2 # (C) Copyright 2000 - 2008
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. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot-users@lists.sourceforge.net>. There is also an archive of
64 previous traffic on the mailing list - please search the archive
65 before asking FAQ's. Please see
66 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Ofifcial releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/UBoot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - i386 Files specific to i386 CPUs
155 - ixp Files specific to Intel XScale IXP CPUs
156 - leon2 Files specific to Gaisler LEON2 SPARC CPU
157 - leon3 Files specific to Gaisler LEON3 SPARC CPU
158 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
159 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
160 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
161 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
162 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
163 - mips Files specific to MIPS CPUs
164 - mpc5xx Files specific to Freescale MPC5xx CPUs
165 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
166 - mpc8xx Files specific to Freescale MPC8xx CPUs
167 - mpc8220 Files specific to Freescale MPC8220 CPUs
168 - mpc824x Files specific to Freescale MPC824x CPUs
169 - mpc8260 Files specific to Freescale MPC8260 CPUs
170 - mpc85xx Files specific to Freescale MPC85xx CPUs
171 - nios Files specific to Altera NIOS CPUs
172 - nios2 Files specific to Altera Nios-II CPUs
173 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
174 - pxa Files specific to Intel XScale PXA CPUs
175 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
176 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
177 - disk Code for disk drive partition handling
178 - doc Documentation (don't expect too much)
179 - drivers Commonly used device drivers
180 - dtt Digital Thermometer and Thermostat drivers
181 - examples Example code for standalone applications, etc.
182 - include Header Files
183 - lib_arm Files generic to ARM architecture
184 - lib_avr32 Files generic to AVR32 architecture
185 - lib_generic Files generic to all architectures
186 - lib_i386 Files generic to i386 architecture
187 - lib_m68k Files generic to m68k architecture
188 - lib_mips Files generic to MIPS architecture
189 - lib_nios Files generic to NIOS architecture
190 - lib_ppc Files generic to PowerPC architecture
191 - lib_sparc Files generic to SPARC architecture
192 - libfdt Library files to support flattened device trees
193 - net Networking code
194 - post Power On Self Test
195 - rtc Real Time Clock drivers
196 - tools Tools to build S-Record or U-Boot images, etc.
198 Software Configuration:
199 =======================
201 Configuration is usually done using C preprocessor defines; the
202 rationale behind that is to avoid dead code whenever possible.
204 There are two classes of configuration variables:
206 * Configuration _OPTIONS_:
207 These are selectable by the user and have names beginning with
210 * Configuration _SETTINGS_:
211 These depend on the hardware etc. and should not be meddled with if
212 you don't know what you're doing; they have names beginning with
215 Later we will add a configuration tool - probably similar to or even
216 identical to what's used for the Linux kernel. Right now, we have to
217 do the configuration by hand, which means creating some symbolic
218 links and editing some configuration files. We use the TQM8xxL boards
222 Selection of Processor Architecture and Board Type:
223 ---------------------------------------------------
225 For all supported boards there are ready-to-use default
226 configurations available; just type "make <board_name>_config".
228 Example: For a TQM823L module type:
233 For the Cogent platform, you need to specify the cpu type as well;
234 e.g. "make cogent_mpc8xx_config". And also configure the cogent
235 directory according to the instructions in cogent/README.
238 Configuration Options:
239 ----------------------
241 Configuration depends on the combination of board and CPU type; all
242 such information is kept in a configuration file
243 "include/configs/<board_name>.h".
245 Example: For a TQM823L module, all configuration settings are in
246 "include/configs/TQM823L.h".
249 Many of the options are named exactly as the corresponding Linux
250 kernel configuration options. The intention is to make it easier to
251 build a config tool - later.
254 The following options need to be configured:
256 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
258 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
260 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
261 Define exactly one, e.g. CONFIG_ATSTK1002
263 - CPU Module Type: (if CONFIG_COGENT is defined)
264 Define exactly one of
266 --- FIXME --- not tested yet:
267 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
268 CONFIG_CMA287_23, CONFIG_CMA287_50
270 - Motherboard Type: (if CONFIG_COGENT is defined)
271 Define exactly one of
272 CONFIG_CMA101, CONFIG_CMA102
274 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
275 Define one or more of
278 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
279 Define one or more of
280 CONFIG_LCD_HEARTBEAT - update a character position on
281 the lcd display every second with
284 - Board flavour: (if CONFIG_MPC8260ADS is defined)
287 CFG_8260ADS - original MPC8260ADS
288 CFG_8266ADS - MPC8266ADS
289 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
290 CFG_8272ADS - MPC8272ADS
292 - MPC824X Family Member (if CONFIG_MPC824X is defined)
293 Define exactly one of
294 CONFIG_MPC8240, CONFIG_MPC8245
296 - 8xx CPU Options: (if using an MPC8xx cpu)
297 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
298 get_gclk_freq() cannot work
299 e.g. if there is no 32KHz
300 reference PIT/RTC clock
301 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
304 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
307 CONFIG_8xx_CPUCLK_DEFAULT
308 See doc/README.MPC866
312 Define this to measure the actual CPU clock instead
313 of relying on the correctness of the configured
314 values. Mostly useful for board bringup to make sure
315 the PLL is locked at the intended frequency. Note
316 that this requires a (stable) reference clock (32 kHz
317 RTC clock or CFG_8XX_XIN)
319 - Intel Monahans options:
320 CFG_MONAHANS_RUN_MODE_OSC_RATIO
322 Defines the Monahans run mode to oscillator
323 ratio. Valid values are 8, 16, 24, 31. The core
324 frequency is this value multiplied by 13 MHz.
326 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
328 Defines the Monahans turbo mode to oscillator
329 ratio. Valid values are 1 (default if undefined) and
330 2. The core frequency as calculated above is multiplied
333 - Linux Kernel Interface:
336 U-Boot stores all clock information in Hz
337 internally. For binary compatibility with older Linux
338 kernels (which expect the clocks passed in the
339 bd_info data to be in MHz) the environment variable
340 "clocks_in_mhz" can be defined so that U-Boot
341 converts clock data to MHZ before passing it to the
343 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
344 "clocks_in_mhz=1" is automatically included in the
347 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
349 When transfering memsize parameter to linux, some versions
350 expect it to be in bytes, others in MB.
351 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
353 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
355 New kernel versions are expecting firmware settings to be
356 passed using flattened device trees (based on open firmware
360 * New libfdt-based support
361 * Adds the "fdt" command
362 * The bootm command automatically updates the fdt
365 * Deprecated, see CONFIG_OF_LIBFDT
366 * Original ft_build.c-based support
367 * Automatically modifies the dft as part of the bootm command
368 * The environment variable "disable_of", when set,
369 disables this functionality.
371 OF_CPU - The proper name of the cpus node.
372 OF_SOC - The proper name of the soc node.
373 OF_TBCLK - The timebase frequency.
374 OF_STDOUT_PATH - The path to the console device
376 boards with QUICC Engines require OF_QE to set UCC mac addresses
378 CONFIG_OF_BOARD_SETUP
380 Board code has addition modification that it wants to make
381 to the flat device tree before handing it off to the kernel
385 This define fills in the correct boot cpu in the boot
386 param header, the default value is zero if undefined.
391 Define this if you want support for Amba PrimeCell PL010 UARTs.
395 Define this if you want support for Amba PrimeCell PL011 UARTs.
399 If you have Amba PrimeCell PL011 UARTs, set this variable to
400 the clock speed of the UARTs.
404 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
405 define this to a list of base addresses for each (supported)
406 port. See e.g. include/configs/versatile.h
410 Depending on board, define exactly one serial port
411 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
412 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
413 console by defining CONFIG_8xx_CONS_NONE
415 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
416 port routines must be defined elsewhere
417 (i.e. serial_init(), serial_getc(), ...)
420 Enables console device for a color framebuffer. Needs following
421 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
422 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
424 VIDEO_HW_RECTFILL graphic chip supports
427 VIDEO_HW_BITBLT graphic chip supports
428 bit-blit (cf. smiLynxEM)
429 VIDEO_VISIBLE_COLS visible pixel columns
431 VIDEO_VISIBLE_ROWS visible pixel rows
432 VIDEO_PIXEL_SIZE bytes per pixel
433 VIDEO_DATA_FORMAT graphic data format
434 (0-5, cf. cfb_console.c)
435 VIDEO_FB_ADRS framebuffer address
436 VIDEO_KBD_INIT_FCT keyboard int fct
437 (i.e. i8042_kbd_init())
438 VIDEO_TSTC_FCT test char fct
440 VIDEO_GETC_FCT get char fct
442 CONFIG_CONSOLE_CURSOR cursor drawing on/off
443 (requires blink timer
445 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
446 CONFIG_CONSOLE_TIME display time/date info in
448 (requires CONFIG_CMD_DATE)
449 CONFIG_VIDEO_LOGO display Linux logo in
451 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
452 linux_logo.h for logo.
453 Requires CONFIG_VIDEO_LOGO
454 CONFIG_CONSOLE_EXTRA_INFO
455 addional board info beside
458 When CONFIG_CFB_CONSOLE is defined, video console is
459 default i/o. Serial console can be forced with
460 environment 'console=serial'.
462 When CONFIG_SILENT_CONSOLE is defined, all console
463 messages (by U-Boot and Linux!) can be silenced with
464 the "silent" environment variable. See
465 doc/README.silent for more information.
468 CONFIG_BAUDRATE - in bps
469 Select one of the baudrates listed in
470 CFG_BAUDRATE_TABLE, see below.
471 CFG_BRGCLK_PRESCALE, baudrate prescale
473 - Interrupt driven serial port input:
474 CONFIG_SERIAL_SOFTWARE_FIFO
477 Use an interrupt handler for receiving data on the
478 serial port. It also enables using hardware handshake
479 (RTS/CTS) and UART's built-in FIFO. Set the number of
480 bytes the interrupt driven input buffer should have.
482 Leave undefined to disable this feature, including
483 disable the buffer and hardware handshake.
485 - Console UART Number:
489 If defined internal UART1 (and not UART0) is used
490 as default U-Boot console.
492 - Boot Delay: CONFIG_BOOTDELAY - in seconds
493 Delay before automatically booting the default image;
494 set to -1 to disable autoboot.
496 See doc/README.autoboot for these options that
497 work with CONFIG_BOOTDELAY. None are required.
498 CONFIG_BOOT_RETRY_TIME
499 CONFIG_BOOT_RETRY_MIN
500 CONFIG_AUTOBOOT_KEYED
501 CONFIG_AUTOBOOT_PROMPT
502 CONFIG_AUTOBOOT_DELAY_STR
503 CONFIG_AUTOBOOT_STOP_STR
504 CONFIG_AUTOBOOT_DELAY_STR2
505 CONFIG_AUTOBOOT_STOP_STR2
506 CONFIG_ZERO_BOOTDELAY_CHECK
507 CONFIG_RESET_TO_RETRY
511 Only needed when CONFIG_BOOTDELAY is enabled;
512 define a command string that is automatically executed
513 when no character is read on the console interface
514 within "Boot Delay" after reset.
517 This can be used to pass arguments to the bootm
518 command. The value of CONFIG_BOOTARGS goes into the
519 environment value "bootargs".
521 CONFIG_RAMBOOT and CONFIG_NFSBOOT
522 The value of these goes into the environment as
523 "ramboot" and "nfsboot" respectively, and can be used
524 as a convenience, when switching between booting from
530 When this option is #defined, the existence of the
531 environment variable "preboot" will be checked
532 immediately before starting the CONFIG_BOOTDELAY
533 countdown and/or running the auto-boot command resp.
534 entering interactive mode.
536 This feature is especially useful when "preboot" is
537 automatically generated or modified. For an example
538 see the LWMON board specific code: here "preboot" is
539 modified when the user holds down a certain
540 combination of keys on the (special) keyboard when
543 - Serial Download Echo Mode:
545 If defined to 1, all characters received during a
546 serial download (using the "loads" command) are
547 echoed back. This might be needed by some terminal
548 emulations (like "cu"), but may as well just take
549 time on others. This setting #define's the initial
550 value of the "loads_echo" environment variable.
552 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
554 Select one of the baudrates listed in
555 CFG_BAUDRATE_TABLE, see below.
558 Monitor commands can be included or excluded
559 from the build by using the #include files
560 "config_cmd_all.h" and #undef'ing unwanted
561 commands, or using "config_cmd_default.h"
562 and augmenting with additional #define's
565 The default command configuration includes all commands
566 except those marked below with a "*".
568 CONFIG_CMD_ASKENV * ask for env variable
569 CONFIG_CMD_AUTOSCRIPT Autoscript Support
570 CONFIG_CMD_BDI bdinfo
571 CONFIG_CMD_BEDBUG * Include BedBug Debugger
572 CONFIG_CMD_BMP * BMP support
573 CONFIG_CMD_BSP * Board specific commands
574 CONFIG_CMD_BOOTD bootd
575 CONFIG_CMD_CACHE * icache, dcache
576 CONFIG_CMD_CONSOLE coninfo
577 CONFIG_CMD_DATE * support for RTC, date/time...
578 CONFIG_CMD_DHCP * DHCP support
579 CONFIG_CMD_DIAG * Diagnostics
580 CONFIG_CMD_DOC * Disk-On-Chip Support
581 CONFIG_CMD_DTT * Digital Therm and Thermostat
582 CONFIG_CMD_ECHO echo arguments
583 CONFIG_CMD_EEPROM * EEPROM read/write support
584 CONFIG_CMD_ELF * bootelf, bootvx
585 CONFIG_CMD_ENV saveenv
586 CONFIG_CMD_FDC * Floppy Disk Support
587 CONFIG_CMD_FAT * FAT partition support
588 CONFIG_CMD_FDOS * Dos diskette Support
589 CONFIG_CMD_FLASH flinfo, erase, protect
590 CONFIG_CMD_FPGA FPGA device initialization support
591 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
592 CONFIG_CMD_I2C * I2C serial bus support
593 CONFIG_CMD_IDE * IDE harddisk support
594 CONFIG_CMD_IMI iminfo
595 CONFIG_CMD_IMLS List all found images
596 CONFIG_CMD_IMMAP * IMMR dump support
597 CONFIG_CMD_IRQ * irqinfo
598 CONFIG_CMD_ITEST Integer/string test of 2 values
599 CONFIG_CMD_JFFS2 * JFFS2 Support
600 CONFIG_CMD_KGDB * kgdb
601 CONFIG_CMD_LOADB loadb
602 CONFIG_CMD_LOADS loads
603 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
605 CONFIG_CMD_MISC Misc functions like sleep etc
606 CONFIG_CMD_MMC * MMC memory mapped support
607 CONFIG_CMD_MII * MII utility commands
608 CONFIG_CMD_NAND * NAND support
609 CONFIG_CMD_NET bootp, tftpboot, rarpboot
610 CONFIG_CMD_PCI * pciinfo
611 CONFIG_CMD_PCMCIA * PCMCIA support
612 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
614 CONFIG_CMD_PORTIO * Port I/O
615 CONFIG_CMD_REGINFO * Register dump
616 CONFIG_CMD_RUN run command in env variable
617 CONFIG_CMD_SAVES * save S record dump
618 CONFIG_CMD_SCSI * SCSI Support
619 CONFIG_CMD_SDRAM * print SDRAM configuration information
620 (requires CONFIG_CMD_I2C)
621 CONFIG_CMD_SETGETDCR Support for DCR Register access
623 CONFIG_CMD_SPI * SPI serial bus support
624 CONFIG_CMD_USB * USB support
625 CONFIG_CMD_VFD * VFD support (TRAB)
626 CONFIG_CMD_BSP * Board SPecific functions
627 CONFIG_CMD_CDP * Cisco Discover Protocol support
628 CONFIG_CMD_FSL * Microblaze FSL support
631 EXAMPLE: If you want all functions except of network
632 support you can write:
634 #include "config_cmd_all.h"
635 #undef CONFIG_CMD_NET
638 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
640 Note: Don't enable the "icache" and "dcache" commands
641 (configuration option CONFIG_CMD_CACHE) unless you know
642 what you (and your U-Boot users) are doing. Data
643 cache cannot be enabled on systems like the 8xx or
644 8260 (where accesses to the IMMR region must be
645 uncached), and it cannot be disabled on all other
646 systems where we (mis-) use the data cache to hold an
647 initial stack and some data.
