2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arm Files generic to ARM architecture
136 /cpu CPU specific files
137 /arm720t Files specific to ARM 720 CPUs
138 /arm920t Files specific to ARM 920 CPUs
139 /at91 Files specific to Atmel AT91RM9200 CPU
140 /imx Files specific to Freescale MC9328 i.MX CPUs
141 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
142 /arm926ejs Files specific to ARM 926 CPUs
143 /arm1136 Files specific to ARM 1136 CPUs
144 /ixp Files specific to Intel XScale IXP CPUs
145 /pxa Files specific to Intel XScale PXA CPUs
146 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
147 /lib Architecture specific library files
148 /avr32 Files generic to AVR32 architecture
149 /cpu CPU specific files
150 /lib Architecture specific library files
151 /blackfin Files generic to Analog Devices Blackfin architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /m68k Files generic to m68k architecture
155 /cpu CPU specific files
156 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
157 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
158 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
159 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
160 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
161 /lib Architecture specific library files
162 /microblaze Files generic to microblaze architecture
163 /cpu CPU specific files
164 /lib Architecture specific library files
165 /mips Files generic to MIPS architecture
166 /cpu CPU specific files
167 /mips32 Files specific to MIPS32 CPUs
168 /xburst Files specific to Ingenic XBurst CPUs
169 /lib Architecture specific library files
170 /nds32 Files generic to NDS32 architecture
171 /cpu CPU specific files
172 /n1213 Files specific to Andes Technology N1213 CPUs
173 /lib Architecture specific library files
174 /nios2 Files generic to Altera NIOS2 architecture
175 /cpu CPU specific files
176 /lib Architecture specific library files
177 /openrisc Files generic to OpenRISC architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /powerpc Files generic to PowerPC architecture
181 /cpu CPU specific files
182 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
183 /mpc5xx Files specific to Freescale MPC5xx CPUs
184 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
185 /mpc8xx Files specific to Freescale MPC8xx CPUs
186 /mpc824x Files specific to Freescale MPC824x CPUs
187 /mpc8260 Files specific to Freescale MPC8260 CPUs
188 /mpc85xx Files specific to Freescale MPC85xx CPUs
189 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
190 /lib Architecture specific library files
191 /sh Files generic to SH architecture
192 /cpu CPU specific files
193 /sh2 Files specific to sh2 CPUs
194 /sh3 Files specific to sh3 CPUs
195 /sh4 Files specific to sh4 CPUs
196 /lib Architecture specific library files
197 /sparc Files generic to SPARC architecture
198 /cpu CPU specific files
199 /leon2 Files specific to Gaisler LEON2 SPARC CPU
200 /leon3 Files specific to Gaisler LEON3 SPARC CPU
201 /lib Architecture specific library files
202 /x86 Files generic to x86 architecture
203 /cpu CPU specific files
204 /lib Architecture specific library files
205 /api Machine/arch independent API for external apps
206 /board Board dependent files
207 /common Misc architecture independent functions
208 /disk Code for disk drive partition handling
209 /doc Documentation (don't expect too much)
210 /drivers Commonly used device drivers
211 /dts Contains Makefile for building internal U-Boot fdt.
212 /examples Example code for standalone applications, etc.
213 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
214 /include Header Files
215 /lib Files generic to all architectures
216 /libfdt Library files to support flattened device trees
217 /lzma Library files to support LZMA decompression
218 /lzo Library files to support LZO decompression
220 /post Power On Self Test
221 /spl Secondary Program Loader framework
222 /tools Tools to build S-Record or U-Boot images, etc.
224 Software Configuration:
225 =======================
227 Configuration is usually done using C preprocessor defines; the
228 rationale behind that is to avoid dead code whenever possible.
230 There are two classes of configuration variables:
232 * Configuration _OPTIONS_:
233 These are selectable by the user and have names beginning with
236 * Configuration _SETTINGS_:
237 These depend on the hardware etc. and should not be meddled with if
238 you don't know what you're doing; they have names beginning with
241 Later we will add a configuration tool - probably similar to or even
242 identical to what's used for the Linux kernel. Right now, we have to
243 do the configuration by hand, which means creating some symbolic
244 links and editing some configuration files. We use the TQM8xxL boards
248 Selection of Processor Architecture and Board Type:
249 ---------------------------------------------------
251 For all supported boards there are ready-to-use default
252 configurations available; just type "make <board_name>_config".
254 Example: For a TQM823L module type:
259 For the Cogent platform, you need to specify the CPU type as well;
260 e.g. "make cogent_mpc8xx_config". And also configure the cogent
261 directory according to the instructions in cogent/README.
264 Configuration Options:
265 ----------------------
267 Configuration depends on the combination of board and CPU type; all
268 such information is kept in a configuration file
269 "include/configs/<board_name>.h".
271 Example: For a TQM823L module, all configuration settings are in
272 "include/configs/TQM823L.h".
275 Many of the options are named exactly as the corresponding Linux
276 kernel configuration options. The intention is to make it easier to
277 build a config tool - later.
280 The following options need to be configured:
282 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
284 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
286 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
287 Define exactly one, e.g. CONFIG_ATSTK1002
289 - CPU Module Type: (if CONFIG_COGENT is defined)
290 Define exactly one of
292 --- FIXME --- not tested yet:
293 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
294 CONFIG_CMA287_23, CONFIG_CMA287_50
296 - Motherboard Type: (if CONFIG_COGENT is defined)
297 Define exactly one of
298 CONFIG_CMA101, CONFIG_CMA102
300 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
301 Define one or more of
304 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
305 Define one or more of
306 CONFIG_LCD_HEARTBEAT - update a character position on
307 the LCD display every second with
310 - Board flavour: (if CONFIG_MPC8260ADS is defined)
313 CONFIG_SYS_8260ADS - original MPC8260ADS
314 CONFIG_SYS_8266ADS - MPC8266ADS
315 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
316 CONFIG_SYS_8272ADS - MPC8272ADS
318 - Marvell Family Member
319 CONFIG_SYS_MVFS - define it if you want to enable
320 multiple fs option at one time
321 for marvell soc family
323 - MPC824X Family Member (if CONFIG_MPC824X is defined)
324 Define exactly one of
325 CONFIG_MPC8240, CONFIG_MPC8245
327 - 8xx CPU Options: (if using an MPC8xx CPU)
328 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
329 get_gclk_freq() cannot work
330 e.g. if there is no 32KHz
331 reference PIT/RTC clock
332 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
335 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
336 CONFIG_SYS_8xx_CPUCLK_MIN
337 CONFIG_SYS_8xx_CPUCLK_MAX
338 CONFIG_8xx_CPUCLK_DEFAULT
339 See doc/README.MPC866
341 CONFIG_SYS_MEASURE_CPUCLK
343 Define this to measure the actual CPU clock instead
344 of relying on the correctness of the configured
345 values. Mostly useful for board bringup to make sure
346 the PLL is locked at the intended frequency. Note
347 that this requires a (stable) reference clock (32 kHz
348 RTC clock or CONFIG_SYS_8XX_XIN)
350 CONFIG_SYS_DELAYED_ICACHE
352 Define this option if you want to enable the
353 ICache only when Code runs from RAM.
358 Specifies that the core is a 64-bit PowerPC implementation (implements
359 the "64" category of the Power ISA). This is necessary for ePAPR
360 compliance, among other possible reasons.
362 CONFIG_SYS_FSL_TBCLK_DIV
364 Defines the core time base clock divider ratio compared to the
365 system clock. On most PQ3 devices this is 8, on newer QorIQ
366 devices it can be 16 or 32. The ratio varies from SoC to Soc.
368 CONFIG_SYS_FSL_PCIE_COMPAT
370 Defines the string to utilize when trying to match PCIe device
371 tree nodes for the given platform.
373 CONFIG_SYS_PPC_E500_DEBUG_TLB
375 Enables a temporary TLB entry to be used during boot to work
376 around limitations in e500v1 and e500v2 external debugger
377 support. This reduces the portions of the boot code where
378 breakpoints and single stepping do not work. The value of this
379 symbol should be set to the TLB1 entry to be used for this
382 CONFIG_SYS_FSL_ERRATUM_A004510
384 Enables a workaround for erratum A004510. If set,
385 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
386 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
388 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
389 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
391 Defines one or two SoC revisions (low 8 bits of SVR)
392 for which the A004510 workaround should be applied.
394 The rest of SVR is either not relevant to the decision
395 of whether the erratum is present (e.g. p2040 versus
396 p2041) or is implied by the build target, which controls
397 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
399 See Freescale App Note 4493 for more information about
402 CONFIG_A003399_NOR_WORKAROUND
403 Enables a workaround for IFC erratum A003399. It is only
404 requred during NOR boot.
406 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
408 This is the value to write into CCSR offset 0x18600
409 according to the A004510 workaround.
411 CONFIG_SYS_FSL_DSP_DDR_ADDR
412 This value denotes start offset of DDR memory which is
413 connected exclusively to the DSP cores.
415 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
416 This value denotes start offset of M2 memory
417 which is directly connected to the DSP core.
419 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
420 This value denotes start offset of M3 memory which is directly
421 connected to the DSP core.
423 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
424 This value denotes start offset of DSP CCSR space.
426 - Generic CPU options:
427 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
429 Defines the endianess of the CPU. Implementation of those
430 values is arch specific.
433 Freescale DDR driver in use. This type of DDR controller is
434 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
437 CONFIG_SYS_FSL_DDR_ADDR
438 Freescale DDR memory-mapped register base.
440 CONFIG_SYS_FSL_DDR_EMU
441 Specify emulator support for DDR. Some DDR features such as
442 deskew training are not available.
444 CONFIG_SYS_FSL_DDRC_GEN1
445 Freescale DDR1 controller.
447 CONFIG_SYS_FSL_DDRC_GEN2
448 Freescale DDR2 controller.
450 CONFIG_SYS_FSL_DDRC_GEN3
451 Freescale DDR3 controller.
453 CONFIG_SYS_FSL_DDRC_ARM_GEN3
454 Freescale DDR3 controller for ARM-based SoCs.
457 Board config to use DDR1. It can be enabled for SoCs with
458 Freescale DDR1 or DDR2 controllers, depending on the board
462 Board config to use DDR2. It can be eanbeld for SoCs with
463 Freescale DDR2 or DDR3 controllers, depending on the board
467 Board config to use DDR3. It can be enabled for SoCs with
468 Freescale DDR3 controllers.
470 - Intel Monahans options:
471 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
473 Defines the Monahans run mode to oscillator
474 ratio. Valid values are 8, 16, 24, 31. The core
475 frequency is this value multiplied by 13 MHz.
477 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
479 Defines the Monahans turbo mode to oscillator
480 ratio. Valid values are 1 (default if undefined) and
481 2. The core frequency as calculated above is multiplied
485 CONFIG_SYS_INIT_SP_OFFSET
487 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
488 pointer. This is needed for the temporary stack before
491 CONFIG_SYS_MIPS_CACHE_MODE
493 Cache operation mode for the MIPS CPU.
494 See also arch/mips/include/asm/mipsregs.h.
496 CONF_CM_CACHABLE_NO_WA
499 CONF_CM_CACHABLE_NONCOHERENT
503 CONF_CM_CACHABLE_ACCELERATED
505 CONFIG_SYS_XWAY_EBU_BOOTCFG
507 Special option for Lantiq XWAY SoCs for booting from NOR flash.
508 See also arch/mips/cpu/mips32/start.S.
510 CONFIG_XWAY_SWAP_BYTES
512 Enable compilation of tools/xway-swap-bytes needed for Lantiq
513 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
514 be swapped if a flash programmer is used.
517 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
519 Select high exception vectors of the ARM core, e.g., do not
520 clear the V bit of the c1 register of CP15.
522 CONFIG_SYS_THUMB_BUILD
524 Use this flag to build U-Boot using the Thumb instruction
525 set for ARM architectures. Thumb instruction set provides
526 better code density. For ARM architectures that support
527 Thumb2 this flag will result in Thumb2 code generated by
530 CONFIG_ARM_ERRATA_716044
531 CONFIG_ARM_ERRATA_742230
532 CONFIG_ARM_ERRATA_743622
533 CONFIG_ARM_ERRATA_751472
535 If set, the workarounds for these ARM errata are applied early
536 during U-Boot startup. Note that these options force the
537 workarounds to be applied; no CPU-type/version detection
538 exists, unlike the similar options in the Linux kernel. Do not
539 set these options unless they apply!
544 The frequency of the timer returned by get_timer().
545 get_timer() must operate in milliseconds and this CONFIG
546 option must be set to 1000.
548 - Linux Kernel Interface:
551 U-Boot stores all clock information in Hz
552 internally. For binary compatibility with older Linux
553 kernels (which expect the clocks passed in the
554 bd_info data to be in MHz) the environment variable
555 "clocks_in_mhz" can be defined so that U-Boot
556 converts clock data to MHZ before passing it to the
558 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
559 "clocks_in_mhz=1" is automatically included in the
562 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
564 When transferring memsize parameter to linux, some versions
565 expect it to be in bytes, others in MB.
566 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
570 New kernel versions are expecting firmware settings to be
571 passed using flattened device trees (based on open firmware
575 * New libfdt-based support
576 * Adds the "fdt" command
577 * The bootm command automatically updates the fdt
579 OF_CPU - The proper name of the cpus node (only required for
580 MPC512X and MPC5xxx based boards).
581 OF_SOC - The proper name of the soc node (only required for
582 MPC512X and MPC5xxx based boards).
583 OF_TBCLK - The timebase frequency.
584 OF_STDOUT_PATH - The path to the console device
586 boards with QUICC Engines require OF_QE to set UCC MAC
589 CONFIG_OF_BOARD_SETUP
591 Board code has addition modification that it wants to make
592 to the flat device tree before handing it off to the kernel
596 This define fills in the correct boot CPU in the boot
597 param header, the default value is zero if undefined.
601 U-Boot can detect if an IDE device is present or not.
602 If not, and this new config option is activated, U-Boot
603 removes the ATA node from the DTS before booting Linux,
604 so the Linux IDE driver does not probe the device and
605 crash. This is needed for buggy hardware (uc101) where
606 no pull down resistor is connected to the signal IDE5V_DD7.
608 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
610 This setting is mandatory for all boards that have only one
611 machine type and must be used to specify the machine type
612 number as it appears in the ARM machine registry
613 (see http://www.arm.linux.org.uk/developer/machines/).
614 Only boards that have multiple machine types supported
615 in a single configuration file and the machine type is
616 runtime discoverable, do not have to use this setting.
618 - vxWorks boot parameters:
620 bootvx constructs a valid bootline using the following
621 environments variables: bootfile, ipaddr, serverip, hostname.
622 It loads the vxWorks image pointed bootfile.
624 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
625 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
626 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
627 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
629 CONFIG_SYS_VXWORKS_ADD_PARAMS
631 Add it at the end of the bootline. E.g "u=username pw=secret"
633 Note: If a "bootargs" environment is defined, it will overwride
634 the defaults discussed just above.
636 - Cache Configuration:
637 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
638 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
639 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
641 - Cache Configuration for ARM:
642 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
644 CONFIG_SYS_PL310_BASE - Physical base address of PL310
645 controller register space
650 Define this if you want support for Amba PrimeCell PL010 UARTs.
654 Define this if you want support for Amba PrimeCell PL011 UARTs.
658 If you have Amba PrimeCell PL011 UARTs, set this variable to
659 the clock speed of the UARTs.
663 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
664 define this to a list of base addresses for each (supported)
665 port. See e.g. include/configs/versatile.h
667 CONFIG_PL011_SERIAL_RLCR
669 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
670 have separate receive and transmit line control registers. Set
671 this variable to initialize the extra register.
673 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
675 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
676 boot loader that has already initialized the UART. Define this
677 variable to flush the UART at init time.
681 Depending on board, define exactly one serial port
682 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
683 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
684 console by defining CONFIG_8xx_CONS_NONE
686 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
687 port routines must be defined elsewhere
688 (i.e. serial_init(), serial_getc(), ...)
691 Enables console device for a color framebuffer. Needs following
692 defines (cf. smiLynxEM, i8042)
693 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
695 VIDEO_HW_RECTFILL graphic chip supports
698 VIDEO_HW_BITBLT graphic chip supports
699 bit-blit (cf. smiLynxEM)
700 VIDEO_VISIBLE_COLS visible pixel columns
702 VIDEO_VISIBLE_ROWS visible pixel rows
703 VIDEO_PIXEL_SIZE bytes per pixel
704 VIDEO_DATA_FORMAT graphic data format
705 (0-5, cf. cfb_console.c)
706 VIDEO_FB_ADRS framebuffer address
707 VIDEO_KBD_INIT_FCT keyboard int fct
708 (i.e. i8042_kbd_init())
709 VIDEO_TSTC_FCT test char fct
711 VIDEO_GETC_FCT get char fct
713 CONFIG_CONSOLE_CURSOR cursor drawing on/off
714 (requires blink timer
716 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
717 CONFIG_CONSOLE_TIME display time/date info in
719 (requires CONFIG_CMD_DATE)
720 CONFIG_VIDEO_LOGO display Linux logo in
722 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
723 linux_logo.h for logo.
724 Requires CONFIG_VIDEO_LOGO
725 CONFIG_CONSOLE_EXTRA_INFO
726 additional board info beside
729 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
730 a limited number of ANSI escape sequences (cursor control,
731 erase functions and limited graphics rendition control).
733 When CONFIG_CFB_CONSOLE is defined, video console is
734 default i/o. Serial console can be forced with
735 environment 'console=serial'.
737 When CONFIG_SILENT_CONSOLE is defined, all console
738 messages (by U-Boot and Linux!) can be silenced with
739 the "silent" environment variable. See
740 doc/README.silent for more information.
742 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
744 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
748 CONFIG_BAUDRATE - in bps
749 Select one of the baudrates listed in
750 CONFIG_SYS_BAUDRATE_TABLE, see below.
751 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
753 - Console Rx buffer length
754 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
755 the maximum receive buffer length for the SMC.
756 This option is actual only for 82xx and 8xx possible.
757 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
758 must be defined, to setup the maximum idle timeout for
761 - Pre-Console Buffer:
762 Prior to the console being initialised (i.e. serial UART
763 initialised etc) all console output is silently discarded.
764 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
765 buffer any console messages prior to the console being
766 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
767 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
768 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
769 bytes are output before the console is initialised, the
770 earlier bytes are discarded.
772 'Sane' compilers will generate smaller code if
773 CONFIG_PRE_CON_BUF_SZ is a power of 2
775 - Safe printf() functions
776 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
777 the printf() functions. These are defined in
778 include/vsprintf.h and include snprintf(), vsnprintf() and
779 so on. Code size increase is approximately 300-500 bytes.
780 If this option is not given then these functions will
781 silently discard their buffer size argument - this means
782 you are not getting any overflow checking in this case.
784 - Boot Delay: CONFIG_BOOTDELAY - in seconds
785 Delay before automatically booting the default image;
786 set to -1 to disable autoboot.
787 set to -2 to autoboot with no delay and not check for abort
788 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
790 See doc/README.autoboot for these options that
791 work with CONFIG_BOOTDELAY. None are required.
792 CONFIG_BOOT_RETRY_TIME
793 CONFIG_BOOT_RETRY_MIN
794 CONFIG_AUTOBOOT_KEYED
795 CONFIG_AUTOBOOT_PROMPT
796 CONFIG_AUTOBOOT_DELAY_STR
797 CONFIG_AUTOBOOT_STOP_STR
798 CONFIG_AUTOBOOT_DELAY_STR2
799 CONFIG_AUTOBOOT_STOP_STR2
800 CONFIG_ZERO_BOOTDELAY_CHECK
801 CONFIG_RESET_TO_RETRY
805 Only needed when CONFIG_BOOTDELAY is enabled;
806 define a command string that is automatically executed
807 when no character is read on the console interface
808 within "Boot Delay" after reset.
811 This can be used to pass arguments to the bootm
812 command. The value of CONFIG_BOOTARGS goes into the
813 environment value "bootargs".
815 CONFIG_RAMBOOT and CONFIG_NFSBOOT
816 The value of these goes into the environment as
817 "ramboot" and "nfsboot" respectively, and can be used
818 as a convenience, when switching between booting from
824 When this option is #defined, the existence of the
825 environment variable "preboot" will be checked
826 immediately before starting the CONFIG_BOOTDELAY
827 countdown and/or running the auto-boot command resp.
828 entering interactive mode.
830 This feature is especially useful when "preboot" is
831 automatically generated or modified. For an example
832 see the LWMON board specific code: here "preboot" is
833 modified when the user holds down a certain
834 combination of keys on the (special) keyboard when
837 - Serial Download Echo Mode:
839 If defined to 1, all characters received during a
840 serial download (using the "loads" command) are
841 echoed back. This might be needed by some terminal
842 emulations (like "cu"), but may as well just take
843 time on others. This setting #define's the initial
844 value of the "loads_echo" environment variable.
846 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
848 Select one of the baudrates listed in
849 CONFIG_SYS_BAUDRATE_TABLE, see below.
852 Monitor commands can be included or excluded
853 from the build by using the #include files
854 <config_cmd_all.h> and #undef'ing unwanted
855 commands, or using <config_cmd_default.h>
856 and augmenting with additional #define's
859 The default command configuration includes all commands
860 except those marked below with a "*".
