2 # (C) Copyright 2000 - 2005
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, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - libfdt Library files to support flattened device trees
168 - net Networking code
169 - post Power On Self Test
170 - rtc Real Time Clock drivers
171 - tools Tools to build S-Record or U-Boot images, etc.
173 Software Configuration:
174 =======================
176 Configuration is usually done using C preprocessor defines; the
177 rationale behind that is to avoid dead code whenever possible.
179 There are two classes of configuration variables:
181 * Configuration _OPTIONS_:
182 These are selectable by the user and have names beginning with
185 * Configuration _SETTINGS_:
186 These depend on the hardware etc. and should not be meddled with if
187 you don't know what you're doing; they have names beginning with
190 Later we will add a configuration tool - probably similar to or even
191 identical to what's used for the Linux kernel. Right now, we have to
192 do the configuration by hand, which means creating some symbolic
193 links and editing some configuration files. We use the TQM8xxL boards
197 Selection of Processor Architecture and Board Type:
198 ---------------------------------------------------
200 For all supported boards there are ready-to-use default
201 configurations available; just type "make <board_name>_config".
203 Example: For a TQM823L module type:
208 For the Cogent platform, you need to specify the cpu type as well;
209 e.g. "make cogent_mpc8xx_config". And also configure the cogent
210 directory according to the instructions in cogent/README.
213 Configuration Options:
214 ----------------------
216 Configuration depends on the combination of board and CPU type; all
217 such information is kept in a configuration file
218 "include/configs/<board_name>.h".
220 Example: For a TQM823L module, all configuration settings are in
221 "include/configs/TQM823L.h".
224 Many of the options are named exactly as the corresponding Linux
225 kernel configuration options. The intention is to make it easier to
226 build a config tool - later.
229 The following options need to be configured:
231 - CPU Type: Define exactly one of
235 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
238 or CONFIG_MPC824X, CONFIG_MPC8260
255 MicroBlaze based CPUs:
256 ----------------------
260 ----------------------
264 ----------------------
267 - Board Type: Define exactly one of
269 PowerPC based boards:
270 ---------------------
272 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
273 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
274 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
275 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
276 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
277 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
278 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
279 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
280 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
281 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
282 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
283 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
284 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
285 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
286 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
287 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
288 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
289 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
290 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
291 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
292 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
293 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
294 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
295 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
296 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
297 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
298 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
299 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
300 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
301 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
302 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
303 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
304 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
305 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
306 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
307 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
308 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
309 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
314 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
315 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
316 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
317 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
318 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
319 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
320 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
321 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
324 MicroBlaze based boards:
325 ------------------------
330 ------------------------
332 CONFIG_PCI5441 CONFIG_PK1C20
333 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
340 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
341 Define exactly one of
345 - CPU Module Type: (if CONFIG_COGENT is defined)
346 Define exactly one of
348 --- FIXME --- not tested yet:
349 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
350 CONFIG_CMA287_23, CONFIG_CMA287_50
352 - Motherboard Type: (if CONFIG_COGENT is defined)
353 Define exactly one of
354 CONFIG_CMA101, CONFIG_CMA102
356 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
357 Define one or more of
360 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
361 Define one or more of
362 CONFIG_LCD_HEARTBEAT - update a character position on
363 the lcd display every second with
366 - Board flavour: (if CONFIG_MPC8260ADS is defined)
369 CFG_8260ADS - original MPC8260ADS
370 CFG_8266ADS - MPC8266ADS
371 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
372 CFG_8272ADS - MPC8272ADS
374 - MPC824X Family Member (if CONFIG_MPC824X is defined)
375 Define exactly one of
376 CONFIG_MPC8240, CONFIG_MPC8245
378 - 8xx CPU Options: (if using an MPC8xx cpu)
379 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
380 get_gclk_freq() cannot work
381 e.g. if there is no 32KHz
382 reference PIT/RTC clock
383 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
386 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
389 CONFIG_8xx_CPUCLK_DEFAULT
390 See doc/README.MPC866
394 Define this to measure the actual CPU clock instead
395 of relying on the correctness of the configured
396 values. Mostly useful for board bringup to make sure
397 the PLL is locked at the intended frequency. Note
398 that this requires a (stable) reference clock (32 kHz
399 RTC clock or CFG_8XX_XIN)
401 - Intel Monahans options:
402 CFG_MONAHANS_RUN_MODE_OSC_RATIO
404 Defines the Monahans run mode to oscillator
405 ratio. Valid values are 8, 16, 24, 31. The core
406 frequency is this value multiplied by 13 MHz.
408 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
410 Defines the Monahans turbo mode to oscillator
411 ratio. Valid values are 1 (default if undefined) and
412 2. The core frequency as calculated above is multiplied
415 - Linux Kernel Interface:
418 U-Boot stores all clock information in Hz
419 internally. For binary compatibility with older Linux
420 kernels (which expect the clocks passed in the
421 bd_info data to be in MHz) the environment variable
422 "clocks_in_mhz" can be defined so that U-Boot
423 converts clock data to MHZ before passing it to the
425 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
426 "clocks_in_mhz=1" is automatically included in the
429 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
431 When transfering memsize parameter to linux, some versions
432 expect it to be in bytes, others in MB.
433 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
435 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
437 New kernel versions are expecting firmware settings to be
438 passed using flattened device trees (based on open firmware
442 * New libfdt-based support
443 * Adds the "fdt" command
444 * The bootm command does _not_ modify the fdt
447 * Deprecated, see CONFIG_OF_LIBFDT
448 * Original ft_build.c-based support
449 * Automatically modifies the dft as part of the bootm command
450 * The environment variable "disable_of", when set,
451 disables this functionality.
453 CONFIG_OF_FLAT_TREE_MAX_SIZE
455 The maximum size of the constructed OF tree.
457 OF_CPU - The proper name of the cpus node.
458 OF_SOC - The proper name of the soc node.
459 OF_TBCLK - The timebase frequency.
460 OF_STDOUT_PATH - The path to the console device
464 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
465 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
466 will have a copy of the bd_t. Space should be
467 pre-allocated in the dts for the bd_t.
469 CONFIG_OF_HAS_UBOOT_ENV
471 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
472 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
473 will have a copy of u-boot's environment variables
475 CONFIG_OF_BOARD_SETUP
477 Board code has addition modification that it wants to make
478 to the flat device tree before handing it off to the kernel
482 This define fills in the correct boot cpu in the boot
483 param header, the default value is zero if undefined.
488 Define this if you want support for Amba PrimeCell PL010 UARTs.
492 Define this if you want support for Amba PrimeCell PL011 UARTs.
496 If you have Amba PrimeCell PL011 UARTs, set this variable to
497 the clock speed of the UARTs.
501 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
502 define this to a list of base addresses for each (supported)
503 port. See e.g. include/configs/versatile.h
507 Depending on board, define exactly one serial port
508 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
509 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
510 console by defining CONFIG_8xx_CONS_NONE
512 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
513 port routines must be defined elsewhere
514 (i.e. serial_init(), serial_getc(), ...)
517 Enables console device for a color framebuffer. Needs following
518 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
519 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
521 VIDEO_HW_RECTFILL graphic chip supports
524 VIDEO_HW_BITBLT graphic chip supports
525 bit-blit (cf. smiLynxEM)
526 VIDEO_VISIBLE_COLS visible pixel columns
528 VIDEO_VISIBLE_ROWS visible pixel rows
529 VIDEO_PIXEL_SIZE bytes per pixel
530 VIDEO_DATA_FORMAT graphic data format
531 (0-5, cf. cfb_console.c)
532 VIDEO_FB_ADRS framebuffer address
533 VIDEO_KBD_INIT_FCT keyboard int fct
534 (i.e. i8042_kbd_init())
535 VIDEO_TSTC_FCT test char fct
537 VIDEO_GETC_FCT get char fct
539 CONFIG_CONSOLE_CURSOR cursor drawing on/off
540 (requires blink timer
542 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
543 CONFIG_CONSOLE_TIME display time/date info in
545 (requires CFG_CMD_DATE)
546 CONFIG_VIDEO_LOGO display Linux logo in
548 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
549 linux_logo.h for logo.
550 Requires CONFIG_VIDEO_LOGO
551 CONFIG_CONSOLE_EXTRA_INFO
552 addional board info beside
555 When CONFIG_CFB_CONSOLE is defined, video console is
556 default i/o. Serial console can be forced with
557 environment 'console=serial'.
559 When CONFIG_SILENT_CONSOLE is defined, all console
560 messages (by U-Boot and Linux!) can be silenced with
561 the "silent" environment variable. See
562 doc/README.silent for more information.
565 CONFIG_BAUDRATE - in bps
566 Select one of the baudrates listed in
567 CFG_BAUDRATE_TABLE, see below.
568 CFG_BRGCLK_PRESCALE, baudrate prescale
570 - Interrupt driven serial port input:
571 CONFIG_SERIAL_SOFTWARE_FIFO
574 Use an interrupt handler for receiving data on the
575 serial port. It also enables using hardware handshake
576 (RTS/CTS) and UART's built-in FIFO. Set the number of
577 bytes the interrupt driven input buffer should have.
579 Leave undefined to disable this feature, including
580 disable the buffer and hardware handshake.
582 - Console UART Number:
586 If defined internal UART1 (and not UART0) is used
587 as default U-Boot console.
589 - Boot Delay: CONFIG_BOOTDELAY - in seconds
590 Delay before automatically booting the default image;
591 set to -1 to disable autoboot.
593 See doc/README.autoboot for these options that
594 work with CONFIG_BOOTDELAY. None are required.
595 CONFIG_BOOT_RETRY_TIME
596 CONFIG_BOOT_RETRY_MIN
597 CONFIG_AUTOBOOT_KEYED
598 CONFIG_AUTOBOOT_PROMPT
599 CONFIG_AUTOBOOT_DELAY_STR
600 CONFIG_AUTOBOOT_STOP_STR
601 CONFIG_AUTOBOOT_DELAY_STR2
602 CONFIG_AUTOBOOT_STOP_STR2
603 CONFIG_ZERO_BOOTDELAY_CHECK
604 CONFIG_RESET_TO_RETRY
608 Only needed when CONFIG_BOOTDELAY is enabled;
609 define a command string that is automatically executed
610 when no character is read on the console interface
611 within "Boot Delay" after reset.
614 This can be used to pass arguments to the bootm
615 command. The value of CONFIG_BOOTARGS goes into the
616 environment value "bootargs".
618 CONFIG_RAMBOOT and CONFIG_NFSBOOT
619 The value of these goes into the environment as
620 "ramboot" and "nfsboot" respectively, and can be used
621 as a convenience, when switching between booting from
627 When this option is #defined, the existence of the
628 environment variable "preboot" will be checked
629 immediately before starting the CONFIG_BOOTDELAY
630 countdown and/or running the auto-boot command resp.
631 entering interactive mode.
633 This feature is especially useful when "preboot" is
634 automatically generated or modified. For an example
635 see the LWMON board specific code: here "preboot" is
636 modified when the user holds down a certain
637 combination of keys on the (special) keyboard when
640 - Serial Download Echo Mode:
642 If defined to 1, all characters received during a
643 serial download (using the "loads" command) are
644 echoed back. This might be needed by some terminal
645 emulations (like "cu"), but may as well just take
646 time on others. This setting #define's the initial
647 value of the "loads_echo" environment variable.
