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 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
140 - mips Files specific to MIPS CPUs
141 - mpc5xx Files specific to Freescale MPC5xx CPUs
142 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
143 - mpc8xx Files specific to Freescale MPC8xx CPUs
144 - mpc8220 Files specific to Freescale MPC8220 CPUs
145 - mpc824x Files specific to Freescale MPC824x CPUs
146 - mpc8260 Files specific to Freescale MPC8260 CPUs
147 - mpc85xx Files specific to Freescale MPC85xx CPUs
148 - nios Files specific to Altera NIOS CPUs
149 - nios2 Files specific to Altera Nios-II CPUs
150 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
151 - pxa Files specific to Intel XScale PXA CPUs
152 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
153 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
154 - disk Code for disk drive partition handling
155 - doc Documentation (don't expect too much)
156 - drivers Commonly used device drivers
157 - dtt Digital Thermometer and Thermostat drivers
158 - examples Example code for standalone applications, etc.
159 - include Header Files
160 - lib_arm Files generic to ARM architecture
161 - lib_avr32 Files generic to AVR32 architecture
162 - lib_generic Files generic to all architectures
163 - lib_i386 Files generic to i386 architecture
164 - lib_m68k Files generic to m68k architecture
165 - lib_mips Files generic to MIPS architecture
166 - lib_nios Files generic to NIOS architecture
167 - lib_ppc Files generic to PowerPC architecture
168 - libfdt Library files to support flattened device trees
169 - net Networking code
170 - post Power On Self Test
171 - rtc Real Time Clock drivers
172 - tools Tools to build S-Record or U-Boot images, etc.
174 Software Configuration:
175 =======================
177 Configuration is usually done using C preprocessor defines; the
178 rationale behind that is to avoid dead code whenever possible.
180 There are two classes of configuration variables:
182 * Configuration _OPTIONS_:
183 These are selectable by the user and have names beginning with
186 * Configuration _SETTINGS_:
187 These depend on the hardware etc. and should not be meddled with if
188 you don't know what you're doing; they have names beginning with
191 Later we will add a configuration tool - probably similar to or even
192 identical to what's used for the Linux kernel. Right now, we have to
193 do the configuration by hand, which means creating some symbolic
194 links and editing some configuration files. We use the TQM8xxL boards
198 Selection of Processor Architecture and Board Type:
199 ---------------------------------------------------
201 For all supported boards there are ready-to-use default
202 configurations available; just type "make <board_name>_config".
204 Example: For a TQM823L module type:
209 For the Cogent platform, you need to specify the cpu type as well;
210 e.g. "make cogent_mpc8xx_config". And also configure the cogent
211 directory according to the instructions in cogent/README.
214 Configuration Options:
215 ----------------------
217 Configuration depends on the combination of board and CPU type; all
218 such information is kept in a configuration file
219 "include/configs/<board_name>.h".
221 Example: For a TQM823L module, all configuration settings are in
222 "include/configs/TQM823L.h".
225 Many of the options are named exactly as the corresponding Linux
226 kernel configuration options. The intention is to make it easier to
227 build a config tool - later.
230 The following options need to be configured:
232 - CPU Type: Define exactly one of
236 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
239 or CONFIG_MPC824X, CONFIG_MPC8260
259 MicroBlaze based CPUs:
260 ----------------------
264 ----------------------
268 ----------------------
271 - Board Type: Define exactly one of
273 PowerPC based boards:
274 ---------------------
276 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
277 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
278 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
279 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
280 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
281 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
282 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
283 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
284 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
285 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
286 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
287 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
288 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
289 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
290 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
291 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
292 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
293 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
294 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
295 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
296 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
297 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
298 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
299 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
300 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
301 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
302 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
303 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
304 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
305 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
306 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
307 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
308 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
309 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
310 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
311 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
312 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
313 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
318 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
319 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
320 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
321 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
322 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
323 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
324 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
325 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
328 MicroBlaze based boards:
329 ------------------------
334 ------------------------
336 CONFIG_PCI5441 CONFIG_PK1C20
337 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
344 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
345 Define exactly one of
349 - CPU Module Type: (if CONFIG_COGENT is defined)
350 Define exactly one of
352 --- FIXME --- not tested yet:
353 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
354 CONFIG_CMA287_23, CONFIG_CMA287_50
356 - Motherboard Type: (if CONFIG_COGENT is defined)
357 Define exactly one of
358 CONFIG_CMA101, CONFIG_CMA102
360 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
361 Define one or more of
364 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
365 Define one or more of
366 CONFIG_LCD_HEARTBEAT - update a character position on
367 the lcd display every second with
370 - Board flavour: (if CONFIG_MPC8260ADS is defined)
373 CFG_8260ADS - original MPC8260ADS
374 CFG_8266ADS - MPC8266ADS
375 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
376 CFG_8272ADS - MPC8272ADS
378 - MPC824X Family Member (if CONFIG_MPC824X is defined)
379 Define exactly one of
380 CONFIG_MPC8240, CONFIG_MPC8245
382 - 8xx CPU Options: (if using an MPC8xx cpu)
383 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
384 get_gclk_freq() cannot work
385 e.g. if there is no 32KHz
386 reference PIT/RTC clock
387 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
390 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
393 CONFIG_8xx_CPUCLK_DEFAULT
394 See doc/README.MPC866
398 Define this to measure the actual CPU clock instead
399 of relying on the correctness of the configured
400 values. Mostly useful for board bringup to make sure
401 the PLL is locked at the intended frequency. Note
402 that this requires a (stable) reference clock (32 kHz
403 RTC clock or CFG_8XX_XIN)
405 - Intel Monahans options:
406 CFG_MONAHANS_RUN_MODE_OSC_RATIO
408 Defines the Monahans run mode to oscillator
409 ratio. Valid values are 8, 16, 24, 31. The core
410 frequency is this value multiplied by 13 MHz.
412 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
414 Defines the Monahans turbo mode to oscillator
415 ratio. Valid values are 1 (default if undefined) and
416 2. The core frequency as calculated above is multiplied
419 - Linux Kernel Interface:
422 U-Boot stores all clock information in Hz
423 internally. For binary compatibility with older Linux
424 kernels (which expect the clocks passed in the
425 bd_info data to be in MHz) the environment variable
426 "clocks_in_mhz" can be defined so that U-Boot
427 converts clock data to MHZ before passing it to the
429 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
430 "clocks_in_mhz=1" is automatically included in the
433 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
435 When transfering memsize parameter to linux, some versions
436 expect it to be in bytes, others in MB.
437 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
439 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
441 New kernel versions are expecting firmware settings to be
442 passed using flattened device trees (based on open firmware
446 * New libfdt-based support
447 * Adds the "fdt" command
448 * The bootm command does _not_ modify the fdt
451 * Deprecated, see CONFIG_OF_LIBFDT
452 * Original ft_build.c-based support
453 * Automatically modifies the dft as part of the bootm command
454 * The environment variable "disable_of", when set,
455 disables this functionality.
457 CONFIG_OF_FLAT_TREE_MAX_SIZE
459 The maximum size of the constructed OF tree.
461 OF_CPU - The proper name of the cpus node.
462 OF_SOC - The proper name of the soc node.
463 OF_TBCLK - The timebase frequency.
464 OF_STDOUT_PATH - The path to the console device
468 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
469 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
470 will have a copy of the bd_t. Space should be
471 pre-allocated in the dts for the bd_t.
473 CONFIG_OF_HAS_UBOOT_ENV
475 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
476 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
477 will have a copy of u-boot's environment variables
479 CONFIG_OF_BOARD_SETUP
481 Board code has addition modification that it wants to make
482 to the flat device tree before handing it off to the kernel
486 This define fills in the correct boot cpu in the boot
487 param header, the default value is zero if undefined.
492 Define this if you want support for Amba PrimeCell PL010 UARTs.
496 Define this if you want support for Amba PrimeCell PL011 UARTs.
500 If you have Amba PrimeCell PL011 UARTs, set this variable to
501 the clock speed of the UARTs.
505 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
506 define this to a list of base addresses for each (supported)
507 port. See e.g. include/configs/versatile.h
511 Depending on board, define exactly one serial port
512 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
513 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
514 console by defining CONFIG_8xx_CONS_NONE
516 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
517 port routines must be defined elsewhere
518 (i.e. serial_init(), serial_getc(), ...)
521 Enables console device for a color framebuffer. Needs following
522 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
523 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
525 VIDEO_HW_RECTFILL graphic chip supports
528 VIDEO_HW_BITBLT graphic chip supports
529 bit-blit (cf. smiLynxEM)
530 VIDEO_VISIBLE_COLS visible pixel columns
532 VIDEO_VISIBLE_ROWS visible pixel rows
533 VIDEO_PIXEL_SIZE bytes per pixel
534 VIDEO_DATA_FORMAT graphic data format
535 (0-5, cf. cfb_console.c)
536 VIDEO_FB_ADRS framebuffer address
537 VIDEO_KBD_INIT_FCT keyboard int fct
538 (i.e. i8042_kbd_init())
539 VIDEO_TSTC_FCT test char fct
541 VIDEO_GETC_FCT get char fct
543 CONFIG_CONSOLE_CURSOR cursor drawing on/off
544 (requires blink timer
546 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
547 CONFIG_CONSOLE_TIME display time/date info in
549 (requires CFG_CMD_DATE)
550 CONFIG_VIDEO_LOGO display Linux logo in
552 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
553 linux_logo.h for logo.
554 Requires CONFIG_VIDEO_LOGO
555 CONFIG_CONSOLE_EXTRA_INFO
556 addional board info beside
559 When CONFIG_CFB_CONSOLE is defined, video console is
560 default i/o. Serial console can be forced with
561 environment 'console=serial'.
563 When CONFIG_SILENT_CONSOLE is defined, all console
564 messages (by U-Boot and Linux!) can be silenced with
565 the "silent" environment variable. See
566 doc/README.silent for more information.
569 CONFIG_BAUDRATE - in bps
570 Select one of the baudrates listed in
571 CFG_BAUDRATE_TABLE, see below.
572 CFG_BRGCLK_PRESCALE, baudrate prescale
574 - Interrupt driven serial port input:
575 CONFIG_SERIAL_SOFTWARE_FIFO
578 Use an interrupt handler for receiving data on the
579 serial port. It also enables using hardware handshake
580 (RTS/CTS) and UART's built-in FIFO. Set the number of
581 bytes the interrupt driven input buffer should have.
583 Leave undefined to disable this feature, including
584 disable the buffer and hardware handshake.
586 - Console UART Number:
590 If defined internal UART1 (and not UART0) is used
591 as default U-Boot console.
593 - Boot Delay: CONFIG_BOOTDELAY - in seconds
594 Delay before automatically booting the default image;
595 set to -1 to disable autoboot.
597 See doc/README.autoboot for these options that
598 work with CONFIG_BOOTDELAY. None are required.
599 CONFIG_BOOT_RETRY_TIME
600 CONFIG_BOOT_RETRY_MIN
601 CONFIG_AUTOBOOT_KEYED
602 CONFIG_AUTOBOOT_PROMPT
603 CONFIG_AUTOBOOT_DELAY_STR
604 CONFIG_AUTOBOOT_STOP_STR
605 CONFIG_AUTOBOOT_DELAY_STR2
606 CONFIG_AUTOBOOT_STOP_STR2
607 CONFIG_ZERO_BOOTDELAY_CHECK
608 CONFIG_RESET_TO_RETRY
612 Only needed when CONFIG_BOOTDELAY is enabled;
613 define a command string that is automatically executed
614 when no character is read on the console interface
615 within "Boot Delay" after reset.
618 This can be used to pass arguments to the bootm
619 command. The value of CONFIG_BOOTARGS goes into the
620 environment value "bootargs".
622 CONFIG_RAMBOOT and CONFIG_NFSBOOT
623 The value of these goes into the environment as
624 "ramboot" and "nfsboot" respectively, and can be used
625 as a convenience, when switching between booting from
631 When this option is #defined, the existence of the
632 environment variable "preboot" will be checked
633 immediately before starting the CONFIG_BOOTDELAY
634 countdown and/or running the auto-boot command resp.
635 entering interactive mode.
637 This feature is especially useful when "preboot" is
638 automatically generated or modified. For an example
639 see the LWMON board specific code: here "preboot" is
640 modified when the user holds down a certain
641 combination of keys on the (special) keyboard when
644 - Serial Download Echo Mode:
646 If defined to 1, all characters received during a
647 serial download (using the "loads" command) are
648 echoed back. This might be needed by some terminal
649 emulations (like "cu"), but may as well just take
650 time on others. This setting #define's the initial
651 value of the "loads_echo" environment variable.
653 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
655 Select one of the baudrates listed in
656 CFG_BAUDRATE_TABLE, see below.
660 Most monitor functions can be selected (or
661 de-selected) by adjusting the definition of
662 CONFIG_COMMANDS; to select individual functions,
663 #define CONFIG_COMMANDS by "OR"ing any of the
666 #define enables commands:
667 -------------------------
668 CFG_CMD_ASKENV * ask for env variable
669 CFG_CMD_AUTOSCRIPT Autoscript Support
671 CFG_CMD_BEDBUG * Include BedBug Debugger
672 CFG_CMD_BMP * BMP support
673 CFG_CMD_BSP * Board specific commands
675 CFG_CMD_CACHE * icache, dcache
676 CFG_CMD_CONSOLE coninfo
677 CFG_CMD_DATE * support for RTC, date/time...
678 CFG_CMD_DHCP * DHCP support
679 CFG_CMD_DIAG * Diagnostics
680 CFG_CMD_DOC * Disk-On-Chip Support
681 CFG_CMD_DTT * Digital Therm and Thermostat
682 CFG_CMD_ECHO echo arguments
683 CFG_CMD_EEPROM * EEPROM read/write support
684 CFG_CMD_ELF * bootelf, bootvx
686 CFG_CMD_FDC * Floppy Disk Support
687 CFG_CMD_FAT * FAT partition support
688 CFG_CMD_FDOS * Dos diskette Support
689 CFG_CMD_FLASH flinfo, erase, protect
690 CFG_CMD_FPGA FPGA device initialization support
691 CFG_CMD_HWFLOW * RTS/CTS hw flow control
692 CFG_CMD_I2C * I2C serial bus support
693 CFG_CMD_IDE * IDE harddisk support
695 CFG_CMD_IMLS List all found images
696 CFG_CMD_IMMAP * IMMR dump support
697 CFG_CMD_IRQ * irqinfo
698 CFG_CMD_ITEST Integer/string test of 2 values
699 CFG_CMD_JFFS2 * JFFS2 Support
703 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
705 CFG_CMD_MISC Misc functions like sleep etc
706 CFG_CMD_MMC * MMC memory mapped support
707 CFG_CMD_MII * MII utility commands
708 CFG_CMD_NAND * NAND support
709 CFG_CMD_NET bootp, tftpboot, rarpboot
710 CFG_CMD_PCI * pciinfo
711 CFG_CMD_PCMCIA * PCMCIA support
712 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
713 CFG_CMD_PORTIO * Port I/O
714 CFG_CMD_REGINFO * Register dump
715 CFG_CMD_RUN run command in env variable
716 CFG_CMD_SAVES * save S record dump
717 CFG_CMD_SCSI * SCSI Support
718 CFG_CMD_SDRAM * print SDRAM configuration information
719 (requires CFG_CMD_I2C)
720 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
721 CFG_CMD_SPI * SPI serial bus support
722 CFG_CMD_USB * USB support
723 CFG_CMD_VFD * VFD support (TRAB)
724 CFG_CMD_BSP * Board SPecific functions
725 CFG_CMD_CDP * Cisco Discover Protocol support
726 CFG_CMD_FSL * Microblaze FSL support
727 -----------------------------------------------
730 CONFIG_CMD_DFL Default configuration; at the moment
731 this is includes all commands, except
732 the ones marked with "*" in the list
735 If you don't define CONFIG_COMMANDS it defaults to
736 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
737 override the default settings in the respective
740 EXAMPLE: If you want all functions except of network
741 support you can write:
743 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
746 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
748 Note: Don't enable the "icache" and "dcache" commands
749 (configuration option CFG_CMD_CACHE) unless you know
750 what you (and your U-Boot users) are doing. Data
751 cache cannot be enabled on systems like the 8xx or
752 8260 (where accesses to the IMMR region must be
753 uncached), and it cannot be disabled on all other
754 systems where we (mis-) use the data cache to hold an
755 initial stack and some data.
758 XXX - this list needs to get updated!
762 If this variable is defined, it enables watchdog
763 support. There must be support in the platform specific
764 code for a watchdog. For the 8xx and 8260 CPUs, the
765 SIU Watchdog feature is enabled in the SYPCR
769 CONFIG_VERSION_VARIABLE
770 If this variable is defined, an environment variable
771 named "ver" is created by U-Boot showing the U-Boot
772 version as printed by the "version" command.
773 This variable is readonly.
777 When CFG_CMD_DATE is selected, the type of the RTC
778 has to be selected, too. Define exactly one of the
781 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
782 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
783 CONFIG_RTC_MC146818 - use MC146818 RTC
784 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
785 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
786 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
787 CONFIG_RTC_DS164x - use Dallas DS164x RTC
788 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
790 Note that if the RTC uses I2C, then the I2C interface
791 must also be configured. See I2C Support, below.
795 When CONFIG_TIMESTAMP is selected, the timestamp
796 (date and time) of an image is printed by image
797 commands like bootm or iminfo. This option is
798 automatically enabled when you select CFG_CMD_DATE .
801 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
802 and/or CONFIG_ISO_PARTITION
804 If IDE or SCSI support is enabled (CFG_CMD_IDE or
805 CFG_CMD_SCSI) you must configure support for at least
806 one partition type as well.
809 CONFIG_IDE_RESET_ROUTINE - this is defined in several
810 board configurations files but used nowhere!
812 CONFIG_IDE_RESET - is this is defined, IDE Reset will
813 be performed by calling the function
814 ide_set_reset(int reset)
815 which has to be defined in a board specific file
820 Set this to enable ATAPI support.
825 Set this to enable support for disks larger than 137GB
826 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
827 Whithout these , LBA48 support uses 32bit variables and will 'only'
828 support disks up to 2.1TB.
831 When enabled, makes the IDE subsystem use 64bit sector addresses.
835 At the moment only there is only support for the
836 SYM53C8XX SCSI controller; define
837 CONFIG_SCSI_SYM53C8XX to enable it.
839 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
840 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
841 CFG_SCSI_MAX_LUN] can be adjusted to define the
842 maximum numbers of LUNs, SCSI ID's and target
844 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
846 - NETWORK Support (PCI):
848 Support for Intel 8254x gigabit chips.
851 Support for Intel 82557/82559/82559ER chips.
852 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
853 write routine for first time initialisation.
856 Support for Digital 2114x chips.
857 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
858 modem chip initialisation (KS8761/QS6611).
861 Support for National dp83815 chips.
864 Support for National dp8382[01] gigabit chips.
866 - NETWORK Support (other):
868 CONFIG_DRIVER_LAN91C96
869 Support for SMSC's LAN91C96 chips.
872 Define this to hold the physical address
873 of the LAN91C96's I/O space
875 CONFIG_LAN91C96_USE_32_BIT
876 Define this to enable 32 bit addressing
878 CONFIG_DRIVER_SMC91111
879 Support for SMSC's LAN91C111 chip
882 Define this to hold the physical address
883 of the device (I/O space)
885 CONFIG_SMC_USE_32_BIT
886 Define this if data bus is 32 bits
888 CONFIG_SMC_USE_IOFUNCS
889 Define this to use i/o functions instead of macros
890 (some hardware wont work with macros)
893 At the moment only the UHCI host controller is
894 supported (PIP405, MIP405, MPC5200); define
895 CONFIG_USB_UHCI to enable it.
896 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
897 and define CONFIG_USB_STORAGE to enable the USB
900 Supported are USB Keyboards and USB Floppy drives
902 MPC5200 USB requires additional defines:
904 for 528 MHz Clock: 0x0001bbbb
906 for differential drivers: 0x00001000
907 for single ended drivers: 0x00005000
911 The MMC controller on the Intel PXA is supported. To
912 enable this define CONFIG_MMC. The MMC can be
913 accessed from the boot prompt by mapping the device
914 to physical memory similar to flash. Command line is
915 enabled with CFG_CMD_MMC. The MMC driver also works with
916 the FAT fs. This is enabled with CFG_CMD_FAT.
918 - Journaling Flash filesystem support:
919 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
920 CONFIG_JFFS2_NAND_DEV
921 Define these for a default partition on a NAND device
923 CFG_JFFS2_FIRST_SECTOR,
924 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
925 Define these for a default partition on a NOR device
928 Define this to create an own partition. You have to provide a
929 function struct part_info* jffs2_part_info(int part_num)
931 If you define only one JFFS2 partition you may also want to
932 #define CFG_JFFS_SINGLE_PART 1
933 to disable the command chpart. This is the default when you
934 have not defined a custom partition
939 Define this to enable standard (PC-Style) keyboard
943 Standard PC keyboard driver with US (is default) and
944 GERMAN key layout (switch via environment 'keymap=de') support.
945 Export function i8042_kbd_init, i8042_tstc and i8042_getc
946 for cfb_console. Supports cursor blinking.
951 Define this to enable video support (for output to
956 Enable Chips & Technologies 69000 Video chip
958 CONFIG_VIDEO_SMI_LYNXEM
959 Enable Silicon Motion SMI 712/710/810 Video chip. The
960 video output is selected via environment 'videoout'
961 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
964 For the CT69000 and SMI_LYNXEM drivers, videomode is
965 selected via environment 'videomode'. Two diferent ways
967 - "videomode=num" 'num' is a standard LiLo mode numbers.
968 Following standard modes are supported (* is default):
970 Colors 640x480 800x600 1024x768 1152x864 1280x1024
971 -------------+---------------------------------------------
972 8 bits | 0x301* 0x303 0x305 0x161 0x307
973 15 bits | 0x310 0x313 0x316 0x162 0x319
974 16 bits | 0x311 0x314 0x317 0x163 0x31A
975 24 bits | 0x312 0x315 0x318 ? 0x31B
976 -------------+---------------------------------------------
977 (i.e. setenv videomode 317; saveenv; reset;)
979 - "videomode=bootargs" all the video parameters are parsed
980 from the bootargs. (See drivers/videomodes.c)
983 CONFIG_VIDEO_SED13806
984 Enable Epson SED13806 driver. This driver supports 8bpp
985 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
986 or CONFIG_VIDEO_SED13806_16BPP
991 Define this to enable a custom keyboard support.
992 This simply calls drv_keyboard_init() which must be
993 defined in your board-specific files.
994 The only board using this so far is RBC823.
996 - LCD Support: CONFIG_LCD
998 Define this to enable LCD support (for output to LCD
999 display); also select one of the supported displays
1000 by defining one of these:
1002 CONFIG_NEC_NL6448AC33:
1004 NEC NL6448AC33-18. Active, color, single scan.
1006 CONFIG_NEC_NL6448BC20
1008 NEC NL6448BC20-08. 6.5", 640x480.
1009 Active, color, single scan.
1011 CONFIG_NEC_NL6448BC33_54
1013 NEC NL6448BC33-54. 10.4", 640x480.
1014 Active, color, single scan.
1018 Sharp 320x240. Active, color, single scan.
1019 It isn't 16x9, and I am not sure what it is.
1021 CONFIG_SHARP_LQ64D341
1023 Sharp LQ64D341 display, 640x480.
1024 Active, color, single scan.
1028 HLD1045 display, 640x480.
1029 Active, color, single scan.
1033 Optrex CBL50840-2 NF-FW 99 22 M5
1035 Hitachi LMG6912RPFC-00T
1039 320x240. Black & white.
1041 Normally display is black on white background; define
1042 CFG_WHITE_ON_BLACK to get it inverted.
1044 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1046 If this option is set, the environment is checked for
1047 a variable "splashimage". If found, the usual display
1048 of logo, copyright and system information on the LCD
1049 is suppressed and the BMP image at the address
1050 specified in "splashimage" is loaded instead. The
1051 console is redirected to the "nulldev", too. This
1052 allows for a "silent" boot where a splash screen is
1053 loaded very quickly after power-on.
1055 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1057 If this option is set, additionally to standard BMP
1058 images, gzipped BMP images can be displayed via the
1059 splashscreen support or the bmp command.
1061 - Compression support:
1064 If this option is set, support for bzip2 compressed
1065 images is included. If not, only uncompressed and gzip
1066 compressed images are supported.
1068 NOTE: the bzip2 algorithm requires a lot of RAM, so
1069 the malloc area (as defined by CFG_MALLOC_LEN) should
1075 The address of PHY on MII bus.
1077 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1079 The clock frequency of the MII bus
1083 If this option is set, support for speed/duplex
1084 detection of Gigabit PHY is included.
1086 CONFIG_PHY_RESET_DELAY
1088 Some PHY like Intel LXT971A need extra delay after
1089 reset before any MII register access is possible.
1090 For such PHY, set this option to the usec delay
1091 required. (minimum 300usec for LXT971A)
1093 CONFIG_PHY_CMD_DELAY (ppc4xx)
1095 Some PHY like Intel LXT971A need extra delay after
1096 command issued before MII status register can be read
1103 Define a default value for ethernet address to use
1104 for the respective ethernet interface, in case this
1105 is not determined automatically.
1110 Define a default value for the IP address to use for
1111 the default ethernet interface, in case this is not
1112 determined through e.g. bootp.
1114 - Server IP address:
1117 Defines a default value for theIP address of a TFTP
1118 server to contact when using the "tftboot" command.
1120 - BOOTP Recovery Mode:
1121 CONFIG_BOOTP_RANDOM_DELAY
1123 If you have many targets in a network that try to
1124 boot using BOOTP, you may want to avoid that all
1125 systems send out BOOTP requests at precisely the same
1126 moment (which would happen for instance at recovery
1127 from a power failure, when all systems will try to
1128 boot, thus flooding the BOOTP server. Defining
1129 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1130 inserted before sending out BOOTP requests. The
1131 following delays are insterted then:
1133 1st BOOTP request: delay 0 ... 1 sec
1134 2nd BOOTP request: delay 0 ... 2 sec
1135 3rd BOOTP request: delay 0 ... 4 sec
1137 BOOTP requests: delay 0 ... 8 sec
1139 - DHCP Advanced Options:
1142 You can fine tune the DHCP functionality by adding
1143 these flags to the CONFIG_BOOTP_MASK define:
1145 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1146 serverip from a DHCP server, it is possible that more
1147 than one DNS serverip is offered to the client.
1148 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1149 serverip will be stored in the additional environment
1150 variable "dnsip2". The first DNS serverip is always
1151 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1152 is added to the CONFIG_BOOTP_MASK.
1154 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1155 to do a dynamic update of a DNS server. To do this, they
1156 need the hostname of the DHCP requester.
1157 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1158 CONFIG_BOOTP_MASK, the content of the "hostname"
1159 environment variable is passed as option 12 to
1163 CONFIG_CDP_DEVICE_ID
1165 The device id used in CDP trigger frames.
1167 CONFIG_CDP_DEVICE_ID_PREFIX
1169 A two character string which is prefixed to the MAC address
1174 A printf format string which contains the ascii name of
1175 the port. Normally is set to "eth%d" which sets
1176 eth0 for the first ethernet, eth1 for the second etc.
1178 CONFIG_CDP_CAPABILITIES
1180 A 32bit integer which indicates the device capabilities;
1181 0x00000010 for a normal host which does not forwards.
1185 An ascii string containing the version of the software.
1189 An ascii string containing the name of the platform.
1193 A 32bit integer sent on the trigger.
1195 CONFIG_CDP_POWER_CONSUMPTION
1197 A 16bit integer containing the power consumption of the
1198 device in .1 of milliwatts.
1200 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1202 A byte containing the id of the VLAN.
1204 - Status LED: CONFIG_STATUS_LED
1206 Several configurations allow to display the current
1207 status using a LED. For instance, the LED will blink
1208 fast while running U-Boot code, stop blinking as
1209 soon as a reply to a BOOTP request was received, and
1210 start blinking slow once the Linux kernel is running
1211 (supported by a status LED driver in the Linux
1212 kernel). Defining CONFIG_STATUS_LED enables this
1215 - CAN Support: CONFIG_CAN_DRIVER
1217 Defining CONFIG_CAN_DRIVER enables CAN driver support
1218 on those systems that support this (optional)
1219 feature, like the TQM8xxL modules.
1221 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1223 These enable I2C serial bus commands. Defining either of
1224 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1225 include the appropriate I2C driver for the selected cpu.
1227 This will allow you to use i2c commands at the u-boot
1228 command line (as long as you set CFG_CMD_I2C in
1229 CONFIG_COMMANDS) and communicate with i2c based realtime
1230 clock chips. See common/cmd_i2c.c for a description of the
1231 command line interface.
1233 CONFIG_I2C_CMD_TREE is a recommended option that places
1234 all I2C commands under a single 'i2c' root command. The
1235 older 'imm', 'imd', 'iprobe' etc. commands are considered
1236 deprecated and may disappear in the future.
1238 CONFIG_HARD_I2C selects a hardware I2C controller.
1240 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1241 bit-banging) driver instead of CPM or similar hardware
1244 There are several other quantities that must also be
1245 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1247 In both cases you will need to define CFG_I2C_SPEED
1248 to be the frequency (in Hz) at which you wish your i2c bus
1249 to run and CFG_I2C_SLAVE to be the address of this node (ie
1250 the cpu's i2c node address).
1252 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1253 sets the cpu up as a master node and so its address should
1254 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1255 p.16-473). So, set CFG_I2C_SLAVE to 0.
1257 That's all that's required for CONFIG_HARD_I2C.
1259 If you use the software i2c interface (CONFIG_SOFT_I2C)
1260 then the following macros need to be defined (examples are
1261 from include/configs/lwmon.h):
1265 (Optional). Any commands necessary to enable the I2C
1266 controller or configure ports.
1268 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1272 (Only for MPC8260 CPU). The I/O port to use (the code
1273 assumes both bits are on the same port). Valid values
1274 are 0..3 for ports A..D.
1278 The code necessary to make the I2C data line active
1279 (driven). If the data line is open collector, this
1282 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1286 The code necessary to make the I2C data line tri-stated
1287 (inactive). If the data line is open collector, this
1290 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1294 Code that returns TRUE if the I2C data line is high,
1297 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1301 If <bit> is TRUE, sets the I2C data line high. If it
1302 is FALSE, it clears it (low).
1304 eg: #define I2C_SDA(bit) \
1305 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1306 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1310 If <bit> is TRUE, sets the I2C clock line high. If it
1311 is FALSE, it clears it (low).
1313 eg: #define I2C_SCL(bit) \
1314 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1315 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1319 This delay is invoked four times per clock cycle so this
1320 controls the rate of data transfer. The data rate thus
1321 is 1 / (I2C_DELAY * 4). Often defined to be something
1324 #define I2C_DELAY udelay(2)
1328 When a board is reset during an i2c bus transfer
1329 chips might think that the current transfer is still
1330 in progress. On some boards it is possible to access
1331 the i2c SCLK line directly, either by using the
1332 processor pin as a GPIO or by having a second pin
1333 connected to the bus. If this option is defined a
1334 custom i2c_init_board() routine in boards/xxx/board.c
1335 is run early in the boot sequence.
1337 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1339 This option enables configuration of bi_iic_fast[] flags
1340 in u-boot bd_info structure based on u-boot environment
1341 variable "i2cfast". (see also i2cfast)
1343 CONFIG_I2C_MULTI_BUS
1345 This option allows the use of multiple I2C buses, each of which
1346 must have a controller. At any point in time, only one bus is
1347 active. To switch to a different bus, use the 'i2c dev' command.
1348 Note that bus numbering is zero-based.
1352 This option specifies a list of I2C devices that will be skipped
1353 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1354 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1355 pairs. Otherwise, specify a 1D array of device addresses
1358 #undef CONFIG_I2C_MULTI_BUS
1359 #define CFG_I2C_NOPROBES {0x50,0x68}
1361 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1363 #define CONFIG_I2C_MULTI_BUS
1364 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1366 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1370 If defined, then this indicates the I2C bus number for DDR SPD.
1371 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1375 If defined, then this indicates the I2C bus number for the RTC.
1376 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1380 If defined, then this indicates the I2C bus number for the DTT.
1381 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1385 Define this option if you want to use Freescale's I2C driver in
1389 - SPI Support: CONFIG_SPI
1391 Enables SPI driver (so far only tested with
1392 SPI EEPROM, also an instance works with Crystal A/D and
1393 D/As on the SACSng board)
1397 Enables extended (16-bit) SPI EEPROM addressing.
1398 (symmetrical to CONFIG_I2C_X)
1402 Enables a software (bit-bang) SPI driver rather than
1403 using hardware support. This is a general purpose
1404 driver that only requires three general I/O port pins
1405 (two outputs, one input) to function. If this is
1406 defined, the board configuration must define several
1407 SPI configuration items (port pins to use, etc). For
1408 an example, see include/configs/sacsng.h.
1410 - FPGA Support: CONFIG_FPGA_COUNT
1412 Specify the number of FPGA devices to support.
1416 Used to specify the types of FPGA devices. For example,
1417 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1419 CFG_FPGA_PROG_FEEDBACK
1421 Enable printing of hash marks during FPGA configuration.
1425 Enable checks on FPGA configuration interface busy
1426 status by the configuration function. This option
1427 will require a board or device specific function to
1432 If defined, a function that provides delays in the FPGA
1433 configuration driver.
1435 CFG_FPGA_CHECK_CTRLC
1436 Allow Control-C to interrupt FPGA configuration
1438 CFG_FPGA_CHECK_ERROR
1440 Check for configuration errors during FPGA bitfile
1441 loading. For example, abort during Virtex II
1442 configuration if the INIT_B line goes low (which
1443 indicated a CRC error).
1447 Maximum time to wait for the INIT_B line to deassert
1448 after PROB_B has been deasserted during a Virtex II
1449 FPGA configuration sequence. The default time is 500
1454 Maximum time to wait for BUSY to deassert during
1455 Virtex II FPGA configuration. The default is 5 mS.
1457 CFG_FPGA_WAIT_CONFIG
1459 Time to wait after FPGA configuration. The default is
1462 - Configuration Management:
1465 If defined, this string will be added to the U-Boot
1466 version information (U_BOOT_VERSION)
1468 - Vendor Parameter Protection:
1470 U-Boot considers the values of the environment
1471 variables "serial#" (Board Serial Number) and
1472 "ethaddr" (Ethernet Address) to be parameters that
1473 are set once by the board vendor / manufacturer, and
1474 protects these variables from casual modification by
1475 the user. Once set, these variables are read-only,
1476 and write or delete attempts are rejected. You can
1477 change this behviour:
1479 If CONFIG_ENV_OVERWRITE is #defined in your config
1480 file, the write protection for vendor parameters is
1481 completely disabled. Anybody can change or delete
1484 Alternatively, if you #define _both_ CONFIG_ETHADDR
1485 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1486 ethernet address is installed in the environment,
1487 which can be changed exactly ONCE by the user. [The
1488 serial# is unaffected by this, i. e. it remains
1494 Define this variable to enable the reservation of
1495 "protected RAM", i. e. RAM which is not overwritten
1496 by U-Boot. Define CONFIG_PRAM to hold the number of
1497 kB you want to reserve for pRAM. You can overwrite
1498 this default value by defining an environment
1499 variable "pram" to the number of kB you want to
1500 reserve. Note that the board info structure will
1501 still show the full amount of RAM. If pRAM is
1502 reserved, a new environment variable "mem" will
1503 automatically be defined to hold the amount of
1504 remaining RAM in a form that can be passed as boot
1505 argument to Linux, for instance like that:
1507 setenv bootargs ... mem=\${mem}
1510 This way you can tell Linux not to use this memory,
1511 either, which results in a memory region that will
1512 not be affected by reboots.
1514 *WARNING* If your board configuration uses automatic
1515 detection of the RAM size, you must make sure that
1516 this memory test is non-destructive. So far, the
1517 following board configurations are known to be
1520 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1521 HERMES, IP860, RPXlite, LWMON, LANTEC,
1522 PCU_E, FLAGADM, TQM8260
1527 Define this variable to stop the system in case of a
1528 fatal error, so that you have to reset it manually.
1529 This is probably NOT a good idea for an embedded
1530 system where you want to system to reboot
1531 automatically as fast as possible, but it may be
1532 useful during development since you can try to debug
1533 the conditions that lead to the situation.
1535 CONFIG_NET_RETRY_COUNT
1537 This variable defines the number of retries for
1538 network operations like ARP, RARP, TFTP, or BOOTP
1539 before giving up the operation. If not defined, a
1540 default value of 5 is used.
1542 - Command Interpreter:
1543 CONFIG_AUTO_COMPLETE
1545 Enable auto completion of commands using TAB.
1547 Note that this feature has NOT been implemented yet
1548 for the "hush" shell.
1553 Define this variable to enable the "hush" shell (from
1554 Busybox) as command line interpreter, thus enabling
1555 powerful command line syntax like
1556 if...then...else...fi conditionals or `&&' and '||'
1557 constructs ("shell scripts").
1559 If undefined, you get the old, much simpler behaviour
1560 with a somewhat smaller memory footprint.
1565 This defines the secondary prompt string, which is
1566 printed when the command interpreter needs more input
1567 to complete a command. Usually "> ".
1571 In the current implementation, the local variables
1572 space and global environment variables space are
1573 separated. Local variables are those you define by
1574 simply typing `name=value'. To access a local
1575 variable later on, you have write `$name' or
1576 `${name}'; to execute the contents of a variable
1577 directly type `$name' at the command prompt.
1579 Global environment variables are those you use
1580 setenv/printenv to work with. To run a command stored
1581 in such a variable, you need to use the run command,
1582 and you must not use the '$' sign to access them.
1584 To store commands and special characters in a
1585 variable, please use double quotation marks
1586 surrounding the whole text of the variable, instead
1587 of the backslashes before semicolons and special
1590 - Commandline Editing and History:
1591 CONFIG_CMDLINE_EDITING
1593 Enable editiong and History functions for interactive
1594 commandline input operations
1596 - Default Environment:
1597 CONFIG_EXTRA_ENV_SETTINGS
1599 Define this to contain any number of null terminated
1600 strings (variable = value pairs) that will be part of
1601 the default environment compiled into the boot image.
1603 For example, place something like this in your
1604 board's config file:
1606 #define CONFIG_EXTRA_ENV_SETTINGS \
1610 Warning: This method is based on knowledge about the
1611 internal format how the environment is stored by the
1612 U-Boot code. This is NOT an official, exported
1613 interface! Although it is unlikely that this format
1614 will change soon, there is no guarantee either.
1615 You better know what you are doing here.
1617 Note: overly (ab)use of the default environment is
1618 discouraged. Make sure to check other ways to preset
1619 the environment like the autoscript function or the
1622 - DataFlash Support:
1623 CONFIG_HAS_DATAFLASH
1625 Defining this option enables DataFlash features and
1626 allows to read/write in Dataflash via the standard
1629 - SystemACE Support:
1632 Adding this option adds support for Xilinx SystemACE
1633 chips attached via some sort of local bus. The address
1634 of the chip must alsh be defined in the
1635 CFG_SYSTEMACE_BASE macro. For example:
1637 #define CONFIG_SYSTEMACE
1638 #define CFG_SYSTEMACE_BASE 0xf0000000
1640 When SystemACE support is added, the "ace" device type
1641 becomes available to the fat commands, i.e. fatls.
1643 - TFTP Fixed UDP Port:
1646 If this is defined, the environment variable tftpsrcp
1647 is used to supply the TFTP UDP source port value.
1648 If tftpsrcp isn't defined, the normal pseudo-random port
1649 number generator is used.
1651 Also, the environment variable tftpdstp is used to supply
1652 the TFTP UDP destination port value. If tftpdstp isn't
1653 defined, the normal port 69 is used.
1655 The purpose for tftpsrcp is to allow a TFTP server to
1656 blindly start the TFTP transfer using the pre-configured
1657 target IP address and UDP port. This has the effect of
1658 "punching through" the (Windows XP) firewall, allowing
1659 the remainder of the TFTP transfer to proceed normally.
1660 A better solution is to properly configure the firewall,
1661 but sometimes that is not allowed.
1663 - Show boot progress:
1664 CONFIG_SHOW_BOOT_PROGRESS
1666 Defining this option allows to add some board-
1667 specific code (calling a user-provided function
1668 "show_boot_progress(int)") that enables you to show
1669 the system's boot progress on some display (for
1670 example, some LED's) on your board. At the moment,
1671 the following checkpoints are implemented:
1674 1 common/cmd_bootm.c before attempting to boot an image
1675 -1 common/cmd_bootm.c Image header has bad magic number
1676 2 common/cmd_bootm.c Image header has correct magic number
1677 -2 common/cmd_bootm.c Image header has bad checksum
1678 3 common/cmd_bootm.c Image header has correct checksum
1679 -3 common/cmd_bootm.c Image data has bad checksum
1680 4 common/cmd_bootm.c Image data has correct checksum
1681 -4 common/cmd_bootm.c Image is for unsupported architecture
1682 5 common/cmd_bootm.c Architecture check OK
1683 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1684 6 common/cmd_bootm.c Image Type check OK
1685 -6 common/cmd_bootm.c gunzip uncompression error
1686 -7 common/cmd_bootm.c Unimplemented compression type
1687 7 common/cmd_bootm.c Uncompression OK
1688 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1689 8 common/cmd_bootm.c Image Type check OK
1690 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1691 9 common/cmd_bootm.c Start initial ramdisk verification
1692 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1693 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1694 10 common/cmd_bootm.c Ramdisk header is OK
1695 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1696 11 common/cmd_bootm.c Ramdisk data has correct checksum
1697 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1698 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1699 13 common/cmd_bootm.c Start multifile image verification
1700 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1701 15 common/cmd_bootm.c All preparation done, transferring control to OS
1703 -30 lib_ppc/board.c Fatal error, hang the system
1704 -31 post/post.c POST test failed, detected by post_output_backlog()
1705 -32 post/post.c POST test failed, detected by post_run_single()
1707 34 common/cmd_doc.c before loading a Image from a DOC device
1708 -35 common/cmd_doc.c Bad usage of "doc" command
1709 35 common/cmd_doc.c correct usage of "doc" command
1710 -36 common/cmd_doc.c No boot device
1711 36 common/cmd_doc.c correct boot device
1712 -37 common/cmd_doc.c Unknown Chip ID on boot device
1713 37 common/cmd_doc.c correct chip ID found, device available
1714 -38 common/cmd_doc.c Read Error on boot device
1715 38 common/cmd_doc.c reading Image header from DOC device OK
1716 -39 common/cmd_doc.c Image header has bad magic number
1717 39 common/cmd_doc.c Image header has correct magic number
1718 -40 common/cmd_doc.c Error reading Image from DOC device
1719 40 common/cmd_doc.c Image header has correct magic number
1720 41 common/cmd_ide.c before loading a Image from a IDE device
1721 -42 common/cmd_ide.c Bad usage of "ide" command
1722 42 common/cmd_ide.c correct usage of "ide" command
1723 -43 common/cmd_ide.c No boot device
1724 43 common/cmd_ide.c boot device found
1725 -44 common/cmd_ide.c Device not available
1726 44 common/cmd_ide.c Device available
1727 -45 common/cmd_ide.c wrong partition selected
1728 45 common/cmd_ide.c partition selected
1729 -46 common/cmd_ide.c Unknown partition table
1730 46 common/cmd_ide.c valid partition table found
1731 -47 common/cmd_ide.c Invalid partition type
1732 47 common/cmd_ide.c correct partition type
1733 -48 common/cmd_ide.c Error reading Image Header on boot device
1734 48 common/cmd_ide.c reading Image Header from IDE device OK
1735 -49 common/cmd_ide.c Image header has bad magic number
1736 49 common/cmd_ide.c Image header has correct magic number
1737 -50 common/cmd_ide.c Image header has bad checksum
1738 50 common/cmd_ide.c Image header has correct checksum
1739 -51 common/cmd_ide.c Error reading Image from IDE device
1740 51 common/cmd_ide.c reading Image from IDE device OK
1741 52 common/cmd_nand.c before loading a Image from a NAND device
1742 -53 common/cmd_nand.c Bad usage of "nand" command
1743 53 common/cmd_nand.c correct usage of "nand" command
1744 -54 common/cmd_nand.c No boot device
1745 54 common/cmd_nand.c boot device found
1746 -55 common/cmd_nand.c Unknown Chip ID on boot device
1747 55 common/cmd_nand.c correct chip ID found, device available
1748 -56 common/cmd_nand.c Error reading Image Header on boot device
1749 56 common/cmd_nand.c reading Image Header from NAND device OK
1750 -57 common/cmd_nand.c Image header has bad magic number
1751 57 common/cmd_nand.c Image header has correct magic number
1752 -58 common/cmd_nand.c Error reading Image from NAND device
1753 58 common/cmd_nand.c reading Image from NAND device OK
1755 -60 common/env_common.c Environment has a bad CRC, using default
1757 64 net/eth.c starting with Ethernetconfiguration.
1758 -64 net/eth.c no Ethernet found.
1759 65 net/eth.c Ethernet found.
1761 -80 common/cmd_net.c usage wrong
1762 80 common/cmd_net.c before calling NetLoop()
1763 -81 common/cmd_net.c some error in NetLoop() occured
1764 81 common/cmd_net.c NetLoop() back without error
1765 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1766 82 common/cmd_net.c trying automatic boot
1767 83 common/cmd_net.c running autoscript
1768 -83 common/cmd_net.c some error in automatic boot or autoscript
1769 84 common/cmd_net.c end without errors
1774 [so far only for SMDK2400 and TRAB boards]
1776 - Modem support endable:
1777 CONFIG_MODEM_SUPPORT
1779 - RTS/CTS Flow control enable:
1782 - Modem debug support:
1783 CONFIG_MODEM_SUPPORT_DEBUG
1785 Enables debugging stuff (char screen[1024], dbg())
1786 for modem support. Useful only with BDI2000.
1788 - Interrupt support (PPC):
1790 There are common interrupt_init() and timer_interrupt()
1791 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1792 for cpu specific initialization. interrupt_init_cpu()
1793 should set decrementer_count to appropriate value. If
1794 cpu resets decrementer automatically after interrupt
1795 (ppc4xx) it should set decrementer_count to zero.
1796 timer_interrupt() calls timer_interrupt_cpu() for cpu
1797 specific handling. If board has watchdog / status_led
1798 / other_activity_monitor it works automatically from
1799 general timer_interrupt().
1803 In the target system modem support is enabled when a
1804 specific key (key combination) is pressed during
1805 power-on. Otherwise U-Boot will boot normally
1806 (autoboot). The key_pressed() fuction is called from
1807 board_init(). Currently key_pressed() is a dummy
1808 function, returning 1 and thus enabling modem
1811 If there are no modem init strings in the
1812 environment, U-Boot proceed to autoboot; the
1813 previous output (banner, info printfs) will be
1816 See also: doc/README.Modem
1819 Configuration Settings:
1820 -----------------------
1822 - CFG_LONGHELP: Defined when you want long help messages included;
1823 undefine this when you're short of memory.
1825 - CFG_PROMPT: This is what U-Boot prints on the console to
1826 prompt for user input.
1828 - CFG_CBSIZE: Buffer size for input from the Console
1830 - CFG_PBSIZE: Buffer size for Console output
1832 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1834 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1835 the application (usually a Linux kernel) when it is
1838 - CFG_BAUDRATE_TABLE:
1839 List of legal baudrate settings for this board.
1841 - CFG_CONSOLE_INFO_QUIET
1842 Suppress display of console information at boot.
1844 - CFG_CONSOLE_IS_IN_ENV
1845 If the board specific function
1846 extern int overwrite_console (void);
1847 returns 1, the stdin, stderr and stdout are switched to the
1848 serial port, else the settings in the environment are used.
1850 - CFG_CONSOLE_OVERWRITE_ROUTINE
1851 Enable the call to overwrite_console().
1853 - CFG_CONSOLE_ENV_OVERWRITE
1854 Enable overwrite of previous console environment settings.
1856 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1857 Begin and End addresses of the area used by the
1861 Enable an alternate, more extensive memory test.
1863 - CFG_MEMTEST_SCRATCH:
1864 Scratch address used by the alternate memory test
1865 You only need to set this if address zero isn't writeable
1867 - CFG_TFTP_LOADADDR:
1868 Default load address for network file downloads
1870 - CFG_LOADS_BAUD_CHANGE:
1871 Enable temporary baudrate change while serial download
1874 Physical start address of SDRAM. _Must_ be 0 here.
1877 Physical start address of Motherboard I/O (if using a
1881 Physical start address of Flash memory.
1884 Physical start address of boot monitor code (set by
1885 make config files to be same as the text base address
1886 (TEXT_BASE) used when linking) - same as
1887 CFG_FLASH_BASE when booting from flash.
1890 Size of memory reserved for monitor code, used to
1891 determine _at_compile_time_ (!) if the environment is
1892 embedded within the U-Boot image, or in a separate
1896 Size of DRAM reserved for malloc() use.
1899 Normally compressed uImages are limited to an
1900 uncompressed size of 8 MBytes. If this is not enough,
1901 you can define CFG_BOOTM_LEN in your board config file
1902 to adjust this setting to your needs.
1905 Maximum size of memory mapped by the startup code of
1906 the Linux kernel; all data that must be processed by
1907 the Linux kernel (bd_info, boot arguments, eventually
1908 initrd image) must be put below this limit.
1910 - CFG_MAX_FLASH_BANKS:
1911 Max number of Flash memory banks
1913 - CFG_MAX_FLASH_SECT:
1914 Max number of sectors on a Flash chip
1916 - CFG_FLASH_ERASE_TOUT:
1917 Timeout for Flash erase operations (in ms)
1919 - CFG_FLASH_WRITE_TOUT:
1920 Timeout for Flash write operations (in ms)
1922 - CFG_FLASH_LOCK_TOUT
1923 Timeout for Flash set sector lock bit operation (in ms)
1925 - CFG_FLASH_UNLOCK_TOUT
1926 Timeout for Flash clear lock bits operation (in ms)
1928 - CFG_FLASH_PROTECTION
1929 If defined, hardware flash sectors protection is used
1930 instead of U-Boot software protection.
1932 - CFG_DIRECT_FLASH_TFTP:
1934 Enable TFTP transfers directly to flash memory;
1935 without this option such a download has to be
1936 performed in two steps: (1) download to RAM, and (2)
1937 copy from RAM to flash.
1939 The two-step approach is usually more reliable, since
1940 you can check if the download worked before you erase
1941 the flash, but in some situations (when sytem RAM is
1942 too limited to allow for a tempory copy of the
1943 downloaded image) this option may be very useful.
1946 Define if the flash driver uses extra elements in the
1947 common flash structure for storing flash geometry.
1949 - CFG_FLASH_CFI_DRIVER
1950 This option also enables the building of the cfi_flash driver
1951 in the drivers directory
1953 - CFG_FLASH_QUIET_TEST
1954 If this option is defined, the common CFI flash doesn't
1955 print it's warning upon not recognized FLASH banks. This
1956 is useful, if some of the configured banks are only
1957 optionally available.
1959 - CFG_RX_ETH_BUFFER:
1960 Defines the number of ethernet receive buffers. On some
1961 ethernet controllers it is recommended to set this value
1962 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1963 buffers can be full shortly after enabling the interface
1964 on high ethernet traffic.
1965 Defaults to 4 if not defined.
1967 The following definitions that deal with the placement and management
1968 of environment data (variable area); in general, we support the
1969 following configurations:
1971 - CFG_ENV_IS_IN_FLASH:
1973 Define this if the environment is in flash memory.
1975 a) The environment occupies one whole flash sector, which is
1976 "embedded" in the text segment with the U-Boot code. This
1977 happens usually with "bottom boot sector" or "top boot
1978 sector" type flash chips, which have several smaller
1979 sectors at the start or the end. For instance, such a
1980 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1981 such a case you would place the environment in one of the
1982 4 kB sectors - with U-Boot code before and after it. With
1983 "top boot sector" type flash chips, you would put the
1984 environment in one of the last sectors, leaving a gap
1985 between U-Boot and the environment.
1989 Offset of environment data (variable area) to the
1990 beginning of flash memory; for instance, with bottom boot
1991 type flash chips the second sector can be used: the offset
1992 for this sector is given here.
1994 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1998 This is just another way to specify the start address of
1999 the flash sector containing the environment (instead of
2002 - CFG_ENV_SECT_SIZE:
2004 Size of the sector containing the environment.
2007 b) Sometimes flash chips have few, equal sized, BIG sectors.
2008 In such a case you don't want to spend a whole sector for
2013 If you use this in combination with CFG_ENV_IS_IN_FLASH
2014 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2015 of this flash sector for the environment. This saves
2016 memory for the RAM copy of the environment.
2018 It may also save flash memory if you decide to use this
2019 when your environment is "embedded" within U-Boot code,
2020 since then the remainder of the flash sector could be used
2021 for U-Boot code. It should be pointed out that this is
2022 STRONGLY DISCOURAGED from a robustness point of view:
2023 updating the environment in flash makes it always
2024 necessary to erase the WHOLE sector. If something goes
2025 wrong before the contents has been restored from a copy in
2026 RAM, your target system will be dead.
2028 - CFG_ENV_ADDR_REDUND
2031 These settings describe a second storage area used to hold
2032 a redundand copy of the environment data, so that there is
2033 a valid backup copy in case there is a power failure during
2034 a "saveenv" operation.
2036 BE CAREFUL! Any changes to the flash layout, and some changes to the
2037 source code will make it necessary to adapt <board>/u-boot.lds*
2041 - CFG_ENV_IS_IN_NVRAM:
2043 Define this if you have some non-volatile memory device
2044 (NVRAM, battery buffered SRAM) which you want to use for the
2050 These two #defines are used to determin the memory area you
2051 want to use for environment. It is assumed that this memory
2052 can just be read and written to, without any special
2055 BE CAREFUL! The first access to the environment happens quite early
2056 in U-Boot initalization (when we try to get the setting of for the
2057 console baudrate). You *MUST* have mappend your NVRAM area then, or
2060 Please note that even with NVRAM we still use a copy of the
2061 environment in RAM: we could work on NVRAM directly, but we want to
2062 keep settings there always unmodified except somebody uses "saveenv"
2063 to save the current settings.
2066 - CFG_ENV_IS_IN_EEPROM:
2068 Use this if you have an EEPROM or similar serial access
2069 device and a driver for it.
2074 These two #defines specify the offset and size of the
2075 environment area within the total memory of your EEPROM.
2077 - CFG_I2C_EEPROM_ADDR:
2078 If defined, specified the chip address of the EEPROM device.
2079 The default address is zero.
2081 - CFG_EEPROM_PAGE_WRITE_BITS:
2082 If defined, the number of bits used to address bytes in a
2083 single page in the EEPROM device. A 64 byte page, for example
2084 would require six bits.
2086 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2087 If defined, the number of milliseconds to delay between
2088 page writes. The default is zero milliseconds.
2090 - CFG_I2C_EEPROM_ADDR_LEN:
2091 The length in bytes of the EEPROM memory array address. Note
2092 that this is NOT the chip address length!
2094 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2095 EEPROM chips that implement "address overflow" are ones
2096 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2097 address and the extra bits end up in the "chip address" bit
2098 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2101 Note that we consider the length of the address field to
2102 still be one byte because the extra address bits are hidden
2103 in the chip address.
2106 The size in bytes of the EEPROM device.
2109 - CFG_ENV_IS_IN_DATAFLASH:
2111 Define this if you have a DataFlash memory device which you
2112 want to use for the environment.
2118 These three #defines specify the offset and size of the
2119 environment area within the total memory of your DataFlash placed
2120 at the specified address.
2122 - CFG_ENV_IS_IN_NAND:
2124 Define this if you have a NAND device which you want to use
2125 for the environment.
2130 These two #defines specify the offset and size of the environment
2131 area within the first NAND device.
2133 - CFG_ENV_OFFSET_REDUND
2135 This setting describes a second storage area of CFG_ENV_SIZE
2136 size used to hold a redundant copy of the environment data,
2137 so that there is a valid backup copy in case there is a
2138 power failure during a "saveenv" operation.
2140 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2141 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2142 the NAND devices block size.
2144 - CFG_SPI_INIT_OFFSET
2146 Defines offset to the initial SPI buffer area in DPRAM. The
2147 area is used at an early stage (ROM part) if the environment
2148 is configured to reside in the SPI EEPROM: We need a 520 byte
2149 scratch DPRAM area. It is used between the two initialization
2150 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2151 to be a good choice since it makes it far enough from the
2152 start of the data area as well as from the stack pointer.
2154 Please note that the environment is read-only as long as the monitor
2155 has been relocated to RAM and a RAM copy of the environment has been
2156 created; also, when using EEPROM you will have to use getenv_r()
2157 until then to read environment variables.
2159 The environment is protected by a CRC32 checksum. Before the monitor
2160 is relocated into RAM, as a result of a bad CRC you will be working
2161 with the compiled-in default environment - *silently*!!! [This is
2162 necessary, because the first environment variable we need is the
2163 "baudrate" setting for the console - if we have a bad CRC, we don't
2164 have any device yet where we could complain.]
2166 Note: once the monitor has been relocated, then it will complain if
2167 the default environment is used; a new CRC is computed as soon as you
2168 use the "saveenv" command to store a valid environment.
2170 - CFG_FAULT_ECHO_LINK_DOWN:
2171 Echo the inverted Ethernet link state to the fault LED.
2173 Note: If this option is active, then CFG_FAULT_MII_ADDR
2174 also needs to be defined.
2176 - CFG_FAULT_MII_ADDR:
2177 MII address of the PHY to check for the Ethernet link state.
2179 - CFG_64BIT_VSPRINTF:
2180 Makes vsprintf (and all *printf functions) support printing
2181 of 64bit values by using the L quantifier
2183 - CFG_64BIT_STRTOUL:
2184 Adds simple_strtoull that returns a 64bit value
2186 Low Level (hardware related) configuration options:
2187 ---------------------------------------------------
2189 - CFG_CACHELINE_SIZE:
2190 Cache Line Size of the CPU.
2193 Default address of the IMMR after system reset.
2195 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2196 and RPXsuper) to be able to adjust the position of
2197 the IMMR register after a reset.
2199 - Floppy Disk Support:
2200 CFG_FDC_DRIVE_NUMBER
2202 the default drive number (default value 0)
2206 defines the spacing between fdc chipset registers
2211 defines the offset of register from address. It
2212 depends on which part of the data bus is connected to
2213 the fdc chipset. (default value 0)
2215 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2216 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2219 if CFG_FDC_HW_INIT is defined, then the function
2220 fdc_hw_init() is called at the beginning of the FDC
2221 setup. fdc_hw_init() must be provided by the board
2222 source code. It is used to make hardware dependant
2225 - CFG_IMMR: Physical address of the Internal Memory.
2226 DO NOT CHANGE unless you know exactly what you're
2227 doing! (11-4) [MPC8xx/82xx systems only]
2229 - CFG_INIT_RAM_ADDR:
2231 Start address of memory area that can be used for
2232 initial data and stack; please note that this must be
2233 writable memory that is working WITHOUT special
2234 initialization, i. e. you CANNOT use normal RAM which
2235 will become available only after programming the
2236 memory controller and running certain initialization
2239 U-Boot uses the following memory types:
2240 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2241 - MPC824X: data cache
2242 - PPC4xx: data cache
2244 - CFG_GBL_DATA_OFFSET:
2246 Offset of the initial data structure in the memory
2247 area defined by CFG_INIT_RAM_ADDR. Usually
2248 CFG_GBL_DATA_OFFSET is chosen such that the initial
2249 data is located at the end of the available space
2250 (sometimes written as (CFG_INIT_RAM_END -
2251 CFG_INIT_DATA_SIZE), and the initial stack is just
2252 below that area (growing from (CFG_INIT_RAM_ADDR +
2253 CFG_GBL_DATA_OFFSET) downward.
2256 On the MPC824X (or other systems that use the data
2257 cache for initial memory) the address chosen for
2258 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2259 point to an otherwise UNUSED address space between
2260 the top of RAM and the start of the PCI space.
2262 - CFG_SIUMCR: SIU Module Configuration (11-6)
2264 - CFG_SYPCR: System Protection Control (11-9)
2266 - CFG_TBSCR: Time Base Status and Control (11-26)
2268 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2270 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2272 - CFG_SCCR: System Clock and reset Control Register (15-27)
2274 - CFG_OR_TIMING_SDRAM:
2278 periodic timer for refresh
2280 - CFG_DER: Debug Event Register (37-47)
2282 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2283 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2284 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2286 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2288 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2289 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2290 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2291 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2293 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2294 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2295 Machine Mode Register and Memory Periodic Timer
2296 Prescaler definitions (SDRAM timing)
2298 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2299 enable I2C microcode relocation patch (MPC8xx);
2300 define relocation offset in DPRAM [DSP2]
2302 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2303 enable SPI microcode relocation patch (MPC8xx);
2304 define relocation offset in DPRAM [SCC4]
2307 Use OSCM clock mode on MBX8xx board. Be careful,
2308 wrong setting might damage your board. Read
2309 doc/README.MBX before setting this variable!
2311 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2312 Offset of the bootmode word in DPRAM used by post
2313 (Power On Self Tests). This definition overrides
2314 #define'd default value in commproc.h resp.
2317 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2318 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2319 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2320 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2321 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2322 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2323 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2324 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2325 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2328 Get DDR timing information from an I2C EEPROM. Common with pluggable
2329 memory modules such as SODIMMs
2331 I2C address of the SPD EEPROM
2334 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2335 Note that the value must resolve to something your driver can deal with.
2337 - CFG_83XX_DDR_USES_CS0
2338 Only for 83xx systems. If specified, then DDR should be configured
2339 using CS0 and CS1 instead of CS2 and CS3.
2341 - CFG_83XX_DDR_USES_CS0
2342 Only for 83xx systems. If specified, then DDR should be configured
2343 using CS0 and CS1 instead of CS2 and CS3.
2345 - CONFIG_ETHER_ON_FEC[12]
2346 Define to enable FEC[12] on a 8xx series processor.
2348 - CONFIG_FEC[12]_PHY
2349 Define to the hardcoded PHY address which corresponds
2350 to the given FEC; i. e.
2351 #define CONFIG_FEC1_PHY 4
2352 means that the PHY with address 4 is connected to FEC1
2354 When set to -1, means to probe for first available.
2356 - CONFIG_FEC[12]_PHY_NORXERR
2357 The PHY does not have a RXERR line (RMII only).
2358 (so program the FEC to ignore it).
2361 Enable RMII mode for all FECs.
2362 Note that this is a global option, we can't
2363 have one FEC in standard MII mode and another in RMII mode.
2365 - CONFIG_CRC32_VERIFY
2366 Add a verify option to the crc32 command.
2369 => crc32 -v <address> <count> <crc32>
2371 Where address/count indicate a memory area
2372 and crc32 is the correct crc32 which the
2376 Add the "loopw" memory command. This only takes effect if
2377 the memory commands are activated globally (CFG_CMD_MEM).
2380 Add the "mdc" and "mwc" memory commands. These are cyclic
2385 This command will print 4 bytes (10,11,12,13) each 500 ms.
2387 => mwc.l 100 12345678 10
2388 This command will write 12345678 to address 100 all 10 ms.
2390 This only takes effect if the memory commands are activated
2391 globally (CFG_CMD_MEM).
2393 - CONFIG_SKIP_LOWLEVEL_INIT
2394 - CONFIG_SKIP_RELOCATE_UBOOT
2396 [ARM only] If these variables are defined, then
2397 certain low level initializations (like setting up
2398 the memory controller) are omitted and/or U-Boot does
2399 not relocate itself into RAM.
2400 Normally these variables MUST NOT be defined. The
2401 only exception is when U-Boot is loaded (to RAM) by
2402 some other boot loader or by a debugger which
2403 performs these intializations itself.
2406 Building the Software:
2407 ======================
2409 Building U-Boot has been tested in native PPC environments (on a
2410 PowerBook G3 running LinuxPPC 2000) and in cross environments
2411 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2414 If you are not using a native PPC environment, it is assumed that you
2415 have the GNU cross compiling tools available in your path and named
2416 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2417 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2418 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2421 CROSS_COMPILE = ppc_4xx-
2424 U-Boot is intended to be simple to build. After installing the
2425 sources you must configure U-Boot for one specific board type. This
2430 where "NAME_config" is the name of one of the existing
2431 configurations; the following names are supported:
2433 ADCIOP_config FPS860L_config omap730p2_config
2434 ADS860_config GEN860T_config pcu_e_config
2436 AR405_config GENIETV_config PIP405_config
2437 at91rm9200dk_config GTH_config QS823_config
2438 CANBT_config hermes_config QS850_config
2439 cmi_mpc5xx_config hymod_config QS860T_config
2440 cogent_common_config IP860_config RPXlite_config
2441 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2442 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2443 CPCI405_config JSE_config rsdproto_config
2444 CPCIISER4_config LANTEC_config Sandpoint8240_config
2445 csb272_config lwmon_config sbc8260_config
2446 CU824_config MBX860T_config sbc8560_33_config
2447 DUET_ADS_config MBX_config sbc8560_66_config
2448 EBONY_config mpc7448hpc2_config SM850_config
2449 ELPT860_config MPC8260ADS_config SPD823TS_config
2450 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2451 ETX094_config MPC8540EVAL_config SXNI855T_config
2452 FADS823_config NMPC8560ADS_config TQM823L_config
2453 FADS850SAR_config NETVIA_config TQM850L_config
2454 FADS860T_config omap1510inn_config TQM855L_config
2455 FPS850L_config omap1610h2_config TQM860L_config
2456 omap1610inn_config walnut_config
2457 omap5912osk_config Yukon8220_config
2458 omap2420h4_config ZPC1900_config
2460 Note: for some board special configuration names may exist; check if
2461 additional information is available from the board vendor; for
2462 instance, the TQM823L systems are available without (standard)
2463 or with LCD support. You can select such additional "features"
2464 when chosing the configuration, i. e.
2467 - will configure for a plain TQM823L, i. e. no LCD support
2469 make TQM823L_LCD_config
2470 - will configure for a TQM823L with U-Boot console on LCD
2475 Finally, type "make all", and you should get some working U-Boot
2476 images ready for download to / installation on your system:
2478 - "u-boot.bin" is a raw binary image
2479 - "u-boot" is an image in ELF binary format
2480 - "u-boot.srec" is in Motorola S-Record format
2482 By default the build is performed locally and the objects are saved
2483 in the source directory. One of the two methods can be used to change
2484 this behavior and build U-Boot to some external directory:
2486 1. Add O= to the make command line invocations:
2488 make O=/tmp/build distclean
2489 make O=/tmp/build NAME_config
2490 make O=/tmp/build all
2492 2. Set environment variable BUILD_DIR to point to the desired location:
2494 export BUILD_DIR=/tmp/build
2499 Note that the command line "O=" setting overrides the BUILD_DIR environment
2503 Please be aware that the Makefiles assume you are using GNU make, so
2504 for instance on NetBSD you might need to use "gmake" instead of
2508 If the system board that you have is not listed, then you will need
2509 to port U-Boot to your hardware platform. To do this, follow these
2512 1. Add a new configuration option for your board to the toplevel
2513 "Makefile" and to the "MAKEALL" script, using the existing
2514 entries as examples. Note that here and at many other places
2515 boards and other names are listed in alphabetical sort order. Please
2517 2. Create a new directory to hold your board specific code. Add any
2518 files you need. In your board directory, you will need at least
2519 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2520 3. Create a new configuration file "include/configs/<board>.h" for
2522 3. If you're porting U-Boot to a new CPU, then also create a new
2523 directory to hold your CPU specific code. Add any files you need.
2524 4. Run "make <board>_config" with your new name.
2525 5. Type "make", and you should get a working "u-boot.srec" file
2526 to be installed on your target system.
2527 6. Debug and solve any problems that might arise.
2528 [Of course, this last step is much harder than it sounds.]
2531 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2532 ==============================================================
2534 If you have modified U-Boot sources (for instance added a new board
2535 or support for new devices, a new CPU, etc.) you are expected to
2536 provide feedback to the other developers. The feedback normally takes
2537 the form of a "patch", i. e. a context diff against a certain (latest
2538 official or latest in CVS) version of U-Boot sources.
2540 But before you submit such a patch, please verify that your modifi-
2541 cation did not break existing code. At least make sure that *ALL* of
2542 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2543 just run the "MAKEALL" script, which will configure and build U-Boot
2544 for ALL supported system. Be warned, this will take a while. You can
2545 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2546 environment variable to the script, i. e. to use the cross tools from
2547 MontaVista's Hard Hat Linux you can type
2549 CROSS_COMPILE=ppc_8xx- MAKEALL
2551 or to build on a native PowerPC system you can type
2553 CROSS_COMPILE=' ' MAKEALL
2555 When using the MAKEALL script, the default behaviour is to build U-Boot
2556 in the source directory. This location can be changed by setting the
2557 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2558 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2559 <source dir>/LOG directory. This default location can be changed by
2560 setting the MAKEALL_LOGDIR environment variable. For example:
2562 export BUILD_DIR=/tmp/build
2563 export MAKEALL_LOGDIR=/tmp/log
2564 CROSS_COMPILE=ppc_8xx- MAKEALL
2566 With the above settings build objects are saved in the /tmp/build, log
2567 files are saved in the /tmp/log and the source tree remains clean during
2568 the whole build process.
2571 See also "U-Boot Porting Guide" below.
2574 Monitor Commands - Overview:
2575 ============================
2577 go - start application at address 'addr'
2578 run - run commands in an environment variable
2579 bootm - boot application image from memory
2580 bootp - boot image via network using BootP/TFTP protocol
2581 tftpboot- boot image via network using TFTP protocol
2582 and env variables "ipaddr" and "serverip"
2583 (and eventually "gatewayip")
2584 rarpboot- boot image via network using RARP/TFTP protocol
2585 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2586 loads - load S-Record file over serial line
2587 loadb - load binary file over serial line (kermit mode)
2589 mm - memory modify (auto-incrementing)
2590 nm - memory modify (constant address)
2591 mw - memory write (fill)
2593 cmp - memory compare
2594 crc32 - checksum calculation
2595 imd - i2c memory display
2596 imm - i2c memory modify (auto-incrementing)
2597 inm - i2c memory modify (constant address)
2598 imw - i2c memory write (fill)
2599 icrc32 - i2c checksum calculation
2600 iprobe - probe to discover valid I2C chip addresses
2601 iloop - infinite loop on address range
2602 isdram - print SDRAM configuration information
2603 sspi - SPI utility commands
2604 base - print or set address offset
2605 printenv- print environment variables
2606 setenv - set environment variables
2607 saveenv - save environment variables to persistent storage
2608 protect - enable or disable FLASH write protection
2609 erase - erase FLASH memory
2610 flinfo - print FLASH memory information
2611 bdinfo - print Board Info structure
2612 iminfo - print header information for application image
2613 coninfo - print console devices and informations
2614 ide - IDE sub-system
2615 loop - infinite loop on address range
2616 loopw - infinite write loop on address range
2617 mtest - simple RAM test
2618 icache - enable or disable instruction cache
2619 dcache - enable or disable data cache
2620 reset - Perform RESET of the CPU
2621 echo - echo args to console
2622 version - print monitor version
2623 help - print online help
2624 ? - alias for 'help'
2627 Monitor Commands - Detailed Description:
2628 ========================================
2632 For now: just type "help <command>".
2635 Environment Variables:
2636 ======================
2638 U-Boot supports user configuration using Environment Variables which
2639 can be made persistent by saving to Flash memory.
2641 Environment Variables are set using "setenv", printed using
2642 "printenv", and saved to Flash using "saveenv". Using "setenv"
2643 without a value can be used to delete a variable from the
2644 environment. As long as you don't save the environment you are
2645 working with an in-memory copy. In case the Flash area containing the
2646 environment is erased by accident, a default environment is provided.
2648 Some configuration options can be set using Environment Variables:
2650 baudrate - see CONFIG_BAUDRATE
2652 bootdelay - see CONFIG_BOOTDELAY
2654 bootcmd - see CONFIG_BOOTCOMMAND
2656 bootargs - Boot arguments when booting an RTOS image
2658 bootfile - Name of the image to load with TFTP
2660 autoload - if set to "no" (any string beginning with 'n'),
2661 "bootp" will just load perform a lookup of the
2662 configuration from the BOOTP server, but not try to
2663 load any image using TFTP
2665 autostart - if set to "yes", an image loaded using the "bootp",
2666 "rarpboot", "tftpboot" or "diskboot" commands will
2667 be automatically started (by internally calling
2670 If set to "no", a standalone image passed to the
2671 "bootm" command will be copied to the load address
2672 (and eventually uncompressed), but NOT be started.
2673 This can be used to load and uncompress arbitrary
2676 i2cfast - (PPC405GP|PPC405EP only)
2677 if set to 'y' configures Linux I2C driver for fast
2678 mode (400kHZ). This environment variable is used in
2679 initialization code. So, for changes to be effective
2680 it must be saved and board must be reset.
2682 initrd_high - restrict positioning of initrd images:
2683 If this variable is not set, initrd images will be
2684 copied to the highest possible address in RAM; this
2685 is usually what you want since it allows for
2686 maximum initrd size. If for some reason you want to
2687 make sure that the initrd image is loaded below the
2688 CFG_BOOTMAPSZ limit, you can set this environment
2689 variable to a value of "no" or "off" or "0".
2690 Alternatively, you can set it to a maximum upper
2691 address to use (U-Boot will still check that it
2692 does not overwrite the U-Boot stack and data).
2694 For instance, when you have a system with 16 MB
2695 RAM, and want to reserve 4 MB from use by Linux,
2696 you can do this by adding "mem=12M" to the value of
2697 the "bootargs" variable. However, now you must make
2698 sure that the initrd image is placed in the first
2699 12 MB as well - this can be done with
2701 setenv initrd_high 00c00000
2703 If you set initrd_high to 0xFFFFFFFF, this is an
2704 indication to U-Boot that all addresses are legal
2705 for the Linux kernel, including addresses in flash
2706 memory. In this case U-Boot will NOT COPY the
2707 ramdisk at all. This may be useful to reduce the
2708 boot time on your system, but requires that this
2709 feature is supported by your Linux kernel.
2711 ipaddr - IP address; needed for tftpboot command
2713 loadaddr - Default load address for commands like "bootp",
2714 "rarpboot", "tftpboot", "loadb" or "diskboot"
2716 loads_echo - see CONFIG_LOADS_ECHO
2718 serverip - TFTP server IP address; needed for tftpboot command
2720 bootretry - see CONFIG_BOOT_RETRY_TIME
2722 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2724 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2726 ethprime - When CONFIG_NET_MULTI is enabled controls which
2727 interface is used first.
2729 ethact - When CONFIG_NET_MULTI is enabled controls which
2730 interface is currently active. For example you
2731 can do the following
2733 => setenv ethact FEC ETHERNET
2734 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2735 => setenv ethact SCC ETHERNET
2736 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2738 netretry - When set to "no" each network operation will
2739 either succeed or fail without retrying.
2740 When set to "once" the network operation will
2741 fail when all the available network interfaces
2742 are tried once without success.
2743 Useful on scripts which control the retry operation
2746 tftpsrcport - If this is set, the value is used for TFTP's
2749 tftpdstport - If this is set, the value is used for TFTP's UDP
2750 destination port instead of the Well Know Port 69.
2752 vlan - When set to a value < 4095 the traffic over
2753 ethernet is encapsulated/received over 802.1q
2756 The following environment variables may be used and automatically
2757 updated by the network boot commands ("bootp" and "rarpboot"),
2758 depending the information provided by your boot server:
2760 bootfile - see above
2761 dnsip - IP address of your Domain Name Server
2762 dnsip2 - IP address of your secondary Domain Name Server
2763 gatewayip - IP address of the Gateway (Router) to use
2764 hostname - Target hostname
2766 netmask - Subnet Mask
2767 rootpath - Pathname of the root filesystem on the NFS server
2768 serverip - see above
2771 There are two special Environment Variables:
2773 serial# - contains hardware identification information such
2774 as type string and/or serial number
2775 ethaddr - Ethernet address
2777 These variables can be set only once (usually during manufacturing of
2778 the board). U-Boot refuses to delete or overwrite these variables
2779 once they have been set once.
2782 Further special Environment Variables:
2784 ver - Contains the U-Boot version string as printed
2785 with the "version" command. This variable is
2786 readonly (see CONFIG_VERSION_VARIABLE).
2789 Please note that changes to some configuration parameters may take
2790 only effect after the next boot (yes, that's just like Windoze :-).
2793 Command Line Parsing:
2794 =====================
2796 There are two different command line parsers available with U-Boot:
2797 the old "simple" one, and the much more powerful "hush" shell:
2799 Old, simple command line parser:
2800 --------------------------------
2802 - supports environment variables (through setenv / saveenv commands)
2803 - several commands on one line, separated by ';'
2804 - variable substitution using "... ${name} ..." syntax
2805 - special characters ('$', ';') can be escaped by prefixing with '\',
2807 setenv bootcmd bootm \${address}
2808 - You can also escape text by enclosing in single apostrophes, for example:
2809 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2814 - similar to Bourne shell, with control structures like
2815 if...then...else...fi, for...do...done; while...do...done,
2816 until...do...done, ...
2817 - supports environment ("global") variables (through setenv / saveenv
2818 commands) and local shell variables (through standard shell syntax
2819 "name=value"); only environment variables can be used with "run"
2825 (1) If a command line (or an environment variable executed by a "run"
2826 command) contains several commands separated by semicolon, and
2827 one of these commands fails, then the remaining commands will be
2830 (2) If you execute several variables with one call to run (i. e.
2831 calling run with a list af variables as arguments), any failing
2832 command will cause "run" to terminate, i. e. the remaining
2833 variables are not executed.
2835 Note for Redundant Ethernet Interfaces:
2836 =======================================
2838 Some boards come with redundant ethernet interfaces; U-Boot supports
2839 such configurations and is capable of automatic selection of a
2840 "working" interface when needed. MAC assignment works as follows:
2842 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2843 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2844 "eth1addr" (=>eth1), "eth2addr", ...
2846 If the network interface stores some valid MAC address (for instance
2847 in SROM), this is used as default address if there is NO correspon-
2848 ding setting in the environment; if the corresponding environment
2849 variable is set, this overrides the settings in the card; that means:
2851 o If the SROM has a valid MAC address, and there is no address in the
2852 environment, the SROM's address is used.
2854 o If there is no valid address in the SROM, and a definition in the
2855 environment exists, then the value from the environment variable is
2858 o If both the SROM and the environment contain a MAC address, and
2859 both addresses are the same, this MAC address is used.
2861 o If both the SROM and the environment contain a MAC address, and the
2862 addresses differ, the value from the environment is used and a
2865 o If neither SROM nor the environment contain a MAC address, an error
2872 The "boot" commands of this monitor operate on "image" files which
2873 can be basicly anything, preceeded by a special header; see the
2874 definitions in include/image.h for details; basicly, the header
2875 defines the following image properties:
2877 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2878 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2879 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2880 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2881 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2882 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2883 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2884 * Compression Type (uncompressed, gzip, bzip2)
2890 The header is marked by a special Magic Number, and both the header
2891 and the data portions of the image are secured against corruption by
2898 Although U-Boot should support any OS or standalone application
2899 easily, the main focus has always been on Linux during the design of
2902 U-Boot includes many features that so far have been part of some
2903 special "boot loader" code within the Linux kernel. Also, any
2904 "initrd" images to be used are no longer part of one big Linux image;
2905 instead, kernel and "initrd" are separate images. This implementation
2906 serves several purposes:
2908 - the same features can be used for other OS or standalone
2909 applications (for instance: using compressed images to reduce the
2910 Flash memory footprint)
2912 - it becomes much easier to port new Linux kernel versions because
2913 lots of low-level, hardware dependent stuff are done by U-Boot
2915 - the same Linux kernel image can now be used with different "initrd"
2916 images; of course this also means that different kernel images can
2917 be run with the same "initrd". This makes testing easier (you don't
2918 have to build a new "zImage.initrd" Linux image when you just
2919 change a file in your "initrd"). Also, a field-upgrade of the
2920 software is easier now.
2926 Porting Linux to U-Boot based systems:
2927 ---------------------------------------
2929 U-Boot cannot save you from doing all the necessary modifications to
2930 configure the Linux device drivers for use with your target hardware
2931 (no, we don't intend to provide a full virtual machine interface to
2934 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2936 Just make sure your machine specific header file (for instance
2937 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2938 Information structure as we define in include/u-boot.h, and make
2939 sure that your definition of IMAP_ADDR uses the same value as your
2940 U-Boot configuration in CFG_IMMR.
2943 Configuring the Linux kernel:
2944 -----------------------------
2946 No specific requirements for U-Boot. Make sure you have some root
2947 device (initial ramdisk, NFS) for your target system.
2950 Building a Linux Image:
2951 -----------------------
2953 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2954 not used. If you use recent kernel source, a new build target
2955 "uImage" will exist which automatically builds an image usable by
2956 U-Boot. Most older kernels also have support for a "pImage" target,
2957 which was introduced for our predecessor project PPCBoot and uses a
2958 100% compatible format.
2967 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2968 encapsulate a compressed Linux kernel image with header information,
2969 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2971 * build a standard "vmlinux" kernel image (in ELF binary format):
2973 * convert the kernel into a raw binary image:
2975 ${CROSS_COMPILE}-objcopy -O binary \
2976 -R .note -R .comment \
2977 -S vmlinux linux.bin
2979 * compress the binary image:
2983 * package compressed binary image for U-Boot:
2985 mkimage -A ppc -O linux -T kernel -C gzip \
2986 -a 0 -e 0 -n "Linux Kernel Image" \
2987 -d linux.bin.gz uImage
2990 The "mkimage" tool can also be used to create ramdisk images for use
2991 with U-Boot, either separated from the Linux kernel image, or
2992 combined into one file. "mkimage" encapsulates the images with a 64
2993 byte header containing information about target architecture,
2994 operating system, image type, compression method, entry points, time
2995 stamp, CRC32 checksums, etc.
2997 "mkimage" can be called in two ways: to verify existing images and
2998 print the header information, or to build new images.
3000 In the first form (with "-l" option) mkimage lists the information
3001 contained in the header of an existing U-Boot image; this includes
3002 checksum verification:
3004 tools/mkimage -l image
3005 -l ==> list image header information
3007 The second form (with "-d" option) is used to build a U-Boot image
3008 from a "data file" which is used as image payload:
3010 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3011 -n name -d data_file image
3012 -A ==> set architecture to 'arch'
3013 -O ==> set operating system to 'os'
3014 -T ==> set image type to 'type'
3015 -C ==> set compression type 'comp'
3016 -a ==> set load address to 'addr' (hex)
3017 -e ==> set entry point to 'ep' (hex)
3018 -n ==> set image name to 'name'
3019 -d ==> use image data from 'datafile'
3021 Right now, all Linux kernels for PowerPC systems use the same load
3022 address (0x00000000), but the entry point address depends on the
3025 - 2.2.x kernels have the entry point at 0x0000000C,
3026 - 2.3.x and later kernels have the entry point at 0x00000000.
3028 So a typical call to build a U-Boot image would read:
3030 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3031 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3032 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3033 > examples/uImage.TQM850L
3034 Image Name: 2.4.4 kernel for TQM850L
3035 Created: Wed Jul 19 02:34:59 2000
3036 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3037 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3038 Load Address: 0x00000000
3039 Entry Point: 0x00000000
3041 To verify the contents of the image (or check for corruption):
3043 -> tools/mkimage -l examples/uImage.TQM850L
3044 Image Name: 2.4.4 kernel for TQM850L
3045 Created: Wed Jul 19 02:34:59 2000
3046 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3047 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3048 Load Address: 0x00000000
3049 Entry Point: 0x00000000
3051 NOTE: for embedded systems where boot time is critical you can trade
3052 speed for memory and install an UNCOMPRESSED image instead: this
3053 needs more space in Flash, but boots much faster since it does not
3054 need to be uncompressed:
3056 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3057 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3058 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3059 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3060 > examples/uImage.TQM850L-uncompressed
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 (uncompressed)
3064 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3065 Load Address: 0x00000000
3066 Entry Point: 0x00000000
3069 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3070 when your kernel is intended to use an initial ramdisk:
3072 -> tools/mkimage -n 'Simple Ramdisk Image' \
3073 > -A ppc -O linux -T ramdisk -C gzip \
3074 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3075 Image Name: Simple Ramdisk Image
3076 Created: Wed Jan 12 14:01:50 2000
3077 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3078 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3079 Load Address: 0x00000000
3080 Entry Point: 0x00000000
3083 Installing a Linux Image:
3084 -------------------------
3086 To downloading a U-Boot image over the serial (console) interface,
3087 you must convert the image to S-Record format:
3089 objcopy -I binary -O srec examples/image examples/image.srec
3091 The 'objcopy' does not understand the information in the U-Boot
3092 image header, so the resulting S-Record file will be relative to
3093 address 0x00000000. To load it to a given address, you need to
3094 specify the target address as 'offset' parameter with the 'loads'
3097 Example: install the image to address 0x40100000 (which on the
3098 TQM8xxL is in the first Flash bank):
3100 => erase 40100000 401FFFFF
3106 ## Ready for S-Record download ...
3107 ~>examples/image.srec
3108 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3110 15989 15990 15991 15992
3111 [file transfer complete]
3113 ## Start Addr = 0x00000000
3116 You can check the success of the download using the 'iminfo' command;
3117 this includes a checksum verification so you can be sure no data
3118 corruption happened:
3122 ## Checking Image at 40100000 ...
3123 Image Name: 2.2.13 for initrd on TQM850L
3124 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3125 Data Size: 335725 Bytes = 327 kB = 0 MB
3126 Load Address: 00000000
3127 Entry Point: 0000000c
3128 Verifying Checksum ... OK
3134 The "bootm" command is used to boot an application that is stored in
3135 memory (RAM or Flash). In case of a Linux kernel image, the contents
3136 of the "bootargs" environment variable is passed to the kernel as
3137 parameters. You can check and modify this variable using the
3138 "printenv" and "setenv" commands:
3141 => printenv bootargs
3142 bootargs=root=/dev/ram
3144 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3146 => printenv bootargs
3147 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3150 ## Booting Linux kernel at 40020000 ...
3151 Image Name: 2.2.13 for NFS on TQM850L
3152 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3153 Data Size: 381681 Bytes = 372 kB = 0 MB
3154 Load Address: 00000000
3155 Entry Point: 0000000c
3156 Verifying Checksum ... OK
3157 Uncompressing Kernel Image ... OK
3158 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
3159 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3160 time_init: decrementer frequency = 187500000/60
3161 Calibrating delay loop... 49.77 BogoMIPS
3162 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3165 If you want to boot a Linux kernel with initial ram disk, you pass
3166 the memory addresses of both the kernel and the initrd image (PPBCOOT
3167 format!) to the "bootm" command:
3169 => imi 40100000 40200000
3171 ## Checking Image at 40100000 ...
3172 Image Name: 2.2.13 for initrd on TQM850L
3173 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3174 Data Size: 335725 Bytes = 327 kB = 0 MB
3175 Load Address: 00000000
3176 Entry Point: 0000000c
3177 Verifying Checksum ... OK
3179 ## Checking Image at 40200000 ...
3180 Image Name: Simple Ramdisk Image
3181 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3182 Data Size: 566530 Bytes = 553 kB = 0 MB
3183 Load Address: 00000000
3184 Entry Point: 00000000
3185 Verifying Checksum ... OK
3187 => bootm 40100000 40200000
3188 ## Booting Linux kernel 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
3195 Uncompressing Kernel Image ... OK
3196 ## Loading RAMDisk 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
3203 Loading Ramdisk ... OK
3204 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
3205 Boot arguments: root=/dev/ram
3206 time_init: decrementer frequency = 187500000/60
3207 Calibrating delay loop... 49.77 BogoMIPS
3209 RAMDISK: Compressed image found at block 0
3210 VFS: Mounted root (ext2 filesystem).
3214 Boot Linux and pass a flat device tree:
3217 First, U-Boot must be compiled with the appropriate defines. See the section
3218 titled "Linux Kernel Interface" above for a more in depth explanation. The
3219 following is an example of how to start a kernel and pass an updated
3225 oft=oftrees/mpc8540ads.dtb
3226 => tftp $oftaddr $oft
3227 Speed: 1000, full duplex
3229 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3230 Filename 'oftrees/mpc8540ads.dtb'.
3231 Load address: 0x300000
3234 Bytes transferred = 4106 (100a hex)
3235 => tftp $loadaddr $bootfile
3236 Speed: 1000, full duplex
3238 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3240 Load address: 0x200000
3241 Loading:############
3243 Bytes transferred = 1029407 (fb51f hex)
3248 => bootm $loadaddr - $oftaddr
3249 ## Booting image at 00200000 ...
3250 Image Name: Linux-2.6.17-dirty
3251 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3252 Data Size: 1029343 Bytes = 1005.2 kB
3253 Load Address: 00000000
3254 Entry Point: 00000000
3255 Verifying Checksum ... OK
3256 Uncompressing Kernel Image ... OK
3257 Booting using flat device tree at 0x300000
3258 Using MPC85xx ADS machine description
3259 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3263 More About U-Boot Image Types:
3264 ------------------------------
3266 U-Boot supports the following image types:
3268 "Standalone Programs" are directly runnable in the environment
3269 provided by U-Boot; it is expected that (if they behave
3270 well) you can continue to work in U-Boot after return from
3271 the Standalone Program.
3272 "OS Kernel Images" are usually images of some Embedded OS which
3273 will take over control completely. Usually these programs
3274 will install their own set of exception handlers, device
3275 drivers, set up the MMU, etc. - this means, that you cannot
3276 expect to re-enter U-Boot except by resetting the CPU.
3277 "RAMDisk Images" are more or less just data blocks, and their
3278 parameters (address, size) are passed to an OS kernel that is
3280 "Multi-File Images" contain several images, typically an OS
3281 (Linux) kernel image and one or more data images like
3282 RAMDisks. This construct is useful for instance when you want
3283 to boot over the network using BOOTP etc., where the boot
3284 server provides just a single image file, but you want to get
3285 for instance an OS kernel and a RAMDisk image.
3287 "Multi-File Images" start with a list of image sizes, each
3288 image size (in bytes) specified by an "uint32_t" in network
3289 byte order. This list is terminated by an "(uint32_t)0".
3290 Immediately after the terminating 0 follow the images, one by
3291 one, all aligned on "uint32_t" boundaries (size rounded up to
3292 a multiple of 4 bytes).
3294 "Firmware Images" are binary images containing firmware (like
3295 U-Boot or FPGA images) which usually will be programmed to
3298 "Script files" are command sequences that will be executed by
3299 U-Boot's command interpreter; this feature is especially
3300 useful when you configure U-Boot to use a real shell (hush)
3301 as command interpreter.
3307 One of the features of U-Boot is that you can dynamically load and
3308 run "standalone" applications, which can use some resources of
3309 U-Boot like console I/O functions or interrupt services.
3311 Two simple examples are included with the sources:
3316 'examples/hello_world.c' contains a small "Hello World" Demo
3317 application; it is automatically compiled when you build U-Boot.
3318 It's configured to run at address 0x00040004, so you can play with it
3322 ## Ready for S-Record download ...
3323 ~>examples/hello_world.srec
3324 1 2 3 4 5 6 7 8 9 10 11 ...
3325 [file transfer complete]
3327 ## Start Addr = 0x00040004
3329 => go 40004 Hello World! This is a test.
3330 ## Starting application at 0x00040004 ...
3341 Hit any key to exit ...
3343 ## Application terminated, rc = 0x0
3345 Another example, which demonstrates how to register a CPM interrupt
3346 handler with the U-Boot code, can be found in 'examples/timer.c'.
3347 Here, a CPM timer is set up to generate an interrupt every second.
3348 The interrupt service routine is trivial, just printing a '.'
3349 character, but this is just a demo program. The application can be
3350 controlled by the following keys:
3352 ? - print current values og the CPM Timer registers
3353 b - enable interrupts and start timer
3354 e - stop timer and disable interrupts
3355 q - quit application
3358 ## Ready for S-Record download ...
3359 ~>examples/timer.srec
3360 1 2 3 4 5 6 7 8 9 10 11 ...
3361 [file transfer complete]
3363 ## Start Addr = 0x00040004
3366 ## Starting application at 0x00040004 ...
3369 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3372 [q, b, e, ?] Set interval 1000000 us
3375 [q, b, e, ?] ........
3376 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3379 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3382 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3385 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3387 [q, b, e, ?] ...Stopping timer
3389 [q, b, e, ?] ## Application terminated, rc = 0x0
3395 Over time, many people have reported problems when trying to use the
3396 "minicom" terminal emulation program for serial download. I (wd)
3397 consider minicom to be broken, and recommend not to use it. Under
3398 Unix, I recommend to use C-Kermit for general purpose use (and
3399 especially for kermit binary protocol download ("loadb" command), and
3400 use "cu" for S-Record download ("loads" command).
3402 Nevertheless, if you absolutely want to use it try adding this
3403 configuration to your "File transfer protocols" section:
3405 Name Program Name U/D FullScr IO-Red. Multi
3406 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3407 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3413 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3414 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3416 Building requires a cross environment; it is known to work on
3417 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3418 need gmake since the Makefiles are not compatible with BSD make).
3419 Note that the cross-powerpc package does not install include files;
3420 attempting to build U-Boot will fail because <machine/ansi.h> is
3421 missing. This file has to be installed and patched manually:
3423 # cd /usr/pkg/cross/powerpc-netbsd/include
3425 # ln -s powerpc machine
3426 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3427 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3429 Native builds *don't* work due to incompatibilities between native
3430 and U-Boot include files.
3432 Booting assumes that (the first part of) the image booted is a
3433 stage-2 loader which in turn loads and then invokes the kernel
3434 proper. Loader sources will eventually appear in the NetBSD source
3435 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3436 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3439 Implementation Internals:
3440 =========================
3442 The following is not intended to be a complete description of every
3443 implementation detail. However, it should help to understand the
3444 inner workings of U-Boot and make it easier to port it to custom
3448 Initial Stack, Global Data:
3449 ---------------------------
3451 The implementation of U-Boot is complicated by the fact that U-Boot
3452 starts running out of ROM (flash memory), usually without access to
3453 system RAM (because the memory controller is not initialized yet).
3454 This means that we don't have writable Data or BSS segments, and BSS
3455 is not initialized as zero. To be able to get a C environment working
3456 at all, we have to allocate at least a minimal stack. Implementation
3457 options for this are defined and restricted by the CPU used: Some CPU
3458 models provide on-chip memory (like the IMMR area on MPC8xx and
3459 MPC826x processors), on others (parts of) the data cache can be
3460 locked as (mis-) used as memory, etc.
3462 Chris Hallinan posted a good summary of these issues to the
3463 u-boot-users mailing list:
3465 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3466 From: "Chris Hallinan" <clh@net1plus.com>
3467 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3470 Correct me if I'm wrong, folks, but the way I understand it
3471 is this: Using DCACHE as initial RAM for Stack, etc, does not
3472 require any physical RAM backing up the cache. The cleverness
3473 is that the cache is being used as a temporary supply of
3474 necessary storage before the SDRAM controller is setup. It's
3475 beyond the scope of this list to expain the details, but you
3476 can see how this works by studying the cache architecture and
3477 operation in the architecture and processor-specific manuals.
3479 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3480 is another option for the system designer to use as an
3481 initial stack/ram area prior to SDRAM being available. Either
3482 option should work for you. Using CS 4 should be fine if your
3483 board designers haven't used it for something that would
3484 cause you grief during the initial boot! It is frequently not
3487 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3488 with your processor/board/system design. The default value
3489 you will find in any recent u-boot distribution in
3490 walnut.h should work for you. I'd set it to a value larger
3491 than your SDRAM module. If you have a 64MB SDRAM module, set
3492 it above 400_0000. Just make sure your board has no resources
3493 that are supposed to respond to that address! That code in
3494 start.S has been around a while and should work as is when
3495 you get the config right.
3500 It is essential to remember this, since it has some impact on the C
3501 code for the initialization procedures:
3503 * Initialized global data (data segment) is read-only. Do not attempt
3506 * Do not use any unitialized global data (or implicitely initialized
3507 as zero data - BSS segment) at all - this is undefined, initiali-
3508 zation is performed later (when relocating to RAM).
3510 * Stack space is very limited. Avoid big data buffers or things like
3513 Having only the stack as writable memory limits means we cannot use
3514 normal global data to share information beween the code. But it
3515 turned out that the implementation of U-Boot can be greatly
3516 simplified by making a global data structure (gd_t) available to all
3517 functions. We could pass a pointer to this data as argument to _all_
3518 functions, but this would bloat the code. Instead we use a feature of
3519 the GCC compiler (Global Register Variables) to share the data: we
3520 place a pointer (gd) to the global data into a register which we
3521 reserve for this purpose.
3523 When choosing a register for such a purpose we are restricted by the
3524 relevant (E)ABI specifications for the current architecture, and by
3525 GCC's implementation.
3527 For PowerPC, the following registers have specific use:
3530 R3-R4: parameter passing and return values
3531 R5-R10: parameter passing
3532 R13: small data area pointer
3536 (U-Boot also uses R14 as internal GOT pointer.)
3538 ==> U-Boot will use R29 to hold a pointer to the global data
3540 Note: on PPC, we could use a static initializer (since the
3541 address of the global data structure is known at compile time),
3542 but it turned out that reserving a register results in somewhat
3543 smaller code - although the code savings are not that big (on
3544 average for all boards 752 bytes for the whole U-Boot image,
3545 624 text + 127 data).
3547 On ARM, the following registers are used:
3549 R0: function argument word/integer result
3550 R1-R3: function argument word
3552 R10: stack limit (used only if stack checking if enabled)
3553 R11: argument (frame) pointer
3554 R12: temporary workspace
3557 R15: program counter
3559 ==> U-Boot will use R8 to hold a pointer to the global data
3561 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3562 or current versions of GCC may "optimize" the code too much.
3567 U-Boot runs in system state and uses physical addresses, i.e. the
3568 MMU is not used either for address mapping nor for memory protection.
3570 The available memory is mapped to fixed addresses using the memory
3571 controller. In this process, a contiguous block is formed for each
3572 memory type (Flash, SDRAM, SRAM), even when it consists of several
3573 physical memory banks.
3575 U-Boot is installed in the first 128 kB of the first Flash bank (on
3576 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3577 booting and sizing and initializing DRAM, the code relocates itself
3578 to the upper end of DRAM. Immediately below the U-Boot code some
3579 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3580 configuration setting]. Below that, a structure with global Board
3581 Info data is placed, followed by the stack (growing downward).
3583 Additionally, some exception handler code is copied to the low 8 kB
3584 of DRAM (0x00000000 ... 0x00001FFF).
3586 So a typical memory configuration with 16 MB of DRAM could look like
3589 0x0000 0000 Exception Vector code
3592 0x0000 2000 Free for Application Use
3598 0x00FB FF20 Monitor Stack (Growing downward)
3599 0x00FB FFAC Board Info Data and permanent copy of global data
3600 0x00FC 0000 Malloc Arena
3603 0x00FE 0000 RAM Copy of Monitor Code
3604 ... eventually: LCD or video framebuffer
3605 ... eventually: pRAM (Protected RAM - unchanged by reset)
3606 0x00FF FFFF [End of RAM]
3609 System Initialization:
3610 ----------------------
3612 In the reset configuration, U-Boot starts at the reset entry point
3613 (on most PowerPC systens at address 0x00000100). Because of the reset
3614 configuration for CS0# this is a mirror of the onboard Flash memory.
3615 To be able to re-map memory U-Boot then jumps to its link address.
3616 To be able to implement the initialization code in C, a (small!)
3617 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3618 which provide such a feature like MPC8xx or MPC8260), or in a locked
3619 part of the data cache. After that, U-Boot initializes the CPU core,
3620 the caches and the SIU.
3622 Next, all (potentially) available memory banks are mapped using a
3623 preliminary mapping. For example, we put them on 512 MB boundaries
3624 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3625 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3626 programmed for SDRAM access. Using the temporary configuration, a
3627 simple memory test is run that determines the size of the SDRAM
3630 When there is more than one SDRAM bank, and the banks are of
3631 different size, the largest is mapped first. For equal size, the first
3632 bank (CS2#) is mapped first. The first mapping is always for address
3633 0x00000000, with any additional banks following immediately to create
3634 contiguous memory starting from 0.
3636 Then, the monitor installs itself at the upper end of the SDRAM area
3637 and allocates memory for use by malloc() and for the global Board
3638 Info data; also, the exception vector code is copied to the low RAM
3639 pages, and the final stack is set up.
3641 Only after this relocation will you have a "normal" C environment;
3642 until that you are restricted in several ways, mostly because you are
3643 running from ROM, and because the code will have to be relocated to a
3647 U-Boot Porting Guide:
3648 ----------------------
3650 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3654 int main (int argc, char *argv[])
3656 sighandler_t no_more_time;
3658 signal (SIGALRM, no_more_time);
3659 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3661 if (available_money > available_manpower) {
3662 pay consultant to port U-Boot;
3666 Download latest U-Boot source;
3668 Subscribe to u-boot-users mailing list;
3671 email ("Hi, I am new to U-Boot, how do I get started?");
3675 Read the README file in the top level directory;
3676 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3677 Read the source, Luke;
3680 if (available_money > toLocalCurrency ($2500)) {
3683 Add a lot of aggravation and time;
3686 Create your own board support subdirectory;
3688 Create your own board config file;
3692 Add / modify source code;
3696 email ("Hi, I am having problems...");
3698 Send patch file to Wolfgang;
3703 void no_more_time (int sig)
3712 All contributions to U-Boot should conform to the Linux kernel
3713 coding style; see the file "Documentation/CodingStyle" and the script
3714 "scripts/Lindent" in your Linux kernel source directory. In sources
3715 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3716 spaces before parameters to function calls) is actually used.
3718 Source files originating from a different project (for example the
3719 MTD subsystem) are generally exempt from these guidelines and are not
3720 reformated to ease subsequent migration to newer versions of those
3723 Please note that U-Boot is implemented in C (and to some small parts in
3724 Assembler); no C++ is used, so please do not use C++ style comments (//)
3727 Please also stick to the following formatting rules:
3728 - remove any trailing white space
3729 - use TAB characters for indentation, not spaces
3730 - make sure NOT to use DOS '\r\n' line feeds
3731 - do not add more than 2 empty lines to source files
3732 - do not add trailing empty lines to source files
3734 Submissions which do not conform to the standards may be returned
3735 with a request to reformat the changes.
3741 Since the number of patches for U-Boot is growing, we need to
3742 establish some rules. Submissions which do not conform to these rules
3743 may be rejected, even when they contain important and valuable stuff.
3745 Patches shall be sent to the u-boot-users mailing list.
3747 When you send a patch, please include the following information with
3750 * For bug fixes: a description of the bug and how your patch fixes
3751 this bug. Please try to include a way of demonstrating that the
3752 patch actually fixes something.
3754 * For new features: a description of the feature and your
3757 * A CHANGELOG entry as plaintext (separate from the patch)
3759 * For major contributions, your entry to the CREDITS file
3761 * When you add support for a new board, don't forget to add this
3762 board to the MAKEALL script, too.
3764 * If your patch adds new configuration options, don't forget to
3765 document these in the README file.
3767 * The patch itself. If you are accessing the CVS repository use "cvs
3768 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3769 version of diff does not support these options, then get the latest
3770 version of GNU diff.
3772 The current directory when running this command shall be the top
3773 level directory of the U-Boot source tree, or it's parent directory
3774 (i. e. please make sure that your patch includes sufficient
3775 directory information for the affected files).
3777 We accept patches as plain text, MIME attachments or as uuencoded
3780 * If one logical set of modifications affects or creates several
3781 files, all these changes shall be submitted in a SINGLE patch file.
3783 * Changesets that contain different, unrelated modifications shall be
3784 submitted as SEPARATE patches, one patch per changeset.
3789 * Before sending the patch, run the MAKEALL script on your patched
3790 source tree and make sure that no errors or warnings are reported
3791 for any of the boards.
3793 * Keep your modifications to the necessary minimum: A patch
3794 containing several unrelated changes or arbitrary reformats will be
3795 returned with a request to re-formatting / split it.
3797 * If you modify existing code, make sure that your new code does not
3798 add to the memory footprint of the code ;-) Small is beautiful!
3799 When adding new features, these should compile conditionally only
3800 (using #ifdef), and the resulting code with the new feature
3801 disabled must not need more memory than the old code without your
3804 * Remember that there is a size limit of 40 kB per message on the
3805 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob