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_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
409 Defines the endianess of the CPU. Implementation of those
410 values is arch specific.
413 Freescale DDR driver in use. This type of DDR controller is
414 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
417 CONFIG_SYS_FSL_DDR_ADDR
418 Freescale DDR memory-mapped register base.
420 CONFIG_SYS_FSL_DDR_EMU
421 Specify emulator support for DDR. Some DDR features such as
422 deskew training are not available.
424 CONFIG_SYS_FSL_DDRC_GEN1
425 Freescale DDR1 controller.
427 CONFIG_SYS_FSL_DDRC_GEN2
428 Freescale DDR2 controller.
430 CONFIG_SYS_FSL_DDRC_GEN3
431 Freescale DDR3 controller.
433 CONFIG_SYS_FSL_DDRC_GEN4
434 Freescale DDR4 controller.
436 CONFIG_SYS_FSL_DDRC_ARM_GEN3
437 Freescale DDR3 controller for ARM-based SoCs.
440 Board config to use DDR1. It can be enabled for SoCs with
441 Freescale DDR1 or DDR2 controllers, depending on the board
445 Board config to use DDR2. It can be enabled for SoCs with
446 Freescale DDR2 or DDR3 controllers, depending on the board
450 Board config to use DDR3. It can be enabled for SoCs with
451 Freescale DDR3 or DDR3L controllers.
454 Board config to use DDR3L. It can be enabled for SoCs with
458 Board config to use DDR4. It can be enabled for SoCs with
461 CONFIG_SYS_FSL_IFC_BE
462 Defines the IFC controller register space as Big Endian
464 CONFIG_SYS_FSL_IFC_LE
465 Defines the IFC controller register space as Little Endian
467 CONFIG_SYS_FSL_IFC_CLK_DIV
468 Defines divider of platform clock(clock input to IFC controller).
470 CONFIG_SYS_FSL_LBC_CLK_DIV
471 Defines divider of platform clock(clock input to eLBC controller).
473 CONFIG_SYS_FSL_PBL_PBI
474 It enables addition of RCW (Power on reset configuration) in built image.
475 Please refer doc/README.pblimage for more details
477 CONFIG_SYS_FSL_PBL_RCW
478 It adds PBI(pre-boot instructions) commands in u-boot build image.
479 PBI commands can be used to configure SoC before it starts the execution.
480 Please refer doc/README.pblimage for more details
483 It adds a target to create boot binary having SPL binary in PBI format
484 concatenated with u-boot binary.
486 CONFIG_SYS_FSL_DDR_BE
487 Defines the DDR controller register space as Big Endian
489 CONFIG_SYS_FSL_DDR_LE
490 Defines the DDR controller register space as Little Endian
492 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
493 Physical address from the view of DDR controllers. It is the
494 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
495 it could be different for ARM SoCs.
497 CONFIG_SYS_FSL_DDR_INTLV_256B
498 DDR controller interleaving on 256-byte. This is a special
499 interleaving mode, handled by Dickens for Freescale layerscape
502 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
503 Number of controllers used as main memory.
505 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
506 Number of controllers used for other than main memory.
508 CONFIG_SYS_FSL_HAS_DP_DDR
509 Defines the SoC has DP-DDR used for DPAA.
511 CONFIG_SYS_FSL_SEC_BE
512 Defines the SEC controller register space as Big Endian
514 CONFIG_SYS_FSL_SEC_LE
515 Defines the SEC controller register space as Little Endian
518 CONFIG_SYS_INIT_SP_OFFSET
520 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
521 pointer. This is needed for the temporary stack before
524 CONFIG_SYS_MIPS_CACHE_MODE
526 Cache operation mode for the MIPS CPU.
527 See also arch/mips/include/asm/mipsregs.h.
529 CONF_CM_CACHABLE_NO_WA
532 CONF_CM_CACHABLE_NONCOHERENT
536 CONF_CM_CACHABLE_ACCELERATED
538 CONFIG_SYS_XWAY_EBU_BOOTCFG
540 Special option for Lantiq XWAY SoCs for booting from NOR flash.
541 See also arch/mips/cpu/mips32/start.S.
543 CONFIG_XWAY_SWAP_BYTES
545 Enable compilation of tools/xway-swap-bytes needed for Lantiq
546 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
547 be swapped if a flash programmer is used.
550 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
552 Select high exception vectors of the ARM core, e.g., do not
553 clear the V bit of the c1 register of CP15.
556 Generic timer clock source frequency.
558 COUNTER_FREQUENCY_REAL
559 Generic timer clock source frequency if the real clock is
560 different from COUNTER_FREQUENCY, and can only be determined
564 CONFIG_TEGRA_SUPPORT_NON_SECURE
566 Support executing U-Boot in non-secure (NS) mode. Certain
567 impossible actions will be skipped if the CPU is in NS mode,
568 such as ARM architectural timer initialization.
570 - Linux Kernel Interface:
573 U-Boot stores all clock information in Hz
574 internally. For binary compatibility with older Linux
575 kernels (which expect the clocks passed in the
576 bd_info data to be in MHz) the environment variable
577 "clocks_in_mhz" can be defined so that U-Boot
578 converts clock data to MHZ before passing it to the
580 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
581 "clocks_in_mhz=1" is automatically included in the
584 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
586 When transferring memsize parameter to Linux, some versions
587 expect it to be in bytes, others in MB.
588 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
592 New kernel versions are expecting firmware settings to be
593 passed using flattened device trees (based on open firmware
597 * New libfdt-based support
598 * Adds the "fdt" command
599 * The bootm command automatically updates the fdt
601 OF_TBCLK - The timebase frequency.
602 OF_STDOUT_PATH - The path to the console device
604 boards with QUICC Engines require OF_QE to set UCC MAC
607 CONFIG_OF_BOARD_SETUP
609 Board code has addition modification that it wants to make
610 to the flat device tree before handing it off to the kernel
612 CONFIG_OF_SYSTEM_SETUP
614 Other code has addition modification that it wants to make
615 to the flat device tree before handing it off to the kernel.
616 This causes ft_system_setup() to be called before booting
621 U-Boot can detect if an IDE device is present or not.
622 If not, and this new config option is activated, U-Boot
623 removes the ATA node from the DTS before booting Linux,
624 so the Linux IDE driver does not probe the device and
625 crash. This is needed for buggy hardware (uc101) where
626 no pull down resistor is connected to the signal IDE5V_DD7.
628 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
630 This setting is mandatory for all boards that have only one
631 machine type and must be used to specify the machine type
632 number as it appears in the ARM machine registry
633 (see http://www.arm.linux.org.uk/developer/machines/).
634 Only boards that have multiple machine types supported
635 in a single configuration file and the machine type is
636 runtime discoverable, do not have to use this setting.
638 - vxWorks boot parameters:
640 bootvx constructs a valid bootline using the following
641 environments variables: bootdev, bootfile, ipaddr, netmask,
642 serverip, gatewayip, hostname, othbootargs.
643 It loads the vxWorks image pointed bootfile.
645 Note: If a "bootargs" environment is defined, it will overwride
646 the defaults discussed just above.
648 - Cache Configuration:
649 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
650 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
651 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
653 - Cache Configuration for ARM:
654 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
656 CONFIG_SYS_PL310_BASE - Physical base address of PL310
657 controller register space
662 Define this if you want support for Amba PrimeCell PL010 UARTs.
666 Define this if you want support for Amba PrimeCell PL011 UARTs.
670 If you have Amba PrimeCell PL011 UARTs, set this variable to
671 the clock speed of the UARTs.
675 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
676 define this to a list of base addresses for each (supported)
677 port. See e.g. include/configs/versatile.h
679 CONFIG_SERIAL_HW_FLOW_CONTROL
681 Define this variable to enable hw flow control in serial driver.
682 Current user of this option is drivers/serial/nsl16550.c driver
685 CONFIG_BAUDRATE - in bps
686 Select one of the baudrates listed in
687 CONFIG_SYS_BAUDRATE_TABLE, see below.
691 Only needed when CONFIG_BOOTDELAY is enabled;
692 define a command string that is automatically executed
693 when no character is read on the console interface
694 within "Boot Delay" after reset.
696 CONFIG_RAMBOOT and CONFIG_NFSBOOT
697 The value of these goes into the environment as
698 "ramboot" and "nfsboot" respectively, and can be used
699 as a convenience, when switching between booting from
703 CONFIG_BOOTCOUNT_LIMIT
704 Implements a mechanism for detecting a repeating reboot
706 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
709 If no softreset save registers are found on the hardware
710 "bootcount" is stored in the environment. To prevent a
711 saveenv on all reboots, the environment variable
712 "upgrade_available" is used. If "upgrade_available" is
713 0, "bootcount" is always 0, if "upgrade_available" is
714 1 "bootcount" is incremented in the environment.
715 So the Userspace Applikation must set the "upgrade_available"
716 and "bootcount" variable to 0, if a boot was successfully.
721 When this option is #defined, the existence of the
722 environment variable "preboot" will be checked
723 immediately before starting the CONFIG_BOOTDELAY
724 countdown and/or running the auto-boot command resp.
725 entering interactive mode.
727 This feature is especially useful when "preboot" is
728 automatically generated or modified. For an example
729 see the LWMON board specific code: here "preboot" is
730 modified when the user holds down a certain
731 combination of keys on the (special) keyboard when
734 - Serial Download Echo Mode:
736 If defined to 1, all characters received during a
737 serial download (using the "loads" command) are
738 echoed back. This might be needed by some terminal
739 emulations (like "cu"), but may as well just take
740 time on others. This setting #define's the initial
741 value of the "loads_echo" environment variable.
743 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
745 Select one of the baudrates listed in
746 CONFIG_SYS_BAUDRATE_TABLE, see below.
748 - Removal of commands
749 If no commands are needed to boot, you can disable
750 CONFIG_CMDLINE to remove them. In this case, the command line
751 will not be available, and when U-Boot wants to execute the
752 boot command (on start-up) it will call board_run_command()
753 instead. This can reduce image size significantly for very
754 simple boot procedures.
756 - Regular expression support:
758 If this variable is defined, U-Boot is linked against
759 the SLRE (Super Light Regular Expression) library,
760 which adds regex support to some commands, as for
761 example "env grep" and "setexpr".
765 If this variable is defined, U-Boot will use a device tree
766 to configure its devices, instead of relying on statically
767 compiled #defines in the board file. This option is
768 experimental and only available on a few boards. The device
769 tree is available in the global data as gd->fdt_blob.
771 U-Boot needs to get its device tree from somewhere. This can
772 be done using one of the three options below:
775 If this variable is defined, U-Boot will embed a device tree
776 binary in its image. This device tree file should be in the
777 board directory and called <soc>-<board>.dts. The binary file
778 is then picked up in board_init_f() and made available through
779 the global data structure as gd->blob.
782 If this variable is defined, U-Boot will build a device tree
783 binary. It will be called u-boot.dtb. Architecture-specific
784 code will locate it at run-time. Generally this works by:
786 cat u-boot.bin u-boot.dtb >image.bin
788 and in fact, U-Boot does this for you, creating a file called
789 u-boot-dtb.bin which is useful in the common case. You can
790 still use the individual files if you need something more
794 If this variable is defined, U-Boot will use the device tree
795 provided by the board at runtime instead of embedding one with
796 the image. Only boards defining board_fdt_blob_setup() support
797 this option (see include/fdtdec.h file).
801 If this variable is defined, it enables watchdog
802 support for the SoC. There must be support in the SoC
803 specific code for a watchdog. For the 8xx
804 CPUs, the SIU Watchdog feature is enabled in the SYPCR
805 register. When supported for a specific SoC is
806 available, then no further board specific code should
810 When using a watchdog circuitry external to the used
811 SoC, then define this variable and provide board
812 specific code for the "hw_watchdog_reset" function.
814 CONFIG_AT91_HW_WDT_TIMEOUT
815 specify the timeout in seconds. default 2 seconds.
818 CONFIG_VERSION_VARIABLE
819 If this variable is defined, an environment variable
820 named "ver" is created by U-Boot showing the U-Boot
821 version as printed by the "version" command.
822 Any change to this variable will be reverted at the
827 When CONFIG_CMD_DATE is selected, the type of the RTC
828 has to be selected, too. Define exactly one of the
831 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
832 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
833 CONFIG_RTC_MC146818 - use MC146818 RTC
834 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
835 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
836 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
837 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
838 CONFIG_RTC_DS164x - use Dallas DS164x RTC
839 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
840 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
841 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
842 CONFIG_SYS_RV3029_TCR - enable trickle charger on
845 Note that if the RTC uses I2C, then the I2C interface
846 must also be configured. See I2C Support, below.
849 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
851 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
852 chip-ngpio pairs that tell the PCA953X driver the number of
853 pins supported by a particular chip.
855 Note that if the GPIO device uses I2C, then the I2C interface
856 must also be configured. See I2C Support, below.
859 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
860 accesses and can checksum them or write a list of them out
861 to memory. See the 'iotrace' command for details. This is
862 useful for testing device drivers since it can confirm that
863 the driver behaves the same way before and after a code
864 change. Currently this is supported on sandbox and arm. To
865 add support for your architecture, add '#include <iotrace.h>'
866 to the bottom of arch/<arch>/include/asm/io.h and test.
868 Example output from the 'iotrace stats' command is below.
869 Note that if the trace buffer is exhausted, the checksum will
870 still continue to operate.
873 Start: 10000000 (buffer start address)
874 Size: 00010000 (buffer size)
875 Offset: 00000120 (current buffer offset)
876 Output: 10000120 (start + offset)
877 Count: 00000018 (number of trace records)
878 CRC32: 9526fb66 (CRC32 of all trace records)
882 When CONFIG_TIMESTAMP is selected, the timestamp
883 (date and time) of an image is printed by image
884 commands like bootm or iminfo. This option is
885 automatically enabled when you select CONFIG_CMD_DATE .
887 - Partition Labels (disklabels) Supported:
888 Zero or more of the following:
889 CONFIG_MAC_PARTITION Apple's MacOS partition table.
890 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
891 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
892 bootloader. Note 2TB partition limit; see
894 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
896 If IDE or SCSI support is enabled (CONFIG_IDE or
897 CONFIG_SCSI) you must configure support for at
898 least one non-MTD partition type as well.
901 CONFIG_IDE_RESET_ROUTINE - this is defined in several
902 board configurations files but used nowhere!
904 CONFIG_IDE_RESET - is this is defined, IDE Reset will
905 be performed by calling the function
906 ide_set_reset(int reset)
907 which has to be defined in a board specific file
912 Set this to enable ATAPI support.
917 Set this to enable support for disks larger than 137GB
918 Also look at CONFIG_SYS_64BIT_LBA.
919 Whithout these , LBA48 support uses 32bit variables and will 'only'
920 support disks up to 2.1TB.
922 CONFIG_SYS_64BIT_LBA:
923 When enabled, makes the IDE subsystem use 64bit sector addresses.
927 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
928 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
929 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
930 maximum numbers of LUNs, SCSI ID's and target
933 The environment variable 'scsidevs' is set to the number of
934 SCSI devices found during the last scan.
936 - NETWORK Support (PCI):
938 Support for Intel 8254x/8257x gigabit chips.
941 Utility code for direct access to the SPI bus on Intel 8257x.
942 This does not do anything useful unless you set at least one
943 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
945 CONFIG_E1000_SPI_GENERIC
946 Allow generic access to the SPI bus on the Intel 8257x, for
947 example with the "sspi" command.
950 Support for Intel 82557/82559/82559ER chips.
951 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
952 write routine for first time initialisation.
955 Support for Digital 2114x chips.
956 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
957 modem chip initialisation (KS8761/QS6611).
960 Support for National dp83815 chips.
963 Support for National dp8382[01] gigabit chips.
965 - NETWORK Support (other):
967 CONFIG_DRIVER_AT91EMAC
968 Support for AT91RM9200 EMAC.
971 Define this to use reduced MII inteface
973 CONFIG_DRIVER_AT91EMAC_QUIET
974 If this defined, the driver is quiet.
975 The driver doen't show link status messages.
978 Support for the Calxeda XGMAC device
981 Support for SMSC's LAN91C96 chips.
983 CONFIG_LAN91C96_USE_32_BIT
984 Define this to enable 32 bit addressing
987 Support for SMSC's LAN91C111 chip
990 Define this to hold the physical address
991 of the device (I/O space)
993 CONFIG_SMC_USE_32_BIT
994 Define this if data bus is 32 bits
996 CONFIG_SMC_USE_IOFUNCS
997 Define this to use i/o functions instead of macros
998 (some hardware wont work with macros)
1000 CONFIG_DRIVER_TI_EMAC
1001 Support for davinci emac
1003 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1004 Define this if you have more then 3 PHYs.
1007 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1009 CONFIG_FTGMAC100_EGIGA
1010 Define this to use GE link update with gigabit PHY.
1011 Define this if FTGMAC100 is connected to gigabit PHY.
1012 If your system has 10/100 PHY only, it might not occur
1013 wrong behavior. Because PHY usually return timeout or
1014 useless data when polling gigabit status and gigabit
1015 control registers. This behavior won't affect the
1016 correctnessof 10/100 link speed update.
1019 Support for SMSC's LAN911x and LAN921x chips
1022 Define this to hold the physical address
1023 of the device (I/O space)
1025 CONFIG_SMC911X_32_BIT
1026 Define this if data bus is 32 bits
1028 CONFIG_SMC911X_16_BIT
1029 Define this if data bus is 16 bits. If your processor
1030 automatically converts one 32 bit word to two 16 bit
1031 words you may also try CONFIG_SMC911X_32_BIT.
1034 Support for Renesas on-chip Ethernet controller
1036 CONFIG_SH_ETHER_USE_PORT
1037 Define the number of ports to be used
1039 CONFIG_SH_ETHER_PHY_ADDR
1040 Define the ETH PHY's address
1042 CONFIG_SH_ETHER_CACHE_WRITEBACK
1043 If this option is set, the driver enables cache flush.
1047 Support for PWM module on the imx6.
1051 Support TPM devices.
1053 CONFIG_TPM_TIS_INFINEON
1054 Support for Infineon i2c bus TPM devices. Only one device
1055 per system is supported at this time.
1057 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1058 Define the burst count bytes upper limit
1061 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1063 CONFIG_TPM_ST33ZP24_I2C
1064 Support for STMicroelectronics ST33ZP24 I2C devices.
1065 Requires TPM_ST33ZP24 and I2C.
1067 CONFIG_TPM_ST33ZP24_SPI
1068 Support for STMicroelectronics ST33ZP24 SPI devices.
1069 Requires TPM_ST33ZP24 and SPI.
1071 CONFIG_TPM_ATMEL_TWI
1072 Support for Atmel TWI TPM device. Requires I2C support.
1075 Support for generic parallel port TPM devices. Only one device
1076 per system is supported at this time.
1078 CONFIG_TPM_TIS_BASE_ADDRESS
1079 Base address where the generic TPM device is mapped
1080 to. Contemporary x86 systems usually map it at
1084 Define this to enable the TPM support library which provides
1085 functional interfaces to some TPM commands.
1086 Requires support for a TPM device.
1088 CONFIG_TPM_AUTH_SESSIONS
1089 Define this to enable authorized functions in the TPM library.
1090 Requires CONFIG_TPM and CONFIG_SHA1.
1093 At the moment only the UHCI host controller is
1094 supported (PIP405, MIP405); define
1095 CONFIG_USB_UHCI to enable it.
1096 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1097 and define CONFIG_USB_STORAGE to enable the USB
1100 Supported are USB Keyboards and USB Floppy drives
1103 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1104 txfilltuning field in the EHCI controller on reset.
1106 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1107 HW module registers.
1110 Define the below if you wish to use the USB console.
1111 Once firmware is rebuilt from a serial console issue the
1112 command "setenv stdin usbtty; setenv stdout usbtty" and
1113 attach your USB cable. The Unix command "dmesg" should print
1114 it has found a new device. The environment variable usbtty
1115 can be set to gserial or cdc_acm to enable your device to
1116 appear to a USB host as a Linux gserial device or a
1117 Common Device Class Abstract Control Model serial device.
1118 If you select usbtty = gserial you should be able to enumerate
1120 # modprobe usbserial vendor=0xVendorID product=0xProductID
1121 else if using cdc_acm, simply setting the environment
1122 variable usbtty to be cdc_acm should suffice. The following
1123 might be defined in YourBoardName.h
1126 Define this to build a UDC device
1129 Define this to have a tty type of device available to
1130 talk to the UDC device
1133 Define this to enable the high speed support for usb
1134 device and usbtty. If this feature is enabled, a routine
1135 int is_usbd_high_speed(void)
1136 also needs to be defined by the driver to dynamically poll
1137 whether the enumeration has succeded at high speed or full
1140 CONFIG_SYS_CONSOLE_IS_IN_ENV
1141 Define this if you want stdin, stdout &/or stderr to
1144 If you have a USB-IF assigned VendorID then you may wish to
1145 define your own vendor specific values either in BoardName.h
1146 or directly in usbd_vendor_info.h. If you don't define
1147 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1148 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1149 should pretend to be a Linux device to it's target host.
1151 CONFIG_USBD_MANUFACTURER
1152 Define this string as the name of your company for
1153 - CONFIG_USBD_MANUFACTURER "my company"
1155 CONFIG_USBD_PRODUCT_NAME
1156 Define this string as the name of your product
1157 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1159 CONFIG_USBD_VENDORID
1160 Define this as your assigned Vendor ID from the USB
1161 Implementors Forum. This *must* be a genuine Vendor ID
1162 to avoid polluting the USB namespace.
1163 - CONFIG_USBD_VENDORID 0xFFFF
1165 CONFIG_USBD_PRODUCTID
1166 Define this as the unique Product ID
1168 - CONFIG_USBD_PRODUCTID 0xFFFF
1170 - ULPI Layer Support:
1171 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1172 the generic ULPI layer. The generic layer accesses the ULPI PHY
1173 via the platform viewport, so you need both the genric layer and
1174 the viewport enabled. Currently only Chipidea/ARC based
1175 viewport is supported.
1176 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1177 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1178 If your ULPI phy needs a different reference clock than the
1179 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1180 the appropriate value in Hz.
1183 The MMC controller on the Intel PXA is supported. To
1184 enable this define CONFIG_MMC. The MMC can be
1185 accessed from the boot prompt by mapping the device
1186 to physical memory similar to flash. Command line is
1187 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1188 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1191 Support for Renesas on-chip MMCIF controller
1193 CONFIG_SH_MMCIF_ADDR
1194 Define the base address of MMCIF registers
1197 Define the clock frequency for MMCIF
1199 CONFIG_SUPPORT_EMMC_BOOT
1200 Enable some additional features of the eMMC boot partitions.
1202 CONFIG_SUPPORT_EMMC_RPMB
1203 Enable the commands for reading, writing and programming the
1204 key for the Replay Protection Memory Block partition in eMMC.
1206 - USB Device Firmware Update (DFU) class support:
1207 CONFIG_USB_FUNCTION_DFU
1208 This enables the USB portion of the DFU USB class
1211 This enables support for exposing (e)MMC devices via DFU.
1214 This enables support for exposing NAND devices via DFU.
1217 This enables support for exposing RAM via DFU.
1218 Note: DFU spec refer to non-volatile memory usage, but
1219 allow usages beyond the scope of spec - here RAM usage,
1220 one that would help mostly the developer.
1222 CONFIG_SYS_DFU_DATA_BUF_SIZE
1223 Dfu transfer uses a buffer before writing data to the
1224 raw storage device. Make the size (in bytes) of this buffer
1225 configurable. The size of this buffer is also configurable
1226 through the "dfu_bufsiz" environment variable.
1228 CONFIG_SYS_DFU_MAX_FILE_SIZE
1229 When updating files rather than the raw storage device,
1230 we use a static buffer to copy the file into and then write
1231 the buffer once we've been given the whole file. Define
1232 this to the maximum filesize (in bytes) for the buffer.
1233 Default is 4 MiB if undefined.
1235 DFU_DEFAULT_POLL_TIMEOUT
1236 Poll timeout [ms], is the timeout a device can send to the
1237 host. The host must wait for this timeout before sending
1238 a subsequent DFU_GET_STATUS request to the device.
1240 DFU_MANIFEST_POLL_TIMEOUT
1241 Poll timeout [ms], which the device sends to the host when
1242 entering dfuMANIFEST state. Host waits this timeout, before
1243 sending again an USB request to the device.
1245 - Journaling Flash filesystem support:
1247 Define these for a default partition on a NAND device
1249 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1250 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1251 Define these for a default partition on a NOR device
1254 See Kconfig help for available keyboard drivers.
1258 Define this to enable a custom keyboard support.
1259 This simply calls drv_keyboard_init() which must be
1260 defined in your board-specific files. This option is deprecated
1261 and is only used by novena. For new boards, use driver model
1266 Enable the Freescale DIU video driver. Reference boards for
1267 SOCs that have a DIU should define this macro to enable DIU
1268 support, and should also define these other macros:
1273 CONFIG_VIDEO_SW_CURSOR
1274 CONFIG_VGA_AS_SINGLE_DEVICE
1276 CONFIG_VIDEO_BMP_LOGO
1278 The DIU driver will look for the 'video-mode' environment
1279 variable, and if defined, enable the DIU as a console during
1280 boot. See the documentation file doc/README.video for a
1281 description of this variable.
1283 - LCD Support: CONFIG_LCD
1285 Define this to enable LCD support (for output to LCD
1286 display); also select one of the supported displays
1287 by defining one of these:
1291 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1293 CONFIG_NEC_NL6448AC33:
1295 NEC NL6448AC33-18. Active, color, single scan.
1297 CONFIG_NEC_NL6448BC20
1299 NEC NL6448BC20-08. 6.5", 640x480.
1300 Active, color, single scan.
1302 CONFIG_NEC_NL6448BC33_54
1304 NEC NL6448BC33-54. 10.4", 640x480.
1305 Active, color, single scan.
1309 Sharp 320x240. Active, color, single scan.
1310 It isn't 16x9, and I am not sure what it is.
1312 CONFIG_SHARP_LQ64D341
1314 Sharp LQ64D341 display, 640x480.
1315 Active, color, single scan.
1319 HLD1045 display, 640x480.
1320 Active, color, single scan.
1324 Optrex CBL50840-2 NF-FW 99 22 M5
1326 Hitachi LMG6912RPFC-00T
1330 320x240. Black & white.
1332 CONFIG_LCD_ALIGNMENT
1334 Normally the LCD is page-aligned (typically 4KB). If this is
1335 defined then the LCD will be aligned to this value instead.
1336 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1337 here, since it is cheaper to change data cache settings on
1338 a per-section basis.
1343 Sometimes, for example if the display is mounted in portrait
1344 mode or even if it's mounted landscape but rotated by 180degree,
1345 we need to rotate our content of the display relative to the
1346 framebuffer, so that user can read the messages which are
1348 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1349 initialized with a given rotation from "vl_rot" out of
1350 "vidinfo_t" which is provided by the board specific code.
1351 The value for vl_rot is coded as following (matching to
1352 fbcon=rotate:<n> linux-kernel commandline):
1353 0 = no rotation respectively 0 degree
1354 1 = 90 degree rotation
1355 2 = 180 degree rotation
1356 3 = 270 degree rotation
1358 If CONFIG_LCD_ROTATION is not defined, the console will be
1359 initialized with 0degree rotation.
1363 Support drawing of RLE8-compressed bitmaps on the LCD.
1367 Enables an 'i2c edid' command which can read EDID
1368 information over I2C from an attached LCD display.
1370 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1372 If this option is set, the environment is checked for
1373 a variable "splashimage". If found, the usual display
1374 of logo, copyright and system information on the LCD
1375 is suppressed and the BMP image at the address
1376 specified in "splashimage" is loaded instead. The
1377 console is redirected to the "nulldev", too. This
1378 allows for a "silent" boot where a splash screen is
1379 loaded very quickly after power-on.
1381 CONFIG_SPLASHIMAGE_GUARD
1383 If this option is set, then U-Boot will prevent the environment
1384 variable "splashimage" from being set to a problematic address
1385 (see doc/README.displaying-bmps).
1386 This option is useful for targets where, due to alignment
1387 restrictions, an improperly aligned BMP image will cause a data
1388 abort. If you think you will not have problems with unaligned
1389 accesses (for example because your toolchain prevents them)
1390 there is no need to set this option.
1392 CONFIG_SPLASH_SCREEN_ALIGN
1394 If this option is set the splash image can be freely positioned
1395 on the screen. Environment variable "splashpos" specifies the
1396 position as "x,y". If a positive number is given it is used as
1397 number of pixel from left/top. If a negative number is given it
1398 is used as number of pixel from right/bottom. You can also
1399 specify 'm' for centering the image.
1402 setenv splashpos m,m
1403 => image at center of screen
1405 setenv splashpos 30,20
1406 => image at x = 30 and y = 20
1408 setenv splashpos -10,m
1409 => vertically centered image
1410 at x = dspWidth - bmpWidth - 9
1412 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1414 If this option is set, additionally to standard BMP
1415 images, gzipped BMP images can be displayed via the
1416 splashscreen support or the bmp command.
1418 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1420 If this option is set, 8-bit RLE compressed BMP images
1421 can be displayed via the splashscreen support or the
1424 - Compression support:
1427 Enabled by default to support gzip compressed images.
1431 If this option is set, support for bzip2 compressed
1432 images is included. If not, only uncompressed and gzip
1433 compressed images are supported.
1435 NOTE: the bzip2 algorithm requires a lot of RAM, so
1436 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1442 The address of PHY on MII bus.
1444 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1446 The clock frequency of the MII bus
1448 CONFIG_PHY_RESET_DELAY
1450 Some PHY like Intel LXT971A need extra delay after
1451 reset before any MII register access is possible.
1452 For such PHY, set this option to the usec delay
1453 required. (minimum 300usec for LXT971A)
1455 CONFIG_PHY_CMD_DELAY (ppc4xx)
1457 Some PHY like Intel LXT971A need extra delay after
1458 command issued before MII status register can be read
1463 Define a default value for the IP address to use for
1464 the default Ethernet interface, in case this is not
1465 determined through e.g. bootp.
1466 (Environment variable "ipaddr")
1468 - Server IP address:
1471 Defines a default value for the IP address of a TFTP
1472 server to contact when using the "tftboot" command.
1473 (Environment variable "serverip")
1475 CONFIG_KEEP_SERVERADDR
1477 Keeps the server's MAC address, in the env 'serveraddr'
1478 for passing to bootargs (like Linux's netconsole option)
1480 - Gateway IP address:
1483 Defines a default value for the IP address of the
1484 default router where packets to other networks are
1486 (Environment variable "gatewayip")
1491 Defines a default value for the subnet mask (or
1492 routing prefix) which is used to determine if an IP
1493 address belongs to the local subnet or needs to be
1494 forwarded through a router.
1495 (Environment variable "netmask")
1497 - Multicast TFTP Mode:
1500 Defines whether you want to support multicast TFTP as per
1501 rfc-2090; for example to work with atftp. Lets lots of targets
1502 tftp down the same boot image concurrently. Note: the Ethernet
1503 driver in use must provide a function: mcast() to join/leave a
1506 - BOOTP Recovery Mode:
1507 CONFIG_BOOTP_RANDOM_DELAY
1509 If you have many targets in a network that try to
1510 boot using BOOTP, you may want to avoid that all
1511 systems send out BOOTP requests at precisely the same
1512 moment (which would happen for instance at recovery
1513 from a power failure, when all systems will try to
1514 boot, thus flooding the BOOTP server. Defining
1515 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1516 inserted before sending out BOOTP requests. The
1517 following delays are inserted then:
1519 1st BOOTP request: delay 0 ... 1 sec
1520 2nd BOOTP request: delay 0 ... 2 sec
1521 3rd BOOTP request: delay 0 ... 4 sec
1523 BOOTP requests: delay 0 ... 8 sec
1525 CONFIG_BOOTP_ID_CACHE_SIZE
1527 BOOTP packets are uniquely identified using a 32-bit ID. The
1528 server will copy the ID from client requests to responses and
1529 U-Boot will use this to determine if it is the destination of
1530 an incoming response. Some servers will check that addresses
1531 aren't in use before handing them out (usually using an ARP
1532 ping) and therefore take up to a few hundred milliseconds to
1533 respond. Network congestion may also influence the time it
1534 takes for a response to make it back to the client. If that
1535 time is too long, U-Boot will retransmit requests. In order
1536 to allow earlier responses to still be accepted after these
1537 retransmissions, U-Boot's BOOTP client keeps a small cache of
1538 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1539 cache. The default is to keep IDs for up to four outstanding
1540 requests. Increasing this will allow U-Boot to accept offers
1541 from a BOOTP client in networks with unusually high latency.
1543 - DHCP Advanced Options:
1544 You can fine tune the DHCP functionality by defining
1545 CONFIG_BOOTP_* symbols:
1547 CONFIG_BOOTP_SUBNETMASK
1548 CONFIG_BOOTP_GATEWAY
1549 CONFIG_BOOTP_HOSTNAME
1550 CONFIG_BOOTP_NISDOMAIN
1551 CONFIG_BOOTP_BOOTPATH
1552 CONFIG_BOOTP_BOOTFILESIZE
1555 CONFIG_BOOTP_SEND_HOSTNAME
1556 CONFIG_BOOTP_NTPSERVER
1557 CONFIG_BOOTP_TIMEOFFSET
1558 CONFIG_BOOTP_VENDOREX
1559 CONFIG_BOOTP_MAY_FAIL
1561 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1562 environment variable, not the BOOTP server.
1564 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1565 after the configured retry count, the call will fail
1566 instead of starting over. This can be used to fail over
1567 to Link-local IP address configuration if the DHCP server
1570 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1571 serverip from a DHCP server, it is possible that more
1572 than one DNS serverip is offered to the client.
1573 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1574 serverip will be stored in the additional environment
1575 variable "dnsip2". The first DNS serverip is always
1576 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1579 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1580 to do a dynamic update of a DNS server. To do this, they
1581 need the hostname of the DHCP requester.
1582 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1583 of the "hostname" environment variable is passed as
1584 option 12 to the DHCP server.
1586 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1588 A 32bit value in microseconds for a delay between
1589 receiving a "DHCP Offer" and sending the "DHCP Request".
1590 This fixes a problem with certain DHCP servers that don't
1591 respond 100% of the time to a "DHCP request". E.g. On an
1592 AT91RM9200 processor running at 180MHz, this delay needed
1593 to be *at least* 15,000 usec before a Windows Server 2003
1594 DHCP server would reply 100% of the time. I recommend at
1595 least 50,000 usec to be safe. The alternative is to hope
1596 that one of the retries will be successful but note that
1597 the DHCP timeout and retry process takes a longer than
1600 - Link-local IP address negotiation:
1601 Negotiate with other link-local clients on the local network
1602 for an address that doesn't require explicit configuration.
1603 This is especially useful if a DHCP server cannot be guaranteed
1604 to exist in all environments that the device must operate.
1606 See doc/README.link-local for more information.
1609 CONFIG_CDP_DEVICE_ID
1611 The device id used in CDP trigger frames.
1613 CONFIG_CDP_DEVICE_ID_PREFIX
1615 A two character string which is prefixed to the MAC address
1620 A printf format string which contains the ascii name of
1621 the port. Normally is set to "eth%d" which sets
1622 eth0 for the first Ethernet, eth1 for the second etc.
1624 CONFIG_CDP_CAPABILITIES
1626 A 32bit integer which indicates the device capabilities;
1627 0x00000010 for a normal host which does not forwards.
1631 An ascii string containing the version of the software.
1635 An ascii string containing the name of the platform.
1639 A 32bit integer sent on the trigger.
1641 CONFIG_CDP_POWER_CONSUMPTION
1643 A 16bit integer containing the power consumption of the
1644 device in .1 of milliwatts.
1646 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1648 A byte containing the id of the VLAN.
1650 - Status LED: CONFIG_LED_STATUS
1652 Several configurations allow to display the current
1653 status using a LED. For instance, the LED will blink
1654 fast while running U-Boot code, stop blinking as
1655 soon as a reply to a BOOTP request was received, and
1656 start blinking slow once the Linux kernel is running
1657 (supported by a status LED driver in the Linux
1658 kernel). Defining CONFIG_LED_STATUS enables this
1663 CONFIG_LED_STATUS_GPIO
1664 The status LED can be connected to a GPIO pin.
1665 In such cases, the gpio_led driver can be used as a
1666 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1667 to include the gpio_led driver in the U-Boot binary.
1669 CONFIG_GPIO_LED_INVERTED_TABLE
1670 Some GPIO connected LEDs may have inverted polarity in which
1671 case the GPIO high value corresponds to LED off state and
1672 GPIO low value corresponds to LED on state.
1673 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1674 with a list of GPIO LEDs that have inverted polarity.
1676 - I2C Support: CONFIG_SYS_I2C
1678 This enable the NEW i2c subsystem, and will allow you to use
1679 i2c commands at the u-boot command line (as long as you set
1680 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1681 based realtime clock chips or other i2c devices. See
1682 common/cmd_i2c.c for a description of the command line
1685 ported i2c driver to the new framework:
1686 - drivers/i2c/soft_i2c.c:
1687 - activate first bus with CONFIG_SYS_I2C_SOFT define
1688 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1689 for defining speed and slave address
1690 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1691 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1692 for defining speed and slave address
1693 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1694 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1695 for defining speed and slave address
1696 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1697 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1698 for defining speed and slave address
1700 - drivers/i2c/fsl_i2c.c:
1701 - activate i2c driver with CONFIG_SYS_I2C_FSL
1702 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1703 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1704 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1706 - If your board supports a second fsl i2c bus, define
1707 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1708 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1709 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1712 - drivers/i2c/tegra_i2c.c:
1713 - activate this driver with CONFIG_SYS_I2C_TEGRA
1714 - This driver adds 4 i2c buses with a fix speed from
1715 100000 and the slave addr 0!
1717 - drivers/i2c/ppc4xx_i2c.c
1718 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1719 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1720 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1722 - drivers/i2c/i2c_mxc.c
1723 - activate this driver with CONFIG_SYS_I2C_MXC
1724 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1725 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1726 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1727 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1728 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1729 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1730 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1731 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1732 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1733 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1734 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1735 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1736 If those defines are not set, default value is 100000
1737 for speed, and 0 for slave.
1739 - drivers/i2c/rcar_i2c.c:
1740 - activate this driver with CONFIG_SYS_I2C_RCAR
1741 - This driver adds 4 i2c buses
1743 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1744 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1745 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1746 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1747 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1748 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1749 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1750 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1751 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1753 - drivers/i2c/sh_i2c.c:
1754 - activate this driver with CONFIG_SYS_I2C_SH
1755 - This driver adds from 2 to 5 i2c buses
1757 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1758 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1759 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1760 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1761 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1762 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1763 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1764 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1765 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1766 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1767 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1769 - drivers/i2c/omap24xx_i2c.c
1770 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1771 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1772 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1773 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1774 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1775 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1776 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1777 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1778 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1779 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1780 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1782 - drivers/i2c/zynq_i2c.c
1783 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1784 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1785 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1787 - drivers/i2c/s3c24x0_i2c.c:
1788 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1789 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1790 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1791 with a fix speed from 100000 and the slave addr 0!
1793 - drivers/i2c/ihs_i2c.c
1794 - activate this driver with CONFIG_SYS_I2C_IHS
1795 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1796 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1797 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1798 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1799 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1800 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1801 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1802 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1803 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1804 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1805 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1806 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1807 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1808 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1809 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1810 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1811 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1812 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1813 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1814 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1815 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1819 CONFIG_SYS_NUM_I2C_BUSES
1820 Hold the number of i2c buses you want to use.
1822 CONFIG_SYS_I2C_DIRECT_BUS
1823 define this, if you don't use i2c muxes on your hardware.
1824 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1827 CONFIG_SYS_I2C_MAX_HOPS
1828 define how many muxes are maximal consecutively connected
1829 on one i2c bus. If you not use i2c muxes, omit this
1832 CONFIG_SYS_I2C_BUSES
1833 hold a list of buses you want to use, only used if
1834 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1835 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1836 CONFIG_SYS_NUM_I2C_BUSES = 9:
1838 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1839 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1840 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1841 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1842 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1843 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1844 {1, {I2C_NULL_HOP}}, \
1845 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1846 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1850 bus 0 on adapter 0 without a mux
1851 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1852 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1853 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1854 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1855 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1856 bus 6 on adapter 1 without a mux
1857 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1858 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1860 If you do not have i2c muxes on your board, omit this define.
1862 - Legacy I2C Support:
1863 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1864 then the following macros need to be defined (examples are
1865 from include/configs/lwmon.h):
1869 (Optional). Any commands necessary to enable the I2C
1870 controller or configure ports.
1872 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1876 The code necessary to make the I2C data line active
1877 (driven). If the data line is open collector, this
1880 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1884 The code necessary to make the I2C data line tri-stated
1885 (inactive). If the data line is open collector, this
1888 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1892 Code that returns true if the I2C data line is high,
1895 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1899 If <bit> is true, sets the I2C data line high. If it
1900 is false, it clears it (low).
1902 eg: #define I2C_SDA(bit) \
1903 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1904 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1908 If <bit> is true, sets the I2C clock line high. If it
1909 is false, it clears it (low).
1911 eg: #define I2C_SCL(bit) \
1912 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1913 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1917 This delay is invoked four times per clock cycle so this
1918 controls the rate of data transfer. The data rate thus
1919 is 1 / (I2C_DELAY * 4). Often defined to be something
1922 #define I2C_DELAY udelay(2)
1924 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1926 If your arch supports the generic GPIO framework (asm/gpio.h),
1927 then you may alternatively define the two GPIOs that are to be
1928 used as SCL / SDA. Any of the previous I2C_xxx macros will
1929 have GPIO-based defaults assigned to them as appropriate.
1931 You should define these to the GPIO value as given directly to
1932 the generic GPIO functions.
1934 CONFIG_SYS_I2C_INIT_BOARD
1936 When a board is reset during an i2c bus transfer
1937 chips might think that the current transfer is still
1938 in progress. On some boards it is possible to access
1939 the i2c SCLK line directly, either by using the
1940 processor pin as a GPIO or by having a second pin
1941 connected to the bus. If this option is defined a
1942 custom i2c_init_board() routine in boards/xxx/board.c
1943 is run early in the boot sequence.
1945 CONFIG_I2C_MULTI_BUS
1947 This option allows the use of multiple I2C buses, each of which
1948 must have a controller. At any point in time, only one bus is
1949 active. To switch to a different bus, use the 'i2c dev' command.
1950 Note that bus numbering is zero-based.
1952 CONFIG_SYS_I2C_NOPROBES
1954 This option specifies a list of I2C devices that will be skipped
1955 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1956 is set, specify a list of bus-device pairs. Otherwise, specify
1957 a 1D array of device addresses
1960 #undef CONFIG_I2C_MULTI_BUS
1961 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1963 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1965 #define CONFIG_I2C_MULTI_BUS
1966 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1968 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1970 CONFIG_SYS_SPD_BUS_NUM
1972 If defined, then this indicates the I2C bus number for DDR SPD.
1973 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1975 CONFIG_SYS_RTC_BUS_NUM
1977 If defined, then this indicates the I2C bus number for the RTC.
1978 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1980 CONFIG_SOFT_I2C_READ_REPEATED_START
1982 defining this will force the i2c_read() function in
1983 the soft_i2c driver to perform an I2C repeated start
1984 between writing the address pointer and reading the
1985 data. If this define is omitted the default behaviour
1986 of doing a stop-start sequence will be used. Most I2C
1987 devices can use either method, but some require one or
1990 - SPI Support: CONFIG_SPI
1992 Enables SPI driver (so far only tested with
1993 SPI EEPROM, also an instance works with Crystal A/D and
1994 D/As on the SACSng board)
1998 Enables the driver for SPI controller on SuperH. Currently
1999 only SH7757 is supported.
2003 Enables a software (bit-bang) SPI driver rather than
2004 using hardware support. This is a general purpose
2005 driver that only requires three general I/O port pins
2006 (two outputs, one input) to function. If this is
2007 defined, the board configuration must define several
2008 SPI configuration items (port pins to use, etc). For
2009 an example, see include/configs/sacsng.h.
2013 Enables a hardware SPI driver for general-purpose reads
2014 and writes. As with CONFIG_SOFT_SPI, the board configuration
2015 must define a list of chip-select function pointers.
2016 Currently supported on some MPC8xxx processors. For an
2017 example, see include/configs/mpc8349emds.h.
2021 Enables the driver for the SPI controllers on i.MX and MXC
2022 SoCs. Currently i.MX31/35/51 are supported.
2024 CONFIG_SYS_SPI_MXC_WAIT
2025 Timeout for waiting until spi transfer completed.
2026 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2028 - FPGA Support: CONFIG_FPGA
2030 Enables FPGA subsystem.
2032 CONFIG_FPGA_<vendor>
2034 Enables support for specific chip vendors.
2037 CONFIG_FPGA_<family>
2039 Enables support for FPGA family.
2040 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2044 Specify the number of FPGA devices to support.
2046 CONFIG_SYS_FPGA_PROG_FEEDBACK
2048 Enable printing of hash marks during FPGA configuration.
2050 CONFIG_SYS_FPGA_CHECK_BUSY
2052 Enable checks on FPGA configuration interface busy
2053 status by the configuration function. This option
2054 will require a board or device specific function to
2059 If defined, a function that provides delays in the FPGA
2060 configuration driver.
2062 CONFIG_SYS_FPGA_CHECK_CTRLC
2063 Allow Control-C to interrupt FPGA configuration
2065 CONFIG_SYS_FPGA_CHECK_ERROR
2067 Check for configuration errors during FPGA bitfile
2068 loading. For example, abort during Virtex II
2069 configuration if the INIT_B line goes low (which
2070 indicated a CRC error).
2072 CONFIG_SYS_FPGA_WAIT_INIT
2074 Maximum time to wait for the INIT_B line to de-assert
2075 after PROB_B has been de-asserted during a Virtex II
2076 FPGA configuration sequence. The default time is 500
2079 CONFIG_SYS_FPGA_WAIT_BUSY
2081 Maximum time to wait for BUSY to de-assert during
2082 Virtex II FPGA configuration. The default is 5 ms.
2084 CONFIG_SYS_FPGA_WAIT_CONFIG
2086 Time to wait after FPGA configuration. The default is
2089 - Configuration Management:
2092 Some SoCs need special image types (e.g. U-Boot binary
2093 with a special header) as build targets. By defining
2094 CONFIG_BUILD_TARGET in the SoC / board header, this
2095 special image will be automatically built upon calling
2100 If defined, this string will be added to the U-Boot
2101 version information (U_BOOT_VERSION)
2103 - Vendor Parameter Protection:
2105 U-Boot considers the values of the environment
2106 variables "serial#" (Board Serial Number) and
2107 "ethaddr" (Ethernet Address) to be parameters that
2108 are set once by the board vendor / manufacturer, and
2109 protects these variables from casual modification by
2110 the user. Once set, these variables are read-only,
2111 and write or delete attempts are rejected. You can
2112 change this behaviour:
2114 If CONFIG_ENV_OVERWRITE is #defined in your config
2115 file, the write protection for vendor parameters is
2116 completely disabled. Anybody can change or delete
2119 Alternatively, if you define _both_ an ethaddr in the
2120 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2121 Ethernet address is installed in the environment,
2122 which can be changed exactly ONCE by the user. [The
2123 serial# is unaffected by this, i. e. it remains
2126 The same can be accomplished in a more flexible way
2127 for any variable by configuring the type of access
2128 to allow for those variables in the ".flags" variable
2129 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2134 Define this variable to enable the reservation of
2135 "protected RAM", i. e. RAM which is not overwritten
2136 by U-Boot. Define CONFIG_PRAM to hold the number of
2137 kB you want to reserve for pRAM. You can overwrite
2138 this default value by defining an environment
2139 variable "pram" to the number of kB you want to
2140 reserve. Note that the board info structure will
2141 still show the full amount of RAM. If pRAM is
2142 reserved, a new environment variable "mem" will
2143 automatically be defined to hold the amount of
2144 remaining RAM in a form that can be passed as boot
2145 argument to Linux, for instance like that:
2147 setenv bootargs ... mem=\${mem}
2150 This way you can tell Linux not to use this memory,
2151 either, which results in a memory region that will
2152 not be affected by reboots.
2154 *WARNING* If your board configuration uses automatic
2155 detection of the RAM size, you must make sure that
2156 this memory test is non-destructive. So far, the
2157 following board configurations are known to be
2160 IVMS8, IVML24, SPD8xx,
2161 HERMES, IP860, RPXlite, LWMON,
2164 - Access to physical memory region (> 4GB)
2165 Some basic support is provided for operations on memory not
2166 normally accessible to U-Boot - e.g. some architectures
2167 support access to more than 4GB of memory on 32-bit
2168 machines using physical address extension or similar.
2169 Define CONFIG_PHYSMEM to access this basic support, which
2170 currently only supports clearing the memory.
2175 Define this variable to stop the system in case of a
2176 fatal error, so that you have to reset it manually.
2177 This is probably NOT a good idea for an embedded
2178 system where you want the system to reboot
2179 automatically as fast as possible, but it may be
2180 useful during development since you can try to debug
2181 the conditions that lead to the situation.
2183 CONFIG_NET_RETRY_COUNT
2185 This variable defines the number of retries for
2186 network operations like ARP, RARP, TFTP, or BOOTP
2187 before giving up the operation. If not defined, a
2188 default value of 5 is used.
2192 Timeout waiting for an ARP reply in milliseconds.
2196 Timeout in milliseconds used in NFS protocol.
2197 If you encounter "ERROR: Cannot umount" in nfs command,
2198 try longer timeout such as
2199 #define CONFIG_NFS_TIMEOUT 10000UL
2201 - Command Interpreter:
2202 CONFIG_AUTO_COMPLETE
2204 Enable auto completion of commands using TAB.
2206 CONFIG_SYS_PROMPT_HUSH_PS2
2208 This defines the secondary prompt string, which is
2209 printed when the command interpreter needs more input
2210 to complete a command. Usually "> ".
2214 In the current implementation, the local variables
2215 space and global environment variables space are
2216 separated. Local variables are those you define by
2217 simply typing `name=value'. To access a local
2218 variable later on, you have write `$name' or
2219 `${name}'; to execute the contents of a variable
2220 directly type `$name' at the command prompt.
2222 Global environment variables are those you use
2223 setenv/printenv to work with. To run a command stored
2224 in such a variable, you need to use the run command,
2225 and you must not use the '$' sign to access them.
2227 To store commands and special characters in a
2228 variable, please use double quotation marks
2229 surrounding the whole text of the variable, instead
2230 of the backslashes before semicolons and special
2233 - Command Line Editing and History:
2234 CONFIG_CMDLINE_EDITING
2236 Enable editing and History functions for interactive
2237 command line input operations
2239 - Command Line PS1/PS2 support:
2240 CONFIG_CMDLINE_PS_SUPPORT
2242 Enable support for changing the command prompt string
2243 at run-time. Only static string is supported so far.
2244 The string is obtained from environment variables PS1
2247 - Default Environment:
2248 CONFIG_EXTRA_ENV_SETTINGS
2250 Define this to contain any number of null terminated
2251 strings (variable = value pairs) that will be part of
2252 the default environment compiled into the boot image.
2254 For example, place something like this in your
2255 board's config file:
2257 #define CONFIG_EXTRA_ENV_SETTINGS \
2261 Warning: This method is based on knowledge about the
2262 internal format how the environment is stored by the
2263 U-Boot code. This is NOT an official, exported
2264 interface! Although it is unlikely that this format
2265 will change soon, there is no guarantee either.
2266 You better know what you are doing here.
2268 Note: overly (ab)use of the default environment is
2269 discouraged. Make sure to check other ways to preset
2270 the environment like the "source" command or the
2273 CONFIG_ENV_VARS_UBOOT_CONFIG
2275 Define this in order to add variables describing the
2276 U-Boot build configuration to the default environment.
2277 These will be named arch, cpu, board, vendor, and soc.
2279 Enabling this option will cause the following to be defined:
2287 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2289 Define this in order to add variables describing certain
2290 run-time determined information about the hardware to the
2291 environment. These will be named board_name, board_rev.
2293 CONFIG_DELAY_ENVIRONMENT
2295 Normally the environment is loaded when the board is
2296 initialised so that it is available to U-Boot. This inhibits
2297 that so that the environment is not available until
2298 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2299 this is instead controlled by the value of
2300 /config/load-environment.
2302 - DataFlash Support:
2303 CONFIG_HAS_DATAFLASH
2305 Defining this option enables DataFlash features and
2306 allows to read/write in Dataflash via the standard
2309 - Serial Flash support
2310 Usage requires an initial 'sf probe' to define the serial
2311 flash parameters, followed by read/write/erase/update
2314 The following defaults may be provided by the platform
2315 to handle the common case when only a single serial
2316 flash is present on the system.
2318 CONFIG_SF_DEFAULT_BUS Bus identifier
2319 CONFIG_SF_DEFAULT_CS Chip-select
2320 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2321 CONFIG_SF_DEFAULT_SPEED in Hz
2325 Adding this option adds support for Xilinx SystemACE
2326 chips attached via some sort of local bus. The address
2327 of the chip must also be defined in the
2328 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2330 #define CONFIG_SYSTEMACE
2331 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2333 When SystemACE support is added, the "ace" device type
2334 becomes available to the fat commands, i.e. fatls.
2336 - TFTP Fixed UDP Port:
2339 If this is defined, the environment variable tftpsrcp
2340 is used to supply the TFTP UDP source port value.
2341 If tftpsrcp isn't defined, the normal pseudo-random port
2342 number generator is used.
2344 Also, the environment variable tftpdstp is used to supply
2345 the TFTP UDP destination port value. If tftpdstp isn't
2346 defined, the normal port 69 is used.
2348 The purpose for tftpsrcp is to allow a TFTP server to
2349 blindly start the TFTP transfer using the pre-configured
2350 target IP address and UDP port. This has the effect of
2351 "punching through" the (Windows XP) firewall, allowing
2352 the remainder of the TFTP transfer to proceed normally.
2353 A better solution is to properly configure the firewall,
2354 but sometimes that is not allowed.
2356 - bootcount support:
2357 CONFIG_BOOTCOUNT_LIMIT
2359 This enables the bootcounter support, see:
2360 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2363 enable special bootcounter support on at91sam9xe based boards.
2365 enable special bootcounter support on da850 based boards.
2366 CONFIG_BOOTCOUNT_RAM
2367 enable support for the bootcounter in RAM
2368 CONFIG_BOOTCOUNT_I2C
2369 enable support for the bootcounter on an i2c (like RTC) device.
2370 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2371 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2373 CONFIG_BOOTCOUNT_ALEN = address len
2375 - Show boot progress:
2376 CONFIG_SHOW_BOOT_PROGRESS
2378 Defining this option allows to add some board-
2379 specific code (calling a user-provided function
2380 "show_boot_progress(int)") that enables you to show
2381 the system's boot progress on some display (for
2382 example, some LED's) on your board. At the moment,
2383 the following checkpoints are implemented:
2386 Legacy uImage format:
2389 1 common/cmd_bootm.c before attempting to boot an image
2390 -1 common/cmd_bootm.c Image header has bad magic number
2391 2 common/cmd_bootm.c Image header has correct magic number
2392 -2 common/cmd_bootm.c Image header has bad checksum
2393 3 common/cmd_bootm.c Image header has correct checksum
2394 -3 common/cmd_bootm.c Image data has bad checksum
2395 4 common/cmd_bootm.c Image data has correct checksum
2396 -4 common/cmd_bootm.c Image is for unsupported architecture
2397 5 common/cmd_bootm.c Architecture check OK
2398 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2399 6 common/cmd_bootm.c Image Type check OK
2400 -6 common/cmd_bootm.c gunzip uncompression error
2401 -7 common/cmd_bootm.c Unimplemented compression type
2402 7 common/cmd_bootm.c Uncompression OK
2403 8 common/cmd_bootm.c No uncompress/copy overwrite error
2404 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2406 9 common/image.c Start initial ramdisk verification
2407 -10 common/image.c Ramdisk header has bad magic number
2408 -11 common/image.c Ramdisk header has bad checksum
2409 10 common/image.c Ramdisk header is OK
2410 -12 common/image.c Ramdisk data has bad checksum
2411 11 common/image.c Ramdisk data has correct checksum
2412 12 common/image.c Ramdisk verification complete, start loading
2413 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2414 13 common/image.c Start multifile image verification
2415 14 common/image.c No initial ramdisk, no multifile, continue.
2417 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2419 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2420 -31 post/post.c POST test failed, detected by post_output_backlog()
2421 -32 post/post.c POST test failed, detected by post_run_single()
2423 34 common/cmd_doc.c before loading a Image from a DOC device
2424 -35 common/cmd_doc.c Bad usage of "doc" command
2425 35 common/cmd_doc.c correct usage of "doc" command
2426 -36 common/cmd_doc.c No boot device
2427 36 common/cmd_doc.c correct boot device
2428 -37 common/cmd_doc.c Unknown Chip ID on boot device
2429 37 common/cmd_doc.c correct chip ID found, device available
2430 -38 common/cmd_doc.c Read Error on boot device
2431 38 common/cmd_doc.c reading Image header from DOC device OK
2432 -39 common/cmd_doc.c Image header has bad magic number
2433 39 common/cmd_doc.c Image header has correct magic number
2434 -40 common/cmd_doc.c Error reading Image from DOC device
2435 40 common/cmd_doc.c Image header has correct magic number
2436 41 common/cmd_ide.c before loading a Image from a IDE device
2437 -42 common/cmd_ide.c Bad usage of "ide" command
2438 42 common/cmd_ide.c correct usage of "ide" command
2439 -43 common/cmd_ide.c No boot device
2440 43 common/cmd_ide.c boot device found
2441 -44 common/cmd_ide.c Device not available
2442 44 common/cmd_ide.c Device available
2443 -45 common/cmd_ide.c wrong partition selected
2444 45 common/cmd_ide.c partition selected
2445 -46 common/cmd_ide.c Unknown partition table
2446 46 common/cmd_ide.c valid partition table found
2447 -47 common/cmd_ide.c Invalid partition type
2448 47 common/cmd_ide.c correct partition type
2449 -48 common/cmd_ide.c Error reading Image Header on boot device
2450 48 common/cmd_ide.c reading Image Header from IDE device OK
2451 -49 common/cmd_ide.c Image header has bad magic number
2452 49 common/cmd_ide.c Image header has correct magic number
2453 -50 common/cmd_ide.c Image header has bad checksum
2454 50 common/cmd_ide.c Image header has correct checksum
2455 -51 common/cmd_ide.c Error reading Image from IDE device
2456 51 common/cmd_ide.c reading Image from IDE device OK
2457 52 common/cmd_nand.c before loading a Image from a NAND device
2458 -53 common/cmd_nand.c Bad usage of "nand" command
2459 53 common/cmd_nand.c correct usage of "nand" command
2460 -54 common/cmd_nand.c No boot device
2461 54 common/cmd_nand.c boot device found
2462 -55 common/cmd_nand.c Unknown Chip ID on boot device
2463 55 common/cmd_nand.c correct chip ID found, device available
2464 -56 common/cmd_nand.c Error reading Image Header on boot device
2465 56 common/cmd_nand.c reading Image Header from NAND device OK
2466 -57 common/cmd_nand.c Image header has bad magic number
2467 57 common/cmd_nand.c Image header has correct magic number
2468 -58 common/cmd_nand.c Error reading Image from NAND device
2469 58 common/cmd_nand.c reading Image from NAND device OK
2471 -60 common/env_common.c Environment has a bad CRC, using default
2473 64 net/eth.c starting with Ethernet configuration.
2474 -64 net/eth.c no Ethernet found.
2475 65 net/eth.c Ethernet found.
2477 -80 common/cmd_net.c usage wrong
2478 80 common/cmd_net.c before calling net_loop()
2479 -81 common/cmd_net.c some error in net_loop() occurred
2480 81 common/cmd_net.c net_loop() back without error
2481 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2482 82 common/cmd_net.c trying automatic boot
2483 83 common/cmd_net.c running "source" command
2484 -83 common/cmd_net.c some error in automatic boot or "source" command
2485 84 common/cmd_net.c end without errors
2490 100 common/cmd_bootm.c Kernel FIT Image has correct format
2491 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2492 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2493 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2494 102 common/cmd_bootm.c Kernel unit name specified
2495 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2496 103 common/cmd_bootm.c Found configuration node
2497 104 common/cmd_bootm.c Got kernel subimage node offset
2498 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2499 105 common/cmd_bootm.c Kernel subimage hash verification OK
2500 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2501 106 common/cmd_bootm.c Architecture check OK
2502 -106 common/cmd_bootm.c Kernel subimage has wrong type
2503 107 common/cmd_bootm.c Kernel subimage type OK
2504 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2505 108 common/cmd_bootm.c Got kernel subimage data/size
2506 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2507 -109 common/cmd_bootm.c Can't get kernel subimage type
2508 -110 common/cmd_bootm.c Can't get kernel subimage comp
2509 -111 common/cmd_bootm.c Can't get kernel subimage os
2510 -112 common/cmd_bootm.c Can't get kernel subimage load address
2511 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2513 120 common/image.c Start initial ramdisk verification
2514 -120 common/image.c Ramdisk FIT image has incorrect format
2515 121 common/image.c Ramdisk FIT image has correct format
2516 122 common/image.c No ramdisk subimage unit name, using configuration
2517 -122 common/image.c Can't get configuration for ramdisk subimage
2518 123 common/image.c Ramdisk unit name specified
2519 -124 common/image.c Can't get ramdisk subimage node offset
2520 125 common/image.c Got ramdisk subimage node offset
2521 -125 common/image.c Ramdisk subimage hash verification failed
2522 126 common/image.c Ramdisk subimage hash verification OK
2523 -126 common/image.c Ramdisk subimage for unsupported architecture
2524 127 common/image.c Architecture check OK
2525 -127 common/image.c Can't get ramdisk subimage data/size
2526 128 common/image.c Got ramdisk subimage data/size
2527 129 common/image.c Can't get ramdisk load address
2528 -129 common/image.c Got ramdisk load address
2530 -130 common/cmd_doc.c Incorrect FIT image format
2531 131 common/cmd_doc.c FIT image format OK
2533 -140 common/cmd_ide.c Incorrect FIT image format
2534 141 common/cmd_ide.c FIT image format OK
2536 -150 common/cmd_nand.c Incorrect FIT image format
2537 151 common/cmd_nand.c FIT image format OK
2539 - legacy image format:
2540 CONFIG_IMAGE_FORMAT_LEGACY
2541 enables the legacy image format support in U-Boot.
2544 enabled if CONFIG_FIT_SIGNATURE is not defined.
2546 CONFIG_DISABLE_IMAGE_LEGACY
2547 disable the legacy image format
2549 This define is introduced, as the legacy image format is
2550 enabled per default for backward compatibility.
2552 - Standalone program support:
2553 CONFIG_STANDALONE_LOAD_ADDR
2555 This option defines a board specific value for the
2556 address where standalone program gets loaded, thus
2557 overwriting the architecture dependent default
2560 - Frame Buffer Address:
2563 Define CONFIG_FB_ADDR if you want to use specific
2564 address for frame buffer. This is typically the case
2565 when using a graphics controller has separate video
2566 memory. U-Boot will then place the frame buffer at
2567 the given address instead of dynamically reserving it
2568 in system RAM by calling lcd_setmem(), which grabs
2569 the memory for the frame buffer depending on the
2570 configured panel size.
2572 Please see board_init_f function.
2574 - Automatic software updates via TFTP server
2576 CONFIG_UPDATE_TFTP_CNT_MAX
2577 CONFIG_UPDATE_TFTP_MSEC_MAX
2579 These options enable and control the auto-update feature;
2580 for a more detailed description refer to doc/README.update.
2582 - MTD Support (mtdparts command, UBI support)
2585 Adds the MTD device infrastructure from the Linux kernel.
2586 Needed for mtdparts command support.
2588 CONFIG_MTD_PARTITIONS
2590 Adds the MTD partitioning infrastructure from the Linux
2591 kernel. Needed for UBI support.
2594 CONFIG_UBI_SILENCE_MSG
2596 Make the verbose messages from UBI stop printing. This leaves
2597 warnings and errors enabled.
2600 CONFIG_MTD_UBI_WL_THRESHOLD
2601 This parameter defines the maximum difference between the highest
2602 erase counter value and the lowest erase counter value of eraseblocks
2603 of UBI devices. When this threshold is exceeded, UBI starts performing
2604 wear leveling by means of moving data from eraseblock with low erase
2605 counter to eraseblocks with high erase counter.
2607 The default value should be OK for SLC NAND flashes, NOR flashes and
2608 other flashes which have eraseblock life-cycle 100000 or more.
2609 However, in case of MLC NAND flashes which typically have eraseblock
2610 life-cycle less than 10000, the threshold should be lessened (e.g.,
2611 to 128 or 256, although it does not have to be power of 2).
2615 CONFIG_MTD_UBI_BEB_LIMIT
2616 This option specifies the maximum bad physical eraseblocks UBI
2617 expects on the MTD device (per 1024 eraseblocks). If the
2618 underlying flash does not admit of bad eraseblocks (e.g. NOR
2619 flash), this value is ignored.
2621 NAND datasheets often specify the minimum and maximum NVM
2622 (Number of Valid Blocks) for the flashes' endurance lifetime.
2623 The maximum expected bad eraseblocks per 1024 eraseblocks
2624 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2625 which gives 20 for most NANDs (MaxNVB is basically the total
2626 count of eraseblocks on the chip).
2628 To put it differently, if this value is 20, UBI will try to
2629 reserve about 1.9% of physical eraseblocks for bad blocks
2630 handling. And that will be 1.9% of eraseblocks on the entire
2631 NAND chip, not just the MTD partition UBI attaches. This means
2632 that if you have, say, a NAND flash chip admits maximum 40 bad
2633 eraseblocks, and it is split on two MTD partitions of the same
2634 size, UBI will reserve 40 eraseblocks when attaching a
2639 CONFIG_MTD_UBI_FASTMAP
2640 Fastmap is a mechanism which allows attaching an UBI device
2641 in nearly constant time. Instead of scanning the whole MTD device it
2642 only has to locate a checkpoint (called fastmap) on the device.
2643 The on-flash fastmap contains all information needed to attach
2644 the device. Using fastmap makes only sense on large devices where
2645 attaching by scanning takes long. UBI will not automatically install
2646 a fastmap on old images, but you can set the UBI parameter
2647 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2648 that fastmap-enabled images are still usable with UBI implementations
2649 without fastmap support. On typical flash devices the whole fastmap
2650 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2652 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2653 Set this parameter to enable fastmap automatically on images
2657 CONFIG_MTD_UBI_FM_DEBUG
2658 Enable UBI fastmap debug
2662 CONFIG_UBIFS_SILENCE_MSG
2664 Make the verbose messages from UBIFS stop printing. This leaves
2665 warnings and errors enabled.
2669 Enable building of SPL globally.
2672 LDSCRIPT for linking the SPL binary.
2674 CONFIG_SPL_MAX_FOOTPRINT
2675 Maximum size in memory allocated to the SPL, BSS included.
2676 When defined, the linker checks that the actual memory
2677 used by SPL from _start to __bss_end does not exceed it.
2678 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2679 must not be both defined at the same time.
2682 Maximum size of the SPL image (text, data, rodata, and
2683 linker lists sections), BSS excluded.
2684 When defined, the linker checks that the actual size does
2687 CONFIG_SPL_TEXT_BASE
2688 TEXT_BASE for linking the SPL binary.
2690 CONFIG_SPL_RELOC_TEXT_BASE
2691 Address to relocate to. If unspecified, this is equal to
2692 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2694 CONFIG_SPL_BSS_START_ADDR
2695 Link address for the BSS within the SPL binary.
2697 CONFIG_SPL_BSS_MAX_SIZE
2698 Maximum size in memory allocated to the SPL BSS.
2699 When defined, the linker checks that the actual memory used
2700 by SPL from __bss_start to __bss_end does not exceed it.
2701 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2702 must not be both defined at the same time.
2705 Adress of the start of the stack SPL will use
2707 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2708 When defined, SPL will panic() if the image it has
2709 loaded does not have a signature.
2710 Defining this is useful when code which loads images
2711 in SPL cannot guarantee that absolutely all read errors
2713 An example is the LPC32XX MLC NAND driver, which will
2714 consider that a completely unreadable NAND block is bad,
2715 and thus should be skipped silently.
2717 CONFIG_SPL_RELOC_STACK
2718 Adress of the start of the stack SPL will use after
2719 relocation. If unspecified, this is equal to
2722 CONFIG_SYS_SPL_MALLOC_START
2723 Starting address of the malloc pool used in SPL.
2724 When this option is set the full malloc is used in SPL and
2725 it is set up by spl_init() and before that, the simple malloc()
2726 can be used if CONFIG_SYS_MALLOC_F is defined.
2728 CONFIG_SYS_SPL_MALLOC_SIZE
2729 The size of the malloc pool used in SPL.
2731 CONFIG_SPL_FRAMEWORK
2732 Enable the SPL framework under common/. This framework
2733 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2734 NAND loading of the Linux Kernel.
2737 Enable booting directly to an OS from SPL.
2738 See also: doc/README.falcon
2740 CONFIG_SPL_DISPLAY_PRINT
2741 For ARM, enable an optional function to print more information
2742 about the running system.
2744 CONFIG_SPL_INIT_MINIMAL
2745 Arch init code should be built for a very small image
2747 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2748 Partition on the MMC to load U-Boot from when the MMC is being
2751 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2752 Sector to load kernel uImage from when MMC is being
2753 used in raw mode (for Falcon mode)
2755 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2756 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2757 Sector and number of sectors to load kernel argument
2758 parameters from when MMC is being used in raw mode
2761 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2762 Partition on the MMC to load U-Boot from when the MMC is being
2765 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2766 Filename to read to load U-Boot when reading from filesystem
2768 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2769 Filename to read to load kernel uImage when reading
2770 from filesystem (for Falcon mode)
2772 CONFIG_SPL_FS_LOAD_ARGS_NAME
2773 Filename to read to load kernel argument parameters
2774 when reading from filesystem (for Falcon mode)
2776 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2777 Set this for NAND SPL on PPC mpc83xx targets, so that
2778 start.S waits for the rest of the SPL to load before
2779 continuing (the hardware starts execution after just
2780 loading the first page rather than the full 4K).
2782 CONFIG_SPL_SKIP_RELOCATE
2783 Avoid SPL relocation
2785 CONFIG_SPL_NAND_BASE
2786 Include nand_base.c in the SPL. Requires
2787 CONFIG_SPL_NAND_DRIVERS.
2789 CONFIG_SPL_NAND_DRIVERS
2790 SPL uses normal NAND drivers, not minimal drivers.
2793 Include standard software ECC in the SPL
2795 CONFIG_SPL_NAND_SIMPLE
2796 Support for NAND boot using simple NAND drivers that
2797 expose the cmd_ctrl() interface.
2800 Support for a lightweight UBI (fastmap) scanner and
2803 CONFIG_SPL_NAND_RAW_ONLY
2804 Support to boot only raw u-boot.bin images. Use this only
2805 if you need to save space.
2807 CONFIG_SPL_COMMON_INIT_DDR
2808 Set for common ddr init with serial presence detect in
2811 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2812 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2813 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2814 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2815 CONFIG_SYS_NAND_ECCBYTES
2816 Defines the size and behavior of the NAND that SPL uses
2819 CONFIG_SPL_NAND_BOOT
2820 Add support NAND boot
2822 CONFIG_SYS_NAND_U_BOOT_OFFS
2823 Location in NAND to read U-Boot from
2825 CONFIG_SYS_NAND_U_BOOT_DST
2826 Location in memory to load U-Boot to
2828 CONFIG_SYS_NAND_U_BOOT_SIZE
2829 Size of image to load
2831 CONFIG_SYS_NAND_U_BOOT_START
2832 Entry point in loaded image to jump to
2834 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2835 Define this if you need to first read the OOB and then the
2836 data. This is used, for example, on davinci platforms.
2838 CONFIG_SPL_OMAP3_ID_NAND
2839 Support for an OMAP3-specific set of functions to return the
2840 ID and MFR of the first attached NAND chip, if present.
2842 CONFIG_SPL_RAM_DEVICE
2843 Support for running image already present in ram, in SPL binary
2846 Image offset to which the SPL should be padded before appending
2847 the SPL payload. By default, this is defined as
2848 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2849 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2850 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2853 Final target image containing SPL and payload. Some SPLs
2854 use an arch-specific makefile fragment instead, for
2855 example if more than one image needs to be produced.
2857 CONFIG_FIT_SPL_PRINT
2858 Printing information about a FIT image adds quite a bit of
2859 code to SPL. So this is normally disabled in SPL. Use this
2860 option to re-enable it. This will affect the output of the
2861 bootm command when booting a FIT image.
2865 Enable building of TPL globally.
2868 Image offset to which the TPL should be padded before appending
2869 the TPL payload. By default, this is defined as
2870 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2871 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2872 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2874 - Interrupt support (PPC):
2876 There are common interrupt_init() and timer_interrupt()
2877 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2878 for CPU specific initialization. interrupt_init_cpu()
2879 should set decrementer_count to appropriate value. If
2880 CPU resets decrementer automatically after interrupt
2881 (ppc4xx) it should set decrementer_count to zero.
2882 timer_interrupt() calls timer_interrupt_cpu() for CPU
2883 specific handling. If board has watchdog / status_led
2884 / other_activity_monitor it works automatically from
2885 general timer_interrupt().
2888 Board initialization settings:
2889 ------------------------------
2891 During Initialization u-boot calls a number of board specific functions
2892 to allow the preparation of board specific prerequisites, e.g. pin setup
2893 before drivers are initialized. To enable these callbacks the
2894 following configuration macros have to be defined. Currently this is
2895 architecture specific, so please check arch/your_architecture/lib/board.c
2896 typically in board_init_f() and board_init_r().
2898 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2899 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2900 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2901 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2903 Configuration Settings:
2904 -----------------------
2906 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
2907 Optionally it can be defined to support 64-bit memory commands.
2909 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2910 undefine this when you're short of memory.
2912 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2913 width of the commands listed in the 'help' command output.
2915 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2916 prompt for user input.
2918 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2920 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2922 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2924 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2925 the application (usually a Linux kernel) when it is
2928 - CONFIG_SYS_BAUDRATE_TABLE:
2929 List of legal baudrate settings for this board.
2931 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2932 Begin and End addresses of the area used by the
2935 - CONFIG_SYS_ALT_MEMTEST:
2936 Enable an alternate, more extensive memory test.
2938 - CONFIG_SYS_MEMTEST_SCRATCH:
2939 Scratch address used by the alternate memory test
2940 You only need to set this if address zero isn't writeable
2942 - CONFIG_SYS_MEM_RESERVE_SECURE
2943 Only implemented for ARMv8 for now.
2944 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
2945 is substracted from total RAM and won't be reported to OS.
2946 This memory can be used as secure memory. A variable
2947 gd->arch.secure_ram is used to track the location. In systems
2948 the RAM base is not zero, or RAM is divided into banks,
2949 this variable needs to be recalcuated to get the address.
2951 - CONFIG_SYS_MEM_TOP_HIDE:
2952 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2953 this specified memory area will get subtracted from the top
2954 (end) of RAM and won't get "touched" at all by U-Boot. By
2955 fixing up gd->ram_size the Linux kernel should gets passed
2956 the now "corrected" memory size and won't touch it either.
2957 This should work for arch/ppc and arch/powerpc. Only Linux
2958 board ports in arch/powerpc with bootwrapper support that
2959 recalculate the memory size from the SDRAM controller setup
2960 will have to get fixed in Linux additionally.
2962 This option can be used as a workaround for the 440EPx/GRx
2963 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2966 WARNING: Please make sure that this value is a multiple of
2967 the Linux page size (normally 4k). If this is not the case,
2968 then the end address of the Linux memory will be located at a
2969 non page size aligned address and this could cause major
2972 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2973 Enable temporary baudrate change while serial download
2975 - CONFIG_SYS_SDRAM_BASE:
2976 Physical start address of SDRAM. _Must_ be 0 here.
2978 - CONFIG_SYS_FLASH_BASE:
2979 Physical start address of Flash memory.
2981 - CONFIG_SYS_MONITOR_BASE:
2982 Physical start address of boot monitor code (set by
2983 make config files to be same as the text base address
2984 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2985 CONFIG_SYS_FLASH_BASE when booting from flash.
2987 - CONFIG_SYS_MONITOR_LEN:
2988 Size of memory reserved for monitor code, used to
2989 determine _at_compile_time_ (!) if the environment is
2990 embedded within the U-Boot image, or in a separate
2993 - CONFIG_SYS_MALLOC_LEN:
2994 Size of DRAM reserved for malloc() use.
2996 - CONFIG_SYS_MALLOC_F_LEN
2997 Size of the malloc() pool for use before relocation. If
2998 this is defined, then a very simple malloc() implementation
2999 will become available before relocation. The address is just
3000 below the global data, and the stack is moved down to make
3003 This feature allocates regions with increasing addresses
3004 within the region. calloc() is supported, but realloc()
3005 is not available. free() is supported but does nothing.
3006 The memory will be freed (or in fact just forgotten) when
3007 U-Boot relocates itself.
3009 - CONFIG_SYS_MALLOC_SIMPLE
3010 Provides a simple and small malloc() and calloc() for those
3011 boards which do not use the full malloc in SPL (which is
3012 enabled with CONFIG_SYS_SPL_MALLOC_START).
3014 - CONFIG_SYS_NONCACHED_MEMORY:
3015 Size of non-cached memory area. This area of memory will be
3016 typically located right below the malloc() area and mapped
3017 uncached in the MMU. This is useful for drivers that would
3018 otherwise require a lot of explicit cache maintenance. For
3019 some drivers it's also impossible to properly maintain the
3020 cache. For example if the regions that need to be flushed
3021 are not a multiple of the cache-line size, *and* padding
3022 cannot be allocated between the regions to align them (i.e.
3023 if the HW requires a contiguous array of regions, and the
3024 size of each region is not cache-aligned), then a flush of
3025 one region may result in overwriting data that hardware has
3026 written to another region in the same cache-line. This can
3027 happen for example in network drivers where descriptors for
3028 buffers are typically smaller than the CPU cache-line (e.g.
3029 16 bytes vs. 32 or 64 bytes).
3031 Non-cached memory is only supported on 32-bit ARM at present.
3033 - CONFIG_SYS_BOOTM_LEN:
3034 Normally compressed uImages are limited to an
3035 uncompressed size of 8 MBytes. If this is not enough,
3036 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3037 to adjust this setting to your needs.
3039 - CONFIG_SYS_BOOTMAPSZ:
3040 Maximum size of memory mapped by the startup code of
3041 the Linux kernel; all data that must be processed by
3042 the Linux kernel (bd_info, boot arguments, FDT blob if
3043 used) must be put below this limit, unless "bootm_low"
3044 environment variable is defined and non-zero. In such case
3045 all data for the Linux kernel must be between "bootm_low"
3046 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3047 variable "bootm_mapsize" will override the value of
3048 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3049 then the value in "bootm_size" will be used instead.
3051 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3052 Enable initrd_high functionality. If defined then the
3053 initrd_high feature is enabled and the bootm ramdisk subcommand
3056 - CONFIG_SYS_BOOT_GET_CMDLINE:
3057 Enables allocating and saving kernel cmdline in space between
3058 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3060 - CONFIG_SYS_BOOT_GET_KBD:
3061 Enables allocating and saving a kernel copy of the bd_info in
3062 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3064 - CONFIG_SYS_MAX_FLASH_BANKS:
3065 Max number of Flash memory banks
3067 - CONFIG_SYS_MAX_FLASH_SECT:
3068 Max number of sectors on a Flash chip
3070 - CONFIG_SYS_FLASH_ERASE_TOUT:
3071 Timeout for Flash erase operations (in ms)
3073 - CONFIG_SYS_FLASH_WRITE_TOUT:
3074 Timeout for Flash write operations (in ms)
3076 - CONFIG_SYS_FLASH_LOCK_TOUT
3077 Timeout for Flash set sector lock bit operation (in ms)
3079 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3080 Timeout for Flash clear lock bits operation (in ms)
3082 - CONFIG_SYS_FLASH_PROTECTION
3083 If defined, hardware flash sectors protection is used
3084 instead of U-Boot software protection.
3086 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3088 Enable TFTP transfers directly to flash memory;
3089 without this option such a download has to be
3090 performed in two steps: (1) download to RAM, and (2)
3091 copy from RAM to flash.
3093 The two-step approach is usually more reliable, since
3094 you can check if the download worked before you erase
3095 the flash, but in some situations (when system RAM is
3096 too limited to allow for a temporary copy of the
3097 downloaded image) this option may be very useful.
3099 - CONFIG_SYS_FLASH_CFI:
3100 Define if the flash driver uses extra elements in the
3101 common flash structure for storing flash geometry.
3103 - CONFIG_FLASH_CFI_DRIVER
3104 This option also enables the building of the cfi_flash driver
3105 in the drivers directory
3107 - CONFIG_FLASH_CFI_MTD
3108 This option enables the building of the cfi_mtd driver
3109 in the drivers directory. The driver exports CFI flash
3112 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3113 Use buffered writes to flash.
3115 - CONFIG_FLASH_SPANSION_S29WS_N
3116 s29ws-n MirrorBit flash has non-standard addresses for buffered
3119 - CONFIG_SYS_FLASH_QUIET_TEST
3120 If this option is defined, the common CFI flash doesn't
3121 print it's warning upon not recognized FLASH banks. This
3122 is useful, if some of the configured banks are only
3123 optionally available.
3125 - CONFIG_FLASH_SHOW_PROGRESS
3126 If defined (must be an integer), print out countdown
3127 digits and dots. Recommended value: 45 (9..1) for 80
3128 column displays, 15 (3..1) for 40 column displays.
3130 - CONFIG_FLASH_VERIFY
3131 If defined, the content of the flash (destination) is compared
3132 against the source after the write operation. An error message
3133 will be printed when the contents are not identical.
3134 Please note that this option is useless in nearly all cases,
3135 since such flash programming errors usually are detected earlier
3136 while unprotecting/erasing/programming. Please only enable
3137 this option if you really know what you are doing.
3139 - CONFIG_SYS_RX_ETH_BUFFER:
3140 Defines the number of Ethernet receive buffers. On some
3141 Ethernet controllers it is recommended to set this value
3142 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3143 buffers can be full shortly after enabling the interface
3144 on high Ethernet traffic.
3145 Defaults to 4 if not defined.
3147 - CONFIG_ENV_MAX_ENTRIES
3149 Maximum number of entries in the hash table that is used
3150 internally to store the environment settings. The default
3151 setting is supposed to be generous and should work in most
3152 cases. This setting can be used to tune behaviour; see
3153 lib/hashtable.c for details.
3155 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3156 - CONFIG_ENV_FLAGS_LIST_STATIC
3157 Enable validation of the values given to environment variables when
3158 calling env set. Variables can be restricted to only decimal,
3159 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3160 the variables can also be restricted to IP address or MAC address.
3162 The format of the list is:
3163 type_attribute = [s|d|x|b|i|m]
3164 access_attribute = [a|r|o|c]
3165 attributes = type_attribute[access_attribute]
3166 entry = variable_name[:attributes]
3169 The type attributes are:
3170 s - String (default)
3173 b - Boolean ([1yYtT|0nNfF])
3177 The access attributes are:
3183 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3184 Define this to a list (string) to define the ".flags"
3185 environment variable in the default or embedded environment.
3187 - CONFIG_ENV_FLAGS_LIST_STATIC
3188 Define this to a list (string) to define validation that
3189 should be done if an entry is not found in the ".flags"
3190 environment variable. To override a setting in the static
3191 list, simply add an entry for the same variable name to the
3194 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3195 regular expression. This allows multiple variables to define the same
3196 flags without explicitly listing them for each variable.
3198 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3199 If defined, don't allow the -f switch to env set override variable
3203 If stdint.h is available with your toolchain you can define this
3204 option to enable it. You can provide option 'USE_STDINT=1' when
3205 building U-Boot to enable this.
3207 The following definitions that deal with the placement and management
3208 of environment data (variable area); in general, we support the
3209 following configurations:
3211 - CONFIG_BUILD_ENVCRC:
3213 Builds up envcrc with the target environment so that external utils
3214 may easily extract it and embed it in final U-Boot images.
3216 BE CAREFUL! The first access to the environment happens quite early
3217 in U-Boot initialization (when we try to get the setting of for the
3218 console baudrate). You *MUST* have mapped your NVRAM area then, or
3221 Please note that even with NVRAM we still use a copy of the
3222 environment in RAM: we could work on NVRAM directly, but we want to
3223 keep settings there always unmodified except somebody uses "saveenv"
3224 to save the current settings.
3226 BE CAREFUL! For some special cases, the local device can not use
3227 "saveenv" command. For example, the local device will get the
3228 environment stored in a remote NOR flash by SRIO or PCIE link,
3229 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3231 - CONFIG_NAND_ENV_DST
3233 Defines address in RAM to which the nand_spl code should copy the
3234 environment. If redundant environment is used, it will be copied to
3235 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3237 Please note that the environment is read-only until the monitor
3238 has been relocated to RAM and a RAM copy of the environment has been
3239 created; also, when using EEPROM you will have to use env_get_f()
3240 until then to read environment variables.
3242 The environment is protected by a CRC32 checksum. Before the monitor
3243 is relocated into RAM, as a result of a bad CRC you will be working
3244 with the compiled-in default environment - *silently*!!! [This is
3245 necessary, because the first environment variable we need is the
3246 "baudrate" setting for the console - if we have a bad CRC, we don't
3247 have any device yet where we could complain.]
3249 Note: once the monitor has been relocated, then it will complain if
3250 the default environment is used; a new CRC is computed as soon as you
3251 use the "saveenv" command to store a valid environment.
3253 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3254 Echo the inverted Ethernet link state to the fault LED.
3256 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3257 also needs to be defined.
3259 - CONFIG_SYS_FAULT_MII_ADDR:
3260 MII address of the PHY to check for the Ethernet link state.
3262 - CONFIG_NS16550_MIN_FUNCTIONS:
3263 Define this if you desire to only have use of the NS16550_init
3264 and NS16550_putc functions for the serial driver located at
3265 drivers/serial/ns16550.c. This option is useful for saving
3266 space for already greatly restricted images, including but not
3267 limited to NAND_SPL configurations.
3269 - CONFIG_DISPLAY_BOARDINFO
3270 Display information about the board that U-Boot is running on
3271 when U-Boot starts up. The board function checkboard() is called
3274 - CONFIG_DISPLAY_BOARDINFO_LATE
3275 Similar to the previous option, but display this information
3276 later, once stdio is running and output goes to the LCD, if
3279 - CONFIG_BOARD_SIZE_LIMIT:
3280 Maximum size of the U-Boot image. When defined, the
3281 build system checks that the actual size does not
3284 Low Level (hardware related) configuration options:
3285 ---------------------------------------------------
3287 - CONFIG_SYS_CACHELINE_SIZE:
3288 Cache Line Size of the CPU.
3290 - CONFIG_SYS_CCSRBAR_DEFAULT:
3291 Default (power-on reset) physical address of CCSR on Freescale
3294 - CONFIG_SYS_CCSRBAR:
3295 Virtual address of CCSR. On a 32-bit build, this is typically
3296 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3298 - CONFIG_SYS_CCSRBAR_PHYS:
3299 Physical address of CCSR. CCSR can be relocated to a new
3300 physical address, if desired. In this case, this macro should
3301 be set to that address. Otherwise, it should be set to the
3302 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3303 is typically relocated on 36-bit builds. It is recommended
3304 that this macro be defined via the _HIGH and _LOW macros:
3306 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3307 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3309 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3310 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3311 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3312 used in assembly code, so it must not contain typecasts or
3313 integer size suffixes (e.g. "ULL").
3315 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3316 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3317 used in assembly code, so it must not contain typecasts or
3318 integer size suffixes (e.g. "ULL").
3320 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3321 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3322 forced to a value that ensures that CCSR is not relocated.
3324 - Floppy Disk Support:
3325 CONFIG_SYS_FDC_DRIVE_NUMBER
3327 the default drive number (default value 0)
3329 CONFIG_SYS_ISA_IO_STRIDE
3331 defines the spacing between FDC chipset registers
3334 CONFIG_SYS_ISA_IO_OFFSET
3336 defines the offset of register from address. It
3337 depends on which part of the data bus is connected to
3338 the FDC chipset. (default value 0)
3340 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3341 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3344 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3345 fdc_hw_init() is called at the beginning of the FDC
3346 setup. fdc_hw_init() must be provided by the board
3347 source code. It is used to make hardware-dependent
3351 Most IDE controllers were designed to be connected with PCI
3352 interface. Only few of them were designed for AHB interface.
3353 When software is doing ATA command and data transfer to
3354 IDE devices through IDE-AHB controller, some additional
3355 registers accessing to these kind of IDE-AHB controller
3358 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3359 DO NOT CHANGE unless you know exactly what you're
3360 doing! (11-4) [MPC8xx systems only]
3362 - CONFIG_SYS_INIT_RAM_ADDR:
3364 Start address of memory area that can be used for
3365 initial data and stack; please note that this must be
3366 writable memory that is working WITHOUT special
3367 initialization, i. e. you CANNOT use normal RAM which
3368 will become available only after programming the
3369 memory controller and running certain initialization
3372 U-Boot uses the following memory types:
3373 - MPC8xx: IMMR (internal memory of the CPU)
3375 - CONFIG_SYS_GBL_DATA_OFFSET:
3377 Offset of the initial data structure in the memory
3378 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3379 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3380 data is located at the end of the available space
3381 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3382 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3383 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3384 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3387 On the MPC824X (or other systems that use the data
3388 cache for initial memory) the address chosen for
3389 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3390 point to an otherwise UNUSED address space between
3391 the top of RAM and the start of the PCI space.
3393 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3395 - CONFIG_SYS_OR_TIMING_SDRAM:
3398 - CONFIG_SYS_MAMR_PTA:
3399 periodic timer for refresh
3401 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3402 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3403 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3404 CONFIG_SYS_BR1_PRELIM:
3405 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3407 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3408 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3409 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3410 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3412 - CONFIG_PCI_ENUM_ONLY
3413 Only scan through and get the devices on the buses.
3414 Don't do any setup work, presumably because someone or
3415 something has already done it, and we don't need to do it
3416 a second time. Useful for platforms that are pre-booted
3417 by coreboot or similar.
3419 - CONFIG_PCI_INDIRECT_BRIDGE:
3420 Enable support for indirect PCI bridges.
3423 Chip has SRIO or not
3426 Board has SRIO 1 port available
3429 Board has SRIO 2 port available
3431 - CONFIG_SRIO_PCIE_BOOT_MASTER
3432 Board can support master function for Boot from SRIO and PCIE
3434 - CONFIG_SYS_SRIOn_MEM_VIRT:
3435 Virtual Address of SRIO port 'n' memory region
3437 - CONFIG_SYS_SRIOn_MEM_PHYS:
3438 Physical Address of SRIO port 'n' memory region
3440 - CONFIG_SYS_SRIOn_MEM_SIZE:
3441 Size of SRIO port 'n' memory region
3443 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3444 Defined to tell the NAND controller that the NAND chip is using
3446 Not all NAND drivers use this symbol.
3447 Example of drivers that use it:
3448 - drivers/mtd/nand/ndfc.c
3449 - drivers/mtd/nand/mxc_nand.c
3451 - CONFIG_SYS_NDFC_EBC0_CFG
3452 Sets the EBC0_CFG register for the NDFC. If not defined
3453 a default value will be used.
3456 Get DDR timing information from an I2C EEPROM. Common
3457 with pluggable memory modules such as SODIMMs
3460 I2C address of the SPD EEPROM
3462 - CONFIG_SYS_SPD_BUS_NUM
3463 If SPD EEPROM is on an I2C bus other than the first
3464 one, specify here. Note that the value must resolve
3465 to something your driver can deal with.
3467 - CONFIG_SYS_DDR_RAW_TIMING
3468 Get DDR timing information from other than SPD. Common with
3469 soldered DDR chips onboard without SPD. DDR raw timing
3470 parameters are extracted from datasheet and hard-coded into
3471 header files or board specific files.
3473 - CONFIG_FSL_DDR_INTERACTIVE
3474 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3476 - CONFIG_FSL_DDR_SYNC_REFRESH
3477 Enable sync of refresh for multiple controllers.
3479 - CONFIG_FSL_DDR_BIST
3480 Enable built-in memory test for Freescale DDR controllers.
3482 - CONFIG_SYS_83XX_DDR_USES_CS0
3483 Only for 83xx systems. If specified, then DDR should
3484 be configured using CS0 and CS1 instead of CS2 and CS3.
3487 Enable RMII mode for all FECs.
3488 Note that this is a global option, we can't
3489 have one FEC in standard MII mode and another in RMII mode.
3491 - CONFIG_CRC32_VERIFY
3492 Add a verify option to the crc32 command.
3495 => crc32 -v <address> <count> <crc32>
3497 Where address/count indicate a memory area
3498 and crc32 is the correct crc32 which the
3502 Add the "loopw" memory command. This only takes effect if
3503 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3506 Add the "mdc" and "mwc" memory commands. These are cyclic
3511 This command will print 4 bytes (10,11,12,13) each 500 ms.
3513 => mwc.l 100 12345678 10
3514 This command will write 12345678 to address 100 all 10 ms.
3516 This only takes effect if the memory commands are activated
3517 globally (CONFIG_CMD_MEMORY).
3519 - CONFIG_SKIP_LOWLEVEL_INIT
3520 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3521 low level initializations (like setting up the memory
3522 controller) are omitted and/or U-Boot does not
3523 relocate itself into RAM.
3525 Normally this variable MUST NOT be defined. The only
3526 exception is when U-Boot is loaded (to RAM) by some
3527 other boot loader or by a debugger which performs
3528 these initializations itself.