649 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
651 Select one of the baudrates listed in
652 CFG_BAUDRATE_TABLE, see below.
656 Most monitor functions can be selected (or
657 de-selected) by adjusting the definition of
658 CONFIG_COMMANDS; to select individual functions,
659 #define CONFIG_COMMANDS by "OR"ing any of the
662 #define enables commands:
663 -------------------------
664 CFG_CMD_ASKENV * ask for env variable
665 CFG_CMD_AUTOSCRIPT Autoscript Support
667 CFG_CMD_BEDBUG * Include BedBug Debugger
668 CFG_CMD_BMP * BMP support
669 CFG_CMD_BSP * Board specific commands
671 CFG_CMD_CACHE * icache, dcache
672 CFG_CMD_CONSOLE coninfo
673 CFG_CMD_DATE * support for RTC, date/time...
674 CFG_CMD_DHCP * DHCP support
675 CFG_CMD_DIAG * Diagnostics
676 CFG_CMD_DOC * Disk-On-Chip Support
677 CFG_CMD_DTT * Digital Therm and Thermostat
678 CFG_CMD_ECHO echo arguments
679 CFG_CMD_EEPROM * EEPROM read/write support
680 CFG_CMD_ELF * bootelf, bootvx
682 CFG_CMD_FDC * Floppy Disk Support
683 CFG_CMD_FAT * FAT partition support
684 CFG_CMD_FDOS * Dos diskette Support
685 CFG_CMD_FLASH flinfo, erase, protect
686 CFG_CMD_FPGA FPGA device initialization support
687 CFG_CMD_HWFLOW * RTS/CTS hw flow control
688 CFG_CMD_I2C * I2C serial bus support
689 CFG_CMD_IDE * IDE harddisk support
691 CFG_CMD_IMLS List all found images
692 CFG_CMD_IMMAP * IMMR dump support
693 CFG_CMD_IRQ * irqinfo
694 CFG_CMD_ITEST Integer/string test of 2 values
695 CFG_CMD_JFFS2 * JFFS2 Support
699 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
701 CFG_CMD_MISC Misc functions like sleep etc
702 CFG_CMD_MMC * MMC memory mapped support
703 CFG_CMD_MII * MII utility commands
704 CFG_CMD_NAND * NAND support
705 CFG_CMD_NET bootp, tftpboot, rarpboot
706 CFG_CMD_PCI * pciinfo
707 CFG_CMD_PCMCIA * PCMCIA support
708 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
709 CFG_CMD_PORTIO * Port I/O
710 CFG_CMD_REGINFO * Register dump
711 CFG_CMD_RUN run command in env variable
712 CFG_CMD_SAVES * save S record dump
713 CFG_CMD_SCSI * SCSI Support
714 CFG_CMD_SDRAM * print SDRAM configuration information
715 (requires CFG_CMD_I2C)
716 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
717 CFG_CMD_SPI * SPI serial bus support
718 CFG_CMD_USB * USB support
719 CFG_CMD_VFD * VFD support (TRAB)
720 CFG_CMD_BSP * Board SPecific functions
721 CFG_CMD_CDP * Cisco Discover Protocol support
722 CFG_CMD_FSL * Microblaze FSL support
723 -----------------------------------------------
726 CONFIG_CMD_DFL Default configuration; at the moment
727 this is includes all commands, except
728 the ones marked with "*" in the list
731 If you don't define CONFIG_COMMANDS it defaults to
732 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
733 override the default settings in the respective
736 EXAMPLE: If you want all functions except of network
737 support you can write:
739 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
742 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
744 Note: Don't enable the "icache" and "dcache" commands
745 (configuration option CFG_CMD_CACHE) unless you know
746 what you (and your U-Boot users) are doing. Data
747 cache cannot be enabled on systems like the 8xx or
748 8260 (where accesses to the IMMR region must be
749 uncached), and it cannot be disabled on all other
750 systems where we (mis-) use the data cache to hold an
751 initial stack and some data.
754 XXX - this list needs to get updated!
758 If this variable is defined, it enables watchdog
759 support. There must be support in the platform specific
760 code for a watchdog. For the 8xx and 8260 CPUs, the
761 SIU Watchdog feature is enabled in the SYPCR
765 CONFIG_VERSION_VARIABLE
766 If this variable is defined, an environment variable
767 named "ver" is created by U-Boot showing the U-Boot
768 version as printed by the "version" command.
769 This variable is readonly.
773 When CFG_CMD_DATE is selected, the type of the RTC
774 has to be selected, too. Define exactly one of the
777 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
778 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
779 CONFIG_RTC_MC146818 - use MC146818 RTC
780 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
781 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
782 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
783 CONFIG_RTC_DS164x - use Dallas DS164x RTC
784 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
786 Note that if the RTC uses I2C, then the I2C interface
787 must also be configured. See I2C Support, below.
791 When CONFIG_TIMESTAMP is selected, the timestamp
792 (date and time) of an image is printed by image
793 commands like bootm or iminfo. This option is
794 automatically enabled when you select CFG_CMD_DATE .
797 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
798 and/or CONFIG_ISO_PARTITION
800 If IDE or SCSI support is enabled (CFG_CMD_IDE or
801 CFG_CMD_SCSI) you must configure support for at least
802 one partition type as well.
805 CONFIG_IDE_RESET_ROUTINE - this is defined in several
806 board configurations files but used nowhere!
808 CONFIG_IDE_RESET - is this is defined, IDE Reset will
809 be performed by calling the function
810 ide_set_reset(int reset)
811 which has to be defined in a board specific file
816 Set this to enable ATAPI support.
821 Set this to enable support for disks larger than 137GB
822 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
823 Whithout these , LBA48 support uses 32bit variables and will 'only'
824 support disks up to 2.1TB.
827 When enabled, makes the IDE subsystem use 64bit sector addresses.
831 At the moment only there is only support for the
832 SYM53C8XX SCSI controller; define
833 CONFIG_SCSI_SYM53C8XX to enable it.
835 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
836 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
837 CFG_SCSI_MAX_LUN] can be adjusted to define the
838 maximum numbers of LUNs, SCSI ID's and target
840 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
842 - NETWORK Support (PCI):
844 Support for Intel 8254x gigabit chips.
847 Support for Intel 82557/82559/82559ER chips.
848 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
849 write routine for first time initialisation.
852 Support for Digital 2114x chips.
853 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
854 modem chip initialisation (KS8761/QS6611).
857 Support for National dp83815 chips.
860 Support for National dp8382[01] gigabit chips.
862 - NETWORK Support (other):
864 CONFIG_DRIVER_LAN91C96
865 Support for SMSC's LAN91C96 chips.
868 Define this to hold the physical address
869 of the LAN91C96's I/O space
871 CONFIG_LAN91C96_USE_32_BIT
872 Define this to enable 32 bit addressing
874 CONFIG_DRIVER_SMC91111
875 Support for SMSC's LAN91C111 chip
878 Define this to hold the physical address
879 of the device (I/O space)
881 CONFIG_SMC_USE_32_BIT
882 Define this if data bus is 32 bits
884 CONFIG_SMC_USE_IOFUNCS
885 Define this to use i/o functions instead of macros
886 (some hardware wont work with macros)
889 At the moment only the UHCI host controller is
890 supported (PIP405, MIP405, MPC5200); define
891 CONFIG_USB_UHCI to enable it.
892 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
893 and define CONFIG_USB_STORAGE to enable the USB
896 Supported are USB Keyboards and USB Floppy drives
898 MPC5200 USB requires additional defines:
900 for 528 MHz Clock: 0x0001bbbb
902 for differential drivers: 0x00001000
903 for single ended drivers: 0x00005000
906 Define the below if you wish to use the USB console.
907 Once firmware is rebuilt from a serial console issue the
908 command "setenv stdin usbtty; setenv stdout usbtty" and
909 attach your usb cable. The Unix command "dmesg" should print
910 it has found a new device. The environment variable usbtty
911 can be set to gserial or cdc_acm to enable your device to
912 appear to a USB host as a Linux gserial device or a
913 Common Device Class Abstract Control Model serial device.
914 If you select usbtty = gserial you should be able to enumerate
916 # modprobe usbserial vendor=0xVendorID product=0xProductID
917 else if using cdc_acm, simply setting the environment
918 variable usbtty to be cdc_acm should suffice. The following
919 might be defined in YourBoardName.h
922 Define this to build a UDC device
925 Define this to have a tty type of device available to
926 talk to the UDC device
928 CFG_CONSOLE_IS_IN_ENV
929 Define this if you want stdin, stdout &/or stderr to
933 CFG_USB_EXTC_CLK 0xBLAH
934 Derive USB clock from external clock "blah"
935 - CFG_USB_EXTC_CLK 0x02
937 CFG_USB_BRG_CLK 0xBLAH
938 Derive USB clock from brgclk
939 - CFG_USB_BRG_CLK 0x04
941 If you have a USB-IF assigned VendorID then you may wish to
942 define your own vendor specific values either in BoardName.h
943 or directly in usbd_vendor_info.h. If you don't define
944 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
945 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
946 should pretend to be a Linux device to it's target host.
948 CONFIG_USBD_MANUFACTURER
949 Define this string as the name of your company for
950 - CONFIG_USBD_MANUFACTURER "my company"
952 CONFIG_USBD_PRODUCT_NAME
953 Define this string as the name of your product
954 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
957 Define this as your assigned Vendor ID from the USB
958 Implementors Forum. This *must* be a genuine Vendor ID
959 to avoid polluting the USB namespace.
960 - CONFIG_USBD_VENDORID 0xFFFF
962 CONFIG_USBD_PRODUCTID
963 Define this as the unique Product ID
965 - CONFIG_USBD_PRODUCTID 0xFFFF
969 The MMC controller on the Intel PXA is supported. To
970 enable this define CONFIG_MMC. The MMC can be
971 accessed from the boot prompt by mapping the device
972 to physical memory similar to flash. Command line is
973 enabled with CFG_CMD_MMC. The MMC driver also works with
974 the FAT fs. This is enabled with CFG_CMD_FAT.
976 - Journaling Flash filesystem support:
977 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
978 CONFIG_JFFS2_NAND_DEV
979 Define these for a default partition on a NAND device
981 CFG_JFFS2_FIRST_SECTOR,
982 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
983 Define these for a default partition on a NOR device
986 Define this to create an own partition. You have to provide a
987 function struct part_info* jffs2_part_info(int part_num)
989 If you define only one JFFS2 partition you may also want to
990 #define CFG_JFFS_SINGLE_PART 1
991 to disable the command chpart. This is the default when you
992 have not defined a custom partition
997 Define this to enable standard (PC-Style) keyboard
1001 Standard PC keyboard driver with US (is default) and
1002 GERMAN key layout (switch via environment 'keymap=de') support.
1003 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1004 for cfb_console. Supports cursor blinking.
1009 Define this to enable video support (for output to
1012 CONFIG_VIDEO_CT69000
1014 Enable Chips & Technologies 69000 Video chip
1016 CONFIG_VIDEO_SMI_LYNXEM
1017 Enable Silicon Motion SMI 712/710/810 Video chip. The
1018 video output is selected via environment 'videoout'
1019 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1022 For the CT69000 and SMI_LYNXEM drivers, videomode is
1023 selected via environment 'videomode'. Two diferent ways
1025 - "videomode=num" 'num' is a standard LiLo mode numbers.
1026 Following standard modes are supported (* is default):
1028 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1029 -------------+---------------------------------------------
1030 8 bits | 0x301* 0x303 0x305 0x161 0x307
1031 15 bits | 0x310 0x313 0x316 0x162 0x319
1032 16 bits | 0x311 0x314 0x317 0x163 0x31A
1033 24 bits | 0x312 0x315 0x318 ? 0x31B
1034 -------------+---------------------------------------------
1035 (i.e. setenv videomode 317; saveenv; reset;)
1037 - "videomode=bootargs" all the video parameters are parsed
1038 from the bootargs. (See drivers/videomodes.c)
1041 CONFIG_VIDEO_SED13806
1042 Enable Epson SED13806 driver. This driver supports 8bpp
1043 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1044 or CONFIG_VIDEO_SED13806_16BPP
1049 Define this to enable a custom keyboard support.
1050 This simply calls drv_keyboard_init() which must be
1051 defined in your board-specific files.
1052 The only board using this so far is RBC823.
1054 - LCD Support: CONFIG_LCD
1056 Define this to enable LCD support (for output to LCD
1057 display); also select one of the supported displays
1058 by defining one of these:
1060 CONFIG_NEC_NL6448AC33:
1062 NEC NL6448AC33-18. Active, color, single scan.
1064 CONFIG_NEC_NL6448BC20
1066 NEC NL6448BC20-08. 6.5", 640x480.
1067 Active, color, single scan.
1069 CONFIG_NEC_NL6448BC33_54
1071 NEC NL6448BC33-54. 10.4", 640x480.
1072 Active, color, single scan.
1076 Sharp 320x240. Active, color, single scan.
1077 It isn't 16x9, and I am not sure what it is.
1079 CONFIG_SHARP_LQ64D341
1081 Sharp LQ64D341 display, 640x480.
1082 Active, color, single scan.
1086 HLD1045 display, 640x480.
1087 Active, color, single scan.
1091 Optrex CBL50840-2 NF-FW 99 22 M5
1093 Hitachi LMG6912RPFC-00T
1097 320x240. Black & white.
1099 Normally display is black on white background; define
1100 CFG_WHITE_ON_BLACK to get it inverted.
1102 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1104 If this option is set, the environment is checked for
1105 a variable "splashimage". If found, the usual display
1106 of logo, copyright and system information on the LCD
1107 is suppressed and the BMP image at the address
1108 specified in "splashimage" is loaded instead. The
1109 console is redirected to the "nulldev", too. This
1110 allows for a "silent" boot where a splash screen is
1111 loaded very quickly after power-on.
1113 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1115 If this option is set, additionally to standard BMP
1116 images, gzipped BMP images can be displayed via the
1117 splashscreen support or the bmp command.
1119 - Compression support:
1122 If this option is set, support for bzip2 compressed
1123 images is included. If not, only uncompressed and gzip
1124 compressed images are supported.
1126 NOTE: the bzip2 algorithm requires a lot of RAM, so
1127 the malloc area (as defined by CFG_MALLOC_LEN) should
1133 The address of PHY on MII bus.
1135 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1137 The clock frequency of the MII bus
1141 If this option is set, support for speed/duplex
1142 detection of Gigabit PHY is included.
1144 CONFIG_PHY_RESET_DELAY
1146 Some PHY like Intel LXT971A need extra delay after
1147 reset before any MII register access is possible.
1148 For such PHY, set this option to the usec delay
1149 required. (minimum 300usec for LXT971A)
1151 CONFIG_PHY_CMD_DELAY (ppc4xx)
1153 Some PHY like Intel LXT971A need extra delay after
1154 command issued before MII status register can be read
1161 Define a default value for ethernet address to use
1162 for the respective ethernet interface, in case this
1163 is not determined automatically.
1168 Define a default value for the IP address to use for
1169 the default ethernet interface, in case this is not
1170 determined through e.g. bootp.