862 CONFIG_CMD_ASKENV * ask for env variable
863 CONFIG_CMD_BDI bdinfo
864 CONFIG_CMD_BEDBUG * Include BedBug Debugger
865 CONFIG_CMD_BMP * BMP support
866 CONFIG_CMD_BSP * Board specific commands
867 CONFIG_CMD_BOOTD bootd
868 CONFIG_CMD_CACHE * icache, dcache
869 CONFIG_CMD_CONSOLE coninfo
870 CONFIG_CMD_CRC32 * crc32
871 CONFIG_CMD_DATE * support for RTC, date/time...
872 CONFIG_CMD_DHCP * DHCP support
873 CONFIG_CMD_DIAG * Diagnostics
874 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
875 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
876 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
877 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
878 CONFIG_CMD_DTT * Digital Therm and Thermostat
879 CONFIG_CMD_ECHO echo arguments
880 CONFIG_CMD_EDITENV edit env variable
881 CONFIG_CMD_EEPROM * EEPROM read/write support
882 CONFIG_CMD_ELF * bootelf, bootvx
883 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
884 CONFIG_CMD_ENV_FLAGS * display details about env flags
885 CONFIG_CMD_ENV_EXISTS * check existence of env variable
886 CONFIG_CMD_EXPORTENV * export the environment
887 CONFIG_CMD_EXT2 * ext2 command support
888 CONFIG_CMD_EXT4 * ext4 command support
889 CONFIG_CMD_SAVEENV saveenv
890 CONFIG_CMD_FDC * Floppy Disk Support
891 CONFIG_CMD_FAT * FAT command support
892 CONFIG_CMD_FDOS * Dos diskette Support
893 CONFIG_CMD_FLASH flinfo, erase, protect
894 CONFIG_CMD_FPGA FPGA device initialization support
895 CONFIG_CMD_FUSE * Device fuse support
896 CONFIG_CMD_GETTIME * Get time since boot
897 CONFIG_CMD_GO * the 'go' command (exec code)
898 CONFIG_CMD_GREPENV * search environment
899 CONFIG_CMD_HASH * calculate hash / digest
900 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
901 CONFIG_CMD_I2C * I2C serial bus support
902 CONFIG_CMD_IDE * IDE harddisk support
903 CONFIG_CMD_IMI iminfo
904 CONFIG_CMD_IMLS List all images found in NOR flash
905 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
906 CONFIG_CMD_IMMAP * IMMR dump support
907 CONFIG_CMD_IMPORTENV * import an environment
908 CONFIG_CMD_INI * import data from an ini file into the env
909 CONFIG_CMD_IRQ * irqinfo
910 CONFIG_CMD_ITEST Integer/string test of 2 values
911 CONFIG_CMD_JFFS2 * JFFS2 Support
912 CONFIG_CMD_KGDB * kgdb
913 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
914 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
916 CONFIG_CMD_LOADB loadb
917 CONFIG_CMD_LOADS loads
918 CONFIG_CMD_MD5SUM * print md5 message digest
919 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
920 CONFIG_CMD_MEMINFO * Display detailed memory information
921 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
923 CONFIG_CMD_MEMTEST * mtest
924 CONFIG_CMD_MISC Misc functions like sleep etc
925 CONFIG_CMD_MMC * MMC memory mapped support
926 CONFIG_CMD_MII * MII utility commands
927 CONFIG_CMD_MTDPARTS * MTD partition support
928 CONFIG_CMD_NAND * NAND support
929 CONFIG_CMD_NET bootp, tftpboot, rarpboot
930 CONFIG_CMD_NFS NFS support
931 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
932 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
933 CONFIG_CMD_PCI * pciinfo
934 CONFIG_CMD_PCMCIA * PCMCIA support
935 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
937 CONFIG_CMD_PORTIO * Port I/O
938 CONFIG_CMD_READ * Read raw data from partition
939 CONFIG_CMD_REGINFO * Register dump
940 CONFIG_CMD_RUN run command in env variable
941 CONFIG_CMD_SANDBOX * sb command to access sandbox features
942 CONFIG_CMD_SAVES * save S record dump
943 CONFIG_CMD_SCSI * SCSI Support
944 CONFIG_CMD_SDRAM * print SDRAM configuration information
945 (requires CONFIG_CMD_I2C)
946 CONFIG_CMD_SETGETDCR Support for DCR Register access
948 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
949 CONFIG_CMD_SHA1SUM * print sha1 memory digest
950 (requires CONFIG_CMD_MEMORY)
951 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
952 CONFIG_CMD_SOURCE "source" command Support
953 CONFIG_CMD_SPI * SPI serial bus support
954 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
955 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
956 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
957 CONFIG_CMD_TIMER * access to the system tick timer
958 CONFIG_CMD_USB * USB support
959 CONFIG_CMD_CDP * Cisco Discover Protocol support
960 CONFIG_CMD_MFSL * Microblaze FSL support
961 CONFIG_CMD_XIMG Load part of Multi Image
964 EXAMPLE: If you want all functions except of network
965 support you can write:
967 #include "config_cmd_all.h"
968 #undef CONFIG_CMD_NET
971 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
973 Note: Don't enable the "icache" and "dcache" commands
974 (configuration option CONFIG_CMD_CACHE) unless you know
975 what you (and your U-Boot users) are doing. Data
976 cache cannot be enabled on systems like the 8xx or
977 8260 (where accesses to the IMMR region must be
978 uncached), and it cannot be disabled on all other
979 systems where we (mis-) use the data cache to hold an
980 initial stack and some data.
983 XXX - this list needs to get updated!
985 - Regular expression support:
987 If this variable is defined, U-Boot is linked against
988 the SLRE (Super Light Regular Expression) library,
989 which adds regex support to some commands, as for
990 example "env grep" and "setexpr".
994 If this variable is defined, U-Boot will use a device tree
995 to configure its devices, instead of relying on statically
996 compiled #defines in the board file. This option is
997 experimental and only available on a few boards. The device
998 tree is available in the global data as gd->fdt_blob.
1000 U-Boot needs to get its device tree from somewhere. This can
1001 be done using one of the two options below:
1004 If this variable is defined, U-Boot will embed a device tree
1005 binary in its image. This device tree file should be in the
1006 board directory and called <soc>-<board>.dts. The binary file
1007 is then picked up in board_init_f() and made available through
1008 the global data structure as gd->blob.
1011 If this variable is defined, U-Boot will build a device tree
1012 binary. It will be called u-boot.dtb. Architecture-specific
1013 code will locate it at run-time. Generally this works by:
1015 cat u-boot.bin u-boot.dtb >image.bin
1017 and in fact, U-Boot does this for you, creating a file called
1018 u-boot-dtb.bin which is useful in the common case. You can
1019 still use the individual files if you need something more
1024 If this variable is defined, it enables watchdog
1025 support for the SoC. There must be support in the SoC
1026 specific code for a watchdog. For the 8xx and 8260
1027 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1028 register. When supported for a specific SoC is
1029 available, then no further board specific code should
1030 be needed to use it.
1033 When using a watchdog circuitry external to the used
1034 SoC, then define this variable and provide board
1035 specific code for the "hw_watchdog_reset" function.
1038 CONFIG_VERSION_VARIABLE
1039 If this variable is defined, an environment variable
1040 named "ver" is created by U-Boot showing the U-Boot
1041 version as printed by the "version" command.
1042 Any change to this variable will be reverted at the
1047 When CONFIG_CMD_DATE is selected, the type of the RTC
1048 has to be selected, too. Define exactly one of the
1051 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1052 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1053 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1054 CONFIG_RTC_MC146818 - use MC146818 RTC
1055 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1056 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1057 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1058 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1059 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1060 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1061 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1062 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1065 Note that if the RTC uses I2C, then the I2C interface
1066 must also be configured. See I2C Support, below.
1069 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1071 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1072 chip-ngpio pairs that tell the PCA953X driver the number of
1073 pins supported by a particular chip.
1075 Note that if the GPIO device uses I2C, then the I2C interface
1076 must also be configured. See I2C Support, below.
1078 - Timestamp Support:
1080 When CONFIG_TIMESTAMP is selected, the timestamp
1081 (date and time) of an image is printed by image
1082 commands like bootm or iminfo. This option is
1083 automatically enabled when you select CONFIG_CMD_DATE .
1085 - Partition Labels (disklabels) Supported:
1086 Zero or more of the following:
1087 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1088 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1089 Intel architecture, USB sticks, etc.
1090 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1091 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1092 bootloader. Note 2TB partition limit; see
1094 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1096 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1097 CONFIG_CMD_SCSI) you must configure support for at
1098 least one non-MTD partition type as well.
1101 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1102 board configurations files but used nowhere!
1104 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1105 be performed by calling the function
1106 ide_set_reset(int reset)
1107 which has to be defined in a board specific file
1112 Set this to enable ATAPI support.
1117 Set this to enable support for disks larger than 137GB
1118 Also look at CONFIG_SYS_64BIT_LBA.
1119 Whithout these , LBA48 support uses 32bit variables and will 'only'
1120 support disks up to 2.1TB.
1122 CONFIG_SYS_64BIT_LBA:
1123 When enabled, makes the IDE subsystem use 64bit sector addresses.
1127 At the moment only there is only support for the
1128 SYM53C8XX SCSI controller; define
1129 CONFIG_SCSI_SYM53C8XX to enable it.
1131 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1132 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1133 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1134 maximum numbers of LUNs, SCSI ID's and target
1136 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1138 The environment variable 'scsidevs' is set to the number of
1139 SCSI devices found during the last scan.
1141 - NETWORK Support (PCI):
1143 Support for Intel 8254x/8257x gigabit chips.
1146 Utility code for direct access to the SPI bus on Intel 8257x.
1147 This does not do anything useful unless you set at least one
1148 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1150 CONFIG_E1000_SPI_GENERIC
1151 Allow generic access to the SPI bus on the Intel 8257x, for
1152 example with the "sspi" command.
1155 Management command for E1000 devices. When used on devices
1156 with SPI support you can reprogram the EEPROM from U-Boot.
1158 CONFIG_E1000_FALLBACK_MAC
1159 default MAC for empty EEPROM after production.
1162 Support for Intel 82557/82559/82559ER chips.
1163 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1164 write routine for first time initialisation.
1167 Support for Digital 2114x chips.
1168 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1169 modem chip initialisation (KS8761/QS6611).
1172 Support for National dp83815 chips.
1175 Support for National dp8382[01] gigabit chips.
1177 - NETWORK Support (other):
1179 CONFIG_DRIVER_AT91EMAC
1180 Support for AT91RM9200 EMAC.
1183 Define this to use reduced MII inteface
1185 CONFIG_DRIVER_AT91EMAC_QUIET
1186 If this defined, the driver is quiet.
1187 The driver doen't show link status messages.
1189 CONFIG_CALXEDA_XGMAC
1190 Support for the Calxeda XGMAC device
1193 Support for SMSC's LAN91C96 chips.
1195 CONFIG_LAN91C96_BASE
1196 Define this to hold the physical address
1197 of the LAN91C96's I/O space
1199 CONFIG_LAN91C96_USE_32_BIT
1200 Define this to enable 32 bit addressing
1203 Support for SMSC's LAN91C111 chip
1205 CONFIG_SMC91111_BASE
1206 Define this to hold the physical address
1207 of the device (I/O space)
1209 CONFIG_SMC_USE_32_BIT
1210 Define this if data bus is 32 bits
1212 CONFIG_SMC_USE_IOFUNCS
1213 Define this to use i/o functions instead of macros
1214 (some hardware wont work with macros)
1216 CONFIG_DRIVER_TI_EMAC
1217 Support for davinci emac
1219 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1220 Define this if you have more then 3 PHYs.
1223 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1225 CONFIG_FTGMAC100_EGIGA
1226 Define this to use GE link update with gigabit PHY.
1227 Define this if FTGMAC100 is connected to gigabit PHY.
1228 If your system has 10/100 PHY only, it might not occur
1229 wrong behavior. Because PHY usually return timeout or
1230 useless data when polling gigabit status and gigabit
1231 control registers. This behavior won't affect the
1232 correctnessof 10/100 link speed update.
1235 Support for SMSC's LAN911x and LAN921x chips
1238 Define this to hold the physical address
1239 of the device (I/O space)
1241 CONFIG_SMC911X_32_BIT
1242 Define this if data bus is 32 bits
1244 CONFIG_SMC911X_16_BIT
1245 Define this if data bus is 16 bits. If your processor
1246 automatically converts one 32 bit word to two 16 bit
1247 words you may also try CONFIG_SMC911X_32_BIT.
1250 Support for Renesas on-chip Ethernet controller
1252 CONFIG_SH_ETHER_USE_PORT
1253 Define the number of ports to be used
1255 CONFIG_SH_ETHER_PHY_ADDR
1256 Define the ETH PHY's address
1258 CONFIG_SH_ETHER_CACHE_WRITEBACK
1259 If this option is set, the driver enables cache flush.
1263 Support TPM devices.
1266 Support for i2c bus TPM devices. Only one device
1267 per system is supported at this time.
1269 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1270 Define the the i2c bus number for the TPM device
1272 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1273 Define the TPM's address on the i2c bus
1275 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1276 Define the burst count bytes upper limit
1278 CONFIG_TPM_ATMEL_TWI
1279 Support for Atmel TWI TPM device. Requires I2C support.
1282 Support for generic parallel port TPM devices. Only one device
1283 per system is supported at this time.
1285 CONFIG_TPM_TIS_BASE_ADDRESS
1286 Base address where the generic TPM device is mapped
1287 to. Contemporary x86 systems usually map it at
1291 Add tpm monitor functions.
1292 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1293 provides monitor access to authorized functions.
1296 Define this to enable the TPM support library which provides
1297 functional interfaces to some TPM commands.
1298 Requires support for a TPM device.
1300 CONFIG_TPM_AUTH_SESSIONS
1301 Define this to enable authorized functions in the TPM library.
1302 Requires CONFIG_TPM and CONFIG_SHA1.
1305 At the moment only the UHCI host controller is
1306 supported (PIP405, MIP405, MPC5200); define
1307 CONFIG_USB_UHCI to enable it.
1308 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1309 and define CONFIG_USB_STORAGE to enable the USB
1312 Supported are USB Keyboards and USB Floppy drives
1314 MPC5200 USB requires additional defines:
1316 for 528 MHz Clock: 0x0001bbbb
1320 for differential drivers: 0x00001000
1321 for single ended drivers: 0x00005000
1322 for differential drivers on PSC3: 0x00000100
1323 for single ended drivers on PSC3: 0x00004100
1324 CONFIG_SYS_USB_EVENT_POLL
1325 May be defined to allow interrupt polling
1326 instead of using asynchronous interrupts
1328 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1329 txfilltuning field in the EHCI controller on reset.
1331 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1332 interval for usb hub power-on delay.(minimum 100msec)
1335 Define the below if you wish to use the USB console.
1336 Once firmware is rebuilt from a serial console issue the
1337 command "setenv stdin usbtty; setenv stdout usbtty" and
1338 attach your USB cable. The Unix command "dmesg" should print
1339 it has found a new device. The environment variable usbtty
1340 can be set to gserial or cdc_acm to enable your device to
1341 appear to a USB host as a Linux gserial device or a
1342 Common Device Class Abstract Control Model serial device.
1343 If you select usbtty = gserial you should be able to enumerate
1345 # modprobe usbserial vendor=0xVendorID product=0xProductID
1346 else if using cdc_acm, simply setting the environment
1347 variable usbtty to be cdc_acm should suffice. The following
1348 might be defined in YourBoardName.h
1351 Define this to build a UDC device
1354 Define this to have a tty type of device available to
1355 talk to the UDC device
1358 Define this to enable the high speed support for usb
1359 device and usbtty. If this feature is enabled, a routine
1360 int is_usbd_high_speed(void)
1361 also needs to be defined by the driver to dynamically poll
1362 whether the enumeration has succeded at high speed or full
1365 CONFIG_SYS_CONSOLE_IS_IN_ENV
1366 Define this if you want stdin, stdout &/or stderr to
1370 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1371 Derive USB clock from external clock "blah"
1372 - CONFIG_SYS_USB_EXTC_CLK 0x02
1374 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1375 Derive USB clock from brgclk
1376 - CONFIG_SYS_USB_BRG_CLK 0x04
1378 If you have a USB-IF assigned VendorID then you may wish to
1379 define your own vendor specific values either in BoardName.h
1380 or directly in usbd_vendor_info.h. If you don't define
1381 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1382 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1383 should pretend to be a Linux device to it's target host.
1385 CONFIG_USBD_MANUFACTURER
1386 Define this string as the name of your company for
1387 - CONFIG_USBD_MANUFACTURER "my company"
1389 CONFIG_USBD_PRODUCT_NAME
1390 Define this string as the name of your product
1391 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1393 CONFIG_USBD_VENDORID
1394 Define this as your assigned Vendor ID from the USB
1395 Implementors Forum. This *must* be a genuine Vendor ID
1396 to avoid polluting the USB namespace.
1397 - CONFIG_USBD_VENDORID 0xFFFF
1399 CONFIG_USBD_PRODUCTID
1400 Define this as the unique Product ID
1402 - CONFIG_USBD_PRODUCTID 0xFFFF
1404 Some USB device drivers may need to check USB cable attachment.
1405 In this case you can enable following config in BoardName.h:
1406 CONFIG_USB_CABLE_CHECK
1407 This enables function definition:
1408 - usb_cable_connected() in include/usb.h
1409 Implementation of this function is board-specific.
1411 - ULPI Layer Support:
1412 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1413 the generic ULPI layer. The generic layer accesses the ULPI PHY
1414 via the platform viewport, so you need both the genric layer and
1415 the viewport enabled. Currently only Chipidea/ARC based
1416 viewport is supported.
1417 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1418 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1419 If your ULPI phy needs a different reference clock than the
1420 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1421 the appropriate value in Hz.
1424 The MMC controller on the Intel PXA is supported. To
1425 enable this define CONFIG_MMC. The MMC can be
1426 accessed from the boot prompt by mapping the device
1427 to physical memory similar to flash. Command line is
1428 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1429 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1432 Support for Renesas on-chip MMCIF controller
1434 CONFIG_SH_MMCIF_ADDR
1435 Define the base address of MMCIF registers
1438 Define the clock frequency for MMCIF
1440 - USB Device Firmware Update (DFU) class support:
1442 This enables the USB portion of the DFU USB class
1445 This enables the command "dfu" which is used to have
1446 U-Boot create a DFU class device via USB. This command
1447 requires that the "dfu_alt_info" environment variable be
1448 set and define the alt settings to expose to the host.
1451 This enables support for exposing (e)MMC devices via DFU.
1454 This enables support for exposing NAND devices via DFU.
1457 This enables support for exposing RAM via DFU.
1458 Note: DFU spec refer to non-volatile memory usage, but
1459 allow usages beyond the scope of spec - here RAM usage,
1460 one that would help mostly the developer.
1462 CONFIG_SYS_DFU_DATA_BUF_SIZE
1463 Dfu transfer uses a buffer before writing data to the
1464 raw storage device. Make the size (in bytes) of this buffer
1465 configurable. The size of this buffer is also configurable
1466 through the "dfu_bufsiz" environment variable.
1468 CONFIG_SYS_DFU_MAX_FILE_SIZE
1469 When updating files rather than the raw storage device,
1470 we use a static buffer to copy the file into and then write
1471 the buffer once we've been given the whole file. Define
1472 this to the maximum filesize (in bytes) for the buffer.
1473 Default is 4 MiB if undefined.
1475 - Journaling Flash filesystem support:
1476 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1477 CONFIG_JFFS2_NAND_DEV
1478 Define these for a default partition on a NAND device
1480 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1481 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1482 Define these for a default partition on a NOR device
1484 CONFIG_SYS_JFFS_CUSTOM_PART
1485 Define this to create an own partition. You have to provide a
1486 function struct part_info* jffs2_part_info(int part_num)
1488 If you define only one JFFS2 partition you may also want to
1489 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1490 to disable the command chpart. This is the default when you
1491 have not defined a custom partition
1493 - FAT(File Allocation Table) filesystem write function support:
1496 Define this to enable support for saving memory data as a
1497 file in FAT formatted partition.
1499 This will also enable the command "fatwrite" enabling the
1500 user to write files to FAT.
1502 CBFS (Coreboot Filesystem) support
1505 Define this to enable support for reading from a Coreboot
1506 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1512 Define this to enable standard (PC-Style) keyboard
1516 Standard PC keyboard driver with US (is default) and
1517 GERMAN key layout (switch via environment 'keymap=de') support.
1518 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1519 for cfb_console. Supports cursor blinking.
1522 Enables a Chrome OS keyboard using the CROS_EC interface.
1523 This uses CROS_EC to communicate with a second microcontroller
1524 which provides key scans on request.
1529 Define this to enable video support (for output to
1532 CONFIG_VIDEO_CT69000
1534 Enable Chips & Technologies 69000 Video chip
1536 CONFIG_VIDEO_SMI_LYNXEM
1537 Enable Silicon Motion SMI 712/710/810 Video chip. The
1538 video output is selected via environment 'videoout'
1539 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1542 For the CT69000 and SMI_LYNXEM drivers, videomode is
1543 selected via environment 'videomode'. Two different ways
1545 - "videomode=num" 'num' is a standard LiLo mode numbers.
1546 Following standard modes are supported (* is default):
1548 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1549 -------------+---------------------------------------------
1550 8 bits | 0x301* 0x303 0x305 0x161 0x307
1551 15 bits | 0x310 0x313 0x316 0x162 0x319
1552 16 bits | 0x311 0x314 0x317 0x163 0x31A
1553 24 bits | 0x312 0x315 0x318 ? 0x31B
1554 -------------+---------------------------------------------
1555 (i.e. setenv videomode 317; saveenv; reset;)
1557 - "videomode=bootargs" all the video parameters are parsed
1558 from the bootargs. (See drivers/video/videomodes.c)
1561 CONFIG_VIDEO_SED13806
1562 Enable Epson SED13806 driver. This driver supports 8bpp
1563 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1564 or CONFIG_VIDEO_SED13806_16BPP
1567 Enable the Freescale DIU video driver. Reference boards for
1568 SOCs that have a DIU should define this macro to enable DIU
1569 support, and should also define these other macros:
1575 CONFIG_VIDEO_SW_CURSOR
1576 CONFIG_VGA_AS_SINGLE_DEVICE
1578 CONFIG_VIDEO_BMP_LOGO
1580 The DIU driver will look for the 'video-mode' environment
1581 variable, and if defined, enable the DIU as a console during
1582 boot. See the documentation file README.video for a
1583 description of this variable.
1587 Enable the VGA video / BIOS for x86. The alternative if you
1588 are using coreboot is to use the coreboot frame buffer
1595 Define this to enable a custom keyboard support.
1596 This simply calls drv_keyboard_init() which must be
1597 defined in your board-specific files.
1598 The only board using this so far is RBC823.
1600 - LCD Support: CONFIG_LCD
1602 Define this to enable LCD support (for output to LCD
1603 display); also select one of the supported displays
1604 by defining one of these:
1608 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1610 CONFIG_NEC_NL6448AC33:
1612 NEC NL6448AC33-18. Active, color, single scan.
1614 CONFIG_NEC_NL6448BC20
1616 NEC NL6448BC20-08. 6.5", 640x480.
1617 Active, color, single scan.
1619 CONFIG_NEC_NL6448BC33_54
1621 NEC NL6448BC33-54. 10.4", 640x480.
1622 Active, color, single scan.
1626 Sharp 320x240. Active, color, single scan.
1627 It isn't 16x9, and I am not sure what it is.
1629 CONFIG_SHARP_LQ64D341
1631 Sharp LQ64D341 display, 640x480.
1632 Active, color, single scan.
1636 HLD1045 display, 640x480.
1637 Active, color, single scan.
1641 Optrex CBL50840-2 NF-FW 99 22 M5
1643 Hitachi LMG6912RPFC-00T
1647 320x240. Black & white.
1649 Normally display is black on white background; define
1650 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1652 CONFIG_LCD_ALIGNMENT
1654 Normally the LCD is page-aligned (tyically 4KB). If this is
1655 defined then the LCD will be aligned to this value instead.
1656 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1657 here, since it is cheaper to change data cache settings on
1658 a per-section basis.
1660 CONFIG_CONSOLE_SCROLL_LINES
1662 When the console need to be scrolled, this is the number of
1663 lines to scroll by. It defaults to 1. Increasing this makes
1664 the console jump but can help speed up operation when scrolling
1669 Support drawing of RLE8-compressed bitmaps on the LCD.
1673 Enables an 'i2c edid' command which can read EDID
1674 information over I2C from an attached LCD display.
1676 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1678 If this option is set, the environment is checked for
1679 a variable "splashimage". If found, the usual display
1680 of logo, copyright and system information on the LCD
1681 is suppressed and the BMP image at the address
1682 specified in "splashimage" is loaded instead. The
1683 console is redirected to the "nulldev", too. This
1684 allows for a "silent" boot where a splash screen is
1685 loaded very quickly after power-on.
1687 CONFIG_SPLASHIMAGE_GUARD
1689 If this option is set, then U-Boot will prevent the environment
1690 variable "splashimage" from being set to a problematic address
1691 (see README.displaying-bmps and README.arm-unaligned-accesses).
1692 This option is useful for targets where, due to alignment
1693 restrictions, an improperly aligned BMP image will cause a data
1694 abort. If you think you will not have problems with unaligned
1695 accesses (for example because your toolchain prevents them)
1696 there is no need to set this option.
1698 CONFIG_SPLASH_SCREEN_ALIGN
1700 If this option is set the splash image can be freely positioned
1701 on the screen. Environment variable "splashpos" specifies the
1702 position as "x,y". If a positive number is given it is used as
1703 number of pixel from left/top. If a negative number is given it
1704 is used as number of pixel from right/bottom. You can also
1705 specify 'm' for centering the image.
1708 setenv splashpos m,m
1709 => image at center of screen
1711 setenv splashpos 30,20
1712 => image at x = 30 and y = 20
1714 setenv splashpos -10,m
1715 => vertically centered image
1716 at x = dspWidth - bmpWidth - 9
1718 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1720 If this option is set, additionally to standard BMP
1721 images, gzipped BMP images can be displayed via the
1722 splashscreen support or the bmp command.
1724 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1726 If this option is set, 8-bit RLE compressed BMP images
1727 can be displayed via the splashscreen support or the
1730 - Do compresssing for memory range:
1733 If this option is set, it would use zlib deflate method
1734 to compress the specified memory at its best effort.
1736 - Compression support:
1739 Enabled by default to support gzip compressed images.
1743 If this option is set, support for bzip2 compressed
1744 images is included. If not, only uncompressed and gzip
1745 compressed images are supported.
1747 NOTE: the bzip2 algorithm requires a lot of RAM, so
1748 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1753 If this option is set, support for lzma compressed
1756 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1757 requires an amount of dynamic memory that is given by the
1760 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1762 Where lc and lp stand for, respectively, Literal context bits
1763 and Literal pos bits.
1765 This value is upper-bounded by 14MB in the worst case. Anyway,
1766 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1767 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1768 a very small buffer.
1770 Use the lzmainfo tool to determinate the lc and lp values and
1771 then calculate the amount of needed dynamic memory (ensuring
1772 the appropriate CONFIG_SYS_MALLOC_LEN value).
1776 If this option is set, support for LZO compressed images
1782 The address of PHY on MII bus.
1784 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1786 The clock frequency of the MII bus
1790 If this option is set, support for speed/duplex
1791 detection of gigabit PHY is included.
1793 CONFIG_PHY_RESET_DELAY
1795 Some PHY like Intel LXT971A need extra delay after
1796 reset before any MII register access is possible.
1797 For such PHY, set this option to the usec delay
1798 required. (minimum 300usec for LXT971A)
1800 CONFIG_PHY_CMD_DELAY (ppc4xx)
1802 Some PHY like Intel LXT971A need extra delay after
1803 command issued before MII status register can be read
1813 Define a default value for Ethernet address to use
1814 for the respective Ethernet interface, in case this
1815 is not determined automatically.
1820 Define a default value for the IP address to use for
1821 the default Ethernet interface, in case this is not
1822 determined through e.g. bootp.
1823 (Environment variable "ipaddr")
1825 - Server IP address:
1828 Defines a default value for the IP address of a TFTP
1829 server to contact when using the "tftboot" command.
1830 (Environment variable "serverip")
1832 CONFIG_KEEP_SERVERADDR
1834 Keeps the server's MAC address, in the env 'serveraddr'
1835 for passing to bootargs (like Linux's netconsole option)
1837 - Gateway IP address:
1840 Defines a default value for the IP address of the
1841 default router where packets to other networks are
1843 (Environment variable "gatewayip")
1848 Defines a default value for the subnet mask (or
1849 routing prefix) which is used to determine if an IP
1850 address belongs to the local subnet or needs to be
1851 forwarded through a router.
1852 (Environment variable "netmask")
1854 - Multicast TFTP Mode:
1857 Defines whether you want to support multicast TFTP as per
1858 rfc-2090; for example to work with atftp. Lets lots of targets
1859 tftp down the same boot image concurrently. Note: the Ethernet
1860 driver in use must provide a function: mcast() to join/leave a
1863 - BOOTP Recovery Mode:
1864 CONFIG_BOOTP_RANDOM_DELAY
1866 If you have many targets in a network that try to
1867 boot using BOOTP, you may want to avoid that all
1868 systems send out BOOTP requests at precisely the same
1869 moment (which would happen for instance at recovery
1870 from a power failure, when all systems will try to
1871 boot, thus flooding the BOOTP server. Defining
1872 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1873 inserted before sending out BOOTP requests. The
1874 following delays are inserted then:
1876 1st BOOTP request: delay 0 ... 1 sec
1877 2nd BOOTP request: delay 0 ... 2 sec
1878 3rd BOOTP request: delay 0 ... 4 sec
1880 BOOTP requests: delay 0 ... 8 sec
1882 - DHCP Advanced Options:
1883 You can fine tune the DHCP functionality by defining
1884 CONFIG_BOOTP_* symbols:
1886 CONFIG_BOOTP_SUBNETMASK
1887 CONFIG_BOOTP_GATEWAY
1888 CONFIG_BOOTP_HOSTNAME
1889 CONFIG_BOOTP_NISDOMAIN
1890 CONFIG_BOOTP_BOOTPATH
1891 CONFIG_BOOTP_BOOTFILESIZE
1894 CONFIG_BOOTP_SEND_HOSTNAME
1895 CONFIG_BOOTP_NTPSERVER
1896 CONFIG_BOOTP_TIMEOFFSET
1897 CONFIG_BOOTP_VENDOREX
1898 CONFIG_BOOTP_MAY_FAIL
1900 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1901 environment variable, not the BOOTP server.
1903 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1904 after the configured retry count, the call will fail
1905 instead of starting over. This can be used to fail over
1906 to Link-local IP address configuration if the DHCP server
1909 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1910 serverip from a DHCP server, it is possible that more
1911 than one DNS serverip is offered to the client.
1912 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1913 serverip will be stored in the additional environment
1914 variable "dnsip2". The first DNS serverip is always
1915 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1918 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1919 to do a dynamic update of a DNS server. To do this, they
1920 need the hostname of the DHCP requester.
1921 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1922 of the "hostname" environment variable is passed as
1923 option 12 to the DHCP server.
1925 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1927 A 32bit value in microseconds for a delay between
1928 receiving a "DHCP Offer" and sending the "DHCP Request".
1929 This fixes a problem with certain DHCP servers that don't
1930 respond 100% of the time to a "DHCP request". E.g. On an
1931 AT91RM9200 processor running at 180MHz, this delay needed
1932 to be *at least* 15,000 usec before a Windows Server 2003
1933 DHCP server would reply 100% of the time. I recommend at
1934 least 50,000 usec to be safe. The alternative is to hope
1935 that one of the retries will be successful but note that
1936 the DHCP timeout and retry process takes a longer than
1939 - Link-local IP address negotiation:
1940 Negotiate with other link-local clients on the local network
1941 for an address that doesn't require explicit configuration.
1942 This is especially useful if a DHCP server cannot be guaranteed
1943 to exist in all environments that the device must operate.
1945 See doc/README.link-local for more information.
1948 CONFIG_CDP_DEVICE_ID
1950 The device id used in CDP trigger frames.
1952 CONFIG_CDP_DEVICE_ID_PREFIX
1954 A two character string which is prefixed to the MAC address
1959 A printf format string which contains the ascii name of
1960 the port. Normally is set to "eth%d" which sets
1961 eth0 for the first Ethernet, eth1 for the second etc.
1963 CONFIG_CDP_CAPABILITIES
1965 A 32bit integer which indicates the device capabilities;
1966 0x00000010 for a normal host which does not forwards.
1970 An ascii string containing the version of the software.
1974 An ascii string containing the name of the platform.
1978 A 32bit integer sent on the trigger.
1980 CONFIG_CDP_POWER_CONSUMPTION
1982 A 16bit integer containing the power consumption of the
1983 device in .1 of milliwatts.
1985 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1987 A byte containing the id of the VLAN.
1989 - Status LED: CONFIG_STATUS_LED
1991 Several configurations allow to display the current
1992 status using a LED. For instance, the LED will blink
1993 fast while running U-Boot code, stop blinking as
1994 soon as a reply to a BOOTP request was received, and
1995 start blinking slow once the Linux kernel is running
1996 (supported by a status LED driver in the Linux
1997 kernel). Defining CONFIG_STATUS_LED enables this
2003 The status LED can be connected to a GPIO pin.
2004 In such cases, the gpio_led driver can be used as a
2005 status LED backend implementation. Define CONFIG_GPIO_LED
2006 to include the gpio_led driver in the U-Boot binary.
2008 CONFIG_GPIO_LED_INVERTED_TABLE
2009 Some GPIO connected LEDs may have inverted polarity in which
2010 case the GPIO high value corresponds to LED off state and
2011 GPIO low value corresponds to LED on state.
2012 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2013 with a list of GPIO LEDs that have inverted polarity.
2015 - CAN Support: CONFIG_CAN_DRIVER
2017 Defining CONFIG_CAN_DRIVER enables CAN driver support
2018 on those systems that support this (optional)
2019 feature, like the TQM8xxL modules.
2021 - I2C Support: CONFIG_SYS_I2C
2023 This enable the NEW i2c subsystem, and will allow you to use
2024 i2c commands at the u-boot command line (as long as you set
2025 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2026 based realtime clock chips or other i2c devices. See
2027 common/cmd_i2c.c for a description of the command line
2030 ported i2c driver to the new framework:
2031 - drivers/i2c/soft_i2c.c:
2032 - activate first bus with CONFIG_SYS_I2C_SOFT define
2033 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2034 for defining speed and slave address
2035 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2036 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2037 for defining speed and slave address
2038 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2039 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2040 for defining speed and slave address
2041 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2042 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2043 for defining speed and slave address
2045 - drivers/i2c/fsl_i2c.c:
2046 - activate i2c driver with CONFIG_SYS_I2C_FSL
2047 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2048 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2049 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2051 - If your board supports a second fsl i2c bus, define
2052 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2053 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2054 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2057 - drivers/i2c/tegra_i2c.c:
2058 - activate this driver with CONFIG_SYS_I2C_TEGRA
2059 - This driver adds 4 i2c buses with a fix speed from
2060 100000 and the slave addr 0!
2062 - drivers/i2c/ppc4xx_i2c.c
2063 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2064 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2065 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2067 - drivers/i2c/i2c_mxc.c
2068 - activate this driver with CONFIG_SYS_I2C_MXC
2069 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2070 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2071 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2072 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2073 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2074 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2075 If thoses defines are not set, default value is 100000
2076 for speed, and 0 for slave.
2078 - drivers/i2c/rcar_i2c.c:
2079 - activate this driver with CONFIG_SYS_I2C_RCAR
2080 - This driver adds 4 i2c buses
2082 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2083 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2084 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2085 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2086 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2087 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2088 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2089 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2090 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2092 - drivers/i2c/sh_i2c.c:
2093 - activate this driver with CONFIG_SYS_I2C_SH
2094 - This driver adds from 2 to 5 i2c buses
2096 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2097 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2098 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2099 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2100 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2101 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2102 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2103 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2104 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2105 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2106 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2107 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2108 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2110 - drivers/i2c/omap24xx_i2c.c
2111 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2112 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2113 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2114 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2115 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2116 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2117 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2118 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2119 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2120 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2121 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2123 - drivers/i2c/zynq_i2c.c
2124 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2125 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2126 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2128 - drivers/i2c/s3c24x0_i2c.c:
2129 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2130 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2131 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2132 with a fix speed from 100000 and the slave addr 0!
2136 CONFIG_SYS_NUM_I2C_BUSES
2137 Hold the number of i2c busses you want to use. If you
2138 don't use/have i2c muxes on your i2c bus, this
2139 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2142 CONFIG_SYS_I2C_DIRECT_BUS
2143 define this, if you don't use i2c muxes on your hardware.
2144 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2147 CONFIG_SYS_I2C_MAX_HOPS
2148 define how many muxes are maximal consecutively connected
2149 on one i2c bus. If you not use i2c muxes, omit this
2152 CONFIG_SYS_I2C_BUSES
2153 hold a list of busses you want to use, only used if
2154 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2155 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2156 CONFIG_SYS_NUM_I2C_BUSES = 9:
2158 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2159 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2160 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2161 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2162 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2163 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2164 {1, {I2C_NULL_HOP}}, \
2165 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2166 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2170 bus 0 on adapter 0 without a mux
2171 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2172 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2173 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2174 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2175 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2176 bus 6 on adapter 1 without a mux
2177 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2178 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2180 If you do not have i2c muxes on your board, omit this define.
2182 - Legacy I2C Support: CONFIG_HARD_I2C
2184 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2185 provides the following compelling advantages:
2187 - more than one i2c adapter is usable
2188 - approved multibus support
2189 - better i2c mux support
2191 ** Please consider updating your I2C driver now. **
2193 These enable legacy I2C serial bus commands. Defining
2194 CONFIG_HARD_I2C will include the appropriate I2C driver
2195 for the selected CPU.
2197 This will allow you to use i2c commands at the u-boot
2198 command line (as long as you set CONFIG_CMD_I2C in
2199 CONFIG_COMMANDS) and communicate with i2c based realtime
2200 clock chips. See common/cmd_i2c.c for a description of the
2201 command line interface.
2203 CONFIG_HARD_I2C selects a hardware I2C controller.
2205 There are several other quantities that must also be
2206 defined when you define CONFIG_HARD_I2C.
2208 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2209 to be the frequency (in Hz) at which you wish your i2c bus
2210 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2211 the CPU's i2c node address).
2213 Now, the u-boot i2c code for the mpc8xx
2214 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2215 and so its address should therefore be cleared to 0 (See,
2216 eg, MPC823e User's Manual p.16-473). So, set
2217 CONFIG_SYS_I2C_SLAVE to 0.
2219 CONFIG_SYS_I2C_INIT_MPC5XXX
2221 When a board is reset during an i2c bus transfer
2222 chips might think that the current transfer is still
2223 in progress. Reset the slave devices by sending start
2224 commands until the slave device responds.
2226 That's all that's required for CONFIG_HARD_I2C.
2228 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2229 then the following macros need to be defined (examples are
2230 from include/configs/lwmon.h):
2234 (Optional). Any commands necessary to enable the I2C
2235 controller or configure ports.
2237 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2241 (Only for MPC8260 CPU). The I/O port to use (the code
2242 assumes both bits are on the same port). Valid values
2243 are 0..3 for ports A..D.
2247 The code necessary to make the I2C data line active
2248 (driven). If the data line is open collector, this
2251 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2255 The code necessary to make the I2C data line tri-stated
2256 (inactive). If the data line is open collector, this
2259 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2263 Code that returns true if the I2C data line is high,
2266 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2270 If <bit> is true, sets the I2C data line high. If it
2271 is false, it clears it (low).
2273 eg: #define I2C_SDA(bit) \
2274 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2275 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2279 If <bit> is true, sets the I2C clock line high. If it
2280 is false, it clears it (low).
2282 eg: #define I2C_SCL(bit) \
2283 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2284 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2288 This delay is invoked four times per clock cycle so this
2289 controls the rate of data transfer. The data rate thus
2290 is 1 / (I2C_DELAY * 4). Often defined to be something
2293 #define I2C_DELAY udelay(2)
2295 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2297 If your arch supports the generic GPIO framework (asm/gpio.h),
2298 then you may alternatively define the two GPIOs that are to be
2299 used as SCL / SDA. Any of the previous I2C_xxx macros will
2300 have GPIO-based defaults assigned to them as appropriate.
2302 You should define these to the GPIO value as given directly to
2303 the generic GPIO functions.
2305 CONFIG_SYS_I2C_INIT_BOARD
2307 When a board is reset during an i2c bus transfer
2308 chips might think that the current transfer is still
2309 in progress. On some boards it is possible to access
2310 the i2c SCLK line directly, either by using the
2311 processor pin as a GPIO or by having a second pin
2312 connected to the bus. If this option is defined a
2313 custom i2c_init_board() routine in boards/xxx/board.c
2314 is run early in the boot sequence.
2316 CONFIG_SYS_I2C_BOARD_LATE_INIT
2318 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2319 defined a custom i2c_board_late_init() routine in
2320 boards/xxx/board.c is run AFTER the operations in i2c_init()
2321 is completed. This callpoint can be used to unreset i2c bus
2322 using CPU i2c controller register accesses for CPUs whose i2c
2323 controller provide such a method. It is called at the end of
2324 i2c_init() to allow i2c_init operations to setup the i2c bus
2325 controller on the CPU (e.g. setting bus speed & slave address).
2327 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2329 This option enables configuration of bi_iic_fast[] flags
2330 in u-boot bd_info structure based on u-boot environment
2331 variable "i2cfast". (see also i2cfast)
2333 CONFIG_I2C_MULTI_BUS
2335 This option allows the use of multiple I2C buses, each of which
2336 must have a controller. At any point in time, only one bus is
2337 active. To switch to a different bus, use the 'i2c dev' command.
2338 Note that bus numbering is zero-based.
2340 CONFIG_SYS_I2C_NOPROBES
2342 This option specifies a list of I2C devices that will be skipped
2343 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2344 is set, specify a list of bus-device pairs. Otherwise, specify
2345 a 1D array of device addresses
2348 #undef CONFIG_I2C_MULTI_BUS
2349 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2351 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2353 #define CONFIG_I2C_MULTI_BUS
2354 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2356 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2358 CONFIG_SYS_SPD_BUS_NUM
2360 If defined, then this indicates the I2C bus number for DDR SPD.
2361 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2363 CONFIG_SYS_RTC_BUS_NUM
2365 If defined, then this indicates the I2C bus number for the RTC.
2366 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2368 CONFIG_SYS_DTT_BUS_NUM
2370 If defined, then this indicates the I2C bus number for the DTT.
2371 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2373 CONFIG_SYS_I2C_DTT_ADDR:
2375 If defined, specifies the I2C address of the DTT device.
2376 If not defined, then U-Boot uses predefined value for
2377 specified DTT device.
2379 CONFIG_SOFT_I2C_READ_REPEATED_START
2381 defining this will force the i2c_read() function in
2382 the soft_i2c driver to perform an I2C repeated start
2383 between writing the address pointer and reading the
2384 data. If this define is omitted the default behaviour
2385 of doing a stop-start sequence will be used. Most I2C
2386 devices can use either method, but some require one or
2389 - SPI Support: CONFIG_SPI
2391 Enables SPI driver (so far only tested with
2392 SPI EEPROM, also an instance works with Crystal A/D and
2393 D/As on the SACSng board)
2397 Enables the driver for SPI controller on SuperH. Currently
2398 only SH7757 is supported.
2402 Enables extended (16-bit) SPI EEPROM addressing.
2403 (symmetrical to CONFIG_I2C_X)
2407 Enables a software (bit-bang) SPI driver rather than
2408 using hardware support. This is a general purpose
2409 driver that only requires three general I/O port pins
2410 (two outputs, one input) to function. If this is
2411 defined, the board configuration must define several
2412 SPI configuration items (port pins to use, etc). For
2413 an example, see include/configs/sacsng.h.
2417 Enables a hardware SPI driver for general-purpose reads
2418 and writes. As with CONFIG_SOFT_SPI, the board configuration
2419 must define a list of chip-select function pointers.
2420 Currently supported on some MPC8xxx processors. For an
2421 example, see include/configs/mpc8349emds.h.
2425 Enables the driver for the SPI controllers on i.MX and MXC
2426 SoCs. Currently i.MX31/35/51 are supported.
2428 - FPGA Support: CONFIG_FPGA
2430 Enables FPGA subsystem.
2432 CONFIG_FPGA_<vendor>
2434 Enables support for specific chip vendors.
2437 CONFIG_FPGA_<family>
2439 Enables support for FPGA family.
2440 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2444 Specify the number of FPGA devices to support.
2446 CONFIG_SYS_FPGA_PROG_FEEDBACK
2448 Enable printing of hash marks during FPGA configuration.
2450 CONFIG_SYS_FPGA_CHECK_BUSY
2452 Enable checks on FPGA configuration interface busy
2453 status by the configuration function. This option
2454 will require a board or device specific function to
2459 If defined, a function that provides delays in the FPGA
2460 configuration driver.
2462 CONFIG_SYS_FPGA_CHECK_CTRLC
2463 Allow Control-C to interrupt FPGA configuration
2465 CONFIG_SYS_FPGA_CHECK_ERROR
2467 Check for configuration errors during FPGA bitfile
2468 loading. For example, abort during Virtex II
2469 configuration if the INIT_B line goes low (which
2470 indicated a CRC error).
2472 CONFIG_SYS_FPGA_WAIT_INIT
2474 Maximum time to wait for the INIT_B line to deassert
2475 after PROB_B has been deasserted during a Virtex II
2476 FPGA configuration sequence. The default time is 500
2479 CONFIG_SYS_FPGA_WAIT_BUSY
2481 Maximum time to wait for BUSY to deassert during
2482 Virtex II FPGA configuration. The default is 5 ms.
2484 CONFIG_SYS_FPGA_WAIT_CONFIG
2486 Time to wait after FPGA configuration. The default is
2489 - Configuration Management:
2492 If defined, this string will be added to the U-Boot
2493 version information (U_BOOT_VERSION)
2495 - Vendor Parameter Protection:
2497 U-Boot considers the values of the environment
2498 variables "serial#" (Board Serial Number) and
2499 "ethaddr" (Ethernet Address) to be parameters that
2500 are set once by the board vendor / manufacturer, and
2501 protects these variables from casual modification by
2502 the user. Once set, these variables are read-only,
2503 and write or delete attempts are rejected. You can
2504 change this behaviour:
2506 If CONFIG_ENV_OVERWRITE is #defined in your config
2507 file, the write protection for vendor parameters is
2508 completely disabled. Anybody can change or delete
2511 Alternatively, if you #define _both_ CONFIG_ETHADDR
2512 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2513 Ethernet address is installed in the environment,
2514 which can be changed exactly ONCE by the user. [The
2515 serial# is unaffected by this, i. e. it remains
2518 The same can be accomplished in a more flexible way
2519 for any variable by configuring the type of access
2520 to allow for those variables in the ".flags" variable
2521 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2526 Define this variable to enable the reservation of
2527 "protected RAM", i. e. RAM which is not overwritten
2528 by U-Boot. Define CONFIG_PRAM to hold the number of
2529 kB you want to reserve for pRAM. You can overwrite
2530 this default value by defining an environment
2531 variable "pram" to the number of kB you want to
2532 reserve. Note that the board info structure will
2533 still show the full amount of RAM. If pRAM is
2534 reserved, a new environment variable "mem" will
2535 automatically be defined to hold the amount of
2536 remaining RAM in a form that can be passed as boot
2537 argument to Linux, for instance like that:
2539 setenv bootargs ... mem=\${mem}
2542 This way you can tell Linux not to use this memory,
2543 either, which results in a memory region that will
2544 not be affected by reboots.
2546 *WARNING* If your board configuration uses automatic
2547 detection of the RAM size, you must make sure that
2548 this memory test is non-destructive. So far, the
2549 following board configurations are known to be
2552 IVMS8, IVML24, SPD8xx, TQM8xxL,
2553 HERMES, IP860, RPXlite, LWMON,
2556 - Access to physical memory region (> 4GB)
2557 Some basic support is provided for operations on memory not
2558 normally accessible to U-Boot - e.g. some architectures
2559 support access to more than 4GB of memory on 32-bit
2560 machines using physical address extension or similar.
2561 Define CONFIG_PHYSMEM to access this basic support, which
2562 currently only supports clearing the memory.
2567 Define this variable to stop the system in case of a
2568 fatal error, so that you have to reset it manually.
2569 This is probably NOT a good idea for an embedded
2570 system where you want the system to reboot
2571 automatically as fast as possible, but it may be
2572 useful during development since you can try to debug
2573 the conditions that lead to the situation.
2575 CONFIG_NET_RETRY_COUNT
2577 This variable defines the number of retries for
2578 network operations like ARP, RARP, TFTP, or BOOTP
2579 before giving up the operation. If not defined, a
2580 default value of 5 is used.
2584 Timeout waiting for an ARP reply in milliseconds.
2588 Timeout in milliseconds used in NFS protocol.
2589 If you encounter "ERROR: Cannot umount" in nfs command,
2590 try longer timeout such as
2591 #define CONFIG_NFS_TIMEOUT 10000UL
2593 - Command Interpreter:
2594 CONFIG_AUTO_COMPLETE
2596 Enable auto completion of commands using TAB.
2598 Note that this feature has NOT been implemented yet
2599 for the "hush" shell.
2602 CONFIG_SYS_HUSH_PARSER
2604 Define this variable to enable the "hush" shell (from
2605 Busybox) as command line interpreter, thus enabling
2606 powerful command line syntax like
2607 if...then...else...fi conditionals or `&&' and '||'
2608 constructs ("shell scripts").
2610 If undefined, you get the old, much simpler behaviour
2611 with a somewhat smaller memory footprint.
2614 CONFIG_SYS_PROMPT_HUSH_PS2
2616 This defines the secondary prompt string, which is
2617 printed when the command interpreter needs more input
2618 to complete a command. Usually "> ".
2622 In the current implementation, the local variables
2623 space and global environment variables space are
2624 separated. Local variables are those you define by
2625 simply typing `name=value'. To access a local
2626 variable later on, you have write `$name' or
2627 `${name}'; to execute the contents of a variable
2628 directly type `$name' at the command prompt.
2630 Global environment variables are those you use
2631 setenv/printenv to work with. To run a command stored
2632 in such a variable, you need to use the run command,
2633 and you must not use the '$' sign to access them.
2635 To store commands and special characters in a
2636 variable, please use double quotation marks
2637 surrounding the whole text of the variable, instead
2638 of the backslashes before semicolons and special
2641 - Commandline Editing and History:
2642 CONFIG_CMDLINE_EDITING
2644 Enable editing and History functions for interactive
2645 commandline input operations
2647 - Default Environment:
2648 CONFIG_EXTRA_ENV_SETTINGS
2650 Define this to contain any number of null terminated
2651 strings (variable = value pairs) that will be part of
2652 the default environment compiled into the boot image.
2654 For example, place something like this in your
2655 board's config file:
2657 #define CONFIG_EXTRA_ENV_SETTINGS \
2661 Warning: This method is based on knowledge about the
2662 internal format how the environment is stored by the
2663 U-Boot code. This is NOT an official, exported
2664 interface! Although it is unlikely that this format
2665 will change soon, there is no guarantee either.
2666 You better know what you are doing here.
2668 Note: overly (ab)use of the default environment is
2669 discouraged. Make sure to check other ways to preset
2670 the environment like the "source" command or the
2673 CONFIG_ENV_VARS_UBOOT_CONFIG
2675 Define this in order to add variables describing the
2676 U-Boot build configuration to the default environment.
2677 These will be named arch, cpu, board, vendor, and soc.
2679 Enabling this option will cause the following to be defined:
2687 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2689 Define this in order to add variables describing certain
2690 run-time determined information about the hardware to the
2691 environment. These will be named board_name, board_rev.
2693 CONFIG_DELAY_ENVIRONMENT
2695 Normally the environment is loaded when the board is
2696 intialised so that it is available to U-Boot. This inhibits
2697 that so that the environment is not available until
2698 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2699 this is instead controlled by the value of
2700 /config/load-environment.
2702 - DataFlash Support:
2703 CONFIG_HAS_DATAFLASH
2705 Defining this option enables DataFlash features and
2706 allows to read/write in Dataflash via the standard
2709 - Serial Flash support
2712 Defining this option enables SPI flash commands
2713 'sf probe/read/write/erase/update'.
2715 Usage requires an initial 'probe' to define the serial
2716 flash parameters, followed by read/write/erase/update
2719 The following defaults may be provided by the platform
2720 to handle the common case when only a single serial
2721 flash is present on the system.
2723 CONFIG_SF_DEFAULT_BUS Bus identifier
2724 CONFIG_SF_DEFAULT_CS Chip-select
2725 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2726 CONFIG_SF_DEFAULT_SPEED in Hz
2730 Define this option to include a destructive SPI flash
2733 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2735 Define this option to use the Bank addr/Extended addr
2736 support on SPI flashes which has size > 16Mbytes.
2738 - SystemACE Support:
2741 Adding this option adds support for Xilinx SystemACE
2742 chips attached via some sort of local bus. The address
2743 of the chip must also be defined in the
2744 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2746 #define CONFIG_SYSTEMACE
2747 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2749 When SystemACE support is added, the "ace" device type
2750 becomes available to the fat commands, i.e. fatls.
2752 - TFTP Fixed UDP Port:
2755 If this is defined, the environment variable tftpsrcp
2756 is used to supply the TFTP UDP source port value.
2757 If tftpsrcp isn't defined, the normal pseudo-random port
2758 number generator is used.
2760 Also, the environment variable tftpdstp is used to supply
2761 the TFTP UDP destination port value. If tftpdstp isn't
2762 defined, the normal port 69 is used.
2764 The purpose for tftpsrcp is to allow a TFTP server to
2765 blindly start the TFTP transfer using the pre-configured
2766 target IP address and UDP port. This has the effect of
2767 "punching through" the (Windows XP) firewall, allowing
2768 the remainder of the TFTP transfer to proceed normally.
2769 A better solution is to properly configure the firewall,
2770 but sometimes that is not allowed.
2775 This enables a generic 'hash' command which can produce
2776 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2780 Enable the hash verify command (hash -v). This adds to code
2783 CONFIG_SHA1 - support SHA1 hashing
2784 CONFIG_SHA256 - support SHA256 hashing
2786 Note: There is also a sha1sum command, which should perhaps
2787 be deprecated in favour of 'hash sha1'.
2789 - Freescale i.MX specific commands:
2790 CONFIG_CMD_HDMIDETECT
2791 This enables 'hdmidet' command which returns true if an
2792 HDMI monitor is detected. This command is i.MX 6 specific.
2795 This enables the 'bmode' (bootmode) command for forcing
2796 a boot from specific media.
2798 This is useful for forcing the ROM's usb downloader to
2799 activate upon a watchdog reset which is nice when iterating
2800 on U-Boot. Using the reset button or running bmode normal
2801 will set it back to normal. This command currently
2802 supports i.MX53 and i.MX6.
2807 This enables the RSA algorithm used for FIT image verification
2808 in U-Boot. See doc/uImage/signature for more information.
2810 The signing part is build into mkimage regardless of this
2814 - Show boot progress:
2815 CONFIG_SHOW_BOOT_PROGRESS
2817 Defining this option allows to add some board-
2818 specific code (calling a user-provided function
2819 "show_boot_progress(int)") that enables you to show
2820 the system's boot progress on some display (for
2821 example, some LED's) on your board. At the moment,
2822 the following checkpoints are implemented:
2824 - Detailed boot stage timing
2826 Define this option to get detailed timing of each stage
2827 of the boot process.
2829 CONFIG_BOOTSTAGE_USER_COUNT
2830 This is the number of available user bootstage records.
2831 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2832 a new ID will be allocated from this stash. If you exceed
2833 the limit, recording will stop.
2835 CONFIG_BOOTSTAGE_REPORT
2836 Define this to print a report before boot, similar to this:
2838 Timer summary in microseconds:
2841 3,575,678 3,575,678 board_init_f start
2842 3,575,695 17 arch_cpu_init A9
2843 3,575,777 82 arch_cpu_init done
2844 3,659,598 83,821 board_init_r start
2845 3,910,375 250,777 main_loop
2846 29,916,167 26,005,792 bootm_start
2847 30,361,327 445,160 start_kernel
2849 CONFIG_CMD_BOOTSTAGE
2850 Add a 'bootstage' command which supports printing a report
2851 and un/stashing of bootstage data.
2853 CONFIG_BOOTSTAGE_FDT
2854 Stash the bootstage information in the FDT. A root 'bootstage'
2855 node is created with each bootstage id as a child. Each child
2856 has a 'name' property and either 'mark' containing the
2857 mark time in microsecond, or 'accum' containing the
2858 accumulated time for that bootstage id in microseconds.
2863 name = "board_init_f";
2872 Code in the Linux kernel can find this in /proc/devicetree.
2874 Legacy uImage format:
2877 1 common/cmd_bootm.c before attempting to boot an image
2878 -1 common/cmd_bootm.c Image header has bad magic number
2879 2 common/cmd_bootm.c Image header has correct magic number
2880 -2 common/cmd_bootm.c Image header has bad checksum
2881 3 common/cmd_bootm.c Image header has correct checksum
2882 -3 common/cmd_bootm.c Image data has bad checksum
2883 4 common/cmd_bootm.c Image data has correct checksum
2884 -4 common/cmd_bootm.c Image is for unsupported architecture
2885 5 common/cmd_bootm.c Architecture check OK
2886 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2887 6 common/cmd_bootm.c Image Type check OK
2888 -6 common/cmd_bootm.c gunzip uncompression error
2889 -7 common/cmd_bootm.c Unimplemented compression type
2890 7 common/cmd_bootm.c Uncompression OK
2891 8 common/cmd_bootm.c No uncompress/copy overwrite error
2892 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2894 9 common/image.c Start initial ramdisk verification
2895 -10 common/image.c Ramdisk header has bad magic number
2896 -11 common/image.c Ramdisk header has bad checksum
2897 10 common/image.c Ramdisk header is OK
2898 -12 common/image.c Ramdisk data has bad checksum
2899 11 common/image.c Ramdisk data has correct checksum
2900 12 common/image.c Ramdisk verification complete, start loading
2901 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2902 13 common/image.c Start multifile image verification
2903 14 common/image.c No initial ramdisk, no multifile, continue.
2905 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2907 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2908 -31 post/post.c POST test failed, detected by post_output_backlog()
2909 -32 post/post.c POST test failed, detected by post_run_single()
2911 34 common/cmd_doc.c before loading a Image from a DOC device
2912 -35 common/cmd_doc.c Bad usage of "doc" command
2913 35 common/cmd_doc.c correct usage of "doc" command
2914 -36 common/cmd_doc.c No boot device
2915 36 common/cmd_doc.c correct boot device
2916 -37 common/cmd_doc.c Unknown Chip ID on boot device
2917 37 common/cmd_doc.c correct chip ID found, device available
2918 -38 common/cmd_doc.c Read Error on boot device
2919 38 common/cmd_doc.c reading Image header from DOC device OK
2920 -39 common/cmd_doc.c Image header has bad magic number
2921 39 common/cmd_doc.c Image header has correct magic number
2922 -40 common/cmd_doc.c Error reading Image from DOC device
2923 40 common/cmd_doc.c Image header has correct magic number
2924 41 common/cmd_ide.c before loading a Image from a IDE device
2925 -42 common/cmd_ide.c Bad usage of "ide" command
2926 42 common/cmd_ide.c correct usage of "ide" command
2927 -43 common/cmd_ide.c No boot device
2928 43 common/cmd_ide.c boot device found
2929 -44 common/cmd_ide.c Device not available
2930 44 common/cmd_ide.c Device available
2931 -45 common/cmd_ide.c wrong partition selected
2932 45 common/cmd_ide.c partition selected
2933 -46 common/cmd_ide.c Unknown partition table
2934 46 common/cmd_ide.c valid partition table found
2935 -47 common/cmd_ide.c Invalid partition type
2936 47 common/cmd_ide.c correct partition type
2937 -48 common/cmd_ide.c Error reading Image Header on boot device
2938 48 common/cmd_ide.c reading Image Header from IDE device OK
2939 -49 common/cmd_ide.c Image header has bad magic number
2940 49 common/cmd_ide.c Image header has correct magic number
2941 -50 common/cmd_ide.c Image header has bad checksum
2942 50 common/cmd_ide.c Image header has correct checksum
2943 -51 common/cmd_ide.c Error reading Image from IDE device
2944 51 common/cmd_ide.c reading Image from IDE device OK
2945 52 common/cmd_nand.c before loading a Image from a NAND device
2946 -53 common/cmd_nand.c Bad usage of "nand" command
2947 53 common/cmd_nand.c correct usage of "nand" command
2948 -54 common/cmd_nand.c No boot device
2949 54 common/cmd_nand.c boot device found
2950 -55 common/cmd_nand.c Unknown Chip ID on boot device
2951 55 common/cmd_nand.c correct chip ID found, device available
2952 -56 common/cmd_nand.c Error reading Image Header on boot device
2953 56 common/cmd_nand.c reading Image Header from NAND device OK
2954 -57 common/cmd_nand.c Image header has bad magic number
2955 57 common/cmd_nand.c Image header has correct magic number
2956 -58 common/cmd_nand.c Error reading Image from NAND device
2957 58 common/cmd_nand.c reading Image from NAND device OK
2959 -60 common/env_common.c Environment has a bad CRC, using default
2961 64 net/eth.c starting with Ethernet configuration.
2962 -64 net/eth.c no Ethernet found.
2963 65 net/eth.c Ethernet found.
2965 -80 common/cmd_net.c usage wrong
2966 80 common/cmd_net.c before calling NetLoop()
2967 -81 common/cmd_net.c some error in NetLoop() occurred
2968 81 common/cmd_net.c NetLoop() back without error
2969 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2970 82 common/cmd_net.c trying automatic boot
2971 83 common/cmd_net.c running "source" command
2972 -83 common/cmd_net.c some error in automatic boot or "source" command
2973 84 common/cmd_net.c end without errors
2978 100 common/cmd_bootm.c Kernel FIT Image has correct format
2979 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2980 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2981 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2982 102 common/cmd_bootm.c Kernel unit name specified
2983 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2984 103 common/cmd_bootm.c Found configuration node
2985 104 common/cmd_bootm.c Got kernel subimage node offset
2986 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2987 105 common/cmd_bootm.c Kernel subimage hash verification OK
2988 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2989 106 common/cmd_bootm.c Architecture check OK
2990 -106 common/cmd_bootm.c Kernel subimage has wrong type
2991 107 common/cmd_bootm.c Kernel subimage type OK
2992 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2993 108 common/cmd_bootm.c Got kernel subimage data/size
2994 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2995 -109 common/cmd_bootm.c Can't get kernel subimage type
2996 -110 common/cmd_bootm.c Can't get kernel subimage comp
2997 -111 common/cmd_bootm.c Can't get kernel subimage os
2998 -112 common/cmd_bootm.c Can't get kernel subimage load address
2999 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3001 120 common/image.c Start initial ramdisk verification
3002 -120 common/image.c Ramdisk FIT image has incorrect format
3003 121 common/image.c Ramdisk FIT image has correct format
3004 122 common/image.c No ramdisk subimage unit name, using configuration
3005 -122 common/image.c Can't get configuration for ramdisk subimage
3006 123 common/image.c Ramdisk unit name specified
3007 -124 common/image.c Can't get ramdisk subimage node offset
3008 125 common/image.c Got ramdisk subimage node offset
3009 -125 common/image.c Ramdisk subimage hash verification failed
3010 126 common/image.c Ramdisk subimage hash verification OK
3011 -126 common/image.c Ramdisk subimage for unsupported architecture
3012 127 common/image.c Architecture check OK
3013 -127 common/image.c Can't get ramdisk subimage data/size
3014 128 common/image.c Got ramdisk subimage data/size
3015 129 common/image.c Can't get ramdisk load address
3016 -129 common/image.c Got ramdisk load address
3018 -130 common/cmd_doc.c Incorrect FIT image format
3019 131 common/cmd_doc.c FIT image format OK
3021 -140 common/cmd_ide.c Incorrect FIT image format
3022 141 common/cmd_ide.c FIT image format OK
3024 -150 common/cmd_nand.c Incorrect FIT image format
3025 151 common/cmd_nand.c FIT image format OK
3027 - FIT image support:
3029 Enable support for the FIT uImage format.
3031 CONFIG_FIT_BEST_MATCH
3032 When no configuration is explicitly selected, default to the
3033 one whose fdt's compatibility field best matches that of
3034 U-Boot itself. A match is considered "best" if it matches the
3035 most specific compatibility entry of U-Boot's fdt's root node.
3036 The order of entries in the configuration's fdt is ignored.
3038 CONFIG_FIT_SIGNATURE
3039 This option enables signature verification of FIT uImages,
3040 using a hash signed and verified using RSA. See
3041 doc/uImage.FIT/signature.txt for more details.
3043 - Standalone program support:
3044 CONFIG_STANDALONE_LOAD_ADDR
3046 This option defines a board specific value for the
3047 address where standalone program gets loaded, thus
3048 overwriting the architecture dependent default
3051 - Frame Buffer Address:
3054 Define CONFIG_FB_ADDR if you want to use specific
3055 address for frame buffer. This is typically the case
3056 when using a graphics controller has separate video
3057 memory. U-Boot will then place the frame buffer at
3058 the given address instead of dynamically reserving it
3059 in system RAM by calling lcd_setmem(), which grabs
3060 the memory for the frame buffer depending on the
3061 configured panel size.
3063 Please see board_init_f function.
3065 - Automatic software updates via TFTP server
3067 CONFIG_UPDATE_TFTP_CNT_MAX
3068 CONFIG_UPDATE_TFTP_MSEC_MAX
3070 These options enable and control the auto-update feature;
3071 for a more detailed description refer to doc/README.update.
3073 - MTD Support (mtdparts command, UBI support)
3076 Adds the MTD device infrastructure from the Linux kernel.
3077 Needed for mtdparts command support.
3079 CONFIG_MTD_PARTITIONS
3081 Adds the MTD partitioning infrastructure from the Linux
3082 kernel. Needed for UBI support.
3087 Adds commands for interacting with MTD partitions formatted
3088 with the UBI flash translation layer
3090 Requires also defining CONFIG_RBTREE
3092 CONFIG_UBI_SILENCE_MSG
3094 Make the verbose messages from UBI stop printing. This leaves
3095 warnings and errors enabled.
3100 Adds commands for interacting with UBI volumes formatted as
3101 UBIFS. UBIFS is read-only in u-boot.
3103 Requires UBI support as well as CONFIG_LZO
3105 CONFIG_UBIFS_SILENCE_MSG
3107 Make the verbose messages from UBIFS stop printing. This leaves
3108 warnings and errors enabled.
3112 Enable building of SPL globally.
3115 LDSCRIPT for linking the SPL binary.
3117 CONFIG_SPL_MAX_FOOTPRINT
3118 Maximum size in memory allocated to the SPL, BSS included.
3119 When defined, the linker checks that the actual memory
3120 used by SPL from _start to __bss_end does not exceed it.
3121 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3122 must not be both defined at the same time.
3125 Maximum size of the SPL image (text, data, rodata, and
3126 linker lists sections), BSS excluded.
3127 When defined, the linker checks that the actual size does
3130 CONFIG_SPL_TEXT_BASE
3131 TEXT_BASE for linking the SPL binary.
3133 CONFIG_SPL_RELOC_TEXT_BASE
3134 Address to relocate to. If unspecified, this is equal to
3135 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3137 CONFIG_SPL_BSS_START_ADDR
3138 Link address for the BSS within the SPL binary.
3140 CONFIG_SPL_BSS_MAX_SIZE
3141 Maximum size in memory allocated to the SPL BSS.
3142 When defined, the linker checks that the actual memory used
3143 by SPL from __bss_start to __bss_end does not exceed it.
3144 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3145 must not be both defined at the same time.
3148 Adress of the start of the stack SPL will use
3150 CONFIG_SPL_RELOC_STACK
3151 Adress of the start of the stack SPL will use after
3152 relocation. If unspecified, this is equal to
3155 CONFIG_SYS_SPL_MALLOC_START
3156 Starting address of the malloc pool used in SPL.
3158 CONFIG_SYS_SPL_MALLOC_SIZE
3159 The size of the malloc pool used in SPL.
3161 CONFIG_SPL_FRAMEWORK
3162 Enable the SPL framework under common/. This framework
3163 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3164 NAND loading of the Linux Kernel.
3166 CONFIG_SPL_DISPLAY_PRINT
3167 For ARM, enable an optional function to print more information
3168 about the running system.
3170 CONFIG_SPL_INIT_MINIMAL
3171 Arch init code should be built for a very small image
3173 CONFIG_SPL_LIBCOMMON_SUPPORT
3174 Support for common/libcommon.o in SPL binary
3176 CONFIG_SPL_LIBDISK_SUPPORT
3177 Support for disk/libdisk.o in SPL binary
3179 CONFIG_SPL_I2C_SUPPORT
3180 Support for drivers/i2c/libi2c.o in SPL binary
3182 CONFIG_SPL_GPIO_SUPPORT
3183 Support for drivers/gpio/libgpio.o in SPL binary
3185 CONFIG_SPL_MMC_SUPPORT
3186 Support for drivers/mmc/libmmc.o in SPL binary
3188 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3189 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3190 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3191 Address, size and partition on the MMC to load U-Boot from
3192 when the MMC is being used in raw mode.
3194 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3195 Sector to load kernel uImage from when MMC is being
3196 used in raw mode (for Falcon mode)
3198 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3199 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3200 Sector and number of sectors to load kernel argument
3201 parameters from when MMC is being used in raw mode
3204 CONFIG_SPL_FAT_SUPPORT
3205 Support for fs/fat/libfat.o in SPL binary
3207 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3208 Filename to read to load U-Boot when reading from FAT
3210 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3211 Filename to read to load kernel uImage when reading
3212 from FAT (for Falcon mode)
3214 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3215 Filename to read to load kernel argument parameters
3216 when reading from FAT (for Falcon mode)
3218 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3219 Set this for NAND SPL on PPC mpc83xx targets, so that
3220 start.S waits for the rest of the SPL to load before
3221 continuing (the hardware starts execution after just
3222 loading the first page rather than the full 4K).
3224 CONFIG_SPL_NAND_BASE
3225 Include nand_base.c in the SPL. Requires
3226 CONFIG_SPL_NAND_DRIVERS.
3228 CONFIG_SPL_NAND_DRIVERS
3229 SPL uses normal NAND drivers, not minimal drivers.
3232 Include standard software ECC in the SPL
3234 CONFIG_SPL_NAND_SIMPLE
3235 Support for NAND boot using simple NAND drivers that
3236 expose the cmd_ctrl() interface.
3238 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3239 Set for the SPL on PPC mpc8xxx targets, support for
3240 drivers/ddr/fsl/libddr.o in SPL binary.
3242 CONFIG_SPL_COMMON_INIT_DDR
3243 Set for common ddr init with serial presence detect in
3246 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3247 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3248 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3249 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3250 CONFIG_SYS_NAND_ECCBYTES
3251 Defines the size and behavior of the NAND that SPL uses
3254 CONFIG_SYS_NAND_U_BOOT_OFFS
3255 Location in NAND to read U-Boot from
3257 CONFIG_SYS_NAND_U_BOOT_DST
3258 Location in memory to load U-Boot to
3260 CONFIG_SYS_NAND_U_BOOT_SIZE
3261 Size of image to load
3263 CONFIG_SYS_NAND_U_BOOT_START
3264 Entry point in loaded image to jump to
3266 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3267 Define this if you need to first read the OOB and then the
3268 data. This is used for example on davinci plattforms.
3270 CONFIG_SPL_OMAP3_ID_NAND
3271 Support for an OMAP3-specific set of functions to return the
3272 ID and MFR of the first attached NAND chip, if present.
3274 CONFIG_SPL_SERIAL_SUPPORT
3275 Support for drivers/serial/libserial.o in SPL binary
3277 CONFIG_SPL_SPI_FLASH_SUPPORT
3278 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3280 CONFIG_SPL_SPI_SUPPORT
3281 Support for drivers/spi/libspi.o in SPL binary
3283 CONFIG_SPL_RAM_DEVICE
3284 Support for running image already present in ram, in SPL binary
3286 CONFIG_SPL_LIBGENERIC_SUPPORT
3287 Support for lib/libgeneric.o in SPL binary
3289 CONFIG_SPL_ENV_SUPPORT
3290 Support for the environment operating in SPL binary
3292 CONFIG_SPL_NET_SUPPORT
3293 Support for the net/libnet.o in SPL binary.
3294 It conflicts with SPL env from storage medium specified by
3295 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3298 Image offset to which the SPL should be padded before appending
3299 the SPL payload. By default, this is defined as
3300 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3301 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3302 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3305 Final target image containing SPL and payload. Some SPLs
3306 use an arch-specific makefile fragment instead, for
3307 example if more than one image needs to be produced.
3309 CONFIG_FIT_SPL_PRINT
3310 Printing information about a FIT image adds quite a bit of
3311 code to SPL. So this is normally disabled in SPL. Use this
3312 option to re-enable it. This will affect the output of the
3313 bootm command when booting a FIT image.
3317 Enable building of TPL globally.
3320 Image offset to which the TPL should be padded before appending
3321 the TPL payload. By default, this is defined as
3322 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3323 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3324 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3329 [so far only for SMDK2400 boards]
3331 - Modem support enable:
3332 CONFIG_MODEM_SUPPORT
3334 - RTS/CTS Flow control enable:
3337 - Modem debug support:
3338 CONFIG_MODEM_SUPPORT_DEBUG
3340 Enables debugging stuff (char screen[1024], dbg())
3341 for modem support. Useful only with BDI2000.
3343 - Interrupt support (PPC):
3345 There are common interrupt_init() and timer_interrupt()
3346 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3347 for CPU specific initialization. interrupt_init_cpu()
3348 should set decrementer_count to appropriate value. If
3349 CPU resets decrementer automatically after interrupt
3350 (ppc4xx) it should set decrementer_count to zero.
3351 timer_interrupt() calls timer_interrupt_cpu() for CPU
3352 specific handling. If board has watchdog / status_led
3353 / other_activity_monitor it works automatically from
3354 general timer_interrupt().
3358 In the target system modem support is enabled when a
3359 specific key (key combination) is pressed during
3360 power-on. Otherwise U-Boot will boot normally
3361 (autoboot). The key_pressed() function is called from
3362 board_init(). Currently key_pressed() is a dummy
3363 function, returning 1 and thus enabling modem
3366 If there are no modem init strings in the
3367 environment, U-Boot proceed to autoboot; the
3368 previous output (banner, info printfs) will be
3371 See also: doc/README.Modem
3373 Board initialization settings:
3374 ------------------------------
3376 During Initialization u-boot calls a number of board specific functions
3377 to allow the preparation of board specific prerequisites, e.g. pin setup
3378 before drivers are initialized. To enable these callbacks the
3379 following configuration macros have to be defined. Currently this is
3380 architecture specific, so please check arch/your_architecture/lib/board.c
3381 typically in board_init_f() and board_init_r().
3383 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3384 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3385 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3386 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3388 Configuration Settings:
3389 -----------------------
3391 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3392 undefine this when you're short of memory.
3394 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3395 width of the commands listed in the 'help' command output.
3397 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3398 prompt for user input.
3400 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3402 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3404 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3406 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3407 the application (usually a Linux kernel) when it is
3410 - CONFIG_SYS_BAUDRATE_TABLE:
3411 List of legal baudrate settings for this board.
3413 - CONFIG_SYS_CONSOLE_INFO_QUIET
3414 Suppress display of console information at boot.
3416 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3417 If the board specific function
3418 extern int overwrite_console (void);
3419 returns 1, the stdin, stderr and stdout are switched to the
3420 serial port, else the settings in the environment are used.
3422 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3423 Enable the call to overwrite_console().
3425 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3426 Enable overwrite of previous console environment settings.
3428 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3429 Begin and End addresses of the area used by the
3432 - CONFIG_SYS_ALT_MEMTEST:
3433 Enable an alternate, more extensive memory test.
3435 - CONFIG_SYS_MEMTEST_SCRATCH:
3436 Scratch address used by the alternate memory test
3437 You only need to set this if address zero isn't writeable
3439 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3440 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3441 this specified memory area will get subtracted from the top
3442 (end) of RAM and won't get "touched" at all by U-Boot. By
3443 fixing up gd->ram_size the Linux kernel should gets passed
3444 the now "corrected" memory size and won't touch it either.
3445 This should work for arch/ppc and arch/powerpc. Only Linux
3446 board ports in arch/powerpc with bootwrapper support that
3447 recalculate the memory size from the SDRAM controller setup
3448 will have to get fixed in Linux additionally.
3450 This option can be used as a workaround for the 440EPx/GRx
3451 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3454 WARNING: Please make sure that this value is a multiple of
3455 the Linux page size (normally 4k). If this is not the case,
3456 then the end address of the Linux memory will be located at a
3457 non page size aligned address and this could cause major
3460 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3461 Enable temporary baudrate change while serial download
3463 - CONFIG_SYS_SDRAM_BASE:
3464 Physical start address of SDRAM. _Must_ be 0 here.
3466 - CONFIG_SYS_MBIO_BASE:
3467 Physical start address of Motherboard I/O (if using a
3470 - CONFIG_SYS_FLASH_BASE:
3471 Physical start address of Flash memory.
3473 - CONFIG_SYS_MONITOR_BASE:
3474 Physical start address of boot monitor code (set by
3475 make config files to be same as the text base address
3476 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3477 CONFIG_SYS_FLASH_BASE when booting from flash.
3479 - CONFIG_SYS_MONITOR_LEN:
3480 Size of memory reserved for monitor code, used to
3481 determine _at_compile_time_ (!) if the environment is
3482 embedded within the U-Boot image, or in a separate
3485 - CONFIG_SYS_MALLOC_LEN:
3486 Size of DRAM reserved for malloc() use.
3488 - CONFIG_SYS_BOOTM_LEN:
3489 Normally compressed uImages are limited to an
3490 uncompressed size of 8 MBytes. If this is not enough,
3491 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3492 to adjust this setting to your needs.
3494 - CONFIG_SYS_BOOTMAPSZ:
3495 Maximum size of memory mapped by the startup code of
3496 the Linux kernel; all data that must be processed by
3497 the Linux kernel (bd_info, boot arguments, FDT blob if
3498 used) must be put below this limit, unless "bootm_low"
3499 environment variable is defined and non-zero. In such case
3500 all data for the Linux kernel must be between "bootm_low"
3501 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3502 variable "bootm_mapsize" will override the value of
3503 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3504 then the value in "bootm_size" will be used instead.
3506 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3507 Enable initrd_high functionality. If defined then the
3508 initrd_high feature is enabled and the bootm ramdisk subcommand
3511 - CONFIG_SYS_BOOT_GET_CMDLINE:
3512 Enables allocating and saving kernel cmdline in space between
3513 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3515 - CONFIG_SYS_BOOT_GET_KBD:
3516 Enables allocating and saving a kernel copy of the bd_info in
3517 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3519 - CONFIG_SYS_MAX_FLASH_BANKS:
3520 Max number of Flash memory banks
3522 - CONFIG_SYS_MAX_FLASH_SECT:
3523 Max number of sectors on a Flash chip
3525 - CONFIG_SYS_FLASH_ERASE_TOUT:
3526 Timeout for Flash erase operations (in ms)
3528 - CONFIG_SYS_FLASH_WRITE_TOUT:
3529 Timeout for Flash write operations (in ms)
3531 - CONFIG_SYS_FLASH_LOCK_TOUT
3532 Timeout for Flash set sector lock bit operation (in ms)
3534 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3535 Timeout for Flash clear lock bits operation (in ms)
3537 - CONFIG_SYS_FLASH_PROTECTION
3538 If defined, hardware flash sectors protection is used
3539 instead of U-Boot software protection.
3541 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3543 Enable TFTP transfers directly to flash memory;
3544 without this option such a download has to be
3545 performed in two steps: (1) download to RAM, and (2)
3546 copy from RAM to flash.
3548 The two-step approach is usually more reliable, since
3549 you can check if the download worked before you erase
3550 the flash, but in some situations (when system RAM is
3551 too limited to allow for a temporary copy of the
3552 downloaded image) this option may be very useful.
3554 - CONFIG_SYS_FLASH_CFI:
3555 Define if the flash driver uses extra elements in the
3556 common flash structure for storing flash geometry.
3558 - CONFIG_FLASH_CFI_DRIVER
3559 This option also enables the building of the cfi_flash driver
3560 in the drivers directory
3562 - CONFIG_FLASH_CFI_MTD
3563 This option enables the building of the cfi_mtd driver
3564 in the drivers directory. The driver exports CFI flash
3567 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3568 Use buffered writes to flash.
3570 - CONFIG_FLASH_SPANSION_S29WS_N
3571 s29ws-n MirrorBit flash has non-standard addresses for buffered
3574 - CONFIG_SYS_FLASH_QUIET_TEST
3575 If this option is defined, the common CFI flash doesn't
3576 print it's warning upon not recognized FLASH banks. This
3577 is useful, if some of the configured banks are only
3578 optionally available.
3580 - CONFIG_FLASH_SHOW_PROGRESS
3581 If defined (must be an integer), print out countdown
3582 digits and dots. Recommended value: 45 (9..1) for 80
3583 column displays, 15 (3..1) for 40 column displays.
3585 - CONFIG_FLASH_VERIFY
3586 If defined, the content of the flash (destination) is compared
3587 against the source after the write operation. An error message
3588 will be printed when the contents are not identical.
3589 Please note that this option is useless in nearly all cases,
3590 since such flash programming errors usually are detected earlier
3591 while unprotecting/erasing/programming. Please only enable
3592 this option if you really know what you are doing.
3594 - CONFIG_SYS_RX_ETH_BUFFER:
3595 Defines the number of Ethernet receive buffers. On some
3596 Ethernet controllers it is recommended to set this value
3597 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3598 buffers can be full shortly after enabling the interface
3599 on high Ethernet traffic.
3600 Defaults to 4 if not defined.
3602 - CONFIG_ENV_MAX_ENTRIES
3604 Maximum number of entries in the hash table that is used
3605 internally to store the environment settings. The default
3606 setting is supposed to be generous and should work in most
3607 cases. This setting can be used to tune behaviour; see
3608 lib/hashtable.c for details.
3610 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3611 - CONFIG_ENV_FLAGS_LIST_STATIC
3612 Enable validation of the values given to environment variables when
3613 calling env set. Variables can be restricted to only decimal,
3614 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3615 the variables can also be restricted to IP address or MAC address.
3617 The format of the list is:
3618 type_attribute = [s|d|x|b|i|m]
3619 access_atribute = [a|r|o|c]
3620 attributes = type_attribute[access_atribute]
3621 entry = variable_name[:attributes]
3624 The type attributes are:
3625 s - String (default)
3628 b - Boolean ([1yYtT|0nNfF])
3632 The access attributes are:
3638 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3639 Define this to a list (string) to define the ".flags"
3640 envirnoment variable in the default or embedded environment.
3642 - CONFIG_ENV_FLAGS_LIST_STATIC
3643 Define this to a list (string) to define validation that
3644 should be done if an entry is not found in the ".flags"
3645 environment variable. To override a setting in the static
3646 list, simply add an entry for the same variable name to the
3649 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3650 If defined, don't allow the -f switch to env set override variable
3653 - CONFIG_SYS_GENERIC_BOARD
3654 This selects the architecture-generic board system instead of the
3655 architecture-specific board files. It is intended to move boards
3656 to this new framework over time. Defining this will disable the
3657 arch/foo/lib/board.c file and use common/board_f.c and
3658 common/board_r.c instead. To use this option your architecture
3659 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3660 its config.mk file). If you find problems enabling this option on
3661 your board please report the problem and send patches!
3663 - CONFIG_SYS_SYM_OFFSETS
3664 This is set by architectures that use offsets for link symbols
3665 instead of absolute values. So bss_start is obtained using an
3666 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3667 directly. You should not need to touch this setting.
3669 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3670 This is set by OMAP boards for the max time that reset should
3671 be asserted. See doc/README.omap-reset-time for details on how
3672 the value can be calulated on a given board.
3674 The following definitions that deal with the placement and management
3675 of environment data (variable area); in general, we support the
3676 following configurations:
3678 - CONFIG_BUILD_ENVCRC:
3680 Builds up envcrc with the target environment so that external utils
3681 may easily extract it and embed it in final U-Boot images.
3683 - CONFIG_ENV_IS_IN_FLASH:
3685 Define this if the environment is in flash memory.
3687 a) The environment occupies one whole flash sector, which is
3688 "embedded" in the text segment with the U-Boot code. This
3689 happens usually with "bottom boot sector" or "top boot
3690 sector" type flash chips, which have several smaller
3691 sectors at the start or the end. For instance, such a
3692 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3693 such a case you would place the environment in one of the
3694 4 kB sectors - with U-Boot code before and after it. With
3695 "top boot sector" type flash chips, you would put the
3696 environment in one of the last sectors, leaving a gap
3697 between U-Boot and the environment.
3699 - CONFIG_ENV_OFFSET:
3701 Offset of environment data (variable area) to the
3702 beginning of flash memory; for instance, with bottom boot
3703 type flash chips the second sector can be used: the offset
3704 for this sector is given here.
3706 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3710 This is just another way to specify the start address of
3711 the flash sector containing the environment (instead of
3714 - CONFIG_ENV_SECT_SIZE:
3716 Size of the sector containing the environment.
3719 b) Sometimes flash chips have few, equal sized, BIG sectors.
3720 In such a case you don't want to spend a whole sector for
3725 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3726 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3727 of this flash sector for the environment. This saves
3728 memory for the RAM copy of the environment.
3730 It may also save flash memory if you decide to use this
3731 when your environment is "embedded" within U-Boot code,
3732 since then the remainder of the flash sector could be used
3733 for U-Boot code. It should be pointed out that this is
3734 STRONGLY DISCOURAGED from a robustness point of view:
3735 updating the environment in flash makes it always
3736 necessary to erase the WHOLE sector. If something goes
3737 wrong before the contents has been restored from a copy in
3738 RAM, your target system will be dead.
3740 - CONFIG_ENV_ADDR_REDUND
3741 CONFIG_ENV_SIZE_REDUND
3743 These settings describe a second storage area used to hold
3744 a redundant copy of the environment data, so that there is
3745 a valid backup copy in case there is a power failure during
3746 a "saveenv" operation.
3748 BE CAREFUL! Any changes to the flash layout, and some changes to the
3749 source code will make it necessary to adapt <board>/u-boot.lds*
3753 - CONFIG_ENV_IS_IN_NVRAM:
3755 Define this if you have some non-volatile memory device
3756 (NVRAM, battery buffered SRAM) which you want to use for the
3762 These two #defines are used to determine the memory area you
3763 want to use for environment. It is assumed that this memory
3764 can just be read and written to, without any special
3767 BE CAREFUL! The first access to the environment happens quite early
3768 in U-Boot initalization (when we try to get the setting of for the
3769 console baudrate). You *MUST* have mapped your NVRAM area then, or
3772 Please note that even with NVRAM we still use a copy of the
3773 environment in RAM: we could work on NVRAM directly, but we want to
3774 keep settings there always unmodified except somebody uses "saveenv"
3775 to save the current settings.
3778 - CONFIG_ENV_IS_IN_EEPROM:
3780 Use this if you have an EEPROM or similar serial access
3781 device and a driver for it.
3783 - CONFIG_ENV_OFFSET:
3786 These two #defines specify the offset and size of the
3787 environment area within the total memory of your EEPROM.
3789 - CONFIG_SYS_I2C_EEPROM_ADDR:
3790 If defined, specified the chip address of the EEPROM device.
3791 The default address is zero.
3793 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3794 If defined, the number of bits used to address bytes in a
3795 single page in the EEPROM device. A 64 byte page, for example
3796 would require six bits.
3798 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3799 If defined, the number of milliseconds to delay between
3800 page writes. The default is zero milliseconds.
3802 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3803 The length in bytes of the EEPROM memory array address. Note
3804 that this is NOT the chip address length!
3806 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3807 EEPROM chips that implement "address overflow" are ones
3808 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3809 address and the extra bits end up in the "chip address" bit
3810 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3813 Note that we consider the length of the address field to
3814 still be one byte because the extra address bits are hidden
3815 in the chip address.
3817 - CONFIG_SYS_EEPROM_SIZE:
3818 The size in bytes of the EEPROM device.
3820 - CONFIG_ENV_EEPROM_IS_ON_I2C
3821 define this, if you have I2C and SPI activated, and your
3822 EEPROM, which holds the environment, is on the I2C bus.
3824 - CONFIG_I2C_ENV_EEPROM_BUS
3825 if you have an Environment on an EEPROM reached over
3826 I2C muxes, you can define here, how to reach this
3827 EEPROM. For example:
3829 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3831 EEPROM which holds the environment, is reached over
3832 a pca9547 i2c mux with address 0x70, channel 3.
3834 - CONFIG_ENV_IS_IN_DATAFLASH:
3836 Define this if you have a DataFlash memory device which you
3837 want to use for the environment.
3839 - CONFIG_ENV_OFFSET:
3843 These three #defines specify the offset and size of the
3844 environment area within the total memory of your DataFlash placed
3845 at the specified address.
3847 - CONFIG_ENV_IS_IN_REMOTE:
3849 Define this if you have a remote memory space which you
3850 want to use for the local device's environment.
3855 These two #defines specify the address and size of the
3856 environment area within the remote memory space. The
3857 local device can get the environment from remote memory
3858 space by SRIO or PCIE links.
3860 BE CAREFUL! For some special cases, the local device can not use
3861 "saveenv" command. For example, the local device will get the
3862 environment stored in a remote NOR flash by SRIO or PCIE link,
3863 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3865 - CONFIG_ENV_IS_IN_NAND:
3867 Define this if you have a NAND device which you want to use
3868 for the environment.
3870 - CONFIG_ENV_OFFSET:
3873 These two #defines specify the offset and size of the environment
3874 area within the first NAND device. CONFIG_ENV_OFFSET must be
3875 aligned to an erase block boundary.
3877 - CONFIG_ENV_OFFSET_REDUND (optional):
3879 This setting describes a second storage area of CONFIG_ENV_SIZE
3880 size used to hold a redundant copy of the environment data, so
3881 that there is a valid backup copy in case there is a power failure
3882 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3883 aligned to an erase block boundary.
3885 - CONFIG_ENV_RANGE (optional):
3887 Specifies the length of the region in which the environment
3888 can be written. This should be a multiple of the NAND device's
3889 block size. Specifying a range with more erase blocks than
3890 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3891 the range to be avoided.
3893 - CONFIG_ENV_OFFSET_OOB (optional):
3895 Enables support for dynamically retrieving the offset of the
3896 environment from block zero's out-of-band data. The
3897 "nand env.oob" command can be used to record this offset.
3898 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3899 using CONFIG_ENV_OFFSET_OOB.
3901 - CONFIG_NAND_ENV_DST
3903 Defines address in RAM to which the nand_spl code should copy the
3904 environment. If redundant environment is used, it will be copied to
3905 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3907 - CONFIG_ENV_IS_IN_UBI:
3909 Define this if you have an UBI volume that you want to use for the
3910 environment. This has the benefit of wear-leveling the environment
3911 accesses, which is important on NAND.
3913 - CONFIG_ENV_UBI_PART:
3915 Define this to a string that is the mtd partition containing the UBI.
3917 - CONFIG_ENV_UBI_VOLUME:
3919 Define this to the name of the volume that you want to store the
3922 - CONFIG_ENV_UBI_VOLUME_REDUND:
3924 Define this to the name of another volume to store a second copy of
3925 the environment in. This will enable redundant environments in UBI.
3926 It is assumed that both volumes are in the same MTD partition.
3928 - CONFIG_UBI_SILENCE_MSG
3929 - CONFIG_UBIFS_SILENCE_MSG
3931 You will probably want to define these to avoid a really noisy system
3932 when storing the env in UBI.
3934 - CONFIG_ENV_IS_IN_MMC:
3936 Define this if you have an MMC device which you want to use for the
3939 - CONFIG_SYS_MMC_ENV_DEV:
3941 Specifies which MMC device the environment is stored in.
3943 - CONFIG_SYS_MMC_ENV_PART (optional):
3945 Specifies which MMC partition the environment is stored in. If not
3946 set, defaults to partition 0, the user area. Common values might be
3947 1 (first MMC boot partition), 2 (second MMC boot partition).
3949 - CONFIG_ENV_OFFSET:
3952 These two #defines specify the offset and size of the environment
3953 area within the specified MMC device.
3955 If offset is positive (the usual case), it is treated as relative to
3956 the start of the MMC partition. If offset is negative, it is treated
3957 as relative to the end of the MMC partition. This can be useful if
3958 your board may be fitted with different MMC devices, which have
3959 different sizes for the MMC partitions, and you always want the
3960 environment placed at the very end of the partition, to leave the
3961 maximum possible space before it, to store other data.
3963 These two values are in units of bytes, but must be aligned to an
3964 MMC sector boundary.
3966 - CONFIG_ENV_OFFSET_REDUND (optional):
3968 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3969 hold a redundant copy of the environment data. This provides a
3970 valid backup copy in case the other copy is corrupted, e.g. due
3971 to a power failure during a "saveenv" operation.
3973 This value may also be positive or negative; this is handled in the
3974 same way as CONFIG_ENV_OFFSET.
3976 This value is also in units of bytes, but must also be aligned to
3977 an MMC sector boundary.
3979 - CONFIG_ENV_SIZE_REDUND (optional):
3981 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3982 set. If this value is set, it must be set to the same value as
3985 - CONFIG_SYS_SPI_INIT_OFFSET
3987 Defines offset to the initial SPI buffer area in DPRAM. The
3988 area is used at an early stage (ROM part) if the environment
3989 is configured to reside in the SPI EEPROM: We need a 520 byte
3990 scratch DPRAM area. It is used between the two initialization
3991 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3992 to be a good choice since it makes it far enough from the
3993 start of the data area as well as from the stack pointer.
3995 Please note that the environment is read-only until the monitor
3996 has been relocated to RAM and a RAM copy of the environment has been
3997 created; also, when using EEPROM you will have to use getenv_f()
3998 until then to read environment variables.
4000 The environment is protected by a CRC32 checksum. Before the monitor
4001 is relocated into RAM, as a result of a bad CRC you will be working
4002 with the compiled-in default environment - *silently*!!! [This is
4003 necessary, because the first environment variable we need is the
4004 "baudrate" setting for the console - if we have a bad CRC, we don't
4005 have any device yet where we could complain.]
4007 Note: once the monitor has been relocated, then it will complain if
4008 the default environment is used; a new CRC is computed as soon as you
4009 use the "saveenv" command to store a valid environment.
4011 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4012 Echo the inverted Ethernet link state to the fault LED.
4014 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4015 also needs to be defined.
4017 - CONFIG_SYS_FAULT_MII_ADDR:
4018 MII address of the PHY to check for the Ethernet link state.
4020 - CONFIG_NS16550_MIN_FUNCTIONS:
4021 Define this if you desire to only have use of the NS16550_init
4022 and NS16550_putc functions for the serial driver located at
4023 drivers/serial/ns16550.c. This option is useful for saving
4024 space for already greatly restricted images, including but not
4025 limited to NAND_SPL configurations.
4027 - CONFIG_DISPLAY_BOARDINFO
4028 Display information about the board that U-Boot is running on
4029 when U-Boot starts up. The board function checkboard() is called
4032 - CONFIG_DISPLAY_BOARDINFO_LATE
4033 Similar to the previous option, but display this information
4034 later, once stdio is running and output goes to the LCD, if
4037 Low Level (hardware related) configuration options:
4038 ---------------------------------------------------
4040 - CONFIG_SYS_CACHELINE_SIZE:
4041 Cache Line Size of the CPU.
4043 - CONFIG_SYS_DEFAULT_IMMR:
4044 Default address of the IMMR after system reset.
4046 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4047 and RPXsuper) to be able to adjust the position of
4048 the IMMR register after a reset.
4050 - CONFIG_SYS_CCSRBAR_DEFAULT:
4051 Default (power-on reset) physical address of CCSR on Freescale
4054 - CONFIG_SYS_CCSRBAR:
4055 Virtual address of CCSR. On a 32-bit build, this is typically
4056 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4058 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4059 for cross-platform code that uses that macro instead.
4061 - CONFIG_SYS_CCSRBAR_PHYS:
4062 Physical address of CCSR. CCSR can be relocated to a new
4063 physical address, if desired. In this case, this macro should
4064 be set to that address. Otherwise, it should be set to the
4065 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4066 is typically relocated on 36-bit builds. It is recommended
4067 that this macro be defined via the _HIGH and _LOW macros:
4069 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4070 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4072 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4073 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4074 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4075 used in assembly code, so it must not contain typecasts or
4076 integer size suffixes (e.g. "ULL").
4078 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4079 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4080 used in assembly code, so it must not contain typecasts or
4081 integer size suffixes (e.g. "ULL").
4083 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4084 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4085 forced to a value that ensures that CCSR is not relocated.
4087 - Floppy Disk Support:
4088 CONFIG_SYS_FDC_DRIVE_NUMBER
4090 the default drive number (default value 0)
4092 CONFIG_SYS_ISA_IO_STRIDE
4094 defines the spacing between FDC chipset registers
4097 CONFIG_SYS_ISA_IO_OFFSET
4099 defines the offset of register from address. It
4100 depends on which part of the data bus is connected to
4101 the FDC chipset. (default value 0)
4103 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4104 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4107 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4108 fdc_hw_init() is called at the beginning of the FDC
4109 setup. fdc_hw_init() must be provided by the board
4110 source code. It is used to make hardware dependant
4114 Most IDE controllers were designed to be connected with PCI
4115 interface. Only few of them were designed for AHB interface.
4116 When software is doing ATA command and data transfer to
4117 IDE devices through IDE-AHB controller, some additional
4118 registers accessing to these kind of IDE-AHB controller
4121 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4122 DO NOT CHANGE unless you know exactly what you're
4123 doing! (11-4) [MPC8xx/82xx systems only]
4125 - CONFIG_SYS_INIT_RAM_ADDR:
4127 Start address of memory area that can be used for
4128 initial data and stack; please note that this must be
4129 writable memory that is working WITHOUT special
4130 initialization, i. e. you CANNOT use normal RAM which
4131 will become available only after programming the
4132 memory controller and running certain initialization
4135 U-Boot uses the following memory types:
4136 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4137 - MPC824X: data cache
4138 - PPC4xx: data cache
4140 - CONFIG_SYS_GBL_DATA_OFFSET:
4142 Offset of the initial data structure in the memory
4143 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4144 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4145 data is located at the end of the available space
4146 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4147 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4148 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4149 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4152 On the MPC824X (or other systems that use the data
4153 cache for initial memory) the address chosen for
4154 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4155 point to an otherwise UNUSED address space between
4156 the top of RAM and the start of the PCI space.
4158 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4160 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4162 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4164 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4166 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4168 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4170 - CONFIG_SYS_OR_TIMING_SDRAM:
4173 - CONFIG_SYS_MAMR_PTA:
4174 periodic timer for refresh
4176 - CONFIG_SYS_DER: Debug Event Register (37-47)
4178 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4179 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4180 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4181 CONFIG_SYS_BR1_PRELIM:
4182 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4184 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4185 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4186 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4187 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4189 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4190 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4191 Machine Mode Register and Memory Periodic Timer
4192 Prescaler definitions (SDRAM timing)
4194 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4195 enable I2C microcode relocation patch (MPC8xx);
4196 define relocation offset in DPRAM [DSP2]
4198 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4199 enable SMC microcode relocation patch (MPC8xx);
4200 define relocation offset in DPRAM [SMC1]
4202 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4203 enable SPI microcode relocation patch (MPC8xx);
4204 define relocation offset in DPRAM [SCC4]
4206 - CONFIG_SYS_USE_OSCCLK:
4207 Use OSCM clock mode on MBX8xx board. Be careful,
4208 wrong setting might damage your board. Read
4209 doc/README.MBX before setting this variable!
4211 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4212 Offset of the bootmode word in DPRAM used by post
4213 (Power On Self Tests). This definition overrides
4214 #define'd default value in commproc.h resp.
4217 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4218 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4219 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4220 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4221 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4222 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4223 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4224 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4225 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4227 - CONFIG_PCI_DISABLE_PCIE:
4228 Disable PCI-Express on systems where it is supported but not
4231 - CONFIG_PCI_ENUM_ONLY
4232 Only scan through and get the devices on the busses.
4233 Don't do any setup work, presumably because someone or
4234 something has already done it, and we don't need to do it
4235 a second time. Useful for platforms that are pre-booted
4236 by coreboot or similar.
4238 - CONFIG_PCI_INDIRECT_BRIDGE:
4239 Enable support for indirect PCI bridges.
4242 Chip has SRIO or not
4245 Board has SRIO 1 port available
4248 Board has SRIO 2 port available
4250 - CONFIG_SRIO_PCIE_BOOT_MASTER
4251 Board can support master function for Boot from SRIO and PCIE
4253 - CONFIG_SYS_SRIOn_MEM_VIRT:
4254 Virtual Address of SRIO port 'n' memory region
4256 - CONFIG_SYS_SRIOn_MEM_PHYS:
4257 Physical Address of SRIO port 'n' memory region
4259 - CONFIG_SYS_SRIOn_MEM_SIZE:
4260 Size of SRIO port 'n' memory region
4262 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4263 Defined to tell the NAND controller that the NAND chip is using
4265 Not all NAND drivers use this symbol.
4266 Example of drivers that use it:
4267 - drivers/mtd/nand/ndfc.c
4268 - drivers/mtd/nand/mxc_nand.c
4270 - CONFIG_SYS_NDFC_EBC0_CFG
4271 Sets the EBC0_CFG register for the NDFC. If not defined
4272 a default value will be used.
4275 Get DDR timing information from an I2C EEPROM. Common
4276 with pluggable memory modules such as SODIMMs
4279 I2C address of the SPD EEPROM
4281 - CONFIG_SYS_SPD_BUS_NUM
4282 If SPD EEPROM is on an I2C bus other than the first
4283 one, specify here. Note that the value must resolve
4284 to something your driver can deal with.
4286 - CONFIG_SYS_DDR_RAW_TIMING
4287 Get DDR timing information from other than SPD. Common with
4288 soldered DDR chips onboard without SPD. DDR raw timing
4289 parameters are extracted from datasheet and hard-coded into
4290 header files or board specific files.
4292 - CONFIG_FSL_DDR_INTERACTIVE
4293 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4295 - CONFIG_SYS_83XX_DDR_USES_CS0
4296 Only for 83xx systems. If specified, then DDR should
4297 be configured using CS0 and CS1 instead of CS2 and CS3.
4299 - CONFIG_ETHER_ON_FEC[12]
4300 Define to enable FEC[12] on a 8xx series processor.
4302 - CONFIG_FEC[12]_PHY
4303 Define to the hardcoded PHY address which corresponds
4304 to the given FEC; i. e.
4305 #define CONFIG_FEC1_PHY 4
4306 means that the PHY with address 4 is connected to FEC1
4308 When set to -1, means to probe for first available.
4310 - CONFIG_FEC[12]_PHY_NORXERR
4311 The PHY does not have a RXERR line (RMII only).
4312 (so program the FEC to ignore it).
4315 Enable RMII mode for all FECs.
4316 Note that this is a global option, we can't
4317 have one FEC in standard MII mode and another in RMII mode.
4319 - CONFIG_CRC32_VERIFY
4320 Add a verify option to the crc32 command.
4323 => crc32 -v <address> <count> <crc32>
4325 Where address/count indicate a memory area
4326 and crc32 is the correct crc32 which the
4330 Add the "loopw" memory command. This only takes effect if
4331 the memory commands are activated globally (CONFIG_CMD_MEM).
4334 Add the "mdc" and "mwc" memory commands. These are cyclic
4339 This command will print 4 bytes (10,11,12,13) each 500 ms.
4341 => mwc.l 100 12345678 10
4342 This command will write 12345678 to address 100 all 10 ms.
4344 This only takes effect if the memory commands are activated
4345 globally (CONFIG_CMD_MEM).
4347 - CONFIG_SKIP_LOWLEVEL_INIT
4348 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4349 low level initializations (like setting up the memory
4350 controller) are omitted and/or U-Boot does not
4351 relocate itself into RAM.
4353 Normally this variable MUST NOT be defined. The only
4354 exception is when U-Boot is loaded (to RAM) by some
4355 other boot loader or by a debugger which performs
4356 these initializations itself.
4359 Modifies the behaviour of start.S when compiling a loader
4360 that is executed before the actual U-Boot. E.g. when
4361 compiling a NAND SPL.
4364 Modifies the behaviour of start.S when compiling a loader
4365 that is executed after the SPL and before the actual U-Boot.
4366 It is loaded by the SPL.
4368 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4369 Only for 85xx systems. If this variable is specified, the section
4370 .resetvec is not kept and the section .bootpg is placed in the
4371 previous 4k of the .text section.
4373 - CONFIG_ARCH_MAP_SYSMEM
4374 Generally U-Boot (and in particular the md command) uses
4375 effective address. It is therefore not necessary to regard
4376 U-Boot address as virtual addresses that need to be translated
4377 to physical addresses. However, sandbox requires this, since
4378 it maintains its own little RAM buffer which contains all
4379 addressable memory. This option causes some memory accesses
4380 to be mapped through map_sysmem() / unmap_sysmem().
4382 - CONFIG_USE_ARCH_MEMCPY
4383 CONFIG_USE_ARCH_MEMSET
4384 If these options are used a optimized version of memcpy/memset will
4385 be used if available. These functions may be faster under some
4386 conditions but may increase the binary size.
4388 - CONFIG_X86_RESET_VECTOR
4389 If defined, the x86 reset vector code is included. This is not
4390 needed when U-Boot is running from Coreboot.
4393 Defines the MPU clock speed (in MHz).
4395 NOTE : currently only supported on AM335x platforms.
4397 Freescale QE/FMAN Firmware Support:
4398 -----------------------------------
4400 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4401 loading of "firmware", which is encoded in the QE firmware binary format.
4402 This firmware often needs to be loaded during U-Boot booting, so macros
4403 are used to identify the storage device (NOR flash, SPI, etc) and the address
4406 - CONFIG_SYS_QE_FMAN_FW_ADDR
4407 The address in the storage device where the firmware is located. The
4408 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4411 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4412 The maximum possible size of the firmware. The firmware binary format
4413 has a field that specifies the actual size of the firmware, but it
4414 might not be possible to read any part of the firmware unless some
4415 local storage is allocated to hold the entire firmware first.
4417 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4418 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4419 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4420 virtual address in NOR flash.
4422 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4423 Specifies that QE/FMAN firmware is located in NAND flash.
4424 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4426 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4427 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4428 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4430 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4431 Specifies that QE/FMAN firmware is located on the primary SPI
4432 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4434 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4435 Specifies that QE/FMAN firmware is located in the remote (master)
4436 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4437 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4438 window->master inbound window->master LAW->the ucode address in
4439 master's memory space.
4441 Building the Software:
4442 ======================
4444 Building U-Boot has been tested in several native build environments
4445 and in many different cross environments. Of course we cannot support
4446 all possibly existing versions of cross development tools in all
4447 (potentially obsolete) versions. In case of tool chain problems we
4448 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4449 which is extensively used to build and test U-Boot.
4451 If you are not using a native environment, it is assumed that you
4452 have GNU cross compiling tools available in your path. In this case,
4453 you must set the environment variable CROSS_COMPILE in your shell.
4454 Note that no changes to the Makefile or any other source files are
4455 necessary. For example using the ELDK on a 4xx CPU, please enter:
4457 $ CROSS_COMPILE=ppc_4xx-
4458 $ export CROSS_COMPILE
4460 Note: If you wish to generate Windows versions of the utilities in
4461 the tools directory you can use the MinGW toolchain
4462 (http://www.mingw.org). Set your HOST tools to the MinGW
4463 toolchain and execute 'make tools'. For example:
4465 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4467 Binaries such as tools/mkimage.exe will be created which can
4468 be executed on computers running Windows.
4470 U-Boot is intended to be simple to build. After installing the
4471 sources you must configure U-Boot for one specific board type. This
4476 where "NAME_config" is the name of one of the existing configu-
4477 rations; see boards.cfg for supported names.
4479 Note: for some board special configuration names may exist; check if
4480 additional information is available from the board vendor; for
4481 instance, the TQM823L systems are available without (standard)
4482 or with LCD support. You can select such additional "features"
4483 when choosing the configuration, i. e.
4486 - will configure for a plain TQM823L, i. e. no LCD support
4488 make TQM823L_LCD_config
4489 - will configure for a TQM823L with U-Boot console on LCD
4494 Finally, type "make all", and you should get some working U-Boot
4495 images ready for download to / installation on your system:
4497 - "u-boot.bin" is a raw binary image
4498 - "u-boot" is an image in ELF binary format
4499 - "u-boot.srec" is in Motorola S-Record format
4501 By default the build is performed locally and the objects are saved
4502 in the source directory. One of the two methods can be used to change
4503 this behavior and build U-Boot to some external directory:
4505 1. Add O= to the make command line invocations:
4507 make O=/tmp/build distclean
4508 make O=/tmp/build NAME_config
4509 make O=/tmp/build all
4511 2. Set environment variable BUILD_DIR to point to the desired location:
4513 export BUILD_DIR=/tmp/build
4518 Note that the command line "O=" setting overrides the BUILD_DIR environment
4522 Please be aware that the Makefiles assume you are using GNU make, so
4523 for instance on NetBSD you might need to use "gmake" instead of
4527 If the system board that you have is not listed, then you will need
4528 to port U-Boot to your hardware platform. To do this, follow these
4531 1. Add a new configuration option for your board to the toplevel
4532 "boards.cfg" file, using the existing entries as examples.
4533 Follow the instructions there to keep the boards in order.
4534 2. Create a new directory to hold your board specific code. Add any
4535 files you need. In your board directory, you will need at least
4536 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4537 3. Create a new configuration file "include/configs/<board>.h" for
4539 3. If you're porting U-Boot to a new CPU, then also create a new
4540 directory to hold your CPU specific code. Add any files you need.
4541 4. Run "make <board>_config" with your new name.
4542 5. Type "make", and you should get a working "u-boot.srec" file
4543 to be installed on your target system.
4544 6. Debug and solve any problems that might arise.
4545 [Of course, this last step is much harder than it sounds.]
4548 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4549 ==============================================================
4551 If you have modified U-Boot sources (for instance added a new board
4552 or support for new devices, a new CPU, etc.) you are expected to
4553 provide feedback to the other developers. The feedback normally takes
4554 the form of a "patch", i. e. a context diff against a certain (latest
4555 official or latest in the git repository) version of U-Boot sources.
4557 But before you submit such a patch, please verify that your modifi-
4558 cation did not break existing code. At least make sure that *ALL* of
4559 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4560 just run the "MAKEALL" script, which will configure and build U-Boot
4561 for ALL supported system. Be warned, this will take a while. You can
4562 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4563 environment variable to the script, i. e. to use the ELDK cross tools
4566 CROSS_COMPILE=ppc_8xx- MAKEALL
4568 or to build on a native PowerPC system you can type
4570 CROSS_COMPILE=' ' MAKEALL
4572 When using the MAKEALL script, the default behaviour is to build
4573 U-Boot in the source directory. This location can be changed by
4574 setting the BUILD_DIR environment variable. Also, for each target
4575 built, the MAKEALL script saves two log files (<target>.ERR and
4576 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4577 location can be changed by setting the MAKEALL_LOGDIR environment
4578 variable. For example:
4580 export BUILD_DIR=/tmp/build
4581 export MAKEALL_LOGDIR=/tmp/log
4582 CROSS_COMPILE=ppc_8xx- MAKEALL
4584 With the above settings build objects are saved in the /tmp/build,
4585 log files are saved in the /tmp/log and the source tree remains clean
4586 during the whole build process.
4589 See also "U-Boot Porting Guide" below.
4592 Monitor Commands - Overview:
4593 ============================
4595 go - start application at address 'addr'
4596 run - run commands in an environment variable
4597 bootm - boot application image from memory
4598 bootp - boot image via network using BootP/TFTP protocol
4599 bootz - boot zImage from memory
4600 tftpboot- boot image via network using TFTP protocol
4601 and env variables "ipaddr" and "serverip"
4602 (and eventually "gatewayip")
4603 tftpput - upload a file via network using TFTP protocol
4604 rarpboot- boot image via network using RARP/TFTP protocol
4605 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4606 loads - load S-Record file over serial line
4607 loadb - load binary file over serial line (kermit mode)
4609 mm - memory modify (auto-incrementing)
4610 nm - memory modify (constant address)
4611 mw - memory write (fill)
4613 cmp - memory compare
4614 crc32 - checksum calculation
4615 i2c - I2C sub-system
4616 sspi - SPI utility commands
4617 base - print or set address offset
4618 printenv- print environment variables
4619 setenv - set environment variables
4620 saveenv - save environment variables to persistent storage
4621 protect - enable or disable FLASH write protection
4622 erase - erase FLASH memory
4623 flinfo - print FLASH memory information
4624 nand - NAND memory operations (see doc/README.nand)
4625 bdinfo - print Board Info structure
4626 iminfo - print header information for application image
4627 coninfo - print console devices and informations
4628 ide - IDE sub-system
4629 loop - infinite loop on address range
4630 loopw - infinite write loop on address range
4631 mtest - simple RAM test
4632 icache - enable or disable instruction cache
4633 dcache - enable or disable data cache
4634 reset - Perform RESET of the CPU
4635 echo - echo args to console
4636 version - print monitor version
4637 help - print online help
4638 ? - alias for 'help'
4641 Monitor Commands - Detailed Description:
4642 ========================================
4646 For now: just type "help <command>".
4649 Environment Variables:
4650 ======================
4652 U-Boot supports user configuration using Environment Variables which
4653 can be made persistent by saving to Flash memory.
4655 Environment Variables are set using "setenv", printed using
4656 "printenv", and saved to Flash using "saveenv". Using "setenv"
4657 without a value can be used to delete a variable from the
4658 environment. As long as you don't save the environment you are
4659 working with an in-memory copy. In case the Flash area containing the
4660 environment is erased by accident, a default environment is provided.
4662 Some configuration options can be set using Environment Variables.
4664 List of environment variables (most likely not complete):
4666 baudrate - see CONFIG_BAUDRATE
4668 bootdelay - see CONFIG_BOOTDELAY
4670 bootcmd - see CONFIG_BOOTCOMMAND
4672 bootargs - Boot arguments when booting an RTOS image
4674 bootfile - Name of the image to load with TFTP
4676 bootm_low - Memory range available for image processing in the bootm
4677 command can be restricted. This variable is given as
4678 a hexadecimal number and defines lowest address allowed
4679 for use by the bootm command. See also "bootm_size"
4680 environment variable. Address defined by "bootm_low" is
4681 also the base of the initial memory mapping for the Linux
4682 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4685 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4686 This variable is given as a hexadecimal number and it
4687 defines the size of the memory region starting at base
4688 address bootm_low that is accessible by the Linux kernel
4689 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4690 as the default value if it is defined, and bootm_size is
4693 bootm_size - Memory range available for image processing in the bootm
4694 command can be restricted. This variable is given as
4695 a hexadecimal number and defines the size of the region
4696 allowed for use by the bootm command. See also "bootm_low"
4697 environment variable.
4699 updatefile - Location of the software update file on a TFTP server, used
4700 by the automatic software update feature. Please refer to
4701 documentation in doc/README.update for more details.
4703 autoload - if set to "no" (any string beginning with 'n'),
4704 "bootp" will just load perform a lookup of the
4705 configuration from the BOOTP server, but not try to
4706 load any image using TFTP
4708 autostart - if set to "yes", an image loaded using the "bootp",
4709 "rarpboot", "tftpboot" or "diskboot" commands will
4710 be automatically started (by internally calling
4713 If set to "no", a standalone image passed to the
4714 "bootm" command will be copied to the load address
4715 (and eventually uncompressed), but NOT be started.
4716 This can be used to load and uncompress arbitrary
4719 fdt_high - if set this restricts the maximum address that the
4720 flattened device tree will be copied into upon boot.
4721 For example, if you have a system with 1 GB memory
4722 at physical address 0x10000000, while Linux kernel
4723 only recognizes the first 704 MB as low memory, you
4724 may need to set fdt_high as 0x3C000000 to have the
4725 device tree blob be copied to the maximum address
4726 of the 704 MB low memory, so that Linux kernel can
4727 access it during the boot procedure.
4729 If this is set to the special value 0xFFFFFFFF then
4730 the fdt will not be copied at all on boot. For this
4731 to work it must reside in writable memory, have
4732 sufficient padding on the end of it for u-boot to
4733 add the information it needs into it, and the memory
4734 must be accessible by the kernel.
4736 fdtcontroladdr- if set this is the address of the control flattened
4737 device tree used by U-Boot when CONFIG_OF_CONTROL is
4740 i2cfast - (PPC405GP|PPC405EP only)
4741 if set to 'y' configures Linux I2C driver for fast
4742 mode (400kHZ). This environment variable is used in
4743 initialization code. So, for changes to be effective
4744 it must be saved and board must be reset.
4746 initrd_high - restrict positioning of initrd images:
4747 If this variable is not set, initrd images will be
4748 copied to the highest possible address in RAM; this
4749 is usually what you want since it allows for
4750 maximum initrd size. If for some reason you want to
4751 make sure that the initrd image is loaded below the
4752 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4753 variable to a value of "no" or "off" or "0".
4754 Alternatively, you can set it to a maximum upper
4755 address to use (U-Boot will still check that it
4756 does not overwrite the U-Boot stack and data).
4758 For instance, when you have a system with 16 MB
4759 RAM, and want to reserve 4 MB from use by Linux,
4760 you can do this by adding "mem=12M" to the value of
4761 the "bootargs" variable. However, now you must make
4762 sure that the initrd image is placed in the first
4763 12 MB as well - this can be done with
4765 setenv initrd_high 00c00000
4767 If you set initrd_high to 0xFFFFFFFF, this is an
4768 indication to U-Boot that all addresses are legal
4769 for the Linux kernel, including addresses in flash
4770 memory. In this case U-Boot will NOT COPY the
4771 ramdisk at all. This may be useful to reduce the
4772 boot time on your system, but requires that this
4773 feature is supported by your Linux kernel.
4775 ipaddr - IP address; needed for tftpboot command
4777 loadaddr - Default load address for commands like "bootp",
4778 "rarpboot", "tftpboot", "loadb" or "diskboot"
4780 loads_echo - see CONFIG_LOADS_ECHO
4782 serverip - TFTP server IP address; needed for tftpboot command
4784 bootretry - see CONFIG_BOOT_RETRY_TIME
4786 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4788 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4790 ethprime - controls which interface is used first.
4792 ethact - controls which interface is currently active.
4793 For example you can do the following
4795 => setenv ethact FEC
4796 => ping 192.168.0.1 # traffic sent on FEC
4797 => setenv ethact SCC
4798 => ping 10.0.0.1 # traffic sent on SCC
4800 ethrotate - When set to "no" U-Boot does not go through all
4801 available network interfaces.
4802 It just stays at the currently selected interface.
4804 netretry - When set to "no" each network operation will
4805 either succeed or fail without retrying.
4806 When set to "once" the network operation will
4807 fail when all the available network interfaces
4808 are tried once without success.
4809 Useful on scripts which control the retry operation
4812 npe_ucode - set load address for the NPE microcode
4814 silent_linux - If set then linux will be told to boot silently, by
4815 changing the console to be empty. If "yes" it will be
4816 made silent. If "no" it will not be made silent. If
4817 unset, then it will be made silent if the U-Boot console
4820 tftpsrcport - If this is set, the value is used for TFTP's
4823 tftpdstport - If this is set, the value is used for TFTP's UDP
4824 destination port instead of the Well Know Port 69.
4826 tftpblocksize - Block size to use for TFTP transfers; if not set,
4827 we use the TFTP server's default block size
4829 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4830 seconds, minimum value is 1000 = 1 second). Defines
4831 when a packet is considered to be lost so it has to
4832 be retransmitted. The default is 5000 = 5 seconds.
4833 Lowering this value may make downloads succeed
4834 faster in networks with high packet loss rates or
4835 with unreliable TFTP servers.
4837 vlan - When set to a value < 4095 the traffic over
4838 Ethernet is encapsulated/received over 802.1q
4841 The following image location variables contain the location of images
4842 used in booting. The "Image" column gives the role of the image and is
4843 not an environment variable name. The other columns are environment
4844 variable names. "File Name" gives the name of the file on a TFTP
4845 server, "RAM Address" gives the location in RAM the image will be
4846 loaded to, and "Flash Location" gives the image's address in NOR
4847 flash or offset in NAND flash.
4849 *Note* - these variables don't have to be defined for all boards, some
4850 boards currenlty use other variables for these purposes, and some
4851 boards use these variables for other purposes.
4853 Image File Name RAM Address Flash Location
4854 ----- --------- ----------- --------------
4855 u-boot u-boot u-boot_addr_r u-boot_addr
4856 Linux kernel bootfile kernel_addr_r kernel_addr
4857 device tree blob fdtfile fdt_addr_r fdt_addr
4858 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4860 The following environment variables may be used and automatically
4861 updated by the network boot commands ("bootp" and "rarpboot"),
4862 depending the information provided by your boot server:
4864 bootfile - see above
4865 dnsip - IP address of your Domain Name Server
4866 dnsip2 - IP address of your secondary Domain Name Server
4867 gatewayip - IP address of the Gateway (Router) to use
4868 hostname - Target hostname
4870 netmask - Subnet Mask
4871 rootpath - Pathname of the root filesystem on the NFS server
4872 serverip - see above
4875 There are two special Environment Variables:
4877 serial# - contains hardware identification information such
4878 as type string and/or serial number
4879 ethaddr - Ethernet address
4881 These variables can be set only once (usually during manufacturing of
4882 the board). U-Boot refuses to delete or overwrite these variables
4883 once they have been set once.
4886 Further special Environment Variables:
4888 ver - Contains the U-Boot version string as printed
4889 with the "version" command. This variable is
4890 readonly (see CONFIG_VERSION_VARIABLE).
4893 Please note that changes to some configuration parameters may take
4894 only effect after the next boot (yes, that's just like Windoze :-).
4897 Callback functions for environment variables:
4898 ---------------------------------------------
4900 For some environment variables, the behavior of u-boot needs to change
4901 when their values are changed. This functionailty allows functions to
4902 be associated with arbitrary variables. On creation, overwrite, or
4903 deletion, the callback will provide the opportunity for some side
4904 effect to happen or for the change to be rejected.
4906 The callbacks are named and associated with a function using the
4907 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4909 These callbacks are associated with variables in one of two ways. The
4910 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4911 in the board configuration to a string that defines a list of
4912 associations. The list must be in the following format:
4914 entry = variable_name[:callback_name]
4917 If the callback name is not specified, then the callback is deleted.
4918 Spaces are also allowed anywhere in the list.
4920 Callbacks can also be associated by defining the ".callbacks" variable
4921 with the same list format above. Any association in ".callbacks" will
4922 override any association in the static list. You can define
4923 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4924 ".callbacks" envirnoment variable in the default or embedded environment.
4927 Command Line Parsing:
4928 =====================
4930 There are two different command line parsers available with U-Boot:
4931 the old "simple" one, and the much more powerful "hush" shell:
4933 Old, simple command line parser:
4934 --------------------------------
4936 - supports environment variables (through setenv / saveenv commands)
4937 - several commands on one line, separated by ';'
4938 - variable substitution using "... ${name} ..." syntax
4939 - special characters ('$', ';') can be escaped by prefixing with '\',
4941 setenv bootcmd bootm \${address}
4942 - You can also escape text by enclosing in single apostrophes, for example:
4943 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4948 - similar to Bourne shell, with control structures like
4949 if...then...else...fi, for...do...done; while...do...done,
4950 until...do...done, ...
4951 - supports environment ("global") variables (through setenv / saveenv
4952 commands) and local shell variables (through standard shell syntax
4953 "name=value"); only environment variables can be used with "run"
4959 (1) If a command line (or an environment variable executed by a "run"
4960 command) contains several commands separated by semicolon, and
4961 one of these commands fails, then the remaining commands will be
4964 (2) If you execute several variables with one call to run (i. e.
4965 calling run with a list of variables as arguments), any failing
4966 command will cause "run" to terminate, i. e. the remaining
4967 variables are not executed.
4969 Note for Redundant Ethernet Interfaces:
4970 =======================================
4972 Some boards come with redundant Ethernet interfaces; U-Boot supports
4973 such configurations and is capable of automatic selection of a
4974 "working" interface when needed. MAC assignment works as follows:
4976 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4977 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4978 "eth1addr" (=>eth1), "eth2addr", ...
4980 If the network interface stores some valid MAC address (for instance
4981 in SROM), this is used as default address if there is NO correspon-
4982 ding setting in the environment; if the corresponding environment
4983 variable is set, this overrides the settings in the card; that means:
4985 o If the SROM has a valid MAC address, and there is no address in the
4986 environment, the SROM's address is used.
4988 o If there is no valid address in the SROM, and a definition in the
4989 environment exists, then the value from the environment variable is
4992 o If both the SROM and the environment contain a MAC address, and
4993 both addresses are the same, this MAC address is used.
4995 o If both the SROM and the environment contain a MAC address, and the
4996 addresses differ, the value from the environment is used and a
4999 o If neither SROM nor the environment contain a MAC address, an error
5002 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5003 will be programmed into hardware as part of the initialization process. This
5004 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5005 The naming convention is as follows:
5006 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5011 U-Boot is capable of booting (and performing other auxiliary operations on)
5012 images in two formats:
5014 New uImage format (FIT)
5015 -----------------------
5017 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5018 to Flattened Device Tree). It allows the use of images with multiple
5019 components (several kernels, ramdisks, etc.), with contents protected by
5020 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5026 Old image format is based on binary files which can be basically anything,
5027 preceded by a special header; see the definitions in include/image.h for
5028 details; basically, the header defines the following image properties:
5030 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5031 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5032 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5033 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5035 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5036 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5037 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5038 * Compression Type (uncompressed, gzip, bzip2)
5044 The header is marked by a special Magic Number, and both the header
5045 and the data portions of the image are secured against corruption by
5052 Although U-Boot should support any OS or standalone application
5053 easily, the main focus has always been on Linux during the design of
5056 U-Boot includes many features that so far have been part of some
5057 special "boot loader" code within the Linux kernel. Also, any
5058 "initrd" images to be used are no longer part of one big Linux image;
5059 instead, kernel and "initrd" are separate images. This implementation
5060 serves several purposes:
5062 - the same features can be used for other OS or standalone
5063 applications (for instance: using compressed images to reduce the
5064 Flash memory footprint)
5066 - it becomes much easier to port new Linux kernel versions because
5067 lots of low-level, hardware dependent stuff are done by U-Boot
5069 - the same Linux kernel image can now be used with different "initrd"
5070 images; of course this also means that different kernel images can
5071 be run with the same "initrd". This makes testing easier (you don't
5072 have to build a new "zImage.initrd" Linux image when you just
5073 change a file in your "initrd"). Also, a field-upgrade of the
5074 software is easier now.
5080 Porting Linux to U-Boot based systems:
5081 ---------------------------------------
5083 U-Boot cannot save you from doing all the necessary modifications to
5084 configure the Linux device drivers for use with your target hardware
5085 (no, we don't intend to provide a full virtual machine interface to
5088 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5090 Just make sure your machine specific header file (for instance
5091 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5092 Information structure as we define in include/asm-<arch>/u-boot.h,
5093 and make sure that your definition of IMAP_ADDR uses the same value
5094 as your U-Boot configuration in CONFIG_SYS_IMMR.
5097 Configuring the Linux kernel:
5098 -----------------------------
5100 No specific requirements for U-Boot. Make sure you have some root
5101 device (initial ramdisk, NFS) for your target system.
5104 Building a Linux Image:
5105 -----------------------
5107 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5108 not used. If you use recent kernel source, a new build target
5109 "uImage" will exist which automatically builds an image usable by
5110 U-Boot. Most older kernels also have support for a "pImage" target,
5111 which was introduced for our predecessor project PPCBoot and uses a
5112 100% compatible format.
5121 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5122 encapsulate a compressed Linux kernel image with header information,
5123 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5125 * build a standard "vmlinux" kernel image (in ELF binary format):
5127 * convert the kernel into a raw binary image:
5129 ${CROSS_COMPILE}-objcopy -O binary \
5130 -R .note -R .comment \
5131 -S vmlinux linux.bin
5133 * compress the binary image:
5137 * package compressed binary image for U-Boot:
5139 mkimage -A ppc -O linux -T kernel -C gzip \
5140 -a 0 -e 0 -n "Linux Kernel Image" \
5141 -d linux.bin.gz uImage
5144 The "mkimage" tool can also be used to create ramdisk images for use
5145 with U-Boot, either separated from the Linux kernel image, or
5146 combined into one file. "mkimage" encapsulates the images with a 64
5147 byte header containing information about target architecture,
5148 operating system, image type, compression method, entry points, time
5149 stamp, CRC32 checksums, etc.
5151 "mkimage" can be called in two ways: to verify existing images and
5152 print the header information, or to build new images.
5154 In the first form (with "-l" option) mkimage lists the information
5155 contained in the header of an existing U-Boot image; this includes
5156 checksum verification:
5158 tools/mkimage -l image
5159 -l ==> list image header information
5161 The second form (with "-d" option) is used to build a U-Boot image
5162 from a "data file" which is used as image payload:
5164 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5165 -n name -d data_file image
5166 -A ==> set architecture to 'arch'
5167 -O ==> set operating system to 'os'
5168 -T ==> set image type to 'type'
5169 -C ==> set compression type 'comp'
5170 -a ==> set load address to 'addr' (hex)
5171 -e ==> set entry point to 'ep' (hex)
5172 -n ==> set image name to 'name'
5173 -d ==> use image data from 'datafile'
5175 Right now, all Linux kernels for PowerPC systems use the same load
5176 address (0x00000000), but the entry point address depends on the
5179 - 2.2.x kernels have the entry point at 0x0000000C,
5180 - 2.3.x and later kernels have the entry point at 0x00000000.
5182 So a typical call to build a U-Boot image would read:
5184 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5185 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5186 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5187 > examples/uImage.TQM850L
5188 Image Name: 2.4.4 kernel for TQM850L
5189 Created: Wed Jul 19 02:34:59 2000
5190 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5191 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5192 Load Address: 0x00000000
5193 Entry Point: 0x00000000
5195 To verify the contents of the image (or check for corruption):
5197 -> tools/mkimage -l examples/uImage.TQM850L
5198 Image Name: 2.4.4 kernel for TQM850L
5199 Created: Wed Jul 19 02:34:59 2000
5200 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5201 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5202 Load Address: 0x00000000
5203 Entry Point: 0x00000000
5205 NOTE: for embedded systems where boot time is critical you can trade
5206 speed for memory and install an UNCOMPRESSED image instead: this
5207 needs more space in Flash, but boots much faster since it does not
5208 need to be uncompressed:
5210 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5211 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5212 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5213 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5214 > examples/uImage.TQM850L-uncompressed
5215 Image Name: 2.4.4 kernel for TQM850L
5216 Created: Wed Jul 19 02:34:59 2000
5217 Image Type: PowerPC Linux Kernel Image (uncompressed)
5218 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5219 Load Address: 0x00000000
5220 Entry Point: 0x00000000
5223 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5224 when your kernel is intended to use an initial ramdisk:
5226 -> tools/mkimage -n 'Simple Ramdisk Image' \
5227 > -A ppc -O linux -T ramdisk -C gzip \
5228 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5229 Image Name: Simple Ramdisk Image
5230 Created: Wed Jan 12 14:01:50 2000
5231 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5232 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5233 Load Address: 0x00000000
5234 Entry Point: 0x00000000
5237 Installing a Linux Image:
5238 -------------------------
5240 To downloading a U-Boot image over the serial (console) interface,
5241 you must convert the image to S-Record format:
5243 objcopy -I binary -O srec examples/image examples/image.srec
5245 The 'objcopy' does not understand the information in the U-Boot
5246 image header, so the resulting S-Record file will be relative to
5247 address 0x00000000. To load it to a given address, you need to
5248 specify the target address as 'offset' parameter with the 'loads'
5251 Example: install the image to address 0x40100000 (which on the
5252 TQM8xxL is in the first Flash bank):
5254 => erase 40100000 401FFFFF
5260 ## Ready for S-Record download ...
5261 ~>examples/image.srec
5262 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5264 15989 15990 15991 15992
5265 [file transfer complete]
5267 ## Start Addr = 0x00000000
5270 You can check the success of the download using the 'iminfo' command;
5271 this includes a checksum verification so you can be sure no data
5272 corruption happened:
5276 ## Checking Image at 40100000 ...
5277 Image Name: 2.2.13 for initrd on TQM850L
5278 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5279 Data Size: 335725 Bytes = 327 kB = 0 MB
5280 Load Address: 00000000
5281 Entry Point: 0000000c
5282 Verifying Checksum ... OK
5288 The "bootm" command is used to boot an application that is stored in
5289 memory (RAM or Flash). In case of a Linux kernel image, the contents
5290 of the "bootargs" environment variable is passed to the kernel as
5291 parameters. You can check and modify this variable using the
5292 "printenv" and "setenv" commands:
5295 => printenv bootargs
5296 bootargs=root=/dev/ram
5298 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5300 => printenv bootargs
5301 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5304 ## Booting Linux kernel at 40020000 ...
5305 Image Name: 2.2.13 for NFS on TQM850L
5306 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5307 Data Size: 381681 Bytes = 372 kB = 0 MB
5308 Load Address: 00000000
5309 Entry Point: 0000000c
5310 Verifying Checksum ... OK
5311 Uncompressing Kernel Image ... OK
5312 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
5313 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5314 time_init: decrementer frequency = 187500000/60
5315 Calibrating delay loop... 49.77 BogoMIPS
5316 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5319 If you want to boot a Linux kernel with initial RAM disk, you pass
5320 the memory addresses of both the kernel and the initrd image (PPBCOOT
5321 format!) to the "bootm" command:
5323 => imi 40100000 40200000
5325 ## Checking Image at 40100000 ...
5326 Image Name: 2.2.13 for initrd on TQM850L
5327 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5328 Data Size: 335725 Bytes = 327 kB = 0 MB
5329 Load Address: 00000000
5330 Entry Point: 0000000c
5331 Verifying Checksum ... OK
5333 ## Checking Image at 40200000 ...
5334 Image Name: Simple Ramdisk Image
5335 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5336 Data Size: 566530 Bytes = 553 kB = 0 MB
5337 Load Address: 00000000
5338 Entry Point: 00000000
5339 Verifying Checksum ... OK
5341 => bootm 40100000 40200000
5342 ## Booting Linux kernel at 40100000 ...
5343 Image Name: 2.2.13 for initrd on TQM850L
5344 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5345 Data Size: 335725 Bytes = 327 kB = 0 MB
5346 Load Address: 00000000
5347 Entry Point: 0000000c
5348 Verifying Checksum ... OK
5349 Uncompressing Kernel Image ... OK
5350 ## Loading RAMDisk Image at 40200000 ...
5351 Image Name: Simple Ramdisk Image
5352 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5353 Data Size: 566530 Bytes = 553 kB = 0 MB
5354 Load Address: 00000000
5355 Entry Point: 00000000
5356 Verifying Checksum ... OK
5357 Loading Ramdisk ... OK
5358 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
5359 Boot arguments: root=/dev/ram
5360 time_init: decrementer frequency = 187500000/60
5361 Calibrating delay loop... 49.77 BogoMIPS
5363 RAMDISK: Compressed image found at block 0
5364 VFS: Mounted root (ext2 filesystem).
5368 Boot Linux and pass a flat device tree:
5371 First, U-Boot must be compiled with the appropriate defines. See the section
5372 titled "Linux Kernel Interface" above for a more in depth explanation. The
5373 following is an example of how to start a kernel and pass an updated
5379 oft=oftrees/mpc8540ads.dtb
5380 => tftp $oftaddr $oft
5381 Speed: 1000, full duplex
5383 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5384 Filename 'oftrees/mpc8540ads.dtb'.
5385 Load address: 0x300000
5388 Bytes transferred = 4106 (100a hex)
5389 => tftp $loadaddr $bootfile
5390 Speed: 1000, full duplex
5392 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5394 Load address: 0x200000
5395 Loading:############
5397 Bytes transferred = 1029407 (fb51f hex)
5402 => bootm $loadaddr - $oftaddr
5403 ## Booting image at 00200000 ...
5404 Image Name: Linux-2.6.17-dirty
5405 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5406 Data Size: 1029343 Bytes = 1005.2 kB
5407 Load Address: 00000000
5408 Entry Point: 00000000
5409 Verifying Checksum ... OK
5410 Uncompressing Kernel Image ... OK
5411 Booting using flat device tree at 0x300000
5412 Using MPC85xx ADS machine description
5413 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5417 More About U-Boot Image Types:
5418 ------------------------------
5420 U-Boot supports the following image types:
5422 "Standalone Programs" are directly runnable in the environment
5423 provided by U-Boot; it is expected that (if they behave
5424 well) you can continue to work in U-Boot after return from
5425 the Standalone Program.
5426 "OS Kernel Images" are usually images of some Embedded OS which
5427 will take over control completely. Usually these programs
5428 will install their own set of exception handlers, device
5429 drivers, set up the MMU, etc. - this means, that you cannot
5430 expect to re-enter U-Boot except by resetting the CPU.
5431 "RAMDisk Images" are more or less just data blocks, and their
5432 parameters (address, size) are passed to an OS kernel that is
5434 "Multi-File Images" contain several images, typically an OS
5435 (Linux) kernel image and one or more data images like
5436 RAMDisks. This construct is useful for instance when you want
5437 to boot over the network using BOOTP etc., where the boot
5438 server provides just a single image file, but you want to get
5439 for instance an OS kernel and a RAMDisk image.
5441 "Multi-File Images" start with a list of image sizes, each
5442 image size (in bytes) specified by an "uint32_t" in network
5443 byte order. This list is terminated by an "(uint32_t)0".
5444 Immediately after the terminating 0 follow the images, one by
5445 one, all aligned on "uint32_t" boundaries (size rounded up to
5446 a multiple of 4 bytes).
5448 "Firmware Images" are binary images containing firmware (like
5449 U-Boot or FPGA images) which usually will be programmed to
5452 "Script files" are command sequences that will be executed by
5453 U-Boot's command interpreter; this feature is especially
5454 useful when you configure U-Boot to use a real shell (hush)
5455 as command interpreter.
5457 Booting the Linux zImage:
5458 -------------------------
5460 On some platforms, it's possible to boot Linux zImage. This is done
5461 using the "bootz" command. The syntax of "bootz" command is the same
5462 as the syntax of "bootm" command.
5464 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5465 kernel with raw initrd images. The syntax is slightly different, the
5466 address of the initrd must be augmented by it's size, in the following
5467 format: "<initrd addres>:<initrd size>".
5473 One of the features of U-Boot is that you can dynamically load and
5474 run "standalone" applications, which can use some resources of
5475 U-Boot like console I/O functions or interrupt services.
5477 Two simple examples are included with the sources:
5482 'examples/hello_world.c' contains a small "Hello World" Demo
5483 application; it is automatically compiled when you build U-Boot.
5484 It's configured to run at address 0x00040004, so you can play with it
5488 ## Ready for S-Record download ...
5489 ~>examples/hello_world.srec
5490 1 2 3 4 5 6 7 8 9 10 11 ...
5491 [file transfer complete]
5493 ## Start Addr = 0x00040004
5495 => go 40004 Hello World! This is a test.
5496 ## Starting application at 0x00040004 ...
5507 Hit any key to exit ...
5509 ## Application terminated, rc = 0x0
5511 Another example, which demonstrates how to register a CPM interrupt
5512 handler with the U-Boot code, can be found in 'examples/timer.c'.
5513 Here, a CPM timer is set up to generate an interrupt every second.
5514 The interrupt service routine is trivial, just printing a '.'
5515 character, but this is just a demo program. The application can be
5516 controlled by the following keys:
5518 ? - print current values og the CPM Timer registers
5519 b - enable interrupts and start timer
5520 e - stop timer and disable interrupts
5521 q - quit application
5524 ## Ready for S-Record download ...
5525 ~>examples/timer.srec
5526 1 2 3 4 5 6 7 8 9 10 11 ...
5527 [file transfer complete]
5529 ## Start Addr = 0x00040004
5532 ## Starting application at 0x00040004 ...
5535 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5538 [q, b, e, ?] Set interval 1000000 us
5541 [q, b, e, ?] ........
5542 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5545 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5548 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5551 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5553 [q, b, e, ?] ...Stopping timer
5555 [q, b, e, ?] ## Application terminated, rc = 0x0
5561 Over time, many people have reported problems when trying to use the
5562 "minicom" terminal emulation program for serial download. I (wd)
5563 consider minicom to be broken, and recommend not to use it. Under
5564 Unix, I recommend to use C-Kermit for general purpose use (and
5565 especially for kermit binary protocol download ("loadb" command), and
5566 use "cu" for S-Record download ("loads" command). See
5567 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5568 for help with kermit.
5571 Nevertheless, if you absolutely want to use it try adding this
5572 configuration to your "File transfer protocols" section:
5574 Name Program Name U/D FullScr IO-Red. Multi
5575 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5576 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5582 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5583 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5585 Building requires a cross environment; it is known to work on
5586 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5587 need gmake since the Makefiles are not compatible with BSD make).
5588 Note that the cross-powerpc package does not install include files;
5589 attempting to build U-Boot will fail because <machine/ansi.h> is
5590 missing. This file has to be installed and patched manually:
5592 # cd /usr/pkg/cross/powerpc-netbsd/include
5594 # ln -s powerpc machine
5595 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5596 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5598 Native builds *don't* work due to incompatibilities between native
5599 and U-Boot include files.
5601 Booting assumes that (the first part of) the image booted is a
5602 stage-2 loader which in turn loads and then invokes the kernel
5603 proper. Loader sources will eventually appear in the NetBSD source
5604 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5605 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5608 Implementation Internals:
5609 =========================
5611 The following is not intended to be a complete description of every
5612 implementation detail. However, it should help to understand the
5613 inner workings of U-Boot and make it easier to port it to custom
5617 Initial Stack, Global Data:
5618 ---------------------------
5620 The implementation of U-Boot is complicated by the fact that U-Boot
5621 starts running out of ROM (flash memory), usually without access to
5622 system RAM (because the memory controller is not initialized yet).
5623 This means that we don't have writable Data or BSS segments, and BSS
5624 is not initialized as zero. To be able to get a C environment working
5625 at all, we have to allocate at least a minimal stack. Implementation
5626 options for this are defined and restricted by the CPU used: Some CPU
5627 models provide on-chip memory (like the IMMR area on MPC8xx and
5628 MPC826x processors), on others (parts of) the data cache can be
5629 locked as (mis-) used as memory, etc.
5631 Chris Hallinan posted a good summary of these issues to the
5632 U-Boot mailing list:
5634 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5635 From: "Chris Hallinan" <clh@net1plus.com>
5636 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5639 Correct me if I'm wrong, folks, but the way I understand it
5640 is this: Using DCACHE as initial RAM for Stack, etc, does not
5641 require any physical RAM backing up the cache. The cleverness
5642 is that the cache is being used as a temporary supply of
5643 necessary storage before the SDRAM controller is setup. It's
5644 beyond the scope of this list to explain the details, but you
5645 can see how this works by studying the cache architecture and
5646 operation in the architecture and processor-specific manuals.
5648 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5649 is another option for the system designer to use as an
5650 initial stack/RAM area prior to SDRAM being available. Either
5651 option should work for you. Using CS 4 should be fine if your
5652 board designers haven't used it for something that would
5653 cause you grief during the initial boot! It is frequently not
5656 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5657 with your processor/board/system design. The default value
5658 you will find in any recent u-boot distribution in
5659 walnut.h should work for you. I'd set it to a value larger
5660 than your SDRAM module. If you have a 64MB SDRAM module, set
5661 it above 400_0000. Just make sure your board has no resources
5662 that are supposed to respond to that address! That code in
5663 start.S has been around a while and should work as is when
5664 you get the config right.
5669 It is essential to remember this, since it has some impact on the C
5670 code for the initialization procedures:
5672 * Initialized global data (data segment) is read-only. Do not attempt
5675 * Do not use any uninitialized global data (or implicitely initialized
5676 as zero data - BSS segment) at all - this is undefined, initiali-
5677 zation is performed later (when relocating to RAM).
5679 * Stack space is very limited. Avoid big data buffers or things like
5682 Having only the stack as writable memory limits means we cannot use
5683 normal global data to share information beween the code. But it
5684 turned out that the implementation of U-Boot can be greatly
5685 simplified by making a global data structure (gd_t) available to all
5686 functions. We could pass a pointer to this data as argument to _all_
5687 functions, but this would bloat the code. Instead we use a feature of
5688 the GCC compiler (Global Register Variables) to share the data: we
5689 place a pointer (gd) to the global data into a register which we
5690 reserve for this purpose.
5692 When choosing a register for such a purpose we are restricted by the
5693 relevant (E)ABI specifications for the current architecture, and by
5694 GCC's implementation.
5696 For PowerPC, the following registers have specific use:
5698 R2: reserved for system use
5699 R3-R4: parameter passing and return values
5700 R5-R10: parameter passing
5701 R13: small data area pointer
5705 (U-Boot also uses R12 as internal GOT pointer. r12
5706 is a volatile register so r12 needs to be reset when
5707 going back and forth between asm and C)
5709 ==> U-Boot will use R2 to hold a pointer to the global data
5711 Note: on PPC, we could use a static initializer (since the
5712 address of the global data structure is known at compile time),
5713 but it turned out that reserving a register results in somewhat
5714 smaller code - although the code savings are not that big (on
5715 average for all boards 752 bytes for the whole U-Boot image,
5716 624 text + 127 data).
5718 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5719 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5721 ==> U-Boot will use P3 to hold a pointer to the global data
5723 On ARM, the following registers are used:
5725 R0: function argument word/integer result
5726 R1-R3: function argument word
5727 R9: platform specific
5728 R10: stack limit (used only if stack checking is enabled)
5729 R11: argument (frame) pointer
5730 R12: temporary workspace
5733 R15: program counter
5735 ==> U-Boot will use R9 to hold a pointer to the global data
5737 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5739 On Nios II, the ABI is documented here:
5740 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5742 ==> U-Boot will use gp to hold a pointer to the global data
5744 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5745 to access small data sections, so gp is free.
5747 On NDS32, the following registers are used:
5749 R0-R1: argument/return
5751 R15: temporary register for assembler
5752 R16: trampoline register
5753 R28: frame pointer (FP)
5754 R29: global pointer (GP)
5755 R30: link register (LP)
5756 R31: stack pointer (SP)
5757 PC: program counter (PC)
5759 ==> U-Boot will use R10 to hold a pointer to the global data
5761 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5762 or current versions of GCC may "optimize" the code too much.
5767 U-Boot runs in system state and uses physical addresses, i.e. the
5768 MMU is not used either for address mapping nor for memory protection.
5770 The available memory is mapped to fixed addresses using the memory
5771 controller. In this process, a contiguous block is formed for each
5772 memory type (Flash, SDRAM, SRAM), even when it consists of several
5773 physical memory banks.
5775 U-Boot is installed in the first 128 kB of the first Flash bank (on
5776 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5777 booting and sizing and initializing DRAM, the code relocates itself
5778 to the upper end of DRAM. Immediately below the U-Boot code some
5779 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5780 configuration setting]. Below that, a structure with global Board
5781 Info data is placed, followed by the stack (growing downward).
5783 Additionally, some exception handler code is copied to the low 8 kB
5784 of DRAM (0x00000000 ... 0x00001FFF).
5786 So a typical memory configuration with 16 MB of DRAM could look like
5789 0x0000 0000 Exception Vector code
5792 0x0000 2000 Free for Application Use
5798 0x00FB FF20 Monitor Stack (Growing downward)
5799 0x00FB FFAC Board Info Data and permanent copy of global data
5800 0x00FC 0000 Malloc Arena
5803 0x00FE 0000 RAM Copy of Monitor Code
5804 ... eventually: LCD or video framebuffer
5805 ... eventually: pRAM (Protected RAM - unchanged by reset)
5806 0x00FF FFFF [End of RAM]
5809 System Initialization:
5810 ----------------------
5812 In the reset configuration, U-Boot starts at the reset entry point
5813 (on most PowerPC systems at address 0x00000100). Because of the reset
5814 configuration for CS0# this is a mirror of the onboard Flash memory.
5815 To be able to re-map memory U-Boot then jumps to its link address.
5816 To be able to implement the initialization code in C, a (small!)
5817 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5818 which provide such a feature like MPC8xx or MPC8260), or in a locked
5819 part of the data cache. After that, U-Boot initializes the CPU core,
5820 the caches and the SIU.
5822 Next, all (potentially) available memory banks are mapped using a
5823 preliminary mapping. For example, we put them on 512 MB boundaries
5824 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5825 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5826 programmed for SDRAM access. Using the temporary configuration, a
5827 simple memory test is run that determines the size of the SDRAM
5830 When there is more than one SDRAM bank, and the banks are of
5831 different size, the largest is mapped first. For equal size, the first
5832 bank (CS2#) is mapped first. The first mapping is always for address
5833 0x00000000, with any additional banks following immediately to create
5834 contiguous memory starting from 0.
5836 Then, the monitor installs itself at the upper end of the SDRAM area
5837 and allocates memory for use by malloc() and for the global Board
5838 Info data; also, the exception vector code is copied to the low RAM
5839 pages, and the final stack is set up.
5841 Only after this relocation will you have a "normal" C environment;
5842 until that you are restricted in several ways, mostly because you are
5843 running from ROM, and because the code will have to be relocated to a
5847 U-Boot Porting Guide:
5848 ----------------------
5850 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5854 int main(int argc, char *argv[])
5856 sighandler_t no_more_time;
5858 signal(SIGALRM, no_more_time);
5859 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5861 if (available_money > available_manpower) {
5862 Pay consultant to port U-Boot;
5866 Download latest U-Boot source;
5868 Subscribe to u-boot mailing list;
5871 email("Hi, I am new to U-Boot, how do I get started?");
5874 Read the README file in the top level directory;
5875 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5876 Read applicable doc/*.README;
5877 Read the source, Luke;
5878 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5881 if (available_money > toLocalCurrency ($2500))
5884 Add a lot of aggravation and time;
5886 if (a similar board exists) { /* hopefully... */
5887 cp -a board/<similar> board/<myboard>
5888 cp include/configs/<similar>.h include/configs/<myboard>.h
5890 Create your own board support subdirectory;
5891 Create your own board include/configs/<myboard>.h file;
5893 Edit new board/<myboard> files
5894 Edit new include/configs/<myboard>.h
5899 Add / modify source code;
5903 email("Hi, I am having problems...");
5905 Send patch file to the U-Boot email list;
5906 if (reasonable critiques)
5907 Incorporate improvements from email list code review;
5909 Defend code as written;
5915 void no_more_time (int sig)
5924 All contributions to U-Boot should conform to the Linux kernel
5925 coding style; see the file "Documentation/CodingStyle" and the script
5926 "scripts/Lindent" in your Linux kernel source directory.
5928 Source files originating from a different project (for example the
5929 MTD subsystem) are generally exempt from these guidelines and are not
5930 reformated to ease subsequent migration to newer versions of those
5933 Please note that U-Boot is implemented in C (and to some small parts in
5934 Assembler); no C++ is used, so please do not use C++ style comments (//)
5937 Please also stick to the following formatting rules:
5938 - remove any trailing white space
5939 - use TAB characters for indentation and vertical alignment, not spaces
5940 - make sure NOT to use DOS '\r\n' line feeds
5941 - do not add more than 2 consecutive empty lines to source files
5942 - do not add trailing empty lines to source files
5944 Submissions which do not conform to the standards may be returned
5945 with a request to reformat the changes.
5951 Since the number of patches for U-Boot is growing, we need to
5952 establish some rules. Submissions which do not conform to these rules
5953 may be rejected, even when they contain important and valuable stuff.
5955 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5957 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5958 see http://lists.denx.de/mailman/listinfo/u-boot
5960 When you send a patch, please include the following information with
5963 * For bug fixes: a description of the bug and how your patch fixes
5964 this bug. Please try to include a way of demonstrating that the
5965 patch actually fixes something.
5967 * For new features: a description of the feature and your
5970 * A CHANGELOG entry as plaintext (separate from the patch)
5972 * For major contributions, your entry to the CREDITS file
5974 * When you add support for a new board, don't forget to add a
5975 maintainer e-mail address to the boards.cfg file, too.
5977 * If your patch adds new configuration options, don't forget to
5978 document these in the README file.
5980 * The patch itself. If you are using git (which is *strongly*
5981 recommended) you can easily generate the patch using the
5982 "git format-patch". If you then use "git send-email" to send it to
5983 the U-Boot mailing list, you will avoid most of the common problems
5984 with some other mail clients.
5986 If you cannot use git, use "diff -purN OLD NEW". If your version of
5987 diff does not support these options, then get the latest version of
5990 The current directory when running this command shall be the parent
5991 directory of the U-Boot source tree (i. e. please make sure that
5992 your patch includes sufficient directory information for the
5995 We prefer patches as plain text. MIME attachments are discouraged,
5996 and compressed attachments must not be used.
5998 * If one logical set of modifications affects or creates several
5999 files, all these changes shall be submitted in a SINGLE patch file.
6001 * Changesets that contain different, unrelated modifications shall be
6002 submitted as SEPARATE patches, one patch per changeset.
6007 * Before sending the patch, run the MAKEALL script on your patched
6008 source tree and make sure that no errors or warnings are reported
6009 for any of the boards.
6011 * Keep your modifications to the necessary minimum: A patch
6012 containing several unrelated changes or arbitrary reformats will be
6013 returned with a request to re-formatting / split it.
6015 * If you modify existing code, make sure that your new code does not
6016 add to the memory footprint of the code ;-) Small is beautiful!
6017 When adding new features, these should compile conditionally only
6018 (using #ifdef), and the resulting code with the new feature
6019 disabled must not need more memory than the old code without your
6022 * Remember that there is a size limit of 100 kB per message on the
6023 u-boot mailing list. Bigger patches will be moderated. If they are
6024 reasonable and not too big, they will be acknowledged. But patches
6025 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob