2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - libfdt Library files to support flattened device trees
168 - net Networking code
169 - post Power On Self Test
170 - rtc Real Time Clock drivers
171 - tools Tools to build S-Record or U-Boot images, etc.
173 Software Configuration:
174 =======================
176 Configuration is usually done using C preprocessor defines; the
177 rationale behind that is to avoid dead code whenever possible.
179 There are two classes of configuration variables:
181 * Configuration _OPTIONS_:
182 These are selectable by the user and have names beginning with
185 * Configuration _SETTINGS_:
186 These depend on the hardware etc. and should not be meddled with if
187 you don't know what you're doing; they have names beginning with
190 Later we will add a configuration tool - probably similar to or even
191 identical to what's used for the Linux kernel. Right now, we have to
192 do the configuration by hand, which means creating some symbolic
193 links and editing some configuration files. We use the TQM8xxL boards
197 Selection of Processor Architecture and Board Type:
198 ---------------------------------------------------
200 For all supported boards there are ready-to-use default
201 configurations available; just type "make <board_name>_config".
203 Example: For a TQM823L module type:
208 For the Cogent platform, you need to specify the cpu type as well;
209 e.g. "make cogent_mpc8xx_config". And also configure the cogent
210 directory according to the instructions in cogent/README.
213 Configuration Options:
214 ----------------------
216 Configuration depends on the combination of board and CPU type; all
217 such information is kept in a configuration file
218 "include/configs/<board_name>.h".
220 Example: For a TQM823L module, all configuration settings are in
221 "include/configs/TQM823L.h".
224 Many of the options are named exactly as the corresponding Linux
225 kernel configuration options. The intention is to make it easier to
226 build a config tool - later.
229 The following options need to be configured:
231 - CPU Type: Define exactly one of
235 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
238 or CONFIG_MPC824X, CONFIG_MPC8260
255 MicroBlaze based CPUs:
256 ----------------------
260 ----------------------
264 ----------------------
267 - Board Type: Define exactly one of
269 PowerPC based boards:
270 ---------------------
272 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
273 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
274 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
275 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
276 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
277 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
278 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
279 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
280 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
281 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
282 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
283 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
284 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
285 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
286 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
287 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
288 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
289 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
290 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
291 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
292 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
293 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
294 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
295 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
296 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
297 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
298 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
299 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
300 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
301 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
302 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
303 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
304 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
305 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
306 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
307 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
308 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
309 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
314 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
315 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
316 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
317 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
318 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
319 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
320 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
321 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
324 MicroBlaze based boards:
325 ------------------------
330 ------------------------
332 CONFIG_PCI5441 CONFIG_PK1C20
333 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
340 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
341 Define exactly one of
345 - CPU Module Type: (if CONFIG_COGENT is defined)
346 Define exactly one of
348 --- FIXME --- not tested yet:
349 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
350 CONFIG_CMA287_23, CONFIG_CMA287_50
352 - Motherboard Type: (if CONFIG_COGENT is defined)
353 Define exactly one of
354 CONFIG_CMA101, CONFIG_CMA102
356 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
357 Define one or more of
360 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
361 Define one or more of
362 CONFIG_LCD_HEARTBEAT - update a character position on
363 the lcd display every second with
366 - Board flavour: (if CONFIG_MPC8260ADS is defined)
369 CFG_8260ADS - original MPC8260ADS
370 CFG_8266ADS - MPC8266ADS
371 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
372 CFG_8272ADS - MPC8272ADS
374 - MPC824X Family Member (if CONFIG_MPC824X is defined)
375 Define exactly one of
376 CONFIG_MPC8240, CONFIG_MPC8245
378 - 8xx CPU Options: (if using an MPC8xx cpu)
379 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
380 get_gclk_freq() cannot work
381 e.g. if there is no 32KHz
382 reference PIT/RTC clock
383 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
386 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
389 CONFIG_8xx_CPUCLK_DEFAULT
390 See doc/README.MPC866
394 Define this to measure the actual CPU clock instead
395 of relying on the correctness of the configured
396 values. Mostly useful for board bringup to make sure
397 the PLL is locked at the intended frequency. Note
398 that this requires a (stable) reference clock (32 kHz
399 RTC clock or CFG_8XX_XIN)
401 - Intel Monahans options:
402 CFG_MONAHANS_RUN_MODE_OSC_RATIO
404 Defines the Monahans run mode to oscillator
405 ratio. Valid values are 8, 16, 24, 31. The core
406 frequency is this value multiplied by 13 MHz.
408 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
410 Defines the Monahans turbo mode to oscillator
411 ratio. Valid values are 1 (default if undefined) and
412 2. The core frequency as calculated above is multiplied
415 - Linux Kernel Interface:
418 U-Boot stores all clock information in Hz
419 internally. For binary compatibility with older Linux
420 kernels (which expect the clocks passed in the
421 bd_info data to be in MHz) the environment variable
422 "clocks_in_mhz" can be defined so that U-Boot
423 converts clock data to MHZ before passing it to the
425 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
426 "clocks_in_mhz=1" is automatically included in the
429 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
431 When transfering memsize parameter to linux, some versions
432 expect it to be in bytes, others in MB.
433 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
435 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
437 New kernel versions are expecting firmware settings to be
438 passed using flattened device trees (based on open firmware
442 * New libfdt-based support
443 * Adds the "fdt" command
444 * The bootm command does _not_ modify the fdt
447 * Deprecated, see CONFIG_OF_LIBFDT
448 * Original ft_build.c-based support
449 * Automatically modifies the dft as part of the bootm command
450 * The environment variable "disable_of", when set,
451 disables this functionality.
453 CONFIG_OF_FLAT_TREE_MAX_SIZE
455 The maximum size of the constructed OF tree.
457 OF_CPU - The proper name of the cpus node.
458 OF_SOC - The proper name of the soc node.
459 OF_TBCLK - The timebase frequency.
460 OF_STDOUT_PATH - The path to the console device
464 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
465 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
466 will have a copy of the bd_t. Space should be
467 pre-allocated in the dts for the bd_t.
469 CONFIG_OF_HAS_UBOOT_ENV
471 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
472 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
473 will have a copy of u-boot's environment variables
475 CONFIG_OF_BOARD_SETUP
477 Board code has addition modification that it wants to make
478 to the flat device tree before handing it off to the kernel
482 This define fills in the correct boot cpu in the boot
483 param header, the default value is zero if undefined.
488 Define this if you want support for Amba PrimeCell PL010 UARTs.
492 Define this if you want support for Amba PrimeCell PL011 UARTs.
496 If you have Amba PrimeCell PL011 UARTs, set this variable to
497 the clock speed of the UARTs.
501 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
502 define this to a list of base addresses for each (supported)
503 port. See e.g. include/configs/versatile.h
507 Depending on board, define exactly one serial port
508 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
509 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
510 console by defining CONFIG_8xx_CONS_NONE
512 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
513 port routines must be defined elsewhere
514 (i.e. serial_init(), serial_getc(), ...)
517 Enables console device for a color framebuffer. Needs following
518 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
519 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
521 VIDEO_HW_RECTFILL graphic chip supports
524 VIDEO_HW_BITBLT graphic chip supports
525 bit-blit (cf. smiLynxEM)
526 VIDEO_VISIBLE_COLS visible pixel columns
528 VIDEO_VISIBLE_ROWS visible pixel rows
529 VIDEO_PIXEL_SIZE bytes per pixel
530 VIDEO_DATA_FORMAT graphic data format
531 (0-5, cf. cfb_console.c)
532 VIDEO_FB_ADRS framebuffer address
533 VIDEO_KBD_INIT_FCT keyboard int fct
534 (i.e. i8042_kbd_init())
535 VIDEO_TSTC_FCT test char fct
537 VIDEO_GETC_FCT get char fct
539 CONFIG_CONSOLE_CURSOR cursor drawing on/off
540 (requires blink timer
542 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
543 CONFIG_CONSOLE_TIME display time/date info in
545 (requires CFG_CMD_DATE)
546 CONFIG_VIDEO_LOGO display Linux logo in
548 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
549 linux_logo.h for logo.
550 Requires CONFIG_VIDEO_LOGO
551 CONFIG_CONSOLE_EXTRA_INFO
552 addional board info beside
555 When CONFIG_CFB_CONSOLE is defined, video console is
556 default i/o. Serial console can be forced with
557 environment 'console=serial'.
559 When CONFIG_SILENT_CONSOLE is defined, all console
560 messages (by U-Boot and Linux!) can be silenced with
561 the "silent" environment variable. See
562 doc/README.silent for more information.
565 CONFIG_BAUDRATE - in bps
566 Select one of the baudrates listed in
567 CFG_BAUDRATE_TABLE, see below.
568 CFG_BRGCLK_PRESCALE, baudrate prescale
570 - Interrupt driven serial port input:
571 CONFIG_SERIAL_SOFTWARE_FIFO
574 Use an interrupt handler for receiving data on the
575 serial port. It also enables using hardware handshake
576 (RTS/CTS) and UART's built-in FIFO. Set the number of
577 bytes the interrupt driven input buffer should have.
579 Leave undefined to disable this feature, including
580 disable the buffer and hardware handshake.
582 - Console UART Number:
586 If defined internal UART1 (and not UART0) is used
587 as default U-Boot console.
589 - Boot Delay: CONFIG_BOOTDELAY - in seconds
590 Delay before automatically booting the default image;
591 set to -1 to disable autoboot.
593 See doc/README.autoboot for these options that
594 work with CONFIG_BOOTDELAY. None are required.
595 CONFIG_BOOT_RETRY_TIME
596 CONFIG_BOOT_RETRY_MIN
597 CONFIG_AUTOBOOT_KEYED
598 CONFIG_AUTOBOOT_PROMPT
599 CONFIG_AUTOBOOT_DELAY_STR
600 CONFIG_AUTOBOOT_STOP_STR
601 CONFIG_AUTOBOOT_DELAY_STR2
602 CONFIG_AUTOBOOT_STOP_STR2
603 CONFIG_ZERO_BOOTDELAY_CHECK
604 CONFIG_RESET_TO_RETRY
608 Only needed when CONFIG_BOOTDELAY is enabled;
609 define a command string that is automatically executed
610 when no character is read on the console interface
611 within "Boot Delay" after reset.
614 This can be used to pass arguments to the bootm
615 command. The value of CONFIG_BOOTARGS goes into the
616 environment value "bootargs".
618 CONFIG_RAMBOOT and CONFIG_NFSBOOT
619 The value of these goes into the environment as
620 "ramboot" and "nfsboot" respectively, and can be used
621 as a convenience, when switching between booting from
627 When this option is #defined, the existence of the
628 environment variable "preboot" will be checked
629 immediately before starting the CONFIG_BOOTDELAY
630 countdown and/or running the auto-boot command resp.
631 entering interactive mode.
633 This feature is especially useful when "preboot" is
634 automatically generated or modified. For an example
635 see the LWMON board specific code: here "preboot" is
636 modified when the user holds down a certain
637 combination of keys on the (special) keyboard when
640 - Serial Download Echo Mode:
642 If defined to 1, all characters received during a
643 serial download (using the "loads" command) are
644 echoed back. This might be needed by some terminal
645 emulations (like "cu"), but may as well just take
646 time on others. This setting #define's the initial
647 value of the "loads_echo" environment variable.
649 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
651 Select one of the baudrates listed in
652 CFG_BAUDRATE_TABLE, see below.
656 Most monitor functions can be selected (or
657 de-selected) by adjusting the definition of
658 CONFIG_COMMANDS; to select individual functions,
659 #define CONFIG_COMMANDS by "OR"ing any of the
662 #define enables commands:
663 -------------------------
664 CFG_CMD_ASKENV * ask for env variable
665 CFG_CMD_AUTOSCRIPT Autoscript Support
667 CFG_CMD_BEDBUG * Include BedBug Debugger
668 CFG_CMD_BMP * BMP support
669 CFG_CMD_BSP * Board specific commands
671 CFG_CMD_CACHE * icache, dcache
672 CFG_CMD_CONSOLE coninfo
673 CFG_CMD_DATE * support for RTC, date/time...
674 CFG_CMD_DHCP * DHCP support
675 CFG_CMD_DIAG * Diagnostics
676 CFG_CMD_DOC * Disk-On-Chip Support
677 CFG_CMD_DTT * Digital Therm and Thermostat
678 CFG_CMD_ECHO echo arguments
679 CFG_CMD_EEPROM * EEPROM read/write support
680 CFG_CMD_ELF * bootelf, bootvx
682 CFG_CMD_FDC * Floppy Disk Support
683 CFG_CMD_FAT * FAT partition support
684 CFG_CMD_FDOS * Dos diskette Support
685 CFG_CMD_FLASH flinfo, erase, protect
686 CFG_CMD_FPGA FPGA device initialization support
687 CFG_CMD_HWFLOW * RTS/CTS hw flow control
688 CFG_CMD_I2C * I2C serial bus support
689 CFG_CMD_IDE * IDE harddisk support
691 CFG_CMD_IMLS List all found images
692 CFG_CMD_IMMAP * IMMR dump support
693 CFG_CMD_IRQ * irqinfo
694 CFG_CMD_ITEST Integer/string test of 2 values
695 CFG_CMD_JFFS2 * JFFS2 Support
699 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
701 CFG_CMD_MISC Misc functions like sleep etc
702 CFG_CMD_MMC * MMC memory mapped support
703 CFG_CMD_MII * MII utility commands
704 CFG_CMD_NAND * NAND support
705 CFG_CMD_NET bootp, tftpboot, rarpboot
706 CFG_CMD_PCI * pciinfo
707 CFG_CMD_PCMCIA * PCMCIA support
708 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
709 CFG_CMD_PORTIO * Port I/O
710 CFG_CMD_REGINFO * Register dump
711 CFG_CMD_RUN run command in env variable
712 CFG_CMD_SAVES * save S record dump
713 CFG_CMD_SCSI * SCSI Support
714 CFG_CMD_SDRAM * print SDRAM configuration information
715 (requires CFG_CMD_I2C)
716 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
717 CFG_CMD_SPI * SPI serial bus support
718 CFG_CMD_USB * USB support
719 CFG_CMD_VFD * VFD support (TRAB)
720 CFG_CMD_BSP * Board SPecific functions
721 CFG_CMD_CDP * Cisco Discover Protocol support
722 -----------------------------------------------
725 CONFIG_CMD_DFL Default configuration; at the moment
726 this is includes all commands, except
727 the ones marked with "*" in the list
730 If you don't define CONFIG_COMMANDS it defaults to
731 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
732 override the default settings in the respective
735 EXAMPLE: If you want all functions except of network
736 support you can write:
738 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
741 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
743 Note: Don't enable the "icache" and "dcache" commands
744 (configuration option CFG_CMD_CACHE) unless you know
745 what you (and your U-Boot users) are doing. Data
746 cache cannot be enabled on systems like the 8xx or
747 8260 (where accesses to the IMMR region must be
748 uncached), and it cannot be disabled on all other
749 systems where we (mis-) use the data cache to hold an
750 initial stack and some data.
753 XXX - this list needs to get updated!
757 If this variable is defined, it enables watchdog
758 support. There must be support in the platform specific
759 code for a watchdog. For the 8xx and 8260 CPUs, the
760 SIU Watchdog feature is enabled in the SYPCR
764 CONFIG_VERSION_VARIABLE
765 If this variable is defined, an environment variable
766 named "ver" is created by U-Boot showing the U-Boot
767 version as printed by the "version" command.
768 This variable is readonly.
772 When CFG_CMD_DATE is selected, the type of the RTC
773 has to be selected, too. Define exactly one of the
776 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
777 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
778 CONFIG_RTC_MC146818 - use MC146818 RTC
779 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
780 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
781 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
782 CONFIG_RTC_DS164x - use Dallas DS164x RTC
783 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
785 Note that if the RTC uses I2C, then the I2C interface
786 must also be configured. See I2C Support, below.
790 When CONFIG_TIMESTAMP is selected, the timestamp
791 (date and time) of an image is printed by image
792 commands like bootm or iminfo. This option is
793 automatically enabled when you select CFG_CMD_DATE .
796 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
797 and/or CONFIG_ISO_PARTITION
799 If IDE or SCSI support is enabled (CFG_CMD_IDE or
800 CFG_CMD_SCSI) you must configure support for at least
801 one partition type as well.
804 CONFIG_IDE_RESET_ROUTINE - this is defined in several
805 board configurations files but used nowhere!
807 CONFIG_IDE_RESET - is this is defined, IDE Reset will
808 be performed by calling the function
809 ide_set_reset(int reset)
810 which has to be defined in a board specific file
815 Set this to enable ATAPI support.
820 Set this to enable support for disks larger than 137GB
821 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
822 Whithout these , LBA48 support uses 32bit variables and will 'only'
823 support disks up to 2.1TB.
826 When enabled, makes the IDE subsystem use 64bit sector addresses.
830 At the moment only there is only support for the
831 SYM53C8XX SCSI controller; define
832 CONFIG_SCSI_SYM53C8XX to enable it.
834 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
835 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
836 CFG_SCSI_MAX_LUN] can be adjusted to define the
837 maximum numbers of LUNs, SCSI ID's and target
839 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
841 - NETWORK Support (PCI):
843 Support for Intel 8254x gigabit chips.
846 Support for Intel 82557/82559/82559ER chips.
847 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
848 write routine for first time initialisation.
851 Support for Digital 2114x chips.
852 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
853 modem chip initialisation (KS8761/QS6611).
856 Support for National dp83815 chips.
859 Support for National dp8382[01] gigabit chips.
861 - NETWORK Support (other):
863 CONFIG_DRIVER_LAN91C96
864 Support for SMSC's LAN91C96 chips.
867 Define this to hold the physical address
868 of the LAN91C96's I/O space
870 CONFIG_LAN91C96_USE_32_BIT
871 Define this to enable 32 bit addressing
873 CONFIG_DRIVER_SMC91111
874 Support for SMSC's LAN91C111 chip
877 Define this to hold the physical address
878 of the device (I/O space)
880 CONFIG_SMC_USE_32_BIT
881 Define this if data bus is 32 bits
883 CONFIG_SMC_USE_IOFUNCS
884 Define this to use i/o functions instead of macros
885 (some hardware wont work with macros)
888 At the moment only the UHCI host controller is
889 supported (PIP405, MIP405, MPC5200); define
890 CONFIG_USB_UHCI to enable it.
891 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
892 and define CONFIG_USB_STORAGE to enable the USB
895 Supported are USB Keyboards and USB Floppy drives
897 MPC5200 USB requires additional defines:
899 for 528 MHz Clock: 0x0001bbbb
901 for differential drivers: 0x00001000
902 for single ended drivers: 0x00005000
905 Define the below if you wish to use the USB console.
906 Once firmware is rebuilt from a serial console issue the
907 command "setenv stdin usbtty; setenv stdout usbtty" and
908 attach your usb cable. The Unix command "dmesg" should print
909 it has found a new device. The environment variable usbtty
910 can be set to gserial or cdc_acm to enable your device to
911 appear to a USB host as a Linux gserial device or a
912 Common Device Class Abstract Control Model serial device.
913 If you select usbtty = gserial you should be able to enumerate
915 # modprobe usbserial vendor=0xVendorID product=0xProductID
916 else if using cdc_acm, simply setting the environment
917 variable usbtty to be cdc_acm should suffice. The following
918 might be defined in YourBoardName.h
921 Define this to build a UDC device
924 Define this to have a tty type of device available to
925 talk to the UDC device
927 CFG_CONSOLE_IS_IN_ENV
928 Define this if you want stdin, stdout &/or stderr to
932 CFG_USB_EXTC_CLK 0xBLAH
933 Derive USB clock from external clock "blah"
934 - CFG_USB_EXTC_CLK 0x02
936 CFG_USB_BRG_CLK 0xBLAH
937 Derive USB clock from brgclk
938 - CFG_USB_BRG_CLK 0x04
940 If you have a USB-IF assigned VendorID then you may wish to
941 define your own vendor specific values either in BoardName.h
942 or directly in usbd_vendor_info.h. If you don't define
943 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
944 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
945 should pretend to be a Linux device to it's target host.
947 CONFIG_USBD_MANUFACTURER
948 Define this string as the name of your company for
949 - CONFIG_USBD_MANUFACTURER "my company"
951 CONFIG_USBD_PRODUCT_NAME
952 Define this string as the name of your product
953 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
956 Define this as your assigned Vendor ID from the USB
957 Implementors Forum. This *must* be a genuine Vendor ID
958 to avoid polluting the USB namespace.
959 - CONFIG_USBD_VENDORID 0xFFFF
961 CONFIG_USBD_PRODUCTID
962 Define this as the unique Product ID
964 - CONFIG_USBD_PRODUCTID 0xFFFF
968 The MMC controller on the Intel PXA is supported. To
969 enable this define CONFIG_MMC. The MMC can be
970 accessed from the boot prompt by mapping the device
971 to physical memory similar to flash. Command line is
972 enabled with CFG_CMD_MMC. The MMC driver also works with
973 the FAT fs. This is enabled with CFG_CMD_FAT.
975 - Journaling Flash filesystem support:
976 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
977 CONFIG_JFFS2_NAND_DEV
978 Define these for a default partition on a NAND device
980 CFG_JFFS2_FIRST_SECTOR,
981 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
982 Define these for a default partition on a NOR device
985 Define this to create an own partition. You have to provide a
986 function struct part_info* jffs2_part_info(int part_num)
988 If you define only one JFFS2 partition you may also want to
989 #define CFG_JFFS_SINGLE_PART 1
990 to disable the command chpart. This is the default when you
991 have not defined a custom partition
996 Define this to enable standard (PC-Style) keyboard
1000 Standard PC keyboard driver with US (is default) and
1001 GERMAN key layout (switch via environment 'keymap=de') support.
1002 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1003 for cfb_console. Supports cursor blinking.
1008 Define this to enable video support (for output to
1011 CONFIG_VIDEO_CT69000
1013 Enable Chips & Technologies 69000 Video chip
1015 CONFIG_VIDEO_SMI_LYNXEM
1016 Enable Silicon Motion SMI 712/710/810 Video chip. The
1017 video output is selected via environment 'videoout'
1018 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1021 For the CT69000 and SMI_LYNXEM drivers, videomode is
1022 selected via environment 'videomode'. Two diferent ways
1024 - "videomode=num" 'num' is a standard LiLo mode numbers.
1025 Following standard modes are supported (* is default):
1027 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1028 -------------+---------------------------------------------
1029 8 bits | 0x301* 0x303 0x305 0x161 0x307
1030 15 bits | 0x310 0x313 0x316 0x162 0x319
1031 16 bits | 0x311 0x314 0x317 0x163 0x31A
1032 24 bits | 0x312 0x315 0x318 ? 0x31B
1033 -------------+---------------------------------------------
1034 (i.e. setenv videomode 317; saveenv; reset;)
1036 - "videomode=bootargs" all the video parameters are parsed
1037 from the bootargs. (See drivers/videomodes.c)
1040 CONFIG_VIDEO_SED13806
1041 Enable Epson SED13806 driver. This driver supports 8bpp
1042 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1043 or CONFIG_VIDEO_SED13806_16BPP
1048 Define this to enable a custom keyboard support.
1049 This simply calls drv_keyboard_init() which must be
1050 defined in your board-specific files.
1051 The only board using this so far is RBC823.
1053 - LCD Support: CONFIG_LCD
1055 Define this to enable LCD support (for output to LCD
1056 display); also select one of the supported displays
1057 by defining one of these:
1059 CONFIG_NEC_NL6448AC33:
1061 NEC NL6448AC33-18. Active, color, single scan.
1063 CONFIG_NEC_NL6448BC20
1065 NEC NL6448BC20-08. 6.5", 640x480.
1066 Active, color, single scan.
1068 CONFIG_NEC_NL6448BC33_54
1070 NEC NL6448BC33-54. 10.4", 640x480.
1071 Active, color, single scan.
1075 Sharp 320x240. Active, color, single scan.
1076 It isn't 16x9, and I am not sure what it is.
1078 CONFIG_SHARP_LQ64D341
1080 Sharp LQ64D341 display, 640x480.
1081 Active, color, single scan.
1085 HLD1045 display, 640x480.
1086 Active, color, single scan.
1090 Optrex CBL50840-2 NF-FW 99 22 M5
1092 Hitachi LMG6912RPFC-00T
1096 320x240. Black & white.
1098 Normally display is black on white background; define
1099 CFG_WHITE_ON_BLACK to get it inverted.
1101 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1103 If this option is set, the environment is checked for
1104 a variable "splashimage". If found, the usual display
1105 of logo, copyright and system information on the LCD
1106 is suppressed and the BMP image at the address
1107 specified in "splashimage" is loaded instead. The
1108 console is redirected to the "nulldev", too. This
1109 allows for a "silent" boot where a splash screen is
1110 loaded very quickly after power-on.
1112 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1114 If this option is set, additionally to standard BMP
1115 images, gzipped BMP images can be displayed via the
1116 splashscreen support or the bmp command.
1118 - Compression support:
1121 If this option is set, support for bzip2 compressed
1122 images is included. If not, only uncompressed and gzip
1123 compressed images are supported.
1125 NOTE: the bzip2 algorithm requires a lot of RAM, so
1126 the malloc area (as defined by CFG_MALLOC_LEN) should
1132 The address of PHY on MII bus.
1134 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1136 The clock frequency of the MII bus
1140 If this option is set, support for speed/duplex
1141 detection of Gigabit PHY is included.
1143 CONFIG_PHY_RESET_DELAY
1145 Some PHY like Intel LXT971A need extra delay after
1146 reset before any MII register access is possible.
1147 For such PHY, set this option to the usec delay
1148 required. (minimum 300usec for LXT971A)
1150 CONFIG_PHY_CMD_DELAY (ppc4xx)
1152 Some PHY like Intel LXT971A need extra delay after
1153 command issued before MII status register can be read
1160 Define a default value for ethernet address to use
1161 for the respective ethernet interface, in case this
1162 is not determined automatically.
1167 Define a default value for the IP address to use for
1168 the default ethernet interface, in case this is not
1169 determined through e.g. bootp.
1171 - Server IP address:
1174 Defines a default value for theIP address of a TFTP
1175 server to contact when using the "tftboot" command.
1177 - BOOTP Recovery Mode:
1178 CONFIG_BOOTP_RANDOM_DELAY
1180 If you have many targets in a network that try to
1181 boot using BOOTP, you may want to avoid that all
1182 systems send out BOOTP requests at precisely the same
1183 moment (which would happen for instance at recovery
1184 from a power failure, when all systems will try to
1185 boot, thus flooding the BOOTP server. Defining
1186 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1187 inserted before sending out BOOTP requests. The
1188 following delays are insterted then:
1190 1st BOOTP request: delay 0 ... 1 sec
1191 2nd BOOTP request: delay 0 ... 2 sec
1192 3rd BOOTP request: delay 0 ... 4 sec
1194 BOOTP requests: delay 0 ... 8 sec
1196 - DHCP Advanced Options:
1199 You can fine tune the DHCP functionality by adding
1200 these flags to the CONFIG_BOOTP_MASK define:
1202 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1203 serverip from a DHCP server, it is possible that more
1204 than one DNS serverip is offered to the client.
1205 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1206 serverip will be stored in the additional environment
1207 variable "dnsip2". The first DNS serverip is always
1208 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1209 is added to the CONFIG_BOOTP_MASK.
1211 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1212 to do a dynamic update of a DNS server. To do this, they
1213 need the hostname of the DHCP requester.
1214 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1215 CONFIG_BOOTP_MASK, the content of the "hostname"
1216 environment variable is passed as option 12 to
1220 CONFIG_CDP_DEVICE_ID
1222 The device id used in CDP trigger frames.
1224 CONFIG_CDP_DEVICE_ID_PREFIX
1226 A two character string which is prefixed to the MAC address
1231 A printf format string which contains the ascii name of
1232 the port. Normally is set to "eth%d" which sets
1233 eth0 for the first ethernet, eth1 for the second etc.
1235 CONFIG_CDP_CAPABILITIES
1237 A 32bit integer which indicates the device capabilities;
1238 0x00000010 for a normal host which does not forwards.
1242 An ascii string containing the version of the software.
1246 An ascii string containing the name of the platform.
1250 A 32bit integer sent on the trigger.
1252 CONFIG_CDP_POWER_CONSUMPTION
1254 A 16bit integer containing the power consumption of the
1255 device in .1 of milliwatts.
1257 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1259 A byte containing the id of the VLAN.
1261 - Status LED: CONFIG_STATUS_LED
1263 Several configurations allow to display the current
1264 status using a LED. For instance, the LED will blink
1265 fast while running U-Boot code, stop blinking as
1266 soon as a reply to a BOOTP request was received, and
1267 start blinking slow once the Linux kernel is running
1268 (supported by a status LED driver in the Linux
1269 kernel). Defining CONFIG_STATUS_LED enables this
1272 - CAN Support: CONFIG_CAN_DRIVER
1274 Defining CONFIG_CAN_DRIVER enables CAN driver support
1275 on those systems that support this (optional)
1276 feature, like the TQM8xxL modules.
1278 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1280 These enable I2C serial bus commands. Defining either of
1281 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1282 include the appropriate I2C driver for the selected cpu.
1284 This will allow you to use i2c commands at the u-boot
1285 command line (as long as you set CFG_CMD_I2C in
1286 CONFIG_COMMANDS) and communicate with i2c based realtime
1287 clock chips. See common/cmd_i2c.c for a description of the
1288 command line interface.
1290 CONFIG_I2C_CMD_TREE is a recommended option that places
1291 all I2C commands under a single 'i2c' root command. The
1292 older 'imm', 'imd', 'iprobe' etc. commands are considered
1293 deprecated and may disappear in the future.
1295 CONFIG_HARD_I2C selects a hardware I2C controller.
1297 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1298 bit-banging) driver instead of CPM or similar hardware
1301 There are several other quantities that must also be
1302 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1304 In both cases you will need to define CFG_I2C_SPEED
1305 to be the frequency (in Hz) at which you wish your i2c bus
1306 to run and CFG_I2C_SLAVE to be the address of this node (ie
1307 the cpu's i2c node address).
1309 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1310 sets the cpu up as a master node and so its address should
1311 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1312 p.16-473). So, set CFG_I2C_SLAVE to 0.
1314 That's all that's required for CONFIG_HARD_I2C.
1316 If you use the software i2c interface (CONFIG_SOFT_I2C)
1317 then the following macros need to be defined (examples are
1318 from include/configs/lwmon.h):
1322 (Optional). Any commands necessary to enable the I2C
1323 controller or configure ports.
1325 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1329 (Only for MPC8260 CPU). The I/O port to use (the code
1330 assumes both bits are on the same port). Valid values
1331 are 0..3 for ports A..D.
1335 The code necessary to make the I2C data line active
1336 (driven). If the data line is open collector, this
1339 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1343 The code necessary to make the I2C data line tri-stated
1344 (inactive). If the data line is open collector, this
1347 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1351 Code that returns TRUE if the I2C data line is high,
1354 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1358 If <bit> is TRUE, sets the I2C data line high. If it
1359 is FALSE, it clears it (low).
1361 eg: #define I2C_SDA(bit) \
1362 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1363 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1367 If <bit> is TRUE, sets the I2C clock line high. If it
1368 is FALSE, it clears it (low).
1370 eg: #define I2C_SCL(bit) \
1371 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1372 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1376 This delay is invoked four times per clock cycle so this
1377 controls the rate of data transfer. The data rate thus
1378 is 1 / (I2C_DELAY * 4). Often defined to be something
1381 #define I2C_DELAY udelay(2)
1385 When a board is reset during an i2c bus transfer
1386 chips might think that the current transfer is still
1387 in progress. On some boards it is possible to access
1388 the i2c SCLK line directly, either by using the
1389 processor pin as a GPIO or by having a second pin
1390 connected to the bus. If this option is defined a
1391 custom i2c_init_board() routine in boards/xxx/board.c
1392 is run early in the boot sequence.
1394 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1396 This option enables configuration of bi_iic_fast[] flags
1397 in u-boot bd_info structure based on u-boot environment
1398 variable "i2cfast". (see also i2cfast)
1400 CONFIG_I2C_MULTI_BUS
1402 This option allows the use of multiple I2C buses, each of which
1403 must have a controller. At any point in time, only one bus is
1404 active. To switch to a different bus, use the 'i2c dev' command.
1405 Note that bus numbering is zero-based.
1409 This option specifies a list of I2C devices that will be skipped
1410 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1411 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1412 pairs. Otherwise, specify a 1D array of device addresses
1415 #undef CONFIG_I2C_MULTI_BUS
1416 #define CFG_I2C_NOPROBES {0x50,0x68}
1418 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1420 #define CONFIG_I2C_MULTI_BUS
1421 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1423 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1427 If defined, then this indicates the I2C bus number for DDR SPD.
1428 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1432 If defined, then this indicates the I2C bus number for the RTC.
1433 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1437 If defined, then this indicates the I2C bus number for the DTT.
1438 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1442 Define this option if you want to use Freescale's I2C driver in
1446 - SPI Support: CONFIG_SPI
1448 Enables SPI driver (so far only tested with
1449 SPI EEPROM, also an instance works with Crystal A/D and
1450 D/As on the SACSng board)
1454 Enables extended (16-bit) SPI EEPROM addressing.
1455 (symmetrical to CONFIG_I2C_X)
1459 Enables a software (bit-bang) SPI driver rather than
1460 using hardware support. This is a general purpose
1461 driver that only requires three general I/O port pins
1462 (two outputs, one input) to function. If this is
1463 defined, the board configuration must define several
1464 SPI configuration items (port pins to use, etc). For
1465 an example, see include/configs/sacsng.h.
1467 - FPGA Support: CONFIG_FPGA_COUNT
1469 Specify the number of FPGA devices to support.
1473 Used to specify the types of FPGA devices. For example,
1474 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1476 CFG_FPGA_PROG_FEEDBACK
1478 Enable printing of hash marks during FPGA configuration.
1482 Enable checks on FPGA configuration interface busy
1483 status by the configuration function. This option
1484 will require a board or device specific function to
1489 If defined, a function that provides delays in the FPGA
1490 configuration driver.
1492 CFG_FPGA_CHECK_CTRLC
1493 Allow Control-C to interrupt FPGA configuration
1495 CFG_FPGA_CHECK_ERROR
1497 Check for configuration errors during FPGA bitfile
1498 loading. For example, abort during Virtex II
1499 configuration if the INIT_B line goes low (which
1500 indicated a CRC error).
1504 Maximum time to wait for the INIT_B line to deassert
1505 after PROB_B has been deasserted during a Virtex II
1506 FPGA configuration sequence. The default time is 500
1511 Maximum time to wait for BUSY to deassert during
1512 Virtex II FPGA configuration. The default is 5 mS.
1514 CFG_FPGA_WAIT_CONFIG
1516 Time to wait after FPGA configuration. The default is
1519 - Configuration Management:
1522 If defined, this string will be added to the U-Boot
1523 version information (U_BOOT_VERSION)
1525 - Vendor Parameter Protection:
1527 U-Boot considers the values of the environment
1528 variables "serial#" (Board Serial Number) and
1529 "ethaddr" (Ethernet Address) to be parameters that
1530 are set once by the board vendor / manufacturer, and
1531 protects these variables from casual modification by
1532 the user. Once set, these variables are read-only,
1533 and write or delete attempts are rejected. You can
1534 change this behviour:
1536 If CONFIG_ENV_OVERWRITE is #defined in your config
1537 file, the write protection for vendor parameters is
1538 completely disabled. Anybody can change or delete
1541 Alternatively, if you #define _both_ CONFIG_ETHADDR
1542 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1543 ethernet address is installed in the environment,
1544 which can be changed exactly ONCE by the user. [The
1545 serial# is unaffected by this, i. e. it remains
1551 Define this variable to enable the reservation of
1552 "protected RAM", i. e. RAM which is not overwritten
1553 by U-Boot. Define CONFIG_PRAM to hold the number of
1554 kB you want to reserve for pRAM. You can overwrite
1555 this default value by defining an environment
1556 variable "pram" to the number of kB you want to
1557 reserve. Note that the board info structure will
1558 still show the full amount of RAM. If pRAM is
1559 reserved, a new environment variable "mem" will
1560 automatically be defined to hold the amount of
1561 remaining RAM in a form that can be passed as boot
1562 argument to Linux, for instance like that:
1564 setenv bootargs ... mem=\${mem}
1567 This way you can tell Linux not to use this memory,
1568 either, which results in a memory region that will
1569 not be affected by reboots.
1571 *WARNING* If your board configuration uses automatic
1572 detection of the RAM size, you must make sure that
1573 this memory test is non-destructive. So far, the
1574 following board configurations are known to be
1577 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1578 HERMES, IP860, RPXlite, LWMON, LANTEC,
1579 PCU_E, FLAGADM, TQM8260
1584 Define this variable to stop the system in case of a
1585 fatal error, so that you have to reset it manually.
1586 This is probably NOT a good idea for an embedded
1587 system where you want to system to reboot
1588 automatically as fast as possible, but it may be
1589 useful during development since you can try to debug
1590 the conditions that lead to the situation.
1592 CONFIG_NET_RETRY_COUNT
1594 This variable defines the number of retries for
1595 network operations like ARP, RARP, TFTP, or BOOTP
1596 before giving up the operation. If not defined, a
1597 default value of 5 is used.
1599 - Command Interpreter:
1600 CONFIG_AUTO_COMPLETE
1602 Enable auto completion of commands using TAB.
1604 Note that this feature has NOT been implemented yet
1605 for the "hush" shell.
1610 Define this variable to enable the "hush" shell (from
1611 Busybox) as command line interpreter, thus enabling
1612 powerful command line syntax like
1613 if...then...else...fi conditionals or `&&' and '||'
1614 constructs ("shell scripts").
1616 If undefined, you get the old, much simpler behaviour
1617 with a somewhat smaller memory footprint.
1622 This defines the secondary prompt string, which is
1623 printed when the command interpreter needs more input
1624 to complete a command. Usually "> ".
1628 In the current implementation, the local variables
1629 space and global environment variables space are
1630 separated. Local variables are those you define by
1631 simply typing `name=value'. To access a local
1632 variable later on, you have write `$name' or
1633 `${name}'; to execute the contents of a variable
1634 directly type `$name' at the command prompt.
1636 Global environment variables are those you use
1637 setenv/printenv to work with. To run a command stored
1638 in such a variable, you need to use the run command,
1639 and you must not use the '$' sign to access them.
1641 To store commands and special characters in a
1642 variable, please use double quotation marks
1643 surrounding the whole text of the variable, instead
1644 of the backslashes before semicolons and special
1647 - Commandline Editing and History:
1648 CONFIG_CMDLINE_EDITING
1650 Enable editiong and History functions for interactive
1651 commandline input operations
1653 - Default Environment:
1654 CONFIG_EXTRA_ENV_SETTINGS
1656 Define this to contain any number of null terminated
1657 strings (variable = value pairs) that will be part of
1658 the default environment compiled into the boot image.
1660 For example, place something like this in your
1661 board's config file:
1663 #define CONFIG_EXTRA_ENV_SETTINGS \
1667 Warning: This method is based on knowledge about the
1668 internal format how the environment is stored by the
1669 U-Boot code. This is NOT an official, exported
1670 interface! Although it is unlikely that this format
1671 will change soon, there is no guarantee either.
1672 You better know what you are doing here.
1674 Note: overly (ab)use of the default environment is
1675 discouraged. Make sure to check other ways to preset
1676 the environment like the autoscript function or the
1679 - DataFlash Support:
1680 CONFIG_HAS_DATAFLASH
1682 Defining this option enables DataFlash features and
1683 allows to read/write in Dataflash via the standard
1686 - SystemACE Support:
1689 Adding this option adds support for Xilinx SystemACE
1690 chips attached via some sort of local bus. The address
1691 of the chip must alsh be defined in the
1692 CFG_SYSTEMACE_BASE macro. For example:
1694 #define CONFIG_SYSTEMACE
1695 #define CFG_SYSTEMACE_BASE 0xf0000000
1697 When SystemACE support is added, the "ace" device type
1698 becomes available to the fat commands, i.e. fatls.
1700 - TFTP Fixed UDP Port:
1703 If this is defined, the environment variable tftpsrcp
1704 is used to supply the TFTP UDP source port value.
1705 If tftpsrcp isn't defined, the normal pseudo-random port
1706 number generator is used.
1708 Also, the environment variable tftpdstp is used to supply
1709 the TFTP UDP destination port value. If tftpdstp isn't
1710 defined, the normal port 69 is used.
1712 The purpose for tftpsrcp is to allow a TFTP server to
1713 blindly start the TFTP transfer using the pre-configured
1714 target IP address and UDP port. This has the effect of
1715 "punching through" the (Windows XP) firewall, allowing
1716 the remainder of the TFTP transfer to proceed normally.
1717 A better solution is to properly configure the firewall,
1718 but sometimes that is not allowed.
1720 - Show boot progress:
1721 CONFIG_SHOW_BOOT_PROGRESS
1723 Defining this option allows to add some board-
1724 specific code (calling a user-provided function
1725 "show_boot_progress(int)") that enables you to show
1726 the system's boot progress on some display (for
1727 example, some LED's) on your board. At the moment,
1728 the following checkpoints are implemented:
1731 1 common/cmd_bootm.c before attempting to boot an image
1732 -1 common/cmd_bootm.c Image header has bad magic number
1733 2 common/cmd_bootm.c Image header has correct magic number
1734 -2 common/cmd_bootm.c Image header has bad checksum
1735 3 common/cmd_bootm.c Image header has correct checksum
1736 -3 common/cmd_bootm.c Image data has bad checksum
1737 4 common/cmd_bootm.c Image data has correct checksum
1738 -4 common/cmd_bootm.c Image is for unsupported architecture
1739 5 common/cmd_bootm.c Architecture check OK
1740 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1741 6 common/cmd_bootm.c Image Type check OK
1742 -6 common/cmd_bootm.c gunzip uncompression error
1743 -7 common/cmd_bootm.c Unimplemented compression type
1744 7 common/cmd_bootm.c Uncompression OK
1745 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1746 8 common/cmd_bootm.c Image Type check OK
1747 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1748 9 common/cmd_bootm.c Start initial ramdisk verification
1749 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1750 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1751 10 common/cmd_bootm.c Ramdisk header is OK
1752 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1753 11 common/cmd_bootm.c Ramdisk data has correct checksum
1754 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1755 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1756 13 common/cmd_bootm.c Start multifile image verification
1757 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1758 15 common/cmd_bootm.c All preparation done, transferring control to OS
1760 -30 lib_ppc/board.c Fatal error, hang the system
1761 -31 post/post.c POST test failed, detected by post_output_backlog()
1762 -32 post/post.c POST test failed, detected by post_run_single()
1764 -1 common/cmd_doc.c Bad usage of "doc" command
1765 -1 common/cmd_doc.c No boot device
1766 -1 common/cmd_doc.c Unknown Chip ID on boot device
1767 -1 common/cmd_doc.c Read Error on boot device
1768 -1 common/cmd_doc.c Image header has bad magic number
1770 -1 common/cmd_ide.c Bad usage of "ide" command
1771 -1 common/cmd_ide.c No boot device
1772 -1 common/cmd_ide.c Unknown boot device
1773 -1 common/cmd_ide.c Unknown partition table
1774 -1 common/cmd_ide.c Invalid partition type
1775 -1 common/cmd_ide.c Read Error on boot device
1776 -1 common/cmd_ide.c Image header has bad magic number
1778 -1 common/cmd_nand.c Bad usage of "nand" command
1779 -1 common/cmd_nand.c No boot device
1780 -1 common/cmd_nand.c Unknown Chip ID on boot device
1781 -1 common/cmd_nand.c Read Error on boot device
1782 -1 common/cmd_nand.c Image header has bad magic number
1784 -1 common/env_common.c Environment has a bad CRC, using default
1790 [so far only for SMDK2400 and TRAB boards]
1792 - Modem support endable:
1793 CONFIG_MODEM_SUPPORT
1795 - RTS/CTS Flow control enable:
1798 - Modem debug support:
1799 CONFIG_MODEM_SUPPORT_DEBUG
1801 Enables debugging stuff (char screen[1024], dbg())
1802 for modem support. Useful only with BDI2000.
1804 - Interrupt support (PPC):
1806 There are common interrupt_init() and timer_interrupt()
1807 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1808 for cpu specific initialization. interrupt_init_cpu()
1809 should set decrementer_count to appropriate value. If
1810 cpu resets decrementer automatically after interrupt
1811 (ppc4xx) it should set decrementer_count to zero.
1812 timer_interrupt() calls timer_interrupt_cpu() for cpu
1813 specific handling. If board has watchdog / status_led
1814 / other_activity_monitor it works automatically from
1815 general timer_interrupt().
1819 In the target system modem support is enabled when a
1820 specific key (key combination) is pressed during
1821 power-on. Otherwise U-Boot will boot normally
1822 (autoboot). The key_pressed() fuction is called from
1823 board_init(). Currently key_pressed() is a dummy
1824 function, returning 1 and thus enabling modem
1827 If there are no modem init strings in the
1828 environment, U-Boot proceed to autoboot; the
1829 previous output (banner, info printfs) will be
1832 See also: doc/README.Modem
1835 Configuration Settings:
1836 -----------------------
1838 - CFG_LONGHELP: Defined when you want long help messages included;
1839 undefine this when you're short of memory.
1841 - CFG_PROMPT: This is what U-Boot prints on the console to
1842 prompt for user input.
1844 - CFG_CBSIZE: Buffer size for input from the Console
1846 - CFG_PBSIZE: Buffer size for Console output
1848 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1850 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1851 the application (usually a Linux kernel) when it is
1854 - CFG_BAUDRATE_TABLE:
1855 List of legal baudrate settings for this board.
1857 - CFG_CONSOLE_INFO_QUIET
1858 Suppress display of console information at boot.
1860 - CFG_CONSOLE_IS_IN_ENV
1861 If the board specific function
1862 extern int overwrite_console (void);
1863 returns 1, the stdin, stderr and stdout are switched to the
1864 serial port, else the settings in the environment are used.
1866 - CFG_CONSOLE_OVERWRITE_ROUTINE
1867 Enable the call to overwrite_console().
1869 - CFG_CONSOLE_ENV_OVERWRITE
1870 Enable overwrite of previous console environment settings.
1872 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1873 Begin and End addresses of the area used by the
1877 Enable an alternate, more extensive memory test.
1879 - CFG_MEMTEST_SCRATCH:
1880 Scratch address used by the alternate memory test
1881 You only need to set this if address zero isn't writeable
1883 - CFG_TFTP_LOADADDR:
1884 Default load address for network file downloads
1886 - CFG_LOADS_BAUD_CHANGE:
1887 Enable temporary baudrate change while serial download
1890 Physical start address of SDRAM. _Must_ be 0 here.
1893 Physical start address of Motherboard I/O (if using a
1897 Physical start address of Flash memory.
1900 Physical start address of boot monitor code (set by
1901 make config files to be same as the text base address
1902 (TEXT_BASE) used when linking) - same as
1903 CFG_FLASH_BASE when booting from flash.
1906 Size of memory reserved for monitor code, used to
1907 determine _at_compile_time_ (!) if the environment is
1908 embedded within the U-Boot image, or in a separate
1912 Size of DRAM reserved for malloc() use.
1915 Normally compressed uImages are limited to an
1916 uncompressed size of 8 MBytes. If this is not enough,
1917 you can define CFG_BOOTM_LEN in your board config file
1918 to adjust this setting to your needs.
1921 Maximum size of memory mapped by the startup code of
1922 the Linux kernel; all data that must be processed by
1923 the Linux kernel (bd_info, boot arguments, eventually
1924 initrd image) must be put below this limit.
1926 - CFG_MAX_FLASH_BANKS:
1927 Max number of Flash memory banks
1929 - CFG_MAX_FLASH_SECT:
1930 Max number of sectors on a Flash chip
1932 - CFG_FLASH_ERASE_TOUT:
1933 Timeout for Flash erase operations (in ms)
1935 - CFG_FLASH_WRITE_TOUT:
1936 Timeout for Flash write operations (in ms)
1938 - CFG_FLASH_LOCK_TOUT
1939 Timeout for Flash set sector lock bit operation (in ms)
1941 - CFG_FLASH_UNLOCK_TOUT
1942 Timeout for Flash clear lock bits operation (in ms)
1944 - CFG_FLASH_PROTECTION
1945 If defined, hardware flash sectors protection is used
1946 instead of U-Boot software protection.
1948 - CFG_DIRECT_FLASH_TFTP:
1950 Enable TFTP transfers directly to flash memory;
1951 without this option such a download has to be
1952 performed in two steps: (1) download to RAM, and (2)
1953 copy from RAM to flash.
1955 The two-step approach is usually more reliable, since
1956 you can check if the download worked before you erase
1957 the flash, but in some situations (when sytem RAM is
1958 too limited to allow for a tempory copy of the
1959 downloaded image) this option may be very useful.
1962 Define if the flash driver uses extra elements in the
1963 common flash structure for storing flash geometry.
1965 - CFG_FLASH_CFI_DRIVER
1966 This option also enables the building of the cfi_flash driver
1967 in the drivers directory
1969 - CFG_FLASH_QUIET_TEST
1970 If this option is defined, the common CFI flash doesn't
1971 print it's warning upon not recognized FLASH banks. This
1972 is useful, if some of the configured banks are only
1973 optionally available.
1975 - CFG_RX_ETH_BUFFER:
1976 Defines the number of ethernet receive buffers. On some
1977 ethernet controllers it is recommended to set this value
1978 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1979 buffers can be full shortly after enabling the interface
1980 on high ethernet traffic.
1981 Defaults to 4 if not defined.
1983 The following definitions that deal with the placement and management
1984 of environment data (variable area); in general, we support the
1985 following configurations:
1987 - CFG_ENV_IS_IN_FLASH:
1989 Define this if the environment is in flash memory.
1991 a) The environment occupies one whole flash sector, which is
1992 "embedded" in the text segment with the U-Boot code. This
1993 happens usually with "bottom boot sector" or "top boot
1994 sector" type flash chips, which have several smaller
1995 sectors at the start or the end. For instance, such a
1996 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1997 such a case you would place the environment in one of the
1998 4 kB sectors - with U-Boot code before and after it. With
1999 "top boot sector" type flash chips, you would put the
2000 environment in one of the last sectors, leaving a gap
2001 between U-Boot and the environment.
2005 Offset of environment data (variable area) to the
2006 beginning of flash memory; for instance, with bottom boot
2007 type flash chips the second sector can be used: the offset
2008 for this sector is given here.
2010 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2014 This is just another way to specify the start address of
2015 the flash sector containing the environment (instead of
2018 - CFG_ENV_SECT_SIZE:
2020 Size of the sector containing the environment.
2023 b) Sometimes flash chips have few, equal sized, BIG sectors.
2024 In such a case you don't want to spend a whole sector for
2029 If you use this in combination with CFG_ENV_IS_IN_FLASH
2030 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2031 of this flash sector for the environment. This saves
2032 memory for the RAM copy of the environment.
2034 It may also save flash memory if you decide to use this
2035 when your environment is "embedded" within U-Boot code,
2036 since then the remainder of the flash sector could be used
2037 for U-Boot code. It should be pointed out that this is
2038 STRONGLY DISCOURAGED from a robustness point of view:
2039 updating the environment in flash makes it always
2040 necessary to erase the WHOLE sector. If something goes
2041 wrong before the contents has been restored from a copy in
2042 RAM, your target system will be dead.
2044 - CFG_ENV_ADDR_REDUND
2047 These settings describe a second storage area used to hold
2048 a redundand copy of the environment data, so that there is
2049 a valid backup copy in case there is a power failure during
2050 a "saveenv" operation.
2052 BE CAREFUL! Any changes to the flash layout, and some changes to the
2053 source code will make it necessary to adapt <board>/u-boot.lds*
2057 - CFG_ENV_IS_IN_NVRAM:
2059 Define this if you have some non-volatile memory device
2060 (NVRAM, battery buffered SRAM) which you want to use for the
2066 These two #defines are used to determin the memory area you
2067 want to use for environment. It is assumed that this memory
2068 can just be read and written to, without any special
2071 BE CAREFUL! The first access to the environment happens quite early
2072 in U-Boot initalization (when we try to get the setting of for the
2073 console baudrate). You *MUST* have mappend your NVRAM area then, or
2076 Please note that even with NVRAM we still use a copy of the
2077 environment in RAM: we could work on NVRAM directly, but we want to
2078 keep settings there always unmodified except somebody uses "saveenv"
2079 to save the current settings.
2082 - CFG_ENV_IS_IN_EEPROM:
2084 Use this if you have an EEPROM or similar serial access
2085 device and a driver for it.
2090 These two #defines specify the offset and size of the
2091 environment area within the total memory of your EEPROM.
2093 - CFG_I2C_EEPROM_ADDR:
2094 If defined, specified the chip address of the EEPROM device.
2095 The default address is zero.
2097 - CFG_EEPROM_PAGE_WRITE_BITS:
2098 If defined, the number of bits used to address bytes in a
2099 single page in the EEPROM device. A 64 byte page, for example
2100 would require six bits.
2102 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2103 If defined, the number of milliseconds to delay between
2104 page writes. The default is zero milliseconds.
2106 - CFG_I2C_EEPROM_ADDR_LEN:
2107 The length in bytes of the EEPROM memory array address. Note
2108 that this is NOT the chip address length!
2110 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2111 EEPROM chips that implement "address overflow" are ones
2112 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2113 address and the extra bits end up in the "chip address" bit
2114 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2117 Note that we consider the length of the address field to
2118 still be one byte because the extra address bits are hidden
2119 in the chip address.
2122 The size in bytes of the EEPROM device.
2125 - CFG_ENV_IS_IN_DATAFLASH:
2127 Define this if you have a DataFlash memory device which you
2128 want to use for the environment.
2134 These three #defines specify the offset and size of the
2135 environment area within the total memory of your DataFlash placed
2136 at the specified address.
2138 - CFG_ENV_IS_IN_NAND:
2140 Define this if you have a NAND device which you want to use
2141 for the environment.
2146 These two #defines specify the offset and size of the environment
2147 area within the first NAND device.
2149 - CFG_ENV_OFFSET_REDUND
2151 This setting describes a second storage area of CFG_ENV_SIZE
2152 size used to hold a redundant copy of the environment data,
2153 so that there is a valid backup copy in case there is a
2154 power failure during a "saveenv" operation.
2156 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2157 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2158 the NAND devices block size.
2160 - CFG_SPI_INIT_OFFSET
2162 Defines offset to the initial SPI buffer area in DPRAM. The
2163 area is used at an early stage (ROM part) if the environment
2164 is configured to reside in the SPI EEPROM: We need a 520 byte
2165 scratch DPRAM area. It is used between the two initialization
2166 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2167 to be a good choice since it makes it far enough from the
2168 start of the data area as well as from the stack pointer.
2170 Please note that the environment is read-only as long as the monitor
2171 has been relocated to RAM and a RAM copy of the environment has been
2172 created; also, when using EEPROM you will have to use getenv_r()
2173 until then to read environment variables.
2175 The environment is protected by a CRC32 checksum. Before the monitor
2176 is relocated into RAM, as a result of a bad CRC you will be working
2177 with the compiled-in default environment - *silently*!!! [This is
2178 necessary, because the first environment variable we need is the
2179 "baudrate" setting for the console - if we have a bad CRC, we don't
2180 have any device yet where we could complain.]
2182 Note: once the monitor has been relocated, then it will complain if
2183 the default environment is used; a new CRC is computed as soon as you
2184 use the "saveenv" command to store a valid environment.
2186 - CFG_FAULT_ECHO_LINK_DOWN:
2187 Echo the inverted Ethernet link state to the fault LED.
2189 Note: If this option is active, then CFG_FAULT_MII_ADDR
2190 also needs to be defined.
2192 - CFG_FAULT_MII_ADDR:
2193 MII address of the PHY to check for the Ethernet link state.
2195 - CFG_64BIT_VSPRINTF:
2196 Makes vsprintf (and all *printf functions) support printing
2197 of 64bit values by using the L quantifier
2199 - CFG_64BIT_STRTOUL:
2200 Adds simple_strtoull that returns a 64bit value
2202 Low Level (hardware related) configuration options:
2203 ---------------------------------------------------
2205 - CFG_CACHELINE_SIZE:
2206 Cache Line Size of the CPU.
2209 Default address of the IMMR after system reset.
2211 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2212 and RPXsuper) to be able to adjust the position of
2213 the IMMR register after a reset.
2215 - Floppy Disk Support:
2216 CFG_FDC_DRIVE_NUMBER
2218 the default drive number (default value 0)
2222 defines the spacing between fdc chipset registers
2227 defines the offset of register from address. It
2228 depends on which part of the data bus is connected to
2229 the fdc chipset. (default value 0)
2231 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2232 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2235 if CFG_FDC_HW_INIT is defined, then the function
2236 fdc_hw_init() is called at the beginning of the FDC
2237 setup. fdc_hw_init() must be provided by the board
2238 source code. It is used to make hardware dependant
2241 - CFG_IMMR: Physical address of the Internal Memory.
2242 DO NOT CHANGE unless you know exactly what you're
2243 doing! (11-4) [MPC8xx/82xx systems only]
2245 - CFG_INIT_RAM_ADDR:
2247 Start address of memory area that can be used for
2248 initial data and stack; please note that this must be
2249 writable memory that is working WITHOUT special
2250 initialization, i. e. you CANNOT use normal RAM which
2251 will become available only after programming the
2252 memory controller and running certain initialization
2255 U-Boot uses the following memory types:
2256 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2257 - MPC824X: data cache
2258 - PPC4xx: data cache
2260 - CFG_GBL_DATA_OFFSET:
2262 Offset of the initial data structure in the memory
2263 area defined by CFG_INIT_RAM_ADDR. Usually
2264 CFG_GBL_DATA_OFFSET is chosen such that the initial
2265 data is located at the end of the available space
2266 (sometimes written as (CFG_INIT_RAM_END -
2267 CFG_INIT_DATA_SIZE), and the initial stack is just
2268 below that area (growing from (CFG_INIT_RAM_ADDR +
2269 CFG_GBL_DATA_OFFSET) downward.
2272 On the MPC824X (or other systems that use the data
2273 cache for initial memory) the address chosen for
2274 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2275 point to an otherwise UNUSED address space between
2276 the top of RAM and the start of the PCI space.
2278 - CFG_SIUMCR: SIU Module Configuration (11-6)
2280 - CFG_SYPCR: System Protection Control (11-9)
2282 - CFG_TBSCR: Time Base Status and Control (11-26)
2284 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2286 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2288 - CFG_SCCR: System Clock and reset Control Register (15-27)
2290 - CFG_OR_TIMING_SDRAM:
2294 periodic timer for refresh
2296 - CFG_DER: Debug Event Register (37-47)
2298 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2299 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2300 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2302 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2304 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2305 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2306 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2307 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2309 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2310 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2311 Machine Mode Register and Memory Periodic Timer
2312 Prescaler definitions (SDRAM timing)
2314 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2315 enable I2C microcode relocation patch (MPC8xx);
2316 define relocation offset in DPRAM [DSP2]
2318 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2319 enable SPI microcode relocation patch (MPC8xx);
2320 define relocation offset in DPRAM [SCC4]
2323 Use OSCM clock mode on MBX8xx board. Be careful,
2324 wrong setting might damage your board. Read
2325 doc/README.MBX before setting this variable!
2327 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2328 Offset of the bootmode word in DPRAM used by post
2329 (Power On Self Tests). This definition overrides
2330 #define'd default value in commproc.h resp.
2333 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2334 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2335 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2336 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2337 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2338 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2339 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2340 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2341 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2344 Get DDR timing information from an I2C EEPROM. Common with pluggable
2345 memory modules such as SODIMMs
2347 I2C address of the SPD EEPROM
2350 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2351 Note that the value must resolve to something your driver can deal with.
2353 - CFG_83XX_DDR_USES_CS0
2354 Only for 83xx systems. If specified, then DDR should be configured
2355 using CS0 and CS1 instead of CS2 and CS3.
2357 - CFG_83XX_DDR_USES_CS0
2358 Only for 83xx systems. If specified, then DDR should be configured
2359 using CS0 and CS1 instead of CS2 and CS3.
2361 - CONFIG_ETHER_ON_FEC[12]
2362 Define to enable FEC[12] on a 8xx series processor.
2364 - CONFIG_FEC[12]_PHY
2365 Define to the hardcoded PHY address which corresponds
2366 to the given FEC; i. e.
2367 #define CONFIG_FEC1_PHY 4
2368 means that the PHY with address 4 is connected to FEC1
2370 When set to -1, means to probe for first available.
2372 - CONFIG_FEC[12]_PHY_NORXERR
2373 The PHY does not have a RXERR line (RMII only).
2374 (so program the FEC to ignore it).
2377 Enable RMII mode for all FECs.
2378 Note that this is a global option, we can't
2379 have one FEC in standard MII mode and another in RMII mode.
2381 - CONFIG_CRC32_VERIFY
2382 Add a verify option to the crc32 command.
2385 => crc32 -v <address> <count> <crc32>
2387 Where address/count indicate a memory area
2388 and crc32 is the correct crc32 which the
2392 Add the "loopw" memory command. This only takes effect if
2393 the memory commands are activated globally (CFG_CMD_MEM).
2396 Add the "mdc" and "mwc" memory commands. These are cyclic
2401 This command will print 4 bytes (10,11,12,13) each 500 ms.
2403 => mwc.l 100 12345678 10
2404 This command will write 12345678 to address 100 all 10 ms.
2406 This only takes effect if the memory commands are activated
2407 globally (CFG_CMD_MEM).
2409 - CONFIG_SKIP_LOWLEVEL_INIT
2410 - CONFIG_SKIP_RELOCATE_UBOOT
2412 [ARM only] If these variables are defined, then
2413 certain low level initializations (like setting up
2414 the memory controller) are omitted and/or U-Boot does
2415 not relocate itself into RAM.
2416 Normally these variables MUST NOT be defined. The
2417 only exception is when U-Boot is loaded (to RAM) by
2418 some other boot loader or by a debugger which
2419 performs these intializations itself.
2422 Building the Software:
2423 ======================
2425 Building U-Boot has been tested in native PPC environments (on a
2426 PowerBook G3 running LinuxPPC 2000) and in cross environments
2427 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2430 If you are not using a native PPC environment, it is assumed that you
2431 have the GNU cross compiling tools available in your path and named
2432 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2433 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2434 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2437 CROSS_COMPILE = ppc_4xx-
2440 U-Boot is intended to be simple to build. After installing the
2441 sources you must configure U-Boot for one specific board type. This
2446 where "NAME_config" is the name of one of the existing
2447 configurations; the following names are supported:
2449 ADCIOP_config FPS860L_config omap730p2_config
2450 ADS860_config GEN860T_config pcu_e_config
2452 AR405_config GENIETV_config PIP405_config
2453 at91rm9200dk_config GTH_config QS823_config
2454 CANBT_config hermes_config QS850_config
2455 cmi_mpc5xx_config hymod_config QS860T_config
2456 cogent_common_config IP860_config RPXlite_config
2457 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2458 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2459 CPCI405_config JSE_config rsdproto_config
2460 CPCIISER4_config LANTEC_config Sandpoint8240_config
2461 csb272_config lwmon_config sbc8260_config
2462 CU824_config MBX860T_config sbc8560_33_config
2463 DUET_ADS_config MBX_config sbc8560_66_config
2464 EBONY_config mpc7448hpc2_config SM850_config
2465 ELPT860_config MPC8260ADS_config SPD823TS_config
2466 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2467 ETX094_config MPC8540EVAL_config SXNI855T_config
2468 FADS823_config NMPC8560ADS_config TQM823L_config
2469 FADS850SAR_config NETVIA_config TQM850L_config
2470 FADS860T_config omap1510inn_config TQM855L_config
2471 FPS850L_config omap1610h2_config TQM860L_config
2472 omap1610inn_config walnut_config
2473 omap5912osk_config Yukon8220_config
2474 omap2420h4_config ZPC1900_config
2476 Note: for some board special configuration names may exist; check if
2477 additional information is available from the board vendor; for
2478 instance, the TQM823L systems are available without (standard)
2479 or with LCD support. You can select such additional "features"
2480 when chosing the configuration, i. e.
2483 - will configure for a plain TQM823L, i. e. no LCD support
2485 make TQM823L_LCD_config
2486 - will configure for a TQM823L with U-Boot console on LCD
2491 Finally, type "make all", and you should get some working U-Boot
2492 images ready for download to / installation on your system:
2494 - "u-boot.bin" is a raw binary image
2495 - "u-boot" is an image in ELF binary format
2496 - "u-boot.srec" is in Motorola S-Record format
2498 By default the build is performed locally and the objects are saved
2499 in the source directory. One of the two methods can be used to change
2500 this behavior and build U-Boot to some external directory:
2502 1. Add O= to the make command line invocations:
2504 make O=/tmp/build distclean
2505 make O=/tmp/build NAME_config
2506 make O=/tmp/build all
2508 2. Set environment variable BUILD_DIR to point to the desired location:
2510 export BUILD_DIR=/tmp/build
2515 Note that the command line "O=" setting overrides the BUILD_DIR environment
2519 Please be aware that the Makefiles assume you are using GNU make, so
2520 for instance on NetBSD you might need to use "gmake" instead of
2524 If the system board that you have is not listed, then you will need
2525 to port U-Boot to your hardware platform. To do this, follow these
2528 1. Add a new configuration option for your board to the toplevel
2529 "Makefile" and to the "MAKEALL" script, using the existing
2530 entries as examples. Note that here and at many other places
2531 boards and other names are listed in alphabetical sort order. Please
2533 2. Create a new directory to hold your board specific code. Add any
2534 files you need. In your board directory, you will need at least
2535 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2536 3. Create a new configuration file "include/configs/<board>.h" for
2538 3. If you're porting U-Boot to a new CPU, then also create a new
2539 directory to hold your CPU specific code. Add any files you need.
2540 4. Run "make <board>_config" with your new name.
2541 5. Type "make", and you should get a working "u-boot.srec" file
2542 to be installed on your target system.
2543 6. Debug and solve any problems that might arise.
2544 [Of course, this last step is much harder than it sounds.]
2547 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2548 ==============================================================
2550 If you have modified U-Boot sources (for instance added a new board
2551 or support for new devices, a new CPU, etc.) you are expected to
2552 provide feedback to the other developers. The feedback normally takes
2553 the form of a "patch", i. e. a context diff against a certain (latest
2554 official or latest in CVS) version of U-Boot sources.
2556 But before you submit such a patch, please verify that your modifi-
2557 cation did not break existing code. At least make sure that *ALL* of
2558 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2559 just run the "MAKEALL" script, which will configure and build U-Boot
2560 for ALL supported system. Be warned, this will take a while. You can
2561 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2562 environment variable to the script, i. e. to use the cross tools from
2563 MontaVista's Hard Hat Linux you can type
2565 CROSS_COMPILE=ppc_8xx- MAKEALL
2567 or to build on a native PowerPC system you can type
2569 CROSS_COMPILE=' ' MAKEALL
2571 When using the MAKEALL script, the default behaviour is to build U-Boot
2572 in the source directory. This location can be changed by setting the
2573 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2574 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2575 <source dir>/LOG directory. This default location can be changed by
2576 setting the MAKEALL_LOGDIR environment variable. For example:
2578 export BUILD_DIR=/tmp/build
2579 export MAKEALL_LOGDIR=/tmp/log
2580 CROSS_COMPILE=ppc_8xx- MAKEALL
2582 With the above settings build objects are saved in the /tmp/build, log
2583 files are saved in the /tmp/log and the source tree remains clean during
2584 the whole build process.
2587 See also "U-Boot Porting Guide" below.
2590 Monitor Commands - Overview:
2591 ============================
2593 go - start application at address 'addr'
2594 run - run commands in an environment variable
2595 bootm - boot application image from memory
2596 bootp - boot image via network using BootP/TFTP protocol
2597 tftpboot- boot image via network using TFTP protocol
2598 and env variables "ipaddr" and "serverip"
2599 (and eventually "gatewayip")
2600 rarpboot- boot image via network using RARP/TFTP protocol
2601 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2602 loads - load S-Record file over serial line
2603 loadb - load binary file over serial line (kermit mode)
2605 mm - memory modify (auto-incrementing)
2606 nm - memory modify (constant address)
2607 mw - memory write (fill)
2609 cmp - memory compare
2610 crc32 - checksum calculation
2611 imd - i2c memory display
2612 imm - i2c memory modify (auto-incrementing)
2613 inm - i2c memory modify (constant address)
2614 imw - i2c memory write (fill)
2615 icrc32 - i2c checksum calculation
2616 iprobe - probe to discover valid I2C chip addresses
2617 iloop - infinite loop on address range
2618 isdram - print SDRAM configuration information
2619 sspi - SPI utility commands
2620 base - print or set address offset
2621 printenv- print environment variables
2622 setenv - set environment variables
2623 saveenv - save environment variables to persistent storage
2624 protect - enable or disable FLASH write protection
2625 erase - erase FLASH memory
2626 flinfo - print FLASH memory information
2627 bdinfo - print Board Info structure
2628 iminfo - print header information for application image
2629 coninfo - print console devices and informations
2630 ide - IDE sub-system
2631 loop - infinite loop on address range
2632 loopw - infinite write loop on address range
2633 mtest - simple RAM test
2634 icache - enable or disable instruction cache
2635 dcache - enable or disable data cache
2636 reset - Perform RESET of the CPU
2637 echo - echo args to console
2638 version - print monitor version
2639 help - print online help
2640 ? - alias for 'help'
2643 Monitor Commands - Detailed Description:
2644 ========================================
2648 For now: just type "help <command>".
2651 Environment Variables:
2652 ======================
2654 U-Boot supports user configuration using Environment Variables which
2655 can be made persistent by saving to Flash memory.
2657 Environment Variables are set using "setenv", printed using
2658 "printenv", and saved to Flash using "saveenv". Using "setenv"
2659 without a value can be used to delete a variable from the
2660 environment. As long as you don't save the environment you are
2661 working with an in-memory copy. In case the Flash area containing the
2662 environment is erased by accident, a default environment is provided.
2664 Some configuration options can be set using Environment Variables:
2666 baudrate - see CONFIG_BAUDRATE
2668 bootdelay - see CONFIG_BOOTDELAY
2670 bootcmd - see CONFIG_BOOTCOMMAND
2672 bootargs - Boot arguments when booting an RTOS image
2674 bootfile - Name of the image to load with TFTP
2676 autoload - if set to "no" (any string beginning with 'n'),
2677 "bootp" will just load perform a lookup of the
2678 configuration from the BOOTP server, but not try to
2679 load any image using TFTP
2681 autostart - if set to "yes", an image loaded using the "bootp",
2682 "rarpboot", "tftpboot" or "diskboot" commands will
2683 be automatically started (by internally calling
2686 If set to "no", a standalone image passed to the
2687 "bootm" command will be copied to the load address
2688 (and eventually uncompressed), but NOT be started.
2689 This can be used to load and uncompress arbitrary
2692 i2cfast - (PPC405GP|PPC405EP only)
2693 if set to 'y' configures Linux I2C driver for fast
2694 mode (400kHZ). This environment variable is used in
2695 initialization code. So, for changes to be effective
2696 it must be saved and board must be reset.
2698 initrd_high - restrict positioning of initrd images:
2699 If this variable is not set, initrd images will be
2700 copied to the highest possible address in RAM; this
2701 is usually what you want since it allows for
2702 maximum initrd size. If for some reason you want to
2703 make sure that the initrd image is loaded below the
2704 CFG_BOOTMAPSZ limit, you can set this environment
2705 variable to a value of "no" or "off" or "0".
2706 Alternatively, you can set it to a maximum upper
2707 address to use (U-Boot will still check that it
2708 does not overwrite the U-Boot stack and data).
2710 For instance, when you have a system with 16 MB
2711 RAM, and want to reserve 4 MB from use by Linux,
2712 you can do this by adding "mem=12M" to the value of
2713 the "bootargs" variable. However, now you must make
2714 sure that the initrd image is placed in the first
2715 12 MB as well - this can be done with
2717 setenv initrd_high 00c00000
2719 If you set initrd_high to 0xFFFFFFFF, this is an
2720 indication to U-Boot that all addresses are legal
2721 for the Linux kernel, including addresses in flash
2722 memory. In this case U-Boot will NOT COPY the
2723 ramdisk at all. This may be useful to reduce the
2724 boot time on your system, but requires that this
2725 feature is supported by your Linux kernel.
2727 ipaddr - IP address; needed for tftpboot command
2729 loadaddr - Default load address for commands like "bootp",
2730 "rarpboot", "tftpboot", "loadb" or "diskboot"
2732 loads_echo - see CONFIG_LOADS_ECHO
2734 serverip - TFTP server IP address; needed for tftpboot command
2736 bootretry - see CONFIG_BOOT_RETRY_TIME
2738 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2740 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2742 ethprime - When CONFIG_NET_MULTI is enabled controls which
2743 interface is used first.
2745 ethact - When CONFIG_NET_MULTI is enabled controls which
2746 interface is currently active. For example you
2747 can do the following
2749 => setenv ethact FEC ETHERNET
2750 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2751 => setenv ethact SCC ETHERNET
2752 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2754 netretry - When set to "no" each network operation will
2755 either succeed or fail without retrying.
2756 When set to "once" the network operation will
2757 fail when all the available network interfaces
2758 are tried once without success.
2759 Useful on scripts which control the retry operation
2762 tftpsrcport - If this is set, the value is used for TFTP's
2765 tftpdstport - If this is set, the value is used for TFTP's UDP
2766 destination port instead of the Well Know Port 69.
2768 vlan - When set to a value < 4095 the traffic over
2769 ethernet is encapsulated/received over 802.1q
2772 The following environment variables may be used and automatically
2773 updated by the network boot commands ("bootp" and "rarpboot"),
2774 depending the information provided by your boot server:
2776 bootfile - see above
2777 dnsip - IP address of your Domain Name Server
2778 dnsip2 - IP address of your secondary Domain Name Server
2779 gatewayip - IP address of the Gateway (Router) to use
2780 hostname - Target hostname
2782 netmask - Subnet Mask
2783 rootpath - Pathname of the root filesystem on the NFS server
2784 serverip - see above
2787 There are two special Environment Variables:
2789 serial# - contains hardware identification information such
2790 as type string and/or serial number
2791 ethaddr - Ethernet address
2793 These variables can be set only once (usually during manufacturing of
2794 the board). U-Boot refuses to delete or overwrite these variables
2795 once they have been set once.
2798 Further special Environment Variables:
2800 ver - Contains the U-Boot version string as printed
2801 with the "version" command. This variable is
2802 readonly (see CONFIG_VERSION_VARIABLE).
2805 Please note that changes to some configuration parameters may take
2806 only effect after the next boot (yes, that's just like Windoze :-).
2809 Command Line Parsing:
2810 =====================
2812 There are two different command line parsers available with U-Boot:
2813 the old "simple" one, and the much more powerful "hush" shell:
2815 Old, simple command line parser:
2816 --------------------------------
2818 - supports environment variables (through setenv / saveenv commands)
2819 - several commands on one line, separated by ';'
2820 - variable substitution using "... ${name} ..." syntax
2821 - special characters ('$', ';') can be escaped by prefixing with '\',
2823 setenv bootcmd bootm \${address}
2824 - You can also escape text by enclosing in single apostrophes, for example:
2825 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2830 - similar to Bourne shell, with control structures like
2831 if...then...else...fi, for...do...done; while...do...done,
2832 until...do...done, ...
2833 - supports environment ("global") variables (through setenv / saveenv
2834 commands) and local shell variables (through standard shell syntax
2835 "name=value"); only environment variables can be used with "run"
2841 (1) If a command line (or an environment variable executed by a "run"
2842 command) contains several commands separated by semicolon, and
2843 one of these commands fails, then the remaining commands will be
2846 (2) If you execute several variables with one call to run (i. e.
2847 calling run with a list af variables as arguments), any failing
2848 command will cause "run" to terminate, i. e. the remaining
2849 variables are not executed.
2851 Note for Redundant Ethernet Interfaces:
2852 =======================================
2854 Some boards come with redundant ethernet interfaces; U-Boot supports
2855 such configurations and is capable of automatic selection of a
2856 "working" interface when needed. MAC assignment works as follows:
2858 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2859 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2860 "eth1addr" (=>eth1), "eth2addr", ...
2862 If the network interface stores some valid MAC address (for instance
2863 in SROM), this is used as default address if there is NO correspon-
2864 ding setting in the environment; if the corresponding environment
2865 variable is set, this overrides the settings in the card; that means:
2867 o If the SROM has a valid MAC address, and there is no address in the
2868 environment, the SROM's address is used.
2870 o If there is no valid address in the SROM, and a definition in the
2871 environment exists, then the value from the environment variable is
2874 o If both the SROM and the environment contain a MAC address, and
2875 both addresses are the same, this MAC address is used.
2877 o If both the SROM and the environment contain a MAC address, and the
2878 addresses differ, the value from the environment is used and a
2881 o If neither SROM nor the environment contain a MAC address, an error
2888 The "boot" commands of this monitor operate on "image" files which
2889 can be basicly anything, preceeded by a special header; see the
2890 definitions in include/image.h for details; basicly, the header
2891 defines the following image properties:
2893 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2894 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2895 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2896 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2897 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2898 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2899 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2900 * Compression Type (uncompressed, gzip, bzip2)
2906 The header is marked by a special Magic Number, and both the header
2907 and the data portions of the image are secured against corruption by
2914 Although U-Boot should support any OS or standalone application
2915 easily, the main focus has always been on Linux during the design of
2918 U-Boot includes many features that so far have been part of some
2919 special "boot loader" code within the Linux kernel. Also, any
2920 "initrd" images to be used are no longer part of one big Linux image;
2921 instead, kernel and "initrd" are separate images. This implementation
2922 serves several purposes:
2924 - the same features can be used for other OS or standalone
2925 applications (for instance: using compressed images to reduce the
2926 Flash memory footprint)
2928 - it becomes much easier to port new Linux kernel versions because
2929 lots of low-level, hardware dependent stuff are done by U-Boot
2931 - the same Linux kernel image can now be used with different "initrd"
2932 images; of course this also means that different kernel images can
2933 be run with the same "initrd". This makes testing easier (you don't
2934 have to build a new "zImage.initrd" Linux image when you just
2935 change a file in your "initrd"). Also, a field-upgrade of the
2936 software is easier now.
2942 Porting Linux to U-Boot based systems:
2943 ---------------------------------------
2945 U-Boot cannot save you from doing all the necessary modifications to
2946 configure the Linux device drivers for use with your target hardware
2947 (no, we don't intend to provide a full virtual machine interface to
2950 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2952 Just make sure your machine specific header file (for instance
2953 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2954 Information structure as we define in include/u-boot.h, and make
2955 sure that your definition of IMAP_ADDR uses the same value as your
2956 U-Boot configuration in CFG_IMMR.
2959 Configuring the Linux kernel:
2960 -----------------------------
2962 No specific requirements for U-Boot. Make sure you have some root
2963 device (initial ramdisk, NFS) for your target system.
2966 Building a Linux Image:
2967 -----------------------
2969 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2970 not used. If you use recent kernel source, a new build target
2971 "uImage" will exist which automatically builds an image usable by
2972 U-Boot. Most older kernels also have support for a "pImage" target,
2973 which was introduced for our predecessor project PPCBoot and uses a
2974 100% compatible format.
2983 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2984 encapsulate a compressed Linux kernel image with header information,
2985 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2987 * build a standard "vmlinux" kernel image (in ELF binary format):
2989 * convert the kernel into a raw binary image:
2991 ${CROSS_COMPILE}-objcopy -O binary \
2992 -R .note -R .comment \
2993 -S vmlinux linux.bin
2995 * compress the binary image:
2999 * package compressed binary image for U-Boot:
3001 mkimage -A ppc -O linux -T kernel -C gzip \
3002 -a 0 -e 0 -n "Linux Kernel Image" \
3003 -d linux.bin.gz uImage
3006 The "mkimage" tool can also be used to create ramdisk images for use
3007 with U-Boot, either separated from the Linux kernel image, or
3008 combined into one file. "mkimage" encapsulates the images with a 64
3009 byte header containing information about target architecture,
3010 operating system, image type, compression method, entry points, time
3011 stamp, CRC32 checksums, etc.
3013 "mkimage" can be called in two ways: to verify existing images and
3014 print the header information, or to build new images.
3016 In the first form (with "-l" option) mkimage lists the information
3017 contained in the header of an existing U-Boot image; this includes
3018 checksum verification:
3020 tools/mkimage -l image
3021 -l ==> list image header information
3023 The second form (with "-d" option) is used to build a U-Boot image
3024 from a "data file" which is used as image payload:
3026 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3027 -n name -d data_file image
3028 -A ==> set architecture to 'arch'
3029 -O ==> set operating system to 'os'
3030 -T ==> set image type to 'type'
3031 -C ==> set compression type 'comp'
3032 -a ==> set load address to 'addr' (hex)
3033 -e ==> set entry point to 'ep' (hex)
3034 -n ==> set image name to 'name'
3035 -d ==> use image data from 'datafile'
3037 Right now, all Linux kernels for PowerPC systems use the same load
3038 address (0x00000000), but the entry point address depends on the
3041 - 2.2.x kernels have the entry point at 0x0000000C,
3042 - 2.3.x and later kernels have the entry point at 0x00000000.
3044 So a typical call to build a U-Boot image would read:
3046 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3047 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3048 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3049 > examples/uImage.TQM850L
3050 Image Name: 2.4.4 kernel for TQM850L
3051 Created: Wed Jul 19 02:34:59 2000
3052 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3053 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3054 Load Address: 0x00000000
3055 Entry Point: 0x00000000
3057 To verify the contents of the image (or check for corruption):
3059 -> tools/mkimage -l examples/uImage.TQM850L
3060 Image Name: 2.4.4 kernel for TQM850L
3061 Created: Wed Jul 19 02:34:59 2000
3062 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3063 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3064 Load Address: 0x00000000
3065 Entry Point: 0x00000000
3067 NOTE: for embedded systems where boot time is critical you can trade
3068 speed for memory and install an UNCOMPRESSED image instead: this
3069 needs more space in Flash, but boots much faster since it does not
3070 need to be uncompressed:
3072 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3073 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3074 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3075 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3076 > examples/uImage.TQM850L-uncompressed
3077 Image Name: 2.4.4 kernel for TQM850L
3078 Created: Wed Jul 19 02:34:59 2000
3079 Image Type: PowerPC Linux Kernel Image (uncompressed)
3080 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3081 Load Address: 0x00000000
3082 Entry Point: 0x00000000
3085 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3086 when your kernel is intended to use an initial ramdisk:
3088 -> tools/mkimage -n 'Simple Ramdisk Image' \
3089 > -A ppc -O linux -T ramdisk -C gzip \
3090 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3091 Image Name: Simple Ramdisk Image
3092 Created: Wed Jan 12 14:01:50 2000
3093 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3094 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3095 Load Address: 0x00000000
3096 Entry Point: 0x00000000
3099 Installing a Linux Image:
3100 -------------------------
3102 To downloading a U-Boot image over the serial (console) interface,
3103 you must convert the image to S-Record format:
3105 objcopy -I binary -O srec examples/image examples/image.srec
3107 The 'objcopy' does not understand the information in the U-Boot
3108 image header, so the resulting S-Record file will be relative to
3109 address 0x00000000. To load it to a given address, you need to
3110 specify the target address as 'offset' parameter with the 'loads'
3113 Example: install the image to address 0x40100000 (which on the
3114 TQM8xxL is in the first Flash bank):
3116 => erase 40100000 401FFFFF
3122 ## Ready for S-Record download ...
3123 ~>examples/image.srec
3124 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3126 15989 15990 15991 15992
3127 [file transfer complete]
3129 ## Start Addr = 0x00000000
3132 You can check the success of the download using the 'iminfo' command;
3133 this includes a checksum verification so you can be sure no data
3134 corruption happened:
3138 ## Checking Image at 40100000 ...
3139 Image Name: 2.2.13 for initrd on TQM850L
3140 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3141 Data Size: 335725 Bytes = 327 kB = 0 MB
3142 Load Address: 00000000
3143 Entry Point: 0000000c
3144 Verifying Checksum ... OK
3150 The "bootm" command is used to boot an application that is stored in
3151 memory (RAM or Flash). In case of a Linux kernel image, the contents
3152 of the "bootargs" environment variable is passed to the kernel as
3153 parameters. You can check and modify this variable using the
3154 "printenv" and "setenv" commands:
3157 => printenv bootargs
3158 bootargs=root=/dev/ram
3160 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3162 => printenv bootargs
3163 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3166 ## Booting Linux kernel at 40020000 ...
3167 Image Name: 2.2.13 for NFS on TQM850L
3168 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3169 Data Size: 381681 Bytes = 372 kB = 0 MB
3170 Load Address: 00000000
3171 Entry Point: 0000000c
3172 Verifying Checksum ... OK
3173 Uncompressing Kernel Image ... OK
3174 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
3175 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3176 time_init: decrementer frequency = 187500000/60
3177 Calibrating delay loop... 49.77 BogoMIPS
3178 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3181 If you want to boot a Linux kernel with initial ram disk, you pass
3182 the memory addresses of both the kernel and the initrd image (PPBCOOT
3183 format!) to the "bootm" command:
3185 => imi 40100000 40200000
3187 ## Checking Image at 40100000 ...
3188 Image Name: 2.2.13 for initrd on TQM850L
3189 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3190 Data Size: 335725 Bytes = 327 kB = 0 MB
3191 Load Address: 00000000
3192 Entry Point: 0000000c
3193 Verifying Checksum ... OK
3195 ## Checking Image at 40200000 ...
3196 Image Name: Simple Ramdisk Image
3197 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3198 Data Size: 566530 Bytes = 553 kB = 0 MB
3199 Load Address: 00000000
3200 Entry Point: 00000000
3201 Verifying Checksum ... OK
3203 => bootm 40100000 40200000
3204 ## Booting Linux kernel at 40100000 ...
3205 Image Name: 2.2.13 for initrd on TQM850L
3206 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3207 Data Size: 335725 Bytes = 327 kB = 0 MB
3208 Load Address: 00000000
3209 Entry Point: 0000000c
3210 Verifying Checksum ... OK
3211 Uncompressing Kernel Image ... OK
3212 ## Loading RAMDisk Image at 40200000 ...
3213 Image Name: Simple Ramdisk Image
3214 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3215 Data Size: 566530 Bytes = 553 kB = 0 MB
3216 Load Address: 00000000
3217 Entry Point: 00000000
3218 Verifying Checksum ... OK
3219 Loading Ramdisk ... OK
3220 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
3221 Boot arguments: root=/dev/ram
3222 time_init: decrementer frequency = 187500000/60
3223 Calibrating delay loop... 49.77 BogoMIPS
3225 RAMDISK: Compressed image found at block 0
3226 VFS: Mounted root (ext2 filesystem).
3230 Boot Linux and pass a flat device tree:
3233 First, U-Boot must be compiled with the appropriate defines. See the section
3234 titled "Linux Kernel Interface" above for a more in depth explanation. The
3235 following is an example of how to start a kernel and pass an updated
3241 oft=oftrees/mpc8540ads.dtb
3242 => tftp $oftaddr $oft
3243 Speed: 1000, full duplex
3245 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3246 Filename 'oftrees/mpc8540ads.dtb'.
3247 Load address: 0x300000
3250 Bytes transferred = 4106 (100a hex)
3251 => tftp $loadaddr $bootfile
3252 Speed: 1000, full duplex
3254 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3256 Load address: 0x200000
3257 Loading:############
3259 Bytes transferred = 1029407 (fb51f hex)
3264 => bootm $loadaddr - $oftaddr
3265 ## Booting image at 00200000 ...
3266 Image Name: Linux-2.6.17-dirty
3267 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3268 Data Size: 1029343 Bytes = 1005.2 kB
3269 Load Address: 00000000
3270 Entry Point: 00000000
3271 Verifying Checksum ... OK
3272 Uncompressing Kernel Image ... OK
3273 Booting using flat device tree at 0x300000
3274 Using MPC85xx ADS machine description
3275 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3279 More About U-Boot Image Types:
3280 ------------------------------
3282 U-Boot supports the following image types:
3284 "Standalone Programs" are directly runnable in the environment
3285 provided by U-Boot; it is expected that (if they behave
3286 well) you can continue to work in U-Boot after return from
3287 the Standalone Program.
3288 "OS Kernel Images" are usually images of some Embedded OS which
3289 will take over control completely. Usually these programs
3290 will install their own set of exception handlers, device
3291 drivers, set up the MMU, etc. - this means, that you cannot
3292 expect to re-enter U-Boot except by resetting the CPU.
3293 "RAMDisk Images" are more or less just data blocks, and their
3294 parameters (address, size) are passed to an OS kernel that is
3296 "Multi-File Images" contain several images, typically an OS
3297 (Linux) kernel image and one or more data images like
3298 RAMDisks. This construct is useful for instance when you want
3299 to boot over the network using BOOTP etc., where the boot
3300 server provides just a single image file, but you want to get
3301 for instance an OS kernel and a RAMDisk image.
3303 "Multi-File Images" start with a list of image sizes, each
3304 image size (in bytes) specified by an "uint32_t" in network
3305 byte order. This list is terminated by an "(uint32_t)0".
3306 Immediately after the terminating 0 follow the images, one by
3307 one, all aligned on "uint32_t" boundaries (size rounded up to
3308 a multiple of 4 bytes).
3310 "Firmware Images" are binary images containing firmware (like
3311 U-Boot or FPGA images) which usually will be programmed to
3314 "Script files" are command sequences that will be executed by
3315 U-Boot's command interpreter; this feature is especially
3316 useful when you configure U-Boot to use a real shell (hush)
3317 as command interpreter.
3323 One of the features of U-Boot is that you can dynamically load and
3324 run "standalone" applications, which can use some resources of
3325 U-Boot like console I/O functions or interrupt services.
3327 Two simple examples are included with the sources:
3332 'examples/hello_world.c' contains a small "Hello World" Demo
3333 application; it is automatically compiled when you build U-Boot.
3334 It's configured to run at address 0x00040004, so you can play with it
3338 ## Ready for S-Record download ...
3339 ~>examples/hello_world.srec
3340 1 2 3 4 5 6 7 8 9 10 11 ...
3341 [file transfer complete]
3343 ## Start Addr = 0x00040004
3345 => go 40004 Hello World! This is a test.
3346 ## Starting application at 0x00040004 ...
3357 Hit any key to exit ...
3359 ## Application terminated, rc = 0x0
3361 Another example, which demonstrates how to register a CPM interrupt
3362 handler with the U-Boot code, can be found in 'examples/timer.c'.
3363 Here, a CPM timer is set up to generate an interrupt every second.
3364 The interrupt service routine is trivial, just printing a '.'
3365 character, but this is just a demo program. The application can be
3366 controlled by the following keys:
3368 ? - print current values og the CPM Timer registers
3369 b - enable interrupts and start timer
3370 e - stop timer and disable interrupts
3371 q - quit application
3374 ## Ready for S-Record download ...
3375 ~>examples/timer.srec
3376 1 2 3 4 5 6 7 8 9 10 11 ...
3377 [file transfer complete]
3379 ## Start Addr = 0x00040004
3382 ## Starting application at 0x00040004 ...
3385 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3388 [q, b, e, ?] Set interval 1000000 us
3391 [q, b, e, ?] ........
3392 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3395 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3398 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3401 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3403 [q, b, e, ?] ...Stopping timer
3405 [q, b, e, ?] ## Application terminated, rc = 0x0
3411 Over time, many people have reported problems when trying to use the
3412 "minicom" terminal emulation program for serial download. I (wd)
3413 consider minicom to be broken, and recommend not to use it. Under
3414 Unix, I recommend to use C-Kermit for general purpose use (and
3415 especially for kermit binary protocol download ("loadb" command), and
3416 use "cu" for S-Record download ("loads" command).
3418 Nevertheless, if you absolutely want to use it try adding this
3419 configuration to your "File transfer protocols" section:
3421 Name Program Name U/D FullScr IO-Red. Multi
3422 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3423 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3429 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3430 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3432 Building requires a cross environment; it is known to work on
3433 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3434 need gmake since the Makefiles are not compatible with BSD make).
3435 Note that the cross-powerpc package does not install include files;
3436 attempting to build U-Boot will fail because <machine/ansi.h> is
3437 missing. This file has to be installed and patched manually:
3439 # cd /usr/pkg/cross/powerpc-netbsd/include
3441 # ln -s powerpc machine
3442 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3443 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3445 Native builds *don't* work due to incompatibilities between native
3446 and U-Boot include files.
3448 Booting assumes that (the first part of) the image booted is a
3449 stage-2 loader which in turn loads and then invokes the kernel
3450 proper. Loader sources will eventually appear in the NetBSD source
3451 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3452 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3455 Implementation Internals:
3456 =========================
3458 The following is not intended to be a complete description of every
3459 implementation detail. However, it should help to understand the
3460 inner workings of U-Boot and make it easier to port it to custom
3464 Initial Stack, Global Data:
3465 ---------------------------
3467 The implementation of U-Boot is complicated by the fact that U-Boot
3468 starts running out of ROM (flash memory), usually without access to
3469 system RAM (because the memory controller is not initialized yet).
3470 This means that we don't have writable Data or BSS segments, and BSS
3471 is not initialized as zero. To be able to get a C environment working
3472 at all, we have to allocate at least a minimal stack. Implementation
3473 options for this are defined and restricted by the CPU used: Some CPU
3474 models provide on-chip memory (like the IMMR area on MPC8xx and
3475 MPC826x processors), on others (parts of) the data cache can be
3476 locked as (mis-) used as memory, etc.
3478 Chris Hallinan posted a good summary of these issues to the
3479 u-boot-users mailing list:
3481 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3482 From: "Chris Hallinan" <clh@net1plus.com>
3483 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3486 Correct me if I'm wrong, folks, but the way I understand it
3487 is this: Using DCACHE as initial RAM for Stack, etc, does not
3488 require any physical RAM backing up the cache. The cleverness
3489 is that the cache is being used as a temporary supply of
3490 necessary storage before the SDRAM controller is setup. It's
3491 beyond the scope of this list to expain the details, but you
3492 can see how this works by studying the cache architecture and
3493 operation in the architecture and processor-specific manuals.
3495 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3496 is another option for the system designer to use as an
3497 initial stack/ram area prior to SDRAM being available. Either
3498 option should work for you. Using CS 4 should be fine if your
3499 board designers haven't used it for something that would
3500 cause you grief during the initial boot! It is frequently not
3503 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3504 with your processor/board/system design. The default value
3505 you will find in any recent u-boot distribution in
3506 walnut.h should work for you. I'd set it to a value larger
3507 than your SDRAM module. If you have a 64MB SDRAM module, set
3508 it above 400_0000. Just make sure your board has no resources
3509 that are supposed to respond to that address! That code in
3510 start.S has been around a while and should work as is when
3511 you get the config right.
3516 It is essential to remember this, since it has some impact on the C
3517 code for the initialization procedures:
3519 * Initialized global data (data segment) is read-only. Do not attempt
3522 * Do not use any unitialized global data (or implicitely initialized
3523 as zero data - BSS segment) at all - this is undefined, initiali-
3524 zation is performed later (when relocating to RAM).
3526 * Stack space is very limited. Avoid big data buffers or things like
3529 Having only the stack as writable memory limits means we cannot use
3530 normal global data to share information beween the code. But it
3531 turned out that the implementation of U-Boot can be greatly
3532 simplified by making a global data structure (gd_t) available to all
3533 functions. We could pass a pointer to this data as argument to _all_
3534 functions, but this would bloat the code. Instead we use a feature of
3535 the GCC compiler (Global Register Variables) to share the data: we
3536 place a pointer (gd) to the global data into a register which we
3537 reserve for this purpose.
3539 When choosing a register for such a purpose we are restricted by the
3540 relevant (E)ABI specifications for the current architecture, and by
3541 GCC's implementation.
3543 For PowerPC, the following registers have specific use:
3546 R3-R4: parameter passing and return values
3547 R5-R10: parameter passing
3548 R13: small data area pointer
3552 (U-Boot also uses R14 as internal GOT pointer.)
3554 ==> U-Boot will use R29 to hold a pointer to the global data
3556 Note: on PPC, we could use a static initializer (since the
3557 address of the global data structure is known at compile time),
3558 but it turned out that reserving a register results in somewhat
3559 smaller code - although the code savings are not that big (on
3560 average for all boards 752 bytes for the whole U-Boot image,
3561 624 text + 127 data).
3563 On ARM, the following registers are used:
3565 R0: function argument word/integer result
3566 R1-R3: function argument word
3568 R10: stack limit (used only if stack checking if enabled)
3569 R11: argument (frame) pointer
3570 R12: temporary workspace
3573 R15: program counter
3575 ==> U-Boot will use R8 to hold a pointer to the global data
3577 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3578 or current versions of GCC may "optimize" the code too much.
3583 U-Boot runs in system state and uses physical addresses, i.e. the
3584 MMU is not used either for address mapping nor for memory protection.
3586 The available memory is mapped to fixed addresses using the memory
3587 controller. In this process, a contiguous block is formed for each
3588 memory type (Flash, SDRAM, SRAM), even when it consists of several
3589 physical memory banks.
3591 U-Boot is installed in the first 128 kB of the first Flash bank (on
3592 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3593 booting and sizing and initializing DRAM, the code relocates itself
3594 to the upper end of DRAM. Immediately below the U-Boot code some
3595 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3596 configuration setting]. Below that, a structure with global Board
3597 Info data is placed, followed by the stack (growing downward).
3599 Additionally, some exception handler code is copied to the low 8 kB
3600 of DRAM (0x00000000 ... 0x00001FFF).
3602 So a typical memory configuration with 16 MB of DRAM could look like
3605 0x0000 0000 Exception Vector code
3608 0x0000 2000 Free for Application Use
3614 0x00FB FF20 Monitor Stack (Growing downward)
3615 0x00FB FFAC Board Info Data and permanent copy of global data
3616 0x00FC 0000 Malloc Arena
3619 0x00FE 0000 RAM Copy of Monitor Code
3620 ... eventually: LCD or video framebuffer
3621 ... eventually: pRAM (Protected RAM - unchanged by reset)
3622 0x00FF FFFF [End of RAM]
3625 System Initialization:
3626 ----------------------
3628 In the reset configuration, U-Boot starts at the reset entry point
3629 (on most PowerPC systens at address 0x00000100). Because of the reset
3630 configuration for CS0# this is a mirror of the onboard Flash memory.
3631 To be able to re-map memory U-Boot then jumps to its link address.
3632 To be able to implement the initialization code in C, a (small!)
3633 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3634 which provide such a feature like MPC8xx or MPC8260), or in a locked
3635 part of the data cache. After that, U-Boot initializes the CPU core,
3636 the caches and the SIU.
3638 Next, all (potentially) available memory banks are mapped using a
3639 preliminary mapping. For example, we put them on 512 MB boundaries
3640 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3641 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3642 programmed for SDRAM access. Using the temporary configuration, a
3643 simple memory test is run that determines the size of the SDRAM
3646 When there is more than one SDRAM bank, and the banks are of
3647 different size, the largest is mapped first. For equal size, the first
3648 bank (CS2#) is mapped first. The first mapping is always for address
3649 0x00000000, with any additional banks following immediately to create
3650 contiguous memory starting from 0.
3652 Then, the monitor installs itself at the upper end of the SDRAM area
3653 and allocates memory for use by malloc() and for the global Board
3654 Info data; also, the exception vector code is copied to the low RAM
3655 pages, and the final stack is set up.
3657 Only after this relocation will you have a "normal" C environment;
3658 until that you are restricted in several ways, mostly because you are
3659 running from ROM, and because the code will have to be relocated to a
3663 U-Boot Porting Guide:
3664 ----------------------
3666 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3670 int main (int argc, char *argv[])
3672 sighandler_t no_more_time;
3674 signal (SIGALRM, no_more_time);
3675 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3677 if (available_money > available_manpower) {
3678 pay consultant to port U-Boot;
3682 Download latest U-Boot source;
3684 Subscribe to u-boot-users mailing list;
3687 email ("Hi, I am new to U-Boot, how do I get started?");
3691 Read the README file in the top level directory;
3692 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3693 Read the source, Luke;
3696 if (available_money > toLocalCurrency ($2500)) {
3699 Add a lot of aggravation and time;
3702 Create your own board support subdirectory;
3704 Create your own board config file;
3708 Add / modify source code;
3712 email ("Hi, I am having problems...");
3714 Send patch file to Wolfgang;
3719 void no_more_time (int sig)
3728 All contributions to U-Boot should conform to the Linux kernel
3729 coding style; see the file "Documentation/CodingStyle" and the script
3730 "scripts/Lindent" in your Linux kernel source directory. In sources
3731 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3732 spaces before parameters to function calls) is actually used.
3734 Source files originating from a different project (for example the
3735 MTD subsystem) are generally exempt from these guidelines and are not
3736 reformated to ease subsequent migration to newer versions of those
3739 Please note that U-Boot is implemented in C (and to some small parts in
3740 Assembler); no C++ is used, so please do not use C++ style comments (//)
3743 Please also stick to the following formatting rules:
3744 - remove any trailing white space
3745 - use TAB characters for indentation, not spaces
3746 - make sure NOT to use DOS '\r\n' line feeds
3747 - do not add more than 2 empty lines to source files
3748 - do not add trailing empty lines to source files
3750 Submissions which do not conform to the standards may be returned
3751 with a request to reformat the changes.
3757 Since the number of patches for U-Boot is growing, we need to
3758 establish some rules. Submissions which do not conform to these rules
3759 may be rejected, even when they contain important and valuable stuff.
3761 Patches shall be sent to the u-boot-users mailing list.
3763 When you send a patch, please include the following information with
3766 * For bug fixes: a description of the bug and how your patch fixes
3767 this bug. Please try to include a way of demonstrating that the
3768 patch actually fixes something.
3770 * For new features: a description of the feature and your
3773 * A CHANGELOG entry as plaintext (separate from the patch)
3775 * For major contributions, your entry to the CREDITS file
3777 * When you add support for a new board, don't forget to add this
3778 board to the MAKEALL script, too.
3780 * If your patch adds new configuration options, don't forget to
3781 document these in the README file.
3783 * The patch itself. If you are accessing the CVS repository use "cvs
3784 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3785 version of diff does not support these options, then get the latest
3786 version of GNU diff.
3788 The current directory when running this command shall be the top
3789 level directory of the U-Boot source tree, or it's parent directory
3790 (i. e. please make sure that your patch includes sufficient
3791 directory information for the affected files).
3793 We accept patches as plain text, MIME attachments or as uuencoded
3796 * If one logical set of modifications affects or creates several
3797 files, all these changes shall be submitted in a SINGLE patch file.
3799 * Changesets that contain different, unrelated modifications shall be
3800 submitted as SEPARATE patches, one patch per changeset.
3805 * Before sending the patch, run the MAKEALL script on your patched
3806 source tree and make sure that no errors or warnings are reported
3807 for any of the boards.
3809 * Keep your modifications to the necessary minimum: A patch
3810 containing several unrelated changes or arbitrary reformats will be
3811 returned with a request to re-formatting / split it.
3813 * If you modify existing code, make sure that your new code does not
3814 add to the memory footprint of the code ;-) Small is beautiful!
3815 When adding new features, these should compile conditionally only
3816 (using #ifdef), and the resulting code with the new feature
3817 disabled must not need more memory than the old code without your
3820 * Remember that there is a size limit of 40 kB per message on the
3821 u-boot-users mailing list. Compression may help.
git.openpandora.org / pandora-u-boot.git / blob