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 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - libfdt Library files to support flattened device trees
168 - net Networking code
169 - post Power On Self Test
170 - rtc Real Time Clock drivers
171 - tools Tools to build S-Record or U-Boot images, etc.
173 Software Configuration:
174 =======================
176 Configuration is usually done using C preprocessor defines; the
177 rationale behind that is to avoid dead code whenever possible.
179 There are two classes of configuration variables:
181 * Configuration _OPTIONS_:
182 These are selectable by the user and have names beginning with
185 * Configuration _SETTINGS_:
186 These depend on the hardware etc. and should not be meddled with if
187 you don't know what you're doing; they have names beginning with
190 Later we will add a configuration tool - probably similar to or even
191 identical to what's used for the Linux kernel. Right now, we have to
192 do the configuration by hand, which means creating some symbolic
193 links and editing some configuration files. We use the TQM8xxL boards
197 Selection of Processor Architecture and Board Type:
198 ---------------------------------------------------
200 For all supported boards there are ready-to-use default
201 configurations available; just type "make <board_name>_config".
203 Example: For a TQM823L module type:
208 For the Cogent platform, you need to specify the cpu type as well;
209 e.g. "make cogent_mpc8xx_config". And also configure the cogent
210 directory according to the instructions in cogent/README.
213 Configuration Options:
214 ----------------------
216 Configuration depends on the combination of board and CPU type; all
217 such information is kept in a configuration file
218 "include/configs/<board_name>.h".
220 Example: For a TQM823L module, all configuration settings are in
221 "include/configs/TQM823L.h".
224 Many of the options are named exactly as the corresponding Linux
225 kernel configuration options. The intention is to make it easier to
226 build a config tool - later.
229 The following options need to be configured:
231 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
233 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
235 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
236 Define exactly one of
240 - CPU Module Type: (if CONFIG_COGENT is defined)
241 Define exactly one of
243 --- FIXME --- not tested yet:
244 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
245 CONFIG_CMA287_23, CONFIG_CMA287_50
247 - Motherboard Type: (if CONFIG_COGENT is defined)
248 Define exactly one of
249 CONFIG_CMA101, CONFIG_CMA102
251 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
252 Define one or more of
255 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
256 Define one or more of
257 CONFIG_LCD_HEARTBEAT - update a character position on
258 the lcd display every second with
261 - Board flavour: (if CONFIG_MPC8260ADS is defined)
264 CFG_8260ADS - original MPC8260ADS
265 CFG_8266ADS - MPC8266ADS
266 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
267 CFG_8272ADS - MPC8272ADS
269 - MPC824X Family Member (if CONFIG_MPC824X is defined)
270 Define exactly one of
271 CONFIG_MPC8240, CONFIG_MPC8245
273 - 8xx CPU Options: (if using an MPC8xx cpu)
274 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
275 get_gclk_freq() cannot work
276 e.g. if there is no 32KHz
277 reference PIT/RTC clock
278 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
281 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
284 CONFIG_8xx_CPUCLK_DEFAULT
285 See doc/README.MPC866
289 Define this to measure the actual CPU clock instead
290 of relying on the correctness of the configured
291 values. Mostly useful for board bringup to make sure
292 the PLL is locked at the intended frequency. Note
293 that this requires a (stable) reference clock (32 kHz
294 RTC clock or CFG_8XX_XIN)
296 - Intel Monahans options:
297 CFG_MONAHANS_RUN_MODE_OSC_RATIO
299 Defines the Monahans run mode to oscillator
300 ratio. Valid values are 8, 16, 24, 31. The core
301 frequency is this value multiplied by 13 MHz.
303 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
305 Defines the Monahans turbo mode to oscillator
306 ratio. Valid values are 1 (default if undefined) and
307 2. The core frequency as calculated above is multiplied
310 - Linux Kernel Interface:
313 U-Boot stores all clock information in Hz
314 internally. For binary compatibility with older Linux
315 kernels (which expect the clocks passed in the
316 bd_info data to be in MHz) the environment variable
317 "clocks_in_mhz" can be defined so that U-Boot
318 converts clock data to MHZ before passing it to the
320 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
321 "clocks_in_mhz=1" is automatically included in the
324 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
326 When transfering memsize parameter to linux, some versions
327 expect it to be in bytes, others in MB.
328 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
330 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
332 New kernel versions are expecting firmware settings to be
333 passed using flattened device trees (based on open firmware
337 * New libfdt-based support
338 * Adds the "fdt" command
339 * The bootm command does _not_ modify the fdt
342 * Deprecated, see CONFIG_OF_LIBFDT
343 * Original ft_build.c-based support
344 * Automatically modifies the dft as part of the bootm command
345 * The environment variable "disable_of", when set,
346 disables this functionality.
348 CONFIG_OF_FLAT_TREE_MAX_SIZE
350 The maximum size of the constructed OF tree.
352 OF_CPU - The proper name of the cpus node.
353 OF_SOC - The proper name of the soc node.
354 OF_TBCLK - The timebase frequency.
355 OF_STDOUT_PATH - The path to the console device
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 bd_t" command
367 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
368 will have a copy of u-boot's environment variables
370 CONFIG_OF_BOARD_SETUP
372 Board code has addition modification that it wants to make
373 to the flat device tree before handing it off to the kernel
377 This define fills in the correct boot cpu in the boot
378 param header, the default value is zero if undefined.
383 Define this if you want support for Amba PrimeCell PL010 UARTs.
387 Define this if you want support for Amba PrimeCell PL011 UARTs.
391 If you have Amba PrimeCell PL011 UARTs, set this variable to
392 the clock speed of the UARTs.
396 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
397 define this to a list of base addresses for each (supported)
398 port. See e.g. include/configs/versatile.h
402 Depending on board, define exactly one serial port
403 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
404 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
405 console by defining CONFIG_8xx_CONS_NONE
407 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
408 port routines must be defined elsewhere
409 (i.e. serial_init(), serial_getc(), ...)
412 Enables console device for a color framebuffer. Needs following
413 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
414 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
416 VIDEO_HW_RECTFILL graphic chip supports
419 VIDEO_HW_BITBLT graphic chip supports
420 bit-blit (cf. smiLynxEM)
421 VIDEO_VISIBLE_COLS visible pixel columns
423 VIDEO_VISIBLE_ROWS visible pixel rows
424 VIDEO_PIXEL_SIZE bytes per pixel
425 VIDEO_DATA_FORMAT graphic data format
426 (0-5, cf. cfb_console.c)
427 VIDEO_FB_ADRS framebuffer address
428 VIDEO_KBD_INIT_FCT keyboard int fct
429 (i.e. i8042_kbd_init())
430 VIDEO_TSTC_FCT test char fct
432 VIDEO_GETC_FCT get char fct
434 CONFIG_CONSOLE_CURSOR cursor drawing on/off
435 (requires blink timer
437 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
438 CONFIG_CONSOLE_TIME display time/date info in
440 (requires CONFIG_CMD_DATE)
441 CONFIG_VIDEO_LOGO display Linux logo in
443 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
444 linux_logo.h for logo.
445 Requires CONFIG_VIDEO_LOGO
446 CONFIG_CONSOLE_EXTRA_INFO
447 addional board info beside
450 When CONFIG_CFB_CONSOLE is defined, video console is
451 default i/o. Serial console can be forced with
452 environment 'console=serial'.
454 When CONFIG_SILENT_CONSOLE is defined, all console
455 messages (by U-Boot and Linux!) can be silenced with
456 the "silent" environment variable. See
457 doc/README.silent for more information.
460 CONFIG_BAUDRATE - in bps
461 Select one of the baudrates listed in
462 CFG_BAUDRATE_TABLE, see below.
463 CFG_BRGCLK_PRESCALE, baudrate prescale
465 - Interrupt driven serial port input:
466 CONFIG_SERIAL_SOFTWARE_FIFO
469 Use an interrupt handler for receiving data on the
470 serial port. It also enables using hardware handshake
471 (RTS/CTS) and UART's built-in FIFO. Set the number of
472 bytes the interrupt driven input buffer should have.
474 Leave undefined to disable this feature, including
475 disable the buffer and hardware handshake.
477 - Console UART Number:
481 If defined internal UART1 (and not UART0) is used
482 as default U-Boot console.
484 - Boot Delay: CONFIG_BOOTDELAY - in seconds
485 Delay before automatically booting the default image;
486 set to -1 to disable autoboot.
488 See doc/README.autoboot for these options that
489 work with CONFIG_BOOTDELAY. None are required.
490 CONFIG_BOOT_RETRY_TIME
491 CONFIG_BOOT_RETRY_MIN
492 CONFIG_AUTOBOOT_KEYED
493 CONFIG_AUTOBOOT_PROMPT
494 CONFIG_AUTOBOOT_DELAY_STR
495 CONFIG_AUTOBOOT_STOP_STR
496 CONFIG_AUTOBOOT_DELAY_STR2
497 CONFIG_AUTOBOOT_STOP_STR2
498 CONFIG_ZERO_BOOTDELAY_CHECK
499 CONFIG_RESET_TO_RETRY
503 Only needed when CONFIG_BOOTDELAY is enabled;
504 define a command string that is automatically executed
505 when no character is read on the console interface
506 within "Boot Delay" after reset.
509 This can be used to pass arguments to the bootm
510 command. The value of CONFIG_BOOTARGS goes into the
511 environment value "bootargs".
513 CONFIG_RAMBOOT and CONFIG_NFSBOOT
514 The value of these goes into the environment as
515 "ramboot" and "nfsboot" respectively, and can be used
516 as a convenience, when switching between booting from
522 When this option is #defined, the existence of the
523 environment variable "preboot" will be checked
524 immediately before starting the CONFIG_BOOTDELAY
525 countdown and/or running the auto-boot command resp.
526 entering interactive mode.
528 This feature is especially useful when "preboot" is
529 automatically generated or modified. For an example
530 see the LWMON board specific code: here "preboot" is
531 modified when the user holds down a certain
532 combination of keys on the (special) keyboard when
535 - Serial Download Echo Mode:
537 If defined to 1, all characters received during a
538 serial download (using the "loads" command) are
539 echoed back. This might be needed by some terminal
540 emulations (like "cu"), but may as well just take
541 time on others. This setting #define's the initial
542 value of the "loads_echo" environment variable.
544 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
546 Select one of the baudrates listed in
547 CFG_BAUDRATE_TABLE, see below.
550 Monitor commands can be included or excluded
551 from the build by using the #include files
552 "config_cmd_all.h" and #undef'ing unwanted
553 commands, or using "config_cmd_default.h"
554 and augmenting with additional #define's
557 The default command configuration includes all commands
558 except those marked below with a "*".
560 CONFIG_CMD_ASKENV * ask for env variable
561 CONFIG_CMD_AUTOSCRIPT Autoscript Support
562 CONFIG_CMD_BDI bdinfo
563 CONFIG_CMD_BEDBUG * Include BedBug Debugger
564 CONFIG_CMD_BMP * BMP support
565 CONFIG_CMD_BSP * Board specific commands
566 CONFIG_CMD_BOOTD bootd
567 CONFIG_CMD_CACHE * icache, dcache
568 CONFIG_CMD_CONSOLE coninfo
569 CONFIG_CMD_DATE * support for RTC, date/time...
570 CONFIG_CMD_DHCP * DHCP support
571 CONFIG_CMD_DIAG * Diagnostics
572 CONFIG_CMD_DOC * Disk-On-Chip Support
573 CONFIG_CMD_DTT * Digital Therm and Thermostat
574 CONFIG_CMD_ECHO echo arguments
575 CONFIG_CMD_EEPROM * EEPROM read/write support
576 CONFIG_CMD_ELF * bootelf, bootvx
577 CONFIG_CMD_ENV saveenv
578 CONFIG_CMD_FDC * Floppy Disk Support
579 CONFIG_CMD_FAT * FAT partition support
580 CONFIG_CMD_FDOS * Dos diskette Support
581 CONFIG_CMD_FLASH flinfo, erase, protect
582 CONFIG_CMD_FPGA FPGA device initialization support
583 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
584 CONFIG_CMD_I2C * I2C serial bus support
585 CONFIG_CMD_IDE * IDE harddisk support
586 CONFIG_CMD_IMI iminfo
587 CONFIG_CMD_IMLS List all found images
588 CONFIG_CMD_IMMAP * IMMR dump support
589 CONFIG_CMD_IRQ * irqinfo
590 CONFIG_CMD_ITEST Integer/string test of 2 values
591 CONFIG_CMD_JFFS2 * JFFS2 Support
592 CONFIG_CMD_KGDB * kgdb
593 CONFIG_CMD_LOADB loadb
594 CONFIG_CMD_LOADS loads
595 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
597 CONFIG_CMD_MISC Misc functions like sleep etc
598 CONFIG_CMD_MMC * MMC memory mapped support
599 CONFIG_CMD_MII * MII utility commands
600 CONFIG_CMD_NAND * NAND support
601 CONFIG_CMD_NET bootp, tftpboot, rarpboot
602 CONFIG_CMD_PCI * pciinfo
603 CONFIG_CMD_PCMCIA * PCMCIA support
604 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
606 CONFIG_CMD_PORTIO * Port I/O
607 CONFIG_CMD_REGINFO * Register dump
608 CONFIG_CMD_RUN run command in env variable
609 CONFIG_CMD_SAVES * save S record dump
610 CONFIG_CMD_SCSI * SCSI Support
611 CONFIG_CMD_SDRAM * print SDRAM configuration information
612 (requires CONFIG_CMD_I2C)
613 CONFIG_CMD_SETGETDCR Support for DCR Register access
615 CONFIG_CMD_SPI * SPI serial bus support
616 CONFIG_CMD_USB * USB support
617 CONFIG_CMD_VFD * VFD support (TRAB)
618 CONFIG_CMD_BSP * Board SPecific functions
619 CONFIG_CMD_CDP * Cisco Discover Protocol support
620 CONFIG_CMD_FSL * Microblaze FSL support
623 EXAMPLE: If you want all functions except of network
624 support you can write:
626 #include "config_cmd_all.h"
627 #undef CONFIG_CMD_NET
630 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
632 Note: Don't enable the "icache" and "dcache" commands
633 (configuration option CONFIG_CMD_CACHE) unless you know
634 what you (and your U-Boot users) are doing. Data
635 cache cannot be enabled on systems like the 8xx or
636 8260 (where accesses to the IMMR region must be
637 uncached), and it cannot be disabled on all other
638 systems where we (mis-) use the data cache to hold an
639 initial stack and some data.
642 XXX - this list needs to get updated!
646 If this variable is defined, it enables watchdog
647 support. There must be support in the platform specific
648 code for a watchdog. For the 8xx and 8260 CPUs, the
649 SIU Watchdog feature is enabled in the SYPCR
653 CONFIG_VERSION_VARIABLE
654 If this variable is defined, an environment variable
655 named "ver" is created by U-Boot showing the U-Boot
656 version as printed by the "version" command.
657 This variable is readonly.
661 When CONFIG_CMD_DATE is selected, the type of the RTC
662 has to be selected, too. Define exactly one of the
665 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
666 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
667 CONFIG_RTC_MC146818 - use MC146818 RTC
668 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
669 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
670 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
671 CONFIG_RTC_DS164x - use Dallas DS164x RTC
672 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
674 Note that if the RTC uses I2C, then the I2C interface
675 must also be configured. See I2C Support, below.
679 When CONFIG_TIMESTAMP is selected, the timestamp
680 (date and time) of an image is printed by image
681 commands like bootm or iminfo. This option is
682 automatically enabled when you select CONFIG_CMD_DATE .
685 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
686 and/or CONFIG_ISO_PARTITION
688 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
689 CONFIG_CMD_SCSI) you must configure support for at least
690 one partition type as well.
693 CONFIG_IDE_RESET_ROUTINE - this is defined in several
694 board configurations files but used nowhere!
696 CONFIG_IDE_RESET - is this is defined, IDE Reset will
697 be performed by calling the function
698 ide_set_reset(int reset)
699 which has to be defined in a board specific file
704 Set this to enable ATAPI support.
709 Set this to enable support for disks larger than 137GB
710 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
711 Whithout these , LBA48 support uses 32bit variables and will 'only'
712 support disks up to 2.1TB.
715 When enabled, makes the IDE subsystem use 64bit sector addresses.
719 At the moment only there is only support for the
720 SYM53C8XX SCSI controller; define
721 CONFIG_SCSI_SYM53C8XX to enable it.
723 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
724 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
725 CFG_SCSI_MAX_LUN] can be adjusted to define the
726 maximum numbers of LUNs, SCSI ID's and target
728 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
730 - NETWORK Support (PCI):
732 Support for Intel 8254x gigabit chips.
735 Support for Intel 82557/82559/82559ER chips.
736 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
737 write routine for first time initialisation.
740 Support for Digital 2114x chips.
741 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
742 modem chip initialisation (KS8761/QS6611).
745 Support for National dp83815 chips.
748 Support for National dp8382[01] gigabit chips.
750 - NETWORK Support (other):
752 CONFIG_DRIVER_LAN91C96
753 Support for SMSC's LAN91C96 chips.
756 Define this to hold the physical address
757 of the LAN91C96's I/O space
759 CONFIG_LAN91C96_USE_32_BIT
760 Define this to enable 32 bit addressing
762 CONFIG_DRIVER_SMC91111
763 Support for SMSC's LAN91C111 chip
766 Define this to hold the physical address
767 of the device (I/O space)
769 CONFIG_SMC_USE_32_BIT
770 Define this if data bus is 32 bits
772 CONFIG_SMC_USE_IOFUNCS
773 Define this to use i/o functions instead of macros
774 (some hardware wont work with macros)
777 At the moment only the UHCI host controller is
778 supported (PIP405, MIP405, MPC5200); define
779 CONFIG_USB_UHCI to enable it.
780 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
781 and define CONFIG_USB_STORAGE to enable the USB
784 Supported are USB Keyboards and USB Floppy drives
786 MPC5200 USB requires additional defines:
788 for 528 MHz Clock: 0x0001bbbb
790 for differential drivers: 0x00001000
791 for single ended drivers: 0x00005000
793 May be defined to allow interrupt polling
794 instead of using asynchronous interrupts
797 Define the below if you wish to use the USB console.
798 Once firmware is rebuilt from a serial console issue the
799 command "setenv stdin usbtty; setenv stdout usbtty" and
800 attach your usb cable. The Unix command "dmesg" should print
801 it has found a new device. The environment variable usbtty
802 can be set to gserial or cdc_acm to enable your device to
803 appear to a USB host as a Linux gserial device or a
804 Common Device Class Abstract Control Model serial device.
805 If you select usbtty = gserial you should be able to enumerate
807 # modprobe usbserial vendor=0xVendorID product=0xProductID
808 else if using cdc_acm, simply setting the environment
809 variable usbtty to be cdc_acm should suffice. The following
810 might be defined in YourBoardName.h
813 Define this to build a UDC device
816 Define this to have a tty type of device available to
817 talk to the UDC device
819 CFG_CONSOLE_IS_IN_ENV
820 Define this if you want stdin, stdout &/or stderr to
824 CFG_USB_EXTC_CLK 0xBLAH
825 Derive USB clock from external clock "blah"
826 - CFG_USB_EXTC_CLK 0x02
828 CFG_USB_BRG_CLK 0xBLAH
829 Derive USB clock from brgclk
830 - CFG_USB_BRG_CLK 0x04
832 If you have a USB-IF assigned VendorID then you may wish to
833 define your own vendor specific values either in BoardName.h
834 or directly in usbd_vendor_info.h. If you don't define
835 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
836 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
837 should pretend to be a Linux device to it's target host.
839 CONFIG_USBD_MANUFACTURER
840 Define this string as the name of your company for
841 - CONFIG_USBD_MANUFACTURER "my company"
843 CONFIG_USBD_PRODUCT_NAME
844 Define this string as the name of your product
845 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
848 Define this as your assigned Vendor ID from the USB
849 Implementors Forum. This *must* be a genuine Vendor ID
850 to avoid polluting the USB namespace.
851 - CONFIG_USBD_VENDORID 0xFFFF
853 CONFIG_USBD_PRODUCTID
854 Define this as the unique Product ID
856 - CONFIG_USBD_PRODUCTID 0xFFFF
860 The MMC controller on the Intel PXA is supported. To
861 enable this define CONFIG_MMC. The MMC can be
862 accessed from the boot prompt by mapping the device
863 to physical memory similar to flash. Command line is
864 enabled with CONFIG_CMD_MMC. The MMC driver also works with
865 the FAT fs. This is enabled with CONFIG_CMD_FAT.
867 - Journaling Flash filesystem support:
868 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
869 CONFIG_JFFS2_NAND_DEV
870 Define these for a default partition on a NAND device
872 CFG_JFFS2_FIRST_SECTOR,
873 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
874 Define these for a default partition on a NOR device
877 Define this to create an own partition. You have to provide a
878 function struct part_info* jffs2_part_info(int part_num)
880 If you define only one JFFS2 partition you may also want to
881 #define CFG_JFFS_SINGLE_PART 1
882 to disable the command chpart. This is the default when you
883 have not defined a custom partition
888 Define this to enable standard (PC-Style) keyboard
892 Standard PC keyboard driver with US (is default) and
893 GERMAN key layout (switch via environment 'keymap=de') support.
894 Export function i8042_kbd_init, i8042_tstc and i8042_getc
895 for cfb_console. Supports cursor blinking.
900 Define this to enable video support (for output to
905 Enable Chips & Technologies 69000 Video chip
907 CONFIG_VIDEO_SMI_LYNXEM
908 Enable Silicon Motion SMI 712/710/810 Video chip. The
909 video output is selected via environment 'videoout'
910 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
913 For the CT69000 and SMI_LYNXEM drivers, videomode is
914 selected via environment 'videomode'. Two diferent ways
916 - "videomode=num" 'num' is a standard LiLo mode numbers.
917 Following standard modes are supported (* is default):
919 Colors 640x480 800x600 1024x768 1152x864 1280x1024
920 -------------+---------------------------------------------
921 8 bits | 0x301* 0x303 0x305 0x161 0x307
922 15 bits | 0x310 0x313 0x316 0x162 0x319
923 16 bits | 0x311 0x314 0x317 0x163 0x31A
924 24 bits | 0x312 0x315 0x318 ? 0x31B
925 -------------+---------------------------------------------
926 (i.e. setenv videomode 317; saveenv; reset;)
928 - "videomode=bootargs" all the video parameters are parsed
929 from the bootargs. (See drivers/videomodes.c)
932 CONFIG_VIDEO_SED13806
933 Enable Epson SED13806 driver. This driver supports 8bpp
934 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
935 or CONFIG_VIDEO_SED13806_16BPP
940 Define this to enable a custom keyboard support.
941 This simply calls drv_keyboard_init() which must be
942 defined in your board-specific files.
943 The only board using this so far is RBC823.
945 - LCD Support: CONFIG_LCD
947 Define this to enable LCD support (for output to LCD
948 display); also select one of the supported displays
949 by defining one of these:
951 CONFIG_NEC_NL6448AC33:
953 NEC NL6448AC33-18. Active, color, single scan.
955 CONFIG_NEC_NL6448BC20
957 NEC NL6448BC20-08. 6.5", 640x480.
958 Active, color, single scan.
960 CONFIG_NEC_NL6448BC33_54
962 NEC NL6448BC33-54. 10.4", 640x480.
963 Active, color, single scan.
967 Sharp 320x240. Active, color, single scan.
968 It isn't 16x9, and I am not sure what it is.
970 CONFIG_SHARP_LQ64D341
972 Sharp LQ64D341 display, 640x480.
973 Active, color, single scan.
977 HLD1045 display, 640x480.
978 Active, color, single scan.
982 Optrex CBL50840-2 NF-FW 99 22 M5
984 Hitachi LMG6912RPFC-00T
988 320x240. Black & white.
990 Normally display is black on white background; define
991 CFG_WHITE_ON_BLACK to get it inverted.
993 - Splash Screen Support: CONFIG_SPLASH_SCREEN
995 If this option is set, the environment is checked for
996 a variable "splashimage". If found, the usual display
997 of logo, copyright and system information on the LCD
998 is suppressed and the BMP image at the address
999 specified in "splashimage" is loaded instead. The
1000 console is redirected to the "nulldev", too. This
1001 allows for a "silent" boot where a splash screen is
1002 loaded very quickly after power-on.
1004 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1006 If this option is set, additionally to standard BMP
1007 images, gzipped BMP images can be displayed via the
1008 splashscreen support or the bmp command.
1010 - Compression support:
1013 If this option is set, support for bzip2 compressed
1014 images is included. If not, only uncompressed and gzip
1015 compressed images are supported.
1017 NOTE: the bzip2 algorithm requires a lot of RAM, so
1018 the malloc area (as defined by CFG_MALLOC_LEN) should
1024 The address of PHY on MII bus.
1026 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1028 The clock frequency of the MII bus
1032 If this option is set, support for speed/duplex
1033 detection of Gigabit PHY is included.
1035 CONFIG_PHY_RESET_DELAY
1037 Some PHY like Intel LXT971A need extra delay after
1038 reset before any MII register access is possible.
1039 For such PHY, set this option to the usec delay
1040 required. (minimum 300usec for LXT971A)
1042 CONFIG_PHY_CMD_DELAY (ppc4xx)
1044 Some PHY like Intel LXT971A need extra delay after
1045 command issued before MII status register can be read
1052 Define a default value for ethernet address to use
1053 for the respective ethernet interface, in case this
1054 is not determined automatically.
1059 Define a default value for the IP address to use for
1060 the default ethernet interface, in case this is not
1061 determined through e.g. bootp.
1063 - Server IP address:
1066 Defines a default value for theIP address of a TFTP
1067 server to contact when using the "tftboot" command.
1069 - BOOTP Recovery Mode:
1070 CONFIG_BOOTP_RANDOM_DELAY
1072 If you have many targets in a network that try to
1073 boot using BOOTP, you may want to avoid that all
1074 systems send out BOOTP requests at precisely the same
1075 moment (which would happen for instance at recovery
1076 from a power failure, when all systems will try to
1077 boot, thus flooding the BOOTP server. Defining
1078 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1079 inserted before sending out BOOTP requests. The
1080 following delays are inserted then:
1082 1st BOOTP request: delay 0 ... 1 sec
1083 2nd BOOTP request: delay 0 ... 2 sec
1084 3rd BOOTP request: delay 0 ... 4 sec
1086 BOOTP requests: delay 0 ... 8 sec
1088 - DHCP Advanced Options:
1089 You can fine tune the DHCP functionality by defining
1090 CONFIG_BOOTP_* symbols:
1092 CONFIG_BOOTP_SUBNETMASK
1093 CONFIG_BOOTP_GATEWAY
1094 CONFIG_BOOTP_HOSTNAME
1095 CONFIG_BOOTP_NISDOMAIN
1096 CONFIG_BOOTP_BOOTPATH
1097 CONFIG_BOOTP_BOOTFILESIZE
1100 CONFIG_BOOTP_SEND_HOSTNAME
1101 CONFIG_BOOTP_NTPSERVER
1102 CONFIG_BOOTP_TIMEOFFSET
1103 CONFIG_BOOTP_VENDOREX
1105 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1106 environment variable, not the BOOTP server.
1108 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1109 serverip from a DHCP server, it is possible that more
1110 than one DNS serverip is offered to the client.
1111 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1112 serverip will be stored in the additional environment
1113 variable "dnsip2". The first DNS serverip is always
1114 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1117 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1118 to do a dynamic update of a DNS server. To do this, they
1119 need the hostname of the DHCP requester.
1120 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1121 of the "hostname" environment variable is passed as
1122 option 12 to the DHCP server.
1125 CONFIG_CDP_DEVICE_ID
1127 The device id used in CDP trigger frames.
1129 CONFIG_CDP_DEVICE_ID_PREFIX
1131 A two character string which is prefixed to the MAC address
1136 A printf format string which contains the ascii name of
1137 the port. Normally is set to "eth%d" which sets
1138 eth0 for the first ethernet, eth1 for the second etc.
1140 CONFIG_CDP_CAPABILITIES
1142 A 32bit integer which indicates the device capabilities;
1143 0x00000010 for a normal host which does not forwards.
1147 An ascii string containing the version of the software.
1151 An ascii string containing the name of the platform.
1155 A 32bit integer sent on the trigger.
1157 CONFIG_CDP_POWER_CONSUMPTION
1159 A 16bit integer containing the power consumption of the
1160 device in .1 of milliwatts.
1162 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1164 A byte containing the id of the VLAN.
1166 - Status LED: CONFIG_STATUS_LED
1168 Several configurations allow to display the current
1169 status using a LED. For instance, the LED will blink
1170 fast while running U-Boot code, stop blinking as
1171 soon as a reply to a BOOTP request was received, and
1172 start blinking slow once the Linux kernel is running
1173 (supported by a status LED driver in the Linux
1174 kernel). Defining CONFIG_STATUS_LED enables this
1177 - CAN Support: CONFIG_CAN_DRIVER
1179 Defining CONFIG_CAN_DRIVER enables CAN driver support
1180 on those systems that support this (optional)
1181 feature, like the TQM8xxL modules.
1183 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1185 These enable I2C serial bus commands. Defining either of
1186 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1187 include the appropriate I2C driver for the selected cpu.
1189 This will allow you to use i2c commands at the u-boot
1190 command line (as long as you set CONFIG_CMD_I2C in
1191 CONFIG_COMMANDS) and communicate with i2c based realtime
1192 clock chips. See common/cmd_i2c.c for a description of the
1193 command line interface.
1195 CONFIG_I2C_CMD_TREE is a recommended option that places
1196 all I2C commands under a single 'i2c' root command. The
1197 older 'imm', 'imd', 'iprobe' etc. commands are considered
1198 deprecated and may disappear in the future.
1200 CONFIG_HARD_I2C selects a hardware I2C controller.
1202 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1203 bit-banging) driver instead of CPM or similar hardware
1206 There are several other quantities that must also be
1207 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1209 In both cases you will need to define CFG_I2C_SPEED
1210 to be the frequency (in Hz) at which you wish your i2c bus
1211 to run and CFG_I2C_SLAVE to be the address of this node (ie
1212 the cpu's i2c node address).
1214 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1215 sets the cpu up as a master node and so its address should
1216 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1217 p.16-473). So, set CFG_I2C_SLAVE to 0.
1219 That's all that's required for CONFIG_HARD_I2C.
1221 If you use the software i2c interface (CONFIG_SOFT_I2C)
1222 then the following macros need to be defined (examples are
1223 from include/configs/lwmon.h):
1227 (Optional). Any commands necessary to enable the I2C
1228 controller or configure ports.
1230 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1234 (Only for MPC8260 CPU). The I/O port to use (the code
1235 assumes both bits are on the same port). Valid values
1236 are 0..3 for ports A..D.
1240 The code necessary to make the I2C data line active
1241 (driven). If the data line is open collector, this
1244 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1248 The code necessary to make the I2C data line tri-stated
1249 (inactive). If the data line is open collector, this
1252 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1256 Code that returns TRUE if the I2C data line is high,
1259 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1263 If <bit> is TRUE, sets the I2C data line high. If it
1264 is FALSE, it clears it (low).
1266 eg: #define I2C_SDA(bit) \
1267 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1268 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1272 If <bit> is TRUE, sets the I2C clock line high. If it
1273 is FALSE, it clears it (low).
1275 eg: #define I2C_SCL(bit) \
1276 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1277 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1281 This delay is invoked four times per clock cycle so this
1282 controls the rate of data transfer. The data rate thus
1283 is 1 / (I2C_DELAY * 4). Often defined to be something
1286 #define I2C_DELAY udelay(2)
1290 When a board is reset during an i2c bus transfer
1291 chips might think that the current transfer is still
1292 in progress. On some boards it is possible to access
1293 the i2c SCLK line directly, either by using the
1294 processor pin as a GPIO or by having a second pin
1295 connected to the bus. If this option is defined a
1296 custom i2c_init_board() routine in boards/xxx/board.c
1297 is run early in the boot sequence.
1299 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1301 This option enables configuration of bi_iic_fast[] flags
1302 in u-boot bd_info structure based on u-boot environment
1303 variable "i2cfast". (see also i2cfast)
1305 CONFIG_I2C_MULTI_BUS
1307 This option allows the use of multiple I2C buses, each of which
1308 must have a controller. At any point in time, only one bus is
1309 active. To switch to a different bus, use the 'i2c dev' command.
1310 Note that bus numbering is zero-based.
1314 This option specifies a list of I2C devices that will be skipped
1315 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1316 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1317 pairs. Otherwise, specify a 1D array of device addresses
1320 #undef CONFIG_I2C_MULTI_BUS
1321 #define CFG_I2C_NOPROBES {0x50,0x68}
1323 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1325 #define CONFIG_I2C_MULTI_BUS
1326 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1328 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1332 If defined, then this indicates the I2C bus number for DDR SPD.
1333 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1337 If defined, then this indicates the I2C bus number for the RTC.
1338 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1342 If defined, then this indicates the I2C bus number for the DTT.
1343 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1347 Define this option if you want to use Freescale's I2C driver in
1351 - SPI Support: CONFIG_SPI
1353 Enables SPI driver (so far only tested with
1354 SPI EEPROM, also an instance works with Crystal A/D and
1355 D/As on the SACSng board)
1359 Enables extended (16-bit) SPI EEPROM addressing.
1360 (symmetrical to CONFIG_I2C_X)
1364 Enables a software (bit-bang) SPI driver rather than
1365 using hardware support. This is a general purpose
1366 driver that only requires three general I/O port pins
1367 (two outputs, one input) to function. If this is
1368 defined, the board configuration must define several
1369 SPI configuration items (port pins to use, etc). For
1370 an example, see include/configs/sacsng.h.
1372 - FPGA Support: CONFIG_FPGA_COUNT
1374 Specify the number of FPGA devices to support.
1378 Used to specify the types of FPGA devices. For example,
1379 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1381 CFG_FPGA_PROG_FEEDBACK
1383 Enable printing of hash marks during FPGA configuration.
1387 Enable checks on FPGA configuration interface busy
1388 status by the configuration function. This option
1389 will require a board or device specific function to
1394 If defined, a function that provides delays in the FPGA
1395 configuration driver.
1397 CFG_FPGA_CHECK_CTRLC
1398 Allow Control-C to interrupt FPGA configuration
1400 CFG_FPGA_CHECK_ERROR
1402 Check for configuration errors during FPGA bitfile
1403 loading. For example, abort during Virtex II
1404 configuration if the INIT_B line goes low (which
1405 indicated a CRC error).
1409 Maximum time to wait for the INIT_B line to deassert
1410 after PROB_B has been deasserted during a Virtex II
1411 FPGA configuration sequence. The default time is 500
1416 Maximum time to wait for BUSY to deassert during
1417 Virtex II FPGA configuration. The default is 5 mS.
1419 CFG_FPGA_WAIT_CONFIG
1421 Time to wait after FPGA configuration. The default is
1424 - Configuration Management:
1427 If defined, this string will be added to the U-Boot
1428 version information (U_BOOT_VERSION)
1430 - Vendor Parameter Protection:
1432 U-Boot considers the values of the environment
1433 variables "serial#" (Board Serial Number) and
1434 "ethaddr" (Ethernet Address) to be parameters that
1435 are set once by the board vendor / manufacturer, and
1436 protects these variables from casual modification by
1437 the user. Once set, these variables are read-only,
1438 and write or delete attempts are rejected. You can
1439 change this behviour:
1441 If CONFIG_ENV_OVERWRITE is #defined in your config
1442 file, the write protection for vendor parameters is
1443 completely disabled. Anybody can change or delete
1446 Alternatively, if you #define _both_ CONFIG_ETHADDR
1447 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1448 ethernet address is installed in the environment,
1449 which can be changed exactly ONCE by the user. [The
1450 serial# is unaffected by this, i. e. it remains
1456 Define this variable to enable the reservation of
1457 "protected RAM", i. e. RAM which is not overwritten
1458 by U-Boot. Define CONFIG_PRAM to hold the number of
1459 kB you want to reserve for pRAM. You can overwrite
1460 this default value by defining an environment
1461 variable "pram" to the number of kB you want to
1462 reserve. Note that the board info structure will
1463 still show the full amount of RAM. If pRAM is
1464 reserved, a new environment variable "mem" will
1465 automatically be defined to hold the amount of
1466 remaining RAM in a form that can be passed as boot
1467 argument to Linux, for instance like that:
1469 setenv bootargs ... mem=\${mem}
1472 This way you can tell Linux not to use this memory,
1473 either, which results in a memory region that will
1474 not be affected by reboots.
1476 *WARNING* If your board configuration uses automatic
1477 detection of the RAM size, you must make sure that
1478 this memory test is non-destructive. So far, the
1479 following board configurations are known to be
1482 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1483 HERMES, IP860, RPXlite, LWMON, LANTEC,
1484 PCU_E, FLAGADM, TQM8260
1489 Define this variable to stop the system in case of a
1490 fatal error, so that you have to reset it manually.
1491 This is probably NOT a good idea for an embedded
1492 system where you want to system to reboot
1493 automatically as fast as possible, but it may be
1494 useful during development since you can try to debug
1495 the conditions that lead to the situation.
1497 CONFIG_NET_RETRY_COUNT
1499 This variable defines the number of retries for
1500 network operations like ARP, RARP, TFTP, or BOOTP
1501 before giving up the operation. If not defined, a
1502 default value of 5 is used.
1504 - Command Interpreter:
1505 CONFIG_AUTO_COMPLETE
1507 Enable auto completion of commands using TAB.
1509 Note that this feature has NOT been implemented yet
1510 for the "hush" shell.
1515 Define this variable to enable the "hush" shell (from
1516 Busybox) as command line interpreter, thus enabling
1517 powerful command line syntax like
1518 if...then...else...fi conditionals or `&&' and '||'
1519 constructs ("shell scripts").
1521 If undefined, you get the old, much simpler behaviour
1522 with a somewhat smaller memory footprint.
1527 This defines the secondary prompt string, which is
1528 printed when the command interpreter needs more input
1529 to complete a command. Usually "> ".
1533 In the current implementation, the local variables
1534 space and global environment variables space are
1535 separated. Local variables are those you define by
1536 simply typing `name=value'. To access a local
1537 variable later on, you have write `$name' or
1538 `${name}'; to execute the contents of a variable
1539 directly type `$name' at the command prompt.
1541 Global environment variables are those you use
1542 setenv/printenv to work with. To run a command stored
1543 in such a variable, you need to use the run command,
1544 and you must not use the '$' sign to access them.
1546 To store commands and special characters in a
1547 variable, please use double quotation marks
1548 surrounding the whole text of the variable, instead
1549 of the backslashes before semicolons and special
1552 - Commandline Editing and History:
1553 CONFIG_CMDLINE_EDITING
1555 Enable editiong and History functions for interactive
1556 commandline input operations
1558 - Default Environment:
1559 CONFIG_EXTRA_ENV_SETTINGS
1561 Define this to contain any number of null terminated
1562 strings (variable = value pairs) that will be part of
1563 the default environment compiled into the boot image.
1565 For example, place something like this in your
1566 board's config file:
1568 #define CONFIG_EXTRA_ENV_SETTINGS \
1572 Warning: This method is based on knowledge about the
1573 internal format how the environment is stored by the
1574 U-Boot code. This is NOT an official, exported
1575 interface! Although it is unlikely that this format
1576 will change soon, there is no guarantee either.
1577 You better know what you are doing here.
1579 Note: overly (ab)use of the default environment is
1580 discouraged. Make sure to check other ways to preset
1581 the environment like the autoscript function or the
1584 - DataFlash Support:
1585 CONFIG_HAS_DATAFLASH
1587 Defining this option enables DataFlash features and
1588 allows to read/write in Dataflash via the standard
1591 - SystemACE Support:
1594 Adding this option adds support for Xilinx SystemACE
1595 chips attached via some sort of local bus. The address
1596 of the chip must alsh be defined in the
1597 CFG_SYSTEMACE_BASE macro. For example:
1599 #define CONFIG_SYSTEMACE
1600 #define CFG_SYSTEMACE_BASE 0xf0000000
1602 When SystemACE support is added, the "ace" device type
1603 becomes available to the fat commands, i.e. fatls.
1605 - TFTP Fixed UDP Port:
1608 If this is defined, the environment variable tftpsrcp
1609 is used to supply the TFTP UDP source port value.
1610 If tftpsrcp isn't defined, the normal pseudo-random port
1611 number generator is used.
1613 Also, the environment variable tftpdstp is used to supply
1614 the TFTP UDP destination port value. If tftpdstp isn't
1615 defined, the normal port 69 is used.
1617 The purpose for tftpsrcp is to allow a TFTP server to
1618 blindly start the TFTP transfer using the pre-configured
1619 target IP address and UDP port. This has the effect of
1620 "punching through" the (Windows XP) firewall, allowing
1621 the remainder of the TFTP transfer to proceed normally.
1622 A better solution is to properly configure the firewall,
1623 but sometimes that is not allowed.
1625 - Show boot progress:
1626 CONFIG_SHOW_BOOT_PROGRESS
1628 Defining this option allows to add some board-
1629 specific code (calling a user-provided function
1630 "show_boot_progress(int)") that enables you to show
1631 the system's boot progress on some display (for
1632 example, some LED's) on your board. At the moment,
1633 the following checkpoints are implemented:
1636 1 common/cmd_bootm.c before attempting to boot an image
1637 -1 common/cmd_bootm.c Image header has bad magic number
1638 2 common/cmd_bootm.c Image header has correct magic number
1639 -2 common/cmd_bootm.c Image header has bad checksum
1640 3 common/cmd_bootm.c Image header has correct checksum
1641 -3 common/cmd_bootm.c Image data has bad checksum
1642 4 common/cmd_bootm.c Image data has correct checksum
1643 -4 common/cmd_bootm.c Image is for unsupported architecture
1644 5 common/cmd_bootm.c Architecture check OK
1645 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1646 6 common/cmd_bootm.c Image Type check OK
1647 -6 common/cmd_bootm.c gunzip uncompression error
1648 -7 common/cmd_bootm.c Unimplemented compression type
1649 7 common/cmd_bootm.c Uncompression OK
1650 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1651 8 common/cmd_bootm.c Image Type check OK
1652 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1653 9 common/cmd_bootm.c Start initial ramdisk verification
1654 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1655 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1656 10 common/cmd_bootm.c Ramdisk header is OK
1657 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1658 11 common/cmd_bootm.c Ramdisk data has correct checksum
1659 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1660 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1661 13 common/cmd_bootm.c Start multifile image verification
1662 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1663 15 common/cmd_bootm.c All preparation done, transferring control to OS
1665 -30 lib_ppc/board.c Fatal error, hang the system
1666 -31 post/post.c POST test failed, detected by post_output_backlog()
1667 -32 post/post.c POST test failed, detected by post_run_single()
1669 34 common/cmd_doc.c before loading a Image from a DOC device
1670 -35 common/cmd_doc.c Bad usage of "doc" command
1671 35 common/cmd_doc.c correct usage of "doc" command
1672 -36 common/cmd_doc.c No boot device
1673 36 common/cmd_doc.c correct boot device
1674 -37 common/cmd_doc.c Unknown Chip ID on boot device
1675 37 common/cmd_doc.c correct chip ID found, device available
1676 -38 common/cmd_doc.c Read Error on boot device
1677 38 common/cmd_doc.c reading Image header from DOC device OK
1678 -39 common/cmd_doc.c Image header has bad magic number
1679 39 common/cmd_doc.c Image header has correct magic number
1680 -40 common/cmd_doc.c Error reading Image from DOC device
1681 40 common/cmd_doc.c Image header has correct magic number
1682 41 common/cmd_ide.c before loading a Image from a IDE device
1683 -42 common/cmd_ide.c Bad usage of "ide" command
1684 42 common/cmd_ide.c correct usage of "ide" command
1685 -43 common/cmd_ide.c No boot device
1686 43 common/cmd_ide.c boot device found
1687 -44 common/cmd_ide.c Device not available
1688 44 common/cmd_ide.c Device available
1689 -45 common/cmd_ide.c wrong partition selected
1690 45 common/cmd_ide.c partition selected
1691 -46 common/cmd_ide.c Unknown partition table
1692 46 common/cmd_ide.c valid partition table found
1693 -47 common/cmd_ide.c Invalid partition type
1694 47 common/cmd_ide.c correct partition type
1695 -48 common/cmd_ide.c Error reading Image Header on boot device
1696 48 common/cmd_ide.c reading Image Header from IDE device OK
1697 -49 common/cmd_ide.c Image header has bad magic number
1698 49 common/cmd_ide.c Image header has correct magic number
1699 -50 common/cmd_ide.c Image header has bad checksum
1700 50 common/cmd_ide.c Image header has correct checksum
1701 -51 common/cmd_ide.c Error reading Image from IDE device
1702 51 common/cmd_ide.c reading Image from IDE device OK
1703 52 common/cmd_nand.c before loading a Image from a NAND device
1704 -53 common/cmd_nand.c Bad usage of "nand" command
1705 53 common/cmd_nand.c correct usage of "nand" command
1706 -54 common/cmd_nand.c No boot device
1707 54 common/cmd_nand.c boot device found
1708 -55 common/cmd_nand.c Unknown Chip ID on boot device
1709 55 common/cmd_nand.c correct chip ID found, device available
1710 -56 common/cmd_nand.c Error reading Image Header on boot device
1711 56 common/cmd_nand.c reading Image Header from NAND device OK
1712 -57 common/cmd_nand.c Image header has bad magic number
1713 57 common/cmd_nand.c Image header has correct magic number
1714 -58 common/cmd_nand.c Error reading Image from NAND device
1715 58 common/cmd_nand.c reading Image from NAND device OK
1717 -60 common/env_common.c Environment has a bad CRC, using default
1719 64 net/eth.c starting with Ethernetconfiguration.
1720 -64 net/eth.c no Ethernet found.
1721 65 net/eth.c Ethernet found.
1723 -80 common/cmd_net.c usage wrong
1724 80 common/cmd_net.c before calling NetLoop()
1725 -81 common/cmd_net.c some error in NetLoop() occured
1726 81 common/cmd_net.c NetLoop() back without error
1727 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1728 82 common/cmd_net.c trying automatic boot
1729 83 common/cmd_net.c running autoscript
1730 -83 common/cmd_net.c some error in automatic boot or autoscript
1731 84 common/cmd_net.c end without errors
1736 [so far only for SMDK2400 and TRAB boards]
1738 - Modem support endable:
1739 CONFIG_MODEM_SUPPORT
1741 - RTS/CTS Flow control enable:
1744 - Modem debug support:
1745 CONFIG_MODEM_SUPPORT_DEBUG
1747 Enables debugging stuff (char screen[1024], dbg())
1748 for modem support. Useful only with BDI2000.
1750 - Interrupt support (PPC):
1752 There are common interrupt_init() and timer_interrupt()
1753 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1754 for cpu specific initialization. interrupt_init_cpu()
1755 should set decrementer_count to appropriate value. If
1756 cpu resets decrementer automatically after interrupt
1757 (ppc4xx) it should set decrementer_count to zero.
1758 timer_interrupt() calls timer_interrupt_cpu() for cpu
1759 specific handling. If board has watchdog / status_led
1760 / other_activity_monitor it works automatically from
1761 general timer_interrupt().
1765 In the target system modem support is enabled when a
1766 specific key (key combination) is pressed during
1767 power-on. Otherwise U-Boot will boot normally
1768 (autoboot). The key_pressed() fuction is called from
1769 board_init(). Currently key_pressed() is a dummy
1770 function, returning 1 and thus enabling modem
1773 If there are no modem init strings in the
1774 environment, U-Boot proceed to autoboot; the
1775 previous output (banner, info printfs) will be
1778 See also: doc/README.Modem
1781 Configuration Settings:
1782 -----------------------
1784 - CFG_LONGHELP: Defined when you want long help messages included;
1785 undefine this when you're short of memory.
1787 - CFG_PROMPT: This is what U-Boot prints on the console to
1788 prompt for user input.
1790 - CFG_CBSIZE: Buffer size for input from the Console
1792 - CFG_PBSIZE: Buffer size for Console output
1794 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1796 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1797 the application (usually a Linux kernel) when it is
1800 - CFG_BAUDRATE_TABLE:
1801 List of legal baudrate settings for this board.
1803 - CFG_CONSOLE_INFO_QUIET
1804 Suppress display of console information at boot.
1806 - CFG_CONSOLE_IS_IN_ENV
1807 If the board specific function
1808 extern int overwrite_console (void);
1809 returns 1, the stdin, stderr and stdout are switched to the
1810 serial port, else the settings in the environment are used.
1812 - CFG_CONSOLE_OVERWRITE_ROUTINE
1813 Enable the call to overwrite_console().
1815 - CFG_CONSOLE_ENV_OVERWRITE
1816 Enable overwrite of previous console environment settings.
1818 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1819 Begin and End addresses of the area used by the
1823 Enable an alternate, more extensive memory test.
1825 - CFG_MEMTEST_SCRATCH:
1826 Scratch address used by the alternate memory test
1827 You only need to set this if address zero isn't writeable
1829 - CFG_TFTP_LOADADDR:
1830 Default load address for network file downloads
1832 - CFG_LOADS_BAUD_CHANGE:
1833 Enable temporary baudrate change while serial download
1836 Physical start address of SDRAM. _Must_ be 0 here.
1839 Physical start address of Motherboard I/O (if using a
1843 Physical start address of Flash memory.
1846 Physical start address of boot monitor code (set by
1847 make config files to be same as the text base address
1848 (TEXT_BASE) used when linking) - same as
1849 CFG_FLASH_BASE when booting from flash.
1852 Size of memory reserved for monitor code, used to
1853 determine _at_compile_time_ (!) if the environment is
1854 embedded within the U-Boot image, or in a separate
1858 Size of DRAM reserved for malloc() use.
1861 Normally compressed uImages are limited to an
1862 uncompressed size of 8 MBytes. If this is not enough,
1863 you can define CFG_BOOTM_LEN in your board config file
1864 to adjust this setting to your needs.
1867 Maximum size of memory mapped by the startup code of
1868 the Linux kernel; all data that must be processed by
1869 the Linux kernel (bd_info, boot arguments, eventually
1870 initrd image) must be put below this limit.
1872 - CFG_MAX_FLASH_BANKS:
1873 Max number of Flash memory banks
1875 - CFG_MAX_FLASH_SECT:
1876 Max number of sectors on a Flash chip
1878 - CFG_FLASH_ERASE_TOUT:
1879 Timeout for Flash erase operations (in ms)
1881 - CFG_FLASH_WRITE_TOUT:
1882 Timeout for Flash write operations (in ms)
1884 - CFG_FLASH_LOCK_TOUT
1885 Timeout for Flash set sector lock bit operation (in ms)
1887 - CFG_FLASH_UNLOCK_TOUT
1888 Timeout for Flash clear lock bits operation (in ms)
1890 - CFG_FLASH_PROTECTION
1891 If defined, hardware flash sectors protection is used
1892 instead of U-Boot software protection.
1894 - CFG_DIRECT_FLASH_TFTP:
1896 Enable TFTP transfers directly to flash memory;
1897 without this option such a download has to be
1898 performed in two steps: (1) download to RAM, and (2)
1899 copy from RAM to flash.
1901 The two-step approach is usually more reliable, since
1902 you can check if the download worked before you erase
1903 the flash, but in some situations (when sytem RAM is
1904 too limited to allow for a tempory copy of the
1905 downloaded image) this option may be very useful.
1908 Define if the flash driver uses extra elements in the
1909 common flash structure for storing flash geometry.
1911 - CFG_FLASH_CFI_DRIVER
1912 This option also enables the building of the cfi_flash driver
1913 in the drivers directory
1915 - CFG_FLASH_QUIET_TEST
1916 If this option is defined, the common CFI flash doesn't
1917 print it's warning upon not recognized FLASH banks. This
1918 is useful, if some of the configured banks are only
1919 optionally available.
1921 - CFG_RX_ETH_BUFFER:
1922 Defines the number of ethernet receive buffers. On some
1923 ethernet controllers it is recommended to set this value
1924 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1925 buffers can be full shortly after enabling the interface
1926 on high ethernet traffic.
1927 Defaults to 4 if not defined.
1929 The following definitions that deal with the placement and management
1930 of environment data (variable area); in general, we support the
1931 following configurations:
1933 - CFG_ENV_IS_IN_FLASH:
1935 Define this if the environment is in flash memory.
1937 a) The environment occupies one whole flash sector, which is
1938 "embedded" in the text segment with the U-Boot code. This
1939 happens usually with "bottom boot sector" or "top boot
1940 sector" type flash chips, which have several smaller
1941 sectors at the start or the end. For instance, such a
1942 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1943 such a case you would place the environment in one of the
1944 4 kB sectors - with U-Boot code before and after it. With
1945 "top boot sector" type flash chips, you would put the
1946 environment in one of the last sectors, leaving a gap
1947 between U-Boot and the environment.
1951 Offset of environment data (variable area) to the
1952 beginning of flash memory; for instance, with bottom boot
1953 type flash chips the second sector can be used: the offset
1954 for this sector is given here.
1956 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1960 This is just another way to specify the start address of
1961 the flash sector containing the environment (instead of
1964 - CFG_ENV_SECT_SIZE:
1966 Size of the sector containing the environment.
1969 b) Sometimes flash chips have few, equal sized, BIG sectors.
1970 In such a case you don't want to spend a whole sector for
1975 If you use this in combination with CFG_ENV_IS_IN_FLASH
1976 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1977 of this flash sector for the environment. This saves
1978 memory for the RAM copy of the environment.
1980 It may also save flash memory if you decide to use this
1981 when your environment is "embedded" within U-Boot code,
1982 since then the remainder of the flash sector could be used
1983 for U-Boot code. It should be pointed out that this is
1984 STRONGLY DISCOURAGED from a robustness point of view:
1985 updating the environment in flash makes it always
1986 necessary to erase the WHOLE sector. If something goes
1987 wrong before the contents has been restored from a copy in
1988 RAM, your target system will be dead.
1990 - CFG_ENV_ADDR_REDUND
1993 These settings describe a second storage area used to hold
1994 a redundand copy of the environment data, so that there is
1995 a valid backup copy in case there is a power failure during
1996 a "saveenv" operation.
1998 BE CAREFUL! Any changes to the flash layout, and some changes to the
1999 source code will make it necessary to adapt <board>/u-boot.lds*
2003 - CFG_ENV_IS_IN_NVRAM:
2005 Define this if you have some non-volatile memory device
2006 (NVRAM, battery buffered SRAM) which you want to use for the
2012 These two #defines are used to determin the memory area you
2013 want to use for environment. It is assumed that this memory
2014 can just be read and written to, without any special
2017 BE CAREFUL! The first access to the environment happens quite early
2018 in U-Boot initalization (when we try to get the setting of for the
2019 console baudrate). You *MUST* have mappend your NVRAM area then, or
2022 Please note that even with NVRAM we still use a copy of the
2023 environment in RAM: we could work on NVRAM directly, but we want to
2024 keep settings there always unmodified except somebody uses "saveenv"
2025 to save the current settings.
2028 - CFG_ENV_IS_IN_EEPROM:
2030 Use this if you have an EEPROM or similar serial access
2031 device and a driver for it.
2036 These two #defines specify the offset and size of the
2037 environment area within the total memory of your EEPROM.
2039 - CFG_I2C_EEPROM_ADDR:
2040 If defined, specified the chip address of the EEPROM device.
2041 The default address is zero.
2043 - CFG_EEPROM_PAGE_WRITE_BITS:
2044 If defined, the number of bits used to address bytes in a
2045 single page in the EEPROM device. A 64 byte page, for example
2046 would require six bits.
2048 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2049 If defined, the number of milliseconds to delay between
2050 page writes. The default is zero milliseconds.
2052 - CFG_I2C_EEPROM_ADDR_LEN:
2053 The length in bytes of the EEPROM memory array address. Note
2054 that this is NOT the chip address length!
2056 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2057 EEPROM chips that implement "address overflow" are ones
2058 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2059 address and the extra bits end up in the "chip address" bit
2060 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2063 Note that we consider the length of the address field to
2064 still be one byte because the extra address bits are hidden
2065 in the chip address.
2068 The size in bytes of the EEPROM device.
2071 - CFG_ENV_IS_IN_DATAFLASH:
2073 Define this if you have a DataFlash memory device which you
2074 want to use for the environment.
2080 These three #defines specify the offset and size of the
2081 environment area within the total memory of your DataFlash placed
2082 at the specified address.
2084 - CFG_ENV_IS_IN_NAND:
2086 Define this if you have a NAND device which you want to use
2087 for the environment.
2092 These two #defines specify the offset and size of the environment
2093 area within the first NAND device.
2095 - CFG_ENV_OFFSET_REDUND
2097 This setting describes a second storage area of CFG_ENV_SIZE
2098 size used to hold a redundant copy of the environment data,
2099 so that there is a valid backup copy in case there is a
2100 power failure during a "saveenv" operation.
2102 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2103 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2104 the NAND devices block size.
2106 - CFG_SPI_INIT_OFFSET
2108 Defines offset to the initial SPI buffer area in DPRAM. The
2109 area is used at an early stage (ROM part) if the environment
2110 is configured to reside in the SPI EEPROM: We need a 520 byte
2111 scratch DPRAM area. It is used between the two initialization
2112 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2113 to be a good choice since it makes it far enough from the
2114 start of the data area as well as from the stack pointer.
2116 Please note that the environment is read-only as long as the monitor
2117 has been relocated to RAM and a RAM copy of the environment has been
2118 created; also, when using EEPROM you will have to use getenv_r()
2119 until then to read environment variables.
2121 The environment is protected by a CRC32 checksum. Before the monitor
2122 is relocated into RAM, as a result of a bad CRC you will be working
2123 with the compiled-in default environment - *silently*!!! [This is
2124 necessary, because the first environment variable we need is the
2125 "baudrate" setting for the console - if we have a bad CRC, we don't
2126 have any device yet where we could complain.]
2128 Note: once the monitor has been relocated, then it will complain if
2129 the default environment is used; a new CRC is computed as soon as you
2130 use the "saveenv" command to store a valid environment.
2132 - CFG_FAULT_ECHO_LINK_DOWN:
2133 Echo the inverted Ethernet link state to the fault LED.
2135 Note: If this option is active, then CFG_FAULT_MII_ADDR
2136 also needs to be defined.
2138 - CFG_FAULT_MII_ADDR:
2139 MII address of the PHY to check for the Ethernet link state.
2141 - CFG_64BIT_VSPRINTF:
2142 Makes vsprintf (and all *printf functions) support printing
2143 of 64bit values by using the L quantifier
2145 - CFG_64BIT_STRTOUL:
2146 Adds simple_strtoull that returns a 64bit value
2148 Low Level (hardware related) configuration options:
2149 ---------------------------------------------------
2151 - CFG_CACHELINE_SIZE:
2152 Cache Line Size of the CPU.
2155 Default address of the IMMR after system reset.
2157 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2158 and RPXsuper) to be able to adjust the position of
2159 the IMMR register after a reset.
2161 - Floppy Disk Support:
2162 CFG_FDC_DRIVE_NUMBER
2164 the default drive number (default value 0)
2168 defines the spacing between fdc chipset registers
2173 defines the offset of register from address. It
2174 depends on which part of the data bus is connected to
2175 the fdc chipset. (default value 0)
2177 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2178 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2181 if CFG_FDC_HW_INIT is defined, then the function
2182 fdc_hw_init() is called at the beginning of the FDC
2183 setup. fdc_hw_init() must be provided by the board
2184 source code. It is used to make hardware dependant
2187 - CFG_IMMR: Physical address of the Internal Memory.
2188 DO NOT CHANGE unless you know exactly what you're
2189 doing! (11-4) [MPC8xx/82xx systems only]
2191 - CFG_INIT_RAM_ADDR:
2193 Start address of memory area that can be used for
2194 initial data and stack; please note that this must be
2195 writable memory that is working WITHOUT special
2196 initialization, i. e. you CANNOT use normal RAM which
2197 will become available only after programming the
2198 memory controller and running certain initialization
2201 U-Boot uses the following memory types:
2202 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2203 - MPC824X: data cache
2204 - PPC4xx: data cache
2206 - CFG_GBL_DATA_OFFSET:
2208 Offset of the initial data structure in the memory
2209 area defined by CFG_INIT_RAM_ADDR. Usually
2210 CFG_GBL_DATA_OFFSET is chosen such that the initial
2211 data is located at the end of the available space
2212 (sometimes written as (CFG_INIT_RAM_END -
2213 CFG_INIT_DATA_SIZE), and the initial stack is just
2214 below that area (growing from (CFG_INIT_RAM_ADDR +
2215 CFG_GBL_DATA_OFFSET) downward.
2218 On the MPC824X (or other systems that use the data
2219 cache for initial memory) the address chosen for
2220 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2221 point to an otherwise UNUSED address space between
2222 the top of RAM and the start of the PCI space.
2224 - CFG_SIUMCR: SIU Module Configuration (11-6)
2226 - CFG_SYPCR: System Protection Control (11-9)
2228 - CFG_TBSCR: Time Base Status and Control (11-26)
2230 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2232 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2234 - CFG_SCCR: System Clock and reset Control Register (15-27)
2236 - CFG_OR_TIMING_SDRAM:
2240 periodic timer for refresh
2242 - CFG_DER: Debug Event Register (37-47)
2244 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2245 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2246 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2248 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2250 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2251 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2252 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2253 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2255 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2256 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2257 Machine Mode Register and Memory Periodic Timer
2258 Prescaler definitions (SDRAM timing)
2260 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2261 enable I2C microcode relocation patch (MPC8xx);
2262 define relocation offset in DPRAM [DSP2]
2264 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2265 enable SPI microcode relocation patch (MPC8xx);
2266 define relocation offset in DPRAM [SCC4]
2269 Use OSCM clock mode on MBX8xx board. Be careful,
2270 wrong setting might damage your board. Read
2271 doc/README.MBX before setting this variable!
2273 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2274 Offset of the bootmode word in DPRAM used by post
2275 (Power On Self Tests). This definition overrides
2276 #define'd default value in commproc.h resp.
2279 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2280 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2281 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2282 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2283 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2284 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2285 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2286 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2287 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2290 Get DDR timing information from an I2C EEPROM. Common with pluggable
2291 memory modules such as SODIMMs
2293 I2C address of the SPD EEPROM
2296 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2297 Note that the value must resolve to something your driver can deal with.
2299 - CFG_83XX_DDR_USES_CS0
2300 Only for 83xx systems. If specified, then DDR should be configured
2301 using CS0 and CS1 instead of CS2 and CS3.
2303 - CFG_83XX_DDR_USES_CS0
2304 Only for 83xx systems. If specified, then DDR should be configured
2305 using CS0 and CS1 instead of CS2 and CS3.
2307 - CONFIG_ETHER_ON_FEC[12]
2308 Define to enable FEC[12] on a 8xx series processor.
2310 - CONFIG_FEC[12]_PHY
2311 Define to the hardcoded PHY address which corresponds
2312 to the given FEC; i. e.
2313 #define CONFIG_FEC1_PHY 4
2314 means that the PHY with address 4 is connected to FEC1
2316 When set to -1, means to probe for first available.
2318 - CONFIG_FEC[12]_PHY_NORXERR
2319 The PHY does not have a RXERR line (RMII only).
2320 (so program the FEC to ignore it).
2323 Enable RMII mode for all FECs.
2324 Note that this is a global option, we can't
2325 have one FEC in standard MII mode and another in RMII mode.
2327 - CONFIG_CRC32_VERIFY
2328 Add a verify option to the crc32 command.
2331 => crc32 -v <address> <count> <crc32>
2333 Where address/count indicate a memory area
2334 and crc32 is the correct crc32 which the
2338 Add the "loopw" memory command. This only takes effect if
2339 the memory commands are activated globally (CONFIG_CMD_MEM).
2342 Add the "mdc" and "mwc" memory commands. These are cyclic
2347 This command will print 4 bytes (10,11,12,13) each 500 ms.
2349 => mwc.l 100 12345678 10
2350 This command will write 12345678 to address 100 all 10 ms.
2352 This only takes effect if the memory commands are activated
2353 globally (CONFIG_CMD_MEM).
2355 - CONFIG_SKIP_LOWLEVEL_INIT
2356 - CONFIG_SKIP_RELOCATE_UBOOT
2358 [ARM only] If these variables are defined, then
2359 certain low level initializations (like setting up
2360 the memory controller) are omitted and/or U-Boot does
2361 not relocate itself into RAM.
2362 Normally these variables MUST NOT be defined. The
2363 only exception is when U-Boot is loaded (to RAM) by
2364 some other boot loader or by a debugger which
2365 performs these intializations itself.
2368 Building the Software:
2369 ======================
2371 Building U-Boot has been tested in native PPC environments (on a
2372 PowerBook G3 running LinuxPPC 2000) and in cross environments
2373 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2376 If you are not using a native PPC environment, it is assumed that you
2377 have the GNU cross compiling tools available in your path and named
2378 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2379 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2380 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2383 CROSS_COMPILE = ppc_4xx-
2386 U-Boot is intended to be simple to build. After installing the
2387 sources you must configure U-Boot for one specific board type. This
2392 where "NAME_config" is the name of one of the existing
2393 configurations; see the main Makefile for supported names.
2395 Note: for some board special configuration names may exist; check if
2396 additional information is available from the board vendor; for
2397 instance, the TQM823L systems are available without (standard)
2398 or with LCD support. You can select such additional "features"
2399 when chosing the configuration, i. e.
2402 - will configure for a plain TQM823L, i. e. no LCD support
2404 make TQM823L_LCD_config
2405 - will configure for a TQM823L with U-Boot console on LCD
2410 Finally, type "make all", and you should get some working U-Boot
2411 images ready for download to / installation on your system:
2413 - "u-boot.bin" is a raw binary image
2414 - "u-boot" is an image in ELF binary format
2415 - "u-boot.srec" is in Motorola S-Record format
2417 By default the build is performed locally and the objects are saved
2418 in the source directory. One of the two methods can be used to change
2419 this behavior and build U-Boot to some external directory:
2421 1. Add O= to the make command line invocations:
2423 make O=/tmp/build distclean
2424 make O=/tmp/build NAME_config
2425 make O=/tmp/build all
2427 2. Set environment variable BUILD_DIR to point to the desired location:
2429 export BUILD_DIR=/tmp/build
2434 Note that the command line "O=" setting overrides the BUILD_DIR environment
2438 Please be aware that the Makefiles assume you are using GNU make, so
2439 for instance on NetBSD you might need to use "gmake" instead of
2443 If the system board that you have is not listed, then you will need
2444 to port U-Boot to your hardware platform. To do this, follow these
2447 1. Add a new configuration option for your board to the toplevel
2448 "Makefile" and to the "MAKEALL" script, using the existing
2449 entries as examples. Note that here and at many other places
2450 boards and other names are listed in alphabetical sort order. Please
2452 2. Create a new directory to hold your board specific code. Add any
2453 files you need. In your board directory, you will need at least
2454 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2455 3. Create a new configuration file "include/configs/<board>.h" for
2457 3. If you're porting U-Boot to a new CPU, then also create a new
2458 directory to hold your CPU specific code. Add any files you need.
2459 4. Run "make <board>_config" with your new name.
2460 5. Type "make", and you should get a working "u-boot.srec" file
2461 to be installed on your target system.
2462 6. Debug and solve any problems that might arise.
2463 [Of course, this last step is much harder than it sounds.]
2466 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2467 ==============================================================
2469 If you have modified U-Boot sources (for instance added a new board
2470 or support for new devices, a new CPU, etc.) you are expected to
2471 provide feedback to the other developers. The feedback normally takes
2472 the form of a "patch", i. e. a context diff against a certain (latest
2473 official or latest in CVS) version of U-Boot sources.
2475 But before you submit such a patch, please verify that your modifi-
2476 cation did not break existing code. At least make sure that *ALL* of
2477 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2478 just run the "MAKEALL" script, which will configure and build U-Boot
2479 for ALL supported system. Be warned, this will take a while. You can
2480 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2481 environment variable to the script, i. e. to use the cross tools from
2482 MontaVista's Hard Hat Linux you can type
2484 CROSS_COMPILE=ppc_8xx- MAKEALL
2486 or to build on a native PowerPC system you can type
2488 CROSS_COMPILE=' ' MAKEALL
2490 When using the MAKEALL script, the default behaviour is to build U-Boot
2491 in the source directory. This location can be changed by setting the
2492 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2493 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2494 <source dir>/LOG directory. This default location can be changed by
2495 setting the MAKEALL_LOGDIR environment variable. For example:
2497 export BUILD_DIR=/tmp/build
2498 export MAKEALL_LOGDIR=/tmp/log
2499 CROSS_COMPILE=ppc_8xx- MAKEALL
2501 With the above settings build objects are saved in the /tmp/build, log
2502 files are saved in the /tmp/log and the source tree remains clean during
2503 the whole build process.
2506 See also "U-Boot Porting Guide" below.
2509 Monitor Commands - Overview:
2510 ============================
2512 go - start application at address 'addr'
2513 run - run commands in an environment variable
2514 bootm - boot application image from memory
2515 bootp - boot image via network using BootP/TFTP protocol
2516 tftpboot- boot image via network using TFTP protocol
2517 and env variables "ipaddr" and "serverip"
2518 (and eventually "gatewayip")
2519 rarpboot- boot image via network using RARP/TFTP protocol
2520 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2521 loads - load S-Record file over serial line
2522 loadb - load binary file over serial line (kermit mode)
2524 mm - memory modify (auto-incrementing)
2525 nm - memory modify (constant address)
2526 mw - memory write (fill)
2528 cmp - memory compare
2529 crc32 - checksum calculation
2530 imd - i2c memory display
2531 imm - i2c memory modify (auto-incrementing)
2532 inm - i2c memory modify (constant address)
2533 imw - i2c memory write (fill)
2534 icrc32 - i2c checksum calculation
2535 iprobe - probe to discover valid I2C chip addresses
2536 iloop - infinite loop on address range
2537 isdram - print SDRAM configuration information
2538 sspi - SPI utility commands
2539 base - print or set address offset
2540 printenv- print environment variables
2541 setenv - set environment variables
2542 saveenv - save environment variables to persistent storage
2543 protect - enable or disable FLASH write protection
2544 erase - erase FLASH memory
2545 flinfo - print FLASH memory information
2546 bdinfo - print Board Info structure
2547 iminfo - print header information for application image
2548 coninfo - print console devices and informations
2549 ide - IDE sub-system
2550 loop - infinite loop on address range
2551 loopw - infinite write loop on address range
2552 mtest - simple RAM test
2553 icache - enable or disable instruction cache
2554 dcache - enable or disable data cache
2555 reset - Perform RESET of the CPU
2556 echo - echo args to console
2557 version - print monitor version
2558 help - print online help
2559 ? - alias for 'help'
2562 Monitor Commands - Detailed Description:
2563 ========================================
2567 For now: just type "help <command>".
2570 Environment Variables:
2571 ======================
2573 U-Boot supports user configuration using Environment Variables which
2574 can be made persistent by saving to Flash memory.
2576 Environment Variables are set using "setenv", printed using
2577 "printenv", and saved to Flash using "saveenv". Using "setenv"
2578 without a value can be used to delete a variable from the
2579 environment. As long as you don't save the environment you are
2580 working with an in-memory copy. In case the Flash area containing the
2581 environment is erased by accident, a default environment is provided.
2583 Some configuration options can be set using Environment Variables:
2585 baudrate - see CONFIG_BAUDRATE
2587 bootdelay - see CONFIG_BOOTDELAY
2589 bootcmd - see CONFIG_BOOTCOMMAND
2591 bootargs - Boot arguments when booting an RTOS image
2593 bootfile - Name of the image to load with TFTP
2595 autoload - if set to "no" (any string beginning with 'n'),
2596 "bootp" will just load perform a lookup of the
2597 configuration from the BOOTP server, but not try to
2598 load any image using TFTP
2600 autostart - if set to "yes", an image loaded using the "bootp",
2601 "rarpboot", "tftpboot" or "diskboot" commands will
2602 be automatically started (by internally calling
2605 If set to "no", a standalone image passed to the
2606 "bootm" command will be copied to the load address
2607 (and eventually uncompressed), but NOT be started.
2608 This can be used to load and uncompress arbitrary
2611 i2cfast - (PPC405GP|PPC405EP only)
2612 if set to 'y' configures Linux I2C driver for fast
2613 mode (400kHZ). This environment variable is used in
2614 initialization code. So, for changes to be effective
2615 it must be saved and board must be reset.
2617 initrd_high - restrict positioning of initrd images:
2618 If this variable is not set, initrd images will be
2619 copied to the highest possible address in RAM; this
2620 is usually what you want since it allows for
2621 maximum initrd size. If for some reason you want to
2622 make sure that the initrd image is loaded below the
2623 CFG_BOOTMAPSZ limit, you can set this environment
2624 variable to a value of "no" or "off" or "0".
2625 Alternatively, you can set it to a maximum upper
2626 address to use (U-Boot will still check that it
2627 does not overwrite the U-Boot stack and data).
2629 For instance, when you have a system with 16 MB
2630 RAM, and want to reserve 4 MB from use by Linux,
2631 you can do this by adding "mem=12M" to the value of
2632 the "bootargs" variable. However, now you must make
2633 sure that the initrd image is placed in the first
2634 12 MB as well - this can be done with
2636 setenv initrd_high 00c00000
2638 If you set initrd_high to 0xFFFFFFFF, this is an
2639 indication to U-Boot that all addresses are legal
2640 for the Linux kernel, including addresses in flash
2641 memory. In this case U-Boot will NOT COPY the
2642 ramdisk at all. This may be useful to reduce the
2643 boot time on your system, but requires that this
2644 feature is supported by your Linux kernel.
2646 ipaddr - IP address; needed for tftpboot command
2648 loadaddr - Default load address for commands like "bootp",
2649 "rarpboot", "tftpboot", "loadb" or "diskboot"
2651 loads_echo - see CONFIG_LOADS_ECHO
2653 serverip - TFTP server IP address; needed for tftpboot command
2655 bootretry - see CONFIG_BOOT_RETRY_TIME
2657 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2659 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2661 ethprime - When CONFIG_NET_MULTI is enabled controls which
2662 interface is used first.
2664 ethact - When CONFIG_NET_MULTI is enabled controls which
2665 interface is currently active. For example you
2666 can do the following
2668 => setenv ethact FEC ETHERNET
2669 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2670 => setenv ethact SCC ETHERNET
2671 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2673 netretry - When set to "no" each network operation will
2674 either succeed or fail without retrying.
2675 When set to "once" the network operation will
2676 fail when all the available network interfaces
2677 are tried once without success.
2678 Useful on scripts which control the retry operation
2681 tftpsrcport - If this is set, the value is used for TFTP's
2684 tftpdstport - If this is set, the value is used for TFTP's UDP
2685 destination port instead of the Well Know Port 69.
2687 vlan - When set to a value < 4095 the traffic over
2688 ethernet is encapsulated/received over 802.1q
2691 The following environment variables may be used and automatically
2692 updated by the network boot commands ("bootp" and "rarpboot"),
2693 depending the information provided by your boot server:
2695 bootfile - see above
2696 dnsip - IP address of your Domain Name Server
2697 dnsip2 - IP address of your secondary Domain Name Server
2698 gatewayip - IP address of the Gateway (Router) to use
2699 hostname - Target hostname
2701 netmask - Subnet Mask
2702 rootpath - Pathname of the root filesystem on the NFS server
2703 serverip - see above
2706 There are two special Environment Variables:
2708 serial# - contains hardware identification information such
2709 as type string and/or serial number
2710 ethaddr - Ethernet address
2712 These variables can be set only once (usually during manufacturing of
2713 the board). U-Boot refuses to delete or overwrite these variables
2714 once they have been set once.
2717 Further special Environment Variables:
2719 ver - Contains the U-Boot version string as printed
2720 with the "version" command. This variable is
2721 readonly (see CONFIG_VERSION_VARIABLE).
2724 Please note that changes to some configuration parameters may take
2725 only effect after the next boot (yes, that's just like Windoze :-).
2728 Command Line Parsing:
2729 =====================
2731 There are two different command line parsers available with U-Boot:
2732 the old "simple" one, and the much more powerful "hush" shell:
2734 Old, simple command line parser:
2735 --------------------------------
2737 - supports environment variables (through setenv / saveenv commands)
2738 - several commands on one line, separated by ';'
2739 - variable substitution using "... ${name} ..." syntax
2740 - special characters ('$', ';') can be escaped by prefixing with '\',
2742 setenv bootcmd bootm \${address}
2743 - You can also escape text by enclosing in single apostrophes, for example:
2744 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2749 - similar to Bourne shell, with control structures like
2750 if...then...else...fi, for...do...done; while...do...done,
2751 until...do...done, ...
2752 - supports environment ("global") variables (through setenv / saveenv
2753 commands) and local shell variables (through standard shell syntax
2754 "name=value"); only environment variables can be used with "run"
2760 (1) If a command line (or an environment variable executed by a "run"
2761 command) contains several commands separated by semicolon, and
2762 one of these commands fails, then the remaining commands will be
2765 (2) If you execute several variables with one call to run (i. e.
2766 calling run with a list af variables as arguments), any failing
2767 command will cause "run" to terminate, i. e. the remaining
2768 variables are not executed.
2770 Note for Redundant Ethernet Interfaces:
2771 =======================================
2773 Some boards come with redundant ethernet interfaces; U-Boot supports
2774 such configurations and is capable of automatic selection of a
2775 "working" interface when needed. MAC assignment works as follows:
2777 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2778 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2779 "eth1addr" (=>eth1), "eth2addr", ...
2781 If the network interface stores some valid MAC address (for instance
2782 in SROM), this is used as default address if there is NO correspon-
2783 ding setting in the environment; if the corresponding environment
2784 variable is set, this overrides the settings in the card; that means:
2786 o If the SROM has a valid MAC address, and there is no address in the
2787 environment, the SROM's address is used.
2789 o If there is no valid address in the SROM, and a definition in the
2790 environment exists, then the value from the environment variable is
2793 o If both the SROM and the environment contain a MAC address, and
2794 both addresses are the same, this MAC address is used.
2796 o If both the SROM and the environment contain a MAC address, and the
2797 addresses differ, the value from the environment is used and a
2800 o If neither SROM nor the environment contain a MAC address, an error
2807 The "boot" commands of this monitor operate on "image" files which
2808 can be basicly anything, preceeded by a special header; see the
2809 definitions in include/image.h for details; basicly, the header
2810 defines the following image properties:
2812 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2813 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2814 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2815 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2816 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2817 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2818 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2819 * Compression Type (uncompressed, gzip, bzip2)
2825 The header is marked by a special Magic Number, and both the header
2826 and the data portions of the image are secured against corruption by
2833 Although U-Boot should support any OS or standalone application
2834 easily, the main focus has always been on Linux during the design of
2837 U-Boot includes many features that so far have been part of some
2838 special "boot loader" code within the Linux kernel. Also, any
2839 "initrd" images to be used are no longer part of one big Linux image;
2840 instead, kernel and "initrd" are separate images. This implementation
2841 serves several purposes:
2843 - the same features can be used for other OS or standalone
2844 applications (for instance: using compressed images to reduce the
2845 Flash memory footprint)
2847 - it becomes much easier to port new Linux kernel versions because
2848 lots of low-level, hardware dependent stuff are done by U-Boot
2850 - the same Linux kernel image can now be used with different "initrd"
2851 images; of course this also means that different kernel images can
2852 be run with the same "initrd". This makes testing easier (you don't
2853 have to build a new "zImage.initrd" Linux image when you just
2854 change a file in your "initrd"). Also, a field-upgrade of the
2855 software is easier now.
2861 Porting Linux to U-Boot based systems:
2862 ---------------------------------------
2864 U-Boot cannot save you from doing all the necessary modifications to
2865 configure the Linux device drivers for use with your target hardware
2866 (no, we don't intend to provide a full virtual machine interface to
2869 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2871 Just make sure your machine specific header file (for instance
2872 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2873 Information structure as we define in include/u-boot.h, and make
2874 sure that your definition of IMAP_ADDR uses the same value as your
2875 U-Boot configuration in CFG_IMMR.
2878 Configuring the Linux kernel:
2879 -----------------------------
2881 No specific requirements for U-Boot. Make sure you have some root
2882 device (initial ramdisk, NFS) for your target system.
2885 Building a Linux Image:
2886 -----------------------
2888 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2889 not used. If you use recent kernel source, a new build target
2890 "uImage" will exist which automatically builds an image usable by
2891 U-Boot. Most older kernels also have support for a "pImage" target,
2892 which was introduced for our predecessor project PPCBoot and uses a
2893 100% compatible format.
2902 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2903 encapsulate a compressed Linux kernel image with header information,
2904 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2906 * build a standard "vmlinux" kernel image (in ELF binary format):
2908 * convert the kernel into a raw binary image:
2910 ${CROSS_COMPILE}-objcopy -O binary \
2911 -R .note -R .comment \
2912 -S vmlinux linux.bin
2914 * compress the binary image:
2918 * package compressed binary image for U-Boot:
2920 mkimage -A ppc -O linux -T kernel -C gzip \
2921 -a 0 -e 0 -n "Linux Kernel Image" \
2922 -d linux.bin.gz uImage
2925 The "mkimage" tool can also be used to create ramdisk images for use
2926 with U-Boot, either separated from the Linux kernel image, or
2927 combined into one file. "mkimage" encapsulates the images with a 64
2928 byte header containing information about target architecture,
2929 operating system, image type, compression method, entry points, time
2930 stamp, CRC32 checksums, etc.
2932 "mkimage" can be called in two ways: to verify existing images and
2933 print the header information, or to build new images.
2935 In the first form (with "-l" option) mkimage lists the information
2936 contained in the header of an existing U-Boot image; this includes
2937 checksum verification:
2939 tools/mkimage -l image
2940 -l ==> list image header information
2942 The second form (with "-d" option) is used to build a U-Boot image
2943 from a "data file" which is used as image payload:
2945 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2946 -n name -d data_file image
2947 -A ==> set architecture to 'arch'
2948 -O ==> set operating system to 'os'
2949 -T ==> set image type to 'type'
2950 -C ==> set compression type 'comp'
2951 -a ==> set load address to 'addr' (hex)
2952 -e ==> set entry point to 'ep' (hex)
2953 -n ==> set image name to 'name'
2954 -d ==> use image data from 'datafile'
2956 Right now, all Linux kernels for PowerPC systems use the same load
2957 address (0x00000000), but the entry point address depends on the
2960 - 2.2.x kernels have the entry point at 0x0000000C,
2961 - 2.3.x and later kernels have the entry point at 0x00000000.
2963 So a typical call to build a U-Boot image would read:
2965 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2966 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2967 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2968 > examples/uImage.TQM850L
2969 Image Name: 2.4.4 kernel for TQM850L
2970 Created: Wed Jul 19 02:34:59 2000
2971 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2972 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2973 Load Address: 0x00000000
2974 Entry Point: 0x00000000
2976 To verify the contents of the image (or check for corruption):
2978 -> tools/mkimage -l examples/uImage.TQM850L
2979 Image Name: 2.4.4 kernel for TQM850L
2980 Created: Wed Jul 19 02:34:59 2000
2981 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2982 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2983 Load Address: 0x00000000
2984 Entry Point: 0x00000000
2986 NOTE: for embedded systems where boot time is critical you can trade
2987 speed for memory and install an UNCOMPRESSED image instead: this
2988 needs more space in Flash, but boots much faster since it does not
2989 need to be uncompressed:
2991 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2992 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2993 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2994 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2995 > examples/uImage.TQM850L-uncompressed
2996 Image Name: 2.4.4 kernel for TQM850L
2997 Created: Wed Jul 19 02:34:59 2000
2998 Image Type: PowerPC Linux Kernel Image (uncompressed)
2999 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3000 Load Address: 0x00000000
3001 Entry Point: 0x00000000
3004 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3005 when your kernel is intended to use an initial ramdisk:
3007 -> tools/mkimage -n 'Simple Ramdisk Image' \
3008 > -A ppc -O linux -T ramdisk -C gzip \
3009 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3010 Image Name: Simple Ramdisk Image
3011 Created: Wed Jan 12 14:01:50 2000
3012 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3013 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3014 Load Address: 0x00000000
3015 Entry Point: 0x00000000
3018 Installing a Linux Image:
3019 -------------------------
3021 To downloading a U-Boot image over the serial (console) interface,
3022 you must convert the image to S-Record format:
3024 objcopy -I binary -O srec examples/image examples/image.srec
3026 The 'objcopy' does not understand the information in the U-Boot
3027 image header, so the resulting S-Record file will be relative to
3028 address 0x00000000. To load it to a given address, you need to
3029 specify the target address as 'offset' parameter with the 'loads'
3032 Example: install the image to address 0x40100000 (which on the
3033 TQM8xxL is in the first Flash bank):
3035 => erase 40100000 401FFFFF
3041 ## Ready for S-Record download ...
3042 ~>examples/image.srec
3043 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3045 15989 15990 15991 15992
3046 [file transfer complete]
3048 ## Start Addr = 0x00000000
3051 You can check the success of the download using the 'iminfo' command;
3052 this includes a checksum verification so you can be sure no data
3053 corruption happened:
3057 ## Checking Image at 40100000 ...
3058 Image Name: 2.2.13 for initrd on TQM850L
3059 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3060 Data Size: 335725 Bytes = 327 kB = 0 MB
3061 Load Address: 00000000
3062 Entry Point: 0000000c
3063 Verifying Checksum ... OK
3069 The "bootm" command is used to boot an application that is stored in
3070 memory (RAM or Flash). In case of a Linux kernel image, the contents
3071 of the "bootargs" environment variable is passed to the kernel as
3072 parameters. You can check and modify this variable using the
3073 "printenv" and "setenv" commands:
3076 => printenv bootargs
3077 bootargs=root=/dev/ram
3079 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3081 => printenv bootargs
3082 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3085 ## Booting Linux kernel at 40020000 ...
3086 Image Name: 2.2.13 for NFS on TQM850L
3087 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3088 Data Size: 381681 Bytes = 372 kB = 0 MB
3089 Load Address: 00000000
3090 Entry Point: 0000000c
3091 Verifying Checksum ... OK
3092 Uncompressing Kernel Image ... OK
3093 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
3094 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3095 time_init: decrementer frequency = 187500000/60
3096 Calibrating delay loop... 49.77 BogoMIPS
3097 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3100 If you want to boot a Linux kernel with initial ram disk, you pass
3101 the memory addresses of both the kernel and the initrd image (PPBCOOT
3102 format!) to the "bootm" command:
3104 => imi 40100000 40200000
3106 ## Checking Image at 40100000 ...
3107 Image Name: 2.2.13 for initrd on TQM850L
3108 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3109 Data Size: 335725 Bytes = 327 kB = 0 MB
3110 Load Address: 00000000
3111 Entry Point: 0000000c
3112 Verifying Checksum ... OK
3114 ## Checking Image at 40200000 ...
3115 Image Name: Simple Ramdisk Image
3116 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3117 Data Size: 566530 Bytes = 553 kB = 0 MB
3118 Load Address: 00000000
3119 Entry Point: 00000000
3120 Verifying Checksum ... OK
3122 => bootm 40100000 40200000
3123 ## Booting Linux kernel at 40100000 ...
3124 Image Name: 2.2.13 for initrd on TQM850L
3125 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3126 Data Size: 335725 Bytes = 327 kB = 0 MB
3127 Load Address: 00000000
3128 Entry Point: 0000000c
3129 Verifying Checksum ... OK
3130 Uncompressing Kernel Image ... OK
3131 ## Loading RAMDisk Image at 40200000 ...
3132 Image Name: Simple Ramdisk Image
3133 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3134 Data Size: 566530 Bytes = 553 kB = 0 MB
3135 Load Address: 00000000
3136 Entry Point: 00000000
3137 Verifying Checksum ... OK
3138 Loading Ramdisk ... OK
3139 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
3140 Boot arguments: root=/dev/ram
3141 time_init: decrementer frequency = 187500000/60
3142 Calibrating delay loop... 49.77 BogoMIPS
3144 RAMDISK: Compressed image found at block 0
3145 VFS: Mounted root (ext2 filesystem).
3149 Boot Linux and pass a flat device tree:
3152 First, U-Boot must be compiled with the appropriate defines. See the section
3153 titled "Linux Kernel Interface" above for a more in depth explanation. The
3154 following is an example of how to start a kernel and pass an updated
3160 oft=oftrees/mpc8540ads.dtb
3161 => tftp $oftaddr $oft
3162 Speed: 1000, full duplex
3164 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3165 Filename 'oftrees/mpc8540ads.dtb'.
3166 Load address: 0x300000
3169 Bytes transferred = 4106 (100a hex)
3170 => tftp $loadaddr $bootfile
3171 Speed: 1000, full duplex
3173 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3175 Load address: 0x200000
3176 Loading:############
3178 Bytes transferred = 1029407 (fb51f hex)
3183 => bootm $loadaddr - $oftaddr
3184 ## Booting image at 00200000 ...
3185 Image Name: Linux-2.6.17-dirty
3186 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3187 Data Size: 1029343 Bytes = 1005.2 kB
3188 Load Address: 00000000
3189 Entry Point: 00000000
3190 Verifying Checksum ... OK
3191 Uncompressing Kernel Image ... OK
3192 Booting using flat device tree at 0x300000
3193 Using MPC85xx ADS machine description
3194 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3198 More About U-Boot Image Types:
3199 ------------------------------
3201 U-Boot supports the following image types:
3203 "Standalone Programs" are directly runnable in the environment
3204 provided by U-Boot; it is expected that (if they behave
3205 well) you can continue to work in U-Boot after return from
3206 the Standalone Program.
3207 "OS Kernel Images" are usually images of some Embedded OS which
3208 will take over control completely. Usually these programs
3209 will install their own set of exception handlers, device
3210 drivers, set up the MMU, etc. - this means, that you cannot
3211 expect to re-enter U-Boot except by resetting the CPU.
3212 "RAMDisk Images" are more or less just data blocks, and their
3213 parameters (address, size) are passed to an OS kernel that is
3215 "Multi-File Images" contain several images, typically an OS
3216 (Linux) kernel image and one or more data images like
3217 RAMDisks. This construct is useful for instance when you want
3218 to boot over the network using BOOTP etc., where the boot
3219 server provides just a single image file, but you want to get
3220 for instance an OS kernel and a RAMDisk image.
3222 "Multi-File Images" start with a list of image sizes, each
3223 image size (in bytes) specified by an "uint32_t" in network
3224 byte order. This list is terminated by an "(uint32_t)0".
3225 Immediately after the terminating 0 follow the images, one by
3226 one, all aligned on "uint32_t" boundaries (size rounded up to
3227 a multiple of 4 bytes).
3229 "Firmware Images" are binary images containing firmware (like
3230 U-Boot or FPGA images) which usually will be programmed to
3233 "Script files" are command sequences that will be executed by
3234 U-Boot's command interpreter; this feature is especially
3235 useful when you configure U-Boot to use a real shell (hush)
3236 as command interpreter.
3242 One of the features of U-Boot is that you can dynamically load and
3243 run "standalone" applications, which can use some resources of
3244 U-Boot like console I/O functions or interrupt services.
3246 Two simple examples are included with the sources:
3251 'examples/hello_world.c' contains a small "Hello World" Demo
3252 application; it is automatically compiled when you build U-Boot.
3253 It's configured to run at address 0x00040004, so you can play with it
3257 ## Ready for S-Record download ...
3258 ~>examples/hello_world.srec
3259 1 2 3 4 5 6 7 8 9 10 11 ...
3260 [file transfer complete]
3262 ## Start Addr = 0x00040004
3264 => go 40004 Hello World! This is a test.
3265 ## Starting application at 0x00040004 ...
3276 Hit any key to exit ...
3278 ## Application terminated, rc = 0x0
3280 Another example, which demonstrates how to register a CPM interrupt
3281 handler with the U-Boot code, can be found in 'examples/timer.c'.
3282 Here, a CPM timer is set up to generate an interrupt every second.
3283 The interrupt service routine is trivial, just printing a '.'
3284 character, but this is just a demo program. The application can be
3285 controlled by the following keys:
3287 ? - print current values og the CPM Timer registers
3288 b - enable interrupts and start timer
3289 e - stop timer and disable interrupts
3290 q - quit application
3293 ## Ready for S-Record download ...
3294 ~>examples/timer.srec
3295 1 2 3 4 5 6 7 8 9 10 11 ...
3296 [file transfer complete]
3298 ## Start Addr = 0x00040004
3301 ## Starting application at 0x00040004 ...
3304 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3307 [q, b, e, ?] Set interval 1000000 us
3310 [q, b, e, ?] ........
3311 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3314 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3317 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3320 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3322 [q, b, e, ?] ...Stopping timer
3324 [q, b, e, ?] ## Application terminated, rc = 0x0
3330 Over time, many people have reported problems when trying to use the
3331 "minicom" terminal emulation program for serial download. I (wd)
3332 consider minicom to be broken, and recommend not to use it. Under
3333 Unix, I recommend to use C-Kermit for general purpose use (and
3334 especially for kermit binary protocol download ("loadb" command), and
3335 use "cu" for S-Record download ("loads" command).
3337 Nevertheless, if you absolutely want to use it try adding this
3338 configuration to your "File transfer protocols" section:
3340 Name Program Name U/D FullScr IO-Red. Multi
3341 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3342 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3348 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3349 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3351 Building requires a cross environment; it is known to work on
3352 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3353 need gmake since the Makefiles are not compatible with BSD make).
3354 Note that the cross-powerpc package does not install include files;
3355 attempting to build U-Boot will fail because <machine/ansi.h> is
3356 missing. This file has to be installed and patched manually:
3358 # cd /usr/pkg/cross/powerpc-netbsd/include
3360 # ln -s powerpc machine
3361 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3362 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3364 Native builds *don't* work due to incompatibilities between native
3365 and U-Boot include files.
3367 Booting assumes that (the first part of) the image booted is a
3368 stage-2 loader which in turn loads and then invokes the kernel
3369 proper. Loader sources will eventually appear in the NetBSD source
3370 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3371 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3374 Implementation Internals:
3375 =========================
3377 The following is not intended to be a complete description of every
3378 implementation detail. However, it should help to understand the
3379 inner workings of U-Boot and make it easier to port it to custom
3383 Initial Stack, Global Data:
3384 ---------------------------
3386 The implementation of U-Boot is complicated by the fact that U-Boot
3387 starts running out of ROM (flash memory), usually without access to
3388 system RAM (because the memory controller is not initialized yet).
3389 This means that we don't have writable Data or BSS segments, and BSS
3390 is not initialized as zero. To be able to get a C environment working
3391 at all, we have to allocate at least a minimal stack. Implementation
3392 options for this are defined and restricted by the CPU used: Some CPU
3393 models provide on-chip memory (like the IMMR area on MPC8xx and
3394 MPC826x processors), on others (parts of) the data cache can be
3395 locked as (mis-) used as memory, etc.
3397 Chris Hallinan posted a good summary of these issues to the
3398 u-boot-users mailing list:
3400 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3401 From: "Chris Hallinan" <clh@net1plus.com>
3402 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3405 Correct me if I'm wrong, folks, but the way I understand it
3406 is this: Using DCACHE as initial RAM for Stack, etc, does not
3407 require any physical RAM backing up the cache. The cleverness
3408 is that the cache is being used as a temporary supply of
3409 necessary storage before the SDRAM controller is setup. It's
3410 beyond the scope of this list to expain the details, but you
3411 can see how this works by studying the cache architecture and
3412 operation in the architecture and processor-specific manuals.
3414 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3415 is another option for the system designer to use as an
3416 initial stack/ram area prior to SDRAM being available. Either
3417 option should work for you. Using CS 4 should be fine if your
3418 board designers haven't used it for something that would
3419 cause you grief during the initial boot! It is frequently not
3422 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3423 with your processor/board/system design. The default value
3424 you will find in any recent u-boot distribution in
3425 walnut.h should work for you. I'd set it to a value larger
3426 than your SDRAM module. If you have a 64MB SDRAM module, set
3427 it above 400_0000. Just make sure your board has no resources
3428 that are supposed to respond to that address! That code in
3429 start.S has been around a while and should work as is when
3430 you get the config right.
3435 It is essential to remember this, since it has some impact on the C
3436 code for the initialization procedures:
3438 * Initialized global data (data segment) is read-only. Do not attempt
3441 * Do not use any unitialized global data (or implicitely initialized
3442 as zero data - BSS segment) at all - this is undefined, initiali-
3443 zation is performed later (when relocating to RAM).
3445 * Stack space is very limited. Avoid big data buffers or things like
3448 Having only the stack as writable memory limits means we cannot use
3449 normal global data to share information beween the code. But it
3450 turned out that the implementation of U-Boot can be greatly
3451 simplified by making a global data structure (gd_t) available to all
3452 functions. We could pass a pointer to this data as argument to _all_
3453 functions, but this would bloat the code. Instead we use a feature of
3454 the GCC compiler (Global Register Variables) to share the data: we
3455 place a pointer (gd) to the global data into a register which we
3456 reserve for this purpose.
3458 When choosing a register for such a purpose we are restricted by the
3459 relevant (E)ABI specifications for the current architecture, and by
3460 GCC's implementation.
3462 For PowerPC, the following registers have specific use:
3465 R3-R4: parameter passing and return values
3466 R5-R10: parameter passing
3467 R13: small data area pointer
3471 (U-Boot also uses R14 as internal GOT pointer.)
3473 ==> U-Boot will use R29 to hold a pointer to the global data
3475 Note: on PPC, we could use a static initializer (since the
3476 address of the global data structure is known at compile time),
3477 but it turned out that reserving a register results in somewhat
3478 smaller code - although the code savings are not that big (on
3479 average for all boards 752 bytes for the whole U-Boot image,
3480 624 text + 127 data).
3482 On ARM, the following registers are used:
3484 R0: function argument word/integer result
3485 R1-R3: function argument word
3487 R10: stack limit (used only if stack checking if enabled)
3488 R11: argument (frame) pointer
3489 R12: temporary workspace
3492 R15: program counter
3494 ==> U-Boot will use R8 to hold a pointer to the global data
3496 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3497 or current versions of GCC may "optimize" the code too much.
3502 U-Boot runs in system state and uses physical addresses, i.e. the
3503 MMU is not used either for address mapping nor for memory protection.
3505 The available memory is mapped to fixed addresses using the memory
3506 controller. In this process, a contiguous block is formed for each
3507 memory type (Flash, SDRAM, SRAM), even when it consists of several
3508 physical memory banks.
3510 U-Boot is installed in the first 128 kB of the first Flash bank (on
3511 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3512 booting and sizing and initializing DRAM, the code relocates itself
3513 to the upper end of DRAM. Immediately below the U-Boot code some
3514 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3515 configuration setting]. Below that, a structure with global Board
3516 Info data is placed, followed by the stack (growing downward).
3518 Additionally, some exception handler code is copied to the low 8 kB
3519 of DRAM (0x00000000 ... 0x00001FFF).
3521 So a typical memory configuration with 16 MB of DRAM could look like
3524 0x0000 0000 Exception Vector code
3527 0x0000 2000 Free for Application Use
3533 0x00FB FF20 Monitor Stack (Growing downward)
3534 0x00FB FFAC Board Info Data and permanent copy of global data
3535 0x00FC 0000 Malloc Arena
3538 0x00FE 0000 RAM Copy of Monitor Code
3539 ... eventually: LCD or video framebuffer
3540 ... eventually: pRAM (Protected RAM - unchanged by reset)
3541 0x00FF FFFF [End of RAM]
3544 System Initialization:
3545 ----------------------
3547 In the reset configuration, U-Boot starts at the reset entry point
3548 (on most PowerPC systens at address 0x00000100). Because of the reset
3549 configuration for CS0# this is a mirror of the onboard Flash memory.
3550 To be able to re-map memory U-Boot then jumps to its link address.
3551 To be able to implement the initialization code in C, a (small!)
3552 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3553 which provide such a feature like MPC8xx or MPC8260), or in a locked
3554 part of the data cache. After that, U-Boot initializes the CPU core,
3555 the caches and the SIU.
3557 Next, all (potentially) available memory banks are mapped using a
3558 preliminary mapping. For example, we put them on 512 MB boundaries
3559 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3560 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3561 programmed for SDRAM access. Using the temporary configuration, a
3562 simple memory test is run that determines the size of the SDRAM
3565 When there is more than one SDRAM bank, and the banks are of
3566 different size, the largest is mapped first. For equal size, the first
3567 bank (CS2#) is mapped first. The first mapping is always for address
3568 0x00000000, with any additional banks following immediately to create
3569 contiguous memory starting from 0.
3571 Then, the monitor installs itself at the upper end of the SDRAM area
3572 and allocates memory for use by malloc() and for the global Board
3573 Info data; also, the exception vector code is copied to the low RAM
3574 pages, and the final stack is set up.
3576 Only after this relocation will you have a "normal" C environment;
3577 until that you are restricted in several ways, mostly because you are
3578 running from ROM, and because the code will have to be relocated to a
3582 U-Boot Porting Guide:
3583 ----------------------
3585 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3589 int main (int argc, char *argv[])
3591 sighandler_t no_more_time;
3593 signal (SIGALRM, no_more_time);
3594 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3596 if (available_money > available_manpower) {
3597 pay consultant to port U-Boot;
3601 Download latest U-Boot source;
3603 Subscribe to u-boot-users mailing list;
3606 email ("Hi, I am new to U-Boot, how do I get started?");
3610 Read the README file in the top level directory;
3611 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3612 Read the source, Luke;
3615 if (available_money > toLocalCurrency ($2500)) {
3618 Add a lot of aggravation and time;
3621 Create your own board support subdirectory;
3623 Create your own board config file;
3627 Add / modify source code;
3631 email ("Hi, I am having problems...");
3633 Send patch file to Wolfgang;
3638 void no_more_time (int sig)
3647 All contributions to U-Boot should conform to the Linux kernel
3648 coding style; see the file "Documentation/CodingStyle" and the script
3649 "scripts/Lindent" in your Linux kernel source directory. In sources
3650 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3651 spaces before parameters to function calls) is actually used.
3653 Source files originating from a different project (for example the
3654 MTD subsystem) are generally exempt from these guidelines and are not
3655 reformated to ease subsequent migration to newer versions of those
3658 Please note that U-Boot is implemented in C (and to some small parts in
3659 Assembler); no C++ is used, so please do not use C++ style comments (//)
3662 Please also stick to the following formatting rules:
3663 - remove any trailing white space
3664 - use TAB characters for indentation, not spaces
3665 - make sure NOT to use DOS '\r\n' line feeds
3666 - do not add more than 2 empty lines to source files
3667 - do not add trailing empty lines to source files
3669 Submissions which do not conform to the standards may be returned
3670 with a request to reformat the changes.
3676 Since the number of patches for U-Boot is growing, we need to
3677 establish some rules. Submissions which do not conform to these rules
3678 may be rejected, even when they contain important and valuable stuff.
3680 Patches shall be sent to the u-boot-users mailing list.
3682 When you send a patch, please include the following information with
3685 * For bug fixes: a description of the bug and how your patch fixes
3686 this bug. Please try to include a way of demonstrating that the
3687 patch actually fixes something.
3689 * For new features: a description of the feature and your
3692 * A CHANGELOG entry as plaintext (separate from the patch)
3694 * For major contributions, your entry to the CREDITS file
3696 * When you add support for a new board, don't forget to add this
3697 board to the MAKEALL script, too.
3699 * If your patch adds new configuration options, don't forget to
3700 document these in the README file.
3702 * The patch itself. If you are accessing the CVS repository use "cvs
3703 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3704 version of diff does not support these options, then get the latest
3705 version of GNU diff.
3707 The current directory when running this command shall be the top
3708 level directory of the U-Boot source tree, or it's parent directory
3709 (i. e. please make sure that your patch includes sufficient
3710 directory information for the affected files).
3712 We accept patches as plain text, MIME attachments or as uuencoded
3715 * If one logical set of modifications affects or creates several
3716 files, all these changes shall be submitted in a SINGLE patch file.
3718 * Changesets that contain different, unrelated modifications shall be
3719 submitted as SEPARATE patches, one patch per changeset.
3724 * Before sending the patch, run the MAKEALL script on your patched
3725 source tree and make sure that no errors or warnings are reported
3726 for any of the boards.
3728 * Keep your modifications to the necessary minimum: A patch
3729 containing several unrelated changes or arbitrary reformats will be
3730 returned with a request to re-formatting / split it.
3732 * If you modify existing code, make sure that your new code does not
3733 add to the memory footprint of the code ;-) Small is beautiful!
3734 When adding new features, these should compile conditionally only
3735 (using #ifdef), and the resulting code with the new feature
3736 disabled must not need more memory than the old code without your
3739 * Remember that there is a size limit of 40 kB per message on the
3740 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob