2 # (C) Copyright 2000 - 2012
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)
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 - Pre-console putc():
642 Prior to the console being initialised, console output is
643 normally silently discarded. This can be annoying if a
644 panic() happens in this time.
646 If the CONFIG_PRE_CONSOLE_PUTC option is defined, then
647 U-Boot will call board_pre_console_putc() for each output
648 character in this case, This function should try to output
649 the character if possible, perhaps on all available UARTs
650 (it will need to do this directly, since the console code
651 is not functional yet). Note that if the panic happens
652 early enough, then it is possible that board_init_f()
653 (or even arch_cpu_init() on ARM) has not been called yet.
654 You should init all clocks, GPIOs, etc. that are needed
655 to get the character out. Baud rates will need to default
656 to something sensible.
658 - Safe printf() functions
659 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
660 the printf() functions. These are defined in
661 include/vsprintf.h and include snprintf(), vsnprintf() and
662 so on. Code size increase is approximately 300-500 bytes.
663 If this option is not given then these functions will
664 silently discard their buffer size argument - this means
665 you are not getting any overflow checking in this case.
667 - Boot Delay: CONFIG_BOOTDELAY - in seconds
668 Delay before automatically booting the default image;
669 set to -1 to disable autoboot.
671 See doc/README.autoboot for these options that
672 work with CONFIG_BOOTDELAY. None are required.
673 CONFIG_BOOT_RETRY_TIME
674 CONFIG_BOOT_RETRY_MIN
675 CONFIG_AUTOBOOT_KEYED
676 CONFIG_AUTOBOOT_PROMPT
677 CONFIG_AUTOBOOT_DELAY_STR
678 CONFIG_AUTOBOOT_STOP_STR
679 CONFIG_AUTOBOOT_DELAY_STR2
680 CONFIG_AUTOBOOT_STOP_STR2
681 CONFIG_ZERO_BOOTDELAY_CHECK
682 CONFIG_RESET_TO_RETRY
686 Only needed when CONFIG_BOOTDELAY is enabled;
687 define a command string that is automatically executed
688 when no character is read on the console interface
689 within "Boot Delay" after reset.
692 This can be used to pass arguments to the bootm
693 command. The value of CONFIG_BOOTARGS goes into the
694 environment value "bootargs".
696 CONFIG_RAMBOOT and CONFIG_NFSBOOT
697 The value of these goes into the environment as
698 "ramboot" and "nfsboot" respectively, and can be used
699 as a convenience, when switching between booting from
705 When this option is #defined, the existence of the
706 environment variable "preboot" will be checked
707 immediately before starting the CONFIG_BOOTDELAY
708 countdown and/or running the auto-boot command resp.
709 entering interactive mode.
711 This feature is especially useful when "preboot" is
712 automatically generated or modified. For an example
713 see the LWMON board specific code: here "preboot" is
714 modified when the user holds down a certain
715 combination of keys on the (special) keyboard when
718 - Serial Download Echo Mode:
720 If defined to 1, all characters received during a
721 serial download (using the "loads" command) are
722 echoed back. This might be needed by some terminal
723 emulations (like "cu"), but may as well just take
724 time on others. This setting #define's the initial
725 value of the "loads_echo" environment variable.
727 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
729 Select one of the baudrates listed in
730 CONFIG_SYS_BAUDRATE_TABLE, see below.
733 Monitor commands can be included or excluded
734 from the build by using the #include files
735 "config_cmd_all.h" and #undef'ing unwanted
736 commands, or using "config_cmd_default.h"
737 and augmenting with additional #define's
740 The default command configuration includes all commands
741 except those marked below with a "*".
743 CONFIG_CMD_ASKENV * ask for env variable
744 CONFIG_CMD_BDI bdinfo
745 CONFIG_CMD_BEDBUG * Include BedBug Debugger
746 CONFIG_CMD_BMP * BMP support
747 CONFIG_CMD_BSP * Board specific commands
748 CONFIG_CMD_BOOTD bootd
749 CONFIG_CMD_CACHE * icache, dcache
750 CONFIG_CMD_CONSOLE coninfo
751 CONFIG_CMD_CRC32 * crc32
752 CONFIG_CMD_DATE * support for RTC, date/time...
753 CONFIG_CMD_DHCP * DHCP support
754 CONFIG_CMD_DIAG * Diagnostics
755 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
756 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
757 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
758 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
759 CONFIG_CMD_DTT * Digital Therm and Thermostat
760 CONFIG_CMD_ECHO echo arguments
761 CONFIG_CMD_EDITENV edit env variable
762 CONFIG_CMD_EEPROM * EEPROM read/write support
763 CONFIG_CMD_ELF * bootelf, bootvx
764 CONFIG_CMD_EXPORTENV * export the environment
765 CONFIG_CMD_SAVEENV saveenv
766 CONFIG_CMD_FDC * Floppy Disk Support
767 CONFIG_CMD_FAT * FAT partition support
768 CONFIG_CMD_FDOS * Dos diskette Support
769 CONFIG_CMD_FLASH flinfo, erase, protect
770 CONFIG_CMD_FPGA FPGA device initialization support
771 CONFIG_CMD_GO * the 'go' command (exec code)
772 CONFIG_CMD_GREPENV * search environment
773 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
774 CONFIG_CMD_I2C * I2C serial bus support
775 CONFIG_CMD_IDE * IDE harddisk support
776 CONFIG_CMD_IMI iminfo
777 CONFIG_CMD_IMLS List all found images
778 CONFIG_CMD_IMMAP * IMMR dump support
779 CONFIG_CMD_IMPORTENV * import an environment
780 CONFIG_CMD_IRQ * irqinfo
781 CONFIG_CMD_ITEST Integer/string test of 2 values
782 CONFIG_CMD_JFFS2 * JFFS2 Support
783 CONFIG_CMD_KGDB * kgdb
784 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
785 CONFIG_CMD_LOADB loadb
786 CONFIG_CMD_LOADS loads
787 CONFIG_CMD_MD5SUM print md5 message digest
788 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
789 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
791 CONFIG_CMD_MISC Misc functions like sleep etc
792 CONFIG_CMD_MMC * MMC memory mapped support
793 CONFIG_CMD_MII * MII utility commands
794 CONFIG_CMD_MTDPARTS * MTD partition support
795 CONFIG_CMD_NAND * NAND support
796 CONFIG_CMD_NET bootp, tftpboot, rarpboot
797 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
798 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
799 CONFIG_CMD_PCI * pciinfo
800 CONFIG_CMD_PCMCIA * PCMCIA support
801 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
803 CONFIG_CMD_PORTIO * Port I/O
804 CONFIG_CMD_REGINFO * Register dump
805 CONFIG_CMD_RUN run command in env variable
806 CONFIG_CMD_SAVES * save S record dump
807 CONFIG_CMD_SCSI * SCSI Support
808 CONFIG_CMD_SDRAM * print SDRAM configuration information
809 (requires CONFIG_CMD_I2C)
810 CONFIG_CMD_SETGETDCR Support for DCR Register access
812 CONFIG_CMD_SHA1SUM print sha1 memory digest
813 (requires CONFIG_CMD_MEMORY)
814 CONFIG_CMD_SOURCE "source" command Support
815 CONFIG_CMD_SPI * SPI serial bus support
816 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
817 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
818 CONFIG_CMD_TIME * run command and report execution time
819 CONFIG_CMD_USB * USB support
820 CONFIG_CMD_CDP * Cisco Discover Protocol support
821 CONFIG_CMD_FSL * Microblaze FSL support
824 EXAMPLE: If you want all functions except of network
825 support you can write:
827 #include "config_cmd_all.h"
828 #undef CONFIG_CMD_NET
831 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
833 Note: Don't enable the "icache" and "dcache" commands
834 (configuration option CONFIG_CMD_CACHE) unless you know
835 what you (and your U-Boot users) are doing. Data
836 cache cannot be enabled on systems like the 8xx or
837 8260 (where accesses to the IMMR region must be
838 uncached), and it cannot be disabled on all other
839 systems where we (mis-) use the data cache to hold an
840 initial stack and some data.
843 XXX - this list needs to get updated!
847 If this variable is defined, U-Boot will use a device tree
848 to configure its devices, instead of relying on statically
849 compiled #defines in the board file. This option is
850 experimental and only available on a few boards. The device
851 tree is available in the global data as gd->fdt_blob.
853 U-Boot needs to get its device tree from somewhere. This can
854 be done using one of the two options below:
857 If this variable is defined, U-Boot will embed a device tree
858 binary in its image. This device tree file should be in the
859 board directory and called <soc>-<board>.dts. The binary file
860 is then picked up in board_init_f() and made available through
861 the global data structure as gd->blob.
864 If this variable is defined, U-Boot will build a device tree
865 binary. It will be called u-boot.dtb. Architecture-specific
866 code will locate it at run-time. Generally this works by:
868 cat u-boot.bin u-boot.dtb >image.bin
870 and in fact, U-Boot does this for you, creating a file called
871 u-boot-dtb.bin which is useful in the common case. You can
872 still use the individual files if you need something more
877 If this variable is defined, it enables watchdog
878 support for the SoC. There must be support in the SoC
879 specific code for a watchdog. For the 8xx and 8260
880 CPUs, the SIU Watchdog feature is enabled in the SYPCR
881 register. When supported for a specific SoC is
882 available, then no further board specific code should
886 When using a watchdog circuitry external to the used
887 SoC, then define this variable and provide board
888 specific code for the "hw_watchdog_reset" function.
891 CONFIG_VERSION_VARIABLE
892 If this variable is defined, an environment variable
893 named "ver" is created by U-Boot showing the U-Boot
894 version as printed by the "version" command.
895 This variable is readonly.
899 When CONFIG_CMD_DATE is selected, the type of the RTC
900 has to be selected, too. Define exactly one of the
903 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
904 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
905 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
906 CONFIG_RTC_MC146818 - use MC146818 RTC
907 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
908 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
909 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
910 CONFIG_RTC_DS164x - use Dallas DS164x RTC
911 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
912 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
913 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
914 CONFIG_SYS_RV3029_TCR - enable trickle charger on
917 Note that if the RTC uses I2C, then the I2C interface
918 must also be configured. See I2C Support, below.
921 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
922 CONFIG_PCA953X_INFO - enable pca953x info command
924 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
925 chip-ngpio pairs that tell the PCA953X driver the number of
926 pins supported by a particular chip.
928 Note that if the GPIO device uses I2C, then the I2C interface
929 must also be configured. See I2C Support, below.
933 When CONFIG_TIMESTAMP is selected, the timestamp
934 (date and time) of an image is printed by image
935 commands like bootm or iminfo. This option is
936 automatically enabled when you select CONFIG_CMD_DATE .
939 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
940 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
942 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
943 CONFIG_CMD_SCSI) you must configure support for at
944 least one partition type as well.
947 CONFIG_IDE_RESET_ROUTINE - this is defined in several
948 board configurations files but used nowhere!
950 CONFIG_IDE_RESET - is this is defined, IDE Reset will
951 be performed by calling the function
952 ide_set_reset(int reset)
953 which has to be defined in a board specific file
958 Set this to enable ATAPI support.
963 Set this to enable support for disks larger than 137GB
964 Also look at CONFIG_SYS_64BIT_LBA.
965 Whithout these , LBA48 support uses 32bit variables and will 'only'
966 support disks up to 2.1TB.
968 CONFIG_SYS_64BIT_LBA:
969 When enabled, makes the IDE subsystem use 64bit sector addresses.
973 At the moment only there is only support for the
974 SYM53C8XX SCSI controller; define
975 CONFIG_SCSI_SYM53C8XX to enable it.
977 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
978 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
979 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
980 maximum numbers of LUNs, SCSI ID's and target
982 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
984 - NETWORK Support (PCI):
986 Support for Intel 8254x/8257x gigabit chips.
989 Utility code for direct access to the SPI bus on Intel 8257x.
990 This does not do anything useful unless you set at least one
991 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
993 CONFIG_E1000_SPI_GENERIC
994 Allow generic access to the SPI bus on the Intel 8257x, for
995 example with the "sspi" command.
998 Management command for E1000 devices. When used on devices
999 with SPI support you can reprogram the EEPROM from U-Boot.
1001 CONFIG_E1000_FALLBACK_MAC
1002 default MAC for empty EEPROM after production.
1005 Support for Intel 82557/82559/82559ER chips.
1006 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1007 write routine for first time initialisation.
1010 Support for Digital 2114x chips.
1011 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1012 modem chip initialisation (KS8761/QS6611).
1015 Support for National dp83815 chips.
1018 Support for National dp8382[01] gigabit chips.
1020 - NETWORK Support (other):
1022 CONFIG_DRIVER_AT91EMAC
1023 Support for AT91RM9200 EMAC.
1026 Define this to use reduced MII inteface
1028 CONFIG_DRIVER_AT91EMAC_QUIET
1029 If this defined, the driver is quiet.
1030 The driver doen't show link status messages.
1032 CONFIG_CALXEDA_XGMAC
1033 Support for the Calxeda XGMAC device
1035 CONFIG_DRIVER_LAN91C96
1036 Support for SMSC's LAN91C96 chips.
1038 CONFIG_LAN91C96_BASE
1039 Define this to hold the physical address
1040 of the LAN91C96's I/O space
1042 CONFIG_LAN91C96_USE_32_BIT
1043 Define this to enable 32 bit addressing
1045 CONFIG_DRIVER_SMC91111
1046 Support for SMSC's LAN91C111 chip
1048 CONFIG_SMC91111_BASE
1049 Define this to hold the physical address
1050 of the device (I/O space)
1052 CONFIG_SMC_USE_32_BIT
1053 Define this if data bus is 32 bits
1055 CONFIG_SMC_USE_IOFUNCS
1056 Define this to use i/o functions instead of macros
1057 (some hardware wont work with macros)
1059 CONFIG_DRIVER_TI_EMAC
1060 Support for davinci emac
1062 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1063 Define this if you have more then 3 PHYs.
1066 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1068 CONFIG_FTGMAC100_EGIGA
1069 Define this to use GE link update with gigabit PHY.
1070 Define this if FTGMAC100 is connected to gigabit PHY.
1071 If your system has 10/100 PHY only, it might not occur
1072 wrong behavior. Because PHY usually return timeout or
1073 useless data when polling gigabit status and gigabit
1074 control registers. This behavior won't affect the
1075 correctnessof 10/100 link speed update.
1078 Support for SMSC's LAN911x and LAN921x chips
1081 Define this to hold the physical address
1082 of the device (I/O space)
1084 CONFIG_SMC911X_32_BIT
1085 Define this if data bus is 32 bits
1087 CONFIG_SMC911X_16_BIT
1088 Define this if data bus is 16 bits. If your processor
1089 automatically converts one 32 bit word to two 16 bit
1090 words you may also try CONFIG_SMC911X_32_BIT.
1093 Support for Renesas on-chip Ethernet controller
1095 CONFIG_SH_ETHER_USE_PORT
1096 Define the number of ports to be used
1098 CONFIG_SH_ETHER_PHY_ADDR
1099 Define the ETH PHY's address
1101 CONFIG_SH_ETHER_CACHE_WRITEBACK
1102 If this option is set, the driver enables cache flush.
1105 CONFIG_GENERIC_LPC_TPM
1106 Support for generic parallel port TPM devices. Only one device
1107 per system is supported at this time.
1109 CONFIG_TPM_TIS_BASE_ADDRESS
1110 Base address where the generic TPM device is mapped
1111 to. Contemporary x86 systems usually map it at
1115 At the moment only the UHCI host controller is
1116 supported (PIP405, MIP405, MPC5200); define
1117 CONFIG_USB_UHCI to enable it.
1118 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1119 and define CONFIG_USB_STORAGE to enable the USB
1122 Supported are USB Keyboards and USB Floppy drives
1124 MPC5200 USB requires additional defines:
1126 for 528 MHz Clock: 0x0001bbbb
1130 for differential drivers: 0x00001000
1131 for single ended drivers: 0x00005000
1132 for differential drivers on PSC3: 0x00000100
1133 for single ended drivers on PSC3: 0x00004100
1134 CONFIG_SYS_USB_EVENT_POLL
1135 May be defined to allow interrupt polling
1136 instead of using asynchronous interrupts
1139 Define the below if you wish to use the USB console.
1140 Once firmware is rebuilt from a serial console issue the
1141 command "setenv stdin usbtty; setenv stdout usbtty" and
1142 attach your USB cable. The Unix command "dmesg" should print
1143 it has found a new device. The environment variable usbtty
1144 can be set to gserial or cdc_acm to enable your device to
1145 appear to a USB host as a Linux gserial device or a
1146 Common Device Class Abstract Control Model serial device.
1147 If you select usbtty = gserial you should be able to enumerate
1149 # modprobe usbserial vendor=0xVendorID product=0xProductID
1150 else if using cdc_acm, simply setting the environment
1151 variable usbtty to be cdc_acm should suffice. The following
1152 might be defined in YourBoardName.h
1155 Define this to build a UDC device
1158 Define this to have a tty type of device available to
1159 talk to the UDC device
1161 CONFIG_SYS_CONSOLE_IS_IN_ENV
1162 Define this if you want stdin, stdout &/or stderr to
1166 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1167 Derive USB clock from external clock "blah"
1168 - CONFIG_SYS_USB_EXTC_CLK 0x02
1170 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1171 Derive USB clock from brgclk
1172 - CONFIG_SYS_USB_BRG_CLK 0x04
1174 If you have a USB-IF assigned VendorID then you may wish to
1175 define your own vendor specific values either in BoardName.h
1176 or directly in usbd_vendor_info.h. If you don't define
1177 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1178 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1179 should pretend to be a Linux device to it's target host.
1181 CONFIG_USBD_MANUFACTURER
1182 Define this string as the name of your company for
1183 - CONFIG_USBD_MANUFACTURER "my company"
1185 CONFIG_USBD_PRODUCT_NAME
1186 Define this string as the name of your product
1187 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1189 CONFIG_USBD_VENDORID
1190 Define this as your assigned Vendor ID from the USB
1191 Implementors Forum. This *must* be a genuine Vendor ID
1192 to avoid polluting the USB namespace.
1193 - CONFIG_USBD_VENDORID 0xFFFF
1195 CONFIG_USBD_PRODUCTID
1196 Define this as the unique Product ID
1198 - CONFIG_USBD_PRODUCTID 0xFFFF
1200 - ULPI Layer Support:
1201 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1202 the generic ULPI layer. The generic layer accesses the ULPI PHY
1203 via the platform viewport, so you need both the genric layer and
1204 the viewport enabled. Currently only Chipidea/ARC based
1205 viewport is supported.
1206 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1207 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1210 The MMC controller on the Intel PXA is supported. To
1211 enable this define CONFIG_MMC. The MMC can be
1212 accessed from the boot prompt by mapping the device
1213 to physical memory similar to flash. Command line is
1214 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1215 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1218 Support for Renesas on-chip MMCIF controller
1220 CONFIG_SH_MMCIF_ADDR
1221 Define the base address of MMCIF registers
1224 Define the clock frequency for MMCIF
1226 - Journaling Flash filesystem support:
1227 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1228 CONFIG_JFFS2_NAND_DEV
1229 Define these for a default partition on a NAND device
1231 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1232 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1233 Define these for a default partition on a NOR device
1235 CONFIG_SYS_JFFS_CUSTOM_PART
1236 Define this to create an own partition. You have to provide a
1237 function struct part_info* jffs2_part_info(int part_num)
1239 If you define only one JFFS2 partition you may also want to
1240 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1241 to disable the command chpart. This is the default when you
1242 have not defined a custom partition
1244 - FAT(File Allocation Table) filesystem write function support:
1246 Support for saving memory data as a file
1247 in FAT formatted partition
1252 Define this to enable standard (PC-Style) keyboard
1256 Standard PC keyboard driver with US (is default) and
1257 GERMAN key layout (switch via environment 'keymap=de') support.
1258 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1259 for cfb_console. Supports cursor blinking.
1264 Define this to enable video support (for output to
1267 CONFIG_VIDEO_CT69000
1269 Enable Chips & Technologies 69000 Video chip
1271 CONFIG_VIDEO_SMI_LYNXEM
1272 Enable Silicon Motion SMI 712/710/810 Video chip. The
1273 video output is selected via environment 'videoout'
1274 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1277 For the CT69000 and SMI_LYNXEM drivers, videomode is
1278 selected via environment 'videomode'. Two different ways
1280 - "videomode=num" 'num' is a standard LiLo mode numbers.
1281 Following standard modes are supported (* is default):
1283 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1284 -------------+---------------------------------------------
1285 8 bits | 0x301* 0x303 0x305 0x161 0x307
1286 15 bits | 0x310 0x313 0x316 0x162 0x319
1287 16 bits | 0x311 0x314 0x317 0x163 0x31A
1288 24 bits | 0x312 0x315 0x318 ? 0x31B
1289 -------------+---------------------------------------------
1290 (i.e. setenv videomode 317; saveenv; reset;)
1292 - "videomode=bootargs" all the video parameters are parsed
1293 from the bootargs. (See drivers/video/videomodes.c)
1296 CONFIG_VIDEO_SED13806
1297 Enable Epson SED13806 driver. This driver supports 8bpp
1298 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1299 or CONFIG_VIDEO_SED13806_16BPP
1302 Enable the Freescale DIU video driver. Reference boards for
1303 SOCs that have a DIU should define this macro to enable DIU
1304 support, and should also define these other macros:
1310 CONFIG_VIDEO_SW_CURSOR
1311 CONFIG_VGA_AS_SINGLE_DEVICE
1313 CONFIG_VIDEO_BMP_LOGO
1315 The DIU driver will look for the 'video-mode' environment
1316 variable, and if defined, enable the DIU as a console during
1317 boot. See the documentation file README.video for a
1318 description of this variable.
1323 Define this to enable a custom keyboard support.
1324 This simply calls drv_keyboard_init() which must be
1325 defined in your board-specific files.
1326 The only board using this so far is RBC823.
1328 - LCD Support: CONFIG_LCD
1330 Define this to enable LCD support (for output to LCD
1331 display); also select one of the supported displays
1332 by defining one of these:
1336 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1338 CONFIG_NEC_NL6448AC33:
1340 NEC NL6448AC33-18. Active, color, single scan.
1342 CONFIG_NEC_NL6448BC20
1344 NEC NL6448BC20-08. 6.5", 640x480.
1345 Active, color, single scan.
1347 CONFIG_NEC_NL6448BC33_54
1349 NEC NL6448BC33-54. 10.4", 640x480.
1350 Active, color, single scan.
1354 Sharp 320x240. Active, color, single scan.
1355 It isn't 16x9, and I am not sure what it is.
1357 CONFIG_SHARP_LQ64D341
1359 Sharp LQ64D341 display, 640x480.
1360 Active, color, single scan.
1364 HLD1045 display, 640x480.
1365 Active, color, single scan.
1369 Optrex CBL50840-2 NF-FW 99 22 M5
1371 Hitachi LMG6912RPFC-00T
1375 320x240. Black & white.
1377 Normally display is black on white background; define
1378 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1380 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1382 If this option is set, the environment is checked for
1383 a variable "splashimage". If found, the usual display
1384 of logo, copyright and system information on the LCD
1385 is suppressed and the BMP image at the address
1386 specified in "splashimage" is loaded instead. The
1387 console is redirected to the "nulldev", too. This
1388 allows for a "silent" boot where a splash screen is
1389 loaded very quickly after power-on.
1391 CONFIG_SPLASH_SCREEN_ALIGN
1393 If this option is set the splash image can be freely positioned
1394 on the screen. Environment variable "splashpos" specifies the
1395 position as "x,y". If a positive number is given it is used as
1396 number of pixel from left/top. If a negative number is given it
1397 is used as number of pixel from right/bottom. You can also
1398 specify 'm' for centering the image.
1401 setenv splashpos m,m
1402 => image at center of screen
1404 setenv splashpos 30,20
1405 => image at x = 30 and y = 20
1407 setenv splashpos -10,m
1408 => vertically centered image
1409 at x = dspWidth - bmpWidth - 9
1411 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1413 If this option is set, additionally to standard BMP
1414 images, gzipped BMP images can be displayed via the
1415 splashscreen support or the bmp command.
1417 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1419 If this option is set, 8-bit RLE compressed BMP images
1420 can be displayed via the splashscreen support or the
1423 - Compression support:
1426 If this option is set, support for bzip2 compressed
1427 images is included. If not, only uncompressed and gzip
1428 compressed images are supported.
1430 NOTE: the bzip2 algorithm requires a lot of RAM, so
1431 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1436 If this option is set, support for lzma compressed
1439 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1440 requires an amount of dynamic memory that is given by the
1443 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1445 Where lc and lp stand for, respectively, Literal context bits
1446 and Literal pos bits.
1448 This value is upper-bounded by 14MB in the worst case. Anyway,
1449 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1450 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1451 a very small buffer.
1453 Use the lzmainfo tool to determinate the lc and lp values and
1454 then calculate the amount of needed dynamic memory (ensuring
1455 the appropriate CONFIG_SYS_MALLOC_LEN value).
1460 The address of PHY on MII bus.
1462 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1464 The clock frequency of the MII bus
1468 If this option is set, support for speed/duplex
1469 detection of gigabit PHY is included.
1471 CONFIG_PHY_RESET_DELAY
1473 Some PHY like Intel LXT971A need extra delay after
1474 reset before any MII register access is possible.
1475 For such PHY, set this option to the usec delay
1476 required. (minimum 300usec for LXT971A)
1478 CONFIG_PHY_CMD_DELAY (ppc4xx)
1480 Some PHY like Intel LXT971A need extra delay after
1481 command issued before MII status register can be read
1491 Define a default value for Ethernet address to use
1492 for the respective Ethernet interface, in case this
1493 is not determined automatically.
1498 Define a default value for the IP address to use for
1499 the default Ethernet interface, in case this is not
1500 determined through e.g. bootp.
1501 (Environment variable "ipaddr")
1503 - Server IP address:
1506 Defines a default value for the IP address of a TFTP
1507 server to contact when using the "tftboot" command.
1508 (Environment variable "serverip")
1510 CONFIG_KEEP_SERVERADDR
1512 Keeps the server's MAC address, in the env 'serveraddr'
1513 for passing to bootargs (like Linux's netconsole option)
1515 - Gateway IP address:
1518 Defines a default value for the IP address of the
1519 default router where packets to other networks are
1521 (Environment variable "gatewayip")
1526 Defines a default value for the subnet mask (or
1527 routing prefix) which is used to determine if an IP
1528 address belongs to the local subnet or needs to be
1529 forwarded through a router.
1530 (Environment variable "netmask")
1532 - Multicast TFTP Mode:
1535 Defines whether you want to support multicast TFTP as per
1536 rfc-2090; for example to work with atftp. Lets lots of targets
1537 tftp down the same boot image concurrently. Note: the Ethernet
1538 driver in use must provide a function: mcast() to join/leave a
1541 - BOOTP Recovery Mode:
1542 CONFIG_BOOTP_RANDOM_DELAY
1544 If you have many targets in a network that try to
1545 boot using BOOTP, you may want to avoid that all
1546 systems send out BOOTP requests at precisely the same
1547 moment (which would happen for instance at recovery
1548 from a power failure, when all systems will try to
1549 boot, thus flooding the BOOTP server. Defining
1550 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1551 inserted before sending out BOOTP requests. The
1552 following delays are inserted then:
1554 1st BOOTP request: delay 0 ... 1 sec
1555 2nd BOOTP request: delay 0 ... 2 sec
1556 3rd BOOTP request: delay 0 ... 4 sec
1558 BOOTP requests: delay 0 ... 8 sec
1560 - DHCP Advanced Options:
1561 You can fine tune the DHCP functionality by defining
1562 CONFIG_BOOTP_* symbols:
1564 CONFIG_BOOTP_SUBNETMASK
1565 CONFIG_BOOTP_GATEWAY
1566 CONFIG_BOOTP_HOSTNAME
1567 CONFIG_BOOTP_NISDOMAIN
1568 CONFIG_BOOTP_BOOTPATH
1569 CONFIG_BOOTP_BOOTFILESIZE
1572 CONFIG_BOOTP_SEND_HOSTNAME
1573 CONFIG_BOOTP_NTPSERVER
1574 CONFIG_BOOTP_TIMEOFFSET
1575 CONFIG_BOOTP_VENDOREX
1577 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1578 environment variable, not the BOOTP server.
1580 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1581 serverip from a DHCP server, it is possible that more
1582 than one DNS serverip is offered to the client.
1583 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1584 serverip will be stored in the additional environment
1585 variable "dnsip2". The first DNS serverip is always
1586 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1589 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1590 to do a dynamic update of a DNS server. To do this, they
1591 need the hostname of the DHCP requester.
1592 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1593 of the "hostname" environment variable is passed as
1594 option 12 to the DHCP server.
1596 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1598 A 32bit value in microseconds for a delay between
1599 receiving a "DHCP Offer" and sending the "DHCP Request".
1600 This fixes a problem with certain DHCP servers that don't
1601 respond 100% of the time to a "DHCP request". E.g. On an
1602 AT91RM9200 processor running at 180MHz, this delay needed
1603 to be *at least* 15,000 usec before a Windows Server 2003
1604 DHCP server would reply 100% of the time. I recommend at
1605 least 50,000 usec to be safe. The alternative is to hope
1606 that one of the retries will be successful but note that
1607 the DHCP timeout and retry process takes a longer than
1611 CONFIG_CDP_DEVICE_ID
1613 The device id used in CDP trigger frames.
1615 CONFIG_CDP_DEVICE_ID_PREFIX
1617 A two character string which is prefixed to the MAC address
1622 A printf format string which contains the ascii name of
1623 the port. Normally is set to "eth%d" which sets
1624 eth0 for the first Ethernet, eth1 for the second etc.
1626 CONFIG_CDP_CAPABILITIES
1628 A 32bit integer which indicates the device capabilities;
1629 0x00000010 for a normal host which does not forwards.
1633 An ascii string containing the version of the software.
1637 An ascii string containing the name of the platform.
1641 A 32bit integer sent on the trigger.
1643 CONFIG_CDP_POWER_CONSUMPTION
1645 A 16bit integer containing the power consumption of the
1646 device in .1 of milliwatts.
1648 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1650 A byte containing the id of the VLAN.
1652 - Status LED: CONFIG_STATUS_LED
1654 Several configurations allow to display the current
1655 status using a LED. For instance, the LED will blink
1656 fast while running U-Boot code, stop blinking as
1657 soon as a reply to a BOOTP request was received, and
1658 start blinking slow once the Linux kernel is running
1659 (supported by a status LED driver in the Linux
1660 kernel). Defining CONFIG_STATUS_LED enables this
1663 - CAN Support: CONFIG_CAN_DRIVER
1665 Defining CONFIG_CAN_DRIVER enables CAN driver support
1666 on those systems that support this (optional)
1667 feature, like the TQM8xxL modules.
1669 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1671 These enable I2C serial bus commands. Defining either of
1672 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1673 include the appropriate I2C driver for the selected CPU.
1675 This will allow you to use i2c commands at the u-boot
1676 command line (as long as you set CONFIG_CMD_I2C in
1677 CONFIG_COMMANDS) and communicate with i2c based realtime
1678 clock chips. See common/cmd_i2c.c for a description of the
1679 command line interface.
1681 CONFIG_HARD_I2C selects a hardware I2C controller.
1683 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1684 bit-banging) driver instead of CPM or similar hardware
1687 There are several other quantities that must also be
1688 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1690 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1691 to be the frequency (in Hz) at which you wish your i2c bus
1692 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1693 the CPU's i2c node address).
1695 Now, the u-boot i2c code for the mpc8xx
1696 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1697 and so its address should therefore be cleared to 0 (See,
1698 eg, MPC823e User's Manual p.16-473). So, set
1699 CONFIG_SYS_I2C_SLAVE to 0.
1701 CONFIG_SYS_I2C_INIT_MPC5XXX
1703 When a board is reset during an i2c bus transfer
1704 chips might think that the current transfer is still
1705 in progress. Reset the slave devices by sending start
1706 commands until the slave device responds.
1708 That's all that's required for CONFIG_HARD_I2C.
1710 If you use the software i2c interface (CONFIG_SOFT_I2C)
1711 then the following macros need to be defined (examples are
1712 from include/configs/lwmon.h):
1716 (Optional). Any commands necessary to enable the I2C
1717 controller or configure ports.
1719 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1723 (Only for MPC8260 CPU). The I/O port to use (the code
1724 assumes both bits are on the same port). Valid values
1725 are 0..3 for ports A..D.
1729 The code necessary to make the I2C data line active
1730 (driven). If the data line is open collector, this
1733 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1737 The code necessary to make the I2C data line tri-stated
1738 (inactive). If the data line is open collector, this
1741 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1745 Code that returns TRUE if the I2C data line is high,
1748 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1752 If <bit> is TRUE, sets the I2C data line high. If it
1753 is FALSE, it clears it (low).
1755 eg: #define I2C_SDA(bit) \
1756 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1757 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1761 If <bit> is TRUE, sets the I2C clock line high. If it
1762 is FALSE, it clears it (low).
1764 eg: #define I2C_SCL(bit) \
1765 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1766 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1770 This delay is invoked four times per clock cycle so this
1771 controls the rate of data transfer. The data rate thus
1772 is 1 / (I2C_DELAY * 4). Often defined to be something
1775 #define I2C_DELAY udelay(2)
1777 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1779 If your arch supports the generic GPIO framework (asm/gpio.h),
1780 then you may alternatively define the two GPIOs that are to be
1781 used as SCL / SDA. Any of the previous I2C_xxx macros will
1782 have GPIO-based defaults assigned to them as appropriate.
1784 You should define these to the GPIO value as given directly to
1785 the generic GPIO functions.
1787 CONFIG_SYS_I2C_INIT_BOARD
1789 When a board is reset during an i2c bus transfer
1790 chips might think that the current transfer is still
1791 in progress. On some boards it is possible to access
1792 the i2c SCLK line directly, either by using the
1793 processor pin as a GPIO or by having a second pin
1794 connected to the bus. If this option is defined a
1795 custom i2c_init_board() routine in boards/xxx/board.c
1796 is run early in the boot sequence.
1798 CONFIG_SYS_I2C_BOARD_LATE_INIT
1800 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1801 defined a custom i2c_board_late_init() routine in
1802 boards/xxx/board.c is run AFTER the operations in i2c_init()
1803 is completed. This callpoint can be used to unreset i2c bus
1804 using CPU i2c controller register accesses for CPUs whose i2c
1805 controller provide such a method. It is called at the end of
1806 i2c_init() to allow i2c_init operations to setup the i2c bus
1807 controller on the CPU (e.g. setting bus speed & slave address).
1809 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1811 This option enables configuration of bi_iic_fast[] flags
1812 in u-boot bd_info structure based on u-boot environment
1813 variable "i2cfast". (see also i2cfast)
1815 CONFIG_I2C_MULTI_BUS
1817 This option allows the use of multiple I2C buses, each of which
1818 must have a controller. At any point in time, only one bus is
1819 active. To switch to a different bus, use the 'i2c dev' command.
1820 Note that bus numbering is zero-based.
1822 CONFIG_SYS_I2C_NOPROBES
1824 This option specifies a list of I2C devices that will be skipped
1825 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1826 is set, specify a list of bus-device pairs. Otherwise, specify
1827 a 1D array of device addresses
1830 #undef CONFIG_I2C_MULTI_BUS
1831 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1833 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1835 #define CONFIG_I2C_MULTI_BUS
1836 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1838 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1840 CONFIG_SYS_SPD_BUS_NUM
1842 If defined, then this indicates the I2C bus number for DDR SPD.
1843 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1845 CONFIG_SYS_RTC_BUS_NUM
1847 If defined, then this indicates the I2C bus number for the RTC.
1848 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1850 CONFIG_SYS_DTT_BUS_NUM
1852 If defined, then this indicates the I2C bus number for the DTT.
1853 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1855 CONFIG_SYS_I2C_DTT_ADDR:
1857 If defined, specifies the I2C address of the DTT device.
1858 If not defined, then U-Boot uses predefined value for
1859 specified DTT device.
1863 Define this option if you want to use Freescale's I2C driver in
1864 drivers/i2c/fsl_i2c.c.
1868 Define this option if you have I2C devices reached over 1 .. n
1869 I2C Muxes like the pca9544a. This option addes a new I2C
1870 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1871 new I2C Bus to the existing I2C Busses. If you select the
1872 new Bus with "i2c dev", u-bbot sends first the commandos for
1873 the muxes to activate this new "bus".
1875 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1879 Adding a new I2C Bus reached over 2 pca9544a muxes
1880 The First mux with address 70 and channel 6
1881 The Second mux with address 71 and channel 4
1883 => i2c bus pca9544a:70:6:pca9544a:71:4
1885 Use the "i2c bus" command without parameter, to get a list
1886 of I2C Busses with muxes:
1889 Busses reached over muxes:
1891 reached over Mux(es):
1894 reached over Mux(es):
1899 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1900 u-boot first sends the command to the mux@70 to enable
1901 channel 6, and then the command to the mux@71 to enable
1904 After that, you can use the "normal" i2c commands as
1905 usual to communicate with your I2C devices behind
1908 This option is actually implemented for the bitbanging
1909 algorithm in common/soft_i2c.c and for the Hardware I2C
1910 Bus on the MPC8260. But it should be not so difficult
1911 to add this option to other architectures.
1913 CONFIG_SOFT_I2C_READ_REPEATED_START
1915 defining this will force the i2c_read() function in
1916 the soft_i2c driver to perform an I2C repeated start
1917 between writing the address pointer and reading the
1918 data. If this define is omitted the default behaviour
1919 of doing a stop-start sequence will be used. Most I2C
1920 devices can use either method, but some require one or
1923 - SPI Support: CONFIG_SPI
1925 Enables SPI driver (so far only tested with
1926 SPI EEPROM, also an instance works with Crystal A/D and
1927 D/As on the SACSng board)
1931 Enables the driver for SPI controller on SuperH. Currently
1932 only SH7757 is supported.
1936 Enables extended (16-bit) SPI EEPROM addressing.
1937 (symmetrical to CONFIG_I2C_X)
1941 Enables a software (bit-bang) SPI driver rather than
1942 using hardware support. This is a general purpose
1943 driver that only requires three general I/O port pins
1944 (two outputs, one input) to function. If this is
1945 defined, the board configuration must define several
1946 SPI configuration items (port pins to use, etc). For
1947 an example, see include/configs/sacsng.h.
1951 Enables a hardware SPI driver for general-purpose reads
1952 and writes. As with CONFIG_SOFT_SPI, the board configuration
1953 must define a list of chip-select function pointers.
1954 Currently supported on some MPC8xxx processors. For an
1955 example, see include/configs/mpc8349emds.h.
1959 Enables the driver for the SPI controllers on i.MX and MXC
1960 SoCs. Currently i.MX31/35/51 are supported.
1962 - FPGA Support: CONFIG_FPGA
1964 Enables FPGA subsystem.
1966 CONFIG_FPGA_<vendor>
1968 Enables support for specific chip vendors.
1971 CONFIG_FPGA_<family>
1973 Enables support for FPGA family.
1974 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1978 Specify the number of FPGA devices to support.
1980 CONFIG_SYS_FPGA_PROG_FEEDBACK
1982 Enable printing of hash marks during FPGA configuration.
1984 CONFIG_SYS_FPGA_CHECK_BUSY
1986 Enable checks on FPGA configuration interface busy
1987 status by the configuration function. This option
1988 will require a board or device specific function to
1993 If defined, a function that provides delays in the FPGA
1994 configuration driver.
1996 CONFIG_SYS_FPGA_CHECK_CTRLC
1997 Allow Control-C to interrupt FPGA configuration
1999 CONFIG_SYS_FPGA_CHECK_ERROR
2001 Check for configuration errors during FPGA bitfile
2002 loading. For example, abort during Virtex II
2003 configuration if the INIT_B line goes low (which
2004 indicated a CRC error).
2006 CONFIG_SYS_FPGA_WAIT_INIT
2008 Maximum time to wait for the INIT_B line to deassert
2009 after PROB_B has been deasserted during a Virtex II
2010 FPGA configuration sequence. The default time is 500
2013 CONFIG_SYS_FPGA_WAIT_BUSY
2015 Maximum time to wait for BUSY to deassert during
2016 Virtex II FPGA configuration. The default is 5 ms.
2018 CONFIG_SYS_FPGA_WAIT_CONFIG
2020 Time to wait after FPGA configuration. The default is
2023 - Configuration Management:
2026 If defined, this string will be added to the U-Boot
2027 version information (U_BOOT_VERSION)
2029 - Vendor Parameter Protection:
2031 U-Boot considers the values of the environment
2032 variables "serial#" (Board Serial Number) and
2033 "ethaddr" (Ethernet Address) to be parameters that
2034 are set once by the board vendor / manufacturer, and
2035 protects these variables from casual modification by
2036 the user. Once set, these variables are read-only,
2037 and write or delete attempts are rejected. You can
2038 change this behaviour:
2040 If CONFIG_ENV_OVERWRITE is #defined in your config
2041 file, the write protection for vendor parameters is
2042 completely disabled. Anybody can change or delete
2045 Alternatively, if you #define _both_ CONFIG_ETHADDR
2046 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2047 Ethernet address is installed in the environment,
2048 which can be changed exactly ONCE by the user. [The
2049 serial# is unaffected by this, i. e. it remains
2055 Define this variable to enable the reservation of
2056 "protected RAM", i. e. RAM which is not overwritten
2057 by U-Boot. Define CONFIG_PRAM to hold the number of
2058 kB you want to reserve for pRAM. You can overwrite
2059 this default value by defining an environment
2060 variable "pram" to the number of kB you want to
2061 reserve. Note that the board info structure will
2062 still show the full amount of RAM. If pRAM is
2063 reserved, a new environment variable "mem" will
2064 automatically be defined to hold the amount of
2065 remaining RAM in a form that can be passed as boot
2066 argument to Linux, for instance like that:
2068 setenv bootargs ... mem=\${mem}
2071 This way you can tell Linux not to use this memory,
2072 either, which results in a memory region that will
2073 not be affected by reboots.
2075 *WARNING* If your board configuration uses automatic
2076 detection of the RAM size, you must make sure that
2077 this memory test is non-destructive. So far, the
2078 following board configurations are known to be
2081 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2082 HERMES, IP860, RPXlite, LWMON, LANTEC,
2088 Define this variable to stop the system in case of a
2089 fatal error, so that you have to reset it manually.
2090 This is probably NOT a good idea for an embedded
2091 system where you want the system to reboot
2092 automatically as fast as possible, but it may be
2093 useful during development since you can try to debug
2094 the conditions that lead to the situation.
2096 CONFIG_NET_RETRY_COUNT
2098 This variable defines the number of retries for
2099 network operations like ARP, RARP, TFTP, or BOOTP
2100 before giving up the operation. If not defined, a
2101 default value of 5 is used.
2105 Timeout waiting for an ARP reply in milliseconds.
2107 - Command Interpreter:
2108 CONFIG_AUTO_COMPLETE
2110 Enable auto completion of commands using TAB.
2112 Note that this feature has NOT been implemented yet
2113 for the "hush" shell.
2116 CONFIG_SYS_HUSH_PARSER
2118 Define this variable to enable the "hush" shell (from
2119 Busybox) as command line interpreter, thus enabling
2120 powerful command line syntax like
2121 if...then...else...fi conditionals or `&&' and '||'
2122 constructs ("shell scripts").
2124 If undefined, you get the old, much simpler behaviour
2125 with a somewhat smaller memory footprint.
2128 CONFIG_SYS_PROMPT_HUSH_PS2
2130 This defines the secondary prompt string, which is
2131 printed when the command interpreter needs more input
2132 to complete a command. Usually "> ".
2136 In the current implementation, the local variables
2137 space and global environment variables space are
2138 separated. Local variables are those you define by
2139 simply typing `name=value'. To access a local
2140 variable later on, you have write `$name' or
2141 `${name}'; to execute the contents of a variable
2142 directly type `$name' at the command prompt.
2144 Global environment variables are those you use
2145 setenv/printenv to work with. To run a command stored
2146 in such a variable, you need to use the run command,
2147 and you must not use the '$' sign to access them.
2149 To store commands and special characters in a
2150 variable, please use double quotation marks
2151 surrounding the whole text of the variable, instead
2152 of the backslashes before semicolons and special
2155 - Commandline Editing and History:
2156 CONFIG_CMDLINE_EDITING
2158 Enable editing and History functions for interactive
2159 commandline input operations
2161 - Default Environment:
2162 CONFIG_EXTRA_ENV_SETTINGS
2164 Define this to contain any number of null terminated
2165 strings (variable = value pairs) that will be part of
2166 the default environment compiled into the boot image.
2168 For example, place something like this in your
2169 board's config file:
2171 #define CONFIG_EXTRA_ENV_SETTINGS \
2175 Warning: This method is based on knowledge about the
2176 internal format how the environment is stored by the
2177 U-Boot code. This is NOT an official, exported
2178 interface! Although it is unlikely that this format
2179 will change soon, there is no guarantee either.
2180 You better know what you are doing here.
2182 Note: overly (ab)use of the default environment is
2183 discouraged. Make sure to check other ways to preset
2184 the environment like the "source" command or the
2187 - DataFlash Support:
2188 CONFIG_HAS_DATAFLASH
2190 Defining this option enables DataFlash features and
2191 allows to read/write in Dataflash via the standard
2194 - SystemACE Support:
2197 Adding this option adds support for Xilinx SystemACE
2198 chips attached via some sort of local bus. The address
2199 of the chip must also be defined in the
2200 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2202 #define CONFIG_SYSTEMACE
2203 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2205 When SystemACE support is added, the "ace" device type
2206 becomes available to the fat commands, i.e. fatls.
2208 - TFTP Fixed UDP Port:
2211 If this is defined, the environment variable tftpsrcp
2212 is used to supply the TFTP UDP source port value.
2213 If tftpsrcp isn't defined, the normal pseudo-random port
2214 number generator is used.
2216 Also, the environment variable tftpdstp is used to supply
2217 the TFTP UDP destination port value. If tftpdstp isn't
2218 defined, the normal port 69 is used.
2220 The purpose for tftpsrcp is to allow a TFTP server to
2221 blindly start the TFTP transfer using the pre-configured
2222 target IP address and UDP port. This has the effect of
2223 "punching through" the (Windows XP) firewall, allowing
2224 the remainder of the TFTP transfer to proceed normally.
2225 A better solution is to properly configure the firewall,
2226 but sometimes that is not allowed.
2228 - Show boot progress:
2229 CONFIG_SHOW_BOOT_PROGRESS
2231 Defining this option allows to add some board-
2232 specific code (calling a user-provided function
2233 "show_boot_progress(int)") that enables you to show
2234 the system's boot progress on some display (for
2235 example, some LED's) on your board. At the moment,
2236 the following checkpoints are implemented:
2238 Legacy uImage format:
2241 1 common/cmd_bootm.c before attempting to boot an image
2242 -1 common/cmd_bootm.c Image header has bad magic number
2243 2 common/cmd_bootm.c Image header has correct magic number
2244 -2 common/cmd_bootm.c Image header has bad checksum
2245 3 common/cmd_bootm.c Image header has correct checksum
2246 -3 common/cmd_bootm.c Image data has bad checksum
2247 4 common/cmd_bootm.c Image data has correct checksum
2248 -4 common/cmd_bootm.c Image is for unsupported architecture
2249 5 common/cmd_bootm.c Architecture check OK
2250 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2251 6 common/cmd_bootm.c Image Type check OK
2252 -6 common/cmd_bootm.c gunzip uncompression error
2253 -7 common/cmd_bootm.c Unimplemented compression type
2254 7 common/cmd_bootm.c Uncompression OK
2255 8 common/cmd_bootm.c No uncompress/copy overwrite error
2256 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2258 9 common/image.c Start initial ramdisk verification
2259 -10 common/image.c Ramdisk header has bad magic number
2260 -11 common/image.c Ramdisk header has bad checksum
2261 10 common/image.c Ramdisk header is OK
2262 -12 common/image.c Ramdisk data has bad checksum
2263 11 common/image.c Ramdisk data has correct checksum
2264 12 common/image.c Ramdisk verification complete, start loading
2265 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2266 13 common/image.c Start multifile image verification
2267 14 common/image.c No initial ramdisk, no multifile, continue.
2269 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2271 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2272 -31 post/post.c POST test failed, detected by post_output_backlog()
2273 -32 post/post.c POST test failed, detected by post_run_single()
2275 34 common/cmd_doc.c before loading a Image from a DOC device
2276 -35 common/cmd_doc.c Bad usage of "doc" command
2277 35 common/cmd_doc.c correct usage of "doc" command
2278 -36 common/cmd_doc.c No boot device
2279 36 common/cmd_doc.c correct boot device
2280 -37 common/cmd_doc.c Unknown Chip ID on boot device
2281 37 common/cmd_doc.c correct chip ID found, device available
2282 -38 common/cmd_doc.c Read Error on boot device
2283 38 common/cmd_doc.c reading Image header from DOC device OK
2284 -39 common/cmd_doc.c Image header has bad magic number
2285 39 common/cmd_doc.c Image header has correct magic number
2286 -40 common/cmd_doc.c Error reading Image from DOC device
2287 40 common/cmd_doc.c Image header has correct magic number
2288 41 common/cmd_ide.c before loading a Image from a IDE device
2289 -42 common/cmd_ide.c Bad usage of "ide" command
2290 42 common/cmd_ide.c correct usage of "ide" command
2291 -43 common/cmd_ide.c No boot device
2292 43 common/cmd_ide.c boot device found
2293 -44 common/cmd_ide.c Device not available
2294 44 common/cmd_ide.c Device available
2295 -45 common/cmd_ide.c wrong partition selected
2296 45 common/cmd_ide.c partition selected
2297 -46 common/cmd_ide.c Unknown partition table
2298 46 common/cmd_ide.c valid partition table found
2299 -47 common/cmd_ide.c Invalid partition type
2300 47 common/cmd_ide.c correct partition type
2301 -48 common/cmd_ide.c Error reading Image Header on boot device
2302 48 common/cmd_ide.c reading Image Header from IDE device OK
2303 -49 common/cmd_ide.c Image header has bad magic number
2304 49 common/cmd_ide.c Image header has correct magic number
2305 -50 common/cmd_ide.c Image header has bad checksum
2306 50 common/cmd_ide.c Image header has correct checksum
2307 -51 common/cmd_ide.c Error reading Image from IDE device
2308 51 common/cmd_ide.c reading Image from IDE device OK
2309 52 common/cmd_nand.c before loading a Image from a NAND device
2310 -53 common/cmd_nand.c Bad usage of "nand" command
2311 53 common/cmd_nand.c correct usage of "nand" command
2312 -54 common/cmd_nand.c No boot device
2313 54 common/cmd_nand.c boot device found
2314 -55 common/cmd_nand.c Unknown Chip ID on boot device
2315 55 common/cmd_nand.c correct chip ID found, device available
2316 -56 common/cmd_nand.c Error reading Image Header on boot device
2317 56 common/cmd_nand.c reading Image Header from NAND device OK
2318 -57 common/cmd_nand.c Image header has bad magic number
2319 57 common/cmd_nand.c Image header has correct magic number
2320 -58 common/cmd_nand.c Error reading Image from NAND device
2321 58 common/cmd_nand.c reading Image from NAND device OK
2323 -60 common/env_common.c Environment has a bad CRC, using default
2325 64 net/eth.c starting with Ethernet configuration.
2326 -64 net/eth.c no Ethernet found.
2327 65 net/eth.c Ethernet found.
2329 -80 common/cmd_net.c usage wrong
2330 80 common/cmd_net.c before calling NetLoop()
2331 -81 common/cmd_net.c some error in NetLoop() occurred
2332 81 common/cmd_net.c NetLoop() back without error
2333 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2334 82 common/cmd_net.c trying automatic boot
2335 83 common/cmd_net.c running "source" command
2336 -83 common/cmd_net.c some error in automatic boot or "source" command
2337 84 common/cmd_net.c end without errors
2342 100 common/cmd_bootm.c Kernel FIT Image has correct format
2343 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2344 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2345 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2346 102 common/cmd_bootm.c Kernel unit name specified
2347 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2348 103 common/cmd_bootm.c Found configuration node
2349 104 common/cmd_bootm.c Got kernel subimage node offset
2350 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2351 105 common/cmd_bootm.c Kernel subimage hash verification OK
2352 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2353 106 common/cmd_bootm.c Architecture check OK
2354 -106 common/cmd_bootm.c Kernel subimage has wrong type
2355 107 common/cmd_bootm.c Kernel subimage type OK
2356 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2357 108 common/cmd_bootm.c Got kernel subimage data/size
2358 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2359 -109 common/cmd_bootm.c Can't get kernel subimage type
2360 -110 common/cmd_bootm.c Can't get kernel subimage comp
2361 -111 common/cmd_bootm.c Can't get kernel subimage os
2362 -112 common/cmd_bootm.c Can't get kernel subimage load address
2363 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2365 120 common/image.c Start initial ramdisk verification
2366 -120 common/image.c Ramdisk FIT image has incorrect format
2367 121 common/image.c Ramdisk FIT image has correct format
2368 122 common/image.c No ramdisk subimage unit name, using configuration
2369 -122 common/image.c Can't get configuration for ramdisk subimage
2370 123 common/image.c Ramdisk unit name specified
2371 -124 common/image.c Can't get ramdisk subimage node offset
2372 125 common/image.c Got ramdisk subimage node offset
2373 -125 common/image.c Ramdisk subimage hash verification failed
2374 126 common/image.c Ramdisk subimage hash verification OK
2375 -126 common/image.c Ramdisk subimage for unsupported architecture
2376 127 common/image.c Architecture check OK
2377 -127 common/image.c Can't get ramdisk subimage data/size
2378 128 common/image.c Got ramdisk subimage data/size
2379 129 common/image.c Can't get ramdisk load address
2380 -129 common/image.c Got ramdisk load address
2382 -130 common/cmd_doc.c Incorrect FIT image format
2383 131 common/cmd_doc.c FIT image format OK
2385 -140 common/cmd_ide.c Incorrect FIT image format
2386 141 common/cmd_ide.c FIT image format OK
2388 -150 common/cmd_nand.c Incorrect FIT image format
2389 151 common/cmd_nand.c FIT image format OK
2391 - Standalone program support:
2392 CONFIG_STANDALONE_LOAD_ADDR
2394 This option defines a board specific value for the
2395 address where standalone program gets loaded, thus
2396 overwriting the architecture dependent default
2399 - Frame Buffer Address:
2402 Define CONFIG_FB_ADDR if you want to use specific
2403 address for frame buffer.
2404 Then system will reserve the frame buffer address to
2405 defined address instead of lcd_setmem (this function
2406 grabs the memory for frame buffer by panel's size).
2408 Please see board_init_f function.
2410 - Automatic software updates via TFTP server
2412 CONFIG_UPDATE_TFTP_CNT_MAX
2413 CONFIG_UPDATE_TFTP_MSEC_MAX
2415 These options enable and control the auto-update feature;
2416 for a more detailed description refer to doc/README.update.
2418 - MTD Support (mtdparts command, UBI support)
2421 Adds the MTD device infrastructure from the Linux kernel.
2422 Needed for mtdparts command support.
2424 CONFIG_MTD_PARTITIONS
2426 Adds the MTD partitioning infrastructure from the Linux
2427 kernel. Needed for UBI support.
2431 Enable building of SPL globally.
2433 CONFIG_SPL_TEXT_BASE
2434 TEXT_BASE for linking the SPL binary.
2437 LDSCRIPT for linking the SPL binary.
2439 CONFIG_SPL_LIBCOMMON_SUPPORT
2440 Support for common/libcommon.o in SPL binary
2442 CONFIG_SPL_LIBDISK_SUPPORT
2443 Support for disk/libdisk.o in SPL binary
2445 CONFIG_SPL_I2C_SUPPORT
2446 Support for drivers/i2c/libi2c.o in SPL binary
2448 CONFIG_SPL_GPIO_SUPPORT
2449 Support for drivers/gpio/libgpio.o in SPL binary
2451 CONFIG_SPL_MMC_SUPPORT
2452 Support for drivers/mmc/libmmc.o in SPL binary
2454 CONFIG_SPL_SERIAL_SUPPORT
2455 Support for drivers/serial/libserial.o in SPL binary
2457 CONFIG_SPL_SPI_FLASH_SUPPORT
2458 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2460 CONFIG_SPL_SPI_SUPPORT
2461 Support for drivers/spi/libspi.o in SPL binary
2463 CONFIG_SPL_FAT_SUPPORT
2464 Support for fs/fat/libfat.o in SPL binary
2466 CONFIG_SPL_LIBGENERIC_SUPPORT
2467 Support for lib/libgeneric.o in SPL binary
2472 [so far only for SMDK2400 boards]
2474 - Modem support enable:
2475 CONFIG_MODEM_SUPPORT
2477 - RTS/CTS Flow control enable:
2480 - Modem debug support:
2481 CONFIG_MODEM_SUPPORT_DEBUG
2483 Enables debugging stuff (char screen[1024], dbg())
2484 for modem support. Useful only with BDI2000.
2486 - Interrupt support (PPC):
2488 There are common interrupt_init() and timer_interrupt()
2489 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2490 for CPU specific initialization. interrupt_init_cpu()
2491 should set decrementer_count to appropriate value. If
2492 CPU resets decrementer automatically after interrupt
2493 (ppc4xx) it should set decrementer_count to zero.
2494 timer_interrupt() calls timer_interrupt_cpu() for CPU
2495 specific handling. If board has watchdog / status_led
2496 / other_activity_monitor it works automatically from
2497 general timer_interrupt().
2501 In the target system modem support is enabled when a
2502 specific key (key combination) is pressed during
2503 power-on. Otherwise U-Boot will boot normally
2504 (autoboot). The key_pressed() function is called from
2505 board_init(). Currently key_pressed() is a dummy
2506 function, returning 1 and thus enabling modem
2509 If there are no modem init strings in the
2510 environment, U-Boot proceed to autoboot; the
2511 previous output (banner, info printfs) will be
2514 See also: doc/README.Modem
2516 Board initialization settings:
2517 ------------------------------
2519 During Initialization u-boot calls a number of board specific functions
2520 to allow the preparation of board specific prerequisites, e.g. pin setup
2521 before drivers are initialized. To enable these callbacks the
2522 following configuration macros have to be defined. Currently this is
2523 architecture specific, so please check arch/your_architecture/lib/board.c
2524 typically in board_init_f() and board_init_r().
2526 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2527 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2528 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2529 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2531 Configuration Settings:
2532 -----------------------
2534 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2535 undefine this when you're short of memory.
2537 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2538 width of the commands listed in the 'help' command output.
2540 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2541 prompt for user input.
2543 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2545 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2547 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2549 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2550 the application (usually a Linux kernel) when it is
2553 - CONFIG_SYS_BAUDRATE_TABLE:
2554 List of legal baudrate settings for this board.
2556 - CONFIG_SYS_CONSOLE_INFO_QUIET
2557 Suppress display of console information at boot.
2559 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2560 If the board specific function
2561 extern int overwrite_console (void);
2562 returns 1, the stdin, stderr and stdout are switched to the
2563 serial port, else the settings in the environment are used.
2565 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2566 Enable the call to overwrite_console().
2568 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2569 Enable overwrite of previous console environment settings.
2571 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2572 Begin and End addresses of the area used by the
2575 - CONFIG_SYS_ALT_MEMTEST:
2576 Enable an alternate, more extensive memory test.
2578 - CONFIG_SYS_MEMTEST_SCRATCH:
2579 Scratch address used by the alternate memory test
2580 You only need to set this if address zero isn't writeable
2582 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2583 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2584 this specified memory area will get subtracted from the top
2585 (end) of RAM and won't get "touched" at all by U-Boot. By
2586 fixing up gd->ram_size the Linux kernel should gets passed
2587 the now "corrected" memory size and won't touch it either.
2588 This should work for arch/ppc and arch/powerpc. Only Linux
2589 board ports in arch/powerpc with bootwrapper support that
2590 recalculate the memory size from the SDRAM controller setup
2591 will have to get fixed in Linux additionally.
2593 This option can be used as a workaround for the 440EPx/GRx
2594 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2597 WARNING: Please make sure that this value is a multiple of
2598 the Linux page size (normally 4k). If this is not the case,
2599 then the end address of the Linux memory will be located at a
2600 non page size aligned address and this could cause major
2603 - CONFIG_SYS_TFTP_LOADADDR:
2604 Default load address for network file downloads
2606 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2607 Enable temporary baudrate change while serial download
2609 - CONFIG_SYS_SDRAM_BASE:
2610 Physical start address of SDRAM. _Must_ be 0 here.
2612 - CONFIG_SYS_MBIO_BASE:
2613 Physical start address of Motherboard I/O (if using a
2616 - CONFIG_SYS_FLASH_BASE:
2617 Physical start address of Flash memory.
2619 - CONFIG_SYS_MONITOR_BASE:
2620 Physical start address of boot monitor code (set by
2621 make config files to be same as the text base address
2622 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2623 CONFIG_SYS_FLASH_BASE when booting from flash.
2625 - CONFIG_SYS_MONITOR_LEN:
2626 Size of memory reserved for monitor code, used to
2627 determine _at_compile_time_ (!) if the environment is
2628 embedded within the U-Boot image, or in a separate
2631 - CONFIG_SYS_MALLOC_LEN:
2632 Size of DRAM reserved for malloc() use.
2634 - CONFIG_SYS_BOOTM_LEN:
2635 Normally compressed uImages are limited to an
2636 uncompressed size of 8 MBytes. If this is not enough,
2637 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2638 to adjust this setting to your needs.
2640 - CONFIG_SYS_BOOTMAPSZ:
2641 Maximum size of memory mapped by the startup code of
2642 the Linux kernel; all data that must be processed by
2643 the Linux kernel (bd_info, boot arguments, FDT blob if
2644 used) must be put below this limit, unless "bootm_low"
2645 enviroment variable is defined and non-zero. In such case
2646 all data for the Linux kernel must be between "bootm_low"
2647 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2648 variable "bootm_mapsize" will override the value of
2649 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2650 then the value in "bootm_size" will be used instead.
2652 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2653 Enable initrd_high functionality. If defined then the
2654 initrd_high feature is enabled and the bootm ramdisk subcommand
2657 - CONFIG_SYS_BOOT_GET_CMDLINE:
2658 Enables allocating and saving kernel cmdline in space between
2659 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2661 - CONFIG_SYS_BOOT_GET_KBD:
2662 Enables allocating and saving a kernel copy of the bd_info in
2663 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2665 - CONFIG_SYS_MAX_FLASH_BANKS:
2666 Max number of Flash memory banks
2668 - CONFIG_SYS_MAX_FLASH_SECT:
2669 Max number of sectors on a Flash chip
2671 - CONFIG_SYS_FLASH_ERASE_TOUT:
2672 Timeout for Flash erase operations (in ms)
2674 - CONFIG_SYS_FLASH_WRITE_TOUT:
2675 Timeout for Flash write operations (in ms)
2677 - CONFIG_SYS_FLASH_LOCK_TOUT
2678 Timeout for Flash set sector lock bit operation (in ms)
2680 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2681 Timeout for Flash clear lock bits operation (in ms)
2683 - CONFIG_SYS_FLASH_PROTECTION
2684 If defined, hardware flash sectors protection is used
2685 instead of U-Boot software protection.
2687 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2689 Enable TFTP transfers directly to flash memory;
2690 without this option such a download has to be
2691 performed in two steps: (1) download to RAM, and (2)
2692 copy from RAM to flash.
2694 The two-step approach is usually more reliable, since
2695 you can check if the download worked before you erase
2696 the flash, but in some situations (when system RAM is
2697 too limited to allow for a temporary copy of the
2698 downloaded image) this option may be very useful.
2700 - CONFIG_SYS_FLASH_CFI:
2701 Define if the flash driver uses extra elements in the
2702 common flash structure for storing flash geometry.
2704 - CONFIG_FLASH_CFI_DRIVER
2705 This option also enables the building of the cfi_flash driver
2706 in the drivers directory
2708 - CONFIG_FLASH_CFI_MTD
2709 This option enables the building of the cfi_mtd driver
2710 in the drivers directory. The driver exports CFI flash
2713 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2714 Use buffered writes to flash.
2716 - CONFIG_FLASH_SPANSION_S29WS_N
2717 s29ws-n MirrorBit flash has non-standard addresses for buffered
2720 - CONFIG_SYS_FLASH_QUIET_TEST
2721 If this option is defined, the common CFI flash doesn't
2722 print it's warning upon not recognized FLASH banks. This
2723 is useful, if some of the configured banks are only
2724 optionally available.
2726 - CONFIG_FLASH_SHOW_PROGRESS
2727 If defined (must be an integer), print out countdown
2728 digits and dots. Recommended value: 45 (9..1) for 80
2729 column displays, 15 (3..1) for 40 column displays.
2731 - CONFIG_SYS_RX_ETH_BUFFER:
2732 Defines the number of Ethernet receive buffers. On some
2733 Ethernet controllers it is recommended to set this value
2734 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2735 buffers can be full shortly after enabling the interface
2736 on high Ethernet traffic.
2737 Defaults to 4 if not defined.
2739 - CONFIG_ENV_MAX_ENTRIES
2741 Maximum number of entries in the hash table that is used
2742 internally to store the environment settings. The default
2743 setting is supposed to be generous and should work in most
2744 cases. This setting can be used to tune behaviour; see
2745 lib/hashtable.c for details.
2747 The following definitions that deal with the placement and management
2748 of environment data (variable area); in general, we support the
2749 following configurations:
2751 - CONFIG_BUILD_ENVCRC:
2753 Builds up envcrc with the target environment so that external utils
2754 may easily extract it and embed it in final U-Boot images.
2756 - CONFIG_ENV_IS_IN_FLASH:
2758 Define this if the environment is in flash memory.
2760 a) The environment occupies one whole flash sector, which is
2761 "embedded" in the text segment with the U-Boot code. This
2762 happens usually with "bottom boot sector" or "top boot
2763 sector" type flash chips, which have several smaller
2764 sectors at the start or the end. For instance, such a
2765 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2766 such a case you would place the environment in one of the
2767 4 kB sectors - with U-Boot code before and after it. With
2768 "top boot sector" type flash chips, you would put the
2769 environment in one of the last sectors, leaving a gap
2770 between U-Boot and the environment.
2772 - CONFIG_ENV_OFFSET:
2774 Offset of environment data (variable area) to the
2775 beginning of flash memory; for instance, with bottom boot
2776 type flash chips the second sector can be used: the offset
2777 for this sector is given here.
2779 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2783 This is just another way to specify the start address of
2784 the flash sector containing the environment (instead of
2787 - CONFIG_ENV_SECT_SIZE:
2789 Size of the sector containing the environment.
2792 b) Sometimes flash chips have few, equal sized, BIG sectors.
2793 In such a case you don't want to spend a whole sector for
2798 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2799 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2800 of this flash sector for the environment. This saves
2801 memory for the RAM copy of the environment.
2803 It may also save flash memory if you decide to use this
2804 when your environment is "embedded" within U-Boot code,
2805 since then the remainder of the flash sector could be used
2806 for U-Boot code. It should be pointed out that this is
2807 STRONGLY DISCOURAGED from a robustness point of view:
2808 updating the environment in flash makes it always
2809 necessary to erase the WHOLE sector. If something goes
2810 wrong before the contents has been restored from a copy in
2811 RAM, your target system will be dead.
2813 - CONFIG_ENV_ADDR_REDUND
2814 CONFIG_ENV_SIZE_REDUND
2816 These settings describe a second storage area used to hold
2817 a redundant copy of the environment data, so that there is
2818 a valid backup copy in case there is a power failure during
2819 a "saveenv" operation.
2821 BE CAREFUL! Any changes to the flash layout, and some changes to the
2822 source code will make it necessary to adapt <board>/u-boot.lds*
2826 - CONFIG_ENV_IS_IN_NVRAM:
2828 Define this if you have some non-volatile memory device
2829 (NVRAM, battery buffered SRAM) which you want to use for the
2835 These two #defines are used to determine the memory area you
2836 want to use for environment. It is assumed that this memory
2837 can just be read and written to, without any special
2840 BE CAREFUL! The first access to the environment happens quite early
2841 in U-Boot initalization (when we try to get the setting of for the
2842 console baudrate). You *MUST* have mapped your NVRAM area then, or
2845 Please note that even with NVRAM we still use a copy of the
2846 environment in RAM: we could work on NVRAM directly, but we want to
2847 keep settings there always unmodified except somebody uses "saveenv"
2848 to save the current settings.
2851 - CONFIG_ENV_IS_IN_EEPROM:
2853 Use this if you have an EEPROM or similar serial access
2854 device and a driver for it.
2856 - CONFIG_ENV_OFFSET:
2859 These two #defines specify the offset and size of the
2860 environment area within the total memory of your EEPROM.
2862 - CONFIG_SYS_I2C_EEPROM_ADDR:
2863 If defined, specified the chip address of the EEPROM device.
2864 The default address is zero.
2866 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2867 If defined, the number of bits used to address bytes in a
2868 single page in the EEPROM device. A 64 byte page, for example
2869 would require six bits.
2871 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2872 If defined, the number of milliseconds to delay between
2873 page writes. The default is zero milliseconds.
2875 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2876 The length in bytes of the EEPROM memory array address. Note
2877 that this is NOT the chip address length!
2879 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2880 EEPROM chips that implement "address overflow" are ones
2881 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2882 address and the extra bits end up in the "chip address" bit
2883 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2886 Note that we consider the length of the address field to
2887 still be one byte because the extra address bits are hidden
2888 in the chip address.
2890 - CONFIG_SYS_EEPROM_SIZE:
2891 The size in bytes of the EEPROM device.
2893 - CONFIG_ENV_EEPROM_IS_ON_I2C
2894 define this, if you have I2C and SPI activated, and your
2895 EEPROM, which holds the environment, is on the I2C bus.
2897 - CONFIG_I2C_ENV_EEPROM_BUS
2898 if you have an Environment on an EEPROM reached over
2899 I2C muxes, you can define here, how to reach this
2900 EEPROM. For example:
2902 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2904 EEPROM which holds the environment, is reached over
2905 a pca9547 i2c mux with address 0x70, channel 3.
2907 - CONFIG_ENV_IS_IN_DATAFLASH:
2909 Define this if you have a DataFlash memory device which you
2910 want to use for the environment.
2912 - CONFIG_ENV_OFFSET:
2916 These three #defines specify the offset and size of the
2917 environment area within the total memory of your DataFlash placed
2918 at the specified address.
2920 - CONFIG_ENV_IS_IN_NAND:
2922 Define this if you have a NAND device which you want to use
2923 for the environment.
2925 - CONFIG_ENV_OFFSET:
2928 These two #defines specify the offset and size of the environment
2929 area within the first NAND device. CONFIG_ENV_OFFSET must be
2930 aligned to an erase block boundary.
2932 - CONFIG_ENV_OFFSET_REDUND (optional):
2934 This setting describes a second storage area of CONFIG_ENV_SIZE
2935 size used to hold a redundant copy of the environment data, so
2936 that there is a valid backup copy in case there is a power failure
2937 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2938 aligned to an erase block boundary.
2940 - CONFIG_ENV_RANGE (optional):
2942 Specifies the length of the region in which the environment
2943 can be written. This should be a multiple of the NAND device's
2944 block size. Specifying a range with more erase blocks than
2945 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2946 the range to be avoided.
2948 - CONFIG_ENV_OFFSET_OOB (optional):
2950 Enables support for dynamically retrieving the offset of the
2951 environment from block zero's out-of-band data. The
2952 "nand env.oob" command can be used to record this offset.
2953 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2954 using CONFIG_ENV_OFFSET_OOB.
2956 - CONFIG_NAND_ENV_DST
2958 Defines address in RAM to which the nand_spl code should copy the
2959 environment. If redundant environment is used, it will be copied to
2960 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2962 - CONFIG_SYS_SPI_INIT_OFFSET
2964 Defines offset to the initial SPI buffer area in DPRAM. The
2965 area is used at an early stage (ROM part) if the environment
2966 is configured to reside in the SPI EEPROM: We need a 520 byte
2967 scratch DPRAM area. It is used between the two initialization
2968 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2969 to be a good choice since it makes it far enough from the
2970 start of the data area as well as from the stack pointer.
2972 Please note that the environment is read-only until the monitor
2973 has been relocated to RAM and a RAM copy of the environment has been
2974 created; also, when using EEPROM you will have to use getenv_f()
2975 until then to read environment variables.
2977 The environment is protected by a CRC32 checksum. Before the monitor
2978 is relocated into RAM, as a result of a bad CRC you will be working
2979 with the compiled-in default environment - *silently*!!! [This is
2980 necessary, because the first environment variable we need is the
2981 "baudrate" setting for the console - if we have a bad CRC, we don't
2982 have any device yet where we could complain.]
2984 Note: once the monitor has been relocated, then it will complain if
2985 the default environment is used; a new CRC is computed as soon as you
2986 use the "saveenv" command to store a valid environment.
2988 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2989 Echo the inverted Ethernet link state to the fault LED.
2991 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2992 also needs to be defined.
2994 - CONFIG_SYS_FAULT_MII_ADDR:
2995 MII address of the PHY to check for the Ethernet link state.
2997 - CONFIG_NS16550_MIN_FUNCTIONS:
2998 Define this if you desire to only have use of the NS16550_init
2999 and NS16550_putc functions for the serial driver located at
3000 drivers/serial/ns16550.c. This option is useful for saving
3001 space for already greatly restricted images, including but not
3002 limited to NAND_SPL configurations.
3004 Low Level (hardware related) configuration options:
3005 ---------------------------------------------------
3007 - CONFIG_SYS_CACHELINE_SIZE:
3008 Cache Line Size of the CPU.
3010 - CONFIG_SYS_DEFAULT_IMMR:
3011 Default address of the IMMR after system reset.
3013 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3014 and RPXsuper) to be able to adjust the position of
3015 the IMMR register after a reset.
3017 - CONFIG_SYS_CCSRBAR_DEFAULT:
3018 Default (power-on reset) physical address of CCSR on Freescale
3021 - CONFIG_SYS_CCSRBAR:
3022 Virtual address of CCSR. On a 32-bit build, this is typically
3023 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3025 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3026 for cross-platform code that uses that macro instead.
3028 - CONFIG_SYS_CCSRBAR_PHYS:
3029 Physical address of CCSR. CCSR can be relocated to a new
3030 physical address, if desired. In this case, this macro should
3031 be set to that address. Otherwise, it should be set to the
3032 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3033 is typically relocated on 36-bit builds. It is recommended
3034 that this macro be defined via the _HIGH and _LOW macros:
3036 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3037 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3039 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3040 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3041 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3042 used in assembly code, so it must not contain typecasts or
3043 integer size suffixes (e.g. "ULL").
3045 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3046 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3047 used in assembly code, so it must not contain typecasts or
3048 integer size suffixes (e.g. "ULL").
3050 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3051 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3052 forced to a value that ensures that CCSR is not relocated.
3054 - Floppy Disk Support:
3055 CONFIG_SYS_FDC_DRIVE_NUMBER
3057 the default drive number (default value 0)
3059 CONFIG_SYS_ISA_IO_STRIDE
3061 defines the spacing between FDC chipset registers
3064 CONFIG_SYS_ISA_IO_OFFSET
3066 defines the offset of register from address. It
3067 depends on which part of the data bus is connected to
3068 the FDC chipset. (default value 0)
3070 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3071 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3074 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3075 fdc_hw_init() is called at the beginning of the FDC
3076 setup. fdc_hw_init() must be provided by the board
3077 source code. It is used to make hardware dependant
3081 Most IDE controllers were designed to be connected with PCI
3082 interface. Only few of them were designed for AHB interface.
3083 When software is doing ATA command and data transfer to
3084 IDE devices through IDE-AHB controller, some additional
3085 registers accessing to these kind of IDE-AHB controller
3088 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3089 DO NOT CHANGE unless you know exactly what you're
3090 doing! (11-4) [MPC8xx/82xx systems only]
3092 - CONFIG_SYS_INIT_RAM_ADDR:
3094 Start address of memory area that can be used for
3095 initial data and stack; please note that this must be
3096 writable memory that is working WITHOUT special
3097 initialization, i. e. you CANNOT use normal RAM which
3098 will become available only after programming the
3099 memory controller and running certain initialization
3102 U-Boot uses the following memory types:
3103 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3104 - MPC824X: data cache
3105 - PPC4xx: data cache
3107 - CONFIG_SYS_GBL_DATA_OFFSET:
3109 Offset of the initial data structure in the memory
3110 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3111 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3112 data is located at the end of the available space
3113 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3114 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3115 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3116 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3119 On the MPC824X (or other systems that use the data
3120 cache for initial memory) the address chosen for
3121 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3122 point to an otherwise UNUSED address space between
3123 the top of RAM and the start of the PCI space.
3125 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3127 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3129 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3131 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3133 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3135 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3137 - CONFIG_SYS_OR_TIMING_SDRAM:
3140 - CONFIG_SYS_MAMR_PTA:
3141 periodic timer for refresh
3143 - CONFIG_SYS_DER: Debug Event Register (37-47)
3145 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3146 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3147 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3148 CONFIG_SYS_BR1_PRELIM:
3149 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3151 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3152 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3153 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3154 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3156 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3157 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3158 Machine Mode Register and Memory Periodic Timer
3159 Prescaler definitions (SDRAM timing)
3161 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3162 enable I2C microcode relocation patch (MPC8xx);
3163 define relocation offset in DPRAM [DSP2]
3165 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3166 enable SMC microcode relocation patch (MPC8xx);
3167 define relocation offset in DPRAM [SMC1]
3169 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3170 enable SPI microcode relocation patch (MPC8xx);
3171 define relocation offset in DPRAM [SCC4]
3173 - CONFIG_SYS_USE_OSCCLK:
3174 Use OSCM clock mode on MBX8xx board. Be careful,
3175 wrong setting might damage your board. Read
3176 doc/README.MBX before setting this variable!
3178 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3179 Offset of the bootmode word in DPRAM used by post
3180 (Power On Self Tests). This definition overrides
3181 #define'd default value in commproc.h resp.
3184 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3185 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3186 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3187 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3188 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3189 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3190 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3191 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3192 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3194 - CONFIG_PCI_DISABLE_PCIE:
3195 Disable PCI-Express on systems where it is supported but not
3199 Chip has SRIO or not
3202 Board has SRIO 1 port available
3205 Board has SRIO 2 port available
3207 - CONFIG_SYS_SRIOn_MEM_VIRT:
3208 Virtual Address of SRIO port 'n' memory region
3210 - CONFIG_SYS_SRIOn_MEM_PHYS:
3211 Physical Address of SRIO port 'n' memory region
3213 - CONFIG_SYS_SRIOn_MEM_SIZE:
3214 Size of SRIO port 'n' memory region
3216 - CONFIG_SYS_NDFC_16
3217 Defined to tell the NDFC that the NAND chip is using a
3220 - CONFIG_SYS_NDFC_EBC0_CFG
3221 Sets the EBC0_CFG register for the NDFC. If not defined
3222 a default value will be used.
3225 Get DDR timing information from an I2C EEPROM. Common
3226 with pluggable memory modules such as SODIMMs
3229 I2C address of the SPD EEPROM
3231 - CONFIG_SYS_SPD_BUS_NUM
3232 If SPD EEPROM is on an I2C bus other than the first
3233 one, specify here. Note that the value must resolve
3234 to something your driver can deal with.
3236 - CONFIG_SYS_DDR_RAW_TIMING
3237 Get DDR timing information from other than SPD. Common with
3238 soldered DDR chips onboard without SPD. DDR raw timing
3239 parameters are extracted from datasheet and hard-coded into
3240 header files or board specific files.
3242 - CONFIG_FSL_DDR_INTERACTIVE
3243 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3245 - CONFIG_SYS_83XX_DDR_USES_CS0
3246 Only for 83xx systems. If specified, then DDR should
3247 be configured using CS0 and CS1 instead of CS2 and CS3.
3249 - CONFIG_ETHER_ON_FEC[12]
3250 Define to enable FEC[12] on a 8xx series processor.
3252 - CONFIG_FEC[12]_PHY
3253 Define to the hardcoded PHY address which corresponds
3254 to the given FEC; i. e.
3255 #define CONFIG_FEC1_PHY 4
3256 means that the PHY with address 4 is connected to FEC1
3258 When set to -1, means to probe for first available.
3260 - CONFIG_FEC[12]_PHY_NORXERR
3261 The PHY does not have a RXERR line (RMII only).
3262 (so program the FEC to ignore it).
3265 Enable RMII mode for all FECs.
3266 Note that this is a global option, we can't
3267 have one FEC in standard MII mode and another in RMII mode.
3269 - CONFIG_CRC32_VERIFY
3270 Add a verify option to the crc32 command.
3273 => crc32 -v <address> <count> <crc32>
3275 Where address/count indicate a memory area
3276 and crc32 is the correct crc32 which the
3280 Add the "loopw" memory command. This only takes effect if
3281 the memory commands are activated globally (CONFIG_CMD_MEM).
3284 Add the "mdc" and "mwc" memory commands. These are cyclic
3289 This command will print 4 bytes (10,11,12,13) each 500 ms.
3291 => mwc.l 100 12345678 10
3292 This command will write 12345678 to address 100 all 10 ms.
3294 This only takes effect if the memory commands are activated
3295 globally (CONFIG_CMD_MEM).
3297 - CONFIG_SKIP_LOWLEVEL_INIT
3298 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3299 low level initializations (like setting up the memory
3300 controller) are omitted and/or U-Boot does not
3301 relocate itself into RAM.
3303 Normally this variable MUST NOT be defined. The only
3304 exception is when U-Boot is loaded (to RAM) by some
3305 other boot loader or by a debugger which performs
3306 these initializations itself.
3309 Modifies the behaviour of start.S when compiling a loader
3310 that is executed before the actual U-Boot. E.g. when
3311 compiling a NAND SPL.
3313 - CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3314 define this, if you want to read first the oob data
3315 and then the data. This is used for example on
3318 - CONFIG_USE_ARCH_MEMCPY
3319 CONFIG_USE_ARCH_MEMSET
3320 If these options are used a optimized version of memcpy/memset will
3321 be used if available. These functions may be faster under some
3322 conditions but may increase the binary size.
3324 Freescale QE/FMAN Firmware Support:
3325 -----------------------------------
3327 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3328 loading of "firmware", which is encoded in the QE firmware binary format.
3329 This firmware often needs to be loaded during U-Boot booting, so macros
3330 are used to identify the storage device (NOR flash, SPI, etc) and the address
3333 - CONFIG_SYS_QE_FMAN_FW_ADDR
3334 The address in the storage device where the firmware is located. The
3335 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3338 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3339 The maximum possible size of the firmware. The firmware binary format
3340 has a field that specifies the actual size of the firmware, but it
3341 might not be possible to read any part of the firmware unless some
3342 local storage is allocated to hold the entire firmware first.
3344 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3345 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3346 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3347 virtual address in NOR flash.
3349 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3350 Specifies that QE/FMAN firmware is located in NAND flash.
3351 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3353 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3354 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3355 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3357 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3358 Specifies that QE/FMAN firmware is located on the primary SPI
3359 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3362 Building the Software:
3363 ======================
3365 Building U-Boot has been tested in several native build environments
3366 and in many different cross environments. Of course we cannot support
3367 all possibly existing versions of cross development tools in all
3368 (potentially obsolete) versions. In case of tool chain problems we
3369 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3370 which is extensively used to build and test U-Boot.
3372 If you are not using a native environment, it is assumed that you
3373 have GNU cross compiling tools available in your path. In this case,
3374 you must set the environment variable CROSS_COMPILE in your shell.
3375 Note that no changes to the Makefile or any other source files are
3376 necessary. For example using the ELDK on a 4xx CPU, please enter:
3378 $ CROSS_COMPILE=ppc_4xx-
3379 $ export CROSS_COMPILE
3381 Note: If you wish to generate Windows versions of the utilities in
3382 the tools directory you can use the MinGW toolchain
3383 (http://www.mingw.org). Set your HOST tools to the MinGW
3384 toolchain and execute 'make tools'. For example:
3386 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3388 Binaries such as tools/mkimage.exe will be created which can
3389 be executed on computers running Windows.
3391 U-Boot is intended to be simple to build. After installing the
3392 sources you must configure U-Boot for one specific board type. This
3397 where "NAME_config" is the name of one of the existing configu-
3398 rations; see the main Makefile for supported names.
3400 Note: for some board special configuration names may exist; check if
3401 additional information is available from the board vendor; for
3402 instance, the TQM823L systems are available without (standard)
3403 or with LCD support. You can select such additional "features"
3404 when choosing the configuration, i. e.
3407 - will configure for a plain TQM823L, i. e. no LCD support
3409 make TQM823L_LCD_config
3410 - will configure for a TQM823L with U-Boot console on LCD
3415 Finally, type "make all", and you should get some working U-Boot
3416 images ready for download to / installation on your system:
3418 - "u-boot.bin" is a raw binary image
3419 - "u-boot" is an image in ELF binary format
3420 - "u-boot.srec" is in Motorola S-Record format
3422 By default the build is performed locally and the objects are saved
3423 in the source directory. One of the two methods can be used to change
3424 this behavior and build U-Boot to some external directory:
3426 1. Add O= to the make command line invocations:
3428 make O=/tmp/build distclean
3429 make O=/tmp/build NAME_config
3430 make O=/tmp/build all
3432 2. Set environment variable BUILD_DIR to point to the desired location:
3434 export BUILD_DIR=/tmp/build
3439 Note that the command line "O=" setting overrides the BUILD_DIR environment
3443 Please be aware that the Makefiles assume you are using GNU make, so
3444 for instance on NetBSD you might need to use "gmake" instead of
3448 If the system board that you have is not listed, then you will need
3449 to port U-Boot to your hardware platform. To do this, follow these
3452 1. Add a new configuration option for your board to the toplevel
3453 "Makefile" and to the "MAKEALL" script, using the existing
3454 entries as examples. Note that here and at many other places
3455 boards and other names are listed in alphabetical sort order. Please
3457 2. Create a new directory to hold your board specific code. Add any
3458 files you need. In your board directory, you will need at least
3459 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3460 3. Create a new configuration file "include/configs/<board>.h" for
3462 3. If you're porting U-Boot to a new CPU, then also create a new
3463 directory to hold your CPU specific code. Add any files you need.
3464 4. Run "make <board>_config" with your new name.
3465 5. Type "make", and you should get a working "u-boot.srec" file
3466 to be installed on your target system.
3467 6. Debug and solve any problems that might arise.
3468 [Of course, this last step is much harder than it sounds.]
3471 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3472 ==============================================================
3474 If you have modified U-Boot sources (for instance added a new board
3475 or support for new devices, a new CPU, etc.) you are expected to
3476 provide feedback to the other developers. The feedback normally takes
3477 the form of a "patch", i. e. a context diff against a certain (latest
3478 official or latest in the git repository) version of U-Boot sources.
3480 But before you submit such a patch, please verify that your modifi-
3481 cation did not break existing code. At least make sure that *ALL* of
3482 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3483 just run the "MAKEALL" script, which will configure and build U-Boot
3484 for ALL supported system. Be warned, this will take a while. You can
3485 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3486 environment variable to the script, i. e. to use the ELDK cross tools
3489 CROSS_COMPILE=ppc_8xx- MAKEALL
3491 or to build on a native PowerPC system you can type
3493 CROSS_COMPILE=' ' MAKEALL
3495 When using the MAKEALL script, the default behaviour is to build
3496 U-Boot in the source directory. This location can be changed by
3497 setting the BUILD_DIR environment variable. Also, for each target
3498 built, the MAKEALL script saves two log files (<target>.ERR and
3499 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3500 location can be changed by setting the MAKEALL_LOGDIR environment
3501 variable. For example:
3503 export BUILD_DIR=/tmp/build
3504 export MAKEALL_LOGDIR=/tmp/log
3505 CROSS_COMPILE=ppc_8xx- MAKEALL
3507 With the above settings build objects are saved in the /tmp/build,
3508 log files are saved in the /tmp/log and the source tree remains clean
3509 during the whole build process.
3512 See also "U-Boot Porting Guide" below.
3515 Monitor Commands - Overview:
3516 ============================
3518 go - start application at address 'addr'
3519 run - run commands in an environment variable
3520 bootm - boot application image from memory
3521 bootp - boot image via network using BootP/TFTP protocol
3522 tftpboot- boot image via network using TFTP protocol
3523 and env variables "ipaddr" and "serverip"
3524 (and eventually "gatewayip")
3525 tftpput - upload a file via network using TFTP protocol
3526 rarpboot- boot image via network using RARP/TFTP protocol
3527 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3528 loads - load S-Record file over serial line
3529 loadb - load binary file over serial line (kermit mode)
3531 mm - memory modify (auto-incrementing)
3532 nm - memory modify (constant address)
3533 mw - memory write (fill)
3535 cmp - memory compare
3536 crc32 - checksum calculation
3537 i2c - I2C sub-system
3538 sspi - SPI utility commands
3539 base - print or set address offset
3540 printenv- print environment variables
3541 setenv - set environment variables
3542 saveenv - save environment variables to persistent storage
3543 protect - enable or disable FLASH write protection
3544 erase - erase FLASH memory
3545 flinfo - print FLASH memory information
3546 bdinfo - print Board Info structure
3547 iminfo - print header information for application image
3548 coninfo - print console devices and informations
3549 ide - IDE sub-system
3550 loop - infinite loop on address range
3551 loopw - infinite write loop on address range
3552 mtest - simple RAM test
3553 icache - enable or disable instruction cache
3554 dcache - enable or disable data cache
3555 reset - Perform RESET of the CPU
3556 echo - echo args to console
3557 version - print monitor version
3558 help - print online help
3559 ? - alias for 'help'
3562 Monitor Commands - Detailed Description:
3563 ========================================
3567 For now: just type "help <command>".
3570 Environment Variables:
3571 ======================
3573 U-Boot supports user configuration using Environment Variables which
3574 can be made persistent by saving to Flash memory.
3576 Environment Variables are set using "setenv", printed using
3577 "printenv", and saved to Flash using "saveenv". Using "setenv"
3578 without a value can be used to delete a variable from the
3579 environment. As long as you don't save the environment you are
3580 working with an in-memory copy. In case the Flash area containing the
3581 environment is erased by accident, a default environment is provided.
3583 Some configuration options can be set using Environment Variables.
3585 List of environment variables (most likely not complete):
3587 baudrate - see CONFIG_BAUDRATE
3589 bootdelay - see CONFIG_BOOTDELAY
3591 bootcmd - see CONFIG_BOOTCOMMAND
3593 bootargs - Boot arguments when booting an RTOS image
3595 bootfile - Name of the image to load with TFTP
3597 bootm_low - Memory range available for image processing in the bootm
3598 command can be restricted. This variable is given as
3599 a hexadecimal number and defines lowest address allowed
3600 for use by the bootm command. See also "bootm_size"
3601 environment variable. Address defined by "bootm_low" is
3602 also the base of the initial memory mapping for the Linux
3603 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3606 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3607 This variable is given as a hexadecimal number and it
3608 defines the size of the memory region starting at base
3609 address bootm_low that is accessible by the Linux kernel
3610 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3611 as the default value if it is defined, and bootm_size is
3614 bootm_size - Memory range available for image processing in the bootm
3615 command can be restricted. This variable is given as
3616 a hexadecimal number and defines the size of the region
3617 allowed for use by the bootm command. See also "bootm_low"
3618 environment variable.
3620 updatefile - Location of the software update file on a TFTP server, used
3621 by the automatic software update feature. Please refer to
3622 documentation in doc/README.update for more details.
3624 autoload - if set to "no" (any string beginning with 'n'),
3625 "bootp" will just load perform a lookup of the
3626 configuration from the BOOTP server, but not try to
3627 load any image using TFTP
3629 autostart - if set to "yes", an image loaded using the "bootp",
3630 "rarpboot", "tftpboot" or "diskboot" commands will
3631 be automatically started (by internally calling
3634 If set to "no", a standalone image passed to the
3635 "bootm" command will be copied to the load address
3636 (and eventually uncompressed), but NOT be started.
3637 This can be used to load and uncompress arbitrary
3640 fdt_high - if set this restricts the maximum address that the
3641 flattened device tree will be copied into upon boot.
3642 If this is set to the special value 0xFFFFFFFF then
3643 the fdt will not be copied at all on boot. For this
3644 to work it must reside in writable memory, have
3645 sufficient padding on the end of it for u-boot to
3646 add the information it needs into it, and the memory
3647 must be accessible by the kernel.
3649 fdtcontroladdr- if set this is the address of the control flattened
3650 device tree used by U-Boot when CONFIG_OF_CONTROL is
3653 i2cfast - (PPC405GP|PPC405EP only)
3654 if set to 'y' configures Linux I2C driver for fast
3655 mode (400kHZ). This environment variable is used in
3656 initialization code. So, for changes to be effective
3657 it must be saved and board must be reset.
3659 initrd_high - restrict positioning of initrd images:
3660 If this variable is not set, initrd images will be
3661 copied to the highest possible address in RAM; this
3662 is usually what you want since it allows for
3663 maximum initrd size. If for some reason you want to
3664 make sure that the initrd image is loaded below the
3665 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3666 variable to a value of "no" or "off" or "0".
3667 Alternatively, you can set it to a maximum upper
3668 address to use (U-Boot will still check that it
3669 does not overwrite the U-Boot stack and data).
3671 For instance, when you have a system with 16 MB
3672 RAM, and want to reserve 4 MB from use by Linux,
3673 you can do this by adding "mem=12M" to the value of
3674 the "bootargs" variable. However, now you must make
3675 sure that the initrd image is placed in the first
3676 12 MB as well - this can be done with
3678 setenv initrd_high 00c00000
3680 If you set initrd_high to 0xFFFFFFFF, this is an
3681 indication to U-Boot that all addresses are legal
3682 for the Linux kernel, including addresses in flash
3683 memory. In this case U-Boot will NOT COPY the
3684 ramdisk at all. This may be useful to reduce the
3685 boot time on your system, but requires that this
3686 feature is supported by your Linux kernel.
3688 ipaddr - IP address; needed for tftpboot command
3690 loadaddr - Default load address for commands like "bootp",
3691 "rarpboot", "tftpboot", "loadb" or "diskboot"
3693 loads_echo - see CONFIG_LOADS_ECHO
3695 serverip - TFTP server IP address; needed for tftpboot command
3697 bootretry - see CONFIG_BOOT_RETRY_TIME
3699 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3701 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3703 ethprime - controls which interface is used first.
3705 ethact - controls which interface is currently active.
3706 For example you can do the following
3708 => setenv ethact FEC
3709 => ping 192.168.0.1 # traffic sent on FEC
3710 => setenv ethact SCC
3711 => ping 10.0.0.1 # traffic sent on SCC
3713 ethrotate - When set to "no" U-Boot does not go through all
3714 available network interfaces.
3715 It just stays at the currently selected interface.
3717 netretry - When set to "no" each network operation will
3718 either succeed or fail without retrying.
3719 When set to "once" the network operation will
3720 fail when all the available network interfaces
3721 are tried once without success.
3722 Useful on scripts which control the retry operation
3725 npe_ucode - set load address for the NPE microcode
3727 tftpsrcport - If this is set, the value is used for TFTP's
3730 tftpdstport - If this is set, the value is used for TFTP's UDP
3731 destination port instead of the Well Know Port 69.
3733 tftpblocksize - Block size to use for TFTP transfers; if not set,
3734 we use the TFTP server's default block size
3736 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3737 seconds, minimum value is 1000 = 1 second). Defines
3738 when a packet is considered to be lost so it has to
3739 be retransmitted. The default is 5000 = 5 seconds.
3740 Lowering this value may make downloads succeed
3741 faster in networks with high packet loss rates or
3742 with unreliable TFTP servers.
3744 vlan - When set to a value < 4095 the traffic over
3745 Ethernet is encapsulated/received over 802.1q
3748 The following image location variables contain the location of images
3749 used in booting. The "Image" column gives the role of the image and is
3750 not an environment variable name. The other columns are environment
3751 variable names. "File Name" gives the name of the file on a TFTP
3752 server, "RAM Address" gives the location in RAM the image will be
3753 loaded to, and "Flash Location" gives the image's address in NOR
3754 flash or offset in NAND flash.
3756 *Note* - these variables don't have to be defined for all boards, some
3757 boards currenlty use other variables for these purposes, and some
3758 boards use these variables for other purposes.
3760 Image File Name RAM Address Flash Location
3761 ----- --------- ----------- --------------
3762 u-boot u-boot u-boot_addr_r u-boot_addr
3763 Linux kernel bootfile kernel_addr_r kernel_addr
3764 device tree blob fdtfile fdt_addr_r fdt_addr
3765 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3767 The following environment variables may be used and automatically
3768 updated by the network boot commands ("bootp" and "rarpboot"),
3769 depending the information provided by your boot server:
3771 bootfile - see above
3772 dnsip - IP address of your Domain Name Server
3773 dnsip2 - IP address of your secondary Domain Name Server
3774 gatewayip - IP address of the Gateway (Router) to use
3775 hostname - Target hostname
3777 netmask - Subnet Mask
3778 rootpath - Pathname of the root filesystem on the NFS server
3779 serverip - see above
3782 There are two special Environment Variables:
3784 serial# - contains hardware identification information such
3785 as type string and/or serial number
3786 ethaddr - Ethernet address
3788 These variables can be set only once (usually during manufacturing of
3789 the board). U-Boot refuses to delete or overwrite these variables
3790 once they have been set once.
3793 Further special Environment Variables:
3795 ver - Contains the U-Boot version string as printed
3796 with the "version" command. This variable is
3797 readonly (see CONFIG_VERSION_VARIABLE).
3800 Please note that changes to some configuration parameters may take
3801 only effect after the next boot (yes, that's just like Windoze :-).
3804 Command Line Parsing:
3805 =====================
3807 There are two different command line parsers available with U-Boot:
3808 the old "simple" one, and the much more powerful "hush" shell:
3810 Old, simple command line parser:
3811 --------------------------------
3813 - supports environment variables (through setenv / saveenv commands)
3814 - several commands on one line, separated by ';'
3815 - variable substitution using "... ${name} ..." syntax
3816 - special characters ('$', ';') can be escaped by prefixing with '\',
3818 setenv bootcmd bootm \${address}
3819 - You can also escape text by enclosing in single apostrophes, for example:
3820 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3825 - similar to Bourne shell, with control structures like
3826 if...then...else...fi, for...do...done; while...do...done,
3827 until...do...done, ...
3828 - supports environment ("global") variables (through setenv / saveenv
3829 commands) and local shell variables (through standard shell syntax
3830 "name=value"); only environment variables can be used with "run"
3836 (1) If a command line (or an environment variable executed by a "run"
3837 command) contains several commands separated by semicolon, and
3838 one of these commands fails, then the remaining commands will be
3841 (2) If you execute several variables with one call to run (i. e.
3842 calling run with a list of variables as arguments), any failing
3843 command will cause "run" to terminate, i. e. the remaining
3844 variables are not executed.
3846 Note for Redundant Ethernet Interfaces:
3847 =======================================
3849 Some boards come with redundant Ethernet interfaces; U-Boot supports
3850 such configurations and is capable of automatic selection of a
3851 "working" interface when needed. MAC assignment works as follows:
3853 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3854 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3855 "eth1addr" (=>eth1), "eth2addr", ...
3857 If the network interface stores some valid MAC address (for instance
3858 in SROM), this is used as default address if there is NO correspon-
3859 ding setting in the environment; if the corresponding environment
3860 variable is set, this overrides the settings in the card; that means:
3862 o If the SROM has a valid MAC address, and there is no address in the
3863 environment, the SROM's address is used.
3865 o If there is no valid address in the SROM, and a definition in the
3866 environment exists, then the value from the environment variable is
3869 o If both the SROM and the environment contain a MAC address, and
3870 both addresses are the same, this MAC address is used.
3872 o If both the SROM and the environment contain a MAC address, and the
3873 addresses differ, the value from the environment is used and a
3876 o If neither SROM nor the environment contain a MAC address, an error
3879 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3880 will be programmed into hardware as part of the initialization process. This
3881 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3882 The naming convention is as follows:
3883 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3888 U-Boot is capable of booting (and performing other auxiliary operations on)
3889 images in two formats:
3891 New uImage format (FIT)
3892 -----------------------
3894 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3895 to Flattened Device Tree). It allows the use of images with multiple
3896 components (several kernels, ramdisks, etc.), with contents protected by
3897 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3903 Old image format is based on binary files which can be basically anything,
3904 preceded by a special header; see the definitions in include/image.h for
3905 details; basically, the header defines the following image properties:
3907 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3908 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3909 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3910 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3912 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3913 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3914 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3915 * Compression Type (uncompressed, gzip, bzip2)
3921 The header is marked by a special Magic Number, and both the header
3922 and the data portions of the image are secured against corruption by
3929 Although U-Boot should support any OS or standalone application
3930 easily, the main focus has always been on Linux during the design of
3933 U-Boot includes many features that so far have been part of some
3934 special "boot loader" code within the Linux kernel. Also, any
3935 "initrd" images to be used are no longer part of one big Linux image;
3936 instead, kernel and "initrd" are separate images. This implementation
3937 serves several purposes:
3939 - the same features can be used for other OS or standalone
3940 applications (for instance: using compressed images to reduce the
3941 Flash memory footprint)
3943 - it becomes much easier to port new Linux kernel versions because
3944 lots of low-level, hardware dependent stuff are done by U-Boot
3946 - the same Linux kernel image can now be used with different "initrd"
3947 images; of course this also means that different kernel images can
3948 be run with the same "initrd". This makes testing easier (you don't
3949 have to build a new "zImage.initrd" Linux image when you just
3950 change a file in your "initrd"). Also, a field-upgrade of the
3951 software is easier now.
3957 Porting Linux to U-Boot based systems:
3958 ---------------------------------------
3960 U-Boot cannot save you from doing all the necessary modifications to
3961 configure the Linux device drivers for use with your target hardware
3962 (no, we don't intend to provide a full virtual machine interface to
3965 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3967 Just make sure your machine specific header file (for instance
3968 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3969 Information structure as we define in include/asm-<arch>/u-boot.h,
3970 and make sure that your definition of IMAP_ADDR uses the same value
3971 as your U-Boot configuration in CONFIG_SYS_IMMR.
3974 Configuring the Linux kernel:
3975 -----------------------------
3977 No specific requirements for U-Boot. Make sure you have some root
3978 device (initial ramdisk, NFS) for your target system.
3981 Building a Linux Image:
3982 -----------------------
3984 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3985 not used. If you use recent kernel source, a new build target
3986 "uImage" will exist which automatically builds an image usable by
3987 U-Boot. Most older kernels also have support for a "pImage" target,
3988 which was introduced for our predecessor project PPCBoot and uses a
3989 100% compatible format.
3998 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3999 encapsulate a compressed Linux kernel image with header information,
4000 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4002 * build a standard "vmlinux" kernel image (in ELF binary format):
4004 * convert the kernel into a raw binary image:
4006 ${CROSS_COMPILE}-objcopy -O binary \
4007 -R .note -R .comment \
4008 -S vmlinux linux.bin
4010 * compress the binary image:
4014 * package compressed binary image for U-Boot:
4016 mkimage -A ppc -O linux -T kernel -C gzip \
4017 -a 0 -e 0 -n "Linux Kernel Image" \
4018 -d linux.bin.gz uImage
4021 The "mkimage" tool can also be used to create ramdisk images for use
4022 with U-Boot, either separated from the Linux kernel image, or
4023 combined into one file. "mkimage" encapsulates the images with a 64
4024 byte header containing information about target architecture,
4025 operating system, image type, compression method, entry points, time
4026 stamp, CRC32 checksums, etc.
4028 "mkimage" can be called in two ways: to verify existing images and
4029 print the header information, or to build new images.
4031 In the first form (with "-l" option) mkimage lists the information
4032 contained in the header of an existing U-Boot image; this includes
4033 checksum verification:
4035 tools/mkimage -l image
4036 -l ==> list image header information
4038 The second form (with "-d" option) is used to build a U-Boot image
4039 from a "data file" which is used as image payload:
4041 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4042 -n name -d data_file image
4043 -A ==> set architecture to 'arch'
4044 -O ==> set operating system to 'os'
4045 -T ==> set image type to 'type'
4046 -C ==> set compression type 'comp'
4047 -a ==> set load address to 'addr' (hex)
4048 -e ==> set entry point to 'ep' (hex)
4049 -n ==> set image name to 'name'
4050 -d ==> use image data from 'datafile'
4052 Right now, all Linux kernels for PowerPC systems use the same load
4053 address (0x00000000), but the entry point address depends on the
4056 - 2.2.x kernels have the entry point at 0x0000000C,
4057 - 2.3.x and later kernels have the entry point at 0x00000000.
4059 So a typical call to build a U-Boot image would read:
4061 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4062 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4063 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4064 > examples/uImage.TQM850L
4065 Image Name: 2.4.4 kernel for TQM850L
4066 Created: Wed Jul 19 02:34:59 2000
4067 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4068 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4069 Load Address: 0x00000000
4070 Entry Point: 0x00000000
4072 To verify the contents of the image (or check for corruption):
4074 -> tools/mkimage -l examples/uImage.TQM850L
4075 Image Name: 2.4.4 kernel for TQM850L
4076 Created: Wed Jul 19 02:34:59 2000
4077 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4078 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4079 Load Address: 0x00000000
4080 Entry Point: 0x00000000
4082 NOTE: for embedded systems where boot time is critical you can trade
4083 speed for memory and install an UNCOMPRESSED image instead: this
4084 needs more space in Flash, but boots much faster since it does not
4085 need to be uncompressed:
4087 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4088 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4089 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4090 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4091 > examples/uImage.TQM850L-uncompressed
4092 Image Name: 2.4.4 kernel for TQM850L
4093 Created: Wed Jul 19 02:34:59 2000
4094 Image Type: PowerPC Linux Kernel Image (uncompressed)
4095 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4096 Load Address: 0x00000000
4097 Entry Point: 0x00000000
4100 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4101 when your kernel is intended to use an initial ramdisk:
4103 -> tools/mkimage -n 'Simple Ramdisk Image' \
4104 > -A ppc -O linux -T ramdisk -C gzip \
4105 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4106 Image Name: Simple Ramdisk Image
4107 Created: Wed Jan 12 14:01:50 2000
4108 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4109 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4110 Load Address: 0x00000000
4111 Entry Point: 0x00000000
4114 Installing a Linux Image:
4115 -------------------------
4117 To downloading a U-Boot image over the serial (console) interface,
4118 you must convert the image to S-Record format:
4120 objcopy -I binary -O srec examples/image examples/image.srec
4122 The 'objcopy' does not understand the information in the U-Boot
4123 image header, so the resulting S-Record file will be relative to
4124 address 0x00000000. To load it to a given address, you need to
4125 specify the target address as 'offset' parameter with the 'loads'
4128 Example: install the image to address 0x40100000 (which on the
4129 TQM8xxL is in the first Flash bank):
4131 => erase 40100000 401FFFFF
4137 ## Ready for S-Record download ...
4138 ~>examples/image.srec
4139 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4141 15989 15990 15991 15992
4142 [file transfer complete]
4144 ## Start Addr = 0x00000000
4147 You can check the success of the download using the 'iminfo' command;
4148 this includes a checksum verification so you can be sure no data
4149 corruption happened:
4153 ## Checking Image at 40100000 ...
4154 Image Name: 2.2.13 for initrd on TQM850L
4155 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4156 Data Size: 335725 Bytes = 327 kB = 0 MB
4157 Load Address: 00000000
4158 Entry Point: 0000000c
4159 Verifying Checksum ... OK
4165 The "bootm" command is used to boot an application that is stored in
4166 memory (RAM or Flash). In case of a Linux kernel image, the contents
4167 of the "bootargs" environment variable is passed to the kernel as
4168 parameters. You can check and modify this variable using the
4169 "printenv" and "setenv" commands:
4172 => printenv bootargs
4173 bootargs=root=/dev/ram
4175 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4177 => printenv bootargs
4178 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4181 ## Booting Linux kernel at 40020000 ...
4182 Image Name: 2.2.13 for NFS on TQM850L
4183 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4184 Data Size: 381681 Bytes = 372 kB = 0 MB
4185 Load Address: 00000000
4186 Entry Point: 0000000c
4187 Verifying Checksum ... OK
4188 Uncompressing Kernel Image ... OK
4189 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
4190 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4191 time_init: decrementer frequency = 187500000/60
4192 Calibrating delay loop... 49.77 BogoMIPS
4193 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4196 If you want to boot a Linux kernel with initial RAM disk, you pass
4197 the memory addresses of both the kernel and the initrd image (PPBCOOT
4198 format!) to the "bootm" command:
4200 => imi 40100000 40200000
4202 ## Checking Image at 40100000 ...
4203 Image Name: 2.2.13 for initrd on TQM850L
4204 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4205 Data Size: 335725 Bytes = 327 kB = 0 MB
4206 Load Address: 00000000
4207 Entry Point: 0000000c
4208 Verifying Checksum ... OK
4210 ## Checking Image at 40200000 ...
4211 Image Name: Simple Ramdisk Image
4212 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4213 Data Size: 566530 Bytes = 553 kB = 0 MB
4214 Load Address: 00000000
4215 Entry Point: 00000000
4216 Verifying Checksum ... OK
4218 => bootm 40100000 40200000
4219 ## Booting Linux kernel at 40100000 ...
4220 Image Name: 2.2.13 for initrd on TQM850L
4221 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4222 Data Size: 335725 Bytes = 327 kB = 0 MB
4223 Load Address: 00000000
4224 Entry Point: 0000000c
4225 Verifying Checksum ... OK
4226 Uncompressing Kernel Image ... OK
4227 ## Loading RAMDisk Image at 40200000 ...
4228 Image Name: Simple Ramdisk Image
4229 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4230 Data Size: 566530 Bytes = 553 kB = 0 MB
4231 Load Address: 00000000
4232 Entry Point: 00000000
4233 Verifying Checksum ... OK
4234 Loading Ramdisk ... OK
4235 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
4236 Boot arguments: root=/dev/ram
4237 time_init: decrementer frequency = 187500000/60
4238 Calibrating delay loop... 49.77 BogoMIPS
4240 RAMDISK: Compressed image found at block 0
4241 VFS: Mounted root (ext2 filesystem).
4245 Boot Linux and pass a flat device tree:
4248 First, U-Boot must be compiled with the appropriate defines. See the section
4249 titled "Linux Kernel Interface" above for a more in depth explanation. The
4250 following is an example of how to start a kernel and pass an updated
4256 oft=oftrees/mpc8540ads.dtb
4257 => tftp $oftaddr $oft
4258 Speed: 1000, full duplex
4260 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4261 Filename 'oftrees/mpc8540ads.dtb'.
4262 Load address: 0x300000
4265 Bytes transferred = 4106 (100a hex)
4266 => tftp $loadaddr $bootfile
4267 Speed: 1000, full duplex
4269 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4271 Load address: 0x200000
4272 Loading:############
4274 Bytes transferred = 1029407 (fb51f hex)
4279 => bootm $loadaddr - $oftaddr
4280 ## Booting image at 00200000 ...
4281 Image Name: Linux-2.6.17-dirty
4282 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4283 Data Size: 1029343 Bytes = 1005.2 kB
4284 Load Address: 00000000
4285 Entry Point: 00000000
4286 Verifying Checksum ... OK
4287 Uncompressing Kernel Image ... OK
4288 Booting using flat device tree at 0x300000
4289 Using MPC85xx ADS machine description
4290 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4294 More About U-Boot Image Types:
4295 ------------------------------
4297 U-Boot supports the following image types:
4299 "Standalone Programs" are directly runnable in the environment
4300 provided by U-Boot; it is expected that (if they behave
4301 well) you can continue to work in U-Boot after return from
4302 the Standalone Program.
4303 "OS Kernel Images" are usually images of some Embedded OS which
4304 will take over control completely. Usually these programs
4305 will install their own set of exception handlers, device
4306 drivers, set up the MMU, etc. - this means, that you cannot
4307 expect to re-enter U-Boot except by resetting the CPU.
4308 "RAMDisk Images" are more or less just data blocks, and their
4309 parameters (address, size) are passed to an OS kernel that is
4311 "Multi-File Images" contain several images, typically an OS
4312 (Linux) kernel image and one or more data images like
4313 RAMDisks. This construct is useful for instance when you want
4314 to boot over the network using BOOTP etc., where the boot
4315 server provides just a single image file, but you want to get
4316 for instance an OS kernel and a RAMDisk image.
4318 "Multi-File Images" start with a list of image sizes, each
4319 image size (in bytes) specified by an "uint32_t" in network
4320 byte order. This list is terminated by an "(uint32_t)0".
4321 Immediately after the terminating 0 follow the images, one by
4322 one, all aligned on "uint32_t" boundaries (size rounded up to
4323 a multiple of 4 bytes).
4325 "Firmware Images" are binary images containing firmware (like
4326 U-Boot or FPGA images) which usually will be programmed to
4329 "Script files" are command sequences that will be executed by
4330 U-Boot's command interpreter; this feature is especially
4331 useful when you configure U-Boot to use a real shell (hush)
4332 as command interpreter.
4338 One of the features of U-Boot is that you can dynamically load and
4339 run "standalone" applications, which can use some resources of
4340 U-Boot like console I/O functions or interrupt services.
4342 Two simple examples are included with the sources:
4347 'examples/hello_world.c' contains a small "Hello World" Demo
4348 application; it is automatically compiled when you build U-Boot.
4349 It's configured to run at address 0x00040004, so you can play with it
4353 ## Ready for S-Record download ...
4354 ~>examples/hello_world.srec
4355 1 2 3 4 5 6 7 8 9 10 11 ...
4356 [file transfer complete]
4358 ## Start Addr = 0x00040004
4360 => go 40004 Hello World! This is a test.
4361 ## Starting application at 0x00040004 ...
4372 Hit any key to exit ...
4374 ## Application terminated, rc = 0x0
4376 Another example, which demonstrates how to register a CPM interrupt
4377 handler with the U-Boot code, can be found in 'examples/timer.c'.
4378 Here, a CPM timer is set up to generate an interrupt every second.
4379 The interrupt service routine is trivial, just printing a '.'
4380 character, but this is just a demo program. The application can be
4381 controlled by the following keys:
4383 ? - print current values og the CPM Timer registers
4384 b - enable interrupts and start timer
4385 e - stop timer and disable interrupts
4386 q - quit application
4389 ## Ready for S-Record download ...
4390 ~>examples/timer.srec
4391 1 2 3 4 5 6 7 8 9 10 11 ...
4392 [file transfer complete]
4394 ## Start Addr = 0x00040004
4397 ## Starting application at 0x00040004 ...
4400 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4403 [q, b, e, ?] Set interval 1000000 us
4406 [q, b, e, ?] ........
4407 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4410 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4413 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4416 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4418 [q, b, e, ?] ...Stopping timer
4420 [q, b, e, ?] ## Application terminated, rc = 0x0
4426 Over time, many people have reported problems when trying to use the
4427 "minicom" terminal emulation program for serial download. I (wd)
4428 consider minicom to be broken, and recommend not to use it. Under
4429 Unix, I recommend to use C-Kermit for general purpose use (and
4430 especially for kermit binary protocol download ("loadb" command), and
4431 use "cu" for S-Record download ("loads" command).
4433 Nevertheless, if you absolutely want to use it try adding this
4434 configuration to your "File transfer protocols" section:
4436 Name Program Name U/D FullScr IO-Red. Multi
4437 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4438 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4444 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4445 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4447 Building requires a cross environment; it is known to work on
4448 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4449 need gmake since the Makefiles are not compatible with BSD make).
4450 Note that the cross-powerpc package does not install include files;
4451 attempting to build U-Boot will fail because <machine/ansi.h> is
4452 missing. This file has to be installed and patched manually:
4454 # cd /usr/pkg/cross/powerpc-netbsd/include
4456 # ln -s powerpc machine
4457 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4458 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4460 Native builds *don't* work due to incompatibilities between native
4461 and U-Boot include files.
4463 Booting assumes that (the first part of) the image booted is a
4464 stage-2 loader which in turn loads and then invokes the kernel
4465 proper. Loader sources will eventually appear in the NetBSD source
4466 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4467 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4470 Implementation Internals:
4471 =========================
4473 The following is not intended to be a complete description of every
4474 implementation detail. However, it should help to understand the
4475 inner workings of U-Boot and make it easier to port it to custom
4479 Initial Stack, Global Data:
4480 ---------------------------
4482 The implementation of U-Boot is complicated by the fact that U-Boot
4483 starts running out of ROM (flash memory), usually without access to
4484 system RAM (because the memory controller is not initialized yet).
4485 This means that we don't have writable Data or BSS segments, and BSS
4486 is not initialized as zero. To be able to get a C environment working
4487 at all, we have to allocate at least a minimal stack. Implementation
4488 options for this are defined and restricted by the CPU used: Some CPU
4489 models provide on-chip memory (like the IMMR area on MPC8xx and
4490 MPC826x processors), on others (parts of) the data cache can be
4491 locked as (mis-) used as memory, etc.
4493 Chris Hallinan posted a good summary of these issues to the
4494 U-Boot mailing list:
4496 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4497 From: "Chris Hallinan" <clh@net1plus.com>
4498 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4501 Correct me if I'm wrong, folks, but the way I understand it
4502 is this: Using DCACHE as initial RAM for Stack, etc, does not
4503 require any physical RAM backing up the cache. The cleverness
4504 is that the cache is being used as a temporary supply of
4505 necessary storage before the SDRAM controller is setup. It's
4506 beyond the scope of this list to explain the details, but you
4507 can see how this works by studying the cache architecture and
4508 operation in the architecture and processor-specific manuals.
4510 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4511 is another option for the system designer to use as an
4512 initial stack/RAM area prior to SDRAM being available. Either
4513 option should work for you. Using CS 4 should be fine if your
4514 board designers haven't used it for something that would
4515 cause you grief during the initial boot! It is frequently not
4518 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4519 with your processor/board/system design. The default value
4520 you will find in any recent u-boot distribution in
4521 walnut.h should work for you. I'd set it to a value larger
4522 than your SDRAM module. If you have a 64MB SDRAM module, set
4523 it above 400_0000. Just make sure your board has no resources
4524 that are supposed to respond to that address! That code in
4525 start.S has been around a while and should work as is when
4526 you get the config right.
4531 It is essential to remember this, since it has some impact on the C
4532 code for the initialization procedures:
4534 * Initialized global data (data segment) is read-only. Do not attempt
4537 * Do not use any uninitialized global data (or implicitely initialized
4538 as zero data - BSS segment) at all - this is undefined, initiali-
4539 zation is performed later (when relocating to RAM).
4541 * Stack space is very limited. Avoid big data buffers or things like
4544 Having only the stack as writable memory limits means we cannot use
4545 normal global data to share information beween the code. But it
4546 turned out that the implementation of U-Boot can be greatly
4547 simplified by making a global data structure (gd_t) available to all
4548 functions. We could pass a pointer to this data as argument to _all_
4549 functions, but this would bloat the code. Instead we use a feature of
4550 the GCC compiler (Global Register Variables) to share the data: we
4551 place a pointer (gd) to the global data into a register which we
4552 reserve for this purpose.
4554 When choosing a register for such a purpose we are restricted by the
4555 relevant (E)ABI specifications for the current architecture, and by
4556 GCC's implementation.
4558 For PowerPC, the following registers have specific use:
4560 R2: reserved for system use
4561 R3-R4: parameter passing and return values
4562 R5-R10: parameter passing
4563 R13: small data area pointer
4567 (U-Boot also uses R12 as internal GOT pointer. r12
4568 is a volatile register so r12 needs to be reset when
4569 going back and forth between asm and C)
4571 ==> U-Boot will use R2 to hold a pointer to the global data
4573 Note: on PPC, we could use a static initializer (since the
4574 address of the global data structure is known at compile time),
4575 but it turned out that reserving a register results in somewhat
4576 smaller code - although the code savings are not that big (on
4577 average for all boards 752 bytes for the whole U-Boot image,
4578 624 text + 127 data).
4580 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4581 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4583 ==> U-Boot will use P3 to hold a pointer to the global data
4585 On ARM, the following registers are used:
4587 R0: function argument word/integer result
4588 R1-R3: function argument word
4590 R10: stack limit (used only if stack checking if enabled)
4591 R11: argument (frame) pointer
4592 R12: temporary workspace
4595 R15: program counter
4597 ==> U-Boot will use R8 to hold a pointer to the global data
4599 On Nios II, the ABI is documented here:
4600 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4602 ==> U-Boot will use gp to hold a pointer to the global data
4604 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4605 to access small data sections, so gp is free.
4607 On NDS32, the following registers are used:
4609 R0-R1: argument/return
4611 R15: temporary register for assembler
4612 R16: trampoline register
4613 R28: frame pointer (FP)
4614 R29: global pointer (GP)
4615 R30: link register (LP)
4616 R31: stack pointer (SP)
4617 PC: program counter (PC)
4619 ==> U-Boot will use R10 to hold a pointer to the global data
4621 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4622 or current versions of GCC may "optimize" the code too much.
4627 U-Boot runs in system state and uses physical addresses, i.e. the
4628 MMU is not used either for address mapping nor for memory protection.
4630 The available memory is mapped to fixed addresses using the memory
4631 controller. In this process, a contiguous block is formed for each
4632 memory type (Flash, SDRAM, SRAM), even when it consists of several
4633 physical memory banks.
4635 U-Boot is installed in the first 128 kB of the first Flash bank (on
4636 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4637 booting and sizing and initializing DRAM, the code relocates itself
4638 to the upper end of DRAM. Immediately below the U-Boot code some
4639 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4640 configuration setting]. Below that, a structure with global Board
4641 Info data is placed, followed by the stack (growing downward).
4643 Additionally, some exception handler code is copied to the low 8 kB
4644 of DRAM (0x00000000 ... 0x00001FFF).
4646 So a typical memory configuration with 16 MB of DRAM could look like
4649 0x0000 0000 Exception Vector code
4652 0x0000 2000 Free for Application Use
4658 0x00FB FF20 Monitor Stack (Growing downward)
4659 0x00FB FFAC Board Info Data and permanent copy of global data
4660 0x00FC 0000 Malloc Arena
4663 0x00FE 0000 RAM Copy of Monitor Code
4664 ... eventually: LCD or video framebuffer
4665 ... eventually: pRAM (Protected RAM - unchanged by reset)
4666 0x00FF FFFF [End of RAM]
4669 System Initialization:
4670 ----------------------
4672 In the reset configuration, U-Boot starts at the reset entry point
4673 (on most PowerPC systems at address 0x00000100). Because of the reset
4674 configuration for CS0# this is a mirror of the onboard Flash memory.
4675 To be able to re-map memory U-Boot then jumps to its link address.
4676 To be able to implement the initialization code in C, a (small!)
4677 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4678 which provide such a feature like MPC8xx or MPC8260), or in a locked
4679 part of the data cache. After that, U-Boot initializes the CPU core,
4680 the caches and the SIU.
4682 Next, all (potentially) available memory banks are mapped using a
4683 preliminary mapping. For example, we put them on 512 MB boundaries
4684 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4685 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4686 programmed for SDRAM access. Using the temporary configuration, a
4687 simple memory test is run that determines the size of the SDRAM
4690 When there is more than one SDRAM bank, and the banks are of
4691 different size, the largest is mapped first. For equal size, the first
4692 bank (CS2#) is mapped first. The first mapping is always for address
4693 0x00000000, with any additional banks following immediately to create
4694 contiguous memory starting from 0.
4696 Then, the monitor installs itself at the upper end of the SDRAM area
4697 and allocates memory for use by malloc() and for the global Board
4698 Info data; also, the exception vector code is copied to the low RAM
4699 pages, and the final stack is set up.
4701 Only after this relocation will you have a "normal" C environment;
4702 until that you are restricted in several ways, mostly because you are
4703 running from ROM, and because the code will have to be relocated to a
4707 U-Boot Porting Guide:
4708 ----------------------
4710 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4714 int main(int argc, char *argv[])
4716 sighandler_t no_more_time;
4718 signal(SIGALRM, no_more_time);
4719 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4721 if (available_money > available_manpower) {
4722 Pay consultant to port U-Boot;
4726 Download latest U-Boot source;
4728 Subscribe to u-boot mailing list;
4731 email("Hi, I am new to U-Boot, how do I get started?");
4734 Read the README file in the top level directory;
4735 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4736 Read applicable doc/*.README;
4737 Read the source, Luke;
4738 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4741 if (available_money > toLocalCurrency ($2500))
4744 Add a lot of aggravation and time;
4746 if (a similar board exists) { /* hopefully... */
4747 cp -a board/<similar> board/<myboard>
4748 cp include/configs/<similar>.h include/configs/<myboard>.h
4750 Create your own board support subdirectory;
4751 Create your own board include/configs/<myboard>.h file;
4753 Edit new board/<myboard> files
4754 Edit new include/configs/<myboard>.h
4759 Add / modify source code;
4763 email("Hi, I am having problems...");
4765 Send patch file to the U-Boot email list;
4766 if (reasonable critiques)
4767 Incorporate improvements from email list code review;
4769 Defend code as written;
4775 void no_more_time (int sig)
4784 All contributions to U-Boot should conform to the Linux kernel
4785 coding style; see the file "Documentation/CodingStyle" and the script
4786 "scripts/Lindent" in your Linux kernel source directory.
4788 Source files originating from a different project (for example the
4789 MTD subsystem) are generally exempt from these guidelines and are not
4790 reformated to ease subsequent migration to newer versions of those
4793 Please note that U-Boot is implemented in C (and to some small parts in
4794 Assembler); no C++ is used, so please do not use C++ style comments (//)
4797 Please also stick to the following formatting rules:
4798 - remove any trailing white space
4799 - use TAB characters for indentation and vertical alignment, not spaces
4800 - make sure NOT to use DOS '\r\n' line feeds
4801 - do not add more than 2 consecutive empty lines to source files
4802 - do not add trailing empty lines to source files
4804 Submissions which do not conform to the standards may be returned
4805 with a request to reformat the changes.
4811 Since the number of patches for U-Boot is growing, we need to
4812 establish some rules. Submissions which do not conform to these rules
4813 may be rejected, even when they contain important and valuable stuff.
4815 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4817 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4818 see http://lists.denx.de/mailman/listinfo/u-boot
4820 When you send a patch, please include the following information with
4823 * For bug fixes: a description of the bug and how your patch fixes
4824 this bug. Please try to include a way of demonstrating that the
4825 patch actually fixes something.
4827 * For new features: a description of the feature and your
4830 * A CHANGELOG entry as plaintext (separate from the patch)
4832 * For major contributions, your entry to the CREDITS file
4834 * When you add support for a new board, don't forget to add this
4835 board to the MAINTAINERS file, too.
4837 * If your patch adds new configuration options, don't forget to
4838 document these in the README file.
4840 * The patch itself. If you are using git (which is *strongly*
4841 recommended) you can easily generate the patch using the
4842 "git format-patch". If you then use "git send-email" to send it to
4843 the U-Boot mailing list, you will avoid most of the common problems
4844 with some other mail clients.
4846 If you cannot use git, use "diff -purN OLD NEW". If your version of
4847 diff does not support these options, then get the latest version of
4850 The current directory when running this command shall be the parent
4851 directory of the U-Boot source tree (i. e. please make sure that
4852 your patch includes sufficient directory information for the
4855 We prefer patches as plain text. MIME attachments are discouraged,
4856 and compressed attachments must not be used.
4858 * If one logical set of modifications affects or creates several
4859 files, all these changes shall be submitted in a SINGLE patch file.
4861 * Changesets that contain different, unrelated modifications shall be
4862 submitted as SEPARATE patches, one patch per changeset.
4867 * Before sending the patch, run the MAKEALL script on your patched
4868 source tree and make sure that no errors or warnings are reported
4869 for any of the boards.
4871 * Keep your modifications to the necessary minimum: A patch
4872 containing several unrelated changes or arbitrary reformats will be
4873 returned with a request to re-formatting / split it.
4875 * If you modify existing code, make sure that your new code does not
4876 add to the memory footprint of the code ;-) Small is beautiful!
4877 When adding new features, these should compile conditionally only
4878 (using #ifdef), and the resulting code with the new feature
4879 disabled must not need more memory than the old code without your
4882 * Remember that there is a size limit of 100 kB per message on the
4883 u-boot mailing list. Bigger patches will be moderated. If they are
4884 reasonable and not too big, they will be acknowledged. But patches
4885 bigger than the size limit should be avoided.
projects / kernel / u-boot.git / blob