2 # (C) Copyright 2000 - 2008
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - blackfin Files specific to Analog Devices Blackfin CPUs
155 - i386 Files specific to i386 CPUs
156 - ixp Files specific to Intel XScale IXP CPUs
157 - leon2 Files specific to Gaisler LEON2 SPARC CPU
158 - leon3 Files specific to Gaisler LEON3 SPARC CPU
159 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 - mips Files specific to MIPS CPUs
165 - mpc5xx Files specific to Freescale MPC5xx CPUs
166 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
167 - mpc8xx Files specific to Freescale MPC8xx CPUs
168 - mpc8220 Files specific to Freescale MPC8220 CPUs
169 - mpc824x Files specific to Freescale MPC824x CPUs
170 - mpc8260 Files specific to Freescale MPC8260 CPUs
171 - mpc85xx Files specific to Freescale MPC85xx CPUs
172 - nios Files specific to Altera NIOS CPUs
173 - nios2 Files specific to Altera Nios-II CPUs
174 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
175 - pxa Files specific to Intel XScale PXA CPUs
176 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
177 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
178 - disk Code for disk drive partition handling
179 - doc Documentation (don't expect too much)
180 - drivers Commonly used device drivers
181 - dtt Digital Thermometer and Thermostat drivers
182 - examples Example code for standalone applications, etc.
183 - include Header Files
184 - lib_arm Files generic to ARM architecture
185 - lib_avr32 Files generic to AVR32 architecture
186 - lib_blackfin Files generic to Blackfin architecture
187 - lib_generic Files generic to all architectures
188 - lib_i386 Files generic to i386 architecture
189 - lib_m68k Files generic to m68k architecture
190 - lib_mips Files generic to MIPS architecture
191 - lib_nios Files generic to NIOS architecture
192 - lib_ppc Files generic to PowerPC architecture
193 - lib_sparc Files generic to SPARC architecture
194 - libfdt Library files to support flattened device trees
195 - net Networking code
196 - post Power On Self Test
197 - rtc Real Time Clock drivers
198 - tools Tools to build S-Record or U-Boot images, etc.
200 Software Configuration:
201 =======================
203 Configuration is usually done using C preprocessor defines; the
204 rationale behind that is to avoid dead code whenever possible.
206 There are two classes of configuration variables:
208 * Configuration _OPTIONS_:
209 These are selectable by the user and have names beginning with
212 * Configuration _SETTINGS_:
213 These depend on the hardware etc. and should not be meddled with if
214 you don't know what you're doing; they have names beginning with
217 Later we will add a configuration tool - probably similar to or even
218 identical to what's used for the Linux kernel. Right now, we have to
219 do the configuration by hand, which means creating some symbolic
220 links and editing some configuration files. We use the TQM8xxL boards
224 Selection of Processor Architecture and Board Type:
225 ---------------------------------------------------
227 For all supported boards there are ready-to-use default
228 configurations available; just type "make <board_name>_config".
230 Example: For a TQM823L module type:
235 For the Cogent platform, you need to specify the CPU type as well;
236 e.g. "make cogent_mpc8xx_config". And also configure the cogent
237 directory according to the instructions in cogent/README.
240 Configuration Options:
241 ----------------------
243 Configuration depends on the combination of board and CPU type; all
244 such information is kept in a configuration file
245 "include/configs/<board_name>.h".
247 Example: For a TQM823L module, all configuration settings are in
248 "include/configs/TQM823L.h".
251 Many of the options are named exactly as the corresponding Linux
252 kernel configuration options. The intention is to make it easier to
253 build a config tool - later.
256 The following options need to be configured:
258 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
260 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
262 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
263 Define exactly one, e.g. CONFIG_ATSTK1002
265 - CPU Module Type: (if CONFIG_COGENT is defined)
266 Define exactly one of
268 --- FIXME --- not tested yet:
269 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
270 CONFIG_CMA287_23, CONFIG_CMA287_50
272 - Motherboard Type: (if CONFIG_COGENT is defined)
273 Define exactly one of
274 CONFIG_CMA101, CONFIG_CMA102
276 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
277 Define one or more of
280 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
281 Define one or more of
282 CONFIG_LCD_HEARTBEAT - update a character position on
283 the LCD display every second with
286 - Board flavour: (if CONFIG_MPC8260ADS is defined)
289 CONFIG_SYS_8260ADS - original MPC8260ADS
290 CONFIG_SYS_8266ADS - MPC8266ADS
291 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
292 CONFIG_SYS_8272ADS - MPC8272ADS
294 - MPC824X Family Member (if CONFIG_MPC824X is defined)
295 Define exactly one of
296 CONFIG_MPC8240, CONFIG_MPC8245
298 - 8xx CPU Options: (if using an MPC8xx CPU)
299 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
300 get_gclk_freq() cannot work
301 e.g. if there is no 32KHz
302 reference PIT/RTC clock
303 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
306 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
307 CONFIG_SYS_8xx_CPUCLK_MIN
308 CONFIG_SYS_8xx_CPUCLK_MAX
309 CONFIG_8xx_CPUCLK_DEFAULT
310 See doc/README.MPC866
312 CONFIG_SYS_MEASURE_CPUCLK
314 Define this to measure the actual CPU clock instead
315 of relying on the correctness of the configured
316 values. Mostly useful for board bringup to make sure
317 the PLL is locked at the intended frequency. Note
318 that this requires a (stable) reference clock (32 kHz
319 RTC clock or CONFIG_SYS_8XX_XIN)
321 - Intel Monahans options:
322 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
324 Defines the Monahans run mode to oscillator
325 ratio. Valid values are 8, 16, 24, 31. The core
326 frequency is this value multiplied by 13 MHz.
328 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
330 Defines the Monahans turbo mode to oscillator
331 ratio. Valid values are 1 (default if undefined) and
332 2. The core frequency as calculated above is multiplied
335 - Linux Kernel Interface:
338 U-Boot stores all clock information in Hz
339 internally. For binary compatibility with older Linux
340 kernels (which expect the clocks passed in the
341 bd_info data to be in MHz) the environment variable
342 "clocks_in_mhz" can be defined so that U-Boot
343 converts clock data to MHZ before passing it to the
345 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
346 "clocks_in_mhz=1" is automatically included in the
349 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
351 When transferring memsize parameter to linux, some versions
352 expect it to be in bytes, others in MB.
353 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
357 New kernel versions are expecting firmware settings to be
358 passed using flattened device trees (based on open firmware
362 * New libfdt-based support
363 * Adds the "fdt" command
364 * The bootm command automatically updates the fdt
366 OF_CPU - The proper name of the cpus node.
367 OF_SOC - The proper name of the soc node.
368 OF_TBCLK - The timebase frequency.
369 OF_STDOUT_PATH - The path to the console device
371 boards with QUICC Engines require OF_QE to set UCC MAC
374 CONFIG_OF_BOARD_SETUP
376 Board code has addition modification that it wants to make
377 to the flat device tree before handing it off to the kernel
381 This define fills in the correct boot CPU in the boot
382 param header, the default value is zero if undefined.
384 - vxWorks boot parameters:
386 bootvx constructs a valid bootline using the following
387 environments variables: bootfile, ipaddr, serverip, hostname.
388 It loads the vxWorks image pointed bootfile.
390 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
391 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
392 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
393 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
395 CONFIG_SYS_VXWORKS_ADD_PARAMS
397 Add it at the end of the bootline. E.g "u=username pw=secret"
399 Note: If a "bootargs" environment is defined, it will overwride
400 the defaults discussed just above.
405 Define this if you want support for Amba PrimeCell PL010 UARTs.
409 Define this if you want support for Amba PrimeCell PL011 UARTs.
413 If you have Amba PrimeCell PL011 UARTs, set this variable to
414 the clock speed of the UARTs.
418 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
419 define this to a list of base addresses for each (supported)
420 port. See e.g. include/configs/versatile.h
424 Depending on board, define exactly one serial port
425 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
426 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
427 console by defining CONFIG_8xx_CONS_NONE
429 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
430 port routines must be defined elsewhere
431 (i.e. serial_init(), serial_getc(), ...)
434 Enables console device for a color framebuffer. Needs following
435 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
436 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
438 VIDEO_HW_RECTFILL graphic chip supports
441 VIDEO_HW_BITBLT graphic chip supports
442 bit-blit (cf. smiLynxEM)
443 VIDEO_VISIBLE_COLS visible pixel columns
445 VIDEO_VISIBLE_ROWS visible pixel rows
446 VIDEO_PIXEL_SIZE bytes per pixel
447 VIDEO_DATA_FORMAT graphic data format
448 (0-5, cf. cfb_console.c)
449 VIDEO_FB_ADRS framebuffer address
450 VIDEO_KBD_INIT_FCT keyboard int fct
451 (i.e. i8042_kbd_init())
452 VIDEO_TSTC_FCT test char fct
454 VIDEO_GETC_FCT get char fct
456 CONFIG_CONSOLE_CURSOR cursor drawing on/off
457 (requires blink timer
459 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
460 CONFIG_CONSOLE_TIME display time/date info in
462 (requires CONFIG_CMD_DATE)
463 CONFIG_VIDEO_LOGO display Linux logo in
465 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
466 linux_logo.h for logo.
467 Requires CONFIG_VIDEO_LOGO
468 CONFIG_CONSOLE_EXTRA_INFO
469 additional board info beside
472 When CONFIG_CFB_CONSOLE is defined, video console is
473 default i/o. Serial console can be forced with
474 environment 'console=serial'.
476 When CONFIG_SILENT_CONSOLE is defined, all console
477 messages (by U-Boot and Linux!) can be silenced with
478 the "silent" environment variable. See
479 doc/README.silent for more information.
482 CONFIG_BAUDRATE - in bps
483 Select one of the baudrates listed in
484 CONFIG_SYS_BAUDRATE_TABLE, see below.
485 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
487 - Interrupt driven serial port input:
488 CONFIG_SERIAL_SOFTWARE_FIFO
491 Use an interrupt handler for receiving data on the
492 serial port. It also enables using hardware handshake
493 (RTS/CTS) and UART's built-in FIFO. Set the number of
494 bytes the interrupt driven input buffer should have.
496 Leave undefined to disable this feature, including
497 disable the buffer and hardware handshake.
499 - Console UART Number:
503 If defined internal UART1 (and not UART0) is used
504 as default U-Boot console.
506 - Boot Delay: CONFIG_BOOTDELAY - in seconds
507 Delay before automatically booting the default image;
508 set to -1 to disable autoboot.
510 See doc/README.autoboot for these options that
511 work with CONFIG_BOOTDELAY. None are required.
512 CONFIG_BOOT_RETRY_TIME
513 CONFIG_BOOT_RETRY_MIN
514 CONFIG_AUTOBOOT_KEYED
515 CONFIG_AUTOBOOT_PROMPT
516 CONFIG_AUTOBOOT_DELAY_STR
517 CONFIG_AUTOBOOT_STOP_STR
518 CONFIG_AUTOBOOT_DELAY_STR2
519 CONFIG_AUTOBOOT_STOP_STR2
520 CONFIG_ZERO_BOOTDELAY_CHECK
521 CONFIG_RESET_TO_RETRY
525 Only needed when CONFIG_BOOTDELAY is enabled;
526 define a command string that is automatically executed
527 when no character is read on the console interface
528 within "Boot Delay" after reset.
531 This can be used to pass arguments to the bootm
532 command. The value of CONFIG_BOOTARGS goes into the
533 environment value "bootargs".
535 CONFIG_RAMBOOT and CONFIG_NFSBOOT
536 The value of these goes into the environment as
537 "ramboot" and "nfsboot" respectively, and can be used
538 as a convenience, when switching between booting from
544 When this option is #defined, the existence of the
545 environment variable "preboot" will be checked
546 immediately before starting the CONFIG_BOOTDELAY
547 countdown and/or running the auto-boot command resp.
548 entering interactive mode.
550 This feature is especially useful when "preboot" is
551 automatically generated or modified. For an example
552 see the LWMON board specific code: here "preboot" is
553 modified when the user holds down a certain
554 combination of keys on the (special) keyboard when
557 - Serial Download Echo Mode:
559 If defined to 1, all characters received during a
560 serial download (using the "loads" command) are
561 echoed back. This might be needed by some terminal
562 emulations (like "cu"), but may as well just take
563 time on others. This setting #define's the initial
564 value of the "loads_echo" environment variable.
566 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
568 Select one of the baudrates listed in
569 CONFIG_SYS_BAUDRATE_TABLE, see below.
572 Monitor commands can be included or excluded
573 from the build by using the #include files
574 "config_cmd_all.h" and #undef'ing unwanted
575 commands, or using "config_cmd_default.h"
576 and augmenting with additional #define's
579 The default command configuration includes all commands
580 except those marked below with a "*".
582 CONFIG_CMD_ASKENV * ask for env variable
583 CONFIG_CMD_AUTOSCRIPT Autoscript Support
584 CONFIG_CMD_BDI bdinfo
585 CONFIG_CMD_BEDBUG * Include BedBug Debugger
586 CONFIG_CMD_BMP * BMP support
587 CONFIG_CMD_BSP * Board specific commands
588 CONFIG_CMD_BOOTD bootd
589 CONFIG_CMD_CACHE * icache, dcache
590 CONFIG_CMD_CONSOLE coninfo
591 CONFIG_CMD_DATE * support for RTC, date/time...
592 CONFIG_CMD_DHCP * DHCP support
593 CONFIG_CMD_DIAG * Diagnostics
594 CONFIG_CMD_DOC * Disk-On-Chip Support
595 CONFIG_CMD_DTT * Digital Therm and Thermostat
596 CONFIG_CMD_ECHO echo arguments
597 CONFIG_CMD_EEPROM * EEPROM read/write support
598 CONFIG_CMD_ELF * bootelf, bootvx
599 CONFIG_CMD_ENV saveenv
600 CONFIG_CMD_FDC * Floppy Disk Support
601 CONFIG_CMD_FAT * FAT partition support
602 CONFIG_CMD_FDOS * Dos diskette Support
603 CONFIG_CMD_FLASH flinfo, erase, protect
604 CONFIG_CMD_FPGA FPGA device initialization support
605 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
606 CONFIG_CMD_I2C * I2C serial bus support
607 CONFIG_CMD_IDE * IDE harddisk support
608 CONFIG_CMD_IMI iminfo
609 CONFIG_CMD_IMLS List all found images
610 CONFIG_CMD_IMMAP * IMMR dump support
611 CONFIG_CMD_IRQ * irqinfo
612 CONFIG_CMD_ITEST Integer/string test of 2 values
613 CONFIG_CMD_JFFS2 * JFFS2 Support
614 CONFIG_CMD_KGDB * kgdb
615 CONFIG_CMD_LOADB loadb
616 CONFIG_CMD_LOADS loads
617 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
619 CONFIG_CMD_MISC Misc functions like sleep etc
620 CONFIG_CMD_MMC * MMC memory mapped support
621 CONFIG_CMD_MII * MII utility commands
622 CONFIG_CMD_NAND * NAND support
623 CONFIG_CMD_NET bootp, tftpboot, rarpboot
624 CONFIG_CMD_PCI * pciinfo
625 CONFIG_CMD_PCMCIA * PCMCIA support
626 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
628 CONFIG_CMD_PORTIO * Port I/O
629 CONFIG_CMD_REGINFO * Register dump
630 CONFIG_CMD_RUN run command in env variable
631 CONFIG_CMD_SAVES * save S record dump
632 CONFIG_CMD_SCSI * SCSI Support
633 CONFIG_CMD_SDRAM * print SDRAM configuration information
634 (requires CONFIG_CMD_I2C)
635 CONFIG_CMD_SETGETDCR Support for DCR Register access
637 CONFIG_CMD_SPI * SPI serial bus support
638 CONFIG_CMD_USB * USB support
639 CONFIG_CMD_VFD * VFD support (TRAB)
640 CONFIG_CMD_CDP * Cisco Discover Protocol support
641 CONFIG_CMD_FSL * Microblaze FSL support
644 EXAMPLE: If you want all functions except of network
645 support you can write:
647 #include "config_cmd_all.h"
648 #undef CONFIG_CMD_NET
651 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
653 Note: Don't enable the "icache" and "dcache" commands
654 (configuration option CONFIG_CMD_CACHE) unless you know
655 what you (and your U-Boot users) are doing. Data
656 cache cannot be enabled on systems like the 8xx or
657 8260 (where accesses to the IMMR region must be
658 uncached), and it cannot be disabled on all other
659 systems where we (mis-) use the data cache to hold an
660 initial stack and some data.
663 XXX - this list needs to get updated!
667 If this variable is defined, it enables watchdog
668 support. There must be support in the platform specific
669 code for a watchdog. For the 8xx and 8260 CPUs, the
670 SIU Watchdog feature is enabled in the SYPCR
674 CONFIG_VERSION_VARIABLE
675 If this variable is defined, an environment variable
676 named "ver" is created by U-Boot showing the U-Boot
677 version as printed by the "version" command.
678 This variable is readonly.
682 When CONFIG_CMD_DATE is selected, the type of the RTC
683 has to be selected, too. Define exactly one of the
686 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
687 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
688 CONFIG_RTC_MC13783 - use MC13783 RTC
689 CONFIG_RTC_MC146818 - use MC146818 RTC
690 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
691 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
692 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
693 CONFIG_RTC_DS164x - use Dallas DS164x RTC
694 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
695 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
696 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
698 Note that if the RTC uses I2C, then the I2C interface
699 must also be configured. See I2C Support, below.
703 When CONFIG_TIMESTAMP is selected, the timestamp
704 (date and time) of an image is printed by image
705 commands like bootm or iminfo. This option is
706 automatically enabled when you select CONFIG_CMD_DATE .
709 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
710 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
712 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
713 CONFIG_CMD_SCSI) you must configure support for at
714 least one partition type as well.
717 CONFIG_IDE_RESET_ROUTINE - this is defined in several
718 board configurations files but used nowhere!
720 CONFIG_IDE_RESET - is this is defined, IDE Reset will
721 be performed by calling the function
722 ide_set_reset(int reset)
723 which has to be defined in a board specific file
728 Set this to enable ATAPI support.
733 Set this to enable support for disks larger than 137GB
734 Also look at CONFIG_SYS_64BIT_LBA ,CONFIG_SYS_64BIT_VSPRINTF and CONFIG_SYS_64BIT_STRTOUL
735 Whithout these , LBA48 support uses 32bit variables and will 'only'
736 support disks up to 2.1TB.
738 CONFIG_SYS_64BIT_LBA:
739 When enabled, makes the IDE subsystem use 64bit sector addresses.
743 At the moment only there is only support for the
744 SYM53C8XX SCSI controller; define
745 CONFIG_SCSI_SYM53C8XX to enable it.
747 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
748 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
749 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
750 maximum numbers of LUNs, SCSI ID's and target
752 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
754 - NETWORK Support (PCI):
756 Support for Intel 8254x gigabit chips.
758 CONFIG_E1000_FALLBACK_MAC
759 default MAC for empty EEPROM after production.
762 Support for Intel 82557/82559/82559ER chips.
763 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
764 write routine for first time initialisation.
767 Support for Digital 2114x chips.
768 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
769 modem chip initialisation (KS8761/QS6611).
772 Support for National dp83815 chips.
775 Support for National dp8382[01] gigabit chips.
777 - NETWORK Support (other):
779 CONFIG_DRIVER_LAN91C96
780 Support for SMSC's LAN91C96 chips.
783 Define this to hold the physical address
784 of the LAN91C96's I/O space
786 CONFIG_LAN91C96_USE_32_BIT
787 Define this to enable 32 bit addressing
789 CONFIG_DRIVER_SMC91111
790 Support for SMSC's LAN91C111 chip
793 Define this to hold the physical address
794 of the device (I/O space)
796 CONFIG_SMC_USE_32_BIT
797 Define this if data bus is 32 bits
799 CONFIG_SMC_USE_IOFUNCS
800 Define this to use i/o functions instead of macros
801 (some hardware wont work with macros)
803 CONFIG_DRIVER_SMC911X
804 Support for SMSC's LAN911x and LAN921x chips
806 CONFIG_DRIVER_SMC911X_BASE
807 Define this to hold the physical address
808 of the device (I/O space)
810 CONFIG_DRIVER_SMC911X_32_BIT
811 Define this if data bus is 32 bits
813 CONFIG_DRIVER_SMC911X_16_BIT
814 Define this if data bus is 16 bits. If your processor
815 automatically converts one 32 bit word to two 16 bit
816 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
819 At the moment only the UHCI host controller is
820 supported (PIP405, MIP405, MPC5200); define
821 CONFIG_USB_UHCI to enable it.
822 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
823 and define CONFIG_USB_STORAGE to enable the USB
826 Supported are USB Keyboards and USB Floppy drives
828 MPC5200 USB requires additional defines:
830 for 528 MHz Clock: 0x0001bbbb
832 for differential drivers: 0x00001000
833 for single ended drivers: 0x00005000
834 CONFIG_SYS_USB_EVENT_POLL
835 May be defined to allow interrupt polling
836 instead of using asynchronous interrupts
839 Define the below if you wish to use the USB console.
840 Once firmware is rebuilt from a serial console issue the
841 command "setenv stdin usbtty; setenv stdout usbtty" and
842 attach your USB cable. The Unix command "dmesg" should print
843 it has found a new device. The environment variable usbtty
844 can be set to gserial or cdc_acm to enable your device to
845 appear to a USB host as a Linux gserial device or a
846 Common Device Class Abstract Control Model serial device.
847 If you select usbtty = gserial you should be able to enumerate
849 # modprobe usbserial vendor=0xVendorID product=0xProductID
850 else if using cdc_acm, simply setting the environment
851 variable usbtty to be cdc_acm should suffice. The following
852 might be defined in YourBoardName.h
855 Define this to build a UDC device
858 Define this to have a tty type of device available to
859 talk to the UDC device
861 CONFIG_SYS_CONSOLE_IS_IN_ENV
862 Define this if you want stdin, stdout &/or stderr to
866 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
867 Derive USB clock from external clock "blah"
868 - CONFIG_SYS_USB_EXTC_CLK 0x02
870 CONFIG_SYS_USB_BRG_CLK 0xBLAH
871 Derive USB clock from brgclk
872 - CONFIG_SYS_USB_BRG_CLK 0x04
874 If you have a USB-IF assigned VendorID then you may wish to
875 define your own vendor specific values either in BoardName.h
876 or directly in usbd_vendor_info.h. If you don't define
877 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
878 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
879 should pretend to be a Linux device to it's target host.
881 CONFIG_USBD_MANUFACTURER
882 Define this string as the name of your company for
883 - CONFIG_USBD_MANUFACTURER "my company"
885 CONFIG_USBD_PRODUCT_NAME
886 Define this string as the name of your product
887 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
890 Define this as your assigned Vendor ID from the USB
891 Implementors Forum. This *must* be a genuine Vendor ID
892 to avoid polluting the USB namespace.
893 - CONFIG_USBD_VENDORID 0xFFFF
895 CONFIG_USBD_PRODUCTID
896 Define this as the unique Product ID
898 - CONFIG_USBD_PRODUCTID 0xFFFF
902 The MMC controller on the Intel PXA is supported. To
903 enable this define CONFIG_MMC. The MMC can be
904 accessed from the boot prompt by mapping the device
905 to physical memory similar to flash. Command line is
906 enabled with CONFIG_CMD_MMC. The MMC driver also works with
907 the FAT fs. This is enabled with CONFIG_CMD_FAT.
909 - Journaling Flash filesystem support:
910 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
911 CONFIG_JFFS2_NAND_DEV
912 Define these for a default partition on a NAND device
914 CONFIG_SYS_JFFS2_FIRST_SECTOR,
915 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
916 Define these for a default partition on a NOR device
918 CONFIG_SYS_JFFS_CUSTOM_PART
919 Define this to create an own partition. You have to provide a
920 function struct part_info* jffs2_part_info(int part_num)
922 If you define only one JFFS2 partition you may also want to
923 #define CONFIG_SYS_JFFS_SINGLE_PART 1
924 to disable the command chpart. This is the default when you
925 have not defined a custom partition
930 Define this to enable standard (PC-Style) keyboard
934 Standard PC keyboard driver with US (is default) and
935 GERMAN key layout (switch via environment 'keymap=de') support.
936 Export function i8042_kbd_init, i8042_tstc and i8042_getc
937 for cfb_console. Supports cursor blinking.
942 Define this to enable video support (for output to
947 Enable Chips & Technologies 69000 Video chip
949 CONFIG_VIDEO_SMI_LYNXEM
950 Enable Silicon Motion SMI 712/710/810 Video chip. The
951 video output is selected via environment 'videoout'
952 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
955 For the CT69000 and SMI_LYNXEM drivers, videomode is
956 selected via environment 'videomode'. Two different ways
958 - "videomode=num" 'num' is a standard LiLo mode numbers.
959 Following standard modes are supported (* is default):
961 Colors 640x480 800x600 1024x768 1152x864 1280x1024
962 -------------+---------------------------------------------
963 8 bits | 0x301* 0x303 0x305 0x161 0x307
964 15 bits | 0x310 0x313 0x316 0x162 0x319
965 16 bits | 0x311 0x314 0x317 0x163 0x31A
966 24 bits | 0x312 0x315 0x318 ? 0x31B
967 -------------+---------------------------------------------
968 (i.e. setenv videomode 317; saveenv; reset;)
970 - "videomode=bootargs" all the video parameters are parsed
971 from the bootargs. (See drivers/video/videomodes.c)
974 CONFIG_VIDEO_SED13806
975 Enable Epson SED13806 driver. This driver supports 8bpp
976 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
977 or CONFIG_VIDEO_SED13806_16BPP
982 Define this to enable a custom keyboard support.
983 This simply calls drv_keyboard_init() which must be
984 defined in your board-specific files.
985 The only board using this so far is RBC823.
987 - LCD Support: CONFIG_LCD
989 Define this to enable LCD support (for output to LCD
990 display); also select one of the supported displays
991 by defining one of these:
995 HITACHI TX09D70VM1CCA, 3.5", 240x320.
997 CONFIG_NEC_NL6448AC33:
999 NEC NL6448AC33-18. Active, color, single scan.
1001 CONFIG_NEC_NL6448BC20
1003 NEC NL6448BC20-08. 6.5", 640x480.
1004 Active, color, single scan.
1006 CONFIG_NEC_NL6448BC33_54
1008 NEC NL6448BC33-54. 10.4", 640x480.
1009 Active, color, single scan.
1013 Sharp 320x240. Active, color, single scan.
1014 It isn't 16x9, and I am not sure what it is.
1016 CONFIG_SHARP_LQ64D341
1018 Sharp LQ64D341 display, 640x480.
1019 Active, color, single scan.
1023 HLD1045 display, 640x480.
1024 Active, color, single scan.
1028 Optrex CBL50840-2 NF-FW 99 22 M5
1030 Hitachi LMG6912RPFC-00T
1034 320x240. Black & white.
1036 Normally display is black on white background; define
1037 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1039 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1041 If this option is set, the environment is checked for
1042 a variable "splashimage". If found, the usual display
1043 of logo, copyright and system information on the LCD
1044 is suppressed and the BMP image at the address
1045 specified in "splashimage" is loaded instead. The
1046 console is redirected to the "nulldev", too. This
1047 allows for a "silent" boot where a splash screen is
1048 loaded very quickly after power-on.
1050 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1052 If this option is set, additionally to standard BMP
1053 images, gzipped BMP images can be displayed via the
1054 splashscreen support or the bmp command.
1056 - Compression support:
1059 If this option is set, support for bzip2 compressed
1060 images is included. If not, only uncompressed and gzip
1061 compressed images are supported.
1063 NOTE: the bzip2 algorithm requires a lot of RAM, so
1064 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1069 If this option is set, support for lzma compressed
1072 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1073 requires an amount of dynamic memory that is given by the
1076 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1078 Where lc and lp stand for, respectively, Literal context bits
1079 and Literal pos bits.
1081 This value is upper-bounded by 14MB in the worst case. Anyway,
1082 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1083 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1084 a very small buffer.
1086 Use the lzmainfo tool to determinate the lc and lp values and
1087 then calculate the amount of needed dynamic memory (ensuring
1088 the appropriate CONFIG_SYS_MALLOC_LEN value).
1093 The address of PHY on MII bus.
1095 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1097 The clock frequency of the MII bus
1101 If this option is set, support for speed/duplex
1102 detection of gigabit PHY is included.
1104 CONFIG_PHY_RESET_DELAY
1106 Some PHY like Intel LXT971A need extra delay after
1107 reset before any MII register access is possible.
1108 For such PHY, set this option to the usec delay
1109 required. (minimum 300usec for LXT971A)
1111 CONFIG_PHY_CMD_DELAY (ppc4xx)
1113 Some PHY like Intel LXT971A need extra delay after
1114 command issued before MII status register can be read
1124 Define a default value for Ethernet address to use
1125 for the respective Ethernet interface, in case this
1126 is not determined automatically.
1131 Define a default value for the IP address to use for
1132 the default Ethernet interface, in case this is not
1133 determined through e.g. bootp.
1135 - Server IP address:
1138 Defines a default value for the IP address of a TFTP
1139 server to contact when using the "tftboot" command.
1141 - Multicast TFTP Mode:
1144 Defines whether you want to support multicast TFTP as per
1145 rfc-2090; for example to work with atftp. Lets lots of targets
1146 tftp down the same boot image concurrently. Note: the Ethernet
1147 driver in use must provide a function: mcast() to join/leave a
1150 CONFIG_BOOTP_RANDOM_DELAY
1151 - BOOTP Recovery Mode:
1152 CONFIG_BOOTP_RANDOM_DELAY
1154 If you have many targets in a network that try to
1155 boot using BOOTP, you may want to avoid that all
1156 systems send out BOOTP requests at precisely the same
1157 moment (which would happen for instance at recovery
1158 from a power failure, when all systems will try to
1159 boot, thus flooding the BOOTP server. Defining
1160 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1161 inserted before sending out BOOTP requests. The
1162 following delays are inserted then:
1164 1st BOOTP request: delay 0 ... 1 sec
1165 2nd BOOTP request: delay 0 ... 2 sec
1166 3rd BOOTP request: delay 0 ... 4 sec
1168 BOOTP requests: delay 0 ... 8 sec
1170 - DHCP Advanced Options:
1171 You can fine tune the DHCP functionality by defining
1172 CONFIG_BOOTP_* symbols:
1174 CONFIG_BOOTP_SUBNETMASK
1175 CONFIG_BOOTP_GATEWAY
1176 CONFIG_BOOTP_HOSTNAME
1177 CONFIG_BOOTP_NISDOMAIN
1178 CONFIG_BOOTP_BOOTPATH
1179 CONFIG_BOOTP_BOOTFILESIZE
1182 CONFIG_BOOTP_SEND_HOSTNAME
1183 CONFIG_BOOTP_NTPSERVER
1184 CONFIG_BOOTP_TIMEOFFSET
1185 CONFIG_BOOTP_VENDOREX
1187 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1188 environment variable, not the BOOTP server.
1190 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1191 serverip from a DHCP server, it is possible that more
1192 than one DNS serverip is offered to the client.
1193 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1194 serverip will be stored in the additional environment
1195 variable "dnsip2". The first DNS serverip is always
1196 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1199 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1200 to do a dynamic update of a DNS server. To do this, they
1201 need the hostname of the DHCP requester.
1202 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1203 of the "hostname" environment variable is passed as
1204 option 12 to the DHCP server.
1206 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1208 A 32bit value in microseconds for a delay between
1209 receiving a "DHCP Offer" and sending the "DHCP Request".
1210 This fixes a problem with certain DHCP servers that don't
1211 respond 100% of the time to a "DHCP request". E.g. On an
1212 AT91RM9200 processor running at 180MHz, this delay needed
1213 to be *at least* 15,000 usec before a Windows Server 2003
1214 DHCP server would reply 100% of the time. I recommend at
1215 least 50,000 usec to be safe. The alternative is to hope
1216 that one of the retries will be successful but note that
1217 the DHCP timeout and retry process takes a longer than
1221 CONFIG_CDP_DEVICE_ID
1223 The device id used in CDP trigger frames.
1225 CONFIG_CDP_DEVICE_ID_PREFIX
1227 A two character string which is prefixed to the MAC address
1232 A printf format string which contains the ascii name of
1233 the port. Normally is set to "eth%d" which sets
1234 eth0 for the first Ethernet, eth1 for the second etc.
1236 CONFIG_CDP_CAPABILITIES
1238 A 32bit integer which indicates the device capabilities;
1239 0x00000010 for a normal host which does not forwards.
1243 An ascii string containing the version of the software.
1247 An ascii string containing the name of the platform.
1251 A 32bit integer sent on the trigger.
1253 CONFIG_CDP_POWER_CONSUMPTION
1255 A 16bit integer containing the power consumption of the
1256 device in .1 of milliwatts.
1258 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1260 A byte containing the id of the VLAN.
1262 - Status LED: CONFIG_STATUS_LED
1264 Several configurations allow to display the current
1265 status using a LED. For instance, the LED will blink
1266 fast while running U-Boot code, stop blinking as
1267 soon as a reply to a BOOTP request was received, and
1268 start blinking slow once the Linux kernel is running
1269 (supported by a status LED driver in the Linux
1270 kernel). Defining CONFIG_STATUS_LED enables this
1273 - CAN Support: CONFIG_CAN_DRIVER
1275 Defining CONFIG_CAN_DRIVER enables CAN driver support
1276 on those systems that support this (optional)
1277 feature, like the TQM8xxL modules.
1279 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1281 These enable I2C serial bus commands. Defining either of
1282 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1283 include the appropriate I2C driver for the selected CPU.
1285 This will allow you to use i2c commands at the u-boot
1286 command line (as long as you set CONFIG_CMD_I2C in
1287 CONFIG_COMMANDS) and communicate with i2c based realtime
1288 clock chips. See common/cmd_i2c.c for a description of the
1289 command line interface.
1291 CONFIG_I2C_CMD_TREE is a recommended option that places
1292 all I2C commands under a single 'i2c' root command. The
1293 older 'imm', 'imd', 'iprobe' etc. commands are considered
1294 deprecated and may disappear in the future.
1296 CONFIG_HARD_I2C selects a hardware I2C controller.
1298 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1299 bit-banging) driver instead of CPM or similar hardware
1302 There are several other quantities that must also be
1303 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1305 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1306 to be the frequency (in Hz) at which you wish your i2c bus
1307 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1308 the CPU's i2c node address).
1310 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1311 sets the CPU up as a master node and so its address should
1312 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1313 p.16-473). So, set CONFIG_SYS_I2C_SLAVE to 0.
1315 That's all that's required for CONFIG_HARD_I2C.
1317 If you use the software i2c interface (CONFIG_SOFT_I2C)
1318 then the following macros need to be defined (examples are
1319 from include/configs/lwmon.h):
1323 (Optional). Any commands necessary to enable the I2C
1324 controller or configure ports.
1326 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1330 (Only for MPC8260 CPU). The I/O port to use (the code
1331 assumes both bits are on the same port). Valid values
1332 are 0..3 for ports A..D.
1336 The code necessary to make the I2C data line active
1337 (driven). If the data line is open collector, this
1340 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1344 The code necessary to make the I2C data line tri-stated
1345 (inactive). If the data line is open collector, this
1348 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1352 Code that returns TRUE if the I2C data line is high,
1355 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1359 If <bit> is TRUE, sets the I2C data line high. If it
1360 is FALSE, it clears it (low).
1362 eg: #define I2C_SDA(bit) \
1363 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1364 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1368 If <bit> is TRUE, sets the I2C clock line high. If it
1369 is FALSE, it clears it (low).
1371 eg: #define I2C_SCL(bit) \
1372 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1373 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1377 This delay is invoked four times per clock cycle so this
1378 controls the rate of data transfer. The data rate thus
1379 is 1 / (I2C_DELAY * 4). Often defined to be something
1382 #define I2C_DELAY udelay(2)
1384 CONFIG_SYS_I2C_INIT_BOARD
1386 When a board is reset during an i2c bus transfer
1387 chips might think that the current transfer is still
1388 in progress. On some boards it is possible to access
1389 the i2c SCLK line directly, either by using the
1390 processor pin as a GPIO or by having a second pin
1391 connected to the bus. If this option is defined a
1392 custom i2c_init_board() routine in boards/xxx/board.c
1393 is run early in the boot sequence.
1395 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1397 This option enables configuration of bi_iic_fast[] flags
1398 in u-boot bd_info structure based on u-boot environment
1399 variable "i2cfast". (see also i2cfast)
1401 CONFIG_I2C_MULTI_BUS
1403 This option allows the use of multiple I2C buses, each of which
1404 must have a controller. At any point in time, only one bus is
1405 active. To switch to a different bus, use the 'i2c dev' command.
1406 Note that bus numbering is zero-based.
1408 CONFIG_SYS_I2C_NOPROBES
1410 This option specifies a list of I2C devices that will be skipped
1411 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1412 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1413 pairs. Otherwise, specify a 1D array of device addresses
1416 #undef CONFIG_I2C_MULTI_BUS
1417 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1419 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1421 #define CONFIG_I2C_MULTI_BUS
1422 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1424 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1426 CONFIG_SYS_SPD_BUS_NUM
1428 If defined, then this indicates the I2C bus number for DDR SPD.
1429 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1431 CONFIG_SYS_RTC_BUS_NUM
1433 If defined, then this indicates the I2C bus number for the RTC.
1434 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1436 CONFIG_SYS_DTT_BUS_NUM
1438 If defined, then this indicates the I2C bus number for the DTT.
1439 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1441 CONFIG_SYS_I2C_DTT_ADDR:
1443 If defined, specifies the I2C address of the DTT device.
1444 If not defined, then U-Boot uses predefined value for
1445 specified DTT device.
1449 Define this option if you want to use Freescale's I2C driver in
1450 drivers/i2c/fsl_i2c.c.
1454 Define this option if you have I2C devices reached over 1 .. n
1455 I2C Muxes like the pca9544a. This option addes a new I2C
1456 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1457 new I2C Bus to the existing I2C Busses. If you select the
1458 new Bus with "i2c dev", u-bbot sends first the commandos for
1459 the muxes to activate this new "bus".
1461 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1465 Adding a new I2C Bus reached over 2 pca9544a muxes
1466 The First mux with address 70 and channel 6
1467 The Second mux with address 71 and channel 4
1469 => i2c bus pca9544a:70:6:pca9544a:71:4
1471 Use the "i2c bus" command without parameter, to get a list
1472 of I2C Busses with muxes:
1475 Busses reached over muxes:
1477 reached over Mux(es):
1480 reached over Mux(es):
1485 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1486 u-boot sends First the Commando to the mux@70 to enable
1487 channel 6, and then the Commando to the mux@71 to enable
1490 After that, you can use the "normal" i2c commands as
1491 usual, to communicate with your I2C devices behind
1494 This option is actually implemented for the bitbanging
1495 algorithm in common/soft_i2c.c and for the Hardware I2C
1496 Bus on the MPC8260. But it should be not so difficult
1497 to add this option to other architectures.
1500 - SPI Support: CONFIG_SPI
1502 Enables SPI driver (so far only tested with
1503 SPI EEPROM, also an instance works with Crystal A/D and
1504 D/As on the SACSng board)
1508 Enables extended (16-bit) SPI EEPROM addressing.
1509 (symmetrical to CONFIG_I2C_X)
1513 Enables a software (bit-bang) SPI driver rather than
1514 using hardware support. This is a general purpose
1515 driver that only requires three general I/O port pins
1516 (two outputs, one input) to function. If this is
1517 defined, the board configuration must define several
1518 SPI configuration items (port pins to use, etc). For
1519 an example, see include/configs/sacsng.h.
1523 Enables a hardware SPI driver for general-purpose reads
1524 and writes. As with CONFIG_SOFT_SPI, the board configuration
1525 must define a list of chip-select function pointers.
1526 Currently supported on some MPC8xxx processors. For an
1527 example, see include/configs/mpc8349emds.h.
1531 Enables the driver for the SPI controllers on i.MX and MXC
1532 SoCs. Currently only i.MX31 is supported.
1534 - FPGA Support: CONFIG_FPGA
1536 Enables FPGA subsystem.
1538 CONFIG_FPGA_<vendor>
1540 Enables support for specific chip vendors.
1543 CONFIG_FPGA_<family>
1545 Enables support for FPGA family.
1546 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1550 Specify the number of FPGA devices to support.
1552 CONFIG_SYS_FPGA_PROG_FEEDBACK
1554 Enable printing of hash marks during FPGA configuration.
1556 CONFIG_SYS_FPGA_CHECK_BUSY
1558 Enable checks on FPGA configuration interface busy
1559 status by the configuration function. This option
1560 will require a board or device specific function to
1565 If defined, a function that provides delays in the FPGA
1566 configuration driver.
1568 CONFIG_SYS_FPGA_CHECK_CTRLC
1569 Allow Control-C to interrupt FPGA configuration
1571 CONFIG_SYS_FPGA_CHECK_ERROR
1573 Check for configuration errors during FPGA bitfile
1574 loading. For example, abort during Virtex II
1575 configuration if the INIT_B line goes low (which
1576 indicated a CRC error).
1578 CONFIG_SYS_FPGA_WAIT_INIT
1580 Maximum time to wait for the INIT_B line to deassert
1581 after PROB_B has been deasserted during a Virtex II
1582 FPGA configuration sequence. The default time is 500
1585 CONFIG_SYS_FPGA_WAIT_BUSY
1587 Maximum time to wait for BUSY to deassert during
1588 Virtex II FPGA configuration. The default is 5 ms.
1590 CONFIG_SYS_FPGA_WAIT_CONFIG
1592 Time to wait after FPGA configuration. The default is
1595 - Configuration Management:
1598 If defined, this string will be added to the U-Boot
1599 version information (U_BOOT_VERSION)
1601 - Vendor Parameter Protection:
1603 U-Boot considers the values of the environment
1604 variables "serial#" (Board Serial Number) and
1605 "ethaddr" (Ethernet Address) to be parameters that
1606 are set once by the board vendor / manufacturer, and
1607 protects these variables from casual modification by
1608 the user. Once set, these variables are read-only,
1609 and write or delete attempts are rejected. You can
1610 change this behaviour:
1612 If CONFIG_ENV_OVERWRITE is #defined in your config
1613 file, the write protection for vendor parameters is
1614 completely disabled. Anybody can change or delete
1617 Alternatively, if you #define _both_ CONFIG_ETHADDR
1618 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1619 Ethernet address is installed in the environment,
1620 which can be changed exactly ONCE by the user. [The
1621 serial# is unaffected by this, i. e. it remains
1627 Define this variable to enable the reservation of
1628 "protected RAM", i. e. RAM which is not overwritten
1629 by U-Boot. Define CONFIG_PRAM to hold the number of
1630 kB you want to reserve for pRAM. You can overwrite
1631 this default value by defining an environment
1632 variable "pram" to the number of kB you want to
1633 reserve. Note that the board info structure will
1634 still show the full amount of RAM. If pRAM is
1635 reserved, a new environment variable "mem" will
1636 automatically be defined to hold the amount of
1637 remaining RAM in a form that can be passed as boot
1638 argument to Linux, for instance like that:
1640 setenv bootargs ... mem=\${mem}
1643 This way you can tell Linux not to use this memory,
1644 either, which results in a memory region that will
1645 not be affected by reboots.
1647 *WARNING* If your board configuration uses automatic
1648 detection of the RAM size, you must make sure that
1649 this memory test is non-destructive. So far, the
1650 following board configurations are known to be
1653 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1654 HERMES, IP860, RPXlite, LWMON, LANTEC,
1655 PCU_E, FLAGADM, TQM8260
1660 Define this variable to stop the system in case of a
1661 fatal error, so that you have to reset it manually.
1662 This is probably NOT a good idea for an embedded
1663 system where you want the system to reboot
1664 automatically as fast as possible, but it may be
1665 useful during development since you can try to debug
1666 the conditions that lead to the situation.
1668 CONFIG_NET_RETRY_COUNT
1670 This variable defines the number of retries for
1671 network operations like ARP, RARP, TFTP, or BOOTP
1672 before giving up the operation. If not defined, a
1673 default value of 5 is used.
1677 Timeout waiting for an ARP reply in milliseconds.
1679 - Command Interpreter:
1680 CONFIG_AUTO_COMPLETE
1682 Enable auto completion of commands using TAB.
1684 Note that this feature has NOT been implemented yet
1685 for the "hush" shell.
1688 CONFIG_SYS_HUSH_PARSER
1690 Define this variable to enable the "hush" shell (from
1691 Busybox) as command line interpreter, thus enabling
1692 powerful command line syntax like
1693 if...then...else...fi conditionals or `&&' and '||'
1694 constructs ("shell scripts").
1696 If undefined, you get the old, much simpler behaviour
1697 with a somewhat smaller memory footprint.
1700 CONFIG_SYS_PROMPT_HUSH_PS2
1702 This defines the secondary prompt string, which is
1703 printed when the command interpreter needs more input
1704 to complete a command. Usually "> ".
1708 In the current implementation, the local variables
1709 space and global environment variables space are
1710 separated. Local variables are those you define by
1711 simply typing `name=value'. To access a local
1712 variable later on, you have write `$name' or
1713 `${name}'; to execute the contents of a variable
1714 directly type `$name' at the command prompt.
1716 Global environment variables are those you use
1717 setenv/printenv to work with. To run a command stored
1718 in such a variable, you need to use the run command,
1719 and you must not use the '$' sign to access them.
1721 To store commands and special characters in a
1722 variable, please use double quotation marks
1723 surrounding the whole text of the variable, instead
1724 of the backslashes before semicolons and special
1727 - Commandline Editing and History:
1728 CONFIG_CMDLINE_EDITING
1730 Enable editing and History functions for interactive
1731 commandline input operations
1733 - Default Environment:
1734 CONFIG_EXTRA_ENV_SETTINGS
1736 Define this to contain any number of null terminated
1737 strings (variable = value pairs) that will be part of
1738 the default environment compiled into the boot image.
1740 For example, place something like this in your
1741 board's config file:
1743 #define CONFIG_EXTRA_ENV_SETTINGS \
1747 Warning: This method is based on knowledge about the
1748 internal format how the environment is stored by the
1749 U-Boot code. This is NOT an official, exported
1750 interface! Although it is unlikely that this format
1751 will change soon, there is no guarantee either.
1752 You better know what you are doing here.
1754 Note: overly (ab)use of the default environment is
1755 discouraged. Make sure to check other ways to preset
1756 the environment like the autoscript function or the
1759 - DataFlash Support:
1760 CONFIG_HAS_DATAFLASH
1762 Defining this option enables DataFlash features and
1763 allows to read/write in Dataflash via the standard
1766 - SystemACE Support:
1769 Adding this option adds support for Xilinx SystemACE
1770 chips attached via some sort of local bus. The address
1771 of the chip must also be defined in the
1772 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1774 #define CONFIG_SYSTEMACE
1775 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1777 When SystemACE support is added, the "ace" device type
1778 becomes available to the fat commands, i.e. fatls.
1780 - TFTP Fixed UDP Port:
1783 If this is defined, the environment variable tftpsrcp
1784 is used to supply the TFTP UDP source port value.
1785 If tftpsrcp isn't defined, the normal pseudo-random port
1786 number generator is used.
1788 Also, the environment variable tftpdstp is used to supply
1789 the TFTP UDP destination port value. If tftpdstp isn't
1790 defined, the normal port 69 is used.
1792 The purpose for tftpsrcp is to allow a TFTP server to
1793 blindly start the TFTP transfer using the pre-configured
1794 target IP address and UDP port. This has the effect of
1795 "punching through" the (Windows XP) firewall, allowing
1796 the remainder of the TFTP transfer to proceed normally.
1797 A better solution is to properly configure the firewall,
1798 but sometimes that is not allowed.
1800 - Show boot progress:
1801 CONFIG_SHOW_BOOT_PROGRESS
1803 Defining this option allows to add some board-
1804 specific code (calling a user-provided function
1805 "show_boot_progress(int)") that enables you to show
1806 the system's boot progress on some display (for
1807 example, some LED's) on your board. At the moment,
1808 the following checkpoints are implemented:
1810 - Automatic software updates via TFTP server
1812 CONFIG_UPDATE_TFTP_CNT_MAX
1813 CONFIG_UPDATE_TFTP_MSEC_MAX
1815 These options enable and control the auto-update feature;
1816 for a more detailed description refer to doc/README.update.
1818 Legacy uImage format:
1821 1 common/cmd_bootm.c before attempting to boot an image
1822 -1 common/cmd_bootm.c Image header has bad magic number
1823 2 common/cmd_bootm.c Image header has correct magic number
1824 -2 common/cmd_bootm.c Image header has bad checksum
1825 3 common/cmd_bootm.c Image header has correct checksum
1826 -3 common/cmd_bootm.c Image data has bad checksum
1827 4 common/cmd_bootm.c Image data has correct checksum
1828 -4 common/cmd_bootm.c Image is for unsupported architecture
1829 5 common/cmd_bootm.c Architecture check OK
1830 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1831 6 common/cmd_bootm.c Image Type check OK
1832 -6 common/cmd_bootm.c gunzip uncompression error
1833 -7 common/cmd_bootm.c Unimplemented compression type
1834 7 common/cmd_bootm.c Uncompression OK
1835 8 common/cmd_bootm.c No uncompress/copy overwrite error
1836 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1838 9 common/image.c Start initial ramdisk verification
1839 -10 common/image.c Ramdisk header has bad magic number
1840 -11 common/image.c Ramdisk header has bad checksum
1841 10 common/image.c Ramdisk header is OK
1842 -12 common/image.c Ramdisk data has bad checksum
1843 11 common/image.c Ramdisk data has correct checksum
1844 12 common/image.c Ramdisk verification complete, start loading
1845 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1846 13 common/image.c Start multifile image verification
1847 14 common/image.c No initial ramdisk, no multifile, continue.
1849 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1851 -30 lib_ppc/board.c Fatal error, hang the system
1852 -31 post/post.c POST test failed, detected by post_output_backlog()
1853 -32 post/post.c POST test failed, detected by post_run_single()
1855 34 common/cmd_doc.c before loading a Image from a DOC device
1856 -35 common/cmd_doc.c Bad usage of "doc" command
1857 35 common/cmd_doc.c correct usage of "doc" command
1858 -36 common/cmd_doc.c No boot device
1859 36 common/cmd_doc.c correct boot device
1860 -37 common/cmd_doc.c Unknown Chip ID on boot device
1861 37 common/cmd_doc.c correct chip ID found, device available
1862 -38 common/cmd_doc.c Read Error on boot device
1863 38 common/cmd_doc.c reading Image header from DOC device OK
1864 -39 common/cmd_doc.c Image header has bad magic number
1865 39 common/cmd_doc.c Image header has correct magic number
1866 -40 common/cmd_doc.c Error reading Image from DOC device
1867 40 common/cmd_doc.c Image header has correct magic number
1868 41 common/cmd_ide.c before loading a Image from a IDE device
1869 -42 common/cmd_ide.c Bad usage of "ide" command
1870 42 common/cmd_ide.c correct usage of "ide" command
1871 -43 common/cmd_ide.c No boot device
1872 43 common/cmd_ide.c boot device found
1873 -44 common/cmd_ide.c Device not available
1874 44 common/cmd_ide.c Device available
1875 -45 common/cmd_ide.c wrong partition selected
1876 45 common/cmd_ide.c partition selected
1877 -46 common/cmd_ide.c Unknown partition table
1878 46 common/cmd_ide.c valid partition table found
1879 -47 common/cmd_ide.c Invalid partition type
1880 47 common/cmd_ide.c correct partition type
1881 -48 common/cmd_ide.c Error reading Image Header on boot device
1882 48 common/cmd_ide.c reading Image Header from IDE device OK
1883 -49 common/cmd_ide.c Image header has bad magic number
1884 49 common/cmd_ide.c Image header has correct magic number
1885 -50 common/cmd_ide.c Image header has bad checksum
1886 50 common/cmd_ide.c Image header has correct checksum
1887 -51 common/cmd_ide.c Error reading Image from IDE device
1888 51 common/cmd_ide.c reading Image from IDE device OK
1889 52 common/cmd_nand.c before loading a Image from a NAND device
1890 -53 common/cmd_nand.c Bad usage of "nand" command
1891 53 common/cmd_nand.c correct usage of "nand" command
1892 -54 common/cmd_nand.c No boot device
1893 54 common/cmd_nand.c boot device found
1894 -55 common/cmd_nand.c Unknown Chip ID on boot device
1895 55 common/cmd_nand.c correct chip ID found, device available
1896 -56 common/cmd_nand.c Error reading Image Header on boot device
1897 56 common/cmd_nand.c reading Image Header from NAND device OK
1898 -57 common/cmd_nand.c Image header has bad magic number
1899 57 common/cmd_nand.c Image header has correct magic number
1900 -58 common/cmd_nand.c Error reading Image from NAND device
1901 58 common/cmd_nand.c reading Image from NAND device OK
1903 -60 common/env_common.c Environment has a bad CRC, using default
1905 64 net/eth.c starting with Ethernet configuration.
1906 -64 net/eth.c no Ethernet found.
1907 65 net/eth.c Ethernet found.
1909 -80 common/cmd_net.c usage wrong
1910 80 common/cmd_net.c before calling NetLoop()
1911 -81 common/cmd_net.c some error in NetLoop() occurred
1912 81 common/cmd_net.c NetLoop() back without error
1913 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1914 82 common/cmd_net.c trying automatic boot
1915 83 common/cmd_net.c running autoscript
1916 -83 common/cmd_net.c some error in automatic boot or autoscript
1917 84 common/cmd_net.c end without errors
1922 100 common/cmd_bootm.c Kernel FIT Image has correct format
1923 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1924 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1925 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1926 102 common/cmd_bootm.c Kernel unit name specified
1927 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1928 103 common/cmd_bootm.c Found configuration node
1929 104 common/cmd_bootm.c Got kernel subimage node offset
1930 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1931 105 common/cmd_bootm.c Kernel subimage hash verification OK
1932 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1933 106 common/cmd_bootm.c Architecture check OK
1934 -106 common/cmd_bootm.c Kernel subimage has wrong type
1935 107 common/cmd_bootm.c Kernel subimage type OK
1936 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1937 108 common/cmd_bootm.c Got kernel subimage data/size
1938 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1939 -109 common/cmd_bootm.c Can't get kernel subimage type
1940 -110 common/cmd_bootm.c Can't get kernel subimage comp
1941 -111 common/cmd_bootm.c Can't get kernel subimage os
1942 -112 common/cmd_bootm.c Can't get kernel subimage load address
1943 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1945 120 common/image.c Start initial ramdisk verification
1946 -120 common/image.c Ramdisk FIT image has incorrect format
1947 121 common/image.c Ramdisk FIT image has correct format
1948 122 common/image.c No ramdisk subimage unit name, using configuration
1949 -122 common/image.c Can't get configuration for ramdisk subimage
1950 123 common/image.c Ramdisk unit name specified
1951 -124 common/image.c Can't get ramdisk subimage node offset
1952 125 common/image.c Got ramdisk subimage node offset
1953 -125 common/image.c Ramdisk subimage hash verification failed
1954 126 common/image.c Ramdisk subimage hash verification OK
1955 -126 common/image.c Ramdisk subimage for unsupported architecture
1956 127 common/image.c Architecture check OK
1957 -127 common/image.c Can't get ramdisk subimage data/size
1958 128 common/image.c Got ramdisk subimage data/size
1959 129 common/image.c Can't get ramdisk load address
1960 -129 common/image.c Got ramdisk load address
1962 -130 common/cmd_doc.c Incorrect FIT image format
1963 131 common/cmd_doc.c FIT image format OK
1965 -140 common/cmd_ide.c Incorrect FIT image format
1966 141 common/cmd_ide.c FIT image format OK
1968 -150 common/cmd_nand.c Incorrect FIT image format
1969 151 common/cmd_nand.c FIT image format OK
1975 [so far only for SMDK2400 and TRAB boards]
1977 - Modem support enable:
1978 CONFIG_MODEM_SUPPORT
1980 - RTS/CTS Flow control enable:
1983 - Modem debug support:
1984 CONFIG_MODEM_SUPPORT_DEBUG
1986 Enables debugging stuff (char screen[1024], dbg())
1987 for modem support. Useful only with BDI2000.
1989 - Interrupt support (PPC):
1991 There are common interrupt_init() and timer_interrupt()
1992 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1993 for CPU specific initialization. interrupt_init_cpu()
1994 should set decrementer_count to appropriate value. If
1995 CPU resets decrementer automatically after interrupt
1996 (ppc4xx) it should set decrementer_count to zero.
1997 timer_interrupt() calls timer_interrupt_cpu() for CPU
1998 specific handling. If board has watchdog / status_led
1999 / other_activity_monitor it works automatically from
2000 general timer_interrupt().
2004 In the target system modem support is enabled when a
2005 specific key (key combination) is pressed during
2006 power-on. Otherwise U-Boot will boot normally
2007 (autoboot). The key_pressed() function is called from
2008 board_init(). Currently key_pressed() is a dummy
2009 function, returning 1 and thus enabling modem
2012 If there are no modem init strings in the
2013 environment, U-Boot proceed to autoboot; the
2014 previous output (banner, info printfs) will be
2017 See also: doc/README.Modem
2020 Configuration Settings:
2021 -----------------------
2023 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2024 undefine this when you're short of memory.
2026 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2027 prompt for user input.
2029 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2031 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2033 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2035 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2036 the application (usually a Linux kernel) when it is
2039 - CONFIG_SYS_BAUDRATE_TABLE:
2040 List of legal baudrate settings for this board.
2042 - CONFIG_SYS_CONSOLE_INFO_QUIET
2043 Suppress display of console information at boot.
2045 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2046 If the board specific function
2047 extern int overwrite_console (void);
2048 returns 1, the stdin, stderr and stdout are switched to the
2049 serial port, else the settings in the environment are used.
2051 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2052 Enable the call to overwrite_console().
2054 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2055 Enable overwrite of previous console environment settings.
2057 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2058 Begin and End addresses of the area used by the
2061 - CONFIG_SYS_ALT_MEMTEST:
2062 Enable an alternate, more extensive memory test.
2064 - CONFIG_SYS_MEMTEST_SCRATCH:
2065 Scratch address used by the alternate memory test
2066 You only need to set this if address zero isn't writeable
2068 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2069 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2070 this specified memory area will get subtracted from the top
2071 (end) of RAM and won't get "touched" at all by U-Boot. By
2072 fixing up gd->ram_size the Linux kernel should gets passed
2073 the now "corrected" memory size and won't touch it either.
2074 This should work for arch/ppc and arch/powerpc. Only Linux
2075 board ports in arch/powerpc with bootwrapper support that
2076 recalculate the memory size from the SDRAM controller setup
2077 will have to get fixed in Linux additionally.
2079 This option can be used as a workaround for the 440EPx/GRx
2080 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2083 WARNING: Please make sure that this value is a multiple of
2084 the Linux page size (normally 4k). If this is not the case,
2085 then the end address of the Linux memory will be located at a
2086 non page size aligned address and this could cause major
2089 - CONFIG_SYS_TFTP_LOADADDR:
2090 Default load address for network file downloads
2092 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2093 Enable temporary baudrate change while serial download
2095 - CONFIG_SYS_SDRAM_BASE:
2096 Physical start address of SDRAM. _Must_ be 0 here.
2098 - CONFIG_SYS_MBIO_BASE:
2099 Physical start address of Motherboard I/O (if using a
2102 - CONFIG_SYS_FLASH_BASE:
2103 Physical start address of Flash memory.
2105 - CONFIG_SYS_MONITOR_BASE:
2106 Physical start address of boot monitor code (set by
2107 make config files to be same as the text base address
2108 (TEXT_BASE) used when linking) - same as
2109 CONFIG_SYS_FLASH_BASE when booting from flash.
2111 - CONFIG_SYS_MONITOR_LEN:
2112 Size of memory reserved for monitor code, used to
2113 determine _at_compile_time_ (!) if the environment is
2114 embedded within the U-Boot image, or in a separate
2117 - CONFIG_SYS_MALLOC_LEN:
2118 Size of DRAM reserved for malloc() use.
2120 - CONFIG_SYS_BOOTM_LEN:
2121 Normally compressed uImages are limited to an
2122 uncompressed size of 8 MBytes. If this is not enough,
2123 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2124 to adjust this setting to your needs.
2126 - CONFIG_SYS_BOOTMAPSZ:
2127 Maximum size of memory mapped by the startup code of
2128 the Linux kernel; all data that must be processed by
2129 the Linux kernel (bd_info, boot arguments, FDT blob if
2130 used) must be put below this limit, unless "bootm_low"
2131 enviroment variable is defined and non-zero. In such case
2132 all data for the Linux kernel must be between "bootm_low"
2133 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2135 - CONFIG_SYS_MAX_FLASH_BANKS:
2136 Max number of Flash memory banks
2138 - CONFIG_SYS_MAX_FLASH_SECT:
2139 Max number of sectors on a Flash chip
2141 - CONFIG_SYS_FLASH_ERASE_TOUT:
2142 Timeout for Flash erase operations (in ms)
2144 - CONFIG_SYS_FLASH_WRITE_TOUT:
2145 Timeout for Flash write operations (in ms)
2147 - CONFIG_SYS_FLASH_LOCK_TOUT
2148 Timeout for Flash set sector lock bit operation (in ms)
2150 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2151 Timeout for Flash clear lock bits operation (in ms)
2153 - CONFIG_SYS_FLASH_PROTECTION
2154 If defined, hardware flash sectors protection is used
2155 instead of U-Boot software protection.
2157 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2159 Enable TFTP transfers directly to flash memory;
2160 without this option such a download has to be
2161 performed in two steps: (1) download to RAM, and (2)
2162 copy from RAM to flash.
2164 The two-step approach is usually more reliable, since
2165 you can check if the download worked before you erase
2166 the flash, but in some situations (when system RAM is
2167 too limited to allow for a temporary copy of the
2168 downloaded image) this option may be very useful.
2170 - CONFIG_SYS_FLASH_CFI:
2171 Define if the flash driver uses extra elements in the
2172 common flash structure for storing flash geometry.
2174 - CONFIG_FLASH_CFI_DRIVER
2175 This option also enables the building of the cfi_flash driver
2176 in the drivers directory
2178 - CONFIG_FLASH_CFI_MTD
2179 This option enables the building of the cfi_mtd driver
2180 in the drivers directory. The driver exports CFI flash
2183 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2184 Use buffered writes to flash.
2186 - CONFIG_FLASH_SPANSION_S29WS_N
2187 s29ws-n MirrorBit flash has non-standard addresses for buffered
2190 - CONFIG_SYS_FLASH_QUIET_TEST
2191 If this option is defined, the common CFI flash doesn't
2192 print it's warning upon not recognized FLASH banks. This
2193 is useful, if some of the configured banks are only
2194 optionally available.
2196 - CONFIG_FLASH_SHOW_PROGRESS
2197 If defined (must be an integer), print out countdown
2198 digits and dots. Recommended value: 45 (9..1) for 80
2199 column displays, 15 (3..1) for 40 column displays.
2201 - CONFIG_SYS_RX_ETH_BUFFER:
2202 Defines the number of Ethernet receive buffers. On some
2203 Ethernet controllers it is recommended to set this value
2204 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2205 buffers can be full shortly after enabling the interface
2206 on high Ethernet traffic.
2207 Defaults to 4 if not defined.
2209 The following definitions that deal with the placement and management
2210 of environment data (variable area); in general, we support the
2211 following configurations:
2213 - CONFIG_ENV_IS_IN_FLASH:
2215 Define this if the environment is in flash memory.
2217 a) The environment occupies one whole flash sector, which is
2218 "embedded" in the text segment with the U-Boot code. This
2219 happens usually with "bottom boot sector" or "top boot
2220 sector" type flash chips, which have several smaller
2221 sectors at the start or the end. For instance, such a
2222 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2223 such a case you would place the environment in one of the
2224 4 kB sectors - with U-Boot code before and after it. With
2225 "top boot sector" type flash chips, you would put the
2226 environment in one of the last sectors, leaving a gap
2227 between U-Boot and the environment.
2229 - CONFIG_ENV_OFFSET:
2231 Offset of environment data (variable area) to the
2232 beginning of flash memory; for instance, with bottom boot
2233 type flash chips the second sector can be used: the offset
2234 for this sector is given here.
2236 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2240 This is just another way to specify the start address of
2241 the flash sector containing the environment (instead of
2244 - CONFIG_ENV_SECT_SIZE:
2246 Size of the sector containing the environment.
2249 b) Sometimes flash chips have few, equal sized, BIG sectors.
2250 In such a case you don't want to spend a whole sector for
2255 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2256 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2257 of this flash sector for the environment. This saves
2258 memory for the RAM copy of the environment.
2260 It may also save flash memory if you decide to use this
2261 when your environment is "embedded" within U-Boot code,
2262 since then the remainder of the flash sector could be used
2263 for U-Boot code. It should be pointed out that this is
2264 STRONGLY DISCOURAGED from a robustness point of view:
2265 updating the environment in flash makes it always
2266 necessary to erase the WHOLE sector. If something goes
2267 wrong before the contents has been restored from a copy in
2268 RAM, your target system will be dead.
2270 - CONFIG_ENV_ADDR_REDUND
2271 CONFIG_ENV_SIZE_REDUND
2273 These settings describe a second storage area used to hold
2274 a redundant copy of the environment data, so that there is
2275 a valid backup copy in case there is a power failure during
2276 a "saveenv" operation.
2278 BE CAREFUL! Any changes to the flash layout, and some changes to the
2279 source code will make it necessary to adapt <board>/u-boot.lds*
2283 - CONFIG_ENV_IS_IN_NVRAM:
2285 Define this if you have some non-volatile memory device
2286 (NVRAM, battery buffered SRAM) which you want to use for the
2292 These two #defines are used to determine the memory area you
2293 want to use for environment. It is assumed that this memory
2294 can just be read and written to, without any special
2297 BE CAREFUL! The first access to the environment happens quite early
2298 in U-Boot initalization (when we try to get the setting of for the
2299 console baudrate). You *MUST* have mapped your NVRAM area then, or
2302 Please note that even with NVRAM we still use a copy of the
2303 environment in RAM: we could work on NVRAM directly, but we want to
2304 keep settings there always unmodified except somebody uses "saveenv"
2305 to save the current settings.
2308 - CONFIG_ENV_IS_IN_EEPROM:
2310 Use this if you have an EEPROM or similar serial access
2311 device and a driver for it.
2313 - CONFIG_ENV_OFFSET:
2316 These two #defines specify the offset and size of the
2317 environment area within the total memory of your EEPROM.
2319 - CONFIG_SYS_I2C_EEPROM_ADDR:
2320 If defined, specified the chip address of the EEPROM device.
2321 The default address is zero.
2323 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2324 If defined, the number of bits used to address bytes in a
2325 single page in the EEPROM device. A 64 byte page, for example
2326 would require six bits.
2328 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2329 If defined, the number of milliseconds to delay between
2330 page writes. The default is zero milliseconds.
2332 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2333 The length in bytes of the EEPROM memory array address. Note
2334 that this is NOT the chip address length!
2336 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2337 EEPROM chips that implement "address overflow" are ones
2338 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2339 address and the extra bits end up in the "chip address" bit
2340 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2343 Note that we consider the length of the address field to
2344 still be one byte because the extra address bits are hidden
2345 in the chip address.
2347 - CONFIG_SYS_EEPROM_SIZE:
2348 The size in bytes of the EEPROM device.
2351 - CONFIG_ENV_IS_IN_DATAFLASH:
2353 Define this if you have a DataFlash memory device which you
2354 want to use for the environment.
2356 - CONFIG_ENV_OFFSET:
2360 These three #defines specify the offset and size of the
2361 environment area within the total memory of your DataFlash placed
2362 at the specified address.
2364 - CONFIG_ENV_IS_IN_NAND:
2366 Define this if you have a NAND device which you want to use
2367 for the environment.
2369 - CONFIG_ENV_OFFSET:
2372 These two #defines specify the offset and size of the environment
2373 area within the first NAND device.
2375 - CONFIG_ENV_OFFSET_REDUND
2377 This setting describes a second storage area of CONFIG_ENV_SIZE
2378 size used to hold a redundant copy of the environment data,
2379 so that there is a valid backup copy in case there is a
2380 power failure during a "saveenv" operation.
2382 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2383 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2384 the NAND devices block size.
2386 - CONFIG_SYS_SPI_INIT_OFFSET
2388 Defines offset to the initial SPI buffer area in DPRAM. The
2389 area is used at an early stage (ROM part) if the environment
2390 is configured to reside in the SPI EEPROM: We need a 520 byte
2391 scratch DPRAM area. It is used between the two initialization
2392 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2393 to be a good choice since it makes it far enough from the
2394 start of the data area as well as from the stack pointer.
2396 Please note that the environment is read-only until the monitor
2397 has been relocated to RAM and a RAM copy of the environment has been
2398 created; also, when using EEPROM you will have to use getenv_r()
2399 until then to read environment variables.
2401 The environment is protected by a CRC32 checksum. Before the monitor
2402 is relocated into RAM, as a result of a bad CRC you will be working
2403 with the compiled-in default environment - *silently*!!! [This is
2404 necessary, because the first environment variable we need is the
2405 "baudrate" setting for the console - if we have a bad CRC, we don't
2406 have any device yet where we could complain.]
2408 Note: once the monitor has been relocated, then it will complain if
2409 the default environment is used; a new CRC is computed as soon as you
2410 use the "saveenv" command to store a valid environment.
2412 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2413 Echo the inverted Ethernet link state to the fault LED.
2415 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2416 also needs to be defined.
2418 - CONFIG_SYS_FAULT_MII_ADDR:
2419 MII address of the PHY to check for the Ethernet link state.
2421 - CONFIG_SYS_64BIT_VSPRINTF:
2422 Makes vsprintf (and all *printf functions) support printing
2423 of 64bit values by using the L quantifier
2425 - CONFIG_SYS_64BIT_STRTOUL:
2426 Adds simple_strtoull that returns a 64bit value
2428 Low Level (hardware related) configuration options:
2429 ---------------------------------------------------
2431 - CONFIG_SYS_CACHELINE_SIZE:
2432 Cache Line Size of the CPU.
2434 - CONFIG_SYS_DEFAULT_IMMR:
2435 Default address of the IMMR after system reset.
2437 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2438 and RPXsuper) to be able to adjust the position of
2439 the IMMR register after a reset.
2441 - Floppy Disk Support:
2442 CONFIG_SYS_FDC_DRIVE_NUMBER
2444 the default drive number (default value 0)
2446 CONFIG_SYS_ISA_IO_STRIDE
2448 defines the spacing between FDC chipset registers
2451 CONFIG_SYS_ISA_IO_OFFSET
2453 defines the offset of register from address. It
2454 depends on which part of the data bus is connected to
2455 the FDC chipset. (default value 0)
2457 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2458 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2461 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2462 fdc_hw_init() is called at the beginning of the FDC
2463 setup. fdc_hw_init() must be provided by the board
2464 source code. It is used to make hardware dependant
2467 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2468 DO NOT CHANGE unless you know exactly what you're
2469 doing! (11-4) [MPC8xx/82xx systems only]
2471 - CONFIG_SYS_INIT_RAM_ADDR:
2473 Start address of memory area that can be used for
2474 initial data and stack; please note that this must be
2475 writable memory that is working WITHOUT special
2476 initialization, i. e. you CANNOT use normal RAM which
2477 will become available only after programming the
2478 memory controller and running certain initialization
2481 U-Boot uses the following memory types:
2482 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2483 - MPC824X: data cache
2484 - PPC4xx: data cache
2486 - CONFIG_SYS_GBL_DATA_OFFSET:
2488 Offset of the initial data structure in the memory
2489 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2490 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2491 data is located at the end of the available space
2492 (sometimes written as (CONFIG_SYS_INIT_RAM_END -
2493 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2494 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2495 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2498 On the MPC824X (or other systems that use the data
2499 cache for initial memory) the address chosen for
2500 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2501 point to an otherwise UNUSED address space between
2502 the top of RAM and the start of the PCI space.
2504 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2506 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2508 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2510 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2512 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2514 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2516 - CONFIG_SYS_OR_TIMING_SDRAM:
2519 - CONFIG_SYS_MAMR_PTA:
2520 periodic timer for refresh
2522 - CONFIG_SYS_DER: Debug Event Register (37-47)
2524 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2525 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2526 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2527 CONFIG_SYS_BR1_PRELIM:
2528 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2530 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2531 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2532 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2533 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2535 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2536 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2537 Machine Mode Register and Memory Periodic Timer
2538 Prescaler definitions (SDRAM timing)
2540 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2541 enable I2C microcode relocation patch (MPC8xx);
2542 define relocation offset in DPRAM [DSP2]
2544 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2545 enable SMC microcode relocation patch (MPC8xx);
2546 define relocation offset in DPRAM [SMC1]
2548 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2549 enable SPI microcode relocation patch (MPC8xx);
2550 define relocation offset in DPRAM [SCC4]
2552 - CONFIG_SYS_USE_OSCCLK:
2553 Use OSCM clock mode on MBX8xx board. Be careful,
2554 wrong setting might damage your board. Read
2555 doc/README.MBX before setting this variable!
2557 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2558 Offset of the bootmode word in DPRAM used by post
2559 (Power On Self Tests). This definition overrides
2560 #define'd default value in commproc.h resp.
2563 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2564 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2565 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2566 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2567 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2568 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2569 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2570 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2571 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2574 Get DDR timing information from an I2C EEPROM. Common
2575 with pluggable memory modules such as SODIMMs
2578 I2C address of the SPD EEPROM
2580 - CONFIG_SYS_SPD_BUS_NUM
2581 If SPD EEPROM is on an I2C bus other than the first
2582 one, specify here. Note that the value must resolve
2583 to something your driver can deal with.
2585 - CONFIG_SYS_83XX_DDR_USES_CS0
2586 Only for 83xx systems. If specified, then DDR should
2587 be configured using CS0 and CS1 instead of CS2 and CS3.
2589 - CONFIG_SYS_83XX_DDR_USES_CS0
2590 Only for 83xx systems. If specified, then DDR should
2591 be configured using CS0 and CS1 instead of CS2 and CS3.
2593 - CONFIG_ETHER_ON_FEC[12]
2594 Define to enable FEC[12] on a 8xx series processor.
2596 - CONFIG_FEC[12]_PHY
2597 Define to the hardcoded PHY address which corresponds
2598 to the given FEC; i. e.
2599 #define CONFIG_FEC1_PHY 4
2600 means that the PHY with address 4 is connected to FEC1
2602 When set to -1, means to probe for first available.
2604 - CONFIG_FEC[12]_PHY_NORXERR
2605 The PHY does not have a RXERR line (RMII only).
2606 (so program the FEC to ignore it).
2609 Enable RMII mode for all FECs.
2610 Note that this is a global option, we can't
2611 have one FEC in standard MII mode and another in RMII mode.
2613 - CONFIG_CRC32_VERIFY
2614 Add a verify option to the crc32 command.
2617 => crc32 -v <address> <count> <crc32>
2619 Where address/count indicate a memory area
2620 and crc32 is the correct crc32 which the
2624 Add the "loopw" memory command. This only takes effect if
2625 the memory commands are activated globally (CONFIG_CMD_MEM).
2628 Add the "mdc" and "mwc" memory commands. These are cyclic
2633 This command will print 4 bytes (10,11,12,13) each 500 ms.
2635 => mwc.l 100 12345678 10
2636 This command will write 12345678 to address 100 all 10 ms.
2638 This only takes effect if the memory commands are activated
2639 globally (CONFIG_CMD_MEM).
2641 - CONFIG_SKIP_LOWLEVEL_INIT
2642 - CONFIG_SKIP_RELOCATE_UBOOT
2644 [ARM only] If these variables are defined, then
2645 certain low level initializations (like setting up
2646 the memory controller) are omitted and/or U-Boot does
2647 not relocate itself into RAM.
2648 Normally these variables MUST NOT be defined. The
2649 only exception is when U-Boot is loaded (to RAM) by
2650 some other boot loader or by a debugger which
2651 performs these initializations itself.
2654 Building the Software:
2655 ======================
2657 Building U-Boot has been tested in several native build environments
2658 and in many different cross environments. Of course we cannot support
2659 all possibly existing versions of cross development tools in all
2660 (potentially obsolete) versions. In case of tool chain problems we
2661 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2662 which is extensively used to build and test U-Boot.
2664 If you are not using a native environment, it is assumed that you
2665 have GNU cross compiling tools available in your path. In this case,
2666 you must set the environment variable CROSS_COMPILE in your shell.
2667 Note that no changes to the Makefile or any other source files are
2668 necessary. For example using the ELDK on a 4xx CPU, please enter:
2670 $ CROSS_COMPILE=ppc_4xx-
2671 $ export CROSS_COMPILE
2673 U-Boot is intended to be simple to build. After installing the
2674 sources you must configure U-Boot for one specific board type. This
2679 where "NAME_config" is the name of one of the existing configu-
2680 rations; see the main Makefile for supported names.
2682 Note: for some board special configuration names may exist; check if
2683 additional information is available from the board vendor; for
2684 instance, the TQM823L systems are available without (standard)
2685 or with LCD support. You can select such additional "features"
2686 when choosing the configuration, i. e.
2689 - will configure for a plain TQM823L, i. e. no LCD support
2691 make TQM823L_LCD_config
2692 - will configure for a TQM823L with U-Boot console on LCD
2697 Finally, type "make all", and you should get some working U-Boot
2698 images ready for download to / installation on your system:
2700 - "u-boot.bin" is a raw binary image
2701 - "u-boot" is an image in ELF binary format
2702 - "u-boot.srec" is in Motorola S-Record format
2704 By default the build is performed locally and the objects are saved
2705 in the source directory. One of the two methods can be used to change
2706 this behavior and build U-Boot to some external directory:
2708 1. Add O= to the make command line invocations:
2710 make O=/tmp/build distclean
2711 make O=/tmp/build NAME_config
2712 make O=/tmp/build all
2714 2. Set environment variable BUILD_DIR to point to the desired location:
2716 export BUILD_DIR=/tmp/build
2721 Note that the command line "O=" setting overrides the BUILD_DIR environment
2725 Please be aware that the Makefiles assume you are using GNU make, so
2726 for instance on NetBSD you might need to use "gmake" instead of
2730 If the system board that you have is not listed, then you will need
2731 to port U-Boot to your hardware platform. To do this, follow these
2734 1. Add a new configuration option for your board to the toplevel
2735 "Makefile" and to the "MAKEALL" script, using the existing
2736 entries as examples. Note that here and at many other places
2737 boards and other names are listed in alphabetical sort order. Please
2739 2. Create a new directory to hold your board specific code. Add any
2740 files you need. In your board directory, you will need at least
2741 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2742 3. Create a new configuration file "include/configs/<board>.h" for
2744 3. If you're porting U-Boot to a new CPU, then also create a new
2745 directory to hold your CPU specific code. Add any files you need.
2746 4. Run "make <board>_config" with your new name.
2747 5. Type "make", and you should get a working "u-boot.srec" file
2748 to be installed on your target system.
2749 6. Debug and solve any problems that might arise.
2750 [Of course, this last step is much harder than it sounds.]
2753 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2754 ==============================================================
2756 If you have modified U-Boot sources (for instance added a new board
2757 or support for new devices, a new CPU, etc.) you are expected to
2758 provide feedback to the other developers. The feedback normally takes
2759 the form of a "patch", i. e. a context diff against a certain (latest
2760 official or latest in the git repository) version of U-Boot sources.
2762 But before you submit such a patch, please verify that your modifi-
2763 cation did not break existing code. At least make sure that *ALL* of
2764 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2765 just run the "MAKEALL" script, which will configure and build U-Boot
2766 for ALL supported system. Be warned, this will take a while. You can
2767 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2768 environment variable to the script, i. e. to use the ELDK cross tools
2771 CROSS_COMPILE=ppc_8xx- MAKEALL
2773 or to build on a native PowerPC system you can type
2775 CROSS_COMPILE=' ' MAKEALL
2777 When using the MAKEALL script, the default behaviour is to build
2778 U-Boot in the source directory. This location can be changed by
2779 setting the BUILD_DIR environment variable. Also, for each target
2780 built, the MAKEALL script saves two log files (<target>.ERR and
2781 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2782 location can be changed by setting the MAKEALL_LOGDIR environment
2783 variable. For example:
2785 export BUILD_DIR=/tmp/build
2786 export MAKEALL_LOGDIR=/tmp/log
2787 CROSS_COMPILE=ppc_8xx- MAKEALL
2789 With the above settings build objects are saved in the /tmp/build,
2790 log files are saved in the /tmp/log and the source tree remains clean
2791 during the whole build process.
2794 See also "U-Boot Porting Guide" below.
2797 Monitor Commands - Overview:
2798 ============================
2800 go - start application at address 'addr'
2801 run - run commands in an environment variable
2802 bootm - boot application image from memory
2803 bootp - boot image via network using BootP/TFTP protocol
2804 tftpboot- boot image via network using TFTP protocol
2805 and env variables "ipaddr" and "serverip"
2806 (and eventually "gatewayip")
2807 rarpboot- boot image via network using RARP/TFTP protocol
2808 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2809 loads - load S-Record file over serial line
2810 loadb - load binary file over serial line (kermit mode)
2812 mm - memory modify (auto-incrementing)
2813 nm - memory modify (constant address)
2814 mw - memory write (fill)
2816 cmp - memory compare
2817 crc32 - checksum calculation
2818 imd - i2c memory display
2819 imm - i2c memory modify (auto-incrementing)
2820 inm - i2c memory modify (constant address)
2821 imw - i2c memory write (fill)
2822 icrc32 - i2c checksum calculation
2823 iprobe - probe to discover valid I2C chip addresses
2824 iloop - infinite loop on address range
2825 isdram - print SDRAM configuration information
2826 sspi - SPI utility commands
2827 base - print or set address offset
2828 printenv- print environment variables
2829 setenv - set environment variables
2830 saveenv - save environment variables to persistent storage
2831 protect - enable or disable FLASH write protection
2832 erase - erase FLASH memory
2833 flinfo - print FLASH memory information
2834 bdinfo - print Board Info structure
2835 iminfo - print header information for application image
2836 coninfo - print console devices and informations
2837 ide - IDE sub-system
2838 loop - infinite loop on address range
2839 loopw - infinite write loop on address range
2840 mtest - simple RAM test
2841 icache - enable or disable instruction cache
2842 dcache - enable or disable data cache
2843 reset - Perform RESET of the CPU
2844 echo - echo args to console
2845 version - print monitor version
2846 help - print online help
2847 ? - alias for 'help'
2850 Monitor Commands - Detailed Description:
2851 ========================================
2855 For now: just type "help <command>".
2858 Environment Variables:
2859 ======================
2861 U-Boot supports user configuration using Environment Variables which
2862 can be made persistent by saving to Flash memory.
2864 Environment Variables are set using "setenv", printed using
2865 "printenv", and saved to Flash using "saveenv". Using "setenv"
2866 without a value can be used to delete a variable from the
2867 environment. As long as you don't save the environment you are
2868 working with an in-memory copy. In case the Flash area containing the
2869 environment is erased by accident, a default environment is provided.
2871 Some configuration options can be set using Environment Variables:
2873 baudrate - see CONFIG_BAUDRATE
2875 bootdelay - see CONFIG_BOOTDELAY
2877 bootcmd - see CONFIG_BOOTCOMMAND
2879 bootargs - Boot arguments when booting an RTOS image
2881 bootfile - Name of the image to load with TFTP
2883 bootm_low - Memory range available for image processing in the bootm
2884 command can be restricted. This variable is given as
2885 a hexadecimal number and defines lowest address allowed
2886 for use by the bootm command. See also "bootm_size"
2887 environment variable. Address defined by "bootm_low" is
2888 also the base of the initial memory mapping for the Linux
2889 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
2891 bootm_size - Memory range available for image processing in the bootm
2892 command can be restricted. This variable is given as
2893 a hexadecimal number and defines the size of the region
2894 allowed for use by the bootm command. See also "bootm_low"
2895 environment variable.
2897 updatefile - Location of the software update file on a TFTP server, used
2898 by the automatic software update feature. Please refer to
2899 documentation in doc/README.update for more details.
2901 autoload - if set to "no" (any string beginning with 'n'),
2902 "bootp" will just load perform a lookup of the
2903 configuration from the BOOTP server, but not try to
2904 load any image using TFTP
2906 autoscript - if set to "yes" commands like "loadb", "loady",
2907 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2908 to automatically run script images (by internally
2909 calling "autoscript").
2911 autoscript_uname - if script image is in a format (FIT) this
2912 variable is used to get script subimage unit name.
2914 autostart - if set to "yes", an image loaded using the "bootp",
2915 "rarpboot", "tftpboot" or "diskboot" commands will
2916 be automatically started (by internally calling
2919 If set to "no", a standalone image passed to the
2920 "bootm" command will be copied to the load address
2921 (and eventually uncompressed), but NOT be started.
2922 This can be used to load and uncompress arbitrary
2925 i2cfast - (PPC405GP|PPC405EP only)
2926 if set to 'y' configures Linux I2C driver for fast
2927 mode (400kHZ). This environment variable is used in
2928 initialization code. So, for changes to be effective
2929 it must be saved and board must be reset.
2931 initrd_high - restrict positioning of initrd images:
2932 If this variable is not set, initrd images will be
2933 copied to the highest possible address in RAM; this
2934 is usually what you want since it allows for
2935 maximum initrd size. If for some reason you want to
2936 make sure that the initrd image is loaded below the
2937 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
2938 variable to a value of "no" or "off" or "0".
2939 Alternatively, you can set it to a maximum upper
2940 address to use (U-Boot will still check that it
2941 does not overwrite the U-Boot stack and data).
2943 For instance, when you have a system with 16 MB
2944 RAM, and want to reserve 4 MB from use by Linux,
2945 you can do this by adding "mem=12M" to the value of
2946 the "bootargs" variable. However, now you must make
2947 sure that the initrd image is placed in the first
2948 12 MB as well - this can be done with
2950 setenv initrd_high 00c00000
2952 If you set initrd_high to 0xFFFFFFFF, this is an
2953 indication to U-Boot that all addresses are legal
2954 for the Linux kernel, including addresses in flash
2955 memory. In this case U-Boot will NOT COPY the
2956 ramdisk at all. This may be useful to reduce the
2957 boot time on your system, but requires that this
2958 feature is supported by your Linux kernel.
2960 ipaddr - IP address; needed for tftpboot command
2962 loadaddr - Default load address for commands like "bootp",
2963 "rarpboot", "tftpboot", "loadb" or "diskboot"
2965 loads_echo - see CONFIG_LOADS_ECHO
2967 serverip - TFTP server IP address; needed for tftpboot command
2969 bootretry - see CONFIG_BOOT_RETRY_TIME
2971 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2973 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2975 ethprime - When CONFIG_NET_MULTI is enabled controls which
2976 interface is used first.
2978 ethact - When CONFIG_NET_MULTI is enabled controls which
2979 interface is currently active. For example you
2980 can do the following
2982 => setenv ethact FEC ETHERNET
2983 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2984 => setenv ethact SCC ETHERNET
2985 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2987 ethrotate - When set to "no" U-Boot does not go through all
2988 available network interfaces.
2989 It just stays at the currently selected interface.
2991 netretry - When set to "no" each network operation will
2992 either succeed or fail without retrying.
2993 When set to "once" the network operation will
2994 fail when all the available network interfaces
2995 are tried once without success.
2996 Useful on scripts which control the retry operation
2999 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
3000 if set load address for the NPE microcode
3002 tftpsrcport - If this is set, the value is used for TFTP's
3005 tftpdstport - If this is set, the value is used for TFTP's UDP
3006 destination port instead of the Well Know Port 69.
3008 vlan - When set to a value < 4095 the traffic over
3009 Ethernet is encapsulated/received over 802.1q
3012 The following environment variables may be used and automatically
3013 updated by the network boot commands ("bootp" and "rarpboot"),
3014 depending the information provided by your boot server:
3016 bootfile - see above
3017 dnsip - IP address of your Domain Name Server
3018 dnsip2 - IP address of your secondary Domain Name Server
3019 gatewayip - IP address of the Gateway (Router) to use
3020 hostname - Target hostname
3022 netmask - Subnet Mask
3023 rootpath - Pathname of the root filesystem on the NFS server
3024 serverip - see above
3027 There are two special Environment Variables:
3029 serial# - contains hardware identification information such
3030 as type string and/or serial number
3031 ethaddr - Ethernet address
3033 These variables can be set only once (usually during manufacturing of
3034 the board). U-Boot refuses to delete or overwrite these variables
3035 once they have been set once.
3038 Further special Environment Variables:
3040 ver - Contains the U-Boot version string as printed
3041 with the "version" command. This variable is
3042 readonly (see CONFIG_VERSION_VARIABLE).
3045 Please note that changes to some configuration parameters may take
3046 only effect after the next boot (yes, that's just like Windoze :-).
3049 Command Line Parsing:
3050 =====================
3052 There are two different command line parsers available with U-Boot:
3053 the old "simple" one, and the much more powerful "hush" shell:
3055 Old, simple command line parser:
3056 --------------------------------
3058 - supports environment variables (through setenv / saveenv commands)
3059 - several commands on one line, separated by ';'
3060 - variable substitution using "... ${name} ..." syntax
3061 - special characters ('$', ';') can be escaped by prefixing with '\',
3063 setenv bootcmd bootm \${address}
3064 - You can also escape text by enclosing in single apostrophes, for example:
3065 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3070 - similar to Bourne shell, with control structures like
3071 if...then...else...fi, for...do...done; while...do...done,
3072 until...do...done, ...
3073 - supports environment ("global") variables (through setenv / saveenv
3074 commands) and local shell variables (through standard shell syntax
3075 "name=value"); only environment variables can be used with "run"
3081 (1) If a command line (or an environment variable executed by a "run"
3082 command) contains several commands separated by semicolon, and
3083 one of these commands fails, then the remaining commands will be
3086 (2) If you execute several variables with one call to run (i. e.
3087 calling run with a list of variables as arguments), any failing
3088 command will cause "run" to terminate, i. e. the remaining
3089 variables are not executed.
3091 Note for Redundant Ethernet Interfaces:
3092 =======================================
3094 Some boards come with redundant Ethernet interfaces; U-Boot supports
3095 such configurations and is capable of automatic selection of a
3096 "working" interface when needed. MAC assignment works as follows:
3098 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3099 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3100 "eth1addr" (=>eth1), "eth2addr", ...
3102 If the network interface stores some valid MAC address (for instance
3103 in SROM), this is used as default address if there is NO correspon-
3104 ding setting in the environment; if the corresponding environment
3105 variable is set, this overrides the settings in the card; that means:
3107 o If the SROM has a valid MAC address, and there is no address in the
3108 environment, the SROM's address is used.
3110 o If there is no valid address in the SROM, and a definition in the
3111 environment exists, then the value from the environment variable is
3114 o If both the SROM and the environment contain a MAC address, and
3115 both addresses are the same, this MAC address is used.
3117 o If both the SROM and the environment contain a MAC address, and the
3118 addresses differ, the value from the environment is used and a
3121 o If neither SROM nor the environment contain a MAC address, an error
3128 U-Boot is capable of booting (and performing other auxiliary operations on)
3129 images in two formats:
3131 New uImage format (FIT)
3132 -----------------------
3134 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3135 to Flattened Device Tree). It allows the use of images with multiple
3136 components (several kernels, ramdisks, etc.), with contents protected by
3137 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3143 Old image format is based on binary files which can be basically anything,
3144 preceded by a special header; see the definitions in include/image.h for
3145 details; basically, the header defines the following image properties:
3147 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3148 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3149 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3150 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3152 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3153 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3154 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3155 * Compression Type (uncompressed, gzip, bzip2)
3161 The header is marked by a special Magic Number, and both the header
3162 and the data portions of the image are secured against corruption by
3169 Although U-Boot should support any OS or standalone application
3170 easily, the main focus has always been on Linux during the design of
3173 U-Boot includes many features that so far have been part of some
3174 special "boot loader" code within the Linux kernel. Also, any
3175 "initrd" images to be used are no longer part of one big Linux image;
3176 instead, kernel and "initrd" are separate images. This implementation
3177 serves several purposes:
3179 - the same features can be used for other OS or standalone
3180 applications (for instance: using compressed images to reduce the
3181 Flash memory footprint)
3183 - it becomes much easier to port new Linux kernel versions because
3184 lots of low-level, hardware dependent stuff are done by U-Boot
3186 - the same Linux kernel image can now be used with different "initrd"
3187 images; of course this also means that different kernel images can
3188 be run with the same "initrd". This makes testing easier (you don't
3189 have to build a new "zImage.initrd" Linux image when you just
3190 change a file in your "initrd"). Also, a field-upgrade of the
3191 software is easier now.
3197 Porting Linux to U-Boot based systems:
3198 ---------------------------------------
3200 U-Boot cannot save you from doing all the necessary modifications to
3201 configure the Linux device drivers for use with your target hardware
3202 (no, we don't intend to provide a full virtual machine interface to
3205 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3207 Just make sure your machine specific header file (for instance
3208 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3209 Information structure as we define in include/asm-<arch>/u-boot.h,
3210 and make sure that your definition of IMAP_ADDR uses the same value
3211 as your U-Boot configuration in CONFIG_SYS_IMMR.
3214 Configuring the Linux kernel:
3215 -----------------------------
3217 No specific requirements for U-Boot. Make sure you have some root
3218 device (initial ramdisk, NFS) for your target system.
3221 Building a Linux Image:
3222 -----------------------
3224 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3225 not used. If you use recent kernel source, a new build target
3226 "uImage" will exist which automatically builds an image usable by
3227 U-Boot. Most older kernels also have support for a "pImage" target,
3228 which was introduced for our predecessor project PPCBoot and uses a
3229 100% compatible format.
3238 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3239 encapsulate a compressed Linux kernel image with header information,
3240 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3242 * build a standard "vmlinux" kernel image (in ELF binary format):
3244 * convert the kernel into a raw binary image:
3246 ${CROSS_COMPILE}-objcopy -O binary \
3247 -R .note -R .comment \
3248 -S vmlinux linux.bin
3250 * compress the binary image:
3254 * package compressed binary image for U-Boot:
3256 mkimage -A ppc -O linux -T kernel -C gzip \
3257 -a 0 -e 0 -n "Linux Kernel Image" \
3258 -d linux.bin.gz uImage
3261 The "mkimage" tool can also be used to create ramdisk images for use
3262 with U-Boot, either separated from the Linux kernel image, or
3263 combined into one file. "mkimage" encapsulates the images with a 64
3264 byte header containing information about target architecture,
3265 operating system, image type, compression method, entry points, time
3266 stamp, CRC32 checksums, etc.
3268 "mkimage" can be called in two ways: to verify existing images and
3269 print the header information, or to build new images.
3271 In the first form (with "-l" option) mkimage lists the information
3272 contained in the header of an existing U-Boot image; this includes
3273 checksum verification:
3275 tools/mkimage -l image
3276 -l ==> list image header information
3278 The second form (with "-d" option) is used to build a U-Boot image
3279 from a "data file" which is used as image payload:
3281 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3282 -n name -d data_file image
3283 -A ==> set architecture to 'arch'
3284 -O ==> set operating system to 'os'
3285 -T ==> set image type to 'type'
3286 -C ==> set compression type 'comp'
3287 -a ==> set load address to 'addr' (hex)
3288 -e ==> set entry point to 'ep' (hex)
3289 -n ==> set image name to 'name'
3290 -d ==> use image data from 'datafile'
3292 Right now, all Linux kernels for PowerPC systems use the same load
3293 address (0x00000000), but the entry point address depends on the
3296 - 2.2.x kernels have the entry point at 0x0000000C,
3297 - 2.3.x and later kernels have the entry point at 0x00000000.
3299 So a typical call to build a U-Boot image would read:
3301 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3302 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3303 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3304 > examples/uImage.TQM850L
3305 Image Name: 2.4.4 kernel for TQM850L
3306 Created: Wed Jul 19 02:34:59 2000
3307 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3308 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3309 Load Address: 0x00000000
3310 Entry Point: 0x00000000
3312 To verify the contents of the image (or check for corruption):
3314 -> tools/mkimage -l examples/uImage.TQM850L
3315 Image Name: 2.4.4 kernel for TQM850L
3316 Created: Wed Jul 19 02:34:59 2000
3317 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3318 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3319 Load Address: 0x00000000
3320 Entry Point: 0x00000000
3322 NOTE: for embedded systems where boot time is critical you can trade
3323 speed for memory and install an UNCOMPRESSED image instead: this
3324 needs more space in Flash, but boots much faster since it does not
3325 need to be uncompressed:
3327 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3328 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3329 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3330 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3331 > examples/uImage.TQM850L-uncompressed
3332 Image Name: 2.4.4 kernel for TQM850L
3333 Created: Wed Jul 19 02:34:59 2000
3334 Image Type: PowerPC Linux Kernel Image (uncompressed)
3335 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3336 Load Address: 0x00000000
3337 Entry Point: 0x00000000
3340 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3341 when your kernel is intended to use an initial ramdisk:
3343 -> tools/mkimage -n 'Simple Ramdisk Image' \
3344 > -A ppc -O linux -T ramdisk -C gzip \
3345 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3346 Image Name: Simple Ramdisk Image
3347 Created: Wed Jan 12 14:01:50 2000
3348 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3349 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3350 Load Address: 0x00000000
3351 Entry Point: 0x00000000
3354 Installing a Linux Image:
3355 -------------------------
3357 To downloading a U-Boot image over the serial (console) interface,
3358 you must convert the image to S-Record format:
3360 objcopy -I binary -O srec examples/image examples/image.srec
3362 The 'objcopy' does not understand the information in the U-Boot
3363 image header, so the resulting S-Record file will be relative to
3364 address 0x00000000. To load it to a given address, you need to
3365 specify the target address as 'offset' parameter with the 'loads'
3368 Example: install the image to address 0x40100000 (which on the
3369 TQM8xxL is in the first Flash bank):
3371 => erase 40100000 401FFFFF
3377 ## Ready for S-Record download ...
3378 ~>examples/image.srec
3379 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3381 15989 15990 15991 15992
3382 [file transfer complete]
3384 ## Start Addr = 0x00000000
3387 You can check the success of the download using the 'iminfo' command;
3388 this includes a checksum verification so you can be sure no data
3389 corruption happened:
3393 ## Checking Image at 40100000 ...
3394 Image Name: 2.2.13 for initrd on TQM850L
3395 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3396 Data Size: 335725 Bytes = 327 kB = 0 MB
3397 Load Address: 00000000
3398 Entry Point: 0000000c
3399 Verifying Checksum ... OK
3405 The "bootm" command is used to boot an application that is stored in
3406 memory (RAM or Flash). In case of a Linux kernel image, the contents
3407 of the "bootargs" environment variable is passed to the kernel as
3408 parameters. You can check and modify this variable using the
3409 "printenv" and "setenv" commands:
3412 => printenv bootargs
3413 bootargs=root=/dev/ram
3415 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3417 => printenv bootargs
3418 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3421 ## Booting Linux kernel at 40020000 ...
3422 Image Name: 2.2.13 for NFS on TQM850L
3423 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3424 Data Size: 381681 Bytes = 372 kB = 0 MB
3425 Load Address: 00000000
3426 Entry Point: 0000000c
3427 Verifying Checksum ... OK
3428 Uncompressing Kernel Image ... OK
3429 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
3430 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3431 time_init: decrementer frequency = 187500000/60
3432 Calibrating delay loop... 49.77 BogoMIPS
3433 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3436 If you want to boot a Linux kernel with initial RAM disk, you pass
3437 the memory addresses of both the kernel and the initrd image (PPBCOOT
3438 format!) to the "bootm" command:
3440 => imi 40100000 40200000
3442 ## Checking Image at 40100000 ...
3443 Image Name: 2.2.13 for initrd on TQM850L
3444 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3445 Data Size: 335725 Bytes = 327 kB = 0 MB
3446 Load Address: 00000000
3447 Entry Point: 0000000c
3448 Verifying Checksum ... OK
3450 ## Checking Image at 40200000 ...
3451 Image Name: Simple Ramdisk Image
3452 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3453 Data Size: 566530 Bytes = 553 kB = 0 MB
3454 Load Address: 00000000
3455 Entry Point: 00000000
3456 Verifying Checksum ... OK
3458 => bootm 40100000 40200000
3459 ## Booting Linux kernel at 40100000 ...
3460 Image Name: 2.2.13 for initrd on TQM850L
3461 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3462 Data Size: 335725 Bytes = 327 kB = 0 MB
3463 Load Address: 00000000
3464 Entry Point: 0000000c
3465 Verifying Checksum ... OK
3466 Uncompressing Kernel Image ... OK
3467 ## Loading RAMDisk Image at 40200000 ...
3468 Image Name: Simple Ramdisk Image
3469 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3470 Data Size: 566530 Bytes = 553 kB = 0 MB
3471 Load Address: 00000000
3472 Entry Point: 00000000
3473 Verifying Checksum ... OK
3474 Loading Ramdisk ... OK
3475 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
3476 Boot arguments: root=/dev/ram
3477 time_init: decrementer frequency = 187500000/60
3478 Calibrating delay loop... 49.77 BogoMIPS
3480 RAMDISK: Compressed image found at block 0
3481 VFS: Mounted root (ext2 filesystem).
3485 Boot Linux and pass a flat device tree:
3488 First, U-Boot must be compiled with the appropriate defines. See the section
3489 titled "Linux Kernel Interface" above for a more in depth explanation. The
3490 following is an example of how to start a kernel and pass an updated
3496 oft=oftrees/mpc8540ads.dtb
3497 => tftp $oftaddr $oft
3498 Speed: 1000, full duplex
3500 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3501 Filename 'oftrees/mpc8540ads.dtb'.
3502 Load address: 0x300000
3505 Bytes transferred = 4106 (100a hex)
3506 => tftp $loadaddr $bootfile
3507 Speed: 1000, full duplex
3509 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3511 Load address: 0x200000
3512 Loading:############
3514 Bytes transferred = 1029407 (fb51f hex)
3519 => bootm $loadaddr - $oftaddr
3520 ## Booting image at 00200000 ...
3521 Image Name: Linux-2.6.17-dirty
3522 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3523 Data Size: 1029343 Bytes = 1005.2 kB
3524 Load Address: 00000000
3525 Entry Point: 00000000
3526 Verifying Checksum ... OK
3527 Uncompressing Kernel Image ... OK
3528 Booting using flat device tree at 0x300000
3529 Using MPC85xx ADS machine description
3530 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3534 More About U-Boot Image Types:
3535 ------------------------------
3537 U-Boot supports the following image types:
3539 "Standalone Programs" are directly runnable in the environment
3540 provided by U-Boot; it is expected that (if they behave
3541 well) you can continue to work in U-Boot after return from
3542 the Standalone Program.
3543 "OS Kernel Images" are usually images of some Embedded OS which
3544 will take over control completely. Usually these programs
3545 will install their own set of exception handlers, device
3546 drivers, set up the MMU, etc. - this means, that you cannot
3547 expect to re-enter U-Boot except by resetting the CPU.
3548 "RAMDisk Images" are more or less just data blocks, and their
3549 parameters (address, size) are passed to an OS kernel that is
3551 "Multi-File Images" contain several images, typically an OS
3552 (Linux) kernel image and one or more data images like
3553 RAMDisks. This construct is useful for instance when you want
3554 to boot over the network using BOOTP etc., where the boot
3555 server provides just a single image file, but you want to get
3556 for instance an OS kernel and a RAMDisk image.
3558 "Multi-File Images" start with a list of image sizes, each
3559 image size (in bytes) specified by an "uint32_t" in network
3560 byte order. This list is terminated by an "(uint32_t)0".
3561 Immediately after the terminating 0 follow the images, one by
3562 one, all aligned on "uint32_t" boundaries (size rounded up to
3563 a multiple of 4 bytes).
3565 "Firmware Images" are binary images containing firmware (like
3566 U-Boot or FPGA images) which usually will be programmed to
3569 "Script files" are command sequences that will be executed by
3570 U-Boot's command interpreter; this feature is especially
3571 useful when you configure U-Boot to use a real shell (hush)
3572 as command interpreter.
3578 One of the features of U-Boot is that you can dynamically load and
3579 run "standalone" applications, which can use some resources of
3580 U-Boot like console I/O functions or interrupt services.
3582 Two simple examples are included with the sources:
3587 'examples/hello_world.c' contains a small "Hello World" Demo
3588 application; it is automatically compiled when you build U-Boot.
3589 It's configured to run at address 0x00040004, so you can play with it
3593 ## Ready for S-Record download ...
3594 ~>examples/hello_world.srec
3595 1 2 3 4 5 6 7 8 9 10 11 ...
3596 [file transfer complete]
3598 ## Start Addr = 0x00040004
3600 => go 40004 Hello World! This is a test.
3601 ## Starting application at 0x00040004 ...
3612 Hit any key to exit ...
3614 ## Application terminated, rc = 0x0
3616 Another example, which demonstrates how to register a CPM interrupt
3617 handler with the U-Boot code, can be found in 'examples/timer.c'.
3618 Here, a CPM timer is set up to generate an interrupt every second.
3619 The interrupt service routine is trivial, just printing a '.'
3620 character, but this is just a demo program. The application can be
3621 controlled by the following keys:
3623 ? - print current values og the CPM Timer registers
3624 b - enable interrupts and start timer
3625 e - stop timer and disable interrupts
3626 q - quit application
3629 ## Ready for S-Record download ...
3630 ~>examples/timer.srec
3631 1 2 3 4 5 6 7 8 9 10 11 ...
3632 [file transfer complete]
3634 ## Start Addr = 0x00040004
3637 ## Starting application at 0x00040004 ...
3640 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3643 [q, b, e, ?] Set interval 1000000 us
3646 [q, b, e, ?] ........
3647 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3650 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3653 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3656 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3658 [q, b, e, ?] ...Stopping timer
3660 [q, b, e, ?] ## Application terminated, rc = 0x0
3666 Over time, many people have reported problems when trying to use the
3667 "minicom" terminal emulation program for serial download. I (wd)
3668 consider minicom to be broken, and recommend not to use it. Under
3669 Unix, I recommend to use C-Kermit for general purpose use (and
3670 especially for kermit binary protocol download ("loadb" command), and
3671 use "cu" for S-Record download ("loads" command).
3673 Nevertheless, if you absolutely want to use it try adding this
3674 configuration to your "File transfer protocols" section:
3676 Name Program Name U/D FullScr IO-Red. Multi
3677 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3678 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3684 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3685 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3687 Building requires a cross environment; it is known to work on
3688 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3689 need gmake since the Makefiles are not compatible with BSD make).
3690 Note that the cross-powerpc package does not install include files;
3691 attempting to build U-Boot will fail because <machine/ansi.h> is
3692 missing. This file has to be installed and patched manually:
3694 # cd /usr/pkg/cross/powerpc-netbsd/include
3696 # ln -s powerpc machine
3697 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3698 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3700 Native builds *don't* work due to incompatibilities between native
3701 and U-Boot include files.
3703 Booting assumes that (the first part of) the image booted is a
3704 stage-2 loader which in turn loads and then invokes the kernel
3705 proper. Loader sources will eventually appear in the NetBSD source
3706 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3707 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3710 Implementation Internals:
3711 =========================
3713 The following is not intended to be a complete description of every
3714 implementation detail. However, it should help to understand the
3715 inner workings of U-Boot and make it easier to port it to custom
3719 Initial Stack, Global Data:
3720 ---------------------------
3722 The implementation of U-Boot is complicated by the fact that U-Boot
3723 starts running out of ROM (flash memory), usually without access to
3724 system RAM (because the memory controller is not initialized yet).
3725 This means that we don't have writable Data or BSS segments, and BSS
3726 is not initialized as zero. To be able to get a C environment working
3727 at all, we have to allocate at least a minimal stack. Implementation
3728 options for this are defined and restricted by the CPU used: Some CPU
3729 models provide on-chip memory (like the IMMR area on MPC8xx and
3730 MPC826x processors), on others (parts of) the data cache can be
3731 locked as (mis-) used as memory, etc.
3733 Chris Hallinan posted a good summary of these issues to the
3734 u-boot-users mailing list:
3736 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3737 From: "Chris Hallinan" <clh@net1plus.com>
3738 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3741 Correct me if I'm wrong, folks, but the way I understand it
3742 is this: Using DCACHE as initial RAM for Stack, etc, does not
3743 require any physical RAM backing up the cache. The cleverness
3744 is that the cache is being used as a temporary supply of
3745 necessary storage before the SDRAM controller is setup. It's
3746 beyond the scope of this list to explain the details, but you
3747 can see how this works by studying the cache architecture and
3748 operation in the architecture and processor-specific manuals.
3750 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3751 is another option for the system designer to use as an
3752 initial stack/RAM area prior to SDRAM being available. Either
3753 option should work for you. Using CS 4 should be fine if your
3754 board designers haven't used it for something that would
3755 cause you grief during the initial boot! It is frequently not
3758 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3759 with your processor/board/system design. The default value
3760 you will find in any recent u-boot distribution in
3761 walnut.h should work for you. I'd set it to a value larger
3762 than your SDRAM module. If you have a 64MB SDRAM module, set
3763 it above 400_0000. Just make sure your board has no resources
3764 that are supposed to respond to that address! That code in
3765 start.S has been around a while and should work as is when
3766 you get the config right.
3771 It is essential to remember this, since it has some impact on the C
3772 code for the initialization procedures:
3774 * Initialized global data (data segment) is read-only. Do not attempt
3777 * Do not use any uninitialized global data (or implicitely initialized
3778 as zero data - BSS segment) at all - this is undefined, initiali-
3779 zation is performed later (when relocating to RAM).
3781 * Stack space is very limited. Avoid big data buffers or things like
3784 Having only the stack as writable memory limits means we cannot use
3785 normal global data to share information beween the code. But it
3786 turned out that the implementation of U-Boot can be greatly
3787 simplified by making a global data structure (gd_t) available to all
3788 functions. We could pass a pointer to this data as argument to _all_
3789 functions, but this would bloat the code. Instead we use a feature of
3790 the GCC compiler (Global Register Variables) to share the data: we
3791 place a pointer (gd) to the global data into a register which we
3792 reserve for this purpose.
3794 When choosing a register for such a purpose we are restricted by the
3795 relevant (E)ABI specifications for the current architecture, and by
3796 GCC's implementation.
3798 For PowerPC, the following registers have specific use:
3800 R2: reserved for system use
3801 R3-R4: parameter passing and return values
3802 R5-R10: parameter passing
3803 R13: small data area pointer
3807 (U-Boot also uses R14 as internal GOT pointer.)
3809 ==> U-Boot will use R2 to hold a pointer to the global data
3811 Note: on PPC, we could use a static initializer (since the
3812 address of the global data structure is known at compile time),
3813 but it turned out that reserving a register results in somewhat
3814 smaller code - although the code savings are not that big (on
3815 average for all boards 752 bytes for the whole U-Boot image,
3816 624 text + 127 data).
3818 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3819 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3821 ==> U-Boot will use P5 to hold a pointer to the global data
3823 On ARM, the following registers are used:
3825 R0: function argument word/integer result
3826 R1-R3: function argument word
3828 R10: stack limit (used only if stack checking if enabled)
3829 R11: argument (frame) pointer
3830 R12: temporary workspace
3833 R15: program counter
3835 ==> U-Boot will use R8 to hold a pointer to the global data
3837 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3838 or current versions of GCC may "optimize" the code too much.
3843 U-Boot runs in system state and uses physical addresses, i.e. the
3844 MMU is not used either for address mapping nor for memory protection.
3846 The available memory is mapped to fixed addresses using the memory
3847 controller. In this process, a contiguous block is formed for each
3848 memory type (Flash, SDRAM, SRAM), even when it consists of several
3849 physical memory banks.
3851 U-Boot is installed in the first 128 kB of the first Flash bank (on
3852 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3853 booting and sizing and initializing DRAM, the code relocates itself
3854 to the upper end of DRAM. Immediately below the U-Boot code some
3855 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3856 configuration setting]. Below that, a structure with global Board
3857 Info data is placed, followed by the stack (growing downward).
3859 Additionally, some exception handler code is copied to the low 8 kB
3860 of DRAM (0x00000000 ... 0x00001FFF).
3862 So a typical memory configuration with 16 MB of DRAM could look like
3865 0x0000 0000 Exception Vector code
3868 0x0000 2000 Free for Application Use
3874 0x00FB FF20 Monitor Stack (Growing downward)
3875 0x00FB FFAC Board Info Data and permanent copy of global data
3876 0x00FC 0000 Malloc Arena
3879 0x00FE 0000 RAM Copy of Monitor Code
3880 ... eventually: LCD or video framebuffer
3881 ... eventually: pRAM (Protected RAM - unchanged by reset)
3882 0x00FF FFFF [End of RAM]
3885 System Initialization:
3886 ----------------------
3888 In the reset configuration, U-Boot starts at the reset entry point
3889 (on most PowerPC systems at address 0x00000100). Because of the reset
3890 configuration for CS0# this is a mirror of the onboard Flash memory.
3891 To be able to re-map memory U-Boot then jumps to its link address.
3892 To be able to implement the initialization code in C, a (small!)
3893 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3894 which provide such a feature like MPC8xx or MPC8260), or in a locked
3895 part of the data cache. After that, U-Boot initializes the CPU core,
3896 the caches and the SIU.
3898 Next, all (potentially) available memory banks are mapped using a
3899 preliminary mapping. For example, we put them on 512 MB boundaries
3900 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3901 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3902 programmed for SDRAM access. Using the temporary configuration, a
3903 simple memory test is run that determines the size of the SDRAM
3906 When there is more than one SDRAM bank, and the banks are of
3907 different size, the largest is mapped first. For equal size, the first
3908 bank (CS2#) is mapped first. The first mapping is always for address
3909 0x00000000, with any additional banks following immediately to create
3910 contiguous memory starting from 0.
3912 Then, the monitor installs itself at the upper end of the SDRAM area
3913 and allocates memory for use by malloc() and for the global Board
3914 Info data; also, the exception vector code is copied to the low RAM
3915 pages, and the final stack is set up.
3917 Only after this relocation will you have a "normal" C environment;
3918 until that you are restricted in several ways, mostly because you are
3919 running from ROM, and because the code will have to be relocated to a
3923 U-Boot Porting Guide:
3924 ----------------------
3926 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3930 int main (int argc, char *argv[])
3932 sighandler_t no_more_time;
3934 signal (SIGALRM, no_more_time);
3935 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3937 if (available_money > available_manpower) {
3938 pay consultant to port U-Boot;
3942 Download latest U-Boot source;
3944 Subscribe to u-boot-users mailing list;
3947 email ("Hi, I am new to U-Boot, how do I get started?");
3951 Read the README file in the top level directory;
3952 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3953 Read the source, Luke;
3956 if (available_money > toLocalCurrency ($2500)) {
3959 Add a lot of aggravation and time;
3962 Create your own board support subdirectory;
3964 Create your own board config file;
3968 Add / modify source code;
3972 email ("Hi, I am having problems...");
3974 Send patch file to Wolfgang;
3979 void no_more_time (int sig)
3988 All contributions to U-Boot should conform to the Linux kernel
3989 coding style; see the file "Documentation/CodingStyle" and the script
3990 "scripts/Lindent" in your Linux kernel source directory. In sources
3991 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3992 spaces before parameters to function calls) is actually used.
3994 Source files originating from a different project (for example the
3995 MTD subsystem) are generally exempt from these guidelines and are not
3996 reformated to ease subsequent migration to newer versions of those
3999 Please note that U-Boot is implemented in C (and to some small parts in
4000 Assembler); no C++ is used, so please do not use C++ style comments (//)
4003 Please also stick to the following formatting rules:
4004 - remove any trailing white space
4005 - use TAB characters for indentation, not spaces
4006 - make sure NOT to use DOS '\r\n' line feeds
4007 - do not add more than 2 empty lines to source files
4008 - do not add trailing empty lines to source files
4010 Submissions which do not conform to the standards may be returned
4011 with a request to reformat the changes.
4017 Since the number of patches for U-Boot is growing, we need to
4018 establish some rules. Submissions which do not conform to these rules
4019 may be rejected, even when they contain important and valuable stuff.
4021 Patches shall be sent to the u-boot-users mailing list.
4023 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4025 When you send a patch, please include the following information with
4028 * For bug fixes: a description of the bug and how your patch fixes
4029 this bug. Please try to include a way of demonstrating that the
4030 patch actually fixes something.
4032 * For new features: a description of the feature and your
4035 * A CHANGELOG entry as plaintext (separate from the patch)
4037 * For major contributions, your entry to the CREDITS file
4039 * When you add support for a new board, don't forget to add this
4040 board to the MAKEALL script, too.
4042 * If your patch adds new configuration options, don't forget to
4043 document these in the README file.
4045 * The patch itself. If you are using git (which is *strongly*
4046 recommended) you can easily generate the patch using the
4047 "git-format-patch". If you then use "git-send-email" to send it to
4048 the U-Boot mailing list, you will avoid most of the common problems
4049 with some other mail clients.
4051 If you cannot use git, use "diff -purN OLD NEW". If your version of
4052 diff does not support these options, then get the latest version of
4055 The current directory when running this command shall be the parent
4056 directory of the U-Boot source tree (i. e. please make sure that
4057 your patch includes sufficient directory information for the
4060 We prefer patches as plain text. MIME attachments are discouraged,
4061 and compressed attachments must not be used.
4063 * If one logical set of modifications affects or creates several
4064 files, all these changes shall be submitted in a SINGLE patch file.
4066 * Changesets that contain different, unrelated modifications shall be
4067 submitted as SEPARATE patches, one patch per changeset.
4072 * Before sending the patch, run the MAKEALL script on your patched
4073 source tree and make sure that no errors or warnings are reported
4074 for any of the boards.
4076 * Keep your modifications to the necessary minimum: A patch
4077 containing several unrelated changes or arbitrary reformats will be
4078 returned with a request to re-formatting / split it.
4080 * If you modify existing code, make sure that your new code does not
4081 add to the memory footprint of the code ;-) Small is beautiful!
4082 When adding new features, these should compile conditionally only
4083 (using #ifdef), and the resulting code with the new feature
4084 disabled must not need more memory than the old code without your
4087 * Remember that there is a size limit of 40 kB per message on the
4088 u-boot-users mailing list. Bigger patches will be moderated. If
4089 they are reasonable and not bigger than 100 kB, they will be
4090 acknowledged. Even bigger patches should be avoided.
projects / people / ms / u-boot.git / blob