2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /m68k Files generic to m68k architecture
140 /microblaze Files generic to microblaze architecture
141 /mips Files generic to MIPS architecture
142 /nds32 Files generic to NDS32 architecture
143 /nios2 Files generic to Altera NIOS2 architecture
144 /openrisc Files generic to OpenRISC architecture
145 /powerpc Files generic to PowerPC architecture
146 /sandbox Files generic to HW-independent "sandbox"
147 /sh Files generic to SH architecture
148 /x86 Files generic to x86 architecture
149 /api Machine/arch independent API for external apps
150 /board Board dependent files
151 /cmd U-Boot commands functions
152 /common Misc architecture independent functions
153 /configs Board default configuration files
154 /disk Code for disk drive partition handling
155 /doc Documentation (don't expect too much)
156 /drivers Commonly used device drivers
157 /dts Contains Makefile for building internal U-Boot fdt.
158 /examples Example code for standalone applications, etc.
159 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
160 /include Header Files
161 /lib Library routines generic to all architectures
162 /Licenses Various license files
164 /post Power On Self Test
165 /scripts Various build scripts and Makefiles
166 /test Various unit test files
167 /tools Tools to build S-Record or U-Boot images, etc.
169 Software Configuration:
170 =======================
172 Configuration is usually done using C preprocessor defines; the
173 rationale behind that is to avoid dead code whenever possible.
175 There are two classes of configuration variables:
177 * Configuration _OPTIONS_:
178 These are selectable by the user and have names beginning with
181 * Configuration _SETTINGS_:
182 These depend on the hardware etc. and should not be meddled with if
183 you don't know what you're doing; they have names beginning with
186 Previously, all configuration was done by hand, which involved creating
187 symbolic links and editing configuration files manually. More recently,
188 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
189 allowing you to use the "make menuconfig" command to configure your
193 Selection of Processor Architecture and Board Type:
194 ---------------------------------------------------
196 For all supported boards there are ready-to-use default
197 configurations available; just type "make <board_name>_defconfig".
199 Example: For a TQM823L module type:
202 make TQM823L_defconfig
204 Note: If you're looking for the default configuration file for a board
205 you're sure used to be there but is now missing, check the file
206 doc/README.scrapyard for a list of no longer supported boards.
211 U-Boot can be built natively to run on a Linux host using the 'sandbox'
212 board. This allows feature development which is not board- or architecture-
213 specific to be undertaken on a native platform. The sandbox is also used to
214 run some of U-Boot's tests.
216 See board/sandbox/README.sandbox for more details.
219 Board Initialisation Flow:
220 --------------------------
222 This is the intended start-up flow for boards. This should apply for both
223 SPL and U-Boot proper (i.e. they both follow the same rules).
225 Note: "SPL" stands for "Secondary Program Loader," which is explained in
226 more detail later in this file.
228 At present, SPL mostly uses a separate code path, but the function names
229 and roles of each function are the same. Some boards or architectures
230 may not conform to this. At least most ARM boards which use
231 CONFIG_SPL_FRAMEWORK conform to this.
233 Execution typically starts with an architecture-specific (and possibly
234 CPU-specific) start.S file, such as:
236 - arch/arm/cpu/armv7/start.S
237 - arch/powerpc/cpu/mpc83xx/start.S
238 - arch/mips/cpu/start.S
240 and so on. From there, three functions are called; the purpose and
241 limitations of each of these functions are described below.
244 - purpose: essential init to permit execution to reach board_init_f()
245 - no global_data or BSS
246 - there is no stack (ARMv7 may have one but it will soon be removed)
247 - must not set up SDRAM or use console
248 - must only do the bare minimum to allow execution to continue to
250 - this is almost never needed
251 - return normally from this function
254 - purpose: set up the machine ready for running board_init_r():
255 i.e. SDRAM and serial UART
256 - global_data is available
258 - BSS is not available, so you cannot use global/static variables,
259 only stack variables and global_data
261 Non-SPL-specific notes:
262 - dram_init() is called to set up DRAM. If already done in SPL this
266 - you can override the entire board_init_f() function with your own
268 - preloader_console_init() can be called here in extremis
269 - should set up SDRAM, and anything needed to make the UART work
270 - these is no need to clear BSS, it will be done by crt0.S
271 - must return normally from this function (don't call board_init_r()
274 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
275 this point the stack and global_data are relocated to below
276 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
280 - purpose: main execution, common code
281 - global_data is available
283 - BSS is available, all static/global variables can be used
284 - execution eventually continues to main_loop()
286 Non-SPL-specific notes:
287 - U-Boot is relocated to the top of memory and is now running from
291 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
292 CONFIG_SPL_STACK_R_ADDR points into SDRAM
293 - preloader_console_init() can be called here - typically this is
294 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
295 spl_board_init() function containing this call
296 - loads U-Boot or (in falcon mode) Linux
300 Configuration Options:
301 ----------------------
303 Configuration depends on the combination of board and CPU type; all
304 such information is kept in a configuration file
305 "include/configs/<board_name>.h".
307 Example: For a TQM823L module, all configuration settings are in
308 "include/configs/TQM823L.h".
311 Many of the options are named exactly as the corresponding Linux
312 kernel configuration options. The intention is to make it easier to
313 build a config tool - later.
316 The following options need to be configured:
318 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
320 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
322 - Marvell Family Member
323 CONFIG_SYS_MVFS - define it if you want to enable
324 multiple fs option at one time
325 for marvell soc family
330 Specifies that the core is a 64-bit PowerPC implementation (implements
331 the "64" category of the Power ISA). This is necessary for ePAPR
332 compliance, among other possible reasons.
334 CONFIG_SYS_FSL_TBCLK_DIV
336 Defines the core time base clock divider ratio compared to the
337 system clock. On most PQ3 devices this is 8, on newer QorIQ
338 devices it can be 16 or 32. The ratio varies from SoC to Soc.
340 CONFIG_SYS_FSL_PCIE_COMPAT
342 Defines the string to utilize when trying to match PCIe device
343 tree nodes for the given platform.
345 CONFIG_SYS_FSL_ERRATUM_A004510
347 Enables a workaround for erratum A004510. If set,
348 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
349 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
351 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
352 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
354 Defines one or two SoC revisions (low 8 bits of SVR)
355 for which the A004510 workaround should be applied.
357 The rest of SVR is either not relevant to the decision
358 of whether the erratum is present (e.g. p2040 versus
359 p2041) or is implied by the build target, which controls
360 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
362 See Freescale App Note 4493 for more information about
365 CONFIG_A003399_NOR_WORKAROUND
366 Enables a workaround for IFC erratum A003399. It is only
367 required during NOR boot.
369 CONFIG_A008044_WORKAROUND
370 Enables a workaround for T1040/T1042 erratum A008044. It is only
371 required during NAND boot and valid for Rev 1.0 SoC revision
373 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
375 This is the value to write into CCSR offset 0x18600
376 according to the A004510 workaround.
378 CONFIG_SYS_FSL_DSP_DDR_ADDR
379 This value denotes start offset of DDR memory which is
380 connected exclusively to the DSP cores.
382 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
383 This value denotes start offset of M2 memory
384 which is directly connected to the DSP core.
386 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
387 This value denotes start offset of M3 memory which is directly
388 connected to the DSP core.
390 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
391 This value denotes start offset of DSP CCSR space.
393 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
394 Single Source Clock is clocking mode present in some of FSL SoC's.
395 In this mode, a single differential clock is used to supply
396 clocks to the sysclock, ddrclock and usbclock.
398 CONFIG_SYS_CPC_REINIT_F
399 This CONFIG is defined when the CPC is configured as SRAM at the
400 time of U-Boot entry and is required to be re-initialized.
403 Indicates this SoC supports deep sleep feature. If deep sleep is
404 supported, core will start to execute uboot when wakes up.
406 - Generic CPU options:
407 CONFIG_SYS_GENERIC_GLOBAL_DATA
408 Defines global data is initialized in generic board board_init_f().
409 If this macro is defined, global data is created and cleared in
410 generic board board_init_f(). Without this macro, architecture/board
411 should initialize global data before calling board_init_f().
413 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
415 Defines the endianess of the CPU. Implementation of those
416 values is arch specific.
419 Freescale DDR driver in use. This type of DDR controller is
420 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
423 CONFIG_SYS_FSL_DDR_ADDR
424 Freescale DDR memory-mapped register base.
426 CONFIG_SYS_FSL_DDR_EMU
427 Specify emulator support for DDR. Some DDR features such as
428 deskew training are not available.
430 CONFIG_SYS_FSL_DDRC_GEN1
431 Freescale DDR1 controller.
433 CONFIG_SYS_FSL_DDRC_GEN2
434 Freescale DDR2 controller.
436 CONFIG_SYS_FSL_DDRC_GEN3
437 Freescale DDR3 controller.
439 CONFIG_SYS_FSL_DDRC_GEN4
440 Freescale DDR4 controller.
442 CONFIG_SYS_FSL_DDRC_ARM_GEN3
443 Freescale DDR3 controller for ARM-based SoCs.
446 Board config to use DDR1. It can be enabled for SoCs with
447 Freescale DDR1 or DDR2 controllers, depending on the board
451 Board config to use DDR2. It can be enabled for SoCs with
452 Freescale DDR2 or DDR3 controllers, depending on the board
456 Board config to use DDR3. It can be enabled for SoCs with
457 Freescale DDR3 or DDR3L controllers.
460 Board config to use DDR3L. It can be enabled for SoCs with
464 Board config to use DDR4. It can be enabled for SoCs with
467 CONFIG_SYS_FSL_IFC_BE
468 Defines the IFC controller register space as Big Endian
470 CONFIG_SYS_FSL_IFC_LE
471 Defines the IFC controller register space as Little Endian
473 CONFIG_SYS_FSL_IFC_CLK_DIV
474 Defines divider of platform clock(clock input to IFC controller).
476 CONFIG_SYS_FSL_LBC_CLK_DIV
477 Defines divider of platform clock(clock input to eLBC controller).
479 CONFIG_SYS_FSL_PBL_PBI
480 It enables addition of RCW (Power on reset configuration) in built image.
481 Please refer doc/README.pblimage for more details
483 CONFIG_SYS_FSL_PBL_RCW
484 It adds PBI(pre-boot instructions) commands in u-boot build image.
485 PBI commands can be used to configure SoC before it starts the execution.
486 Please refer doc/README.pblimage for more details
489 It adds a target to create boot binary having SPL binary in PBI format
490 concatenated with u-boot binary.
492 CONFIG_SYS_FSL_DDR_BE
493 Defines the DDR controller register space as Big Endian
495 CONFIG_SYS_FSL_DDR_LE
496 Defines the DDR controller register space as Little Endian
498 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
499 Physical address from the view of DDR controllers. It is the
500 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
501 it could be different for ARM SoCs.
503 CONFIG_SYS_FSL_DDR_INTLV_256B
504 DDR controller interleaving on 256-byte. This is a special
505 interleaving mode, handled by Dickens for Freescale layerscape
508 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
509 Number of controllers used as main memory.
511 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
512 Number of controllers used for other than main memory.
514 CONFIG_SYS_FSL_HAS_DP_DDR
515 Defines the SoC has DP-DDR used for DPAA.
517 CONFIG_SYS_FSL_SEC_BE
518 Defines the SEC controller register space as Big Endian
520 CONFIG_SYS_FSL_SEC_LE
521 Defines the SEC controller register space as Little Endian
524 CONFIG_SYS_INIT_SP_OFFSET
526 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
527 pointer. This is needed for the temporary stack before
530 CONFIG_SYS_MIPS_CACHE_MODE
532 Cache operation mode for the MIPS CPU.
533 See also arch/mips/include/asm/mipsregs.h.
535 CONF_CM_CACHABLE_NO_WA
538 CONF_CM_CACHABLE_NONCOHERENT
542 CONF_CM_CACHABLE_ACCELERATED
544 CONFIG_SYS_XWAY_EBU_BOOTCFG
546 Special option for Lantiq XWAY SoCs for booting from NOR flash.
547 See also arch/mips/cpu/mips32/start.S.
549 CONFIG_XWAY_SWAP_BYTES
551 Enable compilation of tools/xway-swap-bytes needed for Lantiq
552 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
553 be swapped if a flash programmer is used.
556 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
558 Select high exception vectors of the ARM core, e.g., do not
559 clear the V bit of the c1 register of CP15.
562 Generic timer clock source frequency.
564 COUNTER_FREQUENCY_REAL
565 Generic timer clock source frequency if the real clock is
566 different from COUNTER_FREQUENCY, and can only be determined
570 CONFIG_TEGRA_SUPPORT_NON_SECURE
572 Support executing U-Boot in non-secure (NS) mode. Certain
573 impossible actions will be skipped if the CPU is in NS mode,
574 such as ARM architectural timer initialization.
576 - Linux Kernel Interface:
579 U-Boot stores all clock information in Hz
580 internally. For binary compatibility with older Linux
581 kernels (which expect the clocks passed in the
582 bd_info data to be in MHz) the environment variable
583 "clocks_in_mhz" can be defined so that U-Boot
584 converts clock data to MHZ before passing it to the
586 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
587 "clocks_in_mhz=1" is automatically included in the
590 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
592 When transferring memsize parameter to Linux, some versions
593 expect it to be in bytes, others in MB.
594 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
598 New kernel versions are expecting firmware settings to be
599 passed using flattened device trees (based on open firmware
603 * New libfdt-based support
604 * Adds the "fdt" command
605 * The bootm command automatically updates the fdt
607 OF_TBCLK - The timebase frequency.
608 OF_STDOUT_PATH - The path to the console device
610 boards with QUICC Engines require OF_QE to set UCC MAC
613 CONFIG_OF_BOARD_SETUP
615 Board code has addition modification that it wants to make
616 to the flat device tree before handing it off to the kernel
618 CONFIG_OF_SYSTEM_SETUP
620 Other code has addition modification that it wants to make
621 to the flat device tree before handing it off to the kernel.
622 This causes ft_system_setup() to be called before booting
627 U-Boot can detect if an IDE device is present or not.
628 If not, and this new config option is activated, U-Boot
629 removes the ATA node from the DTS before booting Linux,
630 so the Linux IDE driver does not probe the device and
631 crash. This is needed for buggy hardware (uc101) where
632 no pull down resistor is connected to the signal IDE5V_DD7.
634 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
636 This setting is mandatory for all boards that have only one
637 machine type and must be used to specify the machine type
638 number as it appears in the ARM machine registry
639 (see http://www.arm.linux.org.uk/developer/machines/).
640 Only boards that have multiple machine types supported
641 in a single configuration file and the machine type is
642 runtime discoverable, do not have to use this setting.
644 - vxWorks boot parameters:
646 bootvx constructs a valid bootline using the following
647 environments variables: bootdev, bootfile, ipaddr, netmask,
648 serverip, gatewayip, hostname, othbootargs.
649 It loads the vxWorks image pointed bootfile.
651 Note: If a "bootargs" environment is defined, it will overwride
652 the defaults discussed just above.
654 - Cache Configuration:
655 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
656 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
657 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
659 - Cache Configuration for ARM:
660 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
662 CONFIG_SYS_PL310_BASE - Physical base address of PL310
663 controller register space
668 Define this if you want support for Amba PrimeCell PL010 UARTs.
672 Define this if you want support for Amba PrimeCell PL011 UARTs.
676 If you have Amba PrimeCell PL011 UARTs, set this variable to
677 the clock speed of the UARTs.
681 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
682 define this to a list of base addresses for each (supported)
683 port. See e.g. include/configs/versatile.h
685 CONFIG_SERIAL_HW_FLOW_CONTROL
687 Define this variable to enable hw flow control in serial driver.
688 Current user of this option is drivers/serial/nsl16550.c driver
691 CONFIG_BAUDRATE - in bps
692 Select one of the baudrates listed in
693 CONFIG_SYS_BAUDRATE_TABLE, see below.
697 Only needed when CONFIG_BOOTDELAY is enabled;
698 define a command string that is automatically executed
699 when no character is read on the console interface
700 within "Boot Delay" after reset.
703 This can be used to pass arguments to the bootm
704 command. The value of CONFIG_BOOTARGS goes into the
705 environment value "bootargs".
707 CONFIG_RAMBOOT and CONFIG_NFSBOOT
708 The value of these goes into the environment as
709 "ramboot" and "nfsboot" respectively, and can be used
710 as a convenience, when switching between booting from
714 CONFIG_BOOTCOUNT_LIMIT
715 Implements a mechanism for detecting a repeating reboot
717 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
720 If no softreset save registers are found on the hardware
721 "bootcount" is stored in the environment. To prevent a
722 saveenv on all reboots, the environment variable
723 "upgrade_available" is used. If "upgrade_available" is
724 0, "bootcount" is always 0, if "upgrade_available" is
725 1 "bootcount" is incremented in the environment.
726 So the Userspace Applikation must set the "upgrade_available"
727 and "bootcount" variable to 0, if a boot was successfully.
732 When this option is #defined, the existence of the
733 environment variable "preboot" will be checked
734 immediately before starting the CONFIG_BOOTDELAY
735 countdown and/or running the auto-boot command resp.
736 entering interactive mode.
738 This feature is especially useful when "preboot" is
739 automatically generated or modified. For an example
740 see the LWMON board specific code: here "preboot" is
741 modified when the user holds down a certain
742 combination of keys on the (special) keyboard when
745 - Serial Download Echo Mode:
747 If defined to 1, all characters received during a
748 serial download (using the "loads" command) are
749 echoed back. This might be needed by some terminal
750 emulations (like "cu"), but may as well just take
751 time on others. This setting #define's the initial
752 value of the "loads_echo" environment variable.
754 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
756 Select one of the baudrates listed in
757 CONFIG_SYS_BAUDRATE_TABLE, see below.
760 Monitor commands can be included or excluded
761 from the build by using the #include files
762 <config_cmd_all.h> and #undef'ing unwanted
763 commands, or adding #define's for wanted commands.
765 The default command configuration includes all commands
766 except those marked below with a "*".
768 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
769 CONFIG_CMD_ASKENV * ask for env variable
770 CONFIG_CMD_BDI bdinfo
771 CONFIG_CMD_BOOTD bootd
772 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
773 CONFIG_CMD_CACHE * icache, dcache
774 CONFIG_CMD_CONSOLE coninfo
775 CONFIG_CMD_DHCP * DHCP support
776 CONFIG_CMD_DIAG * Diagnostics
777 CONFIG_CMD_ECHO echo arguments
778 CONFIG_CMD_EDITENV edit env variable
779 CONFIG_CMD_ELF * bootelf, bootvx
780 CONFIG_CMD_ENV_EXISTS * check existence of env variable
781 CONFIG_CMD_EXPORTENV * export the environment
782 CONFIG_CMD_EXT2 * ext2 command support
783 CONFIG_CMD_EXT4 * ext4 command support
784 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
785 that work for multiple fs types
786 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
787 CONFIG_CMD_SAVEENV saveenv
788 CONFIG_CMD_FLASH flinfo, erase, protect
789 CONFIG_CMD_FPGA FPGA device initialization support
790 CONFIG_CMD_GO * the 'go' command (exec code)
791 CONFIG_CMD_GREPENV * search environment
792 CONFIG_CMD_I2C * I2C serial bus support
793 CONFIG_CMD_IMI iminfo
794 CONFIG_CMD_IMLS List all images found in NOR flash
795 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
796 CONFIG_CMD_IMPORTENV * import an environment
797 CONFIG_CMD_INI * import data from an ini file into the env
798 CONFIG_CMD_ITEST Integer/string test of 2 values
799 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
800 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
802 CONFIG_CMD_LOADB loadb
803 CONFIG_CMD_LOADS loads
804 CONFIG_CMD_MD5SUM * print md5 message digest
805 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
806 CONFIG_CMD_MEMINFO * Display detailed memory information
807 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
809 CONFIG_CMD_MEMTEST * mtest
810 CONFIG_CMD_MISC Misc functions like sleep etc
811 CONFIG_CMD_MMC * MMC memory mapped support
812 CONFIG_CMD_MII * MII utility commands
813 CONFIG_CMD_NET bootp, tftpboot, rarpboot
814 CONFIG_CMD_NFS NFS support
815 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
817 CONFIG_CMD_RUN run command in env variable
818 CONFIG_CMD_SANDBOX * sb command to access sandbox features
819 CONFIG_CMD_SAVES * save S record dump
820 CONFIG_CMD_SDRAM * print SDRAM configuration information
821 (requires CONFIG_CMD_I2C)
822 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
823 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
824 CONFIG_CMD_SOURCE "source" command Support
825 CONFIG_CMD_SPI * SPI serial bus support
826 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
827 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
828 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
829 CONFIG_CMD_TIMER * access to the system tick timer
830 CONFIG_CMD_USB * USB support
831 CONFIG_CMD_CDP * Cisco Discover Protocol support
832 CONFIG_CMD_XIMG Load part of Multi Image
833 CONFIG_CMD_UUID * Generate random UUID or GUID string
835 EXAMPLE: If you want all functions except of network
836 support you can write:
838 #include "config_cmd_all.h"
839 #undef CONFIG_CMD_NET
842 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
844 Note: Don't enable the "icache" and "dcache" commands
845 (configuration option CONFIG_CMD_CACHE) unless you know
846 what you (and your U-Boot users) are doing. Data
847 cache cannot be enabled on systems like the
848 8xx (where accesses to the IMMR region must be
849 uncached), and it cannot be disabled on all other
850 systems where we (mis-) use the data cache to hold an
851 initial stack and some data.
854 XXX - this list needs to get updated!
856 - Removal of commands
857 If no commands are needed to boot, you can disable
858 CONFIG_CMDLINE to remove them. In this case, the command line
859 will not be available, and when U-Boot wants to execute the
860 boot command (on start-up) it will call board_run_command()
861 instead. This can reduce image size significantly for very
862 simple boot procedures.
864 - Regular expression support:
866 If this variable is defined, U-Boot is linked against
867 the SLRE (Super Light Regular Expression) library,
868 which adds regex support to some commands, as for
869 example "env grep" and "setexpr".
873 If this variable is defined, U-Boot will use a device tree
874 to configure its devices, instead of relying on statically
875 compiled #defines in the board file. This option is
876 experimental and only available on a few boards. The device
877 tree is available in the global data as gd->fdt_blob.
879 U-Boot needs to get its device tree from somewhere. This can
880 be done using one of the three options below:
883 If this variable is defined, U-Boot will embed a device tree
884 binary in its image. This device tree file should be in the
885 board directory and called <soc>-<board>.dts. The binary file
886 is then picked up in board_init_f() and made available through
887 the global data structure as gd->blob.
890 If this variable is defined, U-Boot will build a device tree
891 binary. It will be called u-boot.dtb. Architecture-specific
892 code will locate it at run-time. Generally this works by:
894 cat u-boot.bin u-boot.dtb >image.bin
896 and in fact, U-Boot does this for you, creating a file called
897 u-boot-dtb.bin which is useful in the common case. You can
898 still use the individual files if you need something more
902 If this variable is defined, U-Boot will use the device tree
903 provided by the board at runtime instead of embedding one with
904 the image. Only boards defining board_fdt_blob_setup() support
905 this option (see include/fdtdec.h file).
909 If this variable is defined, it enables watchdog
910 support for the SoC. There must be support in the SoC
911 specific code for a watchdog. For the 8xx
912 CPUs, the SIU Watchdog feature is enabled in the SYPCR
913 register. When supported for a specific SoC is
914 available, then no further board specific code should
918 When using a watchdog circuitry external to the used
919 SoC, then define this variable and provide board
920 specific code for the "hw_watchdog_reset" function.
922 CONFIG_AT91_HW_WDT_TIMEOUT
923 specify the timeout in seconds. default 2 seconds.
926 CONFIG_VERSION_VARIABLE
927 If this variable is defined, an environment variable
928 named "ver" is created by U-Boot showing the U-Boot
929 version as printed by the "version" command.
930 Any change to this variable will be reverted at the
935 When CONFIG_CMD_DATE is selected, the type of the RTC
936 has to be selected, too. Define exactly one of the
939 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
940 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
941 CONFIG_RTC_MC146818 - use MC146818 RTC
942 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
943 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
944 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
945 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
946 CONFIG_RTC_DS164x - use Dallas DS164x RTC
947 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
948 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
949 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
950 CONFIG_SYS_RV3029_TCR - enable trickle charger on
953 Note that if the RTC uses I2C, then the I2C interface
954 must also be configured. See I2C Support, below.
957 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
959 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
960 chip-ngpio pairs that tell the PCA953X driver the number of
961 pins supported by a particular chip.
963 Note that if the GPIO device uses I2C, then the I2C interface
964 must also be configured. See I2C Support, below.
967 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
968 accesses and can checksum them or write a list of them out
969 to memory. See the 'iotrace' command for details. This is
970 useful for testing device drivers since it can confirm that
971 the driver behaves the same way before and after a code
972 change. Currently this is supported on sandbox and arm. To
973 add support for your architecture, add '#include <iotrace.h>'
974 to the bottom of arch/<arch>/include/asm/io.h and test.
976 Example output from the 'iotrace stats' command is below.
977 Note that if the trace buffer is exhausted, the checksum will
978 still continue to operate.
981 Start: 10000000 (buffer start address)
982 Size: 00010000 (buffer size)
983 Offset: 00000120 (current buffer offset)
984 Output: 10000120 (start + offset)
985 Count: 00000018 (number of trace records)
986 CRC32: 9526fb66 (CRC32 of all trace records)
990 When CONFIG_TIMESTAMP is selected, the timestamp
991 (date and time) of an image is printed by image
992 commands like bootm or iminfo. This option is
993 automatically enabled when you select CONFIG_CMD_DATE .
995 - Partition Labels (disklabels) Supported:
996 Zero or more of the following:
997 CONFIG_MAC_PARTITION Apple's MacOS partition table.
998 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
999 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1000 bootloader. Note 2TB partition limit; see
1002 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1004 If IDE or SCSI support is enabled (CONFIG_IDE or
1005 CONFIG_SCSI) you must configure support for at
1006 least one non-MTD partition type as well.
1009 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1010 board configurations files but used nowhere!
1012 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1013 be performed by calling the function
1014 ide_set_reset(int reset)
1015 which has to be defined in a board specific file
1020 Set this to enable ATAPI support.
1025 Set this to enable support for disks larger than 137GB
1026 Also look at CONFIG_SYS_64BIT_LBA.
1027 Whithout these , LBA48 support uses 32bit variables and will 'only'
1028 support disks up to 2.1TB.
1030 CONFIG_SYS_64BIT_LBA:
1031 When enabled, makes the IDE subsystem use 64bit sector addresses.
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
1041 The environment variable 'scsidevs' is set to the number of
1042 SCSI devices found during the last scan.
1044 - NETWORK Support (PCI):
1046 Support for Intel 8254x/8257x gigabit chips.
1049 Utility code for direct access to the SPI bus on Intel 8257x.
1050 This does not do anything useful unless you set at least one
1051 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1053 CONFIG_E1000_SPI_GENERIC
1054 Allow generic access to the SPI bus on the Intel 8257x, for
1055 example with the "sspi" command.
1058 Management command for E1000 devices. When used on devices
1059 with SPI support you can reprogram the EEPROM from U-Boot.
1062 Support for Intel 82557/82559/82559ER chips.
1063 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1064 write routine for first time initialisation.
1067 Support for Digital 2114x chips.
1068 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1069 modem chip initialisation (KS8761/QS6611).
1072 Support for National dp83815 chips.
1075 Support for National dp8382[01] gigabit chips.
1077 - NETWORK Support (other):
1079 CONFIG_DRIVER_AT91EMAC
1080 Support for AT91RM9200 EMAC.
1083 Define this to use reduced MII inteface
1085 CONFIG_DRIVER_AT91EMAC_QUIET
1086 If this defined, the driver is quiet.
1087 The driver doen't show link status messages.
1089 CONFIG_CALXEDA_XGMAC
1090 Support for the Calxeda XGMAC device
1093 Support for SMSC's LAN91C96 chips.
1095 CONFIG_LAN91C96_USE_32_BIT
1096 Define this to enable 32 bit addressing
1099 Support for SMSC's LAN91C111 chip
1101 CONFIG_SMC91111_BASE
1102 Define this to hold the physical address
1103 of the device (I/O space)
1105 CONFIG_SMC_USE_32_BIT
1106 Define this if data bus is 32 bits
1108 CONFIG_SMC_USE_IOFUNCS
1109 Define this to use i/o functions instead of macros
1110 (some hardware wont work with macros)
1112 CONFIG_DRIVER_TI_EMAC
1113 Support for davinci emac
1115 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1116 Define this if you have more then 3 PHYs.
1119 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1121 CONFIG_FTGMAC100_EGIGA
1122 Define this to use GE link update with gigabit PHY.
1123 Define this if FTGMAC100 is connected to gigabit PHY.
1124 If your system has 10/100 PHY only, it might not occur
1125 wrong behavior. Because PHY usually return timeout or
1126 useless data when polling gigabit status and gigabit
1127 control registers. This behavior won't affect the
1128 correctnessof 10/100 link speed update.
1131 Support for SMSC's LAN911x and LAN921x chips
1134 Define this to hold the physical address
1135 of the device (I/O space)
1137 CONFIG_SMC911X_32_BIT
1138 Define this if data bus is 32 bits
1140 CONFIG_SMC911X_16_BIT
1141 Define this if data bus is 16 bits. If your processor
1142 automatically converts one 32 bit word to two 16 bit
1143 words you may also try CONFIG_SMC911X_32_BIT.
1146 Support for Renesas on-chip Ethernet controller
1148 CONFIG_SH_ETHER_USE_PORT
1149 Define the number of ports to be used
1151 CONFIG_SH_ETHER_PHY_ADDR
1152 Define the ETH PHY's address
1154 CONFIG_SH_ETHER_CACHE_WRITEBACK
1155 If this option is set, the driver enables cache flush.
1159 Support for PWM module on the imx6.
1163 Support TPM devices.
1165 CONFIG_TPM_TIS_INFINEON
1166 Support for Infineon i2c bus TPM devices. Only one device
1167 per system is supported at this time.
1169 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1170 Define the burst count bytes upper limit
1173 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1175 CONFIG_TPM_ST33ZP24_I2C
1176 Support for STMicroelectronics ST33ZP24 I2C devices.
1177 Requires TPM_ST33ZP24 and I2C.
1179 CONFIG_TPM_ST33ZP24_SPI
1180 Support for STMicroelectronics ST33ZP24 SPI devices.
1181 Requires TPM_ST33ZP24 and SPI.
1183 CONFIG_TPM_ATMEL_TWI
1184 Support for Atmel TWI TPM device. Requires I2C support.
1187 Support for generic parallel port TPM devices. Only one device
1188 per system is supported at this time.
1190 CONFIG_TPM_TIS_BASE_ADDRESS
1191 Base address where the generic TPM device is mapped
1192 to. Contemporary x86 systems usually map it at
1196 Add tpm monitor functions.
1197 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1198 provides monitor access to authorized functions.
1201 Define this to enable the TPM support library which provides
1202 functional interfaces to some TPM commands.
1203 Requires support for a TPM device.
1205 CONFIG_TPM_AUTH_SESSIONS
1206 Define this to enable authorized functions in the TPM library.
1207 Requires CONFIG_TPM and CONFIG_SHA1.
1210 At the moment only the UHCI host controller is
1211 supported (PIP405, MIP405); define
1212 CONFIG_USB_UHCI to enable it.
1213 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1214 and define CONFIG_USB_STORAGE to enable the USB
1217 Supported are USB Keyboards and USB Floppy drives
1220 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1221 txfilltuning field in the EHCI controller on reset.
1223 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1224 HW module registers.
1227 Define the below if you wish to use the USB console.
1228 Once firmware is rebuilt from a serial console issue the
1229 command "setenv stdin usbtty; setenv stdout usbtty" and
1230 attach your USB cable. The Unix command "dmesg" should print
1231 it has found a new device. The environment variable usbtty
1232 can be set to gserial or cdc_acm to enable your device to
1233 appear to a USB host as a Linux gserial device or a
1234 Common Device Class Abstract Control Model serial device.
1235 If you select usbtty = gserial you should be able to enumerate
1237 # modprobe usbserial vendor=0xVendorID product=0xProductID
1238 else if using cdc_acm, simply setting the environment
1239 variable usbtty to be cdc_acm should suffice. The following
1240 might be defined in YourBoardName.h
1243 Define this to build a UDC device
1246 Define this to have a tty type of device available to
1247 talk to the UDC device
1250 Define this to enable the high speed support for usb
1251 device and usbtty. If this feature is enabled, a routine
1252 int is_usbd_high_speed(void)
1253 also needs to be defined by the driver to dynamically poll
1254 whether the enumeration has succeded at high speed or full
1257 CONFIG_SYS_CONSOLE_IS_IN_ENV
1258 Define this if you want stdin, stdout &/or stderr to
1261 If you have a USB-IF assigned VendorID then you may wish to
1262 define your own vendor specific values either in BoardName.h
1263 or directly in usbd_vendor_info.h. If you don't define
1264 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1265 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1266 should pretend to be a Linux device to it's target host.
1268 CONFIG_USBD_MANUFACTURER
1269 Define this string as the name of your company for
1270 - CONFIG_USBD_MANUFACTURER "my company"
1272 CONFIG_USBD_PRODUCT_NAME
1273 Define this string as the name of your product
1274 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1276 CONFIG_USBD_VENDORID
1277 Define this as your assigned Vendor ID from the USB
1278 Implementors Forum. This *must* be a genuine Vendor ID
1279 to avoid polluting the USB namespace.
1280 - CONFIG_USBD_VENDORID 0xFFFF
1282 CONFIG_USBD_PRODUCTID
1283 Define this as the unique Product ID
1285 - CONFIG_USBD_PRODUCTID 0xFFFF
1287 - ULPI Layer Support:
1288 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1289 the generic ULPI layer. The generic layer accesses the ULPI PHY
1290 via the platform viewport, so you need both the genric layer and
1291 the viewport enabled. Currently only Chipidea/ARC based
1292 viewport is supported.
1293 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1294 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1295 If your ULPI phy needs a different reference clock than the
1296 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1297 the appropriate value in Hz.
1300 The MMC controller on the Intel PXA is supported. To
1301 enable this define CONFIG_MMC. The MMC can be
1302 accessed from the boot prompt by mapping the device
1303 to physical memory similar to flash. Command line is
1304 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1305 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1308 Support for Renesas on-chip MMCIF controller
1310 CONFIG_SH_MMCIF_ADDR
1311 Define the base address of MMCIF registers
1314 Define the clock frequency for MMCIF
1316 CONFIG_SUPPORT_EMMC_BOOT
1317 Enable some additional features of the eMMC boot partitions.
1319 CONFIG_SUPPORT_EMMC_RPMB
1320 Enable the commands for reading, writing and programming the
1321 key for the Replay Protection Memory Block partition in eMMC.
1323 - USB Device Firmware Update (DFU) class support:
1324 CONFIG_USB_FUNCTION_DFU
1325 This enables the USB portion of the DFU USB class
1328 This enables the command "dfu" which is used to have
1329 U-Boot create a DFU class device via USB. This command
1330 requires that the "dfu_alt_info" environment variable be
1331 set and define the alt settings to expose to the host.
1334 This enables support for exposing (e)MMC devices via DFU.
1337 This enables support for exposing NAND devices via DFU.
1340 This enables support for exposing RAM via DFU.
1341 Note: DFU spec refer to non-volatile memory usage, but
1342 allow usages beyond the scope of spec - here RAM usage,
1343 one that would help mostly the developer.
1345 CONFIG_SYS_DFU_DATA_BUF_SIZE
1346 Dfu transfer uses a buffer before writing data to the
1347 raw storage device. Make the size (in bytes) of this buffer
1348 configurable. The size of this buffer is also configurable
1349 through the "dfu_bufsiz" environment variable.
1351 CONFIG_SYS_DFU_MAX_FILE_SIZE
1352 When updating files rather than the raw storage device,
1353 we use a static buffer to copy the file into and then write
1354 the buffer once we've been given the whole file. Define
1355 this to the maximum filesize (in bytes) for the buffer.
1356 Default is 4 MiB if undefined.
1358 DFU_DEFAULT_POLL_TIMEOUT
1359 Poll timeout [ms], is the timeout a device can send to the
1360 host. The host must wait for this timeout before sending
1361 a subsequent DFU_GET_STATUS request to the device.
1363 DFU_MANIFEST_POLL_TIMEOUT
1364 Poll timeout [ms], which the device sends to the host when
1365 entering dfuMANIFEST state. Host waits this timeout, before
1366 sending again an USB request to the device.
1368 - USB Device Android Fastboot support:
1369 CONFIG_USB_FUNCTION_FASTBOOT
1370 This enables the USB part of the fastboot gadget
1373 This enables the command "fastboot" which enables the Android
1374 fastboot mode for the platform's USB device. Fastboot is a USB
1375 protocol for downloading images, flashing and device control
1376 used on Android devices.
1377 See doc/README.android-fastboot for more information.
1379 CONFIG_ANDROID_BOOT_IMAGE
1380 This enables support for booting images which use the Android
1381 image format header.
1383 CONFIG_FASTBOOT_BUF_ADDR
1384 The fastboot protocol requires a large memory buffer for
1385 downloads. Define this to the starting RAM address to use for
1388 CONFIG_FASTBOOT_BUF_SIZE
1389 The fastboot protocol requires a large memory buffer for
1390 downloads. This buffer should be as large as possible for a
1391 platform. Define this to the size available RAM for fastboot.
1393 CONFIG_FASTBOOT_FLASH
1394 The fastboot protocol includes a "flash" command for writing
1395 the downloaded image to a non-volatile storage device. Define
1396 this to enable the "fastboot flash" command.
1398 CONFIG_FASTBOOT_FLASH_MMC_DEV
1399 The fastboot "flash" command requires additional information
1400 regarding the non-volatile storage device. Define this to
1401 the eMMC device that fastboot should use to store the image.
1403 CONFIG_FASTBOOT_GPT_NAME
1404 The fastboot "flash" command supports writing the downloaded
1405 image to the Protective MBR and the Primary GUID Partition
1406 Table. (Additionally, this downloaded image is post-processed
1407 to generate and write the Backup GUID Partition Table.)
1408 This occurs when the specified "partition name" on the
1409 "fastboot flash" command line matches this value.
1410 The default is "gpt" if undefined.
1412 CONFIG_FASTBOOT_MBR_NAME
1413 The fastboot "flash" command supports writing the downloaded
1415 This occurs when the "partition name" specified on the
1416 "fastboot flash" command line matches this value.
1417 If not defined the default value "mbr" is used.
1419 - Journaling Flash filesystem support:
1421 Define these for a default partition on a NAND device
1423 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1424 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1425 Define these for a default partition on a NOR device
1428 See Kconfig help for available keyboard drivers.
1432 Define this to enable a custom keyboard support.
1433 This simply calls drv_keyboard_init() which must be
1434 defined in your board-specific files. This option is deprecated
1435 and is only used by novena. For new boards, use driver model
1440 Enable the Freescale DIU video driver. Reference boards for
1441 SOCs that have a DIU should define this macro to enable DIU
1442 support, and should also define these other macros:
1447 CONFIG_VIDEO_SW_CURSOR
1448 CONFIG_VGA_AS_SINGLE_DEVICE
1450 CONFIG_VIDEO_BMP_LOGO
1452 The DIU driver will look for the 'video-mode' environment
1453 variable, and if defined, enable the DIU as a console during
1454 boot. See the documentation file doc/README.video for a
1455 description of this variable.
1457 - LCD Support: CONFIG_LCD
1459 Define this to enable LCD support (for output to LCD
1460 display); also select one of the supported displays
1461 by defining one of these:
1465 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1467 CONFIG_NEC_NL6448AC33:
1469 NEC NL6448AC33-18. Active, color, single scan.
1471 CONFIG_NEC_NL6448BC20
1473 NEC NL6448BC20-08. 6.5", 640x480.
1474 Active, color, single scan.
1476 CONFIG_NEC_NL6448BC33_54
1478 NEC NL6448BC33-54. 10.4", 640x480.
1479 Active, color, single scan.
1483 Sharp 320x240. Active, color, single scan.
1484 It isn't 16x9, and I am not sure what it is.
1486 CONFIG_SHARP_LQ64D341
1488 Sharp LQ64D341 display, 640x480.
1489 Active, color, single scan.
1493 HLD1045 display, 640x480.
1494 Active, color, single scan.
1498 Optrex CBL50840-2 NF-FW 99 22 M5
1500 Hitachi LMG6912RPFC-00T
1504 320x240. Black & white.
1506 CONFIG_LCD_ALIGNMENT
1508 Normally the LCD is page-aligned (typically 4KB). If this is
1509 defined then the LCD will be aligned to this value instead.
1510 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1511 here, since it is cheaper to change data cache settings on
1512 a per-section basis.
1517 Sometimes, for example if the display is mounted in portrait
1518 mode or even if it's mounted landscape but rotated by 180degree,
1519 we need to rotate our content of the display relative to the
1520 framebuffer, so that user can read the messages which are
1522 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1523 initialized with a given rotation from "vl_rot" out of
1524 "vidinfo_t" which is provided by the board specific code.
1525 The value for vl_rot is coded as following (matching to
1526 fbcon=rotate:<n> linux-kernel commandline):
1527 0 = no rotation respectively 0 degree
1528 1 = 90 degree rotation
1529 2 = 180 degree rotation
1530 3 = 270 degree rotation
1532 If CONFIG_LCD_ROTATION is not defined, the console will be
1533 initialized with 0degree rotation.
1537 Support drawing of RLE8-compressed bitmaps on the LCD.
1541 Enables an 'i2c edid' command which can read EDID
1542 information over I2C from an attached LCD display.
1544 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1546 If this option is set, the environment is checked for
1547 a variable "splashimage". If found, the usual display
1548 of logo, copyright and system information on the LCD
1549 is suppressed and the BMP image at the address
1550 specified in "splashimage" is loaded instead. The
1551 console is redirected to the "nulldev", too. This
1552 allows for a "silent" boot where a splash screen is
1553 loaded very quickly after power-on.
1555 CONFIG_SPLASHIMAGE_GUARD
1557 If this option is set, then U-Boot will prevent the environment
1558 variable "splashimage" from being set to a problematic address
1559 (see doc/README.displaying-bmps).
1560 This option is useful for targets where, due to alignment
1561 restrictions, an improperly aligned BMP image will cause a data
1562 abort. If you think you will not have problems with unaligned
1563 accesses (for example because your toolchain prevents them)
1564 there is no need to set this option.
1566 CONFIG_SPLASH_SCREEN_ALIGN
1568 If this option is set the splash image can be freely positioned
1569 on the screen. Environment variable "splashpos" specifies the
1570 position as "x,y". If a positive number is given it is used as
1571 number of pixel from left/top. If a negative number is given it
1572 is used as number of pixel from right/bottom. You can also
1573 specify 'm' for centering the image.
1576 setenv splashpos m,m
1577 => image at center of screen
1579 setenv splashpos 30,20
1580 => image at x = 30 and y = 20
1582 setenv splashpos -10,m
1583 => vertically centered image
1584 at x = dspWidth - bmpWidth - 9
1586 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1588 If this option is set, additionally to standard BMP
1589 images, gzipped BMP images can be displayed via the
1590 splashscreen support or the bmp command.
1592 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1594 If this option is set, 8-bit RLE compressed BMP images
1595 can be displayed via the splashscreen support or the
1598 - Compression support:
1601 Enabled by default to support gzip compressed images.
1605 If this option is set, support for bzip2 compressed
1606 images is included. If not, only uncompressed and gzip
1607 compressed images are supported.
1609 NOTE: the bzip2 algorithm requires a lot of RAM, so
1610 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1616 The address of PHY on MII bus.
1618 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1620 The clock frequency of the MII bus
1622 CONFIG_PHY_RESET_DELAY
1624 Some PHY like Intel LXT971A need extra delay after
1625 reset before any MII register access is possible.
1626 For such PHY, set this option to the usec delay
1627 required. (minimum 300usec for LXT971A)
1629 CONFIG_PHY_CMD_DELAY (ppc4xx)
1631 Some PHY like Intel LXT971A need extra delay after
1632 command issued before MII status register can be read
1637 Define a default value for the IP address to use for
1638 the default Ethernet interface, in case this is not
1639 determined through e.g. bootp.
1640 (Environment variable "ipaddr")
1642 - Server IP address:
1645 Defines a default value for the IP address of a TFTP
1646 server to contact when using the "tftboot" command.
1647 (Environment variable "serverip")
1649 CONFIG_KEEP_SERVERADDR
1651 Keeps the server's MAC address, in the env 'serveraddr'
1652 for passing to bootargs (like Linux's netconsole option)
1654 - Gateway IP address:
1657 Defines a default value for the IP address of the
1658 default router where packets to other networks are
1660 (Environment variable "gatewayip")
1665 Defines a default value for the subnet mask (or
1666 routing prefix) which is used to determine if an IP
1667 address belongs to the local subnet or needs to be
1668 forwarded through a router.
1669 (Environment variable "netmask")
1671 - Multicast TFTP Mode:
1674 Defines whether you want to support multicast TFTP as per
1675 rfc-2090; for example to work with atftp. Lets lots of targets
1676 tftp down the same boot image concurrently. Note: the Ethernet
1677 driver in use must provide a function: mcast() to join/leave a
1680 - BOOTP Recovery Mode:
1681 CONFIG_BOOTP_RANDOM_DELAY
1683 If you have many targets in a network that try to
1684 boot using BOOTP, you may want to avoid that all
1685 systems send out BOOTP requests at precisely the same
1686 moment (which would happen for instance at recovery
1687 from a power failure, when all systems will try to
1688 boot, thus flooding the BOOTP server. Defining
1689 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1690 inserted before sending out BOOTP requests. The
1691 following delays are inserted then:
1693 1st BOOTP request: delay 0 ... 1 sec
1694 2nd BOOTP request: delay 0 ... 2 sec
1695 3rd BOOTP request: delay 0 ... 4 sec
1697 BOOTP requests: delay 0 ... 8 sec
1699 CONFIG_BOOTP_ID_CACHE_SIZE
1701 BOOTP packets are uniquely identified using a 32-bit ID. The
1702 server will copy the ID from client requests to responses and
1703 U-Boot will use this to determine if it is the destination of
1704 an incoming response. Some servers will check that addresses
1705 aren't in use before handing them out (usually using an ARP
1706 ping) and therefore take up to a few hundred milliseconds to
1707 respond. Network congestion may also influence the time it
1708 takes for a response to make it back to the client. If that
1709 time is too long, U-Boot will retransmit requests. In order
1710 to allow earlier responses to still be accepted after these
1711 retransmissions, U-Boot's BOOTP client keeps a small cache of
1712 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1713 cache. The default is to keep IDs for up to four outstanding
1714 requests. Increasing this will allow U-Boot to accept offers
1715 from a BOOTP client in networks with unusually high latency.
1717 - DHCP Advanced Options:
1718 You can fine tune the DHCP functionality by defining
1719 CONFIG_BOOTP_* symbols:
1721 CONFIG_BOOTP_SUBNETMASK
1722 CONFIG_BOOTP_GATEWAY
1723 CONFIG_BOOTP_HOSTNAME
1724 CONFIG_BOOTP_NISDOMAIN
1725 CONFIG_BOOTP_BOOTPATH
1726 CONFIG_BOOTP_BOOTFILESIZE
1729 CONFIG_BOOTP_SEND_HOSTNAME
1730 CONFIG_BOOTP_NTPSERVER
1731 CONFIG_BOOTP_TIMEOFFSET
1732 CONFIG_BOOTP_VENDOREX
1733 CONFIG_BOOTP_MAY_FAIL
1735 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1736 environment variable, not the BOOTP server.
1738 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1739 after the configured retry count, the call will fail
1740 instead of starting over. This can be used to fail over
1741 to Link-local IP address configuration if the DHCP server
1744 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1745 serverip from a DHCP server, it is possible that more
1746 than one DNS serverip is offered to the client.
1747 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1748 serverip will be stored in the additional environment
1749 variable "dnsip2". The first DNS serverip is always
1750 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1753 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1754 to do a dynamic update of a DNS server. To do this, they
1755 need the hostname of the DHCP requester.
1756 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1757 of the "hostname" environment variable is passed as
1758 option 12 to the DHCP server.
1760 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1762 A 32bit value in microseconds for a delay between
1763 receiving a "DHCP Offer" and sending the "DHCP Request".
1764 This fixes a problem with certain DHCP servers that don't
1765 respond 100% of the time to a "DHCP request". E.g. On an
1766 AT91RM9200 processor running at 180MHz, this delay needed
1767 to be *at least* 15,000 usec before a Windows Server 2003
1768 DHCP server would reply 100% of the time. I recommend at
1769 least 50,000 usec to be safe. The alternative is to hope
1770 that one of the retries will be successful but note that
1771 the DHCP timeout and retry process takes a longer than
1774 - Link-local IP address negotiation:
1775 Negotiate with other link-local clients on the local network
1776 for an address that doesn't require explicit configuration.
1777 This is especially useful if a DHCP server cannot be guaranteed
1778 to exist in all environments that the device must operate.
1780 See doc/README.link-local for more information.
1783 CONFIG_CDP_DEVICE_ID
1785 The device id used in CDP trigger frames.
1787 CONFIG_CDP_DEVICE_ID_PREFIX
1789 A two character string which is prefixed to the MAC address
1794 A printf format string which contains the ascii name of
1795 the port. Normally is set to "eth%d" which sets
1796 eth0 for the first Ethernet, eth1 for the second etc.
1798 CONFIG_CDP_CAPABILITIES
1800 A 32bit integer which indicates the device capabilities;
1801 0x00000010 for a normal host which does not forwards.
1805 An ascii string containing the version of the software.
1809 An ascii string containing the name of the platform.
1813 A 32bit integer sent on the trigger.
1815 CONFIG_CDP_POWER_CONSUMPTION
1817 A 16bit integer containing the power consumption of the
1818 device in .1 of milliwatts.
1820 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1822 A byte containing the id of the VLAN.
1824 - Status LED: CONFIG_LED_STATUS
1826 Several configurations allow to display the current
1827 status using a LED. For instance, the LED will blink
1828 fast while running U-Boot code, stop blinking as
1829 soon as a reply to a BOOTP request was received, and
1830 start blinking slow once the Linux kernel is running
1831 (supported by a status LED driver in the Linux
1832 kernel). Defining CONFIG_LED_STATUS enables this
1837 CONFIG_LED_STATUS_GPIO
1838 The status LED can be connected to a GPIO pin.
1839 In such cases, the gpio_led driver can be used as a
1840 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1841 to include the gpio_led driver in the U-Boot binary.
1843 CONFIG_GPIO_LED_INVERTED_TABLE
1844 Some GPIO connected LEDs may have inverted polarity in which
1845 case the GPIO high value corresponds to LED off state and
1846 GPIO low value corresponds to LED on state.
1847 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1848 with a list of GPIO LEDs that have inverted polarity.
1850 - I2C Support: CONFIG_SYS_I2C
1852 This enable the NEW i2c subsystem, and will allow you to use
1853 i2c commands at the u-boot command line (as long as you set
1854 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1855 based realtime clock chips or other i2c devices. See
1856 common/cmd_i2c.c for a description of the command line
1859 ported i2c driver to the new framework:
1860 - drivers/i2c/soft_i2c.c:
1861 - activate first bus with CONFIG_SYS_I2C_SOFT define
1862 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1863 for defining speed and slave address
1864 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1865 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1866 for defining speed and slave address
1867 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1868 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1869 for defining speed and slave address
1870 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1871 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1872 for defining speed and slave address
1874 - drivers/i2c/fsl_i2c.c:
1875 - activate i2c driver with CONFIG_SYS_I2C_FSL
1876 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1877 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1878 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1880 - If your board supports a second fsl i2c bus, define
1881 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1882 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1883 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1886 - drivers/i2c/tegra_i2c.c:
1887 - activate this driver with CONFIG_SYS_I2C_TEGRA
1888 - This driver adds 4 i2c buses with a fix speed from
1889 100000 and the slave addr 0!
1891 - drivers/i2c/ppc4xx_i2c.c
1892 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1893 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1894 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1896 - drivers/i2c/i2c_mxc.c
1897 - activate this driver with CONFIG_SYS_I2C_MXC
1898 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1899 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1900 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1901 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1902 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1903 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1904 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1905 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1906 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1907 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1908 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1909 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1910 If those defines are not set, default value is 100000
1911 for speed, and 0 for slave.
1913 - drivers/i2c/rcar_i2c.c:
1914 - activate this driver with CONFIG_SYS_I2C_RCAR
1915 - This driver adds 4 i2c buses
1917 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1918 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1919 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1920 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1921 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1922 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1923 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1924 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1925 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1927 - drivers/i2c/sh_i2c.c:
1928 - activate this driver with CONFIG_SYS_I2C_SH
1929 - This driver adds from 2 to 5 i2c buses
1931 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1932 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1933 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1934 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1935 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1936 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1937 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1938 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1939 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1940 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1941 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1943 - drivers/i2c/omap24xx_i2c.c
1944 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1945 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1946 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1947 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1948 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1949 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1950 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1951 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1952 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1953 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1954 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1956 - drivers/i2c/zynq_i2c.c
1957 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1958 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1959 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1961 - drivers/i2c/s3c24x0_i2c.c:
1962 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1963 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1964 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1965 with a fix speed from 100000 and the slave addr 0!
1967 - drivers/i2c/ihs_i2c.c
1968 - activate this driver with CONFIG_SYS_I2C_IHS
1969 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1970 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1971 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1972 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1973 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1974 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1975 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1976 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1977 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1978 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1979 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1980 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1981 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1982 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1983 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1984 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1985 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1986 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1987 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1988 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1989 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1993 CONFIG_SYS_NUM_I2C_BUSES
1994 Hold the number of i2c buses you want to use.
1996 CONFIG_SYS_I2C_DIRECT_BUS
1997 define this, if you don't use i2c muxes on your hardware.
1998 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2001 CONFIG_SYS_I2C_MAX_HOPS
2002 define how many muxes are maximal consecutively connected
2003 on one i2c bus. If you not use i2c muxes, omit this
2006 CONFIG_SYS_I2C_BUSES
2007 hold a list of buses you want to use, only used if
2008 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2009 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2010 CONFIG_SYS_NUM_I2C_BUSES = 9:
2012 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2013 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2014 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2015 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2016 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2017 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2018 {1, {I2C_NULL_HOP}}, \
2019 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2020 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2024 bus 0 on adapter 0 without a mux
2025 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2026 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2027 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2028 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2029 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2030 bus 6 on adapter 1 without a mux
2031 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2032 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2034 If you do not have i2c muxes on your board, omit this define.
2036 - Legacy I2C Support:
2037 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2038 then the following macros need to be defined (examples are
2039 from include/configs/lwmon.h):
2043 (Optional). Any commands necessary to enable the I2C
2044 controller or configure ports.
2046 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2050 The code necessary to make the I2C data line active
2051 (driven). If the data line is open collector, this
2054 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2058 The code necessary to make the I2C data line tri-stated
2059 (inactive). If the data line is open collector, this
2062 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2066 Code that returns true if the I2C data line is high,
2069 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2073 If <bit> is true, sets the I2C data line high. If it
2074 is false, it clears it (low).
2076 eg: #define I2C_SDA(bit) \
2077 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2078 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2082 If <bit> is true, sets the I2C clock line high. If it
2083 is false, it clears it (low).
2085 eg: #define I2C_SCL(bit) \
2086 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2087 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2091 This delay is invoked four times per clock cycle so this
2092 controls the rate of data transfer. The data rate thus
2093 is 1 / (I2C_DELAY * 4). Often defined to be something
2096 #define I2C_DELAY udelay(2)
2098 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2100 If your arch supports the generic GPIO framework (asm/gpio.h),
2101 then you may alternatively define the two GPIOs that are to be
2102 used as SCL / SDA. Any of the previous I2C_xxx macros will
2103 have GPIO-based defaults assigned to them as appropriate.
2105 You should define these to the GPIO value as given directly to
2106 the generic GPIO functions.
2108 CONFIG_SYS_I2C_INIT_BOARD
2110 When a board is reset during an i2c bus transfer
2111 chips might think that the current transfer is still
2112 in progress. On some boards it is possible to access
2113 the i2c SCLK line directly, either by using the
2114 processor pin as a GPIO or by having a second pin
2115 connected to the bus. If this option is defined a
2116 custom i2c_init_board() routine in boards/xxx/board.c
2117 is run early in the boot sequence.
2119 CONFIG_I2C_MULTI_BUS
2121 This option allows the use of multiple I2C buses, each of which
2122 must have a controller. At any point in time, only one bus is
2123 active. To switch to a different bus, use the 'i2c dev' command.
2124 Note that bus numbering is zero-based.
2126 CONFIG_SYS_I2C_NOPROBES
2128 This option specifies a list of I2C devices that will be skipped
2129 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2130 is set, specify a list of bus-device pairs. Otherwise, specify
2131 a 1D array of device addresses
2134 #undef CONFIG_I2C_MULTI_BUS
2135 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2137 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2139 #define CONFIG_I2C_MULTI_BUS
2140 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2142 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2144 CONFIG_SYS_SPD_BUS_NUM
2146 If defined, then this indicates the I2C bus number for DDR SPD.
2147 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2149 CONFIG_SYS_RTC_BUS_NUM
2151 If defined, then this indicates the I2C bus number for the RTC.
2152 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2154 CONFIG_SOFT_I2C_READ_REPEATED_START
2156 defining this will force the i2c_read() function in
2157 the soft_i2c driver to perform an I2C repeated start
2158 between writing the address pointer and reading the
2159 data. If this define is omitted the default behaviour
2160 of doing a stop-start sequence will be used. Most I2C
2161 devices can use either method, but some require one or
2164 - SPI Support: CONFIG_SPI
2166 Enables SPI driver (so far only tested with
2167 SPI EEPROM, also an instance works with Crystal A/D and
2168 D/As on the SACSng board)
2172 Enables the driver for SPI controller on SuperH. Currently
2173 only SH7757 is supported.
2177 Enables a software (bit-bang) SPI driver rather than
2178 using hardware support. This is a general purpose
2179 driver that only requires three general I/O port pins
2180 (two outputs, one input) to function. If this is
2181 defined, the board configuration must define several
2182 SPI configuration items (port pins to use, etc). For
2183 an example, see include/configs/sacsng.h.
2187 Enables a hardware SPI driver for general-purpose reads
2188 and writes. As with CONFIG_SOFT_SPI, the board configuration
2189 must define a list of chip-select function pointers.
2190 Currently supported on some MPC8xxx processors. For an
2191 example, see include/configs/mpc8349emds.h.
2195 Enables the driver for the SPI controllers on i.MX and MXC
2196 SoCs. Currently i.MX31/35/51 are supported.
2198 CONFIG_SYS_SPI_MXC_WAIT
2199 Timeout for waiting until spi transfer completed.
2200 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2202 - FPGA Support: CONFIG_FPGA
2204 Enables FPGA subsystem.
2206 CONFIG_FPGA_<vendor>
2208 Enables support for specific chip vendors.
2211 CONFIG_FPGA_<family>
2213 Enables support for FPGA family.
2214 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2218 Specify the number of FPGA devices to support.
2220 CONFIG_SYS_FPGA_PROG_FEEDBACK
2222 Enable printing of hash marks during FPGA configuration.
2224 CONFIG_SYS_FPGA_CHECK_BUSY
2226 Enable checks on FPGA configuration interface busy
2227 status by the configuration function. This option
2228 will require a board or device specific function to
2233 If defined, a function that provides delays in the FPGA
2234 configuration driver.
2236 CONFIG_SYS_FPGA_CHECK_CTRLC
2237 Allow Control-C to interrupt FPGA configuration
2239 CONFIG_SYS_FPGA_CHECK_ERROR
2241 Check for configuration errors during FPGA bitfile
2242 loading. For example, abort during Virtex II
2243 configuration if the INIT_B line goes low (which
2244 indicated a CRC error).
2246 CONFIG_SYS_FPGA_WAIT_INIT
2248 Maximum time to wait for the INIT_B line to de-assert
2249 after PROB_B has been de-asserted during a Virtex II
2250 FPGA configuration sequence. The default time is 500
2253 CONFIG_SYS_FPGA_WAIT_BUSY
2255 Maximum time to wait for BUSY to de-assert during
2256 Virtex II FPGA configuration. The default is 5 ms.
2258 CONFIG_SYS_FPGA_WAIT_CONFIG
2260 Time to wait after FPGA configuration. The default is
2263 - Configuration Management:
2266 Some SoCs need special image types (e.g. U-Boot binary
2267 with a special header) as build targets. By defining
2268 CONFIG_BUILD_TARGET in the SoC / board header, this
2269 special image will be automatically built upon calling
2274 If defined, this string will be added to the U-Boot
2275 version information (U_BOOT_VERSION)
2277 - Vendor Parameter Protection:
2279 U-Boot considers the values of the environment
2280 variables "serial#" (Board Serial Number) and
2281 "ethaddr" (Ethernet Address) to be parameters that
2282 are set once by the board vendor / manufacturer, and
2283 protects these variables from casual modification by
2284 the user. Once set, these variables are read-only,
2285 and write or delete attempts are rejected. You can
2286 change this behaviour:
2288 If CONFIG_ENV_OVERWRITE is #defined in your config
2289 file, the write protection for vendor parameters is
2290 completely disabled. Anybody can change or delete
2293 Alternatively, if you define _both_ an ethaddr in the
2294 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2295 Ethernet address is installed in the environment,
2296 which can be changed exactly ONCE by the user. [The
2297 serial# is unaffected by this, i. e. it remains
2300 The same can be accomplished in a more flexible way
2301 for any variable by configuring the type of access
2302 to allow for those variables in the ".flags" variable
2303 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2308 Define this variable to enable the reservation of
2309 "protected RAM", i. e. RAM which is not overwritten
2310 by U-Boot. Define CONFIG_PRAM to hold the number of
2311 kB you want to reserve for pRAM. You can overwrite
2312 this default value by defining an environment
2313 variable "pram" to the number of kB you want to
2314 reserve. Note that the board info structure will
2315 still show the full amount of RAM. If pRAM is
2316 reserved, a new environment variable "mem" will
2317 automatically be defined to hold the amount of
2318 remaining RAM in a form that can be passed as boot
2319 argument to Linux, for instance like that:
2321 setenv bootargs ... mem=\${mem}
2324 This way you can tell Linux not to use this memory,
2325 either, which results in a memory region that will
2326 not be affected by reboots.
2328 *WARNING* If your board configuration uses automatic
2329 detection of the RAM size, you must make sure that
2330 this memory test is non-destructive. So far, the
2331 following board configurations are known to be
2334 IVMS8, IVML24, SPD8xx,
2335 HERMES, IP860, RPXlite, LWMON,
2338 - Access to physical memory region (> 4GB)
2339 Some basic support is provided for operations on memory not
2340 normally accessible to U-Boot - e.g. some architectures
2341 support access to more than 4GB of memory on 32-bit
2342 machines using physical address extension or similar.
2343 Define CONFIG_PHYSMEM to access this basic support, which
2344 currently only supports clearing the memory.
2349 Define this variable to stop the system in case of a
2350 fatal error, so that you have to reset it manually.
2351 This is probably NOT a good idea for an embedded
2352 system where you want the system to reboot
2353 automatically as fast as possible, but it may be
2354 useful during development since you can try to debug
2355 the conditions that lead to the situation.
2357 CONFIG_NET_RETRY_COUNT
2359 This variable defines the number of retries for
2360 network operations like ARP, RARP, TFTP, or BOOTP
2361 before giving up the operation. If not defined, a
2362 default value of 5 is used.
2366 Timeout waiting for an ARP reply in milliseconds.
2370 Timeout in milliseconds used in NFS protocol.
2371 If you encounter "ERROR: Cannot umount" in nfs command,
2372 try longer timeout such as
2373 #define CONFIG_NFS_TIMEOUT 10000UL
2375 - Command Interpreter:
2376 CONFIG_AUTO_COMPLETE
2378 Enable auto completion of commands using TAB.
2380 CONFIG_SYS_PROMPT_HUSH_PS2
2382 This defines the secondary prompt string, which is
2383 printed when the command interpreter needs more input
2384 to complete a command. Usually "> ".
2388 In the current implementation, the local variables
2389 space and global environment variables space are
2390 separated. Local variables are those you define by
2391 simply typing `name=value'. To access a local
2392 variable later on, you have write `$name' or
2393 `${name}'; to execute the contents of a variable
2394 directly type `$name' at the command prompt.
2396 Global environment variables are those you use
2397 setenv/printenv to work with. To run a command stored
2398 in such a variable, you need to use the run command,
2399 and you must not use the '$' sign to access them.
2401 To store commands and special characters in a
2402 variable, please use double quotation marks
2403 surrounding the whole text of the variable, instead
2404 of the backslashes before semicolons and special
2407 - Command Line Editing and History:
2408 CONFIG_CMDLINE_EDITING
2410 Enable editing and History functions for interactive
2411 command line input operations
2413 - Command Line PS1/PS2 support:
2414 CONFIG_CMDLINE_PS_SUPPORT
2416 Enable support for changing the command prompt string
2417 at run-time. Only static string is supported so far.
2418 The string is obtained from environment variables PS1
2421 - Default Environment:
2422 CONFIG_EXTRA_ENV_SETTINGS
2424 Define this to contain any number of null terminated
2425 strings (variable = value pairs) that will be part of
2426 the default environment compiled into the boot image.
2428 For example, place something like this in your
2429 board's config file:
2431 #define CONFIG_EXTRA_ENV_SETTINGS \
2435 Warning: This method is based on knowledge about the
2436 internal format how the environment is stored by the
2437 U-Boot code. This is NOT an official, exported
2438 interface! Although it is unlikely that this format
2439 will change soon, there is no guarantee either.
2440 You better know what you are doing here.
2442 Note: overly (ab)use of the default environment is
2443 discouraged. Make sure to check other ways to preset
2444 the environment like the "source" command or the
2447 CONFIG_ENV_VARS_UBOOT_CONFIG
2449 Define this in order to add variables describing the
2450 U-Boot build configuration to the default environment.
2451 These will be named arch, cpu, board, vendor, and soc.
2453 Enabling this option will cause the following to be defined:
2461 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2463 Define this in order to add variables describing certain
2464 run-time determined information about the hardware to the
2465 environment. These will be named board_name, board_rev.
2467 CONFIG_DELAY_ENVIRONMENT
2469 Normally the environment is loaded when the board is
2470 initialised so that it is available to U-Boot. This inhibits
2471 that so that the environment is not available until
2472 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2473 this is instead controlled by the value of
2474 /config/load-environment.
2476 - DataFlash Support:
2477 CONFIG_HAS_DATAFLASH
2479 Defining this option enables DataFlash features and
2480 allows to read/write in Dataflash via the standard
2483 - Serial Flash support
2486 Defining this option enables SPI flash commands
2487 'sf probe/read/write/erase/update'.
2489 Usage requires an initial 'probe' to define the serial
2490 flash parameters, followed by read/write/erase/update
2493 The following defaults may be provided by the platform
2494 to handle the common case when only a single serial
2495 flash is present on the system.
2497 CONFIG_SF_DEFAULT_BUS Bus identifier
2498 CONFIG_SF_DEFAULT_CS Chip-select
2499 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2500 CONFIG_SF_DEFAULT_SPEED in Hz
2504 Define this option to include a destructive SPI flash
2507 - SystemACE Support:
2510 Adding this option adds support for Xilinx SystemACE
2511 chips attached via some sort of local bus. The address
2512 of the chip must also be defined in the
2513 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2515 #define CONFIG_SYSTEMACE
2516 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2518 When SystemACE support is added, the "ace" device type
2519 becomes available to the fat commands, i.e. fatls.
2521 - TFTP Fixed UDP Port:
2524 If this is defined, the environment variable tftpsrcp
2525 is used to supply the TFTP UDP source port value.
2526 If tftpsrcp isn't defined, the normal pseudo-random port
2527 number generator is used.
2529 Also, the environment variable tftpdstp is used to supply
2530 the TFTP UDP destination port value. If tftpdstp isn't
2531 defined, the normal port 69 is used.
2533 The purpose for tftpsrcp is to allow a TFTP server to
2534 blindly start the TFTP transfer using the pre-configured
2535 target IP address and UDP port. This has the effect of
2536 "punching through" the (Windows XP) firewall, allowing
2537 the remainder of the TFTP transfer to proceed normally.
2538 A better solution is to properly configure the firewall,
2539 but sometimes that is not allowed.
2541 - bootcount support:
2542 CONFIG_BOOTCOUNT_LIMIT
2544 This enables the bootcounter support, see:
2545 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2548 enable special bootcounter support on at91sam9xe based boards.
2550 enable special bootcounter support on da850 based boards.
2551 CONFIG_BOOTCOUNT_RAM
2552 enable support for the bootcounter in RAM
2553 CONFIG_BOOTCOUNT_I2C
2554 enable support for the bootcounter on an i2c (like RTC) device.
2555 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2556 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2558 CONFIG_BOOTCOUNT_ALEN = address len
2560 - Show boot progress:
2561 CONFIG_SHOW_BOOT_PROGRESS
2563 Defining this option allows to add some board-
2564 specific code (calling a user-provided function
2565 "show_boot_progress(int)") that enables you to show
2566 the system's boot progress on some display (for
2567 example, some LED's) on your board. At the moment,
2568 the following checkpoints are implemented:
2571 Legacy uImage format:
2574 1 common/cmd_bootm.c before attempting to boot an image
2575 -1 common/cmd_bootm.c Image header has bad magic number
2576 2 common/cmd_bootm.c Image header has correct magic number
2577 -2 common/cmd_bootm.c Image header has bad checksum
2578 3 common/cmd_bootm.c Image header has correct checksum
2579 -3 common/cmd_bootm.c Image data has bad checksum
2580 4 common/cmd_bootm.c Image data has correct checksum
2581 -4 common/cmd_bootm.c Image is for unsupported architecture
2582 5 common/cmd_bootm.c Architecture check OK
2583 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2584 6 common/cmd_bootm.c Image Type check OK
2585 -6 common/cmd_bootm.c gunzip uncompression error
2586 -7 common/cmd_bootm.c Unimplemented compression type
2587 7 common/cmd_bootm.c Uncompression OK
2588 8 common/cmd_bootm.c No uncompress/copy overwrite error
2589 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2591 9 common/image.c Start initial ramdisk verification
2592 -10 common/image.c Ramdisk header has bad magic number
2593 -11 common/image.c Ramdisk header has bad checksum
2594 10 common/image.c Ramdisk header is OK
2595 -12 common/image.c Ramdisk data has bad checksum
2596 11 common/image.c Ramdisk data has correct checksum
2597 12 common/image.c Ramdisk verification complete, start loading
2598 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2599 13 common/image.c Start multifile image verification
2600 14 common/image.c No initial ramdisk, no multifile, continue.
2602 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2604 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2605 -31 post/post.c POST test failed, detected by post_output_backlog()
2606 -32 post/post.c POST test failed, detected by post_run_single()
2608 34 common/cmd_doc.c before loading a Image from a DOC device
2609 -35 common/cmd_doc.c Bad usage of "doc" command
2610 35 common/cmd_doc.c correct usage of "doc" command
2611 -36 common/cmd_doc.c No boot device
2612 36 common/cmd_doc.c correct boot device
2613 -37 common/cmd_doc.c Unknown Chip ID on boot device
2614 37 common/cmd_doc.c correct chip ID found, device available
2615 -38 common/cmd_doc.c Read Error on boot device
2616 38 common/cmd_doc.c reading Image header from DOC device OK
2617 -39 common/cmd_doc.c Image header has bad magic number
2618 39 common/cmd_doc.c Image header has correct magic number
2619 -40 common/cmd_doc.c Error reading Image from DOC device
2620 40 common/cmd_doc.c Image header has correct magic number
2621 41 common/cmd_ide.c before loading a Image from a IDE device
2622 -42 common/cmd_ide.c Bad usage of "ide" command
2623 42 common/cmd_ide.c correct usage of "ide" command
2624 -43 common/cmd_ide.c No boot device
2625 43 common/cmd_ide.c boot device found
2626 -44 common/cmd_ide.c Device not available
2627 44 common/cmd_ide.c Device available
2628 -45 common/cmd_ide.c wrong partition selected
2629 45 common/cmd_ide.c partition selected
2630 -46 common/cmd_ide.c Unknown partition table
2631 46 common/cmd_ide.c valid partition table found
2632 -47 common/cmd_ide.c Invalid partition type
2633 47 common/cmd_ide.c correct partition type
2634 -48 common/cmd_ide.c Error reading Image Header on boot device
2635 48 common/cmd_ide.c reading Image Header from IDE device OK
2636 -49 common/cmd_ide.c Image header has bad magic number
2637 49 common/cmd_ide.c Image header has correct magic number
2638 -50 common/cmd_ide.c Image header has bad checksum
2639 50 common/cmd_ide.c Image header has correct checksum
2640 -51 common/cmd_ide.c Error reading Image from IDE device
2641 51 common/cmd_ide.c reading Image from IDE device OK
2642 52 common/cmd_nand.c before loading a Image from a NAND device
2643 -53 common/cmd_nand.c Bad usage of "nand" command
2644 53 common/cmd_nand.c correct usage of "nand" command
2645 -54 common/cmd_nand.c No boot device
2646 54 common/cmd_nand.c boot device found
2647 -55 common/cmd_nand.c Unknown Chip ID on boot device
2648 55 common/cmd_nand.c correct chip ID found, device available
2649 -56 common/cmd_nand.c Error reading Image Header on boot device
2650 56 common/cmd_nand.c reading Image Header from NAND device OK
2651 -57 common/cmd_nand.c Image header has bad magic number
2652 57 common/cmd_nand.c Image header has correct magic number
2653 -58 common/cmd_nand.c Error reading Image from NAND device
2654 58 common/cmd_nand.c reading Image from NAND device OK
2656 -60 common/env_common.c Environment has a bad CRC, using default
2658 64 net/eth.c starting with Ethernet configuration.
2659 -64 net/eth.c no Ethernet found.
2660 65 net/eth.c Ethernet found.
2662 -80 common/cmd_net.c usage wrong
2663 80 common/cmd_net.c before calling net_loop()
2664 -81 common/cmd_net.c some error in net_loop() occurred
2665 81 common/cmd_net.c net_loop() back without error
2666 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2667 82 common/cmd_net.c trying automatic boot
2668 83 common/cmd_net.c running "source" command
2669 -83 common/cmd_net.c some error in automatic boot or "source" command
2670 84 common/cmd_net.c end without errors
2675 100 common/cmd_bootm.c Kernel FIT Image has correct format
2676 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2677 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2678 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2679 102 common/cmd_bootm.c Kernel unit name specified
2680 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2681 103 common/cmd_bootm.c Found configuration node
2682 104 common/cmd_bootm.c Got kernel subimage node offset
2683 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2684 105 common/cmd_bootm.c Kernel subimage hash verification OK
2685 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2686 106 common/cmd_bootm.c Architecture check OK
2687 -106 common/cmd_bootm.c Kernel subimage has wrong type
2688 107 common/cmd_bootm.c Kernel subimage type OK
2689 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2690 108 common/cmd_bootm.c Got kernel subimage data/size
2691 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2692 -109 common/cmd_bootm.c Can't get kernel subimage type
2693 -110 common/cmd_bootm.c Can't get kernel subimage comp
2694 -111 common/cmd_bootm.c Can't get kernel subimage os
2695 -112 common/cmd_bootm.c Can't get kernel subimage load address
2696 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2698 120 common/image.c Start initial ramdisk verification
2699 -120 common/image.c Ramdisk FIT image has incorrect format
2700 121 common/image.c Ramdisk FIT image has correct format
2701 122 common/image.c No ramdisk subimage unit name, using configuration
2702 -122 common/image.c Can't get configuration for ramdisk subimage
2703 123 common/image.c Ramdisk unit name specified
2704 -124 common/image.c Can't get ramdisk subimage node offset
2705 125 common/image.c Got ramdisk subimage node offset
2706 -125 common/image.c Ramdisk subimage hash verification failed
2707 126 common/image.c Ramdisk subimage hash verification OK
2708 -126 common/image.c Ramdisk subimage for unsupported architecture
2709 127 common/image.c Architecture check OK
2710 -127 common/image.c Can't get ramdisk subimage data/size
2711 128 common/image.c Got ramdisk subimage data/size
2712 129 common/image.c Can't get ramdisk load address
2713 -129 common/image.c Got ramdisk load address
2715 -130 common/cmd_doc.c Incorrect FIT image format
2716 131 common/cmd_doc.c FIT image format OK
2718 -140 common/cmd_ide.c Incorrect FIT image format
2719 141 common/cmd_ide.c FIT image format OK
2721 -150 common/cmd_nand.c Incorrect FIT image format
2722 151 common/cmd_nand.c FIT image format OK
2724 - legacy image format:
2725 CONFIG_IMAGE_FORMAT_LEGACY
2726 enables the legacy image format support in U-Boot.
2729 enabled if CONFIG_FIT_SIGNATURE is not defined.
2731 CONFIG_DISABLE_IMAGE_LEGACY
2732 disable the legacy image format
2734 This define is introduced, as the legacy image format is
2735 enabled per default for backward compatibility.
2737 - Standalone program support:
2738 CONFIG_STANDALONE_LOAD_ADDR
2740 This option defines a board specific value for the
2741 address where standalone program gets loaded, thus
2742 overwriting the architecture dependent default
2745 - Frame Buffer Address:
2748 Define CONFIG_FB_ADDR if you want to use specific
2749 address for frame buffer. This is typically the case
2750 when using a graphics controller has separate video
2751 memory. U-Boot will then place the frame buffer at
2752 the given address instead of dynamically reserving it
2753 in system RAM by calling lcd_setmem(), which grabs
2754 the memory for the frame buffer depending on the
2755 configured panel size.
2757 Please see board_init_f function.
2759 - Automatic software updates via TFTP server
2761 CONFIG_UPDATE_TFTP_CNT_MAX
2762 CONFIG_UPDATE_TFTP_MSEC_MAX
2764 These options enable and control the auto-update feature;
2765 for a more detailed description refer to doc/README.update.
2767 - MTD Support (mtdparts command, UBI support)
2770 Adds the MTD device infrastructure from the Linux kernel.
2771 Needed for mtdparts command support.
2773 CONFIG_MTD_PARTITIONS
2775 Adds the MTD partitioning infrastructure from the Linux
2776 kernel. Needed for UBI support.
2779 CONFIG_UBI_SILENCE_MSG
2781 Make the verbose messages from UBI stop printing. This leaves
2782 warnings and errors enabled.
2785 CONFIG_MTD_UBI_WL_THRESHOLD
2786 This parameter defines the maximum difference between the highest
2787 erase counter value and the lowest erase counter value of eraseblocks
2788 of UBI devices. When this threshold is exceeded, UBI starts performing
2789 wear leveling by means of moving data from eraseblock with low erase
2790 counter to eraseblocks with high erase counter.
2792 The default value should be OK for SLC NAND flashes, NOR flashes and
2793 other flashes which have eraseblock life-cycle 100000 or more.
2794 However, in case of MLC NAND flashes which typically have eraseblock
2795 life-cycle less than 10000, the threshold should be lessened (e.g.,
2796 to 128 or 256, although it does not have to be power of 2).
2800 CONFIG_MTD_UBI_BEB_LIMIT
2801 This option specifies the maximum bad physical eraseblocks UBI
2802 expects on the MTD device (per 1024 eraseblocks). If the
2803 underlying flash does not admit of bad eraseblocks (e.g. NOR
2804 flash), this value is ignored.
2806 NAND datasheets often specify the minimum and maximum NVM
2807 (Number of Valid Blocks) for the flashes' endurance lifetime.
2808 The maximum expected bad eraseblocks per 1024 eraseblocks
2809 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2810 which gives 20 for most NANDs (MaxNVB is basically the total
2811 count of eraseblocks on the chip).
2813 To put it differently, if this value is 20, UBI will try to
2814 reserve about 1.9% of physical eraseblocks for bad blocks
2815 handling. And that will be 1.9% of eraseblocks on the entire
2816 NAND chip, not just the MTD partition UBI attaches. This means
2817 that if you have, say, a NAND flash chip admits maximum 40 bad
2818 eraseblocks, and it is split on two MTD partitions of the same
2819 size, UBI will reserve 40 eraseblocks when attaching a
2824 CONFIG_MTD_UBI_FASTMAP
2825 Fastmap is a mechanism which allows attaching an UBI device
2826 in nearly constant time. Instead of scanning the whole MTD device it
2827 only has to locate a checkpoint (called fastmap) on the device.
2828 The on-flash fastmap contains all information needed to attach
2829 the device. Using fastmap makes only sense on large devices where
2830 attaching by scanning takes long. UBI will not automatically install
2831 a fastmap on old images, but you can set the UBI parameter
2832 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2833 that fastmap-enabled images are still usable with UBI implementations
2834 without fastmap support. On typical flash devices the whole fastmap
2835 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2837 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2838 Set this parameter to enable fastmap automatically on images
2842 CONFIG_MTD_UBI_FM_DEBUG
2843 Enable UBI fastmap debug
2847 CONFIG_UBIFS_SILENCE_MSG
2849 Make the verbose messages from UBIFS stop printing. This leaves
2850 warnings and errors enabled.
2854 Enable building of SPL globally.
2857 LDSCRIPT for linking the SPL binary.
2859 CONFIG_SPL_MAX_FOOTPRINT
2860 Maximum size in memory allocated to the SPL, BSS included.
2861 When defined, the linker checks that the actual memory
2862 used by SPL from _start to __bss_end does not exceed it.
2863 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2864 must not be both defined at the same time.
2867 Maximum size of the SPL image (text, data, rodata, and
2868 linker lists sections), BSS excluded.
2869 When defined, the linker checks that the actual size does
2872 CONFIG_SPL_TEXT_BASE
2873 TEXT_BASE for linking the SPL binary.
2875 CONFIG_SPL_RELOC_TEXT_BASE
2876 Address to relocate to. If unspecified, this is equal to
2877 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2879 CONFIG_SPL_BSS_START_ADDR
2880 Link address for the BSS within the SPL binary.
2882 CONFIG_SPL_BSS_MAX_SIZE
2883 Maximum size in memory allocated to the SPL BSS.
2884 When defined, the linker checks that the actual memory used
2885 by SPL from __bss_start to __bss_end does not exceed it.
2886 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2887 must not be both defined at the same time.
2890 Adress of the start of the stack SPL will use
2892 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2893 When defined, SPL will panic() if the image it has
2894 loaded does not have a signature.
2895 Defining this is useful when code which loads images
2896 in SPL cannot guarantee that absolutely all read errors
2898 An example is the LPC32XX MLC NAND driver, which will
2899 consider that a completely unreadable NAND block is bad,
2900 and thus should be skipped silently.
2902 CONFIG_SPL_RELOC_STACK
2903 Adress of the start of the stack SPL will use after
2904 relocation. If unspecified, this is equal to
2907 CONFIG_SYS_SPL_MALLOC_START
2908 Starting address of the malloc pool used in SPL.
2909 When this option is set the full malloc is used in SPL and
2910 it is set up by spl_init() and before that, the simple malloc()
2911 can be used if CONFIG_SYS_MALLOC_F is defined.
2913 CONFIG_SYS_SPL_MALLOC_SIZE
2914 The size of the malloc pool used in SPL.
2916 CONFIG_SPL_FRAMEWORK
2917 Enable the SPL framework under common/. This framework
2918 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2919 NAND loading of the Linux Kernel.
2922 Enable booting directly to an OS from SPL.
2923 See also: doc/README.falcon
2925 CONFIG_SPL_DISPLAY_PRINT
2926 For ARM, enable an optional function to print more information
2927 about the running system.
2929 CONFIG_SPL_INIT_MINIMAL
2930 Arch init code should be built for a very small image
2932 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2933 Partition on the MMC to load U-Boot from when the MMC is being
2936 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2937 Sector to load kernel uImage from when MMC is being
2938 used in raw mode (for Falcon mode)
2940 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2941 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2942 Sector and number of sectors to load kernel argument
2943 parameters from when MMC is being used in raw mode
2946 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2947 Partition on the MMC to load U-Boot from when the MMC is being
2950 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2951 Filename to read to load U-Boot when reading from filesystem
2953 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2954 Filename to read to load kernel uImage when reading
2955 from filesystem (for Falcon mode)
2957 CONFIG_SPL_FS_LOAD_ARGS_NAME
2958 Filename to read to load kernel argument parameters
2959 when reading from filesystem (for Falcon mode)
2961 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2962 Set this for NAND SPL on PPC mpc83xx targets, so that
2963 start.S waits for the rest of the SPL to load before
2964 continuing (the hardware starts execution after just
2965 loading the first page rather than the full 4K).
2967 CONFIG_SPL_SKIP_RELOCATE
2968 Avoid SPL relocation
2970 CONFIG_SPL_NAND_BASE
2971 Include nand_base.c in the SPL. Requires
2972 CONFIG_SPL_NAND_DRIVERS.
2974 CONFIG_SPL_NAND_DRIVERS
2975 SPL uses normal NAND drivers, not minimal drivers.
2978 Include standard software ECC in the SPL
2980 CONFIG_SPL_NAND_SIMPLE
2981 Support for NAND boot using simple NAND drivers that
2982 expose the cmd_ctrl() interface.
2985 Support for a lightweight UBI (fastmap) scanner and
2988 CONFIG_SPL_NAND_RAW_ONLY
2989 Support to boot only raw u-boot.bin images. Use this only
2990 if you need to save space.
2992 CONFIG_SPL_COMMON_INIT_DDR
2993 Set for common ddr init with serial presence detect in
2996 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2997 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2998 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2999 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3000 CONFIG_SYS_NAND_ECCBYTES
3001 Defines the size and behavior of the NAND that SPL uses
3004 CONFIG_SPL_NAND_BOOT
3005 Add support NAND boot
3007 CONFIG_SYS_NAND_U_BOOT_OFFS
3008 Location in NAND to read U-Boot from
3010 CONFIG_SYS_NAND_U_BOOT_DST
3011 Location in memory to load U-Boot to
3013 CONFIG_SYS_NAND_U_BOOT_SIZE
3014 Size of image to load
3016 CONFIG_SYS_NAND_U_BOOT_START
3017 Entry point in loaded image to jump to
3019 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3020 Define this if you need to first read the OOB and then the
3021 data. This is used, for example, on davinci platforms.
3023 CONFIG_SPL_OMAP3_ID_NAND
3024 Support for an OMAP3-specific set of functions to return the
3025 ID and MFR of the first attached NAND chip, if present.
3027 CONFIG_SPL_RAM_DEVICE
3028 Support for running image already present in ram, in SPL binary
3031 Image offset to which the SPL should be padded before appending
3032 the SPL payload. By default, this is defined as
3033 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3034 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3035 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3038 Final target image containing SPL and payload. Some SPLs
3039 use an arch-specific makefile fragment instead, for
3040 example if more than one image needs to be produced.
3042 CONFIG_FIT_SPL_PRINT
3043 Printing information about a FIT image adds quite a bit of
3044 code to SPL. So this is normally disabled in SPL. Use this
3045 option to re-enable it. This will affect the output of the
3046 bootm command when booting a FIT image.
3050 Enable building of TPL globally.
3053 Image offset to which the TPL should be padded before appending
3054 the TPL payload. By default, this is defined as
3055 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3056 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3057 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3059 - Interrupt support (PPC):
3061 There are common interrupt_init() and timer_interrupt()
3062 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3063 for CPU specific initialization. interrupt_init_cpu()
3064 should set decrementer_count to appropriate value. If
3065 CPU resets decrementer automatically after interrupt
3066 (ppc4xx) it should set decrementer_count to zero.
3067 timer_interrupt() calls timer_interrupt_cpu() for CPU
3068 specific handling. If board has watchdog / status_led
3069 / other_activity_monitor it works automatically from
3070 general timer_interrupt().
3073 Board initialization settings:
3074 ------------------------------
3076 During Initialization u-boot calls a number of board specific functions
3077 to allow the preparation of board specific prerequisites, e.g. pin setup
3078 before drivers are initialized. To enable these callbacks the
3079 following configuration macros have to be defined. Currently this is
3080 architecture specific, so please check arch/your_architecture/lib/board.c
3081 typically in board_init_f() and board_init_r().
3083 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3084 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3085 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3086 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3088 Configuration Settings:
3089 -----------------------
3091 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3092 Optionally it can be defined to support 64-bit memory commands.
3094 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3095 undefine this when you're short of memory.
3097 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3098 width of the commands listed in the 'help' command output.
3100 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3101 prompt for user input.
3103 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3105 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3107 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3109 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3110 the application (usually a Linux kernel) when it is
3113 - CONFIG_SYS_BAUDRATE_TABLE:
3114 List of legal baudrate settings for this board.
3116 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3117 Begin and End addresses of the area used by the
3120 - CONFIG_SYS_ALT_MEMTEST:
3121 Enable an alternate, more extensive memory test.
3123 - CONFIG_SYS_MEMTEST_SCRATCH:
3124 Scratch address used by the alternate memory test
3125 You only need to set this if address zero isn't writeable
3127 - CONFIG_SYS_MEM_RESERVE_SECURE
3128 Only implemented for ARMv8 for now.
3129 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3130 is substracted from total RAM and won't be reported to OS.
3131 This memory can be used as secure memory. A variable
3132 gd->arch.secure_ram is used to track the location. In systems
3133 the RAM base is not zero, or RAM is divided into banks,
3134 this variable needs to be recalcuated to get the address.
3136 - CONFIG_SYS_MEM_TOP_HIDE:
3137 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3138 this specified memory area will get subtracted from the top
3139 (end) of RAM and won't get "touched" at all by U-Boot. By
3140 fixing up gd->ram_size the Linux kernel should gets passed
3141 the now "corrected" memory size and won't touch it either.
3142 This should work for arch/ppc and arch/powerpc. Only Linux
3143 board ports in arch/powerpc with bootwrapper support that
3144 recalculate the memory size from the SDRAM controller setup
3145 will have to get fixed in Linux additionally.
3147 This option can be used as a workaround for the 440EPx/GRx
3148 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3151 WARNING: Please make sure that this value is a multiple of
3152 the Linux page size (normally 4k). If this is not the case,
3153 then the end address of the Linux memory will be located at a
3154 non page size aligned address and this could cause major
3157 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3158 Enable temporary baudrate change while serial download
3160 - CONFIG_SYS_SDRAM_BASE:
3161 Physical start address of SDRAM. _Must_ be 0 here.
3163 - CONFIG_SYS_FLASH_BASE:
3164 Physical start address of Flash memory.
3166 - CONFIG_SYS_MONITOR_BASE:
3167 Physical start address of boot monitor code (set by
3168 make config files to be same as the text base address
3169 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3170 CONFIG_SYS_FLASH_BASE when booting from flash.
3172 - CONFIG_SYS_MONITOR_LEN:
3173 Size of memory reserved for monitor code, used to
3174 determine _at_compile_time_ (!) if the environment is
3175 embedded within the U-Boot image, or in a separate
3178 - CONFIG_SYS_MALLOC_LEN:
3179 Size of DRAM reserved for malloc() use.
3181 - CONFIG_SYS_MALLOC_F_LEN
3182 Size of the malloc() pool for use before relocation. If
3183 this is defined, then a very simple malloc() implementation
3184 will become available before relocation. The address is just
3185 below the global data, and the stack is moved down to make
3188 This feature allocates regions with increasing addresses
3189 within the region. calloc() is supported, but realloc()
3190 is not available. free() is supported but does nothing.
3191 The memory will be freed (or in fact just forgotten) when
3192 U-Boot relocates itself.
3194 - CONFIG_SYS_MALLOC_SIMPLE
3195 Provides a simple and small malloc() and calloc() for those
3196 boards which do not use the full malloc in SPL (which is
3197 enabled with CONFIG_SYS_SPL_MALLOC_START).
3199 - CONFIG_SYS_NONCACHED_MEMORY:
3200 Size of non-cached memory area. This area of memory will be
3201 typically located right below the malloc() area and mapped
3202 uncached in the MMU. This is useful for drivers that would
3203 otherwise require a lot of explicit cache maintenance. For
3204 some drivers it's also impossible to properly maintain the
3205 cache. For example if the regions that need to be flushed
3206 are not a multiple of the cache-line size, *and* padding
3207 cannot be allocated between the regions to align them (i.e.
3208 if the HW requires a contiguous array of regions, and the
3209 size of each region is not cache-aligned), then a flush of
3210 one region may result in overwriting data that hardware has
3211 written to another region in the same cache-line. This can
3212 happen for example in network drivers where descriptors for
3213 buffers are typically smaller than the CPU cache-line (e.g.
3214 16 bytes vs. 32 or 64 bytes).
3216 Non-cached memory is only supported on 32-bit ARM at present.
3218 - CONFIG_SYS_BOOTM_LEN:
3219 Normally compressed uImages are limited to an
3220 uncompressed size of 8 MBytes. If this is not enough,
3221 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3222 to adjust this setting to your needs.
3224 - CONFIG_SYS_BOOTMAPSZ:
3225 Maximum size of memory mapped by the startup code of
3226 the Linux kernel; all data that must be processed by
3227 the Linux kernel (bd_info, boot arguments, FDT blob if
3228 used) must be put below this limit, unless "bootm_low"
3229 environment variable is defined and non-zero. In such case
3230 all data for the Linux kernel must be between "bootm_low"
3231 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3232 variable "bootm_mapsize" will override the value of
3233 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3234 then the value in "bootm_size" will be used instead.
3236 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3237 Enable initrd_high functionality. If defined then the
3238 initrd_high feature is enabled and the bootm ramdisk subcommand
3241 - CONFIG_SYS_BOOT_GET_CMDLINE:
3242 Enables allocating and saving kernel cmdline in space between
3243 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3245 - CONFIG_SYS_BOOT_GET_KBD:
3246 Enables allocating and saving a kernel copy of the bd_info in
3247 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3249 - CONFIG_SYS_MAX_FLASH_BANKS:
3250 Max number of Flash memory banks
3252 - CONFIG_SYS_MAX_FLASH_SECT:
3253 Max number of sectors on a Flash chip
3255 - CONFIG_SYS_FLASH_ERASE_TOUT:
3256 Timeout for Flash erase operations (in ms)
3258 - CONFIG_SYS_FLASH_WRITE_TOUT:
3259 Timeout for Flash write operations (in ms)
3261 - CONFIG_SYS_FLASH_LOCK_TOUT
3262 Timeout for Flash set sector lock bit operation (in ms)
3264 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3265 Timeout for Flash clear lock bits operation (in ms)
3267 - CONFIG_SYS_FLASH_PROTECTION
3268 If defined, hardware flash sectors protection is used
3269 instead of U-Boot software protection.
3271 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3273 Enable TFTP transfers directly to flash memory;
3274 without this option such a download has to be
3275 performed in two steps: (1) download to RAM, and (2)
3276 copy from RAM to flash.
3278 The two-step approach is usually more reliable, since
3279 you can check if the download worked before you erase
3280 the flash, but in some situations (when system RAM is
3281 too limited to allow for a temporary copy of the
3282 downloaded image) this option may be very useful.
3284 - CONFIG_SYS_FLASH_CFI:
3285 Define if the flash driver uses extra elements in the
3286 common flash structure for storing flash geometry.
3288 - CONFIG_FLASH_CFI_DRIVER
3289 This option also enables the building of the cfi_flash driver
3290 in the drivers directory
3292 - CONFIG_FLASH_CFI_MTD
3293 This option enables the building of the cfi_mtd driver
3294 in the drivers directory. The driver exports CFI flash
3297 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3298 Use buffered writes to flash.
3300 - CONFIG_FLASH_SPANSION_S29WS_N
3301 s29ws-n MirrorBit flash has non-standard addresses for buffered
3304 - CONFIG_SYS_FLASH_QUIET_TEST
3305 If this option is defined, the common CFI flash doesn't
3306 print it's warning upon not recognized FLASH banks. This
3307 is useful, if some of the configured banks are only
3308 optionally available.
3310 - CONFIG_FLASH_SHOW_PROGRESS
3311 If defined (must be an integer), print out countdown
3312 digits and dots. Recommended value: 45 (9..1) for 80
3313 column displays, 15 (3..1) for 40 column displays.
3315 - CONFIG_FLASH_VERIFY
3316 If defined, the content of the flash (destination) is compared
3317 against the source after the write operation. An error message
3318 will be printed when the contents are not identical.
3319 Please note that this option is useless in nearly all cases,
3320 since such flash programming errors usually are detected earlier
3321 while unprotecting/erasing/programming. Please only enable
3322 this option if you really know what you are doing.
3324 - CONFIG_SYS_RX_ETH_BUFFER:
3325 Defines the number of Ethernet receive buffers. On some
3326 Ethernet controllers it is recommended to set this value
3327 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3328 buffers can be full shortly after enabling the interface
3329 on high Ethernet traffic.
3330 Defaults to 4 if not defined.
3332 - CONFIG_ENV_MAX_ENTRIES
3334 Maximum number of entries in the hash table that is used
3335 internally to store the environment settings. The default
3336 setting is supposed to be generous and should work in most
3337 cases. This setting can be used to tune behaviour; see
3338 lib/hashtable.c for details.
3340 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3341 - CONFIG_ENV_FLAGS_LIST_STATIC
3342 Enable validation of the values given to environment variables when
3343 calling env set. Variables can be restricted to only decimal,
3344 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3345 the variables can also be restricted to IP address or MAC address.
3347 The format of the list is:
3348 type_attribute = [s|d|x|b|i|m]
3349 access_attribute = [a|r|o|c]
3350 attributes = type_attribute[access_attribute]
3351 entry = variable_name[:attributes]
3354 The type attributes are:
3355 s - String (default)
3358 b - Boolean ([1yYtT|0nNfF])
3362 The access attributes are:
3368 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3369 Define this to a list (string) to define the ".flags"
3370 environment variable in the default or embedded environment.
3372 - CONFIG_ENV_FLAGS_LIST_STATIC
3373 Define this to a list (string) to define validation that
3374 should be done if an entry is not found in the ".flags"
3375 environment variable. To override a setting in the static
3376 list, simply add an entry for the same variable name to the
3379 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3380 regular expression. This allows multiple variables to define the same
3381 flags without explicitly listing them for each variable.
3383 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3384 If defined, don't allow the -f switch to env set override variable
3388 If stdint.h is available with your toolchain you can define this
3389 option to enable it. You can provide option 'USE_STDINT=1' when
3390 building U-Boot to enable this.
3392 The following definitions that deal with the placement and management
3393 of environment data (variable area); in general, we support the
3394 following configurations:
3396 - CONFIG_BUILD_ENVCRC:
3398 Builds up envcrc with the target environment so that external utils
3399 may easily extract it and embed it in final U-Boot images.
3401 BE CAREFUL! The first access to the environment happens quite early
3402 in U-Boot initialization (when we try to get the setting of for the
3403 console baudrate). You *MUST* have mapped your NVRAM area then, or
3406 Please note that even with NVRAM we still use a copy of the
3407 environment in RAM: we could work on NVRAM directly, but we want to
3408 keep settings there always unmodified except somebody uses "saveenv"
3409 to save the current settings.
3411 BE CAREFUL! For some special cases, the local device can not use
3412 "saveenv" command. For example, the local device will get the
3413 environment stored in a remote NOR flash by SRIO or PCIE link,
3414 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3416 - CONFIG_NAND_ENV_DST
3418 Defines address in RAM to which the nand_spl code should copy the
3419 environment. If redundant environment is used, it will be copied to
3420 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3422 Please note that the environment is read-only until the monitor
3423 has been relocated to RAM and a RAM copy of the environment has been
3424 created; also, when using EEPROM you will have to use getenv_f()
3425 until then to read environment variables.
3427 The environment is protected by a CRC32 checksum. Before the monitor
3428 is relocated into RAM, as a result of a bad CRC you will be working
3429 with the compiled-in default environment - *silently*!!! [This is
3430 necessary, because the first environment variable we need is the
3431 "baudrate" setting for the console - if we have a bad CRC, we don't
3432 have any device yet where we could complain.]
3434 Note: once the monitor has been relocated, then it will complain if
3435 the default environment is used; a new CRC is computed as soon as you
3436 use the "saveenv" command to store a valid environment.
3438 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3439 Echo the inverted Ethernet link state to the fault LED.
3441 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3442 also needs to be defined.
3444 - CONFIG_SYS_FAULT_MII_ADDR:
3445 MII address of the PHY to check for the Ethernet link state.
3447 - CONFIG_NS16550_MIN_FUNCTIONS:
3448 Define this if you desire to only have use of the NS16550_init
3449 and NS16550_putc functions for the serial driver located at
3450 drivers/serial/ns16550.c. This option is useful for saving
3451 space for already greatly restricted images, including but not
3452 limited to NAND_SPL configurations.
3454 - CONFIG_DISPLAY_BOARDINFO
3455 Display information about the board that U-Boot is running on
3456 when U-Boot starts up. The board function checkboard() is called
3459 - CONFIG_DISPLAY_BOARDINFO_LATE
3460 Similar to the previous option, but display this information
3461 later, once stdio is running and output goes to the LCD, if
3464 - CONFIG_BOARD_SIZE_LIMIT:
3465 Maximum size of the U-Boot image. When defined, the
3466 build system checks that the actual size does not
3469 Low Level (hardware related) configuration options:
3470 ---------------------------------------------------
3472 - CONFIG_SYS_CACHELINE_SIZE:
3473 Cache Line Size of the CPU.
3475 - CONFIG_SYS_CCSRBAR_DEFAULT:
3476 Default (power-on reset) physical address of CCSR on Freescale
3479 - CONFIG_SYS_CCSRBAR:
3480 Virtual address of CCSR. On a 32-bit build, this is typically
3481 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3483 - CONFIG_SYS_CCSRBAR_PHYS:
3484 Physical address of CCSR. CCSR can be relocated to a new
3485 physical address, if desired. In this case, this macro should
3486 be set to that address. Otherwise, it should be set to the
3487 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3488 is typically relocated on 36-bit builds. It is recommended
3489 that this macro be defined via the _HIGH and _LOW macros:
3491 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3492 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3494 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3495 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3496 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3497 used in assembly code, so it must not contain typecasts or
3498 integer size suffixes (e.g. "ULL").
3500 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3501 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3502 used in assembly code, so it must not contain typecasts or
3503 integer size suffixes (e.g. "ULL").
3505 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3506 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3507 forced to a value that ensures that CCSR is not relocated.
3509 - Floppy Disk Support:
3510 CONFIG_SYS_FDC_DRIVE_NUMBER
3512 the default drive number (default value 0)
3514 CONFIG_SYS_ISA_IO_STRIDE
3516 defines the spacing between FDC chipset registers
3519 CONFIG_SYS_ISA_IO_OFFSET
3521 defines the offset of register from address. It
3522 depends on which part of the data bus is connected to
3523 the FDC chipset. (default value 0)
3525 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3526 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3529 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3530 fdc_hw_init() is called at the beginning of the FDC
3531 setup. fdc_hw_init() must be provided by the board
3532 source code. It is used to make hardware-dependent
3536 Most IDE controllers were designed to be connected with PCI
3537 interface. Only few of them were designed for AHB interface.
3538 When software is doing ATA command and data transfer to
3539 IDE devices through IDE-AHB controller, some additional
3540 registers accessing to these kind of IDE-AHB controller
3543 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3544 DO NOT CHANGE unless you know exactly what you're
3545 doing! (11-4) [MPC8xx systems only]
3547 - CONFIG_SYS_INIT_RAM_ADDR:
3549 Start address of memory area that can be used for
3550 initial data and stack; please note that this must be
3551 writable memory that is working WITHOUT special
3552 initialization, i. e. you CANNOT use normal RAM which
3553 will become available only after programming the
3554 memory controller and running certain initialization
3557 U-Boot uses the following memory types:
3558 - MPC8xx: IMMR (internal memory of the CPU)
3560 - CONFIG_SYS_GBL_DATA_OFFSET:
3562 Offset of the initial data structure in the memory
3563 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3564 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3565 data is located at the end of the available space
3566 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3567 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3568 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3569 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3572 On the MPC824X (or other systems that use the data
3573 cache for initial memory) the address chosen for
3574 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3575 point to an otherwise UNUSED address space between
3576 the top of RAM and the start of the PCI space.
3578 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3580 - CONFIG_SYS_OR_TIMING_SDRAM:
3583 - CONFIG_SYS_MAMR_PTA:
3584 periodic timer for refresh
3586 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3587 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3588 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3589 CONFIG_SYS_BR1_PRELIM:
3590 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3592 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3593 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3594 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3595 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3597 - CONFIG_PCI_ENUM_ONLY
3598 Only scan through and get the devices on the buses.
3599 Don't do any setup work, presumably because someone or
3600 something has already done it, and we don't need to do it
3601 a second time. Useful for platforms that are pre-booted
3602 by coreboot or similar.
3604 - CONFIG_PCI_INDIRECT_BRIDGE:
3605 Enable support for indirect PCI bridges.
3608 Chip has SRIO or not
3611 Board has SRIO 1 port available
3614 Board has SRIO 2 port available
3616 - CONFIG_SRIO_PCIE_BOOT_MASTER
3617 Board can support master function for Boot from SRIO and PCIE
3619 - CONFIG_SYS_SRIOn_MEM_VIRT:
3620 Virtual Address of SRIO port 'n' memory region
3622 - CONFIG_SYS_SRIOn_MEM_PHYS:
3623 Physical Address of SRIO port 'n' memory region
3625 - CONFIG_SYS_SRIOn_MEM_SIZE:
3626 Size of SRIO port 'n' memory region
3628 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3629 Defined to tell the NAND controller that the NAND chip is using
3631 Not all NAND drivers use this symbol.
3632 Example of drivers that use it:
3633 - drivers/mtd/nand/ndfc.c
3634 - drivers/mtd/nand/mxc_nand.c
3636 - CONFIG_SYS_NDFC_EBC0_CFG
3637 Sets the EBC0_CFG register for the NDFC. If not defined
3638 a default value will be used.
3641 Get DDR timing information from an I2C EEPROM. Common
3642 with pluggable memory modules such as SODIMMs
3645 I2C address of the SPD EEPROM
3647 - CONFIG_SYS_SPD_BUS_NUM
3648 If SPD EEPROM is on an I2C bus other than the first
3649 one, specify here. Note that the value must resolve
3650 to something your driver can deal with.
3652 - CONFIG_SYS_DDR_RAW_TIMING
3653 Get DDR timing information from other than SPD. Common with
3654 soldered DDR chips onboard without SPD. DDR raw timing
3655 parameters are extracted from datasheet and hard-coded into
3656 header files or board specific files.
3658 - CONFIG_FSL_DDR_INTERACTIVE
3659 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3661 - CONFIG_FSL_DDR_SYNC_REFRESH
3662 Enable sync of refresh for multiple controllers.
3664 - CONFIG_FSL_DDR_BIST
3665 Enable built-in memory test for Freescale DDR controllers.
3667 - CONFIG_SYS_83XX_DDR_USES_CS0
3668 Only for 83xx systems. If specified, then DDR should
3669 be configured using CS0 and CS1 instead of CS2 and CS3.
3672 Enable RMII mode for all FECs.
3673 Note that this is a global option, we can't
3674 have one FEC in standard MII mode and another in RMII mode.
3676 - CONFIG_CRC32_VERIFY
3677 Add a verify option to the crc32 command.
3680 => crc32 -v <address> <count> <crc32>
3682 Where address/count indicate a memory area
3683 and crc32 is the correct crc32 which the
3687 Add the "loopw" memory command. This only takes effect if
3688 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3691 Add the "mdc" and "mwc" memory commands. These are cyclic
3696 This command will print 4 bytes (10,11,12,13) each 500 ms.
3698 => mwc.l 100 12345678 10
3699 This command will write 12345678 to address 100 all 10 ms.
3701 This only takes effect if the memory commands are activated
3702 globally (CONFIG_CMD_MEMORY).
3704 - CONFIG_SKIP_LOWLEVEL_INIT
3705 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3706 low level initializations (like setting up the memory
3707 controller) are omitted and/or U-Boot does not
3708 relocate itself into RAM.
3710 Normally this variable MUST NOT be defined. The only
3711 exception is when U-Boot is loaded (to RAM) by some
3712 other boot loader or by a debugger which performs
3713 these initializations itself.
3715 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3716 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3717 to be skipped. The normal CP15 init (such as enabling the
3718 instruction cache) is still performed.
3721 Modifies the behaviour of start.S when compiling a loader
3722 that is executed before the actual U-Boot. E.g. when
3723 compiling a NAND SPL.
3726 Modifies the behaviour of start.S when compiling a loader
3727 that is executed after the SPL and before the actual U-Boot.
3728 It is loaded by the SPL.
3730 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3731 Only for 85xx systems. If this variable is specified, the section
3732 .resetvec is not kept and the section .bootpg is placed in the
3733 previous 4k of the .text section.
3735 - CONFIG_ARCH_MAP_SYSMEM
3736 Generally U-Boot (and in particular the md command) uses
3737 effective address. It is therefore not necessary to regard
3738 U-Boot address as virtual addresses that need to be translated
3739 to physical addresses. However, sandbox requires this, since
3740 it maintains its own little RAM buffer which contains all
3741 addressable memory. This option causes some memory accesses
3742 to be mapped through map_sysmem() / unmap_sysmem().
3744 - CONFIG_X86_RESET_VECTOR
3745 If defined, the x86 reset vector code is included. This is not
3746 needed when U-Boot is running from Coreboot.
3748 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3749 Enables the RTC32K OSC on AM33xx based plattforms
3751 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3752 Option to disable subpage write in NAND driver
3753 driver that uses this:
3754 drivers/mtd/nand/davinci_nand.c
3756 Freescale QE/FMAN Firmware Support:
3757 -----------------------------------
3759 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3760 loading of "firmware", which is encoded in the QE firmware binary format.
3761 This firmware often needs to be loaded during U-Boot booting, so macros
3762 are used to identify the storage device (NOR flash, SPI, etc) and the address
3765 - CONFIG_SYS_FMAN_FW_ADDR
3766 The address in the storage device where the FMAN microcode is located. The
3767 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3770 - CONFIG_SYS_QE_FW_ADDR
3771 The address in the storage device where the QE microcode is located. The
3772 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3775 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3776 The maximum possible size of the firmware. The firmware binary format
3777 has a field that specifies the actual size of the firmware, but it
3778 might not be possible to read any part of the firmware unless some
3779 local storage is allocated to hold the entire firmware first.
3781 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3782 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3783 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3784 virtual address in NOR flash.
3786 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3787 Specifies that QE/FMAN firmware is located in NAND flash.
3788 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3790 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3791 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3792 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3794 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3795 Specifies that QE/FMAN firmware is located in the remote (master)
3796 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3797 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3798 window->master inbound window->master LAW->the ucode address in
3799 master's memory space.
3801 Freescale Layerscape Management Complex Firmware Support:
3802 ---------------------------------------------------------
3803 The Freescale Layerscape Management Complex (MC) supports the loading of
3805 This firmware often needs to be loaded during U-Boot booting, so macros
3806 are used to identify the storage device (NOR flash, SPI, etc) and the address
3809 - CONFIG_FSL_MC_ENET
3810 Enable the MC driver for Layerscape SoCs.
3812 Freescale Layerscape Debug Server Support:
3813 -------------------------------------------
3814 The Freescale Layerscape Debug Server Support supports the loading of
3815 "Debug Server firmware" and triggering SP boot-rom.
3816 This firmware often needs to be loaded during U-Boot booting.
3818 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3819 Define alignment of reserved memory MC requires
3824 In order to achieve reproducible builds, timestamps used in the U-Boot build
3825 process have to be set to a fixed value.
3827 This is done using the SOURCE_DATE_EPOCH environment variable.
3828 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3829 option for U-Boot or an environment variable in U-Boot.
3831 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3833 Building the Software:
3834 ======================
3836 Building U-Boot has been tested in several native build environments
3837 and in many different cross environments. Of course we cannot support
3838 all possibly existing versions of cross development tools in all
3839 (potentially obsolete) versions. In case of tool chain problems we
3840 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3841 which is extensively used to build and test U-Boot.
3843 If you are not using a native environment, it is assumed that you
3844 have GNU cross compiling tools available in your path. In this case,
3845 you must set the environment variable CROSS_COMPILE in your shell.
3846 Note that no changes to the Makefile or any other source files are
3847 necessary. For example using the ELDK on a 4xx CPU, please enter:
3849 $ CROSS_COMPILE=ppc_4xx-
3850 $ export CROSS_COMPILE
3852 Note: If you wish to generate Windows versions of the utilities in
3853 the tools directory you can use the MinGW toolchain
3854 (http://www.mingw.org). Set your HOST tools to the MinGW
3855 toolchain and execute 'make tools'. For example:
3857 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3859 Binaries such as tools/mkimage.exe will be created which can
3860 be executed on computers running Windows.
3862 U-Boot is intended to be simple to build. After installing the
3863 sources you must configure U-Boot for one specific board type. This
3868 where "NAME_defconfig" is the name of one of the existing configu-
3869 rations; see boards.cfg for supported names.
3871 Note: for some board special configuration names may exist; check if
3872 additional information is available from the board vendor; for
3873 instance, the TQM823L systems are available without (standard)
3874 or with LCD support. You can select such additional "features"
3875 when choosing the configuration, i. e.
3877 make TQM823L_defconfig
3878 - will configure for a plain TQM823L, i. e. no LCD support
3880 make TQM823L_LCD_defconfig
3881 - will configure for a TQM823L with U-Boot console on LCD
3886 Finally, type "make all", and you should get some working U-Boot
3887 images ready for download to / installation on your system:
3889 - "u-boot.bin" is a raw binary image
3890 - "u-boot" is an image in ELF binary format
3891 - "u-boot.srec" is in Motorola S-Record format
3893 By default the build is performed locally and the objects are saved
3894 in the source directory. One of the two methods can be used to change
3895 this behavior and build U-Boot to some external directory:
3897 1. Add O= to the make command line invocations:
3899 make O=/tmp/build distclean
3900 make O=/tmp/build NAME_defconfig
3901 make O=/tmp/build all
3903 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3905 export KBUILD_OUTPUT=/tmp/build
3910 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3914 Please be aware that the Makefiles assume you are using GNU make, so
3915 for instance on NetBSD you might need to use "gmake" instead of
3919 If the system board that you have is not listed, then you will need
3920 to port U-Boot to your hardware platform. To do this, follow these
3923 1. Create a new directory to hold your board specific code. Add any
3924 files you need. In your board directory, you will need at least
3925 the "Makefile" and a "<board>.c".
3926 2. Create a new configuration file "include/configs/<board>.h" for
3928 3. If you're porting U-Boot to a new CPU, then also create a new
3929 directory to hold your CPU specific code. Add any files you need.
3930 4. Run "make <board>_defconfig" with your new name.
3931 5. Type "make", and you should get a working "u-boot.srec" file
3932 to be installed on your target system.
3933 6. Debug and solve any problems that might arise.
3934 [Of course, this last step is much harder than it sounds.]
3937 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3938 ==============================================================
3940 If you have modified U-Boot sources (for instance added a new board
3941 or support for new devices, a new CPU, etc.) you are expected to
3942 provide feedback to the other developers. The feedback normally takes
3943 the form of a "patch", i. e. a context diff against a certain (latest
3944 official or latest in the git repository) version of U-Boot sources.
3946 But before you submit such a patch, please verify that your modifi-
3947 cation did not break existing code. At least make sure that *ALL* of
3948 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3949 just run the buildman script (tools/buildman/buildman), which will
3950 configure and build U-Boot for ALL supported system. Be warned, this
3951 will take a while. Please see the buildman README, or run 'buildman -H'
3955 See also "U-Boot Porting Guide" below.
3958 Monitor Commands - Overview:
3959 ============================
3961 go - start application at address 'addr'
3962 run - run commands in an environment variable
3963 bootm - boot application image from memory
3964 bootp - boot image via network using BootP/TFTP protocol
3965 bootz - boot zImage from memory
3966 tftpboot- boot image via network using TFTP protocol
3967 and env variables "ipaddr" and "serverip"
3968 (and eventually "gatewayip")
3969 tftpput - upload a file via network using TFTP protocol
3970 rarpboot- boot image via network using RARP/TFTP protocol
3971 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3972 loads - load S-Record file over serial line
3973 loadb - load binary file over serial line (kermit mode)
3975 mm - memory modify (auto-incrementing)
3976 nm - memory modify (constant address)
3977 mw - memory write (fill)
3979 cmp - memory compare
3980 crc32 - checksum calculation
3981 i2c - I2C sub-system
3982 sspi - SPI utility commands
3983 base - print or set address offset
3984 printenv- print environment variables
3985 setenv - set environment variables
3986 saveenv - save environment variables to persistent storage
3987 protect - enable or disable FLASH write protection
3988 erase - erase FLASH memory
3989 flinfo - print FLASH memory information
3990 nand - NAND memory operations (see doc/README.nand)
3991 bdinfo - print Board Info structure
3992 iminfo - print header information for application image
3993 coninfo - print console devices and informations
3994 ide - IDE sub-system
3995 loop - infinite loop on address range
3996 loopw - infinite write loop on address range
3997 mtest - simple RAM test
3998 icache - enable or disable instruction cache
3999 dcache - enable or disable data cache
4000 reset - Perform RESET of the CPU
4001 echo - echo args to console
4002 version - print monitor version
4003 help - print online help
4004 ? - alias for 'help'
4007 Monitor Commands - Detailed Description:
4008 ========================================
4012 For now: just type "help <command>".
4015 Environment Variables:
4016 ======================
4018 U-Boot supports user configuration using Environment Variables which
4019 can be made persistent by saving to Flash memory.
4021 Environment Variables are set using "setenv", printed using
4022 "printenv", and saved to Flash using "saveenv". Using "setenv"
4023 without a value can be used to delete a variable from the
4024 environment. As long as you don't save the environment you are
4025 working with an in-memory copy. In case the Flash area containing the
4026 environment is erased by accident, a default environment is provided.
4028 Some configuration options can be set using Environment Variables.
4030 List of environment variables (most likely not complete):
4032 baudrate - see CONFIG_BAUDRATE
4034 bootdelay - see CONFIG_BOOTDELAY
4036 bootcmd - see CONFIG_BOOTCOMMAND
4038 bootargs - Boot arguments when booting an RTOS image
4040 bootfile - Name of the image to load with TFTP
4042 bootm_low - Memory range available for image processing in the bootm
4043 command can be restricted. This variable is given as
4044 a hexadecimal number and defines lowest address allowed
4045 for use by the bootm command. See also "bootm_size"
4046 environment variable. Address defined by "bootm_low" is
4047 also the base of the initial memory mapping for the Linux
4048 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4051 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4052 This variable is given as a hexadecimal number and it
4053 defines the size of the memory region starting at base
4054 address bootm_low that is accessible by the Linux kernel
4055 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4056 as the default value if it is defined, and bootm_size is
4059 bootm_size - Memory range available for image processing in the bootm
4060 command can be restricted. This variable is given as
4061 a hexadecimal number and defines the size of the region
4062 allowed for use by the bootm command. See also "bootm_low"
4063 environment variable.
4065 updatefile - Location of the software update file on a TFTP server, used
4066 by the automatic software update feature. Please refer to
4067 documentation in doc/README.update for more details.
4069 autoload - if set to "no" (any string beginning with 'n'),
4070 "bootp" will just load perform a lookup of the
4071 configuration from the BOOTP server, but not try to
4072 load any image using TFTP
4074 autostart - if set to "yes", an image loaded using the "bootp",
4075 "rarpboot", "tftpboot" or "diskboot" commands will
4076 be automatically started (by internally calling
4079 If set to "no", a standalone image passed to the
4080 "bootm" command will be copied to the load address
4081 (and eventually uncompressed), but NOT be started.
4082 This can be used to load and uncompress arbitrary
4085 fdt_high - if set this restricts the maximum address that the
4086 flattened device tree will be copied into upon boot.
4087 For example, if you have a system with 1 GB memory
4088 at physical address 0x10000000, while Linux kernel
4089 only recognizes the first 704 MB as low memory, you
4090 may need to set fdt_high as 0x3C000000 to have the
4091 device tree blob be copied to the maximum address
4092 of the 704 MB low memory, so that Linux kernel can
4093 access it during the boot procedure.
4095 If this is set to the special value 0xFFFFFFFF then
4096 the fdt will not be copied at all on boot. For this
4097 to work it must reside in writable memory, have
4098 sufficient padding on the end of it for u-boot to
4099 add the information it needs into it, and the memory
4100 must be accessible by the kernel.
4102 fdtcontroladdr- if set this is the address of the control flattened
4103 device tree used by U-Boot when CONFIG_OF_CONTROL is
4106 i2cfast - (PPC405GP|PPC405EP only)
4107 if set to 'y' configures Linux I2C driver for fast
4108 mode (400kHZ). This environment variable is used in
4109 initialization code. So, for changes to be effective
4110 it must be saved and board must be reset.
4112 initrd_high - restrict positioning of initrd images:
4113 If this variable is not set, initrd images will be
4114 copied to the highest possible address in RAM; this
4115 is usually what you want since it allows for
4116 maximum initrd size. If for some reason you want to
4117 make sure that the initrd image is loaded below the
4118 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4119 variable to a value of "no" or "off" or "0".
4120 Alternatively, you can set it to a maximum upper
4121 address to use (U-Boot will still check that it
4122 does not overwrite the U-Boot stack and data).
4124 For instance, when you have a system with 16 MB
4125 RAM, and want to reserve 4 MB from use by Linux,
4126 you can do this by adding "mem=12M" to the value of
4127 the "bootargs" variable. However, now you must make
4128 sure that the initrd image is placed in the first
4129 12 MB as well - this can be done with
4131 setenv initrd_high 00c00000
4133 If you set initrd_high to 0xFFFFFFFF, this is an
4134 indication to U-Boot that all addresses are legal
4135 for the Linux kernel, including addresses in flash
4136 memory. In this case U-Boot will NOT COPY the
4137 ramdisk at all. This may be useful to reduce the
4138 boot time on your system, but requires that this
4139 feature is supported by your Linux kernel.
4141 ipaddr - IP address; needed for tftpboot command
4143 loadaddr - Default load address for commands like "bootp",
4144 "rarpboot", "tftpboot", "loadb" or "diskboot"
4146 loads_echo - see CONFIG_LOADS_ECHO
4148 serverip - TFTP server IP address; needed for tftpboot command
4150 bootretry - see CONFIG_BOOT_RETRY_TIME
4152 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4154 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4156 ethprime - controls which interface is used first.
4158 ethact - controls which interface is currently active.
4159 For example you can do the following
4161 => setenv ethact FEC
4162 => ping 192.168.0.1 # traffic sent on FEC
4163 => setenv ethact SCC
4164 => ping 10.0.0.1 # traffic sent on SCC
4166 ethrotate - When set to "no" U-Boot does not go through all
4167 available network interfaces.
4168 It just stays at the currently selected interface.
4170 netretry - When set to "no" each network operation will
4171 either succeed or fail without retrying.
4172 When set to "once" the network operation will
4173 fail when all the available network interfaces
4174 are tried once without success.
4175 Useful on scripts which control the retry operation
4178 npe_ucode - set load address for the NPE microcode
4180 silent_linux - If set then Linux will be told to boot silently, by
4181 changing the console to be empty. If "yes" it will be
4182 made silent. If "no" it will not be made silent. If
4183 unset, then it will be made silent if the U-Boot console
4186 tftpsrcp - If this is set, the value is used for TFTP's
4189 tftpdstp - If this is set, the value is used for TFTP's UDP
4190 destination port instead of the Well Know Port 69.
4192 tftpblocksize - Block size to use for TFTP transfers; if not set,
4193 we use the TFTP server's default block size
4195 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4196 seconds, minimum value is 1000 = 1 second). Defines
4197 when a packet is considered to be lost so it has to
4198 be retransmitted. The default is 5000 = 5 seconds.
4199 Lowering this value may make downloads succeed
4200 faster in networks with high packet loss rates or
4201 with unreliable TFTP servers.
4203 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4204 unit, minimum value = 0). Defines how many timeouts
4205 can happen during a single file transfer before that
4206 transfer is aborted. The default is 10, and 0 means
4207 'no timeouts allowed'. Increasing this value may help
4208 downloads succeed with high packet loss rates, or with
4209 unreliable TFTP servers or client hardware.
4211 vlan - When set to a value < 4095 the traffic over
4212 Ethernet is encapsulated/received over 802.1q
4215 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4216 Unsigned value, in milliseconds. If not set, the period will
4217 be either the default (28000), or a value based on
4218 CONFIG_NET_RETRY_COUNT, if defined. This value has
4219 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4221 The following image location variables contain the location of images
4222 used in booting. The "Image" column gives the role of the image and is
4223 not an environment variable name. The other columns are environment
4224 variable names. "File Name" gives the name of the file on a TFTP
4225 server, "RAM Address" gives the location in RAM the image will be
4226 loaded to, and "Flash Location" gives the image's address in NOR
4227 flash or offset in NAND flash.
4229 *Note* - these variables don't have to be defined for all boards, some
4230 boards currently use other variables for these purposes, and some
4231 boards use these variables for other purposes.
4233 Image File Name RAM Address Flash Location
4234 ----- --------- ----------- --------------
4235 u-boot u-boot u-boot_addr_r u-boot_addr
4236 Linux kernel bootfile kernel_addr_r kernel_addr
4237 device tree blob fdtfile fdt_addr_r fdt_addr
4238 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4240 The following environment variables may be used and automatically
4241 updated by the network boot commands ("bootp" and "rarpboot"),
4242 depending the information provided by your boot server:
4244 bootfile - see above
4245 dnsip - IP address of your Domain Name Server
4246 dnsip2 - IP address of your secondary Domain Name Server
4247 gatewayip - IP address of the Gateway (Router) to use
4248 hostname - Target hostname
4250 netmask - Subnet Mask
4251 rootpath - Pathname of the root filesystem on the NFS server
4252 serverip - see above
4255 There are two special Environment Variables:
4257 serial# - contains hardware identification information such
4258 as type string and/or serial number
4259 ethaddr - Ethernet address
4261 These variables can be set only once (usually during manufacturing of
4262 the board). U-Boot refuses to delete or overwrite these variables
4263 once they have been set once.
4266 Further special Environment Variables:
4268 ver - Contains the U-Boot version string as printed
4269 with the "version" command. This variable is
4270 readonly (see CONFIG_VERSION_VARIABLE).
4273 Please note that changes to some configuration parameters may take
4274 only effect after the next boot (yes, that's just like Windoze :-).
4277 Callback functions for environment variables:
4278 ---------------------------------------------
4280 For some environment variables, the behavior of u-boot needs to change
4281 when their values are changed. This functionality allows functions to
4282 be associated with arbitrary variables. On creation, overwrite, or
4283 deletion, the callback will provide the opportunity for some side
4284 effect to happen or for the change to be rejected.
4286 The callbacks are named and associated with a function using the
4287 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4289 These callbacks are associated with variables in one of two ways. The
4290 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4291 in the board configuration to a string that defines a list of
4292 associations. The list must be in the following format:
4294 entry = variable_name[:callback_name]
4297 If the callback name is not specified, then the callback is deleted.
4298 Spaces are also allowed anywhere in the list.
4300 Callbacks can also be associated by defining the ".callbacks" variable
4301 with the same list format above. Any association in ".callbacks" will
4302 override any association in the static list. You can define
4303 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4304 ".callbacks" environment variable in the default or embedded environment.
4306 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4307 regular expression. This allows multiple variables to be connected to
4308 the same callback without explicitly listing them all out.
4311 Command Line Parsing:
4312 =====================
4314 There are two different command line parsers available with U-Boot:
4315 the old "simple" one, and the much more powerful "hush" shell:
4317 Old, simple command line parser:
4318 --------------------------------
4320 - supports environment variables (through setenv / saveenv commands)
4321 - several commands on one line, separated by ';'
4322 - variable substitution using "... ${name} ..." syntax
4323 - special characters ('$', ';') can be escaped by prefixing with '\',
4325 setenv bootcmd bootm \${address}
4326 - You can also escape text by enclosing in single apostrophes, for example:
4327 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4332 - similar to Bourne shell, with control structures like
4333 if...then...else...fi, for...do...done; while...do...done,
4334 until...do...done, ...
4335 - supports environment ("global") variables (through setenv / saveenv
4336 commands) and local shell variables (through standard shell syntax
4337 "name=value"); only environment variables can be used with "run"
4343 (1) If a command line (or an environment variable executed by a "run"
4344 command) contains several commands separated by semicolon, and
4345 one of these commands fails, then the remaining commands will be
4348 (2) If you execute several variables with one call to run (i. e.
4349 calling run with a list of variables as arguments), any failing
4350 command will cause "run" to terminate, i. e. the remaining
4351 variables are not executed.
4353 Note for Redundant Ethernet Interfaces:
4354 =======================================
4356 Some boards come with redundant Ethernet interfaces; U-Boot supports
4357 such configurations and is capable of automatic selection of a
4358 "working" interface when needed. MAC assignment works as follows:
4360 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4361 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4362 "eth1addr" (=>eth1), "eth2addr", ...
4364 If the network interface stores some valid MAC address (for instance
4365 in SROM), this is used as default address if there is NO correspon-
4366 ding setting in the environment; if the corresponding environment
4367 variable is set, this overrides the settings in the card; that means:
4369 o If the SROM has a valid MAC address, and there is no address in the
4370 environment, the SROM's address is used.
4372 o If there is no valid address in the SROM, and a definition in the
4373 environment exists, then the value from the environment variable is
4376 o If both the SROM and the environment contain a MAC address, and
4377 both addresses are the same, this MAC address is used.
4379 o If both the SROM and the environment contain a MAC address, and the
4380 addresses differ, the value from the environment is used and a
4383 o If neither SROM nor the environment contain a MAC address, an error
4384 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4385 a random, locally-assigned MAC is used.
4387 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4388 will be programmed into hardware as part of the initialization process. This
4389 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4390 The naming convention is as follows:
4391 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4396 U-Boot is capable of booting (and performing other auxiliary operations on)
4397 images in two formats:
4399 New uImage format (FIT)
4400 -----------------------
4402 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4403 to Flattened Device Tree). It allows the use of images with multiple
4404 components (several kernels, ramdisks, etc.), with contents protected by
4405 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4411 Old image format is based on binary files which can be basically anything,
4412 preceded by a special header; see the definitions in include/image.h for
4413 details; basically, the header defines the following image properties:
4415 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4416 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4417 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4418 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4420 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4421 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4422 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4423 * Compression Type (uncompressed, gzip, bzip2)
4429 The header is marked by a special Magic Number, and both the header
4430 and the data portions of the image are secured against corruption by
4437 Although U-Boot should support any OS or standalone application
4438 easily, the main focus has always been on Linux during the design of
4441 U-Boot includes many features that so far have been part of some
4442 special "boot loader" code within the Linux kernel. Also, any
4443 "initrd" images to be used are no longer part of one big Linux image;
4444 instead, kernel and "initrd" are separate images. This implementation
4445 serves several purposes:
4447 - the same features can be used for other OS or standalone
4448 applications (for instance: using compressed images to reduce the
4449 Flash memory footprint)
4451 - it becomes much easier to port new Linux kernel versions because
4452 lots of low-level, hardware dependent stuff are done by U-Boot
4454 - the same Linux kernel image can now be used with different "initrd"
4455 images; of course this also means that different kernel images can
4456 be run with the same "initrd". This makes testing easier (you don't
4457 have to build a new "zImage.initrd" Linux image when you just
4458 change a file in your "initrd"). Also, a field-upgrade of the
4459 software is easier now.
4465 Porting Linux to U-Boot based systems:
4466 ---------------------------------------
4468 U-Boot cannot save you from doing all the necessary modifications to
4469 configure the Linux device drivers for use with your target hardware
4470 (no, we don't intend to provide a full virtual machine interface to
4473 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4475 Just make sure your machine specific header file (for instance
4476 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4477 Information structure as we define in include/asm-<arch>/u-boot.h,
4478 and make sure that your definition of IMAP_ADDR uses the same value
4479 as your U-Boot configuration in CONFIG_SYS_IMMR.
4481 Note that U-Boot now has a driver model, a unified model for drivers.
4482 If you are adding a new driver, plumb it into driver model. If there
4483 is no uclass available, you are encouraged to create one. See
4487 Configuring the Linux kernel:
4488 -----------------------------
4490 No specific requirements for U-Boot. Make sure you have some root
4491 device (initial ramdisk, NFS) for your target system.
4494 Building a Linux Image:
4495 -----------------------
4497 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4498 not used. If you use recent kernel source, a new build target
4499 "uImage" will exist which automatically builds an image usable by
4500 U-Boot. Most older kernels also have support for a "pImage" target,
4501 which was introduced for our predecessor project PPCBoot and uses a
4502 100% compatible format.
4506 make TQM850L_defconfig
4511 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4512 encapsulate a compressed Linux kernel image with header information,
4513 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4515 * build a standard "vmlinux" kernel image (in ELF binary format):
4517 * convert the kernel into a raw binary image:
4519 ${CROSS_COMPILE}-objcopy -O binary \
4520 -R .note -R .comment \
4521 -S vmlinux linux.bin
4523 * compress the binary image:
4527 * package compressed binary image for U-Boot:
4529 mkimage -A ppc -O linux -T kernel -C gzip \
4530 -a 0 -e 0 -n "Linux Kernel Image" \
4531 -d linux.bin.gz uImage
4534 The "mkimage" tool can also be used to create ramdisk images for use
4535 with U-Boot, either separated from the Linux kernel image, or
4536 combined into one file. "mkimage" encapsulates the images with a 64
4537 byte header containing information about target architecture,
4538 operating system, image type, compression method, entry points, time
4539 stamp, CRC32 checksums, etc.
4541 "mkimage" can be called in two ways: to verify existing images and
4542 print the header information, or to build new images.
4544 In the first form (with "-l" option) mkimage lists the information
4545 contained in the header of an existing U-Boot image; this includes
4546 checksum verification:
4548 tools/mkimage -l image
4549 -l ==> list image header information
4551 The second form (with "-d" option) is used to build a U-Boot image
4552 from a "data file" which is used as image payload:
4554 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4555 -n name -d data_file image
4556 -A ==> set architecture to 'arch'
4557 -O ==> set operating system to 'os'
4558 -T ==> set image type to 'type'
4559 -C ==> set compression type 'comp'
4560 -a ==> set load address to 'addr' (hex)
4561 -e ==> set entry point to 'ep' (hex)
4562 -n ==> set image name to 'name'
4563 -d ==> use image data from 'datafile'
4565 Right now, all Linux kernels for PowerPC systems use the same load
4566 address (0x00000000), but the entry point address depends on the
4569 - 2.2.x kernels have the entry point at 0x0000000C,
4570 - 2.3.x and later kernels have the entry point at 0x00000000.
4572 So a typical call to build a U-Boot image would read:
4574 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4575 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4576 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4577 > examples/uImage.TQM850L
4578 Image Name: 2.4.4 kernel for TQM850L
4579 Created: Wed Jul 19 02:34:59 2000
4580 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4581 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4582 Load Address: 0x00000000
4583 Entry Point: 0x00000000
4585 To verify the contents of the image (or check for corruption):
4587 -> tools/mkimage -l examples/uImage.TQM850L
4588 Image Name: 2.4.4 kernel for TQM850L
4589 Created: Wed Jul 19 02:34:59 2000
4590 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4591 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4592 Load Address: 0x00000000
4593 Entry Point: 0x00000000
4595 NOTE: for embedded systems where boot time is critical you can trade
4596 speed for memory and install an UNCOMPRESSED image instead: this
4597 needs more space in Flash, but boots much faster since it does not
4598 need to be uncompressed:
4600 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4601 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4602 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4603 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4604 > examples/uImage.TQM850L-uncompressed
4605 Image Name: 2.4.4 kernel for TQM850L
4606 Created: Wed Jul 19 02:34:59 2000
4607 Image Type: PowerPC Linux Kernel Image (uncompressed)
4608 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4609 Load Address: 0x00000000
4610 Entry Point: 0x00000000
4613 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4614 when your kernel is intended to use an initial ramdisk:
4616 -> tools/mkimage -n 'Simple Ramdisk Image' \
4617 > -A ppc -O linux -T ramdisk -C gzip \
4618 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4619 Image Name: Simple Ramdisk Image
4620 Created: Wed Jan 12 14:01:50 2000
4621 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4622 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4623 Load Address: 0x00000000
4624 Entry Point: 0x00000000
4626 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4627 option performs the converse operation of the mkimage's second form (the "-d"
4628 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4631 tools/dumpimage -i image -T type -p position data_file
4632 -i ==> extract from the 'image' a specific 'data_file'
4633 -T ==> set image type to 'type'
4634 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4637 Installing a Linux Image:
4638 -------------------------
4640 To downloading a U-Boot image over the serial (console) interface,
4641 you must convert the image to S-Record format:
4643 objcopy -I binary -O srec examples/image examples/image.srec
4645 The 'objcopy' does not understand the information in the U-Boot
4646 image header, so the resulting S-Record file will be relative to
4647 address 0x00000000. To load it to a given address, you need to
4648 specify the target address as 'offset' parameter with the 'loads'
4651 Example: install the image to address 0x40100000 (which on the
4652 TQM8xxL is in the first Flash bank):
4654 => erase 40100000 401FFFFF
4660 ## Ready for S-Record download ...
4661 ~>examples/image.srec
4662 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4664 15989 15990 15991 15992
4665 [file transfer complete]
4667 ## Start Addr = 0x00000000
4670 You can check the success of the download using the 'iminfo' command;
4671 this includes a checksum verification so you can be sure no data
4672 corruption happened:
4676 ## Checking Image at 40100000 ...
4677 Image Name: 2.2.13 for initrd on TQM850L
4678 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4679 Data Size: 335725 Bytes = 327 kB = 0 MB
4680 Load Address: 00000000
4681 Entry Point: 0000000c
4682 Verifying Checksum ... OK
4688 The "bootm" command is used to boot an application that is stored in
4689 memory (RAM or Flash). In case of a Linux kernel image, the contents
4690 of the "bootargs" environment variable is passed to the kernel as
4691 parameters. You can check and modify this variable using the
4692 "printenv" and "setenv" commands:
4695 => printenv bootargs
4696 bootargs=root=/dev/ram
4698 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4700 => printenv bootargs
4701 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4704 ## Booting Linux kernel at 40020000 ...
4705 Image Name: 2.2.13 for NFS on TQM850L
4706 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4707 Data Size: 381681 Bytes = 372 kB = 0 MB
4708 Load Address: 00000000
4709 Entry Point: 0000000c
4710 Verifying Checksum ... OK
4711 Uncompressing Kernel Image ... OK
4712 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
4713 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4714 time_init: decrementer frequency = 187500000/60
4715 Calibrating delay loop... 49.77 BogoMIPS
4716 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4719 If you want to boot a Linux kernel with initial RAM disk, you pass
4720 the memory addresses of both the kernel and the initrd image (PPBCOOT
4721 format!) to the "bootm" command:
4723 => imi 40100000 40200000
4725 ## Checking Image at 40100000 ...
4726 Image Name: 2.2.13 for initrd on TQM850L
4727 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4728 Data Size: 335725 Bytes = 327 kB = 0 MB
4729 Load Address: 00000000
4730 Entry Point: 0000000c
4731 Verifying Checksum ... OK
4733 ## Checking Image at 40200000 ...
4734 Image Name: Simple Ramdisk Image
4735 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4736 Data Size: 566530 Bytes = 553 kB = 0 MB
4737 Load Address: 00000000
4738 Entry Point: 00000000
4739 Verifying Checksum ... OK
4741 => bootm 40100000 40200000
4742 ## Booting Linux kernel at 40100000 ...
4743 Image Name: 2.2.13 for initrd on TQM850L
4744 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4745 Data Size: 335725 Bytes = 327 kB = 0 MB
4746 Load Address: 00000000
4747 Entry Point: 0000000c
4748 Verifying Checksum ... OK
4749 Uncompressing Kernel Image ... OK
4750 ## Loading RAMDisk Image at 40200000 ...
4751 Image Name: Simple Ramdisk Image
4752 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4753 Data Size: 566530 Bytes = 553 kB = 0 MB
4754 Load Address: 00000000
4755 Entry Point: 00000000
4756 Verifying Checksum ... OK
4757 Loading Ramdisk ... OK
4758 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
4759 Boot arguments: root=/dev/ram
4760 time_init: decrementer frequency = 187500000/60
4761 Calibrating delay loop... 49.77 BogoMIPS
4763 RAMDISK: Compressed image found at block 0
4764 VFS: Mounted root (ext2 filesystem).
4768 Boot Linux and pass a flat device tree:
4771 First, U-Boot must be compiled with the appropriate defines. See the section
4772 titled "Linux Kernel Interface" above for a more in depth explanation. The
4773 following is an example of how to start a kernel and pass an updated
4779 oft=oftrees/mpc8540ads.dtb
4780 => tftp $oftaddr $oft
4781 Speed: 1000, full duplex
4783 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4784 Filename 'oftrees/mpc8540ads.dtb'.
4785 Load address: 0x300000
4788 Bytes transferred = 4106 (100a hex)
4789 => tftp $loadaddr $bootfile
4790 Speed: 1000, full duplex
4792 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4794 Load address: 0x200000
4795 Loading:############
4797 Bytes transferred = 1029407 (fb51f hex)
4802 => bootm $loadaddr - $oftaddr
4803 ## Booting image at 00200000 ...
4804 Image Name: Linux-2.6.17-dirty
4805 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4806 Data Size: 1029343 Bytes = 1005.2 kB
4807 Load Address: 00000000
4808 Entry Point: 00000000
4809 Verifying Checksum ... OK
4810 Uncompressing Kernel Image ... OK
4811 Booting using flat device tree at 0x300000
4812 Using MPC85xx ADS machine description
4813 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4817 More About U-Boot Image Types:
4818 ------------------------------
4820 U-Boot supports the following image types:
4822 "Standalone Programs" are directly runnable in the environment
4823 provided by U-Boot; it is expected that (if they behave
4824 well) you can continue to work in U-Boot after return from
4825 the Standalone Program.
4826 "OS Kernel Images" are usually images of some Embedded OS which
4827 will take over control completely. Usually these programs
4828 will install their own set of exception handlers, device
4829 drivers, set up the MMU, etc. - this means, that you cannot
4830 expect to re-enter U-Boot except by resetting the CPU.
4831 "RAMDisk Images" are more or less just data blocks, and their
4832 parameters (address, size) are passed to an OS kernel that is
4834 "Multi-File Images" contain several images, typically an OS
4835 (Linux) kernel image and one or more data images like
4836 RAMDisks. This construct is useful for instance when you want
4837 to boot over the network using BOOTP etc., where the boot
4838 server provides just a single image file, but you want to get
4839 for instance an OS kernel and a RAMDisk image.
4841 "Multi-File Images" start with a list of image sizes, each
4842 image size (in bytes) specified by an "uint32_t" in network
4843 byte order. This list is terminated by an "(uint32_t)0".
4844 Immediately after the terminating 0 follow the images, one by
4845 one, all aligned on "uint32_t" boundaries (size rounded up to
4846 a multiple of 4 bytes).
4848 "Firmware Images" are binary images containing firmware (like
4849 U-Boot or FPGA images) which usually will be programmed to
4852 "Script files" are command sequences that will be executed by
4853 U-Boot's command interpreter; this feature is especially
4854 useful when you configure U-Boot to use a real shell (hush)
4855 as command interpreter.
4857 Booting the Linux zImage:
4858 -------------------------
4860 On some platforms, it's possible to boot Linux zImage. This is done
4861 using the "bootz" command. The syntax of "bootz" command is the same
4862 as the syntax of "bootm" command.
4864 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4865 kernel with raw initrd images. The syntax is slightly different, the
4866 address of the initrd must be augmented by it's size, in the following
4867 format: "<initrd addres>:<initrd size>".
4873 One of the features of U-Boot is that you can dynamically load and
4874 run "standalone" applications, which can use some resources of
4875 U-Boot like console I/O functions or interrupt services.
4877 Two simple examples are included with the sources:
4882 'examples/hello_world.c' contains a small "Hello World" Demo
4883 application; it is automatically compiled when you build U-Boot.
4884 It's configured to run at address 0x00040004, so you can play with it
4888 ## Ready for S-Record download ...
4889 ~>examples/hello_world.srec
4890 1 2 3 4 5 6 7 8 9 10 11 ...
4891 [file transfer complete]
4893 ## Start Addr = 0x00040004
4895 => go 40004 Hello World! This is a test.
4896 ## Starting application at 0x00040004 ...
4907 Hit any key to exit ...
4909 ## Application terminated, rc = 0x0
4911 Another example, which demonstrates how to register a CPM interrupt
4912 handler with the U-Boot code, can be found in 'examples/timer.c'.
4913 Here, a CPM timer is set up to generate an interrupt every second.
4914 The interrupt service routine is trivial, just printing a '.'
4915 character, but this is just a demo program. The application can be
4916 controlled by the following keys:
4918 ? - print current values og the CPM Timer registers
4919 b - enable interrupts and start timer
4920 e - stop timer and disable interrupts
4921 q - quit application
4924 ## Ready for S-Record download ...
4925 ~>examples/timer.srec
4926 1 2 3 4 5 6 7 8 9 10 11 ...
4927 [file transfer complete]
4929 ## Start Addr = 0x00040004
4932 ## Starting application at 0x00040004 ...
4935 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4938 [q, b, e, ?] Set interval 1000000 us
4941 [q, b, e, ?] ........
4942 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4945 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4948 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4951 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4953 [q, b, e, ?] ...Stopping timer
4955 [q, b, e, ?] ## Application terminated, rc = 0x0
4961 Over time, many people have reported problems when trying to use the
4962 "minicom" terminal emulation program for serial download. I (wd)
4963 consider minicom to be broken, and recommend not to use it. Under
4964 Unix, I recommend to use C-Kermit for general purpose use (and
4965 especially for kermit binary protocol download ("loadb" command), and
4966 use "cu" for S-Record download ("loads" command). See
4967 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4968 for help with kermit.
4971 Nevertheless, if you absolutely want to use it try adding this
4972 configuration to your "File transfer protocols" section:
4974 Name Program Name U/D FullScr IO-Red. Multi
4975 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4976 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4982 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4983 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4985 Building requires a cross environment; it is known to work on
4986 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4987 need gmake since the Makefiles are not compatible with BSD make).
4988 Note that the cross-powerpc package does not install include files;
4989 attempting to build U-Boot will fail because <machine/ansi.h> is
4990 missing. This file has to be installed and patched manually:
4992 # cd /usr/pkg/cross/powerpc-netbsd/include
4994 # ln -s powerpc machine
4995 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4996 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4998 Native builds *don't* work due to incompatibilities between native
4999 and U-Boot include files.
5001 Booting assumes that (the first part of) the image booted is a
5002 stage-2 loader which in turn loads and then invokes the kernel
5003 proper. Loader sources will eventually appear in the NetBSD source
5004 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5005 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5008 Implementation Internals:
5009 =========================
5011 The following is not intended to be a complete description of every
5012 implementation detail. However, it should help to understand the
5013 inner workings of U-Boot and make it easier to port it to custom
5017 Initial Stack, Global Data:
5018 ---------------------------
5020 The implementation of U-Boot is complicated by the fact that U-Boot
5021 starts running out of ROM (flash memory), usually without access to
5022 system RAM (because the memory controller is not initialized yet).
5023 This means that we don't have writable Data or BSS segments, and BSS
5024 is not initialized as zero. To be able to get a C environment working
5025 at all, we have to allocate at least a minimal stack. Implementation
5026 options for this are defined and restricted by the CPU used: Some CPU
5027 models provide on-chip memory (like the IMMR area on MPC8xx and
5028 MPC826x processors), on others (parts of) the data cache can be
5029 locked as (mis-) used as memory, etc.
5031 Chris Hallinan posted a good summary of these issues to the
5032 U-Boot mailing list:
5034 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5035 From: "Chris Hallinan" <clh@net1plus.com>
5036 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5039 Correct me if I'm wrong, folks, but the way I understand it
5040 is this: Using DCACHE as initial RAM for Stack, etc, does not
5041 require any physical RAM backing up the cache. The cleverness
5042 is that the cache is being used as a temporary supply of
5043 necessary storage before the SDRAM controller is setup. It's
5044 beyond the scope of this list to explain the details, but you
5045 can see how this works by studying the cache architecture and
5046 operation in the architecture and processor-specific manuals.
5048 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5049 is another option for the system designer to use as an
5050 initial stack/RAM area prior to SDRAM being available. Either
5051 option should work for you. Using CS 4 should be fine if your
5052 board designers haven't used it for something that would
5053 cause you grief during the initial boot! It is frequently not
5056 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5057 with your processor/board/system design. The default value
5058 you will find in any recent u-boot distribution in
5059 walnut.h should work for you. I'd set it to a value larger
5060 than your SDRAM module. If you have a 64MB SDRAM module, set
5061 it above 400_0000. Just make sure your board has no resources
5062 that are supposed to respond to that address! That code in
5063 start.S has been around a while and should work as is when
5064 you get the config right.
5069 It is essential to remember this, since it has some impact on the C
5070 code for the initialization procedures:
5072 * Initialized global data (data segment) is read-only. Do not attempt
5075 * Do not use any uninitialized global data (or implicitly initialized
5076 as zero data - BSS segment) at all - this is undefined, initiali-
5077 zation is performed later (when relocating to RAM).
5079 * Stack space is very limited. Avoid big data buffers or things like
5082 Having only the stack as writable memory limits means we cannot use
5083 normal global data to share information between the code. But it
5084 turned out that the implementation of U-Boot can be greatly
5085 simplified by making a global data structure (gd_t) available to all
5086 functions. We could pass a pointer to this data as argument to _all_
5087 functions, but this would bloat the code. Instead we use a feature of
5088 the GCC compiler (Global Register Variables) to share the data: we
5089 place a pointer (gd) to the global data into a register which we
5090 reserve for this purpose.
5092 When choosing a register for such a purpose we are restricted by the
5093 relevant (E)ABI specifications for the current architecture, and by
5094 GCC's implementation.
5096 For PowerPC, the following registers have specific use:
5098 R2: reserved for system use
5099 R3-R4: parameter passing and return values
5100 R5-R10: parameter passing
5101 R13: small data area pointer
5105 (U-Boot also uses R12 as internal GOT pointer. r12
5106 is a volatile register so r12 needs to be reset when
5107 going back and forth between asm and C)
5109 ==> U-Boot will use R2 to hold a pointer to the global data
5111 Note: on PPC, we could use a static initializer (since the
5112 address of the global data structure is known at compile time),
5113 but it turned out that reserving a register results in somewhat
5114 smaller code - although the code savings are not that big (on
5115 average for all boards 752 bytes for the whole U-Boot image,
5116 624 text + 127 data).
5118 On ARM, the following registers are used:
5120 R0: function argument word/integer result
5121 R1-R3: function argument word
5122 R9: platform specific
5123 R10: stack limit (used only if stack checking is enabled)
5124 R11: argument (frame) pointer
5125 R12: temporary workspace
5128 R15: program counter
5130 ==> U-Boot will use R9 to hold a pointer to the global data
5132 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5134 On Nios II, the ABI is documented here:
5135 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5137 ==> U-Boot will use gp to hold a pointer to the global data
5139 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5140 to access small data sections, so gp is free.
5142 On NDS32, the following registers are used:
5144 R0-R1: argument/return
5146 R15: temporary register for assembler
5147 R16: trampoline register
5148 R28: frame pointer (FP)
5149 R29: global pointer (GP)
5150 R30: link register (LP)
5151 R31: stack pointer (SP)
5152 PC: program counter (PC)
5154 ==> U-Boot will use R10 to hold a pointer to the global data
5156 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5157 or current versions of GCC may "optimize" the code too much.
5162 U-Boot runs in system state and uses physical addresses, i.e. the
5163 MMU is not used either for address mapping nor for memory protection.
5165 The available memory is mapped to fixed addresses using the memory
5166 controller. In this process, a contiguous block is formed for each
5167 memory type (Flash, SDRAM, SRAM), even when it consists of several
5168 physical memory banks.
5170 U-Boot is installed in the first 128 kB of the first Flash bank (on
5171 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5172 booting and sizing and initializing DRAM, the code relocates itself
5173 to the upper end of DRAM. Immediately below the U-Boot code some
5174 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5175 configuration setting]. Below that, a structure with global Board
5176 Info data is placed, followed by the stack (growing downward).
5178 Additionally, some exception handler code is copied to the low 8 kB
5179 of DRAM (0x00000000 ... 0x00001FFF).
5181 So a typical memory configuration with 16 MB of DRAM could look like
5184 0x0000 0000 Exception Vector code
5187 0x0000 2000 Free for Application Use
5193 0x00FB FF20 Monitor Stack (Growing downward)
5194 0x00FB FFAC Board Info Data and permanent copy of global data
5195 0x00FC 0000 Malloc Arena
5198 0x00FE 0000 RAM Copy of Monitor Code
5199 ... eventually: LCD or video framebuffer
5200 ... eventually: pRAM (Protected RAM - unchanged by reset)
5201 0x00FF FFFF [End of RAM]
5204 System Initialization:
5205 ----------------------
5207 In the reset configuration, U-Boot starts at the reset entry point
5208 (on most PowerPC systems at address 0x00000100). Because of the reset
5209 configuration for CS0# this is a mirror of the on board Flash memory.
5210 To be able to re-map memory U-Boot then jumps to its link address.
5211 To be able to implement the initialization code in C, a (small!)
5212 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5213 which provide such a feature like), or in a locked part of the data
5214 cache. After that, U-Boot initializes the CPU core, the caches and
5217 Next, all (potentially) available memory banks are mapped using a
5218 preliminary mapping. For example, we put them on 512 MB boundaries
5219 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5220 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5221 programmed for SDRAM access. Using the temporary configuration, a
5222 simple memory test is run that determines the size of the SDRAM
5225 When there is more than one SDRAM bank, and the banks are of
5226 different size, the largest is mapped first. For equal size, the first
5227 bank (CS2#) is mapped first. The first mapping is always for address
5228 0x00000000, with any additional banks following immediately to create
5229 contiguous memory starting from 0.
5231 Then, the monitor installs itself at the upper end of the SDRAM area
5232 and allocates memory for use by malloc() and for the global Board
5233 Info data; also, the exception vector code is copied to the low RAM
5234 pages, and the final stack is set up.
5236 Only after this relocation will you have a "normal" C environment;
5237 until that you are restricted in several ways, mostly because you are
5238 running from ROM, and because the code will have to be relocated to a
5242 U-Boot Porting Guide:
5243 ----------------------
5245 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5249 int main(int argc, char *argv[])
5251 sighandler_t no_more_time;
5253 signal(SIGALRM, no_more_time);
5254 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5256 if (available_money > available_manpower) {
5257 Pay consultant to port U-Boot;
5261 Download latest U-Boot source;
5263 Subscribe to u-boot mailing list;
5266 email("Hi, I am new to U-Boot, how do I get started?");
5269 Read the README file in the top level directory;
5270 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5271 Read applicable doc/*.README;
5272 Read the source, Luke;
5273 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5276 if (available_money > toLocalCurrency ($2500))
5279 Add a lot of aggravation and time;
5281 if (a similar board exists) { /* hopefully... */
5282 cp -a board/<similar> board/<myboard>
5283 cp include/configs/<similar>.h include/configs/<myboard>.h
5285 Create your own board support subdirectory;
5286 Create your own board include/configs/<myboard>.h file;
5288 Edit new board/<myboard> files
5289 Edit new include/configs/<myboard>.h
5294 Add / modify source code;
5298 email("Hi, I am having problems...");
5300 Send patch file to the U-Boot email list;
5301 if (reasonable critiques)
5302 Incorporate improvements from email list code review;
5304 Defend code as written;
5310 void no_more_time (int sig)
5319 All contributions to U-Boot should conform to the Linux kernel
5320 coding style; see the file "Documentation/CodingStyle" and the script
5321 "scripts/Lindent" in your Linux kernel source directory.
5323 Source files originating from a different project (for example the
5324 MTD subsystem) are generally exempt from these guidelines and are not
5325 reformatted to ease subsequent migration to newer versions of those
5328 Please note that U-Boot is implemented in C (and to some small parts in
5329 Assembler); no C++ is used, so please do not use C++ style comments (//)
5332 Please also stick to the following formatting rules:
5333 - remove any trailing white space
5334 - use TAB characters for indentation and vertical alignment, not spaces
5335 - make sure NOT to use DOS '\r\n' line feeds
5336 - do not add more than 2 consecutive empty lines to source files
5337 - do not add trailing empty lines to source files
5339 Submissions which do not conform to the standards may be returned
5340 with a request to reformat the changes.
5346 Since the number of patches for U-Boot is growing, we need to
5347 establish some rules. Submissions which do not conform to these rules
5348 may be rejected, even when they contain important and valuable stuff.
5350 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5352 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5353 see http://lists.denx.de/mailman/listinfo/u-boot
5355 When you send a patch, please include the following information with
5358 * For bug fixes: a description of the bug and how your patch fixes
5359 this bug. Please try to include a way of demonstrating that the
5360 patch actually fixes something.
5362 * For new features: a description of the feature and your
5365 * A CHANGELOG entry as plaintext (separate from the patch)
5367 * For major contributions, add a MAINTAINERS file with your
5368 information and associated file and directory references.
5370 * When you add support for a new board, don't forget to add a
5371 maintainer e-mail address to the boards.cfg file, too.
5373 * If your patch adds new configuration options, don't forget to
5374 document these in the README file.
5376 * The patch itself. If you are using git (which is *strongly*
5377 recommended) you can easily generate the patch using the
5378 "git format-patch". If you then use "git send-email" to send it to
5379 the U-Boot mailing list, you will avoid most of the common problems
5380 with some other mail clients.
5382 If you cannot use git, use "diff -purN OLD NEW". If your version of
5383 diff does not support these options, then get the latest version of
5386 The current directory when running this command shall be the parent
5387 directory of the U-Boot source tree (i. e. please make sure that
5388 your patch includes sufficient directory information for the
5391 We prefer patches as plain text. MIME attachments are discouraged,
5392 and compressed attachments must not be used.
5394 * If one logical set of modifications affects or creates several
5395 files, all these changes shall be submitted in a SINGLE patch file.
5397 * Changesets that contain different, unrelated modifications shall be
5398 submitted as SEPARATE patches, one patch per changeset.
5403 * Before sending the patch, run the buildman script on your patched
5404 source tree and make sure that no errors or warnings are reported
5405 for any of the boards.
5407 * Keep your modifications to the necessary minimum: A patch
5408 containing several unrelated changes or arbitrary reformats will be
5409 returned with a request to re-formatting / split it.
5411 * If you modify existing code, make sure that your new code does not
5412 add to the memory footprint of the code ;-) Small is beautiful!
5413 When adding new features, these should compile conditionally only
5414 (using #ifdef), and the resulting code with the new feature
5415 disabled must not need more memory than the old code without your
5418 * Remember that there is a size limit of 100 kB per message on the
5419 u-boot mailing list. Bigger patches will be moderated. If they are
5420 reasonable and not too big, they will be acknowledged. But patches
5421 bigger than the size limit should be avoided.