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.
1512 CONFIG_SOFT_I2C_READ_REPEATED_START
1514 defining this will force the i2c_read() function in
1515 the soft_i2c driver to perform an I2C repeated start
1516 between writing the address pointer and reading the
1517 data. If this define is omitted the default behaviour
1518 of doing a stop-start sequence will be used. Most I2C
1519 devices can use either method, but some require one or
1522 - SPI Support: CONFIG_SPI
1524 Enables SPI driver (so far only tested with
1525 SPI EEPROM, also an instance works with Crystal A/D and
1526 D/As on the SACSng board)
1530 Enables extended (16-bit) SPI EEPROM addressing.
1531 (symmetrical to CONFIG_I2C_X)
1535 Enables a software (bit-bang) SPI driver rather than
1536 using hardware support. This is a general purpose
1537 driver that only requires three general I/O port pins
1538 (two outputs, one input) to function. If this is
1539 defined, the board configuration must define several
1540 SPI configuration items (port pins to use, etc). For
1541 an example, see include/configs/sacsng.h.
1545 Enables a hardware SPI driver for general-purpose reads
1546 and writes. As with CONFIG_SOFT_SPI, the board configuration
1547 must define a list of chip-select function pointers.
1548 Currently supported on some MPC8xxx processors. For an
1549 example, see include/configs/mpc8349emds.h.
1553 Enables the driver for the SPI controllers on i.MX and MXC
1554 SoCs. Currently only i.MX31 is supported.
1556 - FPGA Support: CONFIG_FPGA
1558 Enables FPGA subsystem.
1560 CONFIG_FPGA_<vendor>
1562 Enables support for specific chip vendors.
1565 CONFIG_FPGA_<family>
1567 Enables support for FPGA family.
1568 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1572 Specify the number of FPGA devices to support.
1574 CONFIG_SYS_FPGA_PROG_FEEDBACK
1576 Enable printing of hash marks during FPGA configuration.
1578 CONFIG_SYS_FPGA_CHECK_BUSY
1580 Enable checks on FPGA configuration interface busy
1581 status by the configuration function. This option
1582 will require a board or device specific function to
1587 If defined, a function that provides delays in the FPGA
1588 configuration driver.
1590 CONFIG_SYS_FPGA_CHECK_CTRLC
1591 Allow Control-C to interrupt FPGA configuration
1593 CONFIG_SYS_FPGA_CHECK_ERROR
1595 Check for configuration errors during FPGA bitfile
1596 loading. For example, abort during Virtex II
1597 configuration if the INIT_B line goes low (which
1598 indicated a CRC error).
1600 CONFIG_SYS_FPGA_WAIT_INIT
1602 Maximum time to wait for the INIT_B line to deassert
1603 after PROB_B has been deasserted during a Virtex II
1604 FPGA configuration sequence. The default time is 500
1607 CONFIG_SYS_FPGA_WAIT_BUSY
1609 Maximum time to wait for BUSY to deassert during
1610 Virtex II FPGA configuration. The default is 5 ms.
1612 CONFIG_SYS_FPGA_WAIT_CONFIG
1614 Time to wait after FPGA configuration. The default is
1617 - Configuration Management:
1620 If defined, this string will be added to the U-Boot
1621 version information (U_BOOT_VERSION)
1623 - Vendor Parameter Protection:
1625 U-Boot considers the values of the environment
1626 variables "serial#" (Board Serial Number) and
1627 "ethaddr" (Ethernet Address) to be parameters that
1628 are set once by the board vendor / manufacturer, and
1629 protects these variables from casual modification by
1630 the user. Once set, these variables are read-only,
1631 and write or delete attempts are rejected. You can
1632 change this behaviour:
1634 If CONFIG_ENV_OVERWRITE is #defined in your config
1635 file, the write protection for vendor parameters is
1636 completely disabled. Anybody can change or delete
1639 Alternatively, if you #define _both_ CONFIG_ETHADDR
1640 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1641 Ethernet address is installed in the environment,
1642 which can be changed exactly ONCE by the user. [The
1643 serial# is unaffected by this, i. e. it remains
1649 Define this variable to enable the reservation of
1650 "protected RAM", i. e. RAM which is not overwritten
1651 by U-Boot. Define CONFIG_PRAM to hold the number of
1652 kB you want to reserve for pRAM. You can overwrite
1653 this default value by defining an environment
1654 variable "pram" to the number of kB you want to
1655 reserve. Note that the board info structure will
1656 still show the full amount of RAM. If pRAM is
1657 reserved, a new environment variable "mem" will
1658 automatically be defined to hold the amount of
1659 remaining RAM in a form that can be passed as boot
1660 argument to Linux, for instance like that:
1662 setenv bootargs ... mem=\${mem}
1665 This way you can tell Linux not to use this memory,
1666 either, which results in a memory region that will
1667 not be affected by reboots.
1669 *WARNING* If your board configuration uses automatic
1670 detection of the RAM size, you must make sure that
1671 this memory test is non-destructive. So far, the
1672 following board configurations are known to be
1675 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1676 HERMES, IP860, RPXlite, LWMON, LANTEC,
1677 PCU_E, FLAGADM, TQM8260
1682 Define this variable to stop the system in case of a
1683 fatal error, so that you have to reset it manually.
1684 This is probably NOT a good idea for an embedded
1685 system where you want the system to reboot
1686 automatically as fast as possible, but it may be
1687 useful during development since you can try to debug
1688 the conditions that lead to the situation.
1690 CONFIG_NET_RETRY_COUNT
1692 This variable defines the number of retries for
1693 network operations like ARP, RARP, TFTP, or BOOTP
1694 before giving up the operation. If not defined, a
1695 default value of 5 is used.
1699 Timeout waiting for an ARP reply in milliseconds.
1701 - Command Interpreter:
1702 CONFIG_AUTO_COMPLETE
1704 Enable auto completion of commands using TAB.
1706 Note that this feature has NOT been implemented yet
1707 for the "hush" shell.
1710 CONFIG_SYS_HUSH_PARSER
1712 Define this variable to enable the "hush" shell (from
1713 Busybox) as command line interpreter, thus enabling
1714 powerful command line syntax like
1715 if...then...else...fi conditionals or `&&' and '||'
1716 constructs ("shell scripts").
1718 If undefined, you get the old, much simpler behaviour
1719 with a somewhat smaller memory footprint.
1722 CONFIG_SYS_PROMPT_HUSH_PS2
1724 This defines the secondary prompt string, which is
1725 printed when the command interpreter needs more input
1726 to complete a command. Usually "> ".
1730 In the current implementation, the local variables
1731 space and global environment variables space are
1732 separated. Local variables are those you define by
1733 simply typing `name=value'. To access a local
1734 variable later on, you have write `$name' or
1735 `${name}'; to execute the contents of a variable
1736 directly type `$name' at the command prompt.
1738 Global environment variables are those you use
1739 setenv/printenv to work with. To run a command stored
1740 in such a variable, you need to use the run command,
1741 and you must not use the '$' sign to access them.
1743 To store commands and special characters in a
1744 variable, please use double quotation marks
1745 surrounding the whole text of the variable, instead
1746 of the backslashes before semicolons and special
1749 - Commandline Editing and History:
1750 CONFIG_CMDLINE_EDITING
1752 Enable editing and History functions for interactive
1753 commandline input operations
1755 - Default Environment:
1756 CONFIG_EXTRA_ENV_SETTINGS
1758 Define this to contain any number of null terminated
1759 strings (variable = value pairs) that will be part of
1760 the default environment compiled into the boot image.
1762 For example, place something like this in your
1763 board's config file:
1765 #define CONFIG_EXTRA_ENV_SETTINGS \
1769 Warning: This method is based on knowledge about the
1770 internal format how the environment is stored by the
1771 U-Boot code. This is NOT an official, exported
1772 interface! Although it is unlikely that this format
1773 will change soon, there is no guarantee either.
1774 You better know what you are doing here.
1776 Note: overly (ab)use of the default environment is
1777 discouraged. Make sure to check other ways to preset
1778 the environment like the autoscript function or the
1781 - DataFlash Support:
1782 CONFIG_HAS_DATAFLASH
1784 Defining this option enables DataFlash features and
1785 allows to read/write in Dataflash via the standard
1788 - SystemACE Support:
1791 Adding this option adds support for Xilinx SystemACE
1792 chips attached via some sort of local bus. The address
1793 of the chip must also be defined in the
1794 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1796 #define CONFIG_SYSTEMACE
1797 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1799 When SystemACE support is added, the "ace" device type
1800 becomes available to the fat commands, i.e. fatls.
1802 - TFTP Fixed UDP Port:
1805 If this is defined, the environment variable tftpsrcp
1806 is used to supply the TFTP UDP source port value.
1807 If tftpsrcp isn't defined, the normal pseudo-random port
1808 number generator is used.
1810 Also, the environment variable tftpdstp is used to supply
1811 the TFTP UDP destination port value. If tftpdstp isn't
1812 defined, the normal port 69 is used.
1814 The purpose for tftpsrcp is to allow a TFTP server to
1815 blindly start the TFTP transfer using the pre-configured
1816 target IP address and UDP port. This has the effect of
1817 "punching through" the (Windows XP) firewall, allowing
1818 the remainder of the TFTP transfer to proceed normally.
1819 A better solution is to properly configure the firewall,
1820 but sometimes that is not allowed.
1822 - Show boot progress:
1823 CONFIG_SHOW_BOOT_PROGRESS
1825 Defining this option allows to add some board-
1826 specific code (calling a user-provided function
1827 "show_boot_progress(int)") that enables you to show
1828 the system's boot progress on some display (for
1829 example, some LED's) on your board. At the moment,
1830 the following checkpoints are implemented:
1832 - Automatic software updates via TFTP server
1834 CONFIG_UPDATE_TFTP_CNT_MAX
1835 CONFIG_UPDATE_TFTP_MSEC_MAX
1837 These options enable and control the auto-update feature;
1838 for a more detailed description refer to doc/README.update.
1840 Legacy uImage format:
1843 1 common/cmd_bootm.c before attempting to boot an image
1844 -1 common/cmd_bootm.c Image header has bad magic number
1845 2 common/cmd_bootm.c Image header has correct magic number
1846 -2 common/cmd_bootm.c Image header has bad checksum
1847 3 common/cmd_bootm.c Image header has correct checksum
1848 -3 common/cmd_bootm.c Image data has bad checksum
1849 4 common/cmd_bootm.c Image data has correct checksum
1850 -4 common/cmd_bootm.c Image is for unsupported architecture
1851 5 common/cmd_bootm.c Architecture check OK
1852 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1853 6 common/cmd_bootm.c Image Type check OK
1854 -6 common/cmd_bootm.c gunzip uncompression error
1855 -7 common/cmd_bootm.c Unimplemented compression type
1856 7 common/cmd_bootm.c Uncompression OK
1857 8 common/cmd_bootm.c No uncompress/copy overwrite error
1858 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1860 9 common/image.c Start initial ramdisk verification
1861 -10 common/image.c Ramdisk header has bad magic number
1862 -11 common/image.c Ramdisk header has bad checksum
1863 10 common/image.c Ramdisk header is OK
1864 -12 common/image.c Ramdisk data has bad checksum
1865 11 common/image.c Ramdisk data has correct checksum
1866 12 common/image.c Ramdisk verification complete, start loading
1867 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1868 13 common/image.c Start multifile image verification
1869 14 common/image.c No initial ramdisk, no multifile, continue.
1871 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1873 -30 lib_ppc/board.c Fatal error, hang the system
1874 -31 post/post.c POST test failed, detected by post_output_backlog()
1875 -32 post/post.c POST test failed, detected by post_run_single()
1877 34 common/cmd_doc.c before loading a Image from a DOC device
1878 -35 common/cmd_doc.c Bad usage of "doc" command
1879 35 common/cmd_doc.c correct usage of "doc" command
1880 -36 common/cmd_doc.c No boot device
1881 36 common/cmd_doc.c correct boot device
1882 -37 common/cmd_doc.c Unknown Chip ID on boot device
1883 37 common/cmd_doc.c correct chip ID found, device available
1884 -38 common/cmd_doc.c Read Error on boot device
1885 38 common/cmd_doc.c reading Image header from DOC device OK
1886 -39 common/cmd_doc.c Image header has bad magic number
1887 39 common/cmd_doc.c Image header has correct magic number
1888 -40 common/cmd_doc.c Error reading Image from DOC device
1889 40 common/cmd_doc.c Image header has correct magic number
1890 41 common/cmd_ide.c before loading a Image from a IDE device
1891 -42 common/cmd_ide.c Bad usage of "ide" command
1892 42 common/cmd_ide.c correct usage of "ide" command
1893 -43 common/cmd_ide.c No boot device
1894 43 common/cmd_ide.c boot device found
1895 -44 common/cmd_ide.c Device not available
1896 44 common/cmd_ide.c Device available
1897 -45 common/cmd_ide.c wrong partition selected
1898 45 common/cmd_ide.c partition selected
1899 -46 common/cmd_ide.c Unknown partition table
1900 46 common/cmd_ide.c valid partition table found
1901 -47 common/cmd_ide.c Invalid partition type
1902 47 common/cmd_ide.c correct partition type
1903 -48 common/cmd_ide.c Error reading Image Header on boot device
1904 48 common/cmd_ide.c reading Image Header from IDE device OK
1905 -49 common/cmd_ide.c Image header has bad magic number
1906 49 common/cmd_ide.c Image header has correct magic number
1907 -50 common/cmd_ide.c Image header has bad checksum
1908 50 common/cmd_ide.c Image header has correct checksum
1909 -51 common/cmd_ide.c Error reading Image from IDE device
1910 51 common/cmd_ide.c reading Image from IDE device OK
1911 52 common/cmd_nand.c before loading a Image from a NAND device
1912 -53 common/cmd_nand.c Bad usage of "nand" command
1913 53 common/cmd_nand.c correct usage of "nand" command
1914 -54 common/cmd_nand.c No boot device
1915 54 common/cmd_nand.c boot device found
1916 -55 common/cmd_nand.c Unknown Chip ID on boot device
1917 55 common/cmd_nand.c correct chip ID found, device available
1918 -56 common/cmd_nand.c Error reading Image Header on boot device
1919 56 common/cmd_nand.c reading Image Header from NAND device OK
1920 -57 common/cmd_nand.c Image header has bad magic number
1921 57 common/cmd_nand.c Image header has correct magic number
1922 -58 common/cmd_nand.c Error reading Image from NAND device
1923 58 common/cmd_nand.c reading Image from NAND device OK
1925 -60 common/env_common.c Environment has a bad CRC, using default
1927 64 net/eth.c starting with Ethernet configuration.
1928 -64 net/eth.c no Ethernet found.
1929 65 net/eth.c Ethernet found.
1931 -80 common/cmd_net.c usage wrong
1932 80 common/cmd_net.c before calling NetLoop()
1933 -81 common/cmd_net.c some error in NetLoop() occurred
1934 81 common/cmd_net.c NetLoop() back without error
1935 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1936 82 common/cmd_net.c trying automatic boot
1937 83 common/cmd_net.c running autoscript
1938 -83 common/cmd_net.c some error in automatic boot or autoscript
1939 84 common/cmd_net.c end without errors
1944 100 common/cmd_bootm.c Kernel FIT Image has correct format
1945 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1946 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1947 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1948 102 common/cmd_bootm.c Kernel unit name specified
1949 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1950 103 common/cmd_bootm.c Found configuration node
1951 104 common/cmd_bootm.c Got kernel subimage node offset
1952 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1953 105 common/cmd_bootm.c Kernel subimage hash verification OK
1954 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1955 106 common/cmd_bootm.c Architecture check OK
1956 -106 common/cmd_bootm.c Kernel subimage has wrong type
1957 107 common/cmd_bootm.c Kernel subimage type OK
1958 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1959 108 common/cmd_bootm.c Got kernel subimage data/size
1960 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1961 -109 common/cmd_bootm.c Can't get kernel subimage type
1962 -110 common/cmd_bootm.c Can't get kernel subimage comp
1963 -111 common/cmd_bootm.c Can't get kernel subimage os
1964 -112 common/cmd_bootm.c Can't get kernel subimage load address
1965 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1967 120 common/image.c Start initial ramdisk verification
1968 -120 common/image.c Ramdisk FIT image has incorrect format
1969 121 common/image.c Ramdisk FIT image has correct format
1970 122 common/image.c No ramdisk subimage unit name, using configuration
1971 -122 common/image.c Can't get configuration for ramdisk subimage
1972 123 common/image.c Ramdisk unit name specified
1973 -124 common/image.c Can't get ramdisk subimage node offset
1974 125 common/image.c Got ramdisk subimage node offset
1975 -125 common/image.c Ramdisk subimage hash verification failed
1976 126 common/image.c Ramdisk subimage hash verification OK
1977 -126 common/image.c Ramdisk subimage for unsupported architecture
1978 127 common/image.c Architecture check OK
1979 -127 common/image.c Can't get ramdisk subimage data/size
1980 128 common/image.c Got ramdisk subimage data/size
1981 129 common/image.c Can't get ramdisk load address
1982 -129 common/image.c Got ramdisk load address
1984 -130 common/cmd_doc.c Incorrect FIT image format
1985 131 common/cmd_doc.c FIT image format OK
1987 -140 common/cmd_ide.c Incorrect FIT image format
1988 141 common/cmd_ide.c FIT image format OK
1990 -150 common/cmd_nand.c Incorrect FIT image format
1991 151 common/cmd_nand.c FIT image format OK
1997 [so far only for SMDK2400 and TRAB boards]
1999 - Modem support enable:
2000 CONFIG_MODEM_SUPPORT
2002 - RTS/CTS Flow control enable:
2005 - Modem debug support:
2006 CONFIG_MODEM_SUPPORT_DEBUG
2008 Enables debugging stuff (char screen[1024], dbg())
2009 for modem support. Useful only with BDI2000.
2011 - Interrupt support (PPC):
2013 There are common interrupt_init() and timer_interrupt()
2014 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2015 for CPU specific initialization. interrupt_init_cpu()
2016 should set decrementer_count to appropriate value. If
2017 CPU resets decrementer automatically after interrupt
2018 (ppc4xx) it should set decrementer_count to zero.
2019 timer_interrupt() calls timer_interrupt_cpu() for CPU
2020 specific handling. If board has watchdog / status_led
2021 / other_activity_monitor it works automatically from
2022 general timer_interrupt().
2026 In the target system modem support is enabled when a
2027 specific key (key combination) is pressed during
2028 power-on. Otherwise U-Boot will boot normally
2029 (autoboot). The key_pressed() function is called from
2030 board_init(). Currently key_pressed() is a dummy
2031 function, returning 1 and thus enabling modem
2034 If there are no modem init strings in the
2035 environment, U-Boot proceed to autoboot; the
2036 previous output (banner, info printfs) will be
2039 See also: doc/README.Modem
2042 Configuration Settings:
2043 -----------------------
2045 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2046 undefine this when you're short of memory.
2048 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2049 width of the commands listed in the 'help' command output.
2051 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2052 prompt for user input.
2054 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2056 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2058 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2060 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2061 the application (usually a Linux kernel) when it is
2064 - CONFIG_SYS_BAUDRATE_TABLE:
2065 List of legal baudrate settings for this board.
2067 - CONFIG_SYS_CONSOLE_INFO_QUIET
2068 Suppress display of console information at boot.
2070 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2071 If the board specific function
2072 extern int overwrite_console (void);
2073 returns 1, the stdin, stderr and stdout are switched to the
2074 serial port, else the settings in the environment are used.
2076 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2077 Enable the call to overwrite_console().
2079 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2080 Enable overwrite of previous console environment settings.
2082 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2083 Begin and End addresses of the area used by the
2086 - CONFIG_SYS_ALT_MEMTEST:
2087 Enable an alternate, more extensive memory test.
2089 - CONFIG_SYS_MEMTEST_SCRATCH:
2090 Scratch address used by the alternate memory test
2091 You only need to set this if address zero isn't writeable
2093 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2094 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2095 this specified memory area will get subtracted from the top
2096 (end) of RAM and won't get "touched" at all by U-Boot. By
2097 fixing up gd->ram_size the Linux kernel should gets passed
2098 the now "corrected" memory size and won't touch it either.
2099 This should work for arch/ppc and arch/powerpc. Only Linux
2100 board ports in arch/powerpc with bootwrapper support that
2101 recalculate the memory size from the SDRAM controller setup
2102 will have to get fixed in Linux additionally.
2104 This option can be used as a workaround for the 440EPx/GRx
2105 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2108 WARNING: Please make sure that this value is a multiple of
2109 the Linux page size (normally 4k). If this is not the case,
2110 then the end address of the Linux memory will be located at a
2111 non page size aligned address and this could cause major
2114 - CONFIG_SYS_TFTP_LOADADDR:
2115 Default load address for network file downloads
2117 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2118 Enable temporary baudrate change while serial download
2120 - CONFIG_SYS_SDRAM_BASE:
2121 Physical start address of SDRAM. _Must_ be 0 here.
2123 - CONFIG_SYS_MBIO_BASE:
2124 Physical start address of Motherboard I/O (if using a
2127 - CONFIG_SYS_FLASH_BASE:
2128 Physical start address of Flash memory.
2130 - CONFIG_SYS_MONITOR_BASE:
2131 Physical start address of boot monitor code (set by
2132 make config files to be same as the text base address
2133 (TEXT_BASE) used when linking) - same as
2134 CONFIG_SYS_FLASH_BASE when booting from flash.
2136 - CONFIG_SYS_MONITOR_LEN:
2137 Size of memory reserved for monitor code, used to
2138 determine _at_compile_time_ (!) if the environment is
2139 embedded within the U-Boot image, or in a separate
2142 - CONFIG_SYS_MALLOC_LEN:
2143 Size of DRAM reserved for malloc() use.
2145 - CONFIG_SYS_BOOTM_LEN:
2146 Normally compressed uImages are limited to an
2147 uncompressed size of 8 MBytes. If this is not enough,
2148 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2149 to adjust this setting to your needs.
2151 - CONFIG_SYS_BOOTMAPSZ:
2152 Maximum size of memory mapped by the startup code of
2153 the Linux kernel; all data that must be processed by
2154 the Linux kernel (bd_info, boot arguments, FDT blob if
2155 used) must be put below this limit, unless "bootm_low"
2156 enviroment variable is defined and non-zero. In such case
2157 all data for the Linux kernel must be between "bootm_low"
2158 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2160 - CONFIG_SYS_MAX_FLASH_BANKS:
2161 Max number of Flash memory banks
2163 - CONFIG_SYS_MAX_FLASH_SECT:
2164 Max number of sectors on a Flash chip
2166 - CONFIG_SYS_FLASH_ERASE_TOUT:
2167 Timeout for Flash erase operations (in ms)
2169 - CONFIG_SYS_FLASH_WRITE_TOUT:
2170 Timeout for Flash write operations (in ms)
2172 - CONFIG_SYS_FLASH_LOCK_TOUT
2173 Timeout for Flash set sector lock bit operation (in ms)
2175 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2176 Timeout for Flash clear lock bits operation (in ms)
2178 - CONFIG_SYS_FLASH_PROTECTION
2179 If defined, hardware flash sectors protection is used
2180 instead of U-Boot software protection.
2182 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2184 Enable TFTP transfers directly to flash memory;
2185 without this option such a download has to be
2186 performed in two steps: (1) download to RAM, and (2)
2187 copy from RAM to flash.
2189 The two-step approach is usually more reliable, since
2190 you can check if the download worked before you erase
2191 the flash, but in some situations (when system RAM is
2192 too limited to allow for a temporary copy of the
2193 downloaded image) this option may be very useful.
2195 - CONFIG_SYS_FLASH_CFI:
2196 Define if the flash driver uses extra elements in the
2197 common flash structure for storing flash geometry.
2199 - CONFIG_FLASH_CFI_DRIVER
2200 This option also enables the building of the cfi_flash driver
2201 in the drivers directory
2203 - CONFIG_FLASH_CFI_MTD
2204 This option enables the building of the cfi_mtd driver
2205 in the drivers directory. The driver exports CFI flash
2208 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2209 Use buffered writes to flash.
2211 - CONFIG_FLASH_SPANSION_S29WS_N
2212 s29ws-n MirrorBit flash has non-standard addresses for buffered
2215 - CONFIG_SYS_FLASH_QUIET_TEST
2216 If this option is defined, the common CFI flash doesn't
2217 print it's warning upon not recognized FLASH banks. This
2218 is useful, if some of the configured banks are only
2219 optionally available.
2221 - CONFIG_FLASH_SHOW_PROGRESS
2222 If defined (must be an integer), print out countdown
2223 digits and dots. Recommended value: 45 (9..1) for 80
2224 column displays, 15 (3..1) for 40 column displays.
2226 - CONFIG_SYS_RX_ETH_BUFFER:
2227 Defines the number of Ethernet receive buffers. On some
2228 Ethernet controllers it is recommended to set this value
2229 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2230 buffers can be full shortly after enabling the interface
2231 on high Ethernet traffic.
2232 Defaults to 4 if not defined.
2234 The following definitions that deal with the placement and management
2235 of environment data (variable area); in general, we support the
2236 following configurations:
2238 - CONFIG_ENV_IS_IN_FLASH:
2240 Define this if the environment is in flash memory.
2242 a) The environment occupies one whole flash sector, which is
2243 "embedded" in the text segment with the U-Boot code. This
2244 happens usually with "bottom boot sector" or "top boot
2245 sector" type flash chips, which have several smaller
2246 sectors at the start or the end. For instance, such a
2247 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2248 such a case you would place the environment in one of the
2249 4 kB sectors - with U-Boot code before and after it. With
2250 "top boot sector" type flash chips, you would put the
2251 environment in one of the last sectors, leaving a gap
2252 between U-Boot and the environment.
2254 - CONFIG_ENV_OFFSET:
2256 Offset of environment data (variable area) to the
2257 beginning of flash memory; for instance, with bottom boot
2258 type flash chips the second sector can be used: the offset
2259 for this sector is given here.
2261 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2265 This is just another way to specify the start address of
2266 the flash sector containing the environment (instead of
2269 - CONFIG_ENV_SECT_SIZE:
2271 Size of the sector containing the environment.
2274 b) Sometimes flash chips have few, equal sized, BIG sectors.
2275 In such a case you don't want to spend a whole sector for
2280 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2281 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2282 of this flash sector for the environment. This saves
2283 memory for the RAM copy of the environment.
2285 It may also save flash memory if you decide to use this
2286 when your environment is "embedded" within U-Boot code,
2287 since then the remainder of the flash sector could be used
2288 for U-Boot code. It should be pointed out that this is
2289 STRONGLY DISCOURAGED from a robustness point of view:
2290 updating the environment in flash makes it always
2291 necessary to erase the WHOLE sector. If something goes
2292 wrong before the contents has been restored from a copy in
2293 RAM, your target system will be dead.
2295 - CONFIG_ENV_ADDR_REDUND
2296 CONFIG_ENV_SIZE_REDUND
2298 These settings describe a second storage area used to hold
2299 a redundant copy of the environment data, so that there is
2300 a valid backup copy in case there is a power failure during
2301 a "saveenv" operation.
2303 BE CAREFUL! Any changes to the flash layout, and some changes to the
2304 source code will make it necessary to adapt <board>/u-boot.lds*
2308 - CONFIG_ENV_IS_IN_NVRAM:
2310 Define this if you have some non-volatile memory device
2311 (NVRAM, battery buffered SRAM) which you want to use for the
2317 These two #defines are used to determine the memory area you
2318 want to use for environment. It is assumed that this memory
2319 can just be read and written to, without any special
2322 BE CAREFUL! The first access to the environment happens quite early
2323 in U-Boot initalization (when we try to get the setting of for the
2324 console baudrate). You *MUST* have mapped your NVRAM area then, or
2327 Please note that even with NVRAM we still use a copy of the
2328 environment in RAM: we could work on NVRAM directly, but we want to
2329 keep settings there always unmodified except somebody uses "saveenv"
2330 to save the current settings.
2333 - CONFIG_ENV_IS_IN_EEPROM:
2335 Use this if you have an EEPROM or similar serial access
2336 device and a driver for it.
2338 - CONFIG_ENV_OFFSET:
2341 These two #defines specify the offset and size of the
2342 environment area within the total memory of your EEPROM.
2344 - CONFIG_SYS_I2C_EEPROM_ADDR:
2345 If defined, specified the chip address of the EEPROM device.
2346 The default address is zero.
2348 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2349 If defined, the number of bits used to address bytes in a
2350 single page in the EEPROM device. A 64 byte page, for example
2351 would require six bits.
2353 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2354 If defined, the number of milliseconds to delay between
2355 page writes. The default is zero milliseconds.
2357 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2358 The length in bytes of the EEPROM memory array address. Note
2359 that this is NOT the chip address length!
2361 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2362 EEPROM chips that implement "address overflow" are ones
2363 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2364 address and the extra bits end up in the "chip address" bit
2365 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2368 Note that we consider the length of the address field to
2369 still be one byte because the extra address bits are hidden
2370 in the chip address.
2372 - CONFIG_SYS_EEPROM_SIZE:
2373 The size in bytes of the EEPROM device.
2376 - CONFIG_ENV_IS_IN_DATAFLASH:
2378 Define this if you have a DataFlash memory device which you
2379 want to use for the environment.
2381 - CONFIG_ENV_OFFSET:
2385 These three #defines specify the offset and size of the
2386 environment area within the total memory of your DataFlash placed
2387 at the specified address.
2389 - CONFIG_ENV_IS_IN_NAND:
2391 Define this if you have a NAND device which you want to use
2392 for the environment.
2394 - CONFIG_ENV_OFFSET:
2397 These two #defines specify the offset and size of the environment
2398 area within the first NAND device.
2400 - CONFIG_ENV_OFFSET_REDUND
2402 This setting describes a second storage area of CONFIG_ENV_SIZE
2403 size used to hold a redundant copy of the environment data,
2404 so that there is a valid backup copy in case there is a
2405 power failure during a "saveenv" operation.
2407 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2408 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2409 the NAND devices block size.
2411 - CONFIG_SYS_SPI_INIT_OFFSET
2413 Defines offset to the initial SPI buffer area in DPRAM. The
2414 area is used at an early stage (ROM part) if the environment
2415 is configured to reside in the SPI EEPROM: We need a 520 byte
2416 scratch DPRAM area. It is used between the two initialization
2417 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2418 to be a good choice since it makes it far enough from the
2419 start of the data area as well as from the stack pointer.
2421 Please note that the environment is read-only until the monitor
2422 has been relocated to RAM and a RAM copy of the environment has been
2423 created; also, when using EEPROM you will have to use getenv_r()
2424 until then to read environment variables.
2426 The environment is protected by a CRC32 checksum. Before the monitor
2427 is relocated into RAM, as a result of a bad CRC you will be working
2428 with the compiled-in default environment - *silently*!!! [This is
2429 necessary, because the first environment variable we need is the
2430 "baudrate" setting for the console - if we have a bad CRC, we don't
2431 have any device yet where we could complain.]
2433 Note: once the monitor has been relocated, then it will complain if
2434 the default environment is used; a new CRC is computed as soon as you
2435 use the "saveenv" command to store a valid environment.
2437 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2438 Echo the inverted Ethernet link state to the fault LED.
2440 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2441 also needs to be defined.
2443 - CONFIG_SYS_FAULT_MII_ADDR:
2444 MII address of the PHY to check for the Ethernet link state.
2446 - CONFIG_SYS_64BIT_VSPRINTF:
2447 Makes vsprintf (and all *printf functions) support printing
2448 of 64bit values by using the L quantifier
2450 - CONFIG_SYS_64BIT_STRTOUL:
2451 Adds simple_strtoull that returns a 64bit value
2453 Low Level (hardware related) configuration options:
2454 ---------------------------------------------------
2456 - CONFIG_SYS_CACHELINE_SIZE:
2457 Cache Line Size of the CPU.
2459 - CONFIG_SYS_DEFAULT_IMMR:
2460 Default address of the IMMR after system reset.
2462 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2463 and RPXsuper) to be able to adjust the position of
2464 the IMMR register after a reset.
2466 - Floppy Disk Support:
2467 CONFIG_SYS_FDC_DRIVE_NUMBER
2469 the default drive number (default value 0)
2471 CONFIG_SYS_ISA_IO_STRIDE
2473 defines the spacing between FDC chipset registers
2476 CONFIG_SYS_ISA_IO_OFFSET
2478 defines the offset of register from address. It
2479 depends on which part of the data bus is connected to
2480 the FDC chipset. (default value 0)
2482 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2483 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2486 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2487 fdc_hw_init() is called at the beginning of the FDC
2488 setup. fdc_hw_init() must be provided by the board
2489 source code. It is used to make hardware dependant
2492 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2493 DO NOT CHANGE unless you know exactly what you're
2494 doing! (11-4) [MPC8xx/82xx systems only]
2496 - CONFIG_SYS_INIT_RAM_ADDR:
2498 Start address of memory area that can be used for
2499 initial data and stack; please note that this must be
2500 writable memory that is working WITHOUT special
2501 initialization, i. e. you CANNOT use normal RAM which
2502 will become available only after programming the
2503 memory controller and running certain initialization
2506 U-Boot uses the following memory types:
2507 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2508 - MPC824X: data cache
2509 - PPC4xx: data cache
2511 - CONFIG_SYS_GBL_DATA_OFFSET:
2513 Offset of the initial data structure in the memory
2514 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2515 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2516 data is located at the end of the available space
2517 (sometimes written as (CONFIG_SYS_INIT_RAM_END -
2518 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2519 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2520 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2523 On the MPC824X (or other systems that use the data
2524 cache for initial memory) the address chosen for
2525 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2526 point to an otherwise UNUSED address space between
2527 the top of RAM and the start of the PCI space.
2529 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2531 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2533 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2535 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2537 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2539 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2541 - CONFIG_SYS_OR_TIMING_SDRAM:
2544 - CONFIG_SYS_MAMR_PTA:
2545 periodic timer for refresh
2547 - CONFIG_SYS_DER: Debug Event Register (37-47)
2549 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2550 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2551 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2552 CONFIG_SYS_BR1_PRELIM:
2553 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2555 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2556 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2557 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2558 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2560 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2561 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2562 Machine Mode Register and Memory Periodic Timer
2563 Prescaler definitions (SDRAM timing)
2565 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2566 enable I2C microcode relocation patch (MPC8xx);
2567 define relocation offset in DPRAM [DSP2]
2569 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2570 enable SMC microcode relocation patch (MPC8xx);
2571 define relocation offset in DPRAM [SMC1]
2573 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2574 enable SPI microcode relocation patch (MPC8xx);
2575 define relocation offset in DPRAM [SCC4]
2577 - CONFIG_SYS_USE_OSCCLK:
2578 Use OSCM clock mode on MBX8xx board. Be careful,
2579 wrong setting might damage your board. Read
2580 doc/README.MBX before setting this variable!
2582 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2583 Offset of the bootmode word in DPRAM used by post
2584 (Power On Self Tests). This definition overrides
2585 #define'd default value in commproc.h resp.
2588 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2589 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2590 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2591 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2592 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2593 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2594 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2595 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2596 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2599 Get DDR timing information from an I2C EEPROM. Common
2600 with pluggable memory modules such as SODIMMs
2603 I2C address of the SPD EEPROM
2605 - CONFIG_SYS_SPD_BUS_NUM
2606 If SPD EEPROM is on an I2C bus other than the first
2607 one, specify here. Note that the value must resolve
2608 to something your driver can deal with.
2610 - CONFIG_SYS_83XX_DDR_USES_CS0
2611 Only for 83xx systems. If specified, then DDR should
2612 be configured using CS0 and CS1 instead of CS2 and CS3.
2614 - CONFIG_SYS_83XX_DDR_USES_CS0
2615 Only for 83xx systems. If specified, then DDR should
2616 be configured using CS0 and CS1 instead of CS2 and CS3.
2618 - CONFIG_ETHER_ON_FEC[12]
2619 Define to enable FEC[12] on a 8xx series processor.
2621 - CONFIG_FEC[12]_PHY
2622 Define to the hardcoded PHY address which corresponds
2623 to the given FEC; i. e.
2624 #define CONFIG_FEC1_PHY 4
2625 means that the PHY with address 4 is connected to FEC1
2627 When set to -1, means to probe for first available.
2629 - CONFIG_FEC[12]_PHY_NORXERR
2630 The PHY does not have a RXERR line (RMII only).
2631 (so program the FEC to ignore it).
2634 Enable RMII mode for all FECs.
2635 Note that this is a global option, we can't
2636 have one FEC in standard MII mode and another in RMII mode.
2638 - CONFIG_CRC32_VERIFY
2639 Add a verify option to the crc32 command.
2642 => crc32 -v <address> <count> <crc32>
2644 Where address/count indicate a memory area
2645 and crc32 is the correct crc32 which the
2649 Add the "loopw" memory command. This only takes effect if
2650 the memory commands are activated globally (CONFIG_CMD_MEM).
2653 Add the "mdc" and "mwc" memory commands. These are cyclic
2658 This command will print 4 bytes (10,11,12,13) each 500 ms.
2660 => mwc.l 100 12345678 10
2661 This command will write 12345678 to address 100 all 10 ms.
2663 This only takes effect if the memory commands are activated
2664 globally (CONFIG_CMD_MEM).
2666 - CONFIG_SKIP_LOWLEVEL_INIT
2667 - CONFIG_SKIP_RELOCATE_UBOOT
2669 [ARM only] If these variables are defined, then
2670 certain low level initializations (like setting up
2671 the memory controller) are omitted and/or U-Boot does
2672 not relocate itself into RAM.
2673 Normally these variables MUST NOT be defined. The
2674 only exception is when U-Boot is loaded (to RAM) by
2675 some other boot loader or by a debugger which
2676 performs these initializations itself.
2679 Building the Software:
2680 ======================
2682 Building U-Boot has been tested in several native build environments
2683 and in many different cross environments. Of course we cannot support
2684 all possibly existing versions of cross development tools in all
2685 (potentially obsolete) versions. In case of tool chain problems we
2686 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2687 which is extensively used to build and test U-Boot.
2689 If you are not using a native environment, it is assumed that you
2690 have GNU cross compiling tools available in your path. In this case,
2691 you must set the environment variable CROSS_COMPILE in your shell.
2692 Note that no changes to the Makefile or any other source files are
2693 necessary. For example using the ELDK on a 4xx CPU, please enter:
2695 $ CROSS_COMPILE=ppc_4xx-
2696 $ export CROSS_COMPILE
2698 U-Boot is intended to be simple to build. After installing the
2699 sources you must configure U-Boot for one specific board type. This
2704 where "NAME_config" is the name of one of the existing configu-
2705 rations; see the main Makefile for supported names.
2707 Note: for some board special configuration names may exist; check if
2708 additional information is available from the board vendor; for
2709 instance, the TQM823L systems are available without (standard)
2710 or with LCD support. You can select such additional "features"
2711 when choosing the configuration, i. e.
2714 - will configure for a plain TQM823L, i. e. no LCD support
2716 make TQM823L_LCD_config
2717 - will configure for a TQM823L with U-Boot console on LCD
2722 Finally, type "make all", and you should get some working U-Boot
2723 images ready for download to / installation on your system:
2725 - "u-boot.bin" is a raw binary image
2726 - "u-boot" is an image in ELF binary format
2727 - "u-boot.srec" is in Motorola S-Record format
2729 By default the build is performed locally and the objects are saved
2730 in the source directory. One of the two methods can be used to change
2731 this behavior and build U-Boot to some external directory:
2733 1. Add O= to the make command line invocations:
2735 make O=/tmp/build distclean
2736 make O=/tmp/build NAME_config
2737 make O=/tmp/build all
2739 2. Set environment variable BUILD_DIR to point to the desired location:
2741 export BUILD_DIR=/tmp/build
2746 Note that the command line "O=" setting overrides the BUILD_DIR environment
2750 Please be aware that the Makefiles assume you are using GNU make, so
2751 for instance on NetBSD you might need to use "gmake" instead of
2755 If the system board that you have is not listed, then you will need
2756 to port U-Boot to your hardware platform. To do this, follow these
2759 1. Add a new configuration option for your board to the toplevel
2760 "Makefile" and to the "MAKEALL" script, using the existing
2761 entries as examples. Note that here and at many other places
2762 boards and other names are listed in alphabetical sort order. Please
2764 2. Create a new directory to hold your board specific code. Add any
2765 files you need. In your board directory, you will need at least
2766 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2767 3. Create a new configuration file "include/configs/<board>.h" for
2769 3. If you're porting U-Boot to a new CPU, then also create a new
2770 directory to hold your CPU specific code. Add any files you need.
2771 4. Run "make <board>_config" with your new name.
2772 5. Type "make", and you should get a working "u-boot.srec" file
2773 to be installed on your target system.
2774 6. Debug and solve any problems that might arise.
2775 [Of course, this last step is much harder than it sounds.]
2778 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2779 ==============================================================
2781 If you have modified U-Boot sources (for instance added a new board
2782 or support for new devices, a new CPU, etc.) you are expected to
2783 provide feedback to the other developers. The feedback normally takes
2784 the form of a "patch", i. e. a context diff against a certain (latest
2785 official or latest in the git repository) version of U-Boot sources.
2787 But before you submit such a patch, please verify that your modifi-
2788 cation did not break existing code. At least make sure that *ALL* of
2789 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2790 just run the "MAKEALL" script, which will configure and build U-Boot
2791 for ALL supported system. Be warned, this will take a while. You can
2792 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2793 environment variable to the script, i. e. to use the ELDK cross tools
2796 CROSS_COMPILE=ppc_8xx- MAKEALL
2798 or to build on a native PowerPC system you can type
2800 CROSS_COMPILE=' ' MAKEALL
2802 When using the MAKEALL script, the default behaviour is to build
2803 U-Boot in the source directory. This location can be changed by
2804 setting the BUILD_DIR environment variable. Also, for each target
2805 built, the MAKEALL script saves two log files (<target>.ERR and
2806 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2807 location can be changed by setting the MAKEALL_LOGDIR environment
2808 variable. For example:
2810 export BUILD_DIR=/tmp/build
2811 export MAKEALL_LOGDIR=/tmp/log
2812 CROSS_COMPILE=ppc_8xx- MAKEALL
2814 With the above settings build objects are saved in the /tmp/build,
2815 log files are saved in the /tmp/log and the source tree remains clean
2816 during the whole build process.
2819 See also "U-Boot Porting Guide" below.
2822 Monitor Commands - Overview:
2823 ============================
2825 go - start application at address 'addr'
2826 run - run commands in an environment variable
2827 bootm - boot application image from memory
2828 bootp - boot image via network using BootP/TFTP protocol
2829 tftpboot- boot image via network using TFTP protocol
2830 and env variables "ipaddr" and "serverip"
2831 (and eventually "gatewayip")
2832 rarpboot- boot image via network using RARP/TFTP protocol
2833 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2834 loads - load S-Record file over serial line
2835 loadb - load binary file over serial line (kermit mode)
2837 mm - memory modify (auto-incrementing)
2838 nm - memory modify (constant address)
2839 mw - memory write (fill)
2841 cmp - memory compare
2842 crc32 - checksum calculation
2843 imd - i2c memory display
2844 imm - i2c memory modify (auto-incrementing)
2845 inm - i2c memory modify (constant address)
2846 imw - i2c memory write (fill)
2847 icrc32 - i2c checksum calculation
2848 iprobe - probe to discover valid I2C chip addresses
2849 iloop - infinite loop on address range
2850 isdram - print SDRAM configuration information
2851 sspi - SPI utility commands
2852 base - print or set address offset
2853 printenv- print environment variables
2854 setenv - set environment variables
2855 saveenv - save environment variables to persistent storage
2856 protect - enable or disable FLASH write protection
2857 erase - erase FLASH memory
2858 flinfo - print FLASH memory information
2859 bdinfo - print Board Info structure
2860 iminfo - print header information for application image
2861 coninfo - print console devices and informations
2862 ide - IDE sub-system
2863 loop - infinite loop on address range
2864 loopw - infinite write loop on address range
2865 mtest - simple RAM test
2866 icache - enable or disable instruction cache
2867 dcache - enable or disable data cache
2868 reset - Perform RESET of the CPU
2869 echo - echo args to console
2870 version - print monitor version
2871 help - print online help
2872 ? - alias for 'help'
2875 Monitor Commands - Detailed Description:
2876 ========================================
2880 For now: just type "help <command>".
2883 Environment Variables:
2884 ======================
2886 U-Boot supports user configuration using Environment Variables which
2887 can be made persistent by saving to Flash memory.
2889 Environment Variables are set using "setenv", printed using
2890 "printenv", and saved to Flash using "saveenv". Using "setenv"
2891 without a value can be used to delete a variable from the
2892 environment. As long as you don't save the environment you are
2893 working with an in-memory copy. In case the Flash area containing the
2894 environment is erased by accident, a default environment is provided.
2896 Some configuration options can be set using Environment Variables:
2898 baudrate - see CONFIG_BAUDRATE
2900 bootdelay - see CONFIG_BOOTDELAY
2902 bootcmd - see CONFIG_BOOTCOMMAND
2904 bootargs - Boot arguments when booting an RTOS image
2906 bootfile - Name of the image to load with TFTP
2908 bootm_low - Memory range available for image processing in the bootm
2909 command can be restricted. This variable is given as
2910 a hexadecimal number and defines lowest address allowed
2911 for use by the bootm command. See also "bootm_size"
2912 environment variable. Address defined by "bootm_low" is
2913 also the base of the initial memory mapping for the Linux
2914 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
2916 bootm_size - Memory range available for image processing in the bootm
2917 command can be restricted. This variable is given as
2918 a hexadecimal number and defines the size of the region
2919 allowed for use by the bootm command. See also "bootm_low"
2920 environment variable.
2922 updatefile - Location of the software update file on a TFTP server, used
2923 by the automatic software update feature. Please refer to
2924 documentation in doc/README.update for more details.
2926 autoload - if set to "no" (any string beginning with 'n'),
2927 "bootp" will just load perform a lookup of the
2928 configuration from the BOOTP server, but not try to
2929 load any image using TFTP
2931 autoscript - if set to "yes" commands like "loadb", "loady",
2932 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2933 to automatically run script images (by internally
2934 calling "autoscript").
2936 autoscript_uname - if script image is in a format (FIT) this
2937 variable is used to get script subimage unit name.
2939 autostart - if set to "yes", an image loaded using the "bootp",
2940 "rarpboot", "tftpboot" or "diskboot" commands will
2941 be automatically started (by internally calling
2944 If set to "no", a standalone image passed to the
2945 "bootm" command will be copied to the load address
2946 (and eventually uncompressed), but NOT be started.
2947 This can be used to load and uncompress arbitrary
2950 i2cfast - (PPC405GP|PPC405EP only)
2951 if set to 'y' configures Linux I2C driver for fast
2952 mode (400kHZ). This environment variable is used in
2953 initialization code. So, for changes to be effective
2954 it must be saved and board must be reset.
2956 initrd_high - restrict positioning of initrd images:
2957 If this variable is not set, initrd images will be
2958 copied to the highest possible address in RAM; this
2959 is usually what you want since it allows for
2960 maximum initrd size. If for some reason you want to
2961 make sure that the initrd image is loaded below the
2962 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
2963 variable to a value of "no" or "off" or "0".
2964 Alternatively, you can set it to a maximum upper
2965 address to use (U-Boot will still check that it
2966 does not overwrite the U-Boot stack and data).
2968 For instance, when you have a system with 16 MB
2969 RAM, and want to reserve 4 MB from use by Linux,
2970 you can do this by adding "mem=12M" to the value of
2971 the "bootargs" variable. However, now you must make
2972 sure that the initrd image is placed in the first
2973 12 MB as well - this can be done with
2975 setenv initrd_high 00c00000
2977 If you set initrd_high to 0xFFFFFFFF, this is an
2978 indication to U-Boot that all addresses are legal
2979 for the Linux kernel, including addresses in flash
2980 memory. In this case U-Boot will NOT COPY the
2981 ramdisk at all. This may be useful to reduce the
2982 boot time on your system, but requires that this
2983 feature is supported by your Linux kernel.
2985 ipaddr - IP address; needed for tftpboot command
2987 loadaddr - Default load address for commands like "bootp",
2988 "rarpboot", "tftpboot", "loadb" or "diskboot"
2990 loads_echo - see CONFIG_LOADS_ECHO
2992 serverip - TFTP server IP address; needed for tftpboot command
2994 bootretry - see CONFIG_BOOT_RETRY_TIME
2996 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2998 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3000 ethprime - When CONFIG_NET_MULTI is enabled controls which
3001 interface is used first.
3003 ethact - When CONFIG_NET_MULTI is enabled controls which
3004 interface is currently active. For example you
3005 can do the following
3007 => setenv ethact FEC ETHERNET
3008 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
3009 => setenv ethact SCC ETHERNET
3010 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
3012 ethrotate - When set to "no" U-Boot does not go through all
3013 available network interfaces.
3014 It just stays at the currently selected interface.
3016 netretry - When set to "no" each network operation will
3017 either succeed or fail without retrying.
3018 When set to "once" the network operation will
3019 fail when all the available network interfaces
3020 are tried once without success.
3021 Useful on scripts which control the retry operation
3024 npe_ucode - set load address for the NPE microcode
3026 tftpsrcport - If this is set, the value is used for TFTP's
3029 tftpdstport - If this is set, the value is used for TFTP's UDP
3030 destination port instead of the Well Know Port 69.
3032 vlan - When set to a value < 4095 the traffic over
3033 Ethernet is encapsulated/received over 802.1q
3036 The following environment variables may be used and automatically
3037 updated by the network boot commands ("bootp" and "rarpboot"),
3038 depending the information provided by your boot server:
3040 bootfile - see above
3041 dnsip - IP address of your Domain Name Server
3042 dnsip2 - IP address of your secondary Domain Name Server
3043 gatewayip - IP address of the Gateway (Router) to use
3044 hostname - Target hostname
3046 netmask - Subnet Mask
3047 rootpath - Pathname of the root filesystem on the NFS server
3048 serverip - see above
3051 There are two special Environment Variables:
3053 serial# - contains hardware identification information such
3054 as type string and/or serial number
3055 ethaddr - Ethernet address
3057 These variables can be set only once (usually during manufacturing of
3058 the board). U-Boot refuses to delete or overwrite these variables
3059 once they have been set once.
3062 Further special Environment Variables:
3064 ver - Contains the U-Boot version string as printed
3065 with the "version" command. This variable is
3066 readonly (see CONFIG_VERSION_VARIABLE).
3069 Please note that changes to some configuration parameters may take
3070 only effect after the next boot (yes, that's just like Windoze :-).
3073 Command Line Parsing:
3074 =====================
3076 There are two different command line parsers available with U-Boot:
3077 the old "simple" one, and the much more powerful "hush" shell:
3079 Old, simple command line parser:
3080 --------------------------------
3082 - supports environment variables (through setenv / saveenv commands)
3083 - several commands on one line, separated by ';'
3084 - variable substitution using "... ${name} ..." syntax
3085 - special characters ('$', ';') can be escaped by prefixing with '\',
3087 setenv bootcmd bootm \${address}
3088 - You can also escape text by enclosing in single apostrophes, for example:
3089 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3094 - similar to Bourne shell, with control structures like
3095 if...then...else...fi, for...do...done; while...do...done,
3096 until...do...done, ...
3097 - supports environment ("global") variables (through setenv / saveenv
3098 commands) and local shell variables (through standard shell syntax
3099 "name=value"); only environment variables can be used with "run"
3105 (1) If a command line (or an environment variable executed by a "run"
3106 command) contains several commands separated by semicolon, and
3107 one of these commands fails, then the remaining commands will be
3110 (2) If you execute several variables with one call to run (i. e.
3111 calling run with a list of variables as arguments), any failing
3112 command will cause "run" to terminate, i. e. the remaining
3113 variables are not executed.
3115 Note for Redundant Ethernet Interfaces:
3116 =======================================
3118 Some boards come with redundant Ethernet interfaces; U-Boot supports
3119 such configurations and is capable of automatic selection of a
3120 "working" interface when needed. MAC assignment works as follows:
3122 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3123 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3124 "eth1addr" (=>eth1), "eth2addr", ...
3126 If the network interface stores some valid MAC address (for instance
3127 in SROM), this is used as default address if there is NO correspon-
3128 ding setting in the environment; if the corresponding environment
3129 variable is set, this overrides the settings in the card; that means:
3131 o If the SROM has a valid MAC address, and there is no address in the
3132 environment, the SROM's address is used.
3134 o If there is no valid address in the SROM, and a definition in the
3135 environment exists, then the value from the environment variable is
3138 o If both the SROM and the environment contain a MAC address, and
3139 both addresses are the same, this MAC address is used.
3141 o If both the SROM and the environment contain a MAC address, and the
3142 addresses differ, the value from the environment is used and a
3145 o If neither SROM nor the environment contain a MAC address, an error
3152 U-Boot is capable of booting (and performing other auxiliary operations on)
3153 images in two formats:
3155 New uImage format (FIT)
3156 -----------------------
3158 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3159 to Flattened Device Tree). It allows the use of images with multiple
3160 components (several kernels, ramdisks, etc.), with contents protected by
3161 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3167 Old image format is based on binary files which can be basically anything,
3168 preceded by a special header; see the definitions in include/image.h for
3169 details; basically, the header defines the following image properties:
3171 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3172 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3173 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3174 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3176 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3177 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3178 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3179 * Compression Type (uncompressed, gzip, bzip2)
3185 The header is marked by a special Magic Number, and both the header
3186 and the data portions of the image are secured against corruption by
3193 Although U-Boot should support any OS or standalone application
3194 easily, the main focus has always been on Linux during the design of
3197 U-Boot includes many features that so far have been part of some
3198 special "boot loader" code within the Linux kernel. Also, any
3199 "initrd" images to be used are no longer part of one big Linux image;
3200 instead, kernel and "initrd" are separate images. This implementation
3201 serves several purposes:
3203 - the same features can be used for other OS or standalone
3204 applications (for instance: using compressed images to reduce the
3205 Flash memory footprint)
3207 - it becomes much easier to port new Linux kernel versions because
3208 lots of low-level, hardware dependent stuff are done by U-Boot
3210 - the same Linux kernel image can now be used with different "initrd"
3211 images; of course this also means that different kernel images can
3212 be run with the same "initrd". This makes testing easier (you don't
3213 have to build a new "zImage.initrd" Linux image when you just
3214 change a file in your "initrd"). Also, a field-upgrade of the
3215 software is easier now.
3221 Porting Linux to U-Boot based systems:
3222 ---------------------------------------
3224 U-Boot cannot save you from doing all the necessary modifications to
3225 configure the Linux device drivers for use with your target hardware
3226 (no, we don't intend to provide a full virtual machine interface to
3229 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3231 Just make sure your machine specific header file (for instance
3232 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3233 Information structure as we define in include/asm-<arch>/u-boot.h,
3234 and make sure that your definition of IMAP_ADDR uses the same value
3235 as your U-Boot configuration in CONFIG_SYS_IMMR.
3238 Configuring the Linux kernel:
3239 -----------------------------
3241 No specific requirements for U-Boot. Make sure you have some root
3242 device (initial ramdisk, NFS) for your target system.
3245 Building a Linux Image:
3246 -----------------------
3248 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3249 not used. If you use recent kernel source, a new build target
3250 "uImage" will exist which automatically builds an image usable by
3251 U-Boot. Most older kernels also have support for a "pImage" target,
3252 which was introduced for our predecessor project PPCBoot and uses a
3253 100% compatible format.
3262 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3263 encapsulate a compressed Linux kernel image with header information,
3264 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3266 * build a standard "vmlinux" kernel image (in ELF binary format):
3268 * convert the kernel into a raw binary image:
3270 ${CROSS_COMPILE}-objcopy -O binary \
3271 -R .note -R .comment \
3272 -S vmlinux linux.bin
3274 * compress the binary image:
3278 * package compressed binary image for U-Boot:
3280 mkimage -A ppc -O linux -T kernel -C gzip \
3281 -a 0 -e 0 -n "Linux Kernel Image" \
3282 -d linux.bin.gz uImage
3285 The "mkimage" tool can also be used to create ramdisk images for use
3286 with U-Boot, either separated from the Linux kernel image, or
3287 combined into one file. "mkimage" encapsulates the images with a 64
3288 byte header containing information about target architecture,
3289 operating system, image type, compression method, entry points, time
3290 stamp, CRC32 checksums, etc.
3292 "mkimage" can be called in two ways: to verify existing images and
3293 print the header information, or to build new images.
3295 In the first form (with "-l" option) mkimage lists the information
3296 contained in the header of an existing U-Boot image; this includes
3297 checksum verification:
3299 tools/mkimage -l image
3300 -l ==> list image header information
3302 The second form (with "-d" option) is used to build a U-Boot image
3303 from a "data file" which is used as image payload:
3305 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3306 -n name -d data_file image
3307 -A ==> set architecture to 'arch'
3308 -O ==> set operating system to 'os'
3309 -T ==> set image type to 'type'
3310 -C ==> set compression type 'comp'
3311 -a ==> set load address to 'addr' (hex)
3312 -e ==> set entry point to 'ep' (hex)
3313 -n ==> set image name to 'name'
3314 -d ==> use image data from 'datafile'
3316 Right now, all Linux kernels for PowerPC systems use the same load
3317 address (0x00000000), but the entry point address depends on the
3320 - 2.2.x kernels have the entry point at 0x0000000C,
3321 - 2.3.x and later kernels have the entry point at 0x00000000.
3323 So a typical call to build a U-Boot image would read:
3325 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3326 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3327 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3328 > examples/uImage.TQM850L
3329 Image Name: 2.4.4 kernel for TQM850L
3330 Created: Wed Jul 19 02:34:59 2000
3331 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3332 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3333 Load Address: 0x00000000
3334 Entry Point: 0x00000000
3336 To verify the contents of the image (or check for corruption):
3338 -> tools/mkimage -l examples/uImage.TQM850L
3339 Image Name: 2.4.4 kernel for TQM850L
3340 Created: Wed Jul 19 02:34:59 2000
3341 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3342 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3343 Load Address: 0x00000000
3344 Entry Point: 0x00000000
3346 NOTE: for embedded systems where boot time is critical you can trade
3347 speed for memory and install an UNCOMPRESSED image instead: this
3348 needs more space in Flash, but boots much faster since it does not
3349 need to be uncompressed:
3351 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3352 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3353 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3354 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3355 > examples/uImage.TQM850L-uncompressed
3356 Image Name: 2.4.4 kernel for TQM850L
3357 Created: Wed Jul 19 02:34:59 2000
3358 Image Type: PowerPC Linux Kernel Image (uncompressed)
3359 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3360 Load Address: 0x00000000
3361 Entry Point: 0x00000000
3364 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3365 when your kernel is intended to use an initial ramdisk:
3367 -> tools/mkimage -n 'Simple Ramdisk Image' \
3368 > -A ppc -O linux -T ramdisk -C gzip \
3369 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3370 Image Name: Simple Ramdisk Image
3371 Created: Wed Jan 12 14:01:50 2000
3372 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3373 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3374 Load Address: 0x00000000
3375 Entry Point: 0x00000000
3378 Installing a Linux Image:
3379 -------------------------
3381 To downloading a U-Boot image over the serial (console) interface,
3382 you must convert the image to S-Record format:
3384 objcopy -I binary -O srec examples/image examples/image.srec
3386 The 'objcopy' does not understand the information in the U-Boot
3387 image header, so the resulting S-Record file will be relative to
3388 address 0x00000000. To load it to a given address, you need to
3389 specify the target address as 'offset' parameter with the 'loads'
3392 Example: install the image to address 0x40100000 (which on the
3393 TQM8xxL is in the first Flash bank):
3395 => erase 40100000 401FFFFF
3401 ## Ready for S-Record download ...
3402 ~>examples/image.srec
3403 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3405 15989 15990 15991 15992
3406 [file transfer complete]
3408 ## Start Addr = 0x00000000
3411 You can check the success of the download using the 'iminfo' command;
3412 this includes a checksum verification so you can be sure no data
3413 corruption happened:
3417 ## Checking Image at 40100000 ...
3418 Image Name: 2.2.13 for initrd on TQM850L
3419 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3420 Data Size: 335725 Bytes = 327 kB = 0 MB
3421 Load Address: 00000000
3422 Entry Point: 0000000c
3423 Verifying Checksum ... OK
3429 The "bootm" command is used to boot an application that is stored in
3430 memory (RAM or Flash). In case of a Linux kernel image, the contents
3431 of the "bootargs" environment variable is passed to the kernel as
3432 parameters. You can check and modify this variable using the
3433 "printenv" and "setenv" commands:
3436 => printenv bootargs
3437 bootargs=root=/dev/ram
3439 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3441 => printenv bootargs
3442 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3445 ## Booting Linux kernel at 40020000 ...
3446 Image Name: 2.2.13 for NFS on TQM850L
3447 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3448 Data Size: 381681 Bytes = 372 kB = 0 MB
3449 Load Address: 00000000
3450 Entry Point: 0000000c
3451 Verifying Checksum ... OK
3452 Uncompressing Kernel Image ... OK
3453 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
3454 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3455 time_init: decrementer frequency = 187500000/60
3456 Calibrating delay loop... 49.77 BogoMIPS
3457 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3460 If you want to boot a Linux kernel with initial RAM disk, you pass
3461 the memory addresses of both the kernel and the initrd image (PPBCOOT
3462 format!) to the "bootm" command:
3464 => imi 40100000 40200000
3466 ## Checking Image at 40100000 ...
3467 Image Name: 2.2.13 for initrd on TQM850L
3468 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3469 Data Size: 335725 Bytes = 327 kB = 0 MB
3470 Load Address: 00000000
3471 Entry Point: 0000000c
3472 Verifying Checksum ... OK
3474 ## Checking Image at 40200000 ...
3475 Image Name: Simple Ramdisk Image
3476 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3477 Data Size: 566530 Bytes = 553 kB = 0 MB
3478 Load Address: 00000000
3479 Entry Point: 00000000
3480 Verifying Checksum ... OK
3482 => bootm 40100000 40200000
3483 ## Booting Linux kernel at 40100000 ...
3484 Image Name: 2.2.13 for initrd on TQM850L
3485 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3486 Data Size: 335725 Bytes = 327 kB = 0 MB
3487 Load Address: 00000000
3488 Entry Point: 0000000c
3489 Verifying Checksum ... OK
3490 Uncompressing Kernel Image ... OK
3491 ## Loading RAMDisk Image at 40200000 ...
3492 Image Name: Simple Ramdisk Image
3493 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3494 Data Size: 566530 Bytes = 553 kB = 0 MB
3495 Load Address: 00000000
3496 Entry Point: 00000000
3497 Verifying Checksum ... OK
3498 Loading Ramdisk ... OK
3499 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
3500 Boot arguments: root=/dev/ram
3501 time_init: decrementer frequency = 187500000/60
3502 Calibrating delay loop... 49.77 BogoMIPS
3504 RAMDISK: Compressed image found at block 0
3505 VFS: Mounted root (ext2 filesystem).
3509 Boot Linux and pass a flat device tree:
3512 First, U-Boot must be compiled with the appropriate defines. See the section
3513 titled "Linux Kernel Interface" above for a more in depth explanation. The
3514 following is an example of how to start a kernel and pass an updated
3520 oft=oftrees/mpc8540ads.dtb
3521 => tftp $oftaddr $oft
3522 Speed: 1000, full duplex
3524 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3525 Filename 'oftrees/mpc8540ads.dtb'.
3526 Load address: 0x300000
3529 Bytes transferred = 4106 (100a hex)
3530 => tftp $loadaddr $bootfile
3531 Speed: 1000, full duplex
3533 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3535 Load address: 0x200000
3536 Loading:############
3538 Bytes transferred = 1029407 (fb51f hex)
3543 => bootm $loadaddr - $oftaddr
3544 ## Booting image at 00200000 ...
3545 Image Name: Linux-2.6.17-dirty
3546 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3547 Data Size: 1029343 Bytes = 1005.2 kB
3548 Load Address: 00000000
3549 Entry Point: 00000000
3550 Verifying Checksum ... OK
3551 Uncompressing Kernel Image ... OK
3552 Booting using flat device tree at 0x300000
3553 Using MPC85xx ADS machine description
3554 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3558 More About U-Boot Image Types:
3559 ------------------------------
3561 U-Boot supports the following image types:
3563 "Standalone Programs" are directly runnable in the environment
3564 provided by U-Boot; it is expected that (if they behave
3565 well) you can continue to work in U-Boot after return from
3566 the Standalone Program.
3567 "OS Kernel Images" are usually images of some Embedded OS which
3568 will take over control completely. Usually these programs
3569 will install their own set of exception handlers, device
3570 drivers, set up the MMU, etc. - this means, that you cannot
3571 expect to re-enter U-Boot except by resetting the CPU.
3572 "RAMDisk Images" are more or less just data blocks, and their
3573 parameters (address, size) are passed to an OS kernel that is
3575 "Multi-File Images" contain several images, typically an OS
3576 (Linux) kernel image and one or more data images like
3577 RAMDisks. This construct is useful for instance when you want
3578 to boot over the network using BOOTP etc., where the boot
3579 server provides just a single image file, but you want to get
3580 for instance an OS kernel and a RAMDisk image.
3582 "Multi-File Images" start with a list of image sizes, each
3583 image size (in bytes) specified by an "uint32_t" in network
3584 byte order. This list is terminated by an "(uint32_t)0".
3585 Immediately after the terminating 0 follow the images, one by
3586 one, all aligned on "uint32_t" boundaries (size rounded up to
3587 a multiple of 4 bytes).
3589 "Firmware Images" are binary images containing firmware (like
3590 U-Boot or FPGA images) which usually will be programmed to
3593 "Script files" are command sequences that will be executed by
3594 U-Boot's command interpreter; this feature is especially
3595 useful when you configure U-Boot to use a real shell (hush)
3596 as command interpreter.
3602 One of the features of U-Boot is that you can dynamically load and
3603 run "standalone" applications, which can use some resources of
3604 U-Boot like console I/O functions or interrupt services.
3606 Two simple examples are included with the sources:
3611 'examples/hello_world.c' contains a small "Hello World" Demo
3612 application; it is automatically compiled when you build U-Boot.
3613 It's configured to run at address 0x00040004, so you can play with it
3617 ## Ready for S-Record download ...
3618 ~>examples/hello_world.srec
3619 1 2 3 4 5 6 7 8 9 10 11 ...
3620 [file transfer complete]
3622 ## Start Addr = 0x00040004
3624 => go 40004 Hello World! This is a test.
3625 ## Starting application at 0x00040004 ...
3636 Hit any key to exit ...
3638 ## Application terminated, rc = 0x0
3640 Another example, which demonstrates how to register a CPM interrupt
3641 handler with the U-Boot code, can be found in 'examples/timer.c'.
3642 Here, a CPM timer is set up to generate an interrupt every second.
3643 The interrupt service routine is trivial, just printing a '.'
3644 character, but this is just a demo program. The application can be
3645 controlled by the following keys:
3647 ? - print current values og the CPM Timer registers
3648 b - enable interrupts and start timer
3649 e - stop timer and disable interrupts
3650 q - quit application
3653 ## Ready for S-Record download ...
3654 ~>examples/timer.srec
3655 1 2 3 4 5 6 7 8 9 10 11 ...
3656 [file transfer complete]
3658 ## Start Addr = 0x00040004
3661 ## Starting application at 0x00040004 ...
3664 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3667 [q, b, e, ?] Set interval 1000000 us
3670 [q, b, e, ?] ........
3671 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3674 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3677 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3680 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3682 [q, b, e, ?] ...Stopping timer
3684 [q, b, e, ?] ## Application terminated, rc = 0x0
3690 Over time, many people have reported problems when trying to use the
3691 "minicom" terminal emulation program for serial download. I (wd)
3692 consider minicom to be broken, and recommend not to use it. Under
3693 Unix, I recommend to use C-Kermit for general purpose use (and
3694 especially for kermit binary protocol download ("loadb" command), and
3695 use "cu" for S-Record download ("loads" command).
3697 Nevertheless, if you absolutely want to use it try adding this
3698 configuration to your "File transfer protocols" section:
3700 Name Program Name U/D FullScr IO-Red. Multi
3701 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3702 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3708 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3709 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3711 Building requires a cross environment; it is known to work on
3712 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3713 need gmake since the Makefiles are not compatible with BSD make).
3714 Note that the cross-powerpc package does not install include files;
3715 attempting to build U-Boot will fail because <machine/ansi.h> is
3716 missing. This file has to be installed and patched manually:
3718 # cd /usr/pkg/cross/powerpc-netbsd/include
3720 # ln -s powerpc machine
3721 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3722 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3724 Native builds *don't* work due to incompatibilities between native
3725 and U-Boot include files.
3727 Booting assumes that (the first part of) the image booted is a
3728 stage-2 loader which in turn loads and then invokes the kernel
3729 proper. Loader sources will eventually appear in the NetBSD source
3730 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3731 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3734 Implementation Internals:
3735 =========================
3737 The following is not intended to be a complete description of every
3738 implementation detail. However, it should help to understand the
3739 inner workings of U-Boot and make it easier to port it to custom
3743 Initial Stack, Global Data:
3744 ---------------------------
3746 The implementation of U-Boot is complicated by the fact that U-Boot
3747 starts running out of ROM (flash memory), usually without access to
3748 system RAM (because the memory controller is not initialized yet).
3749 This means that we don't have writable Data or BSS segments, and BSS
3750 is not initialized as zero. To be able to get a C environment working
3751 at all, we have to allocate at least a minimal stack. Implementation
3752 options for this are defined and restricted by the CPU used: Some CPU
3753 models provide on-chip memory (like the IMMR area on MPC8xx and
3754 MPC826x processors), on others (parts of) the data cache can be
3755 locked as (mis-) used as memory, etc.
3757 Chris Hallinan posted a good summary of these issues to the
3758 U-Boot mailing list:
3760 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3761 From: "Chris Hallinan" <clh@net1plus.com>
3762 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3765 Correct me if I'm wrong, folks, but the way I understand it
3766 is this: Using DCACHE as initial RAM for Stack, etc, does not
3767 require any physical RAM backing up the cache. The cleverness
3768 is that the cache is being used as a temporary supply of
3769 necessary storage before the SDRAM controller is setup. It's
3770 beyond the scope of this list to explain the details, but you
3771 can see how this works by studying the cache architecture and
3772 operation in the architecture and processor-specific manuals.
3774 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3775 is another option for the system designer to use as an
3776 initial stack/RAM area prior to SDRAM being available. Either
3777 option should work for you. Using CS 4 should be fine if your
3778 board designers haven't used it for something that would
3779 cause you grief during the initial boot! It is frequently not
3782 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3783 with your processor/board/system design. The default value
3784 you will find in any recent u-boot distribution in
3785 walnut.h should work for you. I'd set it to a value larger
3786 than your SDRAM module. If you have a 64MB SDRAM module, set
3787 it above 400_0000. Just make sure your board has no resources
3788 that are supposed to respond to that address! That code in
3789 start.S has been around a while and should work as is when
3790 you get the config right.
3795 It is essential to remember this, since it has some impact on the C
3796 code for the initialization procedures:
3798 * Initialized global data (data segment) is read-only. Do not attempt
3801 * Do not use any uninitialized global data (or implicitely initialized
3802 as zero data - BSS segment) at all - this is undefined, initiali-
3803 zation is performed later (when relocating to RAM).
3805 * Stack space is very limited. Avoid big data buffers or things like
3808 Having only the stack as writable memory limits means we cannot use
3809 normal global data to share information beween the code. But it
3810 turned out that the implementation of U-Boot can be greatly
3811 simplified by making a global data structure (gd_t) available to all
3812 functions. We could pass a pointer to this data as argument to _all_
3813 functions, but this would bloat the code. Instead we use a feature of
3814 the GCC compiler (Global Register Variables) to share the data: we
3815 place a pointer (gd) to the global data into a register which we
3816 reserve for this purpose.
3818 When choosing a register for such a purpose we are restricted by the
3819 relevant (E)ABI specifications for the current architecture, and by
3820 GCC's implementation.
3822 For PowerPC, the following registers have specific use:
3824 R2: reserved for system use
3825 R3-R4: parameter passing and return values
3826 R5-R10: parameter passing
3827 R13: small data area pointer
3831 (U-Boot also uses R14 as internal GOT pointer.)
3833 ==> U-Boot will use R2 to hold a pointer to the global data
3835 Note: on PPC, we could use a static initializer (since the
3836 address of the global data structure is known at compile time),
3837 but it turned out that reserving a register results in somewhat
3838 smaller code - although the code savings are not that big (on
3839 average for all boards 752 bytes for the whole U-Boot image,
3840 624 text + 127 data).
3842 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3843 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3845 ==> U-Boot will use P5 to hold a pointer to the global data
3847 On ARM, the following registers are used:
3849 R0: function argument word/integer result
3850 R1-R3: function argument word
3852 R10: stack limit (used only if stack checking if enabled)
3853 R11: argument (frame) pointer
3854 R12: temporary workspace
3857 R15: program counter
3859 ==> U-Boot will use R8 to hold a pointer to the global data
3861 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3862 or current versions of GCC may "optimize" the code too much.
3867 U-Boot runs in system state and uses physical addresses, i.e. the
3868 MMU is not used either for address mapping nor for memory protection.
3870 The available memory is mapped to fixed addresses using the memory
3871 controller. In this process, a contiguous block is formed for each
3872 memory type (Flash, SDRAM, SRAM), even when it consists of several
3873 physical memory banks.
3875 U-Boot is installed in the first 128 kB of the first Flash bank (on
3876 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3877 booting and sizing and initializing DRAM, the code relocates itself
3878 to the upper end of DRAM. Immediately below the U-Boot code some
3879 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3880 configuration setting]. Below that, a structure with global Board
3881 Info data is placed, followed by the stack (growing downward).
3883 Additionally, some exception handler code is copied to the low 8 kB
3884 of DRAM (0x00000000 ... 0x00001FFF).
3886 So a typical memory configuration with 16 MB of DRAM could look like
3889 0x0000 0000 Exception Vector code
3892 0x0000 2000 Free for Application Use
3898 0x00FB FF20 Monitor Stack (Growing downward)
3899 0x00FB FFAC Board Info Data and permanent copy of global data
3900 0x00FC 0000 Malloc Arena
3903 0x00FE 0000 RAM Copy of Monitor Code
3904 ... eventually: LCD or video framebuffer
3905 ... eventually: pRAM (Protected RAM - unchanged by reset)
3906 0x00FF FFFF [End of RAM]
3909 System Initialization:
3910 ----------------------
3912 In the reset configuration, U-Boot starts at the reset entry point
3913 (on most PowerPC systems at address 0x00000100). Because of the reset
3914 configuration for CS0# this is a mirror of the onboard Flash memory.
3915 To be able to re-map memory U-Boot then jumps to its link address.
3916 To be able to implement the initialization code in C, a (small!)
3917 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3918 which provide such a feature like MPC8xx or MPC8260), or in a locked
3919 part of the data cache. After that, U-Boot initializes the CPU core,
3920 the caches and the SIU.
3922 Next, all (potentially) available memory banks are mapped using a
3923 preliminary mapping. For example, we put them on 512 MB boundaries
3924 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3925 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3926 programmed for SDRAM access. Using the temporary configuration, a
3927 simple memory test is run that determines the size of the SDRAM
3930 When there is more than one SDRAM bank, and the banks are of
3931 different size, the largest is mapped first. For equal size, the first
3932 bank (CS2#) is mapped first. The first mapping is always for address
3933 0x00000000, with any additional banks following immediately to create
3934 contiguous memory starting from 0.
3936 Then, the monitor installs itself at the upper end of the SDRAM area
3937 and allocates memory for use by malloc() and for the global Board
3938 Info data; also, the exception vector code is copied to the low RAM
3939 pages, and the final stack is set up.
3941 Only after this relocation will you have a "normal" C environment;
3942 until that you are restricted in several ways, mostly because you are
3943 running from ROM, and because the code will have to be relocated to a
3947 U-Boot Porting Guide:
3948 ----------------------
3950 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3954 int main (int argc, char *argv[])
3956 sighandler_t no_more_time;
3958 signal (SIGALRM, no_more_time);
3959 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3961 if (available_money > available_manpower) {
3962 pay consultant to port U-Boot;
3966 Download latest U-Boot source;
3968 Subscribe to u-boot mailing list;
3971 email ("Hi, I am new to U-Boot, how do I get started?");
3975 Read the README file in the top level directory;
3976 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3977 Read the source, Luke;
3980 if (available_money > toLocalCurrency ($2500)) {
3983 Add a lot of aggravation and time;
3986 Create your own board support subdirectory;
3988 Create your own board config file;
3992 Add / modify source code;
3996 email ("Hi, I am having problems...");
3998 Send patch file to Wolfgang;
4003 void no_more_time (int sig)
4012 All contributions to U-Boot should conform to the Linux kernel
4013 coding style; see the file "Documentation/CodingStyle" and the script
4014 "scripts/Lindent" in your Linux kernel source directory. In sources
4015 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4016 spaces before parameters to function calls) is actually used.
4018 Source files originating from a different project (for example the
4019 MTD subsystem) are generally exempt from these guidelines and are not
4020 reformated to ease subsequent migration to newer versions of those
4023 Please note that U-Boot is implemented in C (and to some small parts in
4024 Assembler); no C++ is used, so please do not use C++ style comments (//)
4027 Please also stick to the following formatting rules:
4028 - remove any trailing white space
4029 - use TAB characters for indentation, not spaces
4030 - make sure NOT to use DOS '\r\n' line feeds
4031 - do not add more than 2 empty lines to source files
4032 - do not add trailing empty lines to source files
4034 Submissions which do not conform to the standards may be returned
4035 with a request to reformat the changes.
4041 Since the number of patches for U-Boot is growing, we need to
4042 establish some rules. Submissions which do not conform to these rules
4043 may be rejected, even when they contain important and valuable stuff.
4045 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4047 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4048 see http://lists.denx.de/mailman/listinfo/u-boot
4050 When you send a patch, please include the following information with
4053 * For bug fixes: a description of the bug and how your patch fixes
4054 this bug. Please try to include a way of demonstrating that the
4055 patch actually fixes something.
4057 * For new features: a description of the feature and your
4060 * A CHANGELOG entry as plaintext (separate from the patch)
4062 * For major contributions, your entry to the CREDITS file
4064 * When you add support for a new board, don't forget to add this
4065 board to the MAKEALL script, too.
4067 * If your patch adds new configuration options, don't forget to
4068 document these in the README file.
4070 * The patch itself. If you are using git (which is *strongly*
4071 recommended) you can easily generate the patch using the
4072 "git-format-patch". If you then use "git-send-email" to send it to
4073 the U-Boot mailing list, you will avoid most of the common problems
4074 with some other mail clients.
4076 If you cannot use git, use "diff -purN OLD NEW". If your version of
4077 diff does not support these options, then get the latest version of
4080 The current directory when running this command shall be the parent
4081 directory of the U-Boot source tree (i. e. please make sure that
4082 your patch includes sufficient directory information for the
4085 We prefer patches as plain text. MIME attachments are discouraged,
4086 and compressed attachments must not be used.
4088 * If one logical set of modifications affects or creates several
4089 files, all these changes shall be submitted in a SINGLE patch file.
4091 * Changesets that contain different, unrelated modifications shall be
4092 submitted as SEPARATE patches, one patch per changeset.
4097 * Before sending the patch, run the MAKEALL script on your patched
4098 source tree and make sure that no errors or warnings are reported
4099 for any of the boards.
4101 * Keep your modifications to the necessary minimum: A patch
4102 containing several unrelated changes or arbitrary reformats will be
4103 returned with a request to re-formatting / split it.
4105 * If you modify existing code, make sure that your new code does not
4106 add to the memory footprint of the code ;-) Small is beautiful!
4107 When adding new features, these should compile conditionally only
4108 (using #ifdef), and the resulting code with the new feature
4109 disabled must not need more memory than the old code without your
4112 * Remember that there is a size limit of 100 kB per message on the
4113 u-boot mailing list. Bigger patches will be moderated. If they are
4114 reasonable and not too big, they will be acknowledged. But patches
4115 bigger than the size limit should be avoided.
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