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 Depending on board, define exactly one serial port
692 (CONFIG_8xx_CONS_SMC1 or CONFIG_8xx_CONS_SMC2),
693 or switch off the serial console by defining
696 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
697 port routines must be defined elsewhere
698 (i.e. serial_init(), serial_getc(), ...)
701 CONFIG_BAUDRATE - in bps
702 Select one of the baudrates listed in
703 CONFIG_SYS_BAUDRATE_TABLE, see below.
704 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
706 - Console Rx buffer length
707 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
708 the maximum receive buffer length for the SMC.
709 This option is actual only for 8xx possible.
710 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
711 must be defined, to setup the maximum idle timeout for
716 Only needed when CONFIG_BOOTDELAY is enabled;
717 define a command string that is automatically executed
718 when no character is read on the console interface
719 within "Boot Delay" after reset.
722 This can be used to pass arguments to the bootm
723 command. The value of CONFIG_BOOTARGS goes into the
724 environment value "bootargs".
726 CONFIG_RAMBOOT and CONFIG_NFSBOOT
727 The value of these goes into the environment as
728 "ramboot" and "nfsboot" respectively, and can be used
729 as a convenience, when switching between booting from
733 CONFIG_BOOTCOUNT_LIMIT
734 Implements a mechanism for detecting a repeating reboot
736 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
739 If no softreset save registers are found on the hardware
740 "bootcount" is stored in the environment. To prevent a
741 saveenv on all reboots, the environment variable
742 "upgrade_available" is used. If "upgrade_available" is
743 0, "bootcount" is always 0, if "upgrade_available" is
744 1 "bootcount" is incremented in the environment.
745 So the Userspace Applikation must set the "upgrade_available"
746 and "bootcount" variable to 0, if a boot was successfully.
751 When this option is #defined, the existence of the
752 environment variable "preboot" will be checked
753 immediately before starting the CONFIG_BOOTDELAY
754 countdown and/or running the auto-boot command resp.
755 entering interactive mode.
757 This feature is especially useful when "preboot" is
758 automatically generated or modified. For an example
759 see the LWMON board specific code: here "preboot" is
760 modified when the user holds down a certain
761 combination of keys on the (special) keyboard when
764 - Serial Download Echo Mode:
766 If defined to 1, all characters received during a
767 serial download (using the "loads" command) are
768 echoed back. This might be needed by some terminal
769 emulations (like "cu"), but may as well just take
770 time on others. This setting #define's the initial
771 value of the "loads_echo" environment variable.
773 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
775 Select one of the baudrates listed in
776 CONFIG_SYS_BAUDRATE_TABLE, see below.
779 Monitor commands can be included or excluded
780 from the build by using the #include files
781 <config_cmd_all.h> and #undef'ing unwanted
782 commands, or adding #define's for wanted commands.
784 The default command configuration includes all commands
785 except those marked below with a "*".
787 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
788 CONFIG_CMD_ASKENV * ask for env variable
789 CONFIG_CMD_BDI bdinfo
790 CONFIG_CMD_BOOTD bootd
791 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
792 CONFIG_CMD_CACHE * icache, dcache
793 CONFIG_CMD_CONSOLE coninfo
794 CONFIG_CMD_DHCP * DHCP support
795 CONFIG_CMD_DIAG * Diagnostics
796 CONFIG_CMD_ECHO echo arguments
797 CONFIG_CMD_EDITENV edit env variable
798 CONFIG_CMD_ELF * bootelf, bootvx
799 CONFIG_CMD_ENV_EXISTS * check existence of env variable
800 CONFIG_CMD_EXPORTENV * export the environment
801 CONFIG_CMD_EXT2 * ext2 command support
802 CONFIG_CMD_EXT4 * ext4 command support
803 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
804 that work for multiple fs types
805 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
806 CONFIG_CMD_SAVEENV saveenv
807 CONFIG_CMD_FLASH flinfo, erase, protect
808 CONFIG_CMD_FPGA FPGA device initialization support
809 CONFIG_CMD_GO * the 'go' command (exec code)
810 CONFIG_CMD_GREPENV * search environment
811 CONFIG_CMD_I2C * I2C serial bus support
812 CONFIG_CMD_IMI iminfo
813 CONFIG_CMD_IMLS List all images found in NOR flash
814 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
815 CONFIG_CMD_IMPORTENV * import an environment
816 CONFIG_CMD_INI * import data from an ini file into the env
817 CONFIG_CMD_ITEST Integer/string test of 2 values
818 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
819 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
821 CONFIG_CMD_LOADB loadb
822 CONFIG_CMD_LOADS loads
823 CONFIG_CMD_MD5SUM * print md5 message digest
824 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
825 CONFIG_CMD_MEMINFO * Display detailed memory information
826 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
828 CONFIG_CMD_MEMTEST * mtest
829 CONFIG_CMD_MISC Misc functions like sleep etc
830 CONFIG_CMD_MMC * MMC memory mapped support
831 CONFIG_CMD_MII * MII utility commands
832 CONFIG_CMD_MTDPARTS * MTD partition support
833 CONFIG_CMD_NAND * NAND support
834 CONFIG_CMD_NET bootp, tftpboot, rarpboot
835 CONFIG_CMD_NFS NFS support
836 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
837 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
838 CONFIG_CMD_PCI * pciinfo
839 CONFIG_CMD_PCMCIA * PCMCIA support
840 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
842 CONFIG_CMD_PORTIO * Port I/O
843 CONFIG_CMD_READ * Read raw data from partition
844 CONFIG_CMD_REGINFO * Register dump
845 CONFIG_CMD_RUN run command in env variable
846 CONFIG_CMD_SANDBOX * sb command to access sandbox features
847 CONFIG_CMD_SAVES * save S record dump
848 CONFIG_SCSI * SCSI Support
849 CONFIG_CMD_SDRAM * print SDRAM configuration information
850 (requires CONFIG_CMD_I2C)
851 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
852 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
853 CONFIG_CMD_SOURCE "source" command Support
854 CONFIG_CMD_SPI * SPI serial bus support
855 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
856 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
857 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
858 CONFIG_CMD_TIMER * access to the system tick timer
859 CONFIG_CMD_USB * USB support
860 CONFIG_CMD_CDP * Cisco Discover Protocol support
861 CONFIG_CMD_MFSL * Microblaze FSL support
862 CONFIG_CMD_XIMG Load part of Multi Image
863 CONFIG_CMD_UUID * Generate random UUID or GUID string
865 EXAMPLE: If you want all functions except of network
866 support you can write:
868 #include "config_cmd_all.h"
869 #undef CONFIG_CMD_NET
872 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
874 Note: Don't enable the "icache" and "dcache" commands
875 (configuration option CONFIG_CMD_CACHE) unless you know
876 what you (and your U-Boot users) are doing. Data
877 cache cannot be enabled on systems like the
878 8xx (where accesses to the IMMR region must be
879 uncached), and it cannot be disabled on all other
880 systems where we (mis-) use the data cache to hold an
881 initial stack and some data.
884 XXX - this list needs to get updated!
886 - Removal of commands
887 If no commands are needed to boot, you can disable
888 CONFIG_CMDLINE to remove them. In this case, the command line
889 will not be available, and when U-Boot wants to execute the
890 boot command (on start-up) it will call board_run_command()
891 instead. This can reduce image size significantly for very
892 simple boot procedures.
894 - Regular expression support:
896 If this variable is defined, U-Boot is linked against
897 the SLRE (Super Light Regular Expression) library,
898 which adds regex support to some commands, as for
899 example "env grep" and "setexpr".
903 If this variable is defined, U-Boot will use a device tree
904 to configure its devices, instead of relying on statically
905 compiled #defines in the board file. This option is
906 experimental and only available on a few boards. The device
907 tree is available in the global data as gd->fdt_blob.
909 U-Boot needs to get its device tree from somewhere. This can
910 be done using one of the three options below:
913 If this variable is defined, U-Boot will embed a device tree
914 binary in its image. This device tree file should be in the
915 board directory and called <soc>-<board>.dts. The binary file
916 is then picked up in board_init_f() and made available through
917 the global data structure as gd->blob.
920 If this variable is defined, U-Boot will build a device tree
921 binary. It will be called u-boot.dtb. Architecture-specific
922 code will locate it at run-time. Generally this works by:
924 cat u-boot.bin u-boot.dtb >image.bin
926 and in fact, U-Boot does this for you, creating a file called
927 u-boot-dtb.bin which is useful in the common case. You can
928 still use the individual files if you need something more
932 If this variable is defined, U-Boot will use the device tree
933 provided by the board at runtime instead of embedding one with
934 the image. Only boards defining board_fdt_blob_setup() support
935 this option (see include/fdtdec.h file).
939 If this variable is defined, it enables watchdog
940 support for the SoC. There must be support in the SoC
941 specific code for a watchdog. For the 8xx
942 CPUs, the SIU Watchdog feature is enabled in the SYPCR
943 register. When supported for a specific SoC is
944 available, then no further board specific code should
948 When using a watchdog circuitry external to the used
949 SoC, then define this variable and provide board
950 specific code for the "hw_watchdog_reset" function.
952 CONFIG_AT91_HW_WDT_TIMEOUT
953 specify the timeout in seconds. default 2 seconds.
956 CONFIG_VERSION_VARIABLE
957 If this variable is defined, an environment variable
958 named "ver" is created by U-Boot showing the U-Boot
959 version as printed by the "version" command.
960 Any change to this variable will be reverted at the
965 When CONFIG_CMD_DATE is selected, the type of the RTC
966 has to be selected, too. Define exactly one of the
969 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
970 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
971 CONFIG_RTC_MC146818 - use MC146818 RTC
972 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
973 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
974 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
975 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
976 CONFIG_RTC_DS164x - use Dallas DS164x RTC
977 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
978 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
979 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
980 CONFIG_SYS_RV3029_TCR - enable trickle charger on
983 Note that if the RTC uses I2C, then the I2C interface
984 must also be configured. See I2C Support, below.
987 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
989 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
990 chip-ngpio pairs that tell the PCA953X driver the number of
991 pins supported by a particular chip.
993 Note that if the GPIO device uses I2C, then the I2C interface
994 must also be configured. See I2C Support, below.
997 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
998 accesses and can checksum them or write a list of them out
999 to memory. See the 'iotrace' command for details. This is
1000 useful for testing device drivers since it can confirm that
1001 the driver behaves the same way before and after a code
1002 change. Currently this is supported on sandbox and arm. To
1003 add support for your architecture, add '#include <iotrace.h>'
1004 to the bottom of arch/<arch>/include/asm/io.h and test.
1006 Example output from the 'iotrace stats' command is below.
1007 Note that if the trace buffer is exhausted, the checksum will
1008 still continue to operate.
1011 Start: 10000000 (buffer start address)
1012 Size: 00010000 (buffer size)
1013 Offset: 00000120 (current buffer offset)
1014 Output: 10000120 (start + offset)
1015 Count: 00000018 (number of trace records)
1016 CRC32: 9526fb66 (CRC32 of all trace records)
1018 - Timestamp Support:
1020 When CONFIG_TIMESTAMP is selected, the timestamp
1021 (date and time) of an image is printed by image
1022 commands like bootm or iminfo. This option is
1023 automatically enabled when you select CONFIG_CMD_DATE .
1025 - Partition Labels (disklabels) Supported:
1026 Zero or more of the following:
1027 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1028 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1029 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1030 bootloader. Note 2TB partition limit; see
1032 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1034 If IDE or SCSI support is enabled (CONFIG_IDE or
1035 CONFIG_SCSI) you must configure support for at
1036 least one non-MTD partition type as well.
1039 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1040 board configurations files but used nowhere!
1042 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1043 be performed by calling the function
1044 ide_set_reset(int reset)
1045 which has to be defined in a board specific file
1050 Set this to enable ATAPI support.
1055 Set this to enable support for disks larger than 137GB
1056 Also look at CONFIG_SYS_64BIT_LBA.
1057 Whithout these , LBA48 support uses 32bit variables and will 'only'
1058 support disks up to 2.1TB.
1060 CONFIG_SYS_64BIT_LBA:
1061 When enabled, makes the IDE subsystem use 64bit sector addresses.
1065 At the moment only there is only support for the
1066 SYM53C8XX SCSI controller; define
1067 CONFIG_SCSI_SYM53C8XX to enable it.
1069 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1070 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1071 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1072 maximum numbers of LUNs, SCSI ID's and target
1074 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1076 The environment variable 'scsidevs' is set to the number of
1077 SCSI devices found during the last scan.
1079 - NETWORK Support (PCI):
1081 Support for Intel 8254x/8257x gigabit chips.
1084 Utility code for direct access to the SPI bus on Intel 8257x.
1085 This does not do anything useful unless you set at least one
1086 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1088 CONFIG_E1000_SPI_GENERIC
1089 Allow generic access to the SPI bus on the Intel 8257x, for
1090 example with the "sspi" command.
1093 Management command for E1000 devices. When used on devices
1094 with SPI support you can reprogram the EEPROM from U-Boot.
1097 Support for Intel 82557/82559/82559ER chips.
1098 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1099 write routine for first time initialisation.
1102 Support for Digital 2114x chips.
1103 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1104 modem chip initialisation (KS8761/QS6611).
1107 Support for National dp83815 chips.
1110 Support for National dp8382[01] gigabit chips.
1112 - NETWORK Support (other):
1114 CONFIG_DRIVER_AT91EMAC
1115 Support for AT91RM9200 EMAC.
1118 Define this to use reduced MII inteface
1120 CONFIG_DRIVER_AT91EMAC_QUIET
1121 If this defined, the driver is quiet.
1122 The driver doen't show link status messages.
1124 CONFIG_CALXEDA_XGMAC
1125 Support for the Calxeda XGMAC device
1128 Support for SMSC's LAN91C96 chips.
1130 CONFIG_LAN91C96_USE_32_BIT
1131 Define this to enable 32 bit addressing
1134 Support for SMSC's LAN91C111 chip
1136 CONFIG_SMC91111_BASE
1137 Define this to hold the physical address
1138 of the device (I/O space)
1140 CONFIG_SMC_USE_32_BIT
1141 Define this if data bus is 32 bits
1143 CONFIG_SMC_USE_IOFUNCS
1144 Define this to use i/o functions instead of macros
1145 (some hardware wont work with macros)
1147 CONFIG_DRIVER_TI_EMAC
1148 Support for davinci emac
1150 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1151 Define this if you have more then 3 PHYs.
1154 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1156 CONFIG_FTGMAC100_EGIGA
1157 Define this to use GE link update with gigabit PHY.
1158 Define this if FTGMAC100 is connected to gigabit PHY.
1159 If your system has 10/100 PHY only, it might not occur
1160 wrong behavior. Because PHY usually return timeout or
1161 useless data when polling gigabit status and gigabit
1162 control registers. This behavior won't affect the
1163 correctnessof 10/100 link speed update.
1166 Support for SMSC's LAN911x and LAN921x chips
1169 Define this to hold the physical address
1170 of the device (I/O space)
1172 CONFIG_SMC911X_32_BIT
1173 Define this if data bus is 32 bits
1175 CONFIG_SMC911X_16_BIT
1176 Define this if data bus is 16 bits. If your processor
1177 automatically converts one 32 bit word to two 16 bit
1178 words you may also try CONFIG_SMC911X_32_BIT.
1181 Support for Renesas on-chip Ethernet controller
1183 CONFIG_SH_ETHER_USE_PORT
1184 Define the number of ports to be used
1186 CONFIG_SH_ETHER_PHY_ADDR
1187 Define the ETH PHY's address
1189 CONFIG_SH_ETHER_CACHE_WRITEBACK
1190 If this option is set, the driver enables cache flush.
1194 Support for PWM module on the imx6.
1198 Support TPM devices.
1200 CONFIG_TPM_TIS_INFINEON
1201 Support for Infineon i2c bus TPM devices. Only one device
1202 per system is supported at this time.
1204 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1205 Define the burst count bytes upper limit
1208 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1210 CONFIG_TPM_ST33ZP24_I2C
1211 Support for STMicroelectronics ST33ZP24 I2C devices.
1212 Requires TPM_ST33ZP24 and I2C.
1214 CONFIG_TPM_ST33ZP24_SPI
1215 Support for STMicroelectronics ST33ZP24 SPI devices.
1216 Requires TPM_ST33ZP24 and SPI.
1218 CONFIG_TPM_ATMEL_TWI
1219 Support for Atmel TWI TPM device. Requires I2C support.
1222 Support for generic parallel port TPM devices. Only one device
1223 per system is supported at this time.
1225 CONFIG_TPM_TIS_BASE_ADDRESS
1226 Base address where the generic TPM device is mapped
1227 to. Contemporary x86 systems usually map it at
1231 Add tpm monitor functions.
1232 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1233 provides monitor access to authorized functions.
1236 Define this to enable the TPM support library which provides
1237 functional interfaces to some TPM commands.
1238 Requires support for a TPM device.
1240 CONFIG_TPM_AUTH_SESSIONS
1241 Define this to enable authorized functions in the TPM library.
1242 Requires CONFIG_TPM and CONFIG_SHA1.
1245 At the moment only the UHCI host controller is
1246 supported (PIP405, MIP405); define
1247 CONFIG_USB_UHCI to enable it.
1248 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1249 and define CONFIG_USB_STORAGE to enable the USB
1252 Supported are USB Keyboards and USB Floppy drives
1255 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1256 txfilltuning field in the EHCI controller on reset.
1258 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1259 HW module registers.
1262 Define the below if you wish to use the USB console.
1263 Once firmware is rebuilt from a serial console issue the
1264 command "setenv stdin usbtty; setenv stdout usbtty" and
1265 attach your USB cable. The Unix command "dmesg" should print
1266 it has found a new device. The environment variable usbtty
1267 can be set to gserial or cdc_acm to enable your device to
1268 appear to a USB host as a Linux gserial device or a
1269 Common Device Class Abstract Control Model serial device.
1270 If you select usbtty = gserial you should be able to enumerate
1272 # modprobe usbserial vendor=0xVendorID product=0xProductID
1273 else if using cdc_acm, simply setting the environment
1274 variable usbtty to be cdc_acm should suffice. The following
1275 might be defined in YourBoardName.h
1278 Define this to build a UDC device
1281 Define this to have a tty type of device available to
1282 talk to the UDC device
1285 Define this to enable the high speed support for usb
1286 device and usbtty. If this feature is enabled, a routine
1287 int is_usbd_high_speed(void)
1288 also needs to be defined by the driver to dynamically poll
1289 whether the enumeration has succeded at high speed or full
1292 CONFIG_SYS_CONSOLE_IS_IN_ENV
1293 Define this if you want stdin, stdout &/or stderr to
1296 If you have a USB-IF assigned VendorID then you may wish to
1297 define your own vendor specific values either in BoardName.h
1298 or directly in usbd_vendor_info.h. If you don't define
1299 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1300 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1301 should pretend to be a Linux device to it's target host.
1303 CONFIG_USBD_MANUFACTURER
1304 Define this string as the name of your company for
1305 - CONFIG_USBD_MANUFACTURER "my company"
1307 CONFIG_USBD_PRODUCT_NAME
1308 Define this string as the name of your product
1309 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1311 CONFIG_USBD_VENDORID
1312 Define this as your assigned Vendor ID from the USB
1313 Implementors Forum. This *must* be a genuine Vendor ID
1314 to avoid polluting the USB namespace.
1315 - CONFIG_USBD_VENDORID 0xFFFF
1317 CONFIG_USBD_PRODUCTID
1318 Define this as the unique Product ID
1320 - CONFIG_USBD_PRODUCTID 0xFFFF
1322 - ULPI Layer Support:
1323 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1324 the generic ULPI layer. The generic layer accesses the ULPI PHY
1325 via the platform viewport, so you need both the genric layer and
1326 the viewport enabled. Currently only Chipidea/ARC based
1327 viewport is supported.
1328 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1329 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1330 If your ULPI phy needs a different reference clock than the
1331 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1332 the appropriate value in Hz.
1335 The MMC controller on the Intel PXA is supported. To
1336 enable this define CONFIG_MMC. The MMC can be
1337 accessed from the boot prompt by mapping the device
1338 to physical memory similar to flash. Command line is
1339 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1340 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1343 Support for Renesas on-chip MMCIF controller
1345 CONFIG_SH_MMCIF_ADDR
1346 Define the base address of MMCIF registers
1349 Define the clock frequency for MMCIF
1351 CONFIG_SUPPORT_EMMC_BOOT
1352 Enable some additional features of the eMMC boot partitions.
1354 CONFIG_SUPPORT_EMMC_RPMB
1355 Enable the commands for reading, writing and programming the
1356 key for the Replay Protection Memory Block partition in eMMC.
1358 - USB Device Firmware Update (DFU) class support:
1359 CONFIG_USB_FUNCTION_DFU
1360 This enables the USB portion of the DFU USB class
1363 This enables the command "dfu" which is used to have
1364 U-Boot create a DFU class device via USB. This command
1365 requires that the "dfu_alt_info" environment variable be
1366 set and define the alt settings to expose to the host.
1369 This enables support for exposing (e)MMC devices via DFU.
1372 This enables support for exposing NAND devices via DFU.
1375 This enables support for exposing RAM via DFU.
1376 Note: DFU spec refer to non-volatile memory usage, but
1377 allow usages beyond the scope of spec - here RAM usage,
1378 one that would help mostly the developer.
1380 CONFIG_SYS_DFU_DATA_BUF_SIZE
1381 Dfu transfer uses a buffer before writing data to the
1382 raw storage device. Make the size (in bytes) of this buffer
1383 configurable. The size of this buffer is also configurable
1384 through the "dfu_bufsiz" environment variable.
1386 CONFIG_SYS_DFU_MAX_FILE_SIZE
1387 When updating files rather than the raw storage device,
1388 we use a static buffer to copy the file into and then write
1389 the buffer once we've been given the whole file. Define
1390 this to the maximum filesize (in bytes) for the buffer.
1391 Default is 4 MiB if undefined.
1393 DFU_DEFAULT_POLL_TIMEOUT
1394 Poll timeout [ms], is the timeout a device can send to the
1395 host. The host must wait for this timeout before sending
1396 a subsequent DFU_GET_STATUS request to the device.
1398 DFU_MANIFEST_POLL_TIMEOUT
1399 Poll timeout [ms], which the device sends to the host when
1400 entering dfuMANIFEST state. Host waits this timeout, before
1401 sending again an USB request to the device.
1403 - USB Device Android Fastboot support:
1404 CONFIG_USB_FUNCTION_FASTBOOT
1405 This enables the USB part of the fastboot gadget
1408 This enables the command "fastboot" which enables the Android
1409 fastboot mode for the platform's USB device. Fastboot is a USB
1410 protocol for downloading images, flashing and device control
1411 used on Android devices.
1412 See doc/README.android-fastboot for more information.
1414 CONFIG_ANDROID_BOOT_IMAGE
1415 This enables support for booting images which use the Android
1416 image format header.
1418 CONFIG_FASTBOOT_BUF_ADDR
1419 The fastboot protocol requires a large memory buffer for
1420 downloads. Define this to the starting RAM address to use for
1423 CONFIG_FASTBOOT_BUF_SIZE
1424 The fastboot protocol requires a large memory buffer for
1425 downloads. This buffer should be as large as possible for a
1426 platform. Define this to the size available RAM for fastboot.
1428 CONFIG_FASTBOOT_FLASH
1429 The fastboot protocol includes a "flash" command for writing
1430 the downloaded image to a non-volatile storage device. Define
1431 this to enable the "fastboot flash" command.
1433 CONFIG_FASTBOOT_FLASH_MMC_DEV
1434 The fastboot "flash" command requires additional information
1435 regarding the non-volatile storage device. Define this to
1436 the eMMC device that fastboot should use to store the image.
1438 CONFIG_FASTBOOT_GPT_NAME
1439 The fastboot "flash" command supports writing the downloaded
1440 image to the Protective MBR and the Primary GUID Partition
1441 Table. (Additionally, this downloaded image is post-processed
1442 to generate and write the Backup GUID Partition Table.)
1443 This occurs when the specified "partition name" on the
1444 "fastboot flash" command line matches this value.
1445 The default is "gpt" if undefined.
1447 CONFIG_FASTBOOT_MBR_NAME
1448 The fastboot "flash" command supports writing the downloaded
1450 This occurs when the "partition name" specified on the
1451 "fastboot flash" command line matches this value.
1452 If not defined the default value "mbr" is used.
1454 - Journaling Flash filesystem support:
1456 Define these for a default partition on a NAND device
1458 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1459 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1460 Define these for a default partition on a NOR device
1463 See Kconfig help for available keyboard drivers.
1467 Define this to enable a custom keyboard support.
1468 This simply calls drv_keyboard_init() which must be
1469 defined in your board-specific files. This option is deprecated
1470 and is only used by novena. For new boards, use driver model
1475 Enable the Freescale DIU video driver. Reference boards for
1476 SOCs that have a DIU should define this macro to enable DIU
1477 support, and should also define these other macros:
1482 CONFIG_VIDEO_SW_CURSOR
1483 CONFIG_VGA_AS_SINGLE_DEVICE
1485 CONFIG_VIDEO_BMP_LOGO
1487 The DIU driver will look for the 'video-mode' environment
1488 variable, and if defined, enable the DIU as a console during
1489 boot. See the documentation file doc/README.video for a
1490 description of this variable.
1492 - LCD Support: CONFIG_LCD
1494 Define this to enable LCD support (for output to LCD
1495 display); also select one of the supported displays
1496 by defining one of these:
1500 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1502 CONFIG_NEC_NL6448AC33:
1504 NEC NL6448AC33-18. Active, color, single scan.
1506 CONFIG_NEC_NL6448BC20
1508 NEC NL6448BC20-08. 6.5", 640x480.
1509 Active, color, single scan.
1511 CONFIG_NEC_NL6448BC33_54
1513 NEC NL6448BC33-54. 10.4", 640x480.
1514 Active, color, single scan.
1518 Sharp 320x240. Active, color, single scan.
1519 It isn't 16x9, and I am not sure what it is.
1521 CONFIG_SHARP_LQ64D341
1523 Sharp LQ64D341 display, 640x480.
1524 Active, color, single scan.
1528 HLD1045 display, 640x480.
1529 Active, color, single scan.
1533 Optrex CBL50840-2 NF-FW 99 22 M5
1535 Hitachi LMG6912RPFC-00T
1539 320x240. Black & white.
1541 CONFIG_LCD_ALIGNMENT
1543 Normally the LCD is page-aligned (typically 4KB). If this is
1544 defined then the LCD will be aligned to this value instead.
1545 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1546 here, since it is cheaper to change data cache settings on
1547 a per-section basis.
1552 Sometimes, for example if the display is mounted in portrait
1553 mode or even if it's mounted landscape but rotated by 180degree,
1554 we need to rotate our content of the display relative to the
1555 framebuffer, so that user can read the messages which are
1557 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1558 initialized with a given rotation from "vl_rot" out of
1559 "vidinfo_t" which is provided by the board specific code.
1560 The value for vl_rot is coded as following (matching to
1561 fbcon=rotate:<n> linux-kernel commandline):
1562 0 = no rotation respectively 0 degree
1563 1 = 90 degree rotation
1564 2 = 180 degree rotation
1565 3 = 270 degree rotation
1567 If CONFIG_LCD_ROTATION is not defined, the console will be
1568 initialized with 0degree rotation.
1572 Support drawing of RLE8-compressed bitmaps on the LCD.
1576 Enables an 'i2c edid' command which can read EDID
1577 information over I2C from an attached LCD display.
1579 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1581 If this option is set, the environment is checked for
1582 a variable "splashimage". If found, the usual display
1583 of logo, copyright and system information on the LCD
1584 is suppressed and the BMP image at the address
1585 specified in "splashimage" is loaded instead. The
1586 console is redirected to the "nulldev", too. This
1587 allows for a "silent" boot where a splash screen is
1588 loaded very quickly after power-on.
1590 CONFIG_SPLASHIMAGE_GUARD
1592 If this option is set, then U-Boot will prevent the environment
1593 variable "splashimage" from being set to a problematic address
1594 (see doc/README.displaying-bmps).
1595 This option is useful for targets where, due to alignment
1596 restrictions, an improperly aligned BMP image will cause a data
1597 abort. If you think you will not have problems with unaligned
1598 accesses (for example because your toolchain prevents them)
1599 there is no need to set this option.
1601 CONFIG_SPLASH_SCREEN_ALIGN
1603 If this option is set the splash image can be freely positioned
1604 on the screen. Environment variable "splashpos" specifies the
1605 position as "x,y". If a positive number is given it is used as
1606 number of pixel from left/top. If a negative number is given it
1607 is used as number of pixel from right/bottom. You can also
1608 specify 'm' for centering the image.
1611 setenv splashpos m,m
1612 => image at center of screen
1614 setenv splashpos 30,20
1615 => image at x = 30 and y = 20
1617 setenv splashpos -10,m
1618 => vertically centered image
1619 at x = dspWidth - bmpWidth - 9
1621 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1623 If this option is set, additionally to standard BMP
1624 images, gzipped BMP images can be displayed via the
1625 splashscreen support or the bmp command.
1627 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1629 If this option is set, 8-bit RLE compressed BMP images
1630 can be displayed via the splashscreen support or the
1633 - Compression support:
1636 Enabled by default to support gzip compressed images.
1640 If this option is set, support for bzip2 compressed
1641 images is included. If not, only uncompressed and gzip
1642 compressed images are supported.
1644 NOTE: the bzip2 algorithm requires a lot of RAM, so
1645 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1650 If this option is set, support for LZO compressed images
1656 The address of PHY on MII bus.
1658 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1660 The clock frequency of the MII bus
1664 If this option is set, support for speed/duplex
1665 detection of gigabit PHY is included.
1667 CONFIG_PHY_RESET_DELAY
1669 Some PHY like Intel LXT971A need extra delay after
1670 reset before any MII register access is possible.
1671 For such PHY, set this option to the usec delay
1672 required. (minimum 300usec for LXT971A)
1674 CONFIG_PHY_CMD_DELAY (ppc4xx)
1676 Some PHY like Intel LXT971A need extra delay after
1677 command issued before MII status register can be read
1682 Define a default value for the IP address to use for
1683 the default Ethernet interface, in case this is not
1684 determined through e.g. bootp.
1685 (Environment variable "ipaddr")
1687 - Server IP address:
1690 Defines a default value for the IP address of a TFTP
1691 server to contact when using the "tftboot" command.
1692 (Environment variable "serverip")
1694 CONFIG_KEEP_SERVERADDR
1696 Keeps the server's MAC address, in the env 'serveraddr'
1697 for passing to bootargs (like Linux's netconsole option)
1699 - Gateway IP address:
1702 Defines a default value for the IP address of the
1703 default router where packets to other networks are
1705 (Environment variable "gatewayip")
1710 Defines a default value for the subnet mask (or
1711 routing prefix) which is used to determine if an IP
1712 address belongs to the local subnet or needs to be
1713 forwarded through a router.
1714 (Environment variable "netmask")
1716 - Multicast TFTP Mode:
1719 Defines whether you want to support multicast TFTP as per
1720 rfc-2090; for example to work with atftp. Lets lots of targets
1721 tftp down the same boot image concurrently. Note: the Ethernet
1722 driver in use must provide a function: mcast() to join/leave a
1725 - BOOTP Recovery Mode:
1726 CONFIG_BOOTP_RANDOM_DELAY
1728 If you have many targets in a network that try to
1729 boot using BOOTP, you may want to avoid that all
1730 systems send out BOOTP requests at precisely the same
1731 moment (which would happen for instance at recovery
1732 from a power failure, when all systems will try to
1733 boot, thus flooding the BOOTP server. Defining
1734 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1735 inserted before sending out BOOTP requests. The
1736 following delays are inserted then:
1738 1st BOOTP request: delay 0 ... 1 sec
1739 2nd BOOTP request: delay 0 ... 2 sec
1740 3rd BOOTP request: delay 0 ... 4 sec
1742 BOOTP requests: delay 0 ... 8 sec
1744 CONFIG_BOOTP_ID_CACHE_SIZE
1746 BOOTP packets are uniquely identified using a 32-bit ID. The
1747 server will copy the ID from client requests to responses and
1748 U-Boot will use this to determine if it is the destination of
1749 an incoming response. Some servers will check that addresses
1750 aren't in use before handing them out (usually using an ARP
1751 ping) and therefore take up to a few hundred milliseconds to
1752 respond. Network congestion may also influence the time it
1753 takes for a response to make it back to the client. If that
1754 time is too long, U-Boot will retransmit requests. In order
1755 to allow earlier responses to still be accepted after these
1756 retransmissions, U-Boot's BOOTP client keeps a small cache of
1757 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1758 cache. The default is to keep IDs for up to four outstanding
1759 requests. Increasing this will allow U-Boot to accept offers
1760 from a BOOTP client in networks with unusually high latency.
1762 - DHCP Advanced Options:
1763 You can fine tune the DHCP functionality by defining
1764 CONFIG_BOOTP_* symbols:
1766 CONFIG_BOOTP_SUBNETMASK
1767 CONFIG_BOOTP_GATEWAY
1768 CONFIG_BOOTP_HOSTNAME
1769 CONFIG_BOOTP_NISDOMAIN
1770 CONFIG_BOOTP_BOOTPATH
1771 CONFIG_BOOTP_BOOTFILESIZE
1774 CONFIG_BOOTP_SEND_HOSTNAME
1775 CONFIG_BOOTP_NTPSERVER
1776 CONFIG_BOOTP_TIMEOFFSET
1777 CONFIG_BOOTP_VENDOREX
1778 CONFIG_BOOTP_MAY_FAIL
1780 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1781 environment variable, not the BOOTP server.
1783 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1784 after the configured retry count, the call will fail
1785 instead of starting over. This can be used to fail over
1786 to Link-local IP address configuration if the DHCP server
1789 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1790 serverip from a DHCP server, it is possible that more
1791 than one DNS serverip is offered to the client.
1792 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1793 serverip will be stored in the additional environment
1794 variable "dnsip2". The first DNS serverip is always
1795 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1798 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1799 to do a dynamic update of a DNS server. To do this, they
1800 need the hostname of the DHCP requester.
1801 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1802 of the "hostname" environment variable is passed as
1803 option 12 to the DHCP server.
1805 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1807 A 32bit value in microseconds for a delay between
1808 receiving a "DHCP Offer" and sending the "DHCP Request".
1809 This fixes a problem with certain DHCP servers that don't
1810 respond 100% of the time to a "DHCP request". E.g. On an
1811 AT91RM9200 processor running at 180MHz, this delay needed
1812 to be *at least* 15,000 usec before a Windows Server 2003
1813 DHCP server would reply 100% of the time. I recommend at
1814 least 50,000 usec to be safe. The alternative is to hope
1815 that one of the retries will be successful but note that
1816 the DHCP timeout and retry process takes a longer than
1819 - Link-local IP address negotiation:
1820 Negotiate with other link-local clients on the local network
1821 for an address that doesn't require explicit configuration.
1822 This is especially useful if a DHCP server cannot be guaranteed
1823 to exist in all environments that the device must operate.
1825 See doc/README.link-local for more information.
1828 CONFIG_CDP_DEVICE_ID
1830 The device id used in CDP trigger frames.
1832 CONFIG_CDP_DEVICE_ID_PREFIX
1834 A two character string which is prefixed to the MAC address
1839 A printf format string which contains the ascii name of
1840 the port. Normally is set to "eth%d" which sets
1841 eth0 for the first Ethernet, eth1 for the second etc.
1843 CONFIG_CDP_CAPABILITIES
1845 A 32bit integer which indicates the device capabilities;
1846 0x00000010 for a normal host which does not forwards.
1850 An ascii string containing the version of the software.
1854 An ascii string containing the name of the platform.
1858 A 32bit integer sent on the trigger.
1860 CONFIG_CDP_POWER_CONSUMPTION
1862 A 16bit integer containing the power consumption of the
1863 device in .1 of milliwatts.
1865 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1867 A byte containing the id of the VLAN.
1869 - Status LED: CONFIG_LED_STATUS
1871 Several configurations allow to display the current
1872 status using a LED. For instance, the LED will blink
1873 fast while running U-Boot code, stop blinking as
1874 soon as a reply to a BOOTP request was received, and
1875 start blinking slow once the Linux kernel is running
1876 (supported by a status LED driver in the Linux
1877 kernel). Defining CONFIG_LED_STATUS enables this
1882 CONFIG_LED_STATUS_GPIO
1883 The status LED can be connected to a GPIO pin.
1884 In such cases, the gpio_led driver can be used as a
1885 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1886 to include the gpio_led driver in the U-Boot binary.
1888 CONFIG_GPIO_LED_INVERTED_TABLE
1889 Some GPIO connected LEDs may have inverted polarity in which
1890 case the GPIO high value corresponds to LED off state and
1891 GPIO low value corresponds to LED on state.
1892 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1893 with a list of GPIO LEDs that have inverted polarity.
1895 - I2C Support: CONFIG_SYS_I2C
1897 This enable the NEW i2c subsystem, and will allow you to use
1898 i2c commands at the u-boot command line (as long as you set
1899 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1900 based realtime clock chips or other i2c devices. See
1901 common/cmd_i2c.c for a description of the command line
1904 ported i2c driver to the new framework:
1905 - drivers/i2c/soft_i2c.c:
1906 - activate first bus with CONFIG_SYS_I2C_SOFT define
1907 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1908 for defining speed and slave address
1909 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1910 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1911 for defining speed and slave address
1912 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1913 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1914 for defining speed and slave address
1915 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1916 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1917 for defining speed and slave address
1919 - drivers/i2c/fsl_i2c.c:
1920 - activate i2c driver with CONFIG_SYS_I2C_FSL
1921 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1922 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1923 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1925 - If your board supports a second fsl i2c bus, define
1926 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1927 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1928 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1931 - drivers/i2c/tegra_i2c.c:
1932 - activate this driver with CONFIG_SYS_I2C_TEGRA
1933 - This driver adds 4 i2c buses with a fix speed from
1934 100000 and the slave addr 0!
1936 - drivers/i2c/ppc4xx_i2c.c
1937 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1938 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1939 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1941 - drivers/i2c/i2c_mxc.c
1942 - activate this driver with CONFIG_SYS_I2C_MXC
1943 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1944 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1945 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1946 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1947 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1948 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1949 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1950 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1951 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1952 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1953 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1954 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1955 If those defines are not set, default value is 100000
1956 for speed, and 0 for slave.
1958 - drivers/i2c/rcar_i2c.c:
1959 - activate this driver with CONFIG_SYS_I2C_RCAR
1960 - This driver adds 4 i2c buses
1962 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1963 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1964 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1965 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1966 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1967 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1968 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1969 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1970 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1972 - drivers/i2c/sh_i2c.c:
1973 - activate this driver with CONFIG_SYS_I2C_SH
1974 - This driver adds from 2 to 5 i2c buses
1976 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1977 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1978 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1979 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1980 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1981 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1982 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1983 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1984 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1985 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1986 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1988 - drivers/i2c/omap24xx_i2c.c
1989 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1990 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1991 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1992 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1993 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1994 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1995 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1996 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1997 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1998 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1999 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2001 - drivers/i2c/zynq_i2c.c
2002 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2003 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2004 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2006 - drivers/i2c/s3c24x0_i2c.c:
2007 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2008 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2009 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2010 with a fix speed from 100000 and the slave addr 0!
2012 - drivers/i2c/ihs_i2c.c
2013 - activate this driver with CONFIG_SYS_I2C_IHS
2014 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2015 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2016 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2017 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2018 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2019 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2020 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2021 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2022 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2023 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2024 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2025 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2026 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2027 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2028 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2029 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2030 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2031 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2032 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2033 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2034 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2038 CONFIG_SYS_NUM_I2C_BUSES
2039 Hold the number of i2c buses you want to use.
2041 CONFIG_SYS_I2C_DIRECT_BUS
2042 define this, if you don't use i2c muxes on your hardware.
2043 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2046 CONFIG_SYS_I2C_MAX_HOPS
2047 define how many muxes are maximal consecutively connected
2048 on one i2c bus. If you not use i2c muxes, omit this
2051 CONFIG_SYS_I2C_BUSES
2052 hold a list of buses you want to use, only used if
2053 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2054 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2055 CONFIG_SYS_NUM_I2C_BUSES = 9:
2057 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2058 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2059 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2060 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2061 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2062 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2063 {1, {I2C_NULL_HOP}}, \
2064 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2065 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2069 bus 0 on adapter 0 without a mux
2070 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2071 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2072 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2073 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2074 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2075 bus 6 on adapter 1 without a mux
2076 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2077 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2079 If you do not have i2c muxes on your board, omit this define.
2081 - Legacy I2C Support:
2082 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2083 then the following macros need to be defined (examples are
2084 from include/configs/lwmon.h):
2088 (Optional). Any commands necessary to enable the I2C
2089 controller or configure ports.
2091 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2095 The code necessary to make the I2C data line active
2096 (driven). If the data line is open collector, this
2099 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2103 The code necessary to make the I2C data line tri-stated
2104 (inactive). If the data line is open collector, this
2107 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2111 Code that returns true if the I2C data line is high,
2114 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2118 If <bit> is true, sets the I2C data line high. If it
2119 is false, it clears it (low).
2121 eg: #define I2C_SDA(bit) \
2122 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2123 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2127 If <bit> is true, sets the I2C clock line high. If it
2128 is false, it clears it (low).
2130 eg: #define I2C_SCL(bit) \
2131 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2132 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2136 This delay is invoked four times per clock cycle so this
2137 controls the rate of data transfer. The data rate thus
2138 is 1 / (I2C_DELAY * 4). Often defined to be something
2141 #define I2C_DELAY udelay(2)
2143 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2145 If your arch supports the generic GPIO framework (asm/gpio.h),
2146 then you may alternatively define the two GPIOs that are to be
2147 used as SCL / SDA. Any of the previous I2C_xxx macros will
2148 have GPIO-based defaults assigned to them as appropriate.
2150 You should define these to the GPIO value as given directly to
2151 the generic GPIO functions.
2153 CONFIG_SYS_I2C_INIT_BOARD
2155 When a board is reset during an i2c bus transfer
2156 chips might think that the current transfer is still
2157 in progress. On some boards it is possible to access
2158 the i2c SCLK line directly, either by using the
2159 processor pin as a GPIO or by having a second pin
2160 connected to the bus. If this option is defined a
2161 custom i2c_init_board() routine in boards/xxx/board.c
2162 is run early in the boot sequence.
2164 CONFIG_I2C_MULTI_BUS
2166 This option allows the use of multiple I2C buses, each of which
2167 must have a controller. At any point in time, only one bus is
2168 active. To switch to a different bus, use the 'i2c dev' command.
2169 Note that bus numbering is zero-based.
2171 CONFIG_SYS_I2C_NOPROBES
2173 This option specifies a list of I2C devices that will be skipped
2174 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2175 is set, specify a list of bus-device pairs. Otherwise, specify
2176 a 1D array of device addresses
2179 #undef CONFIG_I2C_MULTI_BUS
2180 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2182 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2184 #define CONFIG_I2C_MULTI_BUS
2185 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2187 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2189 CONFIG_SYS_SPD_BUS_NUM
2191 If defined, then this indicates the I2C bus number for DDR SPD.
2192 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2194 CONFIG_SYS_RTC_BUS_NUM
2196 If defined, then this indicates the I2C bus number for the RTC.
2197 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2199 CONFIG_SOFT_I2C_READ_REPEATED_START
2201 defining this will force the i2c_read() function in
2202 the soft_i2c driver to perform an I2C repeated start
2203 between writing the address pointer and reading the
2204 data. If this define is omitted the default behaviour
2205 of doing a stop-start sequence will be used. Most I2C
2206 devices can use either method, but some require one or
2209 - SPI Support: CONFIG_SPI
2211 Enables SPI driver (so far only tested with
2212 SPI EEPROM, also an instance works with Crystal A/D and
2213 D/As on the SACSng board)
2217 Enables the driver for SPI controller on SuperH. Currently
2218 only SH7757 is supported.
2222 Enables a software (bit-bang) SPI driver rather than
2223 using hardware support. This is a general purpose
2224 driver that only requires three general I/O port pins
2225 (two outputs, one input) to function. If this is
2226 defined, the board configuration must define several
2227 SPI configuration items (port pins to use, etc). For
2228 an example, see include/configs/sacsng.h.
2232 Enables a hardware SPI driver for general-purpose reads
2233 and writes. As with CONFIG_SOFT_SPI, the board configuration
2234 must define a list of chip-select function pointers.
2235 Currently supported on some MPC8xxx processors. For an
2236 example, see include/configs/mpc8349emds.h.
2240 Enables the driver for the SPI controllers on i.MX and MXC
2241 SoCs. Currently i.MX31/35/51 are supported.
2243 CONFIG_SYS_SPI_MXC_WAIT
2244 Timeout for waiting until spi transfer completed.
2245 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2247 - FPGA Support: CONFIG_FPGA
2249 Enables FPGA subsystem.
2251 CONFIG_FPGA_<vendor>
2253 Enables support for specific chip vendors.
2256 CONFIG_FPGA_<family>
2258 Enables support for FPGA family.
2259 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2263 Specify the number of FPGA devices to support.
2265 CONFIG_SYS_FPGA_PROG_FEEDBACK
2267 Enable printing of hash marks during FPGA configuration.
2269 CONFIG_SYS_FPGA_CHECK_BUSY
2271 Enable checks on FPGA configuration interface busy
2272 status by the configuration function. This option
2273 will require a board or device specific function to
2278 If defined, a function that provides delays in the FPGA
2279 configuration driver.
2281 CONFIG_SYS_FPGA_CHECK_CTRLC
2282 Allow Control-C to interrupt FPGA configuration
2284 CONFIG_SYS_FPGA_CHECK_ERROR
2286 Check for configuration errors during FPGA bitfile
2287 loading. For example, abort during Virtex II
2288 configuration if the INIT_B line goes low (which
2289 indicated a CRC error).
2291 CONFIG_SYS_FPGA_WAIT_INIT
2293 Maximum time to wait for the INIT_B line to de-assert
2294 after PROB_B has been de-asserted during a Virtex II
2295 FPGA configuration sequence. The default time is 500
2298 CONFIG_SYS_FPGA_WAIT_BUSY
2300 Maximum time to wait for BUSY to de-assert during
2301 Virtex II FPGA configuration. The default is 5 ms.
2303 CONFIG_SYS_FPGA_WAIT_CONFIG
2305 Time to wait after FPGA configuration. The default is
2308 - Configuration Management:
2311 Some SoCs need special image types (e.g. U-Boot binary
2312 with a special header) as build targets. By defining
2313 CONFIG_BUILD_TARGET in the SoC / board header, this
2314 special image will be automatically built upon calling
2319 If defined, this string will be added to the U-Boot
2320 version information (U_BOOT_VERSION)
2322 - Vendor Parameter Protection:
2324 U-Boot considers the values of the environment
2325 variables "serial#" (Board Serial Number) and
2326 "ethaddr" (Ethernet Address) to be parameters that
2327 are set once by the board vendor / manufacturer, and
2328 protects these variables from casual modification by
2329 the user. Once set, these variables are read-only,
2330 and write or delete attempts are rejected. You can
2331 change this behaviour:
2333 If CONFIG_ENV_OVERWRITE is #defined in your config
2334 file, the write protection for vendor parameters is
2335 completely disabled. Anybody can change or delete
2338 Alternatively, if you define _both_ an ethaddr in the
2339 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2340 Ethernet address is installed in the environment,
2341 which can be changed exactly ONCE by the user. [The
2342 serial# is unaffected by this, i. e. it remains
2345 The same can be accomplished in a more flexible way
2346 for any variable by configuring the type of access
2347 to allow for those variables in the ".flags" variable
2348 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2353 Define this variable to enable the reservation of
2354 "protected RAM", i. e. RAM which is not overwritten
2355 by U-Boot. Define CONFIG_PRAM to hold the number of
2356 kB you want to reserve for pRAM. You can overwrite
2357 this default value by defining an environment
2358 variable "pram" to the number of kB you want to
2359 reserve. Note that the board info structure will
2360 still show the full amount of RAM. If pRAM is
2361 reserved, a new environment variable "mem" will
2362 automatically be defined to hold the amount of
2363 remaining RAM in a form that can be passed as boot
2364 argument to Linux, for instance like that:
2366 setenv bootargs ... mem=\${mem}
2369 This way you can tell Linux not to use this memory,
2370 either, which results in a memory region that will
2371 not be affected by reboots.
2373 *WARNING* If your board configuration uses automatic
2374 detection of the RAM size, you must make sure that
2375 this memory test is non-destructive. So far, the
2376 following board configurations are known to be
2379 IVMS8, IVML24, SPD8xx,
2380 HERMES, IP860, RPXlite, LWMON,
2383 - Access to physical memory region (> 4GB)
2384 Some basic support is provided for operations on memory not
2385 normally accessible to U-Boot - e.g. some architectures
2386 support access to more than 4GB of memory on 32-bit
2387 machines using physical address extension or similar.
2388 Define CONFIG_PHYSMEM to access this basic support, which
2389 currently only supports clearing the memory.
2394 Define this variable to stop the system in case of a
2395 fatal error, so that you have to reset it manually.
2396 This is probably NOT a good idea for an embedded
2397 system where you want the system to reboot
2398 automatically as fast as possible, but it may be
2399 useful during development since you can try to debug
2400 the conditions that lead to the situation.
2402 CONFIG_NET_RETRY_COUNT
2404 This variable defines the number of retries for
2405 network operations like ARP, RARP, TFTP, or BOOTP
2406 before giving up the operation. If not defined, a
2407 default value of 5 is used.
2411 Timeout waiting for an ARP reply in milliseconds.
2415 Timeout in milliseconds used in NFS protocol.
2416 If you encounter "ERROR: Cannot umount" in nfs command,
2417 try longer timeout such as
2418 #define CONFIG_NFS_TIMEOUT 10000UL
2420 - Command Interpreter:
2421 CONFIG_AUTO_COMPLETE
2423 Enable auto completion of commands using TAB.
2425 CONFIG_SYS_PROMPT_HUSH_PS2
2427 This defines the secondary prompt string, which is
2428 printed when the command interpreter needs more input
2429 to complete a command. Usually "> ".
2433 In the current implementation, the local variables
2434 space and global environment variables space are
2435 separated. Local variables are those you define by
2436 simply typing `name=value'. To access a local
2437 variable later on, you have write `$name' or
2438 `${name}'; to execute the contents of a variable
2439 directly type `$name' at the command prompt.
2441 Global environment variables are those you use
2442 setenv/printenv to work with. To run a command stored
2443 in such a variable, you need to use the run command,
2444 and you must not use the '$' sign to access them.
2446 To store commands and special characters in a
2447 variable, please use double quotation marks
2448 surrounding the whole text of the variable, instead
2449 of the backslashes before semicolons and special
2452 - Command Line Editing and History:
2453 CONFIG_CMDLINE_EDITING
2455 Enable editing and History functions for interactive
2456 command line input operations
2458 - Command Line PS1/PS2 support:
2459 CONFIG_CMDLINE_PS_SUPPORT
2461 Enable support for changing the command prompt string
2462 at run-time. Only static string is supported so far.
2463 The string is obtained from environment variables PS1
2466 - Default Environment:
2467 CONFIG_EXTRA_ENV_SETTINGS
2469 Define this to contain any number of null terminated
2470 strings (variable = value pairs) that will be part of
2471 the default environment compiled into the boot image.
2473 For example, place something like this in your
2474 board's config file:
2476 #define CONFIG_EXTRA_ENV_SETTINGS \
2480 Warning: This method is based on knowledge about the
2481 internal format how the environment is stored by the
2482 U-Boot code. This is NOT an official, exported
2483 interface! Although it is unlikely that this format
2484 will change soon, there is no guarantee either.
2485 You better know what you are doing here.
2487 Note: overly (ab)use of the default environment is
2488 discouraged. Make sure to check other ways to preset
2489 the environment like the "source" command or the
2492 CONFIG_ENV_VARS_UBOOT_CONFIG
2494 Define this in order to add variables describing the
2495 U-Boot build configuration to the default environment.
2496 These will be named arch, cpu, board, vendor, and soc.
2498 Enabling this option will cause the following to be defined:
2506 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2508 Define this in order to add variables describing certain
2509 run-time determined information about the hardware to the
2510 environment. These will be named board_name, board_rev.
2512 CONFIG_DELAY_ENVIRONMENT
2514 Normally the environment is loaded when the board is
2515 initialised so that it is available to U-Boot. This inhibits
2516 that so that the environment is not available until
2517 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2518 this is instead controlled by the value of
2519 /config/load-environment.
2521 - DataFlash Support:
2522 CONFIG_HAS_DATAFLASH
2524 Defining this option enables DataFlash features and
2525 allows to read/write in Dataflash via the standard
2528 - Serial Flash support
2531 Defining this option enables SPI flash commands
2532 'sf probe/read/write/erase/update'.
2534 Usage requires an initial 'probe' to define the serial
2535 flash parameters, followed by read/write/erase/update
2538 The following defaults may be provided by the platform
2539 to handle the common case when only a single serial
2540 flash is present on the system.
2542 CONFIG_SF_DEFAULT_BUS Bus identifier
2543 CONFIG_SF_DEFAULT_CS Chip-select
2544 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2545 CONFIG_SF_DEFAULT_SPEED in Hz
2549 Define this option to include a destructive SPI flash
2552 - SystemACE Support:
2555 Adding this option adds support for Xilinx SystemACE
2556 chips attached via some sort of local bus. The address
2557 of the chip must also be defined in the
2558 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2560 #define CONFIG_SYSTEMACE
2561 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2563 When SystemACE support is added, the "ace" device type
2564 becomes available to the fat commands, i.e. fatls.
2566 - TFTP Fixed UDP Port:
2569 If this is defined, the environment variable tftpsrcp
2570 is used to supply the TFTP UDP source port value.
2571 If tftpsrcp isn't defined, the normal pseudo-random port
2572 number generator is used.
2574 Also, the environment variable tftpdstp is used to supply
2575 the TFTP UDP destination port value. If tftpdstp isn't
2576 defined, the normal port 69 is used.
2578 The purpose for tftpsrcp is to allow a TFTP server to
2579 blindly start the TFTP transfer using the pre-configured
2580 target IP address and UDP port. This has the effect of
2581 "punching through" the (Windows XP) firewall, allowing
2582 the remainder of the TFTP transfer to proceed normally.
2583 A better solution is to properly configure the firewall,
2584 but sometimes that is not allowed.
2586 - bootcount support:
2587 CONFIG_BOOTCOUNT_LIMIT
2589 This enables the bootcounter support, see:
2590 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2593 enable special bootcounter support on at91sam9xe based boards.
2595 enable special bootcounter support on da850 based boards.
2596 CONFIG_BOOTCOUNT_RAM
2597 enable support for the bootcounter in RAM
2598 CONFIG_BOOTCOUNT_I2C
2599 enable support for the bootcounter on an i2c (like RTC) device.
2600 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2601 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2603 CONFIG_BOOTCOUNT_ALEN = address len
2605 - Show boot progress:
2606 CONFIG_SHOW_BOOT_PROGRESS
2608 Defining this option allows to add some board-
2609 specific code (calling a user-provided function
2610 "show_boot_progress(int)") that enables you to show
2611 the system's boot progress on some display (for
2612 example, some LED's) on your board. At the moment,
2613 the following checkpoints are implemented:
2616 Legacy uImage format:
2619 1 common/cmd_bootm.c before attempting to boot an image
2620 -1 common/cmd_bootm.c Image header has bad magic number
2621 2 common/cmd_bootm.c Image header has correct magic number
2622 -2 common/cmd_bootm.c Image header has bad checksum
2623 3 common/cmd_bootm.c Image header has correct checksum
2624 -3 common/cmd_bootm.c Image data has bad checksum
2625 4 common/cmd_bootm.c Image data has correct checksum
2626 -4 common/cmd_bootm.c Image is for unsupported architecture
2627 5 common/cmd_bootm.c Architecture check OK
2628 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2629 6 common/cmd_bootm.c Image Type check OK
2630 -6 common/cmd_bootm.c gunzip uncompression error
2631 -7 common/cmd_bootm.c Unimplemented compression type
2632 7 common/cmd_bootm.c Uncompression OK
2633 8 common/cmd_bootm.c No uncompress/copy overwrite error
2634 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2636 9 common/image.c Start initial ramdisk verification
2637 -10 common/image.c Ramdisk header has bad magic number
2638 -11 common/image.c Ramdisk header has bad checksum
2639 10 common/image.c Ramdisk header is OK
2640 -12 common/image.c Ramdisk data has bad checksum
2641 11 common/image.c Ramdisk data has correct checksum
2642 12 common/image.c Ramdisk verification complete, start loading
2643 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2644 13 common/image.c Start multifile image verification
2645 14 common/image.c No initial ramdisk, no multifile, continue.
2647 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2649 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2650 -31 post/post.c POST test failed, detected by post_output_backlog()
2651 -32 post/post.c POST test failed, detected by post_run_single()
2653 34 common/cmd_doc.c before loading a Image from a DOC device
2654 -35 common/cmd_doc.c Bad usage of "doc" command
2655 35 common/cmd_doc.c correct usage of "doc" command
2656 -36 common/cmd_doc.c No boot device
2657 36 common/cmd_doc.c correct boot device
2658 -37 common/cmd_doc.c Unknown Chip ID on boot device
2659 37 common/cmd_doc.c correct chip ID found, device available
2660 -38 common/cmd_doc.c Read Error on boot device
2661 38 common/cmd_doc.c reading Image header from DOC device OK
2662 -39 common/cmd_doc.c Image header has bad magic number
2663 39 common/cmd_doc.c Image header has correct magic number
2664 -40 common/cmd_doc.c Error reading Image from DOC device
2665 40 common/cmd_doc.c Image header has correct magic number
2666 41 common/cmd_ide.c before loading a Image from a IDE device
2667 -42 common/cmd_ide.c Bad usage of "ide" command
2668 42 common/cmd_ide.c correct usage of "ide" command
2669 -43 common/cmd_ide.c No boot device
2670 43 common/cmd_ide.c boot device found
2671 -44 common/cmd_ide.c Device not available
2672 44 common/cmd_ide.c Device available
2673 -45 common/cmd_ide.c wrong partition selected
2674 45 common/cmd_ide.c partition selected
2675 -46 common/cmd_ide.c Unknown partition table
2676 46 common/cmd_ide.c valid partition table found
2677 -47 common/cmd_ide.c Invalid partition type
2678 47 common/cmd_ide.c correct partition type
2679 -48 common/cmd_ide.c Error reading Image Header on boot device
2680 48 common/cmd_ide.c reading Image Header from IDE device OK
2681 -49 common/cmd_ide.c Image header has bad magic number
2682 49 common/cmd_ide.c Image header has correct magic number
2683 -50 common/cmd_ide.c Image header has bad checksum
2684 50 common/cmd_ide.c Image header has correct checksum
2685 -51 common/cmd_ide.c Error reading Image from IDE device
2686 51 common/cmd_ide.c reading Image from IDE device OK
2687 52 common/cmd_nand.c before loading a Image from a NAND device
2688 -53 common/cmd_nand.c Bad usage of "nand" command
2689 53 common/cmd_nand.c correct usage of "nand" command
2690 -54 common/cmd_nand.c No boot device
2691 54 common/cmd_nand.c boot device found
2692 -55 common/cmd_nand.c Unknown Chip ID on boot device
2693 55 common/cmd_nand.c correct chip ID found, device available
2694 -56 common/cmd_nand.c Error reading Image Header on boot device
2695 56 common/cmd_nand.c reading Image Header from NAND device OK
2696 -57 common/cmd_nand.c Image header has bad magic number
2697 57 common/cmd_nand.c Image header has correct magic number
2698 -58 common/cmd_nand.c Error reading Image from NAND device
2699 58 common/cmd_nand.c reading Image from NAND device OK
2701 -60 common/env_common.c Environment has a bad CRC, using default
2703 64 net/eth.c starting with Ethernet configuration.
2704 -64 net/eth.c no Ethernet found.
2705 65 net/eth.c Ethernet found.
2707 -80 common/cmd_net.c usage wrong
2708 80 common/cmd_net.c before calling net_loop()
2709 -81 common/cmd_net.c some error in net_loop() occurred
2710 81 common/cmd_net.c net_loop() back without error
2711 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2712 82 common/cmd_net.c trying automatic boot
2713 83 common/cmd_net.c running "source" command
2714 -83 common/cmd_net.c some error in automatic boot or "source" command
2715 84 common/cmd_net.c end without errors
2720 100 common/cmd_bootm.c Kernel FIT Image has correct format
2721 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2722 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2723 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2724 102 common/cmd_bootm.c Kernel unit name specified
2725 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2726 103 common/cmd_bootm.c Found configuration node
2727 104 common/cmd_bootm.c Got kernel subimage node offset
2728 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2729 105 common/cmd_bootm.c Kernel subimage hash verification OK
2730 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2731 106 common/cmd_bootm.c Architecture check OK
2732 -106 common/cmd_bootm.c Kernel subimage has wrong type
2733 107 common/cmd_bootm.c Kernel subimage type OK
2734 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2735 108 common/cmd_bootm.c Got kernel subimage data/size
2736 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2737 -109 common/cmd_bootm.c Can't get kernel subimage type
2738 -110 common/cmd_bootm.c Can't get kernel subimage comp
2739 -111 common/cmd_bootm.c Can't get kernel subimage os
2740 -112 common/cmd_bootm.c Can't get kernel subimage load address
2741 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2743 120 common/image.c Start initial ramdisk verification
2744 -120 common/image.c Ramdisk FIT image has incorrect format
2745 121 common/image.c Ramdisk FIT image has correct format
2746 122 common/image.c No ramdisk subimage unit name, using configuration
2747 -122 common/image.c Can't get configuration for ramdisk subimage
2748 123 common/image.c Ramdisk unit name specified
2749 -124 common/image.c Can't get ramdisk subimage node offset
2750 125 common/image.c Got ramdisk subimage node offset
2751 -125 common/image.c Ramdisk subimage hash verification failed
2752 126 common/image.c Ramdisk subimage hash verification OK
2753 -126 common/image.c Ramdisk subimage for unsupported architecture
2754 127 common/image.c Architecture check OK
2755 -127 common/image.c Can't get ramdisk subimage data/size
2756 128 common/image.c Got ramdisk subimage data/size
2757 129 common/image.c Can't get ramdisk load address
2758 -129 common/image.c Got ramdisk load address
2760 -130 common/cmd_doc.c Incorrect FIT image format
2761 131 common/cmd_doc.c FIT image format OK
2763 -140 common/cmd_ide.c Incorrect FIT image format
2764 141 common/cmd_ide.c FIT image format OK
2766 -150 common/cmd_nand.c Incorrect FIT image format
2767 151 common/cmd_nand.c FIT image format OK
2769 - legacy image format:
2770 CONFIG_IMAGE_FORMAT_LEGACY
2771 enables the legacy image format support in U-Boot.
2774 enabled if CONFIG_FIT_SIGNATURE is not defined.
2776 CONFIG_DISABLE_IMAGE_LEGACY
2777 disable the legacy image format
2779 This define is introduced, as the legacy image format is
2780 enabled per default for backward compatibility.
2782 - Standalone program support:
2783 CONFIG_STANDALONE_LOAD_ADDR
2785 This option defines a board specific value for the
2786 address where standalone program gets loaded, thus
2787 overwriting the architecture dependent default
2790 - Frame Buffer Address:
2793 Define CONFIG_FB_ADDR if you want to use specific
2794 address for frame buffer. This is typically the case
2795 when using a graphics controller has separate video
2796 memory. U-Boot will then place the frame buffer at
2797 the given address instead of dynamically reserving it
2798 in system RAM by calling lcd_setmem(), which grabs
2799 the memory for the frame buffer depending on the
2800 configured panel size.
2802 Please see board_init_f function.
2804 - Automatic software updates via TFTP server
2806 CONFIG_UPDATE_TFTP_CNT_MAX
2807 CONFIG_UPDATE_TFTP_MSEC_MAX
2809 These options enable and control the auto-update feature;
2810 for a more detailed description refer to doc/README.update.
2812 - MTD Support (mtdparts command, UBI support)
2815 Adds the MTD device infrastructure from the Linux kernel.
2816 Needed for mtdparts command support.
2818 CONFIG_MTD_PARTITIONS
2820 Adds the MTD partitioning infrastructure from the Linux
2821 kernel. Needed for UBI support.
2826 Adds commands for interacting with MTD partitions formatted
2827 with the UBI flash translation layer
2829 Requires also defining CONFIG_RBTREE
2831 CONFIG_UBI_SILENCE_MSG
2833 Make the verbose messages from UBI stop printing. This leaves
2834 warnings and errors enabled.
2837 CONFIG_MTD_UBI_WL_THRESHOLD
2838 This parameter defines the maximum difference between the highest
2839 erase counter value and the lowest erase counter value of eraseblocks
2840 of UBI devices. When this threshold is exceeded, UBI starts performing
2841 wear leveling by means of moving data from eraseblock with low erase
2842 counter to eraseblocks with high erase counter.
2844 The default value should be OK for SLC NAND flashes, NOR flashes and
2845 other flashes which have eraseblock life-cycle 100000 or more.
2846 However, in case of MLC NAND flashes which typically have eraseblock
2847 life-cycle less than 10000, the threshold should be lessened (e.g.,
2848 to 128 or 256, although it does not have to be power of 2).
2852 CONFIG_MTD_UBI_BEB_LIMIT
2853 This option specifies the maximum bad physical eraseblocks UBI
2854 expects on the MTD device (per 1024 eraseblocks). If the
2855 underlying flash does not admit of bad eraseblocks (e.g. NOR
2856 flash), this value is ignored.
2858 NAND datasheets often specify the minimum and maximum NVM
2859 (Number of Valid Blocks) for the flashes' endurance lifetime.
2860 The maximum expected bad eraseblocks per 1024 eraseblocks
2861 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2862 which gives 20 for most NANDs (MaxNVB is basically the total
2863 count of eraseblocks on the chip).
2865 To put it differently, if this value is 20, UBI will try to
2866 reserve about 1.9% of physical eraseblocks for bad blocks
2867 handling. And that will be 1.9% of eraseblocks on the entire
2868 NAND chip, not just the MTD partition UBI attaches. This means
2869 that if you have, say, a NAND flash chip admits maximum 40 bad
2870 eraseblocks, and it is split on two MTD partitions of the same
2871 size, UBI will reserve 40 eraseblocks when attaching a
2876 CONFIG_MTD_UBI_FASTMAP
2877 Fastmap is a mechanism which allows attaching an UBI device
2878 in nearly constant time. Instead of scanning the whole MTD device it
2879 only has to locate a checkpoint (called fastmap) on the device.
2880 The on-flash fastmap contains all information needed to attach
2881 the device. Using fastmap makes only sense on large devices where
2882 attaching by scanning takes long. UBI will not automatically install
2883 a fastmap on old images, but you can set the UBI parameter
2884 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2885 that fastmap-enabled images are still usable with UBI implementations
2886 without fastmap support. On typical flash devices the whole fastmap
2887 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2889 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2890 Set this parameter to enable fastmap automatically on images
2894 CONFIG_MTD_UBI_FM_DEBUG
2895 Enable UBI fastmap debug
2901 Adds commands for interacting with UBI volumes formatted as
2902 UBIFS. UBIFS is read-only in u-boot.
2904 Requires UBI support as well as CONFIG_LZO
2906 CONFIG_UBIFS_SILENCE_MSG
2908 Make the verbose messages from UBIFS stop printing. This leaves
2909 warnings and errors enabled.
2913 Enable building of SPL globally.
2916 LDSCRIPT for linking the SPL binary.
2918 CONFIG_SPL_MAX_FOOTPRINT
2919 Maximum size in memory allocated to the SPL, BSS included.
2920 When defined, the linker checks that the actual memory
2921 used by SPL from _start to __bss_end does not exceed it.
2922 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2923 must not be both defined at the same time.
2926 Maximum size of the SPL image (text, data, rodata, and
2927 linker lists sections), BSS excluded.
2928 When defined, the linker checks that the actual size does
2931 CONFIG_SPL_TEXT_BASE
2932 TEXT_BASE for linking the SPL binary.
2934 CONFIG_SPL_RELOC_TEXT_BASE
2935 Address to relocate to. If unspecified, this is equal to
2936 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2938 CONFIG_SPL_BSS_START_ADDR
2939 Link address for the BSS within the SPL binary.
2941 CONFIG_SPL_BSS_MAX_SIZE
2942 Maximum size in memory allocated to the SPL BSS.
2943 When defined, the linker checks that the actual memory used
2944 by SPL from __bss_start to __bss_end does not exceed it.
2945 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2946 must not be both defined at the same time.
2949 Adress of the start of the stack SPL will use
2951 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2952 When defined, SPL will panic() if the image it has
2953 loaded does not have a signature.
2954 Defining this is useful when code which loads images
2955 in SPL cannot guarantee that absolutely all read errors
2957 An example is the LPC32XX MLC NAND driver, which will
2958 consider that a completely unreadable NAND block is bad,
2959 and thus should be skipped silently.
2961 CONFIG_SPL_RELOC_STACK
2962 Adress of the start of the stack SPL will use after
2963 relocation. If unspecified, this is equal to
2966 CONFIG_SYS_SPL_MALLOC_START
2967 Starting address of the malloc pool used in SPL.
2968 When this option is set the full malloc is used in SPL and
2969 it is set up by spl_init() and before that, the simple malloc()
2970 can be used if CONFIG_SYS_MALLOC_F is defined.
2972 CONFIG_SYS_SPL_MALLOC_SIZE
2973 The size of the malloc pool used in SPL.
2975 CONFIG_SPL_FRAMEWORK
2976 Enable the SPL framework under common/. This framework
2977 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2978 NAND loading of the Linux Kernel.
2981 Enable booting directly to an OS from SPL.
2982 See also: doc/README.falcon
2984 CONFIG_SPL_DISPLAY_PRINT
2985 For ARM, enable an optional function to print more information
2986 about the running system.
2988 CONFIG_SPL_INIT_MINIMAL
2989 Arch init code should be built for a very small image
2991 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2992 Partition on the MMC to load U-Boot from when the MMC is being
2995 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2996 Sector to load kernel uImage from when MMC is being
2997 used in raw mode (for Falcon mode)
2999 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3000 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3001 Sector and number of sectors to load kernel argument
3002 parameters from when MMC is being used in raw mode
3005 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3006 Partition on the MMC to load U-Boot from when the MMC is being
3009 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3010 Filename to read to load U-Boot when reading from filesystem
3012 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3013 Filename to read to load kernel uImage when reading
3014 from filesystem (for Falcon mode)
3016 CONFIG_SPL_FS_LOAD_ARGS_NAME
3017 Filename to read to load kernel argument parameters
3018 when reading from filesystem (for Falcon mode)
3020 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3021 Set this for NAND SPL on PPC mpc83xx targets, so that
3022 start.S waits for the rest of the SPL to load before
3023 continuing (the hardware starts execution after just
3024 loading the first page rather than the full 4K).
3026 CONFIG_SPL_SKIP_RELOCATE
3027 Avoid SPL relocation
3029 CONFIG_SPL_NAND_BASE
3030 Include nand_base.c in the SPL. Requires
3031 CONFIG_SPL_NAND_DRIVERS.
3033 CONFIG_SPL_NAND_DRIVERS
3034 SPL uses normal NAND drivers, not minimal drivers.
3037 Include standard software ECC in the SPL
3039 CONFIG_SPL_NAND_SIMPLE
3040 Support for NAND boot using simple NAND drivers that
3041 expose the cmd_ctrl() interface.
3044 Support for a lightweight UBI (fastmap) scanner and
3047 CONFIG_SPL_NAND_RAW_ONLY
3048 Support to boot only raw u-boot.bin images. Use this only
3049 if you need to save space.
3051 CONFIG_SPL_COMMON_INIT_DDR
3052 Set for common ddr init with serial presence detect in
3055 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3056 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3057 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3058 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3059 CONFIG_SYS_NAND_ECCBYTES
3060 Defines the size and behavior of the NAND that SPL uses
3063 CONFIG_SPL_NAND_BOOT
3064 Add support NAND boot
3066 CONFIG_SYS_NAND_U_BOOT_OFFS
3067 Location in NAND to read U-Boot from
3069 CONFIG_SYS_NAND_U_BOOT_DST
3070 Location in memory to load U-Boot to
3072 CONFIG_SYS_NAND_U_BOOT_SIZE
3073 Size of image to load
3075 CONFIG_SYS_NAND_U_BOOT_START
3076 Entry point in loaded image to jump to
3078 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3079 Define this if you need to first read the OOB and then the
3080 data. This is used, for example, on davinci platforms.
3082 CONFIG_SPL_OMAP3_ID_NAND
3083 Support for an OMAP3-specific set of functions to return the
3084 ID and MFR of the first attached NAND chip, if present.
3086 CONFIG_SPL_RAM_DEVICE
3087 Support for running image already present in ram, in SPL binary
3090 Image offset to which the SPL should be padded before appending
3091 the SPL payload. By default, this is defined as
3092 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3093 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3094 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3097 Final target image containing SPL and payload. Some SPLs
3098 use an arch-specific makefile fragment instead, for
3099 example if more than one image needs to be produced.
3101 CONFIG_FIT_SPL_PRINT
3102 Printing information about a FIT image adds quite a bit of
3103 code to SPL. So this is normally disabled in SPL. Use this
3104 option to re-enable it. This will affect the output of the
3105 bootm command when booting a FIT image.
3109 Enable building of TPL globally.
3112 Image offset to which the TPL should be padded before appending
3113 the TPL payload. By default, this is defined as
3114 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3115 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3116 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3118 - Interrupt support (PPC):
3120 There are common interrupt_init() and timer_interrupt()
3121 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3122 for CPU specific initialization. interrupt_init_cpu()
3123 should set decrementer_count to appropriate value. If
3124 CPU resets decrementer automatically after interrupt
3125 (ppc4xx) it should set decrementer_count to zero.
3126 timer_interrupt() calls timer_interrupt_cpu() for CPU
3127 specific handling. If board has watchdog / status_led
3128 / other_activity_monitor it works automatically from
3129 general timer_interrupt().
3132 Board initialization settings:
3133 ------------------------------
3135 During Initialization u-boot calls a number of board specific functions
3136 to allow the preparation of board specific prerequisites, e.g. pin setup
3137 before drivers are initialized. To enable these callbacks the
3138 following configuration macros have to be defined. Currently this is
3139 architecture specific, so please check arch/your_architecture/lib/board.c
3140 typically in board_init_f() and board_init_r().
3142 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3143 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3144 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3145 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3147 Configuration Settings:
3148 -----------------------
3150 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3151 Optionally it can be defined to support 64-bit memory commands.
3153 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3154 undefine this when you're short of memory.
3156 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3157 width of the commands listed in the 'help' command output.
3159 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3160 prompt for user input.
3162 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3164 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3166 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3168 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3169 the application (usually a Linux kernel) when it is
3172 - CONFIG_SYS_BAUDRATE_TABLE:
3173 List of legal baudrate settings for this board.
3175 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3176 Begin and End addresses of the area used by the
3179 - CONFIG_SYS_ALT_MEMTEST:
3180 Enable an alternate, more extensive memory test.
3182 - CONFIG_SYS_MEMTEST_SCRATCH:
3183 Scratch address used by the alternate memory test
3184 You only need to set this if address zero isn't writeable
3186 - CONFIG_SYS_MEM_RESERVE_SECURE
3187 Only implemented for ARMv8 for now.
3188 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3189 is substracted from total RAM and won't be reported to OS.
3190 This memory can be used as secure memory. A variable
3191 gd->arch.secure_ram is used to track the location. In systems
3192 the RAM base is not zero, or RAM is divided into banks,
3193 this variable needs to be recalcuated to get the address.
3195 - CONFIG_SYS_MEM_TOP_HIDE:
3196 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3197 this specified memory area will get subtracted from the top
3198 (end) of RAM and won't get "touched" at all by U-Boot. By
3199 fixing up gd->ram_size the Linux kernel should gets passed
3200 the now "corrected" memory size and won't touch it either.
3201 This should work for arch/ppc and arch/powerpc. Only Linux
3202 board ports in arch/powerpc with bootwrapper support that
3203 recalculate the memory size from the SDRAM controller setup
3204 will have to get fixed in Linux additionally.
3206 This option can be used as a workaround for the 440EPx/GRx
3207 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3210 WARNING: Please make sure that this value is a multiple of
3211 the Linux page size (normally 4k). If this is not the case,
3212 then the end address of the Linux memory will be located at a
3213 non page size aligned address and this could cause major
3216 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3217 Enable temporary baudrate change while serial download
3219 - CONFIG_SYS_SDRAM_BASE:
3220 Physical start address of SDRAM. _Must_ be 0 here.
3222 - CONFIG_SYS_FLASH_BASE:
3223 Physical start address of Flash memory.
3225 - CONFIG_SYS_MONITOR_BASE:
3226 Physical start address of boot monitor code (set by
3227 make config files to be same as the text base address
3228 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3229 CONFIG_SYS_FLASH_BASE when booting from flash.
3231 - CONFIG_SYS_MONITOR_LEN:
3232 Size of memory reserved for monitor code, used to
3233 determine _at_compile_time_ (!) if the environment is
3234 embedded within the U-Boot image, or in a separate
3237 - CONFIG_SYS_MALLOC_LEN:
3238 Size of DRAM reserved for malloc() use.
3240 - CONFIG_SYS_MALLOC_F_LEN
3241 Size of the malloc() pool for use before relocation. If
3242 this is defined, then a very simple malloc() implementation
3243 will become available before relocation. The address is just
3244 below the global data, and the stack is moved down to make
3247 This feature allocates regions with increasing addresses
3248 within the region. calloc() is supported, but realloc()
3249 is not available. free() is supported but does nothing.
3250 The memory will be freed (or in fact just forgotten) when
3251 U-Boot relocates itself.
3253 - CONFIG_SYS_MALLOC_SIMPLE
3254 Provides a simple and small malloc() and calloc() for those
3255 boards which do not use the full malloc in SPL (which is
3256 enabled with CONFIG_SYS_SPL_MALLOC_START).
3258 - CONFIG_SYS_NONCACHED_MEMORY:
3259 Size of non-cached memory area. This area of memory will be
3260 typically located right below the malloc() area and mapped
3261 uncached in the MMU. This is useful for drivers that would
3262 otherwise require a lot of explicit cache maintenance. For
3263 some drivers it's also impossible to properly maintain the
3264 cache. For example if the regions that need to be flushed
3265 are not a multiple of the cache-line size, *and* padding
3266 cannot be allocated between the regions to align them (i.e.
3267 if the HW requires a contiguous array of regions, and the
3268 size of each region is not cache-aligned), then a flush of
3269 one region may result in overwriting data that hardware has
3270 written to another region in the same cache-line. This can
3271 happen for example in network drivers where descriptors for
3272 buffers are typically smaller than the CPU cache-line (e.g.
3273 16 bytes vs. 32 or 64 bytes).
3275 Non-cached memory is only supported on 32-bit ARM at present.
3277 - CONFIG_SYS_BOOTM_LEN:
3278 Normally compressed uImages are limited to an
3279 uncompressed size of 8 MBytes. If this is not enough,
3280 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3281 to adjust this setting to your needs.
3283 - CONFIG_SYS_BOOTMAPSZ:
3284 Maximum size of memory mapped by the startup code of
3285 the Linux kernel; all data that must be processed by
3286 the Linux kernel (bd_info, boot arguments, FDT blob if
3287 used) must be put below this limit, unless "bootm_low"
3288 environment variable is defined and non-zero. In such case
3289 all data for the Linux kernel must be between "bootm_low"
3290 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3291 variable "bootm_mapsize" will override the value of
3292 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3293 then the value in "bootm_size" will be used instead.
3295 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3296 Enable initrd_high functionality. If defined then the
3297 initrd_high feature is enabled and the bootm ramdisk subcommand
3300 - CONFIG_SYS_BOOT_GET_CMDLINE:
3301 Enables allocating and saving kernel cmdline in space between
3302 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3304 - CONFIG_SYS_BOOT_GET_KBD:
3305 Enables allocating and saving a kernel copy of the bd_info in
3306 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3308 - CONFIG_SYS_MAX_FLASH_BANKS:
3309 Max number of Flash memory banks
3311 - CONFIG_SYS_MAX_FLASH_SECT:
3312 Max number of sectors on a Flash chip
3314 - CONFIG_SYS_FLASH_ERASE_TOUT:
3315 Timeout for Flash erase operations (in ms)
3317 - CONFIG_SYS_FLASH_WRITE_TOUT:
3318 Timeout for Flash write operations (in ms)
3320 - CONFIG_SYS_FLASH_LOCK_TOUT
3321 Timeout for Flash set sector lock bit operation (in ms)
3323 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3324 Timeout for Flash clear lock bits operation (in ms)
3326 - CONFIG_SYS_FLASH_PROTECTION
3327 If defined, hardware flash sectors protection is used
3328 instead of U-Boot software protection.
3330 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3332 Enable TFTP transfers directly to flash memory;
3333 without this option such a download has to be
3334 performed in two steps: (1) download to RAM, and (2)
3335 copy from RAM to flash.
3337 The two-step approach is usually more reliable, since
3338 you can check if the download worked before you erase
3339 the flash, but in some situations (when system RAM is
3340 too limited to allow for a temporary copy of the
3341 downloaded image) this option may be very useful.
3343 - CONFIG_SYS_FLASH_CFI:
3344 Define if the flash driver uses extra elements in the
3345 common flash structure for storing flash geometry.
3347 - CONFIG_FLASH_CFI_DRIVER
3348 This option also enables the building of the cfi_flash driver
3349 in the drivers directory
3351 - CONFIG_FLASH_CFI_MTD
3352 This option enables the building of the cfi_mtd driver
3353 in the drivers directory. The driver exports CFI flash
3356 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3357 Use buffered writes to flash.
3359 - CONFIG_FLASH_SPANSION_S29WS_N
3360 s29ws-n MirrorBit flash has non-standard addresses for buffered
3363 - CONFIG_SYS_FLASH_QUIET_TEST
3364 If this option is defined, the common CFI flash doesn't
3365 print it's warning upon not recognized FLASH banks. This
3366 is useful, if some of the configured banks are only
3367 optionally available.
3369 - CONFIG_FLASH_SHOW_PROGRESS
3370 If defined (must be an integer), print out countdown
3371 digits and dots. Recommended value: 45 (9..1) for 80
3372 column displays, 15 (3..1) for 40 column displays.
3374 - CONFIG_FLASH_VERIFY
3375 If defined, the content of the flash (destination) is compared
3376 against the source after the write operation. An error message
3377 will be printed when the contents are not identical.
3378 Please note that this option is useless in nearly all cases,
3379 since such flash programming errors usually are detected earlier
3380 while unprotecting/erasing/programming. Please only enable
3381 this option if you really know what you are doing.
3383 - CONFIG_SYS_RX_ETH_BUFFER:
3384 Defines the number of Ethernet receive buffers. On some
3385 Ethernet controllers it is recommended to set this value
3386 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3387 buffers can be full shortly after enabling the interface
3388 on high Ethernet traffic.
3389 Defaults to 4 if not defined.
3391 - CONFIG_ENV_MAX_ENTRIES
3393 Maximum number of entries in the hash table that is used
3394 internally to store the environment settings. The default
3395 setting is supposed to be generous and should work in most
3396 cases. This setting can be used to tune behaviour; see
3397 lib/hashtable.c for details.
3399 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3400 - CONFIG_ENV_FLAGS_LIST_STATIC
3401 Enable validation of the values given to environment variables when
3402 calling env set. Variables can be restricted to only decimal,
3403 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3404 the variables can also be restricted to IP address or MAC address.
3406 The format of the list is:
3407 type_attribute = [s|d|x|b|i|m]
3408 access_attribute = [a|r|o|c]
3409 attributes = type_attribute[access_attribute]
3410 entry = variable_name[:attributes]
3413 The type attributes are:
3414 s - String (default)
3417 b - Boolean ([1yYtT|0nNfF])
3421 The access attributes are:
3427 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3428 Define this to a list (string) to define the ".flags"
3429 environment variable in the default or embedded environment.
3431 - CONFIG_ENV_FLAGS_LIST_STATIC
3432 Define this to a list (string) to define validation that
3433 should be done if an entry is not found in the ".flags"
3434 environment variable. To override a setting in the static
3435 list, simply add an entry for the same variable name to the
3438 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3439 regular expression. This allows multiple variables to define the same
3440 flags without explicitly listing them for each variable.
3442 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3443 If defined, don't allow the -f switch to env set override variable
3447 If stdint.h is available with your toolchain you can define this
3448 option to enable it. You can provide option 'USE_STDINT=1' when
3449 building U-Boot to enable this.
3451 The following definitions that deal with the placement and management
3452 of environment data (variable area); in general, we support the
3453 following configurations:
3455 - CONFIG_BUILD_ENVCRC:
3457 Builds up envcrc with the target environment so that external utils
3458 may easily extract it and embed it in final U-Boot images.
3460 - CONFIG_ENV_IS_IN_FLASH:
3462 Define this if the environment is in flash memory.
3464 a) The environment occupies one whole flash sector, which is
3465 "embedded" in the text segment with the U-Boot code. This
3466 happens usually with "bottom boot sector" or "top boot
3467 sector" type flash chips, which have several smaller
3468 sectors at the start or the end. For instance, such a
3469 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3470 such a case you would place the environment in one of the
3471 4 kB sectors - with U-Boot code before and after it. With
3472 "top boot sector" type flash chips, you would put the
3473 environment in one of the last sectors, leaving a gap
3474 between U-Boot and the environment.
3476 - CONFIG_ENV_OFFSET:
3478 Offset of environment data (variable area) to the
3479 beginning of flash memory; for instance, with bottom boot
3480 type flash chips the second sector can be used: the offset
3481 for this sector is given here.
3483 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3487 This is just another way to specify the start address of
3488 the flash sector containing the environment (instead of
3491 - CONFIG_ENV_SECT_SIZE:
3493 Size of the sector containing the environment.
3496 b) Sometimes flash chips have few, equal sized, BIG sectors.
3497 In such a case you don't want to spend a whole sector for
3502 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3503 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3504 of this flash sector for the environment. This saves
3505 memory for the RAM copy of the environment.
3507 It may also save flash memory if you decide to use this
3508 when your environment is "embedded" within U-Boot code,
3509 since then the remainder of the flash sector could be used
3510 for U-Boot code. It should be pointed out that this is
3511 STRONGLY DISCOURAGED from a robustness point of view:
3512 updating the environment in flash makes it always
3513 necessary to erase the WHOLE sector. If something goes
3514 wrong before the contents has been restored from a copy in
3515 RAM, your target system will be dead.
3517 - CONFIG_ENV_ADDR_REDUND
3518 CONFIG_ENV_SIZE_REDUND
3520 These settings describe a second storage area used to hold
3521 a redundant copy of the environment data, so that there is
3522 a valid backup copy in case there is a power failure during
3523 a "saveenv" operation.
3525 BE CAREFUL! Any changes to the flash layout, and some changes to the
3526 source code will make it necessary to adapt <board>/u-boot.lds*
3530 - CONFIG_ENV_IS_IN_NVRAM:
3532 Define this if you have some non-volatile memory device
3533 (NVRAM, battery buffered SRAM) which you want to use for the
3539 These two #defines are used to determine the memory area you
3540 want to use for environment. It is assumed that this memory
3541 can just be read and written to, without any special
3544 BE CAREFUL! The first access to the environment happens quite early
3545 in U-Boot initialization (when we try to get the setting of for the
3546 console baudrate). You *MUST* have mapped your NVRAM area then, or
3549 Please note that even with NVRAM we still use a copy of the
3550 environment in RAM: we could work on NVRAM directly, but we want to
3551 keep settings there always unmodified except somebody uses "saveenv"
3552 to save the current settings.
3555 - CONFIG_ENV_IS_IN_EEPROM:
3557 Use this if you have an EEPROM or similar serial access
3558 device and a driver for it.
3560 - CONFIG_ENV_OFFSET:
3563 These two #defines specify the offset and size of the
3564 environment area within the total memory of your EEPROM.
3566 - CONFIG_SYS_I2C_EEPROM_ADDR:
3567 If defined, specified the chip address of the EEPROM device.
3568 The default address is zero.
3570 - CONFIG_SYS_I2C_EEPROM_BUS:
3571 If defined, specified the i2c bus of the EEPROM device.
3573 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3574 If defined, the number of bits used to address bytes in a
3575 single page in the EEPROM device. A 64 byte page, for example
3576 would require six bits.
3578 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3579 If defined, the number of milliseconds to delay between
3580 page writes. The default is zero milliseconds.
3582 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3583 The length in bytes of the EEPROM memory array address. Note
3584 that this is NOT the chip address length!
3586 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3587 EEPROM chips that implement "address overflow" are ones
3588 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3589 address and the extra bits end up in the "chip address" bit
3590 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3593 Note that we consider the length of the address field to
3594 still be one byte because the extra address bits are hidden
3595 in the chip address.
3597 - CONFIG_SYS_EEPROM_SIZE:
3598 The size in bytes of the EEPROM device.
3600 - CONFIG_ENV_EEPROM_IS_ON_I2C
3601 define this, if you have I2C and SPI activated, and your
3602 EEPROM, which holds the environment, is on the I2C bus.
3604 - CONFIG_I2C_ENV_EEPROM_BUS
3605 if you have an Environment on an EEPROM reached over
3606 I2C muxes, you can define here, how to reach this
3607 EEPROM. For example:
3609 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3611 EEPROM which holds the environment, is reached over
3612 a pca9547 i2c mux with address 0x70, channel 3.
3614 - CONFIG_ENV_IS_IN_DATAFLASH:
3616 Define this if you have a DataFlash memory device which you
3617 want to use for the environment.
3619 - CONFIG_ENV_OFFSET:
3623 These three #defines specify the offset and size of the
3624 environment area within the total memory of your DataFlash placed
3625 at the specified address.
3627 - CONFIG_ENV_IS_IN_SPI_FLASH:
3629 Define this if you have a SPI Flash memory device which you
3630 want to use for the environment.
3632 - CONFIG_ENV_OFFSET:
3635 These two #defines specify the offset and size of the
3636 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3637 aligned to an erase sector boundary.
3639 - CONFIG_ENV_SECT_SIZE:
3641 Define the SPI flash's sector size.
3643 - CONFIG_ENV_OFFSET_REDUND (optional):
3645 This setting describes a second storage area of CONFIG_ENV_SIZE
3646 size used to hold a redundant copy of the environment data, so
3647 that there is a valid backup copy in case there is a power failure
3648 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3649 aligned to an erase sector boundary.
3651 - CONFIG_ENV_SPI_BUS (optional):
3652 - CONFIG_ENV_SPI_CS (optional):
3654 Define the SPI bus and chip select. If not defined they will be 0.
3656 - CONFIG_ENV_SPI_MAX_HZ (optional):
3658 Define the SPI max work clock. If not defined then use 1MHz.
3660 - CONFIG_ENV_SPI_MODE (optional):
3662 Define the SPI work mode. If not defined then use SPI_MODE_3.
3664 - CONFIG_ENV_IS_IN_REMOTE:
3666 Define this if you have a remote memory space which you
3667 want to use for the local device's environment.
3672 These two #defines specify the address and size of the
3673 environment area within the remote memory space. The
3674 local device can get the environment from remote memory
3675 space by SRIO or PCIE links.
3677 BE CAREFUL! For some special cases, the local device can not use
3678 "saveenv" command. For example, the local device will get the
3679 environment stored in a remote NOR flash by SRIO or PCIE link,
3680 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3682 - CONFIG_ENV_IS_IN_NAND:
3684 Define this if you have a NAND device which you want to use
3685 for the environment.
3687 - CONFIG_ENV_OFFSET:
3690 These two #defines specify the offset and size of the environment
3691 area within the first NAND device. CONFIG_ENV_OFFSET must be
3692 aligned to an erase block boundary.
3694 - CONFIG_ENV_OFFSET_REDUND (optional):
3696 This setting describes a second storage area of CONFIG_ENV_SIZE
3697 size used to hold a redundant copy of the environment data, so
3698 that there is a valid backup copy in case there is a power failure
3699 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3700 aligned to an erase block boundary.
3702 - CONFIG_ENV_RANGE (optional):
3704 Specifies the length of the region in which the environment
3705 can be written. This should be a multiple of the NAND device's
3706 block size. Specifying a range with more erase blocks than
3707 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3708 the range to be avoided.
3710 - CONFIG_ENV_OFFSET_OOB (optional):
3712 Enables support for dynamically retrieving the offset of the
3713 environment from block zero's out-of-band data. The
3714 "nand env.oob" command can be used to record this offset.
3715 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3716 using CONFIG_ENV_OFFSET_OOB.
3718 - CONFIG_NAND_ENV_DST
3720 Defines address in RAM to which the nand_spl code should copy the
3721 environment. If redundant environment is used, it will be copied to
3722 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3724 - CONFIG_ENV_IS_IN_UBI:
3726 Define this if you have an UBI volume that you want to use for the
3727 environment. This has the benefit of wear-leveling the environment
3728 accesses, which is important on NAND.
3730 - CONFIG_ENV_UBI_PART:
3732 Define this to a string that is the mtd partition containing the UBI.
3734 - CONFIG_ENV_UBI_VOLUME:
3736 Define this to the name of the volume that you want to store the
3739 - CONFIG_ENV_UBI_VOLUME_REDUND:
3741 Define this to the name of another volume to store a second copy of
3742 the environment in. This will enable redundant environments in UBI.
3743 It is assumed that both volumes are in the same MTD partition.
3745 - CONFIG_UBI_SILENCE_MSG
3746 - CONFIG_UBIFS_SILENCE_MSG
3748 You will probably want to define these to avoid a really noisy system
3749 when storing the env in UBI.
3751 - CONFIG_ENV_IS_IN_FAT:
3752 Define this if you want to use the FAT file system for the environment.
3754 - FAT_ENV_INTERFACE:
3756 Define this to a string that is the name of the block device.
3758 - FAT_ENV_DEVICE_AND_PART:
3760 Define this to a string to specify the partition of the device. It can
3763 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3764 - "D:P": device D partition P. Error occurs if device D has no
3767 - "D" or "D:": device D partition 1 if device D has partition
3768 table, or the whole device D if has no partition
3770 - "D:auto": first partition in device D with bootable flag set.
3771 If none, first valid partition in device D. If no
3772 partition table then means device D.
3776 It's a string of the FAT file name. This file use to store the
3780 This must be enabled. Otherwise it cannot save the environment file.
3782 - CONFIG_ENV_IS_IN_MMC:
3784 Define this if you have an MMC device which you want to use for the
3787 - CONFIG_SYS_MMC_ENV_DEV:
3789 Specifies which MMC device the environment is stored in.
3791 - CONFIG_SYS_MMC_ENV_PART (optional):
3793 Specifies which MMC partition the environment is stored in. If not
3794 set, defaults to partition 0, the user area. Common values might be
3795 1 (first MMC boot partition), 2 (second MMC boot partition).
3797 - CONFIG_ENV_OFFSET:
3800 These two #defines specify the offset and size of the environment
3801 area within the specified MMC device.
3803 If offset is positive (the usual case), it is treated as relative to
3804 the start of the MMC partition. If offset is negative, it is treated
3805 as relative to the end of the MMC partition. This can be useful if
3806 your board may be fitted with different MMC devices, which have
3807 different sizes for the MMC partitions, and you always want the
3808 environment placed at the very end of the partition, to leave the
3809 maximum possible space before it, to store other data.
3811 These two values are in units of bytes, but must be aligned to an
3812 MMC sector boundary.
3814 - CONFIG_ENV_OFFSET_REDUND (optional):
3816 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3817 hold a redundant copy of the environment data. This provides a
3818 valid backup copy in case the other copy is corrupted, e.g. due
3819 to a power failure during a "saveenv" operation.
3821 This value may also be positive or negative; this is handled in the
3822 same way as CONFIG_ENV_OFFSET.
3824 This value is also in units of bytes, but must also be aligned to
3825 an MMC sector boundary.
3827 - CONFIG_ENV_SIZE_REDUND (optional):
3829 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3830 set. If this value is set, it must be set to the same value as
3833 Please note that the environment is read-only until the monitor
3834 has been relocated to RAM and a RAM copy of the environment has been
3835 created; also, when using EEPROM you will have to use getenv_f()
3836 until then to read environment variables.
3838 The environment is protected by a CRC32 checksum. Before the monitor
3839 is relocated into RAM, as a result of a bad CRC you will be working
3840 with the compiled-in default environment - *silently*!!! [This is
3841 necessary, because the first environment variable we need is the
3842 "baudrate" setting for the console - if we have a bad CRC, we don't
3843 have any device yet where we could complain.]
3845 Note: once the monitor has been relocated, then it will complain if
3846 the default environment is used; a new CRC is computed as soon as you
3847 use the "saveenv" command to store a valid environment.
3849 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3850 Echo the inverted Ethernet link state to the fault LED.
3852 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3853 also needs to be defined.
3855 - CONFIG_SYS_FAULT_MII_ADDR:
3856 MII address of the PHY to check for the Ethernet link state.
3858 - CONFIG_NS16550_MIN_FUNCTIONS:
3859 Define this if you desire to only have use of the NS16550_init
3860 and NS16550_putc functions for the serial driver located at
3861 drivers/serial/ns16550.c. This option is useful for saving
3862 space for already greatly restricted images, including but not
3863 limited to NAND_SPL configurations.
3865 - CONFIG_DISPLAY_BOARDINFO
3866 Display information about the board that U-Boot is running on
3867 when U-Boot starts up. The board function checkboard() is called
3870 - CONFIG_DISPLAY_BOARDINFO_LATE
3871 Similar to the previous option, but display this information
3872 later, once stdio is running and output goes to the LCD, if
3875 - CONFIG_BOARD_SIZE_LIMIT:
3876 Maximum size of the U-Boot image. When defined, the
3877 build system checks that the actual size does not
3880 Low Level (hardware related) configuration options:
3881 ---------------------------------------------------
3883 - CONFIG_SYS_CACHELINE_SIZE:
3884 Cache Line Size of the CPU.
3886 - CONFIG_SYS_CCSRBAR_DEFAULT:
3887 Default (power-on reset) physical address of CCSR on Freescale
3890 - CONFIG_SYS_CCSRBAR:
3891 Virtual address of CCSR. On a 32-bit build, this is typically
3892 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3894 - CONFIG_SYS_CCSRBAR_PHYS:
3895 Physical address of CCSR. CCSR can be relocated to a new
3896 physical address, if desired. In this case, this macro should
3897 be set to that address. Otherwise, it should be set to the
3898 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3899 is typically relocated on 36-bit builds. It is recommended
3900 that this macro be defined via the _HIGH and _LOW macros:
3902 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3903 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3905 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3906 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3907 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3908 used in assembly code, so it must not contain typecasts or
3909 integer size suffixes (e.g. "ULL").
3911 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3912 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3913 used in assembly code, so it must not contain typecasts or
3914 integer size suffixes (e.g. "ULL").
3916 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3917 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3918 forced to a value that ensures that CCSR is not relocated.
3920 - Floppy Disk Support:
3921 CONFIG_SYS_FDC_DRIVE_NUMBER
3923 the default drive number (default value 0)
3925 CONFIG_SYS_ISA_IO_STRIDE
3927 defines the spacing between FDC chipset registers
3930 CONFIG_SYS_ISA_IO_OFFSET
3932 defines the offset of register from address. It
3933 depends on which part of the data bus is connected to
3934 the FDC chipset. (default value 0)
3936 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3937 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3940 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3941 fdc_hw_init() is called at the beginning of the FDC
3942 setup. fdc_hw_init() must be provided by the board
3943 source code. It is used to make hardware-dependent
3947 Most IDE controllers were designed to be connected with PCI
3948 interface. Only few of them were designed for AHB interface.
3949 When software is doing ATA command and data transfer to
3950 IDE devices through IDE-AHB controller, some additional
3951 registers accessing to these kind of IDE-AHB controller
3954 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3955 DO NOT CHANGE unless you know exactly what you're
3956 doing! (11-4) [MPC8xx systems only]
3958 - CONFIG_SYS_INIT_RAM_ADDR:
3960 Start address of memory area that can be used for
3961 initial data and stack; please note that this must be
3962 writable memory that is working WITHOUT special
3963 initialization, i. e. you CANNOT use normal RAM which
3964 will become available only after programming the
3965 memory controller and running certain initialization
3968 U-Boot uses the following memory types:
3969 - MPC8xx: IMMR (internal memory of the CPU)
3971 - CONFIG_SYS_GBL_DATA_OFFSET:
3973 Offset of the initial data structure in the memory
3974 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3975 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3976 data is located at the end of the available space
3977 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3978 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3979 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3980 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3983 On the MPC824X (or other systems that use the data
3984 cache for initial memory) the address chosen for
3985 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3986 point to an otherwise UNUSED address space between
3987 the top of RAM and the start of the PCI space.
3989 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3991 - CONFIG_SYS_OR_TIMING_SDRAM:
3994 - CONFIG_SYS_MAMR_PTA:
3995 periodic timer for refresh
3997 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3998 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3999 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4000 CONFIG_SYS_BR1_PRELIM:
4001 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4003 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4004 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4005 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4006 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4008 - CONFIG_PCI_ENUM_ONLY
4009 Only scan through and get the devices on the buses.
4010 Don't do any setup work, presumably because someone or
4011 something has already done it, and we don't need to do it
4012 a second time. Useful for platforms that are pre-booted
4013 by coreboot or similar.
4015 - CONFIG_PCI_INDIRECT_BRIDGE:
4016 Enable support for indirect PCI bridges.
4019 Chip has SRIO or not
4022 Board has SRIO 1 port available
4025 Board has SRIO 2 port available
4027 - CONFIG_SRIO_PCIE_BOOT_MASTER
4028 Board can support master function for Boot from SRIO and PCIE
4030 - CONFIG_SYS_SRIOn_MEM_VIRT:
4031 Virtual Address of SRIO port 'n' memory region
4033 - CONFIG_SYS_SRIOn_MEM_PHYS:
4034 Physical Address of SRIO port 'n' memory region
4036 - CONFIG_SYS_SRIOn_MEM_SIZE:
4037 Size of SRIO port 'n' memory region
4039 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4040 Defined to tell the NAND controller that the NAND chip is using
4042 Not all NAND drivers use this symbol.
4043 Example of drivers that use it:
4044 - drivers/mtd/nand/ndfc.c
4045 - drivers/mtd/nand/mxc_nand.c
4047 - CONFIG_SYS_NDFC_EBC0_CFG
4048 Sets the EBC0_CFG register for the NDFC. If not defined
4049 a default value will be used.
4052 Get DDR timing information from an I2C EEPROM. Common
4053 with pluggable memory modules such as SODIMMs
4056 I2C address of the SPD EEPROM
4058 - CONFIG_SYS_SPD_BUS_NUM
4059 If SPD EEPROM is on an I2C bus other than the first
4060 one, specify here. Note that the value must resolve
4061 to something your driver can deal with.
4063 - CONFIG_SYS_DDR_RAW_TIMING
4064 Get DDR timing information from other than SPD. Common with
4065 soldered DDR chips onboard without SPD. DDR raw timing
4066 parameters are extracted from datasheet and hard-coded into
4067 header files or board specific files.
4069 - CONFIG_FSL_DDR_INTERACTIVE
4070 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4072 - CONFIG_FSL_DDR_SYNC_REFRESH
4073 Enable sync of refresh for multiple controllers.
4075 - CONFIG_FSL_DDR_BIST
4076 Enable built-in memory test for Freescale DDR controllers.
4078 - CONFIG_SYS_83XX_DDR_USES_CS0
4079 Only for 83xx systems. If specified, then DDR should
4080 be configured using CS0 and CS1 instead of CS2 and CS3.
4083 Enable RMII mode for all FECs.
4084 Note that this is a global option, we can't
4085 have one FEC in standard MII mode and another in RMII mode.
4087 - CONFIG_CRC32_VERIFY
4088 Add a verify option to the crc32 command.
4091 => crc32 -v <address> <count> <crc32>
4093 Where address/count indicate a memory area
4094 and crc32 is the correct crc32 which the
4098 Add the "loopw" memory command. This only takes effect if
4099 the memory commands are activated globally (CONFIG_CMD_MEM).
4102 Add the "mdc" and "mwc" memory commands. These are cyclic
4107 This command will print 4 bytes (10,11,12,13) each 500 ms.
4109 => mwc.l 100 12345678 10
4110 This command will write 12345678 to address 100 all 10 ms.
4112 This only takes effect if the memory commands are activated
4113 globally (CONFIG_CMD_MEM).
4115 - CONFIG_SKIP_LOWLEVEL_INIT
4116 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4117 low level initializations (like setting up the memory
4118 controller) are omitted and/or U-Boot does not
4119 relocate itself into RAM.
4121 Normally this variable MUST NOT be defined. The only
4122 exception is when U-Boot is loaded (to RAM) by some
4123 other boot loader or by a debugger which performs
4124 these initializations itself.
4126 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4127 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4128 to be skipped. The normal CP15 init (such as enabling the
4129 instruction cache) is still performed.
4132 Modifies the behaviour of start.S when compiling a loader
4133 that is executed before the actual U-Boot. E.g. when
4134 compiling a NAND SPL.
4137 Modifies the behaviour of start.S when compiling a loader
4138 that is executed after the SPL and before the actual U-Boot.
4139 It is loaded by the SPL.
4141 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4142 Only for 85xx systems. If this variable is specified, the section
4143 .resetvec is not kept and the section .bootpg is placed in the
4144 previous 4k of the .text section.
4146 - CONFIG_ARCH_MAP_SYSMEM
4147 Generally U-Boot (and in particular the md command) uses
4148 effective address. It is therefore not necessary to regard
4149 U-Boot address as virtual addresses that need to be translated
4150 to physical addresses. However, sandbox requires this, since
4151 it maintains its own little RAM buffer which contains all
4152 addressable memory. This option causes some memory accesses
4153 to be mapped through map_sysmem() / unmap_sysmem().
4155 - CONFIG_X86_RESET_VECTOR
4156 If defined, the x86 reset vector code is included. This is not
4157 needed when U-Boot is running from Coreboot.
4159 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4160 Enables the RTC32K OSC on AM33xx based plattforms
4162 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4163 Option to disable subpage write in NAND driver
4164 driver that uses this:
4165 drivers/mtd/nand/davinci_nand.c
4167 Freescale QE/FMAN Firmware Support:
4168 -----------------------------------
4170 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4171 loading of "firmware", which is encoded in the QE firmware binary format.
4172 This firmware often needs to be loaded during U-Boot booting, so macros
4173 are used to identify the storage device (NOR flash, SPI, etc) and the address
4176 - CONFIG_SYS_FMAN_FW_ADDR
4177 The address in the storage device where the FMAN microcode is located. The
4178 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4181 - CONFIG_SYS_QE_FW_ADDR
4182 The address in the storage device where the QE microcode is located. The
4183 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4186 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4187 The maximum possible size of the firmware. The firmware binary format
4188 has a field that specifies the actual size of the firmware, but it
4189 might not be possible to read any part of the firmware unless some
4190 local storage is allocated to hold the entire firmware first.
4192 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4193 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4194 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4195 virtual address in NOR flash.
4197 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4198 Specifies that QE/FMAN firmware is located in NAND flash.
4199 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4201 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4202 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4203 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4205 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4206 Specifies that QE/FMAN firmware is located in the remote (master)
4207 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4208 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4209 window->master inbound window->master LAW->the ucode address in
4210 master's memory space.
4212 Freescale Layerscape Management Complex Firmware Support:
4213 ---------------------------------------------------------
4214 The Freescale Layerscape Management Complex (MC) supports the loading of
4216 This firmware often needs to be loaded during U-Boot booting, so macros
4217 are used to identify the storage device (NOR flash, SPI, etc) and the address
4220 - CONFIG_FSL_MC_ENET
4221 Enable the MC driver for Layerscape SoCs.
4223 Freescale Layerscape Debug Server Support:
4224 -------------------------------------------
4225 The Freescale Layerscape Debug Server Support supports the loading of
4226 "Debug Server firmware" and triggering SP boot-rom.
4227 This firmware often needs to be loaded during U-Boot booting.
4229 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4230 Define alignment of reserved memory MC requires
4235 In order to achieve reproducible builds, timestamps used in the U-Boot build
4236 process have to be set to a fixed value.
4238 This is done using the SOURCE_DATE_EPOCH environment variable.
4239 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4240 option for U-Boot or an environment variable in U-Boot.
4242 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4244 Building the Software:
4245 ======================
4247 Building U-Boot has been tested in several native build environments
4248 and in many different cross environments. Of course we cannot support
4249 all possibly existing versions of cross development tools in all
4250 (potentially obsolete) versions. In case of tool chain problems we
4251 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4252 which is extensively used to build and test U-Boot.
4254 If you are not using a native environment, it is assumed that you
4255 have GNU cross compiling tools available in your path. In this case,
4256 you must set the environment variable CROSS_COMPILE in your shell.
4257 Note that no changes to the Makefile or any other source files are
4258 necessary. For example using the ELDK on a 4xx CPU, please enter:
4260 $ CROSS_COMPILE=ppc_4xx-
4261 $ export CROSS_COMPILE
4263 Note: If you wish to generate Windows versions of the utilities in
4264 the tools directory you can use the MinGW toolchain
4265 (http://www.mingw.org). Set your HOST tools to the MinGW
4266 toolchain and execute 'make tools'. For example:
4268 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4270 Binaries such as tools/mkimage.exe will be created which can
4271 be executed on computers running Windows.
4273 U-Boot is intended to be simple to build. After installing the
4274 sources you must configure U-Boot for one specific board type. This
4279 where "NAME_defconfig" is the name of one of the existing configu-
4280 rations; see boards.cfg for supported names.
4282 Note: for some board special configuration names may exist; check if
4283 additional information is available from the board vendor; for
4284 instance, the TQM823L systems are available without (standard)
4285 or with LCD support. You can select such additional "features"
4286 when choosing the configuration, i. e.
4288 make TQM823L_defconfig
4289 - will configure for a plain TQM823L, i. e. no LCD support
4291 make TQM823L_LCD_defconfig
4292 - will configure for a TQM823L with U-Boot console on LCD
4297 Finally, type "make all", and you should get some working U-Boot
4298 images ready for download to / installation on your system:
4300 - "u-boot.bin" is a raw binary image
4301 - "u-boot" is an image in ELF binary format
4302 - "u-boot.srec" is in Motorola S-Record format
4304 By default the build is performed locally and the objects are saved
4305 in the source directory. One of the two methods can be used to change
4306 this behavior and build U-Boot to some external directory:
4308 1. Add O= to the make command line invocations:
4310 make O=/tmp/build distclean
4311 make O=/tmp/build NAME_defconfig
4312 make O=/tmp/build all
4314 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4316 export KBUILD_OUTPUT=/tmp/build
4321 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4325 Please be aware that the Makefiles assume you are using GNU make, so
4326 for instance on NetBSD you might need to use "gmake" instead of
4330 If the system board that you have is not listed, then you will need
4331 to port U-Boot to your hardware platform. To do this, follow these
4334 1. Create a new directory to hold your board specific code. Add any
4335 files you need. In your board directory, you will need at least
4336 the "Makefile" and a "<board>.c".
4337 2. Create a new configuration file "include/configs/<board>.h" for
4339 3. If you're porting U-Boot to a new CPU, then also create a new
4340 directory to hold your CPU specific code. Add any files you need.
4341 4. Run "make <board>_defconfig" with your new name.
4342 5. Type "make", and you should get a working "u-boot.srec" file
4343 to be installed on your target system.
4344 6. Debug and solve any problems that might arise.
4345 [Of course, this last step is much harder than it sounds.]
4348 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4349 ==============================================================
4351 If you have modified U-Boot sources (for instance added a new board
4352 or support for new devices, a new CPU, etc.) you are expected to
4353 provide feedback to the other developers. The feedback normally takes
4354 the form of a "patch", i. e. a context diff against a certain (latest
4355 official or latest in the git repository) version of U-Boot sources.
4357 But before you submit such a patch, please verify that your modifi-
4358 cation did not break existing code. At least make sure that *ALL* of
4359 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4360 just run the buildman script (tools/buildman/buildman), which will
4361 configure and build U-Boot for ALL supported system. Be warned, this
4362 will take a while. Please see the buildman README, or run 'buildman -H'
4366 See also "U-Boot Porting Guide" below.
4369 Monitor Commands - Overview:
4370 ============================
4372 go - start application at address 'addr'
4373 run - run commands in an environment variable
4374 bootm - boot application image from memory
4375 bootp - boot image via network using BootP/TFTP protocol
4376 bootz - boot zImage from memory
4377 tftpboot- boot image via network using TFTP protocol
4378 and env variables "ipaddr" and "serverip"
4379 (and eventually "gatewayip")
4380 tftpput - upload a file via network using TFTP protocol
4381 rarpboot- boot image via network using RARP/TFTP protocol
4382 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4383 loads - load S-Record file over serial line
4384 loadb - load binary file over serial line (kermit mode)
4386 mm - memory modify (auto-incrementing)
4387 nm - memory modify (constant address)
4388 mw - memory write (fill)
4390 cmp - memory compare
4391 crc32 - checksum calculation
4392 i2c - I2C sub-system
4393 sspi - SPI utility commands
4394 base - print or set address offset
4395 printenv- print environment variables
4396 setenv - set environment variables
4397 saveenv - save environment variables to persistent storage
4398 protect - enable or disable FLASH write protection
4399 erase - erase FLASH memory
4400 flinfo - print FLASH memory information
4401 nand - NAND memory operations (see doc/README.nand)
4402 bdinfo - print Board Info structure
4403 iminfo - print header information for application image
4404 coninfo - print console devices and informations
4405 ide - IDE sub-system
4406 loop - infinite loop on address range
4407 loopw - infinite write loop on address range
4408 mtest - simple RAM test
4409 icache - enable or disable instruction cache
4410 dcache - enable or disable data cache
4411 reset - Perform RESET of the CPU
4412 echo - echo args to console
4413 version - print monitor version
4414 help - print online help
4415 ? - alias for 'help'
4418 Monitor Commands - Detailed Description:
4419 ========================================
4423 For now: just type "help <command>".
4426 Environment Variables:
4427 ======================
4429 U-Boot supports user configuration using Environment Variables which
4430 can be made persistent by saving to Flash memory.
4432 Environment Variables are set using "setenv", printed using
4433 "printenv", and saved to Flash using "saveenv". Using "setenv"
4434 without a value can be used to delete a variable from the
4435 environment. As long as you don't save the environment you are
4436 working with an in-memory copy. In case the Flash area containing the
4437 environment is erased by accident, a default environment is provided.
4439 Some configuration options can be set using Environment Variables.
4441 List of environment variables (most likely not complete):
4443 baudrate - see CONFIG_BAUDRATE
4445 bootdelay - see CONFIG_BOOTDELAY
4447 bootcmd - see CONFIG_BOOTCOMMAND
4449 bootargs - Boot arguments when booting an RTOS image
4451 bootfile - Name of the image to load with TFTP
4453 bootm_low - Memory range available for image processing in the bootm
4454 command can be restricted. This variable is given as
4455 a hexadecimal number and defines lowest address allowed
4456 for use by the bootm command. See also "bootm_size"
4457 environment variable. Address defined by "bootm_low" is
4458 also the base of the initial memory mapping for the Linux
4459 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4462 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4463 This variable is given as a hexadecimal number and it
4464 defines the size of the memory region starting at base
4465 address bootm_low that is accessible by the Linux kernel
4466 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4467 as the default value if it is defined, and bootm_size is
4470 bootm_size - Memory range available for image processing in the bootm
4471 command can be restricted. This variable is given as
4472 a hexadecimal number and defines the size of the region
4473 allowed for use by the bootm command. See also "bootm_low"
4474 environment variable.
4476 updatefile - Location of the software update file on a TFTP server, used
4477 by the automatic software update feature. Please refer to
4478 documentation in doc/README.update for more details.
4480 autoload - if set to "no" (any string beginning with 'n'),
4481 "bootp" will just load perform a lookup of the
4482 configuration from the BOOTP server, but not try to
4483 load any image using TFTP
4485 autostart - if set to "yes", an image loaded using the "bootp",
4486 "rarpboot", "tftpboot" or "diskboot" commands will
4487 be automatically started (by internally calling
4490 If set to "no", a standalone image passed to the
4491 "bootm" command will be copied to the load address
4492 (and eventually uncompressed), but NOT be started.
4493 This can be used to load and uncompress arbitrary
4496 fdt_high - if set this restricts the maximum address that the
4497 flattened device tree will be copied into upon boot.
4498 For example, if you have a system with 1 GB memory
4499 at physical address 0x10000000, while Linux kernel
4500 only recognizes the first 704 MB as low memory, you
4501 may need to set fdt_high as 0x3C000000 to have the
4502 device tree blob be copied to the maximum address
4503 of the 704 MB low memory, so that Linux kernel can
4504 access it during the boot procedure.
4506 If this is set to the special value 0xFFFFFFFF then
4507 the fdt will not be copied at all on boot. For this
4508 to work it must reside in writable memory, have
4509 sufficient padding on the end of it for u-boot to
4510 add the information it needs into it, and the memory
4511 must be accessible by the kernel.
4513 fdtcontroladdr- if set this is the address of the control flattened
4514 device tree used by U-Boot when CONFIG_OF_CONTROL is
4517 i2cfast - (PPC405GP|PPC405EP only)
4518 if set to 'y' configures Linux I2C driver for fast
4519 mode (400kHZ). This environment variable is used in
4520 initialization code. So, for changes to be effective
4521 it must be saved and board must be reset.
4523 initrd_high - restrict positioning of initrd images:
4524 If this variable is not set, initrd images will be
4525 copied to the highest possible address in RAM; this
4526 is usually what you want since it allows for
4527 maximum initrd size. If for some reason you want to
4528 make sure that the initrd image is loaded below the
4529 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4530 variable to a value of "no" or "off" or "0".
4531 Alternatively, you can set it to a maximum upper
4532 address to use (U-Boot will still check that it
4533 does not overwrite the U-Boot stack and data).
4535 For instance, when you have a system with 16 MB
4536 RAM, and want to reserve 4 MB from use by Linux,
4537 you can do this by adding "mem=12M" to the value of
4538 the "bootargs" variable. However, now you must make
4539 sure that the initrd image is placed in the first
4540 12 MB as well - this can be done with
4542 setenv initrd_high 00c00000
4544 If you set initrd_high to 0xFFFFFFFF, this is an
4545 indication to U-Boot that all addresses are legal
4546 for the Linux kernel, including addresses in flash
4547 memory. In this case U-Boot will NOT COPY the
4548 ramdisk at all. This may be useful to reduce the
4549 boot time on your system, but requires that this
4550 feature is supported by your Linux kernel.
4552 ipaddr - IP address; needed for tftpboot command
4554 loadaddr - Default load address for commands like "bootp",
4555 "rarpboot", "tftpboot", "loadb" or "diskboot"
4557 loads_echo - see CONFIG_LOADS_ECHO
4559 serverip - TFTP server IP address; needed for tftpboot command
4561 bootretry - see CONFIG_BOOT_RETRY_TIME
4563 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4565 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4567 ethprime - controls which interface is used first.
4569 ethact - controls which interface is currently active.
4570 For example you can do the following
4572 => setenv ethact FEC
4573 => ping 192.168.0.1 # traffic sent on FEC
4574 => setenv ethact SCC
4575 => ping 10.0.0.1 # traffic sent on SCC
4577 ethrotate - When set to "no" U-Boot does not go through all
4578 available network interfaces.
4579 It just stays at the currently selected interface.
4581 netretry - When set to "no" each network operation will
4582 either succeed or fail without retrying.
4583 When set to "once" the network operation will
4584 fail when all the available network interfaces
4585 are tried once without success.
4586 Useful on scripts which control the retry operation
4589 npe_ucode - set load address for the NPE microcode
4591 silent_linux - If set then Linux will be told to boot silently, by
4592 changing the console to be empty. If "yes" it will be
4593 made silent. If "no" it will not be made silent. If
4594 unset, then it will be made silent if the U-Boot console
4597 tftpsrcp - If this is set, the value is used for TFTP's
4600 tftpdstp - If this is set, the value is used for TFTP's UDP
4601 destination port instead of the Well Know Port 69.
4603 tftpblocksize - Block size to use for TFTP transfers; if not set,
4604 we use the TFTP server's default block size
4606 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4607 seconds, minimum value is 1000 = 1 second). Defines
4608 when a packet is considered to be lost so it has to
4609 be retransmitted. The default is 5000 = 5 seconds.
4610 Lowering this value may make downloads succeed
4611 faster in networks with high packet loss rates or
4612 with unreliable TFTP servers.
4614 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4615 unit, minimum value = 0). Defines how many timeouts
4616 can happen during a single file transfer before that
4617 transfer is aborted. The default is 10, and 0 means
4618 'no timeouts allowed'. Increasing this value may help
4619 downloads succeed with high packet loss rates, or with
4620 unreliable TFTP servers or client hardware.
4622 vlan - When set to a value < 4095 the traffic over
4623 Ethernet is encapsulated/received over 802.1q
4626 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4627 Unsigned value, in milliseconds. If not set, the period will
4628 be either the default (28000), or a value based on
4629 CONFIG_NET_RETRY_COUNT, if defined. This value has
4630 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4632 The following image location variables contain the location of images
4633 used in booting. The "Image" column gives the role of the image and is
4634 not an environment variable name. The other columns are environment
4635 variable names. "File Name" gives the name of the file on a TFTP
4636 server, "RAM Address" gives the location in RAM the image will be
4637 loaded to, and "Flash Location" gives the image's address in NOR
4638 flash or offset in NAND flash.
4640 *Note* - these variables don't have to be defined for all boards, some
4641 boards currently use other variables for these purposes, and some
4642 boards use these variables for other purposes.
4644 Image File Name RAM Address Flash Location
4645 ----- --------- ----------- --------------
4646 u-boot u-boot u-boot_addr_r u-boot_addr
4647 Linux kernel bootfile kernel_addr_r kernel_addr
4648 device tree blob fdtfile fdt_addr_r fdt_addr
4649 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4651 The following environment variables may be used and automatically
4652 updated by the network boot commands ("bootp" and "rarpboot"),
4653 depending the information provided by your boot server:
4655 bootfile - see above
4656 dnsip - IP address of your Domain Name Server
4657 dnsip2 - IP address of your secondary Domain Name Server
4658 gatewayip - IP address of the Gateway (Router) to use
4659 hostname - Target hostname
4661 netmask - Subnet Mask
4662 rootpath - Pathname of the root filesystem on the NFS server
4663 serverip - see above
4666 There are two special Environment Variables:
4668 serial# - contains hardware identification information such
4669 as type string and/or serial number
4670 ethaddr - Ethernet address
4672 These variables can be set only once (usually during manufacturing of
4673 the board). U-Boot refuses to delete or overwrite these variables
4674 once they have been set once.
4677 Further special Environment Variables:
4679 ver - Contains the U-Boot version string as printed
4680 with the "version" command. This variable is
4681 readonly (see CONFIG_VERSION_VARIABLE).
4684 Please note that changes to some configuration parameters may take
4685 only effect after the next boot (yes, that's just like Windoze :-).
4688 Callback functions for environment variables:
4689 ---------------------------------------------
4691 For some environment variables, the behavior of u-boot needs to change
4692 when their values are changed. This functionality allows functions to
4693 be associated with arbitrary variables. On creation, overwrite, or
4694 deletion, the callback will provide the opportunity for some side
4695 effect to happen or for the change to be rejected.
4697 The callbacks are named and associated with a function using the
4698 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4700 These callbacks are associated with variables in one of two ways. The
4701 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4702 in the board configuration to a string that defines a list of
4703 associations. The list must be in the following format:
4705 entry = variable_name[:callback_name]
4708 If the callback name is not specified, then the callback is deleted.
4709 Spaces are also allowed anywhere in the list.
4711 Callbacks can also be associated by defining the ".callbacks" variable
4712 with the same list format above. Any association in ".callbacks" will
4713 override any association in the static list. You can define
4714 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4715 ".callbacks" environment variable in the default or embedded environment.
4717 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4718 regular expression. This allows multiple variables to be connected to
4719 the same callback without explicitly listing them all out.
4722 Command Line Parsing:
4723 =====================
4725 There are two different command line parsers available with U-Boot:
4726 the old "simple" one, and the much more powerful "hush" shell:
4728 Old, simple command line parser:
4729 --------------------------------
4731 - supports environment variables (through setenv / saveenv commands)
4732 - several commands on one line, separated by ';'
4733 - variable substitution using "... ${name} ..." syntax
4734 - special characters ('$', ';') can be escaped by prefixing with '\',
4736 setenv bootcmd bootm \${address}
4737 - You can also escape text by enclosing in single apostrophes, for example:
4738 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4743 - similar to Bourne shell, with control structures like
4744 if...then...else...fi, for...do...done; while...do...done,
4745 until...do...done, ...
4746 - supports environment ("global") variables (through setenv / saveenv
4747 commands) and local shell variables (through standard shell syntax
4748 "name=value"); only environment variables can be used with "run"
4754 (1) If a command line (or an environment variable executed by a "run"
4755 command) contains several commands separated by semicolon, and
4756 one of these commands fails, then the remaining commands will be
4759 (2) If you execute several variables with one call to run (i. e.
4760 calling run with a list of variables as arguments), any failing
4761 command will cause "run" to terminate, i. e. the remaining
4762 variables are not executed.
4764 Note for Redundant Ethernet Interfaces:
4765 =======================================
4767 Some boards come with redundant Ethernet interfaces; U-Boot supports
4768 such configurations and is capable of automatic selection of a
4769 "working" interface when needed. MAC assignment works as follows:
4771 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4772 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4773 "eth1addr" (=>eth1), "eth2addr", ...
4775 If the network interface stores some valid MAC address (for instance
4776 in SROM), this is used as default address if there is NO correspon-
4777 ding setting in the environment; if the corresponding environment
4778 variable is set, this overrides the settings in the card; that means:
4780 o If the SROM has a valid MAC address, and there is no address in the
4781 environment, the SROM's address is used.
4783 o If there is no valid address in the SROM, and a definition in the
4784 environment exists, then the value from the environment variable is
4787 o If both the SROM and the environment contain a MAC address, and
4788 both addresses are the same, this MAC address is used.
4790 o If both the SROM and the environment contain a MAC address, and the
4791 addresses differ, the value from the environment is used and a
4794 o If neither SROM nor the environment contain a MAC address, an error
4795 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4796 a random, locally-assigned MAC is used.
4798 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4799 will be programmed into hardware as part of the initialization process. This
4800 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4801 The naming convention is as follows:
4802 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4807 U-Boot is capable of booting (and performing other auxiliary operations on)
4808 images in two formats:
4810 New uImage format (FIT)
4811 -----------------------
4813 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4814 to Flattened Device Tree). It allows the use of images with multiple
4815 components (several kernels, ramdisks, etc.), with contents protected by
4816 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4822 Old image format is based on binary files which can be basically anything,
4823 preceded by a special header; see the definitions in include/image.h for
4824 details; basically, the header defines the following image properties:
4826 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4827 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4828 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4829 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4831 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4832 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4833 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4834 * Compression Type (uncompressed, gzip, bzip2)
4840 The header is marked by a special Magic Number, and both the header
4841 and the data portions of the image are secured against corruption by
4848 Although U-Boot should support any OS or standalone application
4849 easily, the main focus has always been on Linux during the design of
4852 U-Boot includes many features that so far have been part of some
4853 special "boot loader" code within the Linux kernel. Also, any
4854 "initrd" images to be used are no longer part of one big Linux image;
4855 instead, kernel and "initrd" are separate images. This implementation
4856 serves several purposes:
4858 - the same features can be used for other OS or standalone
4859 applications (for instance: using compressed images to reduce the
4860 Flash memory footprint)
4862 - it becomes much easier to port new Linux kernel versions because
4863 lots of low-level, hardware dependent stuff are done by U-Boot
4865 - the same Linux kernel image can now be used with different "initrd"
4866 images; of course this also means that different kernel images can
4867 be run with the same "initrd". This makes testing easier (you don't
4868 have to build a new "zImage.initrd" Linux image when you just
4869 change a file in your "initrd"). Also, a field-upgrade of the
4870 software is easier now.
4876 Porting Linux to U-Boot based systems:
4877 ---------------------------------------
4879 U-Boot cannot save you from doing all the necessary modifications to
4880 configure the Linux device drivers for use with your target hardware
4881 (no, we don't intend to provide a full virtual machine interface to
4884 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4886 Just make sure your machine specific header file (for instance
4887 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4888 Information structure as we define in include/asm-<arch>/u-boot.h,
4889 and make sure that your definition of IMAP_ADDR uses the same value
4890 as your U-Boot configuration in CONFIG_SYS_IMMR.
4892 Note that U-Boot now has a driver model, a unified model for drivers.
4893 If you are adding a new driver, plumb it into driver model. If there
4894 is no uclass available, you are encouraged to create one. See
4898 Configuring the Linux kernel:
4899 -----------------------------
4901 No specific requirements for U-Boot. Make sure you have some root
4902 device (initial ramdisk, NFS) for your target system.
4905 Building a Linux Image:
4906 -----------------------
4908 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4909 not used. If you use recent kernel source, a new build target
4910 "uImage" will exist which automatically builds an image usable by
4911 U-Boot. Most older kernels also have support for a "pImage" target,
4912 which was introduced for our predecessor project PPCBoot and uses a
4913 100% compatible format.
4917 make TQM850L_defconfig
4922 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4923 encapsulate a compressed Linux kernel image with header information,
4924 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4926 * build a standard "vmlinux" kernel image (in ELF binary format):
4928 * convert the kernel into a raw binary image:
4930 ${CROSS_COMPILE}-objcopy -O binary \
4931 -R .note -R .comment \
4932 -S vmlinux linux.bin
4934 * compress the binary image:
4938 * package compressed binary image for U-Boot:
4940 mkimage -A ppc -O linux -T kernel -C gzip \
4941 -a 0 -e 0 -n "Linux Kernel Image" \
4942 -d linux.bin.gz uImage
4945 The "mkimage" tool can also be used to create ramdisk images for use
4946 with U-Boot, either separated from the Linux kernel image, or
4947 combined into one file. "mkimage" encapsulates the images with a 64
4948 byte header containing information about target architecture,
4949 operating system, image type, compression method, entry points, time
4950 stamp, CRC32 checksums, etc.
4952 "mkimage" can be called in two ways: to verify existing images and
4953 print the header information, or to build new images.
4955 In the first form (with "-l" option) mkimage lists the information
4956 contained in the header of an existing U-Boot image; this includes
4957 checksum verification:
4959 tools/mkimage -l image
4960 -l ==> list image header information
4962 The second form (with "-d" option) is used to build a U-Boot image
4963 from a "data file" which is used as image payload:
4965 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4966 -n name -d data_file image
4967 -A ==> set architecture to 'arch'
4968 -O ==> set operating system to 'os'
4969 -T ==> set image type to 'type'
4970 -C ==> set compression type 'comp'
4971 -a ==> set load address to 'addr' (hex)
4972 -e ==> set entry point to 'ep' (hex)
4973 -n ==> set image name to 'name'
4974 -d ==> use image data from 'datafile'
4976 Right now, all Linux kernels for PowerPC systems use the same load
4977 address (0x00000000), but the entry point address depends on the
4980 - 2.2.x kernels have the entry point at 0x0000000C,
4981 - 2.3.x and later kernels have the entry point at 0x00000000.
4983 So a typical call to build a U-Boot image would read:
4985 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4986 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4987 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4988 > examples/uImage.TQM850L
4989 Image Name: 2.4.4 kernel for TQM850L
4990 Created: Wed Jul 19 02:34:59 2000
4991 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4992 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4993 Load Address: 0x00000000
4994 Entry Point: 0x00000000
4996 To verify the contents of the image (or check for corruption):
4998 -> tools/mkimage -l examples/uImage.TQM850L
4999 Image Name: 2.4.4 kernel for TQM850L
5000 Created: Wed Jul 19 02:34:59 2000
5001 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5002 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5003 Load Address: 0x00000000
5004 Entry Point: 0x00000000
5006 NOTE: for embedded systems where boot time is critical you can trade
5007 speed for memory and install an UNCOMPRESSED image instead: this
5008 needs more space in Flash, but boots much faster since it does not
5009 need to be uncompressed:
5011 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5012 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5013 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5014 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5015 > examples/uImage.TQM850L-uncompressed
5016 Image Name: 2.4.4 kernel for TQM850L
5017 Created: Wed Jul 19 02:34:59 2000
5018 Image Type: PowerPC Linux Kernel Image (uncompressed)
5019 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5020 Load Address: 0x00000000
5021 Entry Point: 0x00000000
5024 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5025 when your kernel is intended to use an initial ramdisk:
5027 -> tools/mkimage -n 'Simple Ramdisk Image' \
5028 > -A ppc -O linux -T ramdisk -C gzip \
5029 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5030 Image Name: Simple Ramdisk Image
5031 Created: Wed Jan 12 14:01:50 2000
5032 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5033 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5034 Load Address: 0x00000000
5035 Entry Point: 0x00000000
5037 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5038 option performs the converse operation of the mkimage's second form (the "-d"
5039 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5042 tools/dumpimage -i image -T type -p position data_file
5043 -i ==> extract from the 'image' a specific 'data_file'
5044 -T ==> set image type to 'type'
5045 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5048 Installing a Linux Image:
5049 -------------------------
5051 To downloading a U-Boot image over the serial (console) interface,
5052 you must convert the image to S-Record format:
5054 objcopy -I binary -O srec examples/image examples/image.srec
5056 The 'objcopy' does not understand the information in the U-Boot
5057 image header, so the resulting S-Record file will be relative to
5058 address 0x00000000. To load it to a given address, you need to
5059 specify the target address as 'offset' parameter with the 'loads'
5062 Example: install the image to address 0x40100000 (which on the
5063 TQM8xxL is in the first Flash bank):
5065 => erase 40100000 401FFFFF
5071 ## Ready for S-Record download ...
5072 ~>examples/image.srec
5073 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5075 15989 15990 15991 15992
5076 [file transfer complete]
5078 ## Start Addr = 0x00000000
5081 You can check the success of the download using the 'iminfo' command;
5082 this includes a checksum verification so you can be sure no data
5083 corruption happened:
5087 ## Checking Image at 40100000 ...
5088 Image Name: 2.2.13 for initrd on TQM850L
5089 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5090 Data Size: 335725 Bytes = 327 kB = 0 MB
5091 Load Address: 00000000
5092 Entry Point: 0000000c
5093 Verifying Checksum ... OK
5099 The "bootm" command is used to boot an application that is stored in
5100 memory (RAM or Flash). In case of a Linux kernel image, the contents
5101 of the "bootargs" environment variable is passed to the kernel as
5102 parameters. You can check and modify this variable using the
5103 "printenv" and "setenv" commands:
5106 => printenv bootargs
5107 bootargs=root=/dev/ram
5109 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5111 => printenv bootargs
5112 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5115 ## Booting Linux kernel at 40020000 ...
5116 Image Name: 2.2.13 for NFS on TQM850L
5117 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5118 Data Size: 381681 Bytes = 372 kB = 0 MB
5119 Load Address: 00000000
5120 Entry Point: 0000000c
5121 Verifying Checksum ... OK
5122 Uncompressing Kernel Image ... OK
5123 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
5124 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5125 time_init: decrementer frequency = 187500000/60
5126 Calibrating delay loop... 49.77 BogoMIPS
5127 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5130 If you want to boot a Linux kernel with initial RAM disk, you pass
5131 the memory addresses of both the kernel and the initrd image (PPBCOOT
5132 format!) to the "bootm" command:
5134 => imi 40100000 40200000
5136 ## Checking Image at 40100000 ...
5137 Image Name: 2.2.13 for initrd on TQM850L
5138 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5139 Data Size: 335725 Bytes = 327 kB = 0 MB
5140 Load Address: 00000000
5141 Entry Point: 0000000c
5142 Verifying Checksum ... OK
5144 ## Checking Image at 40200000 ...
5145 Image Name: Simple Ramdisk Image
5146 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5147 Data Size: 566530 Bytes = 553 kB = 0 MB
5148 Load Address: 00000000
5149 Entry Point: 00000000
5150 Verifying Checksum ... OK
5152 => bootm 40100000 40200000
5153 ## Booting Linux kernel at 40100000 ...
5154 Image Name: 2.2.13 for initrd on TQM850L
5155 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5156 Data Size: 335725 Bytes = 327 kB = 0 MB
5157 Load Address: 00000000
5158 Entry Point: 0000000c
5159 Verifying Checksum ... OK
5160 Uncompressing Kernel Image ... OK
5161 ## Loading RAMDisk Image at 40200000 ...
5162 Image Name: Simple Ramdisk Image
5163 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5164 Data Size: 566530 Bytes = 553 kB = 0 MB
5165 Load Address: 00000000
5166 Entry Point: 00000000
5167 Verifying Checksum ... OK
5168 Loading Ramdisk ... OK
5169 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
5170 Boot arguments: root=/dev/ram
5171 time_init: decrementer frequency = 187500000/60
5172 Calibrating delay loop... 49.77 BogoMIPS
5174 RAMDISK: Compressed image found at block 0
5175 VFS: Mounted root (ext2 filesystem).
5179 Boot Linux and pass a flat device tree:
5182 First, U-Boot must be compiled with the appropriate defines. See the section
5183 titled "Linux Kernel Interface" above for a more in depth explanation. The
5184 following is an example of how to start a kernel and pass an updated
5190 oft=oftrees/mpc8540ads.dtb
5191 => tftp $oftaddr $oft
5192 Speed: 1000, full duplex
5194 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5195 Filename 'oftrees/mpc8540ads.dtb'.
5196 Load address: 0x300000
5199 Bytes transferred = 4106 (100a hex)
5200 => tftp $loadaddr $bootfile
5201 Speed: 1000, full duplex
5203 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5205 Load address: 0x200000
5206 Loading:############
5208 Bytes transferred = 1029407 (fb51f hex)
5213 => bootm $loadaddr - $oftaddr
5214 ## Booting image at 00200000 ...
5215 Image Name: Linux-2.6.17-dirty
5216 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5217 Data Size: 1029343 Bytes = 1005.2 kB
5218 Load Address: 00000000
5219 Entry Point: 00000000
5220 Verifying Checksum ... OK
5221 Uncompressing Kernel Image ... OK
5222 Booting using flat device tree at 0x300000
5223 Using MPC85xx ADS machine description
5224 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5228 More About U-Boot Image Types:
5229 ------------------------------
5231 U-Boot supports the following image types:
5233 "Standalone Programs" are directly runnable in the environment
5234 provided by U-Boot; it is expected that (if they behave
5235 well) you can continue to work in U-Boot after return from
5236 the Standalone Program.
5237 "OS Kernel Images" are usually images of some Embedded OS which
5238 will take over control completely. Usually these programs
5239 will install their own set of exception handlers, device
5240 drivers, set up the MMU, etc. - this means, that you cannot
5241 expect to re-enter U-Boot except by resetting the CPU.
5242 "RAMDisk Images" are more or less just data blocks, and their
5243 parameters (address, size) are passed to an OS kernel that is
5245 "Multi-File Images" contain several images, typically an OS
5246 (Linux) kernel image and one or more data images like
5247 RAMDisks. This construct is useful for instance when you want
5248 to boot over the network using BOOTP etc., where the boot
5249 server provides just a single image file, but you want to get
5250 for instance an OS kernel and a RAMDisk image.
5252 "Multi-File Images" start with a list of image sizes, each
5253 image size (in bytes) specified by an "uint32_t" in network
5254 byte order. This list is terminated by an "(uint32_t)0".
5255 Immediately after the terminating 0 follow the images, one by
5256 one, all aligned on "uint32_t" boundaries (size rounded up to
5257 a multiple of 4 bytes).
5259 "Firmware Images" are binary images containing firmware (like
5260 U-Boot or FPGA images) which usually will be programmed to
5263 "Script files" are command sequences that will be executed by
5264 U-Boot's command interpreter; this feature is especially
5265 useful when you configure U-Boot to use a real shell (hush)
5266 as command interpreter.
5268 Booting the Linux zImage:
5269 -------------------------
5271 On some platforms, it's possible to boot Linux zImage. This is done
5272 using the "bootz" command. The syntax of "bootz" command is the same
5273 as the syntax of "bootm" command.
5275 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5276 kernel with raw initrd images. The syntax is slightly different, the
5277 address of the initrd must be augmented by it's size, in the following
5278 format: "<initrd addres>:<initrd size>".
5284 One of the features of U-Boot is that you can dynamically load and
5285 run "standalone" applications, which can use some resources of
5286 U-Boot like console I/O functions or interrupt services.
5288 Two simple examples are included with the sources:
5293 'examples/hello_world.c' contains a small "Hello World" Demo
5294 application; it is automatically compiled when you build U-Boot.
5295 It's configured to run at address 0x00040004, so you can play with it
5299 ## Ready for S-Record download ...
5300 ~>examples/hello_world.srec
5301 1 2 3 4 5 6 7 8 9 10 11 ...
5302 [file transfer complete]
5304 ## Start Addr = 0x00040004
5306 => go 40004 Hello World! This is a test.
5307 ## Starting application at 0x00040004 ...
5318 Hit any key to exit ...
5320 ## Application terminated, rc = 0x0
5322 Another example, which demonstrates how to register a CPM interrupt
5323 handler with the U-Boot code, can be found in 'examples/timer.c'.
5324 Here, a CPM timer is set up to generate an interrupt every second.
5325 The interrupt service routine is trivial, just printing a '.'
5326 character, but this is just a demo program. The application can be
5327 controlled by the following keys:
5329 ? - print current values og the CPM Timer registers
5330 b - enable interrupts and start timer
5331 e - stop timer and disable interrupts
5332 q - quit application
5335 ## Ready for S-Record download ...
5336 ~>examples/timer.srec
5337 1 2 3 4 5 6 7 8 9 10 11 ...
5338 [file transfer complete]
5340 ## Start Addr = 0x00040004
5343 ## Starting application at 0x00040004 ...
5346 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5349 [q, b, e, ?] Set interval 1000000 us
5352 [q, b, e, ?] ........
5353 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5356 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5359 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5362 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5364 [q, b, e, ?] ...Stopping timer
5366 [q, b, e, ?] ## Application terminated, rc = 0x0
5372 Over time, many people have reported problems when trying to use the
5373 "minicom" terminal emulation program for serial download. I (wd)
5374 consider minicom to be broken, and recommend not to use it. Under
5375 Unix, I recommend to use C-Kermit for general purpose use (and
5376 especially for kermit binary protocol download ("loadb" command), and
5377 use "cu" for S-Record download ("loads" command). See
5378 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5379 for help with kermit.
5382 Nevertheless, if you absolutely want to use it try adding this
5383 configuration to your "File transfer protocols" section:
5385 Name Program Name U/D FullScr IO-Red. Multi
5386 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5387 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5393 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5394 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5396 Building requires a cross environment; it is known to work on
5397 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5398 need gmake since the Makefiles are not compatible with BSD make).
5399 Note that the cross-powerpc package does not install include files;
5400 attempting to build U-Boot will fail because <machine/ansi.h> is
5401 missing. This file has to be installed and patched manually:
5403 # cd /usr/pkg/cross/powerpc-netbsd/include
5405 # ln -s powerpc machine
5406 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5407 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5409 Native builds *don't* work due to incompatibilities between native
5410 and U-Boot include files.
5412 Booting assumes that (the first part of) the image booted is a
5413 stage-2 loader which in turn loads and then invokes the kernel
5414 proper. Loader sources will eventually appear in the NetBSD source
5415 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5416 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5419 Implementation Internals:
5420 =========================
5422 The following is not intended to be a complete description of every
5423 implementation detail. However, it should help to understand the
5424 inner workings of U-Boot and make it easier to port it to custom
5428 Initial Stack, Global Data:
5429 ---------------------------
5431 The implementation of U-Boot is complicated by the fact that U-Boot
5432 starts running out of ROM (flash memory), usually without access to
5433 system RAM (because the memory controller is not initialized yet).
5434 This means that we don't have writable Data or BSS segments, and BSS
5435 is not initialized as zero. To be able to get a C environment working
5436 at all, we have to allocate at least a minimal stack. Implementation
5437 options for this are defined and restricted by the CPU used: Some CPU
5438 models provide on-chip memory (like the IMMR area on MPC8xx and
5439 MPC826x processors), on others (parts of) the data cache can be
5440 locked as (mis-) used as memory, etc.
5442 Chris Hallinan posted a good summary of these issues to the
5443 U-Boot mailing list:
5445 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5446 From: "Chris Hallinan" <clh@net1plus.com>
5447 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5450 Correct me if I'm wrong, folks, but the way I understand it
5451 is this: Using DCACHE as initial RAM for Stack, etc, does not
5452 require any physical RAM backing up the cache. The cleverness
5453 is that the cache is being used as a temporary supply of
5454 necessary storage before the SDRAM controller is setup. It's
5455 beyond the scope of this list to explain the details, but you
5456 can see how this works by studying the cache architecture and
5457 operation in the architecture and processor-specific manuals.
5459 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5460 is another option for the system designer to use as an
5461 initial stack/RAM area prior to SDRAM being available. Either
5462 option should work for you. Using CS 4 should be fine if your
5463 board designers haven't used it for something that would
5464 cause you grief during the initial boot! It is frequently not
5467 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5468 with your processor/board/system design. The default value
5469 you will find in any recent u-boot distribution in
5470 walnut.h should work for you. I'd set it to a value larger
5471 than your SDRAM module. If you have a 64MB SDRAM module, set
5472 it above 400_0000. Just make sure your board has no resources
5473 that are supposed to respond to that address! That code in
5474 start.S has been around a while and should work as is when
5475 you get the config right.
5480 It is essential to remember this, since it has some impact on the C
5481 code for the initialization procedures:
5483 * Initialized global data (data segment) is read-only. Do not attempt
5486 * Do not use any uninitialized global data (or implicitly initialized
5487 as zero data - BSS segment) at all - this is undefined, initiali-
5488 zation is performed later (when relocating to RAM).
5490 * Stack space is very limited. Avoid big data buffers or things like
5493 Having only the stack as writable memory limits means we cannot use
5494 normal global data to share information between the code. But it
5495 turned out that the implementation of U-Boot can be greatly
5496 simplified by making a global data structure (gd_t) available to all
5497 functions. We could pass a pointer to this data as argument to _all_
5498 functions, but this would bloat the code. Instead we use a feature of
5499 the GCC compiler (Global Register Variables) to share the data: we
5500 place a pointer (gd) to the global data into a register which we
5501 reserve for this purpose.
5503 When choosing a register for such a purpose we are restricted by the
5504 relevant (E)ABI specifications for the current architecture, and by
5505 GCC's implementation.
5507 For PowerPC, the following registers have specific use:
5509 R2: reserved for system use
5510 R3-R4: parameter passing and return values
5511 R5-R10: parameter passing
5512 R13: small data area pointer
5516 (U-Boot also uses R12 as internal GOT pointer. r12
5517 is a volatile register so r12 needs to be reset when
5518 going back and forth between asm and C)
5520 ==> U-Boot will use R2 to hold a pointer to the global data
5522 Note: on PPC, we could use a static initializer (since the
5523 address of the global data structure is known at compile time),
5524 but it turned out that reserving a register results in somewhat
5525 smaller code - although the code savings are not that big (on
5526 average for all boards 752 bytes for the whole U-Boot image,
5527 624 text + 127 data).
5529 On ARM, the following registers are used:
5531 R0: function argument word/integer result
5532 R1-R3: function argument word
5533 R9: platform specific
5534 R10: stack limit (used only if stack checking is enabled)
5535 R11: argument (frame) pointer
5536 R12: temporary workspace
5539 R15: program counter
5541 ==> U-Boot will use R9 to hold a pointer to the global data
5543 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5545 On Nios II, the ABI is documented here:
5546 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5548 ==> U-Boot will use gp to hold a pointer to the global data
5550 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5551 to access small data sections, so gp is free.
5553 On NDS32, the following registers are used:
5555 R0-R1: argument/return
5557 R15: temporary register for assembler
5558 R16: trampoline register
5559 R28: frame pointer (FP)
5560 R29: global pointer (GP)
5561 R30: link register (LP)
5562 R31: stack pointer (SP)
5563 PC: program counter (PC)
5565 ==> U-Boot will use R10 to hold a pointer to the global data
5567 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5568 or current versions of GCC may "optimize" the code too much.
5573 U-Boot runs in system state and uses physical addresses, i.e. the
5574 MMU is not used either for address mapping nor for memory protection.
5576 The available memory is mapped to fixed addresses using the memory
5577 controller. In this process, a contiguous block is formed for each
5578 memory type (Flash, SDRAM, SRAM), even when it consists of several
5579 physical memory banks.
5581 U-Boot is installed in the first 128 kB of the first Flash bank (on
5582 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5583 booting and sizing and initializing DRAM, the code relocates itself
5584 to the upper end of DRAM. Immediately below the U-Boot code some
5585 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5586 configuration setting]. Below that, a structure with global Board
5587 Info data is placed, followed by the stack (growing downward).
5589 Additionally, some exception handler code is copied to the low 8 kB
5590 of DRAM (0x00000000 ... 0x00001FFF).
5592 So a typical memory configuration with 16 MB of DRAM could look like
5595 0x0000 0000 Exception Vector code
5598 0x0000 2000 Free for Application Use
5604 0x00FB FF20 Monitor Stack (Growing downward)
5605 0x00FB FFAC Board Info Data and permanent copy of global data
5606 0x00FC 0000 Malloc Arena
5609 0x00FE 0000 RAM Copy of Monitor Code
5610 ... eventually: LCD or video framebuffer
5611 ... eventually: pRAM (Protected RAM - unchanged by reset)
5612 0x00FF FFFF [End of RAM]
5615 System Initialization:
5616 ----------------------
5618 In the reset configuration, U-Boot starts at the reset entry point
5619 (on most PowerPC systems at address 0x00000100). Because of the reset
5620 configuration for CS0# this is a mirror of the on board Flash memory.
5621 To be able to re-map memory U-Boot then jumps to its link address.
5622 To be able to implement the initialization code in C, a (small!)
5623 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5624 which provide such a feature like), or in a locked part of the data
5625 cache. After that, U-Boot initializes the CPU core, the caches and
5628 Next, all (potentially) available memory banks are mapped using a
5629 preliminary mapping. For example, we put them on 512 MB boundaries
5630 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5631 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5632 programmed for SDRAM access. Using the temporary configuration, a
5633 simple memory test is run that determines the size of the SDRAM
5636 When there is more than one SDRAM bank, and the banks are of
5637 different size, the largest is mapped first. For equal size, the first
5638 bank (CS2#) is mapped first. The first mapping is always for address
5639 0x00000000, with any additional banks following immediately to create
5640 contiguous memory starting from 0.
5642 Then, the monitor installs itself at the upper end of the SDRAM area
5643 and allocates memory for use by malloc() and for the global Board
5644 Info data; also, the exception vector code is copied to the low RAM
5645 pages, and the final stack is set up.
5647 Only after this relocation will you have a "normal" C environment;
5648 until that you are restricted in several ways, mostly because you are
5649 running from ROM, and because the code will have to be relocated to a
5653 U-Boot Porting Guide:
5654 ----------------------
5656 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5660 int main(int argc, char *argv[])
5662 sighandler_t no_more_time;
5664 signal(SIGALRM, no_more_time);
5665 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5667 if (available_money > available_manpower) {
5668 Pay consultant to port U-Boot;
5672 Download latest U-Boot source;
5674 Subscribe to u-boot mailing list;
5677 email("Hi, I am new to U-Boot, how do I get started?");
5680 Read the README file in the top level directory;
5681 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5682 Read applicable doc/*.README;
5683 Read the source, Luke;
5684 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5687 if (available_money > toLocalCurrency ($2500))
5690 Add a lot of aggravation and time;
5692 if (a similar board exists) { /* hopefully... */
5693 cp -a board/<similar> board/<myboard>
5694 cp include/configs/<similar>.h include/configs/<myboard>.h
5696 Create your own board support subdirectory;
5697 Create your own board include/configs/<myboard>.h file;
5699 Edit new board/<myboard> files
5700 Edit new include/configs/<myboard>.h
5705 Add / modify source code;
5709 email("Hi, I am having problems...");
5711 Send patch file to the U-Boot email list;
5712 if (reasonable critiques)
5713 Incorporate improvements from email list code review;
5715 Defend code as written;
5721 void no_more_time (int sig)
5730 All contributions to U-Boot should conform to the Linux kernel
5731 coding style; see the file "Documentation/CodingStyle" and the script
5732 "scripts/Lindent" in your Linux kernel source directory.
5734 Source files originating from a different project (for example the
5735 MTD subsystem) are generally exempt from these guidelines and are not
5736 reformatted to ease subsequent migration to newer versions of those
5739 Please note that U-Boot is implemented in C (and to some small parts in
5740 Assembler); no C++ is used, so please do not use C++ style comments (//)
5743 Please also stick to the following formatting rules:
5744 - remove any trailing white space
5745 - use TAB characters for indentation and vertical alignment, not spaces
5746 - make sure NOT to use DOS '\r\n' line feeds
5747 - do not add more than 2 consecutive empty lines to source files
5748 - do not add trailing empty lines to source files
5750 Submissions which do not conform to the standards may be returned
5751 with a request to reformat the changes.
5757 Since the number of patches for U-Boot is growing, we need to
5758 establish some rules. Submissions which do not conform to these rules
5759 may be rejected, even when they contain important and valuable stuff.
5761 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5763 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5764 see http://lists.denx.de/mailman/listinfo/u-boot
5766 When you send a patch, please include the following information with
5769 * For bug fixes: a description of the bug and how your patch fixes
5770 this bug. Please try to include a way of demonstrating that the
5771 patch actually fixes something.
5773 * For new features: a description of the feature and your
5776 * A CHANGELOG entry as plaintext (separate from the patch)
5778 * For major contributions, add a MAINTAINERS file with your
5779 information and associated file and directory references.
5781 * When you add support for a new board, don't forget to add a
5782 maintainer e-mail address to the boards.cfg file, too.
5784 * If your patch adds new configuration options, don't forget to
5785 document these in the README file.
5787 * The patch itself. If you are using git (which is *strongly*
5788 recommended) you can easily generate the patch using the
5789 "git format-patch". If you then use "git send-email" to send it to
5790 the U-Boot mailing list, you will avoid most of the common problems
5791 with some other mail clients.
5793 If you cannot use git, use "diff -purN OLD NEW". If your version of
5794 diff does not support these options, then get the latest version of
5797 The current directory when running this command shall be the parent
5798 directory of the U-Boot source tree (i. e. please make sure that
5799 your patch includes sufficient directory information for the
5802 We prefer patches as plain text. MIME attachments are discouraged,
5803 and compressed attachments must not be used.
5805 * If one logical set of modifications affects or creates several
5806 files, all these changes shall be submitted in a SINGLE patch file.
5808 * Changesets that contain different, unrelated modifications shall be
5809 submitted as SEPARATE patches, one patch per changeset.
5814 * Before sending the patch, run the buildman script on your patched
5815 source tree and make sure that no errors or warnings are reported
5816 for any of the boards.
5818 * Keep your modifications to the necessary minimum: A patch
5819 containing several unrelated changes or arbitrary reformats will be
5820 returned with a request to re-formatting / split it.
5822 * If you modify existing code, make sure that your new code does not
5823 add to the memory footprint of the code ;-) Small is beautiful!
5824 When adding new features, these should compile conditionally only
5825 (using #ifdef), and the resulting code with the new feature
5826 disabled must not need more memory than the old code without your
5829 * Remember that there is a size limit of 100 kB per message on the
5830 u-boot mailing list. Bigger patches will be moderated. If they are
5831 reasonable and not too big, they will be acknowledged. But patches
5832 bigger than the size limit should be avoided.