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-build (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 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
157 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
158 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
159 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
160 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
161 - mips Files specific to MIPS CPUs
162 - mpc5xx Files specific to Freescale MPC5xx CPUs
163 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
164 - mpc8xx Files specific to Freescale MPC8xx CPUs
165 - mpc8220 Files specific to Freescale MPC8220 CPUs
166 - mpc824x Files specific to Freescale MPC824x CPUs
167 - mpc8260 Files specific to Freescale MPC8260 CPUs
168 - mpc85xx Files specific to Freescale MPC85xx CPUs
169 - nios Files specific to Altera NIOS CPUs
170 - nios2 Files specific to Altera Nios-II CPUs
171 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
172 - pxa Files specific to Intel XScale PXA CPUs
173 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
174 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
175 - disk Code for disk drive partition handling
176 - doc Documentation (don't expect too much)
177 - drivers Commonly used device drivers
178 - dtt Digital Thermometer and Thermostat drivers
179 - examples Example code for standalone applications, etc.
180 - include Header Files
181 - lib_arm Files generic to ARM architecture
182 - lib_avr32 Files generic to AVR32 architecture
183 - lib_generic Files generic to all architectures
184 - lib_i386 Files generic to i386 architecture
185 - lib_m68k Files generic to m68k architecture
186 - lib_mips Files generic to MIPS architecture
187 - lib_nios Files generic to NIOS architecture
188 - lib_ppc Files generic to PowerPC architecture
189 - libfdt Library files to support flattened device trees
190 - net Networking code
191 - post Power On Self Test
192 - rtc Real Time Clock drivers
193 - tools Tools to build S-Record or U-Boot images, etc.
195 Software Configuration:
196 =======================
198 Configuration is usually done using C preprocessor defines; the
199 rationale behind that is to avoid dead code whenever possible.
201 There are two classes of configuration variables:
203 * Configuration _OPTIONS_:
204 These are selectable by the user and have names beginning with
207 * Configuration _SETTINGS_:
208 These depend on the hardware etc. and should not be meddled with if
209 you don't know what you're doing; they have names beginning with
212 Later we will add a configuration tool - probably similar to or even
213 identical to what's used for the Linux kernel. Right now, we have to
214 do the configuration by hand, which means creating some symbolic
215 links and editing some configuration files. We use the TQM8xxL boards
219 Selection of Processor Architecture and Board Type:
220 ---------------------------------------------------
222 For all supported boards there are ready-to-use default
223 configurations available; just type "make <board_name>_config".
225 Example: For a TQM823L module type:
230 For the Cogent platform, you need to specify the cpu type as well;
231 e.g. "make cogent_mpc8xx_config". And also configure the cogent
232 directory according to the instructions in cogent/README.
235 Configuration Options:
236 ----------------------
238 Configuration depends on the combination of board and CPU type; all
239 such information is kept in a configuration file
240 "include/configs/<board_name>.h".
242 Example: For a TQM823L module, all configuration settings are in
243 "include/configs/TQM823L.h".
246 Many of the options are named exactly as the corresponding Linux
247 kernel configuration options. The intention is to make it easier to
248 build a config tool - later.
251 The following options need to be configured:
253 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
255 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
257 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
258 Define exactly one, e.g. CONFIG_ATSTK1002
260 - CPU Module Type: (if CONFIG_COGENT is defined)
261 Define exactly one of
263 --- FIXME --- not tested yet:
264 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
265 CONFIG_CMA287_23, CONFIG_CMA287_50
267 - Motherboard Type: (if CONFIG_COGENT is defined)
268 Define exactly one of
269 CONFIG_CMA101, CONFIG_CMA102
271 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
272 Define one or more of
275 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
276 Define one or more of
277 CONFIG_LCD_HEARTBEAT - update a character position on
278 the lcd display every second with
281 - Board flavour: (if CONFIG_MPC8260ADS is defined)
284 CFG_8260ADS - original MPC8260ADS
285 CFG_8266ADS - MPC8266ADS
286 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
287 CFG_8272ADS - MPC8272ADS
289 - MPC824X Family Member (if CONFIG_MPC824X is defined)
290 Define exactly one of
291 CONFIG_MPC8240, CONFIG_MPC8245
293 - 8xx CPU Options: (if using an MPC8xx cpu)
294 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
295 get_gclk_freq() cannot work
296 e.g. if there is no 32KHz
297 reference PIT/RTC clock
298 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
301 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
304 CONFIG_8xx_CPUCLK_DEFAULT
305 See doc/README.MPC866
309 Define this to measure the actual CPU clock instead
310 of relying on the correctness of the configured
311 values. Mostly useful for board bringup to make sure
312 the PLL is locked at the intended frequency. Note
313 that this requires a (stable) reference clock (32 kHz
314 RTC clock or CFG_8XX_XIN)
316 - Intel Monahans options:
317 CFG_MONAHANS_RUN_MODE_OSC_RATIO
319 Defines the Monahans run mode to oscillator
320 ratio. Valid values are 8, 16, 24, 31. The core
321 frequency is this value multiplied by 13 MHz.
323 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
325 Defines the Monahans turbo mode to oscillator
326 ratio. Valid values are 1 (default if undefined) and
327 2. The core frequency as calculated above is multiplied
330 - Linux Kernel Interface:
333 U-Boot stores all clock information in Hz
334 internally. For binary compatibility with older Linux
335 kernels (which expect the clocks passed in the
336 bd_info data to be in MHz) the environment variable
337 "clocks_in_mhz" can be defined so that U-Boot
338 converts clock data to MHZ before passing it to the
340 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
341 "clocks_in_mhz=1" is automatically included in the
344 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
346 When transfering memsize parameter to linux, some versions
347 expect it to be in bytes, others in MB.
348 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
350 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
352 New kernel versions are expecting firmware settings to be
353 passed using flattened device trees (based on open firmware
357 * New libfdt-based support
358 * Adds the "fdt" command
359 * The bootm command automatically updates the fdt
362 * Deprecated, see CONFIG_OF_LIBFDT
363 * Original ft_build.c-based support
364 * Automatically modifies the dft as part of the bootm command
365 * The environment variable "disable_of", when set,
366 disables this functionality.
368 OF_CPU - The proper name of the cpus node.
369 OF_SOC - The proper name of the soc node.
370 OF_TBCLK - The timebase frequency.
371 OF_STDOUT_PATH - The path to the console device
373 boards with QUICC Engines require OF_QE to set UCC mac addresses
377 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
378 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
379 will have a copy of the bd_t. Space should be
380 pre-allocated in the dts for the bd_t.
382 CONFIG_OF_HAS_UBOOT_ENV
384 * CONFIG_OF_LIBFDT - enables the "fdt env" command
385 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
386 will have a copy of u-boot's environment variables
388 CONFIG_OF_BOARD_SETUP
390 Board code has addition modification that it wants to make
391 to the flat device tree before handing it off to the kernel
395 This define fills in the correct boot cpu in the boot
396 param header, the default value is zero if undefined.
401 Define this if you want support for Amba PrimeCell PL010 UARTs.
405 Define this if you want support for Amba PrimeCell PL011 UARTs.
409 If you have Amba PrimeCell PL011 UARTs, set this variable to
410 the clock speed of the UARTs.
414 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
415 define this to a list of base addresses for each (supported)
416 port. See e.g. include/configs/versatile.h
420 Depending on board, define exactly one serial port
421 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
422 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
423 console by defining CONFIG_8xx_CONS_NONE
425 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
426 port routines must be defined elsewhere
427 (i.e. serial_init(), serial_getc(), ...)
430 Enables console device for a color framebuffer. Needs following
431 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
432 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
434 VIDEO_HW_RECTFILL graphic chip supports
437 VIDEO_HW_BITBLT graphic chip supports
438 bit-blit (cf. smiLynxEM)
439 VIDEO_VISIBLE_COLS visible pixel columns
441 VIDEO_VISIBLE_ROWS visible pixel rows
442 VIDEO_PIXEL_SIZE bytes per pixel
443 VIDEO_DATA_FORMAT graphic data format
444 (0-5, cf. cfb_console.c)
445 VIDEO_FB_ADRS framebuffer address
446 VIDEO_KBD_INIT_FCT keyboard int fct
447 (i.e. i8042_kbd_init())
448 VIDEO_TSTC_FCT test char fct
450 VIDEO_GETC_FCT get char fct
452 CONFIG_CONSOLE_CURSOR cursor drawing on/off
453 (requires blink timer
455 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
456 CONFIG_CONSOLE_TIME display time/date info in
458 (requires CONFIG_CMD_DATE)
459 CONFIG_VIDEO_LOGO display Linux logo in
461 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
462 linux_logo.h for logo.
463 Requires CONFIG_VIDEO_LOGO
464 CONFIG_CONSOLE_EXTRA_INFO
465 addional board info beside
468 When CONFIG_CFB_CONSOLE is defined, video console is
469 default i/o. Serial console can be forced with
470 environment 'console=serial'.
472 When CONFIG_SILENT_CONSOLE is defined, all console
473 messages (by U-Boot and Linux!) can be silenced with
474 the "silent" environment variable. See
475 doc/README.silent for more information.
478 CONFIG_BAUDRATE - in bps
479 Select one of the baudrates listed in
480 CFG_BAUDRATE_TABLE, see below.
481 CFG_BRGCLK_PRESCALE, baudrate prescale
483 - Interrupt driven serial port input:
484 CONFIG_SERIAL_SOFTWARE_FIFO
487 Use an interrupt handler for receiving data on the
488 serial port. It also enables using hardware handshake
489 (RTS/CTS) and UART's built-in FIFO. Set the number of
490 bytes the interrupt driven input buffer should have.
492 Leave undefined to disable this feature, including
493 disable the buffer and hardware handshake.
495 - Console UART Number:
499 If defined internal UART1 (and not UART0) is used
500 as default U-Boot console.
502 - Boot Delay: CONFIG_BOOTDELAY - in seconds
503 Delay before automatically booting the default image;
504 set to -1 to disable autoboot.
506 See doc/README.autoboot for these options that
507 work with CONFIG_BOOTDELAY. None are required.
508 CONFIG_BOOT_RETRY_TIME
509 CONFIG_BOOT_RETRY_MIN
510 CONFIG_AUTOBOOT_KEYED
511 CONFIG_AUTOBOOT_PROMPT
512 CONFIG_AUTOBOOT_DELAY_STR
513 CONFIG_AUTOBOOT_STOP_STR
514 CONFIG_AUTOBOOT_DELAY_STR2
515 CONFIG_AUTOBOOT_STOP_STR2
516 CONFIG_ZERO_BOOTDELAY_CHECK
517 CONFIG_RESET_TO_RETRY
521 Only needed when CONFIG_BOOTDELAY is enabled;
522 define a command string that is automatically executed
523 when no character is read on the console interface
524 within "Boot Delay" after reset.
527 This can be used to pass arguments to the bootm
528 command. The value of CONFIG_BOOTARGS goes into the
529 environment value "bootargs".
531 CONFIG_RAMBOOT and CONFIG_NFSBOOT
532 The value of these goes into the environment as
533 "ramboot" and "nfsboot" respectively, and can be used
534 as a convenience, when switching between booting from
540 When this option is #defined, the existence of the
541 environment variable "preboot" will be checked
542 immediately before starting the CONFIG_BOOTDELAY
543 countdown and/or running the auto-boot command resp.
544 entering interactive mode.
546 This feature is especially useful when "preboot" is
547 automatically generated or modified. For an example
548 see the LWMON board specific code: here "preboot" is
549 modified when the user holds down a certain
550 combination of keys on the (special) keyboard when
553 - Serial Download Echo Mode:
555 If defined to 1, all characters received during a
556 serial download (using the "loads" command) are
557 echoed back. This might be needed by some terminal
558 emulations (like "cu"), but may as well just take
559 time on others. This setting #define's the initial
560 value of the "loads_echo" environment variable.
562 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
564 Select one of the baudrates listed in
565 CFG_BAUDRATE_TABLE, see below.
568 Monitor commands can be included or excluded
569 from the build by using the #include files
570 "config_cmd_all.h" and #undef'ing unwanted
571 commands, or using "config_cmd_default.h"
572 and augmenting with additional #define's
575 The default command configuration includes all commands
576 except those marked below with a "*".
578 CONFIG_CMD_ASKENV * ask for env variable
579 CONFIG_CMD_AUTOSCRIPT Autoscript Support
580 CONFIG_CMD_BDI bdinfo
581 CONFIG_CMD_BEDBUG * Include BedBug Debugger
582 CONFIG_CMD_BMP * BMP support
583 CONFIG_CMD_BSP * Board specific commands
584 CONFIG_CMD_BOOTD bootd
585 CONFIG_CMD_CACHE * icache, dcache
586 CONFIG_CMD_CONSOLE coninfo
587 CONFIG_CMD_DATE * support for RTC, date/time...
588 CONFIG_CMD_DHCP * DHCP support
589 CONFIG_CMD_DIAG * Diagnostics
590 CONFIG_CMD_DOC * Disk-On-Chip Support
591 CONFIG_CMD_DTT * Digital Therm and Thermostat
592 CONFIG_CMD_ECHO echo arguments
593 CONFIG_CMD_EEPROM * EEPROM read/write support
594 CONFIG_CMD_ELF * bootelf, bootvx
595 CONFIG_CMD_ENV saveenv
596 CONFIG_CMD_FDC * Floppy Disk Support
597 CONFIG_CMD_FAT * FAT partition support
598 CONFIG_CMD_FDOS * Dos diskette Support
599 CONFIG_CMD_FLASH flinfo, erase, protect
600 CONFIG_CMD_FPGA FPGA device initialization support
601 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
602 CONFIG_CMD_I2C * I2C serial bus support
603 CONFIG_CMD_IDE * IDE harddisk support
604 CONFIG_CMD_IMI iminfo
605 CONFIG_CMD_IMLS List all found images
606 CONFIG_CMD_IMMAP * IMMR dump support
607 CONFIG_CMD_IRQ * irqinfo
608 CONFIG_CMD_ITEST Integer/string test of 2 values
609 CONFIG_CMD_JFFS2 * JFFS2 Support
610 CONFIG_CMD_KGDB * kgdb
611 CONFIG_CMD_LOADB loadb
612 CONFIG_CMD_LOADS loads
613 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
615 CONFIG_CMD_MISC Misc functions like sleep etc
616 CONFIG_CMD_MMC * MMC memory mapped support
617 CONFIG_CMD_MII * MII utility commands
618 CONFIG_CMD_NAND * NAND support
619 CONFIG_CMD_NET bootp, tftpboot, rarpboot
620 CONFIG_CMD_PCI * pciinfo
621 CONFIG_CMD_PCMCIA * PCMCIA support
622 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
624 CONFIG_CMD_PORTIO * Port I/O
625 CONFIG_CMD_REGINFO * Register dump
626 CONFIG_CMD_RUN run command in env variable
627 CONFIG_CMD_SAVES * save S record dump
628 CONFIG_CMD_SCSI * SCSI Support
629 CONFIG_CMD_SDRAM * print SDRAM configuration information
630 (requires CONFIG_CMD_I2C)
631 CONFIG_CMD_SETGETDCR Support for DCR Register access
633 CONFIG_CMD_SPI * SPI serial bus support
634 CONFIG_CMD_USB * USB support
635 CONFIG_CMD_VFD * VFD support (TRAB)
636 CONFIG_CMD_BSP * Board SPecific functions
637 CONFIG_CMD_CDP * Cisco Discover Protocol support
638 CONFIG_CMD_FSL * Microblaze FSL support
641 EXAMPLE: If you want all functions except of network
642 support you can write:
644 #include "config_cmd_all.h"
645 #undef CONFIG_CMD_NET
648 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
650 Note: Don't enable the "icache" and "dcache" commands
651 (configuration option CONFIG_CMD_CACHE) unless you know
652 what you (and your U-Boot users) are doing. Data
653 cache cannot be enabled on systems like the 8xx or
654 8260 (where accesses to the IMMR region must be
655 uncached), and it cannot be disabled on all other
656 systems where we (mis-) use the data cache to hold an
657 initial stack and some data.
660 XXX - this list needs to get updated!
664 If this variable is defined, it enables watchdog
665 support. There must be support in the platform specific
666 code for a watchdog. For the 8xx and 8260 CPUs, the
667 SIU Watchdog feature is enabled in the SYPCR
671 CONFIG_VERSION_VARIABLE
672 If this variable is defined, an environment variable
673 named "ver" is created by U-Boot showing the U-Boot
674 version as printed by the "version" command.
675 This variable is readonly.
679 When CONFIG_CMD_DATE is selected, the type of the RTC
680 has to be selected, too. Define exactly one of the
683 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
684 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
685 CONFIG_RTC_MC146818 - use MC146818 RTC
686 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
687 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
688 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
689 CONFIG_RTC_DS164x - use Dallas DS164x RTC
690 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
691 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
693 Note that if the RTC uses I2C, then the I2C interface
694 must also be configured. See I2C Support, below.
698 When CONFIG_TIMESTAMP is selected, the timestamp
699 (date and time) of an image is printed by image
700 commands like bootm or iminfo. This option is
701 automatically enabled when you select CONFIG_CMD_DATE .
704 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
705 and/or CONFIG_ISO_PARTITION
707 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
708 CONFIG_CMD_SCSI) you must configure support for at
709 least one partition type as well.
712 CONFIG_IDE_RESET_ROUTINE - this is defined in several
713 board configurations files but used nowhere!
715 CONFIG_IDE_RESET - is this is defined, IDE Reset will
716 be performed by calling the function
717 ide_set_reset(int reset)
718 which has to be defined in a board specific file
723 Set this to enable ATAPI support.
728 Set this to enable support for disks larger than 137GB
729 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
730 Whithout these , LBA48 support uses 32bit variables and will 'only'
731 support disks up to 2.1TB.
734 When enabled, makes the IDE subsystem use 64bit sector addresses.
738 At the moment only there is only support for the
739 SYM53C8XX SCSI controller; define
740 CONFIG_SCSI_SYM53C8XX to enable it.
742 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
743 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
744 CFG_SCSI_MAX_LUN] can be adjusted to define the
745 maximum numbers of LUNs, SCSI ID's and target
747 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
749 - NETWORK Support (PCI):
751 Support for Intel 8254x gigabit chips.
754 Support for Intel 82557/82559/82559ER chips.
755 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
756 write routine for first time initialisation.
759 Support for Digital 2114x chips.
760 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
761 modem chip initialisation (KS8761/QS6611).
764 Support for National dp83815 chips.
767 Support for National dp8382[01] gigabit chips.
769 - NETWORK Support (other):
771 CONFIG_DRIVER_LAN91C96
772 Support for SMSC's LAN91C96 chips.
775 Define this to hold the physical address
776 of the LAN91C96's I/O space
778 CONFIG_LAN91C96_USE_32_BIT
779 Define this to enable 32 bit addressing
781 CONFIG_DRIVER_SMC91111
782 Support for SMSC's LAN91C111 chip
785 Define this to hold the physical address
786 of the device (I/O space)
788 CONFIG_SMC_USE_32_BIT
789 Define this if data bus is 32 bits
791 CONFIG_SMC_USE_IOFUNCS
792 Define this to use i/o functions instead of macros
793 (some hardware wont work with macros)
796 At the moment only the UHCI host controller is
797 supported (PIP405, MIP405, MPC5200); define
798 CONFIG_USB_UHCI to enable it.
799 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
800 and define CONFIG_USB_STORAGE to enable the USB
803 Supported are USB Keyboards and USB Floppy drives
805 MPC5200 USB requires additional defines:
807 for 528 MHz Clock: 0x0001bbbb
809 for differential drivers: 0x00001000
810 for single ended drivers: 0x00005000
812 May be defined to allow interrupt polling
813 instead of using asynchronous interrupts
816 Define the below if you wish to use the USB console.
817 Once firmware is rebuilt from a serial console issue the
818 command "setenv stdin usbtty; setenv stdout usbtty" and
819 attach your usb cable. The Unix command "dmesg" should print
820 it has found a new device. The environment variable usbtty
821 can be set to gserial or cdc_acm to enable your device to
822 appear to a USB host as a Linux gserial device or a
823 Common Device Class Abstract Control Model serial device.
824 If you select usbtty = gserial you should be able to enumerate
826 # modprobe usbserial vendor=0xVendorID product=0xProductID
827 else if using cdc_acm, simply setting the environment
828 variable usbtty to be cdc_acm should suffice. The following
829 might be defined in YourBoardName.h
832 Define this to build a UDC device
835 Define this to have a tty type of device available to
836 talk to the UDC device
838 CFG_CONSOLE_IS_IN_ENV
839 Define this if you want stdin, stdout &/or stderr to
843 CFG_USB_EXTC_CLK 0xBLAH
844 Derive USB clock from external clock "blah"
845 - CFG_USB_EXTC_CLK 0x02
847 CFG_USB_BRG_CLK 0xBLAH
848 Derive USB clock from brgclk
849 - CFG_USB_BRG_CLK 0x04
851 If you have a USB-IF assigned VendorID then you may wish to
852 define your own vendor specific values either in BoardName.h
853 or directly in usbd_vendor_info.h. If you don't define
854 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
855 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
856 should pretend to be a Linux device to it's target host.
858 CONFIG_USBD_MANUFACTURER
859 Define this string as the name of your company for
860 - CONFIG_USBD_MANUFACTURER "my company"
862 CONFIG_USBD_PRODUCT_NAME
863 Define this string as the name of your product
864 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
867 Define this as your assigned Vendor ID from the USB
868 Implementors Forum. This *must* be a genuine Vendor ID
869 to avoid polluting the USB namespace.
870 - CONFIG_USBD_VENDORID 0xFFFF
872 CONFIG_USBD_PRODUCTID
873 Define this as the unique Product ID
875 - CONFIG_USBD_PRODUCTID 0xFFFF
879 The MMC controller on the Intel PXA is supported. To
880 enable this define CONFIG_MMC. The MMC can be
881 accessed from the boot prompt by mapping the device
882 to physical memory similar to flash. Command line is
883 enabled with CONFIG_CMD_MMC. The MMC driver also works with
884 the FAT fs. This is enabled with CONFIG_CMD_FAT.
886 - Journaling Flash filesystem support:
887 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
888 CONFIG_JFFS2_NAND_DEV
889 Define these for a default partition on a NAND device
891 CFG_JFFS2_FIRST_SECTOR,
892 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
893 Define these for a default partition on a NOR device
896 Define this to create an own partition. You have to provide a
897 function struct part_info* jffs2_part_info(int part_num)
899 If you define only one JFFS2 partition you may also want to
900 #define CFG_JFFS_SINGLE_PART 1
901 to disable the command chpart. This is the default when you
902 have not defined a custom partition
907 Define this to enable standard (PC-Style) keyboard
911 Standard PC keyboard driver with US (is default) and
912 GERMAN key layout (switch via environment 'keymap=de') support.
913 Export function i8042_kbd_init, i8042_tstc and i8042_getc
914 for cfb_console. Supports cursor blinking.
919 Define this to enable video support (for output to
924 Enable Chips & Technologies 69000 Video chip
926 CONFIG_VIDEO_SMI_LYNXEM
927 Enable Silicon Motion SMI 712/710/810 Video chip. The
928 video output is selected via environment 'videoout'
929 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
932 For the CT69000 and SMI_LYNXEM drivers, videomode is
933 selected via environment 'videomode'. Two diferent ways
935 - "videomode=num" 'num' is a standard LiLo mode numbers.
936 Following standard modes are supported (* is default):
938 Colors 640x480 800x600 1024x768 1152x864 1280x1024
939 -------------+---------------------------------------------
940 8 bits | 0x301* 0x303 0x305 0x161 0x307
941 15 bits | 0x310 0x313 0x316 0x162 0x319
942 16 bits | 0x311 0x314 0x317 0x163 0x31A
943 24 bits | 0x312 0x315 0x318 ? 0x31B
944 -------------+---------------------------------------------
945 (i.e. setenv videomode 317; saveenv; reset;)
947 - "videomode=bootargs" all the video parameters are parsed
948 from the bootargs. (See drivers/video/videomodes.c)
951 CONFIG_VIDEO_SED13806
952 Enable Epson SED13806 driver. This driver supports 8bpp
953 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
954 or CONFIG_VIDEO_SED13806_16BPP
959 Define this to enable a custom keyboard support.
960 This simply calls drv_keyboard_init() which must be
961 defined in your board-specific files.
962 The only board using this so far is RBC823.
964 - LCD Support: CONFIG_LCD
966 Define this to enable LCD support (for output to LCD
967 display); also select one of the supported displays
968 by defining one of these:
970 CONFIG_NEC_NL6448AC33:
972 NEC NL6448AC33-18. Active, color, single scan.
974 CONFIG_NEC_NL6448BC20
976 NEC NL6448BC20-08. 6.5", 640x480.
977 Active, color, single scan.
979 CONFIG_NEC_NL6448BC33_54
981 NEC NL6448BC33-54. 10.4", 640x480.
982 Active, color, single scan.
986 Sharp 320x240. Active, color, single scan.
987 It isn't 16x9, and I am not sure what it is.
989 CONFIG_SHARP_LQ64D341
991 Sharp LQ64D341 display, 640x480.
992 Active, color, single scan.
996 HLD1045 display, 640x480.
997 Active, color, single scan.
1001 Optrex CBL50840-2 NF-FW 99 22 M5
1003 Hitachi LMG6912RPFC-00T
1007 320x240. Black & white.
1009 Normally display is black on white background; define
1010 CFG_WHITE_ON_BLACK to get it inverted.
1012 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1014 If this option is set, the environment is checked for
1015 a variable "splashimage". If found, the usual display
1016 of logo, copyright and system information on the LCD
1017 is suppressed and the BMP image at the address
1018 specified in "splashimage" is loaded instead. The
1019 console is redirected to the "nulldev", too. This
1020 allows for a "silent" boot where a splash screen is
1021 loaded very quickly after power-on.
1023 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1025 If this option is set, additionally to standard BMP
1026 images, gzipped BMP images can be displayed via the
1027 splashscreen support or the bmp command.
1029 - Compression support:
1032 If this option is set, support for bzip2 compressed
1033 images is included. If not, only uncompressed and gzip
1034 compressed images are supported.
1036 NOTE: the bzip2 algorithm requires a lot of RAM, so
1037 the malloc area (as defined by CFG_MALLOC_LEN) should
1043 The address of PHY on MII bus.
1045 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1047 The clock frequency of the MII bus
1051 If this option is set, support for speed/duplex
1052 detection of Gigabit PHY is included.
1054 CONFIG_PHY_RESET_DELAY
1056 Some PHY like Intel LXT971A need extra delay after
1057 reset before any MII register access is possible.
1058 For such PHY, set this option to the usec delay
1059 required. (minimum 300usec for LXT971A)
1061 CONFIG_PHY_CMD_DELAY (ppc4xx)
1063 Some PHY like Intel LXT971A need extra delay after
1064 command issued before MII status register can be read
1071 Define a default value for ethernet address to use
1072 for the respective ethernet interface, in case this
1073 is not determined automatically.
1078 Define a default value for the IP address to use for
1079 the default ethernet interface, in case this is not
1080 determined through e.g. bootp.
1082 - Server IP address:
1085 Defines a default value for theIP address of a TFTP
1086 server to contact when using the "tftboot" command.
1088 - Multicast TFTP Mode:
1091 Defines whether you want to support multicast TFTP as per
1092 rfc-2090; for example to work with atftp. Lets lots of targets
1093 tftp down the same boot image concurrently. Note: the ethernet
1094 driver in use must provide a function: mcast() to join/leave a
1097 CONFIG_BOOTP_RANDOM_DELAY
1098 - BOOTP Recovery Mode:
1099 CONFIG_BOOTP_RANDOM_DELAY
1101 If you have many targets in a network that try to
1102 boot using BOOTP, you may want to avoid that all
1103 systems send out BOOTP requests at precisely the same
1104 moment (which would happen for instance at recovery
1105 from a power failure, when all systems will try to
1106 boot, thus flooding the BOOTP server. Defining
1107 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1108 inserted before sending out BOOTP requests. The
1109 following delays are inserted then:
1111 1st BOOTP request: delay 0 ... 1 sec
1112 2nd BOOTP request: delay 0 ... 2 sec
1113 3rd BOOTP request: delay 0 ... 4 sec
1115 BOOTP requests: delay 0 ... 8 sec
1117 - DHCP Advanced Options:
1118 You can fine tune the DHCP functionality by defining
1119 CONFIG_BOOTP_* symbols:
1121 CONFIG_BOOTP_SUBNETMASK
1122 CONFIG_BOOTP_GATEWAY
1123 CONFIG_BOOTP_HOSTNAME
1124 CONFIG_BOOTP_NISDOMAIN
1125 CONFIG_BOOTP_BOOTPATH
1126 CONFIG_BOOTP_BOOTFILESIZE
1129 CONFIG_BOOTP_SEND_HOSTNAME
1130 CONFIG_BOOTP_NTPSERVER
1131 CONFIG_BOOTP_TIMEOFFSET
1132 CONFIG_BOOTP_VENDOREX
1134 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1135 environment variable, not the BOOTP server.
1137 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1138 serverip from a DHCP server, it is possible that more
1139 than one DNS serverip is offered to the client.
1140 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1141 serverip will be stored in the additional environment
1142 variable "dnsip2". The first DNS serverip is always
1143 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1146 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1147 to do a dynamic update of a DNS server. To do this, they
1148 need the hostname of the DHCP requester.
1149 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1150 of the "hostname" environment variable is passed as
1151 option 12 to the DHCP server.
1154 CONFIG_CDP_DEVICE_ID
1156 The device id used in CDP trigger frames.
1158 CONFIG_CDP_DEVICE_ID_PREFIX
1160 A two character string which is prefixed to the MAC address
1165 A printf format string which contains the ascii name of
1166 the port. Normally is set to "eth%d" which sets
1167 eth0 for the first ethernet, eth1 for the second etc.
1169 CONFIG_CDP_CAPABILITIES
1171 A 32bit integer which indicates the device capabilities;
1172 0x00000010 for a normal host which does not forwards.
1176 An ascii string containing the version of the software.
1180 An ascii string containing the name of the platform.
1184 A 32bit integer sent on the trigger.
1186 CONFIG_CDP_POWER_CONSUMPTION
1188 A 16bit integer containing the power consumption of the
1189 device in .1 of milliwatts.
1191 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1193 A byte containing the id of the VLAN.
1195 - Status LED: CONFIG_STATUS_LED
1197 Several configurations allow to display the current
1198 status using a LED. For instance, the LED will blink
1199 fast while running U-Boot code, stop blinking as
1200 soon as a reply to a BOOTP request was received, and
1201 start blinking slow once the Linux kernel is running
1202 (supported by a status LED driver in the Linux
1203 kernel). Defining CONFIG_STATUS_LED enables this
1206 - CAN Support: CONFIG_CAN_DRIVER
1208 Defining CONFIG_CAN_DRIVER enables CAN driver support
1209 on those systems that support this (optional)
1210 feature, like the TQM8xxL modules.
1212 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1214 These enable I2C serial bus commands. Defining either of
1215 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1216 include the appropriate I2C driver for the selected cpu.
1218 This will allow you to use i2c commands at the u-boot
1219 command line (as long as you set CONFIG_CMD_I2C in
1220 CONFIG_COMMANDS) and communicate with i2c based realtime
1221 clock chips. See common/cmd_i2c.c for a description of the
1222 command line interface.
1224 CONFIG_I2C_CMD_TREE is a recommended option that places
1225 all I2C commands under a single 'i2c' root command. The
1226 older 'imm', 'imd', 'iprobe' etc. commands are considered
1227 deprecated and may disappear in the future.
1229 CONFIG_HARD_I2C selects a hardware I2C controller.
1231 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1232 bit-banging) driver instead of CPM or similar hardware
1235 There are several other quantities that must also be
1236 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1238 In both cases you will need to define CFG_I2C_SPEED
1239 to be the frequency (in Hz) at which you wish your i2c bus
1240 to run and CFG_I2C_SLAVE to be the address of this node (ie
1241 the cpu's i2c node address).
1243 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1244 sets the cpu up as a master node and so its address should
1245 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1246 p.16-473). So, set CFG_I2C_SLAVE to 0.
1248 That's all that's required for CONFIG_HARD_I2C.
1250 If you use the software i2c interface (CONFIG_SOFT_I2C)
1251 then the following macros need to be defined (examples are
1252 from include/configs/lwmon.h):
1256 (Optional). Any commands necessary to enable the I2C
1257 controller or configure ports.
1259 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1263 (Only for MPC8260 CPU). The I/O port to use (the code
1264 assumes both bits are on the same port). Valid values
1265 are 0..3 for ports A..D.
1269 The code necessary to make the I2C data line active
1270 (driven). If the data line is open collector, this
1273 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1277 The code necessary to make the I2C data line tri-stated
1278 (inactive). If the data line is open collector, this
1281 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1285 Code that returns TRUE if the I2C data line is high,
1288 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1292 If <bit> is TRUE, sets the I2C data line high. If it
1293 is FALSE, it clears it (low).
1295 eg: #define I2C_SDA(bit) \
1296 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1297 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1301 If <bit> is TRUE, sets the I2C clock line high. If it
1302 is FALSE, it clears it (low).
1304 eg: #define I2C_SCL(bit) \
1305 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1306 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1310 This delay is invoked four times per clock cycle so this
1311 controls the rate of data transfer. The data rate thus
1312 is 1 / (I2C_DELAY * 4). Often defined to be something
1315 #define I2C_DELAY udelay(2)
1319 When a board is reset during an i2c bus transfer
1320 chips might think that the current transfer is still
1321 in progress. On some boards it is possible to access
1322 the i2c SCLK line directly, either by using the
1323 processor pin as a GPIO or by having a second pin
1324 connected to the bus. If this option is defined a
1325 custom i2c_init_board() routine in boards/xxx/board.c
1326 is run early in the boot sequence.
1328 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1330 This option enables configuration of bi_iic_fast[] flags
1331 in u-boot bd_info structure based on u-boot environment
1332 variable "i2cfast". (see also i2cfast)
1334 CONFIG_I2C_MULTI_BUS
1336 This option allows the use of multiple I2C buses, each of which
1337 must have a controller. At any point in time, only one bus is
1338 active. To switch to a different bus, use the 'i2c dev' command.
1339 Note that bus numbering is zero-based.
1343 This option specifies a list of I2C devices that will be skipped
1344 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1345 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1346 pairs. Otherwise, specify a 1D array of device addresses
1349 #undef CONFIG_I2C_MULTI_BUS
1350 #define CFG_I2C_NOPROBES {0x50,0x68}
1352 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1354 #define CONFIG_I2C_MULTI_BUS
1355 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1357 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1361 If defined, then this indicates the I2C bus number for DDR SPD.
1362 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1366 If defined, then this indicates the I2C bus number for the RTC.
1367 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1371 If defined, then this indicates the I2C bus number for the DTT.
1372 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1376 Define this option if you want to use Freescale's I2C driver in
1377 drivers/i2c/fsl_i2c.c.
1380 - SPI Support: CONFIG_SPI
1382 Enables SPI driver (so far only tested with
1383 SPI EEPROM, also an instance works with Crystal A/D and
1384 D/As on the SACSng board)
1388 Enables extended (16-bit) SPI EEPROM addressing.
1389 (symmetrical to CONFIG_I2C_X)
1393 Enables a software (bit-bang) SPI driver rather than
1394 using hardware support. This is a general purpose
1395 driver that only requires three general I/O port pins
1396 (two outputs, one input) to function. If this is
1397 defined, the board configuration must define several
1398 SPI configuration items (port pins to use, etc). For
1399 an example, see include/configs/sacsng.h.
1403 Enables a hardware SPI driver for general-purpose reads
1404 and writes. As with CONFIG_SOFT_SPI, the board configuration
1405 must define a list of chip-select function pointers.
1406 Currently supported on some MPC8xxx processors. For an
1407 example, see include/configs/mpc8349emds.h.
1409 - FPGA Support: CONFIG_FPGA
1411 Enables FPGA subsystem.
1413 CONFIG_FPGA_<vendor>
1415 Enables support for specific chip vendors.
1418 CONFIG_FPGA_<family>
1420 Enables support for FPGA family.
1421 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1425 Specify the number of FPGA devices to support.
1427 CFG_FPGA_PROG_FEEDBACK
1429 Enable printing of hash marks during FPGA configuration.
1433 Enable checks on FPGA configuration interface busy
1434 status by the configuration function. This option
1435 will require a board or device specific function to
1440 If defined, a function that provides delays in the FPGA
1441 configuration driver.
1443 CFG_FPGA_CHECK_CTRLC
1444 Allow Control-C to interrupt FPGA configuration
1446 CFG_FPGA_CHECK_ERROR
1448 Check for configuration errors during FPGA bitfile
1449 loading. For example, abort during Virtex II
1450 configuration if the INIT_B line goes low (which
1451 indicated a CRC error).
1455 Maximum time to wait for the INIT_B line to deassert
1456 after PROB_B has been deasserted during a Virtex II
1457 FPGA configuration sequence. The default time is 500
1462 Maximum time to wait for BUSY to deassert during
1463 Virtex II FPGA configuration. The default is 5 mS.
1465 CFG_FPGA_WAIT_CONFIG
1467 Time to wait after FPGA configuration. The default is
1470 - Configuration Management:
1473 If defined, this string will be added to the U-Boot
1474 version information (U_BOOT_VERSION)
1476 - Vendor Parameter Protection:
1478 U-Boot considers the values of the environment
1479 variables "serial#" (Board Serial Number) and
1480 "ethaddr" (Ethernet Address) to be parameters that
1481 are set once by the board vendor / manufacturer, and
1482 protects these variables from casual modification by
1483 the user. Once set, these variables are read-only,
1484 and write or delete attempts are rejected. You can
1485 change this behviour:
1487 If CONFIG_ENV_OVERWRITE is #defined in your config
1488 file, the write protection for vendor parameters is
1489 completely disabled. Anybody can change or delete
1492 Alternatively, if you #define _both_ CONFIG_ETHADDR
1493 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1494 ethernet address is installed in the environment,
1495 which can be changed exactly ONCE by the user. [The
1496 serial# is unaffected by this, i. e. it remains
1502 Define this variable to enable the reservation of
1503 "protected RAM", i. e. RAM which is not overwritten
1504 by U-Boot. Define CONFIG_PRAM to hold the number of
1505 kB you want to reserve for pRAM. You can overwrite
1506 this default value by defining an environment
1507 variable "pram" to the number of kB you want to
1508 reserve. Note that the board info structure will
1509 still show the full amount of RAM. If pRAM is
1510 reserved, a new environment variable "mem" will
1511 automatically be defined to hold the amount of
1512 remaining RAM in a form that can be passed as boot
1513 argument to Linux, for instance like that:
1515 setenv bootargs ... mem=\${mem}
1518 This way you can tell Linux not to use this memory,
1519 either, which results in a memory region that will
1520 not be affected by reboots.
1522 *WARNING* If your board configuration uses automatic
1523 detection of the RAM size, you must make sure that
1524 this memory test is non-destructive. So far, the
1525 following board configurations are known to be
1528 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1529 HERMES, IP860, RPXlite, LWMON, LANTEC,
1530 PCU_E, FLAGADM, TQM8260
1535 Define this variable to stop the system in case of a
1536 fatal error, so that you have to reset it manually.
1537 This is probably NOT a good idea for an embedded
1538 system where you want to system to reboot
1539 automatically as fast as possible, but it may be
1540 useful during development since you can try to debug
1541 the conditions that lead to the situation.
1543 CONFIG_NET_RETRY_COUNT
1545 This variable defines the number of retries for
1546 network operations like ARP, RARP, TFTP, or BOOTP
1547 before giving up the operation. If not defined, a
1548 default value of 5 is used.
1550 - Command Interpreter:
1551 CONFIG_AUTO_COMPLETE
1553 Enable auto completion of commands using TAB.
1555 Note that this feature has NOT been implemented yet
1556 for the "hush" shell.
1561 Define this variable to enable the "hush" shell (from
1562 Busybox) as command line interpreter, thus enabling
1563 powerful command line syntax like
1564 if...then...else...fi conditionals or `&&' and '||'
1565 constructs ("shell scripts").
1567 If undefined, you get the old, much simpler behaviour
1568 with a somewhat smaller memory footprint.
1573 This defines the secondary prompt string, which is
1574 printed when the command interpreter needs more input
1575 to complete a command. Usually "> ".
1579 In the current implementation, the local variables
1580 space and global environment variables space are
1581 separated. Local variables are those you define by
1582 simply typing `name=value'. To access a local
1583 variable later on, you have write `$name' or
1584 `${name}'; to execute the contents of a variable
1585 directly type `$name' at the command prompt.
1587 Global environment variables are those you use
1588 setenv/printenv to work with. To run a command stored
1589 in such a variable, you need to use the run command,
1590 and you must not use the '$' sign to access them.
1592 To store commands and special characters in a
1593 variable, please use double quotation marks
1594 surrounding the whole text of the variable, instead
1595 of the backslashes before semicolons and special
1598 - Commandline Editing and History:
1599 CONFIG_CMDLINE_EDITING
1601 Enable editiong and History functions for interactive
1602 commandline input operations
1604 - Default Environment:
1605 CONFIG_EXTRA_ENV_SETTINGS
1607 Define this to contain any number of null terminated
1608 strings (variable = value pairs) that will be part of
1609 the default environment compiled into the boot image.
1611 For example, place something like this in your
1612 board's config file:
1614 #define CONFIG_EXTRA_ENV_SETTINGS \
1618 Warning: This method is based on knowledge about the
1619 internal format how the environment is stored by the
1620 U-Boot code. This is NOT an official, exported
1621 interface! Although it is unlikely that this format
1622 will change soon, there is no guarantee either.
1623 You better know what you are doing here.
1625 Note: overly (ab)use of the default environment is
1626 discouraged. Make sure to check other ways to preset
1627 the environment like the autoscript function or the
1630 - DataFlash Support:
1631 CONFIG_HAS_DATAFLASH
1633 Defining this option enables DataFlash features and
1634 allows to read/write in Dataflash via the standard
1637 - SystemACE Support:
1640 Adding this option adds support for Xilinx SystemACE
1641 chips attached via some sort of local bus. The address
1642 of the chip must alsh be defined in the
1643 CFG_SYSTEMACE_BASE macro. For example:
1645 #define CONFIG_SYSTEMACE
1646 #define CFG_SYSTEMACE_BASE 0xf0000000
1648 When SystemACE support is added, the "ace" device type
1649 becomes available to the fat commands, i.e. fatls.
1651 - TFTP Fixed UDP Port:
1654 If this is defined, the environment variable tftpsrcp
1655 is used to supply the TFTP UDP source port value.
1656 If tftpsrcp isn't defined, the normal pseudo-random port
1657 number generator is used.
1659 Also, the environment variable tftpdstp is used to supply
1660 the TFTP UDP destination port value. If tftpdstp isn't
1661 defined, the normal port 69 is used.
1663 The purpose for tftpsrcp is to allow a TFTP server to
1664 blindly start the TFTP transfer using the pre-configured
1665 target IP address and UDP port. This has the effect of
1666 "punching through" the (Windows XP) firewall, allowing
1667 the remainder of the TFTP transfer to proceed normally.
1668 A better solution is to properly configure the firewall,
1669 but sometimes that is not allowed.
1671 - Show boot progress:
1672 CONFIG_SHOW_BOOT_PROGRESS
1674 Defining this option allows to add some board-
1675 specific code (calling a user-provided function
1676 "show_boot_progress(int)") that enables you to show
1677 the system's boot progress on some display (for
1678 example, some LED's) on your board. At the moment,
1679 the following checkpoints are implemented:
1682 1 common/cmd_bootm.c before attempting to boot an image
1683 -1 common/cmd_bootm.c Image header has bad magic number
1684 2 common/cmd_bootm.c Image header has correct magic number
1685 -2 common/cmd_bootm.c Image header has bad checksum
1686 3 common/cmd_bootm.c Image header has correct checksum
1687 -3 common/cmd_bootm.c Image data has bad checksum
1688 4 common/cmd_bootm.c Image data has correct checksum
1689 -4 common/cmd_bootm.c Image is for unsupported architecture
1690 5 common/cmd_bootm.c Architecture check OK
1691 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1692 6 common/cmd_bootm.c Image Type check OK
1693 -6 common/cmd_bootm.c gunzip uncompression error
1694 -7 common/cmd_bootm.c Unimplemented compression type
1695 7 common/cmd_bootm.c Uncompression OK
1696 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1697 8 common/cmd_bootm.c Image Type check OK
1698 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1699 9 common/cmd_bootm.c Start initial ramdisk verification
1700 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1701 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1702 10 common/cmd_bootm.c Ramdisk header is OK
1703 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1704 11 common/cmd_bootm.c Ramdisk data has correct checksum
1705 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1706 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1707 13 common/cmd_bootm.c Start multifile image verification
1708 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1709 15 common/cmd_bootm.c All preparation done, transferring control to OS
1711 -30 lib_ppc/board.c Fatal error, hang the system
1712 -31 post/post.c POST test failed, detected by post_output_backlog()
1713 -32 post/post.c POST test failed, detected by post_run_single()
1715 34 common/cmd_doc.c before loading a Image from a DOC device
1716 -35 common/cmd_doc.c Bad usage of "doc" command
1717 35 common/cmd_doc.c correct usage of "doc" command
1718 -36 common/cmd_doc.c No boot device
1719 36 common/cmd_doc.c correct boot device
1720 -37 common/cmd_doc.c Unknown Chip ID on boot device
1721 37 common/cmd_doc.c correct chip ID found, device available
1722 -38 common/cmd_doc.c Read Error on boot device
1723 38 common/cmd_doc.c reading Image header from DOC device OK
1724 -39 common/cmd_doc.c Image header has bad magic number
1725 39 common/cmd_doc.c Image header has correct magic number
1726 -40 common/cmd_doc.c Error reading Image from DOC device
1727 40 common/cmd_doc.c Image header has correct magic number
1728 41 common/cmd_ide.c before loading a Image from a IDE device
1729 -42 common/cmd_ide.c Bad usage of "ide" command
1730 42 common/cmd_ide.c correct usage of "ide" command
1731 -43 common/cmd_ide.c No boot device
1732 43 common/cmd_ide.c boot device found
1733 -44 common/cmd_ide.c Device not available
1734 44 common/cmd_ide.c Device available
1735 -45 common/cmd_ide.c wrong partition selected
1736 45 common/cmd_ide.c partition selected
1737 -46 common/cmd_ide.c Unknown partition table
1738 46 common/cmd_ide.c valid partition table found
1739 -47 common/cmd_ide.c Invalid partition type
1740 47 common/cmd_ide.c correct partition type
1741 -48 common/cmd_ide.c Error reading Image Header on boot device
1742 48 common/cmd_ide.c reading Image Header from IDE device OK
1743 -49 common/cmd_ide.c Image header has bad magic number
1744 49 common/cmd_ide.c Image header has correct magic number
1745 -50 common/cmd_ide.c Image header has bad checksum
1746 50 common/cmd_ide.c Image header has correct checksum
1747 -51 common/cmd_ide.c Error reading Image from IDE device
1748 51 common/cmd_ide.c reading Image from IDE device OK
1749 52 common/cmd_nand.c before loading a Image from a NAND device
1750 -53 common/cmd_nand.c Bad usage of "nand" command
1751 53 common/cmd_nand.c correct usage of "nand" command
1752 -54 common/cmd_nand.c No boot device
1753 54 common/cmd_nand.c boot device found
1754 -55 common/cmd_nand.c Unknown Chip ID on boot device
1755 55 common/cmd_nand.c correct chip ID found, device available
1756 -56 common/cmd_nand.c Error reading Image Header on boot device
1757 56 common/cmd_nand.c reading Image Header from NAND device OK
1758 -57 common/cmd_nand.c Image header has bad magic number
1759 57 common/cmd_nand.c Image header has correct magic number
1760 -58 common/cmd_nand.c Error reading Image from NAND device
1761 58 common/cmd_nand.c reading Image from NAND device OK
1763 -60 common/env_common.c Environment has a bad CRC, using default
1765 64 net/eth.c starting with Ethernetconfiguration.
1766 -64 net/eth.c no Ethernet found.
1767 65 net/eth.c Ethernet found.
1769 -80 common/cmd_net.c usage wrong
1770 80 common/cmd_net.c before calling NetLoop()
1771 -81 common/cmd_net.c some error in NetLoop() occured
1772 81 common/cmd_net.c NetLoop() back without error
1773 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1774 82 common/cmd_net.c trying automatic boot
1775 83 common/cmd_net.c running autoscript
1776 -83 common/cmd_net.c some error in automatic boot or autoscript
1777 84 common/cmd_net.c end without errors
1782 [so far only for SMDK2400 and TRAB boards]
1784 - Modem support endable:
1785 CONFIG_MODEM_SUPPORT
1787 - RTS/CTS Flow control enable:
1790 - Modem debug support:
1791 CONFIG_MODEM_SUPPORT_DEBUG
1793 Enables debugging stuff (char screen[1024], dbg())
1794 for modem support. Useful only with BDI2000.
1796 - Interrupt support (PPC):
1798 There are common interrupt_init() and timer_interrupt()
1799 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1800 for cpu specific initialization. interrupt_init_cpu()
1801 should set decrementer_count to appropriate value. If
1802 cpu resets decrementer automatically after interrupt
1803 (ppc4xx) it should set decrementer_count to zero.
1804 timer_interrupt() calls timer_interrupt_cpu() for cpu
1805 specific handling. If board has watchdog / status_led
1806 / other_activity_monitor it works automatically from
1807 general timer_interrupt().
1811 In the target system modem support is enabled when a
1812 specific key (key combination) is pressed during
1813 power-on. Otherwise U-Boot will boot normally
1814 (autoboot). The key_pressed() fuction is called from
1815 board_init(). Currently key_pressed() is a dummy
1816 function, returning 1 and thus enabling modem
1819 If there are no modem init strings in the
1820 environment, U-Boot proceed to autoboot; the
1821 previous output (banner, info printfs) will be
1824 See also: doc/README.Modem
1827 Configuration Settings:
1828 -----------------------
1830 - CFG_LONGHELP: Defined when you want long help messages included;
1831 undefine this when you're short of memory.
1833 - CFG_PROMPT: This is what U-Boot prints on the console to
1834 prompt for user input.
1836 - CFG_CBSIZE: Buffer size for input from the Console
1838 - CFG_PBSIZE: Buffer size for Console output
1840 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1842 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1843 the application (usually a Linux kernel) when it is
1846 - CFG_BAUDRATE_TABLE:
1847 List of legal baudrate settings for this board.
1849 - CFG_CONSOLE_INFO_QUIET
1850 Suppress display of console information at boot.
1852 - CFG_CONSOLE_IS_IN_ENV
1853 If the board specific function
1854 extern int overwrite_console (void);
1855 returns 1, the stdin, stderr and stdout are switched to the
1856 serial port, else the settings in the environment are used.
1858 - CFG_CONSOLE_OVERWRITE_ROUTINE
1859 Enable the call to overwrite_console().
1861 - CFG_CONSOLE_ENV_OVERWRITE
1862 Enable overwrite of previous console environment settings.
1864 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1865 Begin and End addresses of the area used by the
1869 Enable an alternate, more extensive memory test.
1871 - CFG_MEMTEST_SCRATCH:
1872 Scratch address used by the alternate memory test
1873 You only need to set this if address zero isn't writeable
1875 - CFG_TFTP_LOADADDR:
1876 Default load address for network file downloads
1878 - CFG_LOADS_BAUD_CHANGE:
1879 Enable temporary baudrate change while serial download
1882 Physical start address of SDRAM. _Must_ be 0 here.
1885 Physical start address of Motherboard I/O (if using a
1889 Physical start address of Flash memory.
1892 Physical start address of boot monitor code (set by
1893 make config files to be same as the text base address
1894 (TEXT_BASE) used when linking) - same as
1895 CFG_FLASH_BASE when booting from flash.
1898 Size of memory reserved for monitor code, used to
1899 determine _at_compile_time_ (!) if the environment is
1900 embedded within the U-Boot image, or in a separate
1904 Size of DRAM reserved for malloc() use.
1907 Normally compressed uImages are limited to an
1908 uncompressed size of 8 MBytes. If this is not enough,
1909 you can define CFG_BOOTM_LEN in your board config file
1910 to adjust this setting to your needs.
1913 Maximum size of memory mapped by the startup code of
1914 the Linux kernel; all data that must be processed by
1915 the Linux kernel (bd_info, boot arguments, eventually
1916 initrd image) must be put below this limit.
1918 - CFG_MAX_FLASH_BANKS:
1919 Max number of Flash memory banks
1921 - CFG_MAX_FLASH_SECT:
1922 Max number of sectors on a Flash chip
1924 - CFG_FLASH_ERASE_TOUT:
1925 Timeout for Flash erase operations (in ms)
1927 - CFG_FLASH_WRITE_TOUT:
1928 Timeout for Flash write operations (in ms)
1930 - CFG_FLASH_LOCK_TOUT
1931 Timeout for Flash set sector lock bit operation (in ms)
1933 - CFG_FLASH_UNLOCK_TOUT
1934 Timeout for Flash clear lock bits operation (in ms)
1936 - CFG_FLASH_PROTECTION
1937 If defined, hardware flash sectors protection is used
1938 instead of U-Boot software protection.
1940 - CFG_DIRECT_FLASH_TFTP:
1942 Enable TFTP transfers directly to flash memory;
1943 without this option such a download has to be
1944 performed in two steps: (1) download to RAM, and (2)
1945 copy from RAM to flash.
1947 The two-step approach is usually more reliable, since
1948 you can check if the download worked before you erase
1949 the flash, but in some situations (when sytem RAM is
1950 too limited to allow for a tempory copy of the
1951 downloaded image) this option may be very useful.
1954 Define if the flash driver uses extra elements in the
1955 common flash structure for storing flash geometry.
1957 - CFG_FLASH_CFI_DRIVER
1958 This option also enables the building of the cfi_flash driver
1959 in the drivers directory
1961 - CFG_FLASH_QUIET_TEST
1962 If this option is defined, the common CFI flash doesn't
1963 print it's warning upon not recognized FLASH banks. This
1964 is useful, if some of the configured banks are only
1965 optionally available.
1967 - CONFIG_FLASH_SHOW_PROGRESS
1968 If defined (must be an integer), print out countdown
1969 digits and dots. Recommended value: 45 (9..1) for 80
1970 column displays, 15 (3..1) for 40 column displays.
1972 - CFG_RX_ETH_BUFFER:
1973 Defines the number of ethernet receive buffers. On some
1974 ethernet controllers it is recommended to set this value
1975 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1976 buffers can be full shortly after enabling the interface
1977 on high ethernet traffic.
1978 Defaults to 4 if not defined.
1980 The following definitions that deal with the placement and management
1981 of environment data (variable area); in general, we support the
1982 following configurations:
1984 - CFG_ENV_IS_IN_FLASH:
1986 Define this if the environment is in flash memory.
1988 a) The environment occupies one whole flash sector, which is
1989 "embedded" in the text segment with the U-Boot code. This
1990 happens usually with "bottom boot sector" or "top boot
1991 sector" type flash chips, which have several smaller
1992 sectors at the start or the end. For instance, such a
1993 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1994 such a case you would place the environment in one of the
1995 4 kB sectors - with U-Boot code before and after it. With
1996 "top boot sector" type flash chips, you would put the
1997 environment in one of the last sectors, leaving a gap
1998 between U-Boot and the environment.
2002 Offset of environment data (variable area) to the
2003 beginning of flash memory; for instance, with bottom boot
2004 type flash chips the second sector can be used: the offset
2005 for this sector is given here.
2007 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2011 This is just another way to specify the start address of
2012 the flash sector containing the environment (instead of
2015 - CFG_ENV_SECT_SIZE:
2017 Size of the sector containing the environment.
2020 b) Sometimes flash chips have few, equal sized, BIG sectors.
2021 In such a case you don't want to spend a whole sector for
2026 If you use this in combination with CFG_ENV_IS_IN_FLASH
2027 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2028 of this flash sector for the environment. This saves
2029 memory for the RAM copy of the environment.
2031 It may also save flash memory if you decide to use this
2032 when your environment is "embedded" within U-Boot code,
2033 since then the remainder of the flash sector could be used
2034 for U-Boot code. It should be pointed out that this is
2035 STRONGLY DISCOURAGED from a robustness point of view:
2036 updating the environment in flash makes it always
2037 necessary to erase the WHOLE sector. If something goes
2038 wrong before the contents has been restored from a copy in
2039 RAM, your target system will be dead.
2041 - CFG_ENV_ADDR_REDUND
2044 These settings describe a second storage area used to hold
2045 a redundand copy of the environment data, so that there is
2046 a valid backup copy in case there is a power failure during
2047 a "saveenv" operation.
2049 BE CAREFUL! Any changes to the flash layout, and some changes to the
2050 source code will make it necessary to adapt <board>/u-boot.lds*
2054 - CFG_ENV_IS_IN_NVRAM:
2056 Define this if you have some non-volatile memory device
2057 (NVRAM, battery buffered SRAM) which you want to use for the
2063 These two #defines are used to determin the memory area you
2064 want to use for environment. It is assumed that this memory
2065 can just be read and written to, without any special
2068 BE CAREFUL! The first access to the environment happens quite early
2069 in U-Boot initalization (when we try to get the setting of for the
2070 console baudrate). You *MUST* have mappend your NVRAM area then, or
2073 Please note that even with NVRAM we still use a copy of the
2074 environment in RAM: we could work on NVRAM directly, but we want to
2075 keep settings there always unmodified except somebody uses "saveenv"
2076 to save the current settings.
2079 - CFG_ENV_IS_IN_EEPROM:
2081 Use this if you have an EEPROM or similar serial access
2082 device and a driver for it.
2087 These two #defines specify the offset and size of the
2088 environment area within the total memory of your EEPROM.
2090 - CFG_I2C_EEPROM_ADDR:
2091 If defined, specified the chip address of the EEPROM device.
2092 The default address is zero.
2094 - CFG_EEPROM_PAGE_WRITE_BITS:
2095 If defined, the number of bits used to address bytes in a
2096 single page in the EEPROM device. A 64 byte page, for example
2097 would require six bits.
2099 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2100 If defined, the number of milliseconds to delay between
2101 page writes. The default is zero milliseconds.
2103 - CFG_I2C_EEPROM_ADDR_LEN:
2104 The length in bytes of the EEPROM memory array address. Note
2105 that this is NOT the chip address length!
2107 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2108 EEPROM chips that implement "address overflow" are ones
2109 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2110 address and the extra bits end up in the "chip address" bit
2111 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2114 Note that we consider the length of the address field to
2115 still be one byte because the extra address bits are hidden
2116 in the chip address.
2119 The size in bytes of the EEPROM device.
2122 - CFG_ENV_IS_IN_DATAFLASH:
2124 Define this if you have a DataFlash memory device which you
2125 want to use for the environment.
2131 These three #defines specify the offset and size of the
2132 environment area within the total memory of your DataFlash placed
2133 at the specified address.
2135 - CFG_ENV_IS_IN_NAND:
2137 Define this if you have a NAND device which you want to use
2138 for the environment.
2143 These two #defines specify the offset and size of the environment
2144 area within the first NAND device.
2146 - CFG_ENV_OFFSET_REDUND
2148 This setting describes a second storage area of CFG_ENV_SIZE
2149 size used to hold a redundant copy of the environment data,
2150 so that there is a valid backup copy in case there is a
2151 power failure during a "saveenv" operation.
2153 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2154 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2155 the NAND devices block size.
2157 - CFG_SPI_INIT_OFFSET
2159 Defines offset to the initial SPI buffer area in DPRAM. The
2160 area is used at an early stage (ROM part) if the environment
2161 is configured to reside in the SPI EEPROM: We need a 520 byte
2162 scratch DPRAM area. It is used between the two initialization
2163 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2164 to be a good choice since it makes it far enough from the
2165 start of the data area as well as from the stack pointer.
2167 Please note that the environment is read-only until the monitor
2168 has been relocated to RAM and a RAM copy of the environment has been
2169 created; also, when using EEPROM you will have to use getenv_r()
2170 until then to read environment variables.
2172 The environment is protected by a CRC32 checksum. Before the monitor
2173 is relocated into RAM, as a result of a bad CRC you will be working
2174 with the compiled-in default environment - *silently*!!! [This is
2175 necessary, because the first environment variable we need is the
2176 "baudrate" setting for the console - if we have a bad CRC, we don't
2177 have any device yet where we could complain.]
2179 Note: once the monitor has been relocated, then it will complain if
2180 the default environment is used; a new CRC is computed as soon as you
2181 use the "saveenv" command to store a valid environment.
2183 - CFG_FAULT_ECHO_LINK_DOWN:
2184 Echo the inverted Ethernet link state to the fault LED.
2186 Note: If this option is active, then CFG_FAULT_MII_ADDR
2187 also needs to be defined.
2189 - CFG_FAULT_MII_ADDR:
2190 MII address of the PHY to check for the Ethernet link state.
2192 - CFG_64BIT_VSPRINTF:
2193 Makes vsprintf (and all *printf functions) support printing
2194 of 64bit values by using the L quantifier
2196 - CFG_64BIT_STRTOUL:
2197 Adds simple_strtoull that returns a 64bit value
2199 Low Level (hardware related) configuration options:
2200 ---------------------------------------------------
2202 - CFG_CACHELINE_SIZE:
2203 Cache Line Size of the CPU.
2206 Default address of the IMMR after system reset.
2208 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2209 and RPXsuper) to be able to adjust the position of
2210 the IMMR register after a reset.
2212 - Floppy Disk Support:
2213 CFG_FDC_DRIVE_NUMBER
2215 the default drive number (default value 0)
2219 defines the spacing between fdc chipset registers
2224 defines the offset of register from address. It
2225 depends on which part of the data bus is connected to
2226 the fdc chipset. (default value 0)
2228 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2229 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2232 if CFG_FDC_HW_INIT is defined, then the function
2233 fdc_hw_init() is called at the beginning of the FDC
2234 setup. fdc_hw_init() must be provided by the board
2235 source code. It is used to make hardware dependant
2238 - CFG_IMMR: Physical address of the Internal Memory.
2239 DO NOT CHANGE unless you know exactly what you're
2240 doing! (11-4) [MPC8xx/82xx systems only]
2242 - CFG_INIT_RAM_ADDR:
2244 Start address of memory area that can be used for
2245 initial data and stack; please note that this must be
2246 writable memory that is working WITHOUT special
2247 initialization, i. e. you CANNOT use normal RAM which
2248 will become available only after programming the
2249 memory controller and running certain initialization
2252 U-Boot uses the following memory types:
2253 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2254 - MPC824X: data cache
2255 - PPC4xx: data cache
2257 - CFG_GBL_DATA_OFFSET:
2259 Offset of the initial data structure in the memory
2260 area defined by CFG_INIT_RAM_ADDR. Usually
2261 CFG_GBL_DATA_OFFSET is chosen such that the initial
2262 data is located at the end of the available space
2263 (sometimes written as (CFG_INIT_RAM_END -
2264 CFG_INIT_DATA_SIZE), and the initial stack is just
2265 below that area (growing from (CFG_INIT_RAM_ADDR +
2266 CFG_GBL_DATA_OFFSET) downward.
2269 On the MPC824X (or other systems that use the data
2270 cache for initial memory) the address chosen for
2271 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2272 point to an otherwise UNUSED address space between
2273 the top of RAM and the start of the PCI space.
2275 - CFG_SIUMCR: SIU Module Configuration (11-6)
2277 - CFG_SYPCR: System Protection Control (11-9)
2279 - CFG_TBSCR: Time Base Status and Control (11-26)
2281 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2283 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2285 - CFG_SCCR: System Clock and reset Control Register (15-27)
2287 - CFG_OR_TIMING_SDRAM:
2291 periodic timer for refresh
2293 - CFG_DER: Debug Event Register (37-47)
2295 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2296 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2297 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2299 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2301 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2302 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2303 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2304 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2306 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2307 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2308 Machine Mode Register and Memory Periodic Timer
2309 Prescaler definitions (SDRAM timing)
2311 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2312 enable I2C microcode relocation patch (MPC8xx);
2313 define relocation offset in DPRAM [DSP2]
2315 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2316 enable SMC microcode relocation patch (MPC8xx);
2317 define relocation offset in DPRAM [SMC1]
2319 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2320 enable SPI microcode relocation patch (MPC8xx);
2321 define relocation offset in DPRAM [SCC4]
2324 Use OSCM clock mode on MBX8xx board. Be careful,
2325 wrong setting might damage your board. Read
2326 doc/README.MBX before setting this variable!
2328 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2329 Offset of the bootmode word in DPRAM used by post
2330 (Power On Self Tests). This definition overrides
2331 #define'd default value in commproc.h resp.
2334 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2335 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2336 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2337 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2338 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2339 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2340 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2341 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2342 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2345 Get DDR timing information from an I2C EEPROM. Common
2346 with pluggable memory modules such as SODIMMs
2349 I2C address of the SPD EEPROM
2352 If SPD EEPROM is on an I2C bus other than the first
2353 one, specify here. Note that the value must resolve
2354 to something your driver can deal with.
2356 - CFG_83XX_DDR_USES_CS0
2357 Only for 83xx systems. If specified, then DDR should
2358 be configured using CS0 and CS1 instead of CS2 and CS3.
2360 - CFG_83XX_DDR_USES_CS0
2361 Only for 83xx systems. If specified, then DDR should
2362 be configured using CS0 and CS1 instead of CS2 and CS3.
2364 - CONFIG_ETHER_ON_FEC[12]
2365 Define to enable FEC[12] on a 8xx series processor.
2367 - CONFIG_FEC[12]_PHY
2368 Define to the hardcoded PHY address which corresponds
2369 to the given FEC; i. e.
2370 #define CONFIG_FEC1_PHY 4
2371 means that the PHY with address 4 is connected to FEC1
2373 When set to -1, means to probe for first available.
2375 - CONFIG_FEC[12]_PHY_NORXERR
2376 The PHY does not have a RXERR line (RMII only).
2377 (so program the FEC to ignore it).
2380 Enable RMII mode for all FECs.
2381 Note that this is a global option, we can't
2382 have one FEC in standard MII mode and another in RMII mode.
2384 - CONFIG_CRC32_VERIFY
2385 Add a verify option to the crc32 command.
2388 => crc32 -v <address> <count> <crc32>
2390 Where address/count indicate a memory area
2391 and crc32 is the correct crc32 which the
2395 Add the "loopw" memory command. This only takes effect if
2396 the memory commands are activated globally (CONFIG_CMD_MEM).
2399 Add the "mdc" and "mwc" memory commands. These are cyclic
2404 This command will print 4 bytes (10,11,12,13) each 500 ms.
2406 => mwc.l 100 12345678 10
2407 This command will write 12345678 to address 100 all 10 ms.
2409 This only takes effect if the memory commands are activated
2410 globally (CONFIG_CMD_MEM).
2412 - CONFIG_SKIP_LOWLEVEL_INIT
2413 - CONFIG_SKIP_RELOCATE_UBOOT
2415 [ARM only] If these variables are defined, then
2416 certain low level initializations (like setting up
2417 the memory controller) are omitted and/or U-Boot does
2418 not relocate itself into RAM.
2419 Normally these variables MUST NOT be defined. The
2420 only exception is when U-Boot is loaded (to RAM) by
2421 some other boot loader or by a debugger which
2422 performs these intializations itself.
2425 Building the Software:
2426 ======================
2428 Building U-Boot has been tested in several native build environments
2429 and in many different cross environments. Of course we cannot support
2430 all possibly existing versions of cross development tools in all
2431 (potentially obsolete) versions. In case of tool chain problems we
2432 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2433 which is extensively used to build and test U-Boot.
2435 If you are not using a native environment, it is assumed that you
2436 have GNU cross compiling tools available in your path. In this case,
2437 you must set the environment variable CROSS_COMPILE in your shell.
2438 Note that no changes to the Makefile or any other source files are
2439 necessary. For example using the ELDK on a 4xx CPU, please enter:
2441 $ CROSS_COMPILE=ppc_4xx-
2442 $ export CROSS_COMPILE
2444 U-Boot is intended to be simple to build. After installing the
2445 sources you must configure U-Boot for one specific board type. This
2450 where "NAME_config" is the name of one of the existing configu-
2451 rations; see the main Makefile for supported names.
2453 Note: for some board special configuration names may exist; check if
2454 additional information is available from the board vendor; for
2455 instance, the TQM823L systems are available without (standard)
2456 or with LCD support. You can select such additional "features"
2457 when chosing the configuration, i. e.
2460 - will configure for a plain TQM823L, i. e. no LCD support
2462 make TQM823L_LCD_config
2463 - will configure for a TQM823L with U-Boot console on LCD
2468 Finally, type "make all", and you should get some working U-Boot
2469 images ready for download to / installation on your system:
2471 - "u-boot.bin" is a raw binary image
2472 - "u-boot" is an image in ELF binary format
2473 - "u-boot.srec" is in Motorola S-Record format
2475 By default the build is performed locally and the objects are saved
2476 in the source directory. One of the two methods can be used to change
2477 this behavior and build U-Boot to some external directory:
2479 1. Add O= to the make command line invocations:
2481 make O=/tmp/build distclean
2482 make O=/tmp/build NAME_config
2483 make O=/tmp/build all
2485 2. Set environment variable BUILD_DIR to point to the desired location:
2487 export BUILD_DIR=/tmp/build
2492 Note that the command line "O=" setting overrides the BUILD_DIR environment
2496 Please be aware that the Makefiles assume you are using GNU make, so
2497 for instance on NetBSD you might need to use "gmake" instead of
2501 If the system board that you have is not listed, then you will need
2502 to port U-Boot to your hardware platform. To do this, follow these
2505 1. Add a new configuration option for your board to the toplevel
2506 "Makefile" and to the "MAKEALL" script, using the existing
2507 entries as examples. Note that here and at many other places
2508 boards and other names are listed in alphabetical sort order. Please
2510 2. Create a new directory to hold your board specific code. Add any
2511 files you need. In your board directory, you will need at least
2512 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2513 3. Create a new configuration file "include/configs/<board>.h" for
2515 3. If you're porting U-Boot to a new CPU, then also create a new
2516 directory to hold your CPU specific code. Add any files you need.
2517 4. Run "make <board>_config" with your new name.
2518 5. Type "make", and you should get a working "u-boot.srec" file
2519 to be installed on your target system.
2520 6. Debug and solve any problems that might arise.
2521 [Of course, this last step is much harder than it sounds.]
2524 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2525 ==============================================================
2527 If you have modified U-Boot sources (for instance added a new board
2528 or support for new devices, a new CPU, etc.) you are expected to
2529 provide feedback to the other developers. The feedback normally takes
2530 the form of a "patch", i. e. a context diff against a certain (latest
2531 official or latest in the git repository) version of U-Boot sources.
2533 But before you submit such a patch, please verify that your modifi-
2534 cation did not break existing code. At least make sure that *ALL* of
2535 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2536 just run the "MAKEALL" script, which will configure and build U-Boot
2537 for ALL supported system. Be warned, this will take a while. You can
2538 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2539 environment variable to the script, i. e. to use the ELDK cross tools
2542 CROSS_COMPILE=ppc_8xx- MAKEALL
2544 or to build on a native PowerPC system you can type
2546 CROSS_COMPILE=' ' MAKEALL
2548 When using the MAKEALL script, the default behaviour is to build
2549 U-Boot in the source directory. This location can be changed by
2550 setting the BUILD_DIR environment variable. Also, for each target
2551 built, the MAKEALL script saves two log files (<target>.ERR and
2552 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2553 location can be changed by setting the MAKEALL_LOGDIR environment
2554 variable. For example:
2556 export BUILD_DIR=/tmp/build
2557 export MAKEALL_LOGDIR=/tmp/log
2558 CROSS_COMPILE=ppc_8xx- MAKEALL
2560 With the above settings build objects are saved in the /tmp/build,
2561 log files are saved in the /tmp/log and the source tree remains clean
2562 during the whole build process.
2565 See also "U-Boot Porting Guide" below.
2568 Monitor Commands - Overview:
2569 ============================
2571 go - start application at address 'addr'
2572 run - run commands in an environment variable
2573 bootm - boot application image from memory
2574 bootp - boot image via network using BootP/TFTP protocol
2575 tftpboot- boot image via network using TFTP protocol
2576 and env variables "ipaddr" and "serverip"
2577 (and eventually "gatewayip")
2578 rarpboot- boot image via network using RARP/TFTP protocol
2579 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2580 loads - load S-Record file over serial line
2581 loadb - load binary file over serial line (kermit mode)
2583 mm - memory modify (auto-incrementing)
2584 nm - memory modify (constant address)
2585 mw - memory write (fill)
2587 cmp - memory compare
2588 crc32 - checksum calculation
2589 imd - i2c memory display
2590 imm - i2c memory modify (auto-incrementing)
2591 inm - i2c memory modify (constant address)
2592 imw - i2c memory write (fill)
2593 icrc32 - i2c checksum calculation
2594 iprobe - probe to discover valid I2C chip addresses
2595 iloop - infinite loop on address range
2596 isdram - print SDRAM configuration information
2597 sspi - SPI utility commands
2598 base - print or set address offset
2599 printenv- print environment variables
2600 setenv - set environment variables
2601 saveenv - save environment variables to persistent storage
2602 protect - enable or disable FLASH write protection
2603 erase - erase FLASH memory
2604 flinfo - print FLASH memory information
2605 bdinfo - print Board Info structure
2606 iminfo - print header information for application image
2607 coninfo - print console devices and informations
2608 ide - IDE sub-system
2609 loop - infinite loop on address range
2610 loopw - infinite write loop on address range
2611 mtest - simple RAM test
2612 icache - enable or disable instruction cache
2613 dcache - enable or disable data cache
2614 reset - Perform RESET of the CPU
2615 echo - echo args to console
2616 version - print monitor version
2617 help - print online help
2618 ? - alias for 'help'
2621 Monitor Commands - Detailed Description:
2622 ========================================
2626 For now: just type "help <command>".
2629 Environment Variables:
2630 ======================
2632 U-Boot supports user configuration using Environment Variables which
2633 can be made persistent by saving to Flash memory.
2635 Environment Variables are set using "setenv", printed using
2636 "printenv", and saved to Flash using "saveenv". Using "setenv"
2637 without a value can be used to delete a variable from the
2638 environment. As long as you don't save the environment you are
2639 working with an in-memory copy. In case the Flash area containing the
2640 environment is erased by accident, a default environment is provided.
2642 Some configuration options can be set using Environment Variables:
2644 baudrate - see CONFIG_BAUDRATE
2646 bootdelay - see CONFIG_BOOTDELAY
2648 bootcmd - see CONFIG_BOOTCOMMAND
2650 bootargs - Boot arguments when booting an RTOS image
2652 bootfile - Name of the image to load with TFTP
2654 autoload - if set to "no" (any string beginning with 'n'),
2655 "bootp" will just load perform a lookup of the
2656 configuration from the BOOTP server, but not try to
2657 load any image using TFTP
2659 autostart - if set to "yes", an image loaded using the "bootp",
2660 "rarpboot", "tftpboot" or "diskboot" commands will
2661 be automatically started (by internally calling
2664 If set to "no", a standalone image passed to the
2665 "bootm" command will be copied to the load address
2666 (and eventually uncompressed), but NOT be started.
2667 This can be used to load and uncompress arbitrary
2670 i2cfast - (PPC405GP|PPC405EP only)
2671 if set to 'y' configures Linux I2C driver for fast
2672 mode (400kHZ). This environment variable is used in
2673 initialization code. So, for changes to be effective
2674 it must be saved and board must be reset.
2676 initrd_high - restrict positioning of initrd images:
2677 If this variable is not set, initrd images will be
2678 copied to the highest possible address in RAM; this
2679 is usually what you want since it allows for
2680 maximum initrd size. If for some reason you want to
2681 make sure that the initrd image is loaded below the
2682 CFG_BOOTMAPSZ limit, you can set this environment
2683 variable to a value of "no" or "off" or "0".
2684 Alternatively, you can set it to a maximum upper
2685 address to use (U-Boot will still check that it
2686 does not overwrite the U-Boot stack and data).
2688 For instance, when you have a system with 16 MB
2689 RAM, and want to reserve 4 MB from use by Linux,
2690 you can do this by adding "mem=12M" to the value of
2691 the "bootargs" variable. However, now you must make
2692 sure that the initrd image is placed in the first
2693 12 MB as well - this can be done with
2695 setenv initrd_high 00c00000
2697 If you set initrd_high to 0xFFFFFFFF, this is an
2698 indication to U-Boot that all addresses are legal
2699 for the Linux kernel, including addresses in flash
2700 memory. In this case U-Boot will NOT COPY the
2701 ramdisk at all. This may be useful to reduce the
2702 boot time on your system, but requires that this
2703 feature is supported by your Linux kernel.
2705 ipaddr - IP address; needed for tftpboot command
2707 loadaddr - Default load address for commands like "bootp",
2708 "rarpboot", "tftpboot", "loadb" or "diskboot"
2710 loads_echo - see CONFIG_LOADS_ECHO
2712 serverip - TFTP server IP address; needed for tftpboot command
2714 bootretry - see CONFIG_BOOT_RETRY_TIME
2716 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2718 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2720 ethprime - When CONFIG_NET_MULTI is enabled controls which
2721 interface is used first.
2723 ethact - When CONFIG_NET_MULTI is enabled controls which
2724 interface is currently active. For example you
2725 can do the following
2727 => setenv ethact FEC ETHERNET
2728 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2729 => setenv ethact SCC ETHERNET
2730 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2732 ethrotate - When set to "no" U-Boot does not go through all
2733 available network interfaces.
2734 It just stays at the currently selected interface.
2736 netretry - When set to "no" each network operation will
2737 either succeed or fail without retrying.
2738 When set to "once" the network operation will
2739 fail when all the available network interfaces
2740 are tried once without success.
2741 Useful on scripts which control the retry operation
2744 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2745 if set load address for the npe microcode
2747 tftpsrcport - If this is set, the value is used for TFTP's
2750 tftpdstport - If this is set, the value is used for TFTP's UDP
2751 destination port instead of the Well Know Port 69.
2753 vlan - When set to a value < 4095 the traffic over
2754 ethernet is encapsulated/received over 802.1q
2757 The following environment variables may be used and automatically
2758 updated by the network boot commands ("bootp" and "rarpboot"),
2759 depending the information provided by your boot server:
2761 bootfile - see above
2762 dnsip - IP address of your Domain Name Server
2763 dnsip2 - IP address of your secondary Domain Name Server
2764 gatewayip - IP address of the Gateway (Router) to use
2765 hostname - Target hostname
2767 netmask - Subnet Mask
2768 rootpath - Pathname of the root filesystem on the NFS server
2769 serverip - see above
2772 There are two special Environment Variables:
2774 serial# - contains hardware identification information such
2775 as type string and/or serial number
2776 ethaddr - Ethernet address
2778 These variables can be set only once (usually during manufacturing of
2779 the board). U-Boot refuses to delete or overwrite these variables
2780 once they have been set once.
2783 Further special Environment Variables:
2785 ver - Contains the U-Boot version string as printed
2786 with the "version" command. This variable is
2787 readonly (see CONFIG_VERSION_VARIABLE).
2790 Please note that changes to some configuration parameters may take
2791 only effect after the next boot (yes, that's just like Windoze :-).
2794 Command Line Parsing:
2795 =====================
2797 There are two different command line parsers available with U-Boot:
2798 the old "simple" one, and the much more powerful "hush" shell:
2800 Old, simple command line parser:
2801 --------------------------------
2803 - supports environment variables (through setenv / saveenv commands)
2804 - several commands on one line, separated by ';'
2805 - variable substitution using "... ${name} ..." syntax
2806 - special characters ('$', ';') can be escaped by prefixing with '\',
2808 setenv bootcmd bootm \${address}
2809 - You can also escape text by enclosing in single apostrophes, for example:
2810 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2815 - similar to Bourne shell, with control structures like
2816 if...then...else...fi, for...do...done; while...do...done,
2817 until...do...done, ...
2818 - supports environment ("global") variables (through setenv / saveenv
2819 commands) and local shell variables (through standard shell syntax
2820 "name=value"); only environment variables can be used with "run"
2826 (1) If a command line (or an environment variable executed by a "run"
2827 command) contains several commands separated by semicolon, and
2828 one of these commands fails, then the remaining commands will be
2831 (2) If you execute several variables with one call to run (i. e.
2832 calling run with a list af variables as arguments), any failing
2833 command will cause "run" to terminate, i. e. the remaining
2834 variables are not executed.
2836 Note for Redundant Ethernet Interfaces:
2837 =======================================
2839 Some boards come with redundant ethernet interfaces; U-Boot supports
2840 such configurations and is capable of automatic selection of a
2841 "working" interface when needed. MAC assignment works as follows:
2843 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2844 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2845 "eth1addr" (=>eth1), "eth2addr", ...
2847 If the network interface stores some valid MAC address (for instance
2848 in SROM), this is used as default address if there is NO correspon-
2849 ding setting in the environment; if the corresponding environment
2850 variable is set, this overrides the settings in the card; that means:
2852 o If the SROM has a valid MAC address, and there is no address in the
2853 environment, the SROM's address is used.
2855 o If there is no valid address in the SROM, and a definition in the
2856 environment exists, then the value from the environment variable is
2859 o If both the SROM and the environment contain a MAC address, and
2860 both addresses are the same, this MAC address is used.
2862 o If both the SROM and the environment contain a MAC address, and the
2863 addresses differ, the value from the environment is used and a
2866 o If neither SROM nor the environment contain a MAC address, an error
2873 The "boot" commands of this monitor operate on "image" files which
2874 can be basicly anything, preceeded by a special header; see the
2875 definitions in include/image.h for details; basicly, the header
2876 defines the following image properties:
2878 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2879 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2880 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2881 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2882 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2883 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2884 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2885 * Compression Type (uncompressed, gzip, bzip2)
2891 The header is marked by a special Magic Number, and both the header
2892 and the data portions of the image are secured against corruption by
2899 Although U-Boot should support any OS or standalone application
2900 easily, the main focus has always been on Linux during the design of
2903 U-Boot includes many features that so far have been part of some
2904 special "boot loader" code within the Linux kernel. Also, any
2905 "initrd" images to be used are no longer part of one big Linux image;
2906 instead, kernel and "initrd" are separate images. This implementation
2907 serves several purposes:
2909 - the same features can be used for other OS or standalone
2910 applications (for instance: using compressed images to reduce the
2911 Flash memory footprint)
2913 - it becomes much easier to port new Linux kernel versions because
2914 lots of low-level, hardware dependent stuff are done by U-Boot
2916 - the same Linux kernel image can now be used with different "initrd"
2917 images; of course this also means that different kernel images can
2918 be run with the same "initrd". This makes testing easier (you don't
2919 have to build a new "zImage.initrd" Linux image when you just
2920 change a file in your "initrd"). Also, a field-upgrade of the
2921 software is easier now.
2927 Porting Linux to U-Boot based systems:
2928 ---------------------------------------
2930 U-Boot cannot save you from doing all the necessary modifications to
2931 configure the Linux device drivers for use with your target hardware
2932 (no, we don't intend to provide a full virtual machine interface to
2935 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2937 Just make sure your machine specific header file (for instance
2938 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2939 Information structure as we define in include/u-boot.h, and make
2940 sure that your definition of IMAP_ADDR uses the same value as your
2941 U-Boot configuration in CFG_IMMR.
2944 Configuring the Linux kernel:
2945 -----------------------------
2947 No specific requirements for U-Boot. Make sure you have some root
2948 device (initial ramdisk, NFS) for your target system.
2951 Building a Linux Image:
2952 -----------------------
2954 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2955 not used. If you use recent kernel source, a new build target
2956 "uImage" will exist which automatically builds an image usable by
2957 U-Boot. Most older kernels also have support for a "pImage" target,
2958 which was introduced for our predecessor project PPCBoot and uses a
2959 100% compatible format.
2968 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2969 encapsulate a compressed Linux kernel image with header information,
2970 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2972 * build a standard "vmlinux" kernel image (in ELF binary format):
2974 * convert the kernel into a raw binary image:
2976 ${CROSS_COMPILE}-objcopy -O binary \
2977 -R .note -R .comment \
2978 -S vmlinux linux.bin
2980 * compress the binary image:
2984 * package compressed binary image for U-Boot:
2986 mkimage -A ppc -O linux -T kernel -C gzip \
2987 -a 0 -e 0 -n "Linux Kernel Image" \
2988 -d linux.bin.gz uImage
2991 The "mkimage" tool can also be used to create ramdisk images for use
2992 with U-Boot, either separated from the Linux kernel image, or
2993 combined into one file. "mkimage" encapsulates the images with a 64
2994 byte header containing information about target architecture,
2995 operating system, image type, compression method, entry points, time
2996 stamp, CRC32 checksums, etc.
2998 "mkimage" can be called in two ways: to verify existing images and
2999 print the header information, or to build new images.
3001 In the first form (with "-l" option) mkimage lists the information
3002 contained in the header of an existing U-Boot image; this includes
3003 checksum verification:
3005 tools/mkimage -l image
3006 -l ==> list image header information
3008 The second form (with "-d" option) is used to build a U-Boot image
3009 from a "data file" which is used as image payload:
3011 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3012 -n name -d data_file image
3013 -A ==> set architecture to 'arch'
3014 -O ==> set operating system to 'os'
3015 -T ==> set image type to 'type'
3016 -C ==> set compression type 'comp'
3017 -a ==> set load address to 'addr' (hex)
3018 -e ==> set entry point to 'ep' (hex)
3019 -n ==> set image name to 'name'
3020 -d ==> use image data from 'datafile'
3022 Right now, all Linux kernels for PowerPC systems use the same load
3023 address (0x00000000), but the entry point address depends on the
3026 - 2.2.x kernels have the entry point at 0x0000000C,
3027 - 2.3.x and later kernels have the entry point at 0x00000000.
3029 So a typical call to build a U-Boot image would read:
3031 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3032 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3033 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3034 > examples/uImage.TQM850L
3035 Image Name: 2.4.4 kernel for TQM850L
3036 Created: Wed Jul 19 02:34:59 2000
3037 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3038 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3039 Load Address: 0x00000000
3040 Entry Point: 0x00000000
3042 To verify the contents of the image (or check for corruption):
3044 -> tools/mkimage -l examples/uImage.TQM850L
3045 Image Name: 2.4.4 kernel for TQM850L
3046 Created: Wed Jul 19 02:34:59 2000
3047 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3048 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3049 Load Address: 0x00000000
3050 Entry Point: 0x00000000
3052 NOTE: for embedded systems where boot time is critical you can trade
3053 speed for memory and install an UNCOMPRESSED image instead: this
3054 needs more space in Flash, but boots much faster since it does not
3055 need to be uncompressed:
3057 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3058 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3059 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3060 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3061 > examples/uImage.TQM850L-uncompressed
3062 Image Name: 2.4.4 kernel for TQM850L
3063 Created: Wed Jul 19 02:34:59 2000
3064 Image Type: PowerPC Linux Kernel Image (uncompressed)
3065 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3066 Load Address: 0x00000000
3067 Entry Point: 0x00000000
3070 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3071 when your kernel is intended to use an initial ramdisk:
3073 -> tools/mkimage -n 'Simple Ramdisk Image' \
3074 > -A ppc -O linux -T ramdisk -C gzip \
3075 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3076 Image Name: Simple Ramdisk Image
3077 Created: Wed Jan 12 14:01:50 2000
3078 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3079 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3080 Load Address: 0x00000000
3081 Entry Point: 0x00000000
3084 Installing a Linux Image:
3085 -------------------------
3087 To downloading a U-Boot image over the serial (console) interface,
3088 you must convert the image to S-Record format:
3090 objcopy -I binary -O srec examples/image examples/image.srec
3092 The 'objcopy' does not understand the information in the U-Boot
3093 image header, so the resulting S-Record file will be relative to
3094 address 0x00000000. To load it to a given address, you need to
3095 specify the target address as 'offset' parameter with the 'loads'
3098 Example: install the image to address 0x40100000 (which on the
3099 TQM8xxL is in the first Flash bank):
3101 => erase 40100000 401FFFFF
3107 ## Ready for S-Record download ...
3108 ~>examples/image.srec
3109 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3111 15989 15990 15991 15992
3112 [file transfer complete]
3114 ## Start Addr = 0x00000000
3117 You can check the success of the download using the 'iminfo' command;
3118 this includes a checksum verification so you can be sure no data
3119 corruption happened:
3123 ## Checking Image at 40100000 ...
3124 Image Name: 2.2.13 for initrd on TQM850L
3125 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3126 Data Size: 335725 Bytes = 327 kB = 0 MB
3127 Load Address: 00000000
3128 Entry Point: 0000000c
3129 Verifying Checksum ... OK
3135 The "bootm" command is used to boot an application that is stored in
3136 memory (RAM or Flash). In case of a Linux kernel image, the contents
3137 of the "bootargs" environment variable is passed to the kernel as
3138 parameters. You can check and modify this variable using the
3139 "printenv" and "setenv" commands:
3142 => printenv bootargs
3143 bootargs=root=/dev/ram
3145 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3147 => printenv bootargs
3148 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3151 ## Booting Linux kernel at 40020000 ...
3152 Image Name: 2.2.13 for NFS on TQM850L
3153 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3154 Data Size: 381681 Bytes = 372 kB = 0 MB
3155 Load Address: 00000000
3156 Entry Point: 0000000c
3157 Verifying Checksum ... OK
3158 Uncompressing Kernel Image ... OK
3159 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
3160 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3161 time_init: decrementer frequency = 187500000/60
3162 Calibrating delay loop... 49.77 BogoMIPS
3163 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3166 If you want to boot a Linux kernel with initial ram disk, you pass
3167 the memory addresses of both the kernel and the initrd image (PPBCOOT
3168 format!) to the "bootm" command:
3170 => imi 40100000 40200000
3172 ## Checking Image at 40100000 ...
3173 Image Name: 2.2.13 for initrd on TQM850L
3174 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3175 Data Size: 335725 Bytes = 327 kB = 0 MB
3176 Load Address: 00000000
3177 Entry Point: 0000000c
3178 Verifying Checksum ... OK
3180 ## Checking Image at 40200000 ...
3181 Image Name: Simple Ramdisk Image
3182 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3183 Data Size: 566530 Bytes = 553 kB = 0 MB
3184 Load Address: 00000000
3185 Entry Point: 00000000
3186 Verifying Checksum ... OK
3188 => bootm 40100000 40200000
3189 ## Booting Linux kernel at 40100000 ...
3190 Image Name: 2.2.13 for initrd on TQM850L
3191 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3192 Data Size: 335725 Bytes = 327 kB = 0 MB
3193 Load Address: 00000000
3194 Entry Point: 0000000c
3195 Verifying Checksum ... OK
3196 Uncompressing Kernel Image ... OK
3197 ## Loading RAMDisk Image at 40200000 ...
3198 Image Name: Simple Ramdisk Image
3199 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3200 Data Size: 566530 Bytes = 553 kB = 0 MB
3201 Load Address: 00000000
3202 Entry Point: 00000000
3203 Verifying Checksum ... OK
3204 Loading Ramdisk ... OK
3205 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
3206 Boot arguments: root=/dev/ram
3207 time_init: decrementer frequency = 187500000/60
3208 Calibrating delay loop... 49.77 BogoMIPS
3210 RAMDISK: Compressed image found at block 0
3211 VFS: Mounted root (ext2 filesystem).
3215 Boot Linux and pass a flat device tree:
3218 First, U-Boot must be compiled with the appropriate defines. See the section
3219 titled "Linux Kernel Interface" above for a more in depth explanation. The
3220 following is an example of how to start a kernel and pass an updated
3226 oft=oftrees/mpc8540ads.dtb
3227 => tftp $oftaddr $oft
3228 Speed: 1000, full duplex
3230 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3231 Filename 'oftrees/mpc8540ads.dtb'.
3232 Load address: 0x300000
3235 Bytes transferred = 4106 (100a hex)
3236 => tftp $loadaddr $bootfile
3237 Speed: 1000, full duplex
3239 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3241 Load address: 0x200000
3242 Loading:############
3244 Bytes transferred = 1029407 (fb51f hex)
3249 => bootm $loadaddr - $oftaddr
3250 ## Booting image at 00200000 ...
3251 Image Name: Linux-2.6.17-dirty
3252 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3253 Data Size: 1029343 Bytes = 1005.2 kB
3254 Load Address: 00000000
3255 Entry Point: 00000000
3256 Verifying Checksum ... OK
3257 Uncompressing Kernel Image ... OK
3258 Booting using flat device tree at 0x300000
3259 Using MPC85xx ADS machine description
3260 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3264 More About U-Boot Image Types:
3265 ------------------------------
3267 U-Boot supports the following image types:
3269 "Standalone Programs" are directly runnable in the environment
3270 provided by U-Boot; it is expected that (if they behave
3271 well) you can continue to work in U-Boot after return from
3272 the Standalone Program.
3273 "OS Kernel Images" are usually images of some Embedded OS which
3274 will take over control completely. Usually these programs
3275 will install their own set of exception handlers, device
3276 drivers, set up the MMU, etc. - this means, that you cannot
3277 expect to re-enter U-Boot except by resetting the CPU.
3278 "RAMDisk Images" are more or less just data blocks, and their
3279 parameters (address, size) are passed to an OS kernel that is
3281 "Multi-File Images" contain several images, typically an OS
3282 (Linux) kernel image and one or more data images like
3283 RAMDisks. This construct is useful for instance when you want
3284 to boot over the network using BOOTP etc., where the boot
3285 server provides just a single image file, but you want to get
3286 for instance an OS kernel and a RAMDisk image.
3288 "Multi-File Images" start with a list of image sizes, each
3289 image size (in bytes) specified by an "uint32_t" in network
3290 byte order. This list is terminated by an "(uint32_t)0".
3291 Immediately after the terminating 0 follow the images, one by
3292 one, all aligned on "uint32_t" boundaries (size rounded up to
3293 a multiple of 4 bytes).
3295 "Firmware Images" are binary images containing firmware (like
3296 U-Boot or FPGA images) which usually will be programmed to
3299 "Script files" are command sequences that will be executed by
3300 U-Boot's command interpreter; this feature is especially
3301 useful when you configure U-Boot to use a real shell (hush)
3302 as command interpreter.
3308 One of the features of U-Boot is that you can dynamically load and
3309 run "standalone" applications, which can use some resources of
3310 U-Boot like console I/O functions or interrupt services.
3312 Two simple examples are included with the sources:
3317 'examples/hello_world.c' contains a small "Hello World" Demo
3318 application; it is automatically compiled when you build U-Boot.
3319 It's configured to run at address 0x00040004, so you can play with it
3323 ## Ready for S-Record download ...
3324 ~>examples/hello_world.srec
3325 1 2 3 4 5 6 7 8 9 10 11 ...
3326 [file transfer complete]
3328 ## Start Addr = 0x00040004
3330 => go 40004 Hello World! This is a test.
3331 ## Starting application at 0x00040004 ...
3342 Hit any key to exit ...
3344 ## Application terminated, rc = 0x0
3346 Another example, which demonstrates how to register a CPM interrupt
3347 handler with the U-Boot code, can be found in 'examples/timer.c'.
3348 Here, a CPM timer is set up to generate an interrupt every second.
3349 The interrupt service routine is trivial, just printing a '.'
3350 character, but this is just a demo program. The application can be
3351 controlled by the following keys:
3353 ? - print current values og the CPM Timer registers
3354 b - enable interrupts and start timer
3355 e - stop timer and disable interrupts
3356 q - quit application
3359 ## Ready for S-Record download ...
3360 ~>examples/timer.srec
3361 1 2 3 4 5 6 7 8 9 10 11 ...
3362 [file transfer complete]
3364 ## Start Addr = 0x00040004
3367 ## Starting application at 0x00040004 ...
3370 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3373 [q, b, e, ?] Set interval 1000000 us
3376 [q, b, e, ?] ........
3377 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3380 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3383 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3386 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3388 [q, b, e, ?] ...Stopping timer
3390 [q, b, e, ?] ## Application terminated, rc = 0x0
3396 Over time, many people have reported problems when trying to use the
3397 "minicom" terminal emulation program for serial download. I (wd)
3398 consider minicom to be broken, and recommend not to use it. Under
3399 Unix, I recommend to use C-Kermit for general purpose use (and
3400 especially for kermit binary protocol download ("loadb" command), and
3401 use "cu" for S-Record download ("loads" command).
3403 Nevertheless, if you absolutely want to use it try adding this
3404 configuration to your "File transfer protocols" section:
3406 Name Program Name U/D FullScr IO-Red. Multi
3407 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3408 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3414 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3415 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3417 Building requires a cross environment; it is known to work on
3418 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3419 need gmake since the Makefiles are not compatible with BSD make).
3420 Note that the cross-powerpc package does not install include files;
3421 attempting to build U-Boot will fail because <machine/ansi.h> is
3422 missing. This file has to be installed and patched manually:
3424 # cd /usr/pkg/cross/powerpc-netbsd/include
3426 # ln -s powerpc machine
3427 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3428 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3430 Native builds *don't* work due to incompatibilities between native
3431 and U-Boot include files.
3433 Booting assumes that (the first part of) the image booted is a
3434 stage-2 loader which in turn loads and then invokes the kernel
3435 proper. Loader sources will eventually appear in the NetBSD source
3436 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3437 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3440 Implementation Internals:
3441 =========================
3443 The following is not intended to be a complete description of every
3444 implementation detail. However, it should help to understand the
3445 inner workings of U-Boot and make it easier to port it to custom
3449 Initial Stack, Global Data:
3450 ---------------------------
3452 The implementation of U-Boot is complicated by the fact that U-Boot
3453 starts running out of ROM (flash memory), usually without access to
3454 system RAM (because the memory controller is not initialized yet).
3455 This means that we don't have writable Data or BSS segments, and BSS
3456 is not initialized as zero. To be able to get a C environment working
3457 at all, we have to allocate at least a minimal stack. Implementation
3458 options for this are defined and restricted by the CPU used: Some CPU
3459 models provide on-chip memory (like the IMMR area on MPC8xx and
3460 MPC826x processors), on others (parts of) the data cache can be
3461 locked as (mis-) used as memory, etc.
3463 Chris Hallinan posted a good summary of these issues to the
3464 u-boot-users mailing list:
3466 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3467 From: "Chris Hallinan" <clh@net1plus.com>
3468 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3471 Correct me if I'm wrong, folks, but the way I understand it
3472 is this: Using DCACHE as initial RAM for Stack, etc, does not
3473 require any physical RAM backing up the cache. The cleverness
3474 is that the cache is being used as a temporary supply of
3475 necessary storage before the SDRAM controller is setup. It's
3476 beyond the scope of this list to expain the details, but you
3477 can see how this works by studying the cache architecture and
3478 operation in the architecture and processor-specific manuals.
3480 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3481 is another option for the system designer to use as an
3482 initial stack/ram area prior to SDRAM being available. Either
3483 option should work for you. Using CS 4 should be fine if your
3484 board designers haven't used it for something that would
3485 cause you grief during the initial boot! It is frequently not
3488 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3489 with your processor/board/system design. The default value
3490 you will find in any recent u-boot distribution in
3491 walnut.h should work for you. I'd set it to a value larger
3492 than your SDRAM module. If you have a 64MB SDRAM module, set
3493 it above 400_0000. Just make sure your board has no resources
3494 that are supposed to respond to that address! That code in
3495 start.S has been around a while and should work as is when
3496 you get the config right.
3501 It is essential to remember this, since it has some impact on the C
3502 code for the initialization procedures:
3504 * Initialized global data (data segment) is read-only. Do not attempt
3507 * Do not use any unitialized global data (or implicitely initialized
3508 as zero data - BSS segment) at all - this is undefined, initiali-
3509 zation is performed later (when relocating to RAM).
3511 * Stack space is very limited. Avoid big data buffers or things like
3514 Having only the stack as writable memory limits means we cannot use
3515 normal global data to share information beween the code. But it
3516 turned out that the implementation of U-Boot can be greatly
3517 simplified by making a global data structure (gd_t) available to all
3518 functions. We could pass a pointer to this data as argument to _all_
3519 functions, but this would bloat the code. Instead we use a feature of
3520 the GCC compiler (Global Register Variables) to share the data: we
3521 place a pointer (gd) to the global data into a register which we
3522 reserve for this purpose.
3524 When choosing a register for such a purpose we are restricted by the
3525 relevant (E)ABI specifications for the current architecture, and by
3526 GCC's implementation.
3528 For PowerPC, the following registers have specific use:
3530 R2: reserved for system use
3531 R3-R4: parameter passing and return values
3532 R5-R10: parameter passing
3533 R13: small data area pointer
3537 (U-Boot also uses R14 as internal GOT pointer.)
3539 ==> U-Boot will use R2 to hold a pointer to the global data
3541 Note: on PPC, we could use a static initializer (since the
3542 address of the global data structure is known at compile time),
3543 but it turned out that reserving a register results in somewhat
3544 smaller code - although the code savings are not that big (on
3545 average for all boards 752 bytes for the whole U-Boot image,
3546 624 text + 127 data).
3548 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3549 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3551 ==> U-Boot will use P5 to hold a pointer to the global data
3553 On ARM, the following registers are used:
3555 R0: function argument word/integer result
3556 R1-R3: function argument word
3558 R10: stack limit (used only if stack checking if enabled)
3559 R11: argument (frame) pointer
3560 R12: temporary workspace
3563 R15: program counter
3565 ==> U-Boot will use R8 to hold a pointer to the global data
3567 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3568 or current versions of GCC may "optimize" the code too much.
3573 U-Boot runs in system state and uses physical addresses, i.e. the
3574 MMU is not used either for address mapping nor for memory protection.
3576 The available memory is mapped to fixed addresses using the memory
3577 controller. In this process, a contiguous block is formed for each
3578 memory type (Flash, SDRAM, SRAM), even when it consists of several
3579 physical memory banks.
3581 U-Boot is installed in the first 128 kB of the first Flash bank (on
3582 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3583 booting and sizing and initializing DRAM, the code relocates itself
3584 to the upper end of DRAM. Immediately below the U-Boot code some
3585 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3586 configuration setting]. Below that, a structure with global Board
3587 Info data is placed, followed by the stack (growing downward).
3589 Additionally, some exception handler code is copied to the low 8 kB
3590 of DRAM (0x00000000 ... 0x00001FFF).
3592 So a typical memory configuration with 16 MB of DRAM could look like
3595 0x0000 0000 Exception Vector code
3598 0x0000 2000 Free for Application Use
3604 0x00FB FF20 Monitor Stack (Growing downward)
3605 0x00FB FFAC Board Info Data and permanent copy of global data
3606 0x00FC 0000 Malloc Arena
3609 0x00FE 0000 RAM Copy of Monitor Code
3610 ... eventually: LCD or video framebuffer
3611 ... eventually: pRAM (Protected RAM - unchanged by reset)
3612 0x00FF FFFF [End of RAM]
3615 System Initialization:
3616 ----------------------
3618 In the reset configuration, U-Boot starts at the reset entry point
3619 (on most PowerPC systens at address 0x00000100). Because of the reset
3620 configuration for CS0# this is a mirror of the onboard Flash memory.
3621 To be able to re-map memory U-Boot then jumps to its link address.
3622 To be able to implement the initialization code in C, a (small!)
3623 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3624 which provide such a feature like MPC8xx or MPC8260), or in a locked
3625 part of the data cache. After that, U-Boot initializes the CPU core,
3626 the caches and the SIU.
3628 Next, all (potentially) available memory banks are mapped using a
3629 preliminary mapping. For example, we put them on 512 MB boundaries
3630 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3631 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3632 programmed for SDRAM access. Using the temporary configuration, a
3633 simple memory test is run that determines the size of the SDRAM
3636 When there is more than one SDRAM bank, and the banks are of
3637 different size, the largest is mapped first. For equal size, the first
3638 bank (CS2#) is mapped first. The first mapping is always for address
3639 0x00000000, with any additional banks following immediately to create
3640 contiguous memory starting from 0.
3642 Then, the monitor installs itself at the upper end of the SDRAM area
3643 and allocates memory for use by malloc() and for the global Board
3644 Info data; also, the exception vector code is copied to the low RAM
3645 pages, and the final stack is set up.
3647 Only after this relocation will you have a "normal" C environment;
3648 until that you are restricted in several ways, mostly because you are
3649 running from ROM, and because the code will have to be relocated to a
3653 U-Boot Porting Guide:
3654 ----------------------
3656 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3660 int main (int argc, char *argv[])
3662 sighandler_t no_more_time;
3664 signal (SIGALRM, no_more_time);
3665 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3667 if (available_money > available_manpower) {
3668 pay consultant to port U-Boot;
3672 Download latest U-Boot source;
3674 Subscribe to u-boot-users mailing list;
3677 email ("Hi, I am new to U-Boot, how do I get started?");
3681 Read the README file in the top level directory;
3682 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3683 Read the source, Luke;
3686 if (available_money > toLocalCurrency ($2500)) {
3689 Add a lot of aggravation and time;
3692 Create your own board support subdirectory;
3694 Create your own board config file;
3698 Add / modify source code;
3702 email ("Hi, I am having problems...");
3704 Send patch file to Wolfgang;
3709 void no_more_time (int sig)
3718 All contributions to U-Boot should conform to the Linux kernel
3719 coding style; see the file "Documentation/CodingStyle" and the script
3720 "scripts/Lindent" in your Linux kernel source directory. In sources
3721 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3722 spaces before parameters to function calls) is actually used.
3724 Source files originating from a different project (for example the
3725 MTD subsystem) are generally exempt from these guidelines and are not
3726 reformated to ease subsequent migration to newer versions of those
3729 Please note that U-Boot is implemented in C (and to some small parts in
3730 Assembler); no C++ is used, so please do not use C++ style comments (//)
3733 Please also stick to the following formatting rules:
3734 - remove any trailing white space
3735 - use TAB characters for indentation, not spaces
3736 - make sure NOT to use DOS '\r\n' line feeds
3737 - do not add more than 2 empty lines to source files
3738 - do not add trailing empty lines to source files
3740 Submissions which do not conform to the standards may be returned
3741 with a request to reformat the changes.
3747 Since the number of patches for U-Boot is growing, we need to
3748 establish some rules. Submissions which do not conform to these rules
3749 may be rejected, even when they contain important and valuable stuff.
3751 Patches shall be sent to the u-boot-users mailing list.
3753 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3755 When you send a patch, please include the following information with
3758 * For bug fixes: a description of the bug and how your patch fixes
3759 this bug. Please try to include a way of demonstrating that the
3760 patch actually fixes something.
3762 * For new features: a description of the feature and your
3765 * A CHANGELOG entry as plaintext (separate from the patch)
3767 * For major contributions, your entry to the CREDITS file
3769 * When you add support for a new board, don't forget to add this
3770 board to the MAKEALL script, too.
3772 * If your patch adds new configuration options, don't forget to
3773 document these in the README file.
3775 * The patch itself. If you are using git (which is *strongly*
3776 recommended) you can easily generate the patch using the
3777 "git-format-patch". If you then use "git-send-email" to send it to
3778 the U-Boot mailing list, you will avoid most of the common problems
3779 with some other mail clients.
3781 If you cannot use git, use "diff -purN OLD NEW". If your version of
3782 diff does not support these options, then get the latest version of
3785 The current directory when running this command shall be the parent
3786 directory of the U-Boot source tree (i. e. please make sure that
3787 your patch includes sufficient directory information for the
3790 We prefer patches as plain text. MIME attachments are discouraged,
3791 and compressed attachments must not be used.
3793 * If one logical set of modifications affects or creates several
3794 files, all these changes shall be submitted in a SINGLE patch file.
3796 * Changesets that contain different, unrelated modifications shall be
3797 submitted as SEPARATE patches, one patch per changeset.
3802 * Before sending the patch, run the MAKEALL script on your patched
3803 source tree and make sure that no errors or warnings are reported
3804 for any of the boards.
3806 * Keep your modifications to the necessary minimum: A patch
3807 containing several unrelated changes or arbitrary reformats will be
3808 returned with a request to re-formatting / split it.
3810 * If you modify existing code, make sure that your new code does not
3811 add to the memory footprint of the code ;-) Small is beautiful!
3812 When adding new features, these should compile conditionally only
3813 (using #ifdef), and the resulting code with the new feature
3814 disabled must not need more memory than the old code without your
3817 * Remember that there is a size limit of 40 kB per message on the
3818 u-boot-users mailing list. Bigger patches will be moderated. If
3819 they are reasonable and not bigger than 100 kB, they will be
3820 acknowledged. Even bigger patches should be avoided.
projects / platform / kernel / u-boot.git / blob