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
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 CONFIG_ARM_ERRATA_716044
489 CONFIG_ARM_ERRATA_742230
490 CONFIG_ARM_ERRATA_743622
491 CONFIG_ARM_ERRATA_751472
493 If set, the workarounds for these ARM errata are applied early
494 during U-Boot startup. Note that these options force the
495 workarounds to be applied; no CPU-type/version detection
496 exists, unlike the similar options in the Linux kernel. Do not
497 set these options unless they apply!
499 - Linux Kernel Interface:
502 U-Boot stores all clock information in Hz
503 internally. For binary compatibility with older Linux
504 kernels (which expect the clocks passed in the
505 bd_info data to be in MHz) the environment variable
506 "clocks_in_mhz" can be defined so that U-Boot
507 converts clock data to MHZ before passing it to the
509 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
510 "clocks_in_mhz=1" is automatically included in the
513 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
515 When transferring memsize parameter to linux, some versions
516 expect it to be in bytes, others in MB.
517 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
521 New kernel versions are expecting firmware settings to be
522 passed using flattened device trees (based on open firmware
526 * New libfdt-based support
527 * Adds the "fdt" command
528 * The bootm command automatically updates the fdt
530 OF_CPU - The proper name of the cpus node (only required for
531 MPC512X and MPC5xxx based boards).
532 OF_SOC - The proper name of the soc node (only required for
533 MPC512X and MPC5xxx based boards).
534 OF_TBCLK - The timebase frequency.
535 OF_STDOUT_PATH - The path to the console device
537 boards with QUICC Engines require OF_QE to set UCC MAC
540 CONFIG_OF_BOARD_SETUP
542 Board code has addition modification that it wants to make
543 to the flat device tree before handing it off to the kernel
547 This define fills in the correct boot CPU in the boot
548 param header, the default value is zero if undefined.
552 U-Boot can detect if an IDE device is present or not.
553 If not, and this new config option is activated, U-Boot
554 removes the ATA node from the DTS before booting Linux,
555 so the Linux IDE driver does not probe the device and
556 crash. This is needed for buggy hardware (uc101) where
557 no pull down resistor is connected to the signal IDE5V_DD7.
559 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
561 This setting is mandatory for all boards that have only one
562 machine type and must be used to specify the machine type
563 number as it appears in the ARM machine registry
564 (see http://www.arm.linux.org.uk/developer/machines/).
565 Only boards that have multiple machine types supported
566 in a single configuration file and the machine type is
567 runtime discoverable, do not have to use this setting.
569 - vxWorks boot parameters:
571 bootvx constructs a valid bootline using the following
572 environments variables: bootfile, ipaddr, serverip, hostname.
573 It loads the vxWorks image pointed bootfile.
575 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
576 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
577 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
578 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
580 CONFIG_SYS_VXWORKS_ADD_PARAMS
582 Add it at the end of the bootline. E.g "u=username pw=secret"
584 Note: If a "bootargs" environment is defined, it will overwride
585 the defaults discussed just above.
587 - Cache Configuration:
588 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
589 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
590 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
592 - Cache Configuration for ARM:
593 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
595 CONFIG_SYS_PL310_BASE - Physical base address of PL310
596 controller register space
601 Define this if you want support for Amba PrimeCell PL010 UARTs.
605 Define this if you want support for Amba PrimeCell PL011 UARTs.
609 If you have Amba PrimeCell PL011 UARTs, set this variable to
610 the clock speed of the UARTs.
614 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
615 define this to a list of base addresses for each (supported)
616 port. See e.g. include/configs/versatile.h
618 CONFIG_PL011_SERIAL_RLCR
620 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
621 have separate receive and transmit line control registers. Set
622 this variable to initialize the extra register.
624 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
626 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
627 boot loader that has already initialized the UART. Define this
628 variable to flush the UART at init time.
632 Depending on board, define exactly one serial port
633 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
634 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
635 console by defining CONFIG_8xx_CONS_NONE
637 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
638 port routines must be defined elsewhere
639 (i.e. serial_init(), serial_getc(), ...)
642 Enables console device for a color framebuffer. Needs following
643 defines (cf. smiLynxEM, i8042)
644 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
646 VIDEO_HW_RECTFILL graphic chip supports
649 VIDEO_HW_BITBLT graphic chip supports
650 bit-blit (cf. smiLynxEM)
651 VIDEO_VISIBLE_COLS visible pixel columns
653 VIDEO_VISIBLE_ROWS visible pixel rows
654 VIDEO_PIXEL_SIZE bytes per pixel
655 VIDEO_DATA_FORMAT graphic data format
656 (0-5, cf. cfb_console.c)
657 VIDEO_FB_ADRS framebuffer address
658 VIDEO_KBD_INIT_FCT keyboard int fct
659 (i.e. i8042_kbd_init())
660 VIDEO_TSTC_FCT test char fct
662 VIDEO_GETC_FCT get char fct
664 CONFIG_CONSOLE_CURSOR cursor drawing on/off
665 (requires blink timer
667 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
668 CONFIG_CONSOLE_TIME display time/date info in
670 (requires CONFIG_CMD_DATE)
671 CONFIG_VIDEO_LOGO display Linux logo in
673 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
674 linux_logo.h for logo.
675 Requires CONFIG_VIDEO_LOGO
676 CONFIG_CONSOLE_EXTRA_INFO
677 additional board info beside
680 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
681 a limited number of ANSI escape sequences (cursor control,
682 erase functions and limited graphics rendition control).
684 When CONFIG_CFB_CONSOLE is defined, video console is
685 default i/o. Serial console can be forced with
686 environment 'console=serial'.
688 When CONFIG_SILENT_CONSOLE is defined, all console
689 messages (by U-Boot and Linux!) can be silenced with
690 the "silent" environment variable. See
691 doc/README.silent for more information.
694 CONFIG_BAUDRATE - in bps
695 Select one of the baudrates listed in
696 CONFIG_SYS_BAUDRATE_TABLE, see below.
697 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
699 - Console Rx buffer length
700 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
701 the maximum receive buffer length for the SMC.
702 This option is actual only for 82xx and 8xx possible.
703 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
704 must be defined, to setup the maximum idle timeout for
707 - Pre-Console Buffer:
708 Prior to the console being initialised (i.e. serial UART
709 initialised etc) all console output is silently discarded.
710 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
711 buffer any console messages prior to the console being
712 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
713 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
714 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
715 bytes are output before the console is initialised, the
716 earlier bytes are discarded.
718 'Sane' compilers will generate smaller code if
719 CONFIG_PRE_CON_BUF_SZ is a power of 2
721 - Safe printf() functions
722 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
723 the printf() functions. These are defined in
724 include/vsprintf.h and include snprintf(), vsnprintf() and
725 so on. Code size increase is approximately 300-500 bytes.
726 If this option is not given then these functions will
727 silently discard their buffer size argument - this means
728 you are not getting any overflow checking in this case.
730 - Boot Delay: CONFIG_BOOTDELAY - in seconds
731 Delay before automatically booting the default image;
732 set to -1 to disable autoboot.
733 set to -2 to autoboot with no delay and not check for abort
734 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
736 See doc/README.autoboot for these options that
737 work with CONFIG_BOOTDELAY. None are required.
738 CONFIG_BOOT_RETRY_TIME
739 CONFIG_BOOT_RETRY_MIN
740 CONFIG_AUTOBOOT_KEYED
741 CONFIG_AUTOBOOT_PROMPT
742 CONFIG_AUTOBOOT_DELAY_STR
743 CONFIG_AUTOBOOT_STOP_STR
744 CONFIG_AUTOBOOT_DELAY_STR2
745 CONFIG_AUTOBOOT_STOP_STR2
746 CONFIG_ZERO_BOOTDELAY_CHECK
747 CONFIG_RESET_TO_RETRY
751 Only needed when CONFIG_BOOTDELAY is enabled;
752 define a command string that is automatically executed
753 when no character is read on the console interface
754 within "Boot Delay" after reset.
757 This can be used to pass arguments to the bootm
758 command. The value of CONFIG_BOOTARGS goes into the
759 environment value "bootargs".
761 CONFIG_RAMBOOT and CONFIG_NFSBOOT
762 The value of these goes into the environment as
763 "ramboot" and "nfsboot" respectively, and can be used
764 as a convenience, when switching between booting from
770 When this option is #defined, the existence of the
771 environment variable "preboot" will be checked
772 immediately before starting the CONFIG_BOOTDELAY
773 countdown and/or running the auto-boot command resp.
774 entering interactive mode.
776 This feature is especially useful when "preboot" is
777 automatically generated or modified. For an example
778 see the LWMON board specific code: here "preboot" is
779 modified when the user holds down a certain
780 combination of keys on the (special) keyboard when
783 - Serial Download Echo Mode:
785 If defined to 1, all characters received during a
786 serial download (using the "loads" command) are
787 echoed back. This might be needed by some terminal
788 emulations (like "cu"), but may as well just take
789 time on others. This setting #define's the initial
790 value of the "loads_echo" environment variable.
792 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
794 Select one of the baudrates listed in
795 CONFIG_SYS_BAUDRATE_TABLE, see below.
798 Monitor commands can be included or excluded
799 from the build by using the #include files
800 <config_cmd_all.h> and #undef'ing unwanted
801 commands, or using <config_cmd_default.h>
802 and augmenting with additional #define's
805 The default command configuration includes all commands
806 except those marked below with a "*".
808 CONFIG_CMD_ASKENV * ask for env variable
809 CONFIG_CMD_BDI bdinfo
810 CONFIG_CMD_BEDBUG * Include BedBug Debugger
811 CONFIG_CMD_BMP * BMP support
812 CONFIG_CMD_BSP * Board specific commands
813 CONFIG_CMD_BOOTD bootd
814 CONFIG_CMD_CACHE * icache, dcache
815 CONFIG_CMD_CONSOLE coninfo
816 CONFIG_CMD_CRC32 * crc32
817 CONFIG_CMD_DATE * support for RTC, date/time...
818 CONFIG_CMD_DHCP * DHCP support
819 CONFIG_CMD_DIAG * Diagnostics
820 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
821 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
822 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
823 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
824 CONFIG_CMD_DTT * Digital Therm and Thermostat
825 CONFIG_CMD_ECHO echo arguments
826 CONFIG_CMD_EDITENV edit env variable
827 CONFIG_CMD_EEPROM * EEPROM read/write support
828 CONFIG_CMD_ELF * bootelf, bootvx
829 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
830 CONFIG_CMD_ENV_FLAGS * display details about env flags
831 CONFIG_CMD_EXPORTENV * export the environment
832 CONFIG_CMD_EXT2 * ext2 command support
833 CONFIG_CMD_EXT4 * ext4 command support
834 CONFIG_CMD_SAVEENV saveenv
835 CONFIG_CMD_FDC * Floppy Disk Support
836 CONFIG_CMD_FAT * FAT command support
837 CONFIG_CMD_FDOS * Dos diskette Support
838 CONFIG_CMD_FLASH flinfo, erase, protect
839 CONFIG_CMD_FPGA FPGA device initialization support
840 CONFIG_CMD_GETTIME * Get time since boot
841 CONFIG_CMD_GO * the 'go' command (exec code)
842 CONFIG_CMD_GREPENV * search environment
843 CONFIG_CMD_HASH * calculate hash / digest
844 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
845 CONFIG_CMD_I2C * I2C serial bus support
846 CONFIG_CMD_IDE * IDE harddisk support
847 CONFIG_CMD_IMI iminfo
848 CONFIG_CMD_IMLS List all images found in NOR flash
849 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
850 CONFIG_CMD_IMMAP * IMMR dump support
851 CONFIG_CMD_IMPORTENV * import an environment
852 CONFIG_CMD_INI * import data from an ini file into the env
853 CONFIG_CMD_IRQ * irqinfo
854 CONFIG_CMD_ITEST Integer/string test of 2 values
855 CONFIG_CMD_JFFS2 * JFFS2 Support
856 CONFIG_CMD_KGDB * kgdb
857 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
858 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
860 CONFIG_CMD_LOADB loadb
861 CONFIG_CMD_LOADS loads
862 CONFIG_CMD_MD5SUM print md5 message digest
863 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
864 CONFIG_CMD_MEMINFO * Display detailed memory information
865 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
867 CONFIG_CMD_MEMTEST mtest
868 CONFIG_CMD_MISC Misc functions like sleep etc
869 CONFIG_CMD_MMC * MMC memory mapped support
870 CONFIG_CMD_MII * MII utility commands
871 CONFIG_CMD_MTDPARTS * MTD partition support
872 CONFIG_CMD_NAND * NAND support
873 CONFIG_CMD_NET bootp, tftpboot, rarpboot
874 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
875 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
876 CONFIG_CMD_PCI * pciinfo
877 CONFIG_CMD_PCMCIA * PCMCIA support
878 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
880 CONFIG_CMD_PORTIO * Port I/O
881 CONFIG_CMD_READ * Read raw data from partition
882 CONFIG_CMD_REGINFO * Register dump
883 CONFIG_CMD_RUN run command in env variable
884 CONFIG_CMD_SANDBOX * sb command to access sandbox features
885 CONFIG_CMD_SAVES * save S record dump
886 CONFIG_CMD_SCSI * SCSI Support
887 CONFIG_CMD_SDRAM * print SDRAM configuration information
888 (requires CONFIG_CMD_I2C)
889 CONFIG_CMD_SETGETDCR Support for DCR Register access
891 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
892 CONFIG_CMD_SHA1SUM print sha1 memory digest
893 (requires CONFIG_CMD_MEMORY)
894 CONFIG_CMD_SOURCE "source" command Support
895 CONFIG_CMD_SPI * SPI serial bus support
896 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
897 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
898 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
899 CONFIG_CMD_TIMER * access to the system tick timer
900 CONFIG_CMD_USB * USB support
901 CONFIG_CMD_CDP * Cisco Discover Protocol support
902 CONFIG_CMD_MFSL * Microblaze FSL support
905 EXAMPLE: If you want all functions except of network
906 support you can write:
908 #include "config_cmd_all.h"
909 #undef CONFIG_CMD_NET
912 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
914 Note: Don't enable the "icache" and "dcache" commands
915 (configuration option CONFIG_CMD_CACHE) unless you know
916 what you (and your U-Boot users) are doing. Data
917 cache cannot be enabled on systems like the 8xx or
918 8260 (where accesses to the IMMR region must be
919 uncached), and it cannot be disabled on all other
920 systems where we (mis-) use the data cache to hold an
921 initial stack and some data.
924 XXX - this list needs to get updated!
928 If this variable is defined, U-Boot will use a device tree
929 to configure its devices, instead of relying on statically
930 compiled #defines in the board file. This option is
931 experimental and only available on a few boards. The device
932 tree is available in the global data as gd->fdt_blob.
934 U-Boot needs to get its device tree from somewhere. This can
935 be done using one of the two options below:
938 If this variable is defined, U-Boot will embed a device tree
939 binary in its image. This device tree file should be in the
940 board directory and called <soc>-<board>.dts. The binary file
941 is then picked up in board_init_f() and made available through
942 the global data structure as gd->blob.
945 If this variable is defined, U-Boot will build a device tree
946 binary. It will be called u-boot.dtb. Architecture-specific
947 code will locate it at run-time. Generally this works by:
949 cat u-boot.bin u-boot.dtb >image.bin
951 and in fact, U-Boot does this for you, creating a file called
952 u-boot-dtb.bin which is useful in the common case. You can
953 still use the individual files if you need something more
958 If this variable is defined, it enables watchdog
959 support for the SoC. There must be support in the SoC
960 specific code for a watchdog. For the 8xx and 8260
961 CPUs, the SIU Watchdog feature is enabled in the SYPCR
962 register. When supported for a specific SoC is
963 available, then no further board specific code should
967 When using a watchdog circuitry external to the used
968 SoC, then define this variable and provide board
969 specific code for the "hw_watchdog_reset" function.
972 CONFIG_VERSION_VARIABLE
973 If this variable is defined, an environment variable
974 named "ver" is created by U-Boot showing the U-Boot
975 version as printed by the "version" command.
976 Any change to this variable will be reverted at the
981 When CONFIG_CMD_DATE is selected, the type of the RTC
982 has to be selected, too. Define exactly one of the
985 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
986 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
987 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
988 CONFIG_RTC_MC146818 - use MC146818 RTC
989 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
990 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
991 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
992 CONFIG_RTC_DS164x - use Dallas DS164x RTC
993 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
994 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
995 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
996 CONFIG_SYS_RV3029_TCR - enable trickle charger on
999 Note that if the RTC uses I2C, then the I2C interface
1000 must also be configured. See I2C Support, below.
1003 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1004 CONFIG_PCA953X_INFO - enable pca953x info command
1006 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1007 chip-ngpio pairs that tell the PCA953X driver the number of
1008 pins supported by a particular chip.
1010 Note that if the GPIO device uses I2C, then the I2C interface
1011 must also be configured. See I2C Support, below.
1013 - Timestamp Support:
1015 When CONFIG_TIMESTAMP is selected, the timestamp
1016 (date and time) of an image is printed by image
1017 commands like bootm or iminfo. This option is
1018 automatically enabled when you select CONFIG_CMD_DATE .
1020 - Partition Labels (disklabels) Supported:
1021 Zero or more of the following:
1022 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1023 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1024 Intel architecture, USB sticks, etc.
1025 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1026 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1027 bootloader. Note 2TB partition limit; see
1029 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1031 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1032 CONFIG_CMD_SCSI) you must configure support for at
1033 least one non-MTD partition type as well.
1036 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1037 board configurations files but used nowhere!
1039 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1040 be performed by calling the function
1041 ide_set_reset(int reset)
1042 which has to be defined in a board specific file
1047 Set this to enable ATAPI support.
1052 Set this to enable support for disks larger than 137GB
1053 Also look at CONFIG_SYS_64BIT_LBA.
1054 Whithout these , LBA48 support uses 32bit variables and will 'only'
1055 support disks up to 2.1TB.
1057 CONFIG_SYS_64BIT_LBA:
1058 When enabled, makes the IDE subsystem use 64bit sector addresses.
1062 At the moment only there is only support for the
1063 SYM53C8XX SCSI controller; define
1064 CONFIG_SCSI_SYM53C8XX to enable it.
1066 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1067 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1068 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1069 maximum numbers of LUNs, SCSI ID's and target
1071 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1073 The environment variable 'scsidevs' is set to the number of
1074 SCSI devices found during the last scan.
1076 - NETWORK Support (PCI):
1078 Support for Intel 8254x/8257x gigabit chips.
1081 Utility code for direct access to the SPI bus on Intel 8257x.
1082 This does not do anything useful unless you set at least one
1083 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1085 CONFIG_E1000_SPI_GENERIC
1086 Allow generic access to the SPI bus on the Intel 8257x, for
1087 example with the "sspi" command.
1090 Management command for E1000 devices. When used on devices
1091 with SPI support you can reprogram the EEPROM from U-Boot.
1093 CONFIG_E1000_FALLBACK_MAC
1094 default MAC for empty EEPROM after production.
1097 Support for Intel 82557/82559/82559ER chips.
1098 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1099 write routine for first time initialisation.
1102 Support for Digital 2114x chips.
1103 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1104 modem chip initialisation (KS8761/QS6611).
1107 Support for National dp83815 chips.
1110 Support for National dp8382[01] gigabit chips.
1112 - NETWORK Support (other):
1114 CONFIG_DRIVER_AT91EMAC
1115 Support for AT91RM9200 EMAC.
1118 Define this to use reduced MII inteface
1120 CONFIG_DRIVER_AT91EMAC_QUIET
1121 If this defined, the driver is quiet.
1122 The driver doen't show link status messages.
1124 CONFIG_CALXEDA_XGMAC
1125 Support for the Calxeda XGMAC device
1128 Support for SMSC's LAN91C96 chips.
1130 CONFIG_LAN91C96_BASE
1131 Define this to hold the physical address
1132 of the LAN91C96's I/O space
1134 CONFIG_LAN91C96_USE_32_BIT
1135 Define this to enable 32 bit addressing
1138 Support for SMSC's LAN91C111 chip
1140 CONFIG_SMC91111_BASE
1141 Define this to hold the physical address
1142 of the device (I/O space)
1144 CONFIG_SMC_USE_32_BIT
1145 Define this if data bus is 32 bits
1147 CONFIG_SMC_USE_IOFUNCS
1148 Define this to use i/o functions instead of macros
1149 (some hardware wont work with macros)
1151 CONFIG_DRIVER_TI_EMAC
1152 Support for davinci emac
1154 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1155 Define this if you have more then 3 PHYs.
1158 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1160 CONFIG_FTGMAC100_EGIGA
1161 Define this to use GE link update with gigabit PHY.
1162 Define this if FTGMAC100 is connected to gigabit PHY.
1163 If your system has 10/100 PHY only, it might not occur
1164 wrong behavior. Because PHY usually return timeout or
1165 useless data when polling gigabit status and gigabit
1166 control registers. This behavior won't affect the
1167 correctnessof 10/100 link speed update.
1170 Support for SMSC's LAN911x and LAN921x chips
1173 Define this to hold the physical address
1174 of the device (I/O space)
1176 CONFIG_SMC911X_32_BIT
1177 Define this if data bus is 32 bits
1179 CONFIG_SMC911X_16_BIT
1180 Define this if data bus is 16 bits. If your processor
1181 automatically converts one 32 bit word to two 16 bit
1182 words you may also try CONFIG_SMC911X_32_BIT.
1185 Support for Renesas on-chip Ethernet controller
1187 CONFIG_SH_ETHER_USE_PORT
1188 Define the number of ports to be used
1190 CONFIG_SH_ETHER_PHY_ADDR
1191 Define the ETH PHY's address
1193 CONFIG_SH_ETHER_CACHE_WRITEBACK
1194 If this option is set, the driver enables cache flush.
1197 CONFIG_GENERIC_LPC_TPM
1198 Support for generic parallel port TPM devices. Only one device
1199 per system is supported at this time.
1201 CONFIG_TPM_TIS_BASE_ADDRESS
1202 Base address where the generic TPM device is mapped
1203 to. Contemporary x86 systems usually map it at
1207 At the moment only the UHCI host controller is
1208 supported (PIP405, MIP405, MPC5200); define
1209 CONFIG_USB_UHCI to enable it.
1210 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1211 and define CONFIG_USB_STORAGE to enable the USB
1214 Supported are USB Keyboards and USB Floppy drives
1216 MPC5200 USB requires additional defines:
1218 for 528 MHz Clock: 0x0001bbbb
1222 for differential drivers: 0x00001000
1223 for single ended drivers: 0x00005000
1224 for differential drivers on PSC3: 0x00000100
1225 for single ended drivers on PSC3: 0x00004100
1226 CONFIG_SYS_USB_EVENT_POLL
1227 May be defined to allow interrupt polling
1228 instead of using asynchronous interrupts
1230 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1231 txfilltuning field in the EHCI controller on reset.
1234 Define the below if you wish to use the USB console.
1235 Once firmware is rebuilt from a serial console issue the
1236 command "setenv stdin usbtty; setenv stdout usbtty" and
1237 attach your USB cable. The Unix command "dmesg" should print
1238 it has found a new device. The environment variable usbtty
1239 can be set to gserial or cdc_acm to enable your device to
1240 appear to a USB host as a Linux gserial device or a
1241 Common Device Class Abstract Control Model serial device.
1242 If you select usbtty = gserial you should be able to enumerate
1244 # modprobe usbserial vendor=0xVendorID product=0xProductID
1245 else if using cdc_acm, simply setting the environment
1246 variable usbtty to be cdc_acm should suffice. The following
1247 might be defined in YourBoardName.h
1250 Define this to build a UDC device
1253 Define this to have a tty type of device available to
1254 talk to the UDC device
1257 Define this to enable the high speed support for usb
1258 device and usbtty. If this feature is enabled, a routine
1259 int is_usbd_high_speed(void)
1260 also needs to be defined by the driver to dynamically poll
1261 whether the enumeration has succeded at high speed or full
1264 CONFIG_SYS_CONSOLE_IS_IN_ENV
1265 Define this if you want stdin, stdout &/or stderr to
1269 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1270 Derive USB clock from external clock "blah"
1271 - CONFIG_SYS_USB_EXTC_CLK 0x02
1273 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1274 Derive USB clock from brgclk
1275 - CONFIG_SYS_USB_BRG_CLK 0x04
1277 If you have a USB-IF assigned VendorID then you may wish to
1278 define your own vendor specific values either in BoardName.h
1279 or directly in usbd_vendor_info.h. If you don't define
1280 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1281 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1282 should pretend to be a Linux device to it's target host.
1284 CONFIG_USBD_MANUFACTURER
1285 Define this string as the name of your company for
1286 - CONFIG_USBD_MANUFACTURER "my company"
1288 CONFIG_USBD_PRODUCT_NAME
1289 Define this string as the name of your product
1290 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1292 CONFIG_USBD_VENDORID
1293 Define this as your assigned Vendor ID from the USB
1294 Implementors Forum. This *must* be a genuine Vendor ID
1295 to avoid polluting the USB namespace.
1296 - CONFIG_USBD_VENDORID 0xFFFF
1298 CONFIG_USBD_PRODUCTID
1299 Define this as the unique Product ID
1301 - CONFIG_USBD_PRODUCTID 0xFFFF
1303 - ULPI Layer Support:
1304 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1305 the generic ULPI layer. The generic layer accesses the ULPI PHY
1306 via the platform viewport, so you need both the genric layer and
1307 the viewport enabled. Currently only Chipidea/ARC based
1308 viewport is supported.
1309 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1310 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1311 If your ULPI phy needs a different reference clock than the
1312 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1313 the appropriate value in Hz.
1316 The MMC controller on the Intel PXA is supported. To
1317 enable this define CONFIG_MMC. The MMC can be
1318 accessed from the boot prompt by mapping the device
1319 to physical memory similar to flash. Command line is
1320 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1321 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1324 Support for Renesas on-chip MMCIF controller
1326 CONFIG_SH_MMCIF_ADDR
1327 Define the base address of MMCIF registers
1330 Define the clock frequency for MMCIF
1332 - Journaling Flash filesystem support:
1333 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1334 CONFIG_JFFS2_NAND_DEV
1335 Define these for a default partition on a NAND device
1337 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1338 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1339 Define these for a default partition on a NOR device
1341 CONFIG_SYS_JFFS_CUSTOM_PART
1342 Define this to create an own partition. You have to provide a
1343 function struct part_info* jffs2_part_info(int part_num)
1345 If you define only one JFFS2 partition you may also want to
1346 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1347 to disable the command chpart. This is the default when you
1348 have not defined a custom partition
1350 - FAT(File Allocation Table) filesystem write function support:
1353 Define this to enable support for saving memory data as a
1354 file in FAT formatted partition.
1356 This will also enable the command "fatwrite" enabling the
1357 user to write files to FAT.
1359 CBFS (Coreboot Filesystem) support
1362 Define this to enable support for reading from a Coreboot
1363 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1369 Define this to enable standard (PC-Style) keyboard
1373 Standard PC keyboard driver with US (is default) and
1374 GERMAN key layout (switch via environment 'keymap=de') support.
1375 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1376 for cfb_console. Supports cursor blinking.
1381 Define this to enable video support (for output to
1384 CONFIG_VIDEO_CT69000
1386 Enable Chips & Technologies 69000 Video chip
1388 CONFIG_VIDEO_SMI_LYNXEM
1389 Enable Silicon Motion SMI 712/710/810 Video chip. The
1390 video output is selected via environment 'videoout'
1391 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1394 For the CT69000 and SMI_LYNXEM drivers, videomode is
1395 selected via environment 'videomode'. Two different ways
1397 - "videomode=num" 'num' is a standard LiLo mode numbers.
1398 Following standard modes are supported (* is default):
1400 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1401 -------------+---------------------------------------------
1402 8 bits | 0x301* 0x303 0x305 0x161 0x307
1403 15 bits | 0x310 0x313 0x316 0x162 0x319
1404 16 bits | 0x311 0x314 0x317 0x163 0x31A
1405 24 bits | 0x312 0x315 0x318 ? 0x31B
1406 -------------+---------------------------------------------
1407 (i.e. setenv videomode 317; saveenv; reset;)
1409 - "videomode=bootargs" all the video parameters are parsed
1410 from the bootargs. (See drivers/video/videomodes.c)
1413 CONFIG_VIDEO_SED13806
1414 Enable Epson SED13806 driver. This driver supports 8bpp
1415 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1416 or CONFIG_VIDEO_SED13806_16BPP
1419 Enable the Freescale DIU video driver. Reference boards for
1420 SOCs that have a DIU should define this macro to enable DIU
1421 support, and should also define these other macros:
1427 CONFIG_VIDEO_SW_CURSOR
1428 CONFIG_VGA_AS_SINGLE_DEVICE
1430 CONFIG_VIDEO_BMP_LOGO
1432 The DIU driver will look for the 'video-mode' environment
1433 variable, and if defined, enable the DIU as a console during
1434 boot. See the documentation file README.video for a
1435 description of this variable.
1439 Enable the VGA video / BIOS for x86. The alternative if you
1440 are using coreboot is to use the coreboot frame buffer
1447 Define this to enable a custom keyboard support.
1448 This simply calls drv_keyboard_init() which must be
1449 defined in your board-specific files.
1450 The only board using this so far is RBC823.
1452 - LCD Support: CONFIG_LCD
1454 Define this to enable LCD support (for output to LCD
1455 display); also select one of the supported displays
1456 by defining one of these:
1460 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1462 CONFIG_NEC_NL6448AC33:
1464 NEC NL6448AC33-18. Active, color, single scan.
1466 CONFIG_NEC_NL6448BC20
1468 NEC NL6448BC20-08. 6.5", 640x480.
1469 Active, color, single scan.
1471 CONFIG_NEC_NL6448BC33_54
1473 NEC NL6448BC33-54. 10.4", 640x480.
1474 Active, color, single scan.
1478 Sharp 320x240. Active, color, single scan.
1479 It isn't 16x9, and I am not sure what it is.
1481 CONFIG_SHARP_LQ64D341
1483 Sharp LQ64D341 display, 640x480.
1484 Active, color, single scan.
1488 HLD1045 display, 640x480.
1489 Active, color, single scan.
1493 Optrex CBL50840-2 NF-FW 99 22 M5
1495 Hitachi LMG6912RPFC-00T
1499 320x240. Black & white.
1501 Normally display is black on white background; define
1502 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1504 CONFIG_LCD_ALIGNMENT
1506 Normally the LCD is page-aligned (tyically 4KB). If this is
1507 defined then the LCD will be aligned to this value instead.
1508 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1509 here, since it is cheaper to change data cache settings on
1510 a per-section basis.
1512 CONFIG_CONSOLE_SCROLL_LINES
1514 When the console need to be scrolled, this is the number of
1515 lines to scroll by. It defaults to 1. Increasing this makes
1516 the console jump but can help speed up operation when scrolling
1521 Support drawing of RLE8-compressed bitmaps on the LCD.
1525 Enables an 'i2c edid' command which can read EDID
1526 information over I2C from an attached LCD display.
1528 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1530 If this option is set, the environment is checked for
1531 a variable "splashimage". If found, the usual display
1532 of logo, copyright and system information on the LCD
1533 is suppressed and the BMP image at the address
1534 specified in "splashimage" is loaded instead. The
1535 console is redirected to the "nulldev", too. This
1536 allows for a "silent" boot where a splash screen is
1537 loaded very quickly after power-on.
1539 CONFIG_SPLASHIMAGE_GUARD
1541 If this option is set, then U-Boot will prevent the environment
1542 variable "splashimage" from being set to a problematic address
1543 (see README.displaying-bmps and README.arm-unaligned-accesses).
1544 This option is useful for targets where, due to alignment
1545 restrictions, an improperly aligned BMP image will cause a data
1546 abort. If you think you will not have problems with unaligned
1547 accesses (for example because your toolchain prevents them)
1548 there is no need to set this option.
1550 CONFIG_SPLASH_SCREEN_ALIGN
1552 If this option is set the splash image can be freely positioned
1553 on the screen. Environment variable "splashpos" specifies the
1554 position as "x,y". If a positive number is given it is used as
1555 number of pixel from left/top. If a negative number is given it
1556 is used as number of pixel from right/bottom. You can also
1557 specify 'm' for centering the image.
1560 setenv splashpos m,m
1561 => image at center of screen
1563 setenv splashpos 30,20
1564 => image at x = 30 and y = 20
1566 setenv splashpos -10,m
1567 => vertically centered image
1568 at x = dspWidth - bmpWidth - 9
1570 CONFIG_SPLASH_SCREEN_PREPARE
1572 If this option is set then the board_splash_screen_prepare()
1573 function, which must be defined in your code, is called as part
1574 of the splash screen display sequence. It gives the board an
1575 opportunity to prepare the splash image data before it is
1576 processed and sent to the frame buffer by U-Boot.
1578 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1580 If this option is set, additionally to standard BMP
1581 images, gzipped BMP images can be displayed via the
1582 splashscreen support or the bmp command.
1584 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1586 If this option is set, 8-bit RLE compressed BMP images
1587 can be displayed via the splashscreen support or the
1590 - Do compresssing for memory range:
1593 If this option is set, it would use zlib deflate method
1594 to compress the specified memory at its best effort.
1596 - Compression support:
1599 If this option is set, support for bzip2 compressed
1600 images is included. If not, only uncompressed and gzip
1601 compressed images are supported.
1603 NOTE: the bzip2 algorithm requires a lot of RAM, so
1604 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1609 If this option is set, support for lzma compressed
1612 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1613 requires an amount of dynamic memory that is given by the
1616 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1618 Where lc and lp stand for, respectively, Literal context bits
1619 and Literal pos bits.
1621 This value is upper-bounded by 14MB in the worst case. Anyway,
1622 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1623 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1624 a very small buffer.
1626 Use the lzmainfo tool to determinate the lc and lp values and
1627 then calculate the amount of needed dynamic memory (ensuring
1628 the appropriate CONFIG_SYS_MALLOC_LEN value).
1633 The address of PHY on MII bus.
1635 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1637 The clock frequency of the MII bus
1641 If this option is set, support for speed/duplex
1642 detection of gigabit PHY is included.
1644 CONFIG_PHY_RESET_DELAY
1646 Some PHY like Intel LXT971A need extra delay after
1647 reset before any MII register access is possible.
1648 For such PHY, set this option to the usec delay
1649 required. (minimum 300usec for LXT971A)
1651 CONFIG_PHY_CMD_DELAY (ppc4xx)
1653 Some PHY like Intel LXT971A need extra delay after
1654 command issued before MII status register can be read
1664 Define a default value for Ethernet address to use
1665 for the respective Ethernet interface, in case this
1666 is not determined automatically.
1671 Define a default value for the IP address to use for
1672 the default Ethernet interface, in case this is not
1673 determined through e.g. bootp.
1674 (Environment variable "ipaddr")
1676 - Server IP address:
1679 Defines a default value for the IP address of a TFTP
1680 server to contact when using the "tftboot" command.
1681 (Environment variable "serverip")
1683 CONFIG_KEEP_SERVERADDR
1685 Keeps the server's MAC address, in the env 'serveraddr'
1686 for passing to bootargs (like Linux's netconsole option)
1688 - Gateway IP address:
1691 Defines a default value for the IP address of the
1692 default router where packets to other networks are
1694 (Environment variable "gatewayip")
1699 Defines a default value for the subnet mask (or
1700 routing prefix) which is used to determine if an IP
1701 address belongs to the local subnet or needs to be
1702 forwarded through a router.
1703 (Environment variable "netmask")
1705 - Multicast TFTP Mode:
1708 Defines whether you want to support multicast TFTP as per
1709 rfc-2090; for example to work with atftp. Lets lots of targets
1710 tftp down the same boot image concurrently. Note: the Ethernet
1711 driver in use must provide a function: mcast() to join/leave a
1714 - BOOTP Recovery Mode:
1715 CONFIG_BOOTP_RANDOM_DELAY
1717 If you have many targets in a network that try to
1718 boot using BOOTP, you may want to avoid that all
1719 systems send out BOOTP requests at precisely the same
1720 moment (which would happen for instance at recovery
1721 from a power failure, when all systems will try to
1722 boot, thus flooding the BOOTP server. Defining
1723 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1724 inserted before sending out BOOTP requests. The
1725 following delays are inserted then:
1727 1st BOOTP request: delay 0 ... 1 sec
1728 2nd BOOTP request: delay 0 ... 2 sec
1729 3rd BOOTP request: delay 0 ... 4 sec
1731 BOOTP requests: delay 0 ... 8 sec
1733 - DHCP Advanced Options:
1734 You can fine tune the DHCP functionality by defining
1735 CONFIG_BOOTP_* symbols:
1737 CONFIG_BOOTP_SUBNETMASK
1738 CONFIG_BOOTP_GATEWAY
1739 CONFIG_BOOTP_HOSTNAME
1740 CONFIG_BOOTP_NISDOMAIN
1741 CONFIG_BOOTP_BOOTPATH
1742 CONFIG_BOOTP_BOOTFILESIZE
1745 CONFIG_BOOTP_SEND_HOSTNAME
1746 CONFIG_BOOTP_NTPSERVER
1747 CONFIG_BOOTP_TIMEOFFSET
1748 CONFIG_BOOTP_VENDOREX
1749 CONFIG_BOOTP_MAY_FAIL
1751 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1752 environment variable, not the BOOTP server.
1754 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1755 after the configured retry count, the call will fail
1756 instead of starting over. This can be used to fail over
1757 to Link-local IP address configuration if the DHCP server
1760 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1761 serverip from a DHCP server, it is possible that more
1762 than one DNS serverip is offered to the client.
1763 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1764 serverip will be stored in the additional environment
1765 variable "dnsip2". The first DNS serverip is always
1766 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1769 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1770 to do a dynamic update of a DNS server. To do this, they
1771 need the hostname of the DHCP requester.
1772 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1773 of the "hostname" environment variable is passed as
1774 option 12 to the DHCP server.
1776 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1778 A 32bit value in microseconds for a delay between
1779 receiving a "DHCP Offer" and sending the "DHCP Request".
1780 This fixes a problem with certain DHCP servers that don't
1781 respond 100% of the time to a "DHCP request". E.g. On an
1782 AT91RM9200 processor running at 180MHz, this delay needed
1783 to be *at least* 15,000 usec before a Windows Server 2003
1784 DHCP server would reply 100% of the time. I recommend at
1785 least 50,000 usec to be safe. The alternative is to hope
1786 that one of the retries will be successful but note that
1787 the DHCP timeout and retry process takes a longer than
1790 - Link-local IP address negotiation:
1791 Negotiate with other link-local clients on the local network
1792 for an address that doesn't require explicit configuration.
1793 This is especially useful if a DHCP server cannot be guaranteed
1794 to exist in all environments that the device must operate.
1796 See doc/README.link-local for more information.
1799 CONFIG_CDP_DEVICE_ID
1801 The device id used in CDP trigger frames.
1803 CONFIG_CDP_DEVICE_ID_PREFIX
1805 A two character string which is prefixed to the MAC address
1810 A printf format string which contains the ascii name of
1811 the port. Normally is set to "eth%d" which sets
1812 eth0 for the first Ethernet, eth1 for the second etc.
1814 CONFIG_CDP_CAPABILITIES
1816 A 32bit integer which indicates the device capabilities;
1817 0x00000010 for a normal host which does not forwards.
1821 An ascii string containing the version of the software.
1825 An ascii string containing the name of the platform.
1829 A 32bit integer sent on the trigger.
1831 CONFIG_CDP_POWER_CONSUMPTION
1833 A 16bit integer containing the power consumption of the
1834 device in .1 of milliwatts.
1836 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1838 A byte containing the id of the VLAN.
1840 - Status LED: CONFIG_STATUS_LED
1842 Several configurations allow to display the current
1843 status using a LED. For instance, the LED will blink
1844 fast while running U-Boot code, stop blinking as
1845 soon as a reply to a BOOTP request was received, and
1846 start blinking slow once the Linux kernel is running
1847 (supported by a status LED driver in the Linux
1848 kernel). Defining CONFIG_STATUS_LED enables this
1851 - CAN Support: CONFIG_CAN_DRIVER
1853 Defining CONFIG_CAN_DRIVER enables CAN driver support
1854 on those systems that support this (optional)
1855 feature, like the TQM8xxL modules.
1857 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1859 These enable I2C serial bus commands. Defining either of
1860 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1861 include the appropriate I2C driver for the selected CPU.
1863 This will allow you to use i2c commands at the u-boot
1864 command line (as long as you set CONFIG_CMD_I2C in
1865 CONFIG_COMMANDS) and communicate with i2c based realtime
1866 clock chips. See common/cmd_i2c.c for a description of the
1867 command line interface.
1869 CONFIG_HARD_I2C selects a hardware I2C controller.
1871 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1872 bit-banging) driver instead of CPM or similar hardware
1875 There are several other quantities that must also be
1876 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1878 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1879 to be the frequency (in Hz) at which you wish your i2c bus
1880 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1881 the CPU's i2c node address).
1883 Now, the u-boot i2c code for the mpc8xx
1884 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1885 and so its address should therefore be cleared to 0 (See,
1886 eg, MPC823e User's Manual p.16-473). So, set
1887 CONFIG_SYS_I2C_SLAVE to 0.
1889 CONFIG_SYS_I2C_INIT_MPC5XXX
1891 When a board is reset during an i2c bus transfer
1892 chips might think that the current transfer is still
1893 in progress. Reset the slave devices by sending start
1894 commands until the slave device responds.
1896 That's all that's required for CONFIG_HARD_I2C.
1898 If you use the software i2c interface (CONFIG_SOFT_I2C)
1899 then the following macros need to be defined (examples are
1900 from include/configs/lwmon.h):
1904 (Optional). Any commands necessary to enable the I2C
1905 controller or configure ports.
1907 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1911 (Only for MPC8260 CPU). The I/O port to use (the code
1912 assumes both bits are on the same port). Valid values
1913 are 0..3 for ports A..D.
1917 The code necessary to make the I2C data line active
1918 (driven). If the data line is open collector, this
1921 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1925 The code necessary to make the I2C data line tri-stated
1926 (inactive). If the data line is open collector, this
1929 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1933 Code that returns TRUE if the I2C data line is high,
1936 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1940 If <bit> is TRUE, sets the I2C data line high. If it
1941 is FALSE, it clears it (low).
1943 eg: #define I2C_SDA(bit) \
1944 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1945 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1949 If <bit> is TRUE, sets the I2C clock line high. If it
1950 is FALSE, it clears it (low).
1952 eg: #define I2C_SCL(bit) \
1953 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1954 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1958 This delay is invoked four times per clock cycle so this
1959 controls the rate of data transfer. The data rate thus
1960 is 1 / (I2C_DELAY * 4). Often defined to be something
1963 #define I2C_DELAY udelay(2)
1965 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1967 If your arch supports the generic GPIO framework (asm/gpio.h),
1968 then you may alternatively define the two GPIOs that are to be
1969 used as SCL / SDA. Any of the previous I2C_xxx macros will
1970 have GPIO-based defaults assigned to them as appropriate.
1972 You should define these to the GPIO value as given directly to
1973 the generic GPIO functions.
1975 CONFIG_SYS_I2C_INIT_BOARD
1977 When a board is reset during an i2c bus transfer
1978 chips might think that the current transfer is still
1979 in progress. On some boards it is possible to access
1980 the i2c SCLK line directly, either by using the
1981 processor pin as a GPIO or by having a second pin
1982 connected to the bus. If this option is defined a
1983 custom i2c_init_board() routine in boards/xxx/board.c
1984 is run early in the boot sequence.
1986 CONFIG_SYS_I2C_BOARD_LATE_INIT
1988 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1989 defined a custom i2c_board_late_init() routine in
1990 boards/xxx/board.c is run AFTER the operations in i2c_init()
1991 is completed. This callpoint can be used to unreset i2c bus
1992 using CPU i2c controller register accesses for CPUs whose i2c
1993 controller provide such a method. It is called at the end of
1994 i2c_init() to allow i2c_init operations to setup the i2c bus
1995 controller on the CPU (e.g. setting bus speed & slave address).
1997 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1999 This option enables configuration of bi_iic_fast[] flags
2000 in u-boot bd_info structure based on u-boot environment
2001 variable "i2cfast". (see also i2cfast)
2003 CONFIG_I2C_MULTI_BUS
2005 This option allows the use of multiple I2C buses, each of which
2006 must have a controller. At any point in time, only one bus is
2007 active. To switch to a different bus, use the 'i2c dev' command.
2008 Note that bus numbering is zero-based.
2010 CONFIG_SYS_I2C_NOPROBES
2012 This option specifies a list of I2C devices that will be skipped
2013 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2014 is set, specify a list of bus-device pairs. Otherwise, specify
2015 a 1D array of device addresses
2018 #undef CONFIG_I2C_MULTI_BUS
2019 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2021 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2023 #define CONFIG_I2C_MULTI_BUS
2024 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2026 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2028 CONFIG_SYS_SPD_BUS_NUM
2030 If defined, then this indicates the I2C bus number for DDR SPD.
2031 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2033 CONFIG_SYS_RTC_BUS_NUM
2035 If defined, then this indicates the I2C bus number for the RTC.
2036 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2038 CONFIG_SYS_DTT_BUS_NUM
2040 If defined, then this indicates the I2C bus number for the DTT.
2041 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2043 CONFIG_SYS_I2C_DTT_ADDR:
2045 If defined, specifies the I2C address of the DTT device.
2046 If not defined, then U-Boot uses predefined value for
2047 specified DTT device.
2051 Define this option if you want to use Freescale's I2C driver in
2052 drivers/i2c/fsl_i2c.c.
2056 Define this option if you have I2C devices reached over 1 .. n
2057 I2C Muxes like the pca9544a. This option addes a new I2C
2058 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2059 new I2C Bus to the existing I2C Busses. If you select the
2060 new Bus with "i2c dev", u-bbot sends first the commandos for
2061 the muxes to activate this new "bus".
2063 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2067 Adding a new I2C Bus reached over 2 pca9544a muxes
2068 The First mux with address 70 and channel 6
2069 The Second mux with address 71 and channel 4
2071 => i2c bus pca9544a:70:6:pca9544a:71:4
2073 Use the "i2c bus" command without parameter, to get a list
2074 of I2C Busses with muxes:
2077 Busses reached over muxes:
2079 reached over Mux(es):
2082 reached over Mux(es):
2087 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2088 u-boot first sends the command to the mux@70 to enable
2089 channel 6, and then the command to the mux@71 to enable
2092 After that, you can use the "normal" i2c commands as
2093 usual to communicate with your I2C devices behind
2096 This option is actually implemented for the bitbanging
2097 algorithm in common/soft_i2c.c and for the Hardware I2C
2098 Bus on the MPC8260. But it should be not so difficult
2099 to add this option to other architectures.
2101 CONFIG_SOFT_I2C_READ_REPEATED_START
2103 defining this will force the i2c_read() function in
2104 the soft_i2c driver to perform an I2C repeated start
2105 between writing the address pointer and reading the
2106 data. If this define is omitted the default behaviour
2107 of doing a stop-start sequence will be used. Most I2C
2108 devices can use either method, but some require one or
2111 - SPI Support: CONFIG_SPI
2113 Enables SPI driver (so far only tested with
2114 SPI EEPROM, also an instance works with Crystal A/D and
2115 D/As on the SACSng board)
2119 Enables the driver for SPI controller on SuperH. Currently
2120 only SH7757 is supported.
2124 Enables extended (16-bit) SPI EEPROM addressing.
2125 (symmetrical to CONFIG_I2C_X)
2129 Enables a software (bit-bang) SPI driver rather than
2130 using hardware support. This is a general purpose
2131 driver that only requires three general I/O port pins
2132 (two outputs, one input) to function. If this is
2133 defined, the board configuration must define several
2134 SPI configuration items (port pins to use, etc). For
2135 an example, see include/configs/sacsng.h.
2139 Enables a hardware SPI driver for general-purpose reads
2140 and writes. As with CONFIG_SOFT_SPI, the board configuration
2141 must define a list of chip-select function pointers.
2142 Currently supported on some MPC8xxx processors. For an
2143 example, see include/configs/mpc8349emds.h.
2147 Enables the driver for the SPI controllers on i.MX and MXC
2148 SoCs. Currently i.MX31/35/51 are supported.
2150 - FPGA Support: CONFIG_FPGA
2152 Enables FPGA subsystem.
2154 CONFIG_FPGA_<vendor>
2156 Enables support for specific chip vendors.
2159 CONFIG_FPGA_<family>
2161 Enables support for FPGA family.
2162 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2166 Specify the number of FPGA devices to support.
2168 CONFIG_SYS_FPGA_PROG_FEEDBACK
2170 Enable printing of hash marks during FPGA configuration.
2172 CONFIG_SYS_FPGA_CHECK_BUSY
2174 Enable checks on FPGA configuration interface busy
2175 status by the configuration function. This option
2176 will require a board or device specific function to
2181 If defined, a function that provides delays in the FPGA
2182 configuration driver.
2184 CONFIG_SYS_FPGA_CHECK_CTRLC
2185 Allow Control-C to interrupt FPGA configuration
2187 CONFIG_SYS_FPGA_CHECK_ERROR
2189 Check for configuration errors during FPGA bitfile
2190 loading. For example, abort during Virtex II
2191 configuration if the INIT_B line goes low (which
2192 indicated a CRC error).
2194 CONFIG_SYS_FPGA_WAIT_INIT
2196 Maximum time to wait for the INIT_B line to deassert
2197 after PROB_B has been deasserted during a Virtex II
2198 FPGA configuration sequence. The default time is 500
2201 CONFIG_SYS_FPGA_WAIT_BUSY
2203 Maximum time to wait for BUSY to deassert during
2204 Virtex II FPGA configuration. The default is 5 ms.
2206 CONFIG_SYS_FPGA_WAIT_CONFIG
2208 Time to wait after FPGA configuration. The default is
2211 - Configuration Management:
2214 If defined, this string will be added to the U-Boot
2215 version information (U_BOOT_VERSION)
2217 - Vendor Parameter Protection:
2219 U-Boot considers the values of the environment
2220 variables "serial#" (Board Serial Number) and
2221 "ethaddr" (Ethernet Address) to be parameters that
2222 are set once by the board vendor / manufacturer, and
2223 protects these variables from casual modification by
2224 the user. Once set, these variables are read-only,
2225 and write or delete attempts are rejected. You can
2226 change this behaviour:
2228 If CONFIG_ENV_OVERWRITE is #defined in your config
2229 file, the write protection for vendor parameters is
2230 completely disabled. Anybody can change or delete
2233 Alternatively, if you #define _both_ CONFIG_ETHADDR
2234 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2235 Ethernet address is installed in the environment,
2236 which can be changed exactly ONCE by the user. [The
2237 serial# is unaffected by this, i. e. it remains
2240 The same can be accomplished in a more flexible way
2241 for any variable by configuring the type of access
2242 to allow for those variables in the ".flags" variable
2243 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2248 Define this variable to enable the reservation of
2249 "protected RAM", i. e. RAM which is not overwritten
2250 by U-Boot. Define CONFIG_PRAM to hold the number of
2251 kB you want to reserve for pRAM. You can overwrite
2252 this default value by defining an environment
2253 variable "pram" to the number of kB you want to
2254 reserve. Note that the board info structure will
2255 still show the full amount of RAM. If pRAM is
2256 reserved, a new environment variable "mem" will
2257 automatically be defined to hold the amount of
2258 remaining RAM in a form that can be passed as boot
2259 argument to Linux, for instance like that:
2261 setenv bootargs ... mem=\${mem}
2264 This way you can tell Linux not to use this memory,
2265 either, which results in a memory region that will
2266 not be affected by reboots.
2268 *WARNING* If your board configuration uses automatic
2269 detection of the RAM size, you must make sure that
2270 this memory test is non-destructive. So far, the
2271 following board configurations are known to be
2274 IVMS8, IVML24, SPD8xx, TQM8xxL,
2275 HERMES, IP860, RPXlite, LWMON,
2278 - Access to physical memory region (> 4GB)
2279 Some basic support is provided for operations on memory not
2280 normally accessible to U-Boot - e.g. some architectures
2281 support access to more than 4GB of memory on 32-bit
2282 machines using physical address extension or similar.
2283 Define CONFIG_PHYSMEM to access this basic support, which
2284 currently only supports clearing the memory.
2289 Define this variable to stop the system in case of a
2290 fatal error, so that you have to reset it manually.
2291 This is probably NOT a good idea for an embedded
2292 system where you want the system to reboot
2293 automatically as fast as possible, but it may be
2294 useful during development since you can try to debug
2295 the conditions that lead to the situation.
2297 CONFIG_NET_RETRY_COUNT
2299 This variable defines the number of retries for
2300 network operations like ARP, RARP, TFTP, or BOOTP
2301 before giving up the operation. If not defined, a
2302 default value of 5 is used.
2306 Timeout waiting for an ARP reply in milliseconds.
2310 Timeout in milliseconds used in NFS protocol.
2311 If you encounter "ERROR: Cannot umount" in nfs command,
2312 try longer timeout such as
2313 #define CONFIG_NFS_TIMEOUT 10000UL
2315 - Command Interpreter:
2316 CONFIG_AUTO_COMPLETE
2318 Enable auto completion of commands using TAB.
2320 Note that this feature has NOT been implemented yet
2321 for the "hush" shell.
2324 CONFIG_SYS_HUSH_PARSER
2326 Define this variable to enable the "hush" shell (from
2327 Busybox) as command line interpreter, thus enabling
2328 powerful command line syntax like
2329 if...then...else...fi conditionals or `&&' and '||'
2330 constructs ("shell scripts").
2332 If undefined, you get the old, much simpler behaviour
2333 with a somewhat smaller memory footprint.
2336 CONFIG_SYS_PROMPT_HUSH_PS2
2338 This defines the secondary prompt string, which is
2339 printed when the command interpreter needs more input
2340 to complete a command. Usually "> ".
2344 In the current implementation, the local variables
2345 space and global environment variables space are
2346 separated. Local variables are those you define by
2347 simply typing `name=value'. To access a local
2348 variable later on, you have write `$name' or
2349 `${name}'; to execute the contents of a variable
2350 directly type `$name' at the command prompt.
2352 Global environment variables are those you use
2353 setenv/printenv to work with. To run a command stored
2354 in such a variable, you need to use the run command,
2355 and you must not use the '$' sign to access them.
2357 To store commands and special characters in a
2358 variable, please use double quotation marks
2359 surrounding the whole text of the variable, instead
2360 of the backslashes before semicolons and special
2363 - Commandline Editing and History:
2364 CONFIG_CMDLINE_EDITING
2366 Enable editing and History functions for interactive
2367 commandline input operations
2369 - Default Environment:
2370 CONFIG_EXTRA_ENV_SETTINGS
2372 Define this to contain any number of null terminated
2373 strings (variable = value pairs) that will be part of
2374 the default environment compiled into the boot image.
2376 For example, place something like this in your
2377 board's config file:
2379 #define CONFIG_EXTRA_ENV_SETTINGS \
2383 Warning: This method is based on knowledge about the
2384 internal format how the environment is stored by the
2385 U-Boot code. This is NOT an official, exported
2386 interface! Although it is unlikely that this format
2387 will change soon, there is no guarantee either.
2388 You better know what you are doing here.
2390 Note: overly (ab)use of the default environment is
2391 discouraged. Make sure to check other ways to preset
2392 the environment like the "source" command or the
2395 CONFIG_ENV_VARS_UBOOT_CONFIG
2397 Define this in order to add variables describing the
2398 U-Boot build configuration to the default environment.
2399 These will be named arch, cpu, board, vendor, and soc.
2401 Enabling this option will cause the following to be defined:
2409 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2411 Define this in order to add variables describing certain
2412 run-time determined information about the hardware to the
2413 environment. These will be named board_name, board_rev.
2415 CONFIG_DELAY_ENVIRONMENT
2417 Normally the environment is loaded when the board is
2418 intialised so that it is available to U-Boot. This inhibits
2419 that so that the environment is not available until
2420 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2421 this is instead controlled by the value of
2422 /config/load-environment.
2424 - DataFlash Support:
2425 CONFIG_HAS_DATAFLASH
2427 Defining this option enables DataFlash features and
2428 allows to read/write in Dataflash via the standard
2431 - Serial Flash support
2434 Defining this option enables SPI flash commands
2435 'sf probe/read/write/erase/update'.
2437 Usage requires an initial 'probe' to define the serial
2438 flash parameters, followed by read/write/erase/update
2441 The following defaults may be provided by the platform
2442 to handle the common case when only a single serial
2443 flash is present on the system.
2445 CONFIG_SF_DEFAULT_BUS Bus identifier
2446 CONFIG_SF_DEFAULT_CS Chip-select
2447 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2448 CONFIG_SF_DEFAULT_SPEED in Hz
2452 Define this option to include a destructive SPI flash
2455 - SystemACE Support:
2458 Adding this option adds support for Xilinx SystemACE
2459 chips attached via some sort of local bus. The address
2460 of the chip must also be defined in the
2461 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2463 #define CONFIG_SYSTEMACE
2464 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2466 When SystemACE support is added, the "ace" device type
2467 becomes available to the fat commands, i.e. fatls.
2469 - TFTP Fixed UDP Port:
2472 If this is defined, the environment variable tftpsrcp
2473 is used to supply the TFTP UDP source port value.
2474 If tftpsrcp isn't defined, the normal pseudo-random port
2475 number generator is used.
2477 Also, the environment variable tftpdstp is used to supply
2478 the TFTP UDP destination port value. If tftpdstp isn't
2479 defined, the normal port 69 is used.
2481 The purpose for tftpsrcp is to allow a TFTP server to
2482 blindly start the TFTP transfer using the pre-configured
2483 target IP address and UDP port. This has the effect of
2484 "punching through" the (Windows XP) firewall, allowing
2485 the remainder of the TFTP transfer to proceed normally.
2486 A better solution is to properly configure the firewall,
2487 but sometimes that is not allowed.
2492 This enables a generic 'hash' command which can produce
2493 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2497 Enable the hash verify command (hash -v). This adds to code
2500 CONFIG_SHA1 - support SHA1 hashing
2501 CONFIG_SHA256 - support SHA256 hashing
2503 Note: There is also a sha1sum command, which should perhaps
2504 be deprecated in favour of 'hash sha1'.
2506 - Show boot progress:
2507 CONFIG_SHOW_BOOT_PROGRESS
2509 Defining this option allows to add some board-
2510 specific code (calling a user-provided function
2511 "show_boot_progress(int)") that enables you to show
2512 the system's boot progress on some display (for
2513 example, some LED's) on your board. At the moment,
2514 the following checkpoints are implemented:
2516 - Detailed boot stage timing
2518 Define this option to get detailed timing of each stage
2519 of the boot process.
2521 CONFIG_BOOTSTAGE_USER_COUNT
2522 This is the number of available user bootstage records.
2523 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2524 a new ID will be allocated from this stash. If you exceed
2525 the limit, recording will stop.
2527 CONFIG_BOOTSTAGE_REPORT
2528 Define this to print a report before boot, similar to this:
2530 Timer summary in microseconds:
2533 3,575,678 3,575,678 board_init_f start
2534 3,575,695 17 arch_cpu_init A9
2535 3,575,777 82 arch_cpu_init done
2536 3,659,598 83,821 board_init_r start
2537 3,910,375 250,777 main_loop
2538 29,916,167 26,005,792 bootm_start
2539 30,361,327 445,160 start_kernel
2541 CONFIG_CMD_BOOTSTAGE
2542 Add a 'bootstage' command which supports printing a report
2543 and un/stashing of bootstage data.
2545 CONFIG_BOOTSTAGE_FDT
2546 Stash the bootstage information in the FDT. A root 'bootstage'
2547 node is created with each bootstage id as a child. Each child
2548 has a 'name' property and either 'mark' containing the
2549 mark time in microsecond, or 'accum' containing the
2550 accumulated time for that bootstage id in microseconds.
2555 name = "board_init_f";
2564 Code in the Linux kernel can find this in /proc/devicetree.
2566 Legacy uImage format:
2569 1 common/cmd_bootm.c before attempting to boot an image
2570 -1 common/cmd_bootm.c Image header has bad magic number
2571 2 common/cmd_bootm.c Image header has correct magic number
2572 -2 common/cmd_bootm.c Image header has bad checksum
2573 3 common/cmd_bootm.c Image header has correct checksum
2574 -3 common/cmd_bootm.c Image data has bad checksum
2575 4 common/cmd_bootm.c Image data has correct checksum
2576 -4 common/cmd_bootm.c Image is for unsupported architecture
2577 5 common/cmd_bootm.c Architecture check OK
2578 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2579 6 common/cmd_bootm.c Image Type check OK
2580 -6 common/cmd_bootm.c gunzip uncompression error
2581 -7 common/cmd_bootm.c Unimplemented compression type
2582 7 common/cmd_bootm.c Uncompression OK
2583 8 common/cmd_bootm.c No uncompress/copy overwrite error
2584 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2586 9 common/image.c Start initial ramdisk verification
2587 -10 common/image.c Ramdisk header has bad magic number
2588 -11 common/image.c Ramdisk header has bad checksum
2589 10 common/image.c Ramdisk header is OK
2590 -12 common/image.c Ramdisk data has bad checksum
2591 11 common/image.c Ramdisk data has correct checksum
2592 12 common/image.c Ramdisk verification complete, start loading
2593 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2594 13 common/image.c Start multifile image verification
2595 14 common/image.c No initial ramdisk, no multifile, continue.
2597 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2599 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2600 -31 post/post.c POST test failed, detected by post_output_backlog()
2601 -32 post/post.c POST test failed, detected by post_run_single()
2603 34 common/cmd_doc.c before loading a Image from a DOC device
2604 -35 common/cmd_doc.c Bad usage of "doc" command
2605 35 common/cmd_doc.c correct usage of "doc" command
2606 -36 common/cmd_doc.c No boot device
2607 36 common/cmd_doc.c correct boot device
2608 -37 common/cmd_doc.c Unknown Chip ID on boot device
2609 37 common/cmd_doc.c correct chip ID found, device available
2610 -38 common/cmd_doc.c Read Error on boot device
2611 38 common/cmd_doc.c reading Image header from DOC device OK
2612 -39 common/cmd_doc.c Image header has bad magic number
2613 39 common/cmd_doc.c Image header has correct magic number
2614 -40 common/cmd_doc.c Error reading Image from DOC device
2615 40 common/cmd_doc.c Image header has correct magic number
2616 41 common/cmd_ide.c before loading a Image from a IDE device
2617 -42 common/cmd_ide.c Bad usage of "ide" command
2618 42 common/cmd_ide.c correct usage of "ide" command
2619 -43 common/cmd_ide.c No boot device
2620 43 common/cmd_ide.c boot device found
2621 -44 common/cmd_ide.c Device not available
2622 44 common/cmd_ide.c Device available
2623 -45 common/cmd_ide.c wrong partition selected
2624 45 common/cmd_ide.c partition selected
2625 -46 common/cmd_ide.c Unknown partition table
2626 46 common/cmd_ide.c valid partition table found
2627 -47 common/cmd_ide.c Invalid partition type
2628 47 common/cmd_ide.c correct partition type
2629 -48 common/cmd_ide.c Error reading Image Header on boot device
2630 48 common/cmd_ide.c reading Image Header from IDE device OK
2631 -49 common/cmd_ide.c Image header has bad magic number
2632 49 common/cmd_ide.c Image header has correct magic number
2633 -50 common/cmd_ide.c Image header has bad checksum
2634 50 common/cmd_ide.c Image header has correct checksum
2635 -51 common/cmd_ide.c Error reading Image from IDE device
2636 51 common/cmd_ide.c reading Image from IDE device OK
2637 52 common/cmd_nand.c before loading a Image from a NAND device
2638 -53 common/cmd_nand.c Bad usage of "nand" command
2639 53 common/cmd_nand.c correct usage of "nand" command
2640 -54 common/cmd_nand.c No boot device
2641 54 common/cmd_nand.c boot device found
2642 -55 common/cmd_nand.c Unknown Chip ID on boot device
2643 55 common/cmd_nand.c correct chip ID found, device available
2644 -56 common/cmd_nand.c Error reading Image Header on boot device
2645 56 common/cmd_nand.c reading Image Header from NAND device OK
2646 -57 common/cmd_nand.c Image header has bad magic number
2647 57 common/cmd_nand.c Image header has correct magic number
2648 -58 common/cmd_nand.c Error reading Image from NAND device
2649 58 common/cmd_nand.c reading Image from NAND device OK
2651 -60 common/env_common.c Environment has a bad CRC, using default
2653 64 net/eth.c starting with Ethernet configuration.
2654 -64 net/eth.c no Ethernet found.
2655 65 net/eth.c Ethernet found.
2657 -80 common/cmd_net.c usage wrong
2658 80 common/cmd_net.c before calling NetLoop()
2659 -81 common/cmd_net.c some error in NetLoop() occurred
2660 81 common/cmd_net.c NetLoop() back without error
2661 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2662 82 common/cmd_net.c trying automatic boot
2663 83 common/cmd_net.c running "source" command
2664 -83 common/cmd_net.c some error in automatic boot or "source" command
2665 84 common/cmd_net.c end without errors
2670 100 common/cmd_bootm.c Kernel FIT Image has correct format
2671 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2672 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2673 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2674 102 common/cmd_bootm.c Kernel unit name specified
2675 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2676 103 common/cmd_bootm.c Found configuration node
2677 104 common/cmd_bootm.c Got kernel subimage node offset
2678 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2679 105 common/cmd_bootm.c Kernel subimage hash verification OK
2680 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2681 106 common/cmd_bootm.c Architecture check OK
2682 -106 common/cmd_bootm.c Kernel subimage has wrong type
2683 107 common/cmd_bootm.c Kernel subimage type OK
2684 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2685 108 common/cmd_bootm.c Got kernel subimage data/size
2686 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2687 -109 common/cmd_bootm.c Can't get kernel subimage type
2688 -110 common/cmd_bootm.c Can't get kernel subimage comp
2689 -111 common/cmd_bootm.c Can't get kernel subimage os
2690 -112 common/cmd_bootm.c Can't get kernel subimage load address
2691 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2693 120 common/image.c Start initial ramdisk verification
2694 -120 common/image.c Ramdisk FIT image has incorrect format
2695 121 common/image.c Ramdisk FIT image has correct format
2696 122 common/image.c No ramdisk subimage unit name, using configuration
2697 -122 common/image.c Can't get configuration for ramdisk subimage
2698 123 common/image.c Ramdisk unit name specified
2699 -124 common/image.c Can't get ramdisk subimage node offset
2700 125 common/image.c Got ramdisk subimage node offset
2701 -125 common/image.c Ramdisk subimage hash verification failed
2702 126 common/image.c Ramdisk subimage hash verification OK
2703 -126 common/image.c Ramdisk subimage for unsupported architecture
2704 127 common/image.c Architecture check OK
2705 -127 common/image.c Can't get ramdisk subimage data/size
2706 128 common/image.c Got ramdisk subimage data/size
2707 129 common/image.c Can't get ramdisk load address
2708 -129 common/image.c Got ramdisk load address
2710 -130 common/cmd_doc.c Incorrect FIT image format
2711 131 common/cmd_doc.c FIT image format OK
2713 -140 common/cmd_ide.c Incorrect FIT image format
2714 141 common/cmd_ide.c FIT image format OK
2716 -150 common/cmd_nand.c Incorrect FIT image format
2717 151 common/cmd_nand.c FIT image format OK
2719 - FIT image support:
2721 Enable support for the FIT uImage format.
2723 CONFIG_FIT_BEST_MATCH
2724 When no configuration is explicitly selected, default to the
2725 one whose fdt's compatibility field best matches that of
2726 U-Boot itself. A match is considered "best" if it matches the
2727 most specific compatibility entry of U-Boot's fdt's root node.
2728 The order of entries in the configuration's fdt is ignored.
2730 - Standalone program support:
2731 CONFIG_STANDALONE_LOAD_ADDR
2733 This option defines a board specific value for the
2734 address where standalone program gets loaded, thus
2735 overwriting the architecture dependent default
2738 - Frame Buffer Address:
2741 Define CONFIG_FB_ADDR if you want to use specific
2742 address for frame buffer. This is typically the case
2743 when using a graphics controller has separate video
2744 memory. U-Boot will then place the frame buffer at
2745 the given address instead of dynamically reserving it
2746 in system RAM by calling lcd_setmem(), which grabs
2747 the memory for the frame buffer depending on the
2748 configured panel size.
2750 Please see board_init_f function.
2752 - Automatic software updates via TFTP server
2754 CONFIG_UPDATE_TFTP_CNT_MAX
2755 CONFIG_UPDATE_TFTP_MSEC_MAX
2757 These options enable and control the auto-update feature;
2758 for a more detailed description refer to doc/README.update.
2760 - MTD Support (mtdparts command, UBI support)
2763 Adds the MTD device infrastructure from the Linux kernel.
2764 Needed for mtdparts command support.
2766 CONFIG_MTD_PARTITIONS
2768 Adds the MTD partitioning infrastructure from the Linux
2769 kernel. Needed for UBI support.
2773 Enable building of SPL globally.
2776 LDSCRIPT for linking the SPL binary.
2779 Maximum binary size (text, data and rodata) of the SPL binary.
2781 CONFIG_SPL_TEXT_BASE
2782 TEXT_BASE for linking the SPL binary.
2784 CONFIG_SPL_RELOC_TEXT_BASE
2785 Address to relocate to. If unspecified, this is equal to
2786 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2788 CONFIG_SPL_BSS_START_ADDR
2789 Link address for the BSS within the SPL binary.
2791 CONFIG_SPL_BSS_MAX_SIZE
2792 Maximum binary size of the BSS section of the SPL binary.
2795 Adress of the start of the stack SPL will use
2797 CONFIG_SPL_RELOC_STACK
2798 Adress of the start of the stack SPL will use after
2799 relocation. If unspecified, this is equal to
2802 CONFIG_SYS_SPL_MALLOC_START
2803 Starting address of the malloc pool used in SPL.
2805 CONFIG_SYS_SPL_MALLOC_SIZE
2806 The size of the malloc pool used in SPL.
2808 CONFIG_SPL_FRAMEWORK
2809 Enable the SPL framework under common/. This framework
2810 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2811 NAND loading of the Linux Kernel.
2813 CONFIG_SPL_DISPLAY_PRINT
2814 For ARM, enable an optional function to print more information
2815 about the running system.
2817 CONFIG_SPL_INIT_MINIMAL
2818 Arch init code should be built for a very small image
2820 CONFIG_SPL_LIBCOMMON_SUPPORT
2821 Support for common/libcommon.o in SPL binary
2823 CONFIG_SPL_LIBDISK_SUPPORT
2824 Support for disk/libdisk.o in SPL binary
2826 CONFIG_SPL_I2C_SUPPORT
2827 Support for drivers/i2c/libi2c.o in SPL binary
2829 CONFIG_SPL_GPIO_SUPPORT
2830 Support for drivers/gpio/libgpio.o in SPL binary
2832 CONFIG_SPL_MMC_SUPPORT
2833 Support for drivers/mmc/libmmc.o in SPL binary
2835 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2836 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2837 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2838 Address, size and partition on the MMC to load U-Boot from
2839 when the MMC is being used in raw mode.
2841 CONFIG_SPL_FAT_SUPPORT
2842 Support for fs/fat/libfat.o in SPL binary
2844 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2845 Filename to read to load U-Boot when reading from FAT
2847 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2848 Set this for NAND SPL on PPC mpc83xx targets, so that
2849 start.S waits for the rest of the SPL to load before
2850 continuing (the hardware starts execution after just
2851 loading the first page rather than the full 4K).
2853 CONFIG_SPL_NAND_BASE
2854 Include nand_base.c in the SPL. Requires
2855 CONFIG_SPL_NAND_DRIVERS.
2857 CONFIG_SPL_NAND_DRIVERS
2858 SPL uses normal NAND drivers, not minimal drivers.
2861 Include standard software ECC in the SPL
2863 CONFIG_SPL_NAND_SIMPLE
2864 Support for NAND boot using simple NAND drivers that
2865 expose the cmd_ctrl() interface.
2867 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2868 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2869 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2870 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2871 CONFIG_SYS_NAND_ECCBYTES
2872 Defines the size and behavior of the NAND that SPL uses
2875 CONFIG_SYS_NAND_U_BOOT_OFFS
2876 Location in NAND to read U-Boot from
2878 CONFIG_SYS_NAND_U_BOOT_DST
2879 Location in memory to load U-Boot to
2881 CONFIG_SYS_NAND_U_BOOT_SIZE
2882 Size of image to load
2884 CONFIG_SYS_NAND_U_BOOT_START
2885 Entry point in loaded image to jump to
2887 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2888 Define this if you need to first read the OOB and then the
2889 data. This is used for example on davinci plattforms.
2891 CONFIG_SPL_OMAP3_ID_NAND
2892 Support for an OMAP3-specific set of functions to return the
2893 ID and MFR of the first attached NAND chip, if present.
2895 CONFIG_SPL_SERIAL_SUPPORT
2896 Support for drivers/serial/libserial.o in SPL binary
2898 CONFIG_SPL_SPI_FLASH_SUPPORT
2899 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2901 CONFIG_SPL_SPI_SUPPORT
2902 Support for drivers/spi/libspi.o in SPL binary
2904 CONFIG_SPL_RAM_DEVICE
2905 Support for running image already present in ram, in SPL binary
2907 CONFIG_SPL_LIBGENERIC_SUPPORT
2908 Support for lib/libgeneric.o in SPL binary
2911 Linker address to which the SPL should be padded before
2912 appending the SPL payload.
2915 Final target image containing SPL and payload. Some SPLs
2916 use an arch-specific makefile fragment instead, for
2917 example if more than one image needs to be produced.
2922 [so far only for SMDK2400 boards]
2924 - Modem support enable:
2925 CONFIG_MODEM_SUPPORT
2927 - RTS/CTS Flow control enable:
2930 - Modem debug support:
2931 CONFIG_MODEM_SUPPORT_DEBUG
2933 Enables debugging stuff (char screen[1024], dbg())
2934 for modem support. Useful only with BDI2000.
2936 - Interrupt support (PPC):
2938 There are common interrupt_init() and timer_interrupt()
2939 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2940 for CPU specific initialization. interrupt_init_cpu()
2941 should set decrementer_count to appropriate value. If
2942 CPU resets decrementer automatically after interrupt
2943 (ppc4xx) it should set decrementer_count to zero.
2944 timer_interrupt() calls timer_interrupt_cpu() for CPU
2945 specific handling. If board has watchdog / status_led
2946 / other_activity_monitor it works automatically from
2947 general timer_interrupt().
2951 In the target system modem support is enabled when a
2952 specific key (key combination) is pressed during
2953 power-on. Otherwise U-Boot will boot normally
2954 (autoboot). The key_pressed() function is called from
2955 board_init(). Currently key_pressed() is a dummy
2956 function, returning 1 and thus enabling modem
2959 If there are no modem init strings in the
2960 environment, U-Boot proceed to autoboot; the
2961 previous output (banner, info printfs) will be
2964 See also: doc/README.Modem
2966 Board initialization settings:
2967 ------------------------------
2969 During Initialization u-boot calls a number of board specific functions
2970 to allow the preparation of board specific prerequisites, e.g. pin setup
2971 before drivers are initialized. To enable these callbacks the
2972 following configuration macros have to be defined. Currently this is
2973 architecture specific, so please check arch/your_architecture/lib/board.c
2974 typically in board_init_f() and board_init_r().
2976 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2977 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2978 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2979 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2981 Configuration Settings:
2982 -----------------------
2984 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2985 undefine this when you're short of memory.
2987 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2988 width of the commands listed in the 'help' command output.
2990 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2991 prompt for user input.
2993 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2995 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2997 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2999 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3000 the application (usually a Linux kernel) when it is
3003 - CONFIG_SYS_BAUDRATE_TABLE:
3004 List of legal baudrate settings for this board.
3006 - CONFIG_SYS_CONSOLE_INFO_QUIET
3007 Suppress display of console information at boot.
3009 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3010 If the board specific function
3011 extern int overwrite_console (void);
3012 returns 1, the stdin, stderr and stdout are switched to the
3013 serial port, else the settings in the environment are used.
3015 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3016 Enable the call to overwrite_console().
3018 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3019 Enable overwrite of previous console environment settings.
3021 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3022 Begin and End addresses of the area used by the
3025 - CONFIG_SYS_ALT_MEMTEST:
3026 Enable an alternate, more extensive memory test.
3028 - CONFIG_SYS_MEMTEST_SCRATCH:
3029 Scratch address used by the alternate memory test
3030 You only need to set this if address zero isn't writeable
3032 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3033 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3034 this specified memory area will get subtracted from the top
3035 (end) of RAM and won't get "touched" at all by U-Boot. By
3036 fixing up gd->ram_size the Linux kernel should gets passed
3037 the now "corrected" memory size and won't touch it either.
3038 This should work for arch/ppc and arch/powerpc. Only Linux
3039 board ports in arch/powerpc with bootwrapper support that
3040 recalculate the memory size from the SDRAM controller setup
3041 will have to get fixed in Linux additionally.
3043 This option can be used as a workaround for the 440EPx/GRx
3044 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3047 WARNING: Please make sure that this value is a multiple of
3048 the Linux page size (normally 4k). If this is not the case,
3049 then the end address of the Linux memory will be located at a
3050 non page size aligned address and this could cause major
3053 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3054 Enable temporary baudrate change while serial download
3056 - CONFIG_SYS_SDRAM_BASE:
3057 Physical start address of SDRAM. _Must_ be 0 here.
3059 - CONFIG_SYS_MBIO_BASE:
3060 Physical start address of Motherboard I/O (if using a
3063 - CONFIG_SYS_FLASH_BASE:
3064 Physical start address of Flash memory.
3066 - CONFIG_SYS_MONITOR_BASE:
3067 Physical start address of boot monitor code (set by
3068 make config files to be same as the text base address
3069 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3070 CONFIG_SYS_FLASH_BASE when booting from flash.
3072 - CONFIG_SYS_MONITOR_LEN:
3073 Size of memory reserved for monitor code, used to
3074 determine _at_compile_time_ (!) if the environment is
3075 embedded within the U-Boot image, or in a separate
3078 - CONFIG_SYS_MALLOC_LEN:
3079 Size of DRAM reserved for malloc() use.
3081 - CONFIG_SYS_BOOTM_LEN:
3082 Normally compressed uImages are limited to an
3083 uncompressed size of 8 MBytes. If this is not enough,
3084 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3085 to adjust this setting to your needs.
3087 - CONFIG_SYS_BOOTMAPSZ:
3088 Maximum size of memory mapped by the startup code of
3089 the Linux kernel; all data that must be processed by
3090 the Linux kernel (bd_info, boot arguments, FDT blob if
3091 used) must be put below this limit, unless "bootm_low"
3092 enviroment variable is defined and non-zero. In such case
3093 all data for the Linux kernel must be between "bootm_low"
3094 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3095 variable "bootm_mapsize" will override the value of
3096 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3097 then the value in "bootm_size" will be used instead.
3099 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3100 Enable initrd_high functionality. If defined then the
3101 initrd_high feature is enabled and the bootm ramdisk subcommand
3104 - CONFIG_SYS_BOOT_GET_CMDLINE:
3105 Enables allocating and saving kernel cmdline in space between
3106 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3108 - CONFIG_SYS_BOOT_GET_KBD:
3109 Enables allocating and saving a kernel copy of the bd_info in
3110 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3112 - CONFIG_SYS_MAX_FLASH_BANKS:
3113 Max number of Flash memory banks
3115 - CONFIG_SYS_MAX_FLASH_SECT:
3116 Max number of sectors on a Flash chip
3118 - CONFIG_SYS_FLASH_ERASE_TOUT:
3119 Timeout for Flash erase operations (in ms)
3121 - CONFIG_SYS_FLASH_WRITE_TOUT:
3122 Timeout for Flash write operations (in ms)
3124 - CONFIG_SYS_FLASH_LOCK_TOUT
3125 Timeout for Flash set sector lock bit operation (in ms)
3127 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3128 Timeout for Flash clear lock bits operation (in ms)
3130 - CONFIG_SYS_FLASH_PROTECTION
3131 If defined, hardware flash sectors protection is used
3132 instead of U-Boot software protection.
3134 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3136 Enable TFTP transfers directly to flash memory;
3137 without this option such a download has to be
3138 performed in two steps: (1) download to RAM, and (2)
3139 copy from RAM to flash.
3141 The two-step approach is usually more reliable, since
3142 you can check if the download worked before you erase
3143 the flash, but in some situations (when system RAM is
3144 too limited to allow for a temporary copy of the
3145 downloaded image) this option may be very useful.
3147 - CONFIG_SYS_FLASH_CFI:
3148 Define if the flash driver uses extra elements in the
3149 common flash structure for storing flash geometry.
3151 - CONFIG_FLASH_CFI_DRIVER
3152 This option also enables the building of the cfi_flash driver
3153 in the drivers directory
3155 - CONFIG_FLASH_CFI_MTD
3156 This option enables the building of the cfi_mtd driver
3157 in the drivers directory. The driver exports CFI flash
3160 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3161 Use buffered writes to flash.
3163 - CONFIG_FLASH_SPANSION_S29WS_N
3164 s29ws-n MirrorBit flash has non-standard addresses for buffered
3167 - CONFIG_SYS_FLASH_QUIET_TEST
3168 If this option is defined, the common CFI flash doesn't
3169 print it's warning upon not recognized FLASH banks. This
3170 is useful, if some of the configured banks are only
3171 optionally available.
3173 - CONFIG_FLASH_SHOW_PROGRESS
3174 If defined (must be an integer), print out countdown
3175 digits and dots. Recommended value: 45 (9..1) for 80
3176 column displays, 15 (3..1) for 40 column displays.
3178 - CONFIG_SYS_RX_ETH_BUFFER:
3179 Defines the number of Ethernet receive buffers. On some
3180 Ethernet controllers it is recommended to set this value
3181 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3182 buffers can be full shortly after enabling the interface
3183 on high Ethernet traffic.
3184 Defaults to 4 if not defined.
3186 - CONFIG_ENV_MAX_ENTRIES
3188 Maximum number of entries in the hash table that is used
3189 internally to store the environment settings. The default
3190 setting is supposed to be generous and should work in most
3191 cases. This setting can be used to tune behaviour; see
3192 lib/hashtable.c for details.
3194 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3195 - CONFIG_ENV_FLAGS_LIST_STATIC
3196 Enable validation of the values given to enviroment variables when
3197 calling env set. Variables can be restricted to only decimal,
3198 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3199 the variables can also be restricted to IP address or MAC address.
3201 The format of the list is:
3202 type_attribute = [s|d|x|b|i|m]
3203 access_atribute = [a|r|o|c]
3204 attributes = type_attribute[access_atribute]
3205 entry = variable_name[:attributes]
3208 The type attributes are:
3209 s - String (default)
3212 b - Boolean ([1yYtT|0nNfF])
3216 The access attributes are:
3222 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3223 Define this to a list (string) to define the ".flags"
3224 envirnoment variable in the default or embedded environment.
3226 - CONFIG_ENV_FLAGS_LIST_STATIC
3227 Define this to a list (string) to define validation that
3228 should be done if an entry is not found in the ".flags"
3229 environment variable. To override a setting in the static
3230 list, simply add an entry for the same variable name to the
3233 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3234 If defined, don't allow the -f switch to env set override variable
3237 - CONFIG_SYS_GENERIC_BOARD
3238 This selects the architecture-generic board system instead of the
3239 architecture-specific board files. It is intended to move boards
3240 to this new framework over time. Defining this will disable the
3241 arch/foo/lib/board.c file and use common/board_f.c and
3242 common/board_r.c instead. To use this option your architecture
3243 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3244 its config.mk file). If you find problems enabling this option on
3245 your board please report the problem and send patches!
3247 - CONFIG_SYS_SYM_OFFSETS
3248 This is set by architectures that use offsets for link symbols
3249 instead of absolute values. So bss_start is obtained using an
3250 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3251 directly. You should not need to touch this setting.
3254 The following definitions that deal with the placement and management
3255 of environment data (variable area); in general, we support the
3256 following configurations:
3258 - CONFIG_BUILD_ENVCRC:
3260 Builds up envcrc with the target environment so that external utils
3261 may easily extract it and embed it in final U-Boot images.
3263 - CONFIG_ENV_IS_IN_FLASH:
3265 Define this if the environment is in flash memory.
3267 a) The environment occupies one whole flash sector, which is
3268 "embedded" in the text segment with the U-Boot code. This
3269 happens usually with "bottom boot sector" or "top boot
3270 sector" type flash chips, which have several smaller
3271 sectors at the start or the end. For instance, such a
3272 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3273 such a case you would place the environment in one of the
3274 4 kB sectors - with U-Boot code before and after it. With
3275 "top boot sector" type flash chips, you would put the
3276 environment in one of the last sectors, leaving a gap
3277 between U-Boot and the environment.
3279 - CONFIG_ENV_OFFSET:
3281 Offset of environment data (variable area) to the
3282 beginning of flash memory; for instance, with bottom boot
3283 type flash chips the second sector can be used: the offset
3284 for this sector is given here.
3286 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3290 This is just another way to specify the start address of
3291 the flash sector containing the environment (instead of
3294 - CONFIG_ENV_SECT_SIZE:
3296 Size of the sector containing the environment.
3299 b) Sometimes flash chips have few, equal sized, BIG sectors.
3300 In such a case you don't want to spend a whole sector for
3305 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3306 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3307 of this flash sector for the environment. This saves
3308 memory for the RAM copy of the environment.
3310 It may also save flash memory if you decide to use this
3311 when your environment is "embedded" within U-Boot code,
3312 since then the remainder of the flash sector could be used
3313 for U-Boot code. It should be pointed out that this is
3314 STRONGLY DISCOURAGED from a robustness point of view:
3315 updating the environment in flash makes it always
3316 necessary to erase the WHOLE sector. If something goes
3317 wrong before the contents has been restored from a copy in
3318 RAM, your target system will be dead.
3320 - CONFIG_ENV_ADDR_REDUND
3321 CONFIG_ENV_SIZE_REDUND
3323 These settings describe a second storage area used to hold
3324 a redundant copy of the environment data, so that there is
3325 a valid backup copy in case there is a power failure during
3326 a "saveenv" operation.
3328 BE CAREFUL! Any changes to the flash layout, and some changes to the
3329 source code will make it necessary to adapt <board>/u-boot.lds*
3333 - CONFIG_ENV_IS_IN_NVRAM:
3335 Define this if you have some non-volatile memory device
3336 (NVRAM, battery buffered SRAM) which you want to use for the
3342 These two #defines are used to determine the memory area you
3343 want to use for environment. It is assumed that this memory
3344 can just be read and written to, without any special
3347 BE CAREFUL! The first access to the environment happens quite early
3348 in U-Boot initalization (when we try to get the setting of for the
3349 console baudrate). You *MUST* have mapped your NVRAM area then, or
3352 Please note that even with NVRAM we still use a copy of the
3353 environment in RAM: we could work on NVRAM directly, but we want to
3354 keep settings there always unmodified except somebody uses "saveenv"
3355 to save the current settings.
3358 - CONFIG_ENV_IS_IN_EEPROM:
3360 Use this if you have an EEPROM or similar serial access
3361 device and a driver for it.
3363 - CONFIG_ENV_OFFSET:
3366 These two #defines specify the offset and size of the
3367 environment area within the total memory of your EEPROM.
3369 - CONFIG_SYS_I2C_EEPROM_ADDR:
3370 If defined, specified the chip address of the EEPROM device.
3371 The default address is zero.
3373 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3374 If defined, the number of bits used to address bytes in a
3375 single page in the EEPROM device. A 64 byte page, for example
3376 would require six bits.
3378 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3379 If defined, the number of milliseconds to delay between
3380 page writes. The default is zero milliseconds.
3382 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3383 The length in bytes of the EEPROM memory array address. Note
3384 that this is NOT the chip address length!
3386 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3387 EEPROM chips that implement "address overflow" are ones
3388 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3389 address and the extra bits end up in the "chip address" bit
3390 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3393 Note that we consider the length of the address field to
3394 still be one byte because the extra address bits are hidden
3395 in the chip address.
3397 - CONFIG_SYS_EEPROM_SIZE:
3398 The size in bytes of the EEPROM device.
3400 - CONFIG_ENV_EEPROM_IS_ON_I2C
3401 define this, if you have I2C and SPI activated, and your
3402 EEPROM, which holds the environment, is on the I2C bus.
3404 - CONFIG_I2C_ENV_EEPROM_BUS
3405 if you have an Environment on an EEPROM reached over
3406 I2C muxes, you can define here, how to reach this
3407 EEPROM. For example:
3409 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3411 EEPROM which holds the environment, is reached over
3412 a pca9547 i2c mux with address 0x70, channel 3.
3414 - CONFIG_ENV_IS_IN_DATAFLASH:
3416 Define this if you have a DataFlash memory device which you
3417 want to use for the environment.
3419 - CONFIG_ENV_OFFSET:
3423 These three #defines specify the offset and size of the
3424 environment area within the total memory of your DataFlash placed
3425 at the specified address.
3427 - CONFIG_ENV_IS_IN_REMOTE:
3429 Define this if you have a remote memory space which you
3430 want to use for the local device's environment.
3435 These two #defines specify the address and size of the
3436 environment area within the remote memory space. The
3437 local device can get the environment from remote memory
3438 space by SRIO or PCIE links.
3440 BE CAREFUL! For some special cases, the local device can not use
3441 "saveenv" command. For example, the local device will get the
3442 environment stored in a remote NOR flash by SRIO or PCIE link,
3443 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3445 - CONFIG_ENV_IS_IN_NAND:
3447 Define this if you have a NAND device which you want to use
3448 for the environment.
3450 - CONFIG_ENV_OFFSET:
3453 These two #defines specify the offset and size of the environment
3454 area within the first NAND device. CONFIG_ENV_OFFSET must be
3455 aligned to an erase block boundary.
3457 - CONFIG_ENV_OFFSET_REDUND (optional):
3459 This setting describes a second storage area of CONFIG_ENV_SIZE
3460 size used to hold a redundant copy of the environment data, so
3461 that there is a valid backup copy in case there is a power failure
3462 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3463 aligned to an erase block boundary.
3465 - CONFIG_ENV_RANGE (optional):
3467 Specifies the length of the region in which the environment
3468 can be written. This should be a multiple of the NAND device's
3469 block size. Specifying a range with more erase blocks than
3470 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3471 the range to be avoided.
3473 - CONFIG_ENV_OFFSET_OOB (optional):
3475 Enables support for dynamically retrieving the offset of the
3476 environment from block zero's out-of-band data. The
3477 "nand env.oob" command can be used to record this offset.
3478 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3479 using CONFIG_ENV_OFFSET_OOB.
3481 - CONFIG_NAND_ENV_DST
3483 Defines address in RAM to which the nand_spl code should copy the
3484 environment. If redundant environment is used, it will be copied to
3485 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3487 - CONFIG_SYS_SPI_INIT_OFFSET
3489 Defines offset to the initial SPI buffer area in DPRAM. The
3490 area is used at an early stage (ROM part) if the environment
3491 is configured to reside in the SPI EEPROM: We need a 520 byte
3492 scratch DPRAM area. It is used between the two initialization
3493 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3494 to be a good choice since it makes it far enough from the
3495 start of the data area as well as from the stack pointer.
3497 Please note that the environment is read-only until the monitor
3498 has been relocated to RAM and a RAM copy of the environment has been
3499 created; also, when using EEPROM you will have to use getenv_f()
3500 until then to read environment variables.
3502 The environment is protected by a CRC32 checksum. Before the monitor
3503 is relocated into RAM, as a result of a bad CRC you will be working
3504 with the compiled-in default environment - *silently*!!! [This is
3505 necessary, because the first environment variable we need is the
3506 "baudrate" setting for the console - if we have a bad CRC, we don't
3507 have any device yet where we could complain.]
3509 Note: once the monitor has been relocated, then it will complain if
3510 the default environment is used; a new CRC is computed as soon as you
3511 use the "saveenv" command to store a valid environment.
3513 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3514 Echo the inverted Ethernet link state to the fault LED.
3516 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3517 also needs to be defined.
3519 - CONFIG_SYS_FAULT_MII_ADDR:
3520 MII address of the PHY to check for the Ethernet link state.
3522 - CONFIG_NS16550_MIN_FUNCTIONS:
3523 Define this if you desire to only have use of the NS16550_init
3524 and NS16550_putc functions for the serial driver located at
3525 drivers/serial/ns16550.c. This option is useful for saving
3526 space for already greatly restricted images, including but not
3527 limited to NAND_SPL configurations.
3529 - CONFIG_DISPLAY_BOARDINFO
3530 Display information about the board that U-Boot is running on
3531 when U-Boot starts up. The board function checkboard() is called
3534 - CONFIG_DISPLAY_BOARDINFO_LATE
3535 Similar to the previous option, but display this information
3536 later, once stdio is running and output goes to the LCD, if
3539 Low Level (hardware related) configuration options:
3540 ---------------------------------------------------
3542 - CONFIG_SYS_CACHELINE_SIZE:
3543 Cache Line Size of the CPU.
3545 - CONFIG_SYS_DEFAULT_IMMR:
3546 Default address of the IMMR after system reset.
3548 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3549 and RPXsuper) to be able to adjust the position of
3550 the IMMR register after a reset.
3552 - CONFIG_SYS_CCSRBAR_DEFAULT:
3553 Default (power-on reset) physical address of CCSR on Freescale
3556 - CONFIG_SYS_CCSRBAR:
3557 Virtual address of CCSR. On a 32-bit build, this is typically
3558 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3560 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3561 for cross-platform code that uses that macro instead.
3563 - CONFIG_SYS_CCSRBAR_PHYS:
3564 Physical address of CCSR. CCSR can be relocated to a new
3565 physical address, if desired. In this case, this macro should
3566 be set to that address. Otherwise, it should be set to the
3567 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3568 is typically relocated on 36-bit builds. It is recommended
3569 that this macro be defined via the _HIGH and _LOW macros:
3571 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3572 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3574 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3575 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3576 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3577 used in assembly code, so it must not contain typecasts or
3578 integer size suffixes (e.g. "ULL").
3580 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3581 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3582 used in assembly code, so it must not contain typecasts or
3583 integer size suffixes (e.g. "ULL").
3585 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3586 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3587 forced to a value that ensures that CCSR is not relocated.
3589 - Floppy Disk Support:
3590 CONFIG_SYS_FDC_DRIVE_NUMBER
3592 the default drive number (default value 0)
3594 CONFIG_SYS_ISA_IO_STRIDE
3596 defines the spacing between FDC chipset registers
3599 CONFIG_SYS_ISA_IO_OFFSET
3601 defines the offset of register from address. It
3602 depends on which part of the data bus is connected to
3603 the FDC chipset. (default value 0)
3605 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3606 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3609 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3610 fdc_hw_init() is called at the beginning of the FDC
3611 setup. fdc_hw_init() must be provided by the board
3612 source code. It is used to make hardware dependant
3616 Most IDE controllers were designed to be connected with PCI
3617 interface. Only few of them were designed for AHB interface.
3618 When software is doing ATA command and data transfer to
3619 IDE devices through IDE-AHB controller, some additional
3620 registers accessing to these kind of IDE-AHB controller
3623 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3624 DO NOT CHANGE unless you know exactly what you're
3625 doing! (11-4) [MPC8xx/82xx systems only]
3627 - CONFIG_SYS_INIT_RAM_ADDR:
3629 Start address of memory area that can be used for
3630 initial data and stack; please note that this must be
3631 writable memory that is working WITHOUT special
3632 initialization, i. e. you CANNOT use normal RAM which
3633 will become available only after programming the
3634 memory controller and running certain initialization
3637 U-Boot uses the following memory types:
3638 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3639 - MPC824X: data cache
3640 - PPC4xx: data cache
3642 - CONFIG_SYS_GBL_DATA_OFFSET:
3644 Offset of the initial data structure in the memory
3645 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3646 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3647 data is located at the end of the available space
3648 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3649 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3650 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3651 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3654 On the MPC824X (or other systems that use the data
3655 cache for initial memory) the address chosen for
3656 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3657 point to an otherwise UNUSED address space between
3658 the top of RAM and the start of the PCI space.
3660 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3662 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3664 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3666 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3668 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3670 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3672 - CONFIG_SYS_OR_TIMING_SDRAM:
3675 - CONFIG_SYS_MAMR_PTA:
3676 periodic timer for refresh
3678 - CONFIG_SYS_DER: Debug Event Register (37-47)
3680 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3681 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3682 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3683 CONFIG_SYS_BR1_PRELIM:
3684 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3686 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3687 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3688 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3689 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3691 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3692 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3693 Machine Mode Register and Memory Periodic Timer
3694 Prescaler definitions (SDRAM timing)
3696 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3697 enable I2C microcode relocation patch (MPC8xx);
3698 define relocation offset in DPRAM [DSP2]
3700 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3701 enable SMC microcode relocation patch (MPC8xx);
3702 define relocation offset in DPRAM [SMC1]
3704 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3705 enable SPI microcode relocation patch (MPC8xx);
3706 define relocation offset in DPRAM [SCC4]
3708 - CONFIG_SYS_USE_OSCCLK:
3709 Use OSCM clock mode on MBX8xx board. Be careful,
3710 wrong setting might damage your board. Read
3711 doc/README.MBX before setting this variable!
3713 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3714 Offset of the bootmode word in DPRAM used by post
3715 (Power On Self Tests). This definition overrides
3716 #define'd default value in commproc.h resp.
3719 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3720 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3721 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3722 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3723 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3724 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3725 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3726 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3727 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3729 - CONFIG_PCI_DISABLE_PCIE:
3730 Disable PCI-Express on systems where it is supported but not
3733 - CONFIG_PCI_ENUM_ONLY
3734 Only scan through and get the devices on the busses.
3735 Don't do any setup work, presumably because someone or
3736 something has already done it, and we don't need to do it
3737 a second time. Useful for platforms that are pre-booted
3738 by coreboot or similar.
3741 Chip has SRIO or not
3744 Board has SRIO 1 port available
3747 Board has SRIO 2 port available
3749 - CONFIG_SYS_SRIOn_MEM_VIRT:
3750 Virtual Address of SRIO port 'n' memory region
3752 - CONFIG_SYS_SRIOn_MEM_PHYS:
3753 Physical Address of SRIO port 'n' memory region
3755 - CONFIG_SYS_SRIOn_MEM_SIZE:
3756 Size of SRIO port 'n' memory region
3758 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3759 Defined to tell the NAND controller that the NAND chip is using
3761 Not all NAND drivers use this symbol.
3762 Example of driver that uses it:
3763 - drivers/mtd/nand/ndfc.c
3765 - CONFIG_SYS_NDFC_EBC0_CFG
3766 Sets the EBC0_CFG register for the NDFC. If not defined
3767 a default value will be used.
3770 Get DDR timing information from an I2C EEPROM. Common
3771 with pluggable memory modules such as SODIMMs
3774 I2C address of the SPD EEPROM
3776 - CONFIG_SYS_SPD_BUS_NUM
3777 If SPD EEPROM is on an I2C bus other than the first
3778 one, specify here. Note that the value must resolve
3779 to something your driver can deal with.
3781 - CONFIG_SYS_DDR_RAW_TIMING
3782 Get DDR timing information from other than SPD. Common with
3783 soldered DDR chips onboard without SPD. DDR raw timing
3784 parameters are extracted from datasheet and hard-coded into
3785 header files or board specific files.
3787 - CONFIG_FSL_DDR_INTERACTIVE
3788 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3790 - CONFIG_SYS_83XX_DDR_USES_CS0
3791 Only for 83xx systems. If specified, then DDR should
3792 be configured using CS0 and CS1 instead of CS2 and CS3.
3794 - CONFIG_ETHER_ON_FEC[12]
3795 Define to enable FEC[12] on a 8xx series processor.
3797 - CONFIG_FEC[12]_PHY
3798 Define to the hardcoded PHY address which corresponds
3799 to the given FEC; i. e.
3800 #define CONFIG_FEC1_PHY 4
3801 means that the PHY with address 4 is connected to FEC1
3803 When set to -1, means to probe for first available.
3805 - CONFIG_FEC[12]_PHY_NORXERR
3806 The PHY does not have a RXERR line (RMII only).
3807 (so program the FEC to ignore it).
3810 Enable RMII mode for all FECs.
3811 Note that this is a global option, we can't
3812 have one FEC in standard MII mode and another in RMII mode.
3814 - CONFIG_CRC32_VERIFY
3815 Add a verify option to the crc32 command.
3818 => crc32 -v <address> <count> <crc32>
3820 Where address/count indicate a memory area
3821 and crc32 is the correct crc32 which the
3825 Add the "loopw" memory command. This only takes effect if
3826 the memory commands are activated globally (CONFIG_CMD_MEM).
3829 Add the "mdc" and "mwc" memory commands. These are cyclic
3834 This command will print 4 bytes (10,11,12,13) each 500 ms.
3836 => mwc.l 100 12345678 10
3837 This command will write 12345678 to address 100 all 10 ms.
3839 This only takes effect if the memory commands are activated
3840 globally (CONFIG_CMD_MEM).
3842 - CONFIG_SKIP_LOWLEVEL_INIT
3843 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3844 low level initializations (like setting up the memory
3845 controller) are omitted and/or U-Boot does not
3846 relocate itself into RAM.
3848 Normally this variable MUST NOT be defined. The only
3849 exception is when U-Boot is loaded (to RAM) by some
3850 other boot loader or by a debugger which performs
3851 these initializations itself.
3854 Modifies the behaviour of start.S when compiling a loader
3855 that is executed before the actual U-Boot. E.g. when
3856 compiling a NAND SPL.
3858 - CONFIG_ARCH_MAP_SYSMEM
3859 Generally U-Boot (and in particular the md command) uses
3860 effective address. It is therefore not necessary to regard
3861 U-Boot address as virtual addresses that need to be translated
3862 to physical addresses. However, sandbox requires this, since
3863 it maintains its own little RAM buffer which contains all
3864 addressable memory. This option causes some memory accesses
3865 to be mapped through map_sysmem() / unmap_sysmem().
3867 - CONFIG_USE_ARCH_MEMCPY
3868 CONFIG_USE_ARCH_MEMSET
3869 If these options are used a optimized version of memcpy/memset will
3870 be used if available. These functions may be faster under some
3871 conditions but may increase the binary size.
3873 - CONFIG_X86_RESET_VECTOR
3874 If defined, the x86 reset vector code is included. This is not
3875 needed when U-Boot is running from Coreboot.
3878 Defines the MPU clock speed (in MHz).
3880 NOTE : currently only supported on AM335x platforms.
3882 Freescale QE/FMAN Firmware Support:
3883 -----------------------------------
3885 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3886 loading of "firmware", which is encoded in the QE firmware binary format.
3887 This firmware often needs to be loaded during U-Boot booting, so macros
3888 are used to identify the storage device (NOR flash, SPI, etc) and the address
3891 - CONFIG_SYS_QE_FMAN_FW_ADDR
3892 The address in the storage device where the firmware is located. The
3893 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3896 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3897 The maximum possible size of the firmware. The firmware binary format
3898 has a field that specifies the actual size of the firmware, but it
3899 might not be possible to read any part of the firmware unless some
3900 local storage is allocated to hold the entire firmware first.
3902 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3903 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3904 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3905 virtual address in NOR flash.
3907 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3908 Specifies that QE/FMAN firmware is located in NAND flash.
3909 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3911 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3912 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3913 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3915 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3916 Specifies that QE/FMAN firmware is located on the primary SPI
3917 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3919 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3920 Specifies that QE/FMAN firmware is located in the remote (master)
3921 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3922 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3923 window->master inbound window->master LAW->the ucode address in
3924 master's memory space.
3926 Building the Software:
3927 ======================
3929 Building U-Boot has been tested in several native build environments
3930 and in many different cross environments. Of course we cannot support
3931 all possibly existing versions of cross development tools in all
3932 (potentially obsolete) versions. In case of tool chain problems we
3933 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3934 which is extensively used to build and test U-Boot.
3936 If you are not using a native environment, it is assumed that you
3937 have GNU cross compiling tools available in your path. In this case,
3938 you must set the environment variable CROSS_COMPILE in your shell.
3939 Note that no changes to the Makefile or any other source files are
3940 necessary. For example using the ELDK on a 4xx CPU, please enter:
3942 $ CROSS_COMPILE=ppc_4xx-
3943 $ export CROSS_COMPILE
3945 Note: If you wish to generate Windows versions of the utilities in
3946 the tools directory you can use the MinGW toolchain
3947 (http://www.mingw.org). Set your HOST tools to the MinGW
3948 toolchain and execute 'make tools'. For example:
3950 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3952 Binaries such as tools/mkimage.exe will be created which can
3953 be executed on computers running Windows.
3955 U-Boot is intended to be simple to build. After installing the
3956 sources you must configure U-Boot for one specific board type. This
3961 where "NAME_config" is the name of one of the existing configu-
3962 rations; see boards.cfg for supported names.
3964 Note: for some board special configuration names may exist; check if
3965 additional information is available from the board vendor; for
3966 instance, the TQM823L systems are available without (standard)
3967 or with LCD support. You can select such additional "features"
3968 when choosing the configuration, i. e.
3971 - will configure for a plain TQM823L, i. e. no LCD support
3973 make TQM823L_LCD_config
3974 - will configure for a TQM823L with U-Boot console on LCD
3979 Finally, type "make all", and you should get some working U-Boot
3980 images ready for download to / installation on your system:
3982 - "u-boot.bin" is a raw binary image
3983 - "u-boot" is an image in ELF binary format
3984 - "u-boot.srec" is in Motorola S-Record format
3986 By default the build is performed locally and the objects are saved
3987 in the source directory. One of the two methods can be used to change
3988 this behavior and build U-Boot to some external directory:
3990 1. Add O= to the make command line invocations:
3992 make O=/tmp/build distclean
3993 make O=/tmp/build NAME_config
3994 make O=/tmp/build all
3996 2. Set environment variable BUILD_DIR to point to the desired location:
3998 export BUILD_DIR=/tmp/build
4003 Note that the command line "O=" setting overrides the BUILD_DIR environment
4007 Please be aware that the Makefiles assume you are using GNU make, so
4008 for instance on NetBSD you might need to use "gmake" instead of
4012 If the system board that you have is not listed, then you will need
4013 to port U-Boot to your hardware platform. To do this, follow these
4016 1. Add a new configuration option for your board to the toplevel
4017 "boards.cfg" file, using the existing entries as examples.
4018 Follow the instructions there to keep the boards in order.
4019 2. Create a new directory to hold your board specific code. Add any
4020 files you need. In your board directory, you will need at least
4021 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4022 3. Create a new configuration file "include/configs/<board>.h" for
4024 3. If you're porting U-Boot to a new CPU, then also create a new
4025 directory to hold your CPU specific code. Add any files you need.
4026 4. Run "make <board>_config" with your new name.
4027 5. Type "make", and you should get a working "u-boot.srec" file
4028 to be installed on your target system.
4029 6. Debug and solve any problems that might arise.
4030 [Of course, this last step is much harder than it sounds.]
4033 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4034 ==============================================================
4036 If you have modified U-Boot sources (for instance added a new board
4037 or support for new devices, a new CPU, etc.) you are expected to
4038 provide feedback to the other developers. The feedback normally takes
4039 the form of a "patch", i. e. a context diff against a certain (latest
4040 official or latest in the git repository) version of U-Boot sources.
4042 But before you submit such a patch, please verify that your modifi-
4043 cation did not break existing code. At least make sure that *ALL* of
4044 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4045 just run the "MAKEALL" script, which will configure and build U-Boot
4046 for ALL supported system. Be warned, this will take a while. You can
4047 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4048 environment variable to the script, i. e. to use the ELDK cross tools
4051 CROSS_COMPILE=ppc_8xx- MAKEALL
4053 or to build on a native PowerPC system you can type
4055 CROSS_COMPILE=' ' MAKEALL
4057 When using the MAKEALL script, the default behaviour is to build
4058 U-Boot in the source directory. This location can be changed by
4059 setting the BUILD_DIR environment variable. Also, for each target
4060 built, the MAKEALL script saves two log files (<target>.ERR and
4061 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4062 location can be changed by setting the MAKEALL_LOGDIR environment
4063 variable. For example:
4065 export BUILD_DIR=/tmp/build
4066 export MAKEALL_LOGDIR=/tmp/log
4067 CROSS_COMPILE=ppc_8xx- MAKEALL
4069 With the above settings build objects are saved in the /tmp/build,
4070 log files are saved in the /tmp/log and the source tree remains clean
4071 during the whole build process.
4074 See also "U-Boot Porting Guide" below.
4077 Monitor Commands - Overview:
4078 ============================
4080 go - start application at address 'addr'
4081 run - run commands in an environment variable
4082 bootm - boot application image from memory
4083 bootp - boot image via network using BootP/TFTP protocol
4084 bootz - boot zImage from memory
4085 tftpboot- boot image via network using TFTP protocol
4086 and env variables "ipaddr" and "serverip"
4087 (and eventually "gatewayip")
4088 tftpput - upload a file via network using TFTP protocol
4089 rarpboot- boot image via network using RARP/TFTP protocol
4090 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4091 loads - load S-Record file over serial line
4092 loadb - load binary file over serial line (kermit mode)
4094 mm - memory modify (auto-incrementing)
4095 nm - memory modify (constant address)
4096 mw - memory write (fill)
4098 cmp - memory compare
4099 crc32 - checksum calculation
4100 i2c - I2C sub-system
4101 sspi - SPI utility commands
4102 base - print or set address offset
4103 printenv- print environment variables
4104 setenv - set environment variables
4105 saveenv - save environment variables to persistent storage
4106 protect - enable or disable FLASH write protection
4107 erase - erase FLASH memory
4108 flinfo - print FLASH memory information
4109 nand - NAND memory operations (see doc/README.nand)
4110 bdinfo - print Board Info structure
4111 iminfo - print header information for application image
4112 coninfo - print console devices and informations
4113 ide - IDE sub-system
4114 loop - infinite loop on address range
4115 loopw - infinite write loop on address range
4116 mtest - simple RAM test
4117 icache - enable or disable instruction cache
4118 dcache - enable or disable data cache
4119 reset - Perform RESET of the CPU
4120 echo - echo args to console
4121 version - print monitor version
4122 help - print online help
4123 ? - alias for 'help'
4126 Monitor Commands - Detailed Description:
4127 ========================================
4131 For now: just type "help <command>".
4134 Environment Variables:
4135 ======================
4137 U-Boot supports user configuration using Environment Variables which
4138 can be made persistent by saving to Flash memory.
4140 Environment Variables are set using "setenv", printed using
4141 "printenv", and saved to Flash using "saveenv". Using "setenv"
4142 without a value can be used to delete a variable from the
4143 environment. As long as you don't save the environment you are
4144 working with an in-memory copy. In case the Flash area containing the
4145 environment is erased by accident, a default environment is provided.
4147 Some configuration options can be set using Environment Variables.
4149 List of environment variables (most likely not complete):
4151 baudrate - see CONFIG_BAUDRATE
4153 bootdelay - see CONFIG_BOOTDELAY
4155 bootcmd - see CONFIG_BOOTCOMMAND
4157 bootargs - Boot arguments when booting an RTOS image
4159 bootfile - Name of the image to load with TFTP
4161 bootm_low - Memory range available for image processing in the bootm
4162 command can be restricted. This variable is given as
4163 a hexadecimal number and defines lowest address allowed
4164 for use by the bootm command. See also "bootm_size"
4165 environment variable. Address defined by "bootm_low" is
4166 also the base of the initial memory mapping for the Linux
4167 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4170 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4171 This variable is given as a hexadecimal number and it
4172 defines the size of the memory region starting at base
4173 address bootm_low that is accessible by the Linux kernel
4174 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4175 as the default value if it is defined, and bootm_size is
4178 bootm_size - Memory range available for image processing in the bootm
4179 command can be restricted. This variable is given as
4180 a hexadecimal number and defines the size of the region
4181 allowed for use by the bootm command. See also "bootm_low"
4182 environment variable.
4184 updatefile - Location of the software update file on a TFTP server, used
4185 by the automatic software update feature. Please refer to
4186 documentation in doc/README.update for more details.
4188 autoload - if set to "no" (any string beginning with 'n'),
4189 "bootp" will just load perform a lookup of the
4190 configuration from the BOOTP server, but not try to
4191 load any image using TFTP
4193 autostart - if set to "yes", an image loaded using the "bootp",
4194 "rarpboot", "tftpboot" or "diskboot" commands will
4195 be automatically started (by internally calling
4198 If set to "no", a standalone image passed to the
4199 "bootm" command will be copied to the load address
4200 (and eventually uncompressed), but NOT be started.
4201 This can be used to load and uncompress arbitrary
4204 fdt_high - if set this restricts the maximum address that the
4205 flattened device tree will be copied into upon boot.
4206 For example, if you have a system with 1 GB memory
4207 at physical address 0x10000000, while Linux kernel
4208 only recognizes the first 704 MB as low memory, you
4209 may need to set fdt_high as 0x3C000000 to have the
4210 device tree blob be copied to the maximum address
4211 of the 704 MB low memory, so that Linux kernel can
4212 access it during the boot procedure.
4214 If this is set to the special value 0xFFFFFFFF then
4215 the fdt will not be copied at all on boot. For this
4216 to work it must reside in writable memory, have
4217 sufficient padding on the end of it for u-boot to
4218 add the information it needs into it, and the memory
4219 must be accessible by the kernel.
4221 fdtcontroladdr- if set this is the address of the control flattened
4222 device tree used by U-Boot when CONFIG_OF_CONTROL is
4225 i2cfast - (PPC405GP|PPC405EP only)
4226 if set to 'y' configures Linux I2C driver for fast
4227 mode (400kHZ). This environment variable is used in
4228 initialization code. So, for changes to be effective
4229 it must be saved and board must be reset.
4231 initrd_high - restrict positioning of initrd images:
4232 If this variable is not set, initrd images will be
4233 copied to the highest possible address in RAM; this
4234 is usually what you want since it allows for
4235 maximum initrd size. If for some reason you want to
4236 make sure that the initrd image is loaded below the
4237 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4238 variable to a value of "no" or "off" or "0".
4239 Alternatively, you can set it to a maximum upper
4240 address to use (U-Boot will still check that it
4241 does not overwrite the U-Boot stack and data).
4243 For instance, when you have a system with 16 MB
4244 RAM, and want to reserve 4 MB from use by Linux,
4245 you can do this by adding "mem=12M" to the value of
4246 the "bootargs" variable. However, now you must make
4247 sure that the initrd image is placed in the first
4248 12 MB as well - this can be done with
4250 setenv initrd_high 00c00000
4252 If you set initrd_high to 0xFFFFFFFF, this is an
4253 indication to U-Boot that all addresses are legal
4254 for the Linux kernel, including addresses in flash
4255 memory. In this case U-Boot will NOT COPY the
4256 ramdisk at all. This may be useful to reduce the
4257 boot time on your system, but requires that this
4258 feature is supported by your Linux kernel.
4260 ipaddr - IP address; needed for tftpboot command
4262 loadaddr - Default load address for commands like "bootp",
4263 "rarpboot", "tftpboot", "loadb" or "diskboot"
4265 loads_echo - see CONFIG_LOADS_ECHO
4267 serverip - TFTP server IP address; needed for tftpboot command
4269 bootretry - see CONFIG_BOOT_RETRY_TIME
4271 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4273 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4275 ethprime - controls which interface is used first.
4277 ethact - controls which interface is currently active.
4278 For example you can do the following
4280 => setenv ethact FEC
4281 => ping 192.168.0.1 # traffic sent on FEC
4282 => setenv ethact SCC
4283 => ping 10.0.0.1 # traffic sent on SCC
4285 ethrotate - When set to "no" U-Boot does not go through all
4286 available network interfaces.
4287 It just stays at the currently selected interface.
4289 netretry - When set to "no" each network operation will
4290 either succeed or fail without retrying.
4291 When set to "once" the network operation will
4292 fail when all the available network interfaces
4293 are tried once without success.
4294 Useful on scripts which control the retry operation
4297 npe_ucode - set load address for the NPE microcode
4299 tftpsrcport - If this is set, the value is used for TFTP's
4302 tftpdstport - If this is set, the value is used for TFTP's UDP
4303 destination port instead of the Well Know Port 69.
4305 tftpblocksize - Block size to use for TFTP transfers; if not set,
4306 we use the TFTP server's default block size
4308 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4309 seconds, minimum value is 1000 = 1 second). Defines
4310 when a packet is considered to be lost so it has to
4311 be retransmitted. The default is 5000 = 5 seconds.
4312 Lowering this value may make downloads succeed
4313 faster in networks with high packet loss rates or
4314 with unreliable TFTP servers.
4316 vlan - When set to a value < 4095 the traffic over
4317 Ethernet is encapsulated/received over 802.1q
4320 The following image location variables contain the location of images
4321 used in booting. The "Image" column gives the role of the image and is
4322 not an environment variable name. The other columns are environment
4323 variable names. "File Name" gives the name of the file on a TFTP
4324 server, "RAM Address" gives the location in RAM the image will be
4325 loaded to, and "Flash Location" gives the image's address in NOR
4326 flash or offset in NAND flash.
4328 *Note* - these variables don't have to be defined for all boards, some
4329 boards currenlty use other variables for these purposes, and some
4330 boards use these variables for other purposes.
4332 Image File Name RAM Address Flash Location
4333 ----- --------- ----------- --------------
4334 u-boot u-boot u-boot_addr_r u-boot_addr
4335 Linux kernel bootfile kernel_addr_r kernel_addr
4336 device tree blob fdtfile fdt_addr_r fdt_addr
4337 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4339 The following environment variables may be used and automatically
4340 updated by the network boot commands ("bootp" and "rarpboot"),
4341 depending the information provided by your boot server:
4343 bootfile - see above
4344 dnsip - IP address of your Domain Name Server
4345 dnsip2 - IP address of your secondary Domain Name Server
4346 gatewayip - IP address of the Gateway (Router) to use
4347 hostname - Target hostname
4349 netmask - Subnet Mask
4350 rootpath - Pathname of the root filesystem on the NFS server
4351 serverip - see above
4354 There are two special Environment Variables:
4356 serial# - contains hardware identification information such
4357 as type string and/or serial number
4358 ethaddr - Ethernet address
4360 These variables can be set only once (usually during manufacturing of
4361 the board). U-Boot refuses to delete or overwrite these variables
4362 once they have been set once.
4365 Further special Environment Variables:
4367 ver - Contains the U-Boot version string as printed
4368 with the "version" command. This variable is
4369 readonly (see CONFIG_VERSION_VARIABLE).
4372 Please note that changes to some configuration parameters may take
4373 only effect after the next boot (yes, that's just like Windoze :-).
4376 Callback functions for environment variables:
4377 ---------------------------------------------
4379 For some environment variables, the behavior of u-boot needs to change
4380 when their values are changed. This functionailty allows functions to
4381 be associated with arbitrary variables. On creation, overwrite, or
4382 deletion, the callback will provide the opportunity for some side
4383 effect to happen or for the change to be rejected.
4385 The callbacks are named and associated with a function using the
4386 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4388 These callbacks are associated with variables in one of two ways. The
4389 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4390 in the board configuration to a string that defines a list of
4391 associations. The list must be in the following format:
4393 entry = variable_name[:callback_name]
4396 If the callback name is not specified, then the callback is deleted.
4397 Spaces are also allowed anywhere in the list.
4399 Callbacks can also be associated by defining the ".callbacks" variable
4400 with the same list format above. Any association in ".callbacks" will
4401 override any association in the static list. You can define
4402 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4403 ".callbacks" envirnoment variable in the default or embedded environment.
4406 Command Line Parsing:
4407 =====================
4409 There are two different command line parsers available with U-Boot:
4410 the old "simple" one, and the much more powerful "hush" shell:
4412 Old, simple command line parser:
4413 --------------------------------
4415 - supports environment variables (through setenv / saveenv commands)
4416 - several commands on one line, separated by ';'
4417 - variable substitution using "... ${name} ..." syntax
4418 - special characters ('$', ';') can be escaped by prefixing with '\',
4420 setenv bootcmd bootm \${address}
4421 - You can also escape text by enclosing in single apostrophes, for example:
4422 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4427 - similar to Bourne shell, with control structures like
4428 if...then...else...fi, for...do...done; while...do...done,
4429 until...do...done, ...
4430 - supports environment ("global") variables (through setenv / saveenv
4431 commands) and local shell variables (through standard shell syntax
4432 "name=value"); only environment variables can be used with "run"
4438 (1) If a command line (or an environment variable executed by a "run"
4439 command) contains several commands separated by semicolon, and
4440 one of these commands fails, then the remaining commands will be
4443 (2) If you execute several variables with one call to run (i. e.
4444 calling run with a list of variables as arguments), any failing
4445 command will cause "run" to terminate, i. e. the remaining
4446 variables are not executed.
4448 Note for Redundant Ethernet Interfaces:
4449 =======================================
4451 Some boards come with redundant Ethernet interfaces; U-Boot supports
4452 such configurations and is capable of automatic selection of a
4453 "working" interface when needed. MAC assignment works as follows:
4455 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4456 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4457 "eth1addr" (=>eth1), "eth2addr", ...
4459 If the network interface stores some valid MAC address (for instance
4460 in SROM), this is used as default address if there is NO correspon-
4461 ding setting in the environment; if the corresponding environment
4462 variable is set, this overrides the settings in the card; that means:
4464 o If the SROM has a valid MAC address, and there is no address in the
4465 environment, the SROM's address is used.
4467 o If there is no valid address in the SROM, and a definition in the
4468 environment exists, then the value from the environment variable is
4471 o If both the SROM and the environment contain a MAC address, and
4472 both addresses are the same, this MAC address is used.
4474 o If both the SROM and the environment contain a MAC address, and the
4475 addresses differ, the value from the environment is used and a
4478 o If neither SROM nor the environment contain a MAC address, an error
4481 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4482 will be programmed into hardware as part of the initialization process. This
4483 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4484 The naming convention is as follows:
4485 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4490 U-Boot is capable of booting (and performing other auxiliary operations on)
4491 images in two formats:
4493 New uImage format (FIT)
4494 -----------------------
4496 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4497 to Flattened Device Tree). It allows the use of images with multiple
4498 components (several kernels, ramdisks, etc.), with contents protected by
4499 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4505 Old image format is based on binary files which can be basically anything,
4506 preceded by a special header; see the definitions in include/image.h for
4507 details; basically, the header defines the following image properties:
4509 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4510 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4511 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4512 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4514 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4515 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4516 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4517 * Compression Type (uncompressed, gzip, bzip2)
4523 The header is marked by a special Magic Number, and both the header
4524 and the data portions of the image are secured against corruption by
4531 Although U-Boot should support any OS or standalone application
4532 easily, the main focus has always been on Linux during the design of
4535 U-Boot includes many features that so far have been part of some
4536 special "boot loader" code within the Linux kernel. Also, any
4537 "initrd" images to be used are no longer part of one big Linux image;
4538 instead, kernel and "initrd" are separate images. This implementation
4539 serves several purposes:
4541 - the same features can be used for other OS or standalone
4542 applications (for instance: using compressed images to reduce the
4543 Flash memory footprint)
4545 - it becomes much easier to port new Linux kernel versions because
4546 lots of low-level, hardware dependent stuff are done by U-Boot
4548 - the same Linux kernel image can now be used with different "initrd"
4549 images; of course this also means that different kernel images can
4550 be run with the same "initrd". This makes testing easier (you don't
4551 have to build a new "zImage.initrd" Linux image when you just
4552 change a file in your "initrd"). Also, a field-upgrade of the
4553 software is easier now.
4559 Porting Linux to U-Boot based systems:
4560 ---------------------------------------
4562 U-Boot cannot save you from doing all the necessary modifications to
4563 configure the Linux device drivers for use with your target hardware
4564 (no, we don't intend to provide a full virtual machine interface to
4567 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4569 Just make sure your machine specific header file (for instance
4570 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4571 Information structure as we define in include/asm-<arch>/u-boot.h,
4572 and make sure that your definition of IMAP_ADDR uses the same value
4573 as your U-Boot configuration in CONFIG_SYS_IMMR.
4576 Configuring the Linux kernel:
4577 -----------------------------
4579 No specific requirements for U-Boot. Make sure you have some root
4580 device (initial ramdisk, NFS) for your target system.
4583 Building a Linux Image:
4584 -----------------------
4586 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4587 not used. If you use recent kernel source, a new build target
4588 "uImage" will exist which automatically builds an image usable by
4589 U-Boot. Most older kernels also have support for a "pImage" target,
4590 which was introduced for our predecessor project PPCBoot and uses a
4591 100% compatible format.
4600 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4601 encapsulate a compressed Linux kernel image with header information,
4602 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4604 * build a standard "vmlinux" kernel image (in ELF binary format):
4606 * convert the kernel into a raw binary image:
4608 ${CROSS_COMPILE}-objcopy -O binary \
4609 -R .note -R .comment \
4610 -S vmlinux linux.bin
4612 * compress the binary image:
4616 * package compressed binary image for U-Boot:
4618 mkimage -A ppc -O linux -T kernel -C gzip \
4619 -a 0 -e 0 -n "Linux Kernel Image" \
4620 -d linux.bin.gz uImage
4623 The "mkimage" tool can also be used to create ramdisk images for use
4624 with U-Boot, either separated from the Linux kernel image, or
4625 combined into one file. "mkimage" encapsulates the images with a 64
4626 byte header containing information about target architecture,
4627 operating system, image type, compression method, entry points, time
4628 stamp, CRC32 checksums, etc.
4630 "mkimage" can be called in two ways: to verify existing images and
4631 print the header information, or to build new images.
4633 In the first form (with "-l" option) mkimage lists the information
4634 contained in the header of an existing U-Boot image; this includes
4635 checksum verification:
4637 tools/mkimage -l image
4638 -l ==> list image header information
4640 The second form (with "-d" option) is used to build a U-Boot image
4641 from a "data file" which is used as image payload:
4643 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4644 -n name -d data_file image
4645 -A ==> set architecture to 'arch'
4646 -O ==> set operating system to 'os'
4647 -T ==> set image type to 'type'
4648 -C ==> set compression type 'comp'
4649 -a ==> set load address to 'addr' (hex)
4650 -e ==> set entry point to 'ep' (hex)
4651 -n ==> set image name to 'name'
4652 -d ==> use image data from 'datafile'
4654 Right now, all Linux kernels for PowerPC systems use the same load
4655 address (0x00000000), but the entry point address depends on the
4658 - 2.2.x kernels have the entry point at 0x0000000C,
4659 - 2.3.x and later kernels have the entry point at 0x00000000.
4661 So a typical call to build a U-Boot image would read:
4663 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4664 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4665 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4666 > examples/uImage.TQM850L
4667 Image Name: 2.4.4 kernel for TQM850L
4668 Created: Wed Jul 19 02:34:59 2000
4669 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4670 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4671 Load Address: 0x00000000
4672 Entry Point: 0x00000000
4674 To verify the contents of the image (or check for corruption):
4676 -> tools/mkimage -l examples/uImage.TQM850L
4677 Image Name: 2.4.4 kernel for TQM850L
4678 Created: Wed Jul 19 02:34:59 2000
4679 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4680 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4681 Load Address: 0x00000000
4682 Entry Point: 0x00000000
4684 NOTE: for embedded systems where boot time is critical you can trade
4685 speed for memory and install an UNCOMPRESSED image instead: this
4686 needs more space in Flash, but boots much faster since it does not
4687 need to be uncompressed:
4689 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4690 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4691 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4692 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4693 > examples/uImage.TQM850L-uncompressed
4694 Image Name: 2.4.4 kernel for TQM850L
4695 Created: Wed Jul 19 02:34:59 2000
4696 Image Type: PowerPC Linux Kernel Image (uncompressed)
4697 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4698 Load Address: 0x00000000
4699 Entry Point: 0x00000000
4702 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4703 when your kernel is intended to use an initial ramdisk:
4705 -> tools/mkimage -n 'Simple Ramdisk Image' \
4706 > -A ppc -O linux -T ramdisk -C gzip \
4707 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4708 Image Name: Simple Ramdisk Image
4709 Created: Wed Jan 12 14:01:50 2000
4710 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4711 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4712 Load Address: 0x00000000
4713 Entry Point: 0x00000000
4716 Installing a Linux Image:
4717 -------------------------
4719 To downloading a U-Boot image over the serial (console) interface,
4720 you must convert the image to S-Record format:
4722 objcopy -I binary -O srec examples/image examples/image.srec
4724 The 'objcopy' does not understand the information in the U-Boot
4725 image header, so the resulting S-Record file will be relative to
4726 address 0x00000000. To load it to a given address, you need to
4727 specify the target address as 'offset' parameter with the 'loads'
4730 Example: install the image to address 0x40100000 (which on the
4731 TQM8xxL is in the first Flash bank):
4733 => erase 40100000 401FFFFF
4739 ## Ready for S-Record download ...
4740 ~>examples/image.srec
4741 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4743 15989 15990 15991 15992
4744 [file transfer complete]
4746 ## Start Addr = 0x00000000
4749 You can check the success of the download using the 'iminfo' command;
4750 this includes a checksum verification so you can be sure no data
4751 corruption happened:
4755 ## Checking Image at 40100000 ...
4756 Image Name: 2.2.13 for initrd on TQM850L
4757 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4758 Data Size: 335725 Bytes = 327 kB = 0 MB
4759 Load Address: 00000000
4760 Entry Point: 0000000c
4761 Verifying Checksum ... OK
4767 The "bootm" command is used to boot an application that is stored in
4768 memory (RAM or Flash). In case of a Linux kernel image, the contents
4769 of the "bootargs" environment variable is passed to the kernel as
4770 parameters. You can check and modify this variable using the
4771 "printenv" and "setenv" commands:
4774 => printenv bootargs
4775 bootargs=root=/dev/ram
4777 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4779 => printenv bootargs
4780 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4783 ## Booting Linux kernel at 40020000 ...
4784 Image Name: 2.2.13 for NFS on TQM850L
4785 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4786 Data Size: 381681 Bytes = 372 kB = 0 MB
4787 Load Address: 00000000
4788 Entry Point: 0000000c
4789 Verifying Checksum ... OK
4790 Uncompressing Kernel Image ... OK
4791 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
4792 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4793 time_init: decrementer frequency = 187500000/60
4794 Calibrating delay loop... 49.77 BogoMIPS
4795 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4798 If you want to boot a Linux kernel with initial RAM disk, you pass
4799 the memory addresses of both the kernel and the initrd image (PPBCOOT
4800 format!) to the "bootm" command:
4802 => imi 40100000 40200000
4804 ## Checking Image at 40100000 ...
4805 Image Name: 2.2.13 for initrd on TQM850L
4806 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4807 Data Size: 335725 Bytes = 327 kB = 0 MB
4808 Load Address: 00000000
4809 Entry Point: 0000000c
4810 Verifying Checksum ... OK
4812 ## Checking Image at 40200000 ...
4813 Image Name: Simple Ramdisk Image
4814 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4815 Data Size: 566530 Bytes = 553 kB = 0 MB
4816 Load Address: 00000000
4817 Entry Point: 00000000
4818 Verifying Checksum ... OK
4820 => bootm 40100000 40200000
4821 ## Booting Linux kernel at 40100000 ...
4822 Image Name: 2.2.13 for initrd on TQM850L
4823 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4824 Data Size: 335725 Bytes = 327 kB = 0 MB
4825 Load Address: 00000000
4826 Entry Point: 0000000c
4827 Verifying Checksum ... OK
4828 Uncompressing Kernel Image ... OK
4829 ## Loading RAMDisk Image at 40200000 ...
4830 Image Name: Simple Ramdisk Image
4831 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4832 Data Size: 566530 Bytes = 553 kB = 0 MB
4833 Load Address: 00000000
4834 Entry Point: 00000000
4835 Verifying Checksum ... OK
4836 Loading Ramdisk ... OK
4837 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
4838 Boot arguments: root=/dev/ram
4839 time_init: decrementer frequency = 187500000/60
4840 Calibrating delay loop... 49.77 BogoMIPS
4842 RAMDISK: Compressed image found at block 0
4843 VFS: Mounted root (ext2 filesystem).
4847 Boot Linux and pass a flat device tree:
4850 First, U-Boot must be compiled with the appropriate defines. See the section
4851 titled "Linux Kernel Interface" above for a more in depth explanation. The
4852 following is an example of how to start a kernel and pass an updated
4858 oft=oftrees/mpc8540ads.dtb
4859 => tftp $oftaddr $oft
4860 Speed: 1000, full duplex
4862 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4863 Filename 'oftrees/mpc8540ads.dtb'.
4864 Load address: 0x300000
4867 Bytes transferred = 4106 (100a hex)
4868 => tftp $loadaddr $bootfile
4869 Speed: 1000, full duplex
4871 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4873 Load address: 0x200000
4874 Loading:############
4876 Bytes transferred = 1029407 (fb51f hex)
4881 => bootm $loadaddr - $oftaddr
4882 ## Booting image at 00200000 ...
4883 Image Name: Linux-2.6.17-dirty
4884 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4885 Data Size: 1029343 Bytes = 1005.2 kB
4886 Load Address: 00000000
4887 Entry Point: 00000000
4888 Verifying Checksum ... OK
4889 Uncompressing Kernel Image ... OK
4890 Booting using flat device tree at 0x300000
4891 Using MPC85xx ADS machine description
4892 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4896 More About U-Boot Image Types:
4897 ------------------------------
4899 U-Boot supports the following image types:
4901 "Standalone Programs" are directly runnable in the environment
4902 provided by U-Boot; it is expected that (if they behave
4903 well) you can continue to work in U-Boot after return from
4904 the Standalone Program.
4905 "OS Kernel Images" are usually images of some Embedded OS which
4906 will take over control completely. Usually these programs
4907 will install their own set of exception handlers, device
4908 drivers, set up the MMU, etc. - this means, that you cannot
4909 expect to re-enter U-Boot except by resetting the CPU.
4910 "RAMDisk Images" are more or less just data blocks, and their
4911 parameters (address, size) are passed to an OS kernel that is
4913 "Multi-File Images" contain several images, typically an OS
4914 (Linux) kernel image and one or more data images like
4915 RAMDisks. This construct is useful for instance when you want
4916 to boot over the network using BOOTP etc., where the boot
4917 server provides just a single image file, but you want to get
4918 for instance an OS kernel and a RAMDisk image.
4920 "Multi-File Images" start with a list of image sizes, each
4921 image size (in bytes) specified by an "uint32_t" in network
4922 byte order. This list is terminated by an "(uint32_t)0".
4923 Immediately after the terminating 0 follow the images, one by
4924 one, all aligned on "uint32_t" boundaries (size rounded up to
4925 a multiple of 4 bytes).
4927 "Firmware Images" are binary images containing firmware (like
4928 U-Boot or FPGA images) which usually will be programmed to
4931 "Script files" are command sequences that will be executed by
4932 U-Boot's command interpreter; this feature is especially
4933 useful when you configure U-Boot to use a real shell (hush)
4934 as command interpreter.
4936 Booting the Linux zImage:
4937 -------------------------
4939 On some platforms, it's possible to boot Linux zImage. This is done
4940 using the "bootz" command. The syntax of "bootz" command is the same
4941 as the syntax of "bootm" command.
4943 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4944 kernel with raw initrd images. The syntax is slightly different, the
4945 address of the initrd must be augmented by it's size, in the following
4946 format: "<initrd addres>:<initrd size>".
4952 One of the features of U-Boot is that you can dynamically load and
4953 run "standalone" applications, which can use some resources of
4954 U-Boot like console I/O functions or interrupt services.
4956 Two simple examples are included with the sources:
4961 'examples/hello_world.c' contains a small "Hello World" Demo
4962 application; it is automatically compiled when you build U-Boot.
4963 It's configured to run at address 0x00040004, so you can play with it
4967 ## Ready for S-Record download ...
4968 ~>examples/hello_world.srec
4969 1 2 3 4 5 6 7 8 9 10 11 ...
4970 [file transfer complete]
4972 ## Start Addr = 0x00040004
4974 => go 40004 Hello World! This is a test.
4975 ## Starting application at 0x00040004 ...
4986 Hit any key to exit ...
4988 ## Application terminated, rc = 0x0
4990 Another example, which demonstrates how to register a CPM interrupt
4991 handler with the U-Boot code, can be found in 'examples/timer.c'.
4992 Here, a CPM timer is set up to generate an interrupt every second.
4993 The interrupt service routine is trivial, just printing a '.'
4994 character, but this is just a demo program. The application can be
4995 controlled by the following keys:
4997 ? - print current values og the CPM Timer registers
4998 b - enable interrupts and start timer
4999 e - stop timer and disable interrupts
5000 q - quit application
5003 ## Ready for S-Record download ...
5004 ~>examples/timer.srec
5005 1 2 3 4 5 6 7 8 9 10 11 ...
5006 [file transfer complete]
5008 ## Start Addr = 0x00040004
5011 ## Starting application at 0x00040004 ...
5014 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5017 [q, b, e, ?] Set interval 1000000 us
5020 [q, b, e, ?] ........
5021 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5024 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5027 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5030 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5032 [q, b, e, ?] ...Stopping timer
5034 [q, b, e, ?] ## Application terminated, rc = 0x0
5040 Over time, many people have reported problems when trying to use the
5041 "minicom" terminal emulation program for serial download. I (wd)
5042 consider minicom to be broken, and recommend not to use it. Under
5043 Unix, I recommend to use C-Kermit for general purpose use (and
5044 especially for kermit binary protocol download ("loadb" command), and
5045 use "cu" for S-Record download ("loads" command). See
5046 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5047 for help with kermit.
5050 Nevertheless, if you absolutely want to use it try adding this
5051 configuration to your "File transfer protocols" section:
5053 Name Program Name U/D FullScr IO-Red. Multi
5054 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5055 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5061 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5062 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5064 Building requires a cross environment; it is known to work on
5065 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5066 need gmake since the Makefiles are not compatible with BSD make).
5067 Note that the cross-powerpc package does not install include files;
5068 attempting to build U-Boot will fail because <machine/ansi.h> is
5069 missing. This file has to be installed and patched manually:
5071 # cd /usr/pkg/cross/powerpc-netbsd/include
5073 # ln -s powerpc machine
5074 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5075 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5077 Native builds *don't* work due to incompatibilities between native
5078 and U-Boot include files.
5080 Booting assumes that (the first part of) the image booted is a
5081 stage-2 loader which in turn loads and then invokes the kernel
5082 proper. Loader sources will eventually appear in the NetBSD source
5083 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5084 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5087 Implementation Internals:
5088 =========================
5090 The following is not intended to be a complete description of every
5091 implementation detail. However, it should help to understand the
5092 inner workings of U-Boot and make it easier to port it to custom
5096 Initial Stack, Global Data:
5097 ---------------------------
5099 The implementation of U-Boot is complicated by the fact that U-Boot
5100 starts running out of ROM (flash memory), usually without access to
5101 system RAM (because the memory controller is not initialized yet).
5102 This means that we don't have writable Data or BSS segments, and BSS
5103 is not initialized as zero. To be able to get a C environment working
5104 at all, we have to allocate at least a minimal stack. Implementation
5105 options for this are defined and restricted by the CPU used: Some CPU
5106 models provide on-chip memory (like the IMMR area on MPC8xx and
5107 MPC826x processors), on others (parts of) the data cache can be
5108 locked as (mis-) used as memory, etc.
5110 Chris Hallinan posted a good summary of these issues to the
5111 U-Boot mailing list:
5113 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5114 From: "Chris Hallinan" <clh@net1plus.com>
5115 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5118 Correct me if I'm wrong, folks, but the way I understand it
5119 is this: Using DCACHE as initial RAM for Stack, etc, does not
5120 require any physical RAM backing up the cache. The cleverness
5121 is that the cache is being used as a temporary supply of
5122 necessary storage before the SDRAM controller is setup. It's
5123 beyond the scope of this list to explain the details, but you
5124 can see how this works by studying the cache architecture and
5125 operation in the architecture and processor-specific manuals.
5127 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5128 is another option for the system designer to use as an
5129 initial stack/RAM area prior to SDRAM being available. Either
5130 option should work for you. Using CS 4 should be fine if your
5131 board designers haven't used it for something that would
5132 cause you grief during the initial boot! It is frequently not
5135 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5136 with your processor/board/system design. The default value
5137 you will find in any recent u-boot distribution in
5138 walnut.h should work for you. I'd set it to a value larger
5139 than your SDRAM module. If you have a 64MB SDRAM module, set
5140 it above 400_0000. Just make sure your board has no resources
5141 that are supposed to respond to that address! That code in
5142 start.S has been around a while and should work as is when
5143 you get the config right.
5148 It is essential to remember this, since it has some impact on the C
5149 code for the initialization procedures:
5151 * Initialized global data (data segment) is read-only. Do not attempt
5154 * Do not use any uninitialized global data (or implicitely initialized
5155 as zero data - BSS segment) at all - this is undefined, initiali-
5156 zation is performed later (when relocating to RAM).
5158 * Stack space is very limited. Avoid big data buffers or things like
5161 Having only the stack as writable memory limits means we cannot use
5162 normal global data to share information beween the code. But it
5163 turned out that the implementation of U-Boot can be greatly
5164 simplified by making a global data structure (gd_t) available to all
5165 functions. We could pass a pointer to this data as argument to _all_
5166 functions, but this would bloat the code. Instead we use a feature of
5167 the GCC compiler (Global Register Variables) to share the data: we
5168 place a pointer (gd) to the global data into a register which we
5169 reserve for this purpose.
5171 When choosing a register for such a purpose we are restricted by the
5172 relevant (E)ABI specifications for the current architecture, and by
5173 GCC's implementation.
5175 For PowerPC, the following registers have specific use:
5177 R2: reserved for system use
5178 R3-R4: parameter passing and return values
5179 R5-R10: parameter passing
5180 R13: small data area pointer
5184 (U-Boot also uses R12 as internal GOT pointer. r12
5185 is a volatile register so r12 needs to be reset when
5186 going back and forth between asm and C)
5188 ==> U-Boot will use R2 to hold a pointer to the global data
5190 Note: on PPC, we could use a static initializer (since the
5191 address of the global data structure is known at compile time),
5192 but it turned out that reserving a register results in somewhat
5193 smaller code - although the code savings are not that big (on
5194 average for all boards 752 bytes for the whole U-Boot image,
5195 624 text + 127 data).
5197 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5198 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5200 ==> U-Boot will use P3 to hold a pointer to the global data
5202 On ARM, the following registers are used:
5204 R0: function argument word/integer result
5205 R1-R3: function argument word
5207 R10: stack limit (used only if stack checking if enabled)
5208 R11: argument (frame) pointer
5209 R12: temporary workspace
5212 R15: program counter
5214 ==> U-Boot will use R8 to hold a pointer to the global data
5216 On Nios II, the ABI is documented here:
5217 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5219 ==> U-Boot will use gp to hold a pointer to the global data
5221 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5222 to access small data sections, so gp is free.
5224 On NDS32, the following registers are used:
5226 R0-R1: argument/return
5228 R15: temporary register for assembler
5229 R16: trampoline register
5230 R28: frame pointer (FP)
5231 R29: global pointer (GP)
5232 R30: link register (LP)
5233 R31: stack pointer (SP)
5234 PC: program counter (PC)
5236 ==> U-Boot will use R10 to hold a pointer to the global data
5238 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5239 or current versions of GCC may "optimize" the code too much.
5244 U-Boot runs in system state and uses physical addresses, i.e. the
5245 MMU is not used either for address mapping nor for memory protection.
5247 The available memory is mapped to fixed addresses using the memory
5248 controller. In this process, a contiguous block is formed for each
5249 memory type (Flash, SDRAM, SRAM), even when it consists of several
5250 physical memory banks.
5252 U-Boot is installed in the first 128 kB of the first Flash bank (on
5253 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5254 booting and sizing and initializing DRAM, the code relocates itself
5255 to the upper end of DRAM. Immediately below the U-Boot code some
5256 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5257 configuration setting]. Below that, a structure with global Board
5258 Info data is placed, followed by the stack (growing downward).
5260 Additionally, some exception handler code is copied to the low 8 kB
5261 of DRAM (0x00000000 ... 0x00001FFF).
5263 So a typical memory configuration with 16 MB of DRAM could look like
5266 0x0000 0000 Exception Vector code
5269 0x0000 2000 Free for Application Use
5275 0x00FB FF20 Monitor Stack (Growing downward)
5276 0x00FB FFAC Board Info Data and permanent copy of global data
5277 0x00FC 0000 Malloc Arena
5280 0x00FE 0000 RAM Copy of Monitor Code
5281 ... eventually: LCD or video framebuffer
5282 ... eventually: pRAM (Protected RAM - unchanged by reset)
5283 0x00FF FFFF [End of RAM]
5286 System Initialization:
5287 ----------------------
5289 In the reset configuration, U-Boot starts at the reset entry point
5290 (on most PowerPC systems at address 0x00000100). Because of the reset
5291 configuration for CS0# this is a mirror of the onboard Flash memory.
5292 To be able to re-map memory U-Boot then jumps to its link address.
5293 To be able to implement the initialization code in C, a (small!)
5294 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5295 which provide such a feature like MPC8xx or MPC8260), or in a locked
5296 part of the data cache. After that, U-Boot initializes the CPU core,
5297 the caches and the SIU.
5299 Next, all (potentially) available memory banks are mapped using a
5300 preliminary mapping. For example, we put them on 512 MB boundaries
5301 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5302 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5303 programmed for SDRAM access. Using the temporary configuration, a
5304 simple memory test is run that determines the size of the SDRAM
5307 When there is more than one SDRAM bank, and the banks are of
5308 different size, the largest is mapped first. For equal size, the first
5309 bank (CS2#) is mapped first. The first mapping is always for address
5310 0x00000000, with any additional banks following immediately to create
5311 contiguous memory starting from 0.
5313 Then, the monitor installs itself at the upper end of the SDRAM area
5314 and allocates memory for use by malloc() and for the global Board
5315 Info data; also, the exception vector code is copied to the low RAM
5316 pages, and the final stack is set up.
5318 Only after this relocation will you have a "normal" C environment;
5319 until that you are restricted in several ways, mostly because you are
5320 running from ROM, and because the code will have to be relocated to a
5324 U-Boot Porting Guide:
5325 ----------------------
5327 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5331 int main(int argc, char *argv[])
5333 sighandler_t no_more_time;
5335 signal(SIGALRM, no_more_time);
5336 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5338 if (available_money > available_manpower) {
5339 Pay consultant to port U-Boot;
5343 Download latest U-Boot source;
5345 Subscribe to u-boot mailing list;
5348 email("Hi, I am new to U-Boot, how do I get started?");
5351 Read the README file in the top level directory;
5352 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5353 Read applicable doc/*.README;
5354 Read the source, Luke;
5355 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5358 if (available_money > toLocalCurrency ($2500))
5361 Add a lot of aggravation and time;
5363 if (a similar board exists) { /* hopefully... */
5364 cp -a board/<similar> board/<myboard>
5365 cp include/configs/<similar>.h include/configs/<myboard>.h
5367 Create your own board support subdirectory;
5368 Create your own board include/configs/<myboard>.h file;
5370 Edit new board/<myboard> files
5371 Edit new include/configs/<myboard>.h
5376 Add / modify source code;
5380 email("Hi, I am having problems...");
5382 Send patch file to the U-Boot email list;
5383 if (reasonable critiques)
5384 Incorporate improvements from email list code review;
5386 Defend code as written;
5392 void no_more_time (int sig)
5401 All contributions to U-Boot should conform to the Linux kernel
5402 coding style; see the file "Documentation/CodingStyle" and the script
5403 "scripts/Lindent" in your Linux kernel source directory.
5405 Source files originating from a different project (for example the
5406 MTD subsystem) are generally exempt from these guidelines and are not
5407 reformated to ease subsequent migration to newer versions of those
5410 Please note that U-Boot is implemented in C (and to some small parts in
5411 Assembler); no C++ is used, so please do not use C++ style comments (//)
5414 Please also stick to the following formatting rules:
5415 - remove any trailing white space
5416 - use TAB characters for indentation and vertical alignment, not spaces
5417 - make sure NOT to use DOS '\r\n' line feeds
5418 - do not add more than 2 consecutive empty lines to source files
5419 - do not add trailing empty lines to source files
5421 Submissions which do not conform to the standards may be returned
5422 with a request to reformat the changes.
5428 Since the number of patches for U-Boot is growing, we need to
5429 establish some rules. Submissions which do not conform to these rules
5430 may be rejected, even when they contain important and valuable stuff.
5432 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5434 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5435 see http://lists.denx.de/mailman/listinfo/u-boot
5437 When you send a patch, please include the following information with
5440 * For bug fixes: a description of the bug and how your patch fixes
5441 this bug. Please try to include a way of demonstrating that the
5442 patch actually fixes something.
5444 * For new features: a description of the feature and your
5447 * A CHANGELOG entry as plaintext (separate from the patch)
5449 * For major contributions, your entry to the CREDITS file
5451 * When you add support for a new board, don't forget to add this
5452 board to the MAINTAINERS file, too.
5454 * If your patch adds new configuration options, don't forget to
5455 document these in the README file.
5457 * The patch itself. If you are using git (which is *strongly*
5458 recommended) you can easily generate the patch using the
5459 "git format-patch". If you then use "git send-email" to send it to
5460 the U-Boot mailing list, you will avoid most of the common problems
5461 with some other mail clients.
5463 If you cannot use git, use "diff -purN OLD NEW". If your version of
5464 diff does not support these options, then get the latest version of
5467 The current directory when running this command shall be the parent
5468 directory of the U-Boot source tree (i. e. please make sure that
5469 your patch includes sufficient directory information for the
5472 We prefer patches as plain text. MIME attachments are discouraged,
5473 and compressed attachments must not be used.
5475 * If one logical set of modifications affects or creates several
5476 files, all these changes shall be submitted in a SINGLE patch file.
5478 * Changesets that contain different, unrelated modifications shall be
5479 submitted as SEPARATE patches, one patch per changeset.
5484 * Before sending the patch, run the MAKEALL script on your patched
5485 source tree and make sure that no errors or warnings are reported
5486 for any of the boards.
5488 * Keep your modifications to the necessary minimum: A patch
5489 containing several unrelated changes or arbitrary reformats will be
5490 returned with a request to re-formatting / split it.
5492 * If you modify existing code, make sure that your new code does not
5493 add to the memory footprint of the code ;-) Small is beautiful!
5494 When adding new features, these should compile conditionally only
5495 (using #ifdef), and the resulting code with the new feature
5496 disabled must not need more memory than the old code without your
5499 * Remember that there is a size limit of 100 kB per message on the
5500 u-boot mailing list. Bigger patches will be moderated. If they are
5501 reasonable and not too big, they will be acknowledged. But patches
5502 bigger than the size limit should be avoided.