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 -----------------------------------------------
724 CONFIG_CMD_DFL Default configuration; at the moment
725 this is includes all commands, except
726 the ones marked with "*" in the list
729 If you don't define CONFIG_COMMANDS it defaults to
730 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
731 override the default settings in the respective
734 EXAMPLE: If you want all functions except of network
735 support you can write:
737 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
740 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
742 Note: Don't enable the "icache" and "dcache" commands
743 (configuration option CFG_CMD_CACHE) unless you know
744 what you (and your U-Boot users) are doing. Data
745 cache cannot be enabled on systems like the 8xx or
746 8260 (where accesses to the IMMR region must be
747 uncached), and it cannot be disabled on all other
748 systems where we (mis-) use the data cache to hold an
749 initial stack and some data.
752 XXX - this list needs to get updated!
756 If this variable is defined, it enables watchdog
757 support. There must be support in the platform specific
758 code for a watchdog. For the 8xx and 8260 CPUs, the
759 SIU Watchdog feature is enabled in the SYPCR
763 CONFIG_VERSION_VARIABLE
764 If this variable is defined, an environment variable
765 named "ver" is created by U-Boot showing the U-Boot
766 version as printed by the "version" command.
767 This variable is readonly.
771 When CFG_CMD_DATE is selected, the type of the RTC
772 has to be selected, too. Define exactly one of the
775 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
776 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
777 CONFIG_RTC_MC146818 - use MC146818 RTC
778 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
779 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
780 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
781 CONFIG_RTC_DS164x - use Dallas DS164x RTC
782 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
784 Note that if the RTC uses I2C, then the I2C interface
785 must also be configured. See I2C Support, below.
789 When CONFIG_TIMESTAMP is selected, the timestamp
790 (date and time) of an image is printed by image
791 commands like bootm or iminfo. This option is
792 automatically enabled when you select CFG_CMD_DATE .
795 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
796 and/or CONFIG_ISO_PARTITION
798 If IDE or SCSI support is enabled (CFG_CMD_IDE or
799 CFG_CMD_SCSI) you must configure support for at least
800 one partition type as well.
803 CONFIG_IDE_RESET_ROUTINE - this is defined in several
804 board configurations files but used nowhere!
806 CONFIG_IDE_RESET - is this is defined, IDE Reset will
807 be performed by calling the function
808 ide_set_reset(int reset)
809 which has to be defined in a board specific file
814 Set this to enable ATAPI support.
819 Set this to enable support for disks larger than 137GB
820 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
821 Whithout these , LBA48 support uses 32bit variables and will 'only'
822 support disks up to 2.1TB.
825 When enabled, makes the IDE subsystem use 64bit sector addresses.
829 At the moment only there is only support for the
830 SYM53C8XX SCSI controller; define
831 CONFIG_SCSI_SYM53C8XX to enable it.
833 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
834 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
835 CFG_SCSI_MAX_LUN] can be adjusted to define the
836 maximum numbers of LUNs, SCSI ID's and target
838 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
840 - NETWORK Support (PCI):
842 Support for Intel 8254x gigabit chips.
845 Support for Intel 82557/82559/82559ER chips.
846 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
847 write routine for first time initialisation.
850 Support for Digital 2114x chips.
851 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
852 modem chip initialisation (KS8761/QS6611).
855 Support for National dp83815 chips.
858 Support for National dp8382[01] gigabit chips.
860 - NETWORK Support (other):
862 CONFIG_DRIVER_LAN91C96
863 Support for SMSC's LAN91C96 chips.
866 Define this to hold the physical address
867 of the LAN91C96's I/O space
869 CONFIG_LAN91C96_USE_32_BIT
870 Define this to enable 32 bit addressing
872 CONFIG_DRIVER_SMC91111
873 Support for SMSC's LAN91C111 chip
876 Define this to hold the physical address
877 of the device (I/O space)
879 CONFIG_SMC_USE_32_BIT
880 Define this if data bus is 32 bits
882 CONFIG_SMC_USE_IOFUNCS
883 Define this to use i/o functions instead of macros
884 (some hardware wont work with macros)
887 At the moment only the UHCI host controller is
888 supported (PIP405, MIP405, MPC5200); define
889 CONFIG_USB_UHCI to enable it.
890 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
891 and define CONFIG_USB_STORAGE to enable the USB
894 Supported are USB Keyboards and USB Floppy drives
896 MPC5200 USB requires additional defines:
898 for 528 MHz Clock: 0x0001bbbb
900 for differential drivers: 0x00001000
901 for single ended drivers: 0x00005000
905 The MMC controller on the Intel PXA is supported. To
906 enable this define CONFIG_MMC. The MMC can be
907 accessed from the boot prompt by mapping the device
908 to physical memory similar to flash. Command line is
909 enabled with CFG_CMD_MMC. The MMC driver also works with
910 the FAT fs. This is enabled with CFG_CMD_FAT.
912 - Journaling Flash filesystem support:
913 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
914 CONFIG_JFFS2_NAND_DEV
915 Define these for a default partition on a NAND device
917 CFG_JFFS2_FIRST_SECTOR,
918 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
919 Define these for a default partition on a NOR device
922 Define this to create an own partition. You have to provide a
923 function struct part_info* jffs2_part_info(int part_num)
925 If you define only one JFFS2 partition you may also want to
926 #define CFG_JFFS_SINGLE_PART 1
927 to disable the command chpart. This is the default when you
928 have not defined a custom partition
933 Define this to enable standard (PC-Style) keyboard
937 Standard PC keyboard driver with US (is default) and
938 GERMAN key layout (switch via environment 'keymap=de') support.
939 Export function i8042_kbd_init, i8042_tstc and i8042_getc
940 for cfb_console. Supports cursor blinking.
945 Define this to enable video support (for output to
950 Enable Chips & Technologies 69000 Video chip
952 CONFIG_VIDEO_SMI_LYNXEM
953 Enable Silicon Motion SMI 712/710/810 Video chip. The
954 video output is selected via environment 'videoout'
955 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
958 For the CT69000 and SMI_LYNXEM drivers, videomode is
959 selected via environment 'videomode'. Two diferent ways
961 - "videomode=num" 'num' is a standard LiLo mode numbers.
962 Following standard modes are supported (* is default):
964 Colors 640x480 800x600 1024x768 1152x864 1280x1024
965 -------------+---------------------------------------------
966 8 bits | 0x301* 0x303 0x305 0x161 0x307
967 15 bits | 0x310 0x313 0x316 0x162 0x319
968 16 bits | 0x311 0x314 0x317 0x163 0x31A
969 24 bits | 0x312 0x315 0x318 ? 0x31B
970 -------------+---------------------------------------------
971 (i.e. setenv videomode 317; saveenv; reset;)
973 - "videomode=bootargs" all the video parameters are parsed
974 from the bootargs. (See drivers/videomodes.c)
977 CONFIG_VIDEO_SED13806
978 Enable Epson SED13806 driver. This driver supports 8bpp
979 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
980 or CONFIG_VIDEO_SED13806_16BPP
985 Define this to enable a custom keyboard support.
986 This simply calls drv_keyboard_init() which must be
987 defined in your board-specific files.
988 The only board using this so far is RBC823.
990 - LCD Support: CONFIG_LCD
992 Define this to enable LCD support (for output to LCD
993 display); also select one of the supported displays
994 by defining one of these:
996 CONFIG_NEC_NL6448AC33:
998 NEC NL6448AC33-18. Active, color, single scan.
1000 CONFIG_NEC_NL6448BC20
1002 NEC NL6448BC20-08. 6.5", 640x480.
1003 Active, color, single scan.
1005 CONFIG_NEC_NL6448BC33_54
1007 NEC NL6448BC33-54. 10.4", 640x480.
1008 Active, color, single scan.
1012 Sharp 320x240. Active, color, single scan.
1013 It isn't 16x9, and I am not sure what it is.
1015 CONFIG_SHARP_LQ64D341
1017 Sharp LQ64D341 display, 640x480.
1018 Active, color, single scan.
1022 HLD1045 display, 640x480.
1023 Active, color, single scan.
1027 Optrex CBL50840-2 NF-FW 99 22 M5
1029 Hitachi LMG6912RPFC-00T
1033 320x240. Black & white.
1035 Normally display is black on white background; define
1036 CFG_WHITE_ON_BLACK to get it inverted.
1038 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1040 If this option is set, the environment is checked for
1041 a variable "splashimage". If found, the usual display
1042 of logo, copyright and system information on the LCD
1043 is suppressed and the BMP image at the address
1044 specified in "splashimage" is loaded instead. The
1045 console is redirected to the "nulldev", too. This
1046 allows for a "silent" boot where a splash screen is
1047 loaded very quickly after power-on.
1049 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1051 If this option is set, additionally to standard BMP
1052 images, gzipped BMP images can be displayed via the
1053 splashscreen support or the bmp command.
1055 - Compression support:
1058 If this option is set, support for bzip2 compressed
1059 images is included. If not, only uncompressed and gzip
1060 compressed images are supported.
1062 NOTE: the bzip2 algorithm requires a lot of RAM, so
1063 the malloc area (as defined by CFG_MALLOC_LEN) should
1069 The address of PHY on MII bus.
1071 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1073 The clock frequency of the MII bus
1077 If this option is set, support for speed/duplex
1078 detection of Gigabit PHY is included.
1080 CONFIG_PHY_RESET_DELAY
1082 Some PHY like Intel LXT971A need extra delay after
1083 reset before any MII register access is possible.
1084 For such PHY, set this option to the usec delay
1085 required. (minimum 300usec for LXT971A)
1087 CONFIG_PHY_CMD_DELAY (ppc4xx)
1089 Some PHY like Intel LXT971A need extra delay after
1090 command issued before MII status register can be read
1097 Define a default value for ethernet address to use
1098 for the respective ethernet interface, in case this
1099 is not determined automatically.
1104 Define a default value for the IP address to use for
1105 the default ethernet interface, in case this is not
1106 determined through e.g. bootp.
1108 - Server IP address:
1111 Defines a default value for theIP address of a TFTP
1112 server to contact when using the "tftboot" command.
1114 - BOOTP Recovery Mode:
1115 CONFIG_BOOTP_RANDOM_DELAY
1117 If you have many targets in a network that try to
1118 boot using BOOTP, you may want to avoid that all
1119 systems send out BOOTP requests at precisely the same
1120 moment (which would happen for instance at recovery
1121 from a power failure, when all systems will try to
1122 boot, thus flooding the BOOTP server. Defining
1123 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1124 inserted before sending out BOOTP requests. The
1125 following delays are insterted then:
1127 1st BOOTP request: delay 0 ... 1 sec
1128 2nd BOOTP request: delay 0 ... 2 sec
1129 3rd BOOTP request: delay 0 ... 4 sec
1131 BOOTP requests: delay 0 ... 8 sec
1133 - DHCP Advanced Options:
1136 You can fine tune the DHCP functionality by adding
1137 these flags to the CONFIG_BOOTP_MASK define:
1139 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1140 serverip from a DHCP server, it is possible that more
1141 than one DNS serverip is offered to the client.
1142 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1143 serverip will be stored in the additional environment
1144 variable "dnsip2". The first DNS serverip is always
1145 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1146 is added to the CONFIG_BOOTP_MASK.
1148 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1149 to do a dynamic update of a DNS server. To do this, they
1150 need the hostname of the DHCP requester.
1151 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1152 CONFIG_BOOTP_MASK, the content of the "hostname"
1153 environment variable is passed as option 12 to
1157 CONFIG_CDP_DEVICE_ID
1159 The device id used in CDP trigger frames.
1161 CONFIG_CDP_DEVICE_ID_PREFIX
1163 A two character string which is prefixed to the MAC address
1168 A printf format string which contains the ascii name of
1169 the port. Normally is set to "eth%d" which sets
1170 eth0 for the first ethernet, eth1 for the second etc.
1172 CONFIG_CDP_CAPABILITIES
1174 A 32bit integer which indicates the device capabilities;
1175 0x00000010 for a normal host which does not forwards.
1179 An ascii string containing the version of the software.
1183 An ascii string containing the name of the platform.
1187 A 32bit integer sent on the trigger.
1189 CONFIG_CDP_POWER_CONSUMPTION
1191 A 16bit integer containing the power consumption of the
1192 device in .1 of milliwatts.
1194 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1196 A byte containing the id of the VLAN.
1198 - Status LED: CONFIG_STATUS_LED
1200 Several configurations allow to display the current
1201 status using a LED. For instance, the LED will blink
1202 fast while running U-Boot code, stop blinking as
1203 soon as a reply to a BOOTP request was received, and
1204 start blinking slow once the Linux kernel is running
1205 (supported by a status LED driver in the Linux
1206 kernel). Defining CONFIG_STATUS_LED enables this
1209 - CAN Support: CONFIG_CAN_DRIVER
1211 Defining CONFIG_CAN_DRIVER enables CAN driver support
1212 on those systems that support this (optional)
1213 feature, like the TQM8xxL modules.
1215 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1217 These enable I2C serial bus commands. Defining either of
1218 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1219 include the appropriate I2C driver for the selected cpu.
1221 This will allow you to use i2c commands at the u-boot
1222 command line (as long as you set CFG_CMD_I2C in
1223 CONFIG_COMMANDS) and communicate with i2c based realtime
1224 clock chips. See common/cmd_i2c.c for a description of the
1225 command line interface.
1227 CONFIG_I2C_CMD_TREE is a recommended option that places
1228 all I2C commands under a single 'i2c' root command. The
1229 older 'imm', 'imd', 'iprobe' etc. commands are considered
1230 deprecated and may disappear in the future.
1232 CONFIG_HARD_I2C selects a hardware I2C controller.
1234 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1235 bit-banging) driver instead of CPM or similar hardware
1238 There are several other quantities that must also be
1239 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1241 In both cases you will need to define CFG_I2C_SPEED
1242 to be the frequency (in Hz) at which you wish your i2c bus
1243 to run and CFG_I2C_SLAVE to be the address of this node (ie
1244 the cpu's i2c node address).
1246 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1247 sets the cpu up as a master node and so its address should
1248 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1249 p.16-473). So, set CFG_I2C_SLAVE to 0.
1251 That's all that's required for CONFIG_HARD_I2C.
1253 If you use the software i2c interface (CONFIG_SOFT_I2C)
1254 then the following macros need to be defined (examples are
1255 from include/configs/lwmon.h):
1259 (Optional). Any commands necessary to enable the I2C
1260 controller or configure ports.
1262 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1266 (Only for MPC8260 CPU). The I/O port to use (the code
1267 assumes both bits are on the same port). Valid values
1268 are 0..3 for ports A..D.
1272 The code necessary to make the I2C data line active
1273 (driven). If the data line is open collector, this
1276 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1280 The code necessary to make the I2C data line tri-stated
1281 (inactive). If the data line is open collector, this
1284 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1288 Code that returns TRUE if the I2C data line is high,
1291 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1295 If <bit> is TRUE, sets the I2C data line high. If it
1296 is FALSE, it clears it (low).
1298 eg: #define I2C_SDA(bit) \
1299 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1300 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1304 If <bit> is TRUE, sets the I2C clock line high. If it
1305 is FALSE, it clears it (low).
1307 eg: #define I2C_SCL(bit) \
1308 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1309 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1313 This delay is invoked four times per clock cycle so this
1314 controls the rate of data transfer. The data rate thus
1315 is 1 / (I2C_DELAY * 4). Often defined to be something
1318 #define I2C_DELAY udelay(2)
1322 When a board is reset during an i2c bus transfer
1323 chips might think that the current transfer is still
1324 in progress. On some boards it is possible to access
1325 the i2c SCLK line directly, either by using the
1326 processor pin as a GPIO or by having a second pin
1327 connected to the bus. If this option is defined a
1328 custom i2c_init_board() routine in boards/xxx/board.c
1329 is run early in the boot sequence.
1331 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1333 This option enables configuration of bi_iic_fast[] flags
1334 in u-boot bd_info structure based on u-boot environment
1335 variable "i2cfast". (see also i2cfast)
1337 CONFIG_I2C_MULTI_BUS
1339 This option allows the use of multiple I2C buses, each of which
1340 must have a controller. At any point in time, only one bus is
1341 active. To switch to a different bus, use the 'i2c dev' command.
1342 Note that bus numbering is zero-based.
1346 This option specifies a list of I2C devices that will be skipped
1347 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1348 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1349 pairs. Otherwise, specify a 1D array of device addresses
1352 #undef CONFIG_I2C_MULTI_BUS
1353 #define CFG_I2C_NOPROBES {0x50,0x68}
1355 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1357 #define CONFIG_I2C_MULTI_BUS
1358 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1360 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1364 If defined, then this indicates the I2C bus number for DDR SPD.
1365 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1369 If defined, then this indicates the I2C bus number for the RTC.
1370 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1374 If defined, then this indicates the I2C bus number for the DTT.
1375 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1379 Define this option if you want to use Freescale's I2C driver in
1383 - SPI Support: CONFIG_SPI
1385 Enables SPI driver (so far only tested with
1386 SPI EEPROM, also an instance works with Crystal A/D and
1387 D/As on the SACSng board)
1391 Enables extended (16-bit) SPI EEPROM addressing.
1392 (symmetrical to CONFIG_I2C_X)
1396 Enables a software (bit-bang) SPI driver rather than
1397 using hardware support. This is a general purpose
1398 driver that only requires three general I/O port pins
1399 (two outputs, one input) to function. If this is
1400 defined, the board configuration must define several
1401 SPI configuration items (port pins to use, etc). For
1402 an example, see include/configs/sacsng.h.
1404 - FPGA Support: CONFIG_FPGA_COUNT
1406 Specify the number of FPGA devices to support.
1410 Used to specify the types of FPGA devices. For example,
1411 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1413 CFG_FPGA_PROG_FEEDBACK
1415 Enable printing of hash marks during FPGA configuration.
1419 Enable checks on FPGA configuration interface busy
1420 status by the configuration function. This option
1421 will require a board or device specific function to
1426 If defined, a function that provides delays in the FPGA
1427 configuration driver.
1429 CFG_FPGA_CHECK_CTRLC
1430 Allow Control-C to interrupt FPGA configuration
1432 CFG_FPGA_CHECK_ERROR
1434 Check for configuration errors during FPGA bitfile
1435 loading. For example, abort during Virtex II
1436 configuration if the INIT_B line goes low (which
1437 indicated a CRC error).
1441 Maximum time to wait for the INIT_B line to deassert
1442 after PROB_B has been deasserted during a Virtex II
1443 FPGA configuration sequence. The default time is 500
1448 Maximum time to wait for BUSY to deassert during
1449 Virtex II FPGA configuration. The default is 5 mS.
1451 CFG_FPGA_WAIT_CONFIG
1453 Time to wait after FPGA configuration. The default is
1456 - Configuration Management:
1459 If defined, this string will be added to the U-Boot
1460 version information (U_BOOT_VERSION)
1462 - Vendor Parameter Protection:
1464 U-Boot considers the values of the environment
1465 variables "serial#" (Board Serial Number) and
1466 "ethaddr" (Ethernet Address) to be parameters that
1467 are set once by the board vendor / manufacturer, and
1468 protects these variables from casual modification by
1469 the user. Once set, these variables are read-only,
1470 and write or delete attempts are rejected. You can
1471 change this behviour:
1473 If CONFIG_ENV_OVERWRITE is #defined in your config
1474 file, the write protection for vendor parameters is
1475 completely disabled. Anybody can change or delete
1478 Alternatively, if you #define _both_ CONFIG_ETHADDR
1479 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1480 ethernet address is installed in the environment,
1481 which can be changed exactly ONCE by the user. [The
1482 serial# is unaffected by this, i. e. it remains
1488 Define this variable to enable the reservation of
1489 "protected RAM", i. e. RAM which is not overwritten
1490 by U-Boot. Define CONFIG_PRAM to hold the number of
1491 kB you want to reserve for pRAM. You can overwrite
1492 this default value by defining an environment
1493 variable "pram" to the number of kB you want to
1494 reserve. Note that the board info structure will
1495 still show the full amount of RAM. If pRAM is
1496 reserved, a new environment variable "mem" will
1497 automatically be defined to hold the amount of
1498 remaining RAM in a form that can be passed as boot
1499 argument to Linux, for instance like that:
1501 setenv bootargs ... mem=\${mem}
1504 This way you can tell Linux not to use this memory,
1505 either, which results in a memory region that will
1506 not be affected by reboots.
1508 *WARNING* If your board configuration uses automatic
1509 detection of the RAM size, you must make sure that
1510 this memory test is non-destructive. So far, the
1511 following board configurations are known to be
1514 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1515 HERMES, IP860, RPXlite, LWMON, LANTEC,
1516 PCU_E, FLAGADM, TQM8260
1521 Define this variable to stop the system in case of a
1522 fatal error, so that you have to reset it manually.
1523 This is probably NOT a good idea for an embedded
1524 system where you want to system to reboot
1525 automatically as fast as possible, but it may be
1526 useful during development since you can try to debug
1527 the conditions that lead to the situation.
1529 CONFIG_NET_RETRY_COUNT
1531 This variable defines the number of retries for
1532 network operations like ARP, RARP, TFTP, or BOOTP
1533 before giving up the operation. If not defined, a
1534 default value of 5 is used.
1536 - Command Interpreter:
1537 CONFIG_AUTO_COMPLETE
1539 Enable auto completion of commands using TAB.
1541 Note that this feature has NOT been implemented yet
1542 for the "hush" shell.
1547 Define this variable to enable the "hush" shell (from
1548 Busybox) as command line interpreter, thus enabling
1549 powerful command line syntax like
1550 if...then...else...fi conditionals or `&&' and '||'
1551 constructs ("shell scripts").
1553 If undefined, you get the old, much simpler behaviour
1554 with a somewhat smaller memory footprint.
1559 This defines the secondary prompt string, which is
1560 printed when the command interpreter needs more input
1561 to complete a command. Usually "> ".
1565 In the current implementation, the local variables
1566 space and global environment variables space are
1567 separated. Local variables are those you define by
1568 simply typing `name=value'. To access a local
1569 variable later on, you have write `$name' or
1570 `${name}'; to execute the contents of a variable
1571 directly type `$name' at the command prompt.
1573 Global environment variables are those you use
1574 setenv/printenv to work with. To run a command stored
1575 in such a variable, you need to use the run command,
1576 and you must not use the '$' sign to access them.
1578 To store commands and special characters in a
1579 variable, please use double quotation marks
1580 surrounding the whole text of the variable, instead
1581 of the backslashes before semicolons and special
1584 - Commandline Editing and History:
1585 CONFIG_CMDLINE_EDITING
1587 Enable editiong and History functions for interactive
1588 commandline input operations
1590 - Default Environment:
1591 CONFIG_EXTRA_ENV_SETTINGS
1593 Define this to contain any number of null terminated
1594 strings (variable = value pairs) that will be part of
1595 the default environment compiled into the boot image.
1597 For example, place something like this in your
1598 board's config file:
1600 #define CONFIG_EXTRA_ENV_SETTINGS \
1604 Warning: This method is based on knowledge about the
1605 internal format how the environment is stored by the
1606 U-Boot code. This is NOT an official, exported
1607 interface! Although it is unlikely that this format
1608 will change soon, there is no guarantee either.
1609 You better know what you are doing here.
1611 Note: overly (ab)use of the default environment is
1612 discouraged. Make sure to check other ways to preset
1613 the environment like the autoscript function or the
1616 - DataFlash Support:
1617 CONFIG_HAS_DATAFLASH
1619 Defining this option enables DataFlash features and
1620 allows to read/write in Dataflash via the standard
1623 - SystemACE Support:
1626 Adding this option adds support for Xilinx SystemACE
1627 chips attached via some sort of local bus. The address
1628 of the chip must alsh be defined in the
1629 CFG_SYSTEMACE_BASE macro. For example:
1631 #define CONFIG_SYSTEMACE
1632 #define CFG_SYSTEMACE_BASE 0xf0000000
1634 When SystemACE support is added, the "ace" device type
1635 becomes available to the fat commands, i.e. fatls.
1637 - TFTP Fixed UDP Port:
1640 If this is defined, the environment variable tftpsrcp
1641 is used to supply the TFTP UDP source port value.
1642 If tftpsrcp isn't defined, the normal pseudo-random port
1643 number generator is used.
1645 Also, the environment variable tftpdstp is used to supply
1646 the TFTP UDP destination port value. If tftpdstp isn't
1647 defined, the normal port 69 is used.
1649 The purpose for tftpsrcp is to allow a TFTP server to
1650 blindly start the TFTP transfer using the pre-configured
1651 target IP address and UDP port. This has the effect of
1652 "punching through" the (Windows XP) firewall, allowing
1653 the remainder of the TFTP transfer to proceed normally.
1654 A better solution is to properly configure the firewall,
1655 but sometimes that is not allowed.
1657 - Show boot progress:
1658 CONFIG_SHOW_BOOT_PROGRESS
1660 Defining this option allows to add some board-
1661 specific code (calling a user-provided function
1662 "show_boot_progress(int)") that enables you to show
1663 the system's boot progress on some display (for
1664 example, some LED's) on your board. At the moment,
1665 the following checkpoints are implemented:
1668 1 common/cmd_bootm.c before attempting to boot an image
1669 -1 common/cmd_bootm.c Image header has bad magic number
1670 2 common/cmd_bootm.c Image header has correct magic number
1671 -2 common/cmd_bootm.c Image header has bad checksum
1672 3 common/cmd_bootm.c Image header has correct checksum
1673 -3 common/cmd_bootm.c Image data has bad checksum
1674 4 common/cmd_bootm.c Image data has correct checksum
1675 -4 common/cmd_bootm.c Image is for unsupported architecture
1676 5 common/cmd_bootm.c Architecture check OK
1677 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1678 6 common/cmd_bootm.c Image Type check OK
1679 -6 common/cmd_bootm.c gunzip uncompression error
1680 -7 common/cmd_bootm.c Unimplemented compression type
1681 7 common/cmd_bootm.c Uncompression OK
1682 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1683 8 common/cmd_bootm.c Image Type check OK
1684 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1685 9 common/cmd_bootm.c Start initial ramdisk verification
1686 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1687 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1688 10 common/cmd_bootm.c Ramdisk header is OK
1689 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1690 11 common/cmd_bootm.c Ramdisk data has correct checksum
1691 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1692 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1693 13 common/cmd_bootm.c Start multifile image verification
1694 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1695 15 common/cmd_bootm.c All preparation done, transferring control to OS
1697 -30 lib_ppc/board.c Fatal error, hang the system
1698 -31 post/post.c POST test failed, detected by post_output_backlog()
1699 -32 post/post.c POST test failed, detected by post_run_single()
1701 -1 common/cmd_doc.c Bad usage of "doc" command
1702 -1 common/cmd_doc.c No boot device
1703 -1 common/cmd_doc.c Unknown Chip ID on boot device
1704 -1 common/cmd_doc.c Read Error on boot device
1705 -1 common/cmd_doc.c Image header has bad magic number
1707 -1 common/cmd_ide.c Bad usage of "ide" command
1708 -1 common/cmd_ide.c No boot device
1709 -1 common/cmd_ide.c Unknown boot device
1710 -1 common/cmd_ide.c Unknown partition table
1711 -1 common/cmd_ide.c Invalid partition type
1712 -1 common/cmd_ide.c Read Error on boot device
1713 -1 common/cmd_ide.c Image header has bad magic number
1715 -1 common/cmd_nand.c Bad usage of "nand" command
1716 -1 common/cmd_nand.c No boot device
1717 -1 common/cmd_nand.c Unknown Chip ID on boot device
1718 -1 common/cmd_nand.c Read Error on boot device
1719 -1 common/cmd_nand.c Image header has bad magic number
1721 -1 common/env_common.c Environment has a bad CRC, using default
1727 [so far only for SMDK2400 and TRAB boards]
1729 - Modem support endable:
1730 CONFIG_MODEM_SUPPORT
1732 - RTS/CTS Flow control enable:
1735 - Modem debug support:
1736 CONFIG_MODEM_SUPPORT_DEBUG
1738 Enables debugging stuff (char screen[1024], dbg())
1739 for modem support. Useful only with BDI2000.
1741 - Interrupt support (PPC):
1743 There are common interrupt_init() and timer_interrupt()
1744 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1745 for cpu specific initialization. interrupt_init_cpu()
1746 should set decrementer_count to appropriate value. If
1747 cpu resets decrementer automatically after interrupt
1748 (ppc4xx) it should set decrementer_count to zero.
1749 timer_interrupt() calls timer_interrupt_cpu() for cpu
1750 specific handling. If board has watchdog / status_led
1751 / other_activity_monitor it works automatically from
1752 general timer_interrupt().
1756 In the target system modem support is enabled when a
1757 specific key (key combination) is pressed during
1758 power-on. Otherwise U-Boot will boot normally
1759 (autoboot). The key_pressed() fuction is called from
1760 board_init(). Currently key_pressed() is a dummy
1761 function, returning 1 and thus enabling modem
1764 If there are no modem init strings in the
1765 environment, U-Boot proceed to autoboot; the
1766 previous output (banner, info printfs) will be
1769 See also: doc/README.Modem
1772 Configuration Settings:
1773 -----------------------
1775 - CFG_LONGHELP: Defined when you want long help messages included;
1776 undefine this when you're short of memory.
1778 - CFG_PROMPT: This is what U-Boot prints on the console to
1779 prompt for user input.
1781 - CFG_CBSIZE: Buffer size for input from the Console
1783 - CFG_PBSIZE: Buffer size for Console output
1785 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1787 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1788 the application (usually a Linux kernel) when it is
1791 - CFG_BAUDRATE_TABLE:
1792 List of legal baudrate settings for this board.
1794 - CFG_CONSOLE_INFO_QUIET
1795 Suppress display of console information at boot.
1797 - CFG_CONSOLE_IS_IN_ENV
1798 If the board specific function
1799 extern int overwrite_console (void);
1800 returns 1, the stdin, stderr and stdout are switched to the
1801 serial port, else the settings in the environment are used.
1803 - CFG_CONSOLE_OVERWRITE_ROUTINE
1804 Enable the call to overwrite_console().
1806 - CFG_CONSOLE_ENV_OVERWRITE
1807 Enable overwrite of previous console environment settings.
1809 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1810 Begin and End addresses of the area used by the
1814 Enable an alternate, more extensive memory test.
1816 - CFG_MEMTEST_SCRATCH:
1817 Scratch address used by the alternate memory test
1818 You only need to set this if address zero isn't writeable
1820 - CFG_TFTP_LOADADDR:
1821 Default load address for network file downloads
1823 - CFG_LOADS_BAUD_CHANGE:
1824 Enable temporary baudrate change while serial download
1827 Physical start address of SDRAM. _Must_ be 0 here.
1830 Physical start address of Motherboard I/O (if using a
1834 Physical start address of Flash memory.
1837 Physical start address of boot monitor code (set by
1838 make config files to be same as the text base address
1839 (TEXT_BASE) used when linking) - same as
1840 CFG_FLASH_BASE when booting from flash.
1843 Size of memory reserved for monitor code, used to
1844 determine _at_compile_time_ (!) if the environment is
1845 embedded within the U-Boot image, or in a separate
1849 Size of DRAM reserved for malloc() use.
1852 Normally compressed uImages are limited to an
1853 uncompressed size of 8 MBytes. If this is not enough,
1854 you can define CFG_BOOTM_LEN in your board config file
1855 to adjust this setting to your needs.
1858 Maximum size of memory mapped by the startup code of
1859 the Linux kernel; all data that must be processed by
1860 the Linux kernel (bd_info, boot arguments, eventually
1861 initrd image) must be put below this limit.
1863 - CFG_MAX_FLASH_BANKS:
1864 Max number of Flash memory banks
1866 - CFG_MAX_FLASH_SECT:
1867 Max number of sectors on a Flash chip
1869 - CFG_FLASH_ERASE_TOUT:
1870 Timeout for Flash erase operations (in ms)
1872 - CFG_FLASH_WRITE_TOUT:
1873 Timeout for Flash write operations (in ms)
1875 - CFG_FLASH_LOCK_TOUT
1876 Timeout for Flash set sector lock bit operation (in ms)
1878 - CFG_FLASH_UNLOCK_TOUT
1879 Timeout for Flash clear lock bits operation (in ms)
1881 - CFG_FLASH_PROTECTION
1882 If defined, hardware flash sectors protection is used
1883 instead of U-Boot software protection.
1885 - CFG_DIRECT_FLASH_TFTP:
1887 Enable TFTP transfers directly to flash memory;
1888 without this option such a download has to be
1889 performed in two steps: (1) download to RAM, and (2)
1890 copy from RAM to flash.
1892 The two-step approach is usually more reliable, since
1893 you can check if the download worked before you erase
1894 the flash, but in some situations (when sytem RAM is
1895 too limited to allow for a tempory copy of the
1896 downloaded image) this option may be very useful.
1899 Define if the flash driver uses extra elements in the
1900 common flash structure for storing flash geometry.
1902 - CFG_FLASH_CFI_DRIVER
1903 This option also enables the building of the cfi_flash driver
1904 in the drivers directory
1906 - CFG_FLASH_QUIET_TEST
1907 If this option is defined, the common CFI flash doesn't
1908 print it's warning upon not recognized FLASH banks. This
1909 is useful, if some of the configured banks are only
1910 optionally available.
1912 - CFG_RX_ETH_BUFFER:
1913 Defines the number of ethernet receive buffers. On some
1914 ethernet controllers it is recommended to set this value
1915 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1916 buffers can be full shortly after enabling the interface
1917 on high ethernet traffic.
1918 Defaults to 4 if not defined.
1920 The following definitions that deal with the placement and management
1921 of environment data (variable area); in general, we support the
1922 following configurations:
1924 - CFG_ENV_IS_IN_FLASH:
1926 Define this if the environment is in flash memory.
1928 a) The environment occupies one whole flash sector, which is
1929 "embedded" in the text segment with the U-Boot code. This
1930 happens usually with "bottom boot sector" or "top boot
1931 sector" type flash chips, which have several smaller
1932 sectors at the start or the end. For instance, such a
1933 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1934 such a case you would place the environment in one of the
1935 4 kB sectors - with U-Boot code before and after it. With
1936 "top boot sector" type flash chips, you would put the
1937 environment in one of the last sectors, leaving a gap
1938 between U-Boot and the environment.
1942 Offset of environment data (variable area) to the
1943 beginning of flash memory; for instance, with bottom boot
1944 type flash chips the second sector can be used: the offset
1945 for this sector is given here.
1947 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1951 This is just another way to specify the start address of
1952 the flash sector containing the environment (instead of
1955 - CFG_ENV_SECT_SIZE:
1957 Size of the sector containing the environment.
1960 b) Sometimes flash chips have few, equal sized, BIG sectors.
1961 In such a case you don't want to spend a whole sector for
1966 If you use this in combination with CFG_ENV_IS_IN_FLASH
1967 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1968 of this flash sector for the environment. This saves
1969 memory for the RAM copy of the environment.
1971 It may also save flash memory if you decide to use this
1972 when your environment is "embedded" within U-Boot code,
1973 since then the remainder of the flash sector could be used
1974 for U-Boot code. It should be pointed out that this is
1975 STRONGLY DISCOURAGED from a robustness point of view:
1976 updating the environment in flash makes it always
1977 necessary to erase the WHOLE sector. If something goes
1978 wrong before the contents has been restored from a copy in
1979 RAM, your target system will be dead.
1981 - CFG_ENV_ADDR_REDUND
1984 These settings describe a second storage area used to hold
1985 a redundand copy of the environment data, so that there is
1986 a valid backup copy in case there is a power failure during
1987 a "saveenv" operation.
1989 BE CAREFUL! Any changes to the flash layout, and some changes to the
1990 source code will make it necessary to adapt <board>/u-boot.lds*
1994 - CFG_ENV_IS_IN_NVRAM:
1996 Define this if you have some non-volatile memory device
1997 (NVRAM, battery buffered SRAM) which you want to use for the
2003 These two #defines are used to determin the memory area you
2004 want to use for environment. It is assumed that this memory
2005 can just be read and written to, without any special
2008 BE CAREFUL! The first access to the environment happens quite early
2009 in U-Boot initalization (when we try to get the setting of for the
2010 console baudrate). You *MUST* have mappend your NVRAM area then, or
2013 Please note that even with NVRAM we still use a copy of the
2014 environment in RAM: we could work on NVRAM directly, but we want to
2015 keep settings there always unmodified except somebody uses "saveenv"
2016 to save the current settings.
2019 - CFG_ENV_IS_IN_EEPROM:
2021 Use this if you have an EEPROM or similar serial access
2022 device and a driver for it.
2027 These two #defines specify the offset and size of the
2028 environment area within the total memory of your EEPROM.
2030 - CFG_I2C_EEPROM_ADDR:
2031 If defined, specified the chip address of the EEPROM device.
2032 The default address is zero.
2034 - CFG_EEPROM_PAGE_WRITE_BITS:
2035 If defined, the number of bits used to address bytes in a
2036 single page in the EEPROM device. A 64 byte page, for example
2037 would require six bits.
2039 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2040 If defined, the number of milliseconds to delay between
2041 page writes. The default is zero milliseconds.
2043 - CFG_I2C_EEPROM_ADDR_LEN:
2044 The length in bytes of the EEPROM memory array address. Note
2045 that this is NOT the chip address length!
2047 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2048 EEPROM chips that implement "address overflow" are ones
2049 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2050 address and the extra bits end up in the "chip address" bit
2051 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2054 Note that we consider the length of the address field to
2055 still be one byte because the extra address bits are hidden
2056 in the chip address.
2059 The size in bytes of the EEPROM device.
2062 - CFG_ENV_IS_IN_DATAFLASH:
2064 Define this if you have a DataFlash memory device which you
2065 want to use for the environment.
2071 These three #defines specify the offset and size of the
2072 environment area within the total memory of your DataFlash placed
2073 at the specified address.
2075 - CFG_ENV_IS_IN_NAND:
2077 Define this if you have a NAND device which you want to use
2078 for the environment.
2083 These two #defines specify the offset and size of the environment
2084 area within the first NAND device.
2086 - CFG_ENV_OFFSET_REDUND
2088 This setting describes a second storage area of CFG_ENV_SIZE
2089 size used to hold a redundant copy of the environment data,
2090 so that there is a valid backup copy in case there is a
2091 power failure during a "saveenv" operation.
2093 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2094 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2095 the NAND devices block size.
2097 - CFG_SPI_INIT_OFFSET
2099 Defines offset to the initial SPI buffer area in DPRAM. The
2100 area is used at an early stage (ROM part) if the environment
2101 is configured to reside in the SPI EEPROM: We need a 520 byte
2102 scratch DPRAM area. It is used between the two initialization
2103 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2104 to be a good choice since it makes it far enough from the
2105 start of the data area as well as from the stack pointer.
2107 Please note that the environment is read-only as long as the monitor
2108 has been relocated to RAM and a RAM copy of the environment has been
2109 created; also, when using EEPROM you will have to use getenv_r()
2110 until then to read environment variables.
2112 The environment is protected by a CRC32 checksum. Before the monitor
2113 is relocated into RAM, as a result of a bad CRC you will be working
2114 with the compiled-in default environment - *silently*!!! [This is
2115 necessary, because the first environment variable we need is the
2116 "baudrate" setting for the console - if we have a bad CRC, we don't
2117 have any device yet where we could complain.]
2119 Note: once the monitor has been relocated, then it will complain if
2120 the default environment is used; a new CRC is computed as soon as you
2121 use the "saveenv" command to store a valid environment.
2123 - CFG_FAULT_ECHO_LINK_DOWN:
2124 Echo the inverted Ethernet link state to the fault LED.
2126 Note: If this option is active, then CFG_FAULT_MII_ADDR
2127 also needs to be defined.
2129 - CFG_FAULT_MII_ADDR:
2130 MII address of the PHY to check for the Ethernet link state.
2132 - CFG_64BIT_VSPRINTF:
2133 Makes vsprintf (and all *printf functions) support printing
2134 of 64bit values by using the L quantifier
2136 - CFG_64BIT_STRTOUL:
2137 Adds simple_strtoull that returns a 64bit value
2139 Low Level (hardware related) configuration options:
2140 ---------------------------------------------------
2142 - CFG_CACHELINE_SIZE:
2143 Cache Line Size of the CPU.
2146 Default address of the IMMR after system reset.
2148 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2149 and RPXsuper) to be able to adjust the position of
2150 the IMMR register after a reset.
2152 - Floppy Disk Support:
2153 CFG_FDC_DRIVE_NUMBER
2155 the default drive number (default value 0)
2159 defines the spacing between fdc chipset registers
2164 defines the offset of register from address. It
2165 depends on which part of the data bus is connected to
2166 the fdc chipset. (default value 0)
2168 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2169 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2172 if CFG_FDC_HW_INIT is defined, then the function
2173 fdc_hw_init() is called at the beginning of the FDC
2174 setup. fdc_hw_init() must be provided by the board
2175 source code. It is used to make hardware dependant
2178 - CFG_IMMR: Physical address of the Internal Memory.
2179 DO NOT CHANGE unless you know exactly what you're
2180 doing! (11-4) [MPC8xx/82xx systems only]
2182 - CFG_INIT_RAM_ADDR:
2184 Start address of memory area that can be used for
2185 initial data and stack; please note that this must be
2186 writable memory that is working WITHOUT special
2187 initialization, i. e. you CANNOT use normal RAM which
2188 will become available only after programming the
2189 memory controller and running certain initialization
2192 U-Boot uses the following memory types:
2193 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2194 - MPC824X: data cache
2195 - PPC4xx: data cache
2197 - CFG_GBL_DATA_OFFSET:
2199 Offset of the initial data structure in the memory
2200 area defined by CFG_INIT_RAM_ADDR. Usually
2201 CFG_GBL_DATA_OFFSET is chosen such that the initial
2202 data is located at the end of the available space
2203 (sometimes written as (CFG_INIT_RAM_END -
2204 CFG_INIT_DATA_SIZE), and the initial stack is just
2205 below that area (growing from (CFG_INIT_RAM_ADDR +
2206 CFG_GBL_DATA_OFFSET) downward.
2209 On the MPC824X (or other systems that use the data
2210 cache for initial memory) the address chosen for
2211 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2212 point to an otherwise UNUSED address space between
2213 the top of RAM and the start of the PCI space.
2215 - CFG_SIUMCR: SIU Module Configuration (11-6)
2217 - CFG_SYPCR: System Protection Control (11-9)
2219 - CFG_TBSCR: Time Base Status and Control (11-26)
2221 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2223 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2225 - CFG_SCCR: System Clock and reset Control Register (15-27)
2227 - CFG_OR_TIMING_SDRAM:
2231 periodic timer for refresh
2233 - CFG_DER: Debug Event Register (37-47)
2235 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2236 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2237 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2239 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2241 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2242 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2243 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2244 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2246 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2247 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2248 Machine Mode Register and Memory Periodic Timer
2249 Prescaler definitions (SDRAM timing)
2251 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2252 enable I2C microcode relocation patch (MPC8xx);
2253 define relocation offset in DPRAM [DSP2]
2255 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2256 enable SPI microcode relocation patch (MPC8xx);
2257 define relocation offset in DPRAM [SCC4]
2260 Use OSCM clock mode on MBX8xx board. Be careful,
2261 wrong setting might damage your board. Read
2262 doc/README.MBX before setting this variable!
2264 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2265 Offset of the bootmode word in DPRAM used by post
2266 (Power On Self Tests). This definition overrides
2267 #define'd default value in commproc.h resp.
2270 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2271 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2272 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2273 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2274 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2275 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2276 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2277 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2278 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2281 Get DDR timing information from an I2C EEPROM. Common with pluggable
2282 memory modules such as SODIMMs
2284 I2C address of the SPD EEPROM
2287 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2288 Note that the value must resolve to something your driver can deal with.
2290 - CFG_83XX_DDR_USES_CS0
2291 Only for 83xx systems. If specified, then DDR should be configured
2292 using CS0 and CS1 instead of CS2 and CS3.
2294 - CFG_83XX_DDR_USES_CS0
2295 Only for 83xx systems. If specified, then DDR should be configured
2296 using CS0 and CS1 instead of CS2 and CS3.
2298 - CONFIG_ETHER_ON_FEC[12]
2299 Define to enable FEC[12] on a 8xx series processor.
2301 - CONFIG_FEC[12]_PHY
2302 Define to the hardcoded PHY address which corresponds
2303 to the given FEC; i. e.
2304 #define CONFIG_FEC1_PHY 4
2305 means that the PHY with address 4 is connected to FEC1
2307 When set to -1, means to probe for first available.
2309 - CONFIG_FEC[12]_PHY_NORXERR
2310 The PHY does not have a RXERR line (RMII only).
2311 (so program the FEC to ignore it).
2314 Enable RMII mode for all FECs.
2315 Note that this is a global option, we can't
2316 have one FEC in standard MII mode and another in RMII mode.
2318 - CONFIG_CRC32_VERIFY
2319 Add a verify option to the crc32 command.
2322 => crc32 -v <address> <count> <crc32>
2324 Where address/count indicate a memory area
2325 and crc32 is the correct crc32 which the
2329 Add the "loopw" memory command. This only takes effect if
2330 the memory commands are activated globally (CFG_CMD_MEM).
2333 Add the "mdc" and "mwc" memory commands. These are cyclic
2338 This command will print 4 bytes (10,11,12,13) each 500 ms.
2340 => mwc.l 100 12345678 10
2341 This command will write 12345678 to address 100 all 10 ms.
2343 This only takes effect if the memory commands are activated
2344 globally (CFG_CMD_MEM).
2346 - CONFIG_SKIP_LOWLEVEL_INIT
2347 - CONFIG_SKIP_RELOCATE_UBOOT
2349 [ARM only] If these variables are defined, then
2350 certain low level initializations (like setting up
2351 the memory controller) are omitted and/or U-Boot does
2352 not relocate itself into RAM.
2353 Normally these variables MUST NOT be defined. The
2354 only exception is when U-Boot is loaded (to RAM) by
2355 some other boot loader or by a debugger which
2356 performs these intializations itself.
2359 Building the Software:
2360 ======================
2362 Building U-Boot has been tested in native PPC environments (on a
2363 PowerBook G3 running LinuxPPC 2000) and in cross environments
2364 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2367 If you are not using a native PPC environment, it is assumed that you
2368 have the GNU cross compiling tools available in your path and named
2369 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2370 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2371 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2374 CROSS_COMPILE = ppc_4xx-
2377 U-Boot is intended to be simple to build. After installing the
2378 sources you must configure U-Boot for one specific board type. This
2383 where "NAME_config" is the name of one of the existing
2384 configurations; the following names are supported:
2386 ADCIOP_config FPS860L_config omap730p2_config
2387 ADS860_config GEN860T_config pcu_e_config
2389 AR405_config GENIETV_config PIP405_config
2390 at91rm9200dk_config GTH_config QS823_config
2391 CANBT_config hermes_config QS850_config
2392 cmi_mpc5xx_config hymod_config QS860T_config
2393 cogent_common_config IP860_config RPXlite_config
2394 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2395 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2396 CPCI405_config JSE_config rsdproto_config
2397 CPCIISER4_config LANTEC_config Sandpoint8240_config
2398 csb272_config lwmon_config sbc8260_config
2399 CU824_config MBX860T_config sbc8560_33_config
2400 DUET_ADS_config MBX_config sbc8560_66_config
2401 EBONY_config mpc7448hpc2_config SM850_config
2402 ELPT860_config MPC8260ADS_config SPD823TS_config
2403 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2404 ETX094_config MPC8540EVAL_config SXNI855T_config
2405 FADS823_config NMPC8560ADS_config TQM823L_config
2406 FADS850SAR_config NETVIA_config TQM850L_config
2407 FADS860T_config omap1510inn_config TQM855L_config
2408 FPS850L_config omap1610h2_config TQM860L_config
2409 omap1610inn_config walnut_config
2410 omap5912osk_config Yukon8220_config
2411 omap2420h4_config ZPC1900_config
2413 Note: for some board special configuration names may exist; check if
2414 additional information is available from the board vendor; for
2415 instance, the TQM823L systems are available without (standard)
2416 or with LCD support. You can select such additional "features"
2417 when chosing the configuration, i. e.
2420 - will configure for a plain TQM823L, i. e. no LCD support
2422 make TQM823L_LCD_config
2423 - will configure for a TQM823L with U-Boot console on LCD
2428 Finally, type "make all", and you should get some working U-Boot
2429 images ready for download to / installation on your system:
2431 - "u-boot.bin" is a raw binary image
2432 - "u-boot" is an image in ELF binary format
2433 - "u-boot.srec" is in Motorola S-Record format
2435 By default the build is performed locally and the objects are saved
2436 in the source directory. One of the two methods can be used to change
2437 this behavior and build U-Boot to some external directory:
2439 1. Add O= to the make command line invocations:
2441 make O=/tmp/build distclean
2442 make O=/tmp/build NAME_config
2443 make O=/tmp/build all
2445 2. Set environment variable BUILD_DIR to point to the desired location:
2447 export BUILD_DIR=/tmp/build
2452 Note that the command line "O=" setting overrides the BUILD_DIR environment
2456 Please be aware that the Makefiles assume you are using GNU make, so
2457 for instance on NetBSD you might need to use "gmake" instead of
2461 If the system board that you have is not listed, then you will need
2462 to port U-Boot to your hardware platform. To do this, follow these
2465 1. Add a new configuration option for your board to the toplevel
2466 "Makefile" and to the "MAKEALL" script, using the existing
2467 entries as examples. Note that here and at many other places
2468 boards and other names are listed in alphabetical sort order. Please
2470 2. Create a new directory to hold your board specific code. Add any
2471 files you need. In your board directory, you will need at least
2472 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2473 3. Create a new configuration file "include/configs/<board>.h" for
2475 3. If you're porting U-Boot to a new CPU, then also create a new
2476 directory to hold your CPU specific code. Add any files you need.
2477 4. Run "make <board>_config" with your new name.
2478 5. Type "make", and you should get a working "u-boot.srec" file
2479 to be installed on your target system.
2480 6. Debug and solve any problems that might arise.
2481 [Of course, this last step is much harder than it sounds.]
2484 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2485 ==============================================================
2487 If you have modified U-Boot sources (for instance added a new board
2488 or support for new devices, a new CPU, etc.) you are expected to
2489 provide feedback to the other developers. The feedback normally takes
2490 the form of a "patch", i. e. a context diff against a certain (latest
2491 official or latest in CVS) version of U-Boot sources.
2493 But before you submit such a patch, please verify that your modifi-
2494 cation did not break existing code. At least make sure that *ALL* of
2495 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2496 just run the "MAKEALL" script, which will configure and build U-Boot
2497 for ALL supported system. Be warned, this will take a while. You can
2498 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2499 environment variable to the script, i. e. to use the cross tools from
2500 MontaVista's Hard Hat Linux you can type
2502 CROSS_COMPILE=ppc_8xx- MAKEALL
2504 or to build on a native PowerPC system you can type
2506 CROSS_COMPILE=' ' MAKEALL
2508 When using the MAKEALL script, the default behaviour is to build U-Boot
2509 in the source directory. This location can be changed by setting the
2510 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2511 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2512 <source dir>/LOG directory. This default location can be changed by
2513 setting the MAKEALL_LOGDIR environment variable. For example:
2515 export BUILD_DIR=/tmp/build
2516 export MAKEALL_LOGDIR=/tmp/log
2517 CROSS_COMPILE=ppc_8xx- MAKEALL
2519 With the above settings build objects are saved in the /tmp/build, log
2520 files are saved in the /tmp/log and the source tree remains clean during
2521 the whole build process.
2524 See also "U-Boot Porting Guide" below.
2527 Monitor Commands - Overview:
2528 ============================
2530 go - start application at address 'addr'
2531 run - run commands in an environment variable
2532 bootm - boot application image from memory
2533 bootp - boot image via network using BootP/TFTP protocol
2534 tftpboot- boot image via network using TFTP protocol
2535 and env variables "ipaddr" and "serverip"
2536 (and eventually "gatewayip")
2537 rarpboot- boot image via network using RARP/TFTP protocol
2538 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2539 loads - load S-Record file over serial line
2540 loadb - load binary file over serial line (kermit mode)
2542 mm - memory modify (auto-incrementing)
2543 nm - memory modify (constant address)
2544 mw - memory write (fill)
2546 cmp - memory compare
2547 crc32 - checksum calculation
2548 imd - i2c memory display
2549 imm - i2c memory modify (auto-incrementing)
2550 inm - i2c memory modify (constant address)
2551 imw - i2c memory write (fill)
2552 icrc32 - i2c checksum calculation
2553 iprobe - probe to discover valid I2C chip addresses
2554 iloop - infinite loop on address range
2555 isdram - print SDRAM configuration information
2556 sspi - SPI utility commands
2557 base - print or set address offset
2558 printenv- print environment variables
2559 setenv - set environment variables
2560 saveenv - save environment variables to persistent storage
2561 protect - enable or disable FLASH write protection
2562 erase - erase FLASH memory
2563 flinfo - print FLASH memory information
2564 bdinfo - print Board Info structure
2565 iminfo - print header information for application image
2566 coninfo - print console devices and informations
2567 ide - IDE sub-system
2568 loop - infinite loop on address range
2569 loopw - infinite write loop on address range
2570 mtest - simple RAM test
2571 icache - enable or disable instruction cache
2572 dcache - enable or disable data cache
2573 reset - Perform RESET of the CPU
2574 echo - echo args to console
2575 version - print monitor version
2576 help - print online help
2577 ? - alias for 'help'
2580 Monitor Commands - Detailed Description:
2581 ========================================
2585 For now: just type "help <command>".
2588 Environment Variables:
2589 ======================
2591 U-Boot supports user configuration using Environment Variables which
2592 can be made persistent by saving to Flash memory.
2594 Environment Variables are set using "setenv", printed using
2595 "printenv", and saved to Flash using "saveenv". Using "setenv"
2596 without a value can be used to delete a variable from the
2597 environment. As long as you don't save the environment you are
2598 working with an in-memory copy. In case the Flash area containing the
2599 environment is erased by accident, a default environment is provided.
2601 Some configuration options can be set using Environment Variables:
2603 baudrate - see CONFIG_BAUDRATE
2605 bootdelay - see CONFIG_BOOTDELAY
2607 bootcmd - see CONFIG_BOOTCOMMAND
2609 bootargs - Boot arguments when booting an RTOS image
2611 bootfile - Name of the image to load with TFTP
2613 autoload - if set to "no" (any string beginning with 'n'),
2614 "bootp" will just load perform a lookup of the
2615 configuration from the BOOTP server, but not try to
2616 load any image using TFTP
2618 autostart - if set to "yes", an image loaded using the "bootp",
2619 "rarpboot", "tftpboot" or "diskboot" commands will
2620 be automatically started (by internally calling
2623 If set to "no", a standalone image passed to the
2624 "bootm" command will be copied to the load address
2625 (and eventually uncompressed), but NOT be started.
2626 This can be used to load and uncompress arbitrary
2629 i2cfast - (PPC405GP|PPC405EP only)
2630 if set to 'y' configures Linux I2C driver for fast
2631 mode (400kHZ). This environment variable is used in
2632 initialization code. So, for changes to be effective
2633 it must be saved and board must be reset.
2635 initrd_high - restrict positioning of initrd images:
2636 If this variable is not set, initrd images will be
2637 copied to the highest possible address in RAM; this
2638 is usually what you want since it allows for
2639 maximum initrd size. If for some reason you want to
2640 make sure that the initrd image is loaded below the
2641 CFG_BOOTMAPSZ limit, you can set this environment
2642 variable to a value of "no" or "off" or "0".
2643 Alternatively, you can set it to a maximum upper
2644 address to use (U-Boot will still check that it
2645 does not overwrite the U-Boot stack and data).
2647 For instance, when you have a system with 16 MB
2648 RAM, and want to reserve 4 MB from use by Linux,
2649 you can do this by adding "mem=12M" to the value of
2650 the "bootargs" variable. However, now you must make
2651 sure that the initrd image is placed in the first
2652 12 MB as well - this can be done with
2654 setenv initrd_high 00c00000
2656 If you set initrd_high to 0xFFFFFFFF, this is an
2657 indication to U-Boot that all addresses are legal
2658 for the Linux kernel, including addresses in flash
2659 memory. In this case U-Boot will NOT COPY the
2660 ramdisk at all. This may be useful to reduce the
2661 boot time on your system, but requires that this
2662 feature is supported by your Linux kernel.
2664 ipaddr - IP address; needed for tftpboot command
2666 loadaddr - Default load address for commands like "bootp",
2667 "rarpboot", "tftpboot", "loadb" or "diskboot"
2669 loads_echo - see CONFIG_LOADS_ECHO
2671 serverip - TFTP server IP address; needed for tftpboot command
2673 bootretry - see CONFIG_BOOT_RETRY_TIME
2675 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2677 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2679 ethprime - When CONFIG_NET_MULTI is enabled controls which
2680 interface is used first.
2682 ethact - When CONFIG_NET_MULTI is enabled controls which
2683 interface is currently active. For example you
2684 can do the following
2686 => setenv ethact FEC ETHERNET
2687 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2688 => setenv ethact SCC ETHERNET
2689 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2691 netretry - When set to "no" each network operation will
2692 either succeed or fail without retrying.
2693 When set to "once" the network operation will
2694 fail when all the available network interfaces
2695 are tried once without success.
2696 Useful on scripts which control the retry operation
2699 tftpsrcport - If this is set, the value is used for TFTP's
2702 tftpdstport - If this is set, the value is used for TFTP's UDP
2703 destination port instead of the Well Know Port 69.
2705 vlan - When set to a value < 4095 the traffic over
2706 ethernet is encapsulated/received over 802.1q
2709 The following environment variables may be used and automatically
2710 updated by the network boot commands ("bootp" and "rarpboot"),
2711 depending the information provided by your boot server:
2713 bootfile - see above
2714 dnsip - IP address of your Domain Name Server
2715 dnsip2 - IP address of your secondary Domain Name Server
2716 gatewayip - IP address of the Gateway (Router) to use
2717 hostname - Target hostname
2719 netmask - Subnet Mask
2720 rootpath - Pathname of the root filesystem on the NFS server
2721 serverip - see above
2724 There are two special Environment Variables:
2726 serial# - contains hardware identification information such
2727 as type string and/or serial number
2728 ethaddr - Ethernet address
2730 These variables can be set only once (usually during manufacturing of
2731 the board). U-Boot refuses to delete or overwrite these variables
2732 once they have been set once.
2735 Further special Environment Variables:
2737 ver - Contains the U-Boot version string as printed
2738 with the "version" command. This variable is
2739 readonly (see CONFIG_VERSION_VARIABLE).
2742 Please note that changes to some configuration parameters may take
2743 only effect after the next boot (yes, that's just like Windoze :-).
2746 Command Line Parsing:
2747 =====================
2749 There are two different command line parsers available with U-Boot:
2750 the old "simple" one, and the much more powerful "hush" shell:
2752 Old, simple command line parser:
2753 --------------------------------
2755 - supports environment variables (through setenv / saveenv commands)
2756 - several commands on one line, separated by ';'
2757 - variable substitution using "... ${name} ..." syntax
2758 - special characters ('$', ';') can be escaped by prefixing with '\',
2760 setenv bootcmd bootm \${address}
2761 - You can also escape text by enclosing in single apostrophes, for example:
2762 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2767 - similar to Bourne shell, with control structures like
2768 if...then...else...fi, for...do...done; while...do...done,
2769 until...do...done, ...
2770 - supports environment ("global") variables (through setenv / saveenv
2771 commands) and local shell variables (through standard shell syntax
2772 "name=value"); only environment variables can be used with "run"
2778 (1) If a command line (or an environment variable executed by a "run"
2779 command) contains several commands separated by semicolon, and
2780 one of these commands fails, then the remaining commands will be
2783 (2) If you execute several variables with one call to run (i. e.
2784 calling run with a list af variables as arguments), any failing
2785 command will cause "run" to terminate, i. e. the remaining
2786 variables are not executed.
2788 Note for Redundant Ethernet Interfaces:
2789 =======================================
2791 Some boards come with redundant ethernet interfaces; U-Boot supports
2792 such configurations and is capable of automatic selection of a
2793 "working" interface when needed. MAC assignment works as follows:
2795 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2796 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2797 "eth1addr" (=>eth1), "eth2addr", ...
2799 If the network interface stores some valid MAC address (for instance
2800 in SROM), this is used as default address if there is NO correspon-
2801 ding setting in the environment; if the corresponding environment
2802 variable is set, this overrides the settings in the card; that means:
2804 o If the SROM has a valid MAC address, and there is no address in the
2805 environment, the SROM's address is used.
2807 o If there is no valid address in the SROM, and a definition in the
2808 environment exists, then the value from the environment variable is
2811 o If both the SROM and the environment contain a MAC address, and
2812 both addresses are the same, this MAC address is used.
2814 o If both the SROM and the environment contain a MAC address, and the
2815 addresses differ, the value from the environment is used and a
2818 o If neither SROM nor the environment contain a MAC address, an error
2825 The "boot" commands of this monitor operate on "image" files which
2826 can be basicly anything, preceeded by a special header; see the
2827 definitions in include/image.h for details; basicly, the header
2828 defines the following image properties:
2830 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2831 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2832 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2833 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2834 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2835 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2836 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2837 * Compression Type (uncompressed, gzip, bzip2)
2843 The header is marked by a special Magic Number, and both the header
2844 and the data portions of the image are secured against corruption by
2851 Although U-Boot should support any OS or standalone application
2852 easily, the main focus has always been on Linux during the design of
2855 U-Boot includes many features that so far have been part of some
2856 special "boot loader" code within the Linux kernel. Also, any
2857 "initrd" images to be used are no longer part of one big Linux image;
2858 instead, kernel and "initrd" are separate images. This implementation
2859 serves several purposes:
2861 - the same features can be used for other OS or standalone
2862 applications (for instance: using compressed images to reduce the
2863 Flash memory footprint)
2865 - it becomes much easier to port new Linux kernel versions because
2866 lots of low-level, hardware dependent stuff are done by U-Boot
2868 - the same Linux kernel image can now be used with different "initrd"
2869 images; of course this also means that different kernel images can
2870 be run with the same "initrd". This makes testing easier (you don't
2871 have to build a new "zImage.initrd" Linux image when you just
2872 change a file in your "initrd"). Also, a field-upgrade of the
2873 software is easier now.
2879 Porting Linux to U-Boot based systems:
2880 ---------------------------------------
2882 U-Boot cannot save you from doing all the necessary modifications to
2883 configure the Linux device drivers for use with your target hardware
2884 (no, we don't intend to provide a full virtual machine interface to
2887 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2889 Just make sure your machine specific header file (for instance
2890 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2891 Information structure as we define in include/u-boot.h, and make
2892 sure that your definition of IMAP_ADDR uses the same value as your
2893 U-Boot configuration in CFG_IMMR.
2896 Configuring the Linux kernel:
2897 -----------------------------
2899 No specific requirements for U-Boot. Make sure you have some root
2900 device (initial ramdisk, NFS) for your target system.
2903 Building a Linux Image:
2904 -----------------------
2906 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2907 not used. If you use recent kernel source, a new build target
2908 "uImage" will exist which automatically builds an image usable by
2909 U-Boot. Most older kernels also have support for a "pImage" target,
2910 which was introduced for our predecessor project PPCBoot and uses a
2911 100% compatible format.
2920 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2921 encapsulate a compressed Linux kernel image with header information,
2922 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2924 * build a standard "vmlinux" kernel image (in ELF binary format):
2926 * convert the kernel into a raw binary image:
2928 ${CROSS_COMPILE}-objcopy -O binary \
2929 -R .note -R .comment \
2930 -S vmlinux linux.bin
2932 * compress the binary image:
2936 * package compressed binary image for U-Boot:
2938 mkimage -A ppc -O linux -T kernel -C gzip \
2939 -a 0 -e 0 -n "Linux Kernel Image" \
2940 -d linux.bin.gz uImage
2943 The "mkimage" tool can also be used to create ramdisk images for use
2944 with U-Boot, either separated from the Linux kernel image, or
2945 combined into one file. "mkimage" encapsulates the images with a 64
2946 byte header containing information about target architecture,
2947 operating system, image type, compression method, entry points, time
2948 stamp, CRC32 checksums, etc.
2950 "mkimage" can be called in two ways: to verify existing images and
2951 print the header information, or to build new images.
2953 In the first form (with "-l" option) mkimage lists the information
2954 contained in the header of an existing U-Boot image; this includes
2955 checksum verification:
2957 tools/mkimage -l image
2958 -l ==> list image header information
2960 The second form (with "-d" option) is used to build a U-Boot image
2961 from a "data file" which is used as image payload:
2963 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2964 -n name -d data_file image
2965 -A ==> set architecture to 'arch'
2966 -O ==> set operating system to 'os'
2967 -T ==> set image type to 'type'
2968 -C ==> set compression type 'comp'
2969 -a ==> set load address to 'addr' (hex)
2970 -e ==> set entry point to 'ep' (hex)
2971 -n ==> set image name to 'name'
2972 -d ==> use image data from 'datafile'
2974 Right now, all Linux kernels for PowerPC systems use the same load
2975 address (0x00000000), but the entry point address depends on the
2978 - 2.2.x kernels have the entry point at 0x0000000C,
2979 - 2.3.x and later kernels have the entry point at 0x00000000.
2981 So a typical call to build a U-Boot image would read:
2983 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2984 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2985 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2986 > examples/uImage.TQM850L
2987 Image Name: 2.4.4 kernel for TQM850L
2988 Created: Wed Jul 19 02:34:59 2000
2989 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2990 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2991 Load Address: 0x00000000
2992 Entry Point: 0x00000000
2994 To verify the contents of the image (or check for corruption):
2996 -> tools/mkimage -l examples/uImage.TQM850L
2997 Image Name: 2.4.4 kernel for TQM850L
2998 Created: Wed Jul 19 02:34:59 2000
2999 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3000 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3001 Load Address: 0x00000000
3002 Entry Point: 0x00000000
3004 NOTE: for embedded systems where boot time is critical you can trade
3005 speed for memory and install an UNCOMPRESSED image instead: this
3006 needs more space in Flash, but boots much faster since it does not
3007 need to be uncompressed:
3009 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3010 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3011 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3012 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3013 > examples/uImage.TQM850L-uncompressed
3014 Image Name: 2.4.4 kernel for TQM850L
3015 Created: Wed Jul 19 02:34:59 2000
3016 Image Type: PowerPC Linux Kernel Image (uncompressed)
3017 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3018 Load Address: 0x00000000
3019 Entry Point: 0x00000000
3022 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3023 when your kernel is intended to use an initial ramdisk:
3025 -> tools/mkimage -n 'Simple Ramdisk Image' \
3026 > -A ppc -O linux -T ramdisk -C gzip \
3027 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3028 Image Name: Simple Ramdisk Image
3029 Created: Wed Jan 12 14:01:50 2000
3030 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3031 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3032 Load Address: 0x00000000
3033 Entry Point: 0x00000000
3036 Installing a Linux Image:
3037 -------------------------
3039 To downloading a U-Boot image over the serial (console) interface,
3040 you must convert the image to S-Record format:
3042 objcopy -I binary -O srec examples/image examples/image.srec
3044 The 'objcopy' does not understand the information in the U-Boot
3045 image header, so the resulting S-Record file will be relative to
3046 address 0x00000000. To load it to a given address, you need to
3047 specify the target address as 'offset' parameter with the 'loads'
3050 Example: install the image to address 0x40100000 (which on the
3051 TQM8xxL is in the first Flash bank):
3053 => erase 40100000 401FFFFF
3059 ## Ready for S-Record download ...
3060 ~>examples/image.srec
3061 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3063 15989 15990 15991 15992
3064 [file transfer complete]
3066 ## Start Addr = 0x00000000
3069 You can check the success of the download using the 'iminfo' command;
3070 this includes a checksum verification so you can be sure no data
3071 corruption happened:
3075 ## Checking Image at 40100000 ...
3076 Image Name: 2.2.13 for initrd on TQM850L
3077 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3078 Data Size: 335725 Bytes = 327 kB = 0 MB
3079 Load Address: 00000000
3080 Entry Point: 0000000c
3081 Verifying Checksum ... OK
3087 The "bootm" command is used to boot an application that is stored in
3088 memory (RAM or Flash). In case of a Linux kernel image, the contents
3089 of the "bootargs" environment variable is passed to the kernel as
3090 parameters. You can check and modify this variable using the
3091 "printenv" and "setenv" commands:
3094 => printenv bootargs
3095 bootargs=root=/dev/ram
3097 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3099 => printenv bootargs
3100 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3103 ## Booting Linux kernel at 40020000 ...
3104 Image Name: 2.2.13 for NFS on TQM850L
3105 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3106 Data Size: 381681 Bytes = 372 kB = 0 MB
3107 Load Address: 00000000
3108 Entry Point: 0000000c
3109 Verifying Checksum ... OK
3110 Uncompressing Kernel Image ... OK
3111 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
3112 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3113 time_init: decrementer frequency = 187500000/60
3114 Calibrating delay loop... 49.77 BogoMIPS
3115 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3118 If you want to boot a Linux kernel with initial ram disk, you pass
3119 the memory addresses of both the kernel and the initrd image (PPBCOOT
3120 format!) to the "bootm" command:
3122 => imi 40100000 40200000
3124 ## Checking Image at 40100000 ...
3125 Image Name: 2.2.13 for initrd on TQM850L
3126 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3127 Data Size: 335725 Bytes = 327 kB = 0 MB
3128 Load Address: 00000000
3129 Entry Point: 0000000c
3130 Verifying Checksum ... OK
3132 ## Checking Image at 40200000 ...
3133 Image Name: Simple Ramdisk Image
3134 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3135 Data Size: 566530 Bytes = 553 kB = 0 MB
3136 Load Address: 00000000
3137 Entry Point: 00000000
3138 Verifying Checksum ... OK
3140 => bootm 40100000 40200000
3141 ## Booting Linux kernel at 40100000 ...
3142 Image Name: 2.2.13 for initrd on TQM850L
3143 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3144 Data Size: 335725 Bytes = 327 kB = 0 MB
3145 Load Address: 00000000
3146 Entry Point: 0000000c
3147 Verifying Checksum ... OK
3148 Uncompressing Kernel Image ... OK
3149 ## Loading RAMDisk Image at 40200000 ...
3150 Image Name: Simple Ramdisk Image
3151 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3152 Data Size: 566530 Bytes = 553 kB = 0 MB
3153 Load Address: 00000000
3154 Entry Point: 00000000
3155 Verifying Checksum ... OK
3156 Loading Ramdisk ... OK
3157 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
3158 Boot arguments: root=/dev/ram
3159 time_init: decrementer frequency = 187500000/60
3160 Calibrating delay loop... 49.77 BogoMIPS
3162 RAMDISK: Compressed image found at block 0
3163 VFS: Mounted root (ext2 filesystem).
3167 Boot Linux and pass a flat device tree:
3170 First, U-Boot must be compiled with the appropriate defines. See the section
3171 titled "Linux Kernel Interface" above for a more in depth explanation. The
3172 following is an example of how to start a kernel and pass an updated
3178 oft=oftrees/mpc8540ads.dtb
3179 => tftp $oftaddr $oft
3180 Speed: 1000, full duplex
3182 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3183 Filename 'oftrees/mpc8540ads.dtb'.
3184 Load address: 0x300000
3187 Bytes transferred = 4106 (100a hex)
3188 => tftp $loadaddr $bootfile
3189 Speed: 1000, full duplex
3191 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3193 Load address: 0x200000
3194 Loading:############
3196 Bytes transferred = 1029407 (fb51f hex)
3201 => bootm $loadaddr - $oftaddr
3202 ## Booting image at 00200000 ...
3203 Image Name: Linux-2.6.17-dirty
3204 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3205 Data Size: 1029343 Bytes = 1005.2 kB
3206 Load Address: 00000000
3207 Entry Point: 00000000
3208 Verifying Checksum ... OK
3209 Uncompressing Kernel Image ... OK
3210 Booting using flat device tree at 0x300000
3211 Using MPC85xx ADS machine description
3212 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3216 More About U-Boot Image Types:
3217 ------------------------------
3219 U-Boot supports the following image types:
3221 "Standalone Programs" are directly runnable in the environment
3222 provided by U-Boot; it is expected that (if they behave
3223 well) you can continue to work in U-Boot after return from
3224 the Standalone Program.
3225 "OS Kernel Images" are usually images of some Embedded OS which
3226 will take over control completely. Usually these programs
3227 will install their own set of exception handlers, device
3228 drivers, set up the MMU, etc. - this means, that you cannot
3229 expect to re-enter U-Boot except by resetting the CPU.
3230 "RAMDisk Images" are more or less just data blocks, and their
3231 parameters (address, size) are passed to an OS kernel that is
3233 "Multi-File Images" contain several images, typically an OS
3234 (Linux) kernel image and one or more data images like
3235 RAMDisks. This construct is useful for instance when you want
3236 to boot over the network using BOOTP etc., where the boot
3237 server provides just a single image file, but you want to get
3238 for instance an OS kernel and a RAMDisk image.
3240 "Multi-File Images" start with a list of image sizes, each
3241 image size (in bytes) specified by an "uint32_t" in network
3242 byte order. This list is terminated by an "(uint32_t)0".
3243 Immediately after the terminating 0 follow the images, one by
3244 one, all aligned on "uint32_t" boundaries (size rounded up to
3245 a multiple of 4 bytes).
3247 "Firmware Images" are binary images containing firmware (like
3248 U-Boot or FPGA images) which usually will be programmed to
3251 "Script files" are command sequences that will be executed by
3252 U-Boot's command interpreter; this feature is especially
3253 useful when you configure U-Boot to use a real shell (hush)
3254 as command interpreter.
3260 One of the features of U-Boot is that you can dynamically load and
3261 run "standalone" applications, which can use some resources of
3262 U-Boot like console I/O functions or interrupt services.
3264 Two simple examples are included with the sources:
3269 'examples/hello_world.c' contains a small "Hello World" Demo
3270 application; it is automatically compiled when you build U-Boot.
3271 It's configured to run at address 0x00040004, so you can play with it
3275 ## Ready for S-Record download ...
3276 ~>examples/hello_world.srec
3277 1 2 3 4 5 6 7 8 9 10 11 ...
3278 [file transfer complete]
3280 ## Start Addr = 0x00040004
3282 => go 40004 Hello World! This is a test.
3283 ## Starting application at 0x00040004 ...
3294 Hit any key to exit ...
3296 ## Application terminated, rc = 0x0
3298 Another example, which demonstrates how to register a CPM interrupt
3299 handler with the U-Boot code, can be found in 'examples/timer.c'.
3300 Here, a CPM timer is set up to generate an interrupt every second.
3301 The interrupt service routine is trivial, just printing a '.'
3302 character, but this is just a demo program. The application can be
3303 controlled by the following keys:
3305 ? - print current values og the CPM Timer registers
3306 b - enable interrupts and start timer
3307 e - stop timer and disable interrupts
3308 q - quit application
3311 ## Ready for S-Record download ...
3312 ~>examples/timer.srec
3313 1 2 3 4 5 6 7 8 9 10 11 ...
3314 [file transfer complete]
3316 ## Start Addr = 0x00040004
3319 ## Starting application at 0x00040004 ...
3322 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3325 [q, b, e, ?] Set interval 1000000 us
3328 [q, b, e, ?] ........
3329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3335 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3338 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3340 [q, b, e, ?] ...Stopping timer
3342 [q, b, e, ?] ## Application terminated, rc = 0x0
3348 Over time, many people have reported problems when trying to use the
3349 "minicom" terminal emulation program for serial download. I (wd)
3350 consider minicom to be broken, and recommend not to use it. Under
3351 Unix, I recommend to use C-Kermit for general purpose use (and
3352 especially for kermit binary protocol download ("loadb" command), and
3353 use "cu" for S-Record download ("loads" command).
3355 Nevertheless, if you absolutely want to use it try adding this
3356 configuration to your "File transfer protocols" section:
3358 Name Program Name U/D FullScr IO-Red. Multi
3359 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3360 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3366 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3367 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3369 Building requires a cross environment; it is known to work on
3370 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3371 need gmake since the Makefiles are not compatible with BSD make).
3372 Note that the cross-powerpc package does not install include files;
3373 attempting to build U-Boot will fail because <machine/ansi.h> is
3374 missing. This file has to be installed and patched manually:
3376 # cd /usr/pkg/cross/powerpc-netbsd/include
3378 # ln -s powerpc machine
3379 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3380 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3382 Native builds *don't* work due to incompatibilities between native
3383 and U-Boot include files.
3385 Booting assumes that (the first part of) the image booted is a
3386 stage-2 loader which in turn loads and then invokes the kernel
3387 proper. Loader sources will eventually appear in the NetBSD source
3388 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3389 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3392 Implementation Internals:
3393 =========================
3395 The following is not intended to be a complete description of every
3396 implementation detail. However, it should help to understand the
3397 inner workings of U-Boot and make it easier to port it to custom
3401 Initial Stack, Global Data:
3402 ---------------------------
3404 The implementation of U-Boot is complicated by the fact that U-Boot
3405 starts running out of ROM (flash memory), usually without access to
3406 system RAM (because the memory controller is not initialized yet).
3407 This means that we don't have writable Data or BSS segments, and BSS
3408 is not initialized as zero. To be able to get a C environment working
3409 at all, we have to allocate at least a minimal stack. Implementation
3410 options for this are defined and restricted by the CPU used: Some CPU
3411 models provide on-chip memory (like the IMMR area on MPC8xx and
3412 MPC826x processors), on others (parts of) the data cache can be
3413 locked as (mis-) used as memory, etc.
3415 Chris Hallinan posted a good summary of these issues to the
3416 u-boot-users mailing list:
3418 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3419 From: "Chris Hallinan" <clh@net1plus.com>
3420 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3423 Correct me if I'm wrong, folks, but the way I understand it
3424 is this: Using DCACHE as initial RAM for Stack, etc, does not
3425 require any physical RAM backing up the cache. The cleverness
3426 is that the cache is being used as a temporary supply of
3427 necessary storage before the SDRAM controller is setup. It's
3428 beyond the scope of this list to expain the details, but you
3429 can see how this works by studying the cache architecture and
3430 operation in the architecture and processor-specific manuals.
3432 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3433 is another option for the system designer to use as an
3434 initial stack/ram area prior to SDRAM being available. Either
3435 option should work for you. Using CS 4 should be fine if your
3436 board designers haven't used it for something that would
3437 cause you grief during the initial boot! It is frequently not
3440 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3441 with your processor/board/system design. The default value
3442 you will find in any recent u-boot distribution in
3443 walnut.h should work for you. I'd set it to a value larger
3444 than your SDRAM module. If you have a 64MB SDRAM module, set
3445 it above 400_0000. Just make sure your board has no resources
3446 that are supposed to respond to that address! That code in
3447 start.S has been around a while and should work as is when
3448 you get the config right.
3453 It is essential to remember this, since it has some impact on the C
3454 code for the initialization procedures:
3456 * Initialized global data (data segment) is read-only. Do not attempt
3459 * Do not use any unitialized global data (or implicitely initialized
3460 as zero data - BSS segment) at all - this is undefined, initiali-
3461 zation is performed later (when relocating to RAM).
3463 * Stack space is very limited. Avoid big data buffers or things like
3466 Having only the stack as writable memory limits means we cannot use
3467 normal global data to share information beween the code. But it
3468 turned out that the implementation of U-Boot can be greatly
3469 simplified by making a global data structure (gd_t) available to all
3470 functions. We could pass a pointer to this data as argument to _all_
3471 functions, but this would bloat the code. Instead we use a feature of
3472 the GCC compiler (Global Register Variables) to share the data: we
3473 place a pointer (gd) to the global data into a register which we
3474 reserve for this purpose.
3476 When choosing a register for such a purpose we are restricted by the
3477 relevant (E)ABI specifications for the current architecture, and by
3478 GCC's implementation.
3480 For PowerPC, the following registers have specific use:
3483 R3-R4: parameter passing and return values
3484 R5-R10: parameter passing
3485 R13: small data area pointer
3489 (U-Boot also uses R14 as internal GOT pointer.)
3491 ==> U-Boot will use R29 to hold a pointer to the global data
3493 Note: on PPC, we could use a static initializer (since the
3494 address of the global data structure is known at compile time),
3495 but it turned out that reserving a register results in somewhat
3496 smaller code - although the code savings are not that big (on
3497 average for all boards 752 bytes for the whole U-Boot image,
3498 624 text + 127 data).
3500 On ARM, the following registers are used:
3502 R0: function argument word/integer result
3503 R1-R3: function argument word
3505 R10: stack limit (used only if stack checking if enabled)
3506 R11: argument (frame) pointer
3507 R12: temporary workspace
3510 R15: program counter
3512 ==> U-Boot will use R8 to hold a pointer to the global data
3514 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3515 or current versions of GCC may "optimize" the code too much.
3520 U-Boot runs in system state and uses physical addresses, i.e. the
3521 MMU is not used either for address mapping nor for memory protection.
3523 The available memory is mapped to fixed addresses using the memory
3524 controller. In this process, a contiguous block is formed for each
3525 memory type (Flash, SDRAM, SRAM), even when it consists of several
3526 physical memory banks.
3528 U-Boot is installed in the first 128 kB of the first Flash bank (on
3529 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3530 booting and sizing and initializing DRAM, the code relocates itself
3531 to the upper end of DRAM. Immediately below the U-Boot code some
3532 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3533 configuration setting]. Below that, a structure with global Board
3534 Info data is placed, followed by the stack (growing downward).
3536 Additionally, some exception handler code is copied to the low 8 kB
3537 of DRAM (0x00000000 ... 0x00001FFF).
3539 So a typical memory configuration with 16 MB of DRAM could look like
3542 0x0000 0000 Exception Vector code
3545 0x0000 2000 Free for Application Use
3551 0x00FB FF20 Monitor Stack (Growing downward)
3552 0x00FB FFAC Board Info Data and permanent copy of global data
3553 0x00FC 0000 Malloc Arena
3556 0x00FE 0000 RAM Copy of Monitor Code
3557 ... eventually: LCD or video framebuffer
3558 ... eventually: pRAM (Protected RAM - unchanged by reset)
3559 0x00FF FFFF [End of RAM]
3562 System Initialization:
3563 ----------------------
3565 In the reset configuration, U-Boot starts at the reset entry point
3566 (on most PowerPC systens at address 0x00000100). Because of the reset
3567 configuration for CS0# this is a mirror of the onboard Flash memory.
3568 To be able to re-map memory U-Boot then jumps to its link address.
3569 To be able to implement the initialization code in C, a (small!)
3570 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3571 which provide such a feature like MPC8xx or MPC8260), or in a locked
3572 part of the data cache. After that, U-Boot initializes the CPU core,
3573 the caches and the SIU.
3575 Next, all (potentially) available memory banks are mapped using a
3576 preliminary mapping. For example, we put them on 512 MB boundaries
3577 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3578 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3579 programmed for SDRAM access. Using the temporary configuration, a
3580 simple memory test is run that determines the size of the SDRAM
3583 When there is more than one SDRAM bank, and the banks are of
3584 different size, the largest is mapped first. For equal size, the first
3585 bank (CS2#) is mapped first. The first mapping is always for address
3586 0x00000000, with any additional banks following immediately to create
3587 contiguous memory starting from 0.
3589 Then, the monitor installs itself at the upper end of the SDRAM area
3590 and allocates memory for use by malloc() and for the global Board
3591 Info data; also, the exception vector code is copied to the low RAM
3592 pages, and the final stack is set up.
3594 Only after this relocation will you have a "normal" C environment;
3595 until that you are restricted in several ways, mostly because you are
3596 running from ROM, and because the code will have to be relocated to a
3600 U-Boot Porting Guide:
3601 ----------------------
3603 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3607 int main (int argc, char *argv[])
3609 sighandler_t no_more_time;
3611 signal (SIGALRM, no_more_time);
3612 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3614 if (available_money > available_manpower) {
3615 pay consultant to port U-Boot;
3619 Download latest U-Boot source;
3621 Subscribe to u-boot-users mailing list;
3624 email ("Hi, I am new to U-Boot, how do I get started?");
3628 Read the README file in the top level directory;
3629 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3630 Read the source, Luke;
3633 if (available_money > toLocalCurrency ($2500)) {
3636 Add a lot of aggravation and time;
3639 Create your own board support subdirectory;
3641 Create your own board config file;
3645 Add / modify source code;
3649 email ("Hi, I am having problems...");
3651 Send patch file to Wolfgang;
3656 void no_more_time (int sig)
3665 All contributions to U-Boot should conform to the Linux kernel
3666 coding style; see the file "Documentation/CodingStyle" and the script
3667 "scripts/Lindent" in your Linux kernel source directory. In sources
3668 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3669 spaces before parameters to function calls) is actually used.
3671 Source files originating from a different project (for example the
3672 MTD subsystem) are generally exempt from these guidelines and are not
3673 reformated to ease subsequent migration to newer versions of those
3676 Please note that U-Boot is implemented in C (and to some small parts in
3677 Assembler); no C++ is used, so please do not use C++ style comments (//)
3680 Please also stick to the following formatting rules:
3681 - remove any trailing white space
3682 - use TAB characters for indentation, not spaces
3683 - make sure NOT to use DOS '\r\n' line feeds
3684 - do not add more than 2 empty lines to source files
3685 - do not add trailing empty lines to source files
3687 Submissions which do not conform to the standards may be returned
3688 with a request to reformat the changes.
3694 Since the number of patches for U-Boot is growing, we need to
3695 establish some rules. Submissions which do not conform to these rules
3696 may be rejected, even when they contain important and valuable stuff.
3698 Patches shall be sent to the u-boot-users mailing list.
3700 When you send a patch, please include the following information with
3703 * For bug fixes: a description of the bug and how your patch fixes
3704 this bug. Please try to include a way of demonstrating that the
3705 patch actually fixes something.
3707 * For new features: a description of the feature and your
3710 * A CHANGELOG entry as plaintext (separate from the patch)
3712 * For major contributions, your entry to the CREDITS file
3714 * When you add support for a new board, don't forget to add this
3715 board to the MAKEALL script, too.
3717 * If your patch adds new configuration options, don't forget to
3718 document these in the README file.
3720 * The patch itself. If you are accessing the CVS repository use "cvs
3721 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3722 version of diff does not support these options, then get the latest
3723 version of GNU diff.
3725 The current directory when running this command shall be the top
3726 level directory of the U-Boot source tree, or it's parent directory
3727 (i. e. please make sure that your patch includes sufficient
3728 directory information for the affected files).
3730 We accept patches as plain text, MIME attachments or as uuencoded
3733 * If one logical set of modifications affects or creates several
3734 files, all these changes shall be submitted in a SINGLE patch file.
3736 * Changesets that contain different, unrelated modifications shall be
3737 submitted as SEPARATE patches, one patch per changeset.
3742 * Before sending the patch, run the MAKEALL script on your patched
3743 source tree and make sure that no errors or warnings are reported
3744 for any of the boards.
3746 * Keep your modifications to the necessary minimum: A patch
3747 containing several unrelated changes or arbitrary reformats will be
3748 returned with a request to re-formatting / split it.
3750 * If you modify existing code, make sure that your new code does not
3751 add to the memory footprint of the code ;-) Small is beautiful!
3752 When adding new features, these should compile conditionally only
3753 (using #ifdef), and the resulting code with the new feature
3754 disabled must not need more memory than the old code without your
3757 * Remember that there is a size limit of 40 kB per message on the
3758 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob