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_PCMCIA * PCMCIA support
816 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
818 CONFIG_CMD_PORTIO * Port I/O
819 CONFIG_CMD_READ * Read raw data from partition
820 CONFIG_CMD_REGINFO * Register dump
821 CONFIG_CMD_RUN run command in env variable
822 CONFIG_CMD_SANDBOX * sb command to access sandbox features
823 CONFIG_CMD_SAVES * save S record dump
824 CONFIG_CMD_SDRAM * print SDRAM configuration information
825 (requires CONFIG_CMD_I2C)
826 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
827 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
828 CONFIG_CMD_SOURCE "source" command Support
829 CONFIG_CMD_SPI * SPI serial bus support
830 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
831 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
832 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
833 CONFIG_CMD_TIMER * access to the system tick timer
834 CONFIG_CMD_USB * USB support
835 CONFIG_CMD_CDP * Cisco Discover Protocol support
836 CONFIG_CMD_XIMG Load part of Multi Image
837 CONFIG_CMD_UUID * Generate random UUID or GUID string
839 EXAMPLE: If you want all functions except of network
840 support you can write:
842 #include "config_cmd_all.h"
843 #undef CONFIG_CMD_NET
846 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
848 Note: Don't enable the "icache" and "dcache" commands
849 (configuration option CONFIG_CMD_CACHE) unless you know
850 what you (and your U-Boot users) are doing. Data
851 cache cannot be enabled on systems like the
852 8xx (where accesses to the IMMR region must be
853 uncached), and it cannot be disabled on all other
854 systems where we (mis-) use the data cache to hold an
855 initial stack and some data.
858 XXX - this list needs to get updated!
860 - Removal of commands
861 If no commands are needed to boot, you can disable
862 CONFIG_CMDLINE to remove them. In this case, the command line
863 will not be available, and when U-Boot wants to execute the
864 boot command (on start-up) it will call board_run_command()
865 instead. This can reduce image size significantly for very
866 simple boot procedures.
868 - Regular expression support:
870 If this variable is defined, U-Boot is linked against
871 the SLRE (Super Light Regular Expression) library,
872 which adds regex support to some commands, as for
873 example "env grep" and "setexpr".
877 If this variable is defined, U-Boot will use a device tree
878 to configure its devices, instead of relying on statically
879 compiled #defines in the board file. This option is
880 experimental and only available on a few boards. The device
881 tree is available in the global data as gd->fdt_blob.
883 U-Boot needs to get its device tree from somewhere. This can
884 be done using one of the three options below:
887 If this variable is defined, U-Boot will embed a device tree
888 binary in its image. This device tree file should be in the
889 board directory and called <soc>-<board>.dts. The binary file
890 is then picked up in board_init_f() and made available through
891 the global data structure as gd->blob.
894 If this variable is defined, U-Boot will build a device tree
895 binary. It will be called u-boot.dtb. Architecture-specific
896 code will locate it at run-time. Generally this works by:
898 cat u-boot.bin u-boot.dtb >image.bin
900 and in fact, U-Boot does this for you, creating a file called
901 u-boot-dtb.bin which is useful in the common case. You can
902 still use the individual files if you need something more
906 If this variable is defined, U-Boot will use the device tree
907 provided by the board at runtime instead of embedding one with
908 the image. Only boards defining board_fdt_blob_setup() support
909 this option (see include/fdtdec.h file).
913 If this variable is defined, it enables watchdog
914 support for the SoC. There must be support in the SoC
915 specific code for a watchdog. For the 8xx
916 CPUs, the SIU Watchdog feature is enabled in the SYPCR
917 register. When supported for a specific SoC is
918 available, then no further board specific code should
922 When using a watchdog circuitry external to the used
923 SoC, then define this variable and provide board
924 specific code for the "hw_watchdog_reset" function.
926 CONFIG_AT91_HW_WDT_TIMEOUT
927 specify the timeout in seconds. default 2 seconds.
930 CONFIG_VERSION_VARIABLE
931 If this variable is defined, an environment variable
932 named "ver" is created by U-Boot showing the U-Boot
933 version as printed by the "version" command.
934 Any change to this variable will be reverted at the
939 When CONFIG_CMD_DATE is selected, the type of the RTC
940 has to be selected, too. Define exactly one of the
943 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
944 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
945 CONFIG_RTC_MC146818 - use MC146818 RTC
946 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
947 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
948 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
949 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
950 CONFIG_RTC_DS164x - use Dallas DS164x RTC
951 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
952 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
953 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
954 CONFIG_SYS_RV3029_TCR - enable trickle charger on
957 Note that if the RTC uses I2C, then the I2C interface
958 must also be configured. See I2C Support, below.
961 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
963 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
964 chip-ngpio pairs that tell the PCA953X driver the number of
965 pins supported by a particular chip.
967 Note that if the GPIO device uses I2C, then the I2C interface
968 must also be configured. See I2C Support, below.
971 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
972 accesses and can checksum them or write a list of them out
973 to memory. See the 'iotrace' command for details. This is
974 useful for testing device drivers since it can confirm that
975 the driver behaves the same way before and after a code
976 change. Currently this is supported on sandbox and arm. To
977 add support for your architecture, add '#include <iotrace.h>'
978 to the bottom of arch/<arch>/include/asm/io.h and test.
980 Example output from the 'iotrace stats' command is below.
981 Note that if the trace buffer is exhausted, the checksum will
982 still continue to operate.
985 Start: 10000000 (buffer start address)
986 Size: 00010000 (buffer size)
987 Offset: 00000120 (current buffer offset)
988 Output: 10000120 (start + offset)
989 Count: 00000018 (number of trace records)
990 CRC32: 9526fb66 (CRC32 of all trace records)
994 When CONFIG_TIMESTAMP is selected, the timestamp
995 (date and time) of an image is printed by image
996 commands like bootm or iminfo. This option is
997 automatically enabled when you select CONFIG_CMD_DATE .
999 - Partition Labels (disklabels) Supported:
1000 Zero or more of the following:
1001 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1002 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1003 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1004 bootloader. Note 2TB partition limit; see
1006 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1008 If IDE or SCSI support is enabled (CONFIG_IDE or
1009 CONFIG_SCSI) you must configure support for at
1010 least one non-MTD partition type as well.
1013 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1014 board configurations files but used nowhere!
1016 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1017 be performed by calling the function
1018 ide_set_reset(int reset)
1019 which has to be defined in a board specific file
1024 Set this to enable ATAPI support.
1029 Set this to enable support for disks larger than 137GB
1030 Also look at CONFIG_SYS_64BIT_LBA.
1031 Whithout these , LBA48 support uses 32bit variables and will 'only'
1032 support disks up to 2.1TB.
1034 CONFIG_SYS_64BIT_LBA:
1035 When enabled, makes the IDE subsystem use 64bit sector addresses.
1039 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1040 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1041 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1042 maximum numbers of LUNs, SCSI ID's and target
1045 The environment variable 'scsidevs' is set to the number of
1046 SCSI devices found during the last scan.
1048 - NETWORK Support (PCI):
1050 Support for Intel 8254x/8257x gigabit chips.
1053 Utility code for direct access to the SPI bus on Intel 8257x.
1054 This does not do anything useful unless you set at least one
1055 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1057 CONFIG_E1000_SPI_GENERIC
1058 Allow generic access to the SPI bus on the Intel 8257x, for
1059 example with the "sspi" command.
1062 Management command for E1000 devices. When used on devices
1063 with SPI support you can reprogram the EEPROM from U-Boot.
1066 Support for Intel 82557/82559/82559ER chips.
1067 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1068 write routine for first time initialisation.
1071 Support for Digital 2114x chips.
1072 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1073 modem chip initialisation (KS8761/QS6611).
1076 Support for National dp83815 chips.
1079 Support for National dp8382[01] gigabit chips.
1081 - NETWORK Support (other):
1083 CONFIG_DRIVER_AT91EMAC
1084 Support for AT91RM9200 EMAC.
1087 Define this to use reduced MII inteface
1089 CONFIG_DRIVER_AT91EMAC_QUIET
1090 If this defined, the driver is quiet.
1091 The driver doen't show link status messages.
1093 CONFIG_CALXEDA_XGMAC
1094 Support for the Calxeda XGMAC device
1097 Support for SMSC's LAN91C96 chips.
1099 CONFIG_LAN91C96_USE_32_BIT
1100 Define this to enable 32 bit addressing
1103 Support for SMSC's LAN91C111 chip
1105 CONFIG_SMC91111_BASE
1106 Define this to hold the physical address
1107 of the device (I/O space)
1109 CONFIG_SMC_USE_32_BIT
1110 Define this if data bus is 32 bits
1112 CONFIG_SMC_USE_IOFUNCS
1113 Define this to use i/o functions instead of macros
1114 (some hardware wont work with macros)
1116 CONFIG_DRIVER_TI_EMAC
1117 Support for davinci emac
1119 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1120 Define this if you have more then 3 PHYs.
1123 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1125 CONFIG_FTGMAC100_EGIGA
1126 Define this to use GE link update with gigabit PHY.
1127 Define this if FTGMAC100 is connected to gigabit PHY.
1128 If your system has 10/100 PHY only, it might not occur
1129 wrong behavior. Because PHY usually return timeout or
1130 useless data when polling gigabit status and gigabit
1131 control registers. This behavior won't affect the
1132 correctnessof 10/100 link speed update.
1135 Support for SMSC's LAN911x and LAN921x chips
1138 Define this to hold the physical address
1139 of the device (I/O space)
1141 CONFIG_SMC911X_32_BIT
1142 Define this if data bus is 32 bits
1144 CONFIG_SMC911X_16_BIT
1145 Define this if data bus is 16 bits. If your processor
1146 automatically converts one 32 bit word to two 16 bit
1147 words you may also try CONFIG_SMC911X_32_BIT.
1150 Support for Renesas on-chip Ethernet controller
1152 CONFIG_SH_ETHER_USE_PORT
1153 Define the number of ports to be used
1155 CONFIG_SH_ETHER_PHY_ADDR
1156 Define the ETH PHY's address
1158 CONFIG_SH_ETHER_CACHE_WRITEBACK
1159 If this option is set, the driver enables cache flush.
1163 Support for PWM module on the imx6.
1167 Support TPM devices.
1169 CONFIG_TPM_TIS_INFINEON
1170 Support for Infineon i2c bus TPM devices. Only one device
1171 per system is supported at this time.
1173 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1174 Define the burst count bytes upper limit
1177 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1179 CONFIG_TPM_ST33ZP24_I2C
1180 Support for STMicroelectronics ST33ZP24 I2C devices.
1181 Requires TPM_ST33ZP24 and I2C.
1183 CONFIG_TPM_ST33ZP24_SPI
1184 Support for STMicroelectronics ST33ZP24 SPI devices.
1185 Requires TPM_ST33ZP24 and SPI.
1187 CONFIG_TPM_ATMEL_TWI
1188 Support for Atmel TWI TPM device. Requires I2C support.
1191 Support for generic parallel port TPM devices. Only one device
1192 per system is supported at this time.
1194 CONFIG_TPM_TIS_BASE_ADDRESS
1195 Base address where the generic TPM device is mapped
1196 to. Contemporary x86 systems usually map it at
1200 Add tpm monitor functions.
1201 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1202 provides monitor access to authorized functions.
1205 Define this to enable the TPM support library which provides
1206 functional interfaces to some TPM commands.
1207 Requires support for a TPM device.
1209 CONFIG_TPM_AUTH_SESSIONS
1210 Define this to enable authorized functions in the TPM library.
1211 Requires CONFIG_TPM and CONFIG_SHA1.
1214 At the moment only the UHCI host controller is
1215 supported (PIP405, MIP405); define
1216 CONFIG_USB_UHCI to enable it.
1217 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1218 and define CONFIG_USB_STORAGE to enable the USB
1221 Supported are USB Keyboards and USB Floppy drives
1224 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1225 txfilltuning field in the EHCI controller on reset.
1227 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1228 HW module registers.
1231 Define the below if you wish to use the USB console.
1232 Once firmware is rebuilt from a serial console issue the
1233 command "setenv stdin usbtty; setenv stdout usbtty" and
1234 attach your USB cable. The Unix command "dmesg" should print
1235 it has found a new device. The environment variable usbtty
1236 can be set to gserial or cdc_acm to enable your device to
1237 appear to a USB host as a Linux gserial device or a
1238 Common Device Class Abstract Control Model serial device.
1239 If you select usbtty = gserial you should be able to enumerate
1241 # modprobe usbserial vendor=0xVendorID product=0xProductID
1242 else if using cdc_acm, simply setting the environment
1243 variable usbtty to be cdc_acm should suffice. The following
1244 might be defined in YourBoardName.h
1247 Define this to build a UDC device
1250 Define this to have a tty type of device available to
1251 talk to the UDC device
1254 Define this to enable the high speed support for usb
1255 device and usbtty. If this feature is enabled, a routine
1256 int is_usbd_high_speed(void)
1257 also needs to be defined by the driver to dynamically poll
1258 whether the enumeration has succeded at high speed or full
1261 CONFIG_SYS_CONSOLE_IS_IN_ENV
1262 Define this if you want stdin, stdout &/or stderr to
1265 If you have a USB-IF assigned VendorID then you may wish to
1266 define your own vendor specific values either in BoardName.h
1267 or directly in usbd_vendor_info.h. If you don't define
1268 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1269 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1270 should pretend to be a Linux device to it's target host.
1272 CONFIG_USBD_MANUFACTURER
1273 Define this string as the name of your company for
1274 - CONFIG_USBD_MANUFACTURER "my company"
1276 CONFIG_USBD_PRODUCT_NAME
1277 Define this string as the name of your product
1278 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1280 CONFIG_USBD_VENDORID
1281 Define this as your assigned Vendor ID from the USB
1282 Implementors Forum. This *must* be a genuine Vendor ID
1283 to avoid polluting the USB namespace.
1284 - CONFIG_USBD_VENDORID 0xFFFF
1286 CONFIG_USBD_PRODUCTID
1287 Define this as the unique Product ID
1289 - CONFIG_USBD_PRODUCTID 0xFFFF
1291 - ULPI Layer Support:
1292 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1293 the generic ULPI layer. The generic layer accesses the ULPI PHY
1294 via the platform viewport, so you need both the genric layer and
1295 the viewport enabled. Currently only Chipidea/ARC based
1296 viewport is supported.
1297 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1298 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1299 If your ULPI phy needs a different reference clock than the
1300 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1301 the appropriate value in Hz.
1304 The MMC controller on the Intel PXA is supported. To
1305 enable this define CONFIG_MMC. The MMC can be
1306 accessed from the boot prompt by mapping the device
1307 to physical memory similar to flash. Command line is
1308 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1309 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1312 Support for Renesas on-chip MMCIF controller
1314 CONFIG_SH_MMCIF_ADDR
1315 Define the base address of MMCIF registers
1318 Define the clock frequency for MMCIF
1320 CONFIG_SUPPORT_EMMC_BOOT
1321 Enable some additional features of the eMMC boot partitions.
1323 CONFIG_SUPPORT_EMMC_RPMB
1324 Enable the commands for reading, writing and programming the
1325 key for the Replay Protection Memory Block partition in eMMC.
1327 - USB Device Firmware Update (DFU) class support:
1328 CONFIG_USB_FUNCTION_DFU
1329 This enables the USB portion of the DFU USB class
1332 This enables the command "dfu" which is used to have
1333 U-Boot create a DFU class device via USB. This command
1334 requires that the "dfu_alt_info" environment variable be
1335 set and define the alt settings to expose to the host.
1338 This enables support for exposing (e)MMC devices via DFU.
1341 This enables support for exposing NAND devices via DFU.
1344 This enables support for exposing RAM via DFU.
1345 Note: DFU spec refer to non-volatile memory usage, but
1346 allow usages beyond the scope of spec - here RAM usage,
1347 one that would help mostly the developer.
1349 CONFIG_SYS_DFU_DATA_BUF_SIZE
1350 Dfu transfer uses a buffer before writing data to the
1351 raw storage device. Make the size (in bytes) of this buffer
1352 configurable. The size of this buffer is also configurable
1353 through the "dfu_bufsiz" environment variable.
1355 CONFIG_SYS_DFU_MAX_FILE_SIZE
1356 When updating files rather than the raw storage device,
1357 we use a static buffer to copy the file into and then write
1358 the buffer once we've been given the whole file. Define
1359 this to the maximum filesize (in bytes) for the buffer.
1360 Default is 4 MiB if undefined.
1362 DFU_DEFAULT_POLL_TIMEOUT
1363 Poll timeout [ms], is the timeout a device can send to the
1364 host. The host must wait for this timeout before sending
1365 a subsequent DFU_GET_STATUS request to the device.
1367 DFU_MANIFEST_POLL_TIMEOUT
1368 Poll timeout [ms], which the device sends to the host when
1369 entering dfuMANIFEST state. Host waits this timeout, before
1370 sending again an USB request to the device.
1372 - USB Device Android Fastboot support:
1373 CONFIG_USB_FUNCTION_FASTBOOT
1374 This enables the USB part of the fastboot gadget
1377 This enables the command "fastboot" which enables the Android
1378 fastboot mode for the platform's USB device. Fastboot is a USB
1379 protocol for downloading images, flashing and device control
1380 used on Android devices.
1381 See doc/README.android-fastboot for more information.
1383 CONFIG_ANDROID_BOOT_IMAGE
1384 This enables support for booting images which use the Android
1385 image format header.
1387 CONFIG_FASTBOOT_BUF_ADDR
1388 The fastboot protocol requires a large memory buffer for
1389 downloads. Define this to the starting RAM address to use for
1392 CONFIG_FASTBOOT_BUF_SIZE
1393 The fastboot protocol requires a large memory buffer for
1394 downloads. This buffer should be as large as possible for a
1395 platform. Define this to the size available RAM for fastboot.
1397 CONFIG_FASTBOOT_FLASH
1398 The fastboot protocol includes a "flash" command for writing
1399 the downloaded image to a non-volatile storage device. Define
1400 this to enable the "fastboot flash" command.
1402 CONFIG_FASTBOOT_FLASH_MMC_DEV
1403 The fastboot "flash" command requires additional information
1404 regarding the non-volatile storage device. Define this to
1405 the eMMC device that fastboot should use to store the image.
1407 CONFIG_FASTBOOT_GPT_NAME
1408 The fastboot "flash" command supports writing the downloaded
1409 image to the Protective MBR and the Primary GUID Partition
1410 Table. (Additionally, this downloaded image is post-processed
1411 to generate and write the Backup GUID Partition Table.)
1412 This occurs when the specified "partition name" on the
1413 "fastboot flash" command line matches this value.
1414 The default is "gpt" if undefined.
1416 CONFIG_FASTBOOT_MBR_NAME
1417 The fastboot "flash" command supports writing the downloaded
1419 This occurs when the "partition name" specified on the
1420 "fastboot flash" command line matches this value.
1421 If not defined the default value "mbr" is used.
1423 - Journaling Flash filesystem support:
1425 Define these for a default partition on a NAND device
1427 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1428 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1429 Define these for a default partition on a NOR device
1432 See Kconfig help for available keyboard drivers.
1436 Define this to enable a custom keyboard support.
1437 This simply calls drv_keyboard_init() which must be
1438 defined in your board-specific files. This option is deprecated
1439 and is only used by novena. For new boards, use driver model
1444 Enable the Freescale DIU video driver. Reference boards for
1445 SOCs that have a DIU should define this macro to enable DIU
1446 support, and should also define these other macros:
1451 CONFIG_VIDEO_SW_CURSOR
1452 CONFIG_VGA_AS_SINGLE_DEVICE
1454 CONFIG_VIDEO_BMP_LOGO
1456 The DIU driver will look for the 'video-mode' environment
1457 variable, and if defined, enable the DIU as a console during
1458 boot. See the documentation file doc/README.video for a
1459 description of this variable.
1461 - LCD Support: CONFIG_LCD
1463 Define this to enable LCD support (for output to LCD
1464 display); also select one of the supported displays
1465 by defining one of these:
1469 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1471 CONFIG_NEC_NL6448AC33:
1473 NEC NL6448AC33-18. Active, color, single scan.
1475 CONFIG_NEC_NL6448BC20
1477 NEC NL6448BC20-08. 6.5", 640x480.
1478 Active, color, single scan.
1480 CONFIG_NEC_NL6448BC33_54
1482 NEC NL6448BC33-54. 10.4", 640x480.
1483 Active, color, single scan.
1487 Sharp 320x240. Active, color, single scan.
1488 It isn't 16x9, and I am not sure what it is.
1490 CONFIG_SHARP_LQ64D341
1492 Sharp LQ64D341 display, 640x480.
1493 Active, color, single scan.
1497 HLD1045 display, 640x480.
1498 Active, color, single scan.
1502 Optrex CBL50840-2 NF-FW 99 22 M5
1504 Hitachi LMG6912RPFC-00T
1508 320x240. Black & white.
1510 CONFIG_LCD_ALIGNMENT
1512 Normally the LCD is page-aligned (typically 4KB). If this is
1513 defined then the LCD will be aligned to this value instead.
1514 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1515 here, since it is cheaper to change data cache settings on
1516 a per-section basis.
1521 Sometimes, for example if the display is mounted in portrait
1522 mode or even if it's mounted landscape but rotated by 180degree,
1523 we need to rotate our content of the display relative to the
1524 framebuffer, so that user can read the messages which are
1526 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1527 initialized with a given rotation from "vl_rot" out of
1528 "vidinfo_t" which is provided by the board specific code.
1529 The value for vl_rot is coded as following (matching to
1530 fbcon=rotate:<n> linux-kernel commandline):
1531 0 = no rotation respectively 0 degree
1532 1 = 90 degree rotation
1533 2 = 180 degree rotation
1534 3 = 270 degree rotation
1536 If CONFIG_LCD_ROTATION is not defined, the console will be
1537 initialized with 0degree rotation.
1541 Support drawing of RLE8-compressed bitmaps on the LCD.
1545 Enables an 'i2c edid' command which can read EDID
1546 information over I2C from an attached LCD display.
1548 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1550 If this option is set, the environment is checked for
1551 a variable "splashimage". If found, the usual display
1552 of logo, copyright and system information on the LCD
1553 is suppressed and the BMP image at the address
1554 specified in "splashimage" is loaded instead. The
1555 console is redirected to the "nulldev", too. This
1556 allows for a "silent" boot where a splash screen is
1557 loaded very quickly after power-on.
1559 CONFIG_SPLASHIMAGE_GUARD
1561 If this option is set, then U-Boot will prevent the environment
1562 variable "splashimage" from being set to a problematic address
1563 (see doc/README.displaying-bmps).
1564 This option is useful for targets where, due to alignment
1565 restrictions, an improperly aligned BMP image will cause a data
1566 abort. If you think you will not have problems with unaligned
1567 accesses (for example because your toolchain prevents them)
1568 there is no need to set this option.
1570 CONFIG_SPLASH_SCREEN_ALIGN
1572 If this option is set the splash image can be freely positioned
1573 on the screen. Environment variable "splashpos" specifies the
1574 position as "x,y". If a positive number is given it is used as
1575 number of pixel from left/top. If a negative number is given it
1576 is used as number of pixel from right/bottom. You can also
1577 specify 'm' for centering the image.
1580 setenv splashpos m,m
1581 => image at center of screen
1583 setenv splashpos 30,20
1584 => image at x = 30 and y = 20
1586 setenv splashpos -10,m
1587 => vertically centered image
1588 at x = dspWidth - bmpWidth - 9
1590 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1592 If this option is set, additionally to standard BMP
1593 images, gzipped BMP images can be displayed via the
1594 splashscreen support or the bmp command.
1596 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1598 If this option is set, 8-bit RLE compressed BMP images
1599 can be displayed via the splashscreen support or the
1602 - Compression support:
1605 Enabled by default to support gzip compressed images.
1609 If this option is set, support for bzip2 compressed
1610 images is included. If not, only uncompressed and gzip
1611 compressed images are supported.
1613 NOTE: the bzip2 algorithm requires a lot of RAM, so
1614 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1620 The address of PHY on MII bus.
1622 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1624 The clock frequency of the MII bus
1626 CONFIG_PHY_RESET_DELAY
1628 Some PHY like Intel LXT971A need extra delay after
1629 reset before any MII register access is possible.
1630 For such PHY, set this option to the usec delay
1631 required. (minimum 300usec for LXT971A)
1633 CONFIG_PHY_CMD_DELAY (ppc4xx)
1635 Some PHY like Intel LXT971A need extra delay after
1636 command issued before MII status register can be read
1641 Define a default value for the IP address to use for
1642 the default Ethernet interface, in case this is not
1643 determined through e.g. bootp.
1644 (Environment variable "ipaddr")
1646 - Server IP address:
1649 Defines a default value for the IP address of a TFTP
1650 server to contact when using the "tftboot" command.
1651 (Environment variable "serverip")
1653 CONFIG_KEEP_SERVERADDR
1655 Keeps the server's MAC address, in the env 'serveraddr'
1656 for passing to bootargs (like Linux's netconsole option)
1658 - Gateway IP address:
1661 Defines a default value for the IP address of the
1662 default router where packets to other networks are
1664 (Environment variable "gatewayip")
1669 Defines a default value for the subnet mask (or
1670 routing prefix) which is used to determine if an IP
1671 address belongs to the local subnet or needs to be
1672 forwarded through a router.
1673 (Environment variable "netmask")
1675 - Multicast TFTP Mode:
1678 Defines whether you want to support multicast TFTP as per
1679 rfc-2090; for example to work with atftp. Lets lots of targets
1680 tftp down the same boot image concurrently. Note: the Ethernet
1681 driver in use must provide a function: mcast() to join/leave a
1684 - BOOTP Recovery Mode:
1685 CONFIG_BOOTP_RANDOM_DELAY
1687 If you have many targets in a network that try to
1688 boot using BOOTP, you may want to avoid that all
1689 systems send out BOOTP requests at precisely the same
1690 moment (which would happen for instance at recovery
1691 from a power failure, when all systems will try to
1692 boot, thus flooding the BOOTP server. Defining
1693 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1694 inserted before sending out BOOTP requests. The
1695 following delays are inserted then:
1697 1st BOOTP request: delay 0 ... 1 sec
1698 2nd BOOTP request: delay 0 ... 2 sec
1699 3rd BOOTP request: delay 0 ... 4 sec
1701 BOOTP requests: delay 0 ... 8 sec
1703 CONFIG_BOOTP_ID_CACHE_SIZE
1705 BOOTP packets are uniquely identified using a 32-bit ID. The
1706 server will copy the ID from client requests to responses and
1707 U-Boot will use this to determine if it is the destination of
1708 an incoming response. Some servers will check that addresses
1709 aren't in use before handing them out (usually using an ARP
1710 ping) and therefore take up to a few hundred milliseconds to
1711 respond. Network congestion may also influence the time it
1712 takes for a response to make it back to the client. If that
1713 time is too long, U-Boot will retransmit requests. In order
1714 to allow earlier responses to still be accepted after these
1715 retransmissions, U-Boot's BOOTP client keeps a small cache of
1716 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1717 cache. The default is to keep IDs for up to four outstanding
1718 requests. Increasing this will allow U-Boot to accept offers
1719 from a BOOTP client in networks with unusually high latency.
1721 - DHCP Advanced Options:
1722 You can fine tune the DHCP functionality by defining
1723 CONFIG_BOOTP_* symbols:
1725 CONFIG_BOOTP_SUBNETMASK
1726 CONFIG_BOOTP_GATEWAY
1727 CONFIG_BOOTP_HOSTNAME
1728 CONFIG_BOOTP_NISDOMAIN
1729 CONFIG_BOOTP_BOOTPATH
1730 CONFIG_BOOTP_BOOTFILESIZE
1733 CONFIG_BOOTP_SEND_HOSTNAME
1734 CONFIG_BOOTP_NTPSERVER
1735 CONFIG_BOOTP_TIMEOFFSET
1736 CONFIG_BOOTP_VENDOREX
1737 CONFIG_BOOTP_MAY_FAIL
1739 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1740 environment variable, not the BOOTP server.
1742 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1743 after the configured retry count, the call will fail
1744 instead of starting over. This can be used to fail over
1745 to Link-local IP address configuration if the DHCP server
1748 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1749 serverip from a DHCP server, it is possible that more
1750 than one DNS serverip is offered to the client.
1751 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1752 serverip will be stored in the additional environment
1753 variable "dnsip2". The first DNS serverip is always
1754 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1757 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1758 to do a dynamic update of a DNS server. To do this, they
1759 need the hostname of the DHCP requester.
1760 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1761 of the "hostname" environment variable is passed as
1762 option 12 to the DHCP server.
1764 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1766 A 32bit value in microseconds for a delay between
1767 receiving a "DHCP Offer" and sending the "DHCP Request".
1768 This fixes a problem with certain DHCP servers that don't
1769 respond 100% of the time to a "DHCP request". E.g. On an
1770 AT91RM9200 processor running at 180MHz, this delay needed
1771 to be *at least* 15,000 usec before a Windows Server 2003
1772 DHCP server would reply 100% of the time. I recommend at
1773 least 50,000 usec to be safe. The alternative is to hope
1774 that one of the retries will be successful but note that
1775 the DHCP timeout and retry process takes a longer than
1778 - Link-local IP address negotiation:
1779 Negotiate with other link-local clients on the local network
1780 for an address that doesn't require explicit configuration.
1781 This is especially useful if a DHCP server cannot be guaranteed
1782 to exist in all environments that the device must operate.
1784 See doc/README.link-local for more information.
1787 CONFIG_CDP_DEVICE_ID
1789 The device id used in CDP trigger frames.
1791 CONFIG_CDP_DEVICE_ID_PREFIX
1793 A two character string which is prefixed to the MAC address
1798 A printf format string which contains the ascii name of
1799 the port. Normally is set to "eth%d" which sets
1800 eth0 for the first Ethernet, eth1 for the second etc.
1802 CONFIG_CDP_CAPABILITIES
1804 A 32bit integer which indicates the device capabilities;
1805 0x00000010 for a normal host which does not forwards.
1809 An ascii string containing the version of the software.
1813 An ascii string containing the name of the platform.
1817 A 32bit integer sent on the trigger.
1819 CONFIG_CDP_POWER_CONSUMPTION
1821 A 16bit integer containing the power consumption of the
1822 device in .1 of milliwatts.
1824 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1826 A byte containing the id of the VLAN.
1828 - Status LED: CONFIG_LED_STATUS
1830 Several configurations allow to display the current
1831 status using a LED. For instance, the LED will blink
1832 fast while running U-Boot code, stop blinking as
1833 soon as a reply to a BOOTP request was received, and
1834 start blinking slow once the Linux kernel is running
1835 (supported by a status LED driver in the Linux
1836 kernel). Defining CONFIG_LED_STATUS enables this
1841 CONFIG_LED_STATUS_GPIO
1842 The status LED can be connected to a GPIO pin.
1843 In such cases, the gpio_led driver can be used as a
1844 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1845 to include the gpio_led driver in the U-Boot binary.
1847 CONFIG_GPIO_LED_INVERTED_TABLE
1848 Some GPIO connected LEDs may have inverted polarity in which
1849 case the GPIO high value corresponds to LED off state and
1850 GPIO low value corresponds to LED on state.
1851 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1852 with a list of GPIO LEDs that have inverted polarity.
1854 - I2C Support: CONFIG_SYS_I2C
1856 This enable the NEW i2c subsystem, and will allow you to use
1857 i2c commands at the u-boot command line (as long as you set
1858 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1859 based realtime clock chips or other i2c devices. See
1860 common/cmd_i2c.c for a description of the command line
1863 ported i2c driver to the new framework:
1864 - drivers/i2c/soft_i2c.c:
1865 - activate first bus with CONFIG_SYS_I2C_SOFT define
1866 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1867 for defining speed and slave address
1868 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1869 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1870 for defining speed and slave address
1871 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1872 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1873 for defining speed and slave address
1874 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1875 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1876 for defining speed and slave address
1878 - drivers/i2c/fsl_i2c.c:
1879 - activate i2c driver with CONFIG_SYS_I2C_FSL
1880 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1881 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1882 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1884 - If your board supports a second fsl i2c bus, define
1885 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1886 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1887 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1890 - drivers/i2c/tegra_i2c.c:
1891 - activate this driver with CONFIG_SYS_I2C_TEGRA
1892 - This driver adds 4 i2c buses with a fix speed from
1893 100000 and the slave addr 0!
1895 - drivers/i2c/ppc4xx_i2c.c
1896 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1897 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1898 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1900 - drivers/i2c/i2c_mxc.c
1901 - activate this driver with CONFIG_SYS_I2C_MXC
1902 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1903 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1904 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1905 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1906 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1907 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1908 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1909 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1910 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1911 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1912 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1913 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1914 If those defines are not set, default value is 100000
1915 for speed, and 0 for slave.
1917 - drivers/i2c/rcar_i2c.c:
1918 - activate this driver with CONFIG_SYS_I2C_RCAR
1919 - This driver adds 4 i2c buses
1921 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1922 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1923 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1924 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1925 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1926 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1927 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1928 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1929 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1931 - drivers/i2c/sh_i2c.c:
1932 - activate this driver with CONFIG_SYS_I2C_SH
1933 - This driver adds from 2 to 5 i2c buses
1935 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1936 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1937 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1938 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1939 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1940 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1941 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1942 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1943 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1944 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1945 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1947 - drivers/i2c/omap24xx_i2c.c
1948 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1949 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1950 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1951 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1952 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1953 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1954 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1955 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1956 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1957 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1958 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1960 - drivers/i2c/zynq_i2c.c
1961 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1962 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1963 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1965 - drivers/i2c/s3c24x0_i2c.c:
1966 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1967 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1968 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1969 with a fix speed from 100000 and the slave addr 0!
1971 - drivers/i2c/ihs_i2c.c
1972 - activate this driver with CONFIG_SYS_I2C_IHS
1973 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1974 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1975 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1976 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1977 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1978 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1979 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1980 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1981 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1982 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1983 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1984 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1985 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1986 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1987 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1988 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1989 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1990 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1991 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1992 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1993 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1997 CONFIG_SYS_NUM_I2C_BUSES
1998 Hold the number of i2c buses you want to use.
2000 CONFIG_SYS_I2C_DIRECT_BUS
2001 define this, if you don't use i2c muxes on your hardware.
2002 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2005 CONFIG_SYS_I2C_MAX_HOPS
2006 define how many muxes are maximal consecutively connected
2007 on one i2c bus. If you not use i2c muxes, omit this
2010 CONFIG_SYS_I2C_BUSES
2011 hold a list of buses you want to use, only used if
2012 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2013 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2014 CONFIG_SYS_NUM_I2C_BUSES = 9:
2016 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2017 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2018 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2019 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2020 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2021 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2022 {1, {I2C_NULL_HOP}}, \
2023 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2024 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2028 bus 0 on adapter 0 without a mux
2029 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2030 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2031 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2032 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2033 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2034 bus 6 on adapter 1 without a mux
2035 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2036 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2038 If you do not have i2c muxes on your board, omit this define.
2040 - Legacy I2C Support:
2041 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2042 then the following macros need to be defined (examples are
2043 from include/configs/lwmon.h):
2047 (Optional). Any commands necessary to enable the I2C
2048 controller or configure ports.
2050 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2054 The code necessary to make the I2C data line active
2055 (driven). If the data line is open collector, this
2058 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2062 The code necessary to make the I2C data line tri-stated
2063 (inactive). If the data line is open collector, this
2066 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2070 Code that returns true if the I2C data line is high,
2073 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2077 If <bit> is true, sets the I2C data line high. If it
2078 is false, it clears it (low).
2080 eg: #define I2C_SDA(bit) \
2081 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2082 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2086 If <bit> is true, sets the I2C clock line high. If it
2087 is false, it clears it (low).
2089 eg: #define I2C_SCL(bit) \
2090 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2091 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2095 This delay is invoked four times per clock cycle so this
2096 controls the rate of data transfer. The data rate thus
2097 is 1 / (I2C_DELAY * 4). Often defined to be something
2100 #define I2C_DELAY udelay(2)
2102 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2104 If your arch supports the generic GPIO framework (asm/gpio.h),
2105 then you may alternatively define the two GPIOs that are to be
2106 used as SCL / SDA. Any of the previous I2C_xxx macros will
2107 have GPIO-based defaults assigned to them as appropriate.
2109 You should define these to the GPIO value as given directly to
2110 the generic GPIO functions.
2112 CONFIG_SYS_I2C_INIT_BOARD
2114 When a board is reset during an i2c bus transfer
2115 chips might think that the current transfer is still
2116 in progress. On some boards it is possible to access
2117 the i2c SCLK line directly, either by using the
2118 processor pin as a GPIO or by having a second pin
2119 connected to the bus. If this option is defined a
2120 custom i2c_init_board() routine in boards/xxx/board.c
2121 is run early in the boot sequence.
2123 CONFIG_I2C_MULTI_BUS
2125 This option allows the use of multiple I2C buses, each of which
2126 must have a controller. At any point in time, only one bus is
2127 active. To switch to a different bus, use the 'i2c dev' command.
2128 Note that bus numbering is zero-based.
2130 CONFIG_SYS_I2C_NOPROBES
2132 This option specifies a list of I2C devices that will be skipped
2133 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2134 is set, specify a list of bus-device pairs. Otherwise, specify
2135 a 1D array of device addresses
2138 #undef CONFIG_I2C_MULTI_BUS
2139 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2141 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2143 #define CONFIG_I2C_MULTI_BUS
2144 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2146 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2148 CONFIG_SYS_SPD_BUS_NUM
2150 If defined, then this indicates the I2C bus number for DDR SPD.
2151 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2153 CONFIG_SYS_RTC_BUS_NUM
2155 If defined, then this indicates the I2C bus number for the RTC.
2156 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2158 CONFIG_SOFT_I2C_READ_REPEATED_START
2160 defining this will force the i2c_read() function in
2161 the soft_i2c driver to perform an I2C repeated start
2162 between writing the address pointer and reading the
2163 data. If this define is omitted the default behaviour
2164 of doing a stop-start sequence will be used. Most I2C
2165 devices can use either method, but some require one or
2168 - SPI Support: CONFIG_SPI
2170 Enables SPI driver (so far only tested with
2171 SPI EEPROM, also an instance works with Crystal A/D and
2172 D/As on the SACSng board)
2176 Enables the driver for SPI controller on SuperH. Currently
2177 only SH7757 is supported.
2181 Enables a software (bit-bang) SPI driver rather than
2182 using hardware support. This is a general purpose
2183 driver that only requires three general I/O port pins
2184 (two outputs, one input) to function. If this is
2185 defined, the board configuration must define several
2186 SPI configuration items (port pins to use, etc). For
2187 an example, see include/configs/sacsng.h.
2191 Enables a hardware SPI driver for general-purpose reads
2192 and writes. As with CONFIG_SOFT_SPI, the board configuration
2193 must define a list of chip-select function pointers.
2194 Currently supported on some MPC8xxx processors. For an
2195 example, see include/configs/mpc8349emds.h.
2199 Enables the driver for the SPI controllers on i.MX and MXC
2200 SoCs. Currently i.MX31/35/51 are supported.
2202 CONFIG_SYS_SPI_MXC_WAIT
2203 Timeout for waiting until spi transfer completed.
2204 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2206 - FPGA Support: CONFIG_FPGA
2208 Enables FPGA subsystem.
2210 CONFIG_FPGA_<vendor>
2212 Enables support for specific chip vendors.
2215 CONFIG_FPGA_<family>
2217 Enables support for FPGA family.
2218 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2222 Specify the number of FPGA devices to support.
2224 CONFIG_SYS_FPGA_PROG_FEEDBACK
2226 Enable printing of hash marks during FPGA configuration.
2228 CONFIG_SYS_FPGA_CHECK_BUSY
2230 Enable checks on FPGA configuration interface busy
2231 status by the configuration function. This option
2232 will require a board or device specific function to
2237 If defined, a function that provides delays in the FPGA
2238 configuration driver.
2240 CONFIG_SYS_FPGA_CHECK_CTRLC
2241 Allow Control-C to interrupt FPGA configuration
2243 CONFIG_SYS_FPGA_CHECK_ERROR
2245 Check for configuration errors during FPGA bitfile
2246 loading. For example, abort during Virtex II
2247 configuration if the INIT_B line goes low (which
2248 indicated a CRC error).
2250 CONFIG_SYS_FPGA_WAIT_INIT
2252 Maximum time to wait for the INIT_B line to de-assert
2253 after PROB_B has been de-asserted during a Virtex II
2254 FPGA configuration sequence. The default time is 500
2257 CONFIG_SYS_FPGA_WAIT_BUSY
2259 Maximum time to wait for BUSY to de-assert during
2260 Virtex II FPGA configuration. The default is 5 ms.
2262 CONFIG_SYS_FPGA_WAIT_CONFIG
2264 Time to wait after FPGA configuration. The default is
2267 - Configuration Management:
2270 Some SoCs need special image types (e.g. U-Boot binary
2271 with a special header) as build targets. By defining
2272 CONFIG_BUILD_TARGET in the SoC / board header, this
2273 special image will be automatically built upon calling
2278 If defined, this string will be added to the U-Boot
2279 version information (U_BOOT_VERSION)
2281 - Vendor Parameter Protection:
2283 U-Boot considers the values of the environment
2284 variables "serial#" (Board Serial Number) and
2285 "ethaddr" (Ethernet Address) to be parameters that
2286 are set once by the board vendor / manufacturer, and
2287 protects these variables from casual modification by
2288 the user. Once set, these variables are read-only,
2289 and write or delete attempts are rejected. You can
2290 change this behaviour:
2292 If CONFIG_ENV_OVERWRITE is #defined in your config
2293 file, the write protection for vendor parameters is
2294 completely disabled. Anybody can change or delete
2297 Alternatively, if you define _both_ an ethaddr in the
2298 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2299 Ethernet address is installed in the environment,
2300 which can be changed exactly ONCE by the user. [The
2301 serial# is unaffected by this, i. e. it remains
2304 The same can be accomplished in a more flexible way
2305 for any variable by configuring the type of access
2306 to allow for those variables in the ".flags" variable
2307 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2312 Define this variable to enable the reservation of
2313 "protected RAM", i. e. RAM which is not overwritten
2314 by U-Boot. Define CONFIG_PRAM to hold the number of
2315 kB you want to reserve for pRAM. You can overwrite
2316 this default value by defining an environment
2317 variable "pram" to the number of kB you want to
2318 reserve. Note that the board info structure will
2319 still show the full amount of RAM. If pRAM is
2320 reserved, a new environment variable "mem" will
2321 automatically be defined to hold the amount of
2322 remaining RAM in a form that can be passed as boot
2323 argument to Linux, for instance like that:
2325 setenv bootargs ... mem=\${mem}
2328 This way you can tell Linux not to use this memory,
2329 either, which results in a memory region that will
2330 not be affected by reboots.
2332 *WARNING* If your board configuration uses automatic
2333 detection of the RAM size, you must make sure that
2334 this memory test is non-destructive. So far, the
2335 following board configurations are known to be
2338 IVMS8, IVML24, SPD8xx,
2339 HERMES, IP860, RPXlite, LWMON,
2342 - Access to physical memory region (> 4GB)
2343 Some basic support is provided for operations on memory not
2344 normally accessible to U-Boot - e.g. some architectures
2345 support access to more than 4GB of memory on 32-bit
2346 machines using physical address extension or similar.
2347 Define CONFIG_PHYSMEM to access this basic support, which
2348 currently only supports clearing the memory.
2353 Define this variable to stop the system in case of a
2354 fatal error, so that you have to reset it manually.
2355 This is probably NOT a good idea for an embedded
2356 system where you want the system to reboot
2357 automatically as fast as possible, but it may be
2358 useful during development since you can try to debug
2359 the conditions that lead to the situation.
2361 CONFIG_NET_RETRY_COUNT
2363 This variable defines the number of retries for
2364 network operations like ARP, RARP, TFTP, or BOOTP
2365 before giving up the operation. If not defined, a
2366 default value of 5 is used.
2370 Timeout waiting for an ARP reply in milliseconds.
2374 Timeout in milliseconds used in NFS protocol.
2375 If you encounter "ERROR: Cannot umount" in nfs command,
2376 try longer timeout such as
2377 #define CONFIG_NFS_TIMEOUT 10000UL
2379 - Command Interpreter:
2380 CONFIG_AUTO_COMPLETE
2382 Enable auto completion of commands using TAB.
2384 CONFIG_SYS_PROMPT_HUSH_PS2
2386 This defines the secondary prompt string, which is
2387 printed when the command interpreter needs more input
2388 to complete a command. Usually "> ".
2392 In the current implementation, the local variables
2393 space and global environment variables space are
2394 separated. Local variables are those you define by
2395 simply typing `name=value'. To access a local
2396 variable later on, you have write `$name' or
2397 `${name}'; to execute the contents of a variable
2398 directly type `$name' at the command prompt.
2400 Global environment variables are those you use
2401 setenv/printenv to work with. To run a command stored
2402 in such a variable, you need to use the run command,
2403 and you must not use the '$' sign to access them.
2405 To store commands and special characters in a
2406 variable, please use double quotation marks
2407 surrounding the whole text of the variable, instead
2408 of the backslashes before semicolons and special
2411 - Command Line Editing and History:
2412 CONFIG_CMDLINE_EDITING
2414 Enable editing and History functions for interactive
2415 command line input operations
2417 - Command Line PS1/PS2 support:
2418 CONFIG_CMDLINE_PS_SUPPORT
2420 Enable support for changing the command prompt string
2421 at run-time. Only static string is supported so far.
2422 The string is obtained from environment variables PS1
2425 - Default Environment:
2426 CONFIG_EXTRA_ENV_SETTINGS
2428 Define this to contain any number of null terminated
2429 strings (variable = value pairs) that will be part of
2430 the default environment compiled into the boot image.
2432 For example, place something like this in your
2433 board's config file:
2435 #define CONFIG_EXTRA_ENV_SETTINGS \
2439 Warning: This method is based on knowledge about the
2440 internal format how the environment is stored by the
2441 U-Boot code. This is NOT an official, exported
2442 interface! Although it is unlikely that this format
2443 will change soon, there is no guarantee either.
2444 You better know what you are doing here.
2446 Note: overly (ab)use of the default environment is
2447 discouraged. Make sure to check other ways to preset
2448 the environment like the "source" command or the
2451 CONFIG_ENV_VARS_UBOOT_CONFIG
2453 Define this in order to add variables describing the
2454 U-Boot build configuration to the default environment.
2455 These will be named arch, cpu, board, vendor, and soc.
2457 Enabling this option will cause the following to be defined:
2465 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2467 Define this in order to add variables describing certain
2468 run-time determined information about the hardware to the
2469 environment. These will be named board_name, board_rev.
2471 CONFIG_DELAY_ENVIRONMENT
2473 Normally the environment is loaded when the board is
2474 initialised so that it is available to U-Boot. This inhibits
2475 that so that the environment is not available until
2476 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2477 this is instead controlled by the value of
2478 /config/load-environment.
2480 - DataFlash Support:
2481 CONFIG_HAS_DATAFLASH
2483 Defining this option enables DataFlash features and
2484 allows to read/write in Dataflash via the standard
2487 - Serial Flash support
2490 Defining this option enables SPI flash commands
2491 'sf probe/read/write/erase/update'.
2493 Usage requires an initial 'probe' to define the serial
2494 flash parameters, followed by read/write/erase/update
2497 The following defaults may be provided by the platform
2498 to handle the common case when only a single serial
2499 flash is present on the system.
2501 CONFIG_SF_DEFAULT_BUS Bus identifier
2502 CONFIG_SF_DEFAULT_CS Chip-select
2503 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2504 CONFIG_SF_DEFAULT_SPEED in Hz
2508 Define this option to include a destructive SPI flash
2511 - SystemACE Support:
2514 Adding this option adds support for Xilinx SystemACE
2515 chips attached via some sort of local bus. The address
2516 of the chip must also be defined in the
2517 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2519 #define CONFIG_SYSTEMACE
2520 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2522 When SystemACE support is added, the "ace" device type
2523 becomes available to the fat commands, i.e. fatls.
2525 - TFTP Fixed UDP Port:
2528 If this is defined, the environment variable tftpsrcp
2529 is used to supply the TFTP UDP source port value.
2530 If tftpsrcp isn't defined, the normal pseudo-random port
2531 number generator is used.
2533 Also, the environment variable tftpdstp is used to supply
2534 the TFTP UDP destination port value. If tftpdstp isn't
2535 defined, the normal port 69 is used.
2537 The purpose for tftpsrcp is to allow a TFTP server to
2538 blindly start the TFTP transfer using the pre-configured
2539 target IP address and UDP port. This has the effect of
2540 "punching through" the (Windows XP) firewall, allowing
2541 the remainder of the TFTP transfer to proceed normally.
2542 A better solution is to properly configure the firewall,
2543 but sometimes that is not allowed.
2545 - bootcount support:
2546 CONFIG_BOOTCOUNT_LIMIT
2548 This enables the bootcounter support, see:
2549 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2552 enable special bootcounter support on at91sam9xe based boards.
2554 enable special bootcounter support on da850 based boards.
2555 CONFIG_BOOTCOUNT_RAM
2556 enable support for the bootcounter in RAM
2557 CONFIG_BOOTCOUNT_I2C
2558 enable support for the bootcounter on an i2c (like RTC) device.
2559 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2560 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2562 CONFIG_BOOTCOUNT_ALEN = address len
2564 - Show boot progress:
2565 CONFIG_SHOW_BOOT_PROGRESS
2567 Defining this option allows to add some board-
2568 specific code (calling a user-provided function
2569 "show_boot_progress(int)") that enables you to show
2570 the system's boot progress on some display (for
2571 example, some LED's) on your board. At the moment,
2572 the following checkpoints are implemented:
2575 Legacy uImage format:
2578 1 common/cmd_bootm.c before attempting to boot an image
2579 -1 common/cmd_bootm.c Image header has bad magic number
2580 2 common/cmd_bootm.c Image header has correct magic number
2581 -2 common/cmd_bootm.c Image header has bad checksum
2582 3 common/cmd_bootm.c Image header has correct checksum
2583 -3 common/cmd_bootm.c Image data has bad checksum
2584 4 common/cmd_bootm.c Image data has correct checksum
2585 -4 common/cmd_bootm.c Image is for unsupported architecture
2586 5 common/cmd_bootm.c Architecture check OK
2587 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2588 6 common/cmd_bootm.c Image Type check OK
2589 -6 common/cmd_bootm.c gunzip uncompression error
2590 -7 common/cmd_bootm.c Unimplemented compression type
2591 7 common/cmd_bootm.c Uncompression OK
2592 8 common/cmd_bootm.c No uncompress/copy overwrite error
2593 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2595 9 common/image.c Start initial ramdisk verification
2596 -10 common/image.c Ramdisk header has bad magic number
2597 -11 common/image.c Ramdisk header has bad checksum
2598 10 common/image.c Ramdisk header is OK
2599 -12 common/image.c Ramdisk data has bad checksum
2600 11 common/image.c Ramdisk data has correct checksum
2601 12 common/image.c Ramdisk verification complete, start loading
2602 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2603 13 common/image.c Start multifile image verification
2604 14 common/image.c No initial ramdisk, no multifile, continue.
2606 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2608 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2609 -31 post/post.c POST test failed, detected by post_output_backlog()
2610 -32 post/post.c POST test failed, detected by post_run_single()
2612 34 common/cmd_doc.c before loading a Image from a DOC device
2613 -35 common/cmd_doc.c Bad usage of "doc" command
2614 35 common/cmd_doc.c correct usage of "doc" command
2615 -36 common/cmd_doc.c No boot device
2616 36 common/cmd_doc.c correct boot device
2617 -37 common/cmd_doc.c Unknown Chip ID on boot device
2618 37 common/cmd_doc.c correct chip ID found, device available
2619 -38 common/cmd_doc.c Read Error on boot device
2620 38 common/cmd_doc.c reading Image header from DOC device OK
2621 -39 common/cmd_doc.c Image header has bad magic number
2622 39 common/cmd_doc.c Image header has correct magic number
2623 -40 common/cmd_doc.c Error reading Image from DOC device
2624 40 common/cmd_doc.c Image header has correct magic number
2625 41 common/cmd_ide.c before loading a Image from a IDE device
2626 -42 common/cmd_ide.c Bad usage of "ide" command
2627 42 common/cmd_ide.c correct usage of "ide" command
2628 -43 common/cmd_ide.c No boot device
2629 43 common/cmd_ide.c boot device found
2630 -44 common/cmd_ide.c Device not available
2631 44 common/cmd_ide.c Device available
2632 -45 common/cmd_ide.c wrong partition selected
2633 45 common/cmd_ide.c partition selected
2634 -46 common/cmd_ide.c Unknown partition table
2635 46 common/cmd_ide.c valid partition table found
2636 -47 common/cmd_ide.c Invalid partition type
2637 47 common/cmd_ide.c correct partition type
2638 -48 common/cmd_ide.c Error reading Image Header on boot device
2639 48 common/cmd_ide.c reading Image Header from IDE device OK
2640 -49 common/cmd_ide.c Image header has bad magic number
2641 49 common/cmd_ide.c Image header has correct magic number
2642 -50 common/cmd_ide.c Image header has bad checksum
2643 50 common/cmd_ide.c Image header has correct checksum
2644 -51 common/cmd_ide.c Error reading Image from IDE device
2645 51 common/cmd_ide.c reading Image from IDE device OK
2646 52 common/cmd_nand.c before loading a Image from a NAND device
2647 -53 common/cmd_nand.c Bad usage of "nand" command
2648 53 common/cmd_nand.c correct usage of "nand" command
2649 -54 common/cmd_nand.c No boot device
2650 54 common/cmd_nand.c boot device found
2651 -55 common/cmd_nand.c Unknown Chip ID on boot device
2652 55 common/cmd_nand.c correct chip ID found, device available
2653 -56 common/cmd_nand.c Error reading Image Header on boot device
2654 56 common/cmd_nand.c reading Image Header from NAND device OK
2655 -57 common/cmd_nand.c Image header has bad magic number
2656 57 common/cmd_nand.c Image header has correct magic number
2657 -58 common/cmd_nand.c Error reading Image from NAND device
2658 58 common/cmd_nand.c reading Image from NAND device OK
2660 -60 common/env_common.c Environment has a bad CRC, using default
2662 64 net/eth.c starting with Ethernet configuration.
2663 -64 net/eth.c no Ethernet found.
2664 65 net/eth.c Ethernet found.
2666 -80 common/cmd_net.c usage wrong
2667 80 common/cmd_net.c before calling net_loop()
2668 -81 common/cmd_net.c some error in net_loop() occurred
2669 81 common/cmd_net.c net_loop() back without error
2670 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2671 82 common/cmd_net.c trying automatic boot
2672 83 common/cmd_net.c running "source" command
2673 -83 common/cmd_net.c some error in automatic boot or "source" command
2674 84 common/cmd_net.c end without errors
2679 100 common/cmd_bootm.c Kernel FIT Image has correct format
2680 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2681 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2682 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2683 102 common/cmd_bootm.c Kernel unit name specified
2684 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2685 103 common/cmd_bootm.c Found configuration node
2686 104 common/cmd_bootm.c Got kernel subimage node offset
2687 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2688 105 common/cmd_bootm.c Kernel subimage hash verification OK
2689 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2690 106 common/cmd_bootm.c Architecture check OK
2691 -106 common/cmd_bootm.c Kernel subimage has wrong type
2692 107 common/cmd_bootm.c Kernel subimage type OK
2693 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2694 108 common/cmd_bootm.c Got kernel subimage data/size
2695 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2696 -109 common/cmd_bootm.c Can't get kernel subimage type
2697 -110 common/cmd_bootm.c Can't get kernel subimage comp
2698 -111 common/cmd_bootm.c Can't get kernel subimage os
2699 -112 common/cmd_bootm.c Can't get kernel subimage load address
2700 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2702 120 common/image.c Start initial ramdisk verification
2703 -120 common/image.c Ramdisk FIT image has incorrect format
2704 121 common/image.c Ramdisk FIT image has correct format
2705 122 common/image.c No ramdisk subimage unit name, using configuration
2706 -122 common/image.c Can't get configuration for ramdisk subimage
2707 123 common/image.c Ramdisk unit name specified
2708 -124 common/image.c Can't get ramdisk subimage node offset
2709 125 common/image.c Got ramdisk subimage node offset
2710 -125 common/image.c Ramdisk subimage hash verification failed
2711 126 common/image.c Ramdisk subimage hash verification OK
2712 -126 common/image.c Ramdisk subimage for unsupported architecture
2713 127 common/image.c Architecture check OK
2714 -127 common/image.c Can't get ramdisk subimage data/size
2715 128 common/image.c Got ramdisk subimage data/size
2716 129 common/image.c Can't get ramdisk load address
2717 -129 common/image.c Got ramdisk load address
2719 -130 common/cmd_doc.c Incorrect FIT image format
2720 131 common/cmd_doc.c FIT image format OK
2722 -140 common/cmd_ide.c Incorrect FIT image format
2723 141 common/cmd_ide.c FIT image format OK
2725 -150 common/cmd_nand.c Incorrect FIT image format
2726 151 common/cmd_nand.c FIT image format OK
2728 - legacy image format:
2729 CONFIG_IMAGE_FORMAT_LEGACY
2730 enables the legacy image format support in U-Boot.
2733 enabled if CONFIG_FIT_SIGNATURE is not defined.
2735 CONFIG_DISABLE_IMAGE_LEGACY
2736 disable the legacy image format
2738 This define is introduced, as the legacy image format is
2739 enabled per default for backward compatibility.
2741 - Standalone program support:
2742 CONFIG_STANDALONE_LOAD_ADDR
2744 This option defines a board specific value for the
2745 address where standalone program gets loaded, thus
2746 overwriting the architecture dependent default
2749 - Frame Buffer Address:
2752 Define CONFIG_FB_ADDR if you want to use specific
2753 address for frame buffer. This is typically the case
2754 when using a graphics controller has separate video
2755 memory. U-Boot will then place the frame buffer at
2756 the given address instead of dynamically reserving it
2757 in system RAM by calling lcd_setmem(), which grabs
2758 the memory for the frame buffer depending on the
2759 configured panel size.
2761 Please see board_init_f function.
2763 - Automatic software updates via TFTP server
2765 CONFIG_UPDATE_TFTP_CNT_MAX
2766 CONFIG_UPDATE_TFTP_MSEC_MAX
2768 These options enable and control the auto-update feature;
2769 for a more detailed description refer to doc/README.update.
2771 - MTD Support (mtdparts command, UBI support)
2774 Adds the MTD device infrastructure from the Linux kernel.
2775 Needed for mtdparts command support.
2777 CONFIG_MTD_PARTITIONS
2779 Adds the MTD partitioning infrastructure from the Linux
2780 kernel. Needed for UBI support.
2783 CONFIG_UBI_SILENCE_MSG
2785 Make the verbose messages from UBI stop printing. This leaves
2786 warnings and errors enabled.
2789 CONFIG_MTD_UBI_WL_THRESHOLD
2790 This parameter defines the maximum difference between the highest
2791 erase counter value and the lowest erase counter value of eraseblocks
2792 of UBI devices. When this threshold is exceeded, UBI starts performing
2793 wear leveling by means of moving data from eraseblock with low erase
2794 counter to eraseblocks with high erase counter.
2796 The default value should be OK for SLC NAND flashes, NOR flashes and
2797 other flashes which have eraseblock life-cycle 100000 or more.
2798 However, in case of MLC NAND flashes which typically have eraseblock
2799 life-cycle less than 10000, the threshold should be lessened (e.g.,
2800 to 128 or 256, although it does not have to be power of 2).
2804 CONFIG_MTD_UBI_BEB_LIMIT
2805 This option specifies the maximum bad physical eraseblocks UBI
2806 expects on the MTD device (per 1024 eraseblocks). If the
2807 underlying flash does not admit of bad eraseblocks (e.g. NOR
2808 flash), this value is ignored.
2810 NAND datasheets often specify the minimum and maximum NVM
2811 (Number of Valid Blocks) for the flashes' endurance lifetime.
2812 The maximum expected bad eraseblocks per 1024 eraseblocks
2813 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2814 which gives 20 for most NANDs (MaxNVB is basically the total
2815 count of eraseblocks on the chip).
2817 To put it differently, if this value is 20, UBI will try to
2818 reserve about 1.9% of physical eraseblocks for bad blocks
2819 handling. And that will be 1.9% of eraseblocks on the entire
2820 NAND chip, not just the MTD partition UBI attaches. This means
2821 that if you have, say, a NAND flash chip admits maximum 40 bad
2822 eraseblocks, and it is split on two MTD partitions of the same
2823 size, UBI will reserve 40 eraseblocks when attaching a
2828 CONFIG_MTD_UBI_FASTMAP
2829 Fastmap is a mechanism which allows attaching an UBI device
2830 in nearly constant time. Instead of scanning the whole MTD device it
2831 only has to locate a checkpoint (called fastmap) on the device.
2832 The on-flash fastmap contains all information needed to attach
2833 the device. Using fastmap makes only sense on large devices where
2834 attaching by scanning takes long. UBI will not automatically install
2835 a fastmap on old images, but you can set the UBI parameter
2836 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2837 that fastmap-enabled images are still usable with UBI implementations
2838 without fastmap support. On typical flash devices the whole fastmap
2839 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2841 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2842 Set this parameter to enable fastmap automatically on images
2846 CONFIG_MTD_UBI_FM_DEBUG
2847 Enable UBI fastmap debug
2851 CONFIG_UBIFS_SILENCE_MSG
2853 Make the verbose messages from UBIFS stop printing. This leaves
2854 warnings and errors enabled.
2858 Enable building of SPL globally.
2861 LDSCRIPT for linking the SPL binary.
2863 CONFIG_SPL_MAX_FOOTPRINT
2864 Maximum size in memory allocated to the SPL, BSS included.
2865 When defined, the linker checks that the actual memory
2866 used by SPL from _start to __bss_end does not exceed it.
2867 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2868 must not be both defined at the same time.
2871 Maximum size of the SPL image (text, data, rodata, and
2872 linker lists sections), BSS excluded.
2873 When defined, the linker checks that the actual size does
2876 CONFIG_SPL_TEXT_BASE
2877 TEXT_BASE for linking the SPL binary.
2879 CONFIG_SPL_RELOC_TEXT_BASE
2880 Address to relocate to. If unspecified, this is equal to
2881 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2883 CONFIG_SPL_BSS_START_ADDR
2884 Link address for the BSS within the SPL binary.
2886 CONFIG_SPL_BSS_MAX_SIZE
2887 Maximum size in memory allocated to the SPL BSS.
2888 When defined, the linker checks that the actual memory used
2889 by SPL from __bss_start to __bss_end does not exceed it.
2890 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2891 must not be both defined at the same time.
2894 Adress of the start of the stack SPL will use
2896 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2897 When defined, SPL will panic() if the image it has
2898 loaded does not have a signature.
2899 Defining this is useful when code which loads images
2900 in SPL cannot guarantee that absolutely all read errors
2902 An example is the LPC32XX MLC NAND driver, which will
2903 consider that a completely unreadable NAND block is bad,
2904 and thus should be skipped silently.
2906 CONFIG_SPL_RELOC_STACK
2907 Adress of the start of the stack SPL will use after
2908 relocation. If unspecified, this is equal to
2911 CONFIG_SYS_SPL_MALLOC_START
2912 Starting address of the malloc pool used in SPL.
2913 When this option is set the full malloc is used in SPL and
2914 it is set up by spl_init() and before that, the simple malloc()
2915 can be used if CONFIG_SYS_MALLOC_F is defined.
2917 CONFIG_SYS_SPL_MALLOC_SIZE
2918 The size of the malloc pool used in SPL.
2920 CONFIG_SPL_FRAMEWORK
2921 Enable the SPL framework under common/. This framework
2922 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2923 NAND loading of the Linux Kernel.
2926 Enable booting directly to an OS from SPL.
2927 See also: doc/README.falcon
2929 CONFIG_SPL_DISPLAY_PRINT
2930 For ARM, enable an optional function to print more information
2931 about the running system.
2933 CONFIG_SPL_INIT_MINIMAL
2934 Arch init code should be built for a very small image
2936 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2937 Partition on the MMC to load U-Boot from when the MMC is being
2940 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2941 Sector to load kernel uImage from when MMC is being
2942 used in raw mode (for Falcon mode)
2944 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2945 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2946 Sector and number of sectors to load kernel argument
2947 parameters from when MMC is being used in raw mode
2950 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2951 Partition on the MMC to load U-Boot from when the MMC is being
2954 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2955 Filename to read to load U-Boot when reading from filesystem
2957 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2958 Filename to read to load kernel uImage when reading
2959 from filesystem (for Falcon mode)
2961 CONFIG_SPL_FS_LOAD_ARGS_NAME
2962 Filename to read to load kernel argument parameters
2963 when reading from filesystem (for Falcon mode)
2965 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2966 Set this for NAND SPL on PPC mpc83xx targets, so that
2967 start.S waits for the rest of the SPL to load before
2968 continuing (the hardware starts execution after just
2969 loading the first page rather than the full 4K).
2971 CONFIG_SPL_SKIP_RELOCATE
2972 Avoid SPL relocation
2974 CONFIG_SPL_NAND_BASE
2975 Include nand_base.c in the SPL. Requires
2976 CONFIG_SPL_NAND_DRIVERS.
2978 CONFIG_SPL_NAND_DRIVERS
2979 SPL uses normal NAND drivers, not minimal drivers.
2982 Include standard software ECC in the SPL
2984 CONFIG_SPL_NAND_SIMPLE
2985 Support for NAND boot using simple NAND drivers that
2986 expose the cmd_ctrl() interface.
2989 Support for a lightweight UBI (fastmap) scanner and
2992 CONFIG_SPL_NAND_RAW_ONLY
2993 Support to boot only raw u-boot.bin images. Use this only
2994 if you need to save space.
2996 CONFIG_SPL_COMMON_INIT_DDR
2997 Set for common ddr init with serial presence detect in
3000 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3001 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3002 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3003 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3004 CONFIG_SYS_NAND_ECCBYTES
3005 Defines the size and behavior of the NAND that SPL uses
3008 CONFIG_SPL_NAND_BOOT
3009 Add support NAND boot
3011 CONFIG_SYS_NAND_U_BOOT_OFFS
3012 Location in NAND to read U-Boot from
3014 CONFIG_SYS_NAND_U_BOOT_DST
3015 Location in memory to load U-Boot to
3017 CONFIG_SYS_NAND_U_BOOT_SIZE
3018 Size of image to load
3020 CONFIG_SYS_NAND_U_BOOT_START
3021 Entry point in loaded image to jump to
3023 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3024 Define this if you need to first read the OOB and then the
3025 data. This is used, for example, on davinci platforms.
3027 CONFIG_SPL_OMAP3_ID_NAND
3028 Support for an OMAP3-specific set of functions to return the
3029 ID and MFR of the first attached NAND chip, if present.
3031 CONFIG_SPL_RAM_DEVICE
3032 Support for running image already present in ram, in SPL binary
3035 Image offset to which the SPL should be padded before appending
3036 the SPL payload. By default, this is defined as
3037 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3038 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3039 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3042 Final target image containing SPL and payload. Some SPLs
3043 use an arch-specific makefile fragment instead, for
3044 example if more than one image needs to be produced.
3046 CONFIG_FIT_SPL_PRINT
3047 Printing information about a FIT image adds quite a bit of
3048 code to SPL. So this is normally disabled in SPL. Use this
3049 option to re-enable it. This will affect the output of the
3050 bootm command when booting a FIT image.
3054 Enable building of TPL globally.
3057 Image offset to which the TPL should be padded before appending
3058 the TPL payload. By default, this is defined as
3059 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3060 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3061 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3063 - Interrupt support (PPC):
3065 There are common interrupt_init() and timer_interrupt()
3066 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3067 for CPU specific initialization. interrupt_init_cpu()
3068 should set decrementer_count to appropriate value. If
3069 CPU resets decrementer automatically after interrupt
3070 (ppc4xx) it should set decrementer_count to zero.
3071 timer_interrupt() calls timer_interrupt_cpu() for CPU
3072 specific handling. If board has watchdog / status_led
3073 / other_activity_monitor it works automatically from
3074 general timer_interrupt().
3077 Board initialization settings:
3078 ------------------------------
3080 During Initialization u-boot calls a number of board specific functions
3081 to allow the preparation of board specific prerequisites, e.g. pin setup
3082 before drivers are initialized. To enable these callbacks the
3083 following configuration macros have to be defined. Currently this is
3084 architecture specific, so please check arch/your_architecture/lib/board.c
3085 typically in board_init_f() and board_init_r().
3087 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3088 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3089 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3090 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3092 Configuration Settings:
3093 -----------------------
3095 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3096 Optionally it can be defined to support 64-bit memory commands.
3098 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3099 undefine this when you're short of memory.
3101 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3102 width of the commands listed in the 'help' command output.
3104 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3105 prompt for user input.
3107 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3109 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3111 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3113 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3114 the application (usually a Linux kernel) when it is
3117 - CONFIG_SYS_BAUDRATE_TABLE:
3118 List of legal baudrate settings for this board.
3120 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3121 Begin and End addresses of the area used by the
3124 - CONFIG_SYS_ALT_MEMTEST:
3125 Enable an alternate, more extensive memory test.
3127 - CONFIG_SYS_MEMTEST_SCRATCH:
3128 Scratch address used by the alternate memory test
3129 You only need to set this if address zero isn't writeable
3131 - CONFIG_SYS_MEM_RESERVE_SECURE
3132 Only implemented for ARMv8 for now.
3133 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3134 is substracted from total RAM and won't be reported to OS.
3135 This memory can be used as secure memory. A variable
3136 gd->arch.secure_ram is used to track the location. In systems
3137 the RAM base is not zero, or RAM is divided into banks,
3138 this variable needs to be recalcuated to get the address.
3140 - CONFIG_SYS_MEM_TOP_HIDE:
3141 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3142 this specified memory area will get subtracted from the top
3143 (end) of RAM and won't get "touched" at all by U-Boot. By
3144 fixing up gd->ram_size the Linux kernel should gets passed
3145 the now "corrected" memory size and won't touch it either.
3146 This should work for arch/ppc and arch/powerpc. Only Linux
3147 board ports in arch/powerpc with bootwrapper support that
3148 recalculate the memory size from the SDRAM controller setup
3149 will have to get fixed in Linux additionally.
3151 This option can be used as a workaround for the 440EPx/GRx
3152 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3155 WARNING: Please make sure that this value is a multiple of
3156 the Linux page size (normally 4k). If this is not the case,
3157 then the end address of the Linux memory will be located at a
3158 non page size aligned address and this could cause major
3161 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3162 Enable temporary baudrate change while serial download
3164 - CONFIG_SYS_SDRAM_BASE:
3165 Physical start address of SDRAM. _Must_ be 0 here.
3167 - CONFIG_SYS_FLASH_BASE:
3168 Physical start address of Flash memory.
3170 - CONFIG_SYS_MONITOR_BASE:
3171 Physical start address of boot monitor code (set by
3172 make config files to be same as the text base address
3173 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3174 CONFIG_SYS_FLASH_BASE when booting from flash.
3176 - CONFIG_SYS_MONITOR_LEN:
3177 Size of memory reserved for monitor code, used to
3178 determine _at_compile_time_ (!) if the environment is
3179 embedded within the U-Boot image, or in a separate
3182 - CONFIG_SYS_MALLOC_LEN:
3183 Size of DRAM reserved for malloc() use.
3185 - CONFIG_SYS_MALLOC_F_LEN
3186 Size of the malloc() pool for use before relocation. If
3187 this is defined, then a very simple malloc() implementation
3188 will become available before relocation. The address is just
3189 below the global data, and the stack is moved down to make
3192 This feature allocates regions with increasing addresses
3193 within the region. calloc() is supported, but realloc()
3194 is not available. free() is supported but does nothing.
3195 The memory will be freed (or in fact just forgotten) when
3196 U-Boot relocates itself.
3198 - CONFIG_SYS_MALLOC_SIMPLE
3199 Provides a simple and small malloc() and calloc() for those
3200 boards which do not use the full malloc in SPL (which is
3201 enabled with CONFIG_SYS_SPL_MALLOC_START).
3203 - CONFIG_SYS_NONCACHED_MEMORY:
3204 Size of non-cached memory area. This area of memory will be
3205 typically located right below the malloc() area and mapped
3206 uncached in the MMU. This is useful for drivers that would
3207 otherwise require a lot of explicit cache maintenance. For
3208 some drivers it's also impossible to properly maintain the
3209 cache. For example if the regions that need to be flushed
3210 are not a multiple of the cache-line size, *and* padding
3211 cannot be allocated between the regions to align them (i.e.
3212 if the HW requires a contiguous array of regions, and the
3213 size of each region is not cache-aligned), then a flush of
3214 one region may result in overwriting data that hardware has
3215 written to another region in the same cache-line. This can
3216 happen for example in network drivers where descriptors for
3217 buffers are typically smaller than the CPU cache-line (e.g.
3218 16 bytes vs. 32 or 64 bytes).
3220 Non-cached memory is only supported on 32-bit ARM at present.
3222 - CONFIG_SYS_BOOTM_LEN:
3223 Normally compressed uImages are limited to an
3224 uncompressed size of 8 MBytes. If this is not enough,
3225 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3226 to adjust this setting to your needs.
3228 - CONFIG_SYS_BOOTMAPSZ:
3229 Maximum size of memory mapped by the startup code of
3230 the Linux kernel; all data that must be processed by
3231 the Linux kernel (bd_info, boot arguments, FDT blob if
3232 used) must be put below this limit, unless "bootm_low"
3233 environment variable is defined and non-zero. In such case
3234 all data for the Linux kernel must be between "bootm_low"
3235 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3236 variable "bootm_mapsize" will override the value of
3237 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3238 then the value in "bootm_size" will be used instead.
3240 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3241 Enable initrd_high functionality. If defined then the
3242 initrd_high feature is enabled and the bootm ramdisk subcommand
3245 - CONFIG_SYS_BOOT_GET_CMDLINE:
3246 Enables allocating and saving kernel cmdline in space between
3247 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3249 - CONFIG_SYS_BOOT_GET_KBD:
3250 Enables allocating and saving a kernel copy of the bd_info in
3251 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3253 - CONFIG_SYS_MAX_FLASH_BANKS:
3254 Max number of Flash memory banks
3256 - CONFIG_SYS_MAX_FLASH_SECT:
3257 Max number of sectors on a Flash chip
3259 - CONFIG_SYS_FLASH_ERASE_TOUT:
3260 Timeout for Flash erase operations (in ms)
3262 - CONFIG_SYS_FLASH_WRITE_TOUT:
3263 Timeout for Flash write operations (in ms)
3265 - CONFIG_SYS_FLASH_LOCK_TOUT
3266 Timeout for Flash set sector lock bit operation (in ms)
3268 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3269 Timeout for Flash clear lock bits operation (in ms)
3271 - CONFIG_SYS_FLASH_PROTECTION
3272 If defined, hardware flash sectors protection is used
3273 instead of U-Boot software protection.
3275 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3277 Enable TFTP transfers directly to flash memory;
3278 without this option such a download has to be
3279 performed in two steps: (1) download to RAM, and (2)
3280 copy from RAM to flash.
3282 The two-step approach is usually more reliable, since
3283 you can check if the download worked before you erase
3284 the flash, but in some situations (when system RAM is
3285 too limited to allow for a temporary copy of the
3286 downloaded image) this option may be very useful.
3288 - CONFIG_SYS_FLASH_CFI:
3289 Define if the flash driver uses extra elements in the
3290 common flash structure for storing flash geometry.
3292 - CONFIG_FLASH_CFI_DRIVER
3293 This option also enables the building of the cfi_flash driver
3294 in the drivers directory
3296 - CONFIG_FLASH_CFI_MTD
3297 This option enables the building of the cfi_mtd driver
3298 in the drivers directory. The driver exports CFI flash
3301 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3302 Use buffered writes to flash.
3304 - CONFIG_FLASH_SPANSION_S29WS_N
3305 s29ws-n MirrorBit flash has non-standard addresses for buffered
3308 - CONFIG_SYS_FLASH_QUIET_TEST
3309 If this option is defined, the common CFI flash doesn't
3310 print it's warning upon not recognized FLASH banks. This
3311 is useful, if some of the configured banks are only
3312 optionally available.
3314 - CONFIG_FLASH_SHOW_PROGRESS
3315 If defined (must be an integer), print out countdown
3316 digits and dots. Recommended value: 45 (9..1) for 80
3317 column displays, 15 (3..1) for 40 column displays.
3319 - CONFIG_FLASH_VERIFY
3320 If defined, the content of the flash (destination) is compared
3321 against the source after the write operation. An error message
3322 will be printed when the contents are not identical.
3323 Please note that this option is useless in nearly all cases,
3324 since such flash programming errors usually are detected earlier
3325 while unprotecting/erasing/programming. Please only enable
3326 this option if you really know what you are doing.
3328 - CONFIG_SYS_RX_ETH_BUFFER:
3329 Defines the number of Ethernet receive buffers. On some
3330 Ethernet controllers it is recommended to set this value
3331 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3332 buffers can be full shortly after enabling the interface
3333 on high Ethernet traffic.
3334 Defaults to 4 if not defined.
3336 - CONFIG_ENV_MAX_ENTRIES
3338 Maximum number of entries in the hash table that is used
3339 internally to store the environment settings. The default
3340 setting is supposed to be generous and should work in most
3341 cases. This setting can be used to tune behaviour; see
3342 lib/hashtable.c for details.
3344 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3345 - CONFIG_ENV_FLAGS_LIST_STATIC
3346 Enable validation of the values given to environment variables when
3347 calling env set. Variables can be restricted to only decimal,
3348 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3349 the variables can also be restricted to IP address or MAC address.
3351 The format of the list is:
3352 type_attribute = [s|d|x|b|i|m]
3353 access_attribute = [a|r|o|c]
3354 attributes = type_attribute[access_attribute]
3355 entry = variable_name[:attributes]
3358 The type attributes are:
3359 s - String (default)
3362 b - Boolean ([1yYtT|0nNfF])
3366 The access attributes are:
3372 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3373 Define this to a list (string) to define the ".flags"
3374 environment variable in the default or embedded environment.
3376 - CONFIG_ENV_FLAGS_LIST_STATIC
3377 Define this to a list (string) to define validation that
3378 should be done if an entry is not found in the ".flags"
3379 environment variable. To override a setting in the static
3380 list, simply add an entry for the same variable name to the
3383 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3384 regular expression. This allows multiple variables to define the same
3385 flags without explicitly listing them for each variable.
3387 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3388 If defined, don't allow the -f switch to env set override variable
3392 If stdint.h is available with your toolchain you can define this
3393 option to enable it. You can provide option 'USE_STDINT=1' when
3394 building U-Boot to enable this.
3396 The following definitions that deal with the placement and management
3397 of environment data (variable area); in general, we support the
3398 following configurations:
3400 - CONFIG_BUILD_ENVCRC:
3402 Builds up envcrc with the target environment so that external utils
3403 may easily extract it and embed it in final U-Boot images.
3405 BE CAREFUL! The first access to the environment happens quite early
3406 in U-Boot initialization (when we try to get the setting of for the
3407 console baudrate). You *MUST* have mapped your NVRAM area then, or
3410 Please note that even with NVRAM we still use a copy of the
3411 environment in RAM: we could work on NVRAM directly, but we want to
3412 keep settings there always unmodified except somebody uses "saveenv"
3413 to save the current settings.
3415 BE CAREFUL! For some special cases, the local device can not use
3416 "saveenv" command. For example, the local device will get the
3417 environment stored in a remote NOR flash by SRIO or PCIE link,
3418 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3420 - CONFIG_NAND_ENV_DST
3422 Defines address in RAM to which the nand_spl code should copy the
3423 environment. If redundant environment is used, it will be copied to
3424 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3426 Please note that the environment is read-only until the monitor
3427 has been relocated to RAM and a RAM copy of the environment has been
3428 created; also, when using EEPROM you will have to use getenv_f()
3429 until then to read environment variables.
3431 The environment is protected by a CRC32 checksum. Before the monitor
3432 is relocated into RAM, as a result of a bad CRC you will be working
3433 with the compiled-in default environment - *silently*!!! [This is
3434 necessary, because the first environment variable we need is the
3435 "baudrate" setting for the console - if we have a bad CRC, we don't
3436 have any device yet where we could complain.]
3438 Note: once the monitor has been relocated, then it will complain if
3439 the default environment is used; a new CRC is computed as soon as you
3440 use the "saveenv" command to store a valid environment.
3442 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3443 Echo the inverted Ethernet link state to the fault LED.
3445 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3446 also needs to be defined.
3448 - CONFIG_SYS_FAULT_MII_ADDR:
3449 MII address of the PHY to check for the Ethernet link state.
3451 - CONFIG_NS16550_MIN_FUNCTIONS:
3452 Define this if you desire to only have use of the NS16550_init
3453 and NS16550_putc functions for the serial driver located at
3454 drivers/serial/ns16550.c. This option is useful for saving
3455 space for already greatly restricted images, including but not
3456 limited to NAND_SPL configurations.
3458 - CONFIG_DISPLAY_BOARDINFO
3459 Display information about the board that U-Boot is running on
3460 when U-Boot starts up. The board function checkboard() is called
3463 - CONFIG_DISPLAY_BOARDINFO_LATE
3464 Similar to the previous option, but display this information
3465 later, once stdio is running and output goes to the LCD, if
3468 - CONFIG_BOARD_SIZE_LIMIT:
3469 Maximum size of the U-Boot image. When defined, the
3470 build system checks that the actual size does not
3473 Low Level (hardware related) configuration options:
3474 ---------------------------------------------------
3476 - CONFIG_SYS_CACHELINE_SIZE:
3477 Cache Line Size of the CPU.
3479 - CONFIG_SYS_CCSRBAR_DEFAULT:
3480 Default (power-on reset) physical address of CCSR on Freescale
3483 - CONFIG_SYS_CCSRBAR:
3484 Virtual address of CCSR. On a 32-bit build, this is typically
3485 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3487 - CONFIG_SYS_CCSRBAR_PHYS:
3488 Physical address of CCSR. CCSR can be relocated to a new
3489 physical address, if desired. In this case, this macro should
3490 be set to that address. Otherwise, it should be set to the
3491 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3492 is typically relocated on 36-bit builds. It is recommended
3493 that this macro be defined via the _HIGH and _LOW macros:
3495 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3496 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3498 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3499 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3500 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3501 used in assembly code, so it must not contain typecasts or
3502 integer size suffixes (e.g. "ULL").
3504 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3505 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3506 used in assembly code, so it must not contain typecasts or
3507 integer size suffixes (e.g. "ULL").
3509 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3510 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3511 forced to a value that ensures that CCSR is not relocated.
3513 - Floppy Disk Support:
3514 CONFIG_SYS_FDC_DRIVE_NUMBER
3516 the default drive number (default value 0)
3518 CONFIG_SYS_ISA_IO_STRIDE
3520 defines the spacing between FDC chipset registers
3523 CONFIG_SYS_ISA_IO_OFFSET
3525 defines the offset of register from address. It
3526 depends on which part of the data bus is connected to
3527 the FDC chipset. (default value 0)
3529 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3530 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3533 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3534 fdc_hw_init() is called at the beginning of the FDC
3535 setup. fdc_hw_init() must be provided by the board
3536 source code. It is used to make hardware-dependent
3540 Most IDE controllers were designed to be connected with PCI
3541 interface. Only few of them were designed for AHB interface.
3542 When software is doing ATA command and data transfer to
3543 IDE devices through IDE-AHB controller, some additional
3544 registers accessing to these kind of IDE-AHB controller
3547 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3548 DO NOT CHANGE unless you know exactly what you're
3549 doing! (11-4) [MPC8xx systems only]
3551 - CONFIG_SYS_INIT_RAM_ADDR:
3553 Start address of memory area that can be used for
3554 initial data and stack; please note that this must be
3555 writable memory that is working WITHOUT special
3556 initialization, i. e. you CANNOT use normal RAM which
3557 will become available only after programming the
3558 memory controller and running certain initialization
3561 U-Boot uses the following memory types:
3562 - MPC8xx: IMMR (internal memory of the CPU)
3564 - CONFIG_SYS_GBL_DATA_OFFSET:
3566 Offset of the initial data structure in the memory
3567 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3568 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3569 data is located at the end of the available space
3570 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3571 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3572 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3573 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3576 On the MPC824X (or other systems that use the data
3577 cache for initial memory) the address chosen for
3578 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3579 point to an otherwise UNUSED address space between
3580 the top of RAM and the start of the PCI space.
3582 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3584 - CONFIG_SYS_OR_TIMING_SDRAM:
3587 - CONFIG_SYS_MAMR_PTA:
3588 periodic timer for refresh
3590 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3591 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3592 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3593 CONFIG_SYS_BR1_PRELIM:
3594 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3596 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3597 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3598 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3599 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3601 - CONFIG_PCI_ENUM_ONLY
3602 Only scan through and get the devices on the buses.
3603 Don't do any setup work, presumably because someone or
3604 something has already done it, and we don't need to do it
3605 a second time. Useful for platforms that are pre-booted
3606 by coreboot or similar.
3608 - CONFIG_PCI_INDIRECT_BRIDGE:
3609 Enable support for indirect PCI bridges.
3612 Chip has SRIO or not
3615 Board has SRIO 1 port available
3618 Board has SRIO 2 port available
3620 - CONFIG_SRIO_PCIE_BOOT_MASTER
3621 Board can support master function for Boot from SRIO and PCIE
3623 - CONFIG_SYS_SRIOn_MEM_VIRT:
3624 Virtual Address of SRIO port 'n' memory region
3626 - CONFIG_SYS_SRIOn_MEM_PHYS:
3627 Physical Address of SRIO port 'n' memory region
3629 - CONFIG_SYS_SRIOn_MEM_SIZE:
3630 Size of SRIO port 'n' memory region
3632 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3633 Defined to tell the NAND controller that the NAND chip is using
3635 Not all NAND drivers use this symbol.
3636 Example of drivers that use it:
3637 - drivers/mtd/nand/ndfc.c
3638 - drivers/mtd/nand/mxc_nand.c
3640 - CONFIG_SYS_NDFC_EBC0_CFG
3641 Sets the EBC0_CFG register for the NDFC. If not defined
3642 a default value will be used.
3645 Get DDR timing information from an I2C EEPROM. Common
3646 with pluggable memory modules such as SODIMMs
3649 I2C address of the SPD EEPROM
3651 - CONFIG_SYS_SPD_BUS_NUM
3652 If SPD EEPROM is on an I2C bus other than the first
3653 one, specify here. Note that the value must resolve
3654 to something your driver can deal with.
3656 - CONFIG_SYS_DDR_RAW_TIMING
3657 Get DDR timing information from other than SPD. Common with
3658 soldered DDR chips onboard without SPD. DDR raw timing
3659 parameters are extracted from datasheet and hard-coded into
3660 header files or board specific files.
3662 - CONFIG_FSL_DDR_INTERACTIVE
3663 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3665 - CONFIG_FSL_DDR_SYNC_REFRESH
3666 Enable sync of refresh for multiple controllers.
3668 - CONFIG_FSL_DDR_BIST
3669 Enable built-in memory test for Freescale DDR controllers.
3671 - CONFIG_SYS_83XX_DDR_USES_CS0
3672 Only for 83xx systems. If specified, then DDR should
3673 be configured using CS0 and CS1 instead of CS2 and CS3.
3676 Enable RMII mode for all FECs.
3677 Note that this is a global option, we can't
3678 have one FEC in standard MII mode and another in RMII mode.
3680 - CONFIG_CRC32_VERIFY
3681 Add a verify option to the crc32 command.
3684 => crc32 -v <address> <count> <crc32>
3686 Where address/count indicate a memory area
3687 and crc32 is the correct crc32 which the
3691 Add the "loopw" memory command. This only takes effect if
3692 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3695 Add the "mdc" and "mwc" memory commands. These are cyclic
3700 This command will print 4 bytes (10,11,12,13) each 500 ms.
3702 => mwc.l 100 12345678 10
3703 This command will write 12345678 to address 100 all 10 ms.
3705 This only takes effect if the memory commands are activated
3706 globally (CONFIG_CMD_MEMORY).
3708 - CONFIG_SKIP_LOWLEVEL_INIT
3709 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3710 low level initializations (like setting up the memory
3711 controller) are omitted and/or U-Boot does not
3712 relocate itself into RAM.
3714 Normally this variable MUST NOT be defined. The only
3715 exception is when U-Boot is loaded (to RAM) by some
3716 other boot loader or by a debugger which performs
3717 these initializations itself.
3719 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3720 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3721 to be skipped. The normal CP15 init (such as enabling the
3722 instruction cache) is still performed.
3725 Modifies the behaviour of start.S when compiling a loader
3726 that is executed before the actual U-Boot. E.g. when
3727 compiling a NAND SPL.
3730 Modifies the behaviour of start.S when compiling a loader
3731 that is executed after the SPL and before the actual U-Boot.
3732 It is loaded by the SPL.
3734 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3735 Only for 85xx systems. If this variable is specified, the section
3736 .resetvec is not kept and the section .bootpg is placed in the
3737 previous 4k of the .text section.
3739 - CONFIG_ARCH_MAP_SYSMEM
3740 Generally U-Boot (and in particular the md command) uses
3741 effective address. It is therefore not necessary to regard
3742 U-Boot address as virtual addresses that need to be translated
3743 to physical addresses. However, sandbox requires this, since
3744 it maintains its own little RAM buffer which contains all
3745 addressable memory. This option causes some memory accesses
3746 to be mapped through map_sysmem() / unmap_sysmem().
3748 - CONFIG_X86_RESET_VECTOR
3749 If defined, the x86 reset vector code is included. This is not
3750 needed when U-Boot is running from Coreboot.
3752 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3753 Enables the RTC32K OSC on AM33xx based plattforms
3755 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3756 Option to disable subpage write in NAND driver
3757 driver that uses this:
3758 drivers/mtd/nand/davinci_nand.c
3760 Freescale QE/FMAN Firmware Support:
3761 -----------------------------------
3763 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3764 loading of "firmware", which is encoded in the QE firmware binary format.
3765 This firmware often needs to be loaded during U-Boot booting, so macros
3766 are used to identify the storage device (NOR flash, SPI, etc) and the address
3769 - CONFIG_SYS_FMAN_FW_ADDR
3770 The address in the storage device where the FMAN microcode is located. The
3771 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3774 - CONFIG_SYS_QE_FW_ADDR
3775 The address in the storage device where the QE microcode is located. The
3776 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3779 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3780 The maximum possible size of the firmware. The firmware binary format
3781 has a field that specifies the actual size of the firmware, but it
3782 might not be possible to read any part of the firmware unless some
3783 local storage is allocated to hold the entire firmware first.
3785 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3786 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3787 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3788 virtual address in NOR flash.
3790 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3791 Specifies that QE/FMAN firmware is located in NAND flash.
3792 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3794 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3795 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3796 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3798 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3799 Specifies that QE/FMAN firmware is located in the remote (master)
3800 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3801 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3802 window->master inbound window->master LAW->the ucode address in
3803 master's memory space.
3805 Freescale Layerscape Management Complex Firmware Support:
3806 ---------------------------------------------------------
3807 The Freescale Layerscape Management Complex (MC) supports the loading of
3809 This firmware often needs to be loaded during U-Boot booting, so macros
3810 are used to identify the storage device (NOR flash, SPI, etc) and the address
3813 - CONFIG_FSL_MC_ENET
3814 Enable the MC driver for Layerscape SoCs.
3816 Freescale Layerscape Debug Server Support:
3817 -------------------------------------------
3818 The Freescale Layerscape Debug Server Support supports the loading of
3819 "Debug Server firmware" and triggering SP boot-rom.
3820 This firmware often needs to be loaded during U-Boot booting.
3822 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3823 Define alignment of reserved memory MC requires
3828 In order to achieve reproducible builds, timestamps used in the U-Boot build
3829 process have to be set to a fixed value.
3831 This is done using the SOURCE_DATE_EPOCH environment variable.
3832 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3833 option for U-Boot or an environment variable in U-Boot.
3835 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3837 Building the Software:
3838 ======================
3840 Building U-Boot has been tested in several native build environments
3841 and in many different cross environments. Of course we cannot support
3842 all possibly existing versions of cross development tools in all
3843 (potentially obsolete) versions. In case of tool chain problems we
3844 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3845 which is extensively used to build and test U-Boot.
3847 If you are not using a native environment, it is assumed that you
3848 have GNU cross compiling tools available in your path. In this case,
3849 you must set the environment variable CROSS_COMPILE in your shell.
3850 Note that no changes to the Makefile or any other source files are
3851 necessary. For example using the ELDK on a 4xx CPU, please enter:
3853 $ CROSS_COMPILE=ppc_4xx-
3854 $ export CROSS_COMPILE
3856 Note: If you wish to generate Windows versions of the utilities in
3857 the tools directory you can use the MinGW toolchain
3858 (http://www.mingw.org). Set your HOST tools to the MinGW
3859 toolchain and execute 'make tools'. For example:
3861 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3863 Binaries such as tools/mkimage.exe will be created which can
3864 be executed on computers running Windows.
3866 U-Boot is intended to be simple to build. After installing the
3867 sources you must configure U-Boot for one specific board type. This
3872 where "NAME_defconfig" is the name of one of the existing configu-
3873 rations; see boards.cfg for supported names.
3875 Note: for some board special configuration names may exist; check if
3876 additional information is available from the board vendor; for
3877 instance, the TQM823L systems are available without (standard)
3878 or with LCD support. You can select such additional "features"
3879 when choosing the configuration, i. e.
3881 make TQM823L_defconfig
3882 - will configure for a plain TQM823L, i. e. no LCD support
3884 make TQM823L_LCD_defconfig
3885 - will configure for a TQM823L with U-Boot console on LCD
3890 Finally, type "make all", and you should get some working U-Boot
3891 images ready for download to / installation on your system:
3893 - "u-boot.bin" is a raw binary image
3894 - "u-boot" is an image in ELF binary format
3895 - "u-boot.srec" is in Motorola S-Record format
3897 By default the build is performed locally and the objects are saved
3898 in the source directory. One of the two methods can be used to change
3899 this behavior and build U-Boot to some external directory:
3901 1. Add O= to the make command line invocations:
3903 make O=/tmp/build distclean
3904 make O=/tmp/build NAME_defconfig
3905 make O=/tmp/build all
3907 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3909 export KBUILD_OUTPUT=/tmp/build
3914 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3918 Please be aware that the Makefiles assume you are using GNU make, so
3919 for instance on NetBSD you might need to use "gmake" instead of
3923 If the system board that you have is not listed, then you will need
3924 to port U-Boot to your hardware platform. To do this, follow these
3927 1. Create a new directory to hold your board specific code. Add any
3928 files you need. In your board directory, you will need at least
3929 the "Makefile" and a "<board>.c".
3930 2. Create a new configuration file "include/configs/<board>.h" for
3932 3. If you're porting U-Boot to a new CPU, then also create a new
3933 directory to hold your CPU specific code. Add any files you need.
3934 4. Run "make <board>_defconfig" with your new name.
3935 5. Type "make", and you should get a working "u-boot.srec" file
3936 to be installed on your target system.
3937 6. Debug and solve any problems that might arise.
3938 [Of course, this last step is much harder than it sounds.]
3941 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3942 ==============================================================
3944 If you have modified U-Boot sources (for instance added a new board
3945 or support for new devices, a new CPU, etc.) you are expected to
3946 provide feedback to the other developers. The feedback normally takes
3947 the form of a "patch", i. e. a context diff against a certain (latest
3948 official or latest in the git repository) version of U-Boot sources.
3950 But before you submit such a patch, please verify that your modifi-
3951 cation did not break existing code. At least make sure that *ALL* of
3952 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3953 just run the buildman script (tools/buildman/buildman), which will
3954 configure and build U-Boot for ALL supported system. Be warned, this
3955 will take a while. Please see the buildman README, or run 'buildman -H'
3959 See also "U-Boot Porting Guide" below.
3962 Monitor Commands - Overview:
3963 ============================
3965 go - start application at address 'addr'
3966 run - run commands in an environment variable
3967 bootm - boot application image from memory
3968 bootp - boot image via network using BootP/TFTP protocol
3969 bootz - boot zImage from memory
3970 tftpboot- boot image via network using TFTP protocol
3971 and env variables "ipaddr" and "serverip"
3972 (and eventually "gatewayip")
3973 tftpput - upload a file via network using TFTP protocol
3974 rarpboot- boot image via network using RARP/TFTP protocol
3975 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3976 loads - load S-Record file over serial line
3977 loadb - load binary file over serial line (kermit mode)
3979 mm - memory modify (auto-incrementing)
3980 nm - memory modify (constant address)
3981 mw - memory write (fill)
3983 cmp - memory compare
3984 crc32 - checksum calculation
3985 i2c - I2C sub-system
3986 sspi - SPI utility commands
3987 base - print or set address offset
3988 printenv- print environment variables
3989 setenv - set environment variables
3990 saveenv - save environment variables to persistent storage
3991 protect - enable or disable FLASH write protection
3992 erase - erase FLASH memory
3993 flinfo - print FLASH memory information
3994 nand - NAND memory operations (see doc/README.nand)
3995 bdinfo - print Board Info structure
3996 iminfo - print header information for application image
3997 coninfo - print console devices and informations
3998 ide - IDE sub-system
3999 loop - infinite loop on address range
4000 loopw - infinite write loop on address range
4001 mtest - simple RAM test
4002 icache - enable or disable instruction cache
4003 dcache - enable or disable data cache
4004 reset - Perform RESET of the CPU
4005 echo - echo args to console
4006 version - print monitor version
4007 help - print online help
4008 ? - alias for 'help'
4011 Monitor Commands - Detailed Description:
4012 ========================================
4016 For now: just type "help <command>".
4019 Environment Variables:
4020 ======================
4022 U-Boot supports user configuration using Environment Variables which
4023 can be made persistent by saving to Flash memory.
4025 Environment Variables are set using "setenv", printed using
4026 "printenv", and saved to Flash using "saveenv". Using "setenv"
4027 without a value can be used to delete a variable from the
4028 environment. As long as you don't save the environment you are
4029 working with an in-memory copy. In case the Flash area containing the
4030 environment is erased by accident, a default environment is provided.
4032 Some configuration options can be set using Environment Variables.
4034 List of environment variables (most likely not complete):
4036 baudrate - see CONFIG_BAUDRATE
4038 bootdelay - see CONFIG_BOOTDELAY
4040 bootcmd - see CONFIG_BOOTCOMMAND
4042 bootargs - Boot arguments when booting an RTOS image
4044 bootfile - Name of the image to load with TFTP
4046 bootm_low - Memory range available for image processing in the bootm
4047 command can be restricted. This variable is given as
4048 a hexadecimal number and defines lowest address allowed
4049 for use by the bootm command. See also "bootm_size"
4050 environment variable. Address defined by "bootm_low" is
4051 also the base of the initial memory mapping for the Linux
4052 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4055 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4056 This variable is given as a hexadecimal number and it
4057 defines the size of the memory region starting at base
4058 address bootm_low that is accessible by the Linux kernel
4059 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4060 as the default value if it is defined, and bootm_size is
4063 bootm_size - Memory range available for image processing in the bootm
4064 command can be restricted. This variable is given as
4065 a hexadecimal number and defines the size of the region
4066 allowed for use by the bootm command. See also "bootm_low"
4067 environment variable.
4069 updatefile - Location of the software update file on a TFTP server, used
4070 by the automatic software update feature. Please refer to
4071 documentation in doc/README.update for more details.
4073 autoload - if set to "no" (any string beginning with 'n'),
4074 "bootp" will just load perform a lookup of the
4075 configuration from the BOOTP server, but not try to
4076 load any image using TFTP
4078 autostart - if set to "yes", an image loaded using the "bootp",
4079 "rarpboot", "tftpboot" or "diskboot" commands will
4080 be automatically started (by internally calling
4083 If set to "no", a standalone image passed to the
4084 "bootm" command will be copied to the load address
4085 (and eventually uncompressed), but NOT be started.
4086 This can be used to load and uncompress arbitrary
4089 fdt_high - if set this restricts the maximum address that the
4090 flattened device tree will be copied into upon boot.
4091 For example, if you have a system with 1 GB memory
4092 at physical address 0x10000000, while Linux kernel
4093 only recognizes the first 704 MB as low memory, you
4094 may need to set fdt_high as 0x3C000000 to have the
4095 device tree blob be copied to the maximum address
4096 of the 704 MB low memory, so that Linux kernel can
4097 access it during the boot procedure.
4099 If this is set to the special value 0xFFFFFFFF then
4100 the fdt will not be copied at all on boot. For this
4101 to work it must reside in writable memory, have
4102 sufficient padding on the end of it for u-boot to
4103 add the information it needs into it, and the memory
4104 must be accessible by the kernel.
4106 fdtcontroladdr- if set this is the address of the control flattened
4107 device tree used by U-Boot when CONFIG_OF_CONTROL is
4110 i2cfast - (PPC405GP|PPC405EP only)
4111 if set to 'y' configures Linux I2C driver for fast
4112 mode (400kHZ). This environment variable is used in
4113 initialization code. So, for changes to be effective
4114 it must be saved and board must be reset.
4116 initrd_high - restrict positioning of initrd images:
4117 If this variable is not set, initrd images will be
4118 copied to the highest possible address in RAM; this
4119 is usually what you want since it allows for
4120 maximum initrd size. If for some reason you want to
4121 make sure that the initrd image is loaded below the
4122 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4123 variable to a value of "no" or "off" or "0".
4124 Alternatively, you can set it to a maximum upper
4125 address to use (U-Boot will still check that it
4126 does not overwrite the U-Boot stack and data).
4128 For instance, when you have a system with 16 MB
4129 RAM, and want to reserve 4 MB from use by Linux,
4130 you can do this by adding "mem=12M" to the value of
4131 the "bootargs" variable. However, now you must make
4132 sure that the initrd image is placed in the first
4133 12 MB as well - this can be done with
4135 setenv initrd_high 00c00000
4137 If you set initrd_high to 0xFFFFFFFF, this is an
4138 indication to U-Boot that all addresses are legal
4139 for the Linux kernel, including addresses in flash
4140 memory. In this case U-Boot will NOT COPY the
4141 ramdisk at all. This may be useful to reduce the
4142 boot time on your system, but requires that this
4143 feature is supported by your Linux kernel.
4145 ipaddr - IP address; needed for tftpboot command
4147 loadaddr - Default load address for commands like "bootp",
4148 "rarpboot", "tftpboot", "loadb" or "diskboot"
4150 loads_echo - see CONFIG_LOADS_ECHO
4152 serverip - TFTP server IP address; needed for tftpboot command
4154 bootretry - see CONFIG_BOOT_RETRY_TIME
4156 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4158 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4160 ethprime - controls which interface is used first.
4162 ethact - controls which interface is currently active.
4163 For example you can do the following
4165 => setenv ethact FEC
4166 => ping 192.168.0.1 # traffic sent on FEC
4167 => setenv ethact SCC
4168 => ping 10.0.0.1 # traffic sent on SCC
4170 ethrotate - When set to "no" U-Boot does not go through all
4171 available network interfaces.
4172 It just stays at the currently selected interface.
4174 netretry - When set to "no" each network operation will
4175 either succeed or fail without retrying.
4176 When set to "once" the network operation will
4177 fail when all the available network interfaces
4178 are tried once without success.
4179 Useful on scripts which control the retry operation
4182 npe_ucode - set load address for the NPE microcode
4184 silent_linux - If set then Linux will be told to boot silently, by
4185 changing the console to be empty. If "yes" it will be
4186 made silent. If "no" it will not be made silent. If
4187 unset, then it will be made silent if the U-Boot console
4190 tftpsrcp - If this is set, the value is used for TFTP's
4193 tftpdstp - If this is set, the value is used for TFTP's UDP
4194 destination port instead of the Well Know Port 69.
4196 tftpblocksize - Block size to use for TFTP transfers; if not set,
4197 we use the TFTP server's default block size
4199 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4200 seconds, minimum value is 1000 = 1 second). Defines
4201 when a packet is considered to be lost so it has to
4202 be retransmitted. The default is 5000 = 5 seconds.
4203 Lowering this value may make downloads succeed
4204 faster in networks with high packet loss rates or
4205 with unreliable TFTP servers.
4207 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4208 unit, minimum value = 0). Defines how many timeouts
4209 can happen during a single file transfer before that
4210 transfer is aborted. The default is 10, and 0 means
4211 'no timeouts allowed'. Increasing this value may help
4212 downloads succeed with high packet loss rates, or with
4213 unreliable TFTP servers or client hardware.
4215 vlan - When set to a value < 4095 the traffic over
4216 Ethernet is encapsulated/received over 802.1q
4219 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4220 Unsigned value, in milliseconds. If not set, the period will
4221 be either the default (28000), or a value based on
4222 CONFIG_NET_RETRY_COUNT, if defined. This value has
4223 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4225 The following image location variables contain the location of images
4226 used in booting. The "Image" column gives the role of the image and is
4227 not an environment variable name. The other columns are environment
4228 variable names. "File Name" gives the name of the file on a TFTP
4229 server, "RAM Address" gives the location in RAM the image will be
4230 loaded to, and "Flash Location" gives the image's address in NOR
4231 flash or offset in NAND flash.
4233 *Note* - these variables don't have to be defined for all boards, some
4234 boards currently use other variables for these purposes, and some
4235 boards use these variables for other purposes.
4237 Image File Name RAM Address Flash Location
4238 ----- --------- ----------- --------------
4239 u-boot u-boot u-boot_addr_r u-boot_addr
4240 Linux kernel bootfile kernel_addr_r kernel_addr
4241 device tree blob fdtfile fdt_addr_r fdt_addr
4242 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4244 The following environment variables may be used and automatically
4245 updated by the network boot commands ("bootp" and "rarpboot"),
4246 depending the information provided by your boot server:
4248 bootfile - see above
4249 dnsip - IP address of your Domain Name Server
4250 dnsip2 - IP address of your secondary Domain Name Server
4251 gatewayip - IP address of the Gateway (Router) to use
4252 hostname - Target hostname
4254 netmask - Subnet Mask
4255 rootpath - Pathname of the root filesystem on the NFS server
4256 serverip - see above
4259 There are two special Environment Variables:
4261 serial# - contains hardware identification information such
4262 as type string and/or serial number
4263 ethaddr - Ethernet address
4265 These variables can be set only once (usually during manufacturing of
4266 the board). U-Boot refuses to delete or overwrite these variables
4267 once they have been set once.
4270 Further special Environment Variables:
4272 ver - Contains the U-Boot version string as printed
4273 with the "version" command. This variable is
4274 readonly (see CONFIG_VERSION_VARIABLE).
4277 Please note that changes to some configuration parameters may take
4278 only effect after the next boot (yes, that's just like Windoze :-).
4281 Callback functions for environment variables:
4282 ---------------------------------------------
4284 For some environment variables, the behavior of u-boot needs to change
4285 when their values are changed. This functionality allows functions to
4286 be associated with arbitrary variables. On creation, overwrite, or
4287 deletion, the callback will provide the opportunity for some side
4288 effect to happen or for the change to be rejected.
4290 The callbacks are named and associated with a function using the
4291 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4293 These callbacks are associated with variables in one of two ways. The
4294 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4295 in the board configuration to a string that defines a list of
4296 associations. The list must be in the following format:
4298 entry = variable_name[:callback_name]
4301 If the callback name is not specified, then the callback is deleted.
4302 Spaces are also allowed anywhere in the list.
4304 Callbacks can also be associated by defining the ".callbacks" variable
4305 with the same list format above. Any association in ".callbacks" will
4306 override any association in the static list. You can define
4307 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4308 ".callbacks" environment variable in the default or embedded environment.
4310 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4311 regular expression. This allows multiple variables to be connected to
4312 the same callback without explicitly listing them all out.
4315 Command Line Parsing:
4316 =====================
4318 There are two different command line parsers available with U-Boot:
4319 the old "simple" one, and the much more powerful "hush" shell:
4321 Old, simple command line parser:
4322 --------------------------------
4324 - supports environment variables (through setenv / saveenv commands)
4325 - several commands on one line, separated by ';'
4326 - variable substitution using "... ${name} ..." syntax
4327 - special characters ('$', ';') can be escaped by prefixing with '\',
4329 setenv bootcmd bootm \${address}
4330 - You can also escape text by enclosing in single apostrophes, for example:
4331 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4336 - similar to Bourne shell, with control structures like
4337 if...then...else...fi, for...do...done; while...do...done,
4338 until...do...done, ...
4339 - supports environment ("global") variables (through setenv / saveenv
4340 commands) and local shell variables (through standard shell syntax
4341 "name=value"); only environment variables can be used with "run"
4347 (1) If a command line (or an environment variable executed by a "run"
4348 command) contains several commands separated by semicolon, and
4349 one of these commands fails, then the remaining commands will be
4352 (2) If you execute several variables with one call to run (i. e.
4353 calling run with a list of variables as arguments), any failing
4354 command will cause "run" to terminate, i. e. the remaining
4355 variables are not executed.
4357 Note for Redundant Ethernet Interfaces:
4358 =======================================
4360 Some boards come with redundant Ethernet interfaces; U-Boot supports
4361 such configurations and is capable of automatic selection of a
4362 "working" interface when needed. MAC assignment works as follows:
4364 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4365 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4366 "eth1addr" (=>eth1), "eth2addr", ...
4368 If the network interface stores some valid MAC address (for instance
4369 in SROM), this is used as default address if there is NO correspon-
4370 ding setting in the environment; if the corresponding environment
4371 variable is set, this overrides the settings in the card; that means:
4373 o If the SROM has a valid MAC address, and there is no address in the
4374 environment, the SROM's address is used.
4376 o If there is no valid address in the SROM, and a definition in the
4377 environment exists, then the value from the environment variable is
4380 o If both the SROM and the environment contain a MAC address, and
4381 both addresses are the same, this MAC address is used.
4383 o If both the SROM and the environment contain a MAC address, and the
4384 addresses differ, the value from the environment is used and a
4387 o If neither SROM nor the environment contain a MAC address, an error
4388 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4389 a random, locally-assigned MAC is used.
4391 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4392 will be programmed into hardware as part of the initialization process. This
4393 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4394 The naming convention is as follows:
4395 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4400 U-Boot is capable of booting (and performing other auxiliary operations on)
4401 images in two formats:
4403 New uImage format (FIT)
4404 -----------------------
4406 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4407 to Flattened Device Tree). It allows the use of images with multiple
4408 components (several kernels, ramdisks, etc.), with contents protected by
4409 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4415 Old image format is based on binary files which can be basically anything,
4416 preceded by a special header; see the definitions in include/image.h for
4417 details; basically, the header defines the following image properties:
4419 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4420 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4421 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4422 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4424 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4425 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4426 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4427 * Compression Type (uncompressed, gzip, bzip2)
4433 The header is marked by a special Magic Number, and both the header
4434 and the data portions of the image are secured against corruption by
4441 Although U-Boot should support any OS or standalone application
4442 easily, the main focus has always been on Linux during the design of
4445 U-Boot includes many features that so far have been part of some
4446 special "boot loader" code within the Linux kernel. Also, any
4447 "initrd" images to be used are no longer part of one big Linux image;
4448 instead, kernel and "initrd" are separate images. This implementation
4449 serves several purposes:
4451 - the same features can be used for other OS or standalone
4452 applications (for instance: using compressed images to reduce the
4453 Flash memory footprint)
4455 - it becomes much easier to port new Linux kernel versions because
4456 lots of low-level, hardware dependent stuff are done by U-Boot
4458 - the same Linux kernel image can now be used with different "initrd"
4459 images; of course this also means that different kernel images can
4460 be run with the same "initrd". This makes testing easier (you don't
4461 have to build a new "zImage.initrd" Linux image when you just
4462 change a file in your "initrd"). Also, a field-upgrade of the
4463 software is easier now.
4469 Porting Linux to U-Boot based systems:
4470 ---------------------------------------
4472 U-Boot cannot save you from doing all the necessary modifications to
4473 configure the Linux device drivers for use with your target hardware
4474 (no, we don't intend to provide a full virtual machine interface to
4477 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4479 Just make sure your machine specific header file (for instance
4480 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4481 Information structure as we define in include/asm-<arch>/u-boot.h,
4482 and make sure that your definition of IMAP_ADDR uses the same value
4483 as your U-Boot configuration in CONFIG_SYS_IMMR.
4485 Note that U-Boot now has a driver model, a unified model for drivers.
4486 If you are adding a new driver, plumb it into driver model. If there
4487 is no uclass available, you are encouraged to create one. See
4491 Configuring the Linux kernel:
4492 -----------------------------
4494 No specific requirements for U-Boot. Make sure you have some root
4495 device (initial ramdisk, NFS) for your target system.
4498 Building a Linux Image:
4499 -----------------------
4501 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4502 not used. If you use recent kernel source, a new build target
4503 "uImage" will exist which automatically builds an image usable by
4504 U-Boot. Most older kernels also have support for a "pImage" target,
4505 which was introduced for our predecessor project PPCBoot and uses a
4506 100% compatible format.
4510 make TQM850L_defconfig
4515 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4516 encapsulate a compressed Linux kernel image with header information,
4517 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4519 * build a standard "vmlinux" kernel image (in ELF binary format):
4521 * convert the kernel into a raw binary image:
4523 ${CROSS_COMPILE}-objcopy -O binary \
4524 -R .note -R .comment \
4525 -S vmlinux linux.bin
4527 * compress the binary image:
4531 * package compressed binary image for U-Boot:
4533 mkimage -A ppc -O linux -T kernel -C gzip \
4534 -a 0 -e 0 -n "Linux Kernel Image" \
4535 -d linux.bin.gz uImage
4538 The "mkimage" tool can also be used to create ramdisk images for use
4539 with U-Boot, either separated from the Linux kernel image, or
4540 combined into one file. "mkimage" encapsulates the images with a 64
4541 byte header containing information about target architecture,
4542 operating system, image type, compression method, entry points, time
4543 stamp, CRC32 checksums, etc.
4545 "mkimage" can be called in two ways: to verify existing images and
4546 print the header information, or to build new images.
4548 In the first form (with "-l" option) mkimage lists the information
4549 contained in the header of an existing U-Boot image; this includes
4550 checksum verification:
4552 tools/mkimage -l image
4553 -l ==> list image header information
4555 The second form (with "-d" option) is used to build a U-Boot image
4556 from a "data file" which is used as image payload:
4558 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4559 -n name -d data_file image
4560 -A ==> set architecture to 'arch'
4561 -O ==> set operating system to 'os'
4562 -T ==> set image type to 'type'
4563 -C ==> set compression type 'comp'
4564 -a ==> set load address to 'addr' (hex)
4565 -e ==> set entry point to 'ep' (hex)
4566 -n ==> set image name to 'name'
4567 -d ==> use image data from 'datafile'
4569 Right now, all Linux kernels for PowerPC systems use the same load
4570 address (0x00000000), but the entry point address depends on the
4573 - 2.2.x kernels have the entry point at 0x0000000C,
4574 - 2.3.x and later kernels have the entry point at 0x00000000.
4576 So a typical call to build a U-Boot image would read:
4578 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4579 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4580 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4581 > examples/uImage.TQM850L
4582 Image Name: 2.4.4 kernel for TQM850L
4583 Created: Wed Jul 19 02:34:59 2000
4584 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4585 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4586 Load Address: 0x00000000
4587 Entry Point: 0x00000000
4589 To verify the contents of the image (or check for corruption):
4591 -> tools/mkimage -l examples/uImage.TQM850L
4592 Image Name: 2.4.4 kernel for TQM850L
4593 Created: Wed Jul 19 02:34:59 2000
4594 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4595 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4596 Load Address: 0x00000000
4597 Entry Point: 0x00000000
4599 NOTE: for embedded systems where boot time is critical you can trade
4600 speed for memory and install an UNCOMPRESSED image instead: this
4601 needs more space in Flash, but boots much faster since it does not
4602 need to be uncompressed:
4604 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4605 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4606 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4607 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4608 > examples/uImage.TQM850L-uncompressed
4609 Image Name: 2.4.4 kernel for TQM850L
4610 Created: Wed Jul 19 02:34:59 2000
4611 Image Type: PowerPC Linux Kernel Image (uncompressed)
4612 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4613 Load Address: 0x00000000
4614 Entry Point: 0x00000000
4617 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4618 when your kernel is intended to use an initial ramdisk:
4620 -> tools/mkimage -n 'Simple Ramdisk Image' \
4621 > -A ppc -O linux -T ramdisk -C gzip \
4622 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4623 Image Name: Simple Ramdisk Image
4624 Created: Wed Jan 12 14:01:50 2000
4625 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4626 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4627 Load Address: 0x00000000
4628 Entry Point: 0x00000000
4630 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4631 option performs the converse operation of the mkimage's second form (the "-d"
4632 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4635 tools/dumpimage -i image -T type -p position data_file
4636 -i ==> extract from the 'image' a specific 'data_file'
4637 -T ==> set image type to 'type'
4638 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4641 Installing a Linux Image:
4642 -------------------------
4644 To downloading a U-Boot image over the serial (console) interface,
4645 you must convert the image to S-Record format:
4647 objcopy -I binary -O srec examples/image examples/image.srec
4649 The 'objcopy' does not understand the information in the U-Boot
4650 image header, so the resulting S-Record file will be relative to
4651 address 0x00000000. To load it to a given address, you need to
4652 specify the target address as 'offset' parameter with the 'loads'
4655 Example: install the image to address 0x40100000 (which on the
4656 TQM8xxL is in the first Flash bank):
4658 => erase 40100000 401FFFFF
4664 ## Ready for S-Record download ...
4665 ~>examples/image.srec
4666 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4668 15989 15990 15991 15992
4669 [file transfer complete]
4671 ## Start Addr = 0x00000000
4674 You can check the success of the download using the 'iminfo' command;
4675 this includes a checksum verification so you can be sure no data
4676 corruption happened:
4680 ## Checking Image at 40100000 ...
4681 Image Name: 2.2.13 for initrd on TQM850L
4682 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4683 Data Size: 335725 Bytes = 327 kB = 0 MB
4684 Load Address: 00000000
4685 Entry Point: 0000000c
4686 Verifying Checksum ... OK
4692 The "bootm" command is used to boot an application that is stored in
4693 memory (RAM or Flash). In case of a Linux kernel image, the contents
4694 of the "bootargs" environment variable is passed to the kernel as
4695 parameters. You can check and modify this variable using the
4696 "printenv" and "setenv" commands:
4699 => printenv bootargs
4700 bootargs=root=/dev/ram
4702 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4704 => printenv bootargs
4705 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4708 ## Booting Linux kernel at 40020000 ...
4709 Image Name: 2.2.13 for NFS on TQM850L
4710 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4711 Data Size: 381681 Bytes = 372 kB = 0 MB
4712 Load Address: 00000000
4713 Entry Point: 0000000c
4714 Verifying Checksum ... OK
4715 Uncompressing Kernel Image ... OK
4716 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
4717 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4718 time_init: decrementer frequency = 187500000/60
4719 Calibrating delay loop... 49.77 BogoMIPS
4720 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4723 If you want to boot a Linux kernel with initial RAM disk, you pass
4724 the memory addresses of both the kernel and the initrd image (PPBCOOT
4725 format!) to the "bootm" command:
4727 => imi 40100000 40200000
4729 ## Checking Image at 40100000 ...
4730 Image Name: 2.2.13 for initrd on TQM850L
4731 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4732 Data Size: 335725 Bytes = 327 kB = 0 MB
4733 Load Address: 00000000
4734 Entry Point: 0000000c
4735 Verifying Checksum ... OK
4737 ## Checking Image at 40200000 ...
4738 Image Name: Simple Ramdisk Image
4739 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4740 Data Size: 566530 Bytes = 553 kB = 0 MB
4741 Load Address: 00000000
4742 Entry Point: 00000000
4743 Verifying Checksum ... OK
4745 => bootm 40100000 40200000
4746 ## Booting Linux kernel at 40100000 ...
4747 Image Name: 2.2.13 for initrd on TQM850L
4748 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4749 Data Size: 335725 Bytes = 327 kB = 0 MB
4750 Load Address: 00000000
4751 Entry Point: 0000000c
4752 Verifying Checksum ... OK
4753 Uncompressing Kernel Image ... OK
4754 ## Loading RAMDisk Image at 40200000 ...
4755 Image Name: Simple Ramdisk Image
4756 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4757 Data Size: 566530 Bytes = 553 kB = 0 MB
4758 Load Address: 00000000
4759 Entry Point: 00000000
4760 Verifying Checksum ... OK
4761 Loading Ramdisk ... OK
4762 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
4763 Boot arguments: root=/dev/ram
4764 time_init: decrementer frequency = 187500000/60
4765 Calibrating delay loop... 49.77 BogoMIPS
4767 RAMDISK: Compressed image found at block 0
4768 VFS: Mounted root (ext2 filesystem).
4772 Boot Linux and pass a flat device tree:
4775 First, U-Boot must be compiled with the appropriate defines. See the section
4776 titled "Linux Kernel Interface" above for a more in depth explanation. The
4777 following is an example of how to start a kernel and pass an updated
4783 oft=oftrees/mpc8540ads.dtb
4784 => tftp $oftaddr $oft
4785 Speed: 1000, full duplex
4787 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4788 Filename 'oftrees/mpc8540ads.dtb'.
4789 Load address: 0x300000
4792 Bytes transferred = 4106 (100a hex)
4793 => tftp $loadaddr $bootfile
4794 Speed: 1000, full duplex
4796 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4798 Load address: 0x200000
4799 Loading:############
4801 Bytes transferred = 1029407 (fb51f hex)
4806 => bootm $loadaddr - $oftaddr
4807 ## Booting image at 00200000 ...
4808 Image Name: Linux-2.6.17-dirty
4809 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4810 Data Size: 1029343 Bytes = 1005.2 kB
4811 Load Address: 00000000
4812 Entry Point: 00000000
4813 Verifying Checksum ... OK
4814 Uncompressing Kernel Image ... OK
4815 Booting using flat device tree at 0x300000
4816 Using MPC85xx ADS machine description
4817 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4821 More About U-Boot Image Types:
4822 ------------------------------
4824 U-Boot supports the following image types:
4826 "Standalone Programs" are directly runnable in the environment
4827 provided by U-Boot; it is expected that (if they behave
4828 well) you can continue to work in U-Boot after return from
4829 the Standalone Program.
4830 "OS Kernel Images" are usually images of some Embedded OS which
4831 will take over control completely. Usually these programs
4832 will install their own set of exception handlers, device
4833 drivers, set up the MMU, etc. - this means, that you cannot
4834 expect to re-enter U-Boot except by resetting the CPU.
4835 "RAMDisk Images" are more or less just data blocks, and their
4836 parameters (address, size) are passed to an OS kernel that is
4838 "Multi-File Images" contain several images, typically an OS
4839 (Linux) kernel image and one or more data images like
4840 RAMDisks. This construct is useful for instance when you want
4841 to boot over the network using BOOTP etc., where the boot
4842 server provides just a single image file, but you want to get
4843 for instance an OS kernel and a RAMDisk image.
4845 "Multi-File Images" start with a list of image sizes, each
4846 image size (in bytes) specified by an "uint32_t" in network
4847 byte order. This list is terminated by an "(uint32_t)0".
4848 Immediately after the terminating 0 follow the images, one by
4849 one, all aligned on "uint32_t" boundaries (size rounded up to
4850 a multiple of 4 bytes).
4852 "Firmware Images" are binary images containing firmware (like
4853 U-Boot or FPGA images) which usually will be programmed to
4856 "Script files" are command sequences that will be executed by
4857 U-Boot's command interpreter; this feature is especially
4858 useful when you configure U-Boot to use a real shell (hush)
4859 as command interpreter.
4861 Booting the Linux zImage:
4862 -------------------------
4864 On some platforms, it's possible to boot Linux zImage. This is done
4865 using the "bootz" command. The syntax of "bootz" command is the same
4866 as the syntax of "bootm" command.
4868 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4869 kernel with raw initrd images. The syntax is slightly different, the
4870 address of the initrd must be augmented by it's size, in the following
4871 format: "<initrd addres>:<initrd size>".
4877 One of the features of U-Boot is that you can dynamically load and
4878 run "standalone" applications, which can use some resources of
4879 U-Boot like console I/O functions or interrupt services.
4881 Two simple examples are included with the sources:
4886 'examples/hello_world.c' contains a small "Hello World" Demo
4887 application; it is automatically compiled when you build U-Boot.
4888 It's configured to run at address 0x00040004, so you can play with it
4892 ## Ready for S-Record download ...
4893 ~>examples/hello_world.srec
4894 1 2 3 4 5 6 7 8 9 10 11 ...
4895 [file transfer complete]
4897 ## Start Addr = 0x00040004
4899 => go 40004 Hello World! This is a test.
4900 ## Starting application at 0x00040004 ...
4911 Hit any key to exit ...
4913 ## Application terminated, rc = 0x0
4915 Another example, which demonstrates how to register a CPM interrupt
4916 handler with the U-Boot code, can be found in 'examples/timer.c'.
4917 Here, a CPM timer is set up to generate an interrupt every second.
4918 The interrupt service routine is trivial, just printing a '.'
4919 character, but this is just a demo program. The application can be
4920 controlled by the following keys:
4922 ? - print current values og the CPM Timer registers
4923 b - enable interrupts and start timer
4924 e - stop timer and disable interrupts
4925 q - quit application
4928 ## Ready for S-Record download ...
4929 ~>examples/timer.srec
4930 1 2 3 4 5 6 7 8 9 10 11 ...
4931 [file transfer complete]
4933 ## Start Addr = 0x00040004
4936 ## Starting application at 0x00040004 ...
4939 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4942 [q, b, e, ?] Set interval 1000000 us
4945 [q, b, e, ?] ........
4946 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4949 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4952 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4955 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4957 [q, b, e, ?] ...Stopping timer
4959 [q, b, e, ?] ## Application terminated, rc = 0x0
4965 Over time, many people have reported problems when trying to use the
4966 "minicom" terminal emulation program for serial download. I (wd)
4967 consider minicom to be broken, and recommend not to use it. Under
4968 Unix, I recommend to use C-Kermit for general purpose use (and
4969 especially for kermit binary protocol download ("loadb" command), and
4970 use "cu" for S-Record download ("loads" command). See
4971 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4972 for help with kermit.
4975 Nevertheless, if you absolutely want to use it try adding this
4976 configuration to your "File transfer protocols" section:
4978 Name Program Name U/D FullScr IO-Red. Multi
4979 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4980 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4986 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4987 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4989 Building requires a cross environment; it is known to work on
4990 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4991 need gmake since the Makefiles are not compatible with BSD make).
4992 Note that the cross-powerpc package does not install include files;
4993 attempting to build U-Boot will fail because <machine/ansi.h> is
4994 missing. This file has to be installed and patched manually:
4996 # cd /usr/pkg/cross/powerpc-netbsd/include
4998 # ln -s powerpc machine
4999 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5000 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5002 Native builds *don't* work due to incompatibilities between native
5003 and U-Boot include files.
5005 Booting assumes that (the first part of) the image booted is a
5006 stage-2 loader which in turn loads and then invokes the kernel
5007 proper. Loader sources will eventually appear in the NetBSD source
5008 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5009 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5012 Implementation Internals:
5013 =========================
5015 The following is not intended to be a complete description of every
5016 implementation detail. However, it should help to understand the
5017 inner workings of U-Boot and make it easier to port it to custom
5021 Initial Stack, Global Data:
5022 ---------------------------
5024 The implementation of U-Boot is complicated by the fact that U-Boot
5025 starts running out of ROM (flash memory), usually without access to
5026 system RAM (because the memory controller is not initialized yet).
5027 This means that we don't have writable Data or BSS segments, and BSS
5028 is not initialized as zero. To be able to get a C environment working
5029 at all, we have to allocate at least a minimal stack. Implementation
5030 options for this are defined and restricted by the CPU used: Some CPU
5031 models provide on-chip memory (like the IMMR area on MPC8xx and
5032 MPC826x processors), on others (parts of) the data cache can be
5033 locked as (mis-) used as memory, etc.
5035 Chris Hallinan posted a good summary of these issues to the
5036 U-Boot mailing list:
5038 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5039 From: "Chris Hallinan" <clh@net1plus.com>
5040 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5043 Correct me if I'm wrong, folks, but the way I understand it
5044 is this: Using DCACHE as initial RAM for Stack, etc, does not
5045 require any physical RAM backing up the cache. The cleverness
5046 is that the cache is being used as a temporary supply of
5047 necessary storage before the SDRAM controller is setup. It's
5048 beyond the scope of this list to explain the details, but you
5049 can see how this works by studying the cache architecture and
5050 operation in the architecture and processor-specific manuals.
5052 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5053 is another option for the system designer to use as an
5054 initial stack/RAM area prior to SDRAM being available. Either
5055 option should work for you. Using CS 4 should be fine if your
5056 board designers haven't used it for something that would
5057 cause you grief during the initial boot! It is frequently not
5060 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5061 with your processor/board/system design. The default value
5062 you will find in any recent u-boot distribution in
5063 walnut.h should work for you. I'd set it to a value larger
5064 than your SDRAM module. If you have a 64MB SDRAM module, set
5065 it above 400_0000. Just make sure your board has no resources
5066 that are supposed to respond to that address! That code in
5067 start.S has been around a while and should work as is when
5068 you get the config right.
5073 It is essential to remember this, since it has some impact on the C
5074 code for the initialization procedures:
5076 * Initialized global data (data segment) is read-only. Do not attempt
5079 * Do not use any uninitialized global data (or implicitly initialized
5080 as zero data - BSS segment) at all - this is undefined, initiali-
5081 zation is performed later (when relocating to RAM).
5083 * Stack space is very limited. Avoid big data buffers or things like
5086 Having only the stack as writable memory limits means we cannot use
5087 normal global data to share information between the code. But it
5088 turned out that the implementation of U-Boot can be greatly
5089 simplified by making a global data structure (gd_t) available to all
5090 functions. We could pass a pointer to this data as argument to _all_
5091 functions, but this would bloat the code. Instead we use a feature of
5092 the GCC compiler (Global Register Variables) to share the data: we
5093 place a pointer (gd) to the global data into a register which we
5094 reserve for this purpose.
5096 When choosing a register for such a purpose we are restricted by the
5097 relevant (E)ABI specifications for the current architecture, and by
5098 GCC's implementation.
5100 For PowerPC, the following registers have specific use:
5102 R2: reserved for system use
5103 R3-R4: parameter passing and return values
5104 R5-R10: parameter passing
5105 R13: small data area pointer
5109 (U-Boot also uses R12 as internal GOT pointer. r12
5110 is a volatile register so r12 needs to be reset when
5111 going back and forth between asm and C)
5113 ==> U-Boot will use R2 to hold a pointer to the global data
5115 Note: on PPC, we could use a static initializer (since the
5116 address of the global data structure is known at compile time),
5117 but it turned out that reserving a register results in somewhat
5118 smaller code - although the code savings are not that big (on
5119 average for all boards 752 bytes for the whole U-Boot image,
5120 624 text + 127 data).
5122 On ARM, the following registers are used:
5124 R0: function argument word/integer result
5125 R1-R3: function argument word
5126 R9: platform specific
5127 R10: stack limit (used only if stack checking is enabled)
5128 R11: argument (frame) pointer
5129 R12: temporary workspace
5132 R15: program counter
5134 ==> U-Boot will use R9 to hold a pointer to the global data
5136 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5138 On Nios II, the ABI is documented here:
5139 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5141 ==> U-Boot will use gp to hold a pointer to the global data
5143 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5144 to access small data sections, so gp is free.
5146 On NDS32, the following registers are used:
5148 R0-R1: argument/return
5150 R15: temporary register for assembler
5151 R16: trampoline register
5152 R28: frame pointer (FP)
5153 R29: global pointer (GP)
5154 R30: link register (LP)
5155 R31: stack pointer (SP)
5156 PC: program counter (PC)
5158 ==> U-Boot will use R10 to hold a pointer to the global data
5160 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5161 or current versions of GCC may "optimize" the code too much.
5166 U-Boot runs in system state and uses physical addresses, i.e. the
5167 MMU is not used either for address mapping nor for memory protection.
5169 The available memory is mapped to fixed addresses using the memory
5170 controller. In this process, a contiguous block is formed for each
5171 memory type (Flash, SDRAM, SRAM), even when it consists of several
5172 physical memory banks.
5174 U-Boot is installed in the first 128 kB of the first Flash bank (on
5175 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5176 booting and sizing and initializing DRAM, the code relocates itself
5177 to the upper end of DRAM. Immediately below the U-Boot code some
5178 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5179 configuration setting]. Below that, a structure with global Board
5180 Info data is placed, followed by the stack (growing downward).
5182 Additionally, some exception handler code is copied to the low 8 kB
5183 of DRAM (0x00000000 ... 0x00001FFF).
5185 So a typical memory configuration with 16 MB of DRAM could look like
5188 0x0000 0000 Exception Vector code
5191 0x0000 2000 Free for Application Use
5197 0x00FB FF20 Monitor Stack (Growing downward)
5198 0x00FB FFAC Board Info Data and permanent copy of global data
5199 0x00FC 0000 Malloc Arena
5202 0x00FE 0000 RAM Copy of Monitor Code
5203 ... eventually: LCD or video framebuffer
5204 ... eventually: pRAM (Protected RAM - unchanged by reset)
5205 0x00FF FFFF [End of RAM]
5208 System Initialization:
5209 ----------------------
5211 In the reset configuration, U-Boot starts at the reset entry point
5212 (on most PowerPC systems at address 0x00000100). Because of the reset
5213 configuration for CS0# this is a mirror of the on board Flash memory.
5214 To be able to re-map memory U-Boot then jumps to its link address.
5215 To be able to implement the initialization code in C, a (small!)
5216 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5217 which provide such a feature like), or in a locked part of the data
5218 cache. After that, U-Boot initializes the CPU core, the caches and
5221 Next, all (potentially) available memory banks are mapped using a
5222 preliminary mapping. For example, we put them on 512 MB boundaries
5223 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5224 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5225 programmed for SDRAM access. Using the temporary configuration, a
5226 simple memory test is run that determines the size of the SDRAM
5229 When there is more than one SDRAM bank, and the banks are of
5230 different size, the largest is mapped first. For equal size, the first
5231 bank (CS2#) is mapped first. The first mapping is always for address
5232 0x00000000, with any additional banks following immediately to create
5233 contiguous memory starting from 0.
5235 Then, the monitor installs itself at the upper end of the SDRAM area
5236 and allocates memory for use by malloc() and for the global Board
5237 Info data; also, the exception vector code is copied to the low RAM
5238 pages, and the final stack is set up.
5240 Only after this relocation will you have a "normal" C environment;
5241 until that you are restricted in several ways, mostly because you are
5242 running from ROM, and because the code will have to be relocated to a
5246 U-Boot Porting Guide:
5247 ----------------------
5249 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5253 int main(int argc, char *argv[])
5255 sighandler_t no_more_time;
5257 signal(SIGALRM, no_more_time);
5258 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5260 if (available_money > available_manpower) {
5261 Pay consultant to port U-Boot;
5265 Download latest U-Boot source;
5267 Subscribe to u-boot mailing list;
5270 email("Hi, I am new to U-Boot, how do I get started?");
5273 Read the README file in the top level directory;
5274 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5275 Read applicable doc/*.README;
5276 Read the source, Luke;
5277 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5280 if (available_money > toLocalCurrency ($2500))
5283 Add a lot of aggravation and time;
5285 if (a similar board exists) { /* hopefully... */
5286 cp -a board/<similar> board/<myboard>
5287 cp include/configs/<similar>.h include/configs/<myboard>.h
5289 Create your own board support subdirectory;
5290 Create your own board include/configs/<myboard>.h file;
5292 Edit new board/<myboard> files
5293 Edit new include/configs/<myboard>.h
5298 Add / modify source code;
5302 email("Hi, I am having problems...");
5304 Send patch file to the U-Boot email list;
5305 if (reasonable critiques)
5306 Incorporate improvements from email list code review;
5308 Defend code as written;
5314 void no_more_time (int sig)
5323 All contributions to U-Boot should conform to the Linux kernel
5324 coding style; see the file "Documentation/CodingStyle" and the script
5325 "scripts/Lindent" in your Linux kernel source directory.
5327 Source files originating from a different project (for example the
5328 MTD subsystem) are generally exempt from these guidelines and are not
5329 reformatted to ease subsequent migration to newer versions of those
5332 Please note that U-Boot is implemented in C (and to some small parts in
5333 Assembler); no C++ is used, so please do not use C++ style comments (//)
5336 Please also stick to the following formatting rules:
5337 - remove any trailing white space
5338 - use TAB characters for indentation and vertical alignment, not spaces
5339 - make sure NOT to use DOS '\r\n' line feeds
5340 - do not add more than 2 consecutive empty lines to source files
5341 - do not add trailing empty lines to source files
5343 Submissions which do not conform to the standards may be returned
5344 with a request to reformat the changes.
5350 Since the number of patches for U-Boot is growing, we need to
5351 establish some rules. Submissions which do not conform to these rules
5352 may be rejected, even when they contain important and valuable stuff.
5354 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5356 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5357 see http://lists.denx.de/mailman/listinfo/u-boot
5359 When you send a patch, please include the following information with
5362 * For bug fixes: a description of the bug and how your patch fixes
5363 this bug. Please try to include a way of demonstrating that the
5364 patch actually fixes something.
5366 * For new features: a description of the feature and your
5369 * A CHANGELOG entry as plaintext (separate from the patch)
5371 * For major contributions, add a MAINTAINERS file with your
5372 information and associated file and directory references.
5374 * When you add support for a new board, don't forget to add a
5375 maintainer e-mail address to the boards.cfg file, too.
5377 * If your patch adds new configuration options, don't forget to
5378 document these in the README file.
5380 * The patch itself. If you are using git (which is *strongly*
5381 recommended) you can easily generate the patch using the
5382 "git format-patch". If you then use "git send-email" to send it to
5383 the U-Boot mailing list, you will avoid most of the common problems
5384 with some other mail clients.
5386 If you cannot use git, use "diff -purN OLD NEW". If your version of
5387 diff does not support these options, then get the latest version of
5390 The current directory when running this command shall be the parent
5391 directory of the U-Boot source tree (i. e. please make sure that
5392 your patch includes sufficient directory information for the
5395 We prefer patches as plain text. MIME attachments are discouraged,
5396 and compressed attachments must not be used.
5398 * If one logical set of modifications affects or creates several
5399 files, all these changes shall be submitted in a SINGLE patch file.
5401 * Changesets that contain different, unrelated modifications shall be
5402 submitted as SEPARATE patches, one patch per changeset.
5407 * Before sending the patch, run the buildman script on your patched
5408 source tree and make sure that no errors or warnings are reported
5409 for any of the boards.
5411 * Keep your modifications to the necessary minimum: A patch
5412 containing several unrelated changes or arbitrary reformats will be
5413 returned with a request to re-formatting / split it.
5415 * If you modify existing code, make sure that your new code does not
5416 add to the memory footprint of the code ;-) Small is beautiful!
5417 When adding new features, these should compile conditionally only
5418 (using #ifdef), and the resulting code with the new feature
5419 disabled must not need more memory than the old code without your
5422 * Remember that there is a size limit of 100 kB per message on the
5423 u-boot mailing list. Bigger patches will be moderated. If they are
5424 reasonable and not too big, they will be acknowledged. But patches
5425 bigger than the size limit should be avoided.