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_PORTIO * Port I/O
818 CONFIG_CMD_READ * Read raw data from partition
819 CONFIG_CMD_REGINFO * Register dump
820 CONFIG_CMD_RUN run command in env variable
821 CONFIG_CMD_SANDBOX * sb command to access sandbox features
822 CONFIG_CMD_SAVES * save S record dump
823 CONFIG_CMD_SDRAM * print SDRAM configuration information
824 (requires CONFIG_CMD_I2C)
825 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
826 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
827 CONFIG_CMD_SOURCE "source" command Support
828 CONFIG_CMD_SPI * SPI serial bus support
829 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
830 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
831 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
832 CONFIG_CMD_TIMER * access to the system tick timer
833 CONFIG_CMD_USB * USB support
834 CONFIG_CMD_CDP * Cisco Discover Protocol support
835 CONFIG_CMD_XIMG Load part of Multi Image
836 CONFIG_CMD_UUID * Generate random UUID or GUID string
838 EXAMPLE: If you want all functions except of network
839 support you can write:
841 #include "config_cmd_all.h"
842 #undef CONFIG_CMD_NET
845 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
847 Note: Don't enable the "icache" and "dcache" commands
848 (configuration option CONFIG_CMD_CACHE) unless you know
849 what you (and your U-Boot users) are doing. Data
850 cache cannot be enabled on systems like the
851 8xx (where accesses to the IMMR region must be
852 uncached), and it cannot be disabled on all other
853 systems where we (mis-) use the data cache to hold an
854 initial stack and some data.
857 XXX - this list needs to get updated!
859 - Removal of commands
860 If no commands are needed to boot, you can disable
861 CONFIG_CMDLINE to remove them. In this case, the command line
862 will not be available, and when U-Boot wants to execute the
863 boot command (on start-up) it will call board_run_command()
864 instead. This can reduce image size significantly for very
865 simple boot procedures.
867 - Regular expression support:
869 If this variable is defined, U-Boot is linked against
870 the SLRE (Super Light Regular Expression) library,
871 which adds regex support to some commands, as for
872 example "env grep" and "setexpr".
876 If this variable is defined, U-Boot will use a device tree
877 to configure its devices, instead of relying on statically
878 compiled #defines in the board file. This option is
879 experimental and only available on a few boards. The device
880 tree is available in the global data as gd->fdt_blob.
882 U-Boot needs to get its device tree from somewhere. This can
883 be done using one of the three options below:
886 If this variable is defined, U-Boot will embed a device tree
887 binary in its image. This device tree file should be in the
888 board directory and called <soc>-<board>.dts. The binary file
889 is then picked up in board_init_f() and made available through
890 the global data structure as gd->blob.
893 If this variable is defined, U-Boot will build a device tree
894 binary. It will be called u-boot.dtb. Architecture-specific
895 code will locate it at run-time. Generally this works by:
897 cat u-boot.bin u-boot.dtb >image.bin
899 and in fact, U-Boot does this for you, creating a file called
900 u-boot-dtb.bin which is useful in the common case. You can
901 still use the individual files if you need something more
905 If this variable is defined, U-Boot will use the device tree
906 provided by the board at runtime instead of embedding one with
907 the image. Only boards defining board_fdt_blob_setup() support
908 this option (see include/fdtdec.h file).
912 If this variable is defined, it enables watchdog
913 support for the SoC. There must be support in the SoC
914 specific code for a watchdog. For the 8xx
915 CPUs, the SIU Watchdog feature is enabled in the SYPCR
916 register. When supported for a specific SoC is
917 available, then no further board specific code should
921 When using a watchdog circuitry external to the used
922 SoC, then define this variable and provide board
923 specific code for the "hw_watchdog_reset" function.
925 CONFIG_AT91_HW_WDT_TIMEOUT
926 specify the timeout in seconds. default 2 seconds.
929 CONFIG_VERSION_VARIABLE
930 If this variable is defined, an environment variable
931 named "ver" is created by U-Boot showing the U-Boot
932 version as printed by the "version" command.
933 Any change to this variable will be reverted at the
938 When CONFIG_CMD_DATE is selected, the type of the RTC
939 has to be selected, too. Define exactly one of the
942 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
943 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
944 CONFIG_RTC_MC146818 - use MC146818 RTC
945 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
946 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
947 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
948 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
949 CONFIG_RTC_DS164x - use Dallas DS164x RTC
950 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
951 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
952 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
953 CONFIG_SYS_RV3029_TCR - enable trickle charger on
956 Note that if the RTC uses I2C, then the I2C interface
957 must also be configured. See I2C Support, below.
960 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
962 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
963 chip-ngpio pairs that tell the PCA953X driver the number of
964 pins supported by a particular chip.
966 Note that if the GPIO device uses I2C, then the I2C interface
967 must also be configured. See I2C Support, below.
970 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
971 accesses and can checksum them or write a list of them out
972 to memory. See the 'iotrace' command for details. This is
973 useful for testing device drivers since it can confirm that
974 the driver behaves the same way before and after a code
975 change. Currently this is supported on sandbox and arm. To
976 add support for your architecture, add '#include <iotrace.h>'
977 to the bottom of arch/<arch>/include/asm/io.h and test.
979 Example output from the 'iotrace stats' command is below.
980 Note that if the trace buffer is exhausted, the checksum will
981 still continue to operate.
984 Start: 10000000 (buffer start address)
985 Size: 00010000 (buffer size)
986 Offset: 00000120 (current buffer offset)
987 Output: 10000120 (start + offset)
988 Count: 00000018 (number of trace records)
989 CRC32: 9526fb66 (CRC32 of all trace records)
993 When CONFIG_TIMESTAMP is selected, the timestamp
994 (date and time) of an image is printed by image
995 commands like bootm or iminfo. This option is
996 automatically enabled when you select CONFIG_CMD_DATE .
998 - Partition Labels (disklabels) Supported:
999 Zero or more of the following:
1000 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1001 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1002 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1003 bootloader. Note 2TB partition limit; see
1005 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1007 If IDE or SCSI support is enabled (CONFIG_IDE or
1008 CONFIG_SCSI) you must configure support for at
1009 least one non-MTD partition type as well.
1012 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1013 board configurations files but used nowhere!
1015 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1016 be performed by calling the function
1017 ide_set_reset(int reset)
1018 which has to be defined in a board specific file
1023 Set this to enable ATAPI support.
1028 Set this to enable support for disks larger than 137GB
1029 Also look at CONFIG_SYS_64BIT_LBA.
1030 Whithout these , LBA48 support uses 32bit variables and will 'only'
1031 support disks up to 2.1TB.
1033 CONFIG_SYS_64BIT_LBA:
1034 When enabled, makes the IDE subsystem use 64bit sector addresses.
1038 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1039 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1040 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1041 maximum numbers of LUNs, SCSI ID's and target
1044 The environment variable 'scsidevs' is set to the number of
1045 SCSI devices found during the last scan.
1047 - NETWORK Support (PCI):
1049 Support for Intel 8254x/8257x gigabit chips.
1052 Utility code for direct access to the SPI bus on Intel 8257x.
1053 This does not do anything useful unless you set at least one
1054 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1056 CONFIG_E1000_SPI_GENERIC
1057 Allow generic access to the SPI bus on the Intel 8257x, for
1058 example with the "sspi" command.
1061 Management command for E1000 devices. When used on devices
1062 with SPI support you can reprogram the EEPROM from U-Boot.
1065 Support for Intel 82557/82559/82559ER chips.
1066 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1067 write routine for first time initialisation.
1070 Support for Digital 2114x chips.
1071 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1072 modem chip initialisation (KS8761/QS6611).
1075 Support for National dp83815 chips.
1078 Support for National dp8382[01] gigabit chips.
1080 - NETWORK Support (other):
1082 CONFIG_DRIVER_AT91EMAC
1083 Support for AT91RM9200 EMAC.
1086 Define this to use reduced MII inteface
1088 CONFIG_DRIVER_AT91EMAC_QUIET
1089 If this defined, the driver is quiet.
1090 The driver doen't show link status messages.
1092 CONFIG_CALXEDA_XGMAC
1093 Support for the Calxeda XGMAC device
1096 Support for SMSC's LAN91C96 chips.
1098 CONFIG_LAN91C96_USE_32_BIT
1099 Define this to enable 32 bit addressing
1102 Support for SMSC's LAN91C111 chip
1104 CONFIG_SMC91111_BASE
1105 Define this to hold the physical address
1106 of the device (I/O space)
1108 CONFIG_SMC_USE_32_BIT
1109 Define this if data bus is 32 bits
1111 CONFIG_SMC_USE_IOFUNCS
1112 Define this to use i/o functions instead of macros
1113 (some hardware wont work with macros)
1115 CONFIG_DRIVER_TI_EMAC
1116 Support for davinci emac
1118 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1119 Define this if you have more then 3 PHYs.
1122 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1124 CONFIG_FTGMAC100_EGIGA
1125 Define this to use GE link update with gigabit PHY.
1126 Define this if FTGMAC100 is connected to gigabit PHY.
1127 If your system has 10/100 PHY only, it might not occur
1128 wrong behavior. Because PHY usually return timeout or
1129 useless data when polling gigabit status and gigabit
1130 control registers. This behavior won't affect the
1131 correctnessof 10/100 link speed update.
1134 Support for SMSC's LAN911x and LAN921x chips
1137 Define this to hold the physical address
1138 of the device (I/O space)
1140 CONFIG_SMC911X_32_BIT
1141 Define this if data bus is 32 bits
1143 CONFIG_SMC911X_16_BIT
1144 Define this if data bus is 16 bits. If your processor
1145 automatically converts one 32 bit word to two 16 bit
1146 words you may also try CONFIG_SMC911X_32_BIT.
1149 Support for Renesas on-chip Ethernet controller
1151 CONFIG_SH_ETHER_USE_PORT
1152 Define the number of ports to be used
1154 CONFIG_SH_ETHER_PHY_ADDR
1155 Define the ETH PHY's address
1157 CONFIG_SH_ETHER_CACHE_WRITEBACK
1158 If this option is set, the driver enables cache flush.
1162 Support for PWM module on the imx6.
1166 Support TPM devices.
1168 CONFIG_TPM_TIS_INFINEON
1169 Support for Infineon i2c bus TPM devices. Only one device
1170 per system is supported at this time.
1172 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1173 Define the burst count bytes upper limit
1176 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1178 CONFIG_TPM_ST33ZP24_I2C
1179 Support for STMicroelectronics ST33ZP24 I2C devices.
1180 Requires TPM_ST33ZP24 and I2C.
1182 CONFIG_TPM_ST33ZP24_SPI
1183 Support for STMicroelectronics ST33ZP24 SPI devices.
1184 Requires TPM_ST33ZP24 and SPI.
1186 CONFIG_TPM_ATMEL_TWI
1187 Support for Atmel TWI TPM device. Requires I2C support.
1190 Support for generic parallel port TPM devices. Only one device
1191 per system is supported at this time.
1193 CONFIG_TPM_TIS_BASE_ADDRESS
1194 Base address where the generic TPM device is mapped
1195 to. Contemporary x86 systems usually map it at
1199 Add tpm monitor functions.
1200 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1201 provides monitor access to authorized functions.
1204 Define this to enable the TPM support library which provides
1205 functional interfaces to some TPM commands.
1206 Requires support for a TPM device.
1208 CONFIG_TPM_AUTH_SESSIONS
1209 Define this to enable authorized functions in the TPM library.
1210 Requires CONFIG_TPM and CONFIG_SHA1.
1213 At the moment only the UHCI host controller is
1214 supported (PIP405, MIP405); define
1215 CONFIG_USB_UHCI to enable it.
1216 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1217 and define CONFIG_USB_STORAGE to enable the USB
1220 Supported are USB Keyboards and USB Floppy drives
1223 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1224 txfilltuning field in the EHCI controller on reset.
1226 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1227 HW module registers.
1230 Define the below if you wish to use the USB console.
1231 Once firmware is rebuilt from a serial console issue the
1232 command "setenv stdin usbtty; setenv stdout usbtty" and
1233 attach your USB cable. The Unix command "dmesg" should print
1234 it has found a new device. The environment variable usbtty
1235 can be set to gserial or cdc_acm to enable your device to
1236 appear to a USB host as a Linux gserial device or a
1237 Common Device Class Abstract Control Model serial device.
1238 If you select usbtty = gserial you should be able to enumerate
1240 # modprobe usbserial vendor=0xVendorID product=0xProductID
1241 else if using cdc_acm, simply setting the environment
1242 variable usbtty to be cdc_acm should suffice. The following
1243 might be defined in YourBoardName.h
1246 Define this to build a UDC device
1249 Define this to have a tty type of device available to
1250 talk to the UDC device
1253 Define this to enable the high speed support for usb
1254 device and usbtty. If this feature is enabled, a routine
1255 int is_usbd_high_speed(void)
1256 also needs to be defined by the driver to dynamically poll
1257 whether the enumeration has succeded at high speed or full
1260 CONFIG_SYS_CONSOLE_IS_IN_ENV
1261 Define this if you want stdin, stdout &/or stderr to
1264 If you have a USB-IF assigned VendorID then you may wish to
1265 define your own vendor specific values either in BoardName.h
1266 or directly in usbd_vendor_info.h. If you don't define
1267 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1268 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1269 should pretend to be a Linux device to it's target host.
1271 CONFIG_USBD_MANUFACTURER
1272 Define this string as the name of your company for
1273 - CONFIG_USBD_MANUFACTURER "my company"
1275 CONFIG_USBD_PRODUCT_NAME
1276 Define this string as the name of your product
1277 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1279 CONFIG_USBD_VENDORID
1280 Define this as your assigned Vendor ID from the USB
1281 Implementors Forum. This *must* be a genuine Vendor ID
1282 to avoid polluting the USB namespace.
1283 - CONFIG_USBD_VENDORID 0xFFFF
1285 CONFIG_USBD_PRODUCTID
1286 Define this as the unique Product ID
1288 - CONFIG_USBD_PRODUCTID 0xFFFF
1290 - ULPI Layer Support:
1291 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1292 the generic ULPI layer. The generic layer accesses the ULPI PHY
1293 via the platform viewport, so you need both the genric layer and
1294 the viewport enabled. Currently only Chipidea/ARC based
1295 viewport is supported.
1296 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1297 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1298 If your ULPI phy needs a different reference clock than the
1299 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1300 the appropriate value in Hz.
1303 The MMC controller on the Intel PXA is supported. To
1304 enable this define CONFIG_MMC. The MMC can be
1305 accessed from the boot prompt by mapping the device
1306 to physical memory similar to flash. Command line is
1307 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1308 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1311 Support for Renesas on-chip MMCIF controller
1313 CONFIG_SH_MMCIF_ADDR
1314 Define the base address of MMCIF registers
1317 Define the clock frequency for MMCIF
1319 CONFIG_SUPPORT_EMMC_BOOT
1320 Enable some additional features of the eMMC boot partitions.
1322 CONFIG_SUPPORT_EMMC_RPMB
1323 Enable the commands for reading, writing and programming the
1324 key for the Replay Protection Memory Block partition in eMMC.
1326 - USB Device Firmware Update (DFU) class support:
1327 CONFIG_USB_FUNCTION_DFU
1328 This enables the USB portion of the DFU USB class
1331 This enables the command "dfu" which is used to have
1332 U-Boot create a DFU class device via USB. This command
1333 requires that the "dfu_alt_info" environment variable be
1334 set and define the alt settings to expose to the host.
1337 This enables support for exposing (e)MMC devices via DFU.
1340 This enables support for exposing NAND devices via DFU.
1343 This enables support for exposing RAM via DFU.
1344 Note: DFU spec refer to non-volatile memory usage, but
1345 allow usages beyond the scope of spec - here RAM usage,
1346 one that would help mostly the developer.
1348 CONFIG_SYS_DFU_DATA_BUF_SIZE
1349 Dfu transfer uses a buffer before writing data to the
1350 raw storage device. Make the size (in bytes) of this buffer
1351 configurable. The size of this buffer is also configurable
1352 through the "dfu_bufsiz" environment variable.
1354 CONFIG_SYS_DFU_MAX_FILE_SIZE
1355 When updating files rather than the raw storage device,
1356 we use a static buffer to copy the file into and then write
1357 the buffer once we've been given the whole file. Define
1358 this to the maximum filesize (in bytes) for the buffer.
1359 Default is 4 MiB if undefined.
1361 DFU_DEFAULT_POLL_TIMEOUT
1362 Poll timeout [ms], is the timeout a device can send to the
1363 host. The host must wait for this timeout before sending
1364 a subsequent DFU_GET_STATUS request to the device.
1366 DFU_MANIFEST_POLL_TIMEOUT
1367 Poll timeout [ms], which the device sends to the host when
1368 entering dfuMANIFEST state. Host waits this timeout, before
1369 sending again an USB request to the device.
1371 - USB Device Android Fastboot support:
1372 CONFIG_USB_FUNCTION_FASTBOOT
1373 This enables the USB part of the fastboot gadget
1376 This enables the command "fastboot" which enables the Android
1377 fastboot mode for the platform's USB device. Fastboot is a USB
1378 protocol for downloading images, flashing and device control
1379 used on Android devices.
1380 See doc/README.android-fastboot for more information.
1382 CONFIG_ANDROID_BOOT_IMAGE
1383 This enables support for booting images which use the Android
1384 image format header.
1386 CONFIG_FASTBOOT_BUF_ADDR
1387 The fastboot protocol requires a large memory buffer for
1388 downloads. Define this to the starting RAM address to use for
1391 CONFIG_FASTBOOT_BUF_SIZE
1392 The fastboot protocol requires a large memory buffer for
1393 downloads. This buffer should be as large as possible for a
1394 platform. Define this to the size available RAM for fastboot.
1396 CONFIG_FASTBOOT_FLASH
1397 The fastboot protocol includes a "flash" command for writing
1398 the downloaded image to a non-volatile storage device. Define
1399 this to enable the "fastboot flash" command.
1401 CONFIG_FASTBOOT_FLASH_MMC_DEV
1402 The fastboot "flash" command requires additional information
1403 regarding the non-volatile storage device. Define this to
1404 the eMMC device that fastboot should use to store the image.
1406 CONFIG_FASTBOOT_GPT_NAME
1407 The fastboot "flash" command supports writing the downloaded
1408 image to the Protective MBR and the Primary GUID Partition
1409 Table. (Additionally, this downloaded image is post-processed
1410 to generate and write the Backup GUID Partition Table.)
1411 This occurs when the specified "partition name" on the
1412 "fastboot flash" command line matches this value.
1413 The default is "gpt" if undefined.
1415 CONFIG_FASTBOOT_MBR_NAME
1416 The fastboot "flash" command supports writing the downloaded
1418 This occurs when the "partition name" specified on the
1419 "fastboot flash" command line matches this value.
1420 If not defined the default value "mbr" is used.
1422 - Journaling Flash filesystem support:
1424 Define these for a default partition on a NAND device
1426 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1427 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1428 Define these for a default partition on a NOR device
1431 See Kconfig help for available keyboard drivers.
1435 Define this to enable a custom keyboard support.
1436 This simply calls drv_keyboard_init() which must be
1437 defined in your board-specific files. This option is deprecated
1438 and is only used by novena. For new boards, use driver model
1443 Enable the Freescale DIU video driver. Reference boards for
1444 SOCs that have a DIU should define this macro to enable DIU
1445 support, and should also define these other macros:
1450 CONFIG_VIDEO_SW_CURSOR
1451 CONFIG_VGA_AS_SINGLE_DEVICE
1453 CONFIG_VIDEO_BMP_LOGO
1455 The DIU driver will look for the 'video-mode' environment
1456 variable, and if defined, enable the DIU as a console during
1457 boot. See the documentation file doc/README.video for a
1458 description of this variable.
1460 - LCD Support: CONFIG_LCD
1462 Define this to enable LCD support (for output to LCD
1463 display); also select one of the supported displays
1464 by defining one of these:
1468 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1470 CONFIG_NEC_NL6448AC33:
1472 NEC NL6448AC33-18. Active, color, single scan.
1474 CONFIG_NEC_NL6448BC20
1476 NEC NL6448BC20-08. 6.5", 640x480.
1477 Active, color, single scan.
1479 CONFIG_NEC_NL6448BC33_54
1481 NEC NL6448BC33-54. 10.4", 640x480.
1482 Active, color, single scan.
1486 Sharp 320x240. Active, color, single scan.
1487 It isn't 16x9, and I am not sure what it is.
1489 CONFIG_SHARP_LQ64D341
1491 Sharp LQ64D341 display, 640x480.
1492 Active, color, single scan.
1496 HLD1045 display, 640x480.
1497 Active, color, single scan.
1501 Optrex CBL50840-2 NF-FW 99 22 M5
1503 Hitachi LMG6912RPFC-00T
1507 320x240. Black & white.
1509 CONFIG_LCD_ALIGNMENT
1511 Normally the LCD is page-aligned (typically 4KB). If this is
1512 defined then the LCD will be aligned to this value instead.
1513 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1514 here, since it is cheaper to change data cache settings on
1515 a per-section basis.
1520 Sometimes, for example if the display is mounted in portrait
1521 mode or even if it's mounted landscape but rotated by 180degree,
1522 we need to rotate our content of the display relative to the
1523 framebuffer, so that user can read the messages which are
1525 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1526 initialized with a given rotation from "vl_rot" out of
1527 "vidinfo_t" which is provided by the board specific code.
1528 The value for vl_rot is coded as following (matching to
1529 fbcon=rotate:<n> linux-kernel commandline):
1530 0 = no rotation respectively 0 degree
1531 1 = 90 degree rotation
1532 2 = 180 degree rotation
1533 3 = 270 degree rotation
1535 If CONFIG_LCD_ROTATION is not defined, the console will be
1536 initialized with 0degree rotation.
1540 Support drawing of RLE8-compressed bitmaps on the LCD.
1544 Enables an 'i2c edid' command which can read EDID
1545 information over I2C from an attached LCD display.
1547 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1549 If this option is set, the environment is checked for
1550 a variable "splashimage". If found, the usual display
1551 of logo, copyright and system information on the LCD
1552 is suppressed and the BMP image at the address
1553 specified in "splashimage" is loaded instead. The
1554 console is redirected to the "nulldev", too. This
1555 allows for a "silent" boot where a splash screen is
1556 loaded very quickly after power-on.
1558 CONFIG_SPLASHIMAGE_GUARD
1560 If this option is set, then U-Boot will prevent the environment
1561 variable "splashimage" from being set to a problematic address
1562 (see doc/README.displaying-bmps).
1563 This option is useful for targets where, due to alignment
1564 restrictions, an improperly aligned BMP image will cause a data
1565 abort. If you think you will not have problems with unaligned
1566 accesses (for example because your toolchain prevents them)
1567 there is no need to set this option.
1569 CONFIG_SPLASH_SCREEN_ALIGN
1571 If this option is set the splash image can be freely positioned
1572 on the screen. Environment variable "splashpos" specifies the
1573 position as "x,y". If a positive number is given it is used as
1574 number of pixel from left/top. If a negative number is given it
1575 is used as number of pixel from right/bottom. You can also
1576 specify 'm' for centering the image.
1579 setenv splashpos m,m
1580 => image at center of screen
1582 setenv splashpos 30,20
1583 => image at x = 30 and y = 20
1585 setenv splashpos -10,m
1586 => vertically centered image
1587 at x = dspWidth - bmpWidth - 9
1589 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1591 If this option is set, additionally to standard BMP
1592 images, gzipped BMP images can be displayed via the
1593 splashscreen support or the bmp command.
1595 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1597 If this option is set, 8-bit RLE compressed BMP images
1598 can be displayed via the splashscreen support or the
1601 - Compression support:
1604 Enabled by default to support gzip compressed images.
1608 If this option is set, support for bzip2 compressed
1609 images is included. If not, only uncompressed and gzip
1610 compressed images are supported.
1612 NOTE: the bzip2 algorithm requires a lot of RAM, so
1613 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1619 The address of PHY on MII bus.
1621 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1623 The clock frequency of the MII bus
1625 CONFIG_PHY_RESET_DELAY
1627 Some PHY like Intel LXT971A need extra delay after
1628 reset before any MII register access is possible.
1629 For such PHY, set this option to the usec delay
1630 required. (minimum 300usec for LXT971A)
1632 CONFIG_PHY_CMD_DELAY (ppc4xx)
1634 Some PHY like Intel LXT971A need extra delay after
1635 command issued before MII status register can be read
1640 Define a default value for the IP address to use for
1641 the default Ethernet interface, in case this is not
1642 determined through e.g. bootp.
1643 (Environment variable "ipaddr")
1645 - Server IP address:
1648 Defines a default value for the IP address of a TFTP
1649 server to contact when using the "tftboot" command.
1650 (Environment variable "serverip")
1652 CONFIG_KEEP_SERVERADDR
1654 Keeps the server's MAC address, in the env 'serveraddr'
1655 for passing to bootargs (like Linux's netconsole option)
1657 - Gateway IP address:
1660 Defines a default value for the IP address of the
1661 default router where packets to other networks are
1663 (Environment variable "gatewayip")
1668 Defines a default value for the subnet mask (or
1669 routing prefix) which is used to determine if an IP
1670 address belongs to the local subnet or needs to be
1671 forwarded through a router.
1672 (Environment variable "netmask")
1674 - Multicast TFTP Mode:
1677 Defines whether you want to support multicast TFTP as per
1678 rfc-2090; for example to work with atftp. Lets lots of targets
1679 tftp down the same boot image concurrently. Note: the Ethernet
1680 driver in use must provide a function: mcast() to join/leave a
1683 - BOOTP Recovery Mode:
1684 CONFIG_BOOTP_RANDOM_DELAY
1686 If you have many targets in a network that try to
1687 boot using BOOTP, you may want to avoid that all
1688 systems send out BOOTP requests at precisely the same
1689 moment (which would happen for instance at recovery
1690 from a power failure, when all systems will try to
1691 boot, thus flooding the BOOTP server. Defining
1692 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1693 inserted before sending out BOOTP requests. The
1694 following delays are inserted then:
1696 1st BOOTP request: delay 0 ... 1 sec
1697 2nd BOOTP request: delay 0 ... 2 sec
1698 3rd BOOTP request: delay 0 ... 4 sec
1700 BOOTP requests: delay 0 ... 8 sec
1702 CONFIG_BOOTP_ID_CACHE_SIZE
1704 BOOTP packets are uniquely identified using a 32-bit ID. The
1705 server will copy the ID from client requests to responses and
1706 U-Boot will use this to determine if it is the destination of
1707 an incoming response. Some servers will check that addresses
1708 aren't in use before handing them out (usually using an ARP
1709 ping) and therefore take up to a few hundred milliseconds to
1710 respond. Network congestion may also influence the time it
1711 takes for a response to make it back to the client. If that
1712 time is too long, U-Boot will retransmit requests. In order
1713 to allow earlier responses to still be accepted after these
1714 retransmissions, U-Boot's BOOTP client keeps a small cache of
1715 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1716 cache. The default is to keep IDs for up to four outstanding
1717 requests. Increasing this will allow U-Boot to accept offers
1718 from a BOOTP client in networks with unusually high latency.
1720 - DHCP Advanced Options:
1721 You can fine tune the DHCP functionality by defining
1722 CONFIG_BOOTP_* symbols:
1724 CONFIG_BOOTP_SUBNETMASK
1725 CONFIG_BOOTP_GATEWAY
1726 CONFIG_BOOTP_HOSTNAME
1727 CONFIG_BOOTP_NISDOMAIN
1728 CONFIG_BOOTP_BOOTPATH
1729 CONFIG_BOOTP_BOOTFILESIZE
1732 CONFIG_BOOTP_SEND_HOSTNAME
1733 CONFIG_BOOTP_NTPSERVER
1734 CONFIG_BOOTP_TIMEOFFSET
1735 CONFIG_BOOTP_VENDOREX
1736 CONFIG_BOOTP_MAY_FAIL
1738 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1739 environment variable, not the BOOTP server.
1741 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1742 after the configured retry count, the call will fail
1743 instead of starting over. This can be used to fail over
1744 to Link-local IP address configuration if the DHCP server
1747 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1748 serverip from a DHCP server, it is possible that more
1749 than one DNS serverip is offered to the client.
1750 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1751 serverip will be stored in the additional environment
1752 variable "dnsip2". The first DNS serverip is always
1753 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1756 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1757 to do a dynamic update of a DNS server. To do this, they
1758 need the hostname of the DHCP requester.
1759 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1760 of the "hostname" environment variable is passed as
1761 option 12 to the DHCP server.
1763 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1765 A 32bit value in microseconds for a delay between
1766 receiving a "DHCP Offer" and sending the "DHCP Request".
1767 This fixes a problem with certain DHCP servers that don't
1768 respond 100% of the time to a "DHCP request". E.g. On an
1769 AT91RM9200 processor running at 180MHz, this delay needed
1770 to be *at least* 15,000 usec before a Windows Server 2003
1771 DHCP server would reply 100% of the time. I recommend at
1772 least 50,000 usec to be safe. The alternative is to hope
1773 that one of the retries will be successful but note that
1774 the DHCP timeout and retry process takes a longer than
1777 - Link-local IP address negotiation:
1778 Negotiate with other link-local clients on the local network
1779 for an address that doesn't require explicit configuration.
1780 This is especially useful if a DHCP server cannot be guaranteed
1781 to exist in all environments that the device must operate.
1783 See doc/README.link-local for more information.
1786 CONFIG_CDP_DEVICE_ID
1788 The device id used in CDP trigger frames.
1790 CONFIG_CDP_DEVICE_ID_PREFIX
1792 A two character string which is prefixed to the MAC address
1797 A printf format string which contains the ascii name of
1798 the port. Normally is set to "eth%d" which sets
1799 eth0 for the first Ethernet, eth1 for the second etc.
1801 CONFIG_CDP_CAPABILITIES
1803 A 32bit integer which indicates the device capabilities;
1804 0x00000010 for a normal host which does not forwards.
1808 An ascii string containing the version of the software.
1812 An ascii string containing the name of the platform.
1816 A 32bit integer sent on the trigger.
1818 CONFIG_CDP_POWER_CONSUMPTION
1820 A 16bit integer containing the power consumption of the
1821 device in .1 of milliwatts.
1823 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1825 A byte containing the id of the VLAN.
1827 - Status LED: CONFIG_LED_STATUS
1829 Several configurations allow to display the current
1830 status using a LED. For instance, the LED will blink
1831 fast while running U-Boot code, stop blinking as
1832 soon as a reply to a BOOTP request was received, and
1833 start blinking slow once the Linux kernel is running
1834 (supported by a status LED driver in the Linux
1835 kernel). Defining CONFIG_LED_STATUS enables this
1840 CONFIG_LED_STATUS_GPIO
1841 The status LED can be connected to a GPIO pin.
1842 In such cases, the gpio_led driver can be used as a
1843 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1844 to include the gpio_led driver in the U-Boot binary.
1846 CONFIG_GPIO_LED_INVERTED_TABLE
1847 Some GPIO connected LEDs may have inverted polarity in which
1848 case the GPIO high value corresponds to LED off state and
1849 GPIO low value corresponds to LED on state.
1850 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1851 with a list of GPIO LEDs that have inverted polarity.
1853 - I2C Support: CONFIG_SYS_I2C
1855 This enable the NEW i2c subsystem, and will allow you to use
1856 i2c commands at the u-boot command line (as long as you set
1857 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1858 based realtime clock chips or other i2c devices. See
1859 common/cmd_i2c.c for a description of the command line
1862 ported i2c driver to the new framework:
1863 - drivers/i2c/soft_i2c.c:
1864 - activate first bus with CONFIG_SYS_I2C_SOFT define
1865 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1866 for defining speed and slave address
1867 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1868 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1869 for defining speed and slave address
1870 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1871 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1872 for defining speed and slave address
1873 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1874 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1875 for defining speed and slave address
1877 - drivers/i2c/fsl_i2c.c:
1878 - activate i2c driver with CONFIG_SYS_I2C_FSL
1879 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1880 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1881 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1883 - If your board supports a second fsl i2c bus, define
1884 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1885 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1886 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1889 - drivers/i2c/tegra_i2c.c:
1890 - activate this driver with CONFIG_SYS_I2C_TEGRA
1891 - This driver adds 4 i2c buses with a fix speed from
1892 100000 and the slave addr 0!
1894 - drivers/i2c/ppc4xx_i2c.c
1895 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1896 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1897 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1899 - drivers/i2c/i2c_mxc.c
1900 - activate this driver with CONFIG_SYS_I2C_MXC
1901 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1902 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1903 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1904 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1905 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1906 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1907 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1908 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1909 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1910 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1911 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1912 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1913 If those defines are not set, default value is 100000
1914 for speed, and 0 for slave.
1916 - drivers/i2c/rcar_i2c.c:
1917 - activate this driver with CONFIG_SYS_I2C_RCAR
1918 - This driver adds 4 i2c buses
1920 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1921 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1922 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1923 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1924 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1925 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1926 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1927 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1928 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1930 - drivers/i2c/sh_i2c.c:
1931 - activate this driver with CONFIG_SYS_I2C_SH
1932 - This driver adds from 2 to 5 i2c buses
1934 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1935 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1936 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1937 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1938 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1939 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1940 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1941 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1942 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1943 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1944 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1946 - drivers/i2c/omap24xx_i2c.c
1947 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1948 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1949 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1950 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1951 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1952 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1953 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1954 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1955 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1956 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1957 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1959 - drivers/i2c/zynq_i2c.c
1960 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1961 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1962 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1964 - drivers/i2c/s3c24x0_i2c.c:
1965 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1966 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1967 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1968 with a fix speed from 100000 and the slave addr 0!
1970 - drivers/i2c/ihs_i2c.c
1971 - activate this driver with CONFIG_SYS_I2C_IHS
1972 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1973 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1974 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1975 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1976 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1977 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1978 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1979 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1980 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1981 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1982 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1983 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1984 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1985 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1986 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1987 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1988 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1989 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1990 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1991 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1992 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1996 CONFIG_SYS_NUM_I2C_BUSES
1997 Hold the number of i2c buses you want to use.
1999 CONFIG_SYS_I2C_DIRECT_BUS
2000 define this, if you don't use i2c muxes on your hardware.
2001 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2004 CONFIG_SYS_I2C_MAX_HOPS
2005 define how many muxes are maximal consecutively connected
2006 on one i2c bus. If you not use i2c muxes, omit this
2009 CONFIG_SYS_I2C_BUSES
2010 hold a list of buses you want to use, only used if
2011 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2012 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2013 CONFIG_SYS_NUM_I2C_BUSES = 9:
2015 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2016 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2017 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2018 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2019 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2020 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2021 {1, {I2C_NULL_HOP}}, \
2022 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2023 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2027 bus 0 on adapter 0 without a mux
2028 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2029 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2030 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2031 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2032 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2033 bus 6 on adapter 1 without a mux
2034 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2035 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2037 If you do not have i2c muxes on your board, omit this define.
2039 - Legacy I2C Support:
2040 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2041 then the following macros need to be defined (examples are
2042 from include/configs/lwmon.h):
2046 (Optional). Any commands necessary to enable the I2C
2047 controller or configure ports.
2049 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2053 The code necessary to make the I2C data line active
2054 (driven). If the data line is open collector, this
2057 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2061 The code necessary to make the I2C data line tri-stated
2062 (inactive). If the data line is open collector, this
2065 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2069 Code that returns true if the I2C data line is high,
2072 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2076 If <bit> is true, sets the I2C data line high. If it
2077 is false, it clears it (low).
2079 eg: #define I2C_SDA(bit) \
2080 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2081 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2085 If <bit> is true, sets the I2C clock line high. If it
2086 is false, it clears it (low).
2088 eg: #define I2C_SCL(bit) \
2089 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2090 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2094 This delay is invoked four times per clock cycle so this
2095 controls the rate of data transfer. The data rate thus
2096 is 1 / (I2C_DELAY * 4). Often defined to be something
2099 #define I2C_DELAY udelay(2)
2101 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2103 If your arch supports the generic GPIO framework (asm/gpio.h),
2104 then you may alternatively define the two GPIOs that are to be
2105 used as SCL / SDA. Any of the previous I2C_xxx macros will
2106 have GPIO-based defaults assigned to them as appropriate.
2108 You should define these to the GPIO value as given directly to
2109 the generic GPIO functions.
2111 CONFIG_SYS_I2C_INIT_BOARD
2113 When a board is reset during an i2c bus transfer
2114 chips might think that the current transfer is still
2115 in progress. On some boards it is possible to access
2116 the i2c SCLK line directly, either by using the
2117 processor pin as a GPIO or by having a second pin
2118 connected to the bus. If this option is defined a
2119 custom i2c_init_board() routine in boards/xxx/board.c
2120 is run early in the boot sequence.
2122 CONFIG_I2C_MULTI_BUS
2124 This option allows the use of multiple I2C buses, each of which
2125 must have a controller. At any point in time, only one bus is
2126 active. To switch to a different bus, use the 'i2c dev' command.
2127 Note that bus numbering is zero-based.
2129 CONFIG_SYS_I2C_NOPROBES
2131 This option specifies a list of I2C devices that will be skipped
2132 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2133 is set, specify a list of bus-device pairs. Otherwise, specify
2134 a 1D array of device addresses
2137 #undef CONFIG_I2C_MULTI_BUS
2138 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2140 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2142 #define CONFIG_I2C_MULTI_BUS
2143 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2145 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2147 CONFIG_SYS_SPD_BUS_NUM
2149 If defined, then this indicates the I2C bus number for DDR SPD.
2150 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2152 CONFIG_SYS_RTC_BUS_NUM
2154 If defined, then this indicates the I2C bus number for the RTC.
2155 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2157 CONFIG_SOFT_I2C_READ_REPEATED_START
2159 defining this will force the i2c_read() function in
2160 the soft_i2c driver to perform an I2C repeated start
2161 between writing the address pointer and reading the
2162 data. If this define is omitted the default behaviour
2163 of doing a stop-start sequence will be used. Most I2C
2164 devices can use either method, but some require one or
2167 - SPI Support: CONFIG_SPI
2169 Enables SPI driver (so far only tested with
2170 SPI EEPROM, also an instance works with Crystal A/D and
2171 D/As on the SACSng board)
2175 Enables the driver for SPI controller on SuperH. Currently
2176 only SH7757 is supported.
2180 Enables a software (bit-bang) SPI driver rather than
2181 using hardware support. This is a general purpose
2182 driver that only requires three general I/O port pins
2183 (two outputs, one input) to function. If this is
2184 defined, the board configuration must define several
2185 SPI configuration items (port pins to use, etc). For
2186 an example, see include/configs/sacsng.h.
2190 Enables a hardware SPI driver for general-purpose reads
2191 and writes. As with CONFIG_SOFT_SPI, the board configuration
2192 must define a list of chip-select function pointers.
2193 Currently supported on some MPC8xxx processors. For an
2194 example, see include/configs/mpc8349emds.h.
2198 Enables the driver for the SPI controllers on i.MX and MXC
2199 SoCs. Currently i.MX31/35/51 are supported.
2201 CONFIG_SYS_SPI_MXC_WAIT
2202 Timeout for waiting until spi transfer completed.
2203 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2205 - FPGA Support: CONFIG_FPGA
2207 Enables FPGA subsystem.
2209 CONFIG_FPGA_<vendor>
2211 Enables support for specific chip vendors.
2214 CONFIG_FPGA_<family>
2216 Enables support for FPGA family.
2217 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2221 Specify the number of FPGA devices to support.
2223 CONFIG_SYS_FPGA_PROG_FEEDBACK
2225 Enable printing of hash marks during FPGA configuration.
2227 CONFIG_SYS_FPGA_CHECK_BUSY
2229 Enable checks on FPGA configuration interface busy
2230 status by the configuration function. This option
2231 will require a board or device specific function to
2236 If defined, a function that provides delays in the FPGA
2237 configuration driver.
2239 CONFIG_SYS_FPGA_CHECK_CTRLC
2240 Allow Control-C to interrupt FPGA configuration
2242 CONFIG_SYS_FPGA_CHECK_ERROR
2244 Check for configuration errors during FPGA bitfile
2245 loading. For example, abort during Virtex II
2246 configuration if the INIT_B line goes low (which
2247 indicated a CRC error).
2249 CONFIG_SYS_FPGA_WAIT_INIT
2251 Maximum time to wait for the INIT_B line to de-assert
2252 after PROB_B has been de-asserted during a Virtex II
2253 FPGA configuration sequence. The default time is 500
2256 CONFIG_SYS_FPGA_WAIT_BUSY
2258 Maximum time to wait for BUSY to de-assert during
2259 Virtex II FPGA configuration. The default is 5 ms.
2261 CONFIG_SYS_FPGA_WAIT_CONFIG
2263 Time to wait after FPGA configuration. The default is
2266 - Configuration Management:
2269 Some SoCs need special image types (e.g. U-Boot binary
2270 with a special header) as build targets. By defining
2271 CONFIG_BUILD_TARGET in the SoC / board header, this
2272 special image will be automatically built upon calling
2277 If defined, this string will be added to the U-Boot
2278 version information (U_BOOT_VERSION)
2280 - Vendor Parameter Protection:
2282 U-Boot considers the values of the environment
2283 variables "serial#" (Board Serial Number) and
2284 "ethaddr" (Ethernet Address) to be parameters that
2285 are set once by the board vendor / manufacturer, and
2286 protects these variables from casual modification by
2287 the user. Once set, these variables are read-only,
2288 and write or delete attempts are rejected. You can
2289 change this behaviour:
2291 If CONFIG_ENV_OVERWRITE is #defined in your config
2292 file, the write protection for vendor parameters is
2293 completely disabled. Anybody can change or delete
2296 Alternatively, if you define _both_ an ethaddr in the
2297 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2298 Ethernet address is installed in the environment,
2299 which can be changed exactly ONCE by the user. [The
2300 serial# is unaffected by this, i. e. it remains
2303 The same can be accomplished in a more flexible way
2304 for any variable by configuring the type of access
2305 to allow for those variables in the ".flags" variable
2306 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2311 Define this variable to enable the reservation of
2312 "protected RAM", i. e. RAM which is not overwritten
2313 by U-Boot. Define CONFIG_PRAM to hold the number of
2314 kB you want to reserve for pRAM. You can overwrite
2315 this default value by defining an environment
2316 variable "pram" to the number of kB you want to
2317 reserve. Note that the board info structure will
2318 still show the full amount of RAM. If pRAM is
2319 reserved, a new environment variable "mem" will
2320 automatically be defined to hold the amount of
2321 remaining RAM in a form that can be passed as boot
2322 argument to Linux, for instance like that:
2324 setenv bootargs ... mem=\${mem}
2327 This way you can tell Linux not to use this memory,
2328 either, which results in a memory region that will
2329 not be affected by reboots.
2331 *WARNING* If your board configuration uses automatic
2332 detection of the RAM size, you must make sure that
2333 this memory test is non-destructive. So far, the
2334 following board configurations are known to be
2337 IVMS8, IVML24, SPD8xx,
2338 HERMES, IP860, RPXlite, LWMON,
2341 - Access to physical memory region (> 4GB)
2342 Some basic support is provided for operations on memory not
2343 normally accessible to U-Boot - e.g. some architectures
2344 support access to more than 4GB of memory on 32-bit
2345 machines using physical address extension or similar.
2346 Define CONFIG_PHYSMEM to access this basic support, which
2347 currently only supports clearing the memory.
2352 Define this variable to stop the system in case of a
2353 fatal error, so that you have to reset it manually.
2354 This is probably NOT a good idea for an embedded
2355 system where you want the system to reboot
2356 automatically as fast as possible, but it may be
2357 useful during development since you can try to debug
2358 the conditions that lead to the situation.
2360 CONFIG_NET_RETRY_COUNT
2362 This variable defines the number of retries for
2363 network operations like ARP, RARP, TFTP, or BOOTP
2364 before giving up the operation. If not defined, a
2365 default value of 5 is used.
2369 Timeout waiting for an ARP reply in milliseconds.
2373 Timeout in milliseconds used in NFS protocol.
2374 If you encounter "ERROR: Cannot umount" in nfs command,
2375 try longer timeout such as
2376 #define CONFIG_NFS_TIMEOUT 10000UL
2378 - Command Interpreter:
2379 CONFIG_AUTO_COMPLETE
2381 Enable auto completion of commands using TAB.
2383 CONFIG_SYS_PROMPT_HUSH_PS2
2385 This defines the secondary prompt string, which is
2386 printed when the command interpreter needs more input
2387 to complete a command. Usually "> ".
2391 In the current implementation, the local variables
2392 space and global environment variables space are
2393 separated. Local variables are those you define by
2394 simply typing `name=value'. To access a local
2395 variable later on, you have write `$name' or
2396 `${name}'; to execute the contents of a variable
2397 directly type `$name' at the command prompt.
2399 Global environment variables are those you use
2400 setenv/printenv to work with. To run a command stored
2401 in such a variable, you need to use the run command,
2402 and you must not use the '$' sign to access them.
2404 To store commands and special characters in a
2405 variable, please use double quotation marks
2406 surrounding the whole text of the variable, instead
2407 of the backslashes before semicolons and special
2410 - Command Line Editing and History:
2411 CONFIG_CMDLINE_EDITING
2413 Enable editing and History functions for interactive
2414 command line input operations
2416 - Command Line PS1/PS2 support:
2417 CONFIG_CMDLINE_PS_SUPPORT
2419 Enable support for changing the command prompt string
2420 at run-time. Only static string is supported so far.
2421 The string is obtained from environment variables PS1
2424 - Default Environment:
2425 CONFIG_EXTRA_ENV_SETTINGS
2427 Define this to contain any number of null terminated
2428 strings (variable = value pairs) that will be part of
2429 the default environment compiled into the boot image.
2431 For example, place something like this in your
2432 board's config file:
2434 #define CONFIG_EXTRA_ENV_SETTINGS \
2438 Warning: This method is based on knowledge about the
2439 internal format how the environment is stored by the
2440 U-Boot code. This is NOT an official, exported
2441 interface! Although it is unlikely that this format
2442 will change soon, there is no guarantee either.
2443 You better know what you are doing here.
2445 Note: overly (ab)use of the default environment is
2446 discouraged. Make sure to check other ways to preset
2447 the environment like the "source" command or the
2450 CONFIG_ENV_VARS_UBOOT_CONFIG
2452 Define this in order to add variables describing the
2453 U-Boot build configuration to the default environment.
2454 These will be named arch, cpu, board, vendor, and soc.
2456 Enabling this option will cause the following to be defined:
2464 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2466 Define this in order to add variables describing certain
2467 run-time determined information about the hardware to the
2468 environment. These will be named board_name, board_rev.
2470 CONFIG_DELAY_ENVIRONMENT
2472 Normally the environment is loaded when the board is
2473 initialised so that it is available to U-Boot. This inhibits
2474 that so that the environment is not available until
2475 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2476 this is instead controlled by the value of
2477 /config/load-environment.
2479 - DataFlash Support:
2480 CONFIG_HAS_DATAFLASH
2482 Defining this option enables DataFlash features and
2483 allows to read/write in Dataflash via the standard
2486 - Serial Flash support
2489 Defining this option enables SPI flash commands
2490 'sf probe/read/write/erase/update'.
2492 Usage requires an initial 'probe' to define the serial
2493 flash parameters, followed by read/write/erase/update
2496 The following defaults may be provided by the platform
2497 to handle the common case when only a single serial
2498 flash is present on the system.
2500 CONFIG_SF_DEFAULT_BUS Bus identifier
2501 CONFIG_SF_DEFAULT_CS Chip-select
2502 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2503 CONFIG_SF_DEFAULT_SPEED in Hz
2507 Define this option to include a destructive SPI flash
2510 - SystemACE Support:
2513 Adding this option adds support for Xilinx SystemACE
2514 chips attached via some sort of local bus. The address
2515 of the chip must also be defined in the
2516 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2518 #define CONFIG_SYSTEMACE
2519 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2521 When SystemACE support is added, the "ace" device type
2522 becomes available to the fat commands, i.e. fatls.
2524 - TFTP Fixed UDP Port:
2527 If this is defined, the environment variable tftpsrcp
2528 is used to supply the TFTP UDP source port value.
2529 If tftpsrcp isn't defined, the normal pseudo-random port
2530 number generator is used.
2532 Also, the environment variable tftpdstp is used to supply
2533 the TFTP UDP destination port value. If tftpdstp isn't
2534 defined, the normal port 69 is used.
2536 The purpose for tftpsrcp is to allow a TFTP server to
2537 blindly start the TFTP transfer using the pre-configured
2538 target IP address and UDP port. This has the effect of
2539 "punching through" the (Windows XP) firewall, allowing
2540 the remainder of the TFTP transfer to proceed normally.
2541 A better solution is to properly configure the firewall,
2542 but sometimes that is not allowed.
2544 - bootcount support:
2545 CONFIG_BOOTCOUNT_LIMIT
2547 This enables the bootcounter support, see:
2548 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2551 enable special bootcounter support on at91sam9xe based boards.
2553 enable special bootcounter support on da850 based boards.
2554 CONFIG_BOOTCOUNT_RAM
2555 enable support for the bootcounter in RAM
2556 CONFIG_BOOTCOUNT_I2C
2557 enable support for the bootcounter on an i2c (like RTC) device.
2558 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2559 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2561 CONFIG_BOOTCOUNT_ALEN = address len
2563 - Show boot progress:
2564 CONFIG_SHOW_BOOT_PROGRESS
2566 Defining this option allows to add some board-
2567 specific code (calling a user-provided function
2568 "show_boot_progress(int)") that enables you to show
2569 the system's boot progress on some display (for
2570 example, some LED's) on your board. At the moment,
2571 the following checkpoints are implemented:
2574 Legacy uImage format:
2577 1 common/cmd_bootm.c before attempting to boot an image
2578 -1 common/cmd_bootm.c Image header has bad magic number
2579 2 common/cmd_bootm.c Image header has correct magic number
2580 -2 common/cmd_bootm.c Image header has bad checksum
2581 3 common/cmd_bootm.c Image header has correct checksum
2582 -3 common/cmd_bootm.c Image data has bad checksum
2583 4 common/cmd_bootm.c Image data has correct checksum
2584 -4 common/cmd_bootm.c Image is for unsupported architecture
2585 5 common/cmd_bootm.c Architecture check OK
2586 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2587 6 common/cmd_bootm.c Image Type check OK
2588 -6 common/cmd_bootm.c gunzip uncompression error
2589 -7 common/cmd_bootm.c Unimplemented compression type
2590 7 common/cmd_bootm.c Uncompression OK
2591 8 common/cmd_bootm.c No uncompress/copy overwrite error
2592 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2594 9 common/image.c Start initial ramdisk verification
2595 -10 common/image.c Ramdisk header has bad magic number
2596 -11 common/image.c Ramdisk header has bad checksum
2597 10 common/image.c Ramdisk header is OK
2598 -12 common/image.c Ramdisk data has bad checksum
2599 11 common/image.c Ramdisk data has correct checksum
2600 12 common/image.c Ramdisk verification complete, start loading
2601 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2602 13 common/image.c Start multifile image verification
2603 14 common/image.c No initial ramdisk, no multifile, continue.
2605 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2607 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2608 -31 post/post.c POST test failed, detected by post_output_backlog()
2609 -32 post/post.c POST test failed, detected by post_run_single()
2611 34 common/cmd_doc.c before loading a Image from a DOC device
2612 -35 common/cmd_doc.c Bad usage of "doc" command
2613 35 common/cmd_doc.c correct usage of "doc" command
2614 -36 common/cmd_doc.c No boot device
2615 36 common/cmd_doc.c correct boot device
2616 -37 common/cmd_doc.c Unknown Chip ID on boot device
2617 37 common/cmd_doc.c correct chip ID found, device available
2618 -38 common/cmd_doc.c Read Error on boot device
2619 38 common/cmd_doc.c reading Image header from DOC device OK
2620 -39 common/cmd_doc.c Image header has bad magic number
2621 39 common/cmd_doc.c Image header has correct magic number
2622 -40 common/cmd_doc.c Error reading Image from DOC device
2623 40 common/cmd_doc.c Image header has correct magic number
2624 41 common/cmd_ide.c before loading a Image from a IDE device
2625 -42 common/cmd_ide.c Bad usage of "ide" command
2626 42 common/cmd_ide.c correct usage of "ide" command
2627 -43 common/cmd_ide.c No boot device
2628 43 common/cmd_ide.c boot device found
2629 -44 common/cmd_ide.c Device not available
2630 44 common/cmd_ide.c Device available
2631 -45 common/cmd_ide.c wrong partition selected
2632 45 common/cmd_ide.c partition selected
2633 -46 common/cmd_ide.c Unknown partition table
2634 46 common/cmd_ide.c valid partition table found
2635 -47 common/cmd_ide.c Invalid partition type
2636 47 common/cmd_ide.c correct partition type
2637 -48 common/cmd_ide.c Error reading Image Header on boot device
2638 48 common/cmd_ide.c reading Image Header from IDE device OK
2639 -49 common/cmd_ide.c Image header has bad magic number
2640 49 common/cmd_ide.c Image header has correct magic number
2641 -50 common/cmd_ide.c Image header has bad checksum
2642 50 common/cmd_ide.c Image header has correct checksum
2643 -51 common/cmd_ide.c Error reading Image from IDE device
2644 51 common/cmd_ide.c reading Image from IDE device OK
2645 52 common/cmd_nand.c before loading a Image from a NAND device
2646 -53 common/cmd_nand.c Bad usage of "nand" command
2647 53 common/cmd_nand.c correct usage of "nand" command
2648 -54 common/cmd_nand.c No boot device
2649 54 common/cmd_nand.c boot device found
2650 -55 common/cmd_nand.c Unknown Chip ID on boot device
2651 55 common/cmd_nand.c correct chip ID found, device available
2652 -56 common/cmd_nand.c Error reading Image Header on boot device
2653 56 common/cmd_nand.c reading Image Header from NAND device OK
2654 -57 common/cmd_nand.c Image header has bad magic number
2655 57 common/cmd_nand.c Image header has correct magic number
2656 -58 common/cmd_nand.c Error reading Image from NAND device
2657 58 common/cmd_nand.c reading Image from NAND device OK
2659 -60 common/env_common.c Environment has a bad CRC, using default
2661 64 net/eth.c starting with Ethernet configuration.
2662 -64 net/eth.c no Ethernet found.
2663 65 net/eth.c Ethernet found.
2665 -80 common/cmd_net.c usage wrong
2666 80 common/cmd_net.c before calling net_loop()
2667 -81 common/cmd_net.c some error in net_loop() occurred
2668 81 common/cmd_net.c net_loop() back without error
2669 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2670 82 common/cmd_net.c trying automatic boot
2671 83 common/cmd_net.c running "source" command
2672 -83 common/cmd_net.c some error in automatic boot or "source" command
2673 84 common/cmd_net.c end without errors
2678 100 common/cmd_bootm.c Kernel FIT Image has correct format
2679 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2680 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2681 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2682 102 common/cmd_bootm.c Kernel unit name specified
2683 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2684 103 common/cmd_bootm.c Found configuration node
2685 104 common/cmd_bootm.c Got kernel subimage node offset
2686 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2687 105 common/cmd_bootm.c Kernel subimage hash verification OK
2688 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2689 106 common/cmd_bootm.c Architecture check OK
2690 -106 common/cmd_bootm.c Kernel subimage has wrong type
2691 107 common/cmd_bootm.c Kernel subimage type OK
2692 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2693 108 common/cmd_bootm.c Got kernel subimage data/size
2694 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2695 -109 common/cmd_bootm.c Can't get kernel subimage type
2696 -110 common/cmd_bootm.c Can't get kernel subimage comp
2697 -111 common/cmd_bootm.c Can't get kernel subimage os
2698 -112 common/cmd_bootm.c Can't get kernel subimage load address
2699 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2701 120 common/image.c Start initial ramdisk verification
2702 -120 common/image.c Ramdisk FIT image has incorrect format
2703 121 common/image.c Ramdisk FIT image has correct format
2704 122 common/image.c No ramdisk subimage unit name, using configuration
2705 -122 common/image.c Can't get configuration for ramdisk subimage
2706 123 common/image.c Ramdisk unit name specified
2707 -124 common/image.c Can't get ramdisk subimage node offset
2708 125 common/image.c Got ramdisk subimage node offset
2709 -125 common/image.c Ramdisk subimage hash verification failed
2710 126 common/image.c Ramdisk subimage hash verification OK
2711 -126 common/image.c Ramdisk subimage for unsupported architecture
2712 127 common/image.c Architecture check OK
2713 -127 common/image.c Can't get ramdisk subimage data/size
2714 128 common/image.c Got ramdisk subimage data/size
2715 129 common/image.c Can't get ramdisk load address
2716 -129 common/image.c Got ramdisk load address
2718 -130 common/cmd_doc.c Incorrect FIT image format
2719 131 common/cmd_doc.c FIT image format OK
2721 -140 common/cmd_ide.c Incorrect FIT image format
2722 141 common/cmd_ide.c FIT image format OK
2724 -150 common/cmd_nand.c Incorrect FIT image format
2725 151 common/cmd_nand.c FIT image format OK
2727 - legacy image format:
2728 CONFIG_IMAGE_FORMAT_LEGACY
2729 enables the legacy image format support in U-Boot.
2732 enabled if CONFIG_FIT_SIGNATURE is not defined.
2734 CONFIG_DISABLE_IMAGE_LEGACY
2735 disable the legacy image format
2737 This define is introduced, as the legacy image format is
2738 enabled per default for backward compatibility.
2740 - Standalone program support:
2741 CONFIG_STANDALONE_LOAD_ADDR
2743 This option defines a board specific value for the
2744 address where standalone program gets loaded, thus
2745 overwriting the architecture dependent default
2748 - Frame Buffer Address:
2751 Define CONFIG_FB_ADDR if you want to use specific
2752 address for frame buffer. This is typically the case
2753 when using a graphics controller has separate video
2754 memory. U-Boot will then place the frame buffer at
2755 the given address instead of dynamically reserving it
2756 in system RAM by calling lcd_setmem(), which grabs
2757 the memory for the frame buffer depending on the
2758 configured panel size.
2760 Please see board_init_f function.
2762 - Automatic software updates via TFTP server
2764 CONFIG_UPDATE_TFTP_CNT_MAX
2765 CONFIG_UPDATE_TFTP_MSEC_MAX
2767 These options enable and control the auto-update feature;
2768 for a more detailed description refer to doc/README.update.
2770 - MTD Support (mtdparts command, UBI support)
2773 Adds the MTD device infrastructure from the Linux kernel.
2774 Needed for mtdparts command support.
2776 CONFIG_MTD_PARTITIONS
2778 Adds the MTD partitioning infrastructure from the Linux
2779 kernel. Needed for UBI support.
2782 CONFIG_UBI_SILENCE_MSG
2784 Make the verbose messages from UBI stop printing. This leaves
2785 warnings and errors enabled.
2788 CONFIG_MTD_UBI_WL_THRESHOLD
2789 This parameter defines the maximum difference between the highest
2790 erase counter value and the lowest erase counter value of eraseblocks
2791 of UBI devices. When this threshold is exceeded, UBI starts performing
2792 wear leveling by means of moving data from eraseblock with low erase
2793 counter to eraseblocks with high erase counter.
2795 The default value should be OK for SLC NAND flashes, NOR flashes and
2796 other flashes which have eraseblock life-cycle 100000 or more.
2797 However, in case of MLC NAND flashes which typically have eraseblock
2798 life-cycle less than 10000, the threshold should be lessened (e.g.,
2799 to 128 or 256, although it does not have to be power of 2).
2803 CONFIG_MTD_UBI_BEB_LIMIT
2804 This option specifies the maximum bad physical eraseblocks UBI
2805 expects on the MTD device (per 1024 eraseblocks). If the
2806 underlying flash does not admit of bad eraseblocks (e.g. NOR
2807 flash), this value is ignored.
2809 NAND datasheets often specify the minimum and maximum NVM
2810 (Number of Valid Blocks) for the flashes' endurance lifetime.
2811 The maximum expected bad eraseblocks per 1024 eraseblocks
2812 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2813 which gives 20 for most NANDs (MaxNVB is basically the total
2814 count of eraseblocks on the chip).
2816 To put it differently, if this value is 20, UBI will try to
2817 reserve about 1.9% of physical eraseblocks for bad blocks
2818 handling. And that will be 1.9% of eraseblocks on the entire
2819 NAND chip, not just the MTD partition UBI attaches. This means
2820 that if you have, say, a NAND flash chip admits maximum 40 bad
2821 eraseblocks, and it is split on two MTD partitions of the same
2822 size, UBI will reserve 40 eraseblocks when attaching a
2827 CONFIG_MTD_UBI_FASTMAP
2828 Fastmap is a mechanism which allows attaching an UBI device
2829 in nearly constant time. Instead of scanning the whole MTD device it
2830 only has to locate a checkpoint (called fastmap) on the device.
2831 The on-flash fastmap contains all information needed to attach
2832 the device. Using fastmap makes only sense on large devices where
2833 attaching by scanning takes long. UBI will not automatically install
2834 a fastmap on old images, but you can set the UBI parameter
2835 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2836 that fastmap-enabled images are still usable with UBI implementations
2837 without fastmap support. On typical flash devices the whole fastmap
2838 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2840 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2841 Set this parameter to enable fastmap automatically on images
2845 CONFIG_MTD_UBI_FM_DEBUG
2846 Enable UBI fastmap debug
2850 CONFIG_UBIFS_SILENCE_MSG
2852 Make the verbose messages from UBIFS stop printing. This leaves
2853 warnings and errors enabled.
2857 Enable building of SPL globally.
2860 LDSCRIPT for linking the SPL binary.
2862 CONFIG_SPL_MAX_FOOTPRINT
2863 Maximum size in memory allocated to the SPL, BSS included.
2864 When defined, the linker checks that the actual memory
2865 used by SPL from _start to __bss_end does not exceed it.
2866 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2867 must not be both defined at the same time.
2870 Maximum size of the SPL image (text, data, rodata, and
2871 linker lists sections), BSS excluded.
2872 When defined, the linker checks that the actual size does
2875 CONFIG_SPL_TEXT_BASE
2876 TEXT_BASE for linking the SPL binary.
2878 CONFIG_SPL_RELOC_TEXT_BASE
2879 Address to relocate to. If unspecified, this is equal to
2880 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2882 CONFIG_SPL_BSS_START_ADDR
2883 Link address for the BSS within the SPL binary.
2885 CONFIG_SPL_BSS_MAX_SIZE
2886 Maximum size in memory allocated to the SPL BSS.
2887 When defined, the linker checks that the actual memory used
2888 by SPL from __bss_start to __bss_end does not exceed it.
2889 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2890 must not be both defined at the same time.
2893 Adress of the start of the stack SPL will use
2895 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2896 When defined, SPL will panic() if the image it has
2897 loaded does not have a signature.
2898 Defining this is useful when code which loads images
2899 in SPL cannot guarantee that absolutely all read errors
2901 An example is the LPC32XX MLC NAND driver, which will
2902 consider that a completely unreadable NAND block is bad,
2903 and thus should be skipped silently.
2905 CONFIG_SPL_RELOC_STACK
2906 Adress of the start of the stack SPL will use after
2907 relocation. If unspecified, this is equal to
2910 CONFIG_SYS_SPL_MALLOC_START
2911 Starting address of the malloc pool used in SPL.
2912 When this option is set the full malloc is used in SPL and
2913 it is set up by spl_init() and before that, the simple malloc()
2914 can be used if CONFIG_SYS_MALLOC_F is defined.
2916 CONFIG_SYS_SPL_MALLOC_SIZE
2917 The size of the malloc pool used in SPL.
2919 CONFIG_SPL_FRAMEWORK
2920 Enable the SPL framework under common/. This framework
2921 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2922 NAND loading of the Linux Kernel.
2925 Enable booting directly to an OS from SPL.
2926 See also: doc/README.falcon
2928 CONFIG_SPL_DISPLAY_PRINT
2929 For ARM, enable an optional function to print more information
2930 about the running system.
2932 CONFIG_SPL_INIT_MINIMAL
2933 Arch init code should be built for a very small image
2935 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2936 Partition on the MMC to load U-Boot from when the MMC is being
2939 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2940 Sector to load kernel uImage from when MMC is being
2941 used in raw mode (for Falcon mode)
2943 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2944 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2945 Sector and number of sectors to load kernel argument
2946 parameters from when MMC is being used in raw mode
2949 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2950 Partition on the MMC to load U-Boot from when the MMC is being
2953 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2954 Filename to read to load U-Boot when reading from filesystem
2956 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2957 Filename to read to load kernel uImage when reading
2958 from filesystem (for Falcon mode)
2960 CONFIG_SPL_FS_LOAD_ARGS_NAME
2961 Filename to read to load kernel argument parameters
2962 when reading from filesystem (for Falcon mode)
2964 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2965 Set this for NAND SPL on PPC mpc83xx targets, so that
2966 start.S waits for the rest of the SPL to load before
2967 continuing (the hardware starts execution after just
2968 loading the first page rather than the full 4K).
2970 CONFIG_SPL_SKIP_RELOCATE
2971 Avoid SPL relocation
2973 CONFIG_SPL_NAND_BASE
2974 Include nand_base.c in the SPL. Requires
2975 CONFIG_SPL_NAND_DRIVERS.
2977 CONFIG_SPL_NAND_DRIVERS
2978 SPL uses normal NAND drivers, not minimal drivers.
2981 Include standard software ECC in the SPL
2983 CONFIG_SPL_NAND_SIMPLE
2984 Support for NAND boot using simple NAND drivers that
2985 expose the cmd_ctrl() interface.
2988 Support for a lightweight UBI (fastmap) scanner and
2991 CONFIG_SPL_NAND_RAW_ONLY
2992 Support to boot only raw u-boot.bin images. Use this only
2993 if you need to save space.
2995 CONFIG_SPL_COMMON_INIT_DDR
2996 Set for common ddr init with serial presence detect in
2999 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3000 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3001 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3002 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3003 CONFIG_SYS_NAND_ECCBYTES
3004 Defines the size and behavior of the NAND that SPL uses
3007 CONFIG_SPL_NAND_BOOT
3008 Add support NAND boot
3010 CONFIG_SYS_NAND_U_BOOT_OFFS
3011 Location in NAND to read U-Boot from
3013 CONFIG_SYS_NAND_U_BOOT_DST
3014 Location in memory to load U-Boot to
3016 CONFIG_SYS_NAND_U_BOOT_SIZE
3017 Size of image to load
3019 CONFIG_SYS_NAND_U_BOOT_START
3020 Entry point in loaded image to jump to
3022 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3023 Define this if you need to first read the OOB and then the
3024 data. This is used, for example, on davinci platforms.
3026 CONFIG_SPL_OMAP3_ID_NAND
3027 Support for an OMAP3-specific set of functions to return the
3028 ID and MFR of the first attached NAND chip, if present.
3030 CONFIG_SPL_RAM_DEVICE
3031 Support for running image already present in ram, in SPL binary
3034 Image offset to which the SPL should be padded before appending
3035 the SPL payload. By default, this is defined as
3036 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3037 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3038 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3041 Final target image containing SPL and payload. Some SPLs
3042 use an arch-specific makefile fragment instead, for
3043 example if more than one image needs to be produced.
3045 CONFIG_FIT_SPL_PRINT
3046 Printing information about a FIT image adds quite a bit of
3047 code to SPL. So this is normally disabled in SPL. Use this
3048 option to re-enable it. This will affect the output of the
3049 bootm command when booting a FIT image.
3053 Enable building of TPL globally.
3056 Image offset to which the TPL should be padded before appending
3057 the TPL payload. By default, this is defined as
3058 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3059 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3060 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3062 - Interrupt support (PPC):
3064 There are common interrupt_init() and timer_interrupt()
3065 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3066 for CPU specific initialization. interrupt_init_cpu()
3067 should set decrementer_count to appropriate value. If
3068 CPU resets decrementer automatically after interrupt
3069 (ppc4xx) it should set decrementer_count to zero.
3070 timer_interrupt() calls timer_interrupt_cpu() for CPU
3071 specific handling. If board has watchdog / status_led
3072 / other_activity_monitor it works automatically from
3073 general timer_interrupt().
3076 Board initialization settings:
3077 ------------------------------
3079 During Initialization u-boot calls a number of board specific functions
3080 to allow the preparation of board specific prerequisites, e.g. pin setup
3081 before drivers are initialized. To enable these callbacks the
3082 following configuration macros have to be defined. Currently this is
3083 architecture specific, so please check arch/your_architecture/lib/board.c
3084 typically in board_init_f() and board_init_r().
3086 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3087 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3088 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3089 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3091 Configuration Settings:
3092 -----------------------
3094 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3095 Optionally it can be defined to support 64-bit memory commands.
3097 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3098 undefine this when you're short of memory.
3100 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3101 width of the commands listed in the 'help' command output.
3103 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3104 prompt for user input.
3106 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3108 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3110 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3112 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3113 the application (usually a Linux kernel) when it is
3116 - CONFIG_SYS_BAUDRATE_TABLE:
3117 List of legal baudrate settings for this board.
3119 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3120 Begin and End addresses of the area used by the
3123 - CONFIG_SYS_ALT_MEMTEST:
3124 Enable an alternate, more extensive memory test.
3126 - CONFIG_SYS_MEMTEST_SCRATCH:
3127 Scratch address used by the alternate memory test
3128 You only need to set this if address zero isn't writeable
3130 - CONFIG_SYS_MEM_RESERVE_SECURE
3131 Only implemented for ARMv8 for now.
3132 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3133 is substracted from total RAM and won't be reported to OS.
3134 This memory can be used as secure memory. A variable
3135 gd->arch.secure_ram is used to track the location. In systems
3136 the RAM base is not zero, or RAM is divided into banks,
3137 this variable needs to be recalcuated to get the address.
3139 - CONFIG_SYS_MEM_TOP_HIDE:
3140 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3141 this specified memory area will get subtracted from the top
3142 (end) of RAM and won't get "touched" at all by U-Boot. By
3143 fixing up gd->ram_size the Linux kernel should gets passed
3144 the now "corrected" memory size and won't touch it either.
3145 This should work for arch/ppc and arch/powerpc. Only Linux
3146 board ports in arch/powerpc with bootwrapper support that
3147 recalculate the memory size from the SDRAM controller setup
3148 will have to get fixed in Linux additionally.
3150 This option can be used as a workaround for the 440EPx/GRx
3151 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3154 WARNING: Please make sure that this value is a multiple of
3155 the Linux page size (normally 4k). If this is not the case,
3156 then the end address of the Linux memory will be located at a
3157 non page size aligned address and this could cause major
3160 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3161 Enable temporary baudrate change while serial download
3163 - CONFIG_SYS_SDRAM_BASE:
3164 Physical start address of SDRAM. _Must_ be 0 here.
3166 - CONFIG_SYS_FLASH_BASE:
3167 Physical start address of Flash memory.
3169 - CONFIG_SYS_MONITOR_BASE:
3170 Physical start address of boot monitor code (set by
3171 make config files to be same as the text base address
3172 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3173 CONFIG_SYS_FLASH_BASE when booting from flash.
3175 - CONFIG_SYS_MONITOR_LEN:
3176 Size of memory reserved for monitor code, used to
3177 determine _at_compile_time_ (!) if the environment is
3178 embedded within the U-Boot image, or in a separate
3181 - CONFIG_SYS_MALLOC_LEN:
3182 Size of DRAM reserved for malloc() use.
3184 - CONFIG_SYS_MALLOC_F_LEN
3185 Size of the malloc() pool for use before relocation. If
3186 this is defined, then a very simple malloc() implementation
3187 will become available before relocation. The address is just
3188 below the global data, and the stack is moved down to make
3191 This feature allocates regions with increasing addresses
3192 within the region. calloc() is supported, but realloc()
3193 is not available. free() is supported but does nothing.
3194 The memory will be freed (or in fact just forgotten) when
3195 U-Boot relocates itself.
3197 - CONFIG_SYS_MALLOC_SIMPLE
3198 Provides a simple and small malloc() and calloc() for those
3199 boards which do not use the full malloc in SPL (which is
3200 enabled with CONFIG_SYS_SPL_MALLOC_START).
3202 - CONFIG_SYS_NONCACHED_MEMORY:
3203 Size of non-cached memory area. This area of memory will be
3204 typically located right below the malloc() area and mapped
3205 uncached in the MMU. This is useful for drivers that would
3206 otherwise require a lot of explicit cache maintenance. For
3207 some drivers it's also impossible to properly maintain the
3208 cache. For example if the regions that need to be flushed
3209 are not a multiple of the cache-line size, *and* padding
3210 cannot be allocated between the regions to align them (i.e.
3211 if the HW requires a contiguous array of regions, and the
3212 size of each region is not cache-aligned), then a flush of
3213 one region may result in overwriting data that hardware has
3214 written to another region in the same cache-line. This can
3215 happen for example in network drivers where descriptors for
3216 buffers are typically smaller than the CPU cache-line (e.g.
3217 16 bytes vs. 32 or 64 bytes).
3219 Non-cached memory is only supported on 32-bit ARM at present.
3221 - CONFIG_SYS_BOOTM_LEN:
3222 Normally compressed uImages are limited to an
3223 uncompressed size of 8 MBytes. If this is not enough,
3224 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3225 to adjust this setting to your needs.
3227 - CONFIG_SYS_BOOTMAPSZ:
3228 Maximum size of memory mapped by the startup code of
3229 the Linux kernel; all data that must be processed by
3230 the Linux kernel (bd_info, boot arguments, FDT blob if
3231 used) must be put below this limit, unless "bootm_low"
3232 environment variable is defined and non-zero. In such case
3233 all data for the Linux kernel must be between "bootm_low"
3234 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3235 variable "bootm_mapsize" will override the value of
3236 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3237 then the value in "bootm_size" will be used instead.
3239 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3240 Enable initrd_high functionality. If defined then the
3241 initrd_high feature is enabled and the bootm ramdisk subcommand
3244 - CONFIG_SYS_BOOT_GET_CMDLINE:
3245 Enables allocating and saving kernel cmdline in space between
3246 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3248 - CONFIG_SYS_BOOT_GET_KBD:
3249 Enables allocating and saving a kernel copy of the bd_info in
3250 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3252 - CONFIG_SYS_MAX_FLASH_BANKS:
3253 Max number of Flash memory banks
3255 - CONFIG_SYS_MAX_FLASH_SECT:
3256 Max number of sectors on a Flash chip
3258 - CONFIG_SYS_FLASH_ERASE_TOUT:
3259 Timeout for Flash erase operations (in ms)
3261 - CONFIG_SYS_FLASH_WRITE_TOUT:
3262 Timeout for Flash write operations (in ms)
3264 - CONFIG_SYS_FLASH_LOCK_TOUT
3265 Timeout for Flash set sector lock bit operation (in ms)
3267 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3268 Timeout for Flash clear lock bits operation (in ms)
3270 - CONFIG_SYS_FLASH_PROTECTION
3271 If defined, hardware flash sectors protection is used
3272 instead of U-Boot software protection.
3274 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3276 Enable TFTP transfers directly to flash memory;
3277 without this option such a download has to be
3278 performed in two steps: (1) download to RAM, and (2)
3279 copy from RAM to flash.
3281 The two-step approach is usually more reliable, since
3282 you can check if the download worked before you erase
3283 the flash, but in some situations (when system RAM is
3284 too limited to allow for a temporary copy of the
3285 downloaded image) this option may be very useful.
3287 - CONFIG_SYS_FLASH_CFI:
3288 Define if the flash driver uses extra elements in the
3289 common flash structure for storing flash geometry.
3291 - CONFIG_FLASH_CFI_DRIVER
3292 This option also enables the building of the cfi_flash driver
3293 in the drivers directory
3295 - CONFIG_FLASH_CFI_MTD
3296 This option enables the building of the cfi_mtd driver
3297 in the drivers directory. The driver exports CFI flash
3300 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3301 Use buffered writes to flash.
3303 - CONFIG_FLASH_SPANSION_S29WS_N
3304 s29ws-n MirrorBit flash has non-standard addresses for buffered
3307 - CONFIG_SYS_FLASH_QUIET_TEST
3308 If this option is defined, the common CFI flash doesn't
3309 print it's warning upon not recognized FLASH banks. This
3310 is useful, if some of the configured banks are only
3311 optionally available.
3313 - CONFIG_FLASH_SHOW_PROGRESS
3314 If defined (must be an integer), print out countdown
3315 digits and dots. Recommended value: 45 (9..1) for 80
3316 column displays, 15 (3..1) for 40 column displays.
3318 - CONFIG_FLASH_VERIFY
3319 If defined, the content of the flash (destination) is compared
3320 against the source after the write operation. An error message
3321 will be printed when the contents are not identical.
3322 Please note that this option is useless in nearly all cases,
3323 since such flash programming errors usually are detected earlier
3324 while unprotecting/erasing/programming. Please only enable
3325 this option if you really know what you are doing.
3327 - CONFIG_SYS_RX_ETH_BUFFER:
3328 Defines the number of Ethernet receive buffers. On some
3329 Ethernet controllers it is recommended to set this value
3330 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3331 buffers can be full shortly after enabling the interface
3332 on high Ethernet traffic.
3333 Defaults to 4 if not defined.
3335 - CONFIG_ENV_MAX_ENTRIES
3337 Maximum number of entries in the hash table that is used
3338 internally to store the environment settings. The default
3339 setting is supposed to be generous and should work in most
3340 cases. This setting can be used to tune behaviour; see
3341 lib/hashtable.c for details.
3343 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3344 - CONFIG_ENV_FLAGS_LIST_STATIC
3345 Enable validation of the values given to environment variables when
3346 calling env set. Variables can be restricted to only decimal,
3347 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3348 the variables can also be restricted to IP address or MAC address.
3350 The format of the list is:
3351 type_attribute = [s|d|x|b|i|m]
3352 access_attribute = [a|r|o|c]
3353 attributes = type_attribute[access_attribute]
3354 entry = variable_name[:attributes]
3357 The type attributes are:
3358 s - String (default)
3361 b - Boolean ([1yYtT|0nNfF])
3365 The access attributes are:
3371 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3372 Define this to a list (string) to define the ".flags"
3373 environment variable in the default or embedded environment.
3375 - CONFIG_ENV_FLAGS_LIST_STATIC
3376 Define this to a list (string) to define validation that
3377 should be done if an entry is not found in the ".flags"
3378 environment variable. To override a setting in the static
3379 list, simply add an entry for the same variable name to the
3382 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3383 regular expression. This allows multiple variables to define the same
3384 flags without explicitly listing them for each variable.
3386 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3387 If defined, don't allow the -f switch to env set override variable
3391 If stdint.h is available with your toolchain you can define this
3392 option to enable it. You can provide option 'USE_STDINT=1' when
3393 building U-Boot to enable this.
3395 The following definitions that deal with the placement and management
3396 of environment data (variable area); in general, we support the
3397 following configurations:
3399 - CONFIG_BUILD_ENVCRC:
3401 Builds up envcrc with the target environment so that external utils
3402 may easily extract it and embed it in final U-Boot images.
3404 BE CAREFUL! The first access to the environment happens quite early
3405 in U-Boot initialization (when we try to get the setting of for the
3406 console baudrate). You *MUST* have mapped your NVRAM area then, or
3409 Please note that even with NVRAM we still use a copy of the
3410 environment in RAM: we could work on NVRAM directly, but we want to
3411 keep settings there always unmodified except somebody uses "saveenv"
3412 to save the current settings.
3414 BE CAREFUL! For some special cases, the local device can not use
3415 "saveenv" command. For example, the local device will get the
3416 environment stored in a remote NOR flash by SRIO or PCIE link,
3417 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3419 - CONFIG_NAND_ENV_DST
3421 Defines address in RAM to which the nand_spl code should copy the
3422 environment. If redundant environment is used, it will be copied to
3423 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3425 Please note that the environment is read-only until the monitor
3426 has been relocated to RAM and a RAM copy of the environment has been
3427 created; also, when using EEPROM you will have to use getenv_f()
3428 until then to read environment variables.
3430 The environment is protected by a CRC32 checksum. Before the monitor
3431 is relocated into RAM, as a result of a bad CRC you will be working
3432 with the compiled-in default environment - *silently*!!! [This is
3433 necessary, because the first environment variable we need is the
3434 "baudrate" setting for the console - if we have a bad CRC, we don't
3435 have any device yet where we could complain.]
3437 Note: once the monitor has been relocated, then it will complain if
3438 the default environment is used; a new CRC is computed as soon as you
3439 use the "saveenv" command to store a valid environment.
3441 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3442 Echo the inverted Ethernet link state to the fault LED.
3444 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3445 also needs to be defined.
3447 - CONFIG_SYS_FAULT_MII_ADDR:
3448 MII address of the PHY to check for the Ethernet link state.
3450 - CONFIG_NS16550_MIN_FUNCTIONS:
3451 Define this if you desire to only have use of the NS16550_init
3452 and NS16550_putc functions for the serial driver located at
3453 drivers/serial/ns16550.c. This option is useful for saving
3454 space for already greatly restricted images, including but not
3455 limited to NAND_SPL configurations.
3457 - CONFIG_DISPLAY_BOARDINFO
3458 Display information about the board that U-Boot is running on
3459 when U-Boot starts up. The board function checkboard() is called
3462 - CONFIG_DISPLAY_BOARDINFO_LATE
3463 Similar to the previous option, but display this information
3464 later, once stdio is running and output goes to the LCD, if
3467 - CONFIG_BOARD_SIZE_LIMIT:
3468 Maximum size of the U-Boot image. When defined, the
3469 build system checks that the actual size does not
3472 Low Level (hardware related) configuration options:
3473 ---------------------------------------------------
3475 - CONFIG_SYS_CACHELINE_SIZE:
3476 Cache Line Size of the CPU.
3478 - CONFIG_SYS_CCSRBAR_DEFAULT:
3479 Default (power-on reset) physical address of CCSR on Freescale
3482 - CONFIG_SYS_CCSRBAR:
3483 Virtual address of CCSR. On a 32-bit build, this is typically
3484 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3486 - CONFIG_SYS_CCSRBAR_PHYS:
3487 Physical address of CCSR. CCSR can be relocated to a new
3488 physical address, if desired. In this case, this macro should
3489 be set to that address. Otherwise, it should be set to the
3490 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3491 is typically relocated on 36-bit builds. It is recommended
3492 that this macro be defined via the _HIGH and _LOW macros:
3494 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3495 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3497 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3498 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3499 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3500 used in assembly code, so it must not contain typecasts or
3501 integer size suffixes (e.g. "ULL").
3503 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3504 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3505 used in assembly code, so it must not contain typecasts or
3506 integer size suffixes (e.g. "ULL").
3508 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3509 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3510 forced to a value that ensures that CCSR is not relocated.
3512 - Floppy Disk Support:
3513 CONFIG_SYS_FDC_DRIVE_NUMBER
3515 the default drive number (default value 0)
3517 CONFIG_SYS_ISA_IO_STRIDE
3519 defines the spacing between FDC chipset registers
3522 CONFIG_SYS_ISA_IO_OFFSET
3524 defines the offset of register from address. It
3525 depends on which part of the data bus is connected to
3526 the FDC chipset. (default value 0)
3528 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3529 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3532 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3533 fdc_hw_init() is called at the beginning of the FDC
3534 setup. fdc_hw_init() must be provided by the board
3535 source code. It is used to make hardware-dependent
3539 Most IDE controllers were designed to be connected with PCI
3540 interface. Only few of them were designed for AHB interface.
3541 When software is doing ATA command and data transfer to
3542 IDE devices through IDE-AHB controller, some additional
3543 registers accessing to these kind of IDE-AHB controller
3546 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3547 DO NOT CHANGE unless you know exactly what you're
3548 doing! (11-4) [MPC8xx systems only]
3550 - CONFIG_SYS_INIT_RAM_ADDR:
3552 Start address of memory area that can be used for
3553 initial data and stack; please note that this must be
3554 writable memory that is working WITHOUT special
3555 initialization, i. e. you CANNOT use normal RAM which
3556 will become available only after programming the
3557 memory controller and running certain initialization
3560 U-Boot uses the following memory types:
3561 - MPC8xx: IMMR (internal memory of the CPU)
3563 - CONFIG_SYS_GBL_DATA_OFFSET:
3565 Offset of the initial data structure in the memory
3566 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3567 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3568 data is located at the end of the available space
3569 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3570 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3571 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3572 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3575 On the MPC824X (or other systems that use the data
3576 cache for initial memory) the address chosen for
3577 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3578 point to an otherwise UNUSED address space between
3579 the top of RAM and the start of the PCI space.
3581 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3583 - CONFIG_SYS_OR_TIMING_SDRAM:
3586 - CONFIG_SYS_MAMR_PTA:
3587 periodic timer for refresh
3589 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3590 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3591 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3592 CONFIG_SYS_BR1_PRELIM:
3593 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3595 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3596 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3597 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3598 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3600 - CONFIG_PCI_ENUM_ONLY
3601 Only scan through and get the devices on the buses.
3602 Don't do any setup work, presumably because someone or
3603 something has already done it, and we don't need to do it
3604 a second time. Useful for platforms that are pre-booted
3605 by coreboot or similar.
3607 - CONFIG_PCI_INDIRECT_BRIDGE:
3608 Enable support for indirect PCI bridges.
3611 Chip has SRIO or not
3614 Board has SRIO 1 port available
3617 Board has SRIO 2 port available
3619 - CONFIG_SRIO_PCIE_BOOT_MASTER
3620 Board can support master function for Boot from SRIO and PCIE
3622 - CONFIG_SYS_SRIOn_MEM_VIRT:
3623 Virtual Address of SRIO port 'n' memory region
3625 - CONFIG_SYS_SRIOn_MEM_PHYS:
3626 Physical Address of SRIO port 'n' memory region
3628 - CONFIG_SYS_SRIOn_MEM_SIZE:
3629 Size of SRIO port 'n' memory region
3631 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3632 Defined to tell the NAND controller that the NAND chip is using
3634 Not all NAND drivers use this symbol.
3635 Example of drivers that use it:
3636 - drivers/mtd/nand/ndfc.c
3637 - drivers/mtd/nand/mxc_nand.c
3639 - CONFIG_SYS_NDFC_EBC0_CFG
3640 Sets the EBC0_CFG register for the NDFC. If not defined
3641 a default value will be used.
3644 Get DDR timing information from an I2C EEPROM. Common
3645 with pluggable memory modules such as SODIMMs
3648 I2C address of the SPD EEPROM
3650 - CONFIG_SYS_SPD_BUS_NUM
3651 If SPD EEPROM is on an I2C bus other than the first
3652 one, specify here. Note that the value must resolve
3653 to something your driver can deal with.
3655 - CONFIG_SYS_DDR_RAW_TIMING
3656 Get DDR timing information from other than SPD. Common with
3657 soldered DDR chips onboard without SPD. DDR raw timing
3658 parameters are extracted from datasheet and hard-coded into
3659 header files or board specific files.
3661 - CONFIG_FSL_DDR_INTERACTIVE
3662 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3664 - CONFIG_FSL_DDR_SYNC_REFRESH
3665 Enable sync of refresh for multiple controllers.
3667 - CONFIG_FSL_DDR_BIST
3668 Enable built-in memory test for Freescale DDR controllers.
3670 - CONFIG_SYS_83XX_DDR_USES_CS0
3671 Only for 83xx systems. If specified, then DDR should
3672 be configured using CS0 and CS1 instead of CS2 and CS3.
3675 Enable RMII mode for all FECs.
3676 Note that this is a global option, we can't
3677 have one FEC in standard MII mode and another in RMII mode.
3679 - CONFIG_CRC32_VERIFY
3680 Add a verify option to the crc32 command.
3683 => crc32 -v <address> <count> <crc32>
3685 Where address/count indicate a memory area
3686 and crc32 is the correct crc32 which the
3690 Add the "loopw" memory command. This only takes effect if
3691 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3694 Add the "mdc" and "mwc" memory commands. These are cyclic
3699 This command will print 4 bytes (10,11,12,13) each 500 ms.
3701 => mwc.l 100 12345678 10
3702 This command will write 12345678 to address 100 all 10 ms.
3704 This only takes effect if the memory commands are activated
3705 globally (CONFIG_CMD_MEMORY).
3707 - CONFIG_SKIP_LOWLEVEL_INIT
3708 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3709 low level initializations (like setting up the memory
3710 controller) are omitted and/or U-Boot does not
3711 relocate itself into RAM.
3713 Normally this variable MUST NOT be defined. The only
3714 exception is when U-Boot is loaded (to RAM) by some
3715 other boot loader or by a debugger which performs
3716 these initializations itself.
3718 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3719 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3720 to be skipped. The normal CP15 init (such as enabling the
3721 instruction cache) is still performed.
3724 Modifies the behaviour of start.S when compiling a loader
3725 that is executed before the actual U-Boot. E.g. when
3726 compiling a NAND SPL.
3729 Modifies the behaviour of start.S when compiling a loader
3730 that is executed after the SPL and before the actual U-Boot.
3731 It is loaded by the SPL.
3733 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3734 Only for 85xx systems. If this variable is specified, the section
3735 .resetvec is not kept and the section .bootpg is placed in the
3736 previous 4k of the .text section.
3738 - CONFIG_ARCH_MAP_SYSMEM
3739 Generally U-Boot (and in particular the md command) uses
3740 effective address. It is therefore not necessary to regard
3741 U-Boot address as virtual addresses that need to be translated
3742 to physical addresses. However, sandbox requires this, since
3743 it maintains its own little RAM buffer which contains all
3744 addressable memory. This option causes some memory accesses
3745 to be mapped through map_sysmem() / unmap_sysmem().
3747 - CONFIG_X86_RESET_VECTOR
3748 If defined, the x86 reset vector code is included. This is not
3749 needed when U-Boot is running from Coreboot.
3751 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3752 Enables the RTC32K OSC on AM33xx based plattforms
3754 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3755 Option to disable subpage write in NAND driver
3756 driver that uses this:
3757 drivers/mtd/nand/davinci_nand.c
3759 Freescale QE/FMAN Firmware Support:
3760 -----------------------------------
3762 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3763 loading of "firmware", which is encoded in the QE firmware binary format.
3764 This firmware often needs to be loaded during U-Boot booting, so macros
3765 are used to identify the storage device (NOR flash, SPI, etc) and the address
3768 - CONFIG_SYS_FMAN_FW_ADDR
3769 The address in the storage device where the FMAN microcode is located. The
3770 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3773 - CONFIG_SYS_QE_FW_ADDR
3774 The address in the storage device where the QE microcode is located. The
3775 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3778 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3779 The maximum possible size of the firmware. The firmware binary format
3780 has a field that specifies the actual size of the firmware, but it
3781 might not be possible to read any part of the firmware unless some
3782 local storage is allocated to hold the entire firmware first.
3784 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3785 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3786 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3787 virtual address in NOR flash.
3789 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3790 Specifies that QE/FMAN firmware is located in NAND flash.
3791 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3793 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3794 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3795 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3797 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3798 Specifies that QE/FMAN firmware is located in the remote (master)
3799 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3800 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3801 window->master inbound window->master LAW->the ucode address in
3802 master's memory space.
3804 Freescale Layerscape Management Complex Firmware Support:
3805 ---------------------------------------------------------
3806 The Freescale Layerscape Management Complex (MC) supports the loading of
3808 This firmware often needs to be loaded during U-Boot booting, so macros
3809 are used to identify the storage device (NOR flash, SPI, etc) and the address
3812 - CONFIG_FSL_MC_ENET
3813 Enable the MC driver for Layerscape SoCs.
3815 Freescale Layerscape Debug Server Support:
3816 -------------------------------------------
3817 The Freescale Layerscape Debug Server Support supports the loading of
3818 "Debug Server firmware" and triggering SP boot-rom.
3819 This firmware often needs to be loaded during U-Boot booting.
3821 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3822 Define alignment of reserved memory MC requires
3827 In order to achieve reproducible builds, timestamps used in the U-Boot build
3828 process have to be set to a fixed value.
3830 This is done using the SOURCE_DATE_EPOCH environment variable.
3831 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3832 option for U-Boot or an environment variable in U-Boot.
3834 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3836 Building the Software:
3837 ======================
3839 Building U-Boot has been tested in several native build environments
3840 and in many different cross environments. Of course we cannot support
3841 all possibly existing versions of cross development tools in all
3842 (potentially obsolete) versions. In case of tool chain problems we
3843 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3844 which is extensively used to build and test U-Boot.
3846 If you are not using a native environment, it is assumed that you
3847 have GNU cross compiling tools available in your path. In this case,
3848 you must set the environment variable CROSS_COMPILE in your shell.
3849 Note that no changes to the Makefile or any other source files are
3850 necessary. For example using the ELDK on a 4xx CPU, please enter:
3852 $ CROSS_COMPILE=ppc_4xx-
3853 $ export CROSS_COMPILE
3855 Note: If you wish to generate Windows versions of the utilities in
3856 the tools directory you can use the MinGW toolchain
3857 (http://www.mingw.org). Set your HOST tools to the MinGW
3858 toolchain and execute 'make tools'. For example:
3860 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3862 Binaries such as tools/mkimage.exe will be created which can
3863 be executed on computers running Windows.
3865 U-Boot is intended to be simple to build. After installing the
3866 sources you must configure U-Boot for one specific board type. This
3871 where "NAME_defconfig" is the name of one of the existing configu-
3872 rations; see boards.cfg for supported names.
3874 Note: for some board special configuration names may exist; check if
3875 additional information is available from the board vendor; for
3876 instance, the TQM823L systems are available without (standard)
3877 or with LCD support. You can select such additional "features"
3878 when choosing the configuration, i. e.
3880 make TQM823L_defconfig
3881 - will configure for a plain TQM823L, i. e. no LCD support
3883 make TQM823L_LCD_defconfig
3884 - will configure for a TQM823L with U-Boot console on LCD
3889 Finally, type "make all", and you should get some working U-Boot
3890 images ready for download to / installation on your system:
3892 - "u-boot.bin" is a raw binary image
3893 - "u-boot" is an image in ELF binary format
3894 - "u-boot.srec" is in Motorola S-Record format
3896 By default the build is performed locally and the objects are saved
3897 in the source directory. One of the two methods can be used to change
3898 this behavior and build U-Boot to some external directory:
3900 1. Add O= to the make command line invocations:
3902 make O=/tmp/build distclean
3903 make O=/tmp/build NAME_defconfig
3904 make O=/tmp/build all
3906 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3908 export KBUILD_OUTPUT=/tmp/build
3913 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3917 Please be aware that the Makefiles assume you are using GNU make, so
3918 for instance on NetBSD you might need to use "gmake" instead of
3922 If the system board that you have is not listed, then you will need
3923 to port U-Boot to your hardware platform. To do this, follow these
3926 1. Create a new directory to hold your board specific code. Add any
3927 files you need. In your board directory, you will need at least
3928 the "Makefile" and a "<board>.c".
3929 2. Create a new configuration file "include/configs/<board>.h" for
3931 3. If you're porting U-Boot to a new CPU, then also create a new
3932 directory to hold your CPU specific code. Add any files you need.
3933 4. Run "make <board>_defconfig" with your new name.
3934 5. Type "make", and you should get a working "u-boot.srec" file
3935 to be installed on your target system.
3936 6. Debug and solve any problems that might arise.
3937 [Of course, this last step is much harder than it sounds.]
3940 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3941 ==============================================================
3943 If you have modified U-Boot sources (for instance added a new board
3944 or support for new devices, a new CPU, etc.) you are expected to
3945 provide feedback to the other developers. The feedback normally takes
3946 the form of a "patch", i. e. a context diff against a certain (latest
3947 official or latest in the git repository) version of U-Boot sources.
3949 But before you submit such a patch, please verify that your modifi-
3950 cation did not break existing code. At least make sure that *ALL* of
3951 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3952 just run the buildman script (tools/buildman/buildman), which will
3953 configure and build U-Boot for ALL supported system. Be warned, this
3954 will take a while. Please see the buildman README, or run 'buildman -H'
3958 See also "U-Boot Porting Guide" below.
3961 Monitor Commands - Overview:
3962 ============================
3964 go - start application at address 'addr'
3965 run - run commands in an environment variable
3966 bootm - boot application image from memory
3967 bootp - boot image via network using BootP/TFTP protocol
3968 bootz - boot zImage from memory
3969 tftpboot- boot image via network using TFTP protocol
3970 and env variables "ipaddr" and "serverip"
3971 (and eventually "gatewayip")
3972 tftpput - upload a file via network using TFTP protocol
3973 rarpboot- boot image via network using RARP/TFTP protocol
3974 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3975 loads - load S-Record file over serial line
3976 loadb - load binary file over serial line (kermit mode)
3978 mm - memory modify (auto-incrementing)
3979 nm - memory modify (constant address)
3980 mw - memory write (fill)
3982 cmp - memory compare
3983 crc32 - checksum calculation
3984 i2c - I2C sub-system
3985 sspi - SPI utility commands
3986 base - print or set address offset
3987 printenv- print environment variables
3988 setenv - set environment variables
3989 saveenv - save environment variables to persistent storage
3990 protect - enable or disable FLASH write protection
3991 erase - erase FLASH memory
3992 flinfo - print FLASH memory information
3993 nand - NAND memory operations (see doc/README.nand)
3994 bdinfo - print Board Info structure
3995 iminfo - print header information for application image
3996 coninfo - print console devices and informations
3997 ide - IDE sub-system
3998 loop - infinite loop on address range
3999 loopw - infinite write loop on address range
4000 mtest - simple RAM test
4001 icache - enable or disable instruction cache
4002 dcache - enable or disable data cache
4003 reset - Perform RESET of the CPU
4004 echo - echo args to console
4005 version - print monitor version
4006 help - print online help
4007 ? - alias for 'help'
4010 Monitor Commands - Detailed Description:
4011 ========================================
4015 For now: just type "help <command>".
4018 Environment Variables:
4019 ======================
4021 U-Boot supports user configuration using Environment Variables which
4022 can be made persistent by saving to Flash memory.
4024 Environment Variables are set using "setenv", printed using
4025 "printenv", and saved to Flash using "saveenv". Using "setenv"
4026 without a value can be used to delete a variable from the
4027 environment. As long as you don't save the environment you are
4028 working with an in-memory copy. In case the Flash area containing the
4029 environment is erased by accident, a default environment is provided.
4031 Some configuration options can be set using Environment Variables.
4033 List of environment variables (most likely not complete):
4035 baudrate - see CONFIG_BAUDRATE
4037 bootdelay - see CONFIG_BOOTDELAY
4039 bootcmd - see CONFIG_BOOTCOMMAND
4041 bootargs - Boot arguments when booting an RTOS image
4043 bootfile - Name of the image to load with TFTP
4045 bootm_low - Memory range available for image processing in the bootm
4046 command can be restricted. This variable is given as
4047 a hexadecimal number and defines lowest address allowed
4048 for use by the bootm command. See also "bootm_size"
4049 environment variable. Address defined by "bootm_low" is
4050 also the base of the initial memory mapping for the Linux
4051 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4054 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4055 This variable is given as a hexadecimal number and it
4056 defines the size of the memory region starting at base
4057 address bootm_low that is accessible by the Linux kernel
4058 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4059 as the default value if it is defined, and bootm_size is
4062 bootm_size - Memory range available for image processing in the bootm
4063 command can be restricted. This variable is given as
4064 a hexadecimal number and defines the size of the region
4065 allowed for use by the bootm command. See also "bootm_low"
4066 environment variable.
4068 updatefile - Location of the software update file on a TFTP server, used
4069 by the automatic software update feature. Please refer to
4070 documentation in doc/README.update for more details.
4072 autoload - if set to "no" (any string beginning with 'n'),
4073 "bootp" will just load perform a lookup of the
4074 configuration from the BOOTP server, but not try to
4075 load any image using TFTP
4077 autostart - if set to "yes", an image loaded using the "bootp",
4078 "rarpboot", "tftpboot" or "diskboot" commands will
4079 be automatically started (by internally calling
4082 If set to "no", a standalone image passed to the
4083 "bootm" command will be copied to the load address
4084 (and eventually uncompressed), but NOT be started.
4085 This can be used to load and uncompress arbitrary
4088 fdt_high - if set this restricts the maximum address that the
4089 flattened device tree will be copied into upon boot.
4090 For example, if you have a system with 1 GB memory
4091 at physical address 0x10000000, while Linux kernel
4092 only recognizes the first 704 MB as low memory, you
4093 may need to set fdt_high as 0x3C000000 to have the
4094 device tree blob be copied to the maximum address
4095 of the 704 MB low memory, so that Linux kernel can
4096 access it during the boot procedure.
4098 If this is set to the special value 0xFFFFFFFF then
4099 the fdt will not be copied at all on boot. For this
4100 to work it must reside in writable memory, have
4101 sufficient padding on the end of it for u-boot to
4102 add the information it needs into it, and the memory
4103 must be accessible by the kernel.
4105 fdtcontroladdr- if set this is the address of the control flattened
4106 device tree used by U-Boot when CONFIG_OF_CONTROL is
4109 i2cfast - (PPC405GP|PPC405EP only)
4110 if set to 'y' configures Linux I2C driver for fast
4111 mode (400kHZ). This environment variable is used in
4112 initialization code. So, for changes to be effective
4113 it must be saved and board must be reset.
4115 initrd_high - restrict positioning of initrd images:
4116 If this variable is not set, initrd images will be
4117 copied to the highest possible address in RAM; this
4118 is usually what you want since it allows for
4119 maximum initrd size. If for some reason you want to
4120 make sure that the initrd image is loaded below the
4121 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4122 variable to a value of "no" or "off" or "0".
4123 Alternatively, you can set it to a maximum upper
4124 address to use (U-Boot will still check that it
4125 does not overwrite the U-Boot stack and data).
4127 For instance, when you have a system with 16 MB
4128 RAM, and want to reserve 4 MB from use by Linux,
4129 you can do this by adding "mem=12M" to the value of
4130 the "bootargs" variable. However, now you must make
4131 sure that the initrd image is placed in the first
4132 12 MB as well - this can be done with
4134 setenv initrd_high 00c00000
4136 If you set initrd_high to 0xFFFFFFFF, this is an
4137 indication to U-Boot that all addresses are legal
4138 for the Linux kernel, including addresses in flash
4139 memory. In this case U-Boot will NOT COPY the
4140 ramdisk at all. This may be useful to reduce the
4141 boot time on your system, but requires that this
4142 feature is supported by your Linux kernel.
4144 ipaddr - IP address; needed for tftpboot command
4146 loadaddr - Default load address for commands like "bootp",
4147 "rarpboot", "tftpboot", "loadb" or "diskboot"
4149 loads_echo - see CONFIG_LOADS_ECHO
4151 serverip - TFTP server IP address; needed for tftpboot command
4153 bootretry - see CONFIG_BOOT_RETRY_TIME
4155 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4157 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4159 ethprime - controls which interface is used first.
4161 ethact - controls which interface is currently active.
4162 For example you can do the following
4164 => setenv ethact FEC
4165 => ping 192.168.0.1 # traffic sent on FEC
4166 => setenv ethact SCC
4167 => ping 10.0.0.1 # traffic sent on SCC
4169 ethrotate - When set to "no" U-Boot does not go through all
4170 available network interfaces.
4171 It just stays at the currently selected interface.
4173 netretry - When set to "no" each network operation will
4174 either succeed or fail without retrying.
4175 When set to "once" the network operation will
4176 fail when all the available network interfaces
4177 are tried once without success.
4178 Useful on scripts which control the retry operation
4181 npe_ucode - set load address for the NPE microcode
4183 silent_linux - If set then Linux will be told to boot silently, by
4184 changing the console to be empty. If "yes" it will be
4185 made silent. If "no" it will not be made silent. If
4186 unset, then it will be made silent if the U-Boot console
4189 tftpsrcp - If this is set, the value is used for TFTP's
4192 tftpdstp - If this is set, the value is used for TFTP's UDP
4193 destination port instead of the Well Know Port 69.
4195 tftpblocksize - Block size to use for TFTP transfers; if not set,
4196 we use the TFTP server's default block size
4198 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4199 seconds, minimum value is 1000 = 1 second). Defines
4200 when a packet is considered to be lost so it has to
4201 be retransmitted. The default is 5000 = 5 seconds.
4202 Lowering this value may make downloads succeed
4203 faster in networks with high packet loss rates or
4204 with unreliable TFTP servers.
4206 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4207 unit, minimum value = 0). Defines how many timeouts
4208 can happen during a single file transfer before that
4209 transfer is aborted. The default is 10, and 0 means
4210 'no timeouts allowed'. Increasing this value may help
4211 downloads succeed with high packet loss rates, or with
4212 unreliable TFTP servers or client hardware.
4214 vlan - When set to a value < 4095 the traffic over
4215 Ethernet is encapsulated/received over 802.1q
4218 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4219 Unsigned value, in milliseconds. If not set, the period will
4220 be either the default (28000), or a value based on
4221 CONFIG_NET_RETRY_COUNT, if defined. This value has
4222 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4224 The following image location variables contain the location of images
4225 used in booting. The "Image" column gives the role of the image and is
4226 not an environment variable name. The other columns are environment
4227 variable names. "File Name" gives the name of the file on a TFTP
4228 server, "RAM Address" gives the location in RAM the image will be
4229 loaded to, and "Flash Location" gives the image's address in NOR
4230 flash or offset in NAND flash.
4232 *Note* - these variables don't have to be defined for all boards, some
4233 boards currently use other variables for these purposes, and some
4234 boards use these variables for other purposes.
4236 Image File Name RAM Address Flash Location
4237 ----- --------- ----------- --------------
4238 u-boot u-boot u-boot_addr_r u-boot_addr
4239 Linux kernel bootfile kernel_addr_r kernel_addr
4240 device tree blob fdtfile fdt_addr_r fdt_addr
4241 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4243 The following environment variables may be used and automatically
4244 updated by the network boot commands ("bootp" and "rarpboot"),
4245 depending the information provided by your boot server:
4247 bootfile - see above
4248 dnsip - IP address of your Domain Name Server
4249 dnsip2 - IP address of your secondary Domain Name Server
4250 gatewayip - IP address of the Gateway (Router) to use
4251 hostname - Target hostname
4253 netmask - Subnet Mask
4254 rootpath - Pathname of the root filesystem on the NFS server
4255 serverip - see above
4258 There are two special Environment Variables:
4260 serial# - contains hardware identification information such
4261 as type string and/or serial number
4262 ethaddr - Ethernet address
4264 These variables can be set only once (usually during manufacturing of
4265 the board). U-Boot refuses to delete or overwrite these variables
4266 once they have been set once.
4269 Further special Environment Variables:
4271 ver - Contains the U-Boot version string as printed
4272 with the "version" command. This variable is
4273 readonly (see CONFIG_VERSION_VARIABLE).
4276 Please note that changes to some configuration parameters may take
4277 only effect after the next boot (yes, that's just like Windoze :-).
4280 Callback functions for environment variables:
4281 ---------------------------------------------
4283 For some environment variables, the behavior of u-boot needs to change
4284 when their values are changed. This functionality allows functions to
4285 be associated with arbitrary variables. On creation, overwrite, or
4286 deletion, the callback will provide the opportunity for some side
4287 effect to happen or for the change to be rejected.
4289 The callbacks are named and associated with a function using the
4290 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4292 These callbacks are associated with variables in one of two ways. The
4293 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4294 in the board configuration to a string that defines a list of
4295 associations. The list must be in the following format:
4297 entry = variable_name[:callback_name]
4300 If the callback name is not specified, then the callback is deleted.
4301 Spaces are also allowed anywhere in the list.
4303 Callbacks can also be associated by defining the ".callbacks" variable
4304 with the same list format above. Any association in ".callbacks" will
4305 override any association in the static list. You can define
4306 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4307 ".callbacks" environment variable in the default or embedded environment.
4309 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4310 regular expression. This allows multiple variables to be connected to
4311 the same callback without explicitly listing them all out.
4314 Command Line Parsing:
4315 =====================
4317 There are two different command line parsers available with U-Boot:
4318 the old "simple" one, and the much more powerful "hush" shell:
4320 Old, simple command line parser:
4321 --------------------------------
4323 - supports environment variables (through setenv / saveenv commands)
4324 - several commands on one line, separated by ';'
4325 - variable substitution using "... ${name} ..." syntax
4326 - special characters ('$', ';') can be escaped by prefixing with '\',
4328 setenv bootcmd bootm \${address}
4329 - You can also escape text by enclosing in single apostrophes, for example:
4330 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4335 - similar to Bourne shell, with control structures like
4336 if...then...else...fi, for...do...done; while...do...done,
4337 until...do...done, ...
4338 - supports environment ("global") variables (through setenv / saveenv
4339 commands) and local shell variables (through standard shell syntax
4340 "name=value"); only environment variables can be used with "run"
4346 (1) If a command line (or an environment variable executed by a "run"
4347 command) contains several commands separated by semicolon, and
4348 one of these commands fails, then the remaining commands will be
4351 (2) If you execute several variables with one call to run (i. e.
4352 calling run with a list of variables as arguments), any failing
4353 command will cause "run" to terminate, i. e. the remaining
4354 variables are not executed.
4356 Note for Redundant Ethernet Interfaces:
4357 =======================================
4359 Some boards come with redundant Ethernet interfaces; U-Boot supports
4360 such configurations and is capable of automatic selection of a
4361 "working" interface when needed. MAC assignment works as follows:
4363 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4364 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4365 "eth1addr" (=>eth1), "eth2addr", ...
4367 If the network interface stores some valid MAC address (for instance
4368 in SROM), this is used as default address if there is NO correspon-
4369 ding setting in the environment; if the corresponding environment
4370 variable is set, this overrides the settings in the card; that means:
4372 o If the SROM has a valid MAC address, and there is no address in the
4373 environment, the SROM's address is used.
4375 o If there is no valid address in the SROM, and a definition in the
4376 environment exists, then the value from the environment variable is
4379 o If both the SROM and the environment contain a MAC address, and
4380 both addresses are the same, this MAC address is used.
4382 o If both the SROM and the environment contain a MAC address, and the
4383 addresses differ, the value from the environment is used and a
4386 o If neither SROM nor the environment contain a MAC address, an error
4387 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4388 a random, locally-assigned MAC is used.
4390 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4391 will be programmed into hardware as part of the initialization process. This
4392 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4393 The naming convention is as follows:
4394 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4399 U-Boot is capable of booting (and performing other auxiliary operations on)
4400 images in two formats:
4402 New uImage format (FIT)
4403 -----------------------
4405 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4406 to Flattened Device Tree). It allows the use of images with multiple
4407 components (several kernels, ramdisks, etc.), with contents protected by
4408 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4414 Old image format is based on binary files which can be basically anything,
4415 preceded by a special header; see the definitions in include/image.h for
4416 details; basically, the header defines the following image properties:
4418 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4419 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4420 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4421 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4423 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4424 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4425 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4426 * Compression Type (uncompressed, gzip, bzip2)
4432 The header is marked by a special Magic Number, and both the header
4433 and the data portions of the image are secured against corruption by
4440 Although U-Boot should support any OS or standalone application
4441 easily, the main focus has always been on Linux during the design of
4444 U-Boot includes many features that so far have been part of some
4445 special "boot loader" code within the Linux kernel. Also, any
4446 "initrd" images to be used are no longer part of one big Linux image;
4447 instead, kernel and "initrd" are separate images. This implementation
4448 serves several purposes:
4450 - the same features can be used for other OS or standalone
4451 applications (for instance: using compressed images to reduce the
4452 Flash memory footprint)
4454 - it becomes much easier to port new Linux kernel versions because
4455 lots of low-level, hardware dependent stuff are done by U-Boot
4457 - the same Linux kernel image can now be used with different "initrd"
4458 images; of course this also means that different kernel images can
4459 be run with the same "initrd". This makes testing easier (you don't
4460 have to build a new "zImage.initrd" Linux image when you just
4461 change a file in your "initrd"). Also, a field-upgrade of the
4462 software is easier now.
4468 Porting Linux to U-Boot based systems:
4469 ---------------------------------------
4471 U-Boot cannot save you from doing all the necessary modifications to
4472 configure the Linux device drivers for use with your target hardware
4473 (no, we don't intend to provide a full virtual machine interface to
4476 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4478 Just make sure your machine specific header file (for instance
4479 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4480 Information structure as we define in include/asm-<arch>/u-boot.h,
4481 and make sure that your definition of IMAP_ADDR uses the same value
4482 as your U-Boot configuration in CONFIG_SYS_IMMR.
4484 Note that U-Boot now has a driver model, a unified model for drivers.
4485 If you are adding a new driver, plumb it into driver model. If there
4486 is no uclass available, you are encouraged to create one. See
4490 Configuring the Linux kernel:
4491 -----------------------------
4493 No specific requirements for U-Boot. Make sure you have some root
4494 device (initial ramdisk, NFS) for your target system.
4497 Building a Linux Image:
4498 -----------------------
4500 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4501 not used. If you use recent kernel source, a new build target
4502 "uImage" will exist which automatically builds an image usable by
4503 U-Boot. Most older kernels also have support for a "pImage" target,
4504 which was introduced for our predecessor project PPCBoot and uses a
4505 100% compatible format.
4509 make TQM850L_defconfig
4514 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4515 encapsulate a compressed Linux kernel image with header information,
4516 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4518 * build a standard "vmlinux" kernel image (in ELF binary format):
4520 * convert the kernel into a raw binary image:
4522 ${CROSS_COMPILE}-objcopy -O binary \
4523 -R .note -R .comment \
4524 -S vmlinux linux.bin
4526 * compress the binary image:
4530 * package compressed binary image for U-Boot:
4532 mkimage -A ppc -O linux -T kernel -C gzip \
4533 -a 0 -e 0 -n "Linux Kernel Image" \
4534 -d linux.bin.gz uImage
4537 The "mkimage" tool can also be used to create ramdisk images for use
4538 with U-Boot, either separated from the Linux kernel image, or
4539 combined into one file. "mkimage" encapsulates the images with a 64
4540 byte header containing information about target architecture,
4541 operating system, image type, compression method, entry points, time
4542 stamp, CRC32 checksums, etc.
4544 "mkimage" can be called in two ways: to verify existing images and
4545 print the header information, or to build new images.
4547 In the first form (with "-l" option) mkimage lists the information
4548 contained in the header of an existing U-Boot image; this includes
4549 checksum verification:
4551 tools/mkimage -l image
4552 -l ==> list image header information
4554 The second form (with "-d" option) is used to build a U-Boot image
4555 from a "data file" which is used as image payload:
4557 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4558 -n name -d data_file image
4559 -A ==> set architecture to 'arch'
4560 -O ==> set operating system to 'os'
4561 -T ==> set image type to 'type'
4562 -C ==> set compression type 'comp'
4563 -a ==> set load address to 'addr' (hex)
4564 -e ==> set entry point to 'ep' (hex)
4565 -n ==> set image name to 'name'
4566 -d ==> use image data from 'datafile'
4568 Right now, all Linux kernels for PowerPC systems use the same load
4569 address (0x00000000), but the entry point address depends on the
4572 - 2.2.x kernels have the entry point at 0x0000000C,
4573 - 2.3.x and later kernels have the entry point at 0x00000000.
4575 So a typical call to build a U-Boot image would read:
4577 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4578 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4579 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4580 > examples/uImage.TQM850L
4581 Image Name: 2.4.4 kernel for TQM850L
4582 Created: Wed Jul 19 02:34:59 2000
4583 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4584 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4585 Load Address: 0x00000000
4586 Entry Point: 0x00000000
4588 To verify the contents of the image (or check for corruption):
4590 -> tools/mkimage -l examples/uImage.TQM850L
4591 Image Name: 2.4.4 kernel for TQM850L
4592 Created: Wed Jul 19 02:34:59 2000
4593 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4594 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4595 Load Address: 0x00000000
4596 Entry Point: 0x00000000
4598 NOTE: for embedded systems where boot time is critical you can trade
4599 speed for memory and install an UNCOMPRESSED image instead: this
4600 needs more space in Flash, but boots much faster since it does not
4601 need to be uncompressed:
4603 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4604 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4605 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4606 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4607 > examples/uImage.TQM850L-uncompressed
4608 Image Name: 2.4.4 kernel for TQM850L
4609 Created: Wed Jul 19 02:34:59 2000
4610 Image Type: PowerPC Linux Kernel Image (uncompressed)
4611 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4612 Load Address: 0x00000000
4613 Entry Point: 0x00000000
4616 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4617 when your kernel is intended to use an initial ramdisk:
4619 -> tools/mkimage -n 'Simple Ramdisk Image' \
4620 > -A ppc -O linux -T ramdisk -C gzip \
4621 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4622 Image Name: Simple Ramdisk Image
4623 Created: Wed Jan 12 14:01:50 2000
4624 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4625 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4626 Load Address: 0x00000000
4627 Entry Point: 0x00000000
4629 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4630 option performs the converse operation of the mkimage's second form (the "-d"
4631 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4634 tools/dumpimage -i image -T type -p position data_file
4635 -i ==> extract from the 'image' a specific 'data_file'
4636 -T ==> set image type to 'type'
4637 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4640 Installing a Linux Image:
4641 -------------------------
4643 To downloading a U-Boot image over the serial (console) interface,
4644 you must convert the image to S-Record format:
4646 objcopy -I binary -O srec examples/image examples/image.srec
4648 The 'objcopy' does not understand the information in the U-Boot
4649 image header, so the resulting S-Record file will be relative to
4650 address 0x00000000. To load it to a given address, you need to
4651 specify the target address as 'offset' parameter with the 'loads'
4654 Example: install the image to address 0x40100000 (which on the
4655 TQM8xxL is in the first Flash bank):
4657 => erase 40100000 401FFFFF
4663 ## Ready for S-Record download ...
4664 ~>examples/image.srec
4665 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4667 15989 15990 15991 15992
4668 [file transfer complete]
4670 ## Start Addr = 0x00000000
4673 You can check the success of the download using the 'iminfo' command;
4674 this includes a checksum verification so you can be sure no data
4675 corruption happened:
4679 ## Checking Image at 40100000 ...
4680 Image Name: 2.2.13 for initrd on TQM850L
4681 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4682 Data Size: 335725 Bytes = 327 kB = 0 MB
4683 Load Address: 00000000
4684 Entry Point: 0000000c
4685 Verifying Checksum ... OK
4691 The "bootm" command is used to boot an application that is stored in
4692 memory (RAM or Flash). In case of a Linux kernel image, the contents
4693 of the "bootargs" environment variable is passed to the kernel as
4694 parameters. You can check and modify this variable using the
4695 "printenv" and "setenv" commands:
4698 => printenv bootargs
4699 bootargs=root=/dev/ram
4701 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4703 => printenv bootargs
4704 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4707 ## Booting Linux kernel at 40020000 ...
4708 Image Name: 2.2.13 for NFS on TQM850L
4709 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4710 Data Size: 381681 Bytes = 372 kB = 0 MB
4711 Load Address: 00000000
4712 Entry Point: 0000000c
4713 Verifying Checksum ... OK
4714 Uncompressing Kernel Image ... OK
4715 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
4716 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4717 time_init: decrementer frequency = 187500000/60
4718 Calibrating delay loop... 49.77 BogoMIPS
4719 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4722 If you want to boot a Linux kernel with initial RAM disk, you pass
4723 the memory addresses of both the kernel and the initrd image (PPBCOOT
4724 format!) to the "bootm" command:
4726 => imi 40100000 40200000
4728 ## Checking Image at 40100000 ...
4729 Image Name: 2.2.13 for initrd on TQM850L
4730 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4731 Data Size: 335725 Bytes = 327 kB = 0 MB
4732 Load Address: 00000000
4733 Entry Point: 0000000c
4734 Verifying Checksum ... OK
4736 ## Checking Image at 40200000 ...
4737 Image Name: Simple Ramdisk Image
4738 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4739 Data Size: 566530 Bytes = 553 kB = 0 MB
4740 Load Address: 00000000
4741 Entry Point: 00000000
4742 Verifying Checksum ... OK
4744 => bootm 40100000 40200000
4745 ## Booting Linux kernel at 40100000 ...
4746 Image Name: 2.2.13 for initrd on TQM850L
4747 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4748 Data Size: 335725 Bytes = 327 kB = 0 MB
4749 Load Address: 00000000
4750 Entry Point: 0000000c
4751 Verifying Checksum ... OK
4752 Uncompressing Kernel Image ... OK
4753 ## Loading RAMDisk Image at 40200000 ...
4754 Image Name: Simple Ramdisk Image
4755 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4756 Data Size: 566530 Bytes = 553 kB = 0 MB
4757 Load Address: 00000000
4758 Entry Point: 00000000
4759 Verifying Checksum ... OK
4760 Loading Ramdisk ... OK
4761 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
4762 Boot arguments: root=/dev/ram
4763 time_init: decrementer frequency = 187500000/60
4764 Calibrating delay loop... 49.77 BogoMIPS
4766 RAMDISK: Compressed image found at block 0
4767 VFS: Mounted root (ext2 filesystem).
4771 Boot Linux and pass a flat device tree:
4774 First, U-Boot must be compiled with the appropriate defines. See the section
4775 titled "Linux Kernel Interface" above for a more in depth explanation. The
4776 following is an example of how to start a kernel and pass an updated
4782 oft=oftrees/mpc8540ads.dtb
4783 => tftp $oftaddr $oft
4784 Speed: 1000, full duplex
4786 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4787 Filename 'oftrees/mpc8540ads.dtb'.
4788 Load address: 0x300000
4791 Bytes transferred = 4106 (100a hex)
4792 => tftp $loadaddr $bootfile
4793 Speed: 1000, full duplex
4795 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4797 Load address: 0x200000
4798 Loading:############
4800 Bytes transferred = 1029407 (fb51f hex)
4805 => bootm $loadaddr - $oftaddr
4806 ## Booting image at 00200000 ...
4807 Image Name: Linux-2.6.17-dirty
4808 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4809 Data Size: 1029343 Bytes = 1005.2 kB
4810 Load Address: 00000000
4811 Entry Point: 00000000
4812 Verifying Checksum ... OK
4813 Uncompressing Kernel Image ... OK
4814 Booting using flat device tree at 0x300000
4815 Using MPC85xx ADS machine description
4816 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4820 More About U-Boot Image Types:
4821 ------------------------------
4823 U-Boot supports the following image types:
4825 "Standalone Programs" are directly runnable in the environment
4826 provided by U-Boot; it is expected that (if they behave
4827 well) you can continue to work in U-Boot after return from
4828 the Standalone Program.
4829 "OS Kernel Images" are usually images of some Embedded OS which
4830 will take over control completely. Usually these programs
4831 will install their own set of exception handlers, device
4832 drivers, set up the MMU, etc. - this means, that you cannot
4833 expect to re-enter U-Boot except by resetting the CPU.
4834 "RAMDisk Images" are more or less just data blocks, and their
4835 parameters (address, size) are passed to an OS kernel that is
4837 "Multi-File Images" contain several images, typically an OS
4838 (Linux) kernel image and one or more data images like
4839 RAMDisks. This construct is useful for instance when you want
4840 to boot over the network using BOOTP etc., where the boot
4841 server provides just a single image file, but you want to get
4842 for instance an OS kernel and a RAMDisk image.
4844 "Multi-File Images" start with a list of image sizes, each
4845 image size (in bytes) specified by an "uint32_t" in network
4846 byte order. This list is terminated by an "(uint32_t)0".
4847 Immediately after the terminating 0 follow the images, one by
4848 one, all aligned on "uint32_t" boundaries (size rounded up to
4849 a multiple of 4 bytes).
4851 "Firmware Images" are binary images containing firmware (like
4852 U-Boot or FPGA images) which usually will be programmed to
4855 "Script files" are command sequences that will be executed by
4856 U-Boot's command interpreter; this feature is especially
4857 useful when you configure U-Boot to use a real shell (hush)
4858 as command interpreter.
4860 Booting the Linux zImage:
4861 -------------------------
4863 On some platforms, it's possible to boot Linux zImage. This is done
4864 using the "bootz" command. The syntax of "bootz" command is the same
4865 as the syntax of "bootm" command.
4867 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4868 kernel with raw initrd images. The syntax is slightly different, the
4869 address of the initrd must be augmented by it's size, in the following
4870 format: "<initrd addres>:<initrd size>".
4876 One of the features of U-Boot is that you can dynamically load and
4877 run "standalone" applications, which can use some resources of
4878 U-Boot like console I/O functions or interrupt services.
4880 Two simple examples are included with the sources:
4885 'examples/hello_world.c' contains a small "Hello World" Demo
4886 application; it is automatically compiled when you build U-Boot.
4887 It's configured to run at address 0x00040004, so you can play with it
4891 ## Ready for S-Record download ...
4892 ~>examples/hello_world.srec
4893 1 2 3 4 5 6 7 8 9 10 11 ...
4894 [file transfer complete]
4896 ## Start Addr = 0x00040004
4898 => go 40004 Hello World! This is a test.
4899 ## Starting application at 0x00040004 ...
4910 Hit any key to exit ...
4912 ## Application terminated, rc = 0x0
4914 Another example, which demonstrates how to register a CPM interrupt
4915 handler with the U-Boot code, can be found in 'examples/timer.c'.
4916 Here, a CPM timer is set up to generate an interrupt every second.
4917 The interrupt service routine is trivial, just printing a '.'
4918 character, but this is just a demo program. The application can be
4919 controlled by the following keys:
4921 ? - print current values og the CPM Timer registers
4922 b - enable interrupts and start timer
4923 e - stop timer and disable interrupts
4924 q - quit application
4927 ## Ready for S-Record download ...
4928 ~>examples/timer.srec
4929 1 2 3 4 5 6 7 8 9 10 11 ...
4930 [file transfer complete]
4932 ## Start Addr = 0x00040004
4935 ## Starting application at 0x00040004 ...
4938 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4941 [q, b, e, ?] Set interval 1000000 us
4944 [q, b, e, ?] ........
4945 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4948 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4951 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4954 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4956 [q, b, e, ?] ...Stopping timer
4958 [q, b, e, ?] ## Application terminated, rc = 0x0
4964 Over time, many people have reported problems when trying to use the
4965 "minicom" terminal emulation program for serial download. I (wd)
4966 consider minicom to be broken, and recommend not to use it. Under
4967 Unix, I recommend to use C-Kermit for general purpose use (and
4968 especially for kermit binary protocol download ("loadb" command), and
4969 use "cu" for S-Record download ("loads" command). See
4970 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4971 for help with kermit.
4974 Nevertheless, if you absolutely want to use it try adding this
4975 configuration to your "File transfer protocols" section:
4977 Name Program Name U/D FullScr IO-Red. Multi
4978 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4979 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4985 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4986 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4988 Building requires a cross environment; it is known to work on
4989 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4990 need gmake since the Makefiles are not compatible with BSD make).
4991 Note that the cross-powerpc package does not install include files;
4992 attempting to build U-Boot will fail because <machine/ansi.h> is
4993 missing. This file has to be installed and patched manually:
4995 # cd /usr/pkg/cross/powerpc-netbsd/include
4997 # ln -s powerpc machine
4998 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4999 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5001 Native builds *don't* work due to incompatibilities between native
5002 and U-Boot include files.
5004 Booting assumes that (the first part of) the image booted is a
5005 stage-2 loader which in turn loads and then invokes the kernel
5006 proper. Loader sources will eventually appear in the NetBSD source
5007 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5008 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5011 Implementation Internals:
5012 =========================
5014 The following is not intended to be a complete description of every
5015 implementation detail. However, it should help to understand the
5016 inner workings of U-Boot and make it easier to port it to custom
5020 Initial Stack, Global Data:
5021 ---------------------------
5023 The implementation of U-Boot is complicated by the fact that U-Boot
5024 starts running out of ROM (flash memory), usually without access to
5025 system RAM (because the memory controller is not initialized yet).
5026 This means that we don't have writable Data or BSS segments, and BSS
5027 is not initialized as zero. To be able to get a C environment working
5028 at all, we have to allocate at least a minimal stack. Implementation
5029 options for this are defined and restricted by the CPU used: Some CPU
5030 models provide on-chip memory (like the IMMR area on MPC8xx and
5031 MPC826x processors), on others (parts of) the data cache can be
5032 locked as (mis-) used as memory, etc.
5034 Chris Hallinan posted a good summary of these issues to the
5035 U-Boot mailing list:
5037 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5038 From: "Chris Hallinan" <clh@net1plus.com>
5039 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5042 Correct me if I'm wrong, folks, but the way I understand it
5043 is this: Using DCACHE as initial RAM for Stack, etc, does not
5044 require any physical RAM backing up the cache. The cleverness
5045 is that the cache is being used as a temporary supply of
5046 necessary storage before the SDRAM controller is setup. It's
5047 beyond the scope of this list to explain the details, but you
5048 can see how this works by studying the cache architecture and
5049 operation in the architecture and processor-specific manuals.
5051 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5052 is another option for the system designer to use as an
5053 initial stack/RAM area prior to SDRAM being available. Either
5054 option should work for you. Using CS 4 should be fine if your
5055 board designers haven't used it for something that would
5056 cause you grief during the initial boot! It is frequently not
5059 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5060 with your processor/board/system design. The default value
5061 you will find in any recent u-boot distribution in
5062 walnut.h should work for you. I'd set it to a value larger
5063 than your SDRAM module. If you have a 64MB SDRAM module, set
5064 it above 400_0000. Just make sure your board has no resources
5065 that are supposed to respond to that address! That code in
5066 start.S has been around a while and should work as is when
5067 you get the config right.
5072 It is essential to remember this, since it has some impact on the C
5073 code for the initialization procedures:
5075 * Initialized global data (data segment) is read-only. Do not attempt
5078 * Do not use any uninitialized global data (or implicitly initialized
5079 as zero data - BSS segment) at all - this is undefined, initiali-
5080 zation is performed later (when relocating to RAM).
5082 * Stack space is very limited. Avoid big data buffers or things like
5085 Having only the stack as writable memory limits means we cannot use
5086 normal global data to share information between the code. But it
5087 turned out that the implementation of U-Boot can be greatly
5088 simplified by making a global data structure (gd_t) available to all
5089 functions. We could pass a pointer to this data as argument to _all_
5090 functions, but this would bloat the code. Instead we use a feature of
5091 the GCC compiler (Global Register Variables) to share the data: we
5092 place a pointer (gd) to the global data into a register which we
5093 reserve for this purpose.
5095 When choosing a register for such a purpose we are restricted by the
5096 relevant (E)ABI specifications for the current architecture, and by
5097 GCC's implementation.
5099 For PowerPC, the following registers have specific use:
5101 R2: reserved for system use
5102 R3-R4: parameter passing and return values
5103 R5-R10: parameter passing
5104 R13: small data area pointer
5108 (U-Boot also uses R12 as internal GOT pointer. r12
5109 is a volatile register so r12 needs to be reset when
5110 going back and forth between asm and C)
5112 ==> U-Boot will use R2 to hold a pointer to the global data
5114 Note: on PPC, we could use a static initializer (since the
5115 address of the global data structure is known at compile time),
5116 but it turned out that reserving a register results in somewhat
5117 smaller code - although the code savings are not that big (on
5118 average for all boards 752 bytes for the whole U-Boot image,
5119 624 text + 127 data).
5121 On ARM, the following registers are used:
5123 R0: function argument word/integer result
5124 R1-R3: function argument word
5125 R9: platform specific
5126 R10: stack limit (used only if stack checking is enabled)
5127 R11: argument (frame) pointer
5128 R12: temporary workspace
5131 R15: program counter
5133 ==> U-Boot will use R9 to hold a pointer to the global data
5135 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5137 On Nios II, the ABI is documented here:
5138 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5140 ==> U-Boot will use gp to hold a pointer to the global data
5142 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5143 to access small data sections, so gp is free.
5145 On NDS32, the following registers are used:
5147 R0-R1: argument/return
5149 R15: temporary register for assembler
5150 R16: trampoline register
5151 R28: frame pointer (FP)
5152 R29: global pointer (GP)
5153 R30: link register (LP)
5154 R31: stack pointer (SP)
5155 PC: program counter (PC)
5157 ==> U-Boot will use R10 to hold a pointer to the global data
5159 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5160 or current versions of GCC may "optimize" the code too much.
5165 U-Boot runs in system state and uses physical addresses, i.e. the
5166 MMU is not used either for address mapping nor for memory protection.
5168 The available memory is mapped to fixed addresses using the memory
5169 controller. In this process, a contiguous block is formed for each
5170 memory type (Flash, SDRAM, SRAM), even when it consists of several
5171 physical memory banks.
5173 U-Boot is installed in the first 128 kB of the first Flash bank (on
5174 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5175 booting and sizing and initializing DRAM, the code relocates itself
5176 to the upper end of DRAM. Immediately below the U-Boot code some
5177 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5178 configuration setting]. Below that, a structure with global Board
5179 Info data is placed, followed by the stack (growing downward).
5181 Additionally, some exception handler code is copied to the low 8 kB
5182 of DRAM (0x00000000 ... 0x00001FFF).
5184 So a typical memory configuration with 16 MB of DRAM could look like
5187 0x0000 0000 Exception Vector code
5190 0x0000 2000 Free for Application Use
5196 0x00FB FF20 Monitor Stack (Growing downward)
5197 0x00FB FFAC Board Info Data and permanent copy of global data
5198 0x00FC 0000 Malloc Arena
5201 0x00FE 0000 RAM Copy of Monitor Code
5202 ... eventually: LCD or video framebuffer
5203 ... eventually: pRAM (Protected RAM - unchanged by reset)
5204 0x00FF FFFF [End of RAM]
5207 System Initialization:
5208 ----------------------
5210 In the reset configuration, U-Boot starts at the reset entry point
5211 (on most PowerPC systems at address 0x00000100). Because of the reset
5212 configuration for CS0# this is a mirror of the on board Flash memory.
5213 To be able to re-map memory U-Boot then jumps to its link address.
5214 To be able to implement the initialization code in C, a (small!)
5215 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5216 which provide such a feature like), or in a locked part of the data
5217 cache. After that, U-Boot initializes the CPU core, the caches and
5220 Next, all (potentially) available memory banks are mapped using a
5221 preliminary mapping. For example, we put them on 512 MB boundaries
5222 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5223 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5224 programmed for SDRAM access. Using the temporary configuration, a
5225 simple memory test is run that determines the size of the SDRAM
5228 When there is more than one SDRAM bank, and the banks are of
5229 different size, the largest is mapped first. For equal size, the first
5230 bank (CS2#) is mapped first. The first mapping is always for address
5231 0x00000000, with any additional banks following immediately to create
5232 contiguous memory starting from 0.
5234 Then, the monitor installs itself at the upper end of the SDRAM area
5235 and allocates memory for use by malloc() and for the global Board
5236 Info data; also, the exception vector code is copied to the low RAM
5237 pages, and the final stack is set up.
5239 Only after this relocation will you have a "normal" C environment;
5240 until that you are restricted in several ways, mostly because you are
5241 running from ROM, and because the code will have to be relocated to a
5245 U-Boot Porting Guide:
5246 ----------------------
5248 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5252 int main(int argc, char *argv[])
5254 sighandler_t no_more_time;
5256 signal(SIGALRM, no_more_time);
5257 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5259 if (available_money > available_manpower) {
5260 Pay consultant to port U-Boot;
5264 Download latest U-Boot source;
5266 Subscribe to u-boot mailing list;
5269 email("Hi, I am new to U-Boot, how do I get started?");
5272 Read the README file in the top level directory;
5273 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5274 Read applicable doc/*.README;
5275 Read the source, Luke;
5276 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5279 if (available_money > toLocalCurrency ($2500))
5282 Add a lot of aggravation and time;
5284 if (a similar board exists) { /* hopefully... */
5285 cp -a board/<similar> board/<myboard>
5286 cp include/configs/<similar>.h include/configs/<myboard>.h
5288 Create your own board support subdirectory;
5289 Create your own board include/configs/<myboard>.h file;
5291 Edit new board/<myboard> files
5292 Edit new include/configs/<myboard>.h
5297 Add / modify source code;
5301 email("Hi, I am having problems...");
5303 Send patch file to the U-Boot email list;
5304 if (reasonable critiques)
5305 Incorporate improvements from email list code review;
5307 Defend code as written;
5313 void no_more_time (int sig)
5322 All contributions to U-Boot should conform to the Linux kernel
5323 coding style; see the file "Documentation/CodingStyle" and the script
5324 "scripts/Lindent" in your Linux kernel source directory.
5326 Source files originating from a different project (for example the
5327 MTD subsystem) are generally exempt from these guidelines and are not
5328 reformatted to ease subsequent migration to newer versions of those
5331 Please note that U-Boot is implemented in C (and to some small parts in
5332 Assembler); no C++ is used, so please do not use C++ style comments (//)
5335 Please also stick to the following formatting rules:
5336 - remove any trailing white space
5337 - use TAB characters for indentation and vertical alignment, not spaces
5338 - make sure NOT to use DOS '\r\n' line feeds
5339 - do not add more than 2 consecutive empty lines to source files
5340 - do not add trailing empty lines to source files
5342 Submissions which do not conform to the standards may be returned
5343 with a request to reformat the changes.
5349 Since the number of patches for U-Boot is growing, we need to
5350 establish some rules. Submissions which do not conform to these rules
5351 may be rejected, even when they contain important and valuable stuff.
5353 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5355 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5356 see http://lists.denx.de/mailman/listinfo/u-boot
5358 When you send a patch, please include the following information with
5361 * For bug fixes: a description of the bug and how your patch fixes
5362 this bug. Please try to include a way of demonstrating that the
5363 patch actually fixes something.
5365 * For new features: a description of the feature and your
5368 * A CHANGELOG entry as plaintext (separate from the patch)
5370 * For major contributions, add a MAINTAINERS file with your
5371 information and associated file and directory references.
5373 * When you add support for a new board, don't forget to add a
5374 maintainer e-mail address to the boards.cfg file, too.
5376 * If your patch adds new configuration options, don't forget to
5377 document these in the README file.
5379 * The patch itself. If you are using git (which is *strongly*
5380 recommended) you can easily generate the patch using the
5381 "git format-patch". If you then use "git send-email" to send it to
5382 the U-Boot mailing list, you will avoid most of the common problems
5383 with some other mail clients.
5385 If you cannot use git, use "diff -purN OLD NEW". If your version of
5386 diff does not support these options, then get the latest version of
5389 The current directory when running this command shall be the parent
5390 directory of the U-Boot source tree (i. e. please make sure that
5391 your patch includes sufficient directory information for the
5394 We prefer patches as plain text. MIME attachments are discouraged,
5395 and compressed attachments must not be used.
5397 * If one logical set of modifications affects or creates several
5398 files, all these changes shall be submitted in a SINGLE patch file.
5400 * Changesets that contain different, unrelated modifications shall be
5401 submitted as SEPARATE patches, one patch per changeset.
5406 * Before sending the patch, run the buildman script on your patched
5407 source tree and make sure that no errors or warnings are reported
5408 for any of the boards.
5410 * Keep your modifications to the necessary minimum: A patch
5411 containing several unrelated changes or arbitrary reformats will be
5412 returned with a request to re-formatting / split it.
5414 * If you modify existing code, make sure that your new code does not
5415 add to the memory footprint of the code ;-) Small is beautiful!
5416 When adding new features, these should compile conditionally only
5417 (using #ifdef), and the resulting code with the new feature
5418 disabled must not need more memory than the old code without your
5421 * Remember that there is a size limit of 100 kB per message on the
5422 u-boot mailing list. Bigger patches will be moderated. If they are
5423 reasonable and not too big, they will be acknowledged. But patches
5424 bigger than the size limit should be avoided.