2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 CONFIG_ARM_ERRATA_742230
489 CONFIG_ARM_ERRATA_743622
490 CONFIG_ARM_ERRATA_751472
492 If set, the workarounds for these ARM errata are applied early
493 during U-Boot startup. Note that these options force the
494 workarounds to be applied; no CPU-type/version detection
495 exists, unlike the similar options in the Linux kernel. Do not
496 set these options unless they apply!
498 - Linux Kernel Interface:
501 U-Boot stores all clock information in Hz
502 internally. For binary compatibility with older Linux
503 kernels (which expect the clocks passed in the
504 bd_info data to be in MHz) the environment variable
505 "clocks_in_mhz" can be defined so that U-Boot
506 converts clock data to MHZ before passing it to the
508 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
509 "clocks_in_mhz=1" is automatically included in the
512 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
514 When transferring memsize parameter to linux, some versions
515 expect it to be in bytes, others in MB.
516 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
520 New kernel versions are expecting firmware settings to be
521 passed using flattened device trees (based on open firmware
525 * New libfdt-based support
526 * Adds the "fdt" command
527 * The bootm command automatically updates the fdt
529 OF_CPU - The proper name of the cpus node (only required for
530 MPC512X and MPC5xxx based boards).
531 OF_SOC - The proper name of the soc node (only required for
532 MPC512X and MPC5xxx based boards).
533 OF_TBCLK - The timebase frequency.
534 OF_STDOUT_PATH - The path to the console device
536 boards with QUICC Engines require OF_QE to set UCC MAC
539 CONFIG_OF_BOARD_SETUP
541 Board code has addition modification that it wants to make
542 to the flat device tree before handing it off to the kernel
546 This define fills in the correct boot CPU in the boot
547 param header, the default value is zero if undefined.
551 U-Boot can detect if an IDE device is present or not.
552 If not, and this new config option is activated, U-Boot
553 removes the ATA node from the DTS before booting Linux,
554 so the Linux IDE driver does not probe the device and
555 crash. This is needed for buggy hardware (uc101) where
556 no pull down resistor is connected to the signal IDE5V_DD7.
558 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
560 This setting is mandatory for all boards that have only one
561 machine type and must be used to specify the machine type
562 number as it appears in the ARM machine registry
563 (see http://www.arm.linux.org.uk/developer/machines/).
564 Only boards that have multiple machine types supported
565 in a single configuration file and the machine type is
566 runtime discoverable, do not have to use this setting.
568 - vxWorks boot parameters:
570 bootvx constructs a valid bootline using the following
571 environments variables: bootfile, ipaddr, serverip, hostname.
572 It loads the vxWorks image pointed bootfile.
574 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
575 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
576 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
577 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
579 CONFIG_SYS_VXWORKS_ADD_PARAMS
581 Add it at the end of the bootline. E.g "u=username pw=secret"
583 Note: If a "bootargs" environment is defined, it will overwride
584 the defaults discussed just above.
586 - Cache Configuration:
587 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
588 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
589 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
591 - Cache Configuration for ARM:
592 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
594 CONFIG_SYS_PL310_BASE - Physical base address of PL310
595 controller register space
600 Define this if you want support for Amba PrimeCell PL010 UARTs.
604 Define this if you want support for Amba PrimeCell PL011 UARTs.
608 If you have Amba PrimeCell PL011 UARTs, set this variable to
609 the clock speed of the UARTs.
613 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
614 define this to a list of base addresses for each (supported)
615 port. See e.g. include/configs/versatile.h
617 CONFIG_PL011_SERIAL_RLCR
619 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
620 have separate receive and transmit line control registers. Set
621 this variable to initialize the extra register.
623 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
625 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
626 boot loader that has already initialized the UART. Define this
627 variable to flush the UART at init time.
629 CONFIG_SYS_NS16550_BROKEN_TEMT
631 16550 UART set the Transmitter Empty (TEMT) Bit when all output
632 has finished and the transmitter is totally empty. U-Boot waits
633 for this bit to be set to initialize the serial console. On some
634 broken platforms this bit is not set in SPL making U-Boot to
635 hang while waiting for TEMT. Define this option to avoid it.
639 Depending on board, define exactly one serial port
640 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
641 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
642 console by defining CONFIG_8xx_CONS_NONE
644 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
645 port routines must be defined elsewhere
646 (i.e. serial_init(), serial_getc(), ...)
649 Enables console device for a color framebuffer. Needs following
650 defines (cf. smiLynxEM, i8042)
651 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
653 VIDEO_HW_RECTFILL graphic chip supports
656 VIDEO_HW_BITBLT graphic chip supports
657 bit-blit (cf. smiLynxEM)
658 VIDEO_VISIBLE_COLS visible pixel columns
660 VIDEO_VISIBLE_ROWS visible pixel rows
661 VIDEO_PIXEL_SIZE bytes per pixel
662 VIDEO_DATA_FORMAT graphic data format
663 (0-5, cf. cfb_console.c)
664 VIDEO_FB_ADRS framebuffer address
665 VIDEO_KBD_INIT_FCT keyboard int fct
666 (i.e. i8042_kbd_init())
667 VIDEO_TSTC_FCT test char fct
669 VIDEO_GETC_FCT get char fct
671 CONFIG_CONSOLE_CURSOR cursor drawing on/off
672 (requires blink timer
674 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
675 CONFIG_CONSOLE_TIME display time/date info in
677 (requires CONFIG_CMD_DATE)
678 CONFIG_VIDEO_LOGO display Linux logo in
680 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
681 linux_logo.h for logo.
682 Requires CONFIG_VIDEO_LOGO
683 CONFIG_CONSOLE_EXTRA_INFO
684 additional board info beside
687 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
688 a limited number of ANSI escape sequences (cursor control,
689 erase functions and limited graphics rendition control).
691 When CONFIG_CFB_CONSOLE is defined, video console is
692 default i/o. Serial console can be forced with
693 environment 'console=serial'.
695 When CONFIG_SILENT_CONSOLE is defined, all console
696 messages (by U-Boot and Linux!) can be silenced with
697 the "silent" environment variable. See
698 doc/README.silent for more information.
701 CONFIG_BAUDRATE - in bps
702 Select one of the baudrates listed in
703 CONFIG_SYS_BAUDRATE_TABLE, see below.
704 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
706 - Console Rx buffer length
707 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
708 the maximum receive buffer length for the SMC.
709 This option is actual only for 82xx and 8xx possible.
710 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
711 must be defined, to setup the maximum idle timeout for
714 - Pre-Console Buffer:
715 Prior to the console being initialised (i.e. serial UART
716 initialised etc) all console output is silently discarded.
717 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
718 buffer any console messages prior to the console being
719 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
720 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
721 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
722 bytes are output before the console is initialised, the
723 earlier bytes are discarded.
725 'Sane' compilers will generate smaller code if
726 CONFIG_PRE_CON_BUF_SZ is a power of 2
728 - Safe printf() functions
729 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
730 the printf() functions. These are defined in
731 include/vsprintf.h and include snprintf(), vsnprintf() and
732 so on. Code size increase is approximately 300-500 bytes.
733 If this option is not given then these functions will
734 silently discard their buffer size argument - this means
735 you are not getting any overflow checking in this case.
737 - Boot Delay: CONFIG_BOOTDELAY - in seconds
738 Delay before automatically booting the default image;
739 set to -1 to disable autoboot.
740 set to -2 to autoboot with no delay and not check for abort
741 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
743 See doc/README.autoboot for these options that
744 work with CONFIG_BOOTDELAY. None are required.
745 CONFIG_BOOT_RETRY_TIME
746 CONFIG_BOOT_RETRY_MIN
747 CONFIG_AUTOBOOT_KEYED
748 CONFIG_AUTOBOOT_PROMPT
749 CONFIG_AUTOBOOT_DELAY_STR
750 CONFIG_AUTOBOOT_STOP_STR
751 CONFIG_AUTOBOOT_DELAY_STR2
752 CONFIG_AUTOBOOT_STOP_STR2
753 CONFIG_ZERO_BOOTDELAY_CHECK
754 CONFIG_RESET_TO_RETRY
758 Only needed when CONFIG_BOOTDELAY is enabled;
759 define a command string that is automatically executed
760 when no character is read on the console interface
761 within "Boot Delay" after reset.
764 This can be used to pass arguments to the bootm
765 command. The value of CONFIG_BOOTARGS goes into the
766 environment value "bootargs".
768 CONFIG_RAMBOOT and CONFIG_NFSBOOT
769 The value of these goes into the environment as
770 "ramboot" and "nfsboot" respectively, and can be used
771 as a convenience, when switching between booting from
777 When this option is #defined, the existence of the
778 environment variable "preboot" will be checked
779 immediately before starting the CONFIG_BOOTDELAY
780 countdown and/or running the auto-boot command resp.
781 entering interactive mode.
783 This feature is especially useful when "preboot" is
784 automatically generated or modified. For an example
785 see the LWMON board specific code: here "preboot" is
786 modified when the user holds down a certain
787 combination of keys on the (special) keyboard when
790 - Serial Download Echo Mode:
792 If defined to 1, all characters received during a
793 serial download (using the "loads" command) are
794 echoed back. This might be needed by some terminal
795 emulations (like "cu"), but may as well just take
796 time on others. This setting #define's the initial
797 value of the "loads_echo" environment variable.
799 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
801 Select one of the baudrates listed in
802 CONFIG_SYS_BAUDRATE_TABLE, see below.
805 Monitor commands can be included or excluded
806 from the build by using the #include files
807 <config_cmd_all.h> and #undef'ing unwanted
808 commands, or using <config_cmd_default.h>
809 and augmenting with additional #define's
812 The default command configuration includes all commands
813 except those marked below with a "*".
815 CONFIG_CMD_ASKENV * ask for env variable
816 CONFIG_CMD_BDI bdinfo
817 CONFIG_CMD_BEDBUG * Include BedBug Debugger
818 CONFIG_CMD_BMP * BMP support
819 CONFIG_CMD_BSP * Board specific commands
820 CONFIG_CMD_BOOTD bootd
821 CONFIG_CMD_CACHE * icache, dcache
822 CONFIG_CMD_CONSOLE coninfo
823 CONFIG_CMD_CRC32 * crc32
824 CONFIG_CMD_DATE * support for RTC, date/time...
825 CONFIG_CMD_DHCP * DHCP support
826 CONFIG_CMD_DIAG * Diagnostics
827 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
828 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
829 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
830 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
831 CONFIG_CMD_DTT * Digital Therm and Thermostat
832 CONFIG_CMD_ECHO echo arguments
833 CONFIG_CMD_EDITENV edit env variable
834 CONFIG_CMD_EEPROM * EEPROM read/write support
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
837 CONFIG_CMD_ENV_FLAGS * display details about env flags
838 CONFIG_CMD_EXPORTENV * export the environment
839 CONFIG_CMD_EXT2 * ext2 command support
840 CONFIG_CMD_EXT4 * ext4 command support
841 CONFIG_CMD_SAVEENV saveenv
842 CONFIG_CMD_FDC * Floppy Disk Support
843 CONFIG_CMD_FAT * FAT command support
844 CONFIG_CMD_FDOS * Dos diskette Support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GETTIME * Get time since boot
848 CONFIG_CMD_GO * the 'go' command (exec code)
849 CONFIG_CMD_GREPENV * search environment
850 CONFIG_CMD_HASH * calculate hash / digest
851 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
852 CONFIG_CMD_I2C * I2C serial bus support
853 CONFIG_CMD_IDE * IDE harddisk support
854 CONFIG_CMD_IMI iminfo
855 CONFIG_CMD_IMLS List all images found in NOR flash
856 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
857 CONFIG_CMD_IMMAP * IMMR dump support
858 CONFIG_CMD_IMPORTENV * import an environment
859 CONFIG_CMD_INI * import data from an ini file into the env
860 CONFIG_CMD_IRQ * irqinfo
861 CONFIG_CMD_ITEST Integer/string test of 2 values
862 CONFIG_CMD_JFFS2 * JFFS2 Support
863 CONFIG_CMD_KGDB * kgdb
864 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
865 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
867 CONFIG_CMD_LOADB loadb
868 CONFIG_CMD_LOADS loads
869 CONFIG_CMD_MD5SUM print md5 message digest
870 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
871 CONFIG_CMD_MEMINFO * Display detailed memory information
872 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
874 CONFIG_CMD_MEMTEST mtest
875 CONFIG_CMD_MISC Misc functions like sleep etc
876 CONFIG_CMD_MMC * MMC memory mapped support
877 CONFIG_CMD_MII * MII utility commands
878 CONFIG_CMD_MTDPARTS * MTD partition support
879 CONFIG_CMD_NAND * NAND support
880 CONFIG_CMD_NET bootp, tftpboot, rarpboot
881 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
882 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
883 CONFIG_CMD_PCI * pciinfo
884 CONFIG_CMD_PCMCIA * PCMCIA support
885 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
887 CONFIG_CMD_PORTIO * Port I/O
888 CONFIG_CMD_READ * Read raw data from partition
889 CONFIG_CMD_REGINFO * Register dump
890 CONFIG_CMD_RUN run command in env variable
891 CONFIG_CMD_SANDBOX * sb command to access sandbox features
892 CONFIG_CMD_SAVES * save S record dump
893 CONFIG_CMD_SCSI * SCSI Support
894 CONFIG_CMD_SDRAM * print SDRAM configuration information
895 (requires CONFIG_CMD_I2C)
896 CONFIG_CMD_SETGETDCR Support for DCR Register access
898 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
899 CONFIG_CMD_SHA1SUM print sha1 memory digest
900 (requires CONFIG_CMD_MEMORY)
901 CONFIG_CMD_SOURCE "source" command Support
902 CONFIG_CMD_SPI * SPI serial bus support
903 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
904 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
905 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
906 CONFIG_CMD_TIMER * access to the system tick timer
907 CONFIG_CMD_USB * USB support
908 CONFIG_CMD_CDP * Cisco Discover Protocol support
909 CONFIG_CMD_MFSL * Microblaze FSL support
912 EXAMPLE: If you want all functions except of network
913 support you can write:
915 #include "config_cmd_all.h"
916 #undef CONFIG_CMD_NET
919 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
921 Note: Don't enable the "icache" and "dcache" commands
922 (configuration option CONFIG_CMD_CACHE) unless you know
923 what you (and your U-Boot users) are doing. Data
924 cache cannot be enabled on systems like the 8xx or
925 8260 (where accesses to the IMMR region must be
926 uncached), and it cannot be disabled on all other
927 systems where we (mis-) use the data cache to hold an
928 initial stack and some data.
931 XXX - this list needs to get updated!
935 If this variable is defined, U-Boot will use a device tree
936 to configure its devices, instead of relying on statically
937 compiled #defines in the board file. This option is
938 experimental and only available on a few boards. The device
939 tree is available in the global data as gd->fdt_blob.
941 U-Boot needs to get its device tree from somewhere. This can
942 be done using one of the two options below:
945 If this variable is defined, U-Boot will embed a device tree
946 binary in its image. This device tree file should be in the
947 board directory and called <soc>-<board>.dts. The binary file
948 is then picked up in board_init_f() and made available through
949 the global data structure as gd->blob.
952 If this variable is defined, U-Boot will build a device tree
953 binary. It will be called u-boot.dtb. Architecture-specific
954 code will locate it at run-time. Generally this works by:
956 cat u-boot.bin u-boot.dtb >image.bin
958 and in fact, U-Boot does this for you, creating a file called
959 u-boot-dtb.bin which is useful in the common case. You can
960 still use the individual files if you need something more
965 If this variable is defined, it enables watchdog
966 support for the SoC. There must be support in the SoC
967 specific code for a watchdog. For the 8xx and 8260
968 CPUs, the SIU Watchdog feature is enabled in the SYPCR
969 register. When supported for a specific SoC is
970 available, then no further board specific code should
974 When using a watchdog circuitry external to the used
975 SoC, then define this variable and provide board
976 specific code for the "hw_watchdog_reset" function.
979 CONFIG_VERSION_VARIABLE
980 If this variable is defined, an environment variable
981 named "ver" is created by U-Boot showing the U-Boot
982 version as printed by the "version" command.
983 Any change to this variable will be reverted at the
988 When CONFIG_CMD_DATE is selected, the type of the RTC
989 has to be selected, too. Define exactly one of the
992 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
993 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
994 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
995 CONFIG_RTC_MC146818 - use MC146818 RTC
996 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
997 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
998 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
999 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1000 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1001 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1002 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1003 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1006 Note that if the RTC uses I2C, then the I2C interface
1007 must also be configured. See I2C Support, below.
1010 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1011 CONFIG_PCA953X_INFO - enable pca953x info command
1013 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1014 chip-ngpio pairs that tell the PCA953X driver the number of
1015 pins supported by a particular chip.
1017 Note that if the GPIO device uses I2C, then the I2C interface
1018 must also be configured. See I2C Support, below.
1020 - Timestamp Support:
1022 When CONFIG_TIMESTAMP is selected, the timestamp
1023 (date and time) of an image is printed by image
1024 commands like bootm or iminfo. This option is
1025 automatically enabled when you select CONFIG_CMD_DATE .
1027 - Partition Labels (disklabels) Supported:
1028 Zero or more of the following:
1029 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1030 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1031 Intel architecture, USB sticks, etc.
1032 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1033 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1034 bootloader. Note 2TB partition limit; see
1036 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1038 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1039 CONFIG_CMD_SCSI) you must configure support for at
1040 least one non-MTD partition type as well.
1043 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1044 board configurations files but used nowhere!
1046 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1047 be performed by calling the function
1048 ide_set_reset(int reset)
1049 which has to be defined in a board specific file
1054 Set this to enable ATAPI support.
1059 Set this to enable support for disks larger than 137GB
1060 Also look at CONFIG_SYS_64BIT_LBA.
1061 Whithout these , LBA48 support uses 32bit variables and will 'only'
1062 support disks up to 2.1TB.
1064 CONFIG_SYS_64BIT_LBA:
1065 When enabled, makes the IDE subsystem use 64bit sector addresses.
1069 At the moment only there is only support for the
1070 SYM53C8XX SCSI controller; define
1071 CONFIG_SCSI_SYM53C8XX to enable it.
1073 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1074 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1075 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1076 maximum numbers of LUNs, SCSI ID's and target
1078 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1080 The environment variable 'scsidevs' is set to the number of
1081 SCSI devices found during the last scan.
1083 - NETWORK Support (PCI):
1085 Support for Intel 8254x/8257x gigabit chips.
1088 Utility code for direct access to the SPI bus on Intel 8257x.
1089 This does not do anything useful unless you set at least one
1090 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1092 CONFIG_E1000_SPI_GENERIC
1093 Allow generic access to the SPI bus on the Intel 8257x, for
1094 example with the "sspi" command.
1097 Management command for E1000 devices. When used on devices
1098 with SPI support you can reprogram the EEPROM from U-Boot.
1100 CONFIG_E1000_FALLBACK_MAC
1101 default MAC for empty EEPROM after production.
1104 Support for Intel 82557/82559/82559ER chips.
1105 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1106 write routine for first time initialisation.
1109 Support for Digital 2114x chips.
1110 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1111 modem chip initialisation (KS8761/QS6611).
1114 Support for National dp83815 chips.
1117 Support for National dp8382[01] gigabit chips.
1119 - NETWORK Support (other):
1121 CONFIG_DRIVER_AT91EMAC
1122 Support for AT91RM9200 EMAC.
1125 Define this to use reduced MII inteface
1127 CONFIG_DRIVER_AT91EMAC_QUIET
1128 If this defined, the driver is quiet.
1129 The driver doen't show link status messages.
1131 CONFIG_CALXEDA_XGMAC
1132 Support for the Calxeda XGMAC device
1135 Support for SMSC's LAN91C96 chips.
1137 CONFIG_LAN91C96_BASE
1138 Define this to hold the physical address
1139 of the LAN91C96's I/O space
1141 CONFIG_LAN91C96_USE_32_BIT
1142 Define this to enable 32 bit addressing
1145 Support for SMSC's LAN91C111 chip
1147 CONFIG_SMC91111_BASE
1148 Define this to hold the physical address
1149 of the device (I/O space)
1151 CONFIG_SMC_USE_32_BIT
1152 Define this if data bus is 32 bits
1154 CONFIG_SMC_USE_IOFUNCS
1155 Define this to use i/o functions instead of macros
1156 (some hardware wont work with macros)
1158 CONFIG_DRIVER_TI_EMAC
1159 Support for davinci emac
1161 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1162 Define this if you have more then 3 PHYs.
1165 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1167 CONFIG_FTGMAC100_EGIGA
1168 Define this to use GE link update with gigabit PHY.
1169 Define this if FTGMAC100 is connected to gigabit PHY.
1170 If your system has 10/100 PHY only, it might not occur
1171 wrong behavior. Because PHY usually return timeout or
1172 useless data when polling gigabit status and gigabit
1173 control registers. This behavior won't affect the
1174 correctnessof 10/100 link speed update.
1177 Support for SMSC's LAN911x and LAN921x chips
1180 Define this to hold the physical address
1181 of the device (I/O space)
1183 CONFIG_SMC911X_32_BIT
1184 Define this if data bus is 32 bits
1186 CONFIG_SMC911X_16_BIT
1187 Define this if data bus is 16 bits. If your processor
1188 automatically converts one 32 bit word to two 16 bit
1189 words you may also try CONFIG_SMC911X_32_BIT.
1192 Support for Renesas on-chip Ethernet controller
1194 CONFIG_SH_ETHER_USE_PORT
1195 Define the number of ports to be used
1197 CONFIG_SH_ETHER_PHY_ADDR
1198 Define the ETH PHY's address
1200 CONFIG_SH_ETHER_CACHE_WRITEBACK
1201 If this option is set, the driver enables cache flush.
1204 CONFIG_GENERIC_LPC_TPM
1205 Support for generic parallel port TPM devices. Only one device
1206 per system is supported at this time.
1208 CONFIG_TPM_TIS_BASE_ADDRESS
1209 Base address where the generic TPM device is mapped
1210 to. Contemporary x86 systems usually map it at
1214 At the moment only the UHCI host controller is
1215 supported (PIP405, MIP405, MPC5200); define
1216 CONFIG_USB_UHCI to enable it.
1217 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1218 and define CONFIG_USB_STORAGE to enable the USB
1221 Supported are USB Keyboards and USB Floppy drives
1223 MPC5200 USB requires additional defines:
1225 for 528 MHz Clock: 0x0001bbbb
1229 for differential drivers: 0x00001000
1230 for single ended drivers: 0x00005000
1231 for differential drivers on PSC3: 0x00000100
1232 for single ended drivers on PSC3: 0x00004100
1233 CONFIG_SYS_USB_EVENT_POLL
1234 May be defined to allow interrupt polling
1235 instead of using asynchronous interrupts
1237 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1238 txfilltuning field in the EHCI controller on reset.
1241 Define the below if you wish to use the USB console.
1242 Once firmware is rebuilt from a serial console issue the
1243 command "setenv stdin usbtty; setenv stdout usbtty" and
1244 attach your USB cable. The Unix command "dmesg" should print
1245 it has found a new device. The environment variable usbtty
1246 can be set to gserial or cdc_acm to enable your device to
1247 appear to a USB host as a Linux gserial device or a
1248 Common Device Class Abstract Control Model serial device.
1249 If you select usbtty = gserial you should be able to enumerate
1251 # modprobe usbserial vendor=0xVendorID product=0xProductID
1252 else if using cdc_acm, simply setting the environment
1253 variable usbtty to be cdc_acm should suffice. The following
1254 might be defined in YourBoardName.h
1257 Define this to build a UDC device
1260 Define this to have a tty type of device available to
1261 talk to the UDC device
1264 Define this to enable the high speed support for usb
1265 device and usbtty. If this feature is enabled, a routine
1266 int is_usbd_high_speed(void)
1267 also needs to be defined by the driver to dynamically poll
1268 whether the enumeration has succeded at high speed or full
1271 CONFIG_SYS_CONSOLE_IS_IN_ENV
1272 Define this if you want stdin, stdout &/or stderr to
1276 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1277 Derive USB clock from external clock "blah"
1278 - CONFIG_SYS_USB_EXTC_CLK 0x02
1280 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1281 Derive USB clock from brgclk
1282 - CONFIG_SYS_USB_BRG_CLK 0x04
1284 If you have a USB-IF assigned VendorID then you may wish to
1285 define your own vendor specific values either in BoardName.h
1286 or directly in usbd_vendor_info.h. If you don't define
1287 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1288 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1289 should pretend to be a Linux device to it's target host.
1291 CONFIG_USBD_MANUFACTURER
1292 Define this string as the name of your company for
1293 - CONFIG_USBD_MANUFACTURER "my company"
1295 CONFIG_USBD_PRODUCT_NAME
1296 Define this string as the name of your product
1297 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1299 CONFIG_USBD_VENDORID
1300 Define this as your assigned Vendor ID from the USB
1301 Implementors Forum. This *must* be a genuine Vendor ID
1302 to avoid polluting the USB namespace.
1303 - CONFIG_USBD_VENDORID 0xFFFF
1305 CONFIG_USBD_PRODUCTID
1306 Define this as the unique Product ID
1308 - CONFIG_USBD_PRODUCTID 0xFFFF
1310 - ULPI Layer Support:
1311 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1312 the generic ULPI layer. The generic layer accesses the ULPI PHY
1313 via the platform viewport, so you need both the genric layer and
1314 the viewport enabled. Currently only Chipidea/ARC based
1315 viewport is supported.
1316 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1317 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1318 If your ULPI phy needs a different reference clock than the
1319 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1320 the appropriate value in Hz.
1323 The MMC controller on the Intel PXA is supported. To
1324 enable this define CONFIG_MMC. The MMC can be
1325 accessed from the boot prompt by mapping the device
1326 to physical memory similar to flash. Command line is
1327 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1328 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1331 Support for Renesas on-chip MMCIF controller
1333 CONFIG_SH_MMCIF_ADDR
1334 Define the base address of MMCIF registers
1337 Define the clock frequency for MMCIF
1339 - Journaling Flash filesystem support:
1340 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1341 CONFIG_JFFS2_NAND_DEV
1342 Define these for a default partition on a NAND device
1344 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1345 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1346 Define these for a default partition on a NOR device
1348 CONFIG_SYS_JFFS_CUSTOM_PART
1349 Define this to create an own partition. You have to provide a
1350 function struct part_info* jffs2_part_info(int part_num)
1352 If you define only one JFFS2 partition you may also want to
1353 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1354 to disable the command chpart. This is the default when you
1355 have not defined a custom partition
1357 - FAT(File Allocation Table) filesystem write function support:
1360 Define this to enable support for saving memory data as a
1361 file in FAT formatted partition.
1363 This will also enable the command "fatwrite" enabling the
1364 user to write files to FAT.
1366 CBFS (Coreboot Filesystem) support
1369 Define this to enable support for reading from a Coreboot
1370 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1376 Define this to enable standard (PC-Style) keyboard
1380 Standard PC keyboard driver with US (is default) and
1381 GERMAN key layout (switch via environment 'keymap=de') support.
1382 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1383 for cfb_console. Supports cursor blinking.
1388 Define this to enable video support (for output to
1391 CONFIG_VIDEO_CT69000
1393 Enable Chips & Technologies 69000 Video chip
1395 CONFIG_VIDEO_SMI_LYNXEM
1396 Enable Silicon Motion SMI 712/710/810 Video chip. The
1397 video output is selected via environment 'videoout'
1398 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1401 For the CT69000 and SMI_LYNXEM drivers, videomode is
1402 selected via environment 'videomode'. Two different ways
1404 - "videomode=num" 'num' is a standard LiLo mode numbers.
1405 Following standard modes are supported (* is default):
1407 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1408 -------------+---------------------------------------------
1409 8 bits | 0x301* 0x303 0x305 0x161 0x307
1410 15 bits | 0x310 0x313 0x316 0x162 0x319
1411 16 bits | 0x311 0x314 0x317 0x163 0x31A
1412 24 bits | 0x312 0x315 0x318 ? 0x31B
1413 -------------+---------------------------------------------
1414 (i.e. setenv videomode 317; saveenv; reset;)
1416 - "videomode=bootargs" all the video parameters are parsed
1417 from the bootargs. (See drivers/video/videomodes.c)
1420 CONFIG_VIDEO_SED13806
1421 Enable Epson SED13806 driver. This driver supports 8bpp
1422 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1423 or CONFIG_VIDEO_SED13806_16BPP
1426 Enable the Freescale DIU video driver. Reference boards for
1427 SOCs that have a DIU should define this macro to enable DIU
1428 support, and should also define these other macros:
1434 CONFIG_VIDEO_SW_CURSOR
1435 CONFIG_VGA_AS_SINGLE_DEVICE
1437 CONFIG_VIDEO_BMP_LOGO
1439 The DIU driver will look for the 'video-mode' environment
1440 variable, and if defined, enable the DIU as a console during
1441 boot. See the documentation file README.video for a
1442 description of this variable.
1446 Enable the VGA video / BIOS for x86. The alternative if you
1447 are using coreboot is to use the coreboot frame buffer
1454 Define this to enable a custom keyboard support.
1455 This simply calls drv_keyboard_init() which must be
1456 defined in your board-specific files.
1457 The only board using this so far is RBC823.
1459 - LCD Support: CONFIG_LCD
1461 Define this to enable LCD support (for output to LCD
1462 display); also select one of the supported displays
1463 by defining one of these:
1467 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1469 CONFIG_NEC_NL6448AC33:
1471 NEC NL6448AC33-18. Active, color, single scan.
1473 CONFIG_NEC_NL6448BC20
1475 NEC NL6448BC20-08. 6.5", 640x480.
1476 Active, color, single scan.
1478 CONFIG_NEC_NL6448BC33_54
1480 NEC NL6448BC33-54. 10.4", 640x480.
1481 Active, color, single scan.
1485 Sharp 320x240. Active, color, single scan.
1486 It isn't 16x9, and I am not sure what it is.
1488 CONFIG_SHARP_LQ64D341
1490 Sharp LQ64D341 display, 640x480.
1491 Active, color, single scan.
1495 HLD1045 display, 640x480.
1496 Active, color, single scan.
1500 Optrex CBL50840-2 NF-FW 99 22 M5
1502 Hitachi LMG6912RPFC-00T
1506 320x240. Black & white.
1508 Normally display is black on white background; define
1509 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1511 CONFIG_LCD_ALIGNMENT
1513 Normally the LCD is page-aligned (tyically 4KB). If this is
1514 defined then the LCD will be aligned to this value instead.
1515 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1516 here, since it is cheaper to change data cache settings on
1517 a per-section basis.
1519 CONFIG_CONSOLE_SCROLL_LINES
1521 When the console need to be scrolled, this is the number of
1522 lines to scroll by. It defaults to 1. Increasing this makes
1523 the console jump but can help speed up operation when scrolling
1528 Support drawing of RLE8-compressed bitmaps on the LCD.
1532 Enables an 'i2c edid' command which can read EDID
1533 information over I2C from an attached LCD display.
1535 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1537 If this option is set, the environment is checked for
1538 a variable "splashimage". If found, the usual display
1539 of logo, copyright and system information on the LCD
1540 is suppressed and the BMP image at the address
1541 specified in "splashimage" is loaded instead. The
1542 console is redirected to the "nulldev", too. This
1543 allows for a "silent" boot where a splash screen is
1544 loaded very quickly after power-on.
1546 CONFIG_SPLASHIMAGE_GUARD
1548 If this option is set, then U-Boot will prevent the environment
1549 variable "splashimage" from being set to a problematic address
1550 (see README.displaying-bmps and README.arm-unaligned-accesses).
1551 This option is useful for targets where, due to alignment
1552 restrictions, an improperly aligned BMP image will cause a data
1553 abort. If you think you will not have problems with unaligned
1554 accesses (for example because your toolchain prevents them)
1555 there is no need to set this option.
1557 CONFIG_SPLASH_SCREEN_ALIGN
1559 If this option is set the splash image can be freely positioned
1560 on the screen. Environment variable "splashpos" specifies the
1561 position as "x,y". If a positive number is given it is used as
1562 number of pixel from left/top. If a negative number is given it
1563 is used as number of pixel from right/bottom. You can also
1564 specify 'm' for centering the image.
1567 setenv splashpos m,m
1568 => image at center of screen
1570 setenv splashpos 30,20
1571 => image at x = 30 and y = 20
1573 setenv splashpos -10,m
1574 => vertically centered image
1575 at x = dspWidth - bmpWidth - 9
1577 CONFIG_SPLASH_SCREEN_PREPARE
1579 If this option is set then the board_splash_screen_prepare()
1580 function, which must be defined in your code, is called as part
1581 of the splash screen display sequence. It gives the board an
1582 opportunity to prepare the splash image data before it is
1583 processed and sent to the frame buffer by U-Boot.
1585 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1587 If this option is set, additionally to standard BMP
1588 images, gzipped BMP images can be displayed via the
1589 splashscreen support or the bmp command.
1591 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1593 If this option is set, 8-bit RLE compressed BMP images
1594 can be displayed via the splashscreen support or the
1597 - Do compresssing for memory range:
1600 If this option is set, it would use zlib deflate method
1601 to compress the specified memory at its best effort.
1603 - Compression support:
1606 If this option is set, support for bzip2 compressed
1607 images is included. If not, only uncompressed and gzip
1608 compressed images are supported.
1610 NOTE: the bzip2 algorithm requires a lot of RAM, so
1611 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1616 If this option is set, support for lzma compressed
1619 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1620 requires an amount of dynamic memory that is given by the
1623 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1625 Where lc and lp stand for, respectively, Literal context bits
1626 and Literal pos bits.
1628 This value is upper-bounded by 14MB in the worst case. Anyway,
1629 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1630 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1631 a very small buffer.
1633 Use the lzmainfo tool to determinate the lc and lp values and
1634 then calculate the amount of needed dynamic memory (ensuring
1635 the appropriate CONFIG_SYS_MALLOC_LEN value).
1640 The address of PHY on MII bus.
1642 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1644 The clock frequency of the MII bus
1648 If this option is set, support for speed/duplex
1649 detection of gigabit PHY is included.
1651 CONFIG_PHY_RESET_DELAY
1653 Some PHY like Intel LXT971A need extra delay after
1654 reset before any MII register access is possible.
1655 For such PHY, set this option to the usec delay
1656 required. (minimum 300usec for LXT971A)
1658 CONFIG_PHY_CMD_DELAY (ppc4xx)
1660 Some PHY like Intel LXT971A need extra delay after
1661 command issued before MII status register can be read
1671 Define a default value for Ethernet address to use
1672 for the respective Ethernet interface, in case this
1673 is not determined automatically.
1678 Define a default value for the IP address to use for
1679 the default Ethernet interface, in case this is not
1680 determined through e.g. bootp.
1681 (Environment variable "ipaddr")
1683 - Server IP address:
1686 Defines a default value for the IP address of a TFTP
1687 server to contact when using the "tftboot" command.
1688 (Environment variable "serverip")
1690 CONFIG_KEEP_SERVERADDR
1692 Keeps the server's MAC address, in the env 'serveraddr'
1693 for passing to bootargs (like Linux's netconsole option)
1695 - Gateway IP address:
1698 Defines a default value for the IP address of the
1699 default router where packets to other networks are
1701 (Environment variable "gatewayip")
1706 Defines a default value for the subnet mask (or
1707 routing prefix) which is used to determine if an IP
1708 address belongs to the local subnet or needs to be
1709 forwarded through a router.
1710 (Environment variable "netmask")
1712 - Multicast TFTP Mode:
1715 Defines whether you want to support multicast TFTP as per
1716 rfc-2090; for example to work with atftp. Lets lots of targets
1717 tftp down the same boot image concurrently. Note: the Ethernet
1718 driver in use must provide a function: mcast() to join/leave a
1721 - BOOTP Recovery Mode:
1722 CONFIG_BOOTP_RANDOM_DELAY
1724 If you have many targets in a network that try to
1725 boot using BOOTP, you may want to avoid that all
1726 systems send out BOOTP requests at precisely the same
1727 moment (which would happen for instance at recovery
1728 from a power failure, when all systems will try to
1729 boot, thus flooding the BOOTP server. Defining
1730 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1731 inserted before sending out BOOTP requests. The
1732 following delays are inserted then:
1734 1st BOOTP request: delay 0 ... 1 sec
1735 2nd BOOTP request: delay 0 ... 2 sec
1736 3rd BOOTP request: delay 0 ... 4 sec
1738 BOOTP requests: delay 0 ... 8 sec
1740 - DHCP Advanced Options:
1741 You can fine tune the DHCP functionality by defining
1742 CONFIG_BOOTP_* symbols:
1744 CONFIG_BOOTP_SUBNETMASK
1745 CONFIG_BOOTP_GATEWAY
1746 CONFIG_BOOTP_HOSTNAME
1747 CONFIG_BOOTP_NISDOMAIN
1748 CONFIG_BOOTP_BOOTPATH
1749 CONFIG_BOOTP_BOOTFILESIZE
1752 CONFIG_BOOTP_SEND_HOSTNAME
1753 CONFIG_BOOTP_NTPSERVER
1754 CONFIG_BOOTP_TIMEOFFSET
1755 CONFIG_BOOTP_VENDOREX
1756 CONFIG_BOOTP_MAY_FAIL
1758 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1759 environment variable, not the BOOTP server.
1761 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1762 after the configured retry count, the call will fail
1763 instead of starting over. This can be used to fail over
1764 to Link-local IP address configuration if the DHCP server
1767 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1768 serverip from a DHCP server, it is possible that more
1769 than one DNS serverip is offered to the client.
1770 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1771 serverip will be stored in the additional environment
1772 variable "dnsip2". The first DNS serverip is always
1773 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1776 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1777 to do a dynamic update of a DNS server. To do this, they
1778 need the hostname of the DHCP requester.
1779 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1780 of the "hostname" environment variable is passed as
1781 option 12 to the DHCP server.
1783 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1785 A 32bit value in microseconds for a delay between
1786 receiving a "DHCP Offer" and sending the "DHCP Request".
1787 This fixes a problem with certain DHCP servers that don't
1788 respond 100% of the time to a "DHCP request". E.g. On an
1789 AT91RM9200 processor running at 180MHz, this delay needed
1790 to be *at least* 15,000 usec before a Windows Server 2003
1791 DHCP server would reply 100% of the time. I recommend at
1792 least 50,000 usec to be safe. The alternative is to hope
1793 that one of the retries will be successful but note that
1794 the DHCP timeout and retry process takes a longer than
1797 - Link-local IP address negotiation:
1798 Negotiate with other link-local clients on the local network
1799 for an address that doesn't require explicit configuration.
1800 This is especially useful if a DHCP server cannot be guaranteed
1801 to exist in all environments that the device must operate.
1803 See doc/README.link-local for more information.
1806 CONFIG_CDP_DEVICE_ID
1808 The device id used in CDP trigger frames.
1810 CONFIG_CDP_DEVICE_ID_PREFIX
1812 A two character string which is prefixed to the MAC address
1817 A printf format string which contains the ascii name of
1818 the port. Normally is set to "eth%d" which sets
1819 eth0 for the first Ethernet, eth1 for the second etc.
1821 CONFIG_CDP_CAPABILITIES
1823 A 32bit integer which indicates the device capabilities;
1824 0x00000010 for a normal host which does not forwards.
1828 An ascii string containing the version of the software.
1832 An ascii string containing the name of the platform.
1836 A 32bit integer sent on the trigger.
1838 CONFIG_CDP_POWER_CONSUMPTION
1840 A 16bit integer containing the power consumption of the
1841 device in .1 of milliwatts.
1843 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1845 A byte containing the id of the VLAN.
1847 - Status LED: CONFIG_STATUS_LED
1849 Several configurations allow to display the current
1850 status using a LED. For instance, the LED will blink
1851 fast while running U-Boot code, stop blinking as
1852 soon as a reply to a BOOTP request was received, and
1853 start blinking slow once the Linux kernel is running
1854 (supported by a status LED driver in the Linux
1855 kernel). Defining CONFIG_STATUS_LED enables this
1858 - CAN Support: CONFIG_CAN_DRIVER
1860 Defining CONFIG_CAN_DRIVER enables CAN driver support
1861 on those systems that support this (optional)
1862 feature, like the TQM8xxL modules.
1864 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1866 These enable I2C serial bus commands. Defining either of
1867 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1868 include the appropriate I2C driver for the selected CPU.
1870 This will allow you to use i2c commands at the u-boot
1871 command line (as long as you set CONFIG_CMD_I2C in
1872 CONFIG_COMMANDS) and communicate with i2c based realtime
1873 clock chips. See common/cmd_i2c.c for a description of the
1874 command line interface.
1876 CONFIG_HARD_I2C selects a hardware I2C controller.
1878 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1879 bit-banging) driver instead of CPM or similar hardware
1882 There are several other quantities that must also be
1883 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1885 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1886 to be the frequency (in Hz) at which you wish your i2c bus
1887 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1888 the CPU's i2c node address).
1890 Now, the u-boot i2c code for the mpc8xx
1891 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1892 and so its address should therefore be cleared to 0 (See,
1893 eg, MPC823e User's Manual p.16-473). So, set
1894 CONFIG_SYS_I2C_SLAVE to 0.
1896 CONFIG_SYS_I2C_INIT_MPC5XXX
1898 When a board is reset during an i2c bus transfer
1899 chips might think that the current transfer is still
1900 in progress. Reset the slave devices by sending start
1901 commands until the slave device responds.
1903 That's all that's required for CONFIG_HARD_I2C.
1905 If you use the software i2c interface (CONFIG_SOFT_I2C)
1906 then the following macros need to be defined (examples are
1907 from include/configs/lwmon.h):
1911 (Optional). Any commands necessary to enable the I2C
1912 controller or configure ports.
1914 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1918 (Only for MPC8260 CPU). The I/O port to use (the code
1919 assumes both bits are on the same port). Valid values
1920 are 0..3 for ports A..D.
1924 The code necessary to make the I2C data line active
1925 (driven). If the data line is open collector, this
1928 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1932 The code necessary to make the I2C data line tri-stated
1933 (inactive). If the data line is open collector, this
1936 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1940 Code that returns TRUE if the I2C data line is high,
1943 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1947 If <bit> is TRUE, sets the I2C data line high. If it
1948 is FALSE, it clears it (low).
1950 eg: #define I2C_SDA(bit) \
1951 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1952 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1956 If <bit> is TRUE, sets the I2C clock line high. If it
1957 is FALSE, it clears it (low).
1959 eg: #define I2C_SCL(bit) \
1960 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1961 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1965 This delay is invoked four times per clock cycle so this
1966 controls the rate of data transfer. The data rate thus
1967 is 1 / (I2C_DELAY * 4). Often defined to be something
1970 #define I2C_DELAY udelay(2)
1972 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1974 If your arch supports the generic GPIO framework (asm/gpio.h),
1975 then you may alternatively define the two GPIOs that are to be
1976 used as SCL / SDA. Any of the previous I2C_xxx macros will
1977 have GPIO-based defaults assigned to them as appropriate.
1979 You should define these to the GPIO value as given directly to
1980 the generic GPIO functions.
1982 CONFIG_SYS_I2C_INIT_BOARD
1984 When a board is reset during an i2c bus transfer
1985 chips might think that the current transfer is still
1986 in progress. On some boards it is possible to access
1987 the i2c SCLK line directly, either by using the
1988 processor pin as a GPIO or by having a second pin
1989 connected to the bus. If this option is defined a
1990 custom i2c_init_board() routine in boards/xxx/board.c
1991 is run early in the boot sequence.
1993 CONFIG_SYS_I2C_BOARD_LATE_INIT
1995 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1996 defined a custom i2c_board_late_init() routine in
1997 boards/xxx/board.c is run AFTER the operations in i2c_init()
1998 is completed. This callpoint can be used to unreset i2c bus
1999 using CPU i2c controller register accesses for CPUs whose i2c
2000 controller provide such a method. It is called at the end of
2001 i2c_init() to allow i2c_init operations to setup the i2c bus
2002 controller on the CPU (e.g. setting bus speed & slave address).
2004 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2006 This option enables configuration of bi_iic_fast[] flags
2007 in u-boot bd_info structure based on u-boot environment
2008 variable "i2cfast". (see also i2cfast)
2010 CONFIG_I2C_MULTI_BUS
2012 This option allows the use of multiple I2C buses, each of which
2013 must have a controller. At any point in time, only one bus is
2014 active. To switch to a different bus, use the 'i2c dev' command.
2015 Note that bus numbering is zero-based.
2017 CONFIG_SYS_I2C_NOPROBES
2019 This option specifies a list of I2C devices that will be skipped
2020 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2021 is set, specify a list of bus-device pairs. Otherwise, specify
2022 a 1D array of device addresses
2025 #undef CONFIG_I2C_MULTI_BUS
2026 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2028 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2030 #define CONFIG_I2C_MULTI_BUS
2031 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2033 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2035 CONFIG_SYS_SPD_BUS_NUM
2037 If defined, then this indicates the I2C bus number for DDR SPD.
2038 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2040 CONFIG_SYS_RTC_BUS_NUM
2042 If defined, then this indicates the I2C bus number for the RTC.
2043 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2045 CONFIG_SYS_DTT_BUS_NUM
2047 If defined, then this indicates the I2C bus number for the DTT.
2048 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2050 CONFIG_SYS_I2C_DTT_ADDR:
2052 If defined, specifies the I2C address of the DTT device.
2053 If not defined, then U-Boot uses predefined value for
2054 specified DTT device.
2058 Define this option if you want to use Freescale's I2C driver in
2059 drivers/i2c/fsl_i2c.c.
2063 Define this option if you have I2C devices reached over 1 .. n
2064 I2C Muxes like the pca9544a. This option addes a new I2C
2065 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2066 new I2C Bus to the existing I2C Busses. If you select the
2067 new Bus with "i2c dev", u-bbot sends first the commandos for
2068 the muxes to activate this new "bus".
2070 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2074 Adding a new I2C Bus reached over 2 pca9544a muxes
2075 The First mux with address 70 and channel 6
2076 The Second mux with address 71 and channel 4
2078 => i2c bus pca9544a:70:6:pca9544a:71:4
2080 Use the "i2c bus" command without parameter, to get a list
2081 of I2C Busses with muxes:
2084 Busses reached over muxes:
2086 reached over Mux(es):
2089 reached over Mux(es):
2094 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2095 u-boot first sends the command to the mux@70 to enable
2096 channel 6, and then the command to the mux@71 to enable
2099 After that, you can use the "normal" i2c commands as
2100 usual to communicate with your I2C devices behind
2103 This option is actually implemented for the bitbanging
2104 algorithm in common/soft_i2c.c and for the Hardware I2C
2105 Bus on the MPC8260. But it should be not so difficult
2106 to add this option to other architectures.
2108 CONFIG_SOFT_I2C_READ_REPEATED_START
2110 defining this will force the i2c_read() function in
2111 the soft_i2c driver to perform an I2C repeated start
2112 between writing the address pointer and reading the
2113 data. If this define is omitted the default behaviour
2114 of doing a stop-start sequence will be used. Most I2C
2115 devices can use either method, but some require one or
2118 - SPI Support: CONFIG_SPI
2120 Enables SPI driver (so far only tested with
2121 SPI EEPROM, also an instance works with Crystal A/D and
2122 D/As on the SACSng board)
2126 Enables the driver for SPI controller on SuperH. Currently
2127 only SH7757 is supported.
2131 Enables extended (16-bit) SPI EEPROM addressing.
2132 (symmetrical to CONFIG_I2C_X)
2136 Enables a software (bit-bang) SPI driver rather than
2137 using hardware support. This is a general purpose
2138 driver that only requires three general I/O port pins
2139 (two outputs, one input) to function. If this is
2140 defined, the board configuration must define several
2141 SPI configuration items (port pins to use, etc). For
2142 an example, see include/configs/sacsng.h.
2146 Enables a hardware SPI driver for general-purpose reads
2147 and writes. As with CONFIG_SOFT_SPI, the board configuration
2148 must define a list of chip-select function pointers.
2149 Currently supported on some MPC8xxx processors. For an
2150 example, see include/configs/mpc8349emds.h.
2154 Enables the driver for the SPI controllers on i.MX and MXC
2155 SoCs. Currently i.MX31/35/51 are supported.
2157 - FPGA Support: CONFIG_FPGA
2159 Enables FPGA subsystem.
2161 CONFIG_FPGA_<vendor>
2163 Enables support for specific chip vendors.
2166 CONFIG_FPGA_<family>
2168 Enables support for FPGA family.
2169 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2173 Specify the number of FPGA devices to support.
2175 CONFIG_SYS_FPGA_PROG_FEEDBACK
2177 Enable printing of hash marks during FPGA configuration.
2179 CONFIG_SYS_FPGA_CHECK_BUSY
2181 Enable checks on FPGA configuration interface busy
2182 status by the configuration function. This option
2183 will require a board or device specific function to
2188 If defined, a function that provides delays in the FPGA
2189 configuration driver.
2191 CONFIG_SYS_FPGA_CHECK_CTRLC
2192 Allow Control-C to interrupt FPGA configuration
2194 CONFIG_SYS_FPGA_CHECK_ERROR
2196 Check for configuration errors during FPGA bitfile
2197 loading. For example, abort during Virtex II
2198 configuration if the INIT_B line goes low (which
2199 indicated a CRC error).
2201 CONFIG_SYS_FPGA_WAIT_INIT
2203 Maximum time to wait for the INIT_B line to deassert
2204 after PROB_B has been deasserted during a Virtex II
2205 FPGA configuration sequence. The default time is 500
2208 CONFIG_SYS_FPGA_WAIT_BUSY
2210 Maximum time to wait for BUSY to deassert during
2211 Virtex II FPGA configuration. The default is 5 ms.
2213 CONFIG_SYS_FPGA_WAIT_CONFIG
2215 Time to wait after FPGA configuration. The default is
2218 - Configuration Management:
2221 If defined, this string will be added to the U-Boot
2222 version information (U_BOOT_VERSION)
2224 - Vendor Parameter Protection:
2226 U-Boot considers the values of the environment
2227 variables "serial#" (Board Serial Number) and
2228 "ethaddr" (Ethernet Address) to be parameters that
2229 are set once by the board vendor / manufacturer, and
2230 protects these variables from casual modification by
2231 the user. Once set, these variables are read-only,
2232 and write or delete attempts are rejected. You can
2233 change this behaviour:
2235 If CONFIG_ENV_OVERWRITE is #defined in your config
2236 file, the write protection for vendor parameters is
2237 completely disabled. Anybody can change or delete
2240 Alternatively, if you #define _both_ CONFIG_ETHADDR
2241 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2242 Ethernet address is installed in the environment,
2243 which can be changed exactly ONCE by the user. [The
2244 serial# is unaffected by this, i. e. it remains
2247 The same can be accomplished in a more flexible way
2248 for any variable by configuring the type of access
2249 to allow for those variables in the ".flags" variable
2250 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2255 Define this variable to enable the reservation of
2256 "protected RAM", i. e. RAM which is not overwritten
2257 by U-Boot. Define CONFIG_PRAM to hold the number of
2258 kB you want to reserve for pRAM. You can overwrite
2259 this default value by defining an environment
2260 variable "pram" to the number of kB you want to
2261 reserve. Note that the board info structure will
2262 still show the full amount of RAM. If pRAM is
2263 reserved, a new environment variable "mem" will
2264 automatically be defined to hold the amount of
2265 remaining RAM in a form that can be passed as boot
2266 argument to Linux, for instance like that:
2268 setenv bootargs ... mem=\${mem}
2271 This way you can tell Linux not to use this memory,
2272 either, which results in a memory region that will
2273 not be affected by reboots.
2275 *WARNING* If your board configuration uses automatic
2276 detection of the RAM size, you must make sure that
2277 this memory test is non-destructive. So far, the
2278 following board configurations are known to be
2281 IVMS8, IVML24, SPD8xx, TQM8xxL,
2282 HERMES, IP860, RPXlite, LWMON,
2285 - Access to physical memory region (> 4GB)
2286 Some basic support is provided for operations on memory not
2287 normally accessible to U-Boot - e.g. some architectures
2288 support access to more than 4GB of memory on 32-bit
2289 machines using physical address extension or similar.
2290 Define CONFIG_PHYSMEM to access this basic support, which
2291 currently only supports clearing the memory.
2296 Define this variable to stop the system in case of a
2297 fatal error, so that you have to reset it manually.
2298 This is probably NOT a good idea for an embedded
2299 system where you want the system to reboot
2300 automatically as fast as possible, but it may be
2301 useful during development since you can try to debug
2302 the conditions that lead to the situation.
2304 CONFIG_NET_RETRY_COUNT
2306 This variable defines the number of retries for
2307 network operations like ARP, RARP, TFTP, or BOOTP
2308 before giving up the operation. If not defined, a
2309 default value of 5 is used.
2313 Timeout waiting for an ARP reply in milliseconds.
2317 Timeout in milliseconds used in NFS protocol.
2318 If you encounter "ERROR: Cannot umount" in nfs command,
2319 try longer timeout such as
2320 #define CONFIG_NFS_TIMEOUT 10000UL
2322 - Command Interpreter:
2323 CONFIG_AUTO_COMPLETE
2325 Enable auto completion of commands using TAB.
2327 Note that this feature has NOT been implemented yet
2328 for the "hush" shell.
2331 CONFIG_SYS_HUSH_PARSER
2333 Define this variable to enable the "hush" shell (from
2334 Busybox) as command line interpreter, thus enabling
2335 powerful command line syntax like
2336 if...then...else...fi conditionals or `&&' and '||'
2337 constructs ("shell scripts").
2339 If undefined, you get the old, much simpler behaviour
2340 with a somewhat smaller memory footprint.
2343 CONFIG_SYS_PROMPT_HUSH_PS2
2345 This defines the secondary prompt string, which is
2346 printed when the command interpreter needs more input
2347 to complete a command. Usually "> ".
2351 In the current implementation, the local variables
2352 space and global environment variables space are
2353 separated. Local variables are those you define by
2354 simply typing `name=value'. To access a local
2355 variable later on, you have write `$name' or
2356 `${name}'; to execute the contents of a variable
2357 directly type `$name' at the command prompt.
2359 Global environment variables are those you use
2360 setenv/printenv to work with. To run a command stored
2361 in such a variable, you need to use the run command,
2362 and you must not use the '$' sign to access them.
2364 To store commands and special characters in a
2365 variable, please use double quotation marks
2366 surrounding the whole text of the variable, instead
2367 of the backslashes before semicolons and special
2370 - Commandline Editing and History:
2371 CONFIG_CMDLINE_EDITING
2373 Enable editing and History functions for interactive
2374 commandline input operations
2376 - Default Environment:
2377 CONFIG_EXTRA_ENV_SETTINGS
2379 Define this to contain any number of null terminated
2380 strings (variable = value pairs) that will be part of
2381 the default environment compiled into the boot image.
2383 For example, place something like this in your
2384 board's config file:
2386 #define CONFIG_EXTRA_ENV_SETTINGS \
2390 Warning: This method is based on knowledge about the
2391 internal format how the environment is stored by the
2392 U-Boot code. This is NOT an official, exported
2393 interface! Although it is unlikely that this format
2394 will change soon, there is no guarantee either.
2395 You better know what you are doing here.
2397 Note: overly (ab)use of the default environment is
2398 discouraged. Make sure to check other ways to preset
2399 the environment like the "source" command or the
2402 CONFIG_ENV_VARS_UBOOT_CONFIG
2404 Define this in order to add variables describing the
2405 U-Boot build configuration to the default environment.
2406 These will be named arch, cpu, board, vendor, and soc.
2408 Enabling this option will cause the following to be defined:
2416 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2418 Define this in order to add variables describing certain
2419 run-time determined information about the hardware to the
2420 environment. These will be named board_name, board_rev.
2422 CONFIG_DELAY_ENVIRONMENT
2424 Normally the environment is loaded when the board is
2425 intialised so that it is available to U-Boot. This inhibits
2426 that so that the environment is not available until
2427 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2428 this is instead controlled by the value of
2429 /config/load-environment.
2431 - DataFlash Support:
2432 CONFIG_HAS_DATAFLASH
2434 Defining this option enables DataFlash features and
2435 allows to read/write in Dataflash via the standard
2438 - Serial Flash support
2441 Defining this option enables SPI flash commands
2442 'sf probe/read/write/erase/update'.
2444 Usage requires an initial 'probe' to define the serial
2445 flash parameters, followed by read/write/erase/update
2448 The following defaults may be provided by the platform
2449 to handle the common case when only a single serial
2450 flash is present on the system.
2452 CONFIG_SF_DEFAULT_BUS Bus identifier
2453 CONFIG_SF_DEFAULT_CS Chip-select
2454 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2455 CONFIG_SF_DEFAULT_SPEED in Hz
2459 Define this option to include a destructive SPI flash
2462 - SystemACE Support:
2465 Adding this option adds support for Xilinx SystemACE
2466 chips attached via some sort of local bus. The address
2467 of the chip must also be defined in the
2468 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2470 #define CONFIG_SYSTEMACE
2471 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2473 When SystemACE support is added, the "ace" device type
2474 becomes available to the fat commands, i.e. fatls.
2476 - TFTP Fixed UDP Port:
2479 If this is defined, the environment variable tftpsrcp
2480 is used to supply the TFTP UDP source port value.
2481 If tftpsrcp isn't defined, the normal pseudo-random port
2482 number generator is used.
2484 Also, the environment variable tftpdstp is used to supply
2485 the TFTP UDP destination port value. If tftpdstp isn't
2486 defined, the normal port 69 is used.
2488 The purpose for tftpsrcp is to allow a TFTP server to
2489 blindly start the TFTP transfer using the pre-configured
2490 target IP address and UDP port. This has the effect of
2491 "punching through" the (Windows XP) firewall, allowing
2492 the remainder of the TFTP transfer to proceed normally.
2493 A better solution is to properly configure the firewall,
2494 but sometimes that is not allowed.
2499 This enables a generic 'hash' command which can produce
2500 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2504 Enable the hash verify command (hash -v). This adds to code
2507 CONFIG_SHA1 - support SHA1 hashing
2508 CONFIG_SHA256 - support SHA256 hashing
2510 Note: There is also a sha1sum command, which should perhaps
2511 be deprecated in favour of 'hash sha1'.
2513 - Show boot progress:
2514 CONFIG_SHOW_BOOT_PROGRESS
2516 Defining this option allows to add some board-
2517 specific code (calling a user-provided function
2518 "show_boot_progress(int)") that enables you to show
2519 the system's boot progress on some display (for
2520 example, some LED's) on your board. At the moment,
2521 the following checkpoints are implemented:
2523 - Detailed boot stage timing
2525 Define this option to get detailed timing of each stage
2526 of the boot process.
2528 CONFIG_BOOTSTAGE_USER_COUNT
2529 This is the number of available user bootstage records.
2530 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2531 a new ID will be allocated from this stash. If you exceed
2532 the limit, recording will stop.
2534 CONFIG_BOOTSTAGE_REPORT
2535 Define this to print a report before boot, similar to this:
2537 Timer summary in microseconds:
2540 3,575,678 3,575,678 board_init_f start
2541 3,575,695 17 arch_cpu_init A9
2542 3,575,777 82 arch_cpu_init done
2543 3,659,598 83,821 board_init_r start
2544 3,910,375 250,777 main_loop
2545 29,916,167 26,005,792 bootm_start
2546 30,361,327 445,160 start_kernel
2548 CONFIG_CMD_BOOTSTAGE
2549 Add a 'bootstage' command which supports printing a report
2550 and un/stashing of bootstage data.
2552 CONFIG_BOOTSTAGE_FDT
2553 Stash the bootstage information in the FDT. A root 'bootstage'
2554 node is created with each bootstage id as a child. Each child
2555 has a 'name' property and either 'mark' containing the
2556 mark time in microsecond, or 'accum' containing the
2557 accumulated time for that bootstage id in microseconds.
2562 name = "board_init_f";
2571 Code in the Linux kernel can find this in /proc/devicetree.
2573 Legacy uImage format:
2576 1 common/cmd_bootm.c before attempting to boot an image
2577 -1 common/cmd_bootm.c Image header has bad magic number
2578 2 common/cmd_bootm.c Image header has correct magic number
2579 -2 common/cmd_bootm.c Image header has bad checksum
2580 3 common/cmd_bootm.c Image header has correct checksum
2581 -3 common/cmd_bootm.c Image data has bad checksum
2582 4 common/cmd_bootm.c Image data has correct checksum
2583 -4 common/cmd_bootm.c Image is for unsupported architecture
2584 5 common/cmd_bootm.c Architecture check OK
2585 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2586 6 common/cmd_bootm.c Image Type check OK
2587 -6 common/cmd_bootm.c gunzip uncompression error
2588 -7 common/cmd_bootm.c Unimplemented compression type
2589 7 common/cmd_bootm.c Uncompression OK
2590 8 common/cmd_bootm.c No uncompress/copy overwrite error
2591 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2593 9 common/image.c Start initial ramdisk verification
2594 -10 common/image.c Ramdisk header has bad magic number
2595 -11 common/image.c Ramdisk header has bad checksum
2596 10 common/image.c Ramdisk header is OK
2597 -12 common/image.c Ramdisk data has bad checksum
2598 11 common/image.c Ramdisk data has correct checksum
2599 12 common/image.c Ramdisk verification complete, start loading
2600 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2601 13 common/image.c Start multifile image verification
2602 14 common/image.c No initial ramdisk, no multifile, continue.
2604 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2606 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2607 -31 post/post.c POST test failed, detected by post_output_backlog()
2608 -32 post/post.c POST test failed, detected by post_run_single()
2610 34 common/cmd_doc.c before loading a Image from a DOC device
2611 -35 common/cmd_doc.c Bad usage of "doc" command
2612 35 common/cmd_doc.c correct usage of "doc" command
2613 -36 common/cmd_doc.c No boot device
2614 36 common/cmd_doc.c correct boot device
2615 -37 common/cmd_doc.c Unknown Chip ID on boot device
2616 37 common/cmd_doc.c correct chip ID found, device available
2617 -38 common/cmd_doc.c Read Error on boot device
2618 38 common/cmd_doc.c reading Image header from DOC device OK
2619 -39 common/cmd_doc.c Image header has bad magic number
2620 39 common/cmd_doc.c Image header has correct magic number
2621 -40 common/cmd_doc.c Error reading Image from DOC device
2622 40 common/cmd_doc.c Image header has correct magic number
2623 41 common/cmd_ide.c before loading a Image from a IDE device
2624 -42 common/cmd_ide.c Bad usage of "ide" command
2625 42 common/cmd_ide.c correct usage of "ide" command
2626 -43 common/cmd_ide.c No boot device
2627 43 common/cmd_ide.c boot device found
2628 -44 common/cmd_ide.c Device not available
2629 44 common/cmd_ide.c Device available
2630 -45 common/cmd_ide.c wrong partition selected
2631 45 common/cmd_ide.c partition selected
2632 -46 common/cmd_ide.c Unknown partition table
2633 46 common/cmd_ide.c valid partition table found
2634 -47 common/cmd_ide.c Invalid partition type
2635 47 common/cmd_ide.c correct partition type
2636 -48 common/cmd_ide.c Error reading Image Header on boot device
2637 48 common/cmd_ide.c reading Image Header from IDE device OK
2638 -49 common/cmd_ide.c Image header has bad magic number
2639 49 common/cmd_ide.c Image header has correct magic number
2640 -50 common/cmd_ide.c Image header has bad checksum
2641 50 common/cmd_ide.c Image header has correct checksum
2642 -51 common/cmd_ide.c Error reading Image from IDE device
2643 51 common/cmd_ide.c reading Image from IDE device OK
2644 52 common/cmd_nand.c before loading a Image from a NAND device
2645 -53 common/cmd_nand.c Bad usage of "nand" command
2646 53 common/cmd_nand.c correct usage of "nand" command
2647 -54 common/cmd_nand.c No boot device
2648 54 common/cmd_nand.c boot device found
2649 -55 common/cmd_nand.c Unknown Chip ID on boot device
2650 55 common/cmd_nand.c correct chip ID found, device available
2651 -56 common/cmd_nand.c Error reading Image Header on boot device
2652 56 common/cmd_nand.c reading Image Header from NAND device OK
2653 -57 common/cmd_nand.c Image header has bad magic number
2654 57 common/cmd_nand.c Image header has correct magic number
2655 -58 common/cmd_nand.c Error reading Image from NAND device
2656 58 common/cmd_nand.c reading Image from NAND device OK
2658 -60 common/env_common.c Environment has a bad CRC, using default
2660 64 net/eth.c starting with Ethernet configuration.
2661 -64 net/eth.c no Ethernet found.
2662 65 net/eth.c Ethernet found.
2664 -80 common/cmd_net.c usage wrong
2665 80 common/cmd_net.c before calling NetLoop()
2666 -81 common/cmd_net.c some error in NetLoop() occurred
2667 81 common/cmd_net.c NetLoop() back without error
2668 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2669 82 common/cmd_net.c trying automatic boot
2670 83 common/cmd_net.c running "source" command
2671 -83 common/cmd_net.c some error in automatic boot or "source" command
2672 84 common/cmd_net.c end without errors
2677 100 common/cmd_bootm.c Kernel FIT Image has correct format
2678 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2679 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2680 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2681 102 common/cmd_bootm.c Kernel unit name specified
2682 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2683 103 common/cmd_bootm.c Found configuration node
2684 104 common/cmd_bootm.c Got kernel subimage node offset
2685 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2686 105 common/cmd_bootm.c Kernel subimage hash verification OK
2687 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2688 106 common/cmd_bootm.c Architecture check OK
2689 -106 common/cmd_bootm.c Kernel subimage has wrong type
2690 107 common/cmd_bootm.c Kernel subimage type OK
2691 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2692 108 common/cmd_bootm.c Got kernel subimage data/size
2693 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2694 -109 common/cmd_bootm.c Can't get kernel subimage type
2695 -110 common/cmd_bootm.c Can't get kernel subimage comp
2696 -111 common/cmd_bootm.c Can't get kernel subimage os
2697 -112 common/cmd_bootm.c Can't get kernel subimage load address
2698 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2700 120 common/image.c Start initial ramdisk verification
2701 -120 common/image.c Ramdisk FIT image has incorrect format
2702 121 common/image.c Ramdisk FIT image has correct format
2703 122 common/image.c No ramdisk subimage unit name, using configuration
2704 -122 common/image.c Can't get configuration for ramdisk subimage
2705 123 common/image.c Ramdisk unit name specified
2706 -124 common/image.c Can't get ramdisk subimage node offset
2707 125 common/image.c Got ramdisk subimage node offset
2708 -125 common/image.c Ramdisk subimage hash verification failed
2709 126 common/image.c Ramdisk subimage hash verification OK
2710 -126 common/image.c Ramdisk subimage for unsupported architecture
2711 127 common/image.c Architecture check OK
2712 -127 common/image.c Can't get ramdisk subimage data/size
2713 128 common/image.c Got ramdisk subimage data/size
2714 129 common/image.c Can't get ramdisk load address
2715 -129 common/image.c Got ramdisk load address
2717 -130 common/cmd_doc.c Incorrect FIT image format
2718 131 common/cmd_doc.c FIT image format OK
2720 -140 common/cmd_ide.c Incorrect FIT image format
2721 141 common/cmd_ide.c FIT image format OK
2723 -150 common/cmd_nand.c Incorrect FIT image format
2724 151 common/cmd_nand.c FIT image format OK
2726 - FIT image support:
2728 Enable support for the FIT uImage format.
2730 CONFIG_FIT_BEST_MATCH
2731 When no configuration is explicitly selected, default to the
2732 one whose fdt's compatibility field best matches that of
2733 U-Boot itself. A match is considered "best" if it matches the
2734 most specific compatibility entry of U-Boot's fdt's root node.
2735 The order of entries in the configuration's fdt is ignored.
2737 - Standalone program support:
2738 CONFIG_STANDALONE_LOAD_ADDR
2740 This option defines a board specific value for the
2741 address where standalone program gets loaded, thus
2742 overwriting the architecture dependent default
2745 - Frame Buffer Address:
2748 Define CONFIG_FB_ADDR if you want to use specific
2749 address for frame buffer. This is typically the case
2750 when using a graphics controller has separate video
2751 memory. U-Boot will then place the frame buffer at
2752 the given address instead of dynamically reserving it
2753 in system RAM by calling lcd_setmem(), which grabs
2754 the memory for the frame buffer depending on the
2755 configured panel size.
2757 Please see board_init_f function.
2759 - Automatic software updates via TFTP server
2761 CONFIG_UPDATE_TFTP_CNT_MAX
2762 CONFIG_UPDATE_TFTP_MSEC_MAX
2764 These options enable and control the auto-update feature;
2765 for a more detailed description refer to doc/README.update.
2767 - MTD Support (mtdparts command, UBI support)
2770 Adds the MTD device infrastructure from the Linux kernel.
2771 Needed for mtdparts command support.
2773 CONFIG_MTD_PARTITIONS
2775 Adds the MTD partitioning infrastructure from the Linux
2776 kernel. Needed for UBI support.
2780 Enable building of SPL globally.
2783 LDSCRIPT for linking the SPL binary.
2786 Maximum binary size (text, data and rodata) of the SPL binary.
2788 CONFIG_SPL_TEXT_BASE
2789 TEXT_BASE for linking the SPL binary.
2791 CONFIG_SPL_RELOC_TEXT_BASE
2792 Address to relocate to. If unspecified, this is equal to
2793 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2795 CONFIG_SPL_BSS_START_ADDR
2796 Link address for the BSS within the SPL binary.
2798 CONFIG_SPL_BSS_MAX_SIZE
2799 Maximum binary size of the BSS section of the SPL binary.
2802 Adress of the start of the stack SPL will use
2804 CONFIG_SPL_RELOC_STACK
2805 Adress of the start of the stack SPL will use after
2806 relocation. If unspecified, this is equal to
2809 CONFIG_SYS_SPL_MALLOC_START
2810 Starting address of the malloc pool used in SPL.
2812 CONFIG_SYS_SPL_MALLOC_SIZE
2813 The size of the malloc pool used in SPL.
2815 CONFIG_SPL_FRAMEWORK
2816 Enable the SPL framework under common/. This framework
2817 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2818 NAND loading of the Linux Kernel.
2820 CONFIG_SPL_DISPLAY_PRINT
2821 For ARM, enable an optional function to print more information
2822 about the running system.
2824 CONFIG_SPL_INIT_MINIMAL
2825 Arch init code should be built for a very small image
2827 CONFIG_SPL_LIBCOMMON_SUPPORT
2828 Support for common/libcommon.o in SPL binary
2830 CONFIG_SPL_LIBDISK_SUPPORT
2831 Support for disk/libdisk.o in SPL binary
2833 CONFIG_SPL_I2C_SUPPORT
2834 Support for drivers/i2c/libi2c.o in SPL binary
2836 CONFIG_SPL_GPIO_SUPPORT
2837 Support for drivers/gpio/libgpio.o in SPL binary
2839 CONFIG_SPL_MMC_SUPPORT
2840 Support for drivers/mmc/libmmc.o in SPL binary
2842 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2843 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2844 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2845 Address, size and partition on the MMC to load U-Boot from
2846 when the MMC is being used in raw mode.
2848 CONFIG_SPL_FAT_SUPPORT
2849 Support for fs/fat/libfat.o in SPL binary
2851 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2852 Filename to read to load U-Boot when reading from FAT
2854 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2855 Set this for NAND SPL on PPC mpc83xx targets, so that
2856 start.S waits for the rest of the SPL to load before
2857 continuing (the hardware starts execution after just
2858 loading the first page rather than the full 4K).
2860 CONFIG_SPL_NAND_BASE
2861 Include nand_base.c in the SPL. Requires
2862 CONFIG_SPL_NAND_DRIVERS.
2864 CONFIG_SPL_NAND_DRIVERS
2865 SPL uses normal NAND drivers, not minimal drivers.
2868 Include standard software ECC in the SPL
2870 CONFIG_SPL_NAND_SIMPLE
2871 Support for NAND boot using simple NAND drivers that
2872 expose the cmd_ctrl() interface.
2874 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2875 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2876 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2877 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2878 CONFIG_SYS_NAND_ECCBYTES
2879 Defines the size and behavior of the NAND that SPL uses
2882 CONFIG_SYS_NAND_U_BOOT_OFFS
2883 Location in NAND to read U-Boot from
2885 CONFIG_SYS_NAND_U_BOOT_DST
2886 Location in memory to load U-Boot to
2888 CONFIG_SYS_NAND_U_BOOT_SIZE
2889 Size of image to load
2891 CONFIG_SYS_NAND_U_BOOT_START
2892 Entry point in loaded image to jump to
2894 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2895 Define this if you need to first read the OOB and then the
2896 data. This is used for example on davinci plattforms.
2898 CONFIG_SPL_OMAP3_ID_NAND
2899 Support for an OMAP3-specific set of functions to return the
2900 ID and MFR of the first attached NAND chip, if present.
2902 CONFIG_SPL_SERIAL_SUPPORT
2903 Support for drivers/serial/libserial.o in SPL binary
2905 CONFIG_SPL_SPI_FLASH_SUPPORT
2906 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2908 CONFIG_SPL_SPI_SUPPORT
2909 Support for drivers/spi/libspi.o in SPL binary
2911 CONFIG_SPL_RAM_DEVICE
2912 Support for running image already present in ram, in SPL binary
2914 CONFIG_SPL_LIBGENERIC_SUPPORT
2915 Support for lib/libgeneric.o in SPL binary
2918 Linker address to which the SPL should be padded before
2919 appending the SPL payload.
2922 Final target image containing SPL and payload. Some SPLs
2923 use an arch-specific makefile fragment instead, for
2924 example if more than one image needs to be produced.
2929 [so far only for SMDK2400 boards]
2931 - Modem support enable:
2932 CONFIG_MODEM_SUPPORT
2934 - RTS/CTS Flow control enable:
2937 - Modem debug support:
2938 CONFIG_MODEM_SUPPORT_DEBUG
2940 Enables debugging stuff (char screen[1024], dbg())
2941 for modem support. Useful only with BDI2000.
2943 - Interrupt support (PPC):
2945 There are common interrupt_init() and timer_interrupt()
2946 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2947 for CPU specific initialization. interrupt_init_cpu()
2948 should set decrementer_count to appropriate value. If
2949 CPU resets decrementer automatically after interrupt
2950 (ppc4xx) it should set decrementer_count to zero.
2951 timer_interrupt() calls timer_interrupt_cpu() for CPU
2952 specific handling. If board has watchdog / status_led
2953 / other_activity_monitor it works automatically from
2954 general timer_interrupt().
2958 In the target system modem support is enabled when a
2959 specific key (key combination) is pressed during
2960 power-on. Otherwise U-Boot will boot normally
2961 (autoboot). The key_pressed() function is called from
2962 board_init(). Currently key_pressed() is a dummy
2963 function, returning 1 and thus enabling modem
2966 If there are no modem init strings in the
2967 environment, U-Boot proceed to autoboot; the
2968 previous output (banner, info printfs) will be
2971 See also: doc/README.Modem
2973 Board initialization settings:
2974 ------------------------------
2976 During Initialization u-boot calls a number of board specific functions
2977 to allow the preparation of board specific prerequisites, e.g. pin setup
2978 before drivers are initialized. To enable these callbacks the
2979 following configuration macros have to be defined. Currently this is
2980 architecture specific, so please check arch/your_architecture/lib/board.c
2981 typically in board_init_f() and board_init_r().
2983 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2984 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2985 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2986 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2988 Configuration Settings:
2989 -----------------------
2991 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2992 undefine this when you're short of memory.
2994 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2995 width of the commands listed in the 'help' command output.
2997 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2998 prompt for user input.
3000 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3002 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3004 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3006 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3007 the application (usually a Linux kernel) when it is
3010 - CONFIG_SYS_BAUDRATE_TABLE:
3011 List of legal baudrate settings for this board.
3013 - CONFIG_SYS_CONSOLE_INFO_QUIET
3014 Suppress display of console information at boot.
3016 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3017 If the board specific function
3018 extern int overwrite_console (void);
3019 returns 1, the stdin, stderr and stdout are switched to the
3020 serial port, else the settings in the environment are used.
3022 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3023 Enable the call to overwrite_console().
3025 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3026 Enable overwrite of previous console environment settings.
3028 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3029 Begin and End addresses of the area used by the
3032 - CONFIG_SYS_ALT_MEMTEST:
3033 Enable an alternate, more extensive memory test.
3035 - CONFIG_SYS_MEMTEST_SCRATCH:
3036 Scratch address used by the alternate memory test
3037 You only need to set this if address zero isn't writeable
3039 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3040 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3041 this specified memory area will get subtracted from the top
3042 (end) of RAM and won't get "touched" at all by U-Boot. By
3043 fixing up gd->ram_size the Linux kernel should gets passed
3044 the now "corrected" memory size and won't touch it either.
3045 This should work for arch/ppc and arch/powerpc. Only Linux
3046 board ports in arch/powerpc with bootwrapper support that
3047 recalculate the memory size from the SDRAM controller setup
3048 will have to get fixed in Linux additionally.
3050 This option can be used as a workaround for the 440EPx/GRx
3051 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3054 WARNING: Please make sure that this value is a multiple of
3055 the Linux page size (normally 4k). If this is not the case,
3056 then the end address of the Linux memory will be located at a
3057 non page size aligned address and this could cause major
3060 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3061 Enable temporary baudrate change while serial download
3063 - CONFIG_SYS_SDRAM_BASE:
3064 Physical start address of SDRAM. _Must_ be 0 here.
3066 - CONFIG_SYS_MBIO_BASE:
3067 Physical start address of Motherboard I/O (if using a
3070 - CONFIG_SYS_FLASH_BASE:
3071 Physical start address of Flash memory.
3073 - CONFIG_SYS_MONITOR_BASE:
3074 Physical start address of boot monitor code (set by
3075 make config files to be same as the text base address
3076 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3077 CONFIG_SYS_FLASH_BASE when booting from flash.
3079 - CONFIG_SYS_MONITOR_LEN:
3080 Size of memory reserved for monitor code, used to
3081 determine _at_compile_time_ (!) if the environment is
3082 embedded within the U-Boot image, or in a separate
3085 - CONFIG_SYS_MALLOC_LEN:
3086 Size of DRAM reserved for malloc() use.
3088 - CONFIG_SYS_BOOTM_LEN:
3089 Normally compressed uImages are limited to an
3090 uncompressed size of 8 MBytes. If this is not enough,
3091 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3092 to adjust this setting to your needs.
3094 - CONFIG_SYS_BOOTMAPSZ:
3095 Maximum size of memory mapped by the startup code of
3096 the Linux kernel; all data that must be processed by
3097 the Linux kernel (bd_info, boot arguments, FDT blob if
3098 used) must be put below this limit, unless "bootm_low"
3099 enviroment variable is defined and non-zero. In such case
3100 all data for the Linux kernel must be between "bootm_low"
3101 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3102 variable "bootm_mapsize" will override the value of
3103 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3104 then the value in "bootm_size" will be used instead.
3106 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3107 Enable initrd_high functionality. If defined then the
3108 initrd_high feature is enabled and the bootm ramdisk subcommand
3111 - CONFIG_SYS_BOOT_GET_CMDLINE:
3112 Enables allocating and saving kernel cmdline in space between
3113 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3115 - CONFIG_SYS_BOOT_GET_KBD:
3116 Enables allocating and saving a kernel copy of the bd_info in
3117 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3119 - CONFIG_SYS_MAX_FLASH_BANKS:
3120 Max number of Flash memory banks
3122 - CONFIG_SYS_MAX_FLASH_SECT:
3123 Max number of sectors on a Flash chip
3125 - CONFIG_SYS_FLASH_ERASE_TOUT:
3126 Timeout for Flash erase operations (in ms)
3128 - CONFIG_SYS_FLASH_WRITE_TOUT:
3129 Timeout for Flash write operations (in ms)
3131 - CONFIG_SYS_FLASH_LOCK_TOUT
3132 Timeout for Flash set sector lock bit operation (in ms)
3134 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3135 Timeout for Flash clear lock bits operation (in ms)
3137 - CONFIG_SYS_FLASH_PROTECTION
3138 If defined, hardware flash sectors protection is used
3139 instead of U-Boot software protection.
3141 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3143 Enable TFTP transfers directly to flash memory;
3144 without this option such a download has to be
3145 performed in two steps: (1) download to RAM, and (2)
3146 copy from RAM to flash.
3148 The two-step approach is usually more reliable, since
3149 you can check if the download worked before you erase
3150 the flash, but in some situations (when system RAM is
3151 too limited to allow for a temporary copy of the
3152 downloaded image) this option may be very useful.
3154 - CONFIG_SYS_FLASH_CFI:
3155 Define if the flash driver uses extra elements in the
3156 common flash structure for storing flash geometry.
3158 - CONFIG_FLASH_CFI_DRIVER
3159 This option also enables the building of the cfi_flash driver
3160 in the drivers directory
3162 - CONFIG_FLASH_CFI_MTD
3163 This option enables the building of the cfi_mtd driver
3164 in the drivers directory. The driver exports CFI flash
3167 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3168 Use buffered writes to flash.
3170 - CONFIG_FLASH_SPANSION_S29WS_N
3171 s29ws-n MirrorBit flash has non-standard addresses for buffered
3174 - CONFIG_SYS_FLASH_QUIET_TEST
3175 If this option is defined, the common CFI flash doesn't
3176 print it's warning upon not recognized FLASH banks. This
3177 is useful, if some of the configured banks are only
3178 optionally available.
3180 - CONFIG_FLASH_SHOW_PROGRESS
3181 If defined (must be an integer), print out countdown
3182 digits and dots. Recommended value: 45 (9..1) for 80
3183 column displays, 15 (3..1) for 40 column displays.
3185 - CONFIG_SYS_RX_ETH_BUFFER:
3186 Defines the number of Ethernet receive buffers. On some
3187 Ethernet controllers it is recommended to set this value
3188 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3189 buffers can be full shortly after enabling the interface
3190 on high Ethernet traffic.
3191 Defaults to 4 if not defined.
3193 - CONFIG_ENV_MAX_ENTRIES
3195 Maximum number of entries in the hash table that is used
3196 internally to store the environment settings. The default
3197 setting is supposed to be generous and should work in most
3198 cases. This setting can be used to tune behaviour; see
3199 lib/hashtable.c for details.
3201 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3202 - CONFIG_ENV_FLAGS_LIST_STATIC
3203 Enable validation of the values given to enviroment variables when
3204 calling env set. Variables can be restricted to only decimal,
3205 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3206 the variables can also be restricted to IP address or MAC address.
3208 The format of the list is:
3209 type_attribute = [s|d|x|b|i|m]
3210 access_atribute = [a|r|o|c]
3211 attributes = type_attribute[access_atribute]
3212 entry = variable_name[:attributes]
3215 The type attributes are:
3216 s - String (default)
3219 b - Boolean ([1yYtT|0nNfF])
3223 The access attributes are:
3229 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3230 Define this to a list (string) to define the ".flags"
3231 envirnoment variable in the default or embedded environment.
3233 - CONFIG_ENV_FLAGS_LIST_STATIC
3234 Define this to a list (string) to define validation that
3235 should be done if an entry is not found in the ".flags"
3236 environment variable. To override a setting in the static
3237 list, simply add an entry for the same variable name to the
3240 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3241 If defined, don't allow the -f switch to env set override variable
3244 - CONFIG_SYS_GENERIC_BOARD
3245 This selects the architecture-generic board system instead of the
3246 architecture-specific board files. It is intended to move boards
3247 to this new framework over time. Defining this will disable the
3248 arch/foo/lib/board.c file and use common/board_f.c and
3249 common/board_r.c instead. To use this option your architecture
3250 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3251 its config.mk file). If you find problems enabling this option on
3252 your board please report the problem and send patches!
3254 - CONFIG_SYS_SYM_OFFSETS
3255 This is set by architectures that use offsets for link symbols
3256 instead of absolute values. So bss_start is obtained using an
3257 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3258 directly. You should not need to touch this setting.
3261 The following definitions that deal with the placement and management
3262 of environment data (variable area); in general, we support the
3263 following configurations:
3265 - CONFIG_BUILD_ENVCRC:
3267 Builds up envcrc with the target environment so that external utils
3268 may easily extract it and embed it in final U-Boot images.
3270 - CONFIG_ENV_IS_IN_FLASH:
3272 Define this if the environment is in flash memory.
3274 a) The environment occupies one whole flash sector, which is
3275 "embedded" in the text segment with the U-Boot code. This
3276 happens usually with "bottom boot sector" or "top boot
3277 sector" type flash chips, which have several smaller
3278 sectors at the start or the end. For instance, such a
3279 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3280 such a case you would place the environment in one of the
3281 4 kB sectors - with U-Boot code before and after it. With
3282 "top boot sector" type flash chips, you would put the
3283 environment in one of the last sectors, leaving a gap
3284 between U-Boot and the environment.
3286 - CONFIG_ENV_OFFSET:
3288 Offset of environment data (variable area) to the
3289 beginning of flash memory; for instance, with bottom boot
3290 type flash chips the second sector can be used: the offset
3291 for this sector is given here.
3293 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3297 This is just another way to specify the start address of
3298 the flash sector containing the environment (instead of
3301 - CONFIG_ENV_SECT_SIZE:
3303 Size of the sector containing the environment.
3306 b) Sometimes flash chips have few, equal sized, BIG sectors.
3307 In such a case you don't want to spend a whole sector for
3312 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3313 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3314 of this flash sector for the environment. This saves
3315 memory for the RAM copy of the environment.
3317 It may also save flash memory if you decide to use this
3318 when your environment is "embedded" within U-Boot code,
3319 since then the remainder of the flash sector could be used
3320 for U-Boot code. It should be pointed out that this is
3321 STRONGLY DISCOURAGED from a robustness point of view:
3322 updating the environment in flash makes it always
3323 necessary to erase the WHOLE sector. If something goes
3324 wrong before the contents has been restored from a copy in
3325 RAM, your target system will be dead.
3327 - CONFIG_ENV_ADDR_REDUND
3328 CONFIG_ENV_SIZE_REDUND
3330 These settings describe a second storage area used to hold
3331 a redundant copy of the environment data, so that there is
3332 a valid backup copy in case there is a power failure during
3333 a "saveenv" operation.
3335 BE CAREFUL! Any changes to the flash layout, and some changes to the
3336 source code will make it necessary to adapt <board>/u-boot.lds*
3340 - CONFIG_ENV_IS_IN_NVRAM:
3342 Define this if you have some non-volatile memory device
3343 (NVRAM, battery buffered SRAM) which you want to use for the
3349 These two #defines are used to determine the memory area you
3350 want to use for environment. It is assumed that this memory
3351 can just be read and written to, without any special
3354 BE CAREFUL! The first access to the environment happens quite early
3355 in U-Boot initalization (when we try to get the setting of for the
3356 console baudrate). You *MUST* have mapped your NVRAM area then, or
3359 Please note that even with NVRAM we still use a copy of the
3360 environment in RAM: we could work on NVRAM directly, but we want to
3361 keep settings there always unmodified except somebody uses "saveenv"
3362 to save the current settings.
3365 - CONFIG_ENV_IS_IN_EEPROM:
3367 Use this if you have an EEPROM or similar serial access
3368 device and a driver for it.
3370 - CONFIG_ENV_OFFSET:
3373 These two #defines specify the offset and size of the
3374 environment area within the total memory of your EEPROM.
3376 - CONFIG_SYS_I2C_EEPROM_ADDR:
3377 If defined, specified the chip address of the EEPROM device.
3378 The default address is zero.
3380 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3381 If defined, the number of bits used to address bytes in a
3382 single page in the EEPROM device. A 64 byte page, for example
3383 would require six bits.
3385 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3386 If defined, the number of milliseconds to delay between
3387 page writes. The default is zero milliseconds.
3389 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3390 The length in bytes of the EEPROM memory array address. Note
3391 that this is NOT the chip address length!
3393 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3394 EEPROM chips that implement "address overflow" are ones
3395 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3396 address and the extra bits end up in the "chip address" bit
3397 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3400 Note that we consider the length of the address field to
3401 still be one byte because the extra address bits are hidden
3402 in the chip address.
3404 - CONFIG_SYS_EEPROM_SIZE:
3405 The size in bytes of the EEPROM device.
3407 - CONFIG_ENV_EEPROM_IS_ON_I2C
3408 define this, if you have I2C and SPI activated, and your
3409 EEPROM, which holds the environment, is on the I2C bus.
3411 - CONFIG_I2C_ENV_EEPROM_BUS
3412 if you have an Environment on an EEPROM reached over
3413 I2C muxes, you can define here, how to reach this
3414 EEPROM. For example:
3416 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3418 EEPROM which holds the environment, is reached over
3419 a pca9547 i2c mux with address 0x70, channel 3.
3421 - CONFIG_ENV_IS_IN_DATAFLASH:
3423 Define this if you have a DataFlash memory device which you
3424 want to use for the environment.
3426 - CONFIG_ENV_OFFSET:
3430 These three #defines specify the offset and size of the
3431 environment area within the total memory of your DataFlash placed
3432 at the specified address.
3434 - CONFIG_ENV_IS_IN_REMOTE:
3436 Define this if you have a remote memory space which you
3437 want to use for the local device's environment.
3442 These two #defines specify the address and size of the
3443 environment area within the remote memory space. The
3444 local device can get the environment from remote memory
3445 space by SRIO or PCIE links.
3447 BE CAREFUL! For some special cases, the local device can not use
3448 "saveenv" command. For example, the local device will get the
3449 environment stored in a remote NOR flash by SRIO or PCIE link,
3450 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3452 - CONFIG_ENV_IS_IN_NAND:
3454 Define this if you have a NAND device which you want to use
3455 for the environment.
3457 - CONFIG_ENV_OFFSET:
3460 These two #defines specify the offset and size of the environment
3461 area within the first NAND device. CONFIG_ENV_OFFSET must be
3462 aligned to an erase block boundary.
3464 - CONFIG_ENV_OFFSET_REDUND (optional):
3466 This setting describes a second storage area of CONFIG_ENV_SIZE
3467 size used to hold a redundant copy of the environment data, so
3468 that there is a valid backup copy in case there is a power failure
3469 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3470 aligned to an erase block boundary.
3472 - CONFIG_ENV_RANGE (optional):
3474 Specifies the length of the region in which the environment
3475 can be written. This should be a multiple of the NAND device's
3476 block size. Specifying a range with more erase blocks than
3477 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3478 the range to be avoided.
3480 - CONFIG_ENV_OFFSET_OOB (optional):
3482 Enables support for dynamically retrieving the offset of the
3483 environment from block zero's out-of-band data. The
3484 "nand env.oob" command can be used to record this offset.
3485 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3486 using CONFIG_ENV_OFFSET_OOB.
3488 - CONFIG_NAND_ENV_DST
3490 Defines address in RAM to which the nand_spl code should copy the
3491 environment. If redundant environment is used, it will be copied to
3492 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3494 - CONFIG_SYS_SPI_INIT_OFFSET
3496 Defines offset to the initial SPI buffer area in DPRAM. The
3497 area is used at an early stage (ROM part) if the environment
3498 is configured to reside in the SPI EEPROM: We need a 520 byte
3499 scratch DPRAM area. It is used between the two initialization
3500 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3501 to be a good choice since it makes it far enough from the
3502 start of the data area as well as from the stack pointer.
3504 Please note that the environment is read-only until the monitor
3505 has been relocated to RAM and a RAM copy of the environment has been
3506 created; also, when using EEPROM you will have to use getenv_f()
3507 until then to read environment variables.
3509 The environment is protected by a CRC32 checksum. Before the monitor
3510 is relocated into RAM, as a result of a bad CRC you will be working
3511 with the compiled-in default environment - *silently*!!! [This is
3512 necessary, because the first environment variable we need is the
3513 "baudrate" setting for the console - if we have a bad CRC, we don't
3514 have any device yet where we could complain.]
3516 Note: once the monitor has been relocated, then it will complain if
3517 the default environment is used; a new CRC is computed as soon as you
3518 use the "saveenv" command to store a valid environment.
3520 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3521 Echo the inverted Ethernet link state to the fault LED.
3523 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3524 also needs to be defined.
3526 - CONFIG_SYS_FAULT_MII_ADDR:
3527 MII address of the PHY to check for the Ethernet link state.
3529 - CONFIG_NS16550_MIN_FUNCTIONS:
3530 Define this if you desire to only have use of the NS16550_init
3531 and NS16550_putc functions for the serial driver located at
3532 drivers/serial/ns16550.c. This option is useful for saving
3533 space for already greatly restricted images, including but not
3534 limited to NAND_SPL configurations.
3536 - CONFIG_DISPLAY_BOARDINFO
3537 Display information about the board that U-Boot is running on
3538 when U-Boot starts up. The board function checkboard() is called
3541 - CONFIG_DISPLAY_BOARDINFO_LATE
3542 Similar to the previous option, but display this information
3543 later, once stdio is running and output goes to the LCD, if
3546 Low Level (hardware related) configuration options:
3547 ---------------------------------------------------
3549 - CONFIG_SYS_CACHELINE_SIZE:
3550 Cache Line Size of the CPU.
3552 - CONFIG_SYS_DEFAULT_IMMR:
3553 Default address of the IMMR after system reset.
3555 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3556 and RPXsuper) to be able to adjust the position of
3557 the IMMR register after a reset.
3559 - CONFIG_SYS_CCSRBAR_DEFAULT:
3560 Default (power-on reset) physical address of CCSR on Freescale
3563 - CONFIG_SYS_CCSRBAR:
3564 Virtual address of CCSR. On a 32-bit build, this is typically
3565 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3567 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3568 for cross-platform code that uses that macro instead.
3570 - CONFIG_SYS_CCSRBAR_PHYS:
3571 Physical address of CCSR. CCSR can be relocated to a new
3572 physical address, if desired. In this case, this macro should
3573 be set to that address. Otherwise, it should be set to the
3574 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3575 is typically relocated on 36-bit builds. It is recommended
3576 that this macro be defined via the _HIGH and _LOW macros:
3578 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3579 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3581 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3582 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3583 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3584 used in assembly code, so it must not contain typecasts or
3585 integer size suffixes (e.g. "ULL").
3587 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3588 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3589 used in assembly code, so it must not contain typecasts or
3590 integer size suffixes (e.g. "ULL").
3592 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3593 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3594 forced to a value that ensures that CCSR is not relocated.
3596 - Floppy Disk Support:
3597 CONFIG_SYS_FDC_DRIVE_NUMBER
3599 the default drive number (default value 0)
3601 CONFIG_SYS_ISA_IO_STRIDE
3603 defines the spacing between FDC chipset registers
3606 CONFIG_SYS_ISA_IO_OFFSET
3608 defines the offset of register from address. It
3609 depends on which part of the data bus is connected to
3610 the FDC chipset. (default value 0)
3612 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3613 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3616 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3617 fdc_hw_init() is called at the beginning of the FDC
3618 setup. fdc_hw_init() must be provided by the board
3619 source code. It is used to make hardware dependant
3623 Most IDE controllers were designed to be connected with PCI
3624 interface. Only few of them were designed for AHB interface.
3625 When software is doing ATA command and data transfer to
3626 IDE devices through IDE-AHB controller, some additional
3627 registers accessing to these kind of IDE-AHB controller
3630 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3631 DO NOT CHANGE unless you know exactly what you're
3632 doing! (11-4) [MPC8xx/82xx systems only]
3634 - CONFIG_SYS_INIT_RAM_ADDR:
3636 Start address of memory area that can be used for
3637 initial data and stack; please note that this must be
3638 writable memory that is working WITHOUT special
3639 initialization, i. e. you CANNOT use normal RAM which
3640 will become available only after programming the
3641 memory controller and running certain initialization
3644 U-Boot uses the following memory types:
3645 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3646 - MPC824X: data cache
3647 - PPC4xx: data cache
3649 - CONFIG_SYS_GBL_DATA_OFFSET:
3651 Offset of the initial data structure in the memory
3652 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3653 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3654 data is located at the end of the available space
3655 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3656 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3657 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3658 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3661 On the MPC824X (or other systems that use the data
3662 cache for initial memory) the address chosen for
3663 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3664 point to an otherwise UNUSED address space between
3665 the top of RAM and the start of the PCI space.
3667 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3669 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3671 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3673 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3675 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3677 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3679 - CONFIG_SYS_OR_TIMING_SDRAM:
3682 - CONFIG_SYS_MAMR_PTA:
3683 periodic timer for refresh
3685 - CONFIG_SYS_DER: Debug Event Register (37-47)
3687 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3688 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3689 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3690 CONFIG_SYS_BR1_PRELIM:
3691 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3693 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3694 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3695 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3696 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3698 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3699 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3700 Machine Mode Register and Memory Periodic Timer
3701 Prescaler definitions (SDRAM timing)
3703 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3704 enable I2C microcode relocation patch (MPC8xx);
3705 define relocation offset in DPRAM [DSP2]
3707 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3708 enable SMC microcode relocation patch (MPC8xx);
3709 define relocation offset in DPRAM [SMC1]
3711 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3712 enable SPI microcode relocation patch (MPC8xx);
3713 define relocation offset in DPRAM [SCC4]
3715 - CONFIG_SYS_USE_OSCCLK:
3716 Use OSCM clock mode on MBX8xx board. Be careful,
3717 wrong setting might damage your board. Read
3718 doc/README.MBX before setting this variable!
3720 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3721 Offset of the bootmode word in DPRAM used by post
3722 (Power On Self Tests). This definition overrides
3723 #define'd default value in commproc.h resp.
3726 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3727 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3728 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3729 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3730 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3731 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3732 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3733 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3734 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3736 - CONFIG_PCI_DISABLE_PCIE:
3737 Disable PCI-Express on systems where it is supported but not
3740 - CONFIG_PCI_ENUM_ONLY
3741 Only scan through and get the devices on the busses.
3742 Don't do any setup work, presumably because someone or
3743 something has already done it, and we don't need to do it
3744 a second time. Useful for platforms that are pre-booted
3745 by coreboot or similar.
3748 Chip has SRIO or not
3751 Board has SRIO 1 port available
3754 Board has SRIO 2 port available
3756 - CONFIG_SYS_SRIOn_MEM_VIRT:
3757 Virtual Address of SRIO port 'n' memory region
3759 - CONFIG_SYS_SRIOn_MEM_PHYS:
3760 Physical Address of SRIO port 'n' memory region
3762 - CONFIG_SYS_SRIOn_MEM_SIZE:
3763 Size of SRIO port 'n' memory region
3765 - CONFIG_SYS_NDFC_16
3766 Defined to tell the NDFC that the NAND chip is using a
3769 - CONFIG_SYS_NDFC_EBC0_CFG
3770 Sets the EBC0_CFG register for the NDFC. If not defined
3771 a default value will be used.
3774 Get DDR timing information from an I2C EEPROM. Common
3775 with pluggable memory modules such as SODIMMs
3778 I2C address of the SPD EEPROM
3780 - CONFIG_SYS_SPD_BUS_NUM
3781 If SPD EEPROM is on an I2C bus other than the first
3782 one, specify here. Note that the value must resolve
3783 to something your driver can deal with.
3785 - CONFIG_SYS_DDR_RAW_TIMING
3786 Get DDR timing information from other than SPD. Common with
3787 soldered DDR chips onboard without SPD. DDR raw timing
3788 parameters are extracted from datasheet and hard-coded into
3789 header files or board specific files.
3791 - CONFIG_FSL_DDR_INTERACTIVE
3792 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3794 - CONFIG_SYS_83XX_DDR_USES_CS0
3795 Only for 83xx systems. If specified, then DDR should
3796 be configured using CS0 and CS1 instead of CS2 and CS3.
3798 - CONFIG_ETHER_ON_FEC[12]
3799 Define to enable FEC[12] on a 8xx series processor.
3801 - CONFIG_FEC[12]_PHY
3802 Define to the hardcoded PHY address which corresponds
3803 to the given FEC; i. e.
3804 #define CONFIG_FEC1_PHY 4
3805 means that the PHY with address 4 is connected to FEC1
3807 When set to -1, means to probe for first available.
3809 - CONFIG_FEC[12]_PHY_NORXERR
3810 The PHY does not have a RXERR line (RMII only).
3811 (so program the FEC to ignore it).
3814 Enable RMII mode for all FECs.
3815 Note that this is a global option, we can't
3816 have one FEC in standard MII mode and another in RMII mode.
3818 - CONFIG_CRC32_VERIFY
3819 Add a verify option to the crc32 command.
3822 => crc32 -v <address> <count> <crc32>
3824 Where address/count indicate a memory area
3825 and crc32 is the correct crc32 which the
3829 Add the "loopw" memory command. This only takes effect if
3830 the memory commands are activated globally (CONFIG_CMD_MEM).
3833 Add the "mdc" and "mwc" memory commands. These are cyclic
3838 This command will print 4 bytes (10,11,12,13) each 500 ms.
3840 => mwc.l 100 12345678 10
3841 This command will write 12345678 to address 100 all 10 ms.
3843 This only takes effect if the memory commands are activated
3844 globally (CONFIG_CMD_MEM).
3846 - CONFIG_SKIP_LOWLEVEL_INIT
3847 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3848 low level initializations (like setting up the memory
3849 controller) are omitted and/or U-Boot does not
3850 relocate itself into RAM.
3852 Normally this variable MUST NOT be defined. The only
3853 exception is when U-Boot is loaded (to RAM) by some
3854 other boot loader or by a debugger which performs
3855 these initializations itself.
3858 Modifies the behaviour of start.S when compiling a loader
3859 that is executed before the actual U-Boot. E.g. when
3860 compiling a NAND SPL.
3862 - CONFIG_ARCH_MAP_SYSMEM
3863 Generally U-Boot (and in particular the md command) uses
3864 effective address. It is therefore not necessary to regard
3865 U-Boot address as virtual addresses that need to be translated
3866 to physical addresses. However, sandbox requires this, since
3867 it maintains its own little RAM buffer which contains all
3868 addressable memory. This option causes some memory accesses
3869 to be mapped through map_sysmem() / unmap_sysmem().
3871 - CONFIG_USE_ARCH_MEMCPY
3872 CONFIG_USE_ARCH_MEMSET
3873 If these options are used a optimized version of memcpy/memset will
3874 be used if available. These functions may be faster under some
3875 conditions but may increase the binary size.
3877 - CONFIG_X86_RESET_VECTOR
3878 If defined, the x86 reset vector code is included. This is not
3879 needed when U-Boot is running from Coreboot.
3882 Defines the MPU clock speed (in MHz).
3884 NOTE : currently only supported on AM335x platforms.
3886 Freescale QE/FMAN Firmware Support:
3887 -----------------------------------
3889 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3890 loading of "firmware", which is encoded in the QE firmware binary format.
3891 This firmware often needs to be loaded during U-Boot booting, so macros
3892 are used to identify the storage device (NOR flash, SPI, etc) and the address
3895 - CONFIG_SYS_QE_FMAN_FW_ADDR
3896 The address in the storage device where the firmware is located. The
3897 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3900 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3901 The maximum possible size of the firmware. The firmware binary format
3902 has a field that specifies the actual size of the firmware, but it
3903 might not be possible to read any part of the firmware unless some
3904 local storage is allocated to hold the entire firmware first.
3906 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3907 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3908 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3909 virtual address in NOR flash.
3911 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3912 Specifies that QE/FMAN firmware is located in NAND flash.
3913 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3915 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3916 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3917 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3919 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3920 Specifies that QE/FMAN firmware is located on the primary SPI
3921 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3923 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3924 Specifies that QE/FMAN firmware is located in the remote (master)
3925 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3926 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3927 window->master inbound window->master LAW->the ucode address in
3928 master's memory space.
3930 Building the Software:
3931 ======================
3933 Building U-Boot has been tested in several native build environments
3934 and in many different cross environments. Of course we cannot support
3935 all possibly existing versions of cross development tools in all
3936 (potentially obsolete) versions. In case of tool chain problems we
3937 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3938 which is extensively used to build and test U-Boot.
3940 If you are not using a native environment, it is assumed that you
3941 have GNU cross compiling tools available in your path. In this case,
3942 you must set the environment variable CROSS_COMPILE in your shell.
3943 Note that no changes to the Makefile or any other source files are
3944 necessary. For example using the ELDK on a 4xx CPU, please enter:
3946 $ CROSS_COMPILE=ppc_4xx-
3947 $ export CROSS_COMPILE
3949 Note: If you wish to generate Windows versions of the utilities in
3950 the tools directory you can use the MinGW toolchain
3951 (http://www.mingw.org). Set your HOST tools to the MinGW
3952 toolchain and execute 'make tools'. For example:
3954 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3956 Binaries such as tools/mkimage.exe will be created which can
3957 be executed on computers running Windows.
3959 U-Boot is intended to be simple to build. After installing the
3960 sources you must configure U-Boot for one specific board type. This
3965 where "NAME_config" is the name of one of the existing configu-
3966 rations; see boards.cfg for supported names.
3968 Note: for some board special configuration names may exist; check if
3969 additional information is available from the board vendor; for
3970 instance, the TQM823L systems are available without (standard)
3971 or with LCD support. You can select such additional "features"
3972 when choosing the configuration, i. e.
3975 - will configure for a plain TQM823L, i. e. no LCD support
3977 make TQM823L_LCD_config
3978 - will configure for a TQM823L with U-Boot console on LCD
3983 Finally, type "make all", and you should get some working U-Boot
3984 images ready for download to / installation on your system:
3986 - "u-boot.bin" is a raw binary image
3987 - "u-boot" is an image in ELF binary format
3988 - "u-boot.srec" is in Motorola S-Record format
3990 By default the build is performed locally and the objects are saved
3991 in the source directory. One of the two methods can be used to change
3992 this behavior and build U-Boot to some external directory:
3994 1. Add O= to the make command line invocations:
3996 make O=/tmp/build distclean
3997 make O=/tmp/build NAME_config
3998 make O=/tmp/build all
4000 2. Set environment variable BUILD_DIR to point to the desired location:
4002 export BUILD_DIR=/tmp/build
4007 Note that the command line "O=" setting overrides the BUILD_DIR environment
4011 Please be aware that the Makefiles assume you are using GNU make, so
4012 for instance on NetBSD you might need to use "gmake" instead of
4016 If the system board that you have is not listed, then you will need
4017 to port U-Boot to your hardware platform. To do this, follow these
4020 1. Add a new configuration option for your board to the toplevel
4021 "boards.cfg" file, using the existing entries as examples.
4022 Follow the instructions there to keep the boards in order.
4023 2. Create a new directory to hold your board specific code. Add any
4024 files you need. In your board directory, you will need at least
4025 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4026 3. Create a new configuration file "include/configs/<board>.h" for
4028 3. If you're porting U-Boot to a new CPU, then also create a new
4029 directory to hold your CPU specific code. Add any files you need.
4030 4. Run "make <board>_config" with your new name.
4031 5. Type "make", and you should get a working "u-boot.srec" file
4032 to be installed on your target system.
4033 6. Debug and solve any problems that might arise.
4034 [Of course, this last step is much harder than it sounds.]
4037 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4038 ==============================================================
4040 If you have modified U-Boot sources (for instance added a new board
4041 or support for new devices, a new CPU, etc.) you are expected to
4042 provide feedback to the other developers. The feedback normally takes
4043 the form of a "patch", i. e. a context diff against a certain (latest
4044 official or latest in the git repository) version of U-Boot sources.
4046 But before you submit such a patch, please verify that your modifi-
4047 cation did not break existing code. At least make sure that *ALL* of
4048 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4049 just run the "MAKEALL" script, which will configure and build U-Boot
4050 for ALL supported system. Be warned, this will take a while. You can
4051 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4052 environment variable to the script, i. e. to use the ELDK cross tools
4055 CROSS_COMPILE=ppc_8xx- MAKEALL
4057 or to build on a native PowerPC system you can type
4059 CROSS_COMPILE=' ' MAKEALL
4061 When using the MAKEALL script, the default behaviour is to build
4062 U-Boot in the source directory. This location can be changed by
4063 setting the BUILD_DIR environment variable. Also, for each target
4064 built, the MAKEALL script saves two log files (<target>.ERR and
4065 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4066 location can be changed by setting the MAKEALL_LOGDIR environment
4067 variable. For example:
4069 export BUILD_DIR=/tmp/build
4070 export MAKEALL_LOGDIR=/tmp/log
4071 CROSS_COMPILE=ppc_8xx- MAKEALL
4073 With the above settings build objects are saved in the /tmp/build,
4074 log files are saved in the /tmp/log and the source tree remains clean
4075 during the whole build process.
4078 See also "U-Boot Porting Guide" below.
4081 Monitor Commands - Overview:
4082 ============================
4084 go - start application at address 'addr'
4085 run - run commands in an environment variable
4086 bootm - boot application image from memory
4087 bootp - boot image via network using BootP/TFTP protocol
4088 bootz - boot zImage from memory
4089 tftpboot- boot image via network using TFTP protocol
4090 and env variables "ipaddr" and "serverip"
4091 (and eventually "gatewayip")
4092 tftpput - upload a file via network using TFTP protocol
4093 rarpboot- boot image via network using RARP/TFTP protocol
4094 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4095 loads - load S-Record file over serial line
4096 loadb - load binary file over serial line (kermit mode)
4098 mm - memory modify (auto-incrementing)
4099 nm - memory modify (constant address)
4100 mw - memory write (fill)
4102 cmp - memory compare
4103 crc32 - checksum calculation
4104 i2c - I2C sub-system
4105 sspi - SPI utility commands
4106 base - print or set address offset
4107 printenv- print environment variables
4108 setenv - set environment variables
4109 saveenv - save environment variables to persistent storage
4110 protect - enable or disable FLASH write protection
4111 erase - erase FLASH memory
4112 flinfo - print FLASH memory information
4113 nand - NAND memory operations (see doc/README.nand)
4114 bdinfo - print Board Info structure
4115 iminfo - print header information for application image
4116 coninfo - print console devices and informations
4117 ide - IDE sub-system
4118 loop - infinite loop on address range
4119 loopw - infinite write loop on address range
4120 mtest - simple RAM test
4121 icache - enable or disable instruction cache
4122 dcache - enable or disable data cache
4123 reset - Perform RESET of the CPU
4124 echo - echo args to console
4125 version - print monitor version
4126 help - print online help
4127 ? - alias for 'help'
4130 Monitor Commands - Detailed Description:
4131 ========================================
4135 For now: just type "help <command>".
4138 Environment Variables:
4139 ======================
4141 U-Boot supports user configuration using Environment Variables which
4142 can be made persistent by saving to Flash memory.
4144 Environment Variables are set using "setenv", printed using
4145 "printenv", and saved to Flash using "saveenv". Using "setenv"
4146 without a value can be used to delete a variable from the
4147 environment. As long as you don't save the environment you are
4148 working with an in-memory copy. In case the Flash area containing the
4149 environment is erased by accident, a default environment is provided.
4151 Some configuration options can be set using Environment Variables.
4153 List of environment variables (most likely not complete):
4155 baudrate - see CONFIG_BAUDRATE
4157 bootdelay - see CONFIG_BOOTDELAY
4159 bootcmd - see CONFIG_BOOTCOMMAND
4161 bootargs - Boot arguments when booting an RTOS image
4163 bootfile - Name of the image to load with TFTP
4165 bootm_low - Memory range available for image processing in the bootm
4166 command can be restricted. This variable is given as
4167 a hexadecimal number and defines lowest address allowed
4168 for use by the bootm command. See also "bootm_size"
4169 environment variable. Address defined by "bootm_low" is
4170 also the base of the initial memory mapping for the Linux
4171 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4174 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4175 This variable is given as a hexadecimal number and it
4176 defines the size of the memory region starting at base
4177 address bootm_low that is accessible by the Linux kernel
4178 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4179 as the default value if it is defined, and bootm_size is
4182 bootm_size - Memory range available for image processing in the bootm
4183 command can be restricted. This variable is given as
4184 a hexadecimal number and defines the size of the region
4185 allowed for use by the bootm command. See also "bootm_low"
4186 environment variable.
4188 updatefile - Location of the software update file on a TFTP server, used
4189 by the automatic software update feature. Please refer to
4190 documentation in doc/README.update for more details.
4192 autoload - if set to "no" (any string beginning with 'n'),
4193 "bootp" will just load perform a lookup of the
4194 configuration from the BOOTP server, but not try to
4195 load any image using TFTP
4197 autostart - if set to "yes", an image loaded using the "bootp",
4198 "rarpboot", "tftpboot" or "diskboot" commands will
4199 be automatically started (by internally calling
4202 If set to "no", a standalone image passed to the
4203 "bootm" command will be copied to the load address
4204 (and eventually uncompressed), but NOT be started.
4205 This can be used to load and uncompress arbitrary
4208 fdt_high - if set this restricts the maximum address that the
4209 flattened device tree will be copied into upon boot.
4210 For example, if you have a system with 1 GB memory
4211 at physical address 0x10000000, while Linux kernel
4212 only recognizes the first 704 MB as low memory, you
4213 may need to set fdt_high as 0x3C000000 to have the
4214 device tree blob be copied to the maximum address
4215 of the 704 MB low memory, so that Linux kernel can
4216 access it during the boot procedure.
4218 If this is set to the special value 0xFFFFFFFF then
4219 the fdt will not be copied at all on boot. For this
4220 to work it must reside in writable memory, have
4221 sufficient padding on the end of it for u-boot to
4222 add the information it needs into it, and the memory
4223 must be accessible by the kernel.
4225 fdtcontroladdr- if set this is the address of the control flattened
4226 device tree used by U-Boot when CONFIG_OF_CONTROL is
4229 i2cfast - (PPC405GP|PPC405EP only)
4230 if set to 'y' configures Linux I2C driver for fast
4231 mode (400kHZ). This environment variable is used in
4232 initialization code. So, for changes to be effective
4233 it must be saved and board must be reset.
4235 initrd_high - restrict positioning of initrd images:
4236 If this variable is not set, initrd images will be
4237 copied to the highest possible address in RAM; this
4238 is usually what you want since it allows for
4239 maximum initrd size. If for some reason you want to
4240 make sure that the initrd image is loaded below the
4241 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4242 variable to a value of "no" or "off" or "0".
4243 Alternatively, you can set it to a maximum upper
4244 address to use (U-Boot will still check that it
4245 does not overwrite the U-Boot stack and data).
4247 For instance, when you have a system with 16 MB
4248 RAM, and want to reserve 4 MB from use by Linux,
4249 you can do this by adding "mem=12M" to the value of
4250 the "bootargs" variable. However, now you must make
4251 sure that the initrd image is placed in the first
4252 12 MB as well - this can be done with
4254 setenv initrd_high 00c00000
4256 If you set initrd_high to 0xFFFFFFFF, this is an
4257 indication to U-Boot that all addresses are legal
4258 for the Linux kernel, including addresses in flash
4259 memory. In this case U-Boot will NOT COPY the
4260 ramdisk at all. This may be useful to reduce the
4261 boot time on your system, but requires that this
4262 feature is supported by your Linux kernel.
4264 ipaddr - IP address; needed for tftpboot command
4266 loadaddr - Default load address for commands like "bootp",
4267 "rarpboot", "tftpboot", "loadb" or "diskboot"
4269 loads_echo - see CONFIG_LOADS_ECHO
4271 serverip - TFTP server IP address; needed for tftpboot command
4273 bootretry - see CONFIG_BOOT_RETRY_TIME
4275 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4277 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4279 ethprime - controls which interface is used first.
4281 ethact - controls which interface is currently active.
4282 For example you can do the following
4284 => setenv ethact FEC
4285 => ping 192.168.0.1 # traffic sent on FEC
4286 => setenv ethact SCC
4287 => ping 10.0.0.1 # traffic sent on SCC
4289 ethrotate - When set to "no" U-Boot does not go through all
4290 available network interfaces.
4291 It just stays at the currently selected interface.
4293 netretry - When set to "no" each network operation will
4294 either succeed or fail without retrying.
4295 When set to "once" the network operation will
4296 fail when all the available network interfaces
4297 are tried once without success.
4298 Useful on scripts which control the retry operation
4301 npe_ucode - set load address for the NPE microcode
4303 tftpsrcport - If this is set, the value is used for TFTP's
4306 tftpdstport - If this is set, the value is used for TFTP's UDP
4307 destination port instead of the Well Know Port 69.
4309 tftpblocksize - Block size to use for TFTP transfers; if not set,
4310 we use the TFTP server's default block size
4312 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4313 seconds, minimum value is 1000 = 1 second). Defines
4314 when a packet is considered to be lost so it has to
4315 be retransmitted. The default is 5000 = 5 seconds.
4316 Lowering this value may make downloads succeed
4317 faster in networks with high packet loss rates or
4318 with unreliable TFTP servers.
4320 vlan - When set to a value < 4095 the traffic over
4321 Ethernet is encapsulated/received over 802.1q
4324 The following image location variables contain the location of images
4325 used in booting. The "Image" column gives the role of the image and is
4326 not an environment variable name. The other columns are environment
4327 variable names. "File Name" gives the name of the file on a TFTP
4328 server, "RAM Address" gives the location in RAM the image will be
4329 loaded to, and "Flash Location" gives the image's address in NOR
4330 flash or offset in NAND flash.
4332 *Note* - these variables don't have to be defined for all boards, some
4333 boards currenlty use other variables for these purposes, and some
4334 boards use these variables for other purposes.
4336 Image File Name RAM Address Flash Location
4337 ----- --------- ----------- --------------
4338 u-boot u-boot u-boot_addr_r u-boot_addr
4339 Linux kernel bootfile kernel_addr_r kernel_addr
4340 device tree blob fdtfile fdt_addr_r fdt_addr
4341 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4343 The following environment variables may be used and automatically
4344 updated by the network boot commands ("bootp" and "rarpboot"),
4345 depending the information provided by your boot server:
4347 bootfile - see above
4348 dnsip - IP address of your Domain Name Server
4349 dnsip2 - IP address of your secondary Domain Name Server
4350 gatewayip - IP address of the Gateway (Router) to use
4351 hostname - Target hostname
4353 netmask - Subnet Mask
4354 rootpath - Pathname of the root filesystem on the NFS server
4355 serverip - see above
4358 There are two special Environment Variables:
4360 serial# - contains hardware identification information such
4361 as type string and/or serial number
4362 ethaddr - Ethernet address
4364 These variables can be set only once (usually during manufacturing of
4365 the board). U-Boot refuses to delete or overwrite these variables
4366 once they have been set once.
4369 Further special Environment Variables:
4371 ver - Contains the U-Boot version string as printed
4372 with the "version" command. This variable is
4373 readonly (see CONFIG_VERSION_VARIABLE).
4376 Please note that changes to some configuration parameters may take
4377 only effect after the next boot (yes, that's just like Windoze :-).
4380 Callback functions for environment variables:
4381 ---------------------------------------------
4383 For some environment variables, the behavior of u-boot needs to change
4384 when their values are changed. This functionailty allows functions to
4385 be associated with arbitrary variables. On creation, overwrite, or
4386 deletion, the callback will provide the opportunity for some side
4387 effect to happen or for the change to be rejected.
4389 The callbacks are named and associated with a function using the
4390 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4392 These callbacks are associated with variables in one of two ways. The
4393 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4394 in the board configuration to a string that defines a list of
4395 associations. The list must be in the following format:
4397 entry = variable_name[:callback_name]
4400 If the callback name is not specified, then the callback is deleted.
4401 Spaces are also allowed anywhere in the list.
4403 Callbacks can also be associated by defining the ".callbacks" variable
4404 with the same list format above. Any association in ".callbacks" will
4405 override any association in the static list. You can define
4406 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4407 ".callbacks" envirnoment variable in the default or embedded environment.
4410 Command Line Parsing:
4411 =====================
4413 There are two different command line parsers available with U-Boot:
4414 the old "simple" one, and the much more powerful "hush" shell:
4416 Old, simple command line parser:
4417 --------------------------------
4419 - supports environment variables (through setenv / saveenv commands)
4420 - several commands on one line, separated by ';'
4421 - variable substitution using "... ${name} ..." syntax
4422 - special characters ('$', ';') can be escaped by prefixing with '\',
4424 setenv bootcmd bootm \${address}
4425 - You can also escape text by enclosing in single apostrophes, for example:
4426 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4431 - similar to Bourne shell, with control structures like
4432 if...then...else...fi, for...do...done; while...do...done,
4433 until...do...done, ...
4434 - supports environment ("global") variables (through setenv / saveenv
4435 commands) and local shell variables (through standard shell syntax
4436 "name=value"); only environment variables can be used with "run"
4442 (1) If a command line (or an environment variable executed by a "run"
4443 command) contains several commands separated by semicolon, and
4444 one of these commands fails, then the remaining commands will be
4447 (2) If you execute several variables with one call to run (i. e.
4448 calling run with a list of variables as arguments), any failing
4449 command will cause "run" to terminate, i. e. the remaining
4450 variables are not executed.
4452 Note for Redundant Ethernet Interfaces:
4453 =======================================
4455 Some boards come with redundant Ethernet interfaces; U-Boot supports
4456 such configurations and is capable of automatic selection of a
4457 "working" interface when needed. MAC assignment works as follows:
4459 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4460 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4461 "eth1addr" (=>eth1), "eth2addr", ...
4463 If the network interface stores some valid MAC address (for instance
4464 in SROM), this is used as default address if there is NO correspon-
4465 ding setting in the environment; if the corresponding environment
4466 variable is set, this overrides the settings in the card; that means:
4468 o If the SROM has a valid MAC address, and there is no address in the
4469 environment, the SROM's address is used.
4471 o If there is no valid address in the SROM, and a definition in the
4472 environment exists, then the value from the environment variable is
4475 o If both the SROM and the environment contain a MAC address, and
4476 both addresses are the same, this MAC address is used.
4478 o If both the SROM and the environment contain a MAC address, and the
4479 addresses differ, the value from the environment is used and a
4482 o If neither SROM nor the environment contain a MAC address, an error
4485 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4486 will be programmed into hardware as part of the initialization process. This
4487 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4488 The naming convention is as follows:
4489 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4494 U-Boot is capable of booting (and performing other auxiliary operations on)
4495 images in two formats:
4497 New uImage format (FIT)
4498 -----------------------
4500 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4501 to Flattened Device Tree). It allows the use of images with multiple
4502 components (several kernels, ramdisks, etc.), with contents protected by
4503 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4509 Old image format is based on binary files which can be basically anything,
4510 preceded by a special header; see the definitions in include/image.h for
4511 details; basically, the header defines the following image properties:
4513 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4514 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4515 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4516 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4518 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4519 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4520 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4521 * Compression Type (uncompressed, gzip, bzip2)
4527 The header is marked by a special Magic Number, and both the header
4528 and the data portions of the image are secured against corruption by
4535 Although U-Boot should support any OS or standalone application
4536 easily, the main focus has always been on Linux during the design of
4539 U-Boot includes many features that so far have been part of some
4540 special "boot loader" code within the Linux kernel. Also, any
4541 "initrd" images to be used are no longer part of one big Linux image;
4542 instead, kernel and "initrd" are separate images. This implementation
4543 serves several purposes:
4545 - the same features can be used for other OS or standalone
4546 applications (for instance: using compressed images to reduce the
4547 Flash memory footprint)
4549 - it becomes much easier to port new Linux kernel versions because
4550 lots of low-level, hardware dependent stuff are done by U-Boot
4552 - the same Linux kernel image can now be used with different "initrd"
4553 images; of course this also means that different kernel images can
4554 be run with the same "initrd". This makes testing easier (you don't
4555 have to build a new "zImage.initrd" Linux image when you just
4556 change a file in your "initrd"). Also, a field-upgrade of the
4557 software is easier now.
4563 Porting Linux to U-Boot based systems:
4564 ---------------------------------------
4566 U-Boot cannot save you from doing all the necessary modifications to
4567 configure the Linux device drivers for use with your target hardware
4568 (no, we don't intend to provide a full virtual machine interface to
4571 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4573 Just make sure your machine specific header file (for instance
4574 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4575 Information structure as we define in include/asm-<arch>/u-boot.h,
4576 and make sure that your definition of IMAP_ADDR uses the same value
4577 as your U-Boot configuration in CONFIG_SYS_IMMR.
4580 Configuring the Linux kernel:
4581 -----------------------------
4583 No specific requirements for U-Boot. Make sure you have some root
4584 device (initial ramdisk, NFS) for your target system.
4587 Building a Linux Image:
4588 -----------------------
4590 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4591 not used. If you use recent kernel source, a new build target
4592 "uImage" will exist which automatically builds an image usable by
4593 U-Boot. Most older kernels also have support for a "pImage" target,
4594 which was introduced for our predecessor project PPCBoot and uses a
4595 100% compatible format.
4604 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4605 encapsulate a compressed Linux kernel image with header information,
4606 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4608 * build a standard "vmlinux" kernel image (in ELF binary format):
4610 * convert the kernel into a raw binary image:
4612 ${CROSS_COMPILE}-objcopy -O binary \
4613 -R .note -R .comment \
4614 -S vmlinux linux.bin
4616 * compress the binary image:
4620 * package compressed binary image for U-Boot:
4622 mkimage -A ppc -O linux -T kernel -C gzip \
4623 -a 0 -e 0 -n "Linux Kernel Image" \
4624 -d linux.bin.gz uImage
4627 The "mkimage" tool can also be used to create ramdisk images for use
4628 with U-Boot, either separated from the Linux kernel image, or
4629 combined into one file. "mkimage" encapsulates the images with a 64
4630 byte header containing information about target architecture,
4631 operating system, image type, compression method, entry points, time
4632 stamp, CRC32 checksums, etc.
4634 "mkimage" can be called in two ways: to verify existing images and
4635 print the header information, or to build new images.
4637 In the first form (with "-l" option) mkimage lists the information
4638 contained in the header of an existing U-Boot image; this includes
4639 checksum verification:
4641 tools/mkimage -l image
4642 -l ==> list image header information
4644 The second form (with "-d" option) is used to build a U-Boot image
4645 from a "data file" which is used as image payload:
4647 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4648 -n name -d data_file image
4649 -A ==> set architecture to 'arch'
4650 -O ==> set operating system to 'os'
4651 -T ==> set image type to 'type'
4652 -C ==> set compression type 'comp'
4653 -a ==> set load address to 'addr' (hex)
4654 -e ==> set entry point to 'ep' (hex)
4655 -n ==> set image name to 'name'
4656 -d ==> use image data from 'datafile'
4658 Right now, all Linux kernels for PowerPC systems use the same load
4659 address (0x00000000), but the entry point address depends on the
4662 - 2.2.x kernels have the entry point at 0x0000000C,
4663 - 2.3.x and later kernels have the entry point at 0x00000000.
4665 So a typical call to build a U-Boot image would read:
4667 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4668 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4669 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4670 > examples/uImage.TQM850L
4671 Image Name: 2.4.4 kernel for TQM850L
4672 Created: Wed Jul 19 02:34:59 2000
4673 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4674 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4675 Load Address: 0x00000000
4676 Entry Point: 0x00000000
4678 To verify the contents of the image (or check for corruption):
4680 -> tools/mkimage -l examples/uImage.TQM850L
4681 Image Name: 2.4.4 kernel for TQM850L
4682 Created: Wed Jul 19 02:34:59 2000
4683 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4684 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4685 Load Address: 0x00000000
4686 Entry Point: 0x00000000
4688 NOTE: for embedded systems where boot time is critical you can trade
4689 speed for memory and install an UNCOMPRESSED image instead: this
4690 needs more space in Flash, but boots much faster since it does not
4691 need to be uncompressed:
4693 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4694 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4695 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4696 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4697 > examples/uImage.TQM850L-uncompressed
4698 Image Name: 2.4.4 kernel for TQM850L
4699 Created: Wed Jul 19 02:34:59 2000
4700 Image Type: PowerPC Linux Kernel Image (uncompressed)
4701 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4702 Load Address: 0x00000000
4703 Entry Point: 0x00000000
4706 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4707 when your kernel is intended to use an initial ramdisk:
4709 -> tools/mkimage -n 'Simple Ramdisk Image' \
4710 > -A ppc -O linux -T ramdisk -C gzip \
4711 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4712 Image Name: Simple Ramdisk Image
4713 Created: Wed Jan 12 14:01:50 2000
4714 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4715 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4716 Load Address: 0x00000000
4717 Entry Point: 0x00000000
4720 Installing a Linux Image:
4721 -------------------------
4723 To downloading a U-Boot image over the serial (console) interface,
4724 you must convert the image to S-Record format:
4726 objcopy -I binary -O srec examples/image examples/image.srec
4728 The 'objcopy' does not understand the information in the U-Boot
4729 image header, so the resulting S-Record file will be relative to
4730 address 0x00000000. To load it to a given address, you need to
4731 specify the target address as 'offset' parameter with the 'loads'
4734 Example: install the image to address 0x40100000 (which on the
4735 TQM8xxL is in the first Flash bank):
4737 => erase 40100000 401FFFFF
4743 ## Ready for S-Record download ...
4744 ~>examples/image.srec
4745 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4747 15989 15990 15991 15992
4748 [file transfer complete]
4750 ## Start Addr = 0x00000000
4753 You can check the success of the download using the 'iminfo' command;
4754 this includes a checksum verification so you can be sure no data
4755 corruption happened:
4759 ## Checking Image at 40100000 ...
4760 Image Name: 2.2.13 for initrd on TQM850L
4761 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4762 Data Size: 335725 Bytes = 327 kB = 0 MB
4763 Load Address: 00000000
4764 Entry Point: 0000000c
4765 Verifying Checksum ... OK
4771 The "bootm" command is used to boot an application that is stored in
4772 memory (RAM or Flash). In case of a Linux kernel image, the contents
4773 of the "bootargs" environment variable is passed to the kernel as
4774 parameters. You can check and modify this variable using the
4775 "printenv" and "setenv" commands:
4778 => printenv bootargs
4779 bootargs=root=/dev/ram
4781 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4783 => printenv bootargs
4784 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4787 ## Booting Linux kernel at 40020000 ...
4788 Image Name: 2.2.13 for NFS on TQM850L
4789 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4790 Data Size: 381681 Bytes = 372 kB = 0 MB
4791 Load Address: 00000000
4792 Entry Point: 0000000c
4793 Verifying Checksum ... OK
4794 Uncompressing Kernel Image ... OK
4795 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
4796 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4797 time_init: decrementer frequency = 187500000/60
4798 Calibrating delay loop... 49.77 BogoMIPS
4799 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4802 If you want to boot a Linux kernel with initial RAM disk, you pass
4803 the memory addresses of both the kernel and the initrd image (PPBCOOT
4804 format!) to the "bootm" command:
4806 => imi 40100000 40200000
4808 ## Checking Image at 40100000 ...
4809 Image Name: 2.2.13 for initrd on TQM850L
4810 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4811 Data Size: 335725 Bytes = 327 kB = 0 MB
4812 Load Address: 00000000
4813 Entry Point: 0000000c
4814 Verifying Checksum ... OK
4816 ## Checking Image at 40200000 ...
4817 Image Name: Simple Ramdisk Image
4818 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4819 Data Size: 566530 Bytes = 553 kB = 0 MB
4820 Load Address: 00000000
4821 Entry Point: 00000000
4822 Verifying Checksum ... OK
4824 => bootm 40100000 40200000
4825 ## Booting Linux kernel at 40100000 ...
4826 Image Name: 2.2.13 for initrd on TQM850L
4827 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4828 Data Size: 335725 Bytes = 327 kB = 0 MB
4829 Load Address: 00000000
4830 Entry Point: 0000000c
4831 Verifying Checksum ... OK
4832 Uncompressing Kernel Image ... OK
4833 ## Loading RAMDisk Image at 40200000 ...
4834 Image Name: Simple Ramdisk Image
4835 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4836 Data Size: 566530 Bytes = 553 kB = 0 MB
4837 Load Address: 00000000
4838 Entry Point: 00000000
4839 Verifying Checksum ... OK
4840 Loading Ramdisk ... OK
4841 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
4842 Boot arguments: root=/dev/ram
4843 time_init: decrementer frequency = 187500000/60
4844 Calibrating delay loop... 49.77 BogoMIPS
4846 RAMDISK: Compressed image found at block 0
4847 VFS: Mounted root (ext2 filesystem).
4851 Boot Linux and pass a flat device tree:
4854 First, U-Boot must be compiled with the appropriate defines. See the section
4855 titled "Linux Kernel Interface" above for a more in depth explanation. The
4856 following is an example of how to start a kernel and pass an updated
4862 oft=oftrees/mpc8540ads.dtb
4863 => tftp $oftaddr $oft
4864 Speed: 1000, full duplex
4866 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4867 Filename 'oftrees/mpc8540ads.dtb'.
4868 Load address: 0x300000
4871 Bytes transferred = 4106 (100a hex)
4872 => tftp $loadaddr $bootfile
4873 Speed: 1000, full duplex
4875 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4877 Load address: 0x200000
4878 Loading:############
4880 Bytes transferred = 1029407 (fb51f hex)
4885 => bootm $loadaddr - $oftaddr
4886 ## Booting image at 00200000 ...
4887 Image Name: Linux-2.6.17-dirty
4888 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4889 Data Size: 1029343 Bytes = 1005.2 kB
4890 Load Address: 00000000
4891 Entry Point: 00000000
4892 Verifying Checksum ... OK
4893 Uncompressing Kernel Image ... OK
4894 Booting using flat device tree at 0x300000
4895 Using MPC85xx ADS machine description
4896 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4900 More About U-Boot Image Types:
4901 ------------------------------
4903 U-Boot supports the following image types:
4905 "Standalone Programs" are directly runnable in the environment
4906 provided by U-Boot; it is expected that (if they behave
4907 well) you can continue to work in U-Boot after return from
4908 the Standalone Program.
4909 "OS Kernel Images" are usually images of some Embedded OS which
4910 will take over control completely. Usually these programs
4911 will install their own set of exception handlers, device
4912 drivers, set up the MMU, etc. - this means, that you cannot
4913 expect to re-enter U-Boot except by resetting the CPU.
4914 "RAMDisk Images" are more or less just data blocks, and their
4915 parameters (address, size) are passed to an OS kernel that is
4917 "Multi-File Images" contain several images, typically an OS
4918 (Linux) kernel image and one or more data images like
4919 RAMDisks. This construct is useful for instance when you want
4920 to boot over the network using BOOTP etc., where the boot
4921 server provides just a single image file, but you want to get
4922 for instance an OS kernel and a RAMDisk image.
4924 "Multi-File Images" start with a list of image sizes, each
4925 image size (in bytes) specified by an "uint32_t" in network
4926 byte order. This list is terminated by an "(uint32_t)0".
4927 Immediately after the terminating 0 follow the images, one by
4928 one, all aligned on "uint32_t" boundaries (size rounded up to
4929 a multiple of 4 bytes).
4931 "Firmware Images" are binary images containing firmware (like
4932 U-Boot or FPGA images) which usually will be programmed to
4935 "Script files" are command sequences that will be executed by
4936 U-Boot's command interpreter; this feature is especially
4937 useful when you configure U-Boot to use a real shell (hush)
4938 as command interpreter.
4940 Booting the Linux zImage:
4941 -------------------------
4943 On some platforms, it's possible to boot Linux zImage. This is done
4944 using the "bootz" command. The syntax of "bootz" command is the same
4945 as the syntax of "bootm" command.
4947 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4948 kernel with raw initrd images. The syntax is slightly different, the
4949 address of the initrd must be augmented by it's size, in the following
4950 format: "<initrd addres>:<initrd size>".
4956 One of the features of U-Boot is that you can dynamically load and
4957 run "standalone" applications, which can use some resources of
4958 U-Boot like console I/O functions or interrupt services.
4960 Two simple examples are included with the sources:
4965 'examples/hello_world.c' contains a small "Hello World" Demo
4966 application; it is automatically compiled when you build U-Boot.
4967 It's configured to run at address 0x00040004, so you can play with it
4971 ## Ready for S-Record download ...
4972 ~>examples/hello_world.srec
4973 1 2 3 4 5 6 7 8 9 10 11 ...
4974 [file transfer complete]
4976 ## Start Addr = 0x00040004
4978 => go 40004 Hello World! This is a test.
4979 ## Starting application at 0x00040004 ...
4990 Hit any key to exit ...
4992 ## Application terminated, rc = 0x0
4994 Another example, which demonstrates how to register a CPM interrupt
4995 handler with the U-Boot code, can be found in 'examples/timer.c'.
4996 Here, a CPM timer is set up to generate an interrupt every second.
4997 The interrupt service routine is trivial, just printing a '.'
4998 character, but this is just a demo program. The application can be
4999 controlled by the following keys:
5001 ? - print current values og the CPM Timer registers
5002 b - enable interrupts and start timer
5003 e - stop timer and disable interrupts
5004 q - quit application
5007 ## Ready for S-Record download ...
5008 ~>examples/timer.srec
5009 1 2 3 4 5 6 7 8 9 10 11 ...
5010 [file transfer complete]
5012 ## Start Addr = 0x00040004
5015 ## Starting application at 0x00040004 ...
5018 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5021 [q, b, e, ?] Set interval 1000000 us
5024 [q, b, e, ?] ........
5025 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5028 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5031 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5034 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5036 [q, b, e, ?] ...Stopping timer
5038 [q, b, e, ?] ## Application terminated, rc = 0x0
5044 Over time, many people have reported problems when trying to use the
5045 "minicom" terminal emulation program for serial download. I (wd)
5046 consider minicom to be broken, and recommend not to use it. Under
5047 Unix, I recommend to use C-Kermit for general purpose use (and
5048 especially for kermit binary protocol download ("loadb" command), and
5049 use "cu" for S-Record download ("loads" command). See
5050 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5051 for help with kermit.
5054 Nevertheless, if you absolutely want to use it try adding this
5055 configuration to your "File transfer protocols" section:
5057 Name Program Name U/D FullScr IO-Red. Multi
5058 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5059 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5065 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5066 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5068 Building requires a cross environment; it is known to work on
5069 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5070 need gmake since the Makefiles are not compatible with BSD make).
5071 Note that the cross-powerpc package does not install include files;
5072 attempting to build U-Boot will fail because <machine/ansi.h> is
5073 missing. This file has to be installed and patched manually:
5075 # cd /usr/pkg/cross/powerpc-netbsd/include
5077 # ln -s powerpc machine
5078 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5079 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5081 Native builds *don't* work due to incompatibilities between native
5082 and U-Boot include files.
5084 Booting assumes that (the first part of) the image booted is a
5085 stage-2 loader which in turn loads and then invokes the kernel
5086 proper. Loader sources will eventually appear in the NetBSD source
5087 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5088 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5091 Implementation Internals:
5092 =========================
5094 The following is not intended to be a complete description of every
5095 implementation detail. However, it should help to understand the
5096 inner workings of U-Boot and make it easier to port it to custom
5100 Initial Stack, Global Data:
5101 ---------------------------
5103 The implementation of U-Boot is complicated by the fact that U-Boot
5104 starts running out of ROM (flash memory), usually without access to
5105 system RAM (because the memory controller is not initialized yet).
5106 This means that we don't have writable Data or BSS segments, and BSS
5107 is not initialized as zero. To be able to get a C environment working
5108 at all, we have to allocate at least a minimal stack. Implementation
5109 options for this are defined and restricted by the CPU used: Some CPU
5110 models provide on-chip memory (like the IMMR area on MPC8xx and
5111 MPC826x processors), on others (parts of) the data cache can be
5112 locked as (mis-) used as memory, etc.
5114 Chris Hallinan posted a good summary of these issues to the
5115 U-Boot mailing list:
5117 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5118 From: "Chris Hallinan" <clh@net1plus.com>
5119 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5122 Correct me if I'm wrong, folks, but the way I understand it
5123 is this: Using DCACHE as initial RAM for Stack, etc, does not
5124 require any physical RAM backing up the cache. The cleverness
5125 is that the cache is being used as a temporary supply of
5126 necessary storage before the SDRAM controller is setup. It's
5127 beyond the scope of this list to explain the details, but you
5128 can see how this works by studying the cache architecture and
5129 operation in the architecture and processor-specific manuals.
5131 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5132 is another option for the system designer to use as an
5133 initial stack/RAM area prior to SDRAM being available. Either
5134 option should work for you. Using CS 4 should be fine if your
5135 board designers haven't used it for something that would
5136 cause you grief during the initial boot! It is frequently not
5139 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5140 with your processor/board/system design. The default value
5141 you will find in any recent u-boot distribution in
5142 walnut.h should work for you. I'd set it to a value larger
5143 than your SDRAM module. If you have a 64MB SDRAM module, set
5144 it above 400_0000. Just make sure your board has no resources
5145 that are supposed to respond to that address! That code in
5146 start.S has been around a while and should work as is when
5147 you get the config right.
5152 It is essential to remember this, since it has some impact on the C
5153 code for the initialization procedures:
5155 * Initialized global data (data segment) is read-only. Do not attempt
5158 * Do not use any uninitialized global data (or implicitely initialized
5159 as zero data - BSS segment) at all - this is undefined, initiali-
5160 zation is performed later (when relocating to RAM).
5162 * Stack space is very limited. Avoid big data buffers or things like
5165 Having only the stack as writable memory limits means we cannot use
5166 normal global data to share information beween the code. But it
5167 turned out that the implementation of U-Boot can be greatly
5168 simplified by making a global data structure (gd_t) available to all
5169 functions. We could pass a pointer to this data as argument to _all_
5170 functions, but this would bloat the code. Instead we use a feature of
5171 the GCC compiler (Global Register Variables) to share the data: we
5172 place a pointer (gd) to the global data into a register which we
5173 reserve for this purpose.
5175 When choosing a register for such a purpose we are restricted by the
5176 relevant (E)ABI specifications for the current architecture, and by
5177 GCC's implementation.
5179 For PowerPC, the following registers have specific use:
5181 R2: reserved for system use
5182 R3-R4: parameter passing and return values
5183 R5-R10: parameter passing
5184 R13: small data area pointer
5188 (U-Boot also uses R12 as internal GOT pointer. r12
5189 is a volatile register so r12 needs to be reset when
5190 going back and forth between asm and C)
5192 ==> U-Boot will use R2 to hold a pointer to the global data
5194 Note: on PPC, we could use a static initializer (since the
5195 address of the global data structure is known at compile time),
5196 but it turned out that reserving a register results in somewhat
5197 smaller code - although the code savings are not that big (on
5198 average for all boards 752 bytes for the whole U-Boot image,
5199 624 text + 127 data).
5201 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5202 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5204 ==> U-Boot will use P3 to hold a pointer to the global data
5206 On ARM, the following registers are used:
5208 R0: function argument word/integer result
5209 R1-R3: function argument word
5211 R10: stack limit (used only if stack checking if enabled)
5212 R11: argument (frame) pointer
5213 R12: temporary workspace
5216 R15: program counter
5218 ==> U-Boot will use R8 to hold a pointer to the global data
5220 On Nios II, the ABI is documented here:
5221 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5223 ==> U-Boot will use gp to hold a pointer to the global data
5225 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5226 to access small data sections, so gp is free.
5228 On NDS32, the following registers are used:
5230 R0-R1: argument/return
5232 R15: temporary register for assembler
5233 R16: trampoline register
5234 R28: frame pointer (FP)
5235 R29: global pointer (GP)
5236 R30: link register (LP)
5237 R31: stack pointer (SP)
5238 PC: program counter (PC)
5240 ==> U-Boot will use R10 to hold a pointer to the global data
5242 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5243 or current versions of GCC may "optimize" the code too much.
5248 U-Boot runs in system state and uses physical addresses, i.e. the
5249 MMU is not used either for address mapping nor for memory protection.
5251 The available memory is mapped to fixed addresses using the memory
5252 controller. In this process, a contiguous block is formed for each
5253 memory type (Flash, SDRAM, SRAM), even when it consists of several
5254 physical memory banks.
5256 U-Boot is installed in the first 128 kB of the first Flash bank (on
5257 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5258 booting and sizing and initializing DRAM, the code relocates itself
5259 to the upper end of DRAM. Immediately below the U-Boot code some
5260 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5261 configuration setting]. Below that, a structure with global Board
5262 Info data is placed, followed by the stack (growing downward).
5264 Additionally, some exception handler code is copied to the low 8 kB
5265 of DRAM (0x00000000 ... 0x00001FFF).
5267 So a typical memory configuration with 16 MB of DRAM could look like
5270 0x0000 0000 Exception Vector code
5273 0x0000 2000 Free for Application Use
5279 0x00FB FF20 Monitor Stack (Growing downward)
5280 0x00FB FFAC Board Info Data and permanent copy of global data
5281 0x00FC 0000 Malloc Arena
5284 0x00FE 0000 RAM Copy of Monitor Code
5285 ... eventually: LCD or video framebuffer
5286 ... eventually: pRAM (Protected RAM - unchanged by reset)
5287 0x00FF FFFF [End of RAM]
5290 System Initialization:
5291 ----------------------
5293 In the reset configuration, U-Boot starts at the reset entry point
5294 (on most PowerPC systems at address 0x00000100). Because of the reset
5295 configuration for CS0# this is a mirror of the onboard Flash memory.
5296 To be able to re-map memory U-Boot then jumps to its link address.
5297 To be able to implement the initialization code in C, a (small!)
5298 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5299 which provide such a feature like MPC8xx or MPC8260), or in a locked
5300 part of the data cache. After that, U-Boot initializes the CPU core,
5301 the caches and the SIU.
5303 Next, all (potentially) available memory banks are mapped using a
5304 preliminary mapping. For example, we put them on 512 MB boundaries
5305 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5306 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5307 programmed for SDRAM access. Using the temporary configuration, a
5308 simple memory test is run that determines the size of the SDRAM
5311 When there is more than one SDRAM bank, and the banks are of
5312 different size, the largest is mapped first. For equal size, the first
5313 bank (CS2#) is mapped first. The first mapping is always for address
5314 0x00000000, with any additional banks following immediately to create
5315 contiguous memory starting from 0.
5317 Then, the monitor installs itself at the upper end of the SDRAM area
5318 and allocates memory for use by malloc() and for the global Board
5319 Info data; also, the exception vector code is copied to the low RAM
5320 pages, and the final stack is set up.
5322 Only after this relocation will you have a "normal" C environment;
5323 until that you are restricted in several ways, mostly because you are
5324 running from ROM, and because the code will have to be relocated to a
5328 U-Boot Porting Guide:
5329 ----------------------
5331 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5335 int main(int argc, char *argv[])
5337 sighandler_t no_more_time;
5339 signal(SIGALRM, no_more_time);
5340 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5342 if (available_money > available_manpower) {
5343 Pay consultant to port U-Boot;
5347 Download latest U-Boot source;
5349 Subscribe to u-boot mailing list;
5352 email("Hi, I am new to U-Boot, how do I get started?");
5355 Read the README file in the top level directory;
5356 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5357 Read applicable doc/*.README;
5358 Read the source, Luke;
5359 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5362 if (available_money > toLocalCurrency ($2500))
5365 Add a lot of aggravation and time;
5367 if (a similar board exists) { /* hopefully... */
5368 cp -a board/<similar> board/<myboard>
5369 cp include/configs/<similar>.h include/configs/<myboard>.h
5371 Create your own board support subdirectory;
5372 Create your own board include/configs/<myboard>.h file;
5374 Edit new board/<myboard> files
5375 Edit new include/configs/<myboard>.h
5380 Add / modify source code;
5384 email("Hi, I am having problems...");
5386 Send patch file to the U-Boot email list;
5387 if (reasonable critiques)
5388 Incorporate improvements from email list code review;
5390 Defend code as written;
5396 void no_more_time (int sig)
5405 All contributions to U-Boot should conform to the Linux kernel
5406 coding style; see the file "Documentation/CodingStyle" and the script
5407 "scripts/Lindent" in your Linux kernel source directory.
5409 Source files originating from a different project (for example the
5410 MTD subsystem) are generally exempt from these guidelines and are not
5411 reformated to ease subsequent migration to newer versions of those
5414 Please note that U-Boot is implemented in C (and to some small parts in
5415 Assembler); no C++ is used, so please do not use C++ style comments (//)
5418 Please also stick to the following formatting rules:
5419 - remove any trailing white space
5420 - use TAB characters for indentation and vertical alignment, not spaces
5421 - make sure NOT to use DOS '\r\n' line feeds
5422 - do not add more than 2 consecutive empty lines to source files
5423 - do not add trailing empty lines to source files
5425 Submissions which do not conform to the standards may be returned
5426 with a request to reformat the changes.
5432 Since the number of patches for U-Boot is growing, we need to
5433 establish some rules. Submissions which do not conform to these rules
5434 may be rejected, even when they contain important and valuable stuff.
5436 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5438 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5439 see http://lists.denx.de/mailman/listinfo/u-boot
5441 When you send a patch, please include the following information with
5444 * For bug fixes: a description of the bug and how your patch fixes
5445 this bug. Please try to include a way of demonstrating that the
5446 patch actually fixes something.
5448 * For new features: a description of the feature and your
5451 * A CHANGELOG entry as plaintext (separate from the patch)
5453 * For major contributions, your entry to the CREDITS file
5455 * When you add support for a new board, don't forget to add this
5456 board to the MAINTAINERS file, too.
5458 * If your patch adds new configuration options, don't forget to
5459 document these in the README file.
5461 * The patch itself. If you are using git (which is *strongly*
5462 recommended) you can easily generate the patch using the
5463 "git format-patch". If you then use "git send-email" to send it to
5464 the U-Boot mailing list, you will avoid most of the common problems
5465 with some other mail clients.
5467 If you cannot use git, use "diff -purN OLD NEW". If your version of
5468 diff does not support these options, then get the latest version of
5471 The current directory when running this command shall be the parent
5472 directory of the U-Boot source tree (i. e. please make sure that
5473 your patch includes sufficient directory information for the
5476 We prefer patches as plain text. MIME attachments are discouraged,
5477 and compressed attachments must not be used.
5479 * If one logical set of modifications affects or creates several
5480 files, all these changes shall be submitted in a SINGLE patch file.
5482 * Changesets that contain different, unrelated modifications shall be
5483 submitted as SEPARATE patches, one patch per changeset.
5488 * Before sending the patch, run the MAKEALL script on your patched
5489 source tree and make sure that no errors or warnings are reported
5490 for any of the boards.
5492 * Keep your modifications to the necessary minimum: A patch
5493 containing several unrelated changes or arbitrary reformats will be
5494 returned with a request to re-formatting / split it.
5496 * If you modify existing code, make sure that your new code does not
5497 add to the memory footprint of the code ;-) Small is beautiful!
5498 When adding new features, these should compile conditionally only
5499 (using #ifdef), and the resulting code with the new feature
5500 disabled must not need more memory than the old code without your
5503 * Remember that there is a size limit of 100 kB per message on the
5504 u-boot mailing list. Bigger patches will be moderated. If they are
5505 reasonable and not too big, they will be acknowledged. But patches
5506 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob