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:
965 CONFIG_NEC_NL6448AC33:
967 NEC NL6448AC33-18. Active, color, single scan.
969 CONFIG_NEC_NL6448BC20
971 NEC NL6448BC20-08. 6.5", 640x480.
972 Active, color, single scan.
974 CONFIG_NEC_NL6448BC33_54
976 NEC NL6448BC33-54. 10.4", 640x480.
977 Active, color, single scan.
981 Sharp 320x240. Active, color, single scan.
982 It isn't 16x9, and I am not sure what it is.
984 CONFIG_SHARP_LQ64D341
986 Sharp LQ64D341 display, 640x480.
987 Active, color, single scan.
991 HLD1045 display, 640x480.
992 Active, color, single scan.
996 Optrex CBL50840-2 NF-FW 99 22 M5
998 Hitachi LMG6912RPFC-00T
1002 320x240. Black & white.
1004 Normally display is black on white background; define
1005 CFG_WHITE_ON_BLACK to get it inverted.
1007 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1009 If this option is set, the environment is checked for
1010 a variable "splashimage". If found, the usual display
1011 of logo, copyright and system information on the LCD
1012 is suppressed and the BMP image at the address
1013 specified in "splashimage" is loaded instead. The
1014 console is redirected to the "nulldev", too. This
1015 allows for a "silent" boot where a splash screen is
1016 loaded very quickly after power-on.
1018 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1020 If this option is set, additionally to standard BMP
1021 images, gzipped BMP images can be displayed via the
1022 splashscreen support or the bmp command.
1024 - Compression support:
1027 If this option is set, support for bzip2 compressed
1028 images is included. If not, only uncompressed and gzip
1029 compressed images are supported.
1031 NOTE: the bzip2 algorithm requires a lot of RAM, so
1032 the malloc area (as defined by CFG_MALLOC_LEN) should
1038 The address of PHY on MII bus.
1040 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1042 The clock frequency of the MII bus
1046 If this option is set, support for speed/duplex
1047 detection of Gigabit PHY is included.
1049 CONFIG_PHY_RESET_DELAY
1051 Some PHY like Intel LXT971A need extra delay after
1052 reset before any MII register access is possible.
1053 For such PHY, set this option to the usec delay
1054 required. (minimum 300usec for LXT971A)
1056 CONFIG_PHY_CMD_DELAY (ppc4xx)
1058 Some PHY like Intel LXT971A need extra delay after
1059 command issued before MII status register can be read
1066 Define a default value for ethernet address to use
1067 for the respective ethernet interface, in case this
1068 is not determined automatically.
1073 Define a default value for the IP address to use for
1074 the default ethernet interface, in case this is not
1075 determined through e.g. bootp.
1077 - Server IP address:
1080 Defines a default value for theIP address of a TFTP
1081 server to contact when using the "tftboot" command.
1083 - Multicast TFTP Mode:
1086 Defines whether you want to support multicast TFTP as per
1087 rfc-2090; for example to work with atftp. Lets lots of targets
1088 tftp down the same boot image concurrently. Note: the ethernet
1089 driver in use must provide a function: mcast() to join/leave a
1092 CONFIG_BOOTP_RANDOM_DELAY
1093 - BOOTP Recovery Mode:
1094 CONFIG_BOOTP_RANDOM_DELAY
1096 If you have many targets in a network that try to
1097 boot using BOOTP, you may want to avoid that all
1098 systems send out BOOTP requests at precisely the same
1099 moment (which would happen for instance at recovery
1100 from a power failure, when all systems will try to
1101 boot, thus flooding the BOOTP server. Defining
1102 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1103 inserted before sending out BOOTP requests. The
1104 following delays are inserted then:
1106 1st BOOTP request: delay 0 ... 1 sec
1107 2nd BOOTP request: delay 0 ... 2 sec
1108 3rd BOOTP request: delay 0 ... 4 sec
1110 BOOTP requests: delay 0 ... 8 sec
1112 - DHCP Advanced Options:
1113 You can fine tune the DHCP functionality by defining
1114 CONFIG_BOOTP_* symbols:
1116 CONFIG_BOOTP_SUBNETMASK
1117 CONFIG_BOOTP_GATEWAY
1118 CONFIG_BOOTP_HOSTNAME
1119 CONFIG_BOOTP_NISDOMAIN
1120 CONFIG_BOOTP_BOOTPATH
1121 CONFIG_BOOTP_BOOTFILESIZE
1124 CONFIG_BOOTP_SEND_HOSTNAME
1125 CONFIG_BOOTP_NTPSERVER
1126 CONFIG_BOOTP_TIMEOFFSET
1127 CONFIG_BOOTP_VENDOREX
1129 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1130 environment variable, not the BOOTP server.
1132 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1133 serverip from a DHCP server, it is possible that more
1134 than one DNS serverip is offered to the client.
1135 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1136 serverip will be stored in the additional environment
1137 variable "dnsip2". The first DNS serverip is always
1138 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1141 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1142 to do a dynamic update of a DNS server. To do this, they
1143 need the hostname of the DHCP requester.
1144 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1145 of the "hostname" environment variable is passed as
1146 option 12 to the DHCP server.
1148 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1150 A 32bit value in microseconds for a delay between
1151 receiving a "DHCP Offer" and sending the "DHCP Request".
1152 This fixes a problem with certain DHCP servers that don't
1153 respond 100% of the time to a "DHCP request". E.g. On an
1154 AT91RM9200 processor running at 180MHz, this delay needed
1155 to be *at least* 15,000 usec before a Windows Server 2003
1156 DHCP server would reply 100% of the time. I recommend at
1157 least 50,000 usec to be safe. The alternative is to hope
1158 that one of the retries will be successful but note that
1159 the DHCP timeout and retry process takes a longer than
1163 CONFIG_CDP_DEVICE_ID
1165 The device id used in CDP trigger frames.
1167 CONFIG_CDP_DEVICE_ID_PREFIX
1169 A two character string which is prefixed to the MAC address
1174 A printf format string which contains the ascii name of
1175 the port. Normally is set to "eth%d" which sets
1176 eth0 for the first ethernet, eth1 for the second etc.
1178 CONFIG_CDP_CAPABILITIES
1180 A 32bit integer which indicates the device capabilities;
1181 0x00000010 for a normal host which does not forwards.
1185 An ascii string containing the version of the software.
1189 An ascii string containing the name of the platform.
1193 A 32bit integer sent on the trigger.
1195 CONFIG_CDP_POWER_CONSUMPTION
1197 A 16bit integer containing the power consumption of the
1198 device in .1 of milliwatts.
1200 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1202 A byte containing the id of the VLAN.
1204 - Status LED: CONFIG_STATUS_LED
1206 Several configurations allow to display the current
1207 status using a LED. For instance, the LED will blink
1208 fast while running U-Boot code, stop blinking as
1209 soon as a reply to a BOOTP request was received, and
1210 start blinking slow once the Linux kernel is running
1211 (supported by a status LED driver in the Linux
1212 kernel). Defining CONFIG_STATUS_LED enables this
1215 - CAN Support: CONFIG_CAN_DRIVER
1217 Defining CONFIG_CAN_DRIVER enables CAN driver support
1218 on those systems that support this (optional)
1219 feature, like the TQM8xxL modules.
1221 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1223 These enable I2C serial bus commands. Defining either of
1224 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1225 include the appropriate I2C driver for the selected cpu.
1227 This will allow you to use i2c commands at the u-boot
1228 command line (as long as you set CONFIG_CMD_I2C in
1229 CONFIG_COMMANDS) and communicate with i2c based realtime
1230 clock chips. See common/cmd_i2c.c for a description of the
1231 command line interface.
1233 CONFIG_I2C_CMD_TREE is a recommended option that places
1234 all I2C commands under a single 'i2c' root command. The
1235 older 'imm', 'imd', 'iprobe' etc. commands are considered
1236 deprecated and may disappear in the future.
1238 CONFIG_HARD_I2C selects a hardware I2C controller.
1240 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1241 bit-banging) driver instead of CPM or similar hardware
1244 There are several other quantities that must also be
1245 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1247 In both cases you will need to define CFG_I2C_SPEED
1248 to be the frequency (in Hz) at which you wish your i2c bus
1249 to run and CFG_I2C_SLAVE to be the address of this node (ie
1250 the cpu's i2c node address).
1252 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1253 sets the cpu up as a master node and so its address should
1254 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1255 p.16-473). So, set CFG_I2C_SLAVE to 0.
1257 That's all that's required for CONFIG_HARD_I2C.
1259 If you use the software i2c interface (CONFIG_SOFT_I2C)
1260 then the following macros need to be defined (examples are
1261 from include/configs/lwmon.h):
1265 (Optional). Any commands necessary to enable the I2C
1266 controller or configure ports.
1268 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1272 (Only for MPC8260 CPU). The I/O port to use (the code
1273 assumes both bits are on the same port). Valid values
1274 are 0..3 for ports A..D.
1278 The code necessary to make the I2C data line active
1279 (driven). If the data line is open collector, this
1282 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1286 The code necessary to make the I2C data line tri-stated
1287 (inactive). If the data line is open collector, this
1290 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1294 Code that returns TRUE if the I2C data line is high,
1297 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1301 If <bit> is TRUE, sets the I2C data line high. If it
1302 is FALSE, it clears it (low).
1304 eg: #define I2C_SDA(bit) \
1305 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1306 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1310 If <bit> is TRUE, sets the I2C clock line high. If it
1311 is FALSE, it clears it (low).
1313 eg: #define I2C_SCL(bit) \
1314 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1315 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1319 This delay is invoked four times per clock cycle so this
1320 controls the rate of data transfer. The data rate thus
1321 is 1 / (I2C_DELAY * 4). Often defined to be something
1324 #define I2C_DELAY udelay(2)
1328 When a board is reset during an i2c bus transfer
1329 chips might think that the current transfer is still
1330 in progress. On some boards it is possible to access
1331 the i2c SCLK line directly, either by using the
1332 processor pin as a GPIO or by having a second pin
1333 connected to the bus. If this option is defined a
1334 custom i2c_init_board() routine in boards/xxx/board.c
1335 is run early in the boot sequence.
1337 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1339 This option enables configuration of bi_iic_fast[] flags
1340 in u-boot bd_info structure based on u-boot environment
1341 variable "i2cfast". (see also i2cfast)
1343 CONFIG_I2C_MULTI_BUS
1345 This option allows the use of multiple I2C buses, each of which
1346 must have a controller. At any point in time, only one bus is
1347 active. To switch to a different bus, use the 'i2c dev' command.
1348 Note that bus numbering is zero-based.
1352 This option specifies a list of I2C devices that will be skipped
1353 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1354 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1355 pairs. Otherwise, specify a 1D array of device addresses
1358 #undef CONFIG_I2C_MULTI_BUS
1359 #define CFG_I2C_NOPROBES {0x50,0x68}
1361 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1363 #define CONFIG_I2C_MULTI_BUS
1364 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1366 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1370 If defined, then this indicates the I2C bus number for DDR SPD.
1371 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1375 If defined, then this indicates the I2C bus number for the RTC.
1376 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1380 If defined, then this indicates the I2C bus number for the DTT.
1381 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1385 Define this option if you want to use Freescale's I2C driver in
1386 drivers/i2c/fsl_i2c.c.
1389 - SPI Support: CONFIG_SPI
1391 Enables SPI driver (so far only tested with
1392 SPI EEPROM, also an instance works with Crystal A/D and
1393 D/As on the SACSng board)
1397 Enables extended (16-bit) SPI EEPROM addressing.
1398 (symmetrical to CONFIG_I2C_X)
1402 Enables a software (bit-bang) SPI driver rather than
1403 using hardware support. This is a general purpose
1404 driver that only requires three general I/O port pins
1405 (two outputs, one input) to function. If this is
1406 defined, the board configuration must define several
1407 SPI configuration items (port pins to use, etc). For
1408 an example, see include/configs/sacsng.h.
1412 Enables a hardware SPI driver for general-purpose reads
1413 and writes. As with CONFIG_SOFT_SPI, the board configuration
1414 must define a list of chip-select function pointers.
1415 Currently supported on some MPC8xxx processors. For an
1416 example, see include/configs/mpc8349emds.h.
1420 Enables the driver for the SPI controllers on i.MX and MXC
1421 SoCs. Currently only i.MX31 is supported.
1423 - FPGA Support: CONFIG_FPGA
1425 Enables FPGA subsystem.
1427 CONFIG_FPGA_<vendor>
1429 Enables support for specific chip vendors.
1432 CONFIG_FPGA_<family>
1434 Enables support for FPGA family.
1435 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1439 Specify the number of FPGA devices to support.
1441 CFG_FPGA_PROG_FEEDBACK
1443 Enable printing of hash marks during FPGA configuration.
1447 Enable checks on FPGA configuration interface busy
1448 status by the configuration function. This option
1449 will require a board or device specific function to
1454 If defined, a function that provides delays in the FPGA
1455 configuration driver.
1457 CFG_FPGA_CHECK_CTRLC
1458 Allow Control-C to interrupt FPGA configuration
1460 CFG_FPGA_CHECK_ERROR
1462 Check for configuration errors during FPGA bitfile
1463 loading. For example, abort during Virtex II
1464 configuration if the INIT_B line goes low (which
1465 indicated a CRC error).
1469 Maximum time to wait for the INIT_B line to deassert
1470 after PROB_B has been deasserted during a Virtex II
1471 FPGA configuration sequence. The default time is 500
1476 Maximum time to wait for BUSY to deassert during
1477 Virtex II FPGA configuration. The default is 5 mS.
1479 CFG_FPGA_WAIT_CONFIG
1481 Time to wait after FPGA configuration. The default is
1484 - Configuration Management:
1487 If defined, this string will be added to the U-Boot
1488 version information (U_BOOT_VERSION)
1490 - Vendor Parameter Protection:
1492 U-Boot considers the values of the environment
1493 variables "serial#" (Board Serial Number) and
1494 "ethaddr" (Ethernet Address) to be parameters that
1495 are set once by the board vendor / manufacturer, and
1496 protects these variables from casual modification by
1497 the user. Once set, these variables are read-only,
1498 and write or delete attempts are rejected. You can
1499 change this behviour:
1501 If CONFIG_ENV_OVERWRITE is #defined in your config
1502 file, the write protection for vendor parameters is
1503 completely disabled. Anybody can change or delete
1506 Alternatively, if you #define _both_ CONFIG_ETHADDR
1507 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1508 ethernet address is installed in the environment,
1509 which can be changed exactly ONCE by the user. [The
1510 serial# is unaffected by this, i. e. it remains
1516 Define this variable to enable the reservation of
1517 "protected RAM", i. e. RAM which is not overwritten
1518 by U-Boot. Define CONFIG_PRAM to hold the number of
1519 kB you want to reserve for pRAM. You can overwrite
1520 this default value by defining an environment
1521 variable "pram" to the number of kB you want to
1522 reserve. Note that the board info structure will
1523 still show the full amount of RAM. If pRAM is
1524 reserved, a new environment variable "mem" will
1525 automatically be defined to hold the amount of
1526 remaining RAM in a form that can be passed as boot
1527 argument to Linux, for instance like that:
1529 setenv bootargs ... mem=\${mem}
1532 This way you can tell Linux not to use this memory,
1533 either, which results in a memory region that will
1534 not be affected by reboots.
1536 *WARNING* If your board configuration uses automatic
1537 detection of the RAM size, you must make sure that
1538 this memory test is non-destructive. So far, the
1539 following board configurations are known to be
1542 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1543 HERMES, IP860, RPXlite, LWMON, LANTEC,
1544 PCU_E, FLAGADM, TQM8260
1549 Define this variable to stop the system in case of a
1550 fatal error, so that you have to reset it manually.
1551 This is probably NOT a good idea for an embedded
1552 system where you want to system to reboot
1553 automatically as fast as possible, but it may be
1554 useful during development since you can try to debug
1555 the conditions that lead to the situation.
1557 CONFIG_NET_RETRY_COUNT
1559 This variable defines the number of retries for
1560 network operations like ARP, RARP, TFTP, or BOOTP
1561 before giving up the operation. If not defined, a
1562 default value of 5 is used.
1566 Timeout waiting for an ARP reply in milliseconds.
1568 - Command Interpreter:
1569 CONFIG_AUTO_COMPLETE
1571 Enable auto completion of commands using TAB.
1573 Note that this feature has NOT been implemented yet
1574 for the "hush" shell.
1579 Define this variable to enable the "hush" shell (from
1580 Busybox) as command line interpreter, thus enabling
1581 powerful command line syntax like
1582 if...then...else...fi conditionals or `&&' and '||'
1583 constructs ("shell scripts").
1585 If undefined, you get the old, much simpler behaviour
1586 with a somewhat smaller memory footprint.
1591 This defines the secondary prompt string, which is
1592 printed when the command interpreter needs more input
1593 to complete a command. Usually "> ".
1597 In the current implementation, the local variables
1598 space and global environment variables space are
1599 separated. Local variables are those you define by
1600 simply typing `name=value'. To access a local
1601 variable later on, you have write `$name' or
1602 `${name}'; to execute the contents of a variable
1603 directly type `$name' at the command prompt.
1605 Global environment variables are those you use
1606 setenv/printenv to work with. To run a command stored
1607 in such a variable, you need to use the run command,
1608 and you must not use the '$' sign to access them.
1610 To store commands and special characters in a
1611 variable, please use double quotation marks
1612 surrounding the whole text of the variable, instead
1613 of the backslashes before semicolons and special
1616 - Commandline Editing and History:
1617 CONFIG_CMDLINE_EDITING
1619 Enable editiong and History functions for interactive
1620 commandline input operations
1622 - Default Environment:
1623 CONFIG_EXTRA_ENV_SETTINGS
1625 Define this to contain any number of null terminated
1626 strings (variable = value pairs) that will be part of
1627 the default environment compiled into the boot image.
1629 For example, place something like this in your
1630 board's config file:
1632 #define CONFIG_EXTRA_ENV_SETTINGS \
1636 Warning: This method is based on knowledge about the
1637 internal format how the environment is stored by the
1638 U-Boot code. This is NOT an official, exported
1639 interface! Although it is unlikely that this format
1640 will change soon, there is no guarantee either.
1641 You better know what you are doing here.
1643 Note: overly (ab)use of the default environment is
1644 discouraged. Make sure to check other ways to preset
1645 the environment like the autoscript function or the
1648 - DataFlash Support:
1649 CONFIG_HAS_DATAFLASH
1651 Defining this option enables DataFlash features and
1652 allows to read/write in Dataflash via the standard
1655 - SystemACE Support:
1658 Adding this option adds support for Xilinx SystemACE
1659 chips attached via some sort of local bus. The address
1660 of the chip must alsh be defined in the
1661 CFG_SYSTEMACE_BASE macro. For example:
1663 #define CONFIG_SYSTEMACE
1664 #define CFG_SYSTEMACE_BASE 0xf0000000
1666 When SystemACE support is added, the "ace" device type
1667 becomes available to the fat commands, i.e. fatls.
1669 - TFTP Fixed UDP Port:
1672 If this is defined, the environment variable tftpsrcp
1673 is used to supply the TFTP UDP source port value.
1674 If tftpsrcp isn't defined, the normal pseudo-random port
1675 number generator is used.
1677 Also, the environment variable tftpdstp is used to supply
1678 the TFTP UDP destination port value. If tftpdstp isn't
1679 defined, the normal port 69 is used.
1681 The purpose for tftpsrcp is to allow a TFTP server to
1682 blindly start the TFTP transfer using the pre-configured
1683 target IP address and UDP port. This has the effect of
1684 "punching through" the (Windows XP) firewall, allowing
1685 the remainder of the TFTP transfer to proceed normally.
1686 A better solution is to properly configure the firewall,
1687 but sometimes that is not allowed.
1689 - Show boot progress:
1690 CONFIG_SHOW_BOOT_PROGRESS
1692 Defining this option allows to add some board-
1693 specific code (calling a user-provided function
1694 "show_boot_progress(int)") that enables you to show
1695 the system's boot progress on some display (for
1696 example, some LED's) on your board. At the moment,
1697 the following checkpoints are implemented:
1699 Legacy uImage format:
1702 1 common/cmd_bootm.c before attempting to boot an image
1703 -1 common/cmd_bootm.c Image header has bad magic number
1704 2 common/cmd_bootm.c Image header has correct magic number
1705 -2 common/cmd_bootm.c Image header has bad checksum
1706 3 common/cmd_bootm.c Image header has correct checksum
1707 -3 common/cmd_bootm.c Image data has bad checksum
1708 4 common/cmd_bootm.c Image data has correct checksum
1709 -4 common/cmd_bootm.c Image is for unsupported architecture
1710 5 common/cmd_bootm.c Architecture check OK
1711 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1712 6 common/cmd_bootm.c Image Type check OK
1713 -6 common/cmd_bootm.c gunzip uncompression error
1714 -7 common/cmd_bootm.c Unimplemented compression type
1715 7 common/cmd_bootm.c Uncompression OK
1716 8 common/cmd_bootm.c No uncompress/copy overwrite error
1717 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1719 9 common/image.c Start initial ramdisk verification
1720 -10 common/image.c Ramdisk header has bad magic number
1721 -11 common/image.c Ramdisk header has bad checksum
1722 10 common/image.c Ramdisk header is OK
1723 -12 common/image.c Ramdisk data has bad checksum
1724 11 common/image.c Ramdisk data has correct checksum
1725 12 common/image.c Ramdisk verification complete, start loading
1726 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1727 13 common/image.c Start multifile image verification
1728 14 common/image.c No initial ramdisk, no multifile, continue.
1730 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1732 -30 lib_ppc/board.c Fatal error, hang the system
1733 -31 post/post.c POST test failed, detected by post_output_backlog()
1734 -32 post/post.c POST test failed, detected by post_run_single()
1736 34 common/cmd_doc.c before loading a Image from a DOC device
1737 -35 common/cmd_doc.c Bad usage of "doc" command
1738 35 common/cmd_doc.c correct usage of "doc" command
1739 -36 common/cmd_doc.c No boot device
1740 36 common/cmd_doc.c correct boot device
1741 -37 common/cmd_doc.c Unknown Chip ID on boot device
1742 37 common/cmd_doc.c correct chip ID found, device available
1743 -38 common/cmd_doc.c Read Error on boot device
1744 38 common/cmd_doc.c reading Image header from DOC device OK
1745 -39 common/cmd_doc.c Image header has bad magic number
1746 39 common/cmd_doc.c Image header has correct magic number
1747 -40 common/cmd_doc.c Error reading Image from DOC device
1748 40 common/cmd_doc.c Image header has correct magic number
1749 41 common/cmd_ide.c before loading a Image from a IDE device
1750 -42 common/cmd_ide.c Bad usage of "ide" command
1751 42 common/cmd_ide.c correct usage of "ide" command
1752 -43 common/cmd_ide.c No boot device
1753 43 common/cmd_ide.c boot device found
1754 -44 common/cmd_ide.c Device not available
1755 44 common/cmd_ide.c Device available
1756 -45 common/cmd_ide.c wrong partition selected
1757 45 common/cmd_ide.c partition selected
1758 -46 common/cmd_ide.c Unknown partition table
1759 46 common/cmd_ide.c valid partition table found
1760 -47 common/cmd_ide.c Invalid partition type
1761 47 common/cmd_ide.c correct partition type
1762 -48 common/cmd_ide.c Error reading Image Header on boot device
1763 48 common/cmd_ide.c reading Image Header from IDE device OK
1764 -49 common/cmd_ide.c Image header has bad magic number
1765 49 common/cmd_ide.c Image header has correct magic number
1766 -50 common/cmd_ide.c Image header has bad checksum
1767 50 common/cmd_ide.c Image header has correct checksum
1768 -51 common/cmd_ide.c Error reading Image from IDE device
1769 51 common/cmd_ide.c reading Image from IDE device OK
1770 52 common/cmd_nand.c before loading a Image from a NAND device
1771 -53 common/cmd_nand.c Bad usage of "nand" command
1772 53 common/cmd_nand.c correct usage of "nand" command
1773 -54 common/cmd_nand.c No boot device
1774 54 common/cmd_nand.c boot device found
1775 -55 common/cmd_nand.c Unknown Chip ID on boot device
1776 55 common/cmd_nand.c correct chip ID found, device available
1777 -56 common/cmd_nand.c Error reading Image Header on boot device
1778 56 common/cmd_nand.c reading Image Header from NAND device OK
1779 -57 common/cmd_nand.c Image header has bad magic number
1780 57 common/cmd_nand.c Image header has correct magic number
1781 -58 common/cmd_nand.c Error reading Image from NAND device
1782 58 common/cmd_nand.c reading Image from NAND device OK
1784 -60 common/env_common.c Environment has a bad CRC, using default
1786 64 net/eth.c starting with Ethernetconfiguration.
1787 -64 net/eth.c no Ethernet found.
1788 65 net/eth.c Ethernet found.
1790 -80 common/cmd_net.c usage wrong
1791 80 common/cmd_net.c before calling NetLoop()
1792 -81 common/cmd_net.c some error in NetLoop() occured
1793 81 common/cmd_net.c NetLoop() back without error
1794 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1795 82 common/cmd_net.c trying automatic boot
1796 83 common/cmd_net.c running autoscript
1797 -83 common/cmd_net.c some error in automatic boot or autoscript
1798 84 common/cmd_net.c end without errors
1803 100 common/cmd_bootm.c Kernel FIT Image has correct format
1804 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1805 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1806 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1807 102 common/cmd_bootm.c Kernel unit name specified
1808 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1809 103 common/cmd_bootm.c Found configuration node
1810 104 common/cmd_bootm.c Got kernel subimage node offset
1811 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1812 105 common/cmd_bootm.c Kernel subimage hash verification OK
1813 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1814 106 common/cmd_bootm.c Architecture check OK
1815 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1816 107 common/cmd_bootm.c Kernel subimge type OK
1817 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1818 108 common/cmd_bootm.c Got kernel subimage data/size
1819 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1820 -109 common/cmd_bootm.c Can't get kernel subimage type
1821 -110 common/cmd_bootm.c Can't get kernel subimage comp
1822 -111 common/cmd_bootm.c Can't get kernel subimage os
1823 -112 common/cmd_bootm.c Can't get kernel subimage load address
1824 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1826 120 common/image.c Start initial ramdisk verification
1827 -120 common/image.c Ramdisk FIT image has incorrect format
1828 121 common/image.c Ramdisk FIT image has correct format
1829 122 common/image.c No Ramdisk subimage unit name, using configuration
1830 -122 common/image.c Can't get configuration for ramdisk subimage
1831 123 common/image.c Ramdisk unit name specified
1832 -124 common/image.c Can't get ramdisk subimage node offset
1833 125 common/image.c Got ramdisk subimage node offset
1834 -125 common/image.c Ramdisk subimage hash verification failed
1835 126 common/image.c Ramdisk subimage hash verification OK
1836 -126 common/image.c Ramdisk subimage for unsupported architecture
1837 127 common/image.c Architecture check OK
1838 -127 common/image.c Can't get ramdisk subimage data/size
1839 128 common/image.c Got ramdisk subimage data/size
1840 129 common/image.c Can't get ramdisk load address
1841 -129 common/image.c Got ramdisk load address
1843 -130 common/cmd_doc.c Icorrect FIT image format
1844 131 common/cmd_doc.c FIT image format OK
1846 -140 common/cmd_ide.c Icorrect FIT image format
1847 141 common/cmd_ide.c FIT image format OK
1849 -150 common/cmd_nand.c Icorrect FIT image format
1850 151 common/cmd_nand.c FIT image format OK
1856 [so far only for SMDK2400 and TRAB boards]
1858 - Modem support endable:
1859 CONFIG_MODEM_SUPPORT
1861 - RTS/CTS Flow control enable:
1864 - Modem debug support:
1865 CONFIG_MODEM_SUPPORT_DEBUG
1867 Enables debugging stuff (char screen[1024], dbg())
1868 for modem support. Useful only with BDI2000.
1870 - Interrupt support (PPC):
1872 There are common interrupt_init() and timer_interrupt()
1873 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1874 for cpu specific initialization. interrupt_init_cpu()
1875 should set decrementer_count to appropriate value. If
1876 cpu resets decrementer automatically after interrupt
1877 (ppc4xx) it should set decrementer_count to zero.
1878 timer_interrupt() calls timer_interrupt_cpu() for cpu
1879 specific handling. If board has watchdog / status_led
1880 / other_activity_monitor it works automatically from
1881 general timer_interrupt().
1885 In the target system modem support is enabled when a
1886 specific key (key combination) is pressed during
1887 power-on. Otherwise U-Boot will boot normally
1888 (autoboot). The key_pressed() fuction is called from
1889 board_init(). Currently key_pressed() is a dummy
1890 function, returning 1 and thus enabling modem
1893 If there are no modem init strings in the
1894 environment, U-Boot proceed to autoboot; the
1895 previous output (banner, info printfs) will be
1898 See also: doc/README.Modem
1901 Configuration Settings:
1902 -----------------------
1904 - CFG_LONGHELP: Defined when you want long help messages included;
1905 undefine this when you're short of memory.
1907 - CFG_PROMPT: This is what U-Boot prints on the console to
1908 prompt for user input.
1910 - CFG_CBSIZE: Buffer size for input from the Console
1912 - CFG_PBSIZE: Buffer size for Console output
1914 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1916 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1917 the application (usually a Linux kernel) when it is
1920 - CFG_BAUDRATE_TABLE:
1921 List of legal baudrate settings for this board.
1923 - CFG_CONSOLE_INFO_QUIET
1924 Suppress display of console information at boot.
1926 - CFG_CONSOLE_IS_IN_ENV
1927 If the board specific function
1928 extern int overwrite_console (void);
1929 returns 1, the stdin, stderr and stdout are switched to the
1930 serial port, else the settings in the environment are used.
1932 - CFG_CONSOLE_OVERWRITE_ROUTINE
1933 Enable the call to overwrite_console().
1935 - CFG_CONSOLE_ENV_OVERWRITE
1936 Enable overwrite of previous console environment settings.
1938 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1939 Begin and End addresses of the area used by the
1943 Enable an alternate, more extensive memory test.
1945 - CFG_MEMTEST_SCRATCH:
1946 Scratch address used by the alternate memory test
1947 You only need to set this if address zero isn't writeable
1949 - CFG_MEM_TOP_HIDE (PPC only):
1950 If CFG_MEM_TOP_HIDE is defined in the board config header,
1951 this specified memory area will get subtracted from the top
1952 (end) of ram and won't get "touched" at all by U-Boot. By
1953 fixing up gd->ram_size the Linux kernel should gets passed
1954 the now "corrected" memory size and won't touch it either.
1955 This should work for arch/ppc and arch/powerpc. Only Linux
1956 board ports in arch/powerpc with bootwrapper support that
1957 recalculate the memory size from the SDRAM controller setup
1958 will have to get fixed in Linux additionally.
1960 This option can be used as a workaround for the 440EPx/GRx
1961 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1964 WARNING: Please make sure that this value is a multiple of
1965 the Linux page size (normally 4k). If this is not the case,
1966 then the end address of the Linux memory will be located at a
1967 non page size aligned address and this could cause major
1970 - CFG_TFTP_LOADADDR:
1971 Default load address for network file downloads
1973 - CFG_LOADS_BAUD_CHANGE:
1974 Enable temporary baudrate change while serial download
1977 Physical start address of SDRAM. _Must_ be 0 here.
1980 Physical start address of Motherboard I/O (if using a
1984 Physical start address of Flash memory.
1987 Physical start address of boot monitor code (set by
1988 make config files to be same as the text base address
1989 (TEXT_BASE) used when linking) - same as
1990 CFG_FLASH_BASE when booting from flash.
1993 Size of memory reserved for monitor code, used to
1994 determine _at_compile_time_ (!) if the environment is
1995 embedded within the U-Boot image, or in a separate
1999 Size of DRAM reserved for malloc() use.
2002 Normally compressed uImages are limited to an
2003 uncompressed size of 8 MBytes. If this is not enough,
2004 you can define CFG_BOOTM_LEN in your board config file
2005 to adjust this setting to your needs.
2008 Maximum size of memory mapped by the startup code of
2009 the Linux kernel; all data that must be processed by
2010 the Linux kernel (bd_info, boot arguments, FDT blob if
2011 used) must be put below this limit, unless "bootm_low"
2012 enviroment variable is defined and non-zero. In such case
2013 all data for the Linux kernel must be between "bootm_low"
2014 and "bootm_low" + CFG_BOOTMAPSZ.
2016 - CFG_MAX_FLASH_BANKS:
2017 Max number of Flash memory banks
2019 - CFG_MAX_FLASH_SECT:
2020 Max number of sectors on a Flash chip
2022 - CFG_FLASH_ERASE_TOUT:
2023 Timeout for Flash erase operations (in ms)
2025 - CFG_FLASH_WRITE_TOUT:
2026 Timeout for Flash write operations (in ms)
2028 - CFG_FLASH_LOCK_TOUT
2029 Timeout for Flash set sector lock bit operation (in ms)
2031 - CFG_FLASH_UNLOCK_TOUT
2032 Timeout for Flash clear lock bits operation (in ms)
2034 - CFG_FLASH_PROTECTION
2035 If defined, hardware flash sectors protection is used
2036 instead of U-Boot software protection.
2038 - CFG_DIRECT_FLASH_TFTP:
2040 Enable TFTP transfers directly to flash memory;
2041 without this option such a download has to be
2042 performed in two steps: (1) download to RAM, and (2)
2043 copy from RAM to flash.
2045 The two-step approach is usually more reliable, since
2046 you can check if the download worked before you erase
2047 the flash, but in some situations (when sytem RAM is
2048 too limited to allow for a tempory copy of the
2049 downloaded image) this option may be very useful.
2052 Define if the flash driver uses extra elements in the
2053 common flash structure for storing flash geometry.
2055 - CFG_FLASH_CFI_DRIVER
2056 This option also enables the building of the cfi_flash driver
2057 in the drivers directory
2059 - CFG_FLASH_USE_BUFFER_WRITE
2060 Use buffered writes to flash.
2062 - CONFIG_FLASH_SPANSION_S29WS_N
2063 s29ws-n MirrorBit flash has non-standard addresses for buffered
2066 - CFG_FLASH_QUIET_TEST
2067 If this option is defined, the common CFI flash doesn't
2068 print it's warning upon not recognized FLASH banks. This
2069 is useful, if some of the configured banks are only
2070 optionally available.
2072 - CONFIG_FLASH_SHOW_PROGRESS
2073 If defined (must be an integer), print out countdown
2074 digits and dots. Recommended value: 45 (9..1) for 80
2075 column displays, 15 (3..1) for 40 column displays.
2077 - CFG_RX_ETH_BUFFER:
2078 Defines the number of ethernet receive buffers. On some
2079 ethernet controllers it is recommended to set this value
2080 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2081 buffers can be full shortly after enabling the interface
2082 on high ethernet traffic.
2083 Defaults to 4 if not defined.
2085 The following definitions that deal with the placement and management
2086 of environment data (variable area); in general, we support the
2087 following configurations:
2089 - CFG_ENV_IS_IN_FLASH:
2091 Define this if the environment is in flash memory.
2093 a) The environment occupies one whole flash sector, which is
2094 "embedded" in the text segment with the U-Boot code. This
2095 happens usually with "bottom boot sector" or "top boot
2096 sector" type flash chips, which have several smaller
2097 sectors at the start or the end. For instance, such a
2098 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2099 such a case you would place the environment in one of the
2100 4 kB sectors - with U-Boot code before and after it. With
2101 "top boot sector" type flash chips, you would put the
2102 environment in one of the last sectors, leaving a gap
2103 between U-Boot and the environment.
2107 Offset of environment data (variable area) to the
2108 beginning of flash memory; for instance, with bottom boot
2109 type flash chips the second sector can be used: the offset
2110 for this sector is given here.
2112 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2116 This is just another way to specify the start address of
2117 the flash sector containing the environment (instead of
2120 - CFG_ENV_SECT_SIZE:
2122 Size of the sector containing the environment.
2125 b) Sometimes flash chips have few, equal sized, BIG sectors.
2126 In such a case you don't want to spend a whole sector for
2131 If you use this in combination with CFG_ENV_IS_IN_FLASH
2132 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2133 of this flash sector for the environment. This saves
2134 memory for the RAM copy of the environment.
2136 It may also save flash memory if you decide to use this
2137 when your environment is "embedded" within U-Boot code,
2138 since then the remainder of the flash sector could be used
2139 for U-Boot code. It should be pointed out that this is
2140 STRONGLY DISCOURAGED from a robustness point of view:
2141 updating the environment in flash makes it always
2142 necessary to erase the WHOLE sector. If something goes
2143 wrong before the contents has been restored from a copy in
2144 RAM, your target system will be dead.
2146 - CFG_ENV_ADDR_REDUND
2149 These settings describe a second storage area used to hold
2150 a redundand copy of the environment data, so that there is
2151 a valid backup copy in case there is a power failure during
2152 a "saveenv" operation.
2154 BE CAREFUL! Any changes to the flash layout, and some changes to the
2155 source code will make it necessary to adapt <board>/u-boot.lds*
2159 - CFG_ENV_IS_IN_NVRAM:
2161 Define this if you have some non-volatile memory device
2162 (NVRAM, battery buffered SRAM) which you want to use for the
2168 These two #defines are used to determin the memory area you
2169 want to use for environment. It is assumed that this memory
2170 can just be read and written to, without any special
2173 BE CAREFUL! The first access to the environment happens quite early
2174 in U-Boot initalization (when we try to get the setting of for the
2175 console baudrate). You *MUST* have mappend your NVRAM area then, or
2178 Please note that even with NVRAM we still use a copy of the
2179 environment in RAM: we could work on NVRAM directly, but we want to
2180 keep settings there always unmodified except somebody uses "saveenv"
2181 to save the current settings.
2184 - CFG_ENV_IS_IN_EEPROM:
2186 Use this if you have an EEPROM or similar serial access
2187 device and a driver for it.
2192 These two #defines specify the offset and size of the
2193 environment area within the total memory of your EEPROM.
2195 - CFG_I2C_EEPROM_ADDR:
2196 If defined, specified the chip address of the EEPROM device.
2197 The default address is zero.
2199 - CFG_EEPROM_PAGE_WRITE_BITS:
2200 If defined, the number of bits used to address bytes in a
2201 single page in the EEPROM device. A 64 byte page, for example
2202 would require six bits.
2204 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2205 If defined, the number of milliseconds to delay between
2206 page writes. The default is zero milliseconds.
2208 - CFG_I2C_EEPROM_ADDR_LEN:
2209 The length in bytes of the EEPROM memory array address. Note
2210 that this is NOT the chip address length!
2212 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2213 EEPROM chips that implement "address overflow" are ones
2214 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2215 address and the extra bits end up in the "chip address" bit
2216 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2219 Note that we consider the length of the address field to
2220 still be one byte because the extra address bits are hidden
2221 in the chip address.
2224 The size in bytes of the EEPROM device.
2227 - CFG_ENV_IS_IN_DATAFLASH:
2229 Define this if you have a DataFlash memory device which you
2230 want to use for the environment.
2236 These three #defines specify the offset and size of the
2237 environment area within the total memory of your DataFlash placed
2238 at the specified address.
2240 - CFG_ENV_IS_IN_NAND:
2242 Define this if you have a NAND device which you want to use
2243 for the environment.
2248 These two #defines specify the offset and size of the environment
2249 area within the first NAND device.
2251 - CFG_ENV_OFFSET_REDUND
2253 This setting describes a second storage area of CFG_ENV_SIZE
2254 size used to hold a redundant copy of the environment data,
2255 so that there is a valid backup copy in case there is a
2256 power failure during a "saveenv" operation.
2258 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2259 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2260 the NAND devices block size.
2262 - CFG_SPI_INIT_OFFSET
2264 Defines offset to the initial SPI buffer area in DPRAM. The
2265 area is used at an early stage (ROM part) if the environment
2266 is configured to reside in the SPI EEPROM: We need a 520 byte
2267 scratch DPRAM area. It is used between the two initialization
2268 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2269 to be a good choice since it makes it far enough from the
2270 start of the data area as well as from the stack pointer.
2272 Please note that the environment is read-only until the monitor
2273 has been relocated to RAM and a RAM copy of the environment has been
2274 created; also, when using EEPROM you will have to use getenv_r()
2275 until then to read environment variables.
2277 The environment is protected by a CRC32 checksum. Before the monitor
2278 is relocated into RAM, as a result of a bad CRC you will be working
2279 with the compiled-in default environment - *silently*!!! [This is
2280 necessary, because the first environment variable we need is the
2281 "baudrate" setting for the console - if we have a bad CRC, we don't
2282 have any device yet where we could complain.]
2284 Note: once the monitor has been relocated, then it will complain if
2285 the default environment is used; a new CRC is computed as soon as you
2286 use the "saveenv" command to store a valid environment.
2288 - CFG_FAULT_ECHO_LINK_DOWN:
2289 Echo the inverted Ethernet link state to the fault LED.
2291 Note: If this option is active, then CFG_FAULT_MII_ADDR
2292 also needs to be defined.
2294 - CFG_FAULT_MII_ADDR:
2295 MII address of the PHY to check for the Ethernet link state.
2297 - CFG_64BIT_VSPRINTF:
2298 Makes vsprintf (and all *printf functions) support printing
2299 of 64bit values by using the L quantifier
2301 - CFG_64BIT_STRTOUL:
2302 Adds simple_strtoull that returns a 64bit value
2304 Low Level (hardware related) configuration options:
2305 ---------------------------------------------------
2307 - CFG_CACHELINE_SIZE:
2308 Cache Line Size of the CPU.
2311 Default address of the IMMR after system reset.
2313 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2314 and RPXsuper) to be able to adjust the position of
2315 the IMMR register after a reset.
2317 - Floppy Disk Support:
2318 CFG_FDC_DRIVE_NUMBER
2320 the default drive number (default value 0)
2324 defines the spacing between fdc chipset registers
2329 defines the offset of register from address. It
2330 depends on which part of the data bus is connected to
2331 the fdc chipset. (default value 0)
2333 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2334 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2337 if CFG_FDC_HW_INIT is defined, then the function
2338 fdc_hw_init() is called at the beginning of the FDC
2339 setup. fdc_hw_init() must be provided by the board
2340 source code. It is used to make hardware dependant
2343 - CFG_IMMR: Physical address of the Internal Memory.
2344 DO NOT CHANGE unless you know exactly what you're
2345 doing! (11-4) [MPC8xx/82xx systems only]
2347 - CFG_INIT_RAM_ADDR:
2349 Start address of memory area that can be used for
2350 initial data and stack; please note that this must be
2351 writable memory that is working WITHOUT special
2352 initialization, i. e. you CANNOT use normal RAM which
2353 will become available only after programming the
2354 memory controller and running certain initialization
2357 U-Boot uses the following memory types:
2358 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2359 - MPC824X: data cache
2360 - PPC4xx: data cache
2362 - CFG_GBL_DATA_OFFSET:
2364 Offset of the initial data structure in the memory
2365 area defined by CFG_INIT_RAM_ADDR. Usually
2366 CFG_GBL_DATA_OFFSET is chosen such that the initial
2367 data is located at the end of the available space
2368 (sometimes written as (CFG_INIT_RAM_END -
2369 CFG_INIT_DATA_SIZE), and the initial stack is just
2370 below that area (growing from (CFG_INIT_RAM_ADDR +
2371 CFG_GBL_DATA_OFFSET) downward.
2374 On the MPC824X (or other systems that use the data
2375 cache for initial memory) the address chosen for
2376 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2377 point to an otherwise UNUSED address space between
2378 the top of RAM and the start of the PCI space.
2380 - CFG_SIUMCR: SIU Module Configuration (11-6)
2382 - CFG_SYPCR: System Protection Control (11-9)
2384 - CFG_TBSCR: Time Base Status and Control (11-26)
2386 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2388 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2390 - CFG_SCCR: System Clock and reset Control Register (15-27)
2392 - CFG_OR_TIMING_SDRAM:
2396 periodic timer for refresh
2398 - CFG_DER: Debug Event Register (37-47)
2400 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2401 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2402 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2404 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2406 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2407 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2408 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2409 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2411 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2412 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2413 Machine Mode Register and Memory Periodic Timer
2414 Prescaler definitions (SDRAM timing)
2416 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2417 enable I2C microcode relocation patch (MPC8xx);
2418 define relocation offset in DPRAM [DSP2]
2420 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2421 enable SMC microcode relocation patch (MPC8xx);
2422 define relocation offset in DPRAM [SMC1]
2424 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2425 enable SPI microcode relocation patch (MPC8xx);
2426 define relocation offset in DPRAM [SCC4]
2429 Use OSCM clock mode on MBX8xx board. Be careful,
2430 wrong setting might damage your board. Read
2431 doc/README.MBX before setting this variable!
2433 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2434 Offset of the bootmode word in DPRAM used by post
2435 (Power On Self Tests). This definition overrides
2436 #define'd default value in commproc.h resp.
2439 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2440 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2441 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2442 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2443 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2444 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2445 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2446 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2447 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2450 Get DDR timing information from an I2C EEPROM. Common
2451 with pluggable memory modules such as SODIMMs
2454 I2C address of the SPD EEPROM
2457 If SPD EEPROM is on an I2C bus other than the first
2458 one, specify here. Note that the value must resolve
2459 to something your driver can deal with.
2461 - CFG_83XX_DDR_USES_CS0
2462 Only for 83xx systems. If specified, then DDR should
2463 be configured using CS0 and CS1 instead of CS2 and CS3.
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 - CONFIG_ETHER_ON_FEC[12]
2470 Define to enable FEC[12] on a 8xx series processor.
2472 - CONFIG_FEC[12]_PHY
2473 Define to the hardcoded PHY address which corresponds
2474 to the given FEC; i. e.
2475 #define CONFIG_FEC1_PHY 4
2476 means that the PHY with address 4 is connected to FEC1
2478 When set to -1, means to probe for first available.
2480 - CONFIG_FEC[12]_PHY_NORXERR
2481 The PHY does not have a RXERR line (RMII only).
2482 (so program the FEC to ignore it).
2485 Enable RMII mode for all FECs.
2486 Note that this is a global option, we can't
2487 have one FEC in standard MII mode and another in RMII mode.
2489 - CONFIG_CRC32_VERIFY
2490 Add a verify option to the crc32 command.
2493 => crc32 -v <address> <count> <crc32>
2495 Where address/count indicate a memory area
2496 and crc32 is the correct crc32 which the
2500 Add the "loopw" memory command. This only takes effect if
2501 the memory commands are activated globally (CONFIG_CMD_MEM).
2504 Add the "mdc" and "mwc" memory commands. These are cyclic
2509 This command will print 4 bytes (10,11,12,13) each 500 ms.
2511 => mwc.l 100 12345678 10
2512 This command will write 12345678 to address 100 all 10 ms.
2514 This only takes effect if the memory commands are activated
2515 globally (CONFIG_CMD_MEM).
2517 - CONFIG_SKIP_LOWLEVEL_INIT
2518 - CONFIG_SKIP_RELOCATE_UBOOT
2520 [ARM only] If these variables are defined, then
2521 certain low level initializations (like setting up
2522 the memory controller) are omitted and/or U-Boot does
2523 not relocate itself into RAM.
2524 Normally these variables MUST NOT be defined. The
2525 only exception is when U-Boot is loaded (to RAM) by
2526 some other boot loader or by a debugger which
2527 performs these intializations itself.
2530 Building the Software:
2531 ======================
2533 Building U-Boot has been tested in several native build environments
2534 and in many different cross environments. Of course we cannot support
2535 all possibly existing versions of cross development tools in all
2536 (potentially obsolete) versions. In case of tool chain problems we
2537 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2538 which is extensively used to build and test U-Boot.
2540 If you are not using a native environment, it is assumed that you
2541 have GNU cross compiling tools available in your path. In this case,
2542 you must set the environment variable CROSS_COMPILE in your shell.
2543 Note that no changes to the Makefile or any other source files are
2544 necessary. For example using the ELDK on a 4xx CPU, please enter:
2546 $ CROSS_COMPILE=ppc_4xx-
2547 $ export CROSS_COMPILE
2549 U-Boot is intended to be simple to build. After installing the
2550 sources you must configure U-Boot for one specific board type. This
2555 where "NAME_config" is the name of one of the existing configu-
2556 rations; see the main Makefile for supported names.
2558 Note: for some board special configuration names may exist; check if
2559 additional information is available from the board vendor; for
2560 instance, the TQM823L systems are available without (standard)
2561 or with LCD support. You can select such additional "features"
2562 when chosing the configuration, i. e.
2565 - will configure for a plain TQM823L, i. e. no LCD support
2567 make TQM823L_LCD_config
2568 - will configure for a TQM823L with U-Boot console on LCD
2573 Finally, type "make all", and you should get some working U-Boot
2574 images ready for download to / installation on your system:
2576 - "u-boot.bin" is a raw binary image
2577 - "u-boot" is an image in ELF binary format
2578 - "u-boot.srec" is in Motorola S-Record format
2580 By default the build is performed locally and the objects are saved
2581 in the source directory. One of the two methods can be used to change
2582 this behavior and build U-Boot to some external directory:
2584 1. Add O= to the make command line invocations:
2586 make O=/tmp/build distclean
2587 make O=/tmp/build NAME_config
2588 make O=/tmp/build all
2590 2. Set environment variable BUILD_DIR to point to the desired location:
2592 export BUILD_DIR=/tmp/build
2597 Note that the command line "O=" setting overrides the BUILD_DIR environment
2601 Please be aware that the Makefiles assume you are using GNU make, so
2602 for instance on NetBSD you might need to use "gmake" instead of
2606 If the system board that you have is not listed, then you will need
2607 to port U-Boot to your hardware platform. To do this, follow these
2610 1. Add a new configuration option for your board to the toplevel
2611 "Makefile" and to the "MAKEALL" script, using the existing
2612 entries as examples. Note that here and at many other places
2613 boards and other names are listed in alphabetical sort order. Please
2615 2. Create a new directory to hold your board specific code. Add any
2616 files you need. In your board directory, you will need at least
2617 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2618 3. Create a new configuration file "include/configs/<board>.h" for
2620 3. If you're porting U-Boot to a new CPU, then also create a new
2621 directory to hold your CPU specific code. Add any files you need.
2622 4. Run "make <board>_config" with your new name.
2623 5. Type "make", and you should get a working "u-boot.srec" file
2624 to be installed on your target system.
2625 6. Debug and solve any problems that might arise.
2626 [Of course, this last step is much harder than it sounds.]
2629 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2630 ==============================================================
2632 If you have modified U-Boot sources (for instance added a new board
2633 or support for new devices, a new CPU, etc.) you are expected to
2634 provide feedback to the other developers. The feedback normally takes
2635 the form of a "patch", i. e. a context diff against a certain (latest
2636 official or latest in the git repository) version of U-Boot sources.
2638 But before you submit such a patch, please verify that your modifi-
2639 cation did not break existing code. At least make sure that *ALL* of
2640 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2641 just run the "MAKEALL" script, which will configure and build U-Boot
2642 for ALL supported system. Be warned, this will take a while. You can
2643 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2644 environment variable to the script, i. e. to use the ELDK cross tools
2647 CROSS_COMPILE=ppc_8xx- MAKEALL
2649 or to build on a native PowerPC system you can type
2651 CROSS_COMPILE=' ' MAKEALL
2653 When using the MAKEALL script, the default behaviour is to build
2654 U-Boot in the source directory. This location can be changed by
2655 setting the BUILD_DIR environment variable. Also, for each target
2656 built, the MAKEALL script saves two log files (<target>.ERR and
2657 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2658 location can be changed by setting the MAKEALL_LOGDIR environment
2659 variable. For example:
2661 export BUILD_DIR=/tmp/build
2662 export MAKEALL_LOGDIR=/tmp/log
2663 CROSS_COMPILE=ppc_8xx- MAKEALL
2665 With the above settings build objects are saved in the /tmp/build,
2666 log files are saved in the /tmp/log and the source tree remains clean
2667 during the whole build process.
2670 See also "U-Boot Porting Guide" below.
2673 Monitor Commands - Overview:
2674 ============================
2676 go - start application at address 'addr'
2677 run - run commands in an environment variable
2678 bootm - boot application image from memory
2679 bootp - boot image via network using BootP/TFTP protocol
2680 tftpboot- boot image via network using TFTP protocol
2681 and env variables "ipaddr" and "serverip"
2682 (and eventually "gatewayip")
2683 rarpboot- boot image via network using RARP/TFTP protocol
2684 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2685 loads - load S-Record file over serial line
2686 loadb - load binary file over serial line (kermit mode)
2688 mm - memory modify (auto-incrementing)
2689 nm - memory modify (constant address)
2690 mw - memory write (fill)
2692 cmp - memory compare
2693 crc32 - checksum calculation
2694 imd - i2c memory display
2695 imm - i2c memory modify (auto-incrementing)
2696 inm - i2c memory modify (constant address)
2697 imw - i2c memory write (fill)
2698 icrc32 - i2c checksum calculation
2699 iprobe - probe to discover valid I2C chip addresses
2700 iloop - infinite loop on address range
2701 isdram - print SDRAM configuration information
2702 sspi - SPI utility commands
2703 base - print or set address offset
2704 printenv- print environment variables
2705 setenv - set environment variables
2706 saveenv - save environment variables to persistent storage
2707 protect - enable or disable FLASH write protection
2708 erase - erase FLASH memory
2709 flinfo - print FLASH memory information
2710 bdinfo - print Board Info structure
2711 iminfo - print header information for application image
2712 coninfo - print console devices and informations
2713 ide - IDE sub-system
2714 loop - infinite loop on address range
2715 loopw - infinite write loop on address range
2716 mtest - simple RAM test
2717 icache - enable or disable instruction cache
2718 dcache - enable or disable data cache
2719 reset - Perform RESET of the CPU
2720 echo - echo args to console
2721 version - print monitor version
2722 help - print online help
2723 ? - alias for 'help'
2726 Monitor Commands - Detailed Description:
2727 ========================================
2731 For now: just type "help <command>".
2734 Environment Variables:
2735 ======================
2737 U-Boot supports user configuration using Environment Variables which
2738 can be made persistent by saving to Flash memory.
2740 Environment Variables are set using "setenv", printed using
2741 "printenv", and saved to Flash using "saveenv". Using "setenv"
2742 without a value can be used to delete a variable from the
2743 environment. As long as you don't save the environment you are
2744 working with an in-memory copy. In case the Flash area containing the
2745 environment is erased by accident, a default environment is provided.
2747 Some configuration options can be set using Environment Variables:
2749 baudrate - see CONFIG_BAUDRATE
2751 bootdelay - see CONFIG_BOOTDELAY
2753 bootcmd - see CONFIG_BOOTCOMMAND
2755 bootargs - Boot arguments when booting an RTOS image
2757 bootfile - Name of the image to load with TFTP
2759 bootm_low - Memory range available for image processing in the bootm
2760 command can be restricted. This variable is given as
2761 a hexadecimal number and defines lowest address allowed
2762 for use by the bootm command. See also "bootm_size"
2763 environment variable. Address defined by "bootm_low" is
2764 also the base of the initial memory mapping for the Linux
2765 kernel -- see the descripton of CFG_BOOTMAPSZ.
2767 bootm_size - Memory range available for image processing in the bootm
2768 command can be restricted. This variable is given as
2769 a hexadecimal number and defines the size of the region
2770 allowed for use by the bootm command. See also "bootm_low"
2771 environment variable.
2773 autoload - if set to "no" (any string beginning with 'n'),
2774 "bootp" will just load perform a lookup of the
2775 configuration from the BOOTP server, but not try to
2776 load any image using TFTP
2778 autoscript - if set to "yes" commands like "loadb", "loady",
2779 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2780 to automatically run script images (by internally
2781 calling "autoscript").
2783 autoscript_uname - if script image is in a format (FIT) this
2784 variable is used to get script subimage unit name.
2786 autostart - if set to "yes", an image loaded using the "bootp",
2787 "rarpboot", "tftpboot" or "diskboot" commands will
2788 be automatically started (by internally calling
2791 If set to "no", a standalone image passed to the
2792 "bootm" command will be copied to the load address
2793 (and eventually uncompressed), but NOT be started.
2794 This can be used to load and uncompress arbitrary
2797 i2cfast - (PPC405GP|PPC405EP only)
2798 if set to 'y' configures Linux I2C driver for fast
2799 mode (400kHZ). This environment variable is used in
2800 initialization code. So, for changes to be effective
2801 it must be saved and board must be reset.
2803 initrd_high - restrict positioning of initrd images:
2804 If this variable is not set, initrd images will be
2805 copied to the highest possible address in RAM; this
2806 is usually what you want since it allows for
2807 maximum initrd size. If for some reason you want to
2808 make sure that the initrd image is loaded below the
2809 CFG_BOOTMAPSZ limit, you can set this environment
2810 variable to a value of "no" or "off" or "0".
2811 Alternatively, you can set it to a maximum upper
2812 address to use (U-Boot will still check that it
2813 does not overwrite the U-Boot stack and data).
2815 For instance, when you have a system with 16 MB
2816 RAM, and want to reserve 4 MB from use by Linux,
2817 you can do this by adding "mem=12M" to the value of
2818 the "bootargs" variable. However, now you must make
2819 sure that the initrd image is placed in the first
2820 12 MB as well - this can be done with
2822 setenv initrd_high 00c00000
2824 If you set initrd_high to 0xFFFFFFFF, this is an
2825 indication to U-Boot that all addresses are legal
2826 for the Linux kernel, including addresses in flash
2827 memory. In this case U-Boot will NOT COPY the
2828 ramdisk at all. This may be useful to reduce the
2829 boot time on your system, but requires that this
2830 feature is supported by your Linux kernel.
2832 ipaddr - IP address; needed for tftpboot command
2834 loadaddr - Default load address for commands like "bootp",
2835 "rarpboot", "tftpboot", "loadb" or "diskboot"
2837 loads_echo - see CONFIG_LOADS_ECHO
2839 serverip - TFTP server IP address; needed for tftpboot command
2841 bootretry - see CONFIG_BOOT_RETRY_TIME
2843 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2845 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2847 ethprime - When CONFIG_NET_MULTI is enabled controls which
2848 interface is used first.
2850 ethact - When CONFIG_NET_MULTI is enabled controls which
2851 interface is currently active. For example you
2852 can do the following
2854 => setenv ethact FEC ETHERNET
2855 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2856 => setenv ethact SCC ETHERNET
2857 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2859 ethrotate - When set to "no" U-Boot does not go through all
2860 available network interfaces.
2861 It just stays at the currently selected interface.
2863 netretry - When set to "no" each network operation will
2864 either succeed or fail without retrying.
2865 When set to "once" the network operation will
2866 fail when all the available network interfaces
2867 are tried once without success.
2868 Useful on scripts which control the retry operation
2871 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2872 if set load address for the npe microcode
2874 tftpsrcport - If this is set, the value is used for TFTP's
2877 tftpdstport - If this is set, the value is used for TFTP's UDP
2878 destination port instead of the Well Know Port 69.
2880 vlan - When set to a value < 4095 the traffic over
2881 ethernet is encapsulated/received over 802.1q
2884 The following environment variables may be used and automatically
2885 updated by the network boot commands ("bootp" and "rarpboot"),
2886 depending the information provided by your boot server:
2888 bootfile - see above
2889 dnsip - IP address of your Domain Name Server
2890 dnsip2 - IP address of your secondary Domain Name Server
2891 gatewayip - IP address of the Gateway (Router) to use
2892 hostname - Target hostname
2894 netmask - Subnet Mask
2895 rootpath - Pathname of the root filesystem on the NFS server
2896 serverip - see above
2899 There are two special Environment Variables:
2901 serial# - contains hardware identification information such
2902 as type string and/or serial number
2903 ethaddr - Ethernet address
2905 These variables can be set only once (usually during manufacturing of
2906 the board). U-Boot refuses to delete or overwrite these variables
2907 once they have been set once.
2910 Further special Environment Variables:
2912 ver - Contains the U-Boot version string as printed
2913 with the "version" command. This variable is
2914 readonly (see CONFIG_VERSION_VARIABLE).
2917 Please note that changes to some configuration parameters may take
2918 only effect after the next boot (yes, that's just like Windoze :-).
2921 Command Line Parsing:
2922 =====================
2924 There are two different command line parsers available with U-Boot:
2925 the old "simple" one, and the much more powerful "hush" shell:
2927 Old, simple command line parser:
2928 --------------------------------
2930 - supports environment variables (through setenv / saveenv commands)
2931 - several commands on one line, separated by ';'
2932 - variable substitution using "... ${name} ..." syntax
2933 - special characters ('$', ';') can be escaped by prefixing with '\',
2935 setenv bootcmd bootm \${address}
2936 - You can also escape text by enclosing in single apostrophes, for example:
2937 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2942 - similar to Bourne shell, with control structures like
2943 if...then...else...fi, for...do...done; while...do...done,
2944 until...do...done, ...
2945 - supports environment ("global") variables (through setenv / saveenv
2946 commands) and local shell variables (through standard shell syntax
2947 "name=value"); only environment variables can be used with "run"
2953 (1) If a command line (or an environment variable executed by a "run"
2954 command) contains several commands separated by semicolon, and
2955 one of these commands fails, then the remaining commands will be
2958 (2) If you execute several variables with one call to run (i. e.
2959 calling run with a list af variables as arguments), any failing
2960 command will cause "run" to terminate, i. e. the remaining
2961 variables are not executed.
2963 Note for Redundant Ethernet Interfaces:
2964 =======================================
2966 Some boards come with redundant ethernet interfaces; U-Boot supports
2967 such configurations and is capable of automatic selection of a
2968 "working" interface when needed. MAC assignment works as follows:
2970 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2971 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2972 "eth1addr" (=>eth1), "eth2addr", ...
2974 If the network interface stores some valid MAC address (for instance
2975 in SROM), this is used as default address if there is NO correspon-
2976 ding setting in the environment; if the corresponding environment
2977 variable is set, this overrides the settings in the card; that means:
2979 o If the SROM has a valid MAC address, and there is no address in the
2980 environment, the SROM's address is used.
2982 o If there is no valid address in the SROM, and a definition in the
2983 environment exists, then the value from the environment variable is
2986 o If both the SROM and the environment contain a MAC address, and
2987 both addresses are the same, this MAC address is used.
2989 o If both the SROM and the environment contain a MAC address, and the
2990 addresses differ, the value from the environment is used and a
2993 o If neither SROM nor the environment contain a MAC address, an error
3000 U-Boot is capable of booting (and performing other auxiliary operations on)
3001 images in two formats:
3003 New uImage format (FIT)
3004 -----------------------
3006 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3007 to Flattened Device Tree). It allows the use of images with multiple
3008 components (several kernels, ramdisks, etc.), with contents protected by
3009 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3015 Old image format is based on binary files which can be basically anything,
3016 preceded by a special header; see the definitions in include/image.h for
3017 details; basically, the header defines the following image properties:
3019 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3020 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3021 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3022 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3023 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3024 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3025 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3026 * Compression Type (uncompressed, gzip, bzip2)
3032 The header is marked by a special Magic Number, and both the header
3033 and the data portions of the image are secured against corruption by
3040 Although U-Boot should support any OS or standalone application
3041 easily, the main focus has always been on Linux during the design of
3044 U-Boot includes many features that so far have been part of some
3045 special "boot loader" code within the Linux kernel. Also, any
3046 "initrd" images to be used are no longer part of one big Linux image;
3047 instead, kernel and "initrd" are separate images. This implementation
3048 serves several purposes:
3050 - the same features can be used for other OS or standalone
3051 applications (for instance: using compressed images to reduce the
3052 Flash memory footprint)
3054 - it becomes much easier to port new Linux kernel versions because
3055 lots of low-level, hardware dependent stuff are done by U-Boot
3057 - the same Linux kernel image can now be used with different "initrd"
3058 images; of course this also means that different kernel images can
3059 be run with the same "initrd". This makes testing easier (you don't
3060 have to build a new "zImage.initrd" Linux image when you just
3061 change a file in your "initrd"). Also, a field-upgrade of the
3062 software is easier now.
3068 Porting Linux to U-Boot based systems:
3069 ---------------------------------------
3071 U-Boot cannot save you from doing all the necessary modifications to
3072 configure the Linux device drivers for use with your target hardware
3073 (no, we don't intend to provide a full virtual machine interface to
3076 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3078 Just make sure your machine specific header file (for instance
3079 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3080 Information structure as we define in include/u-boot.h, and make
3081 sure that your definition of IMAP_ADDR uses the same value as your
3082 U-Boot configuration in CFG_IMMR.
3085 Configuring the Linux kernel:
3086 -----------------------------
3088 No specific requirements for U-Boot. Make sure you have some root
3089 device (initial ramdisk, NFS) for your target system.
3092 Building a Linux Image:
3093 -----------------------
3095 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3096 not used. If you use recent kernel source, a new build target
3097 "uImage" will exist which automatically builds an image usable by
3098 U-Boot. Most older kernels also have support for a "pImage" target,
3099 which was introduced for our predecessor project PPCBoot and uses a
3100 100% compatible format.
3109 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3110 encapsulate a compressed Linux kernel image with header information,
3111 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3113 * build a standard "vmlinux" kernel image (in ELF binary format):
3115 * convert the kernel into a raw binary image:
3117 ${CROSS_COMPILE}-objcopy -O binary \
3118 -R .note -R .comment \
3119 -S vmlinux linux.bin
3121 * compress the binary image:
3125 * package compressed binary image for U-Boot:
3127 mkimage -A ppc -O linux -T kernel -C gzip \
3128 -a 0 -e 0 -n "Linux Kernel Image" \
3129 -d linux.bin.gz uImage
3132 The "mkimage" tool can also be used to create ramdisk images for use
3133 with U-Boot, either separated from the Linux kernel image, or
3134 combined into one file. "mkimage" encapsulates the images with a 64
3135 byte header containing information about target architecture,
3136 operating system, image type, compression method, entry points, time
3137 stamp, CRC32 checksums, etc.
3139 "mkimage" can be called in two ways: to verify existing images and
3140 print the header information, or to build new images.
3142 In the first form (with "-l" option) mkimage lists the information
3143 contained in the header of an existing U-Boot image; this includes
3144 checksum verification:
3146 tools/mkimage -l image
3147 -l ==> list image header information
3149 The second form (with "-d" option) is used to build a U-Boot image
3150 from a "data file" which is used as image payload:
3152 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3153 -n name -d data_file image
3154 -A ==> set architecture to 'arch'
3155 -O ==> set operating system to 'os'
3156 -T ==> set image type to 'type'
3157 -C ==> set compression type 'comp'
3158 -a ==> set load address to 'addr' (hex)
3159 -e ==> set entry point to 'ep' (hex)
3160 -n ==> set image name to 'name'
3161 -d ==> use image data from 'datafile'
3163 Right now, all Linux kernels for PowerPC systems use the same load
3164 address (0x00000000), but the entry point address depends on the
3167 - 2.2.x kernels have the entry point at 0x0000000C,
3168 - 2.3.x and later kernels have the entry point at 0x00000000.
3170 So a typical call to build a U-Boot image would read:
3172 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3173 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3174 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3175 > examples/uImage.TQM850L
3176 Image Name: 2.4.4 kernel for TQM850L
3177 Created: Wed Jul 19 02:34:59 2000
3178 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3179 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3180 Load Address: 0x00000000
3181 Entry Point: 0x00000000
3183 To verify the contents of the image (or check for corruption):
3185 -> tools/mkimage -l examples/uImage.TQM850L
3186 Image Name: 2.4.4 kernel for TQM850L
3187 Created: Wed Jul 19 02:34:59 2000
3188 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3189 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3190 Load Address: 0x00000000
3191 Entry Point: 0x00000000
3193 NOTE: for embedded systems where boot time is critical you can trade
3194 speed for memory and install an UNCOMPRESSED image instead: this
3195 needs more space in Flash, but boots much faster since it does not
3196 need to be uncompressed:
3198 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3199 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3200 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3201 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3202 > examples/uImage.TQM850L-uncompressed
3203 Image Name: 2.4.4 kernel for TQM850L
3204 Created: Wed Jul 19 02:34:59 2000
3205 Image Type: PowerPC Linux Kernel Image (uncompressed)
3206 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3207 Load Address: 0x00000000
3208 Entry Point: 0x00000000
3211 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3212 when your kernel is intended to use an initial ramdisk:
3214 -> tools/mkimage -n 'Simple Ramdisk Image' \
3215 > -A ppc -O linux -T ramdisk -C gzip \
3216 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3217 Image Name: Simple Ramdisk Image
3218 Created: Wed Jan 12 14:01:50 2000
3219 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3220 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3221 Load Address: 0x00000000
3222 Entry Point: 0x00000000
3225 Installing a Linux Image:
3226 -------------------------
3228 To downloading a U-Boot image over the serial (console) interface,
3229 you must convert the image to S-Record format:
3231 objcopy -I binary -O srec examples/image examples/image.srec
3233 The 'objcopy' does not understand the information in the U-Boot
3234 image header, so the resulting S-Record file will be relative to
3235 address 0x00000000. To load it to a given address, you need to
3236 specify the target address as 'offset' parameter with the 'loads'
3239 Example: install the image to address 0x40100000 (which on the
3240 TQM8xxL is in the first Flash bank):
3242 => erase 40100000 401FFFFF
3248 ## Ready for S-Record download ...
3249 ~>examples/image.srec
3250 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3252 15989 15990 15991 15992
3253 [file transfer complete]
3255 ## Start Addr = 0x00000000
3258 You can check the success of the download using the 'iminfo' command;
3259 this includes a checksum verification so you can be sure no data
3260 corruption happened:
3264 ## Checking Image at 40100000 ...
3265 Image Name: 2.2.13 for initrd on TQM850L
3266 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3267 Data Size: 335725 Bytes = 327 kB = 0 MB
3268 Load Address: 00000000
3269 Entry Point: 0000000c
3270 Verifying Checksum ... OK
3276 The "bootm" command is used to boot an application that is stored in
3277 memory (RAM or Flash). In case of a Linux kernel image, the contents
3278 of the "bootargs" environment variable is passed to the kernel as
3279 parameters. You can check and modify this variable using the
3280 "printenv" and "setenv" commands:
3283 => printenv bootargs
3284 bootargs=root=/dev/ram
3286 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3288 => printenv bootargs
3289 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3292 ## Booting Linux kernel at 40020000 ...
3293 Image Name: 2.2.13 for NFS on TQM850L
3294 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3295 Data Size: 381681 Bytes = 372 kB = 0 MB
3296 Load Address: 00000000
3297 Entry Point: 0000000c
3298 Verifying Checksum ... OK
3299 Uncompressing Kernel Image ... OK
3300 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
3301 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3302 time_init: decrementer frequency = 187500000/60
3303 Calibrating delay loop... 49.77 BogoMIPS
3304 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3307 If you want to boot a Linux kernel with initial ram disk, you pass
3308 the memory addresses of both the kernel and the initrd image (PPBCOOT
3309 format!) to the "bootm" command:
3311 => imi 40100000 40200000
3313 ## Checking Image at 40100000 ...
3314 Image Name: 2.2.13 for initrd on TQM850L
3315 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3316 Data Size: 335725 Bytes = 327 kB = 0 MB
3317 Load Address: 00000000
3318 Entry Point: 0000000c
3319 Verifying Checksum ... OK
3321 ## Checking Image at 40200000 ...
3322 Image Name: Simple Ramdisk Image
3323 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3324 Data Size: 566530 Bytes = 553 kB = 0 MB
3325 Load Address: 00000000
3326 Entry Point: 00000000
3327 Verifying Checksum ... OK
3329 => bootm 40100000 40200000
3330 ## Booting Linux kernel at 40100000 ...
3331 Image Name: 2.2.13 for initrd on TQM850L
3332 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3333 Data Size: 335725 Bytes = 327 kB = 0 MB
3334 Load Address: 00000000
3335 Entry Point: 0000000c
3336 Verifying Checksum ... OK
3337 Uncompressing Kernel Image ... OK
3338 ## Loading RAMDisk Image at 40200000 ...
3339 Image Name: Simple Ramdisk Image
3340 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3341 Data Size: 566530 Bytes = 553 kB = 0 MB
3342 Load Address: 00000000
3343 Entry Point: 00000000
3344 Verifying Checksum ... OK
3345 Loading Ramdisk ... OK
3346 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
3347 Boot arguments: root=/dev/ram
3348 time_init: decrementer frequency = 187500000/60
3349 Calibrating delay loop... 49.77 BogoMIPS
3351 RAMDISK: Compressed image found at block 0
3352 VFS: Mounted root (ext2 filesystem).
3356 Boot Linux and pass a flat device tree:
3359 First, U-Boot must be compiled with the appropriate defines. See the section
3360 titled "Linux Kernel Interface" above for a more in depth explanation. The
3361 following is an example of how to start a kernel and pass an updated
3367 oft=oftrees/mpc8540ads.dtb
3368 => tftp $oftaddr $oft
3369 Speed: 1000, full duplex
3371 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3372 Filename 'oftrees/mpc8540ads.dtb'.
3373 Load address: 0x300000
3376 Bytes transferred = 4106 (100a hex)
3377 => tftp $loadaddr $bootfile
3378 Speed: 1000, full duplex
3380 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3382 Load address: 0x200000
3383 Loading:############
3385 Bytes transferred = 1029407 (fb51f hex)
3390 => bootm $loadaddr - $oftaddr
3391 ## Booting image at 00200000 ...
3392 Image Name: Linux-2.6.17-dirty
3393 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3394 Data Size: 1029343 Bytes = 1005.2 kB
3395 Load Address: 00000000
3396 Entry Point: 00000000
3397 Verifying Checksum ... OK
3398 Uncompressing Kernel Image ... OK
3399 Booting using flat device tree at 0x300000
3400 Using MPC85xx ADS machine description
3401 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3405 More About U-Boot Image Types:
3406 ------------------------------
3408 U-Boot supports the following image types:
3410 "Standalone Programs" are directly runnable in the environment
3411 provided by U-Boot; it is expected that (if they behave
3412 well) you can continue to work in U-Boot after return from
3413 the Standalone Program.
3414 "OS Kernel Images" are usually images of some Embedded OS which
3415 will take over control completely. Usually these programs
3416 will install their own set of exception handlers, device
3417 drivers, set up the MMU, etc. - this means, that you cannot
3418 expect to re-enter U-Boot except by resetting the CPU.
3419 "RAMDisk Images" are more or less just data blocks, and their
3420 parameters (address, size) are passed to an OS kernel that is
3422 "Multi-File Images" contain several images, typically an OS
3423 (Linux) kernel image and one or more data images like
3424 RAMDisks. This construct is useful for instance when you want
3425 to boot over the network using BOOTP etc., where the boot
3426 server provides just a single image file, but you want to get
3427 for instance an OS kernel and a RAMDisk image.
3429 "Multi-File Images" start with a list of image sizes, each
3430 image size (in bytes) specified by an "uint32_t" in network
3431 byte order. This list is terminated by an "(uint32_t)0".
3432 Immediately after the terminating 0 follow the images, one by
3433 one, all aligned on "uint32_t" boundaries (size rounded up to
3434 a multiple of 4 bytes).
3436 "Firmware Images" are binary images containing firmware (like
3437 U-Boot or FPGA images) which usually will be programmed to
3440 "Script files" are command sequences that will be executed by
3441 U-Boot's command interpreter; this feature is especially
3442 useful when you configure U-Boot to use a real shell (hush)
3443 as command interpreter.
3449 One of the features of U-Boot is that you can dynamically load and
3450 run "standalone" applications, which can use some resources of
3451 U-Boot like console I/O functions or interrupt services.
3453 Two simple examples are included with the sources:
3458 'examples/hello_world.c' contains a small "Hello World" Demo
3459 application; it is automatically compiled when you build U-Boot.
3460 It's configured to run at address 0x00040004, so you can play with it
3464 ## Ready for S-Record download ...
3465 ~>examples/hello_world.srec
3466 1 2 3 4 5 6 7 8 9 10 11 ...
3467 [file transfer complete]
3469 ## Start Addr = 0x00040004
3471 => go 40004 Hello World! This is a test.
3472 ## Starting application at 0x00040004 ...
3483 Hit any key to exit ...
3485 ## Application terminated, rc = 0x0
3487 Another example, which demonstrates how to register a CPM interrupt
3488 handler with the U-Boot code, can be found in 'examples/timer.c'.
3489 Here, a CPM timer is set up to generate an interrupt every second.
3490 The interrupt service routine is trivial, just printing a '.'
3491 character, but this is just a demo program. The application can be
3492 controlled by the following keys:
3494 ? - print current values og the CPM Timer registers
3495 b - enable interrupts and start timer
3496 e - stop timer and disable interrupts
3497 q - quit application
3500 ## Ready for S-Record download ...
3501 ~>examples/timer.srec
3502 1 2 3 4 5 6 7 8 9 10 11 ...
3503 [file transfer complete]
3505 ## Start Addr = 0x00040004
3508 ## Starting application at 0x00040004 ...
3511 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3514 [q, b, e, ?] Set interval 1000000 us
3517 [q, b, e, ?] ........
3518 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3521 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3524 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3527 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3529 [q, b, e, ?] ...Stopping timer
3531 [q, b, e, ?] ## Application terminated, rc = 0x0
3537 Over time, many people have reported problems when trying to use the
3538 "minicom" terminal emulation program for serial download. I (wd)
3539 consider minicom to be broken, and recommend not to use it. Under
3540 Unix, I recommend to use C-Kermit for general purpose use (and
3541 especially for kermit binary protocol download ("loadb" command), and
3542 use "cu" for S-Record download ("loads" command).
3544 Nevertheless, if you absolutely want to use it try adding this
3545 configuration to your "File transfer protocols" section:
3547 Name Program Name U/D FullScr IO-Red. Multi
3548 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3549 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3555 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3556 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3558 Building requires a cross environment; it is known to work on
3559 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3560 need gmake since the Makefiles are not compatible with BSD make).
3561 Note that the cross-powerpc package does not install include files;
3562 attempting to build U-Boot will fail because <machine/ansi.h> is
3563 missing. This file has to be installed and patched manually:
3565 # cd /usr/pkg/cross/powerpc-netbsd/include
3567 # ln -s powerpc machine
3568 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3569 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3571 Native builds *don't* work due to incompatibilities between native
3572 and U-Boot include files.
3574 Booting assumes that (the first part of) the image booted is a
3575 stage-2 loader which in turn loads and then invokes the kernel
3576 proper. Loader sources will eventually appear in the NetBSD source
3577 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3578 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3581 Implementation Internals:
3582 =========================
3584 The following is not intended to be a complete description of every
3585 implementation detail. However, it should help to understand the
3586 inner workings of U-Boot and make it easier to port it to custom
3590 Initial Stack, Global Data:
3591 ---------------------------
3593 The implementation of U-Boot is complicated by the fact that U-Boot
3594 starts running out of ROM (flash memory), usually without access to
3595 system RAM (because the memory controller is not initialized yet).
3596 This means that we don't have writable Data or BSS segments, and BSS
3597 is not initialized as zero. To be able to get a C environment working
3598 at all, we have to allocate at least a minimal stack. Implementation
3599 options for this are defined and restricted by the CPU used: Some CPU
3600 models provide on-chip memory (like the IMMR area on MPC8xx and
3601 MPC826x processors), on others (parts of) the data cache can be
3602 locked as (mis-) used as memory, etc.
3604 Chris Hallinan posted a good summary of these issues to the
3605 u-boot-users mailing list:
3607 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3608 From: "Chris Hallinan" <clh@net1plus.com>
3609 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3612 Correct me if I'm wrong, folks, but the way I understand it
3613 is this: Using DCACHE as initial RAM for Stack, etc, does not
3614 require any physical RAM backing up the cache. The cleverness
3615 is that the cache is being used as a temporary supply of
3616 necessary storage before the SDRAM controller is setup. It's
3617 beyond the scope of this list to expain the details, but you
3618 can see how this works by studying the cache architecture and
3619 operation in the architecture and processor-specific manuals.
3621 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3622 is another option for the system designer to use as an
3623 initial stack/ram area prior to SDRAM being available. Either
3624 option should work for you. Using CS 4 should be fine if your
3625 board designers haven't used it for something that would
3626 cause you grief during the initial boot! It is frequently not
3629 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3630 with your processor/board/system design. The default value
3631 you will find in any recent u-boot distribution in
3632 walnut.h should work for you. I'd set it to a value larger
3633 than your SDRAM module. If you have a 64MB SDRAM module, set
3634 it above 400_0000. Just make sure your board has no resources
3635 that are supposed to respond to that address! That code in
3636 start.S has been around a while and should work as is when
3637 you get the config right.
3642 It is essential to remember this, since it has some impact on the C
3643 code for the initialization procedures:
3645 * Initialized global data (data segment) is read-only. Do not attempt
3648 * Do not use any unitialized global data (or implicitely initialized
3649 as zero data - BSS segment) at all - this is undefined, initiali-
3650 zation is performed later (when relocating to RAM).
3652 * Stack space is very limited. Avoid big data buffers or things like
3655 Having only the stack as writable memory limits means we cannot use
3656 normal global data to share information beween the code. But it
3657 turned out that the implementation of U-Boot can be greatly
3658 simplified by making a global data structure (gd_t) available to all
3659 functions. We could pass a pointer to this data as argument to _all_
3660 functions, but this would bloat the code. Instead we use a feature of
3661 the GCC compiler (Global Register Variables) to share the data: we
3662 place a pointer (gd) to the global data into a register which we
3663 reserve for this purpose.
3665 When choosing a register for such a purpose we are restricted by the
3666 relevant (E)ABI specifications for the current architecture, and by
3667 GCC's implementation.
3669 For PowerPC, the following registers have specific use:
3671 R2: reserved for system use
3672 R3-R4: parameter passing and return values
3673 R5-R10: parameter passing
3674 R13: small data area pointer
3678 (U-Boot also uses R14 as internal GOT pointer.)
3680 ==> U-Boot will use R2 to hold a pointer to the global data
3682 Note: on PPC, we could use a static initializer (since the
3683 address of the global data structure is known at compile time),
3684 but it turned out that reserving a register results in somewhat
3685 smaller code - although the code savings are not that big (on
3686 average for all boards 752 bytes for the whole U-Boot image,
3687 624 text + 127 data).
3689 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3690 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3692 ==> U-Boot will use P5 to hold a pointer to the global data
3694 On ARM, the following registers are used:
3696 R0: function argument word/integer result
3697 R1-R3: function argument word
3699 R10: stack limit (used only if stack checking if enabled)
3700 R11: argument (frame) pointer
3701 R12: temporary workspace
3704 R15: program counter
3706 ==> U-Boot will use R8 to hold a pointer to the global data
3708 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3709 or current versions of GCC may "optimize" the code too much.
3714 U-Boot runs in system state and uses physical addresses, i.e. the
3715 MMU is not used either for address mapping nor for memory protection.
3717 The available memory is mapped to fixed addresses using the memory
3718 controller. In this process, a contiguous block is formed for each
3719 memory type (Flash, SDRAM, SRAM), even when it consists of several
3720 physical memory banks.
3722 U-Boot is installed in the first 128 kB of the first Flash bank (on
3723 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3724 booting and sizing and initializing DRAM, the code relocates itself
3725 to the upper end of DRAM. Immediately below the U-Boot code some
3726 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3727 configuration setting]. Below that, a structure with global Board
3728 Info data is placed, followed by the stack (growing downward).
3730 Additionally, some exception handler code is copied to the low 8 kB
3731 of DRAM (0x00000000 ... 0x00001FFF).
3733 So a typical memory configuration with 16 MB of DRAM could look like
3736 0x0000 0000 Exception Vector code
3739 0x0000 2000 Free for Application Use
3745 0x00FB FF20 Monitor Stack (Growing downward)
3746 0x00FB FFAC Board Info Data and permanent copy of global data
3747 0x00FC 0000 Malloc Arena
3750 0x00FE 0000 RAM Copy of Monitor Code
3751 ... eventually: LCD or video framebuffer
3752 ... eventually: pRAM (Protected RAM - unchanged by reset)
3753 0x00FF FFFF [End of RAM]
3756 System Initialization:
3757 ----------------------
3759 In the reset configuration, U-Boot starts at the reset entry point
3760 (on most PowerPC systens at address 0x00000100). Because of the reset
3761 configuration for CS0# this is a mirror of the onboard Flash memory.
3762 To be able to re-map memory U-Boot then jumps to its link address.
3763 To be able to implement the initialization code in C, a (small!)
3764 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3765 which provide such a feature like MPC8xx or MPC8260), or in a locked
3766 part of the data cache. After that, U-Boot initializes the CPU core,
3767 the caches and the SIU.
3769 Next, all (potentially) available memory banks are mapped using a
3770 preliminary mapping. For example, we put them on 512 MB boundaries
3771 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3772 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3773 programmed for SDRAM access. Using the temporary configuration, a
3774 simple memory test is run that determines the size of the SDRAM
3777 When there is more than one SDRAM bank, and the banks are of
3778 different size, the largest is mapped first. For equal size, the first
3779 bank (CS2#) is mapped first. The first mapping is always for address
3780 0x00000000, with any additional banks following immediately to create
3781 contiguous memory starting from 0.
3783 Then, the monitor installs itself at the upper end of the SDRAM area
3784 and allocates memory for use by malloc() and for the global Board
3785 Info data; also, the exception vector code is copied to the low RAM
3786 pages, and the final stack is set up.
3788 Only after this relocation will you have a "normal" C environment;
3789 until that you are restricted in several ways, mostly because you are
3790 running from ROM, and because the code will have to be relocated to a
3794 U-Boot Porting Guide:
3795 ----------------------
3797 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3801 int main (int argc, char *argv[])
3803 sighandler_t no_more_time;
3805 signal (SIGALRM, no_more_time);
3806 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3808 if (available_money > available_manpower) {
3809 pay consultant to port U-Boot;
3813 Download latest U-Boot source;
3815 Subscribe to u-boot-users mailing list;
3818 email ("Hi, I am new to U-Boot, how do I get started?");
3822 Read the README file in the top level directory;
3823 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3824 Read the source, Luke;
3827 if (available_money > toLocalCurrency ($2500)) {
3830 Add a lot of aggravation and time;
3833 Create your own board support subdirectory;
3835 Create your own board config file;
3839 Add / modify source code;
3843 email ("Hi, I am having problems...");
3845 Send patch file to Wolfgang;
3850 void no_more_time (int sig)
3859 All contributions to U-Boot should conform to the Linux kernel
3860 coding style; see the file "Documentation/CodingStyle" and the script
3861 "scripts/Lindent" in your Linux kernel source directory. In sources
3862 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3863 spaces before parameters to function calls) is actually used.
3865 Source files originating from a different project (for example the
3866 MTD subsystem) are generally exempt from these guidelines and are not
3867 reformated to ease subsequent migration to newer versions of those
3870 Please note that U-Boot is implemented in C (and to some small parts in
3871 Assembler); no C++ is used, so please do not use C++ style comments (//)
3874 Please also stick to the following formatting rules:
3875 - remove any trailing white space
3876 - use TAB characters for indentation, not spaces
3877 - make sure NOT to use DOS '\r\n' line feeds
3878 - do not add more than 2 empty lines to source files
3879 - do not add trailing empty lines to source files
3881 Submissions which do not conform to the standards may be returned
3882 with a request to reformat the changes.
3888 Since the number of patches for U-Boot is growing, we need to
3889 establish some rules. Submissions which do not conform to these rules
3890 may be rejected, even when they contain important and valuable stuff.
3892 Patches shall be sent to the u-boot-users mailing list.
3894 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3896 When you send a patch, please include the following information with
3899 * For bug fixes: a description of the bug and how your patch fixes
3900 this bug. Please try to include a way of demonstrating that the
3901 patch actually fixes something.
3903 * For new features: a description of the feature and your
3906 * A CHANGELOG entry as plaintext (separate from the patch)
3908 * For major contributions, your entry to the CREDITS file
3910 * When you add support for a new board, don't forget to add this
3911 board to the MAKEALL script, too.
3913 * If your patch adds new configuration options, don't forget to
3914 document these in the README file.
3916 * The patch itself. If you are using git (which is *strongly*
3917 recommended) you can easily generate the patch using the
3918 "git-format-patch". If you then use "git-send-email" to send it to
3919 the U-Boot mailing list, you will avoid most of the common problems
3920 with some other mail clients.
3922 If you cannot use git, use "diff -purN OLD NEW". If your version of
3923 diff does not support these options, then get the latest version of
3926 The current directory when running this command shall be the parent
3927 directory of the U-Boot source tree (i. e. please make sure that
3928 your patch includes sufficient directory information for the
3931 We prefer patches as plain text. MIME attachments are discouraged,
3932 and compressed attachments must not be used.
3934 * If one logical set of modifications affects or creates several
3935 files, all these changes shall be submitted in a SINGLE patch file.
3937 * Changesets that contain different, unrelated modifications shall be
3938 submitted as SEPARATE patches, one patch per changeset.
3943 * Before sending the patch, run the MAKEALL script on your patched
3944 source tree and make sure that no errors or warnings are reported
3945 for any of the boards.
3947 * Keep your modifications to the necessary minimum: A patch
3948 containing several unrelated changes or arbitrary reformats will be
3949 returned with a request to re-formatting / split it.
3951 * If you modify existing code, make sure that your new code does not
3952 add to the memory footprint of the code ;-) Small is beautiful!
3953 When adding new features, these should compile conditionally only
3954 (using #ifdef), and the resulting code with the new feature
3955 disabled must not need more memory than the old code without your
3958 * Remember that there is a size limit of 40 kB per message on the
3959 u-boot-users mailing list. Bigger patches will be moderated. If
3960 they are reasonable and not bigger than 100 kB, they will be
3961 acknowledged. Even bigger patches should be avoided.
projects / u-boot / blob