2 # (C) Copyright 2000 - 2008
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - blackfin Files specific to Analog Devices Blackfin CPUs
155 - i386 Files specific to i386 CPUs
156 - ixp Files specific to Intel XScale IXP CPUs
157 - leon2 Files specific to Gaisler LEON2 SPARC CPU
158 - leon3 Files specific to Gaisler LEON3 SPARC CPU
159 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 - mips Files specific to MIPS CPUs
165 - mpc5xx Files specific to Freescale MPC5xx CPUs
166 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
167 - mpc8xx Files specific to Freescale MPC8xx CPUs
168 - mpc8220 Files specific to Freescale MPC8220 CPUs
169 - mpc824x Files specific to Freescale MPC824x CPUs
170 - mpc8260 Files specific to Freescale MPC8260 CPUs
171 - mpc85xx Files specific to Freescale MPC85xx CPUs
172 - nios Files specific to Altera NIOS CPUs
173 - nios2 Files specific to Altera Nios-II CPUs
174 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
175 - pxa Files specific to Intel XScale PXA CPUs
176 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
177 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
178 - disk Code for disk drive partition handling
179 - doc Documentation (don't expect too much)
180 - drivers Commonly used device drivers
181 - dtt Digital Thermometer and Thermostat drivers
182 - examples Example code for standalone applications, etc.
183 - include Header Files
184 - lib_arm Files generic to ARM architecture
185 - lib_avr32 Files generic to AVR32 architecture
186 - lib_blackfin Files generic to Blackfin architecture
187 - lib_generic Files generic to all architectures
188 - lib_i386 Files generic to i386 architecture
189 - lib_m68k Files generic to m68k architecture
190 - lib_mips Files generic to MIPS architecture
191 - lib_nios Files generic to NIOS architecture
192 - lib_ppc Files generic to PowerPC architecture
193 - lib_sparc Files generic to SPARC architecture
194 - libfdt Library files to support flattened device trees
195 - net Networking code
196 - post Power On Self Test
197 - rtc Real Time Clock drivers
198 - tools Tools to build S-Record or U-Boot images, etc.
200 Software Configuration:
201 =======================
203 Configuration is usually done using C preprocessor defines; the
204 rationale behind that is to avoid dead code whenever possible.
206 There are two classes of configuration variables:
208 * Configuration _OPTIONS_:
209 These are selectable by the user and have names beginning with
212 * Configuration _SETTINGS_:
213 These depend on the hardware etc. and should not be meddled with if
214 you don't know what you're doing; they have names beginning with
217 Later we will add a configuration tool - probably similar to or even
218 identical to what's used for the Linux kernel. Right now, we have to
219 do the configuration by hand, which means creating some symbolic
220 links and editing some configuration files. We use the TQM8xxL boards
224 Selection of Processor Architecture and Board Type:
225 ---------------------------------------------------
227 For all supported boards there are ready-to-use default
228 configurations available; just type "make <board_name>_config".
230 Example: For a TQM823L module type:
235 For the Cogent platform, you need to specify the CPU type as well;
236 e.g. "make cogent_mpc8xx_config". And also configure the cogent
237 directory according to the instructions in cogent/README.
240 Configuration Options:
241 ----------------------
243 Configuration depends on the combination of board and CPU type; all
244 such information is kept in a configuration file
245 "include/configs/<board_name>.h".
247 Example: For a TQM823L module, all configuration settings are in
248 "include/configs/TQM823L.h".
251 Many of the options are named exactly as the corresponding Linux
252 kernel configuration options. The intention is to make it easier to
253 build a config tool - later.
256 The following options need to be configured:
258 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
260 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
262 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
263 Define exactly one, e.g. CONFIG_ATSTK1002
265 - CPU Module Type: (if CONFIG_COGENT is defined)
266 Define exactly one of
268 --- FIXME --- not tested yet:
269 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
270 CONFIG_CMA287_23, CONFIG_CMA287_50
272 - Motherboard Type: (if CONFIG_COGENT is defined)
273 Define exactly one of
274 CONFIG_CMA101, CONFIG_CMA102
276 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
277 Define one or more of
280 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
281 Define one or more of
282 CONFIG_LCD_HEARTBEAT - update a character position on
283 the LCD display every second with
286 - Board flavour: (if CONFIG_MPC8260ADS is defined)
289 CONFIG_SYS_8260ADS - original MPC8260ADS
290 CONFIG_SYS_8266ADS - MPC8266ADS
291 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
292 CONFIG_SYS_8272ADS - MPC8272ADS
294 - MPC824X Family Member (if CONFIG_MPC824X is defined)
295 Define exactly one of
296 CONFIG_MPC8240, CONFIG_MPC8245
298 - 8xx CPU Options: (if using an MPC8xx CPU)
299 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
300 get_gclk_freq() cannot work
301 e.g. if there is no 32KHz
302 reference PIT/RTC clock
303 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
306 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
307 CONFIG_SYS_8xx_CPUCLK_MIN
308 CONFIG_SYS_8xx_CPUCLK_MAX
309 CONFIG_8xx_CPUCLK_DEFAULT
310 See doc/README.MPC866
312 CONFIG_SYS_MEASURE_CPUCLK
314 Define this to measure the actual CPU clock instead
315 of relying on the correctness of the configured
316 values. Mostly useful for board bringup to make sure
317 the PLL is locked at the intended frequency. Note
318 that this requires a (stable) reference clock (32 kHz
319 RTC clock or CONFIG_SYS_8XX_XIN)
321 - Intel Monahans options:
322 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
324 Defines the Monahans run mode to oscillator
325 ratio. Valid values are 8, 16, 24, 31. The core
326 frequency is this value multiplied by 13 MHz.
328 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
330 Defines the Monahans turbo mode to oscillator
331 ratio. Valid values are 1 (default if undefined) and
332 2. The core frequency as calculated above is multiplied
335 - Linux Kernel Interface:
338 U-Boot stores all clock information in Hz
339 internally. For binary compatibility with older Linux
340 kernels (which expect the clocks passed in the
341 bd_info data to be in MHz) the environment variable
342 "clocks_in_mhz" can be defined so that U-Boot
343 converts clock data to MHZ before passing it to the
345 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
346 "clocks_in_mhz=1" is automatically included in the
349 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
351 When transferring memsize parameter to linux, some versions
352 expect it to be in bytes, others in MB.
353 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
357 New kernel versions are expecting firmware settings to be
358 passed using flattened device trees (based on open firmware
362 * New libfdt-based support
363 * Adds the "fdt" command
364 * The bootm command automatically updates the fdt
366 OF_CPU - The proper name of the cpus node.
367 OF_SOC - The proper name of the soc node.
368 OF_TBCLK - The timebase frequency.
369 OF_STDOUT_PATH - The path to the console device
371 boards with QUICC Engines require OF_QE to set UCC MAC
374 CONFIG_OF_BOARD_SETUP
376 Board code has addition modification that it wants to make
377 to the flat device tree before handing it off to the kernel
381 This define fills in the correct boot CPU in the boot
382 param header, the default value is zero if undefined.
384 - vxWorks boot parameters:
386 bootvx constructs a valid bootline using the following
387 environments variables: bootfile, ipaddr, serverip, hostname.
388 It loads the vxWorks image pointed bootfile.
390 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
391 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
392 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
393 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
395 CONFIG_SYS_VXWORKS_ADD_PARAMS
397 Add it at the end of the bootline. E.g "u=username pw=secret"
399 Note: If a "bootargs" environment is defined, it will overwride
400 the defaults discussed just above.
405 Define this if you want support for Amba PrimeCell PL010 UARTs.
409 Define this if you want support for Amba PrimeCell PL011 UARTs.
413 If you have Amba PrimeCell PL011 UARTs, set this variable to
414 the clock speed of the UARTs.
418 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
419 define this to a list of base addresses for each (supported)
420 port. See e.g. include/configs/versatile.h
424 Depending on board, define exactly one serial port
425 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
426 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
427 console by defining CONFIG_8xx_CONS_NONE
429 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
430 port routines must be defined elsewhere
431 (i.e. serial_init(), serial_getc(), ...)
434 Enables console device for a color framebuffer. Needs following
435 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
436 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
438 VIDEO_HW_RECTFILL graphic chip supports
441 VIDEO_HW_BITBLT graphic chip supports
442 bit-blit (cf. smiLynxEM)
443 VIDEO_VISIBLE_COLS visible pixel columns
445 VIDEO_VISIBLE_ROWS visible pixel rows
446 VIDEO_PIXEL_SIZE bytes per pixel
447 VIDEO_DATA_FORMAT graphic data format
448 (0-5, cf. cfb_console.c)
449 VIDEO_FB_ADRS framebuffer address
450 VIDEO_KBD_INIT_FCT keyboard int fct
451 (i.e. i8042_kbd_init())
452 VIDEO_TSTC_FCT test char fct
454 VIDEO_GETC_FCT get char fct
456 CONFIG_CONSOLE_CURSOR cursor drawing on/off
457 (requires blink timer
459 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
460 CONFIG_CONSOLE_TIME display time/date info in
462 (requires CONFIG_CMD_DATE)
463 CONFIG_VIDEO_LOGO display Linux logo in
465 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
466 linux_logo.h for logo.
467 Requires CONFIG_VIDEO_LOGO
468 CONFIG_CONSOLE_EXTRA_INFO
469 additional board info beside
472 When CONFIG_CFB_CONSOLE is defined, video console is
473 default i/o. Serial console can be forced with
474 environment 'console=serial'.
476 When CONFIG_SILENT_CONSOLE is defined, all console
477 messages (by U-Boot and Linux!) can be silenced with
478 the "silent" environment variable. See
479 doc/README.silent for more information.
482 CONFIG_BAUDRATE - in bps
483 Select one of the baudrates listed in
484 CONFIG_SYS_BAUDRATE_TABLE, see below.
485 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
487 - Interrupt driven serial port input:
488 CONFIG_SERIAL_SOFTWARE_FIFO
491 Use an interrupt handler for receiving data on the
492 serial port. It also enables using hardware handshake
493 (RTS/CTS) and UART's built-in FIFO. Set the number of
494 bytes the interrupt driven input buffer should have.
496 Leave undefined to disable this feature, including
497 disable the buffer and hardware handshake.
499 - Console UART Number:
503 If defined internal UART1 (and not UART0) is used
504 as default U-Boot console.
506 - Boot Delay: CONFIG_BOOTDELAY - in seconds
507 Delay before automatically booting the default image;
508 set to -1 to disable autoboot.
510 See doc/README.autoboot for these options that
511 work with CONFIG_BOOTDELAY. None are required.
512 CONFIG_BOOT_RETRY_TIME
513 CONFIG_BOOT_RETRY_MIN
514 CONFIG_AUTOBOOT_KEYED
515 CONFIG_AUTOBOOT_PROMPT
516 CONFIG_AUTOBOOT_DELAY_STR
517 CONFIG_AUTOBOOT_STOP_STR
518 CONFIG_AUTOBOOT_DELAY_STR2
519 CONFIG_AUTOBOOT_STOP_STR2
520 CONFIG_ZERO_BOOTDELAY_CHECK
521 CONFIG_RESET_TO_RETRY
525 Only needed when CONFIG_BOOTDELAY is enabled;
526 define a command string that is automatically executed
527 when no character is read on the console interface
528 within "Boot Delay" after reset.
531 This can be used to pass arguments to the bootm
532 command. The value of CONFIG_BOOTARGS goes into the
533 environment value "bootargs".
535 CONFIG_RAMBOOT and CONFIG_NFSBOOT
536 The value of these goes into the environment as
537 "ramboot" and "nfsboot" respectively, and can be used
538 as a convenience, when switching between booting from
544 When this option is #defined, the existence of the
545 environment variable "preboot" will be checked
546 immediately before starting the CONFIG_BOOTDELAY
547 countdown and/or running the auto-boot command resp.
548 entering interactive mode.
550 This feature is especially useful when "preboot" is
551 automatically generated or modified. For an example
552 see the LWMON board specific code: here "preboot" is
553 modified when the user holds down a certain
554 combination of keys on the (special) keyboard when
557 - Serial Download Echo Mode:
559 If defined to 1, all characters received during a
560 serial download (using the "loads" command) are
561 echoed back. This might be needed by some terminal
562 emulations (like "cu"), but may as well just take
563 time on others. This setting #define's the initial
564 value of the "loads_echo" environment variable.
566 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
568 Select one of the baudrates listed in
569 CONFIG_SYS_BAUDRATE_TABLE, see below.
572 Monitor commands can be included or excluded
573 from the build by using the #include files
574 "config_cmd_all.h" and #undef'ing unwanted
575 commands, or using "config_cmd_default.h"
576 and augmenting with additional #define's
579 The default command configuration includes all commands
580 except those marked below with a "*".
582 CONFIG_CMD_ASKENV * ask for env variable
583 CONFIG_CMD_AUTOSCRIPT Autoscript Support
584 CONFIG_CMD_BDI bdinfo
585 CONFIG_CMD_BEDBUG * Include BedBug Debugger
586 CONFIG_CMD_BMP * BMP support
587 CONFIG_CMD_BSP * Board specific commands
588 CONFIG_CMD_BOOTD bootd
589 CONFIG_CMD_CACHE * icache, dcache
590 CONFIG_CMD_CONSOLE coninfo
591 CONFIG_CMD_DATE * support for RTC, date/time...
592 CONFIG_CMD_DHCP * DHCP support
593 CONFIG_CMD_DIAG * Diagnostics
594 CONFIG_CMD_DOC * Disk-On-Chip Support
595 CONFIG_CMD_DTT * Digital Therm and Thermostat
596 CONFIG_CMD_ECHO echo arguments
597 CONFIG_CMD_EEPROM * EEPROM read/write support
598 CONFIG_CMD_ELF * bootelf, bootvx
599 CONFIG_CMD_ENV saveenv
600 CONFIG_CMD_FDC * Floppy Disk Support
601 CONFIG_CMD_FAT * FAT partition support
602 CONFIG_CMD_FDOS * Dos diskette Support
603 CONFIG_CMD_FLASH flinfo, erase, protect
604 CONFIG_CMD_FPGA FPGA device initialization support
605 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
606 CONFIG_CMD_I2C * I2C serial bus support
607 CONFIG_CMD_IDE * IDE harddisk support
608 CONFIG_CMD_IMI iminfo
609 CONFIG_CMD_IMLS List all found images
610 CONFIG_CMD_IMMAP * IMMR dump support
611 CONFIG_CMD_IRQ * irqinfo
612 CONFIG_CMD_ITEST Integer/string test of 2 values
613 CONFIG_CMD_JFFS2 * JFFS2 Support
614 CONFIG_CMD_KGDB * kgdb
615 CONFIG_CMD_LOADB loadb
616 CONFIG_CMD_LOADS loads
617 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
619 CONFIG_CMD_MISC Misc functions like sleep etc
620 CONFIG_CMD_MMC * MMC memory mapped support
621 CONFIG_CMD_MII * MII utility commands
622 CONFIG_CMD_NAND * NAND support
623 CONFIG_CMD_NET bootp, tftpboot, rarpboot
624 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
625 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
626 CONFIG_CMD_PCI * pciinfo
627 CONFIG_CMD_PCMCIA * PCMCIA support
628 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
630 CONFIG_CMD_PORTIO * Port I/O
631 CONFIG_CMD_REGINFO * Register dump
632 CONFIG_CMD_RUN run command in env variable
633 CONFIG_CMD_SAVES * save S record dump
634 CONFIG_CMD_SCSI * SCSI Support
635 CONFIG_CMD_SDRAM * print SDRAM configuration information
636 (requires CONFIG_CMD_I2C)
637 CONFIG_CMD_SETGETDCR Support for DCR Register access
639 CONFIG_CMD_SPI * SPI serial bus support
640 CONFIG_CMD_USB * USB support
641 CONFIG_CMD_VFD * VFD support (TRAB)
642 CONFIG_CMD_CDP * Cisco Discover Protocol support
643 CONFIG_CMD_FSL * Microblaze FSL support
646 EXAMPLE: If you want all functions except of network
647 support you can write:
649 #include "config_cmd_all.h"
650 #undef CONFIG_CMD_NET
653 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
655 Note: Don't enable the "icache" and "dcache" commands
656 (configuration option CONFIG_CMD_CACHE) unless you know
657 what you (and your U-Boot users) are doing. Data
658 cache cannot be enabled on systems like the 8xx or
659 8260 (where accesses to the IMMR region must be
660 uncached), and it cannot be disabled on all other
661 systems where we (mis-) use the data cache to hold an
662 initial stack and some data.
665 XXX - this list needs to get updated!
669 If this variable is defined, it enables watchdog
670 support. There must be support in the platform specific
671 code for a watchdog. For the 8xx and 8260 CPUs, the
672 SIU Watchdog feature is enabled in the SYPCR
676 CONFIG_VERSION_VARIABLE
677 If this variable is defined, an environment variable
678 named "ver" is created by U-Boot showing the U-Boot
679 version as printed by the "version" command.
680 This variable is readonly.
684 When CONFIG_CMD_DATE is selected, the type of the RTC
685 has to be selected, too. Define exactly one of the
688 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
689 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
690 CONFIG_RTC_MC13783 - use MC13783 RTC
691 CONFIG_RTC_MC146818 - use MC146818 RTC
692 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
693 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
694 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
695 CONFIG_RTC_DS164x - use Dallas DS164x RTC
696 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
697 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
698 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
700 Note that if the RTC uses I2C, then the I2C interface
701 must also be configured. See I2C Support, below.
704 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
705 CONFIG_PCA953X_INFO - enable pca953x info command
707 Note that if the GPIO device uses I2C, then the I2C interface
708 must also be configured. See I2C Support, below.
712 When CONFIG_TIMESTAMP is selected, the timestamp
713 (date and time) of an image is printed by image
714 commands like bootm or iminfo. This option is
715 automatically enabled when you select CONFIG_CMD_DATE .
718 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
719 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
721 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
722 CONFIG_CMD_SCSI) you must configure support for at
723 least one partition type as well.
726 CONFIG_IDE_RESET_ROUTINE - this is defined in several
727 board configurations files but used nowhere!
729 CONFIG_IDE_RESET - is this is defined, IDE Reset will
730 be performed by calling the function
731 ide_set_reset(int reset)
732 which has to be defined in a board specific file
737 Set this to enable ATAPI support.
742 Set this to enable support for disks larger than 137GB
743 Also look at CONFIG_SYS_64BIT_LBA ,CONFIG_SYS_64BIT_VSPRINTF and CONFIG_SYS_64BIT_STRTOUL
744 Whithout these , LBA48 support uses 32bit variables and will 'only'
745 support disks up to 2.1TB.
747 CONFIG_SYS_64BIT_LBA:
748 When enabled, makes the IDE subsystem use 64bit sector addresses.
752 At the moment only there is only support for the
753 SYM53C8XX SCSI controller; define
754 CONFIG_SCSI_SYM53C8XX to enable it.
756 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
757 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
758 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
759 maximum numbers of LUNs, SCSI ID's and target
761 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
763 - NETWORK Support (PCI):
765 Support for Intel 8254x gigabit chips.
767 CONFIG_E1000_FALLBACK_MAC
768 default MAC for empty EEPROM after production.
771 Support for Intel 82557/82559/82559ER chips.
772 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
773 write routine for first time initialisation.
776 Support for Digital 2114x chips.
777 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
778 modem chip initialisation (KS8761/QS6611).
781 Support for National dp83815 chips.
784 Support for National dp8382[01] gigabit chips.
786 - NETWORK Support (other):
788 CONFIG_DRIVER_LAN91C96
789 Support for SMSC's LAN91C96 chips.
792 Define this to hold the physical address
793 of the LAN91C96's I/O space
795 CONFIG_LAN91C96_USE_32_BIT
796 Define this to enable 32 bit addressing
798 CONFIG_DRIVER_SMC91111
799 Support for SMSC's LAN91C111 chip
802 Define this to hold the physical address
803 of the device (I/O space)
805 CONFIG_SMC_USE_32_BIT
806 Define this if data bus is 32 bits
808 CONFIG_SMC_USE_IOFUNCS
809 Define this to use i/o functions instead of macros
810 (some hardware wont work with macros)
812 CONFIG_DRIVER_SMC911X
813 Support for SMSC's LAN911x and LAN921x chips
815 CONFIG_DRIVER_SMC911X_BASE
816 Define this to hold the physical address
817 of the device (I/O space)
819 CONFIG_DRIVER_SMC911X_32_BIT
820 Define this if data bus is 32 bits
822 CONFIG_DRIVER_SMC911X_16_BIT
823 Define this if data bus is 16 bits. If your processor
824 automatically converts one 32 bit word to two 16 bit
825 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
828 At the moment only the UHCI host controller is
829 supported (PIP405, MIP405, MPC5200); define
830 CONFIG_USB_UHCI to enable it.
831 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
832 and define CONFIG_USB_STORAGE to enable the USB
835 Supported are USB Keyboards and USB Floppy drives
837 MPC5200 USB requires additional defines:
839 for 528 MHz Clock: 0x0001bbbb
841 for differential drivers: 0x00001000
842 for single ended drivers: 0x00005000
843 CONFIG_SYS_USB_EVENT_POLL
844 May be defined to allow interrupt polling
845 instead of using asynchronous interrupts
848 Define the below if you wish to use the USB console.
849 Once firmware is rebuilt from a serial console issue the
850 command "setenv stdin usbtty; setenv stdout usbtty" and
851 attach your USB cable. The Unix command "dmesg" should print
852 it has found a new device. The environment variable usbtty
853 can be set to gserial or cdc_acm to enable your device to
854 appear to a USB host as a Linux gserial device or a
855 Common Device Class Abstract Control Model serial device.
856 If you select usbtty = gserial you should be able to enumerate
858 # modprobe usbserial vendor=0xVendorID product=0xProductID
859 else if using cdc_acm, simply setting the environment
860 variable usbtty to be cdc_acm should suffice. The following
861 might be defined in YourBoardName.h
864 Define this to build a UDC device
867 Define this to have a tty type of device available to
868 talk to the UDC device
870 CONFIG_SYS_CONSOLE_IS_IN_ENV
871 Define this if you want stdin, stdout &/or stderr to
875 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
876 Derive USB clock from external clock "blah"
877 - CONFIG_SYS_USB_EXTC_CLK 0x02
879 CONFIG_SYS_USB_BRG_CLK 0xBLAH
880 Derive USB clock from brgclk
881 - CONFIG_SYS_USB_BRG_CLK 0x04
883 If you have a USB-IF assigned VendorID then you may wish to
884 define your own vendor specific values either in BoardName.h
885 or directly in usbd_vendor_info.h. If you don't define
886 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
887 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
888 should pretend to be a Linux device to it's target host.
890 CONFIG_USBD_MANUFACTURER
891 Define this string as the name of your company for
892 - CONFIG_USBD_MANUFACTURER "my company"
894 CONFIG_USBD_PRODUCT_NAME
895 Define this string as the name of your product
896 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
899 Define this as your assigned Vendor ID from the USB
900 Implementors Forum. This *must* be a genuine Vendor ID
901 to avoid polluting the USB namespace.
902 - CONFIG_USBD_VENDORID 0xFFFF
904 CONFIG_USBD_PRODUCTID
905 Define this as the unique Product ID
907 - CONFIG_USBD_PRODUCTID 0xFFFF
911 The MMC controller on the Intel PXA is supported. To
912 enable this define CONFIG_MMC. The MMC can be
913 accessed from the boot prompt by mapping the device
914 to physical memory similar to flash. Command line is
915 enabled with CONFIG_CMD_MMC. The MMC driver also works with
916 the FAT fs. This is enabled with CONFIG_CMD_FAT.
918 - Journaling Flash filesystem support:
919 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
920 CONFIG_JFFS2_NAND_DEV
921 Define these for a default partition on a NAND device
923 CONFIG_SYS_JFFS2_FIRST_SECTOR,
924 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
925 Define these for a default partition on a NOR device
927 CONFIG_SYS_JFFS_CUSTOM_PART
928 Define this to create an own partition. You have to provide a
929 function struct part_info* jffs2_part_info(int part_num)
931 If you define only one JFFS2 partition you may also want to
932 #define CONFIG_SYS_JFFS_SINGLE_PART 1
933 to disable the command chpart. This is the default when you
934 have not defined a custom partition
939 Define this to enable standard (PC-Style) keyboard
943 Standard PC keyboard driver with US (is default) and
944 GERMAN key layout (switch via environment 'keymap=de') support.
945 Export function i8042_kbd_init, i8042_tstc and i8042_getc
946 for cfb_console. Supports cursor blinking.
951 Define this to enable video support (for output to
956 Enable Chips & Technologies 69000 Video chip
958 CONFIG_VIDEO_SMI_LYNXEM
959 Enable Silicon Motion SMI 712/710/810 Video chip. The
960 video output is selected via environment 'videoout'
961 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
964 For the CT69000 and SMI_LYNXEM drivers, videomode is
965 selected via environment 'videomode'. Two different ways
967 - "videomode=num" 'num' is a standard LiLo mode numbers.
968 Following standard modes are supported (* is default):
970 Colors 640x480 800x600 1024x768 1152x864 1280x1024
971 -------------+---------------------------------------------
972 8 bits | 0x301* 0x303 0x305 0x161 0x307
973 15 bits | 0x310 0x313 0x316 0x162 0x319
974 16 bits | 0x311 0x314 0x317 0x163 0x31A
975 24 bits | 0x312 0x315 0x318 ? 0x31B
976 -------------+---------------------------------------------
977 (i.e. setenv videomode 317; saveenv; reset;)
979 - "videomode=bootargs" all the video parameters are parsed
980 from the bootargs. (See drivers/video/videomodes.c)
983 CONFIG_VIDEO_SED13806
984 Enable Epson SED13806 driver. This driver supports 8bpp
985 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
986 or CONFIG_VIDEO_SED13806_16BPP
991 Define this to enable a custom keyboard support.
992 This simply calls drv_keyboard_init() which must be
993 defined in your board-specific files.
994 The only board using this so far is RBC823.
996 - LCD Support: CONFIG_LCD
998 Define this to enable LCD support (for output to LCD
999 display); also select one of the supported displays
1000 by defining one of these:
1004 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1006 CONFIG_NEC_NL6448AC33:
1008 NEC NL6448AC33-18. Active, color, single scan.
1010 CONFIG_NEC_NL6448BC20
1012 NEC NL6448BC20-08. 6.5", 640x480.
1013 Active, color, single scan.
1015 CONFIG_NEC_NL6448BC33_54
1017 NEC NL6448BC33-54. 10.4", 640x480.
1018 Active, color, single scan.
1022 Sharp 320x240. Active, color, single scan.
1023 It isn't 16x9, and I am not sure what it is.
1025 CONFIG_SHARP_LQ64D341
1027 Sharp LQ64D341 display, 640x480.
1028 Active, color, single scan.
1032 HLD1045 display, 640x480.
1033 Active, color, single scan.
1037 Optrex CBL50840-2 NF-FW 99 22 M5
1039 Hitachi LMG6912RPFC-00T
1043 320x240. Black & white.
1045 Normally display is black on white background; define
1046 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1048 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1050 If this option is set, the environment is checked for
1051 a variable "splashimage". If found, the usual display
1052 of logo, copyright and system information on the LCD
1053 is suppressed and the BMP image at the address
1054 specified in "splashimage" is loaded instead. The
1055 console is redirected to the "nulldev", too. This
1056 allows for a "silent" boot where a splash screen is
1057 loaded very quickly after power-on.
1059 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1061 If this option is set, additionally to standard BMP
1062 images, gzipped BMP images can be displayed via the
1063 splashscreen support or the bmp command.
1065 - Compression support:
1068 If this option is set, support for bzip2 compressed
1069 images is included. If not, only uncompressed and gzip
1070 compressed images are supported.
1072 NOTE: the bzip2 algorithm requires a lot of RAM, so
1073 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1078 If this option is set, support for lzma compressed
1081 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1082 requires an amount of dynamic memory that is given by the
1085 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1087 Where lc and lp stand for, respectively, Literal context bits
1088 and Literal pos bits.
1090 This value is upper-bounded by 14MB in the worst case. Anyway,
1091 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1092 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1093 a very small buffer.
1095 Use the lzmainfo tool to determinate the lc and lp values and
1096 then calculate the amount of needed dynamic memory (ensuring
1097 the appropriate CONFIG_SYS_MALLOC_LEN value).
1102 The address of PHY on MII bus.
1104 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1106 The clock frequency of the MII bus
1110 If this option is set, support for speed/duplex
1111 detection of gigabit PHY is included.
1113 CONFIG_PHY_RESET_DELAY
1115 Some PHY like Intel LXT971A need extra delay after
1116 reset before any MII register access is possible.
1117 For such PHY, set this option to the usec delay
1118 required. (minimum 300usec for LXT971A)
1120 CONFIG_PHY_CMD_DELAY (ppc4xx)
1122 Some PHY like Intel LXT971A need extra delay after
1123 command issued before MII status register can be read
1133 Define a default value for Ethernet address to use
1134 for the respective Ethernet interface, in case this
1135 is not determined automatically.
1140 Define a default value for the IP address to use for
1141 the default Ethernet interface, in case this is not
1142 determined through e.g. bootp.
1144 - Server IP address:
1147 Defines a default value for the IP address of a TFTP
1148 server to contact when using the "tftboot" command.
1150 - Multicast TFTP Mode:
1153 Defines whether you want to support multicast TFTP as per
1154 rfc-2090; for example to work with atftp. Lets lots of targets
1155 tftp down the same boot image concurrently. Note: the Ethernet
1156 driver in use must provide a function: mcast() to join/leave a
1159 CONFIG_BOOTP_RANDOM_DELAY
1160 - BOOTP Recovery Mode:
1161 CONFIG_BOOTP_RANDOM_DELAY
1163 If you have many targets in a network that try to
1164 boot using BOOTP, you may want to avoid that all
1165 systems send out BOOTP requests at precisely the same
1166 moment (which would happen for instance at recovery
1167 from a power failure, when all systems will try to
1168 boot, thus flooding the BOOTP server. Defining
1169 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1170 inserted before sending out BOOTP requests. The
1171 following delays are inserted then:
1173 1st BOOTP request: delay 0 ... 1 sec
1174 2nd BOOTP request: delay 0 ... 2 sec
1175 3rd BOOTP request: delay 0 ... 4 sec
1177 BOOTP requests: delay 0 ... 8 sec
1179 - DHCP Advanced Options:
1180 You can fine tune the DHCP functionality by defining
1181 CONFIG_BOOTP_* symbols:
1183 CONFIG_BOOTP_SUBNETMASK
1184 CONFIG_BOOTP_GATEWAY
1185 CONFIG_BOOTP_HOSTNAME
1186 CONFIG_BOOTP_NISDOMAIN
1187 CONFIG_BOOTP_BOOTPATH
1188 CONFIG_BOOTP_BOOTFILESIZE
1191 CONFIG_BOOTP_SEND_HOSTNAME
1192 CONFIG_BOOTP_NTPSERVER
1193 CONFIG_BOOTP_TIMEOFFSET
1194 CONFIG_BOOTP_VENDOREX
1196 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1197 environment variable, not the BOOTP server.
1199 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1200 serverip from a DHCP server, it is possible that more
1201 than one DNS serverip is offered to the client.
1202 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1203 serverip will be stored in the additional environment
1204 variable "dnsip2". The first DNS serverip is always
1205 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1208 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1209 to do a dynamic update of a DNS server. To do this, they
1210 need the hostname of the DHCP requester.
1211 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1212 of the "hostname" environment variable is passed as
1213 option 12 to the DHCP server.
1215 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1217 A 32bit value in microseconds for a delay between
1218 receiving a "DHCP Offer" and sending the "DHCP Request".
1219 This fixes a problem with certain DHCP servers that don't
1220 respond 100% of the time to a "DHCP request". E.g. On an
1221 AT91RM9200 processor running at 180MHz, this delay needed
1222 to be *at least* 15,000 usec before a Windows Server 2003
1223 DHCP server would reply 100% of the time. I recommend at
1224 least 50,000 usec to be safe. The alternative is to hope
1225 that one of the retries will be successful but note that
1226 the DHCP timeout and retry process takes a longer than
1230 CONFIG_CDP_DEVICE_ID
1232 The device id used in CDP trigger frames.
1234 CONFIG_CDP_DEVICE_ID_PREFIX
1236 A two character string which is prefixed to the MAC address
1241 A printf format string which contains the ascii name of
1242 the port. Normally is set to "eth%d" which sets
1243 eth0 for the first Ethernet, eth1 for the second etc.
1245 CONFIG_CDP_CAPABILITIES
1247 A 32bit integer which indicates the device capabilities;
1248 0x00000010 for a normal host which does not forwards.
1252 An ascii string containing the version of the software.
1256 An ascii string containing the name of the platform.
1260 A 32bit integer sent on the trigger.
1262 CONFIG_CDP_POWER_CONSUMPTION
1264 A 16bit integer containing the power consumption of the
1265 device in .1 of milliwatts.
1267 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1269 A byte containing the id of the VLAN.
1271 - Status LED: CONFIG_STATUS_LED
1273 Several configurations allow to display the current
1274 status using a LED. For instance, the LED will blink
1275 fast while running U-Boot code, stop blinking as
1276 soon as a reply to a BOOTP request was received, and
1277 start blinking slow once the Linux kernel is running
1278 (supported by a status LED driver in the Linux
1279 kernel). Defining CONFIG_STATUS_LED enables this
1282 - CAN Support: CONFIG_CAN_DRIVER
1284 Defining CONFIG_CAN_DRIVER enables CAN driver support
1285 on those systems that support this (optional)
1286 feature, like the TQM8xxL modules.
1288 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1290 These enable I2C serial bus commands. Defining either of
1291 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1292 include the appropriate I2C driver for the selected CPU.
1294 This will allow you to use i2c commands at the u-boot
1295 command line (as long as you set CONFIG_CMD_I2C in
1296 CONFIG_COMMANDS) and communicate with i2c based realtime
1297 clock chips. See common/cmd_i2c.c for a description of the
1298 command line interface.
1300 CONFIG_I2C_CMD_TREE is a recommended option that places
1301 all I2C commands under a single 'i2c' root command. The
1302 older 'imm', 'imd', 'iprobe' etc. commands are considered
1303 deprecated and may disappear in the future.
1305 CONFIG_HARD_I2C selects a hardware I2C controller.
1307 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1308 bit-banging) driver instead of CPM or similar hardware
1311 There are several other quantities that must also be
1312 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1314 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1315 to be the frequency (in Hz) at which you wish your i2c bus
1316 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1317 the CPU's i2c node address).
1319 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1320 sets the CPU up as a master node and so its address should
1321 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1322 p.16-473). So, set CONFIG_SYS_I2C_SLAVE to 0.
1324 That's all that's required for CONFIG_HARD_I2C.
1326 If you use the software i2c interface (CONFIG_SOFT_I2C)
1327 then the following macros need to be defined (examples are
1328 from include/configs/lwmon.h):
1332 (Optional). Any commands necessary to enable the I2C
1333 controller or configure ports.
1335 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1339 (Only for MPC8260 CPU). The I/O port to use (the code
1340 assumes both bits are on the same port). Valid values
1341 are 0..3 for ports A..D.
1345 The code necessary to make the I2C data line active
1346 (driven). If the data line is open collector, this
1349 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1353 The code necessary to make the I2C data line tri-stated
1354 (inactive). If the data line is open collector, this
1357 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1361 Code that returns TRUE if the I2C data line is high,
1364 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1368 If <bit> is TRUE, sets the I2C data line high. If it
1369 is FALSE, it clears it (low).
1371 eg: #define I2C_SDA(bit) \
1372 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1373 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1377 If <bit> is TRUE, sets the I2C clock line high. If it
1378 is FALSE, it clears it (low).
1380 eg: #define I2C_SCL(bit) \
1381 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1382 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1386 This delay is invoked four times per clock cycle so this
1387 controls the rate of data transfer. The data rate thus
1388 is 1 / (I2C_DELAY * 4). Often defined to be something
1391 #define I2C_DELAY udelay(2)
1393 CONFIG_SYS_I2C_INIT_BOARD
1395 When a board is reset during an i2c bus transfer
1396 chips might think that the current transfer is still
1397 in progress. On some boards it is possible to access
1398 the i2c SCLK line directly, either by using the
1399 processor pin as a GPIO or by having a second pin
1400 connected to the bus. If this option is defined a
1401 custom i2c_init_board() routine in boards/xxx/board.c
1402 is run early in the boot sequence.
1404 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1406 This option enables configuration of bi_iic_fast[] flags
1407 in u-boot bd_info structure based on u-boot environment
1408 variable "i2cfast". (see also i2cfast)
1410 CONFIG_I2C_MULTI_BUS
1412 This option allows the use of multiple I2C buses, each of which
1413 must have a controller. At any point in time, only one bus is
1414 active. To switch to a different bus, use the 'i2c dev' command.
1415 Note that bus numbering is zero-based.
1417 CONFIG_SYS_I2C_NOPROBES
1419 This option specifies a list of I2C devices that will be skipped
1420 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1421 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1422 pairs. Otherwise, specify a 1D array of device addresses
1425 #undef CONFIG_I2C_MULTI_BUS
1426 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1428 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1430 #define CONFIG_I2C_MULTI_BUS
1431 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1433 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1435 CONFIG_SYS_SPD_BUS_NUM
1437 If defined, then this indicates the I2C bus number for DDR SPD.
1438 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1440 CONFIG_SYS_RTC_BUS_NUM
1442 If defined, then this indicates the I2C bus number for the RTC.
1443 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1445 CONFIG_SYS_DTT_BUS_NUM
1447 If defined, then this indicates the I2C bus number for the DTT.
1448 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1450 CONFIG_SYS_I2C_DTT_ADDR:
1452 If defined, specifies the I2C address of the DTT device.
1453 If not defined, then U-Boot uses predefined value for
1454 specified DTT device.
1458 Define this option if you want to use Freescale's I2C driver in
1459 drivers/i2c/fsl_i2c.c.
1463 Define this option if you have I2C devices reached over 1 .. n
1464 I2C Muxes like the pca9544a. This option addes a new I2C
1465 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1466 new I2C Bus to the existing I2C Busses. If you select the
1467 new Bus with "i2c dev", u-bbot sends first the commandos for
1468 the muxes to activate this new "bus".
1470 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1474 Adding a new I2C Bus reached over 2 pca9544a muxes
1475 The First mux with address 70 and channel 6
1476 The Second mux with address 71 and channel 4
1478 => i2c bus pca9544a:70:6:pca9544a:71:4
1480 Use the "i2c bus" command without parameter, to get a list
1481 of I2C Busses with muxes:
1484 Busses reached over muxes:
1486 reached over Mux(es):
1489 reached over Mux(es):
1494 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1495 u-boot sends First the Commando to the mux@70 to enable
1496 channel 6, and then the Commando to the mux@71 to enable
1499 After that, you can use the "normal" i2c commands as
1500 usual, to communicate with your I2C devices behind
1503 This option is actually implemented for the bitbanging
1504 algorithm in common/soft_i2c.c and for the Hardware I2C
1505 Bus on the MPC8260. But it should be not so difficult
1506 to add this option to other architectures.
1509 - SPI Support: CONFIG_SPI
1511 Enables SPI driver (so far only tested with
1512 SPI EEPROM, also an instance works with Crystal A/D and
1513 D/As on the SACSng board)
1517 Enables extended (16-bit) SPI EEPROM addressing.
1518 (symmetrical to CONFIG_I2C_X)
1522 Enables a software (bit-bang) SPI driver rather than
1523 using hardware support. This is a general purpose
1524 driver that only requires three general I/O port pins
1525 (two outputs, one input) to function. If this is
1526 defined, the board configuration must define several
1527 SPI configuration items (port pins to use, etc). For
1528 an example, see include/configs/sacsng.h.
1532 Enables a hardware SPI driver for general-purpose reads
1533 and writes. As with CONFIG_SOFT_SPI, the board configuration
1534 must define a list of chip-select function pointers.
1535 Currently supported on some MPC8xxx processors. For an
1536 example, see include/configs/mpc8349emds.h.
1540 Enables the driver for the SPI controllers on i.MX and MXC
1541 SoCs. Currently only i.MX31 is supported.
1543 - FPGA Support: CONFIG_FPGA
1545 Enables FPGA subsystem.
1547 CONFIG_FPGA_<vendor>
1549 Enables support for specific chip vendors.
1552 CONFIG_FPGA_<family>
1554 Enables support for FPGA family.
1555 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1559 Specify the number of FPGA devices to support.
1561 CONFIG_SYS_FPGA_PROG_FEEDBACK
1563 Enable printing of hash marks during FPGA configuration.
1565 CONFIG_SYS_FPGA_CHECK_BUSY
1567 Enable checks on FPGA configuration interface busy
1568 status by the configuration function. This option
1569 will require a board or device specific function to
1574 If defined, a function that provides delays in the FPGA
1575 configuration driver.
1577 CONFIG_SYS_FPGA_CHECK_CTRLC
1578 Allow Control-C to interrupt FPGA configuration
1580 CONFIG_SYS_FPGA_CHECK_ERROR
1582 Check for configuration errors during FPGA bitfile
1583 loading. For example, abort during Virtex II
1584 configuration if the INIT_B line goes low (which
1585 indicated a CRC error).
1587 CONFIG_SYS_FPGA_WAIT_INIT
1589 Maximum time to wait for the INIT_B line to deassert
1590 after PROB_B has been deasserted during a Virtex II
1591 FPGA configuration sequence. The default time is 500
1594 CONFIG_SYS_FPGA_WAIT_BUSY
1596 Maximum time to wait for BUSY to deassert during
1597 Virtex II FPGA configuration. The default is 5 ms.
1599 CONFIG_SYS_FPGA_WAIT_CONFIG
1601 Time to wait after FPGA configuration. The default is
1604 - Configuration Management:
1607 If defined, this string will be added to the U-Boot
1608 version information (U_BOOT_VERSION)
1610 - Vendor Parameter Protection:
1612 U-Boot considers the values of the environment
1613 variables "serial#" (Board Serial Number) and
1614 "ethaddr" (Ethernet Address) to be parameters that
1615 are set once by the board vendor / manufacturer, and
1616 protects these variables from casual modification by
1617 the user. Once set, these variables are read-only,
1618 and write or delete attempts are rejected. You can
1619 change this behaviour:
1621 If CONFIG_ENV_OVERWRITE is #defined in your config
1622 file, the write protection for vendor parameters is
1623 completely disabled. Anybody can change or delete
1626 Alternatively, if you #define _both_ CONFIG_ETHADDR
1627 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1628 Ethernet address is installed in the environment,
1629 which can be changed exactly ONCE by the user. [The
1630 serial# is unaffected by this, i. e. it remains
1636 Define this variable to enable the reservation of
1637 "protected RAM", i. e. RAM which is not overwritten
1638 by U-Boot. Define CONFIG_PRAM to hold the number of
1639 kB you want to reserve for pRAM. You can overwrite
1640 this default value by defining an environment
1641 variable "pram" to the number of kB you want to
1642 reserve. Note that the board info structure will
1643 still show the full amount of RAM. If pRAM is
1644 reserved, a new environment variable "mem" will
1645 automatically be defined to hold the amount of
1646 remaining RAM in a form that can be passed as boot
1647 argument to Linux, for instance like that:
1649 setenv bootargs ... mem=\${mem}
1652 This way you can tell Linux not to use this memory,
1653 either, which results in a memory region that will
1654 not be affected by reboots.
1656 *WARNING* If your board configuration uses automatic
1657 detection of the RAM size, you must make sure that
1658 this memory test is non-destructive. So far, the
1659 following board configurations are known to be
1662 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1663 HERMES, IP860, RPXlite, LWMON, LANTEC,
1664 PCU_E, FLAGADM, TQM8260
1669 Define this variable to stop the system in case of a
1670 fatal error, so that you have to reset it manually.
1671 This is probably NOT a good idea for an embedded
1672 system where you want the system to reboot
1673 automatically as fast as possible, but it may be
1674 useful during development since you can try to debug
1675 the conditions that lead to the situation.
1677 CONFIG_NET_RETRY_COUNT
1679 This variable defines the number of retries for
1680 network operations like ARP, RARP, TFTP, or BOOTP
1681 before giving up the operation. If not defined, a
1682 default value of 5 is used.
1686 Timeout waiting for an ARP reply in milliseconds.
1688 - Command Interpreter:
1689 CONFIG_AUTO_COMPLETE
1691 Enable auto completion of commands using TAB.
1693 Note that this feature has NOT been implemented yet
1694 for the "hush" shell.
