2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
140 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
141 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
142 - mips Files specific to MIPS CPUs
143 - mpc5xx Files specific to Freescale MPC5xx CPUs
144 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
145 - mpc8xx Files specific to Freescale MPC8xx CPUs
146 - mpc8220 Files specific to Freescale MPC8220 CPUs
147 - mpc824x Files specific to Freescale MPC824x CPUs
148 - mpc8260 Files specific to Freescale MPC8260 CPUs
149 - mpc85xx Files specific to Freescale MPC85xx CPUs
150 - nios Files specific to Altera NIOS CPUs
151 - nios2 Files specific to Altera Nios-II CPUs
152 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
153 - pxa Files specific to Intel XScale PXA CPUs
154 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
155 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
156 - disk Code for disk drive partition handling
157 - doc Documentation (don't expect too much)
158 - drivers Commonly used device drivers
159 - dtt Digital Thermometer and Thermostat drivers
160 - examples Example code for standalone applications, etc.
161 - include Header Files
162 - lib_arm Files generic to ARM architecture
163 - lib_avr32 Files generic to AVR32 architecture
164 - lib_generic Files generic to all architectures
165 - lib_i386 Files generic to i386 architecture
166 - lib_m68k Files generic to m68k architecture
167 - lib_mips Files generic to MIPS architecture
168 - lib_nios Files generic to NIOS architecture
169 - lib_ppc Files generic to PowerPC architecture
170 - libfdt Library files to support flattened device trees
171 - net Networking code
172 - post Power On Self Test
173 - rtc Real Time Clock drivers
174 - tools Tools to build S-Record or U-Boot images, etc.
176 Software Configuration:
177 =======================
179 Configuration is usually done using C preprocessor defines; the
180 rationale behind that is to avoid dead code whenever possible.
182 There are two classes of configuration variables:
184 * Configuration _OPTIONS_:
185 These are selectable by the user and have names beginning with
188 * Configuration _SETTINGS_:
189 These depend on the hardware etc. and should not be meddled with if
190 you don't know what you're doing; they have names beginning with
193 Later we will add a configuration tool - probably similar to or even
194 identical to what's used for the Linux kernel. Right now, we have to
195 do the configuration by hand, which means creating some symbolic
196 links and editing some configuration files. We use the TQM8xxL boards
200 Selection of Processor Architecture and Board Type:
201 ---------------------------------------------------
203 For all supported boards there are ready-to-use default
204 configurations available; just type "make <board_name>_config".
206 Example: For a TQM823L module type:
211 For the Cogent platform, you need to specify the cpu type as well;
212 e.g. "make cogent_mpc8xx_config". And also configure the cogent
213 directory according to the instructions in cogent/README.
216 Configuration Options:
217 ----------------------
219 Configuration depends on the combination of board and CPU type; all
220 such information is kept in a configuration file
221 "include/configs/<board_name>.h".
223 Example: For a TQM823L module, all configuration settings are in
224 "include/configs/TQM823L.h".
227 Many of the options are named exactly as the corresponding Linux
228 kernel configuration options. The intention is to make it easier to
229 build a config tool - later.
232 The following options need to be configured:
234 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
236 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
238 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
239 Define exactly one, e.g. CONFIG_ATSTK1002
241 - CPU Module Type: (if CONFIG_COGENT is defined)
242 Define exactly one of
244 --- FIXME --- not tested yet:
245 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
246 CONFIG_CMA287_23, CONFIG_CMA287_50
248 - Motherboard Type: (if CONFIG_COGENT is defined)
249 Define exactly one of
250 CONFIG_CMA101, CONFIG_CMA102
252 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
253 Define one or more of
256 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
257 Define one or more of
258 CONFIG_LCD_HEARTBEAT - update a character position on
259 the lcd display every second with
262 - Board flavour: (if CONFIG_MPC8260ADS is defined)
265 CFG_8260ADS - original MPC8260ADS
266 CFG_8266ADS - MPC8266ADS
267 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
268 CFG_8272ADS - MPC8272ADS
270 - MPC824X Family Member (if CONFIG_MPC824X is defined)
271 Define exactly one of
272 CONFIG_MPC8240, CONFIG_MPC8245
274 - 8xx CPU Options: (if using an MPC8xx cpu)
275 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
276 get_gclk_freq() cannot work
277 e.g. if there is no 32KHz
278 reference PIT/RTC clock
279 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
282 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
285 CONFIG_8xx_CPUCLK_DEFAULT
286 See doc/README.MPC866
290 Define this to measure the actual CPU clock instead
291 of relying on the correctness of the configured
292 values. Mostly useful for board bringup to make sure
293 the PLL is locked at the intended frequency. Note
294 that this requires a (stable) reference clock (32 kHz
295 RTC clock or CFG_8XX_XIN)
297 - Intel Monahans options:
298 CFG_MONAHANS_RUN_MODE_OSC_RATIO
300 Defines the Monahans run mode to oscillator
301 ratio. Valid values are 8, 16, 24, 31. The core
302 frequency is this value multiplied by 13 MHz.
304 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
306 Defines the Monahans turbo mode to oscillator
307 ratio. Valid values are 1 (default if undefined) and
308 2. The core frequency as calculated above is multiplied
311 - Linux Kernel Interface:
314 U-Boot stores all clock information in Hz
315 internally. For binary compatibility with older Linux
316 kernels (which expect the clocks passed in the
317 bd_info data to be in MHz) the environment variable
318 "clocks_in_mhz" can be defined so that U-Boot
319 converts clock data to MHZ before passing it to the
321 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
322 "clocks_in_mhz=1" is automatically included in the
325 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
327 When transfering memsize parameter to linux, some versions
328 expect it to be in bytes, others in MB.
329 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
331 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
333 New kernel versions are expecting firmware settings to be
334 passed using flattened device trees (based on open firmware
338 * New libfdt-based support
339 * Adds the "fdt" command
340 * The bootm command automatically updates the fdt
343 * Deprecated, see CONFIG_OF_LIBFDT
344 * Original ft_build.c-based support
345 * Automatically modifies the dft as part of the bootm command
346 * The environment variable "disable_of", when set,
347 disables this functionality.
349 OF_CPU - The proper name of the cpus node.
350 OF_SOC - The proper name of the soc node.
351 OF_TBCLK - The timebase frequency.
352 OF_STDOUT_PATH - The path to the console device
354 boards with QUICC Engines require OF_QE to set UCC mac addresses
358 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
359 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
360 will have a copy of the bd_t. Space should be
361 pre-allocated in the dts for the bd_t.
363 CONFIG_OF_HAS_UBOOT_ENV
365 * CONFIG_OF_LIBFDT - enables the "fdt env" command
366 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
367 will have a copy of u-boot's environment variables
369 CONFIG_OF_BOARD_SETUP
371 Board code has addition modification that it wants to make
372 to the flat device tree before handing it off to the kernel
376 This define fills in the correct boot cpu in the boot
377 param header, the default value is zero if undefined.
382 Define this if you want support for Amba PrimeCell PL010 UARTs.
386 Define this if you want support for Amba PrimeCell PL011 UARTs.
390 If you have Amba PrimeCell PL011 UARTs, set this variable to
391 the clock speed of the UARTs.
395 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
396 define this to a list of base addresses for each (supported)
397 port. See e.g. include/configs/versatile.h
401 Depending on board, define exactly one serial port
402 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
403 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
404 console by defining CONFIG_8xx_CONS_NONE
406 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
407 port routines must be defined elsewhere
408 (i.e. serial_init(), serial_getc(), ...)
411 Enables console device for a color framebuffer. Needs following
412 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
413 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
415 VIDEO_HW_RECTFILL graphic chip supports
418 VIDEO_HW_BITBLT graphic chip supports
419 bit-blit (cf. smiLynxEM)
420 VIDEO_VISIBLE_COLS visible pixel columns
422 VIDEO_VISIBLE_ROWS visible pixel rows
423 VIDEO_PIXEL_SIZE bytes per pixel
424 VIDEO_DATA_FORMAT graphic data format
425 (0-5, cf. cfb_console.c)
426 VIDEO_FB_ADRS framebuffer address
427 VIDEO_KBD_INIT_FCT keyboard int fct
428 (i.e. i8042_kbd_init())
429 VIDEO_TSTC_FCT test char fct
431 VIDEO_GETC_FCT get char fct
433 CONFIG_CONSOLE_CURSOR cursor drawing on/off
434 (requires blink timer
436 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
437 CONFIG_CONSOLE_TIME display time/date info in
439 (requires CONFIG_CMD_DATE)
440 CONFIG_VIDEO_LOGO display Linux logo in
442 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
443 linux_logo.h for logo.
444 Requires CONFIG_VIDEO_LOGO
445 CONFIG_CONSOLE_EXTRA_INFO
446 addional board info beside
449 When CONFIG_CFB_CONSOLE is defined, video console is
450 default i/o. Serial console can be forced with
451 environment 'console=serial'.
453 When CONFIG_SILENT_CONSOLE is defined, all console
454 messages (by U-Boot and Linux!) can be silenced with
455 the "silent" environment variable. See
456 doc/README.silent for more information.
459 CONFIG_BAUDRATE - in bps
460 Select one of the baudrates listed in
461 CFG_BAUDRATE_TABLE, see below.
462 CFG_BRGCLK_PRESCALE, baudrate prescale
464 - Interrupt driven serial port input:
465 CONFIG_SERIAL_SOFTWARE_FIFO
468 Use an interrupt handler for receiving data on the
469 serial port. It also enables using hardware handshake
470 (RTS/CTS) and UART's built-in FIFO. Set the number of
471 bytes the interrupt driven input buffer should have.
473 Leave undefined to disable this feature, including
474 disable the buffer and hardware handshake.
476 - Console UART Number:
480 If defined internal UART1 (and not UART0) is used
481 as default U-Boot console.
483 - Boot Delay: CONFIG_BOOTDELAY - in seconds
484 Delay before automatically booting the default image;
485 set to -1 to disable autoboot.
487 See doc/README.autoboot for these options that
488 work with CONFIG_BOOTDELAY. None are required.
489 CONFIG_BOOT_RETRY_TIME
490 CONFIG_BOOT_RETRY_MIN
491 CONFIG_AUTOBOOT_KEYED
492 CONFIG_AUTOBOOT_PROMPT
493 CONFIG_AUTOBOOT_DELAY_STR
494 CONFIG_AUTOBOOT_STOP_STR
495 CONFIG_AUTOBOOT_DELAY_STR2
496 CONFIG_AUTOBOOT_STOP_STR2
497 CONFIG_ZERO_BOOTDELAY_CHECK
498 CONFIG_RESET_TO_RETRY
502 Only needed when CONFIG_BOOTDELAY is enabled;
503 define a command string that is automatically executed
504 when no character is read on the console interface
505 within "Boot Delay" after reset.
508 This can be used to pass arguments to the bootm
509 command. The value of CONFIG_BOOTARGS goes into the
510 environment value "bootargs".
512 CONFIG_RAMBOOT and CONFIG_NFSBOOT
513 The value of these goes into the environment as
514 "ramboot" and "nfsboot" respectively, and can be used
515 as a convenience, when switching between booting from
521 When this option is #defined, the existence of the
522 environment variable "preboot" will be checked
523 immediately before starting the CONFIG_BOOTDELAY
524 countdown and/or running the auto-boot command resp.
525 entering interactive mode.
527 This feature is especially useful when "preboot" is
528 automatically generated or modified. For an example
529 see the LWMON board specific code: here "preboot" is
530 modified when the user holds down a certain
531 combination of keys on the (special) keyboard when
534 - Serial Download Echo Mode:
536 If defined to 1, all characters received during a
537 serial download (using the "loads" command) are
538 echoed back. This might be needed by some terminal
539 emulations (like "cu"), but may as well just take
540 time on others. This setting #define's the initial
541 value of the "loads_echo" environment variable.
543 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
545 Select one of the baudrates listed in
546 CFG_BAUDRATE_TABLE, see below.
549 Monitor commands can be included or excluded
550 from the build by using the #include files
551 "config_cmd_all.h" and #undef'ing unwanted
552 commands, or using "config_cmd_default.h"
553 and augmenting with additional #define's
556 The default command configuration includes all commands
557 except those marked below with a "*".
559 CONFIG_CMD_ASKENV * ask for env variable
560 CONFIG_CMD_AUTOSCRIPT Autoscript Support
561 CONFIG_CMD_BDI bdinfo
562 CONFIG_CMD_BEDBUG * Include BedBug Debugger
563 CONFIG_CMD_BMP * BMP support
564 CONFIG_CMD_BSP * Board specific commands
565 CONFIG_CMD_BOOTD bootd
566 CONFIG_CMD_CACHE * icache, dcache
567 CONFIG_CMD_CONSOLE coninfo
568 CONFIG_CMD_DATE * support for RTC, date/time...
569 CONFIG_CMD_DHCP * DHCP support
570 CONFIG_CMD_DIAG * Diagnostics
571 CONFIG_CMD_DOC * Disk-On-Chip Support
572 CONFIG_CMD_DTT * Digital Therm and Thermostat
573 CONFIG_CMD_ECHO echo arguments
574 CONFIG_CMD_EEPROM * EEPROM read/write support
575 CONFIG_CMD_ELF * bootelf, bootvx
576 CONFIG_CMD_ENV saveenv
577 CONFIG_CMD_FDC * Floppy Disk Support
578 CONFIG_CMD_FAT * FAT partition support
579 CONFIG_CMD_FDOS * Dos diskette Support
580 CONFIG_CMD_FLASH flinfo, erase, protect
581 CONFIG_CMD_FPGA FPGA device initialization support
582 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
583 CONFIG_CMD_I2C * I2C serial bus support
584 CONFIG_CMD_IDE * IDE harddisk support
585 CONFIG_CMD_IMI iminfo
586 CONFIG_CMD_IMLS List all found images
587 CONFIG_CMD_IMMAP * IMMR dump support
588 CONFIG_CMD_IRQ * irqinfo
589 CONFIG_CMD_ITEST Integer/string test of 2 values
590 CONFIG_CMD_JFFS2 * JFFS2 Support
591 CONFIG_CMD_KGDB * kgdb
592 CONFIG_CMD_LOADB loadb
593 CONFIG_CMD_LOADS loads
594 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
596 CONFIG_CMD_MISC Misc functions like sleep etc
597 CONFIG_CMD_MMC * MMC memory mapped support
598 CONFIG_CMD_MII * MII utility commands
599 CONFIG_CMD_NAND * NAND support
600 CONFIG_CMD_NET bootp, tftpboot, rarpboot
601 CONFIG_CMD_PCI * pciinfo
602 CONFIG_CMD_PCMCIA * PCMCIA support
603 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
605 CONFIG_CMD_PORTIO * Port I/O
606 CONFIG_CMD_REGINFO * Register dump
607 CONFIG_CMD_RUN run command in env variable
608 CONFIG_CMD_SAVES * save S record dump
609 CONFIG_CMD_SCSI * SCSI Support
610 CONFIG_CMD_SDRAM * print SDRAM configuration information
611 (requires CONFIG_CMD_I2C)
612 CONFIG_CMD_SETGETDCR Support for DCR Register access
614 CONFIG_CMD_SPI * SPI serial bus support
615 CONFIG_CMD_USB * USB support
616 CONFIG_CMD_VFD * VFD support (TRAB)
617 CONFIG_CMD_BSP * Board SPecific functions
618 CONFIG_CMD_CDP * Cisco Discover Protocol support
619 CONFIG_CMD_FSL * Microblaze FSL support
622 EXAMPLE: If you want all functions except of network
623 support you can write:
625 #include "config_cmd_all.h"
626 #undef CONFIG_CMD_NET
629 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
631 Note: Don't enable the "icache" and "dcache" commands
632 (configuration option CONFIG_CMD_CACHE) unless you know
633 what you (and your U-Boot users) are doing. Data
634 cache cannot be enabled on systems like the 8xx or
635 8260 (where accesses to the IMMR region must be
636 uncached), and it cannot be disabled on all other
637 systems where we (mis-) use the data cache to hold an
638 initial stack and some data.
641 XXX - this list needs to get updated!
645 If this variable is defined, it enables watchdog
646 support. There must be support in the platform specific
647 code for a watchdog. For the 8xx and 8260 CPUs, the
648 SIU Watchdog feature is enabled in the SYPCR
652 CONFIG_VERSION_VARIABLE
653 If this variable is defined, an environment variable
654 named "ver" is created by U-Boot showing the U-Boot
655 version as printed by the "version" command.
656 This variable is readonly.
660 When CONFIG_CMD_DATE is selected, the type of the RTC
661 has to be selected, too. Define exactly one of the
664 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
665 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
666 CONFIG_RTC_MC146818 - use MC146818 RTC
667 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
668 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
669 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
670 CONFIG_RTC_DS164x - use Dallas DS164x RTC
671 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
673 Note that if the RTC uses I2C, then the I2C interface
674 must also be configured. See I2C Support, below.
678 When CONFIG_TIMESTAMP is selected, the timestamp
679 (date and time) of an image is printed by image
680 commands like bootm or iminfo. This option is
681 automatically enabled when you select CONFIG_CMD_DATE .
684 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
685 and/or CONFIG_ISO_PARTITION
687 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
688 CONFIG_CMD_SCSI) you must configure support for at least
689 one partition type as well.
692 CONFIG_IDE_RESET_ROUTINE - this is defined in several
693 board configurations files but used nowhere!
695 CONFIG_IDE_RESET - is this is defined, IDE Reset will
696 be performed by calling the function
697 ide_set_reset(int reset)
698 which has to be defined in a board specific file
703 Set this to enable ATAPI support.
708 Set this to enable support for disks larger than 137GB
709 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
710 Whithout these , LBA48 support uses 32bit variables and will 'only'
711 support disks up to 2.1TB.
714 When enabled, makes the IDE subsystem use 64bit sector addresses.
718 At the moment only there is only support for the
719 SYM53C8XX SCSI controller; define
720 CONFIG_SCSI_SYM53C8XX to enable it.
722 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
723 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
724 CFG_SCSI_MAX_LUN] can be adjusted to define the
725 maximum numbers of LUNs, SCSI ID's and target
727 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
729 - NETWORK Support (PCI):
731 Support for Intel 8254x gigabit chips.
734 Support for Intel 82557/82559/82559ER chips.
735 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
736 write routine for first time initialisation.
739 Support for Digital 2114x chips.
740 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
741 modem chip initialisation (KS8761/QS6611).
744 Support for National dp83815 chips.
747 Support for National dp8382[01] gigabit chips.
749 - NETWORK Support (other):
751 CONFIG_DRIVER_LAN91C96
752 Support for SMSC's LAN91C96 chips.
755 Define this to hold the physical address
756 of the LAN91C96's I/O space
758 CONFIG_LAN91C96_USE_32_BIT
759 Define this to enable 32 bit addressing
761 CONFIG_DRIVER_SMC91111
762 Support for SMSC's LAN91C111 chip
765 Define this to hold the physical address
766 of the device (I/O space)
768 CONFIG_SMC_USE_32_BIT
769 Define this if data bus is 32 bits
771 CONFIG_SMC_USE_IOFUNCS
772 Define this to use i/o functions instead of macros
773 (some hardware wont work with macros)
776 At the moment only the UHCI host controller is
777 supported (PIP405, MIP405, MPC5200); define
778 CONFIG_USB_UHCI to enable it.
779 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
780 and define CONFIG_USB_STORAGE to enable the USB
783 Supported are USB Keyboards and USB Floppy drives
785 MPC5200 USB requires additional defines:
787 for 528 MHz Clock: 0x0001bbbb
789 for differential drivers: 0x00001000
790 for single ended drivers: 0x00005000
792 May be defined to allow interrupt polling
793 instead of using asynchronous interrupts
796 Define the below if you wish to use the USB console.
797 Once firmware is rebuilt from a serial console issue the
798 command "setenv stdin usbtty; setenv stdout usbtty" and
799 attach your usb cable. The Unix command "dmesg" should print
800 it has found a new device. The environment variable usbtty
801 can be set to gserial or cdc_acm to enable your device to
802 appear to a USB host as a Linux gserial device or a
803 Common Device Class Abstract Control Model serial device.
804 If you select usbtty = gserial you should be able to enumerate
806 # modprobe usbserial vendor=0xVendorID product=0xProductID
807 else if using cdc_acm, simply setting the environment
808 variable usbtty to be cdc_acm should suffice. The following
809 might be defined in YourBoardName.h
812 Define this to build a UDC device
815 Define this to have a tty type of device available to
816 talk to the UDC device
818 CFG_CONSOLE_IS_IN_ENV
819 Define this if you want stdin, stdout &/or stderr to
823 CFG_USB_EXTC_CLK 0xBLAH
824 Derive USB clock from external clock "blah"
825 - CFG_USB_EXTC_CLK 0x02
827 CFG_USB_BRG_CLK 0xBLAH
828 Derive USB clock from brgclk
829 - CFG_USB_BRG_CLK 0x04
831 If you have a USB-IF assigned VendorID then you may wish to
832 define your own vendor specific values either in BoardName.h
833 or directly in usbd_vendor_info.h. If you don't define
834 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
835 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
836 should pretend to be a Linux device to it's target host.
838 CONFIG_USBD_MANUFACTURER
839 Define this string as the name of your company for
840 - CONFIG_USBD_MANUFACTURER "my company"
842 CONFIG_USBD_PRODUCT_NAME
843 Define this string as the name of your product
844 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
847 Define this as your assigned Vendor ID from the USB
848 Implementors Forum. This *must* be a genuine Vendor ID
849 to avoid polluting the USB namespace.
850 - CONFIG_USBD_VENDORID 0xFFFF
852 CONFIG_USBD_PRODUCTID
853 Define this as the unique Product ID
855 - CONFIG_USBD_PRODUCTID 0xFFFF
859 The MMC controller on the Intel PXA is supported. To
860 enable this define CONFIG_MMC. The MMC can be
861 accessed from the boot prompt by mapping the device
862 to physical memory similar to flash. Command line is
863 enabled with CONFIG_CMD_MMC. The MMC driver also works with
864 the FAT fs. This is enabled with CONFIG_CMD_FAT.
866 - Journaling Flash filesystem support:
867 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
868 CONFIG_JFFS2_NAND_DEV
869 Define these for a default partition on a NAND device
871 CFG_JFFS2_FIRST_SECTOR,
872 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
873 Define these for a default partition on a NOR device
876 Define this to create an own partition. You have to provide a
877 function struct part_info* jffs2_part_info(int part_num)
879 If you define only one JFFS2 partition you may also want to
880 #define CFG_JFFS_SINGLE_PART 1
881 to disable the command chpart. This is the default when you
882 have not defined a custom partition
887 Define this to enable standard (PC-Style) keyboard
891 Standard PC keyboard driver with US (is default) and
892 GERMAN key layout (switch via environment 'keymap=de') support.
893 Export function i8042_kbd_init, i8042_tstc and i8042_getc
894 for cfb_console. Supports cursor blinking.
899 Define this to enable video support (for output to
904 Enable Chips & Technologies 69000 Video chip
906 CONFIG_VIDEO_SMI_LYNXEM
907 Enable Silicon Motion SMI 712/710/810 Video chip. The
908 video output is selected via environment 'videoout'
909 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
912 For the CT69000 and SMI_LYNXEM drivers, videomode is
913 selected via environment 'videomode'. Two diferent ways
915 - "videomode=num" 'num' is a standard LiLo mode numbers.
916 Following standard modes are supported (* is default):
918 Colors 640x480 800x600 1024x768 1152x864 1280x1024
919 -------------+---------------------------------------------
920 8 bits | 0x301* 0x303 0x305 0x161 0x307
921 15 bits | 0x310 0x313 0x316 0x162 0x319
922 16 bits | 0x311 0x314 0x317 0x163 0x31A
923 24 bits | 0x312 0x315 0x318 ? 0x31B
924 -------------+---------------------------------------------
925 (i.e. setenv videomode 317; saveenv; reset;)
927 - "videomode=bootargs" all the video parameters are parsed
928 from the bootargs. (See drivers/video/videomodes.c)
931 CONFIG_VIDEO_SED13806
932 Enable Epson SED13806 driver. This driver supports 8bpp
933 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
934 or CONFIG_VIDEO_SED13806_16BPP
939 Define this to enable a custom keyboard support.
940 This simply calls drv_keyboard_init() which must be
941 defined in your board-specific files.
942 The only board using this so far is RBC823.
944 - LCD Support: CONFIG_LCD
946 Define this to enable LCD support (for output to LCD
947 display); also select one of the supported displays
948 by defining one of these:
950 CONFIG_NEC_NL6448AC33:
952 NEC NL6448AC33-18. Active, color, single scan.
954 CONFIG_NEC_NL6448BC20
956 NEC NL6448BC20-08. 6.5", 640x480.
957 Active, color, single scan.
959 CONFIG_NEC_NL6448BC33_54
961 NEC NL6448BC33-54. 10.4", 640x480.
962 Active, color, single scan.
966 Sharp 320x240. Active, color, single scan.
967 It isn't 16x9, and I am not sure what it is.
969 CONFIG_SHARP_LQ64D341
971 Sharp LQ64D341 display, 640x480.
972 Active, color, single scan.
976 HLD1045 display, 640x480.
977 Active, color, single scan.
981 Optrex CBL50840-2 NF-FW 99 22 M5
983 Hitachi LMG6912RPFC-00T
987 320x240. Black & white.
989 Normally display is black on white background; define
990 CFG_WHITE_ON_BLACK to get it inverted.
992 - Splash Screen Support: CONFIG_SPLASH_SCREEN
994 If this option is set, the environment is checked for
995 a variable "splashimage". If found, the usual display
996 of logo, copyright and system information on the LCD
997 is suppressed and the BMP image at the address
998 specified in "splashimage" is loaded instead. The
999 console is redirected to the "nulldev", too. This
1000 allows for a "silent" boot where a splash screen is
1001 loaded very quickly after power-on.
1003 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1005 If this option is set, additionally to standard BMP
1006 images, gzipped BMP images can be displayed via the
1007 splashscreen support or the bmp command.
1009 - Compression support:
1012 If this option is set, support for bzip2 compressed
1013 images is included. If not, only uncompressed and gzip
1014 compressed images are supported.
1016 NOTE: the bzip2 algorithm requires a lot of RAM, so
1017 the malloc area (as defined by CFG_MALLOC_LEN) should
1023 The address of PHY on MII bus.
1025 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1027 The clock frequency of the MII bus
1031 If this option is set, support for speed/duplex
1032 detection of Gigabit PHY is included.
1034 CONFIG_PHY_RESET_DELAY
1036 Some PHY like Intel LXT971A need extra delay after
1037 reset before any MII register access is possible.
1038 For such PHY, set this option to the usec delay
1039 required. (minimum 300usec for LXT971A)
1041 CONFIG_PHY_CMD_DELAY (ppc4xx)
1043 Some PHY like Intel LXT971A need extra delay after
1044 command issued before MII status register can be read
1051 Define a default value for ethernet address to use
1052 for the respective ethernet interface, in case this
1053 is not determined automatically.
1058 Define a default value for the IP address to use for
1059 the default ethernet interface, in case this is not
1060 determined through e.g. bootp.
1062 - Server IP address:
1065 Defines a default value for theIP address of a TFTP
1066 server to contact when using the "tftboot" command.
1068 - Multicast TFTP Mode:
1071 Defines whether you want to support multicast TFTP as per
1072 rfc-2090; for example to work with atftp. Lets lots of targets
1073 tftp down the same boot image concurrently. Note: the ethernet
1074 driver in use must provide a function: mcast() to join/leave a
1077 CONFIG_BOOTP_RANDOM_DELAY
1078 - BOOTP Recovery Mode:
1079 CONFIG_BOOTP_RANDOM_DELAY
1081 If you have many targets in a network that try to
1082 boot using BOOTP, you may want to avoid that all
1083 systems send out BOOTP requests at precisely the same
1084 moment (which would happen for instance at recovery
1085 from a power failure, when all systems will try to
1086 boot, thus flooding the BOOTP server. Defining
1087 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1088 inserted before sending out BOOTP requests. The
1089 following delays are inserted then:
1091 1st BOOTP request: delay 0 ... 1 sec
1092 2nd BOOTP request: delay 0 ... 2 sec
1093 3rd BOOTP request: delay 0 ... 4 sec
1095 BOOTP requests: delay 0 ... 8 sec
1097 - DHCP Advanced Options:
1098 You can fine tune the DHCP functionality by defining
1099 CONFIG_BOOTP_* symbols:
1101 CONFIG_BOOTP_SUBNETMASK
1102 CONFIG_BOOTP_GATEWAY
1103 CONFIG_BOOTP_HOSTNAME
1104 CONFIG_BOOTP_NISDOMAIN
1105 CONFIG_BOOTP_BOOTPATH
1106 CONFIG_BOOTP_BOOTFILESIZE
1109 CONFIG_BOOTP_SEND_HOSTNAME
1110 CONFIG_BOOTP_NTPSERVER
1111 CONFIG_BOOTP_TIMEOFFSET
1112 CONFIG_BOOTP_VENDOREX
1114 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1115 environment variable, not the BOOTP server.
1117 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1118 serverip from a DHCP server, it is possible that more
1119 than one DNS serverip is offered to the client.
1120 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1121 serverip will be stored in the additional environment
1122 variable "dnsip2". The first DNS serverip is always
1123 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1126 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1127 to do a dynamic update of a DNS server. To do this, they
1128 need the hostname of the DHCP requester.
1129 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1130 of the "hostname" environment variable is passed as
1131 option 12 to the DHCP server.
1134 CONFIG_CDP_DEVICE_ID
1136 The device id used in CDP trigger frames.
1138 CONFIG_CDP_DEVICE_ID_PREFIX
1140 A two character string which is prefixed to the MAC address
1145 A printf format string which contains the ascii name of
1146 the port. Normally is set to "eth%d" which sets
1147 eth0 for the first ethernet, eth1 for the second etc.
1149 CONFIG_CDP_CAPABILITIES
1151 A 32bit integer which indicates the device capabilities;
1152 0x00000010 for a normal host which does not forwards.
1156 An ascii string containing the version of the software.
1160 An ascii string containing the name of the platform.
1164 A 32bit integer sent on the trigger.
1166 CONFIG_CDP_POWER_CONSUMPTION
1168 A 16bit integer containing the power consumption of the
1169 device in .1 of milliwatts.
1171 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1173 A byte containing the id of the VLAN.
1175 - Status LED: CONFIG_STATUS_LED
1177 Several configurations allow to display the current
1178 status using a LED. For instance, the LED will blink
1179 fast while running U-Boot code, stop blinking as
1180 soon as a reply to a BOOTP request was received, and
1181 start blinking slow once the Linux kernel is running
1182 (supported by a status LED driver in the Linux
1183 kernel). Defining CONFIG_STATUS_LED enables this
1186 - CAN Support: CONFIG_CAN_DRIVER
1188 Defining CONFIG_CAN_DRIVER enables CAN driver support
1189 on those systems that support this (optional)
1190 feature, like the TQM8xxL modules.
1192 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1194 These enable I2C serial bus commands. Defining either of
1195 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1196 include the appropriate I2C driver for the selected cpu.
1198 This will allow you to use i2c commands at the u-boot
1199 command line (as long as you set CONFIG_CMD_I2C in
1200 CONFIG_COMMANDS) and communicate with i2c based realtime
1201 clock chips. See common/cmd_i2c.c for a description of the
1202 command line interface.
1204 CONFIG_I2C_CMD_TREE is a recommended option that places
1205 all I2C commands under a single 'i2c' root command. The
1206 older 'imm', 'imd', 'iprobe' etc. commands are considered
1207 deprecated and may disappear in the future.
1209 CONFIG_HARD_I2C selects a hardware I2C controller.
1211 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1212 bit-banging) driver instead of CPM or similar hardware
1215 There are several other quantities that must also be
1216 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1218 In both cases you will need to define CFG_I2C_SPEED
1219 to be the frequency (in Hz) at which you wish your i2c bus
1220 to run and CFG_I2C_SLAVE to be the address of this node (ie
1221 the cpu's i2c node address).
1223 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1224 sets the cpu up as a master node and so its address should
1225 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1226 p.16-473). So, set CFG_I2C_SLAVE to 0.
1228 That's all that's required for CONFIG_HARD_I2C.
1230 If you use the software i2c interface (CONFIG_SOFT_I2C)
1231 then the following macros need to be defined (examples are
1232 from include/configs/lwmon.h):
1236 (Optional). Any commands necessary to enable the I2C
1237 controller or configure ports.
1239 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1243 (Only for MPC8260 CPU). The I/O port to use (the code
1244 assumes both bits are on the same port). Valid values
1245 are 0..3 for ports A..D.
1249 The code necessary to make the I2C data line active
1250 (driven). If the data line is open collector, this
1253 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1257 The code necessary to make the I2C data line tri-stated
1258 (inactive). If the data line is open collector, this
1261 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1265 Code that returns TRUE if the I2C data line is high,
1268 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1272 If <bit> is TRUE, sets the I2C data line high. If it
1273 is FALSE, it clears it (low).
1275 eg: #define I2C_SDA(bit) \
1276 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1277 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1281 If <bit> is TRUE, sets the I2C clock line high. If it
1282 is FALSE, it clears it (low).
1284 eg: #define I2C_SCL(bit) \
1285 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1286 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1290 This delay is invoked four times per clock cycle so this
1291 controls the rate of data transfer. The data rate thus
1292 is 1 / (I2C_DELAY * 4). Often defined to be something
1295 #define I2C_DELAY udelay(2)
1299 When a board is reset during an i2c bus transfer
1300 chips might think that the current transfer is still
1301 in progress. On some boards it is possible to access
1302 the i2c SCLK line directly, either by using the
1303 processor pin as a GPIO or by having a second pin
1304 connected to the bus. If this option is defined a
1305 custom i2c_init_board() routine in boards/xxx/board.c
1306 is run early in the boot sequence.
1308 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1310 This option enables configuration of bi_iic_fast[] flags
1311 in u-boot bd_info structure based on u-boot environment
1312 variable "i2cfast". (see also i2cfast)
1314 CONFIG_I2C_MULTI_BUS
1316 This option allows the use of multiple I2C buses, each of which
1317 must have a controller. At any point in time, only one bus is
1318 active. To switch to a different bus, use the 'i2c dev' command.
1319 Note that bus numbering is zero-based.
1323 This option specifies a list of I2C devices that will be skipped
1324 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1325 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1326 pairs. Otherwise, specify a 1D array of device addresses
1329 #undef CONFIG_I2C_MULTI_BUS
1330 #define CFG_I2C_NOPROBES {0x50,0x68}
1332 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1334 #define CONFIG_I2C_MULTI_BUS
1335 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1337 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1341 If defined, then this indicates the I2C bus number for DDR SPD.
1342 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1346 If defined, then this indicates the I2C bus number for the RTC.
1347 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1351 If defined, then this indicates the I2C bus number for the DTT.
1352 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1356 Define this option if you want to use Freescale's I2C driver in
1357 drivers/i2c/fsl_i2c.c.
1360 - SPI Support: CONFIG_SPI
1362 Enables SPI driver (so far only tested with
1363 SPI EEPROM, also an instance works with Crystal A/D and
1364 D/As on the SACSng board)
1368 Enables extended (16-bit) SPI EEPROM addressing.
1369 (symmetrical to CONFIG_I2C_X)
1373 Enables a software (bit-bang) SPI driver rather than
1374 using hardware support. This is a general purpose
1375 driver that only requires three general I/O port pins
1376 (two outputs, one input) to function. If this is
1377 defined, the board configuration must define several
1378 SPI configuration items (port pins to use, etc). For
1379 an example, see include/configs/sacsng.h.
1381 - FPGA Support: CONFIG_FPGA
1383 Enables FPGA subsystem.
1385 CONFIG_FPGA_<vendor>
1387 Enables support for specific chip vendors.
1390 CONFIG_FPGA_<family>
1392 Enables support for FPGA family.
1393 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1397 Specify the number of FPGA devices to support.
1399 CFG_FPGA_PROG_FEEDBACK
1401 Enable printing of hash marks during FPGA configuration.
1405 Enable checks on FPGA configuration interface busy
1406 status by the configuration function. This option
1407 will require a board or device specific function to
1412 If defined, a function that provides delays in the FPGA
1413 configuration driver.
1415 CFG_FPGA_CHECK_CTRLC
1416 Allow Control-C to interrupt FPGA configuration
1418 CFG_FPGA_CHECK_ERROR
1420 Check for configuration errors during FPGA bitfile
1421 loading. For example, abort during Virtex II
1422 configuration if the INIT_B line goes low (which
1423 indicated a CRC error).
1427 Maximum time to wait for the INIT_B line to deassert
1428 after PROB_B has been deasserted during a Virtex II
1429 FPGA configuration sequence. The default time is 500
1434 Maximum time to wait for BUSY to deassert during
1435 Virtex II FPGA configuration. The default is 5 mS.
1437 CFG_FPGA_WAIT_CONFIG
1439 Time to wait after FPGA configuration. The default is
1442 - Configuration Management:
1445 If defined, this string will be added to the U-Boot
1446 version information (U_BOOT_VERSION)
1448 - Vendor Parameter Protection:
1450 U-Boot considers the values of the environment
1451 variables "serial#" (Board Serial Number) and
1452 "ethaddr" (Ethernet Address) to be parameters that
1453 are set once by the board vendor / manufacturer, and
1454 protects these variables from casual modification by
1455 the user. Once set, these variables are read-only,
1456 and write or delete attempts are rejected. You can
1457 change this behviour:
1459 If CONFIG_ENV_OVERWRITE is #defined in your config
1460 file, the write protection for vendor parameters is
1461 completely disabled. Anybody can change or delete
1464 Alternatively, if you #define _both_ CONFIG_ETHADDR
1465 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1466 ethernet address is installed in the environment,
1467 which can be changed exactly ONCE by the user. [The
1468 serial# is unaffected by this, i. e. it remains
1474 Define this variable to enable the reservation of
1475 "protected RAM", i. e. RAM which is not overwritten
1476 by U-Boot. Define CONFIG_PRAM to hold the number of
1477 kB you want to reserve for pRAM. You can overwrite
1478 this default value by defining an environment
1479 variable "pram" to the number of kB you want to
1480 reserve. Note that the board info structure will
1481 still show the full amount of RAM. If pRAM is
1482 reserved, a new environment variable "mem" will
1483 automatically be defined to hold the amount of
1484 remaining RAM in a form that can be passed as boot
1485 argument to Linux, for instance like that:
1487 setenv bootargs ... mem=\${mem}
1490 This way you can tell Linux not to use this memory,
1491 either, which results in a memory region that will
1492 not be affected by reboots.
1494 *WARNING* If your board configuration uses automatic
1495 detection of the RAM size, you must make sure that
1496 this memory test is non-destructive. So far, the
1497 following board configurations are known to be
1500 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1501 HERMES, IP860, RPXlite, LWMON, LANTEC,
1502 PCU_E, FLAGADM, TQM8260
1507 Define this variable to stop the system in case of a
1508 fatal error, so that you have to reset it manually.
1509 This is probably NOT a good idea for an embedded
1510 system where you want to system to reboot
1511 automatically as fast as possible, but it may be
1512 useful during development since you can try to debug
1513 the conditions that lead to the situation.
1515 CONFIG_NET_RETRY_COUNT
1517 This variable defines the number of retries for
1518 network operations like ARP, RARP, TFTP, or BOOTP
1519 before giving up the operation. If not defined, a
1520 default value of 5 is used.
1522 - Command Interpreter:
1523 CONFIG_AUTO_COMPLETE
1525 Enable auto completion of commands using TAB.
1527 Note that this feature has NOT been implemented yet
1528 for the "hush" shell.
1533 Define this variable to enable the "hush" shell (from
1534 Busybox) as command line interpreter, thus enabling
1535 powerful command line syntax like
1536 if...then...else...fi conditionals or `&&' and '||'
1537 constructs ("shell scripts").
1539 If undefined, you get the old, much simpler behaviour
1540 with a somewhat smaller memory footprint.
1545 This defines the secondary prompt string, which is
1546 printed when the command interpreter needs more input
1547 to complete a command. Usually "> ".
1551 In the current implementation, the local variables
1552 space and global environment variables space are
1553 separated. Local variables are those you define by
1554 simply typing `name=value'. To access a local
1555 variable later on, you have write `$name' or
1556 `${name}'; to execute the contents of a variable
1557 directly type `$name' at the command prompt.
1559 Global environment variables are those you use
1560 setenv/printenv to work with. To run a command stored
1561 in such a variable, you need to use the run command,
1562 and you must not use the '$' sign to access them.
1564 To store commands and special characters in a
1565 variable, please use double quotation marks
1566 surrounding the whole text of the variable, instead
1567 of the backslashes before semicolons and special
1570 - Commandline Editing and History:
1571 CONFIG_CMDLINE_EDITING
1573 Enable editiong and History functions for interactive
1574 commandline input operations
1576 - Default Environment:
1577 CONFIG_EXTRA_ENV_SETTINGS
1579 Define this to contain any number of null terminated
1580 strings (variable = value pairs) that will be part of
1581 the default environment compiled into the boot image.
1583 For example, place something like this in your
1584 board's config file:
1586 #define CONFIG_EXTRA_ENV_SETTINGS \
1590 Warning: This method is based on knowledge about the
1591 internal format how the environment is stored by the
1592 U-Boot code. This is NOT an official, exported
1593 interface! Although it is unlikely that this format
1594 will change soon, there is no guarantee either.
1595 You better know what you are doing here.
1597 Note: overly (ab)use of the default environment is
1598 discouraged. Make sure to check other ways to preset
1599 the environment like the autoscript function or the
1602 - DataFlash Support:
1603 CONFIG_HAS_DATAFLASH
1605 Defining this option enables DataFlash features and
1606 allows to read/write in Dataflash via the standard
1609 - SystemACE Support:
1612 Adding this option adds support for Xilinx SystemACE
1613 chips attached via some sort of local bus. The address
1614 of the chip must alsh be defined in the
1615 CFG_SYSTEMACE_BASE macro. For example:
1617 #define CONFIG_SYSTEMACE
1618 #define CFG_SYSTEMACE_BASE 0xf0000000
1620 When SystemACE support is added, the "ace" device type
1621 becomes available to the fat commands, i.e. fatls.
1623 - TFTP Fixed UDP Port:
1626 If this is defined, the environment variable tftpsrcp
1627 is used to supply the TFTP UDP source port value.
1628 If tftpsrcp isn't defined, the normal pseudo-random port
1629 number generator is used.
1631 Also, the environment variable tftpdstp is used to supply
1632 the TFTP UDP destination port value. If tftpdstp isn't
1633 defined, the normal port 69 is used.
1635 The purpose for tftpsrcp is to allow a TFTP server to
1636 blindly start the TFTP transfer using the pre-configured
1637 target IP address and UDP port. This has the effect of
1638 "punching through" the (Windows XP) firewall, allowing
1639 the remainder of the TFTP transfer to proceed normally.
1640 A better solution is to properly configure the firewall,
1641 but sometimes that is not allowed.
1643 - Show boot progress:
1644 CONFIG_SHOW_BOOT_PROGRESS
1646 Defining this option allows to add some board-
1647 specific code (calling a user-provided function
1648 "show_boot_progress(int)") that enables you to show
1649 the system's boot progress on some display (for
1650 example, some LED's) on your board. At the moment,
1651 the following checkpoints are implemented:
1654 1 common/cmd_bootm.c before attempting to boot an image
1655 -1 common/cmd_bootm.c Image header has bad magic number
1656 2 common/cmd_bootm.c Image header has correct magic number
1657 -2 common/cmd_bootm.c Image header has bad checksum
1658 3 common/cmd_bootm.c Image header has correct checksum
1659 -3 common/cmd_bootm.c Image data has bad checksum
1660 4 common/cmd_bootm.c Image data has correct checksum
1661 -4 common/cmd_bootm.c Image is for unsupported architecture
1662 5 common/cmd_bootm.c Architecture check OK
1663 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1664 6 common/cmd_bootm.c Image Type check OK
1665 -6 common/cmd_bootm.c gunzip uncompression error
1666 -7 common/cmd_bootm.c Unimplemented compression type
1667 7 common/cmd_bootm.c Uncompression OK
1668 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1669 8 common/cmd_bootm.c Image Type check OK
1670 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1671 9 common/cmd_bootm.c Start initial ramdisk verification
1672 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1673 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1674 10 common/cmd_bootm.c Ramdisk header is OK
1675 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1676 11 common/cmd_bootm.c Ramdisk data has correct checksum
1677 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1678 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1679 13 common/cmd_bootm.c Start multifile image verification
1680 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1681 15 common/cmd_bootm.c All preparation done, transferring control to OS
1683 -30 lib_ppc/board.c Fatal error, hang the system
1684 -31 post/post.c POST test failed, detected by post_output_backlog()
1685 -32 post/post.c POST test failed, detected by post_run_single()
1687 34 common/cmd_doc.c before loading a Image from a DOC device
1688 -35 common/cmd_doc.c Bad usage of "doc" command
1689 35 common/cmd_doc.c correct usage of "doc" command
1690 -36 common/cmd_doc.c No boot device
1691 36 common/cmd_doc.c correct boot device
1692 -37 common/cmd_doc.c Unknown Chip ID on boot device
1693 37 common/cmd_doc.c correct chip ID found, device available
1694 -38 common/cmd_doc.c Read Error on boot device
1695 38 common/cmd_doc.c reading Image header from DOC device OK
1696 -39 common/cmd_doc.c Image header has bad magic number
1697 39 common/cmd_doc.c Image header has correct magic number
1698 -40 common/cmd_doc.c Error reading Image from DOC device
1699 40 common/cmd_doc.c Image header has correct magic number
1700 41 common/cmd_ide.c before loading a Image from a IDE device
1701 -42 common/cmd_ide.c Bad usage of "ide" command
1702 42 common/cmd_ide.c correct usage of "ide" command
1703 -43 common/cmd_ide.c No boot device
1704 43 common/cmd_ide.c boot device found
1705 -44 common/cmd_ide.c Device not available
1706 44 common/cmd_ide.c Device available
1707 -45 common/cmd_ide.c wrong partition selected
1708 45 common/cmd_ide.c partition selected
1709 -46 common/cmd_ide.c Unknown partition table
1710 46 common/cmd_ide.c valid partition table found
1711 -47 common/cmd_ide.c Invalid partition type
1712 47 common/cmd_ide.c correct partition type
1713 -48 common/cmd_ide.c Error reading Image Header on boot device
1714 48 common/cmd_ide.c reading Image Header from IDE device OK
1715 -49 common/cmd_ide.c Image header has bad magic number
1716 49 common/cmd_ide.c Image header has correct magic number
1717 -50 common/cmd_ide.c Image header has bad checksum
1718 50 common/cmd_ide.c Image header has correct checksum
1719 -51 common/cmd_ide.c Error reading Image from IDE device
1720 51 common/cmd_ide.c reading Image from IDE device OK
1721 52 common/cmd_nand.c before loading a Image from a NAND device
1722 -53 common/cmd_nand.c Bad usage of "nand" command
1723 53 common/cmd_nand.c correct usage of "nand" command
1724 -54 common/cmd_nand.c No boot device
1725 54 common/cmd_nand.c boot device found
1726 -55 common/cmd_nand.c Unknown Chip ID on boot device
1727 55 common/cmd_nand.c correct chip ID found, device available
1728 -56 common/cmd_nand.c Error reading Image Header on boot device
1729 56 common/cmd_nand.c reading Image Header from NAND device OK
1730 -57 common/cmd_nand.c Image header has bad magic number
1731 57 common/cmd_nand.c Image header has correct magic number
1732 -58 common/cmd_nand.c Error reading Image from NAND device
1733 58 common/cmd_nand.c reading Image from NAND device OK
1735 -60 common/env_common.c Environment has a bad CRC, using default
1737 64 net/eth.c starting with Ethernetconfiguration.
1738 -64 net/eth.c no Ethernet found.
1739 65 net/eth.c Ethernet found.
1741 -80 common/cmd_net.c usage wrong
1742 80 common/cmd_net.c before calling NetLoop()
1743 -81 common/cmd_net.c some error in NetLoop() occured
1744 81 common/cmd_net.c NetLoop() back without error
1745 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1746 82 common/cmd_net.c trying automatic boot
1747 83 common/cmd_net.c running autoscript
1748 -83 common/cmd_net.c some error in automatic boot or autoscript
1749 84 common/cmd_net.c end without errors
1754 [so far only for SMDK2400 and TRAB boards]
1756 - Modem support endable:
1757 CONFIG_MODEM_SUPPORT
1759 - RTS/CTS Flow control enable:
1762 - Modem debug support:
1763 CONFIG_MODEM_SUPPORT_DEBUG
1765 Enables debugging stuff (char screen[1024], dbg())
1766 for modem support. Useful only with BDI2000.
1768 - Interrupt support (PPC):
1770 There are common interrupt_init() and timer_interrupt()
1771 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1772 for cpu specific initialization. interrupt_init_cpu()
1773 should set decrementer_count to appropriate value. If
1774 cpu resets decrementer automatically after interrupt
1775 (ppc4xx) it should set decrementer_count to zero.
1776 timer_interrupt() calls timer_interrupt_cpu() for cpu
1777 specific handling. If board has watchdog / status_led
1778 / other_activity_monitor it works automatically from
1779 general timer_interrupt().
1783 In the target system modem support is enabled when a
1784 specific key (key combination) is pressed during
1785 power-on. Otherwise U-Boot will boot normally
1786 (autoboot). The key_pressed() fuction is called from
1787 board_init(). Currently key_pressed() is a dummy
1788 function, returning 1 and thus enabling modem
1791 If there are no modem init strings in the
1792 environment, U-Boot proceed to autoboot; the
1793 previous output (banner, info printfs) will be
1796 See also: doc/README.Modem
1799 Configuration Settings:
1800 -----------------------
1802 - CFG_LONGHELP: Defined when you want long help messages included;
1803 undefine this when you're short of memory.
1805 - CFG_PROMPT: This is what U-Boot prints on the console to
1806 prompt for user input.
1808 - CFG_CBSIZE: Buffer size for input from the Console
1810 - CFG_PBSIZE: Buffer size for Console output
1812 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1814 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1815 the application (usually a Linux kernel) when it is
1818 - CFG_BAUDRATE_TABLE:
1819 List of legal baudrate settings for this board.
1821 - CFG_CONSOLE_INFO_QUIET
1822 Suppress display of console information at boot.
1824 - CFG_CONSOLE_IS_IN_ENV
1825 If the board specific function
1826 extern int overwrite_console (void);
1827 returns 1, the stdin, stderr and stdout are switched to the
1828 serial port, else the settings in the environment are used.
1830 - CFG_CONSOLE_OVERWRITE_ROUTINE
1831 Enable the call to overwrite_console().
1833 - CFG_CONSOLE_ENV_OVERWRITE
1834 Enable overwrite of previous console environment settings.
1836 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1837 Begin and End addresses of the area used by the
1841 Enable an alternate, more extensive memory test.
1843 - CFG_MEMTEST_SCRATCH:
1844 Scratch address used by the alternate memory test
1845 You only need to set this if address zero isn't writeable
1847 - CFG_TFTP_LOADADDR:
1848 Default load address for network file downloads
1850 - CFG_LOADS_BAUD_CHANGE:
1851 Enable temporary baudrate change while serial download
1854 Physical start address of SDRAM. _Must_ be 0 here.
1857 Physical start address of Motherboard I/O (if using a
1861 Physical start address of Flash memory.
1864 Physical start address of boot monitor code (set by
1865 make config files to be same as the text base address
1866 (TEXT_BASE) used when linking) - same as
1867 CFG_FLASH_BASE when booting from flash.
1870 Size of memory reserved for monitor code, used to
1871 determine _at_compile_time_ (!) if the environment is
1872 embedded within the U-Boot image, or in a separate
1876 Size of DRAM reserved for malloc() use.
1879 Normally compressed uImages are limited to an
1880 uncompressed size of 8 MBytes. If this is not enough,
1881 you can define CFG_BOOTM_LEN in your board config file
1882 to adjust this setting to your needs.
1885 Maximum size of memory mapped by the startup code of
1886 the Linux kernel; all data that must be processed by
1887 the Linux kernel (bd_info, boot arguments, eventually
1888 initrd image) must be put below this limit.
1890 - CFG_MAX_FLASH_BANKS:
1891 Max number of Flash memory banks
1893 - CFG_MAX_FLASH_SECT:
1894 Max number of sectors on a Flash chip
1896 - CFG_FLASH_ERASE_TOUT:
1897 Timeout for Flash erase operations (in ms)
1899 - CFG_FLASH_WRITE_TOUT:
1900 Timeout for Flash write operations (in ms)
1902 - CFG_FLASH_LOCK_TOUT
1903 Timeout for Flash set sector lock bit operation (in ms)
1905 - CFG_FLASH_UNLOCK_TOUT
1906 Timeout for Flash clear lock bits operation (in ms)
1908 - CFG_FLASH_PROTECTION
1909 If defined, hardware flash sectors protection is used
1910 instead of U-Boot software protection.
1912 - CFG_DIRECT_FLASH_TFTP:
1914 Enable TFTP transfers directly to flash memory;
1915 without this option such a download has to be
1916 performed in two steps: (1) download to RAM, and (2)
1917 copy from RAM to flash.
1919 The two-step approach is usually more reliable, since
1920 you can check if the download worked before you erase
1921 the flash, but in some situations (when sytem RAM is
1922 too limited to allow for a tempory copy of the
1923 downloaded image) this option may be very useful.
1926 Define if the flash driver uses extra elements in the
1927 common flash structure for storing flash geometry.
1929 - CFG_FLASH_CFI_DRIVER
1930 This option also enables the building of the cfi_flash driver
1931 in the drivers directory
1933 - CFG_FLASH_QUIET_TEST
1934 If this option is defined, the common CFI flash doesn't
1935 print it's warning upon not recognized FLASH banks. This
1936 is useful, if some of the configured banks are only
1937 optionally available.
1939 - CFG_RX_ETH_BUFFER:
1940 Defines the number of ethernet receive buffers. On some
1941 ethernet controllers it is recommended to set this value
1942 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1943 buffers can be full shortly after enabling the interface
1944 on high ethernet traffic.
1945 Defaults to 4 if not defined.
1947 The following definitions that deal with the placement and management
1948 of environment data (variable area); in general, we support the
1949 following configurations:
1951 - CFG_ENV_IS_IN_FLASH:
1953 Define this if the environment is in flash memory.
1955 a) The environment occupies one whole flash sector, which is
1956 "embedded" in the text segment with the U-Boot code. This
1957 happens usually with "bottom boot sector" or "top boot
1958 sector" type flash chips, which have several smaller
1959 sectors at the start or the end. For instance, such a
1960 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1961 such a case you would place the environment in one of the
1962 4 kB sectors - with U-Boot code before and after it. With
1963 "top boot sector" type flash chips, you would put the
1964 environment in one of the last sectors, leaving a gap
1965 between U-Boot and the environment.
1969 Offset of environment data (variable area) to the
1970 beginning of flash memory; for instance, with bottom boot
1971 type flash chips the second sector can be used: the offset
1972 for this sector is given here.
1974 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1978 This is just another way to specify the start address of
1979 the flash sector containing the environment (instead of
1982 - CFG_ENV_SECT_SIZE:
1984 Size of the sector containing the environment.
1987 b) Sometimes flash chips have few, equal sized, BIG sectors.
1988 In such a case you don't want to spend a whole sector for
1993 If you use this in combination with CFG_ENV_IS_IN_FLASH
1994 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1995 of this flash sector for the environment. This saves
1996 memory for the RAM copy of the environment.
1998 It may also save flash memory if you decide to use this
1999 when your environment is "embedded" within U-Boot code,
2000 since then the remainder of the flash sector could be used
2001 for U-Boot code. It should be pointed out that this is
2002 STRONGLY DISCOURAGED from a robustness point of view:
2003 updating the environment in flash makes it always
2004 necessary to erase the WHOLE sector. If something goes
2005 wrong before the contents has been restored from a copy in
2006 RAM, your target system will be dead.
2008 - CFG_ENV_ADDR_REDUND
2011 These settings describe a second storage area used to hold
2012 a redundand copy of the environment data, so that there is
2013 a valid backup copy in case there is a power failure during
2014 a "saveenv" operation.
2016 BE CAREFUL! Any changes to the flash layout, and some changes to the
2017 source code will make it necessary to adapt <board>/u-boot.lds*
2021 - CFG_ENV_IS_IN_NVRAM:
2023 Define this if you have some non-volatile memory device
2024 (NVRAM, battery buffered SRAM) which you want to use for the
2030 These two #defines are used to determin the memory area you
2031 want to use for environment. It is assumed that this memory
2032 can just be read and written to, without any special
2035 BE CAREFUL! The first access to the environment happens quite early
2036 in U-Boot initalization (when we try to get the setting of for the
2037 console baudrate). You *MUST* have mappend your NVRAM area then, or
2040 Please note that even with NVRAM we still use a copy of the
2041 environment in RAM: we could work on NVRAM directly, but we want to
2042 keep settings there always unmodified except somebody uses "saveenv"
2043 to save the current settings.
2046 - CFG_ENV_IS_IN_EEPROM:
2048 Use this if you have an EEPROM or similar serial access
2049 device and a driver for it.
2054 These two #defines specify the offset and size of the
2055 environment area within the total memory of your EEPROM.
2057 - CFG_I2C_EEPROM_ADDR:
2058 If defined, specified the chip address of the EEPROM device.
2059 The default address is zero.
2061 - CFG_EEPROM_PAGE_WRITE_BITS:
2062 If defined, the number of bits used to address bytes in a
2063 single page in the EEPROM device. A 64 byte page, for example
2064 would require six bits.
2066 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2067 If defined, the number of milliseconds to delay between
2068 page writes. The default is zero milliseconds.
2070 - CFG_I2C_EEPROM_ADDR_LEN:
2071 The length in bytes of the EEPROM memory array address. Note
2072 that this is NOT the chip address length!
2074 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2075 EEPROM chips that implement "address overflow" are ones
2076 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2077 address and the extra bits end up in the "chip address" bit
2078 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2081 Note that we consider the length of the address field to
2082 still be one byte because the extra address bits are hidden
2083 in the chip address.
2086 The size in bytes of the EEPROM device.
2089 - CFG_ENV_IS_IN_DATAFLASH:
2091 Define this if you have a DataFlash memory device which you
2092 want to use for the environment.
2098 These three #defines specify the offset and size of the
2099 environment area within the total memory of your DataFlash placed
2100 at the specified address.
2102 - CFG_ENV_IS_IN_NAND:
2104 Define this if you have a NAND device which you want to use
2105 for the environment.
2110 These two #defines specify the offset and size of the environment
2111 area within the first NAND device.
2113 - CFG_ENV_OFFSET_REDUND
2115 This setting describes a second storage area of CFG_ENV_SIZE
2116 size used to hold a redundant copy of the environment data,
2117 so that there is a valid backup copy in case there is a
2118 power failure during a "saveenv" operation.
2120 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2121 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2122 the NAND devices block size.
2124 - CFG_SPI_INIT_OFFSET
2126 Defines offset to the initial SPI buffer area in DPRAM. The
2127 area is used at an early stage (ROM part) if the environment
2128 is configured to reside in the SPI EEPROM: We need a 520 byte
2129 scratch DPRAM area. It is used between the two initialization
2130 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2131 to be a good choice since it makes it far enough from the
2132 start of the data area as well as from the stack pointer.
2134 Please note that the environment is read-only until the monitor
2135 has been relocated to RAM and a RAM copy of the environment has been
2136 created; also, when using EEPROM you will have to use getenv_r()
2137 until then to read environment variables.
2139 The environment is protected by a CRC32 checksum. Before the monitor
2140 is relocated into RAM, as a result of a bad CRC you will be working
2141 with the compiled-in default environment - *silently*!!! [This is
2142 necessary, because the first environment variable we need is the
2143 "baudrate" setting for the console - if we have a bad CRC, we don't
2144 have any device yet where we could complain.]
2146 Note: once the monitor has been relocated, then it will complain if
2147 the default environment is used; a new CRC is computed as soon as you
2148 use the "saveenv" command to store a valid environment.
2150 - CFG_FAULT_ECHO_LINK_DOWN:
2151 Echo the inverted Ethernet link state to the fault LED.
2153 Note: If this option is active, then CFG_FAULT_MII_ADDR
2154 also needs to be defined.
2156 - CFG_FAULT_MII_ADDR:
2157 MII address of the PHY to check for the Ethernet link state.
2159 - CFG_64BIT_VSPRINTF:
2160 Makes vsprintf (and all *printf functions) support printing
2161 of 64bit values by using the L quantifier
2163 - CFG_64BIT_STRTOUL:
2164 Adds simple_strtoull that returns a 64bit value
2166 Low Level (hardware related) configuration options:
2167 ---------------------------------------------------
2169 - CFG_CACHELINE_SIZE:
2170 Cache Line Size of the CPU.
2173 Default address of the IMMR after system reset.
2175 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2176 and RPXsuper) to be able to adjust the position of
2177 the IMMR register after a reset.
2179 - Floppy Disk Support:
2180 CFG_FDC_DRIVE_NUMBER
2182 the default drive number (default value 0)
2186 defines the spacing between fdc chipset registers
2191 defines the offset of register from address. It
2192 depends on which part of the data bus is connected to
2193 the fdc chipset. (default value 0)
2195 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2196 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2199 if CFG_FDC_HW_INIT is defined, then the function
2200 fdc_hw_init() is called at the beginning of the FDC
2201 setup. fdc_hw_init() must be provided by the board
2202 source code. It is used to make hardware dependant
2205 - CFG_IMMR: Physical address of the Internal Memory.
2206 DO NOT CHANGE unless you know exactly what you're
2207 doing! (11-4) [MPC8xx/82xx systems only]
2209 - CFG_INIT_RAM_ADDR:
2211 Start address of memory area that can be used for
2212 initial data and stack; please note that this must be
2213 writable memory that is working WITHOUT special
2214 initialization, i. e. you CANNOT use normal RAM which
2215 will become available only after programming the
2216 memory controller and running certain initialization
2219 U-Boot uses the following memory types:
2220 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2221 - MPC824X: data cache
2222 - PPC4xx: data cache
2224 - CFG_GBL_DATA_OFFSET:
2226 Offset of the initial data structure in the memory
2227 area defined by CFG_INIT_RAM_ADDR. Usually
2228 CFG_GBL_DATA_OFFSET is chosen such that the initial
2229 data is located at the end of the available space
2230 (sometimes written as (CFG_INIT_RAM_END -
2231 CFG_INIT_DATA_SIZE), and the initial stack is just
2232 below that area (growing from (CFG_INIT_RAM_ADDR +
2233 CFG_GBL_DATA_OFFSET) downward.
2236 On the MPC824X (or other systems that use the data
2237 cache for initial memory) the address chosen for
2238 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2239 point to an otherwise UNUSED address space between
2240 the top of RAM and the start of the PCI space.
2242 - CFG_SIUMCR: SIU Module Configuration (11-6)
2244 - CFG_SYPCR: System Protection Control (11-9)
2246 - CFG_TBSCR: Time Base Status and Control (11-26)
2248 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2250 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2252 - CFG_SCCR: System Clock and reset Control Register (15-27)
2254 - CFG_OR_TIMING_SDRAM:
2258 periodic timer for refresh
2260 - CFG_DER: Debug Event Register (37-47)
2262 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2263 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2264 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2266 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2268 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2269 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2270 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2271 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2273 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2274 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2275 Machine Mode Register and Memory Periodic Timer
2276 Prescaler definitions (SDRAM timing)
2278 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2279 enable I2C microcode relocation patch (MPC8xx);
2280 define relocation offset in DPRAM [DSP2]
2282 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2283 enable SMC microcode relocation patch (MPC8xx);
2284 define relocation offset in DPRAM [SMC1]
2286 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2287 enable SPI microcode relocation patch (MPC8xx);
2288 define relocation offset in DPRAM [SCC4]
2291 Use OSCM clock mode on MBX8xx board. Be careful,
2292 wrong setting might damage your board. Read
2293 doc/README.MBX before setting this variable!
2295 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2296 Offset of the bootmode word in DPRAM used by post
2297 (Power On Self Tests). This definition overrides
2298 #define'd default value in commproc.h resp.
2301 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2302 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2303 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2304 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2305 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2306 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2307 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2308 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2309 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2312 Get DDR timing information from an I2C EEPROM. Common with pluggable
2313 memory modules such as SODIMMs
2315 I2C address of the SPD EEPROM
2318 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2319 Note that the value must resolve to something your driver can deal with.
2321 - CFG_83XX_DDR_USES_CS0
2322 Only for 83xx systems. If specified, then DDR should be configured
2323 using CS0 and CS1 instead of CS2 and CS3.
2325 - CFG_83XX_DDR_USES_CS0
2326 Only for 83xx systems. If specified, then DDR should be configured
2327 using CS0 and CS1 instead of CS2 and CS3.
2329 - CONFIG_ETHER_ON_FEC[12]
2330 Define to enable FEC[12] on a 8xx series processor.
2332 - CONFIG_FEC[12]_PHY
2333 Define to the hardcoded PHY address which corresponds
2334 to the given FEC; i. e.
2335 #define CONFIG_FEC1_PHY 4
2336 means that the PHY with address 4 is connected to FEC1
2338 When set to -1, means to probe for first available.
2340 - CONFIG_FEC[12]_PHY_NORXERR
2341 The PHY does not have a RXERR line (RMII only).
2342 (so program the FEC to ignore it).
2345 Enable RMII mode for all FECs.
2346 Note that this is a global option, we can't
2347 have one FEC in standard MII mode and another in RMII mode.
2349 - CONFIG_CRC32_VERIFY
2350 Add a verify option to the crc32 command.
2353 => crc32 -v <address> <count> <crc32>
2355 Where address/count indicate a memory area
2356 and crc32 is the correct crc32 which the
2360 Add the "loopw" memory command. This only takes effect if
2361 the memory commands are activated globally (CONFIG_CMD_MEM).
2364 Add the "mdc" and "mwc" memory commands. These are cyclic
2369 This command will print 4 bytes (10,11,12,13) each 500 ms.
2371 => mwc.l 100 12345678 10
2372 This command will write 12345678 to address 100 all 10 ms.
2374 This only takes effect if the memory commands are activated
2375 globally (CONFIG_CMD_MEM).
2377 - CONFIG_SKIP_LOWLEVEL_INIT
2378 - CONFIG_SKIP_RELOCATE_UBOOT
2380 [ARM only] If these variables are defined, then
2381 certain low level initializations (like setting up
2382 the memory controller) are omitted and/or U-Boot does
2383 not relocate itself into RAM.
2384 Normally these variables MUST NOT be defined. The
2385 only exception is when U-Boot is loaded (to RAM) by
2386 some other boot loader or by a debugger which
2387 performs these intializations itself.
2390 Building the Software:
2391 ======================
2393 Building U-Boot has been tested in native PPC environments (on a
2394 PowerBook G3 running LinuxPPC 2000) and in cross environments
2395 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2398 If you are not using a native PPC environment, it is assumed that you
2399 have the GNU cross compiling tools available in your path and named
2400 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2401 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2402 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2405 CROSS_COMPILE = ppc_4xx-
2408 U-Boot is intended to be simple to build. After installing the
2409 sources you must configure U-Boot for one specific board type. This
2414 where "NAME_config" is the name of one of the existing
2415 configurations; see the main Makefile for supported names.
2417 Note: for some board special configuration names may exist; check if
2418 additional information is available from the board vendor; for
2419 instance, the TQM823L systems are available without (standard)
2420 or with LCD support. You can select such additional "features"
2421 when chosing the configuration, i. e.
2424 - will configure for a plain TQM823L, i. e. no LCD support
2426 make TQM823L_LCD_config
2427 - will configure for a TQM823L with U-Boot console on LCD
2432 Finally, type "make all", and you should get some working U-Boot
2433 images ready for download to / installation on your system:
2435 - "u-boot.bin" is a raw binary image
2436 - "u-boot" is an image in ELF binary format
2437 - "u-boot.srec" is in Motorola S-Record format
2439 By default the build is performed locally and the objects are saved
2440 in the source directory. One of the two methods can be used to change
2441 this behavior and build U-Boot to some external directory:
2443 1. Add O= to the make command line invocations:
2445 make O=/tmp/build distclean
2446 make O=/tmp/build NAME_config
2447 make O=/tmp/build all
2449 2. Set environment variable BUILD_DIR to point to the desired location:
2451 export BUILD_DIR=/tmp/build
2456 Note that the command line "O=" setting overrides the BUILD_DIR environment
2460 Please be aware that the Makefiles assume you are using GNU make, so
2461 for instance on NetBSD you might need to use "gmake" instead of
2465 If the system board that you have is not listed, then you will need
2466 to port U-Boot to your hardware platform. To do this, follow these
2469 1. Add a new configuration option for your board to the toplevel
2470 "Makefile" and to the "MAKEALL" script, using the existing
2471 entries as examples. Note that here and at many other places
2472 boards and other names are listed in alphabetical sort order. Please
2474 2. Create a new directory to hold your board specific code. Add any
2475 files you need. In your board directory, you will need at least
2476 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2477 3. Create a new configuration file "include/configs/<board>.h" for
2479 3. If you're porting U-Boot to a new CPU, then also create a new
2480 directory to hold your CPU specific code. Add any files you need.
2481 4. Run "make <board>_config" with your new name.
2482 5. Type "make", and you should get a working "u-boot.srec" file
2483 to be installed on your target system.
2484 6. Debug and solve any problems that might arise.
2485 [Of course, this last step is much harder than it sounds.]
2488 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2489 ==============================================================
2491 If you have modified U-Boot sources (for instance added a new board
2492 or support for new devices, a new CPU, etc.) you are expected to
2493 provide feedback to the other developers. The feedback normally takes
2494 the form of a "patch", i. e. a context diff against a certain (latest
2495 official or latest in CVS) version of U-Boot sources.
2497 But before you submit such a patch, please verify that your modifi-
2498 cation did not break existing code. At least make sure that *ALL* of
2499 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2500 just run the "MAKEALL" script, which will configure and build U-Boot
2501 for ALL supported system. Be warned, this will take a while. You can
2502 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2503 environment variable to the script, i. e. to use the cross tools from
2504 MontaVista's Hard Hat Linux you can type
2506 CROSS_COMPILE=ppc_8xx- MAKEALL
2508 or to build on a native PowerPC system you can type
2510 CROSS_COMPILE=' ' MAKEALL
2512 When using the MAKEALL script, the default behaviour is to build U-Boot
2513 in the source directory. This location can be changed by setting the
2514 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2515 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2516 <source dir>/LOG directory. This default location can be changed by
2517 setting the MAKEALL_LOGDIR environment variable. For example:
2519 export BUILD_DIR=/tmp/build
2520 export MAKEALL_LOGDIR=/tmp/log
2521 CROSS_COMPILE=ppc_8xx- MAKEALL
2523 With the above settings build objects are saved in the /tmp/build, log
2524 files are saved in the /tmp/log and the source tree remains clean during
2525 the whole build process.
2528 See also "U-Boot Porting Guide" below.
2531 Monitor Commands - Overview:
2532 ============================
2534 go - start application at address 'addr'
2535 run - run commands in an environment variable
2536 bootm - boot application image from memory
2537 bootp - boot image via network using BootP/TFTP protocol
2538 tftpboot- boot image via network using TFTP protocol
2539 and env variables "ipaddr" and "serverip"
2540 (and eventually "gatewayip")
2541 rarpboot- boot image via network using RARP/TFTP protocol
2542 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2543 loads - load S-Record file over serial line
2544 loadb - load binary file over serial line (kermit mode)
2546 mm - memory modify (auto-incrementing)
2547 nm - memory modify (constant address)
2548 mw - memory write (fill)
2550 cmp - memory compare
2551 crc32 - checksum calculation
2552 imd - i2c memory display
2553 imm - i2c memory modify (auto-incrementing)
2554 inm - i2c memory modify (constant address)
2555 imw - i2c memory write (fill)
2556 icrc32 - i2c checksum calculation
2557 iprobe - probe to discover valid I2C chip addresses
2558 iloop - infinite loop on address range
2559 isdram - print SDRAM configuration information
2560 sspi - SPI utility commands
2561 base - print or set address offset
2562 printenv- print environment variables
2563 setenv - set environment variables
2564 saveenv - save environment variables to persistent storage
2565 protect - enable or disable FLASH write protection
2566 erase - erase FLASH memory
2567 flinfo - print FLASH memory information
2568 bdinfo - print Board Info structure
2569 iminfo - print header information for application image
2570 coninfo - print console devices and informations
2571 ide - IDE sub-system
2572 loop - infinite loop on address range
2573 loopw - infinite write loop on address range
2574 mtest - simple RAM test
2575 icache - enable or disable instruction cache
2576 dcache - enable or disable data cache
2577 reset - Perform RESET of the CPU
2578 echo - echo args to console
2579 version - print monitor version
2580 help - print online help
2581 ? - alias for 'help'
2584 Monitor Commands - Detailed Description:
2585 ========================================
2589 For now: just type "help <command>".
2592 Environment Variables:
2593 ======================
2595 U-Boot supports user configuration using Environment Variables which
2596 can be made persistent by saving to Flash memory.
2598 Environment Variables are set using "setenv", printed using
2599 "printenv", and saved to Flash using "saveenv". Using "setenv"
2600 without a value can be used to delete a variable from the
2601 environment. As long as you don't save the environment you are
2602 working with an in-memory copy. In case the Flash area containing the
2603 environment is erased by accident, a default environment is provided.
2605 Some configuration options can be set using Environment Variables:
2607 baudrate - see CONFIG_BAUDRATE
2609 bootdelay - see CONFIG_BOOTDELAY
2611 bootcmd - see CONFIG_BOOTCOMMAND
2613 bootargs - Boot arguments when booting an RTOS image
2615 bootfile - Name of the image to load with TFTP
2617 autoload - if set to "no" (any string beginning with 'n'),
2618 "bootp" will just load perform a lookup of the
2619 configuration from the BOOTP server, but not try to
2620 load any image using TFTP
2622 autostart - if set to "yes", an image loaded using the "bootp",
2623 "rarpboot", "tftpboot" or "diskboot" commands will
2624 be automatically started (by internally calling
2627 If set to "no", a standalone image passed to the
2628 "bootm" command will be copied to the load address
2629 (and eventually uncompressed), but NOT be started.
2630 This can be used to load and uncompress arbitrary
2633 i2cfast - (PPC405GP|PPC405EP only)
2634 if set to 'y' configures Linux I2C driver for fast
2635 mode (400kHZ). This environment variable is used in
2636 initialization code. So, for changes to be effective
2637 it must be saved and board must be reset.
2639 initrd_high - restrict positioning of initrd images:
2640 If this variable is not set, initrd images will be
2641 copied to the highest possible address in RAM; this
2642 is usually what you want since it allows for
2643 maximum initrd size. If for some reason you want to
2644 make sure that the initrd image is loaded below the
2645 CFG_BOOTMAPSZ limit, you can set this environment
2646 variable to a value of "no" or "off" or "0".
2647 Alternatively, you can set it to a maximum upper
2648 address to use (U-Boot will still check that it
2649 does not overwrite the U-Boot stack and data).
2651 For instance, when you have a system with 16 MB
2652 RAM, and want to reserve 4 MB from use by Linux,
2653 you can do this by adding "mem=12M" to the value of
2654 the "bootargs" variable. However, now you must make
2655 sure that the initrd image is placed in the first
2656 12 MB as well - this can be done with
2658 setenv initrd_high 00c00000
2660 If you set initrd_high to 0xFFFFFFFF, this is an
2661 indication to U-Boot that all addresses are legal
2662 for the Linux kernel, including addresses in flash
2663 memory. In this case U-Boot will NOT COPY the
2664 ramdisk at all. This may be useful to reduce the
2665 boot time on your system, but requires that this
2666 feature is supported by your Linux kernel.
2668 ipaddr - IP address; needed for tftpboot command
2670 loadaddr - Default load address for commands like "bootp",
2671 "rarpboot", "tftpboot", "loadb" or "diskboot"
2673 loads_echo - see CONFIG_LOADS_ECHO
2675 serverip - TFTP server IP address; needed for tftpboot command
2677 bootretry - see CONFIG_BOOT_RETRY_TIME
2679 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2681 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2683 ethprime - When CONFIG_NET_MULTI is enabled controls which
2684 interface is used first.
2686 ethact - When CONFIG_NET_MULTI is enabled controls which
2687 interface is currently active. For example you
2688 can do the following
2690 => setenv ethact FEC ETHERNET
2691 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2692 => setenv ethact SCC ETHERNET
2693 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2695 netretry - When set to "no" each network operation will
2696 either succeed or fail without retrying.
2697 When set to "once" the network operation will
2698 fail when all the available network interfaces
2699 are tried once without success.
2700 Useful on scripts which control the retry operation
2703 tftpsrcport - If this is set, the value is used for TFTP's
2706 tftpdstport - If this is set, the value is used for TFTP's UDP
2707 destination port instead of the Well Know Port 69.
2709 vlan - When set to a value < 4095 the traffic over
2710 ethernet is encapsulated/received over 802.1q
2713 The following environment variables may be used and automatically
2714 updated by the network boot commands ("bootp" and "rarpboot"),
2715 depending the information provided by your boot server:
2717 bootfile - see above
2718 dnsip - IP address of your Domain Name Server
2719 dnsip2 - IP address of your secondary Domain Name Server
2720 gatewayip - IP address of the Gateway (Router) to use
2721 hostname - Target hostname
2723 netmask - Subnet Mask
2724 rootpath - Pathname of the root filesystem on the NFS server
2725 serverip - see above
2728 There are two special Environment Variables:
2730 serial# - contains hardware identification information such
2731 as type string and/or serial number
2732 ethaddr - Ethernet address
2734 These variables can be set only once (usually during manufacturing of
2735 the board). U-Boot refuses to delete or overwrite these variables
2736 once they have been set once.
2739 Further special Environment Variables:
2741 ver - Contains the U-Boot version string as printed
2742 with the "version" command. This variable is
2743 readonly (see CONFIG_VERSION_VARIABLE).
2746 Please note that changes to some configuration parameters may take
2747 only effect after the next boot (yes, that's just like Windoze :-).
2750 Command Line Parsing:
2751 =====================
2753 There are two different command line parsers available with U-Boot:
2754 the old "simple" one, and the much more powerful "hush" shell:
2756 Old, simple command line parser:
2757 --------------------------------
2759 - supports environment variables (through setenv / saveenv commands)
2760 - several commands on one line, separated by ';'
2761 - variable substitution using "... ${name} ..." syntax
2762 - special characters ('$', ';') can be escaped by prefixing with '\',
2764 setenv bootcmd bootm \${address}
2765 - You can also escape text by enclosing in single apostrophes, for example:
2766 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2771 - similar to Bourne shell, with control structures like
2772 if...then...else...fi, for...do...done; while...do...done,
2773 until...do...done, ...
2774 - supports environment ("global") variables (through setenv / saveenv
2775 commands) and local shell variables (through standard shell syntax
2776 "name=value"); only environment variables can be used with "run"
2782 (1) If a command line (or an environment variable executed by a "run"
2783 command) contains several commands separated by semicolon, and
2784 one of these commands fails, then the remaining commands will be
2787 (2) If you execute several variables with one call to run (i. e.
2788 calling run with a list af variables as arguments), any failing
2789 command will cause "run" to terminate, i. e. the remaining
2790 variables are not executed.
2792 Note for Redundant Ethernet Interfaces:
2793 =======================================
2795 Some boards come with redundant ethernet interfaces; U-Boot supports
2796 such configurations and is capable of automatic selection of a
2797 "working" interface when needed. MAC assignment works as follows:
2799 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2800 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2801 "eth1addr" (=>eth1), "eth2addr", ...
2803 If the network interface stores some valid MAC address (for instance
2804 in SROM), this is used as default address if there is NO correspon-
2805 ding setting in the environment; if the corresponding environment
2806 variable is set, this overrides the settings in the card; that means:
2808 o If the SROM has a valid MAC address, and there is no address in the
2809 environment, the SROM's address is used.
2811 o If there is no valid address in the SROM, and a definition in the
2812 environment exists, then the value from the environment variable is
2815 o If both the SROM and the environment contain a MAC address, and
2816 both addresses are the same, this MAC address is used.
2818 o If both the SROM and the environment contain a MAC address, and the
2819 addresses differ, the value from the environment is used and a
2822 o If neither SROM nor the environment contain a MAC address, an error
2829 The "boot" commands of this monitor operate on "image" files which
2830 can be basicly anything, preceeded by a special header; see the
2831 definitions in include/image.h for details; basicly, the header
2832 defines the following image properties:
2834 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2835 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2836 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2837 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2838 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2839 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2840 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2841 * Compression Type (uncompressed, gzip, bzip2)
2847 The header is marked by a special Magic Number, and both the header
2848 and the data portions of the image are secured against corruption by
2855 Although U-Boot should support any OS or standalone application
2856 easily, the main focus has always been on Linux during the design of
2859 U-Boot includes many features that so far have been part of some
2860 special "boot loader" code within the Linux kernel. Also, any
2861 "initrd" images to be used are no longer part of one big Linux image;
2862 instead, kernel and "initrd" are separate images. This implementation
2863 serves several purposes:
2865 - the same features can be used for other OS or standalone
2866 applications (for instance: using compressed images to reduce the
2867 Flash memory footprint)
2869 - it becomes much easier to port new Linux kernel versions because
2870 lots of low-level, hardware dependent stuff are done by U-Boot
2872 - the same Linux kernel image can now be used with different "initrd"
2873 images; of course this also means that different kernel images can
2874 be run with the same "initrd". This makes testing easier (you don't
2875 have to build a new "zImage.initrd" Linux image when you just
2876 change a file in your "initrd"). Also, a field-upgrade of the
2877 software is easier now.
2883 Porting Linux to U-Boot based systems:
2884 ---------------------------------------
2886 U-Boot cannot save you from doing all the necessary modifications to
2887 configure the Linux device drivers for use with your target hardware
2888 (no, we don't intend to provide a full virtual machine interface to
2891 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2893 Just make sure your machine specific header file (for instance
2894 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2895 Information structure as we define in include/u-boot.h, and make
2896 sure that your definition of IMAP_ADDR uses the same value as your
2897 U-Boot configuration in CFG_IMMR.
2900 Configuring the Linux kernel:
2901 -----------------------------
2903 No specific requirements for U-Boot. Make sure you have some root
2904 device (initial ramdisk, NFS) for your target system.
2907 Building a Linux Image:
2908 -----------------------
2910 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2911 not used. If you use recent kernel source, a new build target
2912 "uImage" will exist which automatically builds an image usable by
2913 U-Boot. Most older kernels also have support for a "pImage" target,
2914 which was introduced for our predecessor project PPCBoot and uses a
2915 100% compatible format.
2924 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2925 encapsulate a compressed Linux kernel image with header information,
2926 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2928 * build a standard "vmlinux" kernel image (in ELF binary format):
2930 * convert the kernel into a raw binary image:
2932 ${CROSS_COMPILE}-objcopy -O binary \
2933 -R .note -R .comment \
2934 -S vmlinux linux.bin
2936 * compress the binary image:
2940 * package compressed binary image for U-Boot:
2942 mkimage -A ppc -O linux -T kernel -C gzip \
2943 -a 0 -e 0 -n "Linux Kernel Image" \
2944 -d linux.bin.gz uImage
2947 The "mkimage" tool can also be used to create ramdisk images for use
2948 with U-Boot, either separated from the Linux kernel image, or
2949 combined into one file. "mkimage" encapsulates the images with a 64
2950 byte header containing information about target architecture,
2951 operating system, image type, compression method, entry points, time
2952 stamp, CRC32 checksums, etc.
2954 "mkimage" can be called in two ways: to verify existing images and
2955 print the header information, or to build new images.
2957 In the first form (with "-l" option) mkimage lists the information
2958 contained in the header of an existing U-Boot image; this includes
2959 checksum verification:
2961 tools/mkimage -l image
2962 -l ==> list image header information
2964 The second form (with "-d" option) is used to build a U-Boot image
2965 from a "data file" which is used as image payload:
2967 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2968 -n name -d data_file image
2969 -A ==> set architecture to 'arch'
2970 -O ==> set operating system to 'os'
2971 -T ==> set image type to 'type'
2972 -C ==> set compression type 'comp'
2973 -a ==> set load address to 'addr' (hex)
2974 -e ==> set entry point to 'ep' (hex)
2975 -n ==> set image name to 'name'
2976 -d ==> use image data from 'datafile'
2978 Right now, all Linux kernels for PowerPC systems use the same load
2979 address (0x00000000), but the entry point address depends on the
2982 - 2.2.x kernels have the entry point at 0x0000000C,
2983 - 2.3.x and later kernels have the entry point at 0x00000000.
2985 So a typical call to build a U-Boot image would read:
2987 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2988 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2989 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2990 > examples/uImage.TQM850L
2991 Image Name: 2.4.4 kernel for TQM850L
2992 Created: Wed Jul 19 02:34:59 2000
2993 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2994 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2995 Load Address: 0x00000000
2996 Entry Point: 0x00000000
2998 To verify the contents of the image (or check for corruption):
3000 -> tools/mkimage -l examples/uImage.TQM850L
3001 Image Name: 2.4.4 kernel for TQM850L
3002 Created: Wed Jul 19 02:34:59 2000
3003 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3004 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3005 Load Address: 0x00000000
3006 Entry Point: 0x00000000
3008 NOTE: for embedded systems where boot time is critical you can trade
3009 speed for memory and install an UNCOMPRESSED image instead: this
3010 needs more space in Flash, but boots much faster since it does not
3011 need to be uncompressed:
3013 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3014 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3015 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3016 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3017 > examples/uImage.TQM850L-uncompressed
3018 Image Name: 2.4.4 kernel for TQM850L
3019 Created: Wed Jul 19 02:34:59 2000
3020 Image Type: PowerPC Linux Kernel Image (uncompressed)
3021 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3022 Load Address: 0x00000000
3023 Entry Point: 0x00000000
3026 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3027 when your kernel is intended to use an initial ramdisk:
3029 -> tools/mkimage -n 'Simple Ramdisk Image' \
3030 > -A ppc -O linux -T ramdisk -C gzip \
3031 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3032 Image Name: Simple Ramdisk Image
3033 Created: Wed Jan 12 14:01:50 2000
3034 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3035 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3036 Load Address: 0x00000000
3037 Entry Point: 0x00000000
3040 Installing a Linux Image:
3041 -------------------------
3043 To downloading a U-Boot image over the serial (console) interface,
3044 you must convert the image to S-Record format:
3046 objcopy -I binary -O srec examples/image examples/image.srec
3048 The 'objcopy' does not understand the information in the U-Boot
3049 image header, so the resulting S-Record file will be relative to
3050 address 0x00000000. To load it to a given address, you need to
3051 specify the target address as 'offset' parameter with the 'loads'
3054 Example: install the image to address 0x40100000 (which on the
3055 TQM8xxL is in the first Flash bank):
3057 => erase 40100000 401FFFFF
3063 ## Ready for S-Record download ...
3064 ~>examples/image.srec
3065 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3067 15989 15990 15991 15992
3068 [file transfer complete]
3070 ## Start Addr = 0x00000000
3073 You can check the success of the download using the 'iminfo' command;
3074 this includes a checksum verification so you can be sure no data
3075 corruption happened:
3079 ## Checking Image at 40100000 ...
3080 Image Name: 2.2.13 for initrd on TQM850L
3081 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3082 Data Size: 335725 Bytes = 327 kB = 0 MB
3083 Load Address: 00000000
3084 Entry Point: 0000000c
3085 Verifying Checksum ... OK
3091 The "bootm" command is used to boot an application that is stored in
3092 memory (RAM or Flash). In case of a Linux kernel image, the contents
3093 of the "bootargs" environment variable is passed to the kernel as
3094 parameters. You can check and modify this variable using the
3095 "printenv" and "setenv" commands:
3098 => printenv bootargs
3099 bootargs=root=/dev/ram
3101 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3103 => printenv bootargs
3104 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3107 ## Booting Linux kernel at 40020000 ...
3108 Image Name: 2.2.13 for NFS on TQM850L
3109 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3110 Data Size: 381681 Bytes = 372 kB = 0 MB
3111 Load Address: 00000000
3112 Entry Point: 0000000c
3113 Verifying Checksum ... OK
3114 Uncompressing Kernel Image ... OK
3115 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
3116 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3117 time_init: decrementer frequency = 187500000/60
3118 Calibrating delay loop... 49.77 BogoMIPS
3119 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3122 If you want to boot a Linux kernel with initial ram disk, you pass
3123 the memory addresses of both the kernel and the initrd image (PPBCOOT
3124 format!) to the "bootm" command:
3126 => imi 40100000 40200000
3128 ## Checking Image at 40100000 ...
3129 Image Name: 2.2.13 for initrd on TQM850L
3130 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3131 Data Size: 335725 Bytes = 327 kB = 0 MB
3132 Load Address: 00000000
3133 Entry Point: 0000000c
3134 Verifying Checksum ... OK
3136 ## Checking Image at 40200000 ...
3137 Image Name: Simple Ramdisk Image
3138 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3139 Data Size: 566530 Bytes = 553 kB = 0 MB
3140 Load Address: 00000000
3141 Entry Point: 00000000
3142 Verifying Checksum ... OK
3144 => bootm 40100000 40200000
3145 ## Booting Linux kernel at 40100000 ...
3146 Image Name: 2.2.13 for initrd on TQM850L
3147 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3148 Data Size: 335725 Bytes = 327 kB = 0 MB
3149 Load Address: 00000000
3150 Entry Point: 0000000c
3151 Verifying Checksum ... OK
3152 Uncompressing Kernel Image ... OK
3153 ## Loading RAMDisk Image at 40200000 ...
3154 Image Name: Simple Ramdisk Image
3155 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3156 Data Size: 566530 Bytes = 553 kB = 0 MB
3157 Load Address: 00000000
3158 Entry Point: 00000000
3159 Verifying Checksum ... OK
3160 Loading Ramdisk ... OK
3161 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
3162 Boot arguments: root=/dev/ram
3163 time_init: decrementer frequency = 187500000/60
3164 Calibrating delay loop... 49.77 BogoMIPS
3166 RAMDISK: Compressed image found at block 0
3167 VFS: Mounted root (ext2 filesystem).
3171 Boot Linux and pass a flat device tree:
3174 First, U-Boot must be compiled with the appropriate defines. See the section
3175 titled "Linux Kernel Interface" above for a more in depth explanation. The
3176 following is an example of how to start a kernel and pass an updated
3182 oft=oftrees/mpc8540ads.dtb
3183 => tftp $oftaddr $oft
3184 Speed: 1000, full duplex
3186 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3187 Filename 'oftrees/mpc8540ads.dtb'.
3188 Load address: 0x300000
3191 Bytes transferred = 4106 (100a hex)
3192 => tftp $loadaddr $bootfile
3193 Speed: 1000, full duplex
3195 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3197 Load address: 0x200000
3198 Loading:############
3200 Bytes transferred = 1029407 (fb51f hex)
3205 => bootm $loadaddr - $oftaddr
3206 ## Booting image at 00200000 ...
3207 Image Name: Linux-2.6.17-dirty
3208 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3209 Data Size: 1029343 Bytes = 1005.2 kB
3210 Load Address: 00000000
3211 Entry Point: 00000000
3212 Verifying Checksum ... OK
3213 Uncompressing Kernel Image ... OK
3214 Booting using flat device tree at 0x300000
3215 Using MPC85xx ADS machine description
3216 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3220 More About U-Boot Image Types:
3221 ------------------------------
3223 U-Boot supports the following image types:
3225 "Standalone Programs" are directly runnable in the environment
3226 provided by U-Boot; it is expected that (if they behave
3227 well) you can continue to work in U-Boot after return from
3228 the Standalone Program.
3229 "OS Kernel Images" are usually images of some Embedded OS which
3230 will take over control completely. Usually these programs
3231 will install their own set of exception handlers, device
3232 drivers, set up the MMU, etc. - this means, that you cannot
3233 expect to re-enter U-Boot except by resetting the CPU.
3234 "RAMDisk Images" are more or less just data blocks, and their
3235 parameters (address, size) are passed to an OS kernel that is
3237 "Multi-File Images" contain several images, typically an OS
3238 (Linux) kernel image and one or more data images like
3239 RAMDisks. This construct is useful for instance when you want
3240 to boot over the network using BOOTP etc., where the boot
3241 server provides just a single image file, but you want to get
3242 for instance an OS kernel and a RAMDisk image.
3244 "Multi-File Images" start with a list of image sizes, each
3245 image size (in bytes) specified by an "uint32_t" in network
3246 byte order. This list is terminated by an "(uint32_t)0".
3247 Immediately after the terminating 0 follow the images, one by
3248 one, all aligned on "uint32_t" boundaries (size rounded up to
3249 a multiple of 4 bytes).
3251 "Firmware Images" are binary images containing firmware (like
3252 U-Boot or FPGA images) which usually will be programmed to
3255 "Script files" are command sequences that will be executed by
3256 U-Boot's command interpreter; this feature is especially
3257 useful when you configure U-Boot to use a real shell (hush)
3258 as command interpreter.
3264 One of the features of U-Boot is that you can dynamically load and
3265 run "standalone" applications, which can use some resources of
3266 U-Boot like console I/O functions or interrupt services.
3268 Two simple examples are included with the sources:
3273 'examples/hello_world.c' contains a small "Hello World" Demo
3274 application; it is automatically compiled when you build U-Boot.
3275 It's configured to run at address 0x00040004, so you can play with it
3279 ## Ready for S-Record download ...
3280 ~>examples/hello_world.srec
3281 1 2 3 4 5 6 7 8 9 10 11 ...
3282 [file transfer complete]
3284 ## Start Addr = 0x00040004
3286 => go 40004 Hello World! This is a test.
3287 ## Starting application at 0x00040004 ...
3298 Hit any key to exit ...
3300 ## Application terminated, rc = 0x0
3302 Another example, which demonstrates how to register a CPM interrupt
3303 handler with the U-Boot code, can be found in 'examples/timer.c'.
3304 Here, a CPM timer is set up to generate an interrupt every second.
3305 The interrupt service routine is trivial, just printing a '.'
3306 character, but this is just a demo program. The application can be
3307 controlled by the following keys:
3309 ? - print current values og the CPM Timer registers
3310 b - enable interrupts and start timer
3311 e - stop timer and disable interrupts
3312 q - quit application
3315 ## Ready for S-Record download ...
3316 ~>examples/timer.srec
3317 1 2 3 4 5 6 7 8 9 10 11 ...
3318 [file transfer complete]
3320 ## Start Addr = 0x00040004
3323 ## Starting application at 0x00040004 ...
3326 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3329 [q, b, e, ?] Set interval 1000000 us
3332 [q, b, e, ?] ........
3333 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3336 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3339 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3342 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3344 [q, b, e, ?] ...Stopping timer
3346 [q, b, e, ?] ## Application terminated, rc = 0x0
3352 Over time, many people have reported problems when trying to use the
3353 "minicom" terminal emulation program for serial download. I (wd)
3354 consider minicom to be broken, and recommend not to use it. Under
3355 Unix, I recommend to use C-Kermit for general purpose use (and
3356 especially for kermit binary protocol download ("loadb" command), and
3357 use "cu" for S-Record download ("loads" command).
3359 Nevertheless, if you absolutely want to use it try adding this
3360 configuration to your "File transfer protocols" section:
3362 Name Program Name U/D FullScr IO-Red. Multi
3363 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3364 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3370 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3371 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3373 Building requires a cross environment; it is known to work on
3374 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3375 need gmake since the Makefiles are not compatible with BSD make).
3376 Note that the cross-powerpc package does not install include files;
3377 attempting to build U-Boot will fail because <machine/ansi.h> is
3378 missing. This file has to be installed and patched manually:
3380 # cd /usr/pkg/cross/powerpc-netbsd/include
3382 # ln -s powerpc machine
3383 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3384 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3386 Native builds *don't* work due to incompatibilities between native
3387 and U-Boot include files.
3389 Booting assumes that (the first part of) the image booted is a
3390 stage-2 loader which in turn loads and then invokes the kernel
3391 proper. Loader sources will eventually appear in the NetBSD source
3392 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3393 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3396 Implementation Internals:
3397 =========================
3399 The following is not intended to be a complete description of every
3400 implementation detail. However, it should help to understand the
3401 inner workings of U-Boot and make it easier to port it to custom
3405 Initial Stack, Global Data:
3406 ---------------------------
3408 The implementation of U-Boot is complicated by the fact that U-Boot
3409 starts running out of ROM (flash memory), usually without access to
3410 system RAM (because the memory controller is not initialized yet).
3411 This means that we don't have writable Data or BSS segments, and BSS
3412 is not initialized as zero. To be able to get a C environment working
3413 at all, we have to allocate at least a minimal stack. Implementation
3414 options for this are defined and restricted by the CPU used: Some CPU
3415 models provide on-chip memory (like the IMMR area on MPC8xx and
3416 MPC826x processors), on others (parts of) the data cache can be
3417 locked as (mis-) used as memory, etc.
3419 Chris Hallinan posted a good summary of these issues to the
3420 u-boot-users mailing list:
3422 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3423 From: "Chris Hallinan" <clh@net1plus.com>
3424 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3427 Correct me if I'm wrong, folks, but the way I understand it
3428 is this: Using DCACHE as initial RAM for Stack, etc, does not
3429 require any physical RAM backing up the cache. The cleverness
3430 is that the cache is being used as a temporary supply of
3431 necessary storage before the SDRAM controller is setup. It's
3432 beyond the scope of this list to expain the details, but you
3433 can see how this works by studying the cache architecture and
3434 operation in the architecture and processor-specific manuals.
3436 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3437 is another option for the system designer to use as an
3438 initial stack/ram area prior to SDRAM being available. Either
3439 option should work for you. Using CS 4 should be fine if your
3440 board designers haven't used it for something that would
3441 cause you grief during the initial boot! It is frequently not
3444 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3445 with your processor/board/system design. The default value
3446 you will find in any recent u-boot distribution in
3447 walnut.h should work for you. I'd set it to a value larger
3448 than your SDRAM module. If you have a 64MB SDRAM module, set
3449 it above 400_0000. Just make sure your board has no resources
3450 that are supposed to respond to that address! That code in
3451 start.S has been around a while and should work as is when
3452 you get the config right.
3457 It is essential to remember this, since it has some impact on the C
3458 code for the initialization procedures:
3460 * Initialized global data (data segment) is read-only. Do not attempt
3463 * Do not use any unitialized global data (or implicitely initialized
3464 as zero data - BSS segment) at all - this is undefined, initiali-
3465 zation is performed later (when relocating to RAM).
3467 * Stack space is very limited. Avoid big data buffers or things like
3470 Having only the stack as writable memory limits means we cannot use
3471 normal global data to share information beween the code. But it
3472 turned out that the implementation of U-Boot can be greatly
3473 simplified by making a global data structure (gd_t) available to all
3474 functions. We could pass a pointer to this data as argument to _all_
3475 functions, but this would bloat the code. Instead we use a feature of
3476 the GCC compiler (Global Register Variables) to share the data: we
3477 place a pointer (gd) to the global data into a register which we
3478 reserve for this purpose.
3480 When choosing a register for such a purpose we are restricted by the
3481 relevant (E)ABI specifications for the current architecture, and by
3482 GCC's implementation.
3484 For PowerPC, the following registers have specific use:
3487 R3-R4: parameter passing and return values
3488 R5-R10: parameter passing
3489 R13: small data area pointer
3493 (U-Boot also uses R14 as internal GOT pointer.)
3495 ==> U-Boot will use R29 to hold a pointer to the global data
3497 Note: on PPC, we could use a static initializer (since the
3498 address of the global data structure is known at compile time),
3499 but it turned out that reserving a register results in somewhat
3500 smaller code - although the code savings are not that big (on
3501 average for all boards 752 bytes for the whole U-Boot image,
3502 624 text + 127 data).
3504 On ARM, the following registers are used:
3506 R0: function argument word/integer result
3507 R1-R3: function argument word
3509 R10: stack limit (used only if stack checking if enabled)
3510 R11: argument (frame) pointer
3511 R12: temporary workspace
3514 R15: program counter
3516 ==> U-Boot will use R8 to hold a pointer to the global data
3518 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3519 or current versions of GCC may "optimize" the code too much.
3524 U-Boot runs in system state and uses physical addresses, i.e. the
3525 MMU is not used either for address mapping nor for memory protection.
3527 The available memory is mapped to fixed addresses using the memory
3528 controller. In this process, a contiguous block is formed for each
3529 memory type (Flash, SDRAM, SRAM), even when it consists of several
3530 physical memory banks.
3532 U-Boot is installed in the first 128 kB of the first Flash bank (on
3533 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3534 booting and sizing and initializing DRAM, the code relocates itself
3535 to the upper end of DRAM. Immediately below the U-Boot code some
3536 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3537 configuration setting]. Below that, a structure with global Board
3538 Info data is placed, followed by the stack (growing downward).
3540 Additionally, some exception handler code is copied to the low 8 kB
3541 of DRAM (0x00000000 ... 0x00001FFF).
3543 So a typical memory configuration with 16 MB of DRAM could look like
3546 0x0000 0000 Exception Vector code
3549 0x0000 2000 Free for Application Use
3555 0x00FB FF20 Monitor Stack (Growing downward)
3556 0x00FB FFAC Board Info Data and permanent copy of global data
3557 0x00FC 0000 Malloc Arena
3560 0x00FE 0000 RAM Copy of Monitor Code
3561 ... eventually: LCD or video framebuffer
3562 ... eventually: pRAM (Protected RAM - unchanged by reset)
3563 0x00FF FFFF [End of RAM]
3566 System Initialization:
3567 ----------------------
3569 In the reset configuration, U-Boot starts at the reset entry point
3570 (on most PowerPC systens at address 0x00000100). Because of the reset
3571 configuration for CS0# this is a mirror of the onboard Flash memory.
3572 To be able to re-map memory U-Boot then jumps to its link address.
3573 To be able to implement the initialization code in C, a (small!)
3574 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3575 which provide such a feature like MPC8xx or MPC8260), or in a locked
3576 part of the data cache. After that, U-Boot initializes the CPU core,
3577 the caches and the SIU.
3579 Next, all (potentially) available memory banks are mapped using a
3580 preliminary mapping. For example, we put them on 512 MB boundaries
3581 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3582 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3583 programmed for SDRAM access. Using the temporary configuration, a
3584 simple memory test is run that determines the size of the SDRAM
3587 When there is more than one SDRAM bank, and the banks are of
3588 different size, the largest is mapped first. For equal size, the first
3589 bank (CS2#) is mapped first. The first mapping is always for address
3590 0x00000000, with any additional banks following immediately to create
3591 contiguous memory starting from 0.
3593 Then, the monitor installs itself at the upper end of the SDRAM area
3594 and allocates memory for use by malloc() and for the global Board
3595 Info data; also, the exception vector code is copied to the low RAM
3596 pages, and the final stack is set up.
3598 Only after this relocation will you have a "normal" C environment;
3599 until that you are restricted in several ways, mostly because you are
3600 running from ROM, and because the code will have to be relocated to a
3604 U-Boot Porting Guide:
3605 ----------------------
3607 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3611 int main (int argc, char *argv[])
3613 sighandler_t no_more_time;
3615 signal (SIGALRM, no_more_time);
3616 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3618 if (available_money > available_manpower) {
3619 pay consultant to port U-Boot;
3623 Download latest U-Boot source;
3625 Subscribe to u-boot-users mailing list;
3628 email ("Hi, I am new to U-Boot, how do I get started?");
3632 Read the README file in the top level directory;
3633 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3634 Read the source, Luke;
3637 if (available_money > toLocalCurrency ($2500)) {
3640 Add a lot of aggravation and time;
3643 Create your own board support subdirectory;
3645 Create your own board config file;
3649 Add / modify source code;
3653 email ("Hi, I am having problems...");
3655 Send patch file to Wolfgang;
3660 void no_more_time (int sig)
3669 All contributions to U-Boot should conform to the Linux kernel
3670 coding style; see the file "Documentation/CodingStyle" and the script
3671 "scripts/Lindent" in your Linux kernel source directory. In sources
3672 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3673 spaces before parameters to function calls) is actually used.
3675 Source files originating from a different project (for example the
3676 MTD subsystem) are generally exempt from these guidelines and are not
3677 reformated to ease subsequent migration to newer versions of those
3680 Please note that U-Boot is implemented in C (and to some small parts in
3681 Assembler); no C++ is used, so please do not use C++ style comments (//)
3684 Please also stick to the following formatting rules:
3685 - remove any trailing white space
3686 - use TAB characters for indentation, not spaces
3687 - make sure NOT to use DOS '\r\n' line feeds
3688 - do not add more than 2 empty lines to source files
3689 - do not add trailing empty lines to source files
3691 Submissions which do not conform to the standards may be returned
3692 with a request to reformat the changes.
3698 Since the number of patches for U-Boot is growing, we need to
3699 establish some rules. Submissions which do not conform to these rules
3700 may be rejected, even when they contain important and valuable stuff.
3702 Patches shall be sent to the u-boot-users mailing list.
3704 When you send a patch, please include the following information with
3707 * For bug fixes: a description of the bug and how your patch fixes
3708 this bug. Please try to include a way of demonstrating that the
3709 patch actually fixes something.
3711 * For new features: a description of the feature and your
3714 * A CHANGELOG entry as plaintext (separate from the patch)
3716 * For major contributions, your entry to the CREDITS file
3718 * When you add support for a new board, don't forget to add this
3719 board to the MAKEALL script, too.
3721 * If your patch adds new configuration options, don't forget to
3722 document these in the README file.
3724 * The patch itself. If you are accessing the CVS repository use "cvs
3725 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3726 version of diff does not support these options, then get the latest
3727 version of GNU diff.
3729 The current directory when running this command shall be the top
3730 level directory of the U-Boot source tree, or it's parent directory
3731 (i. e. please make sure that your patch includes sufficient
3732 directory information for the affected files).
3734 We accept patches as plain text, MIME attachments or as uuencoded
3737 * If one logical set of modifications affects or creates several
3738 files, all these changes shall be submitted in a SINGLE patch file.
3740 * Changesets that contain different, unrelated modifications shall be
3741 submitted as SEPARATE patches, one patch per changeset.
3746 * Before sending the patch, run the MAKEALL script on your patched
3747 source tree and make sure that no errors or warnings are reported
3748 for any of the boards.
3750 * Keep your modifications to the necessary minimum: A patch
3751 containing several unrelated changes or arbitrary reformats will be
3752 returned with a request to re-formatting / split it.
3754 * If you modify existing code, make sure that your new code does not
3755 add to the memory footprint of the code ;-) Small is beautiful!
3756 When adding new features, these should compile conditionally only
3757 (using #ifdef), and the resulting code with the new feature
3758 disabled must not need more memory than the old code without your
3761 * Remember that there is a size limit of 40 kB per message on the
3762 u-boot-users mailing list. Compression may help.
projects / karo-tx-uboot.git / blob