2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /m68k Files generic to m68k architecture
140 /microblaze Files generic to microblaze architecture
141 /mips Files generic to MIPS architecture
142 /nds32 Files generic to NDS32 architecture
143 /nios2 Files generic to Altera NIOS2 architecture
144 /openrisc Files generic to OpenRISC architecture
145 /powerpc Files generic to PowerPC architecture
146 /sandbox Files generic to HW-independent "sandbox"
147 /sh Files generic to SH architecture
148 /x86 Files generic to x86 architecture
149 /api Machine/arch independent API for external apps
150 /board Board dependent files
151 /cmd U-Boot commands functions
152 /common Misc architecture independent functions
153 /configs Board default configuration files
154 /disk Code for disk drive partition handling
155 /doc Documentation (don't expect too much)
156 /drivers Commonly used device drivers
157 /dts Contains Makefile for building internal U-Boot fdt.
158 /examples Example code for standalone applications, etc.
159 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
160 /include Header Files
161 /lib Library routines generic to all architectures
162 /Licenses Various license files
164 /post Power On Self Test
165 /scripts Various build scripts and Makefiles
166 /test Various unit test files
167 /tools Tools to build S-Record or U-Boot images, etc.
169 Software Configuration:
170 =======================
172 Configuration is usually done using C preprocessor defines; the
173 rationale behind that is to avoid dead code whenever possible.
175 There are two classes of configuration variables:
177 * Configuration _OPTIONS_:
178 These are selectable by the user and have names beginning with
181 * Configuration _SETTINGS_:
182 These depend on the hardware etc. and should not be meddled with if
183 you don't know what you're doing; they have names beginning with
186 Previously, all configuration was done by hand, which involved creating
187 symbolic links and editing configuration files manually. More recently,
188 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
189 allowing you to use the "make menuconfig" command to configure your
193 Selection of Processor Architecture and Board Type:
194 ---------------------------------------------------
196 For all supported boards there are ready-to-use default
197 configurations available; just type "make <board_name>_defconfig".
199 Example: For a TQM823L module type:
202 make TQM823L_defconfig
204 Note: If you're looking for the default configuration file for a board
205 you're sure used to be there but is now missing, check the file
206 doc/README.scrapyard for a list of no longer supported boards.
211 U-Boot can be built natively to run on a Linux host using the 'sandbox'
212 board. This allows feature development which is not board- or architecture-
213 specific to be undertaken on a native platform. The sandbox is also used to
214 run some of U-Boot's tests.
216 See board/sandbox/README.sandbox for more details.
219 Board Initialisation Flow:
220 --------------------------
222 This is the intended start-up flow for boards. This should apply for both
223 SPL and U-Boot proper (i.e. they both follow the same rules).
225 Note: "SPL" stands for "Secondary Program Loader," which is explained in
226 more detail later in this file.
228 At present, SPL mostly uses a separate code path, but the function names
229 and roles of each function are the same. Some boards or architectures
230 may not conform to this. At least most ARM boards which use
231 CONFIG_SPL_FRAMEWORK conform to this.
233 Execution typically starts with an architecture-specific (and possibly
234 CPU-specific) start.S file, such as:
236 - arch/arm/cpu/armv7/start.S
237 - arch/powerpc/cpu/mpc83xx/start.S
238 - arch/mips/cpu/start.S
240 and so on. From there, three functions are called; the purpose and
241 limitations of each of these functions are described below.
244 - purpose: essential init to permit execution to reach board_init_f()
245 - no global_data or BSS
246 - there is no stack (ARMv7 may have one but it will soon be removed)
247 - must not set up SDRAM or use console
248 - must only do the bare minimum to allow execution to continue to
250 - this is almost never needed
251 - return normally from this function
254 - purpose: set up the machine ready for running board_init_r():
255 i.e. SDRAM and serial UART
256 - global_data is available
258 - BSS is not available, so you cannot use global/static variables,
259 only stack variables and global_data
261 Non-SPL-specific notes:
262 - dram_init() is called to set up DRAM. If already done in SPL this
266 - you can override the entire board_init_f() function with your own
268 - preloader_console_init() can be called here in extremis
269 - should set up SDRAM, and anything needed to make the UART work
270 - these is no need to clear BSS, it will be done by crt0.S
271 - must return normally from this function (don't call board_init_r()
274 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
275 this point the stack and global_data are relocated to below
276 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
280 - purpose: main execution, common code
281 - global_data is available
283 - BSS is available, all static/global variables can be used
284 - execution eventually continues to main_loop()
286 Non-SPL-specific notes:
287 - U-Boot is relocated to the top of memory and is now running from
291 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
292 CONFIG_SPL_STACK_R_ADDR points into SDRAM
293 - preloader_console_init() can be called here - typically this is
294 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
295 spl_board_init() function containing this call
296 - loads U-Boot or (in falcon mode) Linux
300 Configuration Options:
301 ----------------------
303 Configuration depends on the combination of board and CPU type; all
304 such information is kept in a configuration file
305 "include/configs/<board_name>.h".
307 Example: For a TQM823L module, all configuration settings are in
308 "include/configs/TQM823L.h".
311 Many of the options are named exactly as the corresponding Linux
312 kernel configuration options. The intention is to make it easier to
313 build a config tool - later.
316 The following options need to be configured:
318 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
320 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
322 - Marvell Family Member
323 CONFIG_SYS_MVFS - define it if you want to enable
324 multiple fs option at one time
325 for marvell soc family
330 Specifies that the core is a 64-bit PowerPC implementation (implements
331 the "64" category of the Power ISA). This is necessary for ePAPR
332 compliance, among other possible reasons.
334 CONFIG_SYS_FSL_TBCLK_DIV
336 Defines the core time base clock divider ratio compared to the
337 system clock. On most PQ3 devices this is 8, on newer QorIQ
338 devices it can be 16 or 32. The ratio varies from SoC to Soc.
340 CONFIG_SYS_FSL_PCIE_COMPAT
342 Defines the string to utilize when trying to match PCIe device
343 tree nodes for the given platform.
345 CONFIG_SYS_FSL_ERRATUM_A004510
347 Enables a workaround for erratum A004510. If set,
348 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
349 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
351 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
352 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
354 Defines one or two SoC revisions (low 8 bits of SVR)
355 for which the A004510 workaround should be applied.
357 The rest of SVR is either not relevant to the decision
358 of whether the erratum is present (e.g. p2040 versus
359 p2041) or is implied by the build target, which controls
360 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
362 See Freescale App Note 4493 for more information about
365 CONFIG_A003399_NOR_WORKAROUND
366 Enables a workaround for IFC erratum A003399. It is only
367 required during NOR boot.
369 CONFIG_A008044_WORKAROUND
370 Enables a workaround for T1040/T1042 erratum A008044. It is only
371 required during NAND boot and valid for Rev 1.0 SoC revision
373 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
375 This is the value to write into CCSR offset 0x18600
376 according to the A004510 workaround.
378 CONFIG_SYS_FSL_DSP_DDR_ADDR
379 This value denotes start offset of DDR memory which is
380 connected exclusively to the DSP cores.
382 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
383 This value denotes start offset of M2 memory
384 which is directly connected to the DSP core.
386 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
387 This value denotes start offset of M3 memory which is directly
388 connected to the DSP core.
390 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
391 This value denotes start offset of DSP CCSR space.
393 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
394 Single Source Clock is clocking mode present in some of FSL SoC's.
395 In this mode, a single differential clock is used to supply
396 clocks to the sysclock, ddrclock and usbclock.
398 CONFIG_SYS_CPC_REINIT_F
399 This CONFIG is defined when the CPC is configured as SRAM at the
400 time of U-Boot entry and is required to be re-initialized.
403 Indicates this SoC supports deep sleep feature. If deep sleep is
404 supported, core will start to execute uboot when wakes up.
406 - Generic CPU options:
407 CONFIG_SYS_GENERIC_GLOBAL_DATA
408 Defines global data is initialized in generic board board_init_f().
409 If this macro is defined, global data is created and cleared in
410 generic board board_init_f(). Without this macro, architecture/board
411 should initialize global data before calling board_init_f().
413 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
415 Defines the endianess of the CPU. Implementation of those
416 values is arch specific.
419 Freescale DDR driver in use. This type of DDR controller is
420 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
423 CONFIG_SYS_FSL_DDR_ADDR
424 Freescale DDR memory-mapped register base.
426 CONFIG_SYS_FSL_DDR_EMU
427 Specify emulator support for DDR. Some DDR features such as
428 deskew training are not available.
430 CONFIG_SYS_FSL_DDRC_GEN1
431 Freescale DDR1 controller.
433 CONFIG_SYS_FSL_DDRC_GEN2
434 Freescale DDR2 controller.
436 CONFIG_SYS_FSL_DDRC_GEN3
437 Freescale DDR3 controller.
439 CONFIG_SYS_FSL_DDRC_GEN4
440 Freescale DDR4 controller.
442 CONFIG_SYS_FSL_DDRC_ARM_GEN3
443 Freescale DDR3 controller for ARM-based SoCs.
446 Board config to use DDR1. It can be enabled for SoCs with
447 Freescale DDR1 or DDR2 controllers, depending on the board
451 Board config to use DDR2. It can be enabled for SoCs with
452 Freescale DDR2 or DDR3 controllers, depending on the board
456 Board config to use DDR3. It can be enabled for SoCs with
457 Freescale DDR3 or DDR3L controllers.
460 Board config to use DDR3L. It can be enabled for SoCs with
464 Board config to use DDR4. It can be enabled for SoCs with
467 CONFIG_SYS_FSL_IFC_BE
468 Defines the IFC controller register space as Big Endian
470 CONFIG_SYS_FSL_IFC_LE
471 Defines the IFC controller register space as Little Endian
473 CONFIG_SYS_FSL_IFC_CLK_DIV
474 Defines divider of platform clock(clock input to IFC controller).
476 CONFIG_SYS_FSL_LBC_CLK_DIV
477 Defines divider of platform clock(clock input to eLBC controller).
479 CONFIG_SYS_FSL_PBL_PBI
480 It enables addition of RCW (Power on reset configuration) in built image.
481 Please refer doc/README.pblimage for more details
483 CONFIG_SYS_FSL_PBL_RCW
484 It adds PBI(pre-boot instructions) commands in u-boot build image.
485 PBI commands can be used to configure SoC before it starts the execution.
486 Please refer doc/README.pblimage for more details
489 It adds a target to create boot binary having SPL binary in PBI format
490 concatenated with u-boot binary.
492 CONFIG_SYS_FSL_DDR_BE
493 Defines the DDR controller register space as Big Endian
495 CONFIG_SYS_FSL_DDR_LE
496 Defines the DDR controller register space as Little Endian
498 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
499 Physical address from the view of DDR controllers. It is the
500 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
501 it could be different for ARM SoCs.
503 CONFIG_SYS_FSL_DDR_INTLV_256B
504 DDR controller interleaving on 256-byte. This is a special
505 interleaving mode, handled by Dickens for Freescale layerscape
508 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
509 Number of controllers used as main memory.
511 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
512 Number of controllers used for other than main memory.
514 CONFIG_SYS_FSL_HAS_DP_DDR
515 Defines the SoC has DP-DDR used for DPAA.
517 CONFIG_SYS_FSL_SEC_BE
518 Defines the SEC controller register space as Big Endian
520 CONFIG_SYS_FSL_SEC_LE
521 Defines the SEC controller register space as Little Endian
524 CONFIG_SYS_INIT_SP_OFFSET
526 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
527 pointer. This is needed for the temporary stack before
530 CONFIG_SYS_MIPS_CACHE_MODE
532 Cache operation mode for the MIPS CPU.
533 See also arch/mips/include/asm/mipsregs.h.
535 CONF_CM_CACHABLE_NO_WA
538 CONF_CM_CACHABLE_NONCOHERENT
542 CONF_CM_CACHABLE_ACCELERATED
544 CONFIG_SYS_XWAY_EBU_BOOTCFG
546 Special option for Lantiq XWAY SoCs for booting from NOR flash.
547 See also arch/mips/cpu/mips32/start.S.
549 CONFIG_XWAY_SWAP_BYTES
551 Enable compilation of tools/xway-swap-bytes needed for Lantiq
552 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
553 be swapped if a flash programmer is used.
556 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
558 Select high exception vectors of the ARM core, e.g., do not
559 clear the V bit of the c1 register of CP15.
562 Generic timer clock source frequency.
564 COUNTER_FREQUENCY_REAL
565 Generic timer clock source frequency if the real clock is
566 different from COUNTER_FREQUENCY, and can only be determined
570 CONFIG_TEGRA_SUPPORT_NON_SECURE
572 Support executing U-Boot in non-secure (NS) mode. Certain
573 impossible actions will be skipped if the CPU is in NS mode,
574 such as ARM architectural timer initialization.
576 - Linux Kernel Interface:
579 U-Boot stores all clock information in Hz
580 internally. For binary compatibility with older Linux
581 kernels (which expect the clocks passed in the
582 bd_info data to be in MHz) the environment variable
583 "clocks_in_mhz" can be defined so that U-Boot
584 converts clock data to MHZ before passing it to the
586 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
587 "clocks_in_mhz=1" is automatically included in the
590 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
592 When transferring memsize parameter to Linux, some versions
593 expect it to be in bytes, others in MB.
594 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
598 New kernel versions are expecting firmware settings to be
599 passed using flattened device trees (based on open firmware
603 * New libfdt-based support
604 * Adds the "fdt" command
605 * The bootm command automatically updates the fdt
607 OF_TBCLK - The timebase frequency.
608 OF_STDOUT_PATH - The path to the console device
610 boards with QUICC Engines require OF_QE to set UCC MAC
613 CONFIG_OF_BOARD_SETUP
615 Board code has addition modification that it wants to make
616 to the flat device tree before handing it off to the kernel
618 CONFIG_OF_SYSTEM_SETUP
620 Other code has addition modification that it wants to make
621 to the flat device tree before handing it off to the kernel.
622 This causes ft_system_setup() to be called before booting
627 U-Boot can detect if an IDE device is present or not.
628 If not, and this new config option is activated, U-Boot
629 removes the ATA node from the DTS before booting Linux,
630 so the Linux IDE driver does not probe the device and
631 crash. This is needed for buggy hardware (uc101) where
632 no pull down resistor is connected to the signal IDE5V_DD7.
634 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
636 This setting is mandatory for all boards that have only one
637 machine type and must be used to specify the machine type
638 number as it appears in the ARM machine registry
639 (see http://www.arm.linux.org.uk/developer/machines/).
640 Only boards that have multiple machine types supported
641 in a single configuration file and the machine type is
642 runtime discoverable, do not have to use this setting.
644 - vxWorks boot parameters:
646 bootvx constructs a valid bootline using the following
647 environments variables: bootdev, bootfile, ipaddr, netmask,
648 serverip, gatewayip, hostname, othbootargs.
649 It loads the vxWorks image pointed bootfile.
651 Note: If a "bootargs" environment is defined, it will overwride
652 the defaults discussed just above.
654 - Cache Configuration:
655 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
656 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
657 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
659 - Cache Configuration for ARM:
660 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
662 CONFIG_SYS_PL310_BASE - Physical base address of PL310
663 controller register space
668 Define this if you want support for Amba PrimeCell PL010 UARTs.
672 Define this if you want support for Amba PrimeCell PL011 UARTs.
676 If you have Amba PrimeCell PL011 UARTs, set this variable to
677 the clock speed of the UARTs.
681 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
682 define this to a list of base addresses for each (supported)
683 port. See e.g. include/configs/versatile.h
685 CONFIG_SERIAL_HW_FLOW_CONTROL
687 Define this variable to enable hw flow control in serial driver.
688 Current user of this option is drivers/serial/nsl16550.c driver
691 CONFIG_BAUDRATE - in bps
692 Select one of the baudrates listed in
693 CONFIG_SYS_BAUDRATE_TABLE, see below.
697 Only needed when CONFIG_BOOTDELAY is enabled;
698 define a command string that is automatically executed
699 when no character is read on the console interface
700 within "Boot Delay" after reset.
703 This can be used to pass arguments to the bootm
704 command. The value of CONFIG_BOOTARGS goes into the
705 environment value "bootargs".
707 CONFIG_RAMBOOT and CONFIG_NFSBOOT
708 The value of these goes into the environment as
709 "ramboot" and "nfsboot" respectively, and can be used
710 as a convenience, when switching between booting from
714 CONFIG_BOOTCOUNT_LIMIT
715 Implements a mechanism for detecting a repeating reboot
717 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
720 If no softreset save registers are found on the hardware
721 "bootcount" is stored in the environment. To prevent a
722 saveenv on all reboots, the environment variable
723 "upgrade_available" is used. If "upgrade_available" is
724 0, "bootcount" is always 0, if "upgrade_available" is
725 1 "bootcount" is incremented in the environment.
726 So the Userspace Applikation must set the "upgrade_available"
727 and "bootcount" variable to 0, if a boot was successfully.
732 When this option is #defined, the existence of the
733 environment variable "preboot" will be checked
734 immediately before starting the CONFIG_BOOTDELAY
735 countdown and/or running the auto-boot command resp.
736 entering interactive mode.
738 This feature is especially useful when "preboot" is
739 automatically generated or modified. For an example
740 see the LWMON board specific code: here "preboot" is
741 modified when the user holds down a certain
742 combination of keys on the (special) keyboard when
745 - Serial Download Echo Mode:
747 If defined to 1, all characters received during a
748 serial download (using the "loads" command) are
749 echoed back. This might be needed by some terminal
750 emulations (like "cu"), but may as well just take
751 time on others. This setting #define's the initial
752 value of the "loads_echo" environment variable.
754 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
756 Select one of the baudrates listed in
757 CONFIG_SYS_BAUDRATE_TABLE, see below.
760 Monitor commands can be included or excluded
761 from the build by using the #include files
762 <config_cmd_all.h> and #undef'ing unwanted
763 commands, or adding #define's for wanted commands.
765 The default command configuration includes all commands
766 except those marked below with a "*".
768 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
769 CONFIG_CMD_ASKENV * ask for env variable
770 CONFIG_CMD_BDI bdinfo
771 CONFIG_CMD_BOOTD bootd
772 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
773 CONFIG_CMD_CACHE * icache, dcache
774 CONFIG_CMD_CONSOLE coninfo
775 CONFIG_CMD_DHCP * DHCP support
776 CONFIG_CMD_DIAG * Diagnostics
777 CONFIG_CMD_ECHO echo arguments
778 CONFIG_CMD_EDITENV edit env variable
779 CONFIG_CMD_ELF * bootelf, bootvx
780 CONFIG_CMD_ENV_EXISTS * check existence of env variable
781 CONFIG_CMD_EXPORTENV * export the environment
782 CONFIG_CMD_EXT2 * ext2 command support
783 CONFIG_CMD_EXT4 * ext4 command support
784 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
785 that work for multiple fs types
786 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
787 CONFIG_CMD_SAVEENV saveenv
788 CONFIG_CMD_FLASH flinfo, erase, protect
789 CONFIG_CMD_FPGA FPGA device initialization support
790 CONFIG_CMD_GO * the 'go' command (exec code)
791 CONFIG_CMD_GREPENV * search environment
792 CONFIG_CMD_I2C * I2C serial bus support
793 CONFIG_CMD_IMI iminfo
794 CONFIG_CMD_IMLS List all images found in NOR flash
795 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
796 CONFIG_CMD_IMPORTENV * import an environment
797 CONFIG_CMD_INI * import data from an ini file into the env
798 CONFIG_CMD_ITEST Integer/string test of 2 values
799 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
800 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
802 CONFIG_CMD_LOADB loadb
803 CONFIG_CMD_LOADS loads
804 CONFIG_CMD_MD5SUM * print md5 message digest
805 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
806 CONFIG_CMD_MEMINFO * Display detailed memory information
807 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
809 CONFIG_CMD_MEMTEST * mtest
810 CONFIG_CMD_MISC Misc functions like sleep etc
811 CONFIG_CMD_MMC * MMC memory mapped support
812 CONFIG_CMD_MII * MII utility commands
813 CONFIG_CMD_NET bootp, tftpboot, rarpboot
814 CONFIG_CMD_NFS NFS support
815 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
817 CONFIG_CMD_RUN run command in env variable
818 CONFIG_CMD_SDRAM * print SDRAM configuration information
819 (requires CONFIG_CMD_I2C)
820 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
821 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
822 CONFIG_CMD_SOURCE "source" command Support
823 CONFIG_CMD_SPI * SPI serial bus support
824 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
825 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
826 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
827 CONFIG_CMD_TIMER * access to the system tick timer
828 CONFIG_CMD_USB * USB support
829 CONFIG_CMD_CDP * Cisco Discover Protocol support
830 CONFIG_CMD_XIMG Load part of Multi Image
831 CONFIG_CMD_UUID * Generate random UUID or GUID string
833 EXAMPLE: If you want all functions except of network
834 support you can write:
836 #include "config_cmd_all.h"
837 #undef CONFIG_CMD_NET
840 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
842 Note: Don't enable the "icache" and "dcache" commands
843 (configuration option CONFIG_CMD_CACHE) unless you know
844 what you (and your U-Boot users) are doing. Data
845 cache cannot be enabled on systems like the
846 8xx (where accesses to the IMMR region must be
847 uncached), and it cannot be disabled on all other
848 systems where we (mis-) use the data cache to hold an
849 initial stack and some data.
852 XXX - this list needs to get updated!
854 - Removal of commands
855 If no commands are needed to boot, you can disable
856 CONFIG_CMDLINE to remove them. In this case, the command line
857 will not be available, and when U-Boot wants to execute the
858 boot command (on start-up) it will call board_run_command()
859 instead. This can reduce image size significantly for very
860 simple boot procedures.
862 - Regular expression support:
864 If this variable is defined, U-Boot is linked against
865 the SLRE (Super Light Regular Expression) library,
866 which adds regex support to some commands, as for
867 example "env grep" and "setexpr".
871 If this variable is defined, U-Boot will use a device tree
872 to configure its devices, instead of relying on statically
873 compiled #defines in the board file. This option is
874 experimental and only available on a few boards. The device
875 tree is available in the global data as gd->fdt_blob.
877 U-Boot needs to get its device tree from somewhere. This can
878 be done using one of the three options below:
881 If this variable is defined, U-Boot will embed a device tree
882 binary in its image. This device tree file should be in the
883 board directory and called <soc>-<board>.dts. The binary file
884 is then picked up in board_init_f() and made available through
885 the global data structure as gd->blob.
888 If this variable is defined, U-Boot will build a device tree
889 binary. It will be called u-boot.dtb. Architecture-specific
890 code will locate it at run-time. Generally this works by:
892 cat u-boot.bin u-boot.dtb >image.bin
894 and in fact, U-Boot does this for you, creating a file called
895 u-boot-dtb.bin which is useful in the common case. You can
896 still use the individual files if you need something more
900 If this variable is defined, U-Boot will use the device tree
901 provided by the board at runtime instead of embedding one with
902 the image. Only boards defining board_fdt_blob_setup() support
903 this option (see include/fdtdec.h file).
907 If this variable is defined, it enables watchdog
908 support for the SoC. There must be support in the SoC
909 specific code for a watchdog. For the 8xx
910 CPUs, the SIU Watchdog feature is enabled in the SYPCR
911 register. When supported for a specific SoC is
912 available, then no further board specific code should
916 When using a watchdog circuitry external to the used
917 SoC, then define this variable and provide board
918 specific code for the "hw_watchdog_reset" function.
920 CONFIG_AT91_HW_WDT_TIMEOUT
921 specify the timeout in seconds. default 2 seconds.
924 CONFIG_VERSION_VARIABLE
925 If this variable is defined, an environment variable
926 named "ver" is created by U-Boot showing the U-Boot
927 version as printed by the "version" command.
928 Any change to this variable will be reverted at the
933 When CONFIG_CMD_DATE is selected, the type of the RTC
934 has to be selected, too. Define exactly one of the
937 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
938 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
939 CONFIG_RTC_MC146818 - use MC146818 RTC
940 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
941 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
942 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
943 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
944 CONFIG_RTC_DS164x - use Dallas DS164x RTC
945 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
946 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
947 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
948 CONFIG_SYS_RV3029_TCR - enable trickle charger on
951 Note that if the RTC uses I2C, then the I2C interface
952 must also be configured. See I2C Support, below.
955 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
957 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
958 chip-ngpio pairs that tell the PCA953X driver the number of
959 pins supported by a particular chip.
961 Note that if the GPIO device uses I2C, then the I2C interface
962 must also be configured. See I2C Support, below.
965 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
966 accesses and can checksum them or write a list of them out
967 to memory. See the 'iotrace' command for details. This is
968 useful for testing device drivers since it can confirm that
969 the driver behaves the same way before and after a code
970 change. Currently this is supported on sandbox and arm. To
971 add support for your architecture, add '#include <iotrace.h>'
972 to the bottom of arch/<arch>/include/asm/io.h and test.
974 Example output from the 'iotrace stats' command is below.
975 Note that if the trace buffer is exhausted, the checksum will
976 still continue to operate.
979 Start: 10000000 (buffer start address)
980 Size: 00010000 (buffer size)
981 Offset: 00000120 (current buffer offset)
982 Output: 10000120 (start + offset)
983 Count: 00000018 (number of trace records)
984 CRC32: 9526fb66 (CRC32 of all trace records)
988 When CONFIG_TIMESTAMP is selected, the timestamp
989 (date and time) of an image is printed by image
990 commands like bootm or iminfo. This option is
991 automatically enabled when you select CONFIG_CMD_DATE .
993 - Partition Labels (disklabels) Supported:
994 Zero or more of the following:
995 CONFIG_MAC_PARTITION Apple's MacOS partition table.
996 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
997 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
998 bootloader. Note 2TB partition limit; see
1000 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1002 If IDE or SCSI support is enabled (CONFIG_IDE or
1003 CONFIG_SCSI) you must configure support for at
1004 least one non-MTD partition type as well.
1007 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1008 board configurations files but used nowhere!
1010 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1011 be performed by calling the function
1012 ide_set_reset(int reset)
1013 which has to be defined in a board specific file
1018 Set this to enable ATAPI support.
1023 Set this to enable support for disks larger than 137GB
1024 Also look at CONFIG_SYS_64BIT_LBA.
1025 Whithout these , LBA48 support uses 32bit variables and will 'only'
1026 support disks up to 2.1TB.
1028 CONFIG_SYS_64BIT_LBA:
1029 When enabled, makes the IDE subsystem use 64bit sector addresses.
1033 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1034 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1035 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1036 maximum numbers of LUNs, SCSI ID's and target
1039 The environment variable 'scsidevs' is set to the number of
1040 SCSI devices found during the last scan.
1042 - NETWORK Support (PCI):
1044 Support for Intel 8254x/8257x gigabit chips.
1047 Utility code for direct access to the SPI bus on Intel 8257x.
1048 This does not do anything useful unless you set at least one
1049 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1051 CONFIG_E1000_SPI_GENERIC
1052 Allow generic access to the SPI bus on the Intel 8257x, for
1053 example with the "sspi" command.
1056 Management command for E1000 devices. When used on devices
1057 with SPI support you can reprogram the EEPROM from U-Boot.
1060 Support for Intel 82557/82559/82559ER chips.
1061 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1062 write routine for first time initialisation.
1065 Support for Digital 2114x chips.
1066 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1067 modem chip initialisation (KS8761/QS6611).
1070 Support for National dp83815 chips.
1073 Support for National dp8382[01] gigabit chips.
1075 - NETWORK Support (other):
1077 CONFIG_DRIVER_AT91EMAC
1078 Support for AT91RM9200 EMAC.
1081 Define this to use reduced MII inteface
1083 CONFIG_DRIVER_AT91EMAC_QUIET
1084 If this defined, the driver is quiet.
1085 The driver doen't show link status messages.
1087 CONFIG_CALXEDA_XGMAC
1088 Support for the Calxeda XGMAC device
1091 Support for SMSC's LAN91C96 chips.
1093 CONFIG_LAN91C96_USE_32_BIT
1094 Define this to enable 32 bit addressing
1097 Support for SMSC's LAN91C111 chip
1099 CONFIG_SMC91111_BASE
1100 Define this to hold the physical address
1101 of the device (I/O space)
1103 CONFIG_SMC_USE_32_BIT
1104 Define this if data bus is 32 bits
1106 CONFIG_SMC_USE_IOFUNCS
1107 Define this to use i/o functions instead of macros
1108 (some hardware wont work with macros)
1110 CONFIG_DRIVER_TI_EMAC
1111 Support for davinci emac
1113 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1114 Define this if you have more then 3 PHYs.
1117 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1119 CONFIG_FTGMAC100_EGIGA
1120 Define this to use GE link update with gigabit PHY.
1121 Define this if FTGMAC100 is connected to gigabit PHY.
1122 If your system has 10/100 PHY only, it might not occur
1123 wrong behavior. Because PHY usually return timeout or
1124 useless data when polling gigabit status and gigabit
1125 control registers. This behavior won't affect the
1126 correctnessof 10/100 link speed update.
1129 Support for SMSC's LAN911x and LAN921x chips
1132 Define this to hold the physical address
1133 of the device (I/O space)
1135 CONFIG_SMC911X_32_BIT
1136 Define this if data bus is 32 bits
1138 CONFIG_SMC911X_16_BIT
1139 Define this if data bus is 16 bits. If your processor
1140 automatically converts one 32 bit word to two 16 bit
1141 words you may also try CONFIG_SMC911X_32_BIT.
1144 Support for Renesas on-chip Ethernet controller
1146 CONFIG_SH_ETHER_USE_PORT
1147 Define the number of ports to be used
1149 CONFIG_SH_ETHER_PHY_ADDR
1150 Define the ETH PHY's address
1152 CONFIG_SH_ETHER_CACHE_WRITEBACK
1153 If this option is set, the driver enables cache flush.
1157 Support for PWM module on the imx6.
1161 Support TPM devices.
1163 CONFIG_TPM_TIS_INFINEON
1164 Support for Infineon i2c bus TPM devices. Only one device
1165 per system is supported at this time.
1167 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1168 Define the burst count bytes upper limit
1171 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1173 CONFIG_TPM_ST33ZP24_I2C
1174 Support for STMicroelectronics ST33ZP24 I2C devices.
1175 Requires TPM_ST33ZP24 and I2C.
1177 CONFIG_TPM_ST33ZP24_SPI
1178 Support for STMicroelectronics ST33ZP24 SPI devices.
1179 Requires TPM_ST33ZP24 and SPI.
1181 CONFIG_TPM_ATMEL_TWI
1182 Support for Atmel TWI TPM device. Requires I2C support.
1185 Support for generic parallel port TPM devices. Only one device
1186 per system is supported at this time.
1188 CONFIG_TPM_TIS_BASE_ADDRESS
1189 Base address where the generic TPM device is mapped
1190 to. Contemporary x86 systems usually map it at
1194 Add tpm monitor functions.
1195 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1196 provides monitor access to authorized functions.
1199 Define this to enable the TPM support library which provides
1200 functional interfaces to some TPM commands.
1201 Requires support for a TPM device.
1203 CONFIG_TPM_AUTH_SESSIONS
1204 Define this to enable authorized functions in the TPM library.
1205 Requires CONFIG_TPM and CONFIG_SHA1.
1208 At the moment only the UHCI host controller is
1209 supported (PIP405, MIP405); define
1210 CONFIG_USB_UHCI to enable it.
1211 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1212 and define CONFIG_USB_STORAGE to enable the USB
1215 Supported are USB Keyboards and USB Floppy drives
1218 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1219 txfilltuning field in the EHCI controller on reset.
1221 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1222 HW module registers.
1225 Define the below if you wish to use the USB console.
1226 Once firmware is rebuilt from a serial console issue the
1227 command "setenv stdin usbtty; setenv stdout usbtty" and
1228 attach your USB cable. The Unix command "dmesg" should print
1229 it has found a new device. The environment variable usbtty
1230 can be set to gserial or cdc_acm to enable your device to
1231 appear to a USB host as a Linux gserial device or a
1232 Common Device Class Abstract Control Model serial device.
1233 If you select usbtty = gserial you should be able to enumerate
1235 # modprobe usbserial vendor=0xVendorID product=0xProductID
1236 else if using cdc_acm, simply setting the environment
1237 variable usbtty to be cdc_acm should suffice. The following
1238 might be defined in YourBoardName.h
1241 Define this to build a UDC device
1244 Define this to have a tty type of device available to
1245 talk to the UDC device
1248 Define this to enable the high speed support for usb
1249 device and usbtty. If this feature is enabled, a routine
1250 int is_usbd_high_speed(void)
1251 also needs to be defined by the driver to dynamically poll
1252 whether the enumeration has succeded at high speed or full
1255 CONFIG_SYS_CONSOLE_IS_IN_ENV
1256 Define this if you want stdin, stdout &/or stderr to
1259 If you have a USB-IF assigned VendorID then you may wish to
1260 define your own vendor specific values either in BoardName.h
1261 or directly in usbd_vendor_info.h. If you don't define
1262 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1263 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1264 should pretend to be a Linux device to it's target host.
1266 CONFIG_USBD_MANUFACTURER
1267 Define this string as the name of your company for
1268 - CONFIG_USBD_MANUFACTURER "my company"
1270 CONFIG_USBD_PRODUCT_NAME
1271 Define this string as the name of your product
1272 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1274 CONFIG_USBD_VENDORID
1275 Define this as your assigned Vendor ID from the USB
1276 Implementors Forum. This *must* be a genuine Vendor ID
1277 to avoid polluting the USB namespace.
1278 - CONFIG_USBD_VENDORID 0xFFFF
1280 CONFIG_USBD_PRODUCTID
1281 Define this as the unique Product ID
1283 - CONFIG_USBD_PRODUCTID 0xFFFF
1285 - ULPI Layer Support:
1286 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1287 the generic ULPI layer. The generic layer accesses the ULPI PHY
1288 via the platform viewport, so you need both the genric layer and
1289 the viewport enabled. Currently only Chipidea/ARC based
1290 viewport is supported.
1291 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1292 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1293 If your ULPI phy needs a different reference clock than the
1294 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1295 the appropriate value in Hz.
1298 The MMC controller on the Intel PXA is supported. To
1299 enable this define CONFIG_MMC. The MMC can be
1300 accessed from the boot prompt by mapping the device
1301 to physical memory similar to flash. Command line is
1302 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1303 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1306 Support for Renesas on-chip MMCIF controller
1308 CONFIG_SH_MMCIF_ADDR
1309 Define the base address of MMCIF registers
1312 Define the clock frequency for MMCIF
1314 CONFIG_SUPPORT_EMMC_BOOT
1315 Enable some additional features of the eMMC boot partitions.
1317 CONFIG_SUPPORT_EMMC_RPMB
1318 Enable the commands for reading, writing and programming the
1319 key for the Replay Protection Memory Block partition in eMMC.
1321 - USB Device Firmware Update (DFU) class support:
1322 CONFIG_USB_FUNCTION_DFU
1323 This enables the USB portion of the DFU USB class
1326 This enables the command "dfu" which is used to have
1327 U-Boot create a DFU class device via USB. This command
1328 requires that the "dfu_alt_info" environment variable be
1329 set and define the alt settings to expose to the host.
1332 This enables support for exposing (e)MMC devices via DFU.
1335 This enables support for exposing NAND devices via DFU.
1338 This enables support for exposing RAM via DFU.
1339 Note: DFU spec refer to non-volatile memory usage, but
1340 allow usages beyond the scope of spec - here RAM usage,
1341 one that would help mostly the developer.
1343 CONFIG_SYS_DFU_DATA_BUF_SIZE
1344 Dfu transfer uses a buffer before writing data to the
1345 raw storage device. Make the size (in bytes) of this buffer
1346 configurable. The size of this buffer is also configurable
1347 through the "dfu_bufsiz" environment variable.
1349 CONFIG_SYS_DFU_MAX_FILE_SIZE
1350 When updating files rather than the raw storage device,
1351 we use a static buffer to copy the file into and then write
1352 the buffer once we've been given the whole file. Define
1353 this to the maximum filesize (in bytes) for the buffer.
1354 Default is 4 MiB if undefined.
1356 DFU_DEFAULT_POLL_TIMEOUT
1357 Poll timeout [ms], is the timeout a device can send to the
1358 host. The host must wait for this timeout before sending
1359 a subsequent DFU_GET_STATUS request to the device.
1361 DFU_MANIFEST_POLL_TIMEOUT
1362 Poll timeout [ms], which the device sends to the host when
1363 entering dfuMANIFEST state. Host waits this timeout, before
1364 sending again an USB request to the device.
1366 - USB Device Android Fastboot support:
1367 CONFIG_USB_FUNCTION_FASTBOOT
1368 This enables the USB part of the fastboot gadget
1371 This enables the command "fastboot" which enables the Android
1372 fastboot mode for the platform's USB device. Fastboot is a USB
1373 protocol for downloading images, flashing and device control
1374 used on Android devices.
1375 See doc/README.android-fastboot for more information.
1377 CONFIG_ANDROID_BOOT_IMAGE
1378 This enables support for booting images which use the Android
1379 image format header.
1381 CONFIG_FASTBOOT_BUF_ADDR
1382 The fastboot protocol requires a large memory buffer for
1383 downloads. Define this to the starting RAM address to use for
1386 CONFIG_FASTBOOT_BUF_SIZE
1387 The fastboot protocol requires a large memory buffer for
1388 downloads. This buffer should be as large as possible for a
1389 platform. Define this to the size available RAM for fastboot.
1391 CONFIG_FASTBOOT_FLASH
1392 The fastboot protocol includes a "flash" command for writing
1393 the downloaded image to a non-volatile storage device. Define
1394 this to enable the "fastboot flash" command.
1396 CONFIG_FASTBOOT_FLASH_MMC_DEV
1397 The fastboot "flash" command requires additional information
1398 regarding the non-volatile storage device. Define this to
1399 the eMMC device that fastboot should use to store the image.
1401 CONFIG_FASTBOOT_GPT_NAME
1402 The fastboot "flash" command supports writing the downloaded
1403 image to the Protective MBR and the Primary GUID Partition
1404 Table. (Additionally, this downloaded image is post-processed
1405 to generate and write the Backup GUID Partition Table.)
1406 This occurs when the specified "partition name" on the
1407 "fastboot flash" command line matches this value.
1408 The default is "gpt" if undefined.
1410 CONFIG_FASTBOOT_MBR_NAME
1411 The fastboot "flash" command supports writing the downloaded
1413 This occurs when the "partition name" specified on the
1414 "fastboot flash" command line matches this value.
1415 If not defined the default value "mbr" is used.
1417 - Journaling Flash filesystem support:
1419 Define these for a default partition on a NAND device
1421 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1422 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1423 Define these for a default partition on a NOR device
1426 See Kconfig help for available keyboard drivers.
1430 Define this to enable a custom keyboard support.
1431 This simply calls drv_keyboard_init() which must be
1432 defined in your board-specific files. This option is deprecated
1433 and is only used by novena. For new boards, use driver model
1438 Enable the Freescale DIU video driver. Reference boards for
1439 SOCs that have a DIU should define this macro to enable DIU
1440 support, and should also define these other macros:
1445 CONFIG_VIDEO_SW_CURSOR
1446 CONFIG_VGA_AS_SINGLE_DEVICE
1448 CONFIG_VIDEO_BMP_LOGO
1450 The DIU driver will look for the 'video-mode' environment
1451 variable, and if defined, enable the DIU as a console during
1452 boot. See the documentation file doc/README.video for a
1453 description of this variable.
1455 - LCD Support: CONFIG_LCD
1457 Define this to enable LCD support (for output to LCD
1458 display); also select one of the supported displays
1459 by defining one of these:
1463 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1465 CONFIG_NEC_NL6448AC33:
1467 NEC NL6448AC33-18. Active, color, single scan.
1469 CONFIG_NEC_NL6448BC20
1471 NEC NL6448BC20-08. 6.5", 640x480.
1472 Active, color, single scan.
1474 CONFIG_NEC_NL6448BC33_54
1476 NEC NL6448BC33-54. 10.4", 640x480.
1477 Active, color, single scan.
1481 Sharp 320x240. Active, color, single scan.
1482 It isn't 16x9, and I am not sure what it is.
1484 CONFIG_SHARP_LQ64D341
1486 Sharp LQ64D341 display, 640x480.
1487 Active, color, single scan.
1491 HLD1045 display, 640x480.
1492 Active, color, single scan.
1496 Optrex CBL50840-2 NF-FW 99 22 M5
1498 Hitachi LMG6912RPFC-00T
1502 320x240. Black & white.
1504 CONFIG_LCD_ALIGNMENT
1506 Normally the LCD is page-aligned (typically 4KB). If this is
1507 defined then the LCD will be aligned to this value instead.
1508 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1509 here, since it is cheaper to change data cache settings on
1510 a per-section basis.
1515 Sometimes, for example if the display is mounted in portrait
1516 mode or even if it's mounted landscape but rotated by 180degree,
1517 we need to rotate our content of the display relative to the
1518 framebuffer, so that user can read the messages which are
1520 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1521 initialized with a given rotation from "vl_rot" out of
1522 "vidinfo_t" which is provided by the board specific code.
1523 The value for vl_rot is coded as following (matching to
1524 fbcon=rotate:<n> linux-kernel commandline):
1525 0 = no rotation respectively 0 degree
1526 1 = 90 degree rotation
1527 2 = 180 degree rotation
1528 3 = 270 degree rotation
1530 If CONFIG_LCD_ROTATION is not defined, the console will be
1531 initialized with 0degree rotation.
1535 Support drawing of RLE8-compressed bitmaps on the LCD.
1539 Enables an 'i2c edid' command which can read EDID
1540 information over I2C from an attached LCD display.
1542 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1544 If this option is set, the environment is checked for
1545 a variable "splashimage". If found, the usual display
1546 of logo, copyright and system information on the LCD
1547 is suppressed and the BMP image at the address
1548 specified in "splashimage" is loaded instead. The
1549 console is redirected to the "nulldev", too. This
1550 allows for a "silent" boot where a splash screen is
1551 loaded very quickly after power-on.
1553 CONFIG_SPLASHIMAGE_GUARD
1555 If this option is set, then U-Boot will prevent the environment
1556 variable "splashimage" from being set to a problematic address
1557 (see doc/README.displaying-bmps).
1558 This option is useful for targets where, due to alignment
1559 restrictions, an improperly aligned BMP image will cause a data
1560 abort. If you think you will not have problems with unaligned
1561 accesses (for example because your toolchain prevents them)
1562 there is no need to set this option.
1564 CONFIG_SPLASH_SCREEN_ALIGN
1566 If this option is set the splash image can be freely positioned
1567 on the screen. Environment variable "splashpos" specifies the
1568 position as "x,y". If a positive number is given it is used as
1569 number of pixel from left/top. If a negative number is given it
1570 is used as number of pixel from right/bottom. You can also
1571 specify 'm' for centering the image.
1574 setenv splashpos m,m
1575 => image at center of screen
1577 setenv splashpos 30,20
1578 => image at x = 30 and y = 20
1580 setenv splashpos -10,m
1581 => vertically centered image
1582 at x = dspWidth - bmpWidth - 9
1584 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1586 If this option is set, additionally to standard BMP
1587 images, gzipped BMP images can be displayed via the
1588 splashscreen support or the bmp command.
1590 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1592 If this option is set, 8-bit RLE compressed BMP images
1593 can be displayed via the splashscreen support or the
1596 - Compression support:
1599 Enabled by default to support gzip compressed images.
1603 If this option is set, support for bzip2 compressed
1604 images is included. If not, only uncompressed and gzip
1605 compressed images are supported.
1607 NOTE: the bzip2 algorithm requires a lot of RAM, so
1608 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1614 The address of PHY on MII bus.
1616 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1618 The clock frequency of the MII bus
1620 CONFIG_PHY_RESET_DELAY
1622 Some PHY like Intel LXT971A need extra delay after
1623 reset before any MII register access is possible.
1624 For such PHY, set this option to the usec delay
1625 required. (minimum 300usec for LXT971A)
1627 CONFIG_PHY_CMD_DELAY (ppc4xx)
1629 Some PHY like Intel LXT971A need extra delay after
1630 command issued before MII status register can be read
1635 Define a default value for the IP address to use for
1636 the default Ethernet interface, in case this is not
1637 determined through e.g. bootp.
1638 (Environment variable "ipaddr")
1640 - Server IP address:
1643 Defines a default value for the IP address of a TFTP
1644 server to contact when using the "tftboot" command.
1645 (Environment variable "serverip")
1647 CONFIG_KEEP_SERVERADDR
1649 Keeps the server's MAC address, in the env 'serveraddr'
1650 for passing to bootargs (like Linux's netconsole option)
1652 - Gateway IP address:
1655 Defines a default value for the IP address of the
1656 default router where packets to other networks are
1658 (Environment variable "gatewayip")
1663 Defines a default value for the subnet mask (or
1664 routing prefix) which is used to determine if an IP
1665 address belongs to the local subnet or needs to be
1666 forwarded through a router.
1667 (Environment variable "netmask")
1669 - Multicast TFTP Mode:
1672 Defines whether you want to support multicast TFTP as per
1673 rfc-2090; for example to work with atftp. Lets lots of targets
1674 tftp down the same boot image concurrently. Note: the Ethernet
1675 driver in use must provide a function: mcast() to join/leave a
1678 - BOOTP Recovery Mode:
1679 CONFIG_BOOTP_RANDOM_DELAY
1681 If you have many targets in a network that try to
1682 boot using BOOTP, you may want to avoid that all
1683 systems send out BOOTP requests at precisely the same
1684 moment (which would happen for instance at recovery
1685 from a power failure, when all systems will try to
1686 boot, thus flooding the BOOTP server. Defining
1687 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1688 inserted before sending out BOOTP requests. The
1689 following delays are inserted then:
1691 1st BOOTP request: delay 0 ... 1 sec
1692 2nd BOOTP request: delay 0 ... 2 sec
1693 3rd BOOTP request: delay 0 ... 4 sec
1695 BOOTP requests: delay 0 ... 8 sec
1697 CONFIG_BOOTP_ID_CACHE_SIZE
1699 BOOTP packets are uniquely identified using a 32-bit ID. The
1700 server will copy the ID from client requests to responses and
1701 U-Boot will use this to determine if it is the destination of
1702 an incoming response. Some servers will check that addresses
1703 aren't in use before handing them out (usually using an ARP
1704 ping) and therefore take up to a few hundred milliseconds to
1705 respond. Network congestion may also influence the time it
1706 takes for a response to make it back to the client. If that
1707 time is too long, U-Boot will retransmit requests. In order
1708 to allow earlier responses to still be accepted after these
1709 retransmissions, U-Boot's BOOTP client keeps a small cache of
1710 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1711 cache. The default is to keep IDs for up to four outstanding
1712 requests. Increasing this will allow U-Boot to accept offers
1713 from a BOOTP client in networks with unusually high latency.
1715 - DHCP Advanced Options:
1716 You can fine tune the DHCP functionality by defining
1717 CONFIG_BOOTP_* symbols:
1719 CONFIG_BOOTP_SUBNETMASK
1720 CONFIG_BOOTP_GATEWAY
1721 CONFIG_BOOTP_HOSTNAME
1722 CONFIG_BOOTP_NISDOMAIN
1723 CONFIG_BOOTP_BOOTPATH
1724 CONFIG_BOOTP_BOOTFILESIZE
1727 CONFIG_BOOTP_SEND_HOSTNAME
1728 CONFIG_BOOTP_NTPSERVER
1729 CONFIG_BOOTP_TIMEOFFSET
1730 CONFIG_BOOTP_VENDOREX
1731 CONFIG_BOOTP_MAY_FAIL
1733 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1734 environment variable, not the BOOTP server.
1736 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1737 after the configured retry count, the call will fail
1738 instead of starting over. This can be used to fail over
1739 to Link-local IP address configuration if the DHCP server
1742 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1743 serverip from a DHCP server, it is possible that more
1744 than one DNS serverip is offered to the client.
1745 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1746 serverip will be stored in the additional environment
1747 variable "dnsip2". The first DNS serverip is always
1748 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1751 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1752 to do a dynamic update of a DNS server. To do this, they
1753 need the hostname of the DHCP requester.
1754 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1755 of the "hostname" environment variable is passed as
1756 option 12 to the DHCP server.
1758 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1760 A 32bit value in microseconds for a delay between
1761 receiving a "DHCP Offer" and sending the "DHCP Request".
1762 This fixes a problem with certain DHCP servers that don't
1763 respond 100% of the time to a "DHCP request". E.g. On an
1764 AT91RM9200 processor running at 180MHz, this delay needed
1765 to be *at least* 15,000 usec before a Windows Server 2003
1766 DHCP server would reply 100% of the time. I recommend at
1767 least 50,000 usec to be safe. The alternative is to hope
1768 that one of the retries will be successful but note that
1769 the DHCP timeout and retry process takes a longer than
1772 - Link-local IP address negotiation:
1773 Negotiate with other link-local clients on the local network
1774 for an address that doesn't require explicit configuration.
1775 This is especially useful if a DHCP server cannot be guaranteed
1776 to exist in all environments that the device must operate.
1778 See doc/README.link-local for more information.
1781 CONFIG_CDP_DEVICE_ID
1783 The device id used in CDP trigger frames.
1785 CONFIG_CDP_DEVICE_ID_PREFIX
1787 A two character string which is prefixed to the MAC address
1792 A printf format string which contains the ascii name of
1793 the port. Normally is set to "eth%d" which sets
1794 eth0 for the first Ethernet, eth1 for the second etc.
1796 CONFIG_CDP_CAPABILITIES
1798 A 32bit integer which indicates the device capabilities;
1799 0x00000010 for a normal host which does not forwards.
1803 An ascii string containing the version of the software.
1807 An ascii string containing the name of the platform.
1811 A 32bit integer sent on the trigger.
1813 CONFIG_CDP_POWER_CONSUMPTION
1815 A 16bit integer containing the power consumption of the
1816 device in .1 of milliwatts.
1818 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1820 A byte containing the id of the VLAN.
1822 - Status LED: CONFIG_LED_STATUS
1824 Several configurations allow to display the current
1825 status using a LED. For instance, the LED will blink
1826 fast while running U-Boot code, stop blinking as
1827 soon as a reply to a BOOTP request was received, and
1828 start blinking slow once the Linux kernel is running
1829 (supported by a status LED driver in the Linux
1830 kernel). Defining CONFIG_LED_STATUS enables this
1835 CONFIG_LED_STATUS_GPIO
1836 The status LED can be connected to a GPIO pin.
1837 In such cases, the gpio_led driver can be used as a
1838 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1839 to include the gpio_led driver in the U-Boot binary.
1841 CONFIG_GPIO_LED_INVERTED_TABLE
1842 Some GPIO connected LEDs may have inverted polarity in which
1843 case the GPIO high value corresponds to LED off state and
1844 GPIO low value corresponds to LED on state.
1845 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1846 with a list of GPIO LEDs that have inverted polarity.
1848 - I2C Support: CONFIG_SYS_I2C
1850 This enable the NEW i2c subsystem, and will allow you to use
1851 i2c commands at the u-boot command line (as long as you set
1852 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1853 based realtime clock chips or other i2c devices. See
1854 common/cmd_i2c.c for a description of the command line
1857 ported i2c driver to the new framework:
1858 - drivers/i2c/soft_i2c.c:
1859 - activate first bus with CONFIG_SYS_I2C_SOFT define
1860 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1861 for defining speed and slave address
1862 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1863 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1864 for defining speed and slave address
1865 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1866 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1867 for defining speed and slave address
1868 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1869 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1870 for defining speed and slave address
1872 - drivers/i2c/fsl_i2c.c:
1873 - activate i2c driver with CONFIG_SYS_I2C_FSL
1874 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1875 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1876 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1878 - If your board supports a second fsl i2c bus, define
1879 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1880 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1881 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1884 - drivers/i2c/tegra_i2c.c:
1885 - activate this driver with CONFIG_SYS_I2C_TEGRA
1886 - This driver adds 4 i2c buses with a fix speed from
1887 100000 and the slave addr 0!
1889 - drivers/i2c/ppc4xx_i2c.c
1890 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1891 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1892 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1894 - drivers/i2c/i2c_mxc.c
1895 - activate this driver with CONFIG_SYS_I2C_MXC
1896 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1897 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1898 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1899 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1900 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1901 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1902 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1903 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1904 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1905 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1906 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1907 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1908 If those defines are not set, default value is 100000
1909 for speed, and 0 for slave.
1911 - drivers/i2c/rcar_i2c.c:
1912 - activate this driver with CONFIG_SYS_I2C_RCAR
1913 - This driver adds 4 i2c buses
1915 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1916 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1917 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1918 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1919 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1920 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1921 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1922 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1923 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1925 - drivers/i2c/sh_i2c.c:
1926 - activate this driver with CONFIG_SYS_I2C_SH
1927 - This driver adds from 2 to 5 i2c buses
1929 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1930 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1931 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1932 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1933 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1934 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1935 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1936 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1937 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1938 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1939 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1941 - drivers/i2c/omap24xx_i2c.c
1942 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1943 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1944 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1945 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1946 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1947 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1948 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1949 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1950 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1951 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1952 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1954 - drivers/i2c/zynq_i2c.c
1955 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1956 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1957 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1959 - drivers/i2c/s3c24x0_i2c.c:
1960 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1961 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1962 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1963 with a fix speed from 100000 and the slave addr 0!
1965 - drivers/i2c/ihs_i2c.c
1966 - activate this driver with CONFIG_SYS_I2C_IHS
1967 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1968 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1969 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1970 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1971 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1972 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1973 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1974 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1975 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1976 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1977 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1978 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1979 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1980 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1981 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1982 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1983 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1984 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1985 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1986 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1987 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1991 CONFIG_SYS_NUM_I2C_BUSES
1992 Hold the number of i2c buses you want to use.
1994 CONFIG_SYS_I2C_DIRECT_BUS
1995 define this, if you don't use i2c muxes on your hardware.
1996 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1999 CONFIG_SYS_I2C_MAX_HOPS
2000 define how many muxes are maximal consecutively connected
2001 on one i2c bus. If you not use i2c muxes, omit this
2004 CONFIG_SYS_I2C_BUSES
2005 hold a list of buses you want to use, only used if
2006 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2007 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2008 CONFIG_SYS_NUM_I2C_BUSES = 9:
2010 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2011 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2012 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2013 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2014 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2015 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2016 {1, {I2C_NULL_HOP}}, \
2017 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2018 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2022 bus 0 on adapter 0 without a mux
2023 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2024 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2025 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2026 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2027 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2028 bus 6 on adapter 1 without a mux
2029 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2030 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2032 If you do not have i2c muxes on your board, omit this define.
2034 - Legacy I2C Support:
2035 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2036 then the following macros need to be defined (examples are
2037 from include/configs/lwmon.h):
2041 (Optional). Any commands necessary to enable the I2C
2042 controller or configure ports.
2044 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2048 The code necessary to make the I2C data line active
2049 (driven). If the data line is open collector, this
2052 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2056 The code necessary to make the I2C data line tri-stated
2057 (inactive). If the data line is open collector, this
2060 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2064 Code that returns true if the I2C data line is high,
2067 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2071 If <bit> is true, sets the I2C data line high. If it
2072 is false, it clears it (low).
2074 eg: #define I2C_SDA(bit) \
2075 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2076 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2080 If <bit> is true, sets the I2C clock line high. If it
2081 is false, it clears it (low).
2083 eg: #define I2C_SCL(bit) \
2084 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2085 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2089 This delay is invoked four times per clock cycle so this
2090 controls the rate of data transfer. The data rate thus
2091 is 1 / (I2C_DELAY * 4). Often defined to be something
2094 #define I2C_DELAY udelay(2)
2096 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2098 If your arch supports the generic GPIO framework (asm/gpio.h),
2099 then you may alternatively define the two GPIOs that are to be
2100 used as SCL / SDA. Any of the previous I2C_xxx macros will
2101 have GPIO-based defaults assigned to them as appropriate.
2103 You should define these to the GPIO value as given directly to
2104 the generic GPIO functions.
2106 CONFIG_SYS_I2C_INIT_BOARD
2108 When a board is reset during an i2c bus transfer
2109 chips might think that the current transfer is still
2110 in progress. On some boards it is possible to access
2111 the i2c SCLK line directly, either by using the
2112 processor pin as a GPIO or by having a second pin
2113 connected to the bus. If this option is defined a
2114 custom i2c_init_board() routine in boards/xxx/board.c
2115 is run early in the boot sequence.
2117 CONFIG_I2C_MULTI_BUS
2119 This option allows the use of multiple I2C buses, each of which
2120 must have a controller. At any point in time, only one bus is
2121 active. To switch to a different bus, use the 'i2c dev' command.
2122 Note that bus numbering is zero-based.
2124 CONFIG_SYS_I2C_NOPROBES
2126 This option specifies a list of I2C devices that will be skipped
2127 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2128 is set, specify a list of bus-device pairs. Otherwise, specify
2129 a 1D array of device addresses
2132 #undef CONFIG_I2C_MULTI_BUS
2133 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2135 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2137 #define CONFIG_I2C_MULTI_BUS
2138 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2140 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2142 CONFIG_SYS_SPD_BUS_NUM
2144 If defined, then this indicates the I2C bus number for DDR SPD.
2145 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2147 CONFIG_SYS_RTC_BUS_NUM
2149 If defined, then this indicates the I2C bus number for the RTC.
2150 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2152 CONFIG_SOFT_I2C_READ_REPEATED_START
2154 defining this will force the i2c_read() function in
2155 the soft_i2c driver to perform an I2C repeated start
2156 between writing the address pointer and reading the
2157 data. If this define is omitted the default behaviour
2158 of doing a stop-start sequence will be used. Most I2C
2159 devices can use either method, but some require one or
2162 - SPI Support: CONFIG_SPI
2164 Enables SPI driver (so far only tested with
2165 SPI EEPROM, also an instance works with Crystal A/D and
2166 D/As on the SACSng board)
2170 Enables the driver for SPI controller on SuperH. Currently
2171 only SH7757 is supported.
2175 Enables a software (bit-bang) SPI driver rather than
2176 using hardware support. This is a general purpose
2177 driver that only requires three general I/O port pins
2178 (two outputs, one input) to function. If this is
2179 defined, the board configuration must define several
2180 SPI configuration items (port pins to use, etc). For
2181 an example, see include/configs/sacsng.h.
2185 Enables a hardware SPI driver for general-purpose reads
2186 and writes. As with CONFIG_SOFT_SPI, the board configuration
2187 must define a list of chip-select function pointers.
2188 Currently supported on some MPC8xxx processors. For an
2189 example, see include/configs/mpc8349emds.h.
2193 Enables the driver for the SPI controllers on i.MX and MXC
2194 SoCs. Currently i.MX31/35/51 are supported.
2196 CONFIG_SYS_SPI_MXC_WAIT
2197 Timeout for waiting until spi transfer completed.
2198 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2200 - FPGA Support: CONFIG_FPGA
2202 Enables FPGA subsystem.
2204 CONFIG_FPGA_<vendor>
2206 Enables support for specific chip vendors.
2209 CONFIG_FPGA_<family>
2211 Enables support for FPGA family.
2212 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2216 Specify the number of FPGA devices to support.
2218 CONFIG_SYS_FPGA_PROG_FEEDBACK
2220 Enable printing of hash marks during FPGA configuration.
2222 CONFIG_SYS_FPGA_CHECK_BUSY
2224 Enable checks on FPGA configuration interface busy
2225 status by the configuration function. This option
2226 will require a board or device specific function to
2231 If defined, a function that provides delays in the FPGA
2232 configuration driver.
2234 CONFIG_SYS_FPGA_CHECK_CTRLC
2235 Allow Control-C to interrupt FPGA configuration
2237 CONFIG_SYS_FPGA_CHECK_ERROR
2239 Check for configuration errors during FPGA bitfile
2240 loading. For example, abort during Virtex II
2241 configuration if the INIT_B line goes low (which
2242 indicated a CRC error).
2244 CONFIG_SYS_FPGA_WAIT_INIT
2246 Maximum time to wait for the INIT_B line to de-assert
2247 after PROB_B has been de-asserted during a Virtex II
2248 FPGA configuration sequence. The default time is 500
2251 CONFIG_SYS_FPGA_WAIT_BUSY
2253 Maximum time to wait for BUSY to de-assert during
2254 Virtex II FPGA configuration. The default is 5 ms.
2256 CONFIG_SYS_FPGA_WAIT_CONFIG
2258 Time to wait after FPGA configuration. The default is
2261 - Configuration Management:
2264 Some SoCs need special image types (e.g. U-Boot binary
2265 with a special header) as build targets. By defining
2266 CONFIG_BUILD_TARGET in the SoC / board header, this
2267 special image will be automatically built upon calling
2272 If defined, this string will be added to the U-Boot
2273 version information (U_BOOT_VERSION)
2275 - Vendor Parameter Protection:
2277 U-Boot considers the values of the environment
2278 variables "serial#" (Board Serial Number) and
2279 "ethaddr" (Ethernet Address) to be parameters that
2280 are set once by the board vendor / manufacturer, and
2281 protects these variables from casual modification by
2282 the user. Once set, these variables are read-only,
2283 and write or delete attempts are rejected. You can
2284 change this behaviour:
2286 If CONFIG_ENV_OVERWRITE is #defined in your config
2287 file, the write protection for vendor parameters is
2288 completely disabled. Anybody can change or delete
2291 Alternatively, if you define _both_ an ethaddr in the
2292 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2293 Ethernet address is installed in the environment,
2294 which can be changed exactly ONCE by the user. [The
2295 serial# is unaffected by this, i. e. it remains
2298 The same can be accomplished in a more flexible way
2299 for any variable by configuring the type of access
2300 to allow for those variables in the ".flags" variable
2301 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2306 Define this variable to enable the reservation of
2307 "protected RAM", i. e. RAM which is not overwritten
2308 by U-Boot. Define CONFIG_PRAM to hold the number of
2309 kB you want to reserve for pRAM. You can overwrite
2310 this default value by defining an environment
2311 variable "pram" to the number of kB you want to
2312 reserve. Note that the board info structure will
2313 still show the full amount of RAM. If pRAM is
2314 reserved, a new environment variable "mem" will
2315 automatically be defined to hold the amount of
2316 remaining RAM in a form that can be passed as boot
2317 argument to Linux, for instance like that:
2319 setenv bootargs ... mem=\${mem}
2322 This way you can tell Linux not to use this memory,
2323 either, which results in a memory region that will
2324 not be affected by reboots.
2326 *WARNING* If your board configuration uses automatic
2327 detection of the RAM size, you must make sure that
2328 this memory test is non-destructive. So far, the
2329 following board configurations are known to be
2332 IVMS8, IVML24, SPD8xx,
2333 HERMES, IP860, RPXlite, LWMON,
2336 - Access to physical memory region (> 4GB)
2337 Some basic support is provided for operations on memory not
2338 normally accessible to U-Boot - e.g. some architectures
2339 support access to more than 4GB of memory on 32-bit
2340 machines using physical address extension or similar.
2341 Define CONFIG_PHYSMEM to access this basic support, which
2342 currently only supports clearing the memory.
2347 Define this variable to stop the system in case of a
2348 fatal error, so that you have to reset it manually.
2349 This is probably NOT a good idea for an embedded
2350 system where you want the system to reboot
2351 automatically as fast as possible, but it may be
2352 useful during development since you can try to debug
2353 the conditions that lead to the situation.
2355 CONFIG_NET_RETRY_COUNT
2357 This variable defines the number of retries for
2358 network operations like ARP, RARP, TFTP, or BOOTP
2359 before giving up the operation. If not defined, a
2360 default value of 5 is used.
2364 Timeout waiting for an ARP reply in milliseconds.
2368 Timeout in milliseconds used in NFS protocol.
2369 If you encounter "ERROR: Cannot umount" in nfs command,
2370 try longer timeout such as
2371 #define CONFIG_NFS_TIMEOUT 10000UL
2373 - Command Interpreter:
2374 CONFIG_AUTO_COMPLETE
2376 Enable auto completion of commands using TAB.
2378 CONFIG_SYS_PROMPT_HUSH_PS2
2380 This defines the secondary prompt string, which is
2381 printed when the command interpreter needs more input
2382 to complete a command. Usually "> ".
2386 In the current implementation, the local variables
2387 space and global environment variables space are
2388 separated. Local variables are those you define by
2389 simply typing `name=value'. To access a local
2390 variable later on, you have write `$name' or
2391 `${name}'; to execute the contents of a variable
2392 directly type `$name' at the command prompt.
2394 Global environment variables are those you use
2395 setenv/printenv to work with. To run a command stored
2396 in such a variable, you need to use the run command,
2397 and you must not use the '$' sign to access them.
2399 To store commands and special characters in a
2400 variable, please use double quotation marks
2401 surrounding the whole text of the variable, instead
2402 of the backslashes before semicolons and special
2405 - Command Line Editing and History:
2406 CONFIG_CMDLINE_EDITING
2408 Enable editing and History functions for interactive
2409 command line input operations
2411 - Command Line PS1/PS2 support:
2412 CONFIG_CMDLINE_PS_SUPPORT
2414 Enable support for changing the command prompt string
2415 at run-time. Only static string is supported so far.
2416 The string is obtained from environment variables PS1
2419 - Default Environment:
2420 CONFIG_EXTRA_ENV_SETTINGS
2422 Define this to contain any number of null terminated
2423 strings (variable = value pairs) that will be part of
2424 the default environment compiled into the boot image.
2426 For example, place something like this in your
2427 board's config file:
2429 #define CONFIG_EXTRA_ENV_SETTINGS \
2433 Warning: This method is based on knowledge about the
2434 internal format how the environment is stored by the
2435 U-Boot code. This is NOT an official, exported
2436 interface! Although it is unlikely that this format
2437 will change soon, there is no guarantee either.
2438 You better know what you are doing here.
2440 Note: overly (ab)use of the default environment is
2441 discouraged. Make sure to check other ways to preset
2442 the environment like the "source" command or the
2445 CONFIG_ENV_VARS_UBOOT_CONFIG
2447 Define this in order to add variables describing the
2448 U-Boot build configuration to the default environment.
2449 These will be named arch, cpu, board, vendor, and soc.
2451 Enabling this option will cause the following to be defined:
2459 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2461 Define this in order to add variables describing certain
2462 run-time determined information about the hardware to the
2463 environment. These will be named board_name, board_rev.
2465 CONFIG_DELAY_ENVIRONMENT
2467 Normally the environment is loaded when the board is
2468 initialised so that it is available to U-Boot. This inhibits
2469 that so that the environment is not available until
2470 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2471 this is instead controlled by the value of
2472 /config/load-environment.
2474 - DataFlash Support:
2475 CONFIG_HAS_DATAFLASH
2477 Defining this option enables DataFlash features and
2478 allows to read/write in Dataflash via the standard
2481 - Serial Flash support
2484 Defining this option enables SPI flash commands
2485 'sf probe/read/write/erase/update'.
2487 Usage requires an initial 'probe' to define the serial
2488 flash parameters, followed by read/write/erase/update
2491 The following defaults may be provided by the platform
2492 to handle the common case when only a single serial
2493 flash is present on the system.
2495 CONFIG_SF_DEFAULT_BUS Bus identifier
2496 CONFIG_SF_DEFAULT_CS Chip-select
2497 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2498 CONFIG_SF_DEFAULT_SPEED in Hz
2502 Define this option to include a destructive SPI flash
2505 - SystemACE Support:
2508 Adding this option adds support for Xilinx SystemACE
2509 chips attached via some sort of local bus. The address
2510 of the chip must also be defined in the
2511 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2513 #define CONFIG_SYSTEMACE
2514 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2516 When SystemACE support is added, the "ace" device type
2517 becomes available to the fat commands, i.e. fatls.
2519 - TFTP Fixed UDP Port:
2522 If this is defined, the environment variable tftpsrcp
2523 is used to supply the TFTP UDP source port value.
2524 If tftpsrcp isn't defined, the normal pseudo-random port
2525 number generator is used.
2527 Also, the environment variable tftpdstp is used to supply
2528 the TFTP UDP destination port value. If tftpdstp isn't
2529 defined, the normal port 69 is used.
2531 The purpose for tftpsrcp is to allow a TFTP server to
2532 blindly start the TFTP transfer using the pre-configured
2533 target IP address and UDP port. This has the effect of
2534 "punching through" the (Windows XP) firewall, allowing
2535 the remainder of the TFTP transfer to proceed normally.
2536 A better solution is to properly configure the firewall,
2537 but sometimes that is not allowed.
2539 - bootcount support:
2540 CONFIG_BOOTCOUNT_LIMIT
2542 This enables the bootcounter support, see:
2543 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2546 enable special bootcounter support on at91sam9xe based boards.
2548 enable special bootcounter support on da850 based boards.
2549 CONFIG_BOOTCOUNT_RAM
2550 enable support for the bootcounter in RAM
2551 CONFIG_BOOTCOUNT_I2C
2552 enable support for the bootcounter on an i2c (like RTC) device.
2553 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2554 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2556 CONFIG_BOOTCOUNT_ALEN = address len
2558 - Show boot progress:
2559 CONFIG_SHOW_BOOT_PROGRESS
2561 Defining this option allows to add some board-
2562 specific code (calling a user-provided function
2563 "show_boot_progress(int)") that enables you to show
2564 the system's boot progress on some display (for
2565 example, some LED's) on your board. At the moment,
2566 the following checkpoints are implemented:
2569 Legacy uImage format:
2572 1 common/cmd_bootm.c before attempting to boot an image
2573 -1 common/cmd_bootm.c Image header has bad magic number
2574 2 common/cmd_bootm.c Image header has correct magic number
2575 -2 common/cmd_bootm.c Image header has bad checksum
2576 3 common/cmd_bootm.c Image header has correct checksum
2577 -3 common/cmd_bootm.c Image data has bad checksum
2578 4 common/cmd_bootm.c Image data has correct checksum
2579 -4 common/cmd_bootm.c Image is for unsupported architecture
2580 5 common/cmd_bootm.c Architecture check OK
2581 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2582 6 common/cmd_bootm.c Image Type check OK
2583 -6 common/cmd_bootm.c gunzip uncompression error
2584 -7 common/cmd_bootm.c Unimplemented compression type
2585 7 common/cmd_bootm.c Uncompression OK
2586 8 common/cmd_bootm.c No uncompress/copy overwrite error
2587 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2589 9 common/image.c Start initial ramdisk verification
2590 -10 common/image.c Ramdisk header has bad magic number
2591 -11 common/image.c Ramdisk header has bad checksum
2592 10 common/image.c Ramdisk header is OK
2593 -12 common/image.c Ramdisk data has bad checksum
2594 11 common/image.c Ramdisk data has correct checksum
2595 12 common/image.c Ramdisk verification complete, start loading
2596 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2597 13 common/image.c Start multifile image verification
2598 14 common/image.c No initial ramdisk, no multifile, continue.
2600 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2602 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2603 -31 post/post.c POST test failed, detected by post_output_backlog()
2604 -32 post/post.c POST test failed, detected by post_run_single()
2606 34 common/cmd_doc.c before loading a Image from a DOC device
2607 -35 common/cmd_doc.c Bad usage of "doc" command
2608 35 common/cmd_doc.c correct usage of "doc" command
2609 -36 common/cmd_doc.c No boot device
2610 36 common/cmd_doc.c correct boot device
2611 -37 common/cmd_doc.c Unknown Chip ID on boot device
2612 37 common/cmd_doc.c correct chip ID found, device available
2613 -38 common/cmd_doc.c Read Error on boot device
2614 38 common/cmd_doc.c reading Image header from DOC device OK
2615 -39 common/cmd_doc.c Image header has bad magic number
2616 39 common/cmd_doc.c Image header has correct magic number
2617 -40 common/cmd_doc.c Error reading Image from DOC device
2618 40 common/cmd_doc.c Image header has correct magic number
2619 41 common/cmd_ide.c before loading a Image from a IDE device
2620 -42 common/cmd_ide.c Bad usage of "ide" command
2621 42 common/cmd_ide.c correct usage of "ide" command
2622 -43 common/cmd_ide.c No boot device
2623 43 common/cmd_ide.c boot device found
2624 -44 common/cmd_ide.c Device not available
2625 44 common/cmd_ide.c Device available
2626 -45 common/cmd_ide.c wrong partition selected
2627 45 common/cmd_ide.c partition selected
2628 -46 common/cmd_ide.c Unknown partition table
2629 46 common/cmd_ide.c valid partition table found
2630 -47 common/cmd_ide.c Invalid partition type
2631 47 common/cmd_ide.c correct partition type
2632 -48 common/cmd_ide.c Error reading Image Header on boot device
2633 48 common/cmd_ide.c reading Image Header from IDE device OK
2634 -49 common/cmd_ide.c Image header has bad magic number
2635 49 common/cmd_ide.c Image header has correct magic number
2636 -50 common/cmd_ide.c Image header has bad checksum
2637 50 common/cmd_ide.c Image header has correct checksum
2638 -51 common/cmd_ide.c Error reading Image from IDE device
2639 51 common/cmd_ide.c reading Image from IDE device OK
2640 52 common/cmd_nand.c before loading a Image from a NAND device
2641 -53 common/cmd_nand.c Bad usage of "nand" command
2642 53 common/cmd_nand.c correct usage of "nand" command
2643 -54 common/cmd_nand.c No boot device
2644 54 common/cmd_nand.c boot device found
2645 -55 common/cmd_nand.c Unknown Chip ID on boot device
2646 55 common/cmd_nand.c correct chip ID found, device available
2647 -56 common/cmd_nand.c Error reading Image Header on boot device
2648 56 common/cmd_nand.c reading Image Header from NAND device OK
2649 -57 common/cmd_nand.c Image header has bad magic number
2650 57 common/cmd_nand.c Image header has correct magic number
2651 -58 common/cmd_nand.c Error reading Image from NAND device
2652 58 common/cmd_nand.c reading Image from NAND device OK
2654 -60 common/env_common.c Environment has a bad CRC, using default
2656 64 net/eth.c starting with Ethernet configuration.
2657 -64 net/eth.c no Ethernet found.
2658 65 net/eth.c Ethernet found.
2660 -80 common/cmd_net.c usage wrong
2661 80 common/cmd_net.c before calling net_loop()
2662 -81 common/cmd_net.c some error in net_loop() occurred
2663 81 common/cmd_net.c net_loop() back without error
2664 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2665 82 common/cmd_net.c trying automatic boot
2666 83 common/cmd_net.c running "source" command
2667 -83 common/cmd_net.c some error in automatic boot or "source" command
2668 84 common/cmd_net.c end without errors
2673 100 common/cmd_bootm.c Kernel FIT Image has correct format
2674 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2675 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2676 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2677 102 common/cmd_bootm.c Kernel unit name specified
2678 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2679 103 common/cmd_bootm.c Found configuration node
2680 104 common/cmd_bootm.c Got kernel subimage node offset
2681 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2682 105 common/cmd_bootm.c Kernel subimage hash verification OK
2683 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2684 106 common/cmd_bootm.c Architecture check OK
2685 -106 common/cmd_bootm.c Kernel subimage has wrong type
2686 107 common/cmd_bootm.c Kernel subimage type OK
2687 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2688 108 common/cmd_bootm.c Got kernel subimage data/size
2689 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2690 -109 common/cmd_bootm.c Can't get kernel subimage type
2691 -110 common/cmd_bootm.c Can't get kernel subimage comp
2692 -111 common/cmd_bootm.c Can't get kernel subimage os
2693 -112 common/cmd_bootm.c Can't get kernel subimage load address
2694 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2696 120 common/image.c Start initial ramdisk verification
2697 -120 common/image.c Ramdisk FIT image has incorrect format
2698 121 common/image.c Ramdisk FIT image has correct format
2699 122 common/image.c No ramdisk subimage unit name, using configuration
2700 -122 common/image.c Can't get configuration for ramdisk subimage
2701 123 common/image.c Ramdisk unit name specified
2702 -124 common/image.c Can't get ramdisk subimage node offset
2703 125 common/image.c Got ramdisk subimage node offset
2704 -125 common/image.c Ramdisk subimage hash verification failed
2705 126 common/image.c Ramdisk subimage hash verification OK
2706 -126 common/image.c Ramdisk subimage for unsupported architecture
2707 127 common/image.c Architecture check OK
2708 -127 common/image.c Can't get ramdisk subimage data/size
2709 128 common/image.c Got ramdisk subimage data/size
2710 129 common/image.c Can't get ramdisk load address
2711 -129 common/image.c Got ramdisk load address
2713 -130 common/cmd_doc.c Incorrect FIT image format
2714 131 common/cmd_doc.c FIT image format OK
2716 -140 common/cmd_ide.c Incorrect FIT image format
2717 141 common/cmd_ide.c FIT image format OK
2719 -150 common/cmd_nand.c Incorrect FIT image format
2720 151 common/cmd_nand.c FIT image format OK
2722 - legacy image format:
2723 CONFIG_IMAGE_FORMAT_LEGACY
2724 enables the legacy image format support in U-Boot.
2727 enabled if CONFIG_FIT_SIGNATURE is not defined.
2729 CONFIG_DISABLE_IMAGE_LEGACY
2730 disable the legacy image format
2732 This define is introduced, as the legacy image format is
2733 enabled per default for backward compatibility.
2735 - Standalone program support:
2736 CONFIG_STANDALONE_LOAD_ADDR
2738 This option defines a board specific value for the
2739 address where standalone program gets loaded, thus
2740 overwriting the architecture dependent default
2743 - Frame Buffer Address:
2746 Define CONFIG_FB_ADDR if you want to use specific
2747 address for frame buffer. This is typically the case
2748 when using a graphics controller has separate video
2749 memory. U-Boot will then place the frame buffer at
2750 the given address instead of dynamically reserving it
2751 in system RAM by calling lcd_setmem(), which grabs
2752 the memory for the frame buffer depending on the
2753 configured panel size.
2755 Please see board_init_f function.
2757 - Automatic software updates via TFTP server
2759 CONFIG_UPDATE_TFTP_CNT_MAX
2760 CONFIG_UPDATE_TFTP_MSEC_MAX
2762 These options enable and control the auto-update feature;
2763 for a more detailed description refer to doc/README.update.
2765 - MTD Support (mtdparts command, UBI support)
2768 Adds the MTD device infrastructure from the Linux kernel.
2769 Needed for mtdparts command support.
2771 CONFIG_MTD_PARTITIONS
2773 Adds the MTD partitioning infrastructure from the Linux
2774 kernel. Needed for UBI support.
2777 CONFIG_UBI_SILENCE_MSG
2779 Make the verbose messages from UBI stop printing. This leaves
2780 warnings and errors enabled.
2783 CONFIG_MTD_UBI_WL_THRESHOLD
2784 This parameter defines the maximum difference between the highest
2785 erase counter value and the lowest erase counter value of eraseblocks
2786 of UBI devices. When this threshold is exceeded, UBI starts performing
2787 wear leveling by means of moving data from eraseblock with low erase
2788 counter to eraseblocks with high erase counter.
2790 The default value should be OK for SLC NAND flashes, NOR flashes and
2791 other flashes which have eraseblock life-cycle 100000 or more.
2792 However, in case of MLC NAND flashes which typically have eraseblock
2793 life-cycle less than 10000, the threshold should be lessened (e.g.,
2794 to 128 or 256, although it does not have to be power of 2).
2798 CONFIG_MTD_UBI_BEB_LIMIT
2799 This option specifies the maximum bad physical eraseblocks UBI
2800 expects on the MTD device (per 1024 eraseblocks). If the
2801 underlying flash does not admit of bad eraseblocks (e.g. NOR
2802 flash), this value is ignored.
2804 NAND datasheets often specify the minimum and maximum NVM
2805 (Number of Valid Blocks) for the flashes' endurance lifetime.
2806 The maximum expected bad eraseblocks per 1024 eraseblocks
2807 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2808 which gives 20 for most NANDs (MaxNVB is basically the total
2809 count of eraseblocks on the chip).
2811 To put it differently, if this value is 20, UBI will try to
2812 reserve about 1.9% of physical eraseblocks for bad blocks
2813 handling. And that will be 1.9% of eraseblocks on the entire
2814 NAND chip, not just the MTD partition UBI attaches. This means
2815 that if you have, say, a NAND flash chip admits maximum 40 bad
2816 eraseblocks, and it is split on two MTD partitions of the same
2817 size, UBI will reserve 40 eraseblocks when attaching a
2822 CONFIG_MTD_UBI_FASTMAP
2823 Fastmap is a mechanism which allows attaching an UBI device
2824 in nearly constant time. Instead of scanning the whole MTD device it
2825 only has to locate a checkpoint (called fastmap) on the device.
2826 The on-flash fastmap contains all information needed to attach
2827 the device. Using fastmap makes only sense on large devices where
2828 attaching by scanning takes long. UBI will not automatically install
2829 a fastmap on old images, but you can set the UBI parameter
2830 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2831 that fastmap-enabled images are still usable with UBI implementations
2832 without fastmap support. On typical flash devices the whole fastmap
2833 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2835 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2836 Set this parameter to enable fastmap automatically on images
2840 CONFIG_MTD_UBI_FM_DEBUG
2841 Enable UBI fastmap debug
2845 CONFIG_UBIFS_SILENCE_MSG
2847 Make the verbose messages from UBIFS stop printing. This leaves
2848 warnings and errors enabled.
2852 Enable building of SPL globally.
2855 LDSCRIPT for linking the SPL binary.
2857 CONFIG_SPL_MAX_FOOTPRINT
2858 Maximum size in memory allocated to the SPL, BSS included.
2859 When defined, the linker checks that the actual memory
2860 used by SPL from _start to __bss_end does not exceed it.
2861 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2862 must not be both defined at the same time.
2865 Maximum size of the SPL image (text, data, rodata, and
2866 linker lists sections), BSS excluded.
2867 When defined, the linker checks that the actual size does
2870 CONFIG_SPL_TEXT_BASE
2871 TEXT_BASE for linking the SPL binary.
2873 CONFIG_SPL_RELOC_TEXT_BASE
2874 Address to relocate to. If unspecified, this is equal to
2875 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2877 CONFIG_SPL_BSS_START_ADDR
2878 Link address for the BSS within the SPL binary.
2880 CONFIG_SPL_BSS_MAX_SIZE
2881 Maximum size in memory allocated to the SPL BSS.
2882 When defined, the linker checks that the actual memory used
2883 by SPL from __bss_start to __bss_end does not exceed it.
2884 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2885 must not be both defined at the same time.
2888 Adress of the start of the stack SPL will use
2890 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2891 When defined, SPL will panic() if the image it has
2892 loaded does not have a signature.
2893 Defining this is useful when code which loads images
2894 in SPL cannot guarantee that absolutely all read errors
2896 An example is the LPC32XX MLC NAND driver, which will
2897 consider that a completely unreadable NAND block is bad,
2898 and thus should be skipped silently.
2900 CONFIG_SPL_RELOC_STACK
2901 Adress of the start of the stack SPL will use after
2902 relocation. If unspecified, this is equal to
2905 CONFIG_SYS_SPL_MALLOC_START
2906 Starting address of the malloc pool used in SPL.
2907 When this option is set the full malloc is used in SPL and
2908 it is set up by spl_init() and before that, the simple malloc()
2909 can be used if CONFIG_SYS_MALLOC_F is defined.
2911 CONFIG_SYS_SPL_MALLOC_SIZE
2912 The size of the malloc pool used in SPL.
2914 CONFIG_SPL_FRAMEWORK
2915 Enable the SPL framework under common/. This framework
2916 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2917 NAND loading of the Linux Kernel.
2920 Enable booting directly to an OS from SPL.
2921 See also: doc/README.falcon
2923 CONFIG_SPL_DISPLAY_PRINT
2924 For ARM, enable an optional function to print more information
2925 about the running system.
2927 CONFIG_SPL_INIT_MINIMAL
2928 Arch init code should be built for a very small image
2930 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2931 Partition on the MMC to load U-Boot from when the MMC is being
2934 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2935 Sector to load kernel uImage from when MMC is being
2936 used in raw mode (for Falcon mode)
2938 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2939 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2940 Sector and number of sectors to load kernel argument
2941 parameters from when MMC is being used in raw mode
2944 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2945 Partition on the MMC to load U-Boot from when the MMC is being
2948 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2949 Filename to read to load U-Boot when reading from filesystem
2951 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2952 Filename to read to load kernel uImage when reading
2953 from filesystem (for Falcon mode)
2955 CONFIG_SPL_FS_LOAD_ARGS_NAME
2956 Filename to read to load kernel argument parameters
2957 when reading from filesystem (for Falcon mode)
2959 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2960 Set this for NAND SPL on PPC mpc83xx targets, so that
2961 start.S waits for the rest of the SPL to load before
2962 continuing (the hardware starts execution after just
2963 loading the first page rather than the full 4K).
2965 CONFIG_SPL_SKIP_RELOCATE
2966 Avoid SPL relocation
2968 CONFIG_SPL_NAND_BASE
2969 Include nand_base.c in the SPL. Requires
2970 CONFIG_SPL_NAND_DRIVERS.
2972 CONFIG_SPL_NAND_DRIVERS
2973 SPL uses normal NAND drivers, not minimal drivers.
2976 Include standard software ECC in the SPL
2978 CONFIG_SPL_NAND_SIMPLE
2979 Support for NAND boot using simple NAND drivers that
2980 expose the cmd_ctrl() interface.
2983 Support for a lightweight UBI (fastmap) scanner and
2986 CONFIG_SPL_NAND_RAW_ONLY
2987 Support to boot only raw u-boot.bin images. Use this only
2988 if you need to save space.
2990 CONFIG_SPL_COMMON_INIT_DDR
2991 Set for common ddr init with serial presence detect in
2994 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2995 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2996 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2997 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2998 CONFIG_SYS_NAND_ECCBYTES
2999 Defines the size and behavior of the NAND that SPL uses
3002 CONFIG_SPL_NAND_BOOT
3003 Add support NAND boot
3005 CONFIG_SYS_NAND_U_BOOT_OFFS
3006 Location in NAND to read U-Boot from
3008 CONFIG_SYS_NAND_U_BOOT_DST
3009 Location in memory to load U-Boot to
3011 CONFIG_SYS_NAND_U_BOOT_SIZE
3012 Size of image to load
3014 CONFIG_SYS_NAND_U_BOOT_START
3015 Entry point in loaded image to jump to
3017 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3018 Define this if you need to first read the OOB and then the
3019 data. This is used, for example, on davinci platforms.
3021 CONFIG_SPL_OMAP3_ID_NAND
3022 Support for an OMAP3-specific set of functions to return the
3023 ID and MFR of the first attached NAND chip, if present.
3025 CONFIG_SPL_RAM_DEVICE
3026 Support for running image already present in ram, in SPL binary
3029 Image offset to which the SPL should be padded before appending
3030 the SPL payload. By default, this is defined as
3031 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3032 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3033 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3036 Final target image containing SPL and payload. Some SPLs
3037 use an arch-specific makefile fragment instead, for
3038 example if more than one image needs to be produced.
3040 CONFIG_FIT_SPL_PRINT
3041 Printing information about a FIT image adds quite a bit of
3042 code to SPL. So this is normally disabled in SPL. Use this
3043 option to re-enable it. This will affect the output of the
3044 bootm command when booting a FIT image.
3048 Enable building of TPL globally.
3051 Image offset to which the TPL should be padded before appending
3052 the TPL payload. By default, this is defined as
3053 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3054 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3055 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3057 - Interrupt support (PPC):
3059 There are common interrupt_init() and timer_interrupt()
3060 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3061 for CPU specific initialization. interrupt_init_cpu()
3062 should set decrementer_count to appropriate value. If
3063 CPU resets decrementer automatically after interrupt
3064 (ppc4xx) it should set decrementer_count to zero.
3065 timer_interrupt() calls timer_interrupt_cpu() for CPU
3066 specific handling. If board has watchdog / status_led
3067 / other_activity_monitor it works automatically from
3068 general timer_interrupt().
3071 Board initialization settings:
3072 ------------------------------
3074 During Initialization u-boot calls a number of board specific functions
3075 to allow the preparation of board specific prerequisites, e.g. pin setup
3076 before drivers are initialized. To enable these callbacks the
3077 following configuration macros have to be defined. Currently this is
3078 architecture specific, so please check arch/your_architecture/lib/board.c
3079 typically in board_init_f() and board_init_r().
3081 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3082 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3083 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3084 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3086 Configuration Settings:
3087 -----------------------
3089 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3090 Optionally it can be defined to support 64-bit memory commands.
3092 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3093 undefine this when you're short of memory.
3095 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3096 width of the commands listed in the 'help' command output.
3098 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3099 prompt for user input.
3101 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3103 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3105 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3107 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3108 the application (usually a Linux kernel) when it is
3111 - CONFIG_SYS_BAUDRATE_TABLE:
3112 List of legal baudrate settings for this board.
3114 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3115 Begin and End addresses of the area used by the
3118 - CONFIG_SYS_ALT_MEMTEST:
3119 Enable an alternate, more extensive memory test.
3121 - CONFIG_SYS_MEMTEST_SCRATCH:
3122 Scratch address used by the alternate memory test
3123 You only need to set this if address zero isn't writeable
3125 - CONFIG_SYS_MEM_RESERVE_SECURE
3126 Only implemented for ARMv8 for now.
3127 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3128 is substracted from total RAM and won't be reported to OS.
3129 This memory can be used as secure memory. A variable
3130 gd->arch.secure_ram is used to track the location. In systems
3131 the RAM base is not zero, or RAM is divided into banks,
3132 this variable needs to be recalcuated to get the address.
3134 - CONFIG_SYS_MEM_TOP_HIDE:
3135 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3136 this specified memory area will get subtracted from the top
3137 (end) of RAM and won't get "touched" at all by U-Boot. By
3138 fixing up gd->ram_size the Linux kernel should gets passed
3139 the now "corrected" memory size and won't touch it either.
3140 This should work for arch/ppc and arch/powerpc. Only Linux
3141 board ports in arch/powerpc with bootwrapper support that
3142 recalculate the memory size from the SDRAM controller setup
3143 will have to get fixed in Linux additionally.
3145 This option can be used as a workaround for the 440EPx/GRx
3146 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3149 WARNING: Please make sure that this value is a multiple of
3150 the Linux page size (normally 4k). If this is not the case,
3151 then the end address of the Linux memory will be located at a
3152 non page size aligned address and this could cause major
3155 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3156 Enable temporary baudrate change while serial download
3158 - CONFIG_SYS_SDRAM_BASE:
3159 Physical start address of SDRAM. _Must_ be 0 here.
3161 - CONFIG_SYS_FLASH_BASE:
3162 Physical start address of Flash memory.
3164 - CONFIG_SYS_MONITOR_BASE:
3165 Physical start address of boot monitor code (set by
3166 make config files to be same as the text base address
3167 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3168 CONFIG_SYS_FLASH_BASE when booting from flash.
3170 - CONFIG_SYS_MONITOR_LEN:
3171 Size of memory reserved for monitor code, used to
3172 determine _at_compile_time_ (!) if the environment is
3173 embedded within the U-Boot image, or in a separate
3176 - CONFIG_SYS_MALLOC_LEN:
3177 Size of DRAM reserved for malloc() use.
3179 - CONFIG_SYS_MALLOC_F_LEN
3180 Size of the malloc() pool for use before relocation. If
3181 this is defined, then a very simple malloc() implementation
3182 will become available before relocation. The address is just
3183 below the global data, and the stack is moved down to make
3186 This feature allocates regions with increasing addresses
3187 within the region. calloc() is supported, but realloc()
3188 is not available. free() is supported but does nothing.
3189 The memory will be freed (or in fact just forgotten) when
3190 U-Boot relocates itself.
3192 - CONFIG_SYS_MALLOC_SIMPLE
3193 Provides a simple and small malloc() and calloc() for those
3194 boards which do not use the full malloc in SPL (which is
3195 enabled with CONFIG_SYS_SPL_MALLOC_START).
3197 - CONFIG_SYS_NONCACHED_MEMORY:
3198 Size of non-cached memory area. This area of memory will be
3199 typically located right below the malloc() area and mapped
3200 uncached in the MMU. This is useful for drivers that would
3201 otherwise require a lot of explicit cache maintenance. For
3202 some drivers it's also impossible to properly maintain the
3203 cache. For example if the regions that need to be flushed
3204 are not a multiple of the cache-line size, *and* padding
3205 cannot be allocated between the regions to align them (i.e.
3206 if the HW requires a contiguous array of regions, and the
3207 size of each region is not cache-aligned), then a flush of
3208 one region may result in overwriting data that hardware has
3209 written to another region in the same cache-line. This can
3210 happen for example in network drivers where descriptors for
3211 buffers are typically smaller than the CPU cache-line (e.g.
3212 16 bytes vs. 32 or 64 bytes).
3214 Non-cached memory is only supported on 32-bit ARM at present.
3216 - CONFIG_SYS_BOOTM_LEN:
3217 Normally compressed uImages are limited to an
3218 uncompressed size of 8 MBytes. If this is not enough,
3219 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3220 to adjust this setting to your needs.
3222 - CONFIG_SYS_BOOTMAPSZ:
3223 Maximum size of memory mapped by the startup code of
3224 the Linux kernel; all data that must be processed by
3225 the Linux kernel (bd_info, boot arguments, FDT blob if
3226 used) must be put below this limit, unless "bootm_low"
3227 environment variable is defined and non-zero. In such case
3228 all data for the Linux kernel must be between "bootm_low"
3229 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3230 variable "bootm_mapsize" will override the value of
3231 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3232 then the value in "bootm_size" will be used instead.
3234 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3235 Enable initrd_high functionality. If defined then the
3236 initrd_high feature is enabled and the bootm ramdisk subcommand
3239 - CONFIG_SYS_BOOT_GET_CMDLINE:
3240 Enables allocating and saving kernel cmdline in space between
3241 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3243 - CONFIG_SYS_BOOT_GET_KBD:
3244 Enables allocating and saving a kernel copy of the bd_info in
3245 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3247 - CONFIG_SYS_MAX_FLASH_BANKS:
3248 Max number of Flash memory banks
3250 - CONFIG_SYS_MAX_FLASH_SECT:
3251 Max number of sectors on a Flash chip
3253 - CONFIG_SYS_FLASH_ERASE_TOUT:
3254 Timeout for Flash erase operations (in ms)
3256 - CONFIG_SYS_FLASH_WRITE_TOUT:
3257 Timeout for Flash write operations (in ms)
3259 - CONFIG_SYS_FLASH_LOCK_TOUT
3260 Timeout for Flash set sector lock bit operation (in ms)
3262 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3263 Timeout for Flash clear lock bits operation (in ms)
3265 - CONFIG_SYS_FLASH_PROTECTION
3266 If defined, hardware flash sectors protection is used
3267 instead of U-Boot software protection.
3269 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3271 Enable TFTP transfers directly to flash memory;
3272 without this option such a download has to be
3273 performed in two steps: (1) download to RAM, and (2)
3274 copy from RAM to flash.
3276 The two-step approach is usually more reliable, since
3277 you can check if the download worked before you erase
3278 the flash, but in some situations (when system RAM is
3279 too limited to allow for a temporary copy of the
3280 downloaded image) this option may be very useful.
3282 - CONFIG_SYS_FLASH_CFI:
3283 Define if the flash driver uses extra elements in the
3284 common flash structure for storing flash geometry.
3286 - CONFIG_FLASH_CFI_DRIVER
3287 This option also enables the building of the cfi_flash driver
3288 in the drivers directory
3290 - CONFIG_FLASH_CFI_MTD
3291 This option enables the building of the cfi_mtd driver
3292 in the drivers directory. The driver exports CFI flash
3295 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3296 Use buffered writes to flash.
3298 - CONFIG_FLASH_SPANSION_S29WS_N
3299 s29ws-n MirrorBit flash has non-standard addresses for buffered
3302 - CONFIG_SYS_FLASH_QUIET_TEST
3303 If this option is defined, the common CFI flash doesn't
3304 print it's warning upon not recognized FLASH banks. This
3305 is useful, if some of the configured banks are only
3306 optionally available.
3308 - CONFIG_FLASH_SHOW_PROGRESS
3309 If defined (must be an integer), print out countdown
3310 digits and dots. Recommended value: 45 (9..1) for 80
3311 column displays, 15 (3..1) for 40 column displays.
3313 - CONFIG_FLASH_VERIFY
3314 If defined, the content of the flash (destination) is compared
3315 against the source after the write operation. An error message
3316 will be printed when the contents are not identical.
3317 Please note that this option is useless in nearly all cases,
3318 since such flash programming errors usually are detected earlier
3319 while unprotecting/erasing/programming. Please only enable
3320 this option if you really know what you are doing.
3322 - CONFIG_SYS_RX_ETH_BUFFER:
3323 Defines the number of Ethernet receive buffers. On some
3324 Ethernet controllers it is recommended to set this value
3325 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3326 buffers can be full shortly after enabling the interface
3327 on high Ethernet traffic.
3328 Defaults to 4 if not defined.
3330 - CONFIG_ENV_MAX_ENTRIES
3332 Maximum number of entries in the hash table that is used
3333 internally to store the environment settings. The default
3334 setting is supposed to be generous and should work in most
3335 cases. This setting can be used to tune behaviour; see
3336 lib/hashtable.c for details.
3338 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3339 - CONFIG_ENV_FLAGS_LIST_STATIC
3340 Enable validation of the values given to environment variables when
3341 calling env set. Variables can be restricted to only decimal,
3342 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3343 the variables can also be restricted to IP address or MAC address.
3345 The format of the list is:
3346 type_attribute = [s|d|x|b|i|m]
3347 access_attribute = [a|r|o|c]
3348 attributes = type_attribute[access_attribute]
3349 entry = variable_name[:attributes]
3352 The type attributes are:
3353 s - String (default)
3356 b - Boolean ([1yYtT|0nNfF])
3360 The access attributes are:
3366 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3367 Define this to a list (string) to define the ".flags"
3368 environment variable in the default or embedded environment.
3370 - CONFIG_ENV_FLAGS_LIST_STATIC
3371 Define this to a list (string) to define validation that
3372 should be done if an entry is not found in the ".flags"
3373 environment variable. To override a setting in the static
3374 list, simply add an entry for the same variable name to the
3377 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3378 regular expression. This allows multiple variables to define the same
3379 flags without explicitly listing them for each variable.
3381 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3382 If defined, don't allow the -f switch to env set override variable
3386 If stdint.h is available with your toolchain you can define this
3387 option to enable it. You can provide option 'USE_STDINT=1' when
3388 building U-Boot to enable this.
3390 The following definitions that deal with the placement and management
3391 of environment data (variable area); in general, we support the
3392 following configurations:
3394 - CONFIG_BUILD_ENVCRC:
3396 Builds up envcrc with the target environment so that external utils
3397 may easily extract it and embed it in final U-Boot images.
3399 BE CAREFUL! The first access to the environment happens quite early
3400 in U-Boot initialization (when we try to get the setting of for the
3401 console baudrate). You *MUST* have mapped your NVRAM area then, or
3404 Please note that even with NVRAM we still use a copy of the
3405 environment in RAM: we could work on NVRAM directly, but we want to
3406 keep settings there always unmodified except somebody uses "saveenv"
3407 to save the current settings.
3409 BE CAREFUL! For some special cases, the local device can not use
3410 "saveenv" command. For example, the local device will get the
3411 environment stored in a remote NOR flash by SRIO or PCIE link,
3412 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3414 - CONFIG_NAND_ENV_DST
3416 Defines address in RAM to which the nand_spl code should copy the
3417 environment. If redundant environment is used, it will be copied to
3418 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3420 Please note that the environment is read-only until the monitor
3421 has been relocated to RAM and a RAM copy of the environment has been
3422 created; also, when using EEPROM you will have to use getenv_f()
3423 until then to read environment variables.
3425 The environment is protected by a CRC32 checksum. Before the monitor
3426 is relocated into RAM, as a result of a bad CRC you will be working
3427 with the compiled-in default environment - *silently*!!! [This is
3428 necessary, because the first environment variable we need is the
3429 "baudrate" setting for the console - if we have a bad CRC, we don't
3430 have any device yet where we could complain.]
3432 Note: once the monitor has been relocated, then it will complain if
3433 the default environment is used; a new CRC is computed as soon as you
3434 use the "saveenv" command to store a valid environment.
3436 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3437 Echo the inverted Ethernet link state to the fault LED.
3439 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3440 also needs to be defined.
3442 - CONFIG_SYS_FAULT_MII_ADDR:
3443 MII address of the PHY to check for the Ethernet link state.
3445 - CONFIG_NS16550_MIN_FUNCTIONS:
3446 Define this if you desire to only have use of the NS16550_init
3447 and NS16550_putc functions for the serial driver located at
3448 drivers/serial/ns16550.c. This option is useful for saving
3449 space for already greatly restricted images, including but not
3450 limited to NAND_SPL configurations.
3452 - CONFIG_DISPLAY_BOARDINFO
3453 Display information about the board that U-Boot is running on
3454 when U-Boot starts up. The board function checkboard() is called
3457 - CONFIG_DISPLAY_BOARDINFO_LATE
3458 Similar to the previous option, but display this information
3459 later, once stdio is running and output goes to the LCD, if
3462 - CONFIG_BOARD_SIZE_LIMIT:
3463 Maximum size of the U-Boot image. When defined, the
3464 build system checks that the actual size does not
3467 Low Level (hardware related) configuration options:
3468 ---------------------------------------------------
3470 - CONFIG_SYS_CACHELINE_SIZE:
3471 Cache Line Size of the CPU.
3473 - CONFIG_SYS_CCSRBAR_DEFAULT:
3474 Default (power-on reset) physical address of CCSR on Freescale
3477 - CONFIG_SYS_CCSRBAR:
3478 Virtual address of CCSR. On a 32-bit build, this is typically
3479 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3481 - CONFIG_SYS_CCSRBAR_PHYS:
3482 Physical address of CCSR. CCSR can be relocated to a new
3483 physical address, if desired. In this case, this macro should
3484 be set to that address. Otherwise, it should be set to the
3485 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3486 is typically relocated on 36-bit builds. It is recommended
3487 that this macro be defined via the _HIGH and _LOW macros:
3489 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3490 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3492 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3493 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3494 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3495 used in assembly code, so it must not contain typecasts or
3496 integer size suffixes (e.g. "ULL").
3498 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3499 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3500 used in assembly code, so it must not contain typecasts or
3501 integer size suffixes (e.g. "ULL").
3503 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3504 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3505 forced to a value that ensures that CCSR is not relocated.
3507 - Floppy Disk Support:
3508 CONFIG_SYS_FDC_DRIVE_NUMBER
3510 the default drive number (default value 0)
3512 CONFIG_SYS_ISA_IO_STRIDE
3514 defines the spacing between FDC chipset registers
3517 CONFIG_SYS_ISA_IO_OFFSET
3519 defines the offset of register from address. It
3520 depends on which part of the data bus is connected to
3521 the FDC chipset. (default value 0)
3523 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3524 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3527 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3528 fdc_hw_init() is called at the beginning of the FDC
3529 setup. fdc_hw_init() must be provided by the board
3530 source code. It is used to make hardware-dependent
3534 Most IDE controllers were designed to be connected with PCI
3535 interface. Only few of them were designed for AHB interface.
3536 When software is doing ATA command and data transfer to
3537 IDE devices through IDE-AHB controller, some additional
3538 registers accessing to these kind of IDE-AHB controller
3541 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3542 DO NOT CHANGE unless you know exactly what you're
3543 doing! (11-4) [MPC8xx systems only]
3545 - CONFIG_SYS_INIT_RAM_ADDR:
3547 Start address of memory area that can be used for
3548 initial data and stack; please note that this must be
3549 writable memory that is working WITHOUT special
3550 initialization, i. e. you CANNOT use normal RAM which
3551 will become available only after programming the
3552 memory controller and running certain initialization
3555 U-Boot uses the following memory types:
3556 - MPC8xx: IMMR (internal memory of the CPU)
3558 - CONFIG_SYS_GBL_DATA_OFFSET:
3560 Offset of the initial data structure in the memory
3561 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3562 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3563 data is located at the end of the available space
3564 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3565 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3566 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3567 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3570 On the MPC824X (or other systems that use the data
3571 cache for initial memory) the address chosen for
3572 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3573 point to an otherwise UNUSED address space between
3574 the top of RAM and the start of the PCI space.
3576 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3578 - CONFIG_SYS_OR_TIMING_SDRAM:
3581 - CONFIG_SYS_MAMR_PTA:
3582 periodic timer for refresh
3584 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3585 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3586 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3587 CONFIG_SYS_BR1_PRELIM:
3588 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3590 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3591 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3592 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3593 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3595 - CONFIG_PCI_ENUM_ONLY
3596 Only scan through and get the devices on the buses.
3597 Don't do any setup work, presumably because someone or
3598 something has already done it, and we don't need to do it
3599 a second time. Useful for platforms that are pre-booted
3600 by coreboot or similar.
3602 - CONFIG_PCI_INDIRECT_BRIDGE:
3603 Enable support for indirect PCI bridges.
3606 Chip has SRIO or not
3609 Board has SRIO 1 port available
3612 Board has SRIO 2 port available
3614 - CONFIG_SRIO_PCIE_BOOT_MASTER
3615 Board can support master function for Boot from SRIO and PCIE
3617 - CONFIG_SYS_SRIOn_MEM_VIRT:
3618 Virtual Address of SRIO port 'n' memory region
3620 - CONFIG_SYS_SRIOn_MEM_PHYS:
3621 Physical Address of SRIO port 'n' memory region
3623 - CONFIG_SYS_SRIOn_MEM_SIZE:
3624 Size of SRIO port 'n' memory region
3626 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3627 Defined to tell the NAND controller that the NAND chip is using
3629 Not all NAND drivers use this symbol.
3630 Example of drivers that use it:
3631 - drivers/mtd/nand/ndfc.c
3632 - drivers/mtd/nand/mxc_nand.c
3634 - CONFIG_SYS_NDFC_EBC0_CFG
3635 Sets the EBC0_CFG register for the NDFC. If not defined
3636 a default value will be used.
3639 Get DDR timing information from an I2C EEPROM. Common
3640 with pluggable memory modules such as SODIMMs
3643 I2C address of the SPD EEPROM
3645 - CONFIG_SYS_SPD_BUS_NUM
3646 If SPD EEPROM is on an I2C bus other than the first
3647 one, specify here. Note that the value must resolve
3648 to something your driver can deal with.
3650 - CONFIG_SYS_DDR_RAW_TIMING
3651 Get DDR timing information from other than SPD. Common with
3652 soldered DDR chips onboard without SPD. DDR raw timing
3653 parameters are extracted from datasheet and hard-coded into
3654 header files or board specific files.
3656 - CONFIG_FSL_DDR_INTERACTIVE
3657 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3659 - CONFIG_FSL_DDR_SYNC_REFRESH
3660 Enable sync of refresh for multiple controllers.
3662 - CONFIG_FSL_DDR_BIST
3663 Enable built-in memory test for Freescale DDR controllers.
3665 - CONFIG_SYS_83XX_DDR_USES_CS0
3666 Only for 83xx systems. If specified, then DDR should
3667 be configured using CS0 and CS1 instead of CS2 and CS3.
3670 Enable RMII mode for all FECs.
3671 Note that this is a global option, we can't
3672 have one FEC in standard MII mode and another in RMII mode.
3674 - CONFIG_CRC32_VERIFY
3675 Add a verify option to the crc32 command.
3678 => crc32 -v <address> <count> <crc32>
3680 Where address/count indicate a memory area
3681 and crc32 is the correct crc32 which the
3685 Add the "loopw" memory command. This only takes effect if
3686 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3689 Add the "mdc" and "mwc" memory commands. These are cyclic
3694 This command will print 4 bytes (10,11,12,13) each 500 ms.
3696 => mwc.l 100 12345678 10
3697 This command will write 12345678 to address 100 all 10 ms.
3699 This only takes effect if the memory commands are activated
3700 globally (CONFIG_CMD_MEMORY).
3702 - CONFIG_SKIP_LOWLEVEL_INIT
3703 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3704 low level initializations (like setting up the memory
3705 controller) are omitted and/or U-Boot does not
3706 relocate itself into RAM.
3708 Normally this variable MUST NOT be defined. The only
3709 exception is when U-Boot is loaded (to RAM) by some
3710 other boot loader or by a debugger which performs
3711 these initializations itself.
3713 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3714 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3715 to be skipped. The normal CP15 init (such as enabling the
3716 instruction cache) is still performed.
3719 Modifies the behaviour of start.S when compiling a loader
3720 that is executed before the actual U-Boot. E.g. when
3721 compiling a NAND SPL.
3724 Modifies the behaviour of start.S when compiling a loader
3725 that is executed after the SPL and before the actual U-Boot.
3726 It is loaded by the SPL.
3728 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3729 Only for 85xx systems. If this variable is specified, the section
3730 .resetvec is not kept and the section .bootpg is placed in the
3731 previous 4k of the .text section.
3733 - CONFIG_ARCH_MAP_SYSMEM
3734 Generally U-Boot (and in particular the md command) uses
3735 effective address. It is therefore not necessary to regard
3736 U-Boot address as virtual addresses that need to be translated
3737 to physical addresses. However, sandbox requires this, since
3738 it maintains its own little RAM buffer which contains all
3739 addressable memory. This option causes some memory accesses
3740 to be mapped through map_sysmem() / unmap_sysmem().
3742 - CONFIG_X86_RESET_VECTOR
3743 If defined, the x86 reset vector code is included. This is not
3744 needed when U-Boot is running from Coreboot.
3746 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3747 Enables the RTC32K OSC on AM33xx based plattforms
3749 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3750 Option to disable subpage write in NAND driver
3751 driver that uses this:
3752 drivers/mtd/nand/davinci_nand.c
3754 Freescale QE/FMAN Firmware Support:
3755 -----------------------------------
3757 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3758 loading of "firmware", which is encoded in the QE firmware binary format.
3759 This firmware often needs to be loaded during U-Boot booting, so macros
3760 are used to identify the storage device (NOR flash, SPI, etc) and the address
3763 - CONFIG_SYS_FMAN_FW_ADDR
3764 The address in the storage device where the FMAN microcode is located. The
3765 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3768 - CONFIG_SYS_QE_FW_ADDR
3769 The address in the storage device where the QE microcode is located. The
3770 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3773 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3774 The maximum possible size of the firmware. The firmware binary format
3775 has a field that specifies the actual size of the firmware, but it
3776 might not be possible to read any part of the firmware unless some
3777 local storage is allocated to hold the entire firmware first.
3779 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3780 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3781 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3782 virtual address in NOR flash.
3784 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3785 Specifies that QE/FMAN firmware is located in NAND flash.
3786 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3788 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3789 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3790 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3792 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3793 Specifies that QE/FMAN firmware is located in the remote (master)
3794 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3795 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3796 window->master inbound window->master LAW->the ucode address in
3797 master's memory space.
3799 Freescale Layerscape Management Complex Firmware Support:
3800 ---------------------------------------------------------
3801 The Freescale Layerscape Management Complex (MC) supports the loading of
3803 This firmware often needs to be loaded during U-Boot booting, so macros
3804 are used to identify the storage device (NOR flash, SPI, etc) and the address
3807 - CONFIG_FSL_MC_ENET
3808 Enable the MC driver for Layerscape SoCs.
3810 Freescale Layerscape Debug Server Support:
3811 -------------------------------------------
3812 The Freescale Layerscape Debug Server Support supports the loading of
3813 "Debug Server firmware" and triggering SP boot-rom.
3814 This firmware often needs to be loaded during U-Boot booting.
3816 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3817 Define alignment of reserved memory MC requires
3822 In order to achieve reproducible builds, timestamps used in the U-Boot build
3823 process have to be set to a fixed value.
3825 This is done using the SOURCE_DATE_EPOCH environment variable.
3826 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3827 option for U-Boot or an environment variable in U-Boot.
3829 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3831 Building the Software:
3832 ======================
3834 Building U-Boot has been tested in several native build environments
3835 and in many different cross environments. Of course we cannot support
3836 all possibly existing versions of cross development tools in all
3837 (potentially obsolete) versions. In case of tool chain problems we
3838 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3839 which is extensively used to build and test U-Boot.
3841 If you are not using a native environment, it is assumed that you
3842 have GNU cross compiling tools available in your path. In this case,
3843 you must set the environment variable CROSS_COMPILE in your shell.
3844 Note that no changes to the Makefile or any other source files are
3845 necessary. For example using the ELDK on a 4xx CPU, please enter:
3847 $ CROSS_COMPILE=ppc_4xx-
3848 $ export CROSS_COMPILE
3850 Note: If you wish to generate Windows versions of the utilities in
3851 the tools directory you can use the MinGW toolchain
3852 (http://www.mingw.org). Set your HOST tools to the MinGW
3853 toolchain and execute 'make tools'. For example:
3855 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3857 Binaries such as tools/mkimage.exe will be created which can
3858 be executed on computers running Windows.
3860 U-Boot is intended to be simple to build. After installing the
3861 sources you must configure U-Boot for one specific board type. This
3866 where "NAME_defconfig" is the name of one of the existing configu-
3867 rations; see boards.cfg for supported names.
3869 Note: for some board special configuration names may exist; check if
3870 additional information is available from the board vendor; for
3871 instance, the TQM823L systems are available without (standard)
3872 or with LCD support. You can select such additional "features"
3873 when choosing the configuration, i. e.
3875 make TQM823L_defconfig
3876 - will configure for a plain TQM823L, i. e. no LCD support
3878 make TQM823L_LCD_defconfig
3879 - will configure for a TQM823L with U-Boot console on LCD
3884 Finally, type "make all", and you should get some working U-Boot
3885 images ready for download to / installation on your system:
3887 - "u-boot.bin" is a raw binary image
3888 - "u-boot" is an image in ELF binary format
3889 - "u-boot.srec" is in Motorola S-Record format
3891 By default the build is performed locally and the objects are saved
3892 in the source directory. One of the two methods can be used to change
3893 this behavior and build U-Boot to some external directory:
3895 1. Add O= to the make command line invocations:
3897 make O=/tmp/build distclean
3898 make O=/tmp/build NAME_defconfig
3899 make O=/tmp/build all
3901 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3903 export KBUILD_OUTPUT=/tmp/build
3908 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3912 Please be aware that the Makefiles assume you are using GNU make, so
3913 for instance on NetBSD you might need to use "gmake" instead of
3917 If the system board that you have is not listed, then you will need
3918 to port U-Boot to your hardware platform. To do this, follow these
3921 1. Create a new directory to hold your board specific code. Add any
3922 files you need. In your board directory, you will need at least
3923 the "Makefile" and a "<board>.c".
3924 2. Create a new configuration file "include/configs/<board>.h" for
3926 3. If you're porting U-Boot to a new CPU, then also create a new
3927 directory to hold your CPU specific code. Add any files you need.
3928 4. Run "make <board>_defconfig" with your new name.
3929 5. Type "make", and you should get a working "u-boot.srec" file
3930 to be installed on your target system.
3931 6. Debug and solve any problems that might arise.
3932 [Of course, this last step is much harder than it sounds.]
3935 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3936 ==============================================================
3938 If you have modified U-Boot sources (for instance added a new board
3939 or support for new devices, a new CPU, etc.) you are expected to
3940 provide feedback to the other developers. The feedback normally takes
3941 the form of a "patch", i. e. a context diff against a certain (latest
3942 official or latest in the git repository) version of U-Boot sources.
3944 But before you submit such a patch, please verify that your modifi-
3945 cation did not break existing code. At least make sure that *ALL* of
3946 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3947 just run the buildman script (tools/buildman/buildman), which will
3948 configure and build U-Boot for ALL supported system. Be warned, this
3949 will take a while. Please see the buildman README, or run 'buildman -H'
3953 See also "U-Boot Porting Guide" below.
3956 Monitor Commands - Overview:
3957 ============================
3959 go - start application at address 'addr'
3960 run - run commands in an environment variable
3961 bootm - boot application image from memory
3962 bootp - boot image via network using BootP/TFTP protocol
3963 bootz - boot zImage from memory
3964 tftpboot- boot image via network using TFTP protocol
3965 and env variables "ipaddr" and "serverip"
3966 (and eventually "gatewayip")
3967 tftpput - upload a file via network using TFTP protocol
3968 rarpboot- boot image via network using RARP/TFTP protocol
3969 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3970 loads - load S-Record file over serial line
3971 loadb - load binary file over serial line (kermit mode)
3973 mm - memory modify (auto-incrementing)
3974 nm - memory modify (constant address)
3975 mw - memory write (fill)
3977 cmp - memory compare
3978 crc32 - checksum calculation
3979 i2c - I2C sub-system
3980 sspi - SPI utility commands
3981 base - print or set address offset
3982 printenv- print environment variables
3983 setenv - set environment variables
3984 saveenv - save environment variables to persistent storage
3985 protect - enable or disable FLASH write protection
3986 erase - erase FLASH memory
3987 flinfo - print FLASH memory information
3988 nand - NAND memory operations (see doc/README.nand)
3989 bdinfo - print Board Info structure
3990 iminfo - print header information for application image
3991 coninfo - print console devices and informations
3992 ide - IDE sub-system
3993 loop - infinite loop on address range
3994 loopw - infinite write loop on address range
3995 mtest - simple RAM test
3996 icache - enable or disable instruction cache
3997 dcache - enable or disable data cache
3998 reset - Perform RESET of the CPU
3999 echo - echo args to console
4000 version - print monitor version
4001 help - print online help
4002 ? - alias for 'help'
4005 Monitor Commands - Detailed Description:
4006 ========================================
4010 For now: just type "help <command>".
4013 Environment Variables:
4014 ======================
4016 U-Boot supports user configuration using Environment Variables which
4017 can be made persistent by saving to Flash memory.
4019 Environment Variables are set using "setenv", printed using
4020 "printenv", and saved to Flash using "saveenv". Using "setenv"
4021 without a value can be used to delete a variable from the
4022 environment. As long as you don't save the environment you are
4023 working with an in-memory copy. In case the Flash area containing the
4024 environment is erased by accident, a default environment is provided.
4026 Some configuration options can be set using Environment Variables.
4028 List of environment variables (most likely not complete):
4030 baudrate - see CONFIG_BAUDRATE
4032 bootdelay - see CONFIG_BOOTDELAY
4034 bootcmd - see CONFIG_BOOTCOMMAND
4036 bootargs - Boot arguments when booting an RTOS image
4038 bootfile - Name of the image to load with TFTP
4040 bootm_low - Memory range available for image processing in the bootm
4041 command can be restricted. This variable is given as
4042 a hexadecimal number and defines lowest address allowed
4043 for use by the bootm command. See also "bootm_size"
4044 environment variable. Address defined by "bootm_low" is
4045 also the base of the initial memory mapping for the Linux
4046 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4049 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4050 This variable is given as a hexadecimal number and it
4051 defines the size of the memory region starting at base
4052 address bootm_low that is accessible by the Linux kernel
4053 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4054 as the default value if it is defined, and bootm_size is
4057 bootm_size - Memory range available for image processing in the bootm
4058 command can be restricted. This variable is given as
4059 a hexadecimal number and defines the size of the region
4060 allowed for use by the bootm command. See also "bootm_low"
4061 environment variable.
4063 updatefile - Location of the software update file on a TFTP server, used
4064 by the automatic software update feature. Please refer to
4065 documentation in doc/README.update for more details.
4067 autoload - if set to "no" (any string beginning with 'n'),
4068 "bootp" will just load perform a lookup of the
4069 configuration from the BOOTP server, but not try to
4070 load any image using TFTP
4072 autostart - if set to "yes", an image loaded using the "bootp",
4073 "rarpboot", "tftpboot" or "diskboot" commands will
4074 be automatically started (by internally calling
4077 If set to "no", a standalone image passed to the
4078 "bootm" command will be copied to the load address
4079 (and eventually uncompressed), but NOT be started.
4080 This can be used to load and uncompress arbitrary
4083 fdt_high - if set this restricts the maximum address that the
4084 flattened device tree will be copied into upon boot.
4085 For example, if you have a system with 1 GB memory
4086 at physical address 0x10000000, while Linux kernel
4087 only recognizes the first 704 MB as low memory, you
4088 may need to set fdt_high as 0x3C000000 to have the
4089 device tree blob be copied to the maximum address
4090 of the 704 MB low memory, so that Linux kernel can
4091 access it during the boot procedure.
4093 If this is set to the special value 0xFFFFFFFF then
4094 the fdt will not be copied at all on boot. For this
4095 to work it must reside in writable memory, have
4096 sufficient padding on the end of it for u-boot to
4097 add the information it needs into it, and the memory
4098 must be accessible by the kernel.
4100 fdtcontroladdr- if set this is the address of the control flattened
4101 device tree used by U-Boot when CONFIG_OF_CONTROL is
4104 i2cfast - (PPC405GP|PPC405EP only)
4105 if set to 'y' configures Linux I2C driver for fast
4106 mode (400kHZ). This environment variable is used in
4107 initialization code. So, for changes to be effective
4108 it must be saved and board must be reset.
4110 initrd_high - restrict positioning of initrd images:
4111 If this variable is not set, initrd images will be
4112 copied to the highest possible address in RAM; this
4113 is usually what you want since it allows for
4114 maximum initrd size. If for some reason you want to
4115 make sure that the initrd image is loaded below the
4116 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4117 variable to a value of "no" or "off" or "0".
4118 Alternatively, you can set it to a maximum upper
4119 address to use (U-Boot will still check that it
4120 does not overwrite the U-Boot stack and data).
4122 For instance, when you have a system with 16 MB
4123 RAM, and want to reserve 4 MB from use by Linux,
4124 you can do this by adding "mem=12M" to the value of
4125 the "bootargs" variable. However, now you must make
4126 sure that the initrd image is placed in the first
4127 12 MB as well - this can be done with
4129 setenv initrd_high 00c00000
4131 If you set initrd_high to 0xFFFFFFFF, this is an
4132 indication to U-Boot that all addresses are legal
4133 for the Linux kernel, including addresses in flash
4134 memory. In this case U-Boot will NOT COPY the
4135 ramdisk at all. This may be useful to reduce the
4136 boot time on your system, but requires that this
4137 feature is supported by your Linux kernel.
4139 ipaddr - IP address; needed for tftpboot command
4141 loadaddr - Default load address for commands like "bootp",
4142 "rarpboot", "tftpboot", "loadb" or "diskboot"
4144 loads_echo - see CONFIG_LOADS_ECHO
4146 serverip - TFTP server IP address; needed for tftpboot command
4148 bootretry - see CONFIG_BOOT_RETRY_TIME
4150 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4152 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4154 ethprime - controls which interface is used first.
4156 ethact - controls which interface is currently active.
4157 For example you can do the following
4159 => setenv ethact FEC
4160 => ping 192.168.0.1 # traffic sent on FEC
4161 => setenv ethact SCC
4162 => ping 10.0.0.1 # traffic sent on SCC
4164 ethrotate - When set to "no" U-Boot does not go through all
4165 available network interfaces.
4166 It just stays at the currently selected interface.
4168 netretry - When set to "no" each network operation will
4169 either succeed or fail without retrying.
4170 When set to "once" the network operation will
4171 fail when all the available network interfaces
4172 are tried once without success.
4173 Useful on scripts which control the retry operation
4176 npe_ucode - set load address for the NPE microcode
4178 silent_linux - If set then Linux will be told to boot silently, by
4179 changing the console to be empty. If "yes" it will be
4180 made silent. If "no" it will not be made silent. If
4181 unset, then it will be made silent if the U-Boot console
4184 tftpsrcp - If this is set, the value is used for TFTP's
4187 tftpdstp - If this is set, the value is used for TFTP's UDP
4188 destination port instead of the Well Know Port 69.
4190 tftpblocksize - Block size to use for TFTP transfers; if not set,
4191 we use the TFTP server's default block size
4193 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4194 seconds, minimum value is 1000 = 1 second). Defines
4195 when a packet is considered to be lost so it has to
4196 be retransmitted. The default is 5000 = 5 seconds.
4197 Lowering this value may make downloads succeed
4198 faster in networks with high packet loss rates or
4199 with unreliable TFTP servers.
4201 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4202 unit, minimum value = 0). Defines how many timeouts
4203 can happen during a single file transfer before that
4204 transfer is aborted. The default is 10, and 0 means
4205 'no timeouts allowed'. Increasing this value may help
4206 downloads succeed with high packet loss rates, or with
4207 unreliable TFTP servers or client hardware.
4209 vlan - When set to a value < 4095 the traffic over
4210 Ethernet is encapsulated/received over 802.1q
4213 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4214 Unsigned value, in milliseconds. If not set, the period will
4215 be either the default (28000), or a value based on
4216 CONFIG_NET_RETRY_COUNT, if defined. This value has
4217 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4219 The following image location variables contain the location of images
4220 used in booting. The "Image" column gives the role of the image and is
4221 not an environment variable name. The other columns are environment
4222 variable names. "File Name" gives the name of the file on a TFTP
4223 server, "RAM Address" gives the location in RAM the image will be
4224 loaded to, and "Flash Location" gives the image's address in NOR
4225 flash or offset in NAND flash.
4227 *Note* - these variables don't have to be defined for all boards, some
4228 boards currently use other variables for these purposes, and some
4229 boards use these variables for other purposes.
4231 Image File Name RAM Address Flash Location
4232 ----- --------- ----------- --------------
4233 u-boot u-boot u-boot_addr_r u-boot_addr
4234 Linux kernel bootfile kernel_addr_r kernel_addr
4235 device tree blob fdtfile fdt_addr_r fdt_addr
4236 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4238 The following environment variables may be used and automatically
4239 updated by the network boot commands ("bootp" and "rarpboot"),
4240 depending the information provided by your boot server:
4242 bootfile - see above
4243 dnsip - IP address of your Domain Name Server
4244 dnsip2 - IP address of your secondary Domain Name Server
4245 gatewayip - IP address of the Gateway (Router) to use
4246 hostname - Target hostname
4248 netmask - Subnet Mask
4249 rootpath - Pathname of the root filesystem on the NFS server
4250 serverip - see above
4253 There are two special Environment Variables:
4255 serial# - contains hardware identification information such
4256 as type string and/or serial number
4257 ethaddr - Ethernet address
4259 These variables can be set only once (usually during manufacturing of
4260 the board). U-Boot refuses to delete or overwrite these variables
4261 once they have been set once.
4264 Further special Environment Variables:
4266 ver - Contains the U-Boot version string as printed
4267 with the "version" command. This variable is
4268 readonly (see CONFIG_VERSION_VARIABLE).
4271 Please note that changes to some configuration parameters may take
4272 only effect after the next boot (yes, that's just like Windoze :-).
4275 Callback functions for environment variables:
4276 ---------------------------------------------
4278 For some environment variables, the behavior of u-boot needs to change
4279 when their values are changed. This functionality allows functions to
4280 be associated with arbitrary variables. On creation, overwrite, or
4281 deletion, the callback will provide the opportunity for some side
4282 effect to happen or for the change to be rejected.
4284 The callbacks are named and associated with a function using the
4285 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4287 These callbacks are associated with variables in one of two ways. The
4288 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4289 in the board configuration to a string that defines a list of
4290 associations. The list must be in the following format:
4292 entry = variable_name[:callback_name]
4295 If the callback name is not specified, then the callback is deleted.
4296 Spaces are also allowed anywhere in the list.
4298 Callbacks can also be associated by defining the ".callbacks" variable
4299 with the same list format above. Any association in ".callbacks" will
4300 override any association in the static list. You can define
4301 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4302 ".callbacks" environment variable in the default or embedded environment.
4304 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4305 regular expression. This allows multiple variables to be connected to
4306 the same callback without explicitly listing them all out.
4309 Command Line Parsing:
4310 =====================
4312 There are two different command line parsers available with U-Boot:
4313 the old "simple" one, and the much more powerful "hush" shell:
4315 Old, simple command line parser:
4316 --------------------------------
4318 - supports environment variables (through setenv / saveenv commands)
4319 - several commands on one line, separated by ';'
4320 - variable substitution using "... ${name} ..." syntax
4321 - special characters ('$', ';') can be escaped by prefixing with '\',
4323 setenv bootcmd bootm \${address}
4324 - You can also escape text by enclosing in single apostrophes, for example:
4325 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4330 - similar to Bourne shell, with control structures like
4331 if...then...else...fi, for...do...done; while...do...done,
4332 until...do...done, ...
4333 - supports environment ("global") variables (through setenv / saveenv
4334 commands) and local shell variables (through standard shell syntax
4335 "name=value"); only environment variables can be used with "run"
4341 (1) If a command line (or an environment variable executed by a "run"
4342 command) contains several commands separated by semicolon, and
4343 one of these commands fails, then the remaining commands will be
4346 (2) If you execute several variables with one call to run (i. e.
4347 calling run with a list of variables as arguments), any failing
4348 command will cause "run" to terminate, i. e. the remaining
4349 variables are not executed.
4351 Note for Redundant Ethernet Interfaces:
4352 =======================================
4354 Some boards come with redundant Ethernet interfaces; U-Boot supports
4355 such configurations and is capable of automatic selection of a
4356 "working" interface when needed. MAC assignment works as follows:
4358 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4359 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4360 "eth1addr" (=>eth1), "eth2addr", ...
4362 If the network interface stores some valid MAC address (for instance
4363 in SROM), this is used as default address if there is NO correspon-
4364 ding setting in the environment; if the corresponding environment
4365 variable is set, this overrides the settings in the card; that means:
4367 o If the SROM has a valid MAC address, and there is no address in the
4368 environment, the SROM's address is used.
4370 o If there is no valid address in the SROM, and a definition in the
4371 environment exists, then the value from the environment variable is
4374 o If both the SROM and the environment contain a MAC address, and
4375 both addresses are the same, this MAC address is used.
4377 o If both the SROM and the environment contain a MAC address, and the
4378 addresses differ, the value from the environment is used and a
4381 o If neither SROM nor the environment contain a MAC address, an error
4382 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4383 a random, locally-assigned MAC is used.
4385 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4386 will be programmed into hardware as part of the initialization process. This
4387 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4388 The naming convention is as follows:
4389 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4394 U-Boot is capable of booting (and performing other auxiliary operations on)
4395 images in two formats:
4397 New uImage format (FIT)
4398 -----------------------
4400 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4401 to Flattened Device Tree). It allows the use of images with multiple
4402 components (several kernels, ramdisks, etc.), with contents protected by
4403 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4409 Old image format is based on binary files which can be basically anything,
4410 preceded by a special header; see the definitions in include/image.h for
4411 details; basically, the header defines the following image properties:
4413 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4414 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4415 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4416 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4418 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4419 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4420 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4421 * Compression Type (uncompressed, gzip, bzip2)
4427 The header is marked by a special Magic Number, and both the header
4428 and the data portions of the image are secured against corruption by
4435 Although U-Boot should support any OS or standalone application
4436 easily, the main focus has always been on Linux during the design of
4439 U-Boot includes many features that so far have been part of some
4440 special "boot loader" code within the Linux kernel. Also, any
4441 "initrd" images to be used are no longer part of one big Linux image;
4442 instead, kernel and "initrd" are separate images. This implementation
4443 serves several purposes:
4445 - the same features can be used for other OS or standalone
4446 applications (for instance: using compressed images to reduce the
4447 Flash memory footprint)
4449 - it becomes much easier to port new Linux kernel versions because
4450 lots of low-level, hardware dependent stuff are done by U-Boot
4452 - the same Linux kernel image can now be used with different "initrd"
4453 images; of course this also means that different kernel images can
4454 be run with the same "initrd". This makes testing easier (you don't
4455 have to build a new "zImage.initrd" Linux image when you just
4456 change a file in your "initrd"). Also, a field-upgrade of the
4457 software is easier now.
4463 Porting Linux to U-Boot based systems:
4464 ---------------------------------------
4466 U-Boot cannot save you from doing all the necessary modifications to
4467 configure the Linux device drivers for use with your target hardware
4468 (no, we don't intend to provide a full virtual machine interface to
4471 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4473 Just make sure your machine specific header file (for instance
4474 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4475 Information structure as we define in include/asm-<arch>/u-boot.h,
4476 and make sure that your definition of IMAP_ADDR uses the same value
4477 as your U-Boot configuration in CONFIG_SYS_IMMR.
4479 Note that U-Boot now has a driver model, a unified model for drivers.
4480 If you are adding a new driver, plumb it into driver model. If there
4481 is no uclass available, you are encouraged to create one. See
4485 Configuring the Linux kernel:
4486 -----------------------------
4488 No specific requirements for U-Boot. Make sure you have some root
4489 device (initial ramdisk, NFS) for your target system.
4492 Building a Linux Image:
4493 -----------------------
4495 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4496 not used. If you use recent kernel source, a new build target
4497 "uImage" will exist which automatically builds an image usable by
4498 U-Boot. Most older kernels also have support for a "pImage" target,
4499 which was introduced for our predecessor project PPCBoot and uses a
4500 100% compatible format.
4504 make TQM850L_defconfig
4509 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4510 encapsulate a compressed Linux kernel image with header information,
4511 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4513 * build a standard "vmlinux" kernel image (in ELF binary format):
4515 * convert the kernel into a raw binary image:
4517 ${CROSS_COMPILE}-objcopy -O binary \
4518 -R .note -R .comment \
4519 -S vmlinux linux.bin
4521 * compress the binary image:
4525 * package compressed binary image for U-Boot:
4527 mkimage -A ppc -O linux -T kernel -C gzip \
4528 -a 0 -e 0 -n "Linux Kernel Image" \
4529 -d linux.bin.gz uImage
4532 The "mkimage" tool can also be used to create ramdisk images for use
4533 with U-Boot, either separated from the Linux kernel image, or
4534 combined into one file. "mkimage" encapsulates the images with a 64
4535 byte header containing information about target architecture,
4536 operating system, image type, compression method, entry points, time
4537 stamp, CRC32 checksums, etc.
4539 "mkimage" can be called in two ways: to verify existing images and
4540 print the header information, or to build new images.
4542 In the first form (with "-l" option) mkimage lists the information
4543 contained in the header of an existing U-Boot image; this includes
4544 checksum verification:
4546 tools/mkimage -l image
4547 -l ==> list image header information
4549 The second form (with "-d" option) is used to build a U-Boot image
4550 from a "data file" which is used as image payload:
4552 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4553 -n name -d data_file image
4554 -A ==> set architecture to 'arch'
4555 -O ==> set operating system to 'os'
4556 -T ==> set image type to 'type'
4557 -C ==> set compression type 'comp'
4558 -a ==> set load address to 'addr' (hex)
4559 -e ==> set entry point to 'ep' (hex)
4560 -n ==> set image name to 'name'
4561 -d ==> use image data from 'datafile'
4563 Right now, all Linux kernels for PowerPC systems use the same load
4564 address (0x00000000), but the entry point address depends on the
4567 - 2.2.x kernels have the entry point at 0x0000000C,
4568 - 2.3.x and later kernels have the entry point at 0x00000000.
4570 So a typical call to build a U-Boot image would read:
4572 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4573 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4574 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4575 > examples/uImage.TQM850L
4576 Image Name: 2.4.4 kernel for TQM850L
4577 Created: Wed Jul 19 02:34:59 2000
4578 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4579 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4580 Load Address: 0x00000000
4581 Entry Point: 0x00000000
4583 To verify the contents of the image (or check for corruption):
4585 -> tools/mkimage -l examples/uImage.TQM850L
4586 Image Name: 2.4.4 kernel for TQM850L
4587 Created: Wed Jul 19 02:34:59 2000
4588 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4589 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4590 Load Address: 0x00000000
4591 Entry Point: 0x00000000
4593 NOTE: for embedded systems where boot time is critical you can trade
4594 speed for memory and install an UNCOMPRESSED image instead: this
4595 needs more space in Flash, but boots much faster since it does not
4596 need to be uncompressed:
4598 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4599 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4600 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4601 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4602 > examples/uImage.TQM850L-uncompressed
4603 Image Name: 2.4.4 kernel for TQM850L
4604 Created: Wed Jul 19 02:34:59 2000
4605 Image Type: PowerPC Linux Kernel Image (uncompressed)
4606 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4607 Load Address: 0x00000000
4608 Entry Point: 0x00000000
4611 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4612 when your kernel is intended to use an initial ramdisk:
4614 -> tools/mkimage -n 'Simple Ramdisk Image' \
4615 > -A ppc -O linux -T ramdisk -C gzip \
4616 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4617 Image Name: Simple Ramdisk Image
4618 Created: Wed Jan 12 14:01:50 2000
4619 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4620 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4621 Load Address: 0x00000000
4622 Entry Point: 0x00000000
4624 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4625 option performs the converse operation of the mkimage's second form (the "-d"
4626 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4629 tools/dumpimage -i image -T type -p position data_file
4630 -i ==> extract from the 'image' a specific 'data_file'
4631 -T ==> set image type to 'type'
4632 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4635 Installing a Linux Image:
4636 -------------------------
4638 To downloading a U-Boot image over the serial (console) interface,
4639 you must convert the image to S-Record format:
4641 objcopy -I binary -O srec examples/image examples/image.srec
4643 The 'objcopy' does not understand the information in the U-Boot
4644 image header, so the resulting S-Record file will be relative to
4645 address 0x00000000. To load it to a given address, you need to
4646 specify the target address as 'offset' parameter with the 'loads'
4649 Example: install the image to address 0x40100000 (which on the
4650 TQM8xxL is in the first Flash bank):
4652 => erase 40100000 401FFFFF
4658 ## Ready for S-Record download ...
4659 ~>examples/image.srec
4660 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4662 15989 15990 15991 15992
4663 [file transfer complete]
4665 ## Start Addr = 0x00000000
4668 You can check the success of the download using the 'iminfo' command;
4669 this includes a checksum verification so you can be sure no data
4670 corruption happened:
4674 ## Checking Image at 40100000 ...
4675 Image Name: 2.2.13 for initrd on TQM850L
4676 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4677 Data Size: 335725 Bytes = 327 kB = 0 MB
4678 Load Address: 00000000
4679 Entry Point: 0000000c
4680 Verifying Checksum ... OK
4686 The "bootm" command is used to boot an application that is stored in
4687 memory (RAM or Flash). In case of a Linux kernel image, the contents
4688 of the "bootargs" environment variable is passed to the kernel as
4689 parameters. You can check and modify this variable using the
4690 "printenv" and "setenv" commands:
4693 => printenv bootargs
4694 bootargs=root=/dev/ram
4696 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4698 => printenv bootargs
4699 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4702 ## Booting Linux kernel at 40020000 ...
4703 Image Name: 2.2.13 for NFS on TQM850L
4704 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4705 Data Size: 381681 Bytes = 372 kB = 0 MB
4706 Load Address: 00000000
4707 Entry Point: 0000000c
4708 Verifying Checksum ... OK
4709 Uncompressing Kernel Image ... OK
4710 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
4711 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4712 time_init: decrementer frequency = 187500000/60
4713 Calibrating delay loop... 49.77 BogoMIPS
4714 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4717 If you want to boot a Linux kernel with initial RAM disk, you pass
4718 the memory addresses of both the kernel and the initrd image (PPBCOOT
4719 format!) to the "bootm" command:
4721 => imi 40100000 40200000
4723 ## Checking Image at 40100000 ...
4724 Image Name: 2.2.13 for initrd on TQM850L
4725 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4726 Data Size: 335725 Bytes = 327 kB = 0 MB
4727 Load Address: 00000000
4728 Entry Point: 0000000c
4729 Verifying Checksum ... OK
4731 ## Checking Image at 40200000 ...
4732 Image Name: Simple Ramdisk Image
4733 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4734 Data Size: 566530 Bytes = 553 kB = 0 MB
4735 Load Address: 00000000
4736 Entry Point: 00000000
4737 Verifying Checksum ... OK
4739 => bootm 40100000 40200000
4740 ## Booting Linux kernel at 40100000 ...
4741 Image Name: 2.2.13 for initrd on TQM850L
4742 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4743 Data Size: 335725 Bytes = 327 kB = 0 MB
4744 Load Address: 00000000
4745 Entry Point: 0000000c
4746 Verifying Checksum ... OK
4747 Uncompressing Kernel Image ... OK
4748 ## Loading RAMDisk Image at 40200000 ...
4749 Image Name: Simple Ramdisk Image
4750 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4751 Data Size: 566530 Bytes = 553 kB = 0 MB
4752 Load Address: 00000000
4753 Entry Point: 00000000
4754 Verifying Checksum ... OK
4755 Loading Ramdisk ... OK
4756 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
4757 Boot arguments: root=/dev/ram
4758 time_init: decrementer frequency = 187500000/60
4759 Calibrating delay loop... 49.77 BogoMIPS
4761 RAMDISK: Compressed image found at block 0
4762 VFS: Mounted root (ext2 filesystem).
4766 Boot Linux and pass a flat device tree:
4769 First, U-Boot must be compiled with the appropriate defines. See the section
4770 titled "Linux Kernel Interface" above for a more in depth explanation. The
4771 following is an example of how to start a kernel and pass an updated
4777 oft=oftrees/mpc8540ads.dtb
4778 => tftp $oftaddr $oft
4779 Speed: 1000, full duplex
4781 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4782 Filename 'oftrees/mpc8540ads.dtb'.
4783 Load address: 0x300000
4786 Bytes transferred = 4106 (100a hex)
4787 => tftp $loadaddr $bootfile
4788 Speed: 1000, full duplex
4790 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4792 Load address: 0x200000
4793 Loading:############
4795 Bytes transferred = 1029407 (fb51f hex)
4800 => bootm $loadaddr - $oftaddr
4801 ## Booting image at 00200000 ...
4802 Image Name: Linux-2.6.17-dirty
4803 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4804 Data Size: 1029343 Bytes = 1005.2 kB
4805 Load Address: 00000000
4806 Entry Point: 00000000
4807 Verifying Checksum ... OK
4808 Uncompressing Kernel Image ... OK
4809 Booting using flat device tree at 0x300000
4810 Using MPC85xx ADS machine description
4811 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4815 More About U-Boot Image Types:
4816 ------------------------------
4818 U-Boot supports the following image types:
4820 "Standalone Programs" are directly runnable in the environment
4821 provided by U-Boot; it is expected that (if they behave
4822 well) you can continue to work in U-Boot after return from
4823 the Standalone Program.
4824 "OS Kernel Images" are usually images of some Embedded OS which
4825 will take over control completely. Usually these programs
4826 will install their own set of exception handlers, device
4827 drivers, set up the MMU, etc. - this means, that you cannot
4828 expect to re-enter U-Boot except by resetting the CPU.
4829 "RAMDisk Images" are more or less just data blocks, and their
4830 parameters (address, size) are passed to an OS kernel that is
4832 "Multi-File Images" contain several images, typically an OS
4833 (Linux) kernel image and one or more data images like
4834 RAMDisks. This construct is useful for instance when you want
4835 to boot over the network using BOOTP etc., where the boot
4836 server provides just a single image file, but you want to get
4837 for instance an OS kernel and a RAMDisk image.
4839 "Multi-File Images" start with a list of image sizes, each
4840 image size (in bytes) specified by an "uint32_t" in network
4841 byte order. This list is terminated by an "(uint32_t)0".
4842 Immediately after the terminating 0 follow the images, one by
4843 one, all aligned on "uint32_t" boundaries (size rounded up to
4844 a multiple of 4 bytes).
4846 "Firmware Images" are binary images containing firmware (like
4847 U-Boot or FPGA images) which usually will be programmed to
4850 "Script files" are command sequences that will be executed by
4851 U-Boot's command interpreter; this feature is especially
4852 useful when you configure U-Boot to use a real shell (hush)
4853 as command interpreter.
4855 Booting the Linux zImage:
4856 -------------------------
4858 On some platforms, it's possible to boot Linux zImage. This is done
4859 using the "bootz" command. The syntax of "bootz" command is the same
4860 as the syntax of "bootm" command.
4862 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4863 kernel with raw initrd images. The syntax is slightly different, the
4864 address of the initrd must be augmented by it's size, in the following
4865 format: "<initrd addres>:<initrd size>".
4871 One of the features of U-Boot is that you can dynamically load and
4872 run "standalone" applications, which can use some resources of
4873 U-Boot like console I/O functions or interrupt services.
4875 Two simple examples are included with the sources:
4880 'examples/hello_world.c' contains a small "Hello World" Demo
4881 application; it is automatically compiled when you build U-Boot.
4882 It's configured to run at address 0x00040004, so you can play with it
4886 ## Ready for S-Record download ...
4887 ~>examples/hello_world.srec
4888 1 2 3 4 5 6 7 8 9 10 11 ...
4889 [file transfer complete]
4891 ## Start Addr = 0x00040004
4893 => go 40004 Hello World! This is a test.
4894 ## Starting application at 0x00040004 ...
4905 Hit any key to exit ...
4907 ## Application terminated, rc = 0x0
4909 Another example, which demonstrates how to register a CPM interrupt
4910 handler with the U-Boot code, can be found in 'examples/timer.c'.
4911 Here, a CPM timer is set up to generate an interrupt every second.
4912 The interrupt service routine is trivial, just printing a '.'
4913 character, but this is just a demo program. The application can be
4914 controlled by the following keys:
4916 ? - print current values og the CPM Timer registers
4917 b - enable interrupts and start timer
4918 e - stop timer and disable interrupts
4919 q - quit application
4922 ## Ready for S-Record download ...
4923 ~>examples/timer.srec
4924 1 2 3 4 5 6 7 8 9 10 11 ...
4925 [file transfer complete]
4927 ## Start Addr = 0x00040004
4930 ## Starting application at 0x00040004 ...
4933 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4936 [q, b, e, ?] Set interval 1000000 us
4939 [q, b, e, ?] ........
4940 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4943 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4946 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4949 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4951 [q, b, e, ?] ...Stopping timer
4953 [q, b, e, ?] ## Application terminated, rc = 0x0
4959 Over time, many people have reported problems when trying to use the
4960 "minicom" terminal emulation program for serial download. I (wd)
4961 consider minicom to be broken, and recommend not to use it. Under
4962 Unix, I recommend to use C-Kermit for general purpose use (and
4963 especially for kermit binary protocol download ("loadb" command), and
4964 use "cu" for S-Record download ("loads" command). See
4965 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4966 for help with kermit.
4969 Nevertheless, if you absolutely want to use it try adding this
4970 configuration to your "File transfer protocols" section:
4972 Name Program Name U/D FullScr IO-Red. Multi
4973 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4974 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4980 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4981 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4983 Building requires a cross environment; it is known to work on
4984 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4985 need gmake since the Makefiles are not compatible with BSD make).
4986 Note that the cross-powerpc package does not install include files;
4987 attempting to build U-Boot will fail because <machine/ansi.h> is
4988 missing. This file has to be installed and patched manually:
4990 # cd /usr/pkg/cross/powerpc-netbsd/include
4992 # ln -s powerpc machine
4993 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4994 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4996 Native builds *don't* work due to incompatibilities between native
4997 and U-Boot include files.
4999 Booting assumes that (the first part of) the image booted is a
5000 stage-2 loader which in turn loads and then invokes the kernel
5001 proper. Loader sources will eventually appear in the NetBSD source
5002 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5003 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5006 Implementation Internals:
5007 =========================
5009 The following is not intended to be a complete description of every
5010 implementation detail. However, it should help to understand the
5011 inner workings of U-Boot and make it easier to port it to custom
5015 Initial Stack, Global Data:
5016 ---------------------------
5018 The implementation of U-Boot is complicated by the fact that U-Boot
5019 starts running out of ROM (flash memory), usually without access to
5020 system RAM (because the memory controller is not initialized yet).
5021 This means that we don't have writable Data or BSS segments, and BSS
5022 is not initialized as zero. To be able to get a C environment working
5023 at all, we have to allocate at least a minimal stack. Implementation
5024 options for this are defined and restricted by the CPU used: Some CPU
5025 models provide on-chip memory (like the IMMR area on MPC8xx and
5026 MPC826x processors), on others (parts of) the data cache can be
5027 locked as (mis-) used as memory, etc.
5029 Chris Hallinan posted a good summary of these issues to the
5030 U-Boot mailing list:
5032 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5033 From: "Chris Hallinan" <clh@net1plus.com>
5034 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5037 Correct me if I'm wrong, folks, but the way I understand it
5038 is this: Using DCACHE as initial RAM for Stack, etc, does not
5039 require any physical RAM backing up the cache. The cleverness
5040 is that the cache is being used as a temporary supply of
5041 necessary storage before the SDRAM controller is setup. It's
5042 beyond the scope of this list to explain the details, but you
5043 can see how this works by studying the cache architecture and
5044 operation in the architecture and processor-specific manuals.
5046 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5047 is another option for the system designer to use as an
5048 initial stack/RAM area prior to SDRAM being available. Either
5049 option should work for you. Using CS 4 should be fine if your
5050 board designers haven't used it for something that would
5051 cause you grief during the initial boot! It is frequently not
5054 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5055 with your processor/board/system design. The default value
5056 you will find in any recent u-boot distribution in
5057 walnut.h should work for you. I'd set it to a value larger
5058 than your SDRAM module. If you have a 64MB SDRAM module, set
5059 it above 400_0000. Just make sure your board has no resources
5060 that are supposed to respond to that address! That code in
5061 start.S has been around a while and should work as is when
5062 you get the config right.
5067 It is essential to remember this, since it has some impact on the C
5068 code for the initialization procedures:
5070 * Initialized global data (data segment) is read-only. Do not attempt
5073 * Do not use any uninitialized global data (or implicitly initialized
5074 as zero data - BSS segment) at all - this is undefined, initiali-
5075 zation is performed later (when relocating to RAM).
5077 * Stack space is very limited. Avoid big data buffers or things like
5080 Having only the stack as writable memory limits means we cannot use
5081 normal global data to share information between the code. But it
5082 turned out that the implementation of U-Boot can be greatly
5083 simplified by making a global data structure (gd_t) available to all
5084 functions. We could pass a pointer to this data as argument to _all_
5085 functions, but this would bloat the code. Instead we use a feature of
5086 the GCC compiler (Global Register Variables) to share the data: we
5087 place a pointer (gd) to the global data into a register which we
5088 reserve for this purpose.
5090 When choosing a register for such a purpose we are restricted by the
5091 relevant (E)ABI specifications for the current architecture, and by
5092 GCC's implementation.
5094 For PowerPC, the following registers have specific use:
5096 R2: reserved for system use
5097 R3-R4: parameter passing and return values
5098 R5-R10: parameter passing
5099 R13: small data area pointer
5103 (U-Boot also uses R12 as internal GOT pointer. r12
5104 is a volatile register so r12 needs to be reset when
5105 going back and forth between asm and C)
5107 ==> U-Boot will use R2 to hold a pointer to the global data
5109 Note: on PPC, we could use a static initializer (since the
5110 address of the global data structure is known at compile time),
5111 but it turned out that reserving a register results in somewhat
5112 smaller code - although the code savings are not that big (on
5113 average for all boards 752 bytes for the whole U-Boot image,
5114 624 text + 127 data).
5116 On ARM, the following registers are used:
5118 R0: function argument word/integer result
5119 R1-R3: function argument word
5120 R9: platform specific
5121 R10: stack limit (used only if stack checking is enabled)
5122 R11: argument (frame) pointer
5123 R12: temporary workspace
5126 R15: program counter
5128 ==> U-Boot will use R9 to hold a pointer to the global data
5130 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5132 On Nios II, the ABI is documented here:
5133 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5135 ==> U-Boot will use gp to hold a pointer to the global data
5137 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5138 to access small data sections, so gp is free.
5140 On NDS32, the following registers are used:
5142 R0-R1: argument/return
5144 R15: temporary register for assembler
5145 R16: trampoline register
5146 R28: frame pointer (FP)
5147 R29: global pointer (GP)
5148 R30: link register (LP)
5149 R31: stack pointer (SP)
5150 PC: program counter (PC)
5152 ==> U-Boot will use R10 to hold a pointer to the global data
5154 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5155 or current versions of GCC may "optimize" the code too much.
5160 U-Boot runs in system state and uses physical addresses, i.e. the
5161 MMU is not used either for address mapping nor for memory protection.
5163 The available memory is mapped to fixed addresses using the memory
5164 controller. In this process, a contiguous block is formed for each
5165 memory type (Flash, SDRAM, SRAM), even when it consists of several
5166 physical memory banks.
5168 U-Boot is installed in the first 128 kB of the first Flash bank (on
5169 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5170 booting and sizing and initializing DRAM, the code relocates itself
5171 to the upper end of DRAM. Immediately below the U-Boot code some
5172 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5173 configuration setting]. Below that, a structure with global Board
5174 Info data is placed, followed by the stack (growing downward).
5176 Additionally, some exception handler code is copied to the low 8 kB
5177 of DRAM (0x00000000 ... 0x00001FFF).
5179 So a typical memory configuration with 16 MB of DRAM could look like
5182 0x0000 0000 Exception Vector code
5185 0x0000 2000 Free for Application Use
5191 0x00FB FF20 Monitor Stack (Growing downward)
5192 0x00FB FFAC Board Info Data and permanent copy of global data
5193 0x00FC 0000 Malloc Arena
5196 0x00FE 0000 RAM Copy of Monitor Code
5197 ... eventually: LCD or video framebuffer
5198 ... eventually: pRAM (Protected RAM - unchanged by reset)
5199 0x00FF FFFF [End of RAM]
5202 System Initialization:
5203 ----------------------
5205 In the reset configuration, U-Boot starts at the reset entry point
5206 (on most PowerPC systems at address 0x00000100). Because of the reset
5207 configuration for CS0# this is a mirror of the on board Flash memory.
5208 To be able to re-map memory U-Boot then jumps to its link address.
5209 To be able to implement the initialization code in C, a (small!)
5210 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5211 which provide such a feature like), or in a locked part of the data
5212 cache. After that, U-Boot initializes the CPU core, the caches and
5215 Next, all (potentially) available memory banks are mapped using a
5216 preliminary mapping. For example, we put them on 512 MB boundaries
5217 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5218 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5219 programmed for SDRAM access. Using the temporary configuration, a
5220 simple memory test is run that determines the size of the SDRAM
5223 When there is more than one SDRAM bank, and the banks are of
5224 different size, the largest is mapped first. For equal size, the first
5225 bank (CS2#) is mapped first. The first mapping is always for address
5226 0x00000000, with any additional banks following immediately to create
5227 contiguous memory starting from 0.
5229 Then, the monitor installs itself at the upper end of the SDRAM area
5230 and allocates memory for use by malloc() and for the global Board
5231 Info data; also, the exception vector code is copied to the low RAM
5232 pages, and the final stack is set up.
5234 Only after this relocation will you have a "normal" C environment;
5235 until that you are restricted in several ways, mostly because you are
5236 running from ROM, and because the code will have to be relocated to a
5240 U-Boot Porting Guide:
5241 ----------------------
5243 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5247 int main(int argc, char *argv[])
5249 sighandler_t no_more_time;
5251 signal(SIGALRM, no_more_time);
5252 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5254 if (available_money > available_manpower) {
5255 Pay consultant to port U-Boot;
5259 Download latest U-Boot source;
5261 Subscribe to u-boot mailing list;
5264 email("Hi, I am new to U-Boot, how do I get started?");
5267 Read the README file in the top level directory;
5268 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5269 Read applicable doc/*.README;
5270 Read the source, Luke;
5271 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5274 if (available_money > toLocalCurrency ($2500))
5277 Add a lot of aggravation and time;
5279 if (a similar board exists) { /* hopefully... */
5280 cp -a board/<similar> board/<myboard>
5281 cp include/configs/<similar>.h include/configs/<myboard>.h
5283 Create your own board support subdirectory;
5284 Create your own board include/configs/<myboard>.h file;
5286 Edit new board/<myboard> files
5287 Edit new include/configs/<myboard>.h
5292 Add / modify source code;
5296 email("Hi, I am having problems...");
5298 Send patch file to the U-Boot email list;
5299 if (reasonable critiques)
5300 Incorporate improvements from email list code review;
5302 Defend code as written;
5308 void no_more_time (int sig)
5317 All contributions to U-Boot should conform to the Linux kernel
5318 coding style; see the file "Documentation/CodingStyle" and the script
5319 "scripts/Lindent" in your Linux kernel source directory.
5321 Source files originating from a different project (for example the
5322 MTD subsystem) are generally exempt from these guidelines and are not
5323 reformatted to ease subsequent migration to newer versions of those
5326 Please note that U-Boot is implemented in C (and to some small parts in
5327 Assembler); no C++ is used, so please do not use C++ style comments (//)
5330 Please also stick to the following formatting rules:
5331 - remove any trailing white space
5332 - use TAB characters for indentation and vertical alignment, not spaces
5333 - make sure NOT to use DOS '\r\n' line feeds
5334 - do not add more than 2 consecutive empty lines to source files
5335 - do not add trailing empty lines to source files
5337 Submissions which do not conform to the standards may be returned
5338 with a request to reformat the changes.
5344 Since the number of patches for U-Boot is growing, we need to
5345 establish some rules. Submissions which do not conform to these rules
5346 may be rejected, even when they contain important and valuable stuff.
5348 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5350 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5351 see http://lists.denx.de/mailman/listinfo/u-boot
5353 When you send a patch, please include the following information with
5356 * For bug fixes: a description of the bug and how your patch fixes
5357 this bug. Please try to include a way of demonstrating that the
5358 patch actually fixes something.
5360 * For new features: a description of the feature and your
5363 * A CHANGELOG entry as plaintext (separate from the patch)
5365 * For major contributions, add a MAINTAINERS file with your
5366 information and associated file and directory references.
5368 * When you add support for a new board, don't forget to add a
5369 maintainer e-mail address to the boards.cfg file, too.
5371 * If your patch adds new configuration options, don't forget to
5372 document these in the README file.
5374 * The patch itself. If you are using git (which is *strongly*
5375 recommended) you can easily generate the patch using the
5376 "git format-patch". If you then use "git send-email" to send it to
5377 the U-Boot mailing list, you will avoid most of the common problems
5378 with some other mail clients.
5380 If you cannot use git, use "diff -purN OLD NEW". If your version of
5381 diff does not support these options, then get the latest version of
5384 The current directory when running this command shall be the parent
5385 directory of the U-Boot source tree (i. e. please make sure that
5386 your patch includes sufficient directory information for the
5389 We prefer patches as plain text. MIME attachments are discouraged,
5390 and compressed attachments must not be used.
5392 * If one logical set of modifications affects or creates several
5393 files, all these changes shall be submitted in a SINGLE patch file.
5395 * Changesets that contain different, unrelated modifications shall be
5396 submitted as SEPARATE patches, one patch per changeset.
5401 * Before sending the patch, run the buildman script on your patched
5402 source tree and make sure that no errors or warnings are reported
5403 for any of the boards.
5405 * Keep your modifications to the necessary minimum: A patch
5406 containing several unrelated changes or arbitrary reformats will be
5407 returned with a request to re-formatting / split it.
5409 * If you modify existing code, make sure that your new code does not
5410 add to the memory footprint of the code ;-) Small is beautiful!
5411 When adding new features, these should compile conditionally only
5412 (using #ifdef), and the resulting code with the new feature
5413 disabled must not need more memory than the old code without your
5416 * Remember that there is a size limit of 100 kB per message on the
5417 u-boot mailing list. Bigger patches will be moderated. If they are
5418 reasonable and not too big, they will be acknowledged. But patches
5419 bigger than the size limit should be avoided.