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_TFTPPUT * TFTP put command (upload)
792 CONFIG_CMD_TIME * run command and report execution time
793 CONFIG_CMD_USB * USB support
794 CONFIG_CMD_CDP * Cisco Discover Protocol support
795 CONFIG_CMD_FSL * Microblaze FSL support
798 EXAMPLE: If you want all functions except of network
799 support you can write:
801 #include "config_cmd_all.h"
802 #undef CONFIG_CMD_NET
805 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
807 Note: Don't enable the "icache" and "dcache" commands
808 (configuration option CONFIG_CMD_CACHE) unless you know
809 what you (and your U-Boot users) are doing. Data
810 cache cannot be enabled on systems like the 8xx or
811 8260 (where accesses to the IMMR region must be
812 uncached), and it cannot be disabled on all other
813 systems where we (mis-) use the data cache to hold an
814 initial stack and some data.
817 XXX - this list needs to get updated!
821 If this variable is defined, it enables watchdog
822 support for the SoC. There must be support in the SoC
823 specific code for a watchdog. For the 8xx and 8260
824 CPUs, the SIU Watchdog feature is enabled in the SYPCR
825 register. When supported for a specific SoC is
826 available, then no further board specific code should
830 When using a watchdog circuitry external to the used
831 SoC, then define this variable and provide board
832 specific code for the "hw_watchdog_reset" function.
835 CONFIG_VERSION_VARIABLE
836 If this variable is defined, an environment variable
837 named "ver" is created by U-Boot showing the U-Boot
838 version as printed by the "version" command.
839 This variable is readonly.
843 When CONFIG_CMD_DATE is selected, the type of the RTC
844 has to be selected, too. Define exactly one of the
847 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
848 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
849 CONFIG_RTC_MC13783 - use MC13783 RTC
850 CONFIG_RTC_MC146818 - use MC146818 RTC
851 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
852 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
853 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
854 CONFIG_RTC_DS164x - use Dallas DS164x RTC
855 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
856 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
857 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
858 CONFIG_SYS_RV3029_TCR - enable trickle charger on
861 Note that if the RTC uses I2C, then the I2C interface
862 must also be configured. See I2C Support, below.
865 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
866 CONFIG_PCA953X_INFO - enable pca953x info command
868 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
869 chip-ngpio pairs that tell the PCA953X driver the number of
870 pins supported by a particular chip.
872 Note that if the GPIO device uses I2C, then the I2C interface
873 must also be configured. See I2C Support, below.
877 When CONFIG_TIMESTAMP is selected, the timestamp
878 (date and time) of an image is printed by image
879 commands like bootm or iminfo. This option is
880 automatically enabled when you select CONFIG_CMD_DATE .
883 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
884 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
886 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
887 CONFIG_CMD_SCSI) you must configure support for at
888 least one partition type as well.
891 CONFIG_IDE_RESET_ROUTINE - this is defined in several
892 board configurations files but used nowhere!
894 CONFIG_IDE_RESET - is this is defined, IDE Reset will
895 be performed by calling the function
896 ide_set_reset(int reset)
897 which has to be defined in a board specific file
902 Set this to enable ATAPI support.
907 Set this to enable support for disks larger than 137GB
908 Also look at CONFIG_SYS_64BIT_LBA.
909 Whithout these , LBA48 support uses 32bit variables and will 'only'
910 support disks up to 2.1TB.
912 CONFIG_SYS_64BIT_LBA:
913 When enabled, makes the IDE subsystem use 64bit sector addresses.
917 At the moment only there is only support for the
918 SYM53C8XX SCSI controller; define
919 CONFIG_SCSI_SYM53C8XX to enable it.
921 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
922 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
923 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
924 maximum numbers of LUNs, SCSI ID's and target
926 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
928 - NETWORK Support (PCI):
930 Support for Intel 8254x gigabit chips.
932 CONFIG_E1000_FALLBACK_MAC
933 default MAC for empty EEPROM after production.
936 Support for Intel 82557/82559/82559ER chips.
937 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
938 write routine for first time initialisation.
941 Support for Digital 2114x chips.
942 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
943 modem chip initialisation (KS8761/QS6611).
946 Support for National dp83815 chips.
949 Support for National dp8382[01] gigabit chips.
951 - NETWORK Support (other):
953 CONFIG_DRIVER_AT91EMAC
954 Support for AT91RM9200 EMAC.
957 Define this to use reduced MII inteface
959 CONFIG_DRIVER_AT91EMAC_QUIET
960 If this defined, the driver is quiet.
961 The driver doen't show link status messages.
963 CONFIG_DRIVER_LAN91C96
964 Support for SMSC's LAN91C96 chips.
967 Define this to hold the physical address
968 of the LAN91C96's I/O space
970 CONFIG_LAN91C96_USE_32_BIT
971 Define this to enable 32 bit addressing
973 CONFIG_DRIVER_SMC91111
974 Support for SMSC's LAN91C111 chip
977 Define this to hold the physical address
978 of the device (I/O space)
980 CONFIG_SMC_USE_32_BIT
981 Define this if data bus is 32 bits
983 CONFIG_SMC_USE_IOFUNCS
984 Define this to use i/o functions instead of macros
985 (some hardware wont work with macros)
988 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
990 CONFIG_FTGMAC100_EGIGA
991 Define this to use GE link update with gigabit PHY.
992 Define this if FTGMAC100 is connected to gigabit PHY.
993 If your system has 10/100 PHY only, it might not occur
994 wrong behavior. Because PHY usually return timeout or
995 useless data when polling gigabit status and gigabit
996 control registers. This behavior won't affect the
997 correctnessof 10/100 link speed update.
1000 Support for SMSC's LAN911x and LAN921x chips
1003 Define this to hold the physical address
1004 of the device (I/O space)
1006 CONFIG_SMC911X_32_BIT
1007 Define this if data bus is 32 bits
1009 CONFIG_SMC911X_16_BIT
1010 Define this if data bus is 16 bits. If your processor
1011 automatically converts one 32 bit word to two 16 bit
1012 words you may also try CONFIG_SMC911X_32_BIT.
1015 Support for Renesas on-chip Ethernet controller
1017 CONFIG_SH_ETHER_USE_PORT
1018 Define the number of ports to be used
1020 CONFIG_SH_ETHER_PHY_ADDR
1021 Define the ETH PHY's address
1023 CONFIG_SH_ETHER_CACHE_WRITEBACK
1024 If this option is set, the driver enables cache flush.
1027 At the moment only the UHCI host controller is
1028 supported (PIP405, MIP405, MPC5200); define
1029 CONFIG_USB_UHCI to enable it.
1030 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1031 and define CONFIG_USB_STORAGE to enable the USB
1034 Supported are USB Keyboards and USB Floppy drives
1036 MPC5200 USB requires additional defines:
1038 for 528 MHz Clock: 0x0001bbbb
1042 for differential drivers: 0x00001000
1043 for single ended drivers: 0x00005000
1044 for differential drivers on PSC3: 0x00000100
1045 for single ended drivers on PSC3: 0x00004100
1046 CONFIG_SYS_USB_EVENT_POLL
1047 May be defined to allow interrupt polling
1048 instead of using asynchronous interrupts
1051 Define the below if you wish to use the USB console.
1052 Once firmware is rebuilt from a serial console issue the
1053 command "setenv stdin usbtty; setenv stdout usbtty" and
1054 attach your USB cable. The Unix command "dmesg" should print
1055 it has found a new device. The environment variable usbtty
1056 can be set to gserial or cdc_acm to enable your device to
1057 appear to a USB host as a Linux gserial device or a
1058 Common Device Class Abstract Control Model serial device.
1059 If you select usbtty = gserial you should be able to enumerate
1061 # modprobe usbserial vendor=0xVendorID product=0xProductID
1062 else if using cdc_acm, simply setting the environment
1063 variable usbtty to be cdc_acm should suffice. The following
1064 might be defined in YourBoardName.h
1067 Define this to build a UDC device
1070 Define this to have a tty type of device available to
1071 talk to the UDC device
1073 CONFIG_SYS_CONSOLE_IS_IN_ENV
1074 Define this if you want stdin, stdout &/or stderr to
1078 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1079 Derive USB clock from external clock "blah"
1080 - CONFIG_SYS_USB_EXTC_CLK 0x02
1082 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1083 Derive USB clock from brgclk
1084 - CONFIG_SYS_USB_BRG_CLK 0x04
1086 If you have a USB-IF assigned VendorID then you may wish to
1087 define your own vendor specific values either in BoardName.h
1088 or directly in usbd_vendor_info.h. If you don't define
1089 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1090 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1091 should pretend to be a Linux device to it's target host.
1093 CONFIG_USBD_MANUFACTURER
1094 Define this string as the name of your company for
1095 - CONFIG_USBD_MANUFACTURER "my company"
1097 CONFIG_USBD_PRODUCT_NAME
1098 Define this string as the name of your product
1099 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1101 CONFIG_USBD_VENDORID
1102 Define this as your assigned Vendor ID from the USB
1103 Implementors Forum. This *must* be a genuine Vendor ID
1104 to avoid polluting the USB namespace.
1105 - CONFIG_USBD_VENDORID 0xFFFF
1107 CONFIG_USBD_PRODUCTID
1108 Define this as the unique Product ID
1110 - CONFIG_USBD_PRODUCTID 0xFFFF
1114 The MMC controller on the Intel PXA is supported. To
1115 enable this define CONFIG_MMC. The MMC can be
1116 accessed from the boot prompt by mapping the device
1117 to physical memory similar to flash. Command line is
1118 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1119 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1122 Support for Renesas on-chip MMCIF controller
1124 CONFIG_SH_MMCIF_ADDR
1125 Define the base address of MMCIF registers
1128 Define the clock frequency for MMCIF
1130 - Journaling Flash filesystem support:
1131 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1132 CONFIG_JFFS2_NAND_DEV
1133 Define these for a default partition on a NAND device
1135 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1136 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1137 Define these for a default partition on a NOR device
1139 CONFIG_SYS_JFFS_CUSTOM_PART
1140 Define this to create an own partition. You have to provide a
1141 function struct part_info* jffs2_part_info(int part_num)
1143 If you define only one JFFS2 partition you may also want to
1144 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1145 to disable the command chpart. This is the default when you
1146 have not defined a custom partition
1151 Define this to enable standard (PC-Style) keyboard
1155 Standard PC keyboard driver with US (is default) and
1156 GERMAN key layout (switch via environment 'keymap=de') support.
1157 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1158 for cfb_console. Supports cursor blinking.
1163 Define this to enable video support (for output to
1166 CONFIG_VIDEO_CT69000
1168 Enable Chips & Technologies 69000 Video chip
1170 CONFIG_VIDEO_SMI_LYNXEM
1171 Enable Silicon Motion SMI 712/710/810 Video chip. The
1172 video output is selected via environment 'videoout'
1173 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1176 For the CT69000 and SMI_LYNXEM drivers, videomode is
1177 selected via environment 'videomode'. Two different ways
1179 - "videomode=num" 'num' is a standard LiLo mode numbers.
1180 Following standard modes are supported (* is default):
1182 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1183 -------------+---------------------------------------------
1184 8 bits | 0x301* 0x303 0x305 0x161 0x307
1185 15 bits | 0x310 0x313 0x316 0x162 0x319
1186 16 bits | 0x311 0x314 0x317 0x163 0x31A
1187 24 bits | 0x312 0x315 0x318 ? 0x31B
1188 -------------+---------------------------------------------
1189 (i.e. setenv videomode 317; saveenv; reset;)
1191 - "videomode=bootargs" all the video parameters are parsed
1192 from the bootargs. (See drivers/video/videomodes.c)
1195 CONFIG_VIDEO_SED13806
1196 Enable Epson SED13806 driver. This driver supports 8bpp
1197 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1198 or CONFIG_VIDEO_SED13806_16BPP
1201 Enable the Freescale DIU video driver. Reference boards for
1202 SOCs that have a DIU should define this macro to enable DIU
1203 support, and should also define these other macros:
1209 CONFIG_VIDEO_SW_CURSOR
1210 CONFIG_VGA_AS_SINGLE_DEVICE
1212 CONFIG_VIDEO_BMP_LOGO
1214 The DIU driver will look for the 'video-mode' environment
1215 variable, and if defined, enable the DIU as a console during
1216 boot. See the documentation file README.video for a
1217 description of this variable.
1222 Define this to enable a custom keyboard support.
1223 This simply calls drv_keyboard_init() which must be
1224 defined in your board-specific files.
1225 The only board using this so far is RBC823.
1227 - LCD Support: CONFIG_LCD
1229 Define this to enable LCD support (for output to LCD
1230 display); also select one of the supported displays
1231 by defining one of these:
1235 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1237 CONFIG_NEC_NL6448AC33:
1239 NEC NL6448AC33-18. Active, color, single scan.
1241 CONFIG_NEC_NL6448BC20
1243 NEC NL6448BC20-08. 6.5", 640x480.
1244 Active, color, single scan.
1246 CONFIG_NEC_NL6448BC33_54
1248 NEC NL6448BC33-54. 10.4", 640x480.
1249 Active, color, single scan.
1253 Sharp 320x240. Active, color, single scan.
1254 It isn't 16x9, and I am not sure what it is.
1256 CONFIG_SHARP_LQ64D341
1258 Sharp LQ64D341 display, 640x480.
1259 Active, color, single scan.
1263 HLD1045 display, 640x480.
1264 Active, color, single scan.
1268 Optrex CBL50840-2 NF-FW 99 22 M5
1270 Hitachi LMG6912RPFC-00T
1274 320x240. Black & white.
1276 Normally display is black on white background; define
1277 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1279 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1281 If this option is set, the environment is checked for
1282 a variable "splashimage". If found, the usual display
1283 of logo, copyright and system information on the LCD
1284 is suppressed and the BMP image at the address
1285 specified in "splashimage" is loaded instead. The
1286 console is redirected to the "nulldev", too. This
1287 allows for a "silent" boot where a splash screen is
1288 loaded very quickly after power-on.
1290 CONFIG_SPLASH_SCREEN_ALIGN
1292 If this option is set the splash image can be freely positioned
1293 on the screen. Environment variable "splashpos" specifies the
1294 position as "x,y". If a positive number is given it is used as
1295 number of pixel from left/top. If a negative number is given it
1296 is used as number of pixel from right/bottom. You can also
1297 specify 'm' for centering the image.
1300 setenv splashpos m,m
1301 => image at center of screen
1303 setenv splashpos 30,20
1304 => image at x = 30 and y = 20
1306 setenv splashpos -10,m
1307 => vertically centered image
1308 at x = dspWidth - bmpWidth - 9
1310 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1312 If this option is set, additionally to standard BMP
1313 images, gzipped BMP images can be displayed via the
1314 splashscreen support or the bmp command.
1316 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1318 If this option is set, 8-bit RLE compressed BMP images
1319 can be displayed via the splashscreen support or the
1322 - Compression support:
1325 If this option is set, support for bzip2 compressed
1326 images is included. If not, only uncompressed and gzip
1327 compressed images are supported.
1329 NOTE: the bzip2 algorithm requires a lot of RAM, so
1330 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1335 If this option is set, support for lzma compressed
1338 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1339 requires an amount of dynamic memory that is given by the
1342 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1344 Where lc and lp stand for, respectively, Literal context bits
1345 and Literal pos bits.
1347 This value is upper-bounded by 14MB in the worst case. Anyway,
1348 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1349 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1350 a very small buffer.
1352 Use the lzmainfo tool to determinate the lc and lp values and
1353 then calculate the amount of needed dynamic memory (ensuring
1354 the appropriate CONFIG_SYS_MALLOC_LEN value).
1359 The address of PHY on MII bus.
1361 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1363 The clock frequency of the MII bus
1367 If this option is set, support for speed/duplex
1368 detection of gigabit PHY is included.
1370 CONFIG_PHY_RESET_DELAY
1372 Some PHY like Intel LXT971A need extra delay after
1373 reset before any MII register access is possible.
1374 For such PHY, set this option to the usec delay
1375 required. (minimum 300usec for LXT971A)
1377 CONFIG_PHY_CMD_DELAY (ppc4xx)
1379 Some PHY like Intel LXT971A need extra delay after
1380 command issued before MII status register can be read
1390 Define a default value for Ethernet address to use
1391 for the respective Ethernet interface, in case this
1392 is not determined automatically.
1397 Define a default value for the IP address to use for
1398 the default Ethernet interface, in case this is not
1399 determined through e.g. bootp.
1401 - Server IP address:
1404 Defines a default value for the IP address of a TFTP
1405 server to contact when using the "tftboot" command.
1407 CONFIG_KEEP_SERVERADDR
1409 Keeps the server's MAC address, in the env 'serveraddr'
1410 for passing to bootargs (like Linux's netconsole option)
1412 - Multicast TFTP Mode:
1415 Defines whether you want to support multicast TFTP as per
1416 rfc-2090; for example to work with atftp. Lets lots of targets
1417 tftp down the same boot image concurrently. Note: the Ethernet
1418 driver in use must provide a function: mcast() to join/leave a
1421 - BOOTP Recovery Mode:
1422 CONFIG_BOOTP_RANDOM_DELAY
1424 If you have many targets in a network that try to
1425 boot using BOOTP, you may want to avoid that all
1426 systems send out BOOTP requests at precisely the same
1427 moment (which would happen for instance at recovery
1428 from a power failure, when all systems will try to
1429 boot, thus flooding the BOOTP server. Defining
1430 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1431 inserted before sending out BOOTP requests. The
1432 following delays are inserted then:
1434 1st BOOTP request: delay 0 ... 1 sec
1435 2nd BOOTP request: delay 0 ... 2 sec
1436 3rd BOOTP request: delay 0 ... 4 sec
1438 BOOTP requests: delay 0 ... 8 sec
1440 - DHCP Advanced Options:
1441 You can fine tune the DHCP functionality by defining
1442 CONFIG_BOOTP_* symbols:
1444 CONFIG_BOOTP_SUBNETMASK
1445 CONFIG_BOOTP_GATEWAY
1446 CONFIG_BOOTP_HOSTNAME
1447 CONFIG_BOOTP_NISDOMAIN
1448 CONFIG_BOOTP_BOOTPATH
1449 CONFIG_BOOTP_BOOTFILESIZE
1452 CONFIG_BOOTP_SEND_HOSTNAME
1453 CONFIG_BOOTP_NTPSERVER
1454 CONFIG_BOOTP_TIMEOFFSET
1455 CONFIG_BOOTP_VENDOREX
1457 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1458 environment variable, not the BOOTP server.
1460 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1461 serverip from a DHCP server, it is possible that more
1462 than one DNS serverip is offered to the client.
1463 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1464 serverip will be stored in the additional environment
1465 variable "dnsip2". The first DNS serverip is always
1466 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1469 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1470 to do a dynamic update of a DNS server. To do this, they
1471 need the hostname of the DHCP requester.
1472 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1473 of the "hostname" environment variable is passed as
1474 option 12 to the DHCP server.
1476 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1478 A 32bit value in microseconds for a delay between
1479 receiving a "DHCP Offer" and sending the "DHCP Request".
1480 This fixes a problem with certain DHCP servers that don't
1481 respond 100% of the time to a "DHCP request". E.g. On an
1482 AT91RM9200 processor running at 180MHz, this delay needed
1483 to be *at least* 15,000 usec before a Windows Server 2003
1484 DHCP server would reply 100% of the time. I recommend at
1485 least 50,000 usec to be safe. The alternative is to hope
1486 that one of the retries will be successful but note that
1487 the DHCP timeout and retry process takes a longer than
1491 CONFIG_CDP_DEVICE_ID
1493 The device id used in CDP trigger frames.
1495 CONFIG_CDP_DEVICE_ID_PREFIX
1497 A two character string which is prefixed to the MAC address
1502 A printf format string which contains the ascii name of
1503 the port. Normally is set to "eth%d" which sets
1504 eth0 for the first Ethernet, eth1 for the second etc.
1506 CONFIG_CDP_CAPABILITIES
1508 A 32bit integer which indicates the device capabilities;
1509 0x00000010 for a normal host which does not forwards.
1513 An ascii string containing the version of the software.
1517 An ascii string containing the name of the platform.
1521 A 32bit integer sent on the trigger.
1523 CONFIG_CDP_POWER_CONSUMPTION
1525 A 16bit integer containing the power consumption of the
1526 device in .1 of milliwatts.
1528 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1530 A byte containing the id of the VLAN.
1532 - Status LED: CONFIG_STATUS_LED
1534 Several configurations allow to display the current
1535 status using a LED. For instance, the LED will blink
1536 fast while running U-Boot code, stop blinking as
1537 soon as a reply to a BOOTP request was received, and
1538 start blinking slow once the Linux kernel is running
1539 (supported by a status LED driver in the Linux
1540 kernel). Defining CONFIG_STATUS_LED enables this
1543 - CAN Support: CONFIG_CAN_DRIVER
1545 Defining CONFIG_CAN_DRIVER enables CAN driver support
1546 on those systems that support this (optional)
1547 feature, like the TQM8xxL modules.
1549 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1551 These enable I2C serial bus commands. Defining either of
1552 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1553 include the appropriate I2C driver for the selected CPU.
1555 This will allow you to use i2c commands at the u-boot
1556 command line (as long as you set CONFIG_CMD_I2C in
1557 CONFIG_COMMANDS) and communicate with i2c based realtime
1558 clock chips. See common/cmd_i2c.c for a description of the
1559 command line interface.
1561 CONFIG_HARD_I2C selects a hardware I2C controller.
1563 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1564 bit-banging) driver instead of CPM or similar hardware
1567 There are several other quantities that must also be
1568 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1570 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1571 to be the frequency (in Hz) at which you wish your i2c bus
1572 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1573 the CPU's i2c node address).
1575 Now, the u-boot i2c code for the mpc8xx
1576 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1577 and so its address should therefore be cleared to 0 (See,
1578 eg, MPC823e User's Manual p.16-473). So, set
1579 CONFIG_SYS_I2C_SLAVE to 0.
1581 CONFIG_SYS_I2C_INIT_MPC5XXX
1583 When a board is reset during an i2c bus transfer
1584 chips might think that the current transfer is still
1585 in progress. Reset the slave devices by sending start
1586 commands until the slave device responds.
1588 That's all that's required for CONFIG_HARD_I2C.
1590 If you use the software i2c interface (CONFIG_SOFT_I2C)
1591 then the following macros need to be defined (examples are
1592 from include/configs/lwmon.h):
1596 (Optional). Any commands necessary to enable the I2C
1597 controller or configure ports.
1599 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1603 (Only for MPC8260 CPU). The I/O port to use (the code
1604 assumes both bits are on the same port). Valid values
1605 are 0..3 for ports A..D.
1609 The code necessary to make the I2C data line active
1610 (driven). If the data line is open collector, this
1613 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1617 The code necessary to make the I2C data line tri-stated
1618 (inactive). If the data line is open collector, this
1621 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1625 Code that returns TRUE if the I2C data line is high,
1628 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1632 If <bit> is TRUE, sets the I2C data line high. If it
1633 is FALSE, it clears it (low).
1635 eg: #define I2C_SDA(bit) \
1636 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1637 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1641 If <bit> is TRUE, sets the I2C clock line high. If it
1642 is FALSE, it clears it (low).
1644 eg: #define I2C_SCL(bit) \
1645 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1646 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1650 This delay is invoked four times per clock cycle so this
1651 controls the rate of data transfer. The data rate thus
1652 is 1 / (I2C_DELAY * 4). Often defined to be something
1655 #define I2C_DELAY udelay(2)
1657 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1659 If your arch supports the generic GPIO framework (asm/gpio.h),
1660 then you may alternatively define the two GPIOs that are to be
1661 used as SCL / SDA. Any of the previous I2C_xxx macros will
1662 have GPIO-based defaults assigned to them as appropriate.
1664 You should define these to the GPIO value as given directly to
1665 the generic GPIO functions.
1667 CONFIG_SYS_I2C_INIT_BOARD
1669 When a board is reset during an i2c bus transfer
1670 chips might think that the current transfer is still
1671 in progress. On some boards it is possible to access
1672 the i2c SCLK line directly, either by using the
1673 processor pin as a GPIO or by having a second pin
1674 connected to the bus. If this option is defined a
1675 custom i2c_init_board() routine in boards/xxx/board.c
1676 is run early in the boot sequence.
1678 CONFIG_SYS_I2C_BOARD_LATE_INIT
1680 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1681 defined a custom i2c_board_late_init() routine in
1682 boards/xxx/board.c is run AFTER the operations in i2c_init()
1683 is completed. This callpoint can be used to unreset i2c bus
1684 using CPU i2c controller register accesses for CPUs whose i2c
1685 controller provide such a method. It is called at the end of
1686 i2c_init() to allow i2c_init operations to setup the i2c bus
1687 controller on the CPU (e.g. setting bus speed & slave address).
1689 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1691 This option enables configuration of bi_iic_fast[] flags
1692 in u-boot bd_info structure based on u-boot environment
1693 variable "i2cfast". (see also i2cfast)
1695 CONFIG_I2C_MULTI_BUS
1697 This option allows the use of multiple I2C buses, each of which
1698 must have a controller. At any point in time, only one bus is
1699 active. To switch to a different bus, use the 'i2c dev' command.
1700 Note that bus numbering is zero-based.
1702 CONFIG_SYS_I2C_NOPROBES
1704 This option specifies a list of I2C devices that will be skipped
1705 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1706 is set, specify a list of bus-device pairs. Otherwise, specify
1707 a 1D array of device addresses
1710 #undef CONFIG_I2C_MULTI_BUS
1711 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1713 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1715 #define CONFIG_I2C_MULTI_BUS
1716 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1718 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1720 CONFIG_SYS_SPD_BUS_NUM
1722 If defined, then this indicates the I2C bus number for DDR SPD.
1723 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1725 CONFIG_SYS_RTC_BUS_NUM
1727 If defined, then this indicates the I2C bus number for the RTC.
1728 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1730 CONFIG_SYS_DTT_BUS_NUM
1732 If defined, then this indicates the I2C bus number for the DTT.
1733 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1735 CONFIG_SYS_I2C_DTT_ADDR:
1737 If defined, specifies the I2C address of the DTT device.
1738 If not defined, then U-Boot uses predefined value for
1739 specified DTT device.
1743 Define this option if you want to use Freescale's I2C driver in
1744 drivers/i2c/fsl_i2c.c.
1748 Define this option if you have I2C devices reached over 1 .. n
1749 I2C Muxes like the pca9544a. This option addes a new I2C
1750 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1751 new I2C Bus to the existing I2C Busses. If you select the
1752 new Bus with "i2c dev", u-bbot sends first the commandos for
1753 the muxes to activate this new "bus".
1755 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1759 Adding a new I2C Bus reached over 2 pca9544a muxes
1760 The First mux with address 70 and channel 6
1761 The Second mux with address 71 and channel 4
1763 => i2c bus pca9544a:70:6:pca9544a:71:4
1765 Use the "i2c bus" command without parameter, to get a list
1766 of I2C Busses with muxes:
1769 Busses reached over muxes:
1771 reached over Mux(es):
1774 reached over Mux(es):
1779 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1780 u-boot first sends the command to the mux@70 to enable
1781 channel 6, and then the command to the mux@71 to enable
1784 After that, you can use the "normal" i2c commands as
1785 usual to communicate with your I2C devices behind
1788 This option is actually implemented for the bitbanging
1789 algorithm in common/soft_i2c.c and for the Hardware I2C
1790 Bus on the MPC8260. But it should be not so difficult
1791 to add this option to other architectures.
1793 CONFIG_SOFT_I2C_READ_REPEATED_START
1795 defining this will force the i2c_read() function in
1796 the soft_i2c driver to perform an I2C repeated start
1797 between writing the address pointer and reading the
1798 data. If this define is omitted the default behaviour
1799 of doing a stop-start sequence will be used. Most I2C
1800 devices can use either method, but some require one or
1803 - SPI Support: CONFIG_SPI
1805 Enables SPI driver (so far only tested with
1806 SPI EEPROM, also an instance works with Crystal A/D and
1807 D/As on the SACSng board)
1811 Enables the driver for SPI controller on SuperH. Currently
1812 only SH7757 is supported.
1816 Enables extended (16-bit) SPI EEPROM addressing.
1817 (symmetrical to CONFIG_I2C_X)
1821 Enables a software (bit-bang) SPI driver rather than
1822 using hardware support. This is a general purpose
1823 driver that only requires three general I/O port pins
1824 (two outputs, one input) to function. If this is
1825 defined, the board configuration must define several
1826 SPI configuration items (port pins to use, etc). For
1827 an example, see include/configs/sacsng.h.
1831 Enables a hardware SPI driver for general-purpose reads
1832 and writes. As with CONFIG_SOFT_SPI, the board configuration
1833 must define a list of chip-select function pointers.
1834 Currently supported on some MPC8xxx processors. For an
1835 example, see include/configs/mpc8349emds.h.
1839 Enables the driver for the SPI controllers on i.MX and MXC
1840 SoCs. Currently only i.MX31 is supported.
1842 - FPGA Support: CONFIG_FPGA
1844 Enables FPGA subsystem.
1846 CONFIG_FPGA_<vendor>
1848 Enables support for specific chip vendors.
1851 CONFIG_FPGA_<family>
1853 Enables support for FPGA family.
1854 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1858 Specify the number of FPGA devices to support.
1860 CONFIG_SYS_FPGA_PROG_FEEDBACK
1862 Enable printing of hash marks during FPGA configuration.
1864 CONFIG_SYS_FPGA_CHECK_BUSY
1866 Enable checks on FPGA configuration interface busy
1867 status by the configuration function. This option
1868 will require a board or device specific function to
1873 If defined, a function that provides delays in the FPGA
1874 configuration driver.
1876 CONFIG_SYS_FPGA_CHECK_CTRLC
1877 Allow Control-C to interrupt FPGA configuration
1879 CONFIG_SYS_FPGA_CHECK_ERROR
1881 Check for configuration errors during FPGA bitfile
1882 loading. For example, abort during Virtex II
1883 configuration if the INIT_B line goes low (which
1884 indicated a CRC error).
1886 CONFIG_SYS_FPGA_WAIT_INIT
1888 Maximum time to wait for the INIT_B line to deassert
1889 after PROB_B has been deasserted during a Virtex II
1890 FPGA configuration sequence. The default time is 500
1893 CONFIG_SYS_FPGA_WAIT_BUSY
1895 Maximum time to wait for BUSY to deassert during
1896 Virtex II FPGA configuration. The default is 5 ms.
1898 CONFIG_SYS_FPGA_WAIT_CONFIG
1900 Time to wait after FPGA configuration. The default is
1903 - Configuration Management:
1906 If defined, this string will be added to the U-Boot
1907 version information (U_BOOT_VERSION)
1909 - Vendor Parameter Protection:
1911 U-Boot considers the values of the environment
1912 variables "serial#" (Board Serial Number) and
1913 "ethaddr" (Ethernet Address) to be parameters that
1914 are set once by the board vendor / manufacturer, and
1915 protects these variables from casual modification by
1916 the user. Once set, these variables are read-only,
1917 and write or delete attempts are rejected. You can
1918 change this behaviour:
1920 If CONFIG_ENV_OVERWRITE is #defined in your config
1921 file, the write protection for vendor parameters is
1922 completely disabled. Anybody can change or delete
1925 Alternatively, if you #define _both_ CONFIG_ETHADDR
1926 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1927 Ethernet address is installed in the environment,
1928 which can be changed exactly ONCE by the user. [The
1929 serial# is unaffected by this, i. e. it remains
1935 Define this variable to enable the reservation of
1936 "protected RAM", i. e. RAM which is not overwritten
1937 by U-Boot. Define CONFIG_PRAM to hold the number of
1938 kB you want to reserve for pRAM. You can overwrite
1939 this default value by defining an environment
1940 variable "pram" to the number of kB you want to
1941 reserve. Note that the board info structure will
1942 still show the full amount of RAM. If pRAM is
1943 reserved, a new environment variable "mem" will
1944 automatically be defined to hold the amount of
1945 remaining RAM in a form that can be passed as boot
1946 argument to Linux, for instance like that:
1948 setenv bootargs ... mem=\${mem}
1951 This way you can tell Linux not to use this memory,
1952 either, which results in a memory region that will
1953 not be affected by reboots.
1955 *WARNING* If your board configuration uses automatic
1956 detection of the RAM size, you must make sure that
1957 this memory test is non-destructive. So far, the
1958 following board configurations are known to be
1961 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1962 HERMES, IP860, RPXlite, LWMON, LANTEC,
1968 Define this variable to stop the system in case of a
1969 fatal error, so that you have to reset it manually.
1970 This is probably NOT a good idea for an embedded
1971 system where you want the system to reboot
1972 automatically as fast as possible, but it may be
1973 useful during development since you can try to debug
1974 the conditions that lead to the situation.
1976 CONFIG_NET_RETRY_COUNT
1978 This variable defines the number of retries for
1979 network operations like ARP, RARP, TFTP, or BOOTP
1980 before giving up the operation. If not defined, a
1981 default value of 5 is used.
1985 Timeout waiting for an ARP reply in milliseconds.
1987 - Command Interpreter:
1988 CONFIG_AUTO_COMPLETE
1990 Enable auto completion of commands using TAB.
1992 Note that this feature has NOT been implemented yet
1993 for the "hush" shell.
1996 CONFIG_SYS_HUSH_PARSER
1998 Define this variable to enable the "hush" shell (from
1999 Busybox) as command line interpreter, thus enabling
2000 powerful command line syntax like
2001 if...then...else...fi conditionals or `&&' and '||'
2002 constructs ("shell scripts").
2004 If undefined, you get the old, much simpler behaviour
2005 with a somewhat smaller memory footprint.
2008 CONFIG_SYS_PROMPT_HUSH_PS2
2010 This defines the secondary prompt string, which is
2011 printed when the command interpreter needs more input
2012 to complete a command. Usually "> ".
2016 In the current implementation, the local variables
2017 space and global environment variables space are
2018 separated. Local variables are those you define by
2019 simply typing `name=value'. To access a local
2020 variable later on, you have write `$name' or
2021 `${name}'; to execute the contents of a variable
2022 directly type `$name' at the command prompt.
2024 Global environment variables are those you use
2025 setenv/printenv to work with. To run a command stored
2026 in such a variable, you need to use the run command,
2027 and you must not use the '$' sign to access them.
2029 To store commands and special characters in a
2030 variable, please use double quotation marks
2031 surrounding the whole text of the variable, instead
2032 of the backslashes before semicolons and special
2035 - Commandline Editing and History:
2036 CONFIG_CMDLINE_EDITING
2038 Enable editing and History functions for interactive
2039 commandline input operations
2041 - Default Environment:
2042 CONFIG_EXTRA_ENV_SETTINGS
2044 Define this to contain any number of null terminated
2045 strings (variable = value pairs) that will be part of
2046 the default environment compiled into the boot image.
2048 For example, place something like this in your
2049 board's config file:
2051 #define CONFIG_EXTRA_ENV_SETTINGS \
2055 Warning: This method is based on knowledge about the
2056 internal format how the environment is stored by the
2057 U-Boot code. This is NOT an official, exported
2058 interface! Although it is unlikely that this format
2059 will change soon, there is no guarantee either.
2060 You better know what you are doing here.
2062 Note: overly (ab)use of the default environment is
2063 discouraged. Make sure to check other ways to preset
2064 the environment like the "source" command or the
2067 - DataFlash Support:
2068 CONFIG_HAS_DATAFLASH
2070 Defining this option enables DataFlash features and
2071 allows to read/write in Dataflash via the standard
2074 - SystemACE Support:
2077 Adding this option adds support for Xilinx SystemACE
2078 chips attached via some sort of local bus. The address
2079 of the chip must also be defined in the
2080 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2082 #define CONFIG_SYSTEMACE
2083 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2085 When SystemACE support is added, the "ace" device type
2086 becomes available to the fat commands, i.e. fatls.
2088 - TFTP Fixed UDP Port:
2091 If this is defined, the environment variable tftpsrcp
2092 is used to supply the TFTP UDP source port value.
2093 If tftpsrcp isn't defined, the normal pseudo-random port
2094 number generator is used.
2096 Also, the environment variable tftpdstp is used to supply
2097 the TFTP UDP destination port value. If tftpdstp isn't
2098 defined, the normal port 69 is used.
2100 The purpose for tftpsrcp is to allow a TFTP server to
2101 blindly start the TFTP transfer using the pre-configured
2102 target IP address and UDP port. This has the effect of
2103 "punching through" the (Windows XP) firewall, allowing
2104 the remainder of the TFTP transfer to proceed normally.
2105 A better solution is to properly configure the firewall,
2106 but sometimes that is not allowed.
2108 - Show boot progress:
2109 CONFIG_SHOW_BOOT_PROGRESS
2111 Defining this option allows to add some board-
2112 specific code (calling a user-provided function
2113 "show_boot_progress(int)") that enables you to show
2114 the system's boot progress on some display (for
2115 example, some LED's) on your board. At the moment,
2116 the following checkpoints are implemented:
2118 Legacy uImage format:
2121 1 common/cmd_bootm.c before attempting to boot an image
2122 -1 common/cmd_bootm.c Image header has bad magic number
2123 2 common/cmd_bootm.c Image header has correct magic number
2124 -2 common/cmd_bootm.c Image header has bad checksum
2125 3 common/cmd_bootm.c Image header has correct checksum
2126 -3 common/cmd_bootm.c Image data has bad checksum
2127 4 common/cmd_bootm.c Image data has correct checksum
2128 -4 common/cmd_bootm.c Image is for unsupported architecture
2129 5 common/cmd_bootm.c Architecture check OK
2130 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2131 6 common/cmd_bootm.c Image Type check OK
2132 -6 common/cmd_bootm.c gunzip uncompression error
2133 -7 common/cmd_bootm.c Unimplemented compression type
2134 7 common/cmd_bootm.c Uncompression OK
2135 8 common/cmd_bootm.c No uncompress/copy overwrite error
2136 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2138 9 common/image.c Start initial ramdisk verification
2139 -10 common/image.c Ramdisk header has bad magic number
2140 -11 common/image.c Ramdisk header has bad checksum
2141 10 common/image.c Ramdisk header is OK
2142 -12 common/image.c Ramdisk data has bad checksum
2143 11 common/image.c Ramdisk data has correct checksum
2144 12 common/image.c Ramdisk verification complete, start loading
2145 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2146 13 common/image.c Start multifile image verification
2147 14 common/image.c No initial ramdisk, no multifile, continue.
2149 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2151 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2152 -31 post/post.c POST test failed, detected by post_output_backlog()
2153 -32 post/post.c POST test failed, detected by post_run_single()
2155 34 common/cmd_doc.c before loading a Image from a DOC device
2156 -35 common/cmd_doc.c Bad usage of "doc" command
2157 35 common/cmd_doc.c correct usage of "doc" command
2158 -36 common/cmd_doc.c No boot device
2159 36 common/cmd_doc.c correct boot device
2160 -37 common/cmd_doc.c Unknown Chip ID on boot device
2161 37 common/cmd_doc.c correct chip ID found, device available
2162 -38 common/cmd_doc.c Read Error on boot device
2163 38 common/cmd_doc.c reading Image header from DOC device OK
2164 -39 common/cmd_doc.c Image header has bad magic number
2165 39 common/cmd_doc.c Image header has correct magic number
2166 -40 common/cmd_doc.c Error reading Image from DOC device
2167 40 common/cmd_doc.c Image header has correct magic number
2168 41 common/cmd_ide.c before loading a Image from a IDE device
2169 -42 common/cmd_ide.c Bad usage of "ide" command
2170 42 common/cmd_ide.c correct usage of "ide" command
2171 -43 common/cmd_ide.c No boot device
2172 43 common/cmd_ide.c boot device found
2173 -44 common/cmd_ide.c Device not available
2174 44 common/cmd_ide.c Device available
2175 -45 common/cmd_ide.c wrong partition selected
2176 45 common/cmd_ide.c partition selected
2177 -46 common/cmd_ide.c Unknown partition table
2178 46 common/cmd_ide.c valid partition table found
2179 -47 common/cmd_ide.c Invalid partition type
2180 47 common/cmd_ide.c correct partition type
2181 -48 common/cmd_ide.c Error reading Image Header on boot device
2182 48 common/cmd_ide.c reading Image Header from IDE device OK
2183 -49 common/cmd_ide.c Image header has bad magic number
2184 49 common/cmd_ide.c Image header has correct magic number
2185 -50 common/cmd_ide.c Image header has bad checksum
2186 50 common/cmd_ide.c Image header has correct checksum
2187 -51 common/cmd_ide.c Error reading Image from IDE device
2188 51 common/cmd_ide.c reading Image from IDE device OK
2189 52 common/cmd_nand.c before loading a Image from a NAND device
2190 -53 common/cmd_nand.c Bad usage of "nand" command
2191 53 common/cmd_nand.c correct usage of "nand" command
2192 -54 common/cmd_nand.c No boot device
2193 54 common/cmd_nand.c boot device found
2194 -55 common/cmd_nand.c Unknown Chip ID on boot device
2195 55 common/cmd_nand.c correct chip ID found, device available
2196 -56 common/cmd_nand.c Error reading Image Header on boot device
2197 56 common/cmd_nand.c reading Image Header from NAND device OK
2198 -57 common/cmd_nand.c Image header has bad magic number
2199 57 common/cmd_nand.c Image header has correct magic number
2200 -58 common/cmd_nand.c Error reading Image from NAND device
2201 58 common/cmd_nand.c reading Image from NAND device OK
2203 -60 common/env_common.c Environment has a bad CRC, using default
2205 64 net/eth.c starting with Ethernet configuration.
2206 -64 net/eth.c no Ethernet found.
2207 65 net/eth.c Ethernet found.
2209 -80 common/cmd_net.c usage wrong
2210 80 common/cmd_net.c before calling NetLoop()
2211 -81 common/cmd_net.c some error in NetLoop() occurred
2212 81 common/cmd_net.c NetLoop() back without error
2213 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2214 82 common/cmd_net.c trying automatic boot
2215 83 common/cmd_net.c running "source" command
2216 -83 common/cmd_net.c some error in automatic boot or "source" command
2217 84 common/cmd_net.c end without errors
2222 100 common/cmd_bootm.c Kernel FIT Image has correct format
2223 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2224 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2225 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2226 102 common/cmd_bootm.c Kernel unit name specified
2227 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2228 103 common/cmd_bootm.c Found configuration node
2229 104 common/cmd_bootm.c Got kernel subimage node offset
2230 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2231 105 common/cmd_bootm.c Kernel subimage hash verification OK
2232 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2233 106 common/cmd_bootm.c Architecture check OK
2234 -106 common/cmd_bootm.c Kernel subimage has wrong type
2235 107 common/cmd_bootm.c Kernel subimage type OK
2236 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2237 108 common/cmd_bootm.c Got kernel subimage data/size
2238 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2239 -109 common/cmd_bootm.c Can't get kernel subimage type
2240 -110 common/cmd_bootm.c Can't get kernel subimage comp
2241 -111 common/cmd_bootm.c Can't get kernel subimage os
2242 -112 common/cmd_bootm.c Can't get kernel subimage load address
2243 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2245 120 common/image.c Start initial ramdisk verification
2246 -120 common/image.c Ramdisk FIT image has incorrect format
2247 121 common/image.c Ramdisk FIT image has correct format
2248 122 common/image.c No ramdisk subimage unit name, using configuration
2249 -122 common/image.c Can't get configuration for ramdisk subimage
2250 123 common/image.c Ramdisk unit name specified
2251 -124 common/image.c Can't get ramdisk subimage node offset
2252 125 common/image.c Got ramdisk subimage node offset
2253 -125 common/image.c Ramdisk subimage hash verification failed
2254 126 common/image.c Ramdisk subimage hash verification OK
2255 -126 common/image.c Ramdisk subimage for unsupported architecture
2256 127 common/image.c Architecture check OK
2257 -127 common/image.c Can't get ramdisk subimage data/size
2258 128 common/image.c Got ramdisk subimage data/size
2259 129 common/image.c Can't get ramdisk load address
2260 -129 common/image.c Got ramdisk load address
2262 -130 common/cmd_doc.c Incorrect FIT image format
2263 131 common/cmd_doc.c FIT image format OK
2265 -140 common/cmd_ide.c Incorrect FIT image format
2266 141 common/cmd_ide.c FIT image format OK
2268 -150 common/cmd_nand.c Incorrect FIT image format
2269 151 common/cmd_nand.c FIT image format OK
2271 - Standalone program support:
2272 CONFIG_STANDALONE_LOAD_ADDR
2274 This option defines a board specific value for the
2275 address where standalone program gets loaded, thus
2276 overwriting the architecture dependent default
2279 - Frame Buffer Address:
2282 Define CONFIG_FB_ADDR if you want to use specific
2283 address for frame buffer.
2284 Then system will reserve the frame buffer address to
2285 defined address instead of lcd_setmem (this function
2286 grabs the memory for frame buffer by panel's size).
2288 Please see board_init_f function.
2290 - Automatic software updates via TFTP server
2292 CONFIG_UPDATE_TFTP_CNT_MAX
2293 CONFIG_UPDATE_TFTP_MSEC_MAX
2295 These options enable and control the auto-update feature;
2296 for a more detailed description refer to doc/README.update.
2298 - MTD Support (mtdparts command, UBI support)
2301 Adds the MTD device infrastructure from the Linux kernel.
2302 Needed for mtdparts command support.
2304 CONFIG_MTD_PARTITIONS
2306 Adds the MTD partitioning infrastructure from the Linux
2307 kernel. Needed for UBI support.
2311 Enable building of SPL globally.
2313 CONFIG_SPL_TEXT_BASE
2314 TEXT_BASE for linking the SPL binary.
2317 LDSCRIPT for linking the SPL binary.
2319 CONFIG_SPL_LIBCOMMON_SUPPORT
2320 Support for common/libcommon.o in SPL binary
2322 CONFIG_SPL_LIBDISK_SUPPORT
2323 Support for disk/libdisk.o in SPL binary
2325 CONFIG_SPL_I2C_SUPPORT
2326 Support for drivers/i2c/libi2c.o in SPL binary
2328 CONFIG_SPL_GPIO_SUPPORT
2329 Support for drivers/gpio/libgpio.o in SPL binary
2331 CONFIG_SPL_MMC_SUPPORT
2332 Support for drivers/mmc/libmmc.o in SPL binary
2334 CONFIG_SPL_SERIAL_SUPPORT
2335 Support for drivers/serial/libserial.o in SPL binary
2337 CONFIG_SPL_SPI_FLASH_SUPPORT
2338 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2340 CONFIG_SPL_SPI_SUPPORT
2341 Support for drivers/spi/libspi.o in SPL binary
2343 CONFIG_SPL_FAT_SUPPORT
2344 Support for fs/fat/libfat.o in SPL binary
2346 CONFIG_SPL_LIBGENERIC_SUPPORT
2347 Support for lib/libgeneric.o in SPL binary
2352 [so far only for SMDK2400 boards]
2354 - Modem support enable:
2355 CONFIG_MODEM_SUPPORT
2357 - RTS/CTS Flow control enable:
2360 - Modem debug support:
2361 CONFIG_MODEM_SUPPORT_DEBUG
2363 Enables debugging stuff (char screen[1024], dbg())
2364 for modem support. Useful only with BDI2000.
2366 - Interrupt support (PPC):
2368 There are common interrupt_init() and timer_interrupt()
2369 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2370 for CPU specific initialization. interrupt_init_cpu()
2371 should set decrementer_count to appropriate value. If
2372 CPU resets decrementer automatically after interrupt
2373 (ppc4xx) it should set decrementer_count to zero.
2374 timer_interrupt() calls timer_interrupt_cpu() for CPU
2375 specific handling. If board has watchdog / status_led
2376 / other_activity_monitor it works automatically from
2377 general timer_interrupt().
2381 In the target system modem support is enabled when a
2382 specific key (key combination) is pressed during
2383 power-on. Otherwise U-Boot will boot normally
2384 (autoboot). The key_pressed() function is called from
2385 board_init(). Currently key_pressed() is a dummy
2386 function, returning 1 and thus enabling modem
2389 If there are no modem init strings in the
2390 environment, U-Boot proceed to autoboot; the
2391 previous output (banner, info printfs) will be
2394 See also: doc/README.Modem
2397 Configuration Settings:
2398 -----------------------
2400 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2401 undefine this when you're short of memory.
2403 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2404 width of the commands listed in the 'help' command output.
2406 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2407 prompt for user input.
2409 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2411 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2413 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2415 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2416 the application (usually a Linux kernel) when it is
2419 - CONFIG_SYS_BAUDRATE_TABLE:
2420 List of legal baudrate settings for this board.
2422 - CONFIG_SYS_CONSOLE_INFO_QUIET
2423 Suppress display of console information at boot.
2425 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2426 If the board specific function
2427 extern int overwrite_console (void);
2428 returns 1, the stdin, stderr and stdout are switched to the
2429 serial port, else the settings in the environment are used.
2431 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2432 Enable the call to overwrite_console().
2434 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2435 Enable overwrite of previous console environment settings.
2437 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2438 Begin and End addresses of the area used by the
2441 - CONFIG_SYS_ALT_MEMTEST:
2442 Enable an alternate, more extensive memory test.
2444 - CONFIG_SYS_MEMTEST_SCRATCH:
2445 Scratch address used by the alternate memory test
2446 You only need to set this if address zero isn't writeable
2448 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2449 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2450 this specified memory area will get subtracted from the top
2451 (end) of RAM and won't get "touched" at all by U-Boot. By
2452 fixing up gd->ram_size the Linux kernel should gets passed
2453 the now "corrected" memory size and won't touch it either.
2454 This should work for arch/ppc and arch/powerpc. Only Linux
2455 board ports in arch/powerpc with bootwrapper support that
2456 recalculate the memory size from the SDRAM controller setup
2457 will have to get fixed in Linux additionally.
2459 This option can be used as a workaround for the 440EPx/GRx
2460 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2463 WARNING: Please make sure that this value is a multiple of
2464 the Linux page size (normally 4k). If this is not the case,
2465 then the end address of the Linux memory will be located at a
2466 non page size aligned address and this could cause major
2469 - CONFIG_SYS_TFTP_LOADADDR:
2470 Default load address for network file downloads
2472 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2473 Enable temporary baudrate change while serial download
2475 - CONFIG_SYS_SDRAM_BASE:
2476 Physical start address of SDRAM. _Must_ be 0 here.
2478 - CONFIG_SYS_MBIO_BASE:
2479 Physical start address of Motherboard I/O (if using a
2482 - CONFIG_SYS_FLASH_BASE:
2483 Physical start address of Flash memory.
2485 - CONFIG_SYS_MONITOR_BASE:
2486 Physical start address of boot monitor code (set by
2487 make config files to be same as the text base address
2488 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2489 CONFIG_SYS_FLASH_BASE when booting from flash.
2491 - CONFIG_SYS_MONITOR_LEN:
2492 Size of memory reserved for monitor code, used to
2493 determine _at_compile_time_ (!) if the environment is
2494 embedded within the U-Boot image, or in a separate
2497 - CONFIG_SYS_MALLOC_LEN:
2498 Size of DRAM reserved for malloc() use.
2500 - CONFIG_SYS_BOOTM_LEN:
2501 Normally compressed uImages are limited to an
2502 uncompressed size of 8 MBytes. If this is not enough,
2503 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2504 to adjust this setting to your needs.
2506 - CONFIG_SYS_BOOTMAPSZ:
2507 Maximum size of memory mapped by the startup code of
2508 the Linux kernel; all data that must be processed by
2509 the Linux kernel (bd_info, boot arguments, FDT blob if
2510 used) must be put below this limit, unless "bootm_low"
2511 enviroment variable is defined and non-zero. In such case
2512 all data for the Linux kernel must be between "bootm_low"
2513 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2514 variable "bootm_mapsize" will override the value of
2515 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2516 then the value in "bootm_size" will be used instead.
2518 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2519 Enable initrd_high functionality. If defined then the
2520 initrd_high feature is enabled and the bootm ramdisk subcommand
2523 - CONFIG_SYS_BOOT_GET_CMDLINE:
2524 Enables allocating and saving kernel cmdline in space between
2525 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2527 - CONFIG_SYS_BOOT_GET_KBD:
2528 Enables allocating and saving a kernel copy of the bd_info in
2529 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2531 - CONFIG_SYS_MAX_FLASH_BANKS:
2532 Max number of Flash memory banks
2534 - CONFIG_SYS_MAX_FLASH_SECT:
2535 Max number of sectors on a Flash chip
2537 - CONFIG_SYS_FLASH_ERASE_TOUT:
2538 Timeout for Flash erase operations (in ms)
2540 - CONFIG_SYS_FLASH_WRITE_TOUT:
2541 Timeout for Flash write operations (in ms)
2543 - CONFIG_SYS_FLASH_LOCK_TOUT
2544 Timeout for Flash set sector lock bit operation (in ms)
2546 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2547 Timeout for Flash clear lock bits operation (in ms)
2549 - CONFIG_SYS_FLASH_PROTECTION
2550 If defined, hardware flash sectors protection is used
2551 instead of U-Boot software protection.
2553 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2555 Enable TFTP transfers directly to flash memory;
2556 without this option such a download has to be
2557 performed in two steps: (1) download to RAM, and (2)
2558 copy from RAM to flash.
2560 The two-step approach is usually more reliable, since
2561 you can check if the download worked before you erase
2562 the flash, but in some situations (when system RAM is
2563 too limited to allow for a temporary copy of the
2564 downloaded image) this option may be very useful.
2566 - CONFIG_SYS_FLASH_CFI:
2567 Define if the flash driver uses extra elements in the
2568 common flash structure for storing flash geometry.
2570 - CONFIG_FLASH_CFI_DRIVER
2571 This option also enables the building of the cfi_flash driver
2572 in the drivers directory
2574 - CONFIG_FLASH_CFI_MTD
2575 This option enables the building of the cfi_mtd driver
2576 in the drivers directory. The driver exports CFI flash
2579 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2580 Use buffered writes to flash.
2582 - CONFIG_FLASH_SPANSION_S29WS_N
2583 s29ws-n MirrorBit flash has non-standard addresses for buffered
2586 - CONFIG_SYS_FLASH_QUIET_TEST
2587 If this option is defined, the common CFI flash doesn't
2588 print it's warning upon not recognized FLASH banks. This
2589 is useful, if some of the configured banks are only
2590 optionally available.
2592 - CONFIG_FLASH_SHOW_PROGRESS
2593 If defined (must be an integer), print out countdown
2594 digits and dots. Recommended value: 45 (9..1) for 80
2595 column displays, 15 (3..1) for 40 column displays.
2597 - CONFIG_SYS_RX_ETH_BUFFER:
2598 Defines the number of Ethernet receive buffers. On some
2599 Ethernet controllers it is recommended to set this value
2600 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2601 buffers can be full shortly after enabling the interface
2602 on high Ethernet traffic.
2603 Defaults to 4 if not defined.
2605 - CONFIG_ENV_MAX_ENTRIES
2607 Maximum number of entries in the hash table that is used
2608 internally to store the environment settings. The default
2609 setting is supposed to be generous and should work in most
2610 cases. This setting can be used to tune behaviour; see
2611 lib/hashtable.c for details.
2613 The following definitions that deal with the placement and management
2614 of environment data (variable area); in general, we support the
2615 following configurations:
2617 - CONFIG_BUILD_ENVCRC:
2619 Builds up envcrc with the target environment so that external utils
2620 may easily extract it and embed it in final U-Boot images.
2622 - CONFIG_ENV_IS_IN_FLASH:
2624 Define this if the environment is in flash memory.
2626 a) The environment occupies one whole flash sector, which is
2627 "embedded" in the text segment with the U-Boot code. This
2628 happens usually with "bottom boot sector" or "top boot
2629 sector" type flash chips, which have several smaller
2630 sectors at the start or the end. For instance, such a
2631 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2632 such a case you would place the environment in one of the
2633 4 kB sectors - with U-Boot code before and after it. With
2634 "top boot sector" type flash chips, you would put the
2635 environment in one of the last sectors, leaving a gap
2636 between U-Boot and the environment.
2638 - CONFIG_ENV_OFFSET:
2640 Offset of environment data (variable area) to the
2641 beginning of flash memory; for instance, with bottom boot
2642 type flash chips the second sector can be used: the offset
2643 for this sector is given here.
2645 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2649 This is just another way to specify the start address of
2650 the flash sector containing the environment (instead of
2653 - CONFIG_ENV_SECT_SIZE:
2655 Size of the sector containing the environment.
2658 b) Sometimes flash chips have few, equal sized, BIG sectors.
2659 In such a case you don't want to spend a whole sector for
2664 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2665 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2666 of this flash sector for the environment. This saves
2667 memory for the RAM copy of the environment.
2669 It may also save flash memory if you decide to use this
2670 when your environment is "embedded" within U-Boot code,
2671 since then the remainder of the flash sector could be used
2672 for U-Boot code. It should be pointed out that this is
2673 STRONGLY DISCOURAGED from a robustness point of view:
2674 updating the environment in flash makes it always
2675 necessary to erase the WHOLE sector. If something goes
2676 wrong before the contents has been restored from a copy in
2677 RAM, your target system will be dead.
2679 - CONFIG_ENV_ADDR_REDUND
2680 CONFIG_ENV_SIZE_REDUND
2682 These settings describe a second storage area used to hold
2683 a redundant copy of the environment data, so that there is
2684 a valid backup copy in case there is a power failure during
2685 a "saveenv" operation.
2687 BE CAREFUL! Any changes to the flash layout, and some changes to the
2688 source code will make it necessary to adapt <board>/u-boot.lds*
2692 - CONFIG_ENV_IS_IN_NVRAM:
2694 Define this if you have some non-volatile memory device
2695 (NVRAM, battery buffered SRAM) which you want to use for the
2701 These two #defines are used to determine the memory area you
2702 want to use for environment. It is assumed that this memory
2703 can just be read and written to, without any special
2706 BE CAREFUL! The first access to the environment happens quite early
2707 in U-Boot initalization (when we try to get the setting of for the
2708 console baudrate). You *MUST* have mapped your NVRAM area then, or
2711 Please note that even with NVRAM we still use a copy of the
2712 environment in RAM: we could work on NVRAM directly, but we want to
2713 keep settings there always unmodified except somebody uses "saveenv"
2714 to save the current settings.
2717 - CONFIG_ENV_IS_IN_EEPROM:
2719 Use this if you have an EEPROM or similar serial access
2720 device and a driver for it.
2722 - CONFIG_ENV_OFFSET:
2725 These two #defines specify the offset and size of the
2726 environment area within the total memory of your EEPROM.
2728 - CONFIG_SYS_I2C_EEPROM_ADDR:
2729 If defined, specified the chip address of the EEPROM device.
2730 The default address is zero.
2732 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2733 If defined, the number of bits used to address bytes in a
2734 single page in the EEPROM device. A 64 byte page, for example
2735 would require six bits.
2737 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2738 If defined, the number of milliseconds to delay between
2739 page writes. The default is zero milliseconds.
2741 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2742 The length in bytes of the EEPROM memory array address. Note
2743 that this is NOT the chip address length!
2745 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2746 EEPROM chips that implement "address overflow" are ones
2747 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2748 address and the extra bits end up in the "chip address" bit
2749 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2752 Note that we consider the length of the address field to
2753 still be one byte because the extra address bits are hidden
2754 in the chip address.
2756 - CONFIG_SYS_EEPROM_SIZE:
2757 The size in bytes of the EEPROM device.
2759 - CONFIG_ENV_EEPROM_IS_ON_I2C
2760 define this, if you have I2C and SPI activated, and your
2761 EEPROM, which holds the environment, is on the I2C bus.
2763 - CONFIG_I2C_ENV_EEPROM_BUS
2764 if you have an Environment on an EEPROM reached over
2765 I2C muxes, you can define here, how to reach this
2766 EEPROM. For example:
2768 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2770 EEPROM which holds the environment, is reached over
2771 a pca9547 i2c mux with address 0x70, channel 3.
2773 - CONFIG_ENV_IS_IN_DATAFLASH:
2775 Define this if you have a DataFlash memory device which you
2776 want to use for the environment.
2778 - CONFIG_ENV_OFFSET:
2782 These three #defines specify the offset and size of the
2783 environment area within the total memory of your DataFlash placed
2784 at the specified address.
2786 - CONFIG_ENV_IS_IN_NAND:
2788 Define this if you have a NAND device which you want to use
2789 for the environment.
2791 - CONFIG_ENV_OFFSET:
2794 These two #defines specify the offset and size of the environment
2795 area within the first NAND device. CONFIG_ENV_OFFSET must be
2796 aligned to an erase block boundary.
2798 - CONFIG_ENV_OFFSET_REDUND (optional):
2800 This setting describes a second storage area of CONFIG_ENV_SIZE
2801 size used to hold a redundant copy of the environment data, so
2802 that there is a valid backup copy in case there is a power failure
2803 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2804 aligned to an erase block boundary.
2806 - CONFIG_ENV_RANGE (optional):
2808 Specifies the length of the region in which the environment
2809 can be written. This should be a multiple of the NAND device's
2810 block size. Specifying a range with more erase blocks than
2811 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2812 the range to be avoided.
2814 - CONFIG_ENV_OFFSET_OOB (optional):
2816 Enables support for dynamically retrieving the offset of the
2817 environment from block zero's out-of-band data. The
2818 "nand env.oob" command can be used to record this offset.
2819 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2820 using CONFIG_ENV_OFFSET_OOB.
2822 - CONFIG_NAND_ENV_DST
2824 Defines address in RAM to which the nand_spl code should copy the
2825 environment. If redundant environment is used, it will be copied to
2826 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2828 - CONFIG_SYS_SPI_INIT_OFFSET
2830 Defines offset to the initial SPI buffer area in DPRAM. The
2831 area is used at an early stage (ROM part) if the environment
2832 is configured to reside in the SPI EEPROM: We need a 520 byte
2833 scratch DPRAM area. It is used between the two initialization
2834 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2835 to be a good choice since it makes it far enough from the
2836 start of the data area as well as from the stack pointer.
2838 Please note that the environment is read-only until the monitor
2839 has been relocated to RAM and a RAM copy of the environment has been
2840 created; also, when using EEPROM you will have to use getenv_f()
2841 until then to read environment variables.
2843 The environment is protected by a CRC32 checksum. Before the monitor
2844 is relocated into RAM, as a result of a bad CRC you will be working
2845 with the compiled-in default environment - *silently*!!! [This is
2846 necessary, because the first environment variable we need is the
2847 "baudrate" setting for the console - if we have a bad CRC, we don't
2848 have any device yet where we could complain.]
2850 Note: once the monitor has been relocated, then it will complain if
2851 the default environment is used; a new CRC is computed as soon as you
2852 use the "saveenv" command to store a valid environment.
2854 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2855 Echo the inverted Ethernet link state to the fault LED.
2857 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2858 also needs to be defined.
2860 - CONFIG_SYS_FAULT_MII_ADDR:
2861 MII address of the PHY to check for the Ethernet link state.
2863 - CONFIG_NS16550_MIN_FUNCTIONS:
2864 Define this if you desire to only have use of the NS16550_init
2865 and NS16550_putc functions for the serial driver located at
2866 drivers/serial/ns16550.c. This option is useful for saving
2867 space for already greatly restricted images, including but not
2868 limited to NAND_SPL configurations.
2870 Low Level (hardware related) configuration options:
2871 ---------------------------------------------------
2873 - CONFIG_SYS_CACHELINE_SIZE:
2874 Cache Line Size of the CPU.
2876 - CONFIG_SYS_DEFAULT_IMMR:
2877 Default address of the IMMR after system reset.
2879 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2880 and RPXsuper) to be able to adjust the position of
2881 the IMMR register after a reset.
2883 - CONFIG_SYS_CCSRBAR_DEFAULT:
2884 Default (power-on reset) physical address of CCSR on Freescale
2887 - CONFIG_SYS_CCSRBAR:
2888 Virtual address of CCSR. On a 32-bit build, this is typically
2889 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2891 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
2892 for cross-platform code that uses that macro instead.
2894 - CONFIG_SYS_CCSRBAR_PHYS:
2895 Physical address of CCSR. CCSR can be relocated to a new
2896 physical address, if desired. In this case, this macro should
2897 be set to that address. Otherwise, it should be set to the
2898 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2899 is typically relocated on 36-bit builds. It is recommended
2900 that this macro be defined via the _HIGH and _LOW macros:
2902 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2903 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2905 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
2906 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2907 either 0 (32-bit build) or 0xF (36-bit build). This macro is
2908 used in assembly code, so it must not contain typecasts or
2909 integer size suffixes (e.g. "ULL").
2911 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
2912 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2913 used in assembly code, so it must not contain typecasts or
2914 integer size suffixes (e.g. "ULL").
2916 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2917 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2918 forced to a value that ensures that CCSR is not relocated.
2920 - Floppy Disk Support:
2921 CONFIG_SYS_FDC_DRIVE_NUMBER
2923 the default drive number (default value 0)
2925 CONFIG_SYS_ISA_IO_STRIDE
2927 defines the spacing between FDC chipset registers
2930 CONFIG_SYS_ISA_IO_OFFSET
2932 defines the offset of register from address. It
2933 depends on which part of the data bus is connected to
2934 the FDC chipset. (default value 0)
2936 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2937 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2940 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2941 fdc_hw_init() is called at the beginning of the FDC
2942 setup. fdc_hw_init() must be provided by the board
2943 source code. It is used to make hardware dependant
2947 Most IDE controllers were designed to be connected with PCI
2948 interface. Only few of them were designed for AHB interface.
2949 When software is doing ATA command and data transfer to
2950 IDE devices through IDE-AHB controller, some additional
2951 registers accessing to these kind of IDE-AHB controller
2954 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2955 DO NOT CHANGE unless you know exactly what you're
2956 doing! (11-4) [MPC8xx/82xx systems only]
2958 - CONFIG_SYS_INIT_RAM_ADDR:
2960 Start address of memory area that can be used for
2961 initial data and stack; please note that this must be
2962 writable memory that is working WITHOUT special
2963 initialization, i. e. you CANNOT use normal RAM which
2964 will become available only after programming the
2965 memory controller and running certain initialization
2968 U-Boot uses the following memory types:
2969 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2970 - MPC824X: data cache
2971 - PPC4xx: data cache
2973 - CONFIG_SYS_GBL_DATA_OFFSET:
2975 Offset of the initial data structure in the memory
2976 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2977 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2978 data is located at the end of the available space
2979 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2980 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2981 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2982 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2985 On the MPC824X (or other systems that use the data
2986 cache for initial memory) the address chosen for
2987 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2988 point to an otherwise UNUSED address space between
2989 the top of RAM and the start of the PCI space.
2991 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2993 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2995 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2997 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2999 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3001 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3003 - CONFIG_SYS_OR_TIMING_SDRAM:
3006 - CONFIG_SYS_MAMR_PTA:
3007 periodic timer for refresh
3009 - CONFIG_SYS_DER: Debug Event Register (37-47)
3011 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3012 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3013 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3014 CONFIG_SYS_BR1_PRELIM:
3015 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3017 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3018 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3019 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3020 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3022 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3023 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3024 Machine Mode Register and Memory Periodic Timer
3025 Prescaler definitions (SDRAM timing)
3027 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3028 enable I2C microcode relocation patch (MPC8xx);
3029 define relocation offset in DPRAM [DSP2]
3031 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3032 enable SMC microcode relocation patch (MPC8xx);
3033 define relocation offset in DPRAM [SMC1]
3035 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3036 enable SPI microcode relocation patch (MPC8xx);
3037 define relocation offset in DPRAM [SCC4]
3039 - CONFIG_SYS_USE_OSCCLK:
3040 Use OSCM clock mode on MBX8xx board. Be careful,
3041 wrong setting might damage your board. Read
3042 doc/README.MBX before setting this variable!
3044 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3045 Offset of the bootmode word in DPRAM used by post
3046 (Power On Self Tests). This definition overrides
3047 #define'd default value in commproc.h resp.
3050 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3051 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3052 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3053 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3054 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3055 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3056 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3057 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3058 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3060 - CONFIG_PCI_DISABLE_PCIE:
3061 Disable PCI-Express on systems where it is supported but not
3065 Chip has SRIO or not
3068 Board has SRIO 1 port available
3071 Board has SRIO 2 port available
3073 - CONFIG_SYS_SRIOn_MEM_VIRT:
3074 Virtual Address of SRIO port 'n' memory region
3076 - CONFIG_SYS_SRIOn_MEM_PHYS:
3077 Physical Address of SRIO port 'n' memory region
3079 - CONFIG_SYS_SRIOn_MEM_SIZE:
3080 Size of SRIO port 'n' memory region
3082 - CONFIG_SYS_NDFC_16
3083 Defined to tell the NDFC that the NAND chip is using a
3086 - CONFIG_SYS_NDFC_EBC0_CFG
3087 Sets the EBC0_CFG register for the NDFC. If not defined
3088 a default value will be used.
3091 Get DDR timing information from an I2C EEPROM. Common
3092 with pluggable memory modules such as SODIMMs
3095 I2C address of the SPD EEPROM
3097 - CONFIG_SYS_SPD_BUS_NUM
3098 If SPD EEPROM is on an I2C bus other than the first
3099 one, specify here. Note that the value must resolve
3100 to something your driver can deal with.
3102 - CONFIG_SYS_DDR_RAW_TIMING
3103 Get DDR timing information from other than SPD. Common with
3104 soldered DDR chips onboard without SPD. DDR raw timing
3105 parameters are extracted from datasheet and hard-coded into
3106 header files or board specific files.
3108 - CONFIG_FSL_DDR_INTERACTIVE
3109 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3111 - CONFIG_SYS_83XX_DDR_USES_CS0
3112 Only for 83xx systems. If specified, then DDR should
3113 be configured using CS0 and CS1 instead of CS2 and CS3.
3115 - CONFIG_ETHER_ON_FEC[12]
3116 Define to enable FEC[12] on a 8xx series processor.
3118 - CONFIG_FEC[12]_PHY
3119 Define to the hardcoded PHY address which corresponds
3120 to the given FEC; i. e.
3121 #define CONFIG_FEC1_PHY 4
3122 means that the PHY with address 4 is connected to FEC1
3124 When set to -1, means to probe for first available.
3126 - CONFIG_FEC[12]_PHY_NORXERR
3127 The PHY does not have a RXERR line (RMII only).
3128 (so program the FEC to ignore it).
3131 Enable RMII mode for all FECs.
3132 Note that this is a global option, we can't
3133 have one FEC in standard MII mode and another in RMII mode.
3135 - CONFIG_CRC32_VERIFY
3136 Add a verify option to the crc32 command.
3139 => crc32 -v <address> <count> <crc32>
3141 Where address/count indicate a memory area
3142 and crc32 is the correct crc32 which the
3146 Add the "loopw" memory command. This only takes effect if
3147 the memory commands are activated globally (CONFIG_CMD_MEM).
3150 Add the "mdc" and "mwc" memory commands. These are cyclic
3155 This command will print 4 bytes (10,11,12,13) each 500 ms.
3157 => mwc.l 100 12345678 10
3158 This command will write 12345678 to address 100 all 10 ms.
3160 This only takes effect if the memory commands are activated
3161 globally (CONFIG_CMD_MEM).
3163 - CONFIG_SKIP_LOWLEVEL_INIT
3164 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3165 low level initializations (like setting up the memory
3166 controller) are omitted and/or U-Boot does not
3167 relocate itself into RAM.
3169 Normally this variable MUST NOT be defined. The only
3170 exception is when U-Boot is loaded (to RAM) by some
3171 other boot loader or by a debugger which performs
3172 these initializations itself.
3175 Modifies the behaviour of start.S when compiling a loader
3176 that is executed before the actual U-Boot. E.g. when
3177 compiling a NAND SPL.
3179 - CONFIG_USE_ARCH_MEMCPY
3180 CONFIG_USE_ARCH_MEMSET
3181 If these options are used a optimized version of memcpy/memset will
3182 be used if available. These functions may be faster under some
3183 conditions but may increase the binary size.
3185 Building the Software:
3186 ======================
3188 Building U-Boot has been tested in several native build environments
3189 and in many different cross environments. Of course we cannot support
3190 all possibly existing versions of cross development tools in all
3191 (potentially obsolete) versions. In case of tool chain problems we
3192 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3193 which is extensively used to build and test U-Boot.
3195 If you are not using a native environment, it is assumed that you
3196 have GNU cross compiling tools available in your path. In this case,
3197 you must set the environment variable CROSS_COMPILE in your shell.
3198 Note that no changes to the Makefile or any other source files are
3199 necessary. For example using the ELDK on a 4xx CPU, please enter:
3201 $ CROSS_COMPILE=ppc_4xx-
3202 $ export CROSS_COMPILE
3204 Note: If you wish to generate Windows versions of the utilities in
3205 the tools directory you can use the MinGW toolchain
3206 (http://www.mingw.org). Set your HOST tools to the MinGW
3207 toolchain and execute 'make tools'. For example:
3209 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3211 Binaries such as tools/mkimage.exe will be created which can
3212 be executed on computers running Windows.
3214 U-Boot is intended to be simple to build. After installing the
3215 sources you must configure U-Boot for one specific board type. This
3220 where "NAME_config" is the name of one of the existing configu-
3221 rations; see the main Makefile for supported names.
3223 Note: for some board special configuration names may exist; check if
3224 additional information is available from the board vendor; for
3225 instance, the TQM823L systems are available without (standard)
3226 or with LCD support. You can select such additional "features"
3227 when choosing the configuration, i. e.
3230 - will configure for a plain TQM823L, i. e. no LCD support
3232 make TQM823L_LCD_config
3233 - will configure for a TQM823L with U-Boot console on LCD
3238 Finally, type "make all", and you should get some working U-Boot
3239 images ready for download to / installation on your system:
3241 - "u-boot.bin" is a raw binary image
3242 - "u-boot" is an image in ELF binary format
3243 - "u-boot.srec" is in Motorola S-Record format
3245 By default the build is performed locally and the objects are saved
3246 in the source directory. One of the two methods can be used to change
3247 this behavior and build U-Boot to some external directory:
3249 1. Add O= to the make command line invocations:
3251 make O=/tmp/build distclean
3252 make O=/tmp/build NAME_config
3253 make O=/tmp/build all
3255 2. Set environment variable BUILD_DIR to point to the desired location:
3257 export BUILD_DIR=/tmp/build
3262 Note that the command line "O=" setting overrides the BUILD_DIR environment
3266 Please be aware that the Makefiles assume you are using GNU make, so
3267 for instance on NetBSD you might need to use "gmake" instead of
3271 If the system board that you have is not listed, then you will need
3272 to port U-Boot to your hardware platform. To do this, follow these
3275 1. Add a new configuration option for your board to the toplevel
3276 "Makefile" and to the "MAKEALL" script, using the existing
3277 entries as examples. Note that here and at many other places
3278 boards and other names are listed in alphabetical sort order. Please
3280 2. Create a new directory to hold your board specific code. Add any
3281 files you need. In your board directory, you will need at least
3282 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3283 3. Create a new configuration file "include/configs/<board>.h" for
3285 3. If you're porting U-Boot to a new CPU, then also create a new
3286 directory to hold your CPU specific code. Add any files you need.
3287 4. Run "make <board>_config" with your new name.
3288 5. Type "make", and you should get a working "u-boot.srec" file
3289 to be installed on your target system.
3290 6. Debug and solve any problems that might arise.
3291 [Of course, this last step is much harder than it sounds.]
3294 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3295 ==============================================================
3297 If you have modified U-Boot sources (for instance added a new board
3298 or support for new devices, a new CPU, etc.) you are expected to
3299 provide feedback to the other developers. The feedback normally takes
3300 the form of a "patch", i. e. a context diff against a certain (latest
3301 official or latest in the git repository) version of U-Boot sources.
3303 But before you submit such a patch, please verify that your modifi-
3304 cation did not break existing code. At least make sure that *ALL* of
3305 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3306 just run the "MAKEALL" script, which will configure and build U-Boot
3307 for ALL supported system. Be warned, this will take a while. You can
3308 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3309 environment variable to the script, i. e. to use the ELDK cross tools
3312 CROSS_COMPILE=ppc_8xx- MAKEALL
3314 or to build on a native PowerPC system you can type
3316 CROSS_COMPILE=' ' MAKEALL
3318 When using the MAKEALL script, the default behaviour is to build
3319 U-Boot in the source directory. This location can be changed by
3320 setting the BUILD_DIR environment variable. Also, for each target
3321 built, the MAKEALL script saves two log files (<target>.ERR and
3322 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3323 location can be changed by setting the MAKEALL_LOGDIR environment
3324 variable. For example:
3326 export BUILD_DIR=/tmp/build
3327 export MAKEALL_LOGDIR=/tmp/log
3328 CROSS_COMPILE=ppc_8xx- MAKEALL
3330 With the above settings build objects are saved in the /tmp/build,
3331 log files are saved in the /tmp/log and the source tree remains clean
3332 during the whole build process.
3335 See also "U-Boot Porting Guide" below.
3338 Monitor Commands - Overview:
3339 ============================
3341 go - start application at address 'addr'
3342 run - run commands in an environment variable
3343 bootm - boot application image from memory
3344 bootp - boot image via network using BootP/TFTP protocol
3345 tftpboot- boot image via network using TFTP protocol
3346 and env variables "ipaddr" and "serverip"
3347 (and eventually "gatewayip")
3348 tftpput - upload a file via network using TFTP protocol
3349 rarpboot- boot image via network using RARP/TFTP protocol
3350 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3351 loads - load S-Record file over serial line
3352 loadb - load binary file over serial line (kermit mode)
3354 mm - memory modify (auto-incrementing)
3355 nm - memory modify (constant address)
3356 mw - memory write (fill)
3358 cmp - memory compare
3359 crc32 - checksum calculation
3360 i2c - I2C sub-system
3361 sspi - SPI utility commands
3362 base - print or set address offset
3363 printenv- print environment variables
3364 setenv - set environment variables
3365 saveenv - save environment variables to persistent storage
3366 protect - enable or disable FLASH write protection
3367 erase - erase FLASH memory
3368 flinfo - print FLASH memory information
3369 bdinfo - print Board Info structure
3370 iminfo - print header information for application image
3371 coninfo - print console devices and informations
3372 ide - IDE sub-system
3373 loop - infinite loop on address range
3374 loopw - infinite write loop on address range
3375 mtest - simple RAM test
3376 icache - enable or disable instruction cache
3377 dcache - enable or disable data cache
3378 reset - Perform RESET of the CPU
3379 echo - echo args to console
3380 version - print monitor version
3381 help - print online help
3382 ? - alias for 'help'
3385 Monitor Commands - Detailed Description:
3386 ========================================
3390 For now: just type "help <command>".
3393 Environment Variables:
3394 ======================
3396 U-Boot supports user configuration using Environment Variables which
3397 can be made persistent by saving to Flash memory.
3399 Environment Variables are set using "setenv", printed using
3400 "printenv", and saved to Flash using "saveenv". Using "setenv"
3401 without a value can be used to delete a variable from the
3402 environment. As long as you don't save the environment you are
3403 working with an in-memory copy. In case the Flash area containing the
3404 environment is erased by accident, a default environment is provided.
3406 Some configuration options can be set using Environment Variables.
3408 List of environment variables (most likely not complete):
3410 baudrate - see CONFIG_BAUDRATE
3412 bootdelay - see CONFIG_BOOTDELAY
3414 bootcmd - see CONFIG_BOOTCOMMAND
3416 bootargs - Boot arguments when booting an RTOS image
3418 bootfile - Name of the image to load with TFTP
3420 bootm_low - Memory range available for image processing in the bootm
3421 command can be restricted. This variable is given as
3422 a hexadecimal number and defines lowest address allowed
3423 for use by the bootm command. See also "bootm_size"
3424 environment variable. Address defined by "bootm_low" is
3425 also the base of the initial memory mapping for the Linux
3426 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3429 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3430 This variable is given as a hexadecimal number and it
3431 defines the size of the memory region starting at base
3432 address bootm_low that is accessible by the Linux kernel
3433 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3434 as the default value if it is defined, and bootm_size is
3437 bootm_size - Memory range available for image processing in the bootm
3438 command can be restricted. This variable is given as
3439 a hexadecimal number and defines the size of the region
3440 allowed for use by the bootm command. See also "bootm_low"
3441 environment variable.
3443 updatefile - Location of the software update file on a TFTP server, used
3444 by the automatic software update feature. Please refer to
3445 documentation in doc/README.update for more details.
3447 autoload - if set to "no" (any string beginning with 'n'),
3448 "bootp" will just load perform a lookup of the
3449 configuration from the BOOTP server, but not try to
3450 load any image using TFTP
3452 autostart - if set to "yes", an image loaded using the "bootp",
3453 "rarpboot", "tftpboot" or "diskboot" commands will
3454 be automatically started (by internally calling
3457 If set to "no", a standalone image passed to the
3458 "bootm" command will be copied to the load address
3459 (and eventually uncompressed), but NOT be started.
3460 This can be used to load and uncompress arbitrary
3463 fdt_high - if set this restricts the maximum address that the
3464 flattened device tree will be copied into upon boot.
3465 If this is set to the special value 0xFFFFFFFF then
3466 the fdt will not be copied at all on boot. For this
3467 to work it must reside in writable memory, have
3468 sufficient padding on the end of it for u-boot to
3469 add the information it needs into it, and the memory
3470 must be accessible by the kernel.
3472 i2cfast - (PPC405GP|PPC405EP only)
3473 if set to 'y' configures Linux I2C driver for fast
3474 mode (400kHZ). This environment variable is used in
3475 initialization code. So, for changes to be effective
3476 it must be saved and board must be reset.
3478 initrd_high - restrict positioning of initrd images:
3479 If this variable is not set, initrd images will be
3480 copied to the highest possible address in RAM; this
3481 is usually what you want since it allows for
3482 maximum initrd size. If for some reason you want to
3483 make sure that the initrd image is loaded below the
3484 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3485 variable to a value of "no" or "off" or "0".
3486 Alternatively, you can set it to a maximum upper
3487 address to use (U-Boot will still check that it
3488 does not overwrite the U-Boot stack and data).
3490 For instance, when you have a system with 16 MB
3491 RAM, and want to reserve 4 MB from use by Linux,
3492 you can do this by adding "mem=12M" to the value of
3493 the "bootargs" variable. However, now you must make
3494 sure that the initrd image is placed in the first
3495 12 MB as well - this can be done with
3497 setenv initrd_high 00c00000
3499 If you set initrd_high to 0xFFFFFFFF, this is an
3500 indication to U-Boot that all addresses are legal
3501 for the Linux kernel, including addresses in flash
3502 memory. In this case U-Boot will NOT COPY the
3503 ramdisk at all. This may be useful to reduce the
3504 boot time on your system, but requires that this
3505 feature is supported by your Linux kernel.
3507 ipaddr - IP address; needed for tftpboot command
3509 loadaddr - Default load address for commands like "bootp",
3510 "rarpboot", "tftpboot", "loadb" or "diskboot"
3512 loads_echo - see CONFIG_LOADS_ECHO
3514 serverip - TFTP server IP address; needed for tftpboot command
3516 bootretry - see CONFIG_BOOT_RETRY_TIME
3518 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3520 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3522 ethprime - controls which interface is used first.
3524 ethact - controls which interface is currently active.
3525 For example you can do the following
3527 => setenv ethact FEC
3528 => ping 192.168.0.1 # traffic sent on FEC
3529 => setenv ethact SCC
3530 => ping 10.0.0.1 # traffic sent on SCC
3532 ethrotate - When set to "no" U-Boot does not go through all
3533 available network interfaces.
3534 It just stays at the currently selected interface.
3536 netretry - When set to "no" each network operation will
3537 either succeed or fail without retrying.
3538 When set to "once" the network operation will
3539 fail when all the available network interfaces
3540 are tried once without success.
3541 Useful on scripts which control the retry operation
3544 npe_ucode - set load address for the NPE microcode
3546 tftpsrcport - If this is set, the value is used for TFTP's
3549 tftpdstport - If this is set, the value is used for TFTP's UDP
3550 destination port instead of the Well Know Port 69.
3552 tftpblocksize - Block size to use for TFTP transfers; if not set,
3553 we use the TFTP server's default block size
3555 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3556 seconds, minimum value is 1000 = 1 second). Defines
3557 when a packet is considered to be lost so it has to
3558 be retransmitted. The default is 5000 = 5 seconds.
3559 Lowering this value may make downloads succeed
3560 faster in networks with high packet loss rates or
3561 with unreliable TFTP servers.
3563 vlan - When set to a value < 4095 the traffic over
3564 Ethernet is encapsulated/received over 802.1q
3567 The following image location variables contain the location of images
3568 used in booting. The "Image" column gives the role of the image and is
3569 not an environment variable name. The other columns are environment
3570 variable names. "File Name" gives the name of the file on a TFTP
3571 server, "RAM Address" gives the location in RAM the image will be
3572 loaded to, and "Flash Location" gives the image's address in NOR
3573 flash or offset in NAND flash.
3575 *Note* - these variables don't have to be defined for all boards, some
3576 boards currenlty use other variables for these purposes, and some
3577 boards use these variables for other purposes.
3579 Image File Name RAM Address Flash Location
3580 ----- --------- ----------- --------------
3581 u-boot u-boot u-boot_addr_r u-boot_addr
3582 Linux kernel bootfile kernel_addr_r kernel_addr
3583 device tree blob fdtfile fdt_addr_r fdt_addr
3584 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3586 The following environment variables may be used and automatically
3587 updated by the network boot commands ("bootp" and "rarpboot"),
3588 depending the information provided by your boot server:
3590 bootfile - see above
3591 dnsip - IP address of your Domain Name Server
3592 dnsip2 - IP address of your secondary Domain Name Server
3593 gatewayip - IP address of the Gateway (Router) to use
3594 hostname - Target hostname
3596 netmask - Subnet Mask
3597 rootpath - Pathname of the root filesystem on the NFS server
3598 serverip - see above
3601 There are two special Environment Variables:
3603 serial# - contains hardware identification information such
3604 as type string and/or serial number
3605 ethaddr - Ethernet address
3607 These variables can be set only once (usually during manufacturing of
3608 the board). U-Boot refuses to delete or overwrite these variables
3609 once they have been set once.
3612 Further special Environment Variables:
3614 ver - Contains the U-Boot version string as printed
3615 with the "version" command. This variable is
3616 readonly (see CONFIG_VERSION_VARIABLE).
3619 Please note that changes to some configuration parameters may take
3620 only effect after the next boot (yes, that's just like Windoze :-).
3623 Command Line Parsing:
3624 =====================
3626 There are two different command line parsers available with U-Boot:
3627 the old "simple" one, and the much more powerful "hush" shell:
3629 Old, simple command line parser:
3630 --------------------------------
3632 - supports environment variables (through setenv / saveenv commands)
3633 - several commands on one line, separated by ';'
3634 - variable substitution using "... ${name} ..." syntax
3635 - special characters ('$', ';') can be escaped by prefixing with '\',
3637 setenv bootcmd bootm \${address}
3638 - You can also escape text by enclosing in single apostrophes, for example:
3639 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3644 - similar to Bourne shell, with control structures like
3645 if...then...else...fi, for...do...done; while...do...done,
3646 until...do...done, ...
3647 - supports environment ("global") variables (through setenv / saveenv
3648 commands) and local shell variables (through standard shell syntax
3649 "name=value"); only environment variables can be used with "run"
3655 (1) If a command line (or an environment variable executed by a "run"
3656 command) contains several commands separated by semicolon, and
3657 one of these commands fails, then the remaining commands will be
3660 (2) If you execute several variables with one call to run (i. e.
3661 calling run with a list of variables as arguments), any failing
3662 command will cause "run" to terminate, i. e. the remaining
3663 variables are not executed.
3665 Note for Redundant Ethernet Interfaces:
3666 =======================================
3668 Some boards come with redundant Ethernet interfaces; U-Boot supports
3669 such configurations and is capable of automatic selection of a
3670 "working" interface when needed. MAC assignment works as follows:
3672 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3673 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3674 "eth1addr" (=>eth1), "eth2addr", ...
3676 If the network interface stores some valid MAC address (for instance
3677 in SROM), this is used as default address if there is NO correspon-
3678 ding setting in the environment; if the corresponding environment
3679 variable is set, this overrides the settings in the card; that means:
3681 o If the SROM has a valid MAC address, and there is no address in the
3682 environment, the SROM's address is used.
3684 o If there is no valid address in the SROM, and a definition in the
3685 environment exists, then the value from the environment variable is
3688 o If both the SROM and the environment contain a MAC address, and
3689 both addresses are the same, this MAC address is used.
3691 o If both the SROM and the environment contain a MAC address, and the
3692 addresses differ, the value from the environment is used and a
3695 o If neither SROM nor the environment contain a MAC address, an error
3698 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3699 will be programmed into hardware as part of the initialization process. This
3700 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3701 The naming convention is as follows:
3702 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3707 U-Boot is capable of booting (and performing other auxiliary operations on)
3708 images in two formats:
3710 New uImage format (FIT)
3711 -----------------------
3713 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3714 to Flattened Device Tree). It allows the use of images with multiple
3715 components (several kernels, ramdisks, etc.), with contents protected by
3716 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3722 Old image format is based on binary files which can be basically anything,
3723 preceded by a special header; see the definitions in include/image.h for
3724 details; basically, the header defines the following image properties:
3726 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3727 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3728 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3729 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3731 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3732 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3733 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3734 * Compression Type (uncompressed, gzip, bzip2)
3740 The header is marked by a special Magic Number, and both the header
3741 and the data portions of the image are secured against corruption by
3748 Although U-Boot should support any OS or standalone application
3749 easily, the main focus has always been on Linux during the design of
3752 U-Boot includes many features that so far have been part of some
3753 special "boot loader" code within the Linux kernel. Also, any
3754 "initrd" images to be used are no longer part of one big Linux image;
3755 instead, kernel and "initrd" are separate images. This implementation
3756 serves several purposes:
3758 - the same features can be used for other OS or standalone
3759 applications (for instance: using compressed images to reduce the
3760 Flash memory footprint)
3762 - it becomes much easier to port new Linux kernel versions because
3763 lots of low-level, hardware dependent stuff are done by U-Boot
3765 - the same Linux kernel image can now be used with different "initrd"
3766 images; of course this also means that different kernel images can
3767 be run with the same "initrd". This makes testing easier (you don't
3768 have to build a new "zImage.initrd" Linux image when you just
3769 change a file in your "initrd"). Also, a field-upgrade of the
3770 software is easier now.
3776 Porting Linux to U-Boot based systems:
3777 ---------------------------------------
3779 U-Boot cannot save you from doing all the necessary modifications to
3780 configure the Linux device drivers for use with your target hardware
3781 (no, we don't intend to provide a full virtual machine interface to
3784 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3786 Just make sure your machine specific header file (for instance
3787 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3788 Information structure as we define in include/asm-<arch>/u-boot.h,
3789 and make sure that your definition of IMAP_ADDR uses the same value
3790 as your U-Boot configuration in CONFIG_SYS_IMMR.
3793 Configuring the Linux kernel:
3794 -----------------------------
3796 No specific requirements for U-Boot. Make sure you have some root
3797 device (initial ramdisk, NFS) for your target system.
3800 Building a Linux Image:
3801 -----------------------
3803 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3804 not used. If you use recent kernel source, a new build target
3805 "uImage" will exist which automatically builds an image usable by
3806 U-Boot. Most older kernels also have support for a "pImage" target,
3807 which was introduced for our predecessor project PPCBoot and uses a
3808 100% compatible format.
3817 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3818 encapsulate a compressed Linux kernel image with header information,
3819 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3821 * build a standard "vmlinux" kernel image (in ELF binary format):
3823 * convert the kernel into a raw binary image:
3825 ${CROSS_COMPILE}-objcopy -O binary \
3826 -R .note -R .comment \
3827 -S vmlinux linux.bin
3829 * compress the binary image:
3833 * package compressed binary image for U-Boot:
3835 mkimage -A ppc -O linux -T kernel -C gzip \
3836 -a 0 -e 0 -n "Linux Kernel Image" \
3837 -d linux.bin.gz uImage
3840 The "mkimage" tool can also be used to create ramdisk images for use
3841 with U-Boot, either separated from the Linux kernel image, or
3842 combined into one file. "mkimage" encapsulates the images with a 64
3843 byte header containing information about target architecture,
3844 operating system, image type, compression method, entry points, time
3845 stamp, CRC32 checksums, etc.
3847 "mkimage" can be called in two ways: to verify existing images and
3848 print the header information, or to build new images.
3850 In the first form (with "-l" option) mkimage lists the information
3851 contained in the header of an existing U-Boot image; this includes
3852 checksum verification:
3854 tools/mkimage -l image
3855 -l ==> list image header information
3857 The second form (with "-d" option) is used to build a U-Boot image
3858 from a "data file" which is used as image payload:
3860 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3861 -n name -d data_file image
3862 -A ==> set architecture to 'arch'
3863 -O ==> set operating system to 'os'
3864 -T ==> set image type to 'type'
3865 -C ==> set compression type 'comp'
3866 -a ==> set load address to 'addr' (hex)
3867 -e ==> set entry point to 'ep' (hex)
3868 -n ==> set image name to 'name'
3869 -d ==> use image data from 'datafile'
3871 Right now, all Linux kernels for PowerPC systems use the same load
3872 address (0x00000000), but the entry point address depends on the
3875 - 2.2.x kernels have the entry point at 0x0000000C,
3876 - 2.3.x and later kernels have the entry point at 0x00000000.
3878 So a typical call to build a U-Boot image would read:
3880 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3881 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3882 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3883 > examples/uImage.TQM850L
3884 Image Name: 2.4.4 kernel for TQM850L
3885 Created: Wed Jul 19 02:34:59 2000
3886 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3887 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3888 Load Address: 0x00000000
3889 Entry Point: 0x00000000
3891 To verify the contents of the image (or check for corruption):
3893 -> tools/mkimage -l examples/uImage.TQM850L
3894 Image Name: 2.4.4 kernel for TQM850L
3895 Created: Wed Jul 19 02:34:59 2000
3896 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3897 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3898 Load Address: 0x00000000
3899 Entry Point: 0x00000000
3901 NOTE: for embedded systems where boot time is critical you can trade
3902 speed for memory and install an UNCOMPRESSED image instead: this
3903 needs more space in Flash, but boots much faster since it does not
3904 need to be uncompressed:
3906 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3907 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3908 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3909 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3910 > examples/uImage.TQM850L-uncompressed
3911 Image Name: 2.4.4 kernel for TQM850L
3912 Created: Wed Jul 19 02:34:59 2000
3913 Image Type: PowerPC Linux Kernel Image (uncompressed)
3914 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3915 Load Address: 0x00000000
3916 Entry Point: 0x00000000
3919 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3920 when your kernel is intended to use an initial ramdisk:
3922 -> tools/mkimage -n 'Simple Ramdisk Image' \
3923 > -A ppc -O linux -T ramdisk -C gzip \
3924 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3925 Image Name: Simple Ramdisk Image
3926 Created: Wed Jan 12 14:01:50 2000
3927 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3928 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3929 Load Address: 0x00000000
3930 Entry Point: 0x00000000
3933 Installing a Linux Image:
3934 -------------------------
3936 To downloading a U-Boot image over the serial (console) interface,
3937 you must convert the image to S-Record format:
3939 objcopy -I binary -O srec examples/image examples/image.srec
3941 The 'objcopy' does not understand the information in the U-Boot
3942 image header, so the resulting S-Record file will be relative to
3943 address 0x00000000. To load it to a given address, you need to
3944 specify the target address as 'offset' parameter with the 'loads'
3947 Example: install the image to address 0x40100000 (which on the
3948 TQM8xxL is in the first Flash bank):
3950 => erase 40100000 401FFFFF
3956 ## Ready for S-Record download ...
3957 ~>examples/image.srec
3958 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3960 15989 15990 15991 15992
3961 [file transfer complete]
3963 ## Start Addr = 0x00000000
3966 You can check the success of the download using the 'iminfo' command;
3967 this includes a checksum verification so you can be sure no data
3968 corruption happened:
3972 ## Checking Image at 40100000 ...
3973 Image Name: 2.2.13 for initrd on TQM850L
3974 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3975 Data Size: 335725 Bytes = 327 kB = 0 MB
3976 Load Address: 00000000
3977 Entry Point: 0000000c
3978 Verifying Checksum ... OK
3984 The "bootm" command is used to boot an application that is stored in
3985 memory (RAM or Flash). In case of a Linux kernel image, the contents
3986 of the "bootargs" environment variable is passed to the kernel as
3987 parameters. You can check and modify this variable using the
3988 "printenv" and "setenv" commands:
3991 => printenv bootargs
3992 bootargs=root=/dev/ram
3994 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3996 => printenv bootargs
3997 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4000 ## Booting Linux kernel at 40020000 ...
4001 Image Name: 2.2.13 for NFS on TQM850L
4002 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4003 Data Size: 381681 Bytes = 372 kB = 0 MB
4004 Load Address: 00000000
4005 Entry Point: 0000000c
4006 Verifying Checksum ... OK
4007 Uncompressing Kernel Image ... OK
4008 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
4009 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4010 time_init: decrementer frequency = 187500000/60
4011 Calibrating delay loop... 49.77 BogoMIPS
4012 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4015 If you want to boot a Linux kernel with initial RAM disk, you pass
4016 the memory addresses of both the kernel and the initrd image (PPBCOOT
4017 format!) to the "bootm" command:
4019 => imi 40100000 40200000
4021 ## Checking Image at 40100000 ...
4022 Image Name: 2.2.13 for initrd on TQM850L
4023 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4024 Data Size: 335725 Bytes = 327 kB = 0 MB
4025 Load Address: 00000000
4026 Entry Point: 0000000c
4027 Verifying Checksum ... OK
4029 ## Checking Image at 40200000 ...
4030 Image Name: Simple Ramdisk Image
4031 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4032 Data Size: 566530 Bytes = 553 kB = 0 MB
4033 Load Address: 00000000
4034 Entry Point: 00000000
4035 Verifying Checksum ... OK
4037 => bootm 40100000 40200000
4038 ## Booting Linux kernel at 40100000 ...
4039 Image Name: 2.2.13 for initrd on TQM850L
4040 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4041 Data Size: 335725 Bytes = 327 kB = 0 MB
4042 Load Address: 00000000
4043 Entry Point: 0000000c
4044 Verifying Checksum ... OK
4045 Uncompressing Kernel Image ... OK
4046 ## Loading RAMDisk Image at 40200000 ...
4047 Image Name: Simple Ramdisk Image
4048 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4049 Data Size: 566530 Bytes = 553 kB = 0 MB
4050 Load Address: 00000000
4051 Entry Point: 00000000
4052 Verifying Checksum ... OK
4053 Loading Ramdisk ... OK
4054 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
4055 Boot arguments: root=/dev/ram
4056 time_init: decrementer frequency = 187500000/60
4057 Calibrating delay loop... 49.77 BogoMIPS
4059 RAMDISK: Compressed image found at block 0
4060 VFS: Mounted root (ext2 filesystem).
4064 Boot Linux and pass a flat device tree:
4067 First, U-Boot must be compiled with the appropriate defines. See the section
4068 titled "Linux Kernel Interface" above for a more in depth explanation. The
4069 following is an example of how to start a kernel and pass an updated
4075 oft=oftrees/mpc8540ads.dtb
4076 => tftp $oftaddr $oft
4077 Speed: 1000, full duplex
4079 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4080 Filename 'oftrees/mpc8540ads.dtb'.
4081 Load address: 0x300000
4084 Bytes transferred = 4106 (100a hex)
4085 => tftp $loadaddr $bootfile
4086 Speed: 1000, full duplex
4088 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4090 Load address: 0x200000
4091 Loading:############
4093 Bytes transferred = 1029407 (fb51f hex)
4098 => bootm $loadaddr - $oftaddr
4099 ## Booting image at 00200000 ...
4100 Image Name: Linux-2.6.17-dirty
4101 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4102 Data Size: 1029343 Bytes = 1005.2 kB
4103 Load Address: 00000000
4104 Entry Point: 00000000
4105 Verifying Checksum ... OK
4106 Uncompressing Kernel Image ... OK
4107 Booting using flat device tree at 0x300000
4108 Using MPC85xx ADS machine description
4109 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4113 More About U-Boot Image Types:
4114 ------------------------------
4116 U-Boot supports the following image types:
4118 "Standalone Programs" are directly runnable in the environment
4119 provided by U-Boot; it is expected that (if they behave
4120 well) you can continue to work in U-Boot after return from
4121 the Standalone Program.
4122 "OS Kernel Images" are usually images of some Embedded OS which
4123 will take over control completely. Usually these programs
4124 will install their own set of exception handlers, device
4125 drivers, set up the MMU, etc. - this means, that you cannot
4126 expect to re-enter U-Boot except by resetting the CPU.
4127 "RAMDisk Images" are more or less just data blocks, and their
4128 parameters (address, size) are passed to an OS kernel that is
4130 "Multi-File Images" contain several images, typically an OS
4131 (Linux) kernel image and one or more data images like
4132 RAMDisks. This construct is useful for instance when you want
4133 to boot over the network using BOOTP etc., where the boot
4134 server provides just a single image file, but you want to get
4135 for instance an OS kernel and a RAMDisk image.
4137 "Multi-File Images" start with a list of image sizes, each
4138 image size (in bytes) specified by an "uint32_t" in network
4139 byte order. This list is terminated by an "(uint32_t)0".
4140 Immediately after the terminating 0 follow the images, one by
4141 one, all aligned on "uint32_t" boundaries (size rounded up to
4142 a multiple of 4 bytes).
4144 "Firmware Images" are binary images containing firmware (like
4145 U-Boot or FPGA images) which usually will be programmed to
4148 "Script files" are command sequences that will be executed by
4149 U-Boot's command interpreter; this feature is especially
4150 useful when you configure U-Boot to use a real shell (hush)
4151 as command interpreter.
4157 One of the features of U-Boot is that you can dynamically load and
4158 run "standalone" applications, which can use some resources of
4159 U-Boot like console I/O functions or interrupt services.
4161 Two simple examples are included with the sources:
4166 'examples/hello_world.c' contains a small "Hello World" Demo
4167 application; it is automatically compiled when you build U-Boot.
4168 It's configured to run at address 0x00040004, so you can play with it
4172 ## Ready for S-Record download ...
4173 ~>examples/hello_world.srec
4174 1 2 3 4 5 6 7 8 9 10 11 ...
4175 [file transfer complete]
4177 ## Start Addr = 0x00040004
4179 => go 40004 Hello World! This is a test.
4180 ## Starting application at 0x00040004 ...
4191 Hit any key to exit ...
4193 ## Application terminated, rc = 0x0
4195 Another example, which demonstrates how to register a CPM interrupt
4196 handler with the U-Boot code, can be found in 'examples/timer.c'.
4197 Here, a CPM timer is set up to generate an interrupt every second.
4198 The interrupt service routine is trivial, just printing a '.'
4199 character, but this is just a demo program. The application can be
4200 controlled by the following keys:
4202 ? - print current values og the CPM Timer registers
4203 b - enable interrupts and start timer
4204 e - stop timer and disable interrupts
4205 q - quit application
4208 ## Ready for S-Record download ...
4209 ~>examples/timer.srec
4210 1 2 3 4 5 6 7 8 9 10 11 ...
4211 [file transfer complete]
4213 ## Start Addr = 0x00040004
4216 ## Starting application at 0x00040004 ...
4219 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4222 [q, b, e, ?] Set interval 1000000 us
4225 [q, b, e, ?] ........
4226 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4229 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4232 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4235 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4237 [q, b, e, ?] ...Stopping timer
4239 [q, b, e, ?] ## Application terminated, rc = 0x0
4245 Over time, many people have reported problems when trying to use the
4246 "minicom" terminal emulation program for serial download. I (wd)
4247 consider minicom to be broken, and recommend not to use it. Under
4248 Unix, I recommend to use C-Kermit for general purpose use (and
4249 especially for kermit binary protocol download ("loadb" command), and
4250 use "cu" for S-Record download ("loads" command).
4252 Nevertheless, if you absolutely want to use it try adding this
4253 configuration to your "File transfer protocols" section:
4255 Name Program Name U/D FullScr IO-Red. Multi
4256 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4257 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4263 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4264 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4266 Building requires a cross environment; it is known to work on
4267 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4268 need gmake since the Makefiles are not compatible with BSD make).
4269 Note that the cross-powerpc package does not install include files;
4270 attempting to build U-Boot will fail because <machine/ansi.h> is
4271 missing. This file has to be installed and patched manually:
4273 # cd /usr/pkg/cross/powerpc-netbsd/include
4275 # ln -s powerpc machine
4276 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4277 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4279 Native builds *don't* work due to incompatibilities between native
4280 and U-Boot include files.
4282 Booting assumes that (the first part of) the image booted is a
4283 stage-2 loader which in turn loads and then invokes the kernel
4284 proper. Loader sources will eventually appear in the NetBSD source
4285 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4286 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4289 Implementation Internals:
4290 =========================
4292 The following is not intended to be a complete description of every
4293 implementation detail. However, it should help to understand the
4294 inner workings of U-Boot and make it easier to port it to custom
4298 Initial Stack, Global Data:
4299 ---------------------------
4301 The implementation of U-Boot is complicated by the fact that U-Boot
4302 starts running out of ROM (flash memory), usually without access to
4303 system RAM (because the memory controller is not initialized yet).
4304 This means that we don't have writable Data or BSS segments, and BSS
4305 is not initialized as zero. To be able to get a C environment working
4306 at all, we have to allocate at least a minimal stack. Implementation
4307 options for this are defined and restricted by the CPU used: Some CPU
4308 models provide on-chip memory (like the IMMR area on MPC8xx and
4309 MPC826x processors), on others (parts of) the data cache can be
4310 locked as (mis-) used as memory, etc.
4312 Chris Hallinan posted a good summary of these issues to the
4313 U-Boot mailing list:
4315 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4316 From: "Chris Hallinan" <clh@net1plus.com>
4317 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4320 Correct me if I'm wrong, folks, but the way I understand it
4321 is this: Using DCACHE as initial RAM for Stack, etc, does not
4322 require any physical RAM backing up the cache. The cleverness
4323 is that the cache is being used as a temporary supply of
4324 necessary storage before the SDRAM controller is setup. It's
4325 beyond the scope of this list to explain the details, but you
4326 can see how this works by studying the cache architecture and
4327 operation in the architecture and processor-specific manuals.
4329 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4330 is another option for the system designer to use as an
4331 initial stack/RAM area prior to SDRAM being available. Either
4332 option should work for you. Using CS 4 should be fine if your
4333 board designers haven't used it for something that would
4334 cause you grief during the initial boot! It is frequently not
4337 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4338 with your processor/board/system design. The default value
4339 you will find in any recent u-boot distribution in
4340 walnut.h should work for you. I'd set it to a value larger
4341 than your SDRAM module. If you have a 64MB SDRAM module, set
4342 it above 400_0000. Just make sure your board has no resources
4343 that are supposed to respond to that address! That code in
4344 start.S has been around a while and should work as is when
4345 you get the config right.
4350 It is essential to remember this, since it has some impact on the C
4351 code for the initialization procedures:
4353 * Initialized global data (data segment) is read-only. Do not attempt
4356 * Do not use any uninitialized global data (or implicitely initialized
4357 as zero data - BSS segment) at all - this is undefined, initiali-
4358 zation is performed later (when relocating to RAM).
4360 * Stack space is very limited. Avoid big data buffers or things like
4363 Having only the stack as writable memory limits means we cannot use
4364 normal global data to share information beween the code. But it
4365 turned out that the implementation of U-Boot can be greatly
4366 simplified by making a global data structure (gd_t) available to all
4367 functions. We could pass a pointer to this data as argument to _all_
4368 functions, but this would bloat the code. Instead we use a feature of
4369 the GCC compiler (Global Register Variables) to share the data: we
4370 place a pointer (gd) to the global data into a register which we
4371 reserve for this purpose.
4373 When choosing a register for such a purpose we are restricted by the
4374 relevant (E)ABI specifications for the current architecture, and by
4375 GCC's implementation.
4377 For PowerPC, the following registers have specific use:
4379 R2: reserved for system use
4380 R3-R4: parameter passing and return values
4381 R5-R10: parameter passing
4382 R13: small data area pointer
4386 (U-Boot also uses R12 as internal GOT pointer. r12
4387 is a volatile register so r12 needs to be reset when
4388 going back and forth between asm and C)
4390 ==> U-Boot will use R2 to hold a pointer to the global data
4392 Note: on PPC, we could use a static initializer (since the
4393 address of the global data structure is known at compile time),
4394 but it turned out that reserving a register results in somewhat
4395 smaller code - although the code savings are not that big (on
4396 average for all boards 752 bytes for the whole U-Boot image,
4397 624 text + 127 data).
4399 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4400 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4402 ==> U-Boot will use P3 to hold a pointer to the global data
4404 On ARM, the following registers are used:
4406 R0: function argument word/integer result
4407 R1-R3: function argument word
4409 R10: stack limit (used only if stack checking if enabled)
4410 R11: argument (frame) pointer
4411 R12: temporary workspace
4414 R15: program counter
4416 ==> U-Boot will use R8 to hold a pointer to the global data
4418 On Nios II, the ABI is documented here:
4419 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4421 ==> U-Boot will use gp to hold a pointer to the global data
4423 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4424 to access small data sections, so gp is free.
4426 On NDS32, the following registers are used:
4428 R0-R1: argument/return
4430 R15: temporary register for assembler
4431 R16: trampoline register
4432 R28: frame pointer (FP)
4433 R29: global pointer (GP)
4434 R30: link register (LP)
4435 R31: stack pointer (SP)
4436 PC: program counter (PC)
4438 ==> U-Boot will use R10 to hold a pointer to the global data
4440 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4441 or current versions of GCC may "optimize" the code too much.
4446 U-Boot runs in system state and uses physical addresses, i.e. the
4447 MMU is not used either for address mapping nor for memory protection.
4449 The available memory is mapped to fixed addresses using the memory
4450 controller. In this process, a contiguous block is formed for each
4451 memory type (Flash, SDRAM, SRAM), even when it consists of several
4452 physical memory banks.
4454 U-Boot is installed in the first 128 kB of the first Flash bank (on
4455 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4456 booting and sizing and initializing DRAM, the code relocates itself
4457 to the upper end of DRAM. Immediately below the U-Boot code some
4458 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4459 configuration setting]. Below that, a structure with global Board
4460 Info data is placed, followed by the stack (growing downward).
4462 Additionally, some exception handler code is copied to the low 8 kB
4463 of DRAM (0x00000000 ... 0x00001FFF).
4465 So a typical memory configuration with 16 MB of DRAM could look like
4468 0x0000 0000 Exception Vector code
4471 0x0000 2000 Free for Application Use
4477 0x00FB FF20 Monitor Stack (Growing downward)
4478 0x00FB FFAC Board Info Data and permanent copy of global data
4479 0x00FC 0000 Malloc Arena
4482 0x00FE 0000 RAM Copy of Monitor Code
4483 ... eventually: LCD or video framebuffer
4484 ... eventually: pRAM (Protected RAM - unchanged by reset)
4485 0x00FF FFFF [End of RAM]
4488 System Initialization:
4489 ----------------------
4491 In the reset configuration, U-Boot starts at the reset entry point
4492 (on most PowerPC systems at address 0x00000100). Because of the reset
4493 configuration for CS0# this is a mirror of the onboard Flash memory.
4494 To be able to re-map memory U-Boot then jumps to its link address.
4495 To be able to implement the initialization code in C, a (small!)
4496 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4497 which provide such a feature like MPC8xx or MPC8260), or in a locked
4498 part of the data cache. After that, U-Boot initializes the CPU core,
4499 the caches and the SIU.
4501 Next, all (potentially) available memory banks are mapped using a
4502 preliminary mapping. For example, we put them on 512 MB boundaries
4503 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4504 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4505 programmed for SDRAM access. Using the temporary configuration, a
4506 simple memory test is run that determines the size of the SDRAM
4509 When there is more than one SDRAM bank, and the banks are of
4510 different size, the largest is mapped first. For equal size, the first
4511 bank (CS2#) is mapped first. The first mapping is always for address
4512 0x00000000, with any additional banks following immediately to create
4513 contiguous memory starting from 0.
4515 Then, the monitor installs itself at the upper end of the SDRAM area
4516 and allocates memory for use by malloc() and for the global Board
4517 Info data; also, the exception vector code is copied to the low RAM
4518 pages, and the final stack is set up.
4520 Only after this relocation will you have a "normal" C environment;
4521 until that you are restricted in several ways, mostly because you are
4522 running from ROM, and because the code will have to be relocated to a
4526 U-Boot Porting Guide:
4527 ----------------------
4529 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4533 int main(int argc, char *argv[])
4535 sighandler_t no_more_time;
4537 signal(SIGALRM, no_more_time);
4538 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4540 if (available_money > available_manpower) {
4541 Pay consultant to port U-Boot;
4545 Download latest U-Boot source;
4547 Subscribe to u-boot mailing list;
4550 email("Hi, I am new to U-Boot, how do I get started?");
4553 Read the README file in the top level directory;
4554 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4555 Read applicable doc/*.README;
4556 Read the source, Luke;
4557 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4560 if (available_money > toLocalCurrency ($2500))
4563 Add a lot of aggravation and time;
4565 if (a similar board exists) { /* hopefully... */
4566 cp -a board/<similar> board/<myboard>
4567 cp include/configs/<similar>.h include/configs/<myboard>.h
4569 Create your own board support subdirectory;
4570 Create your own board include/configs/<myboard>.h file;
4572 Edit new board/<myboard> files
4573 Edit new include/configs/<myboard>.h
4578 Add / modify source code;
4582 email("Hi, I am having problems...");
4584 Send patch file to the U-Boot email list;
4585 if (reasonable critiques)
4586 Incorporate improvements from email list code review;
4588 Defend code as written;
4594 void no_more_time (int sig)
4603 All contributions to U-Boot should conform to the Linux kernel
4604 coding style; see the file "Documentation/CodingStyle" and the script
4605 "scripts/Lindent" in your Linux kernel source directory.
4607 Source files originating from a different project (for example the
4608 MTD subsystem) are generally exempt from these guidelines and are not
4609 reformated to ease subsequent migration to newer versions of those
4612 Please note that U-Boot is implemented in C (and to some small parts in
4613 Assembler); no C++ is used, so please do not use C++ style comments (//)
4616 Please also stick to the following formatting rules:
4617 - remove any trailing white space
4618 - use TAB characters for indentation and vertical alignment, not spaces
4619 - make sure NOT to use DOS '\r\n' line feeds
4620 - do not add more than 2 consecutive empty lines to source files
4621 - do not add trailing empty lines to source files
4623 Submissions which do not conform to the standards may be returned
4624 with a request to reformat the changes.
4630 Since the number of patches for U-Boot is growing, we need to
4631 establish some rules. Submissions which do not conform to these rules
4632 may be rejected, even when they contain important and valuable stuff.
4634 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4636 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4637 see http://lists.denx.de/mailman/listinfo/u-boot
4639 When you send a patch, please include the following information with
4642 * For bug fixes: a description of the bug and how your patch fixes
4643 this bug. Please try to include a way of demonstrating that the
4644 patch actually fixes something.
4646 * For new features: a description of the feature and your
4649 * A CHANGELOG entry as plaintext (separate from the patch)
4651 * For major contributions, your entry to the CREDITS file
4653 * When you add support for a new board, don't forget to add this
4654 board to the MAINTAINERS file, too.
4656 * If your patch adds new configuration options, don't forget to
4657 document these in the README file.
4659 * The patch itself. If you are using git (which is *strongly*
4660 recommended) you can easily generate the patch using the
4661 "git format-patch". If you then use "git send-email" to send it to
4662 the U-Boot mailing list, you will avoid most of the common problems
4663 with some other mail clients.
4665 If you cannot use git, use "diff -purN OLD NEW". If your version of
4666 diff does not support these options, then get the latest version of
4669 The current directory when running this command shall be the parent
4670 directory of the U-Boot source tree (i. e. please make sure that
4671 your patch includes sufficient directory information for the
4674 We prefer patches as plain text. MIME attachments are discouraged,
4675 and compressed attachments must not be used.
4677 * If one logical set of modifications affects or creates several
4678 files, all these changes shall be submitted in a SINGLE patch file.
4680 * Changesets that contain different, unrelated modifications shall be
4681 submitted as SEPARATE patches, one patch per changeset.
4686 * Before sending the patch, run the MAKEALL script on your patched
4687 source tree and make sure that no errors or warnings are reported
4688 for any of the boards.
4690 * Keep your modifications to the necessary minimum: A patch
4691 containing several unrelated changes or arbitrary reformats will be
4692 returned with a request to re-formatting / split it.
4694 * If you modify existing code, make sure that your new code does not
4695 add to the memory footprint of the code ;-) Small is beautiful!
4696 When adding new features, these should compile conditionally only
4697 (using #ifdef), and the resulting code with the new feature
4698 disabled must not need more memory than the old code without your
4701 * Remember that there is a size limit of 100 kB per message on the
4702 u-boot mailing list. Bigger patches will be moderated. If they are
4703 reasonable and not too big, they will be acknowledged. But patches
4704 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob