2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
140 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
141 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
142 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
143 - mips Files specific to MIPS CPUs
144 - mpc5xx Files specific to Freescale MPC5xx CPUs
145 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
146 - mpc8xx Files specific to Freescale MPC8xx CPUs
147 - mpc8220 Files specific to Freescale MPC8220 CPUs
148 - mpc824x Files specific to Freescale MPC824x CPUs
149 - mpc8260 Files specific to Freescale MPC8260 CPUs
150 - mpc85xx Files specific to Freescale MPC85xx CPUs
151 - nios Files specific to Altera NIOS CPUs
152 - nios2 Files specific to Altera Nios-II CPUs
153 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
154 - pxa Files specific to Intel XScale PXA CPUs
155 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
156 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
157 - disk Code for disk drive partition handling
158 - doc Documentation (don't expect too much)
159 - drivers Commonly used device drivers
160 - dtt Digital Thermometer and Thermostat drivers
161 - examples Example code for standalone applications, etc.
162 - include Header Files
163 - lib_arm Files generic to ARM architecture
164 - lib_avr32 Files generic to AVR32 architecture
165 - lib_generic Files generic to all architectures
166 - lib_i386 Files generic to i386 architecture
167 - lib_m68k Files generic to m68k architecture
168 - lib_mips Files generic to MIPS architecture
169 - lib_nios Files generic to NIOS architecture
170 - lib_ppc Files generic to PowerPC architecture
171 - libfdt Library files to support flattened device trees
172 - net Networking code
173 - post Power On Self Test
174 - rtc Real Time Clock drivers
175 - tools Tools to build S-Record or U-Boot images, etc.
177 Software Configuration:
178 =======================
180 Configuration is usually done using C preprocessor defines; the
181 rationale behind that is to avoid dead code whenever possible.
183 There are two classes of configuration variables:
185 * Configuration _OPTIONS_:
186 These are selectable by the user and have names beginning with
189 * Configuration _SETTINGS_:
190 These depend on the hardware etc. and should not be meddled with if
191 you don't know what you're doing; they have names beginning with
194 Later we will add a configuration tool - probably similar to or even
195 identical to what's used for the Linux kernel. Right now, we have to
196 do the configuration by hand, which means creating some symbolic
197 links and editing some configuration files. We use the TQM8xxL boards
201 Selection of Processor Architecture and Board Type:
202 ---------------------------------------------------
204 For all supported boards there are ready-to-use default
205 configurations available; just type "make <board_name>_config".
207 Example: For a TQM823L module type:
212 For the Cogent platform, you need to specify the cpu type as well;
213 e.g. "make cogent_mpc8xx_config". And also configure the cogent
214 directory according to the instructions in cogent/README.
217 Configuration Options:
218 ----------------------
220 Configuration depends on the combination of board and CPU type; all
221 such information is kept in a configuration file
222 "include/configs/<board_name>.h".
224 Example: For a TQM823L module, all configuration settings are in
225 "include/configs/TQM823L.h".
228 Many of the options are named exactly as the corresponding Linux
229 kernel configuration options. The intention is to make it easier to
230 build a config tool - later.
233 The following options need to be configured:
235 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
237 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
239 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
240 Define exactly one, e.g. CONFIG_ATSTK1002
242 - CPU Module Type: (if CONFIG_COGENT is defined)
243 Define exactly one of
245 --- FIXME --- not tested yet:
246 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
247 CONFIG_CMA287_23, CONFIG_CMA287_50
249 - Motherboard Type: (if CONFIG_COGENT is defined)
250 Define exactly one of
251 CONFIG_CMA101, CONFIG_CMA102
253 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
254 Define one or more of
257 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
258 Define one or more of
259 CONFIG_LCD_HEARTBEAT - update a character position on
260 the lcd display every second with
263 - Board flavour: (if CONFIG_MPC8260ADS is defined)
266 CFG_8260ADS - original MPC8260ADS
267 CFG_8266ADS - MPC8266ADS
268 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
269 CFG_8272ADS - MPC8272ADS
271 - MPC824X Family Member (if CONFIG_MPC824X is defined)
272 Define exactly one of
273 CONFIG_MPC8240, CONFIG_MPC8245
275 - 8xx CPU Options: (if using an MPC8xx cpu)
276 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
277 get_gclk_freq() cannot work
278 e.g. if there is no 32KHz
279 reference PIT/RTC clock
280 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
283 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
286 CONFIG_8xx_CPUCLK_DEFAULT
287 See doc/README.MPC866
291 Define this to measure the actual CPU clock instead
292 of relying on the correctness of the configured
293 values. Mostly useful for board bringup to make sure
294 the PLL is locked at the intended frequency. Note
295 that this requires a (stable) reference clock (32 kHz
296 RTC clock or CFG_8XX_XIN)
298 - Intel Monahans options:
299 CFG_MONAHANS_RUN_MODE_OSC_RATIO
301 Defines the Monahans run mode to oscillator
302 ratio. Valid values are 8, 16, 24, 31. The core
303 frequency is this value multiplied by 13 MHz.
305 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
307 Defines the Monahans turbo mode to oscillator
308 ratio. Valid values are 1 (default if undefined) and
309 2. The core frequency as calculated above is multiplied
312 - Linux Kernel Interface:
315 U-Boot stores all clock information in Hz
316 internally. For binary compatibility with older Linux
317 kernels (which expect the clocks passed in the
318 bd_info data to be in MHz) the environment variable
319 "clocks_in_mhz" can be defined so that U-Boot
320 converts clock data to MHZ before passing it to the
322 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
323 "clocks_in_mhz=1" is automatically included in the
326 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
328 When transfering memsize parameter to linux, some versions
329 expect it to be in bytes, others in MB.
330 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
332 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
334 New kernel versions are expecting firmware settings to be
335 passed using flattened device trees (based on open firmware
339 * New libfdt-based support
340 * Adds the "fdt" command
341 * The bootm command automatically updates the fdt
344 * Deprecated, see CONFIG_OF_LIBFDT
345 * Original ft_build.c-based support
346 * Automatically modifies the dft as part of the bootm command
347 * The environment variable "disable_of", when set,
348 disables this functionality.
350 OF_CPU - The proper name of the cpus node.
351 OF_SOC - The proper name of the soc node.
352 OF_TBCLK - The timebase frequency.
353 OF_STDOUT_PATH - The path to the console device
355 boards with QUICC Engines require OF_QE to set UCC mac addresses
359 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
360 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
361 will have a copy of the bd_t. Space should be
362 pre-allocated in the dts for the bd_t.
364 CONFIG_OF_HAS_UBOOT_ENV
366 * CONFIG_OF_LIBFDT - enables the "fdt env" command
367 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
368 will have a copy of u-boot's environment variables
370 CONFIG_OF_BOARD_SETUP
372 Board code has addition modification that it wants to make
373 to the flat device tree before handing it off to the kernel
377 This define fills in the correct boot cpu in the boot
378 param header, the default value is zero if undefined.
383 Define this if you want support for Amba PrimeCell PL010 UARTs.
387 Define this if you want support for Amba PrimeCell PL011 UARTs.
391 If you have Amba PrimeCell PL011 UARTs, set this variable to
392 the clock speed of the UARTs.
396 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
397 define this to a list of base addresses for each (supported)
398 port. See e.g. include/configs/versatile.h
402 Depending on board, define exactly one serial port
403 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
404 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
405 console by defining CONFIG_8xx_CONS_NONE
407 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
408 port routines must be defined elsewhere
409 (i.e. serial_init(), serial_getc(), ...)
412 Enables console device for a color framebuffer. Needs following
413 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
414 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
416 VIDEO_HW_RECTFILL graphic chip supports
419 VIDEO_HW_BITBLT graphic chip supports
420 bit-blit (cf. smiLynxEM)
421 VIDEO_VISIBLE_COLS visible pixel columns
423 VIDEO_VISIBLE_ROWS visible pixel rows
424 VIDEO_PIXEL_SIZE bytes per pixel
425 VIDEO_DATA_FORMAT graphic data format
426 (0-5, cf. cfb_console.c)
427 VIDEO_FB_ADRS framebuffer address
428 VIDEO_KBD_INIT_FCT keyboard int fct
429 (i.e. i8042_kbd_init())
430 VIDEO_TSTC_FCT test char fct
432 VIDEO_GETC_FCT get char fct
434 CONFIG_CONSOLE_CURSOR cursor drawing on/off
435 (requires blink timer
437 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
438 CONFIG_CONSOLE_TIME display time/date info in
440 (requires CONFIG_CMD_DATE)
441 CONFIG_VIDEO_LOGO display Linux logo in
443 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
444 linux_logo.h for logo.
445 Requires CONFIG_VIDEO_LOGO
446 CONFIG_CONSOLE_EXTRA_INFO
447 addional board info beside
450 When CONFIG_CFB_CONSOLE is defined, video console is
451 default i/o. Serial console can be forced with
452 environment 'console=serial'.
454 When CONFIG_SILENT_CONSOLE is defined, all console
455 messages (by U-Boot and Linux!) can be silenced with
456 the "silent" environment variable. See
457 doc/README.silent for more information.
460 CONFIG_BAUDRATE - in bps
461 Select one of the baudrates listed in
462 CFG_BAUDRATE_TABLE, see below.
463 CFG_BRGCLK_PRESCALE, baudrate prescale
465 - Interrupt driven serial port input:
466 CONFIG_SERIAL_SOFTWARE_FIFO
469 Use an interrupt handler for receiving data on the
470 serial port. It also enables using hardware handshake
471 (RTS/CTS) and UART's built-in FIFO. Set the number of
472 bytes the interrupt driven input buffer should have.
474 Leave undefined to disable this feature, including
475 disable the buffer and hardware handshake.
477 - Console UART Number:
481 If defined internal UART1 (and not UART0) is used
482 as default U-Boot console.
484 - Boot Delay: CONFIG_BOOTDELAY - in seconds
485 Delay before automatically booting the default image;
486 set to -1 to disable autoboot.
488 See doc/README.autoboot for these options that
489 work with CONFIG_BOOTDELAY. None are required.
490 CONFIG_BOOT_RETRY_TIME
491 CONFIG_BOOT_RETRY_MIN
492 CONFIG_AUTOBOOT_KEYED
493 CONFIG_AUTOBOOT_PROMPT
494 CONFIG_AUTOBOOT_DELAY_STR
495 CONFIG_AUTOBOOT_STOP_STR
496 CONFIG_AUTOBOOT_DELAY_STR2
497 CONFIG_AUTOBOOT_STOP_STR2
498 CONFIG_ZERO_BOOTDELAY_CHECK
499 CONFIG_RESET_TO_RETRY
503 Only needed when CONFIG_BOOTDELAY is enabled;
504 define a command string that is automatically executed
505 when no character is read on the console interface
506 within "Boot Delay" after reset.
509 This can be used to pass arguments to the bootm
510 command. The value of CONFIG_BOOTARGS goes into the
511 environment value "bootargs".
513 CONFIG_RAMBOOT and CONFIG_NFSBOOT
514 The value of these goes into the environment as
515 "ramboot" and "nfsboot" respectively, and can be used
516 as a convenience, when switching between booting from
522 When this option is #defined, the existence of the
523 environment variable "preboot" will be checked
524 immediately before starting the CONFIG_BOOTDELAY
525 countdown and/or running the auto-boot command resp.
526 entering interactive mode.
528 This feature is especially useful when "preboot" is
529 automatically generated or modified. For an example
530 see the LWMON board specific code: here "preboot" is
531 modified when the user holds down a certain
532 combination of keys on the (special) keyboard when
535 - Serial Download Echo Mode:
537 If defined to 1, all characters received during a
538 serial download (using the "loads" command) are
539 echoed back. This might be needed by some terminal
540 emulations (like "cu"), but may as well just take
541 time on others. This setting #define's the initial
542 value of the "loads_echo" environment variable.
544 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
546 Select one of the baudrates listed in
547 CFG_BAUDRATE_TABLE, see below.
550 Monitor commands can be included or excluded
551 from the build by using the #include files
552 "config_cmd_all.h" and #undef'ing unwanted
553 commands, or using "config_cmd_default.h"
554 and augmenting with additional #define's
557 The default command configuration includes all commands
558 except those marked below with a "*".
560 CONFIG_CMD_ASKENV * ask for env variable
561 CONFIG_CMD_AUTOSCRIPT Autoscript Support
562 CONFIG_CMD_BDI bdinfo
563 CONFIG_CMD_BEDBUG * Include BedBug Debugger
564 CONFIG_CMD_BMP * BMP support
565 CONFIG_CMD_BSP * Board specific commands
566 CONFIG_CMD_BOOTD bootd
567 CONFIG_CMD_CACHE * icache, dcache
568 CONFIG_CMD_CONSOLE coninfo
569 CONFIG_CMD_DATE * support for RTC, date/time...
570 CONFIG_CMD_DHCP * DHCP support
571 CONFIG_CMD_DIAG * Diagnostics
572 CONFIG_CMD_DOC * Disk-On-Chip Support
573 CONFIG_CMD_DTT * Digital Therm and Thermostat
574 CONFIG_CMD_ECHO echo arguments
575 CONFIG_CMD_EEPROM * EEPROM read/write support
576 CONFIG_CMD_ELF * bootelf, bootvx
577 CONFIG_CMD_ENV saveenv
578 CONFIG_CMD_FDC * Floppy Disk Support
579 CONFIG_CMD_FAT * FAT partition support
580 CONFIG_CMD_FDOS * Dos diskette Support
581 CONFIG_CMD_FLASH flinfo, erase, protect
582 CONFIG_CMD_FPGA FPGA device initialization support
583 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
584 CONFIG_CMD_I2C * I2C serial bus support
585 CONFIG_CMD_IDE * IDE harddisk support
586 CONFIG_CMD_IMI iminfo
587 CONFIG_CMD_IMLS List all found images
588 CONFIG_CMD_IMMAP * IMMR dump support
589 CONFIG_CMD_IRQ * irqinfo
590 CONFIG_CMD_ITEST Integer/string test of 2 values
591 CONFIG_CMD_JFFS2 * JFFS2 Support
592 CONFIG_CMD_KGDB * kgdb
593 CONFIG_CMD_LOADB loadb
594 CONFIG_CMD_LOADS loads
595 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
597 CONFIG_CMD_MISC Misc functions like sleep etc
598 CONFIG_CMD_MMC * MMC memory mapped support
599 CONFIG_CMD_MII * MII utility commands
600 CONFIG_CMD_NAND * NAND support
601 CONFIG_CMD_NET bootp, tftpboot, rarpboot
602 CONFIG_CMD_PCI * pciinfo
603 CONFIG_CMD_PCMCIA * PCMCIA support
604 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
606 CONFIG_CMD_PORTIO * Port I/O
607 CONFIG_CMD_REGINFO * Register dump
608 CONFIG_CMD_RUN run command in env variable
609 CONFIG_CMD_SAVES * save S record dump
610 CONFIG_CMD_SCSI * SCSI Support
611 CONFIG_CMD_SDRAM * print SDRAM configuration information
612 (requires CONFIG_CMD_I2C)
613 CONFIG_CMD_SETGETDCR Support for DCR Register access
615 CONFIG_CMD_SPI * SPI serial bus support
616 CONFIG_CMD_USB * USB support
617 CONFIG_CMD_VFD * VFD support (TRAB)
618 CONFIG_CMD_BSP * Board SPecific functions
619 CONFIG_CMD_CDP * Cisco Discover Protocol support
620 CONFIG_CMD_FSL * Microblaze FSL support
623 EXAMPLE: If you want all functions except of network
624 support you can write:
626 #include "config_cmd_all.h"
627 #undef CONFIG_CMD_NET
630 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
632 Note: Don't enable the "icache" and "dcache" commands
633 (configuration option CONFIG_CMD_CACHE) unless you know
634 what you (and your U-Boot users) are doing. Data
635 cache cannot be enabled on systems like the 8xx or
636 8260 (where accesses to the IMMR region must be
637 uncached), and it cannot be disabled on all other
638 systems where we (mis-) use the data cache to hold an
639 initial stack and some data.
642 XXX - this list needs to get updated!
646 If this variable is defined, it enables watchdog
647 support. There must be support in the platform specific
648 code for a watchdog. For the 8xx and 8260 CPUs, the
649 SIU Watchdog feature is enabled in the SYPCR
653 CONFIG_VERSION_VARIABLE
654 If this variable is defined, an environment variable
655 named "ver" is created by U-Boot showing the U-Boot
656 version as printed by the "version" command.
657 This variable is readonly.
661 When CONFIG_CMD_DATE is selected, the type of the RTC
662 has to be selected, too. Define exactly one of the
665 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
666 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
667 CONFIG_RTC_MC146818 - use MC146818 RTC
668 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
669 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
670 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
671 CONFIG_RTC_DS164x - use Dallas DS164x RTC
672 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
674 Note that if the RTC uses I2C, then the I2C interface
675 must also be configured. See I2C Support, below.
679 When CONFIG_TIMESTAMP is selected, the timestamp
680 (date and time) of an image is printed by image
681 commands like bootm or iminfo. This option is
682 automatically enabled when you select CONFIG_CMD_DATE .
685 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
686 and/or CONFIG_ISO_PARTITION
688 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
689 CONFIG_CMD_SCSI) you must configure support for at least
690 one partition type as well.
693 CONFIG_IDE_RESET_ROUTINE - this is defined in several
694 board configurations files but used nowhere!
696 CONFIG_IDE_RESET - is this is defined, IDE Reset will
697 be performed by calling the function
698 ide_set_reset(int reset)
699 which has to be defined in a board specific file
704 Set this to enable ATAPI support.
709 Set this to enable support for disks larger than 137GB
710 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
711 Whithout these , LBA48 support uses 32bit variables and will 'only'
712 support disks up to 2.1TB.
715 When enabled, makes the IDE subsystem use 64bit sector addresses.
719 At the moment only there is only support for the
720 SYM53C8XX SCSI controller; define
721 CONFIG_SCSI_SYM53C8XX to enable it.
723 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
724 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
725 CFG_SCSI_MAX_LUN] can be adjusted to define the
726 maximum numbers of LUNs, SCSI ID's and target
728 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
730 - NETWORK Support (PCI):
732 Support for Intel 8254x gigabit chips.
735 Support for Intel 82557/82559/82559ER chips.
736 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
737 write routine for first time initialisation.
740 Support for Digital 2114x chips.
741 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
742 modem chip initialisation (KS8761/QS6611).
745 Support for National dp83815 chips.
748 Support for National dp8382[01] gigabit chips.
750 - NETWORK Support (other):
752 CONFIG_DRIVER_LAN91C96
753 Support for SMSC's LAN91C96 chips.
756 Define this to hold the physical address
757 of the LAN91C96's I/O space
759 CONFIG_LAN91C96_USE_32_BIT
760 Define this to enable 32 bit addressing
762 CONFIG_DRIVER_SMC91111
763 Support for SMSC's LAN91C111 chip
766 Define this to hold the physical address
767 of the device (I/O space)
769 CONFIG_SMC_USE_32_BIT
770 Define this if data bus is 32 bits
772 CONFIG_SMC_USE_IOFUNCS
773 Define this to use i/o functions instead of macros
774 (some hardware wont work with macros)
777 At the moment only the UHCI host controller is
778 supported (PIP405, MIP405, MPC5200); define
779 CONFIG_USB_UHCI to enable it.
780 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
781 and define CONFIG_USB_STORAGE to enable the USB
784 Supported are USB Keyboards and USB Floppy drives
786 MPC5200 USB requires additional defines:
788 for 528 MHz Clock: 0x0001bbbb
790 for differential drivers: 0x00001000
791 for single ended drivers: 0x00005000
793 May be defined to allow interrupt polling
794 instead of using asynchronous interrupts
797 Define the below if you wish to use the USB console.
798 Once firmware is rebuilt from a serial console issue the
799 command "setenv stdin usbtty; setenv stdout usbtty" and
800 attach your usb cable. The Unix command "dmesg" should print
801 it has found a new device. The environment variable usbtty
802 can be set to gserial or cdc_acm to enable your device to
803 appear to a USB host as a Linux gserial device or a
804 Common Device Class Abstract Control Model serial device.
805 If you select usbtty = gserial you should be able to enumerate
807 # modprobe usbserial vendor=0xVendorID product=0xProductID
808 else if using cdc_acm, simply setting the environment
809 variable usbtty to be cdc_acm should suffice. The following
810 might be defined in YourBoardName.h
813 Define this to build a UDC device
816 Define this to have a tty type of device available to
817 talk to the UDC device
819 CFG_CONSOLE_IS_IN_ENV
820 Define this if you want stdin, stdout &/or stderr to
824 CFG_USB_EXTC_CLK 0xBLAH
825 Derive USB clock from external clock "blah"
826 - CFG_USB_EXTC_CLK 0x02
828 CFG_USB_BRG_CLK 0xBLAH
829 Derive USB clock from brgclk
830 - CFG_USB_BRG_CLK 0x04
832 If you have a USB-IF assigned VendorID then you may wish to
833 define your own vendor specific values either in BoardName.h
834 or directly in usbd_vendor_info.h. If you don't define
835 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
836 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
837 should pretend to be a Linux device to it's target host.
839 CONFIG_USBD_MANUFACTURER
840 Define this string as the name of your company for
841 - CONFIG_USBD_MANUFACTURER "my company"
843 CONFIG_USBD_PRODUCT_NAME
844 Define this string as the name of your product
845 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
848 Define this as your assigned Vendor ID from the USB
849 Implementors Forum. This *must* be a genuine Vendor ID
850 to avoid polluting the USB namespace.
851 - CONFIG_USBD_VENDORID 0xFFFF
853 CONFIG_USBD_PRODUCTID
854 Define this as the unique Product ID
856 - CONFIG_USBD_PRODUCTID 0xFFFF
860 The MMC controller on the Intel PXA is supported. To
861 enable this define CONFIG_MMC. The MMC can be
862 accessed from the boot prompt by mapping the device
863 to physical memory similar to flash. Command line is
864 enabled with CONFIG_CMD_MMC. The MMC driver also works with
865 the FAT fs. This is enabled with CONFIG_CMD_FAT.
867 - Journaling Flash filesystem support:
868 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
869 CONFIG_JFFS2_NAND_DEV
870 Define these for a default partition on a NAND device
872 CFG_JFFS2_FIRST_SECTOR,
873 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
874 Define these for a default partition on a NOR device
877 Define this to create an own partition. You have to provide a
878 function struct part_info* jffs2_part_info(int part_num)
880 If you define only one JFFS2 partition you may also want to
881 #define CFG_JFFS_SINGLE_PART 1
882 to disable the command chpart. This is the default when you
883 have not defined a custom partition
888 Define this to enable standard (PC-Style) keyboard
892 Standard PC keyboard driver with US (is default) and
893 GERMAN key layout (switch via environment 'keymap=de') support.
894 Export function i8042_kbd_init, i8042_tstc and i8042_getc
895 for cfb_console. Supports cursor blinking.
900 Define this to enable video support (for output to
905 Enable Chips & Technologies 69000 Video chip
907 CONFIG_VIDEO_SMI_LYNXEM
908 Enable Silicon Motion SMI 712/710/810 Video chip. The
909 video output is selected via environment 'videoout'
910 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
913 For the CT69000 and SMI_LYNXEM drivers, videomode is
914 selected via environment 'videomode'. Two diferent ways
916 - "videomode=num" 'num' is a standard LiLo mode numbers.
917 Following standard modes are supported (* is default):
919 Colors 640x480 800x600 1024x768 1152x864 1280x1024
920 -------------+---------------------------------------------
921 8 bits | 0x301* 0x303 0x305 0x161 0x307
922 15 bits | 0x310 0x313 0x316 0x162 0x319
923 16 bits | 0x311 0x314 0x317 0x163 0x31A
924 24 bits | 0x312 0x315 0x318 ? 0x31B
925 -------------+---------------------------------------------
926 (i.e. setenv videomode 317; saveenv; reset;)
928 - "videomode=bootargs" all the video parameters are parsed
929 from the bootargs. (See drivers/video/videomodes.c)
932 CONFIG_VIDEO_SED13806
933 Enable Epson SED13806 driver. This driver supports 8bpp
934 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
935 or CONFIG_VIDEO_SED13806_16BPP
940 Define this to enable a custom keyboard support.
941 This simply calls drv_keyboard_init() which must be
942 defined in your board-specific files.
943 The only board using this so far is RBC823.
945 - LCD Support: CONFIG_LCD
947 Define this to enable LCD support (for output to LCD
948 display); also select one of the supported displays
949 by defining one of these:
951 CONFIG_NEC_NL6448AC33:
953 NEC NL6448AC33-18. Active, color, single scan.
955 CONFIG_NEC_NL6448BC20
957 NEC NL6448BC20-08. 6.5", 640x480.
958 Active, color, single scan.
960 CONFIG_NEC_NL6448BC33_54
962 NEC NL6448BC33-54. 10.4", 640x480.
963 Active, color, single scan.
967 Sharp 320x240. Active, color, single scan.
968 It isn't 16x9, and I am not sure what it is.
970 CONFIG_SHARP_LQ64D341
972 Sharp LQ64D341 display, 640x480.
973 Active, color, single scan.
977 HLD1045 display, 640x480.
978 Active, color, single scan.
982 Optrex CBL50840-2 NF-FW 99 22 M5
984 Hitachi LMG6912RPFC-00T
988 320x240. Black & white.
990 Normally display is black on white background; define
991 CFG_WHITE_ON_BLACK to get it inverted.
993 - Splash Screen Support: CONFIG_SPLASH_SCREEN
995 If this option is set, the environment is checked for
996 a variable "splashimage". If found, the usual display
997 of logo, copyright and system information on the LCD
998 is suppressed and the BMP image at the address
999 specified in "splashimage" is loaded instead. The
1000 console is redirected to the "nulldev", too. This
1001 allows for a "silent" boot where a splash screen is
1002 loaded very quickly after power-on.
1004 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1006 If this option is set, additionally to standard BMP
1007 images, gzipped BMP images can be displayed via the
1008 splashscreen support or the bmp command.
1010 - Compression support:
1013 If this option is set, support for bzip2 compressed
1014 images is included. If not, only uncompressed and gzip
1015 compressed images are supported.
1017 NOTE: the bzip2 algorithm requires a lot of RAM, so
1018 the malloc area (as defined by CFG_MALLOC_LEN) should
1024 The address of PHY on MII bus.
1026 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1028 The clock frequency of the MII bus
1032 If this option is set, support for speed/duplex
1033 detection of Gigabit PHY is included.
1035 CONFIG_PHY_RESET_DELAY
1037 Some PHY like Intel LXT971A need extra delay after
1038 reset before any MII register access is possible.
1039 For such PHY, set this option to the usec delay
1040 required. (minimum 300usec for LXT971A)
1042 CONFIG_PHY_CMD_DELAY (ppc4xx)
1044 Some PHY like Intel LXT971A need extra delay after
1045 command issued before MII status register can be read
1052 Define a default value for ethernet address to use
1053 for the respective ethernet interface, in case this
1054 is not determined automatically.
1059 Define a default value for the IP address to use for
1060 the default ethernet interface, in case this is not
1061 determined through e.g. bootp.
1063 - Server IP address:
1066 Defines a default value for theIP address of a TFTP
1067 server to contact when using the "tftboot" command.
1069 - Multicast TFTP Mode:
1072 Defines whether you want to support multicast TFTP as per
1073 rfc-2090; for example to work with atftp. Lets lots of targets
1074 tftp down the same boot image concurrently. Note: the ethernet
1075 driver in use must provide a function: mcast() to join/leave a
1078 CONFIG_BOOTP_RANDOM_DELAY
1079 - BOOTP Recovery Mode:
1080 CONFIG_BOOTP_RANDOM_DELAY
1082 If you have many targets in a network that try to
1083 boot using BOOTP, you may want to avoid that all
1084 systems send out BOOTP requests at precisely the same
1085 moment (which would happen for instance at recovery
1086 from a power failure, when all systems will try to
1087 boot, thus flooding the BOOTP server. Defining
1088 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1089 inserted before sending out BOOTP requests. The
1090 following delays are inserted then:
1092 1st BOOTP request: delay 0 ... 1 sec
1093 2nd BOOTP request: delay 0 ... 2 sec
1094 3rd BOOTP request: delay 0 ... 4 sec
1096 BOOTP requests: delay 0 ... 8 sec
1098 - DHCP Advanced Options:
1099 You can fine tune the DHCP functionality by defining
1100 CONFIG_BOOTP_* symbols:
1102 CONFIG_BOOTP_SUBNETMASK
1103 CONFIG_BOOTP_GATEWAY
1104 CONFIG_BOOTP_HOSTNAME
1105 CONFIG_BOOTP_NISDOMAIN
1106 CONFIG_BOOTP_BOOTPATH
1107 CONFIG_BOOTP_BOOTFILESIZE
1110 CONFIG_BOOTP_SEND_HOSTNAME
1111 CONFIG_BOOTP_NTPSERVER
1112 CONFIG_BOOTP_TIMEOFFSET
1113 CONFIG_BOOTP_VENDOREX
1115 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1116 environment variable, not the BOOTP server.
1118 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1119 serverip from a DHCP server, it is possible that more
1120 than one DNS serverip is offered to the client.
1121 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1122 serverip will be stored in the additional environment
1123 variable "dnsip2". The first DNS serverip is always
1124 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1127 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1128 to do a dynamic update of a DNS server. To do this, they
1129 need the hostname of the DHCP requester.
1130 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1131 of the "hostname" environment variable is passed as
1132 option 12 to the DHCP server.
1135 CONFIG_CDP_DEVICE_ID
1137 The device id used in CDP trigger frames.
1139 CONFIG_CDP_DEVICE_ID_PREFIX
1141 A two character string which is prefixed to the MAC address
1146 A printf format string which contains the ascii name of
1147 the port. Normally is set to "eth%d" which sets
1148 eth0 for the first ethernet, eth1 for the second etc.
1150 CONFIG_CDP_CAPABILITIES
1152 A 32bit integer which indicates the device capabilities;
1153 0x00000010 for a normal host which does not forwards.
1157 An ascii string containing the version of the software.
1161 An ascii string containing the name of the platform.
1165 A 32bit integer sent on the trigger.
1167 CONFIG_CDP_POWER_CONSUMPTION
1169 A 16bit integer containing the power consumption of the
1170 device in .1 of milliwatts.
1172 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1174 A byte containing the id of the VLAN.
1176 - Status LED: CONFIG_STATUS_LED
1178 Several configurations allow to display the current
1179 status using a LED. For instance, the LED will blink
1180 fast while running U-Boot code, stop blinking as
1181 soon as a reply to a BOOTP request was received, and
1182 start blinking slow once the Linux kernel is running
1183 (supported by a status LED driver in the Linux
1184 kernel). Defining CONFIG_STATUS_LED enables this
1187 - CAN Support: CONFIG_CAN_DRIVER
1189 Defining CONFIG_CAN_DRIVER enables CAN driver support
1190 on those systems that support this (optional)
1191 feature, like the TQM8xxL modules.
1193 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1195 These enable I2C serial bus commands. Defining either of
1196 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1197 include the appropriate I2C driver for the selected cpu.
1199 This will allow you to use i2c commands at the u-boot
1200 command line (as long as you set CONFIG_CMD_I2C in
1201 CONFIG_COMMANDS) and communicate with i2c based realtime
1202 clock chips. See common/cmd_i2c.c for a description of the
1203 command line interface.
1205 CONFIG_I2C_CMD_TREE is a recommended option that places
1206 all I2C commands under a single 'i2c' root command. The
1207 older 'imm', 'imd', 'iprobe' etc. commands are considered
1208 deprecated and may disappear in the future.
1210 CONFIG_HARD_I2C selects a hardware I2C controller.
1212 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1213 bit-banging) driver instead of CPM or similar hardware
1216 There are several other quantities that must also be
1217 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1219 In both cases you will need to define CFG_I2C_SPEED
1220 to be the frequency (in Hz) at which you wish your i2c bus
1221 to run and CFG_I2C_SLAVE to be the address of this node (ie
1222 the cpu's i2c node address).
1224 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1225 sets the cpu up as a master node and so its address should
1226 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1227 p.16-473). So, set CFG_I2C_SLAVE to 0.
1229 That's all that's required for CONFIG_HARD_I2C.
1231 If you use the software i2c interface (CONFIG_SOFT_I2C)
1232 then the following macros need to be defined (examples are
1233 from include/configs/lwmon.h):
1237 (Optional). Any commands necessary to enable the I2C
1238 controller or configure ports.
1240 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1244 (Only for MPC8260 CPU). The I/O port to use (the code
1245 assumes both bits are on the same port). Valid values
1246 are 0..3 for ports A..D.
1250 The code necessary to make the I2C data line active
1251 (driven). If the data line is open collector, this
1254 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1258 The code necessary to make the I2C data line tri-stated
1259 (inactive). If the data line is open collector, this
1262 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1266 Code that returns TRUE if the I2C data line is high,
1269 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1273 If <bit> is TRUE, sets the I2C data line high. If it
1274 is FALSE, it clears it (low).
1276 eg: #define I2C_SDA(bit) \
1277 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1278 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1282 If <bit> is TRUE, sets the I2C clock line high. If it
1283 is FALSE, it clears it (low).
1285 eg: #define I2C_SCL(bit) \
1286 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1287 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1291 This delay is invoked four times per clock cycle so this
1292 controls the rate of data transfer. The data rate thus
1293 is 1 / (I2C_DELAY * 4). Often defined to be something
1296 #define I2C_DELAY udelay(2)
1300 When a board is reset during an i2c bus transfer
1301 chips might think that the current transfer is still
1302 in progress. On some boards it is possible to access
1303 the i2c SCLK line directly, either by using the
1304 processor pin as a GPIO or by having a second pin
1305 connected to the bus. If this option is defined a
1306 custom i2c_init_board() routine in boards/xxx/board.c
1307 is run early in the boot sequence.
1309 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1311 This option enables configuration of bi_iic_fast[] flags
1312 in u-boot bd_info structure based on u-boot environment
1313 variable "i2cfast". (see also i2cfast)
1315 CONFIG_I2C_MULTI_BUS
1317 This option allows the use of multiple I2C buses, each of which
1318 must have a controller. At any point in time, only one bus is
1319 active. To switch to a different bus, use the 'i2c dev' command.
1320 Note that bus numbering is zero-based.
1324 This option specifies a list of I2C devices that will be skipped
1325 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1326 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1327 pairs. Otherwise, specify a 1D array of device addresses
1330 #undef CONFIG_I2C_MULTI_BUS
1331 #define CFG_I2C_NOPROBES {0x50,0x68}
1333 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1335 #define CONFIG_I2C_MULTI_BUS
1336 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1338 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1342 If defined, then this indicates the I2C bus number for DDR SPD.
1343 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1347 If defined, then this indicates the I2C bus number for the RTC.
1348 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1352 If defined, then this indicates the I2C bus number for the DTT.
1353 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1357 Define this option if you want to use Freescale's I2C driver in
1358 drivers/i2c/fsl_i2c.c.
1361 - SPI Support: CONFIG_SPI
1363 Enables SPI driver (so far only tested with
1364 SPI EEPROM, also an instance works with Crystal A/D and
1365 D/As on the SACSng board)
1369 Enables extended (16-bit) SPI EEPROM addressing.
1370 (symmetrical to CONFIG_I2C_X)
1374 Enables a software (bit-bang) SPI driver rather than
1375 using hardware support. This is a general purpose
1376 driver that only requires three general I/O port pins
1377 (two outputs, one input) to function. If this is
1378 defined, the board configuration must define several
1379 SPI configuration items (port pins to use, etc). For
1380 an example, see include/configs/sacsng.h.
1384 Enables a hardware SPI driver for general-purpose reads
1385 and writes. As with CONFIG_SOFT_SPI, the board configuration
1386 must define a list of chip-select function pointers.
1387 Currently supported on some MPC8xxx processors. For an
1388 example, see include/configs/mpc8349emds.h.
1390 - FPGA Support: CONFIG_FPGA
1392 Enables FPGA subsystem.
1394 CONFIG_FPGA_<vendor>
1396 Enables support for specific chip vendors.
1399 CONFIG_FPGA_<family>
1401 Enables support for FPGA family.
1402 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1406 Specify the number of FPGA devices to support.
1408 CFG_FPGA_PROG_FEEDBACK
1410 Enable printing of hash marks during FPGA configuration.
1414 Enable checks on FPGA configuration interface busy
1415 status by the configuration function. This option
1416 will require a board or device specific function to
1421 If defined, a function that provides delays in the FPGA
1422 configuration driver.
1424 CFG_FPGA_CHECK_CTRLC
1425 Allow Control-C to interrupt FPGA configuration
1427 CFG_FPGA_CHECK_ERROR
1429 Check for configuration errors during FPGA bitfile
1430 loading. For example, abort during Virtex II
1431 configuration if the INIT_B line goes low (which
1432 indicated a CRC error).
1436 Maximum time to wait for the INIT_B line to deassert
1437 after PROB_B has been deasserted during a Virtex II
1438 FPGA configuration sequence. The default time is 500
1443 Maximum time to wait for BUSY to deassert during
1444 Virtex II FPGA configuration. The default is 5 mS.
1446 CFG_FPGA_WAIT_CONFIG
1448 Time to wait after FPGA configuration. The default is
1451 - Configuration Management:
1454 If defined, this string will be added to the U-Boot
1455 version information (U_BOOT_VERSION)
1457 - Vendor Parameter Protection:
1459 U-Boot considers the values of the environment
1460 variables "serial#" (Board Serial Number) and
1461 "ethaddr" (Ethernet Address) to be parameters that
1462 are set once by the board vendor / manufacturer, and
1463 protects these variables from casual modification by
1464 the user. Once set, these variables are read-only,
1465 and write or delete attempts are rejected. You can
1466 change this behviour:
1468 If CONFIG_ENV_OVERWRITE is #defined in your config
1469 file, the write protection for vendor parameters is
1470 completely disabled. Anybody can change or delete
1473 Alternatively, if you #define _both_ CONFIG_ETHADDR
1474 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1475 ethernet address is installed in the environment,
1476 which can be changed exactly ONCE by the user. [The
1477 serial# is unaffected by this, i. e. it remains
1483 Define this variable to enable the reservation of
1484 "protected RAM", i. e. RAM which is not overwritten
1485 by U-Boot. Define CONFIG_PRAM to hold the number of
1486 kB you want to reserve for pRAM. You can overwrite
1487 this default value by defining an environment
1488 variable "pram" to the number of kB you want to
1489 reserve. Note that the board info structure will
1490 still show the full amount of RAM. If pRAM is
1491 reserved, a new environment variable "mem" will
1492 automatically be defined to hold the amount of
1493 remaining RAM in a form that can be passed as boot
1494 argument to Linux, for instance like that:
1496 setenv bootargs ... mem=\${mem}
1499 This way you can tell Linux not to use this memory,
1500 either, which results in a memory region that will
1501 not be affected by reboots.
1503 *WARNING* If your board configuration uses automatic
1504 detection of the RAM size, you must make sure that
1505 this memory test is non-destructive. So far, the
1506 following board configurations are known to be
1509 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1510 HERMES, IP860, RPXlite, LWMON, LANTEC,
1511 PCU_E, FLAGADM, TQM8260
1516 Define this variable to stop the system in case of a
1517 fatal error, so that you have to reset it manually.
1518 This is probably NOT a good idea for an embedded
1519 system where you want to system to reboot
1520 automatically as fast as possible, but it may be
1521 useful during development since you can try to debug
1522 the conditions that lead to the situation.
1524 CONFIG_NET_RETRY_COUNT
1526 This variable defines the number of retries for
1527 network operations like ARP, RARP, TFTP, or BOOTP
1528 before giving up the operation. If not defined, a
1529 default value of 5 is used.
1531 - Command Interpreter:
1532 CONFIG_AUTO_COMPLETE
1534 Enable auto completion of commands using TAB.
1536 Note that this feature has NOT been implemented yet
1537 for the "hush" shell.
1542 Define this variable to enable the "hush" shell (from
1543 Busybox) as command line interpreter, thus enabling
1544 powerful command line syntax like
1545 if...then...else...fi conditionals or `&&' and '||'
1546 constructs ("shell scripts").
1548 If undefined, you get the old, much simpler behaviour
1549 with a somewhat smaller memory footprint.
1554 This defines the secondary prompt string, which is
1555 printed when the command interpreter needs more input
1556 to complete a command. Usually "> ".
1560 In the current implementation, the local variables
1561 space and global environment variables space are
1562 separated. Local variables are those you define by
1563 simply typing `name=value'. To access a local
1564 variable later on, you have write `$name' or
1565 `${name}'; to execute the contents of a variable
1566 directly type `$name' at the command prompt.
1568 Global environment variables are those you use
1569 setenv/printenv to work with. To run a command stored
1570 in such a variable, you need to use the run command,
1571 and you must not use the '$' sign to access them.
1573 To store commands and special characters in a
1574 variable, please use double quotation marks
1575 surrounding the whole text of the variable, instead
1576 of the backslashes before semicolons and special
1579 - Commandline Editing and History:
1580 CONFIG_CMDLINE_EDITING
1582 Enable editiong and History functions for interactive
1583 commandline input operations
1585 - Default Environment:
1586 CONFIG_EXTRA_ENV_SETTINGS
1588 Define this to contain any number of null terminated
1589 strings (variable = value pairs) that will be part of
1590 the default environment compiled into the boot image.
1592 For example, place something like this in your
1593 board's config file:
1595 #define CONFIG_EXTRA_ENV_SETTINGS \
1599 Warning: This method is based on knowledge about the
1600 internal format how the environment is stored by the
1601 U-Boot code. This is NOT an official, exported
1602 interface! Although it is unlikely that this format
1603 will change soon, there is no guarantee either.
1604 You better know what you are doing here.
1606 Note: overly (ab)use of the default environment is
1607 discouraged. Make sure to check other ways to preset
1608 the environment like the autoscript function or the
1611 - DataFlash Support:
1612 CONFIG_HAS_DATAFLASH
1614 Defining this option enables DataFlash features and
1615 allows to read/write in Dataflash via the standard
1618 - SystemACE Support:
1621 Adding this option adds support for Xilinx SystemACE
1622 chips attached via some sort of local bus. The address
1623 of the chip must alsh be defined in the
1624 CFG_SYSTEMACE_BASE macro. For example:
1626 #define CONFIG_SYSTEMACE
1627 #define CFG_SYSTEMACE_BASE 0xf0000000
1629 When SystemACE support is added, the "ace" device type
1630 becomes available to the fat commands, i.e. fatls.
1632 - TFTP Fixed UDP Port:
1635 If this is defined, the environment variable tftpsrcp
1636 is used to supply the TFTP UDP source port value.
1637 If tftpsrcp isn't defined, the normal pseudo-random port
1638 number generator is used.
1640 Also, the environment variable tftpdstp is used to supply
1641 the TFTP UDP destination port value. If tftpdstp isn't
1642 defined, the normal port 69 is used.
1644 The purpose for tftpsrcp is to allow a TFTP server to
1645 blindly start the TFTP transfer using the pre-configured
1646 target IP address and UDP port. This has the effect of
1647 "punching through" the (Windows XP) firewall, allowing
1648 the remainder of the TFTP transfer to proceed normally.
1649 A better solution is to properly configure the firewall,
1650 but sometimes that is not allowed.
1652 - Show boot progress:
1653 CONFIG_SHOW_BOOT_PROGRESS
1655 Defining this option allows to add some board-
1656 specific code (calling a user-provided function
1657 "show_boot_progress(int)") that enables you to show
1658 the system's boot progress on some display (for
1659 example, some LED's) on your board. At the moment,
1660 the following checkpoints are implemented:
1662 Legacy uImage format:
1665 1 common/cmd_bootm.c before attempting to boot an image
1666 -1 common/cmd_bootm.c Image header has bad magic number
1667 2 common/cmd_bootm.c Image header has correct magic number
1668 -2 common/cmd_bootm.c Image header has bad checksum
1669 3 common/cmd_bootm.c Image header has correct checksum
1670 -3 common/cmd_bootm.c Image data has bad checksum
1671 4 common/cmd_bootm.c Image data has correct checksum
1672 -4 common/cmd_bootm.c Image is for unsupported architecture
1673 5 common/cmd_bootm.c Architecture check OK
1674 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1675 6 common/cmd_bootm.c Image Type check OK
1676 -6 common/cmd_bootm.c gunzip uncompression error
1677 -7 common/cmd_bootm.c Unimplemented compression type
1678 7 common/cmd_bootm.c Uncompression OK
1679 8 common/cmd_bootm.c No uncompress/copy overwrite error
1680 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1682 9 common/image.c Start initial ramdisk verification
1683 -10 common/image.c Ramdisk header has bad magic number
1684 -11 common/image.c Ramdisk header has bad checksum
1685 10 common/image.c Ramdisk header is OK
1686 -12 common/image.c Ramdisk data has bad checksum
1687 11 common/image.c Ramdisk data has correct checksum
1688 12 common/image.c Ramdisk verification complete, start loading
1689 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1690 13 common/image.c Start multifile image verification
1691 14 common/image.c No initial ramdisk, no multifile, continue.
1693 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1695 -30 lib_ppc/board.c Fatal error, hang the system
1696 -31 post/post.c POST test failed, detected by post_output_backlog()
1697 -32 post/post.c POST test failed, detected by post_run_single()
1699 34 common/cmd_doc.c before loading a Image from a DOC device
1700 -35 common/cmd_doc.c Bad usage of "doc" command
1701 35 common/cmd_doc.c correct usage of "doc" command
1702 -36 common/cmd_doc.c No boot device
1703 36 common/cmd_doc.c correct boot device
1704 -37 common/cmd_doc.c Unknown Chip ID on boot device
1705 37 common/cmd_doc.c correct chip ID found, device available
1706 -38 common/cmd_doc.c Read Error on boot device
1707 38 common/cmd_doc.c reading Image header from DOC device OK
1708 -39 common/cmd_doc.c Image header has bad magic number
1709 39 common/cmd_doc.c Image header has correct magic number
1710 -40 common/cmd_doc.c Error reading Image from DOC device
1711 40 common/cmd_doc.c Image header has correct magic number
1712 41 common/cmd_ide.c before loading a Image from a IDE device
1713 -42 common/cmd_ide.c Bad usage of "ide" command
1714 42 common/cmd_ide.c correct usage of "ide" command
1715 -43 common/cmd_ide.c No boot device
1716 43 common/cmd_ide.c boot device found
1717 -44 common/cmd_ide.c Device not available
1718 44 common/cmd_ide.c Device available
1719 -45 common/cmd_ide.c wrong partition selected
1720 45 common/cmd_ide.c partition selected
1721 -46 common/cmd_ide.c Unknown partition table
1722 46 common/cmd_ide.c valid partition table found
1723 -47 common/cmd_ide.c Invalid partition type
1724 47 common/cmd_ide.c correct partition type
1725 -48 common/cmd_ide.c Error reading Image Header on boot device
1726 48 common/cmd_ide.c reading Image Header from IDE device OK
1727 -49 common/cmd_ide.c Image header has bad magic number
1728 49 common/cmd_ide.c Image header has correct magic number
1729 -50 common/cmd_ide.c Image header has bad checksum
1730 50 common/cmd_ide.c Image header has correct checksum
1731 -51 common/cmd_ide.c Error reading Image from IDE device
1732 51 common/cmd_ide.c reading Image from IDE device OK
1733 52 common/cmd_nand.c before loading a Image from a NAND device
1734 -53 common/cmd_nand.c Bad usage of "nand" command
1735 53 common/cmd_nand.c correct usage of "nand" command
1736 -54 common/cmd_nand.c No boot device
1737 54 common/cmd_nand.c boot device found
1738 -55 common/cmd_nand.c Unknown Chip ID on boot device
1739 55 common/cmd_nand.c correct chip ID found, device available
1740 -56 common/cmd_nand.c Error reading Image Header on boot device
1741 56 common/cmd_nand.c reading Image Header from NAND device OK
1742 -57 common/cmd_nand.c Image header has bad magic number
1743 57 common/cmd_nand.c Image header has correct magic number
1744 -58 common/cmd_nand.c Error reading Image from NAND device
1745 58 common/cmd_nand.c reading Image from NAND device OK
1747 -60 common/env_common.c Environment has a bad CRC, using default
1749 64 net/eth.c starting with Ethernetconfiguration.
1750 -64 net/eth.c no Ethernet found.
1751 65 net/eth.c Ethernet found.
1753 -80 common/cmd_net.c usage wrong
1754 80 common/cmd_net.c before calling NetLoop()
1755 -81 common/cmd_net.c some error in NetLoop() occured
1756 81 common/cmd_net.c NetLoop() back without error
1757 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1758 82 common/cmd_net.c trying automatic boot
1759 83 common/cmd_net.c running autoscript
1760 -83 common/cmd_net.c some error in automatic boot or autoscript
1761 84 common/cmd_net.c end without errors
1766 100 common/cmd_bootm.c Kernel FIT Image has correct format
1767 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1768 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1769 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1770 102 common/cmd_bootm.c Kernel unit name specified
1771 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1772 103 common/cmd_bootm.c Found configuration node
1773 104 common/cmd_bootm.c Got kernel subimage node offset
1774 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1775 105 common/cmd_bootm.c Kernel subimage hash verification OK
1776 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1777 106 common/cmd_bootm.c Architecture check OK
1778 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1779 107 common/cmd_bootm.c Kernel subimge type OK
1780 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1781 108 common/cmd_bootm.c Got kernel subimage data/size
1782 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1783 -109 common/cmd_bootm.c Can't get kernel subimage type
1784 -110 common/cmd_bootm.c Can't get kernel subimage comp
1785 -111 common/cmd_bootm.c Can't get kernel subimage os
1786 -112 common/cmd_bootm.c Can't get kernel subimage load address
1787 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1789 120 common/image.c Start initial ramdisk verification
1790 -120 common/image.c Ramdisk FIT image has incorrect format
1791 121 common/image.c Ramdisk FIT image has correct format
1792 122 common/image.c No Ramdisk subimage unit name, using configuration
1793 -122 common/image.c Can't get configuration for ramdisk subimage
1794 123 common/image.c Ramdisk unit name specified
1795 -124 common/image.c Can't get ramdisk subimage node offset
1796 125 common/image.c Got ramdisk subimage node offset
1797 -125 common/image.c Ramdisk subimage hash verification failed
1798 126 common/image.c Ramdisk subimage hash verification OK
1799 -126 common/image.c Ramdisk subimage for unsupported architecture
1800 127 common/image.c Architecture check OK
1801 -127 common/image.c Can't get ramdisk subimage data/size
1802 128 common/image.c Got ramdisk subimage data/size
1803 129 common/image.c Can't get ramdisk load address
1804 -129 common/image.c Got ramdisk load address
1806 -130 common/cmd_doc.c Icorrect FIT image format
1807 131 common/cmd_doc.c FIT image format OK
1809 -140 common/cmd_ide.c Icorrect FIT image format
1810 141 common/cmd_ide.c FIT image format OK
1812 -150 common/cmd_nand.c Icorrect FIT image format
1813 151 common/cmd_nand.c FIT image format OK
1819 [so far only for SMDK2400 and TRAB boards]
1821 - Modem support endable:
1822 CONFIG_MODEM_SUPPORT
1824 - RTS/CTS Flow control enable:
1827 - Modem debug support:
1828 CONFIG_MODEM_SUPPORT_DEBUG
1830 Enables debugging stuff (char screen[1024], dbg())
1831 for modem support. Useful only with BDI2000.
1833 - Interrupt support (PPC):
1835 There are common interrupt_init() and timer_interrupt()
1836 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1837 for cpu specific initialization. interrupt_init_cpu()
1838 should set decrementer_count to appropriate value. If
1839 cpu resets decrementer automatically after interrupt
1840 (ppc4xx) it should set decrementer_count to zero.
1841 timer_interrupt() calls timer_interrupt_cpu() for cpu
1842 specific handling. If board has watchdog / status_led
1843 / other_activity_monitor it works automatically from
1844 general timer_interrupt().
1848 In the target system modem support is enabled when a
1849 specific key (key combination) is pressed during
1850 power-on. Otherwise U-Boot will boot normally
1851 (autoboot). The key_pressed() fuction is called from
1852 board_init(). Currently key_pressed() is a dummy
1853 function, returning 1 and thus enabling modem
1856 If there are no modem init strings in the
1857 environment, U-Boot proceed to autoboot; the
1858 previous output (banner, info printfs) will be
1861 See also: doc/README.Modem
1864 Configuration Settings:
1865 -----------------------
1867 - CFG_LONGHELP: Defined when you want long help messages included;
1868 undefine this when you're short of memory.
1870 - CFG_PROMPT: This is what U-Boot prints on the console to
1871 prompt for user input.
1873 - CFG_CBSIZE: Buffer size for input from the Console
1875 - CFG_PBSIZE: Buffer size for Console output
1877 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1879 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1880 the application (usually a Linux kernel) when it is
1883 - CFG_BAUDRATE_TABLE:
1884 List of legal baudrate settings for this board.
1886 - CFG_CONSOLE_INFO_QUIET
1887 Suppress display of console information at boot.
1889 - CFG_CONSOLE_IS_IN_ENV
1890 If the board specific function
1891 extern int overwrite_console (void);
1892 returns 1, the stdin, stderr and stdout are switched to the
1893 serial port, else the settings in the environment are used.
1895 - CFG_CONSOLE_OVERWRITE_ROUTINE
1896 Enable the call to overwrite_console().
1898 - CFG_CONSOLE_ENV_OVERWRITE
1899 Enable overwrite of previous console environment settings.
1901 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1902 Begin and End addresses of the area used by the
1906 Enable an alternate, more extensive memory test.
1908 - CFG_MEMTEST_SCRATCH:
1909 Scratch address used by the alternate memory test
1910 You only need to set this if address zero isn't writeable
1912 - CFG_TFTP_LOADADDR:
1913 Default load address for network file downloads
1915 - CFG_LOADS_BAUD_CHANGE:
1916 Enable temporary baudrate change while serial download
1919 Physical start address of SDRAM. _Must_ be 0 here.
1922 Physical start address of Motherboard I/O (if using a
1926 Physical start address of Flash memory.
1929 Physical start address of boot monitor code (set by
1930 make config files to be same as the text base address
1931 (TEXT_BASE) used when linking) - same as
1932 CFG_FLASH_BASE when booting from flash.
1935 Size of memory reserved for monitor code, used to
1936 determine _at_compile_time_ (!) if the environment is
1937 embedded within the U-Boot image, or in a separate
1941 Size of DRAM reserved for malloc() use.
1944 Normally compressed uImages are limited to an
1945 uncompressed size of 8 MBytes. If this is not enough,
1946 you can define CFG_BOOTM_LEN in your board config file
1947 to adjust this setting to your needs.
1950 Maximum size of memory mapped by the startup code of
1951 the Linux kernel; all data that must be processed by
1952 the Linux kernel (bd_info, boot arguments, eventually
1953 initrd image) must be put below this limit.
1955 - CFG_MAX_FLASH_BANKS:
1956 Max number of Flash memory banks
1958 - CFG_MAX_FLASH_SECT:
1959 Max number of sectors on a Flash chip
1961 - CFG_FLASH_ERASE_TOUT:
1962 Timeout for Flash erase operations (in ms)
1964 - CFG_FLASH_WRITE_TOUT:
1965 Timeout for Flash write operations (in ms)
1967 - CFG_FLASH_LOCK_TOUT
1968 Timeout for Flash set sector lock bit operation (in ms)
1970 - CFG_FLASH_UNLOCK_TOUT
1971 Timeout for Flash clear lock bits operation (in ms)
1973 - CFG_FLASH_PROTECTION
1974 If defined, hardware flash sectors protection is used
1975 instead of U-Boot software protection.
1977 - CFG_DIRECT_FLASH_TFTP:
1979 Enable TFTP transfers directly to flash memory;
1980 without this option such a download has to be
1981 performed in two steps: (1) download to RAM, and (2)
1982 copy from RAM to flash.
1984 The two-step approach is usually more reliable, since
1985 you can check if the download worked before you erase
1986 the flash, but in some situations (when sytem RAM is
1987 too limited to allow for a tempory copy of the
1988 downloaded image) this option may be very useful.
1991 Define if the flash driver uses extra elements in the
1992 common flash structure for storing flash geometry.
1994 - CFG_FLASH_CFI_DRIVER
1995 This option also enables the building of the cfi_flash driver
1996 in the drivers directory
1998 - CFG_FLASH_QUIET_TEST
1999 If this option is defined, the common CFI flash doesn't
2000 print it's warning upon not recognized FLASH banks. This
2001 is useful, if some of the configured banks are only
2002 optionally available.
2004 - CFG_RX_ETH_BUFFER:
2005 Defines the number of ethernet receive buffers. On some
2006 ethernet controllers it is recommended to set this value
2007 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2008 buffers can be full shortly after enabling the interface
2009 on high ethernet traffic.
2010 Defaults to 4 if not defined.
2012 The following definitions that deal with the placement and management
2013 of environment data (variable area); in general, we support the
2014 following configurations:
2016 - CFG_ENV_IS_IN_FLASH:
2018 Define this if the environment is in flash memory.
2020 a) The environment occupies one whole flash sector, which is
2021 "embedded" in the text segment with the U-Boot code. This
2022 happens usually with "bottom boot sector" or "top boot
2023 sector" type flash chips, which have several smaller
2024 sectors at the start or the end. For instance, such a
2025 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2026 such a case you would place the environment in one of the
2027 4 kB sectors - with U-Boot code before and after it. With
2028 "top boot sector" type flash chips, you would put the
2029 environment in one of the last sectors, leaving a gap
2030 between U-Boot and the environment.
2034 Offset of environment data (variable area) to the
2035 beginning of flash memory; for instance, with bottom boot
2036 type flash chips the second sector can be used: the offset
2037 for this sector is given here.
2039 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2043 This is just another way to specify the start address of
2044 the flash sector containing the environment (instead of
2047 - CFG_ENV_SECT_SIZE:
2049 Size of the sector containing the environment.
2052 b) Sometimes flash chips have few, equal sized, BIG sectors.
2053 In such a case you don't want to spend a whole sector for
2058 If you use this in combination with CFG_ENV_IS_IN_FLASH
2059 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2060 of this flash sector for the environment. This saves
2061 memory for the RAM copy of the environment.
2063 It may also save flash memory if you decide to use this
2064 when your environment is "embedded" within U-Boot code,
2065 since then the remainder of the flash sector could be used
2066 for U-Boot code. It should be pointed out that this is
2067 STRONGLY DISCOURAGED from a robustness point of view:
2068 updating the environment in flash makes it always
2069 necessary to erase the WHOLE sector. If something goes
2070 wrong before the contents has been restored from a copy in
2071 RAM, your target system will be dead.
2073 - CFG_ENV_ADDR_REDUND
2076 These settings describe a second storage area used to hold
2077 a redundand copy of the environment data, so that there is
2078 a valid backup copy in case there is a power failure during
2079 a "saveenv" operation.
2081 BE CAREFUL! Any changes to the flash layout, and some changes to the
2082 source code will make it necessary to adapt <board>/u-boot.lds*
2086 - CFG_ENV_IS_IN_NVRAM:
2088 Define this if you have some non-volatile memory device
2089 (NVRAM, battery buffered SRAM) which you want to use for the
2095 These two #defines are used to determin the memory area you
2096 want to use for environment. It is assumed that this memory
2097 can just be read and written to, without any special
2100 BE CAREFUL! The first access to the environment happens quite early
2101 in U-Boot initalization (when we try to get the setting of for the
2102 console baudrate). You *MUST* have mappend your NVRAM area then, or
2105 Please note that even with NVRAM we still use a copy of the
2106 environment in RAM: we could work on NVRAM directly, but we want to
2107 keep settings there always unmodified except somebody uses "saveenv"
2108 to save the current settings.
2111 - CFG_ENV_IS_IN_EEPROM:
2113 Use this if you have an EEPROM or similar serial access
2114 device and a driver for it.
2119 These two #defines specify the offset and size of the
2120 environment area within the total memory of your EEPROM.
2122 - CFG_I2C_EEPROM_ADDR:
2123 If defined, specified the chip address of the EEPROM device.
2124 The default address is zero.
2126 - CFG_EEPROM_PAGE_WRITE_BITS:
2127 If defined, the number of bits used to address bytes in a
2128 single page in the EEPROM device. A 64 byte page, for example
2129 would require six bits.
2131 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2132 If defined, the number of milliseconds to delay between
2133 page writes. The default is zero milliseconds.
2135 - CFG_I2C_EEPROM_ADDR_LEN:
2136 The length in bytes of the EEPROM memory array address. Note
2137 that this is NOT the chip address length!
2139 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2140 EEPROM chips that implement "address overflow" are ones
2141 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2142 address and the extra bits end up in the "chip address" bit
2143 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2146 Note that we consider the length of the address field to
2147 still be one byte because the extra address bits are hidden
2148 in the chip address.
2151 The size in bytes of the EEPROM device.
2154 - CFG_ENV_IS_IN_DATAFLASH:
2156 Define this if you have a DataFlash memory device which you
2157 want to use for the environment.
2163 These three #defines specify the offset and size of the
2164 environment area within the total memory of your DataFlash placed
2165 at the specified address.
2167 - CFG_ENV_IS_IN_NAND:
2169 Define this if you have a NAND device which you want to use
2170 for the environment.
2175 These two #defines specify the offset and size of the environment
2176 area within the first NAND device.
2178 - CFG_ENV_OFFSET_REDUND
2180 This setting describes a second storage area of CFG_ENV_SIZE
2181 size used to hold a redundant copy of the environment data,
2182 so that there is a valid backup copy in case there is a
2183 power failure during a "saveenv" operation.
2185 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2186 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2187 the NAND devices block size.
2189 - CFG_SPI_INIT_OFFSET
2191 Defines offset to the initial SPI buffer area in DPRAM. The
2192 area is used at an early stage (ROM part) if the environment
2193 is configured to reside in the SPI EEPROM: We need a 520 byte
2194 scratch DPRAM area. It is used between the two initialization
2195 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2196 to be a good choice since it makes it far enough from the
2197 start of the data area as well as from the stack pointer.
2199 Please note that the environment is read-only until the monitor
2200 has been relocated to RAM and a RAM copy of the environment has been
2201 created; also, when using EEPROM you will have to use getenv_r()
2202 until then to read environment variables.
2204 The environment is protected by a CRC32 checksum. Before the monitor
2205 is relocated into RAM, as a result of a bad CRC you will be working
2206 with the compiled-in default environment - *silently*!!! [This is
2207 necessary, because the first environment variable we need is the
2208 "baudrate" setting for the console - if we have a bad CRC, we don't
2209 have any device yet where we could complain.]
2211 Note: once the monitor has been relocated, then it will complain if
2212 the default environment is used; a new CRC is computed as soon as you
2213 use the "saveenv" command to store a valid environment.
2215 - CFG_FAULT_ECHO_LINK_DOWN:
2216 Echo the inverted Ethernet link state to the fault LED.
2218 Note: If this option is active, then CFG_FAULT_MII_ADDR
2219 also needs to be defined.
2221 - CFG_FAULT_MII_ADDR:
2222 MII address of the PHY to check for the Ethernet link state.
2224 - CFG_64BIT_VSPRINTF:
2225 Makes vsprintf (and all *printf functions) support printing
2226 of 64bit values by using the L quantifier
2228 - CFG_64BIT_STRTOUL:
2229 Adds simple_strtoull that returns a 64bit value
2231 Low Level (hardware related) configuration options:
2232 ---------------------------------------------------
2234 - CFG_CACHELINE_SIZE:
2235 Cache Line Size of the CPU.
2238 Default address of the IMMR after system reset.
2240 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2241 and RPXsuper) to be able to adjust the position of
2242 the IMMR register after a reset.
2244 - Floppy Disk Support:
2245 CFG_FDC_DRIVE_NUMBER
2247 the default drive number (default value 0)
2251 defines the spacing between fdc chipset registers
2256 defines the offset of register from address. It
2257 depends on which part of the data bus is connected to
2258 the fdc chipset. (default value 0)
2260 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2261 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2264 if CFG_FDC_HW_INIT is defined, then the function
2265 fdc_hw_init() is called at the beginning of the FDC
2266 setup. fdc_hw_init() must be provided by the board
2267 source code. It is used to make hardware dependant
2270 - CFG_IMMR: Physical address of the Internal Memory.
2271 DO NOT CHANGE unless you know exactly what you're
2272 doing! (11-4) [MPC8xx/82xx systems only]
2274 - CFG_INIT_RAM_ADDR:
2276 Start address of memory area that can be used for
2277 initial data and stack; please note that this must be
2278 writable memory that is working WITHOUT special
2279 initialization, i. e. you CANNOT use normal RAM which
2280 will become available only after programming the
2281 memory controller and running certain initialization
2284 U-Boot uses the following memory types:
2285 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2286 - MPC824X: data cache
2287 - PPC4xx: data cache
2289 - CFG_GBL_DATA_OFFSET:
2291 Offset of the initial data structure in the memory
2292 area defined by CFG_INIT_RAM_ADDR. Usually
2293 CFG_GBL_DATA_OFFSET is chosen such that the initial
2294 data is located at the end of the available space
2295 (sometimes written as (CFG_INIT_RAM_END -
2296 CFG_INIT_DATA_SIZE), and the initial stack is just
2297 below that area (growing from (CFG_INIT_RAM_ADDR +
2298 CFG_GBL_DATA_OFFSET) downward.
2301 On the MPC824X (or other systems that use the data
2302 cache for initial memory) the address chosen for
2303 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2304 point to an otherwise UNUSED address space between
2305 the top of RAM and the start of the PCI space.
2307 - CFG_SIUMCR: SIU Module Configuration (11-6)
2309 - CFG_SYPCR: System Protection Control (11-9)
2311 - CFG_TBSCR: Time Base Status and Control (11-26)
2313 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2315 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2317 - CFG_SCCR: System Clock and reset Control Register (15-27)
2319 - CFG_OR_TIMING_SDRAM:
2323 periodic timer for refresh
2325 - CFG_DER: Debug Event Register (37-47)
2327 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2328 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2329 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2331 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2333 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2334 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2335 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2336 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2338 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2339 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2340 Machine Mode Register and Memory Periodic Timer
2341 Prescaler definitions (SDRAM timing)
2343 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2344 enable I2C microcode relocation patch (MPC8xx);
2345 define relocation offset in DPRAM [DSP2]
2347 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2348 enable SMC microcode relocation patch (MPC8xx);
2349 define relocation offset in DPRAM [SMC1]
2351 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2352 enable SPI microcode relocation patch (MPC8xx);
2353 define relocation offset in DPRAM [SCC4]
2356 Use OSCM clock mode on MBX8xx board. Be careful,
2357 wrong setting might damage your board. Read
2358 doc/README.MBX before setting this variable!
2360 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2361 Offset of the bootmode word in DPRAM used by post
2362 (Power On Self Tests). This definition overrides
2363 #define'd default value in commproc.h resp.
2366 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2367 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2368 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2369 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2370 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2371 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2372 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2373 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2374 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2377 Get DDR timing information from an I2C EEPROM. Common with pluggable
2378 memory modules such as SODIMMs
2380 I2C address of the SPD EEPROM
2383 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2384 Note that the value must resolve to something your driver can deal with.
2386 - CFG_83XX_DDR_USES_CS0
2387 Only for 83xx systems. If specified, then DDR should be configured
2388 using CS0 and CS1 instead of CS2 and CS3.
2390 - CFG_83XX_DDR_USES_CS0
2391 Only for 83xx systems. If specified, then DDR should be configured
2392 using CS0 and CS1 instead of CS2 and CS3.
2394 - CONFIG_ETHER_ON_FEC[12]
2395 Define to enable FEC[12] on a 8xx series processor.
2397 - CONFIG_FEC[12]_PHY
2398 Define to the hardcoded PHY address which corresponds
2399 to the given FEC; i. e.
2400 #define CONFIG_FEC1_PHY 4
2401 means that the PHY with address 4 is connected to FEC1
2403 When set to -1, means to probe for first available.
2405 - CONFIG_FEC[12]_PHY_NORXERR
2406 The PHY does not have a RXERR line (RMII only).
2407 (so program the FEC to ignore it).
2410 Enable RMII mode for all FECs.
2411 Note that this is a global option, we can't
2412 have one FEC in standard MII mode and another in RMII mode.
2414 - CONFIG_CRC32_VERIFY
2415 Add a verify option to the crc32 command.
2418 => crc32 -v <address> <count> <crc32>
2420 Where address/count indicate a memory area
2421 and crc32 is the correct crc32 which the
2425 Add the "loopw" memory command. This only takes effect if
2426 the memory commands are activated globally (CONFIG_CMD_MEM).
2429 Add the "mdc" and "mwc" memory commands. These are cyclic
2434 This command will print 4 bytes (10,11,12,13) each 500 ms.
2436 => mwc.l 100 12345678 10
2437 This command will write 12345678 to address 100 all 10 ms.
2439 This only takes effect if the memory commands are activated
2440 globally (CONFIG_CMD_MEM).
2442 - CONFIG_SKIP_LOWLEVEL_INIT
2443 - CONFIG_SKIP_RELOCATE_UBOOT
2445 [ARM only] If these variables are defined, then
2446 certain low level initializations (like setting up
2447 the memory controller) are omitted and/or U-Boot does
2448 not relocate itself into RAM.
2449 Normally these variables MUST NOT be defined. The
2450 only exception is when U-Boot is loaded (to RAM) by
2451 some other boot loader or by a debugger which
2452 performs these intializations itself.
2455 Building the Software:
2456 ======================
2458 Building U-Boot has been tested in native PPC environments (on a
2459 PowerBook G3 running LinuxPPC 2000) and in cross environments
2460 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2463 If you are not using a native PPC environment, it is assumed that you
2464 have the GNU cross compiling tools available in your path and named
2465 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2466 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2467 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2470 CROSS_COMPILE = ppc_4xx-
2473 U-Boot is intended to be simple to build. After installing the
2474 sources you must configure U-Boot for one specific board type. This
2479 where "NAME_config" is the name of one of the existing
2480 configurations; see the main Makefile for supported names.
2482 Note: for some board special configuration names may exist; check if
2483 additional information is available from the board vendor; for
2484 instance, the TQM823L systems are available without (standard)
2485 or with LCD support. You can select such additional "features"
2486 when chosing the configuration, i. e.
2489 - will configure for a plain TQM823L, i. e. no LCD support
2491 make TQM823L_LCD_config
2492 - will configure for a TQM823L with U-Boot console on LCD
2497 Finally, type "make all", and you should get some working U-Boot
2498 images ready for download to / installation on your system:
2500 - "u-boot.bin" is a raw binary image
2501 - "u-boot" is an image in ELF binary format
2502 - "u-boot.srec" is in Motorola S-Record format
2504 By default the build is performed locally and the objects are saved
2505 in the source directory. One of the two methods can be used to change
2506 this behavior and build U-Boot to some external directory:
2508 1. Add O= to the make command line invocations:
2510 make O=/tmp/build distclean
2511 make O=/tmp/build NAME_config
2512 make O=/tmp/build all
2514 2. Set environment variable BUILD_DIR to point to the desired location:
2516 export BUILD_DIR=/tmp/build
2521 Note that the command line "O=" setting overrides the BUILD_DIR environment
2525 Please be aware that the Makefiles assume you are using GNU make, so
2526 for instance on NetBSD you might need to use "gmake" instead of
2530 If the system board that you have is not listed, then you will need
2531 to port U-Boot to your hardware platform. To do this, follow these
2534 1. Add a new configuration option for your board to the toplevel
2535 "Makefile" and to the "MAKEALL" script, using the existing
2536 entries as examples. Note that here and at many other places
2537 boards and other names are listed in alphabetical sort order. Please
2539 2. Create a new directory to hold your board specific code. Add any
2540 files you need. In your board directory, you will need at least
2541 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2542 3. Create a new configuration file "include/configs/<board>.h" for
2544 3. If you're porting U-Boot to a new CPU, then also create a new
2545 directory to hold your CPU specific code. Add any files you need.
2546 4. Run "make <board>_config" with your new name.
2547 5. Type "make", and you should get a working "u-boot.srec" file
2548 to be installed on your target system.
2549 6. Debug and solve any problems that might arise.
2550 [Of course, this last step is much harder than it sounds.]
2553 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2554 ==============================================================
2556 If you have modified U-Boot sources (for instance added a new board
2557 or support for new devices, a new CPU, etc.) you are expected to
2558 provide feedback to the other developers. The feedback normally takes
2559 the form of a "patch", i. e. a context diff against a certain (latest
2560 official or latest in CVS) version of U-Boot sources.
2562 But before you submit such a patch, please verify that your modifi-
2563 cation did not break existing code. At least make sure that *ALL* of
2564 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2565 just run the "MAKEALL" script, which will configure and build U-Boot
2566 for ALL supported system. Be warned, this will take a while. You can
2567 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2568 environment variable to the script, i. e. to use the cross tools from
2569 MontaVista's Hard Hat Linux you can type
2571 CROSS_COMPILE=ppc_8xx- MAKEALL
2573 or to build on a native PowerPC system you can type
2575 CROSS_COMPILE=' ' MAKEALL
2577 When using the MAKEALL script, the default behaviour is to build U-Boot
2578 in the source directory. This location can be changed by setting the
2579 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2580 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2581 <source dir>/LOG directory. This default location can be changed by
2582 setting the MAKEALL_LOGDIR environment variable. For example:
2584 export BUILD_DIR=/tmp/build
2585 export MAKEALL_LOGDIR=/tmp/log
2586 CROSS_COMPILE=ppc_8xx- MAKEALL
2588 With the above settings build objects are saved in the /tmp/build, log
2589 files are saved in the /tmp/log and the source tree remains clean during
2590 the whole build process.
2593 See also "U-Boot Porting Guide" below.
2596 Monitor Commands - Overview:
2597 ============================
2599 go - start application at address 'addr'
2600 run - run commands in an environment variable
2601 bootm - boot application image from memory
2602 bootp - boot image via network using BootP/TFTP protocol
2603 tftpboot- boot image via network using TFTP protocol
2604 and env variables "ipaddr" and "serverip"
2605 (and eventually "gatewayip")
2606 rarpboot- boot image via network using RARP/TFTP protocol
2607 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2608 loads - load S-Record file over serial line
2609 loadb - load binary file over serial line (kermit mode)
2611 mm - memory modify (auto-incrementing)
2612 nm - memory modify (constant address)
2613 mw - memory write (fill)
2615 cmp - memory compare
2616 crc32 - checksum calculation
2617 imd - i2c memory display
2618 imm - i2c memory modify (auto-incrementing)
2619 inm - i2c memory modify (constant address)
2620 imw - i2c memory write (fill)
2621 icrc32 - i2c checksum calculation
2622 iprobe - probe to discover valid I2C chip addresses
2623 iloop - infinite loop on address range
2624 isdram - print SDRAM configuration information
2625 sspi - SPI utility commands
2626 base - print or set address offset
2627 printenv- print environment variables
2628 setenv - set environment variables
2629 saveenv - save environment variables to persistent storage
2630 protect - enable or disable FLASH write protection
2631 erase - erase FLASH memory
2632 flinfo - print FLASH memory information
2633 bdinfo - print Board Info structure
2634 iminfo - print header information for application image
2635 coninfo - print console devices and informations
2636 ide - IDE sub-system
2637 loop - infinite loop on address range
2638 loopw - infinite write loop on address range
2639 mtest - simple RAM test
2640 icache - enable or disable instruction cache
2641 dcache - enable or disable data cache
2642 reset - Perform RESET of the CPU
2643 echo - echo args to console
2644 version - print monitor version
2645 help - print online help
2646 ? - alias for 'help'
2649 Monitor Commands - Detailed Description:
2650 ========================================
2654 For now: just type "help <command>".
2657 Environment Variables:
2658 ======================
2660 U-Boot supports user configuration using Environment Variables which
2661 can be made persistent by saving to Flash memory.
2663 Environment Variables are set using "setenv", printed using
2664 "printenv", and saved to Flash using "saveenv". Using "setenv"
2665 without a value can be used to delete a variable from the
2666 environment. As long as you don't save the environment you are
2667 working with an in-memory copy. In case the Flash area containing the
2668 environment is erased by accident, a default environment is provided.
2670 Some configuration options can be set using Environment Variables:
2672 baudrate - see CONFIG_BAUDRATE
2674 bootdelay - see CONFIG_BOOTDELAY
2676 bootcmd - see CONFIG_BOOTCOMMAND
2678 bootargs - Boot arguments when booting an RTOS image
2680 bootfile - Name of the image to load with TFTP
2682 autoload - if set to "no" (any string beginning with 'n'),
2683 "bootp" will just load perform a lookup of the
2684 configuration from the BOOTP server, but not try to
2685 load any image using TFTP
2687 autostart - if set to "yes", an image loaded using the "bootp",
2688 "rarpboot", "tftpboot" or "diskboot" commands will
2689 be automatically started (by internally calling
2692 If set to "no", a standalone image passed to the
2693 "bootm" command will be copied to the load address
2694 (and eventually uncompressed), but NOT be started.
2695 This can be used to load and uncompress arbitrary
2698 i2cfast - (PPC405GP|PPC405EP only)
2699 if set to 'y' configures Linux I2C driver for fast
2700 mode (400kHZ). This environment variable is used in
2701 initialization code. So, for changes to be effective
2702 it must be saved and board must be reset.
2704 initrd_high - restrict positioning of initrd images:
2705 If this variable is not set, initrd images will be
2706 copied to the highest possible address in RAM; this
2707 is usually what you want since it allows for
2708 maximum initrd size. If for some reason you want to
2709 make sure that the initrd image is loaded below the
2710 CFG_BOOTMAPSZ limit, you can set this environment
2711 variable to a value of "no" or "off" or "0".
2712 Alternatively, you can set it to a maximum upper
2713 address to use (U-Boot will still check that it
2714 does not overwrite the U-Boot stack and data).
2716 For instance, when you have a system with 16 MB
2717 RAM, and want to reserve 4 MB from use by Linux,
2718 you can do this by adding "mem=12M" to the value of
2719 the "bootargs" variable. However, now you must make
2720 sure that the initrd image is placed in the first
2721 12 MB as well - this can be done with
2723 setenv initrd_high 00c00000
2725 If you set initrd_high to 0xFFFFFFFF, this is an
2726 indication to U-Boot that all addresses are legal
2727 for the Linux kernel, including addresses in flash
2728 memory. In this case U-Boot will NOT COPY the
2729 ramdisk at all. This may be useful to reduce the
2730 boot time on your system, but requires that this
2731 feature is supported by your Linux kernel.
2733 ipaddr - IP address; needed for tftpboot command
2735 loadaddr - Default load address for commands like "bootp",
2736 "rarpboot", "tftpboot", "loadb" or "diskboot"
2738 loads_echo - see CONFIG_LOADS_ECHO
2740 serverip - TFTP server IP address; needed for tftpboot command
2742 bootretry - see CONFIG_BOOT_RETRY_TIME
2744 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2746 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2748 ethprime - When CONFIG_NET_MULTI is enabled controls which
2749 interface is used first.
2751 ethact - When CONFIG_NET_MULTI is enabled controls which
2752 interface is currently active. For example you
2753 can do the following
2755 => setenv ethact FEC ETHERNET
2756 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2757 => setenv ethact SCC ETHERNET
2758 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2760 ethrotate - When set to "no" U-Boot does not go through all
2761 available network interfaces.
2762 It just stays at the currently selected interface.
2764 netretry - When set to "no" each network operation will
2765 either succeed or fail without retrying.
2766 When set to "once" the network operation will
2767 fail when all the available network interfaces
2768 are tried once without success.
2769 Useful on scripts which control the retry operation
2772 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2773 if set load address for the npe microcode
2775 tftpsrcport - If this is set, the value is used for TFTP's
2778 tftpdstport - If this is set, the value is used for TFTP's UDP
2779 destination port instead of the Well Know Port 69.
2781 vlan - When set to a value < 4095 the traffic over
2782 ethernet is encapsulated/received over 802.1q
2785 The following environment variables may be used and automatically
2786 updated by the network boot commands ("bootp" and "rarpboot"),
2787 depending the information provided by your boot server:
2789 bootfile - see above
2790 dnsip - IP address of your Domain Name Server
2791 dnsip2 - IP address of your secondary Domain Name Server
2792 gatewayip - IP address of the Gateway (Router) to use
2793 hostname - Target hostname
2795 netmask - Subnet Mask
2796 rootpath - Pathname of the root filesystem on the NFS server
2797 serverip - see above
2800 There are two special Environment Variables:
2802 serial# - contains hardware identification information such
2803 as type string and/or serial number
2804 ethaddr - Ethernet address
2806 These variables can be set only once (usually during manufacturing of
2807 the board). U-Boot refuses to delete or overwrite these variables
2808 once they have been set once.
2811 Further special Environment Variables:
2813 ver - Contains the U-Boot version string as printed
2814 with the "version" command. This variable is
2815 readonly (see CONFIG_VERSION_VARIABLE).
2818 Please note that changes to some configuration parameters may take
2819 only effect after the next boot (yes, that's just like Windoze :-).
2822 Command Line Parsing:
2823 =====================
2825 There are two different command line parsers available with U-Boot:
2826 the old "simple" one, and the much more powerful "hush" shell:
2828 Old, simple command line parser:
2829 --------------------------------
2831 - supports environment variables (through setenv / saveenv commands)
2832 - several commands on one line, separated by ';'
2833 - variable substitution using "... ${name} ..." syntax
2834 - special characters ('$', ';') can be escaped by prefixing with '\',
2836 setenv bootcmd bootm \${address}
2837 - You can also escape text by enclosing in single apostrophes, for example:
2838 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2843 - similar to Bourne shell, with control structures like
2844 if...then...else...fi, for...do...done; while...do...done,
2845 until...do...done, ...
2846 - supports environment ("global") variables (through setenv / saveenv
2847 commands) and local shell variables (through standard shell syntax
2848 "name=value"); only environment variables can be used with "run"
2854 (1) If a command line (or an environment variable executed by a "run"
2855 command) contains several commands separated by semicolon, and
2856 one of these commands fails, then the remaining commands will be
2859 (2) If you execute several variables with one call to run (i. e.
2860 calling run with a list af variables as arguments), any failing
2861 command will cause "run" to terminate, i. e. the remaining
2862 variables are not executed.
2864 Note for Redundant Ethernet Interfaces:
2865 =======================================
2867 Some boards come with redundant ethernet interfaces; U-Boot supports
2868 such configurations and is capable of automatic selection of a
2869 "working" interface when needed. MAC assignment works as follows:
2871 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2872 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2873 "eth1addr" (=>eth1), "eth2addr", ...
2875 If the network interface stores some valid MAC address (for instance
2876 in SROM), this is used as default address if there is NO correspon-
2877 ding setting in the environment; if the corresponding environment
2878 variable is set, this overrides the settings in the card; that means:
2880 o If the SROM has a valid MAC address, and there is no address in the
2881 environment, the SROM's address is used.
2883 o If there is no valid address in the SROM, and a definition in the
2884 environment exists, then the value from the environment variable is
2887 o If both the SROM and the environment contain a MAC address, and
2888 both addresses are the same, this MAC address is used.
2890 o If both the SROM and the environment contain a MAC address, and the
2891 addresses differ, the value from the environment is used and a
2894 o If neither SROM nor the environment contain a MAC address, an error
2901 The "boot" commands of this monitor operate on "image" files which
2902 can be basicly anything, preceeded by a special header; see the
2903 definitions in include/image.h for details; basicly, the header
2904 defines the following image properties:
2906 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2907 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2908 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2909 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2910 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2911 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2912 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2913 * Compression Type (uncompressed, gzip, bzip2)
2919 The header is marked by a special Magic Number, and both the header
2920 and the data portions of the image are secured against corruption by
2927 Although U-Boot should support any OS or standalone application
2928 easily, the main focus has always been on Linux during the design of
2931 U-Boot includes many features that so far have been part of some
2932 special "boot loader" code within the Linux kernel. Also, any
2933 "initrd" images to be used are no longer part of one big Linux image;
2934 instead, kernel and "initrd" are separate images. This implementation
2935 serves several purposes:
2937 - the same features can be used for other OS or standalone
2938 applications (for instance: using compressed images to reduce the
2939 Flash memory footprint)
2941 - it becomes much easier to port new Linux kernel versions because
2942 lots of low-level, hardware dependent stuff are done by U-Boot
2944 - the same Linux kernel image can now be used with different "initrd"
2945 images; of course this also means that different kernel images can
2946 be run with the same "initrd". This makes testing easier (you don't
2947 have to build a new "zImage.initrd" Linux image when you just
2948 change a file in your "initrd"). Also, a field-upgrade of the
2949 software is easier now.
2955 Porting Linux to U-Boot based systems:
2956 ---------------------------------------
2958 U-Boot cannot save you from doing all the necessary modifications to
2959 configure the Linux device drivers for use with your target hardware
2960 (no, we don't intend to provide a full virtual machine interface to
2963 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2965 Just make sure your machine specific header file (for instance
2966 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2967 Information structure as we define in include/u-boot.h, and make
2968 sure that your definition of IMAP_ADDR uses the same value as your
2969 U-Boot configuration in CFG_IMMR.
2972 Configuring the Linux kernel:
2973 -----------------------------
2975 No specific requirements for U-Boot. Make sure you have some root
2976 device (initial ramdisk, NFS) for your target system.
2979 Building a Linux Image:
2980 -----------------------
2982 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2983 not used. If you use recent kernel source, a new build target
2984 "uImage" will exist which automatically builds an image usable by
2985 U-Boot. Most older kernels also have support for a "pImage" target,
2986 which was introduced for our predecessor project PPCBoot and uses a
2987 100% compatible format.
2996 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2997 encapsulate a compressed Linux kernel image with header information,
2998 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3000 * build a standard "vmlinux" kernel image (in ELF binary format):
3002 * convert the kernel into a raw binary image:
3004 ${CROSS_COMPILE}-objcopy -O binary \
3005 -R .note -R .comment \
3006 -S vmlinux linux.bin
3008 * compress the binary image:
3012 * package compressed binary image for U-Boot:
3014 mkimage -A ppc -O linux -T kernel -C gzip \
3015 -a 0 -e 0 -n "Linux Kernel Image" \
3016 -d linux.bin.gz uImage
3019 The "mkimage" tool can also be used to create ramdisk images for use
3020 with U-Boot, either separated from the Linux kernel image, or
3021 combined into one file. "mkimage" encapsulates the images with a 64
3022 byte header containing information about target architecture,
3023 operating system, image type, compression method, entry points, time
3024 stamp, CRC32 checksums, etc.
3026 "mkimage" can be called in two ways: to verify existing images and
3027 print the header information, or to build new images.
3029 In the first form (with "-l" option) mkimage lists the information
3030 contained in the header of an existing U-Boot image; this includes
3031 checksum verification:
3033 tools/mkimage -l image
3034 -l ==> list image header information
3036 The second form (with "-d" option) is used to build a U-Boot image
3037 from a "data file" which is used as image payload:
3039 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3040 -n name -d data_file image
3041 -A ==> set architecture to 'arch'
3042 -O ==> set operating system to 'os'
3043 -T ==> set image type to 'type'
3044 -C ==> set compression type 'comp'
3045 -a ==> set load address to 'addr' (hex)
3046 -e ==> set entry point to 'ep' (hex)
3047 -n ==> set image name to 'name'
3048 -d ==> use image data from 'datafile'
3050 Right now, all Linux kernels for PowerPC systems use the same load
3051 address (0x00000000), but the entry point address depends on the
3054 - 2.2.x kernels have the entry point at 0x0000000C,
3055 - 2.3.x and later kernels have the entry point at 0x00000000.
3057 So a typical call to build a U-Boot image would read:
3059 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3060 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3061 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3062 > examples/uImage.TQM850L
3063 Image Name: 2.4.4 kernel for TQM850L
3064 Created: Wed Jul 19 02:34:59 2000
3065 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3066 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3067 Load Address: 0x00000000
3068 Entry Point: 0x00000000
3070 To verify the contents of the image (or check for corruption):
3072 -> tools/mkimage -l examples/uImage.TQM850L
3073 Image Name: 2.4.4 kernel for TQM850L
3074 Created: Wed Jul 19 02:34:59 2000
3075 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3076 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3077 Load Address: 0x00000000
3078 Entry Point: 0x00000000
3080 NOTE: for embedded systems where boot time is critical you can trade
3081 speed for memory and install an UNCOMPRESSED image instead: this
3082 needs more space in Flash, but boots much faster since it does not
3083 need to be uncompressed:
3085 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3086 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3087 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3088 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3089 > examples/uImage.TQM850L-uncompressed
3090 Image Name: 2.4.4 kernel for TQM850L
3091 Created: Wed Jul 19 02:34:59 2000
3092 Image Type: PowerPC Linux Kernel Image (uncompressed)
3093 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3094 Load Address: 0x00000000
3095 Entry Point: 0x00000000
3098 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3099 when your kernel is intended to use an initial ramdisk:
3101 -> tools/mkimage -n 'Simple Ramdisk Image' \
3102 > -A ppc -O linux -T ramdisk -C gzip \
3103 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3104 Image Name: Simple Ramdisk Image
3105 Created: Wed Jan 12 14:01:50 2000
3106 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3107 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3108 Load Address: 0x00000000
3109 Entry Point: 0x00000000
3112 Installing a Linux Image:
3113 -------------------------
3115 To downloading a U-Boot image over the serial (console) interface,
3116 you must convert the image to S-Record format:
3118 objcopy -I binary -O srec examples/image examples/image.srec
3120 The 'objcopy' does not understand the information in the U-Boot
3121 image header, so the resulting S-Record file will be relative to
3122 address 0x00000000. To load it to a given address, you need to
3123 specify the target address as 'offset' parameter with the 'loads'
3126 Example: install the image to address 0x40100000 (which on the
3127 TQM8xxL is in the first Flash bank):
3129 => erase 40100000 401FFFFF
3135 ## Ready for S-Record download ...
3136 ~>examples/image.srec
3137 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3139 15989 15990 15991 15992
3140 [file transfer complete]
3142 ## Start Addr = 0x00000000
3145 You can check the success of the download using the 'iminfo' command;
3146 this includes a checksum verification so you can be sure no data
3147 corruption happened:
3151 ## Checking Image at 40100000 ...
3152 Image Name: 2.2.13 for initrd on TQM850L
3153 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3154 Data Size: 335725 Bytes = 327 kB = 0 MB
3155 Load Address: 00000000
3156 Entry Point: 0000000c
3157 Verifying Checksum ... OK
3163 The "bootm" command is used to boot an application that is stored in
3164 memory (RAM or Flash). In case of a Linux kernel image, the contents
3165 of the "bootargs" environment variable is passed to the kernel as
3166 parameters. You can check and modify this variable using the
3167 "printenv" and "setenv" commands:
3170 => printenv bootargs
3171 bootargs=root=/dev/ram
3173 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3175 => printenv bootargs
3176 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3179 ## Booting Linux kernel at 40020000 ...
3180 Image Name: 2.2.13 for NFS on TQM850L
3181 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3182 Data Size: 381681 Bytes = 372 kB = 0 MB
3183 Load Address: 00000000
3184 Entry Point: 0000000c
3185 Verifying Checksum ... OK
3186 Uncompressing Kernel Image ... OK
3187 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
3188 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3189 time_init: decrementer frequency = 187500000/60
3190 Calibrating delay loop... 49.77 BogoMIPS
3191 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3194 If you want to boot a Linux kernel with initial ram disk, you pass
3195 the memory addresses of both the kernel and the initrd image (PPBCOOT
3196 format!) to the "bootm" command:
3198 => imi 40100000 40200000
3200 ## Checking Image at 40100000 ...
3201 Image Name: 2.2.13 for initrd on TQM850L
3202 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3203 Data Size: 335725 Bytes = 327 kB = 0 MB
3204 Load Address: 00000000
3205 Entry Point: 0000000c
3206 Verifying Checksum ... OK
3208 ## Checking Image at 40200000 ...
3209 Image Name: Simple Ramdisk Image
3210 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3211 Data Size: 566530 Bytes = 553 kB = 0 MB
3212 Load Address: 00000000
3213 Entry Point: 00000000
3214 Verifying Checksum ... OK
3216 => bootm 40100000 40200000
3217 ## Booting Linux kernel at 40100000 ...
3218 Image Name: 2.2.13 for initrd on TQM850L
3219 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3220 Data Size: 335725 Bytes = 327 kB = 0 MB
3221 Load Address: 00000000
3222 Entry Point: 0000000c
3223 Verifying Checksum ... OK
3224 Uncompressing Kernel Image ... OK
3225 ## Loading RAMDisk Image at 40200000 ...
3226 Image Name: Simple Ramdisk Image
3227 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3228 Data Size: 566530 Bytes = 553 kB = 0 MB
3229 Load Address: 00000000
3230 Entry Point: 00000000
3231 Verifying Checksum ... OK
3232 Loading Ramdisk ... OK
3233 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
3234 Boot arguments: root=/dev/ram
3235 time_init: decrementer frequency = 187500000/60
3236 Calibrating delay loop... 49.77 BogoMIPS
3238 RAMDISK: Compressed image found at block 0
3239 VFS: Mounted root (ext2 filesystem).
3243 Boot Linux and pass a flat device tree:
3246 First, U-Boot must be compiled with the appropriate defines. See the section
3247 titled "Linux Kernel Interface" above for a more in depth explanation. The
3248 following is an example of how to start a kernel and pass an updated
3254 oft=oftrees/mpc8540ads.dtb
3255 => tftp $oftaddr $oft
3256 Speed: 1000, full duplex
3258 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3259 Filename 'oftrees/mpc8540ads.dtb'.
3260 Load address: 0x300000
3263 Bytes transferred = 4106 (100a hex)
3264 => tftp $loadaddr $bootfile
3265 Speed: 1000, full duplex
3267 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3269 Load address: 0x200000
3270 Loading:############
3272 Bytes transferred = 1029407 (fb51f hex)
3277 => bootm $loadaddr - $oftaddr
3278 ## Booting image at 00200000 ...
3279 Image Name: Linux-2.6.17-dirty
3280 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3281 Data Size: 1029343 Bytes = 1005.2 kB
3282 Load Address: 00000000
3283 Entry Point: 00000000
3284 Verifying Checksum ... OK
3285 Uncompressing Kernel Image ... OK
3286 Booting using flat device tree at 0x300000
3287 Using MPC85xx ADS machine description
3288 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3292 More About U-Boot Image Types:
3293 ------------------------------
3295 U-Boot supports the following image types:
3297 "Standalone Programs" are directly runnable in the environment
3298 provided by U-Boot; it is expected that (if they behave
3299 well) you can continue to work in U-Boot after return from
3300 the Standalone Program.
3301 "OS Kernel Images" are usually images of some Embedded OS which
3302 will take over control completely. Usually these programs
3303 will install their own set of exception handlers, device
3304 drivers, set up the MMU, etc. - this means, that you cannot
3305 expect to re-enter U-Boot except by resetting the CPU.
3306 "RAMDisk Images" are more or less just data blocks, and their
3307 parameters (address, size) are passed to an OS kernel that is
3309 "Multi-File Images" contain several images, typically an OS
3310 (Linux) kernel image and one or more data images like
3311 RAMDisks. This construct is useful for instance when you want
3312 to boot over the network using BOOTP etc., where the boot
3313 server provides just a single image file, but you want to get
3314 for instance an OS kernel and a RAMDisk image.
3316 "Multi-File Images" start with a list of image sizes, each
3317 image size (in bytes) specified by an "uint32_t" in network
3318 byte order. This list is terminated by an "(uint32_t)0".
3319 Immediately after the terminating 0 follow the images, one by
3320 one, all aligned on "uint32_t" boundaries (size rounded up to
3321 a multiple of 4 bytes).
3323 "Firmware Images" are binary images containing firmware (like
3324 U-Boot or FPGA images) which usually will be programmed to
3327 "Script files" are command sequences that will be executed by
3328 U-Boot's command interpreter; this feature is especially
3329 useful when you configure U-Boot to use a real shell (hush)
3330 as command interpreter.
3336 One of the features of U-Boot is that you can dynamically load and
3337 run "standalone" applications, which can use some resources of
3338 U-Boot like console I/O functions or interrupt services.
3340 Two simple examples are included with the sources:
3345 'examples/hello_world.c' contains a small "Hello World" Demo
3346 application; it is automatically compiled when you build U-Boot.
3347 It's configured to run at address 0x00040004, so you can play with it
3351 ## Ready for S-Record download ...
3352 ~>examples/hello_world.srec
3353 1 2 3 4 5 6 7 8 9 10 11 ...
3354 [file transfer complete]
3356 ## Start Addr = 0x00040004
3358 => go 40004 Hello World! This is a test.
3359 ## Starting application at 0x00040004 ...
3370 Hit any key to exit ...
3372 ## Application terminated, rc = 0x0
3374 Another example, which demonstrates how to register a CPM interrupt
3375 handler with the U-Boot code, can be found in 'examples/timer.c'.
3376 Here, a CPM timer is set up to generate an interrupt every second.
3377 The interrupt service routine is trivial, just printing a '.'
3378 character, but this is just a demo program. The application can be
3379 controlled by the following keys:
3381 ? - print current values og the CPM Timer registers
3382 b - enable interrupts and start timer
3383 e - stop timer and disable interrupts
3384 q - quit application
3387 ## Ready for S-Record download ...
3388 ~>examples/timer.srec
3389 1 2 3 4 5 6 7 8 9 10 11 ...
3390 [file transfer complete]
3392 ## Start Addr = 0x00040004
3395 ## Starting application at 0x00040004 ...
3398 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3401 [q, b, e, ?] Set interval 1000000 us
3404 [q, b, e, ?] ........
3405 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3408 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3411 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3414 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3416 [q, b, e, ?] ...Stopping timer
3418 [q, b, e, ?] ## Application terminated, rc = 0x0
3424 Over time, many people have reported problems when trying to use the
3425 "minicom" terminal emulation program for serial download. I (wd)
3426 consider minicom to be broken, and recommend not to use it. Under
3427 Unix, I recommend to use C-Kermit for general purpose use (and
3428 especially for kermit binary protocol download ("loadb" command), and
3429 use "cu" for S-Record download ("loads" command).
3431 Nevertheless, if you absolutely want to use it try adding this
3432 configuration to your "File transfer protocols" section:
3434 Name Program Name U/D FullScr IO-Red. Multi
3435 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3436 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3442 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3443 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3445 Building requires a cross environment; it is known to work on
3446 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3447 need gmake since the Makefiles are not compatible with BSD make).
3448 Note that the cross-powerpc package does not install include files;
3449 attempting to build U-Boot will fail because <machine/ansi.h> is
3450 missing. This file has to be installed and patched manually:
3452 # cd /usr/pkg/cross/powerpc-netbsd/include
3454 # ln -s powerpc machine
3455 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3456 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3458 Native builds *don't* work due to incompatibilities between native
3459 and U-Boot include files.
3461 Booting assumes that (the first part of) the image booted is a
3462 stage-2 loader which in turn loads and then invokes the kernel
3463 proper. Loader sources will eventually appear in the NetBSD source
3464 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3465 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3468 Implementation Internals:
3469 =========================
3471 The following is not intended to be a complete description of every
3472 implementation detail. However, it should help to understand the
3473 inner workings of U-Boot and make it easier to port it to custom
3477 Initial Stack, Global Data:
3478 ---------------------------
3480 The implementation of U-Boot is complicated by the fact that U-Boot
3481 starts running out of ROM (flash memory), usually without access to
3482 system RAM (because the memory controller is not initialized yet).
3483 This means that we don't have writable Data or BSS segments, and BSS
3484 is not initialized as zero. To be able to get a C environment working
3485 at all, we have to allocate at least a minimal stack. Implementation
3486 options for this are defined and restricted by the CPU used: Some CPU
3487 models provide on-chip memory (like the IMMR area on MPC8xx and
3488 MPC826x processors), on others (parts of) the data cache can be
3489 locked as (mis-) used as memory, etc.
3491 Chris Hallinan posted a good summary of these issues to the
3492 u-boot-users mailing list:
3494 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3495 From: "Chris Hallinan" <clh@net1plus.com>
3496 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3499 Correct me if I'm wrong, folks, but the way I understand it
3500 is this: Using DCACHE as initial RAM for Stack, etc, does not
3501 require any physical RAM backing up the cache. The cleverness
3502 is that the cache is being used as a temporary supply of
3503 necessary storage before the SDRAM controller is setup. It's
3504 beyond the scope of this list to expain the details, but you
3505 can see how this works by studying the cache architecture and
3506 operation in the architecture and processor-specific manuals.
3508 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3509 is another option for the system designer to use as an
3510 initial stack/ram area prior to SDRAM being available. Either
3511 option should work for you. Using CS 4 should be fine if your
3512 board designers haven't used it for something that would
3513 cause you grief during the initial boot! It is frequently not
3516 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3517 with your processor/board/system design. The default value
3518 you will find in any recent u-boot distribution in
3519 walnut.h should work for you. I'd set it to a value larger
3520 than your SDRAM module. If you have a 64MB SDRAM module, set
3521 it above 400_0000. Just make sure your board has no resources
3522 that are supposed to respond to that address! That code in
3523 start.S has been around a while and should work as is when
3524 you get the config right.
3529 It is essential to remember this, since it has some impact on the C
3530 code for the initialization procedures:
3532 * Initialized global data (data segment) is read-only. Do not attempt
3535 * Do not use any unitialized global data (or implicitely initialized
3536 as zero data - BSS segment) at all - this is undefined, initiali-
3537 zation is performed later (when relocating to RAM).
3539 * Stack space is very limited. Avoid big data buffers or things like
3542 Having only the stack as writable memory limits means we cannot use
3543 normal global data to share information beween the code. But it
3544 turned out that the implementation of U-Boot can be greatly
3545 simplified by making a global data structure (gd_t) available to all
3546 functions. We could pass a pointer to this data as argument to _all_
3547 functions, but this would bloat the code. Instead we use a feature of
3548 the GCC compiler (Global Register Variables) to share the data: we
3549 place a pointer (gd) to the global data into a register which we
3550 reserve for this purpose.
3552 When choosing a register for such a purpose we are restricted by the
3553 relevant (E)ABI specifications for the current architecture, and by
3554 GCC's implementation.
3556 For PowerPC, the following registers have specific use:
3558 R2: reserved for system use
3559 R3-R4: parameter passing and return values
3560 R5-R10: parameter passing
3561 R13: small data area pointer
3565 (U-Boot also uses R14 as internal GOT pointer.)
3567 ==> U-Boot will use R2 to hold a pointer to the global data
3569 Note: on PPC, we could use a static initializer (since the
3570 address of the global data structure is known at compile time),
3571 but it turned out that reserving a register results in somewhat
3572 smaller code - although the code savings are not that big (on
3573 average for all boards 752 bytes for the whole U-Boot image,
3574 624 text + 127 data).
3576 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3577 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3579 ==> U-Boot will use P5 to hold a pointer to the global data
3581 On ARM, the following registers are used:
3583 R0: function argument word/integer result
3584 R1-R3: function argument word
3586 R10: stack limit (used only if stack checking if enabled)
3587 R11: argument (frame) pointer
3588 R12: temporary workspace
3591 R15: program counter
3593 ==> U-Boot will use R8 to hold a pointer to the global data
3595 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3596 or current versions of GCC may "optimize" the code too much.
3601 U-Boot runs in system state and uses physical addresses, i.e. the
3602 MMU is not used either for address mapping nor for memory protection.
3604 The available memory is mapped to fixed addresses using the memory
3605 controller. In this process, a contiguous block is formed for each
3606 memory type (Flash, SDRAM, SRAM), even when it consists of several
3607 physical memory banks.
3609 U-Boot is installed in the first 128 kB of the first Flash bank (on
3610 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3611 booting and sizing and initializing DRAM, the code relocates itself
3612 to the upper end of DRAM. Immediately below the U-Boot code some
3613 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3614 configuration setting]. Below that, a structure with global Board
3615 Info data is placed, followed by the stack (growing downward).
3617 Additionally, some exception handler code is copied to the low 8 kB
3618 of DRAM (0x00000000 ... 0x00001FFF).
3620 So a typical memory configuration with 16 MB of DRAM could look like
3623 0x0000 0000 Exception Vector code
3626 0x0000 2000 Free for Application Use
3632 0x00FB FF20 Monitor Stack (Growing downward)
3633 0x00FB FFAC Board Info Data and permanent copy of global data
3634 0x00FC 0000 Malloc Arena
3637 0x00FE 0000 RAM Copy of Monitor Code
3638 ... eventually: LCD or video framebuffer
3639 ... eventually: pRAM (Protected RAM - unchanged by reset)
3640 0x00FF FFFF [End of RAM]
3643 System Initialization:
3644 ----------------------
3646 In the reset configuration, U-Boot starts at the reset entry point
3647 (on most PowerPC systens at address 0x00000100). Because of the reset
3648 configuration for CS0# this is a mirror of the onboard Flash memory.
3649 To be able to re-map memory U-Boot then jumps to its link address.
3650 To be able to implement the initialization code in C, a (small!)
3651 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3652 which provide such a feature like MPC8xx or MPC8260), or in a locked
3653 part of the data cache. After that, U-Boot initializes the CPU core,
3654 the caches and the SIU.
3656 Next, all (potentially) available memory banks are mapped using a
3657 preliminary mapping. For example, we put them on 512 MB boundaries
3658 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3659 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3660 programmed for SDRAM access. Using the temporary configuration, a
3661 simple memory test is run that determines the size of the SDRAM
3664 When there is more than one SDRAM bank, and the banks are of
3665 different size, the largest is mapped first. For equal size, the first
3666 bank (CS2#) is mapped first. The first mapping is always for address
3667 0x00000000, with any additional banks following immediately to create
3668 contiguous memory starting from 0.
3670 Then, the monitor installs itself at the upper end of the SDRAM area
3671 and allocates memory for use by malloc() and for the global Board
3672 Info data; also, the exception vector code is copied to the low RAM
3673 pages, and the final stack is set up.
3675 Only after this relocation will you have a "normal" C environment;
3676 until that you are restricted in several ways, mostly because you are
3677 running from ROM, and because the code will have to be relocated to a
3681 U-Boot Porting Guide:
3682 ----------------------
3684 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3688 int main (int argc, char *argv[])
3690 sighandler_t no_more_time;
3692 signal (SIGALRM, no_more_time);
3693 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3695 if (available_money > available_manpower) {
3696 pay consultant to port U-Boot;
3700 Download latest U-Boot source;
3702 Subscribe to u-boot-users mailing list;
3705 email ("Hi, I am new to U-Boot, how do I get started?");
3709 Read the README file in the top level directory;
3710 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3711 Read the source, Luke;
3714 if (available_money > toLocalCurrency ($2500)) {
3717 Add a lot of aggravation and time;
3720 Create your own board support subdirectory;
3722 Create your own board config file;
3726 Add / modify source code;
3730 email ("Hi, I am having problems...");
3732 Send patch file to Wolfgang;
3737 void no_more_time (int sig)
3746 All contributions to U-Boot should conform to the Linux kernel
3747 coding style; see the file "Documentation/CodingStyle" and the script
3748 "scripts/Lindent" in your Linux kernel source directory. In sources
3749 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3750 spaces before parameters to function calls) is actually used.
3752 Source files originating from a different project (for example the
3753 MTD subsystem) are generally exempt from these guidelines and are not
3754 reformated to ease subsequent migration to newer versions of those
3757 Please note that U-Boot is implemented in C (and to some small parts in
3758 Assembler); no C++ is used, so please do not use C++ style comments (//)
3761 Please also stick to the following formatting rules:
3762 - remove any trailing white space
3763 - use TAB characters for indentation, not spaces
3764 - make sure NOT to use DOS '\r\n' line feeds
3765 - do not add more than 2 empty lines to source files
3766 - do not add trailing empty lines to source files
3768 Submissions which do not conform to the standards may be returned
3769 with a request to reformat the changes.
3775 Since the number of patches for U-Boot is growing, we need to
3776 establish some rules. Submissions which do not conform to these rules
3777 may be rejected, even when they contain important and valuable stuff.
3779 Patches shall be sent to the u-boot-users mailing list.
3781 When you send a patch, please include the following information with
3784 * For bug fixes: a description of the bug and how your patch fixes
3785 this bug. Please try to include a way of demonstrating that the
3786 patch actually fixes something.
3788 * For new features: a description of the feature and your
3791 * A CHANGELOG entry as plaintext (separate from the patch)
3793 * For major contributions, your entry to the CREDITS file
3795 * When you add support for a new board, don't forget to add this
3796 board to the MAKEALL script, too.
3798 * If your patch adds new configuration options, don't forget to
3799 document these in the README file.
3801 * The patch itself. If you are accessing the CVS repository use "cvs
3802 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3803 version of diff does not support these options, then get the latest
3804 version of GNU diff.
3806 The current directory when running this command shall be the top
3807 level directory of the U-Boot source tree, or it's parent directory
3808 (i. e. please make sure that your patch includes sufficient
3809 directory information for the affected files).
3811 We accept patches as plain text, MIME attachments or as uuencoded
3814 * If one logical set of modifications affects or creates several
3815 files, all these changes shall be submitted in a SINGLE patch file.
3817 * Changesets that contain different, unrelated modifications shall be
3818 submitted as SEPARATE patches, one patch per changeset.
3823 * Before sending the patch, run the MAKEALL script on your patched
3824 source tree and make sure that no errors or warnings are reported
3825 for any of the boards.
3827 * Keep your modifications to the necessary minimum: A patch
3828 containing several unrelated changes or arbitrary reformats will be
3829 returned with a request to re-formatting / split it.
3831 * If you modify existing code, make sure that your new code does not
3832 add to the memory footprint of the code ;-) Small is beautiful!
3833 When adding new features, these should compile conditionally only
3834 (using #ifdef), and the resulting code with the new feature
3835 disabled must not need more memory than the old code without your
3838 * Remember that there is a size limit of 40 kB per message on the
3839 u-boot-users mailing list. Compression may help.
projects / u-boot / blob