2 # (C) Copyright 2000 - 2011
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 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /x86 Files generic to x86 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /mips32 Files specific to MIPS32 CPUs
184 /xburst Files specific to Ingenic XBurst CPUs
185 /lib Architecture specific library files
186 /nds32 Files generic to NDS32 architecture
187 /cpu CPU specific files
188 /n1213 Files specific to Andes Technology N1213 CPUs
189 /lib Architecture specific library files
190 /nios2 Files generic to Altera NIOS2 architecture
191 /cpu CPU specific files
192 /lib Architecture specific library files
193 /powerpc Files generic to PowerPC architecture
194 /cpu CPU specific files
195 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
196 /mpc5xx Files specific to Freescale MPC5xx CPUs
197 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
198 /mpc8xx Files specific to Freescale MPC8xx CPUs
199 /mpc8220 Files specific to Freescale MPC8220 CPUs
200 /mpc824x Files specific to Freescale MPC824x CPUs
201 /mpc8260 Files specific to Freescale MPC8260 CPUs
202 /mpc85xx Files specific to Freescale MPC85xx CPUs
203 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
204 /lib Architecture specific library files
205 /sh Files generic to SH architecture
206 /cpu CPU specific files
207 /sh2 Files specific to sh2 CPUs
208 /sh3 Files specific to sh3 CPUs
209 /sh4 Files specific to sh4 CPUs
210 /lib Architecture specific library files
211 /sparc Files generic to SPARC architecture
212 /cpu CPU specific files
213 /leon2 Files specific to Gaisler LEON2 SPARC CPU
214 /leon3 Files specific to Gaisler LEON3 SPARC CPU
215 /lib Architecture specific library files
216 /api Machine/arch independent API for external apps
217 /board Board dependent files
218 /common Misc architecture independent functions
219 /disk Code for disk drive partition handling
220 /doc Documentation (don't expect too much)
221 /drivers Commonly used device drivers
222 /examples Example code for standalone applications, etc.
223 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
224 /include Header Files
225 /lib Files generic to all architectures
226 /libfdt Library files to support flattened device trees
227 /lzma Library files to support LZMA decompression
228 /lzo Library files to support LZO decompression
230 /post Power On Self Test
231 /rtc Real Time Clock drivers
232 /tools Tools to build S-Record or U-Boot images, etc.
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the CPU type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
294 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
296 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
297 Define exactly one, e.g. CONFIG_ATSTK1002
299 - CPU Module Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
302 --- FIXME --- not tested yet:
303 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
304 CONFIG_CMA287_23, CONFIG_CMA287_50
306 - Motherboard Type: (if CONFIG_COGENT is defined)
307 Define exactly one of
308 CONFIG_CMA101, CONFIG_CMA102
310 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
311 Define one or more of
314 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
315 Define one or more of
316 CONFIG_LCD_HEARTBEAT - update a character position on
317 the LCD display every second with
320 - Board flavour: (if CONFIG_MPC8260ADS is defined)
323 CONFIG_SYS_8260ADS - original MPC8260ADS
324 CONFIG_SYS_8266ADS - MPC8266ADS
325 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
326 CONFIG_SYS_8272ADS - MPC8272ADS
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - MPC824X Family Member (if CONFIG_MPC824X is defined)
334 Define exactly one of
335 CONFIG_MPC8240, CONFIG_MPC8245
337 - 8xx CPU Options: (if using an MPC8xx CPU)
338 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
339 get_gclk_freq() cannot work
340 e.g. if there is no 32KHz
341 reference PIT/RTC clock
342 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
345 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
346 CONFIG_SYS_8xx_CPUCLK_MIN
347 CONFIG_SYS_8xx_CPUCLK_MAX
348 CONFIG_8xx_CPUCLK_DEFAULT
349 See doc/README.MPC866
351 CONFIG_SYS_MEASURE_CPUCLK
353 Define this to measure the actual CPU clock instead
354 of relying on the correctness of the configured
355 values. Mostly useful for board bringup to make sure
356 the PLL is locked at the intended frequency. Note
357 that this requires a (stable) reference clock (32 kHz
358 RTC clock or CONFIG_SYS_8XX_XIN)
360 CONFIG_SYS_DELAYED_ICACHE
362 Define this option if you want to enable the
363 ICache only when Code runs from RAM.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 - Intel Monahans options:
378 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
380 Defines the Monahans run mode to oscillator
381 ratio. Valid values are 8, 16, 24, 31. The core
382 frequency is this value multiplied by 13 MHz.
384 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
386 Defines the Monahans turbo mode to oscillator
387 ratio. Valid values are 1 (default if undefined) and
388 2. The core frequency as calculated above is multiplied
392 CONFIG_SYS_INIT_SP_OFFSET
394 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
395 pointer. This is needed for the temporary stack before
398 CONFIG_SYS_MIPS_CACHE_MODE
400 Cache operation mode for the MIPS CPU.
401 See also arch/mips/include/asm/mipsregs.h.
403 CONF_CM_CACHABLE_NO_WA
406 CONF_CM_CACHABLE_NONCOHERENT
410 CONF_CM_CACHABLE_ACCELERATED
412 CONFIG_SYS_XWAY_EBU_BOOTCFG
414 Special option for Lantiq XWAY SoCs for booting from NOR flash.
415 See also arch/mips/cpu/mips32/start.S.
417 CONFIG_XWAY_SWAP_BYTES
419 Enable compilation of tools/xway-swap-bytes needed for Lantiq
420 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
421 be swapped if a flash programmer is used.
423 - Linux Kernel Interface:
426 U-Boot stores all clock information in Hz
427 internally. For binary compatibility with older Linux
428 kernels (which expect the clocks passed in the
429 bd_info data to be in MHz) the environment variable
430 "clocks_in_mhz" can be defined so that U-Boot
431 converts clock data to MHZ before passing it to the
433 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
434 "clocks_in_mhz=1" is automatically included in the
437 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
439 When transferring memsize parameter to linux, some versions
440 expect it to be in bytes, others in MB.
441 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
445 New kernel versions are expecting firmware settings to be
446 passed using flattened device trees (based on open firmware
450 * New libfdt-based support
451 * Adds the "fdt" command
452 * The bootm command automatically updates the fdt
454 OF_CPU - The proper name of the cpus node (only required for
455 MPC512X and MPC5xxx based boards).
456 OF_SOC - The proper name of the soc node (only required for
457 MPC512X and MPC5xxx based boards).
458 OF_TBCLK - The timebase frequency.
459 OF_STDOUT_PATH - The path to the console device
461 boards with QUICC Engines require OF_QE to set UCC MAC
464 CONFIG_OF_BOARD_SETUP
466 Board code has addition modification that it wants to make
467 to the flat device tree before handing it off to the kernel
471 This define fills in the correct boot CPU in the boot
472 param header, the default value is zero if undefined.
476 U-Boot can detect if an IDE device is present or not.
477 If not, and this new config option is activated, U-Boot
478 removes the ATA node from the DTS before booting Linux,
479 so the Linux IDE driver does not probe the device and
480 crash. This is needed for buggy hardware (uc101) where
481 no pull down resistor is connected to the signal IDE5V_DD7.
483 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
485 This setting is mandatory for all boards that have only one
486 machine type and must be used to specify the machine type
487 number as it appears in the ARM machine registry
488 (see http://www.arm.linux.org.uk/developer/machines/).
489 Only boards that have multiple machine types supported
490 in a single configuration file and the machine type is
491 runtime discoverable, do not have to use this setting.
493 - vxWorks boot parameters:
495 bootvx constructs a valid bootline using the following
496 environments variables: bootfile, ipaddr, serverip, hostname.
497 It loads the vxWorks image pointed bootfile.
499 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
500 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
501 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
502 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
504 CONFIG_SYS_VXWORKS_ADD_PARAMS
506 Add it at the end of the bootline. E.g "u=username pw=secret"
508 Note: If a "bootargs" environment is defined, it will overwride
509 the defaults discussed just above.
511 - Cache Configuration:
512 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
513 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
514 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
516 - Cache Configuration for ARM:
517 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
519 CONFIG_SYS_PL310_BASE - Physical base address of PL310
520 controller register space
525 Define this if you want support for Amba PrimeCell PL010 UARTs.
529 Define this if you want support for Amba PrimeCell PL011 UARTs.
533 If you have Amba PrimeCell PL011 UARTs, set this variable to
534 the clock speed of the UARTs.
538 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
539 define this to a list of base addresses for each (supported)
540 port. See e.g. include/configs/versatile.h
542 CONFIG_PL011_SERIAL_RLCR
544 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
545 have separate receive and transmit line control registers. Set
546 this variable to initialize the extra register.
548 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
550 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
551 boot loader that has already initialized the UART. Define this
552 variable to flush the UART at init time.
556 Depending on board, define exactly one serial port
557 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
558 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
559 console by defining CONFIG_8xx_CONS_NONE
561 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
562 port routines must be defined elsewhere
563 (i.e. serial_init(), serial_getc(), ...)
566 Enables console device for a color framebuffer. Needs following
567 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
568 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
570 VIDEO_HW_RECTFILL graphic chip supports
573 VIDEO_HW_BITBLT graphic chip supports
574 bit-blit (cf. smiLynxEM)
575 VIDEO_VISIBLE_COLS visible pixel columns
577 VIDEO_VISIBLE_ROWS visible pixel rows
578 VIDEO_PIXEL_SIZE bytes per pixel
579 VIDEO_DATA_FORMAT graphic data format
580 (0-5, cf. cfb_console.c)
581 VIDEO_FB_ADRS framebuffer address
582 VIDEO_KBD_INIT_FCT keyboard int fct
583 (i.e. i8042_kbd_init())
584 VIDEO_TSTC_FCT test char fct
586 VIDEO_GETC_FCT get char fct
588 CONFIG_CONSOLE_CURSOR cursor drawing on/off
589 (requires blink timer
591 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
592 CONFIG_CONSOLE_TIME display time/date info in
594 (requires CONFIG_CMD_DATE)
595 CONFIG_VIDEO_LOGO display Linux logo in
597 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
598 linux_logo.h for logo.
599 Requires CONFIG_VIDEO_LOGO
600 CONFIG_CONSOLE_EXTRA_INFO
601 additional board info beside
604 When CONFIG_CFB_CONSOLE is defined, video console is
605 default i/o. Serial console can be forced with
606 environment 'console=serial'.
608 When CONFIG_SILENT_CONSOLE is defined, all console
609 messages (by U-Boot and Linux!) can be silenced with
610 the "silent" environment variable. See
611 doc/README.silent for more information.
614 CONFIG_BAUDRATE - in bps
615 Select one of the baudrates listed in
616 CONFIG_SYS_BAUDRATE_TABLE, see below.
617 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
619 - Console Rx buffer length
620 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
621 the maximum receive buffer length for the SMC.
622 This option is actual only for 82xx and 8xx possible.
623 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
624 must be defined, to setup the maximum idle timeout for
627 - Pre-Console Buffer:
628 Prior to the console being initialised (i.e. serial UART
629 initialised etc) all console output is silently discarded.
630 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
631 buffer any console messages prior to the console being
632 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
633 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
634 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
635 bytes are output before the console is initialised, the
636 earlier bytes are discarded.
638 'Sane' compilers will generate smaller code if
639 CONFIG_PRE_CON_BUF_SZ is a power of 2
641 - Boot Delay: CONFIG_BOOTDELAY - in seconds
642 Delay before automatically booting the default image;
643 set to -1 to disable autoboot.
645 See doc/README.autoboot for these options that
646 work with CONFIG_BOOTDELAY. None are required.
647 CONFIG_BOOT_RETRY_TIME
648 CONFIG_BOOT_RETRY_MIN
649 CONFIG_AUTOBOOT_KEYED
650 CONFIG_AUTOBOOT_PROMPT
651 CONFIG_AUTOBOOT_DELAY_STR
652 CONFIG_AUTOBOOT_STOP_STR
653 CONFIG_AUTOBOOT_DELAY_STR2
654 CONFIG_AUTOBOOT_STOP_STR2
655 CONFIG_ZERO_BOOTDELAY_CHECK
656 CONFIG_RESET_TO_RETRY
660 Only needed when CONFIG_BOOTDELAY is enabled;
661 define a command string that is automatically executed
662 when no character is read on the console interface
663 within "Boot Delay" after reset.
666 This can be used to pass arguments to the bootm
667 command. The value of CONFIG_BOOTARGS goes into the
668 environment value "bootargs".
670 CONFIG_RAMBOOT and CONFIG_NFSBOOT
671 The value of these goes into the environment as
672 "ramboot" and "nfsboot" respectively, and can be used
673 as a convenience, when switching between booting from
679 When this option is #defined, the existence of the
680 environment variable "preboot" will be checked
681 immediately before starting the CONFIG_BOOTDELAY
682 countdown and/or running the auto-boot command resp.
683 entering interactive mode.
685 This feature is especially useful when "preboot" is
686 automatically generated or modified. For an example
687 see the LWMON board specific code: here "preboot" is
688 modified when the user holds down a certain
689 combination of keys on the (special) keyboard when
692 - Serial Download Echo Mode:
694 If defined to 1, all characters received during a
695 serial download (using the "loads" command) are
696 echoed back. This might be needed by some terminal
697 emulations (like "cu"), but may as well just take
698 time on others. This setting #define's the initial
699 value of the "loads_echo" environment variable.
701 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
703 Select one of the baudrates listed in
704 CONFIG_SYS_BAUDRATE_TABLE, see below.
707 Monitor commands can be included or excluded
708 from the build by using the #include files
709 "config_cmd_all.h" and #undef'ing unwanted
710 commands, or using "config_cmd_default.h"
711 and augmenting with additional #define's
714 The default command configuration includes all commands
715 except those marked below with a "*".
717 CONFIG_CMD_ASKENV * ask for env variable
718 CONFIG_CMD_BDI bdinfo
719 CONFIG_CMD_BEDBUG * Include BedBug Debugger
720 CONFIG_CMD_BMP * BMP support
721 CONFIG_CMD_BSP * Board specific commands
722 CONFIG_CMD_BOOTD bootd
723 CONFIG_CMD_CACHE * icache, dcache
724 CONFIG_CMD_CONSOLE coninfo
725 CONFIG_CMD_CRC32 * crc32
726 CONFIG_CMD_DATE * support for RTC, date/time...
727 CONFIG_CMD_DHCP * DHCP support
728 CONFIG_CMD_DIAG * Diagnostics
729 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
730 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
731 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
732 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
733 CONFIG_CMD_DTT * Digital Therm and Thermostat
734 CONFIG_CMD_ECHO echo arguments
735 CONFIG_CMD_EDITENV edit env variable
736 CONFIG_CMD_EEPROM * EEPROM read/write support
737 CONFIG_CMD_ELF * bootelf, bootvx
738 CONFIG_CMD_EXPORTENV * export the environment
739 CONFIG_CMD_SAVEENV saveenv
740 CONFIG_CMD_FDC * Floppy Disk Support
741 CONFIG_CMD_FAT * FAT partition support
742 CONFIG_CMD_FDOS * Dos diskette Support
743 CONFIG_CMD_FLASH flinfo, erase, protect
744 CONFIG_CMD_FPGA FPGA device initialization support
745 CONFIG_CMD_GO * the 'go' command (exec code)
746 CONFIG_CMD_GREPENV * search environment
747 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
748 CONFIG_CMD_I2C * I2C serial bus support
749 CONFIG_CMD_IDE * IDE harddisk support
750 CONFIG_CMD_IMI iminfo
751 CONFIG_CMD_IMLS List all found images
752 CONFIG_CMD_IMMAP * IMMR dump support
753 CONFIG_CMD_IMPORTENV * import an environment
754 CONFIG_CMD_IRQ * irqinfo
755 CONFIG_CMD_ITEST Integer/string test of 2 values
756 CONFIG_CMD_JFFS2 * JFFS2 Support
757 CONFIG_CMD_KGDB * kgdb
758 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
759 CONFIG_CMD_LOADB loadb
760 CONFIG_CMD_LOADS loads
761 CONFIG_CMD_MD5SUM print md5 message digest
762 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
763 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
765 CONFIG_CMD_MISC Misc functions like sleep etc
766 CONFIG_CMD_MMC * MMC memory mapped support
767 CONFIG_CMD_MII * MII utility commands
768 CONFIG_CMD_MTDPARTS * MTD partition support
769 CONFIG_CMD_NAND * NAND support
770 CONFIG_CMD_NET bootp, tftpboot, rarpboot
771 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
772 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
773 CONFIG_CMD_PCI * pciinfo
774 CONFIG_CMD_PCMCIA * PCMCIA support
775 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
777 CONFIG_CMD_PORTIO * Port I/O
778 CONFIG_CMD_REGINFO * Register dump
779 CONFIG_CMD_RUN run command in env variable
780 CONFIG_CMD_SAVES * save S record dump
781 CONFIG_CMD_SCSI * SCSI Support
782 CONFIG_CMD_SDRAM * print SDRAM configuration information
783 (requires CONFIG_CMD_I2C)
784 CONFIG_CMD_SETGETDCR Support for DCR Register access
786 CONFIG_CMD_SHA1SUM print sha1 memory digest
787 (requires CONFIG_CMD_MEMORY)
788 CONFIG_CMD_SOURCE "source" command Support
789 CONFIG_CMD_SPI * SPI serial bus support
790 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
791 CONFIG_CMD_TIME * run command and report execution time
792 CONFIG_CMD_USB * USB support
793 CONFIG_CMD_CDP * Cisco Discover Protocol support
794 CONFIG_CMD_FSL * Microblaze FSL support
797 EXAMPLE: If you want all functions except of network
798 support you can write:
800 #include "config_cmd_all.h"
801 #undef CONFIG_CMD_NET
804 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
806 Note: Don't enable the "icache" and "dcache" commands
807 (configuration option CONFIG_CMD_CACHE) unless you know
808 what you (and your U-Boot users) are doing. Data
809 cache cannot be enabled on systems like the 8xx or
810 8260 (where accesses to the IMMR region must be
811 uncached), and it cannot be disabled on all other
812 systems where we (mis-) use the data cache to hold an
813 initial stack and some data.
816 XXX - this list needs to get updated!
820 If this variable is defined, it enables watchdog
821 support for the SoC. There must be support in the SoC
822 specific code for a watchdog. For the 8xx and 8260
823 CPUs, the SIU Watchdog feature is enabled in the SYPCR
824 register. When supported for a specific SoC is
825 available, then no further board specific code should
829 When using a watchdog circuitry external to the used
830 SoC, then define this variable and provide board
831 specific code for the "hw_watchdog_reset" function.
834 CONFIG_VERSION_VARIABLE
835 If this variable is defined, an environment variable
836 named "ver" is created by U-Boot showing the U-Boot
837 version as printed by the "version" command.
838 This variable is readonly.
842 When CONFIG_CMD_DATE is selected, the type of the RTC
843 has to be selected, too. Define exactly one of the
846 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
847 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
848 CONFIG_RTC_MC13783 - use MC13783 RTC
849 CONFIG_RTC_MC146818 - use MC146818 RTC
850 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
851 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
852 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
853 CONFIG_RTC_DS164x - use Dallas DS164x RTC
854 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
855 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
856 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
857 CONFIG_SYS_RV3029_TCR - enable trickle charger on
860 Note that if the RTC uses I2C, then the I2C interface
861 must also be configured. See I2C Support, below.
864 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
865 CONFIG_PCA953X_INFO - enable pca953x info command
867 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
868 chip-ngpio pairs that tell the PCA953X driver the number of
869 pins supported by a particular chip.
871 Note that if the GPIO device uses I2C, then the I2C interface
872 must also be configured. See I2C Support, below.
876 When CONFIG_TIMESTAMP is selected, the timestamp
877 (date and time) of an image is printed by image
878 commands like bootm or iminfo. This option is
879 automatically enabled when you select CONFIG_CMD_DATE .
882 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
883 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
885 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
886 CONFIG_CMD_SCSI) you must configure support for at
887 least one partition type as well.
890 CONFIG_IDE_RESET_ROUTINE - this is defined in several
891 board configurations files but used nowhere!
893 CONFIG_IDE_RESET - is this is defined, IDE Reset will
894 be performed by calling the function
895 ide_set_reset(int reset)
896 which has to be defined in a board specific file
901 Set this to enable ATAPI support.
906 Set this to enable support for disks larger than 137GB
907 Also look at CONFIG_SYS_64BIT_LBA.
908 Whithout these , LBA48 support uses 32bit variables and will 'only'
909 support disks up to 2.1TB.
911 CONFIG_SYS_64BIT_LBA:
912 When enabled, makes the IDE subsystem use 64bit sector addresses.
916 At the moment only there is only support for the
917 SYM53C8XX SCSI controller; define
918 CONFIG_SCSI_SYM53C8XX to enable it.
920 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
921 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
922 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
923 maximum numbers of LUNs, SCSI ID's and target
925 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
927 - NETWORK Support (PCI):
929 Support for Intel 8254x gigabit chips.
931 CONFIG_E1000_FALLBACK_MAC
932 default MAC for empty EEPROM after production.
935 Support for Intel 82557/82559/82559ER chips.
936 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
937 write routine for first time initialisation.
940 Support for Digital 2114x chips.
941 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
942 modem chip initialisation (KS8761/QS6611).
945 Support for National dp83815 chips.
948 Support for National dp8382[01] gigabit chips.
950 - NETWORK Support (other):
952 CONFIG_DRIVER_AT91EMAC
953 Support for AT91RM9200 EMAC.
956 Define this to use reduced MII inteface
958 CONFIG_DRIVER_AT91EMAC_QUIET
959 If this defined, the driver is quiet.
960 The driver doen't show link status messages.
962 CONFIG_DRIVER_LAN91C96
963 Support for SMSC's LAN91C96 chips.
966 Define this to hold the physical address
967 of the LAN91C96's I/O space
969 CONFIG_LAN91C96_USE_32_BIT
970 Define this to enable 32 bit addressing
972 CONFIG_DRIVER_SMC91111
973 Support for SMSC's LAN91C111 chip
976 Define this to hold the physical address
977 of the device (I/O space)
979 CONFIG_SMC_USE_32_BIT
980 Define this if data bus is 32 bits
982 CONFIG_SMC_USE_IOFUNCS
983 Define this to use i/o functions instead of macros
984 (some hardware wont work with macros)
987 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
989 CONFIG_FTGMAC100_EGIGA
990 Define this to use GE link update with gigabit PHY.
991 Define this if FTGMAC100 is connected to gigabit PHY.
992 If your system has 10/100 PHY only, it might not occur
993 wrong behavior. Because PHY usually return timeout or
994 useless data when polling gigabit status and gigabit
995 control registers. This behavior won't affect the
996 correctnessof 10/100 link speed update.
999 Support for SMSC's LAN911x and LAN921x chips
1002 Define this to hold the physical address
1003 of the device (I/O space)
1005 CONFIG_SMC911X_32_BIT
1006 Define this if data bus is 32 bits
1008 CONFIG_SMC911X_16_BIT
1009 Define this if data bus is 16 bits. If your processor
1010 automatically converts one 32 bit word to two 16 bit
1011 words you may also try CONFIG_SMC911X_32_BIT.
1014 Support for Renesas on-chip Ethernet controller
1016 CONFIG_SH_ETHER_USE_PORT
1017 Define the number of ports to be used
1019 CONFIG_SH_ETHER_PHY_ADDR
1020 Define the ETH PHY's address
1022 CONFIG_SH_ETHER_CACHE_WRITEBACK
1023 If this option is set, the driver enables cache flush.
1026 At the moment only the UHCI host controller is
1027 supported (PIP405, MIP405, MPC5200); define
1028 CONFIG_USB_UHCI to enable it.
1029 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1030 and define CONFIG_USB_STORAGE to enable the USB
1033 Supported are USB Keyboards and USB Floppy drives
1035 MPC5200 USB requires additional defines:
1037 for 528 MHz Clock: 0x0001bbbb
1041 for differential drivers: 0x00001000
1042 for single ended drivers: 0x00005000
1043 for differential drivers on PSC3: 0x00000100
1044 for single ended drivers on PSC3: 0x00004100
1045 CONFIG_SYS_USB_EVENT_POLL
1046 May be defined to allow interrupt polling
1047 instead of using asynchronous interrupts
1050 Define the below if you wish to use the USB console.
1051 Once firmware is rebuilt from a serial console issue the
1052 command "setenv stdin usbtty; setenv stdout usbtty" and
1053 attach your USB cable. The Unix command "dmesg" should print
1054 it has found a new device. The environment variable usbtty
1055 can be set to gserial or cdc_acm to enable your device to
1056 appear to a USB host as a Linux gserial device or a
1057 Common Device Class Abstract Control Model serial device.
1058 If you select usbtty = gserial you should be able to enumerate
1060 # modprobe usbserial vendor=0xVendorID product=0xProductID
1061 else if using cdc_acm, simply setting the environment
1062 variable usbtty to be cdc_acm should suffice. The following
1063 might be defined in YourBoardName.h
1066 Define this to build a UDC device
1069 Define this to have a tty type of device available to
1070 talk to the UDC device
1072 CONFIG_SYS_CONSOLE_IS_IN_ENV
1073 Define this if you want stdin, stdout &/or stderr to
1077 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1078 Derive USB clock from external clock "blah"
1079 - CONFIG_SYS_USB_EXTC_CLK 0x02
1081 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1082 Derive USB clock from brgclk
1083 - CONFIG_SYS_USB_BRG_CLK 0x04
1085 If you have a USB-IF assigned VendorID then you may wish to
1086 define your own vendor specific values either in BoardName.h
1087 or directly in usbd_vendor_info.h. If you don't define
1088 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1089 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1090 should pretend to be a Linux device to it's target host.
1092 CONFIG_USBD_MANUFACTURER
1093 Define this string as the name of your company for
1094 - CONFIG_USBD_MANUFACTURER "my company"
1096 CONFIG_USBD_PRODUCT_NAME
1097 Define this string as the name of your product
1098 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1100 CONFIG_USBD_VENDORID
1101 Define this as your assigned Vendor ID from the USB
1102 Implementors Forum. This *must* be a genuine Vendor ID
1103 to avoid polluting the USB namespace.
1104 - CONFIG_USBD_VENDORID 0xFFFF
1106 CONFIG_USBD_PRODUCTID
1107 Define this as the unique Product ID
1109 - CONFIG_USBD_PRODUCTID 0xFFFF
1113 The MMC controller on the Intel PXA is supported. To
1114 enable this define CONFIG_MMC. The MMC can be
1115 accessed from the boot prompt by mapping the device
1116 to physical memory similar to flash. Command line is
1117 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1118 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1121 Support for Renesas on-chip MMCIF controller
1123 CONFIG_SH_MMCIF_ADDR
1124 Define the base address of MMCIF registers
1127 Define the clock frequency for MMCIF
1129 - Journaling Flash filesystem support:
1130 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1131 CONFIG_JFFS2_NAND_DEV
1132 Define these for a default partition on a NAND device
1134 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1135 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1136 Define these for a default partition on a NOR device
1138 CONFIG_SYS_JFFS_CUSTOM_PART
1139 Define this to create an own partition. You have to provide a
1140 function struct part_info* jffs2_part_info(int part_num)
1142 If you define only one JFFS2 partition you may also want to
1143 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1144 to disable the command chpart. This is the default when you
1145 have not defined a custom partition
1150 Define this to enable standard (PC-Style) keyboard
1154 Standard PC keyboard driver with US (is default) and
1155 GERMAN key layout (switch via environment 'keymap=de') support.
1156 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1157 for cfb_console. Supports cursor blinking.
1162 Define this to enable video support (for output to
1165 CONFIG_VIDEO_CT69000
1167 Enable Chips & Technologies 69000 Video chip
1169 CONFIG_VIDEO_SMI_LYNXEM
1170 Enable Silicon Motion SMI 712/710/810 Video chip. The
1171 video output is selected via environment 'videoout'
1172 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1175 For the CT69000 and SMI_LYNXEM drivers, videomode is
1176 selected via environment 'videomode'. Two different ways
1178 - "videomode=num" 'num' is a standard LiLo mode numbers.
1179 Following standard modes are supported (* is default):
1181 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1182 -------------+---------------------------------------------
1183 8 bits | 0x301* 0x303 0x305 0x161 0x307
1184 15 bits | 0x310 0x313 0x316 0x162 0x319
1185 16 bits | 0x311 0x314 0x317 0x163 0x31A
1186 24 bits | 0x312 0x315 0x318 ? 0x31B
1187 -------------+---------------------------------------------
1188 (i.e. setenv videomode 317; saveenv; reset;)
1190 - "videomode=bootargs" all the video parameters are parsed
1191 from the bootargs. (See drivers/video/videomodes.c)
1194 CONFIG_VIDEO_SED13806
1195 Enable Epson SED13806 driver. This driver supports 8bpp
1196 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1197 or CONFIG_VIDEO_SED13806_16BPP
1200 Enable the Freescale DIU video driver. Reference boards for
1201 SOCs that have a DIU should define this macro to enable DIU
1202 support, and should also define these other macros:
1208 CONFIG_VIDEO_SW_CURSOR
1209 CONFIG_VGA_AS_SINGLE_DEVICE
1211 CONFIG_VIDEO_BMP_LOGO
1213 The DIU driver will look for the 'video-mode' environment
1214 variable, and if defined, enable the DIU as a console during
1215 boot. See the documentation file README.video for a
1216 description of this variable.
1221 Define this to enable a custom keyboard support.
1222 This simply calls drv_keyboard_init() which must be
1223 defined in your board-specific files.
1224 The only board using this so far is RBC823.
1226 - LCD Support: CONFIG_LCD
1228 Define this to enable LCD support (for output to LCD
1229 display); also select one of the supported displays
1230 by defining one of these:
1234 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1236 CONFIG_NEC_NL6448AC33:
1238 NEC NL6448AC33-18. Active, color, single scan.
1240 CONFIG_NEC_NL6448BC20
1242 NEC NL6448BC20-08. 6.5", 640x480.
1243 Active, color, single scan.
1245 CONFIG_NEC_NL6448BC33_54
1247 NEC NL6448BC33-54. 10.4", 640x480.
1248 Active, color, single scan.
1252 Sharp 320x240. Active, color, single scan.
1253 It isn't 16x9, and I am not sure what it is.
1255 CONFIG_SHARP_LQ64D341
1257 Sharp LQ64D341 display, 640x480.
1258 Active, color, single scan.
1262 HLD1045 display, 640x480.
1263 Active, color, single scan.
1267 Optrex CBL50840-2 NF-FW 99 22 M5
1269 Hitachi LMG6912RPFC-00T
1273 320x240. Black & white.
1275 Normally display is black on white background; define
1276 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1278 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1280 If this option is set, the environment is checked for
1281 a variable "splashimage". If found, the usual display
1282 of logo, copyright and system information on the LCD
1283 is suppressed and the BMP image at the address
1284 specified in "splashimage" is loaded instead. The
1285 console is redirected to the "nulldev", too. This
1286 allows for a "silent" boot where a splash screen is
1287 loaded very quickly after power-on.
1289 CONFIG_SPLASH_SCREEN_ALIGN
1291 If this option is set the splash image can be freely positioned
1292 on the screen. Environment variable "splashpos" specifies the
1293 position as "x,y". If a positive number is given it is used as
1294 number of pixel from left/top. If a negative number is given it
1295 is used as number of pixel from right/bottom. You can also
1296 specify 'm' for centering the image.
1299 setenv splashpos m,m
1300 => image at center of screen
1302 setenv splashpos 30,20
1303 => image at x = 30 and y = 20
1305 setenv splashpos -10,m
1306 => vertically centered image
1307 at x = dspWidth - bmpWidth - 9
1309 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1311 If this option is set, additionally to standard BMP
1312 images, gzipped BMP images can be displayed via the
1313 splashscreen support or the bmp command.
1315 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1317 If this option is set, 8-bit RLE compressed BMP images
1318 can be displayed via the splashscreen support or the
1321 - Compression support:
1324 If this option is set, support for bzip2 compressed
1325 images is included. If not, only uncompressed and gzip
1326 compressed images are supported.
1328 NOTE: the bzip2 algorithm requires a lot of RAM, so
1329 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1334 If this option is set, support for lzma compressed
1337 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1338 requires an amount of dynamic memory that is given by the
1341 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1343 Where lc and lp stand for, respectively, Literal context bits
1344 and Literal pos bits.
1346 This value is upper-bounded by 14MB in the worst case. Anyway,
1347 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1348 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1349 a very small buffer.
1351 Use the lzmainfo tool to determinate the lc and lp values and
1352 then calculate the amount of needed dynamic memory (ensuring
1353 the appropriate CONFIG_SYS_MALLOC_LEN value).
1358 The address of PHY on MII bus.
1360 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1362 The clock frequency of the MII bus
1366 If this option is set, support for speed/duplex
1367 detection of gigabit PHY is included.
1369 CONFIG_PHY_RESET_DELAY
1371 Some PHY like Intel LXT971A need extra delay after
1372 reset before any MII register access is possible.
1373 For such PHY, set this option to the usec delay
1374 required. (minimum 300usec for LXT971A)
1376 CONFIG_PHY_CMD_DELAY (ppc4xx)
1378 Some PHY like Intel LXT971A need extra delay after
1379 command issued before MII status register can be read
1389 Define a default value for Ethernet address to use
1390 for the respective Ethernet interface, in case this
1391 is not determined automatically.
1396 Define a default value for the IP address to use for
1397 the default Ethernet interface, in case this is not
1398 determined through e.g. bootp.
1400 - Server IP address:
1403 Defines a default value for the IP address of a TFTP
1404 server to contact when using the "tftboot" command.
1406 CONFIG_KEEP_SERVERADDR
1408 Keeps the server's MAC address, in the env 'serveraddr'
1409 for passing to bootargs (like Linux's netconsole option)
1411 - Multicast TFTP Mode:
1414 Defines whether you want to support multicast TFTP as per
1415 rfc-2090; for example to work with atftp. Lets lots of targets
1416 tftp down the same boot image concurrently. Note: the Ethernet
1417 driver in use must provide a function: mcast() to join/leave a
1420 - BOOTP Recovery Mode:
1421 CONFIG_BOOTP_RANDOM_DELAY
1423 If you have many targets in a network that try to
1424 boot using BOOTP, you may want to avoid that all
1425 systems send out BOOTP requests at precisely the same
1426 moment (which would happen for instance at recovery
1427 from a power failure, when all systems will try to
1428 boot, thus flooding the BOOTP server. Defining
1429 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1430 inserted before sending out BOOTP requests. The
1431 following delays are inserted then:
1433 1st BOOTP request: delay 0 ... 1 sec
1434 2nd BOOTP request: delay 0 ... 2 sec
1435 3rd BOOTP request: delay 0 ... 4 sec
1437 BOOTP requests: delay 0 ... 8 sec
1439 - DHCP Advanced Options:
1440 You can fine tune the DHCP functionality by defining
1441 CONFIG_BOOTP_* symbols:
1443 CONFIG_BOOTP_SUBNETMASK
1444 CONFIG_BOOTP_GATEWAY
1445 CONFIG_BOOTP_HOSTNAME
1446 CONFIG_BOOTP_NISDOMAIN
1447 CONFIG_BOOTP_BOOTPATH
1448 CONFIG_BOOTP_BOOTFILESIZE
1451 CONFIG_BOOTP_SEND_HOSTNAME
1452 CONFIG_BOOTP_NTPSERVER
1453 CONFIG_BOOTP_TIMEOFFSET
1454 CONFIG_BOOTP_VENDOREX
1456 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1457 environment variable, not the BOOTP server.
1459 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1460 serverip from a DHCP server, it is possible that more
1461 than one DNS serverip is offered to the client.
1462 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1463 serverip will be stored in the additional environment
1464 variable "dnsip2". The first DNS serverip is always
1465 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1468 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1469 to do a dynamic update of a DNS server. To do this, they
1470 need the hostname of the DHCP requester.
1471 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1472 of the "hostname" environment variable is passed as
1473 option 12 to the DHCP server.
1475 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1477 A 32bit value in microseconds for a delay between
1478 receiving a "DHCP Offer" and sending the "DHCP Request".
1479 This fixes a problem with certain DHCP servers that don't
1480 respond 100% of the time to a "DHCP request". E.g. On an
1481 AT91RM9200 processor running at 180MHz, this delay needed
1482 to be *at least* 15,000 usec before a Windows Server 2003
1483 DHCP server would reply 100% of the time. I recommend at
1484 least 50,000 usec to be safe. The alternative is to hope
1485 that one of the retries will be successful but note that
1486 the DHCP timeout and retry process takes a longer than
1490 CONFIG_CDP_DEVICE_ID
1492 The device id used in CDP trigger frames.
1494 CONFIG_CDP_DEVICE_ID_PREFIX
1496 A two character string which is prefixed to the MAC address
1501 A printf format string which contains the ascii name of
1502 the port. Normally is set to "eth%d" which sets
1503 eth0 for the first Ethernet, eth1 for the second etc.
1505 CONFIG_CDP_CAPABILITIES
1507 A 32bit integer which indicates the device capabilities;
1508 0x00000010 for a normal host which does not forwards.
1512 An ascii string containing the version of the software.
1516 An ascii string containing the name of the platform.
1520 A 32bit integer sent on the trigger.
1522 CONFIG_CDP_POWER_CONSUMPTION
1524 A 16bit integer containing the power consumption of the
1525 device in .1 of milliwatts.
1527 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1529 A byte containing the id of the VLAN.
1531 - Status LED: CONFIG_STATUS_LED
1533 Several configurations allow to display the current
1534 status using a LED. For instance, the LED will blink
1535 fast while running U-Boot code, stop blinking as
1536 soon as a reply to a BOOTP request was received, and
1537 start blinking slow once the Linux kernel is running
1538 (supported by a status LED driver in the Linux
1539 kernel). Defining CONFIG_STATUS_LED enables this
1542 - CAN Support: CONFIG_CAN_DRIVER
1544 Defining CONFIG_CAN_DRIVER enables CAN driver support
1545 on those systems that support this (optional)
1546 feature, like the TQM8xxL modules.
1548 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1550 These enable I2C serial bus commands. Defining either of
1551 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1552 include the appropriate I2C driver for the selected CPU.
1554 This will allow you to use i2c commands at the u-boot
1555 command line (as long as you set CONFIG_CMD_I2C in
1556 CONFIG_COMMANDS) and communicate with i2c based realtime
1557 clock chips. See common/cmd_i2c.c for a description of the
1558 command line interface.
1560 CONFIG_HARD_I2C selects a hardware I2C controller.
1562 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1563 bit-banging) driver instead of CPM or similar hardware
1566 There are several other quantities that must also be
1567 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1569 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1570 to be the frequency (in Hz) at which you wish your i2c bus
1571 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1572 the CPU's i2c node address).
1574 Now, the u-boot i2c code for the mpc8xx
1575 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1576 and so its address should therefore be cleared to 0 (See,
1577 eg, MPC823e User's Manual p.16-473). So, set
1578 CONFIG_SYS_I2C_SLAVE to 0.
1580 CONFIG_SYS_I2C_INIT_MPC5XXX
1582 When a board is reset during an i2c bus transfer
1583 chips might think that the current transfer is still
1584 in progress. Reset the slave devices by sending start
1585 commands until the slave device responds.
1587 That's all that's required for CONFIG_HARD_I2C.
1589 If you use the software i2c interface (CONFIG_SOFT_I2C)
1590 then the following macros need to be defined (examples are
1591 from include/configs/lwmon.h):
1595 (Optional). Any commands necessary to enable the I2C
1596 controller or configure ports.
1598 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1602 (Only for MPC8260 CPU). The I/O port to use (the code
1603 assumes both bits are on the same port). Valid values
1604 are 0..3 for ports A..D.
1608 The code necessary to make the I2C data line active
1609 (driven). If the data line is open collector, this
1612 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1616 The code necessary to make the I2C data line tri-stated
1617 (inactive). If the data line is open collector, this
1620 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1624 Code that returns TRUE if the I2C data line is high,
1627 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1631 If <bit> is TRUE, sets the I2C data line high. If it
1632 is FALSE, it clears it (low).
1634 eg: #define I2C_SDA(bit) \
1635 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1636 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1640 If <bit> is TRUE, sets the I2C clock line high. If it
1641 is FALSE, it clears it (low).
1643 eg: #define I2C_SCL(bit) \
1644 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1645 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1649 This delay is invoked four times per clock cycle so this
1650 controls the rate of data transfer. The data rate thus
1651 is 1 / (I2C_DELAY * 4). Often defined to be something
1654 #define I2C_DELAY udelay(2)
1656 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1658 If your arch supports the generic GPIO framework (asm/gpio.h),
1659 then you may alternatively define the two GPIOs that are to be
1660 used as SCL / SDA. Any of the previous I2C_xxx macros will
1661 have GPIO-based defaults assigned to them as appropriate.
1663 You should define these to the GPIO value as given directly to
1664 the generic GPIO functions.
1666 CONFIG_SYS_I2C_INIT_BOARD
1668 When a board is reset during an i2c bus transfer
1669 chips might think that the current transfer is still
1670 in progress. On some boards it is possible to access
1671 the i2c SCLK line directly, either by using the
1672 processor pin as a GPIO or by having a second pin
1673 connected to the bus. If this option is defined a
1674 custom i2c_init_board() routine in boards/xxx/board.c
1675 is run early in the boot sequence.
1677 CONFIG_SYS_I2C_BOARD_LATE_INIT
1679 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1680 defined a custom i2c_board_late_init() routine in
1681 boards/xxx/board.c is run AFTER the operations in i2c_init()
1682 is completed. This callpoint can be used to unreset i2c bus
1683 using CPU i2c controller register accesses for CPUs whose i2c
1684 controller provide such a method. It is called at the end of
1685 i2c_init() to allow i2c_init operations to setup the i2c bus
1686 controller on the CPU (e.g. setting bus speed & slave address).
1688 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1690 This option enables configuration of bi_iic_fast[] flags
1691 in u-boot bd_info structure based on u-boot environment
1692 variable "i2cfast". (see also i2cfast)
1694 CONFIG_I2C_MULTI_BUS
1696 This option allows the use of multiple I2C buses, each of which
1697 must have a controller. At any point in time, only one bus is
1698 active. To switch to a different bus, use the 'i2c dev' command.
1699 Note that bus numbering is zero-based.
1701 CONFIG_SYS_I2C_NOPROBES
1703 This option specifies a list of I2C devices that will be skipped
1704 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1705 is set, specify a list of bus-device pairs. Otherwise, specify
1706 a 1D array of device addresses
1709 #undef CONFIG_I2C_MULTI_BUS
1710 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1712 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1714 #define CONFIG_I2C_MULTI_BUS
1715 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1717 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1719 CONFIG_SYS_SPD_BUS_NUM
1721 If defined, then this indicates the I2C bus number for DDR SPD.
1722 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1724 CONFIG_SYS_RTC_BUS_NUM
1726 If defined, then this indicates the I2C bus number for the RTC.
1727 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1729 CONFIG_SYS_DTT_BUS_NUM
1731 If defined, then this indicates the I2C bus number for the DTT.
1732 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1734 CONFIG_SYS_I2C_DTT_ADDR:
1736 If defined, specifies the I2C address of the DTT device.
1737 If not defined, then U-Boot uses predefined value for
1738 specified DTT device.
1742 Define this option if you want to use Freescale's I2C driver in
1743 drivers/i2c/fsl_i2c.c.
1747 Define this option if you have I2C devices reached over 1 .. n
1748 I2C Muxes like the pca9544a. This option addes a new I2C
1749 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1750 new I2C Bus to the existing I2C Busses. If you select the
1751 new Bus with "i2c dev", u-bbot sends first the commandos for
1752 the muxes to activate this new "bus".
1754 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1758 Adding a new I2C Bus reached over 2 pca9544a muxes
1759 The First mux with address 70 and channel 6
1760 The Second mux with address 71 and channel 4
1762 => i2c bus pca9544a:70:6:pca9544a:71:4
1764 Use the "i2c bus" command without parameter, to get a list
1765 of I2C Busses with muxes:
1768 Busses reached over muxes:
1770 reached over Mux(es):
1773 reached over Mux(es):
1778 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1779 u-boot first sends the command to the mux@70 to enable
1780 channel 6, and then the command to the mux@71 to enable
1783 After that, you can use the "normal" i2c commands as
1784 usual to communicate with your I2C devices behind
1787 This option is actually implemented for the bitbanging
1788 algorithm in common/soft_i2c.c and for the Hardware I2C
1789 Bus on the MPC8260. But it should be not so difficult
1790 to add this option to other architectures.
1792 CONFIG_SOFT_I2C_READ_REPEATED_START
1794 defining this will force the i2c_read() function in
1795 the soft_i2c driver to perform an I2C repeated start
1796 between writing the address pointer and reading the
1797 data. If this define is omitted the default behaviour
1798 of doing a stop-start sequence will be used. Most I2C
1799 devices can use either method, but some require one or
1802 - SPI Support: CONFIG_SPI
1804 Enables SPI driver (so far only tested with
1805 SPI EEPROM, also an instance works with Crystal A/D and
1806 D/As on the SACSng board)
1810 Enables the driver for SPI controller on SuperH. Currently
1811 only SH7757 is supported.
1815 Enables extended (16-bit) SPI EEPROM addressing.
1816 (symmetrical to CONFIG_I2C_X)
1820 Enables a software (bit-bang) SPI driver rather than
1821 using hardware support. This is a general purpose
1822 driver that only requires three general I/O port pins
1823 (two outputs, one input) to function. If this is
1824 defined, the board configuration must define several
1825 SPI configuration items (port pins to use, etc). For
1826 an example, see include/configs/sacsng.h.
1830 Enables a hardware SPI driver for general-purpose reads
1831 and writes. As with CONFIG_SOFT_SPI, the board configuration
1832 must define a list of chip-select function pointers.
1833 Currently supported on some MPC8xxx processors. For an
1834 example, see include/configs/mpc8349emds.h.
1838 Enables the driver for the SPI controllers on i.MX and MXC
1839 SoCs. Currently only i.MX31 is supported.
1841 - FPGA Support: CONFIG_FPGA
1843 Enables FPGA subsystem.
1845 CONFIG_FPGA_<vendor>
1847 Enables support for specific chip vendors.
1850 CONFIG_FPGA_<family>
1852 Enables support for FPGA family.
1853 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1857 Specify the number of FPGA devices to support.
1859 CONFIG_SYS_FPGA_PROG_FEEDBACK
1861 Enable printing of hash marks during FPGA configuration.
1863 CONFIG_SYS_FPGA_CHECK_BUSY
1865 Enable checks on FPGA configuration interface busy
1866 status by the configuration function. This option
1867 will require a board or device specific function to
1872 If defined, a function that provides delays in the FPGA
1873 configuration driver.
1875 CONFIG_SYS_FPGA_CHECK_CTRLC
1876 Allow Control-C to interrupt FPGA configuration
1878 CONFIG_SYS_FPGA_CHECK_ERROR
1880 Check for configuration errors during FPGA bitfile
1881 loading. For example, abort during Virtex II
1882 configuration if the INIT_B line goes low (which
1883 indicated a CRC error).
1885 CONFIG_SYS_FPGA_WAIT_INIT
1887 Maximum time to wait for the INIT_B line to deassert
1888 after PROB_B has been deasserted during a Virtex II
1889 FPGA configuration sequence. The default time is 500
1892 CONFIG_SYS_FPGA_WAIT_BUSY
1894 Maximum time to wait for BUSY to deassert during
1895 Virtex II FPGA configuration. The default is 5 ms.
1897 CONFIG_SYS_FPGA_WAIT_CONFIG
1899 Time to wait after FPGA configuration. The default is
1902 - Configuration Management:
1905 If defined, this string will be added to the U-Boot
1906 version information (U_BOOT_VERSION)
1908 - Vendor Parameter Protection:
1910 U-Boot considers the values of the environment
1911 variables "serial#" (Board Serial Number) and
1912 "ethaddr" (Ethernet Address) to be parameters that
1913 are set once by the board vendor / manufacturer, and
1914 protects these variables from casual modification by
1915 the user. Once set, these variables are read-only,
1916 and write or delete attempts are rejected. You can
1917 change this behaviour:
1919 If CONFIG_ENV_OVERWRITE is #defined in your config
1920 file, the write protection for vendor parameters is
1921 completely disabled. Anybody can change or delete
1924 Alternatively, if you #define _both_ CONFIG_ETHADDR
1925 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1926 Ethernet address is installed in the environment,
1927 which can be changed exactly ONCE by the user. [The
1928 serial# is unaffected by this, i. e. it remains
1934 Define this variable to enable the reservation of
1935 "protected RAM", i. e. RAM which is not overwritten
1936 by U-Boot. Define CONFIG_PRAM to hold the number of
1937 kB you want to reserve for pRAM. You can overwrite
1938 this default value by defining an environment
1939 variable "pram" to the number of kB you want to
1940 reserve. Note that the board info structure will
1941 still show the full amount of RAM. If pRAM is
1942 reserved, a new environment variable "mem" will
1943 automatically be defined to hold the amount of
1944 remaining RAM in a form that can be passed as boot
1945 argument to Linux, for instance like that:
1947 setenv bootargs ... mem=\${mem}
1950 This way you can tell Linux not to use this memory,
1951 either, which results in a memory region that will
1952 not be affected by reboots.
1954 *WARNING* If your board configuration uses automatic
1955 detection of the RAM size, you must make sure that
1956 this memory test is non-destructive. So far, the
1957 following board configurations are known to be
1960 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1961 HERMES, IP860, RPXlite, LWMON, LANTEC,
1967 Define this variable to stop the system in case of a
1968 fatal error, so that you have to reset it manually.
1969 This is probably NOT a good idea for an embedded
1970 system where you want the system to reboot
1971 automatically as fast as possible, but it may be
1972 useful during development since you can try to debug
1973 the conditions that lead to the situation.
1975 CONFIG_NET_RETRY_COUNT
1977 This variable defines the number of retries for
1978 network operations like ARP, RARP, TFTP, or BOOTP
1979 before giving up the operation. If not defined, a
1980 default value of 5 is used.
1984 Timeout waiting for an ARP reply in milliseconds.
1986 - Command Interpreter:
1987 CONFIG_AUTO_COMPLETE
1989 Enable auto completion of commands using TAB.
1991 Note that this feature has NOT been implemented yet
1992 for the "hush" shell.
1995 CONFIG_SYS_HUSH_PARSER
1997 Define this variable to enable the "hush" shell (from
1998 Busybox) as command line interpreter, thus enabling
1999 powerful command line syntax like
2000 if...then...else...fi conditionals or `&&' and '||'
2001 constructs ("shell scripts").
2003 If undefined, you get the old, much simpler behaviour
2004 with a somewhat smaller memory footprint.
2007 CONFIG_SYS_PROMPT_HUSH_PS2
2009 This defines the secondary prompt string, which is
2010 printed when the command interpreter needs more input
2011 to complete a command. Usually "> ".
2015 In the current implementation, the local variables
2016 space and global environment variables space are
2017 separated. Local variables are those you define by
2018 simply typing `name=value'. To access a local
2019 variable later on, you have write `$name' or
2020 `${name}'; to execute the contents of a variable
2021 directly type `$name' at the command prompt.
2023 Global environment variables are those you use
2024 setenv/printenv to work with. To run a command stored
2025 in such a variable, you need to use the run command,
2026 and you must not use the '$' sign to access them.
2028 To store commands and special characters in a
2029 variable, please use double quotation marks
2030 surrounding the whole text of the variable, instead
2031 of the backslashes before semicolons and special
2034 - Commandline Editing and History:
2035 CONFIG_CMDLINE_EDITING
2037 Enable editing and History functions for interactive
2038 commandline input operations
2040 - Default Environment:
2041 CONFIG_EXTRA_ENV_SETTINGS
2043 Define this to contain any number of null terminated
2044 strings (variable = value pairs) that will be part of
2045 the default environment compiled into the boot image.
2047 For example, place something like this in your
2048 board's config file:
2050 #define CONFIG_EXTRA_ENV_SETTINGS \
2054 Warning: This method is based on knowledge about the
2055 internal format how the environment is stored by the
2056 U-Boot code. This is NOT an official, exported
2057 interface! Although it is unlikely that this format
2058 will change soon, there is no guarantee either.
2059 You better know what you are doing here.
2061 Note: overly (ab)use of the default environment is
2062 discouraged. Make sure to check other ways to preset
2063 the environment like the "source" command or the
2066 - DataFlash Support:
2067 CONFIG_HAS_DATAFLASH
2069 Defining this option enables DataFlash features and
2070 allows to read/write in Dataflash via the standard
2073 - SystemACE Support:
2076 Adding this option adds support for Xilinx SystemACE
2077 chips attached via some sort of local bus. The address
2078 of the chip must also be defined in the
2079 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2081 #define CONFIG_SYSTEMACE
2082 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2084 When SystemACE support is added, the "ace" device type
2085 becomes available to the fat commands, i.e. fatls.
2087 - TFTP Fixed UDP Port:
2090 If this is defined, the environment variable tftpsrcp
2091 is used to supply the TFTP UDP source port value.
2092 If tftpsrcp isn't defined, the normal pseudo-random port
2093 number generator is used.
2095 Also, the environment variable tftpdstp is used to supply
2096 the TFTP UDP destination port value. If tftpdstp isn't
2097 defined, the normal port 69 is used.
2099 The purpose for tftpsrcp is to allow a TFTP server to
2100 blindly start the TFTP transfer using the pre-configured
2101 target IP address and UDP port. This has the effect of
2102 "punching through" the (Windows XP) firewall, allowing
2103 the remainder of the TFTP transfer to proceed normally.
2104 A better solution is to properly configure the firewall,
2105 but sometimes that is not allowed.
2107 - Show boot progress:
2108 CONFIG_SHOW_BOOT_PROGRESS
2110 Defining this option allows to add some board-
2111 specific code (calling a user-provided function
2112 "show_boot_progress(int)") that enables you to show
2113 the system's boot progress on some display (for
2114 example, some LED's) on your board. At the moment,
2115 the following checkpoints are implemented:
2117 Legacy uImage format:
2120 1 common/cmd_bootm.c before attempting to boot an image
2121 -1 common/cmd_bootm.c Image header has bad magic number
2122 2 common/cmd_bootm.c Image header has correct magic number
2123 -2 common/cmd_bootm.c Image header has bad checksum
2124 3 common/cmd_bootm.c Image header has correct checksum
2125 -3 common/cmd_bootm.c Image data has bad checksum
2126 4 common/cmd_bootm.c Image data has correct checksum
2127 -4 common/cmd_bootm.c Image is for unsupported architecture
2128 5 common/cmd_bootm.c Architecture check OK
2129 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2130 6 common/cmd_bootm.c Image Type check OK
2131 -6 common/cmd_bootm.c gunzip uncompression error
2132 -7 common/cmd_bootm.c Unimplemented compression type
2133 7 common/cmd_bootm.c Uncompression OK
2134 8 common/cmd_bootm.c No uncompress/copy overwrite error
2135 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2137 9 common/image.c Start initial ramdisk verification
2138 -10 common/image.c Ramdisk header has bad magic number
2139 -11 common/image.c Ramdisk header has bad checksum
2140 10 common/image.c Ramdisk header is OK
2141 -12 common/image.c Ramdisk data has bad checksum
2142 11 common/image.c Ramdisk data has correct checksum
2143 12 common/image.c Ramdisk verification complete, start loading
2144 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2145 13 common/image.c Start multifile image verification
2146 14 common/image.c No initial ramdisk, no multifile, continue.
2148 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2150 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2151 -31 post/post.c POST test failed, detected by post_output_backlog()
2152 -32 post/post.c POST test failed, detected by post_run_single()
2154 34 common/cmd_doc.c before loading a Image from a DOC device
2155 -35 common/cmd_doc.c Bad usage of "doc" command
2156 35 common/cmd_doc.c correct usage of "doc" command
2157 -36 common/cmd_doc.c No boot device
2158 36 common/cmd_doc.c correct boot device
2159 -37 common/cmd_doc.c Unknown Chip ID on boot device
2160 37 common/cmd_doc.c correct chip ID found, device available
2161 -38 common/cmd_doc.c Read Error on boot device
2162 38 common/cmd_doc.c reading Image header from DOC device OK
2163 -39 common/cmd_doc.c Image header has bad magic number
2164 39 common/cmd_doc.c Image header has correct magic number
2165 -40 common/cmd_doc.c Error reading Image from DOC device
2166 40 common/cmd_doc.c Image header has correct magic number
2167 41 common/cmd_ide.c before loading a Image from a IDE device
2168 -42 common/cmd_ide.c Bad usage of "ide" command
2169 42 common/cmd_ide.c correct usage of "ide" command
2170 -43 common/cmd_ide.c No boot device
2171 43 common/cmd_ide.c boot device found
2172 -44 common/cmd_ide.c Device not available
2173 44 common/cmd_ide.c Device available
2174 -45 common/cmd_ide.c wrong partition selected
2175 45 common/cmd_ide.c partition selected
2176 -46 common/cmd_ide.c Unknown partition table
2177 46 common/cmd_ide.c valid partition table found
2178 -47 common/cmd_ide.c Invalid partition type
2179 47 common/cmd_ide.c correct partition type
2180 -48 common/cmd_ide.c Error reading Image Header on boot device
2181 48 common/cmd_ide.c reading Image Header from IDE device OK
2182 -49 common/cmd_ide.c Image header has bad magic number
2183 49 common/cmd_ide.c Image header has correct magic number
2184 -50 common/cmd_ide.c Image header has bad checksum
2185 50 common/cmd_ide.c Image header has correct checksum
2186 -51 common/cmd_ide.c Error reading Image from IDE device
2187 51 common/cmd_ide.c reading Image from IDE device OK
2188 52 common/cmd_nand.c before loading a Image from a NAND device
2189 -53 common/cmd_nand.c Bad usage of "nand" command
2190 53 common/cmd_nand.c correct usage of "nand" command
2191 -54 common/cmd_nand.c No boot device
2192 54 common/cmd_nand.c boot device found
2193 -55 common/cmd_nand.c Unknown Chip ID on boot device
2194 55 common/cmd_nand.c correct chip ID found, device available
2195 -56 common/cmd_nand.c Error reading Image Header on boot device
2196 56 common/cmd_nand.c reading Image Header from NAND device OK
2197 -57 common/cmd_nand.c Image header has bad magic number
2198 57 common/cmd_nand.c Image header has correct magic number
2199 -58 common/cmd_nand.c Error reading Image from NAND device
2200 58 common/cmd_nand.c reading Image from NAND device OK
2202 -60 common/env_common.c Environment has a bad CRC, using default
2204 64 net/eth.c starting with Ethernet configuration.
2205 -64 net/eth.c no Ethernet found.
2206 65 net/eth.c Ethernet found.
2208 -80 common/cmd_net.c usage wrong
2209 80 common/cmd_net.c before calling NetLoop()
2210 -81 common/cmd_net.c some error in NetLoop() occurred
2211 81 common/cmd_net.c NetLoop() back without error
2212 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2213 82 common/cmd_net.c trying automatic boot
2214 83 common/cmd_net.c running "source" command
2215 -83 common/cmd_net.c some error in automatic boot or "source" command
2216 84 common/cmd_net.c end without errors
2221 100 common/cmd_bootm.c Kernel FIT Image has correct format
2222 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2223 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2224 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2225 102 common/cmd_bootm.c Kernel unit name specified
2226 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2227 103 common/cmd_bootm.c Found configuration node
2228 104 common/cmd_bootm.c Got kernel subimage node offset
2229 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2230 105 common/cmd_bootm.c Kernel subimage hash verification OK
2231 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2232 106 common/cmd_bootm.c Architecture check OK
2233 -106 common/cmd_bootm.c Kernel subimage has wrong type
2234 107 common/cmd_bootm.c Kernel subimage type OK
2235 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2236 108 common/cmd_bootm.c Got kernel subimage data/size
2237 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2238 -109 common/cmd_bootm.c Can't get kernel subimage type
2239 -110 common/cmd_bootm.c Can't get kernel subimage comp
2240 -111 common/cmd_bootm.c Can't get kernel subimage os
2241 -112 common/cmd_bootm.c Can't get kernel subimage load address
2242 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2244 120 common/image.c Start initial ramdisk verification
2245 -120 common/image.c Ramdisk FIT image has incorrect format
2246 121 common/image.c Ramdisk FIT image has correct format
2247 122 common/image.c No ramdisk subimage unit name, using configuration
2248 -122 common/image.c Can't get configuration for ramdisk subimage
2249 123 common/image.c Ramdisk unit name specified
2250 -124 common/image.c Can't get ramdisk subimage node offset
2251 125 common/image.c Got ramdisk subimage node offset
2252 -125 common/image.c Ramdisk subimage hash verification failed
2253 126 common/image.c Ramdisk subimage hash verification OK
2254 -126 common/image.c Ramdisk subimage for unsupported architecture
2255 127 common/image.c Architecture check OK
2256 -127 common/image.c Can't get ramdisk subimage data/size
2257 128 common/image.c Got ramdisk subimage data/size
2258 129 common/image.c Can't get ramdisk load address
2259 -129 common/image.c Got ramdisk load address
2261 -130 common/cmd_doc.c Incorrect FIT image format
2262 131 common/cmd_doc.c FIT image format OK
2264 -140 common/cmd_ide.c Incorrect FIT image format
2265 141 common/cmd_ide.c FIT image format OK
2267 -150 common/cmd_nand.c Incorrect FIT image format
2268 151 common/cmd_nand.c FIT image format OK
2270 - Standalone program support:
2271 CONFIG_STANDALONE_LOAD_ADDR
2273 This option defines a board specific value for the
2274 address where standalone program gets loaded, thus
2275 overwriting the architecture dependent default
2278 - Frame Buffer Address:
2281 Define CONFIG_FB_ADDR if you want to use specific
2282 address for frame buffer.
2283 Then system will reserve the frame buffer address to
2284 defined address instead of lcd_setmem (this function
2285 grabs the memory for frame buffer by panel's size).
2287 Please see board_init_f function.
2289 - Automatic software updates via TFTP server
2291 CONFIG_UPDATE_TFTP_CNT_MAX
2292 CONFIG_UPDATE_TFTP_MSEC_MAX
2294 These options enable and control the auto-update feature;
2295 for a more detailed description refer to doc/README.update.
2297 - MTD Support (mtdparts command, UBI support)
2300 Adds the MTD device infrastructure from the Linux kernel.
2301 Needed for mtdparts command support.
2303 CONFIG_MTD_PARTITIONS
2305 Adds the MTD partitioning infrastructure from the Linux
2306 kernel. Needed for UBI support.
2310 Enable building of SPL globally.
2312 CONFIG_SPL_TEXT_BASE
2313 TEXT_BASE for linking the SPL binary.
2316 LDSCRIPT for linking the SPL binary.
2318 CONFIG_SPL_LIBCOMMON_SUPPORT
2319 Support for common/libcommon.o in SPL binary
2321 CONFIG_SPL_LIBDISK_SUPPORT
2322 Support for disk/libdisk.o in SPL binary
2324 CONFIG_SPL_I2C_SUPPORT
2325 Support for drivers/i2c/libi2c.o in SPL binary
2327 CONFIG_SPL_GPIO_SUPPORT
2328 Support for drivers/gpio/libgpio.o in SPL binary
2330 CONFIG_SPL_MMC_SUPPORT
2331 Support for drivers/mmc/libmmc.o in SPL binary
2333 CONFIG_SPL_SERIAL_SUPPORT
2334 Support for drivers/serial/libserial.o in SPL binary
2336 CONFIG_SPL_SPI_FLASH_SUPPORT
2337 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2339 CONFIG_SPL_SPI_SUPPORT
2340 Support for drivers/spi/libspi.o in SPL binary
2342 CONFIG_SPL_FAT_SUPPORT
2343 Support for fs/fat/libfat.o in SPL binary
2345 CONFIG_SPL_LIBGENERIC_SUPPORT
2346 Support for lib/libgeneric.o in SPL binary
2351 [so far only for SMDK2400 boards]
2353 - Modem support enable:
2354 CONFIG_MODEM_SUPPORT
2356 - RTS/CTS Flow control enable:
2359 - Modem debug support:
2360 CONFIG_MODEM_SUPPORT_DEBUG
2362 Enables debugging stuff (char screen[1024], dbg())
2363 for modem support. Useful only with BDI2000.
2365 - Interrupt support (PPC):
2367 There are common interrupt_init() and timer_interrupt()
2368 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2369 for CPU specific initialization. interrupt_init_cpu()
2370 should set decrementer_count to appropriate value. If
2371 CPU resets decrementer automatically after interrupt
2372 (ppc4xx) it should set decrementer_count to zero.
2373 timer_interrupt() calls timer_interrupt_cpu() for CPU
2374 specific handling. If board has watchdog / status_led
2375 / other_activity_monitor it works automatically from
2376 general timer_interrupt().
2380 In the target system modem support is enabled when a
2381 specific key (key combination) is pressed during
2382 power-on. Otherwise U-Boot will boot normally
2383 (autoboot). The key_pressed() function is called from
2384 board_init(). Currently key_pressed() is a dummy
2385 function, returning 1 and thus enabling modem
2388 If there are no modem init strings in the
2389 environment, U-Boot proceed to autoboot; the
2390 previous output (banner, info printfs) will be
2393 See also: doc/README.Modem
2396 Configuration Settings:
2397 -----------------------
2399 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2400 undefine this when you're short of memory.
2402 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2403 width of the commands listed in the 'help' command output.
2405 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2406 prompt for user input.
2408 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2410 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2412 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2414 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2415 the application (usually a Linux kernel) when it is
2418 - CONFIG_SYS_BAUDRATE_TABLE:
2419 List of legal baudrate settings for this board.
2421 - CONFIG_SYS_CONSOLE_INFO_QUIET
2422 Suppress display of console information at boot.
2424 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2425 If the board specific function
2426 extern int overwrite_console (void);
2427 returns 1, the stdin, stderr and stdout are switched to the
2428 serial port, else the settings in the environment are used.
2430 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2431 Enable the call to overwrite_console().
2433 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2434 Enable overwrite of previous console environment settings.
2436 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2437 Begin and End addresses of the area used by the
2440 - CONFIG_SYS_ALT_MEMTEST:
2441 Enable an alternate, more extensive memory test.
2443 - CONFIG_SYS_MEMTEST_SCRATCH:
2444 Scratch address used by the alternate memory test
2445 You only need to set this if address zero isn't writeable
2447 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2448 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2449 this specified memory area will get subtracted from the top
2450 (end) of RAM and won't get "touched" at all by U-Boot. By
2451 fixing up gd->ram_size the Linux kernel should gets passed
2452 the now "corrected" memory size and won't touch it either.
2453 This should work for arch/ppc and arch/powerpc. Only Linux
2454 board ports in arch/powerpc with bootwrapper support that
2455 recalculate the memory size from the SDRAM controller setup
2456 will have to get fixed in Linux additionally.
2458 This option can be used as a workaround for the 440EPx/GRx
2459 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2462 WARNING: Please make sure that this value is a multiple of
2463 the Linux page size (normally 4k). If this is not the case,
2464 then the end address of the Linux memory will be located at a
2465 non page size aligned address and this could cause major
2468 - CONFIG_SYS_TFTP_LOADADDR:
2469 Default load address for network file downloads
2471 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2472 Enable temporary baudrate change while serial download
2474 - CONFIG_SYS_SDRAM_BASE:
2475 Physical start address of SDRAM. _Must_ be 0 here.
2477 - CONFIG_SYS_MBIO_BASE:
2478 Physical start address of Motherboard I/O (if using a
2481 - CONFIG_SYS_FLASH_BASE:
2482 Physical start address of Flash memory.
2484 - CONFIG_SYS_MONITOR_BASE:
2485 Physical start address of boot monitor code (set by
2486 make config files to be same as the text base address
2487 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2488 CONFIG_SYS_FLASH_BASE when booting from flash.
2490 - CONFIG_SYS_MONITOR_LEN:
2491 Size of memory reserved for monitor code, used to
2492 determine _at_compile_time_ (!) if the environment is
2493 embedded within the U-Boot image, or in a separate
2496 - CONFIG_SYS_MALLOC_LEN:
2497 Size of DRAM reserved for malloc() use.
2499 - CONFIG_SYS_BOOTM_LEN:
2500 Normally compressed uImages are limited to an
2501 uncompressed size of 8 MBytes. If this is not enough,
2502 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2503 to adjust this setting to your needs.
2505 - CONFIG_SYS_BOOTMAPSZ:
2506 Maximum size of memory mapped by the startup code of
2507 the Linux kernel; all data that must be processed by
2508 the Linux kernel (bd_info, boot arguments, FDT blob if
2509 used) must be put below this limit, unless "bootm_low"
2510 enviroment variable is defined and non-zero. In such case
2511 all data for the Linux kernel must be between "bootm_low"
2512 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2513 variable "bootm_mapsize" will override the value of
2514 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2515 then the value in "bootm_size" will be used instead.
2517 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2518 Enable initrd_high functionality. If defined then the
2519 initrd_high feature is enabled and the bootm ramdisk subcommand
2522 - CONFIG_SYS_BOOT_GET_CMDLINE:
2523 Enables allocating and saving kernel cmdline in space between
2524 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2526 - CONFIG_SYS_BOOT_GET_KBD:
2527 Enables allocating and saving a kernel copy of the bd_info in
2528 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2530 - CONFIG_SYS_MAX_FLASH_BANKS:
2531 Max number of Flash memory banks
2533 - CONFIG_SYS_MAX_FLASH_SECT:
2534 Max number of sectors on a Flash chip
2536 - CONFIG_SYS_FLASH_ERASE_TOUT:
2537 Timeout for Flash erase operations (in ms)
2539 - CONFIG_SYS_FLASH_WRITE_TOUT:
2540 Timeout for Flash write operations (in ms)
2542 - CONFIG_SYS_FLASH_LOCK_TOUT
2543 Timeout for Flash set sector lock bit operation (in ms)
2545 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2546 Timeout for Flash clear lock bits operation (in ms)
2548 - CONFIG_SYS_FLASH_PROTECTION
2549 If defined, hardware flash sectors protection is used
2550 instead of U-Boot software protection.
2552 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2554 Enable TFTP transfers directly to flash memory;
2555 without this option such a download has to be
2556 performed in two steps: (1) download to RAM, and (2)
2557 copy from RAM to flash.
2559 The two-step approach is usually more reliable, since
2560 you can check if the download worked before you erase
2561 the flash, but in some situations (when system RAM is
2562 too limited to allow for a temporary copy of the
2563 downloaded image) this option may be very useful.
2565 - CONFIG_SYS_FLASH_CFI:
2566 Define if the flash driver uses extra elements in the
2567 common flash structure for storing flash geometry.
2569 - CONFIG_FLASH_CFI_DRIVER
2570 This option also enables the building of the cfi_flash driver
2571 in the drivers directory
2573 - CONFIG_FLASH_CFI_MTD
2574 This option enables the building of the cfi_mtd driver
2575 in the drivers directory. The driver exports CFI flash
2578 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2579 Use buffered writes to flash.
2581 - CONFIG_FLASH_SPANSION_S29WS_N
2582 s29ws-n MirrorBit flash has non-standard addresses for buffered
2585 - CONFIG_SYS_FLASH_QUIET_TEST
2586 If this option is defined, the common CFI flash doesn't
2587 print it's warning upon not recognized FLASH banks. This
2588 is useful, if some of the configured banks are only
2589 optionally available.
2591 - CONFIG_FLASH_SHOW_PROGRESS
2592 If defined (must be an integer), print out countdown
2593 digits and dots. Recommended value: 45 (9..1) for 80
2594 column displays, 15 (3..1) for 40 column displays.
2596 - CONFIG_SYS_RX_ETH_BUFFER:
2597 Defines the number of Ethernet receive buffers. On some
2598 Ethernet controllers it is recommended to set this value
2599 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2600 buffers can be full shortly after enabling the interface
2601 on high Ethernet traffic.
2602 Defaults to 4 if not defined.
2604 - CONFIG_ENV_MAX_ENTRIES
2606 Maximum number of entries in the hash table that is used
2607 internally to store the environment settings. The default
2608 setting is supposed to be generous and should work in most
2609 cases. This setting can be used to tune behaviour; see
2610 lib/hashtable.c for details.
2612 The following definitions that deal with the placement and management
2613 of environment data (variable area); in general, we support the
2614 following configurations:
2616 - CONFIG_BUILD_ENVCRC:
2618 Builds up envcrc with the target environment so that external utils
2619 may easily extract it and embed it in final U-Boot images.
2621 - CONFIG_ENV_IS_IN_FLASH:
2623 Define this if the environment is in flash memory.
2625 a) The environment occupies one whole flash sector, which is
2626 "embedded" in the text segment with the U-Boot code. This
2627 happens usually with "bottom boot sector" or "top boot
2628 sector" type flash chips, which have several smaller
2629 sectors at the start or the end. For instance, such a
2630 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2631 such a case you would place the environment in one of the
2632 4 kB sectors - with U-Boot code before and after it. With
2633 "top boot sector" type flash chips, you would put the
2634 environment in one of the last sectors, leaving a gap
2635 between U-Boot and the environment.
2637 - CONFIG_ENV_OFFSET:
2639 Offset of environment data (variable area) to the
2640 beginning of flash memory; for instance, with bottom boot
2641 type flash chips the second sector can be used: the offset
2642 for this sector is given here.
2644 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2648 This is just another way to specify the start address of
2649 the flash sector containing the environment (instead of
2652 - CONFIG_ENV_SECT_SIZE:
2654 Size of the sector containing the environment.
2657 b) Sometimes flash chips have few, equal sized, BIG sectors.
2658 In such a case you don't want to spend a whole sector for
2663 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2664 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2665 of this flash sector for the environment. This saves
2666 memory for the RAM copy of the environment.
2668 It may also save flash memory if you decide to use this
2669 when your environment is "embedded" within U-Boot code,
2670 since then the remainder of the flash sector could be used
2671 for U-Boot code. It should be pointed out that this is
2672 STRONGLY DISCOURAGED from a robustness point of view:
2673 updating the environment in flash makes it always
2674 necessary to erase the WHOLE sector. If something goes
2675 wrong before the contents has been restored from a copy in
2676 RAM, your target system will be dead.
2678 - CONFIG_ENV_ADDR_REDUND
2679 CONFIG_ENV_SIZE_REDUND
2681 These settings describe a second storage area used to hold
2682 a redundant copy of the environment data, so that there is
2683 a valid backup copy in case there is a power failure during
2684 a "saveenv" operation.
2686 BE CAREFUL! Any changes to the flash layout, and some changes to the
2687 source code will make it necessary to adapt <board>/u-boot.lds*
2691 - CONFIG_ENV_IS_IN_NVRAM:
2693 Define this if you have some non-volatile memory device
2694 (NVRAM, battery buffered SRAM) which you want to use for the
2700 These two #defines are used to determine the memory area you
2701 want to use for environment. It is assumed that this memory
2702 can just be read and written to, without any special
2705 BE CAREFUL! The first access to the environment happens quite early
2706 in U-Boot initalization (when we try to get the setting of for the
2707 console baudrate). You *MUST* have mapped your NVRAM area then, or
2710 Please note that even with NVRAM we still use a copy of the
2711 environment in RAM: we could work on NVRAM directly, but we want to
2712 keep settings there always unmodified except somebody uses "saveenv"
2713 to save the current settings.
2716 - CONFIG_ENV_IS_IN_EEPROM:
2718 Use this if you have an EEPROM or similar serial access
2719 device and a driver for it.
2721 - CONFIG_ENV_OFFSET:
2724 These two #defines specify the offset and size of the
2725 environment area within the total memory of your EEPROM.
2727 - CONFIG_SYS_I2C_EEPROM_ADDR:
2728 If defined, specified the chip address of the EEPROM device.
2729 The default address is zero.
2731 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2732 If defined, the number of bits used to address bytes in a
2733 single page in the EEPROM device. A 64 byte page, for example
2734 would require six bits.
2736 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2737 If defined, the number of milliseconds to delay between
2738 page writes. The default is zero milliseconds.
2740 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2741 The length in bytes of the EEPROM memory array address. Note
2742 that this is NOT the chip address length!
2744 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2745 EEPROM chips that implement "address overflow" are ones
2746 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2747 address and the extra bits end up in the "chip address" bit
2748 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2751 Note that we consider the length of the address field to
2752 still be one byte because the extra address bits are hidden
2753 in the chip address.
2755 - CONFIG_SYS_EEPROM_SIZE:
2756 The size in bytes of the EEPROM device.
2758 - CONFIG_ENV_EEPROM_IS_ON_I2C
2759 define this, if you have I2C and SPI activated, and your
2760 EEPROM, which holds the environment, is on the I2C bus.
2762 - CONFIG_I2C_ENV_EEPROM_BUS
2763 if you have an Environment on an EEPROM reached over
2764 I2C muxes, you can define here, how to reach this
2765 EEPROM. For example:
2767 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2769 EEPROM which holds the environment, is reached over
2770 a pca9547 i2c mux with address 0x70, channel 3.
2772 - CONFIG_ENV_IS_IN_DATAFLASH:
2774 Define this if you have a DataFlash memory device which you
2775 want to use for the environment.
2777 - CONFIG_ENV_OFFSET:
2781 These three #defines specify the offset and size of the
2782 environment area within the total memory of your DataFlash placed
2783 at the specified address.
2785 - CONFIG_ENV_IS_IN_NAND:
2787 Define this if you have a NAND device which you want to use
2788 for the environment.
2790 - CONFIG_ENV_OFFSET:
2793 These two #defines specify the offset and size of the environment
2794 area within the first NAND device. CONFIG_ENV_OFFSET must be
2795 aligned to an erase block boundary.
2797 - CONFIG_ENV_OFFSET_REDUND (optional):
2799 This setting describes a second storage area of CONFIG_ENV_SIZE
2800 size used to hold a redundant copy of the environment data, so
2801 that there is a valid backup copy in case there is a power failure
2802 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2803 aligned to an erase block boundary.
2805 - CONFIG_ENV_RANGE (optional):
2807 Specifies the length of the region in which the environment
2808 can be written. This should be a multiple of the NAND device's
2809 block size. Specifying a range with more erase blocks than
2810 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2811 the range to be avoided.
2813 - CONFIG_ENV_OFFSET_OOB (optional):
2815 Enables support for dynamically retrieving the offset of the
2816 environment from block zero's out-of-band data. The
2817 "nand env.oob" command can be used to record this offset.
2818 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2819 using CONFIG_ENV_OFFSET_OOB.
2821 - CONFIG_NAND_ENV_DST
2823 Defines address in RAM to which the nand_spl code should copy the
2824 environment. If redundant environment is used, it will be copied to
2825 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2827 - CONFIG_SYS_SPI_INIT_OFFSET
2829 Defines offset to the initial SPI buffer area in DPRAM. The
2830 area is used at an early stage (ROM part) if the environment
2831 is configured to reside in the SPI EEPROM: We need a 520 byte
2832 scratch DPRAM area. It is used between the two initialization
2833 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2834 to be a good choice since it makes it far enough from the
2835 start of the data area as well as from the stack pointer.
2837 Please note that the environment is read-only until the monitor
2838 has been relocated to RAM and a RAM copy of the environment has been
2839 created; also, when using EEPROM you will have to use getenv_f()
2840 until then to read environment variables.
2842 The environment is protected by a CRC32 checksum. Before the monitor
2843 is relocated into RAM, as a result of a bad CRC you will be working
2844 with the compiled-in default environment - *silently*!!! [This is
2845 necessary, because the first environment variable we need is the
2846 "baudrate" setting for the console - if we have a bad CRC, we don't
2847 have any device yet where we could complain.]
2849 Note: once the monitor has been relocated, then it will complain if
2850 the default environment is used; a new CRC is computed as soon as you
2851 use the "saveenv" command to store a valid environment.
2853 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2854 Echo the inverted Ethernet link state to the fault LED.
2856 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2857 also needs to be defined.
2859 - CONFIG_SYS_FAULT_MII_ADDR:
2860 MII address of the PHY to check for the Ethernet link state.
2862 - CONFIG_NS16550_MIN_FUNCTIONS:
2863 Define this if you desire to only have use of the NS16550_init
2864 and NS16550_putc functions for the serial driver located at
2865 drivers/serial/ns16550.c. This option is useful for saving
2866 space for already greatly restricted images, including but not
2867 limited to NAND_SPL configurations.
2869 Low Level (hardware related) configuration options:
2870 ---------------------------------------------------
2872 - CONFIG_SYS_CACHELINE_SIZE:
2873 Cache Line Size of the CPU.
2875 - CONFIG_SYS_DEFAULT_IMMR:
2876 Default address of the IMMR after system reset.
2878 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2879 and RPXsuper) to be able to adjust the position of
2880 the IMMR register after a reset.
2882 - CONFIG_SYS_CCSRBAR_DEFAULT:
2883 Default (power-on reset) physical address of CCSR on Freescale
2886 - CONFIG_SYS_CCSRBAR:
2887 Virtual address of CCSR. On a 32-bit build, this is typically
2888 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2890 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
2891 for cross-platform code that uses that macro instead.
2893 - CONFIG_SYS_CCSRBAR_PHYS:
2894 Physical address of CCSR. CCSR can be relocated to a new
2895 physical address, if desired. In this case, this macro should
2896 be set to that address. Otherwise, it should be set to the
2897 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2898 is typically relocated on 36-bit builds. It is recommended
2899 that this macro be defined via the _HIGH and _LOW macros:
2901 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2902 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2904 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
2905 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2906 either 0 (32-bit build) or 0xF (36-bit build). This macro is
2907 used in assembly code, so it must not contain typecasts or
2908 integer size suffixes (e.g. "ULL").
2910 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
2911 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2912 used in assembly code, so it must not contain typecasts or
2913 integer size suffixes (e.g. "ULL").
2915 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2916 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2917 forced to a value that ensures that CCSR is not relocated.
2919 - Floppy Disk Support:
2920 CONFIG_SYS_FDC_DRIVE_NUMBER
2922 the default drive number (default value 0)
2924 CONFIG_SYS_ISA_IO_STRIDE
2926 defines the spacing between FDC chipset registers
2929 CONFIG_SYS_ISA_IO_OFFSET
2931 defines the offset of register from address. It
2932 depends on which part of the data bus is connected to
2933 the FDC chipset. (default value 0)
2935 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2936 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2939 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2940 fdc_hw_init() is called at the beginning of the FDC
2941 setup. fdc_hw_init() must be provided by the board
2942 source code. It is used to make hardware dependant
2946 Most IDE controllers were designed to be connected with PCI
2947 interface. Only few of them were designed for AHB interface.
2948 When software is doing ATA command and data transfer to
2949 IDE devices through IDE-AHB controller, some additional
2950 registers accessing to these kind of IDE-AHB controller
2953 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2954 DO NOT CHANGE unless you know exactly what you're
2955 doing! (11-4) [MPC8xx/82xx systems only]
2957 - CONFIG_SYS_INIT_RAM_ADDR:
2959 Start address of memory area that can be used for
2960 initial data and stack; please note that this must be
2961 writable memory that is working WITHOUT special
2962 initialization, i. e. you CANNOT use normal RAM which
2963 will become available only after programming the
2964 memory controller and running certain initialization
2967 U-Boot uses the following memory types:
2968 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2969 - MPC824X: data cache
2970 - PPC4xx: data cache
2972 - CONFIG_SYS_GBL_DATA_OFFSET:
2974 Offset of the initial data structure in the memory
2975 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2976 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2977 data is located at the end of the available space
2978 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2979 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2980 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2981 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2984 On the MPC824X (or other systems that use the data
2985 cache for initial memory) the address chosen for
2986 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2987 point to an otherwise UNUSED address space between
2988 the top of RAM and the start of the PCI space.
2990 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2992 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2994 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2996 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2998 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3000 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3002 - CONFIG_SYS_OR_TIMING_SDRAM:
3005 - CONFIG_SYS_MAMR_PTA:
3006 periodic timer for refresh
3008 - CONFIG_SYS_DER: Debug Event Register (37-47)
3010 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3011 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3012 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3013 CONFIG_SYS_BR1_PRELIM:
3014 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3016 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3017 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3018 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3019 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3021 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3022 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3023 Machine Mode Register and Memory Periodic Timer
3024 Prescaler definitions (SDRAM timing)
3026 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3027 enable I2C microcode relocation patch (MPC8xx);
3028 define relocation offset in DPRAM [DSP2]
3030 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3031 enable SMC microcode relocation patch (MPC8xx);
3032 define relocation offset in DPRAM [SMC1]
3034 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3035 enable SPI microcode relocation patch (MPC8xx);
3036 define relocation offset in DPRAM [SCC4]
3038 - CONFIG_SYS_USE_OSCCLK:
3039 Use OSCM clock mode on MBX8xx board. Be careful,
3040 wrong setting might damage your board. Read
3041 doc/README.MBX before setting this variable!
3043 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3044 Offset of the bootmode word in DPRAM used by post
3045 (Power On Self Tests). This definition overrides
3046 #define'd default value in commproc.h resp.
3049 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3050 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3051 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3052 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3053 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3054 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3055 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3056 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3057 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3059 - CONFIG_PCI_DISABLE_PCIE:
3060 Disable PCI-Express on systems where it is supported but not
3064 Chip has SRIO or not
3067 Board has SRIO 1 port available
3070 Board has SRIO 2 port available
3072 - CONFIG_SYS_SRIOn_MEM_VIRT:
3073 Virtual Address of SRIO port 'n' memory region
3075 - CONFIG_SYS_SRIOn_MEM_PHYS:
3076 Physical Address of SRIO port 'n' memory region
3078 - CONFIG_SYS_SRIOn_MEM_SIZE:
3079 Size of SRIO port 'n' memory region
3081 - CONFIG_SYS_NDFC_16
3082 Defined to tell the NDFC that the NAND chip is using a
3085 - CONFIG_SYS_NDFC_EBC0_CFG
3086 Sets the EBC0_CFG register for the NDFC. If not defined
3087 a default value will be used.
3090 Get DDR timing information from an I2C EEPROM. Common
3091 with pluggable memory modules such as SODIMMs
3094 I2C address of the SPD EEPROM
3096 - CONFIG_SYS_SPD_BUS_NUM
3097 If SPD EEPROM is on an I2C bus other than the first
3098 one, specify here. Note that the value must resolve
3099 to something your driver can deal with.
3101 - CONFIG_SYS_DDR_RAW_TIMING
3102 Get DDR timing information from other than SPD. Common with
3103 soldered DDR chips onboard without SPD. DDR raw timing
3104 parameters are extracted from datasheet and hard-coded into
3105 header files or board specific files.
3107 - CONFIG_FSL_DDR_INTERACTIVE
3108 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3110 - CONFIG_SYS_83XX_DDR_USES_CS0
3111 Only for 83xx systems. If specified, then DDR should
3112 be configured using CS0 and CS1 instead of CS2 and CS3.
3114 - CONFIG_ETHER_ON_FEC[12]
3115 Define to enable FEC[12] on a 8xx series processor.
3117 - CONFIG_FEC[12]_PHY
3118 Define to the hardcoded PHY address which corresponds
3119 to the given FEC; i. e.
3120 #define CONFIG_FEC1_PHY 4
3121 means that the PHY with address 4 is connected to FEC1
3123 When set to -1, means to probe for first available.
3125 - CONFIG_FEC[12]_PHY_NORXERR
3126 The PHY does not have a RXERR line (RMII only).
3127 (so program the FEC to ignore it).
3130 Enable RMII mode for all FECs.
3131 Note that this is a global option, we can't
3132 have one FEC in standard MII mode and another in RMII mode.
3134 - CONFIG_CRC32_VERIFY
3135 Add a verify option to the crc32 command.
3138 => crc32 -v <address> <count> <crc32>
3140 Where address/count indicate a memory area
3141 and crc32 is the correct crc32 which the
3145 Add the "loopw" memory command. This only takes effect if
3146 the memory commands are activated globally (CONFIG_CMD_MEM).
3149 Add the "mdc" and "mwc" memory commands. These are cyclic
3154 This command will print 4 bytes (10,11,12,13) each 500 ms.
3156 => mwc.l 100 12345678 10
3157 This command will write 12345678 to address 100 all 10 ms.
3159 This only takes effect if the memory commands are activated
3160 globally (CONFIG_CMD_MEM).
3162 - CONFIG_SKIP_LOWLEVEL_INIT
3163 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3164 low level initializations (like setting up the memory
3165 controller) are omitted and/or U-Boot does not
3166 relocate itself into RAM.
3168 Normally this variable MUST NOT be defined. The only
3169 exception is when U-Boot is loaded (to RAM) by some
3170 other boot loader or by a debugger which performs
3171 these initializations itself.
3174 Modifies the behaviour of start.S when compiling a loader
3175 that is executed before the actual U-Boot. E.g. when
3176 compiling a NAND SPL.
3178 - CONFIG_USE_ARCH_MEMCPY
3179 CONFIG_USE_ARCH_MEMSET
3180 If these options are used a optimized version of memcpy/memset will
3181 be used if available. These functions may be faster under some
3182 conditions but may increase the binary size.
3184 Building the Software:
3185 ======================
3187 Building U-Boot has been tested in several native build environments
3188 and in many different cross environments. Of course we cannot support
3189 all possibly existing versions of cross development tools in all
3190 (potentially obsolete) versions. In case of tool chain problems we
3191 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3192 which is extensively used to build and test U-Boot.
3194 If you are not using a native environment, it is assumed that you
3195 have GNU cross compiling tools available in your path. In this case,
3196 you must set the environment variable CROSS_COMPILE in your shell.
3197 Note that no changes to the Makefile or any other source files are
3198 necessary. For example using the ELDK on a 4xx CPU, please enter:
3200 $ CROSS_COMPILE=ppc_4xx-
3201 $ export CROSS_COMPILE
3203 Note: If you wish to generate Windows versions of the utilities in
3204 the tools directory you can use the MinGW toolchain
3205 (http://www.mingw.org). Set your HOST tools to the MinGW
3206 toolchain and execute 'make tools'. For example:
3208 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3210 Binaries such as tools/mkimage.exe will be created which can
3211 be executed on computers running Windows.
3213 U-Boot is intended to be simple to build. After installing the
3214 sources you must configure U-Boot for one specific board type. This
3219 where "NAME_config" is the name of one of the existing configu-
3220 rations; see the main Makefile for supported names.
3222 Note: for some board special configuration names may exist; check if
3223 additional information is available from the board vendor; for
3224 instance, the TQM823L systems are available without (standard)
3225 or with LCD support. You can select such additional "features"
3226 when choosing the configuration, i. e.
3229 - will configure for a plain TQM823L, i. e. no LCD support
3231 make TQM823L_LCD_config
3232 - will configure for a TQM823L with U-Boot console on LCD
3237 Finally, type "make all", and you should get some working U-Boot
3238 images ready for download to / installation on your system:
3240 - "u-boot.bin" is a raw binary image
3241 - "u-boot" is an image in ELF binary format
3242 - "u-boot.srec" is in Motorola S-Record format
3244 By default the build is performed locally and the objects are saved
3245 in the source directory. One of the two methods can be used to change
3246 this behavior and build U-Boot to some external directory:
3248 1. Add O= to the make command line invocations:
3250 make O=/tmp/build distclean
3251 make O=/tmp/build NAME_config
3252 make O=/tmp/build all
3254 2. Set environment variable BUILD_DIR to point to the desired location:
3256 export BUILD_DIR=/tmp/build
3261 Note that the command line "O=" setting overrides the BUILD_DIR environment
3265 Please be aware that the Makefiles assume you are using GNU make, so
3266 for instance on NetBSD you might need to use "gmake" instead of
3270 If the system board that you have is not listed, then you will need
3271 to port U-Boot to your hardware platform. To do this, follow these
3274 1. Add a new configuration option for your board to the toplevel
3275 "Makefile" and to the "MAKEALL" script, using the existing
3276 entries as examples. Note that here and at many other places
3277 boards and other names are listed in alphabetical sort order. Please
3279 2. Create a new directory to hold your board specific code. Add any
3280 files you need. In your board directory, you will need at least
3281 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3282 3. Create a new configuration file "include/configs/<board>.h" for
3284 3. If you're porting U-Boot to a new CPU, then also create a new
3285 directory to hold your CPU specific code. Add any files you need.
3286 4. Run "make <board>_config" with your new name.
3287 5. Type "make", and you should get a working "u-boot.srec" file
3288 to be installed on your target system.
3289 6. Debug and solve any problems that might arise.
3290 [Of course, this last step is much harder than it sounds.]
3293 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3294 ==============================================================
3296 If you have modified U-Boot sources (for instance added a new board
3297 or support for new devices, a new CPU, etc.) you are expected to
3298 provide feedback to the other developers. The feedback normally takes
3299 the form of a "patch", i. e. a context diff against a certain (latest
3300 official or latest in the git repository) version of U-Boot sources.
3302 But before you submit such a patch, please verify that your modifi-
3303 cation did not break existing code. At least make sure that *ALL* of
3304 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3305 just run the "MAKEALL" script, which will configure and build U-Boot
3306 for ALL supported system. Be warned, this will take a while. You can
3307 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3308 environment variable to the script, i. e. to use the ELDK cross tools
3311 CROSS_COMPILE=ppc_8xx- MAKEALL
3313 or to build on a native PowerPC system you can type
3315 CROSS_COMPILE=' ' MAKEALL
3317 When using the MAKEALL script, the default behaviour is to build
3318 U-Boot in the source directory. This location can be changed by
3319 setting the BUILD_DIR environment variable. Also, for each target
3320 built, the MAKEALL script saves two log files (<target>.ERR and
3321 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3322 location can be changed by setting the MAKEALL_LOGDIR environment
3323 variable. For example:
3325 export BUILD_DIR=/tmp/build
3326 export MAKEALL_LOGDIR=/tmp/log
3327 CROSS_COMPILE=ppc_8xx- MAKEALL
3329 With the above settings build objects are saved in the /tmp/build,
3330 log files are saved in the /tmp/log and the source tree remains clean
3331 during the whole build process.
3334 See also "U-Boot Porting Guide" below.
3337 Monitor Commands - Overview:
3338 ============================
3340 go - start application at address 'addr'
3341 run - run commands in an environment variable
3342 bootm - boot application image from memory
3343 bootp - boot image via network using BootP/TFTP protocol
3344 tftpboot- boot image via network using TFTP protocol
3345 and env variables "ipaddr" and "serverip"
3346 (and eventually "gatewayip")
3347 rarpboot- boot image via network using RARP/TFTP protocol
3348 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3349 loads - load S-Record file over serial line
3350 loadb - load binary file over serial line (kermit mode)
3352 mm - memory modify (auto-incrementing)
3353 nm - memory modify (constant address)
3354 mw - memory write (fill)
3356 cmp - memory compare
3357 crc32 - checksum calculation
3358 i2c - I2C sub-system
3359 sspi - SPI utility commands
3360 base - print or set address offset
3361 printenv- print environment variables
3362 setenv - set environment variables
3363 saveenv - save environment variables to persistent storage
3364 protect - enable or disable FLASH write protection
3365 erase - erase FLASH memory
3366 flinfo - print FLASH memory information
3367 bdinfo - print Board Info structure
3368 iminfo - print header information for application image
3369 coninfo - print console devices and informations
3370 ide - IDE sub-system
3371 loop - infinite loop on address range
3372 loopw - infinite write loop on address range
3373 mtest - simple RAM test
3374 icache - enable or disable instruction cache
3375 dcache - enable or disable data cache
3376 reset - Perform RESET of the CPU
3377 echo - echo args to console
3378 version - print monitor version
3379 help - print online help
3380 ? - alias for 'help'
3383 Monitor Commands - Detailed Description:
3384 ========================================
3388 For now: just type "help <command>".
3391 Environment Variables:
3392 ======================
3394 U-Boot supports user configuration using Environment Variables which
3395 can be made persistent by saving to Flash memory.
3397 Environment Variables are set using "setenv", printed using
3398 "printenv", and saved to Flash using "saveenv". Using "setenv"
3399 without a value can be used to delete a variable from the
3400 environment. As long as you don't save the environment you are
3401 working with an in-memory copy. In case the Flash area containing the
3402 environment is erased by accident, a default environment is provided.
3404 Some configuration options can be set using Environment Variables.
3406 List of environment variables (most likely not complete):
3408 baudrate - see CONFIG_BAUDRATE
3410 bootdelay - see CONFIG_BOOTDELAY
3412 bootcmd - see CONFIG_BOOTCOMMAND
3414 bootargs - Boot arguments when booting an RTOS image
3416 bootfile - Name of the image to load with TFTP
3418 bootm_low - Memory range available for image processing in the bootm
3419 command can be restricted. This variable is given as
3420 a hexadecimal number and defines lowest address allowed
3421 for use by the bootm command. See also "bootm_size"
3422 environment variable. Address defined by "bootm_low" is
3423 also the base of the initial memory mapping for the Linux
3424 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3427 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3428 This variable is given as a hexadecimal number and it
3429 defines the size of the memory region starting at base
3430 address bootm_low that is accessible by the Linux kernel
3431 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3432 as the default value if it is defined, and bootm_size is
3435 bootm_size - Memory range available for image processing in the bootm
3436 command can be restricted. This variable is given as
3437 a hexadecimal number and defines the size of the region
3438 allowed for use by the bootm command. See also "bootm_low"
3439 environment variable.
3441 updatefile - Location of the software update file on a TFTP server, used
3442 by the automatic software update feature. Please refer to
3443 documentation in doc/README.update for more details.
3445 autoload - if set to "no" (any string beginning with 'n'),
3446 "bootp" will just load perform a lookup of the
3447 configuration from the BOOTP server, but not try to
3448 load any image using TFTP
3450 autostart - if set to "yes", an image loaded using the "bootp",
3451 "rarpboot", "tftpboot" or "diskboot" commands will
3452 be automatically started (by internally calling
3455 If set to "no", a standalone image passed to the
3456 "bootm" command will be copied to the load address
3457 (and eventually uncompressed), but NOT be started.
3458 This can be used to load and uncompress arbitrary
3461 fdt_high - if set this restricts the maximum address that the
3462 flattened device tree will be copied into upon boot.
3463 If this is set to the special value 0xFFFFFFFF then
3464 the fdt will not be copied at all on boot. For this
3465 to work it must reside in writable memory, have
3466 sufficient padding on the end of it for u-boot to
3467 add the information it needs into it, and the memory
3468 must be accessible by the kernel.
3470 i2cfast - (PPC405GP|PPC405EP only)
3471 if set to 'y' configures Linux I2C driver for fast
3472 mode (400kHZ). This environment variable is used in
3473 initialization code. So, for changes to be effective
3474 it must be saved and board must be reset.
3476 initrd_high - restrict positioning of initrd images:
3477 If this variable is not set, initrd images will be
3478 copied to the highest possible address in RAM; this
3479 is usually what you want since it allows for
3480 maximum initrd size. If for some reason you want to
3481 make sure that the initrd image is loaded below the
3482 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3483 variable to a value of "no" or "off" or "0".
3484 Alternatively, you can set it to a maximum upper
3485 address to use (U-Boot will still check that it
3486 does not overwrite the U-Boot stack and data).
3488 For instance, when you have a system with 16 MB
3489 RAM, and want to reserve 4 MB from use by Linux,
3490 you can do this by adding "mem=12M" to the value of
3491 the "bootargs" variable. However, now you must make
3492 sure that the initrd image is placed in the first
3493 12 MB as well - this can be done with
3495 setenv initrd_high 00c00000
3497 If you set initrd_high to 0xFFFFFFFF, this is an
3498 indication to U-Boot that all addresses are legal
3499 for the Linux kernel, including addresses in flash
3500 memory. In this case U-Boot will NOT COPY the
3501 ramdisk at all. This may be useful to reduce the
3502 boot time on your system, but requires that this
3503 feature is supported by your Linux kernel.
3505 ipaddr - IP address; needed for tftpboot command
3507 loadaddr - Default load address for commands like "bootp",
3508 "rarpboot", "tftpboot", "loadb" or "diskboot"
3510 loads_echo - see CONFIG_LOADS_ECHO
3512 serverip - TFTP server IP address; needed for tftpboot command
3514 bootretry - see CONFIG_BOOT_RETRY_TIME
3516 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3518 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3520 ethprime - controls which interface is used first.
3522 ethact - controls which interface is currently active.
3523 For example you can do the following
3525 => setenv ethact FEC
3526 => ping 192.168.0.1 # traffic sent on FEC
3527 => setenv ethact SCC
3528 => ping 10.0.0.1 # traffic sent on SCC
3530 ethrotate - When set to "no" U-Boot does not go through all
3531 available network interfaces.
3532 It just stays at the currently selected interface.
3534 netretry - When set to "no" each network operation will
3535 either succeed or fail without retrying.
3536 When set to "once" the network operation will
3537 fail when all the available network interfaces
3538 are tried once without success.
3539 Useful on scripts which control the retry operation
3542 npe_ucode - set load address for the NPE microcode
3544 tftpsrcport - If this is set, the value is used for TFTP's
3547 tftpdstport - If this is set, the value is used for TFTP's UDP
3548 destination port instead of the Well Know Port 69.
3550 tftpblocksize - Block size to use for TFTP transfers; if not set,
3551 we use the TFTP server's default block size
3553 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3554 seconds, minimum value is 1000 = 1 second). Defines
3555 when a packet is considered to be lost so it has to
3556 be retransmitted. The default is 5000 = 5 seconds.
3557 Lowering this value may make downloads succeed
3558 faster in networks with high packet loss rates or
3559 with unreliable TFTP servers.
3561 vlan - When set to a value < 4095 the traffic over
3562 Ethernet is encapsulated/received over 802.1q
3565 The following image location variables contain the location of images
3566 used in booting. The "Image" column gives the role of the image and is
3567 not an environment variable name. The other columns are environment
3568 variable names. "File Name" gives the name of the file on a TFTP
3569 server, "RAM Address" gives the location in RAM the image will be
3570 loaded to, and "Flash Location" gives the image's address in NOR
3571 flash or offset in NAND flash.
3573 *Note* - these variables don't have to be defined for all boards, some
3574 boards currenlty use other variables for these purposes, and some
3575 boards use these variables for other purposes.
3577 Image File Name RAM Address Flash Location
3578 ----- --------- ----------- --------------
3579 u-boot u-boot u-boot_addr_r u-boot_addr
3580 Linux kernel bootfile kernel_addr_r kernel_addr
3581 device tree blob fdtfile fdt_addr_r fdt_addr
3582 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3584 The following environment variables may be used and automatically
3585 updated by the network boot commands ("bootp" and "rarpboot"),
3586 depending the information provided by your boot server:
3588 bootfile - see above
3589 dnsip - IP address of your Domain Name Server
3590 dnsip2 - IP address of your secondary Domain Name Server
3591 gatewayip - IP address of the Gateway (Router) to use
3592 hostname - Target hostname
3594 netmask - Subnet Mask
3595 rootpath - Pathname of the root filesystem on the NFS server
3596 serverip - see above
3599 There are two special Environment Variables:
3601 serial# - contains hardware identification information such
3602 as type string and/or serial number
3603 ethaddr - Ethernet address
3605 These variables can be set only once (usually during manufacturing of
3606 the board). U-Boot refuses to delete or overwrite these variables
3607 once they have been set once.
3610 Further special Environment Variables:
3612 ver - Contains the U-Boot version string as printed
3613 with the "version" command. This variable is
3614 readonly (see CONFIG_VERSION_VARIABLE).
3617 Please note that changes to some configuration parameters may take
3618 only effect after the next boot (yes, that's just like Windoze :-).
3621 Command Line Parsing:
3622 =====================
3624 There are two different command line parsers available with U-Boot:
3625 the old "simple" one, and the much more powerful "hush" shell:
3627 Old, simple command line parser:
3628 --------------------------------
3630 - supports environment variables (through setenv / saveenv commands)
3631 - several commands on one line, separated by ';'
3632 - variable substitution using "... ${name} ..." syntax
3633 - special characters ('$', ';') can be escaped by prefixing with '\',
3635 setenv bootcmd bootm \${address}
3636 - You can also escape text by enclosing in single apostrophes, for example:
3637 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3642 - similar to Bourne shell, with control structures like
3643 if...then...else...fi, for...do...done; while...do...done,
3644 until...do...done, ...
3645 - supports environment ("global") variables (through setenv / saveenv
3646 commands) and local shell variables (through standard shell syntax
3647 "name=value"); only environment variables can be used with "run"
3653 (1) If a command line (or an environment variable executed by a "run"
3654 command) contains several commands separated by semicolon, and
3655 one of these commands fails, then the remaining commands will be
3658 (2) If you execute several variables with one call to run (i. e.
3659 calling run with a list of variables as arguments), any failing
3660 command will cause "run" to terminate, i. e. the remaining
3661 variables are not executed.
3663 Note for Redundant Ethernet Interfaces:
3664 =======================================
3666 Some boards come with redundant Ethernet interfaces; U-Boot supports
3667 such configurations and is capable of automatic selection of a
3668 "working" interface when needed. MAC assignment works as follows:
3670 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3671 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3672 "eth1addr" (=>eth1), "eth2addr", ...
3674 If the network interface stores some valid MAC address (for instance
3675 in SROM), this is used as default address if there is NO correspon-
3676 ding setting in the environment; if the corresponding environment
3677 variable is set, this overrides the settings in the card; that means:
3679 o If the SROM has a valid MAC address, and there is no address in the
3680 environment, the SROM's address is used.
3682 o If there is no valid address in the SROM, and a definition in the
3683 environment exists, then the value from the environment variable is
3686 o If both the SROM and the environment contain a MAC address, and
3687 both addresses are the same, this MAC address is used.
3689 o If both the SROM and the environment contain a MAC address, and the
3690 addresses differ, the value from the environment is used and a
3693 o If neither SROM nor the environment contain a MAC address, an error
3696 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3697 will be programmed into hardware as part of the initialization process. This
3698 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3699 The naming convention is as follows:
3700 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3705 U-Boot is capable of booting (and performing other auxiliary operations on)
3706 images in two formats:
3708 New uImage format (FIT)
3709 -----------------------
3711 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3712 to Flattened Device Tree). It allows the use of images with multiple
3713 components (several kernels, ramdisks, etc.), with contents protected by
3714 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3720 Old image format is based on binary files which can be basically anything,
3721 preceded by a special header; see the definitions in include/image.h for
3722 details; basically, the header defines the following image properties:
3724 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3725 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3726 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3727 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3729 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3730 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3731 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3732 * Compression Type (uncompressed, gzip, bzip2)
3738 The header is marked by a special Magic Number, and both the header
3739 and the data portions of the image are secured against corruption by
3746 Although U-Boot should support any OS or standalone application
3747 easily, the main focus has always been on Linux during the design of
3750 U-Boot includes many features that so far have been part of some
3751 special "boot loader" code within the Linux kernel. Also, any
3752 "initrd" images to be used are no longer part of one big Linux image;
3753 instead, kernel and "initrd" are separate images. This implementation
3754 serves several purposes:
3756 - the same features can be used for other OS or standalone
3757 applications (for instance: using compressed images to reduce the
3758 Flash memory footprint)
3760 - it becomes much easier to port new Linux kernel versions because
3761 lots of low-level, hardware dependent stuff are done by U-Boot
3763 - the same Linux kernel image can now be used with different "initrd"
3764 images; of course this also means that different kernel images can
3765 be run with the same "initrd". This makes testing easier (you don't
3766 have to build a new "zImage.initrd" Linux image when you just
3767 change a file in your "initrd"). Also, a field-upgrade of the
3768 software is easier now.
3774 Porting Linux to U-Boot based systems:
3775 ---------------------------------------
3777 U-Boot cannot save you from doing all the necessary modifications to
3778 configure the Linux device drivers for use with your target hardware
3779 (no, we don't intend to provide a full virtual machine interface to
3782 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3784 Just make sure your machine specific header file (for instance
3785 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3786 Information structure as we define in include/asm-<arch>/u-boot.h,
3787 and make sure that your definition of IMAP_ADDR uses the same value
3788 as your U-Boot configuration in CONFIG_SYS_IMMR.
3791 Configuring the Linux kernel:
3792 -----------------------------
3794 No specific requirements for U-Boot. Make sure you have some root
3795 device (initial ramdisk, NFS) for your target system.
3798 Building a Linux Image:
3799 -----------------------
3801 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3802 not used. If you use recent kernel source, a new build target
3803 "uImage" will exist which automatically builds an image usable by
3804 U-Boot. Most older kernels also have support for a "pImage" target,
3805 which was introduced for our predecessor project PPCBoot and uses a
3806 100% compatible format.
3815 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3816 encapsulate a compressed Linux kernel image with header information,
3817 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3819 * build a standard "vmlinux" kernel image (in ELF binary format):
3821 * convert the kernel into a raw binary image:
3823 ${CROSS_COMPILE}-objcopy -O binary \
3824 -R .note -R .comment \
3825 -S vmlinux linux.bin
3827 * compress the binary image:
3831 * package compressed binary image for U-Boot:
3833 mkimage -A ppc -O linux -T kernel -C gzip \
3834 -a 0 -e 0 -n "Linux Kernel Image" \
3835 -d linux.bin.gz uImage
3838 The "mkimage" tool can also be used to create ramdisk images for use
3839 with U-Boot, either separated from the Linux kernel image, or
3840 combined into one file. "mkimage" encapsulates the images with a 64
3841 byte header containing information about target architecture,
3842 operating system, image type, compression method, entry points, time
3843 stamp, CRC32 checksums, etc.
3845 "mkimage" can be called in two ways: to verify existing images and
3846 print the header information, or to build new images.
3848 In the first form (with "-l" option) mkimage lists the information
3849 contained in the header of an existing U-Boot image; this includes
3850 checksum verification:
3852 tools/mkimage -l image
3853 -l ==> list image header information
3855 The second form (with "-d" option) is used to build a U-Boot image
3856 from a "data file" which is used as image payload:
3858 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3859 -n name -d data_file image
3860 -A ==> set architecture to 'arch'
3861 -O ==> set operating system to 'os'
3862 -T ==> set image type to 'type'
3863 -C ==> set compression type 'comp'
3864 -a ==> set load address to 'addr' (hex)
3865 -e ==> set entry point to 'ep' (hex)
3866 -n ==> set image name to 'name'
3867 -d ==> use image data from 'datafile'
3869 Right now, all Linux kernels for PowerPC systems use the same load
3870 address (0x00000000), but the entry point address depends on the
3873 - 2.2.x kernels have the entry point at 0x0000000C,
3874 - 2.3.x and later kernels have the entry point at 0x00000000.
3876 So a typical call to build a U-Boot image would read:
3878 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3879 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3880 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3881 > examples/uImage.TQM850L
3882 Image Name: 2.4.4 kernel for TQM850L
3883 Created: Wed Jul 19 02:34:59 2000
3884 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3885 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3886 Load Address: 0x00000000
3887 Entry Point: 0x00000000
3889 To verify the contents of the image (or check for corruption):
3891 -> tools/mkimage -l examples/uImage.TQM850L
3892 Image Name: 2.4.4 kernel for TQM850L
3893 Created: Wed Jul 19 02:34:59 2000
3894 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3895 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3896 Load Address: 0x00000000
3897 Entry Point: 0x00000000
3899 NOTE: for embedded systems where boot time is critical you can trade
3900 speed for memory and install an UNCOMPRESSED image instead: this
3901 needs more space in Flash, but boots much faster since it does not
3902 need to be uncompressed:
3904 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3905 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3906 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3907 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3908 > examples/uImage.TQM850L-uncompressed
3909 Image Name: 2.4.4 kernel for TQM850L
3910 Created: Wed Jul 19 02:34:59 2000
3911 Image Type: PowerPC Linux Kernel Image (uncompressed)
3912 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3913 Load Address: 0x00000000
3914 Entry Point: 0x00000000
3917 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3918 when your kernel is intended to use an initial ramdisk:
3920 -> tools/mkimage -n 'Simple Ramdisk Image' \
3921 > -A ppc -O linux -T ramdisk -C gzip \
3922 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3923 Image Name: Simple Ramdisk Image
3924 Created: Wed Jan 12 14:01:50 2000
3925 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3926 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3927 Load Address: 0x00000000
3928 Entry Point: 0x00000000
3931 Installing a Linux Image:
3932 -------------------------
3934 To downloading a U-Boot image over the serial (console) interface,
3935 you must convert the image to S-Record format:
3937 objcopy -I binary -O srec examples/image examples/image.srec
3939 The 'objcopy' does not understand the information in the U-Boot
3940 image header, so the resulting S-Record file will be relative to
3941 address 0x00000000. To load it to a given address, you need to
3942 specify the target address as 'offset' parameter with the 'loads'
3945 Example: install the image to address 0x40100000 (which on the
3946 TQM8xxL is in the first Flash bank):
3948 => erase 40100000 401FFFFF
3954 ## Ready for S-Record download ...
3955 ~>examples/image.srec
3956 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3958 15989 15990 15991 15992
3959 [file transfer complete]
3961 ## Start Addr = 0x00000000
3964 You can check the success of the download using the 'iminfo' command;
3965 this includes a checksum verification so you can be sure no data
3966 corruption happened:
3970 ## Checking Image at 40100000 ...
3971 Image Name: 2.2.13 for initrd on TQM850L
3972 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3973 Data Size: 335725 Bytes = 327 kB = 0 MB
3974 Load Address: 00000000
3975 Entry Point: 0000000c
3976 Verifying Checksum ... OK
3982 The "bootm" command is used to boot an application that is stored in
3983 memory (RAM or Flash). In case of a Linux kernel image, the contents
3984 of the "bootargs" environment variable is passed to the kernel as
3985 parameters. You can check and modify this variable using the
3986 "printenv" and "setenv" commands:
3989 => printenv bootargs
3990 bootargs=root=/dev/ram
3992 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3994 => printenv bootargs
3995 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3998 ## Booting Linux kernel at 40020000 ...
3999 Image Name: 2.2.13 for NFS on TQM850L
4000 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4001 Data Size: 381681 Bytes = 372 kB = 0 MB
4002 Load Address: 00000000
4003 Entry Point: 0000000c
4004 Verifying Checksum ... OK
4005 Uncompressing Kernel Image ... OK
4006 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
4007 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4008 time_init: decrementer frequency = 187500000/60
4009 Calibrating delay loop... 49.77 BogoMIPS
4010 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4013 If you want to boot a Linux kernel with initial RAM disk, you pass
4014 the memory addresses of both the kernel and the initrd image (PPBCOOT
4015 format!) to the "bootm" command:
4017 => imi 40100000 40200000
4019 ## Checking Image at 40100000 ...
4020 Image Name: 2.2.13 for initrd on TQM850L
4021 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4022 Data Size: 335725 Bytes = 327 kB = 0 MB
4023 Load Address: 00000000
4024 Entry Point: 0000000c
4025 Verifying Checksum ... OK
4027 ## Checking Image at 40200000 ...
4028 Image Name: Simple Ramdisk Image
4029 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4030 Data Size: 566530 Bytes = 553 kB = 0 MB
4031 Load Address: 00000000
4032 Entry Point: 00000000
4033 Verifying Checksum ... OK
4035 => bootm 40100000 40200000
4036 ## Booting Linux kernel at 40100000 ...
4037 Image Name: 2.2.13 for initrd on TQM850L
4038 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4039 Data Size: 335725 Bytes = 327 kB = 0 MB
4040 Load Address: 00000000
4041 Entry Point: 0000000c
4042 Verifying Checksum ... OK
4043 Uncompressing Kernel Image ... OK
4044 ## Loading RAMDisk Image at 40200000 ...
4045 Image Name: Simple Ramdisk Image
4046 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4047 Data Size: 566530 Bytes = 553 kB = 0 MB
4048 Load Address: 00000000
4049 Entry Point: 00000000
4050 Verifying Checksum ... OK
4051 Loading Ramdisk ... OK
4052 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
4053 Boot arguments: root=/dev/ram
4054 time_init: decrementer frequency = 187500000/60
4055 Calibrating delay loop... 49.77 BogoMIPS
4057 RAMDISK: Compressed image found at block 0
4058 VFS: Mounted root (ext2 filesystem).
4062 Boot Linux and pass a flat device tree:
4065 First, U-Boot must be compiled with the appropriate defines. See the section
4066 titled "Linux Kernel Interface" above for a more in depth explanation. The
4067 following is an example of how to start a kernel and pass an updated
4073 oft=oftrees/mpc8540ads.dtb
4074 => tftp $oftaddr $oft
4075 Speed: 1000, full duplex
4077 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4078 Filename 'oftrees/mpc8540ads.dtb'.
4079 Load address: 0x300000
4082 Bytes transferred = 4106 (100a hex)
4083 => tftp $loadaddr $bootfile
4084 Speed: 1000, full duplex
4086 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4088 Load address: 0x200000
4089 Loading:############
4091 Bytes transferred = 1029407 (fb51f hex)
4096 => bootm $loadaddr - $oftaddr
4097 ## Booting image at 00200000 ...
4098 Image Name: Linux-2.6.17-dirty
4099 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4100 Data Size: 1029343 Bytes = 1005.2 kB
4101 Load Address: 00000000
4102 Entry Point: 00000000
4103 Verifying Checksum ... OK
4104 Uncompressing Kernel Image ... OK
4105 Booting using flat device tree at 0x300000
4106 Using MPC85xx ADS machine description
4107 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4111 More About U-Boot Image Types:
4112 ------------------------------
4114 U-Boot supports the following image types:
4116 "Standalone Programs" are directly runnable in the environment
4117 provided by U-Boot; it is expected that (if they behave
4118 well) you can continue to work in U-Boot after return from
4119 the Standalone Program.
4120 "OS Kernel Images" are usually images of some Embedded OS which
4121 will take over control completely. Usually these programs
4122 will install their own set of exception handlers, device
4123 drivers, set up the MMU, etc. - this means, that you cannot
4124 expect to re-enter U-Boot except by resetting the CPU.
4125 "RAMDisk Images" are more or less just data blocks, and their
4126 parameters (address, size) are passed to an OS kernel that is
4128 "Multi-File Images" contain several images, typically an OS
4129 (Linux) kernel image and one or more data images like
4130 RAMDisks. This construct is useful for instance when you want
4131 to boot over the network using BOOTP etc., where the boot
4132 server provides just a single image file, but you want to get
4133 for instance an OS kernel and a RAMDisk image.
4135 "Multi-File Images" start with a list of image sizes, each
4136 image size (in bytes) specified by an "uint32_t" in network
4137 byte order. This list is terminated by an "(uint32_t)0".
4138 Immediately after the terminating 0 follow the images, one by
4139 one, all aligned on "uint32_t" boundaries (size rounded up to
4140 a multiple of 4 bytes).
4142 "Firmware Images" are binary images containing firmware (like
4143 U-Boot or FPGA images) which usually will be programmed to
4146 "Script files" are command sequences that will be executed by
4147 U-Boot's command interpreter; this feature is especially
4148 useful when you configure U-Boot to use a real shell (hush)
4149 as command interpreter.
4155 One of the features of U-Boot is that you can dynamically load and
4156 run "standalone" applications, which can use some resources of
4157 U-Boot like console I/O functions or interrupt services.
4159 Two simple examples are included with the sources:
4164 'examples/hello_world.c' contains a small "Hello World" Demo
4165 application; it is automatically compiled when you build U-Boot.
4166 It's configured to run at address 0x00040004, so you can play with it
4170 ## Ready for S-Record download ...
4171 ~>examples/hello_world.srec
4172 1 2 3 4 5 6 7 8 9 10 11 ...
4173 [file transfer complete]
4175 ## Start Addr = 0x00040004
4177 => go 40004 Hello World! This is a test.
4178 ## Starting application at 0x00040004 ...
4189 Hit any key to exit ...
4191 ## Application terminated, rc = 0x0
4193 Another example, which demonstrates how to register a CPM interrupt
4194 handler with the U-Boot code, can be found in 'examples/timer.c'.
4195 Here, a CPM timer is set up to generate an interrupt every second.
4196 The interrupt service routine is trivial, just printing a '.'
4197 character, but this is just a demo program. The application can be
4198 controlled by the following keys:
4200 ? - print current values og the CPM Timer registers
4201 b - enable interrupts and start timer
4202 e - stop timer and disable interrupts
4203 q - quit application
4206 ## Ready for S-Record download ...
4207 ~>examples/timer.srec
4208 1 2 3 4 5 6 7 8 9 10 11 ...
4209 [file transfer complete]
4211 ## Start Addr = 0x00040004
4214 ## Starting application at 0x00040004 ...
4217 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4220 [q, b, e, ?] Set interval 1000000 us
4223 [q, b, e, ?] ........
4224 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4227 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4230 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4233 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4235 [q, b, e, ?] ...Stopping timer
4237 [q, b, e, ?] ## Application terminated, rc = 0x0
4243 Over time, many people have reported problems when trying to use the
4244 "minicom" terminal emulation program for serial download. I (wd)
4245 consider minicom to be broken, and recommend not to use it. Under
4246 Unix, I recommend to use C-Kermit for general purpose use (and
4247 especially for kermit binary protocol download ("loadb" command), and
4248 use "cu" for S-Record download ("loads" command).
4250 Nevertheless, if you absolutely want to use it try adding this
4251 configuration to your "File transfer protocols" section:
4253 Name Program Name U/D FullScr IO-Red. Multi
4254 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4255 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4261 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4262 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4264 Building requires a cross environment; it is known to work on
4265 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4266 need gmake since the Makefiles are not compatible with BSD make).
4267 Note that the cross-powerpc package does not install include files;
4268 attempting to build U-Boot will fail because <machine/ansi.h> is
4269 missing. This file has to be installed and patched manually:
4271 # cd /usr/pkg/cross/powerpc-netbsd/include
4273 # ln -s powerpc machine
4274 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4275 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4277 Native builds *don't* work due to incompatibilities between native
4278 and U-Boot include files.
4280 Booting assumes that (the first part of) the image booted is a
4281 stage-2 loader which in turn loads and then invokes the kernel
4282 proper. Loader sources will eventually appear in the NetBSD source
4283 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4284 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4287 Implementation Internals:
4288 =========================
4290 The following is not intended to be a complete description of every
4291 implementation detail. However, it should help to understand the
4292 inner workings of U-Boot and make it easier to port it to custom
4296 Initial Stack, Global Data:
4297 ---------------------------
4299 The implementation of U-Boot is complicated by the fact that U-Boot
4300 starts running out of ROM (flash memory), usually without access to
4301 system RAM (because the memory controller is not initialized yet).
4302 This means that we don't have writable Data or BSS segments, and BSS
4303 is not initialized as zero. To be able to get a C environment working
4304 at all, we have to allocate at least a minimal stack. Implementation
4305 options for this are defined and restricted by the CPU used: Some CPU
4306 models provide on-chip memory (like the IMMR area on MPC8xx and
4307 MPC826x processors), on others (parts of) the data cache can be
4308 locked as (mis-) used as memory, etc.
4310 Chris Hallinan posted a good summary of these issues to the
4311 U-Boot mailing list:
4313 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4314 From: "Chris Hallinan" <clh@net1plus.com>
4315 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4318 Correct me if I'm wrong, folks, but the way I understand it
4319 is this: Using DCACHE as initial RAM for Stack, etc, does not
4320 require any physical RAM backing up the cache. The cleverness
4321 is that the cache is being used as a temporary supply of
4322 necessary storage before the SDRAM controller is setup. It's
4323 beyond the scope of this list to explain the details, but you
4324 can see how this works by studying the cache architecture and
4325 operation in the architecture and processor-specific manuals.
4327 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4328 is another option for the system designer to use as an
4329 initial stack/RAM area prior to SDRAM being available. Either
4330 option should work for you. Using CS 4 should be fine if your
4331 board designers haven't used it for something that would
4332 cause you grief during the initial boot! It is frequently not
4335 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4336 with your processor/board/system design. The default value
4337 you will find in any recent u-boot distribution in
4338 walnut.h should work for you. I'd set it to a value larger
4339 than your SDRAM module. If you have a 64MB SDRAM module, set
4340 it above 400_0000. Just make sure your board has no resources
4341 that are supposed to respond to that address! That code in
4342 start.S has been around a while and should work as is when
4343 you get the config right.
4348 It is essential to remember this, since it has some impact on the C
4349 code for the initialization procedures:
4351 * Initialized global data (data segment) is read-only. Do not attempt
4354 * Do not use any uninitialized global data (or implicitely initialized
4355 as zero data - BSS segment) at all - this is undefined, initiali-
4356 zation is performed later (when relocating to RAM).
4358 * Stack space is very limited. Avoid big data buffers or things like
4361 Having only the stack as writable memory limits means we cannot use
4362 normal global data to share information beween the code. But it
4363 turned out that the implementation of U-Boot can be greatly
4364 simplified by making a global data structure (gd_t) available to all
4365 functions. We could pass a pointer to this data as argument to _all_
4366 functions, but this would bloat the code. Instead we use a feature of
4367 the GCC compiler (Global Register Variables) to share the data: we
4368 place a pointer (gd) to the global data into a register which we
4369 reserve for this purpose.
4371 When choosing a register for such a purpose we are restricted by the
4372 relevant (E)ABI specifications for the current architecture, and by
4373 GCC's implementation.
4375 For PowerPC, the following registers have specific use:
4377 R2: reserved for system use
4378 R3-R4: parameter passing and return values
4379 R5-R10: parameter passing
4380 R13: small data area pointer
4384 (U-Boot also uses R12 as internal GOT pointer. r12
4385 is a volatile register so r12 needs to be reset when
4386 going back and forth between asm and C)
4388 ==> U-Boot will use R2 to hold a pointer to the global data
4390 Note: on PPC, we could use a static initializer (since the
4391 address of the global data structure is known at compile time),
4392 but it turned out that reserving a register results in somewhat
4393 smaller code - although the code savings are not that big (on
4394 average for all boards 752 bytes for the whole U-Boot image,
4395 624 text + 127 data).
4397 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4398 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4400 ==> U-Boot will use P3 to hold a pointer to the global data
4402 On ARM, the following registers are used:
4404 R0: function argument word/integer result
4405 R1-R3: function argument word
4407 R10: stack limit (used only if stack checking if enabled)
4408 R11: argument (frame) pointer
4409 R12: temporary workspace
4412 R15: program counter
4414 ==> U-Boot will use R8 to hold a pointer to the global data
4416 On Nios II, the ABI is documented here:
4417 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4419 ==> U-Boot will use gp to hold a pointer to the global data
4421 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4422 to access small data sections, so gp is free.
4424 On NDS32, the following registers are used:
4426 R0-R1: argument/return
4428 R15: temporary register for assembler
4429 R16: trampoline register
4430 R28: frame pointer (FP)
4431 R29: global pointer (GP)
4432 R30: link register (LP)
4433 R31: stack pointer (SP)
4434 PC: program counter (PC)
4436 ==> U-Boot will use R10 to hold a pointer to the global data
4438 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4439 or current versions of GCC may "optimize" the code too much.
4444 U-Boot runs in system state and uses physical addresses, i.e. the
4445 MMU is not used either for address mapping nor for memory protection.
4447 The available memory is mapped to fixed addresses using the memory
4448 controller. In this process, a contiguous block is formed for each
4449 memory type (Flash, SDRAM, SRAM), even when it consists of several
4450 physical memory banks.
4452 U-Boot is installed in the first 128 kB of the first Flash bank (on
4453 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4454 booting and sizing and initializing DRAM, the code relocates itself
4455 to the upper end of DRAM. Immediately below the U-Boot code some
4456 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4457 configuration setting]. Below that, a structure with global Board
4458 Info data is placed, followed by the stack (growing downward).
4460 Additionally, some exception handler code is copied to the low 8 kB
4461 of DRAM (0x00000000 ... 0x00001FFF).
4463 So a typical memory configuration with 16 MB of DRAM could look like
4466 0x0000 0000 Exception Vector code
4469 0x0000 2000 Free for Application Use
4475 0x00FB FF20 Monitor Stack (Growing downward)
4476 0x00FB FFAC Board Info Data and permanent copy of global data
4477 0x00FC 0000 Malloc Arena
4480 0x00FE 0000 RAM Copy of Monitor Code
4481 ... eventually: LCD or video framebuffer
4482 ... eventually: pRAM (Protected RAM - unchanged by reset)
4483 0x00FF FFFF [End of RAM]
4486 System Initialization:
4487 ----------------------
4489 In the reset configuration, U-Boot starts at the reset entry point
4490 (on most PowerPC systems at address 0x00000100). Because of the reset
4491 configuration for CS0# this is a mirror of the onboard Flash memory.
4492 To be able to re-map memory U-Boot then jumps to its link address.
4493 To be able to implement the initialization code in C, a (small!)
4494 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4495 which provide such a feature like MPC8xx or MPC8260), or in a locked
4496 part of the data cache. After that, U-Boot initializes the CPU core,
4497 the caches and the SIU.
4499 Next, all (potentially) available memory banks are mapped using a
4500 preliminary mapping. For example, we put them on 512 MB boundaries
4501 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4502 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4503 programmed for SDRAM access. Using the temporary configuration, a
4504 simple memory test is run that determines the size of the SDRAM
4507 When there is more than one SDRAM bank, and the banks are of
4508 different size, the largest is mapped first. For equal size, the first
4509 bank (CS2#) is mapped first. The first mapping is always for address
4510 0x00000000, with any additional banks following immediately to create
4511 contiguous memory starting from 0.
4513 Then, the monitor installs itself at the upper end of the SDRAM area
4514 and allocates memory for use by malloc() and for the global Board
4515 Info data; also, the exception vector code is copied to the low RAM
4516 pages, and the final stack is set up.
4518 Only after this relocation will you have a "normal" C environment;
4519 until that you are restricted in several ways, mostly because you are
4520 running from ROM, and because the code will have to be relocated to a
4524 U-Boot Porting Guide:
4525 ----------------------
4527 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4531 int main(int argc, char *argv[])
4533 sighandler_t no_more_time;
4535 signal(SIGALRM, no_more_time);
4536 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4538 if (available_money > available_manpower) {
4539 Pay consultant to port U-Boot;
4543 Download latest U-Boot source;
4545 Subscribe to u-boot mailing list;
4548 email("Hi, I am new to U-Boot, how do I get started?");
4551 Read the README file in the top level directory;
4552 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4553 Read applicable doc/*.README;
4554 Read the source, Luke;
4555 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4558 if (available_money > toLocalCurrency ($2500))
4561 Add a lot of aggravation and time;
4563 if (a similar board exists) { /* hopefully... */
4564 cp -a board/<similar> board/<myboard>
4565 cp include/configs/<similar>.h include/configs/<myboard>.h
4567 Create your own board support subdirectory;
4568 Create your own board include/configs/<myboard>.h file;
4570 Edit new board/<myboard> files
4571 Edit new include/configs/<myboard>.h
4576 Add / modify source code;
4580 email("Hi, I am having problems...");
4582 Send patch file to the U-Boot email list;
4583 if (reasonable critiques)
4584 Incorporate improvements from email list code review;
4586 Defend code as written;
4592 void no_more_time (int sig)
4601 All contributions to U-Boot should conform to the Linux kernel
4602 coding style; see the file "Documentation/CodingStyle" and the script
4603 "scripts/Lindent" in your Linux kernel source directory.
4605 Source files originating from a different project (for example the
4606 MTD subsystem) are generally exempt from these guidelines and are not
4607 reformated to ease subsequent migration to newer versions of those
4610 Please note that U-Boot is implemented in C (and to some small parts in
4611 Assembler); no C++ is used, so please do not use C++ style comments (//)
4614 Please also stick to the following formatting rules:
4615 - remove any trailing white space
4616 - use TAB characters for indentation and vertical alignment, not spaces
4617 - make sure NOT to use DOS '\r\n' line feeds
4618 - do not add more than 2 consecutive empty lines to source files
4619 - do not add trailing empty lines to source files
4621 Submissions which do not conform to the standards may be returned
4622 with a request to reformat the changes.
4628 Since the number of patches for U-Boot is growing, we need to
4629 establish some rules. Submissions which do not conform to these rules
4630 may be rejected, even when they contain important and valuable stuff.
4632 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4634 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4635 see http://lists.denx.de/mailman/listinfo/u-boot
4637 When you send a patch, please include the following information with
4640 * For bug fixes: a description of the bug and how your patch fixes
4641 this bug. Please try to include a way of demonstrating that the
4642 patch actually fixes something.
4644 * For new features: a description of the feature and your
4647 * A CHANGELOG entry as plaintext (separate from the patch)
4649 * For major contributions, your entry to the CREDITS file
4651 * When you add support for a new board, don't forget to add this
4652 board to the MAINTAINERS file, too.
4654 * If your patch adds new configuration options, don't forget to
4655 document these in the README file.
4657 * The patch itself. If you are using git (which is *strongly*
4658 recommended) you can easily generate the patch using the
4659 "git format-patch". If you then use "git send-email" to send it to
4660 the U-Boot mailing list, you will avoid most of the common problems
4661 with some other mail clients.
4663 If you cannot use git, use "diff -purN OLD NEW". If your version of
4664 diff does not support these options, then get the latest version of
4667 The current directory when running this command shall be the parent
4668 directory of the U-Boot source tree (i. e. please make sure that
4669 your patch includes sufficient directory information for the
4672 We prefer patches as plain text. MIME attachments are discouraged,
4673 and compressed attachments must not be used.
4675 * If one logical set of modifications affects or creates several
4676 files, all these changes shall be submitted in a SINGLE patch file.
4678 * Changesets that contain different, unrelated modifications shall be
4679 submitted as SEPARATE patches, one patch per changeset.
4684 * Before sending the patch, run the MAKEALL script on your patched
4685 source tree and make sure that no errors or warnings are reported
4686 for any of the boards.
4688 * Keep your modifications to the necessary minimum: A patch
4689 containing several unrelated changes or arbitrary reformats will be
4690 returned with a request to re-formatting / split it.
4692 * If you modify existing code, make sure that your new code does not
4693 add to the memory footprint of the code ;-) Small is beautiful!
4694 When adding new features, these should compile conditionally only
4695 (using #ifdef), and the resulting code with the new feature
4696 disabled must not need more memory than the old code without your
4699 * Remember that there is a size limit of 100 kB per message on the
4700 u-boot mailing list. Bigger patches will be moderated. If they are
4701 reasonable and not too big, they will be acknowledged. But patches
4702 bigger than the size limit should be avoided.
projects / u-boot / blob