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
822 CONFIG_BOOTCOUNT_LIMIT
823 Implements a mechanism for detecting a repeating reboot
825 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
828 If no softreset save registers are found on the hardware
829 "bootcount" is stored in the environment. To prevent a
830 saveenv on all reboots, the environment variable
831 "upgrade_available" is used. If "upgrade_available" is
832 0, "bootcount" is always 0, if "upgrade_available" is
833 1 "bootcount" is incremented in the environment.
834 So the Userspace Applikation must set the "upgrade_available"
835 and "bootcount" variable to 0, if a boot was successfully.
840 When this option is #defined, the existence of the
841 environment variable "preboot" will be checked
842 immediately before starting the CONFIG_BOOTDELAY
843 countdown and/or running the auto-boot command resp.
844 entering interactive mode.
846 This feature is especially useful when "preboot" is
847 automatically generated or modified. For an example
848 see the LWMON board specific code: here "preboot" is
849 modified when the user holds down a certain
850 combination of keys on the (special) keyboard when
853 - Serial Download Echo Mode:
855 If defined to 1, all characters received during a
856 serial download (using the "loads" command) are
857 echoed back. This might be needed by some terminal
858 emulations (like "cu"), but may as well just take
859 time on others. This setting #define's the initial
860 value of the "loads_echo" environment variable.
862 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
864 Select one of the baudrates listed in
865 CONFIG_SYS_BAUDRATE_TABLE, see below.
868 Monitor commands can be included or excluded
869 from the build by using the #include files
870 <config_cmd_all.h> and #undef'ing unwanted
871 commands, or using <config_cmd_default.h>
872 and augmenting with additional #define's
875 The default command configuration includes all commands
876 except those marked below with a "*".
878 CONFIG_CMD_ASKENV * ask for env variable
879 CONFIG_CMD_BDI bdinfo
880 CONFIG_CMD_BEDBUG * Include BedBug Debugger
881 CONFIG_CMD_BMP * BMP support
882 CONFIG_CMD_BSP * Board specific commands
883 CONFIG_CMD_BOOTD bootd
884 CONFIG_CMD_CACHE * icache, dcache
885 CONFIG_CMD_CONSOLE coninfo
886 CONFIG_CMD_CRC32 * crc32
887 CONFIG_CMD_DATE * support for RTC, date/time...
888 CONFIG_CMD_DHCP * DHCP support
889 CONFIG_CMD_DIAG * Diagnostics
890 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
891 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
892 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
893 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
894 CONFIG_CMD_DTT * Digital Therm and Thermostat
895 CONFIG_CMD_ECHO echo arguments
896 CONFIG_CMD_EDITENV edit env variable
897 CONFIG_CMD_EEPROM * EEPROM read/write support
898 CONFIG_CMD_ELF * bootelf, bootvx
899 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
900 CONFIG_CMD_ENV_FLAGS * display details about env flags
901 CONFIG_CMD_ENV_EXISTS * check existence of env variable
902 CONFIG_CMD_EXPORTENV * export the environment
903 CONFIG_CMD_EXT2 * ext2 command support
904 CONFIG_CMD_EXT4 * ext4 command support
905 CONFIG_CMD_SAVEENV saveenv
906 CONFIG_CMD_FDC * Floppy Disk Support
907 CONFIG_CMD_FAT * FAT command support
908 CONFIG_CMD_FDOS * Dos diskette Support
909 CONFIG_CMD_FLASH flinfo, erase, protect
910 CONFIG_CMD_FPGA FPGA device initialization support
911 CONFIG_CMD_FUSE * Device fuse support
912 CONFIG_CMD_GETTIME * Get time since boot
913 CONFIG_CMD_GO * the 'go' command (exec code)
914 CONFIG_CMD_GREPENV * search environment
915 CONFIG_CMD_HASH * calculate hash / digest
916 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
917 CONFIG_CMD_I2C * I2C serial bus support
918 CONFIG_CMD_IDE * IDE harddisk support
919 CONFIG_CMD_IMI iminfo
920 CONFIG_CMD_IMLS List all images found in NOR flash
921 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
922 CONFIG_CMD_IMMAP * IMMR dump support
923 CONFIG_CMD_IMPORTENV * import an environment
924 CONFIG_CMD_INI * import data from an ini file into the env
925 CONFIG_CMD_IRQ * irqinfo
926 CONFIG_CMD_ITEST Integer/string test of 2 values
927 CONFIG_CMD_JFFS2 * JFFS2 Support
928 CONFIG_CMD_KGDB * kgdb
929 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
930 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
932 CONFIG_CMD_LOADB loadb
933 CONFIG_CMD_LOADS loads
934 CONFIG_CMD_MD5SUM * print md5 message digest
935 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
936 CONFIG_CMD_MEMINFO * Display detailed memory information
937 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
939 CONFIG_CMD_MEMTEST * mtest
940 CONFIG_CMD_MISC Misc functions like sleep etc
941 CONFIG_CMD_MMC * MMC memory mapped support
942 CONFIG_CMD_MII * MII utility commands
943 CONFIG_CMD_MTDPARTS * MTD partition support
944 CONFIG_CMD_NAND * NAND support
945 CONFIG_CMD_NET bootp, tftpboot, rarpboot
946 CONFIG_CMD_NFS NFS support
947 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
948 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
949 CONFIG_CMD_PCI * pciinfo
950 CONFIG_CMD_PCMCIA * PCMCIA support
951 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
953 CONFIG_CMD_PORTIO * Port I/O
954 CONFIG_CMD_READ * Read raw data from partition
955 CONFIG_CMD_REGINFO * Register dump
956 CONFIG_CMD_RUN run command in env variable
957 CONFIG_CMD_SANDBOX * sb command to access sandbox features
958 CONFIG_CMD_SAVES * save S record dump
959 CONFIG_CMD_SCSI * SCSI Support
960 CONFIG_CMD_SDRAM * print SDRAM configuration information
961 (requires CONFIG_CMD_I2C)
962 CONFIG_CMD_SETGETDCR Support for DCR Register access
964 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
965 CONFIG_CMD_SHA1SUM * print sha1 memory digest
966 (requires CONFIG_CMD_MEMORY)
967 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
968 CONFIG_CMD_SOURCE "source" command Support
969 CONFIG_CMD_SPI * SPI serial bus support
970 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
971 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
972 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
973 CONFIG_CMD_TIMER * access to the system tick timer
974 CONFIG_CMD_USB * USB support
975 CONFIG_CMD_CDP * Cisco Discover Protocol support
976 CONFIG_CMD_MFSL * Microblaze FSL support
977 CONFIG_CMD_XIMG Load part of Multi Image
980 EXAMPLE: If you want all functions except of network
981 support you can write:
983 #include "config_cmd_all.h"
984 #undef CONFIG_CMD_NET
987 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
989 Note: Don't enable the "icache" and "dcache" commands
990 (configuration option CONFIG_CMD_CACHE) unless you know
991 what you (and your U-Boot users) are doing. Data
992 cache cannot be enabled on systems like the 8xx or
993 8260 (where accesses to the IMMR region must be
994 uncached), and it cannot be disabled on all other
995 systems where we (mis-) use the data cache to hold an
996 initial stack and some data.
999 XXX - this list needs to get updated!
1001 - Regular expression support:
1003 If this variable is defined, U-Boot is linked against
1004 the SLRE (Super Light Regular Expression) library,
1005 which adds regex support to some commands, as for
1006 example "env grep" and "setexpr".
1010 If this variable is defined, U-Boot will use a device tree
1011 to configure its devices, instead of relying on statically
1012 compiled #defines in the board file. This option is
1013 experimental and only available on a few boards. The device
1014 tree is available in the global data as gd->fdt_blob.
1016 U-Boot needs to get its device tree from somewhere. This can
1017 be done using one of the two options below:
1020 If this variable is defined, U-Boot will embed a device tree
1021 binary in its image. This device tree file should be in the
1022 board directory and called <soc>-<board>.dts. The binary file
1023 is then picked up in board_init_f() and made available through
1024 the global data structure as gd->blob.
1027 If this variable is defined, U-Boot will build a device tree
1028 binary. It will be called u-boot.dtb. Architecture-specific
1029 code will locate it at run-time. Generally this works by:
1031 cat u-boot.bin u-boot.dtb >image.bin
1033 and in fact, U-Boot does this for you, creating a file called
1034 u-boot-dtb.bin which is useful in the common case. You can
1035 still use the individual files if you need something more
1040 If this variable is defined, it enables watchdog
1041 support for the SoC. There must be support in the SoC
1042 specific code for a watchdog. For the 8xx and 8260
1043 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1044 register. When supported for a specific SoC is
1045 available, then no further board specific code should
1046 be needed to use it.
1049 When using a watchdog circuitry external to the used
1050 SoC, then define this variable and provide board
1051 specific code for the "hw_watchdog_reset" function.
1054 CONFIG_VERSION_VARIABLE
1055 If this variable is defined, an environment variable
1056 named "ver" is created by U-Boot showing the U-Boot
1057 version as printed by the "version" command.
1058 Any change to this variable will be reverted at the
1063 When CONFIG_CMD_DATE is selected, the type of the RTC
1064 has to be selected, too. Define exactly one of the
1067 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1068 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1069 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1070 CONFIG_RTC_MC146818 - use MC146818 RTC
1071 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1072 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1073 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1074 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1075 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1076 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1077 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1078 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1081 Note that if the RTC uses I2C, then the I2C interface
1082 must also be configured. See I2C Support, below.
1085 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1087 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1088 chip-ngpio pairs that tell the PCA953X driver the number of
1089 pins supported by a particular chip.
1091 Note that if the GPIO device uses I2C, then the I2C interface
1092 must also be configured. See I2C Support, below.
1094 - Timestamp Support:
1096 When CONFIG_TIMESTAMP is selected, the timestamp
1097 (date and time) of an image is printed by image
1098 commands like bootm or iminfo. This option is
1099 automatically enabled when you select CONFIG_CMD_DATE .
1101 - Partition Labels (disklabels) Supported:
1102 Zero or more of the following:
1103 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1104 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1105 Intel architecture, USB sticks, etc.
1106 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1107 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1108 bootloader. Note 2TB partition limit; see
1110 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1112 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1113 CONFIG_CMD_SCSI) you must configure support for at
1114 least one non-MTD partition type as well.
1117 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1118 board configurations files but used nowhere!
1120 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1121 be performed by calling the function
1122 ide_set_reset(int reset)
1123 which has to be defined in a board specific file
1128 Set this to enable ATAPI support.
1133 Set this to enable support for disks larger than 137GB
1134 Also look at CONFIG_SYS_64BIT_LBA.
1135 Whithout these , LBA48 support uses 32bit variables and will 'only'
1136 support disks up to 2.1TB.
1138 CONFIG_SYS_64BIT_LBA:
1139 When enabled, makes the IDE subsystem use 64bit sector addresses.
1143 At the moment only there is only support for the
1144 SYM53C8XX SCSI controller; define
1145 CONFIG_SCSI_SYM53C8XX to enable it.
1147 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1148 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1149 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1150 maximum numbers of LUNs, SCSI ID's and target
1152 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1154 The environment variable 'scsidevs' is set to the number of
1155 SCSI devices found during the last scan.
1157 - NETWORK Support (PCI):
1159 Support for Intel 8254x/8257x gigabit chips.
1162 Utility code for direct access to the SPI bus on Intel 8257x.
1163 This does not do anything useful unless you set at least one
1164 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1166 CONFIG_E1000_SPI_GENERIC
1167 Allow generic access to the SPI bus on the Intel 8257x, for
1168 example with the "sspi" command.
1171 Management command for E1000 devices. When used on devices
1172 with SPI support you can reprogram the EEPROM from U-Boot.
1174 CONFIG_E1000_FALLBACK_MAC
1175 default MAC for empty EEPROM after production.
1178 Support for Intel 82557/82559/82559ER chips.
1179 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1180 write routine for first time initialisation.
1183 Support for Digital 2114x chips.
1184 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1185 modem chip initialisation (KS8761/QS6611).
1188 Support for National dp83815 chips.
1191 Support for National dp8382[01] gigabit chips.
1193 - NETWORK Support (other):
1195 CONFIG_DRIVER_AT91EMAC
1196 Support for AT91RM9200 EMAC.
1199 Define this to use reduced MII inteface
1201 CONFIG_DRIVER_AT91EMAC_QUIET
1202 If this defined, the driver is quiet.
1203 The driver doen't show link status messages.
1205 CONFIG_CALXEDA_XGMAC
1206 Support for the Calxeda XGMAC device
1209 Support for SMSC's LAN91C96 chips.
1211 CONFIG_LAN91C96_BASE
1212 Define this to hold the physical address
1213 of the LAN91C96's I/O space
1215 CONFIG_LAN91C96_USE_32_BIT
1216 Define this to enable 32 bit addressing
1219 Support for SMSC's LAN91C111 chip
1221 CONFIG_SMC91111_BASE
1222 Define this to hold the physical address
1223 of the device (I/O space)
1225 CONFIG_SMC_USE_32_BIT
1226 Define this if data bus is 32 bits
1228 CONFIG_SMC_USE_IOFUNCS
1229 Define this to use i/o functions instead of macros
1230 (some hardware wont work with macros)
1232 CONFIG_DRIVER_TI_EMAC
1233 Support for davinci emac
1235 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1236 Define this if you have more then 3 PHYs.
1239 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1241 CONFIG_FTGMAC100_EGIGA
1242 Define this to use GE link update with gigabit PHY.
1243 Define this if FTGMAC100 is connected to gigabit PHY.
1244 If your system has 10/100 PHY only, it might not occur
1245 wrong behavior. Because PHY usually return timeout or
1246 useless data when polling gigabit status and gigabit
1247 control registers. This behavior won't affect the
1248 correctnessof 10/100 link speed update.
1251 Support for SMSC's LAN911x and LAN921x chips
1254 Define this to hold the physical address
1255 of the device (I/O space)
1257 CONFIG_SMC911X_32_BIT
1258 Define this if data bus is 32 bits
1260 CONFIG_SMC911X_16_BIT
1261 Define this if data bus is 16 bits. If your processor
1262 automatically converts one 32 bit word to two 16 bit
1263 words you may also try CONFIG_SMC911X_32_BIT.
1266 Support for Renesas on-chip Ethernet controller
1268 CONFIG_SH_ETHER_USE_PORT
1269 Define the number of ports to be used
1271 CONFIG_SH_ETHER_PHY_ADDR
1272 Define the ETH PHY's address
1274 CONFIG_SH_ETHER_CACHE_WRITEBACK
1275 If this option is set, the driver enables cache flush.
1279 Support TPM devices.
1282 Support for i2c bus TPM devices. Only one device
1283 per system is supported at this time.
1285 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1286 Define the the i2c bus number for the TPM device
1288 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1289 Define the TPM's address on the i2c bus
1291 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1292 Define the burst count bytes upper limit
1294 CONFIG_TPM_ATMEL_TWI
1295 Support for Atmel TWI TPM device. Requires I2C support.
1298 Support for generic parallel port TPM devices. Only one device
1299 per system is supported at this time.
1301 CONFIG_TPM_TIS_BASE_ADDRESS
1302 Base address where the generic TPM device is mapped
1303 to. Contemporary x86 systems usually map it at
1307 Add tpm monitor functions.
1308 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1309 provides monitor access to authorized functions.
1312 Define this to enable the TPM support library which provides
1313 functional interfaces to some TPM commands.
1314 Requires support for a TPM device.
1316 CONFIG_TPM_AUTH_SESSIONS
1317 Define this to enable authorized functions in the TPM library.
1318 Requires CONFIG_TPM and CONFIG_SHA1.
1321 At the moment only the UHCI host controller is
1322 supported (PIP405, MIP405, MPC5200); define
1323 CONFIG_USB_UHCI to enable it.
1324 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1325 and define CONFIG_USB_STORAGE to enable the USB
1328 Supported are USB Keyboards and USB Floppy drives
1330 MPC5200 USB requires additional defines:
1332 for 528 MHz Clock: 0x0001bbbb
1336 for differential drivers: 0x00001000
1337 for single ended drivers: 0x00005000
1338 for differential drivers on PSC3: 0x00000100
1339 for single ended drivers on PSC3: 0x00004100
1340 CONFIG_SYS_USB_EVENT_POLL
1341 May be defined to allow interrupt polling
1342 instead of using asynchronous interrupts
1344 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1345 txfilltuning field in the EHCI controller on reset.
1347 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1348 interval for usb hub power-on delay.(minimum 100msec)
1351 Define the below if you wish to use the USB console.
1352 Once firmware is rebuilt from a serial console issue the
1353 command "setenv stdin usbtty; setenv stdout usbtty" and
1354 attach your USB cable. The Unix command "dmesg" should print
1355 it has found a new device. The environment variable usbtty
1356 can be set to gserial or cdc_acm to enable your device to
1357 appear to a USB host as a Linux gserial device or a
1358 Common Device Class Abstract Control Model serial device.
1359 If you select usbtty = gserial you should be able to enumerate
1361 # modprobe usbserial vendor=0xVendorID product=0xProductID
1362 else if using cdc_acm, simply setting the environment
1363 variable usbtty to be cdc_acm should suffice. The following
1364 might be defined in YourBoardName.h
1367 Define this to build a UDC device
1370 Define this to have a tty type of device available to
1371 talk to the UDC device
1374 Define this to enable the high speed support for usb
1375 device and usbtty. If this feature is enabled, a routine
1376 int is_usbd_high_speed(void)
1377 also needs to be defined by the driver to dynamically poll
1378 whether the enumeration has succeded at high speed or full
1381 CONFIG_SYS_CONSOLE_IS_IN_ENV
1382 Define this if you want stdin, stdout &/or stderr to
1386 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1387 Derive USB clock from external clock "blah"
1388 - CONFIG_SYS_USB_EXTC_CLK 0x02
1390 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1391 Derive USB clock from brgclk
1392 - CONFIG_SYS_USB_BRG_CLK 0x04
1394 If you have a USB-IF assigned VendorID then you may wish to
1395 define your own vendor specific values either in BoardName.h
1396 or directly in usbd_vendor_info.h. If you don't define
1397 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1398 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1399 should pretend to be a Linux device to it's target host.
1401 CONFIG_USBD_MANUFACTURER
1402 Define this string as the name of your company for
1403 - CONFIG_USBD_MANUFACTURER "my company"
1405 CONFIG_USBD_PRODUCT_NAME
1406 Define this string as the name of your product
1407 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1409 CONFIG_USBD_VENDORID
1410 Define this as your assigned Vendor ID from the USB
1411 Implementors Forum. This *must* be a genuine Vendor ID
1412 to avoid polluting the USB namespace.
1413 - CONFIG_USBD_VENDORID 0xFFFF
1415 CONFIG_USBD_PRODUCTID
1416 Define this as the unique Product ID
1418 - CONFIG_USBD_PRODUCTID 0xFFFF
1420 Some USB device drivers may need to check USB cable attachment.
1421 In this case you can enable following config in BoardName.h:
1422 CONFIG_USB_CABLE_CHECK
1423 This enables function definition:
1424 - usb_cable_connected() in include/usb.h
1425 Implementation of this function is board-specific.
1427 - ULPI Layer Support:
1428 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1429 the generic ULPI layer. The generic layer accesses the ULPI PHY
1430 via the platform viewport, so you need both the genric layer and
1431 the viewport enabled. Currently only Chipidea/ARC based
1432 viewport is supported.
1433 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1434 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1435 If your ULPI phy needs a different reference clock than the
1436 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1437 the appropriate value in Hz.
1440 The MMC controller on the Intel PXA is supported. To
1441 enable this define CONFIG_MMC. The MMC can be
1442 accessed from the boot prompt by mapping the device
1443 to physical memory similar to flash. Command line is
1444 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1445 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1448 Support for Renesas on-chip MMCIF controller
1450 CONFIG_SH_MMCIF_ADDR
1451 Define the base address of MMCIF registers
1454 Define the clock frequency for MMCIF
1456 - USB Device Firmware Update (DFU) class support:
1458 This enables the USB portion of the DFU USB class
1461 This enables the command "dfu" which is used to have
1462 U-Boot create a DFU class device via USB. This command
1463 requires that the "dfu_alt_info" environment variable be
1464 set and define the alt settings to expose to the host.
1467 This enables support for exposing (e)MMC devices via DFU.
1470 This enables support for exposing NAND devices via DFU.
1473 This enables support for exposing RAM via DFU.
1474 Note: DFU spec refer to non-volatile memory usage, but
1475 allow usages beyond the scope of spec - here RAM usage,
1476 one that would help mostly the developer.
1478 CONFIG_SYS_DFU_DATA_BUF_SIZE
1479 Dfu transfer uses a buffer before writing data to the
1480 raw storage device. Make the size (in bytes) of this buffer
1481 configurable. The size of this buffer is also configurable
1482 through the "dfu_bufsiz" environment variable.
1484 CONFIG_SYS_DFU_MAX_FILE_SIZE
1485 When updating files rather than the raw storage device,
1486 we use a static buffer to copy the file into and then write
1487 the buffer once we've been given the whole file. Define
1488 this to the maximum filesize (in bytes) for the buffer.
1489 Default is 4 MiB if undefined.
1491 - Journaling Flash filesystem support:
1492 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1493 CONFIG_JFFS2_NAND_DEV
1494 Define these for a default partition on a NAND device
1496 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1497 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1498 Define these for a default partition on a NOR device
1500 CONFIG_SYS_JFFS_CUSTOM_PART
1501 Define this to create an own partition. You have to provide a
1502 function struct part_info* jffs2_part_info(int part_num)
1504 If you define only one JFFS2 partition you may also want to
1505 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1506 to disable the command chpart. This is the default when you
1507 have not defined a custom partition
1509 - FAT(File Allocation Table) filesystem write function support:
1512 Define this to enable support for saving memory data as a
1513 file in FAT formatted partition.
1515 This will also enable the command "fatwrite" enabling the
1516 user to write files to FAT.
1518 CBFS (Coreboot Filesystem) support
1521 Define this to enable support for reading from a Coreboot
1522 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1528 Define this to enable standard (PC-Style) keyboard
1532 Standard PC keyboard driver with US (is default) and
1533 GERMAN key layout (switch via environment 'keymap=de') support.
1534 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1535 for cfb_console. Supports cursor blinking.
1538 Enables a Chrome OS keyboard using the CROS_EC interface.
1539 This uses CROS_EC to communicate with a second microcontroller
1540 which provides key scans on request.
1545 Define this to enable video support (for output to
1548 CONFIG_VIDEO_CT69000
1550 Enable Chips & Technologies 69000 Video chip
1552 CONFIG_VIDEO_SMI_LYNXEM
1553 Enable Silicon Motion SMI 712/710/810 Video chip. The
1554 video output is selected via environment 'videoout'
1555 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1558 For the CT69000 and SMI_LYNXEM drivers, videomode is
1559 selected via environment 'videomode'. Two different ways
1561 - "videomode=num" 'num' is a standard LiLo mode numbers.
1562 Following standard modes are supported (* is default):
1564 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1565 -------------+---------------------------------------------
1566 8 bits | 0x301* 0x303 0x305 0x161 0x307
1567 15 bits | 0x310 0x313 0x316 0x162 0x319
1568 16 bits | 0x311 0x314 0x317 0x163 0x31A
1569 24 bits | 0x312 0x315 0x318 ? 0x31B
1570 -------------+---------------------------------------------
1571 (i.e. setenv videomode 317; saveenv; reset;)
1573 - "videomode=bootargs" all the video parameters are parsed
1574 from the bootargs. (See drivers/video/videomodes.c)
1577 CONFIG_VIDEO_SED13806
1578 Enable Epson SED13806 driver. This driver supports 8bpp
1579 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1580 or CONFIG_VIDEO_SED13806_16BPP
1583 Enable the Freescale DIU video driver. Reference boards for
1584 SOCs that have a DIU should define this macro to enable DIU
1585 support, and should also define these other macros:
1591 CONFIG_VIDEO_SW_CURSOR
1592 CONFIG_VGA_AS_SINGLE_DEVICE
1594 CONFIG_VIDEO_BMP_LOGO
1596 The DIU driver will look for the 'video-mode' environment
1597 variable, and if defined, enable the DIU as a console during
1598 boot. See the documentation file README.video for a
1599 description of this variable.
1603 Enable the VGA video / BIOS for x86. The alternative if you
1604 are using coreboot is to use the coreboot frame buffer
1611 Define this to enable a custom keyboard support.
1612 This simply calls drv_keyboard_init() which must be
1613 defined in your board-specific files.
1614 The only board using this so far is RBC823.
1616 - LCD Support: CONFIG_LCD
1618 Define this to enable LCD support (for output to LCD
1619 display); also select one of the supported displays
1620 by defining one of these:
1624 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1626 CONFIG_NEC_NL6448AC33:
1628 NEC NL6448AC33-18. Active, color, single scan.
1630 CONFIG_NEC_NL6448BC20
1632 NEC NL6448BC20-08. 6.5", 640x480.
1633 Active, color, single scan.
1635 CONFIG_NEC_NL6448BC33_54
1637 NEC NL6448BC33-54. 10.4", 640x480.
1638 Active, color, single scan.
1642 Sharp 320x240. Active, color, single scan.
1643 It isn't 16x9, and I am not sure what it is.
1645 CONFIG_SHARP_LQ64D341
1647 Sharp LQ64D341 display, 640x480.
1648 Active, color, single scan.
1652 HLD1045 display, 640x480.
1653 Active, color, single scan.
1657 Optrex CBL50840-2 NF-FW 99 22 M5
1659 Hitachi LMG6912RPFC-00T
1663 320x240. Black & white.
1665 Normally display is black on white background; define
1666 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1668 CONFIG_LCD_ALIGNMENT
1670 Normally the LCD is page-aligned (tyically 4KB). If this is
1671 defined then the LCD will be aligned to this value instead.
1672 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1673 here, since it is cheaper to change data cache settings on
1674 a per-section basis.
1676 CONFIG_CONSOLE_SCROLL_LINES
1678 When the console need to be scrolled, this is the number of
1679 lines to scroll by. It defaults to 1. Increasing this makes
1680 the console jump but can help speed up operation when scrolling
1685 Support drawing of RLE8-compressed bitmaps on the LCD.
1689 Enables an 'i2c edid' command which can read EDID
1690 information over I2C from an attached LCD display.
1692 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1694 If this option is set, the environment is checked for
1695 a variable "splashimage". If found, the usual display
1696 of logo, copyright and system information on the LCD
1697 is suppressed and the BMP image at the address
1698 specified in "splashimage" is loaded instead. The
1699 console is redirected to the "nulldev", too. This
1700 allows for a "silent" boot where a splash screen is
1701 loaded very quickly after power-on.
1703 CONFIG_SPLASHIMAGE_GUARD
1705 If this option is set, then U-Boot will prevent the environment
1706 variable "splashimage" from being set to a problematic address
1707 (see README.displaying-bmps and README.arm-unaligned-accesses).
1708 This option is useful for targets where, due to alignment
1709 restrictions, an improperly aligned BMP image will cause a data
1710 abort. If you think you will not have problems with unaligned
1711 accesses (for example because your toolchain prevents them)
1712 there is no need to set this option.
1714 CONFIG_SPLASH_SCREEN_ALIGN
1716 If this option is set the splash image can be freely positioned
1717 on the screen. Environment variable "splashpos" specifies the
1718 position as "x,y". If a positive number is given it is used as
1719 number of pixel from left/top. If a negative number is given it
1720 is used as number of pixel from right/bottom. You can also
1721 specify 'm' for centering the image.
1724 setenv splashpos m,m
1725 => image at center of screen
1727 setenv splashpos 30,20
1728 => image at x = 30 and y = 20
1730 setenv splashpos -10,m
1731 => vertically centered image
1732 at x = dspWidth - bmpWidth - 9
1734 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1736 If this option is set, additionally to standard BMP
1737 images, gzipped BMP images can be displayed via the
1738 splashscreen support or the bmp command.
1740 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1742 If this option is set, 8-bit RLE compressed BMP images
1743 can be displayed via the splashscreen support or the
1746 - Do compresssing for memory range:
1749 If this option is set, it would use zlib deflate method
1750 to compress the specified memory at its best effort.
1752 - Compression support:
1755 Enabled by default to support gzip compressed images.
1759 If this option is set, support for bzip2 compressed
1760 images is included. If not, only uncompressed and gzip
1761 compressed images are supported.
1763 NOTE: the bzip2 algorithm requires a lot of RAM, so
1764 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1769 If this option is set, support for lzma compressed
1772 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1773 requires an amount of dynamic memory that is given by the
1776 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1778 Where lc and lp stand for, respectively, Literal context bits
1779 and Literal pos bits.
1781 This value is upper-bounded by 14MB in the worst case. Anyway,
1782 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1783 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1784 a very small buffer.
1786 Use the lzmainfo tool to determinate the lc and lp values and
1787 then calculate the amount of needed dynamic memory (ensuring
1788 the appropriate CONFIG_SYS_MALLOC_LEN value).
1792 If this option is set, support for LZO compressed images
1798 The address of PHY on MII bus.
1800 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1802 The clock frequency of the MII bus
1806 If this option is set, support for speed/duplex
1807 detection of gigabit PHY is included.
1809 CONFIG_PHY_RESET_DELAY
1811 Some PHY like Intel LXT971A need extra delay after
1812 reset before any MII register access is possible.
1813 For such PHY, set this option to the usec delay
1814 required. (minimum 300usec for LXT971A)
1816 CONFIG_PHY_CMD_DELAY (ppc4xx)
1818 Some PHY like Intel LXT971A need extra delay after
1819 command issued before MII status register can be read
1829 Define a default value for Ethernet address to use
1830 for the respective Ethernet interface, in case this
1831 is not determined automatically.
1836 Define a default value for the IP address to use for
1837 the default Ethernet interface, in case this is not
1838 determined through e.g. bootp.
1839 (Environment variable "ipaddr")
1841 - Server IP address:
1844 Defines a default value for the IP address of a TFTP
1845 server to contact when using the "tftboot" command.
1846 (Environment variable "serverip")
1848 CONFIG_KEEP_SERVERADDR
1850 Keeps the server's MAC address, in the env 'serveraddr'
1851 for passing to bootargs (like Linux's netconsole option)
1853 - Gateway IP address:
1856 Defines a default value for the IP address of the
1857 default router where packets to other networks are
1859 (Environment variable "gatewayip")
1864 Defines a default value for the subnet mask (or
1865 routing prefix) which is used to determine if an IP
1866 address belongs to the local subnet or needs to be
1867 forwarded through a router.
1868 (Environment variable "netmask")
1870 - Multicast TFTP Mode:
1873 Defines whether you want to support multicast TFTP as per
1874 rfc-2090; for example to work with atftp. Lets lots of targets
1875 tftp down the same boot image concurrently. Note: the Ethernet
1876 driver in use must provide a function: mcast() to join/leave a
1879 - BOOTP Recovery Mode:
1880 CONFIG_BOOTP_RANDOM_DELAY
1882 If you have many targets in a network that try to
1883 boot using BOOTP, you may want to avoid that all
1884 systems send out BOOTP requests at precisely the same
1885 moment (which would happen for instance at recovery
1886 from a power failure, when all systems will try to
1887 boot, thus flooding the BOOTP server. Defining
1888 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1889 inserted before sending out BOOTP requests. The
1890 following delays are inserted then:
1892 1st BOOTP request: delay 0 ... 1 sec
1893 2nd BOOTP request: delay 0 ... 2 sec
1894 3rd BOOTP request: delay 0 ... 4 sec
1896 BOOTP requests: delay 0 ... 8 sec
1898 - DHCP Advanced Options:
1899 You can fine tune the DHCP functionality by defining
1900 CONFIG_BOOTP_* symbols:
1902 CONFIG_BOOTP_SUBNETMASK
1903 CONFIG_BOOTP_GATEWAY
1904 CONFIG_BOOTP_HOSTNAME
1905 CONFIG_BOOTP_NISDOMAIN
1906 CONFIG_BOOTP_BOOTPATH
1907 CONFIG_BOOTP_BOOTFILESIZE
1910 CONFIG_BOOTP_SEND_HOSTNAME
1911 CONFIG_BOOTP_NTPSERVER
1912 CONFIG_BOOTP_TIMEOFFSET
1913 CONFIG_BOOTP_VENDOREX
1914 CONFIG_BOOTP_MAY_FAIL
1916 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1917 environment variable, not the BOOTP server.
1919 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1920 after the configured retry count, the call will fail
1921 instead of starting over. This can be used to fail over
1922 to Link-local IP address configuration if the DHCP server
1925 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1926 serverip from a DHCP server, it is possible that more
1927 than one DNS serverip is offered to the client.
1928 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1929 serverip will be stored in the additional environment
1930 variable "dnsip2". The first DNS serverip is always
1931 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1934 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1935 to do a dynamic update of a DNS server. To do this, they
1936 need the hostname of the DHCP requester.
1937 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1938 of the "hostname" environment variable is passed as
1939 option 12 to the DHCP server.
1941 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1943 A 32bit value in microseconds for a delay between
1944 receiving a "DHCP Offer" and sending the "DHCP Request".
1945 This fixes a problem with certain DHCP servers that don't
1946 respond 100% of the time to a "DHCP request". E.g. On an
1947 AT91RM9200 processor running at 180MHz, this delay needed
1948 to be *at least* 15,000 usec before a Windows Server 2003
1949 DHCP server would reply 100% of the time. I recommend at
1950 least 50,000 usec to be safe. The alternative is to hope
1951 that one of the retries will be successful but note that
1952 the DHCP timeout and retry process takes a longer than
1955 - Link-local IP address negotiation:
1956 Negotiate with other link-local clients on the local network
1957 for an address that doesn't require explicit configuration.
1958 This is especially useful if a DHCP server cannot be guaranteed
1959 to exist in all environments that the device must operate.
1961 See doc/README.link-local for more information.
1964 CONFIG_CDP_DEVICE_ID
1966 The device id used in CDP trigger frames.
1968 CONFIG_CDP_DEVICE_ID_PREFIX
1970 A two character string which is prefixed to the MAC address
1975 A printf format string which contains the ascii name of
1976 the port. Normally is set to "eth%d" which sets
1977 eth0 for the first Ethernet, eth1 for the second etc.
1979 CONFIG_CDP_CAPABILITIES
1981 A 32bit integer which indicates the device capabilities;
1982 0x00000010 for a normal host which does not forwards.
1986 An ascii string containing the version of the software.
1990 An ascii string containing the name of the platform.
1994 A 32bit integer sent on the trigger.
1996 CONFIG_CDP_POWER_CONSUMPTION
1998 A 16bit integer containing the power consumption of the
1999 device in .1 of milliwatts.
2001 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2003 A byte containing the id of the VLAN.
2005 - Status LED: CONFIG_STATUS_LED
2007 Several configurations allow to display the current
2008 status using a LED. For instance, the LED will blink
2009 fast while running U-Boot code, stop blinking as
2010 soon as a reply to a BOOTP request was received, and
2011 start blinking slow once the Linux kernel is running
2012 (supported by a status LED driver in the Linux
2013 kernel). Defining CONFIG_STATUS_LED enables this
2019 The status LED can be connected to a GPIO pin.
2020 In such cases, the gpio_led driver can be used as a
2021 status LED backend implementation. Define CONFIG_GPIO_LED
2022 to include the gpio_led driver in the U-Boot binary.
2024 CONFIG_GPIO_LED_INVERTED_TABLE
2025 Some GPIO connected LEDs may have inverted polarity in which
2026 case the GPIO high value corresponds to LED off state and
2027 GPIO low value corresponds to LED on state.
2028 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2029 with a list of GPIO LEDs that have inverted polarity.
2031 - CAN Support: CONFIG_CAN_DRIVER
2033 Defining CONFIG_CAN_DRIVER enables CAN driver support
2034 on those systems that support this (optional)
2035 feature, like the TQM8xxL modules.
2037 - I2C Support: CONFIG_SYS_I2C
2039 This enable the NEW i2c subsystem, and will allow you to use
2040 i2c commands at the u-boot command line (as long as you set
2041 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2042 based realtime clock chips or other i2c devices. See
2043 common/cmd_i2c.c for a description of the command line
2046 ported i2c driver to the new framework:
2047 - drivers/i2c/soft_i2c.c:
2048 - activate first bus with CONFIG_SYS_I2C_SOFT define
2049 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2050 for defining speed and slave address
2051 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2052 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2053 for defining speed and slave address
2054 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2055 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2056 for defining speed and slave address
2057 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2058 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2059 for defining speed and slave address
2061 - drivers/i2c/fsl_i2c.c:
2062 - activate i2c driver with CONFIG_SYS_I2C_FSL
2063 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2064 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2065 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2067 - If your board supports a second fsl i2c bus, define
2068 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2069 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2070 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2073 - drivers/i2c/tegra_i2c.c:
2074 - activate this driver with CONFIG_SYS_I2C_TEGRA
2075 - This driver adds 4 i2c buses with a fix speed from
2076 100000 and the slave addr 0!
2078 - drivers/i2c/ppc4xx_i2c.c
2079 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2080 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2081 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2083 - drivers/i2c/i2c_mxc.c
2084 - activate this driver with CONFIG_SYS_I2C_MXC
2085 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2086 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2087 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2088 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2089 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2090 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2091 If thoses defines are not set, default value is 100000
2092 for speed, and 0 for slave.
2094 - drivers/i2c/rcar_i2c.c:
2095 - activate this driver with CONFIG_SYS_I2C_RCAR
2096 - This driver adds 4 i2c buses
2098 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2099 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2100 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2101 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2102 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2103 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2104 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2105 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2106 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2108 - drivers/i2c/sh_i2c.c:
2109 - activate this driver with CONFIG_SYS_I2C_SH
2110 - This driver adds from 2 to 5 i2c buses
2112 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2113 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2114 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2115 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2116 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2117 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2118 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2119 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2120 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2121 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2122 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2123 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2124 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2126 - drivers/i2c/omap24xx_i2c.c
2127 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2128 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2129 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2130 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2131 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2132 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2133 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2134 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2135 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2136 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2137 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2139 - drivers/i2c/zynq_i2c.c
2140 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2141 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2142 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2144 - drivers/i2c/s3c24x0_i2c.c:
2145 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2146 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2147 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2148 with a fix speed from 100000 and the slave addr 0!
2152 CONFIG_SYS_NUM_I2C_BUSES
2153 Hold the number of i2c busses you want to use. If you
2154 don't use/have i2c muxes on your i2c bus, this
2155 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2158 CONFIG_SYS_I2C_DIRECT_BUS
2159 define this, if you don't use i2c muxes on your hardware.
2160 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2163 CONFIG_SYS_I2C_MAX_HOPS
2164 define how many muxes are maximal consecutively connected
2165 on one i2c bus. If you not use i2c muxes, omit this
2168 CONFIG_SYS_I2C_BUSES
2169 hold a list of busses you want to use, only used if
2170 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2171 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2172 CONFIG_SYS_NUM_I2C_BUSES = 9:
2174 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2175 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2176 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2177 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2178 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2179 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2180 {1, {I2C_NULL_HOP}}, \
2181 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2182 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2186 bus 0 on adapter 0 without a mux
2187 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2188 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2189 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2190 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2191 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2192 bus 6 on adapter 1 without a mux
2193 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2194 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2196 If you do not have i2c muxes on your board, omit this define.
2198 - Legacy I2C Support: CONFIG_HARD_I2C
2200 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2201 provides the following compelling advantages:
2203 - more than one i2c adapter is usable
2204 - approved multibus support
2205 - better i2c mux support
2207 ** Please consider updating your I2C driver now. **
2209 These enable legacy I2C serial bus commands. Defining
2210 CONFIG_HARD_I2C will include the appropriate I2C driver
2211 for the selected CPU.
2213 This will allow you to use i2c commands at the u-boot
2214 command line (as long as you set CONFIG_CMD_I2C in
2215 CONFIG_COMMANDS) and communicate with i2c based realtime
2216 clock chips. See common/cmd_i2c.c for a description of the
2217 command line interface.
2219 CONFIG_HARD_I2C selects a hardware I2C controller.
2221 There are several other quantities that must also be
2222 defined when you define CONFIG_HARD_I2C.
2224 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2225 to be the frequency (in Hz) at which you wish your i2c bus
2226 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2227 the CPU's i2c node address).
2229 Now, the u-boot i2c code for the mpc8xx
2230 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2231 and so its address should therefore be cleared to 0 (See,
2232 eg, MPC823e User's Manual p.16-473). So, set
2233 CONFIG_SYS_I2C_SLAVE to 0.
2235 CONFIG_SYS_I2C_INIT_MPC5XXX
2237 When a board is reset during an i2c bus transfer
2238 chips might think that the current transfer is still
2239 in progress. Reset the slave devices by sending start
2240 commands until the slave device responds.
2242 That's all that's required for CONFIG_HARD_I2C.
2244 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2245 then the following macros need to be defined (examples are
2246 from include/configs/lwmon.h):
2250 (Optional). Any commands necessary to enable the I2C
2251 controller or configure ports.
2253 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2257 (Only for MPC8260 CPU). The I/O port to use (the code
2258 assumes both bits are on the same port). Valid values
2259 are 0..3 for ports A..D.
2263 The code necessary to make the I2C data line active
2264 (driven). If the data line is open collector, this
2267 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2271 The code necessary to make the I2C data line tri-stated
2272 (inactive). If the data line is open collector, this
2275 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2279 Code that returns true if the I2C data line is high,
2282 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2286 If <bit> is true, sets the I2C data line high. If it
2287 is false, it clears it (low).
2289 eg: #define I2C_SDA(bit) \
2290 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2291 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2295 If <bit> is true, sets the I2C clock line high. If it
2296 is false, it clears it (low).
2298 eg: #define I2C_SCL(bit) \
2299 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2300 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2304 This delay is invoked four times per clock cycle so this
2305 controls the rate of data transfer. The data rate thus
2306 is 1 / (I2C_DELAY * 4). Often defined to be something
2309 #define I2C_DELAY udelay(2)
2311 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2313 If your arch supports the generic GPIO framework (asm/gpio.h),
2314 then you may alternatively define the two GPIOs that are to be
2315 used as SCL / SDA. Any of the previous I2C_xxx macros will
2316 have GPIO-based defaults assigned to them as appropriate.
2318 You should define these to the GPIO value as given directly to
2319 the generic GPIO functions.
2321 CONFIG_SYS_I2C_INIT_BOARD
2323 When a board is reset during an i2c bus transfer
2324 chips might think that the current transfer is still
2325 in progress. On some boards it is possible to access
2326 the i2c SCLK line directly, either by using the
2327 processor pin as a GPIO or by having a second pin
2328 connected to the bus. If this option is defined a
2329 custom i2c_init_board() routine in boards/xxx/board.c
2330 is run early in the boot sequence.
2332 CONFIG_SYS_I2C_BOARD_LATE_INIT
2334 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2335 defined a custom i2c_board_late_init() routine in
2336 boards/xxx/board.c is run AFTER the operations in i2c_init()
2337 is completed. This callpoint can be used to unreset i2c bus
2338 using CPU i2c controller register accesses for CPUs whose i2c
2339 controller provide such a method. It is called at the end of
2340 i2c_init() to allow i2c_init operations to setup the i2c bus
2341 controller on the CPU (e.g. setting bus speed & slave address).
2343 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2345 This option enables configuration of bi_iic_fast[] flags
2346 in u-boot bd_info structure based on u-boot environment
2347 variable "i2cfast". (see also i2cfast)
2349 CONFIG_I2C_MULTI_BUS
2351 This option allows the use of multiple I2C buses, each of which
2352 must have a controller. At any point in time, only one bus is
2353 active. To switch to a different bus, use the 'i2c dev' command.
2354 Note that bus numbering is zero-based.
2356 CONFIG_SYS_I2C_NOPROBES
2358 This option specifies a list of I2C devices that will be skipped
2359 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2360 is set, specify a list of bus-device pairs. Otherwise, specify
2361 a 1D array of device addresses
2364 #undef CONFIG_I2C_MULTI_BUS
2365 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2367 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2369 #define CONFIG_I2C_MULTI_BUS
2370 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2372 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2374 CONFIG_SYS_SPD_BUS_NUM
2376 If defined, then this indicates the I2C bus number for DDR SPD.
2377 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2379 CONFIG_SYS_RTC_BUS_NUM
2381 If defined, then this indicates the I2C bus number for the RTC.
2382 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2384 CONFIG_SYS_DTT_BUS_NUM
2386 If defined, then this indicates the I2C bus number for the DTT.
2387 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2389 CONFIG_SYS_I2C_DTT_ADDR:
2391 If defined, specifies the I2C address of the DTT device.
2392 If not defined, then U-Boot uses predefined value for
2393 specified DTT device.
2395 CONFIG_SOFT_I2C_READ_REPEATED_START
2397 defining this will force the i2c_read() function in
2398 the soft_i2c driver to perform an I2C repeated start
2399 between writing the address pointer and reading the
2400 data. If this define is omitted the default behaviour
2401 of doing a stop-start sequence will be used. Most I2C
2402 devices can use either method, but some require one or
2405 - SPI Support: CONFIG_SPI
2407 Enables SPI driver (so far only tested with
2408 SPI EEPROM, also an instance works with Crystal A/D and
2409 D/As on the SACSng board)
2413 Enables the driver for SPI controller on SuperH. Currently
2414 only SH7757 is supported.
2418 Enables extended (16-bit) SPI EEPROM addressing.
2419 (symmetrical to CONFIG_I2C_X)
2423 Enables a software (bit-bang) SPI driver rather than
2424 using hardware support. This is a general purpose
2425 driver that only requires three general I/O port pins
2426 (two outputs, one input) to function. If this is
2427 defined, the board configuration must define several
2428 SPI configuration items (port pins to use, etc). For
2429 an example, see include/configs/sacsng.h.
2433 Enables a hardware SPI driver for general-purpose reads
2434 and writes. As with CONFIG_SOFT_SPI, the board configuration
2435 must define a list of chip-select function pointers.
2436 Currently supported on some MPC8xxx processors. For an
2437 example, see include/configs/mpc8349emds.h.
2441 Enables the driver for the SPI controllers on i.MX and MXC
2442 SoCs. Currently i.MX31/35/51 are supported.
2444 - FPGA Support: CONFIG_FPGA
2446 Enables FPGA subsystem.
2448 CONFIG_FPGA_<vendor>
2450 Enables support for specific chip vendors.
2453 CONFIG_FPGA_<family>
2455 Enables support for FPGA family.
2456 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2460 Specify the number of FPGA devices to support.
2462 CONFIG_SYS_FPGA_PROG_FEEDBACK
2464 Enable printing of hash marks during FPGA configuration.
2466 CONFIG_SYS_FPGA_CHECK_BUSY
2468 Enable checks on FPGA configuration interface busy
2469 status by the configuration function. This option
2470 will require a board or device specific function to
2475 If defined, a function that provides delays in the FPGA
2476 configuration driver.
2478 CONFIG_SYS_FPGA_CHECK_CTRLC
2479 Allow Control-C to interrupt FPGA configuration
2481 CONFIG_SYS_FPGA_CHECK_ERROR
2483 Check for configuration errors during FPGA bitfile
2484 loading. For example, abort during Virtex II
2485 configuration if the INIT_B line goes low (which
2486 indicated a CRC error).
2488 CONFIG_SYS_FPGA_WAIT_INIT
2490 Maximum time to wait for the INIT_B line to deassert
2491 after PROB_B has been deasserted during a Virtex II
2492 FPGA configuration sequence. The default time is 500
2495 CONFIG_SYS_FPGA_WAIT_BUSY
2497 Maximum time to wait for BUSY to deassert during
2498 Virtex II FPGA configuration. The default is 5 ms.
2500 CONFIG_SYS_FPGA_WAIT_CONFIG
2502 Time to wait after FPGA configuration. The default is
2505 - Configuration Management:
2508 If defined, this string will be added to the U-Boot
2509 version information (U_BOOT_VERSION)
2511 - Vendor Parameter Protection:
2513 U-Boot considers the values of the environment
2514 variables "serial#" (Board Serial Number) and
2515 "ethaddr" (Ethernet Address) to be parameters that
2516 are set once by the board vendor / manufacturer, and
2517 protects these variables from casual modification by
2518 the user. Once set, these variables are read-only,
2519 and write or delete attempts are rejected. You can
2520 change this behaviour:
2522 If CONFIG_ENV_OVERWRITE is #defined in your config
2523 file, the write protection for vendor parameters is
2524 completely disabled. Anybody can change or delete
2527 Alternatively, if you #define _both_ CONFIG_ETHADDR
2528 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2529 Ethernet address is installed in the environment,
2530 which can be changed exactly ONCE by the user. [The
2531 serial# is unaffected by this, i. e. it remains
2534 The same can be accomplished in a more flexible way
2535 for any variable by configuring the type of access
2536 to allow for those variables in the ".flags" variable
2537 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2542 Define this variable to enable the reservation of
2543 "protected RAM", i. e. RAM which is not overwritten
2544 by U-Boot. Define CONFIG_PRAM to hold the number of
2545 kB you want to reserve for pRAM. You can overwrite
2546 this default value by defining an environment
2547 variable "pram" to the number of kB you want to
2548 reserve. Note that the board info structure will
2549 still show the full amount of RAM. If pRAM is
2550 reserved, a new environment variable "mem" will
2551 automatically be defined to hold the amount of
2552 remaining RAM in a form that can be passed as boot
2553 argument to Linux, for instance like that:
2555 setenv bootargs ... mem=\${mem}
2558 This way you can tell Linux not to use this memory,
2559 either, which results in a memory region that will
2560 not be affected by reboots.
2562 *WARNING* If your board configuration uses automatic
2563 detection of the RAM size, you must make sure that
2564 this memory test is non-destructive. So far, the
2565 following board configurations are known to be
2568 IVMS8, IVML24, SPD8xx, TQM8xxL,
2569 HERMES, IP860, RPXlite, LWMON,
2572 - Access to physical memory region (> 4GB)
2573 Some basic support is provided for operations on memory not
2574 normally accessible to U-Boot - e.g. some architectures
2575 support access to more than 4GB of memory on 32-bit
2576 machines using physical address extension or similar.
2577 Define CONFIG_PHYSMEM to access this basic support, which
2578 currently only supports clearing the memory.
2583 Define this variable to stop the system in case of a
2584 fatal error, so that you have to reset it manually.
2585 This is probably NOT a good idea for an embedded
2586 system where you want the system to reboot
2587 automatically as fast as possible, but it may be
2588 useful during development since you can try to debug
2589 the conditions that lead to the situation.
2591 CONFIG_NET_RETRY_COUNT
2593 This variable defines the number of retries for
2594 network operations like ARP, RARP, TFTP, or BOOTP
2595 before giving up the operation. If not defined, a
2596 default value of 5 is used.
2600 Timeout waiting for an ARP reply in milliseconds.
2604 Timeout in milliseconds used in NFS protocol.
2605 If you encounter "ERROR: Cannot umount" in nfs command,
2606 try longer timeout such as
2607 #define CONFIG_NFS_TIMEOUT 10000UL
2609 - Command Interpreter:
2610 CONFIG_AUTO_COMPLETE
2612 Enable auto completion of commands using TAB.
2614 Note that this feature has NOT been implemented yet
2615 for the "hush" shell.
2618 CONFIG_SYS_HUSH_PARSER
2620 Define this variable to enable the "hush" shell (from
2621 Busybox) as command line interpreter, thus enabling
2622 powerful command line syntax like
2623 if...then...else...fi conditionals or `&&' and '||'
2624 constructs ("shell scripts").
2626 If undefined, you get the old, much simpler behaviour
2627 with a somewhat smaller memory footprint.
2630 CONFIG_SYS_PROMPT_HUSH_PS2
2632 This defines the secondary prompt string, which is
2633 printed when the command interpreter needs more input
2634 to complete a command. Usually "> ".
2638 In the current implementation, the local variables
2639 space and global environment variables space are
2640 separated. Local variables are those you define by
2641 simply typing `name=value'. To access a local
2642 variable later on, you have write `$name' or
2643 `${name}'; to execute the contents of a variable
2644 directly type `$name' at the command prompt.
2646 Global environment variables are those you use
2647 setenv/printenv to work with. To run a command stored
2648 in such a variable, you need to use the run command,
2649 and you must not use the '$' sign to access them.
2651 To store commands and special characters in a
2652 variable, please use double quotation marks
2653 surrounding the whole text of the variable, instead
2654 of the backslashes before semicolons and special
2657 - Commandline Editing and History:
2658 CONFIG_CMDLINE_EDITING
2660 Enable editing and History functions for interactive
2661 commandline input operations
2663 - Default Environment:
2664 CONFIG_EXTRA_ENV_SETTINGS
2666 Define this to contain any number of null terminated
2667 strings (variable = value pairs) that will be part of
2668 the default environment compiled into the boot image.
2670 For example, place something like this in your
2671 board's config file:
2673 #define CONFIG_EXTRA_ENV_SETTINGS \
2677 Warning: This method is based on knowledge about the
2678 internal format how the environment is stored by the
2679 U-Boot code. This is NOT an official, exported
2680 interface! Although it is unlikely that this format
2681 will change soon, there is no guarantee either.
2682 You better know what you are doing here.
2684 Note: overly (ab)use of the default environment is
2685 discouraged. Make sure to check other ways to preset
2686 the environment like the "source" command or the
2689 CONFIG_ENV_VARS_UBOOT_CONFIG
2691 Define this in order to add variables describing the
2692 U-Boot build configuration to the default environment.
2693 These will be named arch, cpu, board, vendor, and soc.
2695 Enabling this option will cause the following to be defined:
2703 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2705 Define this in order to add variables describing certain
2706 run-time determined information about the hardware to the
2707 environment. These will be named board_name, board_rev.
2709 CONFIG_DELAY_ENVIRONMENT
2711 Normally the environment is loaded when the board is
2712 intialised so that it is available to U-Boot. This inhibits
2713 that so that the environment is not available until
2714 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2715 this is instead controlled by the value of
2716 /config/load-environment.
2718 - DataFlash Support:
2719 CONFIG_HAS_DATAFLASH
2721 Defining this option enables DataFlash features and
2722 allows to read/write in Dataflash via the standard
2725 - Serial Flash support
2728 Defining this option enables SPI flash commands
2729 'sf probe/read/write/erase/update'.
2731 Usage requires an initial 'probe' to define the serial
2732 flash parameters, followed by read/write/erase/update
2735 The following defaults may be provided by the platform
2736 to handle the common case when only a single serial
2737 flash is present on the system.
2739 CONFIG_SF_DEFAULT_BUS Bus identifier
2740 CONFIG_SF_DEFAULT_CS Chip-select
2741 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2742 CONFIG_SF_DEFAULT_SPEED in Hz
2746 Define this option to include a destructive SPI flash
2749 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2751 Define this option to use the Bank addr/Extended addr
2752 support on SPI flashes which has size > 16Mbytes.
2754 - SystemACE Support:
2757 Adding this option adds support for Xilinx SystemACE
2758 chips attached via some sort of local bus. The address
2759 of the chip must also be defined in the
2760 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2762 #define CONFIG_SYSTEMACE
2763 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2765 When SystemACE support is added, the "ace" device type
2766 becomes available to the fat commands, i.e. fatls.
2768 - TFTP Fixed UDP Port:
2771 If this is defined, the environment variable tftpsrcp
2772 is used to supply the TFTP UDP source port value.
2773 If tftpsrcp isn't defined, the normal pseudo-random port
2774 number generator is used.
2776 Also, the environment variable tftpdstp is used to supply
2777 the TFTP UDP destination port value. If tftpdstp isn't
2778 defined, the normal port 69 is used.
2780 The purpose for tftpsrcp is to allow a TFTP server to
2781 blindly start the TFTP transfer using the pre-configured
2782 target IP address and UDP port. This has the effect of
2783 "punching through" the (Windows XP) firewall, allowing
2784 the remainder of the TFTP transfer to proceed normally.
2785 A better solution is to properly configure the firewall,
2786 but sometimes that is not allowed.
2791 This enables a generic 'hash' command which can produce
2792 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2796 Enable the hash verify command (hash -v). This adds to code
2799 CONFIG_SHA1 - support SHA1 hashing
2800 CONFIG_SHA256 - support SHA256 hashing
2802 Note: There is also a sha1sum command, which should perhaps
2803 be deprecated in favour of 'hash sha1'.
2805 - Freescale i.MX specific commands:
2806 CONFIG_CMD_HDMIDETECT
2807 This enables 'hdmidet' command which returns true if an
2808 HDMI monitor is detected. This command is i.MX 6 specific.
2811 This enables the 'bmode' (bootmode) command for forcing
2812 a boot from specific media.
2814 This is useful for forcing the ROM's usb downloader to
2815 activate upon a watchdog reset which is nice when iterating
2816 on U-Boot. Using the reset button or running bmode normal
2817 will set it back to normal. This command currently
2818 supports i.MX53 and i.MX6.
2823 This enables the RSA algorithm used for FIT image verification
2824 in U-Boot. See doc/uImage/signature for more information.
2826 The signing part is build into mkimage regardless of this
2830 - Show boot progress:
2831 CONFIG_SHOW_BOOT_PROGRESS
2833 Defining this option allows to add some board-
2834 specific code (calling a user-provided function
2835 "show_boot_progress(int)") that enables you to show
2836 the system's boot progress on some display (for
2837 example, some LED's) on your board. At the moment,
2838 the following checkpoints are implemented:
2840 - Detailed boot stage timing
2842 Define this option to get detailed timing of each stage
2843 of the boot process.
2845 CONFIG_BOOTSTAGE_USER_COUNT
2846 This is the number of available user bootstage records.
2847 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2848 a new ID will be allocated from this stash. If you exceed
2849 the limit, recording will stop.
2851 CONFIG_BOOTSTAGE_REPORT
2852 Define this to print a report before boot, similar to this:
2854 Timer summary in microseconds:
2857 3,575,678 3,575,678 board_init_f start
2858 3,575,695 17 arch_cpu_init A9
2859 3,575,777 82 arch_cpu_init done
2860 3,659,598 83,821 board_init_r start
2861 3,910,375 250,777 main_loop
2862 29,916,167 26,005,792 bootm_start
2863 30,361,327 445,160 start_kernel
2865 CONFIG_CMD_BOOTSTAGE
2866 Add a 'bootstage' command which supports printing a report
2867 and un/stashing of bootstage data.
2869 CONFIG_BOOTSTAGE_FDT
2870 Stash the bootstage information in the FDT. A root 'bootstage'
2871 node is created with each bootstage id as a child. Each child
2872 has a 'name' property and either 'mark' containing the
2873 mark time in microsecond, or 'accum' containing the
2874 accumulated time for that bootstage id in microseconds.
2879 name = "board_init_f";
2888 Code in the Linux kernel can find this in /proc/devicetree.
2890 Legacy uImage format:
2893 1 common/cmd_bootm.c before attempting to boot an image
2894 -1 common/cmd_bootm.c Image header has bad magic number
2895 2 common/cmd_bootm.c Image header has correct magic number
2896 -2 common/cmd_bootm.c Image header has bad checksum
2897 3 common/cmd_bootm.c Image header has correct checksum
2898 -3 common/cmd_bootm.c Image data has bad checksum
2899 4 common/cmd_bootm.c Image data has correct checksum
2900 -4 common/cmd_bootm.c Image is for unsupported architecture
2901 5 common/cmd_bootm.c Architecture check OK
2902 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2903 6 common/cmd_bootm.c Image Type check OK
2904 -6 common/cmd_bootm.c gunzip uncompression error
2905 -7 common/cmd_bootm.c Unimplemented compression type
2906 7 common/cmd_bootm.c Uncompression OK
2907 8 common/cmd_bootm.c No uncompress/copy overwrite error
2908 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2910 9 common/image.c Start initial ramdisk verification
2911 -10 common/image.c Ramdisk header has bad magic number
2912 -11 common/image.c Ramdisk header has bad checksum
2913 10 common/image.c Ramdisk header is OK
2914 -12 common/image.c Ramdisk data has bad checksum
2915 11 common/image.c Ramdisk data has correct checksum
2916 12 common/image.c Ramdisk verification complete, start loading
2917 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2918 13 common/image.c Start multifile image verification
2919 14 common/image.c No initial ramdisk, no multifile, continue.
2921 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2923 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2924 -31 post/post.c POST test failed, detected by post_output_backlog()
2925 -32 post/post.c POST test failed, detected by post_run_single()
2927 34 common/cmd_doc.c before loading a Image from a DOC device
2928 -35 common/cmd_doc.c Bad usage of "doc" command
2929 35 common/cmd_doc.c correct usage of "doc" command
2930 -36 common/cmd_doc.c No boot device
2931 36 common/cmd_doc.c correct boot device
2932 -37 common/cmd_doc.c Unknown Chip ID on boot device
2933 37 common/cmd_doc.c correct chip ID found, device available
2934 -38 common/cmd_doc.c Read Error on boot device
2935 38 common/cmd_doc.c reading Image header from DOC device OK
2936 -39 common/cmd_doc.c Image header has bad magic number
2937 39 common/cmd_doc.c Image header has correct magic number
2938 -40 common/cmd_doc.c Error reading Image from DOC device
2939 40 common/cmd_doc.c Image header has correct magic number
2940 41 common/cmd_ide.c before loading a Image from a IDE device
2941 -42 common/cmd_ide.c Bad usage of "ide" command
2942 42 common/cmd_ide.c correct usage of "ide" command
2943 -43 common/cmd_ide.c No boot device
2944 43 common/cmd_ide.c boot device found
2945 -44 common/cmd_ide.c Device not available
2946 44 common/cmd_ide.c Device available
2947 -45 common/cmd_ide.c wrong partition selected
2948 45 common/cmd_ide.c partition selected
2949 -46 common/cmd_ide.c Unknown partition table
2950 46 common/cmd_ide.c valid partition table found
2951 -47 common/cmd_ide.c Invalid partition type
2952 47 common/cmd_ide.c correct partition type
2953 -48 common/cmd_ide.c Error reading Image Header on boot device
2954 48 common/cmd_ide.c reading Image Header from IDE device OK
2955 -49 common/cmd_ide.c Image header has bad magic number
2956 49 common/cmd_ide.c Image header has correct magic number
2957 -50 common/cmd_ide.c Image header has bad checksum
2958 50 common/cmd_ide.c Image header has correct checksum
2959 -51 common/cmd_ide.c Error reading Image from IDE device
2960 51 common/cmd_ide.c reading Image from IDE device OK
2961 52 common/cmd_nand.c before loading a Image from a NAND device
2962 -53 common/cmd_nand.c Bad usage of "nand" command
2963 53 common/cmd_nand.c correct usage of "nand" command
2964 -54 common/cmd_nand.c No boot device
2965 54 common/cmd_nand.c boot device found
2966 -55 common/cmd_nand.c Unknown Chip ID on boot device
2967 55 common/cmd_nand.c correct chip ID found, device available
2968 -56 common/cmd_nand.c Error reading Image Header on boot device
2969 56 common/cmd_nand.c reading Image Header from NAND device OK
2970 -57 common/cmd_nand.c Image header has bad magic number
2971 57 common/cmd_nand.c Image header has correct magic number
2972 -58 common/cmd_nand.c Error reading Image from NAND device
2973 58 common/cmd_nand.c reading Image from NAND device OK
2975 -60 common/env_common.c Environment has a bad CRC, using default
2977 64 net/eth.c starting with Ethernet configuration.
2978 -64 net/eth.c no Ethernet found.
2979 65 net/eth.c Ethernet found.
2981 -80 common/cmd_net.c usage wrong
2982 80 common/cmd_net.c before calling NetLoop()
2983 -81 common/cmd_net.c some error in NetLoop() occurred
2984 81 common/cmd_net.c NetLoop() back without error
2985 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2986 82 common/cmd_net.c trying automatic boot
2987 83 common/cmd_net.c running "source" command
2988 -83 common/cmd_net.c some error in automatic boot or "source" command
2989 84 common/cmd_net.c end without errors
2994 100 common/cmd_bootm.c Kernel FIT Image has correct format
2995 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2996 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2997 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2998 102 common/cmd_bootm.c Kernel unit name specified
2999 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3000 103 common/cmd_bootm.c Found configuration node
3001 104 common/cmd_bootm.c Got kernel subimage node offset
3002 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3003 105 common/cmd_bootm.c Kernel subimage hash verification OK
3004 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3005 106 common/cmd_bootm.c Architecture check OK
3006 -106 common/cmd_bootm.c Kernel subimage has wrong type
3007 107 common/cmd_bootm.c Kernel subimage type OK
3008 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3009 108 common/cmd_bootm.c Got kernel subimage data/size
3010 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3011 -109 common/cmd_bootm.c Can't get kernel subimage type
3012 -110 common/cmd_bootm.c Can't get kernel subimage comp
3013 -111 common/cmd_bootm.c Can't get kernel subimage os
3014 -112 common/cmd_bootm.c Can't get kernel subimage load address
3015 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3017 120 common/image.c Start initial ramdisk verification
3018 -120 common/image.c Ramdisk FIT image has incorrect format
3019 121 common/image.c Ramdisk FIT image has correct format
3020 122 common/image.c No ramdisk subimage unit name, using configuration
3021 -122 common/image.c Can't get configuration for ramdisk subimage
3022 123 common/image.c Ramdisk unit name specified
3023 -124 common/image.c Can't get ramdisk subimage node offset
3024 125 common/image.c Got ramdisk subimage node offset
3025 -125 common/image.c Ramdisk subimage hash verification failed
3026 126 common/image.c Ramdisk subimage hash verification OK
3027 -126 common/image.c Ramdisk subimage for unsupported architecture
3028 127 common/image.c Architecture check OK
3029 -127 common/image.c Can't get ramdisk subimage data/size
3030 128 common/image.c Got ramdisk subimage data/size
3031 129 common/image.c Can't get ramdisk load address
3032 -129 common/image.c Got ramdisk load address
3034 -130 common/cmd_doc.c Incorrect FIT image format
3035 131 common/cmd_doc.c FIT image format OK
3037 -140 common/cmd_ide.c Incorrect FIT image format
3038 141 common/cmd_ide.c FIT image format OK
3040 -150 common/cmd_nand.c Incorrect FIT image format
3041 151 common/cmd_nand.c FIT image format OK
3043 - FIT image support:
3045 Enable support for the FIT uImage format.
3047 CONFIG_FIT_BEST_MATCH
3048 When no configuration is explicitly selected, default to the
3049 one whose fdt's compatibility field best matches that of
3050 U-Boot itself. A match is considered "best" if it matches the
3051 most specific compatibility entry of U-Boot's fdt's root node.
3052 The order of entries in the configuration's fdt is ignored.
3054 CONFIG_FIT_SIGNATURE
3055 This option enables signature verification of FIT uImages,
3056 using a hash signed and verified using RSA. See
3057 doc/uImage.FIT/signature.txt for more details.
3059 - Standalone program support:
3060 CONFIG_STANDALONE_LOAD_ADDR
3062 This option defines a board specific value for the
3063 address where standalone program gets loaded, thus
3064 overwriting the architecture dependent default
3067 - Frame Buffer Address:
3070 Define CONFIG_FB_ADDR if you want to use specific
3071 address for frame buffer. This is typically the case
3072 when using a graphics controller has separate video
3073 memory. U-Boot will then place the frame buffer at
3074 the given address instead of dynamically reserving it
3075 in system RAM by calling lcd_setmem(), which grabs
3076 the memory for the frame buffer depending on the
3077 configured panel size.
3079 Please see board_init_f function.
3081 - Automatic software updates via TFTP server
3083 CONFIG_UPDATE_TFTP_CNT_MAX
3084 CONFIG_UPDATE_TFTP_MSEC_MAX
3086 These options enable and control the auto-update feature;
3087 for a more detailed description refer to doc/README.update.
3089 - MTD Support (mtdparts command, UBI support)
3092 Adds the MTD device infrastructure from the Linux kernel.
3093 Needed for mtdparts command support.
3095 CONFIG_MTD_PARTITIONS
3097 Adds the MTD partitioning infrastructure from the Linux
3098 kernel. Needed for UBI support.
3103 Adds commands for interacting with MTD partitions formatted
3104 with the UBI flash translation layer
3106 Requires also defining CONFIG_RBTREE
3108 CONFIG_UBI_SILENCE_MSG
3110 Make the verbose messages from UBI stop printing. This leaves
3111 warnings and errors enabled.
3116 Adds commands for interacting with UBI volumes formatted as
3117 UBIFS. UBIFS is read-only in u-boot.
3119 Requires UBI support as well as CONFIG_LZO
3121 CONFIG_UBIFS_SILENCE_MSG
3123 Make the verbose messages from UBIFS stop printing. This leaves
3124 warnings and errors enabled.
3128 Enable building of SPL globally.
3131 LDSCRIPT for linking the SPL binary.
3133 CONFIG_SPL_MAX_FOOTPRINT
3134 Maximum size in memory allocated to the SPL, BSS included.
3135 When defined, the linker checks that the actual memory
3136 used by SPL from _start to __bss_end does not exceed it.
3137 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3138 must not be both defined at the same time.
3141 Maximum size of the SPL image (text, data, rodata, and
3142 linker lists sections), BSS excluded.
3143 When defined, the linker checks that the actual size does
3146 CONFIG_SPL_TEXT_BASE
3147 TEXT_BASE for linking the SPL binary.
3149 CONFIG_SPL_RELOC_TEXT_BASE
3150 Address to relocate to. If unspecified, this is equal to
3151 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3153 CONFIG_SPL_BSS_START_ADDR
3154 Link address for the BSS within the SPL binary.
3156 CONFIG_SPL_BSS_MAX_SIZE
3157 Maximum size in memory allocated to the SPL BSS.
3158 When defined, the linker checks that the actual memory used
3159 by SPL from __bss_start to __bss_end does not exceed it.
3160 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3161 must not be both defined at the same time.
3164 Adress of the start of the stack SPL will use
3166 CONFIG_SPL_RELOC_STACK
3167 Adress of the start of the stack SPL will use after
3168 relocation. If unspecified, this is equal to
3171 CONFIG_SYS_SPL_MALLOC_START
3172 Starting address of the malloc pool used in SPL.
3174 CONFIG_SYS_SPL_MALLOC_SIZE
3175 The size of the malloc pool used in SPL.
3177 CONFIG_SPL_FRAMEWORK
3178 Enable the SPL framework under common/. This framework
3179 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3180 NAND loading of the Linux Kernel.
3182 CONFIG_SPL_DISPLAY_PRINT
3183 For ARM, enable an optional function to print more information
3184 about the running system.
3186 CONFIG_SPL_INIT_MINIMAL
3187 Arch init code should be built for a very small image
3189 CONFIG_SPL_LIBCOMMON_SUPPORT
3190 Support for common/libcommon.o in SPL binary
3192 CONFIG_SPL_LIBDISK_SUPPORT
3193 Support for disk/libdisk.o in SPL binary
3195 CONFIG_SPL_I2C_SUPPORT
3196 Support for drivers/i2c/libi2c.o in SPL binary
3198 CONFIG_SPL_GPIO_SUPPORT
3199 Support for drivers/gpio/libgpio.o in SPL binary
3201 CONFIG_SPL_MMC_SUPPORT
3202 Support for drivers/mmc/libmmc.o in SPL binary
3204 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3205 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3206 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3207 Address, size and partition on the MMC to load U-Boot from
3208 when the MMC is being used in raw mode.
3210 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3211 Sector to load kernel uImage from when MMC is being
3212 used in raw mode (for Falcon mode)
3214 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3215 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3216 Sector and number of sectors to load kernel argument
3217 parameters from when MMC is being used in raw mode
3220 CONFIG_SPL_FAT_SUPPORT
3221 Support for fs/fat/libfat.o in SPL binary
3223 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3224 Filename to read to load U-Boot when reading from FAT
3226 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3227 Filename to read to load kernel uImage when reading
3228 from FAT (for Falcon mode)
3230 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3231 Filename to read to load kernel argument parameters
3232 when reading from FAT (for Falcon mode)
3234 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3235 Set this for NAND SPL on PPC mpc83xx targets, so that
3236 start.S waits for the rest of the SPL to load before
3237 continuing (the hardware starts execution after just
3238 loading the first page rather than the full 4K).
3240 CONFIG_SPL_NAND_BASE
3241 Include nand_base.c in the SPL. Requires
3242 CONFIG_SPL_NAND_DRIVERS.
3244 CONFIG_SPL_NAND_DRIVERS
3245 SPL uses normal NAND drivers, not minimal drivers.
3248 Include standard software ECC in the SPL
3250 CONFIG_SPL_NAND_SIMPLE
3251 Support for NAND boot using simple NAND drivers that
3252 expose the cmd_ctrl() interface.
3254 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3255 Set for the SPL on PPC mpc8xxx targets, support for
3256 drivers/ddr/fsl/libddr.o in SPL binary.
3258 CONFIG_SPL_COMMON_INIT_DDR
3259 Set for common ddr init with serial presence detect in
3262 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3263 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3264 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3265 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3266 CONFIG_SYS_NAND_ECCBYTES
3267 Defines the size and behavior of the NAND that SPL uses
3270 CONFIG_SYS_NAND_U_BOOT_OFFS
3271 Location in NAND to read U-Boot from
3273 CONFIG_SYS_NAND_U_BOOT_DST
3274 Location in memory to load U-Boot to
3276 CONFIG_SYS_NAND_U_BOOT_SIZE
3277 Size of image to load
3279 CONFIG_SYS_NAND_U_BOOT_START
3280 Entry point in loaded image to jump to
3282 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3283 Define this if you need to first read the OOB and then the
3284 data. This is used for example on davinci plattforms.
3286 CONFIG_SPL_OMAP3_ID_NAND
3287 Support for an OMAP3-specific set of functions to return the
3288 ID and MFR of the first attached NAND chip, if present.
3290 CONFIG_SPL_SERIAL_SUPPORT
3291 Support for drivers/serial/libserial.o in SPL binary
3293 CONFIG_SPL_SPI_FLASH_SUPPORT
3294 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3296 CONFIG_SPL_SPI_SUPPORT
3297 Support for drivers/spi/libspi.o in SPL binary
3299 CONFIG_SPL_RAM_DEVICE
3300 Support for running image already present in ram, in SPL binary
3302 CONFIG_SPL_LIBGENERIC_SUPPORT
3303 Support for lib/libgeneric.o in SPL binary
3305 CONFIG_SPL_ENV_SUPPORT
3306 Support for the environment operating in SPL binary
3308 CONFIG_SPL_NET_SUPPORT
3309 Support for the net/libnet.o in SPL binary.
3310 It conflicts with SPL env from storage medium specified by
3311 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3314 Image offset to which the SPL should be padded before appending
3315 the SPL payload. By default, this is defined as
3316 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3317 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3318 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3321 Final target image containing SPL and payload. Some SPLs
3322 use an arch-specific makefile fragment instead, for
3323 example if more than one image needs to be produced.
3325 CONFIG_FIT_SPL_PRINT
3326 Printing information about a FIT image adds quite a bit of
3327 code to SPL. So this is normally disabled in SPL. Use this
3328 option to re-enable it. This will affect the output of the
3329 bootm command when booting a FIT image.
3333 Enable building of TPL globally.
3336 Image offset to which the TPL should be padded before appending
3337 the TPL payload. By default, this is defined as
3338 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3339 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3340 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3345 [so far only for SMDK2400 boards]
3347 - Modem support enable:
3348 CONFIG_MODEM_SUPPORT
3350 - RTS/CTS Flow control enable:
3353 - Modem debug support:
3354 CONFIG_MODEM_SUPPORT_DEBUG
3356 Enables debugging stuff (char screen[1024], dbg())
3357 for modem support. Useful only with BDI2000.
3359 - Interrupt support (PPC):
3361 There are common interrupt_init() and timer_interrupt()
3362 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3363 for CPU specific initialization. interrupt_init_cpu()
3364 should set decrementer_count to appropriate value. If
3365 CPU resets decrementer automatically after interrupt
3366 (ppc4xx) it should set decrementer_count to zero.
3367 timer_interrupt() calls timer_interrupt_cpu() for CPU
3368 specific handling. If board has watchdog / status_led
3369 / other_activity_monitor it works automatically from
3370 general timer_interrupt().
3374 In the target system modem support is enabled when a
3375 specific key (key combination) is pressed during
3376 power-on. Otherwise U-Boot will boot normally
3377 (autoboot). The key_pressed() function is called from
3378 board_init(). Currently key_pressed() is a dummy
3379 function, returning 1 and thus enabling modem
3382 If there are no modem init strings in the
3383 environment, U-Boot proceed to autoboot; the
3384 previous output (banner, info printfs) will be
3387 See also: doc/README.Modem
3389 Board initialization settings:
3390 ------------------------------
3392 During Initialization u-boot calls a number of board specific functions
3393 to allow the preparation of board specific prerequisites, e.g. pin setup
3394 before drivers are initialized. To enable these callbacks the
3395 following configuration macros have to be defined. Currently this is
3396 architecture specific, so please check arch/your_architecture/lib/board.c
3397 typically in board_init_f() and board_init_r().
3399 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3400 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3401 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3402 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3404 Configuration Settings:
3405 -----------------------
3407 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3408 undefine this when you're short of memory.
3410 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3411 width of the commands listed in the 'help' command output.
3413 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3414 prompt for user input.
3416 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3418 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3420 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3422 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3423 the application (usually a Linux kernel) when it is
3426 - CONFIG_SYS_BAUDRATE_TABLE:
3427 List of legal baudrate settings for this board.
3429 - CONFIG_SYS_CONSOLE_INFO_QUIET
3430 Suppress display of console information at boot.
3432 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3433 If the board specific function
3434 extern int overwrite_console (void);
3435 returns 1, the stdin, stderr and stdout are switched to the
3436 serial port, else the settings in the environment are used.
3438 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3439 Enable the call to overwrite_console().
3441 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3442 Enable overwrite of previous console environment settings.
3444 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3445 Begin and End addresses of the area used by the
3448 - CONFIG_SYS_ALT_MEMTEST:
3449 Enable an alternate, more extensive memory test.
3451 - CONFIG_SYS_MEMTEST_SCRATCH:
3452 Scratch address used by the alternate memory test
3453 You only need to set this if address zero isn't writeable
3455 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3456 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3457 this specified memory area will get subtracted from the top
3458 (end) of RAM and won't get "touched" at all by U-Boot. By
3459 fixing up gd->ram_size the Linux kernel should gets passed
3460 the now "corrected" memory size and won't touch it either.
3461 This should work for arch/ppc and arch/powerpc. Only Linux
3462 board ports in arch/powerpc with bootwrapper support that
3463 recalculate the memory size from the SDRAM controller setup
3464 will have to get fixed in Linux additionally.
3466 This option can be used as a workaround for the 440EPx/GRx
3467 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3470 WARNING: Please make sure that this value is a multiple of
3471 the Linux page size (normally 4k). If this is not the case,
3472 then the end address of the Linux memory will be located at a
3473 non page size aligned address and this could cause major
3476 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3477 Enable temporary baudrate change while serial download
3479 - CONFIG_SYS_SDRAM_BASE:
3480 Physical start address of SDRAM. _Must_ be 0 here.
3482 - CONFIG_SYS_MBIO_BASE:
3483 Physical start address of Motherboard I/O (if using a
3486 - CONFIG_SYS_FLASH_BASE:
3487 Physical start address of Flash memory.
3489 - CONFIG_SYS_MONITOR_BASE:
3490 Physical start address of boot monitor code (set by
3491 make config files to be same as the text base address
3492 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3493 CONFIG_SYS_FLASH_BASE when booting from flash.
3495 - CONFIG_SYS_MONITOR_LEN:
3496 Size of memory reserved for monitor code, used to
3497 determine _at_compile_time_ (!) if the environment is
3498 embedded within the U-Boot image, or in a separate
3501 - CONFIG_SYS_MALLOC_LEN:
3502 Size of DRAM reserved for malloc() use.
3504 - CONFIG_SYS_BOOTM_LEN:
3505 Normally compressed uImages are limited to an
3506 uncompressed size of 8 MBytes. If this is not enough,
3507 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3508 to adjust this setting to your needs.
3510 - CONFIG_SYS_BOOTMAPSZ:
3511 Maximum size of memory mapped by the startup code of
3512 the Linux kernel; all data that must be processed by
3513 the Linux kernel (bd_info, boot arguments, FDT blob if
3514 used) must be put below this limit, unless "bootm_low"
3515 environment variable is defined and non-zero. In such case
3516 all data for the Linux kernel must be between "bootm_low"
3517 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3518 variable "bootm_mapsize" will override the value of
3519 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3520 then the value in "bootm_size" will be used instead.
3522 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3523 Enable initrd_high functionality. If defined then the
3524 initrd_high feature is enabled and the bootm ramdisk subcommand
3527 - CONFIG_SYS_BOOT_GET_CMDLINE:
3528 Enables allocating and saving kernel cmdline in space between
3529 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3531 - CONFIG_SYS_BOOT_GET_KBD:
3532 Enables allocating and saving a kernel copy of the bd_info in
3533 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3535 - CONFIG_SYS_MAX_FLASH_BANKS:
3536 Max number of Flash memory banks
3538 - CONFIG_SYS_MAX_FLASH_SECT:
3539 Max number of sectors on a Flash chip
3541 - CONFIG_SYS_FLASH_ERASE_TOUT:
3542 Timeout for Flash erase operations (in ms)
3544 - CONFIG_SYS_FLASH_WRITE_TOUT:
3545 Timeout for Flash write operations (in ms)
3547 - CONFIG_SYS_FLASH_LOCK_TOUT
3548 Timeout for Flash set sector lock bit operation (in ms)
3550 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3551 Timeout for Flash clear lock bits operation (in ms)
3553 - CONFIG_SYS_FLASH_PROTECTION
3554 If defined, hardware flash sectors protection is used
3555 instead of U-Boot software protection.
3557 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3559 Enable TFTP transfers directly to flash memory;
3560 without this option such a download has to be
3561 performed in two steps: (1) download to RAM, and (2)
3562 copy from RAM to flash.
3564 The two-step approach is usually more reliable, since
3565 you can check if the download worked before you erase
3566 the flash, but in some situations (when system RAM is
3567 too limited to allow for a temporary copy of the
3568 downloaded image) this option may be very useful.
3570 - CONFIG_SYS_FLASH_CFI:
3571 Define if the flash driver uses extra elements in the
3572 common flash structure for storing flash geometry.
3574 - CONFIG_FLASH_CFI_DRIVER
3575 This option also enables the building of the cfi_flash driver
3576 in the drivers directory
3578 - CONFIG_FLASH_CFI_MTD
3579 This option enables the building of the cfi_mtd driver
3580 in the drivers directory. The driver exports CFI flash
3583 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3584 Use buffered writes to flash.
3586 - CONFIG_FLASH_SPANSION_S29WS_N
3587 s29ws-n MirrorBit flash has non-standard addresses for buffered
3590 - CONFIG_SYS_FLASH_QUIET_TEST
3591 If this option is defined, the common CFI flash doesn't
3592 print it's warning upon not recognized FLASH banks. This
3593 is useful, if some of the configured banks are only
3594 optionally available.
3596 - CONFIG_FLASH_SHOW_PROGRESS
3597 If defined (must be an integer), print out countdown
3598 digits and dots. Recommended value: 45 (9..1) for 80
3599 column displays, 15 (3..1) for 40 column displays.
3601 - CONFIG_FLASH_VERIFY
3602 If defined, the content of the flash (destination) is compared
3603 against the source after the write operation. An error message
3604 will be printed when the contents are not identical.
3605 Please note that this option is useless in nearly all cases,
3606 since such flash programming errors usually are detected earlier
3607 while unprotecting/erasing/programming. Please only enable
3608 this option if you really know what you are doing.
3610 - CONFIG_SYS_RX_ETH_BUFFER:
3611 Defines the number of Ethernet receive buffers. On some
3612 Ethernet controllers it is recommended to set this value
3613 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3614 buffers can be full shortly after enabling the interface
3615 on high Ethernet traffic.
3616 Defaults to 4 if not defined.
3618 - CONFIG_ENV_MAX_ENTRIES
3620 Maximum number of entries in the hash table that is used
3621 internally to store the environment settings. The default
3622 setting is supposed to be generous and should work in most
3623 cases. This setting can be used to tune behaviour; see
3624 lib/hashtable.c for details.
3626 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3627 - CONFIG_ENV_FLAGS_LIST_STATIC
3628 Enable validation of the values given to environment variables when
3629 calling env set. Variables can be restricted to only decimal,
3630 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3631 the variables can also be restricted to IP address or MAC address.
3633 The format of the list is:
3634 type_attribute = [s|d|x|b|i|m]
3635 access_atribute = [a|r|o|c]
3636 attributes = type_attribute[access_atribute]
3637 entry = variable_name[:attributes]
3640 The type attributes are:
3641 s - String (default)
3644 b - Boolean ([1yYtT|0nNfF])
3648 The access attributes are:
3654 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3655 Define this to a list (string) to define the ".flags"
3656 envirnoment variable in the default or embedded environment.
3658 - CONFIG_ENV_FLAGS_LIST_STATIC
3659 Define this to a list (string) to define validation that
3660 should be done if an entry is not found in the ".flags"
3661 environment variable. To override a setting in the static
3662 list, simply add an entry for the same variable name to the
3665 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3666 If defined, don't allow the -f switch to env set override variable
3669 - CONFIG_SYS_GENERIC_BOARD
3670 This selects the architecture-generic board system instead of the
3671 architecture-specific board files. It is intended to move boards
3672 to this new framework over time. Defining this will disable the
3673 arch/foo/lib/board.c file and use common/board_f.c and
3674 common/board_r.c instead. To use this option your architecture
3675 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3676 its config.mk file). If you find problems enabling this option on
3677 your board please report the problem and send patches!
3679 - CONFIG_SYS_SYM_OFFSETS
3680 This is set by architectures that use offsets for link symbols
3681 instead of absolute values. So bss_start is obtained using an
3682 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3683 directly. You should not need to touch this setting.
3685 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3686 This is set by OMAP boards for the max time that reset should
3687 be asserted. See doc/README.omap-reset-time for details on how
3688 the value can be calulated on a given board.
3690 The following definitions that deal with the placement and management
3691 of environment data (variable area); in general, we support the
3692 following configurations:
3694 - CONFIG_BUILD_ENVCRC:
3696 Builds up envcrc with the target environment so that external utils
3697 may easily extract it and embed it in final U-Boot images.
3699 - CONFIG_ENV_IS_IN_FLASH:
3701 Define this if the environment is in flash memory.
3703 a) The environment occupies one whole flash sector, which is
3704 "embedded" in the text segment with the U-Boot code. This
3705 happens usually with "bottom boot sector" or "top boot
3706 sector" type flash chips, which have several smaller
3707 sectors at the start or the end. For instance, such a
3708 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3709 such a case you would place the environment in one of the
3710 4 kB sectors - with U-Boot code before and after it. With
3711 "top boot sector" type flash chips, you would put the
3712 environment in one of the last sectors, leaving a gap
3713 between U-Boot and the environment.
3715 - CONFIG_ENV_OFFSET:
3717 Offset of environment data (variable area) to the
3718 beginning of flash memory; for instance, with bottom boot
3719 type flash chips the second sector can be used: the offset
3720 for this sector is given here.
3722 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3726 This is just another way to specify the start address of
3727 the flash sector containing the environment (instead of
3730 - CONFIG_ENV_SECT_SIZE:
3732 Size of the sector containing the environment.
3735 b) Sometimes flash chips have few, equal sized, BIG sectors.
3736 In such a case you don't want to spend a whole sector for
3741 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3742 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3743 of this flash sector for the environment. This saves
3744 memory for the RAM copy of the environment.
3746 It may also save flash memory if you decide to use this
3747 when your environment is "embedded" within U-Boot code,
3748 since then the remainder of the flash sector could be used
3749 for U-Boot code. It should be pointed out that this is
3750 STRONGLY DISCOURAGED from a robustness point of view:
3751 updating the environment in flash makes it always
3752 necessary to erase the WHOLE sector. If something goes
3753 wrong before the contents has been restored from a copy in
3754 RAM, your target system will be dead.
3756 - CONFIG_ENV_ADDR_REDUND
3757 CONFIG_ENV_SIZE_REDUND
3759 These settings describe a second storage area used to hold
3760 a redundant copy of the environment data, so that there is
3761 a valid backup copy in case there is a power failure during
3762 a "saveenv" operation.
3764 BE CAREFUL! Any changes to the flash layout, and some changes to the
3765 source code will make it necessary to adapt <board>/u-boot.lds*
3769 - CONFIG_ENV_IS_IN_NVRAM:
3771 Define this if you have some non-volatile memory device
3772 (NVRAM, battery buffered SRAM) which you want to use for the
3778 These two #defines are used to determine the memory area you
3779 want to use for environment. It is assumed that this memory
3780 can just be read and written to, without any special
3783 BE CAREFUL! The first access to the environment happens quite early
3784 in U-Boot initalization (when we try to get the setting of for the
3785 console baudrate). You *MUST* have mapped your NVRAM area then, or
3788 Please note that even with NVRAM we still use a copy of the
3789 environment in RAM: we could work on NVRAM directly, but we want to
3790 keep settings there always unmodified except somebody uses "saveenv"
3791 to save the current settings.
3794 - CONFIG_ENV_IS_IN_EEPROM:
3796 Use this if you have an EEPROM or similar serial access
3797 device and a driver for it.
3799 - CONFIG_ENV_OFFSET:
3802 These two #defines specify the offset and size of the
3803 environment area within the total memory of your EEPROM.
3805 - CONFIG_SYS_I2C_EEPROM_ADDR:
3806 If defined, specified the chip address of the EEPROM device.
3807 The default address is zero.
3809 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3810 If defined, the number of bits used to address bytes in a
3811 single page in the EEPROM device. A 64 byte page, for example
3812 would require six bits.
3814 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3815 If defined, the number of milliseconds to delay between
3816 page writes. The default is zero milliseconds.
3818 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3819 The length in bytes of the EEPROM memory array address. Note
3820 that this is NOT the chip address length!
3822 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3823 EEPROM chips that implement "address overflow" are ones
3824 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3825 address and the extra bits end up in the "chip address" bit
3826 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3829 Note that we consider the length of the address field to
3830 still be one byte because the extra address bits are hidden
3831 in the chip address.
3833 - CONFIG_SYS_EEPROM_SIZE:
3834 The size in bytes of the EEPROM device.
3836 - CONFIG_ENV_EEPROM_IS_ON_I2C
3837 define this, if you have I2C and SPI activated, and your
3838 EEPROM, which holds the environment, is on the I2C bus.
3840 - CONFIG_I2C_ENV_EEPROM_BUS
3841 if you have an Environment on an EEPROM reached over
3842 I2C muxes, you can define here, how to reach this
3843 EEPROM. For example:
3845 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3847 EEPROM which holds the environment, is reached over
3848 a pca9547 i2c mux with address 0x70, channel 3.
3850 - CONFIG_ENV_IS_IN_DATAFLASH:
3852 Define this if you have a DataFlash memory device which you
3853 want to use for the environment.
3855 - CONFIG_ENV_OFFSET:
3859 These three #defines specify the offset and size of the
3860 environment area within the total memory of your DataFlash placed
3861 at the specified address.
3863 - CONFIG_ENV_IS_IN_REMOTE:
3865 Define this if you have a remote memory space which you
3866 want to use for the local device's environment.
3871 These two #defines specify the address and size of the
3872 environment area within the remote memory space. The
3873 local device can get the environment from remote memory
3874 space by SRIO or PCIE links.
3876 BE CAREFUL! For some special cases, the local device can not use
3877 "saveenv" command. For example, the local device will get the
3878 environment stored in a remote NOR flash by SRIO or PCIE link,
3879 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3881 - CONFIG_ENV_IS_IN_NAND:
3883 Define this if you have a NAND device which you want to use
3884 for the environment.
3886 - CONFIG_ENV_OFFSET:
3889 These two #defines specify the offset and size of the environment
3890 area within the first NAND device. CONFIG_ENV_OFFSET must be
3891 aligned to an erase block boundary.
3893 - CONFIG_ENV_OFFSET_REDUND (optional):
3895 This setting describes a second storage area of CONFIG_ENV_SIZE
3896 size used to hold a redundant copy of the environment data, so
3897 that there is a valid backup copy in case there is a power failure
3898 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3899 aligned to an erase block boundary.
3901 - CONFIG_ENV_RANGE (optional):
3903 Specifies the length of the region in which the environment
3904 can be written. This should be a multiple of the NAND device's
3905 block size. Specifying a range with more erase blocks than
3906 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3907 the range to be avoided.
3909 - CONFIG_ENV_OFFSET_OOB (optional):
3911 Enables support for dynamically retrieving the offset of the
3912 environment from block zero's out-of-band data. The
3913 "nand env.oob" command can be used to record this offset.
3914 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3915 using CONFIG_ENV_OFFSET_OOB.
3917 - CONFIG_NAND_ENV_DST
3919 Defines address in RAM to which the nand_spl code should copy the
3920 environment. If redundant environment is used, it will be copied to
3921 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3923 - CONFIG_ENV_IS_IN_UBI:
3925 Define this if you have an UBI volume that you want to use for the
3926 environment. This has the benefit of wear-leveling the environment
3927 accesses, which is important on NAND.
3929 - CONFIG_ENV_UBI_PART:
3931 Define this to a string that is the mtd partition containing the UBI.
3933 - CONFIG_ENV_UBI_VOLUME:
3935 Define this to the name of the volume that you want to store the
3938 - CONFIG_ENV_UBI_VOLUME_REDUND:
3940 Define this to the name of another volume to store a second copy of
3941 the environment in. This will enable redundant environments in UBI.
3942 It is assumed that both volumes are in the same MTD partition.
3944 - CONFIG_UBI_SILENCE_MSG
3945 - CONFIG_UBIFS_SILENCE_MSG
3947 You will probably want to define these to avoid a really noisy system
3948 when storing the env in UBI.
3950 - CONFIG_ENV_IS_IN_MMC:
3952 Define this if you have an MMC device which you want to use for the
3955 - CONFIG_SYS_MMC_ENV_DEV:
3957 Specifies which MMC device the environment is stored in.
3959 - CONFIG_SYS_MMC_ENV_PART (optional):
3961 Specifies which MMC partition the environment is stored in. If not
3962 set, defaults to partition 0, the user area. Common values might be
3963 1 (first MMC boot partition), 2 (second MMC boot partition).
3965 - CONFIG_ENV_OFFSET:
3968 These two #defines specify the offset and size of the environment
3969 area within the specified MMC device.
3971 If offset is positive (the usual case), it is treated as relative to
3972 the start of the MMC partition. If offset is negative, it is treated
3973 as relative to the end of the MMC partition. This can be useful if
3974 your board may be fitted with different MMC devices, which have
3975 different sizes for the MMC partitions, and you always want the
3976 environment placed at the very end of the partition, to leave the
3977 maximum possible space before it, to store other data.
3979 These two values are in units of bytes, but must be aligned to an
3980 MMC sector boundary.
3982 - CONFIG_ENV_OFFSET_REDUND (optional):
3984 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3985 hold a redundant copy of the environment data. This provides a
3986 valid backup copy in case the other copy is corrupted, e.g. due
3987 to a power failure during a "saveenv" operation.
3989 This value may also be positive or negative; this is handled in the
3990 same way as CONFIG_ENV_OFFSET.
3992 This value is also in units of bytes, but must also be aligned to
3993 an MMC sector boundary.
3995 - CONFIG_ENV_SIZE_REDUND (optional):
3997 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3998 set. If this value is set, it must be set to the same value as
4001 - CONFIG_SYS_SPI_INIT_OFFSET
4003 Defines offset to the initial SPI buffer area in DPRAM. The
4004 area is used at an early stage (ROM part) if the environment
4005 is configured to reside in the SPI EEPROM: We need a 520 byte
4006 scratch DPRAM area. It is used between the two initialization
4007 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4008 to be a good choice since it makes it far enough from the
4009 start of the data area as well as from the stack pointer.
4011 Please note that the environment is read-only until the monitor
4012 has been relocated to RAM and a RAM copy of the environment has been
4013 created; also, when using EEPROM you will have to use getenv_f()
4014 until then to read environment variables.
4016 The environment is protected by a CRC32 checksum. Before the monitor
4017 is relocated into RAM, as a result of a bad CRC you will be working
4018 with the compiled-in default environment - *silently*!!! [This is
4019 necessary, because the first environment variable we need is the
4020 "baudrate" setting for the console - if we have a bad CRC, we don't
4021 have any device yet where we could complain.]
4023 Note: once the monitor has been relocated, then it will complain if
4024 the default environment is used; a new CRC is computed as soon as you
4025 use the "saveenv" command to store a valid environment.
4027 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4028 Echo the inverted Ethernet link state to the fault LED.
4030 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4031 also needs to be defined.
4033 - CONFIG_SYS_FAULT_MII_ADDR:
4034 MII address of the PHY to check for the Ethernet link state.
4036 - CONFIG_NS16550_MIN_FUNCTIONS:
4037 Define this if you desire to only have use of the NS16550_init
4038 and NS16550_putc functions for the serial driver located at
4039 drivers/serial/ns16550.c. This option is useful for saving
4040 space for already greatly restricted images, including but not
4041 limited to NAND_SPL configurations.
4043 - CONFIG_DISPLAY_BOARDINFO
4044 Display information about the board that U-Boot is running on
4045 when U-Boot starts up. The board function checkboard() is called
4048 - CONFIG_DISPLAY_BOARDINFO_LATE
4049 Similar to the previous option, but display this information
4050 later, once stdio is running and output goes to the LCD, if
4053 Low Level (hardware related) configuration options:
4054 ---------------------------------------------------
4056 - CONFIG_SYS_CACHELINE_SIZE:
4057 Cache Line Size of the CPU.
4059 - CONFIG_SYS_DEFAULT_IMMR:
4060 Default address of the IMMR after system reset.
4062 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4063 and RPXsuper) to be able to adjust the position of
4064 the IMMR register after a reset.
4066 - CONFIG_SYS_CCSRBAR_DEFAULT:
4067 Default (power-on reset) physical address of CCSR on Freescale
4070 - CONFIG_SYS_CCSRBAR:
4071 Virtual address of CCSR. On a 32-bit build, this is typically
4072 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4074 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4075 for cross-platform code that uses that macro instead.
4077 - CONFIG_SYS_CCSRBAR_PHYS:
4078 Physical address of CCSR. CCSR can be relocated to a new
4079 physical address, if desired. In this case, this macro should
4080 be set to that address. Otherwise, it should be set to the
4081 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4082 is typically relocated on 36-bit builds. It is recommended
4083 that this macro be defined via the _HIGH and _LOW macros:
4085 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4086 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4088 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4089 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4090 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4091 used in assembly code, so it must not contain typecasts or
4092 integer size suffixes (e.g. "ULL").
4094 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4095 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4096 used in assembly code, so it must not contain typecasts or
4097 integer size suffixes (e.g. "ULL").
4099 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4100 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4101 forced to a value that ensures that CCSR is not relocated.
4103 - Floppy Disk Support:
4104 CONFIG_SYS_FDC_DRIVE_NUMBER
4106 the default drive number (default value 0)
4108 CONFIG_SYS_ISA_IO_STRIDE
4110 defines the spacing between FDC chipset registers
4113 CONFIG_SYS_ISA_IO_OFFSET
4115 defines the offset of register from address. It
4116 depends on which part of the data bus is connected to
4117 the FDC chipset. (default value 0)
4119 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4120 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4123 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4124 fdc_hw_init() is called at the beginning of the FDC
4125 setup. fdc_hw_init() must be provided by the board
4126 source code. It is used to make hardware dependant
4130 Most IDE controllers were designed to be connected with PCI
4131 interface. Only few of them were designed for AHB interface.
4132 When software is doing ATA command and data transfer to
4133 IDE devices through IDE-AHB controller, some additional
4134 registers accessing to these kind of IDE-AHB controller
4137 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4138 DO NOT CHANGE unless you know exactly what you're
4139 doing! (11-4) [MPC8xx/82xx systems only]
4141 - CONFIG_SYS_INIT_RAM_ADDR:
4143 Start address of memory area that can be used for
4144 initial data and stack; please note that this must be
4145 writable memory that is working WITHOUT special
4146 initialization, i. e. you CANNOT use normal RAM which
4147 will become available only after programming the
4148 memory controller and running certain initialization
4151 U-Boot uses the following memory types:
4152 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4153 - MPC824X: data cache
4154 - PPC4xx: data cache
4156 - CONFIG_SYS_GBL_DATA_OFFSET:
4158 Offset of the initial data structure in the memory
4159 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4160 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4161 data is located at the end of the available space
4162 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4163 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4164 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4165 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4168 On the MPC824X (or other systems that use the data
4169 cache for initial memory) the address chosen for
4170 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4171 point to an otherwise UNUSED address space between
4172 the top of RAM and the start of the PCI space.
4174 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4176 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4178 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4180 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4182 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4184 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4186 - CONFIG_SYS_OR_TIMING_SDRAM:
4189 - CONFIG_SYS_MAMR_PTA:
4190 periodic timer for refresh
4192 - CONFIG_SYS_DER: Debug Event Register (37-47)
4194 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4195 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4196 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4197 CONFIG_SYS_BR1_PRELIM:
4198 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4200 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4201 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4202 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4203 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4205 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4206 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4207 Machine Mode Register and Memory Periodic Timer
4208 Prescaler definitions (SDRAM timing)
4210 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4211 enable I2C microcode relocation patch (MPC8xx);
4212 define relocation offset in DPRAM [DSP2]
4214 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4215 enable SMC microcode relocation patch (MPC8xx);
4216 define relocation offset in DPRAM [SMC1]
4218 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4219 enable SPI microcode relocation patch (MPC8xx);
4220 define relocation offset in DPRAM [SCC4]
4222 - CONFIG_SYS_USE_OSCCLK:
4223 Use OSCM clock mode on MBX8xx board. Be careful,
4224 wrong setting might damage your board. Read
4225 doc/README.MBX before setting this variable!
4227 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4228 Offset of the bootmode word in DPRAM used by post
4229 (Power On Self Tests). This definition overrides
4230 #define'd default value in commproc.h resp.
4233 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4234 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4235 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4236 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4237 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4238 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4239 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4240 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4241 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4243 - CONFIG_PCI_DISABLE_PCIE:
4244 Disable PCI-Express on systems where it is supported but not
4247 - CONFIG_PCI_ENUM_ONLY
4248 Only scan through and get the devices on the busses.
4249 Don't do any setup work, presumably because someone or
4250 something has already done it, and we don't need to do it
4251 a second time. Useful for platforms that are pre-booted
4252 by coreboot or similar.
4254 - CONFIG_PCI_INDIRECT_BRIDGE:
4255 Enable support for indirect PCI bridges.
4258 Chip has SRIO or not
4261 Board has SRIO 1 port available
4264 Board has SRIO 2 port available
4266 - CONFIG_SRIO_PCIE_BOOT_MASTER
4267 Board can support master function for Boot from SRIO and PCIE
4269 - CONFIG_SYS_SRIOn_MEM_VIRT:
4270 Virtual Address of SRIO port 'n' memory region
4272 - CONFIG_SYS_SRIOn_MEM_PHYS:
4273 Physical Address of SRIO port 'n' memory region
4275 - CONFIG_SYS_SRIOn_MEM_SIZE:
4276 Size of SRIO port 'n' memory region
4278 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4279 Defined to tell the NAND controller that the NAND chip is using
4281 Not all NAND drivers use this symbol.
4282 Example of drivers that use it:
4283 - drivers/mtd/nand/ndfc.c
4284 - drivers/mtd/nand/mxc_nand.c
4286 - CONFIG_SYS_NDFC_EBC0_CFG
4287 Sets the EBC0_CFG register for the NDFC. If not defined
4288 a default value will be used.
4291 Get DDR timing information from an I2C EEPROM. Common
4292 with pluggable memory modules such as SODIMMs
4295 I2C address of the SPD EEPROM
4297 - CONFIG_SYS_SPD_BUS_NUM
4298 If SPD EEPROM is on an I2C bus other than the first
4299 one, specify here. Note that the value must resolve
4300 to something your driver can deal with.
4302 - CONFIG_SYS_DDR_RAW_TIMING
4303 Get DDR timing information from other than SPD. Common with
4304 soldered DDR chips onboard without SPD. DDR raw timing
4305 parameters are extracted from datasheet and hard-coded into
4306 header files or board specific files.
4308 - CONFIG_FSL_DDR_INTERACTIVE
4309 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4311 - CONFIG_SYS_83XX_DDR_USES_CS0
4312 Only for 83xx systems. If specified, then DDR should
4313 be configured using CS0 and CS1 instead of CS2 and CS3.
4315 - CONFIG_ETHER_ON_FEC[12]
4316 Define to enable FEC[12] on a 8xx series processor.
4318 - CONFIG_FEC[12]_PHY
4319 Define to the hardcoded PHY address which corresponds
4320 to the given FEC; i. e.
4321 #define CONFIG_FEC1_PHY 4
4322 means that the PHY with address 4 is connected to FEC1
4324 When set to -1, means to probe for first available.
4326 - CONFIG_FEC[12]_PHY_NORXERR
4327 The PHY does not have a RXERR line (RMII only).
4328 (so program the FEC to ignore it).
4331 Enable RMII mode for all FECs.
4332 Note that this is a global option, we can't
4333 have one FEC in standard MII mode and another in RMII mode.
4335 - CONFIG_CRC32_VERIFY
4336 Add a verify option to the crc32 command.
4339 => crc32 -v <address> <count> <crc32>
4341 Where address/count indicate a memory area
4342 and crc32 is the correct crc32 which the
4346 Add the "loopw" memory command. This only takes effect if
4347 the memory commands are activated globally (CONFIG_CMD_MEM).
4350 Add the "mdc" and "mwc" memory commands. These are cyclic
4355 This command will print 4 bytes (10,11,12,13) each 500 ms.
4357 => mwc.l 100 12345678 10
4358 This command will write 12345678 to address 100 all 10 ms.
4360 This only takes effect if the memory commands are activated
4361 globally (CONFIG_CMD_MEM).
4363 - CONFIG_SKIP_LOWLEVEL_INIT
4364 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4365 low level initializations (like setting up the memory
4366 controller) are omitted and/or U-Boot does not
4367 relocate itself into RAM.
4369 Normally this variable MUST NOT be defined. The only
4370 exception is when U-Boot is loaded (to RAM) by some
4371 other boot loader or by a debugger which performs
4372 these initializations itself.
4375 Modifies the behaviour of start.S when compiling a loader
4376 that is executed before the actual U-Boot. E.g. when
4377 compiling a NAND SPL.
4380 Modifies the behaviour of start.S when compiling a loader
4381 that is executed after the SPL and before the actual U-Boot.
4382 It is loaded by the SPL.
4384 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4385 Only for 85xx systems. If this variable is specified, the section
4386 .resetvec is not kept and the section .bootpg is placed in the
4387 previous 4k of the .text section.
4389 - CONFIG_ARCH_MAP_SYSMEM
4390 Generally U-Boot (and in particular the md command) uses
4391 effective address. It is therefore not necessary to regard
4392 U-Boot address as virtual addresses that need to be translated
4393 to physical addresses. However, sandbox requires this, since
4394 it maintains its own little RAM buffer which contains all
4395 addressable memory. This option causes some memory accesses
4396 to be mapped through map_sysmem() / unmap_sysmem().
4398 - CONFIG_USE_ARCH_MEMCPY
4399 CONFIG_USE_ARCH_MEMSET
4400 If these options are used a optimized version of memcpy/memset will
4401 be used if available. These functions may be faster under some
4402 conditions but may increase the binary size.
4404 - CONFIG_X86_RESET_VECTOR
4405 If defined, the x86 reset vector code is included. This is not
4406 needed when U-Boot is running from Coreboot.
4409 Defines the MPU clock speed (in MHz).
4411 NOTE : currently only supported on AM335x platforms.
4413 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4414 Enables the RTC32K OSC on AM33xx based plattforms
4416 Freescale QE/FMAN Firmware Support:
4417 -----------------------------------
4419 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4420 loading of "firmware", which is encoded in the QE firmware binary format.
4421 This firmware often needs to be loaded during U-Boot booting, so macros
4422 are used to identify the storage device (NOR flash, SPI, etc) and the address
4425 - CONFIG_SYS_QE_FMAN_FW_ADDR
4426 The address in the storage device where the firmware is located. The
4427 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4430 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4431 The maximum possible size of the firmware. The firmware binary format
4432 has a field that specifies the actual size of the firmware, but it
4433 might not be possible to read any part of the firmware unless some
4434 local storage is allocated to hold the entire firmware first.
4436 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4437 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4438 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4439 virtual address in NOR flash.
4441 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4442 Specifies that QE/FMAN firmware is located in NAND flash.
4443 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4445 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4446 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4447 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4449 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4450 Specifies that QE/FMAN firmware is located on the primary SPI
4451 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4453 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4454 Specifies that QE/FMAN firmware is located in the remote (master)
4455 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4456 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4457 window->master inbound window->master LAW->the ucode address in
4458 master's memory space.
4460 Building the Software:
4461 ======================
4463 Building U-Boot has been tested in several native build environments
4464 and in many different cross environments. Of course we cannot support
4465 all possibly existing versions of cross development tools in all
4466 (potentially obsolete) versions. In case of tool chain problems we
4467 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4468 which is extensively used to build and test U-Boot.
4470 If you are not using a native environment, it is assumed that you
4471 have GNU cross compiling tools available in your path. In this case,
4472 you must set the environment variable CROSS_COMPILE in your shell.
4473 Note that no changes to the Makefile or any other source files are
4474 necessary. For example using the ELDK on a 4xx CPU, please enter:
4476 $ CROSS_COMPILE=ppc_4xx-
4477 $ export CROSS_COMPILE
4479 Note: If you wish to generate Windows versions of the utilities in
4480 the tools directory you can use the MinGW toolchain
4481 (http://www.mingw.org). Set your HOST tools to the MinGW
4482 toolchain and execute 'make tools'. For example:
4484 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4486 Binaries such as tools/mkimage.exe will be created which can
4487 be executed on computers running Windows.
4489 U-Boot is intended to be simple to build. After installing the
4490 sources you must configure U-Boot for one specific board type. This
4495 where "NAME_config" is the name of one of the existing configu-
4496 rations; see boards.cfg for supported names.
4498 Note: for some board special configuration names may exist; check if
4499 additional information is available from the board vendor; for
4500 instance, the TQM823L systems are available without (standard)
4501 or with LCD support. You can select such additional "features"
4502 when choosing the configuration, i. e.
4505 - will configure for a plain TQM823L, i. e. no LCD support
4507 make TQM823L_LCD_config
4508 - will configure for a TQM823L with U-Boot console on LCD
4513 Finally, type "make all", and you should get some working U-Boot
4514 images ready for download to / installation on your system:
4516 - "u-boot.bin" is a raw binary image
4517 - "u-boot" is an image in ELF binary format
4518 - "u-boot.srec" is in Motorola S-Record format
4520 By default the build is performed locally and the objects are saved
4521 in the source directory. One of the two methods can be used to change
4522 this behavior and build U-Boot to some external directory:
4524 1. Add O= to the make command line invocations:
4526 make O=/tmp/build distclean
4527 make O=/tmp/build NAME_config
4528 make O=/tmp/build all
4530 2. Set environment variable BUILD_DIR to point to the desired location:
4532 export BUILD_DIR=/tmp/build
4537 Note that the command line "O=" setting overrides the BUILD_DIR environment
4541 Please be aware that the Makefiles assume you are using GNU make, so
4542 for instance on NetBSD you might need to use "gmake" instead of
4546 If the system board that you have is not listed, then you will need
4547 to port U-Boot to your hardware platform. To do this, follow these
4550 1. Add a new configuration option for your board to the toplevel
4551 "boards.cfg" file, using the existing entries as examples.
4552 Follow the instructions there to keep the boards in order.
4553 2. Create a new directory to hold your board specific code. Add any
4554 files you need. In your board directory, you will need at least
4555 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4556 3. Create a new configuration file "include/configs/<board>.h" for
4558 3. If you're porting U-Boot to a new CPU, then also create a new
4559 directory to hold your CPU specific code. Add any files you need.
4560 4. Run "make <board>_config" with your new name.
4561 5. Type "make", and you should get a working "u-boot.srec" file
4562 to be installed on your target system.
4563 6. Debug and solve any problems that might arise.
4564 [Of course, this last step is much harder than it sounds.]
4567 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4568 ==============================================================
4570 If you have modified U-Boot sources (for instance added a new board
4571 or support for new devices, a new CPU, etc.) you are expected to
4572 provide feedback to the other developers. The feedback normally takes
4573 the form of a "patch", i. e. a context diff against a certain (latest
4574 official or latest in the git repository) version of U-Boot sources.
4576 But before you submit such a patch, please verify that your modifi-
4577 cation did not break existing code. At least make sure that *ALL* of
4578 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4579 just run the "MAKEALL" script, which will configure and build U-Boot
4580 for ALL supported system. Be warned, this will take a while. You can
4581 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4582 environment variable to the script, i. e. to use the ELDK cross tools
4585 CROSS_COMPILE=ppc_8xx- MAKEALL
4587 or to build on a native PowerPC system you can type
4589 CROSS_COMPILE=' ' MAKEALL
4591 When using the MAKEALL script, the default behaviour is to build
4592 U-Boot in the source directory. This location can be changed by
4593 setting the BUILD_DIR environment variable. Also, for each target
4594 built, the MAKEALL script saves two log files (<target>.ERR and
4595 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4596 location can be changed by setting the MAKEALL_LOGDIR environment
4597 variable. For example:
4599 export BUILD_DIR=/tmp/build
4600 export MAKEALL_LOGDIR=/tmp/log
4601 CROSS_COMPILE=ppc_8xx- MAKEALL
4603 With the above settings build objects are saved in the /tmp/build,
4604 log files are saved in the /tmp/log and the source tree remains clean
4605 during the whole build process.
4608 See also "U-Boot Porting Guide" below.
4611 Monitor Commands - Overview:
4612 ============================
4614 go - start application at address 'addr'
4615 run - run commands in an environment variable
4616 bootm - boot application image from memory
4617 bootp - boot image via network using BootP/TFTP protocol
4618 bootz - boot zImage from memory
4619 tftpboot- boot image via network using TFTP protocol
4620 and env variables "ipaddr" and "serverip"
4621 (and eventually "gatewayip")
4622 tftpput - upload a file via network using TFTP protocol
4623 rarpboot- boot image via network using RARP/TFTP protocol
4624 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4625 loads - load S-Record file over serial line
4626 loadb - load binary file over serial line (kermit mode)
4628 mm - memory modify (auto-incrementing)
4629 nm - memory modify (constant address)
4630 mw - memory write (fill)
4632 cmp - memory compare
4633 crc32 - checksum calculation
4634 i2c - I2C sub-system
4635 sspi - SPI utility commands
4636 base - print or set address offset
4637 printenv- print environment variables
4638 setenv - set environment variables
4639 saveenv - save environment variables to persistent storage
4640 protect - enable or disable FLASH write protection
4641 erase - erase FLASH memory
4642 flinfo - print FLASH memory information
4643 nand - NAND memory operations (see doc/README.nand)
4644 bdinfo - print Board Info structure
4645 iminfo - print header information for application image
4646 coninfo - print console devices and informations
4647 ide - IDE sub-system
4648 loop - infinite loop on address range
4649 loopw - infinite write loop on address range
4650 mtest - simple RAM test
4651 icache - enable or disable instruction cache
4652 dcache - enable or disable data cache
4653 reset - Perform RESET of the CPU
4654 echo - echo args to console
4655 version - print monitor version
4656 help - print online help
4657 ? - alias for 'help'
4660 Monitor Commands - Detailed Description:
4661 ========================================
4665 For now: just type "help <command>".
4668 Environment Variables:
4669 ======================
4671 U-Boot supports user configuration using Environment Variables which
4672 can be made persistent by saving to Flash memory.
4674 Environment Variables are set using "setenv", printed using
4675 "printenv", and saved to Flash using "saveenv". Using "setenv"
4676 without a value can be used to delete a variable from the
4677 environment. As long as you don't save the environment you are
4678 working with an in-memory copy. In case the Flash area containing the
4679 environment is erased by accident, a default environment is provided.
4681 Some configuration options can be set using Environment Variables.
4683 List of environment variables (most likely not complete):
4685 baudrate - see CONFIG_BAUDRATE
4687 bootdelay - see CONFIG_BOOTDELAY
4689 bootcmd - see CONFIG_BOOTCOMMAND
4691 bootargs - Boot arguments when booting an RTOS image
4693 bootfile - Name of the image to load with TFTP
4695 bootm_low - Memory range available for image processing in the bootm
4696 command can be restricted. This variable is given as
4697 a hexadecimal number and defines lowest address allowed
4698 for use by the bootm command. See also "bootm_size"
4699 environment variable. Address defined by "bootm_low" is
4700 also the base of the initial memory mapping for the Linux
4701 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4704 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4705 This variable is given as a hexadecimal number and it
4706 defines the size of the memory region starting at base
4707 address bootm_low that is accessible by the Linux kernel
4708 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4709 as the default value if it is defined, and bootm_size is
4712 bootm_size - Memory range available for image processing in the bootm
4713 command can be restricted. This variable is given as
4714 a hexadecimal number and defines the size of the region
4715 allowed for use by the bootm command. See also "bootm_low"
4716 environment variable.
4718 updatefile - Location of the software update file on a TFTP server, used
4719 by the automatic software update feature. Please refer to
4720 documentation in doc/README.update for more details.
4722 autoload - if set to "no" (any string beginning with 'n'),
4723 "bootp" will just load perform a lookup of the
4724 configuration from the BOOTP server, but not try to
4725 load any image using TFTP
4727 autostart - if set to "yes", an image loaded using the "bootp",
4728 "rarpboot", "tftpboot" or "diskboot" commands will
4729 be automatically started (by internally calling
4732 If set to "no", a standalone image passed to the
4733 "bootm" command will be copied to the load address
4734 (and eventually uncompressed), but NOT be started.
4735 This can be used to load and uncompress arbitrary
4738 fdt_high - if set this restricts the maximum address that the
4739 flattened device tree will be copied into upon boot.
4740 For example, if you have a system with 1 GB memory
4741 at physical address 0x10000000, while Linux kernel
4742 only recognizes the first 704 MB as low memory, you
4743 may need to set fdt_high as 0x3C000000 to have the
4744 device tree blob be copied to the maximum address
4745 of the 704 MB low memory, so that Linux kernel can
4746 access it during the boot procedure.
4748 If this is set to the special value 0xFFFFFFFF then
4749 the fdt will not be copied at all on boot. For this
4750 to work it must reside in writable memory, have
4751 sufficient padding on the end of it for u-boot to
4752 add the information it needs into it, and the memory
4753 must be accessible by the kernel.
4755 fdtcontroladdr- if set this is the address of the control flattened
4756 device tree used by U-Boot when CONFIG_OF_CONTROL is
4759 i2cfast - (PPC405GP|PPC405EP only)
4760 if set to 'y' configures Linux I2C driver for fast
4761 mode (400kHZ). This environment variable is used in
4762 initialization code. So, for changes to be effective
4763 it must be saved and board must be reset.
4765 initrd_high - restrict positioning of initrd images:
4766 If this variable is not set, initrd images will be
4767 copied to the highest possible address in RAM; this
4768 is usually what you want since it allows for
4769 maximum initrd size. If for some reason you want to
4770 make sure that the initrd image is loaded below the
4771 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4772 variable to a value of "no" or "off" or "0".
4773 Alternatively, you can set it to a maximum upper
4774 address to use (U-Boot will still check that it
4775 does not overwrite the U-Boot stack and data).
4777 For instance, when you have a system with 16 MB
4778 RAM, and want to reserve 4 MB from use by Linux,
4779 you can do this by adding "mem=12M" to the value of
4780 the "bootargs" variable. However, now you must make
4781 sure that the initrd image is placed in the first
4782 12 MB as well - this can be done with
4784 setenv initrd_high 00c00000
4786 If you set initrd_high to 0xFFFFFFFF, this is an
4787 indication to U-Boot that all addresses are legal
4788 for the Linux kernel, including addresses in flash
4789 memory. In this case U-Boot will NOT COPY the
4790 ramdisk at all. This may be useful to reduce the
4791 boot time on your system, but requires that this
4792 feature is supported by your Linux kernel.
4794 ipaddr - IP address; needed for tftpboot command
4796 loadaddr - Default load address for commands like "bootp",
4797 "rarpboot", "tftpboot", "loadb" or "diskboot"
4799 loads_echo - see CONFIG_LOADS_ECHO
4801 serverip - TFTP server IP address; needed for tftpboot command
4803 bootretry - see CONFIG_BOOT_RETRY_TIME
4805 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4807 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4809 ethprime - controls which interface is used first.
4811 ethact - controls which interface is currently active.
4812 For example you can do the following
4814 => setenv ethact FEC
4815 => ping 192.168.0.1 # traffic sent on FEC
4816 => setenv ethact SCC
4817 => ping 10.0.0.1 # traffic sent on SCC
4819 ethrotate - When set to "no" U-Boot does not go through all
4820 available network interfaces.
4821 It just stays at the currently selected interface.
4823 netretry - When set to "no" each network operation will
4824 either succeed or fail without retrying.
4825 When set to "once" the network operation will
4826 fail when all the available network interfaces
4827 are tried once without success.
4828 Useful on scripts which control the retry operation
4831 npe_ucode - set load address for the NPE microcode
4833 silent_linux - If set then linux will be told to boot silently, by
4834 changing the console to be empty. If "yes" it will be
4835 made silent. If "no" it will not be made silent. If
4836 unset, then it will be made silent if the U-Boot console
4839 tftpsrcport - If this is set, the value is used for TFTP's
4842 tftpdstport - If this is set, the value is used for TFTP's UDP
4843 destination port instead of the Well Know Port 69.
4845 tftpblocksize - Block size to use for TFTP transfers; if not set,
4846 we use the TFTP server's default block size
4848 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4849 seconds, minimum value is 1000 = 1 second). Defines
4850 when a packet is considered to be lost so it has to
4851 be retransmitted. The default is 5000 = 5 seconds.
4852 Lowering this value may make downloads succeed
4853 faster in networks with high packet loss rates or
4854 with unreliable TFTP servers.
4856 vlan - When set to a value < 4095 the traffic over
4857 Ethernet is encapsulated/received over 802.1q
4860 The following image location variables contain the location of images
4861 used in booting. The "Image" column gives the role of the image and is
4862 not an environment variable name. The other columns are environment
4863 variable names. "File Name" gives the name of the file on a TFTP
4864 server, "RAM Address" gives the location in RAM the image will be
4865 loaded to, and "Flash Location" gives the image's address in NOR
4866 flash or offset in NAND flash.
4868 *Note* - these variables don't have to be defined for all boards, some
4869 boards currenlty use other variables for these purposes, and some
4870 boards use these variables for other purposes.
4872 Image File Name RAM Address Flash Location
4873 ----- --------- ----------- --------------
4874 u-boot u-boot u-boot_addr_r u-boot_addr
4875 Linux kernel bootfile kernel_addr_r kernel_addr
4876 device tree blob fdtfile fdt_addr_r fdt_addr
4877 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4879 The following environment variables may be used and automatically
4880 updated by the network boot commands ("bootp" and "rarpboot"),
4881 depending the information provided by your boot server:
4883 bootfile - see above
4884 dnsip - IP address of your Domain Name Server
4885 dnsip2 - IP address of your secondary Domain Name Server
4886 gatewayip - IP address of the Gateway (Router) to use
4887 hostname - Target hostname
4889 netmask - Subnet Mask
4890 rootpath - Pathname of the root filesystem on the NFS server
4891 serverip - see above
4894 There are two special Environment Variables:
4896 serial# - contains hardware identification information such
4897 as type string and/or serial number
4898 ethaddr - Ethernet address
4900 These variables can be set only once (usually during manufacturing of
4901 the board). U-Boot refuses to delete or overwrite these variables
4902 once they have been set once.
4905 Further special Environment Variables:
4907 ver - Contains the U-Boot version string as printed
4908 with the "version" command. This variable is
4909 readonly (see CONFIG_VERSION_VARIABLE).
4912 Please note that changes to some configuration parameters may take
4913 only effect after the next boot (yes, that's just like Windoze :-).
4916 Callback functions for environment variables:
4917 ---------------------------------------------
4919 For some environment variables, the behavior of u-boot needs to change
4920 when their values are changed. This functionailty allows functions to
4921 be associated with arbitrary variables. On creation, overwrite, or
4922 deletion, the callback will provide the opportunity for some side
4923 effect to happen or for the change to be rejected.
4925 The callbacks are named and associated with a function using the
4926 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4928 These callbacks are associated with variables in one of two ways. The
4929 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4930 in the board configuration to a string that defines a list of
4931 associations. The list must be in the following format:
4933 entry = variable_name[:callback_name]
4936 If the callback name is not specified, then the callback is deleted.
4937 Spaces are also allowed anywhere in the list.
4939 Callbacks can also be associated by defining the ".callbacks" variable
4940 with the same list format above. Any association in ".callbacks" will
4941 override any association in the static list. You can define
4942 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4943 ".callbacks" envirnoment variable in the default or embedded environment.
4946 Command Line Parsing:
4947 =====================
4949 There are two different command line parsers available with U-Boot:
4950 the old "simple" one, and the much more powerful "hush" shell:
4952 Old, simple command line parser:
4953 --------------------------------
4955 - supports environment variables (through setenv / saveenv commands)
4956 - several commands on one line, separated by ';'
4957 - variable substitution using "... ${name} ..." syntax
4958 - special characters ('$', ';') can be escaped by prefixing with '\',
4960 setenv bootcmd bootm \${address}
4961 - You can also escape text by enclosing in single apostrophes, for example:
4962 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4967 - similar to Bourne shell, with control structures like
4968 if...then...else...fi, for...do...done; while...do...done,
4969 until...do...done, ...
4970 - supports environment ("global") variables (through setenv / saveenv
4971 commands) and local shell variables (through standard shell syntax
4972 "name=value"); only environment variables can be used with "run"
4978 (1) If a command line (or an environment variable executed by a "run"
4979 command) contains several commands separated by semicolon, and
4980 one of these commands fails, then the remaining commands will be
4983 (2) If you execute several variables with one call to run (i. e.
4984 calling run with a list of variables as arguments), any failing
4985 command will cause "run" to terminate, i. e. the remaining
4986 variables are not executed.
4988 Note for Redundant Ethernet Interfaces:
4989 =======================================
4991 Some boards come with redundant Ethernet interfaces; U-Boot supports
4992 such configurations and is capable of automatic selection of a
4993 "working" interface when needed. MAC assignment works as follows:
4995 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4996 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4997 "eth1addr" (=>eth1), "eth2addr", ...
4999 If the network interface stores some valid MAC address (for instance
5000 in SROM), this is used as default address if there is NO correspon-
5001 ding setting in the environment; if the corresponding environment
5002 variable is set, this overrides the settings in the card; that means:
5004 o If the SROM has a valid MAC address, and there is no address in the
5005 environment, the SROM's address is used.
5007 o If there is no valid address in the SROM, and a definition in the
5008 environment exists, then the value from the environment variable is
5011 o If both the SROM and the environment contain a MAC address, and
5012 both addresses are the same, this MAC address is used.
5014 o If both the SROM and the environment contain a MAC address, and the
5015 addresses differ, the value from the environment is used and a
5018 o If neither SROM nor the environment contain a MAC address, an error
5021 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5022 will be programmed into hardware as part of the initialization process. This
5023 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5024 The naming convention is as follows:
5025 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5030 U-Boot is capable of booting (and performing other auxiliary operations on)
5031 images in two formats:
5033 New uImage format (FIT)
5034 -----------------------
5036 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5037 to Flattened Device Tree). It allows the use of images with multiple
5038 components (several kernels, ramdisks, etc.), with contents protected by
5039 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5045 Old image format is based on binary files which can be basically anything,
5046 preceded by a special header; see the definitions in include/image.h for
5047 details; basically, the header defines the following image properties:
5049 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5050 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5051 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5052 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5054 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5055 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5056 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5057 * Compression Type (uncompressed, gzip, bzip2)
5063 The header is marked by a special Magic Number, and both the header
5064 and the data portions of the image are secured against corruption by
5071 Although U-Boot should support any OS or standalone application
5072 easily, the main focus has always been on Linux during the design of
5075 U-Boot includes many features that so far have been part of some
5076 special "boot loader" code within the Linux kernel. Also, any
5077 "initrd" images to be used are no longer part of one big Linux image;
5078 instead, kernel and "initrd" are separate images. This implementation
5079 serves several purposes:
5081 - the same features can be used for other OS or standalone
5082 applications (for instance: using compressed images to reduce the
5083 Flash memory footprint)
5085 - it becomes much easier to port new Linux kernel versions because
5086 lots of low-level, hardware dependent stuff are done by U-Boot
5088 - the same Linux kernel image can now be used with different "initrd"
5089 images; of course this also means that different kernel images can
5090 be run with the same "initrd". This makes testing easier (you don't
5091 have to build a new "zImage.initrd" Linux image when you just
5092 change a file in your "initrd"). Also, a field-upgrade of the
5093 software is easier now.
5099 Porting Linux to U-Boot based systems:
5100 ---------------------------------------
5102 U-Boot cannot save you from doing all the necessary modifications to
5103 configure the Linux device drivers for use with your target hardware
5104 (no, we don't intend to provide a full virtual machine interface to
5107 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5109 Just make sure your machine specific header file (for instance
5110 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5111 Information structure as we define in include/asm-<arch>/u-boot.h,
5112 and make sure that your definition of IMAP_ADDR uses the same value
5113 as your U-Boot configuration in CONFIG_SYS_IMMR.
5116 Configuring the Linux kernel:
5117 -----------------------------
5119 No specific requirements for U-Boot. Make sure you have some root
5120 device (initial ramdisk, NFS) for your target system.
5123 Building a Linux Image:
5124 -----------------------
5126 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5127 not used. If you use recent kernel source, a new build target
5128 "uImage" will exist which automatically builds an image usable by
5129 U-Boot. Most older kernels also have support for a "pImage" target,
5130 which was introduced for our predecessor project PPCBoot and uses a
5131 100% compatible format.
5140 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5141 encapsulate a compressed Linux kernel image with header information,
5142 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5144 * build a standard "vmlinux" kernel image (in ELF binary format):
5146 * convert the kernel into a raw binary image:
5148 ${CROSS_COMPILE}-objcopy -O binary \
5149 -R .note -R .comment \
5150 -S vmlinux linux.bin
5152 * compress the binary image:
5156 * package compressed binary image for U-Boot:
5158 mkimage -A ppc -O linux -T kernel -C gzip \
5159 -a 0 -e 0 -n "Linux Kernel Image" \
5160 -d linux.bin.gz uImage
5163 The "mkimage" tool can also be used to create ramdisk images for use
5164 with U-Boot, either separated from the Linux kernel image, or
5165 combined into one file. "mkimage" encapsulates the images with a 64
5166 byte header containing information about target architecture,
5167 operating system, image type, compression method, entry points, time
5168 stamp, CRC32 checksums, etc.
5170 "mkimage" can be called in two ways: to verify existing images and
5171 print the header information, or to build new images.
5173 In the first form (with "-l" option) mkimage lists the information
5174 contained in the header of an existing U-Boot image; this includes
5175 checksum verification:
5177 tools/mkimage -l image
5178 -l ==> list image header information
5180 The second form (with "-d" option) is used to build a U-Boot image
5181 from a "data file" which is used as image payload:
5183 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5184 -n name -d data_file image
5185 -A ==> set architecture to 'arch'
5186 -O ==> set operating system to 'os'
5187 -T ==> set image type to 'type'
5188 -C ==> set compression type 'comp'
5189 -a ==> set load address to 'addr' (hex)
5190 -e ==> set entry point to 'ep' (hex)
5191 -n ==> set image name to 'name'
5192 -d ==> use image data from 'datafile'
5194 Right now, all Linux kernels for PowerPC systems use the same load
5195 address (0x00000000), but the entry point address depends on the
5198 - 2.2.x kernels have the entry point at 0x0000000C,
5199 - 2.3.x and later kernels have the entry point at 0x00000000.
5201 So a typical call to build a U-Boot image would read:
5203 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5204 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5205 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5206 > examples/uImage.TQM850L
5207 Image Name: 2.4.4 kernel for TQM850L
5208 Created: Wed Jul 19 02:34:59 2000
5209 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5210 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5211 Load Address: 0x00000000
5212 Entry Point: 0x00000000
5214 To verify the contents of the image (or check for corruption):
5216 -> tools/mkimage -l examples/uImage.TQM850L
5217 Image Name: 2.4.4 kernel for TQM850L
5218 Created: Wed Jul 19 02:34:59 2000
5219 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5220 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5221 Load Address: 0x00000000
5222 Entry Point: 0x00000000
5224 NOTE: for embedded systems where boot time is critical you can trade
5225 speed for memory and install an UNCOMPRESSED image instead: this
5226 needs more space in Flash, but boots much faster since it does not
5227 need to be uncompressed:
5229 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5230 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5231 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5232 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5233 > examples/uImage.TQM850L-uncompressed
5234 Image Name: 2.4.4 kernel for TQM850L
5235 Created: Wed Jul 19 02:34:59 2000
5236 Image Type: PowerPC Linux Kernel Image (uncompressed)
5237 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5238 Load Address: 0x00000000
5239 Entry Point: 0x00000000
5242 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5243 when your kernel is intended to use an initial ramdisk:
5245 -> tools/mkimage -n 'Simple Ramdisk Image' \
5246 > -A ppc -O linux -T ramdisk -C gzip \
5247 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5248 Image Name: Simple Ramdisk Image
5249 Created: Wed Jan 12 14:01:50 2000
5250 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5251 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5252 Load Address: 0x00000000
5253 Entry Point: 0x00000000
5256 Installing a Linux Image:
5257 -------------------------
5259 To downloading a U-Boot image over the serial (console) interface,
5260 you must convert the image to S-Record format:
5262 objcopy -I binary -O srec examples/image examples/image.srec
5264 The 'objcopy' does not understand the information in the U-Boot
5265 image header, so the resulting S-Record file will be relative to
5266 address 0x00000000. To load it to a given address, you need to
5267 specify the target address as 'offset' parameter with the 'loads'
5270 Example: install the image to address 0x40100000 (which on the
5271 TQM8xxL is in the first Flash bank):
5273 => erase 40100000 401FFFFF
5279 ## Ready for S-Record download ...
5280 ~>examples/image.srec
5281 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5283 15989 15990 15991 15992
5284 [file transfer complete]
5286 ## Start Addr = 0x00000000
5289 You can check the success of the download using the 'iminfo' command;
5290 this includes a checksum verification so you can be sure no data
5291 corruption happened:
5295 ## Checking Image at 40100000 ...
5296 Image Name: 2.2.13 for initrd on TQM850L
5297 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5298 Data Size: 335725 Bytes = 327 kB = 0 MB
5299 Load Address: 00000000
5300 Entry Point: 0000000c
5301 Verifying Checksum ... OK
5307 The "bootm" command is used to boot an application that is stored in
5308 memory (RAM or Flash). In case of a Linux kernel image, the contents
5309 of the "bootargs" environment variable is passed to the kernel as
5310 parameters. You can check and modify this variable using the
5311 "printenv" and "setenv" commands:
5314 => printenv bootargs
5315 bootargs=root=/dev/ram
5317 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5319 => printenv bootargs
5320 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5323 ## Booting Linux kernel at 40020000 ...
5324 Image Name: 2.2.13 for NFS on TQM850L
5325 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5326 Data Size: 381681 Bytes = 372 kB = 0 MB
5327 Load Address: 00000000
5328 Entry Point: 0000000c
5329 Verifying Checksum ... OK
5330 Uncompressing Kernel Image ... OK
5331 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
5332 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5333 time_init: decrementer frequency = 187500000/60
5334 Calibrating delay loop... 49.77 BogoMIPS
5335 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5338 If you want to boot a Linux kernel with initial RAM disk, you pass
5339 the memory addresses of both the kernel and the initrd image (PPBCOOT
5340 format!) to the "bootm" command:
5342 => imi 40100000 40200000
5344 ## Checking Image at 40100000 ...
5345 Image Name: 2.2.13 for initrd on TQM850L
5346 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5347 Data Size: 335725 Bytes = 327 kB = 0 MB
5348 Load Address: 00000000
5349 Entry Point: 0000000c
5350 Verifying Checksum ... OK
5352 ## Checking Image at 40200000 ...
5353 Image Name: Simple Ramdisk Image
5354 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5355 Data Size: 566530 Bytes = 553 kB = 0 MB
5356 Load Address: 00000000
5357 Entry Point: 00000000
5358 Verifying Checksum ... OK
5360 => bootm 40100000 40200000
5361 ## Booting Linux kernel at 40100000 ...
5362 Image Name: 2.2.13 for initrd on TQM850L
5363 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5364 Data Size: 335725 Bytes = 327 kB = 0 MB
5365 Load Address: 00000000
5366 Entry Point: 0000000c
5367 Verifying Checksum ... OK
5368 Uncompressing Kernel Image ... OK
5369 ## Loading RAMDisk Image at 40200000 ...
5370 Image Name: Simple Ramdisk Image
5371 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5372 Data Size: 566530 Bytes = 553 kB = 0 MB
5373 Load Address: 00000000
5374 Entry Point: 00000000
5375 Verifying Checksum ... OK
5376 Loading Ramdisk ... OK
5377 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
5378 Boot arguments: root=/dev/ram
5379 time_init: decrementer frequency = 187500000/60
5380 Calibrating delay loop... 49.77 BogoMIPS
5382 RAMDISK: Compressed image found at block 0
5383 VFS: Mounted root (ext2 filesystem).
5387 Boot Linux and pass a flat device tree:
5390 First, U-Boot must be compiled with the appropriate defines. See the section
5391 titled "Linux Kernel Interface" above for a more in depth explanation. The
5392 following is an example of how to start a kernel and pass an updated
5398 oft=oftrees/mpc8540ads.dtb
5399 => tftp $oftaddr $oft
5400 Speed: 1000, full duplex
5402 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5403 Filename 'oftrees/mpc8540ads.dtb'.
5404 Load address: 0x300000
5407 Bytes transferred = 4106 (100a hex)
5408 => tftp $loadaddr $bootfile
5409 Speed: 1000, full duplex
5411 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5413 Load address: 0x200000
5414 Loading:############
5416 Bytes transferred = 1029407 (fb51f hex)
5421 => bootm $loadaddr - $oftaddr
5422 ## Booting image at 00200000 ...
5423 Image Name: Linux-2.6.17-dirty
5424 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5425 Data Size: 1029343 Bytes = 1005.2 kB
5426 Load Address: 00000000
5427 Entry Point: 00000000
5428 Verifying Checksum ... OK
5429 Uncompressing Kernel Image ... OK
5430 Booting using flat device tree at 0x300000
5431 Using MPC85xx ADS machine description
5432 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5436 More About U-Boot Image Types:
5437 ------------------------------
5439 U-Boot supports the following image types:
5441 "Standalone Programs" are directly runnable in the environment
5442 provided by U-Boot; it is expected that (if they behave
5443 well) you can continue to work in U-Boot after return from
5444 the Standalone Program.
5445 "OS Kernel Images" are usually images of some Embedded OS which
5446 will take over control completely. Usually these programs
5447 will install their own set of exception handlers, device
5448 drivers, set up the MMU, etc. - this means, that you cannot
5449 expect to re-enter U-Boot except by resetting the CPU.
5450 "RAMDisk Images" are more or less just data blocks, and their
5451 parameters (address, size) are passed to an OS kernel that is
5453 "Multi-File Images" contain several images, typically an OS
5454 (Linux) kernel image and one or more data images like
5455 RAMDisks. This construct is useful for instance when you want
5456 to boot over the network using BOOTP etc., where the boot
5457 server provides just a single image file, but you want to get
5458 for instance an OS kernel and a RAMDisk image.
5460 "Multi-File Images" start with a list of image sizes, each
5461 image size (in bytes) specified by an "uint32_t" in network
5462 byte order. This list is terminated by an "(uint32_t)0".
5463 Immediately after the terminating 0 follow the images, one by
5464 one, all aligned on "uint32_t" boundaries (size rounded up to
5465 a multiple of 4 bytes).
5467 "Firmware Images" are binary images containing firmware (like
5468 U-Boot or FPGA images) which usually will be programmed to
5471 "Script files" are command sequences that will be executed by
5472 U-Boot's command interpreter; this feature is especially
5473 useful when you configure U-Boot to use a real shell (hush)
5474 as command interpreter.
5476 Booting the Linux zImage:
5477 -------------------------
5479 On some platforms, it's possible to boot Linux zImage. This is done
5480 using the "bootz" command. The syntax of "bootz" command is the same
5481 as the syntax of "bootm" command.
5483 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5484 kernel with raw initrd images. The syntax is slightly different, the
5485 address of the initrd must be augmented by it's size, in the following
5486 format: "<initrd addres>:<initrd size>".
5492 One of the features of U-Boot is that you can dynamically load and
5493 run "standalone" applications, which can use some resources of
5494 U-Boot like console I/O functions or interrupt services.
5496 Two simple examples are included with the sources:
5501 'examples/hello_world.c' contains a small "Hello World" Demo
5502 application; it is automatically compiled when you build U-Boot.
5503 It's configured to run at address 0x00040004, so you can play with it
5507 ## Ready for S-Record download ...
5508 ~>examples/hello_world.srec
5509 1 2 3 4 5 6 7 8 9 10 11 ...
5510 [file transfer complete]
5512 ## Start Addr = 0x00040004
5514 => go 40004 Hello World! This is a test.
5515 ## Starting application at 0x00040004 ...
5526 Hit any key to exit ...
5528 ## Application terminated, rc = 0x0
5530 Another example, which demonstrates how to register a CPM interrupt
5531 handler with the U-Boot code, can be found in 'examples/timer.c'.
5532 Here, a CPM timer is set up to generate an interrupt every second.
5533 The interrupt service routine is trivial, just printing a '.'
5534 character, but this is just a demo program. The application can be
5535 controlled by the following keys:
5537 ? - print current values og the CPM Timer registers
5538 b - enable interrupts and start timer
5539 e - stop timer and disable interrupts
5540 q - quit application
5543 ## Ready for S-Record download ...
5544 ~>examples/timer.srec
5545 1 2 3 4 5 6 7 8 9 10 11 ...
5546 [file transfer complete]
5548 ## Start Addr = 0x00040004
5551 ## Starting application at 0x00040004 ...
5554 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5557 [q, b, e, ?] Set interval 1000000 us
5560 [q, b, e, ?] ........
5561 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5564 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5567 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5570 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5572 [q, b, e, ?] ...Stopping timer
5574 [q, b, e, ?] ## Application terminated, rc = 0x0
5580 Over time, many people have reported problems when trying to use the
5581 "minicom" terminal emulation program for serial download. I (wd)
5582 consider minicom to be broken, and recommend not to use it. Under
5583 Unix, I recommend to use C-Kermit for general purpose use (and
5584 especially for kermit binary protocol download ("loadb" command), and
5585 use "cu" for S-Record download ("loads" command). See
5586 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5587 for help with kermit.
5590 Nevertheless, if you absolutely want to use it try adding this
5591 configuration to your "File transfer protocols" section:
5593 Name Program Name U/D FullScr IO-Red. Multi
5594 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5595 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5601 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5602 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5604 Building requires a cross environment; it is known to work on
5605 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5606 need gmake since the Makefiles are not compatible with BSD make).
5607 Note that the cross-powerpc package does not install include files;
5608 attempting to build U-Boot will fail because <machine/ansi.h> is
5609 missing. This file has to be installed and patched manually:
5611 # cd /usr/pkg/cross/powerpc-netbsd/include
5613 # ln -s powerpc machine
5614 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5615 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5617 Native builds *don't* work due to incompatibilities between native
5618 and U-Boot include files.
5620 Booting assumes that (the first part of) the image booted is a
5621 stage-2 loader which in turn loads and then invokes the kernel
5622 proper. Loader sources will eventually appear in the NetBSD source
5623 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5624 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5627 Implementation Internals:
5628 =========================
5630 The following is not intended to be a complete description of every
5631 implementation detail. However, it should help to understand the
5632 inner workings of U-Boot and make it easier to port it to custom
5636 Initial Stack, Global Data:
5637 ---------------------------
5639 The implementation of U-Boot is complicated by the fact that U-Boot
5640 starts running out of ROM (flash memory), usually without access to
5641 system RAM (because the memory controller is not initialized yet).
5642 This means that we don't have writable Data or BSS segments, and BSS
5643 is not initialized as zero. To be able to get a C environment working
5644 at all, we have to allocate at least a minimal stack. Implementation
5645 options for this are defined and restricted by the CPU used: Some CPU
5646 models provide on-chip memory (like the IMMR area on MPC8xx and
5647 MPC826x processors), on others (parts of) the data cache can be
5648 locked as (mis-) used as memory, etc.
5650 Chris Hallinan posted a good summary of these issues to the
5651 U-Boot mailing list:
5653 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5654 From: "Chris Hallinan" <clh@net1plus.com>
5655 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5658 Correct me if I'm wrong, folks, but the way I understand it
5659 is this: Using DCACHE as initial RAM for Stack, etc, does not
5660 require any physical RAM backing up the cache. The cleverness
5661 is that the cache is being used as a temporary supply of
5662 necessary storage before the SDRAM controller is setup. It's
5663 beyond the scope of this list to explain the details, but you
5664 can see how this works by studying the cache architecture and
5665 operation in the architecture and processor-specific manuals.
5667 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5668 is another option for the system designer to use as an
5669 initial stack/RAM area prior to SDRAM being available. Either
5670 option should work for you. Using CS 4 should be fine if your
5671 board designers haven't used it for something that would
5672 cause you grief during the initial boot! It is frequently not
5675 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5676 with your processor/board/system design. The default value
5677 you will find in any recent u-boot distribution in
5678 walnut.h should work for you. I'd set it to a value larger
5679 than your SDRAM module. If you have a 64MB SDRAM module, set
5680 it above 400_0000. Just make sure your board has no resources
5681 that are supposed to respond to that address! That code in
5682 start.S has been around a while and should work as is when
5683 you get the config right.
5688 It is essential to remember this, since it has some impact on the C
5689 code for the initialization procedures:
5691 * Initialized global data (data segment) is read-only. Do not attempt
5694 * Do not use any uninitialized global data (or implicitely initialized
5695 as zero data - BSS segment) at all - this is undefined, initiali-
5696 zation is performed later (when relocating to RAM).
5698 * Stack space is very limited. Avoid big data buffers or things like
5701 Having only the stack as writable memory limits means we cannot use
5702 normal global data to share information beween the code. But it
5703 turned out that the implementation of U-Boot can be greatly
5704 simplified by making a global data structure (gd_t) available to all
5705 functions. We could pass a pointer to this data as argument to _all_
5706 functions, but this would bloat the code. Instead we use a feature of
5707 the GCC compiler (Global Register Variables) to share the data: we
5708 place a pointer (gd) to the global data into a register which we
5709 reserve for this purpose.
5711 When choosing a register for such a purpose we are restricted by the
5712 relevant (E)ABI specifications for the current architecture, and by
5713 GCC's implementation.
5715 For PowerPC, the following registers have specific use:
5717 R2: reserved for system use
5718 R3-R4: parameter passing and return values
5719 R5-R10: parameter passing
5720 R13: small data area pointer
5724 (U-Boot also uses R12 as internal GOT pointer. r12
5725 is a volatile register so r12 needs to be reset when
5726 going back and forth between asm and C)
5728 ==> U-Boot will use R2 to hold a pointer to the global data
5730 Note: on PPC, we could use a static initializer (since the
5731 address of the global data structure is known at compile time),
5732 but it turned out that reserving a register results in somewhat
5733 smaller code - although the code savings are not that big (on
5734 average for all boards 752 bytes for the whole U-Boot image,
5735 624 text + 127 data).
5737 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5738 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5740 ==> U-Boot will use P3 to hold a pointer to the global data
5742 On ARM, the following registers are used:
5744 R0: function argument word/integer result
5745 R1-R3: function argument word
5746 R9: platform specific
5747 R10: stack limit (used only if stack checking is enabled)
5748 R11: argument (frame) pointer
5749 R12: temporary workspace
5752 R15: program counter
5754 ==> U-Boot will use R9 to hold a pointer to the global data
5756 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5758 On Nios II, the ABI is documented here:
5759 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5761 ==> U-Boot will use gp to hold a pointer to the global data
5763 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5764 to access small data sections, so gp is free.
5766 On NDS32, the following registers are used:
5768 R0-R1: argument/return
5770 R15: temporary register for assembler
5771 R16: trampoline register
5772 R28: frame pointer (FP)
5773 R29: global pointer (GP)
5774 R30: link register (LP)
5775 R31: stack pointer (SP)
5776 PC: program counter (PC)
5778 ==> U-Boot will use R10 to hold a pointer to the global data
5780 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5781 or current versions of GCC may "optimize" the code too much.
5786 U-Boot runs in system state and uses physical addresses, i.e. the
5787 MMU is not used either for address mapping nor for memory protection.
5789 The available memory is mapped to fixed addresses using the memory
5790 controller. In this process, a contiguous block is formed for each
5791 memory type (Flash, SDRAM, SRAM), even when it consists of several
5792 physical memory banks.
5794 U-Boot is installed in the first 128 kB of the first Flash bank (on
5795 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5796 booting and sizing and initializing DRAM, the code relocates itself
5797 to the upper end of DRAM. Immediately below the U-Boot code some
5798 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5799 configuration setting]. Below that, a structure with global Board
5800 Info data is placed, followed by the stack (growing downward).
5802 Additionally, some exception handler code is copied to the low 8 kB
5803 of DRAM (0x00000000 ... 0x00001FFF).
5805 So a typical memory configuration with 16 MB of DRAM could look like
5808 0x0000 0000 Exception Vector code
5811 0x0000 2000 Free for Application Use
5817 0x00FB FF20 Monitor Stack (Growing downward)
5818 0x00FB FFAC Board Info Data and permanent copy of global data
5819 0x00FC 0000 Malloc Arena
5822 0x00FE 0000 RAM Copy of Monitor Code
5823 ... eventually: LCD or video framebuffer
5824 ... eventually: pRAM (Protected RAM - unchanged by reset)
5825 0x00FF FFFF [End of RAM]
5828 System Initialization:
5829 ----------------------
5831 In the reset configuration, U-Boot starts at the reset entry point
5832 (on most PowerPC systems at address 0x00000100). Because of the reset
5833 configuration for CS0# this is a mirror of the onboard Flash memory.
5834 To be able to re-map memory U-Boot then jumps to its link address.
5835 To be able to implement the initialization code in C, a (small!)
5836 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5837 which provide such a feature like MPC8xx or MPC8260), or in a locked
5838 part of the data cache. After that, U-Boot initializes the CPU core,
5839 the caches and the SIU.
5841 Next, all (potentially) available memory banks are mapped using a
5842 preliminary mapping. For example, we put them on 512 MB boundaries
5843 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5844 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5845 programmed for SDRAM access. Using the temporary configuration, a
5846 simple memory test is run that determines the size of the SDRAM
5849 When there is more than one SDRAM bank, and the banks are of
5850 different size, the largest is mapped first. For equal size, the first
5851 bank (CS2#) is mapped first. The first mapping is always for address
5852 0x00000000, with any additional banks following immediately to create
5853 contiguous memory starting from 0.
5855 Then, the monitor installs itself at the upper end of the SDRAM area
5856 and allocates memory for use by malloc() and for the global Board
5857 Info data; also, the exception vector code is copied to the low RAM
5858 pages, and the final stack is set up.
5860 Only after this relocation will you have a "normal" C environment;
5861 until that you are restricted in several ways, mostly because you are
5862 running from ROM, and because the code will have to be relocated to a
5866 U-Boot Porting Guide:
5867 ----------------------
5869 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5873 int main(int argc, char *argv[])
5875 sighandler_t no_more_time;
5877 signal(SIGALRM, no_more_time);
5878 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5880 if (available_money > available_manpower) {
5881 Pay consultant to port U-Boot;
5885 Download latest U-Boot source;
5887 Subscribe to u-boot mailing list;
5890 email("Hi, I am new to U-Boot, how do I get started?");
5893 Read the README file in the top level directory;
5894 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5895 Read applicable doc/*.README;
5896 Read the source, Luke;
5897 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5900 if (available_money > toLocalCurrency ($2500))
5903 Add a lot of aggravation and time;
5905 if (a similar board exists) { /* hopefully... */
5906 cp -a board/<similar> board/<myboard>
5907 cp include/configs/<similar>.h include/configs/<myboard>.h
5909 Create your own board support subdirectory;
5910 Create your own board include/configs/<myboard>.h file;
5912 Edit new board/<myboard> files
5913 Edit new include/configs/<myboard>.h
5918 Add / modify source code;
5922 email("Hi, I am having problems...");
5924 Send patch file to the U-Boot email list;
5925 if (reasonable critiques)
5926 Incorporate improvements from email list code review;
5928 Defend code as written;
5934 void no_more_time (int sig)
5943 All contributions to U-Boot should conform to the Linux kernel
5944 coding style; see the file "Documentation/CodingStyle" and the script
5945 "scripts/Lindent" in your Linux kernel source directory.
5947 Source files originating from a different project (for example the
5948 MTD subsystem) are generally exempt from these guidelines and are not
5949 reformated to ease subsequent migration to newer versions of those
5952 Please note that U-Boot is implemented in C (and to some small parts in
5953 Assembler); no C++ is used, so please do not use C++ style comments (//)
5956 Please also stick to the following formatting rules:
5957 - remove any trailing white space
5958 - use TAB characters for indentation and vertical alignment, not spaces
5959 - make sure NOT to use DOS '\r\n' line feeds
5960 - do not add more than 2 consecutive empty lines to source files
5961 - do not add trailing empty lines to source files
5963 Submissions which do not conform to the standards may be returned
5964 with a request to reformat the changes.
5970 Since the number of patches for U-Boot is growing, we need to
5971 establish some rules. Submissions which do not conform to these rules
5972 may be rejected, even when they contain important and valuable stuff.
5974 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5976 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5977 see http://lists.denx.de/mailman/listinfo/u-boot
5979 When you send a patch, please include the following information with
5982 * For bug fixes: a description of the bug and how your patch fixes
5983 this bug. Please try to include a way of demonstrating that the
5984 patch actually fixes something.
5986 * For new features: a description of the feature and your
5989 * A CHANGELOG entry as plaintext (separate from the patch)
5991 * For major contributions, your entry to the CREDITS file
5993 * When you add support for a new board, don't forget to add a
5994 maintainer e-mail address to the boards.cfg file, too.
5996 * If your patch adds new configuration options, don't forget to
5997 document these in the README file.
5999 * The patch itself. If you are using git (which is *strongly*
6000 recommended) you can easily generate the patch using the
6001 "git format-patch". If you then use "git send-email" to send it to
6002 the U-Boot mailing list, you will avoid most of the common problems
6003 with some other mail clients.
6005 If you cannot use git, use "diff -purN OLD NEW". If your version of
6006 diff does not support these options, then get the latest version of
6009 The current directory when running this command shall be the parent
6010 directory of the U-Boot source tree (i. e. please make sure that
6011 your patch includes sufficient directory information for the
6014 We prefer patches as plain text. MIME attachments are discouraged,
6015 and compressed attachments must not be used.
6017 * If one logical set of modifications affects or creates several
6018 files, all these changes shall be submitted in a SINGLE patch file.
6020 * Changesets that contain different, unrelated modifications shall be
6021 submitted as SEPARATE patches, one patch per changeset.
6026 * Before sending the patch, run the MAKEALL script on your patched
6027 source tree and make sure that no errors or warnings are reported
6028 for any of the boards.
6030 * Keep your modifications to the necessary minimum: A patch
6031 containing several unrelated changes or arbitrary reformats will be
6032 returned with a request to re-formatting / split it.
6034 * If you modify existing code, make sure that your new code does not
6035 add to the memory footprint of the code ;-) Small is beautiful!
6036 When adding new features, these should compile conditionally only
6037 (using #ifdef), and the resulting code with the new feature
6038 disabled must not need more memory than the old code without your
6041 * Remember that there is a size limit of 100 kB per message on the
6042 u-boot mailing list. Bigger patches will be moderated. If they are
6043 reasonable and not too big, they will be acknowledged. But patches
6044 bigger than the size limit should be avoided.
projects / kernel / u-boot.git / blob