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_CDP * Cisco Discover Protocol support
627 CONFIG_CMD_FSL * Microblaze FSL support
630 EXAMPLE: If you want all functions except of network
631 support you can write:
633 #include "config_cmd_all.h"
634 #undef CONFIG_CMD_NET
637 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
639 Note: Don't enable the "icache" and "dcache" commands
640 (configuration option CONFIG_CMD_CACHE) unless you know
641 what you (and your U-Boot users) are doing. Data
642 cache cannot be enabled on systems like the 8xx or
643 8260 (where accesses to the IMMR region must be
644 uncached), and it cannot be disabled on all other
645 systems where we (mis-) use the data cache to hold an
646 initial stack and some data.
649 XXX - this list needs to get updated!
653 If this variable is defined, it enables watchdog
654 support. There must be support in the platform specific
655 code for a watchdog. For the 8xx and 8260 CPUs, the
656 SIU Watchdog feature is enabled in the SYPCR
660 CONFIG_VERSION_VARIABLE
661 If this variable is defined, an environment variable
662 named "ver" is created by U-Boot showing the U-Boot
663 version as printed by the "version" command.
664 This variable is readonly.
668 When CONFIG_CMD_DATE is selected, the type of the RTC
669 has to be selected, too. Define exactly one of the
672 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
673 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
674 CONFIG_RTC_MC13783 - use MC13783 RTC
675 CONFIG_RTC_MC146818 - use MC146818 RTC
676 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
677 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
678 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
679 CONFIG_RTC_DS164x - use Dallas DS164x RTC
680 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
681 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
682 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
684 Note that if the RTC uses I2C, then the I2C interface
685 must also be configured. See I2C Support, below.
689 When CONFIG_TIMESTAMP is selected, the timestamp
690 (date and time) of an image is printed by image
691 commands like bootm or iminfo. This option is
692 automatically enabled when you select CONFIG_CMD_DATE .
695 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
696 and/or CONFIG_ISO_PARTITION
698 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
699 CONFIG_CMD_SCSI) you must configure support for at
700 least one partition type as well.
703 CONFIG_IDE_RESET_ROUTINE - this is defined in several
704 board configurations files but used nowhere!
706 CONFIG_IDE_RESET - is this is defined, IDE Reset will
707 be performed by calling the function
708 ide_set_reset(int reset)
709 which has to be defined in a board specific file
714 Set this to enable ATAPI support.
719 Set this to enable support for disks larger than 137GB
720 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
721 Whithout these , LBA48 support uses 32bit variables and will 'only'
722 support disks up to 2.1TB.
725 When enabled, makes the IDE subsystem use 64bit sector addresses.
729 At the moment only there is only support for the
730 SYM53C8XX SCSI controller; define
731 CONFIG_SCSI_SYM53C8XX to enable it.
733 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
734 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
735 CFG_SCSI_MAX_LUN] can be adjusted to define the
736 maximum numbers of LUNs, SCSI ID's and target
738 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
740 - NETWORK Support (PCI):
742 Support for Intel 8254x gigabit chips.
744 CONFIG_E1000_FALLBACK_MAC
745 default MAC for empty eeprom after production.
748 Support for Intel 82557/82559/82559ER chips.
749 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
750 write routine for first time initialisation.
753 Support for Digital 2114x chips.
754 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
755 modem chip initialisation (KS8761/QS6611).
758 Support for National dp83815 chips.
761 Support for National dp8382[01] gigabit chips.
763 - NETWORK Support (other):
765 CONFIG_DRIVER_LAN91C96
766 Support for SMSC's LAN91C96 chips.
769 Define this to hold the physical address
770 of the LAN91C96's I/O space
772 CONFIG_LAN91C96_USE_32_BIT
773 Define this to enable 32 bit addressing
775 CONFIG_DRIVER_SMC91111
776 Support for SMSC's LAN91C111 chip
779 Define this to hold the physical address
780 of the device (I/O space)
782 CONFIG_SMC_USE_32_BIT
783 Define this if data bus is 32 bits
785 CONFIG_SMC_USE_IOFUNCS
786 Define this to use i/o functions instead of macros
787 (some hardware wont work with macros)
790 At the moment only the UHCI host controller is
791 supported (PIP405, MIP405, MPC5200); define
792 CONFIG_USB_UHCI to enable it.
793 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
794 and define CONFIG_USB_STORAGE to enable the USB
797 Supported are USB Keyboards and USB Floppy drives
799 MPC5200 USB requires additional defines:
801 for 528 MHz Clock: 0x0001bbbb
803 for differential drivers: 0x00001000
804 for single ended drivers: 0x00005000
806 May be defined to allow interrupt polling
807 instead of using asynchronous interrupts
810 Define the below if you wish to use the USB console.
811 Once firmware is rebuilt from a serial console issue the
812 command "setenv stdin usbtty; setenv stdout usbtty" and
813 attach your usb cable. The Unix command "dmesg" should print
814 it has found a new device. The environment variable usbtty
815 can be set to gserial or cdc_acm to enable your device to
816 appear to a USB host as a Linux gserial device or a
817 Common Device Class Abstract Control Model serial device.
818 If you select usbtty = gserial you should be able to enumerate
820 # modprobe usbserial vendor=0xVendorID product=0xProductID
821 else if using cdc_acm, simply setting the environment
822 variable usbtty to be cdc_acm should suffice. The following
823 might be defined in YourBoardName.h
826 Define this to build a UDC device
829 Define this to have a tty type of device available to
830 talk to the UDC device
832 CFG_CONSOLE_IS_IN_ENV
833 Define this if you want stdin, stdout &/or stderr to
837 CFG_USB_EXTC_CLK 0xBLAH
838 Derive USB clock from external clock "blah"
839 - CFG_USB_EXTC_CLK 0x02
841 CFG_USB_BRG_CLK 0xBLAH
842 Derive USB clock from brgclk
843 - CFG_USB_BRG_CLK 0x04
845 If you have a USB-IF assigned VendorID then you may wish to
846 define your own vendor specific values either in BoardName.h
847 or directly in usbd_vendor_info.h. If you don't define
848 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
849 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
850 should pretend to be a Linux device to it's target host.
852 CONFIG_USBD_MANUFACTURER
853 Define this string as the name of your company for
854 - CONFIG_USBD_MANUFACTURER "my company"
856 CONFIG_USBD_PRODUCT_NAME
857 Define this string as the name of your product
858 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
861 Define this as your assigned Vendor ID from the USB
862 Implementors Forum. This *must* be a genuine Vendor ID
863 to avoid polluting the USB namespace.
864 - CONFIG_USBD_VENDORID 0xFFFF
866 CONFIG_USBD_PRODUCTID
867 Define this as the unique Product ID
869 - CONFIG_USBD_PRODUCTID 0xFFFF
873 The MMC controller on the Intel PXA is supported. To
874 enable this define CONFIG_MMC. The MMC can be
875 accessed from the boot prompt by mapping the device
876 to physical memory similar to flash. Command line is
877 enabled with CONFIG_CMD_MMC. The MMC driver also works with
878 the FAT fs. This is enabled with CONFIG_CMD_FAT.
880 - Journaling Flash filesystem support:
881 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
882 CONFIG_JFFS2_NAND_DEV
883 Define these for a default partition on a NAND device
885 CFG_JFFS2_FIRST_SECTOR,
886 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
887 Define these for a default partition on a NOR device
890 Define this to create an own partition. You have to provide a
891 function struct part_info* jffs2_part_info(int part_num)
893 If you define only one JFFS2 partition you may also want to
894 #define CFG_JFFS_SINGLE_PART 1
895 to disable the command chpart. This is the default when you
896 have not defined a custom partition
901 Define this to enable standard (PC-Style) keyboard
905 Standard PC keyboard driver with US (is default) and
906 GERMAN key layout (switch via environment 'keymap=de') support.
907 Export function i8042_kbd_init, i8042_tstc and i8042_getc
908 for cfb_console. Supports cursor blinking.
913 Define this to enable video support (for output to
918 Enable Chips & Technologies 69000 Video chip
920 CONFIG_VIDEO_SMI_LYNXEM
921 Enable Silicon Motion SMI 712/710/810 Video chip. The
922 video output is selected via environment 'videoout'
923 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
926 For the CT69000 and SMI_LYNXEM drivers, videomode is
927 selected via environment 'videomode'. Two diferent ways
929 - "videomode=num" 'num' is a standard LiLo mode numbers.
930 Following standard modes are supported (* is default):
932 Colors 640x480 800x600 1024x768 1152x864 1280x1024
933 -------------+---------------------------------------------
934 8 bits | 0x301* 0x303 0x305 0x161 0x307
935 15 bits | 0x310 0x313 0x316 0x162 0x319
936 16 bits | 0x311 0x314 0x317 0x163 0x31A
937 24 bits | 0x312 0x315 0x318 ? 0x31B
938 -------------+---------------------------------------------
939 (i.e. setenv videomode 317; saveenv; reset;)
941 - "videomode=bootargs" all the video parameters are parsed
942 from the bootargs. (See drivers/video/videomodes.c)
945 CONFIG_VIDEO_SED13806
946 Enable Epson SED13806 driver. This driver supports 8bpp
947 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
948 or CONFIG_VIDEO_SED13806_16BPP
953 Define this to enable a custom keyboard support.
954 This simply calls drv_keyboard_init() which must be
955 defined in your board-specific files.
956 The only board using this so far is RBC823.
958 - LCD Support: CONFIG_LCD
960 Define this to enable LCD support (for output to LCD
961 display); also select one of the supported displays
962 by defining one of these:
966 HITACHI TX09D70VM1CCA, 3.5", 240x320.
968 CONFIG_NEC_NL6448AC33:
970 NEC NL6448AC33-18. Active, color, single scan.
972 CONFIG_NEC_NL6448BC20
974 NEC NL6448BC20-08. 6.5", 640x480.
975 Active, color, single scan.
977 CONFIG_NEC_NL6448BC33_54
979 NEC NL6448BC33-54. 10.4", 640x480.
980 Active, color, single scan.
984 Sharp 320x240. Active, color, single scan.
985 It isn't 16x9, and I am not sure what it is.
987 CONFIG_SHARP_LQ64D341
989 Sharp LQ64D341 display, 640x480.
990 Active, color, single scan.
994 HLD1045 display, 640x480.
995 Active, color, single scan.
999 Optrex CBL50840-2 NF-FW 99 22 M5
1001 Hitachi LMG6912RPFC-00T
1005 320x240. Black & white.
1007 Normally display is black on white background; define
1008 CFG_WHITE_ON_BLACK to get it inverted.
1010 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1012 If this option is set, the environment is checked for
1013 a variable "splashimage". If found, the usual display
1014 of logo, copyright and system information on the LCD
1015 is suppressed and the BMP image at the address
1016 specified in "splashimage" is loaded instead. The
1017 console is redirected to the "nulldev", too. This
1018 allows for a "silent" boot where a splash screen is
1019 loaded very quickly after power-on.
1021 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1023 If this option is set, additionally to standard BMP
1024 images, gzipped BMP images can be displayed via the
1025 splashscreen support or the bmp command.
1027 - Compression support:
1030 If this option is set, support for bzip2 compressed
1031 images is included. If not, only uncompressed and gzip
1032 compressed images are supported.
1034 NOTE: the bzip2 algorithm requires a lot of RAM, so
1035 the malloc area (as defined by CFG_MALLOC_LEN) should
1041 The address of PHY on MII bus.
1043 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1045 The clock frequency of the MII bus
1049 If this option is set, support for speed/duplex
1050 detection of Gigabit PHY is included.
1052 CONFIG_PHY_RESET_DELAY
1054 Some PHY like Intel LXT971A need extra delay after
1055 reset before any MII register access is possible.
1056 For such PHY, set this option to the usec delay
1057 required. (minimum 300usec for LXT971A)
1059 CONFIG_PHY_CMD_DELAY (ppc4xx)
1061 Some PHY like Intel LXT971A need extra delay after
1062 command issued before MII status register can be read
1069 Define a default value for ethernet address to use
1070 for the respective ethernet interface, in case this
1071 is not determined automatically.
1076 Define a default value for the IP address to use for
1077 the default ethernet interface, in case this is not
1078 determined through e.g. bootp.
1080 - Server IP address:
1083 Defines a default value for theIP address of a TFTP
1084 server to contact when using the "tftboot" command.
1086 - Multicast TFTP Mode:
1089 Defines whether you want to support multicast TFTP as per
1090 rfc-2090; for example to work with atftp. Lets lots of targets
1091 tftp down the same boot image concurrently. Note: the ethernet
1092 driver in use must provide a function: mcast() to join/leave a
1095 CONFIG_BOOTP_RANDOM_DELAY
1096 - BOOTP Recovery Mode:
1097 CONFIG_BOOTP_RANDOM_DELAY
1099 If you have many targets in a network that try to
1100 boot using BOOTP, you may want to avoid that all
1101 systems send out BOOTP requests at precisely the same
1102 moment (which would happen for instance at recovery
1103 from a power failure, when all systems will try to
1104 boot, thus flooding the BOOTP server. Defining
1105 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1106 inserted before sending out BOOTP requests. The
1107 following delays are inserted then:
1109 1st BOOTP request: delay 0 ... 1 sec
1110 2nd BOOTP request: delay 0 ... 2 sec
1111 3rd BOOTP request: delay 0 ... 4 sec
1113 BOOTP requests: delay 0 ... 8 sec
1115 - DHCP Advanced Options:
1116 You can fine tune the DHCP functionality by defining
1117 CONFIG_BOOTP_* symbols:
1119 CONFIG_BOOTP_SUBNETMASK
1120 CONFIG_BOOTP_GATEWAY
1121 CONFIG_BOOTP_HOSTNAME
1122 CONFIG_BOOTP_NISDOMAIN
1123 CONFIG_BOOTP_BOOTPATH
1124 CONFIG_BOOTP_BOOTFILESIZE
1127 CONFIG_BOOTP_SEND_HOSTNAME
1128 CONFIG_BOOTP_NTPSERVER
1129 CONFIG_BOOTP_TIMEOFFSET
1130 CONFIG_BOOTP_VENDOREX
1132 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1133 environment variable, not the BOOTP server.
1135 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1136 serverip from a DHCP server, it is possible that more
1137 than one DNS serverip is offered to the client.
1138 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1139 serverip will be stored in the additional environment
1140 variable "dnsip2". The first DNS serverip is always
1141 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1144 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1145 to do a dynamic update of a DNS server. To do this, they
1146 need the hostname of the DHCP requester.
1147 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1148 of the "hostname" environment variable is passed as
1149 option 12 to the DHCP server.
1151 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1153 A 32bit value in microseconds for a delay between
1154 receiving a "DHCP Offer" and sending the "DHCP Request".
1155 This fixes a problem with certain DHCP servers that don't
1156 respond 100% of the time to a "DHCP request". E.g. On an
1157 AT91RM9200 processor running at 180MHz, this delay needed
1158 to be *at least* 15,000 usec before a Windows Server 2003
1159 DHCP server would reply 100% of the time. I recommend at
1160 least 50,000 usec to be safe. The alternative is to hope
1161 that one of the retries will be successful but note that
1162 the DHCP timeout and retry process takes a longer than
1166 CONFIG_CDP_DEVICE_ID
1168 The device id used in CDP trigger frames.
1170 CONFIG_CDP_DEVICE_ID_PREFIX
1172 A two character string which is prefixed to the MAC address
1177 A printf format string which contains the ascii name of
1178 the port. Normally is set to "eth%d" which sets
1179 eth0 for the first ethernet, eth1 for the second etc.
1181 CONFIG_CDP_CAPABILITIES
1183 A 32bit integer which indicates the device capabilities;
1184 0x00000010 for a normal host which does not forwards.
1188 An ascii string containing the version of the software.
1192 An ascii string containing the name of the platform.
1196 A 32bit integer sent on the trigger.
1198 CONFIG_CDP_POWER_CONSUMPTION
1200 A 16bit integer containing the power consumption of the
1201 device in .1 of milliwatts.
1203 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1205 A byte containing the id of the VLAN.
1207 - Status LED: CONFIG_STATUS_LED
1209 Several configurations allow to display the current
1210 status using a LED. For instance, the LED will blink
1211 fast while running U-Boot code, stop blinking as
1212 soon as a reply to a BOOTP request was received, and
1213 start blinking slow once the Linux kernel is running
1214 (supported by a status LED driver in the Linux
1215 kernel). Defining CONFIG_STATUS_LED enables this
1218 - CAN Support: CONFIG_CAN_DRIVER
1220 Defining CONFIG_CAN_DRIVER enables CAN driver support
1221 on those systems that support this (optional)
1222 feature, like the TQM8xxL modules.
1224 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1226 These enable I2C serial bus commands. Defining either of
1227 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1228 include the appropriate I2C driver for the selected cpu.
1230 This will allow you to use i2c commands at the u-boot
1231 command line (as long as you set CONFIG_CMD_I2C in
1232 CONFIG_COMMANDS) and communicate with i2c based realtime
1233 clock chips. See common/cmd_i2c.c for a description of the
1234 command line interface.
1236 CONFIG_I2C_CMD_TREE is a recommended option that places
1237 all I2C commands under a single 'i2c' root command. The
1238 older 'imm', 'imd', 'iprobe' etc. commands are considered
1239 deprecated and may disappear in the future.
1241 CONFIG_HARD_I2C selects a hardware I2C controller.
1243 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1244 bit-banging) driver instead of CPM or similar hardware
1247 There are several other quantities that must also be
1248 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1250 In both cases you will need to define CFG_I2C_SPEED
1251 to be the frequency (in Hz) at which you wish your i2c bus
1252 to run and CFG_I2C_SLAVE to be the address of this node (ie
1253 the cpu's i2c node address).
1255 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1256 sets the cpu up as a master node and so its address should
1257 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1258 p.16-473). So, set CFG_I2C_SLAVE to 0.
1260 That's all that's required for CONFIG_HARD_I2C.
1262 If you use the software i2c interface (CONFIG_SOFT_I2C)
1263 then the following macros need to be defined (examples are
1264 from include/configs/lwmon.h):
1268 (Optional). Any commands necessary to enable the I2C
1269 controller or configure ports.
1271 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1275 (Only for MPC8260 CPU). The I/O port to use (the code
1276 assumes both bits are on the same port). Valid values
1277 are 0..3 for ports A..D.
1281 The code necessary to make the I2C data line active
1282 (driven). If the data line is open collector, this
1285 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1289 The code necessary to make the I2C data line tri-stated
1290 (inactive). If the data line is open collector, this
1293 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1297 Code that returns TRUE if the I2C data line is high,
1300 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1304 If <bit> is TRUE, sets the I2C data line high. If it
1305 is FALSE, it clears it (low).
1307 eg: #define I2C_SDA(bit) \
1308 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1309 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1313 If <bit> is TRUE, sets the I2C clock line high. If it
1314 is FALSE, it clears it (low).
1316 eg: #define I2C_SCL(bit) \
1317 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1318 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1322 This delay is invoked four times per clock cycle so this
1323 controls the rate of data transfer. The data rate thus
1324 is 1 / (I2C_DELAY * 4). Often defined to be something
1327 #define I2C_DELAY udelay(2)
1331 When a board is reset during an i2c bus transfer
1332 chips might think that the current transfer is still
1333 in progress. On some boards it is possible to access
1334 the i2c SCLK line directly, either by using the
1335 processor pin as a GPIO or by having a second pin
1336 connected to the bus. If this option is defined a
1337 custom i2c_init_board() routine in boards/xxx/board.c
1338 is run early in the boot sequence.
1340 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1342 This option enables configuration of bi_iic_fast[] flags
1343 in u-boot bd_info structure based on u-boot environment
1344 variable "i2cfast". (see also i2cfast)
1346 CONFIG_I2C_MULTI_BUS
1348 This option allows the use of multiple I2C buses, each of which
1349 must have a controller. At any point in time, only one bus is
1350 active. To switch to a different bus, use the 'i2c dev' command.
1351 Note that bus numbering is zero-based.
1355 This option specifies a list of I2C devices that will be skipped
1356 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1357 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1358 pairs. Otherwise, specify a 1D array of device addresses
1361 #undef CONFIG_I2C_MULTI_BUS
1362 #define CFG_I2C_NOPROBES {0x50,0x68}
1364 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1366 #define CONFIG_I2C_MULTI_BUS
1367 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1369 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1373 If defined, then this indicates the I2C bus number for DDR SPD.
1374 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1378 If defined, then this indicates the I2C bus number for the RTC.
1379 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1383 If defined, then this indicates the I2C bus number for the DTT.
1384 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1388 Define this option if you want to use Freescale's I2C driver in
1389 drivers/i2c/fsl_i2c.c.
1392 - SPI Support: CONFIG_SPI
1394 Enables SPI driver (so far only tested with
1395 SPI EEPROM, also an instance works with Crystal A/D and
1396 D/As on the SACSng board)
1400 Enables extended (16-bit) SPI EEPROM addressing.
1401 (symmetrical to CONFIG_I2C_X)
1405 Enables a software (bit-bang) SPI driver rather than
1406 using hardware support. This is a general purpose
1407 driver that only requires three general I/O port pins
1408 (two outputs, one input) to function. If this is
1409 defined, the board configuration must define several
1410 SPI configuration items (port pins to use, etc). For
1411 an example, see include/configs/sacsng.h.
1415 Enables a hardware SPI driver for general-purpose reads
1416 and writes. As with CONFIG_SOFT_SPI, the board configuration
1417 must define a list of chip-select function pointers.
1418 Currently supported on some MPC8xxx processors. For an
1419 example, see include/configs/mpc8349emds.h.
1423 Enables the driver for the SPI controllers on i.MX and MXC
1424 SoCs. Currently only i.MX31 is supported.
1426 - FPGA Support: CONFIG_FPGA
1428 Enables FPGA subsystem.
1430 CONFIG_FPGA_<vendor>
1432 Enables support for specific chip vendors.
1435 CONFIG_FPGA_<family>
1437 Enables support for FPGA family.
1438 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1442 Specify the number of FPGA devices to support.
1444 CFG_FPGA_PROG_FEEDBACK
1446 Enable printing of hash marks during FPGA configuration.
1450 Enable checks on FPGA configuration interface busy
1451 status by the configuration function. This option
1452 will require a board or device specific function to
1457 If defined, a function that provides delays in the FPGA
1458 configuration driver.
1460 CFG_FPGA_CHECK_CTRLC
1461 Allow Control-C to interrupt FPGA configuration
1463 CFG_FPGA_CHECK_ERROR
1465 Check for configuration errors during FPGA bitfile
1466 loading. For example, abort during Virtex II
1467 configuration if the INIT_B line goes low (which
1468 indicated a CRC error).
1472 Maximum time to wait for the INIT_B line to deassert
1473 after PROB_B has been deasserted during a Virtex II
1474 FPGA configuration sequence. The default time is 500
1479 Maximum time to wait for BUSY to deassert during
1480 Virtex II FPGA configuration. The default is 5 mS.
1482 CFG_FPGA_WAIT_CONFIG
1484 Time to wait after FPGA configuration. The default is
1487 - Configuration Management:
1490 If defined, this string will be added to the U-Boot
1491 version information (U_BOOT_VERSION)
1493 - Vendor Parameter Protection:
1495 U-Boot considers the values of the environment
1496 variables "serial#" (Board Serial Number) and
1497 "ethaddr" (Ethernet Address) to be parameters that
1498 are set once by the board vendor / manufacturer, and
1499 protects these variables from casual modification by
1500 the user. Once set, these variables are read-only,
1501 and write or delete attempts are rejected. You can
1502 change this behviour:
1504 If CONFIG_ENV_OVERWRITE is #defined in your config
1505 file, the write protection for vendor parameters is
1506 completely disabled. Anybody can change or delete
1509 Alternatively, if you #define _both_ CONFIG_ETHADDR
1510 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1511 ethernet address is installed in the environment,
1512 which can be changed exactly ONCE by the user. [The
1513 serial# is unaffected by this, i. e. it remains
1519 Define this variable to enable the reservation of
1520 "protected RAM", i. e. RAM which is not overwritten
1521 by U-Boot. Define CONFIG_PRAM to hold the number of
1522 kB you want to reserve for pRAM. You can overwrite
1523 this default value by defining an environment
1524 variable "pram" to the number of kB you want to
1525 reserve. Note that the board info structure will
1526 still show the full amount of RAM. If pRAM is
1527 reserved, a new environment variable "mem" will
1528 automatically be defined to hold the amount of
1529 remaining RAM in a form that can be passed as boot
1530 argument to Linux, for instance like that:
1532 setenv bootargs ... mem=\${mem}
1535 This way you can tell Linux not to use this memory,
1536 either, which results in a memory region that will
1537 not be affected by reboots.
1539 *WARNING* If your board configuration uses automatic
1540 detection of the RAM size, you must make sure that
1541 this memory test is non-destructive. So far, the
1542 following board configurations are known to be
1545 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1546 HERMES, IP860, RPXlite, LWMON, LANTEC,
1547 PCU_E, FLAGADM, TQM8260
1552 Define this variable to stop the system in case of a
1553 fatal error, so that you have to reset it manually.
1554 This is probably NOT a good idea for an embedded
1555 system where you want to system to reboot
1556 automatically as fast as possible, but it may be
1557 useful during development since you can try to debug
1558 the conditions that lead to the situation.
1560 CONFIG_NET_RETRY_COUNT
1562 This variable defines the number of retries for
1563 network operations like ARP, RARP, TFTP, or BOOTP
1564 before giving up the operation. If not defined, a
1565 default value of 5 is used.
1569 Timeout waiting for an ARP reply in milliseconds.
1571 - Command Interpreter:
1572 CONFIG_AUTO_COMPLETE
1574 Enable auto completion of commands using TAB.
1576 Note that this feature has NOT been implemented yet
1577 for the "hush" shell.
1582 Define this variable to enable the "hush" shell (from
1583 Busybox) as command line interpreter, thus enabling
1584 powerful command line syntax like
1585 if...then...else...fi conditionals or `&&' and '||'
1586 constructs ("shell scripts").
1588 If undefined, you get the old, much simpler behaviour
1589 with a somewhat smaller memory footprint.
1594 This defines the secondary prompt string, which is
1595 printed when the command interpreter needs more input
1596 to complete a command. Usually "> ".
1600 In the current implementation, the local variables
1601 space and global environment variables space are
1602 separated. Local variables are those you define by
1603 simply typing `name=value'. To access a local
1604 variable later on, you have write `$name' or
1605 `${name}'; to execute the contents of a variable
1606 directly type `$name' at the command prompt.
1608 Global environment variables are those you use
1609 setenv/printenv to work with. To run a command stored
1610 in such a variable, you need to use the run command,
1611 and you must not use the '$' sign to access them.
1613 To store commands and special characters in a
1614 variable, please use double quotation marks
1615 surrounding the whole text of the variable, instead
1616 of the backslashes before semicolons and special
1619 - Commandline Editing and History:
1620 CONFIG_CMDLINE_EDITING
1622 Enable editiong and History functions for interactive
1623 commandline input operations
1625 - Default Environment:
1626 CONFIG_EXTRA_ENV_SETTINGS
1628 Define this to contain any number of null terminated
1629 strings (variable = value pairs) that will be part of
1630 the default environment compiled into the boot image.
1632 For example, place something like this in your
1633 board's config file:
1635 #define CONFIG_EXTRA_ENV_SETTINGS \
1639 Warning: This method is based on knowledge about the
1640 internal format how the environment is stored by the
1641 U-Boot code. This is NOT an official, exported
1642 interface! Although it is unlikely that this format
1643 will change soon, there is no guarantee either.
1644 You better know what you are doing here.
1646 Note: overly (ab)use of the default environment is
1647 discouraged. Make sure to check other ways to preset
1648 the environment like the autoscript function or the
1651 - DataFlash Support:
1652 CONFIG_HAS_DATAFLASH
1654 Defining this option enables DataFlash features and
1655 allows to read/write in Dataflash via the standard
1658 - SystemACE Support:
1661 Adding this option adds support for Xilinx SystemACE
1662 chips attached via some sort of local bus. The address
1663 of the chip must alsh be defined in the
1664 CFG_SYSTEMACE_BASE macro. For example:
1666 #define CONFIG_SYSTEMACE
1667 #define CFG_SYSTEMACE_BASE 0xf0000000
1669 When SystemACE support is added, the "ace" device type
1670 becomes available to the fat commands, i.e. fatls.
1672 - TFTP Fixed UDP Port:
1675 If this is defined, the environment variable tftpsrcp
1676 is used to supply the TFTP UDP source port value.
1677 If tftpsrcp isn't defined, the normal pseudo-random port
1678 number generator is used.
1680 Also, the environment variable tftpdstp is used to supply
1681 the TFTP UDP destination port value. If tftpdstp isn't
1682 defined, the normal port 69 is used.
1684 The purpose for tftpsrcp is to allow a TFTP server to
1685 blindly start the TFTP transfer using the pre-configured
1686 target IP address and UDP port. This has the effect of
1687 "punching through" the (Windows XP) firewall, allowing
1688 the remainder of the TFTP transfer to proceed normally.
1689 A better solution is to properly configure the firewall,
1690 but sometimes that is not allowed.
1692 - Show boot progress:
1693 CONFIG_SHOW_BOOT_PROGRESS
1695 Defining this option allows to add some board-
1696 specific code (calling a user-provided function
1697 "show_boot_progress(int)") that enables you to show
1698 the system's boot progress on some display (for
1699 example, some LED's) on your board. At the moment,
1700 the following checkpoints are implemented:
1702 Legacy uImage format:
1705 1 common/cmd_bootm.c before attempting to boot an image
1706 -1 common/cmd_bootm.c Image header has bad magic number
1707 2 common/cmd_bootm.c Image header has correct magic number
1708 -2 common/cmd_bootm.c Image header has bad checksum
1709 3 common/cmd_bootm.c Image header has correct checksum
1710 -3 common/cmd_bootm.c Image data has bad checksum
1711 4 common/cmd_bootm.c Image data has correct checksum
1712 -4 common/cmd_bootm.c Image is for unsupported architecture
1713 5 common/cmd_bootm.c Architecture check OK
1714 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1715 6 common/cmd_bootm.c Image Type check OK
1716 -6 common/cmd_bootm.c gunzip uncompression error
1717 -7 common/cmd_bootm.c Unimplemented compression type
1718 7 common/cmd_bootm.c Uncompression OK
1719 8 common/cmd_bootm.c No uncompress/copy overwrite error
1720 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1722 9 common/image.c Start initial ramdisk verification
1723 -10 common/image.c Ramdisk header has bad magic number
1724 -11 common/image.c Ramdisk header has bad checksum
1725 10 common/image.c Ramdisk header is OK
1726 -12 common/image.c Ramdisk data has bad checksum
1727 11 common/image.c Ramdisk data has correct checksum
1728 12 common/image.c Ramdisk verification complete, start loading
1729 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1730 13 common/image.c Start multifile image verification
1731 14 common/image.c No initial ramdisk, no multifile, continue.
1733 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1735 -30 lib_ppc/board.c Fatal error, hang the system
1736 -31 post/post.c POST test failed, detected by post_output_backlog()
1737 -32 post/post.c POST test failed, detected by post_run_single()
1739 34 common/cmd_doc.c before loading a Image from a DOC device
1740 -35 common/cmd_doc.c Bad usage of "doc" command
1741 35 common/cmd_doc.c correct usage of "doc" command
1742 -36 common/cmd_doc.c No boot device
1743 36 common/cmd_doc.c correct boot device
1744 -37 common/cmd_doc.c Unknown Chip ID on boot device
1745 37 common/cmd_doc.c correct chip ID found, device available
1746 -38 common/cmd_doc.c Read Error on boot device
1747 38 common/cmd_doc.c reading Image header from DOC device OK
1748 -39 common/cmd_doc.c Image header has bad magic number
1749 39 common/cmd_doc.c Image header has correct magic number
1750 -40 common/cmd_doc.c Error reading Image from DOC device
1751 40 common/cmd_doc.c Image header has correct magic number
1752 41 common/cmd_ide.c before loading a Image from a IDE device
1753 -42 common/cmd_ide.c Bad usage of "ide" command
1754 42 common/cmd_ide.c correct usage of "ide" command
1755 -43 common/cmd_ide.c No boot device
1756 43 common/cmd_ide.c boot device found
1757 -44 common/cmd_ide.c Device not available
1758 44 common/cmd_ide.c Device available
1759 -45 common/cmd_ide.c wrong partition selected
1760 45 common/cmd_ide.c partition selected
1761 -46 common/cmd_ide.c Unknown partition table
1762 46 common/cmd_ide.c valid partition table found
1763 -47 common/cmd_ide.c Invalid partition type
1764 47 common/cmd_ide.c correct partition type
1765 -48 common/cmd_ide.c Error reading Image Header on boot device
1766 48 common/cmd_ide.c reading Image Header from IDE device OK
1767 -49 common/cmd_ide.c Image header has bad magic number
1768 49 common/cmd_ide.c Image header has correct magic number
1769 -50 common/cmd_ide.c Image header has bad checksum
1770 50 common/cmd_ide.c Image header has correct checksum
1771 -51 common/cmd_ide.c Error reading Image from IDE device
1772 51 common/cmd_ide.c reading Image from IDE device OK
1773 52 common/cmd_nand.c before loading a Image from a NAND device
1774 -53 common/cmd_nand.c Bad usage of "nand" command
1775 53 common/cmd_nand.c correct usage of "nand" command
1776 -54 common/cmd_nand.c No boot device
1777 54 common/cmd_nand.c boot device found
1778 -55 common/cmd_nand.c Unknown Chip ID on boot device
1779 55 common/cmd_nand.c correct chip ID found, device available
1780 -56 common/cmd_nand.c Error reading Image Header on boot device
1781 56 common/cmd_nand.c reading Image Header from NAND device OK
1782 -57 common/cmd_nand.c Image header has bad magic number
1783 57 common/cmd_nand.c Image header has correct magic number
1784 -58 common/cmd_nand.c Error reading Image from NAND device
1785 58 common/cmd_nand.c reading Image from NAND device OK
1787 -60 common/env_common.c Environment has a bad CRC, using default
1789 64 net/eth.c starting with Ethernetconfiguration.
1790 -64 net/eth.c no Ethernet found.
1791 65 net/eth.c Ethernet found.
1793 -80 common/cmd_net.c usage wrong
1794 80 common/cmd_net.c before calling NetLoop()
1795 -81 common/cmd_net.c some error in NetLoop() occured
1796 81 common/cmd_net.c NetLoop() back without error
1797 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1798 82 common/cmd_net.c trying automatic boot
1799 83 common/cmd_net.c running autoscript
1800 -83 common/cmd_net.c some error in automatic boot or autoscript
1801 84 common/cmd_net.c end without errors
1806 100 common/cmd_bootm.c Kernel FIT Image has correct format
1807 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1808 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1809 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1810 102 common/cmd_bootm.c Kernel unit name specified
1811 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1812 103 common/cmd_bootm.c Found configuration node
1813 104 common/cmd_bootm.c Got kernel subimage node offset
1814 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1815 105 common/cmd_bootm.c Kernel subimage hash verification OK
1816 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1817 106 common/cmd_bootm.c Architecture check OK
1818 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1819 107 common/cmd_bootm.c Kernel subimge type OK
1820 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1821 108 common/cmd_bootm.c Got kernel subimage data/size
1822 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1823 -109 common/cmd_bootm.c Can't get kernel subimage type
1824 -110 common/cmd_bootm.c Can't get kernel subimage comp
1825 -111 common/cmd_bootm.c Can't get kernel subimage os
1826 -112 common/cmd_bootm.c Can't get kernel subimage load address
1827 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1829 120 common/image.c Start initial ramdisk verification
1830 -120 common/image.c Ramdisk FIT image has incorrect format
1831 121 common/image.c Ramdisk FIT image has correct format
1832 122 common/image.c No Ramdisk subimage unit name, using configuration
1833 -122 common/image.c Can't get configuration for ramdisk subimage
1834 123 common/image.c Ramdisk unit name specified
1835 -124 common/image.c Can't get ramdisk subimage node offset
1836 125 common/image.c Got ramdisk subimage node offset
1837 -125 common/image.c Ramdisk subimage hash verification failed
1838 126 common/image.c Ramdisk subimage hash verification OK
1839 -126 common/image.c Ramdisk subimage for unsupported architecture
1840 127 common/image.c Architecture check OK
1841 -127 common/image.c Can't get ramdisk subimage data/size
1842 128 common/image.c Got ramdisk subimage data/size
1843 129 common/image.c Can't get ramdisk load address
1844 -129 common/image.c Got ramdisk load address
1846 -130 common/cmd_doc.c Icorrect FIT image format
1847 131 common/cmd_doc.c FIT image format OK
1849 -140 common/cmd_ide.c Icorrect FIT image format
1850 141 common/cmd_ide.c FIT image format OK
1852 -150 common/cmd_nand.c Icorrect FIT image format
1853 151 common/cmd_nand.c FIT image format OK
1859 [so far only for SMDK2400 and TRAB boards]
1861 - Modem support endable:
1862 CONFIG_MODEM_SUPPORT
1864 - RTS/CTS Flow control enable:
1867 - Modem debug support:
1868 CONFIG_MODEM_SUPPORT_DEBUG
1870 Enables debugging stuff (char screen[1024], dbg())
1871 for modem support. Useful only with BDI2000.
1873 - Interrupt support (PPC):
1875 There are common interrupt_init() and timer_interrupt()
1876 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1877 for cpu specific initialization. interrupt_init_cpu()
1878 should set decrementer_count to appropriate value. If
1879 cpu resets decrementer automatically after interrupt
1880 (ppc4xx) it should set decrementer_count to zero.
1881 timer_interrupt() calls timer_interrupt_cpu() for cpu
1882 specific handling. If board has watchdog / status_led
1883 / other_activity_monitor it works automatically from
1884 general timer_interrupt().
1888 In the target system modem support is enabled when a
1889 specific key (key combination) is pressed during
1890 power-on. Otherwise U-Boot will boot normally
1891 (autoboot). The key_pressed() fuction is called from
1892 board_init(). Currently key_pressed() is a dummy
1893 function, returning 1 and thus enabling modem
1896 If there are no modem init strings in the
1897 environment, U-Boot proceed to autoboot; the
1898 previous output (banner, info printfs) will be
1901 See also: doc/README.Modem
1904 Configuration Settings:
1905 -----------------------
1907 - CFG_LONGHELP: Defined when you want long help messages included;
1908 undefine this when you're short of memory.
1910 - CFG_PROMPT: This is what U-Boot prints on the console to
1911 prompt for user input.
1913 - CFG_CBSIZE: Buffer size for input from the Console
1915 - CFG_PBSIZE: Buffer size for Console output
1917 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1919 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1920 the application (usually a Linux kernel) when it is
1923 - CFG_BAUDRATE_TABLE:
1924 List of legal baudrate settings for this board.
1926 - CFG_CONSOLE_INFO_QUIET
1927 Suppress display of console information at boot.
1929 - CFG_CONSOLE_IS_IN_ENV
1930 If the board specific function
1931 extern int overwrite_console (void);
1932 returns 1, the stdin, stderr and stdout are switched to the
1933 serial port, else the settings in the environment are used.
1935 - CFG_CONSOLE_OVERWRITE_ROUTINE
1936 Enable the call to overwrite_console().
1938 - CFG_CONSOLE_ENV_OVERWRITE
1939 Enable overwrite of previous console environment settings.
1941 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1942 Begin and End addresses of the area used by the
1946 Enable an alternate, more extensive memory test.
1948 - CFG_MEMTEST_SCRATCH:
1949 Scratch address used by the alternate memory test
1950 You only need to set this if address zero isn't writeable
1952 - CFG_MEM_TOP_HIDE (PPC only):
1953 If CFG_MEM_TOP_HIDE is defined in the board config header,
1954 this specified memory area will get subtracted from the top
1955 (end) of ram and won't get "touched" at all by U-Boot. By
1956 fixing up gd->ram_size the Linux kernel should gets passed
1957 the now "corrected" memory size and won't touch it either.
1958 This should work for arch/ppc and arch/powerpc. Only Linux
1959 board ports in arch/powerpc with bootwrapper support that
1960 recalculate the memory size from the SDRAM controller setup
1961 will have to get fixed in Linux additionally.
1963 This option can be used as a workaround for the 440EPx/GRx
1964 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1967 WARNING: Please make sure that this value is a multiple of
1968 the Linux page size (normally 4k). If this is not the case,
1969 then the end address of the Linux memory will be located at a
1970 non page size aligned address and this could cause major
1973 - CFG_TFTP_LOADADDR:
1974 Default load address for network file downloads
1976 - CFG_LOADS_BAUD_CHANGE:
1977 Enable temporary baudrate change while serial download
1980 Physical start address of SDRAM. _Must_ be 0 here.
1983 Physical start address of Motherboard I/O (if using a
1987 Physical start address of Flash memory.
1990 Physical start address of boot monitor code (set by
1991 make config files to be same as the text base address
1992 (TEXT_BASE) used when linking) - same as
1993 CFG_FLASH_BASE when booting from flash.
1996 Size of memory reserved for monitor code, used to
1997 determine _at_compile_time_ (!) if the environment is
1998 embedded within the U-Boot image, or in a separate
2002 Size of DRAM reserved for malloc() use.
2005 Normally compressed uImages are limited to an
2006 uncompressed size of 8 MBytes. If this is not enough,
2007 you can define CFG_BOOTM_LEN in your board config file
2008 to adjust this setting to your needs.
2011 Maximum size of memory mapped by the startup code of
2012 the Linux kernel; all data that must be processed by
2013 the Linux kernel (bd_info, boot arguments, FDT blob if
2014 used) must be put below this limit, unless "bootm_low"
2015 enviroment variable is defined and non-zero. In such case
2016 all data for the Linux kernel must be between "bootm_low"
2017 and "bootm_low" + CFG_BOOTMAPSZ.
2019 - CFG_MAX_FLASH_BANKS:
2020 Max number of Flash memory banks
2022 - CFG_MAX_FLASH_SECT:
2023 Max number of sectors on a Flash chip
2025 - CFG_FLASH_ERASE_TOUT:
2026 Timeout for Flash erase operations (in ms)
2028 - CFG_FLASH_WRITE_TOUT:
2029 Timeout for Flash write operations (in ms)
2031 - CFG_FLASH_LOCK_TOUT
2032 Timeout for Flash set sector lock bit operation (in ms)
2034 - CFG_FLASH_UNLOCK_TOUT
2035 Timeout for Flash clear lock bits operation (in ms)
2037 - CFG_FLASH_PROTECTION
2038 If defined, hardware flash sectors protection is used
2039 instead of U-Boot software protection.
2041 - CFG_DIRECT_FLASH_TFTP:
2043 Enable TFTP transfers directly to flash memory;
2044 without this option such a download has to be
2045 performed in two steps: (1) download to RAM, and (2)
2046 copy from RAM to flash.
2048 The two-step approach is usually more reliable, since
2049 you can check if the download worked before you erase
2050 the flash, but in some situations (when sytem RAM is
2051 too limited to allow for a tempory copy of the
2052 downloaded image) this option may be very useful.
2055 Define if the flash driver uses extra elements in the
2056 common flash structure for storing flash geometry.
2058 - CFG_FLASH_CFI_DRIVER
2059 This option also enables the building of the cfi_flash driver
2060 in the drivers directory
2062 - CFG_FLASH_USE_BUFFER_WRITE
2063 Use buffered writes to flash.
2065 - CONFIG_FLASH_SPANSION_S29WS_N
2066 s29ws-n MirrorBit flash has non-standard addresses for buffered
2069 - CFG_FLASH_QUIET_TEST
2070 If this option is defined, the common CFI flash doesn't
2071 print it's warning upon not recognized FLASH banks. This
2072 is useful, if some of the configured banks are only
2073 optionally available.
2075 - CONFIG_FLASH_SHOW_PROGRESS
2076 If defined (must be an integer), print out countdown
2077 digits and dots. Recommended value: 45 (9..1) for 80
2078 column displays, 15 (3..1) for 40 column displays.
2080 - CFG_RX_ETH_BUFFER:
2081 Defines the number of ethernet receive buffers. On some
2082 ethernet controllers it is recommended to set this value
2083 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2084 buffers can be full shortly after enabling the interface
2085 on high ethernet traffic.
2086 Defaults to 4 if not defined.
2088 The following definitions that deal with the placement and management
2089 of environment data (variable area); in general, we support the
2090 following configurations:
2092 - CFG_ENV_IS_IN_FLASH:
2094 Define this if the environment is in flash memory.
2096 a) The environment occupies one whole flash sector, which is
2097 "embedded" in the text segment with the U-Boot code. This
2098 happens usually with "bottom boot sector" or "top boot
2099 sector" type flash chips, which have several smaller
2100 sectors at the start or the end. For instance, such a
2101 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2102 such a case you would place the environment in one of the
2103 4 kB sectors - with U-Boot code before and after it. With
2104 "top boot sector" type flash chips, you would put the
2105 environment in one of the last sectors, leaving a gap
2106 between U-Boot and the environment.
2110 Offset of environment data (variable area) to the
2111 beginning of flash memory; for instance, with bottom boot
2112 type flash chips the second sector can be used: the offset
2113 for this sector is given here.
2115 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2119 This is just another way to specify the start address of
2120 the flash sector containing the environment (instead of
2123 - CFG_ENV_SECT_SIZE:
2125 Size of the sector containing the environment.
2128 b) Sometimes flash chips have few, equal sized, BIG sectors.
2129 In such a case you don't want to spend a whole sector for
2134 If you use this in combination with CFG_ENV_IS_IN_FLASH
2135 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2136 of this flash sector for the environment. This saves
2137 memory for the RAM copy of the environment.
2139 It may also save flash memory if you decide to use this
2140 when your environment is "embedded" within U-Boot code,
2141 since then the remainder of the flash sector could be used
2142 for U-Boot code. It should be pointed out that this is
2143 STRONGLY DISCOURAGED from a robustness point of view:
2144 updating the environment in flash makes it always
2145 necessary to erase the WHOLE sector. If something goes
2146 wrong before the contents has been restored from a copy in
2147 RAM, your target system will be dead.
2149 - CFG_ENV_ADDR_REDUND
2152 These settings describe a second storage area used to hold
2153 a redundand copy of the environment data, so that there is
2154 a valid backup copy in case there is a power failure during
2155 a "saveenv" operation.
2157 BE CAREFUL! Any changes to the flash layout, and some changes to the
2158 source code will make it necessary to adapt <board>/u-boot.lds*
2162 - CFG_ENV_IS_IN_NVRAM:
2164 Define this if you have some non-volatile memory device
2165 (NVRAM, battery buffered SRAM) which you want to use for the
2171 These two #defines are used to determin the memory area you
2172 want to use for environment. It is assumed that this memory
2173 can just be read and written to, without any special
2176 BE CAREFUL! The first access to the environment happens quite early
2177 in U-Boot initalization (when we try to get the setting of for the
2178 console baudrate). You *MUST* have mappend your NVRAM area then, or
2181 Please note that even with NVRAM we still use a copy of the
2182 environment in RAM: we could work on NVRAM directly, but we want to
2183 keep settings there always unmodified except somebody uses "saveenv"
2184 to save the current settings.
2187 - CFG_ENV_IS_IN_EEPROM:
2189 Use this if you have an EEPROM or similar serial access
2190 device and a driver for it.
2195 These two #defines specify the offset and size of the
2196 environment area within the total memory of your EEPROM.
2198 - CFG_I2C_EEPROM_ADDR:
2199 If defined, specified the chip address of the EEPROM device.
2200 The default address is zero.
2202 - CFG_EEPROM_PAGE_WRITE_BITS:
2203 If defined, the number of bits used to address bytes in a
2204 single page in the EEPROM device. A 64 byte page, for example
2205 would require six bits.
2207 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2208 If defined, the number of milliseconds to delay between
2209 page writes. The default is zero milliseconds.
2211 - CFG_I2C_EEPROM_ADDR_LEN:
2212 The length in bytes of the EEPROM memory array address. Note
2213 that this is NOT the chip address length!
2215 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2216 EEPROM chips that implement "address overflow" are ones
2217 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2218 address and the extra bits end up in the "chip address" bit
2219 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2222 Note that we consider the length of the address field to
2223 still be one byte because the extra address bits are hidden
2224 in the chip address.
2227 The size in bytes of the EEPROM device.
2230 - CFG_ENV_IS_IN_DATAFLASH:
2232 Define this if you have a DataFlash memory device which you
2233 want to use for the environment.
2239 These three #defines specify the offset and size of the
2240 environment area within the total memory of your DataFlash placed
2241 at the specified address.
2243 - CFG_ENV_IS_IN_NAND:
2245 Define this if you have a NAND device which you want to use
2246 for the environment.
2251 These two #defines specify the offset and size of the environment
2252 area within the first NAND device.
2254 - CFG_ENV_OFFSET_REDUND
2256 This setting describes a second storage area of CFG_ENV_SIZE
2257 size used to hold a redundant copy of the environment data,
2258 so that there is a valid backup copy in case there is a
2259 power failure during a "saveenv" operation.
2261 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2262 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2263 the NAND devices block size.
2265 - CFG_SPI_INIT_OFFSET
2267 Defines offset to the initial SPI buffer area in DPRAM. The
2268 area is used at an early stage (ROM part) if the environment
2269 is configured to reside in the SPI EEPROM: We need a 520 byte
2270 scratch DPRAM area. It is used between the two initialization
2271 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2272 to be a good choice since it makes it far enough from the
2273 start of the data area as well as from the stack pointer.
2275 Please note that the environment is read-only until the monitor
2276 has been relocated to RAM and a RAM copy of the environment has been
2277 created; also, when using EEPROM you will have to use getenv_r()
2278 until then to read environment variables.
2280 The environment is protected by a CRC32 checksum. Before the monitor
2281 is relocated into RAM, as a result of a bad CRC you will be working
2282 with the compiled-in default environment - *silently*!!! [This is
2283 necessary, because the first environment variable we need is the
2284 "baudrate" setting for the console - if we have a bad CRC, we don't
2285 have any device yet where we could complain.]
2287 Note: once the monitor has been relocated, then it will complain if
2288 the default environment is used; a new CRC is computed as soon as you
2289 use the "saveenv" command to store a valid environment.
2291 - CFG_FAULT_ECHO_LINK_DOWN:
2292 Echo the inverted Ethernet link state to the fault LED.
2294 Note: If this option is active, then CFG_FAULT_MII_ADDR
2295 also needs to be defined.
2297 - CFG_FAULT_MII_ADDR:
2298 MII address of the PHY to check for the Ethernet link state.
2300 - CFG_64BIT_VSPRINTF:
2301 Makes vsprintf (and all *printf functions) support printing
2302 of 64bit values by using the L quantifier
2304 - CFG_64BIT_STRTOUL:
2305 Adds simple_strtoull that returns a 64bit value
2307 Low Level (hardware related) configuration options:
2308 ---------------------------------------------------
2310 - CFG_CACHELINE_SIZE:
2311 Cache Line Size of the CPU.
2314 Default address of the IMMR after system reset.
2316 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2317 and RPXsuper) to be able to adjust the position of
2318 the IMMR register after a reset.
2320 - Floppy Disk Support:
2321 CFG_FDC_DRIVE_NUMBER
2323 the default drive number (default value 0)
2327 defines the spacing between fdc chipset registers
2332 defines the offset of register from address. It
2333 depends on which part of the data bus is connected to
2334 the fdc chipset. (default value 0)
2336 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2337 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2340 if CFG_FDC_HW_INIT is defined, then the function
2341 fdc_hw_init() is called at the beginning of the FDC
2342 setup. fdc_hw_init() must be provided by the board
2343 source code. It is used to make hardware dependant
2346 - CFG_IMMR: Physical address of the Internal Memory.
2347 DO NOT CHANGE unless you know exactly what you're
2348 doing! (11-4) [MPC8xx/82xx systems only]
2350 - CFG_INIT_RAM_ADDR:
2352 Start address of memory area that can be used for
2353 initial data and stack; please note that this must be
2354 writable memory that is working WITHOUT special
2355 initialization, i. e. you CANNOT use normal RAM which
2356 will become available only after programming the
2357 memory controller and running certain initialization
2360 U-Boot uses the following memory types:
2361 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2362 - MPC824X: data cache
2363 - PPC4xx: data cache
2365 - CFG_GBL_DATA_OFFSET:
2367 Offset of the initial data structure in the memory
2368 area defined by CFG_INIT_RAM_ADDR. Usually
2369 CFG_GBL_DATA_OFFSET is chosen such that the initial
2370 data is located at the end of the available space
2371 (sometimes written as (CFG_INIT_RAM_END -
2372 CFG_INIT_DATA_SIZE), and the initial stack is just
2373 below that area (growing from (CFG_INIT_RAM_ADDR +
2374 CFG_GBL_DATA_OFFSET) downward.
2377 On the MPC824X (or other systems that use the data
2378 cache for initial memory) the address chosen for
2379 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2380 point to an otherwise UNUSED address space between
2381 the top of RAM and the start of the PCI space.
2383 - CFG_SIUMCR: SIU Module Configuration (11-6)
2385 - CFG_SYPCR: System Protection Control (11-9)
2387 - CFG_TBSCR: Time Base Status and Control (11-26)
2389 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2391 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2393 - CFG_SCCR: System Clock and reset Control Register (15-27)
2395 - CFG_OR_TIMING_SDRAM:
2399 periodic timer for refresh
2401 - CFG_DER: Debug Event Register (37-47)
2403 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2404 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2405 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2407 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2409 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2410 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2411 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2412 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2414 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2415 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2416 Machine Mode Register and Memory Periodic Timer
2417 Prescaler definitions (SDRAM timing)
2419 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2420 enable I2C microcode relocation patch (MPC8xx);
2421 define relocation offset in DPRAM [DSP2]
2423 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2424 enable SMC microcode relocation patch (MPC8xx);
2425 define relocation offset in DPRAM [SMC1]
2427 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2428 enable SPI microcode relocation patch (MPC8xx);
2429 define relocation offset in DPRAM [SCC4]
2432 Use OSCM clock mode on MBX8xx board. Be careful,
2433 wrong setting might damage your board. Read
2434 doc/README.MBX before setting this variable!
2436 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2437 Offset of the bootmode word in DPRAM used by post
2438 (Power On Self Tests). This definition overrides
2439 #define'd default value in commproc.h resp.
2442 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2443 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2444 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2445 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2446 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2447 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2448 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2449 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2450 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2453 Get DDR timing information from an I2C EEPROM. Common
2454 with pluggable memory modules such as SODIMMs
2457 I2C address of the SPD EEPROM
2460 If SPD EEPROM is on an I2C bus other than the first
2461 one, specify here. Note that the value must resolve
2462 to something your driver can deal with.
2464 - CFG_83XX_DDR_USES_CS0
2465 Only for 83xx systems. If specified, then DDR should
2466 be configured using CS0 and CS1 instead of CS2 and CS3.
2468 - CFG_83XX_DDR_USES_CS0
2469 Only for 83xx systems. If specified, then DDR should
2470 be configured using CS0 and CS1 instead of CS2 and CS3.
2472 - CONFIG_ETHER_ON_FEC[12]
2473 Define to enable FEC[12] on a 8xx series processor.
2475 - CONFIG_FEC[12]_PHY
2476 Define to the hardcoded PHY address which corresponds
2477 to the given FEC; i. e.
2478 #define CONFIG_FEC1_PHY 4
2479 means that the PHY with address 4 is connected to FEC1
2481 When set to -1, means to probe for first available.
2483 - CONFIG_FEC[12]_PHY_NORXERR
2484 The PHY does not have a RXERR line (RMII only).
2485 (so program the FEC to ignore it).
2488 Enable RMII mode for all FECs.
2489 Note that this is a global option, we can't
2490 have one FEC in standard MII mode and another in RMII mode.
2492 - CONFIG_CRC32_VERIFY
2493 Add a verify option to the crc32 command.
2496 => crc32 -v <address> <count> <crc32>
2498 Where address/count indicate a memory area
2499 and crc32 is the correct crc32 which the
2503 Add the "loopw" memory command. This only takes effect if
2504 the memory commands are activated globally (CONFIG_CMD_MEM).
2507 Add the "mdc" and "mwc" memory commands. These are cyclic
2512 This command will print 4 bytes (10,11,12,13) each 500 ms.
2514 => mwc.l 100 12345678 10
2515 This command will write 12345678 to address 100 all 10 ms.
2517 This only takes effect if the memory commands are activated
2518 globally (CONFIG_CMD_MEM).
2520 - CONFIG_SKIP_LOWLEVEL_INIT
2521 - CONFIG_SKIP_RELOCATE_UBOOT
2523 [ARM only] If these variables are defined, then
2524 certain low level initializations (like setting up
2525 the memory controller) are omitted and/or U-Boot does
2526 not relocate itself into RAM.
2527 Normally these variables MUST NOT be defined. The
2528 only exception is when U-Boot is loaded (to RAM) by
2529 some other boot loader or by a debugger which
2530 performs these intializations itself.
2533 Building the Software:
2534 ======================
2536 Building U-Boot has been tested in several native build environments
2537 and in many different cross environments. Of course we cannot support
2538 all possibly existing versions of cross development tools in all
2539 (potentially obsolete) versions. In case of tool chain problems we
2540 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2541 which is extensively used to build and test U-Boot.
2543 If you are not using a native environment, it is assumed that you
2544 have GNU cross compiling tools available in your path. In this case,
2545 you must set the environment variable CROSS_COMPILE in your shell.
2546 Note that no changes to the Makefile or any other source files are
2547 necessary. For example using the ELDK on a 4xx CPU, please enter:
2549 $ CROSS_COMPILE=ppc_4xx-
2550 $ export CROSS_COMPILE
2552 U-Boot is intended to be simple to build. After installing the
2553 sources you must configure U-Boot for one specific board type. This
2558 where "NAME_config" is the name of one of the existing configu-
2559 rations; see the main Makefile for supported names.
2561 Note: for some board special configuration names may exist; check if
2562 additional information is available from the board vendor; for
2563 instance, the TQM823L systems are available without (standard)
2564 or with LCD support. You can select such additional "features"
2565 when chosing the configuration, i. e.
2568 - will configure for a plain TQM823L, i. e. no LCD support
2570 make TQM823L_LCD_config
2571 - will configure for a TQM823L with U-Boot console on LCD
2576 Finally, type "make all", and you should get some working U-Boot
2577 images ready for download to / installation on your system:
2579 - "u-boot.bin" is a raw binary image
2580 - "u-boot" is an image in ELF binary format
2581 - "u-boot.srec" is in Motorola S-Record format
2583 By default the build is performed locally and the objects are saved
2584 in the source directory. One of the two methods can be used to change
2585 this behavior and build U-Boot to some external directory:
2587 1. Add O= to the make command line invocations:
2589 make O=/tmp/build distclean
2590 make O=/tmp/build NAME_config
2591 make O=/tmp/build all
2593 2. Set environment variable BUILD_DIR to point to the desired location:
2595 export BUILD_DIR=/tmp/build
2600 Note that the command line "O=" setting overrides the BUILD_DIR environment
2604 Please be aware that the Makefiles assume you are using GNU make, so
2605 for instance on NetBSD you might need to use "gmake" instead of
2609 If the system board that you have is not listed, then you will need
2610 to port U-Boot to your hardware platform. To do this, follow these
2613 1. Add a new configuration option for your board to the toplevel
2614 "Makefile" and to the "MAKEALL" script, using the existing
2615 entries as examples. Note that here and at many other places
2616 boards and other names are listed in alphabetical sort order. Please
2618 2. Create a new directory to hold your board specific code. Add any
2619 files you need. In your board directory, you will need at least
2620 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2621 3. Create a new configuration file "include/configs/<board>.h" for
2623 3. If you're porting U-Boot to a new CPU, then also create a new
2624 directory to hold your CPU specific code. Add any files you need.
2625 4. Run "make <board>_config" with your new name.
2626 5. Type "make", and you should get a working "u-boot.srec" file
2627 to be installed on your target system.
2628 6. Debug and solve any problems that might arise.
2629 [Of course, this last step is much harder than it sounds.]
2632 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2633 ==============================================================
2635 If you have modified U-Boot sources (for instance added a new board
2636 or support for new devices, a new CPU, etc.) you are expected to
2637 provide feedback to the other developers. The feedback normally takes
2638 the form of a "patch", i. e. a context diff against a certain (latest
2639 official or latest in the git repository) version of U-Boot sources.
2641 But before you submit such a patch, please verify that your modifi-
2642 cation did not break existing code. At least make sure that *ALL* of
2643 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2644 just run the "MAKEALL" script, which will configure and build U-Boot
2645 for ALL supported system. Be warned, this will take a while. You can
2646 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2647 environment variable to the script, i. e. to use the ELDK cross tools
2650 CROSS_COMPILE=ppc_8xx- MAKEALL
2652 or to build on a native PowerPC system you can type
2654 CROSS_COMPILE=' ' MAKEALL
2656 When using the MAKEALL script, the default behaviour is to build
2657 U-Boot in the source directory. This location can be changed by
2658 setting the BUILD_DIR environment variable. Also, for each target
2659 built, the MAKEALL script saves two log files (<target>.ERR and
2660 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2661 location can be changed by setting the MAKEALL_LOGDIR environment
2662 variable. For example:
2664 export BUILD_DIR=/tmp/build
2665 export MAKEALL_LOGDIR=/tmp/log
2666 CROSS_COMPILE=ppc_8xx- MAKEALL
2668 With the above settings build objects are saved in the /tmp/build,
2669 log files are saved in the /tmp/log and the source tree remains clean
2670 during the whole build process.
2673 See also "U-Boot Porting Guide" below.
2676 Monitor Commands - Overview:
2677 ============================
2679 go - start application at address 'addr'
2680 run - run commands in an environment variable
2681 bootm - boot application image from memory
2682 bootp - boot image via network using BootP/TFTP protocol
2683 tftpboot- boot image via network using TFTP protocol
2684 and env variables "ipaddr" and "serverip"
2685 (and eventually "gatewayip")
2686 rarpboot- boot image via network using RARP/TFTP protocol
2687 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2688 loads - load S-Record file over serial line
2689 loadb - load binary file over serial line (kermit mode)
2691 mm - memory modify (auto-incrementing)
2692 nm - memory modify (constant address)
2693 mw - memory write (fill)
2695 cmp - memory compare
2696 crc32 - checksum calculation
2697 imd - i2c memory display
2698 imm - i2c memory modify (auto-incrementing)
2699 inm - i2c memory modify (constant address)
2700 imw - i2c memory write (fill)
2701 icrc32 - i2c checksum calculation
2702 iprobe - probe to discover valid I2C chip addresses
2703 iloop - infinite loop on address range
2704 isdram - print SDRAM configuration information
2705 sspi - SPI utility commands
2706 base - print or set address offset
2707 printenv- print environment variables
2708 setenv - set environment variables
2709 saveenv - save environment variables to persistent storage
2710 protect - enable or disable FLASH write protection
2711 erase - erase FLASH memory
2712 flinfo - print FLASH memory information
2713 bdinfo - print Board Info structure
2714 iminfo - print header information for application image
2715 coninfo - print console devices and informations
2716 ide - IDE sub-system
2717 loop - infinite loop on address range
2718 loopw - infinite write loop on address range
2719 mtest - simple RAM test
2720 icache - enable or disable instruction cache
2721 dcache - enable or disable data cache
2722 reset - Perform RESET of the CPU
2723 echo - echo args to console
2724 version - print monitor version
2725 help - print online help
2726 ? - alias for 'help'
2729 Monitor Commands - Detailed Description:
2730 ========================================
2734 For now: just type "help <command>".
2737 Environment Variables:
2738 ======================
2740 U-Boot supports user configuration using Environment Variables which
2741 can be made persistent by saving to Flash memory.
2743 Environment Variables are set using "setenv", printed using
2744 "printenv", and saved to Flash using "saveenv". Using "setenv"
2745 without a value can be used to delete a variable from the
2746 environment. As long as you don't save the environment you are
2747 working with an in-memory copy. In case the Flash area containing the
2748 environment is erased by accident, a default environment is provided.
2750 Some configuration options can be set using Environment Variables:
2752 baudrate - see CONFIG_BAUDRATE
2754 bootdelay - see CONFIG_BOOTDELAY
2756 bootcmd - see CONFIG_BOOTCOMMAND
2758 bootargs - Boot arguments when booting an RTOS image
2760 bootfile - Name of the image to load with TFTP
2762 bootm_low - Memory range available for image processing in the bootm
2763 command can be restricted. This variable is given as
2764 a hexadecimal number and defines lowest address allowed
2765 for use by the bootm command. See also "bootm_size"
2766 environment variable. Address defined by "bootm_low" is
2767 also the base of the initial memory mapping for the Linux
2768 kernel -- see the descripton of CFG_BOOTMAPSZ.
2770 bootm_size - Memory range available for image processing in the bootm
2771 command can be restricted. This variable is given as
2772 a hexadecimal number and defines the size of the region
2773 allowed for use by the bootm command. See also "bootm_low"
2774 environment variable.
2776 autoload - if set to "no" (any string beginning with 'n'),
2777 "bootp" will just load perform a lookup of the
2778 configuration from the BOOTP server, but not try to
2779 load any image using TFTP
2781 autoscript - if set to "yes" commands like "loadb", "loady",
2782 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2783 to automatically run script images (by internally
2784 calling "autoscript").
2786 autoscript_uname - if script image is in a format (FIT) this
2787 variable is used to get script subimage unit name.
2789 autostart - if set to "yes", an image loaded using the "bootp",
2790 "rarpboot", "tftpboot" or "diskboot" commands will
2791 be automatically started (by internally calling
2794 If set to "no", a standalone image passed to the
2795 "bootm" command will be copied to the load address
2796 (and eventually uncompressed), but NOT be started.
2797 This can be used to load and uncompress arbitrary
2800 i2cfast - (PPC405GP|PPC405EP only)
2801 if set to 'y' configures Linux I2C driver for fast
2802 mode (400kHZ). This environment variable is used in
2803 initialization code. So, for changes to be effective
2804 it must be saved and board must be reset.
2806 initrd_high - restrict positioning of initrd images:
2807 If this variable is not set, initrd images will be
2808 copied to the highest possible address in RAM; this
2809 is usually what you want since it allows for
2810 maximum initrd size. If for some reason you want to
2811 make sure that the initrd image is loaded below the
2812 CFG_BOOTMAPSZ limit, you can set this environment
2813 variable to a value of "no" or "off" or "0".
2814 Alternatively, you can set it to a maximum upper
2815 address to use (U-Boot will still check that it
2816 does not overwrite the U-Boot stack and data).
2818 For instance, when you have a system with 16 MB
2819 RAM, and want to reserve 4 MB from use by Linux,
2820 you can do this by adding "mem=12M" to the value of
2821 the "bootargs" variable. However, now you must make
2822 sure that the initrd image is placed in the first
2823 12 MB as well - this can be done with
2825 setenv initrd_high 00c00000
2827 If you set initrd_high to 0xFFFFFFFF, this is an
2828 indication to U-Boot that all addresses are legal
2829 for the Linux kernel, including addresses in flash
2830 memory. In this case U-Boot will NOT COPY the
2831 ramdisk at all. This may be useful to reduce the
2832 boot time on your system, but requires that this
2833 feature is supported by your Linux kernel.
2835 ipaddr - IP address; needed for tftpboot command
2837 loadaddr - Default load address for commands like "bootp",
2838 "rarpboot", "tftpboot", "loadb" or "diskboot"
2840 loads_echo - see CONFIG_LOADS_ECHO
2842 serverip - TFTP server IP address; needed for tftpboot command
2844 bootretry - see CONFIG_BOOT_RETRY_TIME
2846 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2848 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2850 ethprime - When CONFIG_NET_MULTI is enabled controls which
2851 interface is used first.
2853 ethact - When CONFIG_NET_MULTI is enabled controls which
2854 interface is currently active. For example you
2855 can do the following
2857 => setenv ethact FEC ETHERNET
2858 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2859 => setenv ethact SCC ETHERNET
2860 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2862 ethrotate - When set to "no" U-Boot does not go through all
2863 available network interfaces.
2864 It just stays at the currently selected interface.
2866 netretry - When set to "no" each network operation will
2867 either succeed or fail without retrying.
2868 When set to "once" the network operation will
2869 fail when all the available network interfaces
2870 are tried once without success.
2871 Useful on scripts which control the retry operation
2874 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2875 if set load address for the npe microcode
2877 tftpsrcport - If this is set, the value is used for TFTP's
2880 tftpdstport - If this is set, the value is used for TFTP's UDP
2881 destination port instead of the Well Know Port 69.
2883 vlan - When set to a value < 4095 the traffic over
2884 ethernet is encapsulated/received over 802.1q
2887 The following environment variables may be used and automatically
2888 updated by the network boot commands ("bootp" and "rarpboot"),
2889 depending the information provided by your boot server:
2891 bootfile - see above
2892 dnsip - IP address of your Domain Name Server
2893 dnsip2 - IP address of your secondary Domain Name Server
2894 gatewayip - IP address of the Gateway (Router) to use
2895 hostname - Target hostname
2897 netmask - Subnet Mask
2898 rootpath - Pathname of the root filesystem on the NFS server
2899 serverip - see above
2902 There are two special Environment Variables:
2904 serial# - contains hardware identification information such
2905 as type string and/or serial number
2906 ethaddr - Ethernet address
2908 These variables can be set only once (usually during manufacturing of
2909 the board). U-Boot refuses to delete or overwrite these variables
2910 once they have been set once.
2913 Further special Environment Variables:
2915 ver - Contains the U-Boot version string as printed
2916 with the "version" command. This variable is
2917 readonly (see CONFIG_VERSION_VARIABLE).
2920 Please note that changes to some configuration parameters may take
2921 only effect after the next boot (yes, that's just like Windoze :-).
2924 Command Line Parsing:
2925 =====================
2927 There are two different command line parsers available with U-Boot:
2928 the old "simple" one, and the much more powerful "hush" shell:
2930 Old, simple command line parser:
2931 --------------------------------
2933 - supports environment variables (through setenv / saveenv commands)
2934 - several commands on one line, separated by ';'
2935 - variable substitution using "... ${name} ..." syntax
2936 - special characters ('$', ';') can be escaped by prefixing with '\',
2938 setenv bootcmd bootm \${address}
2939 - You can also escape text by enclosing in single apostrophes, for example:
2940 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2945 - similar to Bourne shell, with control structures like
2946 if...then...else...fi, for...do...done; while...do...done,
2947 until...do...done, ...
2948 - supports environment ("global") variables (through setenv / saveenv
2949 commands) and local shell variables (through standard shell syntax
2950 "name=value"); only environment variables can be used with "run"
2956 (1) If a command line (or an environment variable executed by a "run"
2957 command) contains several commands separated by semicolon, and
2958 one of these commands fails, then the remaining commands will be
2961 (2) If you execute several variables with one call to run (i. e.
2962 calling run with a list af variables as arguments), any failing
2963 command will cause "run" to terminate, i. e. the remaining
2964 variables are not executed.
2966 Note for Redundant Ethernet Interfaces:
2967 =======================================
2969 Some boards come with redundant ethernet interfaces; U-Boot supports
2970 such configurations and is capable of automatic selection of a
2971 "working" interface when needed. MAC assignment works as follows:
2973 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2974 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2975 "eth1addr" (=>eth1), "eth2addr", ...
2977 If the network interface stores some valid MAC address (for instance
2978 in SROM), this is used as default address if there is NO correspon-
2979 ding setting in the environment; if the corresponding environment
2980 variable is set, this overrides the settings in the card; that means:
2982 o If the SROM has a valid MAC address, and there is no address in the
2983 environment, the SROM's address is used.
2985 o If there is no valid address in the SROM, and a definition in the
2986 environment exists, then the value from the environment variable is
2989 o If both the SROM and the environment contain a MAC address, and
2990 both addresses are the same, this MAC address is used.
2992 o If both the SROM and the environment contain a MAC address, and the
2993 addresses differ, the value from the environment is used and a
2996 o If neither SROM nor the environment contain a MAC address, an error
3003 U-Boot is capable of booting (and performing other auxiliary operations on)
3004 images in two formats:
3006 New uImage format (FIT)
3007 -----------------------
3009 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3010 to Flattened Device Tree). It allows the use of images with multiple
3011 components (several kernels, ramdisks, etc.), with contents protected by
3012 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3018 Old image format is based on binary files which can be basically anything,
3019 preceded by a special header; see the definitions in include/image.h for
3020 details; basically, the header defines the following image properties:
3022 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3023 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3024 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3025 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3026 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3027 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3028 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3029 * Compression Type (uncompressed, gzip, bzip2)
3035 The header is marked by a special Magic Number, and both the header
3036 and the data portions of the image are secured against corruption by
3043 Although U-Boot should support any OS or standalone application
3044 easily, the main focus has always been on Linux during the design of
3047 U-Boot includes many features that so far have been part of some
3048 special "boot loader" code within the Linux kernel. Also, any
3049 "initrd" images to be used are no longer part of one big Linux image;
3050 instead, kernel and "initrd" are separate images. This implementation
3051 serves several purposes:
3053 - the same features can be used for other OS or standalone
3054 applications (for instance: using compressed images to reduce the
3055 Flash memory footprint)
3057 - it becomes much easier to port new Linux kernel versions because
3058 lots of low-level, hardware dependent stuff are done by U-Boot
3060 - the same Linux kernel image can now be used with different "initrd"
3061 images; of course this also means that different kernel images can
3062 be run with the same "initrd". This makes testing easier (you don't
3063 have to build a new "zImage.initrd" Linux image when you just
3064 change a file in your "initrd"). Also, a field-upgrade of the
3065 software is easier now.
3071 Porting Linux to U-Boot based systems:
3072 ---------------------------------------
3074 U-Boot cannot save you from doing all the necessary modifications to
3075 configure the Linux device drivers for use with your target hardware
3076 (no, we don't intend to provide a full virtual machine interface to
3079 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3081 Just make sure your machine specific header file (for instance
3082 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3083 Information structure as we define in include/u-boot.h, and make
3084 sure that your definition of IMAP_ADDR uses the same value as your
3085 U-Boot configuration in CFG_IMMR.
3088 Configuring the Linux kernel:
3089 -----------------------------
3091 No specific requirements for U-Boot. Make sure you have some root
3092 device (initial ramdisk, NFS) for your target system.
3095 Building a Linux Image:
3096 -----------------------
3098 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3099 not used. If you use recent kernel source, a new build target
3100 "uImage" will exist which automatically builds an image usable by
3101 U-Boot. Most older kernels also have support for a "pImage" target,
3102 which was introduced for our predecessor project PPCBoot and uses a
3103 100% compatible format.
3112 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3113 encapsulate a compressed Linux kernel image with header information,
3114 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3116 * build a standard "vmlinux" kernel image (in ELF binary format):
3118 * convert the kernel into a raw binary image:
3120 ${CROSS_COMPILE}-objcopy -O binary \
3121 -R .note -R .comment \
3122 -S vmlinux linux.bin
3124 * compress the binary image:
3128 * package compressed binary image for U-Boot:
3130 mkimage -A ppc -O linux -T kernel -C gzip \
3131 -a 0 -e 0 -n "Linux Kernel Image" \
3132 -d linux.bin.gz uImage
3135 The "mkimage" tool can also be used to create ramdisk images for use
3136 with U-Boot, either separated from the Linux kernel image, or
3137 combined into one file. "mkimage" encapsulates the images with a 64
3138 byte header containing information about target architecture,
3139 operating system, image type, compression method, entry points, time
3140 stamp, CRC32 checksums, etc.
3142 "mkimage" can be called in two ways: to verify existing images and
3143 print the header information, or to build new images.
3145 In the first form (with "-l" option) mkimage lists the information
3146 contained in the header of an existing U-Boot image; this includes
3147 checksum verification:
3149 tools/mkimage -l image
3150 -l ==> list image header information
3152 The second form (with "-d" option) is used to build a U-Boot image
3153 from a "data file" which is used as image payload:
3155 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3156 -n name -d data_file image
3157 -A ==> set architecture to 'arch'
3158 -O ==> set operating system to 'os'
3159 -T ==> set image type to 'type'
3160 -C ==> set compression type 'comp'
3161 -a ==> set load address to 'addr' (hex)
3162 -e ==> set entry point to 'ep' (hex)
3163 -n ==> set image name to 'name'
3164 -d ==> use image data from 'datafile'
3166 Right now, all Linux kernels for PowerPC systems use the same load
3167 address (0x00000000), but the entry point address depends on the
3170 - 2.2.x kernels have the entry point at 0x0000000C,
3171 - 2.3.x and later kernels have the entry point at 0x00000000.
3173 So a typical call to build a U-Boot image would read:
3175 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3176 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3177 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3178 > examples/uImage.TQM850L
3179 Image Name: 2.4.4 kernel for TQM850L
3180 Created: Wed Jul 19 02:34:59 2000
3181 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3182 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3183 Load Address: 0x00000000
3184 Entry Point: 0x00000000
3186 To verify the contents of the image (or check for corruption):
3188 -> tools/mkimage -l examples/uImage.TQM850L
3189 Image Name: 2.4.4 kernel for TQM850L
3190 Created: Wed Jul 19 02:34:59 2000
3191 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3192 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3193 Load Address: 0x00000000
3194 Entry Point: 0x00000000
3196 NOTE: for embedded systems where boot time is critical you can trade
3197 speed for memory and install an UNCOMPRESSED image instead: this
3198 needs more space in Flash, but boots much faster since it does not
3199 need to be uncompressed:
3201 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3202 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3203 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3204 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3205 > examples/uImage.TQM850L-uncompressed
3206 Image Name: 2.4.4 kernel for TQM850L
3207 Created: Wed Jul 19 02:34:59 2000
3208 Image Type: PowerPC Linux Kernel Image (uncompressed)
3209 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3210 Load Address: 0x00000000
3211 Entry Point: 0x00000000
3214 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3215 when your kernel is intended to use an initial ramdisk:
3217 -> tools/mkimage -n 'Simple Ramdisk Image' \
3218 > -A ppc -O linux -T ramdisk -C gzip \
3219 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3220 Image Name: Simple Ramdisk Image
3221 Created: Wed Jan 12 14:01:50 2000
3222 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3223 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3224 Load Address: 0x00000000
3225 Entry Point: 0x00000000
3228 Installing a Linux Image:
3229 -------------------------
3231 To downloading a U-Boot image over the serial (console) interface,
3232 you must convert the image to S-Record format:
3234 objcopy -I binary -O srec examples/image examples/image.srec
3236 The 'objcopy' does not understand the information in the U-Boot
3237 image header, so the resulting S-Record file will be relative to
3238 address 0x00000000. To load it to a given address, you need to
3239 specify the target address as 'offset' parameter with the 'loads'
3242 Example: install the image to address 0x40100000 (which on the
3243 TQM8xxL is in the first Flash bank):
3245 => erase 40100000 401FFFFF
3251 ## Ready for S-Record download ...
3252 ~>examples/image.srec
3253 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3255 15989 15990 15991 15992
3256 [file transfer complete]
3258 ## Start Addr = 0x00000000
3261 You can check the success of the download using the 'iminfo' command;
3262 this includes a checksum verification so you can be sure no data
3263 corruption happened:
3267 ## Checking Image at 40100000 ...
3268 Image Name: 2.2.13 for initrd on TQM850L
3269 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3270 Data Size: 335725 Bytes = 327 kB = 0 MB
3271 Load Address: 00000000
3272 Entry Point: 0000000c
3273 Verifying Checksum ... OK
3279 The "bootm" command is used to boot an application that is stored in
3280 memory (RAM or Flash). In case of a Linux kernel image, the contents
3281 of the "bootargs" environment variable is passed to the kernel as
3282 parameters. You can check and modify this variable using the
3283 "printenv" and "setenv" commands:
3286 => printenv bootargs
3287 bootargs=root=/dev/ram
3289 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3291 => printenv bootargs
3292 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3295 ## Booting Linux kernel at 40020000 ...
3296 Image Name: 2.2.13 for NFS on TQM850L
3297 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3298 Data Size: 381681 Bytes = 372 kB = 0 MB
3299 Load Address: 00000000
3300 Entry Point: 0000000c
3301 Verifying Checksum ... OK
3302 Uncompressing Kernel Image ... OK
3303 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
3304 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3305 time_init: decrementer frequency = 187500000/60
3306 Calibrating delay loop... 49.77 BogoMIPS
3307 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3310 If you want to boot a Linux kernel with initial ram disk, you pass
3311 the memory addresses of both the kernel and the initrd image (PPBCOOT
3312 format!) to the "bootm" command:
3314 => imi 40100000 40200000
3316 ## Checking Image at 40100000 ...
3317 Image Name: 2.2.13 for initrd on TQM850L
3318 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3319 Data Size: 335725 Bytes = 327 kB = 0 MB
3320 Load Address: 00000000
3321 Entry Point: 0000000c
3322 Verifying Checksum ... OK
3324 ## Checking Image at 40200000 ...
3325 Image Name: Simple Ramdisk Image
3326 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3327 Data Size: 566530 Bytes = 553 kB = 0 MB
3328 Load Address: 00000000
3329 Entry Point: 00000000
3330 Verifying Checksum ... OK
3332 => bootm 40100000 40200000
3333 ## Booting Linux kernel at 40100000 ...
3334 Image Name: 2.2.13 for initrd on TQM850L
3335 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3336 Data Size: 335725 Bytes = 327 kB = 0 MB
3337 Load Address: 00000000
3338 Entry Point: 0000000c
3339 Verifying Checksum ... OK
3340 Uncompressing Kernel Image ... OK
3341 ## Loading RAMDisk Image at 40200000 ...
3342 Image Name: Simple Ramdisk Image
3343 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3344 Data Size: 566530 Bytes = 553 kB = 0 MB
3345 Load Address: 00000000
3346 Entry Point: 00000000
3347 Verifying Checksum ... OK
3348 Loading Ramdisk ... OK
3349 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
3350 Boot arguments: root=/dev/ram
3351 time_init: decrementer frequency = 187500000/60
3352 Calibrating delay loop... 49.77 BogoMIPS
3354 RAMDISK: Compressed image found at block 0
3355 VFS: Mounted root (ext2 filesystem).
3359 Boot Linux and pass a flat device tree:
3362 First, U-Boot must be compiled with the appropriate defines. See the section
3363 titled "Linux Kernel Interface" above for a more in depth explanation. The
3364 following is an example of how to start a kernel and pass an updated
3370 oft=oftrees/mpc8540ads.dtb
3371 => tftp $oftaddr $oft
3372 Speed: 1000, full duplex
3374 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3375 Filename 'oftrees/mpc8540ads.dtb'.
3376 Load address: 0x300000
3379 Bytes transferred = 4106 (100a hex)
3380 => tftp $loadaddr $bootfile
3381 Speed: 1000, full duplex
3383 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3385 Load address: 0x200000
3386 Loading:############
3388 Bytes transferred = 1029407 (fb51f hex)
3393 => bootm $loadaddr - $oftaddr
3394 ## Booting image at 00200000 ...
3395 Image Name: Linux-2.6.17-dirty
3396 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3397 Data Size: 1029343 Bytes = 1005.2 kB
3398 Load Address: 00000000
3399 Entry Point: 00000000
3400 Verifying Checksum ... OK
3401 Uncompressing Kernel Image ... OK
3402 Booting using flat device tree at 0x300000
3403 Using MPC85xx ADS machine description
3404 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3408 More About U-Boot Image Types:
3409 ------------------------------
3411 U-Boot supports the following image types:
3413 "Standalone Programs" are directly runnable in the environment
3414 provided by U-Boot; it is expected that (if they behave
3415 well) you can continue to work in U-Boot after return from
3416 the Standalone Program.
3417 "OS Kernel Images" are usually images of some Embedded OS which
3418 will take over control completely. Usually these programs
3419 will install their own set of exception handlers, device
3420 drivers, set up the MMU, etc. - this means, that you cannot
3421 expect to re-enter U-Boot except by resetting the CPU.
3422 "RAMDisk Images" are more or less just data blocks, and their
3423 parameters (address, size) are passed to an OS kernel that is
3425 "Multi-File Images" contain several images, typically an OS
3426 (Linux) kernel image and one or more data images like
3427 RAMDisks. This construct is useful for instance when you want
3428 to boot over the network using BOOTP etc., where the boot
3429 server provides just a single image file, but you want to get
3430 for instance an OS kernel and a RAMDisk image.
3432 "Multi-File Images" start with a list of image sizes, each
3433 image size (in bytes) specified by an "uint32_t" in network
3434 byte order. This list is terminated by an "(uint32_t)0".
3435 Immediately after the terminating 0 follow the images, one by
3436 one, all aligned on "uint32_t" boundaries (size rounded up to
3437 a multiple of 4 bytes).
3439 "Firmware Images" are binary images containing firmware (like
3440 U-Boot or FPGA images) which usually will be programmed to
3443 "Script files" are command sequences that will be executed by
3444 U-Boot's command interpreter; this feature is especially
3445 useful when you configure U-Boot to use a real shell (hush)
3446 as command interpreter.
3452 One of the features of U-Boot is that you can dynamically load and
3453 run "standalone" applications, which can use some resources of
3454 U-Boot like console I/O functions or interrupt services.
3456 Two simple examples are included with the sources:
3461 'examples/hello_world.c' contains a small "Hello World" Demo
3462 application; it is automatically compiled when you build U-Boot.
3463 It's configured to run at address 0x00040004, so you can play with it
3467 ## Ready for S-Record download ...
3468 ~>examples/hello_world.srec
3469 1 2 3 4 5 6 7 8 9 10 11 ...
3470 [file transfer complete]
3472 ## Start Addr = 0x00040004
3474 => go 40004 Hello World! This is a test.
3475 ## Starting application at 0x00040004 ...
3486 Hit any key to exit ...
3488 ## Application terminated, rc = 0x0
3490 Another example, which demonstrates how to register a CPM interrupt
3491 handler with the U-Boot code, can be found in 'examples/timer.c'.
3492 Here, a CPM timer is set up to generate an interrupt every second.
3493 The interrupt service routine is trivial, just printing a '.'
3494 character, but this is just a demo program. The application can be
3495 controlled by the following keys:
3497 ? - print current values og the CPM Timer registers
3498 b - enable interrupts and start timer
3499 e - stop timer and disable interrupts
3500 q - quit application
3503 ## Ready for S-Record download ...
3504 ~>examples/timer.srec
3505 1 2 3 4 5 6 7 8 9 10 11 ...
3506 [file transfer complete]
3508 ## Start Addr = 0x00040004
3511 ## Starting application at 0x00040004 ...
3514 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3517 [q, b, e, ?] Set interval 1000000 us
3520 [q, b, e, ?] ........
3521 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3524 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3527 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3530 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3532 [q, b, e, ?] ...Stopping timer
3534 [q, b, e, ?] ## Application terminated, rc = 0x0
3540 Over time, many people have reported problems when trying to use the
3541 "minicom" terminal emulation program for serial download. I (wd)
3542 consider minicom to be broken, and recommend not to use it. Under
3543 Unix, I recommend to use C-Kermit for general purpose use (and
3544 especially for kermit binary protocol download ("loadb" command), and
3545 use "cu" for S-Record download ("loads" command).
3547 Nevertheless, if you absolutely want to use it try adding this
3548 configuration to your "File transfer protocols" section:
3550 Name Program Name U/D FullScr IO-Red. Multi
3551 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3552 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3558 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3559 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3561 Building requires a cross environment; it is known to work on
3562 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3563 need gmake since the Makefiles are not compatible with BSD make).
3564 Note that the cross-powerpc package does not install include files;
3565 attempting to build U-Boot will fail because <machine/ansi.h> is
3566 missing. This file has to be installed and patched manually:
3568 # cd /usr/pkg/cross/powerpc-netbsd/include
3570 # ln -s powerpc machine
3571 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3572 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3574 Native builds *don't* work due to incompatibilities between native
3575 and U-Boot include files.
3577 Booting assumes that (the first part of) the image booted is a
3578 stage-2 loader which in turn loads and then invokes the kernel
3579 proper. Loader sources will eventually appear in the NetBSD source
3580 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3581 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3584 Implementation Internals:
3585 =========================
3587 The following is not intended to be a complete description of every
3588 implementation detail. However, it should help to understand the
3589 inner workings of U-Boot and make it easier to port it to custom
3593 Initial Stack, Global Data:
3594 ---------------------------
3596 The implementation of U-Boot is complicated by the fact that U-Boot
3597 starts running out of ROM (flash memory), usually without access to
3598 system RAM (because the memory controller is not initialized yet).
3599 This means that we don't have writable Data or BSS segments, and BSS
3600 is not initialized as zero. To be able to get a C environment working
3601 at all, we have to allocate at least a minimal stack. Implementation
3602 options for this are defined and restricted by the CPU used: Some CPU
3603 models provide on-chip memory (like the IMMR area on MPC8xx and
3604 MPC826x processors), on others (parts of) the data cache can be
3605 locked as (mis-) used as memory, etc.
3607 Chris Hallinan posted a good summary of these issues to the
3608 u-boot-users mailing list:
3610 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3611 From: "Chris Hallinan" <clh@net1plus.com>
3612 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3615 Correct me if I'm wrong, folks, but the way I understand it
3616 is this: Using DCACHE as initial RAM for Stack, etc, does not
3617 require any physical RAM backing up the cache. The cleverness
3618 is that the cache is being used as a temporary supply of
3619 necessary storage before the SDRAM controller is setup. It's
3620 beyond the scope of this list to expain the details, but you
3621 can see how this works by studying the cache architecture and
3622 operation in the architecture and processor-specific manuals.
3624 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3625 is another option for the system designer to use as an
3626 initial stack/ram area prior to SDRAM being available. Either
3627 option should work for you. Using CS 4 should be fine if your
3628 board designers haven't used it for something that would
3629 cause you grief during the initial boot! It is frequently not
3632 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3633 with your processor/board/system design. The default value
3634 you will find in any recent u-boot distribution in
3635 walnut.h should work for you. I'd set it to a value larger
3636 than your SDRAM module. If you have a 64MB SDRAM module, set
3637 it above 400_0000. Just make sure your board has no resources
3638 that are supposed to respond to that address! That code in
3639 start.S has been around a while and should work as is when
3640 you get the config right.
3645 It is essential to remember this, since it has some impact on the C
3646 code for the initialization procedures:
3648 * Initialized global data (data segment) is read-only. Do not attempt
3651 * Do not use any unitialized global data (or implicitely initialized
3652 as zero data - BSS segment) at all - this is undefined, initiali-
3653 zation is performed later (when relocating to RAM).
3655 * Stack space is very limited. Avoid big data buffers or things like
3658 Having only the stack as writable memory limits means we cannot use
3659 normal global data to share information beween the code. But it
3660 turned out that the implementation of U-Boot can be greatly
3661 simplified by making a global data structure (gd_t) available to all
3662 functions. We could pass a pointer to this data as argument to _all_
3663 functions, but this would bloat the code. Instead we use a feature of
3664 the GCC compiler (Global Register Variables) to share the data: we
3665 place a pointer (gd) to the global data into a register which we
3666 reserve for this purpose.
3668 When choosing a register for such a purpose we are restricted by the
3669 relevant (E)ABI specifications for the current architecture, and by
3670 GCC's implementation.
3672 For PowerPC, the following registers have specific use:
3674 R2: reserved for system use
3675 R3-R4: parameter passing and return values
3676 R5-R10: parameter passing
3677 R13: small data area pointer
3681 (U-Boot also uses R14 as internal GOT pointer.)
3683 ==> U-Boot will use R2 to hold a pointer to the global data
3685 Note: on PPC, we could use a static initializer (since the
3686 address of the global data structure is known at compile time),
3687 but it turned out that reserving a register results in somewhat
3688 smaller code - although the code savings are not that big (on
3689 average for all boards 752 bytes for the whole U-Boot image,
3690 624 text + 127 data).
3692 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3693 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3695 ==> U-Boot will use P5 to hold a pointer to the global data
3697 On ARM, the following registers are used:
3699 R0: function argument word/integer result
3700 R1-R3: function argument word
3702 R10: stack limit (used only if stack checking if enabled)
3703 R11: argument (frame) pointer
3704 R12: temporary workspace
3707 R15: program counter
3709 ==> U-Boot will use R8 to hold a pointer to the global data
3711 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3712 or current versions of GCC may "optimize" the code too much.
3717 U-Boot runs in system state and uses physical addresses, i.e. the
3718 MMU is not used either for address mapping nor for memory protection.
3720 The available memory is mapped to fixed addresses using the memory
3721 controller. In this process, a contiguous block is formed for each
3722 memory type (Flash, SDRAM, SRAM), even when it consists of several
3723 physical memory banks.
3725 U-Boot is installed in the first 128 kB of the first Flash bank (on
3726 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3727 booting and sizing and initializing DRAM, the code relocates itself
3728 to the upper end of DRAM. Immediately below the U-Boot code some
3729 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3730 configuration setting]. Below that, a structure with global Board
3731 Info data is placed, followed by the stack (growing downward).
3733 Additionally, some exception handler code is copied to the low 8 kB
3734 of DRAM (0x00000000 ... 0x00001FFF).
3736 So a typical memory configuration with 16 MB of DRAM could look like
3739 0x0000 0000 Exception Vector code
3742 0x0000 2000 Free for Application Use
3748 0x00FB FF20 Monitor Stack (Growing downward)
3749 0x00FB FFAC Board Info Data and permanent copy of global data
3750 0x00FC 0000 Malloc Arena
3753 0x00FE 0000 RAM Copy of Monitor Code
3754 ... eventually: LCD or video framebuffer
3755 ... eventually: pRAM (Protected RAM - unchanged by reset)
3756 0x00FF FFFF [End of RAM]
3759 System Initialization:
3760 ----------------------
3762 In the reset configuration, U-Boot starts at the reset entry point
3763 (on most PowerPC systens at address 0x00000100). Because of the reset
3764 configuration for CS0# this is a mirror of the onboard Flash memory.
3765 To be able to re-map memory U-Boot then jumps to its link address.
3766 To be able to implement the initialization code in C, a (small!)
3767 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3768 which provide such a feature like MPC8xx or MPC8260), or in a locked
3769 part of the data cache. After that, U-Boot initializes the CPU core,
3770 the caches and the SIU.
3772 Next, all (potentially) available memory banks are mapped using a
3773 preliminary mapping. For example, we put them on 512 MB boundaries
3774 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3775 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3776 programmed for SDRAM access. Using the temporary configuration, a
3777 simple memory test is run that determines the size of the SDRAM
3780 When there is more than one SDRAM bank, and the banks are of
3781 different size, the largest is mapped first. For equal size, the first
3782 bank (CS2#) is mapped first. The first mapping is always for address
3783 0x00000000, with any additional banks following immediately to create
3784 contiguous memory starting from 0.
3786 Then, the monitor installs itself at the upper end of the SDRAM area
3787 and allocates memory for use by malloc() and for the global Board
3788 Info data; also, the exception vector code is copied to the low RAM
3789 pages, and the final stack is set up.
3791 Only after this relocation will you have a "normal" C environment;
3792 until that you are restricted in several ways, mostly because you are
3793 running from ROM, and because the code will have to be relocated to a
3797 U-Boot Porting Guide:
3798 ----------------------
3800 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3804 int main (int argc, char *argv[])
3806 sighandler_t no_more_time;
3808 signal (SIGALRM, no_more_time);
3809 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3811 if (available_money > available_manpower) {
3812 pay consultant to port U-Boot;
3816 Download latest U-Boot source;
3818 Subscribe to u-boot-users mailing list;
3821 email ("Hi, I am new to U-Boot, how do I get started?");
3825 Read the README file in the top level directory;
3826 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3827 Read the source, Luke;
3830 if (available_money > toLocalCurrency ($2500)) {
3833 Add a lot of aggravation and time;
3836 Create your own board support subdirectory;
3838 Create your own board config file;
3842 Add / modify source code;
3846 email ("Hi, I am having problems...");
3848 Send patch file to Wolfgang;
3853 void no_more_time (int sig)
3862 All contributions to U-Boot should conform to the Linux kernel
3863 coding style; see the file "Documentation/CodingStyle" and the script
3864 "scripts/Lindent" in your Linux kernel source directory. In sources
3865 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3866 spaces before parameters to function calls) is actually used.
3868 Source files originating from a different project (for example the
3869 MTD subsystem) are generally exempt from these guidelines and are not
3870 reformated to ease subsequent migration to newer versions of those
3873 Please note that U-Boot is implemented in C (and to some small parts in
3874 Assembler); no C++ is used, so please do not use C++ style comments (//)
3877 Please also stick to the following formatting rules:
3878 - remove any trailing white space
3879 - use TAB characters for indentation, not spaces
3880 - make sure NOT to use DOS '\r\n' line feeds
3881 - do not add more than 2 empty lines to source files
3882 - do not add trailing empty lines to source files
3884 Submissions which do not conform to the standards may be returned
3885 with a request to reformat the changes.
3891 Since the number of patches for U-Boot is growing, we need to
3892 establish some rules. Submissions which do not conform to these rules
3893 may be rejected, even when they contain important and valuable stuff.
3895 Patches shall be sent to the u-boot-users mailing list.
3897 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3899 When you send a patch, please include the following information with
3902 * For bug fixes: a description of the bug and how your patch fixes
3903 this bug. Please try to include a way of demonstrating that the
3904 patch actually fixes something.
3906 * For new features: a description of the feature and your
3909 * A CHANGELOG entry as plaintext (separate from the patch)
3911 * For major contributions, your entry to the CREDITS file
3913 * When you add support for a new board, don't forget to add this
3914 board to the MAKEALL script, too.
3916 * If your patch adds new configuration options, don't forget to
3917 document these in the README file.
3919 * The patch itself. If you are using git (which is *strongly*
3920 recommended) you can easily generate the patch using the
3921 "git-format-patch". If you then use "git-send-email" to send it to
3922 the U-Boot mailing list, you will avoid most of the common problems
3923 with some other mail clients.
3925 If you cannot use git, use "diff -purN OLD NEW". If your version of
3926 diff does not support these options, then get the latest version of
3929 The current directory when running this command shall be the parent
3930 directory of the U-Boot source tree (i. e. please make sure that
3931 your patch includes sufficient directory information for the
3934 We prefer patches as plain text. MIME attachments are discouraged,
3935 and compressed attachments must not be used.
3937 * If one logical set of modifications affects or creates several
3938 files, all these changes shall be submitted in a SINGLE patch file.
3940 * Changesets that contain different, unrelated modifications shall be
3941 submitted as SEPARATE patches, one patch per changeset.
3946 * Before sending the patch, run the MAKEALL script on your patched
3947 source tree and make sure that no errors or warnings are reported
3948 for any of the boards.
3950 * Keep your modifications to the necessary minimum: A patch
3951 containing several unrelated changes or arbitrary reformats will be
3952 returned with a request to re-formatting / split it.
3954 * If you modify existing code, make sure that your new code does not
3955 add to the memory footprint of the code ;-) Small is beautiful!
3956 When adding new features, these should compile conditionally only
3957 (using #ifdef), and the resulting code with the new feature
3958 disabled must not need more memory than the old code without your
3961 * Remember that there is a size limit of 40 kB per message on the
3962 u-boot-users mailing list. Bigger patches will be moderated. If
3963 they are reasonable and not bigger than 100 kB, they will be
3964 acknowledged. Even bigger patches should be avoided.
projects / platform / kernel / u-boot.git / blob