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 CONFIG_SYS_PPC_E500_DEBUG_TLB
379 Enables a temporary TLB entry to be used during boot to work
380 around limitations in e500v1 and e500v2 external debugger
381 support. This reduces the portions of the boot code where
382 breakpoints and single stepping do not work. The value of this
383 symbol should be set to the TLB1 entry to be used for this
386 CONFIG_SYS_FSL_ERRATUM_A004510
388 Enables a workaround for erratum A004510. If set,
389 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
390 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
392 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
393 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
395 Defines one or two SoC revisions (low 8 bits of SVR)
396 for which the A004510 workaround should be applied.
398 The rest of SVR is either not relevant to the decision
399 of whether the erratum is present (e.g. p2040 versus
400 p2041) or is implied by the build target, which controls
401 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
403 See Freescale App Note 4493 for more information about
406 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
408 This is the value to write into CCSR offset 0x18600
409 according to the A004510 workaround.
411 - Generic CPU options:
412 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
414 Defines the endianess of the CPU. Implementation of those
415 values is arch specific.
417 - Intel Monahans options:
418 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
420 Defines the Monahans run mode to oscillator
421 ratio. Valid values are 8, 16, 24, 31. The core
422 frequency is this value multiplied by 13 MHz.
424 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
426 Defines the Monahans turbo mode to oscillator
427 ratio. Valid values are 1 (default if undefined) and
428 2. The core frequency as calculated above is multiplied
432 CONFIG_SYS_INIT_SP_OFFSET
434 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
435 pointer. This is needed for the temporary stack before
438 CONFIG_SYS_MIPS_CACHE_MODE
440 Cache operation mode for the MIPS CPU.
441 See also arch/mips/include/asm/mipsregs.h.
443 CONF_CM_CACHABLE_NO_WA
446 CONF_CM_CACHABLE_NONCOHERENT
450 CONF_CM_CACHABLE_ACCELERATED
452 CONFIG_SYS_XWAY_EBU_BOOTCFG
454 Special option for Lantiq XWAY SoCs for booting from NOR flash.
455 See also arch/mips/cpu/mips32/start.S.
457 CONFIG_XWAY_SWAP_BYTES
459 Enable compilation of tools/xway-swap-bytes needed for Lantiq
460 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
461 be swapped if a flash programmer is used.
464 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
466 Select high exception vectors of the ARM core, e.g., do not
467 clear the V bit of the c1 register of CP15.
469 CONFIG_SYS_THUMB_BUILD
471 Use this flag to build U-Boot using the Thumb instruction
472 set for ARM architectures. Thumb instruction set provides
473 better code density. For ARM architectures that support
474 Thumb2 this flag will result in Thumb2 code generated by
477 - Linux Kernel Interface:
480 U-Boot stores all clock information in Hz
481 internally. For binary compatibility with older Linux
482 kernels (which expect the clocks passed in the
483 bd_info data to be in MHz) the environment variable
484 "clocks_in_mhz" can be defined so that U-Boot
485 converts clock data to MHZ before passing it to the
487 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
488 "clocks_in_mhz=1" is automatically included in the
491 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
493 When transferring memsize parameter to linux, some versions
494 expect it to be in bytes, others in MB.
495 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
499 New kernel versions are expecting firmware settings to be
500 passed using flattened device trees (based on open firmware
504 * New libfdt-based support
505 * Adds the "fdt" command
506 * The bootm command automatically updates the fdt
508 OF_CPU - The proper name of the cpus node (only required for
509 MPC512X and MPC5xxx based boards).
510 OF_SOC - The proper name of the soc node (only required for
511 MPC512X and MPC5xxx based boards).
512 OF_TBCLK - The timebase frequency.
513 OF_STDOUT_PATH - The path to the console device
515 boards with QUICC Engines require OF_QE to set UCC MAC
518 CONFIG_OF_BOARD_SETUP
520 Board code has addition modification that it wants to make
521 to the flat device tree before handing it off to the kernel
525 This define fills in the correct boot CPU in the boot
526 param header, the default value is zero if undefined.
530 U-Boot can detect if an IDE device is present or not.
531 If not, and this new config option is activated, U-Boot
532 removes the ATA node from the DTS before booting Linux,
533 so the Linux IDE driver does not probe the device and
534 crash. This is needed for buggy hardware (uc101) where
535 no pull down resistor is connected to the signal IDE5V_DD7.
537 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
539 This setting is mandatory for all boards that have only one
540 machine type and must be used to specify the machine type
541 number as it appears in the ARM machine registry
542 (see http://www.arm.linux.org.uk/developer/machines/).
543 Only boards that have multiple machine types supported
544 in a single configuration file and the machine type is
545 runtime discoverable, do not have to use this setting.
547 - vxWorks boot parameters:
549 bootvx constructs a valid bootline using the following
550 environments variables: bootfile, ipaddr, serverip, hostname.
551 It loads the vxWorks image pointed bootfile.
553 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
554 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
555 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
556 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
558 CONFIG_SYS_VXWORKS_ADD_PARAMS
560 Add it at the end of the bootline. E.g "u=username pw=secret"
562 Note: If a "bootargs" environment is defined, it will overwride
563 the defaults discussed just above.
565 - Cache Configuration:
566 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
567 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
568 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
570 - Cache Configuration for ARM:
571 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
573 CONFIG_SYS_PL310_BASE - Physical base address of PL310
574 controller register space
579 Define this if you want support for Amba PrimeCell PL010 UARTs.
583 Define this if you want support for Amba PrimeCell PL011 UARTs.
587 If you have Amba PrimeCell PL011 UARTs, set this variable to
588 the clock speed of the UARTs.
592 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
593 define this to a list of base addresses for each (supported)
594 port. See e.g. include/configs/versatile.h
596 CONFIG_PL011_SERIAL_RLCR
598 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
599 have separate receive and transmit line control registers. Set
600 this variable to initialize the extra register.
602 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
604 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
605 boot loader that has already initialized the UART. Define this
606 variable to flush the UART at init time.
610 Depending on board, define exactly one serial port
611 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
612 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
613 console by defining CONFIG_8xx_CONS_NONE
615 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
616 port routines must be defined elsewhere
617 (i.e. serial_init(), serial_getc(), ...)
620 Enables console device for a color framebuffer. Needs following
621 defines (cf. smiLynxEM, i8042)
622 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
624 VIDEO_HW_RECTFILL graphic chip supports
627 VIDEO_HW_BITBLT graphic chip supports
628 bit-blit (cf. smiLynxEM)
629 VIDEO_VISIBLE_COLS visible pixel columns
631 VIDEO_VISIBLE_ROWS visible pixel rows
632 VIDEO_PIXEL_SIZE bytes per pixel
633 VIDEO_DATA_FORMAT graphic data format
634 (0-5, cf. cfb_console.c)
635 VIDEO_FB_ADRS framebuffer address
636 VIDEO_KBD_INIT_FCT keyboard int fct
637 (i.e. i8042_kbd_init())
638 VIDEO_TSTC_FCT test char fct
640 VIDEO_GETC_FCT get char fct
642 CONFIG_CONSOLE_CURSOR cursor drawing on/off
643 (requires blink timer
645 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
646 CONFIG_CONSOLE_TIME display time/date info in
648 (requires CONFIG_CMD_DATE)
649 CONFIG_VIDEO_LOGO display Linux logo in
651 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
652 linux_logo.h for logo.
653 Requires CONFIG_VIDEO_LOGO
654 CONFIG_CONSOLE_EXTRA_INFO
655 additional board info beside
658 When CONFIG_CFB_CONSOLE is defined, video console is
659 default i/o. Serial console can be forced with
660 environment 'console=serial'.
662 When CONFIG_SILENT_CONSOLE is defined, all console
663 messages (by U-Boot and Linux!) can be silenced with
664 the "silent" environment variable. See
665 doc/README.silent for more information.
668 CONFIG_BAUDRATE - in bps
669 Select one of the baudrates listed in
670 CONFIG_SYS_BAUDRATE_TABLE, see below.
671 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
673 - Console Rx buffer length
674 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
675 the maximum receive buffer length for the SMC.
676 This option is actual only for 82xx and 8xx possible.
677 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
678 must be defined, to setup the maximum idle timeout for
681 - Pre-Console Buffer:
682 Prior to the console being initialised (i.e. serial UART
683 initialised etc) all console output is silently discarded.
684 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
685 buffer any console messages prior to the console being
686 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
687 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
688 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
689 bytes are output before the console is initialised, the
690 earlier bytes are discarded.
692 'Sane' compilers will generate smaller code if
693 CONFIG_PRE_CON_BUF_SZ is a power of 2
695 - Safe printf() functions
696 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
697 the printf() functions. These are defined in
698 include/vsprintf.h and include snprintf(), vsnprintf() and
699 so on. Code size increase is approximately 300-500 bytes.
700 If this option is not given then these functions will
701 silently discard their buffer size argument - this means
702 you are not getting any overflow checking in this case.
704 - Boot Delay: CONFIG_BOOTDELAY - in seconds
705 Delay before automatically booting the default image;
706 set to -1 to disable autoboot.
707 set to -2 to autoboot with no delay and not check for abort
708 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
710 See doc/README.autoboot for these options that
711 work with CONFIG_BOOTDELAY. None are required.
712 CONFIG_BOOT_RETRY_TIME
713 CONFIG_BOOT_RETRY_MIN
714 CONFIG_AUTOBOOT_KEYED
715 CONFIG_AUTOBOOT_PROMPT
716 CONFIG_AUTOBOOT_DELAY_STR
717 CONFIG_AUTOBOOT_STOP_STR
718 CONFIG_AUTOBOOT_DELAY_STR2
719 CONFIG_AUTOBOOT_STOP_STR2
720 CONFIG_ZERO_BOOTDELAY_CHECK
721 CONFIG_RESET_TO_RETRY
725 Only needed when CONFIG_BOOTDELAY is enabled;
726 define a command string that is automatically executed
727 when no character is read on the console interface
728 within "Boot Delay" after reset.
731 This can be used to pass arguments to the bootm
732 command. The value of CONFIG_BOOTARGS goes into the
733 environment value "bootargs".
735 CONFIG_RAMBOOT and CONFIG_NFSBOOT
736 The value of these goes into the environment as
737 "ramboot" and "nfsboot" respectively, and can be used
738 as a convenience, when switching between booting from
744 When this option is #defined, the existence of the
745 environment variable "preboot" will be checked
746 immediately before starting the CONFIG_BOOTDELAY
747 countdown and/or running the auto-boot command resp.
748 entering interactive mode.
750 This feature is especially useful when "preboot" is
751 automatically generated or modified. For an example
752 see the LWMON board specific code: here "preboot" is
753 modified when the user holds down a certain
754 combination of keys on the (special) keyboard when
757 - Serial Download Echo Mode:
759 If defined to 1, all characters received during a
760 serial download (using the "loads" command) are
761 echoed back. This might be needed by some terminal
762 emulations (like "cu"), but may as well just take
763 time on others. This setting #define's the initial
764 value of the "loads_echo" environment variable.
766 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
768 Select one of the baudrates listed in
769 CONFIG_SYS_BAUDRATE_TABLE, see below.
772 Monitor commands can be included or excluded
773 from the build by using the #include files
774 <config_cmd_all.h> and #undef'ing unwanted
775 commands, or using <config_cmd_default.h>
776 and augmenting with additional #define's
779 The default command configuration includes all commands
780 except those marked below with a "*".
782 CONFIG_CMD_ASKENV * ask for env variable
783 CONFIG_CMD_BDI bdinfo
784 CONFIG_CMD_BEDBUG * Include BedBug Debugger
785 CONFIG_CMD_BMP * BMP support
786 CONFIG_CMD_BSP * Board specific commands
787 CONFIG_CMD_BOOTD bootd
788 CONFIG_CMD_CACHE * icache, dcache
789 CONFIG_CMD_CONSOLE coninfo
790 CONFIG_CMD_CRC32 * crc32
791 CONFIG_CMD_DATE * support for RTC, date/time...
792 CONFIG_CMD_DHCP * DHCP support
793 CONFIG_CMD_DIAG * Diagnostics
794 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
795 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
796 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
797 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
798 CONFIG_CMD_DTT * Digital Therm and Thermostat
799 CONFIG_CMD_ECHO echo arguments
800 CONFIG_CMD_EDITENV edit env variable
801 CONFIG_CMD_EEPROM * EEPROM read/write support
802 CONFIG_CMD_ELF * bootelf, bootvx
803 CONFIG_CMD_EXPORTENV * export the environment
804 CONFIG_CMD_SAVEENV saveenv
805 CONFIG_CMD_FDC * Floppy Disk Support
806 CONFIG_CMD_FAT * FAT partition support
807 CONFIG_CMD_FDOS * Dos diskette Support
808 CONFIG_CMD_FLASH flinfo, erase, protect
809 CONFIG_CMD_FPGA FPGA device initialization support
810 CONFIG_CMD_GO * the 'go' command (exec code)
811 CONFIG_CMD_GREPENV * search environment
812 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
813 CONFIG_CMD_I2C * I2C serial bus support
814 CONFIG_CMD_IDE * IDE harddisk support
815 CONFIG_CMD_IMI iminfo
816 CONFIG_CMD_IMLS List all found images
817 CONFIG_CMD_IMMAP * IMMR dump support
818 CONFIG_CMD_IMPORTENV * import an environment
819 CONFIG_CMD_INI * import data from an ini file into the env
820 CONFIG_CMD_IRQ * irqinfo
821 CONFIG_CMD_ITEST Integer/string test of 2 values
822 CONFIG_CMD_JFFS2 * JFFS2 Support
823 CONFIG_CMD_KGDB * kgdb
824 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
825 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
827 CONFIG_CMD_LOADB loadb
828 CONFIG_CMD_LOADS loads
829 CONFIG_CMD_MD5SUM print md5 message digest
830 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
831 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
833 CONFIG_CMD_MISC Misc functions like sleep etc
834 CONFIG_CMD_MMC * MMC memory mapped support
835 CONFIG_CMD_MII * MII utility commands
836 CONFIG_CMD_MTDPARTS * MTD partition support
837 CONFIG_CMD_NAND * NAND support
838 CONFIG_CMD_NET bootp, tftpboot, rarpboot
839 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
840 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
841 CONFIG_CMD_PCI * pciinfo
842 CONFIG_CMD_PCMCIA * PCMCIA support
843 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
845 CONFIG_CMD_PORTIO * Port I/O
846 CONFIG_CMD_REGINFO * Register dump
847 CONFIG_CMD_RUN run command in env variable
848 CONFIG_CMD_SAVES * save S record dump
849 CONFIG_CMD_SCSI * SCSI Support
850 CONFIG_CMD_SDRAM * print SDRAM configuration information
851 (requires CONFIG_CMD_I2C)
852 CONFIG_CMD_SETGETDCR Support for DCR Register access
854 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
855 CONFIG_CMD_SHA1SUM print sha1 memory digest
856 (requires CONFIG_CMD_MEMORY)
857 CONFIG_CMD_SOURCE "source" command Support
858 CONFIG_CMD_SPI * SPI serial bus support
859 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
860 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
861 CONFIG_CMD_TIME * run command and report execution time
862 CONFIG_CMD_USB * USB support
863 CONFIG_CMD_CDP * Cisco Discover Protocol support
864 CONFIG_CMD_MFSL * Microblaze FSL support
867 EXAMPLE: If you want all functions except of network
868 support you can write:
870 #include "config_cmd_all.h"
871 #undef CONFIG_CMD_NET
874 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
876 Note: Don't enable the "icache" and "dcache" commands
877 (configuration option CONFIG_CMD_CACHE) unless you know
878 what you (and your U-Boot users) are doing. Data
879 cache cannot be enabled on systems like the 8xx or
880 8260 (where accesses to the IMMR region must be
881 uncached), and it cannot be disabled on all other
882 systems where we (mis-) use the data cache to hold an
883 initial stack and some data.
886 XXX - this list needs to get updated!
890 If this variable is defined, U-Boot will use a device tree
891 to configure its devices, instead of relying on statically
892 compiled #defines in the board file. This option is
893 experimental and only available on a few boards. The device
894 tree is available in the global data as gd->fdt_blob.
896 U-Boot needs to get its device tree from somewhere. This can
897 be done using one of the two options below:
900 If this variable is defined, U-Boot will embed a device tree
901 binary in its image. This device tree file should be in the
902 board directory and called <soc>-<board>.dts. The binary file
903 is then picked up in board_init_f() and made available through
904 the global data structure as gd->blob.
907 If this variable is defined, U-Boot will build a device tree
908 binary. It will be called u-boot.dtb. Architecture-specific
909 code will locate it at run-time. Generally this works by:
911 cat u-boot.bin u-boot.dtb >image.bin
913 and in fact, U-Boot does this for you, creating a file called
914 u-boot-dtb.bin which is useful in the common case. You can
915 still use the individual files if you need something more
920 If this variable is defined, it enables watchdog
921 support for the SoC. There must be support in the SoC
922 specific code for a watchdog. For the 8xx and 8260
923 CPUs, the SIU Watchdog feature is enabled in the SYPCR
924 register. When supported for a specific SoC is
925 available, then no further board specific code should
929 When using a watchdog circuitry external to the used
930 SoC, then define this variable and provide board
931 specific code for the "hw_watchdog_reset" function.
934 CONFIG_VERSION_VARIABLE
935 If this variable is defined, an environment variable
936 named "ver" is created by U-Boot showing the U-Boot
937 version as printed by the "version" command.
938 Any change to this variable will be reverted at the
943 When CONFIG_CMD_DATE is selected, the type of the RTC
944 has to be selected, too. Define exactly one of the
947 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
948 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
949 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
950 CONFIG_RTC_MC146818 - use MC146818 RTC
951 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
952 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
953 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
954 CONFIG_RTC_DS164x - use Dallas DS164x RTC
955 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
956 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
957 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
958 CONFIG_SYS_RV3029_TCR - enable trickle charger on
961 Note that if the RTC uses I2C, then the I2C interface
962 must also be configured. See I2C Support, below.
965 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
966 CONFIG_PCA953X_INFO - enable pca953x info command
968 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
969 chip-ngpio pairs that tell the PCA953X driver the number of
970 pins supported by a particular chip.
972 Note that if the GPIO device uses I2C, then the I2C interface
973 must also be configured. See I2C Support, below.
977 When CONFIG_TIMESTAMP is selected, the timestamp
978 (date and time) of an image is printed by image
979 commands like bootm or iminfo. This option is
980 automatically enabled when you select CONFIG_CMD_DATE .
982 - Partition Labels (disklabels) Supported:
983 Zero or more of the following:
984 CONFIG_MAC_PARTITION Apple's MacOS partition table.
985 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
986 Intel architecture, USB sticks, etc.
987 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
988 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
989 bootloader. Note 2TB partition limit; see
991 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
993 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
994 CONFIG_CMD_SCSI) you must configure support for at
995 least one non-MTD partition type as well.
998 CONFIG_IDE_RESET_ROUTINE - this is defined in several
999 board configurations files but used nowhere!
1001 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1002 be performed by calling the function
1003 ide_set_reset(int reset)
1004 which has to be defined in a board specific file
1009 Set this to enable ATAPI support.
1014 Set this to enable support for disks larger than 137GB
1015 Also look at CONFIG_SYS_64BIT_LBA.
1016 Whithout these , LBA48 support uses 32bit variables and will 'only'
1017 support disks up to 2.1TB.
1019 CONFIG_SYS_64BIT_LBA:
1020 When enabled, makes the IDE subsystem use 64bit sector addresses.
1024 At the moment only there is only support for the
1025 SYM53C8XX SCSI controller; define
1026 CONFIG_SCSI_SYM53C8XX to enable it.
1028 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1029 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1030 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1031 maximum numbers of LUNs, SCSI ID's and target
1033 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1035 - NETWORK Support (PCI):
1037 Support for Intel 8254x/8257x gigabit chips.
1040 Utility code for direct access to the SPI bus on Intel 8257x.
1041 This does not do anything useful unless you set at least one
1042 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1044 CONFIG_E1000_SPI_GENERIC
1045 Allow generic access to the SPI bus on the Intel 8257x, for
1046 example with the "sspi" command.
1049 Management command for E1000 devices. When used on devices
1050 with SPI support you can reprogram the EEPROM from U-Boot.
1052 CONFIG_E1000_FALLBACK_MAC
1053 default MAC for empty EEPROM after production.
1056 Support for Intel 82557/82559/82559ER chips.
1057 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1058 write routine for first time initialisation.
1061 Support for Digital 2114x chips.
1062 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1063 modem chip initialisation (KS8761/QS6611).
1066 Support for National dp83815 chips.
1069 Support for National dp8382[01] gigabit chips.
1071 - NETWORK Support (other):
1073 CONFIG_DRIVER_AT91EMAC
1074 Support for AT91RM9200 EMAC.
1077 Define this to use reduced MII inteface
1079 CONFIG_DRIVER_AT91EMAC_QUIET
1080 If this defined, the driver is quiet.
1081 The driver doen't show link status messages.
1083 CONFIG_CALXEDA_XGMAC
1084 Support for the Calxeda XGMAC device
1086 CONFIG_DRIVER_LAN91C96
1087 Support for SMSC's LAN91C96 chips.
1089 CONFIG_LAN91C96_BASE
1090 Define this to hold the physical address
1091 of the LAN91C96's I/O space
1093 CONFIG_LAN91C96_USE_32_BIT
1094 Define this to enable 32 bit addressing
1096 CONFIG_DRIVER_SMC91111
1097 Support for SMSC's LAN91C111 chip
1099 CONFIG_SMC91111_BASE
1100 Define this to hold the physical address
1101 of the device (I/O space)
1103 CONFIG_SMC_USE_32_BIT
1104 Define this if data bus is 32 bits
1106 CONFIG_SMC_USE_IOFUNCS
1107 Define this to use i/o functions instead of macros
1108 (some hardware wont work with macros)
1110 CONFIG_DRIVER_TI_EMAC
1111 Support for davinci emac
1113 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1114 Define this if you have more then 3 PHYs.
1117 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1119 CONFIG_FTGMAC100_EGIGA
1120 Define this to use GE link update with gigabit PHY.
1121 Define this if FTGMAC100 is connected to gigabit PHY.
1122 If your system has 10/100 PHY only, it might not occur
1123 wrong behavior. Because PHY usually return timeout or
1124 useless data when polling gigabit status and gigabit
1125 control registers. This behavior won't affect the
1126 correctnessof 10/100 link speed update.
1129 Support for SMSC's LAN911x and LAN921x chips
1132 Define this to hold the physical address
1133 of the device (I/O space)
1135 CONFIG_SMC911X_32_BIT
1136 Define this if data bus is 32 bits
1138 CONFIG_SMC911X_16_BIT
1139 Define this if data bus is 16 bits. If your processor
1140 automatically converts one 32 bit word to two 16 bit
1141 words you may also try CONFIG_SMC911X_32_BIT.
1144 Support for Renesas on-chip Ethernet controller
1146 CONFIG_SH_ETHER_USE_PORT
1147 Define the number of ports to be used
1149 CONFIG_SH_ETHER_PHY_ADDR
1150 Define the ETH PHY's address
1152 CONFIG_SH_ETHER_CACHE_WRITEBACK
1153 If this option is set, the driver enables cache flush.
1156 CONFIG_GENERIC_LPC_TPM
1157 Support for generic parallel port TPM devices. Only one device
1158 per system is supported at this time.
1160 CONFIG_TPM_TIS_BASE_ADDRESS
1161 Base address where the generic TPM device is mapped
1162 to. Contemporary x86 systems usually map it at
1166 At the moment only the UHCI host controller is
1167 supported (PIP405, MIP405, MPC5200); define
1168 CONFIG_USB_UHCI to enable it.
1169 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1170 and define CONFIG_USB_STORAGE to enable the USB
1173 Supported are USB Keyboards and USB Floppy drives
1175 MPC5200 USB requires additional defines:
1177 for 528 MHz Clock: 0x0001bbbb
1181 for differential drivers: 0x00001000
1182 for single ended drivers: 0x00005000
1183 for differential drivers on PSC3: 0x00000100
1184 for single ended drivers on PSC3: 0x00004100
1185 CONFIG_SYS_USB_EVENT_POLL
1186 May be defined to allow interrupt polling
1187 instead of using asynchronous interrupts
1189 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1190 txfilltuning field in the EHCI controller on reset.
1193 Define the below if you wish to use the USB console.
1194 Once firmware is rebuilt from a serial console issue the
1195 command "setenv stdin usbtty; setenv stdout usbtty" and
1196 attach your USB cable. The Unix command "dmesg" should print
1197 it has found a new device. The environment variable usbtty
1198 can be set to gserial or cdc_acm to enable your device to
1199 appear to a USB host as a Linux gserial device or a
1200 Common Device Class Abstract Control Model serial device.
1201 If you select usbtty = gserial you should be able to enumerate
1203 # modprobe usbserial vendor=0xVendorID product=0xProductID
1204 else if using cdc_acm, simply setting the environment
1205 variable usbtty to be cdc_acm should suffice. The following
1206 might be defined in YourBoardName.h
1209 Define this to build a UDC device
1212 Define this to have a tty type of device available to
1213 talk to the UDC device
1216 Define this to enable the high speed support for usb
1217 device and usbtty. If this feature is enabled, a routine
1218 int is_usbd_high_speed(void)
1219 also needs to be defined by the driver to dynamically poll
1220 whether the enumeration has succeded at high speed or full
1223 CONFIG_SYS_CONSOLE_IS_IN_ENV
1224 Define this if you want stdin, stdout &/or stderr to
1228 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1229 Derive USB clock from external clock "blah"
1230 - CONFIG_SYS_USB_EXTC_CLK 0x02
1232 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1233 Derive USB clock from brgclk
1234 - CONFIG_SYS_USB_BRG_CLK 0x04
1236 If you have a USB-IF assigned VendorID then you may wish to
1237 define your own vendor specific values either in BoardName.h
1238 or directly in usbd_vendor_info.h. If you don't define
1239 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1240 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1241 should pretend to be a Linux device to it's target host.
1243 CONFIG_USBD_MANUFACTURER
1244 Define this string as the name of your company for
1245 - CONFIG_USBD_MANUFACTURER "my company"
1247 CONFIG_USBD_PRODUCT_NAME
1248 Define this string as the name of your product
1249 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1251 CONFIG_USBD_VENDORID
1252 Define this as your assigned Vendor ID from the USB
1253 Implementors Forum. This *must* be a genuine Vendor ID
1254 to avoid polluting the USB namespace.
1255 - CONFIG_USBD_VENDORID 0xFFFF
1257 CONFIG_USBD_PRODUCTID
1258 Define this as the unique Product ID
1260 - CONFIG_USBD_PRODUCTID 0xFFFF
1262 - ULPI Layer Support:
1263 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1264 the generic ULPI layer. The generic layer accesses the ULPI PHY
1265 via the platform viewport, so you need both the genric layer and
1266 the viewport enabled. Currently only Chipidea/ARC based
1267 viewport is supported.
1268 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1269 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1272 The MMC controller on the Intel PXA is supported. To
1273 enable this define CONFIG_MMC. The MMC can be
1274 accessed from the boot prompt by mapping the device
1275 to physical memory similar to flash. Command line is
1276 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1277 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1280 Support for Renesas on-chip MMCIF controller
1282 CONFIG_SH_MMCIF_ADDR
1283 Define the base address of MMCIF registers
1286 Define the clock frequency for MMCIF
1288 - Journaling Flash filesystem support:
1289 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1290 CONFIG_JFFS2_NAND_DEV
1291 Define these for a default partition on a NAND device
1293 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1294 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1295 Define these for a default partition on a NOR device
1297 CONFIG_SYS_JFFS_CUSTOM_PART
1298 Define this to create an own partition. You have to provide a
1299 function struct part_info* jffs2_part_info(int part_num)
1301 If you define only one JFFS2 partition you may also want to
1302 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1303 to disable the command chpart. This is the default when you
1304 have not defined a custom partition
1306 - FAT(File Allocation Table) filesystem write function support:
1309 Define this to enable support for saving memory data as a
1310 file in FAT formatted partition.
1312 This will also enable the command "fatwrite" enabling the
1313 user to write files to FAT.
1318 Define this to enable standard (PC-Style) keyboard
1322 Standard PC keyboard driver with US (is default) and
1323 GERMAN key layout (switch via environment 'keymap=de') support.
1324 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1325 for cfb_console. Supports cursor blinking.
1330 Define this to enable video support (for output to
1333 CONFIG_VIDEO_CT69000
1335 Enable Chips & Technologies 69000 Video chip
1337 CONFIG_VIDEO_SMI_LYNXEM
1338 Enable Silicon Motion SMI 712/710/810 Video chip. The
1339 video output is selected via environment 'videoout'
1340 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1343 For the CT69000 and SMI_LYNXEM drivers, videomode is
1344 selected via environment 'videomode'. Two different ways
1346 - "videomode=num" 'num' is a standard LiLo mode numbers.
1347 Following standard modes are supported (* is default):
1349 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1350 -------------+---------------------------------------------
1351 8 bits | 0x301* 0x303 0x305 0x161 0x307
1352 15 bits | 0x310 0x313 0x316 0x162 0x319
1353 16 bits | 0x311 0x314 0x317 0x163 0x31A
1354 24 bits | 0x312 0x315 0x318 ? 0x31B
1355 -------------+---------------------------------------------
1356 (i.e. setenv videomode 317; saveenv; reset;)
1358 - "videomode=bootargs" all the video parameters are parsed
1359 from the bootargs. (See drivers/video/videomodes.c)
1362 CONFIG_VIDEO_SED13806
1363 Enable Epson SED13806 driver. This driver supports 8bpp
1364 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1365 or CONFIG_VIDEO_SED13806_16BPP
1368 Enable the Freescale DIU video driver. Reference boards for
1369 SOCs that have a DIU should define this macro to enable DIU
1370 support, and should also define these other macros:
1376 CONFIG_VIDEO_SW_CURSOR
1377 CONFIG_VGA_AS_SINGLE_DEVICE
1379 CONFIG_VIDEO_BMP_LOGO
1381 The DIU driver will look for the 'video-mode' environment
1382 variable, and if defined, enable the DIU as a console during
1383 boot. See the documentation file README.video for a
1384 description of this variable.
1389 Define this to enable a custom keyboard support.
1390 This simply calls drv_keyboard_init() which must be
1391 defined in your board-specific files.
1392 The only board using this so far is RBC823.
1394 - LCD Support: CONFIG_LCD
1396 Define this to enable LCD support (for output to LCD
1397 display); also select one of the supported displays
1398 by defining one of these:
1402 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1404 CONFIG_NEC_NL6448AC33:
1406 NEC NL6448AC33-18. Active, color, single scan.
1408 CONFIG_NEC_NL6448BC20
1410 NEC NL6448BC20-08. 6.5", 640x480.
1411 Active, color, single scan.
1413 CONFIG_NEC_NL6448BC33_54
1415 NEC NL6448BC33-54. 10.4", 640x480.
1416 Active, color, single scan.
1420 Sharp 320x240. Active, color, single scan.
1421 It isn't 16x9, and I am not sure what it is.
1423 CONFIG_SHARP_LQ64D341
1425 Sharp LQ64D341 display, 640x480.
1426 Active, color, single scan.
1430 HLD1045 display, 640x480.
1431 Active, color, single scan.
1435 Optrex CBL50840-2 NF-FW 99 22 M5
1437 Hitachi LMG6912RPFC-00T
1441 320x240. Black & white.
1443 Normally display is black on white background; define
1444 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1446 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1448 If this option is set, the environment is checked for
1449 a variable "splashimage". If found, the usual display
1450 of logo, copyright and system information on the LCD
1451 is suppressed and the BMP image at the address
1452 specified in "splashimage" is loaded instead. The
1453 console is redirected to the "nulldev", too. This
1454 allows for a "silent" boot where a splash screen is
1455 loaded very quickly after power-on.
1457 CONFIG_SPLASH_SCREEN_ALIGN
1459 If this option is set the splash image can be freely positioned
1460 on the screen. Environment variable "splashpos" specifies the
1461 position as "x,y". If a positive number is given it is used as
1462 number of pixel from left/top. If a negative number is given it
1463 is used as number of pixel from right/bottom. You can also
1464 specify 'm' for centering the image.
1467 setenv splashpos m,m
1468 => image at center of screen
1470 setenv splashpos 30,20
1471 => image at x = 30 and y = 20
1473 setenv splashpos -10,m
1474 => vertically centered image
1475 at x = dspWidth - bmpWidth - 9
1477 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1479 If this option is set, additionally to standard BMP
1480 images, gzipped BMP images can be displayed via the
1481 splashscreen support or the bmp command.
1483 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1485 If this option is set, 8-bit RLE compressed BMP images
1486 can be displayed via the splashscreen support or the
1489 - Do compresssing for memory range:
1492 If this option is set, it would use zlib deflate method
1493 to compress the specified memory at its best effort.
1495 - Compression support:
1498 If this option is set, support for bzip2 compressed
1499 images is included. If not, only uncompressed and gzip
1500 compressed images are supported.
1502 NOTE: the bzip2 algorithm requires a lot of RAM, so
1503 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1508 If this option is set, support for lzma compressed
1511 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1512 requires an amount of dynamic memory that is given by the
1515 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1517 Where lc and lp stand for, respectively, Literal context bits
1518 and Literal pos bits.
1520 This value is upper-bounded by 14MB in the worst case. Anyway,
1521 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1522 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1523 a very small buffer.
1525 Use the lzmainfo tool to determinate the lc and lp values and
1526 then calculate the amount of needed dynamic memory (ensuring
1527 the appropriate CONFIG_SYS_MALLOC_LEN value).
1532 The address of PHY on MII bus.
1534 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1536 The clock frequency of the MII bus
1540 If this option is set, support for speed/duplex
1541 detection of gigabit PHY is included.
1543 CONFIG_PHY_RESET_DELAY
1545 Some PHY like Intel LXT971A need extra delay after
1546 reset before any MII register access is possible.
1547 For such PHY, set this option to the usec delay
1548 required. (minimum 300usec for LXT971A)
1550 CONFIG_PHY_CMD_DELAY (ppc4xx)
1552 Some PHY like Intel LXT971A need extra delay after
1553 command issued before MII status register can be read
1563 Define a default value for Ethernet address to use
1564 for the respective Ethernet interface, in case this
1565 is not determined automatically.
1570 Define a default value for the IP address to use for
1571 the default Ethernet interface, in case this is not
1572 determined through e.g. bootp.
1573 (Environment variable "ipaddr")
1575 - Server IP address:
1578 Defines a default value for the IP address of a TFTP
1579 server to contact when using the "tftboot" command.
1580 (Environment variable "serverip")
1582 CONFIG_KEEP_SERVERADDR
1584 Keeps the server's MAC address, in the env 'serveraddr'
1585 for passing to bootargs (like Linux's netconsole option)
1587 - Gateway IP address:
1590 Defines a default value for the IP address of the
1591 default router where packets to other networks are
1593 (Environment variable "gatewayip")
1598 Defines a default value for the subnet mask (or
1599 routing prefix) which is used to determine if an IP
1600 address belongs to the local subnet or needs to be
1601 forwarded through a router.
1602 (Environment variable "netmask")
1604 - Multicast TFTP Mode:
1607 Defines whether you want to support multicast TFTP as per
1608 rfc-2090; for example to work with atftp. Lets lots of targets
1609 tftp down the same boot image concurrently. Note: the Ethernet
1610 driver in use must provide a function: mcast() to join/leave a
1613 - BOOTP Recovery Mode:
1614 CONFIG_BOOTP_RANDOM_DELAY
1616 If you have many targets in a network that try to
1617 boot using BOOTP, you may want to avoid that all
1618 systems send out BOOTP requests at precisely the same
1619 moment (which would happen for instance at recovery
1620 from a power failure, when all systems will try to
1621 boot, thus flooding the BOOTP server. Defining
1622 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1623 inserted before sending out BOOTP requests. The
1624 following delays are inserted then:
1626 1st BOOTP request: delay 0 ... 1 sec
1627 2nd BOOTP request: delay 0 ... 2 sec
1628 3rd BOOTP request: delay 0 ... 4 sec
1630 BOOTP requests: delay 0 ... 8 sec
1632 - DHCP Advanced Options:
1633 You can fine tune the DHCP functionality by defining
1634 CONFIG_BOOTP_* symbols:
1636 CONFIG_BOOTP_SUBNETMASK
1637 CONFIG_BOOTP_GATEWAY
1638 CONFIG_BOOTP_HOSTNAME
1639 CONFIG_BOOTP_NISDOMAIN
1640 CONFIG_BOOTP_BOOTPATH
1641 CONFIG_BOOTP_BOOTFILESIZE
1644 CONFIG_BOOTP_SEND_HOSTNAME
1645 CONFIG_BOOTP_NTPSERVER
1646 CONFIG_BOOTP_TIMEOFFSET
1647 CONFIG_BOOTP_VENDOREX
1648 CONFIG_BOOTP_MAY_FAIL
1650 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1651 environment variable, not the BOOTP server.
1653 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1654 after the configured retry count, the call will fail
1655 instead of starting over. This can be used to fail over
1656 to Link-local IP address configuration if the DHCP server
1659 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1660 serverip from a DHCP server, it is possible that more
1661 than one DNS serverip is offered to the client.
1662 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1663 serverip will be stored in the additional environment
1664 variable "dnsip2". The first DNS serverip is always
1665 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1668 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1669 to do a dynamic update of a DNS server. To do this, they
1670 need the hostname of the DHCP requester.
1671 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1672 of the "hostname" environment variable is passed as
1673 option 12 to the DHCP server.
1675 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1677 A 32bit value in microseconds for a delay between
1678 receiving a "DHCP Offer" and sending the "DHCP Request".
1679 This fixes a problem with certain DHCP servers that don't
1680 respond 100% of the time to a "DHCP request". E.g. On an
1681 AT91RM9200 processor running at 180MHz, this delay needed
1682 to be *at least* 15,000 usec before a Windows Server 2003
1683 DHCP server would reply 100% of the time. I recommend at
1684 least 50,000 usec to be safe. The alternative is to hope
1685 that one of the retries will be successful but note that
1686 the DHCP timeout and retry process takes a longer than
1689 - Link-local IP address negotiation:
1690 Negotiate with other link-local clients on the local network
1691 for an address that doesn't require explicit configuration.
1692 This is especially useful if a DHCP server cannot be guaranteed
1693 to exist in all environments that the device must operate.
1695 See doc/README.link-local for more information.
1698 CONFIG_CDP_DEVICE_ID
1700 The device id used in CDP trigger frames.
1702 CONFIG_CDP_DEVICE_ID_PREFIX
1704 A two character string which is prefixed to the MAC address
1709 A printf format string which contains the ascii name of
1710 the port. Normally is set to "eth%d" which sets
1711 eth0 for the first Ethernet, eth1 for the second etc.
1713 CONFIG_CDP_CAPABILITIES
1715 A 32bit integer which indicates the device capabilities;
1716 0x00000010 for a normal host which does not forwards.
1720 An ascii string containing the version of the software.
1724 An ascii string containing the name of the platform.
1728 A 32bit integer sent on the trigger.
1730 CONFIG_CDP_POWER_CONSUMPTION
1732 A 16bit integer containing the power consumption of the
1733 device in .1 of milliwatts.
1735 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1737 A byte containing the id of the VLAN.
1739 - Status LED: CONFIG_STATUS_LED
1741 Several configurations allow to display the current
1742 status using a LED. For instance, the LED will blink
1743 fast while running U-Boot code, stop blinking as
1744 soon as a reply to a BOOTP request was received, and
1745 start blinking slow once the Linux kernel is running
1746 (supported by a status LED driver in the Linux
1747 kernel). Defining CONFIG_STATUS_LED enables this
1750 - CAN Support: CONFIG_CAN_DRIVER
1752 Defining CONFIG_CAN_DRIVER enables CAN driver support
1753 on those systems that support this (optional)
1754 feature, like the TQM8xxL modules.
1756 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1758 These enable I2C serial bus commands. Defining either of
1759 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1760 include the appropriate I2C driver for the selected CPU.
1762 This will allow you to use i2c commands at the u-boot
1763 command line (as long as you set CONFIG_CMD_I2C in
1764 CONFIG_COMMANDS) and communicate with i2c based realtime
1765 clock chips. See common/cmd_i2c.c for a description of the
1766 command line interface.
1768 CONFIG_HARD_I2C selects a hardware I2C controller.
1770 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1771 bit-banging) driver instead of CPM or similar hardware
1774 There are several other quantities that must also be
1775 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1777 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1778 to be the frequency (in Hz) at which you wish your i2c bus
1779 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1780 the CPU's i2c node address).
1782 Now, the u-boot i2c code for the mpc8xx
1783 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1784 and so its address should therefore be cleared to 0 (See,
1785 eg, MPC823e User's Manual p.16-473). So, set
1786 CONFIG_SYS_I2C_SLAVE to 0.
1788 CONFIG_SYS_I2C_INIT_MPC5XXX
1790 When a board is reset during an i2c bus transfer
1791 chips might think that the current transfer is still
1792 in progress. Reset the slave devices by sending start
1793 commands until the slave device responds.
1795 That's all that's required for CONFIG_HARD_I2C.
1797 If you use the software i2c interface (CONFIG_SOFT_I2C)
1798 then the following macros need to be defined (examples are
1799 from include/configs/lwmon.h):
1803 (Optional). Any commands necessary to enable the I2C
1804 controller or configure ports.
1806 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1810 (Only for MPC8260 CPU). The I/O port to use (the code
1811 assumes both bits are on the same port). Valid values
1812 are 0..3 for ports A..D.
1816 The code necessary to make the I2C data line active
1817 (driven). If the data line is open collector, this
1820 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1824 The code necessary to make the I2C data line tri-stated
1825 (inactive). If the data line is open collector, this
1828 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1832 Code that returns TRUE if the I2C data line is high,
1835 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1839 If <bit> is TRUE, sets the I2C data line high. If it
1840 is FALSE, it clears it (low).
1842 eg: #define I2C_SDA(bit) \
1843 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1844 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1848 If <bit> is TRUE, sets the I2C clock line high. If it
1849 is FALSE, it clears it (low).
1851 eg: #define I2C_SCL(bit) \
1852 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1853 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1857 This delay is invoked four times per clock cycle so this
1858 controls the rate of data transfer. The data rate thus
1859 is 1 / (I2C_DELAY * 4). Often defined to be something
1862 #define I2C_DELAY udelay(2)
1864 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1866 If your arch supports the generic GPIO framework (asm/gpio.h),
1867 then you may alternatively define the two GPIOs that are to be
1868 used as SCL / SDA. Any of the previous I2C_xxx macros will
1869 have GPIO-based defaults assigned to them as appropriate.
1871 You should define these to the GPIO value as given directly to
1872 the generic GPIO functions.
1874 CONFIG_SYS_I2C_INIT_BOARD
1876 When a board is reset during an i2c bus transfer
1877 chips might think that the current transfer is still
1878 in progress. On some boards it is possible to access
1879 the i2c SCLK line directly, either by using the
1880 processor pin as a GPIO or by having a second pin
1881 connected to the bus. If this option is defined a
1882 custom i2c_init_board() routine in boards/xxx/board.c
1883 is run early in the boot sequence.
1885 CONFIG_SYS_I2C_BOARD_LATE_INIT
1887 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1888 defined a custom i2c_board_late_init() routine in
1889 boards/xxx/board.c is run AFTER the operations in i2c_init()
1890 is completed. This callpoint can be used to unreset i2c bus
1891 using CPU i2c controller register accesses for CPUs whose i2c
1892 controller provide such a method. It is called at the end of
1893 i2c_init() to allow i2c_init operations to setup the i2c bus
1894 controller on the CPU (e.g. setting bus speed & slave address).
1896 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1898 This option enables configuration of bi_iic_fast[] flags
1899 in u-boot bd_info structure based on u-boot environment
1900 variable "i2cfast". (see also i2cfast)
1902 CONFIG_I2C_MULTI_BUS
1904 This option allows the use of multiple I2C buses, each of which
1905 must have a controller. At any point in time, only one bus is
1906 active. To switch to a different bus, use the 'i2c dev' command.
1907 Note that bus numbering is zero-based.
1909 CONFIG_SYS_I2C_NOPROBES
1911 This option specifies a list of I2C devices that will be skipped
1912 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1913 is set, specify a list of bus-device pairs. Otherwise, specify
1914 a 1D array of device addresses
1917 #undef CONFIG_I2C_MULTI_BUS
1918 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1920 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1922 #define CONFIG_I2C_MULTI_BUS
1923 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1925 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1927 CONFIG_SYS_SPD_BUS_NUM
1929 If defined, then this indicates the I2C bus number for DDR SPD.
1930 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1932 CONFIG_SYS_RTC_BUS_NUM
1934 If defined, then this indicates the I2C bus number for the RTC.
1935 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1937 CONFIG_SYS_DTT_BUS_NUM
1939 If defined, then this indicates the I2C bus number for the DTT.
1940 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1942 CONFIG_SYS_I2C_DTT_ADDR:
1944 If defined, specifies the I2C address of the DTT device.
1945 If not defined, then U-Boot uses predefined value for
1946 specified DTT device.
1950 Define this option if you want to use Freescale's I2C driver in
1951 drivers/i2c/fsl_i2c.c.
1955 Define this option if you have I2C devices reached over 1 .. n
1956 I2C Muxes like the pca9544a. This option addes a new I2C
1957 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1958 new I2C Bus to the existing I2C Busses. If you select the
1959 new Bus with "i2c dev", u-bbot sends first the commandos for
1960 the muxes to activate this new "bus".
1962 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1966 Adding a new I2C Bus reached over 2 pca9544a muxes
1967 The First mux with address 70 and channel 6
1968 The Second mux with address 71 and channel 4
1970 => i2c bus pca9544a:70:6:pca9544a:71:4
1972 Use the "i2c bus" command without parameter, to get a list
1973 of I2C Busses with muxes:
1976 Busses reached over muxes:
1978 reached over Mux(es):
1981 reached over Mux(es):
1986 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1987 u-boot first sends the command to the mux@70 to enable
1988 channel 6, and then the command to the mux@71 to enable
1991 After that, you can use the "normal" i2c commands as
1992 usual to communicate with your I2C devices behind
1995 This option is actually implemented for the bitbanging
1996 algorithm in common/soft_i2c.c and for the Hardware I2C
1997 Bus on the MPC8260. But it should be not so difficult
1998 to add this option to other architectures.
2000 CONFIG_SOFT_I2C_READ_REPEATED_START
2002 defining this will force the i2c_read() function in
2003 the soft_i2c driver to perform an I2C repeated start
2004 between writing the address pointer and reading the
2005 data. If this define is omitted the default behaviour
2006 of doing a stop-start sequence will be used. Most I2C
2007 devices can use either method, but some require one or
2010 - SPI Support: CONFIG_SPI
2012 Enables SPI driver (so far only tested with
2013 SPI EEPROM, also an instance works with Crystal A/D and
2014 D/As on the SACSng board)
2018 Enables the driver for SPI controller on SuperH. Currently
2019 only SH7757 is supported.
2023 Enables extended (16-bit) SPI EEPROM addressing.
2024 (symmetrical to CONFIG_I2C_X)
2028 Enables a software (bit-bang) SPI driver rather than
2029 using hardware support. This is a general purpose
2030 driver that only requires three general I/O port pins
2031 (two outputs, one input) to function. If this is
2032 defined, the board configuration must define several
2033 SPI configuration items (port pins to use, etc). For
2034 an example, see include/configs/sacsng.h.
2038 Enables a hardware SPI driver for general-purpose reads
2039 and writes. As with CONFIG_SOFT_SPI, the board configuration
2040 must define a list of chip-select function pointers.
2041 Currently supported on some MPC8xxx processors. For an
2042 example, see include/configs/mpc8349emds.h.
2046 Enables the driver for the SPI controllers on i.MX and MXC
2047 SoCs. Currently i.MX31/35/51 are supported.
2049 - FPGA Support: CONFIG_FPGA
2051 Enables FPGA subsystem.
2053 CONFIG_FPGA_<vendor>
2055 Enables support for specific chip vendors.
2058 CONFIG_FPGA_<family>
2060 Enables support for FPGA family.
2061 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2065 Specify the number of FPGA devices to support.
2067 CONFIG_SYS_FPGA_PROG_FEEDBACK
2069 Enable printing of hash marks during FPGA configuration.
2071 CONFIG_SYS_FPGA_CHECK_BUSY
2073 Enable checks on FPGA configuration interface busy
2074 status by the configuration function. This option
2075 will require a board or device specific function to
2080 If defined, a function that provides delays in the FPGA
2081 configuration driver.
2083 CONFIG_SYS_FPGA_CHECK_CTRLC
2084 Allow Control-C to interrupt FPGA configuration
2086 CONFIG_SYS_FPGA_CHECK_ERROR
2088 Check for configuration errors during FPGA bitfile
2089 loading. For example, abort during Virtex II
2090 configuration if the INIT_B line goes low (which
2091 indicated a CRC error).
2093 CONFIG_SYS_FPGA_WAIT_INIT
2095 Maximum time to wait for the INIT_B line to deassert
2096 after PROB_B has been deasserted during a Virtex II
2097 FPGA configuration sequence. The default time is 500
2100 CONFIG_SYS_FPGA_WAIT_BUSY
2102 Maximum time to wait for BUSY to deassert during
2103 Virtex II FPGA configuration. The default is 5 ms.
2105 CONFIG_SYS_FPGA_WAIT_CONFIG
2107 Time to wait after FPGA configuration. The default is
2110 - Configuration Management:
2113 If defined, this string will be added to the U-Boot
2114 version information (U_BOOT_VERSION)
2116 - Vendor Parameter Protection:
2118 U-Boot considers the values of the environment
2119 variables "serial#" (Board Serial Number) and
2120 "ethaddr" (Ethernet Address) to be parameters that
2121 are set once by the board vendor / manufacturer, and
2122 protects these variables from casual modification by
2123 the user. Once set, these variables are read-only,
2124 and write or delete attempts are rejected. You can
2125 change this behaviour:
2127 If CONFIG_ENV_OVERWRITE is #defined in your config
2128 file, the write protection for vendor parameters is
2129 completely disabled. Anybody can change or delete
2132 Alternatively, if you #define _both_ CONFIG_ETHADDR
2133 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2134 Ethernet address is installed in the environment,
2135 which can be changed exactly ONCE by the user. [The
2136 serial# is unaffected by this, i. e. it remains
2142 Define this variable to enable the reservation of
2143 "protected RAM", i. e. RAM which is not overwritten
2144 by U-Boot. Define CONFIG_PRAM to hold the number of
2145 kB you want to reserve for pRAM. You can overwrite
2146 this default value by defining an environment
2147 variable "pram" to the number of kB you want to
2148 reserve. Note that the board info structure will
2149 still show the full amount of RAM. If pRAM is
2150 reserved, a new environment variable "mem" will
2151 automatically be defined to hold the amount of
2152 remaining RAM in a form that can be passed as boot
2153 argument to Linux, for instance like that:
2155 setenv bootargs ... mem=\${mem}
2158 This way you can tell Linux not to use this memory,
2159 either, which results in a memory region that will
2160 not be affected by reboots.
2162 *WARNING* If your board configuration uses automatic
2163 detection of the RAM size, you must make sure that
2164 this memory test is non-destructive. So far, the
2165 following board configurations are known to be
2168 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2169 HERMES, IP860, RPXlite, LWMON, LANTEC,
2175 Define this variable to stop the system in case of a
2176 fatal error, so that you have to reset it manually.
2177 This is probably NOT a good idea for an embedded
2178 system where you want the system to reboot
2179 automatically as fast as possible, but it may be
2180 useful during development since you can try to debug
2181 the conditions that lead to the situation.
2183 CONFIG_NET_RETRY_COUNT
2185 This variable defines the number of retries for
2186 network operations like ARP, RARP, TFTP, or BOOTP
2187 before giving up the operation. If not defined, a
2188 default value of 5 is used.
2192 Timeout waiting for an ARP reply in milliseconds.
2196 Timeout in milliseconds used in NFS protocol.
2197 If you encounter "ERROR: Cannot umount" in nfs command,
2198 try longer timeout such as
2199 #define CONFIG_NFS_TIMEOUT 10000UL
2201 - Command Interpreter:
2202 CONFIG_AUTO_COMPLETE
2204 Enable auto completion of commands using TAB.
2206 Note that this feature has NOT been implemented yet
2207 for the "hush" shell.
2210 CONFIG_SYS_HUSH_PARSER
2212 Define this variable to enable the "hush" shell (from
2213 Busybox) as command line interpreter, thus enabling
2214 powerful command line syntax like
2215 if...then...else...fi conditionals or `&&' and '||'
2216 constructs ("shell scripts").
2218 If undefined, you get the old, much simpler behaviour
2219 with a somewhat smaller memory footprint.
2222 CONFIG_SYS_PROMPT_HUSH_PS2
2224 This defines the secondary prompt string, which is
2225 printed when the command interpreter needs more input
2226 to complete a command. Usually "> ".
2230 In the current implementation, the local variables
2231 space and global environment variables space are
2232 separated. Local variables are those you define by
2233 simply typing `name=value'. To access a local
2234 variable later on, you have write `$name' or
2235 `${name}'; to execute the contents of a variable
2236 directly type `$name' at the command prompt.
2238 Global environment variables are those you use
2239 setenv/printenv to work with. To run a command stored
2240 in such a variable, you need to use the run command,
2241 and you must not use the '$' sign to access them.
2243 To store commands and special characters in a
2244 variable, please use double quotation marks
2245 surrounding the whole text of the variable, instead
2246 of the backslashes before semicolons and special
2249 - Commandline Editing and History:
2250 CONFIG_CMDLINE_EDITING
2252 Enable editing and History functions for interactive
2253 commandline input operations
2255 - Default Environment:
2256 CONFIG_EXTRA_ENV_SETTINGS
2258 Define this to contain any number of null terminated
2259 strings (variable = value pairs) that will be part of
2260 the default environment compiled into the boot image.
2262 For example, place something like this in your
2263 board's config file:
2265 #define CONFIG_EXTRA_ENV_SETTINGS \
2269 Warning: This method is based on knowledge about the
2270 internal format how the environment is stored by the
2271 U-Boot code. This is NOT an official, exported
2272 interface! Although it is unlikely that this format
2273 will change soon, there is no guarantee either.
2274 You better know what you are doing here.
2276 Note: overly (ab)use of the default environment is
2277 discouraged. Make sure to check other ways to preset
2278 the environment like the "source" command or the
2281 CONFIG_ENV_VARS_UBOOT_CONFIG
2283 Define this in order to add variables describing the
2284 U-Boot build configuration to the default environment.
2285 These will be named arch, cpu, board, vendor, and soc.
2287 Enabling this option will cause the following to be defined:
2295 - DataFlash Support:
2296 CONFIG_HAS_DATAFLASH
2298 Defining this option enables DataFlash features and
2299 allows to read/write in Dataflash via the standard
2302 - Serial Flash support
2305 Defining this option enables SPI flash commands
2306 'sf probe/read/write/erase/update'.
2308 Usage requires an initial 'probe' to define the serial
2309 flash parameters, followed by read/write/erase/update
2312 The following defaults may be provided by the platform
2313 to handle the common case when only a single serial
2314 flash is present on the system.
2316 CONFIG_SF_DEFAULT_BUS Bus identifier
2317 CONFIG_SF_DEFAULT_CS Chip-select
2318 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2319 CONFIG_SF_DEFAULT_SPEED in Hz
2321 - SystemACE Support:
2324 Adding this option adds support for Xilinx SystemACE
2325 chips attached via some sort of local bus. The address
2326 of the chip must also be defined in the
2327 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2329 #define CONFIG_SYSTEMACE
2330 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2332 When SystemACE support is added, the "ace" device type
2333 becomes available to the fat commands, i.e. fatls.
2335 - TFTP Fixed UDP Port:
2338 If this is defined, the environment variable tftpsrcp
2339 is used to supply the TFTP UDP source port value.
2340 If tftpsrcp isn't defined, the normal pseudo-random port
2341 number generator is used.
2343 Also, the environment variable tftpdstp is used to supply
2344 the TFTP UDP destination port value. If tftpdstp isn't
2345 defined, the normal port 69 is used.
2347 The purpose for tftpsrcp is to allow a TFTP server to
2348 blindly start the TFTP transfer using the pre-configured
2349 target IP address and UDP port. This has the effect of
2350 "punching through" the (Windows XP) firewall, allowing
2351 the remainder of the TFTP transfer to proceed normally.
2352 A better solution is to properly configure the firewall,
2353 but sometimes that is not allowed.
2355 - Show boot progress:
2356 CONFIG_SHOW_BOOT_PROGRESS
2358 Defining this option allows to add some board-
2359 specific code (calling a user-provided function
2360 "show_boot_progress(int)") that enables you to show
2361 the system's boot progress on some display (for
2362 example, some LED's) on your board. At the moment,
2363 the following checkpoints are implemented:
2365 - Detailed boot stage timing
2367 Define this option to get detailed timing of each stage
2368 of the boot process.
2370 CONFIG_BOOTSTAGE_USER_COUNT
2371 This is the number of available user bootstage records.
2372 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2373 a new ID will be allocated from this stash. If you exceed
2374 the limit, recording will stop.
2376 CONFIG_BOOTSTAGE_REPORT
2377 Define this to print a report before boot, similar to this:
2379 Timer summary in microseconds:
2382 3,575,678 3,575,678 board_init_f start
2383 3,575,695 17 arch_cpu_init A9
2384 3,575,777 82 arch_cpu_init done
2385 3,659,598 83,821 board_init_r start
2386 3,910,375 250,777 main_loop
2387 29,916,167 26,005,792 bootm_start
2388 30,361,327 445,160 start_kernel
2390 Legacy uImage format:
2393 1 common/cmd_bootm.c before attempting to boot an image
2394 -1 common/cmd_bootm.c Image header has bad magic number
2395 2 common/cmd_bootm.c Image header has correct magic number
2396 -2 common/cmd_bootm.c Image header has bad checksum
2397 3 common/cmd_bootm.c Image header has correct checksum
2398 -3 common/cmd_bootm.c Image data has bad checksum
2399 4 common/cmd_bootm.c Image data has correct checksum
2400 -4 common/cmd_bootm.c Image is for unsupported architecture
2401 5 common/cmd_bootm.c Architecture check OK
2402 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2403 6 common/cmd_bootm.c Image Type check OK
2404 -6 common/cmd_bootm.c gunzip uncompression error
2405 -7 common/cmd_bootm.c Unimplemented compression type
2406 7 common/cmd_bootm.c Uncompression OK
2407 8 common/cmd_bootm.c No uncompress/copy overwrite error
2408 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2410 9 common/image.c Start initial ramdisk verification
2411 -10 common/image.c Ramdisk header has bad magic number
2412 -11 common/image.c Ramdisk header has bad checksum
2413 10 common/image.c Ramdisk header is OK
2414 -12 common/image.c Ramdisk data has bad checksum
2415 11 common/image.c Ramdisk data has correct checksum
2416 12 common/image.c Ramdisk verification complete, start loading
2417 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2418 13 common/image.c Start multifile image verification
2419 14 common/image.c No initial ramdisk, no multifile, continue.
2421 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2423 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2424 -31 post/post.c POST test failed, detected by post_output_backlog()
2425 -32 post/post.c POST test failed, detected by post_run_single()
2427 34 common/cmd_doc.c before loading a Image from a DOC device
2428 -35 common/cmd_doc.c Bad usage of "doc" command
2429 35 common/cmd_doc.c correct usage of "doc" command
2430 -36 common/cmd_doc.c No boot device
2431 36 common/cmd_doc.c correct boot device
2432 -37 common/cmd_doc.c Unknown Chip ID on boot device
2433 37 common/cmd_doc.c correct chip ID found, device available
2434 -38 common/cmd_doc.c Read Error on boot device
2435 38 common/cmd_doc.c reading Image header from DOC device OK
2436 -39 common/cmd_doc.c Image header has bad magic number
2437 39 common/cmd_doc.c Image header has correct magic number
2438 -40 common/cmd_doc.c Error reading Image from DOC device
2439 40 common/cmd_doc.c Image header has correct magic number
2440 41 common/cmd_ide.c before loading a Image from a IDE device
2441 -42 common/cmd_ide.c Bad usage of "ide" command
2442 42 common/cmd_ide.c correct usage of "ide" command
2443 -43 common/cmd_ide.c No boot device
2444 43 common/cmd_ide.c boot device found
2445 -44 common/cmd_ide.c Device not available
2446 44 common/cmd_ide.c Device available
2447 -45 common/cmd_ide.c wrong partition selected
2448 45 common/cmd_ide.c partition selected
2449 -46 common/cmd_ide.c Unknown partition table
2450 46 common/cmd_ide.c valid partition table found
2451 -47 common/cmd_ide.c Invalid partition type
2452 47 common/cmd_ide.c correct partition type
2453 -48 common/cmd_ide.c Error reading Image Header on boot device
2454 48 common/cmd_ide.c reading Image Header from IDE device OK
2455 -49 common/cmd_ide.c Image header has bad magic number
2456 49 common/cmd_ide.c Image header has correct magic number
2457 -50 common/cmd_ide.c Image header has bad checksum
2458 50 common/cmd_ide.c Image header has correct checksum
2459 -51 common/cmd_ide.c Error reading Image from IDE device
2460 51 common/cmd_ide.c reading Image from IDE device OK
2461 52 common/cmd_nand.c before loading a Image from a NAND device
2462 -53 common/cmd_nand.c Bad usage of "nand" command
2463 53 common/cmd_nand.c correct usage of "nand" command
2464 -54 common/cmd_nand.c No boot device
2465 54 common/cmd_nand.c boot device found
2466 -55 common/cmd_nand.c Unknown Chip ID on boot device
2467 55 common/cmd_nand.c correct chip ID found, device available
2468 -56 common/cmd_nand.c Error reading Image Header on boot device
2469 56 common/cmd_nand.c reading Image Header from NAND device OK
2470 -57 common/cmd_nand.c Image header has bad magic number
2471 57 common/cmd_nand.c Image header has correct magic number
2472 -58 common/cmd_nand.c Error reading Image from NAND device
2473 58 common/cmd_nand.c reading Image from NAND device OK
2475 -60 common/env_common.c Environment has a bad CRC, using default
2477 64 net/eth.c starting with Ethernet configuration.
2478 -64 net/eth.c no Ethernet found.
2479 65 net/eth.c Ethernet found.
2481 -80 common/cmd_net.c usage wrong
2482 80 common/cmd_net.c before calling NetLoop()
2483 -81 common/cmd_net.c some error in NetLoop() occurred
2484 81 common/cmd_net.c NetLoop() back without error
2485 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2486 82 common/cmd_net.c trying automatic boot
2487 83 common/cmd_net.c running "source" command
2488 -83 common/cmd_net.c some error in automatic boot or "source" command
2489 84 common/cmd_net.c end without errors
2494 100 common/cmd_bootm.c Kernel FIT Image has correct format
2495 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2496 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2497 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2498 102 common/cmd_bootm.c Kernel unit name specified
2499 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2500 103 common/cmd_bootm.c Found configuration node
2501 104 common/cmd_bootm.c Got kernel subimage node offset
2502 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2503 105 common/cmd_bootm.c Kernel subimage hash verification OK
2504 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2505 106 common/cmd_bootm.c Architecture check OK
2506 -106 common/cmd_bootm.c Kernel subimage has wrong type
2507 107 common/cmd_bootm.c Kernel subimage type OK
2508 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2509 108 common/cmd_bootm.c Got kernel subimage data/size
2510 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2511 -109 common/cmd_bootm.c Can't get kernel subimage type
2512 -110 common/cmd_bootm.c Can't get kernel subimage comp
2513 -111 common/cmd_bootm.c Can't get kernel subimage os
2514 -112 common/cmd_bootm.c Can't get kernel subimage load address
2515 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2517 120 common/image.c Start initial ramdisk verification
2518 -120 common/image.c Ramdisk FIT image has incorrect format
2519 121 common/image.c Ramdisk FIT image has correct format
2520 122 common/image.c No ramdisk subimage unit name, using configuration
2521 -122 common/image.c Can't get configuration for ramdisk subimage
2522 123 common/image.c Ramdisk unit name specified
2523 -124 common/image.c Can't get ramdisk subimage node offset
2524 125 common/image.c Got ramdisk subimage node offset
2525 -125 common/image.c Ramdisk subimage hash verification failed
2526 126 common/image.c Ramdisk subimage hash verification OK
2527 -126 common/image.c Ramdisk subimage for unsupported architecture
2528 127 common/image.c Architecture check OK
2529 -127 common/image.c Can't get ramdisk subimage data/size
2530 128 common/image.c Got ramdisk subimage data/size
2531 129 common/image.c Can't get ramdisk load address
2532 -129 common/image.c Got ramdisk load address
2534 -130 common/cmd_doc.c Incorrect FIT image format
2535 131 common/cmd_doc.c FIT image format OK
2537 -140 common/cmd_ide.c Incorrect FIT image format
2538 141 common/cmd_ide.c FIT image format OK
2540 -150 common/cmd_nand.c Incorrect FIT image format
2541 151 common/cmd_nand.c FIT image format OK
2543 - Standalone program support:
2544 CONFIG_STANDALONE_LOAD_ADDR
2546 This option defines a board specific value for the
2547 address where standalone program gets loaded, thus
2548 overwriting the architecture dependent default
2551 - Frame Buffer Address:
2554 Define CONFIG_FB_ADDR if you want to use specific
2555 address for frame buffer.
2556 Then system will reserve the frame buffer address to
2557 defined address instead of lcd_setmem (this function
2558 grabs the memory for frame buffer by panel's size).
2560 Please see board_init_f function.
2562 - Automatic software updates via TFTP server
2564 CONFIG_UPDATE_TFTP_CNT_MAX
2565 CONFIG_UPDATE_TFTP_MSEC_MAX
2567 These options enable and control the auto-update feature;
2568 for a more detailed description refer to doc/README.update.
2570 - MTD Support (mtdparts command, UBI support)
2573 Adds the MTD device infrastructure from the Linux kernel.
2574 Needed for mtdparts command support.
2576 CONFIG_MTD_PARTITIONS
2578 Adds the MTD partitioning infrastructure from the Linux
2579 kernel. Needed for UBI support.
2583 Enable building of SPL globally.
2586 LDSCRIPT for linking the SPL binary.
2589 Maximum binary size (text, data and rodata) of the SPL binary.
2591 CONFIG_SPL_TEXT_BASE
2592 TEXT_BASE for linking the SPL binary.
2594 CONFIG_SPL_BSS_START_ADDR
2595 Link address for the BSS within the SPL binary.
2597 CONFIG_SPL_BSS_MAX_SIZE
2598 Maximum binary size of the BSS section of the SPL binary.
2601 Adress of the start of the stack SPL will use
2603 CONFIG_SYS_SPL_MALLOC_START
2604 Starting address of the malloc pool used in SPL.
2606 CONFIG_SYS_SPL_MALLOC_SIZE
2607 The size of the malloc pool used in SPL.
2609 CONFIG_SPL_FRAMEWORK
2610 Enable the SPL framework under common/. This framework
2611 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2612 NAND loading of the Linux Kernel.
2614 CONFIG_SPL_DISPLAY_PRINT
2615 For ARM, enable an optional function to print more information
2616 about the running system.
2618 CONFIG_SPL_LIBCOMMON_SUPPORT
2619 Support for common/libcommon.o in SPL binary
2621 CONFIG_SPL_LIBDISK_SUPPORT
2622 Support for disk/libdisk.o in SPL binary
2624 CONFIG_SPL_I2C_SUPPORT
2625 Support for drivers/i2c/libi2c.o in SPL binary
2627 CONFIG_SPL_GPIO_SUPPORT
2628 Support for drivers/gpio/libgpio.o in SPL binary
2630 CONFIG_SPL_MMC_SUPPORT
2631 Support for drivers/mmc/libmmc.o in SPL binary
2633 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2634 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2635 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2636 Address, size and partition on the MMC to load U-Boot from
2637 when the MMC is being used in raw mode.
2639 CONFIG_SPL_FAT_SUPPORT
2640 Support for fs/fat/libfat.o in SPL binary
2642 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2643 Filename to read to load U-Boot when reading from FAT
2645 CONFIG_SPL_NAND_SIMPLE
2646 Support for drivers/mtd/nand/libnand.o in SPL binary
2648 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2649 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2650 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2651 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2652 CONFIG_SYS_NAND_ECCBYTES
2653 Defines the size and behavior of the NAND that SPL uses
2654 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2656 CONFIG_SYS_NAND_U_BOOT_OFFS
2657 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2660 CONFIG_SYS_NAND_U_BOOT_START
2661 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2664 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2665 Define this if you need to first read the OOB and then the
2666 data. This is used for example on davinci plattforms.
2668 CONFIG_SPL_OMAP3_ID_NAND
2669 Support for an OMAP3-specific set of functions to return the
2670 ID and MFR of the first attached NAND chip, if present.
2672 CONFIG_SPL_SERIAL_SUPPORT
2673 Support for drivers/serial/libserial.o in SPL binary
2675 CONFIG_SPL_SPI_FLASH_SUPPORT
2676 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2678 CONFIG_SPL_SPI_SUPPORT
2679 Support for drivers/spi/libspi.o in SPL binary
2681 CONFIG_SPL_RAM_DEVICE
2682 Support for running image already present in ram, in SPL binary
2684 CONFIG_SPL_LIBGENERIC_SUPPORT
2685 Support for lib/libgeneric.o in SPL binary
2690 [so far only for SMDK2400 boards]
2692 - Modem support enable:
2693 CONFIG_MODEM_SUPPORT
2695 - RTS/CTS Flow control enable:
2698 - Modem debug support:
2699 CONFIG_MODEM_SUPPORT_DEBUG
2701 Enables debugging stuff (char screen[1024], dbg())
2702 for modem support. Useful only with BDI2000.
2704 - Interrupt support (PPC):
2706 There are common interrupt_init() and timer_interrupt()
2707 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2708 for CPU specific initialization. interrupt_init_cpu()
2709 should set decrementer_count to appropriate value. If
2710 CPU resets decrementer automatically after interrupt
2711 (ppc4xx) it should set decrementer_count to zero.
2712 timer_interrupt() calls timer_interrupt_cpu() for CPU
2713 specific handling. If board has watchdog / status_led
2714 / other_activity_monitor it works automatically from
2715 general timer_interrupt().
2719 In the target system modem support is enabled when a
2720 specific key (key combination) is pressed during
2721 power-on. Otherwise U-Boot will boot normally
2722 (autoboot). The key_pressed() function is called from
2723 board_init(). Currently key_pressed() is a dummy
2724 function, returning 1 and thus enabling modem
2727 If there are no modem init strings in the
2728 environment, U-Boot proceed to autoboot; the
2729 previous output (banner, info printfs) will be
2732 See also: doc/README.Modem
2734 Board initialization settings:
2735 ------------------------------
2737 During Initialization u-boot calls a number of board specific functions
2738 to allow the preparation of board specific prerequisites, e.g. pin setup
2739 before drivers are initialized. To enable these callbacks the
2740 following configuration macros have to be defined. Currently this is
2741 architecture specific, so please check arch/your_architecture/lib/board.c
2742 typically in board_init_f() and board_init_r().
2744 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2745 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2746 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2747 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2749 Configuration Settings:
2750 -----------------------
2752 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2753 undefine this when you're short of memory.
2755 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2756 width of the commands listed in the 'help' command output.
2758 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2759 prompt for user input.
2761 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2763 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2765 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2767 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2768 the application (usually a Linux kernel) when it is
2771 - CONFIG_SYS_BAUDRATE_TABLE:
2772 List of legal baudrate settings for this board.
2774 - CONFIG_SYS_CONSOLE_INFO_QUIET
2775 Suppress display of console information at boot.
2777 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2778 If the board specific function
2779 extern int overwrite_console (void);
2780 returns 1, the stdin, stderr and stdout are switched to the
2781 serial port, else the settings in the environment are used.
2783 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2784 Enable the call to overwrite_console().
2786 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2787 Enable overwrite of previous console environment settings.
2789 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2790 Begin and End addresses of the area used by the
2793 - CONFIG_SYS_ALT_MEMTEST:
2794 Enable an alternate, more extensive memory test.
2796 - CONFIG_SYS_MEMTEST_SCRATCH:
2797 Scratch address used by the alternate memory test
2798 You only need to set this if address zero isn't writeable
2800 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2801 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2802 this specified memory area will get subtracted from the top
2803 (end) of RAM and won't get "touched" at all by U-Boot. By
2804 fixing up gd->ram_size the Linux kernel should gets passed
2805 the now "corrected" memory size and won't touch it either.
2806 This should work for arch/ppc and arch/powerpc. Only Linux
2807 board ports in arch/powerpc with bootwrapper support that
2808 recalculate the memory size from the SDRAM controller setup
2809 will have to get fixed in Linux additionally.
2811 This option can be used as a workaround for the 440EPx/GRx
2812 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2815 WARNING: Please make sure that this value is a multiple of
2816 the Linux page size (normally 4k). If this is not the case,
2817 then the end address of the Linux memory will be located at a
2818 non page size aligned address and this could cause major
2821 - CONFIG_SYS_TFTP_LOADADDR:
2822 Default load address for network file downloads
2824 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2825 Enable temporary baudrate change while serial download
2827 - CONFIG_SYS_SDRAM_BASE:
2828 Physical start address of SDRAM. _Must_ be 0 here.
2830 - CONFIG_SYS_MBIO_BASE:
2831 Physical start address of Motherboard I/O (if using a
2834 - CONFIG_SYS_FLASH_BASE:
2835 Physical start address of Flash memory.
2837 - CONFIG_SYS_MONITOR_BASE:
2838 Physical start address of boot monitor code (set by
2839 make config files to be same as the text base address
2840 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2841 CONFIG_SYS_FLASH_BASE when booting from flash.
2843 - CONFIG_SYS_MONITOR_LEN:
2844 Size of memory reserved for monitor code, used to
2845 determine _at_compile_time_ (!) if the environment is
2846 embedded within the U-Boot image, or in a separate
2849 - CONFIG_SYS_MALLOC_LEN:
2850 Size of DRAM reserved for malloc() use.
2852 - CONFIG_SYS_BOOTM_LEN:
2853 Normally compressed uImages are limited to an
2854 uncompressed size of 8 MBytes. If this is not enough,
2855 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2856 to adjust this setting to your needs.
2858 - CONFIG_SYS_BOOTMAPSZ:
2859 Maximum size of memory mapped by the startup code of
2860 the Linux kernel; all data that must be processed by
2861 the Linux kernel (bd_info, boot arguments, FDT blob if
2862 used) must be put below this limit, unless "bootm_low"
2863 enviroment variable is defined and non-zero. In such case
2864 all data for the Linux kernel must be between "bootm_low"
2865 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2866 variable "bootm_mapsize" will override the value of
2867 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2868 then the value in "bootm_size" will be used instead.
2870 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2871 Enable initrd_high functionality. If defined then the
2872 initrd_high feature is enabled and the bootm ramdisk subcommand
2875 - CONFIG_SYS_BOOT_GET_CMDLINE:
2876 Enables allocating and saving kernel cmdline in space between
2877 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2879 - CONFIG_SYS_BOOT_GET_KBD:
2880 Enables allocating and saving a kernel copy of the bd_info in
2881 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2883 - CONFIG_SYS_MAX_FLASH_BANKS:
2884 Max number of Flash memory banks
2886 - CONFIG_SYS_MAX_FLASH_SECT:
2887 Max number of sectors on a Flash chip
2889 - CONFIG_SYS_FLASH_ERASE_TOUT:
2890 Timeout for Flash erase operations (in ms)
2892 - CONFIG_SYS_FLASH_WRITE_TOUT:
2893 Timeout for Flash write operations (in ms)
2895 - CONFIG_SYS_FLASH_LOCK_TOUT
2896 Timeout for Flash set sector lock bit operation (in ms)
2898 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2899 Timeout for Flash clear lock bits operation (in ms)
2901 - CONFIG_SYS_FLASH_PROTECTION
2902 If defined, hardware flash sectors protection is used
2903 instead of U-Boot software protection.
2905 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2907 Enable TFTP transfers directly to flash memory;
2908 without this option such a download has to be
2909 performed in two steps: (1) download to RAM, and (2)
2910 copy from RAM to flash.
2912 The two-step approach is usually more reliable, since
2913 you can check if the download worked before you erase
2914 the flash, but in some situations (when system RAM is
2915 too limited to allow for a temporary copy of the
2916 downloaded image) this option may be very useful.
2918 - CONFIG_SYS_FLASH_CFI:
2919 Define if the flash driver uses extra elements in the
2920 common flash structure for storing flash geometry.
2922 - CONFIG_FLASH_CFI_DRIVER
2923 This option also enables the building of the cfi_flash driver
2924 in the drivers directory
2926 - CONFIG_FLASH_CFI_MTD
2927 This option enables the building of the cfi_mtd driver
2928 in the drivers directory. The driver exports CFI flash
2931 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2932 Use buffered writes to flash.
2934 - CONFIG_FLASH_SPANSION_S29WS_N
2935 s29ws-n MirrorBit flash has non-standard addresses for buffered
2938 - CONFIG_SYS_FLASH_QUIET_TEST
2939 If this option is defined, the common CFI flash doesn't
2940 print it's warning upon not recognized FLASH banks. This
2941 is useful, if some of the configured banks are only
2942 optionally available.
2944 - CONFIG_FLASH_SHOW_PROGRESS
2945 If defined (must be an integer), print out countdown
2946 digits and dots. Recommended value: 45 (9..1) for 80
2947 column displays, 15 (3..1) for 40 column displays.
2949 - CONFIG_SYS_RX_ETH_BUFFER:
2950 Defines the number of Ethernet receive buffers. On some
2951 Ethernet controllers it is recommended to set this value
2952 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2953 buffers can be full shortly after enabling the interface
2954 on high Ethernet traffic.
2955 Defaults to 4 if not defined.
2957 - CONFIG_ENV_MAX_ENTRIES
2959 Maximum number of entries in the hash table that is used
2960 internally to store the environment settings. The default
2961 setting is supposed to be generous and should work in most
2962 cases. This setting can be used to tune behaviour; see
2963 lib/hashtable.c for details.
2965 The following definitions that deal with the placement and management
2966 of environment data (variable area); in general, we support the
2967 following configurations:
2969 - CONFIG_BUILD_ENVCRC:
2971 Builds up envcrc with the target environment so that external utils
2972 may easily extract it and embed it in final U-Boot images.
2974 - CONFIG_ENV_IS_IN_FLASH:
2976 Define this if the environment is in flash memory.
2978 a) The environment occupies one whole flash sector, which is
2979 "embedded" in the text segment with the U-Boot code. This
2980 happens usually with "bottom boot sector" or "top boot
2981 sector" type flash chips, which have several smaller
2982 sectors at the start or the end. For instance, such a
2983 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2984 such a case you would place the environment in one of the
2985 4 kB sectors - with U-Boot code before and after it. With
2986 "top boot sector" type flash chips, you would put the
2987 environment in one of the last sectors, leaving a gap
2988 between U-Boot and the environment.
2990 - CONFIG_ENV_OFFSET:
2992 Offset of environment data (variable area) to the
2993 beginning of flash memory; for instance, with bottom boot
2994 type flash chips the second sector can be used: the offset
2995 for this sector is given here.
2997 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3001 This is just another way to specify the start address of
3002 the flash sector containing the environment (instead of
3005 - CONFIG_ENV_SECT_SIZE:
3007 Size of the sector containing the environment.
3010 b) Sometimes flash chips have few, equal sized, BIG sectors.
3011 In such a case you don't want to spend a whole sector for
3016 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3017 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3018 of this flash sector for the environment. This saves
3019 memory for the RAM copy of the environment.
3021 It may also save flash memory if you decide to use this
3022 when your environment is "embedded" within U-Boot code,
3023 since then the remainder of the flash sector could be used
3024 for U-Boot code. It should be pointed out that this is
3025 STRONGLY DISCOURAGED from a robustness point of view:
3026 updating the environment in flash makes it always
3027 necessary to erase the WHOLE sector. If something goes
3028 wrong before the contents has been restored from a copy in
3029 RAM, your target system will be dead.
3031 - CONFIG_ENV_ADDR_REDUND
3032 CONFIG_ENV_SIZE_REDUND
3034 These settings describe a second storage area used to hold
3035 a redundant copy of the environment data, so that there is
3036 a valid backup copy in case there is a power failure during
3037 a "saveenv" operation.
3039 BE CAREFUL! Any changes to the flash layout, and some changes to the
3040 source code will make it necessary to adapt <board>/u-boot.lds*
3044 - CONFIG_ENV_IS_IN_NVRAM:
3046 Define this if you have some non-volatile memory device
3047 (NVRAM, battery buffered SRAM) which you want to use for the
3053 These two #defines are used to determine the memory area you
3054 want to use for environment. It is assumed that this memory
3055 can just be read and written to, without any special
3058 BE CAREFUL! The first access to the environment happens quite early
3059 in U-Boot initalization (when we try to get the setting of for the
3060 console baudrate). You *MUST* have mapped your NVRAM area then, or
3063 Please note that even with NVRAM we still use a copy of the
3064 environment in RAM: we could work on NVRAM directly, but we want to
3065 keep settings there always unmodified except somebody uses "saveenv"
3066 to save the current settings.
3069 - CONFIG_ENV_IS_IN_EEPROM:
3071 Use this if you have an EEPROM or similar serial access
3072 device and a driver for it.
3074 - CONFIG_ENV_OFFSET:
3077 These two #defines specify the offset and size of the
3078 environment area within the total memory of your EEPROM.
3080 - CONFIG_SYS_I2C_EEPROM_ADDR:
3081 If defined, specified the chip address of the EEPROM device.
3082 The default address is zero.
3084 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3085 If defined, the number of bits used to address bytes in a
3086 single page in the EEPROM device. A 64 byte page, for example
3087 would require six bits.
3089 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3090 If defined, the number of milliseconds to delay between
3091 page writes. The default is zero milliseconds.
3093 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3094 The length in bytes of the EEPROM memory array address. Note
3095 that this is NOT the chip address length!
3097 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3098 EEPROM chips that implement "address overflow" are ones
3099 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3100 address and the extra bits end up in the "chip address" bit
3101 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3104 Note that we consider the length of the address field to
3105 still be one byte because the extra address bits are hidden
3106 in the chip address.
3108 - CONFIG_SYS_EEPROM_SIZE:
3109 The size in bytes of the EEPROM device.
3111 - CONFIG_ENV_EEPROM_IS_ON_I2C
3112 define this, if you have I2C and SPI activated, and your
3113 EEPROM, which holds the environment, is on the I2C bus.
3115 - CONFIG_I2C_ENV_EEPROM_BUS
3116 if you have an Environment on an EEPROM reached over
3117 I2C muxes, you can define here, how to reach this
3118 EEPROM. For example:
3120 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3122 EEPROM which holds the environment, is reached over
3123 a pca9547 i2c mux with address 0x70, channel 3.
3125 - CONFIG_ENV_IS_IN_DATAFLASH:
3127 Define this if you have a DataFlash memory device which you
3128 want to use for the environment.
3130 - CONFIG_ENV_OFFSET:
3134 These three #defines specify the offset and size of the
3135 environment area within the total memory of your DataFlash placed
3136 at the specified address.
3138 - CONFIG_ENV_IS_IN_REMOTE:
3140 Define this if you have a remote memory space which you
3141 want to use for the local device's environment.
3146 These two #defines specify the address and size of the
3147 environment area within the remote memory space. The
3148 local device can get the environment from remote memory
3149 space by SRIO or PCIE links.
3151 BE CAREFUL! For some special cases, the local device can not use
3152 "saveenv" command. For example, the local device will get the
3153 environment stored in a remote NOR flash by SRIO or PCIE link,
3154 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3156 - CONFIG_ENV_IS_IN_NAND:
3158 Define this if you have a NAND device which you want to use
3159 for the environment.
3161 - CONFIG_ENV_OFFSET:
3164 These two #defines specify the offset and size of the environment
3165 area within the first NAND device. CONFIG_ENV_OFFSET must be
3166 aligned to an erase block boundary.
3168 - CONFIG_ENV_OFFSET_REDUND (optional):
3170 This setting describes a second storage area of CONFIG_ENV_SIZE
3171 size used to hold a redundant copy of the environment data, so
3172 that there is a valid backup copy in case there is a power failure
3173 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3174 aligned to an erase block boundary.
3176 - CONFIG_ENV_RANGE (optional):
3178 Specifies the length of the region in which the environment
3179 can be written. This should be a multiple of the NAND device's
3180 block size. Specifying a range with more erase blocks than
3181 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3182 the range to be avoided.
3184 - CONFIG_ENV_OFFSET_OOB (optional):
3186 Enables support for dynamically retrieving the offset of the
3187 environment from block zero's out-of-band data. The
3188 "nand env.oob" command can be used to record this offset.
3189 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3190 using CONFIG_ENV_OFFSET_OOB.
3192 - CONFIG_NAND_ENV_DST
3194 Defines address in RAM to which the nand_spl code should copy the
3195 environment. If redundant environment is used, it will be copied to
3196 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3198 - CONFIG_SYS_SPI_INIT_OFFSET
3200 Defines offset to the initial SPI buffer area in DPRAM. The
3201 area is used at an early stage (ROM part) if the environment
3202 is configured to reside in the SPI EEPROM: We need a 520 byte
3203 scratch DPRAM area. It is used between the two initialization
3204 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3205 to be a good choice since it makes it far enough from the
3206 start of the data area as well as from the stack pointer.
3208 Please note that the environment is read-only until the monitor
3209 has been relocated to RAM and a RAM copy of the environment has been
3210 created; also, when using EEPROM you will have to use getenv_f()
3211 until then to read environment variables.
3213 The environment is protected by a CRC32 checksum. Before the monitor
3214 is relocated into RAM, as a result of a bad CRC you will be working
3215 with the compiled-in default environment - *silently*!!! [This is
3216 necessary, because the first environment variable we need is the
3217 "baudrate" setting for the console - if we have a bad CRC, we don't
3218 have any device yet where we could complain.]
3220 Note: once the monitor has been relocated, then it will complain if
3221 the default environment is used; a new CRC is computed as soon as you
3222 use the "saveenv" command to store a valid environment.
3224 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3225 Echo the inverted Ethernet link state to the fault LED.
3227 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3228 also needs to be defined.
3230 - CONFIG_SYS_FAULT_MII_ADDR:
3231 MII address of the PHY to check for the Ethernet link state.
3233 - CONFIG_NS16550_MIN_FUNCTIONS:
3234 Define this if you desire to only have use of the NS16550_init
3235 and NS16550_putc functions for the serial driver located at
3236 drivers/serial/ns16550.c. This option is useful for saving
3237 space for already greatly restricted images, including but not
3238 limited to NAND_SPL configurations.
3240 Low Level (hardware related) configuration options:
3241 ---------------------------------------------------
3243 - CONFIG_SYS_CACHELINE_SIZE:
3244 Cache Line Size of the CPU.
3246 - CONFIG_SYS_DEFAULT_IMMR:
3247 Default address of the IMMR after system reset.
3249 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3250 and RPXsuper) to be able to adjust the position of
3251 the IMMR register after a reset.
3253 - CONFIG_SYS_CCSRBAR_DEFAULT:
3254 Default (power-on reset) physical address of CCSR on Freescale
3257 - CONFIG_SYS_CCSRBAR:
3258 Virtual address of CCSR. On a 32-bit build, this is typically
3259 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3261 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3262 for cross-platform code that uses that macro instead.
3264 - CONFIG_SYS_CCSRBAR_PHYS:
3265 Physical address of CCSR. CCSR can be relocated to a new
3266 physical address, if desired. In this case, this macro should
3267 be set to that address. Otherwise, it should be set to the
3268 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3269 is typically relocated on 36-bit builds. It is recommended
3270 that this macro be defined via the _HIGH and _LOW macros:
3272 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3273 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3275 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3276 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3277 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3278 used in assembly code, so it must not contain typecasts or
3279 integer size suffixes (e.g. "ULL").
3281 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3282 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3283 used in assembly code, so it must not contain typecasts or
3284 integer size suffixes (e.g. "ULL").
3286 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3287 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3288 forced to a value that ensures that CCSR is not relocated.
3290 - Floppy Disk Support:
3291 CONFIG_SYS_FDC_DRIVE_NUMBER
3293 the default drive number (default value 0)
3295 CONFIG_SYS_ISA_IO_STRIDE
3297 defines the spacing between FDC chipset registers
3300 CONFIG_SYS_ISA_IO_OFFSET
3302 defines the offset of register from address. It
3303 depends on which part of the data bus is connected to
3304 the FDC chipset. (default value 0)
3306 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3307 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3310 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3311 fdc_hw_init() is called at the beginning of the FDC
3312 setup. fdc_hw_init() must be provided by the board
3313 source code. It is used to make hardware dependant
3317 Most IDE controllers were designed to be connected with PCI
3318 interface. Only few of them were designed for AHB interface.
3319 When software is doing ATA command and data transfer to
3320 IDE devices through IDE-AHB controller, some additional
3321 registers accessing to these kind of IDE-AHB controller
3324 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3325 DO NOT CHANGE unless you know exactly what you're
3326 doing! (11-4) [MPC8xx/82xx systems only]
3328 - CONFIG_SYS_INIT_RAM_ADDR:
3330 Start address of memory area that can be used for
3331 initial data and stack; please note that this must be
3332 writable memory that is working WITHOUT special
3333 initialization, i. e. you CANNOT use normal RAM which
3334 will become available only after programming the
3335 memory controller and running certain initialization
3338 U-Boot uses the following memory types:
3339 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3340 - MPC824X: data cache
3341 - PPC4xx: data cache
3343 - CONFIG_SYS_GBL_DATA_OFFSET:
3345 Offset of the initial data structure in the memory
3346 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3347 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3348 data is located at the end of the available space
3349 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3350 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3351 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3352 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3355 On the MPC824X (or other systems that use the data
3356 cache for initial memory) the address chosen for
3357 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3358 point to an otherwise UNUSED address space between
3359 the top of RAM and the start of the PCI space.
3361 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3363 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3365 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3367 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3369 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3371 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3373 - CONFIG_SYS_OR_TIMING_SDRAM:
3376 - CONFIG_SYS_MAMR_PTA:
3377 periodic timer for refresh
3379 - CONFIG_SYS_DER: Debug Event Register (37-47)
3381 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3382 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3383 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3384 CONFIG_SYS_BR1_PRELIM:
3385 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3387 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3388 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3389 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3390 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3392 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3393 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3394 Machine Mode Register and Memory Periodic Timer
3395 Prescaler definitions (SDRAM timing)
3397 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3398 enable I2C microcode relocation patch (MPC8xx);
3399 define relocation offset in DPRAM [DSP2]
3401 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3402 enable SMC microcode relocation patch (MPC8xx);
3403 define relocation offset in DPRAM [SMC1]
3405 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3406 enable SPI microcode relocation patch (MPC8xx);
3407 define relocation offset in DPRAM [SCC4]
3409 - CONFIG_SYS_USE_OSCCLK:
3410 Use OSCM clock mode on MBX8xx board. Be careful,
3411 wrong setting might damage your board. Read
3412 doc/README.MBX before setting this variable!
3414 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3415 Offset of the bootmode word in DPRAM used by post
3416 (Power On Self Tests). This definition overrides
3417 #define'd default value in commproc.h resp.
3420 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3421 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3422 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3423 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3424 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3425 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3426 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3427 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3428 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3430 - CONFIG_PCI_DISABLE_PCIE:
3431 Disable PCI-Express on systems where it is supported but not
3434 - CONFIG_PCI_ENUM_ONLY
3435 Only scan through and get the devices on the busses.
3436 Don't do any setup work, presumably because someone or
3437 something has already done it, and we don't need to do it
3438 a second time. Useful for platforms that are pre-booted
3439 by coreboot or similar.
3442 Chip has SRIO or not
3445 Board has SRIO 1 port available
3448 Board has SRIO 2 port available
3450 - CONFIG_SYS_SRIOn_MEM_VIRT:
3451 Virtual Address of SRIO port 'n' memory region
3453 - CONFIG_SYS_SRIOn_MEM_PHYS:
3454 Physical Address of SRIO port 'n' memory region
3456 - CONFIG_SYS_SRIOn_MEM_SIZE:
3457 Size of SRIO port 'n' memory region
3459 - CONFIG_SYS_NDFC_16
3460 Defined to tell the NDFC that the NAND chip is using a
3463 - CONFIG_SYS_NDFC_EBC0_CFG
3464 Sets the EBC0_CFG register for the NDFC. If not defined
3465 a default value will be used.
3468 Get DDR timing information from an I2C EEPROM. Common
3469 with pluggable memory modules such as SODIMMs
3472 I2C address of the SPD EEPROM
3474 - CONFIG_SYS_SPD_BUS_NUM
3475 If SPD EEPROM is on an I2C bus other than the first
3476 one, specify here. Note that the value must resolve
3477 to something your driver can deal with.
3479 - CONFIG_SYS_DDR_RAW_TIMING
3480 Get DDR timing information from other than SPD. Common with
3481 soldered DDR chips onboard without SPD. DDR raw timing
3482 parameters are extracted from datasheet and hard-coded into
3483 header files or board specific files.
3485 - CONFIG_FSL_DDR_INTERACTIVE
3486 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3488 - CONFIG_SYS_83XX_DDR_USES_CS0
3489 Only for 83xx systems. If specified, then DDR should
3490 be configured using CS0 and CS1 instead of CS2 and CS3.
3492 - CONFIG_ETHER_ON_FEC[12]
3493 Define to enable FEC[12] on a 8xx series processor.
3495 - CONFIG_FEC[12]_PHY
3496 Define to the hardcoded PHY address which corresponds
3497 to the given FEC; i. e.
3498 #define CONFIG_FEC1_PHY 4
3499 means that the PHY with address 4 is connected to FEC1
3501 When set to -1, means to probe for first available.
3503 - CONFIG_FEC[12]_PHY_NORXERR
3504 The PHY does not have a RXERR line (RMII only).
3505 (so program the FEC to ignore it).
3508 Enable RMII mode for all FECs.
3509 Note that this is a global option, we can't
3510 have one FEC in standard MII mode and another in RMII mode.
3512 - CONFIG_CRC32_VERIFY
3513 Add a verify option to the crc32 command.
3516 => crc32 -v <address> <count> <crc32>
3518 Where address/count indicate a memory area
3519 and crc32 is the correct crc32 which the
3523 Add the "loopw" memory command. This only takes effect if
3524 the memory commands are activated globally (CONFIG_CMD_MEM).
3527 Add the "mdc" and "mwc" memory commands. These are cyclic
3532 This command will print 4 bytes (10,11,12,13) each 500 ms.
3534 => mwc.l 100 12345678 10
3535 This command will write 12345678 to address 100 all 10 ms.
3537 This only takes effect if the memory commands are activated
3538 globally (CONFIG_CMD_MEM).
3540 - CONFIG_SKIP_LOWLEVEL_INIT
3541 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3542 low level initializations (like setting up the memory
3543 controller) are omitted and/or U-Boot does not
3544 relocate itself into RAM.
3546 Normally this variable MUST NOT be defined. The only
3547 exception is when U-Boot is loaded (to RAM) by some
3548 other boot loader or by a debugger which performs
3549 these initializations itself.
3552 Modifies the behaviour of start.S when compiling a loader
3553 that is executed before the actual U-Boot. E.g. when
3554 compiling a NAND SPL.
3556 - CONFIG_USE_ARCH_MEMCPY
3557 CONFIG_USE_ARCH_MEMSET
3558 If these options are used a optimized version of memcpy/memset will
3559 be used if available. These functions may be faster under some
3560 conditions but may increase the binary size.
3562 Freescale QE/FMAN Firmware Support:
3563 -----------------------------------
3565 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3566 loading of "firmware", which is encoded in the QE firmware binary format.
3567 This firmware often needs to be loaded during U-Boot booting, so macros
3568 are used to identify the storage device (NOR flash, SPI, etc) and the address
3571 - CONFIG_SYS_QE_FMAN_FW_ADDR
3572 The address in the storage device where the firmware is located. The
3573 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3576 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3577 The maximum possible size of the firmware. The firmware binary format
3578 has a field that specifies the actual size of the firmware, but it
3579 might not be possible to read any part of the firmware unless some
3580 local storage is allocated to hold the entire firmware first.
3582 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3583 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3584 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3585 virtual address in NOR flash.
3587 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3588 Specifies that QE/FMAN firmware is located in NAND flash.
3589 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3591 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3592 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3593 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3595 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3596 Specifies that QE/FMAN firmware is located on the primary SPI
3597 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3599 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3600 Specifies that QE/FMAN firmware is located in the remote (master)
3601 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3602 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3603 window->master inbound window->master LAW->the ucode address in
3604 master's memory space.
3606 Building the Software:
3607 ======================
3609 Building U-Boot has been tested in several native build environments
3610 and in many different cross environments. Of course we cannot support
3611 all possibly existing versions of cross development tools in all
3612 (potentially obsolete) versions. In case of tool chain problems we
3613 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3614 which is extensively used to build and test U-Boot.
3616 If you are not using a native environment, it is assumed that you
3617 have GNU cross compiling tools available in your path. In this case,
3618 you must set the environment variable CROSS_COMPILE in your shell.
3619 Note that no changes to the Makefile or any other source files are
3620 necessary. For example using the ELDK on a 4xx CPU, please enter:
3622 $ CROSS_COMPILE=ppc_4xx-
3623 $ export CROSS_COMPILE
3625 Note: If you wish to generate Windows versions of the utilities in
3626 the tools directory you can use the MinGW toolchain
3627 (http://www.mingw.org). Set your HOST tools to the MinGW
3628 toolchain and execute 'make tools'. For example:
3630 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3632 Binaries such as tools/mkimage.exe will be created which can
3633 be executed on computers running Windows.
3635 U-Boot is intended to be simple to build. After installing the
3636 sources you must configure U-Boot for one specific board type. This
3641 where "NAME_config" is the name of one of the existing configu-
3642 rations; see boards.cfg for supported names.
3644 Note: for some board special configuration names may exist; check if
3645 additional information is available from the board vendor; for
3646 instance, the TQM823L systems are available without (standard)
3647 or with LCD support. You can select such additional "features"
3648 when choosing the configuration, i. e.
3651 - will configure for a plain TQM823L, i. e. no LCD support
3653 make TQM823L_LCD_config
3654 - will configure for a TQM823L with U-Boot console on LCD
3659 Finally, type "make all", and you should get some working U-Boot
3660 images ready for download to / installation on your system:
3662 - "u-boot.bin" is a raw binary image
3663 - "u-boot" is an image in ELF binary format
3664 - "u-boot.srec" is in Motorola S-Record format
3666 By default the build is performed locally and the objects are saved
3667 in the source directory. One of the two methods can be used to change
3668 this behavior and build U-Boot to some external directory:
3670 1. Add O= to the make command line invocations:
3672 make O=/tmp/build distclean
3673 make O=/tmp/build NAME_config
3674 make O=/tmp/build all
3676 2. Set environment variable BUILD_DIR to point to the desired location:
3678 export BUILD_DIR=/tmp/build
3683 Note that the command line "O=" setting overrides the BUILD_DIR environment
3687 Please be aware that the Makefiles assume you are using GNU make, so
3688 for instance on NetBSD you might need to use "gmake" instead of
3692 If the system board that you have is not listed, then you will need
3693 to port U-Boot to your hardware platform. To do this, follow these
3696 1. Add a new configuration option for your board to the toplevel
3697 "boards.cfg" file, using the existing entries as examples.
3698 Follow the instructions there to keep the boards in order.
3699 2. Create a new directory to hold your board specific code. Add any
3700 files you need. In your board directory, you will need at least
3701 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3702 3. Create a new configuration file "include/configs/<board>.h" for
3704 3. If you're porting U-Boot to a new CPU, then also create a new
3705 directory to hold your CPU specific code. Add any files you need.
3706 4. Run "make <board>_config" with your new name.
3707 5. Type "make", and you should get a working "u-boot.srec" file
3708 to be installed on your target system.
3709 6. Debug and solve any problems that might arise.
3710 [Of course, this last step is much harder than it sounds.]
3713 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3714 ==============================================================
3716 If you have modified U-Boot sources (for instance added a new board
3717 or support for new devices, a new CPU, etc.) you are expected to
3718 provide feedback to the other developers. The feedback normally takes
3719 the form of a "patch", i. e. a context diff against a certain (latest
3720 official or latest in the git repository) version of U-Boot sources.
3722 But before you submit such a patch, please verify that your modifi-
3723 cation did not break existing code. At least make sure that *ALL* of
3724 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3725 just run the "MAKEALL" script, which will configure and build U-Boot
3726 for ALL supported system. Be warned, this will take a while. You can
3727 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3728 environment variable to the script, i. e. to use the ELDK cross tools
3731 CROSS_COMPILE=ppc_8xx- MAKEALL
3733 or to build on a native PowerPC system you can type
3735 CROSS_COMPILE=' ' MAKEALL
3737 When using the MAKEALL script, the default behaviour is to build
3738 U-Boot in the source directory. This location can be changed by
3739 setting the BUILD_DIR environment variable. Also, for each target
3740 built, the MAKEALL script saves two log files (<target>.ERR and
3741 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3742 location can be changed by setting the MAKEALL_LOGDIR environment
3743 variable. For example:
3745 export BUILD_DIR=/tmp/build
3746 export MAKEALL_LOGDIR=/tmp/log
3747 CROSS_COMPILE=ppc_8xx- MAKEALL
3749 With the above settings build objects are saved in the /tmp/build,
3750 log files are saved in the /tmp/log and the source tree remains clean
3751 during the whole build process.
3754 See also "U-Boot Porting Guide" below.
3757 Monitor Commands - Overview:
3758 ============================
3760 go - start application at address 'addr'
3761 run - run commands in an environment variable
3762 bootm - boot application image from memory
3763 bootp - boot image via network using BootP/TFTP protocol
3764 bootz - boot zImage from memory
3765 tftpboot- boot image via network using TFTP protocol
3766 and env variables "ipaddr" and "serverip"
3767 (and eventually "gatewayip")
3768 tftpput - upload a file via network using TFTP protocol
3769 rarpboot- boot image via network using RARP/TFTP protocol
3770 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3771 loads - load S-Record file over serial line
3772 loadb - load binary file over serial line (kermit mode)
3774 mm - memory modify (auto-incrementing)
3775 nm - memory modify (constant address)
3776 mw - memory write (fill)
3778 cmp - memory compare
3779 crc32 - checksum calculation
3780 i2c - I2C sub-system
3781 sspi - SPI utility commands
3782 base - print or set address offset
3783 printenv- print environment variables
3784 setenv - set environment variables
3785 saveenv - save environment variables to persistent storage
3786 protect - enable or disable FLASH write protection
3787 erase - erase FLASH memory
3788 flinfo - print FLASH memory information
3789 bdinfo - print Board Info structure
3790 iminfo - print header information for application image
3791 coninfo - print console devices and informations
3792 ide - IDE sub-system
3793 loop - infinite loop on address range
3794 loopw - infinite write loop on address range
3795 mtest - simple RAM test
3796 icache - enable or disable instruction cache
3797 dcache - enable or disable data cache
3798 reset - Perform RESET of the CPU
3799 echo - echo args to console
3800 version - print monitor version
3801 help - print online help
3802 ? - alias for 'help'
3805 Monitor Commands - Detailed Description:
3806 ========================================
3810 For now: just type "help <command>".
3813 Environment Variables:
3814 ======================
3816 U-Boot supports user configuration using Environment Variables which
3817 can be made persistent by saving to Flash memory.
3819 Environment Variables are set using "setenv", printed using
3820 "printenv", and saved to Flash using "saveenv". Using "setenv"
3821 without a value can be used to delete a variable from the
3822 environment. As long as you don't save the environment you are
3823 working with an in-memory copy. In case the Flash area containing the
3824 environment is erased by accident, a default environment is provided.
3826 Some configuration options can be set using Environment Variables.
3828 List of environment variables (most likely not complete):
3830 baudrate - see CONFIG_BAUDRATE
3832 bootdelay - see CONFIG_BOOTDELAY
3834 bootcmd - see CONFIG_BOOTCOMMAND
3836 bootargs - Boot arguments when booting an RTOS image
3838 bootfile - Name of the image to load with TFTP
3840 bootm_low - Memory range available for image processing in the bootm
3841 command can be restricted. This variable is given as
3842 a hexadecimal number and defines lowest address allowed
3843 for use by the bootm command. See also "bootm_size"
3844 environment variable. Address defined by "bootm_low" is
3845 also the base of the initial memory mapping for the Linux
3846 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3849 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3850 This variable is given as a hexadecimal number and it
3851 defines the size of the memory region starting at base
3852 address bootm_low that is accessible by the Linux kernel
3853 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3854 as the default value if it is defined, and bootm_size is
3857 bootm_size - Memory range available for image processing in the bootm
3858 command can be restricted. This variable is given as
3859 a hexadecimal number and defines the size of the region
3860 allowed for use by the bootm command. See also "bootm_low"
3861 environment variable.
3863 updatefile - Location of the software update file on a TFTP server, used
3864 by the automatic software update feature. Please refer to
3865 documentation in doc/README.update for more details.
3867 autoload - if set to "no" (any string beginning with 'n'),
3868 "bootp" will just load perform a lookup of the
3869 configuration from the BOOTP server, but not try to
3870 load any image using TFTP
3872 autostart - if set to "yes", an image loaded using the "bootp",
3873 "rarpboot", "tftpboot" or "diskboot" commands will
3874 be automatically started (by internally calling
3877 If set to "no", a standalone image passed to the
3878 "bootm" command will be copied to the load address
3879 (and eventually uncompressed), but NOT be started.
3880 This can be used to load and uncompress arbitrary
3883 fdt_high - if set this restricts the maximum address that the
3884 flattened device tree will be copied into upon boot.
3885 For example, if you have a system with 1 GB memory
3886 at physical address 0x10000000, while Linux kernel
3887 only recognizes the first 704 MB as low memory, you
3888 may need to set fdt_high as 0x3C000000 to have the
3889 device tree blob be copied to the maximum address
3890 of the 704 MB low memory, so that Linux kernel can
3891 access it during the boot procedure.
3893 If this is set to the special value 0xFFFFFFFF then
3894 the fdt will not be copied at all on boot. For this
3895 to work it must reside in writable memory, have
3896 sufficient padding on the end of it for u-boot to
3897 add the information it needs into it, and the memory
3898 must be accessible by the kernel.
3900 fdtcontroladdr- if set this is the address of the control flattened
3901 device tree used by U-Boot when CONFIG_OF_CONTROL is
3904 i2cfast - (PPC405GP|PPC405EP only)
3905 if set to 'y' configures Linux I2C driver for fast
3906 mode (400kHZ). This environment variable is used in
3907 initialization code. So, for changes to be effective
3908 it must be saved and board must be reset.
3910 initrd_high - restrict positioning of initrd images:
3911 If this variable is not set, initrd images will be
3912 copied to the highest possible address in RAM; this
3913 is usually what you want since it allows for
3914 maximum initrd size. If for some reason you want to
3915 make sure that the initrd image is loaded below the
3916 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3917 variable to a value of "no" or "off" or "0".
3918 Alternatively, you can set it to a maximum upper
3919 address to use (U-Boot will still check that it
3920 does not overwrite the U-Boot stack and data).
3922 For instance, when you have a system with 16 MB
3923 RAM, and want to reserve 4 MB from use by Linux,
3924 you can do this by adding "mem=12M" to the value of
3925 the "bootargs" variable. However, now you must make
3926 sure that the initrd image is placed in the first
3927 12 MB as well - this can be done with
3929 setenv initrd_high 00c00000
3931 If you set initrd_high to 0xFFFFFFFF, this is an
3932 indication to U-Boot that all addresses are legal
3933 for the Linux kernel, including addresses in flash
3934 memory. In this case U-Boot will NOT COPY the
3935 ramdisk at all. This may be useful to reduce the
3936 boot time on your system, but requires that this
3937 feature is supported by your Linux kernel.
3939 ipaddr - IP address; needed for tftpboot command
3941 loadaddr - Default load address for commands like "bootp",
3942 "rarpboot", "tftpboot", "loadb" or "diskboot"
3944 loads_echo - see CONFIG_LOADS_ECHO
3946 serverip - TFTP server IP address; needed for tftpboot command
3948 bootretry - see CONFIG_BOOT_RETRY_TIME
3950 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3952 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3954 ethprime - controls which interface is used first.
3956 ethact - controls which interface is currently active.
3957 For example you can do the following
3959 => setenv ethact FEC
3960 => ping 192.168.0.1 # traffic sent on FEC
3961 => setenv ethact SCC
3962 => ping 10.0.0.1 # traffic sent on SCC
3964 ethrotate - When set to "no" U-Boot does not go through all
3965 available network interfaces.
3966 It just stays at the currently selected interface.
3968 netretry - When set to "no" each network operation will
3969 either succeed or fail without retrying.
3970 When set to "once" the network operation will
3971 fail when all the available network interfaces
3972 are tried once without success.
3973 Useful on scripts which control the retry operation
3976 npe_ucode - set load address for the NPE microcode
3978 tftpsrcport - If this is set, the value is used for TFTP's
3981 tftpdstport - If this is set, the value is used for TFTP's UDP
3982 destination port instead of the Well Know Port 69.
3984 tftpblocksize - Block size to use for TFTP transfers; if not set,
3985 we use the TFTP server's default block size
3987 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3988 seconds, minimum value is 1000 = 1 second). Defines
3989 when a packet is considered to be lost so it has to
3990 be retransmitted. The default is 5000 = 5 seconds.
3991 Lowering this value may make downloads succeed
3992 faster in networks with high packet loss rates or
3993 with unreliable TFTP servers.
3995 vlan - When set to a value < 4095 the traffic over
3996 Ethernet is encapsulated/received over 802.1q
3999 The following image location variables contain the location of images
4000 used in booting. The "Image" column gives the role of the image and is
4001 not an environment variable name. The other columns are environment
4002 variable names. "File Name" gives the name of the file on a TFTP
4003 server, "RAM Address" gives the location in RAM the image will be
4004 loaded to, and "Flash Location" gives the image's address in NOR
4005 flash or offset in NAND flash.
4007 *Note* - these variables don't have to be defined for all boards, some
4008 boards currenlty use other variables for these purposes, and some
4009 boards use these variables for other purposes.
4011 Image File Name RAM Address Flash Location
4012 ----- --------- ----------- --------------
4013 u-boot u-boot u-boot_addr_r u-boot_addr
4014 Linux kernel bootfile kernel_addr_r kernel_addr
4015 device tree blob fdtfile fdt_addr_r fdt_addr
4016 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4018 The following environment variables may be used and automatically
4019 updated by the network boot commands ("bootp" and "rarpboot"),
4020 depending the information provided by your boot server:
4022 bootfile - see above
4023 dnsip - IP address of your Domain Name Server
4024 dnsip2 - IP address of your secondary Domain Name Server
4025 gatewayip - IP address of the Gateway (Router) to use
4026 hostname - Target hostname
4028 netmask - Subnet Mask
4029 rootpath - Pathname of the root filesystem on the NFS server
4030 serverip - see above
4033 There are two special Environment Variables:
4035 serial# - contains hardware identification information such
4036 as type string and/or serial number
4037 ethaddr - Ethernet address
4039 These variables can be set only once (usually during manufacturing of
4040 the board). U-Boot refuses to delete or overwrite these variables
4041 once they have been set once.
4044 Further special Environment Variables:
4046 ver - Contains the U-Boot version string as printed
4047 with the "version" command. This variable is
4048 readonly (see CONFIG_VERSION_VARIABLE).
4051 Please note that changes to some configuration parameters may take
4052 only effect after the next boot (yes, that's just like Windoze :-).
4055 Command Line Parsing:
4056 =====================
4058 There are two different command line parsers available with U-Boot:
4059 the old "simple" one, and the much more powerful "hush" shell:
4061 Old, simple command line parser:
4062 --------------------------------
4064 - supports environment variables (through setenv / saveenv commands)
4065 - several commands on one line, separated by ';'
4066 - variable substitution using "... ${name} ..." syntax
4067 - special characters ('$', ';') can be escaped by prefixing with '\',
4069 setenv bootcmd bootm \${address}
4070 - You can also escape text by enclosing in single apostrophes, for example:
4071 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4076 - similar to Bourne shell, with control structures like
4077 if...then...else...fi, for...do...done; while...do...done,
4078 until...do...done, ...
4079 - supports environment ("global") variables (through setenv / saveenv
4080 commands) and local shell variables (through standard shell syntax
4081 "name=value"); only environment variables can be used with "run"
4087 (1) If a command line (or an environment variable executed by a "run"
4088 command) contains several commands separated by semicolon, and
4089 one of these commands fails, then the remaining commands will be
4092 (2) If you execute several variables with one call to run (i. e.
4093 calling run with a list of variables as arguments), any failing
4094 command will cause "run" to terminate, i. e. the remaining
4095 variables are not executed.
4097 Note for Redundant Ethernet Interfaces:
4098 =======================================
4100 Some boards come with redundant Ethernet interfaces; U-Boot supports
4101 such configurations and is capable of automatic selection of a
4102 "working" interface when needed. MAC assignment works as follows:
4104 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4105 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4106 "eth1addr" (=>eth1), "eth2addr", ...
4108 If the network interface stores some valid MAC address (for instance
4109 in SROM), this is used as default address if there is NO correspon-
4110 ding setting in the environment; if the corresponding environment
4111 variable is set, this overrides the settings in the card; that means:
4113 o If the SROM has a valid MAC address, and there is no address in the
4114 environment, the SROM's address is used.
4116 o If there is no valid address in the SROM, and a definition in the
4117 environment exists, then the value from the environment variable is
4120 o If both the SROM and the environment contain a MAC address, and
4121 both addresses are the same, this MAC address is used.
4123 o If both the SROM and the environment contain a MAC address, and the
4124 addresses differ, the value from the environment is used and a
4127 o If neither SROM nor the environment contain a MAC address, an error
4130 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4131 will be programmed into hardware as part of the initialization process. This
4132 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4133 The naming convention is as follows:
4134 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4139 U-Boot is capable of booting (and performing other auxiliary operations on)
4140 images in two formats:
4142 New uImage format (FIT)
4143 -----------------------
4145 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4146 to Flattened Device Tree). It allows the use of images with multiple
4147 components (several kernels, ramdisks, etc.), with contents protected by
4148 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4154 Old image format is based on binary files which can be basically anything,
4155 preceded by a special header; see the definitions in include/image.h for
4156 details; basically, the header defines the following image properties:
4158 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4159 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4160 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4161 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4163 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4164 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4165 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4166 * Compression Type (uncompressed, gzip, bzip2)
4172 The header is marked by a special Magic Number, and both the header
4173 and the data portions of the image are secured against corruption by
4180 Although U-Boot should support any OS or standalone application
4181 easily, the main focus has always been on Linux during the design of
4184 U-Boot includes many features that so far have been part of some
4185 special "boot loader" code within the Linux kernel. Also, any
4186 "initrd" images to be used are no longer part of one big Linux image;
4187 instead, kernel and "initrd" are separate images. This implementation
4188 serves several purposes:
4190 - the same features can be used for other OS or standalone
4191 applications (for instance: using compressed images to reduce the
4192 Flash memory footprint)
4194 - it becomes much easier to port new Linux kernel versions because
4195 lots of low-level, hardware dependent stuff are done by U-Boot
4197 - the same Linux kernel image can now be used with different "initrd"
4198 images; of course this also means that different kernel images can
4199 be run with the same "initrd". This makes testing easier (you don't
4200 have to build a new "zImage.initrd" Linux image when you just
4201 change a file in your "initrd"). Also, a field-upgrade of the
4202 software is easier now.
4208 Porting Linux to U-Boot based systems:
4209 ---------------------------------------
4211 U-Boot cannot save you from doing all the necessary modifications to
4212 configure the Linux device drivers for use with your target hardware
4213 (no, we don't intend to provide a full virtual machine interface to
4216 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4218 Just make sure your machine specific header file (for instance
4219 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4220 Information structure as we define in include/asm-<arch>/u-boot.h,
4221 and make sure that your definition of IMAP_ADDR uses the same value
4222 as your U-Boot configuration in CONFIG_SYS_IMMR.
4225 Configuring the Linux kernel:
4226 -----------------------------
4228 No specific requirements for U-Boot. Make sure you have some root
4229 device (initial ramdisk, NFS) for your target system.
4232 Building a Linux Image:
4233 -----------------------
4235 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4236 not used. If you use recent kernel source, a new build target
4237 "uImage" will exist which automatically builds an image usable by
4238 U-Boot. Most older kernels also have support for a "pImage" target,
4239 which was introduced for our predecessor project PPCBoot and uses a
4240 100% compatible format.
4249 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4250 encapsulate a compressed Linux kernel image with header information,
4251 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4253 * build a standard "vmlinux" kernel image (in ELF binary format):
4255 * convert the kernel into a raw binary image:
4257 ${CROSS_COMPILE}-objcopy -O binary \
4258 -R .note -R .comment \
4259 -S vmlinux linux.bin
4261 * compress the binary image:
4265 * package compressed binary image for U-Boot:
4267 mkimage -A ppc -O linux -T kernel -C gzip \
4268 -a 0 -e 0 -n "Linux Kernel Image" \
4269 -d linux.bin.gz uImage
4272 The "mkimage" tool can also be used to create ramdisk images for use
4273 with U-Boot, either separated from the Linux kernel image, or
4274 combined into one file. "mkimage" encapsulates the images with a 64
4275 byte header containing information about target architecture,
4276 operating system, image type, compression method, entry points, time
4277 stamp, CRC32 checksums, etc.
4279 "mkimage" can be called in two ways: to verify existing images and
4280 print the header information, or to build new images.
4282 In the first form (with "-l" option) mkimage lists the information
4283 contained in the header of an existing U-Boot image; this includes
4284 checksum verification:
4286 tools/mkimage -l image
4287 -l ==> list image header information
4289 The second form (with "-d" option) is used to build a U-Boot image
4290 from a "data file" which is used as image payload:
4292 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4293 -n name -d data_file image
4294 -A ==> set architecture to 'arch'
4295 -O ==> set operating system to 'os'
4296 -T ==> set image type to 'type'
4297 -C ==> set compression type 'comp'
4298 -a ==> set load address to 'addr' (hex)
4299 -e ==> set entry point to 'ep' (hex)
4300 -n ==> set image name to 'name'
4301 -d ==> use image data from 'datafile'
4303 Right now, all Linux kernels for PowerPC systems use the same load
4304 address (0x00000000), but the entry point address depends on the
4307 - 2.2.x kernels have the entry point at 0x0000000C,
4308 - 2.3.x and later kernels have the entry point at 0x00000000.
4310 So a typical call to build a U-Boot image would read:
4312 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4313 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4314 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4315 > examples/uImage.TQM850L
4316 Image Name: 2.4.4 kernel for TQM850L
4317 Created: Wed Jul 19 02:34:59 2000
4318 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4319 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4320 Load Address: 0x00000000
4321 Entry Point: 0x00000000
4323 To verify the contents of the image (or check for corruption):
4325 -> tools/mkimage -l examples/uImage.TQM850L
4326 Image Name: 2.4.4 kernel for TQM850L
4327 Created: Wed Jul 19 02:34:59 2000
4328 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4329 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4330 Load Address: 0x00000000
4331 Entry Point: 0x00000000
4333 NOTE: for embedded systems where boot time is critical you can trade
4334 speed for memory and install an UNCOMPRESSED image instead: this
4335 needs more space in Flash, but boots much faster since it does not
4336 need to be uncompressed:
4338 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4339 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4340 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4341 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4342 > examples/uImage.TQM850L-uncompressed
4343 Image Name: 2.4.4 kernel for TQM850L
4344 Created: Wed Jul 19 02:34:59 2000
4345 Image Type: PowerPC Linux Kernel Image (uncompressed)
4346 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4347 Load Address: 0x00000000
4348 Entry Point: 0x00000000
4351 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4352 when your kernel is intended to use an initial ramdisk:
4354 -> tools/mkimage -n 'Simple Ramdisk Image' \
4355 > -A ppc -O linux -T ramdisk -C gzip \
4356 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4357 Image Name: Simple Ramdisk Image
4358 Created: Wed Jan 12 14:01:50 2000
4359 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4360 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4361 Load Address: 0x00000000
4362 Entry Point: 0x00000000
4365 Installing a Linux Image:
4366 -------------------------
4368 To downloading a U-Boot image over the serial (console) interface,
4369 you must convert the image to S-Record format:
4371 objcopy -I binary -O srec examples/image examples/image.srec
4373 The 'objcopy' does not understand the information in the U-Boot
4374 image header, so the resulting S-Record file will be relative to
4375 address 0x00000000. To load it to a given address, you need to
4376 specify the target address as 'offset' parameter with the 'loads'
4379 Example: install the image to address 0x40100000 (which on the
4380 TQM8xxL is in the first Flash bank):
4382 => erase 40100000 401FFFFF
4388 ## Ready for S-Record download ...
4389 ~>examples/image.srec
4390 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4392 15989 15990 15991 15992
4393 [file transfer complete]
4395 ## Start Addr = 0x00000000
4398 You can check the success of the download using the 'iminfo' command;
4399 this includes a checksum verification so you can be sure no data
4400 corruption happened:
4404 ## Checking Image at 40100000 ...
4405 Image Name: 2.2.13 for initrd on TQM850L
4406 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4407 Data Size: 335725 Bytes = 327 kB = 0 MB
4408 Load Address: 00000000
4409 Entry Point: 0000000c
4410 Verifying Checksum ... OK
4416 The "bootm" command is used to boot an application that is stored in
4417 memory (RAM or Flash). In case of a Linux kernel image, the contents
4418 of the "bootargs" environment variable is passed to the kernel as
4419 parameters. You can check and modify this variable using the
4420 "printenv" and "setenv" commands:
4423 => printenv bootargs
4424 bootargs=root=/dev/ram
4426 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4428 => printenv bootargs
4429 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4432 ## Booting Linux kernel at 40020000 ...
4433 Image Name: 2.2.13 for NFS on TQM850L
4434 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4435 Data Size: 381681 Bytes = 372 kB = 0 MB
4436 Load Address: 00000000
4437 Entry Point: 0000000c
4438 Verifying Checksum ... OK
4439 Uncompressing Kernel Image ... OK
4440 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
4441 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4442 time_init: decrementer frequency = 187500000/60
4443 Calibrating delay loop... 49.77 BogoMIPS
4444 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4447 If you want to boot a Linux kernel with initial RAM disk, you pass
4448 the memory addresses of both the kernel and the initrd image (PPBCOOT
4449 format!) to the "bootm" command:
4451 => imi 40100000 40200000
4453 ## Checking Image at 40100000 ...
4454 Image Name: 2.2.13 for initrd on TQM850L
4455 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4456 Data Size: 335725 Bytes = 327 kB = 0 MB
4457 Load Address: 00000000
4458 Entry Point: 0000000c
4459 Verifying Checksum ... OK
4461 ## Checking Image at 40200000 ...
4462 Image Name: Simple Ramdisk Image
4463 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4464 Data Size: 566530 Bytes = 553 kB = 0 MB
4465 Load Address: 00000000
4466 Entry Point: 00000000
4467 Verifying Checksum ... OK
4469 => bootm 40100000 40200000
4470 ## Booting Linux kernel at 40100000 ...
4471 Image Name: 2.2.13 for initrd on TQM850L
4472 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4473 Data Size: 335725 Bytes = 327 kB = 0 MB
4474 Load Address: 00000000
4475 Entry Point: 0000000c
4476 Verifying Checksum ... OK
4477 Uncompressing Kernel Image ... OK
4478 ## Loading RAMDisk Image at 40200000 ...
4479 Image Name: Simple Ramdisk Image
4480 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4481 Data Size: 566530 Bytes = 553 kB = 0 MB
4482 Load Address: 00000000
4483 Entry Point: 00000000
4484 Verifying Checksum ... OK
4485 Loading Ramdisk ... OK
4486 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
4487 Boot arguments: root=/dev/ram
4488 time_init: decrementer frequency = 187500000/60
4489 Calibrating delay loop... 49.77 BogoMIPS
4491 RAMDISK: Compressed image found at block 0
4492 VFS: Mounted root (ext2 filesystem).
4496 Boot Linux and pass a flat device tree:
4499 First, U-Boot must be compiled with the appropriate defines. See the section
4500 titled "Linux Kernel Interface" above for a more in depth explanation. The
4501 following is an example of how to start a kernel and pass an updated
4507 oft=oftrees/mpc8540ads.dtb
4508 => tftp $oftaddr $oft
4509 Speed: 1000, full duplex
4511 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4512 Filename 'oftrees/mpc8540ads.dtb'.
4513 Load address: 0x300000
4516 Bytes transferred = 4106 (100a hex)
4517 => tftp $loadaddr $bootfile
4518 Speed: 1000, full duplex
4520 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4522 Load address: 0x200000
4523 Loading:############
4525 Bytes transferred = 1029407 (fb51f hex)
4530 => bootm $loadaddr - $oftaddr
4531 ## Booting image at 00200000 ...
4532 Image Name: Linux-2.6.17-dirty
4533 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4534 Data Size: 1029343 Bytes = 1005.2 kB
4535 Load Address: 00000000
4536 Entry Point: 00000000
4537 Verifying Checksum ... OK
4538 Uncompressing Kernel Image ... OK
4539 Booting using flat device tree at 0x300000
4540 Using MPC85xx ADS machine description
4541 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4545 More About U-Boot Image Types:
4546 ------------------------------
4548 U-Boot supports the following image types:
4550 "Standalone Programs" are directly runnable in the environment
4551 provided by U-Boot; it is expected that (if they behave
4552 well) you can continue to work in U-Boot after return from
4553 the Standalone Program.
4554 "OS Kernel Images" are usually images of some Embedded OS which
4555 will take over control completely. Usually these programs
4556 will install their own set of exception handlers, device
4557 drivers, set up the MMU, etc. - this means, that you cannot
4558 expect to re-enter U-Boot except by resetting the CPU.
4559 "RAMDisk Images" are more or less just data blocks, and their
4560 parameters (address, size) are passed to an OS kernel that is
4562 "Multi-File Images" contain several images, typically an OS
4563 (Linux) kernel image and one or more data images like
4564 RAMDisks. This construct is useful for instance when you want
4565 to boot over the network using BOOTP etc., where the boot
4566 server provides just a single image file, but you want to get
4567 for instance an OS kernel and a RAMDisk image.
4569 "Multi-File Images" start with a list of image sizes, each
4570 image size (in bytes) specified by an "uint32_t" in network
4571 byte order. This list is terminated by an "(uint32_t)0".
4572 Immediately after the terminating 0 follow the images, one by
4573 one, all aligned on "uint32_t" boundaries (size rounded up to
4574 a multiple of 4 bytes).
4576 "Firmware Images" are binary images containing firmware (like
4577 U-Boot or FPGA images) which usually will be programmed to
4580 "Script files" are command sequences that will be executed by
4581 U-Boot's command interpreter; this feature is especially
4582 useful when you configure U-Boot to use a real shell (hush)
4583 as command interpreter.
4585 Booting the Linux zImage:
4586 -------------------------
4588 On some platforms, it's possible to boot Linux zImage. This is done
4589 using the "bootz" command. The syntax of "bootz" command is the same
4590 as the syntax of "bootm" command.
4592 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4593 kernel with raw initrd images. The syntax is slightly different, the
4594 address of the initrd must be augmented by it's size, in the following
4595 format: "<initrd addres>:<initrd size>".
4601 One of the features of U-Boot is that you can dynamically load and
4602 run "standalone" applications, which can use some resources of
4603 U-Boot like console I/O functions or interrupt services.
4605 Two simple examples are included with the sources:
4610 'examples/hello_world.c' contains a small "Hello World" Demo
4611 application; it is automatically compiled when you build U-Boot.
4612 It's configured to run at address 0x00040004, so you can play with it
4616 ## Ready for S-Record download ...
4617 ~>examples/hello_world.srec
4618 1 2 3 4 5 6 7 8 9 10 11 ...
4619 [file transfer complete]
4621 ## Start Addr = 0x00040004
4623 => go 40004 Hello World! This is a test.
4624 ## Starting application at 0x00040004 ...
4635 Hit any key to exit ...
4637 ## Application terminated, rc = 0x0
4639 Another example, which demonstrates how to register a CPM interrupt
4640 handler with the U-Boot code, can be found in 'examples/timer.c'.
4641 Here, a CPM timer is set up to generate an interrupt every second.
4642 The interrupt service routine is trivial, just printing a '.'
4643 character, but this is just a demo program. The application can be
4644 controlled by the following keys:
4646 ? - print current values og the CPM Timer registers
4647 b - enable interrupts and start timer
4648 e - stop timer and disable interrupts
4649 q - quit application
4652 ## Ready for S-Record download ...
4653 ~>examples/timer.srec
4654 1 2 3 4 5 6 7 8 9 10 11 ...
4655 [file transfer complete]
4657 ## Start Addr = 0x00040004
4660 ## Starting application at 0x00040004 ...
4663 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4666 [q, b, e, ?] Set interval 1000000 us
4669 [q, b, e, ?] ........
4670 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4673 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4676 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4679 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4681 [q, b, e, ?] ...Stopping timer
4683 [q, b, e, ?] ## Application terminated, rc = 0x0
4689 Over time, many people have reported problems when trying to use the
4690 "minicom" terminal emulation program for serial download. I (wd)
4691 consider minicom to be broken, and recommend not to use it. Under
4692 Unix, I recommend to use C-Kermit for general purpose use (and
4693 especially for kermit binary protocol download ("loadb" command), and
4694 use "cu" for S-Record download ("loads" command). See
4695 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4696 for help with kermit.
4699 Nevertheless, if you absolutely want to use it try adding this
4700 configuration to your "File transfer protocols" section:
4702 Name Program Name U/D FullScr IO-Red. Multi
4703 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4704 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4710 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4711 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4713 Building requires a cross environment; it is known to work on
4714 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4715 need gmake since the Makefiles are not compatible with BSD make).
4716 Note that the cross-powerpc package does not install include files;
4717 attempting to build U-Boot will fail because <machine/ansi.h> is
4718 missing. This file has to be installed and patched manually:
4720 # cd /usr/pkg/cross/powerpc-netbsd/include
4722 # ln -s powerpc machine
4723 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4724 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4726 Native builds *don't* work due to incompatibilities between native
4727 and U-Boot include files.
4729 Booting assumes that (the first part of) the image booted is a
4730 stage-2 loader which in turn loads and then invokes the kernel
4731 proper. Loader sources will eventually appear in the NetBSD source
4732 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4733 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4736 Implementation Internals:
4737 =========================
4739 The following is not intended to be a complete description of every
4740 implementation detail. However, it should help to understand the
4741 inner workings of U-Boot and make it easier to port it to custom
4745 Initial Stack, Global Data:
4746 ---------------------------
4748 The implementation of U-Boot is complicated by the fact that U-Boot
4749 starts running out of ROM (flash memory), usually without access to
4750 system RAM (because the memory controller is not initialized yet).
4751 This means that we don't have writable Data or BSS segments, and BSS
4752 is not initialized as zero. To be able to get a C environment working
4753 at all, we have to allocate at least a minimal stack. Implementation
4754 options for this are defined and restricted by the CPU used: Some CPU
4755 models provide on-chip memory (like the IMMR area on MPC8xx and
4756 MPC826x processors), on others (parts of) the data cache can be
4757 locked as (mis-) used as memory, etc.
4759 Chris Hallinan posted a good summary of these issues to the
4760 U-Boot mailing list:
4762 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4763 From: "Chris Hallinan" <clh@net1plus.com>
4764 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4767 Correct me if I'm wrong, folks, but the way I understand it
4768 is this: Using DCACHE as initial RAM for Stack, etc, does not
4769 require any physical RAM backing up the cache. The cleverness
4770 is that the cache is being used as a temporary supply of
4771 necessary storage before the SDRAM controller is setup. It's
4772 beyond the scope of this list to explain the details, but you
4773 can see how this works by studying the cache architecture and
4774 operation in the architecture and processor-specific manuals.
4776 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4777 is another option for the system designer to use as an
4778 initial stack/RAM area prior to SDRAM being available. Either
4779 option should work for you. Using CS 4 should be fine if your
4780 board designers haven't used it for something that would
4781 cause you grief during the initial boot! It is frequently not
4784 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4785 with your processor/board/system design. The default value
4786 you will find in any recent u-boot distribution in
4787 walnut.h should work for you. I'd set it to a value larger
4788 than your SDRAM module. If you have a 64MB SDRAM module, set
4789 it above 400_0000. Just make sure your board has no resources
4790 that are supposed to respond to that address! That code in
4791 start.S has been around a while and should work as is when
4792 you get the config right.
4797 It is essential to remember this, since it has some impact on the C
4798 code for the initialization procedures:
4800 * Initialized global data (data segment) is read-only. Do not attempt
4803 * Do not use any uninitialized global data (or implicitely initialized
4804 as zero data - BSS segment) at all - this is undefined, initiali-
4805 zation is performed later (when relocating to RAM).
4807 * Stack space is very limited. Avoid big data buffers or things like
4810 Having only the stack as writable memory limits means we cannot use
4811 normal global data to share information beween the code. But it
4812 turned out that the implementation of U-Boot can be greatly
4813 simplified by making a global data structure (gd_t) available to all
4814 functions. We could pass a pointer to this data as argument to _all_
4815 functions, but this would bloat the code. Instead we use a feature of
4816 the GCC compiler (Global Register Variables) to share the data: we
4817 place a pointer (gd) to the global data into a register which we
4818 reserve for this purpose.
4820 When choosing a register for such a purpose we are restricted by the
4821 relevant (E)ABI specifications for the current architecture, and by
4822 GCC's implementation.
4824 For PowerPC, the following registers have specific use:
4826 R2: reserved for system use
4827 R3-R4: parameter passing and return values
4828 R5-R10: parameter passing
4829 R13: small data area pointer
4833 (U-Boot also uses R12 as internal GOT pointer. r12
4834 is a volatile register so r12 needs to be reset when
4835 going back and forth between asm and C)
4837 ==> U-Boot will use R2 to hold a pointer to the global data
4839 Note: on PPC, we could use a static initializer (since the
4840 address of the global data structure is known at compile time),
4841 but it turned out that reserving a register results in somewhat
4842 smaller code - although the code savings are not that big (on
4843 average for all boards 752 bytes for the whole U-Boot image,
4844 624 text + 127 data).
4846 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4847 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4849 ==> U-Boot will use P3 to hold a pointer to the global data
4851 On ARM, the following registers are used:
4853 R0: function argument word/integer result
4854 R1-R3: function argument word
4856 R10: stack limit (used only if stack checking if enabled)
4857 R11: argument (frame) pointer
4858 R12: temporary workspace
4861 R15: program counter
4863 ==> U-Boot will use R8 to hold a pointer to the global data
4865 On Nios II, the ABI is documented here:
4866 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4868 ==> U-Boot will use gp to hold a pointer to the global data
4870 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4871 to access small data sections, so gp is free.
4873 On NDS32, the following registers are used:
4875 R0-R1: argument/return
4877 R15: temporary register for assembler
4878 R16: trampoline register
4879 R28: frame pointer (FP)
4880 R29: global pointer (GP)
4881 R30: link register (LP)
4882 R31: stack pointer (SP)
4883 PC: program counter (PC)
4885 ==> U-Boot will use R10 to hold a pointer to the global data
4887 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4888 or current versions of GCC may "optimize" the code too much.
4893 U-Boot runs in system state and uses physical addresses, i.e. the
4894 MMU is not used either for address mapping nor for memory protection.
4896 The available memory is mapped to fixed addresses using the memory
4897 controller. In this process, a contiguous block is formed for each
4898 memory type (Flash, SDRAM, SRAM), even when it consists of several
4899 physical memory banks.
4901 U-Boot is installed in the first 128 kB of the first Flash bank (on
4902 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4903 booting and sizing and initializing DRAM, the code relocates itself
4904 to the upper end of DRAM. Immediately below the U-Boot code some
4905 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4906 configuration setting]. Below that, a structure with global Board
4907 Info data is placed, followed by the stack (growing downward).
4909 Additionally, some exception handler code is copied to the low 8 kB
4910 of DRAM (0x00000000 ... 0x00001FFF).
4912 So a typical memory configuration with 16 MB of DRAM could look like
4915 0x0000 0000 Exception Vector code
4918 0x0000 2000 Free for Application Use
4924 0x00FB FF20 Monitor Stack (Growing downward)
4925 0x00FB FFAC Board Info Data and permanent copy of global data
4926 0x00FC 0000 Malloc Arena
4929 0x00FE 0000 RAM Copy of Monitor Code
4930 ... eventually: LCD or video framebuffer
4931 ... eventually: pRAM (Protected RAM - unchanged by reset)
4932 0x00FF FFFF [End of RAM]
4935 System Initialization:
4936 ----------------------
4938 In the reset configuration, U-Boot starts at the reset entry point
4939 (on most PowerPC systems at address 0x00000100). Because of the reset
4940 configuration for CS0# this is a mirror of the onboard Flash memory.
4941 To be able to re-map memory U-Boot then jumps to its link address.
4942 To be able to implement the initialization code in C, a (small!)
4943 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4944 which provide such a feature like MPC8xx or MPC8260), or in a locked
4945 part of the data cache. After that, U-Boot initializes the CPU core,
4946 the caches and the SIU.
4948 Next, all (potentially) available memory banks are mapped using a
4949 preliminary mapping. For example, we put them on 512 MB boundaries
4950 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4951 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4952 programmed for SDRAM access. Using the temporary configuration, a
4953 simple memory test is run that determines the size of the SDRAM
4956 When there is more than one SDRAM bank, and the banks are of
4957 different size, the largest is mapped first. For equal size, the first
4958 bank (CS2#) is mapped first. The first mapping is always for address
4959 0x00000000, with any additional banks following immediately to create
4960 contiguous memory starting from 0.
4962 Then, the monitor installs itself at the upper end of the SDRAM area
4963 and allocates memory for use by malloc() and for the global Board
4964 Info data; also, the exception vector code is copied to the low RAM
4965 pages, and the final stack is set up.
4967 Only after this relocation will you have a "normal" C environment;
4968 until that you are restricted in several ways, mostly because you are
4969 running from ROM, and because the code will have to be relocated to a
4973 U-Boot Porting Guide:
4974 ----------------------
4976 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4980 int main(int argc, char *argv[])
4982 sighandler_t no_more_time;
4984 signal(SIGALRM, no_more_time);
4985 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4987 if (available_money > available_manpower) {
4988 Pay consultant to port U-Boot;
4992 Download latest U-Boot source;
4994 Subscribe to u-boot mailing list;
4997 email("Hi, I am new to U-Boot, how do I get started?");
5000 Read the README file in the top level directory;
5001 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5002 Read applicable doc/*.README;
5003 Read the source, Luke;
5004 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5007 if (available_money > toLocalCurrency ($2500))
5010 Add a lot of aggravation and time;
5012 if (a similar board exists) { /* hopefully... */
5013 cp -a board/<similar> board/<myboard>
5014 cp include/configs/<similar>.h include/configs/<myboard>.h
5016 Create your own board support subdirectory;
5017 Create your own board include/configs/<myboard>.h file;
5019 Edit new board/<myboard> files
5020 Edit new include/configs/<myboard>.h
5025 Add / modify source code;
5029 email("Hi, I am having problems...");
5031 Send patch file to the U-Boot email list;
5032 if (reasonable critiques)
5033 Incorporate improvements from email list code review;
5035 Defend code as written;
5041 void no_more_time (int sig)
5050 All contributions to U-Boot should conform to the Linux kernel
5051 coding style; see the file "Documentation/CodingStyle" and the script
5052 "scripts/Lindent" in your Linux kernel source directory.
5054 Source files originating from a different project (for example the
5055 MTD subsystem) are generally exempt from these guidelines and are not
5056 reformated to ease subsequent migration to newer versions of those
5059 Please note that U-Boot is implemented in C (and to some small parts in
5060 Assembler); no C++ is used, so please do not use C++ style comments (//)
5063 Please also stick to the following formatting rules:
5064 - remove any trailing white space
5065 - use TAB characters for indentation and vertical alignment, not spaces
5066 - make sure NOT to use DOS '\r\n' line feeds
5067 - do not add more than 2 consecutive empty lines to source files
5068 - do not add trailing empty lines to source files
5070 Submissions which do not conform to the standards may be returned
5071 with a request to reformat the changes.
5077 Since the number of patches for U-Boot is growing, we need to
5078 establish some rules. Submissions which do not conform to these rules
5079 may be rejected, even when they contain important and valuable stuff.
5081 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5083 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5084 see http://lists.denx.de/mailman/listinfo/u-boot
5086 When you send a patch, please include the following information with
5089 * For bug fixes: a description of the bug and how your patch fixes
5090 this bug. Please try to include a way of demonstrating that the
5091 patch actually fixes something.
5093 * For new features: a description of the feature and your
5096 * A CHANGELOG entry as plaintext (separate from the patch)
5098 * For major contributions, your entry to the CREDITS file
5100 * When you add support for a new board, don't forget to add this
5101 board to the MAINTAINERS file, too.
5103 * If your patch adds new configuration options, don't forget to
5104 document these in the README file.
5106 * The patch itself. If you are using git (which is *strongly*
5107 recommended) you can easily generate the patch using the
5108 "git format-patch". If you then use "git send-email" to send it to
5109 the U-Boot mailing list, you will avoid most of the common problems
5110 with some other mail clients.
5112 If you cannot use git, use "diff -purN OLD NEW". If your version of
5113 diff does not support these options, then get the latest version of
5116 The current directory when running this command shall be the parent
5117 directory of the U-Boot source tree (i. e. please make sure that
5118 your patch includes sufficient directory information for the
5121 We prefer patches as plain text. MIME attachments are discouraged,
5122 and compressed attachments must not be used.
5124 * If one logical set of modifications affects or creates several
5125 files, all these changes shall be submitted in a SINGLE patch file.
5127 * Changesets that contain different, unrelated modifications shall be
5128 submitted as SEPARATE patches, one patch per changeset.
5133 * Before sending the patch, run the MAKEALL script on your patched
5134 source tree and make sure that no errors or warnings are reported
5135 for any of the boards.
5137 * Keep your modifications to the necessary minimum: A patch
5138 containing several unrelated changes or arbitrary reformats will be
5139 returned with a request to re-formatting / split it.
5141 * If you modify existing code, make sure that your new code does not
5142 add to the memory footprint of the code ;-) Small is beautiful!
5143 When adding new features, these should compile conditionally only
5144 (using #ifdef), and the resulting code with the new feature
5145 disabled must not need more memory than the old code without your
5148 * Remember that there is a size limit of 100 kB per message on the
5149 u-boot mailing list. Bigger patches will be moderated. If they are
5150 reasonable and not too big, they will be acknowledged. But patches
5151 bigger than the size limit should be avoided.