx);
1742 define relocation offset in DPRAM [DSP2]
1744 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1745 enable SPI microcode relocation patch (MPC8xx);
1746 define relocation offset in DPRAM [SCC4]
1749 Use OSCM clock mode on MBX8xx board. Be careful,
1750 wrong setting might damage your board. Read
1751 doc/README.MBX before setting this variable!
1753 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1754 Offset of the bootmode word in DPRAM used by post
1755 (Power On Self Tests). This definition overrides
1756 #define'd default value in commproc.h resp.
1759 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1760 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1761 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1762 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1763 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1764 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1765 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1766 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1767 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1769 Building the Software:
1770 ======================
1772 Building U-Boot has been tested in native PPC environments (on a
1773 PowerBook G3 running LinuxPPC 2000) and in cross environments
1774 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1777 If you are not using a native PPC environment, it is assumed that you
1778 have the GNU cross compiling tools available in your path and named
1779 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1780 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1781 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1784 CROSS_COMPILE = ppc_4xx-
1787 U-Boot is intended to be simple to build. After installing the
1788 sources you must configure U-Boot for one specific board type. This
1793 where "NAME_config" is the name of one of the existing
1794 configurations; the following names are supported:
1796 ADCIOP_config GTH_config TQM850L_config
1797 ADS860_config IP860_config TQM855L_config
1798 AR405_config IVML24_config TQM860L_config
1799 CANBT_config IVMS8_config WALNUT405_config
1800 CPCI405_config LANTEC_config cogent_common_config
1801 CPCIISER4_config MBX_config cogent_mpc8260_config
1802 CU824_config MBX860T_config cogent_mpc8xx_config
1803 ESTEEM192E_config RPXlite_config hermes_config
1804 ETX094_config RPXsuper_config hymod_config
1805 FADS823_config SM850_config lwmon_config
1806 FADS850SAR_config SPD823TS_config pcu_e_config
1807 FADS860T_config SXNI855T_config rsdproto_config
1808 FPS850L_config Sandpoint8240_config sbc8260_config
1809 GENIETV_config TQM823L_config PIP405_config
1810 GEN860T_config EBONY_config FPS860L_config
1811 ELPT860_config cmi_mpc5xx_config NETVIA_config
1814 Note: for some board special configuration names may exist; check if
1815 additional information is available from the board vendor; for
1816 instance, the TQM8xxL systems run normally at 50 MHz and use a
1817 SCC for 10baseT ethernet; there are also systems with 80 MHz
1818 CPU clock, and an optional Fast Ethernet module is available
1819 for CPU's with FEC. You can select such additional "features"
1820 when chosing the configuration, i. e.
1823 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1825 make TQM860L_FEC_config
1826 - will configure for a TQM860L at 50MHz with FEC for ethernet
1828 make TQM860L_80MHz_config
1829 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1832 make TQM860L_FEC_80MHz_config
1833 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1835 make TQM823L_LCD_config
1836 - will configure for a TQM823L with U-Boot console on LCD
1838 make TQM823L_LCD_80MHz_config
1839 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1845 Finally, type "make all", and you should get some working U-Boot
1846 images ready for downlod to / installation on your system:
1848 - "u-boot.bin" is a raw binary image
1849 - "u-boot" is an image in ELF binary format
1850 - "u-boot.srec" is in Motorola S-Record format
1853 Please be aware that the Makefiles assume you are using GNU make, so
1854 for instance on NetBSD you might need to use "gmake" instead of
1858 If the system board that you have is not listed, then you will need
1859 to port U-Boot to your hardware platform. To do this, follow these
1862 1. Add a new configuration option for your board to the toplevel
1863 "Makefile" and to the "MAKEALL" script, using the existing
1864 entries as examples. Note that here and at many other places
1865 boards and other names are listed alphabetically sorted. Please
1867 2. Create a new directory to hold your board specific code. Add any
1868 files you need. In your board directory, you will need at least
1869 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1870 3. Create a new configuration file "include/configs/<board>.h" for
1872 3. If you're porting U-Boot to a new CPU, then also create a new
1873 directory to hold your CPU specific code. Add any files you need.
1874 4. Run "make <board>_config" with your new name.
1875 5. Type "make", and you should get a working "u-boot.srec" file
1876 to be installed on your target system.
1877 6. Debug and solve any problems that might arise.
1878 [Of course, this last step is much harder than it sounds.]
1881 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1882 ==============================================================
1884 If you have modified U-Boot sources (for instance added a new board
1885 or support for new devices, a new CPU, etc.) you are expected to
1886 provide feedback to the other developers. The feedback normally takes
1887 the form of a "patch", i. e. a context diff against a certain (latest
1888 official or latest in CVS) version of U-Boot sources.
1890 But before you submit such a patch, please verify that your modifi-
1891 cation did not break existing code. At least make sure that *ALL* of
1892 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1893 just run the "MAKEALL" script, which will configure and build U-Boot
1894 for ALL supported system. Be warned, this will take a while. You can
1895 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1896 environment variable to the script, i. e. to use the cross tools from
1897 MontaVista's Hard Hat Linux you can type
1899 CROSS_COMPILE=ppc_8xx- MAKEALL
1901 or to build on a native PowerPC system you can type
1903 CROSS_COMPILE=' ' MAKEALL
1905 See also "U-Boot Porting Guide" below.
1909 Monitor Commands - Overview:
1910 ============================
1912 go - start application at address 'addr'
1913 run - run commands in an environment variable
1914 bootm - boot application image from memory
1915 bootp - boot image via network using BootP/TFTP protocol
1916 tftpboot- boot image via network using TFTP protocol
1917 and env variables "ipaddr" and "serverip"
1918 (and eventually "gatewayip")
1919 rarpboot- boot image via network using RARP/TFTP protocol
1920 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1921 loads - load S-Record file over serial line
1922 loadb - load binary file over serial line (kermit mode)
1924 mm - memory modify (auto-incrementing)
1925 nm - memory modify (constant address)
1926 mw - memory write (fill)
1928 cmp - memory compare
1929 crc32 - checksum calculation
1930 imd - i2c memory display
1931 imm - i2c memory modify (auto-incrementing)
1932 inm - i2c memory modify (constant address)
1933 imw - i2c memory write (fill)
1934 icrc32 - i2c checksum calculation
1935 iprobe - probe to discover valid I2C chip addresses
1936 iloop - infinite loop on address range
1937 isdram - print SDRAM configuration information
1938 sspi - SPI utility commands
1939 base - print or set address offset
1940 printenv- print environment variables
1941 setenv - set environment variables
1942 saveenv - save environment variables to persistent storage
1943 protect - enable or disable FLASH write protection
1944 erase - erase FLASH memory
1945 flinfo - print FLASH memory information
1946 bdinfo - print Board Info structure
1947 iminfo - print header information for application image
1948 coninfo - print console devices and informations
1949 ide - IDE sub-system
1950 loop - infinite loop on address range
1951 mtest - simple RAM test
1952 icache - enable or disable instruction cache
1953 dcache - enable or disable data cache
1954 reset - Perform RESET of the CPU
1955 echo - echo args to console
1956 version - print monitor version
1957 help - print online help
1958 ? - alias for 'help'
1961 Monitor Commands - Detailed Description:
1962 ========================================
1966 For now: just type "help <command>".
1969 Environment Variables:
1970 ======================
1972 U-Boot supports user configuration using Environment Variables which
1973 can be made persistent by saving to Flash memory.
1975 Environment Variables are set using "setenv", printed using
1976 "printenv", and saved to Flash using "saveenv". Using "setenv"
1977 without a value can be used to delete a variable from the
1978 environment. As long as you don't save the environment you are
1979 working with an in-memory copy. In case the Flash area containing the
1980 environment is erased by accident, a default environment is provided.
1982 Some configuration options can be set using Environment Variables:
1984 baudrate - see CONFIG_BAUDRATE
1986 bootdelay - see CONFIG_BOOTDELAY
1988 bootcmd - see CONFIG_BOOTCOMMAND
1990 bootargs - Boot arguments when booting an RTOS image
1992 bootfile - Name of the image to load with TFTP
1994 autoload - if set to "no" (any string beginning with 'n'),
1995 "bootp" will just load perform a lookup of the
1996 configuration from the BOOTP server, but not try to
1997 load any image using TFTP
1999 autostart - if set to "yes", an image loaded using the "bootp",
2000 "rarpboot", "tftpboot" or "diskboot" commands will
2001 be automatically started (by internally calling
2004 If set to "no", a standalone image passed to the
2005 "bootm" command will be copied to the load address
2006 (and eventually uncompressed), but NOT be started.
2007 This can be used to load and uncompress arbitrary
2010 initrd_high - restrict positioning of initrd images:
2011 If this variable is not set, initrd images will be
2012 copied to the highest possible address in RAM; this
2013 is usually what you want since it allows for
2014 maximum initrd size. If for some reason you want to
2015 make sure that the initrd image is loaded below the
2016 CFG_BOOTMAPSZ limit, you can set this environment
2017 variable to a value of "no" or "off" or "0".
2018 Alternatively, you can set it to a maximum upper
2019 address to use (U-Boot will still check that it
2020 does not overwrite the U-Boot stack and data).
2022 For instance, when you have a system with 16 MB
2023 RAM, and want to reseve 4 MB from use by Linux,
2024 you can do this by adding "mem=12M" to the value of
2025 the "bootargs" variable. However, now you must make
2026 sure, that the initrd image is placed in the first
2027 12 MB as well - this can be done with
2029 setenv initrd_high 00c00000
2031 If you set initrd_high to 0xFFFFFFFF, this is an
2032 indication to U-Boot that all addresses are legal
2033 for the Linux kernel, including addresses in flash
2034 memory. In this case U-Boot will NOT COPY the
2035 ramdisk at all. This may be useful to reduce the
2036 boot time on your system, but requires that this
2037 feature is supported by your Linux kernel.
2039 ipaddr - IP address; needed for tftpboot command
2041 loadaddr - Default load address for commands like "bootp",
2042 "rarpboot", "tftpboot", "loadb" or "diskboot"
2044 loads_echo - see CONFIG_LOADS_ECHO
2046 serverip - TFTP server IP address; needed for tftpboot command
2048 bootretry - see CONFIG_BOOT_RETRY_TIME
2050 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2052 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2055 The following environment variables may be used and automatically
2056 updated by the network boot commands ("bootp" and "rarpboot"),
2057 depending the information provided by your boot server:
2059 bootfile - see above
2060 dnsip - IP address of your Domain Name Server
2061 gatewayip - IP address of the Gateway (Router) to use
2062 hostname - Target hostname
2064 netmask - Subnet Mask
2065 rootpath - Pathname of the root filesystem on the NFS server
2066 serverip - see above
2069 There are two special Environment Variables:
2071 serial# - contains hardware identification information such
2072 as type string and/or serial number
2073 ethaddr - Ethernet address
2075 These variables can be set only once (usually during manufacturing of
2076 the board). U-Boot refuses to delete or overwrite these variables
2077 once they have been set once.
2080 Further special Environment Variables:
2082 ver - Contains the U-Boot version string as printed
2083 with the "version" command. This variable is
2084 readonly (see CONFIG_VERSION_VARIABLE).
2087 Please note that changes to some configuration parameters may take
2088 only effect after the next boot (yes, that's just like Windoze :-).
2091 Command Line Parsing:
2092 =====================
2094 There are two different command line parsers available with U-Boot:
2095 the old "simple" one, and the much more pwerful "hush" shell:
2097 Old, simple command line parser:
2098 --------------------------------
2100 - supports environment variables (through setenv / saveenv commands)
2101 - several commands on one line, separated by ';'
2102 - variable substitution using "... $(name) ..." syntax
2103 - special characters ('$', ';') can be escaped by prefixing with '\',
2105 setenv bootcmd bootm \$(address)
2106 - You can also escape text by enclosing in single apostrophes, for example:
2107 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2112 - similar to Bourne shell, with control structures like
2113 if...then...else...fi, for...do...done; while...do...done,
2114 until...do...done, ...
2115 - supports environment ("global") variables (through setenv / saveenv
2116 commands) and local shell variables (through standard shell syntax
2117 "name=value"); only environment variables can be used with "run"
2123 (1) If a command line (or an environment variable executed by a "run"
2124 command) contains several commands separated by semicolon, and
2125 one of these commands fails, then the remaining commands will be
2128 (2) If you execute several variables with one call to run (i. e.
2129 calling run with a list af variables as arguments), any failing
2130 command will cause "run" to terminate, i. e. the remaining
2131 variables are not executed.
2133 Note for Redundant Ethernet Interfaces:
2134 =======================================
2136 Some boards come with redundand ethernet interfaces; U-Boot supports
2137 such configurations and is capable of automatic selection of a
2138 "working" interface when needed. MAC assignemnt works as follows:
2140 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2141 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2142 "eth1addr" (=>eth1), "eth2addr", ...
2144 If the network interface stores some valid MAC address (for instance
2145 in SROM), this is used as default address if there is NO correspon-
2146 ding setting in the environment; if the corresponding environment
2147 variable is set, this overrides the settings in the card; that means:
2149 o If the SROM has a valid MAC address, and there is no address in the
2150 environment, the SROM's address is used.
2152 o If there is no valid address in the SROM, and a definition in the
2153 environment exists, then the value from the environment variable is
2156 o If both the SROM and the environment contain a MAC address, and
2157 both addresses are the same, this MAC address is used.
2159 o If both the SROM and the environment contain a MAC address, and the
2160 addresses differ, the value from the environment is used and a
2163 o If neither SROM nor the environment contain a MAC address, an error
2171 The "boot" commands of this monitor operate on "image" files which
2172 can be basicly anything, preceeded by a special header; see the
2173 definitions in include/image.h for details; basicly, the header
2174 defines the following image properties:
2176 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2177 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2178 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2179 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS).
2180 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2181 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2182 Currently supported: PowerPC).
2183 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2184 Currently supported: uncompressed, gzip).
2190 The header is marked by a special Magic Number, and both the header
2191 and the data portions of the image are secured against corruption by
2198 Although U-Boot should support any OS or standalone application
2199 easily, Linux has always been in the focus during the design of
2202 U-Boot includes many features that so far have been part of some
2203 special "boot loader" code within the Linux kernel. Also, any
2204 "initrd" images to be used are no longer part of one big Linux image;
2205 instead, kernel and "initrd" are separate images. This implementation
2206 serves serveral purposes:
2208 - the same features can be used for other OS or standalone
2209 applications (for instance: using compressed images to reduce the
2210 Flash memory footprint)
2212 - it becomes much easier to port new Linux kernel versions because
2213 lots of low-level, hardware dependend stuff are done by U-Boot
2215 - the same Linux kernel image can now be used with different "initrd"
2216 images; of course this also means that different kernel images can
2217 be run with the same "initrd". This makes testing easier (you don't
2218 have to build a new "zImage.initrd" Linux image when you just
2219 change a file in your "initrd"). Also, a field-upgrade of the
2220 software is easier now.
2226 Porting Linux to U-Boot based systems:
2227 ---------------------------------------
2229 U-Boot cannot save you from doing all the necessary modifications to
2230 configure the Linux device drivers for use with your target hardware
2231 (no, we don't intend to provide a full virtual machine interface to
2234 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2236 Just make sure your machine specific header file (for instance
2237 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2238 Information structure as we define in include/u-boot.h, and make
2239 sure that your definition of IMAP_ADDR uses the same value as your
2240 U-Boot configuration in CFG_IMMR.
2243 Configuring the Linux kernel:
2244 -----------------------------
2246 No specific requirements for U-Boot. Make sure you have some root
2247 device (initial ramdisk, NFS) for your target system.
2250 Building a Linux Image:
2251 -----------------------
2253 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2254 not used. If you use recent kernel source, a new build target
2255 "uImage" will exist which automatically builds an image usable by
2256 U-Boot. Most older kernels also have support for a "pImage" target,
2257 which was introduced for our predecessor project PPCBoot and uses a
2258 100% compatible format.
2267 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2268 encapsulate a compressed Linux kernel image with header information,
2269 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2271 * build a standard "vmlinux" kernel image (in ELF binary format):
2273 * convert the kernel into a raw binary image:
2275 ${CROSS_COMPILE}-objcopy -O binary \
2276 -R .note -R .comment \
2277 -S vmlinux linux.bin
2279 * compress the binary image:
2283 * package compressed binary image for U-Boot:
2285 mkimage -A ppc -O linux -T kernel -C gzip \
2286 -a 0 -e 0 -n "Linux Kernel Image" \
2287 -d linux.bin.gz uImage
2290 The "mkimage" tool can also be used to create ramdisk images for use
2291 with U-Boot, either separated from the Linux kernel image, or
2292 combined into one file. "mkimage" encapsulates the images with a 64
2293 byte header containing information about target architecture,
2294 operating system, image type, compression method, entry points, time
2295 stamp, CRC32 checksums, etc.
2297 "mkimage" can be called in two ways: to verify existing images and
2298 print the header information, or to build new images.
2300 In the first form (with "-l" option) mkimage lists the information
2301 contained in the header of an existing U-Boot image; this includes
2302 checksum verification:
2304 tools/mkimage -l image
2305 -l ==> list image header information
2307 The second form (with "-d" option) is used to build a U-Boot image
2308 from a "data file" which is used as image payload:
2310 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2311 -n name -d data_file image
2312 -A ==> set architecture to 'arch'
2313 -O ==> set operating system to 'os'
2314 -T ==> set image type to 'type'
2315 -C ==> set compression type 'comp'
2316 -a ==> set load address to 'addr' (hex)
2317 -e ==> set entry point to 'ep' (hex)
2318 -n ==> set image name to 'name'
2319 -d ==> use image data from 'datafile'
2321 Right now, all Linux kernels use the same load address (0x00000000),
2322 but the entry point address depends on the kernel version:
2324 - 2.2.x kernels have the entry point at 0x0000000C,
2325 - 2.3.x and later kernels have the entry point at 0x00000000.
2327 So a typical call to build a U-Boot image would read:
2329 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2330 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2331 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2332 > examples/uImage.TQM850L
2333 Image Name: 2.4.4 kernel for TQM850L
2334 Created: Wed Jul 19 02:34:59 2000
2335 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2336 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2337 Load Address: 0x00000000
2338 Entry Point: 0x00000000
2340 To verify the contents of the image (or check for corruption):
2342 -> tools/mkimage -l examples/uImage.TQM850L
2343 Image Name: 2.4.4 kernel for TQM850L
2344 Created: Wed Jul 19 02:34:59 2000
2345 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2346 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2347 Load Address: 0x00000000
2348 Entry Point: 0x00000000
2350 NOTE: for embedded systems where boot time is critical you can trade
2351 speed for memory and install an UNCOMPRESSED image instead: this
2352 needs more space in Flash, but boots much faster since it does not
2353 need to be uncompressed:
2355 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2356 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2357 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2358 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2359 > examples/uImage.TQM850L-uncompressed
2360 Image Name: 2.4.4 kernel for TQM850L
2361 Created: Wed Jul 19 02:34:59 2000
2362 Image Type: PowerPC Linux Kernel Image (uncompressed)
2363 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2364 Load Address: 0x00000000
2365 Entry Point: 0x00000000
2368 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2369 when your kernel is intended to use an initial ramdisk:
2371 -> tools/mkimage -n 'Simple Ramdisk Image' \
2372 > -A ppc -O linux -T ramdisk -C gzip \
2373 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2374 Image Name: Simple Ramdisk Image
2375 Created: Wed Jan 12 14:01:50 2000
2376 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2377 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2378 Load Address: 0x00000000
2379 Entry Point: 0x00000000
2382 Installing a Linux Image:
2383 -------------------------
2385 To downloading a U-Boot image over the serial (console) interface,
2386 you must convert the image to S-Record format:
2388 objcopy -I binary -O srec examples/image examples/image.srec
2390 The 'objcopy' does not understand the information in the U-Boot
2391 image header, so the resulting S-Record file will be relative to
2392 address 0x00000000. To load it to a given address, you need to
2393 specify the target address as 'offset' parameter with the 'loads'
2396 Example: install the image to address 0x40100000 (which on the
2397 TQM8xxL is in the first Flash bank):
2399 => erase 40100000 401FFFFF
2405 ## Ready for S-Record download ...
2406 ~>examples/image.srec
2407 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2409 15989 15990 15991 15992
2410 [file transfer complete]
2412 ## Start Addr = 0x00000000
2415 You can check the success of the download using the 'iminfo' command;
2416 this includes a checksum verification so you can be sure no data
2417 corruption happened:
2421 ## Checking Image at 40100000 ...
2422 Image Name: 2.2.13 for initrd on TQM850L
2423 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2424 Data Size: 335725 Bytes = 327 kB = 0 MB
2425 Load Address: 00000000
2426 Entry Point: 0000000c
2427 Verifying Checksum ... OK
2434 The "bootm" command is used to boot an application that is stored in
2435 memory (RAM or Flash). In case of a Linux kernel image, the contents
2436 of the "bootargs" environment variable is passed to the kernel as
2437 parameters. You can check and modify this variable using the
2438 "printenv" and "setenv" commands:
2441 => printenv bootargs
2442 bootargs=root=/dev/ram
2444 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2446 => printenv bootargs
2447 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2450 ## Booting Linux kernel at 40020000 ...
2451 Image Name: 2.2.13 for NFS on TQM850L
2452 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2453 Data Size: 381681 Bytes = 372 kB = 0 MB
2454 Load Address: 00000000
2455 Entry Point: 0000000c
2456 Verifying Checksum ... OK
2457 Uncompressing Kernel Image ... OK
2458 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
2459 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2460 time_init: decrementer frequency = 187500000/60
2461 Calibrating delay loop... 49.77 BogoMIPS
2462 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2465 If you want to boot a Linux kernel with initial ram disk, you pass
2466 the memory addreses of both the kernel and the initrd image (PPBCOOT
2467 format!) to the "bootm" command:
2469 => imi 40100000 40200000
2471 ## Checking Image at 40100000 ...
2472 Image Name: 2.2.13 for initrd on TQM850L
2473 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2474 Data Size: 335725 Bytes = 327 kB = 0 MB
2475 Load Address: 00000000
2476 Entry Point: 0000000c
2477 Verifying Checksum ... OK
2479 ## Checking Image at 40200000 ...
2480 Image Name: Simple Ramdisk Image
2481 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2482 Data Size: 566530 Bytes = 553 kB = 0 MB
2483 Load Address: 00000000
2484 Entry Point: 00000000
2485 Verifying Checksum ... OK
2487 => bootm 40100000 40200000
2488 ## Booting Linux kernel at 40100000 ...
2489 Image Name: 2.2.13 for initrd on TQM850L
2490 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2491 Data Size: 335725 Bytes = 327 kB = 0 MB
2492 Load Address: 00000000
2493 Entry Point: 0000000c
2494 Verifying Checksum ... OK
2495 Uncompressing Kernel Image ... OK
2496 ## Loading RAMDisk Image at 40200000 ...
2497 Image Name: Simple Ramdisk Image
2498 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2499 Data Size: 566530 Bytes = 553 kB = 0 MB
2500 Load Address: 00000000
2501 Entry Point: 00000000
2502 Verifying Checksum ... OK
2503 Loading Ramdisk ... OK
2504 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
2505 Boot arguments: root=/dev/ram
2506 time_init: decrementer frequency = 187500000/60
2507 Calibrating delay loop... 49.77 BogoMIPS
2509 RAMDISK: Compressed image found at block 0
2510 VFS: Mounted root (ext2 filesystem).
2514 More About U-Boot Image Types:
2515 ------------------------------
2517 U-Boot supports the following image types:
2519 "Standalone Programs" are directly runnable in the environment
2520 provided by U-Boot; it is expected that (if they behave
2521 well) you can continue to work in U-Boot after return from
2522 the Standalone Program.
2523 "OS Kernel Images" are usually images of some Embedded OS which
2524 will take over control completely. Usually these programs
2525 will install their own set of exception handlers, device
2526 drivers, set up the MMU, etc. - this means, that you cannot
2527 expect to re-enter U-Boot except by resetting the CPU.
2528 "RAMDisk Images" are more or less just data blocks, and their
2529 parameters (address, size) are passed to an OS kernel that is
2531 "Multi-File Images" contain several images, typically an OS
2532 (Linux) kernel image and one or more data images like
2533 RAMDisks. This construct is useful for instance when you want
2534 to boot over the network using BOOTP etc., where the boot
2535 server provides just a single image file, but you want to get
2536 for instance an OS kernel and a RAMDisk image.
2538 "Multi-File Images" start with a list of image sizes, each
2539 image size (in bytes) specified by an "uint32_t" in network
2540 byte order. This list is terminated by an "(uint32_t)0".
2541 Immediately after the terminating 0 follow the images, one by
2542 one, all aligned on "uint32_t" boundaries (size rounded up to
2543 a multiple of 4 bytes).
2545 "Firmware Images" are binary images containing firmware (like
2546 U-Boot or FPGA images) which usually will be programmed to
2549 "Script files" are command sequences that will be executed by
2550 U-Boot's command interpreter; this feature is especially
2551 useful when you configure U-Boot to use a real shell (hush)
2552 as command interpreter.
2558 One of the features of U-Boot is that you can dynamically load and
2559 run "standalone" applications, which can use some resources of
2560 U-Boot like console I/O functions or interrupt services.
2562 Two simple examples are included with the sources:
2567 'examples/hello_world.c' contains a small "Hello World" Demo
2568 application; it is automatically compiled when you build U-Boot.
2569 It's configured to run at address 0x00040004, so you can play with it
2573 ## Ready for S-Record download ...
2574 ~>examples/hello_world.srec
2575 1 2 3 4 5 6 7 8 9 10 11 ...
2576 [file transfer complete]
2578 ## Start Addr = 0x00040004
2580 => go 40004 Hello World! This is a test.
2581 ## Starting application at 0x00040004 ...
2592 Hit any key to exit ...
2594 ## Application terminated, rc = 0x0
2596 Another example, which demonstrates how to register a CPM interrupt
2597 handler with the U-Boot code, can be found in 'examples/timer.c'.
2598 Here, a CPM timer is set up to generate an interrupt every second.
2599 The interrupt service routine is trivial, just printing a '.'
2600 character, but this is just a demo program. The application can be
2601 controlled by the following keys:
2603 ? - print current values og the CPM Timer registers
2604 b - enable interrupts and start timer
2605 e - stop timer and disable interrupts
2606 q - quit application
2609 ## Ready for S-Record download ...
2610 ~>examples/timer.srec
2611 1 2 3 4 5 6 7 8 9 10 11 ...
2612 [file transfer complete]
2614 ## Start Addr = 0x00040004
2617 ## Starting application at 0x00040004 ...
2620 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2623 [q, b, e, ?] Set interval 1000000 us
2626 [q, b, e, ?] ........
2627 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2630 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2633 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2636 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2638 [q, b, e, ?] ...Stopping timer
2640 [q, b, e, ?] ## Application terminated, rc = 0x0
2647 Over time, many people have reported problems when trying to used the
2648 "minicom" terminal emulation program for serial download. I (wd)
2649 consider minicom to be broken, and recommend not to use it. Under
2650 Unix, I recommend to use C-Kermit for general purpose use (and
2651 especially for kermit binary protocol download ("loadb" command), and
2652 use "cu" for S-Record download ("loads" command).
2657 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2658 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2660 Building requires a cross environment; it is known to work on
2661 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2662 need gmake since the Makefiles are not compatible with BSD make).
2663 Note that the cross-powerpc package does not install include files;
2664 attempting to build U-Boot will fail because <machine/ansi.h> is
2665 missing. This file has to be installed and patched manually:
2667 # cd /usr/pkg/cross/powerpc-netbsd/include
2669 # ln -s powerpc machine
2670 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2671 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2673 Native builds *don't* work due to incompatibilities between native
2674 and U-Boot include files.
2676 Booting assumes that (the first part of) the image booted is a
2677 stage-2 loader which in turn loads and then invokes the kernel
2678 proper. Loader sources will eventually appear in the NetBSD source
2679 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2684 Implementation Internals:
2685 =========================
2687 The following is not intended to be a complete description of every
2688 implementation detail. However, it should help to understand the
2689 inner workings of U-Boot and make it easier to port it to custom
2693 Initial Stack, Global Data:
2694 ---------------------------
2696 The implementation of U-Boot is complicated by the fact that U-Boot
2697 starts running out of ROM (flash memory), usually without access to
2698 system RAM (because the memory controller is not initialized yet).
2699 This means that we don't have writable Data or BSS segments, and BSS
2700 is not initialized as zero. To be able to get a C environment working
2701 at all, we have to allocate at least a minimal stack. Implementation
2702 options for this are defined and restricted by the CPU used: Some CPU
2703 models provide on-chip memory (like the IMMR area on MPC8xx and
2704 MPC826x processors), on others (parts of) the data cache can be
2705 locked as (mis-) used as memory, etc.
2707 Chris Hallinan posted a good summy of these issues to the
2708 u-boot-users mailing list:
2710 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2712 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2715 Correct me if I'm wrong, folks, but the way I understand it
2716 is this: Using DCACHE as initial RAM for Stack, etc, does not
2717 require any physical RAM backing up the cache. The cleverness
2718 is that the cache is being used as a temporary supply of
2719 necessary storage before the SDRAM controller is setup. It's
2720 beyond the scope of this list to expain the details, but you
2721 can see how this works by studying the cache architecture and
2722 operation in the architecture and processor-specific manuals.
2724 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2725 is another option for the system designer to use as an
2726 initial stack/ram area prior to SDRAM being available. Either
2727 option should work for you. Using CS 4 should be fine if your
2728 board designers haven't used it for something that would
2729 cause you grief during the initial boot! It is frequently not
2732 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2733 with your processor/board/system design. The default value
2734 you will find in any recent u-boot distribution in
2735 Walnut405.h should work for you. I'd set it to a value larger
2736 than your SDRAM module. If you have a 64MB SDRAM module, set
2737 it above 400_0000. Just make sure your board has no resources
2738 that are supposed to respond to that address! That code in
2739 start.S has been around a while and should work as is when
2740 you get the config right.
2745 It is essential to remember this, since it has some impact on the C
2746 code for the initialization procedures:
2748 * Initialized global data (data segment) is read-only. Do not attempt
2751 * Do not use any unitialized global data (or implicitely initialized
2752 as zero data - BSS segment) at all - this is undefined, initiali-
2753 zation is performed later (when relocationg to RAM).
2755 * Stack space is very limited. Avoid big data buffers or things like
2758 Having only the stack as writable memory limits means we cannot use
2759 normal global data to share information beween the code. But it
2760 turned out that the implementation of U-Boot can be greatly
2761 simplified by making a global data structure (gd_t) available to all
2762 functions. We could pass a pointer to this data as argument to _all_
2763 functions, but this would bloat the code. Instead we use a feature of
2764 the GCC compiler (Global Register Variables) to share the data: we
2765 place a pointer (gd) to the global data into a register which we
2766 reserve for this purpose.
2768 When chosing a register for such a purpose we are restricted by the
2769 relevant (E)ABI specifications for the current architecture, and by
2770 GCC's implementation.
2772 For PowerPC, the following registers have specific use:
2775 R3-R4: parameter passing and return values
2776 R5-R10: parameter passing
2777 R13: small data area pointer
2781 (U-Boot also uses R14 as internal GOT pointer.)
2783 ==> U-Boot will use R29 to hold a pointer to the global data
2785 Note: on PPC, we could use a static initializer (since the
2786 address of the global data structure is known at compile time),
2787 but it turned out that reserving a register results in somewhat
2788 smaller code - although the code savings are not that big (on
2789 average for all boards 752 bytes for the whole U-Boot image,
2790 624 text + 127 data).
2792 On ARM, the following registers are used:
2794 R0: function argument word/integer result
2795 R1-R3: function argument word
2797 R10: stack limit (used only if stack checking if enabled)
2798 R11: argument (frame) pointer
2799 R12: temporary workspace
2802 R15: program counter
2804 ==> U-Boot will use R8 to hold a pointer to the global data
2811 U-Boot runs in system state and uses physical addresses, i.e. the
2812 MMU is not used either for address mapping nor for memory protection.
2814 The available memory is mapped to fixed addresses using the memory
2815 controller. In this process, a contiguous block is formed for each
2816 memory type (Flash, SDRAM, SRAM), even when it consists of several
2817 physical memory banks.
2819 U-Boot is installed in the first 128 kB of the first Flash bank (on
2820 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2821 booting and sizing and initializing DRAM, the code relocates itself
2822 to the upper end of DRAM. Immediately below the U-Boot code some
2823 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2824 configuration setting]. Below that, a structure with global Board
2825 Info data is placed, followed by the stack (growing downward).
2827 Additionally, some exception handler code is copied to the low 8 kB
2828 of DRAM (0x00000000 ... 0x00001FFF).
2830 So a typical memory configuration with 16 MB of DRAM could look like
2833 0x0000 0000 Exception Vector code
2836 0x0000 2000 Free for Application Use
2842 0x00FB FF20 Monitor Stack (Growing downward)
2843 0x00FB FFAC Board Info Data and permanent copy of global data
2844 0x00FC 0000 Malloc Arena
2847 0x00FE 0000 RAM Copy of Monitor Code
2848 ... eventually: LCD or video framebuffer
2849 ... eventually: pRAM (Protected RAM - unchanged by reset)
2850 0x00FF FFFF [End of RAM]
2853 System Initialization:
2854 ----------------------
2856 In the reset configuration, U-Boot starts at the reset entry point
2857 (on most PowerPC systens at address 0x00000100). Because of the reset
2858 configuration for CS0# this is a mirror of the onboard Flash memory.
2859 To be able to re-map memory U-Boot then jumps to it's link address.
2860 To be able to implement the initialization code in C, a (small!)
2861 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2862 which provide such a feature like MPC8xx or MPC8260), or in a locked
2863 part of the data cache. After that, U-Boot initializes the CPU core,
2864 the caches and the SIU.
2866 Next, all (potentially) available memory banks are mapped using a
2867 preliminary mapping. For example, we put them on 512 MB boundaries
2868 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2869 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2870 programmed for SDRAM access. Using the temporary configuration, a
2871 simple memory test is run that determines the size of the SDRAM
2874 When there is more than one SDRAM bank, and the banks are of
2875 different size, the larger is mapped first. For equal size, the first
2876 bank (CS2#) is mapped first. The first mapping is always for address
2877 0x00000000, with any additional banks following immediately to create
2878 contiguous memory starting from 0.
2880 Then, the monitor installs itself at the upper end of the SDRAM area
2881 and allocates memory for use by malloc() and for the global Board
2882 Info data; also, the exception vector code is copied to the low RAM
2883 pages, and the final stack is set up.
2885 Only after this relocation will you have a "normal" C environment;
2886 until that you are restricted in several ways, mostly because you are
2887 running from ROM, and because the code will have to be relocated to a
2891 U-Boot Porting Guide:
2892 ----------------------
2894 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2898 int main (int argc, char *argv[])
2900 sighandler_t no_more_time;
2902 signal (SIGALRM, no_more_time);
2903 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2905 if (available_money > available_manpower) {
2906 pay consultant to port U-Boot;
2910 Download latest U-Boot source;
2912 Subscribe to u-boot-users mailing list;
2915 email ("Hi, I am new to U-Boot, how do I get started?");
2919 Read the README file in the top level directory;
2920 Read http://www.denx.de/re/DPLG.html
2921 Read the source, Luke;
2924 if (available_money > toLocalCurrency ($2500)) {
2927 Add a lot of aggravation and time;
2930 Create your own board support subdirectory;
2932 Create your own board config file;
2936 Add / modify source code;
2940 email ("Hi, I am having problems...");
2942 Send patch file to Wolfgang;
2947 void no_more_time (int sig)
2957 All contributions to U-Boot should conform to the Linux kernel
2958 coding style; see the file "Documentation/CodingStyle" in your Linux
2959 kernel source directory.
2961 Please note that U-Boot is implemented in C (and to some small parts
2962 in Assembler); no C++ is used, so please do not use C++ style
2963 comments (//) in your code.
2965 Submissions which do not conform to the standards may be returned
2966 with a request to reformat the changes.
2972 Since the number of patches for U-Boot is growing, we need to
2973 establish some rules. Submissions which do not conform to these rules
2974 may be rejected, even when they contain important and valuable stuff.
2977 When you send a patch, please include the following information with
2980 * For bug fixes: a description of the bug and how your patch fixes
2981 this bug. Please try to include a way of demonstrating that the
2982 patch actually fixes something.
2984 * For new features: a description of the feature and your
2987 * A CHANGELOG entry as plaintext (separate from the patch)
2989 * For major contributions, your entry to the CREDITS file
2991 * When you add support for a new board, don't forget to add this
2992 board to the MAKEALL script, too.
2994 * If your patch adds new configuration options, don't forget to
2995 document these in the README file.
2997 * The patch itself. If you are accessing the CVS repository use "cvs
2998 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2999 version of diff does not support these options, then get the latest
3000 version of GNU diff.
3002 We accept patches as plain text, MIME attachments or as uuencoded
3007 * Before sending the patch, run the MAKEALL script on your patched
3008 source tree and make sure that no errors or warnings are reported
3009 for any of the boards.
3011 * Keep your modifications to the necessary minimum: A patch
3012 containing several unrelated changes or arbitrary reformats will be
3013 returned with a request to re-formatting / split it.
3015 * If you modify existing code, make sure that your new code does not
3016 add to the memory footprint of the code ;-) Small is beautiful!
3017 When adding new features, these should compile conditionally only
3018 (using #ifdef), and the resulting code with the new feature
3019 disabled must not need more memory than the old code without your
projects / J-u-boot.git / blob