2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /x86 Files generic to x86 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /mips32 Files specific to MIPS32 CPUs
184 /xburst Files specific to Ingenic XBurst CPUs
185 /lib Architecture specific library files
186 /nds32 Files generic to NDS32 architecture
187 /cpu CPU specific files
188 /n1213 Files specific to Andes Technology N1213 CPUs
189 /lib Architecture specific library files
190 /nios2 Files generic to Altera NIOS2 architecture
191 /cpu CPU specific files
192 /lib Architecture specific library files
193 /powerpc Files generic to PowerPC architecture
194 /cpu CPU specific files
195 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
196 /mpc5xx Files specific to Freescale MPC5xx CPUs
197 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
198 /mpc8xx Files specific to Freescale MPC8xx CPUs
199 /mpc8220 Files specific to Freescale MPC8220 CPUs
200 /mpc824x Files specific to Freescale MPC824x CPUs
201 /mpc8260 Files specific to Freescale MPC8260 CPUs
202 /mpc85xx Files specific to Freescale MPC85xx CPUs
203 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
204 /lib Architecture specific library files
205 /sh Files generic to SH architecture
206 /cpu CPU specific files
207 /sh2 Files specific to sh2 CPUs
208 /sh3 Files specific to sh3 CPUs
209 /sh4 Files specific to sh4 CPUs
210 /lib Architecture specific library files
211 /sparc Files generic to SPARC architecture
212 /cpu CPU specific files
213 /leon2 Files specific to Gaisler LEON2 SPARC CPU
214 /leon3 Files specific to Gaisler LEON3 SPARC CPU
215 /lib Architecture specific library files
216 /api Machine/arch independent API for external apps
217 /board Board dependent files
218 /common Misc architecture independent functions
219 /disk Code for disk drive partition handling
220 /doc Documentation (don't expect too much)
221 /drivers Commonly used device drivers
222 /examples Example code for standalone applications, etc.
223 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
224 /include Header Files
225 /lib Files generic to all architectures
226 /libfdt Library files to support flattened device trees
227 /lzma Library files to support LZMA decompression
228 /lzo Library files to support LZO decompression
230 /post Power On Self Test
231 /rtc Real Time Clock drivers
232 /tools Tools to build S-Record or U-Boot images, etc.
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the CPU type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
294 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
296 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
297 Define exactly one, e.g. CONFIG_ATSTK1002
299 - CPU Module Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
302 --- FIXME --- not tested yet:
303 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
304 CONFIG_CMA287_23, CONFIG_CMA287_50
306 - Motherboard Type: (if CONFIG_COGENT is defined)
307 Define exactly one of
308 CONFIG_CMA101, CONFIG_CMA102
310 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
311 Define one or more of
314 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
315 Define one or more of
316 CONFIG_LCD_HEARTBEAT - update a character position on
317 the LCD display every second with
320 - Board flavour: (if CONFIG_MPC8260ADS is defined)
323 CONFIG_SYS_8260ADS - original MPC8260ADS
324 CONFIG_SYS_8266ADS - MPC8266ADS
325 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
326 CONFIG_SYS_8272ADS - MPC8272ADS
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - MPC824X Family Member (if CONFIG_MPC824X is defined)
334 Define exactly one of
335 CONFIG_MPC8240, CONFIG_MPC8245
337 - 8xx CPU Options: (if using an MPC8xx CPU)
338 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
339 get_gclk_freq() cannot work
340 e.g. if there is no 32KHz
341 reference PIT/RTC clock
342 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
345 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
346 CONFIG_SYS_8xx_CPUCLK_MIN
347 CONFIG_SYS_8xx_CPUCLK_MAX
348 CONFIG_8xx_CPUCLK_DEFAULT
349 See doc/README.MPC866
351 CONFIG_SYS_MEASURE_CPUCLK
353 Define this to measure the actual CPU clock instead
354 of relying on the correctness of the configured
355 values. Mostly useful for board bringup to make sure
356 the PLL is locked at the intended frequency. Note
357 that this requires a (stable) reference clock (32 kHz
358 RTC clock or CONFIG_SYS_8XX_XIN)
360 CONFIG_SYS_DELAYED_ICACHE
362 Define this option if you want to enable the
363 ICache only when Code runs from RAM.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_PPC_E500_DEBUG_TLB
379 Enables a temporary TLB entry to be used during boot to work
380 around limitations in e500v1 and e500v2 external debugger
381 support. This reduces the portions of the boot code where
382 breakpoints and single stepping do not work. The value of this
383 symbol should be set to the TLB1 entry to be used for this
386 CONFIG_SYS_FSL_ERRATUM_A004510
388 Enables a workaround for erratum A004510. If set,
389 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
390 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
392 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
393 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
395 Defines one or two SoC revisions (low 8 bits of SVR)
396 for which the A004510 workaround should be applied.
398 The rest of SVR is either not relevant to the decision
399 of whether the erratum is present (e.g. p2040 versus
400 p2041) or is implied by the build target, which controls
401 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
403 See Freescale App Note 4493 for more information about
406 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
408 This is the value to write into CCSR offset 0x18600
409 according to the A004510 workaround.
411 - Generic CPU options:
412 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
414 Defines the endianess of the CPU. Implementation of those
415 values is arch specific.
417 - Intel Monahans options:
418 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
420 Defines the Monahans run mode to oscillator
421 ratio. Valid values are 8, 16, 24, 31. The core
422 frequency is this value multiplied by 13 MHz.
424 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
426 Defines the Monahans turbo mode to oscillator
427 ratio. Valid values are 1 (default if undefined) and
428 2. The core frequency as calculated above is multiplied
432 CONFIG_SYS_INIT_SP_OFFSET
434 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
435 pointer. This is needed for the temporary stack before
438 CONFIG_SYS_MIPS_CACHE_MODE
440 Cache operation mode for the MIPS CPU.
441 See also arch/mips/include/asm/mipsregs.h.
443 CONF_CM_CACHABLE_NO_WA
446 CONF_CM_CACHABLE_NONCOHERENT
450 CONF_CM_CACHABLE_ACCELERATED
452 CONFIG_SYS_XWAY_EBU_BOOTCFG
454 Special option for Lantiq XWAY SoCs for booting from NOR flash.
455 See also arch/mips/cpu/mips32/start.S.
457 CONFIG_XWAY_SWAP_BYTES
459 Enable compilation of tools/xway-swap-bytes needed for Lantiq
460 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
461 be swapped if a flash programmer is used.
464 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
466 Select high exception vectors of the ARM core, e.g., do not
467 clear the V bit of the c1 register of CP15.
469 CONFIG_SYS_THUMB_BUILD
471 Use this flag to build U-Boot using the Thumb instruction
472 set for ARM architectures. Thumb instruction set provides
473 better code density. For ARM architectures that support
474 Thumb2 this flag will result in Thumb2 code generated by
477 - Linux Kernel Interface:
480 U-Boot stores all clock information in Hz
481 internally. For binary compatibility with older Linux
482 kernels (which expect the clocks passed in the
483 bd_info data to be in MHz) the environment variable
484 "clocks_in_mhz" can be defined so that U-Boot
485 converts clock data to MHZ before passing it to the
487 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
488 "clocks_in_mhz=1" is automatically included in the
491 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
493 When transferring memsize parameter to linux, some versions
494 expect it to be in bytes, others in MB.
495 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
499 New kernel versions are expecting firmware settings to be
500 passed using flattened device trees (based on open firmware
504 * New libfdt-based support
505 * Adds the "fdt" command
506 * The bootm command automatically updates the fdt
508 OF_CPU - The proper name of the cpus node (only required for
509 MPC512X and MPC5xxx based boards).
510 OF_SOC - The proper name of the soc node (only required for
511 MPC512X and MPC5xxx based boards).
512 OF_TBCLK - The timebase frequency.
513 OF_STDOUT_PATH - The path to the console device
515 boards with QUICC Engines require OF_QE to set UCC MAC
518 CONFIG_OF_BOARD_SETUP
520 Board code has addition modification that it wants to make
521 to the flat device tree before handing it off to the kernel
525 This define fills in the correct boot CPU in the boot
526 param header, the default value is zero if undefined.
530 U-Boot can detect if an IDE device is present or not.
531 If not, and this new config option is activated, U-Boot
532 removes the ATA node from the DTS before booting Linux,
533 so the Linux IDE driver does not probe the device and
534 crash. This is needed for buggy hardware (uc101) where
535 no pull down resistor is connected to the signal IDE5V_DD7.
537 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
539 This setting is mandatory for all boards that have only one
540 machine type and must be used to specify the machine type
541 number as it appears in the ARM machine registry
542 (see http://www.arm.linux.org.uk/developer/machines/).
543 Only boards that have multiple machine types supported
544 in a single configuration file and the machine type is
545 runtime discoverable, do not have to use this setting.
547 - vxWorks boot parameters:
549 bootvx constructs a valid bootline using the following
550 environments variables: bootfile, ipaddr, serverip, hostname.
551 It loads the vxWorks image pointed bootfile.
553 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
554 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
555 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
556 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
558 CONFIG_SYS_VXWORKS_ADD_PARAMS
560 Add it at the end of the bootline. E.g "u=username pw=secret"
562 Note: If a "bootargs" environment is defined, it will overwride
563 the defaults discussed just above.
565 - Cache Configuration:
566 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
567 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
568 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
570 - Cache Configuration for ARM:
571 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
573 CONFIG_SYS_PL310_BASE - Physical base address of PL310
574 controller register space
579 Define this if you want support for Amba PrimeCell PL010 UARTs.
583 Define this if you want support for Amba PrimeCell PL011 UARTs.
587 If you have Amba PrimeCell PL011 UARTs, set this variable to
588 the clock speed of the UARTs.
592 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
593 define this to a list of base addresses for each (supported)
594 port. See e.g. include/configs/versatile.h
596 CONFIG_PL011_SERIAL_RLCR
598 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
599 have separate receive and transmit line control registers. Set
600 this variable to initialize the extra register.
602 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
604 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
605 boot loader that has already initialized the UART. Define this
606 variable to flush the UART at init time.
610 Depending on board, define exactly one serial port
611 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
612 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
613 console by defining CONFIG_8xx_CONS_NONE
615 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
616 port routines must be defined elsewhere
617 (i.e. serial_init(), serial_getc(), ...)
620 Enables console device for a color framebuffer. Needs following
621 defines (cf. smiLynxEM, i8042)
622 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
624 VIDEO_HW_RECTFILL graphic chip supports
627 VIDEO_HW_BITBLT graphic chip supports
628 bit-blit (cf. smiLynxEM)
629 VIDEO_VISIBLE_COLS visible pixel columns
631 VIDEO_VISIBLE_ROWS visible pixel rows
632 VIDEO_PIXEL_SIZE bytes per pixel
633 VIDEO_DATA_FORMAT graphic data format
634 (0-5, cf. cfb_console.c)
635 VIDEO_FB_ADRS framebuffer address
636 VIDEO_KBD_INIT_FCT keyboard int fct
637 (i.e. i8042_kbd_init())
638 VIDEO_TSTC_FCT test char fct
640 VIDEO_GETC_FCT get char fct
642 CONFIG_CONSOLE_CURSOR cursor drawing on/off
643 (requires blink timer
645 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
646 CONFIG_CONSOLE_TIME display time/date info in
648 (requires CONFIG_CMD_DATE)
649 CONFIG_VIDEO_LOGO display Linux logo in
651 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
652 linux_logo.h for logo.
653 Requires CONFIG_VIDEO_LOGO
654 CONFIG_CONSOLE_EXTRA_INFO
655 additional board info beside
658 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
659 a limited number of ANSI escape sequences (cursor control,
660 erase functions and limited graphics rendition control).
662 When CONFIG_CFB_CONSOLE is defined, video console is
663 default i/o. Serial console can be forced with
664 environment 'console=serial'.
666 When CONFIG_SILENT_CONSOLE is defined, all console
667 messages (by U-Boot and Linux!) can be silenced with
668 the "silent" environment variable. See
669 doc/README.silent for more information.
672 CONFIG_BAUDRATE - in bps
673 Select one of the baudrates listed in
674 CONFIG_SYS_BAUDRATE_TABLE, see below.
675 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
677 - Console Rx buffer length
678 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
679 the maximum receive buffer length for the SMC.
680 This option is actual only for 82xx and 8xx possible.
681 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
682 must be defined, to setup the maximum idle timeout for
685 - Pre-Console Buffer:
686 Prior to the console being initialised (i.e. serial UART
687 initialised etc) all console output is silently discarded.
688 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
689 buffer any console messages prior to the console being
690 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
691 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
692 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
693 bytes are output before the console is initialised, the
694 earlier bytes are discarded.
696 'Sane' compilers will generate smaller code if
697 CONFIG_PRE_CON_BUF_SZ is a power of 2
699 - Safe printf() functions
700 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
701 the printf() functions. These are defined in
702 include/vsprintf.h and include snprintf(), vsnprintf() and
703 so on. Code size increase is approximately 300-500 bytes.
704 If this option is not given then these functions will
705 silently discard their buffer size argument - this means
706 you are not getting any overflow checking in this case.
708 - Boot Delay: CONFIG_BOOTDELAY - in seconds
709 Delay before automatically booting the default image;
710 set to -1 to disable autoboot.
711 set to -2 to autoboot with no delay and not check for abort
712 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
714 See doc/README.autoboot for these options that
715 work with CONFIG_BOOTDELAY. None are required.
716 CONFIG_BOOT_RETRY_TIME
717 CONFIG_BOOT_RETRY_MIN
718 CONFIG_AUTOBOOT_KEYED
719 CONFIG_AUTOBOOT_PROMPT
720 CONFIG_AUTOBOOT_DELAY_STR
721 CONFIG_AUTOBOOT_STOP_STR
722 CONFIG_AUTOBOOT_DELAY_STR2
723 CONFIG_AUTOBOOT_STOP_STR2
724 CONFIG_ZERO_BOOTDELAY_CHECK
725 CONFIG_RESET_TO_RETRY
729 Only needed when CONFIG_BOOTDELAY is enabled;
730 define a command string that is automatically executed
731 when no character is read on the console interface
732 within "Boot Delay" after reset.
735 This can be used to pass arguments to the bootm
736 command. The value of CONFIG_BOOTARGS goes into the
737 environment value "bootargs".
739 CONFIG_RAMBOOT and CONFIG_NFSBOOT
740 The value of these goes into the environment as
741 "ramboot" and "nfsboot" respectively, and can be used
742 as a convenience, when switching between booting from
748 When this option is #defined, the existence of the
749 environment variable "preboot" will be checked
750 immediately before starting the CONFIG_BOOTDELAY
751 countdown and/or running the auto-boot command resp.
752 entering interactive mode.
754 This feature is especially useful when "preboot" is
755 automatically generated or modified. For an example
756 see the LWMON board specific code: here "preboot" is
757 modified when the user holds down a certain
758 combination of keys on the (special) keyboard when
761 - Serial Download Echo Mode:
763 If defined to 1, all characters received during a
764 serial download (using the "loads" command) are
765 echoed back. This might be needed by some terminal
766 emulations (like "cu"), but may as well just take
767 time on others. This setting #define's the initial
768 value of the "loads_echo" environment variable.
770 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
772 Select one of the baudrates listed in
773 CONFIG_SYS_BAUDRATE_TABLE, see below.
776 Monitor commands can be included or excluded
777 from the build by using the #include files
778 <config_cmd_all.h> and #undef'ing unwanted
779 commands, or using <config_cmd_default.h>
780 and augmenting with additional #define's
783 The default command configuration includes all commands
784 except those marked below with a "*".
786 CONFIG_CMD_ASKENV * ask for env variable
787 CONFIG_CMD_BDI bdinfo
788 CONFIG_CMD_BEDBUG * Include BedBug Debugger
789 CONFIG_CMD_BMP * BMP support
790 CONFIG_CMD_BSP * Board specific commands
791 CONFIG_CMD_BOOTD bootd
792 CONFIG_CMD_CACHE * icache, dcache
793 CONFIG_CMD_CONSOLE coninfo
794 CONFIG_CMD_CRC32 * crc32
795 CONFIG_CMD_DATE * support for RTC, date/time...
796 CONFIG_CMD_DHCP * DHCP support
797 CONFIG_CMD_DIAG * Diagnostics
798 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
799 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
800 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
801 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
802 CONFIG_CMD_DTT * Digital Therm and Thermostat
803 CONFIG_CMD_ECHO echo arguments
804 CONFIG_CMD_EDITENV edit env variable
805 CONFIG_CMD_EEPROM * EEPROM read/write support
806 CONFIG_CMD_ELF * bootelf, bootvx
807 CONFIG_CMD_EXPORTENV * export the environment
808 CONFIG_CMD_SAVEENV saveenv
809 CONFIG_CMD_FDC * Floppy Disk Support
810 CONFIG_CMD_FAT * FAT partition support
811 CONFIG_CMD_FDOS * Dos diskette Support
812 CONFIG_CMD_FLASH flinfo, erase, protect
813 CONFIG_CMD_FPGA FPGA device initialization support
814 CONFIG_CMD_GO * the 'go' command (exec code)
815 CONFIG_CMD_GREPENV * search environment
816 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
817 CONFIG_CMD_I2C * I2C serial bus support
818 CONFIG_CMD_IDE * IDE harddisk support
819 CONFIG_CMD_IMI iminfo
820 CONFIG_CMD_IMLS List all found images
821 CONFIG_CMD_IMMAP * IMMR dump support
822 CONFIG_CMD_IMPORTENV * import an environment
823 CONFIG_CMD_INI * import data from an ini file into the env
824 CONFIG_CMD_IRQ * irqinfo
825 CONFIG_CMD_ITEST Integer/string test of 2 values
826 CONFIG_CMD_JFFS2 * JFFS2 Support
827 CONFIG_CMD_KGDB * kgdb
828 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
829 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
831 CONFIG_CMD_LOADB loadb
832 CONFIG_CMD_LOADS loads
833 CONFIG_CMD_MD5SUM print md5 message digest
834 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
835 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
837 CONFIG_CMD_MISC Misc functions like sleep etc
838 CONFIG_CMD_MMC * MMC memory mapped support
839 CONFIG_CMD_MII * MII utility commands
840 CONFIG_CMD_MTDPARTS * MTD partition support
841 CONFIG_CMD_NAND * NAND support
842 CONFIG_CMD_NET bootp, tftpboot, rarpboot
843 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
844 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
845 CONFIG_CMD_PCI * pciinfo
846 CONFIG_CMD_PCMCIA * PCMCIA support
847 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
849 CONFIG_CMD_PORTIO * Port I/O
850 CONFIG_CMD_REGINFO * Register dump
851 CONFIG_CMD_RUN run command in env variable
852 CONFIG_CMD_SAVES * save S record dump
853 CONFIG_CMD_SCSI * SCSI Support
854 CONFIG_CMD_SDRAM * print SDRAM configuration information
855 (requires CONFIG_CMD_I2C)
856 CONFIG_CMD_SETGETDCR Support for DCR Register access
858 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
859 CONFIG_CMD_SHA1SUM print sha1 memory digest
860 (requires CONFIG_CMD_MEMORY)
861 CONFIG_CMD_SOURCE "source" command Support
862 CONFIG_CMD_SPI * SPI serial bus support
863 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
864 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
865 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
866 CONFIG_CMD_TIMER * access to the system tick timer
867 CONFIG_CMD_USB * USB support
868 CONFIG_CMD_CDP * Cisco Discover Protocol support
869 CONFIG_CMD_MFSL * Microblaze FSL support
872 EXAMPLE: If you want all functions except of network
873 support you can write:
875 #include "config_cmd_all.h"
876 #undef CONFIG_CMD_NET
879 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
881 Note: Don't enable the "icache" and "dcache" commands
882 (configuration option CONFIG_CMD_CACHE) unless you know
883 what you (and your U-Boot users) are doing. Data
884 cache cannot be enabled on systems like the 8xx or
885 8260 (where accesses to the IMMR region must be
886 uncached), and it cannot be disabled on all other
887 systems where we (mis-) use the data cache to hold an
888 initial stack and some data.
891 XXX - this list needs to get updated!
895 If this variable is defined, U-Boot will use a device tree
896 to configure its devices, instead of relying on statically
897 compiled #defines in the board file. This option is
898 experimental and only available on a few boards. The device
899 tree is available in the global data as gd->fdt_blob.
901 U-Boot needs to get its device tree from somewhere. This can
902 be done using one of the two options below:
905 If this variable is defined, U-Boot will embed a device tree
906 binary in its image. This device tree file should be in the
907 board directory and called <soc>-<board>.dts. The binary file
908 is then picked up in board_init_f() and made available through
909 the global data structure as gd->blob.
912 If this variable is defined, U-Boot will build a device tree
913 binary. It will be called u-boot.dtb. Architecture-specific
914 code will locate it at run-time. Generally this works by:
916 cat u-boot.bin u-boot.dtb >image.bin
918 and in fact, U-Boot does this for you, creating a file called
919 u-boot-dtb.bin which is useful in the common case. You can
920 still use the individual files if you need something more
925 If this variable is defined, it enables watchdog
926 support for the SoC. There must be support in the SoC
927 specific code for a watchdog. For the 8xx and 8260
928 CPUs, the SIU Watchdog feature is enabled in the SYPCR
929 register. When supported for a specific SoC is
930 available, then no further board specific code should
934 When using a watchdog circuitry external to the used
935 SoC, then define this variable and provide board
936 specific code for the "hw_watchdog_reset" function.
939 CONFIG_VERSION_VARIABLE
940 If this variable is defined, an environment variable
941 named "ver" is created by U-Boot showing the U-Boot
942 version as printed by the "version" command.
943 Any change to this variable will be reverted at the
948 When CONFIG_CMD_DATE is selected, the type of the RTC
949 has to be selected, too. Define exactly one of the
952 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
953 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
954 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
955 CONFIG_RTC_MC146818 - use MC146818 RTC
956 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
957 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
958 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
959 CONFIG_RTC_DS164x - use Dallas DS164x RTC
960 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
961 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
962 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
963 CONFIG_SYS_RV3029_TCR - enable trickle charger on
966 Note that if the RTC uses I2C, then the I2C interface
967 must also be configured. See I2C Support, below.
970 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
971 CONFIG_PCA953X_INFO - enable pca953x info command
973 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
974 chip-ngpio pairs that tell the PCA953X driver the number of
975 pins supported by a particular chip.
977 Note that if the GPIO device uses I2C, then the I2C interface
978 must also be configured. See I2C Support, below.
982 When CONFIG_TIMESTAMP is selected, the timestamp
983 (date and time) of an image is printed by image
984 commands like bootm or iminfo. This option is
985 automatically enabled when you select CONFIG_CMD_DATE .
987 - Partition Labels (disklabels) Supported:
988 Zero or more of the following:
989 CONFIG_MAC_PARTITION Apple's MacOS partition table.
990 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
991 Intel architecture, USB sticks, etc.
992 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
993 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
994 bootloader. Note 2TB partition limit; see
996 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
998 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
999 CONFIG_CMD_SCSI) you must configure support for at
1000 least one non-MTD partition type as well.
1003 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1004 board configurations files but used nowhere!
1006 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1007 be performed by calling the function
1008 ide_set_reset(int reset)
1009 which has to be defined in a board specific file
1014 Set this to enable ATAPI support.
1019 Set this to enable support for disks larger than 137GB
1020 Also look at CONFIG_SYS_64BIT_LBA.
1021 Whithout these , LBA48 support uses 32bit variables and will 'only'
1022 support disks up to 2.1TB.
1024 CONFIG_SYS_64BIT_LBA:
1025 When enabled, makes the IDE subsystem use 64bit sector addresses.
1029 At the moment only there is only support for the
1030 SYM53C8XX SCSI controller; define
1031 CONFIG_SCSI_SYM53C8XX to enable it.
1033 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1034 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1035 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1036 maximum numbers of LUNs, SCSI ID's and target
1038 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1040 - NETWORK Support (PCI):
1042 Support for Intel 8254x/8257x gigabit chips.
1045 Utility code for direct access to the SPI bus on Intel 8257x.
1046 This does not do anything useful unless you set at least one
1047 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1049 CONFIG_E1000_SPI_GENERIC
1050 Allow generic access to the SPI bus on the Intel 8257x, for
1051 example with the "sspi" command.
1054 Management command for E1000 devices. When used on devices
1055 with SPI support you can reprogram the EEPROM from U-Boot.
1057 CONFIG_E1000_FALLBACK_MAC
1058 default MAC for empty EEPROM after production.
1061 Support for Intel 82557/82559/82559ER chips.
1062 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1063 write routine for first time initialisation.
1066 Support for Digital 2114x chips.
1067 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1068 modem chip initialisation (KS8761/QS6611).
1071 Support for National dp83815 chips.
1074 Support for National dp8382[01] gigabit chips.
1076 - NETWORK Support (other):
1078 CONFIG_DRIVER_AT91EMAC
1079 Support for AT91RM9200 EMAC.
1082 Define this to use reduced MII inteface
1084 CONFIG_DRIVER_AT91EMAC_QUIET
1085 If this defined, the driver is quiet.
1086 The driver doen't show link status messages.
1088 CONFIG_CALXEDA_XGMAC
1089 Support for the Calxeda XGMAC device
1091 CONFIG_DRIVER_LAN91C96
1092 Support for SMSC's LAN91C96 chips.
1094 CONFIG_LAN91C96_BASE
1095 Define this to hold the physical address
1096 of the LAN91C96's I/O space
1098 CONFIG_LAN91C96_USE_32_BIT
1099 Define this to enable 32 bit addressing
1101 CONFIG_DRIVER_SMC91111
1102 Support for SMSC's LAN91C111 chip
1104 CONFIG_SMC91111_BASE
1105 Define this to hold the physical address
1106 of the device (I/O space)
1108 CONFIG_SMC_USE_32_BIT
1109 Define this if data bus is 32 bits
1111 CONFIG_SMC_USE_IOFUNCS
1112 Define this to use i/o functions instead of macros
1113 (some hardware wont work with macros)
1115 CONFIG_DRIVER_TI_EMAC
1116 Support for davinci emac
1118 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1119 Define this if you have more then 3 PHYs.
1122 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1124 CONFIG_FTGMAC100_EGIGA
1125 Define this to use GE link update with gigabit PHY.
1126 Define this if FTGMAC100 is connected to gigabit PHY.
1127 If your system has 10/100 PHY only, it might not occur
1128 wrong behavior. Because PHY usually return timeout or
1129 useless data when polling gigabit status and gigabit
1130 control registers. This behavior won't affect the
1131 correctnessof 10/100 link speed update.
1134 Support for SMSC's LAN911x and LAN921x chips
1137 Define this to hold the physical address
1138 of the device (I/O space)
1140 CONFIG_SMC911X_32_BIT
1141 Define this if data bus is 32 bits
1143 CONFIG_SMC911X_16_BIT
1144 Define this if data bus is 16 bits. If your processor
1145 automatically converts one 32 bit word to two 16 bit
1146 words you may also try CONFIG_SMC911X_32_BIT.
1149 Support for Renesas on-chip Ethernet controller
1151 CONFIG_SH_ETHER_USE_PORT
1152 Define the number of ports to be used
1154 CONFIG_SH_ETHER_PHY_ADDR
1155 Define the ETH PHY's address
1157 CONFIG_SH_ETHER_CACHE_WRITEBACK
1158 If this option is set, the driver enables cache flush.
1161 CONFIG_GENERIC_LPC_TPM
1162 Support for generic parallel port TPM devices. Only one device
1163 per system is supported at this time.
1165 CONFIG_TPM_TIS_BASE_ADDRESS
1166 Base address where the generic TPM device is mapped
1167 to. Contemporary x86 systems usually map it at
1171 At the moment only the UHCI host controller is
1172 supported (PIP405, MIP405, MPC5200); define
1173 CONFIG_USB_UHCI to enable it.
1174 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1175 and define CONFIG_USB_STORAGE to enable the USB
1178 Supported are USB Keyboards and USB Floppy drives
1180 MPC5200 USB requires additional defines:
1182 for 528 MHz Clock: 0x0001bbbb
1186 for differential drivers: 0x00001000
1187 for single ended drivers: 0x00005000
1188 for differential drivers on PSC3: 0x00000100
1189 for single ended drivers on PSC3: 0x00004100
1190 CONFIG_SYS_USB_EVENT_POLL
1191 May be defined to allow interrupt polling
1192 instead of using asynchronous interrupts
1194 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1195 txfilltuning field in the EHCI controller on reset.
1198 Define the below if you wish to use the USB console.
1199 Once firmware is rebuilt from a serial console issue the
1200 command "setenv stdin usbtty; setenv stdout usbtty" and
1201 attach your USB cable. The Unix command "dmesg" should print
1202 it has found a new device. The environment variable usbtty
1203 can be set to gserial or cdc_acm to enable your device to
1204 appear to a USB host as a Linux gserial device or a
1205 Common Device Class Abstract Control Model serial device.
1206 If you select usbtty = gserial you should be able to enumerate
1208 # modprobe usbserial vendor=0xVendorID product=0xProductID
1209 else if using cdc_acm, simply setting the environment
1210 variable usbtty to be cdc_acm should suffice. The following
1211 might be defined in YourBoardName.h
1214 Define this to build a UDC device
1217 Define this to have a tty type of device available to
1218 talk to the UDC device
1221 Define this to enable the high speed support for usb
1222 device and usbtty. If this feature is enabled, a routine
1223 int is_usbd_high_speed(void)
1224 also needs to be defined by the driver to dynamically poll
1225 whether the enumeration has succeded at high speed or full
1228 CONFIG_SYS_CONSOLE_IS_IN_ENV
1229 Define this if you want stdin, stdout &/or stderr to
1233 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1234 Derive USB clock from external clock "blah"
1235 - CONFIG_SYS_USB_EXTC_CLK 0x02
1237 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1238 Derive USB clock from brgclk
1239 - CONFIG_SYS_USB_BRG_CLK 0x04
1241 If you have a USB-IF assigned VendorID then you may wish to
1242 define your own vendor specific values either in BoardName.h
1243 or directly in usbd_vendor_info.h. If you don't define
1244 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1245 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1246 should pretend to be a Linux device to it's target host.
1248 CONFIG_USBD_MANUFACTURER
1249 Define this string as the name of your company for
1250 - CONFIG_USBD_MANUFACTURER "my company"
1252 CONFIG_USBD_PRODUCT_NAME
1253 Define this string as the name of your product
1254 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1256 CONFIG_USBD_VENDORID
1257 Define this as your assigned Vendor ID from the USB
1258 Implementors Forum. This *must* be a genuine Vendor ID
1259 to avoid polluting the USB namespace.
1260 - CONFIG_USBD_VENDORID 0xFFFF
1262 CONFIG_USBD_PRODUCTID
1263 Define this as the unique Product ID
1265 - CONFIG_USBD_PRODUCTID 0xFFFF
1267 - ULPI Layer Support:
1268 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1269 the generic ULPI layer. The generic layer accesses the ULPI PHY
1270 via the platform viewport, so you need both the genric layer and
1271 the viewport enabled. Currently only Chipidea/ARC based
1272 viewport is supported.
1273 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1274 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1275 If your ULPI phy needs a different reference clock than the
1276 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1277 the appropriate value in Hz.
1280 The MMC controller on the Intel PXA is supported. To
1281 enable this define CONFIG_MMC. The MMC can be
1282 accessed from the boot prompt by mapping the device
1283 to physical memory similar to flash. Command line is
1284 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1285 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1288 Support for Renesas on-chip MMCIF controller
1290 CONFIG_SH_MMCIF_ADDR
1291 Define the base address of MMCIF registers
1294 Define the clock frequency for MMCIF
1296 - Journaling Flash filesystem support:
1297 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1298 CONFIG_JFFS2_NAND_DEV
1299 Define these for a default partition on a NAND device
1301 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1302 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1303 Define these for a default partition on a NOR device
1305 CONFIG_SYS_JFFS_CUSTOM_PART
1306 Define this to create an own partition. You have to provide a
1307 function struct part_info* jffs2_part_info(int part_num)
1309 If you define only one JFFS2 partition you may also want to
1310 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1311 to disable the command chpart. This is the default when you
1312 have not defined a custom partition
1314 - FAT(File Allocation Table) filesystem write function support:
1317 Define this to enable support for saving memory data as a
1318 file in FAT formatted partition.
1320 This will also enable the command "fatwrite" enabling the
1321 user to write files to FAT.
1326 Define this to enable standard (PC-Style) keyboard
1330 Standard PC keyboard driver with US (is default) and
1331 GERMAN key layout (switch via environment 'keymap=de') support.
1332 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1333 for cfb_console. Supports cursor blinking.
1338 Define this to enable video support (for output to
1341 CONFIG_VIDEO_CT69000
1343 Enable Chips & Technologies 69000 Video chip
1345 CONFIG_VIDEO_SMI_LYNXEM
1346 Enable Silicon Motion SMI 712/710/810 Video chip. The
1347 video output is selected via environment 'videoout'
1348 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1351 For the CT69000 and SMI_LYNXEM drivers, videomode is
1352 selected via environment 'videomode'. Two different ways
1354 - "videomode=num" 'num' is a standard LiLo mode numbers.
1355 Following standard modes are supported (* is default):
1357 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1358 -------------+---------------------------------------------
1359 8 bits | 0x301* 0x303 0x305 0x161 0x307
1360 15 bits | 0x310 0x313 0x316 0x162 0x319
1361 16 bits | 0x311 0x314 0x317 0x163 0x31A
1362 24 bits | 0x312 0x315 0x318 ? 0x31B
1363 -------------+---------------------------------------------
1364 (i.e. setenv videomode 317; saveenv; reset;)
1366 - "videomode=bootargs" all the video parameters are parsed
1367 from the bootargs. (See drivers/video/videomodes.c)
1370 CONFIG_VIDEO_SED13806
1371 Enable Epson SED13806 driver. This driver supports 8bpp
1372 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1373 or CONFIG_VIDEO_SED13806_16BPP
1376 Enable the Freescale DIU video driver. Reference boards for
1377 SOCs that have a DIU should define this macro to enable DIU
1378 support, and should also define these other macros:
1384 CONFIG_VIDEO_SW_CURSOR
1385 CONFIG_VGA_AS_SINGLE_DEVICE
1387 CONFIG_VIDEO_BMP_LOGO
1389 The DIU driver will look for the 'video-mode' environment
1390 variable, and if defined, enable the DIU as a console during
1391 boot. See the documentation file README.video for a
1392 description of this variable.
1397 Define this to enable a custom keyboard support.
1398 This simply calls drv_keyboard_init() which must be
1399 defined in your board-specific files.
1400 The only board using this so far is RBC823.
1402 - LCD Support: CONFIG_LCD
1404 Define this to enable LCD support (for output to LCD
1405 display); also select one of the supported displays
1406 by defining one of these:
1410 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1412 CONFIG_NEC_NL6448AC33:
1414 NEC NL6448AC33-18. Active, color, single scan.
1416 CONFIG_NEC_NL6448BC20
1418 NEC NL6448BC20-08. 6.5", 640x480.
1419 Active, color, single scan.
1421 CONFIG_NEC_NL6448BC33_54
1423 NEC NL6448BC33-54. 10.4", 640x480.
1424 Active, color, single scan.
1428 Sharp 320x240. Active, color, single scan.
1429 It isn't 16x9, and I am not sure what it is.
1431 CONFIG_SHARP_LQ64D341
1433 Sharp LQ64D341 display, 640x480.
1434 Active, color, single scan.
1438 HLD1045 display, 640x480.
1439 Active, color, single scan.
1443 Optrex CBL50840-2 NF-FW 99 22 M5
1445 Hitachi LMG6912RPFC-00T
1449 320x240. Black & white.
1451 Normally display is black on white background; define
1452 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1454 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1456 If this option is set, the environment is checked for
1457 a variable "splashimage". If found, the usual display
1458 of logo, copyright and system information on the LCD
1459 is suppressed and the BMP image at the address
1460 specified in "splashimage" is loaded instead. The
1461 console is redirected to the "nulldev", too. This
1462 allows for a "silent" boot where a splash screen is
1463 loaded very quickly after power-on.
1465 CONFIG_SPLASH_SCREEN_ALIGN
1467 If this option is set the splash image can be freely positioned
1468 on the screen. Environment variable "splashpos" specifies the
1469 position as "x,y". If a positive number is given it is used as
1470 number of pixel from left/top. If a negative number is given it
1471 is used as number of pixel from right/bottom. You can also
1472 specify 'm' for centering the image.
1475 setenv splashpos m,m
1476 => image at center of screen
1478 setenv splashpos 30,20
1479 => image at x = 30 and y = 20
1481 setenv splashpos -10,m
1482 => vertically centered image
1483 at x = dspWidth - bmpWidth - 9
1485 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1487 If this option is set, additionally to standard BMP
1488 images, gzipped BMP images can be displayed via the
1489 splashscreen support or the bmp command.
1491 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1493 If this option is set, 8-bit RLE compressed BMP images
1494 can be displayed via the splashscreen support or the
1497 - Do compresssing for memory range:
1500 If this option is set, it would use zlib deflate method
1501 to compress the specified memory at its best effort.
1503 - Compression support:
1506 If this option is set, support for bzip2 compressed
1507 images is included. If not, only uncompressed and gzip
1508 compressed images are supported.
1510 NOTE: the bzip2 algorithm requires a lot of RAM, so
1511 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1516 If this option is set, support for lzma compressed
1519 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1520 requires an amount of dynamic memory that is given by the
1523 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1525 Where lc and lp stand for, respectively, Literal context bits
1526 and Literal pos bits.
1528 This value is upper-bounded by 14MB in the worst case. Anyway,
1529 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1530 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1531 a very small buffer.
1533 Use the lzmainfo tool to determinate the lc and lp values and
1534 then calculate the amount of needed dynamic memory (ensuring
1535 the appropriate CONFIG_SYS_MALLOC_LEN value).
1540 The address of PHY on MII bus.
1542 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1544 The clock frequency of the MII bus
1548 If this option is set, support for speed/duplex
1549 detection of gigabit PHY is included.
1551 CONFIG_PHY_RESET_DELAY
1553 Some PHY like Intel LXT971A need extra delay after
1554 reset before any MII register access is possible.
1555 For such PHY, set this option to the usec delay
1556 required. (minimum 300usec for LXT971A)
1558 CONFIG_PHY_CMD_DELAY (ppc4xx)
1560 Some PHY like Intel LXT971A need extra delay after
1561 command issued before MII status register can be read
1571 Define a default value for Ethernet address to use
1572 for the respective Ethernet interface, in case this
1573 is not determined automatically.
1578 Define a default value for the IP address to use for
1579 the default Ethernet interface, in case this is not
1580 determined through e.g. bootp.
1581 (Environment variable "ipaddr")
1583 - Server IP address:
1586 Defines a default value for the IP address of a TFTP
1587 server to contact when using the "tftboot" command.
1588 (Environment variable "serverip")
1590 CONFIG_KEEP_SERVERADDR
1592 Keeps the server's MAC address, in the env 'serveraddr'
1593 for passing to bootargs (like Linux's netconsole option)
1595 - Gateway IP address:
1598 Defines a default value for the IP address of the
1599 default router where packets to other networks are
1601 (Environment variable "gatewayip")
1606 Defines a default value for the subnet mask (or
1607 routing prefix) which is used to determine if an IP
1608 address belongs to the local subnet or needs to be
1609 forwarded through a router.
1610 (Environment variable "netmask")
1612 - Multicast TFTP Mode:
1615 Defines whether you want to support multicast TFTP as per
1616 rfc-2090; for example to work with atftp. Lets lots of targets
1617 tftp down the same boot image concurrently. Note: the Ethernet
1618 driver in use must provide a function: mcast() to join/leave a
1621 - BOOTP Recovery Mode:
1622 CONFIG_BOOTP_RANDOM_DELAY
1624 If you have many targets in a network that try to
1625 boot using BOOTP, you may want to avoid that all
1626 systems send out BOOTP requests at precisely the same
1627 moment (which would happen for instance at recovery
1628 from a power failure, when all systems will try to
1629 boot, thus flooding the BOOTP server. Defining
1630 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1631 inserted before sending out BOOTP requests. The
1632 following delays are inserted then:
1634 1st BOOTP request: delay 0 ... 1 sec
1635 2nd BOOTP request: delay 0 ... 2 sec
1636 3rd BOOTP request: delay 0 ... 4 sec
1638 BOOTP requests: delay 0 ... 8 sec
1640 - DHCP Advanced Options:
1641 You can fine tune the DHCP functionality by defining
1642 CONFIG_BOOTP_* symbols:
1644 CONFIG_BOOTP_SUBNETMASK
1645 CONFIG_BOOTP_GATEWAY
1646 CONFIG_BOOTP_HOSTNAME
1647 CONFIG_BOOTP_NISDOMAIN
1648 CONFIG_BOOTP_BOOTPATH
1649 CONFIG_BOOTP_BOOTFILESIZE
1652 CONFIG_BOOTP_SEND_HOSTNAME
1653 CONFIG_BOOTP_NTPSERVER
1654 CONFIG_BOOTP_TIMEOFFSET
1655 CONFIG_BOOTP_VENDOREX
1656 CONFIG_BOOTP_MAY_FAIL
1658 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1659 environment variable, not the BOOTP server.
1661 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1662 after the configured retry count, the call will fail
1663 instead of starting over. This can be used to fail over
1664 to Link-local IP address configuration if the DHCP server
1667 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1668 serverip from a DHCP server, it is possible that more
1669 than one DNS serverip is offered to the client.
1670 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1671 serverip will be stored in the additional environment
1672 variable "dnsip2". The first DNS serverip is always
1673 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1676 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1677 to do a dynamic update of a DNS server. To do this, they
1678 need the hostname of the DHCP requester.
1679 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1680 of the "hostname" environment variable is passed as
1681 option 12 to the DHCP server.
1683 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1685 A 32bit value in microseconds for a delay between
1686 receiving a "DHCP Offer" and sending the "DHCP Request".
1687 This fixes a problem with certain DHCP servers that don't
1688 respond 100% of the time to a "DHCP request". E.g. On an
1689 AT91RM9200 processor running at 180MHz, this delay needed
1690 to be *at least* 15,000 usec before a Windows Server 2003
1691 DHCP server would reply 100% of the time. I recommend at
1692 least 50,000 usec to be safe. The alternative is to hope
1693 that one of the retries will be successful but note that
1694 the DHCP timeout and retry process takes a longer than
1697 - Link-local IP address negotiation:
1698 Negotiate with other link-local clients on the local network
1699 for an address that doesn't require explicit configuration.
1700 This is especially useful if a DHCP server cannot be guaranteed
1701 to exist in all environments that the device must operate.
1703 See doc/README.link-local for more information.
1706 CONFIG_CDP_DEVICE_ID
1708 The device id used in CDP trigger frames.
1710 CONFIG_CDP_DEVICE_ID_PREFIX
1712 A two character string which is prefixed to the MAC address
1717 A printf format string which contains the ascii name of
1718 the port. Normally is set to "eth%d" which sets
1719 eth0 for the first Ethernet, eth1 for the second etc.
1721 CONFIG_CDP_CAPABILITIES
1723 A 32bit integer which indicates the device capabilities;
1724 0x00000010 for a normal host which does not forwards.
1728 An ascii string containing the version of the software.
1732 An ascii string containing the name of the platform.
1736 A 32bit integer sent on the trigger.
1738 CONFIG_CDP_POWER_CONSUMPTION
1740 A 16bit integer containing the power consumption of the
1741 device in .1 of milliwatts.
1743 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1745 A byte containing the id of the VLAN.
1747 - Status LED: CONFIG_STATUS_LED
1749 Several configurations allow to display the current
1750 status using a LED. For instance, the LED will blink
1751 fast while running U-Boot code, stop blinking as
1752 soon as a reply to a BOOTP request was received, and
1753 start blinking slow once the Linux kernel is running
1754 (supported by a status LED driver in the Linux
1755 kernel). Defining CONFIG_STATUS_LED enables this
1758 - CAN Support: CONFIG_CAN_DRIVER
1760 Defining CONFIG_CAN_DRIVER enables CAN driver support
1761 on those systems that support this (optional)
1762 feature, like the TQM8xxL modules.
1764 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1766 These enable I2C serial bus commands. Defining either of
1767 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1768 include the appropriate I2C driver for the selected CPU.
1770 This will allow you to use i2c commands at the u-boot
1771 command line (as long as you set CONFIG_CMD_I2C in
1772 CONFIG_COMMANDS) and communicate with i2c based realtime
1773 clock chips. See common/cmd_i2c.c for a description of the
1774 command line interface.
1776 CONFIG_HARD_I2C selects a hardware I2C controller.
1778 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1779 bit-banging) driver instead of CPM or similar hardware
1782 There are several other quantities that must also be
1783 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1785 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1786 to be the frequency (in Hz) at which you wish your i2c bus
1787 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1788 the CPU's i2c node address).
1790 Now, the u-boot i2c code for the mpc8xx
1791 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1792 and so its address should therefore be cleared to 0 (See,
1793 eg, MPC823e User's Manual p.16-473). So, set
1794 CONFIG_SYS_I2C_SLAVE to 0.
1796 CONFIG_SYS_I2C_INIT_MPC5XXX
1798 When a board is reset during an i2c bus transfer
1799 chips might think that the current transfer is still
1800 in progress. Reset the slave devices by sending start
1801 commands until the slave device responds.
1803 That's all that's required for CONFIG_HARD_I2C.
1805 If you use the software i2c interface (CONFIG_SOFT_I2C)
1806 then the following macros need to be defined (examples are
1807 from include/configs/lwmon.h):
1811 (Optional). Any commands necessary to enable the I2C
1812 controller or configure ports.
1814 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1818 (Only for MPC8260 CPU). The I/O port to use (the code
1819 assumes both bits are on the same port). Valid values
1820 are 0..3 for ports A..D.
1824 The code necessary to make the I2C data line active
1825 (driven). If the data line is open collector, this
1828 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1832 The code necessary to make the I2C data line tri-stated
1833 (inactive). If the data line is open collector, this
1836 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1840 Code that returns TRUE if the I2C data line is high,
1843 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1847 If <bit> is TRUE, sets the I2C data line high. If it
1848 is FALSE, it clears it (low).
1850 eg: #define I2C_SDA(bit) \
1851 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1852 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1856 If <bit> is TRUE, sets the I2C clock line high. If it
1857 is FALSE, it clears it (low).
1859 eg: #define I2C_SCL(bit) \
1860 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1861 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1865 This delay is invoked four times per clock cycle so this
1866 controls the rate of data transfer. The data rate thus
1867 is 1 / (I2C_DELAY * 4). Often defined to be something
1870 #define I2C_DELAY udelay(2)
1872 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1874 If your arch supports the generic GPIO framework (asm/gpio.h),
1875 then you may alternatively define the two GPIOs that are to be
1876 used as SCL / SDA. Any of the previous I2C_xxx macros will
1877 have GPIO-based defaults assigned to them as appropriate.
1879 You should define these to the GPIO value as given directly to
1880 the generic GPIO functions.
1882 CONFIG_SYS_I2C_INIT_BOARD
1884 When a board is reset during an i2c bus transfer
1885 chips might think that the current transfer is still
1886 in progress. On some boards it is possible to access
1887 the i2c SCLK line directly, either by using the
1888 processor pin as a GPIO or by having a second pin
1889 connected to the bus. If this option is defined a
1890 custom i2c_init_board() routine in boards/xxx/board.c
1891 is run early in the boot sequence.
1893 CONFIG_SYS_I2C_BOARD_LATE_INIT
1895 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1896 defined a custom i2c_board_late_init() routine in
1897 boards/xxx/board.c is run AFTER the operations in i2c_init()
1898 is completed. This callpoint can be used to unreset i2c bus
1899 using CPU i2c controller register accesses for CPUs whose i2c
1900 controller provide such a method. It is called at the end of
1901 i2c_init() to allow i2c_init operations to setup the i2c bus
1902 controller on the CPU (e.g. setting bus speed & slave address).
1904 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1906 This option enables configuration of bi_iic_fast[] flags
1907 in u-boot bd_info structure based on u-boot environment
1908 variable "i2cfast". (see also i2cfast)
1910 CONFIG_I2C_MULTI_BUS
1912 This option allows the use of multiple I2C buses, each of which
1913 must have a controller. At any point in time, only one bus is
1914 active. To switch to a different bus, use the 'i2c dev' command.
1915 Note that bus numbering is zero-based.
1917 CONFIG_SYS_I2C_NOPROBES
1919 This option specifies a list of I2C devices that will be skipped
1920 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1921 is set, specify a list of bus-device pairs. Otherwise, specify
1922 a 1D array of device addresses
1925 #undef CONFIG_I2C_MULTI_BUS
1926 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1928 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1930 #define CONFIG_I2C_MULTI_BUS
1931 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1933 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1935 CONFIG_SYS_SPD_BUS_NUM
1937 If defined, then this indicates the I2C bus number for DDR SPD.
1938 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1940 CONFIG_SYS_RTC_BUS_NUM
1942 If defined, then this indicates the I2C bus number for the RTC.
1943 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1945 CONFIG_SYS_DTT_BUS_NUM
1947 If defined, then this indicates the I2C bus number for the DTT.
1948 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1950 CONFIG_SYS_I2C_DTT_ADDR:
1952 If defined, specifies the I2C address of the DTT device.
1953 If not defined, then U-Boot uses predefined value for
1954 specified DTT device.
1958 Define this option if you want to use Freescale's I2C driver in
1959 drivers/i2c/fsl_i2c.c.
1963 Define this option if you have I2C devices reached over 1 .. n
1964 I2C Muxes like the pca9544a. This option addes a new I2C
1965 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1966 new I2C Bus to the existing I2C Busses. If you select the
1967 new Bus with "i2c dev", u-bbot sends first the commandos for
1968 the muxes to activate this new "bus".
1970 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1974 Adding a new I2C Bus reached over 2 pca9544a muxes
1975 The First mux with address 70 and channel 6
1976 The Second mux with address 71 and channel 4
1978 => i2c bus pca9544a:70:6:pca9544a:71:4
1980 Use the "i2c bus" command without parameter, to get a list
1981 of I2C Busses with muxes:
1984 Busses reached over muxes:
1986 reached over Mux(es):
1989 reached over Mux(es):
1994 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1995 u-boot first sends the command to the mux@70 to enable
1996 channel 6, and then the command to the mux@71 to enable
1999 After that, you can use the "normal" i2c commands as
2000 usual to communicate with your I2C devices behind
2003 This option is actually implemented for the bitbanging
2004 algorithm in common/soft_i2c.c and for the Hardware I2C
2005 Bus on the MPC8260. But it should be not so difficult
2006 to add this option to other architectures.
2008 CONFIG_SOFT_I2C_READ_REPEATED_START
2010 defining this will force the i2c_read() function in
2011 the soft_i2c driver to perform an I2C repeated start
2012 between writing the address pointer and reading the
2013 data. If this define is omitted the default behaviour
2014 of doing a stop-start sequence will be used. Most I2C
2015 devices can use either method, but some require one or
2018 - SPI Support: CONFIG_SPI
2020 Enables SPI driver (so far only tested with
2021 SPI EEPROM, also an instance works with Crystal A/D and
2022 D/As on the SACSng board)
2026 Enables the driver for SPI controller on SuperH. Currently
2027 only SH7757 is supported.
2031 Enables extended (16-bit) SPI EEPROM addressing.
2032 (symmetrical to CONFIG_I2C_X)
2036 Enables a software (bit-bang) SPI driver rather than
2037 using hardware support. This is a general purpose
2038 driver that only requires three general I/O port pins
2039 (two outputs, one input) to function. If this is
2040 defined, the board configuration must define several
2041 SPI configuration items (port pins to use, etc). For
2042 an example, see include/configs/sacsng.h.
2046 Enables a hardware SPI driver for general-purpose reads
2047 and writes. As with CONFIG_SOFT_SPI, the board configuration
2048 must define a list of chip-select function pointers.
2049 Currently supported on some MPC8xxx processors. For an
2050 example, see include/configs/mpc8349emds.h.
2054 Enables the driver for the SPI controllers on i.MX and MXC
2055 SoCs. Currently i.MX31/35/51 are supported.
2057 - FPGA Support: CONFIG_FPGA
2059 Enables FPGA subsystem.
2061 CONFIG_FPGA_<vendor>
2063 Enables support for specific chip vendors.
2066 CONFIG_FPGA_<family>
2068 Enables support for FPGA family.
2069 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2073 Specify the number of FPGA devices to support.
2075 CONFIG_SYS_FPGA_PROG_FEEDBACK
2077 Enable printing of hash marks during FPGA configuration.
2079 CONFIG_SYS_FPGA_CHECK_BUSY
2081 Enable checks on FPGA configuration interface busy
2082 status by the configuration function. This option
2083 will require a board or device specific function to
2088 If defined, a function that provides delays in the FPGA
2089 configuration driver.
2091 CONFIG_SYS_FPGA_CHECK_CTRLC
2092 Allow Control-C to interrupt FPGA configuration
2094 CONFIG_SYS_FPGA_CHECK_ERROR
2096 Check for configuration errors during FPGA bitfile
2097 loading. For example, abort during Virtex II
2098 configuration if the INIT_B line goes low (which
2099 indicated a CRC error).
2101 CONFIG_SYS_FPGA_WAIT_INIT
2103 Maximum time to wait for the INIT_B line to deassert
2104 after PROB_B has been deasserted during a Virtex II
2105 FPGA configuration sequence. The default time is 500
2108 CONFIG_SYS_FPGA_WAIT_BUSY
2110 Maximum time to wait for BUSY to deassert during
2111 Virtex II FPGA configuration. The default is 5 ms.
2113 CONFIG_SYS_FPGA_WAIT_CONFIG
2115 Time to wait after FPGA configuration. The default is
2118 - Configuration Management:
2121 If defined, this string will be added to the U-Boot
2122 version information (U_BOOT_VERSION)
2124 - Vendor Parameter Protection:
2126 U-Boot considers the values of the environment
2127 variables "serial#" (Board Serial Number) and
2128 "ethaddr" (Ethernet Address) to be parameters that
2129 are set once by the board vendor / manufacturer, and
2130 protects these variables from casual modification by
2131 the user. Once set, these variables are read-only,
2132 and write or delete attempts are rejected. You can
2133 change this behaviour:
2135 If CONFIG_ENV_OVERWRITE is #defined in your config
2136 file, the write protection for vendor parameters is
2137 completely disabled. Anybody can change or delete
2140 Alternatively, if you #define _both_ CONFIG_ETHADDR
2141 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2142 Ethernet address is installed in the environment,
2143 which can be changed exactly ONCE by the user. [The
2144 serial# is unaffected by this, i. e. it remains
2150 Define this variable to enable the reservation of
2151 "protected RAM", i. e. RAM which is not overwritten
2152 by U-Boot. Define CONFIG_PRAM to hold the number of
2153 kB you want to reserve for pRAM. You can overwrite
2154 this default value by defining an environment
2155 variable "pram" to the number of kB you want to
2156 reserve. Note that the board info structure will
2157 still show the full amount of RAM. If pRAM is
2158 reserved, a new environment variable "mem" will
2159 automatically be defined to hold the amount of
2160 remaining RAM in a form that can be passed as boot
2161 argument to Linux, for instance like that:
2163 setenv bootargs ... mem=\${mem}
2166 This way you can tell Linux not to use this memory,
2167 either, which results in a memory region that will
2168 not be affected by reboots.
2170 *WARNING* If your board configuration uses automatic
2171 detection of the RAM size, you must make sure that
2172 this memory test is non-destructive. So far, the
2173 following board configurations are known to be
2176 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2177 HERMES, IP860, RPXlite, LWMON, LANTEC,
2183 Define this variable to stop the system in case of a
2184 fatal error, so that you have to reset it manually.
2185 This is probably NOT a good idea for an embedded
2186 system where you want the system to reboot
2187 automatically as fast as possible, but it may be
2188 useful during development since you can try to debug
2189 the conditions that lead to the situation.
2191 CONFIG_NET_RETRY_COUNT
2193 This variable defines the number of retries for
2194 network operations like ARP, RARP, TFTP, or BOOTP
2195 before giving up the operation. If not defined, a
2196 default value of 5 is used.
2200 Timeout waiting for an ARP reply in milliseconds.
2204 Timeout in milliseconds used in NFS protocol.
2205 If you encounter "ERROR: Cannot umount" in nfs command,
2206 try longer timeout such as
2207 #define CONFIG_NFS_TIMEOUT 10000UL
2209 - Command Interpreter:
2210 CONFIG_AUTO_COMPLETE
2212 Enable auto completion of commands using TAB.
2214 Note that this feature has NOT been implemented yet
2215 for the "hush" shell.
2218 CONFIG_SYS_HUSH_PARSER
2220 Define this variable to enable the "hush" shell (from
2221 Busybox) as command line interpreter, thus enabling
2222 powerful command line syntax like
2223 if...then...else...fi conditionals or `&&' and '||'
2224 constructs ("shell scripts").
2226 If undefined, you get the old, much simpler behaviour
2227 with a somewhat smaller memory footprint.
2230 CONFIG_SYS_PROMPT_HUSH_PS2
2232 This defines the secondary prompt string, which is
2233 printed when the command interpreter needs more input
2234 to complete a command. Usually "> ".
2238 In the current implementation, the local variables
2239 space and global environment variables space are
2240 separated. Local variables are those you define by
2241 simply typing `name=value'. To access a local
2242 variable later on, you have write `$name' or
2243 `${name}'; to execute the contents of a variable
2244 directly type `$name' at the command prompt.
2246 Global environment variables are those you use
2247 setenv/printenv to work with. To run a command stored
2248 in such a variable, you need to use the run command,
2249 and you must not use the '$' sign to access them.
2251 To store commands and special characters in a
2252 variable, please use double quotation marks
2253 surrounding the whole text of the variable, instead
2254 of the backslashes before semicolons and special
2257 - Commandline Editing and History:
2258 CONFIG_CMDLINE_EDITING
2260 Enable editing and History functions for interactive
2261 commandline input operations
2263 - Default Environment:
2264 CONFIG_EXTRA_ENV_SETTINGS
2266 Define this to contain any number of null terminated
2267 strings (variable = value pairs) that will be part of
2268 the default environment compiled into the boot image.
2270 For example, place something like this in your
2271 board's config file:
2273 #define CONFIG_EXTRA_ENV_SETTINGS \
2277 Warning: This method is based on knowledge about the
2278 internal format how the environment is stored by the
2279 U-Boot code. This is NOT an official, exported
2280 interface! Although it is unlikely that this format
2281 will change soon, there is no guarantee either.
2282 You better know what you are doing here.
2284 Note: overly (ab)use of the default environment is
2285 discouraged. Make sure to check other ways to preset
2286 the environment like the "source" command or the
2289 CONFIG_ENV_VARS_UBOOT_CONFIG
2291 Define this in order to add variables describing the
2292 U-Boot build configuration to the default environment.
2293 These will be named arch, cpu, board, vendor, and soc.
2295 Enabling this option will cause the following to be defined:
2303 - DataFlash Support:
2304 CONFIG_HAS_DATAFLASH
2306 Defining this option enables DataFlash features and
2307 allows to read/write in Dataflash via the standard
2310 - Serial Flash support
2313 Defining this option enables SPI flash commands
2314 'sf probe/read/write/erase/update'.
2316 Usage requires an initial 'probe' to define the serial
2317 flash parameters, followed by read/write/erase/update
2320 The following defaults may be provided by the platform
2321 to handle the common case when only a single serial
2322 flash is present on the system.
2324 CONFIG_SF_DEFAULT_BUS Bus identifier
2325 CONFIG_SF_DEFAULT_CS Chip-select
2326 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2327 CONFIG_SF_DEFAULT_SPEED in Hz
2329 - SystemACE Support:
2332 Adding this option adds support for Xilinx SystemACE
2333 chips attached via some sort of local bus. The address
2334 of the chip must also be defined in the
2335 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2337 #define CONFIG_SYSTEMACE
2338 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2340 When SystemACE support is added, the "ace" device type
2341 becomes available to the fat commands, i.e. fatls.
2343 - TFTP Fixed UDP Port:
2346 If this is defined, the environment variable tftpsrcp
2347 is used to supply the TFTP UDP source port value.
2348 If tftpsrcp isn't defined, the normal pseudo-random port
2349 number generator is used.
2351 Also, the environment variable tftpdstp is used to supply
2352 the TFTP UDP destination port value. If tftpdstp isn't
2353 defined, the normal port 69 is used.
2355 The purpose for tftpsrcp is to allow a TFTP server to
2356 blindly start the TFTP transfer using the pre-configured
2357 target IP address and UDP port. This has the effect of
2358 "punching through" the (Windows XP) firewall, allowing
2359 the remainder of the TFTP transfer to proceed normally.
2360 A better solution is to properly configure the firewall,
2361 but sometimes that is not allowed.
2363 - Show boot progress:
2364 CONFIG_SHOW_BOOT_PROGRESS
2366 Defining this option allows to add some board-
2367 specific code (calling a user-provided function
2368 "show_boot_progress(int)") that enables you to show
2369 the system's boot progress on some display (for
2370 example, some LED's) on your board. At the moment,
2371 the following checkpoints are implemented:
2373 - Detailed boot stage timing
2375 Define this option to get detailed timing of each stage
2376 of the boot process.
2378 CONFIG_BOOTSTAGE_USER_COUNT
2379 This is the number of available user bootstage records.
2380 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2381 a new ID will be allocated from this stash. If you exceed
2382 the limit, recording will stop.
2384 CONFIG_BOOTSTAGE_REPORT
2385 Define this to print a report before boot, similar to this:
2387 Timer summary in microseconds:
2390 3,575,678 3,575,678 board_init_f start
2391 3,575,695 17 arch_cpu_init A9
2392 3,575,777 82 arch_cpu_init done
2393 3,659,598 83,821 board_init_r start
2394 3,910,375 250,777 main_loop
2395 29,916,167 26,005,792 bootm_start
2396 30,361,327 445,160 start_kernel
2398 CONFIG_CMD_BOOTSTAGE
2399 Add a 'bootstage' command which supports printing a report
2400 and un/stashing of bootstage data.
2402 CONFIG_BOOTSTAGE_FDT
2403 Stash the bootstage information in the FDT. A root 'bootstage'
2404 node is created with each bootstage id as a child. Each child
2405 has a 'name' property and either 'mark' containing the
2406 mark time in microsecond, or 'accum' containing the
2407 accumulated time for that bootstage id in microseconds.
2412 name = "board_init_f";
2421 Code in the Linux kernel can find this in /proc/devicetree.
2423 Legacy uImage format:
2426 1 common/cmd_bootm.c before attempting to boot an image
2427 -1 common/cmd_bootm.c Image header has bad magic number
2428 2 common/cmd_bootm.c Image header has correct magic number
2429 -2 common/cmd_bootm.c Image header has bad checksum
2430 3 common/cmd_bootm.c Image header has correct checksum
2431 -3 common/cmd_bootm.c Image data has bad checksum
2432 4 common/cmd_bootm.c Image data has correct checksum
2433 -4 common/cmd_bootm.c Image is for unsupported architecture
2434 5 common/cmd_bootm.c Architecture check OK
2435 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2436 6 common/cmd_bootm.c Image Type check OK
2437 -6 common/cmd_bootm.c gunzip uncompression error
2438 -7 common/cmd_bootm.c Unimplemented compression type
2439 7 common/cmd_bootm.c Uncompression OK
2440 8 common/cmd_bootm.c No uncompress/copy overwrite error
2441 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2443 9 common/image.c Start initial ramdisk verification
2444 -10 common/image.c Ramdisk header has bad magic number
2445 -11 common/image.c Ramdisk header has bad checksum
2446 10 common/image.c Ramdisk header is OK
2447 -12 common/image.c Ramdisk data has bad checksum
2448 11 common/image.c Ramdisk data has correct checksum
2449 12 common/image.c Ramdisk verification complete, start loading
2450 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2451 13 common/image.c Start multifile image verification
2452 14 common/image.c No initial ramdisk, no multifile, continue.
2454 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2456 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2457 -31 post/post.c POST test failed, detected by post_output_backlog()
2458 -32 post/post.c POST test failed, detected by post_run_single()
2460 34 common/cmd_doc.c before loading a Image from a DOC device
2461 -35 common/cmd_doc.c Bad usage of "doc" command
2462 35 common/cmd_doc.c correct usage of "doc" command
2463 -36 common/cmd_doc.c No boot device
2464 36 common/cmd_doc.c correct boot device
2465 -37 common/cmd_doc.c Unknown Chip ID on boot device
2466 37 common/cmd_doc.c correct chip ID found, device available
2467 -38 common/cmd_doc.c Read Error on boot device
2468 38 common/cmd_doc.c reading Image header from DOC device OK
2469 -39 common/cmd_doc.c Image header has bad magic number
2470 39 common/cmd_doc.c Image header has correct magic number
2471 -40 common/cmd_doc.c Error reading Image from DOC device
2472 40 common/cmd_doc.c Image header has correct magic number
2473 41 common/cmd_ide.c before loading a Image from a IDE device
2474 -42 common/cmd_ide.c Bad usage of "ide" command
2475 42 common/cmd_ide.c correct usage of "ide" command
2476 -43 common/cmd_ide.c No boot device
2477 43 common/cmd_ide.c boot device found
2478 -44 common/cmd_ide.c Device not available
2479 44 common/cmd_ide.c Device available
2480 -45 common/cmd_ide.c wrong partition selected
2481 45 common/cmd_ide.c partition selected
2482 -46 common/cmd_ide.c Unknown partition table
2483 46 common/cmd_ide.c valid partition table found
2484 -47 common/cmd_ide.c Invalid partition type
2485 47 common/cmd_ide.c correct partition type
2486 -48 common/cmd_ide.c Error reading Image Header on boot device
2487 48 common/cmd_ide.c reading Image Header from IDE device OK
2488 -49 common/cmd_ide.c Image header has bad magic number
2489 49 common/cmd_ide.c Image header has correct magic number
2490 -50 common/cmd_ide.c Image header has bad checksum
2491 50 common/cmd_ide.c Image header has correct checksum
2492 -51 common/cmd_ide.c Error reading Image from IDE device
2493 51 common/cmd_ide.c reading Image from IDE device OK
2494 52 common/cmd_nand.c before loading a Image from a NAND device
2495 -53 common/cmd_nand.c Bad usage of "nand" command
2496 53 common/cmd_nand.c correct usage of "nand" command
2497 -54 common/cmd_nand.c No boot device
2498 54 common/cmd_nand.c boot device found
2499 -55 common/cmd_nand.c Unknown Chip ID on boot device
2500 55 common/cmd_nand.c correct chip ID found, device available
2501 -56 common/cmd_nand.c Error reading Image Header on boot device
2502 56 common/cmd_nand.c reading Image Header from NAND device OK
2503 -57 common/cmd_nand.c Image header has bad magic number
2504 57 common/cmd_nand.c Image header has correct magic number
2505 -58 common/cmd_nand.c Error reading Image from NAND device
2506 58 common/cmd_nand.c reading Image from NAND device OK
2508 -60 common/env_common.c Environment has a bad CRC, using default
2510 64 net/eth.c starting with Ethernet configuration.
2511 -64 net/eth.c no Ethernet found.
2512 65 net/eth.c Ethernet found.
2514 -80 common/cmd_net.c usage wrong
2515 80 common/cmd_net.c before calling NetLoop()
2516 -81 common/cmd_net.c some error in NetLoop() occurred
2517 81 common/cmd_net.c NetLoop() back without error
2518 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2519 82 common/cmd_net.c trying automatic boot
2520 83 common/cmd_net.c running "source" command
2521 -83 common/cmd_net.c some error in automatic boot or "source" command
2522 84 common/cmd_net.c end without errors
2527 100 common/cmd_bootm.c Kernel FIT Image has correct format
2528 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2529 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2530 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2531 102 common/cmd_bootm.c Kernel unit name specified
2532 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2533 103 common/cmd_bootm.c Found configuration node
2534 104 common/cmd_bootm.c Got kernel subimage node offset
2535 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2536 105 common/cmd_bootm.c Kernel subimage hash verification OK
2537 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2538 106 common/cmd_bootm.c Architecture check OK
2539 -106 common/cmd_bootm.c Kernel subimage has wrong type
2540 107 common/cmd_bootm.c Kernel subimage type OK
2541 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2542 108 common/cmd_bootm.c Got kernel subimage data/size
2543 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2544 -109 common/cmd_bootm.c Can't get kernel subimage type
2545 -110 common/cmd_bootm.c Can't get kernel subimage comp
2546 -111 common/cmd_bootm.c Can't get kernel subimage os
2547 -112 common/cmd_bootm.c Can't get kernel subimage load address
2548 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2550 120 common/image.c Start initial ramdisk verification
2551 -120 common/image.c Ramdisk FIT image has incorrect format
2552 121 common/image.c Ramdisk FIT image has correct format
2553 122 common/image.c No ramdisk subimage unit name, using configuration
2554 -122 common/image.c Can't get configuration for ramdisk subimage
2555 123 common/image.c Ramdisk unit name specified
2556 -124 common/image.c Can't get ramdisk subimage node offset
2557 125 common/image.c Got ramdisk subimage node offset
2558 -125 common/image.c Ramdisk subimage hash verification failed
2559 126 common/image.c Ramdisk subimage hash verification OK
2560 -126 common/image.c Ramdisk subimage for unsupported architecture
2561 127 common/image.c Architecture check OK
2562 -127 common/image.c Can't get ramdisk subimage data/size
2563 128 common/image.c Got ramdisk subimage data/size
2564 129 common/image.c Can't get ramdisk load address
2565 -129 common/image.c Got ramdisk load address
2567 -130 common/cmd_doc.c Incorrect FIT image format
2568 131 common/cmd_doc.c FIT image format OK
2570 -140 common/cmd_ide.c Incorrect FIT image format
2571 141 common/cmd_ide.c FIT image format OK
2573 -150 common/cmd_nand.c Incorrect FIT image format
2574 151 common/cmd_nand.c FIT image format OK
2576 - Standalone program support:
2577 CONFIG_STANDALONE_LOAD_ADDR
2579 This option defines a board specific value for the
2580 address where standalone program gets loaded, thus
2581 overwriting the architecture dependent default
2584 - Frame Buffer Address:
2587 Define CONFIG_FB_ADDR if you want to use specific
2588 address for frame buffer.
2589 Then system will reserve the frame buffer address to
2590 defined address instead of lcd_setmem (this function
2591 grabs the memory for frame buffer by panel's size).
2593 Please see board_init_f function.
2595 - Automatic software updates via TFTP server
2597 CONFIG_UPDATE_TFTP_CNT_MAX
2598 CONFIG_UPDATE_TFTP_MSEC_MAX
2600 These options enable and control the auto-update feature;
2601 for a more detailed description refer to doc/README.update.
2603 - MTD Support (mtdparts command, UBI support)
2606 Adds the MTD device infrastructure from the Linux kernel.
2607 Needed for mtdparts command support.
2609 CONFIG_MTD_PARTITIONS
2611 Adds the MTD partitioning infrastructure from the Linux
2612 kernel. Needed for UBI support.
2616 Enable building of SPL globally.
2619 LDSCRIPT for linking the SPL binary.
2622 Maximum binary size (text, data and rodata) of the SPL binary.
2624 CONFIG_SPL_TEXT_BASE
2625 TEXT_BASE for linking the SPL binary.
2627 CONFIG_SPL_BSS_START_ADDR
2628 Link address for the BSS within the SPL binary.
2630 CONFIG_SPL_BSS_MAX_SIZE
2631 Maximum binary size of the BSS section of the SPL binary.
2634 Adress of the start of the stack SPL will use
2636 CONFIG_SYS_SPL_MALLOC_START
2637 Starting address of the malloc pool used in SPL.
2639 CONFIG_SYS_SPL_MALLOC_SIZE
2640 The size of the malloc pool used in SPL.
2642 CONFIG_SPL_FRAMEWORK
2643 Enable the SPL framework under common/. This framework
2644 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2645 NAND loading of the Linux Kernel.
2647 CONFIG_SPL_DISPLAY_PRINT
2648 For ARM, enable an optional function to print more information
2649 about the running system.
2651 CONFIG_SPL_LIBCOMMON_SUPPORT
2652 Support for common/libcommon.o in SPL binary
2654 CONFIG_SPL_LIBDISK_SUPPORT
2655 Support for disk/libdisk.o in SPL binary
2657 CONFIG_SPL_I2C_SUPPORT
2658 Support for drivers/i2c/libi2c.o in SPL binary
2660 CONFIG_SPL_GPIO_SUPPORT
2661 Support for drivers/gpio/libgpio.o in SPL binary
2663 CONFIG_SPL_MMC_SUPPORT
2664 Support for drivers/mmc/libmmc.o in SPL binary
2666 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2667 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2668 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2669 Address, size and partition on the MMC to load U-Boot from
2670 when the MMC is being used in raw mode.
2672 CONFIG_SPL_FAT_SUPPORT
2673 Support for fs/fat/libfat.o in SPL binary
2675 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2676 Filename to read to load U-Boot when reading from FAT
2678 CONFIG_SPL_NAND_SIMPLE
2679 Support for drivers/mtd/nand/libnand.o in SPL binary
2681 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2682 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2683 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2684 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2685 CONFIG_SYS_NAND_ECCBYTES
2686 Defines the size and behavior of the NAND that SPL uses
2687 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2689 CONFIG_SYS_NAND_U_BOOT_OFFS
2690 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2693 CONFIG_SYS_NAND_U_BOOT_START
2694 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2697 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2698 Define this if you need to first read the OOB and then the
2699 data. This is used for example on davinci plattforms.
2701 CONFIG_SPL_OMAP3_ID_NAND
2702 Support for an OMAP3-specific set of functions to return the
2703 ID and MFR of the first attached NAND chip, if present.
2705 CONFIG_SPL_SERIAL_SUPPORT
2706 Support for drivers/serial/libserial.o in SPL binary
2708 CONFIG_SPL_SPI_FLASH_SUPPORT
2709 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2711 CONFIG_SPL_SPI_SUPPORT
2712 Support for drivers/spi/libspi.o in SPL binary
2714 CONFIG_SPL_RAM_DEVICE
2715 Support for running image already present in ram, in SPL binary
2717 CONFIG_SPL_LIBGENERIC_SUPPORT
2718 Support for lib/libgeneric.o in SPL binary
2723 [so far only for SMDK2400 boards]
2725 - Modem support enable:
2726 CONFIG_MODEM_SUPPORT
2728 - RTS/CTS Flow control enable:
2731 - Modem debug support:
2732 CONFIG_MODEM_SUPPORT_DEBUG
2734 Enables debugging stuff (char screen[1024], dbg())
2735 for modem support. Useful only with BDI2000.
2737 - Interrupt support (PPC):
2739 There are common interrupt_init() and timer_interrupt()
2740 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2741 for CPU specific initialization. interrupt_init_cpu()
2742 should set decrementer_count to appropriate value. If
2743 CPU resets decrementer automatically after interrupt
2744 (ppc4xx) it should set decrementer_count to zero.
2745 timer_interrupt() calls timer_interrupt_cpu() for CPU
2746 specific handling. If board has watchdog / status_led
2747 / other_activity_monitor it works automatically from
2748 general timer_interrupt().
2752 In the target system modem support is enabled when a
2753 specific key (key combination) is pressed during
2754 power-on. Otherwise U-Boot will boot normally
2755 (autoboot). The key_pressed() function is called from
2756 board_init(). Currently key_pressed() is a dummy
2757 function, returning 1 and thus enabling modem
2760 If there are no modem init strings in the
2761 environment, U-Boot proceed to autoboot; the
2762 previous output (banner, info printfs) will be
2765 See also: doc/README.Modem
2767 Board initialization settings:
2768 ------------------------------
2770 During Initialization u-boot calls a number of board specific functions
2771 to allow the preparation of board specific prerequisites, e.g. pin setup
2772 before drivers are initialized. To enable these callbacks the
2773 following configuration macros have to be defined. Currently this is
2774 architecture specific, so please check arch/your_architecture/lib/board.c
2775 typically in board_init_f() and board_init_r().
2777 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2778 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2779 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2780 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2782 Configuration Settings:
2783 -----------------------
2785 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2786 undefine this when you're short of memory.
2788 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2789 width of the commands listed in the 'help' command output.
2791 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2792 prompt for user input.
2794 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2796 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2798 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2800 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2801 the application (usually a Linux kernel) when it is
2804 - CONFIG_SYS_BAUDRATE_TABLE:
2805 List of legal baudrate settings for this board.
2807 - CONFIG_SYS_CONSOLE_INFO_QUIET
2808 Suppress display of console information at boot.
2810 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2811 If the board specific function
2812 extern int overwrite_console (void);
2813 returns 1, the stdin, stderr and stdout are switched to the
2814 serial port, else the settings in the environment are used.
2816 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2817 Enable the call to overwrite_console().
2819 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2820 Enable overwrite of previous console environment settings.
2822 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2823 Begin and End addresses of the area used by the
2826 - CONFIG_SYS_ALT_MEMTEST:
2827 Enable an alternate, more extensive memory test.
2829 - CONFIG_SYS_MEMTEST_SCRATCH:
2830 Scratch address used by the alternate memory test
2831 You only need to set this if address zero isn't writeable
2833 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2834 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2835 this specified memory area will get subtracted from the top
2836 (end) of RAM and won't get "touched" at all by U-Boot. By
2837 fixing up gd->ram_size the Linux kernel should gets passed
2838 the now "corrected" memory size and won't touch it either.
2839 This should work for arch/ppc and arch/powerpc. Only Linux
2840 board ports in arch/powerpc with bootwrapper support that
2841 recalculate the memory size from the SDRAM controller setup
2842 will have to get fixed in Linux additionally.
2844 This option can be used as a workaround for the 440EPx/GRx
2845 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2848 WARNING: Please make sure that this value is a multiple of
2849 the Linux page size (normally 4k). If this is not the case,
2850 then the end address of the Linux memory will be located at a
2851 non page size aligned address and this could cause major
2854 - CONFIG_SYS_TFTP_LOADADDR:
2855 Default load address for network file downloads
2857 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2858 Enable temporary baudrate change while serial download
2860 - CONFIG_SYS_SDRAM_BASE:
2861 Physical start address of SDRAM. _Must_ be 0 here.
2863 - CONFIG_SYS_MBIO_BASE:
2864 Physical start address of Motherboard I/O (if using a
2867 - CONFIG_SYS_FLASH_BASE:
2868 Physical start address of Flash memory.
2870 - CONFIG_SYS_MONITOR_BASE:
2871 Physical start address of boot monitor code (set by
2872 make config files to be same as the text base address
2873 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2874 CONFIG_SYS_FLASH_BASE when booting from flash.
2876 - CONFIG_SYS_MONITOR_LEN:
2877 Size of memory reserved for monitor code, used to
2878 determine _at_compile_time_ (!) if the environment is
2879 embedded within the U-Boot image, or in a separate
2882 - CONFIG_SYS_MALLOC_LEN:
2883 Size of DRAM reserved for malloc() use.
2885 - CONFIG_SYS_BOOTM_LEN:
2886 Normally compressed uImages are limited to an
2887 uncompressed size of 8 MBytes. If this is not enough,
2888 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2889 to adjust this setting to your needs.
2891 - CONFIG_SYS_BOOTMAPSZ:
2892 Maximum size of memory mapped by the startup code of
2893 the Linux kernel; all data that must be processed by
2894 the Linux kernel (bd_info, boot arguments, FDT blob if
2895 used) must be put below this limit, unless "bootm_low"
2896 enviroment variable is defined and non-zero. In such case
2897 all data for the Linux kernel must be between "bootm_low"
2898 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2899 variable "bootm_mapsize" will override the value of
2900 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2901 then the value in "bootm_size" will be used instead.
2903 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2904 Enable initrd_high functionality. If defined then the
2905 initrd_high feature is enabled and the bootm ramdisk subcommand
2908 - CONFIG_SYS_BOOT_GET_CMDLINE:
2909 Enables allocating and saving kernel cmdline in space between
2910 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2912 - CONFIG_SYS_BOOT_GET_KBD:
2913 Enables allocating and saving a kernel copy of the bd_info in
2914 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2916 - CONFIG_SYS_MAX_FLASH_BANKS:
2917 Max number of Flash memory banks
2919 - CONFIG_SYS_MAX_FLASH_SECT:
2920 Max number of sectors on a Flash chip
2922 - CONFIG_SYS_FLASH_ERASE_TOUT:
2923 Timeout for Flash erase operations (in ms)
2925 - CONFIG_SYS_FLASH_WRITE_TOUT:
2926 Timeout for Flash write operations (in ms)
2928 - CONFIG_SYS_FLASH_LOCK_TOUT
2929 Timeout for Flash set sector lock bit operation (in ms)
2931 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2932 Timeout for Flash clear lock bits operation (in ms)
2934 - CONFIG_SYS_FLASH_PROTECTION
2935 If defined, hardware flash sectors protection is used
2936 instead of U-Boot software protection.
2938 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2940 Enable TFTP transfers directly to flash memory;
2941 without this option such a download has to be
2942 performed in two steps: (1) download to RAM, and (2)
2943 copy from RAM to flash.
2945 The two-step approach is usually more reliable, since
2946 you can check if the download worked before you erase
2947 the flash, but in some situations (when system RAM is
2948 too limited to allow for a temporary copy of the
2949 downloaded image) this option may be very useful.
2951 - CONFIG_SYS_FLASH_CFI:
2952 Define if the flash driver uses extra elements in the
2953 common flash structure for storing flash geometry.
2955 - CONFIG_FLASH_CFI_DRIVER
2956 This option also enables the building of the cfi_flash driver
2957 in the drivers directory
2959 - CONFIG_FLASH_CFI_MTD
2960 This option enables the building of the cfi_mtd driver
2961 in the drivers directory. The driver exports CFI flash
2964 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2965 Use buffered writes to flash.
2967 - CONFIG_FLASH_SPANSION_S29WS_N
2968 s29ws-n MirrorBit flash has non-standard addresses for buffered
2971 - CONFIG_SYS_FLASH_QUIET_TEST
2972 If this option is defined, the common CFI flash doesn't
2973 print it's warning upon not recognized FLASH banks. This
2974 is useful, if some of the configured banks are only
2975 optionally available.
2977 - CONFIG_FLASH_SHOW_PROGRESS
2978 If defined (must be an integer), print out countdown
2979 digits and dots. Recommended value: 45 (9..1) for 80
2980 column displays, 15 (3..1) for 40 column displays.
2982 - CONFIG_SYS_RX_ETH_BUFFER:
2983 Defines the number of Ethernet receive buffers. On some
2984 Ethernet controllers it is recommended to set this value
2985 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2986 buffers can be full shortly after enabling the interface
2987 on high Ethernet traffic.
2988 Defaults to 4 if not defined.
2990 - CONFIG_ENV_MAX_ENTRIES
2992 Maximum number of entries in the hash table that is used
2993 internally to store the environment settings. The default
2994 setting is supposed to be generous and should work in most
2995 cases. This setting can be used to tune behaviour; see
2996 lib/hashtable.c for details.
2998 The following definitions that deal with the placement and management
2999 of environment data (variable area); in general, we support the
3000 following configurations:
3002 - CONFIG_BUILD_ENVCRC:
3004 Builds up envcrc with the target environment so that external utils
3005 may easily extract it and embed it in final U-Boot images.
3007 - CONFIG_ENV_IS_IN_FLASH:
3009 Define this if the environment is in flash memory.
3011 a) The environment occupies one whole flash sector, which is
3012 "embedded" in the text segment with the U-Boot code. This
3013 happens usually with "bottom boot sector" or "top boot
3014 sector" type flash chips, which have several smaller
3015 sectors at the start or the end. For instance, such a
3016 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3017 such a case you would place the environment in one of the
3018 4 kB sectors - with U-Boot code before and after it. With
3019 "top boot sector" type flash chips, you would put the
3020 environment in one of the last sectors, leaving a gap
3021 between U-Boot and the environment.
3023 - CONFIG_ENV_OFFSET:
3025 Offset of environment data (variable area) to the
3026 beginning of flash memory; for instance, with bottom boot
3027 type flash chips the second sector can be used: the offset
3028 for this sector is given here.
3030 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3034 This is just another way to specify the start address of
3035 the flash sector containing the environment (instead of
3038 - CONFIG_ENV_SECT_SIZE:
3040 Size of the sector containing the environment.
3043 b) Sometimes flash chips have few, equal sized, BIG sectors.
3044 In such a case you don't want to spend a whole sector for
3049 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3050 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3051 of this flash sector for the environment. This saves
3052 memory for the RAM copy of the environment.
3054 It may also save flash memory if you decide to use this
3055 when your environment is "embedded" within U-Boot code,
3056 since then the remainder of the flash sector could be used
3057 for U-Boot code. It should be pointed out that this is
3058 STRONGLY DISCOURAGED from a robustness point of view:
3059 updating the environment in flash makes it always
3060 necessary to erase the WHOLE sector. If something goes
3061 wrong before the contents has been restored from a copy in
3062 RAM, your target system will be dead.
3064 - CONFIG_ENV_ADDR_REDUND
3065 CONFIG_ENV_SIZE_REDUND
3067 These settings describe a second storage area used to hold
3068 a redundant copy of the environment data, so that there is
3069 a valid backup copy in case there is a power failure during
3070 a "saveenv" operation.
3072 BE CAREFUL! Any changes to the flash layout, and some changes to the
3073 source code will make it necessary to adapt <board>/u-boot.lds*
3077 - CONFIG_ENV_IS_IN_NVRAM:
3079 Define this if you have some non-volatile memory device
3080 (NVRAM, battery buffered SRAM) which you want to use for the
3086 These two #defines are used to determine the memory area you
3087 want to use for environment. It is assumed that this memory
3088 can just be read and written to, without any special
3091 BE CAREFUL! The first access to the environment happens quite early
3092 in U-Boot initalization (when we try to get the setting of for the
3093 console baudrate). You *MUST* have mapped your NVRAM area then, or
3096 Please note that even with NVRAM we still use a copy of the
3097 environment in RAM: we could work on NVRAM directly, but we want to
3098 keep settings there always unmodified except somebody uses "saveenv"
3099 to save the current settings.
3102 - CONFIG_ENV_IS_IN_EEPROM:
3104 Use this if you have an EEPROM or similar serial access
3105 device and a driver for it.
3107 - CONFIG_ENV_OFFSET:
3110 These two #defines specify the offset and size of the
3111 environment area within the total memory of your EEPROM.
3113 - CONFIG_SYS_I2C_EEPROM_ADDR:
3114 If defined, specified the chip address of the EEPROM device.
3115 The default address is zero.
3117 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3118 If defined, the number of bits used to address bytes in a
3119 single page in the EEPROM device. A 64 byte page, for example
3120 would require six bits.
3122 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3123 If defined, the number of milliseconds to delay between
3124 page writes. The default is zero milliseconds.
3126 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3127 The length in bytes of the EEPROM memory array address. Note
3128 that this is NOT the chip address length!
3130 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3131 EEPROM chips that implement "address overflow" are ones
3132 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3133 address and the extra bits end up in the "chip address" bit
3134 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3137 Note that we consider the length of the address field to
3138 still be one byte because the extra address bits are hidden
3139 in the chip address.
3141 - CONFIG_SYS_EEPROM_SIZE:
3142 The size in bytes of the EEPROM device.
3144 - CONFIG_ENV_EEPROM_IS_ON_I2C
3145 define this, if you have I2C and SPI activated, and your
3146 EEPROM, which holds the environment, is on the I2C bus.
3148 - CONFIG_I2C_ENV_EEPROM_BUS
3149 if you have an Environment on an EEPROM reached over
3150 I2C muxes, you can define here, how to reach this
3151 EEPROM. For example:
3153 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3155 EEPROM which holds the environment, is reached over
3156 a pca9547 i2c mux with address 0x70, channel 3.
3158 - CONFIG_ENV_IS_IN_DATAFLASH:
3160 Define this if you have a DataFlash memory device which you
3161 want to use for the environment.
3163 - CONFIG_ENV_OFFSET:
3167 These three #defines specify the offset and size of the
3168 environment area within the total memory of your DataFlash placed
3169 at the specified address.
3171 - CONFIG_ENV_IS_IN_REMOTE:
3173 Define this if you have a remote memory space which you
3174 want to use for the local device's environment.
3179 These two #defines specify the address and size of the
3180 environment area within the remote memory space. The
3181 local device can get the environment from remote memory
3182 space by SRIO or PCIE links.
3184 BE CAREFUL! For some special cases, the local device can not use
3185 "saveenv" command. For example, the local device will get the
3186 environment stored in a remote NOR flash by SRIO or PCIE link,
3187 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3189 - CONFIG_ENV_IS_IN_NAND:
3191 Define this if you have a NAND device which you want to use
3192 for the environment.
3194 - CONFIG_ENV_OFFSET:
3197 These two #defines specify the offset and size of the environment
3198 area within the first NAND device. CONFIG_ENV_OFFSET must be
3199 aligned to an erase block boundary.
3201 - CONFIG_ENV_OFFSET_REDUND (optional):
3203 This setting describes a second storage area of CONFIG_ENV_SIZE
3204 size used to hold a redundant copy of the environment data, so
3205 that there is a valid backup copy in case there is a power failure
3206 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3207 aligned to an erase block boundary.
3209 - CONFIG_ENV_RANGE (optional):
3211 Specifies the length of the region in which the environment
3212 can be written. This should be a multiple of the NAND device's
3213 block size. Specifying a range with more erase blocks than
3214 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3215 the range to be avoided.
3217 - CONFIG_ENV_OFFSET_OOB (optional):
3219 Enables support for dynamically retrieving the offset of the
3220 environment from block zero's out-of-band data. The
3221 "nand env.oob" command can be used to record this offset.
3222 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3223 using CONFIG_ENV_OFFSET_OOB.
3225 - CONFIG_NAND_ENV_DST
3227 Defines address in RAM to which the nand_spl code should copy the
3228 environment. If redundant environment is used, it will be copied to
3229 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3231 - CONFIG_SYS_SPI_INIT_OFFSET
3233 Defines offset to the initial SPI buffer area in DPRAM. The
3234 area is used at an early stage (ROM part) if the environment
3235 is configured to reside in the SPI EEPROM: We need a 520 byte
3236 scratch DPRAM area. It is used between the two initialization
3237 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3238 to be a good choice since it makes it far enough from the
3239 start of the data area as well as from the stack pointer.
3241 Please note that the environment is read-only until the monitor
3242 has been relocated to RAM and a RAM copy of the environment has been
3243 created; also, when using EEPROM you will have to use getenv_f()
3244 until then to read environment variables.
3246 The environment is protected by a CRC32 checksum. Before the monitor
3247 is relocated into RAM, as a result of a bad CRC you will be working
3248 with the compiled-in default environment - *silently*!!! [This is
3249 necessary, because the first environment variable we need is the
3250 "baudrate" setting for the console - if we have a bad CRC, we don't
3251 have any device yet where we could complain.]
3253 Note: once the monitor has been relocated, then it will complain if
3254 the default environment is used; a new CRC is computed as soon as you
3255 use the "saveenv" command to store a valid environment.
3257 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3258 Echo the inverted Ethernet link state to the fault LED.
3260 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3261 also needs to be defined.
3263 - CONFIG_SYS_FAULT_MII_ADDR:
3264 MII address of the PHY to check for the Ethernet link state.
3266 - CONFIG_NS16550_MIN_FUNCTIONS:
3267 Define this if you desire to only have use of the NS16550_init
3268 and NS16550_putc functions for the serial driver located at
3269 drivers/serial/ns16550.c. This option is useful for saving
3270 space for already greatly restricted images, including but not
3271 limited to NAND_SPL configurations.
3273 Low Level (hardware related) configuration options:
3274 ---------------------------------------------------
3276 - CONFIG_SYS_CACHELINE_SIZE:
3277 Cache Line Size of the CPU.
3279 - CONFIG_SYS_DEFAULT_IMMR:
3280 Default address of the IMMR after system reset.
3282 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3283 and RPXsuper) to be able to adjust the position of
3284 the IMMR register after a reset.
3286 - CONFIG_SYS_CCSRBAR_DEFAULT:
3287 Default (power-on reset) physical address of CCSR on Freescale
3290 - CONFIG_SYS_CCSRBAR:
3291 Virtual address of CCSR. On a 32-bit build, this is typically
3292 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3294 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3295 for cross-platform code that uses that macro instead.
3297 - CONFIG_SYS_CCSRBAR_PHYS:
3298 Physical address of CCSR. CCSR can be relocated to a new
3299 physical address, if desired. In this case, this macro should
3300 be set to that address. Otherwise, it should be set to the
3301 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3302 is typically relocated on 36-bit builds. It is recommended
3303 that this macro be defined via the _HIGH and _LOW macros:
3305 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3306 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3308 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3309 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3310 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3311 used in assembly code, so it must not contain typecasts or
3312 integer size suffixes (e.g. "ULL").
3314 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3315 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3316 used in assembly code, so it must not contain typecasts or
3317 integer size suffixes (e.g. "ULL").
3319 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3320 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3321 forced to a value that ensures that CCSR is not relocated.
3323 - Floppy Disk Support:
3324 CONFIG_SYS_FDC_DRIVE_NUMBER
3326 the default drive number (default value 0)
3328 CONFIG_SYS_ISA_IO_STRIDE
3330 defines the spacing between FDC chipset registers
3333 CONFIG_SYS_ISA_IO_OFFSET
3335 defines the offset of register from address. It
3336 depends on which part of the data bus is connected to
3337 the FDC chipset. (default value 0)
3339 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3340 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3343 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3344 fdc_hw_init() is called at the beginning of the FDC
3345 setup. fdc_hw_init() must be provided by the board
3346 source code. It is used to make hardware dependant
3350 Most IDE controllers were designed to be connected with PCI
3351 interface. Only few of them were designed for AHB interface.
3352 When software is doing ATA command and data transfer to
3353 IDE devices through IDE-AHB controller, some additional
3354 registers accessing to these kind of IDE-AHB controller
3357 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3358 DO NOT CHANGE unless you know exactly what you're
3359 doing! (11-4) [MPC8xx/82xx systems only]
3361 - CONFIG_SYS_INIT_RAM_ADDR:
3363 Start address of memory area that can be used for
3364 initial data and stack; please note that this must be
3365 writable memory that is working WITHOUT special
3366 initialization, i. e. you CANNOT use normal RAM which
3367 will become available only after programming the
3368 memory controller and running certain initialization
3371 U-Boot uses the following memory types:
3372 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3373 - MPC824X: data cache
3374 - PPC4xx: data cache
3376 - CONFIG_SYS_GBL_DATA_OFFSET:
3378 Offset of the initial data structure in the memory
3379 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3380 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3381 data is located at the end of the available space
3382 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3383 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3384 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3385 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3388 On the MPC824X (or other systems that use the data
3389 cache for initial memory) the address chosen for
3390 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3391 point to an otherwise UNUSED address space between
3392 the top of RAM and the start of the PCI space.
3394 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3396 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3398 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3400 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3402 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3404 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3406 - CONFIG_SYS_OR_TIMING_SDRAM:
3409 - CONFIG_SYS_MAMR_PTA:
3410 periodic timer for refresh
3412 - CONFIG_SYS_DER: Debug Event Register (37-47)
3414 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3415 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3416 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3417 CONFIG_SYS_BR1_PRELIM:
3418 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3420 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3421 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3422 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3423 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3425 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3426 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3427 Machine Mode Register and Memory Periodic Timer
3428 Prescaler definitions (SDRAM timing)
3430 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3431 enable I2C microcode relocation patch (MPC8xx);
3432 define relocation offset in DPRAM [DSP2]
3434 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3435 enable SMC microcode relocation patch (MPC8xx);
3436 define relocation offset in DPRAM [SMC1]
3438 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3439 enable SPI microcode relocation patch (MPC8xx);
3440 define relocation offset in DPRAM [SCC4]
3442 - CONFIG_SYS_USE_OSCCLK:
3443 Use OSCM clock mode on MBX8xx board. Be careful,
3444 wrong setting might damage your board. Read
3445 doc/README.MBX before setting this variable!
3447 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3448 Offset of the bootmode word in DPRAM used by post
3449 (Power On Self Tests). This definition overrides
3450 #define'd default value in commproc.h resp.
3453 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3454 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3455 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3456 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3457 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3458 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3459 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3460 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3461 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3463 - CONFIG_PCI_DISABLE_PCIE:
3464 Disable PCI-Express on systems where it is supported but not
3467 - CONFIG_PCI_ENUM_ONLY
3468 Only scan through and get the devices on the busses.
3469 Don't do any setup work, presumably because someone or
3470 something has already done it, and we don't need to do it
3471 a second time. Useful for platforms that are pre-booted
3472 by coreboot or similar.
3475 Chip has SRIO or not
3478 Board has SRIO 1 port available
3481 Board has SRIO 2 port available
3483 - CONFIG_SYS_SRIOn_MEM_VIRT:
3484 Virtual Address of SRIO port 'n' memory region
3486 - CONFIG_SYS_SRIOn_MEM_PHYS:
3487 Physical Address of SRIO port 'n' memory region
3489 - CONFIG_SYS_SRIOn_MEM_SIZE:
3490 Size of SRIO port 'n' memory region
3492 - CONFIG_SYS_NDFC_16
3493 Defined to tell the NDFC that the NAND chip is using a
3496 - CONFIG_SYS_NDFC_EBC0_CFG
3497 Sets the EBC0_CFG register for the NDFC. If not defined
3498 a default value will be used.
3501 Get DDR timing information from an I2C EEPROM. Common
3502 with pluggable memory modules such as SODIMMs
3505 I2C address of the SPD EEPROM
3507 - CONFIG_SYS_SPD_BUS_NUM
3508 If SPD EEPROM is on an I2C bus other than the first
3509 one, specify here. Note that the value must resolve
3510 to something your driver can deal with.
3512 - CONFIG_SYS_DDR_RAW_TIMING
3513 Get DDR timing information from other than SPD. Common with
3514 soldered DDR chips onboard without SPD. DDR raw timing
3515 parameters are extracted from datasheet and hard-coded into
3516 header files or board specific files.
3518 - CONFIG_FSL_DDR_INTERACTIVE
3519 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3521 - CONFIG_SYS_83XX_DDR_USES_CS0
3522 Only for 83xx systems. If specified, then DDR should
3523 be configured using CS0 and CS1 instead of CS2 and CS3.
3525 - CONFIG_ETHER_ON_FEC[12]
3526 Define to enable FEC[12] on a 8xx series processor.
3528 - CONFIG_FEC[12]_PHY
3529 Define to the hardcoded PHY address which corresponds
3530 to the given FEC; i. e.
3531 #define CONFIG_FEC1_PHY 4
3532 means that the PHY with address 4 is connected to FEC1
3534 When set to -1, means to probe for first available.
3536 - CONFIG_FEC[12]_PHY_NORXERR
3537 The PHY does not have a RXERR line (RMII only).
3538 (so program the FEC to ignore it).
3541 Enable RMII mode for all FECs.
3542 Note that this is a global option, we can't
3543 have one FEC in standard MII mode and another in RMII mode.
3545 - CONFIG_CRC32_VERIFY
3546 Add a verify option to the crc32 command.
3549 => crc32 -v <address> <count> <crc32>
3551 Where address/count indicate a memory area
3552 and crc32 is the correct crc32 which the
3556 Add the "loopw" memory command. This only takes effect if
3557 the memory commands are activated globally (CONFIG_CMD_MEM).
3560 Add the "mdc" and "mwc" memory commands. These are cyclic
3565 This command will print 4 bytes (10,11,12,13) each 500 ms.
3567 => mwc.l 100 12345678 10
3568 This command will write 12345678 to address 100 all 10 ms.
3570 This only takes effect if the memory commands are activated
3571 globally (CONFIG_CMD_MEM).
3573 - CONFIG_SKIP_LOWLEVEL_INIT
3574 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3575 low level initializations (like setting up the memory
3576 controller) are omitted and/or U-Boot does not
3577 relocate itself into RAM.
3579 Normally this variable MUST NOT be defined. The only
3580 exception is when U-Boot is loaded (to RAM) by some
3581 other boot loader or by a debugger which performs
3582 these initializations itself.
3585 Modifies the behaviour of start.S when compiling a loader
3586 that is executed before the actual U-Boot. E.g. when
3587 compiling a NAND SPL.
3589 - CONFIG_USE_ARCH_MEMCPY
3590 CONFIG_USE_ARCH_MEMSET
3591 If these options are used a optimized version of memcpy/memset will
3592 be used if available. These functions may be faster under some
3593 conditions but may increase the binary size.
3595 Freescale QE/FMAN Firmware Support:
3596 -----------------------------------
3598 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3599 loading of "firmware", which is encoded in the QE firmware binary format.
3600 This firmware often needs to be loaded during U-Boot booting, so macros
3601 are used to identify the storage device (NOR flash, SPI, etc) and the address
3604 - CONFIG_SYS_QE_FMAN_FW_ADDR
3605 The address in the storage device where the firmware is located. The
3606 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3609 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3610 The maximum possible size of the firmware. The firmware binary format
3611 has a field that specifies the actual size of the firmware, but it
3612 might not be possible to read any part of the firmware unless some
3613 local storage is allocated to hold the entire firmware first.
3615 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3616 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3617 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3618 virtual address in NOR flash.
3620 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3621 Specifies that QE/FMAN firmware is located in NAND flash.
3622 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3624 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3625 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3626 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3628 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3629 Specifies that QE/FMAN firmware is located on the primary SPI
3630 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3632 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3633 Specifies that QE/FMAN firmware is located in the remote (master)
3634 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3635 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3636 window->master inbound window->master LAW->the ucode address in
3637 master's memory space.
3639 Building the Software:
3640 ======================
3642 Building U-Boot has been tested in several native build environments
3643 and in many different cross environments. Of course we cannot support
3644 all possibly existing versions of cross development tools in all
3645 (potentially obsolete) versions. In case of tool chain problems we
3646 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3647 which is extensively used to build and test U-Boot.
3649 If you are not using a native environment, it is assumed that you
3650 have GNU cross compiling tools available in your path. In this case,
3651 you must set the environment variable CROSS_COMPILE in your shell.
3652 Note that no changes to the Makefile or any other source files are
3653 necessary. For example using the ELDK on a 4xx CPU, please enter:
3655 $ CROSS_COMPILE=ppc_4xx-
3656 $ export CROSS_COMPILE
3658 Note: If you wish to generate Windows versions of the utilities in
3659 the tools directory you can use the MinGW toolchain
3660 (http://www.mingw.org). Set your HOST tools to the MinGW
3661 toolchain and execute 'make tools'. For example:
3663 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3665 Binaries such as tools/mkimage.exe will be created which can
3666 be executed on computers running Windows.
3668 U-Boot is intended to be simple to build. After installing the
3669 sources you must configure U-Boot for one specific board type. This
3674 where "NAME_config" is the name of one of the existing configu-
3675 rations; see boards.cfg for supported names.
3677 Note: for some board special configuration names may exist; check if
3678 additional information is available from the board vendor; for
3679 instance, the TQM823L systems are available without (standard)
3680 or with LCD support. You can select such additional "features"
3681 when choosing the configuration, i. e.
3684 - will configure for a plain TQM823L, i. e. no LCD support
3686 make TQM823L_LCD_config
3687 - will configure for a TQM823L with U-Boot console on LCD
3692 Finally, type "make all", and you should get some working U-Boot
3693 images ready for download to / installation on your system:
3695 - "u-boot.bin" is a raw binary image
3696 - "u-boot" is an image in ELF binary format
3697 - "u-boot.srec" is in Motorola S-Record format
3699 By default the build is performed locally and the objects are saved
3700 in the source directory. One of the two methods can be used to change
3701 this behavior and build U-Boot to some external directory:
3703 1. Add O= to the make command line invocations:
3705 make O=/tmp/build distclean
3706 make O=/tmp/build NAME_config
3707 make O=/tmp/build all
3709 2. Set environment variable BUILD_DIR to point to the desired location:
3711 export BUILD_DIR=/tmp/build
3716 Note that the command line "O=" setting overrides the BUILD_DIR environment
3720 Please be aware that the Makefiles assume you are using GNU make, so
3721 for instance on NetBSD you might need to use "gmake" instead of
3725 If the system board that you have is not listed, then you will need
3726 to port U-Boot to your hardware platform. To do this, follow these
3729 1. Add a new configuration option for your board to the toplevel
3730 "boards.cfg" file, using the existing entries as examples.
3731 Follow the instructions there to keep the boards in order.
3732 2. Create a new directory to hold your board specific code. Add any
3733 files you need. In your board directory, you will need at least
3734 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3735 3. Create a new configuration file "include/configs/<board>.h" for
3737 3. If you're porting U-Boot to a new CPU, then also create a new
3738 directory to hold your CPU specific code. Add any files you need.
3739 4. Run "make <board>_config" with your new name.
3740 5. Type "make", and you should get a working "u-boot.srec" file
3741 to be installed on your target system.
3742 6. Debug and solve any problems that might arise.
3743 [Of course, this last step is much harder than it sounds.]
3746 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3747 ==============================================================
3749 If you have modified U-Boot sources (for instance added a new board
3750 or support for new devices, a new CPU, etc.) you are expected to
3751 provide feedback to the other developers. The feedback normally takes
3752 the form of a "patch", i. e. a context diff against a certain (latest
3753 official or latest in the git repository) version of U-Boot sources.
3755 But before you submit such a patch, please verify that your modifi-
3756 cation did not break existing code. At least make sure that *ALL* of
3757 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3758 just run the "MAKEALL" script, which will configure and build U-Boot
3759 for ALL supported system. Be warned, this will take a while. You can
3760 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3761 environment variable to the script, i. e. to use the ELDK cross tools
3764 CROSS_COMPILE=ppc_8xx- MAKEALL
3766 or to build on a native PowerPC system you can type
3768 CROSS_COMPILE=' ' MAKEALL
3770 When using the MAKEALL script, the default behaviour is to build
3771 U-Boot in the source directory. This location can be changed by
3772 setting the BUILD_DIR environment variable. Also, for each target
3773 built, the MAKEALL script saves two log files (<target>.ERR and
3774 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3775 location can be changed by setting the MAKEALL_LOGDIR environment
3776 variable. For example:
3778 export BUILD_DIR=/tmp/build
3779 export MAKEALL_LOGDIR=/tmp/log
3780 CROSS_COMPILE=ppc_8xx- MAKEALL
3782 With the above settings build objects are saved in the /tmp/build,
3783 log files are saved in the /tmp/log and the source tree remains clean
3784 during the whole build process.
3787 See also "U-Boot Porting Guide" below.
3790 Monitor Commands - Overview:
3791 ============================
3793 go - start application at address 'addr'
3794 run - run commands in an environment variable
3795 bootm - boot application image from memory
3796 bootp - boot image via network using BootP/TFTP protocol
3797 bootz - boot zImage from memory
3798 tftpboot- boot image via network using TFTP protocol
3799 and env variables "ipaddr" and "serverip"
3800 (and eventually "gatewayip")
3801 tftpput - upload a file via network using TFTP protocol
3802 rarpboot- boot image via network using RARP/TFTP protocol
3803 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3804 loads - load S-Record file over serial line
3805 loadb - load binary file over serial line (kermit mode)
3807 mm - memory modify (auto-incrementing)
3808 nm - memory modify (constant address)
3809 mw - memory write (fill)
3811 cmp - memory compare
3812 crc32 - checksum calculation
3813 i2c - I2C sub-system
3814 sspi - SPI utility commands
3815 base - print or set address offset
3816 printenv- print environment variables
3817 setenv - set environment variables
3818 saveenv - save environment variables to persistent storage
3819 protect - enable or disable FLASH write protection
3820 erase - erase FLASH memory
3821 flinfo - print FLASH memory information
3822 bdinfo - print Board Info structure
3823 iminfo - print header information for application image
3824 coninfo - print console devices and informations
3825 ide - IDE sub-system
3826 loop - infinite loop on address range
3827 loopw - infinite write loop on address range
3828 mtest - simple RAM test
3829 icache - enable or disable instruction cache
3830 dcache - enable or disable data cache
3831 reset - Perform RESET of the CPU
3832 echo - echo args to console
3833 version - print monitor version
3834 help - print online help
3835 ? - alias for 'help'
3838 Monitor Commands - Detailed Description:
3839 ========================================
3843 For now: just type "help <command>".
3846 Environment Variables:
3847 ======================
3849 U-Boot supports user configuration using Environment Variables which
3850 can be made persistent by saving to Flash memory.
3852 Environment Variables are set using "setenv", printed using
3853 "printenv", and saved to Flash using "saveenv". Using "setenv"
3854 without a value can be used to delete a variable from the
3855 environment. As long as you don't save the environment you are
3856 working with an in-memory copy. In case the Flash area containing the
3857 environment is erased by accident, a default environment is provided.
3859 Some configuration options can be set using Environment Variables.
3861 List of environment variables (most likely not complete):
3863 baudrate - see CONFIG_BAUDRATE
3865 bootdelay - see CONFIG_BOOTDELAY
3867 bootcmd - see CONFIG_BOOTCOMMAND
3869 bootargs - Boot arguments when booting an RTOS image
3871 bootfile - Name of the image to load with TFTP
3873 bootm_low - Memory range available for image processing in the bootm
3874 command can be restricted. This variable is given as
3875 a hexadecimal number and defines lowest address allowed
3876 for use by the bootm command. See also "bootm_size"
3877 environment variable. Address defined by "bootm_low" is
3878 also the base of the initial memory mapping for the Linux
3879 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3882 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3883 This variable is given as a hexadecimal number and it
3884 defines the size of the memory region starting at base
3885 address bootm_low that is accessible by the Linux kernel
3886 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3887 as the default value if it is defined, and bootm_size is
3890 bootm_size - Memory range available for image processing in the bootm
3891 command can be restricted. This variable is given as
3892 a hexadecimal number and defines the size of the region
3893 allowed for use by the bootm command. See also "bootm_low"
3894 environment variable.
3896 updatefile - Location of the software update file on a TFTP server, used
3897 by the automatic software update feature. Please refer to
3898 documentation in doc/README.update for more details.
3900 autoload - if set to "no" (any string beginning with 'n'),
3901 "bootp" will just load perform a lookup of the
3902 configuration from the BOOTP server, but not try to
3903 load any image using TFTP
3905 autostart - if set to "yes", an image loaded using the "bootp",
3906 "rarpboot", "tftpboot" or "diskboot" commands will
3907 be automatically started (by internally calling
3910 If set to "no", a standalone image passed to the
3911 "bootm" command will be copied to the load address
3912 (and eventually uncompressed), but NOT be started.
3913 This can be used to load and uncompress arbitrary
3916 fdt_high - if set this restricts the maximum address that the
3917 flattened device tree will be copied into upon boot.
3918 For example, if you have a system with 1 GB memory
3919 at physical address 0x10000000, while Linux kernel
3920 only recognizes the first 704 MB as low memory, you
3921 may need to set fdt_high as 0x3C000000 to have the
3922 device tree blob be copied to the maximum address
3923 of the 704 MB low memory, so that Linux kernel can
3924 access it during the boot procedure.
3926 If this is set to the special value 0xFFFFFFFF then
3927 the fdt will not be copied at all on boot. For this
3928 to work it must reside in writable memory, have
3929 sufficient padding on the end of it for u-boot to
3930 add the information it needs into it, and the memory
3931 must be accessible by the kernel.
3933 fdtcontroladdr- if set this is the address of the control flattened
3934 device tree used by U-Boot when CONFIG_OF_CONTROL is
3937 i2cfast - (PPC405GP|PPC405EP only)
3938 if set to 'y' configures Linux I2C driver for fast
3939 mode (400kHZ). This environment variable is used in
3940 initialization code. So, for changes to be effective
3941 it must be saved and board must be reset.
3943 initrd_high - restrict positioning of initrd images:
3944 If this variable is not set, initrd images will be
3945 copied to the highest possible address in RAM; this
3946 is usually what you want since it allows for
3947 maximum initrd size. If for some reason you want to
3948 make sure that the initrd image is loaded below the
3949 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3950 variable to a value of "no" or "off" or "0".
3951 Alternatively, you can set it to a maximum upper
3952 address to use (U-Boot will still check that it
3953 does not overwrite the U-Boot stack and data).
3955 For instance, when you have a system with 16 MB
3956 RAM, and want to reserve 4 MB from use by Linux,
3957 you can do this by adding "mem=12M" to the value of
3958 the "bootargs" variable. However, now you must make
3959 sure that the initrd image is placed in the first
3960 12 MB as well - this can be done with
3962 setenv initrd_high 00c00000
3964 If you set initrd_high to 0xFFFFFFFF, this is an
3965 indication to U-Boot that all addresses are legal
3966 for the Linux kernel, including addresses in flash
3967 memory. In this case U-Boot will NOT COPY the
3968 ramdisk at all. This may be useful to reduce the
3969 boot time on your system, but requires that this
3970 feature is supported by your Linux kernel.
3972 ipaddr - IP address; needed for tftpboot command
3974 loadaddr - Default load address for commands like "bootp",
3975 "rarpboot", "tftpboot", "loadb" or "diskboot"
3977 loads_echo - see CONFIG_LOADS_ECHO
3979 serverip - TFTP server IP address; needed for tftpboot command
3981 bootretry - see CONFIG_BOOT_RETRY_TIME
3983 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3985 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3987 ethprime - controls which interface is used first.
3989 ethact - controls which interface is currently active.
3990 For example you can do the following
3992 => setenv ethact FEC
3993 => ping 192.168.0.1 # traffic sent on FEC
3994 => setenv ethact SCC
3995 => ping 10.0.0.1 # traffic sent on SCC
3997 ethrotate - When set to "no" U-Boot does not go through all
3998 available network interfaces.
3999 It just stays at the currently selected interface.
4001 netretry - When set to "no" each network operation will
4002 either succeed or fail without retrying.
4003 When set to "once" the network operation will
4004 fail when all the available network interfaces
4005 are tried once without success.
4006 Useful on scripts which control the retry operation
4009 npe_ucode - set load address for the NPE microcode
4011 tftpsrcport - If this is set, the value is used for TFTP's
4014 tftpdstport - If this is set, the value is used for TFTP's UDP
4015 destination port instead of the Well Know Port 69.
4017 tftpblocksize - Block size to use for TFTP transfers; if not set,
4018 we use the TFTP server's default block size
4020 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4021 seconds, minimum value is 1000 = 1 second). Defines
4022 when a packet is considered to be lost so it has to
4023 be retransmitted. The default is 5000 = 5 seconds.
4024 Lowering this value may make downloads succeed
4025 faster in networks with high packet loss rates or
4026 with unreliable TFTP servers.
4028 vlan - When set to a value < 4095 the traffic over
4029 Ethernet is encapsulated/received over 802.1q
4032 The following image location variables contain the location of images
4033 used in booting. The "Image" column gives the role of the image and is
4034 not an environment variable name. The other columns are environment
4035 variable names. "File Name" gives the name of the file on a TFTP
4036 server, "RAM Address" gives the location in RAM the image will be
4037 loaded to, and "Flash Location" gives the image's address in NOR
4038 flash or offset in NAND flash.
4040 *Note* - these variables don't have to be defined for all boards, some
4041 boards currenlty use other variables for these purposes, and some
4042 boards use these variables for other purposes.
4044 Image File Name RAM Address Flash Location
4045 ----- --------- ----------- --------------
4046 u-boot u-boot u-boot_addr_r u-boot_addr
4047 Linux kernel bootfile kernel_addr_r kernel_addr
4048 device tree blob fdtfile fdt_addr_r fdt_addr
4049 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4051 The following environment variables may be used and automatically
4052 updated by the network boot commands ("bootp" and "rarpboot"),
4053 depending the information provided by your boot server:
4055 bootfile - see above
4056 dnsip - IP address of your Domain Name Server
4057 dnsip2 - IP address of your secondary Domain Name Server
4058 gatewayip - IP address of the Gateway (Router) to use
4059 hostname - Target hostname
4061 netmask - Subnet Mask
4062 rootpath - Pathname of the root filesystem on the NFS server
4063 serverip - see above
4066 There are two special Environment Variables:
4068 serial# - contains hardware identification information such
4069 as type string and/or serial number
4070 ethaddr - Ethernet address
4072 These variables can be set only once (usually during manufacturing of
4073 the board). U-Boot refuses to delete or overwrite these variables
4074 once they have been set once.
4077 Further special Environment Variables:
4079 ver - Contains the U-Boot version string as printed
4080 with the "version" command. This variable is
4081 readonly (see CONFIG_VERSION_VARIABLE).
4084 Please note that changes to some configuration parameters may take
4085 only effect after the next boot (yes, that's just like Windoze :-).
4088 Command Line Parsing:
4089 =====================
4091 There are two different command line parsers available with U-Boot:
4092 the old "simple" one, and the much more powerful "hush" shell:
4094 Old, simple command line parser:
4095 --------------------------------
4097 - supports environment variables (through setenv / saveenv commands)
4098 - several commands on one line, separated by ';'
4099 - variable substitution using "... ${name} ..." syntax
4100 - special characters ('$', ';') can be escaped by prefixing with '\',
4102 setenv bootcmd bootm \${address}
4103 - You can also escape text by enclosing in single apostrophes, for example:
4104 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4109 - similar to Bourne shell, with control structures like
4110 if...then...else...fi, for...do...done; while...do...done,
4111 until...do...done, ...
4112 - supports environment ("global") variables (through setenv / saveenv
4113 commands) and local shell variables (through standard shell syntax
4114 "name=value"); only environment variables can be used with "run"
4120 (1) If a command line (or an environment variable executed by a "run"
4121 command) contains several commands separated by semicolon, and
4122 one of these commands fails, then the remaining commands will be
4125 (2) If you execute several variables with one call to run (i. e.
4126 calling run with a list of variables as arguments), any failing
4127 command will cause "run" to terminate, i. e. the remaining
4128 variables are not executed.
4130 Note for Redundant Ethernet Interfaces:
4131 =======================================
4133 Some boards come with redundant Ethernet interfaces; U-Boot supports
4134 such configurations and is capable of automatic selection of a
4135 "working" interface when needed. MAC assignment works as follows:
4137 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4138 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4139 "eth1addr" (=>eth1), "eth2addr", ...
4141 If the network interface stores some valid MAC address (for instance
4142 in SROM), this is used as default address if there is NO correspon-
4143 ding setting in the environment; if the corresponding environment
4144 variable is set, this overrides the settings in the card; that means:
4146 o If the SROM has a valid MAC address, and there is no address in the
4147 environment, the SROM's address is used.
4149 o If there is no valid address in the SROM, and a definition in the
4150 environment exists, then the value from the environment variable is
4153 o If both the SROM and the environment contain a MAC address, and
4154 both addresses are the same, this MAC address is used.
4156 o If both the SROM and the environment contain a MAC address, and the
4157 addresses differ, the value from the environment is used and a
4160 o If neither SROM nor the environment contain a MAC address, an error
4163 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4164 will be programmed into hardware as part of the initialization process. This
4165 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4166 The naming convention is as follows:
4167 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4172 U-Boot is capable of booting (and performing other auxiliary operations on)
4173 images in two formats:
4175 New uImage format (FIT)
4176 -----------------------
4178 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4179 to Flattened Device Tree). It allows the use of images with multiple
4180 components (several kernels, ramdisks, etc.), with contents protected by
4181 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4187 Old image format is based on binary files which can be basically anything,
4188 preceded by a special header; see the definitions in include/image.h for
4189 details; basically, the header defines the following image properties:
4191 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4192 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4193 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4194 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4196 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4197 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4198 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4199 * Compression Type (uncompressed, gzip, bzip2)
4205 The header is marked by a special Magic Number, and both the header
4206 and the data portions of the image are secured against corruption by
4213 Although U-Boot should support any OS or standalone application
4214 easily, the main focus has always been on Linux during the design of
4217 U-Boot includes many features that so far have been part of some
4218 special "boot loader" code within the Linux kernel. Also, any
4219 "initrd" images to be used are no longer part of one big Linux image;
4220 instead, kernel and "initrd" are separate images. This implementation
4221 serves several purposes:
4223 - the same features can be used for other OS or standalone
4224 applications (for instance: using compressed images to reduce the
4225 Flash memory footprint)
4227 - it becomes much easier to port new Linux kernel versions because
4228 lots of low-level, hardware dependent stuff are done by U-Boot
4230 - the same Linux kernel image can now be used with different "initrd"
4231 images; of course this also means that different kernel images can
4232 be run with the same "initrd". This makes testing easier (you don't
4233 have to build a new "zImage.initrd" Linux image when you just
4234 change a file in your "initrd"). Also, a field-upgrade of the
4235 software is easier now.
4241 Porting Linux to U-Boot based systems:
4242 ---------------------------------------
4244 U-Boot cannot save you from doing all the necessary modifications to
4245 configure the Linux device drivers for use with your target hardware
4246 (no, we don't intend to provide a full virtual machine interface to
4249 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4251 Just make sure your machine specific header file (for instance
4252 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4253 Information structure as we define in include/asm-<arch>/u-boot.h,
4254 and make sure that your definition of IMAP_ADDR uses the same value
4255 as your U-Boot configuration in CONFIG_SYS_IMMR.
4258 Configuring the Linux kernel:
4259 -----------------------------
4261 No specific requirements for U-Boot. Make sure you have some root
4262 device (initial ramdisk, NFS) for your target system.
4265 Building a Linux Image:
4266 -----------------------
4268 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4269 not used. If you use recent kernel source, a new build target
4270 "uImage" will exist which automatically builds an image usable by
4271 U-Boot. Most older kernels also have support for a "pImage" target,
4272 which was introduced for our predecessor project PPCBoot and uses a
4273 100% compatible format.
4282 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4283 encapsulate a compressed Linux kernel image with header information,
4284 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4286 * build a standard "vmlinux" kernel image (in ELF binary format):
4288 * convert the kernel into a raw binary image:
4290 ${CROSS_COMPILE}-objcopy -O binary \
4291 -R .note -R .comment \
4292 -S vmlinux linux.bin
4294 * compress the binary image:
4298 * package compressed binary image for U-Boot:
4300 mkimage -A ppc -O linux -T kernel -C gzip \
4301 -a 0 -e 0 -n "Linux Kernel Image" \
4302 -d linux.bin.gz uImage
4305 The "mkimage" tool can also be used to create ramdisk images for use
4306 with U-Boot, either separated from the Linux kernel image, or
4307 combined into one file. "mkimage" encapsulates the images with a 64
4308 byte header containing information about target architecture,
4309 operating system, image type, compression method, entry points, time
4310 stamp, CRC32 checksums, etc.
4312 "mkimage" can be called in two ways: to verify existing images and
4313 print the header information, or to build new images.
4315 In the first form (with "-l" option) mkimage lists the information
4316 contained in the header of an existing U-Boot image; this includes
4317 checksum verification:
4319 tools/mkimage -l image
4320 -l ==> list image header information
4322 The second form (with "-d" option) is used to build a U-Boot image
4323 from a "data file" which is used as image payload:
4325 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4326 -n name -d data_file image
4327 -A ==> set architecture to 'arch'
4328 -O ==> set operating system to 'os'
4329 -T ==> set image type to 'type'
4330 -C ==> set compression type 'comp'
4331 -a ==> set load address to 'addr' (hex)
4332 -e ==> set entry point to 'ep' (hex)
4333 -n ==> set image name to 'name'
4334 -d ==> use image data from 'datafile'
4336 Right now, all Linux kernels for PowerPC systems use the same load
4337 address (0x00000000), but the entry point address depends on the
4340 - 2.2.x kernels have the entry point at 0x0000000C,
4341 - 2.3.x and later kernels have the entry point at 0x00000000.
4343 So a typical call to build a U-Boot image would read:
4345 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4346 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4347 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4348 > examples/uImage.TQM850L
4349 Image Name: 2.4.4 kernel for TQM850L
4350 Created: Wed Jul 19 02:34:59 2000
4351 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4352 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4353 Load Address: 0x00000000
4354 Entry Point: 0x00000000
4356 To verify the contents of the image (or check for corruption):
4358 -> tools/mkimage -l examples/uImage.TQM850L
4359 Image Name: 2.4.4 kernel for TQM850L
4360 Created: Wed Jul 19 02:34:59 2000
4361 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4362 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4363 Load Address: 0x00000000
4364 Entry Point: 0x00000000
4366 NOTE: for embedded systems where boot time is critical you can trade
4367 speed for memory and install an UNCOMPRESSED image instead: this
4368 needs more space in Flash, but boots much faster since it does not
4369 need to be uncompressed:
4371 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4372 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4373 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4374 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4375 > examples/uImage.TQM850L-uncompressed
4376 Image Name: 2.4.4 kernel for TQM850L
4377 Created: Wed Jul 19 02:34:59 2000
4378 Image Type: PowerPC Linux Kernel Image (uncompressed)
4379 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4380 Load Address: 0x00000000
4381 Entry Point: 0x00000000
4384 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4385 when your kernel is intended to use an initial ramdisk:
4387 -> tools/mkimage -n 'Simple Ramdisk Image' \
4388 > -A ppc -O linux -T ramdisk -C gzip \
4389 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4390 Image Name: Simple Ramdisk Image
4391 Created: Wed Jan 12 14:01:50 2000
4392 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4393 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4394 Load Address: 0x00000000
4395 Entry Point: 0x00000000
4398 Installing a Linux Image:
4399 -------------------------
4401 To downloading a U-Boot image over the serial (console) interface,
4402 you must convert the image to S-Record format:
4404 objcopy -I binary -O srec examples/image examples/image.srec
4406 The 'objcopy' does not understand the information in the U-Boot
4407 image header, so the resulting S-Record file will be relative to
4408 address 0x00000000. To load it to a given address, you need to
4409 specify the target address as 'offset' parameter with the 'loads'
4412 Example: install the image to address 0x40100000 (which on the
4413 TQM8xxL is in the first Flash bank):
4415 => erase 40100000 401FFFFF
4421 ## Ready for S-Record download ...
4422 ~>examples/image.srec
4423 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4425 15989 15990 15991 15992
4426 [file transfer complete]
4428 ## Start Addr = 0x00000000
4431 You can check the success of the download using the 'iminfo' command;
4432 this includes a checksum verification so you can be sure no data
4433 corruption happened:
4437 ## Checking Image at 40100000 ...
4438 Image Name: 2.2.13 for initrd on TQM850L
4439 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4440 Data Size: 335725 Bytes = 327 kB = 0 MB
4441 Load Address: 00000000
4442 Entry Point: 0000000c
4443 Verifying Checksum ... OK
4449 The "bootm" command is used to boot an application that is stored in
4450 memory (RAM or Flash). In case of a Linux kernel image, the contents
4451 of the "bootargs" environment variable is passed to the kernel as
4452 parameters. You can check and modify this variable using the
4453 "printenv" and "setenv" commands:
4456 => printenv bootargs
4457 bootargs=root=/dev/ram
4459 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4461 => printenv bootargs
4462 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4465 ## Booting Linux kernel at 40020000 ...
4466 Image Name: 2.2.13 for NFS on TQM850L
4467 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4468 Data Size: 381681 Bytes = 372 kB = 0 MB
4469 Load Address: 00000000
4470 Entry Point: 0000000c
4471 Verifying Checksum ... OK
4472 Uncompressing Kernel Image ... OK
4473 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4474 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4475 time_init: decrementer frequency = 187500000/60
4476 Calibrating delay loop... 49.77 BogoMIPS
4477 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4480 If you want to boot a Linux kernel with initial RAM disk, you pass
4481 the memory addresses of both the kernel and the initrd image (PPBCOOT
4482 format!) to the "bootm" command:
4484 => imi 40100000 40200000
4486 ## Checking Image at 40100000 ...
4487 Image Name: 2.2.13 for initrd on TQM850L
4488 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4489 Data Size: 335725 Bytes = 327 kB = 0 MB
4490 Load Address: 00000000
4491 Entry Point: 0000000c
4492 Verifying Checksum ... OK
4494 ## Checking Image at 40200000 ...
4495 Image Name: Simple Ramdisk Image
4496 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4497 Data Size: 566530 Bytes = 553 kB = 0 MB
4498 Load Address: 00000000
4499 Entry Point: 00000000
4500 Verifying Checksum ... OK
4502 => bootm 40100000 40200000
4503 ## Booting Linux kernel at 40100000 ...
4504 Image Name: 2.2.13 for initrd on TQM850L
4505 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4506 Data Size: 335725 Bytes = 327 kB = 0 MB
4507 Load Address: 00000000
4508 Entry Point: 0000000c
4509 Verifying Checksum ... OK
4510 Uncompressing Kernel Image ... OK
4511 ## Loading RAMDisk Image at 40200000 ...
4512 Image Name: Simple Ramdisk Image
4513 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4514 Data Size: 566530 Bytes = 553 kB = 0 MB
4515 Load Address: 00000000
4516 Entry Point: 00000000
4517 Verifying Checksum ... OK
4518 Loading Ramdisk ... OK
4519 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4520 Boot arguments: root=/dev/ram
4521 time_init: decrementer frequency = 187500000/60
4522 Calibrating delay loop... 49.77 BogoMIPS
4524 RAMDISK: Compressed image found at block 0
4525 VFS: Mounted root (ext2 filesystem).
4529 Boot Linux and pass a flat device tree:
4532 First, U-Boot must be compiled with the appropriate defines. See the section
4533 titled "Linux Kernel Interface" above for a more in depth explanation. The
4534 following is an example of how to start a kernel and pass an updated
4540 oft=oftrees/mpc8540ads.dtb
4541 => tftp $oftaddr $oft
4542 Speed: 1000, full duplex
4544 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4545 Filename 'oftrees/mpc8540ads.dtb'.
4546 Load address: 0x300000
4549 Bytes transferred = 4106 (100a hex)
4550 => tftp $loadaddr $bootfile
4551 Speed: 1000, full duplex
4553 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4555 Load address: 0x200000
4556 Loading:############
4558 Bytes transferred = 1029407 (fb51f hex)
4563 => bootm $loadaddr - $oftaddr
4564 ## Booting image at 00200000 ...
4565 Image Name: Linux-2.6.17-dirty
4566 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4567 Data Size: 1029343 Bytes = 1005.2 kB
4568 Load Address: 00000000
4569 Entry Point: 00000000
4570 Verifying Checksum ... OK
4571 Uncompressing Kernel Image ... OK
4572 Booting using flat device tree at 0x300000
4573 Using MPC85xx ADS machine description
4574 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4578 More About U-Boot Image Types:
4579 ------------------------------
4581 U-Boot supports the following image types:
4583 "Standalone Programs" are directly runnable in the environment
4584 provided by U-Boot; it is expected that (if they behave
4585 well) you can continue to work in U-Boot after return from
4586 the Standalone Program.
4587 "OS Kernel Images" are usually images of some Embedded OS which
4588 will take over control completely. Usually these programs
4589 will install their own set of exception handlers, device
4590 drivers, set up the MMU, etc. - this means, that you cannot
4591 expect to re-enter U-Boot except by resetting the CPU.
4592 "RAMDisk Images" are more or less just data blocks, and their
4593 parameters (address, size) are passed to an OS kernel that is
4595 "Multi-File Images" contain several images, typically an OS
4596 (Linux) kernel image and one or more data images like
4597 RAMDisks. This construct is useful for instance when you want
4598 to boot over the network using BOOTP etc., where the boot
4599 server provides just a single image file, but you want to get
4600 for instance an OS kernel and a RAMDisk image.
4602 "Multi-File Images" start with a list of image sizes, each
4603 image size (in bytes) specified by an "uint32_t" in network
4604 byte order. This list is terminated by an "(uint32_t)0".
4605 Immediately after the terminating 0 follow the images, one by
4606 one, all aligned on "uint32_t" boundaries (size rounded up to
4607 a multiple of 4 bytes).
4609 "Firmware Images" are binary images containing firmware (like
4610 U-Boot or FPGA images) which usually will be programmed to
4613 "Script files" are command sequences that will be executed by
4614 U-Boot's command interpreter; this feature is especially
4615 useful when you configure U-Boot to use a real shell (hush)
4616 as command interpreter.
4618 Booting the Linux zImage:
4619 -------------------------
4621 On some platforms, it's possible to boot Linux zImage. This is done
4622 using the "bootz" command. The syntax of "bootz" command is the same
4623 as the syntax of "bootm" command.
4625 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4626 kernel with raw initrd images. The syntax is slightly different, the
4627 address of the initrd must be augmented by it's size, in the following
4628 format: "<initrd addres>:<initrd size>".
4634 One of the features of U-Boot is that you can dynamically load and
4635 run "standalone" applications, which can use some resources of
4636 U-Boot like console I/O functions or interrupt services.
4638 Two simple examples are included with the sources:
4643 'examples/hello_world.c' contains a small "Hello World" Demo
4644 application; it is automatically compiled when you build U-Boot.
4645 It's configured to run at address 0x00040004, so you can play with it
4649 ## Ready for S-Record download ...
4650 ~>examples/hello_world.srec
4651 1 2 3 4 5 6 7 8 9 10 11 ...
4652 [file transfer complete]
4654 ## Start Addr = 0x00040004
4656 => go 40004 Hello World! This is a test.
4657 ## Starting application at 0x00040004 ...
4668 Hit any key to exit ...
4670 ## Application terminated, rc = 0x0
4672 Another example, which demonstrates how to register a CPM interrupt
4673 handler with the U-Boot code, can be found in 'examples/timer.c'.
4674 Here, a CPM timer is set up to generate an interrupt every second.
4675 The interrupt service routine is trivial, just printing a '.'
4676 character, but this is just a demo program. The application can be
4677 controlled by the following keys:
4679 ? - print current values og the CPM Timer registers
4680 b - enable interrupts and start timer
4681 e - stop timer and disable interrupts
4682 q - quit application
4685 ## Ready for S-Record download ...
4686 ~>examples/timer.srec
4687 1 2 3 4 5 6 7 8 9 10 11 ...
4688 [file transfer complete]
4690 ## Start Addr = 0x00040004
4693 ## Starting application at 0x00040004 ...
4696 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4699 [q, b, e, ?] Set interval 1000000 us
4702 [q, b, e, ?] ........
4703 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4706 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4709 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4712 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4714 [q, b, e, ?] ...Stopping timer
4716 [q, b, e, ?] ## Application terminated, rc = 0x0
4722 Over time, many people have reported problems when trying to use the
4723 "minicom" terminal emulation program for serial download. I (wd)
4724 consider minicom to be broken, and recommend not to use it. Under
4725 Unix, I recommend to use C-Kermit for general purpose use (and
4726 especially for kermit binary protocol download ("loadb" command), and
4727 use "cu" for S-Record download ("loads" command). See
4728 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4729 for help with kermit.
4732 Nevertheless, if you absolutely want to use it try adding this
4733 configuration to your "File transfer protocols" section:
4735 Name Program Name U/D FullScr IO-Red. Multi
4736 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4737 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4743 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4744 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4746 Building requires a cross environment; it is known to work on
4747 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4748 need gmake since the Makefiles are not compatible with BSD make).
4749 Note that the cross-powerpc package does not install include files;
4750 attempting to build U-Boot will fail because <machine/ansi.h> is
4751 missing. This file has to be installed and patched manually:
4753 # cd /usr/pkg/cross/powerpc-netbsd/include
4755 # ln -s powerpc machine
4756 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4757 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4759 Native builds *don't* work due to incompatibilities between native
4760 and U-Boot include files.
4762 Booting assumes that (the first part of) the image booted is a
4763 stage-2 loader which in turn loads and then invokes the kernel
4764 proper. Loader sources will eventually appear in the NetBSD source
4765 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4766 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4769 Implementation Internals:
4770 =========================
4772 The following is not intended to be a complete description of every
4773 implementation detail. However, it should help to understand the
4774 inner workings of U-Boot and make it easier to port it to custom
4778 Initial Stack, Global Data:
4779 ---------------------------
4781 The implementation of U-Boot is complicated by the fact that U-Boot
4782 starts running out of ROM (flash memory), usually without access to
4783 system RAM (because the memory controller is not initialized yet).
4784 This means that we don't have writable Data or BSS segments, and BSS
4785 is not initialized as zero. To be able to get a C environment working
4786 at all, we have to allocate at least a minimal stack. Implementation
4787 options for this are defined and restricted by the CPU used: Some CPU
4788 models provide on-chip memory (like the IMMR area on MPC8xx and
4789 MPC826x processors), on others (parts of) the data cache can be
4790 locked as (mis-) used as memory, etc.
4792 Chris Hallinan posted a good summary of these issues to the
4793 U-Boot mailing list:
4795 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4796 From: "Chris Hallinan" <clh@net1plus.com>
4797 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4800 Correct me if I'm wrong, folks, but the way I understand it
4801 is this: Using DCACHE as initial RAM for Stack, etc, does not
4802 require any physical RAM backing up the cache. The cleverness
4803 is that the cache is being used as a temporary supply of
4804 necessary storage before the SDRAM controller is setup. It's
4805 beyond the scope of this list to explain the details, but you
4806 can see how this works by studying the cache architecture and
4807 operation in the architecture and processor-specific manuals.
4809 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4810 is another option for the system designer to use as an
4811 initial stack/RAM area prior to SDRAM being available. Either
4812 option should work for you. Using CS 4 should be fine if your
4813 board designers haven't used it for something that would
4814 cause you grief during the initial boot! It is frequently not
4817 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4818 with your processor/board/system design. The default value
4819 you will find in any recent u-boot distribution in
4820 walnut.h should work for you. I'd set it to a value larger
4821 than your SDRAM module. If you have a 64MB SDRAM module, set
4822 it above 400_0000. Just make sure your board has no resources
4823 that are supposed to respond to that address! That code in
4824 start.S has been around a while and should work as is when
4825 you get the config right.
4830 It is essential to remember this, since it has some impact on the C
4831 code for the initialization procedures:
4833 * Initialized global data (data segment) is read-only. Do not attempt
4836 * Do not use any uninitialized global data (or implicitely initialized
4837 as zero data - BSS segment) at all - this is undefined, initiali-
4838 zation is performed later (when relocating to RAM).
4840 * Stack space is very limited. Avoid big data buffers or things like
4843 Having only the stack as writable memory limits means we cannot use
4844 normal global data to share information beween the code. But it
4845 turned out that the implementation of U-Boot can be greatly
4846 simplified by making a global data structure (gd_t) available to all
4847 functions. We could pass a pointer to this data as argument to _all_
4848 functions, but this would bloat the code. Instead we use a feature of
4849 the GCC compiler (Global Register Variables) to share the data: we
4850 place a pointer (gd) to the global data into a register which we
4851 reserve for this purpose.
4853 When choosing a register for such a purpose we are restricted by the
4854 relevant (E)ABI specifications for the current architecture, and by
4855 GCC's implementation.
4857 For PowerPC, the following registers have specific use:
4859 R2: reserved for system use
4860 R3-R4: parameter passing and return values
4861 R5-R10: parameter passing
4862 R13: small data area pointer
4866 (U-Boot also uses R12 as internal GOT pointer. r12
4867 is a volatile register so r12 needs to be reset when
4868 going back and forth between asm and C)
4870 ==> U-Boot will use R2 to hold a pointer to the global data
4872 Note: on PPC, we could use a static initializer (since the
4873 address of the global data structure is known at compile time),
4874 but it turned out that reserving a register results in somewhat
4875 smaller code - although the code savings are not that big (on
4876 average for all boards 752 bytes for the whole U-Boot image,
4877 624 text + 127 data).
4879 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4880 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4882 ==> U-Boot will use P3 to hold a pointer to the global data
4884 On ARM, the following registers are used:
4886 R0: function argument word/integer result
4887 R1-R3: function argument word
4889 R10: stack limit (used only if stack checking if enabled)
4890 R11: argument (frame) pointer
4891 R12: temporary workspace
4894 R15: program counter
4896 ==> U-Boot will use R8 to hold a pointer to the global data
4898 On Nios II, the ABI is documented here:
4899 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4901 ==> U-Boot will use gp to hold a pointer to the global data
4903 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4904 to access small data sections, so gp is free.
4906 On NDS32, the following registers are used:
4908 R0-R1: argument/return
4910 R15: temporary register for assembler
4911 R16: trampoline register
4912 R28: frame pointer (FP)
4913 R29: global pointer (GP)
4914 R30: link register (LP)
4915 R31: stack pointer (SP)
4916 PC: program counter (PC)
4918 ==> U-Boot will use R10 to hold a pointer to the global data
4920 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4921 or current versions of GCC may "optimize" the code too much.
4926 U-Boot runs in system state and uses physical addresses, i.e. the
4927 MMU is not used either for address mapping nor for memory protection.
4929 The available memory is mapped to fixed addresses using the memory
4930 controller. In this process, a contiguous block is formed for each
4931 memory type (Flash, SDRAM, SRAM), even when it consists of several
4932 physical memory banks.
4934 U-Boot is installed in the first 128 kB of the first Flash bank (on
4935 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4936 booting and sizing and initializing DRAM, the code relocates itself
4937 to the upper end of DRAM. Immediately below the U-Boot code some
4938 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4939 configuration setting]. Below that, a structure with global Board
4940 Info data is placed, followed by the stack (growing downward).
4942 Additionally, some exception handler code is copied to the low 8 kB
4943 of DRAM (0x00000000 ... 0x00001FFF).
4945 So a typical memory configuration with 16 MB of DRAM could look like
4948 0x0000 0000 Exception Vector code
4951 0x0000 2000 Free for Application Use
4957 0x00FB FF20 Monitor Stack (Growing downward)
4958 0x00FB FFAC Board Info Data and permanent copy of global data
4959 0x00FC 0000 Malloc Arena
4962 0x00FE 0000 RAM Copy of Monitor Code
4963 ... eventually: LCD or video framebuffer
4964 ... eventually: pRAM (Protected RAM - unchanged by reset)
4965 0x00FF FFFF [End of RAM]
4968 System Initialization:
4969 ----------------------
4971 In the reset configuration, U-Boot starts at the reset entry point
4972 (on most PowerPC systems at address 0x00000100). Because of the reset
4973 configuration for CS0# this is a mirror of the onboard Flash memory.
4974 To be able to re-map memory U-Boot then jumps to its link address.
4975 To be able to implement the initialization code in C, a (small!)
4976 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4977 which provide such a feature like MPC8xx or MPC8260), or in a locked
4978 part of the data cache. After that, U-Boot initializes the CPU core,
4979 the caches and the SIU.
4981 Next, all (potentially) available memory banks are mapped using a
4982 preliminary mapping. For example, we put them on 512 MB boundaries
4983 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4984 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4985 programmed for SDRAM access. Using the temporary configuration, a
4986 simple memory test is run that determines the size of the SDRAM
4989 When there is more than one SDRAM bank, and the banks are of
4990 different size, the largest is mapped first. For equal size, the first
4991 bank (CS2#) is mapped first. The first mapping is always for address
4992 0x00000000, with any additional banks following immediately to create
4993 contiguous memory starting from 0.
4995 Then, the monitor installs itself at the upper end of the SDRAM area
4996 and allocates memory for use by malloc() and for the global Board
4997 Info data; also, the exception vector code is copied to the low RAM
4998 pages, and the final stack is set up.
5000 Only after this relocation will you have a "normal" C environment;
5001 until that you are restricted in several ways, mostly because you are
5002 running from ROM, and because the code will have to be relocated to a
5006 U-Boot Porting Guide:
5007 ----------------------
5009 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5013 int main(int argc, char *argv[])
5015 sighandler_t no_more_time;
5017 signal(SIGALRM, no_more_time);
5018 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5020 if (available_money > available_manpower) {
5021 Pay consultant to port U-Boot;
5025 Download latest U-Boot source;
5027 Subscribe to u-boot mailing list;
5030 email("Hi, I am new to U-Boot, how do I get started?");
5033 Read the README file in the top level directory;
5034 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5035 Read applicable doc/*.README;
5036 Read the source, Luke;
5037 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5040 if (available_money > toLocalCurrency ($2500))
5043 Add a lot of aggravation and time;
5045 if (a similar board exists) { /* hopefully... */
5046 cp -a board/<similar> board/<myboard>
5047 cp include/configs/<similar>.h include/configs/<myboard>.h
5049 Create your own board support subdirectory;
5050 Create your own board include/configs/<myboard>.h file;
5052 Edit new board/<myboard> files
5053 Edit new include/configs/<myboard>.h
5058 Add / modify source code;
5062 email("Hi, I am having problems...");
5064 Send patch file to the U-Boot email list;
5065 if (reasonable critiques)
5066 Incorporate improvements from email list code review;
5068 Defend code as written;
5074 void no_more_time (int sig)
5083 All contributions to U-Boot should conform to the Linux kernel
5084 coding style; see the file "Documentation/CodingStyle" and the script
5085 "scripts/Lindent" in your Linux kernel source directory.
5087 Source files originating from a different project (for example the
5088 MTD subsystem) are generally exempt from these guidelines and are not
5089 reformated to ease subsequent migration to newer versions of those
5092 Please note that U-Boot is implemented in C (and to some small parts in
5093 Assembler); no C++ is used, so please do not use C++ style comments (//)
5096 Please also stick to the following formatting rules:
5097 - remove any trailing white space
5098 - use TAB characters for indentation and vertical alignment, not spaces
5099 - make sure NOT to use DOS '\r\n' line feeds
5100 - do not add more than 2 consecutive empty lines to source files
5101 - do not add trailing empty lines to source files
5103 Submissions which do not conform to the standards may be returned
5104 with a request to reformat the changes.
5110 Since the number of patches for U-Boot is growing, we need to
5111 establish some rules. Submissions which do not conform to these rules
5112 may be rejected, even when they contain important and valuable stuff.
5114 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5116 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5117 see http://lists.denx.de/mailman/listinfo/u-boot
5119 When you send a patch, please include the following information with
5122 * For bug fixes: a description of the bug and how your patch fixes
5123 this bug. Please try to include a way of demonstrating that the
5124 patch actually fixes something.
5126 * For new features: a description of the feature and your
5129 * A CHANGELOG entry as plaintext (separate from the patch)
5131 * For major contributions, your entry to the CREDITS file
5133 * When you add support for a new board, don't forget to add this
5134 board to the MAINTAINERS file, too.
5136 * If your patch adds new configuration options, don't forget to
5137 document these in the README file.
5139 * The patch itself. If you are using git (which is *strongly*
5140 recommended) you can easily generate the patch using the
5141 "git format-patch". If you then use "git send-email" to send it to
5142 the U-Boot mailing list, you will avoid most of the common problems
5143 with some other mail clients.
5145 If you cannot use git, use "diff -purN OLD NEW". If your version of
5146 diff does not support these options, then get the latest version of
5149 The current directory when running this command shall be the parent
5150 directory of the U-Boot source tree (i. e. please make sure that
5151 your patch includes sufficient directory information for the
5154 We prefer patches as plain text. MIME attachments are discouraged,
5155 and compressed attachments must not be used.
5157 * If one logical set of modifications affects or creates several
5158 files, all these changes shall be submitted in a SINGLE patch file.
5160 * Changesets that contain different, unrelated modifications shall be
5161 submitted as SEPARATE patches, one patch per changeset.
5166 * Before sending the patch, run the MAKEALL script on your patched
5167 source tree and make sure that no errors or warnings are reported
5168 for any of the boards.
5170 * Keep your modifications to the necessary minimum: A patch
5171 containing several unrelated changes or arbitrary reformats will be
5172 returned with a request to re-formatting / split it.
5174 * If you modify existing code, make sure that your new code does not
5175 add to the memory footprint of the code ;-) Small is beautiful!
5176 When adding new features, these should compile conditionally only
5177 (using #ifdef), and the resulting code with the new feature
5178 disabled must not need more memory than the old code without your
5181 * Remember that there is a size limit of 100 kB per message on the
5182 u-boot mailing list. Bigger patches will be moderated. If they are
5183 reasonable and not too big, they will be acknowledged. But patches
5184 bigger than the size limit should be avoided.