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
254 MicroBlaze based CPUs:
255 ----------------------
259 ----------------------
263 ----------------------
266 - Board Type: Define exactly one of
268 PowerPC based boards:
269 ---------------------
271 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
272 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
273 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
274 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
275 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
276 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
277 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
278 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
279 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
280 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
281 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
282 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
283 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
284 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
285 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
286 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
287 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
288 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
289 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
290 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
291 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
292 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
293 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
294 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
295 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
296 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
297 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
298 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
299 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
300 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
301 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
302 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
303 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
304 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
305 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
306 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
307 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
308 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
313 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
314 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
315 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
316 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
317 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
318 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
319 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
320 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
323 MicroBlaze based boards:
324 ------------------------
329 ------------------------
331 CONFIG_PCI5441 CONFIG_PK1C20
332 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
339 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
340 Define exactly one of
344 - CPU Module Type: (if CONFIG_COGENT is defined)
345 Define exactly one of
347 --- FIXME --- not tested yet:
348 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
349 CONFIG_CMA287_23, CONFIG_CMA287_50
351 - Motherboard Type: (if CONFIG_COGENT is defined)
352 Define exactly one of
353 CONFIG_CMA101, CONFIG_CMA102
355 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
356 Define one or more of
359 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
360 Define one or more of
361 CONFIG_LCD_HEARTBEAT - update a character position on
362 the lcd display every second with
365 - Board flavour: (if CONFIG_MPC8260ADS is defined)
368 CFG_8260ADS - original MPC8260ADS
369 CFG_8266ADS - MPC8266ADS
370 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
371 CFG_8272ADS - MPC8272ADS
373 - MPC824X Family Member (if CONFIG_MPC824X is defined)
374 Define exactly one of
375 CONFIG_MPC8240, CONFIG_MPC8245
377 - 8xx CPU Options: (if using an MPC8xx cpu)
378 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
379 get_gclk_freq() cannot work
380 e.g. if there is no 32KHz
381 reference PIT/RTC clock
382 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
385 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
388 CONFIG_8xx_CPUCLK_DEFAULT
389 See doc/README.MPC866
393 Define this to measure the actual CPU clock instead
394 of relying on the correctness of the configured
395 values. Mostly useful for board bringup to make sure
396 the PLL is locked at the intended frequency. Note
397 that this requires a (stable) reference clock (32 kHz
398 RTC clock or CFG_8XX_XIN)
400 - Intel Monahans options:
401 CFG_MONAHANS_RUN_MODE_OSC_RATIO
403 Defines the Monahans run mode to oscillator
404 ratio. Valid values are 8, 16, 24, 31. The core
405 frequency is this value multiplied by 13 MHz.
407 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
409 Defines the Monahans turbo mode to oscillator
410 ratio. Valid values are 1 (default if undefined) and
411 2. The core frequency as calculated above is multiplied
414 - Linux Kernel Interface:
417 U-Boot stores all clock information in Hz
418 internally. For binary compatibility with older Linux
419 kernels (which expect the clocks passed in the
420 bd_info data to be in MHz) the environment variable
421 "clocks_in_mhz" can be defined so that U-Boot
422 converts clock data to MHZ before passing it to the
424 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
425 "clocks_in_mhz=1" is automatically included in the
428 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
430 When transfering memsize parameter to linux, some versions
431 expect it to be in bytes, others in MB.
432 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
434 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
436 New kernel versions are expecting firmware settings to be
437 passed using flattened device trees (based on open firmware
441 * New libfdt-based support
442 * Adds the "fdt" command
443 * The bootm command does _not_ modify the fdt
446 * Deprecated, see CONFIG_OF_LIBFDT
447 * Original ft_build.c-based support
448 * Automatically modifies the dft as part of the bootm command
449 * The environment variable "disable_of", when set,
450 disables this functionality.
452 CONFIG_OF_FLAT_TREE_MAX_SIZE
454 The maximum size of the constructed OF tree.
456 OF_CPU - The proper name of the cpus node.
457 OF_SOC - The proper name of the soc node.
458 OF_TBCLK - The timebase frequency.
459 OF_STDOUT_PATH - The path to the console device
463 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
464 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
465 will have a copy of the bd_t. Space should be
466 pre-allocated in the dts for the bd_t.
468 CONFIG_OF_HAS_UBOOT_ENV
470 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
471 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
472 will have a copy of u-boot's environment variables
474 CONFIG_OF_BOARD_SETUP
476 Board code has addition modification that it wants to make
477 to the flat device tree before handing it off to the kernel
481 This define fills in the correct boot cpu in the boot
482 param header, the default value is zero if undefined.
487 Define this if you want support for Amba PrimeCell PL010 UARTs.
491 Define this if you want support for Amba PrimeCell PL011 UARTs.
495 If you have Amba PrimeCell PL011 UARTs, set this variable to
496 the clock speed of the UARTs.
500 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
501 define this to a list of base addresses for each (supported)
502 port. See e.g. include/configs/versatile.h
506 Depending on board, define exactly one serial port
507 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
508 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
509 console by defining CONFIG_8xx_CONS_NONE
511 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
512 port routines must be defined elsewhere
513 (i.e. serial_init(), serial_getc(), ...)
516 Enables console device for a color framebuffer. Needs following
517 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
518 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
520 VIDEO_HW_RECTFILL graphic chip supports
523 VIDEO_HW_BITBLT graphic chip supports
524 bit-blit (cf. smiLynxEM)
525 VIDEO_VISIBLE_COLS visible pixel columns
527 VIDEO_VISIBLE_ROWS visible pixel rows
528 VIDEO_PIXEL_SIZE bytes per pixel
529 VIDEO_DATA_FORMAT graphic data format
530 (0-5, cf. cfb_console.c)
531 VIDEO_FB_ADRS framebuffer address
532 VIDEO_KBD_INIT_FCT keyboard int fct
533 (i.e. i8042_kbd_init())
534 VIDEO_TSTC_FCT test char fct
536 VIDEO_GETC_FCT get char fct
538 CONFIG_CONSOLE_CURSOR cursor drawing on/off
539 (requires blink timer
541 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
542 CONFIG_CONSOLE_TIME display time/date info in
544 (requires CFG_CMD_DATE)
545 CONFIG_VIDEO_LOGO display Linux logo in
547 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
548 linux_logo.h for logo.
549 Requires CONFIG_VIDEO_LOGO
550 CONFIG_CONSOLE_EXTRA_INFO
551 addional board info beside
554 When CONFIG_CFB_CONSOLE is defined, video console is
555 default i/o. Serial console can be forced with
556 environment 'console=serial'.
558 When CONFIG_SILENT_CONSOLE is defined, all console
559 messages (by U-Boot and Linux!) can be silenced with
560 the "silent" environment variable. See
561 doc/README.silent for more information.
564 CONFIG_BAUDRATE - in bps
565 Select one of the baudrates listed in
566 CFG_BAUDRATE_TABLE, see below.
567 CFG_BRGCLK_PRESCALE, baudrate prescale
569 - Interrupt driven serial port input:
570 CONFIG_SERIAL_SOFTWARE_FIFO
573 Use an interrupt handler for receiving data on the
574 serial port. It also enables using hardware handshake
575 (RTS/CTS) and UART's built-in FIFO. Set the number of
576 bytes the interrupt driven input buffer should have.
578 Leave undefined to disable this feature, including
579 disable the buffer and hardware handshake.
581 - Console UART Number:
585 If defined internal UART1 (and not UART0) is used
586 as default U-Boot console.
588 - Boot Delay: CONFIG_BOOTDELAY - in seconds
589 Delay before automatically booting the default image;
590 set to -1 to disable autoboot.
592 See doc/README.autoboot for these options that
593 work with CONFIG_BOOTDELAY. None are required.
594 CONFIG_BOOT_RETRY_TIME
595 CONFIG_BOOT_RETRY_MIN
596 CONFIG_AUTOBOOT_KEYED
597 CONFIG_AUTOBOOT_PROMPT
598 CONFIG_AUTOBOOT_DELAY_STR
599 CONFIG_AUTOBOOT_STOP_STR
600 CONFIG_AUTOBOOT_DELAY_STR2
601 CONFIG_AUTOBOOT_STOP_STR2
602 CONFIG_ZERO_BOOTDELAY_CHECK
603 CONFIG_RESET_TO_RETRY
607 Only needed when CONFIG_BOOTDELAY is enabled;
608 define a command string that is automatically executed
609 when no character is read on the console interface
610 within "Boot Delay" after reset.
613 This can be used to pass arguments to the bootm
614 command. The value of CONFIG_BOOTARGS goes into the
615 environment value "bootargs".
617 CONFIG_RAMBOOT and CONFIG_NFSBOOT
618 The value of these goes into the environment as
619 "ramboot" and "nfsboot" respectively, and can be used
620 as a convenience, when switching between booting from
626 When this option is #defined, the existence of the
627 environment variable "preboot" will be checked
628 immediately before starting the CONFIG_BOOTDELAY
629 countdown and/or running the auto-boot command resp.
630 entering interactive mode.
632 This feature is especially useful when "preboot" is
633 automatically generated or modified. For an example
634 see the LWMON board specific code: here "preboot" is
635 modified when the user holds down a certain
636 combination of keys on the (special) keyboard when
639 - Serial Download Echo Mode:
641 If defined to 1, all characters received during a
642 serial download (using the "loads" command) are
643 echoed back. This might be needed by some terminal
644 emulations (like "cu"), but may as well just take
645 time on others. This setting #define's the initial
646 value of the "loads_echo" environment variable.
648 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
650 Select one of the baudrates listed in
651 CFG_BAUDRATE_TABLE, see below.
655 Most monitor functions can be selected (or
656 de-selected) by adjusting the definition of
657 CONFIG_COMMANDS; to select individual functions,
658 #define CONFIG_COMMANDS by "OR"ing any of the
661 #define enables commands:
662 -------------------------
663 CFG_CMD_ASKENV * ask for env variable
664 CFG_CMD_AUTOSCRIPT Autoscript Support
666 CFG_CMD_BEDBUG * Include BedBug Debugger
667 CFG_CMD_BMP * BMP support
668 CFG_CMD_BSP * Board specific commands
670 CFG_CMD_CACHE * icache, dcache
671 CFG_CMD_CONSOLE coninfo
672 CFG_CMD_DATE * support for RTC, date/time...
673 CFG_CMD_DHCP * DHCP support
674 CFG_CMD_DIAG * Diagnostics
675 CFG_CMD_DOC * Disk-On-Chip Support
676 CFG_CMD_DTT * Digital Therm and Thermostat
677 CFG_CMD_ECHO echo arguments
678 CFG_CMD_EEPROM * EEPROM read/write support
679 CFG_CMD_ELF * bootelf, bootvx
681 CFG_CMD_FDC * Floppy Disk Support
682 CFG_CMD_FAT * FAT partition support
683 CFG_CMD_FDOS * Dos diskette Support
684 CFG_CMD_FLASH flinfo, erase, protect
685 CFG_CMD_FPGA FPGA device initialization support
686 CFG_CMD_HWFLOW * RTS/CTS hw flow control
687 CFG_CMD_I2C * I2C serial bus support
688 CFG_CMD_IDE * IDE harddisk support
690 CFG_CMD_IMLS List all found images
691 CFG_CMD_IMMAP * IMMR dump support
692 CFG_CMD_IRQ * irqinfo
693 CFG_CMD_ITEST Integer/string test of 2 values
694 CFG_CMD_JFFS2 * JFFS2 Support
698 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
700 CFG_CMD_MISC Misc functions like sleep etc
701 CFG_CMD_MMC * MMC memory mapped support
702 CFG_CMD_MII * MII utility commands
703 CFG_CMD_NAND * NAND support
704 CFG_CMD_NET bootp, tftpboot, rarpboot
705 CFG_CMD_PCI * pciinfo
706 CFG_CMD_PCMCIA * PCMCIA support
707 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
708 CFG_CMD_PORTIO * Port I/O
709 CFG_CMD_REGINFO * Register dump
710 CFG_CMD_RUN run command in env variable
711 CFG_CMD_SAVES * save S record dump
712 CFG_CMD_SCSI * SCSI Support
713 CFG_CMD_SDRAM * print SDRAM configuration information
714 (requires CFG_CMD_I2C)
715 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
716 CFG_CMD_SPI * SPI serial bus support
717 CFG_CMD_USB * USB support
718 CFG_CMD_VFD * VFD support (TRAB)
719 CFG_CMD_BSP * Board SPecific functions
720 CFG_CMD_CDP * Cisco Discover Protocol support
721 CFG_CMD_FSL * Microblaze FSL 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
906 The MMC controller on the Intel PXA is supported. To
907 enable this define CONFIG_MMC. The MMC can be
908 accessed from the boot prompt by mapping the device
909 to physical memory similar to flash. Command line is
910 enabled with CFG_CMD_MMC. The MMC driver also works with
911 the FAT fs. This is enabled with CFG_CMD_FAT.
913 - Journaling Flash filesystem support:
914 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
915 CONFIG_JFFS2_NAND_DEV
916 Define these for a default partition on a NAND device
918 CFG_JFFS2_FIRST_SECTOR,
919 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
920 Define these for a default partition on a NOR device
923 Define this to create an own partition. You have to provide a
924 function struct part_info* jffs2_part_info(int part_num)
926 If you define only one JFFS2 partition you may also want to
927 #define CFG_JFFS_SINGLE_PART 1
928 to disable the command chpart. This is the default when you
929 have not defined a custom partition
934 Define this to enable standard (PC-Style) keyboard
938 Standard PC keyboard driver with US (is default) and
939 GERMAN key layout (switch via environment 'keymap=de') support.
940 Export function i8042_kbd_init, i8042_tstc and i8042_getc
941 for cfb_console. Supports cursor blinking.
946 Define this to enable video support (for output to
951 Enable Chips & Technologies 69000 Video chip
953 CONFIG_VIDEO_SMI_LYNXEM
954 Enable Silicon Motion SMI 712/710/810 Video chip. The
955 video output is selected via environment 'videoout'
956 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
959 For the CT69000 and SMI_LYNXEM drivers, videomode is
960 selected via environment 'videomode'. Two diferent ways
962 - "videomode=num" 'num' is a standard LiLo mode numbers.
963 Following standard modes are supported (* is default):
965 Colors 640x480 800x600 1024x768 1152x864 1280x1024
966 -------------+---------------------------------------------
967 8 bits | 0x301* 0x303 0x305 0x161 0x307
968 15 bits | 0x310 0x313 0x316 0x162 0x319
969 16 bits | 0x311 0x314 0x317 0x163 0x31A
970 24 bits | 0x312 0x315 0x318 ? 0x31B
971 -------------+---------------------------------------------
972 (i.e. setenv videomode 317; saveenv; reset;)
974 - "videomode=bootargs" all the video parameters are parsed
975 from the bootargs. (See drivers/videomodes.c)
978 CONFIG_VIDEO_SED13806
979 Enable Epson SED13806 driver. This driver supports 8bpp
980 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
981 or CONFIG_VIDEO_SED13806_16BPP
986 Define this to enable a custom keyboard support.
987 This simply calls drv_keyboard_init() which must be
988 defined in your board-specific files.
989 The only board using this so far is RBC823.
991 - LCD Support: CONFIG_LCD
993 Define this to enable LCD support (for output to LCD
994 display); also select one of the supported displays
995 by defining one of these:
997 CONFIG_NEC_NL6448AC33:
999 NEC NL6448AC33-18. Active, color, single scan.
1001 CONFIG_NEC_NL6448BC20
1003 NEC NL6448BC20-08. 6.5", 640x480.
1004 Active, color, single scan.
1006 CONFIG_NEC_NL6448BC33_54
1008 NEC NL6448BC33-54. 10.4", 640x480.
1009 Active, color, single scan.
1013 Sharp 320x240. Active, color, single scan.
1014 It isn't 16x9, and I am not sure what it is.
1016 CONFIG_SHARP_LQ64D341
1018 Sharp LQ64D341 display, 640x480.
1019 Active, color, single scan.
1023 HLD1045 display, 640x480.
1024 Active, color, single scan.
1028 Optrex CBL50840-2 NF-FW 99 22 M5
1030 Hitachi LMG6912RPFC-00T
1034 320x240. Black & white.
1036 Normally display is black on white background; define
1037 CFG_WHITE_ON_BLACK to get it inverted.
1039 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1041 If this option is set, the environment is checked for
1042 a variable "splashimage". If found, the usual display
1043 of logo, copyright and system information on the LCD
1044 is suppressed and the BMP image at the address
1045 specified in "splashimage" is loaded instead. The
1046 console is redirected to the "nulldev", too. This
1047 allows for a "silent" boot where a splash screen is
1048 loaded very quickly after power-on.
1050 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1052 If this option is set, additionally to standard BMP
1053 images, gzipped BMP images can be displayed via the
1054 splashscreen support or the bmp command.
1056 - Compression support:
1059 If this option is set, support for bzip2 compressed
1060 images is included. If not, only uncompressed and gzip
1061 compressed images are supported.
1063 NOTE: the bzip2 algorithm requires a lot of RAM, so
1064 the malloc area (as defined by CFG_MALLOC_LEN) should
1070 The address of PHY on MII bus.
1072 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1074 The clock frequency of the MII bus
1078 If this option is set, support for speed/duplex
1079 detection of Gigabit PHY is included.
1081 CONFIG_PHY_RESET_DELAY
1083 Some PHY like Intel LXT971A need extra delay after
1084 reset before any MII register access is possible.
1085 For such PHY, set this option to the usec delay
1086 required. (minimum 300usec for LXT971A)
1088 CONFIG_PHY_CMD_DELAY (ppc4xx)
1090 Some PHY like Intel LXT971A need extra delay after
1091 command issued before MII status register can be read
1098 Define a default value for ethernet address to use
1099 for the respective ethernet interface, in case this
1100 is not determined automatically.
1105 Define a default value for the IP address to use for
1106 the default ethernet interface, in case this is not
1107 determined through e.g. bootp.
1109 - Server IP address:
1112 Defines a default value for theIP address of a TFTP
1113 server to contact when using the "tftboot" command.
1115 - BOOTP Recovery Mode:
1116 CONFIG_BOOTP_RANDOM_DELAY
1118 If you have many targets in a network that try to
1119 boot using BOOTP, you may want to avoid that all
1120 systems send out BOOTP requests at precisely the same
1121 moment (which would happen for instance at recovery
1122 from a power failure, when all systems will try to
1123 boot, thus flooding the BOOTP server. Defining
1124 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1125 inserted before sending out BOOTP requests. The
1126 following delays are insterted then:
1128 1st BOOTP request: delay 0 ... 1 sec
1129 2nd BOOTP request: delay 0 ... 2 sec
1130 3rd BOOTP request: delay 0 ... 4 sec
1132 BOOTP requests: delay 0 ... 8 sec
1134 - DHCP Advanced Options:
1137 You can fine tune the DHCP functionality by adding
1138 these flags to the CONFIG_BOOTP_MASK define:
1140 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1141 serverip from a DHCP server, it is possible that more
1142 than one DNS serverip is offered to the client.
1143 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1144 serverip will be stored in the additional environment
1145 variable "dnsip2". The first DNS serverip is always
1146 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1147 is added to the CONFIG_BOOTP_MASK.
1149 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1150 to do a dynamic update of a DNS server. To do this, they
1151 need the hostname of the DHCP requester.
1152 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1153 CONFIG_BOOTP_MASK, the content of the "hostname"
1154 environment variable is passed as option 12 to
1158 CONFIG_CDP_DEVICE_ID
1160 The device id used in CDP trigger frames.
1162 CONFIG_CDP_DEVICE_ID_PREFIX
1164 A two character string which is prefixed to the MAC address
1169 A printf format string which contains the ascii name of
1170 the port. Normally is set to "eth%d" which sets
1171 eth0 for the first ethernet, eth1 for the second etc.
1173 CONFIG_CDP_CAPABILITIES
1175 A 32bit integer which indicates the device capabilities;
1176 0x00000010 for a normal host which does not forwards.
1180 An ascii string containing the version of the software.
1184 An ascii string containing the name of the platform.
1188 A 32bit integer sent on the trigger.
1190 CONFIG_CDP_POWER_CONSUMPTION
1192 A 16bit integer containing the power consumption of the
1193 device in .1 of milliwatts.
1195 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1197 A byte containing the id of the VLAN.
1199 - Status LED: CONFIG_STATUS_LED
1201 Several configurations allow to display the current
1202 status using a LED. For instance, the LED will blink
1203 fast while running U-Boot code, stop blinking as
1204 soon as a reply to a BOOTP request was received, and
1205 start blinking slow once the Linux kernel is running
1206 (supported by a status LED driver in the Linux
1207 kernel). Defining CONFIG_STATUS_LED enables this
1210 - CAN Support: CONFIG_CAN_DRIVER
1212 Defining CONFIG_CAN_DRIVER enables CAN driver support
1213 on those systems that support this (optional)
1214 feature, like the TQM8xxL modules.
1216 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1218 These enable I2C serial bus commands. Defining either of
1219 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1220 include the appropriate I2C driver for the selected cpu.
1222 This will allow you to use i2c commands at the u-boot
1223 command line (as long as you set CFG_CMD_I2C in
1224 CONFIG_COMMANDS) and communicate with i2c based realtime
1225 clock chips. See common/cmd_i2c.c for a description of the
1226 command line interface.
1228 CONFIG_I2C_CMD_TREE is a recommended option that places
1229 all I2C commands under a single 'i2c' root command. The
1230 older 'imm', 'imd', 'iprobe' etc. commands are considered
1231 deprecated and may disappear in the future.
1233 CONFIG_HARD_I2C selects a hardware I2C controller.
1235 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1236 bit-banging) driver instead of CPM or similar hardware
1239 There are several other quantities that must also be
1240 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1242 In both cases you will need to define CFG_I2C_SPEED
1243 to be the frequency (in Hz) at which you wish your i2c bus
1244 to run and CFG_I2C_SLAVE to be the address of this node (ie
1245 the cpu's i2c node address).
1247 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1248 sets the cpu up as a master node and so its address should
1249 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1250 p.16-473). So, set CFG_I2C_SLAVE to 0.
1252 That's all that's required for CONFIG_HARD_I2C.
1254 If you use the software i2c interface (CONFIG_SOFT_I2C)
1255 then the following macros need to be defined (examples are
1256 from include/configs/lwmon.h):
1260 (Optional). Any commands necessary to enable the I2C
1261 controller or configure ports.
1263 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1267 (Only for MPC8260 CPU). The I/O port to use (the code
1268 assumes both bits are on the same port). Valid values
1269 are 0..3 for ports A..D.
1273 The code necessary to make the I2C data line active
1274 (driven). If the data line is open collector, this
1277 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1281 The code necessary to make the I2C data line tri-stated
1282 (inactive). If the data line is open collector, this
1285 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1289 Code that returns TRUE if the I2C data line is high,
1292 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1296 If <bit> is TRUE, sets the I2C data line high. If it
1297 is FALSE, it clears it (low).
1299 eg: #define I2C_SDA(bit) \
1300 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1301 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1305 If <bit> is TRUE, sets the I2C clock line high. If it
1306 is FALSE, it clears it (low).
1308 eg: #define I2C_SCL(bit) \
1309 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1310 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1314 This delay is invoked four times per clock cycle so this
1315 controls the rate of data transfer. The data rate thus
1316 is 1 / (I2C_DELAY * 4). Often defined to be something
1319 #define I2C_DELAY udelay(2)
1323 When a board is reset during an i2c bus transfer
1324 chips might think that the current transfer is still
1325 in progress. On some boards it is possible to access
1326 the i2c SCLK line directly, either by using the
1327 processor pin as a GPIO or by having a second pin
1328 connected to the bus. If this option is defined a
1329 custom i2c_init_board() routine in boards/xxx/board.c
1330 is run early in the boot sequence.
1332 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1334 This option enables configuration of bi_iic_fast[] flags
1335 in u-boot bd_info structure based on u-boot environment
1336 variable "i2cfast". (see also i2cfast)
1338 CONFIG_I2C_MULTI_BUS
1340 This option allows the use of multiple I2C buses, each of which
1341 must have a controller. At any point in time, only one bus is
1342 active. To switch to a different bus, use the 'i2c dev' command.
1343 Note that bus numbering is zero-based.
1347 This option specifies a list of I2C devices that will be skipped
1348 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1349 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1350 pairs. Otherwise, specify a 1D array of device addresses
1353 #undef CONFIG_I2C_MULTI_BUS
1354 #define CFG_I2C_NOPROBES {0x50,0x68}
1356 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1358 #define CONFIG_I2C_MULTI_BUS
1359 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1361 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1365 If defined, then this indicates the I2C bus number for DDR SPD.
1366 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1370 If defined, then this indicates the I2C bus number for the RTC.
1371 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1375 If defined, then this indicates the I2C bus number for the DTT.
1376 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1380 Define this option if you want to use Freescale's I2C driver in
1384 - SPI Support: CONFIG_SPI
1386 Enables SPI driver (so far only tested with
1387 SPI EEPROM, also an instance works with Crystal A/D and
1388 D/As on the SACSng board)
1392 Enables extended (16-bit) SPI EEPROM addressing.
1393 (symmetrical to CONFIG_I2C_X)
1397 Enables a software (bit-bang) SPI driver rather than
1398 using hardware support. This is a general purpose
1399 driver that only requires three general I/O port pins
1400 (two outputs, one input) to function. If this is
1401 defined, the board configuration must define several
1402 SPI configuration items (port pins to use, etc). For
1403 an example, see include/configs/sacsng.h.
1405 - FPGA Support: CONFIG_FPGA_COUNT
1407 Specify the number of FPGA devices to support.
1411 Used to specify the types of FPGA devices. For example,
1412 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1414 CFG_FPGA_PROG_FEEDBACK
1416 Enable printing of hash marks during FPGA configuration.
1420 Enable checks on FPGA configuration interface busy
1421 status by the configuration function. This option
1422 will require a board or device specific function to
1427 If defined, a function that provides delays in the FPGA
1428 configuration driver.
1430 CFG_FPGA_CHECK_CTRLC
1431 Allow Control-C to interrupt FPGA configuration
1433 CFG_FPGA_CHECK_ERROR
1435 Check for configuration errors during FPGA bitfile
1436 loading. For example, abort during Virtex II
1437 configuration if the INIT_B line goes low (which
1438 indicated a CRC error).
1442 Maximum time to wait for the INIT_B line to deassert
1443 after PROB_B has been deasserted during a Virtex II
1444 FPGA configuration sequence. The default time is 500
1449 Maximum time to wait for BUSY to deassert during
1450 Virtex II FPGA configuration. The default is 5 mS.
1452 CFG_FPGA_WAIT_CONFIG
1454 Time to wait after FPGA configuration. The default is
1457 - Configuration Management:
1460 If defined, this string will be added to the U-Boot
1461 version information (U_BOOT_VERSION)
1463 - Vendor Parameter Protection:
1465 U-Boot considers the values of the environment
1466 variables "serial#" (Board Serial Number) and
1467 "ethaddr" (Ethernet Address) to be parameters that
1468 are set once by the board vendor / manufacturer, and
1469 protects these variables from casual modification by
1470 the user. Once set, these variables are read-only,
1471 and write or delete attempts are rejected. You can
1472 change this behviour:
1474 If CONFIG_ENV_OVERWRITE is #defined in your config
1475 file, the write protection for vendor parameters is
1476 completely disabled. Anybody can change or delete
1479 Alternatively, if you #define _both_ CONFIG_ETHADDR
1480 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1481 ethernet address is installed in the environment,
1482 which can be changed exactly ONCE by the user. [The
1483 serial# is unaffected by this, i. e. it remains
1489 Define this variable to enable the reservation of
1490 "protected RAM", i. e. RAM which is not overwritten
1491 by U-Boot. Define CONFIG_PRAM to hold the number of
1492 kB you want to reserve for pRAM. You can overwrite
1493 this default value by defining an environment
1494 variable "pram" to the number of kB you want to
1495 reserve. Note that the board info structure will
1496 still show the full amount of RAM. If pRAM is
1497 reserved, a new environment variable "mem" will
1498 automatically be defined to hold the amount of
1499 remaining RAM in a form that can be passed as boot
1500 argument to Linux, for instance like that:
1502 setenv bootargs ... mem=\${mem}
1505 This way you can tell Linux not to use this memory,
1506 either, which results in a memory region that will
1507 not be affected by reboots.
1509 *WARNING* If your board configuration uses automatic
1510 detection of the RAM size, you must make sure that
1511 this memory test is non-destructive. So far, the
1512 following board configurations are known to be
1515 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1516 HERMES, IP860, RPXlite, LWMON, LANTEC,
1517 PCU_E, FLAGADM, TQM8260
1522 Define this variable to stop the system in case of a
1523 fatal error, so that you have to reset it manually.
1524 This is probably NOT a good idea for an embedded
1525 system where you want to system to reboot
1526 automatically as fast as possible, but it may be
1527 useful during development since you can try to debug
1528 the conditions that lead to the situation.
1530 CONFIG_NET_RETRY_COUNT
1532 This variable defines the number of retries for
1533 network operations like ARP, RARP, TFTP, or BOOTP
1534 before giving up the operation. If not defined, a
1535 default value of 5 is used.
1537 - Command Interpreter:
1538 CONFIG_AUTO_COMPLETE
1540 Enable auto completion of commands using TAB.
1542 Note that this feature has NOT been implemented yet
1543 for the "hush" shell.
1548 Define this variable to enable the "hush" shell (from
1549 Busybox) as command line interpreter, thus enabling
1550 powerful command line syntax like
1551 if...then...else...fi conditionals or `&&' and '||'
1552 constructs ("shell scripts").
1554 If undefined, you get the old, much simpler behaviour
1555 with a somewhat smaller memory footprint.
1560 This defines the secondary prompt string, which is
1561 printed when the command interpreter needs more input
1562 to complete a command. Usually "> ".
1566 In the current implementation, the local variables
1567 space and global environment variables space are
1568 separated. Local variables are those you define by
1569 simply typing `name=value'. To access a local
1570 variable later on, you have write `$name' or
1571 `${name}'; to execute the contents of a variable
1572 directly type `$name' at the command prompt.
1574 Global environment variables are those you use
1575 setenv/printenv to work with. To run a command stored
1576 in such a variable, you need to use the run command,
1577 and you must not use the '$' sign to access them.
1579 To store commands and special characters in a
1580 variable, please use double quotation marks
1581 surrounding the whole text of the variable, instead
1582 of the backslashes before semicolons and special
1585 - Commandline Editing and History:
1586 CONFIG_CMDLINE_EDITING
1588 Enable editiong and History functions for interactive
1589 commandline input operations
1591 - Default Environment:
1592 CONFIG_EXTRA_ENV_SETTINGS
1594 Define this to contain any number of null terminated
1595 strings (variable = value pairs) that will be part of
1596 the default environment compiled into the boot image.
1598 For example, place something like this in your
1599 board's config file:
1601 #define CONFIG_EXTRA_ENV_SETTINGS \
1605 Warning: This method is based on knowledge about the
1606 internal format how the environment is stored by the
1607 U-Boot code. This is NOT an official, exported
1608 interface! Although it is unlikely that this format
1609 will change soon, there is no guarantee either.
1610 You better know what you are doing here.
1612 Note: overly (ab)use of the default environment is
1613 discouraged. Make sure to check other ways to preset
1614 the environment like the autoscript function or the
1617 - DataFlash Support:
1618 CONFIG_HAS_DATAFLASH
1620 Defining this option enables DataFlash features and
1621 allows to read/write in Dataflash via the standard
1624 - SystemACE Support:
1627 Adding this option adds support for Xilinx SystemACE
1628 chips attached via some sort of local bus. The address
1629 of the chip must alsh be defined in the
1630 CFG_SYSTEMACE_BASE macro. For example:
1632 #define CONFIG_SYSTEMACE
1633 #define CFG_SYSTEMACE_BASE 0xf0000000
1635 When SystemACE support is added, the "ace" device type
1636 becomes available to the fat commands, i.e. fatls.
1638 - TFTP Fixed UDP Port:
1641 If this is defined, the environment variable tftpsrcp
1642 is used to supply the TFTP UDP source port value.
1643 If tftpsrcp isn't defined, the normal pseudo-random port
1644 number generator is used.
1646 Also, the environment variable tftpdstp is used to supply
1647 the TFTP UDP destination port value. If tftpdstp isn't
1648 defined, the normal port 69 is used.
1650 The purpose for tftpsrcp is to allow a TFTP server to
1651 blindly start the TFTP transfer using the pre-configured
1652 target IP address and UDP port. This has the effect of
1653 "punching through" the (Windows XP) firewall, allowing
1654 the remainder of the TFTP transfer to proceed normally.
1655 A better solution is to properly configure the firewall,
1656 but sometimes that is not allowed.
1658 - Show boot progress:
1659 CONFIG_SHOW_BOOT_PROGRESS
1661 Defining this option allows to add some board-
1662 specific code (calling a user-provided function
1663 "show_boot_progress(int)") that enables you to show
1664 the system's boot progress on some display (for
1665 example, some LED's) on your board. At the moment,
1666 the following checkpoints are implemented:
1669 1 common/cmd_bootm.c before attempting to boot an image
1670 -1 common/cmd_bootm.c Image header has bad magic number
1671 2 common/cmd_bootm.c Image header has correct magic number
1672 -2 common/cmd_bootm.c Image header has bad checksum
1673 3 common/cmd_bootm.c Image header has correct checksum
1674 -3 common/cmd_bootm.c Image data has bad checksum
1675 4 common/cmd_bootm.c Image data has correct checksum
1676 -4 common/cmd_bootm.c Image is for unsupported architecture
1677 5 common/cmd_bootm.c Architecture check OK
1678 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1679 6 common/cmd_bootm.c Image Type check OK
1680 -6 common/cmd_bootm.c gunzip uncompression error
1681 -7 common/cmd_bootm.c Unimplemented compression type
1682 7 common/cmd_bootm.c Uncompression OK
1683 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1684 8 common/cmd_bootm.c Image Type check OK
1685 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1686 9 common/cmd_bootm.c Start initial ramdisk verification
1687 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1688 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1689 10 common/cmd_bootm.c Ramdisk header is OK
1690 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1691 11 common/cmd_bootm.c Ramdisk data has correct checksum
1692 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1693 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1694 13 common/cmd_bootm.c Start multifile image verification
1695 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1696 15 common/cmd_bootm.c All preparation done, transferring control to OS
1698 -30 lib_ppc/board.c Fatal error, hang the system
1699 -31 post/post.c POST test failed, detected by post_output_backlog()
1700 -32 post/post.c POST test failed, detected by post_run_single()
1702 -1 common/cmd_doc.c Bad usage of "doc" command
1703 -1 common/cmd_doc.c No boot device
1704 -1 common/cmd_doc.c Unknown Chip ID on boot device
1705 -1 common/cmd_doc.c Read Error on boot device
1706 -1 common/cmd_doc.c Image header has bad magic number
1708 -1 common/cmd_ide.c Bad usage of "ide" command
1709 -1 common/cmd_ide.c No boot device
1710 -1 common/cmd_ide.c Unknown boot device
1711 -1 common/cmd_ide.c Unknown partition table
1712 -1 common/cmd_ide.c Invalid partition type
1713 -1 common/cmd_ide.c Read Error on boot device
1714 -1 common/cmd_ide.c Image header has bad magic number
1716 -1 common/cmd_nand.c Bad usage of "nand" command
1717 -1 common/cmd_nand.c No boot device
1718 -1 common/cmd_nand.c Unknown Chip ID on boot device
1719 -1 common/cmd_nand.c Read Error on boot device
1720 -1 common/cmd_nand.c Image header has bad magic number
1722 -1 common/env_common.c Environment has a bad CRC, using default
1728 [so far only for SMDK2400 and TRAB boards]
1730 - Modem support endable:
1731 CONFIG_MODEM_SUPPORT
1733 - RTS/CTS Flow control enable:
1736 - Modem debug support:
1737 CONFIG_MODEM_SUPPORT_DEBUG
1739 Enables debugging stuff (char screen[1024], dbg())
1740 for modem support. Useful only with BDI2000.
1742 - Interrupt support (PPC):
1744 There are common interrupt_init() and timer_interrupt()
1745 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1746 for cpu specific initialization. interrupt_init_cpu()
1747 should set decrementer_count to appropriate value. If
1748 cpu resets decrementer automatically after interrupt
1749 (ppc4xx) it should set decrementer_count to zero.
1750 timer_interrupt() calls timer_interrupt_cpu() for cpu
1751 specific handling. If board has watchdog / status_led
1752 / other_activity_monitor it works automatically from
1753 general timer_interrupt().
1757 In the target system modem support is enabled when a
1758 specific key (key combination) is pressed during
1759 power-on. Otherwise U-Boot will boot normally
1760 (autoboot). The key_pressed() fuction is called from
1761 board_init(). Currently key_pressed() is a dummy
1762 function, returning 1 and thus enabling modem
1765 If there are no modem init strings in the
1766 environment, U-Boot proceed to autoboot; the
1767 previous output (banner, info printfs) will be
1770 See also: doc/README.Modem
1773 Configuration Settings:
1774 -----------------------
1776 - CFG_LONGHELP: Defined when you want long help messages included;
1777 undefine this when you're short of memory.
1779 - CFG_PROMPT: This is what U-Boot prints on the console to
1780 prompt for user input.
1782 - CFG_CBSIZE: Buffer size for input from the Console
1784 - CFG_PBSIZE: Buffer size for Console output
1786 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1788 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1789 the application (usually a Linux kernel) when it is
1792 - CFG_BAUDRATE_TABLE:
1793 List of legal baudrate settings for this board.
1795 - CFG_CONSOLE_INFO_QUIET
1796 Suppress display of console information at boot.
1798 - CFG_CONSOLE_IS_IN_ENV
1799 If the board specific function
1800 extern int overwrite_console (void);
1801 returns 1, the stdin, stderr and stdout are switched to the
1802 serial port, else the settings in the environment are used.
1804 - CFG_CONSOLE_OVERWRITE_ROUTINE
1805 Enable the call to overwrite_console().
1807 - CFG_CONSOLE_ENV_OVERWRITE
1808 Enable overwrite of previous console environment settings.
1810 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1811 Begin and End addresses of the area used by the
1815 Enable an alternate, more extensive memory test.
1817 - CFG_MEMTEST_SCRATCH:
1818 Scratch address used by the alternate memory test
1819 You only need to set this if address zero isn't writeable
1821 - CFG_TFTP_LOADADDR:
1822 Default load address for network file downloads
1824 - CFG_LOADS_BAUD_CHANGE:
1825 Enable temporary baudrate change while serial download
1828 Physical start address of SDRAM. _Must_ be 0 here.
1831 Physical start address of Motherboard I/O (if using a
1835 Physical start address of Flash memory.
1838 Physical start address of boot monitor code (set by
1839 make config files to be same as the text base address
1840 (TEXT_BASE) used when linking) - same as
1841 CFG_FLASH_BASE when booting from flash.
1844 Size of memory reserved for monitor code, used to
1845 determine _at_compile_time_ (!) if the environment is
1846 embedded within the U-Boot image, or in a separate
1850 Size of DRAM reserved for malloc() use.
1853 Normally compressed uImages are limited to an
1854 uncompressed size of 8 MBytes. If this is not enough,
1855 you can define CFG_BOOTM_LEN in your board config file
1856 to adjust this setting to your needs.
1859 Maximum size of memory mapped by the startup code of
1860 the Linux kernel; all data that must be processed by
1861 the Linux kernel (bd_info, boot arguments, eventually
1862 initrd image) must be put below this limit.
1864 - CFG_MAX_FLASH_BANKS:
1865 Max number of Flash memory banks
1867 - CFG_MAX_FLASH_SECT:
1868 Max number of sectors on a Flash chip
1870 - CFG_FLASH_ERASE_TOUT:
1871 Timeout for Flash erase operations (in ms)
1873 - CFG_FLASH_WRITE_TOUT:
1874 Timeout for Flash write operations (in ms)
1876 - CFG_FLASH_LOCK_TOUT
1877 Timeout for Flash set sector lock bit operation (in ms)
1879 - CFG_FLASH_UNLOCK_TOUT
1880 Timeout for Flash clear lock bits operation (in ms)
1882 - CFG_FLASH_PROTECTION
1883 If defined, hardware flash sectors protection is used
1884 instead of U-Boot software protection.
1886 - CFG_DIRECT_FLASH_TFTP:
1888 Enable TFTP transfers directly to flash memory;
1889 without this option such a download has to be
1890 performed in two steps: (1) download to RAM, and (2)
1891 copy from RAM to flash.
1893 The two-step approach is usually more reliable, since
1894 you can check if the download worked before you erase
1895 the flash, but in some situations (when sytem RAM is
1896 too limited to allow for a tempory copy of the
1897 downloaded image) this option may be very useful.
1900 Define if the flash driver uses extra elements in the
1901 common flash structure for storing flash geometry.
1903 - CFG_FLASH_CFI_DRIVER
1904 This option also enables the building of the cfi_flash driver
1905 in the drivers directory
1907 - CFG_FLASH_QUIET_TEST
1908 If this option is defined, the common CFI flash doesn't
1909 print it's warning upon not recognized FLASH banks. This
1910 is useful, if some of the configured banks are only
1911 optionally available.
1913 - CFG_RX_ETH_BUFFER:
1914 Defines the number of ethernet receive buffers. On some
1915 ethernet controllers it is recommended to set this value
1916 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1917 buffers can be full shortly after enabling the interface
1918 on high ethernet traffic.
1919 Defaults to 4 if not defined.
1921 The following definitions that deal with the placement and management
1922 of environment data (variable area); in general, we support the
1923 following configurations:
1925 - CFG_ENV_IS_IN_FLASH:
1927 Define this if the environment is in flash memory.
1929 a) The environment occupies one whole flash sector, which is
1930 "embedded" in the text segment with the U-Boot code. This
1931 happens usually with "bottom boot sector" or "top boot
1932 sector" type flash chips, which have several smaller
1933 sectors at the start or the end. For instance, such a
1934 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1935 such a case you would place the environment in one of the
1936 4 kB sectors - with U-Boot code before and after it. With
1937 "top boot sector" type flash chips, you would put the
1938 environment in one of the last sectors, leaving a gap
1939 between U-Boot and the environment.
1943 Offset of environment data (variable area) to the
1944 beginning of flash memory; for instance, with bottom boot
1945 type flash chips the second sector can be used: the offset
1946 for this sector is given here.
1948 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1952 This is just another way to specify the start address of
1953 the flash sector containing the environment (instead of
1956 - CFG_ENV_SECT_SIZE:
1958 Size of the sector containing the environment.
1961 b) Sometimes flash chips have few, equal sized, BIG sectors.
1962 In such a case you don't want to spend a whole sector for
1967 If you use this in combination with CFG_ENV_IS_IN_FLASH
1968 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1969 of this flash sector for the environment. This saves
1970 memory for the RAM copy of the environment.
1972 It may also save flash memory if you decide to use this
1973 when your environment is "embedded" within U-Boot code,
1974 since then the remainder of the flash sector could be used
1975 for U-Boot code. It should be pointed out that this is
1976 STRONGLY DISCOURAGED from a robustness point of view:
1977 updating the environment in flash makes it always
1978 necessary to erase the WHOLE sector. If something goes
1979 wrong before the contents has been restored from a copy in
1980 RAM, your target system will be dead.
1982 - CFG_ENV_ADDR_REDUND
1985 These settings describe a second storage area used to hold
1986 a redundand copy of the environment data, so that there is
1987 a valid backup copy in case there is a power failure during
1988 a "saveenv" operation.
1990 BE CAREFUL! Any changes to the flash layout, and some changes to the
1991 source code will make it necessary to adapt <board>/u-boot.lds*
1995 - CFG_ENV_IS_IN_NVRAM:
1997 Define this if you have some non-volatile memory device
1998 (NVRAM, battery buffered SRAM) which you want to use for the
2004 These two #defines are used to determin the memory area you
2005 want to use for environment. It is assumed that this memory
2006 can just be read and written to, without any special
2009 BE CAREFUL! The first access to the environment happens quite early
2010 in U-Boot initalization (when we try to get the setting of for the
2011 console baudrate). You *MUST* have mappend your NVRAM area then, or
2014 Please note that even with NVRAM we still use a copy of the
2015 environment in RAM: we could work on NVRAM directly, but we want to
2016 keep settings there always unmodified except somebody uses "saveenv"
2017 to save the current settings.
2020 - CFG_ENV_IS_IN_EEPROM:
2022 Use this if you have an EEPROM or similar serial access
2023 device and a driver for it.
2028 These two #defines specify the offset and size of the
2029 environment area within the total memory of your EEPROM.
2031 - CFG_I2C_EEPROM_ADDR:
2032 If defined, specified the chip address of the EEPROM device.
2033 The default address is zero.
2035 - CFG_EEPROM_PAGE_WRITE_BITS:
2036 If defined, the number of bits used to address bytes in a
2037 single page in the EEPROM device. A 64 byte page, for example
2038 would require six bits.
2040 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2041 If defined, the number of milliseconds to delay between
2042 page writes. The default is zero milliseconds.
2044 - CFG_I2C_EEPROM_ADDR_LEN:
2045 The length in bytes of the EEPROM memory array address. Note
2046 that this is NOT the chip address length!
2048 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2049 EEPROM chips that implement "address overflow" are ones
2050 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2051 address and the extra bits end up in the "chip address" bit
2052 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2055 Note that we consider the length of the address field to
2056 still be one byte because the extra address bits are hidden
2057 in the chip address.
2060 The size in bytes of the EEPROM device.
2063 - CFG_ENV_IS_IN_DATAFLASH:
2065 Define this if you have a DataFlash memory device which you
2066 want to use for the environment.
2072 These three #defines specify the offset and size of the
2073 environment area within the total memory of your DataFlash placed
2074 at the specified address.
2076 - CFG_ENV_IS_IN_NAND:
2078 Define this if you have a NAND device which you want to use
2079 for the environment.
2084 These two #defines specify the offset and size of the environment
2085 area within the first NAND device.
2087 - CFG_ENV_OFFSET_REDUND
2089 This setting describes a second storage area of CFG_ENV_SIZE
2090 size used to hold a redundant copy of the environment data,
2091 so that there is a valid backup copy in case there is a
2092 power failure during a "saveenv" operation.
2094 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2095 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2096 the NAND devices block size.
2098 - CFG_SPI_INIT_OFFSET
2100 Defines offset to the initial SPI buffer area in DPRAM. The
2101 area is used at an early stage (ROM part) if the environment
2102 is configured to reside in the SPI EEPROM: We need a 520 byte
2103 scratch DPRAM area. It is used between the two initialization
2104 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2105 to be a good choice since it makes it far enough from the
2106 start of the data area as well as from the stack pointer.
2108 Please note that the environment is read-only as long as the monitor
2109 has been relocated to RAM and a RAM copy of the environment has been
2110 created; also, when using EEPROM you will have to use getenv_r()
2111 until then to read environment variables.
2113 The environment is protected by a CRC32 checksum. Before the monitor
2114 is relocated into RAM, as a result of a bad CRC you will be working
2115 with the compiled-in default environment - *silently*!!! [This is
2116 necessary, because the first environment variable we need is the
2117 "baudrate" setting for the console - if we have a bad CRC, we don't
2118 have any device yet where we could complain.]
2120 Note: once the monitor has been relocated, then it will complain if
2121 the default environment is used; a new CRC is computed as soon as you
2122 use the "saveenv" command to store a valid environment.
2124 - CFG_FAULT_ECHO_LINK_DOWN:
2125 Echo the inverted Ethernet link state to the fault LED.
2127 Note: If this option is active, then CFG_FAULT_MII_ADDR
2128 also needs to be defined.
2130 - CFG_FAULT_MII_ADDR:
2131 MII address of the PHY to check for the Ethernet link state.
2133 - CFG_64BIT_VSPRINTF:
2134 Makes vsprintf (and all *printf functions) support printing
2135 of 64bit values by using the L quantifier
2137 - CFG_64BIT_STRTOUL:
2138 Adds simple_strtoull that returns a 64bit value
2140 Low Level (hardware related) configuration options:
2141 ---------------------------------------------------
2143 - CFG_CACHELINE_SIZE:
2144 Cache Line Size of the CPU.
2147 Default address of the IMMR after system reset.
2149 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2150 and RPXsuper) to be able to adjust the position of
2151 the IMMR register after a reset.
2153 - Floppy Disk Support:
2154 CFG_FDC_DRIVE_NUMBER
2156 the default drive number (default value 0)
2160 defines the spacing between fdc chipset registers
2165 defines the offset of register from address. It
2166 depends on which part of the data bus is connected to
2167 the fdc chipset. (default value 0)
2169 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2170 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2173 if CFG_FDC_HW_INIT is defined, then the function
2174 fdc_hw_init() is called at the beginning of the FDC
2175 setup. fdc_hw_init() must be provided by the board
2176 source code. It is used to make hardware dependant
2179 - CFG_IMMR: Physical address of the Internal Memory.
2180 DO NOT CHANGE unless you know exactly what you're
2181 doing! (11-4) [MPC8xx/82xx systems only]
2183 - CFG_INIT_RAM_ADDR:
2185 Start address of memory area that can be used for
2186 initial data and stack; please note that this must be
2187 writable memory that is working WITHOUT special
2188 initialization, i. e. you CANNOT use normal RAM which
2189 will become available only after programming the
2190 memory controller and running certain initialization
2193 U-Boot uses the following memory types:
2194 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2195 - MPC824X: data cache
2196 - PPC4xx: data cache
2198 - CFG_GBL_DATA_OFFSET:
2200 Offset of the initial data structure in the memory
2201 area defined by CFG_INIT_RAM_ADDR. Usually
2202 CFG_GBL_DATA_OFFSET is chosen such that the initial
2203 data is located at the end of the available space
2204 (sometimes written as (CFG_INIT_RAM_END -
2205 CFG_INIT_DATA_SIZE), and the initial stack is just
2206 below that area (growing from (CFG_INIT_RAM_ADDR +
2207 CFG_GBL_DATA_OFFSET) downward.
2210 On the MPC824X (or other systems that use the data
2211 cache for initial memory) the address chosen for
2212 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2213 point to an otherwise UNUSED address space between
2214 the top of RAM and the start of the PCI space.
2216 - CFG_SIUMCR: SIU Module Configuration (11-6)
2218 - CFG_SYPCR: System Protection Control (11-9)
2220 - CFG_TBSCR: Time Base Status and Control (11-26)
2222 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2224 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2226 - CFG_SCCR: System Clock and reset Control Register (15-27)
2228 - CFG_OR_TIMING_SDRAM:
2232 periodic timer for refresh
2234 - CFG_DER: Debug Event Register (37-47)
2236 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2237 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2238 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2240 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2242 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2243 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2244 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2245 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2247 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2248 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2249 Machine Mode Register and Memory Periodic Timer
2250 Prescaler definitions (SDRAM timing)
2252 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2253 enable I2C microcode relocation patch (MPC8xx);
2254 define relocation offset in DPRAM [DSP2]
2256 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2257 enable SPI microcode relocation patch (MPC8xx);
2258 define relocation offset in DPRAM [SCC4]
2261 Use OSCM clock mode on MBX8xx board. Be careful,
2262 wrong setting might damage your board. Read
2263 doc/README.MBX before setting this variable!
2265 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2266 Offset of the bootmode word in DPRAM used by post
2267 (Power On Self Tests). This definition overrides
2268 #define'd default value in commproc.h resp.
2271 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2272 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2273 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2274 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2275 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2276 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2277 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2278 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2279 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2282 Get DDR timing information from an I2C EEPROM. Common with pluggable
2283 memory modules such as SODIMMs
2285 I2C address of the SPD EEPROM
2288 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2289 Note that the value must resolve to something your driver can deal with.
2291 - CFG_83XX_DDR_USES_CS0
2292 Only for 83xx systems. If specified, then DDR should be configured
2293 using CS0 and CS1 instead of CS2 and CS3.
2295 - CFG_83XX_DDR_USES_CS0
2296 Only for 83xx systems. If specified, then DDR should be configured
2297 using CS0 and CS1 instead of CS2 and CS3.
2299 - CONFIG_ETHER_ON_FEC[12]
2300 Define to enable FEC[12] on a 8xx series processor.
2302 - CONFIG_FEC[12]_PHY
2303 Define to the hardcoded PHY address which corresponds
2304 to the given FEC; i. e.
2305 #define CONFIG_FEC1_PHY 4
2306 means that the PHY with address 4 is connected to FEC1
2308 When set to -1, means to probe for first available.
2310 - CONFIG_FEC[12]_PHY_NORXERR
2311 The PHY does not have a RXERR line (RMII only).
2312 (so program the FEC to ignore it).
2315 Enable RMII mode for all FECs.
2316 Note that this is a global option, we can't
2317 have one FEC in standard MII mode and another in RMII mode.
2319 - CONFIG_CRC32_VERIFY
2320 Add a verify option to the crc32 command.
2323 => crc32 -v <address> <count> <crc32>
2325 Where address/count indicate a memory area
2326 and crc32 is the correct crc32 which the
2330 Add the "loopw" memory command. This only takes effect if
2331 the memory commands are activated globally (CFG_CMD_MEM).
2334 Add the "mdc" and "mwc" memory commands. These are cyclic
2339 This command will print 4 bytes (10,11,12,13) each 500 ms.
2341 => mwc.l 100 12345678 10
2342 This command will write 12345678 to address 100 all 10 ms.
2344 This only takes effect if the memory commands are activated
2345 globally (CFG_CMD_MEM).
2347 - CONFIG_SKIP_LOWLEVEL_INIT
2348 - CONFIG_SKIP_RELOCATE_UBOOT
2350 [ARM only] If these variables are defined, then
2351 certain low level initializations (like setting up
2352 the memory controller) are omitted and/or U-Boot does
2353 not relocate itself into RAM.
2354 Normally these variables MUST NOT be defined. The
2355 only exception is when U-Boot is loaded (to RAM) by
2356 some other boot loader or by a debugger which
2357 performs these intializations itself.
2360 Building the Software:
2361 ======================
2363 Building U-Boot has been tested in native PPC environments (on a
2364 PowerBook G3 running LinuxPPC 2000) and in cross environments
2365 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2368 If you are not using a native PPC environment, it is assumed that you
2369 have the GNU cross compiling tools available in your path and named
2370 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2371 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2372 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2375 CROSS_COMPILE = ppc_4xx-
2378 U-Boot is intended to be simple to build. After installing the
2379 sources you must configure U-Boot for one specific board type. This
2384 where "NAME_config" is the name of one of the existing
2385 configurations; the following names are supported:
2387 ADCIOP_config FPS860L_config omap730p2_config
2388 ADS860_config GEN860T_config pcu_e_config
2390 AR405_config GENIETV_config PIP405_config
2391 at91rm9200dk_config GTH_config QS823_config
2392 CANBT_config hermes_config QS850_config
2393 cmi_mpc5xx_config hymod_config QS860T_config
2394 cogent_common_config IP860_config RPXlite_config
2395 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2396 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2397 CPCI405_config JSE_config rsdproto_config
2398 CPCIISER4_config LANTEC_config Sandpoint8240_config
2399 csb272_config lwmon_config sbc8260_config
2400 CU824_config MBX860T_config sbc8560_33_config
2401 DUET_ADS_config MBX_config sbc8560_66_config
2402 EBONY_config mpc7448hpc2_config SM850_config
2403 ELPT860_config MPC8260ADS_config SPD823TS_config
2404 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2405 ETX094_config MPC8540EVAL_config SXNI855T_config
2406 FADS823_config NMPC8560ADS_config TQM823L_config
2407 FADS850SAR_config NETVIA_config TQM850L_config
2408 FADS860T_config omap1510inn_config TQM855L_config
2409 FPS850L_config omap1610h2_config TQM860L_config
2410 omap1610inn_config walnut_config
2411 omap5912osk_config Yukon8220_config
2412 omap2420h4_config ZPC1900_config
2414 Note: for some board special configuration names may exist; check if
2415 additional information is available from the board vendor; for
2416 instance, the TQM823L systems are available without (standard)
2417 or with LCD support. You can select such additional "features"
2418 when chosing the configuration, i. e.
2421 - will configure for a plain TQM823L, i. e. no LCD support
2423 make TQM823L_LCD_config
2424 - will configure for a TQM823L with U-Boot console on LCD
2429 Finally, type "make all", and you should get some working U-Boot
2430 images ready for download to / installation on your system:
2432 - "u-boot.bin" is a raw binary image
2433 - "u-boot" is an image in ELF binary format
2434 - "u-boot.srec" is in Motorola S-Record format
2436 By default the build is performed locally and the objects are saved
2437 in the source directory. One of the two methods can be used to change
2438 this behavior and build U-Boot to some external directory:
2440 1. Add O= to the make command line invocations:
2442 make O=/tmp/build distclean
2443 make O=/tmp/build NAME_config
2444 make O=/tmp/build all
2446 2. Set environment variable BUILD_DIR to point to the desired location:
2448 export BUILD_DIR=/tmp/build
2453 Note that the command line "O=" setting overrides the BUILD_DIR environment
2457 Please be aware that the Makefiles assume you are using GNU make, so
2458 for instance on NetBSD you might need to use "gmake" instead of
2462 If the system board that you have is not listed, then you will need
2463 to port U-Boot to your hardware platform. To do this, follow these
2466 1. Add a new configuration option for your board to the toplevel
2467 "Makefile" and to the "MAKEALL" script, using the existing
2468 entries as examples. Note that here and at many other places
2469 boards and other names are listed in alphabetical sort order. Please
2471 2. Create a new directory to hold your board specific code. Add any
2472 files you need. In your board directory, you will need at least
2473 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2474 3. Create a new configuration file "include/configs/<board>.h" for
2476 3. If you're porting U-Boot to a new CPU, then also create a new
2477 directory to hold your CPU specific code. Add any files you need.
2478 4. Run "make <board>_config" with your new name.
2479 5. Type "make", and you should get a working "u-boot.srec" file
2480 to be installed on your target system.
2481 6. Debug and solve any problems that might arise.
2482 [Of course, this last step is much harder than it sounds.]
2485 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2486 ==============================================================
2488 If you have modified U-Boot sources (for instance added a new board
2489 or support for new devices, a new CPU, etc.) you are expected to
2490 provide feedback to the other developers. The feedback normally takes
2491 the form of a "patch", i. e. a context diff against a certain (latest
2492 official or latest in CVS) version of U-Boot sources.
2494 But before you submit such a patch, please verify that your modifi-
2495 cation did not break existing code. At least make sure that *ALL* of
2496 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2497 just run the "MAKEALL" script, which will configure and build U-Boot
2498 for ALL supported system. Be warned, this will take a while. You can
2499 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2500 environment variable to the script, i. e. to use the cross tools from
2501 MontaVista's Hard Hat Linux you can type
2503 CROSS_COMPILE=ppc_8xx- MAKEALL
2505 or to build on a native PowerPC system you can type
2507 CROSS_COMPILE=' ' MAKEALL
2509 When using the MAKEALL script, the default behaviour is to build U-Boot
2510 in the source directory. This location can be changed by setting the
2511 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2512 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2513 <source dir>/LOG directory. This default location can be changed by
2514 setting the MAKEALL_LOGDIR environment variable. For example:
2516 export BUILD_DIR=/tmp/build
2517 export MAKEALL_LOGDIR=/tmp/log
2518 CROSS_COMPILE=ppc_8xx- MAKEALL
2520 With the above settings build objects are saved in the /tmp/build, log
2521 files are saved in the /tmp/log and the source tree remains clean during
2522 the whole build process.
2525 See also "U-Boot Porting Guide" below.
2528 Monitor Commands - Overview:
2529 ============================
2531 go - start application at address 'addr'
2532 run - run commands in an environment variable
2533 bootm - boot application image from memory
2534 bootp - boot image via network using BootP/TFTP protocol
2535 tftpboot- boot image via network using TFTP protocol
2536 and env variables "ipaddr" and "serverip"
2537 (and eventually "gatewayip")
2538 rarpboot- boot image via network using RARP/TFTP protocol
2539 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2540 loads - load S-Record file over serial line
2541 loadb - load binary file over serial line (kermit mode)
2543 mm - memory modify (auto-incrementing)
2544 nm - memory modify (constant address)
2545 mw - memory write (fill)
2547 cmp - memory compare
2548 crc32 - checksum calculation
2549 imd - i2c memory display
2550 imm - i2c memory modify (auto-incrementing)
2551 inm - i2c memory modify (constant address)
2552 imw - i2c memory write (fill)
2553 icrc32 - i2c checksum calculation
2554 iprobe - probe to discover valid I2C chip addresses
2555 iloop - infinite loop on address range
2556 isdram - print SDRAM configuration information
2557 sspi - SPI utility commands
2558 base - print or set address offset
2559 printenv- print environment variables
2560 setenv - set environment variables
2561 saveenv - save environment variables to persistent storage
2562 protect - enable or disable FLASH write protection
2563 erase - erase FLASH memory
2564 flinfo - print FLASH memory information
2565 bdinfo - print Board Info structure
2566 iminfo - print header information for application image
2567 coninfo - print console devices and informations
2568 ide - IDE sub-system
2569 loop - infinite loop on address range
2570 loopw - infinite write loop on address range
2571 mtest - simple RAM test
2572 icache - enable or disable instruction cache
2573 dcache - enable or disable data cache
2574 reset - Perform RESET of the CPU
2575 echo - echo args to console
2576 version - print monitor version
2577 help - print online help
2578 ? - alias for 'help'
2581 Monitor Commands - Detailed Description:
2582 ========================================
2586 For now: just type "help <command>".
2589 Environment Variables:
2590 ======================
2592 U-Boot supports user configuration using Environment Variables which
2593 can be made persistent by saving to Flash memory.
2595 Environment Variables are set using "setenv", printed using
2596 "printenv", and saved to Flash using "saveenv". Using "setenv"
2597 without a value can be used to delete a variable from the
2598 environment. As long as you don't save the environment you are
2599 working with an in-memory copy. In case the Flash area containing the
2600 environment is erased by accident, a default environment is provided.
2602 Some configuration options can be set using Environment Variables:
2604 baudrate - see CONFIG_BAUDRATE
2606 bootdelay - see CONFIG_BOOTDELAY
2608 bootcmd - see CONFIG_BOOTCOMMAND
2610 bootargs - Boot arguments when booting an RTOS image
2612 bootfile - Name of the image to load with TFTP
2614 autoload - if set to "no" (any string beginning with 'n'),
2615 "bootp" will just load perform a lookup of the
2616 configuration from the BOOTP server, but not try to
2617 load any image using TFTP
2619 autostart - if set to "yes", an image loaded using the "bootp",
2620 "rarpboot", "tftpboot" or "diskboot" commands will
2621 be automatically started (by internally calling
2624 If set to "no", a standalone image passed to the
2625 "bootm" command will be copied to the load address
2626 (and eventually uncompressed), but NOT be started.
2627 This can be used to load and uncompress arbitrary
2630 i2cfast - (PPC405GP|PPC405EP only)
2631 if set to 'y' configures Linux I2C driver for fast
2632 mode (400kHZ). This environment variable is used in
2633 initialization code. So, for changes to be effective
2634 it must be saved and board must be reset.
2636 initrd_high - restrict positioning of initrd images:
2637 If this variable is not set, initrd images will be
2638 copied to the highest possible address in RAM; this
2639 is usually what you want since it allows for
2640 maximum initrd size. If for some reason you want to
2641 make sure that the initrd image is loaded below the
2642 CFG_BOOTMAPSZ limit, you can set this environment
2643 variable to a value of "no" or "off" or "0".
2644 Alternatively, you can set it to a maximum upper
2645 address to use (U-Boot will still check that it
2646 does not overwrite the U-Boot stack and data).
2648 For instance, when you have a system with 16 MB
2649 RAM, and want to reserve 4 MB from use by Linux,
2650 you can do this by adding "mem=12M" to the value of
2651 the "bootargs" variable. However, now you must make
2652 sure that the initrd image is placed in the first
2653 12 MB as well - this can be done with
2655 setenv initrd_high 00c00000
2657 If you set initrd_high to 0xFFFFFFFF, this is an
2658 indication to U-Boot that all addresses are legal
2659 for the Linux kernel, including addresses in flash
2660 memory. In this case U-Boot will NOT COPY the
2661 ramdisk at all. This may be useful to reduce the
2662 boot time on your system, but requires that this
2663 feature is supported by your Linux kernel.
2665 ipaddr - IP address; needed for tftpboot command
2667 loadaddr - Default load address for commands like "bootp",
2668 "rarpboot", "tftpboot", "loadb" or "diskboot"
2670 loads_echo - see CONFIG_LOADS_ECHO
2672 serverip - TFTP server IP address; needed for tftpboot command
2674 bootretry - see CONFIG_BOOT_RETRY_TIME
2676 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2678 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2680 ethprime - When CONFIG_NET_MULTI is enabled controls which
2681 interface is used first.
2683 ethact - When CONFIG_NET_MULTI is enabled controls which
2684 interface is currently active. For example you
2685 can do the following
2687 => setenv ethact FEC ETHERNET
2688 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2689 => setenv ethact SCC ETHERNET
2690 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2692 netretry - When set to "no" each network operation will
2693 either succeed or fail without retrying.
2694 When set to "once" the network operation will
2695 fail when all the available network interfaces
2696 are tried once without success.
2697 Useful on scripts which control the retry operation
2700 tftpsrcport - If this is set, the value is used for TFTP's
2703 tftpdstport - If this is set, the value is used for TFTP's UDP
2704 destination port instead of the Well Know Port 69.
2706 vlan - When set to a value < 4095 the traffic over
2707 ethernet is encapsulated/received over 802.1q
2710 The following environment variables may be used and automatically
2711 updated by the network boot commands ("bootp" and "rarpboot"),
2712 depending the information provided by your boot server:
2714 bootfile - see above
2715 dnsip - IP address of your Domain Name Server
2716 dnsip2 - IP address of your secondary Domain Name Server
2717 gatewayip - IP address of the Gateway (Router) to use
2718 hostname - Target hostname
2720 netmask - Subnet Mask
2721 rootpath - Pathname of the root filesystem on the NFS server
2722 serverip - see above
2725 There are two special Environment Variables:
2727 serial# - contains hardware identification information such
2728 as type string and/or serial number
2729 ethaddr - Ethernet address
2731 These variables can be set only once (usually during manufacturing of
2732 the board). U-Boot refuses to delete or overwrite these variables
2733 once they have been set once.
2736 Further special Environment Variables:
2738 ver - Contains the U-Boot version string as printed
2739 with the "version" command. This variable is
2740 readonly (see CONFIG_VERSION_VARIABLE).
2743 Please note that changes to some configuration parameters may take
2744 only effect after the next boot (yes, that's just like Windoze :-).
2747 Command Line Parsing:
2748 =====================
2750 There are two different command line parsers available with U-Boot:
2751 the old "simple" one, and the much more powerful "hush" shell:
2753 Old, simple command line parser:
2754 --------------------------------
2756 - supports environment variables (through setenv / saveenv commands)
2757 - several commands on one line, separated by ';'
2758 - variable substitution using "... ${name} ..." syntax
2759 - special characters ('$', ';') can be escaped by prefixing with '\',
2761 setenv bootcmd bootm \${address}
2762 - You can also escape text by enclosing in single apostrophes, for example:
2763 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2768 - similar to Bourne shell, with control structures like
2769 if...then...else...fi, for...do...done; while...do...done,
2770 until...do...done, ...
2771 - supports environment ("global") variables (through setenv / saveenv
2772 commands) and local shell variables (through standard shell syntax
2773 "name=value"); only environment variables can be used with "run"
2779 (1) If a command line (or an environment variable executed by a "run"
2780 command) contains several commands separated by semicolon, and
2781 one of these commands fails, then the remaining commands will be
2784 (2) If you execute several variables with one call to run (i. e.
2785 calling run with a list af variables as arguments), any failing
2786 command will cause "run" to terminate, i. e. the remaining
2787 variables are not executed.
2789 Note for Redundant Ethernet Interfaces:
2790 =======================================
2792 Some boards come with redundant ethernet interfaces; U-Boot supports
2793 such configurations and is capable of automatic selection of a
2794 "working" interface when needed. MAC assignment works as follows:
2796 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2797 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2798 "eth1addr" (=>eth1), "eth2addr", ...
2800 If the network interface stores some valid MAC address (for instance
2801 in SROM), this is used as default address if there is NO correspon-
2802 ding setting in the environment; if the corresponding environment
2803 variable is set, this overrides the settings in the card; that means:
2805 o If the SROM has a valid MAC address, and there is no address in the
2806 environment, the SROM's address is used.
2808 o If there is no valid address in the SROM, and a definition in the
2809 environment exists, then the value from the environment variable is
2812 o If both the SROM and the environment contain a MAC address, and
2813 both addresses are the same, this MAC address is used.
2815 o If both the SROM and the environment contain a MAC address, and the
2816 addresses differ, the value from the environment is used and a
2819 o If neither SROM nor the environment contain a MAC address, an error
2826 The "boot" commands of this monitor operate on "image" files which
2827 can be basicly anything, preceeded by a special header; see the
2828 definitions in include/image.h for details; basicly, the header
2829 defines the following image properties:
2831 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2832 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2833 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2834 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2835 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2836 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2837 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2838 * Compression Type (uncompressed, gzip, bzip2)
2844 The header is marked by a special Magic Number, and both the header
2845 and the data portions of the image are secured against corruption by
2852 Although U-Boot should support any OS or standalone application
2853 easily, the main focus has always been on Linux during the design of
2856 U-Boot includes many features that so far have been part of some
2857 special "boot loader" code within the Linux kernel. Also, any
2858 "initrd" images to be used are no longer part of one big Linux image;
2859 instead, kernel and "initrd" are separate images. This implementation
2860 serves several purposes:
2862 - the same features can be used for other OS or standalone
2863 applications (for instance: using compressed images to reduce the
2864 Flash memory footprint)
2866 - it becomes much easier to port new Linux kernel versions because
2867 lots of low-level, hardware dependent stuff are done by U-Boot
2869 - the same Linux kernel image can now be used with different "initrd"
2870 images; of course this also means that different kernel images can
2871 be run with the same "initrd". This makes testing easier (you don't
2872 have to build a new "zImage.initrd" Linux image when you just
2873 change a file in your "initrd"). Also, a field-upgrade of the
2874 software is easier now.
2880 Porting Linux to U-Boot based systems:
2881 ---------------------------------------
2883 U-Boot cannot save you from doing all the necessary modifications to
2884 configure the Linux device drivers for use with your target hardware
2885 (no, we don't intend to provide a full virtual machine interface to
2888 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2890 Just make sure your machine specific header file (for instance
2891 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2892 Information structure as we define in include/u-boot.h, and make
2893 sure that your definition of IMAP_ADDR uses the same value as your
2894 U-Boot configuration in CFG_IMMR.
2897 Configuring the Linux kernel:
2898 -----------------------------
2900 No specific requirements for U-Boot. Make sure you have some root
2901 device (initial ramdisk, NFS) for your target system.
2904 Building a Linux Image:
2905 -----------------------
2907 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2908 not used. If you use recent kernel source, a new build target
2909 "uImage" will exist which automatically builds an image usable by
2910 U-Boot. Most older kernels also have support for a "pImage" target,
2911 which was introduced for our predecessor project PPCBoot and uses a
2912 100% compatible format.
2921 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2922 encapsulate a compressed Linux kernel image with header information,
2923 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2925 * build a standard "vmlinux" kernel image (in ELF binary format):
2927 * convert the kernel into a raw binary image:
2929 ${CROSS_COMPILE}-objcopy -O binary \
2930 -R .note -R .comment \
2931 -S vmlinux linux.bin
2933 * compress the binary image:
2937 * package compressed binary image for U-Boot:
2939 mkimage -A ppc -O linux -T kernel -C gzip \
2940 -a 0 -e 0 -n "Linux Kernel Image" \
2941 -d linux.bin.gz uImage
2944 The "mkimage" tool can also be used to create ramdisk images for use
2945 with U-Boot, either separated from the Linux kernel image, or
2946 combined into one file. "mkimage" encapsulates the images with a 64
2947 byte header containing information about target architecture,
2948 operating system, image type, compression method, entry points, time
2949 stamp, CRC32 checksums, etc.
2951 "mkimage" can be called in two ways: to verify existing images and
2952 print the header information, or to build new images.
2954 In the first form (with "-l" option) mkimage lists the information
2955 contained in the header of an existing U-Boot image; this includes
2956 checksum verification:
2958 tools/mkimage -l image
2959 -l ==> list image header information
2961 The second form (with "-d" option) is used to build a U-Boot image
2962 from a "data file" which is used as image payload:
2964 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2965 -n name -d data_file image
2966 -A ==> set architecture to 'arch'
2967 -O ==> set operating system to 'os'
2968 -T ==> set image type to 'type'
2969 -C ==> set compression type 'comp'
2970 -a ==> set load address to 'addr' (hex)
2971 -e ==> set entry point to 'ep' (hex)
2972 -n ==> set image name to 'name'
2973 -d ==> use image data from 'datafile'
2975 Right now, all Linux kernels for PowerPC systems use the same load
2976 address (0x00000000), but the entry point address depends on the
2979 - 2.2.x kernels have the entry point at 0x0000000C,
2980 - 2.3.x and later kernels have the entry point at 0x00000000.
2982 So a typical call to build a U-Boot image would read:
2984 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2985 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2986 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2987 > examples/uImage.TQM850L
2988 Image Name: 2.4.4 kernel for TQM850L
2989 Created: Wed Jul 19 02:34:59 2000
2990 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2991 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2992 Load Address: 0x00000000
2993 Entry Point: 0x00000000
2995 To verify the contents of the image (or check for corruption):
2997 -> tools/mkimage -l examples/uImage.TQM850L
2998 Image Name: 2.4.4 kernel for TQM850L
2999 Created: Wed Jul 19 02:34:59 2000
3000 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3001 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3002 Load Address: 0x00000000
3003 Entry Point: 0x00000000
3005 NOTE: for embedded systems where boot time is critical you can trade
3006 speed for memory and install an UNCOMPRESSED image instead: this
3007 needs more space in Flash, but boots much faster since it does not
3008 need to be uncompressed:
3010 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3011 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3012 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3013 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3014 > examples/uImage.TQM850L-uncompressed
3015 Image Name: 2.4.4 kernel for TQM850L
3016 Created: Wed Jul 19 02:34:59 2000
3017 Image Type: PowerPC Linux Kernel Image (uncompressed)
3018 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3019 Load Address: 0x00000000
3020 Entry Point: 0x00000000
3023 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3024 when your kernel is intended to use an initial ramdisk:
3026 -> tools/mkimage -n 'Simple Ramdisk Image' \
3027 > -A ppc -O linux -T ramdisk -C gzip \
3028 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3029 Image Name: Simple Ramdisk Image
3030 Created: Wed Jan 12 14:01:50 2000
3031 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3032 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3033 Load Address: 0x00000000
3034 Entry Point: 0x00000000
3037 Installing a Linux Image:
3038 -------------------------
3040 To downloading a U-Boot image over the serial (console) interface,
3041 you must convert the image to S-Record format:
3043 objcopy -I binary -O srec examples/image examples/image.srec
3045 The 'objcopy' does not understand the information in the U-Boot
3046 image header, so the resulting S-Record file will be relative to
3047 address 0x00000000. To load it to a given address, you need to
3048 specify the target address as 'offset' parameter with the 'loads'
3051 Example: install the image to address 0x40100000 (which on the
3052 TQM8xxL is in the first Flash bank):
3054 => erase 40100000 401FFFFF
3060 ## Ready for S-Record download ...
3061 ~>examples/image.srec
3062 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3064 15989 15990 15991 15992
3065 [file transfer complete]
3067 ## Start Addr = 0x00000000
3070 You can check the success of the download using the 'iminfo' command;
3071 this includes a checksum verification so you can be sure no data
3072 corruption happened:
3076 ## Checking Image at 40100000 ...
3077 Image Name: 2.2.13 for initrd on TQM850L
3078 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3079 Data Size: 335725 Bytes = 327 kB = 0 MB
3080 Load Address: 00000000
3081 Entry Point: 0000000c
3082 Verifying Checksum ... OK
3088 The "bootm" command is used to boot an application that is stored in
3089 memory (RAM or Flash). In case of a Linux kernel image, the contents
3090 of the "bootargs" environment variable is passed to the kernel as
3091 parameters. You can check and modify this variable using the
3092 "printenv" and "setenv" commands:
3095 => printenv bootargs
3096 bootargs=root=/dev/ram
3098 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3100 => printenv bootargs
3101 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3104 ## Booting Linux kernel at 40020000 ...
3105 Image Name: 2.2.13 for NFS on TQM850L
3106 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3107 Data Size: 381681 Bytes = 372 kB = 0 MB
3108 Load Address: 00000000
3109 Entry Point: 0000000c
3110 Verifying Checksum ... OK
3111 Uncompressing Kernel Image ... OK
3112 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
3113 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3114 time_init: decrementer frequency = 187500000/60
3115 Calibrating delay loop... 49.77 BogoMIPS
3116 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3119 If you want to boot a Linux kernel with initial ram disk, you pass
3120 the memory addresses of both the kernel and the initrd image (PPBCOOT
3121 format!) to the "bootm" command:
3123 => imi 40100000 40200000
3125 ## Checking Image at 40100000 ...
3126 Image Name: 2.2.13 for initrd on TQM850L
3127 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3128 Data Size: 335725 Bytes = 327 kB = 0 MB
3129 Load Address: 00000000
3130 Entry Point: 0000000c
3131 Verifying Checksum ... OK
3133 ## Checking Image at 40200000 ...
3134 Image Name: Simple Ramdisk Image
3135 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3136 Data Size: 566530 Bytes = 553 kB = 0 MB
3137 Load Address: 00000000
3138 Entry Point: 00000000
3139 Verifying Checksum ... OK
3141 => bootm 40100000 40200000
3142 ## Booting Linux kernel at 40100000 ...
3143 Image Name: 2.2.13 for initrd on TQM850L
3144 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3145 Data Size: 335725 Bytes = 327 kB = 0 MB
3146 Load Address: 00000000
3147 Entry Point: 0000000c
3148 Verifying Checksum ... OK
3149 Uncompressing Kernel Image ... OK
3150 ## Loading RAMDisk Image at 40200000 ...
3151 Image Name: Simple Ramdisk Image
3152 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3153 Data Size: 566530 Bytes = 553 kB = 0 MB
3154 Load Address: 00000000
3155 Entry Point: 00000000
3156 Verifying Checksum ... OK
3157 Loading Ramdisk ... OK
3158 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
3159 Boot arguments: root=/dev/ram
3160 time_init: decrementer frequency = 187500000/60
3161 Calibrating delay loop... 49.77 BogoMIPS
3163 RAMDISK: Compressed image found at block 0
3164 VFS: Mounted root (ext2 filesystem).
3168 Boot Linux and pass a flat device tree:
3171 First, U-Boot must be compiled with the appropriate defines. See the section
3172 titled "Linux Kernel Interface" above for a more in depth explanation. The
3173 following is an example of how to start a kernel and pass an updated
3179 oft=oftrees/mpc8540ads.dtb
3180 => tftp $oftaddr $oft
3181 Speed: 1000, full duplex
3183 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3184 Filename 'oftrees/mpc8540ads.dtb'.
3185 Load address: 0x300000
3188 Bytes transferred = 4106 (100a hex)
3189 => tftp $loadaddr $bootfile
3190 Speed: 1000, full duplex
3192 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3194 Load address: 0x200000
3195 Loading:############
3197 Bytes transferred = 1029407 (fb51f hex)
3202 => bootm $loadaddr - $oftaddr
3203 ## Booting image at 00200000 ...
3204 Image Name: Linux-2.6.17-dirty
3205 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3206 Data Size: 1029343 Bytes = 1005.2 kB
3207 Load Address: 00000000
3208 Entry Point: 00000000
3209 Verifying Checksum ... OK
3210 Uncompressing Kernel Image ... OK
3211 Booting using flat device tree at 0x300000
3212 Using MPC85xx ADS machine description
3213 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3217 More About U-Boot Image Types:
3218 ------------------------------
3220 U-Boot supports the following image types:
3222 "Standalone Programs" are directly runnable in the environment
3223 provided by U-Boot; it is expected that (if they behave
3224 well) you can continue to work in U-Boot after return from
3225 the Standalone Program.
3226 "OS Kernel Images" are usually images of some Embedded OS which
3227 will take over control completely. Usually these programs
3228 will install their own set of exception handlers, device
3229 drivers, set up the MMU, etc. - this means, that you cannot
3230 expect to re-enter U-Boot except by resetting the CPU.
3231 "RAMDisk Images" are more or less just data blocks, and their
3232 parameters (address, size) are passed to an OS kernel that is
3234 "Multi-File Images" contain several images, typically an OS
3235 (Linux) kernel image and one or more data images like
3236 RAMDisks. This construct is useful for instance when you want
3237 to boot over the network using BOOTP etc., where the boot
3238 server provides just a single image file, but you want to get
3239 for instance an OS kernel and a RAMDisk image.
3241 "Multi-File Images" start with a list of image sizes, each
3242 image size (in bytes) specified by an "uint32_t" in network
3243 byte order. This list is terminated by an "(uint32_t)0".
3244 Immediately after the terminating 0 follow the images, one by
3245 one, all aligned on "uint32_t" boundaries (size rounded up to
3246 a multiple of 4 bytes).
3248 "Firmware Images" are binary images containing firmware (like
3249 U-Boot or FPGA images) which usually will be programmed to
3252 "Script files" are command sequences that will be executed by
3253 U-Boot's command interpreter; this feature is especially
3254 useful when you configure U-Boot to use a real shell (hush)
3255 as command interpreter.
3261 One of the features of U-Boot is that you can dynamically load and
3262 run "standalone" applications, which can use some resources of
3263 U-Boot like console I/O functions or interrupt services.
3265 Two simple examples are included with the sources:
3270 'examples/hello_world.c' contains a small "Hello World" Demo
3271 application; it is automatically compiled when you build U-Boot.
3272 It's configured to run at address 0x00040004, so you can play with it
3276 ## Ready for S-Record download ...
3277 ~>examples/hello_world.srec
3278 1 2 3 4 5 6 7 8 9 10 11 ...
3279 [file transfer complete]
3281 ## Start Addr = 0x00040004
3283 => go 40004 Hello World! This is a test.
3284 ## Starting application at 0x00040004 ...
3295 Hit any key to exit ...
3297 ## Application terminated, rc = 0x0
3299 Another example, which demonstrates how to register a CPM interrupt
3300 handler with the U-Boot code, can be found in 'examples/timer.c'.
3301 Here, a CPM timer is set up to generate an interrupt every second.
3302 The interrupt service routine is trivial, just printing a '.'
3303 character, but this is just a demo program. The application can be
3304 controlled by the following keys:
3306 ? - print current values og the CPM Timer registers
3307 b - enable interrupts and start timer
3308 e - stop timer and disable interrupts
3309 q - quit application
3312 ## Ready for S-Record download ...
3313 ~>examples/timer.srec
3314 1 2 3 4 5 6 7 8 9 10 11 ...
3315 [file transfer complete]
3317 ## Start Addr = 0x00040004
3320 ## Starting application at 0x00040004 ...
3323 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3326 [q, b, e, ?] Set interval 1000000 us
3329 [q, b, e, ?] ........
3330 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3333 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3336 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3339 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3341 [q, b, e, ?] ...Stopping timer
3343 [q, b, e, ?] ## Application terminated, rc = 0x0
3349 Over time, many people have reported problems when trying to use the
3350 "minicom" terminal emulation program for serial download. I (wd)
3351 consider minicom to be broken, and recommend not to use it. Under
3352 Unix, I recommend to use C-Kermit for general purpose use (and
3353 especially for kermit binary protocol download ("loadb" command), and
3354 use "cu" for S-Record download ("loads" command).
3356 Nevertheless, if you absolutely want to use it try adding this
3357 configuration to your "File transfer protocols" section:
3359 Name Program Name U/D FullScr IO-Red. Multi
3360 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3361 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3367 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3368 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3370 Building requires a cross environment; it is known to work on
3371 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3372 need gmake since the Makefiles are not compatible with BSD make).
3373 Note that the cross-powerpc package does not install include files;
3374 attempting to build U-Boot will fail because <machine/ansi.h> is
3375 missing. This file has to be installed and patched manually:
3377 # cd /usr/pkg/cross/powerpc-netbsd/include
3379 # ln -s powerpc machine
3380 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3381 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3383 Native builds *don't* work due to incompatibilities between native
3384 and U-Boot include files.
3386 Booting assumes that (the first part of) the image booted is a
3387 stage-2 loader which in turn loads and then invokes the kernel
3388 proper. Loader sources will eventually appear in the NetBSD source
3389 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3390 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3393 Implementation Internals:
3394 =========================
3396 The following is not intended to be a complete description of every
3397 implementation detail. However, it should help to understand the
3398 inner workings of U-Boot and make it easier to port it to custom
3402 Initial Stack, Global Data:
3403 ---------------------------
3405 The implementation of U-Boot is complicated by the fact that U-Boot
3406 starts running out of ROM (flash memory), usually without access to
3407 system RAM (because the memory controller is not initialized yet).
3408 This means that we don't have writable Data or BSS segments, and BSS
3409 is not initialized as zero. To be able to get a C environment working
3410 at all, we have to allocate at least a minimal stack. Implementation
3411 options for this are defined and restricted by the CPU used: Some CPU
3412 models provide on-chip memory (like the IMMR area on MPC8xx and
3413 MPC826x processors), on others (parts of) the data cache can be
3414 locked as (mis-) used as memory, etc.
3416 Chris Hallinan posted a good summary of these issues to the
3417 u-boot-users mailing list:
3419 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3420 From: "Chris Hallinan" <clh@net1plus.com>
3421 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3424 Correct me if I'm wrong, folks, but the way I understand it
3425 is this: Using DCACHE as initial RAM for Stack, etc, does not
3426 require any physical RAM backing up the cache. The cleverness
3427 is that the cache is being used as a temporary supply of
3428 necessary storage before the SDRAM controller is setup. It's
3429 beyond the scope of this list to expain the details, but you
3430 can see how this works by studying the cache architecture and
3431 operation in the architecture and processor-specific manuals.
3433 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3434 is another option for the system designer to use as an
3435 initial stack/ram area prior to SDRAM being available. Either
3436 option should work for you. Using CS 4 should be fine if your
3437 board designers haven't used it for something that would
3438 cause you grief during the initial boot! It is frequently not
3441 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3442 with your processor/board/system design. The default value
3443 you will find in any recent u-boot distribution in
3444 walnut.h should work for you. I'd set it to a value larger
3445 than your SDRAM module. If you have a 64MB SDRAM module, set
3446 it above 400_0000. Just make sure your board has no resources
3447 that are supposed to respond to that address! That code in
3448 start.S has been around a while and should work as is when
3449 you get the config right.
3454 It is essential to remember this, since it has some impact on the C
3455 code for the initialization procedures:
3457 * Initialized global data (data segment) is read-only. Do not attempt
3460 * Do not use any unitialized global data (or implicitely initialized
3461 as zero data - BSS segment) at all - this is undefined, initiali-
3462 zation is performed later (when relocating to RAM).
3464 * Stack space is very limited. Avoid big data buffers or things like
3467 Having only the stack as writable memory limits means we cannot use
3468 normal global data to share information beween the code. But it
3469 turned out that the implementation of U-Boot can be greatly
3470 simplified by making a global data structure (gd_t) available to all
3471 functions. We could pass a pointer to this data as argument to _all_
3472 functions, but this would bloat the code. Instead we use a feature of
3473 the GCC compiler (Global Register Variables) to share the data: we
3474 place a pointer (gd) to the global data into a register which we
3475 reserve for this purpose.
3477 When choosing a register for such a purpose we are restricted by the
3478 relevant (E)ABI specifications for the current architecture, and by
3479 GCC's implementation.
3481 For PowerPC, the following registers have specific use:
3484 R3-R4: parameter passing and return values
3485 R5-R10: parameter passing
3486 R13: small data area pointer
3490 (U-Boot also uses R14 as internal GOT pointer.)
3492 ==> U-Boot will use R29 to hold a pointer to the global data
3494 Note: on PPC, we could use a static initializer (since the
3495 address of the global data structure is known at compile time),
3496 but it turned out that reserving a register results in somewhat
3497 smaller code - although the code savings are not that big (on
3498 average for all boards 752 bytes for the whole U-Boot image,
3499 624 text + 127 data).
3501 On ARM, the following registers are used:
3503 R0: function argument word/integer result
3504 R1-R3: function argument word
3506 R10: stack limit (used only if stack checking if enabled)
3507 R11: argument (frame) pointer
3508 R12: temporary workspace
3511 R15: program counter
3513 ==> U-Boot will use R8 to hold a pointer to the global data
3515 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3516 or current versions of GCC may "optimize" the code too much.
3521 U-Boot runs in system state and uses physical addresses, i.e. the
3522 MMU is not used either for address mapping nor for memory protection.
3524 The available memory is mapped to fixed addresses using the memory
3525 controller. In this process, a contiguous block is formed for each
3526 memory type (Flash, SDRAM, SRAM), even when it consists of several
3527 physical memory banks.
3529 U-Boot is installed in the first 128 kB of the first Flash bank (on
3530 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3531 booting and sizing and initializing DRAM, the code relocates itself
3532 to the upper end of DRAM. Immediately below the U-Boot code some
3533 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3534 configuration setting]. Below that, a structure with global Board
3535 Info data is placed, followed by the stack (growing downward).
3537 Additionally, some exception handler code is copied to the low 8 kB
3538 of DRAM (0x00000000 ... 0x00001FFF).
3540 So a typical memory configuration with 16 MB of DRAM could look like
3543 0x0000 0000 Exception Vector code
3546 0x0000 2000 Free for Application Use
3552 0x00FB FF20 Monitor Stack (Growing downward)
3553 0x00FB FFAC Board Info Data and permanent copy of global data
3554 0x00FC 0000 Malloc Arena
3557 0x00FE 0000 RAM Copy of Monitor Code
3558 ... eventually: LCD or video framebuffer
3559 ... eventually: pRAM (Protected RAM - unchanged by reset)
3560 0x00FF FFFF [End of RAM]
3563 System Initialization:
3564 ----------------------
3566 In the reset configuration, U-Boot starts at the reset entry point
3567 (on most PowerPC systens at address 0x00000100). Because of the reset
3568 configuration for CS0# this is a mirror of the onboard Flash memory.
3569 To be able to re-map memory U-Boot then jumps to its link address.
3570 To be able to implement the initialization code in C, a (small!)
3571 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3572 which provide such a feature like MPC8xx or MPC8260), or in a locked
3573 part of the data cache. After that, U-Boot initializes the CPU core,
3574 the caches and the SIU.
3576 Next, all (potentially) available memory banks are mapped using a
3577 preliminary mapping. For example, we put them on 512 MB boundaries
3578 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3579 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3580 programmed for SDRAM access. Using the temporary configuration, a
3581 simple memory test is run that determines the size of the SDRAM
3584 When there is more than one SDRAM bank, and the banks are of
3585 different size, the largest is mapped first. For equal size, the first
3586 bank (CS2#) is mapped first. The first mapping is always for address
3587 0x00000000, with any additional banks following immediately to create
3588 contiguous memory starting from 0.
3590 Then, the monitor installs itself at the upper end of the SDRAM area
3591 and allocates memory for use by malloc() and for the global Board
3592 Info data; also, the exception vector code is copied to the low RAM
3593 pages, and the final stack is set up.
3595 Only after this relocation will you have a "normal" C environment;
3596 until that you are restricted in several ways, mostly because you are
3597 running from ROM, and because the code will have to be relocated to a
3601 U-Boot Porting Guide:
3602 ----------------------
3604 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3608 int main (int argc, char *argv[])
3610 sighandler_t no_more_time;
3612 signal (SIGALRM, no_more_time);
3613 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3615 if (available_money > available_manpower) {
3616 pay consultant to port U-Boot;
3620 Download latest U-Boot source;
3622 Subscribe to u-boot-users mailing list;
3625 email ("Hi, I am new to U-Boot, how do I get started?");
3629 Read the README file in the top level directory;
3630 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3631 Read the source, Luke;
3634 if (available_money > toLocalCurrency ($2500)) {
3637 Add a lot of aggravation and time;
3640 Create your own board support subdirectory;
3642 Create your own board config file;
3646 Add / modify source code;
3650 email ("Hi, I am having problems...");
3652 Send patch file to Wolfgang;
3657 void no_more_time (int sig)
3666 All contributions to U-Boot should conform to the Linux kernel
3667 coding style; see the file "Documentation/CodingStyle" and the script
3668 "scripts/Lindent" in your Linux kernel source directory. In sources
3669 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3670 spaces before parameters to function calls) is actually used.
3672 Source files originating from a different project (for example the
3673 MTD subsystem) are generally exempt from these guidelines and are not
3674 reformated to ease subsequent migration to newer versions of those
3677 Please note that U-Boot is implemented in C (and to some small parts in
3678 Assembler); no C++ is used, so please do not use C++ style comments (//)
3681 Please also stick to the following formatting rules:
3682 - remove any trailing white space
3683 - use TAB characters for indentation, not spaces
3684 - make sure NOT to use DOS '\r\n' line feeds
3685 - do not add more than 2 empty lines to source files
3686 - do not add trailing empty lines to source files
3688 Submissions which do not conform to the standards may be returned
3689 with a request to reformat the changes.
3695 Since the number of patches for U-Boot is growing, we need to
3696 establish some rules. Submissions which do not conform to these rules
3697 may be rejected, even when they contain important and valuable stuff.
3699 Patches shall be sent to the u-boot-users mailing list.
3701 When you send a patch, please include the following information with
3704 * For bug fixes: a description of the bug and how your patch fixes
3705 this bug. Please try to include a way of demonstrating that the
3706 patch actually fixes something.
3708 * For new features: a description of the feature and your
3711 * A CHANGELOG entry as plaintext (separate from the patch)
3713 * For major contributions, your entry to the CREDITS file
3715 * When you add support for a new board, don't forget to add this
3716 board to the MAKEALL script, too.
3718 * If your patch adds new configuration options, don't forget to
3719 document these in the README file.
3721 * The patch itself. If you are accessing the CVS repository use "cvs
3722 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3723 version of diff does not support these options, then get the latest
3724 version of GNU diff.
3726 The current directory when running this command shall be the top
3727 level directory of the U-Boot source tree, or it's parent directory
3728 (i. e. please make sure that your patch includes sufficient
3729 directory information for the affected files).
3731 We accept patches as plain text, MIME attachments or as uuencoded
3734 * If one logical set of modifications affects or creates several
3735 files, all these changes shall be submitted in a SINGLE patch file.
3737 * Changesets that contain different, unrelated modifications shall be
3738 submitted as SEPARATE patches, one patch per changeset.
3743 * Before sending the patch, run the MAKEALL script on your patched
3744 source tree and make sure that no errors or warnings are reported
3745 for any of the boards.
3747 * Keep your modifications to the necessary minimum: A patch
3748 containing several unrelated changes or arbitrary reformats will be
3749 returned with a request to re-formatting / split it.
3751 * If you modify existing code, make sure that your new code does not
3752 add to the memory footprint of the code ;-) Small is beautiful!
3753 When adding new features, these should compile conditionally only
3754 (using #ifdef), and the resulting code with the new feature
3755 disabled must not need more memory than the old code without your
3758 * Remember that there is a size limit of 40 kB per message on the
3759 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob