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
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /x86 Files generic to x86 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /mips32 Files specific to MIPS32 CPUs
184 /xburst Files specific to Ingenic XBurst CPUs
185 /lib Architecture specific library files
186 /nds32 Files generic to NDS32 architecture
187 /cpu CPU specific files
188 /n1213 Files specific to Andes Technology N1213 CPUs
189 /lib Architecture specific library files
190 /nios2 Files generic to Altera NIOS2 architecture
191 /cpu CPU specific files
192 /lib Architecture specific library files
193 /powerpc Files generic to PowerPC architecture
194 /cpu CPU specific files
195 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
196 /mpc5xx Files specific to Freescale MPC5xx CPUs
197 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
198 /mpc8xx Files specific to Freescale MPC8xx CPUs
199 /mpc8220 Files specific to Freescale MPC8220 CPUs
200 /mpc824x Files specific to Freescale MPC824x CPUs
201 /mpc8260 Files specific to Freescale MPC8260 CPUs
202 /mpc85xx Files specific to Freescale MPC85xx CPUs
203 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
204 /lib Architecture specific library files
205 /sh Files generic to SH architecture
206 /cpu CPU specific files
207 /sh2 Files specific to sh2 CPUs
208 /sh3 Files specific to sh3 CPUs
209 /sh4 Files specific to sh4 CPUs
210 /lib Architecture specific library files
211 /sparc Files generic to SPARC architecture
212 /cpu CPU specific files
213 /leon2 Files specific to Gaisler LEON2 SPARC CPU
214 /leon3 Files specific to Gaisler LEON3 SPARC CPU
215 /lib Architecture specific library files
216 /api Machine/arch independent API for external apps
217 /board Board dependent files
218 /common Misc architecture independent functions
219 /disk Code for disk drive partition handling
220 /doc Documentation (don't expect too much)
221 /drivers Commonly used device drivers
222 /examples Example code for standalone applications, etc.
223 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
224 /include Header Files
225 /lib Files generic to all architectures
226 /libfdt Library files to support flattened device trees
227 /lzma Library files to support LZMA decompression
228 /lzo Library files to support LZO decompression
230 /post Power On Self Test
231 /rtc Real Time Clock drivers
232 /tools Tools to build S-Record or U-Boot images, etc.
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the CPU type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
294 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
296 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
297 Define exactly one, e.g. CONFIG_ATSTK1002
299 - CPU Module Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
302 --- FIXME --- not tested yet:
303 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
304 CONFIG_CMA287_23, CONFIG_CMA287_50
306 - Motherboard Type: (if CONFIG_COGENT is defined)
307 Define exactly one of
308 CONFIG_CMA101, CONFIG_CMA102
310 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
311 Define one or more of
314 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
315 Define one or more of
316 CONFIG_LCD_HEARTBEAT - update a character position on
317 the LCD display every second with
320 - Board flavour: (if CONFIG_MPC8260ADS is defined)
323 CONFIG_SYS_8260ADS - original MPC8260ADS
324 CONFIG_SYS_8266ADS - MPC8266ADS
325 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
326 CONFIG_SYS_8272ADS - MPC8272ADS
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - MPC824X Family Member (if CONFIG_MPC824X is defined)
334 Define exactly one of
335 CONFIG_MPC8240, CONFIG_MPC8245
337 - 8xx CPU Options: (if using an MPC8xx CPU)
338 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
339 get_gclk_freq() cannot work
340 e.g. if there is no 32KHz
341 reference PIT/RTC clock
342 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
345 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
346 CONFIG_SYS_8xx_CPUCLK_MIN
347 CONFIG_SYS_8xx_CPUCLK_MAX
348 CONFIG_8xx_CPUCLK_DEFAULT
349 See doc/README.MPC866
351 CONFIG_SYS_MEASURE_CPUCLK
353 Define this to measure the actual CPU clock instead
354 of relying on the correctness of the configured
355 values. Mostly useful for board bringup to make sure
356 the PLL is locked at the intended frequency. Note
357 that this requires a (stable) reference clock (32 kHz
358 RTC clock or CONFIG_SYS_8XX_XIN)
360 CONFIG_SYS_DELAYED_ICACHE
362 Define this option if you want to enable the
363 ICache only when Code runs from RAM.
368 Specifies that the core is a 64-bit PowerPC implementation (implements
369 the "64" category of the Power ISA). This is necessary for ePAPR
370 compliance, among other possible reasons.
372 CONFIG_SYS_FSL_TBCLK_DIV
374 Defines the core time base clock divider ratio compared to the
375 system clock. On most PQ3 devices this is 8, on newer QorIQ
376 devices it can be 16 or 32. The ratio varies from SoC to Soc.
378 CONFIG_SYS_FSL_PCIE_COMPAT
380 Defines the string to utilize when trying to match PCIe device
381 tree nodes for the given platform.
383 CONFIG_SYS_PPC_E500_DEBUG_TLB
385 Enables a temporary TLB entry to be used during boot to work
386 around limitations in e500v1 and e500v2 external debugger
387 support. This reduces the portions of the boot code where
388 breakpoints and single stepping do not work. The value of this
389 symbol should be set to the TLB1 entry to be used for this
392 CONFIG_SYS_FSL_ERRATUM_A004510
394 Enables a workaround for erratum A004510. If set,
395 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
396 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
398 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
399 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
401 Defines one or two SoC revisions (low 8 bits of SVR)
402 for which the A004510 workaround should be applied.
404 The rest of SVR is either not relevant to the decision
405 of whether the erratum is present (e.g. p2040 versus
406 p2041) or is implied by the build target, which controls
407 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
409 See Freescale App Note 4493 for more information about
412 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
414 This is the value to write into CCSR offset 0x18600
415 according to the A004510 workaround.
417 - Generic CPU options:
418 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
420 Defines the endianess of the CPU. Implementation of those
421 values is arch specific.
423 - Intel Monahans options:
424 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
426 Defines the Monahans run mode to oscillator
427 ratio. Valid values are 8, 16, 24, 31. The core
428 frequency is this value multiplied by 13 MHz.
430 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
432 Defines the Monahans turbo mode to oscillator
433 ratio. Valid values are 1 (default if undefined) and
434 2. The core frequency as calculated above is multiplied
438 CONFIG_SYS_INIT_SP_OFFSET
440 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
441 pointer. This is needed for the temporary stack before
444 CONFIG_SYS_MIPS_CACHE_MODE
446 Cache operation mode for the MIPS CPU.
447 See also arch/mips/include/asm/mipsregs.h.
449 CONF_CM_CACHABLE_NO_WA
452 CONF_CM_CACHABLE_NONCOHERENT
456 CONF_CM_CACHABLE_ACCELERATED
458 CONFIG_SYS_XWAY_EBU_BOOTCFG
460 Special option for Lantiq XWAY SoCs for booting from NOR flash.
461 See also arch/mips/cpu/mips32/start.S.
463 CONFIG_XWAY_SWAP_BYTES
465 Enable compilation of tools/xway-swap-bytes needed for Lantiq
466 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
467 be swapped if a flash programmer is used.
470 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
472 Select high exception vectors of the ARM core, e.g., do not
473 clear the V bit of the c1 register of CP15.
475 CONFIG_SYS_THUMB_BUILD
477 Use this flag to build U-Boot using the Thumb instruction
478 set for ARM architectures. Thumb instruction set provides
479 better code density. For ARM architectures that support
480 Thumb2 this flag will result in Thumb2 code generated by
483 - Linux Kernel Interface:
486 U-Boot stores all clock information in Hz
487 internally. For binary compatibility with older Linux
488 kernels (which expect the clocks passed in the
489 bd_info data to be in MHz) the environment variable
490 "clocks_in_mhz" can be defined so that U-Boot
491 converts clock data to MHZ before passing it to the
493 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
494 "clocks_in_mhz=1" is automatically included in the
497 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
499 When transferring memsize parameter to linux, some versions
500 expect it to be in bytes, others in MB.
501 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
505 New kernel versions are expecting firmware settings to be
506 passed using flattened device trees (based on open firmware
510 * New libfdt-based support
511 * Adds the "fdt" command
512 * The bootm command automatically updates the fdt
514 OF_CPU - The proper name of the cpus node (only required for
515 MPC512X and MPC5xxx based boards).
516 OF_SOC - The proper name of the soc node (only required for
517 MPC512X and MPC5xxx based boards).
518 OF_TBCLK - The timebase frequency.
519 OF_STDOUT_PATH - The path to the console device
521 boards with QUICC Engines require OF_QE to set UCC MAC
524 CONFIG_OF_BOARD_SETUP
526 Board code has addition modification that it wants to make
527 to the flat device tree before handing it off to the kernel
531 This define fills in the correct boot CPU in the boot
532 param header, the default value is zero if undefined.
536 U-Boot can detect if an IDE device is present or not.
537 If not, and this new config option is activated, U-Boot
538 removes the ATA node from the DTS before booting Linux,
539 so the Linux IDE driver does not probe the device and
540 crash. This is needed for buggy hardware (uc101) where
541 no pull down resistor is connected to the signal IDE5V_DD7.
543 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
545 This setting is mandatory for all boards that have only one
546 machine type and must be used to specify the machine type
547 number as it appears in the ARM machine registry
548 (see http://www.arm.linux.org.uk/developer/machines/).
549 Only boards that have multiple machine types supported
550 in a single configuration file and the machine type is
551 runtime discoverable, do not have to use this setting.
553 - vxWorks boot parameters:
555 bootvx constructs a valid bootline using the following
556 environments variables: bootfile, ipaddr, serverip, hostname.
557 It loads the vxWorks image pointed bootfile.
559 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
560 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
561 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
562 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
564 CONFIG_SYS_VXWORKS_ADD_PARAMS
566 Add it at the end of the bootline. E.g "u=username pw=secret"
568 Note: If a "bootargs" environment is defined, it will overwride
569 the defaults discussed just above.
571 - Cache Configuration:
572 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
573 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
574 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
576 - Cache Configuration for ARM:
577 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
579 CONFIG_SYS_PL310_BASE - Physical base address of PL310
580 controller register space
585 Define this if you want support for Amba PrimeCell PL010 UARTs.
589 Define this if you want support for Amba PrimeCell PL011 UARTs.
593 If you have Amba PrimeCell PL011 UARTs, set this variable to
594 the clock speed of the UARTs.
598 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
599 define this to a list of base addresses for each (supported)
600 port. See e.g. include/configs/versatile.h
602 CONFIG_PL011_SERIAL_RLCR
604 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
605 have separate receive and transmit line control registers. Set
606 this variable to initialize the extra register.
608 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
610 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
611 boot loader that has already initialized the UART. Define this
612 variable to flush the UART at init time.
616 Depending on board, define exactly one serial port
617 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
618 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
619 console by defining CONFIG_8xx_CONS_NONE
621 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
622 port routines must be defined elsewhere
623 (i.e. serial_init(), serial_getc(), ...)
626 Enables console device for a color framebuffer. Needs following
627 defines (cf. smiLynxEM, i8042)
628 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
630 VIDEO_HW_RECTFILL graphic chip supports
633 VIDEO_HW_BITBLT graphic chip supports
634 bit-blit (cf. smiLynxEM)
635 VIDEO_VISIBLE_COLS visible pixel columns
637 VIDEO_VISIBLE_ROWS visible pixel rows
638 VIDEO_PIXEL_SIZE bytes per pixel
639 VIDEO_DATA_FORMAT graphic data format
640 (0-5, cf. cfb_console.c)
641 VIDEO_FB_ADRS framebuffer address
642 VIDEO_KBD_INIT_FCT keyboard int fct
643 (i.e. i8042_kbd_init())
644 VIDEO_TSTC_FCT test char fct
646 VIDEO_GETC_FCT get char fct
648 CONFIG_CONSOLE_CURSOR cursor drawing on/off
649 (requires blink timer
651 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
652 CONFIG_CONSOLE_TIME display time/date info in
654 (requires CONFIG_CMD_DATE)
655 CONFIG_VIDEO_LOGO display Linux logo in
657 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
658 linux_logo.h for logo.
659 Requires CONFIG_VIDEO_LOGO
660 CONFIG_CONSOLE_EXTRA_INFO
661 additional board info beside
664 When CONFIG_CFB_CONSOLE is defined, video console is
665 default i/o. Serial console can be forced with
666 environment 'console=serial'.
668 When CONFIG_SILENT_CONSOLE is defined, all console
669 messages (by U-Boot and Linux!) can be silenced with
670 the "silent" environment variable. See
671 doc/README.silent for more information.
674 CONFIG_BAUDRATE - in bps
675 Select one of the baudrates listed in
676 CONFIG_SYS_BAUDRATE_TABLE, see below.
677 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
679 - Console Rx buffer length
680 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
681 the maximum receive buffer length for the SMC.
682 This option is actual only for 82xx and 8xx possible.
683 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
684 must be defined, to setup the maximum idle timeout for
687 - Pre-Console Buffer:
688 Prior to the console being initialised (i.e. serial UART
689 initialised etc) all console output is silently discarded.
690 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
691 buffer any console messages prior to the console being
692 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
693 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
694 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
695 bytes are output before the console is initialised, the
696 earlier bytes are discarded.
698 'Sane' compilers will generate smaller code if
699 CONFIG_PRE_CON_BUF_SZ is a power of 2
701 - Safe printf() functions
702 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
703 the printf() functions. These are defined in
704 include/vsprintf.h and include snprintf(), vsnprintf() and
705 so on. Code size increase is approximately 300-500 bytes.
706 If this option is not given then these functions will
707 silently discard their buffer size argument - this means
708 you are not getting any overflow checking in this case.
710 - Boot Delay: CONFIG_BOOTDELAY - in seconds
711 Delay before automatically booting the default image;
712 set to -1 to disable autoboot.
713 set to -2 to autoboot with no delay and not check for abort
714 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
716 See doc/README.autoboot for these options that
717 work with CONFIG_BOOTDELAY. None are required.
718 CONFIG_BOOT_RETRY_TIME
719 CONFIG_BOOT_RETRY_MIN
720 CONFIG_AUTOBOOT_KEYED
721 CONFIG_AUTOBOOT_PROMPT
722 CONFIG_AUTOBOOT_DELAY_STR
723 CONFIG_AUTOBOOT_STOP_STR
724 CONFIG_AUTOBOOT_DELAY_STR2
725 CONFIG_AUTOBOOT_STOP_STR2
726 CONFIG_ZERO_BOOTDELAY_CHECK
727 CONFIG_RESET_TO_RETRY
731 Only needed when CONFIG_BOOTDELAY is enabled;
732 define a command string that is automatically executed
733 when no character is read on the console interface
734 within "Boot Delay" after reset.
737 This can be used to pass arguments to the bootm
738 command. The value of CONFIG_BOOTARGS goes into the
739 environment value "bootargs".
741 CONFIG_RAMBOOT and CONFIG_NFSBOOT
742 The value of these goes into the environment as
743 "ramboot" and "nfsboot" respectively, and can be used
744 as a convenience, when switching between booting from
750 When this option is #defined, the existence of the
751 environment variable "preboot" will be checked
752 immediately before starting the CONFIG_BOOTDELAY
753 countdown and/or running the auto-boot command resp.
754 entering interactive mode.
756 This feature is especially useful when "preboot" is
757 automatically generated or modified. For an example
758 see the LWMON board specific code: here "preboot" is
759 modified when the user holds down a certain
760 combination of keys on the (special) keyboard when
763 - Serial Download Echo Mode:
765 If defined to 1, all characters received during a
766 serial download (using the "loads" command) are
767 echoed back. This might be needed by some terminal
768 emulations (like "cu"), but may as well just take
769 time on others. This setting #define's the initial
770 value of the "loads_echo" environment variable.
772 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
774 Select one of the baudrates listed in
775 CONFIG_SYS_BAUDRATE_TABLE, see below.
778 Monitor commands can be included or excluded
779 from the build by using the #include files
780 <config_cmd_all.h> and #undef'ing unwanted
781 commands, or using <config_cmd_default.h>
782 and augmenting with additional #define's
785 The default command configuration includes all commands
786 except those marked below with a "*".
788 CONFIG_CMD_ASKENV * ask for env variable
789 CONFIG_CMD_BDI bdinfo
790 CONFIG_CMD_BEDBUG * Include BedBug Debugger
791 CONFIG_CMD_BMP * BMP support
792 CONFIG_CMD_BSP * Board specific commands
793 CONFIG_CMD_BOOTD bootd
794 CONFIG_CMD_CACHE * icache, dcache
795 CONFIG_CMD_CONSOLE coninfo
796 CONFIG_CMD_CRC32 * crc32
797 CONFIG_CMD_DATE * support for RTC, date/time...
798 CONFIG_CMD_DHCP * DHCP support
799 CONFIG_CMD_DIAG * Diagnostics
800 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
801 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
802 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
803 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
804 CONFIG_CMD_DTT * Digital Therm and Thermostat
805 CONFIG_CMD_ECHO echo arguments
806 CONFIG_CMD_EDITENV edit env variable
807 CONFIG_CMD_EEPROM * EEPROM read/write support
808 CONFIG_CMD_ELF * bootelf, bootvx
809 CONFIG_CMD_EXPORTENV * export the environment
810 CONFIG_CMD_SAVEENV saveenv
811 CONFIG_CMD_FDC * Floppy Disk Support
812 CONFIG_CMD_FAT * FAT partition support
813 CONFIG_CMD_FDOS * Dos diskette Support
814 CONFIG_CMD_FLASH flinfo, erase, protect
815 CONFIG_CMD_FPGA FPGA device initialization support
816 CONFIG_CMD_GO * the 'go' command (exec code)
817 CONFIG_CMD_GREPENV * search environment
818 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
819 CONFIG_CMD_I2C * I2C serial bus support
820 CONFIG_CMD_IDE * IDE harddisk support
821 CONFIG_CMD_IMI iminfo
822 CONFIG_CMD_IMLS List all found images
823 CONFIG_CMD_IMMAP * IMMR dump support
824 CONFIG_CMD_IMPORTENV * import an environment
825 CONFIG_CMD_INI * import data from an ini file into the env
826 CONFIG_CMD_IRQ * irqinfo
827 CONFIG_CMD_ITEST Integer/string test of 2 values
828 CONFIG_CMD_JFFS2 * JFFS2 Support
829 CONFIG_CMD_KGDB * kgdb
830 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
831 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
833 CONFIG_CMD_LOADB loadb
834 CONFIG_CMD_LOADS loads
835 CONFIG_CMD_MD5SUM print md5 message digest
836 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
837 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
839 CONFIG_CMD_MISC Misc functions like sleep etc
840 CONFIG_CMD_MMC * MMC memory mapped support
841 CONFIG_CMD_MII * MII utility commands
842 CONFIG_CMD_MTDPARTS * MTD partition support
843 CONFIG_CMD_NAND * NAND support
844 CONFIG_CMD_NET bootp, tftpboot, rarpboot
845 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
846 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
847 CONFIG_CMD_PCI * pciinfo
848 CONFIG_CMD_PCMCIA * PCMCIA support
849 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
851 CONFIG_CMD_PORTIO * Port I/O
852 CONFIG_CMD_REGINFO * Register dump
853 CONFIG_CMD_RUN run command in env variable
854 CONFIG_CMD_SAVES * save S record dump
855 CONFIG_CMD_SCSI * SCSI Support
856 CONFIG_CMD_SDRAM * print SDRAM configuration information
857 (requires CONFIG_CMD_I2C)
858 CONFIG_CMD_SETGETDCR Support for DCR Register access
860 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
861 CONFIG_CMD_SHA1SUM print sha1 memory digest
862 (requires CONFIG_CMD_MEMORY)
863 CONFIG_CMD_SOURCE "source" command Support
864 CONFIG_CMD_SPI * SPI serial bus support
865 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
866 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
867 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
868 CONFIG_CMD_TIMER * access to the system tick timer
869 CONFIG_CMD_USB * USB support
870 CONFIG_CMD_CDP * Cisco Discover Protocol support
871 CONFIG_CMD_MFSL * Microblaze FSL support
874 EXAMPLE: If you want all functions except of network
875 support you can write:
877 #include "config_cmd_all.h"
878 #undef CONFIG_CMD_NET
881 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
883 Note: Don't enable the "icache" and "dcache" commands
884 (configuration option CONFIG_CMD_CACHE) unless you know
885 what you (and your U-Boot users) are doing. Data
886 cache cannot be enabled on systems like the 8xx or
887 8260 (where accesses to the IMMR region must be
888 uncached), and it cannot be disabled on all other
889 systems where we (mis-) use the data cache to hold an
890 initial stack and some data.
893 XXX - this list needs to get updated!
897 If this variable is defined, U-Boot will use a device tree
898 to configure its devices, instead of relying on statically
899 compiled #defines in the board file. This option is
900 experimental and only available on a few boards. The device
901 tree is available in the global data as gd->fdt_blob.
903 U-Boot needs to get its device tree from somewhere. This can
904 be done using one of the two options below:
907 If this variable is defined, U-Boot will embed a device tree
908 binary in its image. This device tree file should be in the
909 board directory and called <soc>-<board>.dts. The binary file
910 is then picked up in board_init_f() and made available through
911 the global data structure as gd->blob.
914 If this variable is defined, U-Boot will build a device tree
915 binary. It will be called u-boot.dtb. Architecture-specific
916 code will locate it at run-time. Generally this works by:
918 cat u-boot.bin u-boot.dtb >image.bin
920 and in fact, U-Boot does this for you, creating a file called
921 u-boot-dtb.bin which is useful in the common case. You can
922 still use the individual files if you need something more
927 If this variable is defined, it enables watchdog
928 support for the SoC. There must be support in the SoC
929 specific code for a watchdog. For the 8xx and 8260
930 CPUs, the SIU Watchdog feature is enabled in the SYPCR
931 register. When supported for a specific SoC is
932 available, then no further board specific code should
936 When using a watchdog circuitry external to the used
937 SoC, then define this variable and provide board
938 specific code for the "hw_watchdog_reset" function.
941 CONFIG_VERSION_VARIABLE
942 If this variable is defined, an environment variable
943 named "ver" is created by U-Boot showing the U-Boot
944 version as printed by the "version" command.
945 Any change to this variable will be reverted at the
950 When CONFIG_CMD_DATE is selected, the type of the RTC
951 has to be selected, too. Define exactly one of the
954 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
955 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
956 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
957 CONFIG_RTC_MC146818 - use MC146818 RTC
958 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
959 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
960 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
961 CONFIG_RTC_DS164x - use Dallas DS164x RTC
962 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
963 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
964 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
965 CONFIG_SYS_RV3029_TCR - enable trickle charger on
968 Note that if the RTC uses I2C, then the I2C interface
969 must also be configured. See I2C Support, below.
972 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
973 CONFIG_PCA953X_INFO - enable pca953x info command
975 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
976 chip-ngpio pairs that tell the PCA953X driver the number of
977 pins supported by a particular chip.
979 Note that if the GPIO device uses I2C, then the I2C interface
980 must also be configured. See I2C Support, below.
984 When CONFIG_TIMESTAMP is selected, the timestamp
985 (date and time) of an image is printed by image
986 commands like bootm or iminfo. This option is
987 automatically enabled when you select CONFIG_CMD_DATE .
989 - Partition Labels (disklabels) Supported:
990 Zero or more of the following:
991 CONFIG_MAC_PARTITION Apple's MacOS partition table.
992 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
993 Intel architecture, USB sticks, etc.
994 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
995 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
996 bootloader. Note 2TB partition limit; see
998 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1000 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1001 CONFIG_CMD_SCSI) you must configure support for at
1002 least one non-MTD partition type as well.
1005 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1006 board configurations files but used nowhere!
1008 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1009 be performed by calling the function
1010 ide_set_reset(int reset)
1011 which has to be defined in a board specific file
1016 Set this to enable ATAPI support.
1021 Set this to enable support for disks larger than 137GB
1022 Also look at CONFIG_SYS_64BIT_LBA.
1023 Whithout these , LBA48 support uses 32bit variables and will 'only'
1024 support disks up to 2.1TB.
1026 CONFIG_SYS_64BIT_LBA:
1027 When enabled, makes the IDE subsystem use 64bit sector addresses.
1031 At the moment only there is only support for the
1032 SYM53C8XX SCSI controller; define
1033 CONFIG_SCSI_SYM53C8XX to enable it.
1035 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1036 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1037 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1038 maximum numbers of LUNs, SCSI ID's and target
1040 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1042 - NETWORK Support (PCI):
1044 Support for Intel 8254x/8257x gigabit chips.
1047 Utility code for direct access to the SPI bus on Intel 8257x.
1048 This does not do anything useful unless you set at least one
1049 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1051 CONFIG_E1000_SPI_GENERIC
1052 Allow generic access to the SPI bus on the Intel 8257x, for
1053 example with the "sspi" command.
1056 Management command for E1000 devices. When used on devices
1057 with SPI support you can reprogram the EEPROM from U-Boot.
1059 CONFIG_E1000_FALLBACK_MAC
1060 default MAC for empty EEPROM after production.
1063 Support for Intel 82557/82559/82559ER chips.
1064 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1065 write routine for first time initialisation.
1068 Support for Digital 2114x chips.
1069 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1070 modem chip initialisation (KS8761/QS6611).
1073 Support for National dp83815 chips.
1076 Support for National dp8382[01] gigabit chips.
1078 - NETWORK Support (other):
1080 CONFIG_DRIVER_AT91EMAC
1081 Support for AT91RM9200 EMAC.
1084 Define this to use reduced MII inteface
1086 CONFIG_DRIVER_AT91EMAC_QUIET
1087 If this defined, the driver is quiet.
1088 The driver doen't show link status messages.
1090 CONFIG_CALXEDA_XGMAC
1091 Support for the Calxeda XGMAC device
1093 CONFIG_DRIVER_LAN91C96
1094 Support for SMSC's LAN91C96 chips.
1096 CONFIG_LAN91C96_BASE
1097 Define this to hold the physical address
1098 of the LAN91C96's I/O space
1100 CONFIG_LAN91C96_USE_32_BIT
1101 Define this to enable 32 bit addressing
1103 CONFIG_DRIVER_SMC91111
1104 Support for SMSC's LAN91C111 chip
1106 CONFIG_SMC91111_BASE
1107 Define this to hold the physical address
1108 of the device (I/O space)
1110 CONFIG_SMC_USE_32_BIT
1111 Define this if data bus is 32 bits
1113 CONFIG_SMC_USE_IOFUNCS
1114 Define this to use i/o functions instead of macros
1115 (some hardware wont work with macros)
1117 CONFIG_DRIVER_TI_EMAC
1118 Support for davinci emac
1120 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1121 Define this if you have more then 3 PHYs.
1124 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1126 CONFIG_FTGMAC100_EGIGA
1127 Define this to use GE link update with gigabit PHY.
1128 Define this if FTGMAC100 is connected to gigabit PHY.
1129 If your system has 10/100 PHY only, it might not occur
1130 wrong behavior. Because PHY usually return timeout or
1131 useless data when polling gigabit status and gigabit
1132 control registers. This behavior won't affect the
1133 correctnessof 10/100 link speed update.
1136 Support for SMSC's LAN911x and LAN921x chips
1139 Define this to hold the physical address
1140 of the device (I/O space)
1142 CONFIG_SMC911X_32_BIT
1143 Define this if data bus is 32 bits
1145 CONFIG_SMC911X_16_BIT
1146 Define this if data bus is 16 bits. If your processor
1147 automatically converts one 32 bit word to two 16 bit
1148 words you may also try CONFIG_SMC911X_32_BIT.
1151 Support for Renesas on-chip Ethernet controller
1153 CONFIG_SH_ETHER_USE_PORT
1154 Define the number of ports to be used
1156 CONFIG_SH_ETHER_PHY_ADDR
1157 Define the ETH PHY's address
1159 CONFIG_SH_ETHER_CACHE_WRITEBACK
1160 If this option is set, the driver enables cache flush.
1163 CONFIG_GENERIC_LPC_TPM
1164 Support for generic parallel port TPM devices. Only one device
1165 per system is supported at this time.
1167 CONFIG_TPM_TIS_BASE_ADDRESS
1168 Base address where the generic TPM device is mapped
1169 to. Contemporary x86 systems usually map it at
1173 At the moment only the UHCI host controller is
1174 supported (PIP405, MIP405, MPC5200); define
1175 CONFIG_USB_UHCI to enable it.
1176 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1177 and define CONFIG_USB_STORAGE to enable the USB
1180 Supported are USB Keyboards and USB Floppy drives
1182 MPC5200 USB requires additional defines:
1184 for 528 MHz Clock: 0x0001bbbb
1188 for differential drivers: 0x00001000
1189 for single ended drivers: 0x00005000
1190 for differential drivers on PSC3: 0x00000100
1191 for single ended drivers on PSC3: 0x00004100
1192 CONFIG_SYS_USB_EVENT_POLL
1193 May be defined to allow interrupt polling
1194 instead of using asynchronous interrupts
1196 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1197 txfilltuning field in the EHCI controller on reset.
1200 Define the below if you wish to use the USB console.
1201 Once firmware is rebuilt from a serial console issue the
1202 command "setenv stdin usbtty; setenv stdout usbtty" and
1203 attach your USB cable. The Unix command "dmesg" should print
1204 it has found a new device. The environment variable usbtty
1205 can be set to gserial or cdc_acm to enable your device to
1206 appear to a USB host as a Linux gserial device or a
1207 Common Device Class Abstract Control Model serial device.
1208 If you select usbtty = gserial you should be able to enumerate
1210 # modprobe usbserial vendor=0xVendorID product=0xProductID
1211 else if using cdc_acm, simply setting the environment
1212 variable usbtty to be cdc_acm should suffice. The following
1213 might be defined in YourBoardName.h
1216 Define this to build a UDC device
1219 Define this to have a tty type of device available to
1220 talk to the UDC device
1223 Define this to enable the high speed support for usb
1224 device and usbtty. If this feature is enabled, a routine
1225 int is_usbd_high_speed(void)
1226 also needs to be defined by the driver to dynamically poll
1227 whether the enumeration has succeded at high speed or full
1230 CONFIG_SYS_CONSOLE_IS_IN_ENV
1231 Define this if you want stdin, stdout &/or stderr to
1235 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1236 Derive USB clock from external clock "blah"
1237 - CONFIG_SYS_USB_EXTC_CLK 0x02
1239 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1240 Derive USB clock from brgclk
1241 - CONFIG_SYS_USB_BRG_CLK 0x04
1243 If you have a USB-IF assigned VendorID then you may wish to
1244 define your own vendor specific values either in BoardName.h
1245 or directly in usbd_vendor_info.h. If you don't define
1246 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1247 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1248 should pretend to be a Linux device to it's target host.
1250 CONFIG_USBD_MANUFACTURER
1251 Define this string as the name of your company for
1252 - CONFIG_USBD_MANUFACTURER "my company"
1254 CONFIG_USBD_PRODUCT_NAME
1255 Define this string as the name of your product
1256 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1258 CONFIG_USBD_VENDORID
1259 Define this as your assigned Vendor ID from the USB
1260 Implementors Forum. This *must* be a genuine Vendor ID
1261 to avoid polluting the USB namespace.
1262 - CONFIG_USBD_VENDORID 0xFFFF
1264 CONFIG_USBD_PRODUCTID
1265 Define this as the unique Product ID
1267 - CONFIG_USBD_PRODUCTID 0xFFFF
1269 - ULPI Layer Support:
1270 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1271 the generic ULPI layer. The generic layer accesses the ULPI PHY
1272 via the platform viewport, so you need both the genric layer and
1273 the viewport enabled. Currently only Chipidea/ARC based
1274 viewport is supported.
1275 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1276 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1277 If your ULPI phy needs a different reference clock than the
1278 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1279 the appropriate value in Hz.
1282 The MMC controller on the Intel PXA is supported. To
1283 enable this define CONFIG_MMC. The MMC can be
1284 accessed from the boot prompt by mapping the device
1285 to physical memory similar to flash. Command line is
1286 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1287 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1290 Support for Renesas on-chip MMCIF controller
1292 CONFIG_SH_MMCIF_ADDR
1293 Define the base address of MMCIF registers
1296 Define the clock frequency for MMCIF
1298 - Journaling Flash filesystem support:
1299 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1300 CONFIG_JFFS2_NAND_DEV
1301 Define these for a default partition on a NAND device
1303 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1304 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1305 Define these for a default partition on a NOR device
1307 CONFIG_SYS_JFFS_CUSTOM_PART
1308 Define this to create an own partition. You have to provide a
1309 function struct part_info* jffs2_part_info(int part_num)
1311 If you define only one JFFS2 partition you may also want to
1312 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1313 to disable the command chpart. This is the default when you
1314 have not defined a custom partition
1316 - FAT(File Allocation Table) filesystem write function support:
1319 Define this to enable support for saving memory data as a
1320 file in FAT formatted partition.
1322 This will also enable the command "fatwrite" enabling the
1323 user to write files to FAT.
1328 Define this to enable standard (PC-Style) keyboard
1332 Standard PC keyboard driver with US (is default) and
1333 GERMAN key layout (switch via environment 'keymap=de') support.
1334 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1335 for cfb_console. Supports cursor blinking.
1340 Define this to enable video support (for output to
1343 CONFIG_VIDEO_CT69000
1345 Enable Chips & Technologies 69000 Video chip
1347 CONFIG_VIDEO_SMI_LYNXEM
1348 Enable Silicon Motion SMI 712/710/810 Video chip. The
1349 video output is selected via environment 'videoout'
1350 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1353 For the CT69000 and SMI_LYNXEM drivers, videomode is
1354 selected via environment 'videomode'. Two different ways
1356 - "videomode=num" 'num' is a standard LiLo mode numbers.
1357 Following standard modes are supported (* is default):
1359 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1360 -------------+---------------------------------------------
1361 8 bits | 0x301* 0x303 0x305 0x161 0x307
1362 15 bits | 0x310 0x313 0x316 0x162 0x319
1363 16 bits | 0x311 0x314 0x317 0x163 0x31A
1364 24 bits | 0x312 0x315 0x318 ? 0x31B
1365 -------------+---------------------------------------------
1366 (i.e. setenv videomode 317; saveenv; reset;)
1368 - "videomode=bootargs" all the video parameters are parsed
1369 from the bootargs. (See drivers/video/videomodes.c)
1372 CONFIG_VIDEO_SED13806
1373 Enable Epson SED13806 driver. This driver supports 8bpp
1374 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1375 or CONFIG_VIDEO_SED13806_16BPP
1378 Enable the Freescale DIU video driver. Reference boards for
1379 SOCs that have a DIU should define this macro to enable DIU
1380 support, and should also define these other macros:
1386 CONFIG_VIDEO_SW_CURSOR
1387 CONFIG_VGA_AS_SINGLE_DEVICE
1389 CONFIG_VIDEO_BMP_LOGO
1391 The DIU driver will look for the 'video-mode' environment
1392 variable, and if defined, enable the DIU as a console during
1393 boot. See the documentation file README.video for a
1394 description of this variable.
1399 Define this to enable a custom keyboard support.
1400 This simply calls drv_keyboard_init() which must be
1401 defined in your board-specific files.
1402 The only board using this so far is RBC823.
1404 - LCD Support: CONFIG_LCD
1406 Define this to enable LCD support (for output to LCD
1407 display); also select one of the supported displays
1408 by defining one of these:
1412 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1414 CONFIG_NEC_NL6448AC33:
1416 NEC NL6448AC33-18. Active, color, single scan.
1418 CONFIG_NEC_NL6448BC20
1420 NEC NL6448BC20-08. 6.5", 640x480.
1421 Active, color, single scan.
1423 CONFIG_NEC_NL6448BC33_54
1425 NEC NL6448BC33-54. 10.4", 640x480.
1426 Active, color, single scan.
1430 Sharp 320x240. Active, color, single scan.
1431 It isn't 16x9, and I am not sure what it is.
1433 CONFIG_SHARP_LQ64D341
1435 Sharp LQ64D341 display, 640x480.
1436 Active, color, single scan.
1440 HLD1045 display, 640x480.
1441 Active, color, single scan.
1445 Optrex CBL50840-2 NF-FW 99 22 M5
1447 Hitachi LMG6912RPFC-00T
1451 320x240. Black & white.
1453 Normally display is black on white background; define
1454 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1456 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1458 If this option is set, the environment is checked for
1459 a variable "splashimage". If found, the usual display
1460 of logo, copyright and system information on the LCD
1461 is suppressed and the BMP image at the address
1462 specified in "splashimage" is loaded instead. The
1463 console is redirected to the "nulldev", too. This
1464 allows for a "silent" boot where a splash screen is
1465 loaded very quickly after power-on.
1467 CONFIG_SPLASH_SCREEN_ALIGN
1469 If this option is set the splash image can be freely positioned
1470 on the screen. Environment variable "splashpos" specifies the
1471 position as "x,y". If a positive number is given it is used as
1472 number of pixel from left/top. If a negative number is given it
1473 is used as number of pixel from right/bottom. You can also
1474 specify 'm' for centering the image.
1477 setenv splashpos m,m
1478 => image at center of screen
1480 setenv splashpos 30,20
1481 => image at x = 30 and y = 20
1483 setenv splashpos -10,m
1484 => vertically centered image
1485 at x = dspWidth - bmpWidth - 9
1487 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1489 If this option is set, additionally to standard BMP
1490 images, gzipped BMP images can be displayed via the
1491 splashscreen support or the bmp command.
1493 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1495 If this option is set, 8-bit RLE compressed BMP images
1496 can be displayed via the splashscreen support or the
1499 - Do compresssing for memory range:
1502 If this option is set, it would use zlib deflate method
1503 to compress the specified memory at its best effort.
1505 - Compression support:
1508 If this option is set, support for bzip2 compressed
1509 images is included. If not, only uncompressed and gzip
1510 compressed images are supported.
1512 NOTE: the bzip2 algorithm requires a lot of RAM, so
1513 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1518 If this option is set, support for lzma compressed
1521 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1522 requires an amount of dynamic memory that is given by the
1525 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1527 Where lc and lp stand for, respectively, Literal context bits
1528 and Literal pos bits.
1530 This value is upper-bounded by 14MB in the worst case. Anyway,
1531 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1532 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1533 a very small buffer.
1535 Use the lzmainfo tool to determinate the lc and lp values and
1536 then calculate the amount of needed dynamic memory (ensuring
1537 the appropriate CONFIG_SYS_MALLOC_LEN value).
1542 The address of PHY on MII bus.
1544 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1546 The clock frequency of the MII bus
1550 If this option is set, support for speed/duplex
1551 detection of gigabit PHY is included.
1553 CONFIG_PHY_RESET_DELAY
1555 Some PHY like Intel LXT971A need extra delay after
1556 reset before any MII register access is possible.
1557 For such PHY, set this option to the usec delay
1558 required. (minimum 300usec for LXT971A)
1560 CONFIG_PHY_CMD_DELAY (ppc4xx)
1562 Some PHY like Intel LXT971A need extra delay after
1563 command issued before MII status register can be read
1573 Define a default value for Ethernet address to use
1574 for the respective Ethernet interface, in case this
1575 is not determined automatically.
1580 Define a default value for the IP address to use for
1581 the default Ethernet interface, in case this is not
1582 determined through e.g. bootp.
1583 (Environment variable "ipaddr")
1585 - Server IP address:
1588 Defines a default value for the IP address of a TFTP
1589 server to contact when using the "tftboot" command.
1590 (Environment variable "serverip")
1592 CONFIG_KEEP_SERVERADDR
1594 Keeps the server's MAC address, in the env 'serveraddr'
1595 for passing to bootargs (like Linux's netconsole option)
1597 - Gateway IP address:
1600 Defines a default value for the IP address of the
1601 default router where packets to other networks are
1603 (Environment variable "gatewayip")
1608 Defines a default value for the subnet mask (or
1609 routing prefix) which is used to determine if an IP
1610 address belongs to the local subnet or needs to be
1611 forwarded through a router.
1612 (Environment variable "netmask")
1614 - Multicast TFTP Mode:
1617 Defines whether you want to support multicast TFTP as per
1618 rfc-2090; for example to work with atftp. Lets lots of targets
1619 tftp down the same boot image concurrently. Note: the Ethernet
1620 driver in use must provide a function: mcast() to join/leave a
1623 - BOOTP Recovery Mode:
1624 CONFIG_BOOTP_RANDOM_DELAY
1626 If you have many targets in a network that try to
1627 boot using BOOTP, you may want to avoid that all
1628 systems send out BOOTP requests at precisely the same
1629 moment (which would happen for instance at recovery
1630 from a power failure, when all systems will try to
1631 boot, thus flooding the BOOTP server. Defining
1632 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1633 inserted before sending out BOOTP requests. The
1634 following delays are inserted then:
1636 1st BOOTP request: delay 0 ... 1 sec
1637 2nd BOOTP request: delay 0 ... 2 sec
1638 3rd BOOTP request: delay 0 ... 4 sec
1640 BOOTP requests: delay 0 ... 8 sec
1642 - DHCP Advanced Options:
1643 You can fine tune the DHCP functionality by defining
1644 CONFIG_BOOTP_* symbols:
1646 CONFIG_BOOTP_SUBNETMASK
1647 CONFIG_BOOTP_GATEWAY
1648 CONFIG_BOOTP_HOSTNAME
1649 CONFIG_BOOTP_NISDOMAIN
1650 CONFIG_BOOTP_BOOTPATH
1651 CONFIG_BOOTP_BOOTFILESIZE
1654 CONFIG_BOOTP_SEND_HOSTNAME
1655 CONFIG_BOOTP_NTPSERVER
1656 CONFIG_BOOTP_TIMEOFFSET
1657 CONFIG_BOOTP_VENDOREX
1658 CONFIG_BOOTP_MAY_FAIL
1660 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1661 environment variable, not the BOOTP server.
1663 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1664 after the configured retry count, the call will fail
1665 instead of starting over. This can be used to fail over
1666 to Link-local IP address configuration if the DHCP server
1669 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1670 serverip from a DHCP server, it is possible that more
1671 than one DNS serverip is offered to the client.
1672 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1673 serverip will be stored in the additional environment
1674 variable "dnsip2". The first DNS serverip is always
1675 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1678 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1679 to do a dynamic update of a DNS server. To do this, they
1680 need the hostname of the DHCP requester.
1681 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1682 of the "hostname" environment variable is passed as
1683 option 12 to the DHCP server.
1685 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1687 A 32bit value in microseconds for a delay between
1688 receiving a "DHCP Offer" and sending the "DHCP Request".
1689 This fixes a problem with certain DHCP servers that don't
1690 respond 100% of the time to a "DHCP request". E.g. On an
1691 AT91RM9200 processor running at 180MHz, this delay needed
1692 to be *at least* 15,000 usec before a Windows Server 2003
1693 DHCP server would reply 100% of the time. I recommend at
1694 least 50,000 usec to be safe. The alternative is to hope
1695 that one of the retries will be successful but note that
1696 the DHCP timeout and retry process takes a longer than
1699 - Link-local IP address negotiation:
1700 Negotiate with other link-local clients on the local network
1701 for an address that doesn't require explicit configuration.
1702 This is especially useful if a DHCP server cannot be guaranteed
1703 to exist in all environments that the device must operate.
1705 See doc/README.link-local for more information.
1708 CONFIG_CDP_DEVICE_ID
1710 The device id used in CDP trigger frames.
1712 CONFIG_CDP_DEVICE_ID_PREFIX
1714 A two character string which is prefixed to the MAC address
1719 A printf format string which contains the ascii name of
1720 the port. Normally is set to "eth%d" which sets
1721 eth0 for the first Ethernet, eth1 for the second etc.
1723 CONFIG_CDP_CAPABILITIES
1725 A 32bit integer which indicates the device capabilities;
1726 0x00000010 for a normal host which does not forwards.
1730 An ascii string containing the version of the software.
1734 An ascii string containing the name of the platform.
1738 A 32bit integer sent on the trigger.
1740 CONFIG_CDP_POWER_CONSUMPTION
1742 A 16bit integer containing the power consumption of the
1743 device in .1 of milliwatts.
1745 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1747 A byte containing the id of the VLAN.
1749 - Status LED: CONFIG_STATUS_LED
1751 Several configurations allow to display the current
1752 status using a LED. For instance, the LED will blink
1753 fast while running U-Boot code, stop blinking as
1754 soon as a reply to a BOOTP request was received, and
1755 start blinking slow once the Linux kernel is running
1756 (supported by a status LED driver in the Linux
1757 kernel). Defining CONFIG_STATUS_LED enables this
1760 - CAN Support: CONFIG_CAN_DRIVER
1762 Defining CONFIG_CAN_DRIVER enables CAN driver support
1763 on those systems that support this (optional)
1764 feature, like the TQM8xxL modules.
1766 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1768 These enable I2C serial bus commands. Defining either of
1769 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1770 include the appropriate I2C driver for the selected CPU.
1772 This will allow you to use i2c commands at the u-boot
1773 command line (as long as you set CONFIG_CMD_I2C in
1774 CONFIG_COMMANDS) and communicate with i2c based realtime
1775 clock chips. See common/cmd_i2c.c for a description of the
1776 command line interface.
1778 CONFIG_HARD_I2C selects a hardware I2C controller.
1780 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1781 bit-banging) driver instead of CPM or similar hardware
1784 There are several other quantities that must also be
1785 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1787 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1788 to be the frequency (in Hz) at which you wish your i2c bus
1789 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1790 the CPU's i2c node address).
1792 Now, the u-boot i2c code for the mpc8xx
1793 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1794 and so its address should therefore be cleared to 0 (See,
1795 eg, MPC823e User's Manual p.16-473). So, set
1796 CONFIG_SYS_I2C_SLAVE to 0.
1798 CONFIG_SYS_I2C_INIT_MPC5XXX
1800 When a board is reset during an i2c bus transfer
1801 chips might think that the current transfer is still
1802 in progress. Reset the slave devices by sending start
1803 commands until the slave device responds.
1805 That's all that's required for CONFIG_HARD_I2C.
1807 If you use the software i2c interface (CONFIG_SOFT_I2C)
1808 then the following macros need to be defined (examples are
1809 from include/configs/lwmon.h):
1813 (Optional). Any commands necessary to enable the I2C
1814 controller or configure ports.
1816 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1820 (Only for MPC8260 CPU). The I/O port to use (the code
1821 assumes both bits are on the same port). Valid values
1822 are 0..3 for ports A..D.
1826 The code necessary to make the I2C data line active
1827 (driven). If the data line is open collector, this
1830 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1834 The code necessary to make the I2C data line tri-stated
1835 (inactive). If the data line is open collector, this
1838 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1842 Code that returns TRUE if the I2C data line is high,
1845 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1849 If <bit> is TRUE, sets the I2C data line high. If it
1850 is FALSE, it clears it (low).
1852 eg: #define I2C_SDA(bit) \
1853 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1854 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1858 If <bit> is TRUE, sets the I2C clock line high. If it
1859 is FALSE, it clears it (low).
1861 eg: #define I2C_SCL(bit) \
1862 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1863 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1867 This delay is invoked four times per clock cycle so this
1868 controls the rate of data transfer. The data rate thus
1869 is 1 / (I2C_DELAY * 4). Often defined to be something
1872 #define I2C_DELAY udelay(2)
1874 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1876 If your arch supports the generic GPIO framework (asm/gpio.h),
1877 then you may alternatively define the two GPIOs that are to be
1878 used as SCL / SDA. Any of the previous I2C_xxx macros will
1879 have GPIO-based defaults assigned to them as appropriate.
1881 You should define these to the GPIO value as given directly to
1882 the generic GPIO functions.
1884 CONFIG_SYS_I2C_INIT_BOARD
1886 When a board is reset during an i2c bus transfer
1887 chips might think that the current transfer is still
1888 in progress. On some boards it is possible to access
1889 the i2c SCLK line directly, either by using the
1890 processor pin as a GPIO or by having a second pin
1891 connected to the bus. If this option is defined a
1892 custom i2c_init_board() routine in boards/xxx/board.c
1893 is run early in the boot sequence.
1895 CONFIG_SYS_I2C_BOARD_LATE_INIT
1897 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1898 defined a custom i2c_board_late_init() routine in
1899 boards/xxx/board.c is run AFTER the operations in i2c_init()
1900 is completed. This callpoint can be used to unreset i2c bus
1901 using CPU i2c controller register accesses for CPUs whose i2c
1902 controller provide such a method. It is called at the end of
1903 i2c_init() to allow i2c_init operations to setup the i2c bus
1904 controller on the CPU (e.g. setting bus speed & slave address).
1906 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1908 This option enables configuration of bi_iic_fast[] flags
1909 in u-boot bd_info structure based on u-boot environment
1910 variable "i2cfast". (see also i2cfast)
1912 CONFIG_I2C_MULTI_BUS
1914 This option allows the use of multiple I2C buses, each of which
1915 must have a controller. At any point in time, only one bus is
1916 active. To switch to a different bus, use the 'i2c dev' command.
1917 Note that bus numbering is zero-based.
1919 CONFIG_SYS_I2C_NOPROBES
1921 This option specifies a list of I2C devices that will be skipped
1922 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1923 is set, specify a list of bus-device pairs. Otherwise, specify
1924 a 1D array of device addresses
1927 #undef CONFIG_I2C_MULTI_BUS
1928 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1930 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1932 #define CONFIG_I2C_MULTI_BUS
1933 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1935 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1937 CONFIG_SYS_SPD_BUS_NUM
1939 If defined, then this indicates the I2C bus number for DDR SPD.
1940 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1942 CONFIG_SYS_RTC_BUS_NUM
1944 If defined, then this indicates the I2C bus number for the RTC.
1945 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1947 CONFIG_SYS_DTT_BUS_NUM
1949 If defined, then this indicates the I2C bus number for the DTT.
1950 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1952 CONFIG_SYS_I2C_DTT_ADDR:
1954 If defined, specifies the I2C address of the DTT device.
1955 If not defined, then U-Boot uses predefined value for
1956 specified DTT device.
1960 Define this option if you want to use Freescale's I2C driver in
1961 drivers/i2c/fsl_i2c.c.
1965 Define this option if you have I2C devices reached over 1 .. n
1966 I2C Muxes like the pca9544a. This option addes a new I2C
1967 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1968 new I2C Bus to the existing I2C Busses. If you select the
1969 new Bus with "i2c dev", u-bbot sends first the commandos for
1970 the muxes to activate this new "bus".
1972 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1976 Adding a new I2C Bus reached over 2 pca9544a muxes
1977 The First mux with address 70 and channel 6
1978 The Second mux with address 71 and channel 4
1980 => i2c bus pca9544a:70:6:pca9544a:71:4
1982 Use the "i2c bus" command without parameter, to get a list
1983 of I2C Busses with muxes:
1986 Busses reached over muxes:
1988 reached over Mux(es):
1991 reached over Mux(es):
1996 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1997 u-boot first sends the command to the mux@70 to enable
1998 channel 6, and then the command to the mux@71 to enable
2001 After that, you can use the "normal" i2c commands as
2002 usual to communicate with your I2C devices behind
2005 This option is actually implemented for the bitbanging
2006 algorithm in common/soft_i2c.c and for the Hardware I2C
2007 Bus on the MPC8260. But it should be not so difficult
2008 to add this option to other architectures.
2010 CONFIG_SOFT_I2C_READ_REPEATED_START
2012 defining this will force the i2c_read() function in
2013 the soft_i2c driver to perform an I2C repeated start
2014 between writing the address pointer and reading the
2015 data. If this define is omitted the default behaviour
2016 of doing a stop-start sequence will be used. Most I2C
2017 devices can use either method, but some require one or
2020 - SPI Support: CONFIG_SPI
2022 Enables SPI driver (so far only tested with
2023 SPI EEPROM, also an instance works with Crystal A/D and
2024 D/As on the SACSng board)
2028 Enables the driver for SPI controller on SuperH. Currently
2029 only SH7757 is supported.
2033 Enables extended (16-bit) SPI EEPROM addressing.
2034 (symmetrical to CONFIG_I2C_X)
2038 Enables a software (bit-bang) SPI driver rather than
2039 using hardware support. This is a general purpose
2040 driver that only requires three general I/O port pins
2041 (two outputs, one input) to function. If this is
2042 defined, the board configuration must define several
2043 SPI configuration items (port pins to use, etc). For
2044 an example, see include/configs/sacsng.h.
2048 Enables a hardware SPI driver for general-purpose reads
2049 and writes. As with CONFIG_SOFT_SPI, the board configuration
2050 must define a list of chip-select function pointers.
2051 Currently supported on some MPC8xxx processors. For an
2052 example, see include/configs/mpc8349emds.h.
2056 Enables the driver for the SPI controllers on i.MX and MXC
2057 SoCs. Currently i.MX31/35/51 are supported.
2059 - FPGA Support: CONFIG_FPGA
2061 Enables FPGA subsystem.
2063 CONFIG_FPGA_<vendor>
2065 Enables support for specific chip vendors.
2068 CONFIG_FPGA_<family>
2070 Enables support for FPGA family.
2071 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2075 Specify the number of FPGA devices to support.
2077 CONFIG_SYS_FPGA_PROG_FEEDBACK
2079 Enable printing of hash marks during FPGA configuration.
2081 CONFIG_SYS_FPGA_CHECK_BUSY
2083 Enable checks on FPGA configuration interface busy
2084 status by the configuration function. This option
2085 will require a board or device specific function to
2090 If defined, a function that provides delays in the FPGA
2091 configuration driver.
2093 CONFIG_SYS_FPGA_CHECK_CTRLC
2094 Allow Control-C to interrupt FPGA configuration
2096 CONFIG_SYS_FPGA_CHECK_ERROR
2098 Check for configuration errors during FPGA bitfile
2099 loading. For example, abort during Virtex II
2100 configuration if the INIT_B line goes low (which
2101 indicated a CRC error).
2103 CONFIG_SYS_FPGA_WAIT_INIT
2105 Maximum time to wait for the INIT_B line to deassert
2106 after PROB_B has been deasserted during a Virtex II
2107 FPGA configuration sequence. The default time is 500
2110 CONFIG_SYS_FPGA_WAIT_BUSY
2112 Maximum time to wait for BUSY to deassert during
2113 Virtex II FPGA configuration. The default is 5 ms.
2115 CONFIG_SYS_FPGA_WAIT_CONFIG
2117 Time to wait after FPGA configuration. The default is
2120 - Configuration Management:
2123 If defined, this string will be added to the U-Boot
2124 version information (U_BOOT_VERSION)
2126 - Vendor Parameter Protection:
2128 U-Boot considers the values of the environment
2129 variables "serial#" (Board Serial Number) and
2130 "ethaddr" (Ethernet Address) to be parameters that
2131 are set once by the board vendor / manufacturer, and
2132 protects these variables from casual modification by
2133 the user. Once set, these variables are read-only,
2134 and write or delete attempts are rejected. You can
2135 change this behaviour:
2137 If CONFIG_ENV_OVERWRITE is #defined in your config
2138 file, the write protection for vendor parameters is
2139 completely disabled. Anybody can change or delete
2142 Alternatively, if you #define _both_ CONFIG_ETHADDR
2143 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2144 Ethernet address is installed in the environment,
2145 which can be changed exactly ONCE by the user. [The
2146 serial# is unaffected by this, i. e. it remains
2152 Define this variable to enable the reservation of
2153 "protected RAM", i. e. RAM which is not overwritten
2154 by U-Boot. Define CONFIG_PRAM to hold the number of
2155 kB you want to reserve for pRAM. You can overwrite
2156 this default value by defining an environment
2157 variable "pram" to the number of kB you want to
2158 reserve. Note that the board info structure will
2159 still show the full amount of RAM. If pRAM is
2160 reserved, a new environment variable "mem" will
2161 automatically be defined to hold the amount of
2162 remaining RAM in a form that can be passed as boot
2163 argument to Linux, for instance like that:
2165 setenv bootargs ... mem=\${mem}
2168 This way you can tell Linux not to use this memory,
2169 either, which results in a memory region that will
2170 not be affected by reboots.
2172 *WARNING* If your board configuration uses automatic
2173 detection of the RAM size, you must make sure that
2174 this memory test is non-destructive. So far, the
2175 following board configurations are known to be
2178 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2179 HERMES, IP860, RPXlite, LWMON, LANTEC,
2185 Define this variable to stop the system in case of a
2186 fatal error, so that you have to reset it manually.
2187 This is probably NOT a good idea for an embedded
2188 system where you want the system to reboot
2189 automatically as fast as possible, but it may be
2190 useful during development since you can try to debug
2191 the conditions that lead to the situation.
2193 CONFIG_NET_RETRY_COUNT
2195 This variable defines the number of retries for
2196 network operations like ARP, RARP, TFTP, or BOOTP
2197 before giving up the operation. If not defined, a
2198 default value of 5 is used.
2202 Timeout waiting for an ARP reply in milliseconds.
2206 Timeout in milliseconds used in NFS protocol.
2207 If you encounter "ERROR: Cannot umount" in nfs command,
2208 try longer timeout such as
2209 #define CONFIG_NFS_TIMEOUT 10000UL
2211 - Command Interpreter:
2212 CONFIG_AUTO_COMPLETE
2214 Enable auto completion of commands using TAB.
2216 Note that this feature has NOT been implemented yet
2217 for the "hush" shell.
2220 CONFIG_SYS_HUSH_PARSER
2222 Define this variable to enable the "hush" shell (from
2223 Busybox) as command line interpreter, thus enabling
2224 powerful command line syntax like
2225 if...then...else...fi conditionals or `&&' and '||'
2226 constructs ("shell scripts").
2228 If undefined, you get the old, much simpler behaviour
2229 with a somewhat smaller memory footprint.
2232 CONFIG_SYS_PROMPT_HUSH_PS2
2234 This defines the secondary prompt string, which is
2235 printed when the command interpreter needs more input
2236 to complete a command. Usually "> ".
2240 In the current implementation, the local variables
2241 space and global environment variables space are
2242 separated. Local variables are those you define by
2243 simply typing `name=value'. To access a local
2244 variable later on, you have write `$name' or
2245 `${name}'; to execute the contents of a variable
2246 directly type `$name' at the command prompt.
2248 Global environment variables are those you use
2249 setenv/printenv to work with. To run a command stored
2250 in such a variable, you need to use the run command,
2251 and you must not use the '$' sign to access them.
2253 To store commands and special characters in a
2254 variable, please use double quotation marks
2255 surrounding the whole text of the variable, instead
2256 of the backslashes before semicolons and special
2259 - Commandline Editing and History:
2260 CONFIG_CMDLINE_EDITING
2262 Enable editing and History functions for interactive
2263 commandline input operations
2265 - Default Environment:
2266 CONFIG_EXTRA_ENV_SETTINGS
2268 Define this to contain any number of null terminated
2269 strings (variable = value pairs) that will be part of
2270 the default environment compiled into the boot image.
2272 For example, place something like this in your
2273 board's config file:
2275 #define CONFIG_EXTRA_ENV_SETTINGS \
2279 Warning: This method is based on knowledge about the
2280 internal format how the environment is stored by the
2281 U-Boot code. This is NOT an official, exported
2282 interface! Although it is unlikely that this format
2283 will change soon, there is no guarantee either.
2284 You better know what you are doing here.
2286 Note: overly (ab)use of the default environment is
2287 discouraged. Make sure to check other ways to preset
2288 the environment like the "source" command or the
2291 CONFIG_ENV_VARS_UBOOT_CONFIG
2293 Define this in order to add variables describing the
2294 U-Boot build configuration to the default environment.
2295 These will be named arch, cpu, board, vendor, and soc.
2297 Enabling this option will cause the following to be defined:
2305 - DataFlash Support:
2306 CONFIG_HAS_DATAFLASH
2308 Defining this option enables DataFlash features and
2309 allows to read/write in Dataflash via the standard
2312 - Serial Flash support
2315 Defining this option enables SPI flash commands
2316 'sf probe/read/write/erase/update'.
2318 Usage requires an initial 'probe' to define the serial
2319 flash parameters, followed by read/write/erase/update
2322 The following defaults may be provided by the platform
2323 to handle the common case when only a single serial
2324 flash is present on the system.
2326 CONFIG_SF_DEFAULT_BUS Bus identifier
2327 CONFIG_SF_DEFAULT_CS Chip-select
2328 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2329 CONFIG_SF_DEFAULT_SPEED in Hz
2331 - SystemACE Support:
2334 Adding this option adds support for Xilinx SystemACE
2335 chips attached via some sort of local bus. The address
2336 of the chip must also be defined in the
2337 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2339 #define CONFIG_SYSTEMACE
2340 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2342 When SystemACE support is added, the "ace" device type
2343 becomes available to the fat commands, i.e. fatls.
2345 - TFTP Fixed UDP Port:
2348 If this is defined, the environment variable tftpsrcp
2349 is used to supply the TFTP UDP source port value.
2350 If tftpsrcp isn't defined, the normal pseudo-random port
2351 number generator is used.
2353 Also, the environment variable tftpdstp is used to supply
2354 the TFTP UDP destination port value. If tftpdstp isn't
2355 defined, the normal port 69 is used.
2357 The purpose for tftpsrcp is to allow a TFTP server to
2358 blindly start the TFTP transfer using the pre-configured
2359 target IP address and UDP port. This has the effect of
2360 "punching through" the (Windows XP) firewall, allowing
2361 the remainder of the TFTP transfer to proceed normally.
2362 A better solution is to properly configure the firewall,
2363 but sometimes that is not allowed.
2365 - Show boot progress:
2366 CONFIG_SHOW_BOOT_PROGRESS
2368 Defining this option allows to add some board-
2369 specific code (calling a user-provided function
2370 "show_boot_progress(int)") that enables you to show
2371 the system's boot progress on some display (for
2372 example, some LED's) on your board. At the moment,
2373 the following checkpoints are implemented:
2375 - Detailed boot stage timing
2377 Define this option to get detailed timing of each stage
2378 of the boot process.
2380 CONFIG_BOOTSTAGE_USER_COUNT
2381 This is the number of available user bootstage records.
2382 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2383 a new ID will be allocated from this stash. If you exceed
2384 the limit, recording will stop.
2386 CONFIG_BOOTSTAGE_REPORT
2387 Define this to print a report before boot, similar to this:
2389 Timer summary in microseconds:
2392 3,575,678 3,575,678 board_init_f start
2393 3,575,695 17 arch_cpu_init A9
2394 3,575,777 82 arch_cpu_init done
2395 3,659,598 83,821 board_init_r start
2396 3,910,375 250,777 main_loop
2397 29,916,167 26,005,792 bootm_start
2398 30,361,327 445,160 start_kernel
2400 CONFIG_CMD_BOOTSTAGE
2401 Add a 'bootstage' command which supports printing a report
2402 and un/stashing of bootstage data.
2404 CONFIG_BOOTSTAGE_FDT
2405 Stash the bootstage information in the FDT. A root 'bootstage'
2406 node is created with each bootstage id as a child. Each child
2407 has a 'name' property and either 'mark' containing the
2408 mark time in microsecond, or 'accum' containing the
2409 accumulated time for that bootstage id in microseconds.
2414 name = "board_init_f";
2423 Code in the Linux kernel can find this in /proc/devicetree.
2425 Legacy uImage format:
2428 1 common/cmd_bootm.c before attempting to boot an image
2429 -1 common/cmd_bootm.c Image header has bad magic number
2430 2 common/cmd_bootm.c Image header has correct magic number
2431 -2 common/cmd_bootm.c Image header has bad checksum
2432 3 common/cmd_bootm.c Image header has correct checksum
2433 -3 common/cmd_bootm.c Image data has bad checksum
2434 4 common/cmd_bootm.c Image data has correct checksum
2435 -4 common/cmd_bootm.c Image is for unsupported architecture
2436 5 common/cmd_bootm.c Architecture check OK
2437 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2438 6 common/cmd_bootm.c Image Type check OK
2439 -6 common/cmd_bootm.c gunzip uncompression error
2440 -7 common/cmd_bootm.c Unimplemented compression type
2441 7 common/cmd_bootm.c Uncompression OK
2442 8 common/cmd_bootm.c No uncompress/copy overwrite error
2443 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2445 9 common/image.c Start initial ramdisk verification
2446 -10 common/image.c Ramdisk header has bad magic number
2447 -11 common/image.c Ramdisk header has bad checksum
2448 10 common/image.c Ramdisk header is OK
2449 -12 common/image.c Ramdisk data has bad checksum
2450 11 common/image.c Ramdisk data has correct checksum
2451 12 common/image.c Ramdisk verification complete, start loading
2452 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2453 13 common/image.c Start multifile image verification
2454 14 common/image.c No initial ramdisk, no multifile, continue.
2456 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2458 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2459 -31 post/post.c POST test failed, detected by post_output_backlog()
2460 -32 post/post.c POST test failed, detected by post_run_single()
2462 34 common/cmd_doc.c before loading a Image from a DOC device
2463 -35 common/cmd_doc.c Bad usage of "doc" command
2464 35 common/cmd_doc.c correct usage of "doc" command
2465 -36 common/cmd_doc.c No boot device
2466 36 common/cmd_doc.c correct boot device
2467 -37 common/cmd_doc.c Unknown Chip ID on boot device
2468 37 common/cmd_doc.c correct chip ID found, device available
2469 -38 common/cmd_doc.c Read Error on boot device
2470 38 common/cmd_doc.c reading Image header from DOC device OK
2471 -39 common/cmd_doc.c Image header has bad magic number
2472 39 common/cmd_doc.c Image header has correct magic number
2473 -40 common/cmd_doc.c Error reading Image from DOC device
2474 40 common/cmd_doc.c Image header has correct magic number
2475 41 common/cmd_ide.c before loading a Image from a IDE device
2476 -42 common/cmd_ide.c Bad usage of "ide" command
2477 42 common/cmd_ide.c correct usage of "ide" command
2478 -43 common/cmd_ide.c No boot device
2479 43 common/cmd_ide.c boot device found
2480 -44 common/cmd_ide.c Device not available
2481 44 common/cmd_ide.c Device available
2482 -45 common/cmd_ide.c wrong partition selected
2483 45 common/cmd_ide.c partition selected
2484 -46 common/cmd_ide.c Unknown partition table
2485 46 common/cmd_ide.c valid partition table found
2486 -47 common/cmd_ide.c Invalid partition type
2487 47 common/cmd_ide.c correct partition type
2488 -48 common/cmd_ide.c Error reading Image Header on boot device
2489 48 common/cmd_ide.c reading Image Header from IDE device OK
2490 -49 common/cmd_ide.c Image header has bad magic number
2491 49 common/cmd_ide.c Image header has correct magic number
2492 -50 common/cmd_ide.c Image header has bad checksum
2493 50 common/cmd_ide.c Image header has correct checksum
2494 -51 common/cmd_ide.c Error reading Image from IDE device
2495 51 common/cmd_ide.c reading Image from IDE device OK
2496 52 common/cmd_nand.c before loading a Image from a NAND device
2497 -53 common/cmd_nand.c Bad usage of "nand" command
2498 53 common/cmd_nand.c correct usage of "nand" command
2499 -54 common/cmd_nand.c No boot device
2500 54 common/cmd_nand.c boot device found
2501 -55 common/cmd_nand.c Unknown Chip ID on boot device
2502 55 common/cmd_nand.c correct chip ID found, device available
2503 -56 common/cmd_nand.c Error reading Image Header on boot device
2504 56 common/cmd_nand.c reading Image Header from NAND device OK
2505 -57 common/cmd_nand.c Image header has bad magic number
2506 57 common/cmd_nand.c Image header has correct magic number
2507 -58 common/cmd_nand.c Error reading Image from NAND device
2508 58 common/cmd_nand.c reading Image from NAND device OK
2510 -60 common/env_common.c Environment has a bad CRC, using default
2512 64 net/eth.c starting with Ethernet configuration.
2513 -64 net/eth.c no Ethernet found.
2514 65 net/eth.c Ethernet found.
2516 -80 common/cmd_net.c usage wrong
2517 80 common/cmd_net.c before calling NetLoop()
2518 -81 common/cmd_net.c some error in NetLoop() occurred
2519 81 common/cmd_net.c NetLoop() back without error
2520 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2521 82 common/cmd_net.c trying automatic boot
2522 83 common/cmd_net.c running "source" command
2523 -83 common/cmd_net.c some error in automatic boot or "source" command
2524 84 common/cmd_net.c end without errors
2529 100 common/cmd_bootm.c Kernel FIT Image has correct format
2530 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2531 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2532 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2533 102 common/cmd_bootm.c Kernel unit name specified
2534 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2535 103 common/cmd_bootm.c Found configuration node
2536 104 common/cmd_bootm.c Got kernel subimage node offset
2537 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2538 105 common/cmd_bootm.c Kernel subimage hash verification OK
2539 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2540 106 common/cmd_bootm.c Architecture check OK
2541 -106 common/cmd_bootm.c Kernel subimage has wrong type
2542 107 common/cmd_bootm.c Kernel subimage type OK
2543 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2544 108 common/cmd_bootm.c Got kernel subimage data/size
2545 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2546 -109 common/cmd_bootm.c Can't get kernel subimage type
2547 -110 common/cmd_bootm.c Can't get kernel subimage comp
2548 -111 common/cmd_bootm.c Can't get kernel subimage os
2549 -112 common/cmd_bootm.c Can't get kernel subimage load address
2550 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2552 120 common/image.c Start initial ramdisk verification
2553 -120 common/image.c Ramdisk FIT image has incorrect format
2554 121 common/image.c Ramdisk FIT image has correct format
2555 122 common/image.c No ramdisk subimage unit name, using configuration
2556 -122 common/image.c Can't get configuration for ramdisk subimage
2557 123 common/image.c Ramdisk unit name specified
2558 -124 common/image.c Can't get ramdisk subimage node offset
2559 125 common/image.c Got ramdisk subimage node offset
2560 -125 common/image.c Ramdisk subimage hash verification failed
2561 126 common/image.c Ramdisk subimage hash verification OK
2562 -126 common/image.c Ramdisk subimage for unsupported architecture
2563 127 common/image.c Architecture check OK
2564 -127 common/image.c Can't get ramdisk subimage data/size
2565 128 common/image.c Got ramdisk subimage data/size
2566 129 common/image.c Can't get ramdisk load address
2567 -129 common/image.c Got ramdisk load address
2569 -130 common/cmd_doc.c Incorrect FIT image format
2570 131 common/cmd_doc.c FIT image format OK
2572 -140 common/cmd_ide.c Incorrect FIT image format
2573 141 common/cmd_ide.c FIT image format OK
2575 -150 common/cmd_nand.c Incorrect FIT image format
2576 151 common/cmd_nand.c FIT image format OK
2578 - Standalone program support:
2579 CONFIG_STANDALONE_LOAD_ADDR
2581 This option defines a board specific value for the
2582 address where standalone program gets loaded, thus
2583 overwriting the architecture dependent default
2586 - Frame Buffer Address:
2589 Define CONFIG_FB_ADDR if you want to use specific
2590 address for frame buffer.
2591 Then system will reserve the frame buffer address to
2592 defined address instead of lcd_setmem (this function
2593 grabs the memory for frame buffer by panel's size).
2595 Please see board_init_f function.
2597 - Automatic software updates via TFTP server
2599 CONFIG_UPDATE_TFTP_CNT_MAX
2600 CONFIG_UPDATE_TFTP_MSEC_MAX
2602 These options enable and control the auto-update feature;
2603 for a more detailed description refer to doc/README.update.
2605 - MTD Support (mtdparts command, UBI support)
2608 Adds the MTD device infrastructure from the Linux kernel.
2609 Needed for mtdparts command support.
2611 CONFIG_MTD_PARTITIONS
2613 Adds the MTD partitioning infrastructure from the Linux
2614 kernel. Needed for UBI support.
2618 Enable building of SPL globally.
2621 LDSCRIPT for linking the SPL binary.
2624 Maximum binary size (text, data and rodata) of the SPL binary.
2626 CONFIG_SPL_TEXT_BASE
2627 TEXT_BASE for linking the SPL binary.
2629 CONFIG_SPL_BSS_START_ADDR
2630 Link address for the BSS within the SPL binary.
2632 CONFIG_SPL_BSS_MAX_SIZE
2633 Maximum binary size of the BSS section of the SPL binary.
2636 Adress of the start of the stack SPL will use
2638 CONFIG_SYS_SPL_MALLOC_START
2639 Starting address of the malloc pool used in SPL.
2641 CONFIG_SYS_SPL_MALLOC_SIZE
2642 The size of the malloc pool used in SPL.
2644 CONFIG_SPL_FRAMEWORK
2645 Enable the SPL framework under common/. This framework
2646 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2647 NAND loading of the Linux Kernel.
2649 CONFIG_SPL_DISPLAY_PRINT
2650 For ARM, enable an optional function to print more information
2651 about the running system.
2653 CONFIG_SPL_LIBCOMMON_SUPPORT
2654 Support for common/libcommon.o in SPL binary
2656 CONFIG_SPL_LIBDISK_SUPPORT
2657 Support for disk/libdisk.o in SPL binary
2659 CONFIG_SPL_I2C_SUPPORT
2660 Support for drivers/i2c/libi2c.o in SPL binary
2662 CONFIG_SPL_GPIO_SUPPORT
2663 Support for drivers/gpio/libgpio.o in SPL binary
2665 CONFIG_SPL_MMC_SUPPORT
2666 Support for drivers/mmc/libmmc.o in SPL binary
2668 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2669 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2670 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2671 Address, size and partition on the MMC to load U-Boot from
2672 when the MMC is being used in raw mode.
2674 CONFIG_SPL_FAT_SUPPORT
2675 Support for fs/fat/libfat.o in SPL binary
2677 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2678 Filename to read to load U-Boot when reading from FAT
2680 CONFIG_SPL_NAND_SIMPLE
2681 Support for drivers/mtd/nand/libnand.o in SPL binary
2683 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2684 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2685 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2686 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2687 CONFIG_SYS_NAND_ECCBYTES
2688 Defines the size and behavior of the NAND that SPL uses
2689 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2691 CONFIG_SYS_NAND_U_BOOT_OFFS
2692 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2695 CONFIG_SYS_NAND_U_BOOT_START
2696 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2699 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2700 Define this if you need to first read the OOB and then the
2701 data. This is used for example on davinci plattforms.
2703 CONFIG_SPL_OMAP3_ID_NAND
2704 Support for an OMAP3-specific set of functions to return the
2705 ID and MFR of the first attached NAND chip, if present.
2707 CONFIG_SPL_SERIAL_SUPPORT
2708 Support for drivers/serial/libserial.o in SPL binary
2710 CONFIG_SPL_SPI_FLASH_SUPPORT
2711 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2713 CONFIG_SPL_SPI_SUPPORT
2714 Support for drivers/spi/libspi.o in SPL binary
2716 CONFIG_SPL_RAM_DEVICE
2717 Support for running image already present in ram, in SPL binary
2719 CONFIG_SPL_LIBGENERIC_SUPPORT
2720 Support for lib/libgeneric.o in SPL binary
2725 [so far only for SMDK2400 boards]
2727 - Modem support enable:
2728 CONFIG_MODEM_SUPPORT
2730 - RTS/CTS Flow control enable:
2733 - Modem debug support:
2734 CONFIG_MODEM_SUPPORT_DEBUG
2736 Enables debugging stuff (char screen[1024], dbg())
2737 for modem support. Useful only with BDI2000.
2739 - Interrupt support (PPC):
2741 There are common interrupt_init() and timer_interrupt()
2742 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2743 for CPU specific initialization. interrupt_init_cpu()
2744 should set decrementer_count to appropriate value. If
2745 CPU resets decrementer automatically after interrupt
2746 (ppc4xx) it should set decrementer_count to zero.
2747 timer_interrupt() calls timer_interrupt_cpu() for CPU
2748 specific handling. If board has watchdog / status_led
2749 / other_activity_monitor it works automatically from
2750 general timer_interrupt().
2754 In the target system modem support is enabled when a
2755 specific key (key combination) is pressed during
2756 power-on. Otherwise U-Boot will boot normally
2757 (autoboot). The key_pressed() function is called from
2758 board_init(). Currently key_pressed() is a dummy
2759 function, returning 1 and thus enabling modem
2762 If there are no modem init strings in the
2763 environment, U-Boot proceed to autoboot; the
2764 previous output (banner, info printfs) will be
2767 See also: doc/README.Modem
2769 Board initialization settings:
2770 ------------------------------
2772 During Initialization u-boot calls a number of board specific functions
2773 to allow the preparation of board specific prerequisites, e.g. pin setup
2774 before drivers are initialized. To enable these callbacks the
2775 following configuration macros have to be defined. Currently this is
2776 architecture specific, so please check arch/your_architecture/lib/board.c
2777 typically in board_init_f() and board_init_r().
2779 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2780 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2781 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2782 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2784 Configuration Settings:
2785 -----------------------
2787 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2788 undefine this when you're short of memory.
2790 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2791 width of the commands listed in the 'help' command output.
2793 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2794 prompt for user input.
2796 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2798 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2800 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2802 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2803 the application (usually a Linux kernel) when it is
2806 - CONFIG_SYS_BAUDRATE_TABLE:
2807 List of legal baudrate settings for this board.
2809 - CONFIG_SYS_CONSOLE_INFO_QUIET
2810 Suppress display of console information at boot.
2812 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2813 If the board specific function
2814 extern int overwrite_console (void);
2815 returns 1, the stdin, stderr and stdout are switched to the
2816 serial port, else the settings in the environment are used.
2818 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2819 Enable the call to overwrite_console().
2821 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2822 Enable overwrite of previous console environment settings.
2824 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2825 Begin and End addresses of the area used by the
2828 - CONFIG_SYS_ALT_MEMTEST:
2829 Enable an alternate, more extensive memory test.
2831 - CONFIG_SYS_MEMTEST_SCRATCH:
2832 Scratch address used by the alternate memory test
2833 You only need to set this if address zero isn't writeable
2835 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2836 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2837 this specified memory area will get subtracted from the top
2838 (end) of RAM and won't get "touched" at all by U-Boot. By
2839 fixing up gd->ram_size the Linux kernel should gets passed
2840 the now "corrected" memory size and won't touch it either.
2841 This should work for arch/ppc and arch/powerpc. Only Linux
2842 board ports in arch/powerpc with bootwrapper support that
2843 recalculate the memory size from the SDRAM controller setup
2844 will have to get fixed in Linux additionally.
2846 This option can be used as a workaround for the 440EPx/GRx
2847 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2850 WARNING: Please make sure that this value is a multiple of
2851 the Linux page size (normally 4k). If this is not the case,
2852 then the end address of the Linux memory will be located at a
2853 non page size aligned address and this could cause major
2856 - CONFIG_SYS_TFTP_LOADADDR:
2857 Default load address for network file downloads
2859 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2860 Enable temporary baudrate change while serial download
2862 - CONFIG_SYS_SDRAM_BASE:
2863 Physical start address of SDRAM. _Must_ be 0 here.
2865 - CONFIG_SYS_MBIO_BASE:
2866 Physical start address of Motherboard I/O (if using a
2869 - CONFIG_SYS_FLASH_BASE:
2870 Physical start address of Flash memory.
2872 - CONFIG_SYS_MONITOR_BASE:
2873 Physical start address of boot monitor code (set by
2874 make config files to be same as the text base address
2875 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2876 CONFIG_SYS_FLASH_BASE when booting from flash.
2878 - CONFIG_SYS_MONITOR_LEN:
2879 Size of memory reserved for monitor code, used to
2880 determine _at_compile_time_ (!) if the environment is
2881 embedded within the U-Boot image, or in a separate
2884 - CONFIG_SYS_MALLOC_LEN:
2885 Size of DRAM reserved for malloc() use.
2887 - CONFIG_SYS_BOOTM_LEN:
2888 Normally compressed uImages are limited to an
2889 uncompressed size of 8 MBytes. If this is not enough,
2890 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2891 to adjust this setting to your needs.
2893 - CONFIG_SYS_BOOTMAPSZ:
2894 Maximum size of memory mapped by the startup code of
2895 the Linux kernel; all data that must be processed by
2896 the Linux kernel (bd_info, boot arguments, FDT blob if
2897 used) must be put below this limit, unless "bootm_low"
2898 enviroment variable is defined and non-zero. In such case
2899 all data for the Linux kernel must be between "bootm_low"
2900 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2901 variable "bootm_mapsize" will override the value of
2902 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2903 then the value in "bootm_size" will be used instead.
2905 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2906 Enable initrd_high functionality. If defined then the
2907 initrd_high feature is enabled and the bootm ramdisk subcommand
2910 - CONFIG_SYS_BOOT_GET_CMDLINE:
2911 Enables allocating and saving kernel cmdline in space between
2912 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2914 - CONFIG_SYS_BOOT_GET_KBD:
2915 Enables allocating and saving a kernel copy of the bd_info in
2916 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2918 - CONFIG_SYS_MAX_FLASH_BANKS:
2919 Max number of Flash memory banks
2921 - CONFIG_SYS_MAX_FLASH_SECT:
2922 Max number of sectors on a Flash chip
2924 - CONFIG_SYS_FLASH_ERASE_TOUT:
2925 Timeout for Flash erase operations (in ms)
2927 - CONFIG_SYS_FLASH_WRITE_TOUT:
2928 Timeout for Flash write operations (in ms)
2930 - CONFIG_SYS_FLASH_LOCK_TOUT
2931 Timeout for Flash set sector lock bit operation (in ms)
2933 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2934 Timeout for Flash clear lock bits operation (in ms)
2936 - CONFIG_SYS_FLASH_PROTECTION
2937 If defined, hardware flash sectors protection is used
2938 instead of U-Boot software protection.
2940 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2942 Enable TFTP transfers directly to flash memory;
2943 without this option such a download has to be
2944 performed in two steps: (1) download to RAM, and (2)
2945 copy from RAM to flash.
2947 The two-step approach is usually more reliable, since
2948 you can check if the download worked before you erase
2949 the flash, but in some situations (when system RAM is
2950 too limited to allow for a temporary copy of the
2951 downloaded image) this option may be very useful.
2953 - CONFIG_SYS_FLASH_CFI:
2954 Define if the flash driver uses extra elements in the
2955 common flash structure for storing flash geometry.
2957 - CONFIG_FLASH_CFI_DRIVER
2958 This option also enables the building of the cfi_flash driver
2959 in the drivers directory
2961 - CONFIG_FLASH_CFI_MTD
2962 This option enables the building of the cfi_mtd driver
2963 in the drivers directory. The driver exports CFI flash
2966 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2967 Use buffered writes to flash.
2969 - CONFIG_FLASH_SPANSION_S29WS_N
2970 s29ws-n MirrorBit flash has non-standard addresses for buffered
2973 - CONFIG_SYS_FLASH_QUIET_TEST
2974 If this option is defined, the common CFI flash doesn't
2975 print it's warning upon not recognized FLASH banks. This
2976 is useful, if some of the configured banks are only
2977 optionally available.
2979 - CONFIG_FLASH_SHOW_PROGRESS
2980 If defined (must be an integer), print out countdown
2981 digits and dots. Recommended value: 45 (9..1) for 80
2982 column displays, 15 (3..1) for 40 column displays.
2984 - CONFIG_SYS_RX_ETH_BUFFER:
2985 Defines the number of Ethernet receive buffers. On some
2986 Ethernet controllers it is recommended to set this value
2987 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2988 buffers can be full shortly after enabling the interface
2989 on high Ethernet traffic.
2990 Defaults to 4 if not defined.
2992 - CONFIG_ENV_MAX_ENTRIES
2994 Maximum number of entries in the hash table that is used
2995 internally to store the environment settings. The default
2996 setting is supposed to be generous and should work in most
2997 cases. This setting can be used to tune behaviour; see
2998 lib/hashtable.c for details.
3000 The following definitions that deal with the placement and management
3001 of environment data (variable area); in general, we support the
3002 following configurations:
3004 - CONFIG_BUILD_ENVCRC:
3006 Builds up envcrc with the target environment so that external utils
3007 may easily extract it and embed it in final U-Boot images.
3009 - CONFIG_ENV_IS_IN_FLASH:
3011 Define this if the environment is in flash memory.
3013 a) The environment occupies one whole flash sector, which is
3014 "embedded" in the text segment with the U-Boot code. This
3015 happens usually with "bottom boot sector" or "top boot
3016 sector" type flash chips, which have several smaller
3017 sectors at the start or the end. For instance, such a
3018 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3019 such a case you would place the environment in one of the
3020 4 kB sectors - with U-Boot code before and after it. With
3021 "top boot sector" type flash chips, you would put the
3022 environment in one of the last sectors, leaving a gap
3023 between U-Boot and the environment.
3025 - CONFIG_ENV_OFFSET:
3027 Offset of environment data (variable area) to the
3028 beginning of flash memory; for instance, with bottom boot
3029 type flash chips the second sector can be used: the offset
3030 for this sector is given here.
3032 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3036 This is just another way to specify the start address of
3037 the flash sector containing the environment (instead of
3040 - CONFIG_ENV_SECT_SIZE:
3042 Size of the sector containing the environment.
3045 b) Sometimes flash chips have few, equal sized, BIG sectors.
3046 In such a case you don't want to spend a whole sector for
3051 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3052 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3053 of this flash sector for the environment. This saves
3054 memory for the RAM copy of the environment.
3056 It may also save flash memory if you decide to use this
3057 when your environment is "embedded" within U-Boot code,
3058 since then the remainder of the flash sector could be used
3059 for U-Boot code. It should be pointed out that this is
3060 STRONGLY DISCOURAGED from a robustness point of view:
3061 updating the environment in flash makes it always
3062 necessary to erase the WHOLE sector. If something goes
3063 wrong before the contents has been restored from a copy in
3064 RAM, your target system will be dead.
3066 - CONFIG_ENV_ADDR_REDUND
3067 CONFIG_ENV_SIZE_REDUND
3069 These settings describe a second storage area used to hold
3070 a redundant copy of the environment data, so that there is
3071 a valid backup copy in case there is a power failure during
3072 a "saveenv" operation.
3074 BE CAREFUL! Any changes to the flash layout, and some changes to the
3075 source code will make it necessary to adapt <board>/u-boot.lds*
3079 - CONFIG_ENV_IS_IN_NVRAM:
3081 Define this if you have some non-volatile memory device
3082 (NVRAM, battery buffered SRAM) which you want to use for the
3088 These two #defines are used to determine the memory area you
3089 want to use for environment. It is assumed that this memory
3090 can just be read and written to, without any special
3093 BE CAREFUL! The first access to the environment happens quite early
3094 in U-Boot initalization (when we try to get the setting of for the
3095 console baudrate). You *MUST* have mapped your NVRAM area then, or
3098 Please note that even with NVRAM we still use a copy of the
3099 environment in RAM: we could work on NVRAM directly, but we want to
3100 keep settings there always unmodified except somebody uses "saveenv"
3101 to save the current settings.
3104 - CONFIG_ENV_IS_IN_EEPROM:
3106 Use this if you have an EEPROM or similar serial access
3107 device and a driver for it.
3109 - CONFIG_ENV_OFFSET:
3112 These two #defines specify the offset and size of the
3113 environment area within the total memory of your EEPROM.
3115 - CONFIG_SYS_I2C_EEPROM_ADDR:
3116 If defined, specified the chip address of the EEPROM device.
3117 The default address is zero.
3119 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3120 If defined, the number of bits used to address bytes in a
3121 single page in the EEPROM device. A 64 byte page, for example
3122 would require six bits.
3124 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3125 If defined, the number of milliseconds to delay between
3126 page writes. The default is zero milliseconds.
3128 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3129 The length in bytes of the EEPROM memory array address. Note
3130 that this is NOT the chip address length!
3132 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3133 EEPROM chips that implement "address overflow" are ones
3134 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3135 address and the extra bits end up in the "chip address" bit
3136 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3139 Note that we consider the length of the address field to
3140 still be one byte because the extra address bits are hidden
3141 in the chip address.
3143 - CONFIG_SYS_EEPROM_SIZE:
3144 The size in bytes of the EEPROM device.
3146 - CONFIG_ENV_EEPROM_IS_ON_I2C
3147 define this, if you have I2C and SPI activated, and your
3148 EEPROM, which holds the environment, is on the I2C bus.
3150 - CONFIG_I2C_ENV_EEPROM_BUS
3151 if you have an Environment on an EEPROM reached over
3152 I2C muxes, you can define here, how to reach this
3153 EEPROM. For example:
3155 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3157 EEPROM which holds the environment, is reached over
3158 a pca9547 i2c mux with address 0x70, channel 3.
3160 - CONFIG_ENV_IS_IN_DATAFLASH:
3162 Define this if you have a DataFlash memory device which you
3163 want to use for the environment.
3165 - CONFIG_ENV_OFFSET:
3169 These three #defines specify the offset and size of the
3170 environment area within the total memory of your DataFlash placed
3171 at the specified address.
3173 - CONFIG_ENV_IS_IN_REMOTE:
3175 Define this if you have a remote memory space which you
3176 want to use for the local device's environment.
3181 These two #defines specify the address and size of the
3182 environment area within the remote memory space. The
3183 local device can get the environment from remote memory
3184 space by SRIO or PCIE links.
3186 BE CAREFUL! For some special cases, the local device can not use
3187 "saveenv" command. For example, the local device will get the
3188 environment stored in a remote NOR flash by SRIO or PCIE link,
3189 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3191 - CONFIG_ENV_IS_IN_NAND:
3193 Define this if you have a NAND device which you want to use
3194 for the environment.
3196 - CONFIG_ENV_OFFSET:
3199 These two #defines specify the offset and size of the environment
3200 area within the first NAND device. CONFIG_ENV_OFFSET must be
3201 aligned to an erase block boundary.
3203 - CONFIG_ENV_OFFSET_REDUND (optional):
3205 This setting describes a second storage area of CONFIG_ENV_SIZE
3206 size used to hold a redundant copy of the environment data, so
3207 that there is a valid backup copy in case there is a power failure
3208 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3209 aligned to an erase block boundary.
3211 - CONFIG_ENV_RANGE (optional):
3213 Specifies the length of the region in which the environment
3214 can be written. This should be a multiple of the NAND device's
3215 block size. Specifying a range with more erase blocks than
3216 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3217 the range to be avoided.
3219 - CONFIG_ENV_OFFSET_OOB (optional):
3221 Enables support for dynamically retrieving the offset of the
3222 environment from block zero's out-of-band data. The
3223 "nand env.oob" command can be used to record this offset.
3224 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3225 using CONFIG_ENV_OFFSET_OOB.
3227 - CONFIG_NAND_ENV_DST
3229 Defines address in RAM to which the nand_spl code should copy the
3230 environment. If redundant environment is used, it will be copied to
3231 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3233 - CONFIG_SYS_SPI_INIT_OFFSET
3235 Defines offset to the initial SPI buffer area in DPRAM. The
3236 area is used at an early stage (ROM part) if the environment
3237 is configured to reside in the SPI EEPROM: We need a 520 byte
3238 scratch DPRAM area. It is used between the two initialization
3239 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3240 to be a good choice since it makes it far enough from the
3241 start of the data area as well as from the stack pointer.
3243 Please note that the environment is read-only until the monitor
3244 has been relocated to RAM and a RAM copy of the environment has been
3245 created; also, when using EEPROM you will have to use getenv_f()
3246 until then to read environment variables.
3248 The environment is protected by a CRC32 checksum. Before the monitor
3249 is relocated into RAM, as a result of a bad CRC you will be working
3250 with the compiled-in default environment - *silently*!!! [This is
3251 necessary, because the first environment variable we need is the
3252 "baudrate" setting for the console - if we have a bad CRC, we don't
3253 have any device yet where we could complain.]
3255 Note: once the monitor has been relocated, then it will complain if
3256 the default environment is used; a new CRC is computed as soon as you
3257 use the "saveenv" command to store a valid environment.
3259 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3260 Echo the inverted Ethernet link state to the fault LED.
3262 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3263 also needs to be defined.
3265 - CONFIG_SYS_FAULT_MII_ADDR:
3266 MII address of the PHY to check for the Ethernet link state.
3268 - CONFIG_NS16550_MIN_FUNCTIONS:
3269 Define this if you desire to only have use of the NS16550_init
3270 and NS16550_putc functions for the serial driver located at
3271 drivers/serial/ns16550.c. This option is useful for saving
3272 space for already greatly restricted images, including but not
3273 limited to NAND_SPL configurations.
3275 Low Level (hardware related) configuration options:
3276 ---------------------------------------------------
3278 - CONFIG_SYS_CACHELINE_SIZE:
3279 Cache Line Size of the CPU.
3281 - CONFIG_SYS_DEFAULT_IMMR:
3282 Default address of the IMMR after system reset.
3284 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3285 and RPXsuper) to be able to adjust the position of
3286 the IMMR register after a reset.
3288 - CONFIG_SYS_CCSRBAR_DEFAULT:
3289 Default (power-on reset) physical address of CCSR on Freescale
3292 - CONFIG_SYS_CCSRBAR:
3293 Virtual address of CCSR. On a 32-bit build, this is typically
3294 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3296 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3297 for cross-platform code that uses that macro instead.
3299 - CONFIG_SYS_CCSRBAR_PHYS:
3300 Physical address of CCSR. CCSR can be relocated to a new
3301 physical address, if desired. In this case, this macro should
3302 be set to that address. Otherwise, it should be set to the
3303 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3304 is typically relocated on 36-bit builds. It is recommended
3305 that this macro be defined via the _HIGH and _LOW macros:
3307 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3308 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3310 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3311 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3312 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3313 used in assembly code, so it must not contain typecasts or
3314 integer size suffixes (e.g. "ULL").
3316 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3317 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3318 used in assembly code, so it must not contain typecasts or
3319 integer size suffixes (e.g. "ULL").
3321 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3322 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3323 forced to a value that ensures that CCSR is not relocated.
3325 - Floppy Disk Support:
3326 CONFIG_SYS_FDC_DRIVE_NUMBER
3328 the default drive number (default value 0)
3330 CONFIG_SYS_ISA_IO_STRIDE
3332 defines the spacing between FDC chipset registers
3335 CONFIG_SYS_ISA_IO_OFFSET
3337 defines the offset of register from address. It
3338 depends on which part of the data bus is connected to
3339 the FDC chipset. (default value 0)
3341 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3342 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3345 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3346 fdc_hw_init() is called at the beginning of the FDC
3347 setup. fdc_hw_init() must be provided by the board
3348 source code. It is used to make hardware dependant
3352 Most IDE controllers were designed to be connected with PCI
3353 interface. Only few of them were designed for AHB interface.
3354 When software is doing ATA command and data transfer to
3355 IDE devices through IDE-AHB controller, some additional
3356 registers accessing to these kind of IDE-AHB controller
3359 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3360 DO NOT CHANGE unless you know exactly what you're
3361 doing! (11-4) [MPC8xx/82xx systems only]
3363 - CONFIG_SYS_INIT_RAM_ADDR:
3365 Start address of memory area that can be used for
3366 initial data and stack; please note that this must be
3367 writable memory that is working WITHOUT special
3368 initialization, i. e. you CANNOT use normal RAM which
3369 will become available only after programming the
3370 memory controller and running certain initialization
3373 U-Boot uses the following memory types:
3374 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3375 - MPC824X: data cache
3376 - PPC4xx: data cache
3378 - CONFIG_SYS_GBL_DATA_OFFSET:
3380 Offset of the initial data structure in the memory
3381 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3382 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3383 data is located at the end of the available space
3384 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3385 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3386 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3387 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3390 On the MPC824X (or other systems that use the data
3391 cache for initial memory) the address chosen for
3392 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3393 point to an otherwise UNUSED address space between
3394 the top of RAM and the start of the PCI space.
3396 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3398 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3400 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3402 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3404 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3406 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3408 - CONFIG_SYS_OR_TIMING_SDRAM:
3411 - CONFIG_SYS_MAMR_PTA:
3412 periodic timer for refresh
3414 - CONFIG_SYS_DER: Debug Event Register (37-47)
3416 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3417 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3418 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3419 CONFIG_SYS_BR1_PRELIM:
3420 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3422 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3423 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3424 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3425 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3427 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3428 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3429 Machine Mode Register and Memory Periodic Timer
3430 Prescaler definitions (SDRAM timing)
3432 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3433 enable I2C microcode relocation patch (MPC8xx);
3434 define relocation offset in DPRAM [DSP2]
3436 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3437 enable SMC microcode relocation patch (MPC8xx);
3438 define relocation offset in DPRAM [SMC1]
3440 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3441 enable SPI microcode relocation patch (MPC8xx);
3442 define relocation offset in DPRAM [SCC4]
3444 - CONFIG_SYS_USE_OSCCLK:
3445 Use OSCM clock mode on MBX8xx board. Be careful,
3446 wrong setting might damage your board. Read
3447 doc/README.MBX before setting this variable!
3449 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3450 Offset of the bootmode word in DPRAM used by post
3451 (Power On Self Tests). This definition overrides
3452 #define'd default value in commproc.h resp.
3455 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3456 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3457 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3458 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3459 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3460 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3461 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3462 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3463 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3465 - CONFIG_PCI_DISABLE_PCIE:
3466 Disable PCI-Express on systems where it is supported but not
3469 - CONFIG_PCI_ENUM_ONLY
3470 Only scan through and get the devices on the busses.
3471 Don't do any setup work, presumably because someone or
3472 something has already done it, and we don't need to do it
3473 a second time. Useful for platforms that are pre-booted
3474 by coreboot or similar.
3477 Chip has SRIO or not
3480 Board has SRIO 1 port available
3483 Board has SRIO 2 port available
3485 - CONFIG_SYS_SRIOn_MEM_VIRT:
3486 Virtual Address of SRIO port 'n' memory region
3488 - CONFIG_SYS_SRIOn_MEM_PHYS:
3489 Physical Address of SRIO port 'n' memory region
3491 - CONFIG_SYS_SRIOn_MEM_SIZE:
3492 Size of SRIO port 'n' memory region
3494 - CONFIG_SYS_NDFC_16
3495 Defined to tell the NDFC that the NAND chip is using a
3498 - CONFIG_SYS_NDFC_EBC0_CFG
3499 Sets the EBC0_CFG register for the NDFC. If not defined
3500 a default value will be used.
3503 Get DDR timing information from an I2C EEPROM. Common
3504 with pluggable memory modules such as SODIMMs
3507 I2C address of the SPD EEPROM
3509 - CONFIG_SYS_SPD_BUS_NUM
3510 If SPD EEPROM is on an I2C bus other than the first
3511 one, specify here. Note that the value must resolve
3512 to something your driver can deal with.
3514 - CONFIG_SYS_DDR_RAW_TIMING
3515 Get DDR timing information from other than SPD. Common with
3516 soldered DDR chips onboard without SPD. DDR raw timing
3517 parameters are extracted from datasheet and hard-coded into
3518 header files or board specific files.
3520 - CONFIG_FSL_DDR_INTERACTIVE
3521 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3523 - CONFIG_SYS_83XX_DDR_USES_CS0
3524 Only for 83xx systems. If specified, then DDR should
3525 be configured using CS0 and CS1 instead of CS2 and CS3.
3527 - CONFIG_ETHER_ON_FEC[12]
3528 Define to enable FEC[12] on a 8xx series processor.
3530 - CONFIG_FEC[12]_PHY
3531 Define to the hardcoded PHY address which corresponds
3532 to the given FEC; i. e.
3533 #define CONFIG_FEC1_PHY 4
3534 means that the PHY with address 4 is connected to FEC1
3536 When set to -1, means to probe for first available.
3538 - CONFIG_FEC[12]_PHY_NORXERR
3539 The PHY does not have a RXERR line (RMII only).
3540 (so program the FEC to ignore it).
3543 Enable RMII mode for all FECs.
3544 Note that this is a global option, we can't
3545 have one FEC in standard MII mode and another in RMII mode.
3547 - CONFIG_CRC32_VERIFY
3548 Add a verify option to the crc32 command.
3551 => crc32 -v <address> <count> <crc32>
3553 Where address/count indicate a memory area
3554 and crc32 is the correct crc32 which the
3558 Add the "loopw" memory command. This only takes effect if
3559 the memory commands are activated globally (CONFIG_CMD_MEM).
3562 Add the "mdc" and "mwc" memory commands. These are cyclic
3567 This command will print 4 bytes (10,11,12,13) each 500 ms.
3569 => mwc.l 100 12345678 10
3570 This command will write 12345678 to address 100 all 10 ms.
3572 This only takes effect if the memory commands are activated
3573 globally (CONFIG_CMD_MEM).
3575 - CONFIG_SKIP_LOWLEVEL_INIT
3576 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3577 low level initializations (like setting up the memory
3578 controller) are omitted and/or U-Boot does not
3579 relocate itself into RAM.
3581 Normally this variable MUST NOT be defined. The only
3582 exception is when U-Boot is loaded (to RAM) by some
3583 other boot loader or by a debugger which performs
3584 these initializations itself.
3587 Modifies the behaviour of start.S when compiling a loader
3588 that is executed before the actual U-Boot. E.g. when
3589 compiling a NAND SPL.
3591 - CONFIG_USE_ARCH_MEMCPY
3592 CONFIG_USE_ARCH_MEMSET
3593 If these options are used a optimized version of memcpy/memset will
3594 be used if available. These functions may be faster under some
3595 conditions but may increase the binary size.
3597 Freescale QE/FMAN Firmware Support:
3598 -----------------------------------
3600 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3601 loading of "firmware", which is encoded in the QE firmware binary format.
3602 This firmware often needs to be loaded during U-Boot booting, so macros
3603 are used to identify the storage device (NOR flash, SPI, etc) and the address
3606 - CONFIG_SYS_QE_FMAN_FW_ADDR
3607 The address in the storage device where the firmware is located. The
3608 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3611 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3612 The maximum possible size of the firmware. The firmware binary format
3613 has a field that specifies the actual size of the firmware, but it
3614 might not be possible to read any part of the firmware unless some
3615 local storage is allocated to hold the entire firmware first.
3617 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3618 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3619 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3620 virtual address in NOR flash.
3622 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3623 Specifies that QE/FMAN firmware is located in NAND flash.
3624 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3626 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3627 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3628 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3630 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3631 Specifies that QE/FMAN firmware is located on the primary SPI
3632 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3634 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3635 Specifies that QE/FMAN firmware is located in the remote (master)
3636 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3637 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3638 window->master inbound window->master LAW->the ucode address in
3639 master's memory space.
3641 Building the Software:
3642 ======================
3644 Building U-Boot has been tested in several native build environments
3645 and in many different cross environments. Of course we cannot support
3646 all possibly existing versions of cross development tools in all
3647 (potentially obsolete) versions. In case of tool chain problems we
3648 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3649 which is extensively used to build and test U-Boot.
3651 If you are not using a native environment, it is assumed that you
3652 have GNU cross compiling tools available in your path. In this case,
3653 you must set the environment variable CROSS_COMPILE in your shell.
3654 Note that no changes to the Makefile or any other source files are
3655 necessary. For example using the ELDK on a 4xx CPU, please enter:
3657 $ CROSS_COMPILE=ppc_4xx-
3658 $ export CROSS_COMPILE
3660 Note: If you wish to generate Windows versions of the utilities in
3661 the tools directory you can use the MinGW toolchain
3662 (http://www.mingw.org). Set your HOST tools to the MinGW
3663 toolchain and execute 'make tools'. For example:
3665 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3667 Binaries such as tools/mkimage.exe will be created which can
3668 be executed on computers running Windows.
3670 U-Boot is intended to be simple to build. After installing the
3671 sources you must configure U-Boot for one specific board type. This
3676 where "NAME_config" is the name of one of the existing configu-
3677 rations; see boards.cfg for supported names.
3679 Note: for some board special configuration names may exist; check if
3680 additional information is available from the board vendor; for
3681 instance, the TQM823L systems are available without (standard)
3682 or with LCD support. You can select such additional "features"
3683 when choosing the configuration, i. e.
3686 - will configure for a plain TQM823L, i. e. no LCD support
3688 make TQM823L_LCD_config
3689 - will configure for a TQM823L with U-Boot console on LCD
3694 Finally, type "make all", and you should get some working U-Boot
3695 images ready for download to / installation on your system:
3697 - "u-boot.bin" is a raw binary image
3698 - "u-boot" is an image in ELF binary format
3699 - "u-boot.srec" is in Motorola S-Record format
3701 By default the build is performed locally and the objects are saved
3702 in the source directory. One of the two methods can be used to change
3703 this behavior and build U-Boot to some external directory:
3705 1. Add O= to the make command line invocations:
3707 make O=/tmp/build distclean
3708 make O=/tmp/build NAME_config
3709 make O=/tmp/build all
3711 2. Set environment variable BUILD_DIR to point to the desired location:
3713 export BUILD_DIR=/tmp/build
3718 Note that the command line "O=" setting overrides the BUILD_DIR environment
3722 Please be aware that the Makefiles assume you are using GNU make, so
3723 for instance on NetBSD you might need to use "gmake" instead of
3727 If the system board that you have is not listed, then you will need
3728 to port U-Boot to your hardware platform. To do this, follow these
3731 1. Add a new configuration option for your board to the toplevel
3732 "boards.cfg" file, using the existing entries as examples.
3733 Follow the instructions there to keep the boards in order.
3734 2. Create a new directory to hold your board specific code. Add any
3735 files you need. In your board directory, you will need at least
3736 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3737 3. Create a new configuration file "include/configs/<board>.h" for
3739 3. If you're porting U-Boot to a new CPU, then also create a new
3740 directory to hold your CPU specific code. Add any files you need.
3741 4. Run "make <board>_config" with your new name.
3742 5. Type "make", and you should get a working "u-boot.srec" file
3743 to be installed on your target system.
3744 6. Debug and solve any problems that might arise.
3745 [Of course, this last step is much harder than it sounds.]
3748 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3749 ==============================================================
3751 If you have modified U-Boot sources (for instance added a new board
3752 or support for new devices, a new CPU, etc.) you are expected to
3753 provide feedback to the other developers. The feedback normally takes
3754 the form of a "patch", i. e. a context diff against a certain (latest
3755 official or latest in the git repository) version of U-Boot sources.
3757 But before you submit such a patch, please verify that your modifi-
3758 cation did not break existing code. At least make sure that *ALL* of
3759 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3760 just run the "MAKEALL" script, which will configure and build U-Boot
3761 for ALL supported system. Be warned, this will take a while. You can
3762 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3763 environment variable to the script, i. e. to use the ELDK cross tools
3766 CROSS_COMPILE=ppc_8xx- MAKEALL
3768 or to build on a native PowerPC system you can type
3770 CROSS_COMPILE=' ' MAKEALL
3772 When using the MAKEALL script, the default behaviour is to build
3773 U-Boot in the source directory. This location can be changed by
3774 setting the BUILD_DIR environment variable. Also, for each target
3775 built, the MAKEALL script saves two log files (<target>.ERR and
3776 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3777 location can be changed by setting the MAKEALL_LOGDIR environment
3778 variable. For example:
3780 export BUILD_DIR=/tmp/build
3781 export MAKEALL_LOGDIR=/tmp/log
3782 CROSS_COMPILE=ppc_8xx- MAKEALL
3784 With the above settings build objects are saved in the /tmp/build,
3785 log files are saved in the /tmp/log and the source tree remains clean
3786 during the whole build process.
3789 See also "U-Boot Porting Guide" below.
3792 Monitor Commands - Overview:
3793 ============================
3795 go - start application at address 'addr'
3796 run - run commands in an environment variable
3797 bootm - boot application image from memory
3798 bootp - boot image via network using BootP/TFTP protocol
3799 bootz - boot zImage from memory
3800 tftpboot- boot image via network using TFTP protocol
3801 and env variables "ipaddr" and "serverip"
3802 (and eventually "gatewayip")
3803 tftpput - upload a file via network using TFTP protocol
3804 rarpboot- boot image via network using RARP/TFTP protocol
3805 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3806 loads - load S-Record file over serial line
3807 loadb - load binary file over serial line (kermit mode)
3809 mm - memory modify (auto-incrementing)
3810 nm - memory modify (constant address)
3811 mw - memory write (fill)
3813 cmp - memory compare
3814 crc32 - checksum calculation
3815 i2c - I2C sub-system
3816 sspi - SPI utility commands
3817 base - print or set address offset
3818 printenv- print environment variables
3819 setenv - set environment variables
3820 saveenv - save environment variables to persistent storage
3821 protect - enable or disable FLASH write protection
3822 erase - erase FLASH memory
3823 flinfo - print FLASH memory information
3824 bdinfo - print Board Info structure
3825 iminfo - print header information for application image
3826 coninfo - print console devices and informations
3827 ide - IDE sub-system
3828 loop - infinite loop on address range
3829 loopw - infinite write loop on address range
3830 mtest - simple RAM test
3831 icache - enable or disable instruction cache
3832 dcache - enable or disable data cache
3833 reset - Perform RESET of the CPU
3834 echo - echo args to console
3835 version - print monitor version
3836 help - print online help
3837 ? - alias for 'help'
3840 Monitor Commands - Detailed Description:
3841 ========================================
3845 For now: just type "help <command>".
3848 Environment Variables:
3849 ======================
3851 U-Boot supports user configuration using Environment Variables which
3852 can be made persistent by saving to Flash memory.
3854 Environment Variables are set using "setenv", printed using
3855 "printenv", and saved to Flash using "saveenv". Using "setenv"
3856 without a value can be used to delete a variable from the
3857 environment. As long as you don't save the environment you are
3858 working with an in-memory copy. In case the Flash area containing the
3859 environment is erased by accident, a default environment is provided.
3861 Some configuration options can be set using Environment Variables.
3863 List of environment variables (most likely not complete):
3865 baudrate - see CONFIG_BAUDRATE
3867 bootdelay - see CONFIG_BOOTDELAY
3869 bootcmd - see CONFIG_BOOTCOMMAND
3871 bootargs - Boot arguments when booting an RTOS image
3873 bootfile - Name of the image to load with TFTP
3875 bootm_low - Memory range available for image processing in the bootm
3876 command can be restricted. This variable is given as
3877 a hexadecimal number and defines lowest address allowed
3878 for use by the bootm command. See also "bootm_size"
3879 environment variable. Address defined by "bootm_low" is
3880 also the base of the initial memory mapping for the Linux
3881 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3884 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3885 This variable is given as a hexadecimal number and it
3886 defines the size of the memory region starting at base
3887 address bootm_low that is accessible by the Linux kernel
3888 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3889 as the default value if it is defined, and bootm_size is
3892 bootm_size - Memory range available for image processing in the bootm
3893 command can be restricted. This variable is given as
3894 a hexadecimal number and defines the size of the region
3895 allowed for use by the bootm command. See also "bootm_low"
3896 environment variable.
3898 updatefile - Location of the software update file on a TFTP server, used
3899 by the automatic software update feature. Please refer to
3900 documentation in doc/README.update for more details.
3902 autoload - if set to "no" (any string beginning with 'n'),
3903 "bootp" will just load perform a lookup of the
3904 configuration from the BOOTP server, but not try to
3905 load any image using TFTP
3907 autostart - if set to "yes", an image loaded using the "bootp",
3908 "rarpboot", "tftpboot" or "diskboot" commands will
3909 be automatically started (by internally calling
3912 If set to "no", a standalone image passed to the
3913 "bootm" command will be copied to the load address
3914 (and eventually uncompressed), but NOT be started.
3915 This can be used to load and uncompress arbitrary
3918 fdt_high - if set this restricts the maximum address that the
3919 flattened device tree will be copied into upon boot.
3920 For example, if you have a system with 1 GB memory
3921 at physical address 0x10000000, while Linux kernel
3922 only recognizes the first 704 MB as low memory, you
3923 may need to set fdt_high as 0x3C000000 to have the
3924 device tree blob be copied to the maximum address
3925 of the 704 MB low memory, so that Linux kernel can
3926 access it during the boot procedure.
3928 If this is set to the special value 0xFFFFFFFF then
3929 the fdt will not be copied at all on boot. For this
3930 to work it must reside in writable memory, have
3931 sufficient padding on the end of it for u-boot to
3932 add the information it needs into it, and the memory
3933 must be accessible by the kernel.
3935 fdtcontroladdr- if set this is the address of the control flattened
3936 device tree used by U-Boot when CONFIG_OF_CONTROL is
3939 i2cfast - (PPC405GP|PPC405EP only)
3940 if set to 'y' configures Linux I2C driver for fast
3941 mode (400kHZ). This environment variable is used in
3942 initialization code. So, for changes to be effective
3943 it must be saved and board must be reset.
3945 initrd_high - restrict positioning of initrd images:
3946 If this variable is not set, initrd images will be
3947 copied to the highest possible address in RAM; this
3948 is usually what you want since it allows for
3949 maximum initrd size. If for some reason you want to
3950 make sure that the initrd image is loaded below the
3951 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3952 variable to a value of "no" or "off" or "0".
3953 Alternatively, you can set it to a maximum upper
3954 address to use (U-Boot will still check that it
3955 does not overwrite the U-Boot stack and data).
3957 For instance, when you have a system with 16 MB
3958 RAM, and want to reserve 4 MB from use by Linux,
3959 you can do this by adding "mem=12M" to the value of
3960 the "bootargs" variable. However, now you must make
3961 sure that the initrd image is placed in the first
3962 12 MB as well - this can be done with
3964 setenv initrd_high 00c00000
3966 If you set initrd_high to 0xFFFFFFFF, this is an
3967 indication to U-Boot that all addresses are legal
3968 for the Linux kernel, including addresses in flash
3969 memory. In this case U-Boot will NOT COPY the
3970 ramdisk at all. This may be useful to reduce the
3971 boot time on your system, but requires that this
3972 feature is supported by your Linux kernel.
3974 ipaddr - IP address; needed for tftpboot command
3976 loadaddr - Default load address for commands like "bootp",
3977 "rarpboot", "tftpboot", "loadb" or "diskboot"
3979 loads_echo - see CONFIG_LOADS_ECHO
3981 serverip - TFTP server IP address; needed for tftpboot command
3983 bootretry - see CONFIG_BOOT_RETRY_TIME
3985 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3987 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3989 ethprime - controls which interface is used first.
3991 ethact - controls which interface is currently active.
3992 For example you can do the following
3994 => setenv ethact FEC
3995 => ping 192.168.0.1 # traffic sent on FEC
3996 => setenv ethact SCC
3997 => ping 10.0.0.1 # traffic sent on SCC
3999 ethrotate - When set to "no" U-Boot does not go through all
4000 available network interfaces.
4001 It just stays at the currently selected interface.
4003 netretry - When set to "no" each network operation will
4004 either succeed or fail without retrying.
4005 When set to "once" the network operation will
4006 fail when all the available network interfaces
4007 are tried once without success.
4008 Useful on scripts which control the retry operation
4011 npe_ucode - set load address for the NPE microcode
4013 tftpsrcport - If this is set, the value is used for TFTP's
4016 tftpdstport - If this is set, the value is used for TFTP's UDP
4017 destination port instead of the Well Know Port 69.
4019 tftpblocksize - Block size to use for TFTP transfers; if not set,
4020 we use the TFTP server's default block size
4022 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4023 seconds, minimum value is 1000 = 1 second). Defines
4024 when a packet is considered to be lost so it has to
4025 be retransmitted. The default is 5000 = 5 seconds.
4026 Lowering this value may make downloads succeed
4027 faster in networks with high packet loss rates or
4028 with unreliable TFTP servers.
4030 vlan - When set to a value < 4095 the traffic over
4031 Ethernet is encapsulated/received over 802.1q
4034 The following image location variables contain the location of images
4035 used in booting. The "Image" column gives the role of the image and is
4036 not an environment variable name. The other columns are environment
4037 variable names. "File Name" gives the name of the file on a TFTP
4038 server, "RAM Address" gives the location in RAM the image will be
4039 loaded to, and "Flash Location" gives the image's address in NOR
4040 flash or offset in NAND flash.
4042 *Note* - these variables don't have to be defined for all boards, some
4043 boards currenlty use other variables for these purposes, and some
4044 boards use these variables for other purposes.
4046 Image File Name RAM Address Flash Location
4047 ----- --------- ----------- --------------
4048 u-boot u-boot u-boot_addr_r u-boot_addr
4049 Linux kernel bootfile kernel_addr_r kernel_addr
4050 device tree blob fdtfile fdt_addr_r fdt_addr
4051 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4053 The following environment variables may be used and automatically
4054 updated by the network boot commands ("bootp" and "rarpboot"),
4055 depending the information provided by your boot server:
4057 bootfile - see above
4058 dnsip - IP address of your Domain Name Server
4059 dnsip2 - IP address of your secondary Domain Name Server
4060 gatewayip - IP address of the Gateway (Router) to use
4061 hostname - Target hostname
4063 netmask - Subnet Mask
4064 rootpath - Pathname of the root filesystem on the NFS server
4065 serverip - see above
4068 There are two special Environment Variables:
4070 serial# - contains hardware identification information such
4071 as type string and/or serial number
4072 ethaddr - Ethernet address
4074 These variables can be set only once (usually during manufacturing of
4075 the board). U-Boot refuses to delete or overwrite these variables
4076 once they have been set once.
4079 Further special Environment Variables:
4081 ver - Contains the U-Boot version string as printed
4082 with the "version" command. This variable is
4083 readonly (see CONFIG_VERSION_VARIABLE).
4086 Please note that changes to some configuration parameters may take
4087 only effect after the next boot (yes, that's just like Windoze :-).
4090 Command Line Parsing:
4091 =====================
4093 There are two different command line parsers available with U-Boot:
4094 the old "simple" one, and the much more powerful "hush" shell:
4096 Old, simple command line parser:
4097 --------------------------------
4099 - supports environment variables (through setenv / saveenv commands)
4100 - several commands on one line, separated by ';'
4101 - variable substitution using "... ${name} ..." syntax
4102 - special characters ('$', ';') can be escaped by prefixing with '\',
4104 setenv bootcmd bootm \${address}
4105 - You can also escape text by enclosing in single apostrophes, for example:
4106 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4111 - similar to Bourne shell, with control structures like
4112 if...then...else...fi, for...do...done; while...do...done,
4113 until...do...done, ...
4114 - supports environment ("global") variables (through setenv / saveenv
4115 commands) and local shell variables (through standard shell syntax
4116 "name=value"); only environment variables can be used with "run"
4122 (1) If a command line (or an environment variable executed by a "run"
4123 command) contains several commands separated by semicolon, and
4124 one of these commands fails, then the remaining commands will be
4127 (2) If you execute several variables with one call to run (i. e.
4128 calling run with a list of variables as arguments), any failing
4129 command will cause "run" to terminate, i. e. the remaining
4130 variables are not executed.
4132 Note for Redundant Ethernet Interfaces:
4133 =======================================
4135 Some boards come with redundant Ethernet interfaces; U-Boot supports
4136 such configurations and is capable of automatic selection of a
4137 "working" interface when needed. MAC assignment works as follows:
4139 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4140 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4141 "eth1addr" (=>eth1), "eth2addr", ...
4143 If the network interface stores some valid MAC address (for instance
4144 in SROM), this is used as default address if there is NO correspon-
4145 ding setting in the environment; if the corresponding environment
4146 variable is set, this overrides the settings in the card; that means:
4148 o If the SROM has a valid MAC address, and there is no address in the
4149 environment, the SROM's address is used.
4151 o If there is no valid address in the SROM, and a definition in the
4152 environment exists, then the value from the environment variable is
4155 o If both the SROM and the environment contain a MAC address, and
4156 both addresses are the same, this MAC address is used.
4158 o If both the SROM and the environment contain a MAC address, and the
4159 addresses differ, the value from the environment is used and a
4162 o If neither SROM nor the environment contain a MAC address, an error
4165 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4166 will be programmed into hardware as part of the initialization process. This
4167 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4168 The naming convention is as follows:
4169 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4174 U-Boot is capable of booting (and performing other auxiliary operations on)
4175 images in two formats:
4177 New uImage format (FIT)
4178 -----------------------
4180 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4181 to Flattened Device Tree). It allows the use of images with multiple
4182 components (several kernels, ramdisks, etc.), with contents protected by
4183 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4189 Old image format is based on binary files which can be basically anything,
4190 preceded by a special header; see the definitions in include/image.h for
4191 details; basically, the header defines the following image properties:
4193 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4194 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4195 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4196 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4198 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4199 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4200 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4201 * Compression Type (uncompressed, gzip, bzip2)
4207 The header is marked by a special Magic Number, and both the header
4208 and the data portions of the image are secured against corruption by
4215 Although U-Boot should support any OS or standalone application
4216 easily, the main focus has always been on Linux during the design of
4219 U-Boot includes many features that so far have been part of some
4220 special "boot loader" code within the Linux kernel. Also, any
4221 "initrd" images to be used are no longer part of one big Linux image;
4222 instead, kernel and "initrd" are separate images. This implementation
4223 serves several purposes:
4225 - the same features can be used for other OS or standalone
4226 applications (for instance: using compressed images to reduce the
4227 Flash memory footprint)
4229 - it becomes much easier to port new Linux kernel versions because
4230 lots of low-level, hardware dependent stuff are done by U-Boot
4232 - the same Linux kernel image can now be used with different "initrd"
4233 images; of course this also means that different kernel images can
4234 be run with the same "initrd". This makes testing easier (you don't
4235 have to build a new "zImage.initrd" Linux image when you just
4236 change a file in your "initrd"). Also, a field-upgrade of the
4237 software is easier now.
4243 Porting Linux to U-Boot based systems:
4244 ---------------------------------------
4246 U-Boot cannot save you from doing all the necessary modifications to
4247 configure the Linux device drivers for use with your target hardware
4248 (no, we don't intend to provide a full virtual machine interface to
4251 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4253 Just make sure your machine specific header file (for instance
4254 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4255 Information structure as we define in include/asm-<arch>/u-boot.h,
4256 and make sure that your definition of IMAP_ADDR uses the same value
4257 as your U-Boot configuration in CONFIG_SYS_IMMR.
4260 Configuring the Linux kernel:
4261 -----------------------------
4263 No specific requirements for U-Boot. Make sure you have some root
4264 device (initial ramdisk, NFS) for your target system.
4267 Building a Linux Image:
4268 -----------------------
4270 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4271 not used. If you use recent kernel source, a new build target
4272 "uImage" will exist which automatically builds an image usable by
4273 U-Boot. Most older kernels also have support for a "pImage" target,
4274 which was introduced for our predecessor project PPCBoot and uses a
4275 100% compatible format.
4284 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4285 encapsulate a compressed Linux kernel image with header information,
4286 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4288 * build a standard "vmlinux" kernel image (in ELF binary format):
4290 * convert the kernel into a raw binary image:
4292 ${CROSS_COMPILE}-objcopy -O binary \
4293 -R .note -R .comment \
4294 -S vmlinux linux.bin
4296 * compress the binary image:
4300 * package compressed binary image for U-Boot:
4302 mkimage -A ppc -O linux -T kernel -C gzip \
4303 -a 0 -e 0 -n "Linux Kernel Image" \
4304 -d linux.bin.gz uImage
4307 The "mkimage" tool can also be used to create ramdisk images for use
4308 with U-Boot, either separated from the Linux kernel image, or
4309 combined into one file. "mkimage" encapsulates the images with a 64
4310 byte header containing information about target architecture,
4311 operating system, image type, compression method, entry points, time
4312 stamp, CRC32 checksums, etc.
4314 "mkimage" can be called in two ways: to verify existing images and
4315 print the header information, or to build new images.
4317 In the first form (with "-l" option) mkimage lists the information
4318 contained in the header of an existing U-Boot image; this includes
4319 checksum verification:
4321 tools/mkimage -l image
4322 -l ==> list image header information
4324 The second form (with "-d" option) is used to build a U-Boot image
4325 from a "data file" which is used as image payload:
4327 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4328 -n name -d data_file image
4329 -A ==> set architecture to 'arch'
4330 -O ==> set operating system to 'os'
4331 -T ==> set image type to 'type'
4332 -C ==> set compression type 'comp'
4333 -a ==> set load address to 'addr' (hex)
4334 -e ==> set entry point to 'ep' (hex)
4335 -n ==> set image name to 'name'
4336 -d ==> use image data from 'datafile'
4338 Right now, all Linux kernels for PowerPC systems use the same load
4339 address (0x00000000), but the entry point address depends on the
4342 - 2.2.x kernels have the entry point at 0x0000000C,
4343 - 2.3.x and later kernels have the entry point at 0x00000000.
4345 So a typical call to build a U-Boot image would read:
4347 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4348 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4349 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4350 > examples/uImage.TQM850L
4351 Image Name: 2.4.4 kernel for TQM850L
4352 Created: Wed Jul 19 02:34:59 2000
4353 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4354 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4355 Load Address: 0x00000000
4356 Entry Point: 0x00000000
4358 To verify the contents of the image (or check for corruption):
4360 -> tools/mkimage -l examples/uImage.TQM850L
4361 Image Name: 2.4.4 kernel for TQM850L
4362 Created: Wed Jul 19 02:34:59 2000
4363 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4364 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4365 Load Address: 0x00000000
4366 Entry Point: 0x00000000
4368 NOTE: for embedded systems where boot time is critical you can trade
4369 speed for memory and install an UNCOMPRESSED image instead: this
4370 needs more space in Flash, but boots much faster since it does not
4371 need to be uncompressed:
4373 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4374 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4375 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4376 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4377 > examples/uImage.TQM850L-uncompressed
4378 Image Name: 2.4.4 kernel for TQM850L
4379 Created: Wed Jul 19 02:34:59 2000
4380 Image Type: PowerPC Linux Kernel Image (uncompressed)
4381 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4382 Load Address: 0x00000000
4383 Entry Point: 0x00000000
4386 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4387 when your kernel is intended to use an initial ramdisk:
4389 -> tools/mkimage -n 'Simple Ramdisk Image' \
4390 > -A ppc -O linux -T ramdisk -C gzip \
4391 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4392 Image Name: Simple Ramdisk Image
4393 Created: Wed Jan 12 14:01:50 2000
4394 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4395 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4396 Load Address: 0x00000000
4397 Entry Point: 0x00000000
4400 Installing a Linux Image:
4401 -------------------------
4403 To downloading a U-Boot image over the serial (console) interface,
4404 you must convert the image to S-Record format:
4406 objcopy -I binary -O srec examples/image examples/image.srec
4408 The 'objcopy' does not understand the information in the U-Boot
4409 image header, so the resulting S-Record file will be relative to
4410 address 0x00000000. To load it to a given address, you need to
4411 specify the target address as 'offset' parameter with the 'loads'
4414 Example: install the image to address 0x40100000 (which on the
4415 TQM8xxL is in the first Flash bank):
4417 => erase 40100000 401FFFFF
4423 ## Ready for S-Record download ...
4424 ~>examples/image.srec
4425 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4427 15989 15990 15991 15992
4428 [file transfer complete]
4430 ## Start Addr = 0x00000000
4433 You can check the success of the download using the 'iminfo' command;
4434 this includes a checksum verification so you can be sure no data
4435 corruption happened:
4439 ## Checking Image at 40100000 ...
4440 Image Name: 2.2.13 for initrd on TQM850L
4441 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4442 Data Size: 335725 Bytes = 327 kB = 0 MB
4443 Load Address: 00000000
4444 Entry Point: 0000000c
4445 Verifying Checksum ... OK
4451 The "bootm" command is used to boot an application that is stored in
4452 memory (RAM or Flash). In case of a Linux kernel image, the contents
4453 of the "bootargs" environment variable is passed to the kernel as
4454 parameters. You can check and modify this variable using the
4455 "printenv" and "setenv" commands:
4458 => printenv bootargs
4459 bootargs=root=/dev/ram
4461 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4463 => printenv bootargs
4464 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4467 ## Booting Linux kernel at 40020000 ...
4468 Image Name: 2.2.13 for NFS on TQM850L
4469 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4470 Data Size: 381681 Bytes = 372 kB = 0 MB
4471 Load Address: 00000000
4472 Entry Point: 0000000c
4473 Verifying Checksum ... OK
4474 Uncompressing Kernel Image ... OK
4475 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
4476 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4477 time_init: decrementer frequency = 187500000/60
4478 Calibrating delay loop... 49.77 BogoMIPS
4479 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4482 If you want to boot a Linux kernel with initial RAM disk, you pass
4483 the memory addresses of both the kernel and the initrd image (PPBCOOT
4484 format!) to the "bootm" command:
4486 => imi 40100000 40200000
4488 ## Checking Image at 40100000 ...
4489 Image Name: 2.2.13 for initrd on TQM850L
4490 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4491 Data Size: 335725 Bytes = 327 kB = 0 MB
4492 Load Address: 00000000
4493 Entry Point: 0000000c
4494 Verifying Checksum ... OK
4496 ## Checking Image at 40200000 ...
4497 Image Name: Simple Ramdisk Image
4498 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4499 Data Size: 566530 Bytes = 553 kB = 0 MB
4500 Load Address: 00000000
4501 Entry Point: 00000000
4502 Verifying Checksum ... OK
4504 => bootm 40100000 40200000
4505 ## Booting Linux kernel at 40100000 ...
4506 Image Name: 2.2.13 for initrd on TQM850L
4507 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4508 Data Size: 335725 Bytes = 327 kB = 0 MB
4509 Load Address: 00000000
4510 Entry Point: 0000000c
4511 Verifying Checksum ... OK
4512 Uncompressing Kernel Image ... OK
4513 ## Loading RAMDisk Image at 40200000 ...
4514 Image Name: Simple Ramdisk Image
4515 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4516 Data Size: 566530 Bytes = 553 kB = 0 MB
4517 Load Address: 00000000
4518 Entry Point: 00000000
4519 Verifying Checksum ... OK
4520 Loading Ramdisk ... OK
4521 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
4522 Boot arguments: root=/dev/ram
4523 time_init: decrementer frequency = 187500000/60
4524 Calibrating delay loop... 49.77 BogoMIPS
4526 RAMDISK: Compressed image found at block 0
4527 VFS: Mounted root (ext2 filesystem).
4531 Boot Linux and pass a flat device tree:
4534 First, U-Boot must be compiled with the appropriate defines. See the section
4535 titled "Linux Kernel Interface" above for a more in depth explanation. The
4536 following is an example of how to start a kernel and pass an updated
4542 oft=oftrees/mpc8540ads.dtb
4543 => tftp $oftaddr $oft
4544 Speed: 1000, full duplex
4546 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4547 Filename 'oftrees/mpc8540ads.dtb'.
4548 Load address: 0x300000
4551 Bytes transferred = 4106 (100a hex)
4552 => tftp $loadaddr $bootfile
4553 Speed: 1000, full duplex
4555 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4557 Load address: 0x200000
4558 Loading:############
4560 Bytes transferred = 1029407 (fb51f hex)
4565 => bootm $loadaddr - $oftaddr
4566 ## Booting image at 00200000 ...
4567 Image Name: Linux-2.6.17-dirty
4568 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4569 Data Size: 1029343 Bytes = 1005.2 kB
4570 Load Address: 00000000
4571 Entry Point: 00000000
4572 Verifying Checksum ... OK
4573 Uncompressing Kernel Image ... OK
4574 Booting using flat device tree at 0x300000
4575 Using MPC85xx ADS machine description
4576 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4580 More About U-Boot Image Types:
4581 ------------------------------
4583 U-Boot supports the following image types:
4585 "Standalone Programs" are directly runnable in the environment
4586 provided by U-Boot; it is expected that (if they behave
4587 well) you can continue to work in U-Boot after return from
4588 the Standalone Program.
4589 "OS Kernel Images" are usually images of some Embedded OS which
4590 will take over control completely. Usually these programs
4591 will install their own set of exception handlers, device
4592 drivers, set up the MMU, etc. - this means, that you cannot
4593 expect to re-enter U-Boot except by resetting the CPU.
4594 "RAMDisk Images" are more or less just data blocks, and their
4595 parameters (address, size) are passed to an OS kernel that is
4597 "Multi-File Images" contain several images, typically an OS
4598 (Linux) kernel image and one or more data images like
4599 RAMDisks. This construct is useful for instance when you want
4600 to boot over the network using BOOTP etc., where the boot
4601 server provides just a single image file, but you want to get
4602 for instance an OS kernel and a RAMDisk image.
4604 "Multi-File Images" start with a list of image sizes, each
4605 image size (in bytes) specified by an "uint32_t" in network
4606 byte order. This list is terminated by an "(uint32_t)0".
4607 Immediately after the terminating 0 follow the images, one by
4608 one, all aligned on "uint32_t" boundaries (size rounded up to
4609 a multiple of 4 bytes).
4611 "Firmware Images" are binary images containing firmware (like
4612 U-Boot or FPGA images) which usually will be programmed to
4615 "Script files" are command sequences that will be executed by
4616 U-Boot's command interpreter; this feature is especially
4617 useful when you configure U-Boot to use a real shell (hush)
4618 as command interpreter.
4620 Booting the Linux zImage:
4621 -------------------------
4623 On some platforms, it's possible to boot Linux zImage. This is done
4624 using the "bootz" command. The syntax of "bootz" command is the same
4625 as the syntax of "bootm" command.
4627 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4628 kernel with raw initrd images. The syntax is slightly different, the
4629 address of the initrd must be augmented by it's size, in the following
4630 format: "<initrd addres>:<initrd size>".
4636 One of the features of U-Boot is that you can dynamically load and
4637 run "standalone" applications, which can use some resources of
4638 U-Boot like console I/O functions or interrupt services.
4640 Two simple examples are included with the sources:
4645 'examples/hello_world.c' contains a small "Hello World" Demo
4646 application; it is automatically compiled when you build U-Boot.
4647 It's configured to run at address 0x00040004, so you can play with it
4651 ## Ready for S-Record download ...
4652 ~>examples/hello_world.srec
4653 1 2 3 4 5 6 7 8 9 10 11 ...
4654 [file transfer complete]
4656 ## Start Addr = 0x00040004
4658 => go 40004 Hello World! This is a test.
4659 ## Starting application at 0x00040004 ...
4670 Hit any key to exit ...
4672 ## Application terminated, rc = 0x0
4674 Another example, which demonstrates how to register a CPM interrupt
4675 handler with the U-Boot code, can be found in 'examples/timer.c'.
4676 Here, a CPM timer is set up to generate an interrupt every second.
4677 The interrupt service routine is trivial, just printing a '.'
4678 character, but this is just a demo program. The application can be
4679 controlled by the following keys:
4681 ? - print current values og the CPM Timer registers
4682 b - enable interrupts and start timer
4683 e - stop timer and disable interrupts
4684 q - quit application
4687 ## Ready for S-Record download ...
4688 ~>examples/timer.srec
4689 1 2 3 4 5 6 7 8 9 10 11 ...
4690 [file transfer complete]
4692 ## Start Addr = 0x00040004
4695 ## Starting application at 0x00040004 ...
4698 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4701 [q, b, e, ?] Set interval 1000000 us
4704 [q, b, e, ?] ........
4705 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4708 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4711 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4714 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4716 [q, b, e, ?] ...Stopping timer
4718 [q, b, e, ?] ## Application terminated, rc = 0x0
4724 Over time, many people have reported problems when trying to use the
4725 "minicom" terminal emulation program for serial download. I (wd)
4726 consider minicom to be broken, and recommend not to use it. Under
4727 Unix, I recommend to use C-Kermit for general purpose use (and
4728 especially for kermit binary protocol download ("loadb" command), and
4729 use "cu" for S-Record download ("loads" command). See
4730 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4731 for help with kermit.
4734 Nevertheless, if you absolutely want to use it try adding this
4735 configuration to your "File transfer protocols" section:
4737 Name Program Name U/D FullScr IO-Red. Multi
4738 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4739 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4745 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4746 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4748 Building requires a cross environment; it is known to work on
4749 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4750 need gmake since the Makefiles are not compatible with BSD make).
4751 Note that the cross-powerpc package does not install include files;
4752 attempting to build U-Boot will fail because <machine/ansi.h> is
4753 missing. This file has to be installed and patched manually:
4755 # cd /usr/pkg/cross/powerpc-netbsd/include
4757 # ln -s powerpc machine
4758 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4759 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4761 Native builds *don't* work due to incompatibilities between native
4762 and U-Boot include files.
4764 Booting assumes that (the first part of) the image booted is a
4765 stage-2 loader which in turn loads and then invokes the kernel
4766 proper. Loader sources will eventually appear in the NetBSD source
4767 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4768 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4771 Implementation Internals:
4772 =========================
4774 The following is not intended to be a complete description of every
4775 implementation detail. However, it should help to understand the
4776 inner workings of U-Boot and make it easier to port it to custom
4780 Initial Stack, Global Data:
4781 ---------------------------
4783 The implementation of U-Boot is complicated by the fact that U-Boot
4784 starts running out of ROM (flash memory), usually without access to
4785 system RAM (because the memory controller is not initialized yet).
4786 This means that we don't have writable Data or BSS segments, and BSS
4787 is not initialized as zero. To be able to get a C environment working
4788 at all, we have to allocate at least a minimal stack. Implementation
4789 options for this are defined and restricted by the CPU used: Some CPU
4790 models provide on-chip memory (like the IMMR area on MPC8xx and
4791 MPC826x processors), on others (parts of) the data cache can be
4792 locked as (mis-) used as memory, etc.
4794 Chris Hallinan posted a good summary of these issues to the
4795 U-Boot mailing list:
4797 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4798 From: "Chris Hallinan" <clh@net1plus.com>
4799 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4802 Correct me if I'm wrong, folks, but the way I understand it
4803 is this: Using DCACHE as initial RAM for Stack, etc, does not
4804 require any physical RAM backing up the cache. The cleverness
4805 is that the cache is being used as a temporary supply of
4806 necessary storage before the SDRAM controller is setup. It's
4807 beyond the scope of this list to explain the details, but you
4808 can see how this works by studying the cache architecture and
4809 operation in the architecture and processor-specific manuals.
4811 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4812 is another option for the system designer to use as an
4813 initial stack/RAM area prior to SDRAM being available. Either
4814 option should work for you. Using CS 4 should be fine if your
4815 board designers haven't used it for something that would
4816 cause you grief during the initial boot! It is frequently not
4819 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4820 with your processor/board/system design. The default value
4821 you will find in any recent u-boot distribution in
4822 walnut.h should work for you. I'd set it to a value larger
4823 than your SDRAM module. If you have a 64MB SDRAM module, set
4824 it above 400_0000. Just make sure your board has no resources
4825 that are supposed to respond to that address! That code in
4826 start.S has been around a while and should work as is when
4827 you get the config right.
4832 It is essential to remember this, since it has some impact on the C
4833 code for the initialization procedures:
4835 * Initialized global data (data segment) is read-only. Do not attempt
4838 * Do not use any uninitialized global data (or implicitely initialized
4839 as zero data - BSS segment) at all - this is undefined, initiali-
4840 zation is performed later (when relocating to RAM).
4842 * Stack space is very limited. Avoid big data buffers or things like
4845 Having only the stack as writable memory limits means we cannot use
4846 normal global data to share information beween the code. But it
4847 turned out that the implementation of U-Boot can be greatly
4848 simplified by making a global data structure (gd_t) available to all
4849 functions. We could pass a pointer to this data as argument to _all_
4850 functions, but this would bloat the code. Instead we use a feature of
4851 the GCC compiler (Global Register Variables) to share the data: we
4852 place a pointer (gd) to the global data into a register which we
4853 reserve for this purpose.
4855 When choosing a register for such a purpose we are restricted by the
4856 relevant (E)ABI specifications for the current architecture, and by
4857 GCC's implementation.
4859 For PowerPC, the following registers have specific use:
4861 R2: reserved for system use
4862 R3-R4: parameter passing and return values
4863 R5-R10: parameter passing
4864 R13: small data area pointer
4868 (U-Boot also uses R12 as internal GOT pointer. r12
4869 is a volatile register so r12 needs to be reset when
4870 going back and forth between asm and C)
4872 ==> U-Boot will use R2 to hold a pointer to the global data
4874 Note: on PPC, we could use a static initializer (since the
4875 address of the global data structure is known at compile time),
4876 but it turned out that reserving a register results in somewhat
4877 smaller code - although the code savings are not that big (on
4878 average for all boards 752 bytes for the whole U-Boot image,
4879 624 text + 127 data).
4881 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4882 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4884 ==> U-Boot will use P3 to hold a pointer to the global data
4886 On ARM, the following registers are used:
4888 R0: function argument word/integer result
4889 R1-R3: function argument word
4891 R10: stack limit (used only if stack checking if enabled)
4892 R11: argument (frame) pointer
4893 R12: temporary workspace
4896 R15: program counter
4898 ==> U-Boot will use R8 to hold a pointer to the global data
4900 On Nios II, the ABI is documented here:
4901 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4903 ==> U-Boot will use gp to hold a pointer to the global data
4905 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4906 to access small data sections, so gp is free.
4908 On NDS32, the following registers are used:
4910 R0-R1: argument/return
4912 R15: temporary register for assembler
4913 R16: trampoline register
4914 R28: frame pointer (FP)
4915 R29: global pointer (GP)
4916 R30: link register (LP)
4917 R31: stack pointer (SP)
4918 PC: program counter (PC)
4920 ==> U-Boot will use R10 to hold a pointer to the global data
4922 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4923 or current versions of GCC may "optimize" the code too much.
4928 U-Boot runs in system state and uses physical addresses, i.e. the
4929 MMU is not used either for address mapping nor for memory protection.
4931 The available memory is mapped to fixed addresses using the memory
4932 controller. In this process, a contiguous block is formed for each
4933 memory type (Flash, SDRAM, SRAM), even when it consists of several
4934 physical memory banks.
4936 U-Boot is installed in the first 128 kB of the first Flash bank (on
4937 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4938 booting and sizing and initializing DRAM, the code relocates itself
4939 to the upper end of DRAM. Immediately below the U-Boot code some
4940 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4941 configuration setting]. Below that, a structure with global Board
4942 Info data is placed, followed by the stack (growing downward).
4944 Additionally, some exception handler code is copied to the low 8 kB
4945 of DRAM (0x00000000 ... 0x00001FFF).
4947 So a typical memory configuration with 16 MB of DRAM could look like
4950 0x0000 0000 Exception Vector code
4953 0x0000 2000 Free for Application Use
4959 0x00FB FF20 Monitor Stack (Growing downward)
4960 0x00FB FFAC Board Info Data and permanent copy of global data
4961 0x00FC 0000 Malloc Arena
4964 0x00FE 0000 RAM Copy of Monitor Code
4965 ... eventually: LCD or video framebuffer
4966 ... eventually: pRAM (Protected RAM - unchanged by reset)
4967 0x00FF FFFF [End of RAM]
4970 System Initialization:
4971 ----------------------
4973 In the reset configuration, U-Boot starts at the reset entry point
4974 (on most PowerPC systems at address 0x00000100). Because of the reset
4975 configuration for CS0# this is a mirror of the onboard Flash memory.
4976 To be able to re-map memory U-Boot then jumps to its link address.
4977 To be able to implement the initialization code in C, a (small!)
4978 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4979 which provide such a feature like MPC8xx or MPC8260), or in a locked
4980 part of the data cache. After that, U-Boot initializes the CPU core,
4981 the caches and the SIU.
4983 Next, all (potentially) available memory banks are mapped using a
4984 preliminary mapping. For example, we put them on 512 MB boundaries
4985 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4986 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4987 programmed for SDRAM access. Using the temporary configuration, a
4988 simple memory test is run that determines the size of the SDRAM
4991 When there is more than one SDRAM bank, and the banks are of
4992 different size, the largest is mapped first. For equal size, the first
4993 bank (CS2#) is mapped first. The first mapping is always for address
4994 0x00000000, with any additional banks following immediately to create
4995 contiguous memory starting from 0.
4997 Then, the monitor installs itself at the upper end of the SDRAM area
4998 and allocates memory for use by malloc() and for the global Board
4999 Info data; also, the exception vector code is copied to the low RAM
5000 pages, and the final stack is set up.
5002 Only after this relocation will you have a "normal" C environment;
5003 until that you are restricted in several ways, mostly because you are
5004 running from ROM, and because the code will have to be relocated to a
5008 U-Boot Porting Guide:
5009 ----------------------
5011 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5015 int main(int argc, char *argv[])
5017 sighandler_t no_more_time;
5019 signal(SIGALRM, no_more_time);
5020 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5022 if (available_money > available_manpower) {
5023 Pay consultant to port U-Boot;
5027 Download latest U-Boot source;
5029 Subscribe to u-boot mailing list;
5032 email("Hi, I am new to U-Boot, how do I get started?");
5035 Read the README file in the top level directory;
5036 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5037 Read applicable doc/*.README;
5038 Read the source, Luke;
5039 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5042 if (available_money > toLocalCurrency ($2500))
5045 Add a lot of aggravation and time;
5047 if (a similar board exists) { /* hopefully... */
5048 cp -a board/<similar> board/<myboard>
5049 cp include/configs/<similar>.h include/configs/<myboard>.h
5051 Create your own board support subdirectory;
5052 Create your own board include/configs/<myboard>.h file;
5054 Edit new board/<myboard> files
5055 Edit new include/configs/<myboard>.h
5060 Add / modify source code;
5064 email("Hi, I am having problems...");
5066 Send patch file to the U-Boot email list;
5067 if (reasonable critiques)
5068 Incorporate improvements from email list code review;
5070 Defend code as written;
5076 void no_more_time (int sig)
5085 All contributions to U-Boot should conform to the Linux kernel
5086 coding style; see the file "Documentation/CodingStyle" and the script
5087 "scripts/Lindent" in your Linux kernel source directory.
5089 Source files originating from a different project (for example the
5090 MTD subsystem) are generally exempt from these guidelines and are not
5091 reformated to ease subsequent migration to newer versions of those
5094 Please note that U-Boot is implemented in C (and to some small parts in
5095 Assembler); no C++ is used, so please do not use C++ style comments (//)
5098 Please also stick to the following formatting rules:
5099 - remove any trailing white space
5100 - use TAB characters for indentation and vertical alignment, not spaces
5101 - make sure NOT to use DOS '\r\n' line feeds
5102 - do not add more than 2 consecutive empty lines to source files
5103 - do not add trailing empty lines to source files
5105 Submissions which do not conform to the standards may be returned
5106 with a request to reformat the changes.
5112 Since the number of patches for U-Boot is growing, we need to
5113 establish some rules. Submissions which do not conform to these rules
5114 may be rejected, even when they contain important and valuable stuff.
5116 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5118 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5119 see http://lists.denx.de/mailman/listinfo/u-boot
5121 When you send a patch, please include the following information with
5124 * For bug fixes: a description of the bug and how your patch fixes
5125 this bug. Please try to include a way of demonstrating that the
5126 patch actually fixes something.
5128 * For new features: a description of the feature and your
5131 * A CHANGELOG entry as plaintext (separate from the patch)
5133 * For major contributions, your entry to the CREDITS file
5135 * When you add support for a new board, don't forget to add this
5136 board to the MAINTAINERS file, too.
5138 * If your patch adds new configuration options, don't forget to
5139 document these in the README file.
5141 * The patch itself. If you are using git (which is *strongly*
5142 recommended) you can easily generate the patch using the
5143 "git format-patch". If you then use "git send-email" to send it to
5144 the U-Boot mailing list, you will avoid most of the common problems
5145 with some other mail clients.
5147 If you cannot use git, use "diff -purN OLD NEW". If your version of
5148 diff does not support these options, then get the latest version of
5151 The current directory when running this command shall be the parent
5152 directory of the U-Boot source tree (i. e. please make sure that
5153 your patch includes sufficient directory information for the
5156 We prefer patches as plain text. MIME attachments are discouraged,
5157 and compressed attachments must not be used.
5159 * If one logical set of modifications affects or creates several
5160 files, all these changes shall be submitted in a SINGLE patch file.
5162 * Changesets that contain different, unrelated modifications shall be
5163 submitted as SEPARATE patches, one patch per changeset.
5168 * Before sending the patch, run the MAKEALL script on your patched
5169 source tree and make sure that no errors or warnings are reported
5170 for any of the boards.
5172 * Keep your modifications to the necessary minimum: A patch
5173 containing several unrelated changes or arbitrary reformats will be
5174 returned with a request to re-formatting / split it.
5176 * If you modify existing code, make sure that your new code does not
5177 add to the memory footprint of the code ;-) Small is beautiful!
5178 When adding new features, these should compile conditionally only
5179 (using #ifdef), and the resulting code with the new feature
5180 disabled must not need more memory than the old code without your
5183 * Remember that there is a size limit of 100 kB per message on the
5184 u-boot mailing list. Bigger patches will be moderated. If they are
5185 reasonable and not too big, they will be acknowledged. But patches
5186 bigger than the size limit should be avoided.