2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 CONFIG_ARM_ERRATA_716044
489 CONFIG_ARM_ERRATA_742230
490 CONFIG_ARM_ERRATA_743622
491 CONFIG_ARM_ERRATA_751472
493 If set, the workarounds for these ARM errata are applied early
494 during U-Boot startup. Note that these options force the
495 workarounds to be applied; no CPU-type/version detection
496 exists, unlike the similar options in the Linux kernel. Do not
497 set these options unless they apply!
499 - Linux Kernel Interface:
502 U-Boot stores all clock information in Hz
503 internally. For binary compatibility with older Linux
504 kernels (which expect the clocks passed in the
505 bd_info data to be in MHz) the environment variable
506 "clocks_in_mhz" can be defined so that U-Boot
507 converts clock data to MHZ before passing it to the
509 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
510 "clocks_in_mhz=1" is automatically included in the
513 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
515 When transferring memsize parameter to linux, some versions
516 expect it to be in bytes, others in MB.
517 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
521 New kernel versions are expecting firmware settings to be
522 passed using flattened device trees (based on open firmware
526 * New libfdt-based support
527 * Adds the "fdt" command
528 * The bootm command automatically updates the fdt
530 OF_CPU - The proper name of the cpus node (only required for
531 MPC512X and MPC5xxx based boards).
532 OF_SOC - The proper name of the soc node (only required for
533 MPC512X and MPC5xxx based boards).
534 OF_TBCLK - The timebase frequency.
535 OF_STDOUT_PATH - The path to the console device
537 boards with QUICC Engines require OF_QE to set UCC MAC
540 CONFIG_OF_BOARD_SETUP
542 Board code has addition modification that it wants to make
543 to the flat device tree before handing it off to the kernel
547 This define fills in the correct boot CPU in the boot
548 param header, the default value is zero if undefined.
552 U-Boot can detect if an IDE device is present or not.
553 If not, and this new config option is activated, U-Boot
554 removes the ATA node from the DTS before booting Linux,
555 so the Linux IDE driver does not probe the device and
556 crash. This is needed for buggy hardware (uc101) where
557 no pull down resistor is connected to the signal IDE5V_DD7.
559 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
561 This setting is mandatory for all boards that have only one
562 machine type and must be used to specify the machine type
563 number as it appears in the ARM machine registry
564 (see http://www.arm.linux.org.uk/developer/machines/).
565 Only boards that have multiple machine types supported
566 in a single configuration file and the machine type is
567 runtime discoverable, do not have to use this setting.
569 - vxWorks boot parameters:
571 bootvx constructs a valid bootline using the following
572 environments variables: bootfile, ipaddr, serverip, hostname.
573 It loads the vxWorks image pointed bootfile.
575 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
576 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
577 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
578 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
580 CONFIG_SYS_VXWORKS_ADD_PARAMS
582 Add it at the end of the bootline. E.g "u=username pw=secret"
584 Note: If a "bootargs" environment is defined, it will overwride
585 the defaults discussed just above.
587 - Cache Configuration:
588 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
589 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
590 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
592 - Cache Configuration for ARM:
593 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
595 CONFIG_SYS_PL310_BASE - Physical base address of PL310
596 controller register space
601 Define this if you want support for Amba PrimeCell PL010 UARTs.
605 Define this if you want support for Amba PrimeCell PL011 UARTs.
609 If you have Amba PrimeCell PL011 UARTs, set this variable to
610 the clock speed of the UARTs.
614 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
615 define this to a list of base addresses for each (supported)
616 port. See e.g. include/configs/versatile.h
618 CONFIG_PL011_SERIAL_RLCR
620 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
621 have separate receive and transmit line control registers. Set
622 this variable to initialize the extra register.
624 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
626 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
627 boot loader that has already initialized the UART. Define this
628 variable to flush the UART at init time.
630 CONFIG_SYS_NS16550_BROKEN_TEMT
632 16550 UART set the Transmitter Empty (TEMT) Bit when all output
633 has finished and the transmitter is totally empty. U-Boot waits
634 for this bit to be set to initialize the serial console. On some
635 broken platforms this bit is not set in SPL making U-Boot to
636 hang while waiting for TEMT. Define this option to avoid it.
640 Depending on board, define exactly one serial port
641 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
642 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
643 console by defining CONFIG_8xx_CONS_NONE
645 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
646 port routines must be defined elsewhere
647 (i.e. serial_init(), serial_getc(), ...)
650 Enables console device for a color framebuffer. Needs following
651 defines (cf. smiLynxEM, i8042)
652 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
654 VIDEO_HW_RECTFILL graphic chip supports
657 VIDEO_HW_BITBLT graphic chip supports
658 bit-blit (cf. smiLynxEM)
659 VIDEO_VISIBLE_COLS visible pixel columns
661 VIDEO_VISIBLE_ROWS visible pixel rows
662 VIDEO_PIXEL_SIZE bytes per pixel
663 VIDEO_DATA_FORMAT graphic data format
664 (0-5, cf. cfb_console.c)
665 VIDEO_FB_ADRS framebuffer address
666 VIDEO_KBD_INIT_FCT keyboard int fct
667 (i.e. i8042_kbd_init())
668 VIDEO_TSTC_FCT test char fct
670 VIDEO_GETC_FCT get char fct
672 CONFIG_CONSOLE_CURSOR cursor drawing on/off
673 (requires blink timer
675 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
676 CONFIG_CONSOLE_TIME display time/date info in
678 (requires CONFIG_CMD_DATE)
679 CONFIG_VIDEO_LOGO display Linux logo in
681 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
682 linux_logo.h for logo.
683 Requires CONFIG_VIDEO_LOGO
684 CONFIG_CONSOLE_EXTRA_INFO
685 additional board info beside
688 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
689 a limited number of ANSI escape sequences (cursor control,
690 erase functions and limited graphics rendition control).
692 When CONFIG_CFB_CONSOLE is defined, video console is
693 default i/o. Serial console can be forced with
694 environment 'console=serial'.
696 When CONFIG_SILENT_CONSOLE is defined, all console
697 messages (by U-Boot and Linux!) can be silenced with
698 the "silent" environment variable. See
699 doc/README.silent for more information.
702 CONFIG_BAUDRATE - in bps
703 Select one of the baudrates listed in
704 CONFIG_SYS_BAUDRATE_TABLE, see below.
705 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
707 - Console Rx buffer length
708 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
709 the maximum receive buffer length for the SMC.
710 This option is actual only for 82xx and 8xx possible.
711 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
712 must be defined, to setup the maximum idle timeout for
715 - Pre-Console Buffer:
716 Prior to the console being initialised (i.e. serial UART
717 initialised etc) all console output is silently discarded.
718 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
719 buffer any console messages prior to the console being
720 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
721 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
722 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
723 bytes are output before the console is initialised, the
724 earlier bytes are discarded.
726 'Sane' compilers will generate smaller code if
727 CONFIG_PRE_CON_BUF_SZ is a power of 2
729 - Safe printf() functions
730 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
731 the printf() functions. These are defined in
732 include/vsprintf.h and include snprintf(), vsnprintf() and
733 so on. Code size increase is approximately 300-500 bytes.
734 If this option is not given then these functions will
735 silently discard their buffer size argument - this means
736 you are not getting any overflow checking in this case.
738 - Boot Delay: CONFIG_BOOTDELAY - in seconds
739 Delay before automatically booting the default image;
740 set to -1 to disable autoboot.
741 set to -2 to autoboot with no delay and not check for abort
742 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
744 See doc/README.autoboot for these options that
745 work with CONFIG_BOOTDELAY. None are required.
746 CONFIG_BOOT_RETRY_TIME
747 CONFIG_BOOT_RETRY_MIN
748 CONFIG_AUTOBOOT_KEYED
749 CONFIG_AUTOBOOT_PROMPT
750 CONFIG_AUTOBOOT_DELAY_STR
751 CONFIG_AUTOBOOT_STOP_STR
752 CONFIG_AUTOBOOT_DELAY_STR2
753 CONFIG_AUTOBOOT_STOP_STR2
754 CONFIG_ZERO_BOOTDELAY_CHECK
755 CONFIG_RESET_TO_RETRY
759 Only needed when CONFIG_BOOTDELAY is enabled;
760 define a command string that is automatically executed
761 when no character is read on the console interface
762 within "Boot Delay" after reset.
765 This can be used to pass arguments to the bootm
766 command. The value of CONFIG_BOOTARGS goes into the
767 environment value "bootargs".
769 CONFIG_RAMBOOT and CONFIG_NFSBOOT
770 The value of these goes into the environment as
771 "ramboot" and "nfsboot" respectively, and can be used
772 as a convenience, when switching between booting from
778 When this option is #defined, the existence of the
779 environment variable "preboot" will be checked
780 immediately before starting the CONFIG_BOOTDELAY
781 countdown and/or running the auto-boot command resp.
782 entering interactive mode.
784 This feature is especially useful when "preboot" is
785 automatically generated or modified. For an example
786 see the LWMON board specific code: here "preboot" is
787 modified when the user holds down a certain
788 combination of keys on the (special) keyboard when
791 - Serial Download Echo Mode:
793 If defined to 1, all characters received during a
794 serial download (using the "loads" command) are
795 echoed back. This might be needed by some terminal
796 emulations (like "cu"), but may as well just take
797 time on others. This setting #define's the initial
798 value of the "loads_echo" environment variable.
800 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
802 Select one of the baudrates listed in
803 CONFIG_SYS_BAUDRATE_TABLE, see below.
806 Monitor commands can be included or excluded
807 from the build by using the #include files
808 <config_cmd_all.h> and #undef'ing unwanted
809 commands, or using <config_cmd_default.h>
810 and augmenting with additional #define's
813 The default command configuration includes all commands
814 except those marked below with a "*".
816 CONFIG_CMD_ASKENV * ask for env variable
817 CONFIG_CMD_BDI bdinfo
818 CONFIG_CMD_BEDBUG * Include BedBug Debugger
819 CONFIG_CMD_BMP * BMP support
820 CONFIG_CMD_BSP * Board specific commands
821 CONFIG_CMD_BOOTD bootd
822 CONFIG_CMD_CACHE * icache, dcache
823 CONFIG_CMD_CONSOLE coninfo
824 CONFIG_CMD_CRC32 * crc32
825 CONFIG_CMD_DATE * support for RTC, date/time...
826 CONFIG_CMD_DHCP * DHCP support
827 CONFIG_CMD_DIAG * Diagnostics
828 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
829 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
830 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
831 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
832 CONFIG_CMD_DTT * Digital Therm and Thermostat
833 CONFIG_CMD_ECHO echo arguments
834 CONFIG_CMD_EDITENV edit env variable
835 CONFIG_CMD_EEPROM * EEPROM read/write support
836 CONFIG_CMD_ELF * bootelf, bootvx
837 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
838 CONFIG_CMD_ENV_FLAGS * display details about env flags
839 CONFIG_CMD_EXPORTENV * export the environment
840 CONFIG_CMD_EXT2 * ext2 command support
841 CONFIG_CMD_EXT4 * ext4 command support
842 CONFIG_CMD_SAVEENV saveenv
843 CONFIG_CMD_FDC * Floppy Disk Support
844 CONFIG_CMD_FAT * FAT command support
845 CONFIG_CMD_FDOS * Dos diskette Support
846 CONFIG_CMD_FLASH flinfo, erase, protect
847 CONFIG_CMD_FPGA FPGA device initialization support
848 CONFIG_CMD_GETTIME * Get time since boot
849 CONFIG_CMD_GO * the 'go' command (exec code)
850 CONFIG_CMD_GREPENV * search environment
851 CONFIG_CMD_HASH * calculate hash / digest
852 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
853 CONFIG_CMD_I2C * I2C serial bus support
854 CONFIG_CMD_IDE * IDE harddisk support
855 CONFIG_CMD_IMI iminfo
856 CONFIG_CMD_IMLS List all images found in NOR flash
857 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
858 CONFIG_CMD_IMMAP * IMMR dump support
859 CONFIG_CMD_IMPORTENV * import an environment
860 CONFIG_CMD_INI * import data from an ini file into the env
861 CONFIG_CMD_IRQ * irqinfo
862 CONFIG_CMD_ITEST Integer/string test of 2 values
863 CONFIG_CMD_JFFS2 * JFFS2 Support
864 CONFIG_CMD_KGDB * kgdb
865 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
866 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
868 CONFIG_CMD_LOADB loadb
869 CONFIG_CMD_LOADS loads
870 CONFIG_CMD_MD5SUM print md5 message digest
871 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
872 CONFIG_CMD_MEMINFO * Display detailed memory information
873 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
875 CONFIG_CMD_MEMTEST mtest
876 CONFIG_CMD_MISC Misc functions like sleep etc
877 CONFIG_CMD_MMC * MMC memory mapped support
878 CONFIG_CMD_MII * MII utility commands
879 CONFIG_CMD_MTDPARTS * MTD partition support
880 CONFIG_CMD_NAND * NAND support
881 CONFIG_CMD_NET bootp, tftpboot, rarpboot
882 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
883 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
884 CONFIG_CMD_PCI * pciinfo
885 CONFIG_CMD_PCMCIA * PCMCIA support
886 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
888 CONFIG_CMD_PORTIO * Port I/O
889 CONFIG_CMD_READ * Read raw data from partition
890 CONFIG_CMD_REGINFO * Register dump
891 CONFIG_CMD_RUN run command in env variable
892 CONFIG_CMD_SANDBOX * sb command to access sandbox features
893 CONFIG_CMD_SAVES * save S record dump
894 CONFIG_CMD_SCSI * SCSI Support
895 CONFIG_CMD_SDRAM * print SDRAM configuration information
896 (requires CONFIG_CMD_I2C)
897 CONFIG_CMD_SETGETDCR Support for DCR Register access
899 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
900 CONFIG_CMD_SHA1SUM print sha1 memory digest
901 (requires CONFIG_CMD_MEMORY)
902 CONFIG_CMD_SOURCE "source" command Support
903 CONFIG_CMD_SPI * SPI serial bus support
904 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
905 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
906 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
907 CONFIG_CMD_TIMER * access to the system tick timer
908 CONFIG_CMD_USB * USB support
909 CONFIG_CMD_CDP * Cisco Discover Protocol support
910 CONFIG_CMD_MFSL * Microblaze FSL support
913 EXAMPLE: If you want all functions except of network
914 support you can write:
916 #include "config_cmd_all.h"
917 #undef CONFIG_CMD_NET
920 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
922 Note: Don't enable the "icache" and "dcache" commands
923 (configuration option CONFIG_CMD_CACHE) unless you know
924 what you (and your U-Boot users) are doing. Data
925 cache cannot be enabled on systems like the 8xx or
926 8260 (where accesses to the IMMR region must be
927 uncached), and it cannot be disabled on all other
928 systems where we (mis-) use the data cache to hold an
929 initial stack and some data.
932 XXX - this list needs to get updated!
936 If this variable is defined, U-Boot will use a device tree
937 to configure its devices, instead of relying on statically
938 compiled #defines in the board file. This option is
939 experimental and only available on a few boards. The device
940 tree is available in the global data as gd->fdt_blob.
942 U-Boot needs to get its device tree from somewhere. This can
943 be done using one of the two options below:
946 If this variable is defined, U-Boot will embed a device tree
947 binary in its image. This device tree file should be in the
948 board directory and called <soc>-<board>.dts. The binary file
949 is then picked up in board_init_f() and made available through
950 the global data structure as gd->blob.
953 If this variable is defined, U-Boot will build a device tree
954 binary. It will be called u-boot.dtb. Architecture-specific
955 code will locate it at run-time. Generally this works by:
957 cat u-boot.bin u-boot.dtb >image.bin
959 and in fact, U-Boot does this for you, creating a file called
960 u-boot-dtb.bin which is useful in the common case. You can
961 still use the individual files if you need something more
966 If this variable is defined, it enables watchdog
967 support for the SoC. There must be support in the SoC
968 specific code for a watchdog. For the 8xx and 8260
969 CPUs, the SIU Watchdog feature is enabled in the SYPCR
970 register. When supported for a specific SoC is
971 available, then no further board specific code should
975 When using a watchdog circuitry external to the used
976 SoC, then define this variable and provide board
977 specific code for the "hw_watchdog_reset" function.
980 CONFIG_VERSION_VARIABLE
981 If this variable is defined, an environment variable
982 named "ver" is created by U-Boot showing the U-Boot
983 version as printed by the "version" command.
984 Any change to this variable will be reverted at the
989 When CONFIG_CMD_DATE is selected, the type of the RTC
990 has to be selected, too. Define exactly one of the
993 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
994 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
995 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
996 CONFIG_RTC_MC146818 - use MC146818 RTC
997 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
998 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
999 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1000 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1001 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1002 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1003 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1004 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1007 Note that if the RTC uses I2C, then the I2C interface
1008 must also be configured. See I2C Support, below.
1011 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1012 CONFIG_PCA953X_INFO - enable pca953x info command
1014 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1015 chip-ngpio pairs that tell the PCA953X driver the number of
1016 pins supported by a particular chip.
1018 Note that if the GPIO device uses I2C, then the I2C interface
1019 must also be configured. See I2C Support, below.
1021 - Timestamp Support:
1023 When CONFIG_TIMESTAMP is selected, the timestamp
1024 (date and time) of an image is printed by image
1025 commands like bootm or iminfo. This option is
1026 automatically enabled when you select CONFIG_CMD_DATE .
1028 - Partition Labels (disklabels) Supported:
1029 Zero or more of the following:
1030 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1031 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1032 Intel architecture, USB sticks, etc.
1033 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1034 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1035 bootloader. Note 2TB partition limit; see
1037 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1039 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1040 CONFIG_CMD_SCSI) you must configure support for at
1041 least one non-MTD partition type as well.
1044 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1045 board configurations files but used nowhere!
1047 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1048 be performed by calling the function
1049 ide_set_reset(int reset)
1050 which has to be defined in a board specific file
1055 Set this to enable ATAPI support.
1060 Set this to enable support for disks larger than 137GB
1061 Also look at CONFIG_SYS_64BIT_LBA.
1062 Whithout these , LBA48 support uses 32bit variables and will 'only'
1063 support disks up to 2.1TB.
1065 CONFIG_SYS_64BIT_LBA:
1066 When enabled, makes the IDE subsystem use 64bit sector addresses.
1070 At the moment only there is only support for the
1071 SYM53C8XX SCSI controller; define
1072 CONFIG_SCSI_SYM53C8XX to enable it.
1074 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1075 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1076 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1077 maximum numbers of LUNs, SCSI ID's and target
1079 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1081 The environment variable 'scsidevs' is set to the number of
1082 SCSI devices found during the last scan.
1084 - NETWORK Support (PCI):
1086 Support for Intel 8254x/8257x gigabit chips.
1089 Utility code for direct access to the SPI bus on Intel 8257x.
1090 This does not do anything useful unless you set at least one
1091 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1093 CONFIG_E1000_SPI_GENERIC
1094 Allow generic access to the SPI bus on the Intel 8257x, for
1095 example with the "sspi" command.
1098 Management command for E1000 devices. When used on devices
1099 with SPI support you can reprogram the EEPROM from U-Boot.
1101 CONFIG_E1000_FALLBACK_MAC
1102 default MAC for empty EEPROM after production.
1105 Support for Intel 82557/82559/82559ER chips.
1106 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1107 write routine for first time initialisation.
1110 Support for Digital 2114x chips.
1111 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1112 modem chip initialisation (KS8761/QS6611).
1115 Support for National dp83815 chips.
1118 Support for National dp8382[01] gigabit chips.
1120 - NETWORK Support (other):
1122 CONFIG_DRIVER_AT91EMAC
1123 Support for AT91RM9200 EMAC.
1126 Define this to use reduced MII inteface
1128 CONFIG_DRIVER_AT91EMAC_QUIET
1129 If this defined, the driver is quiet.
1130 The driver doen't show link status messages.
1132 CONFIG_CALXEDA_XGMAC
1133 Support for the Calxeda XGMAC device
1136 Support for SMSC's LAN91C96 chips.
1138 CONFIG_LAN91C96_BASE
1139 Define this to hold the physical address
1140 of the LAN91C96's I/O space
1142 CONFIG_LAN91C96_USE_32_BIT
1143 Define this to enable 32 bit addressing
1146 Support for SMSC's LAN91C111 chip
1148 CONFIG_SMC91111_BASE
1149 Define this to hold the physical address
1150 of the device (I/O space)
1152 CONFIG_SMC_USE_32_BIT
1153 Define this if data bus is 32 bits
1155 CONFIG_SMC_USE_IOFUNCS
1156 Define this to use i/o functions instead of macros
1157 (some hardware wont work with macros)
1159 CONFIG_DRIVER_TI_EMAC
1160 Support for davinci emac
1162 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1163 Define this if you have more then 3 PHYs.
1166 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1168 CONFIG_FTGMAC100_EGIGA
1169 Define this to use GE link update with gigabit PHY.
1170 Define this if FTGMAC100 is connected to gigabit PHY.
1171 If your system has 10/100 PHY only, it might not occur
1172 wrong behavior. Because PHY usually return timeout or
1173 useless data when polling gigabit status and gigabit
1174 control registers. This behavior won't affect the
1175 correctnessof 10/100 link speed update.
1178 Support for SMSC's LAN911x and LAN921x chips
1181 Define this to hold the physical address
1182 of the device (I/O space)
1184 CONFIG_SMC911X_32_BIT
1185 Define this if data bus is 32 bits
1187 CONFIG_SMC911X_16_BIT
1188 Define this if data bus is 16 bits. If your processor
1189 automatically converts one 32 bit word to two 16 bit
1190 words you may also try CONFIG_SMC911X_32_BIT.
1193 Support for Renesas on-chip Ethernet controller
1195 CONFIG_SH_ETHER_USE_PORT
1196 Define the number of ports to be used
1198 CONFIG_SH_ETHER_PHY_ADDR
1199 Define the ETH PHY's address
1201 CONFIG_SH_ETHER_CACHE_WRITEBACK
1202 If this option is set, the driver enables cache flush.
1205 CONFIG_GENERIC_LPC_TPM
1206 Support for generic parallel port TPM devices. Only one device
1207 per system is supported at this time.
1209 CONFIG_TPM_TIS_BASE_ADDRESS
1210 Base address where the generic TPM device is mapped
1211 to. Contemporary x86 systems usually map it at
1215 At the moment only the UHCI host controller is
1216 supported (PIP405, MIP405, MPC5200); define
1217 CONFIG_USB_UHCI to enable it.
1218 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1219 and define CONFIG_USB_STORAGE to enable the USB
1222 Supported are USB Keyboards and USB Floppy drives
1224 MPC5200 USB requires additional defines:
1226 for 528 MHz Clock: 0x0001bbbb
1230 for differential drivers: 0x00001000
1231 for single ended drivers: 0x00005000
1232 for differential drivers on PSC3: 0x00000100
1233 for single ended drivers on PSC3: 0x00004100
1234 CONFIG_SYS_USB_EVENT_POLL
1235 May be defined to allow interrupt polling
1236 instead of using asynchronous interrupts
1238 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1239 txfilltuning field in the EHCI controller on reset.
1242 Define the below if you wish to use the USB console.
1243 Once firmware is rebuilt from a serial console issue the
1244 command "setenv stdin usbtty; setenv stdout usbtty" and
1245 attach your USB cable. The Unix command "dmesg" should print
1246 it has found a new device. The environment variable usbtty
1247 can be set to gserial or cdc_acm to enable your device to
1248 appear to a USB host as a Linux gserial device or a
1249 Common Device Class Abstract Control Model serial device.
1250 If you select usbtty = gserial you should be able to enumerate
1252 # modprobe usbserial vendor=0xVendorID product=0xProductID
1253 else if using cdc_acm, simply setting the environment
1254 variable usbtty to be cdc_acm should suffice. The following
1255 might be defined in YourBoardName.h
1258 Define this to build a UDC device
1261 Define this to have a tty type of device available to
1262 talk to the UDC device
1265 Define this to enable the high speed support for usb
1266 device and usbtty. If this feature is enabled, a routine
1267 int is_usbd_high_speed(void)
1268 also needs to be defined by the driver to dynamically poll
1269 whether the enumeration has succeded at high speed or full
1272 CONFIG_SYS_CONSOLE_IS_IN_ENV
1273 Define this if you want stdin, stdout &/or stderr to
1277 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1278 Derive USB clock from external clock "blah"
1279 - CONFIG_SYS_USB_EXTC_CLK 0x02
1281 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1282 Derive USB clock from brgclk
1283 - CONFIG_SYS_USB_BRG_CLK 0x04
1285 If you have a USB-IF assigned VendorID then you may wish to
1286 define your own vendor specific values either in BoardName.h
1287 or directly in usbd_vendor_info.h. If you don't define
1288 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1289 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1290 should pretend to be a Linux device to it's target host.
1292 CONFIG_USBD_MANUFACTURER
1293 Define this string as the name of your company for
1294 - CONFIG_USBD_MANUFACTURER "my company"
1296 CONFIG_USBD_PRODUCT_NAME
1297 Define this string as the name of your product
1298 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1300 CONFIG_USBD_VENDORID
1301 Define this as your assigned Vendor ID from the USB
1302 Implementors Forum. This *must* be a genuine Vendor ID
1303 to avoid polluting the USB namespace.
1304 - CONFIG_USBD_VENDORID 0xFFFF
1306 CONFIG_USBD_PRODUCTID
1307 Define this as the unique Product ID
1309 - CONFIG_USBD_PRODUCTID 0xFFFF
1311 - ULPI Layer Support:
1312 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1313 the generic ULPI layer. The generic layer accesses the ULPI PHY
1314 via the platform viewport, so you need both the genric layer and
1315 the viewport enabled. Currently only Chipidea/ARC based
1316 viewport is supported.
1317 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1318 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1319 If your ULPI phy needs a different reference clock than the
1320 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1321 the appropriate value in Hz.
1324 The MMC controller on the Intel PXA is supported. To
1325 enable this define CONFIG_MMC. The MMC can be
1326 accessed from the boot prompt by mapping the device
1327 to physical memory similar to flash. Command line is
1328 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1329 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1332 Support for Renesas on-chip MMCIF controller
1334 CONFIG_SH_MMCIF_ADDR
1335 Define the base address of MMCIF registers
1338 Define the clock frequency for MMCIF
1340 - Journaling Flash filesystem support:
1341 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1342 CONFIG_JFFS2_NAND_DEV
1343 Define these for a default partition on a NAND device
1345 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1346 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1347 Define these for a default partition on a NOR device
1349 CONFIG_SYS_JFFS_CUSTOM_PART
1350 Define this to create an own partition. You have to provide a
1351 function struct part_info* jffs2_part_info(int part_num)
1353 If you define only one JFFS2 partition you may also want to
1354 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1355 to disable the command chpart. This is the default when you
1356 have not defined a custom partition
1358 - FAT(File Allocation Table) filesystem write function support:
1361 Define this to enable support for saving memory data as a
1362 file in FAT formatted partition.
1364 This will also enable the command "fatwrite" enabling the
1365 user to write files to FAT.
1367 CBFS (Coreboot Filesystem) support
1370 Define this to enable support for reading from a Coreboot
1371 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1377 Define this to enable standard (PC-Style) keyboard
1381 Standard PC keyboard driver with US (is default) and
1382 GERMAN key layout (switch via environment 'keymap=de') support.
1383 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1384 for cfb_console. Supports cursor blinking.
1389 Define this to enable video support (for output to
1392 CONFIG_VIDEO_CT69000
1394 Enable Chips & Technologies 69000 Video chip
1396 CONFIG_VIDEO_SMI_LYNXEM
1397 Enable Silicon Motion SMI 712/710/810 Video chip. The
1398 video output is selected via environment 'videoout'
1399 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1402 For the CT69000 and SMI_LYNXEM drivers, videomode is
1403 selected via environment 'videomode'. Two different ways
1405 - "videomode=num" 'num' is a standard LiLo mode numbers.
1406 Following standard modes are supported (* is default):
1408 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1409 -------------+---------------------------------------------
1410 8 bits | 0x301* 0x303 0x305 0x161 0x307
1411 15 bits | 0x310 0x313 0x316 0x162 0x319
1412 16 bits | 0x311 0x314 0x317 0x163 0x31A
1413 24 bits | 0x312 0x315 0x318 ? 0x31B
1414 -------------+---------------------------------------------
1415 (i.e. setenv videomode 317; saveenv; reset;)
1417 - "videomode=bootargs" all the video parameters are parsed
1418 from the bootargs. (See drivers/video/videomodes.c)
1421 CONFIG_VIDEO_SED13806
1422 Enable Epson SED13806 driver. This driver supports 8bpp
1423 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1424 or CONFIG_VIDEO_SED13806_16BPP
1427 Enable the Freescale DIU video driver. Reference boards for
1428 SOCs that have a DIU should define this macro to enable DIU
1429 support, and should also define these other macros:
1435 CONFIG_VIDEO_SW_CURSOR
1436 CONFIG_VGA_AS_SINGLE_DEVICE
1438 CONFIG_VIDEO_BMP_LOGO
1440 The DIU driver will look for the 'video-mode' environment
1441 variable, and if defined, enable the DIU as a console during
1442 boot. See the documentation file README.video for a
1443 description of this variable.
1447 Enable the VGA video / BIOS for x86. The alternative if you
1448 are using coreboot is to use the coreboot frame buffer
1455 Define this to enable a custom keyboard support.
1456 This simply calls drv_keyboard_init() which must be
1457 defined in your board-specific files.
1458 The only board using this so far is RBC823.
1460 - LCD Support: CONFIG_LCD
1462 Define this to enable LCD support (for output to LCD
1463 display); also select one of the supported displays
1464 by defining one of these:
1468 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1470 CONFIG_NEC_NL6448AC33:
1472 NEC NL6448AC33-18. Active, color, single scan.
1474 CONFIG_NEC_NL6448BC20
1476 NEC NL6448BC20-08. 6.5", 640x480.
1477 Active, color, single scan.
1479 CONFIG_NEC_NL6448BC33_54
1481 NEC NL6448BC33-54. 10.4", 640x480.
1482 Active, color, single scan.
1486 Sharp 320x240. Active, color, single scan.
1487 It isn't 16x9, and I am not sure what it is.
1489 CONFIG_SHARP_LQ64D341
1491 Sharp LQ64D341 display, 640x480.
1492 Active, color, single scan.
1496 HLD1045 display, 640x480.
1497 Active, color, single scan.
1501 Optrex CBL50840-2 NF-FW 99 22 M5
1503 Hitachi LMG6912RPFC-00T
1507 320x240. Black & white.
1509 Normally display is black on white background; define
1510 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1512 CONFIG_LCD_ALIGNMENT
1514 Normally the LCD is page-aligned (tyically 4KB). If this is
1515 defined then the LCD will be aligned to this value instead.
1516 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1517 here, since it is cheaper to change data cache settings on
1518 a per-section basis.
1520 CONFIG_CONSOLE_SCROLL_LINES
1522 When the console need to be scrolled, this is the number of
1523 lines to scroll by. It defaults to 1. Increasing this makes
1524 the console jump but can help speed up operation when scrolling
1529 Support drawing of RLE8-compressed bitmaps on the LCD.
1533 Enables an 'i2c edid' command which can read EDID
1534 information over I2C from an attached LCD display.
1536 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1538 If this option is set, the environment is checked for
1539 a variable "splashimage". If found, the usual display
1540 of logo, copyright and system information on the LCD
1541 is suppressed and the BMP image at the address
1542 specified in "splashimage" is loaded instead. The
1543 console is redirected to the "nulldev", too. This
1544 allows for a "silent" boot where a splash screen is
1545 loaded very quickly after power-on.
1547 CONFIG_SPLASHIMAGE_GUARD
1549 If this option is set, then U-Boot will prevent the environment
1550 variable "splashimage" from being set to a problematic address
1551 (see README.displaying-bmps and README.arm-unaligned-accesses).
1552 This option is useful for targets where, due to alignment
1553 restrictions, an improperly aligned BMP image will cause a data
1554 abort. If you think you will not have problems with unaligned
1555 accesses (for example because your toolchain prevents them)
1556 there is no need to set this option.
1558 CONFIG_SPLASH_SCREEN_ALIGN
1560 If this option is set the splash image can be freely positioned
1561 on the screen. Environment variable "splashpos" specifies the
1562 position as "x,y". If a positive number is given it is used as
1563 number of pixel from left/top. If a negative number is given it
1564 is used as number of pixel from right/bottom. You can also
1565 specify 'm' for centering the image.
1568 setenv splashpos m,m
1569 => image at center of screen
1571 setenv splashpos 30,20
1572 => image at x = 30 and y = 20
1574 setenv splashpos -10,m
1575 => vertically centered image
1576 at x = dspWidth - bmpWidth - 9
1578 CONFIG_SPLASH_SCREEN_PREPARE
1580 If this option is set then the board_splash_screen_prepare()
1581 function, which must be defined in your code, is called as part
1582 of the splash screen display sequence. It gives the board an
1583 opportunity to prepare the splash image data before it is
1584 processed and sent to the frame buffer by U-Boot.
1586 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1588 If this option is set, additionally to standard BMP
1589 images, gzipped BMP images can be displayed via the
1590 splashscreen support or the bmp command.
1592 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1594 If this option is set, 8-bit RLE compressed BMP images
1595 can be displayed via the splashscreen support or the
1598 - Do compresssing for memory range:
1601 If this option is set, it would use zlib deflate method
1602 to compress the specified memory at its best effort.
1604 - Compression support:
1607 If this option is set, support for bzip2 compressed
1608 images is included. If not, only uncompressed and gzip
1609 compressed images are supported.
1611 NOTE: the bzip2 algorithm requires a lot of RAM, so
1612 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1617 If this option is set, support for lzma compressed
1620 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1621 requires an amount of dynamic memory that is given by the
1624 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1626 Where lc and lp stand for, respectively, Literal context bits
1627 and Literal pos bits.
1629 This value is upper-bounded by 14MB in the worst case. Anyway,
1630 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1631 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1632 a very small buffer.
1634 Use the lzmainfo tool to determinate the lc and lp values and
1635 then calculate the amount of needed dynamic memory (ensuring
1636 the appropriate CONFIG_SYS_MALLOC_LEN value).
1641 The address of PHY on MII bus.
1643 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1645 The clock frequency of the MII bus
1649 If this option is set, support for speed/duplex
1650 detection of gigabit PHY is included.
1652 CONFIG_PHY_RESET_DELAY
1654 Some PHY like Intel LXT971A need extra delay after
1655 reset before any MII register access is possible.
1656 For such PHY, set this option to the usec delay
1657 required. (minimum 300usec for LXT971A)
1659 CONFIG_PHY_CMD_DELAY (ppc4xx)
1661 Some PHY like Intel LXT971A need extra delay after
1662 command issued before MII status register can be read
1672 Define a default value for Ethernet address to use
1673 for the respective Ethernet interface, in case this
1674 is not determined automatically.
1679 Define a default value for the IP address to use for
1680 the default Ethernet interface, in case this is not
1681 determined through e.g. bootp.
1682 (Environment variable "ipaddr")
1684 - Server IP address:
1687 Defines a default value for the IP address of a TFTP
1688 server to contact when using the "tftboot" command.
1689 (Environment variable "serverip")
1691 CONFIG_KEEP_SERVERADDR
1693 Keeps the server's MAC address, in the env 'serveraddr'
1694 for passing to bootargs (like Linux's netconsole option)
1696 - Gateway IP address:
1699 Defines a default value for the IP address of the
1700 default router where packets to other networks are
1702 (Environment variable "gatewayip")
1707 Defines a default value for the subnet mask (or
1708 routing prefix) which is used to determine if an IP
1709 address belongs to the local subnet or needs to be
1710 forwarded through a router.
1711 (Environment variable "netmask")
1713 - Multicast TFTP Mode:
1716 Defines whether you want to support multicast TFTP as per
1717 rfc-2090; for example to work with atftp. Lets lots of targets
1718 tftp down the same boot image concurrently. Note: the Ethernet
1719 driver in use must provide a function: mcast() to join/leave a
1722 - BOOTP Recovery Mode:
1723 CONFIG_BOOTP_RANDOM_DELAY
1725 If you have many targets in a network that try to
1726 boot using BOOTP, you may want to avoid that all
1727 systems send out BOOTP requests at precisely the same
1728 moment (which would happen for instance at recovery
1729 from a power failure, when all systems will try to
1730 boot, thus flooding the BOOTP server. Defining
1731 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1732 inserted before sending out BOOTP requests. The
1733 following delays are inserted then:
1735 1st BOOTP request: delay 0 ... 1 sec
1736 2nd BOOTP request: delay 0 ... 2 sec
1737 3rd BOOTP request: delay 0 ... 4 sec
1739 BOOTP requests: delay 0 ... 8 sec
1741 - DHCP Advanced Options:
1742 You can fine tune the DHCP functionality by defining
1743 CONFIG_BOOTP_* symbols:
1745 CONFIG_BOOTP_SUBNETMASK
1746 CONFIG_BOOTP_GATEWAY
1747 CONFIG_BOOTP_HOSTNAME
1748 CONFIG_BOOTP_NISDOMAIN
1749 CONFIG_BOOTP_BOOTPATH
1750 CONFIG_BOOTP_BOOTFILESIZE
1753 CONFIG_BOOTP_SEND_HOSTNAME
1754 CONFIG_BOOTP_NTPSERVER
1755 CONFIG_BOOTP_TIMEOFFSET
1756 CONFIG_BOOTP_VENDOREX
1757 CONFIG_BOOTP_MAY_FAIL
1759 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1760 environment variable, not the BOOTP server.
1762 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1763 after the configured retry count, the call will fail
1764 instead of starting over. This can be used to fail over
1765 to Link-local IP address configuration if the DHCP server
1768 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1769 serverip from a DHCP server, it is possible that more
1770 than one DNS serverip is offered to the client.
1771 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1772 serverip will be stored in the additional environment
1773 variable "dnsip2". The first DNS serverip is always
1774 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1777 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1778 to do a dynamic update of a DNS server. To do this, they
1779 need the hostname of the DHCP requester.
1780 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1781 of the "hostname" environment variable is passed as
1782 option 12 to the DHCP server.
1784 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1786 A 32bit value in microseconds for a delay between
1787 receiving a "DHCP Offer" and sending the "DHCP Request".
1788 This fixes a problem with certain DHCP servers that don't
1789 respond 100% of the time to a "DHCP request". E.g. On an
1790 AT91RM9200 processor running at 180MHz, this delay needed
1791 to be *at least* 15,000 usec before a Windows Server 2003
1792 DHCP server would reply 100% of the time. I recommend at
1793 least 50,000 usec to be safe. The alternative is to hope
1794 that one of the retries will be successful but note that
1795 the DHCP timeout and retry process takes a longer than
1798 - Link-local IP address negotiation:
1799 Negotiate with other link-local clients on the local network
1800 for an address that doesn't require explicit configuration.
1801 This is especially useful if a DHCP server cannot be guaranteed
1802 to exist in all environments that the device must operate.
1804 See doc/README.link-local for more information.
1807 CONFIG_CDP_DEVICE_ID
1809 The device id used in CDP trigger frames.
1811 CONFIG_CDP_DEVICE_ID_PREFIX
1813 A two character string which is prefixed to the MAC address
1818 A printf format string which contains the ascii name of
1819 the port. Normally is set to "eth%d" which sets
1820 eth0 for the first Ethernet, eth1 for the second etc.
1822 CONFIG_CDP_CAPABILITIES
1824 A 32bit integer which indicates the device capabilities;
1825 0x00000010 for a normal host which does not forwards.
1829 An ascii string containing the version of the software.
1833 An ascii string containing the name of the platform.
1837 A 32bit integer sent on the trigger.
1839 CONFIG_CDP_POWER_CONSUMPTION
1841 A 16bit integer containing the power consumption of the
1842 device in .1 of milliwatts.
1844 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1846 A byte containing the id of the VLAN.
1848 - Status LED: CONFIG_STATUS_LED
1850 Several configurations allow to display the current
1851 status using a LED. For instance, the LED will blink
1852 fast while running U-Boot code, stop blinking as
1853 soon as a reply to a BOOTP request was received, and
1854 start blinking slow once the Linux kernel is running
1855 (supported by a status LED driver in the Linux
1856 kernel). Defining CONFIG_STATUS_LED enables this
1859 - CAN Support: CONFIG_CAN_DRIVER
1861 Defining CONFIG_CAN_DRIVER enables CAN driver support
1862 on those systems that support this (optional)
1863 feature, like the TQM8xxL modules.
1865 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1867 These enable I2C serial bus commands. Defining either of
1868 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1869 include the appropriate I2C driver for the selected CPU.
1871 This will allow you to use i2c commands at the u-boot
1872 command line (as long as you set CONFIG_CMD_I2C in
1873 CONFIG_COMMANDS) and communicate with i2c based realtime
1874 clock chips. See common/cmd_i2c.c for a description of the
1875 command line interface.
1877 CONFIG_HARD_I2C selects a hardware I2C controller.
1879 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1880 bit-banging) driver instead of CPM or similar hardware
1883 There are several other quantities that must also be
1884 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1886 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1887 to be the frequency (in Hz) at which you wish your i2c bus
1888 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1889 the CPU's i2c node address).
1891 Now, the u-boot i2c code for the mpc8xx
1892 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1893 and so its address should therefore be cleared to 0 (See,
1894 eg, MPC823e User's Manual p.16-473). So, set
1895 CONFIG_SYS_I2C_SLAVE to 0.
1897 CONFIG_SYS_I2C_INIT_MPC5XXX
1899 When a board is reset during an i2c bus transfer
1900 chips might think that the current transfer is still
1901 in progress. Reset the slave devices by sending start
1902 commands until the slave device responds.
1904 That's all that's required for CONFIG_HARD_I2C.
1906 If you use the software i2c interface (CONFIG_SOFT_I2C)
1907 then the following macros need to be defined (examples are
1908 from include/configs/lwmon.h):
1912 (Optional). Any commands necessary to enable the I2C
1913 controller or configure ports.
1915 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1919 (Only for MPC8260 CPU). The I/O port to use (the code
1920 assumes both bits are on the same port). Valid values
1921 are 0..3 for ports A..D.
1925 The code necessary to make the I2C data line active
1926 (driven). If the data line is open collector, this
1929 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1933 The code necessary to make the I2C data line tri-stated
1934 (inactive). If the data line is open collector, this
1937 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1941 Code that returns TRUE if the I2C data line is high,
1944 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1948 If <bit> is TRUE, sets the I2C data line high. If it
1949 is FALSE, it clears it (low).
1951 eg: #define I2C_SDA(bit) \
1952 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1953 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1957 If <bit> is TRUE, sets the I2C clock line high. If it
1958 is FALSE, it clears it (low).
1960 eg: #define I2C_SCL(bit) \
1961 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1962 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1966 This delay is invoked four times per clock cycle so this
1967 controls the rate of data transfer. The data rate thus
1968 is 1 / (I2C_DELAY * 4). Often defined to be something
1971 #define I2C_DELAY udelay(2)
1973 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1975 If your arch supports the generic GPIO framework (asm/gpio.h),
1976 then you may alternatively define the two GPIOs that are to be
1977 used as SCL / SDA. Any of the previous I2C_xxx macros will
1978 have GPIO-based defaults assigned to them as appropriate.
1980 You should define these to the GPIO value as given directly to
1981 the generic GPIO functions.
1983 CONFIG_SYS_I2C_INIT_BOARD
1985 When a board is reset during an i2c bus transfer
1986 chips might think that the current transfer is still
1987 in progress. On some boards it is possible to access
1988 the i2c SCLK line directly, either by using the
1989 processor pin as a GPIO or by having a second pin
1990 connected to the bus. If this option is defined a
1991 custom i2c_init_board() routine in boards/xxx/board.c
1992 is run early in the boot sequence.
1994 CONFIG_SYS_I2C_BOARD_LATE_INIT
1996 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1997 defined a custom i2c_board_late_init() routine in
1998 boards/xxx/board.c is run AFTER the operations in i2c_init()
1999 is completed. This callpoint can be used to unreset i2c bus
2000 using CPU i2c controller register accesses for CPUs whose i2c
2001 controller provide such a method. It is called at the end of
2002 i2c_init() to allow i2c_init operations to setup the i2c bus
2003 controller on the CPU (e.g. setting bus speed & slave address).
2005 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2007 This option enables configuration of bi_iic_fast[] flags
2008 in u-boot bd_info structure based on u-boot environment
2009 variable "i2cfast". (see also i2cfast)
2011 CONFIG_I2C_MULTI_BUS
2013 This option allows the use of multiple I2C buses, each of which
2014 must have a controller. At any point in time, only one bus is
2015 active. To switch to a different bus, use the 'i2c dev' command.
2016 Note that bus numbering is zero-based.
2018 CONFIG_SYS_I2C_NOPROBES
2020 This option specifies a list of I2C devices that will be skipped
2021 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2022 is set, specify a list of bus-device pairs. Otherwise, specify
2023 a 1D array of device addresses
2026 #undef CONFIG_I2C_MULTI_BUS
2027 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2029 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2031 #define CONFIG_I2C_MULTI_BUS
2032 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2034 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2036 CONFIG_SYS_SPD_BUS_NUM
2038 If defined, then this indicates the I2C bus number for DDR SPD.
2039 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2041 CONFIG_SYS_RTC_BUS_NUM
2043 If defined, then this indicates the I2C bus number for the RTC.
2044 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2046 CONFIG_SYS_DTT_BUS_NUM
2048 If defined, then this indicates the I2C bus number for the DTT.
2049 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2051 CONFIG_SYS_I2C_DTT_ADDR:
2053 If defined, specifies the I2C address of the DTT device.
2054 If not defined, then U-Boot uses predefined value for
2055 specified DTT device.
2059 Define this option if you want to use Freescale's I2C driver in
2060 drivers/i2c/fsl_i2c.c.
2064 Define this option if you have I2C devices reached over 1 .. n
2065 I2C Muxes like the pca9544a. This option addes a new I2C
2066 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2067 new I2C Bus to the existing I2C Busses. If you select the
2068 new Bus with "i2c dev", u-bbot sends first the commandos for
2069 the muxes to activate this new "bus".
2071 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2075 Adding a new I2C Bus reached over 2 pca9544a muxes
2076 The First mux with address 70 and channel 6
2077 The Second mux with address 71 and channel 4
2079 => i2c bus pca9544a:70:6:pca9544a:71:4
2081 Use the "i2c bus" command without parameter, to get a list
2082 of I2C Busses with muxes:
2085 Busses reached over muxes:
2087 reached over Mux(es):
2090 reached over Mux(es):
2095 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2096 u-boot first sends the command to the mux@70 to enable
2097 channel 6, and then the command to the mux@71 to enable
2100 After that, you can use the "normal" i2c commands as
2101 usual to communicate with your I2C devices behind
2104 This option is actually implemented for the bitbanging
2105 algorithm in common/soft_i2c.c and for the Hardware I2C
2106 Bus on the MPC8260. But it should be not so difficult
2107 to add this option to other architectures.
2109 CONFIG_SOFT_I2C_READ_REPEATED_START
2111 defining this will force the i2c_read() function in
2112 the soft_i2c driver to perform an I2C repeated start
2113 between writing the address pointer and reading the
2114 data. If this define is omitted the default behaviour
2115 of doing a stop-start sequence will be used. Most I2C
2116 devices can use either method, but some require one or
2119 - SPI Support: CONFIG_SPI
2121 Enables SPI driver (so far only tested with
2122 SPI EEPROM, also an instance works with Crystal A/D and
2123 D/As on the SACSng board)
2127 Enables the driver for SPI controller on SuperH. Currently
2128 only SH7757 is supported.
2132 Enables extended (16-bit) SPI EEPROM addressing.
2133 (symmetrical to CONFIG_I2C_X)
2137 Enables a software (bit-bang) SPI driver rather than
2138 using hardware support. This is a general purpose
2139 driver that only requires three general I/O port pins
2140 (two outputs, one input) to function. If this is
2141 defined, the board configuration must define several
2142 SPI configuration items (port pins to use, etc). For
2143 an example, see include/configs/sacsng.h.
2147 Enables a hardware SPI driver for general-purpose reads
2148 and writes. As with CONFIG_SOFT_SPI, the board configuration
2149 must define a list of chip-select function pointers.
2150 Currently supported on some MPC8xxx processors. For an
2151 example, see include/configs/mpc8349emds.h.
2155 Enables the driver for the SPI controllers on i.MX and MXC
2156 SoCs. Currently i.MX31/35/51 are supported.
2158 - FPGA Support: CONFIG_FPGA
2160 Enables FPGA subsystem.
2162 CONFIG_FPGA_<vendor>
2164 Enables support for specific chip vendors.
2167 CONFIG_FPGA_<family>
2169 Enables support for FPGA family.
2170 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2174 Specify the number of FPGA devices to support.
2176 CONFIG_SYS_FPGA_PROG_FEEDBACK
2178 Enable printing of hash marks during FPGA configuration.
2180 CONFIG_SYS_FPGA_CHECK_BUSY
2182 Enable checks on FPGA configuration interface busy
2183 status by the configuration function. This option
2184 will require a board or device specific function to
2189 If defined, a function that provides delays in the FPGA
2190 configuration driver.
2192 CONFIG_SYS_FPGA_CHECK_CTRLC
2193 Allow Control-C to interrupt FPGA configuration
2195 CONFIG_SYS_FPGA_CHECK_ERROR
2197 Check for configuration errors during FPGA bitfile
2198 loading. For example, abort during Virtex II
2199 configuration if the INIT_B line goes low (which
2200 indicated a CRC error).
2202 CONFIG_SYS_FPGA_WAIT_INIT
2204 Maximum time to wait for the INIT_B line to deassert
2205 after PROB_B has been deasserted during a Virtex II
2206 FPGA configuration sequence. The default time is 500
2209 CONFIG_SYS_FPGA_WAIT_BUSY
2211 Maximum time to wait for BUSY to deassert during
2212 Virtex II FPGA configuration. The default is 5 ms.
2214 CONFIG_SYS_FPGA_WAIT_CONFIG
2216 Time to wait after FPGA configuration. The default is
2219 - Configuration Management:
2222 If defined, this string will be added to the U-Boot
2223 version information (U_BOOT_VERSION)
2225 - Vendor Parameter Protection:
2227 U-Boot considers the values of the environment
2228 variables "serial#" (Board Serial Number) and
2229 "ethaddr" (Ethernet Address) to be parameters that
2230 are set once by the board vendor / manufacturer, and
2231 protects these variables from casual modification by
2232 the user. Once set, these variables are read-only,
2233 and write or delete attempts are rejected. You can
2234 change this behaviour:
2236 If CONFIG_ENV_OVERWRITE is #defined in your config
2237 file, the write protection for vendor parameters is
2238 completely disabled. Anybody can change or delete
2241 Alternatively, if you #define _both_ CONFIG_ETHADDR
2242 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2243 Ethernet address is installed in the environment,
2244 which can be changed exactly ONCE by the user. [The
2245 serial# is unaffected by this, i. e. it remains
2248 The same can be accomplished in a more flexible way
2249 for any variable by configuring the type of access
2250 to allow for those variables in the ".flags" variable
2251 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2256 Define this variable to enable the reservation of
2257 "protected RAM", i. e. RAM which is not overwritten
2258 by U-Boot. Define CONFIG_PRAM to hold the number of
2259 kB you want to reserve for pRAM. You can overwrite
2260 this default value by defining an environment
2261 variable "pram" to the number of kB you want to
2262 reserve. Note that the board info structure will
2263 still show the full amount of RAM. If pRAM is
2264 reserved, a new environment variable "mem" will
2265 automatically be defined to hold the amount of
2266 remaining RAM in a form that can be passed as boot
2267 argument to Linux, for instance like that:
2269 setenv bootargs ... mem=\${mem}
2272 This way you can tell Linux not to use this memory,
2273 either, which results in a memory region that will
2274 not be affected by reboots.
2276 *WARNING* If your board configuration uses automatic
2277 detection of the RAM size, you must make sure that
2278 this memory test is non-destructive. So far, the
2279 following board configurations are known to be
2282 IVMS8, IVML24, SPD8xx, TQM8xxL,
2283 HERMES, IP860, RPXlite, LWMON,
2286 - Access to physical memory region (> 4GB)
2287 Some basic support is provided for operations on memory not
2288 normally accessible to U-Boot - e.g. some architectures
2289 support access to more than 4GB of memory on 32-bit
2290 machines using physical address extension or similar.
2291 Define CONFIG_PHYSMEM to access this basic support, which
2292 currently only supports clearing the memory.
2297 Define this variable to stop the system in case of a
2298 fatal error, so that you have to reset it manually.
2299 This is probably NOT a good idea for an embedded
2300 system where you want the system to reboot
2301 automatically as fast as possible, but it may be
2302 useful during development since you can try to debug
2303 the conditions that lead to the situation.
2305 CONFIG_NET_RETRY_COUNT
2307 This variable defines the number of retries for
2308 network operations like ARP, RARP, TFTP, or BOOTP
2309 before giving up the operation. If not defined, a
2310 default value of 5 is used.
2314 Timeout waiting for an ARP reply in milliseconds.
2318 Timeout in milliseconds used in NFS protocol.
2319 If you encounter "ERROR: Cannot umount" in nfs command,
2320 try longer timeout such as
2321 #define CONFIG_NFS_TIMEOUT 10000UL
2323 - Command Interpreter:
2324 CONFIG_AUTO_COMPLETE
2326 Enable auto completion of commands using TAB.
2328 Note that this feature has NOT been implemented yet
2329 for the "hush" shell.
2332 CONFIG_SYS_HUSH_PARSER
2334 Define this variable to enable the "hush" shell (from
2335 Busybox) as command line interpreter, thus enabling
2336 powerful command line syntax like
2337 if...then...else...fi conditionals or `&&' and '||'
2338 constructs ("shell scripts").
2340 If undefined, you get the old, much simpler behaviour
2341 with a somewhat smaller memory footprint.
2344 CONFIG_SYS_PROMPT_HUSH_PS2
2346 This defines the secondary prompt string, which is
2347 printed when the command interpreter needs more input
2348 to complete a command. Usually "> ".
2352 In the current implementation, the local variables
2353 space and global environment variables space are
2354 separated. Local variables are those you define by
2355 simply typing `name=value'. To access a local
2356 variable later on, you have write `$name' or
2357 `${name}'; to execute the contents of a variable
2358 directly type `$name' at the command prompt.
2360 Global environment variables are those you use
2361 setenv/printenv to work with. To run a command stored
2362 in such a variable, you need to use the run command,
2363 and you must not use the '$' sign to access them.
2365 To store commands and special characters in a
2366 variable, please use double quotation marks
2367 surrounding the whole text of the variable, instead
2368 of the backslashes before semicolons and special
2371 - Commandline Editing and History:
2372 CONFIG_CMDLINE_EDITING
2374 Enable editing and History functions for interactive
2375 commandline input operations
2377 - Default Environment:
2378 CONFIG_EXTRA_ENV_SETTINGS
2380 Define this to contain any number of null terminated
2381 strings (variable = value pairs) that will be part of
2382 the default environment compiled into the boot image.
2384 For example, place something like this in your
2385 board's config file:
2387 #define CONFIG_EXTRA_ENV_SETTINGS \
2391 Warning: This method is based on knowledge about the
2392 internal format how the environment is stored by the
2393 U-Boot code. This is NOT an official, exported
2394 interface! Although it is unlikely that this format
2395 will change soon, there is no guarantee either.
2396 You better know what you are doing here.
2398 Note: overly (ab)use of the default environment is
2399 discouraged. Make sure to check other ways to preset
2400 the environment like the "source" command or the
2403 CONFIG_ENV_VARS_UBOOT_CONFIG
2405 Define this in order to add variables describing the
2406 U-Boot build configuration to the default environment.
2407 These will be named arch, cpu, board, vendor, and soc.
2409 Enabling this option will cause the following to be defined:
2417 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2419 Define this in order to add variables describing certain
2420 run-time determined information about the hardware to the
2421 environment. These will be named board_name, board_rev.
2423 CONFIG_DELAY_ENVIRONMENT
2425 Normally the environment is loaded when the board is
2426 intialised so that it is available to U-Boot. This inhibits
2427 that so that the environment is not available until
2428 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2429 this is instead controlled by the value of
2430 /config/load-environment.
2432 - DataFlash Support:
2433 CONFIG_HAS_DATAFLASH
2435 Defining this option enables DataFlash features and
2436 allows to read/write in Dataflash via the standard
2439 - Serial Flash support
2442 Defining this option enables SPI flash commands
2443 'sf probe/read/write/erase/update'.
2445 Usage requires an initial 'probe' to define the serial
2446 flash parameters, followed by read/write/erase/update
2449 The following defaults may be provided by the platform
2450 to handle the common case when only a single serial
2451 flash is present on the system.
2453 CONFIG_SF_DEFAULT_BUS Bus identifier
2454 CONFIG_SF_DEFAULT_CS Chip-select
2455 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2456 CONFIG_SF_DEFAULT_SPEED in Hz
2460 Define this option to include a destructive SPI flash
2463 - SystemACE Support:
2466 Adding this option adds support for Xilinx SystemACE
2467 chips attached via some sort of local bus. The address
2468 of the chip must also be defined in the
2469 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2471 #define CONFIG_SYSTEMACE
2472 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2474 When SystemACE support is added, the "ace" device type
2475 becomes available to the fat commands, i.e. fatls.
2477 - TFTP Fixed UDP Port:
2480 If this is defined, the environment variable tftpsrcp
2481 is used to supply the TFTP UDP source port value.
2482 If tftpsrcp isn't defined, the normal pseudo-random port
2483 number generator is used.
2485 Also, the environment variable tftpdstp is used to supply
2486 the TFTP UDP destination port value. If tftpdstp isn't
2487 defined, the normal port 69 is used.
2489 The purpose for tftpsrcp is to allow a TFTP server to
2490 blindly start the TFTP transfer using the pre-configured
2491 target IP address and UDP port. This has the effect of
2492 "punching through" the (Windows XP) firewall, allowing
2493 the remainder of the TFTP transfer to proceed normally.
2494 A better solution is to properly configure the firewall,
2495 but sometimes that is not allowed.
2500 This enables a generic 'hash' command which can produce
2501 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2505 Enable the hash verify command (hash -v). This adds to code
2508 CONFIG_SHA1 - support SHA1 hashing
2509 CONFIG_SHA256 - support SHA256 hashing
2511 Note: There is also a sha1sum command, which should perhaps
2512 be deprecated in favour of 'hash sha1'.
2514 - Show boot progress:
2515 CONFIG_SHOW_BOOT_PROGRESS
2517 Defining this option allows to add some board-
2518 specific code (calling a user-provided function
2519 "show_boot_progress(int)") that enables you to show
2520 the system's boot progress on some display (for
2521 example, some LED's) on your board. At the moment,
2522 the following checkpoints are implemented:
2524 - Detailed boot stage timing
2526 Define this option to get detailed timing of each stage
2527 of the boot process.
2529 CONFIG_BOOTSTAGE_USER_COUNT
2530 This is the number of available user bootstage records.
2531 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2532 a new ID will be allocated from this stash. If you exceed
2533 the limit, recording will stop.
2535 CONFIG_BOOTSTAGE_REPORT
2536 Define this to print a report before boot, similar to this:
2538 Timer summary in microseconds:
2541 3,575,678 3,575,678 board_init_f start
2542 3,575,695 17 arch_cpu_init A9
2543 3,575,777 82 arch_cpu_init done
2544 3,659,598 83,821 board_init_r start
2545 3,910,375 250,777 main_loop
2546 29,916,167 26,005,792 bootm_start
2547 30,361,327 445,160 start_kernel
2549 CONFIG_CMD_BOOTSTAGE
2550 Add a 'bootstage' command which supports printing a report
2551 and un/stashing of bootstage data.
2553 CONFIG_BOOTSTAGE_FDT
2554 Stash the bootstage information in the FDT. A root 'bootstage'
2555 node is created with each bootstage id as a child. Each child
2556 has a 'name' property and either 'mark' containing the
2557 mark time in microsecond, or 'accum' containing the
2558 accumulated time for that bootstage id in microseconds.
2563 name = "board_init_f";
2572 Code in the Linux kernel can find this in /proc/devicetree.
2574 Legacy uImage format:
2577 1 common/cmd_bootm.c before attempting to boot an image
2578 -1 common/cmd_bootm.c Image header has bad magic number
2579 2 common/cmd_bootm.c Image header has correct magic number
2580 -2 common/cmd_bootm.c Image header has bad checksum
2581 3 common/cmd_bootm.c Image header has correct checksum
2582 -3 common/cmd_bootm.c Image data has bad checksum
2583 4 common/cmd_bootm.c Image data has correct checksum
2584 -4 common/cmd_bootm.c Image is for unsupported architecture
2585 5 common/cmd_bootm.c Architecture check OK
2586 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2587 6 common/cmd_bootm.c Image Type check OK
2588 -6 common/cmd_bootm.c gunzip uncompression error
2589 -7 common/cmd_bootm.c Unimplemented compression type
2590 7 common/cmd_bootm.c Uncompression OK
2591 8 common/cmd_bootm.c No uncompress/copy overwrite error
2592 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2594 9 common/image.c Start initial ramdisk verification
2595 -10 common/image.c Ramdisk header has bad magic number
2596 -11 common/image.c Ramdisk header has bad checksum
2597 10 common/image.c Ramdisk header is OK
2598 -12 common/image.c Ramdisk data has bad checksum
2599 11 common/image.c Ramdisk data has correct checksum
2600 12 common/image.c Ramdisk verification complete, start loading
2601 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2602 13 common/image.c Start multifile image verification
2603 14 common/image.c No initial ramdisk, no multifile, continue.
2605 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2607 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2608 -31 post/post.c POST test failed, detected by post_output_backlog()
2609 -32 post/post.c POST test failed, detected by post_run_single()
2611 34 common/cmd_doc.c before loading a Image from a DOC device
2612 -35 common/cmd_doc.c Bad usage of "doc" command
2613 35 common/cmd_doc.c correct usage of "doc" command
2614 -36 common/cmd_doc.c No boot device
2615 36 common/cmd_doc.c correct boot device
2616 -37 common/cmd_doc.c Unknown Chip ID on boot device
2617 37 common/cmd_doc.c correct chip ID found, device available
2618 -38 common/cmd_doc.c Read Error on boot device
2619 38 common/cmd_doc.c reading Image header from DOC device OK
2620 -39 common/cmd_doc.c Image header has bad magic number
2621 39 common/cmd_doc.c Image header has correct magic number
2622 -40 common/cmd_doc.c Error reading Image from DOC device
2623 40 common/cmd_doc.c Image header has correct magic number
2624 41 common/cmd_ide.c before loading a Image from a IDE device
2625 -42 common/cmd_ide.c Bad usage of "ide" command
2626 42 common/cmd_ide.c correct usage of "ide" command
2627 -43 common/cmd_ide.c No boot device
2628 43 common/cmd_ide.c boot device found
2629 -44 common/cmd_ide.c Device not available
2630 44 common/cmd_ide.c Device available
2631 -45 common/cmd_ide.c wrong partition selected
2632 45 common/cmd_ide.c partition selected
2633 -46 common/cmd_ide.c Unknown partition table
2634 46 common/cmd_ide.c valid partition table found
2635 -47 common/cmd_ide.c Invalid partition type
2636 47 common/cmd_ide.c correct partition type
2637 -48 common/cmd_ide.c Error reading Image Header on boot device
2638 48 common/cmd_ide.c reading Image Header from IDE device OK
2639 -49 common/cmd_ide.c Image header has bad magic number
2640 49 common/cmd_ide.c Image header has correct magic number
2641 -50 common/cmd_ide.c Image header has bad checksum
2642 50 common/cmd_ide.c Image header has correct checksum
2643 -51 common/cmd_ide.c Error reading Image from IDE device
2644 51 common/cmd_ide.c reading Image from IDE device OK
2645 52 common/cmd_nand.c before loading a Image from a NAND device
2646 -53 common/cmd_nand.c Bad usage of "nand" command
2647 53 common/cmd_nand.c correct usage of "nand" command
2648 -54 common/cmd_nand.c No boot device
2649 54 common/cmd_nand.c boot device found
2650 -55 common/cmd_nand.c Unknown Chip ID on boot device
2651 55 common/cmd_nand.c correct chip ID found, device available
2652 -56 common/cmd_nand.c Error reading Image Header on boot device
2653 56 common/cmd_nand.c reading Image Header from NAND device OK
2654 -57 common/cmd_nand.c Image header has bad magic number
2655 57 common/cmd_nand.c Image header has correct magic number
2656 -58 common/cmd_nand.c Error reading Image from NAND device
2657 58 common/cmd_nand.c reading Image from NAND device OK
2659 -60 common/env_common.c Environment has a bad CRC, using default
2661 64 net/eth.c starting with Ethernet configuration.
2662 -64 net/eth.c no Ethernet found.
2663 65 net/eth.c Ethernet found.
2665 -80 common/cmd_net.c usage wrong
2666 80 common/cmd_net.c before calling NetLoop()
2667 -81 common/cmd_net.c some error in NetLoop() occurred
2668 81 common/cmd_net.c NetLoop() back without error
2669 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2670 82 common/cmd_net.c trying automatic boot
2671 83 common/cmd_net.c running "source" command
2672 -83 common/cmd_net.c some error in automatic boot or "source" command
2673 84 common/cmd_net.c end without errors
2678 100 common/cmd_bootm.c Kernel FIT Image has correct format
2679 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2680 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2681 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2682 102 common/cmd_bootm.c Kernel unit name specified
2683 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2684 103 common/cmd_bootm.c Found configuration node
2685 104 common/cmd_bootm.c Got kernel subimage node offset
2686 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2687 105 common/cmd_bootm.c Kernel subimage hash verification OK
2688 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2689 106 common/cmd_bootm.c Architecture check OK
2690 -106 common/cmd_bootm.c Kernel subimage has wrong type
2691 107 common/cmd_bootm.c Kernel subimage type OK
2692 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2693 108 common/cmd_bootm.c Got kernel subimage data/size
2694 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2695 -109 common/cmd_bootm.c Can't get kernel subimage type
2696 -110 common/cmd_bootm.c Can't get kernel subimage comp
2697 -111 common/cmd_bootm.c Can't get kernel subimage os
2698 -112 common/cmd_bootm.c Can't get kernel subimage load address
2699 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2701 120 common/image.c Start initial ramdisk verification
2702 -120 common/image.c Ramdisk FIT image has incorrect format
2703 121 common/image.c Ramdisk FIT image has correct format
2704 122 common/image.c No ramdisk subimage unit name, using configuration
2705 -122 common/image.c Can't get configuration for ramdisk subimage
2706 123 common/image.c Ramdisk unit name specified
2707 -124 common/image.c Can't get ramdisk subimage node offset
2708 125 common/image.c Got ramdisk subimage node offset
2709 -125 common/image.c Ramdisk subimage hash verification failed
2710 126 common/image.c Ramdisk subimage hash verification OK
2711 -126 common/image.c Ramdisk subimage for unsupported architecture
2712 127 common/image.c Architecture check OK
2713 -127 common/image.c Can't get ramdisk subimage data/size
2714 128 common/image.c Got ramdisk subimage data/size
2715 129 common/image.c Can't get ramdisk load address
2716 -129 common/image.c Got ramdisk load address
2718 -130 common/cmd_doc.c Incorrect FIT image format
2719 131 common/cmd_doc.c FIT image format OK
2721 -140 common/cmd_ide.c Incorrect FIT image format
2722 141 common/cmd_ide.c FIT image format OK
2724 -150 common/cmd_nand.c Incorrect FIT image format
2725 151 common/cmd_nand.c FIT image format OK
2727 - FIT image support:
2729 Enable support for the FIT uImage format.
2731 CONFIG_FIT_BEST_MATCH
2732 When no configuration is explicitly selected, default to the
2733 one whose fdt's compatibility field best matches that of
2734 U-Boot itself. A match is considered "best" if it matches the
2735 most specific compatibility entry of U-Boot's fdt's root node.
2736 The order of entries in the configuration's fdt is ignored.
2738 - Standalone program support:
2739 CONFIG_STANDALONE_LOAD_ADDR
2741 This option defines a board specific value for the
2742 address where standalone program gets loaded, thus
2743 overwriting the architecture dependent default
2746 - Frame Buffer Address:
2749 Define CONFIG_FB_ADDR if you want to use specific
2750 address for frame buffer. This is typically the case
2751 when using a graphics controller has separate video
2752 memory. U-Boot will then place the frame buffer at
2753 the given address instead of dynamically reserving it
2754 in system RAM by calling lcd_setmem(), which grabs
2755 the memory for the frame buffer depending on the
2756 configured panel size.
2758 Please see board_init_f function.
2760 - Automatic software updates via TFTP server
2762 CONFIG_UPDATE_TFTP_CNT_MAX
2763 CONFIG_UPDATE_TFTP_MSEC_MAX
2765 These options enable and control the auto-update feature;
2766 for a more detailed description refer to doc/README.update.
2768 - MTD Support (mtdparts command, UBI support)
2771 Adds the MTD device infrastructure from the Linux kernel.
2772 Needed for mtdparts command support.
2774 CONFIG_MTD_PARTITIONS
2776 Adds the MTD partitioning infrastructure from the Linux
2777 kernel. Needed for UBI support.
2781 Enable building of SPL globally.
2784 LDSCRIPT for linking the SPL binary.
2787 Maximum binary size (text, data and rodata) of the SPL binary.
2789 CONFIG_SPL_TEXT_BASE
2790 TEXT_BASE for linking the SPL binary.
2792 CONFIG_SPL_RELOC_TEXT_BASE
2793 Address to relocate to. If unspecified, this is equal to
2794 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2796 CONFIG_SPL_BSS_START_ADDR
2797 Link address for the BSS within the SPL binary.
2799 CONFIG_SPL_BSS_MAX_SIZE
2800 Maximum binary size of the BSS section of the SPL binary.
2803 Adress of the start of the stack SPL will use
2805 CONFIG_SPL_RELOC_STACK
2806 Adress of the start of the stack SPL will use after
2807 relocation. If unspecified, this is equal to
2810 CONFIG_SYS_SPL_MALLOC_START
2811 Starting address of the malloc pool used in SPL.
2813 CONFIG_SYS_SPL_MALLOC_SIZE
2814 The size of the malloc pool used in SPL.
2816 CONFIG_SPL_FRAMEWORK
2817 Enable the SPL framework under common/. This framework
2818 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2819 NAND loading of the Linux Kernel.
2821 CONFIG_SPL_DISPLAY_PRINT
2822 For ARM, enable an optional function to print more information
2823 about the running system.
2825 CONFIG_SPL_INIT_MINIMAL
2826 Arch init code should be built for a very small image
2828 CONFIG_SPL_LIBCOMMON_SUPPORT
2829 Support for common/libcommon.o in SPL binary
2831 CONFIG_SPL_LIBDISK_SUPPORT
2832 Support for disk/libdisk.o in SPL binary
2834 CONFIG_SPL_I2C_SUPPORT
2835 Support for drivers/i2c/libi2c.o in SPL binary
2837 CONFIG_SPL_GPIO_SUPPORT
2838 Support for drivers/gpio/libgpio.o in SPL binary
2840 CONFIG_SPL_MMC_SUPPORT
2841 Support for drivers/mmc/libmmc.o in SPL binary
2843 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2844 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2845 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2846 Address, size and partition on the MMC to load U-Boot from
2847 when the MMC is being used in raw mode.
2849 CONFIG_SPL_FAT_SUPPORT
2850 Support for fs/fat/libfat.o in SPL binary
2852 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2853 Filename to read to load U-Boot when reading from FAT
2855 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2856 Set this for NAND SPL on PPC mpc83xx targets, so that
2857 start.S waits for the rest of the SPL to load before
2858 continuing (the hardware starts execution after just
2859 loading the first page rather than the full 4K).
2861 CONFIG_SPL_NAND_BASE
2862 Include nand_base.c in the SPL. Requires
2863 CONFIG_SPL_NAND_DRIVERS.
2865 CONFIG_SPL_NAND_DRIVERS
2866 SPL uses normal NAND drivers, not minimal drivers.
2869 Include standard software ECC in the SPL
2871 CONFIG_SPL_NAND_SIMPLE
2872 Support for NAND boot using simple NAND drivers that
2873 expose the cmd_ctrl() interface.
2875 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2876 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2877 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2878 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2879 CONFIG_SYS_NAND_ECCBYTES
2880 Defines the size and behavior of the NAND that SPL uses
2883 CONFIG_SYS_NAND_U_BOOT_OFFS
2884 Location in NAND to read U-Boot from
2886 CONFIG_SYS_NAND_U_BOOT_DST
2887 Location in memory to load U-Boot to
2889 CONFIG_SYS_NAND_U_BOOT_SIZE
2890 Size of image to load
2892 CONFIG_SYS_NAND_U_BOOT_START
2893 Entry point in loaded image to jump to
2895 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2896 Define this if you need to first read the OOB and then the
2897 data. This is used for example on davinci plattforms.
2899 CONFIG_SPL_OMAP3_ID_NAND
2900 Support for an OMAP3-specific set of functions to return the
2901 ID and MFR of the first attached NAND chip, if present.
2903 CONFIG_SPL_SERIAL_SUPPORT
2904 Support for drivers/serial/libserial.o in SPL binary
2906 CONFIG_SPL_SPI_FLASH_SUPPORT
2907 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2909 CONFIG_SPL_SPI_SUPPORT
2910 Support for drivers/spi/libspi.o in SPL binary
2912 CONFIG_SPL_RAM_DEVICE
2913 Support for running image already present in ram, in SPL binary
2915 CONFIG_SPL_LIBGENERIC_SUPPORT
2916 Support for lib/libgeneric.o in SPL binary
2919 Linker address to which the SPL should be padded before
2920 appending the SPL payload.
2923 Final target image containing SPL and payload. Some SPLs
2924 use an arch-specific makefile fragment instead, for
2925 example if more than one image needs to be produced.
2930 [so far only for SMDK2400 boards]
2932 - Modem support enable:
2933 CONFIG_MODEM_SUPPORT
2935 - RTS/CTS Flow control enable:
2938 - Modem debug support:
2939 CONFIG_MODEM_SUPPORT_DEBUG
2941 Enables debugging stuff (char screen[1024], dbg())
2942 for modem support. Useful only with BDI2000.
2944 - Interrupt support (PPC):
2946 There are common interrupt_init() and timer_interrupt()
2947 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2948 for CPU specific initialization. interrupt_init_cpu()
2949 should set decrementer_count to appropriate value. If
2950 CPU resets decrementer automatically after interrupt
2951 (ppc4xx) it should set decrementer_count to zero.
2952 timer_interrupt() calls timer_interrupt_cpu() for CPU
2953 specific handling. If board has watchdog / status_led
2954 / other_activity_monitor it works automatically from
2955 general timer_interrupt().
2959 In the target system modem support is enabled when a
2960 specific key (key combination) is pressed during
2961 power-on. Otherwise U-Boot will boot normally
2962 (autoboot). The key_pressed() function is called from
2963 board_init(). Currently key_pressed() is a dummy
2964 function, returning 1 and thus enabling modem
2967 If there are no modem init strings in the
2968 environment, U-Boot proceed to autoboot; the
2969 previous output (banner, info printfs) will be
2972 See also: doc/README.Modem
2974 Board initialization settings:
2975 ------------------------------
2977 During Initialization u-boot calls a number of board specific functions
2978 to allow the preparation of board specific prerequisites, e.g. pin setup
2979 before drivers are initialized. To enable these callbacks the
2980 following configuration macros have to be defined. Currently this is
2981 architecture specific, so please check arch/your_architecture/lib/board.c
2982 typically in board_init_f() and board_init_r().
2984 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2985 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2986 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2987 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2989 Configuration Settings:
2990 -----------------------
2992 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2993 undefine this when you're short of memory.
2995 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2996 width of the commands listed in the 'help' command output.
2998 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2999 prompt for user input.
3001 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3003 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3005 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3007 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3008 the application (usually a Linux kernel) when it is
3011 - CONFIG_SYS_BAUDRATE_TABLE:
3012 List of legal baudrate settings for this board.
3014 - CONFIG_SYS_CONSOLE_INFO_QUIET
3015 Suppress display of console information at boot.
3017 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3018 If the board specific function
3019 extern int overwrite_console (void);
3020 returns 1, the stdin, stderr and stdout are switched to the
3021 serial port, else the settings in the environment are used.
3023 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3024 Enable the call to overwrite_console().
3026 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3027 Enable overwrite of previous console environment settings.
3029 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3030 Begin and End addresses of the area used by the
3033 - CONFIG_SYS_ALT_MEMTEST:
3034 Enable an alternate, more extensive memory test.
3036 - CONFIG_SYS_MEMTEST_SCRATCH:
3037 Scratch address used by the alternate memory test
3038 You only need to set this if address zero isn't writeable
3040 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3041 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3042 this specified memory area will get subtracted from the top
3043 (end) of RAM and won't get "touched" at all by U-Boot. By
3044 fixing up gd->ram_size the Linux kernel should gets passed
3045 the now "corrected" memory size and won't touch it either.
3046 This should work for arch/ppc and arch/powerpc. Only Linux
3047 board ports in arch/powerpc with bootwrapper support that
3048 recalculate the memory size from the SDRAM controller setup
3049 will have to get fixed in Linux additionally.
3051 This option can be used as a workaround for the 440EPx/GRx
3052 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3055 WARNING: Please make sure that this value is a multiple of
3056 the Linux page size (normally 4k). If this is not the case,
3057 then the end address of the Linux memory will be located at a
3058 non page size aligned address and this could cause major
3061 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3062 Enable temporary baudrate change while serial download
3064 - CONFIG_SYS_SDRAM_BASE:
3065 Physical start address of SDRAM. _Must_ be 0 here.
3067 - CONFIG_SYS_MBIO_BASE:
3068 Physical start address of Motherboard I/O (if using a
3071 - CONFIG_SYS_FLASH_BASE:
3072 Physical start address of Flash memory.
3074 - CONFIG_SYS_MONITOR_BASE:
3075 Physical start address of boot monitor code (set by
3076 make config files to be same as the text base address
3077 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3078 CONFIG_SYS_FLASH_BASE when booting from flash.
3080 - CONFIG_SYS_MONITOR_LEN:
3081 Size of memory reserved for monitor code, used to
3082 determine _at_compile_time_ (!) if the environment is
3083 embedded within the U-Boot image, or in a separate
3086 - CONFIG_SYS_MALLOC_LEN:
3087 Size of DRAM reserved for malloc() use.
3089 - CONFIG_SYS_BOOTM_LEN:
3090 Normally compressed uImages are limited to an
3091 uncompressed size of 8 MBytes. If this is not enough,
3092 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3093 to adjust this setting to your needs.
3095 - CONFIG_SYS_BOOTMAPSZ:
3096 Maximum size of memory mapped by the startup code of
3097 the Linux kernel; all data that must be processed by
3098 the Linux kernel (bd_info, boot arguments, FDT blob if
3099 used) must be put below this limit, unless "bootm_low"
3100 enviroment variable is defined and non-zero. In such case
3101 all data for the Linux kernel must be between "bootm_low"
3102 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3103 variable "bootm_mapsize" will override the value of
3104 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3105 then the value in "bootm_size" will be used instead.
3107 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3108 Enable initrd_high functionality. If defined then the
3109 initrd_high feature is enabled and the bootm ramdisk subcommand
3112 - CONFIG_SYS_BOOT_GET_CMDLINE:
3113 Enables allocating and saving kernel cmdline in space between
3114 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3116 - CONFIG_SYS_BOOT_GET_KBD:
3117 Enables allocating and saving a kernel copy of the bd_info in
3118 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3120 - CONFIG_SYS_MAX_FLASH_BANKS:
3121 Max number of Flash memory banks
3123 - CONFIG_SYS_MAX_FLASH_SECT:
3124 Max number of sectors on a Flash chip
3126 - CONFIG_SYS_FLASH_ERASE_TOUT:
3127 Timeout for Flash erase operations (in ms)
3129 - CONFIG_SYS_FLASH_WRITE_TOUT:
3130 Timeout for Flash write operations (in ms)
3132 - CONFIG_SYS_FLASH_LOCK_TOUT
3133 Timeout for Flash set sector lock bit operation (in ms)
3135 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3136 Timeout for Flash clear lock bits operation (in ms)
3138 - CONFIG_SYS_FLASH_PROTECTION
3139 If defined, hardware flash sectors protection is used
3140 instead of U-Boot software protection.
3142 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3144 Enable TFTP transfers directly to flash memory;
3145 without this option such a download has to be
3146 performed in two steps: (1) download to RAM, and (2)
3147 copy from RAM to flash.
3149 The two-step approach is usually more reliable, since
3150 you can check if the download worked before you erase
3151 the flash, but in some situations (when system RAM is
3152 too limited to allow for a temporary copy of the
3153 downloaded image) this option may be very useful.
3155 - CONFIG_SYS_FLASH_CFI:
3156 Define if the flash driver uses extra elements in the
3157 common flash structure for storing flash geometry.
3159 - CONFIG_FLASH_CFI_DRIVER
3160 This option also enables the building of the cfi_flash driver
3161 in the drivers directory
3163 - CONFIG_FLASH_CFI_MTD
3164 This option enables the building of the cfi_mtd driver
3165 in the drivers directory. The driver exports CFI flash
3168 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3169 Use buffered writes to flash.
3171 - CONFIG_FLASH_SPANSION_S29WS_N
3172 s29ws-n MirrorBit flash has non-standard addresses for buffered
3175 - CONFIG_SYS_FLASH_QUIET_TEST
3176 If this option is defined, the common CFI flash doesn't
3177 print it's warning upon not recognized FLASH banks. This
3178 is useful, if some of the configured banks are only
3179 optionally available.
3181 - CONFIG_FLASH_SHOW_PROGRESS
3182 If defined (must be an integer), print out countdown
3183 digits and dots. Recommended value: 45 (9..1) for 80
3184 column displays, 15 (3..1) for 40 column displays.
3186 - CONFIG_SYS_RX_ETH_BUFFER:
3187 Defines the number of Ethernet receive buffers. On some
3188 Ethernet controllers it is recommended to set this value
3189 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3190 buffers can be full shortly after enabling the interface
3191 on high Ethernet traffic.
3192 Defaults to 4 if not defined.
3194 - CONFIG_ENV_MAX_ENTRIES
3196 Maximum number of entries in the hash table that is used
3197 internally to store the environment settings. The default
3198 setting is supposed to be generous and should work in most
3199 cases. This setting can be used to tune behaviour; see
3200 lib/hashtable.c for details.
3202 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3203 - CONFIG_ENV_FLAGS_LIST_STATIC
3204 Enable validation of the values given to enviroment variables when
3205 calling env set. Variables can be restricted to only decimal,
3206 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3207 the variables can also be restricted to IP address or MAC address.
3209 The format of the list is:
3210 type_attribute = [s|d|x|b|i|m]
3211 access_atribute = [a|r|o|c]
3212 attributes = type_attribute[access_atribute]
3213 entry = variable_name[:attributes]
3216 The type attributes are:
3217 s - String (default)
3220 b - Boolean ([1yYtT|0nNfF])
3224 The access attributes are:
3230 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3231 Define this to a list (string) to define the ".flags"
3232 envirnoment variable in the default or embedded environment.
3234 - CONFIG_ENV_FLAGS_LIST_STATIC
3235 Define this to a list (string) to define validation that
3236 should be done if an entry is not found in the ".flags"
3237 environment variable. To override a setting in the static
3238 list, simply add an entry for the same variable name to the
3241 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3242 If defined, don't allow the -f switch to env set override variable
3245 - CONFIG_SYS_GENERIC_BOARD
3246 This selects the architecture-generic board system instead of the
3247 architecture-specific board files. It is intended to move boards
3248 to this new framework over time. Defining this will disable the
3249 arch/foo/lib/board.c file and use common/board_f.c and
3250 common/board_r.c instead. To use this option your architecture
3251 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3252 its config.mk file). If you find problems enabling this option on
3253 your board please report the problem and send patches!
3255 - CONFIG_SYS_SYM_OFFSETS
3256 This is set by architectures that use offsets for link symbols
3257 instead of absolute values. So bss_start is obtained using an
3258 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3259 directly. You should not need to touch this setting.
3262 The following definitions that deal with the placement and management
3263 of environment data (variable area); in general, we support the
3264 following configurations:
3266 - CONFIG_BUILD_ENVCRC:
3268 Builds up envcrc with the target environment so that external utils
3269 may easily extract it and embed it in final U-Boot images.
3271 - CONFIG_ENV_IS_IN_FLASH:
3273 Define this if the environment is in flash memory.
3275 a) The environment occupies one whole flash sector, which is
3276 "embedded" in the text segment with the U-Boot code. This
3277 happens usually with "bottom boot sector" or "top boot
3278 sector" type flash chips, which have several smaller
3279 sectors at the start or the end. For instance, such a
3280 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3281 such a case you would place the environment in one of the
3282 4 kB sectors - with U-Boot code before and after it. With
3283 "top boot sector" type flash chips, you would put the
3284 environment in one of the last sectors, leaving a gap
3285 between U-Boot and the environment.
3287 - CONFIG_ENV_OFFSET:
3289 Offset of environment data (variable area) to the
3290 beginning of flash memory; for instance, with bottom boot
3291 type flash chips the second sector can be used: the offset
3292 for this sector is given here.
3294 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3298 This is just another way to specify the start address of
3299 the flash sector containing the environment (instead of
3302 - CONFIG_ENV_SECT_SIZE:
3304 Size of the sector containing the environment.
3307 b) Sometimes flash chips have few, equal sized, BIG sectors.
3308 In such a case you don't want to spend a whole sector for
3313 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3314 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3315 of this flash sector for the environment. This saves
3316 memory for the RAM copy of the environment.
3318 It may also save flash memory if you decide to use this
3319 when your environment is "embedded" within U-Boot code,
3320 since then the remainder of the flash sector could be used
3321 for U-Boot code. It should be pointed out that this is
3322 STRONGLY DISCOURAGED from a robustness point of view:
3323 updating the environment in flash makes it always
3324 necessary to erase the WHOLE sector. If something goes
3325 wrong before the contents has been restored from a copy in
3326 RAM, your target system will be dead.
3328 - CONFIG_ENV_ADDR_REDUND
3329 CONFIG_ENV_SIZE_REDUND
3331 These settings describe a second storage area used to hold
3332 a redundant copy of the environment data, so that there is
3333 a valid backup copy in case there is a power failure during
3334 a "saveenv" operation.
3336 BE CAREFUL! Any changes to the flash layout, and some changes to the
3337 source code will make it necessary to adapt <board>/u-boot.lds*
3341 - CONFIG_ENV_IS_IN_NVRAM:
3343 Define this if you have some non-volatile memory device
3344 (NVRAM, battery buffered SRAM) which you want to use for the
3350 These two #defines are used to determine the memory area you
3351 want to use for environment. It is assumed that this memory
3352 can just be read and written to, without any special
3355 BE CAREFUL! The first access to the environment happens quite early
3356 in U-Boot initalization (when we try to get the setting of for the
3357 console baudrate). You *MUST* have mapped your NVRAM area then, or
3360 Please note that even with NVRAM we still use a copy of the
3361 environment in RAM: we could work on NVRAM directly, but we want to
3362 keep settings there always unmodified except somebody uses "saveenv"
3363 to save the current settings.
3366 - CONFIG_ENV_IS_IN_EEPROM:
3368 Use this if you have an EEPROM or similar serial access
3369 device and a driver for it.
3371 - CONFIG_ENV_OFFSET:
3374 These two #defines specify the offset and size of the
3375 environment area within the total memory of your EEPROM.
3377 - CONFIG_SYS_I2C_EEPROM_ADDR:
3378 If defined, specified the chip address of the EEPROM device.
3379 The default address is zero.
3381 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3382 If defined, the number of bits used to address bytes in a
3383 single page in the EEPROM device. A 64 byte page, for example
3384 would require six bits.
3386 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3387 If defined, the number of milliseconds to delay between
3388 page writes. The default is zero milliseconds.
3390 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3391 The length in bytes of the EEPROM memory array address. Note
3392 that this is NOT the chip address length!
3394 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3395 EEPROM chips that implement "address overflow" are ones
3396 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3397 address and the extra bits end up in the "chip address" bit
3398 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3401 Note that we consider the length of the address field to
3402 still be one byte because the extra address bits are hidden
3403 in the chip address.
3405 - CONFIG_SYS_EEPROM_SIZE:
3406 The size in bytes of the EEPROM device.
3408 - CONFIG_ENV_EEPROM_IS_ON_I2C
3409 define this, if you have I2C and SPI activated, and your
3410 EEPROM, which holds the environment, is on the I2C bus.
3412 - CONFIG_I2C_ENV_EEPROM_BUS
3413 if you have an Environment on an EEPROM reached over
3414 I2C muxes, you can define here, how to reach this
3415 EEPROM. For example:
3417 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3419 EEPROM which holds the environment, is reached over
3420 a pca9547 i2c mux with address 0x70, channel 3.
3422 - CONFIG_ENV_IS_IN_DATAFLASH:
3424 Define this if you have a DataFlash memory device which you
3425 want to use for the environment.
3427 - CONFIG_ENV_OFFSET:
3431 These three #defines specify the offset and size of the
3432 environment area within the total memory of your DataFlash placed
3433 at the specified address.
3435 - CONFIG_ENV_IS_IN_REMOTE:
3437 Define this if you have a remote memory space which you
3438 want to use for the local device's environment.
3443 These two #defines specify the address and size of the
3444 environment area within the remote memory space. The
3445 local device can get the environment from remote memory
3446 space by SRIO or PCIE links.
3448 BE CAREFUL! For some special cases, the local device can not use
3449 "saveenv" command. For example, the local device will get the
3450 environment stored in a remote NOR flash by SRIO or PCIE link,
3451 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3453 - CONFIG_ENV_IS_IN_NAND:
3455 Define this if you have a NAND device which you want to use
3456 for the environment.
3458 - CONFIG_ENV_OFFSET:
3461 These two #defines specify the offset and size of the environment
3462 area within the first NAND device. CONFIG_ENV_OFFSET must be
3463 aligned to an erase block boundary.
3465 - CONFIG_ENV_OFFSET_REDUND (optional):
3467 This setting describes a second storage area of CONFIG_ENV_SIZE
3468 size used to hold a redundant copy of the environment data, so
3469 that there is a valid backup copy in case there is a power failure
3470 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3471 aligned to an erase block boundary.
3473 - CONFIG_ENV_RANGE (optional):
3475 Specifies the length of the region in which the environment
3476 can be written. This should be a multiple of the NAND device's
3477 block size. Specifying a range with more erase blocks than
3478 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3479 the range to be avoided.
3481 - CONFIG_ENV_OFFSET_OOB (optional):
3483 Enables support for dynamically retrieving the offset of the
3484 environment from block zero's out-of-band data. The
3485 "nand env.oob" command can be used to record this offset.
3486 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3487 using CONFIG_ENV_OFFSET_OOB.
3489 - CONFIG_NAND_ENV_DST
3491 Defines address in RAM to which the nand_spl code should copy the
3492 environment. If redundant environment is used, it will be copied to
3493 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3495 - CONFIG_SYS_SPI_INIT_OFFSET
3497 Defines offset to the initial SPI buffer area in DPRAM. The
3498 area is used at an early stage (ROM part) if the environment
3499 is configured to reside in the SPI EEPROM: We need a 520 byte
3500 scratch DPRAM area. It is used between the two initialization
3501 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3502 to be a good choice since it makes it far enough from the
3503 start of the data area as well as from the stack pointer.
3505 Please note that the environment is read-only until the monitor
3506 has been relocated to RAM and a RAM copy of the environment has been
3507 created; also, when using EEPROM you will have to use getenv_f()
3508 until then to read environment variables.
3510 The environment is protected by a CRC32 checksum. Before the monitor
3511 is relocated into RAM, as a result of a bad CRC you will be working
3512 with the compiled-in default environment - *silently*!!! [This is
3513 necessary, because the first environment variable we need is the
3514 "baudrate" setting for the console - if we have a bad CRC, we don't
3515 have any device yet where we could complain.]
3517 Note: once the monitor has been relocated, then it will complain if
3518 the default environment is used; a new CRC is computed as soon as you
3519 use the "saveenv" command to store a valid environment.
3521 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3522 Echo the inverted Ethernet link state to the fault LED.
3524 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3525 also needs to be defined.
3527 - CONFIG_SYS_FAULT_MII_ADDR:
3528 MII address of the PHY to check for the Ethernet link state.
3530 - CONFIG_NS16550_MIN_FUNCTIONS:
3531 Define this if you desire to only have use of the NS16550_init
3532 and NS16550_putc functions for the serial driver located at
3533 drivers/serial/ns16550.c. This option is useful for saving
3534 space for already greatly restricted images, including but not
3535 limited to NAND_SPL configurations.
3537 - CONFIG_DISPLAY_BOARDINFO
3538 Display information about the board that U-Boot is running on
3539 when U-Boot starts up. The board function checkboard() is called
3542 - CONFIG_DISPLAY_BOARDINFO_LATE
3543 Similar to the previous option, but display this information
3544 later, once stdio is running and output goes to the LCD, if
3547 Low Level (hardware related) configuration options:
3548 ---------------------------------------------------
3550 - CONFIG_SYS_CACHELINE_SIZE:
3551 Cache Line Size of the CPU.
3553 - CONFIG_SYS_DEFAULT_IMMR:
3554 Default address of the IMMR after system reset.
3556 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3557 and RPXsuper) to be able to adjust the position of
3558 the IMMR register after a reset.
3560 - CONFIG_SYS_CCSRBAR_DEFAULT:
3561 Default (power-on reset) physical address of CCSR on Freescale
3564 - CONFIG_SYS_CCSRBAR:
3565 Virtual address of CCSR. On a 32-bit build, this is typically
3566 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3568 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3569 for cross-platform code that uses that macro instead.
3571 - CONFIG_SYS_CCSRBAR_PHYS:
3572 Physical address of CCSR. CCSR can be relocated to a new
3573 physical address, if desired. In this case, this macro should
3574 be set to that address. Otherwise, it should be set to the
3575 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3576 is typically relocated on 36-bit builds. It is recommended
3577 that this macro be defined via the _HIGH and _LOW macros:
3579 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3580 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3582 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3583 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3584 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3585 used in assembly code, so it must not contain typecasts or
3586 integer size suffixes (e.g. "ULL").
3588 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3589 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3590 used in assembly code, so it must not contain typecasts or
3591 integer size suffixes (e.g. "ULL").
3593 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3594 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3595 forced to a value that ensures that CCSR is not relocated.
3597 - Floppy Disk Support:
3598 CONFIG_SYS_FDC_DRIVE_NUMBER
3600 the default drive number (default value 0)
3602 CONFIG_SYS_ISA_IO_STRIDE
3604 defines the spacing between FDC chipset registers
3607 CONFIG_SYS_ISA_IO_OFFSET
3609 defines the offset of register from address. It
3610 depends on which part of the data bus is connected to
3611 the FDC chipset. (default value 0)
3613 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3614 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3617 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3618 fdc_hw_init() is called at the beginning of the FDC
3619 setup. fdc_hw_init() must be provided by the board
3620 source code. It is used to make hardware dependant
3624 Most IDE controllers were designed to be connected with PCI
3625 interface. Only few of them were designed for AHB interface.
3626 When software is doing ATA command and data transfer to
3627 IDE devices through IDE-AHB controller, some additional
3628 registers accessing to these kind of IDE-AHB controller
3631 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3632 DO NOT CHANGE unless you know exactly what you're
3633 doing! (11-4) [MPC8xx/82xx systems only]
3635 - CONFIG_SYS_INIT_RAM_ADDR:
3637 Start address of memory area that can be used for
3638 initial data and stack; please note that this must be
3639 writable memory that is working WITHOUT special
3640 initialization, i. e. you CANNOT use normal RAM which
3641 will become available only after programming the
3642 memory controller and running certain initialization
3645 U-Boot uses the following memory types:
3646 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3647 - MPC824X: data cache
3648 - PPC4xx: data cache
3650 - CONFIG_SYS_GBL_DATA_OFFSET:
3652 Offset of the initial data structure in the memory
3653 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3654 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3655 data is located at the end of the available space
3656 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3657 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3658 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3659 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3662 On the MPC824X (or other systems that use the data
3663 cache for initial memory) the address chosen for
3664 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3665 point to an otherwise UNUSED address space between
3666 the top of RAM and the start of the PCI space.
3668 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3670 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3672 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3674 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3676 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3678 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3680 - CONFIG_SYS_OR_TIMING_SDRAM:
3683 - CONFIG_SYS_MAMR_PTA:
3684 periodic timer for refresh
3686 - CONFIG_SYS_DER: Debug Event Register (37-47)
3688 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3689 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3690 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3691 CONFIG_SYS_BR1_PRELIM:
3692 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3694 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3695 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3696 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3697 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3699 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3700 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3701 Machine Mode Register and Memory Periodic Timer
3702 Prescaler definitions (SDRAM timing)
3704 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3705 enable I2C microcode relocation patch (MPC8xx);
3706 define relocation offset in DPRAM [DSP2]
3708 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3709 enable SMC microcode relocation patch (MPC8xx);
3710 define relocation offset in DPRAM [SMC1]
3712 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3713 enable SPI microcode relocation patch (MPC8xx);
3714 define relocation offset in DPRAM [SCC4]
3716 - CONFIG_SYS_USE_OSCCLK:
3717 Use OSCM clock mode on MBX8xx board. Be careful,
3718 wrong setting might damage your board. Read
3719 doc/README.MBX before setting this variable!
3721 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3722 Offset of the bootmode word in DPRAM used by post
3723 (Power On Self Tests). This definition overrides
3724 #define'd default value in commproc.h resp.
3727 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3728 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3729 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3730 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3731 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3732 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3733 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3734 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3735 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3737 - CONFIG_PCI_DISABLE_PCIE:
3738 Disable PCI-Express on systems where it is supported but not
3741 - CONFIG_PCI_ENUM_ONLY
3742 Only scan through and get the devices on the busses.
3743 Don't do any setup work, presumably because someone or
3744 something has already done it, and we don't need to do it
3745 a second time. Useful for platforms that are pre-booted
3746 by coreboot or similar.
3749 Chip has SRIO or not
3752 Board has SRIO 1 port available
3755 Board has SRIO 2 port available
3757 - CONFIG_SYS_SRIOn_MEM_VIRT:
3758 Virtual Address of SRIO port 'n' memory region
3760 - CONFIG_SYS_SRIOn_MEM_PHYS:
3761 Physical Address of SRIO port 'n' memory region
3763 - CONFIG_SYS_SRIOn_MEM_SIZE:
3764 Size of SRIO port 'n' memory region
3766 - CONFIG_SYS_NDFC_16
3767 Defined to tell the NDFC that the NAND chip is using a
3770 - CONFIG_SYS_NDFC_EBC0_CFG
3771 Sets the EBC0_CFG register for the NDFC. If not defined
3772 a default value will be used.
3775 Get DDR timing information from an I2C EEPROM. Common
3776 with pluggable memory modules such as SODIMMs
3779 I2C address of the SPD EEPROM
3781 - CONFIG_SYS_SPD_BUS_NUM
3782 If SPD EEPROM is on an I2C bus other than the first
3783 one, specify here. Note that the value must resolve
3784 to something your driver can deal with.
3786 - CONFIG_SYS_DDR_RAW_TIMING
3787 Get DDR timing information from other than SPD. Common with
3788 soldered DDR chips onboard without SPD. DDR raw timing
3789 parameters are extracted from datasheet and hard-coded into
3790 header files or board specific files.
3792 - CONFIG_FSL_DDR_INTERACTIVE
3793 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3795 - CONFIG_SYS_83XX_DDR_USES_CS0
3796 Only for 83xx systems. If specified, then DDR should
3797 be configured using CS0 and CS1 instead of CS2 and CS3.
3799 - CONFIG_ETHER_ON_FEC[12]
3800 Define to enable FEC[12] on a 8xx series processor.
3802 - CONFIG_FEC[12]_PHY
3803 Define to the hardcoded PHY address which corresponds
3804 to the given FEC; i. e.
3805 #define CONFIG_FEC1_PHY 4
3806 means that the PHY with address 4 is connected to FEC1
3808 When set to -1, means to probe for first available.
3810 - CONFIG_FEC[12]_PHY_NORXERR
3811 The PHY does not have a RXERR line (RMII only).
3812 (so program the FEC to ignore it).
3815 Enable RMII mode for all FECs.
3816 Note that this is a global option, we can't
3817 have one FEC in standard MII mode and another in RMII mode.
3819 - CONFIG_CRC32_VERIFY
3820 Add a verify option to the crc32 command.
3823 => crc32 -v <address> <count> <crc32>
3825 Where address/count indicate a memory area
3826 and crc32 is the correct crc32 which the
3830 Add the "loopw" memory command. This only takes effect if
3831 the memory commands are activated globally (CONFIG_CMD_MEM).
3834 Add the "mdc" and "mwc" memory commands. These are cyclic
3839 This command will print 4 bytes (10,11,12,13) each 500 ms.
3841 => mwc.l 100 12345678 10
3842 This command will write 12345678 to address 100 all 10 ms.
3844 This only takes effect if the memory commands are activated
3845 globally (CONFIG_CMD_MEM).
3847 - CONFIG_SKIP_LOWLEVEL_INIT
3848 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3849 low level initializations (like setting up the memory
3850 controller) are omitted and/or U-Boot does not
3851 relocate itself into RAM.
3853 Normally this variable MUST NOT be defined. The only
3854 exception is when U-Boot is loaded (to RAM) by some
3855 other boot loader or by a debugger which performs
3856 these initializations itself.
3859 Modifies the behaviour of start.S when compiling a loader
3860 that is executed before the actual U-Boot. E.g. when
3861 compiling a NAND SPL.
3863 - CONFIG_ARCH_MAP_SYSMEM
3864 Generally U-Boot (and in particular the md command) uses
3865 effective address. It is therefore not necessary to regard
3866 U-Boot address as virtual addresses that need to be translated
3867 to physical addresses. However, sandbox requires this, since
3868 it maintains its own little RAM buffer which contains all
3869 addressable memory. This option causes some memory accesses
3870 to be mapped through map_sysmem() / unmap_sysmem().
3872 - CONFIG_USE_ARCH_MEMCPY
3873 CONFIG_USE_ARCH_MEMSET
3874 If these options are used a optimized version of memcpy/memset will
3875 be used if available. These functions may be faster under some
3876 conditions but may increase the binary size.
3878 - CONFIG_X86_RESET_VECTOR
3879 If defined, the x86 reset vector code is included. This is not
3880 needed when U-Boot is running from Coreboot.
3883 Defines the MPU clock speed (in MHz).
3885 NOTE : currently only supported on AM335x platforms.
3887 Freescale QE/FMAN Firmware Support:
3888 -----------------------------------
3890 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3891 loading of "firmware", which is encoded in the QE firmware binary format.
3892 This firmware often needs to be loaded during U-Boot booting, so macros
3893 are used to identify the storage device (NOR flash, SPI, etc) and the address
3896 - CONFIG_SYS_QE_FMAN_FW_ADDR
3897 The address in the storage device where the firmware is located. The
3898 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3901 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3902 The maximum possible size of the firmware. The firmware binary format
3903 has a field that specifies the actual size of the firmware, but it
3904 might not be possible to read any part of the firmware unless some
3905 local storage is allocated to hold the entire firmware first.
3907 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3908 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3909 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3910 virtual address in NOR flash.
3912 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3913 Specifies that QE/FMAN firmware is located in NAND flash.
3914 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3916 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3917 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3918 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3920 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3921 Specifies that QE/FMAN firmware is located on the primary SPI
3922 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3924 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3925 Specifies that QE/FMAN firmware is located in the remote (master)
3926 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3927 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3928 window->master inbound window->master LAW->the ucode address in
3929 master's memory space.
3931 Building the Software:
3932 ======================
3934 Building U-Boot has been tested in several native build environments
3935 and in many different cross environments. Of course we cannot support
3936 all possibly existing versions of cross development tools in all
3937 (potentially obsolete) versions. In case of tool chain problems we
3938 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3939 which is extensively used to build and test U-Boot.
3941 If you are not using a native environment, it is assumed that you
3942 have GNU cross compiling tools available in your path. In this case,
3943 you must set the environment variable CROSS_COMPILE in your shell.
3944 Note that no changes to the Makefile or any other source files are
3945 necessary. For example using the ELDK on a 4xx CPU, please enter:
3947 $ CROSS_COMPILE=ppc_4xx-
3948 $ export CROSS_COMPILE
3950 Note: If you wish to generate Windows versions of the utilities in
3951 the tools directory you can use the MinGW toolchain
3952 (http://www.mingw.org). Set your HOST tools to the MinGW
3953 toolchain and execute 'make tools'. For example:
3955 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3957 Binaries such as tools/mkimage.exe will be created which can
3958 be executed on computers running Windows.
3960 U-Boot is intended to be simple to build. After installing the
3961 sources you must configure U-Boot for one specific board type. This
3966 where "NAME_config" is the name of one of the existing configu-
3967 rations; see boards.cfg for supported names.
3969 Note: for some board special configuration names may exist; check if
3970 additional information is available from the board vendor; for
3971 instance, the TQM823L systems are available without (standard)
3972 or with LCD support. You can select such additional "features"
3973 when choosing the configuration, i. e.
3976 - will configure for a plain TQM823L, i. e. no LCD support
3978 make TQM823L_LCD_config
3979 - will configure for a TQM823L with U-Boot console on LCD
3984 Finally, type "make all", and you should get some working U-Boot
3985 images ready for download to / installation on your system:
3987 - "u-boot.bin" is a raw binary image
3988 - "u-boot" is an image in ELF binary format
3989 - "u-boot.srec" is in Motorola S-Record format
3991 By default the build is performed locally and the objects are saved
3992 in the source directory. One of the two methods can be used to change
3993 this behavior and build U-Boot to some external directory:
3995 1. Add O= to the make command line invocations:
3997 make O=/tmp/build distclean
3998 make O=/tmp/build NAME_config
3999 make O=/tmp/build all
4001 2. Set environment variable BUILD_DIR to point to the desired location:
4003 export BUILD_DIR=/tmp/build
4008 Note that the command line "O=" setting overrides the BUILD_DIR environment
4012 Please be aware that the Makefiles assume you are using GNU make, so
4013 for instance on NetBSD you might need to use "gmake" instead of
4017 If the system board that you have is not listed, then you will need
4018 to port U-Boot to your hardware platform. To do this, follow these
4021 1. Add a new configuration option for your board to the toplevel
4022 "boards.cfg" file, using the existing entries as examples.
4023 Follow the instructions there to keep the boards in order.
4024 2. Create a new directory to hold your board specific code. Add any
4025 files you need. In your board directory, you will need at least
4026 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4027 3. Create a new configuration file "include/configs/<board>.h" for
4029 3. If you're porting U-Boot to a new CPU, then also create a new
4030 directory to hold your CPU specific code. Add any files you need.
4031 4. Run "make <board>_config" with your new name.
4032 5. Type "make", and you should get a working "u-boot.srec" file
4033 to be installed on your target system.
4034 6. Debug and solve any problems that might arise.
4035 [Of course, this last step is much harder than it sounds.]
4038 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4039 ==============================================================
4041 If you have modified U-Boot sources (for instance added a new board
4042 or support for new devices, a new CPU, etc.) you are expected to
4043 provide feedback to the other developers. The feedback normally takes
4044 the form of a "patch", i. e. a context diff against a certain (latest
4045 official or latest in the git repository) version of U-Boot sources.
4047 But before you submit such a patch, please verify that your modifi-
4048 cation did not break existing code. At least make sure that *ALL* of
4049 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4050 just run the "MAKEALL" script, which will configure and build U-Boot
4051 for ALL supported system. Be warned, this will take a while. You can
4052 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4053 environment variable to the script, i. e. to use the ELDK cross tools
4056 CROSS_COMPILE=ppc_8xx- MAKEALL
4058 or to build on a native PowerPC system you can type
4060 CROSS_COMPILE=' ' MAKEALL
4062 When using the MAKEALL script, the default behaviour is to build
4063 U-Boot in the source directory. This location can be changed by
4064 setting the BUILD_DIR environment variable. Also, for each target
4065 built, the MAKEALL script saves two log files (<target>.ERR and
4066 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4067 location can be changed by setting the MAKEALL_LOGDIR environment
4068 variable. For example:
4070 export BUILD_DIR=/tmp/build
4071 export MAKEALL_LOGDIR=/tmp/log
4072 CROSS_COMPILE=ppc_8xx- MAKEALL
4074 With the above settings build objects are saved in the /tmp/build,
4075 log files are saved in the /tmp/log and the source tree remains clean
4076 during the whole build process.
4079 See also "U-Boot Porting Guide" below.
4082 Monitor Commands - Overview:
4083 ============================
4085 go - start application at address 'addr'
4086 run - run commands in an environment variable
4087 bootm - boot application image from memory
4088 bootp - boot image via network using BootP/TFTP protocol
4089 bootz - boot zImage from memory
4090 tftpboot- boot image via network using TFTP protocol
4091 and env variables "ipaddr" and "serverip"
4092 (and eventually "gatewayip")
4093 tftpput - upload a file via network using TFTP protocol
4094 rarpboot- boot image via network using RARP/TFTP protocol
4095 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4096 loads - load S-Record file over serial line
4097 loadb - load binary file over serial line (kermit mode)
4099 mm - memory modify (auto-incrementing)
4100 nm - memory modify (constant address)
4101 mw - memory write (fill)
4103 cmp - memory compare
4104 crc32 - checksum calculation
4105 i2c - I2C sub-system
4106 sspi - SPI utility commands
4107 base - print or set address offset
4108 printenv- print environment variables
4109 setenv - set environment variables
4110 saveenv - save environment variables to persistent storage
4111 protect - enable or disable FLASH write protection
4112 erase - erase FLASH memory
4113 flinfo - print FLASH memory information
4114 nand - NAND memory operations (see doc/README.nand)
4115 bdinfo - print Board Info structure
4116 iminfo - print header information for application image
4117 coninfo - print console devices and informations
4118 ide - IDE sub-system
4119 loop - infinite loop on address range
4120 loopw - infinite write loop on address range
4121 mtest - simple RAM test
4122 icache - enable or disable instruction cache
4123 dcache - enable or disable data cache
4124 reset - Perform RESET of the CPU
4125 echo - echo args to console
4126 version - print monitor version
4127 help - print online help
4128 ? - alias for 'help'
4131 Monitor Commands - Detailed Description:
4132 ========================================
4136 For now: just type "help <command>".
4139 Environment Variables:
4140 ======================
4142 U-Boot supports user configuration using Environment Variables which
4143 can be made persistent by saving to Flash memory.
4145 Environment Variables are set using "setenv", printed using
4146 "printenv", and saved to Flash using "saveenv". Using "setenv"
4147 without a value can be used to delete a variable from the
4148 environment. As long as you don't save the environment you are
4149 working with an in-memory copy. In case the Flash area containing the
4150 environment is erased by accident, a default environment is provided.
4152 Some configuration options can be set using Environment Variables.
4154 List of environment variables (most likely not complete):
4156 baudrate - see CONFIG_BAUDRATE
4158 bootdelay - see CONFIG_BOOTDELAY
4160 bootcmd - see CONFIG_BOOTCOMMAND
4162 bootargs - Boot arguments when booting an RTOS image
4164 bootfile - Name of the image to load with TFTP
4166 bootm_low - Memory range available for image processing in the bootm
4167 command can be restricted. This variable is given as
4168 a hexadecimal number and defines lowest address allowed
4169 for use by the bootm command. See also "bootm_size"
4170 environment variable. Address defined by "bootm_low" is
4171 also the base of the initial memory mapping for the Linux
4172 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4175 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4176 This variable is given as a hexadecimal number and it
4177 defines the size of the memory region starting at base
4178 address bootm_low that is accessible by the Linux kernel
4179 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4180 as the default value if it is defined, and bootm_size is
4183 bootm_size - Memory range available for image processing in the bootm
4184 command can be restricted. This variable is given as
4185 a hexadecimal number and defines the size of the region
4186 allowed for use by the bootm command. See also "bootm_low"
4187 environment variable.
4189 updatefile - Location of the software update file on a TFTP server, used
4190 by the automatic software update feature. Please refer to
4191 documentation in doc/README.update for more details.
4193 autoload - if set to "no" (any string beginning with 'n'),
4194 "bootp" will just load perform a lookup of the
4195 configuration from the BOOTP server, but not try to
4196 load any image using TFTP
4198 autostart - if set to "yes", an image loaded using the "bootp",
4199 "rarpboot", "tftpboot" or "diskboot" commands will
4200 be automatically started (by internally calling
4203 If set to "no", a standalone image passed to the
4204 "bootm" command will be copied to the load address
4205 (and eventually uncompressed), but NOT be started.
4206 This can be used to load and uncompress arbitrary
4209 fdt_high - if set this restricts the maximum address that the
4210 flattened device tree will be copied into upon boot.
4211 For example, if you have a system with 1 GB memory
4212 at physical address 0x10000000, while Linux kernel
4213 only recognizes the first 704 MB as low memory, you
4214 may need to set fdt_high as 0x3C000000 to have the
4215 device tree blob be copied to the maximum address
4216 of the 704 MB low memory, so that Linux kernel can
4217 access it during the boot procedure.
4219 If this is set to the special value 0xFFFFFFFF then
4220 the fdt will not be copied at all on boot. For this
4221 to work it must reside in writable memory, have
4222 sufficient padding on the end of it for u-boot to
4223 add the information it needs into it, and the memory
4224 must be accessible by the kernel.
4226 fdtcontroladdr- if set this is the address of the control flattened
4227 device tree used by U-Boot when CONFIG_OF_CONTROL is
4230 i2cfast - (PPC405GP|PPC405EP only)
4231 if set to 'y' configures Linux I2C driver for fast
4232 mode (400kHZ). This environment variable is used in
4233 initialization code. So, for changes to be effective
4234 it must be saved and board must be reset.
4236 initrd_high - restrict positioning of initrd images:
4237 If this variable is not set, initrd images will be
4238 copied to the highest possible address in RAM; this
4239 is usually what you want since it allows for
4240 maximum initrd size. If for some reason you want to
4241 make sure that the initrd image is loaded below the
4242 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4243 variable to a value of "no" or "off" or "0".
4244 Alternatively, you can set it to a maximum upper
4245 address to use (U-Boot will still check that it
4246 does not overwrite the U-Boot stack and data).
4248 For instance, when you have a system with 16 MB
4249 RAM, and want to reserve 4 MB from use by Linux,
4250 you can do this by adding "mem=12M" to the value of
4251 the "bootargs" variable. However, now you must make
4252 sure that the initrd image is placed in the first
4253 12 MB as well - this can be done with
4255 setenv initrd_high 00c00000
4257 If you set initrd_high to 0xFFFFFFFF, this is an
4258 indication to U-Boot that all addresses are legal
4259 for the Linux kernel, including addresses in flash
4260 memory. In this case U-Boot will NOT COPY the
4261 ramdisk at all. This may be useful to reduce the
4262 boot time on your system, but requires that this
4263 feature is supported by your Linux kernel.
4265 ipaddr - IP address; needed for tftpboot command
4267 loadaddr - Default load address for commands like "bootp",
4268 "rarpboot", "tftpboot", "loadb" or "diskboot"
4270 loads_echo - see CONFIG_LOADS_ECHO
4272 serverip - TFTP server IP address; needed for tftpboot command
4274 bootretry - see CONFIG_BOOT_RETRY_TIME
4276 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4278 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4280 ethprime - controls which interface is used first.
4282 ethact - controls which interface is currently active.
4283 For example you can do the following
4285 => setenv ethact FEC
4286 => ping 192.168.0.1 # traffic sent on FEC
4287 => setenv ethact SCC
4288 => ping 10.0.0.1 # traffic sent on SCC
4290 ethrotate - When set to "no" U-Boot does not go through all
4291 available network interfaces.
4292 It just stays at the currently selected interface.
4294 netretry - When set to "no" each network operation will
4295 either succeed or fail without retrying.
4296 When set to "once" the network operation will
4297 fail when all the available network interfaces
4298 are tried once without success.
4299 Useful on scripts which control the retry operation
4302 npe_ucode - set load address for the NPE microcode
4304 tftpsrcport - If this is set, the value is used for TFTP's
4307 tftpdstport - If this is set, the value is used for TFTP's UDP
4308 destination port instead of the Well Know Port 69.
4310 tftpblocksize - Block size to use for TFTP transfers; if not set,
4311 we use the TFTP server's default block size
4313 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4314 seconds, minimum value is 1000 = 1 second). Defines
4315 when a packet is considered to be lost so it has to
4316 be retransmitted. The default is 5000 = 5 seconds.
4317 Lowering this value may make downloads succeed
4318 faster in networks with high packet loss rates or
4319 with unreliable TFTP servers.
4321 vlan - When set to a value < 4095 the traffic over
4322 Ethernet is encapsulated/received over 802.1q
4325 The following image location variables contain the location of images
4326 used in booting. The "Image" column gives the role of the image and is
4327 not an environment variable name. The other columns are environment
4328 variable names. "File Name" gives the name of the file on a TFTP
4329 server, "RAM Address" gives the location in RAM the image will be
4330 loaded to, and "Flash Location" gives the image's address in NOR
4331 flash or offset in NAND flash.
4333 *Note* - these variables don't have to be defined for all boards, some
4334 boards currenlty use other variables for these purposes, and some
4335 boards use these variables for other purposes.
4337 Image File Name RAM Address Flash Location
4338 ----- --------- ----------- --------------
4339 u-boot u-boot u-boot_addr_r u-boot_addr
4340 Linux kernel bootfile kernel_addr_r kernel_addr
4341 device tree blob fdtfile fdt_addr_r fdt_addr
4342 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4344 The following environment variables may be used and automatically
4345 updated by the network boot commands ("bootp" and "rarpboot"),
4346 depending the information provided by your boot server:
4348 bootfile - see above
4349 dnsip - IP address of your Domain Name Server
4350 dnsip2 - IP address of your secondary Domain Name Server
4351 gatewayip - IP address of the Gateway (Router) to use
4352 hostname - Target hostname
4354 netmask - Subnet Mask
4355 rootpath - Pathname of the root filesystem on the NFS server
4356 serverip - see above
4359 There are two special Environment Variables:
4361 serial# - contains hardware identification information such
4362 as type string and/or serial number
4363 ethaddr - Ethernet address
4365 These variables can be set only once (usually during manufacturing of
4366 the board). U-Boot refuses to delete or overwrite these variables
4367 once they have been set once.
4370 Further special Environment Variables:
4372 ver - Contains the U-Boot version string as printed
4373 with the "version" command. This variable is
4374 readonly (see CONFIG_VERSION_VARIABLE).
4377 Please note that changes to some configuration parameters may take
4378 only effect after the next boot (yes, that's just like Windoze :-).
4381 Callback functions for environment variables:
4382 ---------------------------------------------
4384 For some environment variables, the behavior of u-boot needs to change
4385 when their values are changed. This functionailty allows functions to
4386 be associated with arbitrary variables. On creation, overwrite, or
4387 deletion, the callback will provide the opportunity for some side
4388 effect to happen or for the change to be rejected.
4390 The callbacks are named and associated with a function using the
4391 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4393 These callbacks are associated with variables in one of two ways. The
4394 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4395 in the board configuration to a string that defines a list of
4396 associations. The list must be in the following format:
4398 entry = variable_name[:callback_name]
4401 If the callback name is not specified, then the callback is deleted.
4402 Spaces are also allowed anywhere in the list.
4404 Callbacks can also be associated by defining the ".callbacks" variable
4405 with the same list format above. Any association in ".callbacks" will
4406 override any association in the static list. You can define
4407 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4408 ".callbacks" envirnoment variable in the default or embedded environment.
4411 Command Line Parsing:
4412 =====================
4414 There are two different command line parsers available with U-Boot:
4415 the old "simple" one, and the much more powerful "hush" shell:
4417 Old, simple command line parser:
4418 --------------------------------
4420 - supports environment variables (through setenv / saveenv commands)
4421 - several commands on one line, separated by ';'
4422 - variable substitution using "... ${name} ..." syntax
4423 - special characters ('$', ';') can be escaped by prefixing with '\',
4425 setenv bootcmd bootm \${address}
4426 - You can also escape text by enclosing in single apostrophes, for example:
4427 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4432 - similar to Bourne shell, with control structures like
4433 if...then...else...fi, for...do...done; while...do...done,
4434 until...do...done, ...
4435 - supports environment ("global") variables (through setenv / saveenv
4436 commands) and local shell variables (through standard shell syntax
4437 "name=value"); only environment variables can be used with "run"
4443 (1) If a command line (or an environment variable executed by a "run"
4444 command) contains several commands separated by semicolon, and
4445 one of these commands fails, then the remaining commands will be
4448 (2) If you execute several variables with one call to run (i. e.
4449 calling run with a list of variables as arguments), any failing
4450 command will cause "run" to terminate, i. e. the remaining
4451 variables are not executed.
4453 Note for Redundant Ethernet Interfaces:
4454 =======================================
4456 Some boards come with redundant Ethernet interfaces; U-Boot supports
4457 such configurations and is capable of automatic selection of a
4458 "working" interface when needed. MAC assignment works as follows:
4460 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4461 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4462 "eth1addr" (=>eth1), "eth2addr", ...
4464 If the network interface stores some valid MAC address (for instance
4465 in SROM), this is used as default address if there is NO correspon-
4466 ding setting in the environment; if the corresponding environment
4467 variable is set, this overrides the settings in the card; that means:
4469 o If the SROM has a valid MAC address, and there is no address in the
4470 environment, the SROM's address is used.
4472 o If there is no valid address in the SROM, and a definition in the
4473 environment exists, then the value from the environment variable is
4476 o If both the SROM and the environment contain a MAC address, and
4477 both addresses are the same, this MAC address is used.
4479 o If both the SROM and the environment contain a MAC address, and the
4480 addresses differ, the value from the environment is used and a
4483 o If neither SROM nor the environment contain a MAC address, an error
4486 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4487 will be programmed into hardware as part of the initialization process. This
4488 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4489 The naming convention is as follows:
4490 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4495 U-Boot is capable of booting (and performing other auxiliary operations on)
4496 images in two formats:
4498 New uImage format (FIT)
4499 -----------------------
4501 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4502 to Flattened Device Tree). It allows the use of images with multiple
4503 components (several kernels, ramdisks, etc.), with contents protected by
4504 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4510 Old image format is based on binary files which can be basically anything,
4511 preceded by a special header; see the definitions in include/image.h for
4512 details; basically, the header defines the following image properties:
4514 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4515 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4516 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4517 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4519 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4520 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4521 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4522 * Compression Type (uncompressed, gzip, bzip2)
4528 The header is marked by a special Magic Number, and both the header
4529 and the data portions of the image are secured against corruption by
4536 Although U-Boot should support any OS or standalone application
4537 easily, the main focus has always been on Linux during the design of
4540 U-Boot includes many features that so far have been part of some
4541 special "boot loader" code within the Linux kernel. Also, any
4542 "initrd" images to be used are no longer part of one big Linux image;
4543 instead, kernel and "initrd" are separate images. This implementation
4544 serves several purposes:
4546 - the same features can be used for other OS or standalone
4547 applications (for instance: using compressed images to reduce the
4548 Flash memory footprint)
4550 - it becomes much easier to port new Linux kernel versions because
4551 lots of low-level, hardware dependent stuff are done by U-Boot
4553 - the same Linux kernel image can now be used with different "initrd"
4554 images; of course this also means that different kernel images can
4555 be run with the same "initrd". This makes testing easier (you don't
4556 have to build a new "zImage.initrd" Linux image when you just
4557 change a file in your "initrd"). Also, a field-upgrade of the
4558 software is easier now.
4564 Porting Linux to U-Boot based systems:
4565 ---------------------------------------
4567 U-Boot cannot save you from doing all the necessary modifications to
4568 configure the Linux device drivers for use with your target hardware
4569 (no, we don't intend to provide a full virtual machine interface to
4572 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4574 Just make sure your machine specific header file (for instance
4575 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4576 Information structure as we define in include/asm-<arch>/u-boot.h,
4577 and make sure that your definition of IMAP_ADDR uses the same value
4578 as your U-Boot configuration in CONFIG_SYS_IMMR.
4581 Configuring the Linux kernel:
4582 -----------------------------
4584 No specific requirements for U-Boot. Make sure you have some root
4585 device (initial ramdisk, NFS) for your target system.
4588 Building a Linux Image:
4589 -----------------------
4591 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4592 not used. If you use recent kernel source, a new build target
4593 "uImage" will exist which automatically builds an image usable by
4594 U-Boot. Most older kernels also have support for a "pImage" target,
4595 which was introduced for our predecessor project PPCBoot and uses a
4596 100% compatible format.
4605 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4606 encapsulate a compressed Linux kernel image with header information,
4607 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4609 * build a standard "vmlinux" kernel image (in ELF binary format):
4611 * convert the kernel into a raw binary image:
4613 ${CROSS_COMPILE}-objcopy -O binary \
4614 -R .note -R .comment \
4615 -S vmlinux linux.bin
4617 * compress the binary image:
4621 * package compressed binary image for U-Boot:
4623 mkimage -A ppc -O linux -T kernel -C gzip \
4624 -a 0 -e 0 -n "Linux Kernel Image" \
4625 -d linux.bin.gz uImage
4628 The "mkimage" tool can also be used to create ramdisk images for use
4629 with U-Boot, either separated from the Linux kernel image, or
4630 combined into one file. "mkimage" encapsulates the images with a 64
4631 byte header containing information about target architecture,
4632 operating system, image type, compression method, entry points, time
4633 stamp, CRC32 checksums, etc.
4635 "mkimage" can be called in two ways: to verify existing images and
4636 print the header information, or to build new images.
4638 In the first form (with "-l" option) mkimage lists the information
4639 contained in the header of an existing U-Boot image; this includes
4640 checksum verification:
4642 tools/mkimage -l image
4643 -l ==> list image header information
4645 The second form (with "-d" option) is used to build a U-Boot image
4646 from a "data file" which is used as image payload:
4648 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4649 -n name -d data_file image
4650 -A ==> set architecture to 'arch'
4651 -O ==> set operating system to 'os'
4652 -T ==> set image type to 'type'
4653 -C ==> set compression type 'comp'
4654 -a ==> set load address to 'addr' (hex)
4655 -e ==> set entry point to 'ep' (hex)
4656 -n ==> set image name to 'name'
4657 -d ==> use image data from 'datafile'
4659 Right now, all Linux kernels for PowerPC systems use the same load
4660 address (0x00000000), but the entry point address depends on the
4663 - 2.2.x kernels have the entry point at 0x0000000C,
4664 - 2.3.x and later kernels have the entry point at 0x00000000.
4666 So a typical call to build a U-Boot image would read:
4668 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4669 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4670 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4671 > examples/uImage.TQM850L
4672 Image Name: 2.4.4 kernel for TQM850L
4673 Created: Wed Jul 19 02:34:59 2000
4674 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4675 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4676 Load Address: 0x00000000
4677 Entry Point: 0x00000000
4679 To verify the contents of the image (or check for corruption):
4681 -> tools/mkimage -l examples/uImage.TQM850L
4682 Image Name: 2.4.4 kernel for TQM850L
4683 Created: Wed Jul 19 02:34:59 2000
4684 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4685 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4686 Load Address: 0x00000000
4687 Entry Point: 0x00000000
4689 NOTE: for embedded systems where boot time is critical you can trade
4690 speed for memory and install an UNCOMPRESSED image instead: this
4691 needs more space in Flash, but boots much faster since it does not
4692 need to be uncompressed:
4694 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4695 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4696 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4697 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4698 > examples/uImage.TQM850L-uncompressed
4699 Image Name: 2.4.4 kernel for TQM850L
4700 Created: Wed Jul 19 02:34:59 2000
4701 Image Type: PowerPC Linux Kernel Image (uncompressed)
4702 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4703 Load Address: 0x00000000
4704 Entry Point: 0x00000000
4707 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4708 when your kernel is intended to use an initial ramdisk:
4710 -> tools/mkimage -n 'Simple Ramdisk Image' \
4711 > -A ppc -O linux -T ramdisk -C gzip \
4712 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4713 Image Name: Simple Ramdisk Image
4714 Created: Wed Jan 12 14:01:50 2000
4715 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4716 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4717 Load Address: 0x00000000
4718 Entry Point: 0x00000000
4721 Installing a Linux Image:
4722 -------------------------
4724 To downloading a U-Boot image over the serial (console) interface,
4725 you must convert the image to S-Record format:
4727 objcopy -I binary -O srec examples/image examples/image.srec
4729 The 'objcopy' does not understand the information in the U-Boot
4730 image header, so the resulting S-Record file will be relative to
4731 address 0x00000000. To load it to a given address, you need to
4732 specify the target address as 'offset' parameter with the 'loads'
4735 Example: install the image to address 0x40100000 (which on the
4736 TQM8xxL is in the first Flash bank):
4738 => erase 40100000 401FFFFF
4744 ## Ready for S-Record download ...
4745 ~>examples/image.srec
4746 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4748 15989 15990 15991 15992
4749 [file transfer complete]
4751 ## Start Addr = 0x00000000
4754 You can check the success of the download using the 'iminfo' command;
4755 this includes a checksum verification so you can be sure no data
4756 corruption happened:
4760 ## Checking Image at 40100000 ...
4761 Image Name: 2.2.13 for initrd on TQM850L
4762 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4763 Data Size: 335725 Bytes = 327 kB = 0 MB
4764 Load Address: 00000000
4765 Entry Point: 0000000c
4766 Verifying Checksum ... OK
4772 The "bootm" command is used to boot an application that is stored in
4773 memory (RAM or Flash). In case of a Linux kernel image, the contents
4774 of the "bootargs" environment variable is passed to the kernel as
4775 parameters. You can check and modify this variable using the
4776 "printenv" and "setenv" commands:
4779 => printenv bootargs
4780 bootargs=root=/dev/ram
4782 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4784 => printenv bootargs
4785 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4788 ## Booting Linux kernel at 40020000 ...
4789 Image Name: 2.2.13 for NFS on TQM850L
4790 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4791 Data Size: 381681 Bytes = 372 kB = 0 MB
4792 Load Address: 00000000
4793 Entry Point: 0000000c
4794 Verifying Checksum ... OK
4795 Uncompressing Kernel Image ... OK
4796 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
4797 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4798 time_init: decrementer frequency = 187500000/60
4799 Calibrating delay loop... 49.77 BogoMIPS
4800 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4803 If you want to boot a Linux kernel with initial RAM disk, you pass
4804 the memory addresses of both the kernel and the initrd image (PPBCOOT
4805 format!) to the "bootm" command:
4807 => imi 40100000 40200000
4809 ## Checking Image at 40100000 ...
4810 Image Name: 2.2.13 for initrd on TQM850L
4811 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4812 Data Size: 335725 Bytes = 327 kB = 0 MB
4813 Load Address: 00000000
4814 Entry Point: 0000000c
4815 Verifying Checksum ... OK
4817 ## Checking Image at 40200000 ...
4818 Image Name: Simple Ramdisk Image
4819 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4820 Data Size: 566530 Bytes = 553 kB = 0 MB
4821 Load Address: 00000000
4822 Entry Point: 00000000
4823 Verifying Checksum ... OK
4825 => bootm 40100000 40200000
4826 ## Booting Linux kernel at 40100000 ...
4827 Image Name: 2.2.13 for initrd on TQM850L
4828 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4829 Data Size: 335725 Bytes = 327 kB = 0 MB
4830 Load Address: 00000000
4831 Entry Point: 0000000c
4832 Verifying Checksum ... OK
4833 Uncompressing Kernel Image ... OK
4834 ## Loading RAMDisk Image at 40200000 ...
4835 Image Name: Simple Ramdisk Image
4836 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4837 Data Size: 566530 Bytes = 553 kB = 0 MB
4838 Load Address: 00000000
4839 Entry Point: 00000000
4840 Verifying Checksum ... OK
4841 Loading Ramdisk ... OK
4842 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
4843 Boot arguments: root=/dev/ram
4844 time_init: decrementer frequency = 187500000/60
4845 Calibrating delay loop... 49.77 BogoMIPS
4847 RAMDISK: Compressed image found at block 0
4848 VFS: Mounted root (ext2 filesystem).
4852 Boot Linux and pass a flat device tree:
4855 First, U-Boot must be compiled with the appropriate defines. See the section
4856 titled "Linux Kernel Interface" above for a more in depth explanation. The
4857 following is an example of how to start a kernel and pass an updated
4863 oft=oftrees/mpc8540ads.dtb
4864 => tftp $oftaddr $oft
4865 Speed: 1000, full duplex
4867 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4868 Filename 'oftrees/mpc8540ads.dtb'.
4869 Load address: 0x300000
4872 Bytes transferred = 4106 (100a hex)
4873 => tftp $loadaddr $bootfile
4874 Speed: 1000, full duplex
4876 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4878 Load address: 0x200000
4879 Loading:############
4881 Bytes transferred = 1029407 (fb51f hex)
4886 => bootm $loadaddr - $oftaddr
4887 ## Booting image at 00200000 ...
4888 Image Name: Linux-2.6.17-dirty
4889 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4890 Data Size: 1029343 Bytes = 1005.2 kB
4891 Load Address: 00000000
4892 Entry Point: 00000000
4893 Verifying Checksum ... OK
4894 Uncompressing Kernel Image ... OK
4895 Booting using flat device tree at 0x300000
4896 Using MPC85xx ADS machine description
4897 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4901 More About U-Boot Image Types:
4902 ------------------------------
4904 U-Boot supports the following image types:
4906 "Standalone Programs" are directly runnable in the environment
4907 provided by U-Boot; it is expected that (if they behave
4908 well) you can continue to work in U-Boot after return from
4909 the Standalone Program.
4910 "OS Kernel Images" are usually images of some Embedded OS which
4911 will take over control completely. Usually these programs
4912 will install their own set of exception handlers, device
4913 drivers, set up the MMU, etc. - this means, that you cannot
4914 expect to re-enter U-Boot except by resetting the CPU.
4915 "RAMDisk Images" are more or less just data blocks, and their
4916 parameters (address, size) are passed to an OS kernel that is
4918 "Multi-File Images" contain several images, typically an OS
4919 (Linux) kernel image and one or more data images like
4920 RAMDisks. This construct is useful for instance when you want
4921 to boot over the network using BOOTP etc., where the boot
4922 server provides just a single image file, but you want to get
4923 for instance an OS kernel and a RAMDisk image.
4925 "Multi-File Images" start with a list of image sizes, each
4926 image size (in bytes) specified by an "uint32_t" in network
4927 byte order. This list is terminated by an "(uint32_t)0".
4928 Immediately after the terminating 0 follow the images, one by
4929 one, all aligned on "uint32_t" boundaries (size rounded up to
4930 a multiple of 4 bytes).
4932 "Firmware Images" are binary images containing firmware (like
4933 U-Boot or FPGA images) which usually will be programmed to
4936 "Script files" are command sequences that will be executed by
4937 U-Boot's command interpreter; this feature is especially
4938 useful when you configure U-Boot to use a real shell (hush)
4939 as command interpreter.
4941 Booting the Linux zImage:
4942 -------------------------
4944 On some platforms, it's possible to boot Linux zImage. This is done
4945 using the "bootz" command. The syntax of "bootz" command is the same
4946 as the syntax of "bootm" command.
4948 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4949 kernel with raw initrd images. The syntax is slightly different, the
4950 address of the initrd must be augmented by it's size, in the following
4951 format: "<initrd addres>:<initrd size>".
4957 One of the features of U-Boot is that you can dynamically load and
4958 run "standalone" applications, which can use some resources of
4959 U-Boot like console I/O functions or interrupt services.
4961 Two simple examples are included with the sources:
4966 'examples/hello_world.c' contains a small "Hello World" Demo
4967 application; it is automatically compiled when you build U-Boot.
4968 It's configured to run at address 0x00040004, so you can play with it
4972 ## Ready for S-Record download ...
4973 ~>examples/hello_world.srec
4974 1 2 3 4 5 6 7 8 9 10 11 ...
4975 [file transfer complete]
4977 ## Start Addr = 0x00040004
4979 => go 40004 Hello World! This is a test.
4980 ## Starting application at 0x00040004 ...
4991 Hit any key to exit ...
4993 ## Application terminated, rc = 0x0
4995 Another example, which demonstrates how to register a CPM interrupt
4996 handler with the U-Boot code, can be found in 'examples/timer.c'.
4997 Here, a CPM timer is set up to generate an interrupt every second.
4998 The interrupt service routine is trivial, just printing a '.'
4999 character, but this is just a demo program. The application can be
5000 controlled by the following keys:
5002 ? - print current values og the CPM Timer registers
5003 b - enable interrupts and start timer
5004 e - stop timer and disable interrupts
5005 q - quit application
5008 ## Ready for S-Record download ...
5009 ~>examples/timer.srec
5010 1 2 3 4 5 6 7 8 9 10 11 ...
5011 [file transfer complete]
5013 ## Start Addr = 0x00040004
5016 ## Starting application at 0x00040004 ...
5019 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5022 [q, b, e, ?] Set interval 1000000 us
5025 [q, b, e, ?] ........
5026 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5029 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5032 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5035 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5037 [q, b, e, ?] ...Stopping timer
5039 [q, b, e, ?] ## Application terminated, rc = 0x0
5045 Over time, many people have reported problems when trying to use the
5046 "minicom" terminal emulation program for serial download. I (wd)
5047 consider minicom to be broken, and recommend not to use it. Under
5048 Unix, I recommend to use C-Kermit for general purpose use (and
5049 especially for kermit binary protocol download ("loadb" command), and
5050 use "cu" for S-Record download ("loads" command). See
5051 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5052 for help with kermit.
5055 Nevertheless, if you absolutely want to use it try adding this
5056 configuration to your "File transfer protocols" section:
5058 Name Program Name U/D FullScr IO-Red. Multi
5059 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5060 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5066 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5067 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5069 Building requires a cross environment; it is known to work on
5070 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5071 need gmake since the Makefiles are not compatible with BSD make).
5072 Note that the cross-powerpc package does not install include files;
5073 attempting to build U-Boot will fail because <machine/ansi.h> is
5074 missing. This file has to be installed and patched manually:
5076 # cd /usr/pkg/cross/powerpc-netbsd/include
5078 # ln -s powerpc machine
5079 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5080 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5082 Native builds *don't* work due to incompatibilities between native
5083 and U-Boot include files.
5085 Booting assumes that (the first part of) the image booted is a
5086 stage-2 loader which in turn loads and then invokes the kernel
5087 proper. Loader sources will eventually appear in the NetBSD source
5088 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5089 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5092 Implementation Internals:
5093 =========================
5095 The following is not intended to be a complete description of every
5096 implementation detail. However, it should help to understand the
5097 inner workings of U-Boot and make it easier to port it to custom
5101 Initial Stack, Global Data:
5102 ---------------------------
5104 The implementation of U-Boot is complicated by the fact that U-Boot
5105 starts running out of ROM (flash memory), usually without access to
5106 system RAM (because the memory controller is not initialized yet).
5107 This means that we don't have writable Data or BSS segments, and BSS
5108 is not initialized as zero. To be able to get a C environment working
5109 at all, we have to allocate at least a minimal stack. Implementation
5110 options for this are defined and restricted by the CPU used: Some CPU
5111 models provide on-chip memory (like the IMMR area on MPC8xx and
5112 MPC826x processors), on others (parts of) the data cache can be
5113 locked as (mis-) used as memory, etc.
5115 Chris Hallinan posted a good summary of these issues to the
5116 U-Boot mailing list:
5118 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5119 From: "Chris Hallinan" <clh@net1plus.com>
5120 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5123 Correct me if I'm wrong, folks, but the way I understand it
5124 is this: Using DCACHE as initial RAM for Stack, etc, does not
5125 require any physical RAM backing up the cache. The cleverness
5126 is that the cache is being used as a temporary supply of
5127 necessary storage before the SDRAM controller is setup. It's
5128 beyond the scope of this list to explain the details, but you
5129 can see how this works by studying the cache architecture and
5130 operation in the architecture and processor-specific manuals.
5132 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5133 is another option for the system designer to use as an
5134 initial stack/RAM area prior to SDRAM being available. Either
5135 option should work for you. Using CS 4 should be fine if your
5136 board designers haven't used it for something that would
5137 cause you grief during the initial boot! It is frequently not
5140 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5141 with your processor/board/system design. The default value
5142 you will find in any recent u-boot distribution in
5143 walnut.h should work for you. I'd set it to a value larger
5144 than your SDRAM module. If you have a 64MB SDRAM module, set
5145 it above 400_0000. Just make sure your board has no resources
5146 that are supposed to respond to that address! That code in
5147 start.S has been around a while and should work as is when
5148 you get the config right.
5153 It is essential to remember this, since it has some impact on the C
5154 code for the initialization procedures:
5156 * Initialized global data (data segment) is read-only. Do not attempt
5159 * Do not use any uninitialized global data (or implicitely initialized
5160 as zero data - BSS segment) at all - this is undefined, initiali-
5161 zation is performed later (when relocating to RAM).
5163 * Stack space is very limited. Avoid big data buffers or things like
5166 Having only the stack as writable memory limits means we cannot use
5167 normal global data to share information beween the code. But it
5168 turned out that the implementation of U-Boot can be greatly
5169 simplified by making a global data structure (gd_t) available to all
5170 functions. We could pass a pointer to this data as argument to _all_
5171 functions, but this would bloat the code. Instead we use a feature of
5172 the GCC compiler (Global Register Variables) to share the data: we
5173 place a pointer (gd) to the global data into a register which we
5174 reserve for this purpose.
5176 When choosing a register for such a purpose we are restricted by the
5177 relevant (E)ABI specifications for the current architecture, and by
5178 GCC's implementation.
5180 For PowerPC, the following registers have specific use:
5182 R2: reserved for system use
5183 R3-R4: parameter passing and return values
5184 R5-R10: parameter passing
5185 R13: small data area pointer
5189 (U-Boot also uses R12 as internal GOT pointer. r12
5190 is a volatile register so r12 needs to be reset when
5191 going back and forth between asm and C)
5193 ==> U-Boot will use R2 to hold a pointer to the global data
5195 Note: on PPC, we could use a static initializer (since the
5196 address of the global data structure is known at compile time),
5197 but it turned out that reserving a register results in somewhat
5198 smaller code - although the code savings are not that big (on
5199 average for all boards 752 bytes for the whole U-Boot image,
5200 624 text + 127 data).
5202 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5203 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5205 ==> U-Boot will use P3 to hold a pointer to the global data
5207 On ARM, the following registers are used:
5209 R0: function argument word/integer result
5210 R1-R3: function argument word
5212 R10: stack limit (used only if stack checking if enabled)
5213 R11: argument (frame) pointer
5214 R12: temporary workspace
5217 R15: program counter
5219 ==> U-Boot will use R8 to hold a pointer to the global data
5221 On Nios II, the ABI is documented here:
5222 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5224 ==> U-Boot will use gp to hold a pointer to the global data
5226 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5227 to access small data sections, so gp is free.
5229 On NDS32, the following registers are used:
5231 R0-R1: argument/return
5233 R15: temporary register for assembler
5234 R16: trampoline register
5235 R28: frame pointer (FP)
5236 R29: global pointer (GP)
5237 R30: link register (LP)
5238 R31: stack pointer (SP)
5239 PC: program counter (PC)
5241 ==> U-Boot will use R10 to hold a pointer to the global data
5243 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5244 or current versions of GCC may "optimize" the code too much.
5249 U-Boot runs in system state and uses physical addresses, i.e. the
5250 MMU is not used either for address mapping nor for memory protection.
5252 The available memory is mapped to fixed addresses using the memory
5253 controller. In this process, a contiguous block is formed for each
5254 memory type (Flash, SDRAM, SRAM), even when it consists of several
5255 physical memory banks.
5257 U-Boot is installed in the first 128 kB of the first Flash bank (on
5258 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5259 booting and sizing and initializing DRAM, the code relocates itself
5260 to the upper end of DRAM. Immediately below the U-Boot code some
5261 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5262 configuration setting]. Below that, a structure with global Board
5263 Info data is placed, followed by the stack (growing downward).
5265 Additionally, some exception handler code is copied to the low 8 kB
5266 of DRAM (0x00000000 ... 0x00001FFF).
5268 So a typical memory configuration with 16 MB of DRAM could look like
5271 0x0000 0000 Exception Vector code
5274 0x0000 2000 Free for Application Use
5280 0x00FB FF20 Monitor Stack (Growing downward)
5281 0x00FB FFAC Board Info Data and permanent copy of global data
5282 0x00FC 0000 Malloc Arena
5285 0x00FE 0000 RAM Copy of Monitor Code
5286 ... eventually: LCD or video framebuffer
5287 ... eventually: pRAM (Protected RAM - unchanged by reset)
5288 0x00FF FFFF [End of RAM]
5291 System Initialization:
5292 ----------------------
5294 In the reset configuration, U-Boot starts at the reset entry point
5295 (on most PowerPC systems at address 0x00000100). Because of the reset
5296 configuration for CS0# this is a mirror of the onboard Flash memory.
5297 To be able to re-map memory U-Boot then jumps to its link address.
5298 To be able to implement the initialization code in C, a (small!)
5299 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5300 which provide such a feature like MPC8xx or MPC8260), or in a locked
5301 part of the data cache. After that, U-Boot initializes the CPU core,
5302 the caches and the SIU.
5304 Next, all (potentially) available memory banks are mapped using a
5305 preliminary mapping. For example, we put them on 512 MB boundaries
5306 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5307 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5308 programmed for SDRAM access. Using the temporary configuration, a
5309 simple memory test is run that determines the size of the SDRAM
5312 When there is more than one SDRAM bank, and the banks are of
5313 different size, the largest is mapped first. For equal size, the first
5314 bank (CS2#) is mapped first. The first mapping is always for address
5315 0x00000000, with any additional banks following immediately to create
5316 contiguous memory starting from 0.
5318 Then, the monitor installs itself at the upper end of the SDRAM area
5319 and allocates memory for use by malloc() and for the global Board
5320 Info data; also, the exception vector code is copied to the low RAM
5321 pages, and the final stack is set up.
5323 Only after this relocation will you have a "normal" C environment;
5324 until that you are restricted in several ways, mostly because you are
5325 running from ROM, and because the code will have to be relocated to a
5329 U-Boot Porting Guide:
5330 ----------------------
5332 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5336 int main(int argc, char *argv[])
5338 sighandler_t no_more_time;
5340 signal(SIGALRM, no_more_time);
5341 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5343 if (available_money > available_manpower) {
5344 Pay consultant to port U-Boot;
5348 Download latest U-Boot source;
5350 Subscribe to u-boot mailing list;
5353 email("Hi, I am new to U-Boot, how do I get started?");
5356 Read the README file in the top level directory;
5357 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5358 Read applicable doc/*.README;
5359 Read the source, Luke;
5360 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5363 if (available_money > toLocalCurrency ($2500))
5366 Add a lot of aggravation and time;
5368 if (a similar board exists) { /* hopefully... */
5369 cp -a board/<similar> board/<myboard>
5370 cp include/configs/<similar>.h include/configs/<myboard>.h
5372 Create your own board support subdirectory;
5373 Create your own board include/configs/<myboard>.h file;
5375 Edit new board/<myboard> files
5376 Edit new include/configs/<myboard>.h
5381 Add / modify source code;
5385 email("Hi, I am having problems...");
5387 Send patch file to the U-Boot email list;
5388 if (reasonable critiques)
5389 Incorporate improvements from email list code review;
5391 Defend code as written;
5397 void no_more_time (int sig)
5406 All contributions to U-Boot should conform to the Linux kernel
5407 coding style; see the file "Documentation/CodingStyle" and the script
5408 "scripts/Lindent" in your Linux kernel source directory.
5410 Source files originating from a different project (for example the
5411 MTD subsystem) are generally exempt from these guidelines and are not
5412 reformated to ease subsequent migration to newer versions of those
5415 Please note that U-Boot is implemented in C (and to some small parts in
5416 Assembler); no C++ is used, so please do not use C++ style comments (//)
5419 Please also stick to the following formatting rules:
5420 - remove any trailing white space
5421 - use TAB characters for indentation and vertical alignment, not spaces
5422 - make sure NOT to use DOS '\r\n' line feeds
5423 - do not add more than 2 consecutive empty lines to source files
5424 - do not add trailing empty lines to source files
5426 Submissions which do not conform to the standards may be returned
5427 with a request to reformat the changes.
5433 Since the number of patches for U-Boot is growing, we need to
5434 establish some rules. Submissions which do not conform to these rules
5435 may be rejected, even when they contain important and valuable stuff.
5437 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5439 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5440 see http://lists.denx.de/mailman/listinfo/u-boot
5442 When you send a patch, please include the following information with
5445 * For bug fixes: a description of the bug and how your patch fixes
5446 this bug. Please try to include a way of demonstrating that the
5447 patch actually fixes something.
5449 * For new features: a description of the feature and your
5452 * A CHANGELOG entry as plaintext (separate from the patch)
5454 * For major contributions, your entry to the CREDITS file
5456 * When you add support for a new board, don't forget to add this
5457 board to the MAINTAINERS file, too.
5459 * If your patch adds new configuration options, don't forget to
5460 document these in the README file.
5462 * The patch itself. If you are using git (which is *strongly*
5463 recommended) you can easily generate the patch using the
5464 "git format-patch". If you then use "git send-email" to send it to
5465 the U-Boot mailing list, you will avoid most of the common problems
5466 with some other mail clients.
5468 If you cannot use git, use "diff -purN OLD NEW". If your version of
5469 diff does not support these options, then get the latest version of
5472 The current directory when running this command shall be the parent
5473 directory of the U-Boot source tree (i. e. please make sure that
5474 your patch includes sufficient directory information for the
5477 We prefer patches as plain text. MIME attachments are discouraged,
5478 and compressed attachments must not be used.
5480 * If one logical set of modifications affects or creates several
5481 files, all these changes shall be submitted in a SINGLE patch file.
5483 * Changesets that contain different, unrelated modifications shall be
5484 submitted as SEPARATE patches, one patch per changeset.
5489 * Before sending the patch, run the MAKEALL script on your patched
5490 source tree and make sure that no errors or warnings are reported
5491 for any of the boards.
5493 * Keep your modifications to the necessary minimum: A patch
5494 containing several unrelated changes or arbitrary reformats will be
5495 returned with a request to re-formatting / split it.
5497 * If you modify existing code, make sure that your new code does not
5498 add to the memory footprint of the code ;-) Small is beautiful!
5499 When adding new features, these should compile conditionally only
5500 (using #ifdef), and the resulting code with the new feature
5501 disabled must not need more memory than the old code without your
5504 * Remember that there is a size limit of 100 kB per message on the
5505 u-boot mailing list. Bigger patches will be moderated. If they are
5506 reasonable and not too big, they will be acknowledged. But patches
5507 bigger than the size limit should be avoided.
projects / kernel / u-boot.git / blob