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_DS4510 * ds4510 I2C gpio commands
596 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
597 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
598 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
599 CONFIG_CMD_DTT * Digital Therm and Thermostat
600 CONFIG_CMD_ECHO echo arguments
601 CONFIG_CMD_EEPROM * EEPROM read/write support
602 CONFIG_CMD_ELF * bootelf, bootvx
603 CONFIG_CMD_ENV saveenv
604 CONFIG_CMD_FDC * Floppy Disk Support
605 CONFIG_CMD_FAT * FAT partition support
606 CONFIG_CMD_FDOS * Dos diskette Support
607 CONFIG_CMD_FLASH flinfo, erase, protect
608 CONFIG_CMD_FPGA FPGA device initialization support
609 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
610 CONFIG_CMD_I2C * I2C serial bus support
611 CONFIG_CMD_IDE * IDE harddisk support
612 CONFIG_CMD_IMI iminfo
613 CONFIG_CMD_IMLS List all found images
614 CONFIG_CMD_IMMAP * IMMR dump support
615 CONFIG_CMD_IRQ * irqinfo
616 CONFIG_CMD_ITEST Integer/string test of 2 values
617 CONFIG_CMD_JFFS2 * JFFS2 Support
618 CONFIG_CMD_KGDB * kgdb
619 CONFIG_CMD_LOADB loadb
620 CONFIG_CMD_LOADS loads
621 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
623 CONFIG_CMD_MISC Misc functions like sleep etc
624 CONFIG_CMD_MMC * MMC memory mapped support
625 CONFIG_CMD_MII * MII utility commands
626 CONFIG_CMD_NAND * NAND support
627 CONFIG_CMD_NET bootp, tftpboot, rarpboot
628 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
629 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
630 CONFIG_CMD_PCI * pciinfo
631 CONFIG_CMD_PCMCIA * PCMCIA support
632 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
634 CONFIG_CMD_PORTIO * Port I/O
635 CONFIG_CMD_REGINFO * Register dump
636 CONFIG_CMD_RUN run command in env variable
637 CONFIG_CMD_SAVES * save S record dump
638 CONFIG_CMD_SCSI * SCSI Support
639 CONFIG_CMD_SDRAM * print SDRAM configuration information
640 (requires CONFIG_CMD_I2C)
641 CONFIG_CMD_SETGETDCR Support for DCR Register access
643 CONFIG_CMD_SPI * SPI serial bus support
644 CONFIG_CMD_USB * USB support
645 CONFIG_CMD_VFD * VFD support (TRAB)
646 CONFIG_CMD_CDP * Cisco Discover Protocol support
647 CONFIG_CMD_FSL * Microblaze FSL support
650 EXAMPLE: If you want all functions except of network
651 support you can write:
653 #include "config_cmd_all.h"
654 #undef CONFIG_CMD_NET
657 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
659 Note: Don't enable the "icache" and "dcache" commands
660 (configuration option CONFIG_CMD_CACHE) unless you know
661 what you (and your U-Boot users) are doing. Data
662 cache cannot be enabled on systems like the 8xx or
663 8260 (where accesses to the IMMR region must be
664 uncached), and it cannot be disabled on all other
665 systems where we (mis-) use the data cache to hold an
666 initial stack and some data.
669 XXX - this list needs to get updated!
673 If this variable is defined, it enables watchdog
674 support. There must be support in the platform specific
675 code for a watchdog. For the 8xx and 8260 CPUs, the
676 SIU Watchdog feature is enabled in the SYPCR
680 CONFIG_VERSION_VARIABLE
681 If this variable is defined, an environment variable
682 named "ver" is created by U-Boot showing the U-Boot
683 version as printed by the "version" command.
684 This variable is readonly.
688 When CONFIG_CMD_DATE is selected, the type of the RTC
689 has to be selected, too. Define exactly one of the
692 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
693 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
694 CONFIG_RTC_MC13783 - use MC13783 RTC
695 CONFIG_RTC_MC146818 - use MC146818 RTC
696 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
697 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
698 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
699 CONFIG_RTC_DS164x - use Dallas DS164x RTC
700 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
701 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
702 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
704 Note that if the RTC uses I2C, then the I2C interface
705 must also be configured. See I2C Support, below.
708 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
709 CONFIG_PCA953X_INFO - enable pca953x info command
711 Note that if the GPIO device uses I2C, then the I2C interface
712 must also be configured. See I2C Support, below.
716 When CONFIG_TIMESTAMP is selected, the timestamp
717 (date and time) of an image is printed by image
718 commands like bootm or iminfo. This option is
719 automatically enabled when you select CONFIG_CMD_DATE .
722 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
723 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
725 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
726 CONFIG_CMD_SCSI) you must configure support for at
727 least one partition type as well.
730 CONFIG_IDE_RESET_ROUTINE - this is defined in several
731 board configurations files but used nowhere!
733 CONFIG_IDE_RESET - is this is defined, IDE Reset will
734 be performed by calling the function
735 ide_set_reset(int reset)
736 which has to be defined in a board specific file
741 Set this to enable ATAPI support.
746 Set this to enable support for disks larger than 137GB
747 Also look at CONFIG_SYS_64BIT_LBA ,CONFIG_SYS_64BIT_VSPRINTF and CONFIG_SYS_64BIT_STRTOUL
748 Whithout these , LBA48 support uses 32bit variables and will 'only'
749 support disks up to 2.1TB.
751 CONFIG_SYS_64BIT_LBA:
752 When enabled, makes the IDE subsystem use 64bit sector addresses.
756 At the moment only there is only support for the
757 SYM53C8XX SCSI controller; define
758 CONFIG_SCSI_SYM53C8XX to enable it.
760 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
761 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
762 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
763 maximum numbers of LUNs, SCSI ID's and target
765 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
767 - NETWORK Support (PCI):
769 Support for Intel 8254x gigabit chips.
771 CONFIG_E1000_FALLBACK_MAC
772 default MAC for empty EEPROM after production.
775 Support for Intel 82557/82559/82559ER chips.
776 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
777 write routine for first time initialisation.
780 Support for Digital 2114x chips.
781 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
782 modem chip initialisation (KS8761/QS6611).
785 Support for National dp83815 chips.
788 Support for National dp8382[01] gigabit chips.
790 - NETWORK Support (other):
792 CONFIG_DRIVER_LAN91C96
793 Support for SMSC's LAN91C96 chips.
796 Define this to hold the physical address
797 of the LAN91C96's I/O space
799 CONFIG_LAN91C96_USE_32_BIT
800 Define this to enable 32 bit addressing
802 CONFIG_DRIVER_SMC91111
803 Support for SMSC's LAN91C111 chip
806 Define this to hold the physical address
807 of the device (I/O space)
809 CONFIG_SMC_USE_32_BIT
810 Define this if data bus is 32 bits
812 CONFIG_SMC_USE_IOFUNCS
813 Define this to use i/o functions instead of macros
814 (some hardware wont work with macros)
816 CONFIG_DRIVER_SMC911X
817 Support for SMSC's LAN911x and LAN921x chips
819 CONFIG_DRIVER_SMC911X_BASE
820 Define this to hold the physical address
821 of the device (I/O space)
823 CONFIG_DRIVER_SMC911X_32_BIT
824 Define this if data bus is 32 bits
826 CONFIG_DRIVER_SMC911X_16_BIT
827 Define this if data bus is 16 bits. If your processor
828 automatically converts one 32 bit word to two 16 bit
829 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
832 At the moment only the UHCI host controller is
833 supported (PIP405, MIP405, MPC5200); define
834 CONFIG_USB_UHCI to enable it.
835 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
836 and define CONFIG_USB_STORAGE to enable the USB
839 Supported are USB Keyboards and USB Floppy drives
841 MPC5200 USB requires additional defines:
843 for 528 MHz Clock: 0x0001bbbb
845 for differential drivers: 0x00001000
846 for single ended drivers: 0x00005000
847 CONFIG_SYS_USB_EVENT_POLL
848 May be defined to allow interrupt polling
849 instead of using asynchronous interrupts
852 Define the below if you wish to use the USB console.
853 Once firmware is rebuilt from a serial console issue the
854 command "setenv stdin usbtty; setenv stdout usbtty" and
855 attach your USB cable. The Unix command "dmesg" should print
856 it has found a new device. The environment variable usbtty
857 can be set to gserial or cdc_acm to enable your device to
858 appear to a USB host as a Linux gserial device or a
859 Common Device Class Abstract Control Model serial device.
860 If you select usbtty = gserial you should be able to enumerate
862 # modprobe usbserial vendor=0xVendorID product=0xProductID
863 else if using cdc_acm, simply setting the environment
864 variable usbtty to be cdc_acm should suffice. The following
865 might be defined in YourBoardName.h
868 Define this to build a UDC device
871 Define this to have a tty type of device available to
872 talk to the UDC device
874 CONFIG_SYS_CONSOLE_IS_IN_ENV
875 Define this if you want stdin, stdout &/or stderr to
879 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
880 Derive USB clock from external clock "blah"
881 - CONFIG_SYS_USB_EXTC_CLK 0x02
883 CONFIG_SYS_USB_BRG_CLK 0xBLAH
884 Derive USB clock from brgclk
885 - CONFIG_SYS_USB_BRG_CLK 0x04
887 If you have a USB-IF assigned VendorID then you may wish to
888 define your own vendor specific values either in BoardName.h
889 or directly in usbd_vendor_info.h. If you don't define
890 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
891 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
892 should pretend to be a Linux device to it's target host.
894 CONFIG_USBD_MANUFACTURER
895 Define this string as the name of your company for
896 - CONFIG_USBD_MANUFACTURER "my company"
898 CONFIG_USBD_PRODUCT_NAME
899 Define this string as the name of your product
900 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
903 Define this as your assigned Vendor ID from the USB
904 Implementors Forum. This *must* be a genuine Vendor ID
905 to avoid polluting the USB namespace.
906 - CONFIG_USBD_VENDORID 0xFFFF
908 CONFIG_USBD_PRODUCTID
909 Define this as the unique Product ID
911 - CONFIG_USBD_PRODUCTID 0xFFFF
915 The MMC controller on the Intel PXA is supported. To
916 enable this define CONFIG_MMC. The MMC can be
917 accessed from the boot prompt by mapping the device
918 to physical memory similar to flash. Command line is
919 enabled with CONFIG_CMD_MMC. The MMC driver also works with
920 the FAT fs. This is enabled with CONFIG_CMD_FAT.
922 - Journaling Flash filesystem support:
923 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
924 CONFIG_JFFS2_NAND_DEV
925 Define these for a default partition on a NAND device
927 CONFIG_SYS_JFFS2_FIRST_SECTOR,
928 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
929 Define these for a default partition on a NOR device
931 CONFIG_SYS_JFFS_CUSTOM_PART
932 Define this to create an own partition. You have to provide a
933 function struct part_info* jffs2_part_info(int part_num)
935 If you define only one JFFS2 partition you may also want to
936 #define CONFIG_SYS_JFFS_SINGLE_PART 1
937 to disable the command chpart. This is the default when you
938 have not defined a custom partition
943 Define this to enable standard (PC-Style) keyboard
947 Standard PC keyboard driver with US (is default) and
948 GERMAN key layout (switch via environment 'keymap=de') support.
949 Export function i8042_kbd_init, i8042_tstc and i8042_getc
950 for cfb_console. Supports cursor blinking.
955 Define this to enable video support (for output to
960 Enable Chips & Technologies 69000 Video chip
962 CONFIG_VIDEO_SMI_LYNXEM
963 Enable Silicon Motion SMI 712/710/810 Video chip. The
964 video output is selected via environment 'videoout'
965 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
968 For the CT69000 and SMI_LYNXEM drivers, videomode is
969 selected via environment 'videomode'. Two different ways
971 - "videomode=num" 'num' is a standard LiLo mode numbers.
972 Following standard modes are supported (* is default):
974 Colors 640x480 800x600 1024x768 1152x864 1280x1024
975 -------------+---------------------------------------------
976 8 bits | 0x301* 0x303 0x305 0x161 0x307
977 15 bits | 0x310 0x313 0x316 0x162 0x319
978 16 bits | 0x311 0x314 0x317 0x163 0x31A
979 24 bits | 0x312 0x315 0x318 ? 0x31B
980 -------------+---------------------------------------------
981 (i.e. setenv videomode 317; saveenv; reset;)
983 - "videomode=bootargs" all the video parameters are parsed
984 from the bootargs. (See drivers/video/videomodes.c)
987 CONFIG_VIDEO_SED13806
988 Enable Epson SED13806 driver. This driver supports 8bpp
989 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
990 or CONFIG_VIDEO_SED13806_16BPP
995 Define this to enable a custom keyboard support.
996 This simply calls drv_keyboard_init() which must be
997 defined in your board-specific files.
998 The only board using this so far is RBC823.
1000 - LCD Support: CONFIG_LCD
1002 Define this to enable LCD support (for output to LCD
1003 display); also select one of the supported displays
1004 by defining one of these:
1008 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1010 CONFIG_NEC_NL6448AC33:
1012 NEC NL6448AC33-18. Active, color, single scan.
1014 CONFIG_NEC_NL6448BC20
1016 NEC NL6448BC20-08. 6.5", 640x480.
1017 Active, color, single scan.
1019 CONFIG_NEC_NL6448BC33_54
1021 NEC NL6448BC33-54. 10.4", 640x480.
1022 Active, color, single scan.
1026 Sharp 320x240. Active, color, single scan.
1027 It isn't 16x9, and I am not sure what it is.
1029 CONFIG_SHARP_LQ64D341
1031 Sharp LQ64D341 display, 640x480.
1032 Active, color, single scan.
1036 HLD1045 display, 640x480.
1037 Active, color, single scan.
1041 Optrex CBL50840-2 NF-FW 99 22 M5
1043 Hitachi LMG6912RPFC-00T
1047 320x240. Black & white.
1049 Normally display is black on white background; define
1050 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1052 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1054 If this option is set, the environment is checked for
1055 a variable "splashimage". If found, the usual display
1056 of logo, copyright and system information on the LCD
1057 is suppressed and the BMP image at the address
1058 specified in "splashimage" is loaded instead. The
1059 console is redirected to the "nulldev", too. This
1060 allows for a "silent" boot where a splash screen is
1061 loaded very quickly after power-on.
1063 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1065 If this option is set, additionally to standard BMP
1066 images, gzipped BMP images can be displayed via the
1067 splashscreen support or the bmp command.
1069 - Compression support:
1072 If this option is set, support for bzip2 compressed
1073 images is included. If not, only uncompressed and gzip
1074 compressed images are supported.
1076 NOTE: the bzip2 algorithm requires a lot of RAM, so
1077 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1082 If this option is set, support for lzma compressed
1085 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1086 requires an amount of dynamic memory that is given by the
1089 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1091 Where lc and lp stand for, respectively, Literal context bits
1092 and Literal pos bits.
1094 This value is upper-bounded by 14MB in the worst case. Anyway,
1095 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1096 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1097 a very small buffer.
1099 Use the lzmainfo tool to determinate the lc and lp values and
1100 then calculate the amount of needed dynamic memory (ensuring
1101 the appropriate CONFIG_SYS_MALLOC_LEN value).
1106 The address of PHY on MII bus.
1108 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1110 The clock frequency of the MII bus
1114 If this option is set, support for speed/duplex
1115 detection of gigabit PHY is included.
1117 CONFIG_PHY_RESET_DELAY
1119 Some PHY like Intel LXT971A need extra delay after
1120 reset before any MII register access is possible.
1121 For such PHY, set this option to the usec delay
1122 required. (minimum 300usec for LXT971A)
1124 CONFIG_PHY_CMD_DELAY (ppc4xx)
1126 Some PHY like Intel LXT971A need extra delay after
1127 command issued before MII status register can be read
1137 Define a default value for Ethernet address to use
1138 for the respective Ethernet interface, in case this
1139 is not determined automatically.
1144 Define a default value for the IP address to use for
1145 the default Ethernet interface, in case this is not
1146 determined through e.g. bootp.
1148 - Server IP address:
1151 Defines a default value for the IP address of a TFTP
1152 server to contact when using the "tftboot" command.
1154 - Multicast TFTP Mode:
1157 Defines whether you want to support multicast TFTP as per
1158 rfc-2090; for example to work with atftp. Lets lots of targets
1159 tftp down the same boot image concurrently. Note: the Ethernet
1160 driver in use must provide a function: mcast() to join/leave a
1163 CONFIG_BOOTP_RANDOM_DELAY
1164 - BOOTP Recovery Mode:
1165 CONFIG_BOOTP_RANDOM_DELAY
1167 If you have many targets in a network that try to
1168 boot using BOOTP, you may want to avoid that all
1169 systems send out BOOTP requests at precisely the same
1170 moment (which would happen for instance at recovery
1171 from a power failure, when all systems will try to
1172 boot, thus flooding the BOOTP server. Defining
1173 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1174 inserted before sending out BOOTP requests. The
1175 following delays are inserted then:
1177 1st BOOTP request: delay 0 ... 1 sec
1178 2nd BOOTP request: delay 0 ... 2 sec
1179 3rd BOOTP request: delay 0 ... 4 sec
1181 BOOTP requests: delay 0 ... 8 sec
1183 - DHCP Advanced Options:
1184 You can fine tune the DHCP functionality by defining
1185 CONFIG_BOOTP_* symbols:
1187 CONFIG_BOOTP_SUBNETMASK
1188 CONFIG_BOOTP_GATEWAY
1189 CONFIG_BOOTP_HOSTNAME
1190 CONFIG_BOOTP_NISDOMAIN
1191 CONFIG_BOOTP_BOOTPATH
1192 CONFIG_BOOTP_BOOTFILESIZE
1195 CONFIG_BOOTP_SEND_HOSTNAME
1196 CONFIG_BOOTP_NTPSERVER
1197 CONFIG_BOOTP_TIMEOFFSET
1198 CONFIG_BOOTP_VENDOREX
1200 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1201 environment variable, not the BOOTP server.
1203 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1204 serverip from a DHCP server, it is possible that more
1205 than one DNS serverip is offered to the client.
1206 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1207 serverip will be stored in the additional environment
1208 variable "dnsip2". The first DNS serverip is always
1209 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1212 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1213 to do a dynamic update of a DNS server. To do this, they
1214 need the hostname of the DHCP requester.
1215 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1216 of the "hostname" environment variable is passed as
1217 option 12 to the DHCP server.
1219 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1221 A 32bit value in microseconds for a delay between
1222 receiving a "DHCP Offer" and sending the "DHCP Request".
1223 This fixes a problem with certain DHCP servers that don't
1224 respond 100% of the time to a "DHCP request". E.g. On an
1225 AT91RM9200 processor running at 180MHz, this delay needed
1226 to be *at least* 15,000 usec before a Windows Server 2003
1227 DHCP server would reply 100% of the time. I recommend at
1228 least 50,000 usec to be safe. The alternative is to hope
1229 that one of the retries will be successful but note that
1230 the DHCP timeout and retry process takes a longer than
1234 CONFIG_CDP_DEVICE_ID
1236 The device id used in CDP trigger frames.
1238 CONFIG_CDP_DEVICE_ID_PREFIX
1240 A two character string which is prefixed to the MAC address
1245 A printf format string which contains the ascii name of
1246 the port. Normally is set to "eth%d" which sets
1247 eth0 for the first Ethernet, eth1 for the second etc.
1249 CONFIG_CDP_CAPABILITIES
1251 A 32bit integer which indicates the device capabilities;
1252 0x00000010 for a normal host which does not forwards.
1256 An ascii string containing the version of the software.
1260 An ascii string containing the name of the platform.
1264 A 32bit integer sent on the trigger.
1266 CONFIG_CDP_POWER_CONSUMPTION
1268 A 16bit integer containing the power consumption of the
1269 device in .1 of milliwatts.
1271 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1273 A byte containing the id of the VLAN.
1275 - Status LED: CONFIG_STATUS_LED
1277 Several configurations allow to display the current
1278 status using a LED. For instance, the LED will blink
1279 fast while running U-Boot code, stop blinking as
1280 soon as a reply to a BOOTP request was received, and
1281 start blinking slow once the Linux kernel is running
1282 (supported by a status LED driver in the Linux
1283 kernel). Defining CONFIG_STATUS_LED enables this
1286 - CAN Support: CONFIG_CAN_DRIVER
1288 Defining CONFIG_CAN_DRIVER enables CAN driver support
1289 on those systems that support this (optional)
1290 feature, like the TQM8xxL modules.
1292 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1294 These enable I2C serial bus commands. Defining either of
1295 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1296 include the appropriate I2C driver for the selected CPU.
1298 This will allow you to use i2c commands at the u-boot
1299 command line (as long as you set CONFIG_CMD_I2C in
1300 CONFIG_COMMANDS) and communicate with i2c based realtime
1301 clock chips. See common/cmd_i2c.c for a description of the
1302 command line interface.
1304 CONFIG_I2C_CMD_TREE is a recommended option that places
1305 all I2C commands under a single 'i2c' root command. The
1306 older 'imm', 'imd', 'iprobe' etc. commands are considered
1307 deprecated and may disappear in the future.
1309 CONFIG_HARD_I2C selects a hardware I2C controller.
1311 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1312 bit-banging) driver instead of CPM or similar hardware
1315 There are several other quantities that must also be
1316 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1318 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1319 to be the frequency (in Hz) at which you wish your i2c bus
1320 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1321 the CPU's i2c node address).
1323 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1324 sets the CPU up as a master node and so its address should
1325 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1326 p.16-473). So, set CONFIG_SYS_I2C_SLAVE to 0.
1328 That's all that's required for CONFIG_HARD_I2C.
1330 If you use the software i2c interface (CONFIG_SOFT_I2C)
1331 then the following macros need to be defined (examples are
1332 from include/configs/lwmon.h):
1336 (Optional). Any commands necessary to enable the I2C
1337 controller or configure ports.
1339 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1343 (Only for MPC8260 CPU). The I/O port to use (the code
1344 assumes both bits are on the same port). Valid values
1345 are 0..3 for ports A..D.
1349 The code necessary to make the I2C data line active
1350 (driven). If the data line is open collector, this
1353 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1357 The code necessary to make the I2C data line tri-stated
1358 (inactive). If the data line is open collector, this
1361 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1365 Code that returns TRUE if the I2C data line is high,
1368 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1372 If <bit> is TRUE, sets the I2C data line high. If it
1373 is FALSE, it clears it (low).
1375 eg: #define I2C_SDA(bit) \
1376 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1377 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1381 If <bit> is TRUE, sets the I2C clock line high. If it
1382 is FALSE, it clears it (low).
1384 eg: #define I2C_SCL(bit) \
1385 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1386 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1390 This delay is invoked four times per clock cycle so this
1391 controls the rate of data transfer. The data rate thus
1392 is 1 / (I2C_DELAY * 4). Often defined to be something
1395 #define I2C_DELAY udelay(2)
1397 CONFIG_SYS_I2C_INIT_BOARD
1399 When a board is reset during an i2c bus transfer
1400 chips might think that the current transfer is still
1401 in progress. On some boards it is possible to access
1402 the i2c SCLK line directly, either by using the
1403 processor pin as a GPIO or by having a second pin
1404 connected to the bus. If this option is defined a
1405 custom i2c_init_board() routine in boards/xxx/board.c
1406 is run early in the boot sequence.
1408 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1410 This option enables configuration of bi_iic_fast[] flags
1411 in u-boot bd_info structure based on u-boot environment
1412 variable "i2cfast". (see also i2cfast)
1414 CONFIG_I2C_MULTI_BUS
1416 This option allows the use of multiple I2C buses, each of which
1417 must have a controller. At any point in time, only one bus is
1418 active. To switch to a different bus, use the 'i2c dev' command.
1419 Note that bus numbering is zero-based.
1421 CONFIG_SYS_I2C_NOPROBES
1423 This option specifies a list of I2C devices that will be skipped
1424 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1425 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1426 pairs. Otherwise, specify a 1D array of device addresses
1429 #undef CONFIG_I2C_MULTI_BUS
1430 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1432 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1434 #define CONFIG_I2C_MULTI_BUS
1435 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1437 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1439 CONFIG_SYS_SPD_BUS_NUM
1441 If defined, then this indicates the I2C bus number for DDR SPD.
1442 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1444 CONFIG_SYS_RTC_BUS_NUM
1446 If defined, then this indicates the I2C bus number for the RTC.
1447 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1449 CONFIG_SYS_DTT_BUS_NUM
1451 If defined, then this indicates the I2C bus number for the DTT.
1452 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1454 CONFIG_SYS_I2C_DTT_ADDR:
1456 If defined, specifies the I2C address of the DTT device.
1457 If not defined, then U-Boot uses predefined value for
1458 specified DTT device.
1462 Define this option if you want to use Freescale's I2C driver in
1463 drivers/i2c/fsl_i2c.c.
1467 Define this option if you have I2C devices reached over 1 .. n
1468 I2C Muxes like the pca9544a. This option addes a new I2C
1469 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1470 new I2C Bus to the existing I2C Busses. If you select the
1471 new Bus with "i2c dev", u-bbot sends first the commandos for
1472 the muxes to activate this new "bus".
1474 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1478 Adding a new I2C Bus reached over 2 pca9544a muxes
1479 The First mux with address 70 and channel 6
1480 The Second mux with address 71 and channel 4
1482 => i2c bus pca9544a:70:6:pca9544a:71:4
1484 Use the "i2c bus" command without parameter, to get a list
1485 of I2C Busses with muxes:
1488 Busses reached over muxes:
1490 reached over Mux(es):
1493 reached over Mux(es):
1498 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1499 u-boot sends First the Commando to the mux@70 to enable
1500 channel 6, and then the Commando to the mux@71 to enable
1503 After that, you can use the "normal" i2c commands as
1504 usual, to communicate with your I2C devices behind
1507 This option is actually implemented for the bitbanging
1508 algorithm in common/soft_i2c.c and for the Hardware I2C
1509 Bus on the MPC8260. But it should be not so difficult
1510 to add this option to other architectures.
1513 - SPI Support: CONFIG_SPI
1515 Enables SPI driver (so far only tested with
1516 SPI EEPROM, also an instance works with Crystal A/D and
1517 D/As on the SACSng board)
1521 Enables extended (16-bit) SPI EEPROM addressing.
1522 (symmetrical to CONFIG_I2C_X)
1526 Enables a software (bit-bang) SPI driver rather than
1527 using hardware support. This is a general purpose
1528 driver that only requires three general I/O port pins
1529 (two outputs, one input) to function. If this is
1530 defined, the board configuration must define several
1531 SPI configuration items (port pins to use, etc). For
1532 an example, see include/configs/sacsng.h.
1536 Enables a hardware SPI driver for general-purpose reads
1537 and writes. As with CONFIG_SOFT_SPI, the board configuration
1538 must define a list of chip-select function pointers.
1539 Currently supported on some MPC8xxx processors. For an
1540 example, see include/configs/mpc8349emds.h.
1544 Enables the driver for the SPI controllers on i.MX and MXC
1545 SoCs. Currently only i.MX31 is supported.
1547 - FPGA Support: CONFIG_FPGA
1549 Enables FPGA subsystem.
1551 CONFIG_FPGA_<vendor>
1553 Enables support for specific chip vendors.
1556 CONFIG_FPGA_<family>
1558 Enables support for FPGA family.
1559 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1563 Specify the number of FPGA devices to support.
1565 CONFIG_SYS_FPGA_PROG_FEEDBACK
1567 Enable printing of hash marks during FPGA configuration.
1569 CONFIG_SYS_FPGA_CHECK_BUSY
1571 Enable checks on FPGA configuration interface busy
1572 status by the configuration function. This option
1573 will require a board or device specific function to
1578 If defined, a function that provides delays in the FPGA
1579 configuration driver.
1581 CONFIG_SYS_FPGA_CHECK_CTRLC
1582 Allow Control-C to interrupt FPGA configuration
1584 CONFIG_SYS_FPGA_CHECK_ERROR
1586 Check for configuration errors during FPGA bitfile
1587 loading. For example, abort during Virtex II
1588 configuration if the INIT_B line goes low (which
1589 indicated a CRC error).
1591 CONFIG_SYS_FPGA_WAIT_INIT
1593 Maximum time to wait for the INIT_B line to deassert
1594 after PROB_B has been deasserted during a Virtex II
1595 FPGA configuration sequence. The default time is 500
1598 CONFIG_SYS_FPGA_WAIT_BUSY
1600 Maximum time to wait for BUSY to deassert during
1601 Virtex II FPGA configuration. The default is 5 ms.
1603 CONFIG_SYS_FPGA_WAIT_CONFIG
1605 Time to wait after FPGA configuration. The default is
1608 - Configuration Management:
1611 If defined, this string will be added to the U-Boot
1612 version information (U_BOOT_VERSION)
1614 - Vendor Parameter Protection:
1616 U-Boot considers the values of the environment
1617 variables "serial#" (Board Serial Number) and
1618 "ethaddr" (Ethernet Address) to be parameters that
1619 are set once by the board vendor / manufacturer, and
1620 protects these variables from casual modification by
1621 the user. Once set, these variables are read-only,
1622 and write or delete attempts are rejected. You can
1623 change this behaviour:
1625 If CONFIG_ENV_OVERWRITE is #defined in your config
1626 file, the write protection for vendor parameters is
1627 completely disabled. Anybody can change or delete
1630 Alternatively, if you #define _both_ CONFIG_ETHADDR
1631 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1632 Ethernet address is installed in the environment,
1633 which can be changed exactly ONCE by the user. [The
1634 serial# is unaffected by this, i. e. it remains
1640 Define this variable to enable the reservation of
1641 "protected RAM", i. e. RAM which is not overwritten
1642 by U-Boot. Define CONFIG_PRAM to hold the number of
1643 kB you want to reserve for pRAM. You can overwrite
1644 this default value by defining an environment
1645 variable "pram" to the number of kB you want to
1646 reserve. Note that the board info structure will
1647 still show the full amount of RAM. If pRAM is
1648 reserved, a new environment variable "mem" will
1649 automatically be defined to hold the amount of
1650 remaining RAM in a form that can be passed as boot
1651 argument to Linux, for instance like that:
1653 setenv bootargs ... mem=\${mem}
1656 This way you can tell Linux not to use this memory,
1657 either, which results in a memory region that will
1658 not be affected by reboots.
1660 *WARNING* If your board configuration uses automatic
1661 detection of the RAM size, you must make sure that
1662 this memory test is non-destructive. So far, the
1663 following board configurations are known to be
1666 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1667 HERMES, IP860, RPXlite, LWMON, LANTEC,
1668 PCU_E, FLAGADM, TQM8260
1673 Define this variable to stop the system in case of a
1674 fatal error, so that you have to reset it manually.
1675 This is probably NOT a good idea for an embedded
1676 system where you want the system to reboot
1677 automatically as fast as possible, but it may be
1678 useful during development since you can try to debug
1679 the conditions that lead to the situation.
1681 CONFIG_NET_RETRY_COUNT
1683 This variable defines the number of retries for
1684 network operations like ARP, RARP, TFTP, or BOOTP
1685 before giving up the operation. If not defined, a
1686 default value of 5 is used.
1690 Timeout waiting for an ARP reply in milliseconds.
1692 - Command Interpreter:
1693 CONFIG_AUTO_COMPLETE
1695 Enable auto completion of commands using TAB.
1697 Note that this feature has NOT been implemented yet
1698 for the "hush" shell.
1701 CONFIG_SYS_HUSH_PARSER
1703 Define this variable to enable the "hush" shell (from
1704 Busybox) as command line interpreter, thus enabling
1705 powerful command line syntax like
1706 if...then...else...fi conditionals or `&&' and '||'
1707 constructs ("shell scripts").
1709 If undefined, you get the old, much simpler behaviour
1710 with a somewhat smaller memory footprint.
1713 CONFIG_SYS_PROMPT_HUSH_PS2
1715 This defines the secondary prompt string, which is
1716 printed when the command interpreter needs more input
1717 to complete a command. Usually "> ".
1721 In the current implementation, the local variables
1722 space and global environment variables space are
1723 separated. Local variables are those you define by
1724 simply typing `name=value'. To access a local
1725 variable later on, you have write `$name' or
1726 `${name}'; to execute the contents of a variable
1727 directly type `$name' at the command prompt.
1729 Global environment variables are those you use
1730 setenv/printenv to work with. To run a command stored
1731 in such a variable, you need to use the run command,
1732 and you must not use the '$' sign to access them.
1734 To store commands and special characters in a
1735 variable, please use double quotation marks
1736 surrounding the whole text of the variable, instead
1737 of the backslashes before semicolons and special
1740 - Commandline Editing and History:
1741 CONFIG_CMDLINE_EDITING
1743 Enable editing and History functions for interactive
1744 commandline input operations
1746 - Default Environment:
1747 CONFIG_EXTRA_ENV_SETTINGS
1749 Define this to contain any number of null terminated
1750 strings (variable = value pairs) that will be part of
1751 the default environment compiled into the boot image.
1753 For example, place something like this in your
1754 board's config file:
1756 #define CONFIG_EXTRA_ENV_SETTINGS \
1760 Warning: This method is based on knowledge about the
1761 internal format how the environment is stored by the
1762 U-Boot code. This is NOT an official, exported
1763 interface! Although it is unlikely that this format
1764 will change soon, there is no guarantee either.
1765 You better know what you are doing here.
1767 Note: overly (ab)use of the default environment is
1768 discouraged. Make sure to check other ways to preset
1769 the environment like the autoscript function or the
1772 - DataFlash Support:
1773 CONFIG_HAS_DATAFLASH
1775 Defining this option enables DataFlash features and
1776 allows to read/write in Dataflash via the standard
1779 - SystemACE Support:
1782 Adding this option adds support for Xilinx SystemACE
1783 chips attached via some sort of local bus. The address
1784 of the chip must also be defined in the
1785 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1787 #define CONFIG_SYSTEMACE
1788 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1790 When SystemACE support is added, the "ace" device type
1791 becomes available to the fat commands, i.e. fatls.
1793 - TFTP Fixed UDP Port:
1796 If this is defined, the environment variable tftpsrcp
1797 is used to supply the TFTP UDP source port value.
1798 If tftpsrcp isn't defined, the normal pseudo-random port
1799 number generator is used.
1801 Also, the environment variable tftpdstp is used to supply
1802 the TFTP UDP destination port value. If tftpdstp isn't
1803 defined, the normal port 69 is used.
1805 The purpose for tftpsrcp is to allow a TFTP server to
1806 blindly start the TFTP transfer using the pre-configured
1807 target IP address and UDP port. This has the effect of
1808 "punching through" the (Windows XP) firewall, allowing
1809 the remainder of the TFTP transfer to proceed normally.
1810 A better solution is to properly configure the firewall,
1811 but sometimes that is not allowed.
1813 - Show boot progress:
1814 CONFIG_SHOW_BOOT_PROGRESS
1816 Defining this option allows to add some board-
1817 specific code (calling a user-provided function
1818 "show_boot_progress(int)") that enables you to show
1819 the system's boot progress on some display (for
1820 example, some LED's) on your board. At the moment,
1821 the following checkpoints are implemented:
1823 - Automatic software updates via TFTP server
1825 CONFIG_UPDATE_TFTP_CNT_MAX
1826 CONFIG_UPDATE_TFTP_MSEC_MAX
1828 These options enable and control the auto-update feature;
1829 for a more detailed description refer to doc/README.update.
1831 Legacy uImage format:
1834 1 common/cmd_bootm.c before attempting to boot an image
1835 -1 common/cmd_bootm.c Image header has bad magic number
1836 2 common/cmd_bootm.c Image header has correct magic number
1837 -2 common/cmd_bootm.c Image header has bad checksum
1838 3 common/cmd_bootm.c Image header has correct checksum
1839 -3 common/cmd_bootm.c Image data has bad checksum
1840 4 common/cmd_bootm.c Image data has correct checksum
1841 -4 common/cmd_bootm.c Image is for unsupported architecture
1842 5 common/cmd_bootm.c Architecture check OK
1843 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1844 6 common/cmd_bootm.c Image Type check OK
1845 -6 common/cmd_bootm.c gunzip uncompression error
1846 -7 common/cmd_bootm.c Unimplemented compression type
1847 7 common/cmd_bootm.c Uncompression OK
1848 8 common/cmd_bootm.c No uncompress/copy overwrite error
1849 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1851 9 common/image.c Start initial ramdisk verification
1852 -10 common/image.c Ramdisk header has bad magic number
1853 -11 common/image.c Ramdisk header has bad checksum
1854 10 common/image.c Ramdisk header is OK
1855 -12 common/image.c Ramdisk data has bad checksum
1856 11 common/image.c Ramdisk data has correct checksum
1857 12 common/image.c Ramdisk verification complete, start loading
1858 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1859 13 common/image.c Start multifile image verification
1860 14 common/image.c No initial ramdisk, no multifile, continue.
1862 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1864 -30 lib_ppc/board.c Fatal error, hang the system
1865 -31 post/post.c POST test failed, detected by post_output_backlog()
1866 -32 post/post.c POST test failed, detected by post_run_single()
1868 34 common/cmd_doc.c before loading a Image from a DOC device
1869 -35 common/cmd_doc.c Bad usage of "doc" command
1870 35 common/cmd_doc.c correct usage of "doc" command
1871 -36 common/cmd_doc.c No boot device
1872 36 common/cmd_doc.c correct boot device
1873 -37 common/cmd_doc.c Unknown Chip ID on boot device
1874 37 common/cmd_doc.c correct chip ID found, device available
1875 -38 common/cmd_doc.c Read Error on boot device
1876 38 common/cmd_doc.c reading Image header from DOC device OK
1877 -39 common/cmd_doc.c Image header has bad magic number
1878 39 common/cmd_doc.c Image header has correct magic number
1879 -40 common/cmd_doc.c Error reading Image from DOC device
1880 40 common/cmd_doc.c Image header has correct magic number
1881 41 common/cmd_ide.c before loading a Image from a IDE device
1882 -42 common/cmd_ide.c Bad usage of "ide" command
1883 42 common/cmd_ide.c correct usage of "ide" command
1884 -43 common/cmd_ide.c No boot device
1885 43 common/cmd_ide.c boot device found
1886 -44 common/cmd_ide.c Device not available
1887 44 common/cmd_ide.c Device available
1888 -45 common/cmd_ide.c wrong partition selected
1889 45 common/cmd_ide.c partition selected
1890 -46 common/cmd_ide.c Unknown partition table
1891 46 common/cmd_ide.c valid partition table found
1892 -47 common/cmd_ide.c Invalid partition type
1893 47 common/cmd_ide.c correct partition type
1894 -48 common/cmd_ide.c Error reading Image Header on boot device
1895 48 common/cmd_ide.c reading Image Header from IDE device OK
1896 -49 common/cmd_ide.c Image header has bad magic number
1897 49 common/cmd_ide.c Image header has correct magic number
1898 -50 common/cmd_ide.c Image header has bad checksum
1899 50 common/cmd_ide.c Image header has correct checksum
1900 -51 common/cmd_ide.c Error reading Image from IDE device
1901 51 common/cmd_ide.c reading Image from IDE device OK
1902 52 common/cmd_nand.c before loading a Image from a NAND device
1903 -53 common/cmd_nand.c Bad usage of "nand" command
1904 53 common/cmd_nand.c correct usage of "nand" command
1905 -54 common/cmd_nand.c No boot device
1906 54 common/cmd_nand.c boot device found
1907 -55 common/cmd_nand.c Unknown Chip ID on boot device
1908 55 common/cmd_nand.c correct chip ID found, device available
1909 -56 common/cmd_nand.c Error reading Image Header on boot device
1910 56 common/cmd_nand.c reading Image Header from NAND device OK
1911 -57 common/cmd_nand.c Image header has bad magic number
1912 57 common/cmd_nand.c Image header has correct magic number
1913 -58 common/cmd_nand.c Error reading Image from NAND device
1914 58 common/cmd_nand.c reading Image from NAND device OK
1916 -60 common/env_common.c Environment has a bad CRC, using default
1918 64 net/eth.c starting with Ethernet configuration.
1919 -64 net/eth.c no Ethernet found.
1920 65 net/eth.c Ethernet found.
1922 -80 common/cmd_net.c usage wrong
1923 80 common/cmd_net.c before calling NetLoop()
1924 -81 common/cmd_net.c some error in NetLoop() occurred
1925 81 common/cmd_net.c NetLoop() back without error
1926 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1927 82 common/cmd_net.c trying automatic boot
1928 83 common/cmd_net.c running autoscript
1929 -83 common/cmd_net.c some error in automatic boot or autoscript
1930 84 common/cmd_net.c end without errors
1935 100 common/cmd_bootm.c Kernel FIT Image has correct format
1936 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1937 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1938 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1939 102 common/cmd_bootm.c Kernel unit name specified
1940 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1941 103 common/cmd_bootm.c Found configuration node
1942 104 common/cmd_bootm.c Got kernel subimage node offset
1943 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1944 105 common/cmd_bootm.c Kernel subimage hash verification OK
1945 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1946 106 common/cmd_bootm.c Architecture check OK
1947 -106 common/cmd_bootm.c Kernel subimage has wrong type
1948 107 common/cmd_bootm.c Kernel subimage type OK
1949 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1950 108 common/cmd_bootm.c Got kernel subimage data/size
1951 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1952 -109 common/cmd_bootm.c Can't get kernel subimage type
1953 -110 common/cmd_bootm.c Can't get kernel subimage comp
1954 -111 common/cmd_bootm.c Can't get kernel subimage os
1955 -112 common/cmd_bootm.c Can't get kernel subimage load address
1956 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1958 120 common/image.c Start initial ramdisk verification
1959 -120 common/image.c Ramdisk FIT image has incorrect format
1960 121 common/image.c Ramdisk FIT image has correct format
1961 122 common/image.c No ramdisk subimage unit name, using configuration
1962 -122 common/image.c Can't get configuration for ramdisk subimage
1963 123 common/image.c Ramdisk unit name specified
1964 -124 common/image.c Can't get ramdisk subimage node offset
1965 125 common/image.c Got ramdisk subimage node offset
1966 -125 common/image.c Ramdisk subimage hash verification failed
1967 126 common/image.c Ramdisk subimage hash verification OK
1968 -126 common/image.c Ramdisk subimage for unsupported architecture
1969 127 common/image.c Architecture check OK
1970 -127 common/image.c Can't get ramdisk subimage data/size
1971 128 common/image.c Got ramdisk subimage data/size
1972 129 common/image.c Can't get ramdisk load address
1973 -129 common/image.c Got ramdisk load address
1975 -130 common/cmd_doc.c Incorrect FIT image format
1976 131 common/cmd_doc.c FIT image format OK
1978 -140 common/cmd_ide.c Incorrect FIT image format
1979 141 common/cmd_ide.c FIT image format OK
1981 -150 common/cmd_nand.c Incorrect FIT image format
1982 151 common/cmd_nand.c FIT image format OK
1988 [so far only for SMDK2400 and TRAB boards]
1990 - Modem support enable:
1991 CONFIG_MODEM_SUPPORT
1993 - RTS/CTS Flow control enable:
1996 - Modem debug support:
1997 CONFIG_MODEM_SUPPORT_DEBUG
1999 Enables debugging stuff (char screen[1024], dbg())
2000 for modem support. Useful only with BDI2000.
2002 - Interrupt support (PPC):
2004 There are common interrupt_init() and timer_interrupt()
2005 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2006 for CPU specific initialization. interrupt_init_cpu()
2007 should set decrementer_count to appropriate value. If
2008 CPU resets decrementer automatically after interrupt
2009 (ppc4xx) it should set decrementer_count to zero.
2010 timer_interrupt() calls timer_interrupt_cpu() for CPU
2011 specific handling. If board has watchdog / status_led
2012 / other_activity_monitor it works automatically from
2013 general timer_interrupt().
2017 In the target system modem support is enabled when a
2018 specific key (key combination) is pressed during
2019 power-on. Otherwise U-Boot will boot normally
2020 (autoboot). The key_pressed() function is called from
2021 board_init(). Currently key_pressed() is a dummy
2022 function, returning 1 and thus enabling modem
2025 If there are no modem init strings in the
2026 environment, U-Boot proceed to autoboot; the
2027 previous output (banner, info printfs) will be
2030 See also: doc/README.Modem
2033 Configuration Settings:
2034 -----------------------
2036 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2037 undefine this when you're short of memory.
2039 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2040 prompt for user input.
2042 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2044 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2046 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2048 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2049 the application (usually a Linux kernel) when it is
2052 - CONFIG_SYS_BAUDRATE_TABLE:
2053 List of legal baudrate settings for this board.
2055 - CONFIG_SYS_CONSOLE_INFO_QUIET
2056 Suppress display of console information at boot.
2058 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2059 If the board specific function
2060 extern int overwrite_console (void);
2061 returns 1, the stdin, stderr and stdout are switched to the
2062 serial port, else the settings in the environment are used.
2064 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2065 Enable the call to overwrite_console().
2067 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2068 Enable overwrite of previous console environment settings.
2070 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2071 Begin and End addresses of the area used by the
2074 - CONFIG_SYS_ALT_MEMTEST:
2075 Enable an alternate, more extensive memory test.
2077 - CONFIG_SYS_MEMTEST_SCRATCH:
2078 Scratch address used by the alternate memory test
2079 You only need to set this if address zero isn't writeable
2081 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2082 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2083 this specified memory area will get subtracted from the top
2084 (end) of RAM and won't get "touched" at all by U-Boot. By
2085 fixing up gd->ram_size the Linux kernel should gets passed
2086 the now "corrected" memory size and won't touch it either.
2087 This should work for arch/ppc and arch/powerpc. Only Linux
2088 board ports in arch/powerpc with bootwrapper support that
2089 recalculate the memory size from the SDRAM controller setup
2090 will have to get fixed in Linux additionally.
2092 This option can be used as a workaround for the 440EPx/GRx
2093 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2096 WARNING: Please make sure that this value is a multiple of
2097 the Linux page size (normally 4k). If this is not the case,
2098 then the end address of the Linux memory will be located at a
2099 non page size aligned address and this could cause major
2102 - CONFIG_SYS_TFTP_LOADADDR:
2103 Default load address for network file downloads
2105 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2106 Enable temporary baudrate change while serial download
2108 - CONFIG_SYS_SDRAM_BASE:
2109 Physical start address of SDRAM. _Must_ be 0 here.
2111 - CONFIG_SYS_MBIO_BASE:
2112 Physical start address of Motherboard I/O (if using a
2115 - CONFIG_SYS_FLASH_BASE:
2116 Physical start address of Flash memory.
2118 - CONFIG_SYS_MONITOR_BASE:
2119 Physical start address of boot monitor code (set by
2120 make config files to be same as the text base address
2121 (TEXT_BASE) used when linking) - same as
2122 CONFIG_SYS_FLASH_BASE when booting from flash.
2124 - CONFIG_SYS_MONITOR_LEN:
2125 Size of memory reserved for monitor code, used to
2126 determine _at_compile_time_ (!) if the environment is
2127 embedded within the U-Boot image, or in a separate
2130 - CONFIG_SYS_MALLOC_LEN:
2131 Size of DRAM reserved for malloc() use.
2133 - CONFIG_SYS_BOOTM_LEN:
2134 Normally compressed uImages are limited to an
2135 uncompressed size of 8 MBytes. If this is not enough,
2136 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2137 to adjust this setting to your needs.
2139 - CONFIG_SYS_BOOTMAPSZ:
2140 Maximum size of memory mapped by the startup code of
2141 the Linux kernel; all data that must be processed by
2142 the Linux kernel (bd_info, boot arguments, FDT blob if
2143 used) must be put below this limit, unless "bootm_low"
2144 enviroment variable is defined and non-zero. In such case
2145 all data for the Linux kernel must be between "bootm_low"
2146 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2148 - CONFIG_SYS_MAX_FLASH_BANKS:
2149 Max number of Flash memory banks
2151 - CONFIG_SYS_MAX_FLASH_SECT:
2152 Max number of sectors on a Flash chip
2154 - CONFIG_SYS_FLASH_ERASE_TOUT:
2155 Timeout for Flash erase operations (in ms)
2157 - CONFIG_SYS_FLASH_WRITE_TOUT:
2158 Timeout for Flash write operations (in ms)
2160 - CONFIG_SYS_FLASH_LOCK_TOUT
2161 Timeout for Flash set sector lock bit operation (in ms)
2163 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2164 Timeout for Flash clear lock bits operation (in ms)
2166 - CONFIG_SYS_FLASH_PROTECTION
2167 If defined, hardware flash sectors protection is used
2168 instead of U-Boot software protection.
2170 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2172 Enable TFTP transfers directly to flash memory;
2173 without this option such a download has to be
2174 performed in two steps: (1) download to RAM, and (2)
2175 copy from RAM to flash.
2177 The two-step approach is usually more reliable, since
2178 you can check if the download worked before you erase
2179 the flash, but in some situations (when system RAM is
2180 too limited to allow for a temporary copy of the
2181 downloaded image) this option may be very useful.
2183 - CONFIG_SYS_FLASH_CFI:
2184 Define if the flash driver uses extra elements in the
2185 common flash structure for storing flash geometry.
2187 - CONFIG_FLASH_CFI_DRIVER
2188 This option also enables the building of the cfi_flash driver
2189 in the drivers directory
2191 - CONFIG_FLASH_CFI_MTD
2192 This option enables the building of the cfi_mtd driver
2193 in the drivers directory. The driver exports CFI flash
2196 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2197 Use buffered writes to flash.
2199 - CONFIG_FLASH_SPANSION_S29WS_N
2200 s29ws-n MirrorBit flash has non-standard addresses for buffered
2203 - CONFIG_SYS_FLASH_QUIET_TEST
2204 If this option is defined, the common CFI flash doesn't
2205 print it's warning upon not recognized FLASH banks. This
2206 is useful, if some of the configured banks are only
2207 optionally available.
2209 - CONFIG_FLASH_SHOW_PROGRESS
2210 If defined (must be an integer), print out countdown
2211 digits and dots. Recommended value: 45 (9..1) for 80
2212 column displays, 15 (3..1) for 40 column displays.
2214 - CONFIG_SYS_RX_ETH_BUFFER:
2215 Defines the number of Ethernet receive buffers. On some
2216 Ethernet controllers it is recommended to set this value
2217 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2218 buffers can be full shortly after enabling the interface
2219 on high Ethernet traffic.
2220 Defaults to 4 if not defined.
2222 The following definitions that deal with the placement and management
2223 of environment data (variable area); in general, we support the
2224 following configurations:
2226 - CONFIG_ENV_IS_IN_FLASH:
2228 Define this if the environment is in flash memory.
2230 a) The environment occupies one whole flash sector, which is
2231 "embedded" in the text segment with the U-Boot code. This
2232 happens usually with "bottom boot sector" or "top boot
2233 sector" type flash chips, which have several smaller
2234 sectors at the start or the end. For instance, such a
2235 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2236 such a case you would place the environment in one of the
2237 4 kB sectors - with U-Boot code before and after it. With
2238 "top boot sector" type flash chips, you would put the
2239 environment in one of the last sectors, leaving a gap
2240 between U-Boot and the environment.
2242 - CONFIG_ENV_OFFSET:
2244 Offset of environment data (variable area) to the
2245 beginning of flash memory; for instance, with bottom boot
2246 type flash chips the second sector can be used: the offset
2247 for this sector is given here.
2249 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2253 This is just another way to specify the start address of
2254 the flash sector containing the environment (instead of
2257 - CONFIG_ENV_SECT_SIZE:
2259 Size of the sector containing the environment.
2262 b) Sometimes flash chips have few, equal sized, BIG sectors.
2263 In such a case you don't want to spend a whole sector for
2268 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2269 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2270 of this flash sector for the environment. This saves
2271 memory for the RAM copy of the environment.
2273 It may also save flash memory if you decide to use this
2274 when your environment is "embedded" within U-Boot code,
2275 since then the remainder of the flash sector could be used
2276 for U-Boot code. It should be pointed out that this is
2277 STRONGLY DISCOURAGED from a robustness point of view:
2278 updating the environment in flash makes it always
2279 necessary to erase the WHOLE sector. If something goes
2280 wrong before the contents has been restored from a copy in
2281 RAM, your target system will be dead.
2283 - CONFIG_ENV_ADDR_REDUND
2284 CONFIG_ENV_SIZE_REDUND
2286 These settings describe a second storage area used to hold
2287 a redundant copy of the environment data, so that there is
2288 a valid backup copy in case there is a power failure during
2289 a "saveenv" operation.
2291 BE CAREFUL! Any changes to the flash layout, and some changes to the
2292 source code will make it necessary to adapt <board>/u-boot.lds*
2296 - CONFIG_ENV_IS_IN_NVRAM:
2298 Define this if you have some non-volatile memory device
2299 (NVRAM, battery buffered SRAM) which you want to use for the
2305 These two #defines are used to determine the memory area you
2306 want to use for environment. It is assumed that this memory
2307 can just be read and written to, without any special
2310 BE CAREFUL! The first access to the environment happens quite early
2311 in U-Boot initalization (when we try to get the setting of for the
2312 console baudrate). You *MUST* have mapped your NVRAM area then, or
2315 Please note that even with NVRAM we still use a copy of the
2316 environment in RAM: we could work on NVRAM directly, but we want to
2317 keep settings there always unmodified except somebody uses "saveenv"
2318 to save the current settings.
2321 - CONFIG_ENV_IS_IN_EEPROM:
2323 Use this if you have an EEPROM or similar serial access
2324 device and a driver for it.
2326 - CONFIG_ENV_OFFSET:
2329 These two #defines specify the offset and size of the
2330 environment area within the total memory of your EEPROM.
2332 - CONFIG_SYS_I2C_EEPROM_ADDR:
2333 If defined, specified the chip address of the EEPROM device.
2334 The default address is zero.
2336 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2337 If defined, the number of bits used to address bytes in a
2338 single page in the EEPROM device. A 64 byte page, for example
2339 would require six bits.
2341 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2342 If defined, the number of milliseconds to delay between
2343 page writes. The default is zero milliseconds.
2345 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2346 The length in bytes of the EEPROM memory array address. Note
2347 that this is NOT the chip address length!
2349 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2350 EEPROM chips that implement "address overflow" are ones
2351 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2352 address and the extra bits end up in the "chip address" bit
2353 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2356 Note that we consider the length of the address field to
2357 still be one byte because the extra address bits are hidden
2358 in the chip address.
2360 - CONFIG_SYS_EEPROM_SIZE:
2361 The size in bytes of the EEPROM device.
2364 - CONFIG_ENV_IS_IN_DATAFLASH:
2366 Define this if you have a DataFlash memory device which you
2367 want to use for the environment.
2369 - CONFIG_ENV_OFFSET:
2373 These three #defines specify the offset and size of the
2374 environment area within the total memory of your DataFlash placed
2375 at the specified address.
2377 - CONFIG_ENV_IS_IN_NAND:
2379 Define this if you have a NAND device which you want to use
2380 for the environment.
2382 - CONFIG_ENV_OFFSET:
2385 These two #defines specify the offset and size of the environment
2386 area within the first NAND device.
2388 - CONFIG_ENV_OFFSET_REDUND
2390 This setting describes a second storage area of CONFIG_ENV_SIZE
2391 size used to hold a redundant copy of the environment data,
2392 so that there is a valid backup copy in case there is a
2393 power failure during a "saveenv" operation.
2395 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2396 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2397 the NAND devices block size.
2399 - CONFIG_SYS_SPI_INIT_OFFSET
2401 Defines offset to the initial SPI buffer area in DPRAM. The
2402 area is used at an early stage (ROM part) if the environment
2403 is configured to reside in the SPI EEPROM: We need a 520 byte
2404 scratch DPRAM area. It is used between the two initialization
2405 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2406 to be a good choice since it makes it far enough from the
2407 start of the data area as well as from the stack pointer.
2409 Please note that the environment is read-only until the monitor
2410 has been relocated to RAM and a RAM copy of the environment has been
2411 created; also, when using EEPROM you will have to use getenv_r()
2412 until then to read environment variables.
2414 The environment is protected by a CRC32 checksum. Before the monitor
2415 is relocated into RAM, as a result of a bad CRC you will be working
2416 with the compiled-in default environment - *silently*!!! [This is
2417 necessary, because the first environment variable we need is the
2418 "baudrate" setting for the console - if we have a bad CRC, we don't
2419 have any device yet where we could complain.]
2421 Note: once the monitor has been relocated, then it will complain if
2422 the default environment is used; a new CRC is computed as soon as you
2423 use the "saveenv" command to store a valid environment.
2425 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2426 Echo the inverted Ethernet link state to the fault LED.
2428 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2429 also needs to be defined.
2431 - CONFIG_SYS_FAULT_MII_ADDR:
2432 MII address of the PHY to check for the Ethernet link state.
2434 - CONFIG_SYS_64BIT_VSPRINTF:
2435 Makes vsprintf (and all *printf functions) support printing
2436 of 64bit values by using the L quantifier
2438 - CONFIG_SYS_64BIT_STRTOUL:
2439 Adds simple_strtoull that returns a 64bit value
2441 Low Level (hardware related) configuration options:
2442 ---------------------------------------------------
2444 - CONFIG_SYS_CACHELINE_SIZE:
2445 Cache Line Size of the CPU.
2447 - CONFIG_SYS_DEFAULT_IMMR:
2448 Default address of the IMMR after system reset.
2450 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2451 and RPXsuper) to be able to adjust the position of
2452 the IMMR register after a reset.
2454 - Floppy Disk Support:
2455 CONFIG_SYS_FDC_DRIVE_NUMBER
2457 the default drive number (default value 0)
2459 CONFIG_SYS_ISA_IO_STRIDE
2461 defines the spacing between FDC chipset registers
2464 CONFIG_SYS_ISA_IO_OFFSET
2466 defines the offset of register from address. It
2467 depends on which part of the data bus is connected to
2468 the FDC chipset. (default value 0)
2470 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2471 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2474 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2475 fdc_hw_init() is called at the beginning of the FDC
2476 setup. fdc_hw_init() must be provided by the board
2477 source code. It is used to make hardware dependant
2480 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2481 DO NOT CHANGE unless you know exactly what you're
2482 doing! (11-4) [MPC8xx/82xx systems only]
2484 - CONFIG_SYS_INIT_RAM_ADDR:
2486 Start address of memory area that can be used for
2487 initial data and stack; please note that this must be
2488 writable memory that is working WITHOUT special
2489 initialization, i. e. you CANNOT use normal RAM which
2490 will become available only after programming the
2491 memory controller and running certain initialization
2494 U-Boot uses the following memory types:
2495 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2496 - MPC824X: data cache
2497 - PPC4xx: data cache
2499 - CONFIG_SYS_GBL_DATA_OFFSET:
2501 Offset of the initial data structure in the memory
2502 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2503 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2504 data is located at the end of the available space
2505 (sometimes written as (CONFIG_SYS_INIT_RAM_END -
2506 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2507 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2508 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2511 On the MPC824X (or other systems that use the data
2512 cache for initial memory) the address chosen for
2513 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2514 point to an otherwise UNUSED address space between
2515 the top of RAM and the start of the PCI space.
2517 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2519 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2521 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2523 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2525 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2527 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2529 - CONFIG_SYS_OR_TIMING_SDRAM:
2532 - CONFIG_SYS_MAMR_PTA:
2533 periodic timer for refresh
2535 - CONFIG_SYS_DER: Debug Event Register (37-47)
2537 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2538 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2539 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2540 CONFIG_SYS_BR1_PRELIM:
2541 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2543 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2544 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2545 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2546 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2548 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2549 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2550 Machine Mode Register and Memory Periodic Timer
2551 Prescaler definitions (SDRAM timing)
2553 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2554 enable I2C microcode relocation patch (MPC8xx);
2555 define relocation offset in DPRAM [DSP2]
2557 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2558 enable SMC microcode relocation patch (MPC8xx);
2559 define relocation offset in DPRAM [SMC1]
2561 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2562 enable SPI microcode relocation patch (MPC8xx);
2563 define relocation offset in DPRAM [SCC4]
2565 - CONFIG_SYS_USE_OSCCLK:
2566 Use OSCM clock mode on MBX8xx board. Be careful,
2567 wrong setting might damage your board. Read
2568 doc/README.MBX before setting this variable!
2570 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2571 Offset of the bootmode word in DPRAM used by post
2572 (Power On Self Tests). This definition overrides
2573 #define'd default value in commproc.h resp.
2576 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2577 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2578 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2579 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2580 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2581 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2582 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2583 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2584 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2587 Get DDR timing information from an I2C EEPROM. Common
2588 with pluggable memory modules such as SODIMMs
2591 I2C address of the SPD EEPROM
2593 - CONFIG_SYS_SPD_BUS_NUM
2594 If SPD EEPROM is on an I2C bus other than the first
2595 one, specify here. Note that the value must resolve
2596 to something your driver can deal with.
2598 - CONFIG_SYS_83XX_DDR_USES_CS0
2599 Only for 83xx systems. If specified, then DDR should
2600 be configured using CS0 and CS1 instead of CS2 and CS3.
2602 - CONFIG_SYS_83XX_DDR_USES_CS0
2603 Only for 83xx systems. If specified, then DDR should
2604 be configured using CS0 and CS1 instead of CS2 and CS3.
2606 - CONFIG_ETHER_ON_FEC[12]
2607 Define to enable FEC[12] on a 8xx series processor.
2609 - CONFIG_FEC[12]_PHY
2610 Define to the hardcoded PHY address which corresponds
2611 to the given FEC; i. e.
2612 #define CONFIG_FEC1_PHY 4
2613 means that the PHY with address 4 is connected to FEC1
2615 When set to -1, means to probe for first available.
2617 - CONFIG_FEC[12]_PHY_NORXERR
2618 The PHY does not have a RXERR line (RMII only).
2619 (so program the FEC to ignore it).
2622 Enable RMII mode for all FECs.
2623 Note that this is a global option, we can't
2624 have one FEC in standard MII mode and another in RMII mode.
2626 - CONFIG_CRC32_VERIFY
2627 Add a verify option to the crc32 command.
2630 => crc32 -v <address> <count> <crc32>
2632 Where address/count indicate a memory area
2633 and crc32 is the correct crc32 which the
2637 Add the "loopw" memory command. This only takes effect if
2638 the memory commands are activated globally (CONFIG_CMD_MEM).
2641 Add the "mdc" and "mwc" memory commands. These are cyclic
2646 This command will print 4 bytes (10,11,12,13) each 500 ms.
2648 => mwc.l 100 12345678 10
2649 This command will write 12345678 to address 100 all 10 ms.
2651 This only takes effect if the memory commands are activated
2652 globally (CONFIG_CMD_MEM).
2654 - CONFIG_SKIP_LOWLEVEL_INIT
2655 - CONFIG_SKIP_RELOCATE_UBOOT
2657 [ARM only] If these variables are defined, then
2658 certain low level initializations (like setting up
2659 the memory controller) are omitted and/or U-Boot does
2660 not relocate itself into RAM.
2661 Normally these variables MUST NOT be defined. The
2662 only exception is when U-Boot is loaded (to RAM) by
2663 some other boot loader or by a debugger which
2664 performs these initializations itself.
2667 Building the Software:
2668 ======================
2670 Building U-Boot has been tested in several native build environments
2671 and in many different cross environments. Of course we cannot support
2672 all possibly existing versions of cross development tools in all
2673 (potentially obsolete) versions. In case of tool chain problems we
2674 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2675 which is extensively used to build and test U-Boot.
2677 If you are not using a native environment, it is assumed that you
2678 have GNU cross compiling tools available in your path. In this case,
2679 you must set the environment variable CROSS_COMPILE in your shell.
2680 Note that no changes to the Makefile or any other source files are
2681 necessary. For example using the ELDK on a 4xx CPU, please enter:
2683 $ CROSS_COMPILE=ppc_4xx-
2684 $ export CROSS_COMPILE
2686 U-Boot is intended to be simple to build. After installing the
2687 sources you must configure U-Boot for one specific board type. This
2692 where "NAME_config" is the name of one of the existing configu-
2693 rations; see the main Makefile for supported names.
2695 Note: for some board special configuration names may exist; check if
2696 additional information is available from the board vendor; for
2697 instance, the TQM823L systems are available without (standard)
2698 or with LCD support. You can select such additional "features"
2699 when choosing the configuration, i. e.
2702 - will configure for a plain TQM823L, i. e. no LCD support
2704 make TQM823L_LCD_config
2705 - will configure for a TQM823L with U-Boot console on LCD
2710 Finally, type "make all", and you should get some working U-Boot
2711 images ready for download to / installation on your system:
2713 - "u-boot.bin" is a raw binary image
2714 - "u-boot" is an image in ELF binary format
2715 - "u-boot.srec" is in Motorola S-Record format
2717 By default the build is performed locally and the objects are saved
2718 in the source directory. One of the two methods can be used to change
2719 this behavior and build U-Boot to some external directory:
2721 1. Add O= to the make command line invocations:
2723 make O=/tmp/build distclean
2724 make O=/tmp/build NAME_config
2725 make O=/tmp/build all
2727 2. Set environment variable BUILD_DIR to point to the desired location:
2729 export BUILD_DIR=/tmp/build
2734 Note that the command line "O=" setting overrides the BUILD_DIR environment
2738 Please be aware that the Makefiles assume you are using GNU make, so
2739 for instance on NetBSD you might need to use "gmake" instead of
2743 If the system board that you have is not listed, then you will need
2744 to port U-Boot to your hardware platform. To do this, follow these
2747 1. Add a new configuration option for your board to the toplevel
2748 "Makefile" and to the "MAKEALL" script, using the existing
2749 entries as examples. Note that here and at many other places
2750 boards and other names are listed in alphabetical sort order. Please
2752 2. Create a new directory to hold your board specific code. Add any
2753 files you need. In your board directory, you will need at least
2754 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2755 3. Create a new configuration file "include/configs/<board>.h" for
2757 3. If you're porting U-Boot to a new CPU, then also create a new
2758 directory to hold your CPU specific code. Add any files you need.
2759 4. Run "make <board>_config" with your new name.
2760 5. Type "make", and you should get a working "u-boot.srec" file
2761 to be installed on your target system.
2762 6. Debug and solve any problems that might arise.
2763 [Of course, this last step is much harder than it sounds.]
2766 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2767 ==============================================================
2769 If you have modified U-Boot sources (for instance added a new board
2770 or support for new devices, a new CPU, etc.) you are expected to
2771 provide feedback to the other developers. The feedback normally takes
2772 the form of a "patch", i. e. a context diff against a certain (latest
2773 official or latest in the git repository) version of U-Boot sources.
2775 But before you submit such a patch, please verify that your modifi-
2776 cation did not break existing code. At least make sure that *ALL* of
2777 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2778 just run the "MAKEALL" script, which will configure and build U-Boot
2779 for ALL supported system. Be warned, this will take a while. You can
2780 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2781 environment variable to the script, i. e. to use the ELDK cross tools
2784 CROSS_COMPILE=ppc_8xx- MAKEALL
2786 or to build on a native PowerPC system you can type
2788 CROSS_COMPILE=' ' MAKEALL
2790 When using the MAKEALL script, the default behaviour is to build
2791 U-Boot in the source directory. This location can be changed by
2792 setting the BUILD_DIR environment variable. Also, for each target
2793 built, the MAKEALL script saves two log files (<target>.ERR and
2794 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2795 location can be changed by setting the MAKEALL_LOGDIR environment
2796 variable. For example:
2798 export BUILD_DIR=/tmp/build
2799 export MAKEALL_LOGDIR=/tmp/log
2800 CROSS_COMPILE=ppc_8xx- MAKEALL
2802 With the above settings build objects are saved in the /tmp/build,
2803 log files are saved in the /tmp/log and the source tree remains clean
2804 during the whole build process.
2807 See also "U-Boot Porting Guide" below.
2810 Monitor Commands - Overview:
2811 ============================
2813 go - start application at address 'addr'
2814 run - run commands in an environment variable
2815 bootm - boot application image from memory
2816 bootp - boot image via network using BootP/TFTP protocol
2817 tftpboot- boot image via network using TFTP protocol
2818 and env variables "ipaddr" and "serverip"
2819 (and eventually "gatewayip")
2820 rarpboot- boot image via network using RARP/TFTP protocol
2821 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2822 loads - load S-Record file over serial line
2823 loadb - load binary file over serial line (kermit mode)
2825 mm - memory modify (auto-incrementing)
2826 nm - memory modify (constant address)
2827 mw - memory write (fill)
2829 cmp - memory compare
2830 crc32 - checksum calculation
2831 imd - i2c memory display
2832 imm - i2c memory modify (auto-incrementing)
2833 inm - i2c memory modify (constant address)
2834 imw - i2c memory write (fill)
2835 icrc32 - i2c checksum calculation
2836 iprobe - probe to discover valid I2C chip addresses
2837 iloop - infinite loop on address range
2838 isdram - print SDRAM configuration information
2839 sspi - SPI utility commands
2840 base - print or set address offset
2841 printenv- print environment variables
2842 setenv - set environment variables
2843 saveenv - save environment variables to persistent storage
2844 protect - enable or disable FLASH write protection
2845 erase - erase FLASH memory
2846 flinfo - print FLASH memory information
2847 bdinfo - print Board Info structure
2848 iminfo - print header information for application image
2849 coninfo - print console devices and informations
2850 ide - IDE sub-system
2851 loop - infinite loop on address range
2852 loopw - infinite write loop on address range
2853 mtest - simple RAM test
2854 icache - enable or disable instruction cache
2855 dcache - enable or disable data cache
2856 reset - Perform RESET of the CPU
2857 echo - echo args to console
2858 version - print monitor version
2859 help - print online help
2860 ? - alias for 'help'
2863 Monitor Commands - Detailed Description:
2864 ========================================
2868 For now: just type "help <command>".
2871 Environment Variables:
2872 ======================
2874 U-Boot supports user configuration using Environment Variables which
2875 can be made persistent by saving to Flash memory.
2877 Environment Variables are set using "setenv", printed using
2878 "printenv", and saved to Flash using "saveenv". Using "setenv"
2879 without a value can be used to delete a variable from the
2880 environment. As long as you don't save the environment you are
2881 working with an in-memory copy. In case the Flash area containing the
2882 environment is erased by accident, a default environment is provided.
2884 Some configuration options can be set using Environment Variables:
2886 baudrate - see CONFIG_BAUDRATE
2888 bootdelay - see CONFIG_BOOTDELAY
2890 bootcmd - see CONFIG_BOOTCOMMAND
2892 bootargs - Boot arguments when booting an RTOS image
2894 bootfile - Name of the image to load with TFTP
2896 bootm_low - Memory range available for image processing in the bootm
2897 command can be restricted. This variable is given as
2898 a hexadecimal number and defines lowest address allowed
2899 for use by the bootm command. See also "bootm_size"
2900 environment variable. Address defined by "bootm_low" is
2901 also the base of the initial memory mapping for the Linux
2902 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
2904 bootm_size - Memory range available for image processing in the bootm
2905 command can be restricted. This variable is given as
2906 a hexadecimal number and defines the size of the region
2907 allowed for use by the bootm command. See also "bootm_low"
2908 environment variable.
2910 updatefile - Location of the software update file on a TFTP server, used
2911 by the automatic software update feature. Please refer to
2912 documentation in doc/README.update for more details.
2914 autoload - if set to "no" (any string beginning with 'n'),
2915 "bootp" will just load perform a lookup of the
2916 configuration from the BOOTP server, but not try to
2917 load any image using TFTP
2919 autoscript - if set to "yes" commands like "loadb", "loady",
2920 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2921 to automatically run script images (by internally
2922 calling "autoscript").
2924 autoscript_uname - if script image is in a format (FIT) this
2925 variable is used to get script subimage unit name.
2927 autostart - if set to "yes", an image loaded using the "bootp",
2928 "rarpboot", "tftpboot" or "diskboot" commands will
2929 be automatically started (by internally calling
2932 If set to "no", a standalone image passed to the
2933 "bootm" command will be copied to the load address
2934 (and eventually uncompressed), but NOT be started.
2935 This can be used to load and uncompress arbitrary
2938 i2cfast - (PPC405GP|PPC405EP only)
2939 if set to 'y' configures Linux I2C driver for fast
2940 mode (400kHZ). This environment variable is used in
2941 initialization code. So, for changes to be effective
2942 it must be saved and board must be reset.
2944 initrd_high - restrict positioning of initrd images:
2945 If this variable is not set, initrd images will be
2946 copied to the highest possible address in RAM; this
2947 is usually what you want since it allows for
2948 maximum initrd size. If for some reason you want to
2949 make sure that the initrd image is loaded below the
2950 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
2951 variable to a value of "no" or "off" or "0".
2952 Alternatively, you can set it to a maximum upper
2953 address to use (U-Boot will still check that it
2954 does not overwrite the U-Boot stack and data).
2956 For instance, when you have a system with 16 MB
2957 RAM, and want to reserve 4 MB from use by Linux,
2958 you can do this by adding "mem=12M" to the value of
2959 the "bootargs" variable. However, now you must make
2960 sure that the initrd image is placed in the first
2961 12 MB as well - this can be done with
2963 setenv initrd_high 00c00000
2965 If you set initrd_high to 0xFFFFFFFF, this is an
2966 indication to U-Boot that all addresses are legal
2967 for the Linux kernel, including addresses in flash
2968 memory. In this case U-Boot will NOT COPY the
2969 ramdisk at all. This may be useful to reduce the
2970 boot time on your system, but requires that this
2971 feature is supported by your Linux kernel.
2973 ipaddr - IP address; needed for tftpboot command
2975 loadaddr - Default load address for commands like "bootp",
2976 "rarpboot", "tftpboot", "loadb" or "diskboot"
2978 loads_echo - see CONFIG_LOADS_ECHO
2980 serverip - TFTP server IP address; needed for tftpboot command
2982 bootretry - see CONFIG_BOOT_RETRY_TIME
2984 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2986 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2988 ethprime - When CONFIG_NET_MULTI is enabled controls which
2989 interface is used first.
2991 ethact - When CONFIG_NET_MULTI is enabled controls which
2992 interface is currently active. For example you
2993 can do the following
2995 => setenv ethact FEC ETHERNET
2996 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2997 => setenv ethact SCC ETHERNET
2998 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
3000 ethrotate - When set to "no" U-Boot does not go through all
3001 available network interfaces.
3002 It just stays at the currently selected interface.
3004 netretry - When set to "no" each network operation will
3005 either succeed or fail without retrying.
3006 When set to "once" the network operation will
3007 fail when all the available network interfaces
3008 are tried once without success.
3009 Useful on scripts which control the retry operation
3012 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
3013 if set load address for the NPE microcode
3015 tftpsrcport - If this is set, the value is used for TFTP's
3018 tftpdstport - If this is set, the value is used for TFTP's UDP
3019 destination port instead of the Well Know Port 69.
3021 vlan - When set to a value < 4095 the traffic over
3022 Ethernet is encapsulated/received over 802.1q
3025 The following environment variables may be used and automatically
3026 updated by the network boot commands ("bootp" and "rarpboot"),
3027 depending the information provided by your boot server:
3029 bootfile - see above
3030 dnsip - IP address of your Domain Name Server
3031 dnsip2 - IP address of your secondary Domain Name Server
3032 gatewayip - IP address of the Gateway (Router) to use
3033 hostname - Target hostname
3035 netmask - Subnet Mask
3036 rootpath - Pathname of the root filesystem on the NFS server
3037 serverip - see above
3040 There are two special Environment Variables:
3042 serial# - contains hardware identification information such
3043 as type string and/or serial number
3044 ethaddr - Ethernet address
3046 These variables can be set only once (usually during manufacturing of
3047 the board). U-Boot refuses to delete or overwrite these variables
3048 once they have been set once.
3051 Further special Environment Variables:
3053 ver - Contains the U-Boot version string as printed
3054 with the "version" command. This variable is
3055 readonly (see CONFIG_VERSION_VARIABLE).
3058 Please note that changes to some configuration parameters may take
3059 only effect after the next boot (yes, that's just like Windoze :-).
3062 Command Line Parsing:
3063 =====================
3065 There are two different command line parsers available with U-Boot:
3066 the old "simple" one, and the much more powerful "hush" shell:
3068 Old, simple command line parser:
3069 --------------------------------
3071 - supports environment variables (through setenv / saveenv commands)
3072 - several commands on one line, separated by ';'
3073 - variable substitution using "... ${name} ..." syntax
3074 - special characters ('$', ';') can be escaped by prefixing with '\',
3076 setenv bootcmd bootm \${address}
3077 - You can also escape text by enclosing in single apostrophes, for example:
3078 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3083 - similar to Bourne shell, with control structures like
3084 if...then...else...fi, for...do...done; while...do...done,
3085 until...do...done, ...
3086 - supports environment ("global") variables (through setenv / saveenv
3087 commands) and local shell variables (through standard shell syntax
3088 "name=value"); only environment variables can be used with "run"
3094 (1) If a command line (or an environment variable executed by a "run"
3095 command) contains several commands separated by semicolon, and
3096 one of these commands fails, then the remaining commands will be
3099 (2) If you execute several variables with one call to run (i. e.
3100 calling run with a list of variables as arguments), any failing
3101 command will cause "run" to terminate, i. e. the remaining
3102 variables are not executed.
3104 Note for Redundant Ethernet Interfaces:
3105 =======================================
3107 Some boards come with redundant Ethernet interfaces; U-Boot supports
3108 such configurations and is capable of automatic selection of a
3109 "working" interface when needed. MAC assignment works as follows:
3111 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3112 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3113 "eth1addr" (=>eth1), "eth2addr", ...
3115 If the network interface stores some valid MAC address (for instance
3116 in SROM), this is used as default address if there is NO correspon-
3117 ding setting in the environment; if the corresponding environment
3118 variable is set, this overrides the settings in the card; that means:
3120 o If the SROM has a valid MAC address, and there is no address in the
3121 environment, the SROM's address is used.
3123 o If there is no valid address in the SROM, and a definition in the
3124 environment exists, then the value from the environment variable is
3127 o If both the SROM and the environment contain a MAC address, and
3128 both addresses are the same, this MAC address is used.
3130 o If both the SROM and the environment contain a MAC address, and the
3131 addresses differ, the value from the environment is used and a
3134 o If neither SROM nor the environment contain a MAC address, an error
3141 U-Boot is capable of booting (and performing other auxiliary operations on)
3142 images in two formats:
3144 New uImage format (FIT)
3145 -----------------------
3147 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3148 to Flattened Device Tree). It allows the use of images with multiple
3149 components (several kernels, ramdisks, etc.), with contents protected by
3150 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3156 Old image format is based on binary files which can be basically anything,
3157 preceded by a special header; see the definitions in include/image.h for
3158 details; basically, the header defines the following image properties:
3160 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3161 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3162 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3163 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3165 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3166 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3167 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3168 * Compression Type (uncompressed, gzip, bzip2)
3174 The header is marked by a special Magic Number, and both the header
3175 and the data portions of the image are secured against corruption by
3182 Although U-Boot should support any OS or standalone application
3183 easily, the main focus has always been on Linux during the design of
3186 U-Boot includes many features that so far have been part of some
3187 special "boot loader" code within the Linux kernel. Also, any
3188 "initrd" images to be used are no longer part of one big Linux image;
3189 instead, kernel and "initrd" are separate images. This implementation
3190 serves several purposes:
3192 - the same features can be used for other OS or standalone
3193 applications (for instance: using compressed images to reduce the
3194 Flash memory footprint)
3196 - it becomes much easier to port new Linux kernel versions because
3197 lots of low-level, hardware dependent stuff are done by U-Boot
3199 - the same Linux kernel image can now be used with different "initrd"
3200 images; of course this also means that different kernel images can
3201 be run with the same "initrd". This makes testing easier (you don't
3202 have to build a new "zImage.initrd" Linux image when you just
3203 change a file in your "initrd"). Also, a field-upgrade of the
3204 software is easier now.
3210 Porting Linux to U-Boot based systems:
3211 ---------------------------------------
3213 U-Boot cannot save you from doing all the necessary modifications to
3214 configure the Linux device drivers for use with your target hardware
3215 (no, we don't intend to provide a full virtual machine interface to
3218 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3220 Just make sure your machine specific header file (for instance
3221 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3222 Information structure as we define in include/asm-<arch>/u-boot.h,
3223 and make sure that your definition of IMAP_ADDR uses the same value
3224 as your U-Boot configuration in CONFIG_SYS_IMMR.
3227 Configuring the Linux kernel:
3228 -----------------------------
3230 No specific requirements for U-Boot. Make sure you have some root
3231 device (initial ramdisk, NFS) for your target system.
3234 Building a Linux Image:
3235 -----------------------
3237 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3238 not used. If you use recent kernel source, a new build target
3239 "uImage" will exist which automatically builds an image usable by
3240 U-Boot. Most older kernels also have support for a "pImage" target,
3241 which was introduced for our predecessor project PPCBoot and uses a
3242 100% compatible format.
3251 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3252 encapsulate a compressed Linux kernel image with header information,
3253 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3255 * build a standard "vmlinux" kernel image (in ELF binary format):
3257 * convert the kernel into a raw binary image:
3259 ${CROSS_COMPILE}-objcopy -O binary \
3260 -R .note -R .comment \
3261 -S vmlinux linux.bin
3263 * compress the binary image:
3267 * package compressed binary image for U-Boot:
3269 mkimage -A ppc -O linux -T kernel -C gzip \
3270 -a 0 -e 0 -n "Linux Kernel Image" \
3271 -d linux.bin.gz uImage
3274 The "mkimage" tool can also be used to create ramdisk images for use
3275 with U-Boot, either separated from the Linux kernel image, or
3276 combined into one file. "mkimage" encapsulates the images with a 64
3277 byte header containing information about target architecture,
3278 operating system, image type, compression method, entry points, time
3279 stamp, CRC32 checksums, etc.
3281 "mkimage" can be called in two ways: to verify existing images and
3282 print the header information, or to build new images.
3284 In the first form (with "-l" option) mkimage lists the information
3285 contained in the header of an existing U-Boot image; this includes
3286 checksum verification:
3288 tools/mkimage -l image
3289 -l ==> list image header information
3291 The second form (with "-d" option) is used to build a U-Boot image
3292 from a "data file" which is used as image payload:
3294 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3295 -n name -d data_file image
3296 -A ==> set architecture to 'arch'
3297 -O ==> set operating system to 'os'
3298 -T ==> set image type to 'type'
3299 -C ==> set compression type 'comp'
3300 -a ==> set load address to 'addr' (hex)
3301 -e ==> set entry point to 'ep' (hex)
3302 -n ==> set image name to 'name'
3303 -d ==> use image data from 'datafile'
3305 Right now, all Linux kernels for PowerPC systems use the same load
3306 address (0x00000000), but the entry point address depends on the
3309 - 2.2.x kernels have the entry point at 0x0000000C,
3310 - 2.3.x and later kernels have the entry point at 0x00000000.
3312 So a typical call to build a U-Boot image would read:
3314 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3315 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3316 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3317 > examples/uImage.TQM850L
3318 Image Name: 2.4.4 kernel for TQM850L
3319 Created: Wed Jul 19 02:34:59 2000
3320 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3321 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3322 Load Address: 0x00000000
3323 Entry Point: 0x00000000
3325 To verify the contents of the image (or check for corruption):
3327 -> tools/mkimage -l examples/uImage.TQM850L
3328 Image Name: 2.4.4 kernel for TQM850L
3329 Created: Wed Jul 19 02:34:59 2000
3330 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3331 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3332 Load Address: 0x00000000
3333 Entry Point: 0x00000000
3335 NOTE: for embedded systems where boot time is critical you can trade
3336 speed for memory and install an UNCOMPRESSED image instead: this
3337 needs more space in Flash, but boots much faster since it does not
3338 need to be uncompressed:
3340 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3341 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3342 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3343 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3344 > examples/uImage.TQM850L-uncompressed
3345 Image Name: 2.4.4 kernel for TQM850L
3346 Created: Wed Jul 19 02:34:59 2000
3347 Image Type: PowerPC Linux Kernel Image (uncompressed)
3348 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3349 Load Address: 0x00000000
3350 Entry Point: 0x00000000
3353 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3354 when your kernel is intended to use an initial ramdisk:
3356 -> tools/mkimage -n 'Simple Ramdisk Image' \
3357 > -A ppc -O linux -T ramdisk -C gzip \
3358 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3359 Image Name: Simple Ramdisk Image
3360 Created: Wed Jan 12 14:01:50 2000
3361 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3362 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3363 Load Address: 0x00000000
3364 Entry Point: 0x00000000
3367 Installing a Linux Image:
3368 -------------------------
3370 To downloading a U-Boot image over the serial (console) interface,
3371 you must convert the image to S-Record format:
3373 objcopy -I binary -O srec examples/image examples/image.srec
3375 The 'objcopy' does not understand the information in the U-Boot
3376 image header, so the resulting S-Record file will be relative to
3377 address 0x00000000. To load it to a given address, you need to
3378 specify the target address as 'offset' parameter with the 'loads'
3381 Example: install the image to address 0x40100000 (which on the
3382 TQM8xxL is in the first Flash bank):
3384 => erase 40100000 401FFFFF
3390 ## Ready for S-Record download ...
3391 ~>examples/image.srec
3392 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3394 15989 15990 15991 15992
3395 [file transfer complete]
3397 ## Start Addr = 0x00000000
3400 You can check the success of the download using the 'iminfo' command;
3401 this includes a checksum verification so you can be sure no data
3402 corruption happened:
3406 ## Checking Image at 40100000 ...
3407 Image Name: 2.2.13 for initrd on TQM850L
3408 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3409 Data Size: 335725 Bytes = 327 kB = 0 MB
3410 Load Address: 00000000
3411 Entry Point: 0000000c
3412 Verifying Checksum ... OK
3418 The "bootm" command is used to boot an application that is stored in
3419 memory (RAM or Flash). In case of a Linux kernel image, the contents
3420 of the "bootargs" environment variable is passed to the kernel as
3421 parameters. You can check and modify this variable using the
3422 "printenv" and "setenv" commands:
3425 => printenv bootargs
3426 bootargs=root=/dev/ram
3428 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3430 => printenv bootargs
3431 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3434 ## Booting Linux kernel at 40020000 ...
3435 Image Name: 2.2.13 for NFS on TQM850L
3436 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3437 Data Size: 381681 Bytes = 372 kB = 0 MB
3438 Load Address: 00000000
3439 Entry Point: 0000000c
3440 Verifying Checksum ... OK
3441 Uncompressing Kernel Image ... OK
3442 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
3443 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3444 time_init: decrementer frequency = 187500000/60
3445 Calibrating delay loop... 49.77 BogoMIPS
3446 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3449 If you want to boot a Linux kernel with initial RAM disk, you pass
3450 the memory addresses of both the kernel and the initrd image (PPBCOOT
3451 format!) to the "bootm" command:
3453 => imi 40100000 40200000
3455 ## Checking Image at 40100000 ...
3456 Image Name: 2.2.13 for initrd on TQM850L
3457 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3458 Data Size: 335725 Bytes = 327 kB = 0 MB
3459 Load Address: 00000000
3460 Entry Point: 0000000c
3461 Verifying Checksum ... OK
3463 ## Checking Image at 40200000 ...
3464 Image Name: Simple Ramdisk Image
3465 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3466 Data Size: 566530 Bytes = 553 kB = 0 MB
3467 Load Address: 00000000
3468 Entry Point: 00000000
3469 Verifying Checksum ... OK
3471 => bootm 40100000 40200000
3472 ## Booting Linux kernel at 40100000 ...
3473 Image Name: 2.2.13 for initrd on TQM850L
3474 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3475 Data Size: 335725 Bytes = 327 kB = 0 MB
3476 Load Address: 00000000
3477 Entry Point: 0000000c
3478 Verifying Checksum ... OK
3479 Uncompressing Kernel Image ... OK
3480 ## Loading RAMDisk Image at 40200000 ...
3481 Image Name: Simple Ramdisk Image
3482 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3483 Data Size: 566530 Bytes = 553 kB = 0 MB
3484 Load Address: 00000000
3485 Entry Point: 00000000
3486 Verifying Checksum ... OK
3487 Loading Ramdisk ... OK
3488 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
3489 Boot arguments: root=/dev/ram
3490 time_init: decrementer frequency = 187500000/60
3491 Calibrating delay loop... 49.77 BogoMIPS
3493 RAMDISK: Compressed image found at block 0
3494 VFS: Mounted root (ext2 filesystem).
3498 Boot Linux and pass a flat device tree:
3501 First, U-Boot must be compiled with the appropriate defines. See the section
3502 titled "Linux Kernel Interface" above for a more in depth explanation. The
3503 following is an example of how to start a kernel and pass an updated
3509 oft=oftrees/mpc8540ads.dtb
3510 => tftp $oftaddr $oft
3511 Speed: 1000, full duplex
3513 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3514 Filename 'oftrees/mpc8540ads.dtb'.
3515 Load address: 0x300000
3518 Bytes transferred = 4106 (100a hex)
3519 => tftp $loadaddr $bootfile
3520 Speed: 1000, full duplex
3522 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3524 Load address: 0x200000
3525 Loading:############
3527 Bytes transferred = 1029407 (fb51f hex)
3532 => bootm $loadaddr - $oftaddr
3533 ## Booting image at 00200000 ...
3534 Image Name: Linux-2.6.17-dirty
3535 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3536 Data Size: 1029343 Bytes = 1005.2 kB
3537 Load Address: 00000000
3538 Entry Point: 00000000
3539 Verifying Checksum ... OK
3540 Uncompressing Kernel Image ... OK
3541 Booting using flat device tree at 0x300000
3542 Using MPC85xx ADS machine description
3543 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3547 More About U-Boot Image Types:
3548 ------------------------------
3550 U-Boot supports the following image types:
3552 "Standalone Programs" are directly runnable in the environment
3553 provided by U-Boot; it is expected that (if they behave
3554 well) you can continue to work in U-Boot after return from
3555 the Standalone Program.
3556 "OS Kernel Images" are usually images of some Embedded OS which
3557 will take over control completely. Usually these programs
3558 will install their own set of exception handlers, device
3559 drivers, set up the MMU, etc. - this means, that you cannot
3560 expect to re-enter U-Boot except by resetting the CPU.
3561 "RAMDisk Images" are more or less just data blocks, and their
3562 parameters (address, size) are passed to an OS kernel that is
3564 "Multi-File Images" contain several images, typically an OS
3565 (Linux) kernel image and one or more data images like
3566 RAMDisks. This construct is useful for instance when you want
3567 to boot over the network using BOOTP etc., where the boot
3568 server provides just a single image file, but you want to get
3569 for instance an OS kernel and a RAMDisk image.
3571 "Multi-File Images" start with a list of image sizes, each
3572 image size (in bytes) specified by an "uint32_t" in network
3573 byte order. This list is terminated by an "(uint32_t)0".
3574 Immediately after the terminating 0 follow the images, one by
3575 one, all aligned on "uint32_t" boundaries (size rounded up to
3576 a multiple of 4 bytes).
3578 "Firmware Images" are binary images containing firmware (like
3579 U-Boot or FPGA images) which usually will be programmed to
3582 "Script files" are command sequences that will be executed by
3583 U-Boot's command interpreter; this feature is especially
3584 useful when you configure U-Boot to use a real shell (hush)
3585 as command interpreter.
3591 One of the features of U-Boot is that you can dynamically load and
3592 run "standalone" applications, which can use some resources of
3593 U-Boot like console I/O functions or interrupt services.
3595 Two simple examples are included with the sources:
3600 'examples/hello_world.c' contains a small "Hello World" Demo
3601 application; it is automatically compiled when you build U-Boot.
3602 It's configured to run at address 0x00040004, so you can play with it
3606 ## Ready for S-Record download ...
3607 ~>examples/hello_world.srec
3608 1 2 3 4 5 6 7 8 9 10 11 ...
3609 [file transfer complete]
3611 ## Start Addr = 0x00040004
3613 => go 40004 Hello World! This is a test.
3614 ## Starting application at 0x00040004 ...
3625 Hit any key to exit ...
3627 ## Application terminated, rc = 0x0
3629 Another example, which demonstrates how to register a CPM interrupt
3630 handler with the U-Boot code, can be found in 'examples/timer.c'.
3631 Here, a CPM timer is set up to generate an interrupt every second.
3632 The interrupt service routine is trivial, just printing a '.'
3633 character, but this is just a demo program. The application can be
3634 controlled by the following keys:
3636 ? - print current values og the CPM Timer registers
3637 b - enable interrupts and start timer
3638 e - stop timer and disable interrupts
3639 q - quit application
3642 ## Ready for S-Record download ...
3643 ~>examples/timer.srec
3644 1 2 3 4 5 6 7 8 9 10 11 ...
3645 [file transfer complete]
3647 ## Start Addr = 0x00040004
3650 ## Starting application at 0x00040004 ...
3653 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3656 [q, b, e, ?] Set interval 1000000 us
3659 [q, b, e, ?] ........
3660 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3663 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3666 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3669 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3671 [q, b, e, ?] ...Stopping timer
3673 [q, b, e, ?] ## Application terminated, rc = 0x0
3679 Over time, many people have reported problems when trying to use the
3680 "minicom" terminal emulation program for serial download. I (wd)
3681 consider minicom to be broken, and recommend not to use it. Under
3682 Unix, I recommend to use C-Kermit for general purpose use (and
3683 especially for kermit binary protocol download ("loadb" command), and
3684 use "cu" for S-Record download ("loads" command).
3686 Nevertheless, if you absolutely want to use it try adding this
3687 configuration to your "File transfer protocols" section:
3689 Name Program Name U/D FullScr IO-Red. Multi
3690 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3691 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3697 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3698 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3700 Building requires a cross environment; it is known to work on
3701 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3702 need gmake since the Makefiles are not compatible with BSD make).
3703 Note that the cross-powerpc package does not install include files;
3704 attempting to build U-Boot will fail because <machine/ansi.h> is
3705 missing. This file has to be installed and patched manually:
3707 # cd /usr/pkg/cross/powerpc-netbsd/include
3709 # ln -s powerpc machine
3710 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3711 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3713 Native builds *don't* work due to incompatibilities between native
3714 and U-Boot include files.
3716 Booting assumes that (the first part of) the image booted is a
3717 stage-2 loader which in turn loads and then invokes the kernel
3718 proper. Loader sources will eventually appear in the NetBSD source
3719 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3720 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3723 Implementation Internals:
3724 =========================
3726 The following is not intended to be a complete description of every
3727 implementation detail. However, it should help to understand the
3728 inner workings of U-Boot and make it easier to port it to custom
3732 Initial Stack, Global Data:
3733 ---------------------------
3735 The implementation of U-Boot is complicated by the fact that U-Boot
3736 starts running out of ROM (flash memory), usually without access to
3737 system RAM (because the memory controller is not initialized yet).
3738 This means that we don't have writable Data or BSS segments, and BSS
3739 is not initialized as zero. To be able to get a C environment working
3740 at all, we have to allocate at least a minimal stack. Implementation
3741 options for this are defined and restricted by the CPU used: Some CPU
3742 models provide on-chip memory (like the IMMR area on MPC8xx and
3743 MPC826x processors), on others (parts of) the data cache can be
3744 locked as (mis-) used as memory, etc.
3746 Chris Hallinan posted a good summary of these issues to the
3747 U-Boot mailing list:
3749 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3750 From: "Chris Hallinan" <clh@net1plus.com>
3751 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3754 Correct me if I'm wrong, folks, but the way I understand it
3755 is this: Using DCACHE as initial RAM for Stack, etc, does not
3756 require any physical RAM backing up the cache. The cleverness
3757 is that the cache is being used as a temporary supply of
3758 necessary storage before the SDRAM controller is setup. It's
3759 beyond the scope of this list to explain the details, but you
3760 can see how this works by studying the cache architecture and
3761 operation in the architecture and processor-specific manuals.
3763 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3764 is another option for the system designer to use as an
3765 initial stack/RAM area prior to SDRAM being available. Either
3766 option should work for you. Using CS 4 should be fine if your
3767 board designers haven't used it for something that would
3768 cause you grief during the initial boot! It is frequently not
3771 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3772 with your processor/board/system design. The default value
3773 you will find in any recent u-boot distribution in
3774 walnut.h should work for you. I'd set it to a value larger
3775 than your SDRAM module. If you have a 64MB SDRAM module, set
3776 it above 400_0000. Just make sure your board has no resources
3777 that are supposed to respond to that address! That code in
3778 start.S has been around a while and should work as is when
3779 you get the config right.
3784 It is essential to remember this, since it has some impact on the C
3785 code for the initialization procedures:
3787 * Initialized global data (data segment) is read-only. Do not attempt
3790 * Do not use any uninitialized global data (or implicitely initialized
3791 as zero data - BSS segment) at all - this is undefined, initiali-
3792 zation is performed later (when relocating to RAM).
3794 * Stack space is very limited. Avoid big data buffers or things like
3797 Having only the stack as writable memory limits means we cannot use
3798 normal global data to share information beween the code. But it
3799 turned out that the implementation of U-Boot can be greatly
3800 simplified by making a global data structure (gd_t) available to all
3801 functions. We could pass a pointer to this data as argument to _all_
3802 functions, but this would bloat the code. Instead we use a feature of
3803 the GCC compiler (Global Register Variables) to share the data: we
3804 place a pointer (gd) to the global data into a register which we
3805 reserve for this purpose.
3807 When choosing a register for such a purpose we are restricted by the
3808 relevant (E)ABI specifications for the current architecture, and by
3809 GCC's implementation.
3811 For PowerPC, the following registers have specific use:
3813 R2: reserved for system use
3814 R3-R4: parameter passing and return values
3815 R5-R10: parameter passing
3816 R13: small data area pointer
3820 (U-Boot also uses R14 as internal GOT pointer.)
3822 ==> U-Boot will use R2 to hold a pointer to the global data
3824 Note: on PPC, we could use a static initializer (since the
3825 address of the global data structure is known at compile time),
3826 but it turned out that reserving a register results in somewhat
3827 smaller code - although the code savings are not that big (on
3828 average for all boards 752 bytes for the whole U-Boot image,
3829 624 text + 127 data).
3831 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3832 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3834 ==> U-Boot will use P5 to hold a pointer to the global data
3836 On ARM, the following registers are used:
3838 R0: function argument word/integer result
3839 R1-R3: function argument word
3841 R10: stack limit (used only if stack checking if enabled)
3842 R11: argument (frame) pointer
3843 R12: temporary workspace
3846 R15: program counter
3848 ==> U-Boot will use R8 to hold a pointer to the global data
3850 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3851 or current versions of GCC may "optimize" the code too much.
3856 U-Boot runs in system state and uses physical addresses, i.e. the
3857 MMU is not used either for address mapping nor for memory protection.
3859 The available memory is mapped to fixed addresses using the memory
3860 controller. In this process, a contiguous block is formed for each
3861 memory type (Flash, SDRAM, SRAM), even when it consists of several
3862 physical memory banks.
3864 U-Boot is installed in the first 128 kB of the first Flash bank (on
3865 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3866 booting and sizing and initializing DRAM, the code relocates itself
3867 to the upper end of DRAM. Immediately below the U-Boot code some
3868 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3869 configuration setting]. Below that, a structure with global Board
3870 Info data is placed, followed by the stack (growing downward).
3872 Additionally, some exception handler code is copied to the low 8 kB
3873 of DRAM (0x00000000 ... 0x00001FFF).
3875 So a typical memory configuration with 16 MB of DRAM could look like
3878 0x0000 0000 Exception Vector code
3881 0x0000 2000 Free for Application Use
3887 0x00FB FF20 Monitor Stack (Growing downward)
3888 0x00FB FFAC Board Info Data and permanent copy of global data
3889 0x00FC 0000 Malloc Arena
3892 0x00FE 0000 RAM Copy of Monitor Code
3893 ... eventually: LCD or video framebuffer
3894 ... eventually: pRAM (Protected RAM - unchanged by reset)
3895 0x00FF FFFF [End of RAM]
3898 System Initialization:
3899 ----------------------
3901 In the reset configuration, U-Boot starts at the reset entry point
3902 (on most PowerPC systems at address 0x00000100). Because of the reset
3903 configuration for CS0# this is a mirror of the onboard Flash memory.
3904 To be able to re-map memory U-Boot then jumps to its link address.
3905 To be able to implement the initialization code in C, a (small!)
3906 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3907 which provide such a feature like MPC8xx or MPC8260), or in a locked
3908 part of the data cache. After that, U-Boot initializes the CPU core,
3909 the caches and the SIU.
3911 Next, all (potentially) available memory banks are mapped using a
3912 preliminary mapping. For example, we put them on 512 MB boundaries
3913 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3914 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3915 programmed for SDRAM access. Using the temporary configuration, a
3916 simple memory test is run that determines the size of the SDRAM
3919 When there is more than one SDRAM bank, and the banks are of
3920 different size, the largest is mapped first. For equal size, the first
3921 bank (CS2#) is mapped first. The first mapping is always for address
3922 0x00000000, with any additional banks following immediately to create
3923 contiguous memory starting from 0.
3925 Then, the monitor installs itself at the upper end of the SDRAM area
3926 and allocates memory for use by malloc() and for the global Board
3927 Info data; also, the exception vector code is copied to the low RAM
3928 pages, and the final stack is set up.
3930 Only after this relocation will you have a "normal" C environment;
3931 until that you are restricted in several ways, mostly because you are
3932 running from ROM, and because the code will have to be relocated to a
3936 U-Boot Porting Guide:
3937 ----------------------
3939 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3943 int main (int argc, char *argv[])
3945 sighandler_t no_more_time;
3947 signal (SIGALRM, no_more_time);
3948 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3950 if (available_money > available_manpower) {
3951 pay consultant to port U-Boot;
3955 Download latest U-Boot source;
3957 Subscribe to u-boot mailing list;
3960 email ("Hi, I am new to U-Boot, how do I get started?");
3964 Read the README file in the top level directory;
3965 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3966 Read the source, Luke;
3969 if (available_money > toLocalCurrency ($2500)) {
3972 Add a lot of aggravation and time;
3975 Create your own board support subdirectory;
3977 Create your own board config file;
3981 Add / modify source code;
3985 email ("Hi, I am having problems...");
3987 Send patch file to Wolfgang;
3992 void no_more_time (int sig)
4001 All contributions to U-Boot should conform to the Linux kernel
4002 coding style; see the file "Documentation/CodingStyle" and the script
4003 "scripts/Lindent" in your Linux kernel source directory. In sources
4004 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4005 spaces before parameters to function calls) is actually used.
4007 Source files originating from a different project (for example the
4008 MTD subsystem) are generally exempt from these guidelines and are not
4009 reformated to ease subsequent migration to newer versions of those
4012 Please note that U-Boot is implemented in C (and to some small parts in
4013 Assembler); no C++ is used, so please do not use C++ style comments (//)
4016 Please also stick to the following formatting rules:
4017 - remove any trailing white space
4018 - use TAB characters for indentation, not spaces
4019 - make sure NOT to use DOS '\r\n' line feeds
4020 - do not add more than 2 empty lines to source files
4021 - do not add trailing empty lines to source files
4023 Submissions which do not conform to the standards may be returned
4024 with a request to reformat the changes.
4030 Since the number of patches for U-Boot is growing, we need to
4031 establish some rules. Submissions which do not conform to these rules
4032 may be rejected, even when they contain important and valuable stuff.
4034 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4036 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4037 see http://lists.denx.de/mailman/listinfo/u-boot
4039 When you send a patch, please include the following information with
4042 * For bug fixes: a description of the bug and how your patch fixes
4043 this bug. Please try to include a way of demonstrating that the
4044 patch actually fixes something.
4046 * For new features: a description of the feature and your
4049 * A CHANGELOG entry as plaintext (separate from the patch)
4051 * For major contributions, your entry to the CREDITS file
4053 * When you add support for a new board, don't forget to add this
4054 board to the MAKEALL script, too.
4056 * If your patch adds new configuration options, don't forget to
4057 document these in the README file.
4059 * The patch itself. If you are using git (which is *strongly*
4060 recommended) you can easily generate the patch using the
4061 "git-format-patch". If you then use "git-send-email" to send it to
4062 the U-Boot mailing list, you will avoid most of the common problems
4063 with some other mail clients.
4065 If you cannot use git, use "diff -purN OLD NEW". If your version of
4066 diff does not support these options, then get the latest version of
4069 The current directory when running this command shall be the parent
4070 directory of the U-Boot source tree (i. e. please make sure that
4071 your patch includes sufficient directory information for the
4074 We prefer patches as plain text. MIME attachments are discouraged,
4075 and compressed attachments must not be used.
4077 * If one logical set of modifications affects or creates several
4078 files, all these changes shall be submitted in a SINGLE patch file.
4080 * Changesets that contain different, unrelated modifications shall be
4081 submitted as SEPARATE patches, one patch per changeset.
4086 * Before sending the patch, run the MAKEALL script on your patched
4087 source tree and make sure that no errors or warnings are reported
4088 for any of the boards.
4090 * Keep your modifications to the necessary minimum: A patch
4091 containing several unrelated changes or arbitrary reformats will be
4092 returned with a request to re-formatting / split it.
4094 * If you modify existing code, make sure that your new code does not
4095 add to the memory footprint of the code ;-) Small is beautiful!
4096 When adding new features, these should compile conditionally only
4097 (using #ifdef), and the resulting code with the new feature
4098 disabled must not need more memory than the old code without your
4101 * Remember that there is a size limit of 100 kB per message on the
4102 u-boot mailing list. Bigger patches will be moderated. If they are
4103 reasonable and not too big, they will be acknowledged. But patches
4104 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob