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_ISL1208 - use Intersil ISL1208 RTC
673 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
675 Note that if the RTC uses I2C, then the I2C interface
676 must also be configured. See I2C Support, below.
680 When CONFIG_TIMESTAMP is selected, the timestamp
681 (date and time) of an image is printed by image
682 commands like bootm or iminfo. This option is
683 automatically enabled when you select CONFIG_CMD_DATE .
686 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
687 and/or CONFIG_ISO_PARTITION
689 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
690 CONFIG_CMD_SCSI) you must configure support for at least
691 one partition type as well.
694 CONFIG_IDE_RESET_ROUTINE - this is defined in several
695 board configurations files but used nowhere!
697 CONFIG_IDE_RESET - is this is defined, IDE Reset will
698 be performed by calling the function
699 ide_set_reset(int reset)
700 which has to be defined in a board specific file
705 Set this to enable ATAPI support.
710 Set this to enable support for disks larger than 137GB
711 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
712 Whithout these , LBA48 support uses 32bit variables and will 'only'
713 support disks up to 2.1TB.
716 When enabled, makes the IDE subsystem use 64bit sector addresses.
720 At the moment only there is only support for the
721 SYM53C8XX SCSI controller; define
722 CONFIG_SCSI_SYM53C8XX to enable it.
724 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
725 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
726 CFG_SCSI_MAX_LUN] can be adjusted to define the
727 maximum numbers of LUNs, SCSI ID's and target
729 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
731 - NETWORK Support (PCI):
733 Support for Intel 8254x gigabit chips.
736 Support for Intel 82557/82559/82559ER chips.
737 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
738 write routine for first time initialisation.
741 Support for Digital 2114x chips.
742 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
743 modem chip initialisation (KS8761/QS6611).
746 Support for National dp83815 chips.
749 Support for National dp8382[01] gigabit chips.
751 - NETWORK Support (other):
753 CONFIG_DRIVER_LAN91C96
754 Support for SMSC's LAN91C96 chips.
757 Define this to hold the physical address
758 of the LAN91C96's I/O space
760 CONFIG_LAN91C96_USE_32_BIT
761 Define this to enable 32 bit addressing
763 CONFIG_DRIVER_SMC91111
764 Support for SMSC's LAN91C111 chip
767 Define this to hold the physical address
768 of the device (I/O space)
770 CONFIG_SMC_USE_32_BIT
771 Define this if data bus is 32 bits
773 CONFIG_SMC_USE_IOFUNCS
774 Define this to use i/o functions instead of macros
775 (some hardware wont work with macros)
778 At the moment only the UHCI host controller is
779 supported (PIP405, MIP405, MPC5200); define
780 CONFIG_USB_UHCI to enable it.
781 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
782 and define CONFIG_USB_STORAGE to enable the USB
785 Supported are USB Keyboards and USB Floppy drives
787 MPC5200 USB requires additional defines:
789 for 528 MHz Clock: 0x0001bbbb
791 for differential drivers: 0x00001000
792 for single ended drivers: 0x00005000
794 May be defined to allow interrupt polling
795 instead of using asynchronous interrupts
798 Define the below if you wish to use the USB console.
799 Once firmware is rebuilt from a serial console issue the
800 command "setenv stdin usbtty; setenv stdout usbtty" and
801 attach your usb cable. The Unix command "dmesg" should print
802 it has found a new device. The environment variable usbtty
803 can be set to gserial or cdc_acm to enable your device to
804 appear to a USB host as a Linux gserial device or a
805 Common Device Class Abstract Control Model serial device.
806 If you select usbtty = gserial you should be able to enumerate
808 # modprobe usbserial vendor=0xVendorID product=0xProductID
809 else if using cdc_acm, simply setting the environment
810 variable usbtty to be cdc_acm should suffice. The following
811 might be defined in YourBoardName.h
814 Define this to build a UDC device
817 Define this to have a tty type of device available to
818 talk to the UDC device
820 CFG_CONSOLE_IS_IN_ENV
821 Define this if you want stdin, stdout &/or stderr to
825 CFG_USB_EXTC_CLK 0xBLAH
826 Derive USB clock from external clock "blah"
827 - CFG_USB_EXTC_CLK 0x02
829 CFG_USB_BRG_CLK 0xBLAH
830 Derive USB clock from brgclk
831 - CFG_USB_BRG_CLK 0x04
833 If you have a USB-IF assigned VendorID then you may wish to
834 define your own vendor specific values either in BoardName.h
835 or directly in usbd_vendor_info.h. If you don't define
836 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
837 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
838 should pretend to be a Linux device to it's target host.
840 CONFIG_USBD_MANUFACTURER
841 Define this string as the name of your company for
842 - CONFIG_USBD_MANUFACTURER "my company"
844 CONFIG_USBD_PRODUCT_NAME
845 Define this string as the name of your product
846 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
849 Define this as your assigned Vendor ID from the USB
850 Implementors Forum. This *must* be a genuine Vendor ID
851 to avoid polluting the USB namespace.
852 - CONFIG_USBD_VENDORID 0xFFFF
854 CONFIG_USBD_PRODUCTID
855 Define this as the unique Product ID
857 - CONFIG_USBD_PRODUCTID 0xFFFF
861 The MMC controller on the Intel PXA is supported. To
862 enable this define CONFIG_MMC. The MMC can be
863 accessed from the boot prompt by mapping the device
864 to physical memory similar to flash. Command line is
865 enabled with CONFIG_CMD_MMC. The MMC driver also works with
866 the FAT fs. This is enabled with CONFIG_CMD_FAT.
868 - Journaling Flash filesystem support:
869 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
870 CONFIG_JFFS2_NAND_DEV
871 Define these for a default partition on a NAND device
873 CFG_JFFS2_FIRST_SECTOR,
874 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
875 Define these for a default partition on a NOR device
878 Define this to create an own partition. You have to provide a
879 function struct part_info* jffs2_part_info(int part_num)
881 If you define only one JFFS2 partition you may also want to
882 #define CFG_JFFS_SINGLE_PART 1
883 to disable the command chpart. This is the default when you
884 have not defined a custom partition
889 Define this to enable standard (PC-Style) keyboard
893 Standard PC keyboard driver with US (is default) and
894 GERMAN key layout (switch via environment 'keymap=de') support.
895 Export function i8042_kbd_init, i8042_tstc and i8042_getc
896 for cfb_console. Supports cursor blinking.
901 Define this to enable video support (for output to
906 Enable Chips & Technologies 69000 Video chip
908 CONFIG_VIDEO_SMI_LYNXEM
909 Enable Silicon Motion SMI 712/710/810 Video chip. The
910 video output is selected via environment 'videoout'
911 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
914 For the CT69000 and SMI_LYNXEM drivers, videomode is
915 selected via environment 'videomode'. Two diferent ways
917 - "videomode=num" 'num' is a standard LiLo mode numbers.
918 Following standard modes are supported (* is default):
920 Colors 640x480 800x600 1024x768 1152x864 1280x1024
921 -------------+---------------------------------------------
922 8 bits | 0x301* 0x303 0x305 0x161 0x307
923 15 bits | 0x310 0x313 0x316 0x162 0x319
924 16 bits | 0x311 0x314 0x317 0x163 0x31A
925 24 bits | 0x312 0x315 0x318 ? 0x31B
926 -------------+---------------------------------------------
927 (i.e. setenv videomode 317; saveenv; reset;)
929 - "videomode=bootargs" all the video parameters are parsed
930 from the bootargs. (See drivers/video/videomodes.c)
933 CONFIG_VIDEO_SED13806
934 Enable Epson SED13806 driver. This driver supports 8bpp
935 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
936 or CONFIG_VIDEO_SED13806_16BPP
941 Define this to enable a custom keyboard support.
942 This simply calls drv_keyboard_init() which must be
943 defined in your board-specific files.
944 The only board using this so far is RBC823.
946 - LCD Support: CONFIG_LCD
948 Define this to enable LCD support (for output to LCD
949 display); also select one of the supported displays
950 by defining one of these:
952 CONFIG_NEC_NL6448AC33:
954 NEC NL6448AC33-18. Active, color, single scan.
956 CONFIG_NEC_NL6448BC20
958 NEC NL6448BC20-08. 6.5", 640x480.
959 Active, color, single scan.
961 CONFIG_NEC_NL6448BC33_54
963 NEC NL6448BC33-54. 10.4", 640x480.
964 Active, color, single scan.
968 Sharp 320x240. Active, color, single scan.
969 It isn't 16x9, and I am not sure what it is.
971 CONFIG_SHARP_LQ64D341
973 Sharp LQ64D341 display, 640x480.
974 Active, color, single scan.
978 HLD1045 display, 640x480.
979 Active, color, single scan.
983 Optrex CBL50840-2 NF-FW 99 22 M5
985 Hitachi LMG6912RPFC-00T
989 320x240. Black & white.
991 Normally display is black on white background; define
992 CFG_WHITE_ON_BLACK to get it inverted.
994 - Splash Screen Support: CONFIG_SPLASH_SCREEN
996 If this option is set, the environment is checked for
997 a variable "splashimage". If found, the usual display
998 of logo, copyright and system information on the LCD
999 is suppressed and the BMP image at the address
1000 specified in "splashimage" is loaded instead. The
1001 console is redirected to the "nulldev", too. This
1002 allows for a "silent" boot where a splash screen is
1003 loaded very quickly after power-on.
1005 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1007 If this option is set, additionally to standard BMP
1008 images, gzipped BMP images can be displayed via the
1009 splashscreen support or the bmp command.
1011 - Compression support:
1014 If this option is set, support for bzip2 compressed
1015 images is included. If not, only uncompressed and gzip
1016 compressed images are supported.
1018 NOTE: the bzip2 algorithm requires a lot of RAM, so
1019 the malloc area (as defined by CFG_MALLOC_LEN) should
1025 The address of PHY on MII bus.
1027 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1029 The clock frequency of the MII bus
1033 If this option is set, support for speed/duplex
1034 detection of Gigabit PHY is included.
1036 CONFIG_PHY_RESET_DELAY
1038 Some PHY like Intel LXT971A need extra delay after
1039 reset before any MII register access is possible.
1040 For such PHY, set this option to the usec delay
1041 required. (minimum 300usec for LXT971A)
1043 CONFIG_PHY_CMD_DELAY (ppc4xx)
1045 Some PHY like Intel LXT971A need extra delay after
1046 command issued before MII status register can be read
1053 Define a default value for ethernet address to use
1054 for the respective ethernet interface, in case this
1055 is not determined automatically.
1060 Define a default value for the IP address to use for
1061 the default ethernet interface, in case this is not
1062 determined through e.g. bootp.
1064 - Server IP address:
1067 Defines a default value for theIP address of a TFTP
1068 server to contact when using the "tftboot" command.
1070 - Multicast TFTP Mode:
1073 Defines whether you want to support multicast TFTP as per
1074 rfc-2090; for example to work with atftp. Lets lots of targets
1075 tftp down the same boot image concurrently. Note: the ethernet
1076 driver in use must provide a function: mcast() to join/leave a
1079 CONFIG_BOOTP_RANDOM_DELAY
1080 - BOOTP Recovery Mode:
1081 CONFIG_BOOTP_RANDOM_DELAY
1083 If you have many targets in a network that try to
1084 boot using BOOTP, you may want to avoid that all
1085 systems send out BOOTP requests at precisely the same
1086 moment (which would happen for instance at recovery
1087 from a power failure, when all systems will try to
1088 boot, thus flooding the BOOTP server. Defining
1089 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1090 inserted before sending out BOOTP requests. The
1091 following delays are inserted then:
1093 1st BOOTP request: delay 0 ... 1 sec
1094 2nd BOOTP request: delay 0 ... 2 sec
1095 3rd BOOTP request: delay 0 ... 4 sec
1097 BOOTP requests: delay 0 ... 8 sec
1099 - DHCP Advanced Options:
1100 You can fine tune the DHCP functionality by defining
1101 CONFIG_BOOTP_* symbols:
1103 CONFIG_BOOTP_SUBNETMASK
1104 CONFIG_BOOTP_GATEWAY
1105 CONFIG_BOOTP_HOSTNAME
1106 CONFIG_BOOTP_NISDOMAIN
1107 CONFIG_BOOTP_BOOTPATH
1108 CONFIG_BOOTP_BOOTFILESIZE
1111 CONFIG_BOOTP_SEND_HOSTNAME
1112 CONFIG_BOOTP_NTPSERVER
1113 CONFIG_BOOTP_TIMEOFFSET
1114 CONFIG_BOOTP_VENDOREX
1116 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1117 environment variable, not the BOOTP server.
1119 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1120 serverip from a DHCP server, it is possible that more
1121 than one DNS serverip is offered to the client.
1122 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1123 serverip will be stored in the additional environment
1124 variable "dnsip2". The first DNS serverip is always
1125 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1128 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1129 to do a dynamic update of a DNS server. To do this, they
1130 need the hostname of the DHCP requester.
1131 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1132 of the "hostname" environment variable is passed as
1133 option 12 to the DHCP server.
1136 CONFIG_CDP_DEVICE_ID
1138 The device id used in CDP trigger frames.
1140 CONFIG_CDP_DEVICE_ID_PREFIX
1142 A two character string which is prefixed to the MAC address
1147 A printf format string which contains the ascii name of
1148 the port. Normally is set to "eth%d" which sets
1149 eth0 for the first ethernet, eth1 for the second etc.
1151 CONFIG_CDP_CAPABILITIES
1153 A 32bit integer which indicates the device capabilities;
1154 0x00000010 for a normal host which does not forwards.
1158 An ascii string containing the version of the software.
1162 An ascii string containing the name of the platform.
1166 A 32bit integer sent on the trigger.
1168 CONFIG_CDP_POWER_CONSUMPTION
1170 A 16bit integer containing the power consumption of the
1171 device in .1 of milliwatts.
1173 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1175 A byte containing the id of the VLAN.
1177 - Status LED: CONFIG_STATUS_LED
1179 Several configurations allow to display the current
1180 status using a LED. For instance, the LED will blink
1181 fast while running U-Boot code, stop blinking as
1182 soon as a reply to a BOOTP request was received, and
1183 start blinking slow once the Linux kernel is running
1184 (supported by a status LED driver in the Linux
1185 kernel). Defining CONFIG_STATUS_LED enables this
1188 - CAN Support: CONFIG_CAN_DRIVER
1190 Defining CONFIG_CAN_DRIVER enables CAN driver support
1191 on those systems that support this (optional)
1192 feature, like the TQM8xxL modules.
1194 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1196 These enable I2C serial bus commands. Defining either of
1197 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1198 include the appropriate I2C driver for the selected cpu.
1200 This will allow you to use i2c commands at the u-boot
1201 command line (as long as you set CONFIG_CMD_I2C in
1202 CONFIG_COMMANDS) and communicate with i2c based realtime
1203 clock chips. See common/cmd_i2c.c for a description of the
1204 command line interface.
1206 CONFIG_I2C_CMD_TREE is a recommended option that places
1207 all I2C commands under a single 'i2c' root command. The
1208 older 'imm', 'imd', 'iprobe' etc. commands are considered
1209 deprecated and may disappear in the future.
1211 CONFIG_HARD_I2C selects a hardware I2C controller.
1213 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1214 bit-banging) driver instead of CPM or similar hardware
1217 There are several other quantities that must also be
1218 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1220 In both cases you will need to define CFG_I2C_SPEED
1221 to be the frequency (in Hz) at which you wish your i2c bus
1222 to run and CFG_I2C_SLAVE to be the address of this node (ie
1223 the cpu's i2c node address).
1225 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1226 sets the cpu up as a master node and so its address should
1227 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1228 p.16-473). So, set CFG_I2C_SLAVE to 0.
1230 That's all that's required for CONFIG_HARD_I2C.
1232 If you use the software i2c interface (CONFIG_SOFT_I2C)
1233 then the following macros need to be defined (examples are
1234 from include/configs/lwmon.h):
1238 (Optional). Any commands necessary to enable the I2C
1239 controller or configure ports.
1241 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1245 (Only for MPC8260 CPU). The I/O port to use (the code
1246 assumes both bits are on the same port). Valid values
1247 are 0..3 for ports A..D.
1251 The code necessary to make the I2C data line active
1252 (driven). If the data line is open collector, this
1255 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1259 The code necessary to make the I2C data line tri-stated
1260 (inactive). If the data line is open collector, this
1263 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1267 Code that returns TRUE if the I2C data line is high,
1270 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1274 If <bit> is TRUE, sets the I2C data line high. If it
1275 is FALSE, it clears it (low).
1277 eg: #define I2C_SDA(bit) \
1278 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1279 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1283 If <bit> is TRUE, sets the I2C clock line high. If it
1284 is FALSE, it clears it (low).
1286 eg: #define I2C_SCL(bit) \
1287 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1288 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1292 This delay is invoked four times per clock cycle so this
1293 controls the rate of data transfer. The data rate thus
1294 is 1 / (I2C_DELAY * 4). Often defined to be something
1297 #define I2C_DELAY udelay(2)
1301 When a board is reset during an i2c bus transfer
1302 chips might think that the current transfer is still
1303 in progress. On some boards it is possible to access
1304 the i2c SCLK line directly, either by using the
1305 processor pin as a GPIO or by having a second pin
1306 connected to the bus. If this option is defined a
1307 custom i2c_init_board() routine in boards/xxx/board.c
1308 is run early in the boot sequence.
1310 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1312 This option enables configuration of bi_iic_fast[] flags
1313 in u-boot bd_info structure based on u-boot environment
1314 variable "i2cfast". (see also i2cfast)
1316 CONFIG_I2C_MULTI_BUS
1318 This option allows the use of multiple I2C buses, each of which
1319 must have a controller. At any point in time, only one bus is
1320 active. To switch to a different bus, use the 'i2c dev' command.
1321 Note that bus numbering is zero-based.
1325 This option specifies a list of I2C devices that will be skipped
1326 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1327 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1328 pairs. Otherwise, specify a 1D array of device addresses
1331 #undef CONFIG_I2C_MULTI_BUS
1332 #define CFG_I2C_NOPROBES {0x50,0x68}
1334 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1336 #define CONFIG_I2C_MULTI_BUS
1337 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1339 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1343 If defined, then this indicates the I2C bus number for DDR SPD.
1344 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1348 If defined, then this indicates the I2C bus number for the RTC.
1349 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1353 If defined, then this indicates the I2C bus number for the DTT.
1354 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1358 Define this option if you want to use Freescale's I2C driver in
1359 drivers/i2c/fsl_i2c.c.
1362 - SPI Support: CONFIG_SPI
1364 Enables SPI driver (so far only tested with
1365 SPI EEPROM, also an instance works with Crystal A/D and
1366 D/As on the SACSng board)
1370 Enables extended (16-bit) SPI EEPROM addressing.
1371 (symmetrical to CONFIG_I2C_X)
1375 Enables a software (bit-bang) SPI driver rather than
1376 using hardware support. This is a general purpose
1377 driver that only requires three general I/O port pins
1378 (two outputs, one input) to function. If this is
1379 defined, the board configuration must define several
1380 SPI configuration items (port pins to use, etc). For
1381 an example, see include/configs/sacsng.h.
1385 Enables a hardware SPI driver for general-purpose reads
1386 and writes. As with CONFIG_SOFT_SPI, the board configuration
1387 must define a list of chip-select function pointers.
1388 Currently supported on some MPC8xxx processors. For an
1389 example, see include/configs/mpc8349emds.h.
1391 - FPGA Support: CONFIG_FPGA
1393 Enables FPGA subsystem.
1395 CONFIG_FPGA_<vendor>
1397 Enables support for specific chip vendors.
1400 CONFIG_FPGA_<family>
1402 Enables support for FPGA family.
1403 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1407 Specify the number of FPGA devices to support.
1409 CFG_FPGA_PROG_FEEDBACK
1411 Enable printing of hash marks during FPGA configuration.
1415 Enable checks on FPGA configuration interface busy
1416 status by the configuration function. This option
1417 will require a board or device specific function to
1422 If defined, a function that provides delays in the FPGA
1423 configuration driver.
1425 CFG_FPGA_CHECK_CTRLC
1426 Allow Control-C to interrupt FPGA configuration
1428 CFG_FPGA_CHECK_ERROR
1430 Check for configuration errors during FPGA bitfile
1431 loading. For example, abort during Virtex II
1432 configuration if the INIT_B line goes low (which
1433 indicated a CRC error).
1437 Maximum time to wait for the INIT_B line to deassert
1438 after PROB_B has been deasserted during a Virtex II
1439 FPGA configuration sequence. The default time is 500
1444 Maximum time to wait for BUSY to deassert during
1445 Virtex II FPGA configuration. The default is 5 mS.
1447 CFG_FPGA_WAIT_CONFIG
1449 Time to wait after FPGA configuration. The default is
1452 - Configuration Management:
1455 If defined, this string will be added to the U-Boot
1456 version information (U_BOOT_VERSION)
1458 - Vendor Parameter Protection:
1460 U-Boot considers the values of the environment
1461 variables "serial#" (Board Serial Number) and
1462 "ethaddr" (Ethernet Address) to be parameters that
1463 are set once by the board vendor / manufacturer, and
1464 protects these variables from casual modification by
1465 the user. Once set, these variables are read-only,
1466 and write or delete attempts are rejected. You can
1467 change this behviour:
1469 If CONFIG_ENV_OVERWRITE is #defined in your config
1470 file, the write protection for vendor parameters is
1471 completely disabled. Anybody can change or delete
1474 Alternatively, if you #define _both_ CONFIG_ETHADDR
1475 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1476 ethernet address is installed in the environment,
1477 which can be changed exactly ONCE by the user. [The
1478 serial# is unaffected by this, i. e. it remains
1484 Define this variable to enable the reservation of
1485 "protected RAM", i. e. RAM which is not overwritten
1486 by U-Boot. Define CONFIG_PRAM to hold the number of
1487 kB you want to reserve for pRAM. You can overwrite
1488 this default value by defining an environment
1489 variable "pram" to the number of kB you want to
1490 reserve. Note that the board info structure will
1491 still show the full amount of RAM. If pRAM is
1492 reserved, a new environment variable "mem" will
1493 automatically be defined to hold the amount of
1494 remaining RAM in a form that can be passed as boot
1495 argument to Linux, for instance like that:
1497 setenv bootargs ... mem=\${mem}
1500 This way you can tell Linux not to use this memory,
1501 either, which results in a memory region that will
1502 not be affected by reboots.
1504 *WARNING* If your board configuration uses automatic
1505 detection of the RAM size, you must make sure that
1506 this memory test is non-destructive. So far, the
1507 following board configurations are known to be
1510 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1511 HERMES, IP860, RPXlite, LWMON, LANTEC,
1512 PCU_E, FLAGADM, TQM8260
1517 Define this variable to stop the system in case of a
1518 fatal error, so that you have to reset it manually.
1519 This is probably NOT a good idea for an embedded
1520 system where you want to system to reboot
1521 automatically as fast as possible, but it may be
1522 useful during development since you can try to debug
1523 the conditions that lead to the situation.
1525 CONFIG_NET_RETRY_COUNT
1527 This variable defines the number of retries for
1528 network operations like ARP, RARP, TFTP, or BOOTP
1529 before giving up the operation. If not defined, a
1530 default value of 5 is used.
1532 - Command Interpreter:
1533 CONFIG_AUTO_COMPLETE
1535 Enable auto completion of commands using TAB.
1537 Note that this feature has NOT been implemented yet
1538 for the "hush" shell.
1543 Define this variable to enable the "hush" shell (from
1544 Busybox) as command line interpreter, thus enabling
1545 powerful command line syntax like
1546 if...then...else...fi conditionals or `&&' and '||'
1547 constructs ("shell scripts").
1549 If undefined, you get the old, much simpler behaviour
1550 with a somewhat smaller memory footprint.
1555 This defines the secondary prompt string, which is
1556 printed when the command interpreter needs more input
1557 to complete a command. Usually "> ".
1561 In the current implementation, the local variables
1562 space and global environment variables space are
1563 separated. Local variables are those you define by
1564 simply typing `name=value'. To access a local
1565 variable later on, you have write `$name' or
1566 `${name}'; to execute the contents of a variable
1567 directly type `$name' at the command prompt.
1569 Global environment variables are those you use
1570 setenv/printenv to work with. To run a command stored
1571 in such a variable, you need to use the run command,
1572 and you must not use the '$' sign to access them.
1574 To store commands and special characters in a
1575 variable, please use double quotation marks
1576 surrounding the whole text of the variable, instead
1577 of the backslashes before semicolons and special
1580 - Commandline Editing and History:
1581 CONFIG_CMDLINE_EDITING
1583 Enable editiong and History functions for interactive
1584 commandline input operations
1586 - Default Environment:
1587 CONFIG_EXTRA_ENV_SETTINGS
1589 Define this to contain any number of null terminated
1590 strings (variable = value pairs) that will be part of
1591 the default environment compiled into the boot image.
1593 For example, place something like this in your
1594 board's config file:
1596 #define CONFIG_EXTRA_ENV_SETTINGS \
1600 Warning: This method is based on knowledge about the
1601 internal format how the environment is stored by the
1602 U-Boot code. This is NOT an official, exported
1603 interface! Although it is unlikely that this format
1604 will change soon, there is no guarantee either.
1605 You better know what you are doing here.
1607 Note: overly (ab)use of the default environment is
1608 discouraged. Make sure to check other ways to preset
1609 the environment like the autoscript function or the
1612 - DataFlash Support:
1613 CONFIG_HAS_DATAFLASH
1615 Defining this option enables DataFlash features and
1616 allows to read/write in Dataflash via the standard
1619 - SystemACE Support:
1622 Adding this option adds support for Xilinx SystemACE
1623 chips attached via some sort of local bus. The address
1624 of the chip must alsh be defined in the
1625 CFG_SYSTEMACE_BASE macro. For example:
1627 #define CONFIG_SYSTEMACE
1628 #define CFG_SYSTEMACE_BASE 0xf0000000
1630 When SystemACE support is added, the "ace" device type
1631 becomes available to the fat commands, i.e. fatls.
1633 - TFTP Fixed UDP Port:
1636 If this is defined, the environment variable tftpsrcp
1637 is used to supply the TFTP UDP source port value.
1638 If tftpsrcp isn't defined, the normal pseudo-random port
1639 number generator is used.
1641 Also, the environment variable tftpdstp is used to supply
1642 the TFTP UDP destination port value. If tftpdstp isn't
1643 defined, the normal port 69 is used.
1645 The purpose for tftpsrcp is to allow a TFTP server to
1646 blindly start the TFTP transfer using the pre-configured
1647 target IP address and UDP port. This has the effect of
1648 "punching through" the (Windows XP) firewall, allowing
1649 the remainder of the TFTP transfer to proceed normally.
1650 A better solution is to properly configure the firewall,
1651 but sometimes that is not allowed.
1653 - Show boot progress:
1654 CONFIG_SHOW_BOOT_PROGRESS
1656 Defining this option allows to add some board-
1657 specific code (calling a user-provided function
1658 "show_boot_progress(int)") that enables you to show
1659 the system's boot progress on some display (for
1660 example, some LED's) on your board. At the moment,
1661 the following checkpoints are implemented:
1664 1 common/cmd_bootm.c before attempting to boot an image
1665 -1 common/cmd_bootm.c Image header has bad magic number
1666 2 common/cmd_bootm.c Image header has correct magic number
1667 -2 common/cmd_bootm.c Image header has bad checksum
1668 3 common/cmd_bootm.c Image header has correct checksum
1669 -3 common/cmd_bootm.c Image data has bad checksum
1670 4 common/cmd_bootm.c Image data has correct checksum
1671 -4 common/cmd_bootm.c Image is for unsupported architecture
1672 5 common/cmd_bootm.c Architecture check OK
1673 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1674 6 common/cmd_bootm.c Image Type check OK
1675 -6 common/cmd_bootm.c gunzip uncompression error
1676 -7 common/cmd_bootm.c Unimplemented compression type
1677 7 common/cmd_bootm.c Uncompression OK
1678 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1679 8 common/cmd_bootm.c Image Type check OK
1680 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1681 9 common/cmd_bootm.c Start initial ramdisk verification
1682 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1683 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1684 10 common/cmd_bootm.c Ramdisk header is OK
1685 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1686 11 common/cmd_bootm.c Ramdisk data has correct checksum
1687 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1688 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1689 13 common/cmd_bootm.c Start multifile image verification
1690 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1691 15 common/cmd_bootm.c All preparation done, transferring control to OS
1693 -30 lib_ppc/board.c Fatal error, hang the system
1694 -31 post/post.c POST test failed, detected by post_output_backlog()
1695 -32 post/post.c POST test failed, detected by post_run_single()
1697 34 common/cmd_doc.c before loading a Image from a DOC device
1698 -35 common/cmd_doc.c Bad usage of "doc" command
1699 35 common/cmd_doc.c correct usage of "doc" command
1700 -36 common/cmd_doc.c No boot device
1701 36 common/cmd_doc.c correct boot device
1702 -37 common/cmd_doc.c Unknown Chip ID on boot device
1703 37 common/cmd_doc.c correct chip ID found, device available
1704 -38 common/cmd_doc.c Read Error on boot device
1705 38 common/cmd_doc.c reading Image header from DOC device OK
1706 -39 common/cmd_doc.c Image header has bad magic number
1707 39 common/cmd_doc.c Image header has correct magic number
1708 -40 common/cmd_doc.c Error reading Image from DOC device
1709 40 common/cmd_doc.c Image header has correct magic number
1710 41 common/cmd_ide.c before loading a Image from a IDE device
1711 -42 common/cmd_ide.c Bad usage of "ide" command
1712 42 common/cmd_ide.c correct usage of "ide" command
1713 -43 common/cmd_ide.c No boot device
1714 43 common/cmd_ide.c boot device found
1715 -44 common/cmd_ide.c Device not available
1716 44 common/cmd_ide.c Device available
1717 -45 common/cmd_ide.c wrong partition selected
1718 45 common/cmd_ide.c partition selected
1719 -46 common/cmd_ide.c Unknown partition table
1720 46 common/cmd_ide.c valid partition table found
1721 -47 common/cmd_ide.c Invalid partition type
1722 47 common/cmd_ide.c correct partition type
1723 -48 common/cmd_ide.c Error reading Image Header on boot device
1724 48 common/cmd_ide.c reading Image Header from IDE device OK
1725 -49 common/cmd_ide.c Image header has bad magic number
1726 49 common/cmd_ide.c Image header has correct magic number
1727 -50 common/cmd_ide.c Image header has bad checksum
1728 50 common/cmd_ide.c Image header has correct checksum
1729 -51 common/cmd_ide.c Error reading Image from IDE device
1730 51 common/cmd_ide.c reading Image from IDE device OK
1731 52 common/cmd_nand.c before loading a Image from a NAND device
1732 -53 common/cmd_nand.c Bad usage of "nand" command
1733 53 common/cmd_nand.c correct usage of "nand" command
1734 -54 common/cmd_nand.c No boot device
1735 54 common/cmd_nand.c boot device found
1736 -55 common/cmd_nand.c Unknown Chip ID on boot device
1737 55 common/cmd_nand.c correct chip ID found, device available
1738 -56 common/cmd_nand.c Error reading Image Header on boot device
1739 56 common/cmd_nand.c reading Image Header from NAND device OK
1740 -57 common/cmd_nand.c Image header has bad magic number
1741 57 common/cmd_nand.c Image header has correct magic number
1742 -58 common/cmd_nand.c Error reading Image from NAND device
1743 58 common/cmd_nand.c reading Image from NAND device OK
1745 -60 common/env_common.c Environment has a bad CRC, using default
1747 64 net/eth.c starting with Ethernetconfiguration.
1748 -64 net/eth.c no Ethernet found.
1749 65 net/eth.c Ethernet found.
1751 -80 common/cmd_net.c usage wrong
1752 80 common/cmd_net.c before calling NetLoop()
1753 -81 common/cmd_net.c some error in NetLoop() occured
1754 81 common/cmd_net.c NetLoop() back without error
1755 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1756 82 common/cmd_net.c trying automatic boot
1757 83 common/cmd_net.c running autoscript
1758 -83 common/cmd_net.c some error in automatic boot or autoscript
1759 84 common/cmd_net.c end without errors
1764 [so far only for SMDK2400 and TRAB boards]
1766 - Modem support endable:
1767 CONFIG_MODEM_SUPPORT
1769 - RTS/CTS Flow control enable:
1772 - Modem debug support:
1773 CONFIG_MODEM_SUPPORT_DEBUG
1775 Enables debugging stuff (char screen[1024], dbg())
1776 for modem support. Useful only with BDI2000.
1778 - Interrupt support (PPC):
1780 There are common interrupt_init() and timer_interrupt()
1781 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1782 for cpu specific initialization. interrupt_init_cpu()
1783 should set decrementer_count to appropriate value. If
1784 cpu resets decrementer automatically after interrupt
1785 (ppc4xx) it should set decrementer_count to zero.
1786 timer_interrupt() calls timer_interrupt_cpu() for cpu
1787 specific handling. If board has watchdog / status_led
1788 / other_activity_monitor it works automatically from
1789 general timer_interrupt().
1793 In the target system modem support is enabled when a
1794 specific key (key combination) is pressed during
1795 power-on. Otherwise U-Boot will boot normally
1796 (autoboot). The key_pressed() fuction is called from
1797 board_init(). Currently key_pressed() is a dummy
1798 function, returning 1 and thus enabling modem
1801 If there are no modem init strings in the
1802 environment, U-Boot proceed to autoboot; the
1803 previous output (banner, info printfs) will be
1806 See also: doc/README.Modem
1809 Configuration Settings:
1810 -----------------------
1812 - CFG_LONGHELP: Defined when you want long help messages included;
1813 undefine this when you're short of memory.
1815 - CFG_PROMPT: This is what U-Boot prints on the console to
1816 prompt for user input.
1818 - CFG_CBSIZE: Buffer size for input from the Console
1820 - CFG_PBSIZE: Buffer size for Console output
1822 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1824 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1825 the application (usually a Linux kernel) when it is
1828 - CFG_BAUDRATE_TABLE:
1829 List of legal baudrate settings for this board.
1831 - CFG_CONSOLE_INFO_QUIET
1832 Suppress display of console information at boot.
1834 - CFG_CONSOLE_IS_IN_ENV
1835 If the board specific function
1836 extern int overwrite_console (void);
1837 returns 1, the stdin, stderr and stdout are switched to the
1838 serial port, else the settings in the environment are used.
1840 - CFG_CONSOLE_OVERWRITE_ROUTINE
1841 Enable the call to overwrite_console().
1843 - CFG_CONSOLE_ENV_OVERWRITE
1844 Enable overwrite of previous console environment settings.
1846 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1847 Begin and End addresses of the area used by the
1851 Enable an alternate, more extensive memory test.
1853 - CFG_MEMTEST_SCRATCH:
1854 Scratch address used by the alternate memory test
1855 You only need to set this if address zero isn't writeable
1857 - CFG_TFTP_LOADADDR:
1858 Default load address for network file downloads
1860 - CFG_LOADS_BAUD_CHANGE:
1861 Enable temporary baudrate change while serial download
1864 Physical start address of SDRAM. _Must_ be 0 here.
1867 Physical start address of Motherboard I/O (if using a
1871 Physical start address of Flash memory.
1874 Physical start address of boot monitor code (set by
1875 make config files to be same as the text base address
1876 (TEXT_BASE) used when linking) - same as
1877 CFG_FLASH_BASE when booting from flash.
1880 Size of memory reserved for monitor code, used to
1881 determine _at_compile_time_ (!) if the environment is
1882 embedded within the U-Boot image, or in a separate
1886 Size of DRAM reserved for malloc() use.
1889 Normally compressed uImages are limited to an
1890 uncompressed size of 8 MBytes. If this is not enough,
1891 you can define CFG_BOOTM_LEN in your board config file
1892 to adjust this setting to your needs.
1895 Maximum size of memory mapped by the startup code of
1896 the Linux kernel; all data that must be processed by
1897 the Linux kernel (bd_info, boot arguments, eventually
1898 initrd image) must be put below this limit.
1900 - CFG_MAX_FLASH_BANKS:
1901 Max number of Flash memory banks
1903 - CFG_MAX_FLASH_SECT:
1904 Max number of sectors on a Flash chip
1906 - CFG_FLASH_ERASE_TOUT:
1907 Timeout for Flash erase operations (in ms)
1909 - CFG_FLASH_WRITE_TOUT:
1910 Timeout for Flash write operations (in ms)
1912 - CFG_FLASH_LOCK_TOUT
1913 Timeout for Flash set sector lock bit operation (in ms)
1915 - CFG_FLASH_UNLOCK_TOUT
1916 Timeout for Flash clear lock bits operation (in ms)
1918 - CFG_FLASH_PROTECTION
1919 If defined, hardware flash sectors protection is used
1920 instead of U-Boot software protection.
1922 - CFG_DIRECT_FLASH_TFTP:
1924 Enable TFTP transfers directly to flash memory;
1925 without this option such a download has to be
1926 performed in two steps: (1) download to RAM, and (2)
1927 copy from RAM to flash.
1929 The two-step approach is usually more reliable, since
1930 you can check if the download worked before you erase
1931 the flash, but in some situations (when sytem RAM is
1932 too limited to allow for a tempory copy of the
1933 downloaded image) this option may be very useful.
1936 Define if the flash driver uses extra elements in the
1937 common flash structure for storing flash geometry.
1939 - CFG_FLASH_CFI_DRIVER
1940 This option also enables the building of the cfi_flash driver
1941 in the drivers directory
1943 - CFG_FLASH_QUIET_TEST
1944 If this option is defined, the common CFI flash doesn't
1945 print it's warning upon not recognized FLASH banks. This
1946 is useful, if some of the configured banks are only
1947 optionally available.
1949 - CONFIG_FLASH_SHOW_PROGRESS
1950 If defined (must be an integer), print out countdown
1951 digits and dots. Recommended value: 45 (9..1) for 80
1952 column displays, 15 (3..1) for 40 column displays.
1954 - CFG_RX_ETH_BUFFER:
1955 Defines the number of ethernet receive buffers. On some
1956 ethernet controllers it is recommended to set this value
1957 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1958 buffers can be full shortly after enabling the interface
1959 on high ethernet traffic.
1960 Defaults to 4 if not defined.
1962 The following definitions that deal with the placement and management
1963 of environment data (variable area); in general, we support the
1964 following configurations:
1966 - CFG_ENV_IS_IN_FLASH:
1968 Define this if the environment is in flash memory.
1970 a) The environment occupies one whole flash sector, which is
1971 "embedded" in the text segment with the U-Boot code. This
1972 happens usually with "bottom boot sector" or "top boot
1973 sector" type flash chips, which have several smaller
1974 sectors at the start or the end. For instance, such a
1975 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1976 such a case you would place the environment in one of the
1977 4 kB sectors - with U-Boot code before and after it. With
1978 "top boot sector" type flash chips, you would put the
1979 environment in one of the last sectors, leaving a gap
1980 between U-Boot and the environment.
1984 Offset of environment data (variable area) to the
1985 beginning of flash memory; for instance, with bottom boot
1986 type flash chips the second sector can be used: the offset
1987 for this sector is given here.
1989 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1993 This is just another way to specify the start address of
1994 the flash sector containing the environment (instead of
1997 - CFG_ENV_SECT_SIZE:
1999 Size of the sector containing the environment.
2002 b) Sometimes flash chips have few, equal sized, BIG sectors.
2003 In such a case you don't want to spend a whole sector for
2008 If you use this in combination with CFG_ENV_IS_IN_FLASH
2009 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2010 of this flash sector for the environment. This saves
2011 memory for the RAM copy of the environment.
2013 It may also save flash memory if you decide to use this
2014 when your environment is "embedded" within U-Boot code,
2015 since then the remainder of the flash sector could be used
2016 for U-Boot code. It should be pointed out that this is
2017 STRONGLY DISCOURAGED from a robustness point of view:
2018 updating the environment in flash makes it always
2019 necessary to erase the WHOLE sector. If something goes
2020 wrong before the contents has been restored from a copy in
2021 RAM, your target system will be dead.
2023 - CFG_ENV_ADDR_REDUND
2026 These settings describe a second storage area used to hold
2027 a redundand copy of the environment data, so that there is
2028 a valid backup copy in case there is a power failure during
2029 a "saveenv" operation.
2031 BE CAREFUL! Any changes to the flash layout, and some changes to the
2032 source code will make it necessary to adapt <board>/u-boot.lds*
2036 - CFG_ENV_IS_IN_NVRAM:
2038 Define this if you have some non-volatile memory device
2039 (NVRAM, battery buffered SRAM) which you want to use for the
2045 These two #defines are used to determin the memory area you
2046 want to use for environment. It is assumed that this memory
2047 can just be read and written to, without any special
2050 BE CAREFUL! The first access to the environment happens quite early
2051 in U-Boot initalization (when we try to get the setting of for the
2052 console baudrate). You *MUST* have mappend your NVRAM area then, or
2055 Please note that even with NVRAM we still use a copy of the
2056 environment in RAM: we could work on NVRAM directly, but we want to
2057 keep settings there always unmodified except somebody uses "saveenv"
2058 to save the current settings.
2061 - CFG_ENV_IS_IN_EEPROM:
2063 Use this if you have an EEPROM or similar serial access
2064 device and a driver for it.
2069 These two #defines specify the offset and size of the
2070 environment area within the total memory of your EEPROM.
2072 - CFG_I2C_EEPROM_ADDR:
2073 If defined, specified the chip address of the EEPROM device.
2074 The default address is zero.
2076 - CFG_EEPROM_PAGE_WRITE_BITS:
2077 If defined, the number of bits used to address bytes in a
2078 single page in the EEPROM device. A 64 byte page, for example
2079 would require six bits.
2081 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2082 If defined, the number of milliseconds to delay between
2083 page writes. The default is zero milliseconds.
2085 - CFG_I2C_EEPROM_ADDR_LEN:
2086 The length in bytes of the EEPROM memory array address. Note
2087 that this is NOT the chip address length!
2089 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2090 EEPROM chips that implement "address overflow" are ones
2091 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2092 address and the extra bits end up in the "chip address" bit
2093 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2096 Note that we consider the length of the address field to
2097 still be one byte because the extra address bits are hidden
2098 in the chip address.
2101 The size in bytes of the EEPROM device.
2104 - CFG_ENV_IS_IN_DATAFLASH:
2106 Define this if you have a DataFlash memory device which you
2107 want to use for the environment.
2113 These three #defines specify the offset and size of the
2114 environment area within the total memory of your DataFlash placed
2115 at the specified address.
2117 - CFG_ENV_IS_IN_NAND:
2119 Define this if you have a NAND device which you want to use
2120 for the environment.
2125 These two #defines specify the offset and size of the environment
2126 area within the first NAND device.
2128 - CFG_ENV_OFFSET_REDUND
2130 This setting describes a second storage area of CFG_ENV_SIZE
2131 size used to hold a redundant copy of the environment data,
2132 so that there is a valid backup copy in case there is a
2133 power failure during a "saveenv" operation.
2135 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2136 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2137 the NAND devices block size.
2139 - CFG_SPI_INIT_OFFSET
2141 Defines offset to the initial SPI buffer area in DPRAM. The
2142 area is used at an early stage (ROM part) if the environment
2143 is configured to reside in the SPI EEPROM: We need a 520 byte
2144 scratch DPRAM area. It is used between the two initialization
2145 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2146 to be a good choice since it makes it far enough from the
2147 start of the data area as well as from the stack pointer.
2149 Please note that the environment is read-only until the monitor
2150 has been relocated to RAM and a RAM copy of the environment has been
2151 created; also, when using EEPROM you will have to use getenv_r()
2152 until then to read environment variables.
2154 The environment is protected by a CRC32 checksum. Before the monitor
2155 is relocated into RAM, as a result of a bad CRC you will be working
2156 with the compiled-in default environment - *silently*!!! [This is
2157 necessary, because the first environment variable we need is the
2158 "baudrate" setting for the console - if we have a bad CRC, we don't
2159 have any device yet where we could complain.]
2161 Note: once the monitor has been relocated, then it will complain if
2162 the default environment is used; a new CRC is computed as soon as you
2163 use the "saveenv" command to store a valid environment.
2165 - CFG_FAULT_ECHO_LINK_DOWN:
2166 Echo the inverted Ethernet link state to the fault LED.
2168 Note: If this option is active, then CFG_FAULT_MII_ADDR
2169 also needs to be defined.
2171 - CFG_FAULT_MII_ADDR:
2172 MII address of the PHY to check for the Ethernet link state.
2174 - CFG_64BIT_VSPRINTF:
2175 Makes vsprintf (and all *printf functions) support printing
2176 of 64bit values by using the L quantifier
2178 - CFG_64BIT_STRTOUL:
2179 Adds simple_strtoull that returns a 64bit value
2181 Low Level (hardware related) configuration options:
2182 ---------------------------------------------------
2184 - CFG_CACHELINE_SIZE:
2185 Cache Line Size of the CPU.
2188 Default address of the IMMR after system reset.
2190 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2191 and RPXsuper) to be able to adjust the position of
2192 the IMMR register after a reset.
2194 - Floppy Disk Support:
2195 CFG_FDC_DRIVE_NUMBER
2197 the default drive number (default value 0)
2201 defines the spacing between fdc chipset registers
2206 defines the offset of register from address. It
2207 depends on which part of the data bus is connected to
2208 the fdc chipset. (default value 0)
2210 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2211 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2214 if CFG_FDC_HW_INIT is defined, then the function
2215 fdc_hw_init() is called at the beginning of the FDC
2216 setup. fdc_hw_init() must be provided by the board
2217 source code. It is used to make hardware dependant
2220 - CFG_IMMR: Physical address of the Internal Memory.
2221 DO NOT CHANGE unless you know exactly what you're
2222 doing! (11-4) [MPC8xx/82xx systems only]
2224 - CFG_INIT_RAM_ADDR:
2226 Start address of memory area that can be used for
2227 initial data and stack; please note that this must be
2228 writable memory that is working WITHOUT special
2229 initialization, i. e. you CANNOT use normal RAM which
2230 will become available only after programming the
2231 memory controller and running certain initialization
2234 U-Boot uses the following memory types:
2235 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2236 - MPC824X: data cache
2237 - PPC4xx: data cache
2239 - CFG_GBL_DATA_OFFSET:
2241 Offset of the initial data structure in the memory
2242 area defined by CFG_INIT_RAM_ADDR. Usually
2243 CFG_GBL_DATA_OFFSET is chosen such that the initial
2244 data is located at the end of the available space
2245 (sometimes written as (CFG_INIT_RAM_END -
2246 CFG_INIT_DATA_SIZE), and the initial stack is just
2247 below that area (growing from (CFG_INIT_RAM_ADDR +
2248 CFG_GBL_DATA_OFFSET) downward.
2251 On the MPC824X (or other systems that use the data
2252 cache for initial memory) the address chosen for
2253 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2254 point to an otherwise UNUSED address space between
2255 the top of RAM and the start of the PCI space.
2257 - CFG_SIUMCR: SIU Module Configuration (11-6)
2259 - CFG_SYPCR: System Protection Control (11-9)
2261 - CFG_TBSCR: Time Base Status and Control (11-26)
2263 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2265 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2267 - CFG_SCCR: System Clock and reset Control Register (15-27)
2269 - CFG_OR_TIMING_SDRAM:
2273 periodic timer for refresh
2275 - CFG_DER: Debug Event Register (37-47)
2277 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2278 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2279 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2281 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2283 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2284 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2285 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2286 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2288 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2289 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2290 Machine Mode Register and Memory Periodic Timer
2291 Prescaler definitions (SDRAM timing)
2293 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2294 enable I2C microcode relocation patch (MPC8xx);
2295 define relocation offset in DPRAM [DSP2]
2297 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2298 enable SMC microcode relocation patch (MPC8xx);
2299 define relocation offset in DPRAM [SMC1]
2301 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2302 enable SPI microcode relocation patch (MPC8xx);
2303 define relocation offset in DPRAM [SCC4]
2306 Use OSCM clock mode on MBX8xx board. Be careful,
2307 wrong setting might damage your board. Read
2308 doc/README.MBX before setting this variable!
2310 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2311 Offset of the bootmode word in DPRAM used by post
2312 (Power On Self Tests). This definition overrides
2313 #define'd default value in commproc.h resp.
2316 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2317 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2318 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2319 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2320 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2321 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2322 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2323 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2324 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2327 Get DDR timing information from an I2C EEPROM. Common with pluggable
2328 memory modules such as SODIMMs
2330 I2C address of the SPD EEPROM
2333 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2334 Note that the value must resolve to something your driver can deal with.
2336 - CFG_83XX_DDR_USES_CS0
2337 Only for 83xx systems. If specified, then DDR should be configured
2338 using CS0 and CS1 instead of CS2 and CS3.
2340 - CFG_83XX_DDR_USES_CS0
2341 Only for 83xx systems. If specified, then DDR should be configured
2342 using CS0 and CS1 instead of CS2 and CS3.
2344 - CONFIG_ETHER_ON_FEC[12]
2345 Define to enable FEC[12] on a 8xx series processor.
2347 - CONFIG_FEC[12]_PHY
2348 Define to the hardcoded PHY address which corresponds
2349 to the given FEC; i. e.
2350 #define CONFIG_FEC1_PHY 4
2351 means that the PHY with address 4 is connected to FEC1
2353 When set to -1, means to probe for first available.
2355 - CONFIG_FEC[12]_PHY_NORXERR
2356 The PHY does not have a RXERR line (RMII only).
2357 (so program the FEC to ignore it).
2360 Enable RMII mode for all FECs.
2361 Note that this is a global option, we can't
2362 have one FEC in standard MII mode and another in RMII mode.
2364 - CONFIG_CRC32_VERIFY
2365 Add a verify option to the crc32 command.
2368 => crc32 -v <address> <count> <crc32>
2370 Where address/count indicate a memory area
2371 and crc32 is the correct crc32 which the
2375 Add the "loopw" memory command. This only takes effect if
2376 the memory commands are activated globally (CONFIG_CMD_MEM).
2379 Add the "mdc" and "mwc" memory commands. These are cyclic
2384 This command will print 4 bytes (10,11,12,13) each 500 ms.
2386 => mwc.l 100 12345678 10
2387 This command will write 12345678 to address 100 all 10 ms.
2389 This only takes effect if the memory commands are activated
2390 globally (CONFIG_CMD_MEM).
2392 - CONFIG_SKIP_LOWLEVEL_INIT
2393 - CONFIG_SKIP_RELOCATE_UBOOT
2395 [ARM only] If these variables are defined, then
2396 certain low level initializations (like setting up
2397 the memory controller) are omitted and/or U-Boot does
2398 not relocate itself into RAM.
2399 Normally these variables MUST NOT be defined. The
2400 only exception is when U-Boot is loaded (to RAM) by
2401 some other boot loader or by a debugger which
2402 performs these intializations itself.
2405 Building the Software:
2406 ======================
2408 Building U-Boot has been tested in native PPC environments (on a
2409 PowerBook G3 running LinuxPPC 2000) and in cross environments
2410 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2413 If you are not using a native PPC environment, it is assumed that you
2414 have the GNU cross compiling tools available in your path and named
2415 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2416 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2417 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2420 CROSS_COMPILE = ppc_4xx-
2423 U-Boot is intended to be simple to build. After installing the
2424 sources you must configure U-Boot for one specific board type. This
2429 where "NAME_config" is the name of one of the existing
2430 configurations; see the main Makefile for supported names.
2432 Note: for some board special configuration names may exist; check if
2433 additional information is available from the board vendor; for
2434 instance, the TQM823L systems are available without (standard)
2435 or with LCD support. You can select such additional "features"
2436 when chosing the configuration, i. e.
2439 - will configure for a plain TQM823L, i. e. no LCD support
2441 make TQM823L_LCD_config
2442 - will configure for a TQM823L with U-Boot console on LCD
2447 Finally, type "make all", and you should get some working U-Boot
2448 images ready for download to / installation on your system:
2450 - "u-boot.bin" is a raw binary image
2451 - "u-boot" is an image in ELF binary format
2452 - "u-boot.srec" is in Motorola S-Record format
2454 By default the build is performed locally and the objects are saved
2455 in the source directory. One of the two methods can be used to change
2456 this behavior and build U-Boot to some external directory:
2458 1. Add O= to the make command line invocations:
2460 make O=/tmp/build distclean
2461 make O=/tmp/build NAME_config
2462 make O=/tmp/build all
2464 2. Set environment variable BUILD_DIR to point to the desired location:
2466 export BUILD_DIR=/tmp/build
2471 Note that the command line "O=" setting overrides the BUILD_DIR environment
2475 Please be aware that the Makefiles assume you are using GNU make, so
2476 for instance on NetBSD you might need to use "gmake" instead of
2480 If the system board that you have is not listed, then you will need
2481 to port U-Boot to your hardware platform. To do this, follow these
2484 1. Add a new configuration option for your board to the toplevel
2485 "Makefile" and to the "MAKEALL" script, using the existing
2486 entries as examples. Note that here and at many other places
2487 boards and other names are listed in alphabetical sort order. Please
2489 2. Create a new directory to hold your board specific code. Add any
2490 files you need. In your board directory, you will need at least
2491 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2492 3. Create a new configuration file "include/configs/<board>.h" for
2494 3. If you're porting U-Boot to a new CPU, then also create a new
2495 directory to hold your CPU specific code. Add any files you need.
2496 4. Run "make <board>_config" with your new name.
2497 5. Type "make", and you should get a working "u-boot.srec" file
2498 to be installed on your target system.
2499 6. Debug and solve any problems that might arise.
2500 [Of course, this last step is much harder than it sounds.]
2503 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2504 ==============================================================
2506 If you have modified U-Boot sources (for instance added a new board
2507 or support for new devices, a new CPU, etc.) you are expected to
2508 provide feedback to the other developers. The feedback normally takes
2509 the form of a "patch", i. e. a context diff against a certain (latest
2510 official or latest in CVS) version of U-Boot sources.
2512 But before you submit such a patch, please verify that your modifi-
2513 cation did not break existing code. At least make sure that *ALL* of
2514 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2515 just run the "MAKEALL" script, which will configure and build U-Boot
2516 for ALL supported system. Be warned, this will take a while. You can
2517 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2518 environment variable to the script, i. e. to use the cross tools from
2519 MontaVista's Hard Hat Linux you can type
2521 CROSS_COMPILE=ppc_8xx- MAKEALL
2523 or to build on a native PowerPC system you can type
2525 CROSS_COMPILE=' ' MAKEALL
2527 When using the MAKEALL script, the default behaviour is to build U-Boot
2528 in the source directory. This location can be changed by setting the
2529 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2530 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2531 <source dir>/LOG directory. This default location can be changed by
2532 setting the MAKEALL_LOGDIR environment variable. For example:
2534 export BUILD_DIR=/tmp/build
2535 export MAKEALL_LOGDIR=/tmp/log
2536 CROSS_COMPILE=ppc_8xx- MAKEALL
2538 With the above settings build objects are saved in the /tmp/build, log
2539 files are saved in the /tmp/log and the source tree remains clean during
2540 the whole build process.
2543 See also "U-Boot Porting Guide" below.
2546 Monitor Commands - Overview:
2547 ============================
2549 go - start application at address 'addr'
2550 run - run commands in an environment variable
2551 bootm - boot application image from memory
2552 bootp - boot image via network using BootP/TFTP protocol
2553 tftpboot- boot image via network using TFTP protocol
2554 and env variables "ipaddr" and "serverip"
2555 (and eventually "gatewayip")
2556 rarpboot- boot image via network using RARP/TFTP protocol
2557 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2558 loads - load S-Record file over serial line
2559 loadb - load binary file over serial line (kermit mode)
2561 mm - memory modify (auto-incrementing)
2562 nm - memory modify (constant address)
2563 mw - memory write (fill)
2565 cmp - memory compare
2566 crc32 - checksum calculation
2567 imd - i2c memory display
2568 imm - i2c memory modify (auto-incrementing)
2569 inm - i2c memory modify (constant address)
2570 imw - i2c memory write (fill)
2571 icrc32 - i2c checksum calculation
2572 iprobe - probe to discover valid I2C chip addresses
2573 iloop - infinite loop on address range
2574 isdram - print SDRAM configuration information
2575 sspi - SPI utility commands
2576 base - print or set address offset
2577 printenv- print environment variables
2578 setenv - set environment variables
2579 saveenv - save environment variables to persistent storage
2580 protect - enable or disable FLASH write protection
2581 erase - erase FLASH memory
2582 flinfo - print FLASH memory information
2583 bdinfo - print Board Info structure
2584 iminfo - print header information for application image
2585 coninfo - print console devices and informations
2586 ide - IDE sub-system
2587 loop - infinite loop on address range
2588 loopw - infinite write loop on address range
2589 mtest - simple RAM test
2590 icache - enable or disable instruction cache
2591 dcache - enable or disable data cache
2592 reset - Perform RESET of the CPU
2593 echo - echo args to console
2594 version - print monitor version
2595 help - print online help
2596 ? - alias for 'help'
2599 Monitor Commands - Detailed Description:
2600 ========================================
2604 For now: just type "help <command>".
2607 Environment Variables:
2608 ======================
2610 U-Boot supports user configuration using Environment Variables which
2611 can be made persistent by saving to Flash memory.
2613 Environment Variables are set using "setenv", printed using
2614 "printenv", and saved to Flash using "saveenv". Using "setenv"
2615 without a value can be used to delete a variable from the
2616 environment. As long as you don't save the environment you are
2617 working with an in-memory copy. In case the Flash area containing the
2618 environment is erased by accident, a default environment is provided.
2620 Some configuration options can be set using Environment Variables:
2622 baudrate - see CONFIG_BAUDRATE
2624 bootdelay - see CONFIG_BOOTDELAY
2626 bootcmd - see CONFIG_BOOTCOMMAND
2628 bootargs - Boot arguments when booting an RTOS image
2630 bootfile - Name of the image to load with TFTP
2632 autoload - if set to "no" (any string beginning with 'n'),
2633 "bootp" will just load perform a lookup of the
2634 configuration from the BOOTP server, but not try to
2635 load any image using TFTP
2637 autostart - if set to "yes", an image loaded using the "bootp",
2638 "rarpboot", "tftpboot" or "diskboot" commands will
2639 be automatically started (by internally calling
2642 If set to "no", a standalone image passed to the
2643 "bootm" command will be copied to the load address
2644 (and eventually uncompressed), but NOT be started.
2645 This can be used to load and uncompress arbitrary
2648 i2cfast - (PPC405GP|PPC405EP only)
2649 if set to 'y' configures Linux I2C driver for fast
2650 mode (400kHZ). This environment variable is used in
2651 initialization code. So, for changes to be effective
2652 it must be saved and board must be reset.
2654 initrd_high - restrict positioning of initrd images:
2655 If this variable is not set, initrd images will be
2656 copied to the highest possible address in RAM; this
2657 is usually what you want since it allows for
2658 maximum initrd size. If for some reason you want to
2659 make sure that the initrd image is loaded below the
2660 CFG_BOOTMAPSZ limit, you can set this environment
2661 variable to a value of "no" or "off" or "0".
2662 Alternatively, you can set it to a maximum upper
2663 address to use (U-Boot will still check that it
2664 does not overwrite the U-Boot stack and data).
2666 For instance, when you have a system with 16 MB
2667 RAM, and want to reserve 4 MB from use by Linux,
2668 you can do this by adding "mem=12M" to the value of
2669 the "bootargs" variable. However, now you must make
2670 sure that the initrd image is placed in the first
2671 12 MB as well - this can be done with
2673 setenv initrd_high 00c00000
2675 If you set initrd_high to 0xFFFFFFFF, this is an
2676 indication to U-Boot that all addresses are legal
2677 for the Linux kernel, including addresses in flash
2678 memory. In this case U-Boot will NOT COPY the
2679 ramdisk at all. This may be useful to reduce the
2680 boot time on your system, but requires that this
2681 feature is supported by your Linux kernel.
2683 ipaddr - IP address; needed for tftpboot command
2685 loadaddr - Default load address for commands like "bootp",
2686 "rarpboot", "tftpboot", "loadb" or "diskboot"
2688 loads_echo - see CONFIG_LOADS_ECHO
2690 serverip - TFTP server IP address; needed for tftpboot command
2692 bootretry - see CONFIG_BOOT_RETRY_TIME
2694 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2696 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2698 ethprime - When CONFIG_NET_MULTI is enabled controls which
2699 interface is used first.
2701 ethact - When CONFIG_NET_MULTI is enabled controls which
2702 interface is currently active. For example you
2703 can do the following
2705 => setenv ethact FEC ETHERNET
2706 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2707 => setenv ethact SCC ETHERNET
2708 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2710 ethrotate - When set to "no" U-Boot does not go through all
2711 available network interfaces.
2712 It just stays at the currently selected interface.
2714 netretry - When set to "no" each network operation will
2715 either succeed or fail without retrying.
2716 When set to "once" the network operation will
2717 fail when all the available network interfaces
2718 are tried once without success.
2719 Useful on scripts which control the retry operation
2722 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2723 if set load address for the npe microcode
2725 tftpsrcport - If this is set, the value is used for TFTP's
2728 tftpdstport - If this is set, the value is used for TFTP's UDP
2729 destination port instead of the Well Know Port 69.
2731 vlan - When set to a value < 4095 the traffic over
2732 ethernet is encapsulated/received over 802.1q
2735 The following environment variables may be used and automatically
2736 updated by the network boot commands ("bootp" and "rarpboot"),
2737 depending the information provided by your boot server:
2739 bootfile - see above
2740 dnsip - IP address of your Domain Name Server
2741 dnsip2 - IP address of your secondary Domain Name Server
2742 gatewayip - IP address of the Gateway (Router) to use
2743 hostname - Target hostname
2745 netmask - Subnet Mask
2746 rootpath - Pathname of the root filesystem on the NFS server
2747 serverip - see above
2750 There are two special Environment Variables:
2752 serial# - contains hardware identification information such
2753 as type string and/or serial number
2754 ethaddr - Ethernet address
2756 These variables can be set only once (usually during manufacturing of
2757 the board). U-Boot refuses to delete or overwrite these variables
2758 once they have been set once.
2761 Further special Environment Variables:
2763 ver - Contains the U-Boot version string as printed
2764 with the "version" command. This variable is
2765 readonly (see CONFIG_VERSION_VARIABLE).
2768 Please note that changes to some configuration parameters may take
2769 only effect after the next boot (yes, that's just like Windoze :-).
2772 Command Line Parsing:
2773 =====================
2775 There are two different command line parsers available with U-Boot:
2776 the old "simple" one, and the much more powerful "hush" shell:
2778 Old, simple command line parser:
2779 --------------------------------
2781 - supports environment variables (through setenv / saveenv commands)
2782 - several commands on one line, separated by ';'
2783 - variable substitution using "... ${name} ..." syntax
2784 - special characters ('$', ';') can be escaped by prefixing with '\',
2786 setenv bootcmd bootm \${address}
2787 - You can also escape text by enclosing in single apostrophes, for example:
2788 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2793 - similar to Bourne shell, with control structures like
2794 if...then...else...fi, for...do...done; while...do...done,
2795 until...do...done, ...
2796 - supports environment ("global") variables (through setenv / saveenv
2797 commands) and local shell variables (through standard shell syntax
2798 "name=value"); only environment variables can be used with "run"
2804 (1) If a command line (or an environment variable executed by a "run"
2805 command) contains several commands separated by semicolon, and
2806 one of these commands fails, then the remaining commands will be
2809 (2) If you execute several variables with one call to run (i. e.
2810 calling run with a list af variables as arguments), any failing
2811 command will cause "run" to terminate, i. e. the remaining
2812 variables are not executed.
2814 Note for Redundant Ethernet Interfaces:
2815 =======================================
2817 Some boards come with redundant ethernet interfaces; U-Boot supports
2818 such configurations and is capable of automatic selection of a
2819 "working" interface when needed. MAC assignment works as follows:
2821 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2822 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2823 "eth1addr" (=>eth1), "eth2addr", ...
2825 If the network interface stores some valid MAC address (for instance
2826 in SROM), this is used as default address if there is NO correspon-
2827 ding setting in the environment; if the corresponding environment
2828 variable is set, this overrides the settings in the card; that means:
2830 o If the SROM has a valid MAC address, and there is no address in the
2831 environment, the SROM's address is used.
2833 o If there is no valid address in the SROM, and a definition in the
2834 environment exists, then the value from the environment variable is
2837 o If both the SROM and the environment contain a MAC address, and
2838 both addresses are the same, this MAC address is used.
2840 o If both the SROM and the environment contain a MAC address, and the
2841 addresses differ, the value from the environment is used and a
2844 o If neither SROM nor the environment contain a MAC address, an error
2851 The "boot" commands of this monitor operate on "image" files which
2852 can be basicly anything, preceeded by a special header; see the
2853 definitions in include/image.h for details; basicly, the header
2854 defines the following image properties:
2856 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2857 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2858 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2859 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2860 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2861 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2862 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2863 * Compression Type (uncompressed, gzip, bzip2)
2869 The header is marked by a special Magic Number, and both the header
2870 and the data portions of the image are secured against corruption by
2877 Although U-Boot should support any OS or standalone application
2878 easily, the main focus has always been on Linux during the design of
2881 U-Boot includes many features that so far have been part of some
2882 special "boot loader" code within the Linux kernel. Also, any
2883 "initrd" images to be used are no longer part of one big Linux image;
2884 instead, kernel and "initrd" are separate images. This implementation
2885 serves several purposes:
2887 - the same features can be used for other OS or standalone
2888 applications (for instance: using compressed images to reduce the
2889 Flash memory footprint)
2891 - it becomes much easier to port new Linux kernel versions because
2892 lots of low-level, hardware dependent stuff are done by U-Boot
2894 - the same Linux kernel image can now be used with different "initrd"
2895 images; of course this also means that different kernel images can
2896 be run with the same "initrd". This makes testing easier (you don't
2897 have to build a new "zImage.initrd" Linux image when you just
2898 change a file in your "initrd"). Also, a field-upgrade of the
2899 software is easier now.
2905 Porting Linux to U-Boot based systems:
2906 ---------------------------------------
2908 U-Boot cannot save you from doing all the necessary modifications to
2909 configure the Linux device drivers for use with your target hardware
2910 (no, we don't intend to provide a full virtual machine interface to
2913 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2915 Just make sure your machine specific header file (for instance
2916 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2917 Information structure as we define in include/u-boot.h, and make
2918 sure that your definition of IMAP_ADDR uses the same value as your
2919 U-Boot configuration in CFG_IMMR.
2922 Configuring the Linux kernel:
2923 -----------------------------
2925 No specific requirements for U-Boot. Make sure you have some root
2926 device (initial ramdisk, NFS) for your target system.
2929 Building a Linux Image:
2930 -----------------------
2932 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2933 not used. If you use recent kernel source, a new build target
2934 "uImage" will exist which automatically builds an image usable by
2935 U-Boot. Most older kernels also have support for a "pImage" target,
2936 which was introduced for our predecessor project PPCBoot and uses a
2937 100% compatible format.
2946 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2947 encapsulate a compressed Linux kernel image with header information,
2948 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2950 * build a standard "vmlinux" kernel image (in ELF binary format):
2952 * convert the kernel into a raw binary image:
2954 ${CROSS_COMPILE}-objcopy -O binary \
2955 -R .note -R .comment \
2956 -S vmlinux linux.bin
2958 * compress the binary image:
2962 * package compressed binary image for U-Boot:
2964 mkimage -A ppc -O linux -T kernel -C gzip \
2965 -a 0 -e 0 -n "Linux Kernel Image" \
2966 -d linux.bin.gz uImage
2969 The "mkimage" tool can also be used to create ramdisk images for use
2970 with U-Boot, either separated from the Linux kernel image, or
2971 combined into one file. "mkimage" encapsulates the images with a 64
2972 byte header containing information about target architecture,
2973 operating system, image type, compression method, entry points, time
2974 stamp, CRC32 checksums, etc.
2976 "mkimage" can be called in two ways: to verify existing images and
2977 print the header information, or to build new images.
2979 In the first form (with "-l" option) mkimage lists the information
2980 contained in the header of an existing U-Boot image; this includes
2981 checksum verification:
2983 tools/mkimage -l image
2984 -l ==> list image header information
2986 The second form (with "-d" option) is used to build a U-Boot image
2987 from a "data file" which is used as image payload:
2989 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2990 -n name -d data_file image
2991 -A ==> set architecture to 'arch'
2992 -O ==> set operating system to 'os'
2993 -T ==> set image type to 'type'
2994 -C ==> set compression type 'comp'
2995 -a ==> set load address to 'addr' (hex)
2996 -e ==> set entry point to 'ep' (hex)
2997 -n ==> set image name to 'name'
2998 -d ==> use image data from 'datafile'
3000 Right now, all Linux kernels for PowerPC systems use the same load
3001 address (0x00000000), but the entry point address depends on the
3004 - 2.2.x kernels have the entry point at 0x0000000C,
3005 - 2.3.x and later kernels have the entry point at 0x00000000.
3007 So a typical call to build a U-Boot image would read:
3009 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3010 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3011 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3012 > examples/uImage.TQM850L
3013 Image Name: 2.4.4 kernel for TQM850L
3014 Created: Wed Jul 19 02:34:59 2000
3015 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3016 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3017 Load Address: 0x00000000
3018 Entry Point: 0x00000000
3020 To verify the contents of the image (or check for corruption):
3022 -> tools/mkimage -l examples/uImage.TQM850L
3023 Image Name: 2.4.4 kernel for TQM850L
3024 Created: Wed Jul 19 02:34:59 2000
3025 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3026 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3027 Load Address: 0x00000000
3028 Entry Point: 0x00000000
3030 NOTE: for embedded systems where boot time is critical you can trade
3031 speed for memory and install an UNCOMPRESSED image instead: this
3032 needs more space in Flash, but boots much faster since it does not
3033 need to be uncompressed:
3035 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3036 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3037 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3038 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3039 > examples/uImage.TQM850L-uncompressed
3040 Image Name: 2.4.4 kernel for TQM850L
3041 Created: Wed Jul 19 02:34:59 2000
3042 Image Type: PowerPC Linux Kernel Image (uncompressed)
3043 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3044 Load Address: 0x00000000
3045 Entry Point: 0x00000000
3048 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3049 when your kernel is intended to use an initial ramdisk:
3051 -> tools/mkimage -n 'Simple Ramdisk Image' \
3052 > -A ppc -O linux -T ramdisk -C gzip \
3053 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3054 Image Name: Simple Ramdisk Image
3055 Created: Wed Jan 12 14:01:50 2000
3056 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3057 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3058 Load Address: 0x00000000
3059 Entry Point: 0x00000000
3062 Installing a Linux Image:
3063 -------------------------
3065 To downloading a U-Boot image over the serial (console) interface,
3066 you must convert the image to S-Record format:
3068 objcopy -I binary -O srec examples/image examples/image.srec
3070 The 'objcopy' does not understand the information in the U-Boot
3071 image header, so the resulting S-Record file will be relative to
3072 address 0x00000000. To load it to a given address, you need to
3073 specify the target address as 'offset' parameter with the 'loads'
3076 Example: install the image to address 0x40100000 (which on the
3077 TQM8xxL is in the first Flash bank):
3079 => erase 40100000 401FFFFF
3085 ## Ready for S-Record download ...
3086 ~>examples/image.srec
3087 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3089 15989 15990 15991 15992
3090 [file transfer complete]
3092 ## Start Addr = 0x00000000
3095 You can check the success of the download using the 'iminfo' command;
3096 this includes a checksum verification so you can be sure no data
3097 corruption happened:
3101 ## Checking Image at 40100000 ...
3102 Image Name: 2.2.13 for initrd on TQM850L
3103 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3104 Data Size: 335725 Bytes = 327 kB = 0 MB
3105 Load Address: 00000000
3106 Entry Point: 0000000c
3107 Verifying Checksum ... OK
3113 The "bootm" command is used to boot an application that is stored in
3114 memory (RAM or Flash). In case of a Linux kernel image, the contents
3115 of the "bootargs" environment variable is passed to the kernel as
3116 parameters. You can check and modify this variable using the
3117 "printenv" and "setenv" commands:
3120 => printenv bootargs
3121 bootargs=root=/dev/ram
3123 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3125 => printenv bootargs
3126 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3129 ## Booting Linux kernel at 40020000 ...
3130 Image Name: 2.2.13 for NFS on TQM850L
3131 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3132 Data Size: 381681 Bytes = 372 kB = 0 MB
3133 Load Address: 00000000
3134 Entry Point: 0000000c
3135 Verifying Checksum ... OK
3136 Uncompressing Kernel Image ... OK
3137 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
3138 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3139 time_init: decrementer frequency = 187500000/60
3140 Calibrating delay loop... 49.77 BogoMIPS
3141 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3144 If you want to boot a Linux kernel with initial ram disk, you pass
3145 the memory addresses of both the kernel and the initrd image (PPBCOOT
3146 format!) to the "bootm" command:
3148 => imi 40100000 40200000
3150 ## Checking Image at 40100000 ...
3151 Image Name: 2.2.13 for initrd on TQM850L
3152 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3153 Data Size: 335725 Bytes = 327 kB = 0 MB
3154 Load Address: 00000000
3155 Entry Point: 0000000c
3156 Verifying Checksum ... OK
3158 ## Checking Image at 40200000 ...
3159 Image Name: Simple Ramdisk Image
3160 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3161 Data Size: 566530 Bytes = 553 kB = 0 MB
3162 Load Address: 00000000
3163 Entry Point: 00000000
3164 Verifying Checksum ... OK
3166 => bootm 40100000 40200000
3167 ## Booting Linux kernel at 40100000 ...
3168 Image Name: 2.2.13 for initrd on TQM850L
3169 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3170 Data Size: 335725 Bytes = 327 kB = 0 MB
3171 Load Address: 00000000
3172 Entry Point: 0000000c
3173 Verifying Checksum ... OK
3174 Uncompressing Kernel Image ... OK
3175 ## Loading RAMDisk Image at 40200000 ...
3176 Image Name: Simple Ramdisk Image
3177 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3178 Data Size: 566530 Bytes = 553 kB = 0 MB
3179 Load Address: 00000000
3180 Entry Point: 00000000
3181 Verifying Checksum ... OK
3182 Loading Ramdisk ... OK
3183 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
3184 Boot arguments: root=/dev/ram
3185 time_init: decrementer frequency = 187500000/60
3186 Calibrating delay loop... 49.77 BogoMIPS
3188 RAMDISK: Compressed image found at block 0
3189 VFS: Mounted root (ext2 filesystem).
3193 Boot Linux and pass a flat device tree:
3196 First, U-Boot must be compiled with the appropriate defines. See the section
3197 titled "Linux Kernel Interface" above for a more in depth explanation. The
3198 following is an example of how to start a kernel and pass an updated
3204 oft=oftrees/mpc8540ads.dtb
3205 => tftp $oftaddr $oft
3206 Speed: 1000, full duplex
3208 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3209 Filename 'oftrees/mpc8540ads.dtb'.
3210 Load address: 0x300000
3213 Bytes transferred = 4106 (100a hex)
3214 => tftp $loadaddr $bootfile
3215 Speed: 1000, full duplex
3217 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3219 Load address: 0x200000
3220 Loading:############
3222 Bytes transferred = 1029407 (fb51f hex)
3227 => bootm $loadaddr - $oftaddr
3228 ## Booting image at 00200000 ...
3229 Image Name: Linux-2.6.17-dirty
3230 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3231 Data Size: 1029343 Bytes = 1005.2 kB
3232 Load Address: 00000000
3233 Entry Point: 00000000
3234 Verifying Checksum ... OK
3235 Uncompressing Kernel Image ... OK
3236 Booting using flat device tree at 0x300000
3237 Using MPC85xx ADS machine description
3238 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3242 More About U-Boot Image Types:
3243 ------------------------------
3245 U-Boot supports the following image types:
3247 "Standalone Programs" are directly runnable in the environment
3248 provided by U-Boot; it is expected that (if they behave
3249 well) you can continue to work in U-Boot after return from
3250 the Standalone Program.
3251 "OS Kernel Images" are usually images of some Embedded OS which
3252 will take over control completely. Usually these programs
3253 will install their own set of exception handlers, device
3254 drivers, set up the MMU, etc. - this means, that you cannot
3255 expect to re-enter U-Boot except by resetting the CPU.
3256 "RAMDisk Images" are more or less just data blocks, and their
3257 parameters (address, size) are passed to an OS kernel that is
3259 "Multi-File Images" contain several images, typically an OS
3260 (Linux) kernel image and one or more data images like
3261 RAMDisks. This construct is useful for instance when you want
3262 to boot over the network using BOOTP etc., where the boot
3263 server provides just a single image file, but you want to get
3264 for instance an OS kernel and a RAMDisk image.
3266 "Multi-File Images" start with a list of image sizes, each
3267 image size (in bytes) specified by an "uint32_t" in network
3268 byte order. This list is terminated by an "(uint32_t)0".
3269 Immediately after the terminating 0 follow the images, one by
3270 one, all aligned on "uint32_t" boundaries (size rounded up to
3271 a multiple of 4 bytes).
3273 "Firmware Images" are binary images containing firmware (like
3274 U-Boot or FPGA images) which usually will be programmed to
3277 "Script files" are command sequences that will be executed by
3278 U-Boot's command interpreter; this feature is especially
3279 useful when you configure U-Boot to use a real shell (hush)
3280 as command interpreter.
3286 One of the features of U-Boot is that you can dynamically load and
3287 run "standalone" applications, which can use some resources of
3288 U-Boot like console I/O functions or interrupt services.
3290 Two simple examples are included with the sources:
3295 'examples/hello_world.c' contains a small "Hello World" Demo
3296 application; it is automatically compiled when you build U-Boot.
3297 It's configured to run at address 0x00040004, so you can play with it
3301 ## Ready for S-Record download ...
3302 ~>examples/hello_world.srec
3303 1 2 3 4 5 6 7 8 9 10 11 ...
3304 [file transfer complete]
3306 ## Start Addr = 0x00040004
3308 => go 40004 Hello World! This is a test.
3309 ## Starting application at 0x00040004 ...
3320 Hit any key to exit ...
3322 ## Application terminated, rc = 0x0
3324 Another example, which demonstrates how to register a CPM interrupt
3325 handler with the U-Boot code, can be found in 'examples/timer.c'.
3326 Here, a CPM timer is set up to generate an interrupt every second.
3327 The interrupt service routine is trivial, just printing a '.'
3328 character, but this is just a demo program. The application can be
3329 controlled by the following keys:
3331 ? - print current values og the CPM Timer registers
3332 b - enable interrupts and start timer
3333 e - stop timer and disable interrupts
3334 q - quit application
3337 ## Ready for S-Record download ...
3338 ~>examples/timer.srec
3339 1 2 3 4 5 6 7 8 9 10 11 ...
3340 [file transfer complete]
3342 ## Start Addr = 0x00040004
3345 ## Starting application at 0x00040004 ...
3348 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3351 [q, b, e, ?] Set interval 1000000 us
3354 [q, b, e, ?] ........
3355 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3358 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3361 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3364 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3366 [q, b, e, ?] ...Stopping timer
3368 [q, b, e, ?] ## Application terminated, rc = 0x0
3374 Over time, many people have reported problems when trying to use the
3375 "minicom" terminal emulation program for serial download. I (wd)
3376 consider minicom to be broken, and recommend not to use it. Under
3377 Unix, I recommend to use C-Kermit for general purpose use (and
3378 especially for kermit binary protocol download ("loadb" command), and
3379 use "cu" for S-Record download ("loads" command).
3381 Nevertheless, if you absolutely want to use it try adding this
3382 configuration to your "File transfer protocols" section:
3384 Name Program Name U/D FullScr IO-Red. Multi
3385 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3386 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3392 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3393 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3395 Building requires a cross environment; it is known to work on
3396 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3397 need gmake since the Makefiles are not compatible with BSD make).
3398 Note that the cross-powerpc package does not install include files;
3399 attempting to build U-Boot will fail because <machine/ansi.h> is
3400 missing. This file has to be installed and patched manually:
3402 # cd /usr/pkg/cross/powerpc-netbsd/include
3404 # ln -s powerpc machine
3405 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3406 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3408 Native builds *don't* work due to incompatibilities between native
3409 and U-Boot include files.
3411 Booting assumes that (the first part of) the image booted is a
3412 stage-2 loader which in turn loads and then invokes the kernel
3413 proper. Loader sources will eventually appear in the NetBSD source
3414 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3415 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3418 Implementation Internals:
3419 =========================
3421 The following is not intended to be a complete description of every
3422 implementation detail. However, it should help to understand the
3423 inner workings of U-Boot and make it easier to port it to custom
3427 Initial Stack, Global Data:
3428 ---------------------------
3430 The implementation of U-Boot is complicated by the fact that U-Boot
3431 starts running out of ROM (flash memory), usually without access to
3432 system RAM (because the memory controller is not initialized yet).
3433 This means that we don't have writable Data or BSS segments, and BSS
3434 is not initialized as zero. To be able to get a C environment working
3435 at all, we have to allocate at least a minimal stack. Implementation
3436 options for this are defined and restricted by the CPU used: Some CPU
3437 models provide on-chip memory (like the IMMR area on MPC8xx and
3438 MPC826x processors), on others (parts of) the data cache can be
3439 locked as (mis-) used as memory, etc.
3441 Chris Hallinan posted a good summary of these issues to the
3442 u-boot-users mailing list:
3444 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3445 From: "Chris Hallinan" <clh@net1plus.com>
3446 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3449 Correct me if I'm wrong, folks, but the way I understand it
3450 is this: Using DCACHE as initial RAM for Stack, etc, does not
3451 require any physical RAM backing up the cache. The cleverness
3452 is that the cache is being used as a temporary supply of
3453 necessary storage before the SDRAM controller is setup. It's
3454 beyond the scope of this list to expain the details, but you
3455 can see how this works by studying the cache architecture and
3456 operation in the architecture and processor-specific manuals.
3458 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3459 is another option for the system designer to use as an
3460 initial stack/ram area prior to SDRAM being available. Either
3461 option should work for you. Using CS 4 should be fine if your
3462 board designers haven't used it for something that would
3463 cause you grief during the initial boot! It is frequently not
3466 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3467 with your processor/board/system design. The default value
3468 you will find in any recent u-boot distribution in
3469 walnut.h should work for you. I'd set it to a value larger
3470 than your SDRAM module. If you have a 64MB SDRAM module, set
3471 it above 400_0000. Just make sure your board has no resources
3472 that are supposed to respond to that address! That code in
3473 start.S has been around a while and should work as is when
3474 you get the config right.
3479 It is essential to remember this, since it has some impact on the C
3480 code for the initialization procedures:
3482 * Initialized global data (data segment) is read-only. Do not attempt
3485 * Do not use any unitialized global data (or implicitely initialized
3486 as zero data - BSS segment) at all - this is undefined, initiali-
3487 zation is performed later (when relocating to RAM).
3489 * Stack space is very limited. Avoid big data buffers or things like
3492 Having only the stack as writable memory limits means we cannot use
3493 normal global data to share information beween the code. But it
3494 turned out that the implementation of U-Boot can be greatly
3495 simplified by making a global data structure (gd_t) available to all
3496 functions. We could pass a pointer to this data as argument to _all_
3497 functions, but this would bloat the code. Instead we use a feature of
3498 the GCC compiler (Global Register Variables) to share the data: we
3499 place a pointer (gd) to the global data into a register which we
3500 reserve for this purpose.
3502 When choosing a register for such a purpose we are restricted by the
3503 relevant (E)ABI specifications for the current architecture, and by
3504 GCC's implementation.
3506 For PowerPC, the following registers have specific use:
3508 R2: reserved for system use
3509 R3-R4: parameter passing and return values
3510 R5-R10: parameter passing
3511 R13: small data area pointer
3515 (U-Boot also uses R14 as internal GOT pointer.)
3517 ==> U-Boot will use R2 to hold a pointer to the global data
3519 Note: on PPC, we could use a static initializer (since the
3520 address of the global data structure is known at compile time),
3521 but it turned out that reserving a register results in somewhat
3522 smaller code - although the code savings are not that big (on
3523 average for all boards 752 bytes for the whole U-Boot image,
3524 624 text + 127 data).
3526 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3527 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3529 ==> U-Boot will use P5 to hold a pointer to the global data
3531 On ARM, the following registers are used:
3533 R0: function argument word/integer result
3534 R1-R3: function argument word
3536 R10: stack limit (used only if stack checking if enabled)
3537 R11: argument (frame) pointer
3538 R12: temporary workspace
3541 R15: program counter
3543 ==> U-Boot will use R8 to hold a pointer to the global data
3545 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3546 or current versions of GCC may "optimize" the code too much.
3551 U-Boot runs in system state and uses physical addresses, i.e. the
3552 MMU is not used either for address mapping nor for memory protection.
3554 The available memory is mapped to fixed addresses using the memory
3555 controller. In this process, a contiguous block is formed for each
3556 memory type (Flash, SDRAM, SRAM), even when it consists of several
3557 physical memory banks.
3559 U-Boot is installed in the first 128 kB of the first Flash bank (on
3560 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3561 booting and sizing and initializing DRAM, the code relocates itself
3562 to the upper end of DRAM. Immediately below the U-Boot code some
3563 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3564 configuration setting]. Below that, a structure with global Board
3565 Info data is placed, followed by the stack (growing downward).
3567 Additionally, some exception handler code is copied to the low 8 kB
3568 of DRAM (0x00000000 ... 0x00001FFF).
3570 So a typical memory configuration with 16 MB of DRAM could look like
3573 0x0000 0000 Exception Vector code
3576 0x0000 2000 Free for Application Use
3582 0x00FB FF20 Monitor Stack (Growing downward)
3583 0x00FB FFAC Board Info Data and permanent copy of global data
3584 0x00FC 0000 Malloc Arena
3587 0x00FE 0000 RAM Copy of Monitor Code
3588 ... eventually: LCD or video framebuffer
3589 ... eventually: pRAM (Protected RAM - unchanged by reset)
3590 0x00FF FFFF [End of RAM]
3593 System Initialization:
3594 ----------------------
3596 In the reset configuration, U-Boot starts at the reset entry point
3597 (on most PowerPC systens at address 0x00000100). Because of the reset
3598 configuration for CS0# this is a mirror of the onboard Flash memory.
3599 To be able to re-map memory U-Boot then jumps to its link address.
3600 To be able to implement the initialization code in C, a (small!)
3601 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3602 which provide such a feature like MPC8xx or MPC8260), or in a locked
3603 part of the data cache. After that, U-Boot initializes the CPU core,
3604 the caches and the SIU.
3606 Next, all (potentially) available memory banks are mapped using a
3607 preliminary mapping. For example, we put them on 512 MB boundaries
3608 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3609 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3610 programmed for SDRAM access. Using the temporary configuration, a
3611 simple memory test is run that determines the size of the SDRAM
3614 When there is more than one SDRAM bank, and the banks are of
3615 different size, the largest is mapped first. For equal size, the first
3616 bank (CS2#) is mapped first. The first mapping is always for address
3617 0x00000000, with any additional banks following immediately to create
3618 contiguous memory starting from 0.
3620 Then, the monitor installs itself at the upper end of the SDRAM area
3621 and allocates memory for use by malloc() and for the global Board
3622 Info data; also, the exception vector code is copied to the low RAM
3623 pages, and the final stack is set up.
3625 Only after this relocation will you have a "normal" C environment;
3626 until that you are restricted in several ways, mostly because you are
3627 running from ROM, and because the code will have to be relocated to a
3631 U-Boot Porting Guide:
3632 ----------------------
3634 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3638 int main (int argc, char *argv[])
3640 sighandler_t no_more_time;
3642 signal (SIGALRM, no_more_time);
3643 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3645 if (available_money > available_manpower) {
3646 pay consultant to port U-Boot;
3650 Download latest U-Boot source;
3652 Subscribe to u-boot-users mailing list;
3655 email ("Hi, I am new to U-Boot, how do I get started?");
3659 Read the README file in the top level directory;
3660 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3661 Read the source, Luke;
3664 if (available_money > toLocalCurrency ($2500)) {
3667 Add a lot of aggravation and time;
3670 Create your own board support subdirectory;
3672 Create your own board config file;
3676 Add / modify source code;
3680 email ("Hi, I am having problems...");
3682 Send patch file to Wolfgang;
3687 void no_more_time (int sig)
3696 All contributions to U-Boot should conform to the Linux kernel
3697 coding style; see the file "Documentation/CodingStyle" and the script
3698 "scripts/Lindent" in your Linux kernel source directory. In sources
3699 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3700 spaces before parameters to function calls) is actually used.
3702 Source files originating from a different project (for example the
3703 MTD subsystem) are generally exempt from these guidelines and are not
3704 reformated to ease subsequent migration to newer versions of those
3707 Please note that U-Boot is implemented in C (and to some small parts in
3708 Assembler); no C++ is used, so please do not use C++ style comments (//)
3711 Please also stick to the following formatting rules:
3712 - remove any trailing white space
3713 - use TAB characters for indentation, not spaces
3714 - make sure NOT to use DOS '\r\n' line feeds
3715 - do not add more than 2 empty lines to source files
3716 - do not add trailing empty lines to source files
3718 Submissions which do not conform to the standards may be returned
3719 with a request to reformat the changes.
3725 Since the number of patches for U-Boot is growing, we need to
3726 establish some rules. Submissions which do not conform to these rules
3727 may be rejected, even when they contain important and valuable stuff.
3729 Patches shall be sent to the u-boot-users mailing list.
3731 When you send a patch, please include the following information with
3734 * For bug fixes: a description of the bug and how your patch fixes
3735 this bug. Please try to include a way of demonstrating that the
3736 patch actually fixes something.
3738 * For new features: a description of the feature and your
3741 * A CHANGELOG entry as plaintext (separate from the patch)
3743 * For major contributions, your entry to the CREDITS file
3745 * When you add support for a new board, don't forget to add this
3746 board to the MAKEALL script, too.
3748 * If your patch adds new configuration options, don't forget to
3749 document these in the README file.
3751 * The patch itself. If you are accessing the CVS repository use "cvs
3752 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3753 version of diff does not support these options, then get the latest
3754 version of GNU diff.
3756 The current directory when running this command shall be the top
3757 level directory of the U-Boot source tree, or it's parent directory
3758 (i. e. please make sure that your patch includes sufficient
3759 directory information for the affected files).
3761 We accept patches as plain text, MIME attachments or as uuencoded
3764 * If one logical set of modifications affects or creates several
3765 files, all these changes shall be submitted in a SINGLE patch file.
3767 * Changesets that contain different, unrelated modifications shall be
3768 submitted as SEPARATE patches, one patch per changeset.
3773 * Before sending the patch, run the MAKEALL script on your patched
3774 source tree and make sure that no errors or warnings are reported
3775 for any of the boards.
3777 * Keep your modifications to the necessary minimum: A patch
3778 containing several unrelated changes or arbitrary reformats will be
3779 returned with a request to re-formatting / split it.
3781 * If you modify existing code, make sure that your new code does not
3782 add to the memory footprint of the code ;-) Small is beautiful!
3783 When adding new features, these should compile conditionally only
3784 (using #ifdef), and the resulting code with the new feature
3785 disabled must not need more memory than the old code without your
3788 * Remember that there is a size limit of 40 kB per message on the
3789 u-boot-users mailing list. Compression may help.
projects / karo-tx-uboot.git / blob