1172 - Server IP address:
1175 Defines a default value for theIP address of a TFTP
1176 server to contact when using the "tftboot" command.
1178 - BOOTP Recovery Mode:
1179 CONFIG_BOOTP_RANDOM_DELAY
1181 If you have many targets in a network that try to
1182 boot using BOOTP, you may want to avoid that all
1183 systems send out BOOTP requests at precisely the same
1184 moment (which would happen for instance at recovery
1185 from a power failure, when all systems will try to
1186 boot, thus flooding the BOOTP server. Defining
1187 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1188 inserted before sending out BOOTP requests. The
1189 following delays are insterted then:
1191 1st BOOTP request: delay 0 ... 1 sec
1192 2nd BOOTP request: delay 0 ... 2 sec
1193 3rd BOOTP request: delay 0 ... 4 sec
1195 BOOTP requests: delay 0 ... 8 sec
1197 - DHCP Advanced Options:
1200 You can fine tune the DHCP functionality by adding
1201 these flags to the CONFIG_BOOTP_MASK define:
1203 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1204 serverip from a DHCP server, it is possible that more
1205 than one DNS serverip is offered to the client.
1206 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1207 serverip will be stored in the additional environment
1208 variable "dnsip2". The first DNS serverip is always
1209 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1210 is added to the CONFIG_BOOTP_MASK.
1212 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1213 to do a dynamic update of a DNS server. To do this, they
1214 need the hostname of the DHCP requester.
1215 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1216 CONFIG_BOOTP_MASK, the content of the "hostname"
1217 environment variable is passed as option 12 to
1221 CONFIG_CDP_DEVICE_ID
1223 The device id used in CDP trigger frames.
1225 CONFIG_CDP_DEVICE_ID_PREFIX
1227 A two character string which is prefixed to the MAC address
1232 A printf format string which contains the ascii name of
1233 the port. Normally is set to "eth%d" which sets
1234 eth0 for the first ethernet, eth1 for the second etc.
1236 CONFIG_CDP_CAPABILITIES
1238 A 32bit integer which indicates the device capabilities;
1239 0x00000010 for a normal host which does not forwards.
1243 An ascii string containing the version of the software.
1247 An ascii string containing the name of the platform.
1251 A 32bit integer sent on the trigger.
1253 CONFIG_CDP_POWER_CONSUMPTION
1255 A 16bit integer containing the power consumption of the
1256 device in .1 of milliwatts.
1258 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1260 A byte containing the id of the VLAN.
1262 - Status LED: CONFIG_STATUS_LED
1264 Several configurations allow to display the current
1265 status using a LED. For instance, the LED will blink
1266 fast while running U-Boot code, stop blinking as
1267 soon as a reply to a BOOTP request was received, and
1268 start blinking slow once the Linux kernel is running
1269 (supported by a status LED driver in the Linux
1270 kernel). Defining CONFIG_STATUS_LED enables this
1273 - CAN Support: CONFIG_CAN_DRIVER
1275 Defining CONFIG_CAN_DRIVER enables CAN driver support
1276 on those systems that support this (optional)
1277 feature, like the TQM8xxL modules.
1279 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1281 These enable I2C serial bus commands. Defining either of
1282 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1283 include the appropriate I2C driver for the selected cpu.
1285 This will allow you to use i2c commands at the u-boot
1286 command line (as long as you set CFG_CMD_I2C in
1287 CONFIG_COMMANDS) and communicate with i2c based realtime
1288 clock chips. See common/cmd_i2c.c for a description of the
1289 command line interface.
1291 CONFIG_I2C_CMD_TREE is a recommended option that places
1292 all I2C commands under a single 'i2c' root command. The
1293 older 'imm', 'imd', 'iprobe' etc. commands are considered
1294 deprecated and may disappear in the future.
1296 CONFIG_HARD_I2C selects a hardware I2C controller.
1298 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1299 bit-banging) driver instead of CPM or similar hardware
1302 There are several other quantities that must also be
1303 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1305 In both cases you will need to define CFG_I2C_SPEED
1306 to be the frequency (in Hz) at which you wish your i2c bus
1307 to run and CFG_I2C_SLAVE to be the address of this node (ie
1308 the cpu's i2c node address).
1310 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1311 sets the cpu up as a master node and so its address should
1312 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1313 p.16-473). So, set CFG_I2C_SLAVE to 0.
1315 That's all that's required for CONFIG_HARD_I2C.
1317 If you use the software i2c interface (CONFIG_SOFT_I2C)
1318 then the following macros need to be defined (examples are
1319 from include/configs/lwmon.h):
1323 (Optional). Any commands necessary to enable the I2C
1324 controller or configure ports.
1326 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1330 (Only for MPC8260 CPU). The I/O port to use (the code
1331 assumes both bits are on the same port). Valid values
1332 are 0..3 for ports A..D.
1336 The code necessary to make the I2C data line active
1337 (driven). If the data line is open collector, this
1340 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1344 The code necessary to make the I2C data line tri-stated
1345 (inactive). If the data line is open collector, this
1348 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1352 Code that returns TRUE if the I2C data line is high,
1355 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1359 If <bit> is TRUE, sets the I2C data line high. If it
1360 is FALSE, it clears it (low).
1362 eg: #define I2C_SDA(bit) \
1363 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1364 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1368 If <bit> is TRUE, sets the I2C clock line high. If it
1369 is FALSE, it clears it (low).
1371 eg: #define I2C_SCL(bit) \
1372 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1373 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1377 This delay is invoked four times per clock cycle so this
1378 controls the rate of data transfer. The data rate thus
1379 is 1 / (I2C_DELAY * 4). Often defined to be something
1382 #define I2C_DELAY udelay(2)
1386 When a board is reset during an i2c bus transfer
1387 chips might think that the current transfer is still
1388 in progress. On some boards it is possible to access
1389 the i2c SCLK line directly, either by using the
1390 processor pin as a GPIO or by having a second pin
1391 connected to the bus. If this option is defined a
1392 custom i2c_init_board() routine in boards/xxx/board.c
1393 is run early in the boot sequence.
1395 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1397 This option enables configuration of bi_iic_fast[] flags
1398 in u-boot bd_info structure based on u-boot environment
1399 variable "i2cfast". (see also i2cfast)
1401 CONFIG_I2C_MULTI_BUS
1403 This option allows the use of multiple I2C buses, each of which
1404 must have a controller. At any point in time, only one bus is
1405 active. To switch to a different bus, use the 'i2c dev' command.
1406 Note that bus numbering is zero-based.
1410 This option specifies a list of I2C devices that will be skipped
1411 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1412 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1413 pairs. Otherwise, specify a 1D array of device addresses
1416 #undef CONFIG_I2C_MULTI_BUS
1417 #define CFG_I2C_NOPROBES {0x50,0x68}
1419 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1421 #define CONFIG_I2C_MULTI_BUS
1422 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1424 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1428 If defined, then this indicates the I2C bus number for DDR SPD.
1429 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1433 If defined, then this indicates the I2C bus number for the RTC.
1434 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1438 If defined, then this indicates the I2C bus number for the DTT.
1439 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1443 Define this option if you want to use Freescale's I2C driver in
1447 - SPI Support: CONFIG_SPI
1449 Enables SPI driver (so far only tested with
1450 SPI EEPROM, also an instance works with Crystal A/D and
1451 D/As on the SACSng board)
1455 Enables extended (16-bit) SPI EEPROM addressing.
1456 (symmetrical to CONFIG_I2C_X)
1460 Enables a software (bit-bang) SPI driver rather than
1461 using hardware support. This is a general purpose
1462 driver that only requires three general I/O port pins
1463 (two outputs, one input) to function. If this is
1464 defined, the board configuration must define several
1465 SPI configuration items (port pins to use, etc). For
1466 an example, see include/configs/sacsng.h.
1468 - FPGA Support: CONFIG_FPGA_COUNT
1470 Specify the number of FPGA devices to support.
1474 Used to specify the types of FPGA devices. For example,
1475 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1477 CFG_FPGA_PROG_FEEDBACK
1479 Enable printing of hash marks during FPGA configuration.
1483 Enable checks on FPGA configuration interface busy
1484 status by the configuration function. This option
1485 will require a board or device specific function to
1490 If defined, a function that provides delays in the FPGA
1491 configuration driver.
1493 CFG_FPGA_CHECK_CTRLC
1494 Allow Control-C to interrupt FPGA configuration
1496 CFG_FPGA_CHECK_ERROR
1498 Check for configuration errors during FPGA bitfile
1499 loading. For example, abort during Virtex II
1500 configuration if the INIT_B line goes low (which
1501 indicated a CRC error).
1505 Maximum time to wait for the INIT_B line to deassert
1506 after PROB_B has been deasserted during a Virtex II
1507 FPGA configuration sequence. The default time is 500
1512 Maximum time to wait for BUSY to deassert during
1513 Virtex II FPGA configuration. The default is 5 mS.
1515 CFG_FPGA_WAIT_CONFIG
1517 Time to wait after FPGA configuration. The default is
1520 - Configuration Management:
1523 If defined, this string will be added to the U-Boot
1524 version information (U_BOOT_VERSION)
1526 - Vendor Parameter Protection:
1528 U-Boot considers the values of the environment
1529 variables "serial#" (Board Serial Number) and
1530 "ethaddr" (Ethernet Address) to be parameters that
1531 are set once by the board vendor / manufacturer, and
1532 protects these variables from casual modification by
1533 the user. Once set, these variables are read-only,
1534 and write or delete attempts are rejected. You can
1535 change this behviour:
1537 If CONFIG_ENV_OVERWRITE is #defined in your config
1538 file, the write protection for vendor parameters is
1539 completely disabled. Anybody can change or delete
1542 Alternatively, if you #define _both_ CONFIG_ETHADDR
1543 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1544 ethernet address is installed in the environment,
1545 which can be changed exactly ONCE by the user. [The
1546 serial# is unaffected by this, i. e. it remains
1552 Define this variable to enable the reservation of
1553 "protected RAM", i. e. RAM which is not overwritten
1554 by U-Boot. Define CONFIG_PRAM to hold the number of
1555 kB you want to reserve for pRAM. You can overwrite
1556 this default value by defining an environment
1557 variable "pram" to the number of kB you want to
1558 reserve. Note that the board info structure will
1559 still show the full amount of RAM. If pRAM is
1560 reserved, a new environment variable "mem" will
1561 automatically be defined to hold the amount of
1562 remaining RAM in a form that can be passed as boot
1563 argument to Linux, for instance like that:
1565 setenv bootargs ... mem=\${mem}
1568 This way you can tell Linux not to use this memory,
1569 either, which results in a memory region that will
1570 not be affected by reboots.
1572 *WARNING* If your board configuration uses automatic
1573 detection of the RAM size, you must make sure that
1574 this memory test is non-destructive. So far, the
1575 following board configurations are known to be
1578 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1579 HERMES, IP860, RPXlite, LWMON, LANTEC,
1580 PCU_E, FLAGADM, TQM8260
1585 Define this variable to stop the system in case of a
1586 fatal error, so that you have to reset it manually.
1587 This is probably NOT a good idea for an embedded
1588 system where you want to system to reboot
1589 automatically as fast as possible, but it may be
1590 useful during development since you can try to debug
1591 the conditions that lead to the situation.
1593 CONFIG_NET_RETRY_COUNT
1595 This variable defines the number of retries for
1596 network operations like ARP, RARP, TFTP, or BOOTP
1597 before giving up the operation. If not defined, a
1598 default value of 5 is used.
1600 - Command Interpreter:
1601 CONFIG_AUTO_COMPLETE
1603 Enable auto completion of commands using TAB.
1605 Note that this feature has NOT been implemented yet
1606 for the "hush" shell.
1611 Define this variable to enable the "hush" shell (from
1612 Busybox) as command line interpreter, thus enabling
1613 powerful command line syntax like
1614 if...then...else...fi conditionals or `&&' and '||'
1615 constructs ("shell scripts").
1617 If undefined, you get the old, much simpler behaviour
1618 with a somewhat smaller memory footprint.
1623 This defines the secondary prompt string, which is
1624 printed when the command interpreter needs more input
1625 to complete a command. Usually "> ".
1629 In the current implementation, the local variables
1630 space and global environment variables space are
1631 separated. Local variables are those you define by
1632 simply typing `name=value'. To access a local
1633 variable later on, you have write `$name' or
1634 `${name}'; to execute the contents of a variable
1635 directly type `$name' at the command prompt.
1637 Global environment variables are those you use
1638 setenv/printenv to work with. To run a command stored
1639 in such a variable, you need to use the run command,
1640 and you must not use the '$' sign to access them.
1642 To store commands and special characters in a
1643 variable, please use double quotation marks
1644 surrounding the whole text of the variable, instead
1645 of the backslashes before semicolons and special
1648 - Commandline Editing and History:
1649 CONFIG_CMDLINE_EDITING
1651 Enable editiong and History functions for interactive
1652 commandline input operations
1654 - Default Environment:
1655 CONFIG_EXTRA_ENV_SETTINGS
1657 Define this to contain any number of null terminated
1658 strings (variable = value pairs) that will be part of
1659 the default environment compiled into the boot image.
1661 For example, place something like this in your
1662 board's config file:
1664 #define CONFIG_EXTRA_ENV_SETTINGS \
1668 Warning: This method is based on knowledge about the
1669 internal format how the environment is stored by the
1670 U-Boot code. This is NOT an official, exported
1671 interface! Although it is unlikely that this format
1672 will change soon, there is no guarantee either.
1673 You better know what you are doing here.
1675 Note: overly (ab)use of the default environment is
1676 discouraged. Make sure to check other ways to preset
1677 the environment like the autoscript function or the
1680 - DataFlash Support:
1681 CONFIG_HAS_DATAFLASH
1683 Defining this option enables DataFlash features and
1684 allows to read/write in Dataflash via the standard
1687 - SystemACE Support:
1690 Adding this option adds support for Xilinx SystemACE
1691 chips attached via some sort of local bus. The address
1692 of the chip must alsh be defined in the
1693 CFG_SYSTEMACE_BASE macro. For example:
1695 #define CONFIG_SYSTEMACE
1696 #define CFG_SYSTEMACE_BASE 0xf0000000
1698 When SystemACE support is added, the "ace" device type
1699 becomes available to the fat commands, i.e. fatls.
1701 - TFTP Fixed UDP Port:
1704 If this is defined, the environment variable tftpsrcp
1705 is used to supply the TFTP UDP source port value.
1706 If tftpsrcp isn't defined, the normal pseudo-random port
1707 number generator is used.
1709 Also, the environment variable tftpdstp is used to supply
1710 the TFTP UDP destination port value. If tftpdstp isn't
1711 defined, the normal port 69 is used.
1713 The purpose for tftpsrcp is to allow a TFTP server to
1714 blindly start the TFTP transfer using the pre-configured
1715 target IP address and UDP port. This has the effect of
1716 "punching through" the (Windows XP) firewall, allowing
1717 the remainder of the TFTP transfer to proceed normally.
1718 A better solution is to properly configure the firewall,
1719 but sometimes that is not allowed.
1721 - Show boot progress:
1722 CONFIG_SHOW_BOOT_PROGRESS
1724 Defining this option allows to add some board-
1725 specific code (calling a user-provided function
1726 "show_boot_progress(int)") that enables you to show
1727 the system's boot progress on some display (for
1728 example, some LED's) on your board. At the moment,
1729 the following checkpoints are implemented:
1732 1 common/cmd_bootm.c before attempting to boot an image
1733 -1 common/cmd_bootm.c Image header has bad magic number
1734 2 common/cmd_bootm.c Image header has correct magic number
1735 -2 common/cmd_bootm.c Image header has bad checksum
1736 3 common/cmd_bootm.c Image header has correct checksum
1737 -3 common/cmd_bootm.c Image data has bad checksum
1738 4 common/cmd_bootm.c Image data has correct checksum
1739 -4 common/cmd_bootm.c Image is for unsupported architecture
1740 5 common/cmd_bootm.c Architecture check OK
1741 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1742 6 common/cmd_bootm.c Image Type check OK
1743 -6 common/cmd_bootm.c gunzip uncompression error
1744 -7 common/cmd_bootm.c Unimplemented compression type
1745 7 common/cmd_bootm.c Uncompression OK
1746 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1747 8 common/cmd_bootm.c Image Type check OK
1748 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1749 9 common/cmd_bootm.c Start initial ramdisk verification
1750 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1751 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1752 10 common/cmd_bootm.c Ramdisk header is OK
1753 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1754 11 common/cmd_bootm.c Ramdisk data has correct checksum
1755 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1756 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1757 13 common/cmd_bootm.c Start multifile image verification
1758 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1759 15 common/cmd_bootm.c All preparation done, transferring control to OS
1761 -30 lib_ppc/board.c Fatal error, hang the system
1762 -31 post/post.c POST test failed, detected by post_output_backlog()
1763 -32 post/post.c POST test failed, detected by post_run_single()
1765 -1 common/cmd_doc.c Bad usage of "doc" command
1766 -1 common/cmd_doc.c No boot device
1767 -1 common/cmd_doc.c Unknown Chip ID on boot device
1768 -1 common/cmd_doc.c Read Error on boot device
1769 -1 common/cmd_doc.c Image header has bad magic number
1771 -1 common/cmd_ide.c Bad usage of "ide" command
1772 -1 common/cmd_ide.c No boot device
1773 -1 common/cmd_ide.c Unknown boot device
1774 -1 common/cmd_ide.c Unknown partition table
1775 -1 common/cmd_ide.c Invalid partition type
1776 -1 common/cmd_ide.c Read Error on boot device
1777 -1 common/cmd_ide.c Image header has bad magic number
1779 -1 common/cmd_nand.c Bad usage of "nand" command
1780 -1 common/cmd_nand.c No boot device
1781 -1 common/cmd_nand.c Unknown Chip ID on boot device
1782 -1 common/cmd_nand.c Read Error on boot device
1783 -1 common/cmd_nand.c Image header has bad magic number
1785 -1 common/env_common.c Environment has a bad CRC, using default
1791 [so far only for SMDK2400 and TRAB boards]
1793 - Modem support endable:
1794 CONFIG_MODEM_SUPPORT
1796 - RTS/CTS Flow control enable:
1799 - Modem debug support:
1800 CONFIG_MODEM_SUPPORT_DEBUG
1802 Enables debugging stuff (char screen[1024], dbg())
1803 for modem support. Useful only with BDI2000.
1805 - Interrupt support (PPC):
1807 There are common interrupt_init() and timer_interrupt()
1808 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1809 for cpu specific initialization. interrupt_init_cpu()
1810 should set decrementer_count to appropriate value. If
1811 cpu resets decrementer automatically after interrupt
1812 (ppc4xx) it should set decrementer_count to zero.
1813 timer_interrupt() calls timer_interrupt_cpu() for cpu
1814 specific handling. If board has watchdog / status_led
1815 / other_activity_monitor it works automatically from
1816 general timer_interrupt().
1820 In the target system modem support is enabled when a
1821 specific key (key combination) is pressed during
1822 power-on. Otherwise U-Boot will boot normally
1823 (autoboot). The key_pressed() fuction is called from
1824 board_init(). Currently key_pressed() is a dummy
1825 function, returning 1 and thus enabling modem
1828 If there are no modem init strings in the
1829 environment, U-Boot proceed to autoboot; the
1830 previous output (banner, info printfs) will be
1833 See also: doc/README.Modem
1836 Configuration Settings:
1837 -----------------------
1839 - CFG_LONGHELP: Defined when you want long help messages included;
1840 undefine this when you're short of memory.
1842 - CFG_PROMPT: This is what U-Boot prints on the console to
1843 prompt for user input.
1845 - CFG_CBSIZE: Buffer size for input from the Console
1847 - CFG_PBSIZE: Buffer size for Console output
1849 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1851 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1852 the application (usually a Linux kernel) when it is
1855 - CFG_BAUDRATE_TABLE:
1856 List of legal baudrate settings for this board.
1858 - CFG_CONSOLE_INFO_QUIET
1859 Suppress display of console information at boot.
1861 - CFG_CONSOLE_IS_IN_ENV
1862 If the board specific function
1863 extern int overwrite_console (void);
1864 returns 1, the stdin, stderr and stdout are switched to the
1865 serial port, else the settings in the environment are used.
1867 - CFG_CONSOLE_OVERWRITE_ROUTINE
1868 Enable the call to overwrite_console().
1870 - CFG_CONSOLE_ENV_OVERWRITE
1871 Enable overwrite of previous console environment settings.
1873 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1874 Begin and End addresses of the area used by the
1878 Enable an alternate, more extensive memory test.
1880 - CFG_MEMTEST_SCRATCH:
1881 Scratch address used by the alternate memory test
1882 You only need to set this if address zero isn't writeable
1884 - CFG_TFTP_LOADADDR:
1885 Default load address for network file downloads
1887 - CFG_LOADS_BAUD_CHANGE:
1888 Enable temporary baudrate change while serial download
1891 Physical start address of SDRAM. _Must_ be 0 here.
1894 Physical start address of Motherboard I/O (if using a
1898 Physical start address of Flash memory.
1901 Physical start address of boot monitor code (set by
1902 make config files to be same as the text base address
1903 (TEXT_BASE) used when linking) - same as
1904 CFG_FLASH_BASE when booting from flash.
1907 Size of memory reserved for monitor code, used to
1908 determine _at_compile_time_ (!) if the environment is
1909 embedded within the U-Boot image, or in a separate
1913 Size of DRAM reserved for malloc() use.
1916 Normally compressed uImages are limited to an
1917 uncompressed size of 8 MBytes. If this is not enough,
1918 you can define CFG_BOOTM_LEN in your board config file
1919 to adjust this setting to your needs.
1922 Maximum size of memory mapped by the startup code of
1923 the Linux kernel; all data that must be processed by
1924 the Linux kernel (bd_info, boot arguments, eventually
1925 initrd image) must be put below this limit.
1927 - CFG_MAX_FLASH_BANKS:
1928 Max number of Flash memory banks
1930 - CFG_MAX_FLASH_SECT:
1931 Max number of sectors on a Flash chip
1933 - CFG_FLASH_ERASE_TOUT:
1934 Timeout for Flash erase operations (in ms)
1936 - CFG_FLASH_WRITE_TOUT:
1937 Timeout for Flash write operations (in ms)
1939 - CFG_FLASH_LOCK_TOUT
1940 Timeout for Flash set sector lock bit operation (in ms)
1942 - CFG_FLASH_UNLOCK_TOUT
1943 Timeout for Flash clear lock bits operation (in ms)
1945 - CFG_FLASH_PROTECTION
1946 If defined, hardware flash sectors protection is used
1947 instead of U-Boot software protection.
1949 - CFG_DIRECT_FLASH_TFTP:
1951 Enable TFTP transfers directly to flash memory;
1952 without this option such a download has to be
1953 performed in two steps: (1) download to RAM, and (2)
1954 copy from RAM to flash.
1956 The two-step approach is usually more reliable, since
1957 you can check if the download worked before you erase
1958 the flash, but in some situations (when sytem RAM is
1959 too limited to allow for a tempory copy of the
1960 downloaded image) this option may be very useful.
1963 Define if the flash driver uses extra elements in the
1964 common flash structure for storing flash geometry.
1966 - CFG_FLASH_CFI_DRIVER
1967 This option also enables the building of the cfi_flash driver
1968 in the drivers directory
1970 - CFG_FLASH_QUIET_TEST
1971 If this option is defined, the common CFI flash doesn't
1972 print it's warning upon not recognized FLASH banks. This
1973 is useful, if some of the configured banks are only
1974 optionally available.
1976 - CFG_RX_ETH_BUFFER:
1977 Defines the number of ethernet receive buffers. On some
1978 ethernet controllers it is recommended to set this value
1979 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1980 buffers can be full shortly after enabling the interface
1981 on high ethernet traffic.
1982 Defaults to 4 if not defined.
1984 The following definitions that deal with the placement and management
1985 of environment data (variable area); in general, we support the
1986 following configurations:
1988 - CFG_ENV_IS_IN_FLASH:
1990 Define this if the environment is in flash memory.
1992 a) The environment occupies one whole flash sector, which is
1993 "embedded" in the text segment with the U-Boot code. This
1994 happens usually with "bottom boot sector" or "top boot
1995 sector" type flash chips, which have several smaller
1996 sectors at the start or the end. For instance, such a
1997 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1998 such a case you would place the environment in one of the
1999 4 kB sectors - with U-Boot code before and after it. With
2000 "top boot sector" type flash chips, you would put the
2001 environment in one of the last sectors, leaving a gap
2002 between U-Boot and the environment.
2006 Offset of environment data (variable area) to the
2007 beginning of flash memory; for instance, with bottom boot
2008 type flash chips the second sector can be used: the offset
2009 for this sector is given here.
2011 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2015 This is just another way to specify the start address of
2016 the flash sector containing the environment (instead of
2019 - CFG_ENV_SECT_SIZE:
2021 Size of the sector containing the environment.
2024 b) Sometimes flash chips have few, equal sized, BIG sectors.
2025 In such a case you don't want to spend a whole sector for
2030 If you use this in combination with CFG_ENV_IS_IN_FLASH
2031 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2032 of this flash sector for the environment. This saves
2033 memory for the RAM copy of the environment.
2035 It may also save flash memory if you decide to use this
2036 when your environment is "embedded" within U-Boot code,
2037 since then the remainder of the flash sector could be used
2038 for U-Boot code. It should be pointed out that this is
2039 STRONGLY DISCOURAGED from a robustness point of view:
2040 updating the environment in flash makes it always
2041 necessary to erase the WHOLE sector. If something goes
2042 wrong before the contents has been restored from a copy in
2043 RAM, your target system will be dead.
2045 - CFG_ENV_ADDR_REDUND
2048 These settings describe a second storage area used to hold
2049 a redundand copy of the environment data, so that there is
2050 a valid backup copy in case there is a power failure during
2051 a "saveenv" operation.
2053 BE CAREFUL! Any changes to the flash layout, and some changes to the
2054 source code will make it necessary to adapt <board>/u-boot.lds*
2058 - CFG_ENV_IS_IN_NVRAM:
2060 Define this if you have some non-volatile memory device
2061 (NVRAM, battery buffered SRAM) which you want to use for the
2067 These two #defines are used to determin the memory area you
2068 want to use for environment. It is assumed that this memory
2069 can just be read and written to, without any special
2072 BE CAREFUL! The first access to the environment happens quite early
2073 in U-Boot initalization (when we try to get the setting of for the
2074 console baudrate). You *MUST* have mappend your NVRAM area then, or
2077 Please note that even with NVRAM we still use a copy of the
2078 environment in RAM: we could work on NVRAM directly, but we want to
2079 keep settings there always unmodified except somebody uses "saveenv"
2080 to save the current settings.
2083 - CFG_ENV_IS_IN_EEPROM:
2085 Use this if you have an EEPROM or similar serial access
2086 device and a driver for it.
2091 These two #defines specify the offset and size of the
2092 environment area within the total memory of your EEPROM.
2094 - CFG_I2C_EEPROM_ADDR:
2095 If defined, specified the chip address of the EEPROM device.
2096 The default address is zero.
2098 - CFG_EEPROM_PAGE_WRITE_BITS:
2099 If defined, the number of bits used to address bytes in a
2100 single page in the EEPROM device. A 64 byte page, for example
2101 would require six bits.
2103 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2104 If defined, the number of milliseconds to delay between
2105 page writes. The default is zero milliseconds.
2107 - CFG_I2C_EEPROM_ADDR_LEN:
2108 The length in bytes of the EEPROM memory array address. Note
2109 that this is NOT the chip address length!
2111 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2112 EEPROM chips that implement "address overflow" are ones
2113 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2114 address and the extra bits end up in the "chip address" bit
2115 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2118 Note that we consider the length of the address field to
2119 still be one byte because the extra address bits are hidden
2120 in the chip address.
2123 The size in bytes of the EEPROM device.
2126 - CFG_ENV_IS_IN_DATAFLASH:
2128 Define this if you have a DataFlash memory device which you
2129 want to use for the environment.
2135 These three #defines specify the offset and size of the
2136 environment area within the total memory of your DataFlash placed
2137 at the specified address.
2139 - CFG_ENV_IS_IN_NAND:
2141 Define this if you have a NAND device which you want to use
2142 for the environment.
2147 These two #defines specify the offset and size of the environment
2148 area within the first NAND device.
2150 - CFG_ENV_OFFSET_REDUND
2152 This setting describes a second storage area of CFG_ENV_SIZE
2153 size used to hold a redundant copy of the environment data,
2154 so that there is a valid backup copy in case there is a
2155 power failure during a "saveenv" operation.
2157 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2158 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2159 the NAND devices block size.
2161 - CFG_SPI_INIT_OFFSET
2163 Defines offset to the initial SPI buffer area in DPRAM. The
2164 area is used at an early stage (ROM part) if the environment
2165 is configured to reside in the SPI EEPROM: We need a 520 byte
2166 scratch DPRAM area. It is used between the two initialization
2167 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2168 to be a good choice since it makes it far enough from the
2169 start of the data area as well as from the stack pointer.
2171 Please note that the environment is read-only as long as the monitor
2172 has been relocated to RAM and a RAM copy of the environment has been
2173 created; also, when using EEPROM you will have to use getenv_r()
2174 until then to read environment variables.
2176 The environment is protected by a CRC32 checksum. Before the monitor
2177 is relocated into RAM, as a result of a bad CRC you will be working
2178 with the compiled-in default environment - *silently*!!! [This is
2179 necessary, because the first environment variable we need is the
2180 "baudrate" setting for the console - if we have a bad CRC, we don't
2181 have any device yet where we could complain.]
2183 Note: once the monitor has been relocated, then it will complain if
2184 the default environment is used; a new CRC is computed as soon as you
2185 use the "saveenv" command to store a valid environment.
2187 - CFG_FAULT_ECHO_LINK_DOWN:
2188 Echo the inverted Ethernet link state to the fault LED.
2190 Note: If this option is active, then CFG_FAULT_MII_ADDR
2191 also needs to be defined.
2193 - CFG_FAULT_MII_ADDR:
2194 MII address of the PHY to check for the Ethernet link state.
2196 - CFG_64BIT_VSPRINTF:
2197 Makes vsprintf (and all *printf functions) support printing
2198 of 64bit values by using the L quantifier
2200 - CFG_64BIT_STRTOUL:
2201 Adds simple_strtoull that returns a 64bit value
2203 Low Level (hardware related) configuration options:
2204 ---------------------------------------------------
2206 - CFG_CACHELINE_SIZE:
2207 Cache Line Size of the CPU.
2210 Default address of the IMMR after system reset.
2212 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2213 and RPXsuper) to be able to adjust the position of
2214 the IMMR register after a reset.
2216 - Floppy Disk Support:
2217 CFG_FDC_DRIVE_NUMBER
2219 the default drive number (default value 0)
2223 defines the spacing between fdc chipset registers
2228 defines the offset of register from address. It
2229 depends on which part of the data bus is connected to
2230 the fdc chipset. (default value 0)
2232 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2233 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2236 if CFG_FDC_HW_INIT is defined, then the function
2237 fdc_hw_init() is called at the beginning of the FDC
2238 setup. fdc_hw_init() must be provided by the board
2239 source code. It is used to make hardware dependant
2242 - CFG_IMMR: Physical address of the Internal Memory.
2243 DO NOT CHANGE unless you know exactly what you're
2244 doing! (11-4) [MPC8xx/82xx systems only]
2246 - CFG_INIT_RAM_ADDR:
2248 Start address of memory area that can be used for
2249 initial data and stack; please note that this must be
2250 writable memory that is working WITHOUT special
2251 initialization, i. e. you CANNOT use normal RAM which
2252 will become available only after programming the
2253 memory controller and running certain initialization
2256 U-Boot uses the following memory types:
2257 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2258 - MPC824X: data cache
2259 - PPC4xx: data cache
2261 - CFG_GBL_DATA_OFFSET:
2263 Offset of the initial data structure in the memory
2264 area defined by CFG_INIT_RAM_ADDR. Usually
2265 CFG_GBL_DATA_OFFSET is chosen such that the initial
2266 data is located at the end of the available space
2267 (sometimes written as (CFG_INIT_RAM_END -
2268 CFG_INIT_DATA_SIZE), and the initial stack is just
2269 below that area (growing from (CFG_INIT_RAM_ADDR +
2270 CFG_GBL_DATA_OFFSET) downward.
2273 On the MPC824X (or other systems that use the data
2274 cache for initial memory) the address chosen for
2275 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2276 point to an otherwise UNUSED address space between
2277 the top of RAM and the start of the PCI space.
2279 - CFG_SIUMCR: SIU Module Configuration (11-6)
2281 - CFG_SYPCR: System Protection Control (11-9)
2283 - CFG_TBSCR: Time Base Status and Control (11-26)
2285 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2287 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2289 - CFG_SCCR: System Clock and reset Control Register (15-27)
2291 - CFG_OR_TIMING_SDRAM:
2295 periodic timer for refresh
2297 - CFG_DER: Debug Event Register (37-47)
2299 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2300 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2301 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2303 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2305 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2306 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2307 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2308 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2310 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2311 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2312 Machine Mode Register and Memory Periodic Timer
2313 Prescaler definitions (SDRAM timing)
2315 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2316 enable I2C microcode relocation patch (MPC8xx);
2317 define relocation offset in DPRAM [DSP2]
2319 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2320 enable SPI microcode relocation patch (MPC8xx);
2321 define relocation offset in DPRAM [SCC4]
2324 Use OSCM clock mode on MBX8xx board. Be careful,
2325 wrong setting might damage your board. Read
2326 doc/README.MBX before setting this variable!
2328 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2329 Offset of the bootmode word in DPRAM used by post
2330 (Power On Self Tests). This definition overrides
2331 #define'd default value in commproc.h resp.
2334 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2335 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2336 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2337 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2338 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2339 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2340 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2341 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2342 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2345 Get DDR timing information from an I2C EEPROM. Common with pluggable
2346 memory modules such as SODIMMs
2348 I2C address of the SPD EEPROM
2351 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2352 Note that the value must resolve to something your driver can deal with.
2354 - CFG_83XX_DDR_USES_CS0
2355 Only for 83xx systems. If specified, then DDR should be configured
2356 using CS0 and CS1 instead of CS2 and CS3.
2358 - CFG_83XX_DDR_USES_CS0
2359 Only for 83xx systems. If specified, then DDR should be configured
2360 using CS0 and CS1 instead of CS2 and CS3.
2362 - CONFIG_ETHER_ON_FEC[12]
2363 Define to enable FEC[12] on a 8xx series processor.
2365 - CONFIG_FEC[12]_PHY
2366 Define to the hardcoded PHY address which corresponds
2367 to the given FEC; i. e.
2368 #define CONFIG_FEC1_PHY 4
2369 means that the PHY with address 4 is connected to FEC1
2371 When set to -1, means to probe for first available.
2373 - CONFIG_FEC[12]_PHY_NORXERR
2374 The PHY does not have a RXERR line (RMII only).
2375 (so program the FEC to ignore it).
2378 Enable RMII mode for all FECs.
2379 Note that this is a global option, we can't
2380 have one FEC in standard MII mode and another in RMII mode.
2382 - CONFIG_CRC32_VERIFY
2383 Add a verify option to the crc32 command.
2386 => crc32 -v <address> <count> <crc32>
2388 Where address/count indicate a memory area
2389 and crc32 is the correct crc32 which the
2393 Add the "loopw" memory command. This only takes effect if
2394 the memory commands are activated globally (CFG_CMD_MEM).
2397 Add the "mdc" and "mwc" memory commands. These are cyclic
2402 This command will print 4 bytes (10,11,12,13) each 500 ms.
2404 => mwc.l 100 12345678 10
2405 This command will write 12345678 to address 100 all 10 ms.
2407 This only takes effect if the memory commands are activated
2408 globally (CFG_CMD_MEM).
2410 - CONFIG_SKIP_LOWLEVEL_INIT
2411 - CONFIG_SKIP_RELOCATE_UBOOT
2413 [ARM only] If these variables are defined, then
2414 certain low level initializations (like setting up
2415 the memory controller) are omitted and/or U-Boot does
2416 not relocate itself into RAM.
2417 Normally these variables MUST NOT be defined. The
2418 only exception is when U-Boot is loaded (to RAM) by
2419 some other boot loader or by a debugger which
2420 performs these intializations itself.
2423 Building the Software:
2424 ======================
2426 Building U-Boot has been tested in native PPC environments (on a
2427 PowerBook G3 running LinuxPPC 2000) and in cross environments
2428 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2431 If you are not using a native PPC environment, it is assumed that you
2432 have the GNU cross compiling tools available in your path and named
2433 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2434 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2435 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2438 CROSS_COMPILE = ppc_4xx-
2441 U-Boot is intended to be simple to build. After installing the
2442 sources you must configure U-Boot for one specific board type. This
2447 where "NAME_config" is the name of one of the existing
2448 configurations; the following names are supported:
2450 ADCIOP_config FPS860L_config omap730p2_config
2451 ADS860_config GEN860T_config pcu_e_config
2453 AR405_config GENIETV_config PIP405_config
2454 at91rm9200dk_config GTH_config QS823_config
2455 CANBT_config hermes_config QS850_config
2456 cmi_mpc5xx_config hymod_config QS860T_config
2457 cogent_common_config IP860_config RPXlite_config
2458 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2459 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2460 CPCI405_config JSE_config rsdproto_config
2461 CPCIISER4_config LANTEC_config Sandpoint8240_config
2462 csb272_config lwmon_config sbc8260_config
2463 CU824_config MBX860T_config sbc8560_33_config
2464 DUET_ADS_config MBX_config sbc8560_66_config
2465 EBONY_config mpc7448hpc2_config SM850_config
2466 ELPT860_config MPC8260ADS_config SPD823TS_config
2467 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2468 ETX094_config MPC8540EVAL_config SXNI855T_config
2469 FADS823_config NMPC8560ADS_config TQM823L_config
2470 FADS850SAR_config NETVIA_config TQM850L_config
2471 FADS860T_config omap1510inn_config TQM855L_config
2472 FPS850L_config omap1610h2_config TQM860L_config
2473 omap1610inn_config walnut_config
2474 omap5912osk_config Yukon8220_config
2475 omap2420h4_config ZPC1900_config
2477 Note: for some board special configuration names may exist; check if
2478 additional information is available from the board vendor; for
2479 instance, the TQM823L systems are available without (standard)
2480 or with LCD support. You can select such additional "features"
2481 when chosing the configuration, i. e.
2484 - will configure for a plain TQM823L, i. e. no LCD support
2486 make TQM823L_LCD_config
2487 - will configure for a TQM823L with U-Boot console on LCD
2492 Finally, type "make all", and you should get some working U-Boot
2493 images ready for download to / installation on your system:
2495 - "u-boot.bin" is a raw binary image
2496 - "u-boot" is an image in ELF binary format
2497 - "u-boot.srec" is in Motorola S-Record format
2499 By default the build is performed locally and the objects are saved
2500 in the source directory. One of the two methods can be used to change
2501 this behavior and build U-Boot to some external directory:
2503 1. Add O= to the make command line invocations:
2505 make O=/tmp/build distclean
2506 make O=/tmp/build NAME_config
2507 make O=/tmp/build all
2509 2. Set environment variable BUILD_DIR to point to the desired location:
2511 export BUILD_DIR=/tmp/build
2516 Note that the command line "O=" setting overrides the BUILD_DIR environment
2520 Please be aware that the Makefiles assume you are using GNU make, so
2521 for instance on NetBSD you might need to use "gmake" instead of
2525 If the system board that you have is not listed, then you will need
2526 to port U-Boot to your hardware platform. To do this, follow these
2529 1. Add a new configuration option for your board to the toplevel
2530 "Makefile" and to the "MAKEALL" script, using the existing
2531 entries as examples. Note that here and at many other places
2532 boards and other names are listed in alphabetical sort order. Please
2534 2. Create a new directory to hold your board specific code. Add any
2535 files you need. In your board directory, you will need at least
2536 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2537 3. Create a new configuration file "include/configs/<board>.h" for
2539 3. If you're porting U-Boot to a new CPU, then also create a new
2540 directory to hold your CPU specific code. Add any files you need.
2541 4. Run "make <board>_config" with your new name.
2542 5. Type "make", and you should get a working "u-boot.srec" file
2543 to be installed on your target system.
2544 6. Debug and solve any problems that might arise.
2545 [Of course, this last step is much harder than it sounds.]
2548 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2549 ==============================================================
2551 If you have modified U-Boot sources (for instance added a new board
2552 or support for new devices, a new CPU, etc.) you are expected to
2553 provide feedback to the other developers. The feedback normally takes
2554 the form of a "patch", i. e. a context diff against a certain (latest
2555 official or latest in CVS) version of U-Boot sources.
2557 But before you submit such a patch, please verify that your modifi-
2558 cation did not break existing code. At least make sure that *ALL* of
2559 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2560 just run the "MAKEALL" script, which will configure and build U-Boot
2561 for ALL supported system. Be warned, this will take a while. You can
2562 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2563 environment variable to the script, i. e. to use the cross tools from
2564 MontaVista's Hard Hat Linux you can type
2566 CROSS_COMPILE=ppc_8xx- MAKEALL
2568 or to build on a native PowerPC system you can type
2570 CROSS_COMPILE=' ' MAKEALL
2572 When using the MAKEALL script, the default behaviour is to build U-Boot
2573 in the source directory. This location can be changed by setting the
2574 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2575 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2576 <source dir>/LOG directory. This default location can be changed by
2577 setting the MAKEALL_LOGDIR environment variable. For example:
2579 export BUILD_DIR=/tmp/build
2580 export MAKEALL_LOGDIR=/tmp/log
2581 CROSS_COMPILE=ppc_8xx- MAKEALL
2583 With the above settings build objects are saved in the /tmp/build, log
2584 files are saved in the /tmp/log and the source tree remains clean during
2585 the whole build process.
2588 See also "U-Boot Porting Guide" below.
2591 Monitor Commands - Overview:
2592 ============================
2594 go - start application at address 'addr'
2595 run - run commands in an environment variable
2596 bootm - boot application image from memory
2597 bootp - boot image via network using BootP/TFTP protocol
2598 tftpboot- boot image via network using TFTP protocol
2599 and env variables "ipaddr" and "serverip"
2600 (and eventually "gatewayip")
2601 rarpboot- boot image via network using RARP/TFTP protocol
2602 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2603 loads - load S-Record file over serial line
2604 loadb - load binary file over serial line (kermit mode)
2606 mm - memory modify (auto-incrementing)
2607 nm - memory modify (constant address)
2608 mw - memory write (fill)
2610 cmp - memory compare
2611 crc32 - checksum calculation
2612 imd - i2c memory display
2613 imm - i2c memory modify (auto-incrementing)
2614 inm - i2c memory modify (constant address)
2615 imw - i2c memory write (fill)
2616 icrc32 - i2c checksum calculation
2617 iprobe - probe to discover valid I2C chip addresses
2618 iloop - infinite loop on address range
2619 isdram - print SDRAM configuration information
2620 sspi - SPI utility commands
2621 base - print or set address offset
2622 printenv- print environment variables
2623 setenv - set environment variables
2624 saveenv - save environment variables to persistent storage
2625 protect - enable or disable FLASH write protection
2626 erase - erase FLASH memory
2627 flinfo - print FLASH memory information
2628 bdinfo - print Board Info structure
2629 iminfo - print header information for application image
2630 coninfo - print console devices and informations
2631 ide - IDE sub-system
2632 loop - infinite loop on address range
2633 loopw - infinite write loop on address range
2634 mtest - simple RAM test
2635 icache - enable or disable instruction cache
2636 dcache - enable or disable data cache
2637 reset - Perform RESET of the CPU
2638 echo - echo args to console
2639 version - print monitor version
2640 help - print online help
2641 ? - alias for 'help'
2644 Monitor Commands - Detailed Description:
2645 ========================================
2649 For now: just type "help <command>".
2652 Environment Variables:
2653 ======================
2655 U-Boot supports user configuration using Environment Variables which
2656 can be made persistent by saving to Flash memory.
2658 Environment Variables are set using "setenv", printed using
2659 "printenv", and saved to Flash using "saveenv". Using "setenv"
2660 without a value can be used to delete a variable from the
2661 environment. As long as you don't save the environment you are
2662 working with an in-memory copy. In case the Flash area containing the
2663 environment is erased by accident, a default environment is provided.
2665 Some configuration options can be set using Environment Variables:
2667 baudrate - see CONFIG_BAUDRATE
2669 bootdelay - see CONFIG_BOOTDELAY
2671 bootcmd - see CONFIG_BOOTCOMMAND
2673 bootargs - Boot arguments when booting an RTOS image
2675 bootfile - Name of the image to load with TFTP
2677 autoload - if set to "no" (any string beginning with 'n'),
2678 "bootp" will just load perform a lookup of the
2679 configuration from the BOOTP server, but not try to
2680 load any image using TFTP
2682 autostart - if set to "yes", an image loaded using the "bootp",
2683 "rarpboot", "tftpboot" or "diskboot" commands will
2684 be automatically started (by internally calling
2687 If set to "no", a standalone image passed to the
2688 "bootm" command will be copied to the load address
2689 (and eventually uncompressed), but NOT be started.
2690 This can be used to load and uncompress arbitrary
2693 i2cfast - (PPC405GP|PPC405EP only)
2694 if set to 'y' configures Linux I2C driver for fast
2695 mode (400kHZ). This environment variable is used in
2696 initialization code. So, for changes to be effective
2697 it must be saved and board must be reset.
2699 initrd_high - restrict positioning of initrd images:
2700 If this variable is not set, initrd images will be
2701 copied to the highest possible address in RAM; this
2702 is usually what you want since it allows for
2703 maximum initrd size. If for some reason you want to
2704 make sure that the initrd image is loaded below the
2705 CFG_BOOTMAPSZ limit, you can set this environment
2706 variable to a value of "no" or "off" or "0".
2707 Alternatively, you can set it to a maximum upper
2708 address to use (U-Boot will still check that it
2709 does not overwrite the U-Boot stack and data).
2711 For instance, when you have a system with 16 MB
2712 RAM, and want to reserve 4 MB from use by Linux,
2713 you can do this by adding "mem=12M" to the value of
2714 the "bootargs" variable. However, now you must make
2715 sure that the initrd image is placed in the first
2716 12 MB as well - this can be done with
2718 setenv initrd_high 00c00000
2720 If you set initrd_high to 0xFFFFFFFF, this is an
2721 indication to U-Boot that all addresses are legal
2722 for the Linux kernel, including addresses in flash
2723 memory. In this case U-Boot will NOT COPY the
2724 ramdisk at all. This may be useful to reduce the
2725 boot time on your system, but requires that this
2726 feature is supported by your Linux kernel.
2728 ipaddr - IP address; needed for tftpboot command
2730 loadaddr - Default load address for commands like "bootp",
2731 "rarpboot", "tftpboot", "loadb" or "diskboot"
2733 loads_echo - see CONFIG_LOADS_ECHO
2735 serverip - TFTP server IP address; needed for tftpboot command
2737 bootretry - see CONFIG_BOOT_RETRY_TIME
2739 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2741 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2743 ethprime - When CONFIG_NET_MULTI is enabled controls which
2744 interface is used first.
2746 ethact - When CONFIG_NET_MULTI is enabled controls which
2747 interface is currently active. For example you
2748 can do the following
2750 => setenv ethact FEC ETHERNET
2751 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2752 => setenv ethact SCC ETHERNET
2753 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2755 netretry - When set to "no" each network operation will
2756 either succeed or fail without retrying.
2757 When set to "once" the network operation will
2758 fail when all the available network interfaces
2759 are tried once without success.
2760 Useful on scripts which control the retry operation
2763 tftpsrcport - If this is set, the value is used for TFTP's
2766 tftpdstport - If this is set, the value is used for TFTP's UDP
2767 destination port instead of the Well Know Port 69.
2769 vlan - When set to a value < 4095 the traffic over
2770 ethernet is encapsulated/received over 802.1q
2773 The following environment variables may be used and automatically
2774 updated by the network boot commands ("bootp" and "rarpboot"),
2775 depending the information provided by your boot server:
2777 bootfile - see above
2778 dnsip - IP address of your Domain Name Server
2779 dnsip2 - IP address of your secondary Domain Name Server
2780 gatewayip - IP address of the Gateway (Router) to use
2781 hostname - Target hostname
2783 netmask - Subnet Mask
2784 rootpath - Pathname of the root filesystem on the NFS server
2785 serverip - see above
2788 There are two special Environment Variables:
2790 serial# - contains hardware identification information such
2791 as type string and/or serial number
2792 ethaddr - Ethernet address
2794 These variables can be set only once (usually during manufacturing of
2795 the board). U-Boot refuses to delete or overwrite these variables
2796 once they have been set once.
2799 Further special Environment Variables:
2801 ver - Contains the U-Boot version string as printed
2802 with the "version" command. This variable is
2803 readonly (see CONFIG_VERSION_VARIABLE).
2806 Please note that changes to some configuration parameters may take
2807 only effect after the next boot (yes, that's just like Windoze :-).
2810 Command Line Parsing:
2811 =====================
2813 There are two different command line parsers available with U-Boot:
2814 the old "simple" one, and the much more powerful "hush" shell:
2816 Old, simple command line parser:
2817 --------------------------------
2819 - supports environment variables (through setenv / saveenv commands)
2820 - several commands on one line, separated by ';'
2821 - variable substitution using "... ${name} ..." syntax
2822 - special characters ('$', ';') can be escaped by prefixing with '\',
2824 setenv bootcmd bootm \${address}
2825 - You can also escape text by enclosing in single apostrophes, for example:
2826 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2831 - similar to Bourne shell, with control structures like
2832 if...then...else...fi, for...do...done; while...do...done,
2833 until...do...done, ...
2834 - supports environment ("global") variables (through setenv / saveenv
2835 commands) and local shell variables (through standard shell syntax
2836 "name=value"); only environment variables can be used with "run"
2842 (1) If a command line (or an environment variable executed by a "run"
2843 command) contains several commands separated by semicolon, and
2844 one of these commands fails, then the remaining commands will be
2847 (2) If you execute several variables with one call to run (i. e.
2848 calling run with a list af variables as arguments), any failing
2849 command will cause "run" to terminate, i. e. the remaining
2850 variables are not executed.
2852 Note for Redundant Ethernet Interfaces:
2853 =======================================
2855 Some boards come with redundant ethernet interfaces; U-Boot supports
2856 such configurations and is capable of automatic selection of a
2857 "working" interface when needed. MAC assignment works as follows:
2859 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2860 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2861 "eth1addr" (=>eth1), "eth2addr", ...
2863 If the network interface stores some valid MAC address (for instance
2864 in SROM), this is used as default address if there is NO correspon-
2865 ding setting in the environment; if the corresponding environment
2866 variable is set, this overrides the settings in the card; that means:
2868 o If the SROM has a valid MAC address, and there is no address in the
2869 environment, the SROM's address is used.
2871 o If there is no valid address in the SROM, and a definition in the
2872 environment exists, then the value from the environment variable is
2875 o If both the SROM and the environment contain a MAC address, and
2876 both addresses are the same, this MAC address is used.
2878 o If both the SROM and the environment contain a MAC address, and the
2879 addresses differ, the value from the environment is used and a
2882 o If neither SROM nor the environment contain a MAC address, an error
2889 The "boot" commands of this monitor operate on "image" files which
2890 can be basicly anything, preceeded by a special header; see the
2891 definitions in include/image.h for details; basicly, the header
2892 defines the following image properties:
2894 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2895 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2896 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2897 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2898 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2899 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2900 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2901 * Compression Type (uncompressed, gzip, bzip2)
2907 The header is marked by a special Magic Number, and both the header
2908 and the data portions of the image are secured against corruption by
2915 Although U-Boot should support any OS or standalone application
2916 easily, the main focus has always been on Linux during the design of
2919 U-Boot includes many features that so far have been part of some
2920 special "boot loader" code within the Linux kernel. Also, any
2921 "initrd" images to be used are no longer part of one big Linux image;
2922 instead, kernel and "initrd" are separate images. This implementation
2923 serves several purposes:
2925 - the same features can be used for other OS or standalone
2926 applications (for instance: using compressed images to reduce the
2927 Flash memory footprint)
2929 - it becomes much easier to port new Linux kernel versions because
2930 lots of low-level, hardware dependent stuff are done by U-Boot
2932 - the same Linux kernel image can now be used with different "initrd"
2933 images; of course this also means that different kernel images can
2934 be run with the same "initrd". This makes testing easier (you don't
2935 have to build a new "zImage.initrd" Linux image when you just
2936 change a file in your "initrd"). Also, a field-upgrade of the
2937 software is easier now.
2943 Porting Linux to U-Boot based systems:
2944 ---------------------------------------
2946 U-Boot cannot save you from doing all the necessary modifications to
2947 configure the Linux device drivers for use with your target hardware
2948 (no, we don't intend to provide a full virtual machine interface to
2951 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2953 Just make sure your machine specific header file (for instance
2954 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2955 Information structure as we define in include/u-boot.h, and make
2956 sure that your definition of IMAP_ADDR uses the same value as your
2957 U-Boot configuration in CFG_IMMR.
2960 Configuring the Linux kernel:
2961 -----------------------------
2963 No specific requirements for U-Boot. Make sure you have some root
2964 device (initial ramdisk, NFS) for your target system.
2967 Building a Linux Image:
2968 -----------------------
2970 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2971 not used. If you use recent kernel source, a new build target
2972 "uImage" will exist which automatically builds an image usable by
2973 U-Boot. Most older kernels also have support for a "pImage" target,
2974 which was introduced for our predecessor project PPCBoot and uses a
2975 100% compatible format.
2984 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2985 encapsulate a compressed Linux kernel image with header information,
2986 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2988 * build a standard "vmlinux" kernel image (in ELF binary format):
2990 * convert the kernel into a raw binary image:
2992 ${CROSS_COMPILE}-objcopy -O binary \
2993 -R .note -R .comment \
2994 -S vmlinux linux.bin
2996 * compress the binary image:
3000 * package compressed binary image for U-Boot:
3002 mkimage -A ppc -O linux -T kernel -C gzip \
3003 -a 0 -e 0 -n "Linux Kernel Image" \
3004 -d linux.bin.gz uImage
3007 The "mkimage" tool can also be used to create ramdisk images for use
3008 with U-Boot, either separated from the Linux kernel image, or
3009 combined into one file. "mkimage" encapsulates the images with a 64
3010 byte header containing information about target architecture,
3011 operating system, image type, compression method, entry points, time
3012 stamp, CRC32 checksums, etc.
3014 "mkimage" can be called in two ways: to verify existing images and
3015 print the header information, or to build new images.
3017 In the first form (with "-l" option) mkimage lists the information
3018 contained in the header of an existing U-Boot image; this includes
3019 checksum verification:
3021 tools/mkimage -l image
3022 -l ==> list image header information
3024 The second form (with "-d" option) is used to build a U-Boot image
3025 from a "data file" which is used as image payload:
3027 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3028 -n name -d data_file image
3029 -A ==> set architecture to 'arch'
3030 -O ==> set operating system to 'os'
3031 -T ==> set image type to 'type'
3032 -C ==> set compression type 'comp'
3033 -a ==> set load address to 'addr' (hex)
3034 -e ==> set entry point to 'ep' (hex)
3035 -n ==> set image name to 'name'
3036 -d ==> use image data from 'datafile'
3038 Right now, all Linux kernels for PowerPC systems use the same load
3039 address (0x00000000), but the entry point address depends on the
3042 - 2.2.x kernels have the entry point at 0x0000000C,
3043 - 2.3.x and later kernels have the entry point at 0x00000000.
3045 So a typical call to build a U-Boot image would read:
3047 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3048 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3049 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3050 > examples/uImage.TQM850L
3051 Image Name: 2.4.4 kernel for TQM850L
3052 Created: Wed Jul 19 02:34:59 2000
3053 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3054 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3055 Load Address: 0x00000000
3056 Entry Point: 0x00000000
3058 To verify the contents of the image (or check for corruption):
3060 -> tools/mkimage -l examples/uImage.TQM850L
3061 Image Name: 2.4.4 kernel for TQM850L
3062 Created: Wed Jul 19 02:34:59 2000
3063 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3064 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3065 Load Address: 0x00000000
3066 Entry Point: 0x00000000
3068 NOTE: for embedded systems where boot time is critical you can trade
3069 speed for memory and install an UNCOMPRESSED image instead: this
3070 needs more space in Flash, but boots much faster since it does not
3071 need to be uncompressed:
3073 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3074 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3075 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3076 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3077 > examples/uImage.TQM850L-uncompressed
3078 Image Name: 2.4.4 kernel for TQM850L
3079 Created: Wed Jul 19 02:34:59 2000
3080 Image Type: PowerPC Linux Kernel Image (uncompressed)
3081 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3082 Load Address: 0x00000000
3083 Entry Point: 0x00000000
3086 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3087 when your kernel is intended to use an initial ramdisk:
3089 -> tools/mkimage -n 'Simple Ramdisk Image' \
3090 > -A ppc -O linux -T ramdisk -C gzip \
3091 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3092 Image Name: Simple Ramdisk Image
3093 Created: Wed Jan 12 14:01:50 2000
3094 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3095 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3096 Load Address: 0x00000000
3097 Entry Point: 0x00000000
3100 Installing a Linux Image:
3101 -------------------------
3103 To downloading a U-Boot image over the serial (console) interface,
3104 you must convert the image to S-Record format:
3106 objcopy -I binary -O srec examples/image examples/image.srec
3108 The 'objcopy' does not understand the information in the U-Boot
3109 image header, so the resulting S-Record file will be relative to
3110 address 0x00000000. To load it to a given address, you need to
3111 specify the target address as 'offset' parameter with the 'loads'
3114 Example: install the image to address 0x40100000 (which on the
3115 TQM8xxL is in the first Flash bank):
3117 => erase 40100000 401FFFFF
3123 ## Ready for S-Record download ...
3124 ~>examples/image.srec
3125 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3127 15989 15990 15991 15992
3128 [file transfer complete]
3130 ## Start Addr = 0x00000000
3133 You can check the success of the download using the 'iminfo' command;
3134 this includes a checksum verification so you can be sure no data
3135 corruption happened:
3139 ## Checking Image at 40100000 ...
3140 Image Name: 2.2.13 for initrd on TQM850L
3141 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3142 Data Size: 335725 Bytes = 327 kB = 0 MB
3143 Load Address: 00000000
3144 Entry Point: 0000000c
3145 Verifying Checksum ... OK
3151 The "bootm" command is used to boot an application that is stored in
3152 memory (RAM or Flash). In case of a Linux kernel image, the contents
3153 of the "bootargs" environment variable is passed to the kernel as
3154 parameters. You can check and modify this variable using the
3155 "printenv" and "setenv" commands:
3158 => printenv bootargs
3159 bootargs=root=/dev/ram
3161 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3163 => printenv bootargs
3164 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3167 ## Booting Linux kernel at 40020000 ...
3168 Image Name: 2.2.13 for NFS on TQM850L
3169 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3170 Data Size: 381681 Bytes = 372 kB = 0 MB
3171 Load Address: 00000000
3172 Entry Point: 0000000c
3173 Verifying Checksum ... OK
3174 Uncompressing Kernel Image ... OK
3175 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
3176 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3177 time_init: decrementer frequency = 187500000/60
3178 Calibrating delay loop... 49.77 BogoMIPS
3179 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3182 If you want to boot a Linux kernel with initial ram disk, you pass
3183 the memory addresses of both the kernel and the initrd image (PPBCOOT
3184 format!) to the "bootm" command:
3186 => imi 40100000 40200000
3188 ## Checking Image at 40100000 ...
3189 Image Name: 2.2.13 for initrd on TQM850L
3190 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3191 Data Size: 335725 Bytes = 327 kB = 0 MB
3192 Load Address: 00000000
3193 Entry Point: 0000000c
3194 Verifying Checksum ... OK
3196 ## Checking Image at 40200000 ...
3197 Image Name: Simple Ramdisk Image
3198 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3199 Data Size: 566530 Bytes = 553 kB = 0 MB
3200 Load Address: 00000000
3201 Entry Point: 00000000
3202 Verifying Checksum ... OK
3204 => bootm 40100000 40200000
3205 ## Booting Linux kernel at 40100000 ...
3206 Image Name: 2.2.13 for initrd on TQM850L
3207 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3208 Data Size: 335725 Bytes = 327 kB = 0 MB
3209 Load Address: 00000000
3210 Entry Point: 0000000c
3211 Verifying Checksum ... OK
3212 Uncompressing Kernel Image ... OK
3213 ## Loading RAMDisk Image at 40200000 ...
3214 Image Name: Simple Ramdisk Image
3215 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3216 Data Size: 566530 Bytes = 553 kB = 0 MB
3217 Load Address: 00000000
3218 Entry Point: 00000000
3219 Verifying Checksum ... OK
3220 Loading Ramdisk ... OK
3221 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
3222 Boot arguments: root=/dev/ram
3223 time_init: decrementer frequency = 187500000/60
3224 Calibrating delay loop... 49.77 BogoMIPS
3226 RAMDISK: Compressed image found at block 0
3227 VFS: Mounted root (ext2 filesystem).
3231 Boot Linux and pass a flat device tree:
3234 First, U-Boot must be compiled with the appropriate defines. See the section
3235 titled "Linux Kernel Interface" above for a more in depth explanation. The
3236 following is an example of how to start a kernel and pass an updated
3242 oft=oftrees/mpc8540ads.dtb
3243 => tftp $oftaddr $oft
3244 Speed: 1000, full duplex
3246 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3247 Filename 'oftrees/mpc8540ads.dtb'.
3248 Load address: 0x300000
3251 Bytes transferred = 4106 (100a hex)
3252 => tftp $loadaddr $bootfile
3253 Speed: 1000, full duplex
3255 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3257 Load address: 0x200000
3258 Loading:############
3260 Bytes transferred = 1029407 (fb51f hex)
3265 => bootm $loadaddr - $oftaddr
3266 ## Booting image at 00200000 ...
3267 Image Name: Linux-2.6.17-dirty
3268 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3269 Data Size: 1029343 Bytes = 1005.2 kB
3270 Load Address: 00000000
3271 Entry Point: 00000000
3272 Verifying Checksum ... OK
3273 Uncompressing Kernel Image ... OK
3274 Booting using flat device tree at 0x300000
3275 Using MPC85xx ADS machine description
3276 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3280 More About U-Boot Image Types:
3281 ------------------------------
3283 U-Boot supports the following image types:
3285 "Standalone Programs" are directly runnable in the environment
3286 provided by U-Boot; it is expected that (if they behave
3287 well) you can continue to work in U-Boot after return from
3288 the Standalone Program.
3289 "OS Kernel Images" are usually images of some Embedded OS which
3290 will take over control completely. Usually these programs
3291 will install their own set of exception handlers, device
3292 drivers, set up the MMU, etc. - this means, that you cannot
3293 expect to re-enter U-Boot except by resetting the CPU.
3294 "RAMDisk Images" are more or less just data blocks, and their
3295 parameters (address, size) are passed to an OS kernel that is
3297 "Multi-File Images" contain several images, typically an OS
3298 (Linux) kernel image and one or more data images like
3299 RAMDisks. This construct is useful for instance when you want
3300 to boot over the network using BOOTP etc., where the boot
3301 server provides just a single image file, but you want to get
3302 for instance an OS kernel and a RAMDisk image.
3304 "Multi-File Images" start with a list of image sizes, each
3305 image size (in bytes) specified by an "uint32_t" in network
3306 byte order. This list is terminated by an "(uint32_t)0".
3307 Immediately after the terminating 0 follow the images, one by
3308 one, all aligned on "uint32_t" boundaries (size rounded up to
3309 a multiple of 4 bytes).
3311 "Firmware Images" are binary images containing firmware (like
3312 U-Boot or FPGA images) which usually will be programmed to
3315 "Script files" are command sequences that will be executed by
3316 U-Boot's command interpreter; this feature is especially
3317 useful when you configure U-Boot to use a real shell (hush)
3318 as command interpreter.
3324 One of the features of U-Boot is that you can dynamically load and
3325 run "standalone" applications, which can use some resources of
3326 U-Boot like console I/O functions or interrupt services.
3328 Two simple examples are included with the sources:
3333 'examples/hello_world.c' contains a small "Hello World" Demo
3334 application; it is automatically compiled when you build U-Boot.
3335 It's configured to run at address 0x00040004, so you can play with it
3339 ## Ready for S-Record download ...
3340 ~>examples/hello_world.srec
3341 1 2 3 4 5 6 7 8 9 10 11 ...
3342 [file transfer complete]
3344 ## Start Addr = 0x00040004
3346 => go 40004 Hello World! This is a test.
3347 ## Starting application at 0x00040004 ...
3358 Hit any key to exit ...
3360 ## Application terminated, rc = 0x0
3362 Another example, which demonstrates how to register a CPM interrupt
3363 handler with the U-Boot code, can be found in 'examples/timer.c'.
3364 Here, a CPM timer is set up to generate an interrupt every second.
3365 The interrupt service routine is trivial, just printing a '.'
3366 character, but this is just a demo program. The application can be
3367 controlled by the following keys:
3369 ? - print current values og the CPM Timer registers
3370 b - enable interrupts and start timer
3371 e - stop timer and disable interrupts
3372 q - quit application
3375 ## Ready for S-Record download ...
3376 ~>examples/timer.srec
3377 1 2 3 4 5 6 7 8 9 10 11 ...
3378 [file transfer complete]
3380 ## Start Addr = 0x00040004
3383 ## Starting application at 0x00040004 ...
3386 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3389 [q, b, e, ?] Set interval 1000000 us
3392 [q, b, e, ?] ........
3393 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3396 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3399 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3402 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3404 [q, b, e, ?] ...Stopping timer
3406 [q, b, e, ?] ## Application terminated, rc = 0x0
3412 Over time, many people have reported problems when trying to use the
3413 "minicom" terminal emulation program for serial download. I (wd)
3414 consider minicom to be broken, and recommend not to use it. Under
3415 Unix, I recommend to use C-Kermit for general purpose use (and
3416 especially for kermit binary protocol download ("loadb" command), and
3417 use "cu" for S-Record download ("loads" command).
3419 Nevertheless, if you absolutely want to use it try adding this
3420 configuration to your "File transfer protocols" section:
3422 Name Program Name U/D FullScr IO-Red. Multi
3423 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3424 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3430 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3431 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3433 Building requires a cross environment; it is known to work on
3434 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3435 need gmake since the Makefiles are not compatible with BSD make).
3436 Note that the cross-powerpc package does not install include files;
3437 attempting to build U-Boot will fail because <machine/ansi.h> is
3438 missing. This file has to be installed and patched manually:
3440 # cd /usr/pkg/cross/powerpc-netbsd/include
3442 # ln -s powerpc machine
3443 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3444 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3446 Native builds *don't* work due to incompatibilities between native
3447 and U-Boot include files.
3449 Booting assumes that (the first part of) the image booted is a
3450 stage-2 loader which in turn loads and then invokes the kernel
3451 proper. Loader sources will eventually appear in the NetBSD source
3452 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3453 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3456 Implementation Internals:
3457 =========================
3459 The following is not intended to be a complete description of every
3460 implementation detail. However, it should help to understand the
3461 inner workings of U-Boot and make it easier to port it to custom
3465 Initial Stack, Global Data:
3466 ---------------------------
3468 The implementation of U-Boot is complicated by the fact that U-Boot
3469 starts running out of ROM (flash memory), usually without access to
3470 system RAM (because the memory controller is not initialized yet).
3471 This means that we don't have writable Data or BSS segments, and BSS
3472 is not initialized as zero. To be able to get a C environment working
3473 at all, we have to allocate at least a minimal stack. Implementation
3474 options for this are defined and restricted by the CPU used: Some CPU
3475 models provide on-chip memory (like the IMMR area on MPC8xx and
3476 MPC826x processors), on others (parts of) the data cache can be
3477 locked as (mis-) used as memory, etc.
3479 Chris Hallinan posted a good summary of these issues to the
3480 u-boot-users mailing list:
3482 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3483 From: "Chris Hallinan" <clh@net1plus.com>
3484 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3487 Correct me if I'm wrong, folks, but the way I understand it
3488 is this: Using DCACHE as initial RAM for Stack, etc, does not
3489 require any physical RAM backing up the cache. The cleverness
3490 is that the cache is being used as a temporary supply of
3491 necessary storage before the SDRAM controller is setup. It's
3492 beyond the scope of this list to expain the details, but you
3493 can see how this works by studying the cache architecture and
3494 operation in the architecture and processor-specific manuals.
3496 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3497 is another option for the system designer to use as an
3498 initial stack/ram area prior to SDRAM being available. Either
3499 option should work for you. Using CS 4 should be fine if your
3500 board designers haven't used it for something that would
3501 cause you grief during the initial boot! It is frequently not
3504 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3505 with your processor/board/system design. The default value
3506 you will find in any recent u-boot distribution in
3507 walnut.h should work for you. I'd set it to a value larger
3508 than your SDRAM module. If you have a 64MB SDRAM module, set
3509 it above 400_0000. Just make sure your board has no resources
3510 that are supposed to respond to that address! That code in
3511 start.S has been around a while and should work as is when
3512 you get the config right.
3517 It is essential to remember this, since it has some impact on the C
3518 code for the initialization procedures:
3520 * Initialized global data (data segment) is read-only. Do not attempt
3523 * Do not use any unitialized global data (or implicitely initialized
3524 as zero data - BSS segment) at all - this is undefined, initiali-
3525 zation is performed later (when relocating to RAM).
3527 * Stack space is very limited. Avoid big data buffers or things like
3530 Having only the stack as writable memory limits means we cannot use
3531 normal global data to share information beween the code. But it
3532 turned out that the implementation of U-Boot can be greatly
3533 simplified by making a global data structure (gd_t) available to all
3534 functions. We could pass a pointer to this data as argument to _all_
3535 functions, but this would bloat the code. Instead we use a feature of
3536 the GCC compiler (Global Register Variables) to share the data: we
3537 place a pointer (gd) to the global data into a register which we
3538 reserve for this purpose.
3540 When choosing a register for such a purpose we are restricted by the
3541 relevant (E)ABI specifications for the current architecture, and by
3542 GCC's implementation.
3544 For PowerPC, the following registers have specific use:
3547 R3-R4: parameter passing and return values
3548 R5-R10: parameter passing
3549 R13: small data area pointer
3553 (U-Boot also uses R14 as internal GOT pointer.)
3555 ==> U-Boot will use R29 to hold a pointer to the global data
3557 Note: on PPC, we could use a static initializer (since the
3558 address of the global data structure is known at compile time),
3559 but it turned out that reserving a register results in somewhat
3560 smaller code - although the code savings are not that big (on
3561 average for all boards 752 bytes for the whole U-Boot image,
3562 624 text + 127 data).
3564 On ARM, the following registers are used:
3566 R0: function argument word/integer result
3567 R1-R3: function argument word
3569 R10: stack limit (used only if stack checking if enabled)
3570 R11: argument (frame) pointer
3571 R12: temporary workspace
3574 R15: program counter
3576 ==> U-Boot will use R8 to hold a pointer to the global data
3578 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3579 or current versions of GCC may "optimize" the code too much.
3584 U-Boot runs in system state and uses physical addresses, i.e. the
3585 MMU is not used either for address mapping nor for memory protection.
3587 The available memory is mapped to fixed addresses using the memory
3588 controller. In this process, a contiguous block is formed for each
3589 memory type (Flash, SDRAM, SRAM), even when it consists of several
3590 physical memory banks.
3592 U-Boot is installed in the first 128 kB of the first Flash bank (on
3593 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3594 booting and sizing and initializing DRAM, the code relocates itself
3595 to the upper end of DRAM. Immediately below the U-Boot code some
3596 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3597 configuration setting]. Below that, a structure with global Board
3598 Info data is placed, followed by the stack (growing downward).
3600 Additionally, some exception handler code is copied to the low 8 kB
3601 of DRAM (0x00000000 ... 0x00001FFF).
3603 So a typical memory configuration with 16 MB of DRAM could look like
3606 0x0000 0000 Exception Vector code
3609 0x0000 2000 Free for Application Use
3615 0x00FB FF20 Monitor Stack (Growing downward)
3616 0x00FB FFAC Board Info Data and permanent copy of global data
3617 0x00FC 0000 Malloc Arena
3620 0x00FE 0000 RAM Copy of Monitor Code
3621 ... eventually: LCD or video framebuffer
3622 ... eventually: pRAM (Protected RAM - unchanged by reset)
3623 0x00FF FFFF [End of RAM]
3626 System Initialization:
3627 ----------------------
3629 In the reset configuration, U-Boot starts at the reset entry point
3630 (on most PowerPC systens at address 0x00000100). Because of the reset
3631 configuration for CS0# this is a mirror of the onboard Flash memory.
3632 To be able to re-map memory U-Boot then jumps to its link address.
3633 To be able to implement the initialization code in C, a (small!)
3634 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3635 which provide such a feature like MPC8xx or MPC8260), or in a locked
3636 part of the data cache. After that, U-Boot initializes the CPU core,
3637 the caches and the SIU.
3639 Next, all (potentially) available memory banks are mapped using a
3640 preliminary mapping. For example, we put them on 512 MB boundaries
3641 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3642 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3643 programmed for SDRAM access. Using the temporary configuration, a
3644 simple memory test is run that determines the size of the SDRAM
3647 When there is more than one SDRAM bank, and the banks are of
3648 different size, the largest is mapped first. For equal size, the first
3649 bank (CS2#) is mapped first. The first mapping is always for address
3650 0x00000000, with any additional banks following immediately to create
3651 contiguous memory starting from 0.
3653 Then, the monitor installs itself at the upper end of the SDRAM area
3654 and allocates memory for use by malloc() and for the global Board
3655 Info data; also, the exception vector code is copied to the low RAM
3656 pages, and the final stack is set up.
3658 Only after this relocation will you have a "normal" C environment;
3659 until that you are restricted in several ways, mostly because you are
3660 running from ROM, and because the code will have to be relocated to a
3664 U-Boot Porting Guide:
3665 ----------------------
3667 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3671 int main (int argc, char *argv[])
3673 sighandler_t no_more_time;
3675 signal (SIGALRM, no_more_time);
3676 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3678 if (available_money > available_manpower) {
3679 pay consultant to port U-Boot;
3683 Download latest U-Boot source;
3685 Subscribe to u-boot-users mailing list;
3688 email ("Hi, I am new to U-Boot, how do I get started?");
3692 Read the README file in the top level directory;
3693 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3694 Read the source, Luke;
3697 if (available_money > toLocalCurrency ($2500)) {
3700 Add a lot of aggravation and time;
3703 Create your own board support subdirectory;
3705 Create your own board config file;
3709 Add / modify source code;
3713 email ("Hi, I am having problems...");
3715 Send patch file to Wolfgang;
3720 void no_more_time (int sig)
3729 All contributions to U-Boot should conform to the Linux kernel
3730 coding style; see the file "Documentation/CodingStyle" and the script
3731 "scripts/Lindent" in your Linux kernel source directory. In sources
3732 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3733 spaces before parameters to function calls) is actually used.
3735 Source files originating from a different project (for example the
3736 MTD subsystem) are generally exempt from these guidelines and are not
3737 reformated to ease subsequent migration to newer versions of those
3740 Please note that U-Boot is implemented in C (and to some small parts in
3741 Assembler); no C++ is used, so please do not use C++ style comments (//)
3744 Please also stick to the following formatting rules:
3745 - remove any trailing white space
3746 - use TAB characters for indentation, not spaces
3747 - make sure NOT to use DOS '\r\n' line feeds
3748 - do not add more than 2 empty lines to source files
3749 - do not add trailing empty lines to source files
3751 Submissions which do not conform to the standards may be returned
3752 with a request to reformat the changes.
3758 Since the number of patches for U-Boot is growing, we need to
3759 establish some rules. Submissions which do not conform to these rules
3760 may be rejected, even when they contain important and valuable stuff.
3762 Patches shall be sent to the u-boot-users mailing list.
3764 When you send a patch, please include the following information with
3767 * For bug fixes: a description of the bug and how your patch fixes
3768 this bug. Please try to include a way of demonstrating that the
3769 patch actually fixes something.
3771 * For new features: a description of the feature and your
3774 * A CHANGELOG entry as plaintext (separate from the patch)
3776 * For major contributions, your entry to the CREDITS file
3778 * When you add support for a new board, don't forget to add this
3779 board to the MAKEALL script, too.
3781 * If your patch adds new configuration options, don't forget to
3782 document these in the README file.
3784 * The patch itself. If you are accessing the CVS repository use "cvs
3785 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3786 version of diff does not support these options, then get the latest
3787 version of GNU diff.
3789 The current directory when running this command shall be the top
3790 level directory of the U-Boot source tree, or it's parent directory
3791 (i. e. please make sure that your patch includes sufficient
3792 directory information for the affected files).
3794 We accept patches as plain text, MIME attachments or as uuencoded
3797 * If one logical set of modifications affects or creates several
3798 files, all these changes shall be submitted in a SINGLE patch file.
3800 * Changesets that contain different, unrelated modifications shall be
3801 submitted as SEPARATE patches, one patch per changeset.
3806 * Before sending the patch, run the MAKEALL script on your patched
3807 source tree and make sure that no errors or warnings are reported
3808 for any of the boards.
3810 * Keep your modifications to the necessary minimum: A patch
3811 containing several unrelated changes or arbitrary reformats will be
3812 returned with a request to re-formatting / split it.
3814 * If you modify existing code, make sure that your new code does not
3815 add to the memory footprint of the code ;-) Small is beautiful!
3816 When adding new features, these should compile conditionally only
3817 (using #ifdef), and the resulting code with the new feature
3818 disabled must not need more memory than the old code without your
3821 * Remember that there is a size limit of 40 kB per message on the
3822 u-boot-users mailing list. Compression may help.
projects / u-boot / blob