650 XXX - this list needs to get updated!
654 If this variable is defined, it enables watchdog
655 support. There must be support in the platform specific
656 code for a watchdog. For the 8xx and 8260 CPUs, the
657 SIU Watchdog feature is enabled in the SYPCR
661 CONFIG_VERSION_VARIABLE
662 If this variable is defined, an environment variable
663 named "ver" is created by U-Boot showing the U-Boot
664 version as printed by the "version" command.
665 This variable is readonly.
669 When CONFIG_CMD_DATE is selected, the type of the RTC
670 has to be selected, too. Define exactly one of the
673 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
674 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
675 CONFIG_RTC_MC13783 - use MC13783 RTC
676 CONFIG_RTC_MC146818 - use MC146818 RTC
677 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
678 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
679 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
680 CONFIG_RTC_DS164x - use Dallas DS164x RTC
681 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
682 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
683 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
685 Note that if the RTC uses I2C, then the I2C interface
686 must also be configured. See I2C Support, below.
690 When CONFIG_TIMESTAMP is selected, the timestamp
691 (date and time) of an image is printed by image
692 commands like bootm or iminfo. This option is
693 automatically enabled when you select CONFIG_CMD_DATE .
696 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
697 and/or CONFIG_ISO_PARTITION
699 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
700 CONFIG_CMD_SCSI) you must configure support for at
701 least one partition type as well.
704 CONFIG_IDE_RESET_ROUTINE - this is defined in several
705 board configurations files but used nowhere!
707 CONFIG_IDE_RESET - is this is defined, IDE Reset will
708 be performed by calling the function
709 ide_set_reset(int reset)
710 which has to be defined in a board specific file
715 Set this to enable ATAPI support.
720 Set this to enable support for disks larger than 137GB
721 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
722 Whithout these , LBA48 support uses 32bit variables and will 'only'
723 support disks up to 2.1TB.
726 When enabled, makes the IDE subsystem use 64bit sector addresses.
730 At the moment only there is only support for the
731 SYM53C8XX SCSI controller; define
732 CONFIG_SCSI_SYM53C8XX to enable it.
734 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
735 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
736 CFG_SCSI_MAX_LUN] can be adjusted to define the
737 maximum numbers of LUNs, SCSI ID's and target
739 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
741 - NETWORK Support (PCI):
743 Support for Intel 8254x gigabit chips.
745 CONFIG_E1000_FALLBACK_MAC
746 default MAC for empty eeprom after production.
749 Support for Intel 82557/82559/82559ER chips.
750 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
751 write routine for first time initialisation.
754 Support for Digital 2114x chips.
755 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
756 modem chip initialisation (KS8761/QS6611).
759 Support for National dp83815 chips.
762 Support for National dp8382[01] gigabit chips.
764 - NETWORK Support (other):
766 CONFIG_DRIVER_LAN91C96
767 Support for SMSC's LAN91C96 chips.
770 Define this to hold the physical address
771 of the LAN91C96's I/O space
773 CONFIG_LAN91C96_USE_32_BIT
774 Define this to enable 32 bit addressing
776 CONFIG_DRIVER_SMC91111
777 Support for SMSC's LAN91C111 chip
780 Define this to hold the physical address
781 of the device (I/O space)
783 CONFIG_SMC_USE_32_BIT
784 Define this if data bus is 32 bits
786 CONFIG_SMC_USE_IOFUNCS
787 Define this to use i/o functions instead of macros
788 (some hardware wont work with macros)
791 At the moment only the UHCI host controller is
792 supported (PIP405, MIP405, MPC5200); define
793 CONFIG_USB_UHCI to enable it.
794 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
795 and define CONFIG_USB_STORAGE to enable the USB
798 Supported are USB Keyboards and USB Floppy drives
800 MPC5200 USB requires additional defines:
802 for 528 MHz Clock: 0x0001bbbb
804 for differential drivers: 0x00001000
805 for single ended drivers: 0x00005000
807 May be defined to allow interrupt polling
808 instead of using asynchronous interrupts
811 Define the below if you wish to use the USB console.
812 Once firmware is rebuilt from a serial console issue the
813 command "setenv stdin usbtty; setenv stdout usbtty" and
814 attach your usb cable. The Unix command "dmesg" should print
815 it has found a new device. The environment variable usbtty
816 can be set to gserial or cdc_acm to enable your device to
817 appear to a USB host as a Linux gserial device or a
818 Common Device Class Abstract Control Model serial device.
819 If you select usbtty = gserial you should be able to enumerate
821 # modprobe usbserial vendor=0xVendorID product=0xProductID
822 else if using cdc_acm, simply setting the environment
823 variable usbtty to be cdc_acm should suffice. The following
824 might be defined in YourBoardName.h
827 Define this to build a UDC device
830 Define this to have a tty type of device available to
831 talk to the UDC device
833 CFG_CONSOLE_IS_IN_ENV
834 Define this if you want stdin, stdout &/or stderr to
838 CFG_USB_EXTC_CLK 0xBLAH
839 Derive USB clock from external clock "blah"
840 - CFG_USB_EXTC_CLK 0x02
842 CFG_USB_BRG_CLK 0xBLAH
843 Derive USB clock from brgclk
844 - CFG_USB_BRG_CLK 0x04
846 If you have a USB-IF assigned VendorID then you may wish to
847 define your own vendor specific values either in BoardName.h
848 or directly in usbd_vendor_info.h. If you don't define
849 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
850 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
851 should pretend to be a Linux device to it's target host.
853 CONFIG_USBD_MANUFACTURER
854 Define this string as the name of your company for
855 - CONFIG_USBD_MANUFACTURER "my company"
857 CONFIG_USBD_PRODUCT_NAME
858 Define this string as the name of your product
859 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
862 Define this as your assigned Vendor ID from the USB
863 Implementors Forum. This *must* be a genuine Vendor ID
864 to avoid polluting the USB namespace.
865 - CONFIG_USBD_VENDORID 0xFFFF
867 CONFIG_USBD_PRODUCTID
868 Define this as the unique Product ID
870 - CONFIG_USBD_PRODUCTID 0xFFFF
874 The MMC controller on the Intel PXA is supported. To
875 enable this define CONFIG_MMC. The MMC can be
876 accessed from the boot prompt by mapping the device
877 to physical memory similar to flash. Command line is
878 enabled with CONFIG_CMD_MMC. The MMC driver also works with
879 the FAT fs. This is enabled with CONFIG_CMD_FAT.
881 - Journaling Flash filesystem support:
882 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
883 CONFIG_JFFS2_NAND_DEV
884 Define these for a default partition on a NAND device
886 CFG_JFFS2_FIRST_SECTOR,
887 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
888 Define these for a default partition on a NOR device
891 Define this to create an own partition. You have to provide a
892 function struct part_info* jffs2_part_info(int part_num)
894 If you define only one JFFS2 partition you may also want to
895 #define CFG_JFFS_SINGLE_PART 1
896 to disable the command chpart. This is the default when you
897 have not defined a custom partition
902 Define this to enable standard (PC-Style) keyboard
906 Standard PC keyboard driver with US (is default) and
907 GERMAN key layout (switch via environment 'keymap=de') support.
908 Export function i8042_kbd_init, i8042_tstc and i8042_getc
909 for cfb_console. Supports cursor blinking.
914 Define this to enable video support (for output to
919 Enable Chips & Technologies 69000 Video chip
921 CONFIG_VIDEO_SMI_LYNXEM
922 Enable Silicon Motion SMI 712/710/810 Video chip. The
923 video output is selected via environment 'videoout'
924 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
927 For the CT69000 and SMI_LYNXEM drivers, videomode is
928 selected via environment 'videomode'. Two diferent ways
930 - "videomode=num" 'num' is a standard LiLo mode numbers.
931 Following standard modes are supported (* is default):
933 Colors 640x480 800x600 1024x768 1152x864 1280x1024
934 -------------+---------------------------------------------
935 8 bits | 0x301* 0x303 0x305 0x161 0x307
936 15 bits | 0x310 0x313 0x316 0x162 0x319
937 16 bits | 0x311 0x314 0x317 0x163 0x31A
938 24 bits | 0x312 0x315 0x318 ? 0x31B
939 -------------+---------------------------------------------
940 (i.e. setenv videomode 317; saveenv; reset;)
942 - "videomode=bootargs" all the video parameters are parsed
943 from the bootargs. (See drivers/video/videomodes.c)
946 CONFIG_VIDEO_SED13806
947 Enable Epson SED13806 driver. This driver supports 8bpp
948 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
949 or CONFIG_VIDEO_SED13806_16BPP
954 Define this to enable a custom keyboard support.
955 This simply calls drv_keyboard_init() which must be
956 defined in your board-specific files.
957 The only board using this so far is RBC823.
959 - LCD Support: CONFIG_LCD
961 Define this to enable LCD support (for output to LCD
962 display); also select one of the supported displays
963 by defining one of these:
967 HITACHI TX09D70VM1CCA, 3.5", 240x320.
969 CONFIG_NEC_NL6448AC33:
971 NEC NL6448AC33-18. Active, color, single scan.
973 CONFIG_NEC_NL6448BC20
975 NEC NL6448BC20-08. 6.5", 640x480.
976 Active, color, single scan.
978 CONFIG_NEC_NL6448BC33_54
980 NEC NL6448BC33-54. 10.4", 640x480.
981 Active, color, single scan.
985 Sharp 320x240. Active, color, single scan.
986 It isn't 16x9, and I am not sure what it is.
988 CONFIG_SHARP_LQ64D341
990 Sharp LQ64D341 display, 640x480.
991 Active, color, single scan.
995 HLD1045 display, 640x480.
996 Active, color, single scan.
1000 Optrex CBL50840-2 NF-FW 99 22 M5
1002 Hitachi LMG6912RPFC-00T
1006 320x240. Black & white.
1008 Normally display is black on white background; define
1009 CFG_WHITE_ON_BLACK to get it inverted.
1011 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1013 If this option is set, the environment is checked for
1014 a variable "splashimage". If found, the usual display
1015 of logo, copyright and system information on the LCD
1016 is suppressed and the BMP image at the address
1017 specified in "splashimage" is loaded instead. The
1018 console is redirected to the "nulldev", too. This
1019 allows for a "silent" boot where a splash screen is
1020 loaded very quickly after power-on.
1022 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1024 If this option is set, additionally to standard BMP
1025 images, gzipped BMP images can be displayed via the
1026 splashscreen support or the bmp command.
1028 - Compression support:
1031 If this option is set, support for bzip2 compressed
1032 images is included. If not, only uncompressed and gzip
1033 compressed images are supported.
1035 NOTE: the bzip2 algorithm requires a lot of RAM, so
1036 the malloc area (as defined by CFG_MALLOC_LEN) should
1042 The address of PHY on MII bus.
1044 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1046 The clock frequency of the MII bus
1050 If this option is set, support for speed/duplex
1051 detection of Gigabit PHY is included.
1053 CONFIG_PHY_RESET_DELAY
1055 Some PHY like Intel LXT971A need extra delay after
1056 reset before any MII register access is possible.
1057 For such PHY, set this option to the usec delay
1058 required. (minimum 300usec for LXT971A)
1060 CONFIG_PHY_CMD_DELAY (ppc4xx)
1062 Some PHY like Intel LXT971A need extra delay after
1063 command issued before MII status register can be read
1070 Define a default value for ethernet address to use
1071 for the respective ethernet interface, in case this
1072 is not determined automatically.
1077 Define a default value for the IP address to use for
1078 the default ethernet interface, in case this is not
1079 determined through e.g. bootp.
1081 - Server IP address:
1084 Defines a default value for theIP address of a TFTP
1085 server to contact when using the "tftboot" command.
1087 - Multicast TFTP Mode:
1090 Defines whether you want to support multicast TFTP as per
1091 rfc-2090; for example to work with atftp. Lets lots of targets
1092 tftp down the same boot image concurrently. Note: the ethernet
1093 driver in use must provide a function: mcast() to join/leave a
1096 CONFIG_BOOTP_RANDOM_DELAY
1097 - BOOTP Recovery Mode:
1098 CONFIG_BOOTP_RANDOM_DELAY
1100 If you have many targets in a network that try to
1101 boot using BOOTP, you may want to avoid that all
1102 systems send out BOOTP requests at precisely the same
1103 moment (which would happen for instance at recovery
1104 from a power failure, when all systems will try to
1105 boot, thus flooding the BOOTP server. Defining
1106 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1107 inserted before sending out BOOTP requests. The
1108 following delays are inserted then:
1110 1st BOOTP request: delay 0 ... 1 sec
1111 2nd BOOTP request: delay 0 ... 2 sec
1112 3rd BOOTP request: delay 0 ... 4 sec
1114 BOOTP requests: delay 0 ... 8 sec
1116 - DHCP Advanced Options:
1117 You can fine tune the DHCP functionality by defining
1118 CONFIG_BOOTP_* symbols:
1120 CONFIG_BOOTP_SUBNETMASK
1121 CONFIG_BOOTP_GATEWAY
1122 CONFIG_BOOTP_HOSTNAME
1123 CONFIG_BOOTP_NISDOMAIN
1124 CONFIG_BOOTP_BOOTPATH
1125 CONFIG_BOOTP_BOOTFILESIZE
1128 CONFIG_BOOTP_SEND_HOSTNAME
1129 CONFIG_BOOTP_NTPSERVER
1130 CONFIG_BOOTP_TIMEOFFSET
1131 CONFIG_BOOTP_VENDOREX
1133 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1134 environment variable, not the BOOTP server.
1136 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1137 serverip from a DHCP server, it is possible that more
1138 than one DNS serverip is offered to the client.
1139 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1140 serverip will be stored in the additional environment
1141 variable "dnsip2". The first DNS serverip is always
1142 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1145 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1146 to do a dynamic update of a DNS server. To do this, they
1147 need the hostname of the DHCP requester.
1148 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1149 of the "hostname" environment variable is passed as
1150 option 12 to the DHCP server.
1152 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1154 A 32bit value in microseconds for a delay between
1155 receiving a "DHCP Offer" and sending the "DHCP Request".
1156 This fixes a problem with certain DHCP servers that don't
1157 respond 100% of the time to a "DHCP request". E.g. On an
1158 AT91RM9200 processor running at 180MHz, this delay needed
1159 to be *at least* 15,000 usec before a Windows Server 2003
1160 DHCP server would reply 100% of the time. I recommend at
1161 least 50,000 usec to be safe. The alternative is to hope
1162 that one of the retries will be successful but note that
1163 the DHCP timeout and retry process takes a longer than
1167 CONFIG_CDP_DEVICE_ID
1169 The device id used in CDP trigger frames.
1171 CONFIG_CDP_DEVICE_ID_PREFIX
1173 A two character string which is prefixed to the MAC address
1178 A printf format string which contains the ascii name of
1179 the port. Normally is set to "eth%d" which sets
1180 eth0 for the first ethernet, eth1 for the second etc.
1182 CONFIG_CDP_CAPABILITIES
1184 A 32bit integer which indicates the device capabilities;
1185 0x00000010 for a normal host which does not forwards.
1189 An ascii string containing the version of the software.
1193 An ascii string containing the name of the platform.
1197 A 32bit integer sent on the trigger.
1199 CONFIG_CDP_POWER_CONSUMPTION
1201 A 16bit integer containing the power consumption of the
1202 device in .1 of milliwatts.
1204 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1206 A byte containing the id of the VLAN.
1208 - Status LED: CONFIG_STATUS_LED
1210 Several configurations allow to display the current
1211 status using a LED. For instance, the LED will blink
1212 fast while running U-Boot code, stop blinking as
1213 soon as a reply to a BOOTP request was received, and
1214 start blinking slow once the Linux kernel is running
1215 (supported by a status LED driver in the Linux
1216 kernel). Defining CONFIG_STATUS_LED enables this
1219 - CAN Support: CONFIG_CAN_DRIVER
1221 Defining CONFIG_CAN_DRIVER enables CAN driver support
1222 on those systems that support this (optional)
1223 feature, like the TQM8xxL modules.
1225 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1227 These enable I2C serial bus commands. Defining either of
1228 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1229 include the appropriate I2C driver for the selected cpu.
1231 This will allow you to use i2c commands at the u-boot
1232 command line (as long as you set CONFIG_CMD_I2C in
1233 CONFIG_COMMANDS) and communicate with i2c based realtime
1234 clock chips. See common/cmd_i2c.c for a description of the
1235 command line interface.
1237 CONFIG_I2C_CMD_TREE is a recommended option that places
1238 all I2C commands under a single 'i2c' root command. The
1239 older 'imm', 'imd', 'iprobe' etc. commands are considered
1240 deprecated and may disappear in the future.
1242 CONFIG_HARD_I2C selects a hardware I2C controller.
1244 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1245 bit-banging) driver instead of CPM or similar hardware
1248 There are several other quantities that must also be
1249 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1251 In both cases you will need to define CFG_I2C_SPEED
1252 to be the frequency (in Hz) at which you wish your i2c bus
1253 to run and CFG_I2C_SLAVE to be the address of this node (ie
1254 the cpu's i2c node address).
1256 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1257 sets the cpu up as a master node and so its address should
1258 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1259 p.16-473). So, set CFG_I2C_SLAVE to 0.
1261 That's all that's required for CONFIG_HARD_I2C.
1263 If you use the software i2c interface (CONFIG_SOFT_I2C)
1264 then the following macros need to be defined (examples are
1265 from include/configs/lwmon.h):
1269 (Optional). Any commands necessary to enable the I2C
1270 controller or configure ports.
1272 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1276 (Only for MPC8260 CPU). The I/O port to use (the code
1277 assumes both bits are on the same port). Valid values
1278 are 0..3 for ports A..D.
1282 The code necessary to make the I2C data line active
1283 (driven). If the data line is open collector, this
1286 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1290 The code necessary to make the I2C data line tri-stated
1291 (inactive). If the data line is open collector, this
1294 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1298 Code that returns TRUE if the I2C data line is high,
1301 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1305 If <bit> is TRUE, sets the I2C data line high. If it
1306 is FALSE, it clears it (low).
1308 eg: #define I2C_SDA(bit) \
1309 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1310 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1314 If <bit> is TRUE, sets the I2C clock line high. If it
1315 is FALSE, it clears it (low).
1317 eg: #define I2C_SCL(bit) \
1318 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1319 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1323 This delay is invoked four times per clock cycle so this
1324 controls the rate of data transfer. The data rate thus
1325 is 1 / (I2C_DELAY * 4). Often defined to be something
1328 #define I2C_DELAY udelay(2)
1332 When a board is reset during an i2c bus transfer
1333 chips might think that the current transfer is still
1334 in progress. On some boards it is possible to access
1335 the i2c SCLK line directly, either by using the
1336 processor pin as a GPIO or by having a second pin
1337 connected to the bus. If this option is defined a
1338 custom i2c_init_board() routine in boards/xxx/board.c
1339 is run early in the boot sequence.
1341 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1343 This option enables configuration of bi_iic_fast[] flags
1344 in u-boot bd_info structure based on u-boot environment
1345 variable "i2cfast". (see also i2cfast)
1347 CONFIG_I2C_MULTI_BUS
1349 This option allows the use of multiple I2C buses, each of which
1350 must have a controller. At any point in time, only one bus is
1351 active. To switch to a different bus, use the 'i2c dev' command.
1352 Note that bus numbering is zero-based.
1356 This option specifies a list of I2C devices that will be skipped
1357 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1358 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1359 pairs. Otherwise, specify a 1D array of device addresses
1362 #undef CONFIG_I2C_MULTI_BUS
1363 #define CFG_I2C_NOPROBES {0x50,0x68}
1365 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1367 #define CONFIG_I2C_MULTI_BUS
1368 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1370 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1374 If defined, then this indicates the I2C bus number for DDR SPD.
1375 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1379 If defined, then this indicates the I2C bus number for the RTC.
1380 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1384 If defined, then this indicates the I2C bus number for the DTT.
1385 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1389 Define this option if you want to use Freescale's I2C driver in
1390 drivers/i2c/fsl_i2c.c.
1393 - SPI Support: CONFIG_SPI
1395 Enables SPI driver (so far only tested with
1396 SPI EEPROM, also an instance works with Crystal A/D and
1397 D/As on the SACSng board)
1401 Enables extended (16-bit) SPI EEPROM addressing.
1402 (symmetrical to CONFIG_I2C_X)
1406 Enables a software (bit-bang) SPI driver rather than
1407 using hardware support. This is a general purpose
1408 driver that only requires three general I/O port pins
1409 (two outputs, one input) to function. If this is
1410 defined, the board configuration must define several
1411 SPI configuration items (port pins to use, etc). For
1412 an example, see include/configs/sacsng.h.
1416 Enables a hardware SPI driver for general-purpose reads
1417 and writes. As with CONFIG_SOFT_SPI, the board configuration
1418 must define a list of chip-select function pointers.
1419 Currently supported on some MPC8xxx processors. For an
1420 example, see include/configs/mpc8349emds.h.
1424 Enables the driver for the SPI controllers on i.MX and MXC
1425 SoCs. Currently only i.MX31 is supported.
1427 - FPGA Support: CONFIG_FPGA
1429 Enables FPGA subsystem.
1431 CONFIG_FPGA_<vendor>
1433 Enables support for specific chip vendors.
1436 CONFIG_FPGA_<family>
1438 Enables support for FPGA family.
1439 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1443 Specify the number of FPGA devices to support.
1445 CFG_FPGA_PROG_FEEDBACK
1447 Enable printing of hash marks during FPGA configuration.
1451 Enable checks on FPGA configuration interface busy
1452 status by the configuration function. This option
1453 will require a board or device specific function to
1458 If defined, a function that provides delays in the FPGA
1459 configuration driver.
1461 CFG_FPGA_CHECK_CTRLC
1462 Allow Control-C to interrupt FPGA configuration
1464 CFG_FPGA_CHECK_ERROR
1466 Check for configuration errors during FPGA bitfile
1467 loading. For example, abort during Virtex II
1468 configuration if the INIT_B line goes low (which
1469 indicated a CRC error).
1473 Maximum time to wait for the INIT_B line to deassert
1474 after PROB_B has been deasserted during a Virtex II
1475 FPGA configuration sequence. The default time is 500
1480 Maximum time to wait for BUSY to deassert during
1481 Virtex II FPGA configuration. The default is 5 mS.
1483 CFG_FPGA_WAIT_CONFIG
1485 Time to wait after FPGA configuration. The default is
1488 - Configuration Management:
1491 If defined, this string will be added to the U-Boot
1492 version information (U_BOOT_VERSION)
1494 - Vendor Parameter Protection:
1496 U-Boot considers the values of the environment
1497 variables "serial#" (Board Serial Number) and
1498 "ethaddr" (Ethernet Address) to be parameters that
1499 are set once by the board vendor / manufacturer, and
1500 protects these variables from casual modification by
1501 the user. Once set, these variables are read-only,
1502 and write or delete attempts are rejected. You can
1503 change this behviour:
1505 If CONFIG_ENV_OVERWRITE is #defined in your config
1506 file, the write protection for vendor parameters is
1507 completely disabled. Anybody can change or delete
1510 Alternatively, if you #define _both_ CONFIG_ETHADDR
1511 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1512 ethernet address is installed in the environment,
1513 which can be changed exactly ONCE by the user. [The
1514 serial# is unaffected by this, i. e. it remains
1520 Define this variable to enable the reservation of
1521 "protected RAM", i. e. RAM which is not overwritten
1522 by U-Boot. Define CONFIG_PRAM to hold the number of
1523 kB you want to reserve for pRAM. You can overwrite
1524 this default value by defining an environment
1525 variable "pram" to the number of kB you want to
1526 reserve. Note that the board info structure will
1527 still show the full amount of RAM. If pRAM is
1528 reserved, a new environment variable "mem" will
1529 automatically be defined to hold the amount of
1530 remaining RAM in a form that can be passed as boot
1531 argument to Linux, for instance like that:
1533 setenv bootargs ... mem=\${mem}
1536 This way you can tell Linux not to use this memory,
1537 either, which results in a memory region that will
1538 not be affected by reboots.
1540 *WARNING* If your board configuration uses automatic
1541 detection of the RAM size, you must make sure that
1542 this memory test is non-destructive. So far, the
1543 following board configurations are known to be
1546 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1547 HERMES, IP860, RPXlite, LWMON, LANTEC,
1548 PCU_E, FLAGADM, TQM8260
1553 Define this variable to stop the system in case of a
1554 fatal error, so that you have to reset it manually.
1555 This is probably NOT a good idea for an embedded
1556 system where you want to system to reboot
1557 automatically as fast as possible, but it may be
1558 useful during development since you can try to debug
1559 the conditions that lead to the situation.
1561 CONFIG_NET_RETRY_COUNT
1563 This variable defines the number of retries for
1564 network operations like ARP, RARP, TFTP, or BOOTP
1565 before giving up the operation. If not defined, a
1566 default value of 5 is used.
1570 Timeout waiting for an ARP reply in milliseconds.
1572 - Command Interpreter:
1573 CONFIG_AUTO_COMPLETE
1575 Enable auto completion of commands using TAB.
1577 Note that this feature has NOT been implemented yet
1578 for the "hush" shell.
1583 Define this variable to enable the "hush" shell (from
1584 Busybox) as command line interpreter, thus enabling
1585 powerful command line syntax like
1586 if...then...else...fi conditionals or `&&' and '||'
1587 constructs ("shell scripts").
1589 If undefined, you get the old, much simpler behaviour
1590 with a somewhat smaller memory footprint.
1595 This defines the secondary prompt string, which is
1596 printed when the command interpreter needs more input
1597 to complete a command. Usually "> ".
1601 In the current implementation, the local variables
1602 space and global environment variables space are
1603 separated. Local variables are those you define by
1604 simply typing `name=value'. To access a local
1605 variable later on, you have write `$name' or
1606 `${name}'; to execute the contents of a variable
1607 directly type `$name' at the command prompt.
1609 Global environment variables are those you use
1610 setenv/printenv to work with. To run a command stored
1611 in such a variable, you need to use the run command,
1612 and you must not use the '$' sign to access them.
1614 To store commands and special characters in a
1615 variable, please use double quotation marks
1616 surrounding the whole text of the variable, instead
1617 of the backslashes before semicolons and special
1620 - Commandline Editing and History:
1621 CONFIG_CMDLINE_EDITING
1623 Enable editiong and History functions for interactive
1624 commandline input operations
1626 - Default Environment:
1627 CONFIG_EXTRA_ENV_SETTINGS
1629 Define this to contain any number of null terminated
1630 strings (variable = value pairs) that will be part of
1631 the default environment compiled into the boot image.
1633 For example, place something like this in your
1634 board's config file:
1636 #define CONFIG_EXTRA_ENV_SETTINGS \
1640 Warning: This method is based on knowledge about the
1641 internal format how the environment is stored by the
1642 U-Boot code. This is NOT an official, exported
1643 interface! Although it is unlikely that this format
1644 will change soon, there is no guarantee either.
1645 You better know what you are doing here.
1647 Note: overly (ab)use of the default environment is
1648 discouraged. Make sure to check other ways to preset
1649 the environment like the autoscript function or the
1652 - DataFlash Support:
1653 CONFIG_HAS_DATAFLASH
1655 Defining this option enables DataFlash features and
1656 allows to read/write in Dataflash via the standard
1659 - SystemACE Support:
1662 Adding this option adds support for Xilinx SystemACE
1663 chips attached via some sort of local bus. The address
1664 of the chip must alsh be defined in the
1665 CFG_SYSTEMACE_BASE macro. For example:
1667 #define CONFIG_SYSTEMACE
1668 #define CFG_SYSTEMACE_BASE 0xf0000000
1670 When SystemACE support is added, the "ace" device type
1671 becomes available to the fat commands, i.e. fatls.
1673 - TFTP Fixed UDP Port:
1676 If this is defined, the environment variable tftpsrcp
1677 is used to supply the TFTP UDP source port value.
1678 If tftpsrcp isn't defined, the normal pseudo-random port
1679 number generator is used.
1681 Also, the environment variable tftpdstp is used to supply
1682 the TFTP UDP destination port value. If tftpdstp isn't
1683 defined, the normal port 69 is used.
1685 The purpose for tftpsrcp is to allow a TFTP server to
1686 blindly start the TFTP transfer using the pre-configured
1687 target IP address and UDP port. This has the effect of
1688 "punching through" the (Windows XP) firewall, allowing
1689 the remainder of the TFTP transfer to proceed normally.
1690 A better solution is to properly configure the firewall,
1691 but sometimes that is not allowed.
1693 - Show boot progress:
1694 CONFIG_SHOW_BOOT_PROGRESS
1696 Defining this option allows to add some board-
1697 specific code (calling a user-provided function
1698 "show_boot_progress(int)") that enables you to show
1699 the system's boot progress on some display (for
1700 example, some LED's) on your board. At the moment,
1701 the following checkpoints are implemented:
1703 Legacy uImage format:
1706 1 common/cmd_bootm.c before attempting to boot an image
1707 -1 common/cmd_bootm.c Image header has bad magic number
1708 2 common/cmd_bootm.c Image header has correct magic number
1709 -2 common/cmd_bootm.c Image header has bad checksum
1710 3 common/cmd_bootm.c Image header has correct checksum
1711 -3 common/cmd_bootm.c Image data has bad checksum
1712 4 common/cmd_bootm.c Image data has correct checksum
1713 -4 common/cmd_bootm.c Image is for unsupported architecture
1714 5 common/cmd_bootm.c Architecture check OK
1715 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1716 6 common/cmd_bootm.c Image Type check OK
1717 -6 common/cmd_bootm.c gunzip uncompression error
1718 -7 common/cmd_bootm.c Unimplemented compression type
1719 7 common/cmd_bootm.c Uncompression OK
1720 8 common/cmd_bootm.c No uncompress/copy overwrite error
1721 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1723 9 common/image.c Start initial ramdisk verification
1724 -10 common/image.c Ramdisk header has bad magic number
1725 -11 common/image.c Ramdisk header has bad checksum
1726 10 common/image.c Ramdisk header is OK
1727 -12 common/image.c Ramdisk data has bad checksum
1728 11 common/image.c Ramdisk data has correct checksum
1729 12 common/image.c Ramdisk verification complete, start loading
1730 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1731 13 common/image.c Start multifile image verification
1732 14 common/image.c No initial ramdisk, no multifile, continue.
1734 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1736 -30 lib_ppc/board.c Fatal error, hang the system
1737 -31 post/post.c POST test failed, detected by post_output_backlog()
1738 -32 post/post.c POST test failed, detected by post_run_single()
1740 34 common/cmd_doc.c before loading a Image from a DOC device
1741 -35 common/cmd_doc.c Bad usage of "doc" command
1742 35 common/cmd_doc.c correct usage of "doc" command
1743 -36 common/cmd_doc.c No boot device
1744 36 common/cmd_doc.c correct boot device
1745 -37 common/cmd_doc.c Unknown Chip ID on boot device
1746 37 common/cmd_doc.c correct chip ID found, device available
1747 -38 common/cmd_doc.c Read Error on boot device
1748 38 common/cmd_doc.c reading Image header from DOC device OK
1749 -39 common/cmd_doc.c Image header has bad magic number
1750 39 common/cmd_doc.c Image header has correct magic number
1751 -40 common/cmd_doc.c Error reading Image from DOC device
1752 40 common/cmd_doc.c Image header has correct magic number
1753 41 common/cmd_ide.c before loading a Image from a IDE device
1754 -42 common/cmd_ide.c Bad usage of "ide" command
1755 42 common/cmd_ide.c correct usage of "ide" command
1756 -43 common/cmd_ide.c No boot device
1757 43 common/cmd_ide.c boot device found
1758 -44 common/cmd_ide.c Device not available
1759 44 common/cmd_ide.c Device available
1760 -45 common/cmd_ide.c wrong partition selected
1761 45 common/cmd_ide.c partition selected
1762 -46 common/cmd_ide.c Unknown partition table
1763 46 common/cmd_ide.c valid partition table found
1764 -47 common/cmd_ide.c Invalid partition type
1765 47 common/cmd_ide.c correct partition type
1766 -48 common/cmd_ide.c Error reading Image Header on boot device
1767 48 common/cmd_ide.c reading Image Header from IDE device OK
1768 -49 common/cmd_ide.c Image header has bad magic number
1769 49 common/cmd_ide.c Image header has correct magic number
1770 -50 common/cmd_ide.c Image header has bad checksum
1771 50 common/cmd_ide.c Image header has correct checksum
1772 -51 common/cmd_ide.c Error reading Image from IDE device
1773 51 common/cmd_ide.c reading Image from IDE device OK
1774 52 common/cmd_nand.c before loading a Image from a NAND device
1775 -53 common/cmd_nand.c Bad usage of "nand" command
1776 53 common/cmd_nand.c correct usage of "nand" command
1777 -54 common/cmd_nand.c No boot device
1778 54 common/cmd_nand.c boot device found
1779 -55 common/cmd_nand.c Unknown Chip ID on boot device
1780 55 common/cmd_nand.c correct chip ID found, device available
1781 -56 common/cmd_nand.c Error reading Image Header on boot device
1782 56 common/cmd_nand.c reading Image Header from NAND device OK
1783 -57 common/cmd_nand.c Image header has bad magic number
1784 57 common/cmd_nand.c Image header has correct magic number
1785 -58 common/cmd_nand.c Error reading Image from NAND device
1786 58 common/cmd_nand.c reading Image from NAND device OK
1788 -60 common/env_common.c Environment has a bad CRC, using default
1790 64 net/eth.c starting with Ethernetconfiguration.
1791 -64 net/eth.c no Ethernet found.
1792 65 net/eth.c Ethernet found.
1794 -80 common/cmd_net.c usage wrong
1795 80 common/cmd_net.c before calling NetLoop()
1796 -81 common/cmd_net.c some error in NetLoop() occured
1797 81 common/cmd_net.c NetLoop() back without error
1798 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1799 82 common/cmd_net.c trying automatic boot
1800 83 common/cmd_net.c running autoscript
1801 -83 common/cmd_net.c some error in automatic boot or autoscript
1802 84 common/cmd_net.c end without errors
1807 100 common/cmd_bootm.c Kernel FIT Image has correct format
1808 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1809 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1810 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1811 102 common/cmd_bootm.c Kernel unit name specified
1812 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1813 103 common/cmd_bootm.c Found configuration node
1814 104 common/cmd_bootm.c Got kernel subimage node offset
1815 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1816 105 common/cmd_bootm.c Kernel subimage hash verification OK
1817 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1818 106 common/cmd_bootm.c Architecture check OK
1819 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1820 107 common/cmd_bootm.c Kernel subimge type OK
1821 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1822 108 common/cmd_bootm.c Got kernel subimage data/size
1823 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1824 -109 common/cmd_bootm.c Can't get kernel subimage type
1825 -110 common/cmd_bootm.c Can't get kernel subimage comp
1826 -111 common/cmd_bootm.c Can't get kernel subimage os
1827 -112 common/cmd_bootm.c Can't get kernel subimage load address
1828 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1830 120 common/image.c Start initial ramdisk verification
1831 -120 common/image.c Ramdisk FIT image has incorrect format
1832 121 common/image.c Ramdisk FIT image has correct format
1833 122 common/image.c No Ramdisk subimage unit name, using configuration
1834 -122 common/image.c Can't get configuration for ramdisk subimage
1835 123 common/image.c Ramdisk unit name specified
1836 -124 common/image.c Can't get ramdisk subimage node offset
1837 125 common/image.c Got ramdisk subimage node offset
1838 -125 common/image.c Ramdisk subimage hash verification failed
1839 126 common/image.c Ramdisk subimage hash verification OK
1840 -126 common/image.c Ramdisk subimage for unsupported architecture
1841 127 common/image.c Architecture check OK
1842 -127 common/image.c Can't get ramdisk subimage data/size
1843 128 common/image.c Got ramdisk subimage data/size
1844 129 common/image.c Can't get ramdisk load address
1845 -129 common/image.c Got ramdisk load address
1847 -130 common/cmd_doc.c Icorrect FIT image format
1848 131 common/cmd_doc.c FIT image format OK
1850 -140 common/cmd_ide.c Icorrect FIT image format
1851 141 common/cmd_ide.c FIT image format OK
1853 -150 common/cmd_nand.c Icorrect FIT image format
1854 151 common/cmd_nand.c FIT image format OK
1860 [so far only for SMDK2400 and TRAB boards]
1862 - Modem support endable:
1863 CONFIG_MODEM_SUPPORT
1865 - RTS/CTS Flow control enable:
1868 - Modem debug support:
1869 CONFIG_MODEM_SUPPORT_DEBUG
1871 Enables debugging stuff (char screen[1024], dbg())
1872 for modem support. Useful only with BDI2000.
1874 - Interrupt support (PPC):
1876 There are common interrupt_init() and timer_interrupt()
1877 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1878 for cpu specific initialization. interrupt_init_cpu()
1879 should set decrementer_count to appropriate value. If
1880 cpu resets decrementer automatically after interrupt
1881 (ppc4xx) it should set decrementer_count to zero.
1882 timer_interrupt() calls timer_interrupt_cpu() for cpu
1883 specific handling. If board has watchdog / status_led
1884 / other_activity_monitor it works automatically from
1885 general timer_interrupt().
1889 In the target system modem support is enabled when a
1890 specific key (key combination) is pressed during
1891 power-on. Otherwise U-Boot will boot normally
1892 (autoboot). The key_pressed() fuction is called from
1893 board_init(). Currently key_pressed() is a dummy
1894 function, returning 1 and thus enabling modem
1897 If there are no modem init strings in the
1898 environment, U-Boot proceed to autoboot; the
1899 previous output (banner, info printfs) will be
1902 See also: doc/README.Modem
1905 Configuration Settings:
1906 -----------------------
1908 - CFG_LONGHELP: Defined when you want long help messages included;
1909 undefine this when you're short of memory.
1911 - CFG_PROMPT: This is what U-Boot prints on the console to
1912 prompt for user input.
1914 - CFG_CBSIZE: Buffer size for input from the Console
1916 - CFG_PBSIZE: Buffer size for Console output
1918 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1920 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1921 the application (usually a Linux kernel) when it is
1924 - CFG_BAUDRATE_TABLE:
1925 List of legal baudrate settings for this board.
1927 - CFG_CONSOLE_INFO_QUIET
1928 Suppress display of console information at boot.
1930 - CFG_CONSOLE_IS_IN_ENV
1931 If the board specific function
1932 extern int overwrite_console (void);
1933 returns 1, the stdin, stderr and stdout are switched to the
1934 serial port, else the settings in the environment are used.
1936 - CFG_CONSOLE_OVERWRITE_ROUTINE
1937 Enable the call to overwrite_console().
1939 - CFG_CONSOLE_ENV_OVERWRITE
1940 Enable overwrite of previous console environment settings.
1942 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1943 Begin and End addresses of the area used by the
1947 Enable an alternate, more extensive memory test.
1949 - CFG_MEMTEST_SCRATCH:
1950 Scratch address used by the alternate memory test
1951 You only need to set this if address zero isn't writeable
1953 - CFG_MEM_TOP_HIDE (PPC only):
1954 If CFG_MEM_TOP_HIDE is defined in the board config header,
1955 this specified memory area will get subtracted from the top
1956 (end) of ram and won't get "touched" at all by U-Boot. By
1957 fixing up gd->ram_size the Linux kernel should gets passed
1958 the now "corrected" memory size and won't touch it either.
1959 This should work for arch/ppc and arch/powerpc. Only Linux
1960 board ports in arch/powerpc with bootwrapper support that
1961 recalculate the memory size from the SDRAM controller setup
1962 will have to get fixed in Linux additionally.
1964 This option can be used as a workaround for the 440EPx/GRx
1965 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1968 WARNING: Please make sure that this value is a multiple of
1969 the Linux page size (normally 4k). If this is not the case,
1970 then the end address of the Linux memory will be located at a
1971 non page size aligned address and this could cause major
1974 - CFG_TFTP_LOADADDR:
1975 Default load address for network file downloads
1977 - CFG_LOADS_BAUD_CHANGE:
1978 Enable temporary baudrate change while serial download
1981 Physical start address of SDRAM. _Must_ be 0 here.
1984 Physical start address of Motherboard I/O (if using a
1988 Physical start address of Flash memory.
1991 Physical start address of boot monitor code (set by
1992 make config files to be same as the text base address
1993 (TEXT_BASE) used when linking) - same as
1994 CFG_FLASH_BASE when booting from flash.
1997 Size of memory reserved for monitor code, used to
1998 determine _at_compile_time_ (!) if the environment is
1999 embedded within the U-Boot image, or in a separate
2003 Size of DRAM reserved for malloc() use.
2006 Normally compressed uImages are limited to an
2007 uncompressed size of 8 MBytes. If this is not enough,
2008 you can define CFG_BOOTM_LEN in your board config file
2009 to adjust this setting to your needs.
2012 Maximum size of memory mapped by the startup code of
2013 the Linux kernel; all data that must be processed by
2014 the Linux kernel (bd_info, boot arguments, FDT blob if
2015 used) must be put below this limit, unless "bootm_low"
2016 enviroment variable is defined and non-zero. In such case
2017 all data for the Linux kernel must be between "bootm_low"
2018 and "bootm_low" + CFG_BOOTMAPSZ.
2020 - CFG_MAX_FLASH_BANKS:
2021 Max number of Flash memory banks
2023 - CFG_MAX_FLASH_SECT:
2024 Max number of sectors on a Flash chip
2026 - CFG_FLASH_ERASE_TOUT:
2027 Timeout for Flash erase operations (in ms)
2029 - CFG_FLASH_WRITE_TOUT:
2030 Timeout for Flash write operations (in ms)
2032 - CFG_FLASH_LOCK_TOUT
2033 Timeout for Flash set sector lock bit operation (in ms)
2035 - CFG_FLASH_UNLOCK_TOUT
2036 Timeout for Flash clear lock bits operation (in ms)
2038 - CFG_FLASH_PROTECTION
2039 If defined, hardware flash sectors protection is used
2040 instead of U-Boot software protection.
2042 - CFG_DIRECT_FLASH_TFTP:
2044 Enable TFTP transfers directly to flash memory;
2045 without this option such a download has to be
2046 performed in two steps: (1) download to RAM, and (2)
2047 copy from RAM to flash.
2049 The two-step approach is usually more reliable, since
2050 you can check if the download worked before you erase
2051 the flash, but in some situations (when sytem RAM is
2052 too limited to allow for a tempory copy of the
2053 downloaded image) this option may be very useful.
2056 Define if the flash driver uses extra elements in the
2057 common flash structure for storing flash geometry.
2059 - CFG_FLASH_CFI_DRIVER
2060 This option also enables the building of the cfi_flash driver
2061 in the drivers directory
2063 - CFG_FLASH_USE_BUFFER_WRITE
2064 Use buffered writes to flash.
2066 - CONFIG_FLASH_SPANSION_S29WS_N
2067 s29ws-n MirrorBit flash has non-standard addresses for buffered
2070 - CFG_FLASH_QUIET_TEST
2071 If this option is defined, the common CFI flash doesn't
2072 print it's warning upon not recognized FLASH banks. This
2073 is useful, if some of the configured banks are only
2074 optionally available.
2076 - CONFIG_FLASH_SHOW_PROGRESS
2077 If defined (must be an integer), print out countdown
2078 digits and dots. Recommended value: 45 (9..1) for 80
2079 column displays, 15 (3..1) for 40 column displays.
2081 - CFG_RX_ETH_BUFFER:
2082 Defines the number of ethernet receive buffers. On some
2083 ethernet controllers it is recommended to set this value
2084 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2085 buffers can be full shortly after enabling the interface
2086 on high ethernet traffic.
2087 Defaults to 4 if not defined.
2089 The following definitions that deal with the placement and management
2090 of environment data (variable area); in general, we support the
2091 following configurations:
2093 - CFG_ENV_IS_IN_FLASH:
2095 Define this if the environment is in flash memory.
2097 a) The environment occupies one whole flash sector, which is
2098 "embedded" in the text segment with the U-Boot code. This
2099 happens usually with "bottom boot sector" or "top boot
2100 sector" type flash chips, which have several smaller
2101 sectors at the start or the end. For instance, such a
2102 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2103 such a case you would place the environment in one of the
2104 4 kB sectors - with U-Boot code before and after it. With
2105 "top boot sector" type flash chips, you would put the
2106 environment in one of the last sectors, leaving a gap
2107 between U-Boot and the environment.
2111 Offset of environment data (variable area) to the
2112 beginning of flash memory; for instance, with bottom boot
2113 type flash chips the second sector can be used: the offset
2114 for this sector is given here.
2116 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2120 This is just another way to specify the start address of
2121 the flash sector containing the environment (instead of
2124 - CFG_ENV_SECT_SIZE:
2126 Size of the sector containing the environment.
2129 b) Sometimes flash chips have few, equal sized, BIG sectors.
2130 In such a case you don't want to spend a whole sector for
2135 If you use this in combination with CFG_ENV_IS_IN_FLASH
2136 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2137 of this flash sector for the environment. This saves
2138 memory for the RAM copy of the environment.
2140 It may also save flash memory if you decide to use this
2141 when your environment is "embedded" within U-Boot code,
2142 since then the remainder of the flash sector could be used
2143 for U-Boot code. It should be pointed out that this is
2144 STRONGLY DISCOURAGED from a robustness point of view:
2145 updating the environment in flash makes it always
2146 necessary to erase the WHOLE sector. If something goes
2147 wrong before the contents has been restored from a copy in
2148 RAM, your target system will be dead.
2150 - CFG_ENV_ADDR_REDUND
2153 These settings describe a second storage area used to hold
2154 a redundand copy of the environment data, so that there is
2155 a valid backup copy in case there is a power failure during
2156 a "saveenv" operation.
2158 BE CAREFUL! Any changes to the flash layout, and some changes to the
2159 source code will make it necessary to adapt <board>/u-boot.lds*
2163 - CFG_ENV_IS_IN_NVRAM:
2165 Define this if you have some non-volatile memory device
2166 (NVRAM, battery buffered SRAM) which you want to use for the
2172 These two #defines are used to determin the memory area you
2173 want to use for environment. It is assumed that this memory
2174 can just be read and written to, without any special
2177 BE CAREFUL! The first access to the environment happens quite early
2178 in U-Boot initalization (when we try to get the setting of for the
2179 console baudrate). You *MUST* have mappend your NVRAM area then, or
2182 Please note that even with NVRAM we still use a copy of the
2183 environment in RAM: we could work on NVRAM directly, but we want to
2184 keep settings there always unmodified except somebody uses "saveenv"
2185 to save the current settings.
2188 - CFG_ENV_IS_IN_EEPROM:
2190 Use this if you have an EEPROM or similar serial access
2191 device and a driver for it.
2196 These two #defines specify the offset and size of the
2197 environment area within the total memory of your EEPROM.
2199 - CFG_I2C_EEPROM_ADDR:
2200 If defined, specified the chip address of the EEPROM device.
2201 The default address is zero.
2203 - CFG_EEPROM_PAGE_WRITE_BITS:
2204 If defined, the number of bits used to address bytes in a
2205 single page in the EEPROM device. A 64 byte page, for example
2206 would require six bits.
2208 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2209 If defined, the number of milliseconds to delay between
2210 page writes. The default is zero milliseconds.
2212 - CFG_I2C_EEPROM_ADDR_LEN:
2213 The length in bytes of the EEPROM memory array address. Note
2214 that this is NOT the chip address length!
2216 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2217 EEPROM chips that implement "address overflow" are ones
2218 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2219 address and the extra bits end up in the "chip address" bit
2220 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2223 Note that we consider the length of the address field to
2224 still be one byte because the extra address bits are hidden
2225 in the chip address.
2228 The size in bytes of the EEPROM device.
2231 - CFG_ENV_IS_IN_DATAFLASH:
2233 Define this if you have a DataFlash memory device which you
2234 want to use for the environment.
2240 These three #defines specify the offset and size of the
2241 environment area within the total memory of your DataFlash placed
2242 at the specified address.
2244 - CFG_ENV_IS_IN_NAND:
2246 Define this if you have a NAND device which you want to use
2247 for the environment.
2252 These two #defines specify the offset and size of the environment
2253 area within the first NAND device.
2255 - CFG_ENV_OFFSET_REDUND
2257 This setting describes a second storage area of CFG_ENV_SIZE
2258 size used to hold a redundant copy of the environment data,
2259 so that there is a valid backup copy in case there is a
2260 power failure during a "saveenv" operation.
2262 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2263 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2264 the NAND devices block size.
2266 - CFG_SPI_INIT_OFFSET
2268 Defines offset to the initial SPI buffer area in DPRAM. The
2269 area is used at an early stage (ROM part) if the environment
2270 is configured to reside in the SPI EEPROM: We need a 520 byte
2271 scratch DPRAM area. It is used between the two initialization
2272 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2273 to be a good choice since it makes it far enough from the
2274 start of the data area as well as from the stack pointer.
2276 Please note that the environment is read-only until the monitor
2277 has been relocated to RAM and a RAM copy of the environment has been
2278 created; also, when using EEPROM you will have to use getenv_r()
2279 until then to read environment variables.
2281 The environment is protected by a CRC32 checksum. Before the monitor
2282 is relocated into RAM, as a result of a bad CRC you will be working
2283 with the compiled-in default environment - *silently*!!! [This is
2284 necessary, because the first environment variable we need is the
2285 "baudrate" setting for the console - if we have a bad CRC, we don't
2286 have any device yet where we could complain.]
2288 Note: once the monitor has been relocated, then it will complain if
2289 the default environment is used; a new CRC is computed as soon as you
2290 use the "saveenv" command to store a valid environment.
2292 - CFG_FAULT_ECHO_LINK_DOWN:
2293 Echo the inverted Ethernet link state to the fault LED.
2295 Note: If this option is active, then CFG_FAULT_MII_ADDR
2296 also needs to be defined.
2298 - CFG_FAULT_MII_ADDR:
2299 MII address of the PHY to check for the Ethernet link state.
2301 - CFG_64BIT_VSPRINTF:
2302 Makes vsprintf (and all *printf functions) support printing
2303 of 64bit values by using the L quantifier
2305 - CFG_64BIT_STRTOUL:
2306 Adds simple_strtoull that returns a 64bit value
2308 Low Level (hardware related) configuration options:
2309 ---------------------------------------------------
2311 - CFG_CACHELINE_SIZE:
2312 Cache Line Size of the CPU.
2315 Default address of the IMMR after system reset.
2317 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2318 and RPXsuper) to be able to adjust the position of
2319 the IMMR register after a reset.
2321 - Floppy Disk Support:
2322 CFG_FDC_DRIVE_NUMBER
2324 the default drive number (default value 0)
2328 defines the spacing between fdc chipset registers
2333 defines the offset of register from address. It
2334 depends on which part of the data bus is connected to
2335 the fdc chipset. (default value 0)
2337 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2338 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2341 if CFG_FDC_HW_INIT is defined, then the function
2342 fdc_hw_init() is called at the beginning of the FDC
2343 setup. fdc_hw_init() must be provided by the board
2344 source code. It is used to make hardware dependant
2347 - CFG_IMMR: Physical address of the Internal Memory.
2348 DO NOT CHANGE unless you know exactly what you're
2349 doing! (11-4) [MPC8xx/82xx systems only]
2351 - CFG_INIT_RAM_ADDR:
2353 Start address of memory area that can be used for
2354 initial data and stack; please note that this must be
2355 writable memory that is working WITHOUT special
2356 initialization, i. e. you CANNOT use normal RAM which
2357 will become available only after programming the
2358 memory controller and running certain initialization
2361 U-Boot uses the following memory types:
2362 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2363 - MPC824X: data cache
2364 - PPC4xx: data cache
2366 - CFG_GBL_DATA_OFFSET:
2368 Offset of the initial data structure in the memory
2369 area defined by CFG_INIT_RAM_ADDR. Usually
2370 CFG_GBL_DATA_OFFSET is chosen such that the initial
2371 data is located at the end of the available space
2372 (sometimes written as (CFG_INIT_RAM_END -
2373 CFG_INIT_DATA_SIZE), and the initial stack is just
2374 below that area (growing from (CFG_INIT_RAM_ADDR +
2375 CFG_GBL_DATA_OFFSET) downward.
2378 On the MPC824X (or other systems that use the data
2379 cache for initial memory) the address chosen for
2380 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2381 point to an otherwise UNUSED address space between
2382 the top of RAM and the start of the PCI space.
2384 - CFG_SIUMCR: SIU Module Configuration (11-6)
2386 - CFG_SYPCR: System Protection Control (11-9)
2388 - CFG_TBSCR: Time Base Status and Control (11-26)
2390 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2392 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2394 - CFG_SCCR: System Clock and reset Control Register (15-27)
2396 - CFG_OR_TIMING_SDRAM:
2400 periodic timer for refresh
2402 - CFG_DER: Debug Event Register (37-47)
2404 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2405 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2406 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2408 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2410 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2411 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2412 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2413 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2415 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2416 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2417 Machine Mode Register and Memory Periodic Timer
2418 Prescaler definitions (SDRAM timing)
2420 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2421 enable I2C microcode relocation patch (MPC8xx);
2422 define relocation offset in DPRAM [DSP2]
2424 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2425 enable SMC microcode relocation patch (MPC8xx);
2426 define relocation offset in DPRAM [SMC1]
2428 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2429 enable SPI microcode relocation patch (MPC8xx);
2430 define relocation offset in DPRAM [SCC4]
2433 Use OSCM clock mode on MBX8xx board. Be careful,
2434 wrong setting might damage your board. Read
2435 doc/README.MBX before setting this variable!
2437 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2438 Offset of the bootmode word in DPRAM used by post
2439 (Power On Self Tests). This definition overrides
2440 #define'd default value in commproc.h resp.
2443 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2444 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2445 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2446 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2447 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2448 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2449 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2450 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2451 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2454 Get DDR timing information from an I2C EEPROM. Common
2455 with pluggable memory modules such as SODIMMs
2458 I2C address of the SPD EEPROM
2461 If SPD EEPROM is on an I2C bus other than the first
2462 one, specify here. Note that the value must resolve
2463 to something your driver can deal with.
2465 - CFG_83XX_DDR_USES_CS0
2466 Only for 83xx systems. If specified, then DDR should
2467 be configured using CS0 and CS1 instead of CS2 and CS3.
2469 - CFG_83XX_DDR_USES_CS0
2470 Only for 83xx systems. If specified, then DDR should
2471 be configured using CS0 and CS1 instead of CS2 and CS3.
2473 - CONFIG_ETHER_ON_FEC[12]
2474 Define to enable FEC[12] on a 8xx series processor.
2476 - CONFIG_FEC[12]_PHY
2477 Define to the hardcoded PHY address which corresponds
2478 to the given FEC; i. e.
2479 #define CONFIG_FEC1_PHY 4
2480 means that the PHY with address 4 is connected to FEC1
2482 When set to -1, means to probe for first available.
2484 - CONFIG_FEC[12]_PHY_NORXERR
2485 The PHY does not have a RXERR line (RMII only).
2486 (so program the FEC to ignore it).
2489 Enable RMII mode for all FECs.
2490 Note that this is a global option, we can't
2491 have one FEC in standard MII mode and another in RMII mode.
2493 - CONFIG_CRC32_VERIFY
2494 Add a verify option to the crc32 command.
2497 => crc32 -v <address> <count> <crc32>
2499 Where address/count indicate a memory area
2500 and crc32 is the correct crc32 which the
2504 Add the "loopw" memory command. This only takes effect if
2505 the memory commands are activated globally (CONFIG_CMD_MEM).
2508 Add the "mdc" and "mwc" memory commands. These are cyclic
2513 This command will print 4 bytes (10,11,12,13) each 500 ms.
2515 => mwc.l 100 12345678 10
2516 This command will write 12345678 to address 100 all 10 ms.
2518 This only takes effect if the memory commands are activated
2519 globally (CONFIG_CMD_MEM).
2521 - CONFIG_SKIP_LOWLEVEL_INIT
2522 - CONFIG_SKIP_RELOCATE_UBOOT
2524 [ARM only] If these variables are defined, then
2525 certain low level initializations (like setting up
2526 the memory controller) are omitted and/or U-Boot does
2527 not relocate itself into RAM.
2528 Normally these variables MUST NOT be defined. The
2529 only exception is when U-Boot is loaded (to RAM) by
2530 some other boot loader or by a debugger which
2531 performs these intializations itself.
2534 Building the Software:
2535 ======================
2537 Building U-Boot has been tested in several native build environments
2538 and in many different cross environments. Of course we cannot support
2539 all possibly existing versions of cross development tools in all
2540 (potentially obsolete) versions. In case of tool chain problems we
2541 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2542 which is extensively used to build and test U-Boot.
2544 If you are not using a native environment, it is assumed that you
2545 have GNU cross compiling tools available in your path. In this case,
2546 you must set the environment variable CROSS_COMPILE in your shell.
2547 Note that no changes to the Makefile or any other source files are
2548 necessary. For example using the ELDK on a 4xx CPU, please enter:
2550 $ CROSS_COMPILE=ppc_4xx-
2551 $ export CROSS_COMPILE
2553 U-Boot is intended to be simple to build. After installing the
2554 sources you must configure U-Boot for one specific board type. This
2559 where "NAME_config" is the name of one of the existing configu-
2560 rations; see the main Makefile for supported names.
2562 Note: for some board special configuration names may exist; check if
2563 additional information is available from the board vendor; for
2564 instance, the TQM823L systems are available without (standard)
2565 or with LCD support. You can select such additional "features"
2566 when chosing the configuration, i. e.
2569 - will configure for a plain TQM823L, i. e. no LCD support
2571 make TQM823L_LCD_config
2572 - will configure for a TQM823L with U-Boot console on LCD
2577 Finally, type "make all", and you should get some working U-Boot
2578 images ready for download to / installation on your system:
2580 - "u-boot.bin" is a raw binary image
2581 - "u-boot" is an image in ELF binary format
2582 - "u-boot.srec" is in Motorola S-Record format
2584 By default the build is performed locally and the objects are saved
2585 in the source directory. One of the two methods can be used to change
2586 this behavior and build U-Boot to some external directory:
2588 1. Add O= to the make command line invocations:
2590 make O=/tmp/build distclean
2591 make O=/tmp/build NAME_config
2592 make O=/tmp/build all
2594 2. Set environment variable BUILD_DIR to point to the desired location:
2596 export BUILD_DIR=/tmp/build
2601 Note that the command line "O=" setting overrides the BUILD_DIR environment
2605 Please be aware that the Makefiles assume you are using GNU make, so
2606 for instance on NetBSD you might need to use "gmake" instead of
2610 If the system board that you have is not listed, then you will need
2611 to port U-Boot to your hardware platform. To do this, follow these
2614 1. Add a new configuration option for your board to the toplevel
2615 "Makefile" and to the "MAKEALL" script, using the existing
2616 entries as examples. Note that here and at many other places
2617 boards and other names are listed in alphabetical sort order. Please
2619 2. Create a new directory to hold your board specific code. Add any
2620 files you need. In your board directory, you will need at least
2621 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2622 3. Create a new configuration file "include/configs/<board>.h" for
2624 3. If you're porting U-Boot to a new CPU, then also create a new
2625 directory to hold your CPU specific code. Add any files you need.
2626 4. Run "make <board>_config" with your new name.
2627 5. Type "make", and you should get a working "u-boot.srec" file
2628 to be installed on your target system.
2629 6. Debug and solve any problems that might arise.
2630 [Of course, this last step is much harder than it sounds.]
2633 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2634 ==============================================================
2636 If you have modified U-Boot sources (for instance added a new board
2637 or support for new devices, a new CPU, etc.) you are expected to
2638 provide feedback to the other developers. The feedback normally takes
2639 the form of a "patch", i. e. a context diff against a certain (latest
2640 official or latest in the git repository) version of U-Boot sources.
2642 But before you submit such a patch, please verify that your modifi-
2643 cation did not break existing code. At least make sure that *ALL* of
2644 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2645 just run the "MAKEALL" script, which will configure and build U-Boot
2646 for ALL supported system. Be warned, this will take a while. You can
2647 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2648 environment variable to the script, i. e. to use the ELDK cross tools
2651 CROSS_COMPILE=ppc_8xx- MAKEALL
2653 or to build on a native PowerPC system you can type
2655 CROSS_COMPILE=' ' MAKEALL
2657 When using the MAKEALL script, the default behaviour is to build
2658 U-Boot in the source directory. This location can be changed by
2659 setting the BUILD_DIR environment variable. Also, for each target
2660 built, the MAKEALL script saves two log files (<target>.ERR and
2661 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2662 location can be changed by setting the MAKEALL_LOGDIR environment
2663 variable. For example:
2665 export BUILD_DIR=/tmp/build
2666 export MAKEALL_LOGDIR=/tmp/log
2667 CROSS_COMPILE=ppc_8xx- MAKEALL
2669 With the above settings build objects are saved in the /tmp/build,
2670 log files are saved in the /tmp/log and the source tree remains clean
2671 during the whole build process.
2674 See also "U-Boot Porting Guide" below.
2677 Monitor Commands - Overview:
2678 ============================
2680 go - start application at address 'addr'
2681 run - run commands in an environment variable
2682 bootm - boot application image from memory
2683 bootp - boot image via network using BootP/TFTP protocol
2684 tftpboot- boot image via network using TFTP protocol
2685 and env variables "ipaddr" and "serverip"
2686 (and eventually "gatewayip")
2687 rarpboot- boot image via network using RARP/TFTP protocol
2688 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2689 loads - load S-Record file over serial line
2690 loadb - load binary file over serial line (kermit mode)
2692 mm - memory modify (auto-incrementing)
2693 nm - memory modify (constant address)
2694 mw - memory write (fill)
2696 cmp - memory compare
2697 crc32 - checksum calculation
2698 imd - i2c memory display
2699 imm - i2c memory modify (auto-incrementing)
2700 inm - i2c memory modify (constant address)
2701 imw - i2c memory write (fill)
2702 icrc32 - i2c checksum calculation
2703 iprobe - probe to discover valid I2C chip addresses
2704 iloop - infinite loop on address range
2705 isdram - print SDRAM configuration information
2706 sspi - SPI utility commands
2707 base - print or set address offset
2708 printenv- print environment variables
2709 setenv - set environment variables
2710 saveenv - save environment variables to persistent storage
2711 protect - enable or disable FLASH write protection
2712 erase - erase FLASH memory
2713 flinfo - print FLASH memory information
2714 bdinfo - print Board Info structure
2715 iminfo - print header information for application image
2716 coninfo - print console devices and informations
2717 ide - IDE sub-system
2718 loop - infinite loop on address range
2719 loopw - infinite write loop on address range
2720 mtest - simple RAM test
2721 icache - enable or disable instruction cache
2722 dcache - enable or disable data cache
2723 reset - Perform RESET of the CPU
2724 echo - echo args to console
2725 version - print monitor version
2726 help - print online help
2727 ? - alias for 'help'
2730 Monitor Commands - Detailed Description:
2731 ========================================
2735 For now: just type "help <command>".
2738 Environment Variables:
2739 ======================
2741 U-Boot supports user configuration using Environment Variables which
2742 can be made persistent by saving to Flash memory.
2744 Environment Variables are set using "setenv", printed using
2745 "printenv", and saved to Flash using "saveenv". Using "setenv"
2746 without a value can be used to delete a variable from the
2747 environment. As long as you don't save the environment you are
2748 working with an in-memory copy. In case the Flash area containing the
2749 environment is erased by accident, a default environment is provided.
2751 Some configuration options can be set using Environment Variables:
2753 baudrate - see CONFIG_BAUDRATE
2755 bootdelay - see CONFIG_BOOTDELAY
2757 bootcmd - see CONFIG_BOOTCOMMAND
2759 bootargs - Boot arguments when booting an RTOS image
2761 bootfile - Name of the image to load with TFTP
2763 bootm_low - Memory range available for image processing in the bootm
2764 command can be restricted. This variable is given as
2765 a hexadecimal number and defines lowest address allowed
2766 for use by the bootm command. See also "bootm_size"
2767 environment variable. Address defined by "bootm_low" is
2768 also the base of the initial memory mapping for the Linux
2769 kernel -- see the descripton of CFG_BOOTMAPSZ.
2771 bootm_size - Memory range available for image processing in the bootm
2772 command can be restricted. This variable is given as
2773 a hexadecimal number and defines the size of the region
2774 allowed for use by the bootm command. See also "bootm_low"
2775 environment variable.
2777 autoload - if set to "no" (any string beginning with 'n'),
2778 "bootp" will just load perform a lookup of the
2779 configuration from the BOOTP server, but not try to
2780 load any image using TFTP
2782 autoscript - if set to "yes" commands like "loadb", "loady",
2783 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2784 to automatically run script images (by internally
2785 calling "autoscript").
2787 autoscript_uname - if script image is in a format (FIT) this
2788 variable is used to get script subimage unit name.
2790 autostart - if set to "yes", an image loaded using the "bootp",
2791 "rarpboot", "tftpboot" or "diskboot" commands will
2792 be automatically started (by internally calling
2795 If set to "no", a standalone image passed to the
2796 "bootm" command will be copied to the load address
2797 (and eventually uncompressed), but NOT be started.
2798 This can be used to load and uncompress arbitrary
2801 i2cfast - (PPC405GP|PPC405EP only)
2802 if set to 'y' configures Linux I2C driver for fast
2803 mode (400kHZ). This environment variable is used in
2804 initialization code. So, for changes to be effective
2805 it must be saved and board must be reset.
2807 initrd_high - restrict positioning of initrd images:
2808 If this variable is not set, initrd images will be
2809 copied to the highest possible address in RAM; this
2810 is usually what you want since it allows for
2811 maximum initrd size. If for some reason you want to
2812 make sure that the initrd image is loaded below the
2813 CFG_BOOTMAPSZ limit, you can set this environment
2814 variable to a value of "no" or "off" or "0".
2815 Alternatively, you can set it to a maximum upper
2816 address to use (U-Boot will still check that it
2817 does not overwrite the U-Boot stack and data).
2819 For instance, when you have a system with 16 MB
2820 RAM, and want to reserve 4 MB from use by Linux,
2821 you can do this by adding "mem=12M" to the value of
2822 the "bootargs" variable. However, now you must make
2823 sure that the initrd image is placed in the first
2824 12 MB as well - this can be done with
2826 setenv initrd_high 00c00000
2828 If you set initrd_high to 0xFFFFFFFF, this is an
2829 indication to U-Boot that all addresses are legal
2830 for the Linux kernel, including addresses in flash
2831 memory. In this case U-Boot will NOT COPY the
2832 ramdisk at all. This may be useful to reduce the
2833 boot time on your system, but requires that this
2834 feature is supported by your Linux kernel.
2836 ipaddr - IP address; needed for tftpboot command
2838 loadaddr - Default load address for commands like "bootp",
2839 "rarpboot", "tftpboot", "loadb" or "diskboot"
2841 loads_echo - see CONFIG_LOADS_ECHO
2843 serverip - TFTP server IP address; needed for tftpboot command
2845 bootretry - see CONFIG_BOOT_RETRY_TIME
2847 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2849 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2851 ethprime - When CONFIG_NET_MULTI is enabled controls which
2852 interface is used first.
2854 ethact - When CONFIG_NET_MULTI is enabled controls which
2855 interface is currently active. For example you
2856 can do the following
2858 => setenv ethact FEC ETHERNET
2859 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2860 => setenv ethact SCC ETHERNET
2861 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2863 ethrotate - When set to "no" U-Boot does not go through all
2864 available network interfaces.
2865 It just stays at the currently selected interface.
2867 netretry - When set to "no" each network operation will
2868 either succeed or fail without retrying.
2869 When set to "once" the network operation will
2870 fail when all the available network interfaces
2871 are tried once without success.
2872 Useful on scripts which control the retry operation
2875 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2876 if set load address for the npe microcode
2878 tftpsrcport - If this is set, the value is used for TFTP's
2881 tftpdstport - If this is set, the value is used for TFTP's UDP
2882 destination port instead of the Well Know Port 69.
2884 vlan - When set to a value < 4095 the traffic over
2885 ethernet is encapsulated/received over 802.1q
2888 The following environment variables may be used and automatically
2889 updated by the network boot commands ("bootp" and "rarpboot"),
2890 depending the information provided by your boot server:
2892 bootfile - see above
2893 dnsip - IP address of your Domain Name Server
2894 dnsip2 - IP address of your secondary Domain Name Server
2895 gatewayip - IP address of the Gateway (Router) to use
2896 hostname - Target hostname
2898 netmask - Subnet Mask
2899 rootpath - Pathname of the root filesystem on the NFS server
2900 serverip - see above
2903 There are two special Environment Variables:
2905 serial# - contains hardware identification information such
2906 as type string and/or serial number
2907 ethaddr - Ethernet address
2909 These variables can be set only once (usually during manufacturing of
2910 the board). U-Boot refuses to delete or overwrite these variables
2911 once they have been set once.
2914 Further special Environment Variables:
2916 ver - Contains the U-Boot version string as printed
2917 with the "version" command. This variable is
2918 readonly (see CONFIG_VERSION_VARIABLE).
2921 Please note that changes to some configuration parameters may take
2922 only effect after the next boot (yes, that's just like Windoze :-).
2925 Command Line Parsing:
2926 =====================
2928 There are two different command line parsers available with U-Boot:
2929 the old "simple" one, and the much more powerful "hush" shell:
2931 Old, simple command line parser:
2932 --------------------------------
2934 - supports environment variables (through setenv / saveenv commands)
2935 - several commands on one line, separated by ';'
2936 - variable substitution using "... ${name} ..." syntax
2937 - special characters ('$', ';') can be escaped by prefixing with '\',
2939 setenv bootcmd bootm \${address}
2940 - You can also escape text by enclosing in single apostrophes, for example:
2941 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2946 - similar to Bourne shell, with control structures like
2947 if...then...else...fi, for...do...done; while...do...done,
2948 until...do...done, ...
2949 - supports environment ("global") variables (through setenv / saveenv
2950 commands) and local shell variables (through standard shell syntax
2951 "name=value"); only environment variables can be used with "run"
2957 (1) If a command line (or an environment variable executed by a "run"
2958 command) contains several commands separated by semicolon, and
2959 one of these commands fails, then the remaining commands will be
2962 (2) If you execute several variables with one call to run (i. e.
2963 calling run with a list af variables as arguments), any failing
2964 command will cause "run" to terminate, i. e. the remaining
2965 variables are not executed.
2967 Note for Redundant Ethernet Interfaces:
2968 =======================================
2970 Some boards come with redundant ethernet interfaces; U-Boot supports
2971 such configurations and is capable of automatic selection of a
2972 "working" interface when needed. MAC assignment works as follows:
2974 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2975 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2976 "eth1addr" (=>eth1), "eth2addr", ...
2978 If the network interface stores some valid MAC address (for instance
2979 in SROM), this is used as default address if there is NO correspon-
2980 ding setting in the environment; if the corresponding environment
2981 variable is set, this overrides the settings in the card; that means:
2983 o If the SROM has a valid MAC address, and there is no address in the
2984 environment, the SROM's address is used.
2986 o If there is no valid address in the SROM, and a definition in the
2987 environment exists, then the value from the environment variable is
2990 o If both the SROM and the environment contain a MAC address, and
2991 both addresses are the same, this MAC address is used.
2993 o If both the SROM and the environment contain a MAC address, and the
2994 addresses differ, the value from the environment is used and a
2997 o If neither SROM nor the environment contain a MAC address, an error
3004 U-Boot is capable of booting (and performing other auxiliary operations on)
3005 images in two formats:
3007 New uImage format (FIT)
3008 -----------------------
3010 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3011 to Flattened Device Tree). It allows the use of images with multiple
3012 components (several kernels, ramdisks, etc.), with contents protected by
3013 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3019 Old image format is based on binary files which can be basically anything,
3020 preceded by a special header; see the definitions in include/image.h for
3021 details; basically, the header defines the following image properties:
3023 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3024 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3025 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3026 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3027 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3028 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3029 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3030 * Compression Type (uncompressed, gzip, bzip2)
3036 The header is marked by a special Magic Number, and both the header
3037 and the data portions of the image are secured against corruption by
3044 Although U-Boot should support any OS or standalone application
3045 easily, the main focus has always been on Linux during the design of
3048 U-Boot includes many features that so far have been part of some
3049 special "boot loader" code within the Linux kernel. Also, any
3050 "initrd" images to be used are no longer part of one big Linux image;
3051 instead, kernel and "initrd" are separate images. This implementation
3052 serves several purposes:
3054 - the same features can be used for other OS or standalone
3055 applications (for instance: using compressed images to reduce the
3056 Flash memory footprint)
3058 - it becomes much easier to port new Linux kernel versions because
3059 lots of low-level, hardware dependent stuff are done by U-Boot
3061 - the same Linux kernel image can now be used with different "initrd"
3062 images; of course this also means that different kernel images can
3063 be run with the same "initrd". This makes testing easier (you don't
3064 have to build a new "zImage.initrd" Linux image when you just
3065 change a file in your "initrd"). Also, a field-upgrade of the
3066 software is easier now.
3072 Porting Linux to U-Boot based systems:
3073 ---------------------------------------
3075 U-Boot cannot save you from doing all the necessary modifications to
3076 configure the Linux device drivers for use with your target hardware
3077 (no, we don't intend to provide a full virtual machine interface to
3080 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3082 Just make sure your machine specific header file (for instance
3083 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3084 Information structure as we define in include/u-boot.h, and make
3085 sure that your definition of IMAP_ADDR uses the same value as your
3086 U-Boot configuration in CFG_IMMR.
3089 Configuring the Linux kernel:
3090 -----------------------------
3092 No specific requirements for U-Boot. Make sure you have some root
3093 device (initial ramdisk, NFS) for your target system.
3096 Building a Linux Image:
3097 -----------------------
3099 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3100 not used. If you use recent kernel source, a new build target
3101 "uImage" will exist which automatically builds an image usable by
3102 U-Boot. Most older kernels also have support for a "pImage" target,
3103 which was introduced for our predecessor project PPCBoot and uses a
3104 100% compatible format.
3113 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3114 encapsulate a compressed Linux kernel image with header information,
3115 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3117 * build a standard "vmlinux" kernel image (in ELF binary format):
3119 * convert the kernel into a raw binary image:
3121 ${CROSS_COMPILE}-objcopy -O binary \
3122 -R .note -R .comment \
3123 -S vmlinux linux.bin
3125 * compress the binary image:
3129 * package compressed binary image for U-Boot:
3131 mkimage -A ppc -O linux -T kernel -C gzip \
3132 -a 0 -e 0 -n "Linux Kernel Image" \
3133 -d linux.bin.gz uImage
3136 The "mkimage" tool can also be used to create ramdisk images for use
3137 with U-Boot, either separated from the Linux kernel image, or
3138 combined into one file. "mkimage" encapsulates the images with a 64
3139 byte header containing information about target architecture,
3140 operating system, image type, compression method, entry points, time
3141 stamp, CRC32 checksums, etc.
3143 "mkimage" can be called in two ways: to verify existing images and
3144 print the header information, or to build new images.
3146 In the first form (with "-l" option) mkimage lists the information
3147 contained in the header of an existing U-Boot image; this includes
3148 checksum verification:
3150 tools/mkimage -l image
3151 -l ==> list image header information
3153 The second form (with "-d" option) is used to build a U-Boot image
3154 from a "data file" which is used as image payload:
3156 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3157 -n name -d data_file image
3158 -A ==> set architecture to 'arch'
3159 -O ==> set operating system to 'os'
3160 -T ==> set image type to 'type'
3161 -C ==> set compression type 'comp'
3162 -a ==> set load address to 'addr' (hex)
3163 -e ==> set entry point to 'ep' (hex)
3164 -n ==> set image name to 'name'
3165 -d ==> use image data from 'datafile'
3167 Right now, all Linux kernels for PowerPC systems use the same load
3168 address (0x00000000), but the entry point address depends on the
3171 - 2.2.x kernels have the entry point at 0x0000000C,
3172 - 2.3.x and later kernels have the entry point at 0x00000000.
3174 So a typical call to build a U-Boot image would read:
3176 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3177 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3178 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3179 > examples/uImage.TQM850L
3180 Image Name: 2.4.4 kernel for TQM850L
3181 Created: Wed Jul 19 02:34:59 2000
3182 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3183 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3184 Load Address: 0x00000000
3185 Entry Point: 0x00000000
3187 To verify the contents of the image (or check for corruption):
3189 -> tools/mkimage -l examples/uImage.TQM850L
3190 Image Name: 2.4.4 kernel for TQM850L
3191 Created: Wed Jul 19 02:34:59 2000
3192 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3193 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3194 Load Address: 0x00000000
3195 Entry Point: 0x00000000
3197 NOTE: for embedded systems where boot time is critical you can trade
3198 speed for memory and install an UNCOMPRESSED image instead: this
3199 needs more space in Flash, but boots much faster since it does not
3200 need to be uncompressed:
3202 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3203 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3204 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3205 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3206 > examples/uImage.TQM850L-uncompressed
3207 Image Name: 2.4.4 kernel for TQM850L
3208 Created: Wed Jul 19 02:34:59 2000
3209 Image Type: PowerPC Linux Kernel Image (uncompressed)
3210 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3211 Load Address: 0x00000000
3212 Entry Point: 0x00000000
3215 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3216 when your kernel is intended to use an initial ramdisk:
3218 -> tools/mkimage -n 'Simple Ramdisk Image' \
3219 > -A ppc -O linux -T ramdisk -C gzip \
3220 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3221 Image Name: Simple Ramdisk Image
3222 Created: Wed Jan 12 14:01:50 2000
3223 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3224 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3225 Load Address: 0x00000000
3226 Entry Point: 0x00000000
3229 Installing a Linux Image:
3230 -------------------------
3232 To downloading a U-Boot image over the serial (console) interface,
3233 you must convert the image to S-Record format:
3235 objcopy -I binary -O srec examples/image examples/image.srec
3237 The 'objcopy' does not understand the information in the U-Boot
3238 image header, so the resulting S-Record file will be relative to
3239 address 0x00000000. To load it to a given address, you need to
3240 specify the target address as 'offset' parameter with the 'loads'
3243 Example: install the image to address 0x40100000 (which on the
3244 TQM8xxL is in the first Flash bank):
3246 => erase 40100000 401FFFFF
3252 ## Ready for S-Record download ...
3253 ~>examples/image.srec
3254 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3256 15989 15990 15991 15992
3257 [file transfer complete]
3259 ## Start Addr = 0x00000000
3262 You can check the success of the download using the 'iminfo' command;
3263 this includes a checksum verification so you can be sure no data
3264 corruption happened:
3268 ## Checking Image at 40100000 ...
3269 Image Name: 2.2.13 for initrd on TQM850L
3270 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3271 Data Size: 335725 Bytes = 327 kB = 0 MB
3272 Load Address: 00000000
3273 Entry Point: 0000000c
3274 Verifying Checksum ... OK
3280 The "bootm" command is used to boot an application that is stored in
3281 memory (RAM or Flash). In case of a Linux kernel image, the contents
3282 of the "bootargs" environment variable is passed to the kernel as
3283 parameters. You can check and modify this variable using the
3284 "printenv" and "setenv" commands:
3287 => printenv bootargs
3288 bootargs=root=/dev/ram
3290 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3292 => printenv bootargs
3293 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3296 ## Booting Linux kernel at 40020000 ...
3297 Image Name: 2.2.13 for NFS on TQM850L
3298 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3299 Data Size: 381681 Bytes = 372 kB = 0 MB
3300 Load Address: 00000000
3301 Entry Point: 0000000c
3302 Verifying Checksum ... OK
3303 Uncompressing Kernel Image ... OK
3304 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
3305 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3306 time_init: decrementer frequency = 187500000/60
3307 Calibrating delay loop... 49.77 BogoMIPS
3308 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3311 If you want to boot a Linux kernel with initial ram disk, you pass
3312 the memory addresses of both the kernel and the initrd image (PPBCOOT
3313 format!) to the "bootm" command:
3315 => imi 40100000 40200000
3317 ## Checking Image at 40100000 ...
3318 Image Name: 2.2.13 for initrd on TQM850L
3319 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3320 Data Size: 335725 Bytes = 327 kB = 0 MB
3321 Load Address: 00000000
3322 Entry Point: 0000000c
3323 Verifying Checksum ... OK
3325 ## Checking Image at 40200000 ...
3326 Image Name: Simple Ramdisk Image
3327 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3328 Data Size: 566530 Bytes = 553 kB = 0 MB
3329 Load Address: 00000000
3330 Entry Point: 00000000
3331 Verifying Checksum ... OK
3333 => bootm 40100000 40200000
3334 ## Booting Linux kernel at 40100000 ...
3335 Image Name: 2.2.13 for initrd on TQM850L
3336 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3337 Data Size: 335725 Bytes = 327 kB = 0 MB
3338 Load Address: 00000000
3339 Entry Point: 0000000c
3340 Verifying Checksum ... OK
3341 Uncompressing Kernel Image ... OK
3342 ## Loading RAMDisk Image at 40200000 ...
3343 Image Name: Simple Ramdisk Image
3344 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3345 Data Size: 566530 Bytes = 553 kB = 0 MB
3346 Load Address: 00000000
3347 Entry Point: 00000000
3348 Verifying Checksum ... OK
3349 Loading Ramdisk ... OK
3350 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
3351 Boot arguments: root=/dev/ram
3352 time_init: decrementer frequency = 187500000/60
3353 Calibrating delay loop... 49.77 BogoMIPS
3355 RAMDISK: Compressed image found at block 0
3356 VFS: Mounted root (ext2 filesystem).
3360 Boot Linux and pass a flat device tree:
3363 First, U-Boot must be compiled with the appropriate defines. See the section
3364 titled "Linux Kernel Interface" above for a more in depth explanation. The
3365 following is an example of how to start a kernel and pass an updated
3371 oft=oftrees/mpc8540ads.dtb
3372 => tftp $oftaddr $oft
3373 Speed: 1000, full duplex
3375 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3376 Filename 'oftrees/mpc8540ads.dtb'.
3377 Load address: 0x300000
3380 Bytes transferred = 4106 (100a hex)
3381 => tftp $loadaddr $bootfile
3382 Speed: 1000, full duplex
3384 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3386 Load address: 0x200000
3387 Loading:############
3389 Bytes transferred = 1029407 (fb51f hex)
3394 => bootm $loadaddr - $oftaddr
3395 ## Booting image at 00200000 ...
3396 Image Name: Linux-2.6.17-dirty
3397 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3398 Data Size: 1029343 Bytes = 1005.2 kB
3399 Load Address: 00000000
3400 Entry Point: 00000000
3401 Verifying Checksum ... OK
3402 Uncompressing Kernel Image ... OK
3403 Booting using flat device tree at 0x300000
3404 Using MPC85xx ADS machine description
3405 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3409 More About U-Boot Image Types:
3410 ------------------------------
3412 U-Boot supports the following image types:
3414 "Standalone Programs" are directly runnable in the environment
3415 provided by U-Boot; it is expected that (if they behave
3416 well) you can continue to work in U-Boot after return from
3417 the Standalone Program.
3418 "OS Kernel Images" are usually images of some Embedded OS which
3419 will take over control completely. Usually these programs
3420 will install their own set of exception handlers, device
3421 drivers, set up the MMU, etc. - this means, that you cannot
3422 expect to re-enter U-Boot except by resetting the CPU.
3423 "RAMDisk Images" are more or less just data blocks, and their
3424 parameters (address, size) are passed to an OS kernel that is
3426 "Multi-File Images" contain several images, typically an OS
3427 (Linux) kernel image and one or more data images like
3428 RAMDisks. This construct is useful for instance when you want
3429 to boot over the network using BOOTP etc., where the boot
3430 server provides just a single image file, but you want to get
3431 for instance an OS kernel and a RAMDisk image.
3433 "Multi-File Images" start with a list of image sizes, each
3434 image size (in bytes) specified by an "uint32_t" in network
3435 byte order. This list is terminated by an "(uint32_t)0".
3436 Immediately after the terminating 0 follow the images, one by
3437 one, all aligned on "uint32_t" boundaries (size rounded up to
3438 a multiple of 4 bytes).
3440 "Firmware Images" are binary images containing firmware (like
3441 U-Boot or FPGA images) which usually will be programmed to
3444 "Script files" are command sequences that will be executed by
3445 U-Boot's command interpreter; this feature is especially
3446 useful when you configure U-Boot to use a real shell (hush)
3447 as command interpreter.
3453 One of the features of U-Boot is that you can dynamically load and
3454 run "standalone" applications, which can use some resources of
3455 U-Boot like console I/O functions or interrupt services.
3457 Two simple examples are included with the sources:
3462 'examples/hello_world.c' contains a small "Hello World" Demo
3463 application; it is automatically compiled when you build U-Boot.
3464 It's configured to run at address 0x00040004, so you can play with it
3468 ## Ready for S-Record download ...
3469 ~>examples/hello_world.srec
3470 1 2 3 4 5 6 7 8 9 10 11 ...
3471 [file transfer complete]
3473 ## Start Addr = 0x00040004
3475 => go 40004 Hello World! This is a test.
3476 ## Starting application at 0x00040004 ...
3487 Hit any key to exit ...
3489 ## Application terminated, rc = 0x0
3491 Another example, which demonstrates how to register a CPM interrupt
3492 handler with the U-Boot code, can be found in 'examples/timer.c'.
3493 Here, a CPM timer is set up to generate an interrupt every second.
3494 The interrupt service routine is trivial, just printing a '.'
3495 character, but this is just a demo program. The application can be
3496 controlled by the following keys:
3498 ? - print current values og the CPM Timer registers
3499 b - enable interrupts and start timer
3500 e - stop timer and disable interrupts
3501 q - quit application
3504 ## Ready for S-Record download ...
3505 ~>examples/timer.srec
3506 1 2 3 4 5 6 7 8 9 10 11 ...
3507 [file transfer complete]
3509 ## Start Addr = 0x00040004
3512 ## Starting application at 0x00040004 ...
3515 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3518 [q, b, e, ?] Set interval 1000000 us
3521 [q, b, e, ?] ........
3522 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3525 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3528 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3531 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3533 [q, b, e, ?] ...Stopping timer
3535 [q, b, e, ?] ## Application terminated, rc = 0x0
3541 Over time, many people have reported problems when trying to use the
3542 "minicom" terminal emulation program for serial download. I (wd)
3543 consider minicom to be broken, and recommend not to use it. Under
3544 Unix, I recommend to use C-Kermit for general purpose use (and
3545 especially for kermit binary protocol download ("loadb" command), and
3546 use "cu" for S-Record download ("loads" command).
3548 Nevertheless, if you absolutely want to use it try adding this
3549 configuration to your "File transfer protocols" section:
3551 Name Program Name U/D FullScr IO-Red. Multi
3552 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3553 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3559 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3560 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3562 Building requires a cross environment; it is known to work on
3563 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3564 need gmake since the Makefiles are not compatible with BSD make).
3565 Note that the cross-powerpc package does not install include files;
3566 attempting to build U-Boot will fail because <machine/ansi.h> is
3567 missing. This file has to be installed and patched manually:
3569 # cd /usr/pkg/cross/powerpc-netbsd/include
3571 # ln -s powerpc machine
3572 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3573 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3575 Native builds *don't* work due to incompatibilities between native
3576 and U-Boot include files.
3578 Booting assumes that (the first part of) the image booted is a
3579 stage-2 loader which in turn loads and then invokes the kernel
3580 proper. Loader sources will eventually appear in the NetBSD source
3581 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3582 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3585 Implementation Internals:
3586 =========================
3588 The following is not intended to be a complete description of every
3589 implementation detail. However, it should help to understand the
3590 inner workings of U-Boot and make it easier to port it to custom
3594 Initial Stack, Global Data:
3595 ---------------------------
3597 The implementation of U-Boot is complicated by the fact that U-Boot
3598 starts running out of ROM (flash memory), usually without access to
3599 system RAM (because the memory controller is not initialized yet).
3600 This means that we don't have writable Data or BSS segments, and BSS
3601 is not initialized as zero. To be able to get a C environment working
3602 at all, we have to allocate at least a minimal stack. Implementation
3603 options for this are defined and restricted by the CPU used: Some CPU
3604 models provide on-chip memory (like the IMMR area on MPC8xx and
3605 MPC826x processors), on others (parts of) the data cache can be
3606 locked as (mis-) used as memory, etc.
3608 Chris Hallinan posted a good summary of these issues to the
3609 u-boot-users mailing list:
3611 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3612 From: "Chris Hallinan" <clh@net1plus.com>
3613 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3616 Correct me if I'm wrong, folks, but the way I understand it
3617 is this: Using DCACHE as initial RAM for Stack, etc, does not
3618 require any physical RAM backing up the cache. The cleverness
3619 is that the cache is being used as a temporary supply of
3620 necessary storage before the SDRAM controller is setup. It's
3621 beyond the scope of this list to expain the details, but you
3622 can see how this works by studying the cache architecture and
3623 operation in the architecture and processor-specific manuals.
3625 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3626 is another option for the system designer to use as an
3627 initial stack/ram area prior to SDRAM being available. Either
3628 option should work for you. Using CS 4 should be fine if your
3629 board designers haven't used it for something that would
3630 cause you grief during the initial boot! It is frequently not
3633 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3634 with your processor/board/system design. The default value
3635 you will find in any recent u-boot distribution in
3636 walnut.h should work for you. I'd set it to a value larger
3637 than your SDRAM module. If you have a 64MB SDRAM module, set
3638 it above 400_0000. Just make sure your board has no resources
3639 that are supposed to respond to that address! That code in
3640 start.S has been around a while and should work as is when
3641 you get the config right.
3646 It is essential to remember this, since it has some impact on the C
3647 code for the initialization procedures:
3649 * Initialized global data (data segment) is read-only. Do not attempt
3652 * Do not use any unitialized global data (or implicitely initialized
3653 as zero data - BSS segment) at all - this is undefined, initiali-
3654 zation is performed later (when relocating to RAM).
3656 * Stack space is very limited. Avoid big data buffers or things like
3659 Having only the stack as writable memory limits means we cannot use
3660 normal global data to share information beween the code. But it
3661 turned out that the implementation of U-Boot can be greatly
3662 simplified by making a global data structure (gd_t) available to all
3663 functions. We could pass a pointer to this data as argument to _all_
3664 functions, but this would bloat the code. Instead we use a feature of
3665 the GCC compiler (Global Register Variables) to share the data: we
3666 place a pointer (gd) to the global data into a register which we
3667 reserve for this purpose.
3669 When choosing a register for such a purpose we are restricted by the
3670 relevant (E)ABI specifications for the current architecture, and by
3671 GCC's implementation.
3673 For PowerPC, the following registers have specific use:
3675 R2: reserved for system use
3676 R3-R4: parameter passing and return values
3677 R5-R10: parameter passing
3678 R13: small data area pointer
3682 (U-Boot also uses R14 as internal GOT pointer.)
3684 ==> U-Boot will use R2 to hold a pointer to the global data
3686 Note: on PPC, we could use a static initializer (since the
3687 address of the global data structure is known at compile time),
3688 but it turned out that reserving a register results in somewhat
3689 smaller code - although the code savings are not that big (on
3690 average for all boards 752 bytes for the whole U-Boot image,
3691 624 text + 127 data).
3693 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3694 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3696 ==> U-Boot will use P5 to hold a pointer to the global data
3698 On ARM, the following registers are used:
3700 R0: function argument word/integer result
3701 R1-R3: function argument word
3703 R10: stack limit (used only if stack checking if enabled)
3704 R11: argument (frame) pointer
3705 R12: temporary workspace
3708 R15: program counter
3710 ==> U-Boot will use R8 to hold a pointer to the global data
3712 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3713 or current versions of GCC may "optimize" the code too much.
3718 U-Boot runs in system state and uses physical addresses, i.e. the
3719 MMU is not used either for address mapping nor for memory protection.
3721 The available memory is mapped to fixed addresses using the memory
3722 controller. In this process, a contiguous block is formed for each
3723 memory type (Flash, SDRAM, SRAM), even when it consists of several
3724 physical memory banks.
3726 U-Boot is installed in the first 128 kB of the first Flash bank (on
3727 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3728 booting and sizing and initializing DRAM, the code relocates itself
3729 to the upper end of DRAM. Immediately below the U-Boot code some
3730 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3731 configuration setting]. Below that, a structure with global Board
3732 Info data is placed, followed by the stack (growing downward).
3734 Additionally, some exception handler code is copied to the low 8 kB
3735 of DRAM (0x00000000 ... 0x00001FFF).
3737 So a typical memory configuration with 16 MB of DRAM could look like
3740 0x0000 0000 Exception Vector code
3743 0x0000 2000 Free for Application Use
3749 0x00FB FF20 Monitor Stack (Growing downward)
3750 0x00FB FFAC Board Info Data and permanent copy of global data
3751 0x00FC 0000 Malloc Arena
3754 0x00FE 0000 RAM Copy of Monitor Code
3755 ... eventually: LCD or video framebuffer
3756 ... eventually: pRAM (Protected RAM - unchanged by reset)
3757 0x00FF FFFF [End of RAM]
3760 System Initialization:
3761 ----------------------
3763 In the reset configuration, U-Boot starts at the reset entry point
3764 (on most PowerPC systens at address 0x00000100). Because of the reset
3765 configuration for CS0# this is a mirror of the onboard Flash memory.
3766 To be able to re-map memory U-Boot then jumps to its link address.
3767 To be able to implement the initialization code in C, a (small!)
3768 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3769 which provide such a feature like MPC8xx or MPC8260), or in a locked
3770 part of the data cache. After that, U-Boot initializes the CPU core,
3771 the caches and the SIU.
3773 Next, all (potentially) available memory banks are mapped using a
3774 preliminary mapping. For example, we put them on 512 MB boundaries
3775 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3776 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3777 programmed for SDRAM access. Using the temporary configuration, a
3778 simple memory test is run that determines the size of the SDRAM
3781 When there is more than one SDRAM bank, and the banks are of
3782 different size, the largest is mapped first. For equal size, the first
3783 bank (CS2#) is mapped first. The first mapping is always for address
3784 0x00000000, with any additional banks following immediately to create
3785 contiguous memory starting from 0.
3787 Then, the monitor installs itself at the upper end of the SDRAM area
3788 and allocates memory for use by malloc() and for the global Board
3789 Info data; also, the exception vector code is copied to the low RAM
3790 pages, and the final stack is set up.
3792 Only after this relocation will you have a "normal" C environment;
3793 until that you are restricted in several ways, mostly because you are
3794 running from ROM, and because the code will have to be relocated to a
3798 U-Boot Porting Guide:
3799 ----------------------
3801 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3805 int main (int argc, char *argv[])
3807 sighandler_t no_more_time;
3809 signal (SIGALRM, no_more_time);
3810 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3812 if (available_money > available_manpower) {
3813 pay consultant to port U-Boot;
3817 Download latest U-Boot source;
3819 Subscribe to u-boot-users mailing list;
3822 email ("Hi, I am new to U-Boot, how do I get started?");
3826 Read the README file in the top level directory;
3827 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3828 Read the source, Luke;
3831 if (available_money > toLocalCurrency ($2500)) {
3834 Add a lot of aggravation and time;
3837 Create your own board support subdirectory;
3839 Create your own board config file;
3843 Add / modify source code;
3847 email ("Hi, I am having problems...");
3849 Send patch file to Wolfgang;
3854 void no_more_time (int sig)
3863 All contributions to U-Boot should conform to the Linux kernel
3864 coding style; see the file "Documentation/CodingStyle" and the script
3865 "scripts/Lindent" in your Linux kernel source directory. In sources
3866 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3867 spaces before parameters to function calls) is actually used.
3869 Source files originating from a different project (for example the
3870 MTD subsystem) are generally exempt from these guidelines and are not
3871 reformated to ease subsequent migration to newer versions of those
3874 Please note that U-Boot is implemented in C (and to some small parts in
3875 Assembler); no C++ is used, so please do not use C++ style comments (//)
3878 Please also stick to the following formatting rules:
3879 - remove any trailing white space
3880 - use TAB characters for indentation, not spaces
3881 - make sure NOT to use DOS '\r\n' line feeds
3882 - do not add more than 2 empty lines to source files
3883 - do not add trailing empty lines to source files
3885 Submissions which do not conform to the standards may be returned
3886 with a request to reformat the changes.
3892 Since the number of patches for U-Boot is growing, we need to
3893 establish some rules. Submissions which do not conform to these rules
3894 may be rejected, even when they contain important and valuable stuff.
3896 Patches shall be sent to the u-boot-users mailing list.
3898 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3900 When you send a patch, please include the following information with
3903 * For bug fixes: a description of the bug and how your patch fixes
3904 this bug. Please try to include a way of demonstrating that the
3905 patch actually fixes something.
3907 * For new features: a description of the feature and your
3910 * A CHANGELOG entry as plaintext (separate from the patch)
3912 * For major contributions, your entry to the CREDITS file
3914 * When you add support for a new board, don't forget to add this
3915 board to the MAKEALL script, too.
3917 * If your patch adds new configuration options, don't forget to
3918 document these in the README file.
3920 * The patch itself. If you are using git (which is *strongly*
3921 recommended) you can easily generate the patch using the
3922 "git-format-patch". If you then use "git-send-email" to send it to
3923 the U-Boot mailing list, you will avoid most of the common problems
3924 with some other mail clients.
3926 If you cannot use git, use "diff -purN OLD NEW". If your version of
3927 diff does not support these options, then get the latest version of
3930 The current directory when running this command shall be the parent
3931 directory of the U-Boot source tree (i. e. please make sure that
3932 your patch includes sufficient directory information for the
3935 We prefer patches as plain text. MIME attachments are discouraged,
3936 and compressed attachments must not be used.
3938 * If one logical set of modifications affects or creates several
3939 files, all these changes shall be submitted in a SINGLE patch file.
3941 * Changesets that contain different, unrelated modifications shall be
3942 submitted as SEPARATE patches, one patch per changeset.
3947 * Before sending the patch, run the MAKEALL script on your patched
3948 source tree and make sure that no errors or warnings are reported
3949 for any of the boards.
3951 * Keep your modifications to the necessary minimum: A patch
3952 containing several unrelated changes or arbitrary reformats will be
3953 returned with a request to re-formatting / split it.
3955 * If you modify existing code, make sure that your new code does not
3956 add to the memory footprint of the code ;-) Small is beautiful!
3957 When adding new features, these should compile conditionally only
3958 (using #ifdef), and the resulting code with the new feature
3959 disabled must not need more memory than the old code without your
3962 * Remember that there is a size limit of 40 kB per message on the
3963 u-boot-users mailing list. Bigger patches will be moderated. If
3964 they are reasonable and not bigger than 100 kB, they will be
3965 acknowledged. Even bigger patches should be avoided.
projects / oweals / u-boot.git / blob