2 # (C) Copyright 2000 - 2012
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
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 (ARM specific)
862 CONFIG_CMD_TIMER * access to the system tick timer
863 CONFIG_CMD_USB * USB support
864 CONFIG_CMD_CDP * Cisco Discover Protocol support
865 CONFIG_CMD_MFSL * Microblaze FSL support
868 EXAMPLE: If you want all functions except of network
869 support you can write:
871 #include "config_cmd_all.h"
872 #undef CONFIG_CMD_NET
875 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
877 Note: Don't enable the "icache" and "dcache" commands
878 (configuration option CONFIG_CMD_CACHE) unless you know
879 what you (and your U-Boot users) are doing. Data
880 cache cannot be enabled on systems like the 8xx or
881 8260 (where accesses to the IMMR region must be
882 uncached), and it cannot be disabled on all other
883 systems where we (mis-) use the data cache to hold an
884 initial stack and some data.
887 XXX - this list needs to get updated!
891 If this variable is defined, U-Boot will use a device tree
892 to configure its devices, instead of relying on statically
893 compiled #defines in the board file. This option is
894 experimental and only available on a few boards. The device
895 tree is available in the global data as gd->fdt_blob.
897 U-Boot needs to get its device tree from somewhere. This can
898 be done using one of the two options below:
901 If this variable is defined, U-Boot will embed a device tree
902 binary in its image. This device tree file should be in the
903 board directory and called <soc>-<board>.dts. The binary file
904 is then picked up in board_init_f() and made available through
905 the global data structure as gd->blob.
908 If this variable is defined, U-Boot will build a device tree
909 binary. It will be called u-boot.dtb. Architecture-specific
910 code will locate it at run-time. Generally this works by:
912 cat u-boot.bin u-boot.dtb >image.bin
914 and in fact, U-Boot does this for you, creating a file called
915 u-boot-dtb.bin which is useful in the common case. You can
916 still use the individual files if you need something more
921 If this variable is defined, it enables watchdog
922 support for the SoC. There must be support in the SoC
923 specific code for a watchdog. For the 8xx and 8260
924 CPUs, the SIU Watchdog feature is enabled in the SYPCR
925 register. When supported for a specific SoC is
926 available, then no further board specific code should
930 When using a watchdog circuitry external to the used
931 SoC, then define this variable and provide board
932 specific code for the "hw_watchdog_reset" function.
935 CONFIG_VERSION_VARIABLE
936 If this variable is defined, an environment variable
937 named "ver" is created by U-Boot showing the U-Boot
938 version as printed by the "version" command.
939 Any change to this variable will be reverted at the
944 When CONFIG_CMD_DATE is selected, the type of the RTC
945 has to be selected, too. Define exactly one of the
948 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
949 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
950 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
951 CONFIG_RTC_MC146818 - use MC146818 RTC
952 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
953 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
954 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
955 CONFIG_RTC_DS164x - use Dallas DS164x RTC
956 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
957 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
958 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
959 CONFIG_SYS_RV3029_TCR - enable trickle charger on
962 Note that if the RTC uses I2C, then the I2C interface
963 must also be configured. See I2C Support, below.
966 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
967 CONFIG_PCA953X_INFO - enable pca953x info command
969 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
970 chip-ngpio pairs that tell the PCA953X driver the number of
971 pins supported by a particular chip.
973 Note that if the GPIO device uses I2C, then the I2C interface
974 must also be configured. See I2C Support, below.
978 When CONFIG_TIMESTAMP is selected, the timestamp
979 (date and time) of an image is printed by image
980 commands like bootm or iminfo. This option is
981 automatically enabled when you select CONFIG_CMD_DATE .
983 - Partition Labels (disklabels) Supported:
984 Zero or more of the following:
985 CONFIG_MAC_PARTITION Apple's MacOS partition table.
986 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
987 Intel architecture, USB sticks, etc.
988 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
989 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
990 bootloader. Note 2TB partition limit; see
992 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
994 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
995 CONFIG_CMD_SCSI) you must configure support for at
996 least one non-MTD partition type as well.
999 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1000 board configurations files but used nowhere!
1002 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1003 be performed by calling the function
1004 ide_set_reset(int reset)
1005 which has to be defined in a board specific file
1010 Set this to enable ATAPI support.
1015 Set this to enable support for disks larger than 137GB
1016 Also look at CONFIG_SYS_64BIT_LBA.
1017 Whithout these , LBA48 support uses 32bit variables and will 'only'
1018 support disks up to 2.1TB.
1020 CONFIG_SYS_64BIT_LBA:
1021 When enabled, makes the IDE subsystem use 64bit sector addresses.
1025 At the moment only there is only support for the
1026 SYM53C8XX SCSI controller; define
1027 CONFIG_SCSI_SYM53C8XX to enable it.
1029 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1030 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1031 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1032 maximum numbers of LUNs, SCSI ID's and target
1034 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1036 - NETWORK Support (PCI):
1038 Support for Intel 8254x/8257x gigabit chips.
1041 Utility code for direct access to the SPI bus on Intel 8257x.
1042 This does not do anything useful unless you set at least one
1043 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1045 CONFIG_E1000_SPI_GENERIC
1046 Allow generic access to the SPI bus on the Intel 8257x, for
1047 example with the "sspi" command.
1050 Management command for E1000 devices. When used on devices
1051 with SPI support you can reprogram the EEPROM from U-Boot.
1053 CONFIG_E1000_FALLBACK_MAC
1054 default MAC for empty EEPROM after production.
1057 Support for Intel 82557/82559/82559ER chips.
1058 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1059 write routine for first time initialisation.
1062 Support for Digital 2114x chips.
1063 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1064 modem chip initialisation (KS8761/QS6611).
1067 Support for National dp83815 chips.
1070 Support for National dp8382[01] gigabit chips.
1072 - NETWORK Support (other):
1074 CONFIG_DRIVER_AT91EMAC
1075 Support for AT91RM9200 EMAC.
1078 Define this to use reduced MII inteface
1080 CONFIG_DRIVER_AT91EMAC_QUIET
1081 If this defined, the driver is quiet.
1082 The driver doen't show link status messages.
1084 CONFIG_CALXEDA_XGMAC
1085 Support for the Calxeda XGMAC device
1088 Support for SMSC's LAN91C96 chips.
1090 CONFIG_LAN91C96_BASE
1091 Define this to hold the physical address
1092 of the LAN91C96's I/O space
1094 CONFIG_LAN91C96_USE_32_BIT
1095 Define this to enable 32 bit addressing
1098 Support for SMSC's LAN91C111 chip
1100 CONFIG_SMC91111_BASE
1101 Define this to hold the physical address
1102 of the device (I/O space)
1104 CONFIG_SMC_USE_32_BIT
1105 Define this if data bus is 32 bits
1107 CONFIG_SMC_USE_IOFUNCS
1108 Define this to use i/o functions instead of macros
1109 (some hardware wont work with macros)
1111 CONFIG_DRIVER_TI_EMAC
1112 Support for davinci emac
1114 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1115 Define this if you have more then 3 PHYs.
1118 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1120 CONFIG_FTGMAC100_EGIGA
1121 Define this to use GE link update with gigabit PHY.
1122 Define this if FTGMAC100 is connected to gigabit PHY.
1123 If your system has 10/100 PHY only, it might not occur
1124 wrong behavior. Because PHY usually return timeout or
1125 useless data when polling gigabit status and gigabit
1126 control registers. This behavior won't affect the
1127 correctnessof 10/100 link speed update.
1130 Support for SMSC's LAN911x and LAN921x chips
1133 Define this to hold the physical address
1134 of the device (I/O space)
1136 CONFIG_SMC911X_32_BIT
1137 Define this if data bus is 32 bits
1139 CONFIG_SMC911X_16_BIT
1140 Define this if data bus is 16 bits. If your processor
1141 automatically converts one 32 bit word to two 16 bit
1142 words you may also try CONFIG_SMC911X_32_BIT.
1145 Support for Renesas on-chip Ethernet controller
1147 CONFIG_SH_ETHER_USE_PORT
1148 Define the number of ports to be used
1150 CONFIG_SH_ETHER_PHY_ADDR
1151 Define the ETH PHY's address
1153 CONFIG_SH_ETHER_CACHE_WRITEBACK
1154 If this option is set, the driver enables cache flush.
1157 CONFIG_GENERIC_LPC_TPM
1158 Support for generic parallel port TPM devices. Only one device
1159 per system is supported at this time.
1161 CONFIG_TPM_TIS_BASE_ADDRESS
1162 Base address where the generic TPM device is mapped
1163 to. Contemporary x86 systems usually map it at
1167 At the moment only the UHCI host controller is
1168 supported (PIP405, MIP405, MPC5200); define
1169 CONFIG_USB_UHCI to enable it.
1170 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1171 and define CONFIG_USB_STORAGE to enable the USB
1174 Supported are USB Keyboards and USB Floppy drives
1176 MPC5200 USB requires additional defines:
1178 for 528 MHz Clock: 0x0001bbbb
1182 for differential drivers: 0x00001000
1183 for single ended drivers: 0x00005000
1184 for differential drivers on PSC3: 0x00000100
1185 for single ended drivers on PSC3: 0x00004100
1186 CONFIG_SYS_USB_EVENT_POLL
1187 May be defined to allow interrupt polling
1188 instead of using asynchronous interrupts
1190 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1191 txfilltuning field in the EHCI controller on reset.
1194 Define the below if you wish to use the USB console.
1195 Once firmware is rebuilt from a serial console issue the
1196 command "setenv stdin usbtty; setenv stdout usbtty" and
1197 attach your USB cable. The Unix command "dmesg" should print
1198 it has found a new device. The environment variable usbtty
1199 can be set to gserial or cdc_acm to enable your device to
1200 appear to a USB host as a Linux gserial device or a
1201 Common Device Class Abstract Control Model serial device.
1202 If you select usbtty = gserial you should be able to enumerate
1204 # modprobe usbserial vendor=0xVendorID product=0xProductID
1205 else if using cdc_acm, simply setting the environment
1206 variable usbtty to be cdc_acm should suffice. The following
1207 might be defined in YourBoardName.h
1210 Define this to build a UDC device
1213 Define this to have a tty type of device available to
1214 talk to the UDC device
1217 Define this to enable the high speed support for usb
1218 device and usbtty. If this feature is enabled, a routine
1219 int is_usbd_high_speed(void)
1220 also needs to be defined by the driver to dynamically poll
1221 whether the enumeration has succeded at high speed or full
1224 CONFIG_SYS_CONSOLE_IS_IN_ENV
1225 Define this if you want stdin, stdout &/or stderr to
1229 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1230 Derive USB clock from external clock "blah"
1231 - CONFIG_SYS_USB_EXTC_CLK 0x02
1233 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1234 Derive USB clock from brgclk
1235 - CONFIG_SYS_USB_BRG_CLK 0x04
1237 If you have a USB-IF assigned VendorID then you may wish to
1238 define your own vendor specific values either in BoardName.h
1239 or directly in usbd_vendor_info.h. If you don't define
1240 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1241 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1242 should pretend to be a Linux device to it's target host.
1244 CONFIG_USBD_MANUFACTURER
1245 Define this string as the name of your company for
1246 - CONFIG_USBD_MANUFACTURER "my company"
1248 CONFIG_USBD_PRODUCT_NAME
1249 Define this string as the name of your product
1250 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1252 CONFIG_USBD_VENDORID
1253 Define this as your assigned Vendor ID from the USB
1254 Implementors Forum. This *must* be a genuine Vendor ID
1255 to avoid polluting the USB namespace.
1256 - CONFIG_USBD_VENDORID 0xFFFF
1258 CONFIG_USBD_PRODUCTID
1259 Define this as the unique Product ID
1261 - CONFIG_USBD_PRODUCTID 0xFFFF
1263 - ULPI Layer Support:
1264 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1265 the generic ULPI layer. The generic layer accesses the ULPI PHY
1266 via the platform viewport, so you need both the genric layer and
1267 the viewport enabled. Currently only Chipidea/ARC based
1268 viewport is supported.
1269 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1270 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1271 If your ULPI phy needs a different reference clock than the
1272 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1273 the appropriate value in Hz.
1276 The MMC controller on the Intel PXA is supported. To
1277 enable this define CONFIG_MMC. The MMC can be
1278 accessed from the boot prompt by mapping the device
1279 to physical memory similar to flash. Command line is
1280 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1281 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1284 Support for Renesas on-chip MMCIF controller
1286 CONFIG_SH_MMCIF_ADDR
1287 Define the base address of MMCIF registers
1290 Define the clock frequency for MMCIF
1292 - Journaling Flash filesystem support:
1293 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1294 CONFIG_JFFS2_NAND_DEV
1295 Define these for a default partition on a NAND device
1297 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1298 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1299 Define these for a default partition on a NOR device
1301 CONFIG_SYS_JFFS_CUSTOM_PART
1302 Define this to create an own partition. You have to provide a
1303 function struct part_info* jffs2_part_info(int part_num)
1305 If you define only one JFFS2 partition you may also want to
1306 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1307 to disable the command chpart. This is the default when you
1308 have not defined a custom partition
1310 - FAT(File Allocation Table) filesystem write function support:
1313 Define this to enable support for saving memory data as a
1314 file in FAT formatted partition.
1316 This will also enable the command "fatwrite" enabling the
1317 user to write files to FAT.
1319 CBFS (Coreboot Filesystem) support
1322 Define this to enable support for reading from a Coreboot
1323 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1329 Define this to enable standard (PC-Style) keyboard
1333 Standard PC keyboard driver with US (is default) and
1334 GERMAN key layout (switch via environment 'keymap=de') support.
1335 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1336 for cfb_console. Supports cursor blinking.
1341 Define this to enable video support (for output to
1344 CONFIG_VIDEO_CT69000
1346 Enable Chips & Technologies 69000 Video chip
1348 CONFIG_VIDEO_SMI_LYNXEM
1349 Enable Silicon Motion SMI 712/710/810 Video chip. The
1350 video output is selected via environment 'videoout'
1351 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1354 For the CT69000 and SMI_LYNXEM drivers, videomode is
1355 selected via environment 'videomode'. Two different ways
1357 - "videomode=num" 'num' is a standard LiLo mode numbers.
1358 Following standard modes are supported (* is default):
1360 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1361 -------------+---------------------------------------------
1362 8 bits | 0x301* 0x303 0x305 0x161 0x307
1363 15 bits | 0x310 0x313 0x316 0x162 0x319
1364 16 bits | 0x311 0x314 0x317 0x163 0x31A
1365 24 bits | 0x312 0x315 0x318 ? 0x31B
1366 -------------+---------------------------------------------
1367 (i.e. setenv videomode 317; saveenv; reset;)
1369 - "videomode=bootargs" all the video parameters are parsed
1370 from the bootargs. (See drivers/video/videomodes.c)
1373 CONFIG_VIDEO_SED13806
1374 Enable Epson SED13806 driver. This driver supports 8bpp
1375 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1376 or CONFIG_VIDEO_SED13806_16BPP
1379 Enable the Freescale DIU video driver. Reference boards for
1380 SOCs that have a DIU should define this macro to enable DIU
1381 support, and should also define these other macros:
1387 CONFIG_VIDEO_SW_CURSOR
1388 CONFIG_VGA_AS_SINGLE_DEVICE
1390 CONFIG_VIDEO_BMP_LOGO
1392 The DIU driver will look for the 'video-mode' environment
1393 variable, and if defined, enable the DIU as a console during
1394 boot. See the documentation file README.video for a
1395 description of this variable.
1400 Define this to enable a custom keyboard support.
1401 This simply calls drv_keyboard_init() which must be
1402 defined in your board-specific files.
1403 The only board using this so far is RBC823.
1405 - LCD Support: CONFIG_LCD
1407 Define this to enable LCD support (for output to LCD
1408 display); also select one of the supported displays
1409 by defining one of these:
1413 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1415 CONFIG_NEC_NL6448AC33:
1417 NEC NL6448AC33-18. Active, color, single scan.
1419 CONFIG_NEC_NL6448BC20
1421 NEC NL6448BC20-08. 6.5", 640x480.
1422 Active, color, single scan.
1424 CONFIG_NEC_NL6448BC33_54
1426 NEC NL6448BC33-54. 10.4", 640x480.
1427 Active, color, single scan.
1431 Sharp 320x240. Active, color, single scan.
1432 It isn't 16x9, and I am not sure what it is.
1434 CONFIG_SHARP_LQ64D341
1436 Sharp LQ64D341 display, 640x480.
1437 Active, color, single scan.
1441 HLD1045 display, 640x480.
1442 Active, color, single scan.
1446 Optrex CBL50840-2 NF-FW 99 22 M5
1448 Hitachi LMG6912RPFC-00T
1452 320x240. Black & white.
1454 Normally display is black on white background; define
1455 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1457 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1459 If this option is set, the environment is checked for
1460 a variable "splashimage". If found, the usual display
1461 of logo, copyright and system information on the LCD
1462 is suppressed and the BMP image at the address
1463 specified in "splashimage" is loaded instead. The
1464 console is redirected to the "nulldev", too. This
1465 allows for a "silent" boot where a splash screen is
1466 loaded very quickly after power-on.
1468 CONFIG_SPLASH_SCREEN_ALIGN
1470 If this option is set the splash image can be freely positioned
1471 on the screen. Environment variable "splashpos" specifies the
1472 position as "x,y". If a positive number is given it is used as
1473 number of pixel from left/top. If a negative number is given it
1474 is used as number of pixel from right/bottom. You can also
1475 specify 'm' for centering the image.
1478 setenv splashpos m,m
1479 => image at center of screen
1481 setenv splashpos 30,20
1482 => image at x = 30 and y = 20
1484 setenv splashpos -10,m
1485 => vertically centered image
1486 at x = dspWidth - bmpWidth - 9
1488 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1490 If this option is set, additionally to standard BMP
1491 images, gzipped BMP images can be displayed via the
1492 splashscreen support or the bmp command.
1494 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1496 If this option is set, 8-bit RLE compressed BMP images
1497 can be displayed via the splashscreen support or the
1500 - Do compresssing for memory range:
1503 If this option is set, it would use zlib deflate method
1504 to compress the specified memory at its best effort.
1506 - Compression support:
1509 If this option is set, support for bzip2 compressed
1510 images is included. If not, only uncompressed and gzip
1511 compressed images are supported.
1513 NOTE: the bzip2 algorithm requires a lot of RAM, so
1514 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1519 If this option is set, support for lzma compressed
1522 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1523 requires an amount of dynamic memory that is given by the
1526 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1528 Where lc and lp stand for, respectively, Literal context bits
1529 and Literal pos bits.
1531 This value is upper-bounded by 14MB in the worst case. Anyway,
1532 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1533 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1534 a very small buffer.
1536 Use the lzmainfo tool to determinate the lc and lp values and
1537 then calculate the amount of needed dynamic memory (ensuring
1538 the appropriate CONFIG_SYS_MALLOC_LEN value).
1543 The address of PHY on MII bus.
1545 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1547 The clock frequency of the MII bus
1551 If this option is set, support for speed/duplex
1552 detection of gigabit PHY is included.
1554 CONFIG_PHY_RESET_DELAY
1556 Some PHY like Intel LXT971A need extra delay after
1557 reset before any MII register access is possible.
1558 For such PHY, set this option to the usec delay
1559 required. (minimum 300usec for LXT971A)
1561 CONFIG_PHY_CMD_DELAY (ppc4xx)
1563 Some PHY like Intel LXT971A need extra delay after
1564 command issued before MII status register can be read
1574 Define a default value for Ethernet address to use
1575 for the respective Ethernet interface, in case this
1576 is not determined automatically.
1581 Define a default value for the IP address to use for
1582 the default Ethernet interface, in case this is not
1583 determined through e.g. bootp.
1584 (Environment variable "ipaddr")
1586 - Server IP address:
1589 Defines a default value for the IP address of a TFTP
1590 server to contact when using the "tftboot" command.
1591 (Environment variable "serverip")
1593 CONFIG_KEEP_SERVERADDR
1595 Keeps the server's MAC address, in the env 'serveraddr'
1596 for passing to bootargs (like Linux's netconsole option)
1598 - Gateway IP address:
1601 Defines a default value for the IP address of the
1602 default router where packets to other networks are
1604 (Environment variable "gatewayip")
1609 Defines a default value for the subnet mask (or
1610 routing prefix) which is used to determine if an IP
1611 address belongs to the local subnet or needs to be
1612 forwarded through a router.
1613 (Environment variable "netmask")
1615 - Multicast TFTP Mode:
1618 Defines whether you want to support multicast TFTP as per
1619 rfc-2090; for example to work with atftp. Lets lots of targets
1620 tftp down the same boot image concurrently. Note: the Ethernet
1621 driver in use must provide a function: mcast() to join/leave a
1624 - BOOTP Recovery Mode:
1625 CONFIG_BOOTP_RANDOM_DELAY
1627 If you have many targets in a network that try to
1628 boot using BOOTP, you may want to avoid that all
1629 systems send out BOOTP requests at precisely the same
1630 moment (which would happen for instance at recovery
1631 from a power failure, when all systems will try to
1632 boot, thus flooding the BOOTP server. Defining
1633 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1634 inserted before sending out BOOTP requests. The
1635 following delays are inserted then:
1637 1st BOOTP request: delay 0 ... 1 sec
1638 2nd BOOTP request: delay 0 ... 2 sec
1639 3rd BOOTP request: delay 0 ... 4 sec
1641 BOOTP requests: delay 0 ... 8 sec
1643 - DHCP Advanced Options:
1644 You can fine tune the DHCP functionality by defining
1645 CONFIG_BOOTP_* symbols:
1647 CONFIG_BOOTP_SUBNETMASK
1648 CONFIG_BOOTP_GATEWAY
1649 CONFIG_BOOTP_HOSTNAME
1650 CONFIG_BOOTP_NISDOMAIN
1651 CONFIG_BOOTP_BOOTPATH
1652 CONFIG_BOOTP_BOOTFILESIZE
1655 CONFIG_BOOTP_SEND_HOSTNAME
1656 CONFIG_BOOTP_NTPSERVER
1657 CONFIG_BOOTP_TIMEOFFSET
1658 CONFIG_BOOTP_VENDOREX
1659 CONFIG_BOOTP_MAY_FAIL
1661 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1662 environment variable, not the BOOTP server.
1664 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1665 after the configured retry count, the call will fail
1666 instead of starting over. This can be used to fail over
1667 to Link-local IP address configuration if the DHCP server
1670 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1671 serverip from a DHCP server, it is possible that more
1672 than one DNS serverip is offered to the client.
1673 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1674 serverip will be stored in the additional environment
1675 variable "dnsip2". The first DNS serverip is always
1676 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1679 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1680 to do a dynamic update of a DNS server. To do this, they
1681 need the hostname of the DHCP requester.
1682 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1683 of the "hostname" environment variable is passed as
1684 option 12 to the DHCP server.
1686 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1688 A 32bit value in microseconds for a delay between
1689 receiving a "DHCP Offer" and sending the "DHCP Request".
1690 This fixes a problem with certain DHCP servers that don't
1691 respond 100% of the time to a "DHCP request". E.g. On an
1692 AT91RM9200 processor running at 180MHz, this delay needed
1693 to be *at least* 15,000 usec before a Windows Server 2003
1694 DHCP server would reply 100% of the time. I recommend at
1695 least 50,000 usec to be safe. The alternative is to hope
1696 that one of the retries will be successful but note that
1697 the DHCP timeout and retry process takes a longer than
1700 - Link-local IP address negotiation:
1701 Negotiate with other link-local clients on the local network
1702 for an address that doesn't require explicit configuration.
1703 This is especially useful if a DHCP server cannot be guaranteed
1704 to exist in all environments that the device must operate.
1706 See doc/README.link-local for more information.
1709 CONFIG_CDP_DEVICE_ID
1711 The device id used in CDP trigger frames.
1713 CONFIG_CDP_DEVICE_ID_PREFIX
1715 A two character string which is prefixed to the MAC address
1720 A printf format string which contains the ascii name of
1721 the port. Normally is set to "eth%d" which sets
1722 eth0 for the first Ethernet, eth1 for the second etc.
1724 CONFIG_CDP_CAPABILITIES
1726 A 32bit integer which indicates the device capabilities;
1727 0x00000010 for a normal host which does not forwards.
1731 An ascii string containing the version of the software.
1735 An ascii string containing the name of the platform.
1739 A 32bit integer sent on the trigger.
1741 CONFIG_CDP_POWER_CONSUMPTION
1743 A 16bit integer containing the power consumption of the
1744 device in .1 of milliwatts.
1746 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1748 A byte containing the id of the VLAN.
1750 - Status LED: CONFIG_STATUS_LED
1752 Several configurations allow to display the current
1753 status using a LED. For instance, the LED will blink
1754 fast while running U-Boot code, stop blinking as
1755 soon as a reply to a BOOTP request was received, and
1756 start blinking slow once the Linux kernel is running
1757 (supported by a status LED driver in the Linux
1758 kernel). Defining CONFIG_STATUS_LED enables this
1761 - CAN Support: CONFIG_CAN_DRIVER
1763 Defining CONFIG_CAN_DRIVER enables CAN driver support
1764 on those systems that support this (optional)
1765 feature, like the TQM8xxL modules.
1767 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1769 These enable I2C serial bus commands. Defining either of
1770 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1771 include the appropriate I2C driver for the selected CPU.
1773 This will allow you to use i2c commands at the u-boot
1774 command line (as long as you set CONFIG_CMD_I2C in
1775 CONFIG_COMMANDS) and communicate with i2c based realtime
1776 clock chips. See common/cmd_i2c.c for a description of the
1777 command line interface.
1779 CONFIG_HARD_I2C selects a hardware I2C controller.
1781 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1782 bit-banging) driver instead of CPM or similar hardware
1785 There are several other quantities that must also be
1786 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1788 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1789 to be the frequency (in Hz) at which you wish your i2c bus
1790 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1791 the CPU's i2c node address).
1793 Now, the u-boot i2c code for the mpc8xx
1794 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1795 and so its address should therefore be cleared to 0 (See,
1796 eg, MPC823e User's Manual p.16-473). So, set
1797 CONFIG_SYS_I2C_SLAVE to 0.
1799 CONFIG_SYS_I2C_INIT_MPC5XXX
1801 When a board is reset during an i2c bus transfer
1802 chips might think that the current transfer is still
1803 in progress. Reset the slave devices by sending start
1804 commands until the slave device responds.
1806 That's all that's required for CONFIG_HARD_I2C.
1808 If you use the software i2c interface (CONFIG_SOFT_I2C)
1809 then the following macros need to be defined (examples are
1810 from include/configs/lwmon.h):
1814 (Optional). Any commands necessary to enable the I2C
1815 controller or configure ports.
1817 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1821 (Only for MPC8260 CPU). The I/O port to use (the code
1822 assumes both bits are on the same port). Valid values
1823 are 0..3 for ports A..D.
1827 The code necessary to make the I2C data line active
1828 (driven). If the data line is open collector, this
1831 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1835 The code necessary to make the I2C data line tri-stated
1836 (inactive). If the data line is open collector, this
1839 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1843 Code that returns TRUE if the I2C data line is high,
1846 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1850 If <bit> is TRUE, sets the I2C data line high. If it
1851 is FALSE, it clears it (low).
1853 eg: #define I2C_SDA(bit) \
1854 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1855 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1859 If <bit> is TRUE, sets the I2C clock line high. If it
1860 is FALSE, it clears it (low).
1862 eg: #define I2C_SCL(bit) \
1863 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1864 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1868 This delay is invoked four times per clock cycle so this
1869 controls the rate of data transfer. The data rate thus
1870 is 1 / (I2C_DELAY * 4). Often defined to be something
1873 #define I2C_DELAY udelay(2)
1875 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1877 If your arch supports the generic GPIO framework (asm/gpio.h),
1878 then you may alternatively define the two GPIOs that are to be
1879 used as SCL / SDA. Any of the previous I2C_xxx macros will
1880 have GPIO-based defaults assigned to them as appropriate.
1882 You should define these to the GPIO value as given directly to
1883 the generic GPIO functions.
1885 CONFIG_SYS_I2C_INIT_BOARD
1887 When a board is reset during an i2c bus transfer
1888 chips might think that the current transfer is still
1889 in progress. On some boards it is possible to access
1890 the i2c SCLK line directly, either by using the
1891 processor pin as a GPIO or by having a second pin
1892 connected to the bus. If this option is defined a
1893 custom i2c_init_board() routine in boards/xxx/board.c
1894 is run early in the boot sequence.
1896 CONFIG_SYS_I2C_BOARD_LATE_INIT
1898 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1899 defined a custom i2c_board_late_init() routine in
1900 boards/xxx/board.c is run AFTER the operations in i2c_init()
1901 is completed. This callpoint can be used to unreset i2c bus
1902 using CPU i2c controller register accesses for CPUs whose i2c
1903 controller provide such a method. It is called at the end of
1904 i2c_init() to allow i2c_init operations to setup the i2c bus
1905 controller on the CPU (e.g. setting bus speed & slave address).
1907 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1909 This option enables configuration of bi_iic_fast[] flags
1910 in u-boot bd_info structure based on u-boot environment
1911 variable "i2cfast". (see also i2cfast)
1913 CONFIG_I2C_MULTI_BUS
1915 This option allows the use of multiple I2C buses, each of which
1916 must have a controller. At any point in time, only one bus is
1917 active. To switch to a different bus, use the 'i2c dev' command.
1918 Note that bus numbering is zero-based.
1920 CONFIG_SYS_I2C_NOPROBES
1922 This option specifies a list of I2C devices that will be skipped
1923 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1924 is set, specify a list of bus-device pairs. Otherwise, specify
1925 a 1D array of device addresses
1928 #undef CONFIG_I2C_MULTI_BUS
1929 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1931 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1933 #define CONFIG_I2C_MULTI_BUS
1934 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1936 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1938 CONFIG_SYS_SPD_BUS_NUM
1940 If defined, then this indicates the I2C bus number for DDR SPD.
1941 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1943 CONFIG_SYS_RTC_BUS_NUM
1945 If defined, then this indicates the I2C bus number for the RTC.
1946 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1948 CONFIG_SYS_DTT_BUS_NUM
1950 If defined, then this indicates the I2C bus number for the DTT.
1951 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1953 CONFIG_SYS_I2C_DTT_ADDR:
1955 If defined, specifies the I2C address of the DTT device.
1956 If not defined, then U-Boot uses predefined value for
1957 specified DTT device.
1961 Define this option if you want to use Freescale's I2C driver in
1962 drivers/i2c/fsl_i2c.c.
1966 Define this option if you have I2C devices reached over 1 .. n
1967 I2C Muxes like the pca9544a. This option addes a new I2C
1968 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1969 new I2C Bus to the existing I2C Busses. If you select the
1970 new Bus with "i2c dev", u-bbot sends first the commandos for
1971 the muxes to activate this new "bus".
1973 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1977 Adding a new I2C Bus reached over 2 pca9544a muxes
1978 The First mux with address 70 and channel 6
1979 The Second mux with address 71 and channel 4
1981 => i2c bus pca9544a:70:6:pca9544a:71:4
1983 Use the "i2c bus" command without parameter, to get a list
1984 of I2C Busses with muxes:
1987 Busses reached over muxes:
1989 reached over Mux(es):
1992 reached over Mux(es):
1997 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1998 u-boot first sends the command to the mux@70 to enable
1999 channel 6, and then the command to the mux@71 to enable
2002 After that, you can use the "normal" i2c commands as
2003 usual to communicate with your I2C devices behind
2006 This option is actually implemented for the bitbanging
2007 algorithm in common/soft_i2c.c and for the Hardware I2C
2008 Bus on the MPC8260. But it should be not so difficult
2009 to add this option to other architectures.
2011 CONFIG_SOFT_I2C_READ_REPEATED_START
2013 defining this will force the i2c_read() function in
2014 the soft_i2c driver to perform an I2C repeated start
2015 between writing the address pointer and reading the
2016 data. If this define is omitted the default behaviour
2017 of doing a stop-start sequence will be used. Most I2C
2018 devices can use either method, but some require one or
2021 - SPI Support: CONFIG_SPI
2023 Enables SPI driver (so far only tested with
2024 SPI EEPROM, also an instance works with Crystal A/D and
2025 D/As on the SACSng board)
2029 Enables the driver for SPI controller on SuperH. Currently
2030 only SH7757 is supported.
2034 Enables extended (16-bit) SPI EEPROM addressing.
2035 (symmetrical to CONFIG_I2C_X)
2039 Enables a software (bit-bang) SPI driver rather than
2040 using hardware support. This is a general purpose
2041 driver that only requires three general I/O port pins
2042 (two outputs, one input) to function. If this is
2043 defined, the board configuration must define several
2044 SPI configuration items (port pins to use, etc). For
2045 an example, see include/configs/sacsng.h.
2049 Enables a hardware SPI driver for general-purpose reads
2050 and writes. As with CONFIG_SOFT_SPI, the board configuration
2051 must define a list of chip-select function pointers.
2052 Currently supported on some MPC8xxx processors. For an
2053 example, see include/configs/mpc8349emds.h.
2057 Enables the driver for the SPI controllers on i.MX and MXC
2058 SoCs. Currently i.MX31/35/51 are supported.
2060 - FPGA Support: CONFIG_FPGA
2062 Enables FPGA subsystem.
2064 CONFIG_FPGA_<vendor>
2066 Enables support for specific chip vendors.
2069 CONFIG_FPGA_<family>
2071 Enables support for FPGA family.
2072 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2076 Specify the number of FPGA devices to support.
2078 CONFIG_SYS_FPGA_PROG_FEEDBACK
2080 Enable printing of hash marks during FPGA configuration.
2082 CONFIG_SYS_FPGA_CHECK_BUSY
2084 Enable checks on FPGA configuration interface busy
2085 status by the configuration function. This option
2086 will require a board or device specific function to
2091 If defined, a function that provides delays in the FPGA
2092 configuration driver.
2094 CONFIG_SYS_FPGA_CHECK_CTRLC
2095 Allow Control-C to interrupt FPGA configuration
2097 CONFIG_SYS_FPGA_CHECK_ERROR
2099 Check for configuration errors during FPGA bitfile
2100 loading. For example, abort during Virtex II
2101 configuration if the INIT_B line goes low (which
2102 indicated a CRC error).
2104 CONFIG_SYS_FPGA_WAIT_INIT
2106 Maximum time to wait for the INIT_B line to deassert
2107 after PROB_B has been deasserted during a Virtex II
2108 FPGA configuration sequence. The default time is 500
2111 CONFIG_SYS_FPGA_WAIT_BUSY
2113 Maximum time to wait for BUSY to deassert during
2114 Virtex II FPGA configuration. The default is 5 ms.
2116 CONFIG_SYS_FPGA_WAIT_CONFIG
2118 Time to wait after FPGA configuration. The default is
2121 - Configuration Management:
2124 If defined, this string will be added to the U-Boot
2125 version information (U_BOOT_VERSION)
2127 - Vendor Parameter Protection:
2129 U-Boot considers the values of the environment
2130 variables "serial#" (Board Serial Number) and
2131 "ethaddr" (Ethernet Address) to be parameters that
2132 are set once by the board vendor / manufacturer, and
2133 protects these variables from casual modification by
2134 the user. Once set, these variables are read-only,
2135 and write or delete attempts are rejected. You can
2136 change this behaviour:
2138 If CONFIG_ENV_OVERWRITE is #defined in your config
2139 file, the write protection for vendor parameters is
2140 completely disabled. Anybody can change or delete
2143 Alternatively, if you #define _both_ CONFIG_ETHADDR
2144 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2145 Ethernet address is installed in the environment,
2146 which can be changed exactly ONCE by the user. [The
2147 serial# is unaffected by this, i. e. it remains
2153 Define this variable to enable the reservation of
2154 "protected RAM", i. e. RAM which is not overwritten
2155 by U-Boot. Define CONFIG_PRAM to hold the number of
2156 kB you want to reserve for pRAM. You can overwrite
2157 this default value by defining an environment
2158 variable "pram" to the number of kB you want to
2159 reserve. Note that the board info structure will
2160 still show the full amount of RAM. If pRAM is
2161 reserved, a new environment variable "mem" will
2162 automatically be defined to hold the amount of
2163 remaining RAM in a form that can be passed as boot
2164 argument to Linux, for instance like that:
2166 setenv bootargs ... mem=\${mem}
2169 This way you can tell Linux not to use this memory,
2170 either, which results in a memory region that will
2171 not be affected by reboots.
2173 *WARNING* If your board configuration uses automatic
2174 detection of the RAM size, you must make sure that
2175 this memory test is non-destructive. So far, the
2176 following board configurations are known to be
2179 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2180 HERMES, IP860, RPXlite, LWMON, LANTEC,
2186 Define this variable to stop the system in case of a
2187 fatal error, so that you have to reset it manually.
2188 This is probably NOT a good idea for an embedded
2189 system where you want the system to reboot
2190 automatically as fast as possible, but it may be
2191 useful during development since you can try to debug
2192 the conditions that lead to the situation.
2194 CONFIG_NET_RETRY_COUNT
2196 This variable defines the number of retries for
2197 network operations like ARP, RARP, TFTP, or BOOTP
2198 before giving up the operation. If not defined, a
2199 default value of 5 is used.
2203 Timeout waiting for an ARP reply in milliseconds.
2207 Timeout in milliseconds used in NFS protocol.
2208 If you encounter "ERROR: Cannot umount" in nfs command,
2209 try longer timeout such as
2210 #define CONFIG_NFS_TIMEOUT 10000UL
2212 - Command Interpreter:
2213 CONFIG_AUTO_COMPLETE
2215 Enable auto completion of commands using TAB.
2217 Note that this feature has NOT been implemented yet
2218 for the "hush" shell.
2221 CONFIG_SYS_HUSH_PARSER
2223 Define this variable to enable the "hush" shell (from
2224 Busybox) as command line interpreter, thus enabling
2225 powerful command line syntax like
2226 if...then...else...fi conditionals or `&&' and '||'
2227 constructs ("shell scripts").
2229 If undefined, you get the old, much simpler behaviour
2230 with a somewhat smaller memory footprint.
2233 CONFIG_SYS_PROMPT_HUSH_PS2
2235 This defines the secondary prompt string, which is
2236 printed when the command interpreter needs more input
2237 to complete a command. Usually "> ".
2241 In the current implementation, the local variables
2242 space and global environment variables space are
2243 separated. Local variables are those you define by
2244 simply typing `name=value'. To access a local
2245 variable later on, you have write `$name' or
2246 `${name}'; to execute the contents of a variable
2247 directly type `$name' at the command prompt.
2249 Global environment variables are those you use
2250 setenv/printenv to work with. To run a command stored
2251 in such a variable, you need to use the run command,
2252 and you must not use the '$' sign to access them.
2254 To store commands and special characters in a
2255 variable, please use double quotation marks
2256 surrounding the whole text of the variable, instead
2257 of the backslashes before semicolons and special
2260 - Commandline Editing and History:
2261 CONFIG_CMDLINE_EDITING
2263 Enable editing and History functions for interactive
2264 commandline input operations
2266 - Default Environment:
2267 CONFIG_EXTRA_ENV_SETTINGS
2269 Define this to contain any number of null terminated
2270 strings (variable = value pairs) that will be part of
2271 the default environment compiled into the boot image.
2273 For example, place something like this in your
2274 board's config file:
2276 #define CONFIG_EXTRA_ENV_SETTINGS \
2280 Warning: This method is based on knowledge about the
2281 internal format how the environment is stored by the
2282 U-Boot code. This is NOT an official, exported
2283 interface! Although it is unlikely that this format
2284 will change soon, there is no guarantee either.
2285 You better know what you are doing here.
2287 Note: overly (ab)use of the default environment is
2288 discouraged. Make sure to check other ways to preset
2289 the environment like the "source" command or the
2292 CONFIG_ENV_VARS_UBOOT_CONFIG
2294 Define this in order to add variables describing the
2295 U-Boot build configuration to the default environment.
2296 These will be named arch, cpu, board, vendor, and soc.
2298 Enabling this option will cause the following to be defined:
2306 - DataFlash Support:
2307 CONFIG_HAS_DATAFLASH
2309 Defining this option enables DataFlash features and
2310 allows to read/write in Dataflash via the standard
2313 - Serial Flash support
2316 Defining this option enables SPI flash commands
2317 'sf probe/read/write/erase/update'.
2319 Usage requires an initial 'probe' to define the serial
2320 flash parameters, followed by read/write/erase/update
2323 The following defaults may be provided by the platform
2324 to handle the common case when only a single serial
2325 flash is present on the system.
2327 CONFIG_SF_DEFAULT_BUS Bus identifier
2328 CONFIG_SF_DEFAULT_CS Chip-select
2329 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2330 CONFIG_SF_DEFAULT_SPEED in Hz
2332 - SystemACE Support:
2335 Adding this option adds support for Xilinx SystemACE
2336 chips attached via some sort of local bus. The address
2337 of the chip must also be defined in the
2338 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2340 #define CONFIG_SYSTEMACE
2341 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2343 When SystemACE support is added, the "ace" device type
2344 becomes available to the fat commands, i.e. fatls.
2346 - TFTP Fixed UDP Port:
2349 If this is defined, the environment variable tftpsrcp
2350 is used to supply the TFTP UDP source port value.
2351 If tftpsrcp isn't defined, the normal pseudo-random port
2352 number generator is used.
2354 Also, the environment variable tftpdstp is used to supply
2355 the TFTP UDP destination port value. If tftpdstp isn't
2356 defined, the normal port 69 is used.
2358 The purpose for tftpsrcp is to allow a TFTP server to
2359 blindly start the TFTP transfer using the pre-configured
2360 target IP address and UDP port. This has the effect of
2361 "punching through" the (Windows XP) firewall, allowing
2362 the remainder of the TFTP transfer to proceed normally.
2363 A better solution is to properly configure the firewall,
2364 but sometimes that is not allowed.
2366 - Show boot progress:
2367 CONFIG_SHOW_BOOT_PROGRESS
2369 Defining this option allows to add some board-
2370 specific code (calling a user-provided function
2371 "show_boot_progress(int)") that enables you to show
2372 the system's boot progress on some display (for
2373 example, some LED's) on your board. At the moment,
2374 the following checkpoints are implemented:
2376 - Detailed boot stage timing
2378 Define this option to get detailed timing of each stage
2379 of the boot process.
2381 CONFIG_BOOTSTAGE_USER_COUNT
2382 This is the number of available user bootstage records.
2383 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2384 a new ID will be allocated from this stash. If you exceed
2385 the limit, recording will stop.
2387 CONFIG_BOOTSTAGE_REPORT
2388 Define this to print a report before boot, similar to this:
2390 Timer summary in microseconds:
2393 3,575,678 3,575,678 board_init_f start
2394 3,575,695 17 arch_cpu_init A9
2395 3,575,777 82 arch_cpu_init done
2396 3,659,598 83,821 board_init_r start
2397 3,910,375 250,777 main_loop
2398 29,916,167 26,005,792 bootm_start
2399 30,361,327 445,160 start_kernel
2401 CONFIG_CMD_BOOTSTAGE
2402 Add a 'bootstage' command which supports printing a report
2403 and un/stashing of bootstage data.
2405 CONFIG_BOOTSTAGE_FDT
2406 Stash the bootstage information in the FDT. A root 'bootstage'
2407 node is created with each bootstage id as a child. Each child
2408 has a 'name' property and either 'mark' containing the
2409 mark time in microsecond, or 'accum' containing the
2410 accumulated time for that bootstage id in microseconds.
2415 name = "board_init_f";
2424 Code in the Linux kernel can find this in /proc/devicetree.
2426 Legacy uImage format:
2429 1 common/cmd_bootm.c before attempting to boot an image
2430 -1 common/cmd_bootm.c Image header has bad magic number
2431 2 common/cmd_bootm.c Image header has correct magic number
2432 -2 common/cmd_bootm.c Image header has bad checksum
2433 3 common/cmd_bootm.c Image header has correct checksum
2434 -3 common/cmd_bootm.c Image data has bad checksum
2435 4 common/cmd_bootm.c Image data has correct checksum
2436 -4 common/cmd_bootm.c Image is for unsupported architecture
2437 5 common/cmd_bootm.c Architecture check OK
2438 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2439 6 common/cmd_bootm.c Image Type check OK
2440 -6 common/cmd_bootm.c gunzip uncompression error
2441 -7 common/cmd_bootm.c Unimplemented compression type
2442 7 common/cmd_bootm.c Uncompression OK
2443 8 common/cmd_bootm.c No uncompress/copy overwrite error
2444 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2446 9 common/image.c Start initial ramdisk verification
2447 -10 common/image.c Ramdisk header has bad magic number
2448 -11 common/image.c Ramdisk header has bad checksum
2449 10 common/image.c Ramdisk header is OK
2450 -12 common/image.c Ramdisk data has bad checksum
2451 11 common/image.c Ramdisk data has correct checksum
2452 12 common/image.c Ramdisk verification complete, start loading
2453 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2454 13 common/image.c Start multifile image verification
2455 14 common/image.c No initial ramdisk, no multifile, continue.
2457 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2459 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2460 -31 post/post.c POST test failed, detected by post_output_backlog()
2461 -32 post/post.c POST test failed, detected by post_run_single()
2463 34 common/cmd_doc.c before loading a Image from a DOC device
2464 -35 common/cmd_doc.c Bad usage of "doc" command
2465 35 common/cmd_doc.c correct usage of "doc" command
2466 -36 common/cmd_doc.c No boot device
2467 36 common/cmd_doc.c correct boot device
2468 -37 common/cmd_doc.c Unknown Chip ID on boot device
2469 37 common/cmd_doc.c correct chip ID found, device available
2470 -38 common/cmd_doc.c Read Error on boot device
2471 38 common/cmd_doc.c reading Image header from DOC device OK
2472 -39 common/cmd_doc.c Image header has bad magic number
2473 39 common/cmd_doc.c Image header has correct magic number
2474 -40 common/cmd_doc.c Error reading Image from DOC device
2475 40 common/cmd_doc.c Image header has correct magic number
2476 41 common/cmd_ide.c before loading a Image from a IDE device
2477 -42 common/cmd_ide.c Bad usage of "ide" command
2478 42 common/cmd_ide.c correct usage of "ide" command
2479 -43 common/cmd_ide.c No boot device
2480 43 common/cmd_ide.c boot device found
2481 -44 common/cmd_ide.c Device not available
2482 44 common/cmd_ide.c Device available
2483 -45 common/cmd_ide.c wrong partition selected
2484 45 common/cmd_ide.c partition selected
2485 -46 common/cmd_ide.c Unknown partition table
2486 46 common/cmd_ide.c valid partition table found
2487 -47 common/cmd_ide.c Invalid partition type
2488 47 common/cmd_ide.c correct partition type
2489 -48 common/cmd_ide.c Error reading Image Header on boot device
2490 48 common/cmd_ide.c reading Image Header from IDE device OK
2491 -49 common/cmd_ide.c Image header has bad magic number
2492 49 common/cmd_ide.c Image header has correct magic number
2493 -50 common/cmd_ide.c Image header has bad checksum
2494 50 common/cmd_ide.c Image header has correct checksum
2495 -51 common/cmd_ide.c Error reading Image from IDE device
2496 51 common/cmd_ide.c reading Image from IDE device OK
2497 52 common/cmd_nand.c before loading a Image from a NAND device
2498 -53 common/cmd_nand.c Bad usage of "nand" command
2499 53 common/cmd_nand.c correct usage of "nand" command
2500 -54 common/cmd_nand.c No boot device
2501 54 common/cmd_nand.c boot device found
2502 -55 common/cmd_nand.c Unknown Chip ID on boot device
2503 55 common/cmd_nand.c correct chip ID found, device available
2504 -56 common/cmd_nand.c Error reading Image Header on boot device
2505 56 common/cmd_nand.c reading Image Header from NAND device OK
2506 -57 common/cmd_nand.c Image header has bad magic number
2507 57 common/cmd_nand.c Image header has correct magic number
2508 -58 common/cmd_nand.c Error reading Image from NAND device
2509 58 common/cmd_nand.c reading Image from NAND device OK
2511 -60 common/env_common.c Environment has a bad CRC, using default
2513 64 net/eth.c starting with Ethernet configuration.
2514 -64 net/eth.c no Ethernet found.
2515 65 net/eth.c Ethernet found.
2517 -80 common/cmd_net.c usage wrong
2518 80 common/cmd_net.c before calling NetLoop()
2519 -81 common/cmd_net.c some error in NetLoop() occurred
2520 81 common/cmd_net.c NetLoop() back without error
2521 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2522 82 common/cmd_net.c trying automatic boot
2523 83 common/cmd_net.c running "source" command
2524 -83 common/cmd_net.c some error in automatic boot or "source" command
2525 84 common/cmd_net.c end without errors
2530 100 common/cmd_bootm.c Kernel FIT Image has correct format
2531 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2532 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2533 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2534 102 common/cmd_bootm.c Kernel unit name specified
2535 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2536 103 common/cmd_bootm.c Found configuration node
2537 104 common/cmd_bootm.c Got kernel subimage node offset
2538 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2539 105 common/cmd_bootm.c Kernel subimage hash verification OK
2540 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2541 106 common/cmd_bootm.c Architecture check OK
2542 -106 common/cmd_bootm.c Kernel subimage has wrong type
2543 107 common/cmd_bootm.c Kernel subimage type OK
2544 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2545 108 common/cmd_bootm.c Got kernel subimage data/size
2546 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2547 -109 common/cmd_bootm.c Can't get kernel subimage type
2548 -110 common/cmd_bootm.c Can't get kernel subimage comp
2549 -111 common/cmd_bootm.c Can't get kernel subimage os
2550 -112 common/cmd_bootm.c Can't get kernel subimage load address
2551 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2553 120 common/image.c Start initial ramdisk verification
2554 -120 common/image.c Ramdisk FIT image has incorrect format
2555 121 common/image.c Ramdisk FIT image has correct format
2556 122 common/image.c No ramdisk subimage unit name, using configuration
2557 -122 common/image.c Can't get configuration for ramdisk subimage
2558 123 common/image.c Ramdisk unit name specified
2559 -124 common/image.c Can't get ramdisk subimage node offset
2560 125 common/image.c Got ramdisk subimage node offset
2561 -125 common/image.c Ramdisk subimage hash verification failed
2562 126 common/image.c Ramdisk subimage hash verification OK
2563 -126 common/image.c Ramdisk subimage for unsupported architecture
2564 127 common/image.c Architecture check OK
2565 -127 common/image.c Can't get ramdisk subimage data/size
2566 128 common/image.c Got ramdisk subimage data/size
2567 129 common/image.c Can't get ramdisk load address
2568 -129 common/image.c Got ramdisk load address
2570 -130 common/cmd_doc.c Incorrect FIT image format
2571 131 common/cmd_doc.c FIT image format OK
2573 -140 common/cmd_ide.c Incorrect FIT image format
2574 141 common/cmd_ide.c FIT image format OK
2576 -150 common/cmd_nand.c Incorrect FIT image format
2577 151 common/cmd_nand.c FIT image format OK
2579 - Standalone program support:
2580 CONFIG_STANDALONE_LOAD_ADDR
2582 This option defines a board specific value for the
2583 address where standalone program gets loaded, thus
2584 overwriting the architecture dependent default
2587 - Frame Buffer Address:
2590 Define CONFIG_FB_ADDR if you want to use specific
2591 address for frame buffer.
2592 Then system will reserve the frame buffer address to
2593 defined address instead of lcd_setmem (this function
2594 grabs the memory for frame buffer by panel's size).
2596 Please see board_init_f function.
2598 - Automatic software updates via TFTP server
2600 CONFIG_UPDATE_TFTP_CNT_MAX
2601 CONFIG_UPDATE_TFTP_MSEC_MAX
2603 These options enable and control the auto-update feature;
2604 for a more detailed description refer to doc/README.update.
2606 - MTD Support (mtdparts command, UBI support)
2609 Adds the MTD device infrastructure from the Linux kernel.
2610 Needed for mtdparts command support.
2612 CONFIG_MTD_PARTITIONS
2614 Adds the MTD partitioning infrastructure from the Linux
2615 kernel. Needed for UBI support.
2619 Enable building of SPL globally.
2622 LDSCRIPT for linking the SPL binary.
2625 Maximum binary size (text, data and rodata) of the SPL binary.
2627 CONFIG_SPL_TEXT_BASE
2628 TEXT_BASE for linking the SPL binary.
2630 CONFIG_SPL_BSS_START_ADDR
2631 Link address for the BSS within the SPL binary.
2633 CONFIG_SPL_BSS_MAX_SIZE
2634 Maximum binary size of the BSS section of the SPL binary.
2637 Adress of the start of the stack SPL will use
2639 CONFIG_SYS_SPL_MALLOC_START
2640 Starting address of the malloc pool used in SPL.
2642 CONFIG_SYS_SPL_MALLOC_SIZE
2643 The size of the malloc pool used in SPL.
2645 CONFIG_SPL_FRAMEWORK
2646 Enable the SPL framework under common/. This framework
2647 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2648 NAND loading of the Linux Kernel.
2650 CONFIG_SPL_DISPLAY_PRINT
2651 For ARM, enable an optional function to print more information
2652 about the running system.
2654 CONFIG_SPL_LIBCOMMON_SUPPORT
2655 Support for common/libcommon.o in SPL binary
2657 CONFIG_SPL_LIBDISK_SUPPORT
2658 Support for disk/libdisk.o in SPL binary
2660 CONFIG_SPL_I2C_SUPPORT
2661 Support for drivers/i2c/libi2c.o in SPL binary
2663 CONFIG_SPL_GPIO_SUPPORT
2664 Support for drivers/gpio/libgpio.o in SPL binary
2666 CONFIG_SPL_MMC_SUPPORT
2667 Support for drivers/mmc/libmmc.o in SPL binary
2669 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2670 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2671 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2672 Address, size and partition on the MMC to load U-Boot from
2673 when the MMC is being used in raw mode.
2675 CONFIG_SPL_FAT_SUPPORT
2676 Support for fs/fat/libfat.o in SPL binary
2678 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2679 Filename to read to load U-Boot when reading from FAT
2681 CONFIG_SPL_NAND_SIMPLE
2682 Support for drivers/mtd/nand/libnand.o in SPL binary
2684 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2685 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2686 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2687 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2688 CONFIG_SYS_NAND_ECCBYTES
2689 Defines the size and behavior of the NAND that SPL uses
2690 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2692 CONFIG_SYS_NAND_U_BOOT_OFFS
2693 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2696 CONFIG_SYS_NAND_U_BOOT_START
2697 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2700 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2701 Define this if you need to first read the OOB and then the
2702 data. This is used for example on davinci plattforms.
2704 CONFIG_SPL_OMAP3_ID_NAND
2705 Support for an OMAP3-specific set of functions to return the
2706 ID and MFR of the first attached NAND chip, if present.
2708 CONFIG_SPL_SERIAL_SUPPORT
2709 Support for drivers/serial/libserial.o in SPL binary
2711 CONFIG_SPL_SPI_FLASH_SUPPORT
2712 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2714 CONFIG_SPL_SPI_SUPPORT
2715 Support for drivers/spi/libspi.o in SPL binary
2717 CONFIG_SPL_RAM_DEVICE
2718 Support for running image already present in ram, in SPL binary
2720 CONFIG_SPL_LIBGENERIC_SUPPORT
2721 Support for lib/libgeneric.o in SPL binary
2726 [so far only for SMDK2400 boards]
2728 - Modem support enable:
2729 CONFIG_MODEM_SUPPORT
2731 - RTS/CTS Flow control enable:
2734 - Modem debug support:
2735 CONFIG_MODEM_SUPPORT_DEBUG
2737 Enables debugging stuff (char screen[1024], dbg())
2738 for modem support. Useful only with BDI2000.
2740 - Interrupt support (PPC):
2742 There are common interrupt_init() and timer_interrupt()
2743 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2744 for CPU specific initialization. interrupt_init_cpu()
2745 should set decrementer_count to appropriate value. If
2746 CPU resets decrementer automatically after interrupt
2747 (ppc4xx) it should set decrementer_count to zero.
2748 timer_interrupt() calls timer_interrupt_cpu() for CPU
2749 specific handling. If board has watchdog / status_led
2750 / other_activity_monitor it works automatically from
2751 general timer_interrupt().
2755 In the target system modem support is enabled when a
2756 specific key (key combination) is pressed during
2757 power-on. Otherwise U-Boot will boot normally
2758 (autoboot). The key_pressed() function is called from
2759 board_init(). Currently key_pressed() is a dummy
2760 function, returning 1 and thus enabling modem
2763 If there are no modem init strings in the
2764 environment, U-Boot proceed to autoboot; the
2765 previous output (banner, info printfs) will be
2768 See also: doc/README.Modem
2770 Board initialization settings:
2771 ------------------------------
2773 During Initialization u-boot calls a number of board specific functions
2774 to allow the preparation of board specific prerequisites, e.g. pin setup
2775 before drivers are initialized. To enable these callbacks the
2776 following configuration macros have to be defined. Currently this is
2777 architecture specific, so please check arch/your_architecture/lib/board.c
2778 typically in board_init_f() and board_init_r().
2780 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2781 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2782 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2783 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2785 Configuration Settings:
2786 -----------------------
2788 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2789 undefine this when you're short of memory.
2791 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2792 width of the commands listed in the 'help' command output.
2794 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2795 prompt for user input.
2797 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2799 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2801 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2803 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2804 the application (usually a Linux kernel) when it is
2807 - CONFIG_SYS_BAUDRATE_TABLE:
2808 List of legal baudrate settings for this board.
2810 - CONFIG_SYS_CONSOLE_INFO_QUIET
2811 Suppress display of console information at boot.
2813 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2814 If the board specific function
2815 extern int overwrite_console (void);
2816 returns 1, the stdin, stderr and stdout are switched to the
2817 serial port, else the settings in the environment are used.
2819 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2820 Enable the call to overwrite_console().
2822 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2823 Enable overwrite of previous console environment settings.
2825 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2826 Begin and End addresses of the area used by the
2829 - CONFIG_SYS_ALT_MEMTEST:
2830 Enable an alternate, more extensive memory test.
2832 - CONFIG_SYS_MEMTEST_SCRATCH:
2833 Scratch address used by the alternate memory test
2834 You only need to set this if address zero isn't writeable
2836 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2837 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2838 this specified memory area will get subtracted from the top
2839 (end) of RAM and won't get "touched" at all by U-Boot. By
2840 fixing up gd->ram_size the Linux kernel should gets passed
2841 the now "corrected" memory size and won't touch it either.
2842 This should work for arch/ppc and arch/powerpc. Only Linux
2843 board ports in arch/powerpc with bootwrapper support that
2844 recalculate the memory size from the SDRAM controller setup
2845 will have to get fixed in Linux additionally.
2847 This option can be used as a workaround for the 440EPx/GRx
2848 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2851 WARNING: Please make sure that this value is a multiple of
2852 the Linux page size (normally 4k). If this is not the case,
2853 then the end address of the Linux memory will be located at a
2854 non page size aligned address and this could cause major
2857 - CONFIG_SYS_TFTP_LOADADDR:
2858 Default load address for network file downloads
2860 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2861 Enable temporary baudrate change while serial download
2863 - CONFIG_SYS_SDRAM_BASE:
2864 Physical start address of SDRAM. _Must_ be 0 here.
2866 - CONFIG_SYS_MBIO_BASE:
2867 Physical start address of Motherboard I/O (if using a
2870 - CONFIG_SYS_FLASH_BASE:
2871 Physical start address of Flash memory.
2873 - CONFIG_SYS_MONITOR_BASE:
2874 Physical start address of boot monitor code (set by
2875 make config files to be same as the text base address
2876 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2877 CONFIG_SYS_FLASH_BASE when booting from flash.
2879 - CONFIG_SYS_MONITOR_LEN:
2880 Size of memory reserved for monitor code, used to
2881 determine _at_compile_time_ (!) if the environment is
2882 embedded within the U-Boot image, or in a separate
2885 - CONFIG_SYS_MALLOC_LEN:
2886 Size of DRAM reserved for malloc() use.
2888 - CONFIG_SYS_BOOTM_LEN:
2889 Normally compressed uImages are limited to an
2890 uncompressed size of 8 MBytes. If this is not enough,
2891 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2892 to adjust this setting to your needs.
2894 - CONFIG_SYS_BOOTMAPSZ:
2895 Maximum size of memory mapped by the startup code of
2896 the Linux kernel; all data that must be processed by
2897 the Linux kernel (bd_info, boot arguments, FDT blob if
2898 used) must be put below this limit, unless "bootm_low"
2899 enviroment variable is defined and non-zero. In such case
2900 all data for the Linux kernel must be between "bootm_low"
2901 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2902 variable "bootm_mapsize" will override the value of
2903 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2904 then the value in "bootm_size" will be used instead.
2906 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2907 Enable initrd_high functionality. If defined then the
2908 initrd_high feature is enabled and the bootm ramdisk subcommand
2911 - CONFIG_SYS_BOOT_GET_CMDLINE:
2912 Enables allocating and saving kernel cmdline in space between
2913 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2915 - CONFIG_SYS_BOOT_GET_KBD:
2916 Enables allocating and saving a kernel copy of the bd_info in
2917 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2919 - CONFIG_SYS_MAX_FLASH_BANKS:
2920 Max number of Flash memory banks
2922 - CONFIG_SYS_MAX_FLASH_SECT:
2923 Max number of sectors on a Flash chip
2925 - CONFIG_SYS_FLASH_ERASE_TOUT:
2926 Timeout for Flash erase operations (in ms)
2928 - CONFIG_SYS_FLASH_WRITE_TOUT:
2929 Timeout for Flash write operations (in ms)
2931 - CONFIG_SYS_FLASH_LOCK_TOUT
2932 Timeout for Flash set sector lock bit operation (in ms)
2934 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2935 Timeout for Flash clear lock bits operation (in ms)
2937 - CONFIG_SYS_FLASH_PROTECTION
2938 If defined, hardware flash sectors protection is used
2939 instead of U-Boot software protection.
2941 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2943 Enable TFTP transfers directly to flash memory;
2944 without this option such a download has to be
2945 performed in two steps: (1) download to RAM, and (2)
2946 copy from RAM to flash.
2948 The two-step approach is usually more reliable, since
2949 you can check if the download worked before you erase
2950 the flash, but in some situations (when system RAM is
2951 too limited to allow for a temporary copy of the
2952 downloaded image) this option may be very useful.
2954 - CONFIG_SYS_FLASH_CFI:
2955 Define if the flash driver uses extra elements in the
2956 common flash structure for storing flash geometry.
2958 - CONFIG_FLASH_CFI_DRIVER
2959 This option also enables the building of the cfi_flash driver
2960 in the drivers directory
2962 - CONFIG_FLASH_CFI_MTD
2963 This option enables the building of the cfi_mtd driver
2964 in the drivers directory. The driver exports CFI flash
2967 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2968 Use buffered writes to flash.
2970 - CONFIG_FLASH_SPANSION_S29WS_N
2971 s29ws-n MirrorBit flash has non-standard addresses for buffered
2974 - CONFIG_SYS_FLASH_QUIET_TEST
2975 If this option is defined, the common CFI flash doesn't
2976 print it's warning upon not recognized FLASH banks. This
2977 is useful, if some of the configured banks are only
2978 optionally available.
2980 - CONFIG_FLASH_SHOW_PROGRESS
2981 If defined (must be an integer), print out countdown
2982 digits and dots. Recommended value: 45 (9..1) for 80
2983 column displays, 15 (3..1) for 40 column displays.
2985 - CONFIG_SYS_RX_ETH_BUFFER:
2986 Defines the number of Ethernet receive buffers. On some
2987 Ethernet controllers it is recommended to set this value
2988 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2989 buffers can be full shortly after enabling the interface
2990 on high Ethernet traffic.
2991 Defaults to 4 if not defined.
2993 - CONFIG_ENV_MAX_ENTRIES
2995 Maximum number of entries in the hash table that is used
2996 internally to store the environment settings. The default
2997 setting is supposed to be generous and should work in most
2998 cases. This setting can be used to tune behaviour; see
2999 lib/hashtable.c for details.
3001 The following definitions that deal with the placement and management
3002 of environment data (variable area); in general, we support the
3003 following configurations:
3005 - CONFIG_BUILD_ENVCRC:
3007 Builds up envcrc with the target environment so that external utils
3008 may easily extract it and embed it in final U-Boot images.
3010 - CONFIG_ENV_IS_IN_FLASH:
3012 Define this if the environment is in flash memory.
3014 a) The environment occupies one whole flash sector, which is
3015 "embedded" in the text segment with the U-Boot code. This
3016 happens usually with "bottom boot sector" or "top boot
3017 sector" type flash chips, which have several smaller
3018 sectors at the start or the end. For instance, such a
3019 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3020 such a case you would place the environment in one of the
3021 4 kB sectors - with U-Boot code before and after it. With
3022 "top boot sector" type flash chips, you would put the
3023 environment in one of the last sectors, leaving a gap
3024 between U-Boot and the environment.
3026 - CONFIG_ENV_OFFSET:
3028 Offset of environment data (variable area) to the
3029 beginning of flash memory; for instance, with bottom boot
3030 type flash chips the second sector can be used: the offset
3031 for this sector is given here.
3033 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3037 This is just another way to specify the start address of
3038 the flash sector containing the environment (instead of
3041 - CONFIG_ENV_SECT_SIZE:
3043 Size of the sector containing the environment.
3046 b) Sometimes flash chips have few, equal sized, BIG sectors.
3047 In such a case you don't want to spend a whole sector for
3052 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3053 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3054 of this flash sector for the environment. This saves
3055 memory for the RAM copy of the environment.
3057 It may also save flash memory if you decide to use this
3058 when your environment is "embedded" within U-Boot code,
3059 since then the remainder of the flash sector could be used
3060 for U-Boot code. It should be pointed out that this is
3061 STRONGLY DISCOURAGED from a robustness point of view:
3062 updating the environment in flash makes it always
3063 necessary to erase the WHOLE sector. If something goes
3064 wrong before the contents has been restored from a copy in
3065 RAM, your target system will be dead.
3067 - CONFIG_ENV_ADDR_REDUND
3068 CONFIG_ENV_SIZE_REDUND
3070 These settings describe a second storage area used to hold
3071 a redundant copy of the environment data, so that there is
3072 a valid backup copy in case there is a power failure during
3073 a "saveenv" operation.
3075 BE CAREFUL! Any changes to the flash layout, and some changes to the
3076 source code will make it necessary to adapt <board>/u-boot.lds*
3080 - CONFIG_ENV_IS_IN_NVRAM:
3082 Define this if you have some non-volatile memory device
3083 (NVRAM, battery buffered SRAM) which you want to use for the
3089 These two #defines are used to determine the memory area you
3090 want to use for environment. It is assumed that this memory
3091 can just be read and written to, without any special
3094 BE CAREFUL! The first access to the environment happens quite early
3095 in U-Boot initalization (when we try to get the setting of for the
3096 console baudrate). You *MUST* have mapped your NVRAM area then, or
3099 Please note that even with NVRAM we still use a copy of the
3100 environment in RAM: we could work on NVRAM directly, but we want to
3101 keep settings there always unmodified except somebody uses "saveenv"
3102 to save the current settings.
3105 - CONFIG_ENV_IS_IN_EEPROM:
3107 Use this if you have an EEPROM or similar serial access
3108 device and a driver for it.
3110 - CONFIG_ENV_OFFSET:
3113 These two #defines specify the offset and size of the
3114 environment area within the total memory of your EEPROM.
3116 - CONFIG_SYS_I2C_EEPROM_ADDR:
3117 If defined, specified the chip address of the EEPROM device.
3118 The default address is zero.
3120 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3121 If defined, the number of bits used to address bytes in a
3122 single page in the EEPROM device. A 64 byte page, for example
3123 would require six bits.
3125 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3126 If defined, the number of milliseconds to delay between
3127 page writes. The default is zero milliseconds.
3129 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3130 The length in bytes of the EEPROM memory array address. Note
3131 that this is NOT the chip address length!
3133 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3134 EEPROM chips that implement "address overflow" are ones
3135 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3136 address and the extra bits end up in the "chip address" bit
3137 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3140 Note that we consider the length of the address field to
3141 still be one byte because the extra address bits are hidden
3142 in the chip address.
3144 - CONFIG_SYS_EEPROM_SIZE:
3145 The size in bytes of the EEPROM device.
3147 - CONFIG_ENV_EEPROM_IS_ON_I2C
3148 define this, if you have I2C and SPI activated, and your
3149 EEPROM, which holds the environment, is on the I2C bus.
3151 - CONFIG_I2C_ENV_EEPROM_BUS
3152 if you have an Environment on an EEPROM reached over
3153 I2C muxes, you can define here, how to reach this
3154 EEPROM. For example:
3156 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3158 EEPROM which holds the environment, is reached over
3159 a pca9547 i2c mux with address 0x70, channel 3.
3161 - CONFIG_ENV_IS_IN_DATAFLASH:
3163 Define this if you have a DataFlash memory device which you
3164 want to use for the environment.
3166 - CONFIG_ENV_OFFSET:
3170 These three #defines specify the offset and size of the
3171 environment area within the total memory of your DataFlash placed
3172 at the specified address.
3174 - CONFIG_ENV_IS_IN_REMOTE:
3176 Define this if you have a remote memory space which you
3177 want to use for the local device's environment.
3182 These two #defines specify the address and size of the
3183 environment area within the remote memory space. The
3184 local device can get the environment from remote memory
3185 space by SRIO or PCIE links.
3187 BE CAREFUL! For some special cases, the local device can not use
3188 "saveenv" command. For example, the local device will get the
3189 environment stored in a remote NOR flash by SRIO or PCIE link,
3190 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3192 - CONFIG_ENV_IS_IN_NAND:
3194 Define this if you have a NAND device which you want to use
3195 for the environment.
3197 - CONFIG_ENV_OFFSET:
3200 These two #defines specify the offset and size of the environment
3201 area within the first NAND device. CONFIG_ENV_OFFSET must be
3202 aligned to an erase block boundary.
3204 - CONFIG_ENV_OFFSET_REDUND (optional):
3206 This setting describes a second storage area of CONFIG_ENV_SIZE
3207 size used to hold a redundant copy of the environment data, so
3208 that there is a valid backup copy in case there is a power failure
3209 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3210 aligned to an erase block boundary.
3212 - CONFIG_ENV_RANGE (optional):
3214 Specifies the length of the region in which the environment
3215 can be written. This should be a multiple of the NAND device's
3216 block size. Specifying a range with more erase blocks than
3217 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3218 the range to be avoided.
3220 - CONFIG_ENV_OFFSET_OOB (optional):
3222 Enables support for dynamically retrieving the offset of the
3223 environment from block zero's out-of-band data. The
3224 "nand env.oob" command can be used to record this offset.
3225 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3226 using CONFIG_ENV_OFFSET_OOB.
3228 - CONFIG_NAND_ENV_DST
3230 Defines address in RAM to which the nand_spl code should copy the
3231 environment. If redundant environment is used, it will be copied to
3232 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3234 - CONFIG_SYS_SPI_INIT_OFFSET
3236 Defines offset to the initial SPI buffer area in DPRAM. The
3237 area is used at an early stage (ROM part) if the environment
3238 is configured to reside in the SPI EEPROM: We need a 520 byte
3239 scratch DPRAM area. It is used between the two initialization
3240 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3241 to be a good choice since it makes it far enough from the
3242 start of the data area as well as from the stack pointer.
3244 Please note that the environment is read-only until the monitor
3245 has been relocated to RAM and a RAM copy of the environment has been
3246 created; also, when using EEPROM you will have to use getenv_f()
3247 until then to read environment variables.
3249 The environment is protected by a CRC32 checksum. Before the monitor
3250 is relocated into RAM, as a result of a bad CRC you will be working
3251 with the compiled-in default environment - *silently*!!! [This is
3252 necessary, because the first environment variable we need is the
3253 "baudrate" setting for the console - if we have a bad CRC, we don't
3254 have any device yet where we could complain.]
3256 Note: once the monitor has been relocated, then it will complain if
3257 the default environment is used; a new CRC is computed as soon as you
3258 use the "saveenv" command to store a valid environment.
3260 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3261 Echo the inverted Ethernet link state to the fault LED.
3263 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3264 also needs to be defined.
3266 - CONFIG_SYS_FAULT_MII_ADDR:
3267 MII address of the PHY to check for the Ethernet link state.
3269 - CONFIG_NS16550_MIN_FUNCTIONS:
3270 Define this if you desire to only have use of the NS16550_init
3271 and NS16550_putc functions for the serial driver located at
3272 drivers/serial/ns16550.c. This option is useful for saving
3273 space for already greatly restricted images, including but not
3274 limited to NAND_SPL configurations.
3276 Low Level (hardware related) configuration options:
3277 ---------------------------------------------------
3279 - CONFIG_SYS_CACHELINE_SIZE:
3280 Cache Line Size of the CPU.
3282 - CONFIG_SYS_DEFAULT_IMMR:
3283 Default address of the IMMR after system reset.
3285 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3286 and RPXsuper) to be able to adjust the position of
3287 the IMMR register after a reset.
3289 - CONFIG_SYS_CCSRBAR_DEFAULT:
3290 Default (power-on reset) physical address of CCSR on Freescale
3293 - CONFIG_SYS_CCSRBAR:
3294 Virtual address of CCSR. On a 32-bit build, this is typically
3295 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3297 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3298 for cross-platform code that uses that macro instead.
3300 - CONFIG_SYS_CCSRBAR_PHYS:
3301 Physical address of CCSR. CCSR can be relocated to a new
3302 physical address, if desired. In this case, this macro should
3303 be set to that address. Otherwise, it should be set to the
3304 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3305 is typically relocated on 36-bit builds. It is recommended
3306 that this macro be defined via the _HIGH and _LOW macros:
3308 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3309 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3311 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3312 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3313 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3314 used in assembly code, so it must not contain typecasts or
3315 integer size suffixes (e.g. "ULL").
3317 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3318 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3319 used in assembly code, so it must not contain typecasts or
3320 integer size suffixes (e.g. "ULL").
3322 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3323 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3324 forced to a value that ensures that CCSR is not relocated.
3326 - Floppy Disk Support:
3327 CONFIG_SYS_FDC_DRIVE_NUMBER
3329 the default drive number (default value 0)
3331 CONFIG_SYS_ISA_IO_STRIDE
3333 defines the spacing between FDC chipset registers
3336 CONFIG_SYS_ISA_IO_OFFSET
3338 defines the offset of register from address. It
3339 depends on which part of the data bus is connected to
3340 the FDC chipset. (default value 0)
3342 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3343 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3346 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3347 fdc_hw_init() is called at the beginning of the FDC
3348 setup. fdc_hw_init() must be provided by the board
3349 source code. It is used to make hardware dependant
3353 Most IDE controllers were designed to be connected with PCI
3354 interface. Only few of them were designed for AHB interface.
3355 When software is doing ATA command and data transfer to
3356 IDE devices through IDE-AHB controller, some additional
3357 registers accessing to these kind of IDE-AHB controller
3360 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3361 DO NOT CHANGE unless you know exactly what you're
3362 doing! (11-4) [MPC8xx/82xx systems only]
3364 - CONFIG_SYS_INIT_RAM_ADDR:
3366 Start address of memory area that can be used for
3367 initial data and stack; please note that this must be
3368 writable memory that is working WITHOUT special
3369 initialization, i. e. you CANNOT use normal RAM which
3370 will become available only after programming the
3371 memory controller and running certain initialization
3374 U-Boot uses the following memory types:
3375 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3376 - MPC824X: data cache
3377 - PPC4xx: data cache
3379 - CONFIG_SYS_GBL_DATA_OFFSET:
3381 Offset of the initial data structure in the memory
3382 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3383 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3384 data is located at the end of the available space
3385 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3386 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3387 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3388 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3391 On the MPC824X (or other systems that use the data
3392 cache for initial memory) the address chosen for
3393 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3394 point to an otherwise UNUSED address space between
3395 the top of RAM and the start of the PCI space.
3397 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3399 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3401 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3403 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3405 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3407 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3409 - CONFIG_SYS_OR_TIMING_SDRAM:
3412 - CONFIG_SYS_MAMR_PTA:
3413 periodic timer for refresh
3415 - CONFIG_SYS_DER: Debug Event Register (37-47)
3417 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3418 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3419 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3420 CONFIG_SYS_BR1_PRELIM:
3421 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3423 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3424 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3425 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3426 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3428 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3429 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3430 Machine Mode Register and Memory Periodic Timer
3431 Prescaler definitions (SDRAM timing)
3433 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3434 enable I2C microcode relocation patch (MPC8xx);
3435 define relocation offset in DPRAM [DSP2]
3437 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3438 enable SMC microcode relocation patch (MPC8xx);
3439 define relocation offset in DPRAM [SMC1]
3441 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3442 enable SPI microcode relocation patch (MPC8xx);
3443 define relocation offset in DPRAM [SCC4]
3445 - CONFIG_SYS_USE_OSCCLK:
3446 Use OSCM clock mode on MBX8xx board. Be careful,
3447 wrong setting might damage your board. Read
3448 doc/README.MBX before setting this variable!
3450 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3451 Offset of the bootmode word in DPRAM used by post
3452 (Power On Self Tests). This definition overrides
3453 #define'd default value in commproc.h resp.
3456 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3457 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3458 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3459 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3460 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3461 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3462 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3463 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3464 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3466 - CONFIG_PCI_DISABLE_PCIE:
3467 Disable PCI-Express on systems where it is supported but not
3470 - CONFIG_PCI_ENUM_ONLY
3471 Only scan through and get the devices on the busses.
3472 Don't do any setup work, presumably because someone or
3473 something has already done it, and we don't need to do it
3474 a second time. Useful for platforms that are pre-booted
3475 by coreboot or similar.
3478 Chip has SRIO or not
3481 Board has SRIO 1 port available
3484 Board has SRIO 2 port available
3486 - CONFIG_SYS_SRIOn_MEM_VIRT:
3487 Virtual Address of SRIO port 'n' memory region
3489 - CONFIG_SYS_SRIOn_MEM_PHYS:
3490 Physical Address of SRIO port 'n' memory region
3492 - CONFIG_SYS_SRIOn_MEM_SIZE:
3493 Size of SRIO port 'n' memory region
3495 - CONFIG_SYS_NDFC_16
3496 Defined to tell the NDFC that the NAND chip is using a
3499 - CONFIG_SYS_NDFC_EBC0_CFG
3500 Sets the EBC0_CFG register for the NDFC. If not defined
3501 a default value will be used.
3504 Get DDR timing information from an I2C EEPROM. Common
3505 with pluggable memory modules such as SODIMMs
3508 I2C address of the SPD EEPROM
3510 - CONFIG_SYS_SPD_BUS_NUM
3511 If SPD EEPROM is on an I2C bus other than the first
3512 one, specify here. Note that the value must resolve
3513 to something your driver can deal with.
3515 - CONFIG_SYS_DDR_RAW_TIMING
3516 Get DDR timing information from other than SPD. Common with
3517 soldered DDR chips onboard without SPD. DDR raw timing
3518 parameters are extracted from datasheet and hard-coded into
3519 header files or board specific files.
3521 - CONFIG_FSL_DDR_INTERACTIVE
3522 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3524 - CONFIG_SYS_83XX_DDR_USES_CS0
3525 Only for 83xx systems. If specified, then DDR should
3526 be configured using CS0 and CS1 instead of CS2 and CS3.
3528 - CONFIG_ETHER_ON_FEC[12]
3529 Define to enable FEC[12] on a 8xx series processor.
3531 - CONFIG_FEC[12]_PHY
3532 Define to the hardcoded PHY address which corresponds
3533 to the given FEC; i. e.
3534 #define CONFIG_FEC1_PHY 4
3535 means that the PHY with address 4 is connected to FEC1
3537 When set to -1, means to probe for first available.
3539 - CONFIG_FEC[12]_PHY_NORXERR
3540 The PHY does not have a RXERR line (RMII only).
3541 (so program the FEC to ignore it).
3544 Enable RMII mode for all FECs.
3545 Note that this is a global option, we can't
3546 have one FEC in standard MII mode and another in RMII mode.
3548 - CONFIG_CRC32_VERIFY
3549 Add a verify option to the crc32 command.
3552 => crc32 -v <address> <count> <crc32>
3554 Where address/count indicate a memory area
3555 and crc32 is the correct crc32 which the
3559 Add the "loopw" memory command. This only takes effect if
3560 the memory commands are activated globally (CONFIG_CMD_MEM).
3563 Add the "mdc" and "mwc" memory commands. These are cyclic
3568 This command will print 4 bytes (10,11,12,13) each 500 ms.
3570 => mwc.l 100 12345678 10
3571 This command will write 12345678 to address 100 all 10 ms.
3573 This only takes effect if the memory commands are activated
3574 globally (CONFIG_CMD_MEM).
3576 - CONFIG_SKIP_LOWLEVEL_INIT
3577 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3578 low level initializations (like setting up the memory
3579 controller) are omitted and/or U-Boot does not
3580 relocate itself into RAM.
3582 Normally this variable MUST NOT be defined. The only
3583 exception is when U-Boot is loaded (to RAM) by some
3584 other boot loader or by a debugger which performs
3585 these initializations itself.
3588 Modifies the behaviour of start.S when compiling a loader
3589 that is executed before the actual U-Boot. E.g. when
3590 compiling a NAND SPL.
3592 - CONFIG_USE_ARCH_MEMCPY
3593 CONFIG_USE_ARCH_MEMSET
3594 If these options are used a optimized version of memcpy/memset will
3595 be used if available. These functions may be faster under some
3596 conditions but may increase the binary size.
3598 Freescale QE/FMAN Firmware Support:
3599 -----------------------------------
3601 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3602 loading of "firmware", which is encoded in the QE firmware binary format.
3603 This firmware often needs to be loaded during U-Boot booting, so macros
3604 are used to identify the storage device (NOR flash, SPI, etc) and the address
3607 - CONFIG_SYS_QE_FMAN_FW_ADDR
3608 The address in the storage device where the firmware is located. The
3609 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3612 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3613 The maximum possible size of the firmware. The firmware binary format
3614 has a field that specifies the actual size of the firmware, but it
3615 might not be possible to read any part of the firmware unless some
3616 local storage is allocated to hold the entire firmware first.
3618 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3619 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3620 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3621 virtual address in NOR flash.
3623 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3624 Specifies that QE/FMAN firmware is located in NAND flash.
3625 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3627 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3628 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3629 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3631 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3632 Specifies that QE/FMAN firmware is located on the primary SPI
3633 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3635 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3636 Specifies that QE/FMAN firmware is located in the remote (master)
3637 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3638 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3639 window->master inbound window->master LAW->the ucode address in
3640 master's memory space.
3642 Building the Software:
3643 ======================
3645 Building U-Boot has been tested in several native build environments
3646 and in many different cross environments. Of course we cannot support
3647 all possibly existing versions of cross development tools in all
3648 (potentially obsolete) versions. In case of tool chain problems we
3649 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3650 which is extensively used to build and test U-Boot.
3652 If you are not using a native environment, it is assumed that you
3653 have GNU cross compiling tools available in your path. In this case,
3654 you must set the environment variable CROSS_COMPILE in your shell.
3655 Note that no changes to the Makefile or any other source files are
3656 necessary. For example using the ELDK on a 4xx CPU, please enter:
3658 $ CROSS_COMPILE=ppc_4xx-
3659 $ export CROSS_COMPILE
3661 Note: If you wish to generate Windows versions of the utilities in
3662 the tools directory you can use the MinGW toolchain
3663 (http://www.mingw.org). Set your HOST tools to the MinGW
3664 toolchain and execute 'make tools'. For example:
3666 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3668 Binaries such as tools/mkimage.exe will be created which can
3669 be executed on computers running Windows.
3671 U-Boot is intended to be simple to build. After installing the
3672 sources you must configure U-Boot for one specific board type. This
3677 where "NAME_config" is the name of one of the existing configu-
3678 rations; see boards.cfg for supported names.
3680 Note: for some board special configuration names may exist; check if
3681 additional information is available from the board vendor; for
3682 instance, the TQM823L systems are available without (standard)
3683 or with LCD support. You can select such additional "features"
3684 when choosing the configuration, i. e.
3687 - will configure for a plain TQM823L, i. e. no LCD support
3689 make TQM823L_LCD_config
3690 - will configure for a TQM823L with U-Boot console on LCD
3695 Finally, type "make all", and you should get some working U-Boot
3696 images ready for download to / installation on your system:
3698 - "u-boot.bin" is a raw binary image
3699 - "u-boot" is an image in ELF binary format
3700 - "u-boot.srec" is in Motorola S-Record format
3702 By default the build is performed locally and the objects are saved
3703 in the source directory. One of the two methods can be used to change
3704 this behavior and build U-Boot to some external directory:
3706 1. Add O= to the make command line invocations:
3708 make O=/tmp/build distclean
3709 make O=/tmp/build NAME_config
3710 make O=/tmp/build all
3712 2. Set environment variable BUILD_DIR to point to the desired location:
3714 export BUILD_DIR=/tmp/build
3719 Note that the command line "O=" setting overrides the BUILD_DIR environment
3723 Please be aware that the Makefiles assume you are using GNU make, so
3724 for instance on NetBSD you might need to use "gmake" instead of
3728 If the system board that you have is not listed, then you will need
3729 to port U-Boot to your hardware platform. To do this, follow these
3732 1. Add a new configuration option for your board to the toplevel
3733 "boards.cfg" file, using the existing entries as examples.
3734 Follow the instructions there to keep the boards in order.
3735 2. Create a new directory to hold your board specific code. Add any
3736 files you need. In your board directory, you will need at least
3737 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3738 3. Create a new configuration file "include/configs/<board>.h" for
3740 3. If you're porting U-Boot to a new CPU, then also create a new
3741 directory to hold your CPU specific code. Add any files you need.
3742 4. Run "make <board>_config" with your new name.
3743 5. Type "make", and you should get a working "u-boot.srec" file
3744 to be installed on your target system.
3745 6. Debug and solve any problems that might arise.
3746 [Of course, this last step is much harder than it sounds.]
3749 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3750 ==============================================================
3752 If you have modified U-Boot sources (for instance added a new board
3753 or support for new devices, a new CPU, etc.) you are expected to
3754 provide feedback to the other developers. The feedback normally takes
3755 the form of a "patch", i. e. a context diff against a certain (latest
3756 official or latest in the git repository) version of U-Boot sources.
3758 But before you submit such a patch, please verify that your modifi-
3759 cation did not break existing code. At least make sure that *ALL* of
3760 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3761 just run the "MAKEALL" script, which will configure and build U-Boot
3762 for ALL supported system. Be warned, this will take a while. You can
3763 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3764 environment variable to the script, i. e. to use the ELDK cross tools
3767 CROSS_COMPILE=ppc_8xx- MAKEALL
3769 or to build on a native PowerPC system you can type
3771 CROSS_COMPILE=' ' MAKEALL
3773 When using the MAKEALL script, the default behaviour is to build
3774 U-Boot in the source directory. This location can be changed by
3775 setting the BUILD_DIR environment variable. Also, for each target
3776 built, the MAKEALL script saves two log files (<target>.ERR and
3777 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3778 location can be changed by setting the MAKEALL_LOGDIR environment
3779 variable. For example:
3781 export BUILD_DIR=/tmp/build
3782 export MAKEALL_LOGDIR=/tmp/log
3783 CROSS_COMPILE=ppc_8xx- MAKEALL
3785 With the above settings build objects are saved in the /tmp/build,
3786 log files are saved in the /tmp/log and the source tree remains clean
3787 during the whole build process.
3790 See also "U-Boot Porting Guide" below.
3793 Monitor Commands - Overview:
3794 ============================
3796 go - start application at address 'addr'
3797 run - run commands in an environment variable
3798 bootm - boot application image from memory
3799 bootp - boot image via network using BootP/TFTP protocol
3800 bootz - boot zImage from memory
3801 tftpboot- boot image via network using TFTP protocol
3802 and env variables "ipaddr" and "serverip"
3803 (and eventually "gatewayip")
3804 tftpput - upload a file via network using TFTP protocol
3805 rarpboot- boot image via network using RARP/TFTP protocol
3806 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3807 loads - load S-Record file over serial line
3808 loadb - load binary file over serial line (kermit mode)
3810 mm - memory modify (auto-incrementing)
3811 nm - memory modify (constant address)
3812 mw - memory write (fill)
3814 cmp - memory compare
3815 crc32 - checksum calculation
3816 i2c - I2C sub-system
3817 sspi - SPI utility commands
3818 base - print or set address offset
3819 printenv- print environment variables
3820 setenv - set environment variables
3821 saveenv - save environment variables to persistent storage
3822 protect - enable or disable FLASH write protection
3823 erase - erase FLASH memory
3824 flinfo - print FLASH memory information
3825 bdinfo - print Board Info structure
3826 iminfo - print header information for application image
3827 coninfo - print console devices and informations
3828 ide - IDE sub-system
3829 loop - infinite loop on address range
3830 loopw - infinite write loop on address range
3831 mtest - simple RAM test
3832 icache - enable or disable instruction cache
3833 dcache - enable or disable data cache
3834 reset - Perform RESET of the CPU
3835 echo - echo args to console
3836 version - print monitor version
3837 help - print online help
3838 ? - alias for 'help'
3841 Monitor Commands - Detailed Description:
3842 ========================================
3846 For now: just type "help <command>".
3849 Environment Variables:
3850 ======================
3852 U-Boot supports user configuration using Environment Variables which
3853 can be made persistent by saving to Flash memory.
3855 Environment Variables are set using "setenv", printed using
3856 "printenv", and saved to Flash using "saveenv". Using "setenv"
3857 without a value can be used to delete a variable from the
3858 environment. As long as you don't save the environment you are
3859 working with an in-memory copy. In case the Flash area containing the
3860 environment is erased by accident, a default environment is provided.
3862 Some configuration options can be set using Environment Variables.
3864 List of environment variables (most likely not complete):
3866 baudrate - see CONFIG_BAUDRATE
3868 bootdelay - see CONFIG_BOOTDELAY
3870 bootcmd - see CONFIG_BOOTCOMMAND
3872 bootargs - Boot arguments when booting an RTOS image
3874 bootfile - Name of the image to load with TFTP
3876 bootm_low - Memory range available for image processing in the bootm
3877 command can be restricted. This variable is given as
3878 a hexadecimal number and defines lowest address allowed
3879 for use by the bootm command. See also "bootm_size"
3880 environment variable. Address defined by "bootm_low" is
3881 also the base of the initial memory mapping for the Linux
3882 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3885 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3886 This variable is given as a hexadecimal number and it
3887 defines the size of the memory region starting at base
3888 address bootm_low that is accessible by the Linux kernel
3889 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3890 as the default value if it is defined, and bootm_size is
3893 bootm_size - Memory range available for image processing in the bootm
3894 command can be restricted. This variable is given as
3895 a hexadecimal number and defines the size of the region
3896 allowed for use by the bootm command. See also "bootm_low"
3897 environment variable.
3899 updatefile - Location of the software update file on a TFTP server, used
3900 by the automatic software update feature. Please refer to
3901 documentation in doc/README.update for more details.
3903 autoload - if set to "no" (any string beginning with 'n'),
3904 "bootp" will just load perform a lookup of the
3905 configuration from the BOOTP server, but not try to
3906 load any image using TFTP
3908 autostart - if set to "yes", an image loaded using the "bootp",
3909 "rarpboot", "tftpboot" or "diskboot" commands will
3910 be automatically started (by internally calling
3913 If set to "no", a standalone image passed to the
3914 "bootm" command will be copied to the load address
3915 (and eventually uncompressed), but NOT be started.
3916 This can be used to load and uncompress arbitrary
3919 fdt_high - if set this restricts the maximum address that the
3920 flattened device tree will be copied into upon boot.
3921 For example, if you have a system with 1 GB memory
3922 at physical address 0x10000000, while Linux kernel
3923 only recognizes the first 704 MB as low memory, you
3924 may need to set fdt_high as 0x3C000000 to have the
3925 device tree blob be copied to the maximum address
3926 of the 704 MB low memory, so that Linux kernel can
3927 access it during the boot procedure.
3929 If this is set to the special value 0xFFFFFFFF then
3930 the fdt will not be copied at all on boot. For this
3931 to work it must reside in writable memory, have
3932 sufficient padding on the end of it for u-boot to
3933 add the information it needs into it, and the memory
3934 must be accessible by the kernel.
3936 fdtcontroladdr- if set this is the address of the control flattened
3937 device tree used by U-Boot when CONFIG_OF_CONTROL is
3940 i2cfast - (PPC405GP|PPC405EP only)
3941 if set to 'y' configures Linux I2C driver for fast
3942 mode (400kHZ). This environment variable is used in
3943 initialization code. So, for changes to be effective
3944 it must be saved and board must be reset.
3946 initrd_high - restrict positioning of initrd images:
3947 If this variable is not set, initrd images will be
3948 copied to the highest possible address in RAM; this
3949 is usually what you want since it allows for
3950 maximum initrd size. If for some reason you want to
3951 make sure that the initrd image is loaded below the
3952 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3953 variable to a value of "no" or "off" or "0".
3954 Alternatively, you can set it to a maximum upper
3955 address to use (U-Boot will still check that it
3956 does not overwrite the U-Boot stack and data).
3958 For instance, when you have a system with 16 MB
3959 RAM, and want to reserve 4 MB from use by Linux,
3960 you can do this by adding "mem=12M" to the value of
3961 the "bootargs" variable. However, now you must make
3962 sure that the initrd image is placed in the first
3963 12 MB as well - this can be done with
3965 setenv initrd_high 00c00000
3967 If you set initrd_high to 0xFFFFFFFF, this is an
3968 indication to U-Boot that all addresses are legal
3969 for the Linux kernel, including addresses in flash
3970 memory. In this case U-Boot will NOT COPY the
3971 ramdisk at all. This may be useful to reduce the
3972 boot time on your system, but requires that this
3973 feature is supported by your Linux kernel.
3975 ipaddr - IP address; needed for tftpboot command
3977 loadaddr - Default load address for commands like "bootp",
3978 "rarpboot", "tftpboot", "loadb" or "diskboot"
3980 loads_echo - see CONFIG_LOADS_ECHO
3982 serverip - TFTP server IP address; needed for tftpboot command
3984 bootretry - see CONFIG_BOOT_RETRY_TIME
3986 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3988 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3990 ethprime - controls which interface is used first.
3992 ethact - controls which interface is currently active.
3993 For example you can do the following
3995 => setenv ethact FEC
3996 => ping 192.168.0.1 # traffic sent on FEC
3997 => setenv ethact SCC
3998 => ping 10.0.0.1 # traffic sent on SCC
4000 ethrotate - When set to "no" U-Boot does not go through all
4001 available network interfaces.
4002 It just stays at the currently selected interface.
4004 netretry - When set to "no" each network operation will
4005 either succeed or fail without retrying.
4006 When set to "once" the network operation will
4007 fail when all the available network interfaces
4008 are tried once without success.
4009 Useful on scripts which control the retry operation
4012 npe_ucode - set load address for the NPE microcode
4014 tftpsrcport - If this is set, the value is used for TFTP's
4017 tftpdstport - If this is set, the value is used for TFTP's UDP
4018 destination port instead of the Well Know Port 69.
4020 tftpblocksize - Block size to use for TFTP transfers; if not set,
4021 we use the TFTP server's default block size
4023 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4024 seconds, minimum value is 1000 = 1 second). Defines
4025 when a packet is considered to be lost so it has to
4026 be retransmitted. The default is 5000 = 5 seconds.
4027 Lowering this value may make downloads succeed
4028 faster in networks with high packet loss rates or
4029 with unreliable TFTP servers.
4031 vlan - When set to a value < 4095 the traffic over
4032 Ethernet is encapsulated/received over 802.1q
4035 The following image location variables contain the location of images
4036 used in booting. The "Image" column gives the role of the image and is
4037 not an environment variable name. The other columns are environment
4038 variable names. "File Name" gives the name of the file on a TFTP
4039 server, "RAM Address" gives the location in RAM the image will be
4040 loaded to, and "Flash Location" gives the image's address in NOR
4041 flash or offset in NAND flash.
4043 *Note* - these variables don't have to be defined for all boards, some
4044 boards currenlty use other variables for these purposes, and some
4045 boards use these variables for other purposes.
4047 Image File Name RAM Address Flash Location
4048 ----- --------- ----------- --------------
4049 u-boot u-boot u-boot_addr_r u-boot_addr
4050 Linux kernel bootfile kernel_addr_r kernel_addr
4051 device tree blob fdtfile fdt_addr_r fdt_addr
4052 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4054 The following environment variables may be used and automatically
4055 updated by the network boot commands ("bootp" and "rarpboot"),
4056 depending the information provided by your boot server:
4058 bootfile - see above
4059 dnsip - IP address of your Domain Name Server
4060 dnsip2 - IP address of your secondary Domain Name Server
4061 gatewayip - IP address of the Gateway (Router) to use
4062 hostname - Target hostname
4064 netmask - Subnet Mask
4065 rootpath - Pathname of the root filesystem on the NFS server
4066 serverip - see above
4069 There are two special Environment Variables:
4071 serial# - contains hardware identification information such
4072 as type string and/or serial number
4073 ethaddr - Ethernet address
4075 These variables can be set only once (usually during manufacturing of
4076 the board). U-Boot refuses to delete or overwrite these variables
4077 once they have been set once.
4080 Further special Environment Variables:
4082 ver - Contains the U-Boot version string as printed
4083 with the "version" command. This variable is
4084 readonly (see CONFIG_VERSION_VARIABLE).
4087 Please note that changes to some configuration parameters may take
4088 only effect after the next boot (yes, that's just like Windoze :-).
4091 Command Line Parsing:
4092 =====================
4094 There are two different command line parsers available with U-Boot:
4095 the old "simple" one, and the much more powerful "hush" shell:
4097 Old, simple command line parser:
4098 --------------------------------
4100 - supports environment variables (through setenv / saveenv commands)
4101 - several commands on one line, separated by ';'
4102 - variable substitution using "... ${name} ..." syntax
4103 - special characters ('$', ';') can be escaped by prefixing with '\',
4105 setenv bootcmd bootm \${address}
4106 - You can also escape text by enclosing in single apostrophes, for example:
4107 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4112 - similar to Bourne shell, with control structures like
4113 if...then...else...fi, for...do...done; while...do...done,
4114 until...do...done, ...
4115 - supports environment ("global") variables (through setenv / saveenv
4116 commands) and local shell variables (through standard shell syntax
4117 "name=value"); only environment variables can be used with "run"
4123 (1) If a command line (or an environment variable executed by a "run"
4124 command) contains several commands separated by semicolon, and
4125 one of these commands fails, then the remaining commands will be
4128 (2) If you execute several variables with one call to run (i. e.
4129 calling run with a list of variables as arguments), any failing
4130 command will cause "run" to terminate, i. e. the remaining
4131 variables are not executed.
4133 Note for Redundant Ethernet Interfaces:
4134 =======================================
4136 Some boards come with redundant Ethernet interfaces; U-Boot supports
4137 such configurations and is capable of automatic selection of a
4138 "working" interface when needed. MAC assignment works as follows:
4140 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4141 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4142 "eth1addr" (=>eth1), "eth2addr", ...
4144 If the network interface stores some valid MAC address (for instance
4145 in SROM), this is used as default address if there is NO correspon-
4146 ding setting in the environment; if the corresponding environment
4147 variable is set, this overrides the settings in the card; that means:
4149 o If the SROM has a valid MAC address, and there is no address in the
4150 environment, the SROM's address is used.
4152 o If there is no valid address in the SROM, and a definition in the
4153 environment exists, then the value from the environment variable is
4156 o If both the SROM and the environment contain a MAC address, and
4157 both addresses are the same, this MAC address is used.
4159 o If both the SROM and the environment contain a MAC address, and the
4160 addresses differ, the value from the environment is used and a
4163 o If neither SROM nor the environment contain a MAC address, an error
4166 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4167 will be programmed into hardware as part of the initialization process. This
4168 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4169 The naming convention is as follows:
4170 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4175 U-Boot is capable of booting (and performing other auxiliary operations on)
4176 images in two formats:
4178 New uImage format (FIT)
4179 -----------------------
4181 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4182 to Flattened Device Tree). It allows the use of images with multiple
4183 components (several kernels, ramdisks, etc.), with contents protected by
4184 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4190 Old image format is based on binary files which can be basically anything,
4191 preceded by a special header; see the definitions in include/image.h for
4192 details; basically, the header defines the following image properties:
4194 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4195 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4196 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4197 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4199 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4200 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4201 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4202 * Compression Type (uncompressed, gzip, bzip2)
4208 The header is marked by a special Magic Number, and both the header
4209 and the data portions of the image are secured against corruption by
4216 Although U-Boot should support any OS or standalone application
4217 easily, the main focus has always been on Linux during the design of
4220 U-Boot includes many features that so far have been part of some
4221 special "boot loader" code within the Linux kernel. Also, any
4222 "initrd" images to be used are no longer part of one big Linux image;
4223 instead, kernel and "initrd" are separate images. This implementation
4224 serves several purposes:
4226 - the same features can be used for other OS or standalone
4227 applications (for instance: using compressed images to reduce the
4228 Flash memory footprint)
4230 - it becomes much easier to port new Linux kernel versions because
4231 lots of low-level, hardware dependent stuff are done by U-Boot
4233 - the same Linux kernel image can now be used with different "initrd"
4234 images; of course this also means that different kernel images can
4235 be run with the same "initrd". This makes testing easier (you don't
4236 have to build a new "zImage.initrd" Linux image when you just
4237 change a file in your "initrd"). Also, a field-upgrade of the
4238 software is easier now.
4244 Porting Linux to U-Boot based systems:
4245 ---------------------------------------
4247 U-Boot cannot save you from doing all the necessary modifications to
4248 configure the Linux device drivers for use with your target hardware
4249 (no, we don't intend to provide a full virtual machine interface to
4252 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4254 Just make sure your machine specific header file (for instance
4255 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4256 Information structure as we define in include/asm-<arch>/u-boot.h,
4257 and make sure that your definition of IMAP_ADDR uses the same value
4258 as your U-Boot configuration in CONFIG_SYS_IMMR.
4261 Configuring the Linux kernel:
4262 -----------------------------
4264 No specific requirements for U-Boot. Make sure you have some root
4265 device (initial ramdisk, NFS) for your target system.
4268 Building a Linux Image:
4269 -----------------------
4271 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4272 not used. If you use recent kernel source, a new build target
4273 "uImage" will exist which automatically builds an image usable by
4274 U-Boot. Most older kernels also have support for a "pImage" target,
4275 which was introduced for our predecessor project PPCBoot and uses a
4276 100% compatible format.
4285 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4286 encapsulate a compressed Linux kernel image with header information,
4287 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4289 * build a standard "vmlinux" kernel image (in ELF binary format):
4291 * convert the kernel into a raw binary image:
4293 ${CROSS_COMPILE}-objcopy -O binary \
4294 -R .note -R .comment \
4295 -S vmlinux linux.bin
4297 * compress the binary image:
4301 * package compressed binary image for U-Boot:
4303 mkimage -A ppc -O linux -T kernel -C gzip \
4304 -a 0 -e 0 -n "Linux Kernel Image" \
4305 -d linux.bin.gz uImage
4308 The "mkimage" tool can also be used to create ramdisk images for use
4309 with U-Boot, either separated from the Linux kernel image, or
4310 combined into one file. "mkimage" encapsulates the images with a 64
4311 byte header containing information about target architecture,
4312 operating system, image type, compression method, entry points, time
4313 stamp, CRC32 checksums, etc.
4315 "mkimage" can be called in two ways: to verify existing images and
4316 print the header information, or to build new images.
4318 In the first form (with "-l" option) mkimage lists the information
4319 contained in the header of an existing U-Boot image; this includes
4320 checksum verification:
4322 tools/mkimage -l image
4323 -l ==> list image header information
4325 The second form (with "-d" option) is used to build a U-Boot image
4326 from a "data file" which is used as image payload:
4328 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4329 -n name -d data_file image
4330 -A ==> set architecture to 'arch'
4331 -O ==> set operating system to 'os'
4332 -T ==> set image type to 'type'
4333 -C ==> set compression type 'comp'
4334 -a ==> set load address to 'addr' (hex)
4335 -e ==> set entry point to 'ep' (hex)
4336 -n ==> set image name to 'name'
4337 -d ==> use image data from 'datafile'
4339 Right now, all Linux kernels for PowerPC systems use the same load
4340 address (0x00000000), but the entry point address depends on the
4343 - 2.2.x kernels have the entry point at 0x0000000C,
4344 - 2.3.x and later kernels have the entry point at 0x00000000.
4346 So a typical call to build a U-Boot image would read:
4348 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4349 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4350 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4351 > examples/uImage.TQM850L
4352 Image Name: 2.4.4 kernel for TQM850L
4353 Created: Wed Jul 19 02:34:59 2000
4354 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4355 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4356 Load Address: 0x00000000
4357 Entry Point: 0x00000000
4359 To verify the contents of the image (or check for corruption):
4361 -> tools/mkimage -l examples/uImage.TQM850L
4362 Image Name: 2.4.4 kernel for TQM850L
4363 Created: Wed Jul 19 02:34:59 2000
4364 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4365 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4366 Load Address: 0x00000000
4367 Entry Point: 0x00000000
4369 NOTE: for embedded systems where boot time is critical you can trade
4370 speed for memory and install an UNCOMPRESSED image instead: this
4371 needs more space in Flash, but boots much faster since it does not
4372 need to be uncompressed:
4374 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4375 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4376 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4377 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4378 > examples/uImage.TQM850L-uncompressed
4379 Image Name: 2.4.4 kernel for TQM850L
4380 Created: Wed Jul 19 02:34:59 2000
4381 Image Type: PowerPC Linux Kernel Image (uncompressed)
4382 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4383 Load Address: 0x00000000
4384 Entry Point: 0x00000000
4387 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4388 when your kernel is intended to use an initial ramdisk:
4390 -> tools/mkimage -n 'Simple Ramdisk Image' \
4391 > -A ppc -O linux -T ramdisk -C gzip \
4392 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4393 Image Name: Simple Ramdisk Image
4394 Created: Wed Jan 12 14:01:50 2000
4395 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4396 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4397 Load Address: 0x00000000
4398 Entry Point: 0x00000000
4401 Installing a Linux Image:
4402 -------------------------
4404 To downloading a U-Boot image over the serial (console) interface,
4405 you must convert the image to S-Record format:
4407 objcopy -I binary -O srec examples/image examples/image.srec
4409 The 'objcopy' does not understand the information in the U-Boot
4410 image header, so the resulting S-Record file will be relative to
4411 address 0x00000000. To load it to a given address, you need to
4412 specify the target address as 'offset' parameter with the 'loads'
4415 Example: install the image to address 0x40100000 (which on the
4416 TQM8xxL is in the first Flash bank):
4418 => erase 40100000 401FFFFF
4424 ## Ready for S-Record download ...
4425 ~>examples/image.srec
4426 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4428 15989 15990 15991 15992
4429 [file transfer complete]
4431 ## Start Addr = 0x00000000
4434 You can check the success of the download using the 'iminfo' command;
4435 this includes a checksum verification so you can be sure no data
4436 corruption happened:
4440 ## Checking Image at 40100000 ...
4441 Image Name: 2.2.13 for initrd on TQM850L
4442 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4443 Data Size: 335725 Bytes = 327 kB = 0 MB
4444 Load Address: 00000000
4445 Entry Point: 0000000c
4446 Verifying Checksum ... OK
4452 The "bootm" command is used to boot an application that is stored in
4453 memory (RAM or Flash). In case of a Linux kernel image, the contents
4454 of the "bootargs" environment variable is passed to the kernel as
4455 parameters. You can check and modify this variable using the
4456 "printenv" and "setenv" commands:
4459 => printenv bootargs
4460 bootargs=root=/dev/ram
4462 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4464 => printenv bootargs
4465 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4468 ## Booting Linux kernel at 40020000 ...
4469 Image Name: 2.2.13 for NFS on TQM850L
4470 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4471 Data Size: 381681 Bytes = 372 kB = 0 MB
4472 Load Address: 00000000
4473 Entry Point: 0000000c
4474 Verifying Checksum ... OK
4475 Uncompressing Kernel Image ... OK
4476 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4477 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4478 time_init: decrementer frequency = 187500000/60
4479 Calibrating delay loop... 49.77 BogoMIPS
4480 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4483 If you want to boot a Linux kernel with initial RAM disk, you pass
4484 the memory addresses of both the kernel and the initrd image (PPBCOOT
4485 format!) to the "bootm" command:
4487 => imi 40100000 40200000
4489 ## Checking Image at 40100000 ...
4490 Image Name: 2.2.13 for initrd on TQM850L
4491 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4492 Data Size: 335725 Bytes = 327 kB = 0 MB
4493 Load Address: 00000000
4494 Entry Point: 0000000c
4495 Verifying Checksum ... OK
4497 ## Checking Image at 40200000 ...
4498 Image Name: Simple Ramdisk Image
4499 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4500 Data Size: 566530 Bytes = 553 kB = 0 MB
4501 Load Address: 00000000
4502 Entry Point: 00000000
4503 Verifying Checksum ... OK
4505 => bootm 40100000 40200000
4506 ## Booting Linux kernel at 40100000 ...
4507 Image Name: 2.2.13 for initrd on TQM850L
4508 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4509 Data Size: 335725 Bytes = 327 kB = 0 MB
4510 Load Address: 00000000
4511 Entry Point: 0000000c
4512 Verifying Checksum ... OK
4513 Uncompressing Kernel Image ... OK
4514 ## Loading RAMDisk Image at 40200000 ...
4515 Image Name: Simple Ramdisk Image
4516 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4517 Data Size: 566530 Bytes = 553 kB = 0 MB
4518 Load Address: 00000000
4519 Entry Point: 00000000
4520 Verifying Checksum ... OK
4521 Loading Ramdisk ... OK
4522 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4523 Boot arguments: root=/dev/ram
4524 time_init: decrementer frequency = 187500000/60
4525 Calibrating delay loop... 49.77 BogoMIPS
4527 RAMDISK: Compressed image found at block 0
4528 VFS: Mounted root (ext2 filesystem).
4532 Boot Linux and pass a flat device tree:
4535 First, U-Boot must be compiled with the appropriate defines. See the section
4536 titled "Linux Kernel Interface" above for a more in depth explanation. The
4537 following is an example of how to start a kernel and pass an updated
4543 oft=oftrees/mpc8540ads.dtb
4544 => tftp $oftaddr $oft
4545 Speed: 1000, full duplex
4547 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4548 Filename 'oftrees/mpc8540ads.dtb'.
4549 Load address: 0x300000
4552 Bytes transferred = 4106 (100a hex)
4553 => tftp $loadaddr $bootfile
4554 Speed: 1000, full duplex
4556 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4558 Load address: 0x200000
4559 Loading:############
4561 Bytes transferred = 1029407 (fb51f hex)
4566 => bootm $loadaddr - $oftaddr
4567 ## Booting image at 00200000 ...
4568 Image Name: Linux-2.6.17-dirty
4569 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4570 Data Size: 1029343 Bytes = 1005.2 kB
4571 Load Address: 00000000
4572 Entry Point: 00000000
4573 Verifying Checksum ... OK
4574 Uncompressing Kernel Image ... OK
4575 Booting using flat device tree at 0x300000
4576 Using MPC85xx ADS machine description
4577 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4581 More About U-Boot Image Types:
4582 ------------------------------
4584 U-Boot supports the following image types:
4586 "Standalone Programs" are directly runnable in the environment
4587 provided by U-Boot; it is expected that (if they behave
4588 well) you can continue to work in U-Boot after return from
4589 the Standalone Program.
4590 "OS Kernel Images" are usually images of some Embedded OS which
4591 will take over control completely. Usually these programs
4592 will install their own set of exception handlers, device
4593 drivers, set up the MMU, etc. - this means, that you cannot
4594 expect to re-enter U-Boot except by resetting the CPU.
4595 "RAMDisk Images" are more or less just data blocks, and their
4596 parameters (address, size) are passed to an OS kernel that is
4598 "Multi-File Images" contain several images, typically an OS
4599 (Linux) kernel image and one or more data images like
4600 RAMDisks. This construct is useful for instance when you want
4601 to boot over the network using BOOTP etc., where the boot
4602 server provides just a single image file, but you want to get
4603 for instance an OS kernel and a RAMDisk image.
4605 "Multi-File Images" start with a list of image sizes, each
4606 image size (in bytes) specified by an "uint32_t" in network
4607 byte order. This list is terminated by an "(uint32_t)0".
4608 Immediately after the terminating 0 follow the images, one by
4609 one, all aligned on "uint32_t" boundaries (size rounded up to
4610 a multiple of 4 bytes).
4612 "Firmware Images" are binary images containing firmware (like
4613 U-Boot or FPGA images) which usually will be programmed to
4616 "Script files" are command sequences that will be executed by
4617 U-Boot's command interpreter; this feature is especially
4618 useful when you configure U-Boot to use a real shell (hush)
4619 as command interpreter.
4621 Booting the Linux zImage:
4622 -------------------------
4624 On some platforms, it's possible to boot Linux zImage. This is done
4625 using the "bootz" command. The syntax of "bootz" command is the same
4626 as the syntax of "bootm" command.
4628 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4629 kernel with raw initrd images. The syntax is slightly different, the
4630 address of the initrd must be augmented by it's size, in the following
4631 format: "<initrd addres>:<initrd size>".
4637 One of the features of U-Boot is that you can dynamically load and
4638 run "standalone" applications, which can use some resources of
4639 U-Boot like console I/O functions or interrupt services.
4641 Two simple examples are included with the sources:
4646 'examples/hello_world.c' contains a small "Hello World" Demo
4647 application; it is automatically compiled when you build U-Boot.
4648 It's configured to run at address 0x00040004, so you can play with it
4652 ## Ready for S-Record download ...
4653 ~>examples/hello_world.srec
4654 1 2 3 4 5 6 7 8 9 10 11 ...
4655 [file transfer complete]
4657 ## Start Addr = 0x00040004
4659 => go 40004 Hello World! This is a test.
4660 ## Starting application at 0x00040004 ...
4671 Hit any key to exit ...
4673 ## Application terminated, rc = 0x0
4675 Another example, which demonstrates how to register a CPM interrupt
4676 handler with the U-Boot code, can be found in 'examples/timer.c'.
4677 Here, a CPM timer is set up to generate an interrupt every second.
4678 The interrupt service routine is trivial, just printing a '.'
4679 character, but this is just a demo program. The application can be
4680 controlled by the following keys:
4682 ? - print current values og the CPM Timer registers
4683 b - enable interrupts and start timer
4684 e - stop timer and disable interrupts
4685 q - quit application
4688 ## Ready for S-Record download ...
4689 ~>examples/timer.srec
4690 1 2 3 4 5 6 7 8 9 10 11 ...
4691 [file transfer complete]
4693 ## Start Addr = 0x00040004
4696 ## Starting application at 0x00040004 ...
4699 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4702 [q, b, e, ?] Set interval 1000000 us
4705 [q, b, e, ?] ........
4706 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4709 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4712 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4715 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4717 [q, b, e, ?] ...Stopping timer
4719 [q, b, e, ?] ## Application terminated, rc = 0x0
4725 Over time, many people have reported problems when trying to use the
4726 "minicom" terminal emulation program for serial download. I (wd)
4727 consider minicom to be broken, and recommend not to use it. Under
4728 Unix, I recommend to use C-Kermit for general purpose use (and
4729 especially for kermit binary protocol download ("loadb" command), and
4730 use "cu" for S-Record download ("loads" command). See
4731 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4732 for help with kermit.
4735 Nevertheless, if you absolutely want to use it try adding this
4736 configuration to your "File transfer protocols" section:
4738 Name Program Name U/D FullScr IO-Red. Multi
4739 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4740 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4746 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4747 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4749 Building requires a cross environment; it is known to work on
4750 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4751 need gmake since the Makefiles are not compatible with BSD make).
4752 Note that the cross-powerpc package does not install include files;
4753 attempting to build U-Boot will fail because <machine/ansi.h> is
4754 missing. This file has to be installed and patched manually:
4756 # cd /usr/pkg/cross/powerpc-netbsd/include
4758 # ln -s powerpc machine
4759 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4760 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4762 Native builds *don't* work due to incompatibilities between native
4763 and U-Boot include files.
4765 Booting assumes that (the first part of) the image booted is a
4766 stage-2 loader which in turn loads and then invokes the kernel
4767 proper. Loader sources will eventually appear in the NetBSD source
4768 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4769 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4772 Implementation Internals:
4773 =========================
4775 The following is not intended to be a complete description of every
4776 implementation detail. However, it should help to understand the
4777 inner workings of U-Boot and make it easier to port it to custom
4781 Initial Stack, Global Data:
4782 ---------------------------
4784 The implementation of U-Boot is complicated by the fact that U-Boot
4785 starts running out of ROM (flash memory), usually without access to
4786 system RAM (because the memory controller is not initialized yet).
4787 This means that we don't have writable Data or BSS segments, and BSS
4788 is not initialized as zero. To be able to get a C environment working
4789 at all, we have to allocate at least a minimal stack. Implementation
4790 options for this are defined and restricted by the CPU used: Some CPU
4791 models provide on-chip memory (like the IMMR area on MPC8xx and
4792 MPC826x processors), on others (parts of) the data cache can be
4793 locked as (mis-) used as memory, etc.
4795 Chris Hallinan posted a good summary of these issues to the
4796 U-Boot mailing list:
4798 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4800 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4803 Correct me if I'm wrong, folks, but the way I understand it
4804 is this: Using DCACHE as initial RAM for Stack, etc, does not
4805 require any physical RAM backing up the cache. The cleverness
4806 is that the cache is being used as a temporary supply of
4807 necessary storage before the SDRAM controller is setup. It's
4808 beyond the scope of this list to explain the details, but you
4809 can see how this works by studying the cache architecture and
4810 operation in the architecture and processor-specific manuals.
4812 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4813 is another option for the system designer to use as an
4814 initial stack/RAM area prior to SDRAM being available. Either
4815 option should work for you. Using CS 4 should be fine if your
4816 board designers haven't used it for something that would
4817 cause you grief during the initial boot! It is frequently not
4820 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4821 with your processor/board/system design. The default value
4822 you will find in any recent u-boot distribution in
4823 walnut.h should work for you. I'd set it to a value larger
4824 than your SDRAM module. If you have a 64MB SDRAM module, set
4825 it above 400_0000. Just make sure your board has no resources
4826 that are supposed to respond to that address! That code in
4827 start.S has been around a while and should work as is when
4828 you get the config right.
4833 It is essential to remember this, since it has some impact on the C
4834 code for the initialization procedures:
4836 * Initialized global data (data segment) is read-only. Do not attempt
4839 * Do not use any uninitialized global data (or implicitely initialized
4840 as zero data - BSS segment) at all - this is undefined, initiali-
4841 zation is performed later (when relocating to RAM).
4843 * Stack space is very limited. Avoid big data buffers or things like
4846 Having only the stack as writable memory limits means we cannot use
4847 normal global data to share information beween the code. But it
4848 turned out that the implementation of U-Boot can be greatly
4849 simplified by making a global data structure (gd_t) available to all
4850 functions. We could pass a pointer to this data as argument to _all_
4851 functions, but this would bloat the code. Instead we use a feature of
4852 the GCC compiler (Global Register Variables) to share the data: we
4853 place a pointer (gd) to the global data into a register which we
4854 reserve for this purpose.
4856 When choosing a register for such a purpose we are restricted by the
4857 relevant (E)ABI specifications for the current architecture, and by
4858 GCC's implementation.
4860 For PowerPC, the following registers have specific use:
4862 R2: reserved for system use
4863 R3-R4: parameter passing and return values
4864 R5-R10: parameter passing
4865 R13: small data area pointer
4869 (U-Boot also uses R12 as internal GOT pointer. r12
4870 is a volatile register so r12 needs to be reset when
4871 going back and forth between asm and C)
4873 ==> U-Boot will use R2 to hold a pointer to the global data
4875 Note: on PPC, we could use a static initializer (since the
4876 address of the global data structure is known at compile time),
4877 but it turned out that reserving a register results in somewhat
4878 smaller code - although the code savings are not that big (on
4879 average for all boards 752 bytes for the whole U-Boot image,
4880 624 text + 127 data).
4882 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4883 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4885 ==> U-Boot will use P3 to hold a pointer to the global data
4887 On ARM, the following registers are used:
4889 R0: function argument word/integer result
4890 R1-R3: function argument word
4892 R10: stack limit (used only if stack checking if enabled)
4893 R11: argument (frame) pointer
4894 R12: temporary workspace
4897 R15: program counter
4899 ==> U-Boot will use R8 to hold a pointer to the global data
4901 On Nios II, the ABI is documented here:
4902 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4904 ==> U-Boot will use gp to hold a pointer to the global data
4906 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4907 to access small data sections, so gp is free.
4909 On NDS32, the following registers are used:
4911 R0-R1: argument/return
4913 R15: temporary register for assembler
4914 R16: trampoline register
4915 R28: frame pointer (FP)
4916 R29: global pointer (GP)
4917 R30: link register (LP)
4918 R31: stack pointer (SP)
4919 PC: program counter (PC)
4921 ==> U-Boot will use R10 to hold a pointer to the global data
4923 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4924 or current versions of GCC may "optimize" the code too much.
4929 U-Boot runs in system state and uses physical addresses, i.e. the
4930 MMU is not used either for address mapping nor for memory protection.
4932 The available memory is mapped to fixed addresses using the memory
4933 controller. In this process, a contiguous block is formed for each
4934 memory type (Flash, SDRAM, SRAM), even when it consists of several
4935 physical memory banks.
4937 U-Boot is installed in the first 128 kB of the first Flash bank (on
4938 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4939 booting and sizing and initializing DRAM, the code relocates itself
4940 to the upper end of DRAM. Immediately below the U-Boot code some
4941 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4942 configuration setting]. Below that, a structure with global Board
4943 Info data is placed, followed by the stack (growing downward).
4945 Additionally, some exception handler code is copied to the low 8 kB
4946 of DRAM (0x00000000 ... 0x00001FFF).
4948 So a typical memory configuration with 16 MB of DRAM could look like
4951 0x0000 0000 Exception Vector code
4954 0x0000 2000 Free for Application Use
4960 0x00FB FF20 Monitor Stack (Growing downward)
4961 0x00FB FFAC Board Info Data and permanent copy of global data
4962 0x00FC 0000 Malloc Arena
4965 0x00FE 0000 RAM Copy of Monitor Code
4966 ... eventually: LCD or video framebuffer
4967 ... eventually: pRAM (Protected RAM - unchanged by reset)
4968 0x00FF FFFF [End of RAM]
4971 System Initialization:
4972 ----------------------
4974 In the reset configuration, U-Boot starts at the reset entry point
4975 (on most PowerPC systems at address 0x00000100). Because of the reset
4976 configuration for CS0# this is a mirror of the onboard Flash memory.
4977 To be able to re-map memory U-Boot then jumps to its link address.
4978 To be able to implement the initialization code in C, a (small!)
4979 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4980 which provide such a feature like MPC8xx or MPC8260), or in a locked
4981 part of the data cache. After that, U-Boot initializes the CPU core,
4982 the caches and the SIU.
4984 Next, all (potentially) available memory banks are mapped using a
4985 preliminary mapping. For example, we put them on 512 MB boundaries
4986 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4987 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4988 programmed for SDRAM access. Using the temporary configuration, a
4989 simple memory test is run that determines the size of the SDRAM
4992 When there is more than one SDRAM bank, and the banks are of
4993 different size, the largest is mapped first. For equal size, the first
4994 bank (CS2#) is mapped first. The first mapping is always for address
4995 0x00000000, with any additional banks following immediately to create
4996 contiguous memory starting from 0.
4998 Then, the monitor installs itself at the upper end of the SDRAM area
4999 and allocates memory for use by malloc() and for the global Board
5000 Info data; also, the exception vector code is copied to the low RAM
5001 pages, and the final stack is set up.
5003 Only after this relocation will you have a "normal" C environment;
5004 until that you are restricted in several ways, mostly because you are
5005 running from ROM, and because the code will have to be relocated to a
5009 U-Boot Porting Guide:
5010 ----------------------
5012 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5016 int main(int argc, char *argv[])
5018 sighandler_t no_more_time;
5020 signal(SIGALRM, no_more_time);
5021 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5023 if (available_money > available_manpower) {
5024 Pay consultant to port U-Boot;
5028 Download latest U-Boot source;
5030 Subscribe to u-boot mailing list;
5033 email("Hi, I am new to U-Boot, how do I get started?");
5036 Read the README file in the top level directory;
5037 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5038 Read applicable doc/*.README;
5039 Read the source, Luke;
5040 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5043 if (available_money > toLocalCurrency ($2500))
5046 Add a lot of aggravation and time;
5048 if (a similar board exists) { /* hopefully... */
5049 cp -a board/<similar> board/<myboard>
5050 cp include/configs/<similar>.h include/configs/<myboard>.h
5052 Create your own board support subdirectory;
5053 Create your own board include/configs/<myboard>.h file;
5055 Edit new board/<myboard> files
5056 Edit new include/configs/<myboard>.h
5061 Add / modify source code;
5065 email("Hi, I am having problems...");
5067 Send patch file to the U-Boot email list;
5068 if (reasonable critiques)
5069 Incorporate improvements from email list code review;
5071 Defend code as written;
5077 void no_more_time (int sig)
5086 All contributions to U-Boot should conform to the Linux kernel
5087 coding style; see the file "Documentation/CodingStyle" and the script
5088 "scripts/Lindent" in your Linux kernel source directory.
5090 Source files originating from a different project (for example the
5091 MTD subsystem) are generally exempt from these guidelines and are not
5092 reformated to ease subsequent migration to newer versions of those
5095 Please note that U-Boot is implemented in C (and to some small parts in
5096 Assembler); no C++ is used, so please do not use C++ style comments (//)
5099 Please also stick to the following formatting rules:
5100 - remove any trailing white space
5101 - use TAB characters for indentation and vertical alignment, not spaces
5102 - make sure NOT to use DOS '\r\n' line feeds
5103 - do not add more than 2 consecutive empty lines to source files
5104 - do not add trailing empty lines to source files
5106 Submissions which do not conform to the standards may be returned
5107 with a request to reformat the changes.
5113 Since the number of patches for U-Boot is growing, we need to
5114 establish some rules. Submissions which do not conform to these rules
5115 may be rejected, even when they contain important and valuable stuff.
5117 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5120 see http://lists.denx.de/mailman/listinfo/u-boot
5122 When you send a patch, please include the following information with
5125 * For bug fixes: a description of the bug and how your patch fixes
5126 this bug. Please try to include a way of demonstrating that the
5127 patch actually fixes something.
5129 * For new features: a description of the feature and your
5132 * A CHANGELOG entry as plaintext (separate from the patch)
5134 * For major contributions, your entry to the CREDITS file
5136 * When you add support for a new board, don't forget to add this
5137 board to the MAINTAINERS file, too.
5139 * If your patch adds new configuration options, don't forget to
5140 document these in the README file.
5142 * The patch itself. If you are using git (which is *strongly*
5143 recommended) you can easily generate the patch using the
5144 "git format-patch". If you then use "git send-email" to send it to
5145 the U-Boot mailing list, you will avoid most of the common problems
5146 with some other mail clients.
5148 If you cannot use git, use "diff -purN OLD NEW". If your version of
5149 diff does not support these options, then get the latest version of
5152 The current directory when running this command shall be the parent
5153 directory of the U-Boot source tree (i. e. please make sure that
5154 your patch includes sufficient directory information for the
5157 We prefer patches as plain text. MIME attachments are discouraged,
5158 and compressed attachments must not be used.
5160 * If one logical set of modifications affects or creates several
5161 files, all these changes shall be submitted in a SINGLE patch file.
5163 * Changesets that contain different, unrelated modifications shall be
5164 submitted as SEPARATE patches, one patch per changeset.
5169 * Before sending the patch, run the MAKEALL script on your patched
5170 source tree and make sure that no errors or warnings are reported
5171 for any of the boards.
5173 * Keep your modifications to the necessary minimum: A patch
5174 containing several unrelated changes or arbitrary reformats will be
5175 returned with a request to re-formatting / split it.
5177 * If you modify existing code, make sure that your new code does not
5178 add to the memory footprint of the code ;-) Small is beautiful!
5179 When adding new features, these should compile conditionally only
5180 (using #ifdef), and the resulting code with the new feature
5181 disabled must not need more memory than the old code without your
5184 * Remember that there is a size limit of 100 kB per message on the
5185 u-boot mailing list. Bigger patches will be moderated. If they are
5186 reasonable and not too big, they will be acknowledged. But patches
5187 bigger than the size limit should be avoided.
projects / u-boot.git / blob