1697 CONFIG_SYS_HUSH_PARSER
1699 Define this variable to enable the "hush" shell (from
1700 Busybox) as command line interpreter, thus enabling
1701 powerful command line syntax like
1702 if...then...else...fi conditionals or `&&' and '||'
1703 constructs ("shell scripts").
1705 If undefined, you get the old, much simpler behaviour
1706 with a somewhat smaller memory footprint.
1709 CONFIG_SYS_PROMPT_HUSH_PS2
1711 This defines the secondary prompt string, which is
1712 printed when the command interpreter needs more input
1713 to complete a command. Usually "> ".
1717 In the current implementation, the local variables
1718 space and global environment variables space are
1719 separated. Local variables are those you define by
1720 simply typing `name=value'. To access a local
1721 variable later on, you have write `$name' or
1722 `${name}'; to execute the contents of a variable
1723 directly type `$name' at the command prompt.
1725 Global environment variables are those you use
1726 setenv/printenv to work with. To run a command stored
1727 in such a variable, you need to use the run command,
1728 and you must not use the '$' sign to access them.
1730 To store commands and special characters in a
1731 variable, please use double quotation marks
1732 surrounding the whole text of the variable, instead
1733 of the backslashes before semicolons and special
1736 - Commandline Editing and History:
1737 CONFIG_CMDLINE_EDITING
1739 Enable editing and History functions for interactive
1740 commandline input operations
1742 - Default Environment:
1743 CONFIG_EXTRA_ENV_SETTINGS
1745 Define this to contain any number of null terminated
1746 strings (variable = value pairs) that will be part of
1747 the default environment compiled into the boot image.
1749 For example, place something like this in your
1750 board's config file:
1752 #define CONFIG_EXTRA_ENV_SETTINGS \
1756 Warning: This method is based on knowledge about the
1757 internal format how the environment is stored by the
1758 U-Boot code. This is NOT an official, exported
1759 interface! Although it is unlikely that this format
1760 will change soon, there is no guarantee either.
1761 You better know what you are doing here.
1763 Note: overly (ab)use of the default environment is
1764 discouraged. Make sure to check other ways to preset
1765 the environment like the autoscript function or the
1768 - DataFlash Support:
1769 CONFIG_HAS_DATAFLASH
1771 Defining this option enables DataFlash features and
1772 allows to read/write in Dataflash via the standard
1775 - SystemACE Support:
1778 Adding this option adds support for Xilinx SystemACE
1779 chips attached via some sort of local bus. The address
1780 of the chip must also be defined in the
1781 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1783 #define CONFIG_SYSTEMACE
1784 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1786 When SystemACE support is added, the "ace" device type
1787 becomes available to the fat commands, i.e. fatls.
1789 - TFTP Fixed UDP Port:
1792 If this is defined, the environment variable tftpsrcp
1793 is used to supply the TFTP UDP source port value.
1794 If tftpsrcp isn't defined, the normal pseudo-random port
1795 number generator is used.
1797 Also, the environment variable tftpdstp is used to supply
1798 the TFTP UDP destination port value. If tftpdstp isn't
1799 defined, the normal port 69 is used.
1801 The purpose for tftpsrcp is to allow a TFTP server to
1802 blindly start the TFTP transfer using the pre-configured
1803 target IP address and UDP port. This has the effect of
1804 "punching through" the (Windows XP) firewall, allowing
1805 the remainder of the TFTP transfer to proceed normally.
1806 A better solution is to properly configure the firewall,
1807 but sometimes that is not allowed.
1809 - Show boot progress:
1810 CONFIG_SHOW_BOOT_PROGRESS
1812 Defining this option allows to add some board-
1813 specific code (calling a user-provided function
1814 "show_boot_progress(int)") that enables you to show
1815 the system's boot progress on some display (for
1816 example, some LED's) on your board. At the moment,
1817 the following checkpoints are implemented:
1819 - Automatic software updates via TFTP server
1821 CONFIG_UPDATE_TFTP_CNT_MAX
1822 CONFIG_UPDATE_TFTP_MSEC_MAX
1824 These options enable and control the auto-update feature;
1825 for a more detailed description refer to doc/README.update.
1827 Legacy uImage format:
1830 1 common/cmd_bootm.c before attempting to boot an image
1831 -1 common/cmd_bootm.c Image header has bad magic number
1832 2 common/cmd_bootm.c Image header has correct magic number
1833 -2 common/cmd_bootm.c Image header has bad checksum
1834 3 common/cmd_bootm.c Image header has correct checksum
1835 -3 common/cmd_bootm.c Image data has bad checksum
1836 4 common/cmd_bootm.c Image data has correct checksum
1837 -4 common/cmd_bootm.c Image is for unsupported architecture
1838 5 common/cmd_bootm.c Architecture check OK
1839 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1840 6 common/cmd_bootm.c Image Type check OK
1841 -6 common/cmd_bootm.c gunzip uncompression error
1842 -7 common/cmd_bootm.c Unimplemented compression type
1843 7 common/cmd_bootm.c Uncompression OK
1844 8 common/cmd_bootm.c No uncompress/copy overwrite error
1845 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1847 9 common/image.c Start initial ramdisk verification
1848 -10 common/image.c Ramdisk header has bad magic number
1849 -11 common/image.c Ramdisk header has bad checksum
1850 10 common/image.c Ramdisk header is OK
1851 -12 common/image.c Ramdisk data has bad checksum
1852 11 common/image.c Ramdisk data has correct checksum
1853 12 common/image.c Ramdisk verification complete, start loading
1854 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1855 13 common/image.c Start multifile image verification
1856 14 common/image.c No initial ramdisk, no multifile, continue.
1858 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1860 -30 lib_ppc/board.c Fatal error, hang the system
1861 -31 post/post.c POST test failed, detected by post_output_backlog()
1862 -32 post/post.c POST test failed, detected by post_run_single()
1864 34 common/cmd_doc.c before loading a Image from a DOC device
1865 -35 common/cmd_doc.c Bad usage of "doc" command
1866 35 common/cmd_doc.c correct usage of "doc" command
1867 -36 common/cmd_doc.c No boot device
1868 36 common/cmd_doc.c correct boot device
1869 -37 common/cmd_doc.c Unknown Chip ID on boot device
1870 37 common/cmd_doc.c correct chip ID found, device available
1871 -38 common/cmd_doc.c Read Error on boot device
1872 38 common/cmd_doc.c reading Image header from DOC device OK
1873 -39 common/cmd_doc.c Image header has bad magic number
1874 39 common/cmd_doc.c Image header has correct magic number
1875 -40 common/cmd_doc.c Error reading Image from DOC device
1876 40 common/cmd_doc.c Image header has correct magic number
1877 41 common/cmd_ide.c before loading a Image from a IDE device
1878 -42 common/cmd_ide.c Bad usage of "ide" command
1879 42 common/cmd_ide.c correct usage of "ide" command
1880 -43 common/cmd_ide.c No boot device
1881 43 common/cmd_ide.c boot device found
1882 -44 common/cmd_ide.c Device not available
1883 44 common/cmd_ide.c Device available
1884 -45 common/cmd_ide.c wrong partition selected
1885 45 common/cmd_ide.c partition selected
1886 -46 common/cmd_ide.c Unknown partition table
1887 46 common/cmd_ide.c valid partition table found
1888 -47 common/cmd_ide.c Invalid partition type
1889 47 common/cmd_ide.c correct partition type
1890 -48 common/cmd_ide.c Error reading Image Header on boot device
1891 48 common/cmd_ide.c reading Image Header from IDE device OK
1892 -49 common/cmd_ide.c Image header has bad magic number
1893 49 common/cmd_ide.c Image header has correct magic number
1894 -50 common/cmd_ide.c Image header has bad checksum
1895 50 common/cmd_ide.c Image header has correct checksum
1896 -51 common/cmd_ide.c Error reading Image from IDE device
1897 51 common/cmd_ide.c reading Image from IDE device OK
1898 52 common/cmd_nand.c before loading a Image from a NAND device
1899 -53 common/cmd_nand.c Bad usage of "nand" command
1900 53 common/cmd_nand.c correct usage of "nand" command
1901 -54 common/cmd_nand.c No boot device
1902 54 common/cmd_nand.c boot device found
1903 -55 common/cmd_nand.c Unknown Chip ID on boot device
1904 55 common/cmd_nand.c correct chip ID found, device available
1905 -56 common/cmd_nand.c Error reading Image Header on boot device
1906 56 common/cmd_nand.c reading Image Header from NAND device OK
1907 -57 common/cmd_nand.c Image header has bad magic number
1908 57 common/cmd_nand.c Image header has correct magic number
1909 -58 common/cmd_nand.c Error reading Image from NAND device
1910 58 common/cmd_nand.c reading Image from NAND device OK
1912 -60 common/env_common.c Environment has a bad CRC, using default
1914 64 net/eth.c starting with Ethernet configuration.
1915 -64 net/eth.c no Ethernet found.
1916 65 net/eth.c Ethernet found.
1918 -80 common/cmd_net.c usage wrong
1919 80 common/cmd_net.c before calling NetLoop()
1920 -81 common/cmd_net.c some error in NetLoop() occurred
1921 81 common/cmd_net.c NetLoop() back without error
1922 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1923 82 common/cmd_net.c trying automatic boot
1924 83 common/cmd_net.c running autoscript
1925 -83 common/cmd_net.c some error in automatic boot or autoscript
1926 84 common/cmd_net.c end without errors
1931 100 common/cmd_bootm.c Kernel FIT Image has correct format
1932 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1933 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1934 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1935 102 common/cmd_bootm.c Kernel unit name specified
1936 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1937 103 common/cmd_bootm.c Found configuration node
1938 104 common/cmd_bootm.c Got kernel subimage node offset
1939 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1940 105 common/cmd_bootm.c Kernel subimage hash verification OK
1941 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1942 106 common/cmd_bootm.c Architecture check OK
1943 -106 common/cmd_bootm.c Kernel subimage has wrong type
1944 107 common/cmd_bootm.c Kernel subimage type OK
1945 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1946 108 common/cmd_bootm.c Got kernel subimage data/size
1947 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1948 -109 common/cmd_bootm.c Can't get kernel subimage type
1949 -110 common/cmd_bootm.c Can't get kernel subimage comp
1950 -111 common/cmd_bootm.c Can't get kernel subimage os
1951 -112 common/cmd_bootm.c Can't get kernel subimage load address
1952 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1954 120 common/image.c Start initial ramdisk verification
1955 -120 common/image.c Ramdisk FIT image has incorrect format
1956 121 common/image.c Ramdisk FIT image has correct format
1957 122 common/image.c No ramdisk subimage unit name, using configuration
1958 -122 common/image.c Can't get configuration for ramdisk subimage
1959 123 common/image.c Ramdisk unit name specified
1960 -124 common/image.c Can't get ramdisk subimage node offset
1961 125 common/image.c Got ramdisk subimage node offset
1962 -125 common/image.c Ramdisk subimage hash verification failed
1963 126 common/image.c Ramdisk subimage hash verification OK
1964 -126 common/image.c Ramdisk subimage for unsupported architecture
1965 127 common/image.c Architecture check OK
1966 -127 common/image.c Can't get ramdisk subimage data/size
1967 128 common/image.c Got ramdisk subimage data/size
1968 129 common/image.c Can't get ramdisk load address
1969 -129 common/image.c Got ramdisk load address
1971 -130 common/cmd_doc.c Incorrect FIT image format
1972 131 common/cmd_doc.c FIT image format OK
1974 -140 common/cmd_ide.c Incorrect FIT image format
1975 141 common/cmd_ide.c FIT image format OK
1977 -150 common/cmd_nand.c Incorrect FIT image format
1978 151 common/cmd_nand.c FIT image format OK
1984 [so far only for SMDK2400 and TRAB boards]
1986 - Modem support enable:
1987 CONFIG_MODEM_SUPPORT
1989 - RTS/CTS Flow control enable:
1992 - Modem debug support:
1993 CONFIG_MODEM_SUPPORT_DEBUG
1995 Enables debugging stuff (char screen[1024], dbg())
1996 for modem support. Useful only with BDI2000.
1998 - Interrupt support (PPC):
2000 There are common interrupt_init() and timer_interrupt()
2001 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2002 for CPU specific initialization. interrupt_init_cpu()
2003 should set decrementer_count to appropriate value. If
2004 CPU resets decrementer automatically after interrupt
2005 (ppc4xx) it should set decrementer_count to zero.
2006 timer_interrupt() calls timer_interrupt_cpu() for CPU
2007 specific handling. If board has watchdog / status_led
2008 / other_activity_monitor it works automatically from
2009 general timer_interrupt().
2013 In the target system modem support is enabled when a
2014 specific key (key combination) is pressed during
2015 power-on. Otherwise U-Boot will boot normally
2016 (autoboot). The key_pressed() function is called from
2017 board_init(). Currently key_pressed() is a dummy
2018 function, returning 1 and thus enabling modem
2021 If there are no modem init strings in the
2022 environment, U-Boot proceed to autoboot; the
2023 previous output (banner, info printfs) will be
2026 See also: doc/README.Modem
2029 Configuration Settings:
2030 -----------------------
2032 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2033 undefine this when you're short of memory.
2035 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2036 prompt for user input.
2038 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2040 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2042 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2044 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2045 the application (usually a Linux kernel) when it is
2048 - CONFIG_SYS_BAUDRATE_TABLE:
2049 List of legal baudrate settings for this board.
2051 - CONFIG_SYS_CONSOLE_INFO_QUIET
2052 Suppress display of console information at boot.
2054 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2055 If the board specific function
2056 extern int overwrite_console (void);
2057 returns 1, the stdin, stderr and stdout are switched to the
2058 serial port, else the settings in the environment are used.
2060 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2061 Enable the call to overwrite_console().
2063 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2064 Enable overwrite of previous console environment settings.
2066 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2067 Begin and End addresses of the area used by the
2070 - CONFIG_SYS_ALT_MEMTEST:
2071 Enable an alternate, more extensive memory test.
2073 - CONFIG_SYS_MEMTEST_SCRATCH:
2074 Scratch address used by the alternate memory test
2075 You only need to set this if address zero isn't writeable
2077 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2078 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2079 this specified memory area will get subtracted from the top
2080 (end) of RAM and won't get "touched" at all by U-Boot. By
2081 fixing up gd->ram_size the Linux kernel should gets passed
2082 the now "corrected" memory size and won't touch it either.
2083 This should work for arch/ppc and arch/powerpc. Only Linux
2084 board ports in arch/powerpc with bootwrapper support that
2085 recalculate the memory size from the SDRAM controller setup
2086 will have to get fixed in Linux additionally.
2088 This option can be used as a workaround for the 440EPx/GRx
2089 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2092 WARNING: Please make sure that this value is a multiple of
2093 the Linux page size (normally 4k). If this is not the case,
2094 then the end address of the Linux memory will be located at a
2095 non page size aligned address and this could cause major
2098 - CONFIG_SYS_TFTP_LOADADDR:
2099 Default load address for network file downloads
2101 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2102 Enable temporary baudrate change while serial download
2104 - CONFIG_SYS_SDRAM_BASE:
2105 Physical start address of SDRAM. _Must_ be 0 here.
2107 - CONFIG_SYS_MBIO_BASE:
2108 Physical start address of Motherboard I/O (if using a
2111 - CONFIG_SYS_FLASH_BASE:
2112 Physical start address of Flash memory.
2114 - CONFIG_SYS_MONITOR_BASE:
2115 Physical start address of boot monitor code (set by
2116 make config files to be same as the text base address
2117 (TEXT_BASE) used when linking) - same as
2118 CONFIG_SYS_FLASH_BASE when booting from flash.
2120 - CONFIG_SYS_MONITOR_LEN:
2121 Size of memory reserved for monitor code, used to
2122 determine _at_compile_time_ (!) if the environment is
2123 embedded within the U-Boot image, or in a separate
2126 - CONFIG_SYS_MALLOC_LEN:
2127 Size of DRAM reserved for malloc() use.
2129 - CONFIG_SYS_BOOTM_LEN:
2130 Normally compressed uImages are limited to an
2131 uncompressed size of 8 MBytes. If this is not enough,
2132 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2133 to adjust this setting to your needs.
2135 - CONFIG_SYS_BOOTMAPSZ:
2136 Maximum size of memory mapped by the startup code of
2137 the Linux kernel; all data that must be processed by
2138 the Linux kernel (bd_info, boot arguments, FDT blob if
2139 used) must be put below this limit, unless "bootm_low"
2140 enviroment variable is defined and non-zero. In such case
2141 all data for the Linux kernel must be between "bootm_low"
2142 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2144 - CONFIG_SYS_MAX_FLASH_BANKS:
2145 Max number of Flash memory banks
2147 - CONFIG_SYS_MAX_FLASH_SECT:
2148 Max number of sectors on a Flash chip
2150 - CONFIG_SYS_FLASH_ERASE_TOUT:
2151 Timeout for Flash erase operations (in ms)
2153 - CONFIG_SYS_FLASH_WRITE_TOUT:
2154 Timeout for Flash write operations (in ms)
2156 - CONFIG_SYS_FLASH_LOCK_TOUT
2157 Timeout for Flash set sector lock bit operation (in ms)
2159 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2160 Timeout for Flash clear lock bits operation (in ms)
2162 - CONFIG_SYS_FLASH_PROTECTION
2163 If defined, hardware flash sectors protection is used
2164 instead of U-Boot software protection.
2166 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2168 Enable TFTP transfers directly to flash memory;
2169 without this option such a download has to be
2170 performed in two steps: (1) download to RAM, and (2)
2171 copy from RAM to flash.
2173 The two-step approach is usually more reliable, since
2174 you can check if the download worked before you erase
2175 the flash, but in some situations (when system RAM is
2176 too limited to allow for a temporary copy of the
2177 downloaded image) this option may be very useful.
2179 - CONFIG_SYS_FLASH_CFI:
2180 Define if the flash driver uses extra elements in the
2181 common flash structure for storing flash geometry.
2183 - CONFIG_FLASH_CFI_DRIVER
2184 This option also enables the building of the cfi_flash driver
2185 in the drivers directory
2187 - CONFIG_FLASH_CFI_MTD
2188 This option enables the building of the cfi_mtd driver
2189 in the drivers directory. The driver exports CFI flash
2192 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2193 Use buffered writes to flash.
2195 - CONFIG_FLASH_SPANSION_S29WS_N
2196 s29ws-n MirrorBit flash has non-standard addresses for buffered
2199 - CONFIG_SYS_FLASH_QUIET_TEST
2200 If this option is defined, the common CFI flash doesn't
2201 print it's warning upon not recognized FLASH banks. This
2202 is useful, if some of the configured banks are only
2203 optionally available.
2205 - CONFIG_FLASH_SHOW_PROGRESS
2206 If defined (must be an integer), print out countdown
2207 digits and dots. Recommended value: 45 (9..1) for 80
2208 column displays, 15 (3..1) for 40 column displays.
2210 - CONFIG_SYS_RX_ETH_BUFFER:
2211 Defines the number of Ethernet receive buffers. On some
2212 Ethernet controllers it is recommended to set this value
2213 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2214 buffers can be full shortly after enabling the interface
2215 on high Ethernet traffic.
2216 Defaults to 4 if not defined.
2218 The following definitions that deal with the placement and management
2219 of environment data (variable area); in general, we support the
2220 following configurations:
2222 - CONFIG_ENV_IS_IN_FLASH:
2224 Define this if the environment is in flash memory.
2226 a) The environment occupies one whole flash sector, which is
2227 "embedded" in the text segment with the U-Boot code. This
2228 happens usually with "bottom boot sector" or "top boot
2229 sector" type flash chips, which have several smaller
2230 sectors at the start or the end. For instance, such a
2231 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2232 such a case you would place the environment in one of the
2233 4 kB sectors - with U-Boot code before and after it. With
2234 "top boot sector" type flash chips, you would put the
2235 environment in one of the last sectors, leaving a gap
2236 between U-Boot and the environment.
2238 - CONFIG_ENV_OFFSET:
2240 Offset of environment data (variable area) to the
2241 beginning of flash memory; for instance, with bottom boot
2242 type flash chips the second sector can be used: the offset
2243 for this sector is given here.
2245 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2249 This is just another way to specify the start address of
2250 the flash sector containing the environment (instead of
2253 - CONFIG_ENV_SECT_SIZE:
2255 Size of the sector containing the environment.
2258 b) Sometimes flash chips have few, equal sized, BIG sectors.
2259 In such a case you don't want to spend a whole sector for
2264 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2265 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2266 of this flash sector for the environment. This saves
2267 memory for the RAM copy of the environment.
2269 It may also save flash memory if you decide to use this
2270 when your environment is "embedded" within U-Boot code,
2271 since then the remainder of the flash sector could be used
2272 for U-Boot code. It should be pointed out that this is
2273 STRONGLY DISCOURAGED from a robustness point of view:
2274 updating the environment in flash makes it always
2275 necessary to erase the WHOLE sector. If something goes
2276 wrong before the contents has been restored from a copy in
2277 RAM, your target system will be dead.
2279 - CONFIG_ENV_ADDR_REDUND
2280 CONFIG_ENV_SIZE_REDUND
2282 These settings describe a second storage area used to hold
2283 a redundant copy of the environment data, so that there is
2284 a valid backup copy in case there is a power failure during
2285 a "saveenv" operation.
2287 BE CAREFUL! Any changes to the flash layout, and some changes to the
2288 source code will make it necessary to adapt <board>/u-boot.lds*
2292 - CONFIG_ENV_IS_IN_NVRAM:
2294 Define this if you have some non-volatile memory device
2295 (NVRAM, battery buffered SRAM) which you want to use for the
2301 These two #defines are used to determine the memory area you
2302 want to use for environment. It is assumed that this memory
2303 can just be read and written to, without any special
2306 BE CAREFUL! The first access to the environment happens quite early
2307 in U-Boot initalization (when we try to get the setting of for the
2308 console baudrate). You *MUST* have mapped your NVRAM area then, or
2311 Please note that even with NVRAM we still use a copy of the
2312 environment in RAM: we could work on NVRAM directly, but we want to
2313 keep settings there always unmodified except somebody uses "saveenv"
2314 to save the current settings.
2317 - CONFIG_ENV_IS_IN_EEPROM:
2319 Use this if you have an EEPROM or similar serial access
2320 device and a driver for it.
2322 - CONFIG_ENV_OFFSET:
2325 These two #defines specify the offset and size of the
2326 environment area within the total memory of your EEPROM.
2328 - CONFIG_SYS_I2C_EEPROM_ADDR:
2329 If defined, specified the chip address of the EEPROM device.
2330 The default address is zero.
2332 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2333 If defined, the number of bits used to address bytes in a
2334 single page in the EEPROM device. A 64 byte page, for example
2335 would require six bits.
2337 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2338 If defined, the number of milliseconds to delay between
2339 page writes. The default is zero milliseconds.
2341 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2342 The length in bytes of the EEPROM memory array address. Note
2343 that this is NOT the chip address length!
2345 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2346 EEPROM chips that implement "address overflow" are ones
2347 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2348 address and the extra bits end up in the "chip address" bit
2349 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2352 Note that we consider the length of the address field to
2353 still be one byte because the extra address bits are hidden
2354 in the chip address.
2356 - CONFIG_SYS_EEPROM_SIZE:
2357 The size in bytes of the EEPROM device.
2360 - CONFIG_ENV_IS_IN_DATAFLASH:
2362 Define this if you have a DataFlash memory device which you
2363 want to use for the environment.
2365 - CONFIG_ENV_OFFSET:
2369 These three #defines specify the offset and size of the
2370 environment area within the total memory of your DataFlash placed
2371 at the specified address.
2373 - CONFIG_ENV_IS_IN_NAND:
2375 Define this if you have a NAND device which you want to use
2376 for the environment.
2378 - CONFIG_ENV_OFFSET:
2381 These two #defines specify the offset and size of the environment
2382 area within the first NAND device.
2384 - CONFIG_ENV_OFFSET_REDUND
2386 This setting describes a second storage area of CONFIG_ENV_SIZE
2387 size used to hold a redundant copy of the environment data,
2388 so that there is a valid backup copy in case there is a
2389 power failure during a "saveenv" operation.
2391 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2392 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2393 the NAND devices block size.
2395 - CONFIG_SYS_SPI_INIT_OFFSET
2397 Defines offset to the initial SPI buffer area in DPRAM. The
2398 area is used at an early stage (ROM part) if the environment
2399 is configured to reside in the SPI EEPROM: We need a 520 byte
2400 scratch DPRAM area. It is used between the two initialization
2401 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2402 to be a good choice since it makes it far enough from the
2403 start of the data area as well as from the stack pointer.
2405 Please note that the environment is read-only until the monitor
2406 has been relocated to RAM and a RAM copy of the environment has been
2407 created; also, when using EEPROM you will have to use getenv_r()
2408 until then to read environment variables.
2410 The environment is protected by a CRC32 checksum. Before the monitor
2411 is relocated into RAM, as a result of a bad CRC you will be working
2412 with the compiled-in default environment - *silently*!!! [This is
2413 necessary, because the first environment variable we need is the
2414 "baudrate" setting for the console - if we have a bad CRC, we don't
2415 have any device yet where we could complain.]
2417 Note: once the monitor has been relocated, then it will complain if
2418 the default environment is used; a new CRC is computed as soon as you
2419 use the "saveenv" command to store a valid environment.
2421 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2422 Echo the inverted Ethernet link state to the fault LED.
2424 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2425 also needs to be defined.
2427 - CONFIG_SYS_FAULT_MII_ADDR:
2428 MII address of the PHY to check for the Ethernet link state.
2430 - CONFIG_SYS_64BIT_VSPRINTF:
2431 Makes vsprintf (and all *printf functions) support printing
2432 of 64bit values by using the L quantifier
2434 - CONFIG_SYS_64BIT_STRTOUL:
2435 Adds simple_strtoull that returns a 64bit value
2437 Low Level (hardware related) configuration options:
2438 ---------------------------------------------------
2440 - CONFIG_SYS_CACHELINE_SIZE:
2441 Cache Line Size of the CPU.
2443 - CONFIG_SYS_DEFAULT_IMMR:
2444 Default address of the IMMR after system reset.
2446 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2447 and RPXsuper) to be able to adjust the position of
2448 the IMMR register after a reset.
2450 - Floppy Disk Support:
2451 CONFIG_SYS_FDC_DRIVE_NUMBER
2453 the default drive number (default value 0)
2455 CONFIG_SYS_ISA_IO_STRIDE
2457 defines the spacing between FDC chipset registers
2460 CONFIG_SYS_ISA_IO_OFFSET
2462 defines the offset of register from address. It
2463 depends on which part of the data bus is connected to
2464 the FDC chipset. (default value 0)
2466 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2467 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2470 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2471 fdc_hw_init() is called at the beginning of the FDC
2472 setup. fdc_hw_init() must be provided by the board
2473 source code. It is used to make hardware dependant
2476 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2477 DO NOT CHANGE unless you know exactly what you're
2478 doing! (11-4) [MPC8xx/82xx systems only]
2480 - CONFIG_SYS_INIT_RAM_ADDR:
2482 Start address of memory area that can be used for
2483 initial data and stack; please note that this must be
2484 writable memory that is working WITHOUT special
2485 initialization, i. e. you CANNOT use normal RAM which
2486 will become available only after programming the
2487 memory controller and running certain initialization
2490 U-Boot uses the following memory types:
2491 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2492 - MPC824X: data cache
2493 - PPC4xx: data cache
2495 - CONFIG_SYS_GBL_DATA_OFFSET:
2497 Offset of the initial data structure in the memory
2498 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2499 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2500 data is located at the end of the available space
2501 (sometimes written as (CONFIG_SYS_INIT_RAM_END -
2502 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2503 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2504 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2507 On the MPC824X (or other systems that use the data
2508 cache for initial memory) the address chosen for
2509 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2510 point to an otherwise UNUSED address space between
2511 the top of RAM and the start of the PCI space.
2513 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2515 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2517 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2519 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2521 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2523 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2525 - CONFIG_SYS_OR_TIMING_SDRAM:
2528 - CONFIG_SYS_MAMR_PTA:
2529 periodic timer for refresh
2531 - CONFIG_SYS_DER: Debug Event Register (37-47)
2533 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2534 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2535 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2536 CONFIG_SYS_BR1_PRELIM:
2537 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2539 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2540 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2541 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2542 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2544 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2545 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2546 Machine Mode Register and Memory Periodic Timer
2547 Prescaler definitions (SDRAM timing)
2549 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2550 enable I2C microcode relocation patch (MPC8xx);
2551 define relocation offset in DPRAM [DSP2]
2553 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2554 enable SMC microcode relocation patch (MPC8xx);
2555 define relocation offset in DPRAM [SMC1]
2557 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2558 enable SPI microcode relocation patch (MPC8xx);
2559 define relocation offset in DPRAM [SCC4]
2561 - CONFIG_SYS_USE_OSCCLK:
2562 Use OSCM clock mode on MBX8xx board. Be careful,
2563 wrong setting might damage your board. Read
2564 doc/README.MBX before setting this variable!
2566 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2567 Offset of the bootmode word in DPRAM used by post
2568 (Power On Self Tests). This definition overrides
2569 #define'd default value in commproc.h resp.
2572 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2573 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2574 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2575 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2576 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2577 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2578 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2579 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2580 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2583 Get DDR timing information from an I2C EEPROM. Common
2584 with pluggable memory modules such as SODIMMs
2587 I2C address of the SPD EEPROM
2589 - CONFIG_SYS_SPD_BUS_NUM
2590 If SPD EEPROM is on an I2C bus other than the first
2591 one, specify here. Note that the value must resolve
2592 to something your driver can deal with.
2594 - CONFIG_SYS_83XX_DDR_USES_CS0
2595 Only for 83xx systems. If specified, then DDR should
2596 be configured using CS0 and CS1 instead of CS2 and CS3.
2598 - CONFIG_SYS_83XX_DDR_USES_CS0
2599 Only for 83xx systems. If specified, then DDR should
2600 be configured using CS0 and CS1 instead of CS2 and CS3.
2602 - CONFIG_ETHER_ON_FEC[12]
2603 Define to enable FEC[12] on a 8xx series processor.
2605 - CONFIG_FEC[12]_PHY
2606 Define to the hardcoded PHY address which corresponds
2607 to the given FEC; i. e.
2608 #define CONFIG_FEC1_PHY 4
2609 means that the PHY with address 4 is connected to FEC1
2611 When set to -1, means to probe for first available.
2613 - CONFIG_FEC[12]_PHY_NORXERR
2614 The PHY does not have a RXERR line (RMII only).
2615 (so program the FEC to ignore it).
2618 Enable RMII mode for all FECs.
2619 Note that this is a global option, we can't
2620 have one FEC in standard MII mode and another in RMII mode.
2622 - CONFIG_CRC32_VERIFY
2623 Add a verify option to the crc32 command.
2626 => crc32 -v <address> <count> <crc32>
2628 Where address/count indicate a memory area
2629 and crc32 is the correct crc32 which the
2633 Add the "loopw" memory command. This only takes effect if
2634 the memory commands are activated globally (CONFIG_CMD_MEM).
2637 Add the "mdc" and "mwc" memory commands. These are cyclic
2642 This command will print 4 bytes (10,11,12,13) each 500 ms.
2644 => mwc.l 100 12345678 10
2645 This command will write 12345678 to address 100 all 10 ms.
2647 This only takes effect if the memory commands are activated
2648 globally (CONFIG_CMD_MEM).
2650 - CONFIG_SKIP_LOWLEVEL_INIT
2651 - CONFIG_SKIP_RELOCATE_UBOOT
2653 [ARM only] If these variables are defined, then
2654 certain low level initializations (like setting up
2655 the memory controller) are omitted and/or U-Boot does
2656 not relocate itself into RAM.
2657 Normally these variables MUST NOT be defined. The
2658 only exception is when U-Boot is loaded (to RAM) by
2659 some other boot loader or by a debugger which
2660 performs these initializations itself.
2663 Building the Software:
2664 ======================
2666 Building U-Boot has been tested in several native build environments
2667 and in many different cross environments. Of course we cannot support
2668 all possibly existing versions of cross development tools in all
2669 (potentially obsolete) versions. In case of tool chain problems we
2670 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2671 which is extensively used to build and test U-Boot.
2673 If you are not using a native environment, it is assumed that you
2674 have GNU cross compiling tools available in your path. In this case,
2675 you must set the environment variable CROSS_COMPILE in your shell.
2676 Note that no changes to the Makefile or any other source files are
2677 necessary. For example using the ELDK on a 4xx CPU, please enter:
2679 $ CROSS_COMPILE=ppc_4xx-
2680 $ export CROSS_COMPILE
2682 U-Boot is intended to be simple to build. After installing the
2683 sources you must configure U-Boot for one specific board type. This
2688 where "NAME_config" is the name of one of the existing configu-
2689 rations; see the main Makefile for supported names.
2691 Note: for some board special configuration names may exist; check if
2692 additional information is available from the board vendor; for
2693 instance, the TQM823L systems are available without (standard)
2694 or with LCD support. You can select such additional "features"
2695 when choosing the configuration, i. e.
2698 - will configure for a plain TQM823L, i. e. no LCD support
2700 make TQM823L_LCD_config
2701 - will configure for a TQM823L with U-Boot console on LCD
2706 Finally, type "make all", and you should get some working U-Boot
2707 images ready for download to / installation on your system:
2709 - "u-boot.bin" is a raw binary image
2710 - "u-boot" is an image in ELF binary format
2711 - "u-boot.srec" is in Motorola S-Record format
2713 By default the build is performed locally and the objects are saved
2714 in the source directory. One of the two methods can be used to change
2715 this behavior and build U-Boot to some external directory:
2717 1. Add O= to the make command line invocations:
2719 make O=/tmp/build distclean
2720 make O=/tmp/build NAME_config
2721 make O=/tmp/build all
2723 2. Set environment variable BUILD_DIR to point to the desired location:
2725 export BUILD_DIR=/tmp/build
2730 Note that the command line "O=" setting overrides the BUILD_DIR environment
2734 Please be aware that the Makefiles assume you are using GNU make, so
2735 for instance on NetBSD you might need to use "gmake" instead of
2739 If the system board that you have is not listed, then you will need
2740 to port U-Boot to your hardware platform. To do this, follow these
2743 1. Add a new configuration option for your board to the toplevel
2744 "Makefile" and to the "MAKEALL" script, using the existing
2745 entries as examples. Note that here and at many other places
2746 boards and other names are listed in alphabetical sort order. Please
2748 2. Create a new directory to hold your board specific code. Add any
2749 files you need. In your board directory, you will need at least
2750 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2751 3. Create a new configuration file "include/configs/<board>.h" for
2753 3. If you're porting U-Boot to a new CPU, then also create a new
2754 directory to hold your CPU specific code. Add any files you need.
2755 4. Run "make <board>_config" with your new name.
2756 5. Type "make", and you should get a working "u-boot.srec" file
2757 to be installed on your target system.
2758 6. Debug and solve any problems that might arise.
2759 [Of course, this last step is much harder than it sounds.]
2762 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2763 ==============================================================
2765 If you have modified U-Boot sources (for instance added a new board
2766 or support for new devices, a new CPU, etc.) you are expected to
2767 provide feedback to the other developers. The feedback normally takes
2768 the form of a "patch", i. e. a context diff against a certain (latest
2769 official or latest in the git repository) version of U-Boot sources.
2771 But before you submit such a patch, please verify that your modifi-
2772 cation did not break existing code. At least make sure that *ALL* of
2773 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2774 just run the "MAKEALL" script, which will configure and build U-Boot
2775 for ALL supported system. Be warned, this will take a while. You can
2776 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2777 environment variable to the script, i. e. to use the ELDK cross tools
2780 CROSS_COMPILE=ppc_8xx- MAKEALL
2782 or to build on a native PowerPC system you can type
2784 CROSS_COMPILE=' ' MAKEALL
2786 When using the MAKEALL script, the default behaviour is to build
2787 U-Boot in the source directory. This location can be changed by
2788 setting the BUILD_DIR environment variable. Also, for each target
2789 built, the MAKEALL script saves two log files (<target>.ERR and
2790 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2791 location can be changed by setting the MAKEALL_LOGDIR environment
2792 variable. For example:
2794 export BUILD_DIR=/tmp/build
2795 export MAKEALL_LOGDIR=/tmp/log
2796 CROSS_COMPILE=ppc_8xx- MAKEALL
2798 With the above settings build objects are saved in the /tmp/build,
2799 log files are saved in the /tmp/log and the source tree remains clean
2800 during the whole build process.
2803 See also "U-Boot Porting Guide" below.
2806 Monitor Commands - Overview:
2807 ============================
2809 go - start application at address 'addr'
2810 run - run commands in an environment variable
2811 bootm - boot application image from memory
2812 bootp - boot image via network using BootP/TFTP protocol
2813 tftpboot- boot image via network using TFTP protocol
2814 and env variables "ipaddr" and "serverip"
2815 (and eventually "gatewayip")
2816 rarpboot- boot image via network using RARP/TFTP protocol
2817 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2818 loads - load S-Record file over serial line
2819 loadb - load binary file over serial line (kermit mode)
2821 mm - memory modify (auto-incrementing)
2822 nm - memory modify (constant address)
2823 mw - memory write (fill)
2825 cmp - memory compare
2826 crc32 - checksum calculation
2827 imd - i2c memory display
2828 imm - i2c memory modify (auto-incrementing)
2829 inm - i2c memory modify (constant address)
2830 imw - i2c memory write (fill)
2831 icrc32 - i2c checksum calculation
2832 iprobe - probe to discover valid I2C chip addresses
2833 iloop - infinite loop on address range
2834 isdram - print SDRAM configuration information
2835 sspi - SPI utility commands
2836 base - print or set address offset
2837 printenv- print environment variables
2838 setenv - set environment variables
2839 saveenv - save environment variables to persistent storage
2840 protect - enable or disable FLASH write protection
2841 erase - erase FLASH memory
2842 flinfo - print FLASH memory information
2843 bdinfo - print Board Info structure
2844 iminfo - print header information for application image
2845 coninfo - print console devices and informations
2846 ide - IDE sub-system
2847 loop - infinite loop on address range
2848 loopw - infinite write loop on address range
2849 mtest - simple RAM test
2850 icache - enable or disable instruction cache
2851 dcache - enable or disable data cache
2852 reset - Perform RESET of the CPU
2853 echo - echo args to console
2854 version - print monitor version
2855 help - print online help
2856 ? - alias for 'help'
2859 Monitor Commands - Detailed Description:
2860 ========================================
2864 For now: just type "help <command>".
2867 Environment Variables:
2868 ======================
2870 U-Boot supports user configuration using Environment Variables which
2871 can be made persistent by saving to Flash memory.
2873 Environment Variables are set using "setenv", printed using
2874 "printenv", and saved to Flash using "saveenv". Using "setenv"
2875 without a value can be used to delete a variable from the
2876 environment. As long as you don't save the environment you are
2877 working with an in-memory copy. In case the Flash area containing the
2878 environment is erased by accident, a default environment is provided.
2880 Some configuration options can be set using Environment Variables:
2882 baudrate - see CONFIG_BAUDRATE
2884 bootdelay - see CONFIG_BOOTDELAY
2886 bootcmd - see CONFIG_BOOTCOMMAND
2888 bootargs - Boot arguments when booting an RTOS image
2890 bootfile - Name of the image to load with TFTP
2892 bootm_low - Memory range available for image processing in the bootm
2893 command can be restricted. This variable is given as
2894 a hexadecimal number and defines lowest address allowed
2895 for use by the bootm command. See also "bootm_size"
2896 environment variable. Address defined by "bootm_low" is
2897 also the base of the initial memory mapping for the Linux
2898 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
2900 bootm_size - Memory range available for image processing in the bootm
2901 command can be restricted. This variable is given as
2902 a hexadecimal number and defines the size of the region
2903 allowed for use by the bootm command. See also "bootm_low"
2904 environment variable.
2906 updatefile - Location of the software update file on a TFTP server, used
2907 by the automatic software update feature. Please refer to
2908 documentation in doc/README.update for more details.
2910 autoload - if set to "no" (any string beginning with 'n'),
2911 "bootp" will just load perform a lookup of the
2912 configuration from the BOOTP server, but not try to
2913 load any image using TFTP
2915 autoscript - if set to "yes" commands like "loadb", "loady",
2916 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2917 to automatically run script images (by internally
2918 calling "autoscript").
2920 autoscript_uname - if script image is in a format (FIT) this
2921 variable is used to get script subimage unit name.
2923 autostart - if set to "yes", an image loaded using the "bootp",
2924 "rarpboot", "tftpboot" or "diskboot" commands will
2925 be automatically started (by internally calling
2928 If set to "no", a standalone image passed to the
2929 "bootm" command will be copied to the load address
2930 (and eventually uncompressed), but NOT be started.
2931 This can be used to load and uncompress arbitrary
2934 i2cfast - (PPC405GP|PPC405EP only)
2935 if set to 'y' configures Linux I2C driver for fast
2936 mode (400kHZ). This environment variable is used in
2937 initialization code. So, for changes to be effective
2938 it must be saved and board must be reset.
2940 initrd_high - restrict positioning of initrd images:
2941 If this variable is not set, initrd images will be
2942 copied to the highest possible address in RAM; this
2943 is usually what you want since it allows for
2944 maximum initrd size. If for some reason you want to
2945 make sure that the initrd image is loaded below the
2946 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
2947 variable to a value of "no" or "off" or "0".
2948 Alternatively, you can set it to a maximum upper
2949 address to use (U-Boot will still check that it
2950 does not overwrite the U-Boot stack and data).
2952 For instance, when you have a system with 16 MB
2953 RAM, and want to reserve 4 MB from use by Linux,
2954 you can do this by adding "mem=12M" to the value of
2955 the "bootargs" variable. However, now you must make
2956 sure that the initrd image is placed in the first
2957 12 MB as well - this can be done with
2959 setenv initrd_high 00c00000
2961 If you set initrd_high to 0xFFFFFFFF, this is an
2962 indication to U-Boot that all addresses are legal
2963 for the Linux kernel, including addresses in flash
2964 memory. In this case U-Boot will NOT COPY the
2965 ramdisk at all. This may be useful to reduce the
2966 boot time on your system, but requires that this
2967 feature is supported by your Linux kernel.
2969 ipaddr - IP address; needed for tftpboot command
2971 loadaddr - Default load address for commands like "bootp",
2972 "rarpboot", "tftpboot", "loadb" or "diskboot"
2974 loads_echo - see CONFIG_LOADS_ECHO
2976 serverip - TFTP server IP address; needed for tftpboot command
2978 bootretry - see CONFIG_BOOT_RETRY_TIME
2980 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2982 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2984 ethprime - When CONFIG_NET_MULTI is enabled controls which
2985 interface is used first.
2987 ethact - When CONFIG_NET_MULTI is enabled controls which
2988 interface is currently active. For example you
2989 can do the following
2991 => setenv ethact FEC ETHERNET
2992 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2993 => setenv ethact SCC ETHERNET
2994 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2996 ethrotate - When set to "no" U-Boot does not go through all
2997 available network interfaces.
2998 It just stays at the currently selected interface.
3000 netretry - When set to "no" each network operation will
3001 either succeed or fail without retrying.
3002 When set to "once" the network operation will
3003 fail when all the available network interfaces
3004 are tried once without success.
3005 Useful on scripts which control the retry operation
3008 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
3009 if set load address for the NPE microcode
3011 tftpsrcport - If this is set, the value is used for TFTP's
3014 tftpdstport - If this is set, the value is used for TFTP's UDP
3015 destination port instead of the Well Know Port 69.
3017 vlan - When set to a value < 4095 the traffic over
3018 Ethernet is encapsulated/received over 802.1q
3021 The following environment variables may be used and automatically
3022 updated by the network boot commands ("bootp" and "rarpboot"),
3023 depending the information provided by your boot server:
3025 bootfile - see above
3026 dnsip - IP address of your Domain Name Server
3027 dnsip2 - IP address of your secondary Domain Name Server
3028 gatewayip - IP address of the Gateway (Router) to use
3029 hostname - Target hostname
3031 netmask - Subnet Mask
3032 rootpath - Pathname of the root filesystem on the NFS server
3033 serverip - see above
3036 There are two special Environment Variables:
3038 serial# - contains hardware identification information such
3039 as type string and/or serial number
3040 ethaddr - Ethernet address
3042 These variables can be set only once (usually during manufacturing of
3043 the board). U-Boot refuses to delete or overwrite these variables
3044 once they have been set once.
3047 Further special Environment Variables:
3049 ver - Contains the U-Boot version string as printed
3050 with the "version" command. This variable is
3051 readonly (see CONFIG_VERSION_VARIABLE).
3054 Please note that changes to some configuration parameters may take
3055 only effect after the next boot (yes, that's just like Windoze :-).
3058 Command Line Parsing:
3059 =====================
3061 There are two different command line parsers available with U-Boot:
3062 the old "simple" one, and the much more powerful "hush" shell:
3064 Old, simple command line parser:
3065 --------------------------------
3067 - supports environment variables (through setenv / saveenv commands)
3068 - several commands on one line, separated by ';'
3069 - variable substitution using "... ${name} ..." syntax
3070 - special characters ('$', ';') can be escaped by prefixing with '\',
3072 setenv bootcmd bootm \${address}
3073 - You can also escape text by enclosing in single apostrophes, for example:
3074 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3079 - similar to Bourne shell, with control structures like
3080 if...then...else...fi, for...do...done; while...do...done,
3081 until...do...done, ...
3082 - supports environment ("global") variables (through setenv / saveenv
3083 commands) and local shell variables (through standard shell syntax
3084 "name=value"); only environment variables can be used with "run"
3090 (1) If a command line (or an environment variable executed by a "run"
3091 command) contains several commands separated by semicolon, and
3092 one of these commands fails, then the remaining commands will be
3095 (2) If you execute several variables with one call to run (i. e.
3096 calling run with a list of variables as arguments), any failing
3097 command will cause "run" to terminate, i. e. the remaining
3098 variables are not executed.
3100 Note for Redundant Ethernet Interfaces:
3101 =======================================
3103 Some boards come with redundant Ethernet interfaces; U-Boot supports
3104 such configurations and is capable of automatic selection of a
3105 "working" interface when needed. MAC assignment works as follows:
3107 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3108 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3109 "eth1addr" (=>eth1), "eth2addr", ...
3111 If the network interface stores some valid MAC address (for instance
3112 in SROM), this is used as default address if there is NO correspon-
3113 ding setting in the environment; if the corresponding environment
3114 variable is set, this overrides the settings in the card; that means:
3116 o If the SROM has a valid MAC address, and there is no address in the
3117 environment, the SROM's address is used.
3119 o If there is no valid address in the SROM, and a definition in the
3120 environment exists, then the value from the environment variable is
3123 o If both the SROM and the environment contain a MAC address, and
3124 both addresses are the same, this MAC address is used.
3126 o If both the SROM and the environment contain a MAC address, and the
3127 addresses differ, the value from the environment is used and a
3130 o If neither SROM nor the environment contain a MAC address, an error
3137 U-Boot is capable of booting (and performing other auxiliary operations on)
3138 images in two formats:
3140 New uImage format (FIT)
3141 -----------------------
3143 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3144 to Flattened Device Tree). It allows the use of images with multiple
3145 components (several kernels, ramdisks, etc.), with contents protected by
3146 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3152 Old image format is based on binary files which can be basically anything,
3153 preceded by a special header; see the definitions in include/image.h for
3154 details; basically, the header defines the following image properties:
3156 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3157 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3158 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3159 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3161 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3162 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3163 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3164 * Compression Type (uncompressed, gzip, bzip2)
3170 The header is marked by a special Magic Number, and both the header
3171 and the data portions of the image are secured against corruption by
3178 Although U-Boot should support any OS or standalone application
3179 easily, the main focus has always been on Linux during the design of
3182 U-Boot includes many features that so far have been part of some
3183 special "boot loader" code within the Linux kernel. Also, any
3184 "initrd" images to be used are no longer part of one big Linux image;
3185 instead, kernel and "initrd" are separate images. This implementation
3186 serves several purposes:
3188 - the same features can be used for other OS or standalone
3189 applications (for instance: using compressed images to reduce the
3190 Flash memory footprint)
3192 - it becomes much easier to port new Linux kernel versions because
3193 lots of low-level, hardware dependent stuff are done by U-Boot
3195 - the same Linux kernel image can now be used with different "initrd"
3196 images; of course this also means that different kernel images can
3197 be run with the same "initrd". This makes testing easier (you don't
3198 have to build a new "zImage.initrd" Linux image when you just
3199 change a file in your "initrd"). Also, a field-upgrade of the
3200 software is easier now.
3206 Porting Linux to U-Boot based systems:
3207 ---------------------------------------
3209 U-Boot cannot save you from doing all the necessary modifications to
3210 configure the Linux device drivers for use with your target hardware
3211 (no, we don't intend to provide a full virtual machine interface to
3214 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3216 Just make sure your machine specific header file (for instance
3217 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3218 Information structure as we define in include/asm-<arch>/u-boot.h,
3219 and make sure that your definition of IMAP_ADDR uses the same value
3220 as your U-Boot configuration in CONFIG_SYS_IMMR.
3223 Configuring the Linux kernel:
3224 -----------------------------
3226 No specific requirements for U-Boot. Make sure you have some root
3227 device (initial ramdisk, NFS) for your target system.
3230 Building a Linux Image:
3231 -----------------------
3233 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3234 not used. If you use recent kernel source, a new build target
3235 "uImage" will exist which automatically builds an image usable by
3236 U-Boot. Most older kernels also have support for a "pImage" target,
3237 which was introduced for our predecessor project PPCBoot and uses a
3238 100% compatible format.
3247 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3248 encapsulate a compressed Linux kernel image with header information,
3249 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3251 * build a standard "vmlinux" kernel image (in ELF binary format):
3253 * convert the kernel into a raw binary image:
3255 ${CROSS_COMPILE}-objcopy -O binary \
3256 -R .note -R .comment \
3257 -S vmlinux linux.bin
3259 * compress the binary image:
3263 * package compressed binary image for U-Boot:
3265 mkimage -A ppc -O linux -T kernel -C gzip \
3266 -a 0 -e 0 -n "Linux Kernel Image" \
3267 -d linux.bin.gz uImage
3270 The "mkimage" tool can also be used to create ramdisk images for use
3271 with U-Boot, either separated from the Linux kernel image, or
3272 combined into one file. "mkimage" encapsulates the images with a 64
3273 byte header containing information about target architecture,
3274 operating system, image type, compression method, entry points, time
3275 stamp, CRC32 checksums, etc.
3277 "mkimage" can be called in two ways: to verify existing images and
3278 print the header information, or to build new images.
3280 In the first form (with "-l" option) mkimage lists the information
3281 contained in the header of an existing U-Boot image; this includes
3282 checksum verification:
3284 tools/mkimage -l image
3285 -l ==> list image header information
3287 The second form (with "-d" option) is used to build a U-Boot image
3288 from a "data file" which is used as image payload:
3290 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3291 -n name -d data_file image
3292 -A ==> set architecture to 'arch'
3293 -O ==> set operating system to 'os'
3294 -T ==> set image type to 'type'
3295 -C ==> set compression type 'comp'
3296 -a ==> set load address to 'addr' (hex)
3297 -e ==> set entry point to 'ep' (hex)
3298 -n ==> set image name to 'name'
3299 -d ==> use image data from 'datafile'
3301 Right now, all Linux kernels for PowerPC systems use the same load
3302 address (0x00000000), but the entry point address depends on the
3305 - 2.2.x kernels have the entry point at 0x0000000C,
3306 - 2.3.x and later kernels have the entry point at 0x00000000.
3308 So a typical call to build a U-Boot image would read:
3310 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3311 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3312 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3313 > examples/uImage.TQM850L
3314 Image Name: 2.4.4 kernel for TQM850L
3315 Created: Wed Jul 19 02:34:59 2000
3316 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3317 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3318 Load Address: 0x00000000
3319 Entry Point: 0x00000000
3321 To verify the contents of the image (or check for corruption):
3323 -> tools/mkimage -l examples/uImage.TQM850L
3324 Image Name: 2.4.4 kernel for TQM850L
3325 Created: Wed Jul 19 02:34:59 2000
3326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3327 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3328 Load Address: 0x00000000
3329 Entry Point: 0x00000000
3331 NOTE: for embedded systems where boot time is critical you can trade
3332 speed for memory and install an UNCOMPRESSED image instead: this
3333 needs more space in Flash, but boots much faster since it does not
3334 need to be uncompressed:
3336 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3337 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3338 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3339 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3340 > examples/uImage.TQM850L-uncompressed
3341 Image Name: 2.4.4 kernel for TQM850L
3342 Created: Wed Jul 19 02:34:59 2000
3343 Image Type: PowerPC Linux Kernel Image (uncompressed)
3344 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3345 Load Address: 0x00000000
3346 Entry Point: 0x00000000
3349 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3350 when your kernel is intended to use an initial ramdisk:
3352 -> tools/mkimage -n 'Simple Ramdisk Image' \
3353 > -A ppc -O linux -T ramdisk -C gzip \
3354 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3355 Image Name: Simple Ramdisk Image
3356 Created: Wed Jan 12 14:01:50 2000
3357 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3358 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3359 Load Address: 0x00000000
3360 Entry Point: 0x00000000
3363 Installing a Linux Image:
3364 -------------------------
3366 To downloading a U-Boot image over the serial (console) interface,
3367 you must convert the image to S-Record format:
3369 objcopy -I binary -O srec examples/image examples/image.srec
3371 The 'objcopy' does not understand the information in the U-Boot
3372 image header, so the resulting S-Record file will be relative to
3373 address 0x00000000. To load it to a given address, you need to
3374 specify the target address as 'offset' parameter with the 'loads'
3377 Example: install the image to address 0x40100000 (which on the
3378 TQM8xxL is in the first Flash bank):
3380 => erase 40100000 401FFFFF
3386 ## Ready for S-Record download ...
3387 ~>examples/image.srec
3388 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3390 15989 15990 15991 15992
3391 [file transfer complete]
3393 ## Start Addr = 0x00000000
3396 You can check the success of the download using the 'iminfo' command;
3397 this includes a checksum verification so you can be sure no data
3398 corruption happened:
3402 ## Checking Image at 40100000 ...
3403 Image Name: 2.2.13 for initrd on TQM850L
3404 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3405 Data Size: 335725 Bytes = 327 kB = 0 MB
3406 Load Address: 00000000
3407 Entry Point: 0000000c
3408 Verifying Checksum ... OK
3414 The "bootm" command is used to boot an application that is stored in
3415 memory (RAM or Flash). In case of a Linux kernel image, the contents
3416 of the "bootargs" environment variable is passed to the kernel as
3417 parameters. You can check and modify this variable using the
3418 "printenv" and "setenv" commands:
3421 => printenv bootargs
3422 bootargs=root=/dev/ram
3424 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3426 => printenv bootargs
3427 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3430 ## Booting Linux kernel at 40020000 ...
3431 Image Name: 2.2.13 for NFS on TQM850L
3432 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3433 Data Size: 381681 Bytes = 372 kB = 0 MB
3434 Load Address: 00000000
3435 Entry Point: 0000000c
3436 Verifying Checksum ... OK
3437 Uncompressing Kernel Image ... OK
3438 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
3439 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3440 time_init: decrementer frequency = 187500000/60
3441 Calibrating delay loop... 49.77 BogoMIPS
3442 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3445 If you want to boot a Linux kernel with initial RAM disk, you pass
3446 the memory addresses of both the kernel and the initrd image (PPBCOOT
3447 format!) to the "bootm" command:
3449 => imi 40100000 40200000
3451 ## Checking Image at 40100000 ...
3452 Image Name: 2.2.13 for initrd on TQM850L
3453 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3454 Data Size: 335725 Bytes = 327 kB = 0 MB
3455 Load Address: 00000000
3456 Entry Point: 0000000c
3457 Verifying Checksum ... OK
3459 ## Checking Image at 40200000 ...
3460 Image Name: Simple Ramdisk Image
3461 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3462 Data Size: 566530 Bytes = 553 kB = 0 MB
3463 Load Address: 00000000
3464 Entry Point: 00000000
3465 Verifying Checksum ... OK
3467 => bootm 40100000 40200000
3468 ## Booting Linux kernel at 40100000 ...
3469 Image Name: 2.2.13 for initrd on TQM850L
3470 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3471 Data Size: 335725 Bytes = 327 kB = 0 MB
3472 Load Address: 00000000
3473 Entry Point: 0000000c
3474 Verifying Checksum ... OK
3475 Uncompressing Kernel Image ... OK
3476 ## Loading RAMDisk Image at 40200000 ...
3477 Image Name: Simple Ramdisk Image
3478 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3479 Data Size: 566530 Bytes = 553 kB = 0 MB
3480 Load Address: 00000000
3481 Entry Point: 00000000
3482 Verifying Checksum ... OK
3483 Loading Ramdisk ... OK
3484 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
3485 Boot arguments: root=/dev/ram
3486 time_init: decrementer frequency = 187500000/60
3487 Calibrating delay loop... 49.77 BogoMIPS
3489 RAMDISK: Compressed image found at block 0
3490 VFS: Mounted root (ext2 filesystem).
3494 Boot Linux and pass a flat device tree:
3497 First, U-Boot must be compiled with the appropriate defines. See the section
3498 titled "Linux Kernel Interface" above for a more in depth explanation. The
3499 following is an example of how to start a kernel and pass an updated
3505 oft=oftrees/mpc8540ads.dtb
3506 => tftp $oftaddr $oft
3507 Speed: 1000, full duplex
3509 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3510 Filename 'oftrees/mpc8540ads.dtb'.
3511 Load address: 0x300000
3514 Bytes transferred = 4106 (100a hex)
3515 => tftp $loadaddr $bootfile
3516 Speed: 1000, full duplex
3518 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3520 Load address: 0x200000
3521 Loading:############
3523 Bytes transferred = 1029407 (fb51f hex)
3528 => bootm $loadaddr - $oftaddr
3529 ## Booting image at 00200000 ...
3530 Image Name: Linux-2.6.17-dirty
3531 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3532 Data Size: 1029343 Bytes = 1005.2 kB
3533 Load Address: 00000000
3534 Entry Point: 00000000
3535 Verifying Checksum ... OK
3536 Uncompressing Kernel Image ... OK
3537 Booting using flat device tree at 0x300000
3538 Using MPC85xx ADS machine description
3539 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3543 More About U-Boot Image Types:
3544 ------------------------------
3546 U-Boot supports the following image types:
3548 "Standalone Programs" are directly runnable in the environment
3549 provided by U-Boot; it is expected that (if they behave
3550 well) you can continue to work in U-Boot after return from
3551 the Standalone Program.
3552 "OS Kernel Images" are usually images of some Embedded OS which
3553 will take over control completely. Usually these programs
3554 will install their own set of exception handlers, device
3555 drivers, set up the MMU, etc. - this means, that you cannot
3556 expect to re-enter U-Boot except by resetting the CPU.
3557 "RAMDisk Images" are more or less just data blocks, and their
3558 parameters (address, size) are passed to an OS kernel that is
3560 "Multi-File Images" contain several images, typically an OS
3561 (Linux) kernel image and one or more data images like
3562 RAMDisks. This construct is useful for instance when you want
3563 to boot over the network using BOOTP etc., where the boot
3564 server provides just a single image file, but you want to get
3565 for instance an OS kernel and a RAMDisk image.
3567 "Multi-File Images" start with a list of image sizes, each
3568 image size (in bytes) specified by an "uint32_t" in network
3569 byte order. This list is terminated by an "(uint32_t)0".
3570 Immediately after the terminating 0 follow the images, one by
3571 one, all aligned on "uint32_t" boundaries (size rounded up to
3572 a multiple of 4 bytes).
3574 "Firmware Images" are binary images containing firmware (like
3575 U-Boot or FPGA images) which usually will be programmed to
3578 "Script files" are command sequences that will be executed by
3579 U-Boot's command interpreter; this feature is especially
3580 useful when you configure U-Boot to use a real shell (hush)
3581 as command interpreter.
3587 One of the features of U-Boot is that you can dynamically load and
3588 run "standalone" applications, which can use some resources of
3589 U-Boot like console I/O functions or interrupt services.
3591 Two simple examples are included with the sources:
3596 'examples/hello_world.c' contains a small "Hello World" Demo
3597 application; it is automatically compiled when you build U-Boot.
3598 It's configured to run at address 0x00040004, so you can play with it
3602 ## Ready for S-Record download ...
3603 ~>examples/hello_world.srec
3604 1 2 3 4 5 6 7 8 9 10 11 ...
3605 [file transfer complete]
3607 ## Start Addr = 0x00040004
3609 => go 40004 Hello World! This is a test.
3610 ## Starting application at 0x00040004 ...
3621 Hit any key to exit ...
3623 ## Application terminated, rc = 0x0
3625 Another example, which demonstrates how to register a CPM interrupt
3626 handler with the U-Boot code, can be found in 'examples/timer.c'.
3627 Here, a CPM timer is set up to generate an interrupt every second.
3628 The interrupt service routine is trivial, just printing a '.'
3629 character, but this is just a demo program. The application can be
3630 controlled by the following keys:
3632 ? - print current values og the CPM Timer registers
3633 b - enable interrupts and start timer
3634 e - stop timer and disable interrupts
3635 q - quit application
3638 ## Ready for S-Record download ...
3639 ~>examples/timer.srec
3640 1 2 3 4 5 6 7 8 9 10 11 ...
3641 [file transfer complete]
3643 ## Start Addr = 0x00040004
3646 ## Starting application at 0x00040004 ...
3649 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3652 [q, b, e, ?] Set interval 1000000 us
3655 [q, b, e, ?] ........
3656 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3659 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3662 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3665 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3667 [q, b, e, ?] ...Stopping timer
3669 [q, b, e, ?] ## Application terminated, rc = 0x0
3675 Over time, many people have reported problems when trying to use the
3676 "minicom" terminal emulation program for serial download. I (wd)
3677 consider minicom to be broken, and recommend not to use it. Under
3678 Unix, I recommend to use C-Kermit for general purpose use (and
3679 especially for kermit binary protocol download ("loadb" command), and
3680 use "cu" for S-Record download ("loads" command).
3682 Nevertheless, if you absolutely want to use it try adding this
3683 configuration to your "File transfer protocols" section:
3685 Name Program Name U/D FullScr IO-Red. Multi
3686 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3687 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3693 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3694 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3696 Building requires a cross environment; it is known to work on
3697 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3698 need gmake since the Makefiles are not compatible with BSD make).
3699 Note that the cross-powerpc package does not install include files;
3700 attempting to build U-Boot will fail because <machine/ansi.h> is
3701 missing. This file has to be installed and patched manually:
3703 # cd /usr/pkg/cross/powerpc-netbsd/include
3705 # ln -s powerpc machine
3706 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3707 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3709 Native builds *don't* work due to incompatibilities between native
3710 and U-Boot include files.
3712 Booting assumes that (the first part of) the image booted is a
3713 stage-2 loader which in turn loads and then invokes the kernel
3714 proper. Loader sources will eventually appear in the NetBSD source
3715 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3716 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3719 Implementation Internals:
3720 =========================
3722 The following is not intended to be a complete description of every
3723 implementation detail. However, it should help to understand the
3724 inner workings of U-Boot and make it easier to port it to custom
3728 Initial Stack, Global Data:
3729 ---------------------------
3731 The implementation of U-Boot is complicated by the fact that U-Boot
3732 starts running out of ROM (flash memory), usually without access to
3733 system RAM (because the memory controller is not initialized yet).
3734 This means that we don't have writable Data or BSS segments, and BSS
3735 is not initialized as zero. To be able to get a C environment working
3736 at all, we have to allocate at least a minimal stack. Implementation
3737 options for this are defined and restricted by the CPU used: Some CPU
3738 models provide on-chip memory (like the IMMR area on MPC8xx and
3739 MPC826x processors), on others (parts of) the data cache can be
3740 locked as (mis-) used as memory, etc.
3742 Chris Hallinan posted a good summary of these issues to the
3743 U-Boot mailing list:
3745 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3746 From: "Chris Hallinan" <clh@net1plus.com>
3747 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3750 Correct me if I'm wrong, folks, but the way I understand it
3751 is this: Using DCACHE as initial RAM for Stack, etc, does not
3752 require any physical RAM backing up the cache. The cleverness
3753 is that the cache is being used as a temporary supply of
3754 necessary storage before the SDRAM controller is setup. It's
3755 beyond the scope of this list to explain the details, but you
3756 can see how this works by studying the cache architecture and
3757 operation in the architecture and processor-specific manuals.
3759 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3760 is another option for the system designer to use as an
3761 initial stack/RAM area prior to SDRAM being available. Either
3762 option should work for you. Using CS 4 should be fine if your
3763 board designers haven't used it for something that would
3764 cause you grief during the initial boot! It is frequently not
3767 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3768 with your processor/board/system design. The default value
3769 you will find in any recent u-boot distribution in
3770 walnut.h should work for you. I'd set it to a value larger
3771 than your SDRAM module. If you have a 64MB SDRAM module, set
3772 it above 400_0000. Just make sure your board has no resources
3773 that are supposed to respond to that address! That code in
3774 start.S has been around a while and should work as is when
3775 you get the config right.
3780 It is essential to remember this, since it has some impact on the C
3781 code for the initialization procedures:
3783 * Initialized global data (data segment) is read-only. Do not attempt
3786 * Do not use any uninitialized global data (or implicitely initialized
3787 as zero data - BSS segment) at all - this is undefined, initiali-
3788 zation is performed later (when relocating to RAM).
3790 * Stack space is very limited. Avoid big data buffers or things like
3793 Having only the stack as writable memory limits means we cannot use
3794 normal global data to share information beween the code. But it
3795 turned out that the implementation of U-Boot can be greatly
3796 simplified by making a global data structure (gd_t) available to all
3797 functions. We could pass a pointer to this data as argument to _all_
3798 functions, but this would bloat the code. Instead we use a feature of
3799 the GCC compiler (Global Register Variables) to share the data: we
3800 place a pointer (gd) to the global data into a register which we
3801 reserve for this purpose.
3803 When choosing a register for such a purpose we are restricted by the
3804 relevant (E)ABI specifications for the current architecture, and by
3805 GCC's implementation.
3807 For PowerPC, the following registers have specific use:
3809 R2: reserved for system use
3810 R3-R4: parameter passing and return values
3811 R5-R10: parameter passing
3812 R13: small data area pointer
3816 (U-Boot also uses R14 as internal GOT pointer.)
3818 ==> U-Boot will use R2 to hold a pointer to the global data
3820 Note: on PPC, we could use a static initializer (since the
3821 address of the global data structure is known at compile time),
3822 but it turned out that reserving a register results in somewhat
3823 smaller code - although the code savings are not that big (on
3824 average for all boards 752 bytes for the whole U-Boot image,
3825 624 text + 127 data).
3827 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3828 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3830 ==> U-Boot will use P5 to hold a pointer to the global data
3832 On ARM, the following registers are used:
3834 R0: function argument word/integer result
3835 R1-R3: function argument word
3837 R10: stack limit (used only if stack checking if enabled)
3838 R11: argument (frame) pointer
3839 R12: temporary workspace
3842 R15: program counter
3844 ==> U-Boot will use R8 to hold a pointer to the global data
3846 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3847 or current versions of GCC may "optimize" the code too much.
3852 U-Boot runs in system state and uses physical addresses, i.e. the
3853 MMU is not used either for address mapping nor for memory protection.
3855 The available memory is mapped to fixed addresses using the memory
3856 controller. In this process, a contiguous block is formed for each
3857 memory type (Flash, SDRAM, SRAM), even when it consists of several
3858 physical memory banks.
3860 U-Boot is installed in the first 128 kB of the first Flash bank (on
3861 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3862 booting and sizing and initializing DRAM, the code relocates itself
3863 to the upper end of DRAM. Immediately below the U-Boot code some
3864 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
3865 configuration setting]. Below that, a structure with global Board
3866 Info data is placed, followed by the stack (growing downward).
3868 Additionally, some exception handler code is copied to the low 8 kB
3869 of DRAM (0x00000000 ... 0x00001FFF).
3871 So a typical memory configuration with 16 MB of DRAM could look like
3874 0x0000 0000 Exception Vector code
3877 0x0000 2000 Free for Application Use
3883 0x00FB FF20 Monitor Stack (Growing downward)
3884 0x00FB FFAC Board Info Data and permanent copy of global data
3885 0x00FC 0000 Malloc Arena
3888 0x00FE 0000 RAM Copy of Monitor Code
3889 ... eventually: LCD or video framebuffer
3890 ... eventually: pRAM (Protected RAM - unchanged by reset)
3891 0x00FF FFFF [End of RAM]
3894 System Initialization:
3895 ----------------------
3897 In the reset configuration, U-Boot starts at the reset entry point
3898 (on most PowerPC systems at address 0x00000100). Because of the reset
3899 configuration for CS0# this is a mirror of the onboard Flash memory.
3900 To be able to re-map memory U-Boot then jumps to its link address.
3901 To be able to implement the initialization code in C, a (small!)
3902 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3903 which provide such a feature like MPC8xx or MPC8260), or in a locked
3904 part of the data cache. After that, U-Boot initializes the CPU core,
3905 the caches and the SIU.
3907 Next, all (potentially) available memory banks are mapped using a
3908 preliminary mapping. For example, we put them on 512 MB boundaries
3909 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3910 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3911 programmed for SDRAM access. Using the temporary configuration, a
3912 simple memory test is run that determines the size of the SDRAM
3915 When there is more than one SDRAM bank, and the banks are of
3916 different size, the largest is mapped first. For equal size, the first
3917 bank (CS2#) is mapped first. The first mapping is always for address
3918 0x00000000, with any additional banks following immediately to create
3919 contiguous memory starting from 0.
3921 Then, the monitor installs itself at the upper end of the SDRAM area
3922 and allocates memory for use by malloc() and for the global Board
3923 Info data; also, the exception vector code is copied to the low RAM
3924 pages, and the final stack is set up.
3926 Only after this relocation will you have a "normal" C environment;
3927 until that you are restricted in several ways, mostly because you are
3928 running from ROM, and because the code will have to be relocated to a
3932 U-Boot Porting Guide:
3933 ----------------------
3935 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3939 int main (int argc, char *argv[])
3941 sighandler_t no_more_time;
3943 signal (SIGALRM, no_more_time);
3944 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3946 if (available_money > available_manpower) {
3947 pay consultant to port U-Boot;
3951 Download latest U-Boot source;
3953 Subscribe to u-boot mailing list;
3956 email ("Hi, I am new to U-Boot, how do I get started?");
3960 Read the README file in the top level directory;
3961 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3962 Read the source, Luke;
3965 if (available_money > toLocalCurrency ($2500)) {
3968 Add a lot of aggravation and time;
3971 Create your own board support subdirectory;
3973 Create your own board config file;
3977 Add / modify source code;
3981 email ("Hi, I am having problems...");
3983 Send patch file to Wolfgang;
3988 void no_more_time (int sig)
3997 All contributions to U-Boot should conform to the Linux kernel
3998 coding style; see the file "Documentation/CodingStyle" and the script
3999 "scripts/Lindent" in your Linux kernel source directory. In sources
4000 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4001 spaces before parameters to function calls) is actually used.
4003 Source files originating from a different project (for example the
4004 MTD subsystem) are generally exempt from these guidelines and are not
4005 reformated to ease subsequent migration to newer versions of those
4008 Please note that U-Boot is implemented in C (and to some small parts in
4009 Assembler); no C++ is used, so please do not use C++ style comments (//)
4012 Please also stick to the following formatting rules:
4013 - remove any trailing white space
4014 - use TAB characters for indentation, not spaces
4015 - make sure NOT to use DOS '\r\n' line feeds
4016 - do not add more than 2 empty lines to source files
4017 - do not add trailing empty lines to source files
4019 Submissions which do not conform to the standards may be returned
4020 with a request to reformat the changes.
4026 Since the number of patches for U-Boot is growing, we need to
4027 establish some rules. Submissions which do not conform to these rules
4028 may be rejected, even when they contain important and valuable stuff.
4030 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4032 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4033 see http://lists.denx.de/mailman/listinfo/u-boot
4035 When you send a patch, please include the following information with
4038 * For bug fixes: a description of the bug and how your patch fixes
4039 this bug. Please try to include a way of demonstrating that the
4040 patch actually fixes something.
4042 * For new features: a description of the feature and your
4045 * A CHANGELOG entry as plaintext (separate from the patch)
4047 * For major contributions, your entry to the CREDITS file
4049 * When you add support for a new board, don't forget to add this
4050 board to the MAKEALL script, too.
4052 * If your patch adds new configuration options, don't forget to
4053 document these in the README file.
4055 * The patch itself. If you are using git (which is *strongly*
4056 recommended) you can easily generate the patch using the
4057 "git-format-patch". If you then use "git-send-email" to send it to
4058 the U-Boot mailing list, you will avoid most of the common problems
4059 with some other mail clients.
4061 If you cannot use git, use "diff -purN OLD NEW". If your version of
4062 diff does not support these options, then get the latest version of
4065 The current directory when running this command shall be the parent
4066 directory of the U-Boot source tree (i. e. please make sure that
4067 your patch includes sufficient directory information for the
4070 We prefer patches as plain text. MIME attachments are discouraged,
4071 and compressed attachments must not be used.
4073 * If one logical set of modifications affects or creates several
4074 files, all these changes shall be submitted in a SINGLE patch file.
4076 * Changesets that contain different, unrelated modifications shall be
4077 submitted as SEPARATE patches, one patch per changeset.
4082 * Before sending the patch, run the MAKEALL script on your patched
4083 source tree and make sure that no errors or warnings are reported
4084 for any of the boards.
4086 * Keep your modifications to the necessary minimum: A patch
4087 containing several unrelated changes or arbitrary reformats will be
4088 returned with a request to re-formatting / split it.
4090 * If you modify existing code, make sure that your new code does not
4091 add to the memory footprint of the code ;-) Small is beautiful!
4092 When adding new features, these should compile conditionally only
4093 (using #ifdef), and the resulting code with the new feature
4094 disabled must not need more memory than the old code without your
4097 * Remember that there is a size limit of 100 kB per message on the
4098 u-boot mailing list. Bigger patches will be moderated. If they are
4099 reasonable and not too big, they will be acknowledged. But patches
4100 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob