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 CONFIG_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 CONFIG_CMD_KGDB is defined)
650 Select one of the baudrates listed in
651 CFG_BAUDRATE_TABLE, see below.
654 Monitor commands can be included or excluded
655 from the build by using the #include files
656 "config_cmd_all.h" and #undef'ing unwanted
657 commands, or using "config_cmd_default.h"
658 and augmenting with additional #define's
661 The default command configuration includes all commands
662 except those marked below with a "*".
664 CONFIG_CMD_ASKENV * ask for env variable
665 CONFIG_CMD_AUTOSCRIPT Autoscript Support
666 CONFIG_CMD_BDI bdinfo
667 CONFIG_CMD_BEDBUG * Include BedBug Debugger
668 CONFIG_CMD_BMP * BMP support
669 CONFIG_CMD_BSP * Board specific commands
670 CONFIG_CMD_BOOTD bootd
671 CONFIG_CMD_CACHE * icache, dcache
672 CONFIG_CMD_CONSOLE coninfo
673 CONFIG_CMD_DATE * support for RTC, date/time...
674 CONFIG_CMD_DHCP * DHCP support
675 CONFIG_CMD_DIAG * Diagnostics
676 CONFIG_CMD_DOC * Disk-On-Chip Support
677 CONFIG_CMD_DTT * Digital Therm and Thermostat
678 CONFIG_CMD_ECHO echo arguments
679 CONFIG_CMD_EEPROM * EEPROM read/write support
680 CONFIG_CMD_ELF * bootelf, bootvx
681 CONFIG_CMD_ENV saveenv
682 CONFIG_CMD_FDC * Floppy Disk Support
683 CONFIG_CMD_FAT * FAT partition support
684 CONFIG_CMD_FDOS * Dos diskette Support
685 CONFIG_CMD_FLASH flinfo, erase, protect
686 CONFIG_CMD_FPGA FPGA device initialization support
687 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
688 CONFIG_CMD_I2C * I2C serial bus support
689 CONFIG_CMD_IDE * IDE harddisk support
690 CONFIG_CMD_IMI iminfo
691 CONFIG_CMD_IMLS List all found images
692 CONFIG_CMD_IMMAP * IMMR dump support
693 CONFIG_CMD_IRQ * irqinfo
694 CONFIG_CMD_ITEST Integer/string test of 2 values
695 CONFIG_CMD_JFFS2 * JFFS2 Support
696 CONFIG_CMD_KGDB * kgdb
697 CONFIG_CMD_LOADB loadb
698 CONFIG_CMD_LOADS loads
699 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
701 CONFIG_CMD_MISC Misc functions like sleep etc
702 CONFIG_CMD_MMC * MMC memory mapped support
703 CONFIG_CMD_MII * MII utility commands
704 CONFIG_CMD_NAND * NAND support
705 CONFIG_CMD_NET bootp, tftpboot, rarpboot
706 CONFIG_CMD_PCI * pciinfo
707 CONFIG_CMD_PCMCIA * PCMCIA support
708 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
710 CONFIG_CMD_PORTIO * Port I/O
711 CONFIG_CMD_REGINFO * Register dump
712 CONFIG_CMD_RUN run command in env variable
713 CONFIG_CMD_SAVES * save S record dump
714 CONFIG_CMD_SCSI * SCSI Support
715 CONFIG_CMD_SDRAM * print SDRAM configuration information
716 (requires CONFIG_CMD_I2C)
717 CONFIG_CMD_SETGETDCR Support for DCR Register access
719 CONFIG_CMD_SPI * SPI serial bus support
720 CONFIG_CMD_USB * USB support
721 CONFIG_CMD_VFD * VFD support (TRAB)
722 CONFIG_CMD_BSP * Board SPecific functions
723 CONFIG_CMD_CDP * Cisco Discover Protocol support
724 CONFIG_CMD_FSL * Microblaze FSL support
727 EXAMPLE: If you want all functions except of network
728 support you can write:
730 #include "config_cmd_all.h"
731 #undef CONFIG_CMD_NET
734 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
736 Note: Don't enable the "icache" and "dcache" commands
737 (configuration option CONFIG_CMD_CACHE) unless you know
738 what you (and your U-Boot users) are doing. Data
739 cache cannot be enabled on systems like the 8xx or
740 8260 (where accesses to the IMMR region must be
741 uncached), and it cannot be disabled on all other
742 systems where we (mis-) use the data cache to hold an
743 initial stack and some data.
746 XXX - this list needs to get updated!
750 If this variable is defined, it enables watchdog
751 support. There must be support in the platform specific
752 code for a watchdog. For the 8xx and 8260 CPUs, the
753 SIU Watchdog feature is enabled in the SYPCR
757 CONFIG_VERSION_VARIABLE
758 If this variable is defined, an environment variable
759 named "ver" is created by U-Boot showing the U-Boot
760 version as printed by the "version" command.
761 This variable is readonly.
765 When CONFIG_CMD_DATE is selected, the type of the RTC
766 has to be selected, too. Define exactly one of the
769 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
770 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
771 CONFIG_RTC_MC146818 - use MC146818 RTC
772 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
773 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
774 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
775 CONFIG_RTC_DS164x - use Dallas DS164x RTC
776 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
778 Note that if the RTC uses I2C, then the I2C interface
779 must also be configured. See I2C Support, below.
783 When CONFIG_TIMESTAMP is selected, the timestamp
784 (date and time) of an image is printed by image
785 commands like bootm or iminfo. This option is
786 automatically enabled when you select CONFIG_CMD_DATE .
789 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
790 and/or CONFIG_ISO_PARTITION
792 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
793 CONFIG_CMD_SCSI) you must configure support for at least
794 one partition type as well.
797 CONFIG_IDE_RESET_ROUTINE - this is defined in several
798 board configurations files but used nowhere!
800 CONFIG_IDE_RESET - is this is defined, IDE Reset will
801 be performed by calling the function
802 ide_set_reset(int reset)
803 which has to be defined in a board specific file
808 Set this to enable ATAPI support.
813 Set this to enable support for disks larger than 137GB
814 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
815 Whithout these , LBA48 support uses 32bit variables and will 'only'
816 support disks up to 2.1TB.
819 When enabled, makes the IDE subsystem use 64bit sector addresses.
823 At the moment only there is only support for the
824 SYM53C8XX SCSI controller; define
825 CONFIG_SCSI_SYM53C8XX to enable it.
827 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
828 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
829 CFG_SCSI_MAX_LUN] can be adjusted to define the
830 maximum numbers of LUNs, SCSI ID's and target
832 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
834 - NETWORK Support (PCI):
836 Support for Intel 8254x gigabit chips.
839 Support for Intel 82557/82559/82559ER chips.
840 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
841 write routine for first time initialisation.
844 Support for Digital 2114x chips.
845 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
846 modem chip initialisation (KS8761/QS6611).
849 Support for National dp83815 chips.
852 Support for National dp8382[01] gigabit chips.
854 - NETWORK Support (other):
856 CONFIG_DRIVER_LAN91C96
857 Support for SMSC's LAN91C96 chips.
860 Define this to hold the physical address
861 of the LAN91C96's I/O space
863 CONFIG_LAN91C96_USE_32_BIT
864 Define this to enable 32 bit addressing
866 CONFIG_DRIVER_SMC91111
867 Support for SMSC's LAN91C111 chip
870 Define this to hold the physical address
871 of the device (I/O space)
873 CONFIG_SMC_USE_32_BIT
874 Define this if data bus is 32 bits
876 CONFIG_SMC_USE_IOFUNCS
877 Define this to use i/o functions instead of macros
878 (some hardware wont work with macros)
881 At the moment only the UHCI host controller is
882 supported (PIP405, MIP405, MPC5200); define
883 CONFIG_USB_UHCI to enable it.
884 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
885 and define CONFIG_USB_STORAGE to enable the USB
888 Supported are USB Keyboards and USB Floppy drives
890 MPC5200 USB requires additional defines:
892 for 528 MHz Clock: 0x0001bbbb
894 for differential drivers: 0x00001000
895 for single ended drivers: 0x00005000
899 The MMC controller on the Intel PXA is supported. To
900 enable this define CONFIG_MMC. The MMC can be
901 accessed from the boot prompt by mapping the device
902 to physical memory similar to flash. Command line is
903 enabled with CONFIG_CMD_MMC. The MMC driver also works with
904 the FAT fs. This is enabled with CONFIG_CMD_FAT.
906 - Journaling Flash filesystem support:
907 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
908 CONFIG_JFFS2_NAND_DEV
909 Define these for a default partition on a NAND device
911 CFG_JFFS2_FIRST_SECTOR,
912 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
913 Define these for a default partition on a NOR device
916 Define this to create an own partition. You have to provide a
917 function struct part_info* jffs2_part_info(int part_num)
919 If you define only one JFFS2 partition you may also want to
920 #define CFG_JFFS_SINGLE_PART 1
921 to disable the command chpart. This is the default when you
922 have not defined a custom partition
927 Define this to enable standard (PC-Style) keyboard
931 Standard PC keyboard driver with US (is default) and
932 GERMAN key layout (switch via environment 'keymap=de') support.
933 Export function i8042_kbd_init, i8042_tstc and i8042_getc
934 for cfb_console. Supports cursor blinking.
939 Define this to enable video support (for output to
944 Enable Chips & Technologies 69000 Video chip
946 CONFIG_VIDEO_SMI_LYNXEM
947 Enable Silicon Motion SMI 712/710/810 Video chip. The
948 video output is selected via environment 'videoout'
949 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
952 For the CT69000 and SMI_LYNXEM drivers, videomode is
953 selected via environment 'videomode'. Two diferent ways
955 - "videomode=num" 'num' is a standard LiLo mode numbers.
956 Following standard modes are supported (* is default):
958 Colors 640x480 800x600 1024x768 1152x864 1280x1024
959 -------------+---------------------------------------------
960 8 bits | 0x301* 0x303 0x305 0x161 0x307
961 15 bits | 0x310 0x313 0x316 0x162 0x319
962 16 bits | 0x311 0x314 0x317 0x163 0x31A
963 24 bits | 0x312 0x315 0x318 ? 0x31B
964 -------------+---------------------------------------------
965 (i.e. setenv videomode 317; saveenv; reset;)
967 - "videomode=bootargs" all the video parameters are parsed
968 from the bootargs. (See drivers/videomodes.c)
971 CONFIG_VIDEO_SED13806
972 Enable Epson SED13806 driver. This driver supports 8bpp
973 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
974 or CONFIG_VIDEO_SED13806_16BPP
979 Define this to enable a custom keyboard support.
980 This simply calls drv_keyboard_init() which must be
981 defined in your board-specific files.
982 The only board using this so far is RBC823.
984 - LCD Support: CONFIG_LCD
986 Define this to enable LCD support (for output to LCD
987 display); also select one of the supported displays
988 by defining one of these:
990 CONFIG_NEC_NL6448AC33:
992 NEC NL6448AC33-18. Active, color, single scan.
994 CONFIG_NEC_NL6448BC20
996 NEC NL6448BC20-08. 6.5", 640x480.
997 Active, color, single scan.
999 CONFIG_NEC_NL6448BC33_54
1001 NEC NL6448BC33-54. 10.4", 640x480.
1002 Active, color, single scan.
1006 Sharp 320x240. Active, color, single scan.
1007 It isn't 16x9, and I am not sure what it is.
1009 CONFIG_SHARP_LQ64D341
1011 Sharp LQ64D341 display, 640x480.
1012 Active, color, single scan.
1016 HLD1045 display, 640x480.
1017 Active, color, single scan.
1021 Optrex CBL50840-2 NF-FW 99 22 M5
1023 Hitachi LMG6912RPFC-00T
1027 320x240. Black & white.
1029 Normally display is black on white background; define
1030 CFG_WHITE_ON_BLACK to get it inverted.
1032 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1034 If this option is set, the environment is checked for
1035 a variable "splashimage". If found, the usual display
1036 of logo, copyright and system information on the LCD
1037 is suppressed and the BMP image at the address
1038 specified in "splashimage" is loaded instead. The
1039 console is redirected to the "nulldev", too. This
1040 allows for a "silent" boot where a splash screen is
1041 loaded very quickly after power-on.
1043 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1045 If this option is set, additionally to standard BMP
1046 images, gzipped BMP images can be displayed via the
1047 splashscreen support or the bmp command.
1049 - Compression support:
1052 If this option is set, support for bzip2 compressed
1053 images is included. If not, only uncompressed and gzip
1054 compressed images are supported.
1056 NOTE: the bzip2 algorithm requires a lot of RAM, so
1057 the malloc area (as defined by CFG_MALLOC_LEN) should
1063 The address of PHY on MII bus.
1065 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1067 The clock frequency of the MII bus
1071 If this option is set, support for speed/duplex
1072 detection of Gigabit PHY is included.
1074 CONFIG_PHY_RESET_DELAY
1076 Some PHY like Intel LXT971A need extra delay after
1077 reset before any MII register access is possible.
1078 For such PHY, set this option to the usec delay
1079 required. (minimum 300usec for LXT971A)
1081 CONFIG_PHY_CMD_DELAY (ppc4xx)
1083 Some PHY like Intel LXT971A need extra delay after
1084 command issued before MII status register can be read
1091 Define a default value for ethernet address to use
1092 for the respective ethernet interface, in case this
1093 is not determined automatically.
1098 Define a default value for the IP address to use for
1099 the default ethernet interface, in case this is not
1100 determined through e.g. bootp.
1102 - Server IP address:
1105 Defines a default value for theIP address of a TFTP
1106 server to contact when using the "tftboot" command.
1108 - BOOTP Recovery Mode:
1109 CONFIG_BOOTP_RANDOM_DELAY
1111 If you have many targets in a network that try to
1112 boot using BOOTP, you may want to avoid that all
1113 systems send out BOOTP requests at precisely the same
1114 moment (which would happen for instance at recovery
1115 from a power failure, when all systems will try to
1116 boot, thus flooding the BOOTP server. Defining
1117 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1118 inserted before sending out BOOTP requests. The
1119 following delays are insterted then:
1121 1st BOOTP request: delay 0 ... 1 sec
1122 2nd BOOTP request: delay 0 ... 2 sec
1123 3rd BOOTP request: delay 0 ... 4 sec
1125 BOOTP requests: delay 0 ... 8 sec
1127 - DHCP Advanced Options:
1130 You can fine tune the DHCP functionality by adding
1131 these flags to the CONFIG_BOOTP_MASK define:
1133 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1134 serverip from a DHCP server, it is possible that more
1135 than one DNS serverip is offered to the client.
1136 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1137 serverip will be stored in the additional environment
1138 variable "dnsip2". The first DNS serverip is always
1139 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1140 is added to the CONFIG_BOOTP_MASK.
1142 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1143 to do a dynamic update of a DNS server. To do this, they
1144 need the hostname of the DHCP requester.
1145 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1146 CONFIG_BOOTP_MASK, the content of the "hostname"
1147 environment variable is passed as option 12 to
1151 CONFIG_CDP_DEVICE_ID
1153 The device id used in CDP trigger frames.
1155 CONFIG_CDP_DEVICE_ID_PREFIX
1157 A two character string which is prefixed to the MAC address
1162 A printf format string which contains the ascii name of
1163 the port. Normally is set to "eth%d" which sets
1164 eth0 for the first ethernet, eth1 for the second etc.
1166 CONFIG_CDP_CAPABILITIES
1168 A 32bit integer which indicates the device capabilities;
1169 0x00000010 for a normal host which does not forwards.
1173 An ascii string containing the version of the software.
1177 An ascii string containing the name of the platform.
1181 A 32bit integer sent on the trigger.
1183 CONFIG_CDP_POWER_CONSUMPTION
1185 A 16bit integer containing the power consumption of the
1186 device in .1 of milliwatts.
1188 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1190 A byte containing the id of the VLAN.
1192 - Status LED: CONFIG_STATUS_LED
1194 Several configurations allow to display the current
1195 status using a LED. For instance, the LED will blink
1196 fast while running U-Boot code, stop blinking as
1197 soon as a reply to a BOOTP request was received, and
1198 start blinking slow once the Linux kernel is running
1199 (supported by a status LED driver in the Linux
1200 kernel). Defining CONFIG_STATUS_LED enables this
1203 - CAN Support: CONFIG_CAN_DRIVER
1205 Defining CONFIG_CAN_DRIVER enables CAN driver support
1206 on those systems that support this (optional)
1207 feature, like the TQM8xxL modules.
1209 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1211 These enable I2C serial bus commands. Defining either of
1212 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1213 include the appropriate I2C driver for the selected cpu.
1215 This will allow you to use i2c commands at the u-boot
1216 command line (as long as you set CONFIG_CMD_I2C in
1217 CONFIG_COMMANDS) and communicate with i2c based realtime
1218 clock chips. See common/cmd_i2c.c for a description of the
1219 command line interface.
1221 CONFIG_I2C_CMD_TREE is a recommended option that places
1222 all I2C commands under a single 'i2c' root command. The
1223 older 'imm', 'imd', 'iprobe' etc. commands are considered
1224 deprecated and may disappear in the future.
1226 CONFIG_HARD_I2C selects a hardware I2C controller.
1228 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1229 bit-banging) driver instead of CPM or similar hardware
1232 There are several other quantities that must also be
1233 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1235 In both cases you will need to define CFG_I2C_SPEED
1236 to be the frequency (in Hz) at which you wish your i2c bus
1237 to run and CFG_I2C_SLAVE to be the address of this node (ie
1238 the cpu's i2c node address).
1240 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1241 sets the cpu up as a master node and so its address should
1242 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1243 p.16-473). So, set CFG_I2C_SLAVE to 0.
1245 That's all that's required for CONFIG_HARD_I2C.
1247 If you use the software i2c interface (CONFIG_SOFT_I2C)
1248 then the following macros need to be defined (examples are
1249 from include/configs/lwmon.h):
1253 (Optional). Any commands necessary to enable the I2C
1254 controller or configure ports.
1256 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1260 (Only for MPC8260 CPU). The I/O port to use (the code
1261 assumes both bits are on the same port). Valid values
1262 are 0..3 for ports A..D.
1266 The code necessary to make the I2C data line active
1267 (driven). If the data line is open collector, this
1270 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1274 The code necessary to make the I2C data line tri-stated
1275 (inactive). If the data line is open collector, this
1278 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1282 Code that returns TRUE if the I2C data line is high,
1285 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1289 If <bit> is TRUE, sets the I2C data line high. If it
1290 is FALSE, it clears it (low).
1292 eg: #define I2C_SDA(bit) \
1293 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1294 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1298 If <bit> is TRUE, sets the I2C clock line high. If it
1299 is FALSE, it clears it (low).
1301 eg: #define I2C_SCL(bit) \
1302 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1303 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1307 This delay is invoked four times per clock cycle so this
1308 controls the rate of data transfer. The data rate thus
1309 is 1 / (I2C_DELAY * 4). Often defined to be something
1312 #define I2C_DELAY udelay(2)
1316 When a board is reset during an i2c bus transfer
1317 chips might think that the current transfer is still
1318 in progress. On some boards it is possible to access
1319 the i2c SCLK line directly, either by using the
1320 processor pin as a GPIO or by having a second pin
1321 connected to the bus. If this option is defined a
1322 custom i2c_init_board() routine in boards/xxx/board.c
1323 is run early in the boot sequence.
1325 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1327 This option enables configuration of bi_iic_fast[] flags
1328 in u-boot bd_info structure based on u-boot environment
1329 variable "i2cfast". (see also i2cfast)
1331 CONFIG_I2C_MULTI_BUS
1333 This option allows the use of multiple I2C buses, each of which
1334 must have a controller. At any point in time, only one bus is
1335 active. To switch to a different bus, use the 'i2c dev' command.
1336 Note that bus numbering is zero-based.
1340 This option specifies a list of I2C devices that will be skipped
1341 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1342 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1343 pairs. Otherwise, specify a 1D array of device addresses
1346 #undef CONFIG_I2C_MULTI_BUS
1347 #define CFG_I2C_NOPROBES {0x50,0x68}
1349 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1351 #define CONFIG_I2C_MULTI_BUS
1352 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1354 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1358 If defined, then this indicates the I2C bus number for DDR SPD.
1359 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1363 If defined, then this indicates the I2C bus number for the RTC.
1364 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1368 If defined, then this indicates the I2C bus number for the DTT.
1369 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1373 Define this option if you want to use Freescale's I2C driver in
1377 - SPI Support: CONFIG_SPI
1379 Enables SPI driver (so far only tested with
1380 SPI EEPROM, also an instance works with Crystal A/D and
1381 D/As on the SACSng board)
1385 Enables extended (16-bit) SPI EEPROM addressing.
1386 (symmetrical to CONFIG_I2C_X)
1390 Enables a software (bit-bang) SPI driver rather than
1391 using hardware support. This is a general purpose
1392 driver that only requires three general I/O port pins
1393 (two outputs, one input) to function. If this is
1394 defined, the board configuration must define several
1395 SPI configuration items (port pins to use, etc). For
1396 an example, see include/configs/sacsng.h.
1398 - FPGA Support: CONFIG_FPGA_COUNT
1400 Specify the number of FPGA devices to support.
1404 Used to specify the types of FPGA devices. For example,
1405 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1407 CFG_FPGA_PROG_FEEDBACK
1409 Enable printing of hash marks during FPGA configuration.
1413 Enable checks on FPGA configuration interface busy
1414 status by the configuration function. This option
1415 will require a board or device specific function to
1420 If defined, a function that provides delays in the FPGA
1421 configuration driver.
1423 CFG_FPGA_CHECK_CTRLC
1424 Allow Control-C to interrupt FPGA configuration
1426 CFG_FPGA_CHECK_ERROR
1428 Check for configuration errors during FPGA bitfile
1429 loading. For example, abort during Virtex II
1430 configuration if the INIT_B line goes low (which
1431 indicated a CRC error).
1435 Maximum time to wait for the INIT_B line to deassert
1436 after PROB_B has been deasserted during a Virtex II
1437 FPGA configuration sequence. The default time is 500
1442 Maximum time to wait for BUSY to deassert during
1443 Virtex II FPGA configuration. The default is 5 mS.
1445 CFG_FPGA_WAIT_CONFIG
1447 Time to wait after FPGA configuration. The default is
1450 - Configuration Management:
1453 If defined, this string will be added to the U-Boot
1454 version information (U_BOOT_VERSION)
1456 - Vendor Parameter Protection:
1458 U-Boot considers the values of the environment
1459 variables "serial#" (Board Serial Number) and
1460 "ethaddr" (Ethernet Address) to be parameters that
1461 are set once by the board vendor / manufacturer, and
1462 protects these variables from casual modification by
1463 the user. Once set, these variables are read-only,
1464 and write or delete attempts are rejected. You can
1465 change this behviour:
1467 If CONFIG_ENV_OVERWRITE is #defined in your config
1468 file, the write protection for vendor parameters is
1469 completely disabled. Anybody can change or delete
1472 Alternatively, if you #define _both_ CONFIG_ETHADDR
1473 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1474 ethernet address is installed in the environment,
1475 which can be changed exactly ONCE by the user. [The
1476 serial# is unaffected by this, i. e. it remains
1482 Define this variable to enable the reservation of
1483 "protected RAM", i. e. RAM which is not overwritten
1484 by U-Boot. Define CONFIG_PRAM to hold the number of
1485 kB you want to reserve for pRAM. You can overwrite
1486 this default value by defining an environment
1487 variable "pram" to the number of kB you want to
1488 reserve. Note that the board info structure will
1489 still show the full amount of RAM. If pRAM is
1490 reserved, a new environment variable "mem" will
1491 automatically be defined to hold the amount of
1492 remaining RAM in a form that can be passed as boot
1493 argument to Linux, for instance like that:
1495 setenv bootargs ... mem=\${mem}
1498 This way you can tell Linux not to use this memory,
1499 either, which results in a memory region that will
1500 not be affected by reboots.
1502 *WARNING* If your board configuration uses automatic
1503 detection of the RAM size, you must make sure that
1504 this memory test is non-destructive. So far, the
1505 following board configurations are known to be
1508 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1509 HERMES, IP860, RPXlite, LWMON, LANTEC,
1510 PCU_E, FLAGADM, TQM8260
1515 Define this variable to stop the system in case of a
1516 fatal error, so that you have to reset it manually.
1517 This is probably NOT a good idea for an embedded
1518 system where you want to system to reboot
1519 automatically as fast as possible, but it may be
1520 useful during development since you can try to debug
1521 the conditions that lead to the situation.
1523 CONFIG_NET_RETRY_COUNT
1525 This variable defines the number of retries for
1526 network operations like ARP, RARP, TFTP, or BOOTP
1527 before giving up the operation. If not defined, a
1528 default value of 5 is used.
1530 - Command Interpreter:
1531 CONFIG_AUTO_COMPLETE
1533 Enable auto completion of commands using TAB.
1535 Note that this feature has NOT been implemented yet
1536 for the "hush" shell.
1541 Define this variable to enable the "hush" shell (from
1542 Busybox) as command line interpreter, thus enabling
1543 powerful command line syntax like
1544 if...then...else...fi conditionals or `&&' and '||'
1545 constructs ("shell scripts").
1547 If undefined, you get the old, much simpler behaviour
1548 with a somewhat smaller memory footprint.
1553 This defines the secondary prompt string, which is
1554 printed when the command interpreter needs more input
1555 to complete a command. Usually "> ".
1559 In the current implementation, the local variables
1560 space and global environment variables space are
1561 separated. Local variables are those you define by
1562 simply typing `name=value'. To access a local
1563 variable later on, you have write `$name' or
1564 `${name}'; to execute the contents of a variable
1565 directly type `$name' at the command prompt.
1567 Global environment variables are those you use
1568 setenv/printenv to work with. To run a command stored
1569 in such a variable, you need to use the run command,
1570 and you must not use the '$' sign to access them.
1572 To store commands and special characters in a
1573 variable, please use double quotation marks
1574 surrounding the whole text of the variable, instead
1575 of the backslashes before semicolons and special
1578 - Commandline Editing and History:
1579 CONFIG_CMDLINE_EDITING
1581 Enable editiong and History functions for interactive
1582 commandline input operations
1584 - Default Environment:
1585 CONFIG_EXTRA_ENV_SETTINGS
1587 Define this to contain any number of null terminated
1588 strings (variable = value pairs) that will be part of
1589 the default environment compiled into the boot image.
1591 For example, place something like this in your
1592 board's config file:
1594 #define CONFIG_EXTRA_ENV_SETTINGS \
1598 Warning: This method is based on knowledge about the
1599 internal format how the environment is stored by the
1600 U-Boot code. This is NOT an official, exported
1601 interface! Although it is unlikely that this format
1602 will change soon, there is no guarantee either.
1603 You better know what you are doing here.
1605 Note: overly (ab)use of the default environment is
1606 discouraged. Make sure to check other ways to preset
1607 the environment like the autoscript function or the
1610 - DataFlash Support:
1611 CONFIG_HAS_DATAFLASH
1613 Defining this option enables DataFlash features and
1614 allows to read/write in Dataflash via the standard
1617 - SystemACE Support:
1620 Adding this option adds support for Xilinx SystemACE
1621 chips attached via some sort of local bus. The address
1622 of the chip must alsh be defined in the
1623 CFG_SYSTEMACE_BASE macro. For example:
1625 #define CONFIG_SYSTEMACE
1626 #define CFG_SYSTEMACE_BASE 0xf0000000
1628 When SystemACE support is added, the "ace" device type
1629 becomes available to the fat commands, i.e. fatls.
1631 - TFTP Fixed UDP Port:
1634 If this is defined, the environment variable tftpsrcp
1635 is used to supply the TFTP UDP source port value.
1636 If tftpsrcp isn't defined, the normal pseudo-random port
1637 number generator is used.
1639 Also, the environment variable tftpdstp is used to supply
1640 the TFTP UDP destination port value. If tftpdstp isn't
1641 defined, the normal port 69 is used.
1643 The purpose for tftpsrcp is to allow a TFTP server to
1644 blindly start the TFTP transfer using the pre-configured
1645 target IP address and UDP port. This has the effect of
1646 "punching through" the (Windows XP) firewall, allowing
1647 the remainder of the TFTP transfer to proceed normally.
1648 A better solution is to properly configure the firewall,
1649 but sometimes that is not allowed.
1651 - Show boot progress:
1652 CONFIG_SHOW_BOOT_PROGRESS
1654 Defining this option allows to add some board-
1655 specific code (calling a user-provided function
1656 "show_boot_progress(int)") that enables you to show
1657 the system's boot progress on some display (for
1658 example, some LED's) on your board. At the moment,
1659 the following checkpoints are implemented:
1662 1 common/cmd_bootm.c before attempting to boot an image
1663 -1 common/cmd_bootm.c Image header has bad magic number
1664 2 common/cmd_bootm.c Image header has correct magic number
1665 -2 common/cmd_bootm.c Image header has bad checksum
1666 3 common/cmd_bootm.c Image header has correct checksum
1667 -3 common/cmd_bootm.c Image data has bad checksum
1668 4 common/cmd_bootm.c Image data has correct checksum
1669 -4 common/cmd_bootm.c Image is for unsupported architecture
1670 5 common/cmd_bootm.c Architecture check OK
1671 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1672 6 common/cmd_bootm.c Image Type check OK
1673 -6 common/cmd_bootm.c gunzip uncompression error
1674 -7 common/cmd_bootm.c Unimplemented compression type
1675 7 common/cmd_bootm.c Uncompression OK
1676 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1677 8 common/cmd_bootm.c Image Type check OK
1678 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1679 9 common/cmd_bootm.c Start initial ramdisk verification
1680 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1681 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1682 10 common/cmd_bootm.c Ramdisk header is OK
1683 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1684 11 common/cmd_bootm.c Ramdisk data has correct checksum
1685 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1686 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1687 13 common/cmd_bootm.c Start multifile image verification
1688 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1689 15 common/cmd_bootm.c All preparation done, transferring control to OS
1691 -30 lib_ppc/board.c Fatal error, hang the system
1692 -31 post/post.c POST test failed, detected by post_output_backlog()
1693 -32 post/post.c POST test failed, detected by post_run_single()
1695 -1 common/cmd_doc.c Bad usage of "doc" command
1696 -1 common/cmd_doc.c No boot device
1697 -1 common/cmd_doc.c Unknown Chip ID on boot device
1698 -1 common/cmd_doc.c Read Error on boot device
1699 -1 common/cmd_doc.c Image header has bad magic number
1701 -1 common/cmd_ide.c Bad usage of "ide" command
1702 -1 common/cmd_ide.c No boot device
1703 -1 common/cmd_ide.c Unknown boot device
1704 -1 common/cmd_ide.c Unknown partition table
1705 -1 common/cmd_ide.c Invalid partition type
1706 -1 common/cmd_ide.c Read Error on boot device
1707 -1 common/cmd_ide.c Image header has bad magic number
1709 -1 common/cmd_nand.c Bad usage of "nand" command
1710 -1 common/cmd_nand.c No boot device
1711 -1 common/cmd_nand.c Unknown Chip ID on boot device
1712 -1 common/cmd_nand.c Read Error on boot device
1713 -1 common/cmd_nand.c Image header has bad magic number
1715 -1 common/env_common.c Environment has a bad CRC, using default
1721 [so far only for SMDK2400 and TRAB boards]
1723 - Modem support endable:
1724 CONFIG_MODEM_SUPPORT
1726 - RTS/CTS Flow control enable:
1729 - Modem debug support:
1730 CONFIG_MODEM_SUPPORT_DEBUG
1732 Enables debugging stuff (char screen[1024], dbg())
1733 for modem support. Useful only with BDI2000.
1735 - Interrupt support (PPC):
1737 There are common interrupt_init() and timer_interrupt()
1738 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1739 for cpu specific initialization. interrupt_init_cpu()
1740 should set decrementer_count to appropriate value. If
1741 cpu resets decrementer automatically after interrupt
1742 (ppc4xx) it should set decrementer_count to zero.
1743 timer_interrupt() calls timer_interrupt_cpu() for cpu
1744 specific handling. If board has watchdog / status_led
1745 / other_activity_monitor it works automatically from
1746 general timer_interrupt().
1750 In the target system modem support is enabled when a
1751 specific key (key combination) is pressed during
1752 power-on. Otherwise U-Boot will boot normally
1753 (autoboot). The key_pressed() fuction is called from
1754 board_init(). Currently key_pressed() is a dummy
1755 function, returning 1 and thus enabling modem
1758 If there are no modem init strings in the
1759 environment, U-Boot proceed to autoboot; the
1760 previous output (banner, info printfs) will be
1763 See also: doc/README.Modem
1766 Configuration Settings:
1767 -----------------------
1769 - CFG_LONGHELP: Defined when you want long help messages included;
1770 undefine this when you're short of memory.
1772 - CFG_PROMPT: This is what U-Boot prints on the console to
1773 prompt for user input.
1775 - CFG_CBSIZE: Buffer size for input from the Console
1777 - CFG_PBSIZE: Buffer size for Console output
1779 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1781 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1782 the application (usually a Linux kernel) when it is
1785 - CFG_BAUDRATE_TABLE:
1786 List of legal baudrate settings for this board.
1788 - CFG_CONSOLE_INFO_QUIET
1789 Suppress display of console information at boot.
1791 - CFG_CONSOLE_IS_IN_ENV
1792 If the board specific function
1793 extern int overwrite_console (void);
1794 returns 1, the stdin, stderr and stdout are switched to the
1795 serial port, else the settings in the environment are used.
1797 - CFG_CONSOLE_OVERWRITE_ROUTINE
1798 Enable the call to overwrite_console().
1800 - CFG_CONSOLE_ENV_OVERWRITE
1801 Enable overwrite of previous console environment settings.
1803 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1804 Begin and End addresses of the area used by the
1808 Enable an alternate, more extensive memory test.
1810 - CFG_MEMTEST_SCRATCH:
1811 Scratch address used by the alternate memory test
1812 You only need to set this if address zero isn't writeable
1814 - CFG_TFTP_LOADADDR:
1815 Default load address for network file downloads
1817 - CFG_LOADS_BAUD_CHANGE:
1818 Enable temporary baudrate change while serial download
1821 Physical start address of SDRAM. _Must_ be 0 here.
1824 Physical start address of Motherboard I/O (if using a
1828 Physical start address of Flash memory.
1831 Physical start address of boot monitor code (set by
1832 make config files to be same as the text base address
1833 (TEXT_BASE) used when linking) - same as
1834 CFG_FLASH_BASE when booting from flash.
1837 Size of memory reserved for monitor code, used to
1838 determine _at_compile_time_ (!) if the environment is
1839 embedded within the U-Boot image, or in a separate
1843 Size of DRAM reserved for malloc() use.
1846 Normally compressed uImages are limited to an
1847 uncompressed size of 8 MBytes. If this is not enough,
1848 you can define CFG_BOOTM_LEN in your board config file
1849 to adjust this setting to your needs.
1852 Maximum size of memory mapped by the startup code of
1853 the Linux kernel; all data that must be processed by
1854 the Linux kernel (bd_info, boot arguments, eventually
1855 initrd image) must be put below this limit.
1857 - CFG_MAX_FLASH_BANKS:
1858 Max number of Flash memory banks
1860 - CFG_MAX_FLASH_SECT:
1861 Max number of sectors on a Flash chip
1863 - CFG_FLASH_ERASE_TOUT:
1864 Timeout for Flash erase operations (in ms)
1866 - CFG_FLASH_WRITE_TOUT:
1867 Timeout for Flash write operations (in ms)
1869 - CFG_FLASH_LOCK_TOUT
1870 Timeout for Flash set sector lock bit operation (in ms)
1872 - CFG_FLASH_UNLOCK_TOUT
1873 Timeout for Flash clear lock bits operation (in ms)
1875 - CFG_FLASH_PROTECTION
1876 If defined, hardware flash sectors protection is used
1877 instead of U-Boot software protection.
1879 - CFG_DIRECT_FLASH_TFTP:
1881 Enable TFTP transfers directly to flash memory;
1882 without this option such a download has to be
1883 performed in two steps: (1) download to RAM, and (2)
1884 copy from RAM to flash.
1886 The two-step approach is usually more reliable, since
1887 you can check if the download worked before you erase
1888 the flash, but in some situations (when sytem RAM is
1889 too limited to allow for a tempory copy of the
1890 downloaded image) this option may be very useful.
1893 Define if the flash driver uses extra elements in the
1894 common flash structure for storing flash geometry.
1896 - CFG_FLASH_CFI_DRIVER
1897 This option also enables the building of the cfi_flash driver
1898 in the drivers directory
1900 - CFG_FLASH_QUIET_TEST
1901 If this option is defined, the common CFI flash doesn't
1902 print it's warning upon not recognized FLASH banks. This
1903 is useful, if some of the configured banks are only
1904 optionally available.
1906 - CFG_RX_ETH_BUFFER:
1907 Defines the number of ethernet receive buffers. On some
1908 ethernet controllers it is recommended to set this value
1909 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1910 buffers can be full shortly after enabling the interface
1911 on high ethernet traffic.
1912 Defaults to 4 if not defined.
1914 The following definitions that deal with the placement and management
1915 of environment data (variable area); in general, we support the
1916 following configurations:
1918 - CFG_ENV_IS_IN_FLASH:
1920 Define this if the environment is in flash memory.
1922 a) The environment occupies one whole flash sector, which is
1923 "embedded" in the text segment with the U-Boot code. This
1924 happens usually with "bottom boot sector" or "top boot
1925 sector" type flash chips, which have several smaller
1926 sectors at the start or the end. For instance, such a
1927 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1928 such a case you would place the environment in one of the
1929 4 kB sectors - with U-Boot code before and after it. With
1930 "top boot sector" type flash chips, you would put the
1931 environment in one of the last sectors, leaving a gap
1932 between U-Boot and the environment.
1936 Offset of environment data (variable area) to the
1937 beginning of flash memory; for instance, with bottom boot
1938 type flash chips the second sector can be used: the offset
1939 for this sector is given here.
1941 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1945 This is just another way to specify the start address of
1946 the flash sector containing the environment (instead of
1949 - CFG_ENV_SECT_SIZE:
1951 Size of the sector containing the environment.
1954 b) Sometimes flash chips have few, equal sized, BIG sectors.
1955 In such a case you don't want to spend a whole sector for
1960 If you use this in combination with CFG_ENV_IS_IN_FLASH
1961 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1962 of this flash sector for the environment. This saves
1963 memory for the RAM copy of the environment.
1965 It may also save flash memory if you decide to use this
1966 when your environment is "embedded" within U-Boot code,
1967 since then the remainder of the flash sector could be used
1968 for U-Boot code. It should be pointed out that this is
1969 STRONGLY DISCOURAGED from a robustness point of view:
1970 updating the environment in flash makes it always
1971 necessary to erase the WHOLE sector. If something goes
1972 wrong before the contents has been restored from a copy in
1973 RAM, your target system will be dead.
1975 - CFG_ENV_ADDR_REDUND
1978 These settings describe a second storage area used to hold
1979 a redundand copy of the environment data, so that there is
1980 a valid backup copy in case there is a power failure during
1981 a "saveenv" operation.
1983 BE CAREFUL! Any changes to the flash layout, and some changes to the
1984 source code will make it necessary to adapt <board>/u-boot.lds*
1988 - CFG_ENV_IS_IN_NVRAM:
1990 Define this if you have some non-volatile memory device
1991 (NVRAM, battery buffered SRAM) which you want to use for the
1997 These two #defines are used to determin the memory area you
1998 want to use for environment. It is assumed that this memory
1999 can just be read and written to, without any special
2002 BE CAREFUL! The first access to the environment happens quite early
2003 in U-Boot initalization (when we try to get the setting of for the
2004 console baudrate). You *MUST* have mappend your NVRAM area then, or
2007 Please note that even with NVRAM we still use a copy of the
2008 environment in RAM: we could work on NVRAM directly, but we want to
2009 keep settings there always unmodified except somebody uses "saveenv"
2010 to save the current settings.
2013 - CFG_ENV_IS_IN_EEPROM:
2015 Use this if you have an EEPROM or similar serial access
2016 device and a driver for it.
2021 These two #defines specify the offset and size of the
2022 environment area within the total memory of your EEPROM.
2024 - CFG_I2C_EEPROM_ADDR:
2025 If defined, specified the chip address of the EEPROM device.
2026 The default address is zero.
2028 - CFG_EEPROM_PAGE_WRITE_BITS:
2029 If defined, the number of bits used to address bytes in a
2030 single page in the EEPROM device. A 64 byte page, for example
2031 would require six bits.
2033 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2034 If defined, the number of milliseconds to delay between
2035 page writes. The default is zero milliseconds.
2037 - CFG_I2C_EEPROM_ADDR_LEN:
2038 The length in bytes of the EEPROM memory array address. Note
2039 that this is NOT the chip address length!
2041 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2042 EEPROM chips that implement "address overflow" are ones
2043 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2044 address and the extra bits end up in the "chip address" bit
2045 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2048 Note that we consider the length of the address field to
2049 still be one byte because the extra address bits are hidden
2050 in the chip address.
2053 The size in bytes of the EEPROM device.
2056 - CFG_ENV_IS_IN_DATAFLASH:
2058 Define this if you have a DataFlash memory device which you
2059 want to use for the environment.
2065 These three #defines specify the offset and size of the
2066 environment area within the total memory of your DataFlash placed
2067 at the specified address.
2069 - CFG_ENV_IS_IN_NAND:
2071 Define this if you have a NAND device which you want to use
2072 for the environment.
2077 These two #defines specify the offset and size of the environment
2078 area within the first NAND device.
2080 - CFG_ENV_OFFSET_REDUND
2082 This setting describes a second storage area of CFG_ENV_SIZE
2083 size used to hold a redundant copy of the environment data,
2084 so that there is a valid backup copy in case there is a
2085 power failure during a "saveenv" operation.
2087 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2088 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2089 the NAND devices block size.
2091 - CFG_SPI_INIT_OFFSET
2093 Defines offset to the initial SPI buffer area in DPRAM. The
2094 area is used at an early stage (ROM part) if the environment
2095 is configured to reside in the SPI EEPROM: We need a 520 byte
2096 scratch DPRAM area. It is used between the two initialization
2097 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2098 to be a good choice since it makes it far enough from the
2099 start of the data area as well as from the stack pointer.
2101 Please note that the environment is read-only as long as the monitor
2102 has been relocated to RAM and a RAM copy of the environment has been
2103 created; also, when using EEPROM you will have to use getenv_r()
2104 until then to read environment variables.
2106 The environment is protected by a CRC32 checksum. Before the monitor
2107 is relocated into RAM, as a result of a bad CRC you will be working
2108 with the compiled-in default environment - *silently*!!! [This is
2109 necessary, because the first environment variable we need is the
2110 "baudrate" setting for the console - if we have a bad CRC, we don't
2111 have any device yet where we could complain.]
2113 Note: once the monitor has been relocated, then it will complain if
2114 the default environment is used; a new CRC is computed as soon as you
2115 use the "saveenv" command to store a valid environment.
2117 - CFG_FAULT_ECHO_LINK_DOWN:
2118 Echo the inverted Ethernet link state to the fault LED.
2120 Note: If this option is active, then CFG_FAULT_MII_ADDR
2121 also needs to be defined.
2123 - CFG_FAULT_MII_ADDR:
2124 MII address of the PHY to check for the Ethernet link state.
2126 - CFG_64BIT_VSPRINTF:
2127 Makes vsprintf (and all *printf functions) support printing
2128 of 64bit values by using the L quantifier
2130 - CFG_64BIT_STRTOUL:
2131 Adds simple_strtoull that returns a 64bit value
2133 Low Level (hardware related) configuration options:
2134 ---------------------------------------------------
2136 - CFG_CACHELINE_SIZE:
2137 Cache Line Size of the CPU.
2140 Default address of the IMMR after system reset.
2142 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2143 and RPXsuper) to be able to adjust the position of
2144 the IMMR register after a reset.
2146 - Floppy Disk Support:
2147 CFG_FDC_DRIVE_NUMBER
2149 the default drive number (default value 0)
2153 defines the spacing between fdc chipset registers
2158 defines the offset of register from address. It
2159 depends on which part of the data bus is connected to
2160 the fdc chipset. (default value 0)
2162 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2163 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2166 if CFG_FDC_HW_INIT is defined, then the function
2167 fdc_hw_init() is called at the beginning of the FDC
2168 setup. fdc_hw_init() must be provided by the board
2169 source code. It is used to make hardware dependant
2172 - CFG_IMMR: Physical address of the Internal Memory.
2173 DO NOT CHANGE unless you know exactly what you're
2174 doing! (11-4) [MPC8xx/82xx systems only]
2176 - CFG_INIT_RAM_ADDR:
2178 Start address of memory area that can be used for
2179 initial data and stack; please note that this must be
2180 writable memory that is working WITHOUT special
2181 initialization, i. e. you CANNOT use normal RAM which
2182 will become available only after programming the
2183 memory controller and running certain initialization
2186 U-Boot uses the following memory types:
2187 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2188 - MPC824X: data cache
2189 - PPC4xx: data cache
2191 - CFG_GBL_DATA_OFFSET:
2193 Offset of the initial data structure in the memory
2194 area defined by CFG_INIT_RAM_ADDR. Usually
2195 CFG_GBL_DATA_OFFSET is chosen such that the initial
2196 data is located at the end of the available space
2197 (sometimes written as (CFG_INIT_RAM_END -
2198 CFG_INIT_DATA_SIZE), and the initial stack is just
2199 below that area (growing from (CFG_INIT_RAM_ADDR +
2200 CFG_GBL_DATA_OFFSET) downward.
2203 On the MPC824X (or other systems that use the data
2204 cache for initial memory) the address chosen for
2205 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2206 point to an otherwise UNUSED address space between
2207 the top of RAM and the start of the PCI space.
2209 - CFG_SIUMCR: SIU Module Configuration (11-6)
2211 - CFG_SYPCR: System Protection Control (11-9)
2213 - CFG_TBSCR: Time Base Status and Control (11-26)
2215 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2217 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2219 - CFG_SCCR: System Clock and reset Control Register (15-27)
2221 - CFG_OR_TIMING_SDRAM:
2225 periodic timer for refresh
2227 - CFG_DER: Debug Event Register (37-47)
2229 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2230 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2231 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2233 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2235 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2236 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2237 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2238 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2240 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2241 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2242 Machine Mode Register and Memory Periodic Timer
2243 Prescaler definitions (SDRAM timing)
2245 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2246 enable I2C microcode relocation patch (MPC8xx);
2247 define relocation offset in DPRAM [DSP2]
2249 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2250 enable SPI microcode relocation patch (MPC8xx);
2251 define relocation offset in DPRAM [SCC4]
2254 Use OSCM clock mode on MBX8xx board. Be careful,
2255 wrong setting might damage your board. Read
2256 doc/README.MBX before setting this variable!
2258 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2259 Offset of the bootmode word in DPRAM used by post
2260 (Power On Self Tests). This definition overrides
2261 #define'd default value in commproc.h resp.
2264 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2265 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2266 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2267 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2268 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2269 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2270 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2271 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2272 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2275 Get DDR timing information from an I2C EEPROM. Common with pluggable
2276 memory modules such as SODIMMs
2278 I2C address of the SPD EEPROM
2281 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2282 Note that the value must resolve to something your driver can deal with.
2284 - CFG_83XX_DDR_USES_CS0
2285 Only for 83xx systems. If specified, then DDR should be configured
2286 using CS0 and CS1 instead of CS2 and CS3.
2288 - CFG_83XX_DDR_USES_CS0
2289 Only for 83xx systems. If specified, then DDR should be configured
2290 using CS0 and CS1 instead of CS2 and CS3.
2292 - CONFIG_ETHER_ON_FEC[12]
2293 Define to enable FEC[12] on a 8xx series processor.
2295 - CONFIG_FEC[12]_PHY
2296 Define to the hardcoded PHY address which corresponds
2297 to the given FEC; i. e.
2298 #define CONFIG_FEC1_PHY 4
2299 means that the PHY with address 4 is connected to FEC1
2301 When set to -1, means to probe for first available.
2303 - CONFIG_FEC[12]_PHY_NORXERR
2304 The PHY does not have a RXERR line (RMII only).
2305 (so program the FEC to ignore it).
2308 Enable RMII mode for all FECs.
2309 Note that this is a global option, we can't
2310 have one FEC in standard MII mode and another in RMII mode.
2312 - CONFIG_CRC32_VERIFY
2313 Add a verify option to the crc32 command.
2316 => crc32 -v <address> <count> <crc32>
2318 Where address/count indicate a memory area
2319 and crc32 is the correct crc32 which the
2323 Add the "loopw" memory command. This only takes effect if
2324 the memory commands are activated globally (CONFIG_CMD_MEM).
2327 Add the "mdc" and "mwc" memory commands. These are cyclic
2332 This command will print 4 bytes (10,11,12,13) each 500 ms.
2334 => mwc.l 100 12345678 10
2335 This command will write 12345678 to address 100 all 10 ms.
2337 This only takes effect if the memory commands are activated
2338 globally (CONFIG_CMD_MEM).
2340 - CONFIG_SKIP_LOWLEVEL_INIT
2341 - CONFIG_SKIP_RELOCATE_UBOOT
2343 [ARM only] If these variables are defined, then
2344 certain low level initializations (like setting up
2345 the memory controller) are omitted and/or U-Boot does
2346 not relocate itself into RAM.
2347 Normally these variables MUST NOT be defined. The
2348 only exception is when U-Boot is loaded (to RAM) by
2349 some other boot loader or by a debugger which
2350 performs these intializations itself.
2353 Building the Software:
2354 ======================
2356 Building U-Boot has been tested in native PPC environments (on a
2357 PowerBook G3 running LinuxPPC 2000) and in cross environments
2358 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2361 If you are not using a native PPC environment, it is assumed that you
2362 have the GNU cross compiling tools available in your path and named
2363 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2364 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2365 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2368 CROSS_COMPILE = ppc_4xx-
2371 U-Boot is intended to be simple to build. After installing the
2372 sources you must configure U-Boot for one specific board type. This
2377 where "NAME_config" is the name of one of the existing
2378 configurations; the following names are supported:
2380 ADCIOP_config FPS860L_config omap730p2_config
2381 ADS860_config GEN860T_config pcu_e_config
2383 AR405_config GENIETV_config PIP405_config
2384 at91rm9200dk_config GTH_config QS823_config
2385 CANBT_config hermes_config QS850_config
2386 cmi_mpc5xx_config hymod_config QS860T_config
2387 cogent_common_config IP860_config RPXlite_config
2388 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2389 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2390 CPCI405_config JSE_config rsdproto_config
2391 CPCIISER4_config LANTEC_config Sandpoint8240_config
2392 csb272_config lwmon_config sbc8260_config
2393 CU824_config MBX860T_config sbc8560_33_config
2394 DUET_ADS_config MBX_config sbc8560_66_config
2395 EBONY_config mpc7448hpc2_config SM850_config
2396 ELPT860_config MPC8260ADS_config SPD823TS_config
2397 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2398 ETX094_config MPC8540EVAL_config SXNI855T_config
2399 FADS823_config NMPC8560ADS_config TQM823L_config
2400 FADS850SAR_config NETVIA_config TQM850L_config
2401 FADS860T_config omap1510inn_config TQM855L_config
2402 FPS850L_config omap1610h2_config TQM860L_config
2403 omap1610inn_config walnut_config
2404 omap5912osk_config Yukon8220_config
2405 omap2420h4_config ZPC1900_config
2407 Note: for some board special configuration names may exist; check if
2408 additional information is available from the board vendor; for
2409 instance, the TQM823L systems are available without (standard)
2410 or with LCD support. You can select such additional "features"
2411 when chosing the configuration, i. e.
2414 - will configure for a plain TQM823L, i. e. no LCD support
2416 make TQM823L_LCD_config
2417 - will configure for a TQM823L with U-Boot console on LCD
2422 Finally, type "make all", and you should get some working U-Boot
2423 images ready for download to / installation on your system:
2425 - "u-boot.bin" is a raw binary image
2426 - "u-boot" is an image in ELF binary format
2427 - "u-boot.srec" is in Motorola S-Record format
2429 By default the build is performed locally and the objects are saved
2430 in the source directory. One of the two methods can be used to change
2431 this behavior and build U-Boot to some external directory:
2433 1. Add O= to the make command line invocations:
2435 make O=/tmp/build distclean
2436 make O=/tmp/build NAME_config
2437 make O=/tmp/build all
2439 2. Set environment variable BUILD_DIR to point to the desired location:
2441 export BUILD_DIR=/tmp/build
2446 Note that the command line "O=" setting overrides the BUILD_DIR environment
2450 Please be aware that the Makefiles assume you are using GNU make, so
2451 for instance on NetBSD you might need to use "gmake" instead of
2455 If the system board that you have is not listed, then you will need
2456 to port U-Boot to your hardware platform. To do this, follow these
2459 1. Add a new configuration option for your board to the toplevel
2460 "Makefile" and to the "MAKEALL" script, using the existing
2461 entries as examples. Note that here and at many other places
2462 boards and other names are listed in alphabetical sort order. Please
2464 2. Create a new directory to hold your board specific code. Add any
2465 files you need. In your board directory, you will need at least
2466 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2467 3. Create a new configuration file "include/configs/<board>.h" for
2469 3. If you're porting U-Boot to a new CPU, then also create a new
2470 directory to hold your CPU specific code. Add any files you need.
2471 4. Run "make <board>_config" with your new name.
2472 5. Type "make", and you should get a working "u-boot.srec" file
2473 to be installed on your target system.
2474 6. Debug and solve any problems that might arise.
2475 [Of course, this last step is much harder than it sounds.]
2478 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2479 ==============================================================
2481 If you have modified U-Boot sources (for instance added a new board
2482 or support for new devices, a new CPU, etc.) you are expected to
2483 provide feedback to the other developers. The feedback normally takes
2484 the form of a "patch", i. e. a context diff against a certain (latest
2485 official or latest in CVS) version of U-Boot sources.
2487 But before you submit such a patch, please verify that your modifi-
2488 cation did not break existing code. At least make sure that *ALL* of
2489 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2490 just run the "MAKEALL" script, which will configure and build U-Boot
2491 for ALL supported system. Be warned, this will take a while. You can
2492 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2493 environment variable to the script, i. e. to use the cross tools from
2494 MontaVista's Hard Hat Linux you can type
2496 CROSS_COMPILE=ppc_8xx- MAKEALL
2498 or to build on a native PowerPC system you can type
2500 CROSS_COMPILE=' ' MAKEALL
2502 When using the MAKEALL script, the default behaviour is to build U-Boot
2503 in the source directory. This location can be changed by setting the
2504 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2505 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2506 <source dir>/LOG directory. This default location can be changed by
2507 setting the MAKEALL_LOGDIR environment variable. For example:
2509 export BUILD_DIR=/tmp/build
2510 export MAKEALL_LOGDIR=/tmp/log
2511 CROSS_COMPILE=ppc_8xx- MAKEALL
2513 With the above settings build objects are saved in the /tmp/build, log
2514 files are saved in the /tmp/log and the source tree remains clean during
2515 the whole build process.
2518 See also "U-Boot Porting Guide" below.
2521 Monitor Commands - Overview:
2522 ============================
2524 go - start application at address 'addr'
2525 run - run commands in an environment variable
2526 bootm - boot application image from memory
2527 bootp - boot image via network using BootP/TFTP protocol
2528 tftpboot- boot image via network using TFTP protocol
2529 and env variables "ipaddr" and "serverip"
2530 (and eventually "gatewayip")
2531 rarpboot- boot image via network using RARP/TFTP protocol
2532 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2533 loads - load S-Record file over serial line
2534 loadb - load binary file over serial line (kermit mode)
2536 mm - memory modify (auto-incrementing)
2537 nm - memory modify (constant address)
2538 mw - memory write (fill)
2540 cmp - memory compare
2541 crc32 - checksum calculation
2542 imd - i2c memory display
2543 imm - i2c memory modify (auto-incrementing)
2544 inm - i2c memory modify (constant address)
2545 imw - i2c memory write (fill)
2546 icrc32 - i2c checksum calculation
2547 iprobe - probe to discover valid I2C chip addresses
2548 iloop - infinite loop on address range
2549 isdram - print SDRAM configuration information
2550 sspi - SPI utility commands
2551 base - print or set address offset
2552 printenv- print environment variables
2553 setenv - set environment variables
2554 saveenv - save environment variables to persistent storage
2555 protect - enable or disable FLASH write protection
2556 erase - erase FLASH memory
2557 flinfo - print FLASH memory information
2558 bdinfo - print Board Info structure
2559 iminfo - print header information for application image
2560 coninfo - print console devices and informations
2561 ide - IDE sub-system
2562 loop - infinite loop on address range
2563 loopw - infinite write loop on address range
2564 mtest - simple RAM test
2565 icache - enable or disable instruction cache
2566 dcache - enable or disable data cache
2567 reset - Perform RESET of the CPU
2568 echo - echo args to console
2569 version - print monitor version
2570 help - print online help
2571 ? - alias for 'help'
2574 Monitor Commands - Detailed Description:
2575 ========================================
2579 For now: just type "help <command>".
2582 Environment Variables:
2583 ======================
2585 U-Boot supports user configuration using Environment Variables which
2586 can be made persistent by saving to Flash memory.
2588 Environment Variables are set using "setenv", printed using
2589 "printenv", and saved to Flash using "saveenv". Using "setenv"
2590 without a value can be used to delete a variable from the
2591 environment. As long as you don't save the environment you are
2592 working with an in-memory copy. In case the Flash area containing the
2593 environment is erased by accident, a default environment is provided.
2595 Some configuration options can be set using Environment Variables:
2597 baudrate - see CONFIG_BAUDRATE
2599 bootdelay - see CONFIG_BOOTDELAY
2601 bootcmd - see CONFIG_BOOTCOMMAND
2603 bootargs - Boot arguments when booting an RTOS image
2605 bootfile - Name of the image to load with TFTP
2607 autoload - if set to "no" (any string beginning with 'n'),
2608 "bootp" will just load perform a lookup of the
2609 configuration from the BOOTP server, but not try to
2610 load any image using TFTP
2612 autostart - if set to "yes", an image loaded using the "bootp",
2613 "rarpboot", "tftpboot" or "diskboot" commands will
2614 be automatically started (by internally calling
2617 If set to "no", a standalone image passed to the
2618 "bootm" command will be copied to the load address
2619 (and eventually uncompressed), but NOT be started.
2620 This can be used to load and uncompress arbitrary
2623 i2cfast - (PPC405GP|PPC405EP only)
2624 if set to 'y' configures Linux I2C driver for fast
2625 mode (400kHZ). This environment variable is used in
2626 initialization code. So, for changes to be effective
2627 it must be saved and board must be reset.
2629 initrd_high - restrict positioning of initrd images:
2630 If this variable is not set, initrd images will be
2631 copied to the highest possible address in RAM; this
2632 is usually what you want since it allows for
2633 maximum initrd size. If for some reason you want to
2634 make sure that the initrd image is loaded below the
2635 CFG_BOOTMAPSZ limit, you can set this environment
2636 variable to a value of "no" or "off" or "0".
2637 Alternatively, you can set it to a maximum upper
2638 address to use (U-Boot will still check that it
2639 does not overwrite the U-Boot stack and data).
2641 For instance, when you have a system with 16 MB
2642 RAM, and want to reserve 4 MB from use by Linux,
2643 you can do this by adding "mem=12M" to the value of
2644 the "bootargs" variable. However, now you must make
2645 sure that the initrd image is placed in the first
2646 12 MB as well - this can be done with
2648 setenv initrd_high 00c00000
2650 If you set initrd_high to 0xFFFFFFFF, this is an
2651 indication to U-Boot that all addresses are legal
2652 for the Linux kernel, including addresses in flash
2653 memory. In this case U-Boot will NOT COPY the
2654 ramdisk at all. This may be useful to reduce the
2655 boot time on your system, but requires that this
2656 feature is supported by your Linux kernel.
2658 ipaddr - IP address; needed for tftpboot command
2660 loadaddr - Default load address for commands like "bootp",
2661 "rarpboot", "tftpboot", "loadb" or "diskboot"
2663 loads_echo - see CONFIG_LOADS_ECHO
2665 serverip - TFTP server IP address; needed for tftpboot command
2667 bootretry - see CONFIG_BOOT_RETRY_TIME
2669 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2671 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2673 ethprime - When CONFIG_NET_MULTI is enabled controls which
2674 interface is used first.
2676 ethact - When CONFIG_NET_MULTI is enabled controls which
2677 interface is currently active. For example you
2678 can do the following
2680 => setenv ethact FEC ETHERNET
2681 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2682 => setenv ethact SCC ETHERNET
2683 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2685 netretry - When set to "no" each network operation will
2686 either succeed or fail without retrying.
2687 When set to "once" the network operation will
2688 fail when all the available network interfaces
2689 are tried once without success.
2690 Useful on scripts which control the retry operation
2693 tftpsrcport - If this is set, the value is used for TFTP's
2696 tftpdstport - If this is set, the value is used for TFTP's UDP
2697 destination port instead of the Well Know Port 69.
2699 vlan - When set to a value < 4095 the traffic over
2700 ethernet is encapsulated/received over 802.1q
2703 The following environment variables may be used and automatically
2704 updated by the network boot commands ("bootp" and "rarpboot"),
2705 depending the information provided by your boot server:
2707 bootfile - see above
2708 dnsip - IP address of your Domain Name Server
2709 dnsip2 - IP address of your secondary Domain Name Server
2710 gatewayip - IP address of the Gateway (Router) to use
2711 hostname - Target hostname
2713 netmask - Subnet Mask
2714 rootpath - Pathname of the root filesystem on the NFS server
2715 serverip - see above
2718 There are two special Environment Variables:
2720 serial# - contains hardware identification information such
2721 as type string and/or serial number
2722 ethaddr - Ethernet address
2724 These variables can be set only once (usually during manufacturing of
2725 the board). U-Boot refuses to delete or overwrite these variables
2726 once they have been set once.
2729 Further special Environment Variables:
2731 ver - Contains the U-Boot version string as printed
2732 with the "version" command. This variable is
2733 readonly (see CONFIG_VERSION_VARIABLE).
2736 Please note that changes to some configuration parameters may take
2737 only effect after the next boot (yes, that's just like Windoze :-).
2740 Command Line Parsing:
2741 =====================
2743 There are two different command line parsers available with U-Boot:
2744 the old "simple" one, and the much more powerful "hush" shell:
2746 Old, simple command line parser:
2747 --------------------------------
2749 - supports environment variables (through setenv / saveenv commands)
2750 - several commands on one line, separated by ';'
2751 - variable substitution using "... ${name} ..." syntax
2752 - special characters ('$', ';') can be escaped by prefixing with '\',
2754 setenv bootcmd bootm \${address}
2755 - You can also escape text by enclosing in single apostrophes, for example:
2756 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2761 - similar to Bourne shell, with control structures like
2762 if...then...else...fi, for...do...done; while...do...done,
2763 until...do...done, ...
2764 - supports environment ("global") variables (through setenv / saveenv
2765 commands) and local shell variables (through standard shell syntax
2766 "name=value"); only environment variables can be used with "run"
2772 (1) If a command line (or an environment variable executed by a "run"
2773 command) contains several commands separated by semicolon, and
2774 one of these commands fails, then the remaining commands will be
2777 (2) If you execute several variables with one call to run (i. e.
2778 calling run with a list af variables as arguments), any failing
2779 command will cause "run" to terminate, i. e. the remaining
2780 variables are not executed.
2782 Note for Redundant Ethernet Interfaces:
2783 =======================================
2785 Some boards come with redundant ethernet interfaces; U-Boot supports
2786 such configurations and is capable of automatic selection of a
2787 "working" interface when needed. MAC assignment works as follows:
2789 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2790 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2791 "eth1addr" (=>eth1), "eth2addr", ...
2793 If the network interface stores some valid MAC address (for instance
2794 in SROM), this is used as default address if there is NO correspon-
2795 ding setting in the environment; if the corresponding environment
2796 variable is set, this overrides the settings in the card; that means:
2798 o If the SROM has a valid MAC address, and there is no address in the
2799 environment, the SROM's address is used.
2801 o If there is no valid address in the SROM, and a definition in the
2802 environment exists, then the value from the environment variable is
2805 o If both the SROM and the environment contain a MAC address, and
2806 both addresses are the same, this MAC address is used.
2808 o If both the SROM and the environment contain a MAC address, and the
2809 addresses differ, the value from the environment is used and a
2812 o If neither SROM nor the environment contain a MAC address, an error
2819 The "boot" commands of this monitor operate on "image" files which
2820 can be basicly anything, preceeded by a special header; see the
2821 definitions in include/image.h for details; basicly, the header
2822 defines the following image properties:
2824 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2825 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2826 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2827 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2828 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2829 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2830 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2831 * Compression Type (uncompressed, gzip, bzip2)
2837 The header is marked by a special Magic Number, and both the header
2838 and the data portions of the image are secured against corruption by
2845 Although U-Boot should support any OS or standalone application
2846 easily, the main focus has always been on Linux during the design of
2849 U-Boot includes many features that so far have been part of some
2850 special "boot loader" code within the Linux kernel. Also, any
2851 "initrd" images to be used are no longer part of one big Linux image;
2852 instead, kernel and "initrd" are separate images. This implementation
2853 serves several purposes:
2855 - the same features can be used for other OS or standalone
2856 applications (for instance: using compressed images to reduce the
2857 Flash memory footprint)
2859 - it becomes much easier to port new Linux kernel versions because
2860 lots of low-level, hardware dependent stuff are done by U-Boot
2862 - the same Linux kernel image can now be used with different "initrd"
2863 images; of course this also means that different kernel images can
2864 be run with the same "initrd". This makes testing easier (you don't
2865 have to build a new "zImage.initrd" Linux image when you just
2866 change a file in your "initrd"). Also, a field-upgrade of the
2867 software is easier now.
2873 Porting Linux to U-Boot based systems:
2874 ---------------------------------------
2876 U-Boot cannot save you from doing all the necessary modifications to
2877 configure the Linux device drivers for use with your target hardware
2878 (no, we don't intend to provide a full virtual machine interface to
2881 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2883 Just make sure your machine specific header file (for instance
2884 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2885 Information structure as we define in include/u-boot.h, and make
2886 sure that your definition of IMAP_ADDR uses the same value as your
2887 U-Boot configuration in CFG_IMMR.
2890 Configuring the Linux kernel:
2891 -----------------------------
2893 No specific requirements for U-Boot. Make sure you have some root
2894 device (initial ramdisk, NFS) for your target system.
2897 Building a Linux Image:
2898 -----------------------
2900 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2901 not used. If you use recent kernel source, a new build target
2902 "uImage" will exist which automatically builds an image usable by
2903 U-Boot. Most older kernels also have support for a "pImage" target,
2904 which was introduced for our predecessor project PPCBoot and uses a
2905 100% compatible format.
2914 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2915 encapsulate a compressed Linux kernel image with header information,
2916 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2918 * build a standard "vmlinux" kernel image (in ELF binary format):
2920 * convert the kernel into a raw binary image:
2922 ${CROSS_COMPILE}-objcopy -O binary \
2923 -R .note -R .comment \
2924 -S vmlinux linux.bin
2926 * compress the binary image:
2930 * package compressed binary image for U-Boot:
2932 mkimage -A ppc -O linux -T kernel -C gzip \
2933 -a 0 -e 0 -n "Linux Kernel Image" \
2934 -d linux.bin.gz uImage
2937 The "mkimage" tool can also be used to create ramdisk images for use
2938 with U-Boot, either separated from the Linux kernel image, or
2939 combined into one file. "mkimage" encapsulates the images with a 64
2940 byte header containing information about target architecture,
2941 operating system, image type, compression method, entry points, time
2942 stamp, CRC32 checksums, etc.
2944 "mkimage" can be called in two ways: to verify existing images and
2945 print the header information, or to build new images.
2947 In the first form (with "-l" option) mkimage lists the information
2948 contained in the header of an existing U-Boot image; this includes
2949 checksum verification:
2951 tools/mkimage -l image
2952 -l ==> list image header information
2954 The second form (with "-d" option) is used to build a U-Boot image
2955 from a "data file" which is used as image payload:
2957 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2958 -n name -d data_file image
2959 -A ==> set architecture to 'arch'
2960 -O ==> set operating system to 'os'
2961 -T ==> set image type to 'type'
2962 -C ==> set compression type 'comp'
2963 -a ==> set load address to 'addr' (hex)
2964 -e ==> set entry point to 'ep' (hex)
2965 -n ==> set image name to 'name'
2966 -d ==> use image data from 'datafile'
2968 Right now, all Linux kernels for PowerPC systems use the same load
2969 address (0x00000000), but the entry point address depends on the
2972 - 2.2.x kernels have the entry point at 0x0000000C,
2973 - 2.3.x and later kernels have the entry point at 0x00000000.
2975 So a typical call to build a U-Boot image would read:
2977 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2978 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2979 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2980 > examples/uImage.TQM850L
2981 Image Name: 2.4.4 kernel for TQM850L
2982 Created: Wed Jul 19 02:34:59 2000
2983 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2984 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2985 Load Address: 0x00000000
2986 Entry Point: 0x00000000
2988 To verify the contents of the image (or check for corruption):
2990 -> tools/mkimage -l examples/uImage.TQM850L
2991 Image Name: 2.4.4 kernel for TQM850L
2992 Created: Wed Jul 19 02:34:59 2000
2993 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2994 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2995 Load Address: 0x00000000
2996 Entry Point: 0x00000000
2998 NOTE: for embedded systems where boot time is critical you can trade
2999 speed for memory and install an UNCOMPRESSED image instead: this
3000 needs more space in Flash, but boots much faster since it does not
3001 need to be uncompressed:
3003 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3004 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3005 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3006 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3007 > examples/uImage.TQM850L-uncompressed
3008 Image Name: 2.4.4 kernel for TQM850L
3009 Created: Wed Jul 19 02:34:59 2000
3010 Image Type: PowerPC Linux Kernel Image (uncompressed)
3011 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3012 Load Address: 0x00000000
3013 Entry Point: 0x00000000
3016 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3017 when your kernel is intended to use an initial ramdisk:
3019 -> tools/mkimage -n 'Simple Ramdisk Image' \
3020 > -A ppc -O linux -T ramdisk -C gzip \
3021 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3022 Image Name: Simple Ramdisk Image
3023 Created: Wed Jan 12 14:01:50 2000
3024 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3025 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3026 Load Address: 0x00000000
3027 Entry Point: 0x00000000
3030 Installing a Linux Image:
3031 -------------------------
3033 To downloading a U-Boot image over the serial (console) interface,
3034 you must convert the image to S-Record format:
3036 objcopy -I binary -O srec examples/image examples/image.srec
3038 The 'objcopy' does not understand the information in the U-Boot
3039 image header, so the resulting S-Record file will be relative to
3040 address 0x00000000. To load it to a given address, you need to
3041 specify the target address as 'offset' parameter with the 'loads'
3044 Example: install the image to address 0x40100000 (which on the
3045 TQM8xxL is in the first Flash bank):
3047 => erase 40100000 401FFFFF
3053 ## Ready for S-Record download ...
3054 ~>examples/image.srec
3055 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3057 15989 15990 15991 15992
3058 [file transfer complete]
3060 ## Start Addr = 0x00000000
3063 You can check the success of the download using the 'iminfo' command;
3064 this includes a checksum verification so you can be sure no data
3065 corruption happened:
3069 ## Checking Image at 40100000 ...
3070 Image Name: 2.2.13 for initrd on TQM850L
3071 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3072 Data Size: 335725 Bytes = 327 kB = 0 MB
3073 Load Address: 00000000
3074 Entry Point: 0000000c
3075 Verifying Checksum ... OK
3081 The "bootm" command is used to boot an application that is stored in
3082 memory (RAM or Flash). In case of a Linux kernel image, the contents
3083 of the "bootargs" environment variable is passed to the kernel as
3084 parameters. You can check and modify this variable using the
3085 "printenv" and "setenv" commands:
3088 => printenv bootargs
3089 bootargs=root=/dev/ram
3091 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3093 => printenv bootargs
3094 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3097 ## Booting Linux kernel at 40020000 ...
3098 Image Name: 2.2.13 for NFS on TQM850L
3099 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3100 Data Size: 381681 Bytes = 372 kB = 0 MB
3101 Load Address: 00000000
3102 Entry Point: 0000000c
3103 Verifying Checksum ... OK
3104 Uncompressing Kernel Image ... OK
3105 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
3106 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3107 time_init: decrementer frequency = 187500000/60
3108 Calibrating delay loop... 49.77 BogoMIPS
3109 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3112 If you want to boot a Linux kernel with initial ram disk, you pass
3113 the memory addresses of both the kernel and the initrd image (PPBCOOT
3114 format!) to the "bootm" command:
3116 => imi 40100000 40200000
3118 ## Checking Image at 40100000 ...
3119 Image Name: 2.2.13 for initrd on TQM850L
3120 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3121 Data Size: 335725 Bytes = 327 kB = 0 MB
3122 Load Address: 00000000
3123 Entry Point: 0000000c
3124 Verifying Checksum ... OK
3126 ## Checking Image at 40200000 ...
3127 Image Name: Simple Ramdisk Image
3128 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3129 Data Size: 566530 Bytes = 553 kB = 0 MB
3130 Load Address: 00000000
3131 Entry Point: 00000000
3132 Verifying Checksum ... OK
3134 => bootm 40100000 40200000
3135 ## Booting Linux kernel at 40100000 ...
3136 Image Name: 2.2.13 for initrd on TQM850L
3137 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3138 Data Size: 335725 Bytes = 327 kB = 0 MB
3139 Load Address: 00000000
3140 Entry Point: 0000000c
3141 Verifying Checksum ... OK
3142 Uncompressing Kernel Image ... OK
3143 ## Loading RAMDisk Image at 40200000 ...
3144 Image Name: Simple Ramdisk Image
3145 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3146 Data Size: 566530 Bytes = 553 kB = 0 MB
3147 Load Address: 00000000
3148 Entry Point: 00000000
3149 Verifying Checksum ... OK
3150 Loading Ramdisk ... OK
3151 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
3152 Boot arguments: root=/dev/ram
3153 time_init: decrementer frequency = 187500000/60
3154 Calibrating delay loop... 49.77 BogoMIPS
3156 RAMDISK: Compressed image found at block 0
3157 VFS: Mounted root (ext2 filesystem).
3161 Boot Linux and pass a flat device tree:
3164 First, U-Boot must be compiled with the appropriate defines. See the section
3165 titled "Linux Kernel Interface" above for a more in depth explanation. The
3166 following is an example of how to start a kernel and pass an updated
3172 oft=oftrees/mpc8540ads.dtb
3173 => tftp $oftaddr $oft
3174 Speed: 1000, full duplex
3176 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3177 Filename 'oftrees/mpc8540ads.dtb'.
3178 Load address: 0x300000
3181 Bytes transferred = 4106 (100a hex)
3182 => tftp $loadaddr $bootfile
3183 Speed: 1000, full duplex
3185 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3187 Load address: 0x200000
3188 Loading:############
3190 Bytes transferred = 1029407 (fb51f hex)
3195 => bootm $loadaddr - $oftaddr
3196 ## Booting image at 00200000 ...
3197 Image Name: Linux-2.6.17-dirty
3198 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3199 Data Size: 1029343 Bytes = 1005.2 kB
3200 Load Address: 00000000
3201 Entry Point: 00000000
3202 Verifying Checksum ... OK
3203 Uncompressing Kernel Image ... OK
3204 Booting using flat device tree at 0x300000
3205 Using MPC85xx ADS machine description
3206 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3210 More About U-Boot Image Types:
3211 ------------------------------
3213 U-Boot supports the following image types:
3215 "Standalone Programs" are directly runnable in the environment
3216 provided by U-Boot; it is expected that (if they behave
3217 well) you can continue to work in U-Boot after return from
3218 the Standalone Program.
3219 "OS Kernel Images" are usually images of some Embedded OS which
3220 will take over control completely. Usually these programs
3221 will install their own set of exception handlers, device
3222 drivers, set up the MMU, etc. - this means, that you cannot
3223 expect to re-enter U-Boot except by resetting the CPU.
3224 "RAMDisk Images" are more or less just data blocks, and their
3225 parameters (address, size) are passed to an OS kernel that is
3227 "Multi-File Images" contain several images, typically an OS
3228 (Linux) kernel image and one or more data images like
3229 RAMDisks. This construct is useful for instance when you want
3230 to boot over the network using BOOTP etc., where the boot
3231 server provides just a single image file, but you want to get
3232 for instance an OS kernel and a RAMDisk image.
3234 "Multi-File Images" start with a list of image sizes, each
3235 image size (in bytes) specified by an "uint32_t" in network
3236 byte order. This list is terminated by an "(uint32_t)0".
3237 Immediately after the terminating 0 follow the images, one by
3238 one, all aligned on "uint32_t" boundaries (size rounded up to
3239 a multiple of 4 bytes).
3241 "Firmware Images" are binary images containing firmware (like
3242 U-Boot or FPGA images) which usually will be programmed to
3245 "Script files" are command sequences that will be executed by
3246 U-Boot's command interpreter; this feature is especially
3247 useful when you configure U-Boot to use a real shell (hush)
3248 as command interpreter.
3254 One of the features of U-Boot is that you can dynamically load and
3255 run "standalone" applications, which can use some resources of
3256 U-Boot like console I/O functions or interrupt services.
3258 Two simple examples are included with the sources:
3263 'examples/hello_world.c' contains a small "Hello World" Demo
3264 application; it is automatically compiled when you build U-Boot.
3265 It's configured to run at address 0x00040004, so you can play with it
3269 ## Ready for S-Record download ...
3270 ~>examples/hello_world.srec
3271 1 2 3 4 5 6 7 8 9 10 11 ...
3272 [file transfer complete]
3274 ## Start Addr = 0x00040004
3276 => go 40004 Hello World! This is a test.
3277 ## Starting application at 0x00040004 ...
3288 Hit any key to exit ...
3290 ## Application terminated, rc = 0x0
3292 Another example, which demonstrates how to register a CPM interrupt
3293 handler with the U-Boot code, can be found in 'examples/timer.c'.
3294 Here, a CPM timer is set up to generate an interrupt every second.
3295 The interrupt service routine is trivial, just printing a '.'
3296 character, but this is just a demo program. The application can be
3297 controlled by the following keys:
3299 ? - print current values og the CPM Timer registers
3300 b - enable interrupts and start timer
3301 e - stop timer and disable interrupts
3302 q - quit application
3305 ## Ready for S-Record download ...
3306 ~>examples/timer.srec
3307 1 2 3 4 5 6 7 8 9 10 11 ...
3308 [file transfer complete]
3310 ## Start Addr = 0x00040004
3313 ## Starting application at 0x00040004 ...
3316 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3319 [q, b, e, ?] Set interval 1000000 us
3322 [q, b, e, ?] ........
3323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3326 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3334 [q, b, e, ?] ...Stopping timer
3336 [q, b, e, ?] ## Application terminated, rc = 0x0
3342 Over time, many people have reported problems when trying to use the
3343 "minicom" terminal emulation program for serial download. I (wd)
3344 consider minicom to be broken, and recommend not to use it. Under
3345 Unix, I recommend to use C-Kermit for general purpose use (and
3346 especially for kermit binary protocol download ("loadb" command), and
3347 use "cu" for S-Record download ("loads" command).
3349 Nevertheless, if you absolutely want to use it try adding this
3350 configuration to your "File transfer protocols" section:
3352 Name Program Name U/D FullScr IO-Red. Multi
3353 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3354 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3360 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3361 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3363 Building requires a cross environment; it is known to work on
3364 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3365 need gmake since the Makefiles are not compatible with BSD make).
3366 Note that the cross-powerpc package does not install include files;
3367 attempting to build U-Boot will fail because <machine/ansi.h> is
3368 missing. This file has to be installed and patched manually:
3370 # cd /usr/pkg/cross/powerpc-netbsd/include
3372 # ln -s powerpc machine
3373 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3374 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3376 Native builds *don't* work due to incompatibilities between native
3377 and U-Boot include files.
3379 Booting assumes that (the first part of) the image booted is a
3380 stage-2 loader which in turn loads and then invokes the kernel
3381 proper. Loader sources will eventually appear in the NetBSD source
3382 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3383 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3386 Implementation Internals:
3387 =========================
3389 The following is not intended to be a complete description of every
3390 implementation detail. However, it should help to understand the
3391 inner workings of U-Boot and make it easier to port it to custom
3395 Initial Stack, Global Data:
3396 ---------------------------
3398 The implementation of U-Boot is complicated by the fact that U-Boot
3399 starts running out of ROM (flash memory), usually without access to
3400 system RAM (because the memory controller is not initialized yet).
3401 This means that we don't have writable Data or BSS segments, and BSS
3402 is not initialized as zero. To be able to get a C environment working
3403 at all, we have to allocate at least a minimal stack. Implementation
3404 options for this are defined and restricted by the CPU used: Some CPU
3405 models provide on-chip memory (like the IMMR area on MPC8xx and
3406 MPC826x processors), on others (parts of) the data cache can be
3407 locked as (mis-) used as memory, etc.
3409 Chris Hallinan posted a good summary of these issues to the
3410 u-boot-users mailing list:
3412 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3413 From: "Chris Hallinan" <clh@net1plus.com>
3414 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3417 Correct me if I'm wrong, folks, but the way I understand it
3418 is this: Using DCACHE as initial RAM for Stack, etc, does not
3419 require any physical RAM backing up the cache. The cleverness
3420 is that the cache is being used as a temporary supply of
3421 necessary storage before the SDRAM controller is setup. It's
3422 beyond the scope of this list to expain the details, but you
3423 can see how this works by studying the cache architecture and
3424 operation in the architecture and processor-specific manuals.
3426 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3427 is another option for the system designer to use as an
3428 initial stack/ram area prior to SDRAM being available. Either
3429 option should work for you. Using CS 4 should be fine if your
3430 board designers haven't used it for something that would
3431 cause you grief during the initial boot! It is frequently not
3434 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3435 with your processor/board/system design. The default value
3436 you will find in any recent u-boot distribution in
3437 walnut.h should work for you. I'd set it to a value larger
3438 than your SDRAM module. If you have a 64MB SDRAM module, set
3439 it above 400_0000. Just make sure your board has no resources
3440 that are supposed to respond to that address! That code in
3441 start.S has been around a while and should work as is when
3442 you get the config right.
3447 It is essential to remember this, since it has some impact on the C
3448 code for the initialization procedures:
3450 * Initialized global data (data segment) is read-only. Do not attempt
3453 * Do not use any unitialized global data (or implicitely initialized
3454 as zero data - BSS segment) at all - this is undefined, initiali-
3455 zation is performed later (when relocating to RAM).
3457 * Stack space is very limited. Avoid big data buffers or things like
3460 Having only the stack as writable memory limits means we cannot use
3461 normal global data to share information beween the code. But it
3462 turned out that the implementation of U-Boot can be greatly
3463 simplified by making a global data structure (gd_t) available to all
3464 functions. We could pass a pointer to this data as argument to _all_
3465 functions, but this would bloat the code. Instead we use a feature of
3466 the GCC compiler (Global Register Variables) to share the data: we
3467 place a pointer (gd) to the global data into a register which we
3468 reserve for this purpose.
3470 When choosing a register for such a purpose we are restricted by the
3471 relevant (E)ABI specifications for the current architecture, and by
3472 GCC's implementation.
3474 For PowerPC, the following registers have specific use:
3477 R3-R4: parameter passing and return values
3478 R5-R10: parameter passing
3479 R13: small data area pointer
3483 (U-Boot also uses R14 as internal GOT pointer.)
3485 ==> U-Boot will use R29 to hold a pointer to the global data
3487 Note: on PPC, we could use a static initializer (since the
3488 address of the global data structure is known at compile time),
3489 but it turned out that reserving a register results in somewhat
3490 smaller code - although the code savings are not that big (on
3491 average for all boards 752 bytes for the whole U-Boot image,
3492 624 text + 127 data).
3494 On ARM, the following registers are used:
3496 R0: function argument word/integer result
3497 R1-R3: function argument word
3499 R10: stack limit (used only if stack checking if enabled)
3500 R11: argument (frame) pointer
3501 R12: temporary workspace
3504 R15: program counter
3506 ==> U-Boot will use R8 to hold a pointer to the global data
3508 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3509 or current versions of GCC may "optimize" the code too much.
3514 U-Boot runs in system state and uses physical addresses, i.e. the
3515 MMU is not used either for address mapping nor for memory protection.
3517 The available memory is mapped to fixed addresses using the memory
3518 controller. In this process, a contiguous block is formed for each
3519 memory type (Flash, SDRAM, SRAM), even when it consists of several
3520 physical memory banks.
3522 U-Boot is installed in the first 128 kB of the first Flash bank (on
3523 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3524 booting and sizing and initializing DRAM, the code relocates itself
3525 to the upper end of DRAM. Immediately below the U-Boot code some
3526 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3527 configuration setting]. Below that, a structure with global Board
3528 Info data is placed, followed by the stack (growing downward).
3530 Additionally, some exception handler code is copied to the low 8 kB
3531 of DRAM (0x00000000 ... 0x00001FFF).
3533 So a typical memory configuration with 16 MB of DRAM could look like
3536 0x0000 0000 Exception Vector code
3539 0x0000 2000 Free for Application Use
3545 0x00FB FF20 Monitor Stack (Growing downward)
3546 0x00FB FFAC Board Info Data and permanent copy of global data
3547 0x00FC 0000 Malloc Arena
3550 0x00FE 0000 RAM Copy of Monitor Code
3551 ... eventually: LCD or video framebuffer
3552 ... eventually: pRAM (Protected RAM - unchanged by reset)
3553 0x00FF FFFF [End of RAM]
3556 System Initialization:
3557 ----------------------
3559 In the reset configuration, U-Boot starts at the reset entry point
3560 (on most PowerPC systens at address 0x00000100). Because of the reset
3561 configuration for CS0# this is a mirror of the onboard Flash memory.
3562 To be able to re-map memory U-Boot then jumps to its link address.
3563 To be able to implement the initialization code in C, a (small!)
3564 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3565 which provide such a feature like MPC8xx or MPC8260), or in a locked
3566 part of the data cache. After that, U-Boot initializes the CPU core,
3567 the caches and the SIU.
3569 Next, all (potentially) available memory banks are mapped using a
3570 preliminary mapping. For example, we put them on 512 MB boundaries
3571 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3572 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3573 programmed for SDRAM access. Using the temporary configuration, a
3574 simple memory test is run that determines the size of the SDRAM
3577 When there is more than one SDRAM bank, and the banks are of
3578 different size, the largest is mapped first. For equal size, the first
3579 bank (CS2#) is mapped first. The first mapping is always for address
3580 0x00000000, with any additional banks following immediately to create
3581 contiguous memory starting from 0.
3583 Then, the monitor installs itself at the upper end of the SDRAM area
3584 and allocates memory for use by malloc() and for the global Board
3585 Info data; also, the exception vector code is copied to the low RAM
3586 pages, and the final stack is set up.
3588 Only after this relocation will you have a "normal" C environment;
3589 until that you are restricted in several ways, mostly because you are
3590 running from ROM, and because the code will have to be relocated to a
3594 U-Boot Porting Guide:
3595 ----------------------
3597 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3601 int main (int argc, char *argv[])
3603 sighandler_t no_more_time;
3605 signal (SIGALRM, no_more_time);
3606 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3608 if (available_money > available_manpower) {
3609 pay consultant to port U-Boot;
3613 Download latest U-Boot source;
3615 Subscribe to u-boot-users mailing list;
3618 email ("Hi, I am new to U-Boot, how do I get started?");
3622 Read the README file in the top level directory;
3623 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3624 Read the source, Luke;
3627 if (available_money > toLocalCurrency ($2500)) {
3630 Add a lot of aggravation and time;
3633 Create your own board support subdirectory;
3635 Create your own board config file;
3639 Add / modify source code;
3643 email ("Hi, I am having problems...");
3645 Send patch file to Wolfgang;
3650 void no_more_time (int sig)
3659 All contributions to U-Boot should conform to the Linux kernel
3660 coding style; see the file "Documentation/CodingStyle" and the script
3661 "scripts/Lindent" in your Linux kernel source directory. In sources
3662 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3663 spaces before parameters to function calls) is actually used.
3665 Source files originating from a different project (for example the
3666 MTD subsystem) are generally exempt from these guidelines and are not
3667 reformated to ease subsequent migration to newer versions of those
3670 Please note that U-Boot is implemented in C (and to some small parts in
3671 Assembler); no C++ is used, so please do not use C++ style comments (//)
3674 Please also stick to the following formatting rules:
3675 - remove any trailing white space
3676 - use TAB characters for indentation, not spaces
3677 - make sure NOT to use DOS '\r\n' line feeds
3678 - do not add more than 2 empty lines to source files
3679 - do not add trailing empty lines to source files
3681 Submissions which do not conform to the standards may be returned
3682 with a request to reformat the changes.
3688 Since the number of patches for U-Boot is growing, we need to
3689 establish some rules. Submissions which do not conform to these rules
3690 may be rejected, even when they contain important and valuable stuff.
3692 Patches shall be sent to the u-boot-users mailing list.
3694 When you send a patch, please include the following information with
3697 * For bug fixes: a description of the bug and how your patch fixes
3698 this bug. Please try to include a way of demonstrating that the
3699 patch actually fixes something.
3701 * For new features: a description of the feature and your
3704 * A CHANGELOG entry as plaintext (separate from the patch)
3706 * For major contributions, your entry to the CREDITS file
3708 * When you add support for a new board, don't forget to add this
3709 board to the MAKEALL script, too.
3711 * If your patch adds new configuration options, don't forget to
3712 document these in the README file.
3714 * The patch itself. If you are accessing the CVS repository use "cvs
3715 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3716 version of diff does not support these options, then get the latest
3717 version of GNU diff.
3719 The current directory when running this command shall be the top
3720 level directory of the U-Boot source tree, or it's parent directory
3721 (i. e. please make sure that your patch includes sufficient
3722 directory information for the affected files).
3724 We accept patches as plain text, MIME attachments or as uuencoded
3727 * If one logical set of modifications affects or creates several
3728 files, all these changes shall be submitted in a SINGLE patch file.
3730 * Changesets that contain different, unrelated modifications shall be
3731 submitted as SEPARATE patches, one patch per changeset.
3736 * Before sending the patch, run the MAKEALL script on your patched
3737 source tree and make sure that no errors or warnings are reported
3738 for any of the boards.
3740 * Keep your modifications to the necessary minimum: A patch
3741 containing several unrelated changes or arbitrary reformats will be
3742 returned with a request to re-formatting / split it.
3744 * If you modify existing code, make sure that your new code does not
3745 add to the memory footprint of the code ;-) Small is beautiful!
3746 When adding new features, these should compile conditionally only
3747 (using #ifdef), and the resulting code with the new feature
3748 disabled must not need more memory than the old code without your
3751 * Remember that there is a size limit of 40 kB per message on the
3752 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob