2 # (C) Copyright 2000 - 2002
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC and ARM processors, which can be
29 installed in a boot ROM and used to initialize and test the hardware
30 or to download and run application code.
32 The development of U-Boot is closely related to Linux: some parts of
33 the source code originate in the Linux source tree, we have some
34 header files in common, and special provision has been made to
35 support booting of Linux images.
37 Some attention has been paid to make this software easily
38 configurable and extendable. For instance, all monitor commands are
39 implemented with the same call interface, so that it's very easy to
40 add new commands. Also, instead of permanently adding rarely used
41 code (for instance hardware test utilities) to the monitor, you can
42 load and run it dynamically.
48 In general, all boards for which a configuration option exists in the
49 Makefile have been tested to some extent and can be considered
50 "working". In fact, many of them are used in production systems.
52 In case of problems see the CHANGELOG and CREDITS files to find out
53 who contributed the specific port.
59 In case you have questions about, problems with or contributions for
60 U-Boot you should send a message to the U-Boot mailing list at
61 <u-boot-users@lists.sourceforge.net>. There is also an archive of
62 previous traffic on the mailing list - please search the archive
63 before asking FAQ's. Please see
64 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
70 - start from 8xxrom sources
71 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
73 - make it easier to add custom boards
74 - make it possible to add other [PowerPC] CPUs
75 - extend functions, especially:
76 * Provide extended interface to Linux boot loader
79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80 - create ARMBoot project (http://sourceforge.net/projects/armboot)
81 - add other CPU families (starting with ARM)
82 - create U-Boot project (http://sourceforge.net/projects/u-boot)
88 The "official" name of this project is "Das U-Boot". The spelling
89 "U-Boot" shall be used in all written text (documentation, comments
90 in source files etc.). Example:
92 This is the README file for the U-Boot project.
94 File names etc. shall be based on the string "u-boot". Examples:
96 include/asm-ppc/u-boot.h
98 #include <asm/u-boot.h>
100 Variable names, preprocessor constants etc. shall be either based on
101 the string "u_boot" or on "U_BOOT". Example:
103 U_BOOT_VERSION u_boot_logo
104 IH_OS_U_BOOT u_boot_hush_start
110 U-Boot uses a 3 level version number containing a version, a
111 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112 sub-version "34", and patchlevel "4".
114 The patchlevel is used to indicate certain stages of development
115 between released versions, i. e. officially released versions of
116 U-Boot will always have a patchlevel of "0".
122 - board Board dependend files
123 - common Misc architecture independend functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Common used device drivers
128 - dtt Digital Thermometer and Thermostat drivers
129 - examples Example code for standalone applications, etc.
130 - include Header Files
131 - disk Harddisk interface code
132 - net Networking code
133 - ppc Files generic to PowerPC architecture
134 - post Power On Self Test
135 - post/arch Symlink to architecture specific Power On Self Test
136 - post/arch-ppc PowerPC architecture specific Power On Self Test
137 - post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138 - post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139 - rtc Real Time Clock drivers
140 - tools Tools to build S-Record or U-Boot images, etc.
142 - cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
143 - cpu/arm925t Files specific to ARM 925 CPUs
144 - cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
145 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
146 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
147 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
148 - cpu/ppc4xx Files specific to IBM 4xx CPUs
151 - board/LEOX/ Files specific to boards manufactured by The LEOX team
152 - board/LEOX/elpt860 Files specific to ELPT860 boards
154 Files specific to RPXClassic boards
155 - board/RPXlite Files specific to RPXlite boards
156 - board/at91rm9200dk Files specific to AT91RM9200DK boards
157 - board/c2mon Files specific to c2mon boards
158 - board/cmi Files specific to cmi boards
159 - board/cogent Files specific to Cogent boards
160 (need further configuration)
161 Files specific to CPCIISER4 boards
162 - board/cpu86 Files specific to CPU86 boards
163 - board/cray/ Files specific to boards manufactured by Cray
164 - board/cray/L1 Files specific to L1 boards
165 - board/cu824 Files specific to CU824 boards
166 - board/ebony Files specific to IBM Ebony board
167 - board/eric Files specific to ERIC boards
168 - board/esd/ Files specific to boards manufactured by ESD
169 - board/esd/adciop Files specific to ADCIOP boards
170 - board/esd/ar405 Files specific to AR405 boards
171 - board/esd/canbt Files specific to CANBT boards
172 - board/esd/cpci405 Files specific to CPCI405 boards
173 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
174 - board/esd/common Common files for ESD boards
175 - board/esd/dasa_sim Files specific to DASA_SIM boards
176 - board/esd/du405 Files specific to DU405 boards
177 - board/esd/ocrtc Files specific to OCRTC boards
178 - board/esd/pci405 Files specific to PCI405 boards
180 Files specific to ESTEEM192E boards
181 - board/etx094 Files specific to ETX_094 boards
183 Files specific to EVB64260 boards
184 - board/fads Files specific to FADS boards
185 - board/flagadm Files specific to FLAGADM boards
186 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
187 - board/genietv Files specific to GENIETV boards
188 - board/gth Files specific to GTH boards
189 - board/hermes Files specific to HERMES boards
190 - board/hymod Files specific to HYMOD boards
191 - board/icu862 Files specific to ICU862 boards
192 - board/ip860 Files specific to IP860 boards
194 Files specific to Interphase4539 boards
195 - board/ivm Files specific to IVMS8/IVML24 boards
196 - board/lantec Files specific to LANTEC boards
197 - board/lwmon Files specific to LWMON boards
198 - board/mbx8xx Files specific to MBX boards
200 Files specific to MPC8260ADS and PQ2FADS-ZU boards
201 - board/mpl/ Files specific to boards manufactured by MPL
202 - board/mpl/common Common files for MPL boards
203 - board/mpl/pip405 Files specific to PIP405 boards
204 - board/mpl/mip405 Files specific to MIP405 boards
205 - board/musenki Files specific to MUSEKNI boards
206 - board/mvs1 Files specific to MVS1 boards
207 - board/nx823 Files specific to NX823 boards
208 - board/oxc Files specific to OXC boards
210 Files specific to OMAP 1510 Innovator boards
211 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
212 - board/pm826 Files specific to PM826 boards
214 Files specific to PPMC8260 boards
216 Files specific to RPXsuper boards
218 Files specific to RSDproto boards
220 Files specific to Sandpoint boards
221 - board/sbc8260 Files specific to SBC8260 boards
222 - board/sacsng Files specific to SACSng boards
223 - board/siemens Files specific to boards manufactured by Siemens AG
224 - board/siemens/CCM Files specific to CCM boards
225 - board/siemens/IAD210 Files specific to IAD210 boards
226 - board/siemens/SCM Files specific to SCM boards
227 - board/siemens/pcu_e Files specific to PCU_E boards
228 - board/sixnet Files specific to SIXNET boards
229 - board/spd8xx Files specific to SPD8xxTS boards
230 - board/tqm8260 Files specific to TQM8260 boards
231 - board/tqm8xx Files specific to TQM8xxL boards
232 - board/w7o Files specific to W7O boards
234 Files specific to Walnut405 boards
235 - board/westel/ Files specific to boards manufactured by Westel Wireless
236 - board/westel/amx860 Files specific to AMX860 boards
237 - board/utx8245 Files specific to UTX8245 boards
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the cpu type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one of
301 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
303 or CONFIG_MPC824X, CONFIG_MPC8260
317 - Board Type: Define exactly one of
319 PowerPC based boards:
320 ---------------------
322 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
323 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
324 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
325 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
326 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
327 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
328 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
329 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
330 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
331 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
332 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
333 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
334 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
335 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
336 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
337 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
338 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
339 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
340 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
341 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
342 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
343 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
344 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
345 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
346 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
347 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
348 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
349 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
350 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
351 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
352 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
353 CONFIG_NETVIA, CONFIG_RBC823
358 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
359 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
360 CONFIG_INNOVATOROMAP1510,
361 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
362 CONFIG_TRAB, CONFIG_AT91RM9200DK
365 - CPU Module Type: (if CONFIG_COGENT is defined)
366 Define exactly one of
368 --- FIXME --- not tested yet:
369 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
370 CONFIG_CMA287_23, CONFIG_CMA287_50
372 - Motherboard Type: (if CONFIG_COGENT is defined)
373 Define exactly one of
374 CONFIG_CMA101, CONFIG_CMA102
376 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
377 Define one or more of
380 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
381 Define one or more of
382 CONFIG_LCD_HEARTBEAT - update a character position on
383 the lcd display every second with
386 - Board flavour: (if CONFIG_MPC8260ADS is defined)
389 CFG_8260ADS - original MPC8260ADS
390 CFG_8266ADS - MPC8266ADS (untested)
391 CFG_PQ2FADS - PQ2FADS-ZU
394 - MPC824X Family Member (if CONFIG_MPC824X is defined)
395 Define exactly one of
396 CONFIG_MPC8240, CONFIG_MPC8245
398 - 8xx CPU Options: (if using an 8xx cpu)
399 Define one or more of
400 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
401 no 32KHz reference PIT/RTC clock
406 U-Boot stores all clock information in Hz
407 internally. For binary compatibility with older Linux
408 kernels (which expect the clocks passed in the
409 bd_info data to be in MHz) the environment variable
410 "clocks_in_mhz" can be defined so that U-Boot
411 converts clock data to MHZ before passing it to the
414 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
415 "clocks_in_mhz=1" is automatically included in the
419 Depending on board, define exactly one serial port
420 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
421 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
422 console by defining CONFIG_8xx_CONS_NONE
424 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
425 port routines must be defined elsewhere
426 (i.e. serial_init(), serial_getc(), ...)
429 Enables console device for a color framebuffer. Needs following
430 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
431 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
433 VIDEO_HW_RECTFILL graphic chip supports
436 VIDEO_HW_BITBLT graphic chip supports
437 bit-blit (cf. smiLynxEM)
438 VIDEO_VISIBLE_COLS visible pixel columns
440 VIDEO_VISIBLE_ROWS visible pixel rows
441 VIDEO_PIXEL_SIZE bytes per pixel
442 VIDEO_DATA_FORMAT graphic data format
443 (0-5, cf. cfb_console.c)
444 VIDEO_FB_ADRS framebuffer address
445 VIDEO_KBD_INIT_FCT keyboard int fct
446 (i.e. i8042_kbd_init())
447 VIDEO_TSTC_FCT test char fct
449 VIDEO_GETC_FCT get char fct
451 CONFIG_CONSOLE_CURSOR cursor drawing on/off
452 (requires blink timer
454 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
455 CONFIG_CONSOLE_TIME display time/date info in
457 (requires CFG_CMD_DATE)
458 CONFIG_VIDEO_LOGO display Linux logo in
460 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
461 linux_logo.h for logo.
462 Requires CONFIG_VIDEO_LOGO
463 CONFIG_CONSOLE_EXTRA_INFO
464 addional board info beside
467 When CONFIG_CFB_CONSOLE is defined, video console is
468 default i/o. Serial console can be forced with
469 environment 'console=serial'.
472 CONFIG_BAUDRATE - in bps
473 Select one of the baudrates listed in
474 CFG_BAUDRATE_TABLE, see below.
476 - Interrupt driven serial port input:
477 CONFIG_SERIAL_SOFTWARE_FIFO
480 Use an interrupt handler for receiving data on the
481 serial port. It also enables using hardware handshake
482 (RTS/CTS) and UART's built-in FIFO. Set the number of
483 bytes the interrupt driven input buffer should have.
485 Set to 0 to disable this feature (this is the default).
486 This will also disable hardware handshake.
488 - Console UART Number:
492 If defined internal UART1 (and not UART0) is used
493 as default U-Boot console.
495 - Boot Delay: CONFIG_BOOTDELAY - in seconds
496 Delay before automatically booting the default image;
497 set to -1 to disable autoboot.
499 See doc/README.autoboot for these options that
500 work with CONFIG_BOOTDELAY. None are required.
501 CONFIG_BOOT_RETRY_TIME
502 CONFIG_BOOT_RETRY_MIN
503 CONFIG_AUTOBOOT_KEYED
504 CONFIG_AUTOBOOT_PROMPT
505 CONFIG_AUTOBOOT_DELAY_STR
506 CONFIG_AUTOBOOT_STOP_STR
507 CONFIG_AUTOBOOT_DELAY_STR2
508 CONFIG_AUTOBOOT_STOP_STR2
509 CONFIG_ZERO_BOOTDELAY_CHECK
510 CONFIG_RESET_TO_RETRY
514 Only needed when CONFIG_BOOTDELAY is enabled;
515 define a command string that is automatically executed
516 when no character is read on the console interface
517 within "Boot Delay" after reset.
520 This can be used to pass arguments to the bootm
521 command. The value of CONFIG_BOOTARGS goes into the
522 environment value "bootargs".
524 CONFIG_RAMBOOT and CONFIG_NFSBOOT
525 The value of these goes into the environment as
526 "ramboot" and "nfsboot" respectively, and can be used
527 as a convenience, when switching between booting from
533 When this option is #defined, the existence of the
534 environment variable "preboot" will be checked
535 immediately before starting the CONFIG_BOOTDELAY
536 countdown and/or running the auto-boot command resp.
537 entering interactive mode.
539 This feature is especially useful when "preboot" is
540 automatically generated or modified. For an example
541 see the LWMON board specific code: here "preboot" is
542 modified when the user holds down a certain
543 combination of keys on the (special) keyboard when
546 - Serial Download Echo Mode:
548 If defined to 1, all characters received during a
549 serial download (using the "loads" command) are
550 echoed back. This might be needed by some terminal
551 emulations (like "cu"), but may as well just take
552 time on others. This setting #define's the initial
553 value of the "loads_echo" environment variable.
555 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
557 Select one of the baudrates listed in
558 CFG_BAUDRATE_TABLE, see below.
562 Most monitor functions can be selected (or
563 de-selected) by adjusting the definition of
564 CONFIG_COMMANDS; to select individual functions,
565 #define CONFIG_COMMANDS by "OR"ing any of the
568 #define enables commands:
569 -------------------------
570 CFG_CMD_ASKENV * ask for env variable
572 CFG_CMD_BEDBUG Include BedBug Debugger
574 CFG_CMD_CACHE icache, dcache
575 CFG_CMD_CONSOLE coninfo
576 CFG_CMD_DATE * support for RTC, date/time...
577 CFG_CMD_DHCP DHCP support
578 CFG_CMD_ECHO * echo arguments
579 CFG_CMD_EEPROM * EEPROM read/write support
580 CFG_CMD_ELF bootelf, bootvx
582 CFG_CMD_FDC * Floppy Disk Support
583 CFG_CMD_FAT FAT partition support
584 CFG_CMD_FDOS * Dos diskette Support
585 CFG_CMD_FLASH flinfo, erase, protect
586 CFG_CMD_FPGA FPGA device initialization support
587 CFG_CMD_I2C * I2C serial bus support
588 CFG_CMD_IDE * IDE harddisk support
590 CFG_CMD_IMMAP * IMMR dump support
591 CFG_CMD_IRQ * irqinfo
595 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
597 CFG_CMD_MMC MMC memory mapped support
598 CFG_CMD_MII MII utility commands
599 CFG_CMD_NET bootp, tftpboot, rarpboot
600 CFG_CMD_PCI * pciinfo
601 CFG_CMD_PCMCIA * PCMCIA support
602 CFG_CMD_REGINFO * Register dump
603 CFG_CMD_RUN run command in env variable
604 CFG_CMD_SCSI * SCSI Support
605 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
606 CFG_CMD_SPI * SPI serial bus support
607 CFG_CMD_USB * USB support
608 CFG_CMD_BSP * Board SPecific functions
609 -----------------------------------------------
612 CFG_CMD_DFL Default configuration; at the moment
613 this is includes all commands, except
614 the ones marked with "*" in the list
617 If you don't define CONFIG_COMMANDS it defaults to
618 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
619 override the default settings in the respective
622 EXAMPLE: If you want all functions except of network
623 support you can write:
625 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
628 Note: Don't enable the "icache" and "dcache" commands
629 (configuration option CFG_CMD_CACHE) unless you know
630 what you (and your U-Boot users) are doing. Data
631 cache cannot be enabled on systems like the 8xx or
632 8260 (where accesses to the IMMR region must be
633 uncached), and it cannot be disabled on all other
634 systems where we (mis-) use the data cache to hold an
635 initial stack and some data.
638 XXX - this list needs to get updated!
642 If this variable is defined, it enables watchdog
643 support. There must support in the platform specific
644 code for a watchdog. For the 8xx and 8260 CPUs, the
645 SIU Watchdog feature is enabled in the SYPCR
649 CONFIG_VERSION_VARIABLE
650 If this variable is defined, an environment variable
651 named "ver" is created by U-Boot showing the U-Boot
652 version as printed by the "version" command.
653 This variable is readonly.
657 When CFG_CMD_DATE is selected, the type of the RTC
658 has to be selected, too. Define exactly one of the
661 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
662 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
663 CONFIG_RTC_MC146818 - use MC146818 RTC
664 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
665 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
666 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
667 CONFIG_RTC_DS164x - use Dallas DS164x RTC
669 Note that if the RTC uses I2C, then the I2C interface
670 must also be configured. See I2C Support, below.
674 When CONFIG_TIMESTAMP is selected, the timestamp
675 (date and time) of an image is printed by image
676 commands like bootm or iminfo. This option is
677 automatically enabled when you select CFG_CMD_DATE .
680 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
681 and/or CONFIG_ISO_PARTITION
683 If IDE or SCSI support is enabled (CFG_CMD_IDE or
684 CFG_CMD_SCSI) you must configure support for at least
685 one partition type as well.
688 CONFIG_IDE_RESET_ROUTINE
690 Set this to define that instead of a reset Pin, the
691 routine ide_set_reset(int idereset) will be used.
696 Set this to enable ATAPI support.
699 At the moment only there is only support for the
700 SYM53C8XX SCSI controller; define
701 CONFIG_SCSI_SYM53C8XX to enable it.
703 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
704 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
705 CFG_SCSI_MAX_LUN] can be adjusted to define the
706 maximum numbers of LUNs, SCSI ID's and target
708 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
710 - NETWORK Support (PCI):
712 Support for Intel 8254x gigabit chips.
715 Support for Intel 82557/82559/82559ER chips.
716 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
717 write routine for first time initialisation.
720 Support for Digital 2114x chips.
721 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
722 modem chip initialisation (KS8761/QS6611).
725 Support for National dp83815 chips.
728 Support for National dp8382[01] gigabit chips.
730 - NETWORK Support (other):
732 CONFIG_DRIVER_LAN91C96
733 Support for SMSC's LAN91C96 chips.
736 Define this to hold the physical address
737 of the LAN91C96's I/O space
739 CONFIG_LAN91C96_USE_32_BIT
740 Define this to enable 32 bit addressing
743 At the moment only the UHCI host controller is
744 supported (PIP405, MIP405); define
745 CONFIG_USB_UHCI to enable it.
746 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
747 end define CONFIG_USB_STORAGE to enable the USB
750 Supported are USB Keyboards and USB Floppy drives
754 The MMC controller on the Intel PXA is supported. To
755 enable this define CONFIG_MMC. The MMC can be
756 accessed from the boot prompt by mapping the device
757 to physical memory similar to flash. Command line is
758 enabled with CFG_CMD_MMC. The MMC driver also works with
759 the FAT fs. This is enabled with CFG_CMD_FAT.
764 Define this to enable standard (PC-Style) keyboard
768 Standard PC keyboard driver with US (is default) and
769 GERMAN key layout (switch via environment 'keymap=de') support.
770 Export function i8042_kbd_init, i8042_tstc and i8042_getc
771 for cfb_console. Supports cursor blinking.
776 Define this to enable video support (for output to
781 Enable Chips & Technologies 69000 Video chip
783 CONFIG_VIDEO_SMI_LYNXEM
784 Enable Silicon Motion SMI 712/710/810 Video chip
785 Videomode are selected via environment 'videomode' with
786 standard LiLo mode numbers.
787 Following modes are supported (* is default):
789 800x600 1024x768 1280x1024
790 256 (8bit) 303* 305 307
791 65536 (16bit) 314 317 31a
792 16,7 Mill (24bit) 315 318 31b
793 (i.e. setenv videomode 317; saveenv; reset;)
795 CONFIG_VIDEO_SED13806
796 Enable Epson SED13806 driver. This driver supports 8bpp
797 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
798 or CONFIG_VIDEO_SED13806_16BPP
803 Define this to enable a custom keyboard support.
804 This simply calls drv_keyboard_init() which must be
805 defined in your board-specific files.
806 The only board using this so far is RBC823.
808 - LCD Support: CONFIG_LCD
810 Define this to enable LCD support (for output to LCD
811 display); also select one of the supported displays
812 by defining one of these:
814 CONFIG_NEC_NL6648AC33:
816 NEC NL6648AC33-18. Active, color, single scan.
818 CONFIG_NEC_NL6648BC20
820 NEC NL6648BC20-08. 6.5", 640x480.
821 Active, color, single scan.
825 Sharp 320x240. Active, color, single scan.
826 It isn't 16x9, and I am not sure what it is.
828 CONFIG_SHARP_LQ64D341
830 Sharp LQ64D341 display, 640x480.
831 Active, color, single scan.
835 HLD1045 display, 640x480.
836 Active, color, single scan.
840 Optrex CBL50840-2 NF-FW 99 22 M5
842 Hitachi LMG6912RPFC-00T
846 320x240. Black & white.
848 Normally display is black on white background; define
849 CFG_WHITE_ON_BLACK to get it inverted.
851 - Spash Screen Support: CONFIG_SPLASH_SCREEN
853 If this option is set, the environment is checked for
854 a variable "splashimage". If found, the usual display
855 of logo, copyright and system information on the LCD
856 is supressed and the BMP image at the address
857 specified in "splashimage" is loaded instead. The
858 console is redirected to the "nulldev", too. This
859 allows for a "silent" boot where a splash screen is
860 loaded very quickly after power-on.
868 Define a default value for ethernet address to use
869 for the respective ethernet interface, in case this
870 is not determined automatically.
875 Define a default value for the IP address to use for
876 the default ethernet interface, in case this is not
877 determined through e.g. bootp.
882 Defines a default value for theIP address of a TFTP
883 server to contact when using the "tftboot" command.
885 - BOOTP Recovery Mode:
886 CONFIG_BOOTP_RANDOM_DELAY
888 If you have many targets in a network that try to
889 boot using BOOTP, you may want to avoid that all
890 systems send out BOOTP requests at precisely the same
891 moment (which would happen for instance at recovery
892 from a power failure, when all systems will try to
893 boot, thus flooding the BOOTP server. Defining
894 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
895 inserted before sending out BOOTP requests. The
896 following delays are insterted then:
898 1st BOOTP request: delay 0 ... 1 sec
899 2nd BOOTP request: delay 0 ... 2 sec
900 3rd BOOTP request: delay 0 ... 4 sec
902 BOOTP requests: delay 0 ... 8 sec
904 - Status LED: CONFIG_STATUS_LED
906 Several configurations allow to display the current
907 status using a LED. For instance, the LED will blink
908 fast while running U-Boot code, stop blinking as
909 soon as a reply to a BOOTP request was received, and
910 start blinking slow once the Linux kernel is running
911 (supported by a status LED driver in the Linux
912 kernel). Defining CONFIG_STATUS_LED enables this
915 - CAN Support: CONFIG_CAN_DRIVER
917 Defining CONFIG_CAN_DRIVER enables CAN driver support
918 on those systems that support this (optional)
919 feature, like the TQM8xxL modules.
921 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
923 These enable I2C serial bus commands. Defining either of
924 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
925 include the appropriate I2C driver for the selected cpu.
927 This will allow you to use i2c commands at the u-boot
928 command line (as long as you set CFG_CMD_I2C in
929 CONFIG_COMMANDS) and communicate with i2c based realtime
930 clock chips. See common/cmd_i2c.c for a description of the
931 command line interface.
933 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
935 CONFIG_SOFT_I2C configures u-boot to use a software (aka
936 bit-banging) driver instead of CPM or similar hardware
939 There are several other quantities that must also be
940 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
942 In both cases you will need to define CFG_I2C_SPEED
943 to be the frequency (in Hz) at which you wish your i2c bus
944 to run and CFG_I2C_SLAVE to be the address of this node (ie
945 the cpu's i2c node address).
947 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
948 sets the cpu up as a master node and so its address should
949 therefore be cleared to 0 (See, eg, MPC823e User's Manual
950 p.16-473). So, set CFG_I2C_SLAVE to 0.
952 That's all that's required for CONFIG_HARD_I2C.
954 If you use the software i2c interface (CONFIG_SOFT_I2C)
955 then the following macros need to be defined (examples are
956 from include/configs/lwmon.h):
960 (Optional). Any commands necessary to enable the I2C
961 controller or configure ports.
963 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
967 (Only for MPC8260 CPU). The I/O port to use (the code
968 assumes both bits are on the same port). Valid values
969 are 0..3 for ports A..D.
973 The code necessary to make the I2C data line active
974 (driven). If the data line is open collector, this
977 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
981 The code necessary to make the I2C data line tri-stated
982 (inactive). If the data line is open collector, this
985 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
989 Code that returns TRUE if the I2C data line is high,
992 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
996 If <bit> is TRUE, sets the I2C data line high. If it
997 is FALSE, it clears it (low).
999 eg: #define I2C_SDA(bit) \
1000 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1001 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1005 If <bit> is TRUE, sets the I2C clock line high. If it
1006 is FALSE, it clears it (low).
1008 eg: #define I2C_SCL(bit) \
1009 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1010 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1014 This delay is invoked four times per clock cycle so this
1015 controls the rate of data transfer. The data rate thus
1016 is 1 / (I2C_DELAY * 4). Often defined to be something
1019 #define I2C_DELAY udelay(2)
1023 When a board is reset during an i2c bus transfer
1024 chips might think that the current transfer is still
1025 in progress. On some boards it is possible to access
1026 the i2c SCLK line directly, either by using the
1027 processor pin as a GPIO or by having a second pin
1028 connected to the bus. If this option is defined a
1029 custom i2c_init_board() routine in boards/xxx/board.c
1030 is run early in the boot sequence.
1032 - SPI Support: CONFIG_SPI
1034 Enables SPI driver (so far only tested with
1035 SPI EEPROM, also an instance works with Crystal A/D and
1036 D/As on the SACSng board)
1040 Enables extended (16-bit) SPI EEPROM addressing.
1041 (symmetrical to CONFIG_I2C_X)
1045 Enables a software (bit-bang) SPI driver rather than
1046 using hardware support. This is a general purpose
1047 driver that only requires three general I/O port pins
1048 (two outputs, one input) to function. If this is
1049 defined, the board configuration must define several
1050 SPI configuration items (port pins to use, etc). For
1051 an example, see include/configs/sacsng.h.
1053 - FPGA Support: CONFIG_FPGA_COUNT
1055 Specify the number of FPGA devices to support.
1059 Used to specify the types of FPGA devices. For
1061 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1063 CFG_FPGA_PROG_FEEDBACK
1065 Enable printing of hash marks during FPGA
1070 Enable checks on FPGA configuration interface busy
1071 status by the configuration function. This option
1072 will require a board or device specific function to
1077 If defined, a function that provides delays in the
1078 FPGA configuration driver.
1080 CFG_FPGA_CHECK_CTRLC
1082 Allow Control-C to interrupt FPGA configuration
1084 CFG_FPGA_CHECK_ERROR
1086 Check for configuration errors during FPGA bitfile
1087 loading. For example, abort during Virtex II
1088 configuration if the INIT_B line goes low (which
1089 indicated a CRC error).
1093 Maximum time to wait for the INIT_B line to deassert
1094 after PROB_B has been deasserted during a Virtex II
1095 FPGA configuration sequence. The default time is 500 mS.
1099 Maximum time to wait for BUSY to deassert during
1100 Virtex II FPGA configuration. The default is 5 mS.
1102 CFG_FPGA_WAIT_CONFIG
1104 Time to wait after FPGA configuration. The default is
1107 - FPGA Support: CONFIG_FPGA_COUNT
1109 Specify the number of FPGA devices to support.
1113 Used to specify the types of FPGA devices. For example,
1114 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1116 CFG_FPGA_PROG_FEEDBACK
1118 Enable printing of hash marks during FPGA configuration.
1122 Enable checks on FPGA configuration interface busy
1123 status by the configuration function. This option
1124 will require a board or device specific function to
1129 If defined, a function that provides delays in the FPGA
1130 configuration driver.
1132 CFG_FPGA_CHECK_CTRLC
1133 Allow Control-C to interrupt FPGA configuration
1135 CFG_FPGA_CHECK_ERROR
1137 Check for configuration errors during FPGA bitfile
1138 loading. For example, abort during Virtex II
1139 configuration if the INIT_B line goes low (which
1140 indicated a CRC error).
1144 Maximum time to wait for the INIT_B line to deassert
1145 after PROB_B has been deasserted during a Virtex II
1146 FPGA configuration sequence. The default time is 500
1151 Maximum time to wait for BUSY to deassert during
1152 Virtex II FPGA configuration. The default is 5 mS.
1154 CFG_FPGA_WAIT_CONFIG
1156 Time to wait after FPGA configuration. The default is
1159 - Configuration Management:
1162 If defined, this string will be added to the U-Boot
1163 version information (U_BOOT_VERSION)
1165 - Vendor Parameter Protection:
1167 U-Boot considers the values of the environment
1168 variables "serial#" (Board Serial Number) and
1169 "ethaddr" (Ethernet Address) to bb parameters that
1170 are set once by the board vendor / manufacturer, and
1171 protects these variables from casual modification by
1172 the user. Once set, these variables are read-only,
1173 and write or delete attempts are rejected. You can
1174 change this behviour:
1176 If CONFIG_ENV_OVERWRITE is #defined in your config
1177 file, the write protection for vendor parameters is
1178 completely disabled. Anybody can change or delete
1181 Alternatively, if you #define _both_ CONFIG_ETHADDR
1182 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1183 ethernet address is installed in the environment,
1184 which can be changed exactly ONCE by the user. [The
1185 serial# is unaffected by this, i. e. it remains
1191 Define this variable to enable the reservation of
1192 "protected RAM", i. e. RAM which is not overwritten
1193 by U-Boot. Define CONFIG_PRAM to hold the number of
1194 kB you want to reserve for pRAM. You can overwrite
1195 this default value by defining an environment
1196 variable "pram" to the number of kB you want to
1197 reserve. Note that the board info structure will
1198 still show the full amount of RAM. If pRAM is
1199 reserved, a new environment variable "mem" will
1200 automatically be defined to hold the amount of
1201 remaining RAM in a form that can be passed as boot
1202 argument to Linux, for instance like that:
1204 setenv bootargs ... mem=\$(mem)
1207 This way you can tell Linux not to use this memory,
1208 either, which results in a memory region that will
1209 not be affected by reboots.
1211 *WARNING* If your board configuration uses automatic
1212 detection of the RAM size, you must make sure that
1213 this memory test is non-destructive. So far, the
1214 following board configurations are known to be
1217 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1218 HERMES, IP860, RPXlite, LWMON, LANTEC,
1219 PCU_E, FLAGADM, TQM8260
1224 Define this variable to stop the system in case of a
1225 fatal error, so that you have to reset it manually.
1226 This is probably NOT a good idea for an embedded
1227 system where you want to system to reboot
1228 automatically as fast as possible, but it may be
1229 useful during development since you can try to debug
1230 the conditions that lead to the situation.
1232 CONFIG_NET_RETRY_COUNT
1234 This variable defines the number of retries for
1235 network operations like ARP, RARP, TFTP, or BOOTP
1236 before giving up the operation. If not defined, a
1237 default value of 5 is used.
1239 - Command Interpreter:
1242 Define this variable to enable the "hush" shell (from
1243 Busybox) as command line interpreter, thus enabling
1244 powerful command line syntax like
1245 if...then...else...fi conditionals or `&&' and '||'
1246 constructs ("shell scripts").
1248 If undefined, you get the old, much simpler behaviour
1249 with a somewhat smaller memory footprint.
1254 This defines the secondary prompt string, which is
1255 printed when the command interpreter needs more input
1256 to complete a command. Usually "> ".
1260 In the current implementation, the local variables
1261 space and global environment variables space are
1262 separated. Local variables are those you define by
1263 simply typing `name=value'. To access a local
1264 variable later on, you have write `$name' or
1265 `${name}'; to execute the contents of a variable
1266 directly type `$name' at the command prompt.
1268 Global environment variables are those you use
1269 setenv/printenv to work with. To run a command stored
1270 in such a variable, you need to use the run command,
1271 and you must not use the '$' sign to access them.
1273 To store commands and special characters in a
1274 variable, please use double quotation marks
1275 surrounding the whole text of the variable, instead
1276 of the backslashes before semicolons and special
1279 - Default Environment
1280 CONFIG_EXTRA_ENV_SETTINGS
1282 Define this to contain any number of null terminated
1283 strings (variable = value pairs) that will be part of
1284 the default enviroment compiled into the boot image.
1286 For example, place something like this in your
1287 board's config file:
1289 #define CONFIG_EXTRA_ENV_SETTINGS \
1293 Warning: This method is based on knowledge about the
1294 internal format how the environment is stored by the
1295 U-Boot code. This is NOT an official, exported
1296 interface! Although it is unlikely that this format
1297 will change soon, but there is no guarantee either.
1298 You better know what you are doing here.
1300 Note: overly (ab)use of the default environment is
1301 discouraged. Make sure to check other ways to preset
1302 the environment like the autoscript function or the
1306 CONFIG_HAS_DATAFLASH
1308 Defining this option enables DataFlash features and
1309 allows to read/write in Dataflash via the standard
1312 - Show boot progress
1313 CONFIG_SHOW_BOOT_PROGRESS
1315 Defining this option allows to add some board-
1316 specific code (calling a user-provided function
1317 "show_boot_progress(int)") that enables you to show
1318 the system's boot progress on some display (for
1319 example, some LED's) on your board. At the moment,
1320 the following checkpoints are implemented:
1323 1 common/cmd_bootm.c before attempting to boot an image
1324 -1 common/cmd_bootm.c Image header has bad magic number
1325 2 common/cmd_bootm.c Image header has correct magic number
1326 -2 common/cmd_bootm.c Image header has bad checksum
1327 3 common/cmd_bootm.c Image header has correct checksum
1328 -3 common/cmd_bootm.c Image data has bad checksum
1329 4 common/cmd_bootm.c Image data has correct checksum
1330 -4 common/cmd_bootm.c Image is for unsupported architecture
1331 5 common/cmd_bootm.c Architecture check OK
1332 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1333 6 common/cmd_bootm.c Image Type check OK
1334 -6 common/cmd_bootm.c gunzip uncompression error
1335 -7 common/cmd_bootm.c Unimplemented compression type
1336 7 common/cmd_bootm.c Uncompression OK
1337 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1338 8 common/cmd_bootm.c Image Type check OK
1339 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1340 9 common/cmd_bootm.c Start initial ramdisk verification
1341 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1342 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1343 10 common/cmd_bootm.c Ramdisk header is OK
1344 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1345 11 common/cmd_bootm.c Ramdisk data has correct checksum
1346 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1347 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1348 13 common/cmd_bootm.c Start multifile image verification
1349 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1350 15 common/cmd_bootm.c All preparation done, transferring control to OS
1352 -1 common/cmd_doc.c Bad usage of "doc" command
1353 -1 common/cmd_doc.c No boot device
1354 -1 common/cmd_doc.c Unknown Chip ID on boot device
1355 -1 common/cmd_doc.c Read Error on boot device
1356 -1 common/cmd_doc.c Image header has bad magic number
1358 -1 common/cmd_ide.c Bad usage of "ide" command
1359 -1 common/cmd_ide.c No boot device
1360 -1 common/cmd_ide.c Unknown boot device
1361 -1 common/cmd_ide.c Unknown partition table
1362 -1 common/cmd_ide.c Invalid partition type
1363 -1 common/cmd_ide.c Read Error on boot device
1364 -1 common/cmd_ide.c Image header has bad magic number
1366 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1372 [so far only for SMDK2400 and TRAB boards]
1374 - Modem support endable:
1375 CONFIG_MODEM_SUPPORT
1377 - RTS/CTS Flow control enable:
1380 - Modem debug support:
1381 CONFIG_MODEM_SUPPORT_DEBUG
1383 Enables debugging stuff (char screen[1024], dbg())
1384 for modem support. Useful only with BDI2000.
1388 In the target system modem support is enabled when a
1389 specific key (key combination) is pressed during
1390 power-on. Otherwise U-Boot will boot normally
1391 (autoboot). The key_pressed() fuction is called from
1392 board_init(). Currently key_pressed() is a dummy
1393 function, returning 1 and thus enabling modem
1396 If there are no modem init strings in the
1397 environment, U-Boot proceed to autoboot; the
1398 previous output (banner, info printfs) will be
1401 See also: doc/README.Modem
1404 Configuration Settings:
1405 -----------------------
1407 - CFG_LONGHELP: Defined when you want long help messages included;
1408 undefine this when you're short of memory.
1410 - CFG_PROMPT: This is what U-Boot prints on the console to
1411 prompt for user input.
1413 - CFG_CBSIZE: Buffer size for input from the Console
1415 - CFG_PBSIZE: Buffer size for Console output
1417 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1419 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1420 the application (usually a Linux kernel) when it is
1423 - CFG_BAUDRATE_TABLE:
1424 List of legal baudrate settings for this board.
1426 - CFG_CONSOLE_INFO_QUIET
1427 Suppress display of console information at boot.
1429 - CFG_CONSOLE_IS_IN_ENV
1430 If the board specific function
1431 extern int overwrite_console (void);
1432 returns 1, the stdin, stderr and stdout are switched to the
1433 serial port, else the settings in the environment are used.
1435 - CFG_CONSOLE_OVERWRITE_ROUTINE
1436 Enable the call to overwrite_console().
1438 - CFG_CONSOLE_ENV_OVERWRITE
1439 Enable overwrite of previous console environment settings.
1441 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1442 Begin and End addresses of the area used by the
1446 Enable an alternate, more extensive memory test.
1448 - CFG_TFTP_LOADADDR:
1449 Default load address for network file downloads
1451 - CFG_LOADS_BAUD_CHANGE:
1452 Enable temporary baudrate change while serial download
1455 Physical start address of SDRAM. _Must_ be 0 here.
1458 Physical start address of Motherboard I/O (if using a
1462 Physical start address of Flash memory.
1465 Physical start address of boot monitor code (set by
1466 make config files to be same as the text base address
1467 (TEXT_BASE) used when linking) - same as
1468 CFG_FLASH_BASE when booting from flash.
1471 Size of memory reserved for monitor code, used to
1472 determine _at_compile_time_ (!) if the environment is
1473 embedded within the U-Boot image, or in a separate
1477 Size of DRAM reserved for malloc() use.
1480 Maximum size of memory mapped by the startup code of
1481 the Linux kernel; all data that must be processed by
1482 the Linux kernel (bd_info, boot arguments, eventually
1483 initrd image) must be put below this limit.
1485 - CFG_MAX_FLASH_BANKS:
1486 Max number of Flash memory banks
1488 - CFG_MAX_FLASH_SECT:
1489 Max number of sectors on a Flash chip
1491 - CFG_FLASH_ERASE_TOUT:
1492 Timeout for Flash erase operations (in ms)
1494 - CFG_FLASH_WRITE_TOUT:
1495 Timeout for Flash write operations (in ms)
1497 - CFG_FLASH_LOCK_TOUT
1498 Timeout for Flash set sector lock bit operation (in ms)
1500 - CFG_FLASH_UNLOCK_TOUT
1501 Timeout for Flash clear lock bits operation (in ms)
1503 - CFG_FLASH_PROTECTION
1504 If defined, hardware flash sectors protection is used
1505 instead of U-Boot software protection.
1507 - CFG_DIRECT_FLASH_TFTP:
1509 Enable TFTP transfers directly to flash memory;
1510 without this option such a download has to be
1511 performed in two steps: (1) download to RAM, and (2)
1512 copy from RAM to flash.
1514 The two-step approach is usually more reliable, since
1515 you can check if the download worked before you erase
1516 the flash, but in some situations (when sytem RAM is
1517 too limited to allow for a tempory copy of the
1518 downloaded image) this option may be very useful.
1521 Define if the flash driver uses extra elements in the
1522 common flash structure for storing flash geometry
1524 - CFG_RX_ETH_BUFFER:
1525 Defines the number of ethernet receive buffers. On some
1526 ethernet controllers it is recommended to set this value
1527 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1528 buffers can be full shortly after enabling the interface
1529 on high ethernet traffic.
1530 Defaults to 4 if not defined.
1532 The following definitions that deal with the placement and management
1533 of environment data (variable area); in general, we support the
1534 following configurations:
1536 - CFG_ENV_IS_IN_FLASH:
1538 Define this if the environment is in flash memory.
1540 a) The environment occupies one whole flash sector, which is
1541 "embedded" in the text segment with the U-Boot code. This
1542 happens usually with "bottom boot sector" or "top boot
1543 sector" type flash chips, which have several smaller
1544 sectors at the start or the end. For instance, such a
1545 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1546 such a case you would place the environment in one of the
1547 4 kB sectors - with U-Boot code before and after it. With
1548 "top boot sector" type flash chips, you would put the
1549 environment in one of the last sectors, leaving a gap
1550 between U-Boot and the environment.
1554 Offset of environment data (variable area) to the
1555 beginning of flash memory; for instance, with bottom boot
1556 type flash chips the second sector can be used: the offset
1557 for this sector is given here.
1559 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1563 This is just another way to specify the start address of
1564 the flash sector containing the environment (instead of
1567 - CFG_ENV_SECT_SIZE:
1569 Size of the sector containing the environment.
1572 b) Sometimes flash chips have few, equal sized, BIG sectors.
1573 In such a case you don't want to spend a whole sector for
1578 If you use this in combination with CFG_ENV_IS_IN_FLASH
1579 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1580 of this flash sector for the environment. This saves
1581 memory for the RAM copy of the environment.
1583 It may also save flash memory if you decide to use this
1584 when your environment is "embedded" within U-Boot code,
1585 since then the remainder of the flash sector could be used
1586 for U-Boot code. It should be pointed out that this is
1587 STRONGLY DISCOURAGED from a robustness point of view:
1588 updating the environment in flash makes it always
1589 necessary to erase the WHOLE sector. If something goes
1590 wrong before the contents has been restored from a copy in
1591 RAM, your target system will be dead.
1593 - CFG_ENV_ADDR_REDUND
1596 These settings describe a second storage area used to hold
1597 a redundand copy of the environment data, so that there is
1598 a valid backup copy in case there is a power failure during
1599 a "saveenv" operation.
1601 BE CAREFUL! Any changes to the flash layout, and some changes to the
1602 source code will make it necessary to adapt <board>/u-boot.lds*
1606 - CFG_ENV_IS_IN_NVRAM:
1608 Define this if you have some non-volatile memory device
1609 (NVRAM, battery buffered SRAM) which you want to use for the
1615 These two #defines are used to determin the memory area you
1616 want to use for environment. It is assumed that this memory
1617 can just be read and written to, without any special
1620 BE CAREFUL! The first access to the environment happens quite early
1621 in U-Boot initalization (when we try to get the setting of for the
1622 console baudrate). You *MUST* have mappend your NVRAM area then, or
1625 Please note that even with NVRAM we still use a copy of the
1626 environment in RAM: we could work on NVRAM directly, but we want to
1627 keep settings there always unmodified except somebody uses "saveenv"
1628 to save the current settings.
1631 - CFG_ENV_IS_IN_EEPROM:
1633 Use this if you have an EEPROM or similar serial access
1634 device and a driver for it.
1639 These two #defines specify the offset and size of the
1640 environment area within the total memory of your EEPROM.
1642 - CFG_I2C_EEPROM_ADDR:
1643 If defined, specified the chip address of the EEPROM device.
1644 The default address is zero.
1646 - CFG_EEPROM_PAGE_WRITE_BITS:
1647 If defined, the number of bits used to address bytes in a
1648 single page in the EEPROM device. A 64 byte page, for example
1649 would require six bits.
1651 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1652 If defined, the number of milliseconds to delay between
1653 page writes. The default is zero milliseconds.
1655 - CFG_I2C_EEPROM_ADDR_LEN:
1656 The length in bytes of the EEPROM memory array address. Note
1657 that this is NOT the chip address length!
1660 The size in bytes of the EEPROM device.
1663 - CFG_SPI_INIT_OFFSET
1665 Defines offset to the initial SPI buffer area in DPRAM. The
1666 area is used at an early stage (ROM part) if the environment
1667 is configured to reside in the SPI EEPROM: We need a 520 byte
1668 scratch DPRAM area. It is used between the two initialization
1669 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1670 to be a good choice since it makes it far enough from the
1671 start of the data area as well as from the stack pointer.
1673 Please note that the environment is read-only as long as the monitor
1674 has been relocated to RAM and a RAM copy of the environment has been
1675 created; also, when using EEPROM you will have to use getenv_r()
1676 until then to read environment variables.
1678 The environment is protected by a CRC32 checksum. Before the monitor
1679 is relocated into RAM, as a result of a bad CRC you will be working
1680 with the compiled-in default environment - *silently*!!! [This is
1681 necessary, because the first environment variable we need is the
1682 "baudrate" setting for the console - if we have a bad CRC, we don't
1683 have any device yet where we could complain.]
1685 Note: once the monitor has been relocated, then it will complain if
1686 the default environment is used; a new CRC is computed as soon as you
1687 use the "saveenv" command to store a valid environment.
1690 Low Level (hardware related) configuration options:
1691 ---------------------------------------------------
1693 - CFG_CACHELINE_SIZE:
1694 Cache Line Size of the CPU.
1697 Default address of the IMMR after system reset.
1699 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1700 and RPXsuper) to be able to adjust the position of
1701 the IMMR register after a reset.
1703 - Floppy Disk Support:
1704 CFG_FDC_DRIVE_NUMBER
1706 the default drive number (default value 0)
1710 defines the spacing between fdc chipset registers
1715 defines the offset of register from address. It
1716 depends on which part of the data bus is connected to
1717 the fdc chipset. (default value 0)
1719 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1720 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1723 if CFG_FDC_HW_INIT is defined, then the function
1724 fdc_hw_init() is called at the beginning of the FDC
1725 setup. fdc_hw_init() must be provided by the board
1726 source code. It is used to make hardware dependant
1729 - CFG_IMMR: Physical address of the Internal Memory Mapped
1730 Register; DO NOT CHANGE! (11-4)
1731 [MPC8xx systems only]
1733 - CFG_INIT_RAM_ADDR:
1735 Start address of memory area tha can be used for
1736 initial data and stack; please note that this must be
1737 writable memory that is working WITHOUT special
1738 initialization, i. e. you CANNOT use normal RAM which
1739 will become available only after programming the
1740 memory controller and running certain initialization
1743 U-Boot uses the following memory types:
1744 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1745 - MPC824X: data cache
1746 - PPC4xx: data cache
1748 - CFG_GBL_DATA_OFFSET:
1750 Offset of the initial data structure in the memory
1751 area defined by CFG_INIT_RAM_ADDR. Usually
1752 CFG_GBL_DATA_OFFSET is chosen such that the initial
1753 data is located at the end of the available space
1754 (sometimes written as (CFG_INIT_RAM_END -
1755 CFG_INIT_DATA_SIZE), and the initial stack is just
1756 below that area (growing from (CFG_INIT_RAM_ADDR +
1757 CFG_GBL_DATA_OFFSET) downward.
1760 On the MPC824X (or other systems that use the data
1761 cache for initial memory) the address chosen for
1762 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1763 point to an otherwise UNUSED address space between
1764 the top of RAM and the start of the PCI space.
1766 - CFG_SIUMCR: SIU Module Configuration (11-6)
1768 - CFG_SYPCR: System Protection Control (11-9)
1770 - CFG_TBSCR: Time Base Status and Control (11-26)
1772 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1774 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1776 - CFG_SCCR: System Clock and reset Control Register (15-27)
1778 - CFG_OR_TIMING_SDRAM:
1782 periodic timer for refresh
1784 - CFG_DER: Debug Event Register (37-47)
1786 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1787 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1788 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1790 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1792 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1793 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1794 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1795 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1797 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1798 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1799 Machine Mode Register and Memory Periodic Timer
1800 Prescaler definitions (SDRAM timing)
1802 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1803 enable I2C microcode relocation patch (MPC8xx);
1804 define relocation offset in DPRAM [DSP2]
1806 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1807 enable SPI microcode relocation patch (MPC8xx);
1808 define relocation offset in DPRAM [SCC4]
1811 Use OSCM clock mode on MBX8xx board. Be careful,
1812 wrong setting might damage your board. Read
1813 doc/README.MBX before setting this variable!
1815 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1816 Offset of the bootmode word in DPRAM used by post
1817 (Power On Self Tests). This definition overrides
1818 #define'd default value in commproc.h resp.
1821 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1822 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1823 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1824 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1825 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1826 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1827 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1828 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1829 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1831 Building the Software:
1832 ======================
1834 Building U-Boot has been tested in native PPC environments (on a
1835 PowerBook G3 running LinuxPPC 2000) and in cross environments
1836 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1839 If you are not using a native PPC environment, it is assumed that you
1840 have the GNU cross compiling tools available in your path and named
1841 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1842 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1843 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1846 CROSS_COMPILE = ppc_4xx-
1849 U-Boot is intended to be simple to build. After installing the
1850 sources you must configure U-Boot for one specific board type. This
1855 where "NAME_config" is the name of one of the existing
1856 configurations; the following names are supported:
1858 ADCIOP_config GTH_config TQM850L_config
1859 ADS860_config IP860_config TQM855L_config
1860 AR405_config IVML24_config TQM860L_config
1861 CANBT_config IVMS8_config WALNUT405_config
1862 CPCI405_config LANTEC_config cogent_common_config
1863 CPCIISER4_config MBX_config cogent_mpc8260_config
1864 CU824_config MBX860T_config cogent_mpc8xx_config
1865 ESTEEM192E_config RPXlite_config hermes_config
1866 ETX094_config RPXsuper_config hymod_config
1867 FADS823_config SM850_config lwmon_config
1868 FADS850SAR_config SPD823TS_config pcu_e_config
1869 FADS860T_config SXNI855T_config rsdproto_config
1870 FPS850L_config Sandpoint8240_config sbc8260_config
1871 GENIETV_config TQM823L_config PIP405_config
1872 GEN860T_config EBONY_config FPS860L_config
1873 ELPT860_config cmi_mpc5xx_config NETVIA_config
1874 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
1876 Note: for some board special configuration names may exist; check if
1877 additional information is available from the board vendor; for
1878 instance, the TQM8xxL systems run normally at 50 MHz and use a
1879 SCC for 10baseT ethernet; there are also systems with 80 MHz
1880 CPU clock, and an optional Fast Ethernet module is available
1881 for CPU's with FEC. You can select such additional "features"
1882 when chosing the configuration, i. e.
1885 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1887 make TQM860L_FEC_config
1888 - will configure for a TQM860L at 50MHz with FEC for ethernet
1890 make TQM860L_80MHz_config
1891 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1894 make TQM860L_FEC_80MHz_config
1895 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1897 make TQM823L_LCD_config
1898 - will configure for a TQM823L with U-Boot console on LCD
1900 make TQM823L_LCD_80MHz_config
1901 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1906 Finally, type "make all", and you should get some working U-Boot
1907 images ready for downlod to / installation on your system:
1909 - "u-boot.bin" is a raw binary image
1910 - "u-boot" is an image in ELF binary format
1911 - "u-boot.srec" is in Motorola S-Record format
1914 Please be aware that the Makefiles assume you are using GNU make, so
1915 for instance on NetBSD you might need to use "gmake" instead of
1919 If the system board that you have is not listed, then you will need
1920 to port U-Boot to your hardware platform. To do this, follow these
1923 1. Add a new configuration option for your board to the toplevel
1924 "Makefile" and to the "MAKEALL" script, using the existing
1925 entries as examples. Note that here and at many other places
1926 boards and other names are listed alphabetically sorted. Please
1928 2. Create a new directory to hold your board specific code. Add any
1929 files you need. In your board directory, you will need at least
1930 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1931 3. Create a new configuration file "include/configs/<board>.h" for
1933 3. If you're porting U-Boot to a new CPU, then also create a new
1934 directory to hold your CPU specific code. Add any files you need.
1935 4. Run "make <board>_config" with your new name.
1936 5. Type "make", and you should get a working "u-boot.srec" file
1937 to be installed on your target system.
1938 6. Debug and solve any problems that might arise.
1939 [Of course, this last step is much harder than it sounds.]
1942 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1943 ==============================================================
1945 If you have modified U-Boot sources (for instance added a new board
1946 or support for new devices, a new CPU, etc.) you are expected to
1947 provide feedback to the other developers. The feedback normally takes
1948 the form of a "patch", i. e. a context diff against a certain (latest
1949 official or latest in CVS) version of U-Boot sources.
1951 But before you submit such a patch, please verify that your modifi-
1952 cation did not break existing code. At least make sure that *ALL* of
1953 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1954 just run the "MAKEALL" script, which will configure and build U-Boot
1955 for ALL supported system. Be warned, this will take a while. You can
1956 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1957 environment variable to the script, i. e. to use the cross tools from
1958 MontaVista's Hard Hat Linux you can type
1960 CROSS_COMPILE=ppc_8xx- MAKEALL
1962 or to build on a native PowerPC system you can type
1964 CROSS_COMPILE=' ' MAKEALL
1966 See also "U-Boot Porting Guide" below.
1969 Monitor Commands - Overview:
1970 ============================
1972 go - start application at address 'addr'
1973 run - run commands in an environment variable
1974 bootm - boot application image from memory
1975 bootp - boot image via network using BootP/TFTP protocol
1976 tftpboot- boot image via network using TFTP protocol
1977 and env variables "ipaddr" and "serverip"
1978 (and eventually "gatewayip")
1979 rarpboot- boot image via network using RARP/TFTP protocol
1980 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1981 loads - load S-Record file over serial line
1982 loadb - load binary file over serial line (kermit mode)
1984 mm - memory modify (auto-incrementing)
1985 nm - memory modify (constant address)
1986 mw - memory write (fill)
1988 cmp - memory compare
1989 crc32 - checksum calculation
1990 imd - i2c memory display
1991 imm - i2c memory modify (auto-incrementing)
1992 inm - i2c memory modify (constant address)
1993 imw - i2c memory write (fill)
1994 icrc32 - i2c checksum calculation
1995 iprobe - probe to discover valid I2C chip addresses
1996 iloop - infinite loop on address range
1997 isdram - print SDRAM configuration information
1998 sspi - SPI utility commands
1999 base - print or set address offset
2000 printenv- print environment variables
2001 setenv - set environment variables
2002 saveenv - save environment variables to persistent storage
2003 protect - enable or disable FLASH write protection
2004 erase - erase FLASH memory
2005 flinfo - print FLASH memory information
2006 bdinfo - print Board Info structure
2007 iminfo - print header information for application image
2008 coninfo - print console devices and informations
2009 ide - IDE sub-system
2010 loop - infinite loop on address range
2011 mtest - simple RAM test
2012 icache - enable or disable instruction cache
2013 dcache - enable or disable data cache
2014 reset - Perform RESET of the CPU
2015 echo - echo args to console
2016 version - print monitor version
2017 help - print online help
2018 ? - alias for 'help'
2021 Monitor Commands - Detailed Description:
2022 ========================================
2026 For now: just type "help <command>".
2029 Environment Variables:
2030 ======================
2032 U-Boot supports user configuration using Environment Variables which
2033 can be made persistent by saving to Flash memory.
2035 Environment Variables are set using "setenv", printed using
2036 "printenv", and saved to Flash using "saveenv". Using "setenv"
2037 without a value can be used to delete a variable from the
2038 environment. As long as you don't save the environment you are
2039 working with an in-memory copy. In case the Flash area containing the
2040 environment is erased by accident, a default environment is provided.
2042 Some configuration options can be set using Environment Variables:
2044 baudrate - see CONFIG_BAUDRATE
2046 bootdelay - see CONFIG_BOOTDELAY
2048 bootcmd - see CONFIG_BOOTCOMMAND
2050 bootargs - Boot arguments when booting an RTOS image
2052 bootfile - Name of the image to load with TFTP
2054 autoload - if set to "no" (any string beginning with 'n'),
2055 "bootp" will just load perform a lookup of the
2056 configuration from the BOOTP server, but not try to
2057 load any image using TFTP
2059 autostart - if set to "yes", an image loaded using the "bootp",
2060 "rarpboot", "tftpboot" or "diskboot" commands will
2061 be automatically started (by internally calling
2064 If set to "no", a standalone image passed to the
2065 "bootm" command will be copied to the load address
2066 (and eventually uncompressed), but NOT be started.
2067 This can be used to load and uncompress arbitrary
2070 initrd_high - restrict positioning of initrd images:
2071 If this variable is not set, initrd images will be
2072 copied to the highest possible address in RAM; this
2073 is usually what you want since it allows for
2074 maximum initrd size. If for some reason you want to
2075 make sure that the initrd image is loaded below the
2076 CFG_BOOTMAPSZ limit, you can set this environment
2077 variable to a value of "no" or "off" or "0".
2078 Alternatively, you can set it to a maximum upper
2079 address to use (U-Boot will still check that it
2080 does not overwrite the U-Boot stack and data).
2082 For instance, when you have a system with 16 MB
2083 RAM, and want to reseve 4 MB from use by Linux,
2084 you can do this by adding "mem=12M" to the value of
2085 the "bootargs" variable. However, now you must make
2086 sure, that the initrd image is placed in the first
2087 12 MB as well - this can be done with
2089 setenv initrd_high 00c00000
2091 If you set initrd_high to 0xFFFFFFFF, this is an
2092 indication to U-Boot that all addresses are legal
2093 for the Linux kernel, including addresses in flash
2094 memory. In this case U-Boot will NOT COPY the
2095 ramdisk at all. This may be useful to reduce the
2096 boot time on your system, but requires that this
2097 feature is supported by your Linux kernel.
2099 ipaddr - IP address; needed for tftpboot command
2101 loadaddr - Default load address for commands like "bootp",
2102 "rarpboot", "tftpboot", "loadb" or "diskboot"
2104 loads_echo - see CONFIG_LOADS_ECHO
2106 serverip - TFTP server IP address; needed for tftpboot command
2108 bootretry - see CONFIG_BOOT_RETRY_TIME
2110 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2112 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2115 The following environment variables may be used and automatically
2116 updated by the network boot commands ("bootp" and "rarpboot"),
2117 depending the information provided by your boot server:
2119 bootfile - see above
2120 dnsip - IP address of your Domain Name Server
2121 gatewayip - IP address of the Gateway (Router) to use
2122 hostname - Target hostname
2124 netmask - Subnet Mask
2125 rootpath - Pathname of the root filesystem on the NFS server
2126 serverip - see above
2129 There are two special Environment Variables:
2131 serial# - contains hardware identification information such
2132 as type string and/or serial number
2133 ethaddr - Ethernet address
2135 These variables can be set only once (usually during manufacturing of
2136 the board). U-Boot refuses to delete or overwrite these variables
2137 once they have been set once.
2140 Further special Environment Variables:
2142 ver - Contains the U-Boot version string as printed
2143 with the "version" command. This variable is
2144 readonly (see CONFIG_VERSION_VARIABLE).
2147 Please note that changes to some configuration parameters may take
2148 only effect after the next boot (yes, that's just like Windoze :-).
2151 Command Line Parsing:
2152 =====================
2154 There are two different command line parsers available with U-Boot:
2155 the old "simple" one, and the much more pwerful "hush" shell:
2157 Old, simple command line parser:
2158 --------------------------------
2160 - supports environment variables (through setenv / saveenv commands)
2161 - several commands on one line, separated by ';'
2162 - variable substitution using "... $(name) ..." syntax
2163 - special characters ('$', ';') can be escaped by prefixing with '\',
2165 setenv bootcmd bootm \$(address)
2166 - You can also escape text by enclosing in single apostrophes, for example:
2167 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2172 - similar to Bourne shell, with control structures like
2173 if...then...else...fi, for...do...done; while...do...done,
2174 until...do...done, ...
2175 - supports environment ("global") variables (through setenv / saveenv
2176 commands) and local shell variables (through standard shell syntax
2177 "name=value"); only environment variables can be used with "run"
2183 (1) If a command line (or an environment variable executed by a "run"
2184 command) contains several commands separated by semicolon, and
2185 one of these commands fails, then the remaining commands will be
2188 (2) If you execute several variables with one call to run (i. e.
2189 calling run with a list af variables as arguments), any failing
2190 command will cause "run" to terminate, i. e. the remaining
2191 variables are not executed.
2193 Note for Redundant Ethernet Interfaces:
2194 =======================================
2196 Some boards come with redundand ethernet interfaces; U-Boot supports
2197 such configurations and is capable of automatic selection of a
2198 "working" interface when needed. MAC assignemnt works as follows:
2200 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2201 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2202 "eth1addr" (=>eth1), "eth2addr", ...
2204 If the network interface stores some valid MAC address (for instance
2205 in SROM), this is used as default address if there is NO correspon-
2206 ding setting in the environment; if the corresponding environment
2207 variable is set, this overrides the settings in the card; that means:
2209 o If the SROM has a valid MAC address, and there is no address in the
2210 environment, the SROM's address is used.
2212 o If there is no valid address in the SROM, and a definition in the
2213 environment exists, then the value from the environment variable is
2216 o If both the SROM and the environment contain a MAC address, and
2217 both addresses are the same, this MAC address is used.
2219 o If both the SROM and the environment contain a MAC address, and the
2220 addresses differ, the value from the environment is used and a
2223 o If neither SROM nor the environment contain a MAC address, an error
2230 The "boot" commands of this monitor operate on "image" files which
2231 can be basicly anything, preceeded by a special header; see the
2232 definitions in include/image.h for details; basicly, the header
2233 defines the following image properties:
2235 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2236 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2237 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2238 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2239 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2240 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2241 Currently supported: PowerPC).
2242 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2243 Currently supported: uncompressed, gzip).
2249 The header is marked by a special Magic Number, and both the header
2250 and the data portions of the image are secured against corruption by
2257 Although U-Boot should support any OS or standalone application
2258 easily, Linux has always been in the focus during the design of
2261 U-Boot includes many features that so far have been part of some
2262 special "boot loader" code within the Linux kernel. Also, any
2263 "initrd" images to be used are no longer part of one big Linux image;
2264 instead, kernel and "initrd" are separate images. This implementation
2265 serves serveral purposes:
2267 - the same features can be used for other OS or standalone
2268 applications (for instance: using compressed images to reduce the
2269 Flash memory footprint)
2271 - it becomes much easier to port new Linux kernel versions because
2272 lots of low-level, hardware dependend stuff are done by U-Boot
2274 - the same Linux kernel image can now be used with different "initrd"
2275 images; of course this also means that different kernel images can
2276 be run with the same "initrd". This makes testing easier (you don't
2277 have to build a new "zImage.initrd" Linux image when you just
2278 change a file in your "initrd"). Also, a field-upgrade of the
2279 software is easier now.
2285 Porting Linux to U-Boot based systems:
2286 ---------------------------------------
2288 U-Boot cannot save you from doing all the necessary modifications to
2289 configure the Linux device drivers for use with your target hardware
2290 (no, we don't intend to provide a full virtual machine interface to
2293 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2295 Just make sure your machine specific header file (for instance
2296 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2297 Information structure as we define in include/u-boot.h, and make
2298 sure that your definition of IMAP_ADDR uses the same value as your
2299 U-Boot configuration in CFG_IMMR.
2302 Configuring the Linux kernel:
2303 -----------------------------
2305 No specific requirements for U-Boot. Make sure you have some root
2306 device (initial ramdisk, NFS) for your target system.
2309 Building a Linux Image:
2310 -----------------------
2312 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2313 not used. If you use recent kernel source, a new build target
2314 "uImage" will exist which automatically builds an image usable by
2315 U-Boot. Most older kernels also have support for a "pImage" target,
2316 which was introduced for our predecessor project PPCBoot and uses a
2317 100% compatible format.
2326 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2327 encapsulate a compressed Linux kernel image with header information,
2328 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2330 * build a standard "vmlinux" kernel image (in ELF binary format):
2332 * convert the kernel into a raw binary image:
2334 ${CROSS_COMPILE}-objcopy -O binary \
2335 -R .note -R .comment \
2336 -S vmlinux linux.bin
2338 * compress the binary image:
2342 * package compressed binary image for U-Boot:
2344 mkimage -A ppc -O linux -T kernel -C gzip \
2345 -a 0 -e 0 -n "Linux Kernel Image" \
2346 -d linux.bin.gz uImage
2349 The "mkimage" tool can also be used to create ramdisk images for use
2350 with U-Boot, either separated from the Linux kernel image, or
2351 combined into one file. "mkimage" encapsulates the images with a 64
2352 byte header containing information about target architecture,
2353 operating system, image type, compression method, entry points, time
2354 stamp, CRC32 checksums, etc.
2356 "mkimage" can be called in two ways: to verify existing images and
2357 print the header information, or to build new images.
2359 In the first form (with "-l" option) mkimage lists the information
2360 contained in the header of an existing U-Boot image; this includes
2361 checksum verification:
2363 tools/mkimage -l image
2364 -l ==> list image header information
2366 The second form (with "-d" option) is used to build a U-Boot image
2367 from a "data file" which is used as image payload:
2369 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2370 -n name -d data_file image
2371 -A ==> set architecture to 'arch'
2372 -O ==> set operating system to 'os'
2373 -T ==> set image type to 'type'
2374 -C ==> set compression type 'comp'
2375 -a ==> set load address to 'addr' (hex)
2376 -e ==> set entry point to 'ep' (hex)
2377 -n ==> set image name to 'name'
2378 -d ==> use image data from 'datafile'
2380 Right now, all Linux kernels use the same load address (0x00000000),
2381 but the entry point address depends on the kernel version:
2383 - 2.2.x kernels have the entry point at 0x0000000C,
2384 - 2.3.x and later kernels have the entry point at 0x00000000.
2386 So a typical call to build a U-Boot image would read:
2388 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2389 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2390 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2391 > examples/uImage.TQM850L
2392 Image Name: 2.4.4 kernel for TQM850L
2393 Created: Wed Jul 19 02:34:59 2000
2394 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2395 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2396 Load Address: 0x00000000
2397 Entry Point: 0x00000000
2399 To verify the contents of the image (or check for corruption):
2401 -> tools/mkimage -l examples/uImage.TQM850L
2402 Image Name: 2.4.4 kernel for TQM850L
2403 Created: Wed Jul 19 02:34:59 2000
2404 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2405 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2406 Load Address: 0x00000000
2407 Entry Point: 0x00000000
2409 NOTE: for embedded systems where boot time is critical you can trade
2410 speed for memory and install an UNCOMPRESSED image instead: this
2411 needs more space in Flash, but boots much faster since it does not
2412 need to be uncompressed:
2414 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2415 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2416 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2417 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2418 > examples/uImage.TQM850L-uncompressed
2419 Image Name: 2.4.4 kernel for TQM850L
2420 Created: Wed Jul 19 02:34:59 2000
2421 Image Type: PowerPC Linux Kernel Image (uncompressed)
2422 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2423 Load Address: 0x00000000
2424 Entry Point: 0x00000000
2427 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2428 when your kernel is intended to use an initial ramdisk:
2430 -> tools/mkimage -n 'Simple Ramdisk Image' \
2431 > -A ppc -O linux -T ramdisk -C gzip \
2432 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2433 Image Name: Simple Ramdisk Image
2434 Created: Wed Jan 12 14:01:50 2000
2435 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2436 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2437 Load Address: 0x00000000
2438 Entry Point: 0x00000000
2441 Installing a Linux Image:
2442 -------------------------
2444 To downloading a U-Boot image over the serial (console) interface,
2445 you must convert the image to S-Record format:
2447 objcopy -I binary -O srec examples/image examples/image.srec
2449 The 'objcopy' does not understand the information in the U-Boot
2450 image header, so the resulting S-Record file will be relative to
2451 address 0x00000000. To load it to a given address, you need to
2452 specify the target address as 'offset' parameter with the 'loads'
2455 Example: install the image to address 0x40100000 (which on the
2456 TQM8xxL is in the first Flash bank):
2458 => erase 40100000 401FFFFF
2464 ## Ready for S-Record download ...
2465 ~>examples/image.srec
2466 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2468 15989 15990 15991 15992
2469 [file transfer complete]
2471 ## Start Addr = 0x00000000
2474 You can check the success of the download using the 'iminfo' command;
2475 this includes a checksum verification so you can be sure no data
2476 corruption happened:
2480 ## Checking Image at 40100000 ...
2481 Image Name: 2.2.13 for initrd on TQM850L
2482 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2483 Data Size: 335725 Bytes = 327 kB = 0 MB
2484 Load Address: 00000000
2485 Entry Point: 0000000c
2486 Verifying Checksum ... OK
2492 The "bootm" command is used to boot an application that is stored in
2493 memory (RAM or Flash). In case of a Linux kernel image, the contents
2494 of the "bootargs" environment variable is passed to the kernel as
2495 parameters. You can check and modify this variable using the
2496 "printenv" and "setenv" commands:
2499 => printenv bootargs
2500 bootargs=root=/dev/ram
2502 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2504 => printenv bootargs
2505 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2508 ## Booting Linux kernel at 40020000 ...
2509 Image Name: 2.2.13 for NFS on TQM850L
2510 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2511 Data Size: 381681 Bytes = 372 kB = 0 MB
2512 Load Address: 00000000
2513 Entry Point: 0000000c
2514 Verifying Checksum ... OK
2515 Uncompressing Kernel Image ... OK
2516 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
2517 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2518 time_init: decrementer frequency = 187500000/60
2519 Calibrating delay loop... 49.77 BogoMIPS
2520 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2523 If you want to boot a Linux kernel with initial ram disk, you pass
2524 the memory addreses of both the kernel and the initrd image (PPBCOOT
2525 format!) to the "bootm" command:
2527 => imi 40100000 40200000
2529 ## Checking Image at 40100000 ...
2530 Image Name: 2.2.13 for initrd on TQM850L
2531 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2532 Data Size: 335725 Bytes = 327 kB = 0 MB
2533 Load Address: 00000000
2534 Entry Point: 0000000c
2535 Verifying Checksum ... OK
2537 ## Checking Image at 40200000 ...
2538 Image Name: Simple Ramdisk Image
2539 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2540 Data Size: 566530 Bytes = 553 kB = 0 MB
2541 Load Address: 00000000
2542 Entry Point: 00000000
2543 Verifying Checksum ... OK
2545 => bootm 40100000 40200000
2546 ## Booting Linux kernel at 40100000 ...
2547 Image Name: 2.2.13 for initrd on TQM850L
2548 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2549 Data Size: 335725 Bytes = 327 kB = 0 MB
2550 Load Address: 00000000
2551 Entry Point: 0000000c
2552 Verifying Checksum ... OK
2553 Uncompressing Kernel Image ... OK
2554 ## Loading RAMDisk Image at 40200000 ...
2555 Image Name: Simple Ramdisk Image
2556 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2557 Data Size: 566530 Bytes = 553 kB = 0 MB
2558 Load Address: 00000000
2559 Entry Point: 00000000
2560 Verifying Checksum ... OK
2561 Loading Ramdisk ... OK
2562 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
2563 Boot arguments: root=/dev/ram
2564 time_init: decrementer frequency = 187500000/60
2565 Calibrating delay loop... 49.77 BogoMIPS
2567 RAMDISK: Compressed image found at block 0
2568 VFS: Mounted root (ext2 filesystem).
2572 More About U-Boot Image Types:
2573 ------------------------------
2575 U-Boot supports the following image types:
2577 "Standalone Programs" are directly runnable in the environment
2578 provided by U-Boot; it is expected that (if they behave
2579 well) you can continue to work in U-Boot after return from
2580 the Standalone Program.
2581 "OS Kernel Images" are usually images of some Embedded OS which
2582 will take over control completely. Usually these programs
2583 will install their own set of exception handlers, device
2584 drivers, set up the MMU, etc. - this means, that you cannot
2585 expect to re-enter U-Boot except by resetting the CPU.
2586 "RAMDisk Images" are more or less just data blocks, and their
2587 parameters (address, size) are passed to an OS kernel that is
2589 "Multi-File Images" contain several images, typically an OS
2590 (Linux) kernel image and one or more data images like
2591 RAMDisks. This construct is useful for instance when you want
2592 to boot over the network using BOOTP etc., where the boot
2593 server provides just a single image file, but you want to get
2594 for instance an OS kernel and a RAMDisk image.
2596 "Multi-File Images" start with a list of image sizes, each
2597 image size (in bytes) specified by an "uint32_t" in network
2598 byte order. This list is terminated by an "(uint32_t)0".
2599 Immediately after the terminating 0 follow the images, one by
2600 one, all aligned on "uint32_t" boundaries (size rounded up to
2601 a multiple of 4 bytes).
2603 "Firmware Images" are binary images containing firmware (like
2604 U-Boot or FPGA images) which usually will be programmed to
2607 "Script files" are command sequences that will be executed by
2608 U-Boot's command interpreter; this feature is especially
2609 useful when you configure U-Boot to use a real shell (hush)
2610 as command interpreter.
2616 One of the features of U-Boot is that you can dynamically load and
2617 run "standalone" applications, which can use some resources of
2618 U-Boot like console I/O functions or interrupt services.
2620 Two simple examples are included with the sources:
2625 'examples/hello_world.c' contains a small "Hello World" Demo
2626 application; it is automatically compiled when you build U-Boot.
2627 It's configured to run at address 0x00040004, so you can play with it
2631 ## Ready for S-Record download ...
2632 ~>examples/hello_world.srec
2633 1 2 3 4 5 6 7 8 9 10 11 ...
2634 [file transfer complete]
2636 ## Start Addr = 0x00040004
2638 => go 40004 Hello World! This is a test.
2639 ## Starting application at 0x00040004 ...
2650 Hit any key to exit ...
2652 ## Application terminated, rc = 0x0
2654 Another example, which demonstrates how to register a CPM interrupt
2655 handler with the U-Boot code, can be found in 'examples/timer.c'.
2656 Here, a CPM timer is set up to generate an interrupt every second.
2657 The interrupt service routine is trivial, just printing a '.'
2658 character, but this is just a demo program. The application can be
2659 controlled by the following keys:
2661 ? - print current values og the CPM Timer registers
2662 b - enable interrupts and start timer
2663 e - stop timer and disable interrupts
2664 q - quit application
2667 ## Ready for S-Record download ...
2668 ~>examples/timer.srec
2669 1 2 3 4 5 6 7 8 9 10 11 ...
2670 [file transfer complete]
2672 ## Start Addr = 0x00040004
2675 ## Starting application at 0x00040004 ...
2678 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2681 [q, b, e, ?] Set interval 1000000 us
2684 [q, b, e, ?] ........
2685 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2688 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2691 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2694 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2696 [q, b, e, ?] ...Stopping timer
2698 [q, b, e, ?] ## Application terminated, rc = 0x0
2704 Over time, many people have reported problems when trying to used the
2705 "minicom" terminal emulation program for serial download. I (wd)
2706 consider minicom to be broken, and recommend not to use it. Under
2707 Unix, I recommend to use C-Kermit for general purpose use (and
2708 especially for kermit binary protocol download ("loadb" command), and
2709 use "cu" for S-Record download ("loads" command).
2711 Nevertheless, if you absolutely want to use it try adding this
2712 configuration to your "File transfer protocols" section:
2714 Name Program Name U/D FullScr IO-Red. Multi
2715 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2716 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2722 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2723 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2725 Building requires a cross environment; it is known to work on
2726 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2727 need gmake since the Makefiles are not compatible with BSD make).
2728 Note that the cross-powerpc package does not install include files;
2729 attempting to build U-Boot will fail because <machine/ansi.h> is
2730 missing. This file has to be installed and patched manually:
2732 # cd /usr/pkg/cross/powerpc-netbsd/include
2734 # ln -s powerpc machine
2735 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2736 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2738 Native builds *don't* work due to incompatibilities between native
2739 and U-Boot include files.
2741 Booting assumes that (the first part of) the image booted is a
2742 stage-2 loader which in turn loads and then invokes the kernel
2743 proper. Loader sources will eventually appear in the NetBSD source
2744 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2745 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2749 Implementation Internals:
2750 =========================
2752 The following is not intended to be a complete description of every
2753 implementation detail. However, it should help to understand the
2754 inner workings of U-Boot and make it easier to port it to custom
2758 Initial Stack, Global Data:
2759 ---------------------------
2761 The implementation of U-Boot is complicated by the fact that U-Boot
2762 starts running out of ROM (flash memory), usually without access to
2763 system RAM (because the memory controller is not initialized yet).
2764 This means that we don't have writable Data or BSS segments, and BSS
2765 is not initialized as zero. To be able to get a C environment working
2766 at all, we have to allocate at least a minimal stack. Implementation
2767 options for this are defined and restricted by the CPU used: Some CPU
2768 models provide on-chip memory (like the IMMR area on MPC8xx and
2769 MPC826x processors), on others (parts of) the data cache can be
2770 locked as (mis-) used as memory, etc.
2772 Chris Hallinan posted a good summy of these issues to the
2773 u-boot-users mailing list:
2775 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2776 From: "Chris Hallinan" <clh@net1plus.com>
2777 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2780 Correct me if I'm wrong, folks, but the way I understand it
2781 is this: Using DCACHE as initial RAM for Stack, etc, does not
2782 require any physical RAM backing up the cache. The cleverness
2783 is that the cache is being used as a temporary supply of
2784 necessary storage before the SDRAM controller is setup. It's
2785 beyond the scope of this list to expain the details, but you
2786 can see how this works by studying the cache architecture and
2787 operation in the architecture and processor-specific manuals.
2789 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2790 is another option for the system designer to use as an
2791 initial stack/ram area prior to SDRAM being available. Either
2792 option should work for you. Using CS 4 should be fine if your
2793 board designers haven't used it for something that would
2794 cause you grief during the initial boot! It is frequently not
2797 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2798 with your processor/board/system design. The default value
2799 you will find in any recent u-boot distribution in
2800 Walnut405.h should work for you. I'd set it to a value larger
2801 than your SDRAM module. If you have a 64MB SDRAM module, set
2802 it above 400_0000. Just make sure your board has no resources
2803 that are supposed to respond to that address! That code in
2804 start.S has been around a while and should work as is when
2805 you get the config right.
2810 It is essential to remember this, since it has some impact on the C
2811 code for the initialization procedures:
2813 * Initialized global data (data segment) is read-only. Do not attempt
2816 * Do not use any unitialized global data (or implicitely initialized
2817 as zero data - BSS segment) at all - this is undefined, initiali-
2818 zation is performed later (when relocationg to RAM).
2820 * Stack space is very limited. Avoid big data buffers or things like
2823 Having only the stack as writable memory limits means we cannot use
2824 normal global data to share information beween the code. But it
2825 turned out that the implementation of U-Boot can be greatly
2826 simplified by making a global data structure (gd_t) available to all
2827 functions. We could pass a pointer to this data as argument to _all_
2828 functions, but this would bloat the code. Instead we use a feature of
2829 the GCC compiler (Global Register Variables) to share the data: we
2830 place a pointer (gd) to the global data into a register which we
2831 reserve for this purpose.
2833 When chosing a register for such a purpose we are restricted by the
2834 relevant (E)ABI specifications for the current architecture, and by
2835 GCC's implementation.
2837 For PowerPC, the following registers have specific use:
2840 R3-R4: parameter passing and return values
2841 R5-R10: parameter passing
2842 R13: small data area pointer
2846 (U-Boot also uses R14 as internal GOT pointer.)
2848 ==> U-Boot will use R29 to hold a pointer to the global data
2850 Note: on PPC, we could use a static initializer (since the
2851 address of the global data structure is known at compile time),
2852 but it turned out that reserving a register results in somewhat
2853 smaller code - although the code savings are not that big (on
2854 average for all boards 752 bytes for the whole U-Boot image,
2855 624 text + 127 data).
2857 On ARM, the following registers are used:
2859 R0: function argument word/integer result
2860 R1-R3: function argument word
2862 R10: stack limit (used only if stack checking if enabled)
2863 R11: argument (frame) pointer
2864 R12: temporary workspace
2867 R15: program counter
2869 ==> U-Boot will use R8 to hold a pointer to the global data
2875 U-Boot runs in system state and uses physical addresses, i.e. the
2876 MMU is not used either for address mapping nor for memory protection.
2878 The available memory is mapped to fixed addresses using the memory
2879 controller. In this process, a contiguous block is formed for each
2880 memory type (Flash, SDRAM, SRAM), even when it consists of several
2881 physical memory banks.
2883 U-Boot is installed in the first 128 kB of the first Flash bank (on
2884 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2885 booting and sizing and initializing DRAM, the code relocates itself
2886 to the upper end of DRAM. Immediately below the U-Boot code some
2887 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2888 configuration setting]. Below that, a structure with global Board
2889 Info data is placed, followed by the stack (growing downward).
2891 Additionally, some exception handler code is copied to the low 8 kB
2892 of DRAM (0x00000000 ... 0x00001FFF).
2894 So a typical memory configuration with 16 MB of DRAM could look like
2897 0x0000 0000 Exception Vector code
2900 0x0000 2000 Free for Application Use
2906 0x00FB FF20 Monitor Stack (Growing downward)
2907 0x00FB FFAC Board Info Data and permanent copy of global data
2908 0x00FC 0000 Malloc Arena
2911 0x00FE 0000 RAM Copy of Monitor Code
2912 ... eventually: LCD or video framebuffer
2913 ... eventually: pRAM (Protected RAM - unchanged by reset)
2914 0x00FF FFFF [End of RAM]
2917 System Initialization:
2918 ----------------------
2920 In the reset configuration, U-Boot starts at the reset entry point
2921 (on most PowerPC systens at address 0x00000100). Because of the reset
2922 configuration for CS0# this is a mirror of the onboard Flash memory.
2923 To be able to re-map memory U-Boot then jumps to it's link address.
2924 To be able to implement the initialization code in C, a (small!)
2925 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2926 which provide such a feature like MPC8xx or MPC8260), or in a locked
2927 part of the data cache. After that, U-Boot initializes the CPU core,
2928 the caches and the SIU.
2930 Next, all (potentially) available memory banks are mapped using a
2931 preliminary mapping. For example, we put them on 512 MB boundaries
2932 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2933 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2934 programmed for SDRAM access. Using the temporary configuration, a
2935 simple memory test is run that determines the size of the SDRAM
2938 When there is more than one SDRAM bank, and the banks are of
2939 different size, the larger is mapped first. For equal size, the first
2940 bank (CS2#) is mapped first. The first mapping is always for address
2941 0x00000000, with any additional banks following immediately to create
2942 contiguous memory starting from 0.
2944 Then, the monitor installs itself at the upper end of the SDRAM area
2945 and allocates memory for use by malloc() and for the global Board
2946 Info data; also, the exception vector code is copied to the low RAM
2947 pages, and the final stack is set up.
2949 Only after this relocation will you have a "normal" C environment;
2950 until that you are restricted in several ways, mostly because you are
2951 running from ROM, and because the code will have to be relocated to a
2955 U-Boot Porting Guide:
2956 ----------------------
2958 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2962 int main (int argc, char *argv[])
2964 sighandler_t no_more_time;
2966 signal (SIGALRM, no_more_time);
2967 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2969 if (available_money > available_manpower) {
2970 pay consultant to port U-Boot;
2974 Download latest U-Boot source;
2976 Subscribe to u-boot-users mailing list;
2979 email ("Hi, I am new to U-Boot, how do I get started?");
2983 Read the README file in the top level directory;
2984 Read http://www.denx.de/re/DPLG.html
2985 Read the source, Luke;
2988 if (available_money > toLocalCurrency ($2500)) {
2991 Add a lot of aggravation and time;
2994 Create your own board support subdirectory;
2996 Create your own board config file;
3000 Add / modify source code;
3004 email ("Hi, I am having problems...");
3006 Send patch file to Wolfgang;
3011 void no_more_time (int sig)
3020 All contributions to U-Boot should conform to the Linux kernel
3021 coding style; see the file "Documentation/CodingStyle" in your Linux
3022 kernel source directory.
3024 Please note that U-Boot is implemented in C (and to some small parts
3025 in Assembler); no C++ is used, so please do not use C++ style
3026 comments (//) in your code.
3028 Submissions which do not conform to the standards may be returned
3029 with a request to reformat the changes.
3035 Since the number of patches for U-Boot is growing, we need to
3036 establish some rules. Submissions which do not conform to these rules
3037 may be rejected, even when they contain important and valuable stuff.
3040 When you send a patch, please include the following information with
3043 * For bug fixes: a description of the bug and how your patch fixes
3044 this bug. Please try to include a way of demonstrating that the
3045 patch actually fixes something.
3047 * For new features: a description of the feature and your
3050 * A CHANGELOG entry as plaintext (separate from the patch)
3052 * For major contributions, your entry to the CREDITS file
3054 * When you add support for a new board, don't forget to add this
3055 board to the MAKEALL script, too.
3057 * If your patch adds new configuration options, don't forget to
3058 document these in the README file.
3060 * The patch itself. If you are accessing the CVS repository use "cvs
3061 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3062 version of diff does not support these options, then get the latest
3063 version of GNU diff.
3065 The current directory when running this command shall be the top
3066 level directory of the U-Boot source tree, or it's parent directory
3067 (i. e. please make sure that your patch includes sufficient
3068 directory information for the affected files).
3070 We accept patches as plain text, MIME attachments or as uuencoded
3073 * If one logical set of modifications affects or creates several
3074 files, all these changes shall be submitted in a SINGLE patch file.
3076 * Changesets that contain different, unrelated modifications shall be
3077 submitted as SEPARATE patches, one patch per changeset.
3082 * Before sending the patch, run the MAKEALL script on your patched
3083 source tree and make sure that no errors or warnings are reported
3084 for any of the boards.
3086 * Keep your modifications to the necessary minimum: A patch
3087 containing several unrelated changes or arbitrary reformats will be
3088 returned with a request to re-formatting / split it.
3090 * If you modify existing code, make sure that your new code does not
3091 add to the memory footprint of the code ;-) Small is beautiful!
3092 When adding new features, these should compile conditionally only
3093 (using #ifdef), and the resulting code with the new feature
3094 disabled must not need more memory than the old code without your
projects / people / ms / u-boot.git / blob