3530 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3531 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3532 to be skipped. The normal CP15 init (such as enabling the
3533 instruction cache) is still performed.
3536 Modifies the behaviour of start.S when compiling a loader
3537 that is executed before the actual U-Boot. E.g. when
3538 compiling a NAND SPL.
3541 Modifies the behaviour of start.S when compiling a loader
3542 that is executed after the SPL and before the actual U-Boot.
3543 It is loaded by the SPL.
3545 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3546 Only for 85xx systems. If this variable is specified, the section
3547 .resetvec is not kept and the section .bootpg is placed in the
3548 previous 4k of the .text section.
3550 - CONFIG_ARCH_MAP_SYSMEM
3551 Generally U-Boot (and in particular the md command) uses
3552 effective address. It is therefore not necessary to regard
3553 U-Boot address as virtual addresses that need to be translated
3554 to physical addresses. However, sandbox requires this, since
3555 it maintains its own little RAM buffer which contains all
3556 addressable memory. This option causes some memory accesses
3557 to be mapped through map_sysmem() / unmap_sysmem().
3559 - CONFIG_X86_RESET_VECTOR
3560 If defined, the x86 reset vector code is included. This is not
3561 needed when U-Boot is running from Coreboot.
3563 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3564 Enables the RTC32K OSC on AM33xx based plattforms
3566 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3567 Option to disable subpage write in NAND driver
3568 driver that uses this:
3569 drivers/mtd/nand/davinci_nand.c
3571 Freescale QE/FMAN Firmware Support:
3572 -----------------------------------
3574 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3575 loading of "firmware", which is encoded in the QE firmware binary format.
3576 This firmware often needs to be loaded during U-Boot booting, so macros
3577 are used to identify the storage device (NOR flash, SPI, etc) and the address
3580 - CONFIG_SYS_FMAN_FW_ADDR
3581 The address in the storage device where the FMAN microcode is located. The
3582 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3585 - CONFIG_SYS_QE_FW_ADDR
3586 The address in the storage device where the QE microcode is located. The
3587 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3590 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3591 The maximum possible size of the firmware. The firmware binary format
3592 has a field that specifies the actual size of the firmware, but it
3593 might not be possible to read any part of the firmware unless some
3594 local storage is allocated to hold the entire firmware first.
3596 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3597 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3598 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3599 virtual address in NOR flash.
3601 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3602 Specifies that QE/FMAN firmware is located in NAND flash.
3603 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3605 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3606 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3607 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3609 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3610 Specifies that QE/FMAN firmware is located in the remote (master)
3611 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3612 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3613 window->master inbound window->master LAW->the ucode address in
3614 master's memory space.
3616 Freescale Layerscape Management Complex Firmware Support:
3617 ---------------------------------------------------------
3618 The Freescale Layerscape Management Complex (MC) supports the loading of
3620 This firmware often needs to be loaded during U-Boot booting, so macros
3621 are used to identify the storage device (NOR flash, SPI, etc) and the address
3624 - CONFIG_FSL_MC_ENET
3625 Enable the MC driver for Layerscape SoCs.
3627 Freescale Layerscape Debug Server Support:
3628 -------------------------------------------
3629 The Freescale Layerscape Debug Server Support supports the loading of
3630 "Debug Server firmware" and triggering SP boot-rom.
3631 This firmware often needs to be loaded during U-Boot booting.
3633 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3634 Define alignment of reserved memory MC requires
3639 In order to achieve reproducible builds, timestamps used in the U-Boot build
3640 process have to be set to a fixed value.
3642 This is done using the SOURCE_DATE_EPOCH environment variable.
3643 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3644 option for U-Boot or an environment variable in U-Boot.
3646 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3648 Building the Software:
3649 ======================
3651 Building U-Boot has been tested in several native build environments
3652 and in many different cross environments. Of course we cannot support
3653 all possibly existing versions of cross development tools in all
3654 (potentially obsolete) versions. In case of tool chain problems we
3655 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3656 which is extensively used to build and test U-Boot.
3658 If you are not using a native environment, it is assumed that you
3659 have GNU cross compiling tools available in your path. In this case,
3660 you must set the environment variable CROSS_COMPILE in your shell.
3661 Note that no changes to the Makefile or any other source files are
3662 necessary. For example using the ELDK on a 4xx CPU, please enter:
3664 $ CROSS_COMPILE=ppc_4xx-
3665 $ export CROSS_COMPILE
3667 Note: If you wish to generate Windows versions of the utilities in
3668 the tools directory you can use the MinGW toolchain
3669 (http://www.mingw.org). Set your HOST tools to the MinGW
3670 toolchain and execute 'make tools'. For example:
3672 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3674 Binaries such as tools/mkimage.exe will be created which can
3675 be executed on computers running Windows.
3677 U-Boot is intended to be simple to build. After installing the
3678 sources you must configure U-Boot for one specific board type. This
3683 where "NAME_defconfig" is the name of one of the existing configu-
3684 rations; see boards.cfg for supported names.
3686 Note: for some board special configuration names may exist; check if
3687 additional information is available from the board vendor; for
3688 instance, the TQM823L systems are available without (standard)
3689 or with LCD support. You can select such additional "features"
3690 when choosing the configuration, i. e.
3692 make TQM823L_defconfig
3693 - will configure for a plain TQM823L, i. e. no LCD support
3695 make TQM823L_LCD_defconfig
3696 - will configure for a TQM823L with U-Boot console on LCD
3701 Finally, type "make all", and you should get some working U-Boot
3702 images ready for download to / installation on your system:
3704 - "u-boot.bin" is a raw binary image
3705 - "u-boot" is an image in ELF binary format
3706 - "u-boot.srec" is in Motorola S-Record format
3708 By default the build is performed locally and the objects are saved
3709 in the source directory. One of the two methods can be used to change
3710 this behavior and build U-Boot to some external directory:
3712 1. Add O= to the make command line invocations:
3714 make O=/tmp/build distclean
3715 make O=/tmp/build NAME_defconfig
3716 make O=/tmp/build all
3718 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3720 export KBUILD_OUTPUT=/tmp/build
3725 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3729 Please be aware that the Makefiles assume you are using GNU make, so
3730 for instance on NetBSD you might need to use "gmake" instead of
3734 If the system board that you have is not listed, then you will need
3735 to port U-Boot to your hardware platform. To do this, follow these
3738 1. Create a new directory to hold your board specific code. Add any
3739 files you need. In your board directory, you will need at least
3740 the "Makefile" and a "<board>.c".
3741 2. Create a new configuration file "include/configs/<board>.h" for
3743 3. If you're porting U-Boot to a new CPU, then also create a new
3744 directory to hold your CPU specific code. Add any files you need.
3745 4. Run "make <board>_defconfig" with your new name.
3746 5. Type "make", and you should get a working "u-boot.srec" file
3747 to be installed on your target system.
3748 6. Debug and solve any problems that might arise.
3749 [Of course, this last step is much harder than it sounds.]
3752 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3753 ==============================================================
3755 If you have modified U-Boot sources (for instance added a new board
3756 or support for new devices, a new CPU, etc.) you are expected to
3757 provide feedback to the other developers. The feedback normally takes
3758 the form of a "patch", i. e. a context diff against a certain (latest
3759 official or latest in the git repository) version of U-Boot sources.
3761 But before you submit such a patch, please verify that your modifi-
3762 cation did not break existing code. At least make sure that *ALL* of
3763 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3764 just run the buildman script (tools/buildman/buildman), which will
3765 configure and build U-Boot for ALL supported system. Be warned, this
3766 will take a while. Please see the buildman README, or run 'buildman -H'
3770 See also "U-Boot Porting Guide" below.
3773 Monitor Commands - Overview:
3774 ============================
3776 go - start application at address 'addr'
3777 run - run commands in an environment variable
3778 bootm - boot application image from memory
3779 bootp - boot image via network using BootP/TFTP protocol
3780 bootz - boot zImage from memory
3781 tftpboot- boot image via network using TFTP protocol
3782 and env variables "ipaddr" and "serverip"
3783 (and eventually "gatewayip")
3784 tftpput - upload a file via network using TFTP protocol
3785 rarpboot- boot image via network using RARP/TFTP protocol
3786 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3787 loads - load S-Record file over serial line
3788 loadb - load binary file over serial line (kermit mode)
3790 mm - memory modify (auto-incrementing)
3791 nm - memory modify (constant address)
3792 mw - memory write (fill)
3794 cmp - memory compare
3795 crc32 - checksum calculation
3796 i2c - I2C sub-system
3797 sspi - SPI utility commands
3798 base - print or set address offset
3799 printenv- print environment variables
3800 setenv - set environment variables
3801 saveenv - save environment variables to persistent storage
3802 protect - enable or disable FLASH write protection
3803 erase - erase FLASH memory
3804 flinfo - print FLASH memory information
3805 nand - NAND memory operations (see doc/README.nand)
3806 bdinfo - print Board Info structure
3807 iminfo - print header information for application image
3808 coninfo - print console devices and informations
3809 ide - IDE sub-system
3810 loop - infinite loop on address range
3811 loopw - infinite write loop on address range
3812 mtest - simple RAM test
3813 icache - enable or disable instruction cache
3814 dcache - enable or disable data cache
3815 reset - Perform RESET of the CPU
3816 echo - echo args to console
3817 version - print monitor version
3818 help - print online help
3819 ? - alias for 'help'
3822 Monitor Commands - Detailed Description:
3823 ========================================
3827 For now: just type "help <command>".
3830 Environment Variables:
3831 ======================
3833 U-Boot supports user configuration using Environment Variables which
3834 can be made persistent by saving to Flash memory.
3836 Environment Variables are set using "setenv", printed using
3837 "printenv", and saved to Flash using "saveenv". Using "setenv"
3838 without a value can be used to delete a variable from the
3839 environment. As long as you don't save the environment you are
3840 working with an in-memory copy. In case the Flash area containing the
3841 environment is erased by accident, a default environment is provided.
3843 Some configuration options can be set using Environment Variables.
3845 List of environment variables (most likely not complete):
3847 baudrate - see CONFIG_BAUDRATE
3849 bootdelay - see CONFIG_BOOTDELAY
3851 bootcmd - see CONFIG_BOOTCOMMAND
3853 bootargs - Boot arguments when booting an RTOS image
3855 bootfile - Name of the image to load with TFTP
3857 bootm_low - Memory range available for image processing in the bootm
3858 command can be restricted. This variable is given as
3859 a hexadecimal number and defines lowest address allowed
3860 for use by the bootm command. See also "bootm_size"
3861 environment variable. Address defined by "bootm_low" is
3862 also the base of the initial memory mapping for the Linux
3863 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3866 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3867 This variable is given as a hexadecimal number and it
3868 defines the size of the memory region starting at base
3869 address bootm_low that is accessible by the Linux kernel
3870 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3871 as the default value if it is defined, and bootm_size is
3874 bootm_size - Memory range available for image processing in the bootm
3875 command can be restricted. This variable is given as
3876 a hexadecimal number and defines the size of the region
3877 allowed for use by the bootm command. See also "bootm_low"
3878 environment variable.
3880 updatefile - Location of the software update file on a TFTP server, used
3881 by the automatic software update feature. Please refer to
3882 documentation in doc/README.update for more details.
3884 autoload - if set to "no" (any string beginning with 'n'),
3885 "bootp" will just load perform a lookup of the
3886 configuration from the BOOTP server, but not try to
3887 load any image using TFTP
3889 autostart - if set to "yes", an image loaded using the "bootp",
3890 "rarpboot", "tftpboot" or "diskboot" commands will
3891 be automatically started (by internally calling
3894 If set to "no", a standalone image passed to the
3895 "bootm" command will be copied to the load address
3896 (and eventually uncompressed), but NOT be started.
3897 This can be used to load and uncompress arbitrary
3900 fdt_high - if set this restricts the maximum address that the
3901 flattened device tree will be copied into upon boot.
3902 For example, if you have a system with 1 GB memory
3903 at physical address 0x10000000, while Linux kernel
3904 only recognizes the first 704 MB as low memory, you
3905 may need to set fdt_high as 0x3C000000 to have the
3906 device tree blob be copied to the maximum address
3907 of the 704 MB low memory, so that Linux kernel can
3908 access it during the boot procedure.
3910 If this is set to the special value 0xFFFFFFFF then
3911 the fdt will not be copied at all on boot. For this
3912 to work it must reside in writable memory, have
3913 sufficient padding on the end of it for u-boot to
3914 add the information it needs into it, and the memory
3915 must be accessible by the kernel.
3917 fdtcontroladdr- if set this is the address of the control flattened
3918 device tree used by U-Boot when CONFIG_OF_CONTROL is
3921 i2cfast - (PPC405GP|PPC405EP only)
3922 if set to 'y' configures Linux I2C driver for fast
3923 mode (400kHZ). This environment variable is used in
3924 initialization code. So, for changes to be effective
3925 it must be saved and board must be reset.
3927 initrd_high - restrict positioning of initrd images:
3928 If this variable is not set, initrd images will be
3929 copied to the highest possible address in RAM; this
3930 is usually what you want since it allows for
3931 maximum initrd size. If for some reason you want to
3932 make sure that the initrd image is loaded below the
3933 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3934 variable to a value of "no" or "off" or "0".
3935 Alternatively, you can set it to a maximum upper
3936 address to use (U-Boot will still check that it
3937 does not overwrite the U-Boot stack and data).
3939 For instance, when you have a system with 16 MB
3940 RAM, and want to reserve 4 MB from use by Linux,
3941 you can do this by adding "mem=12M" to the value of
3942 the "bootargs" variable. However, now you must make
3943 sure that the initrd image is placed in the first
3944 12 MB as well - this can be done with
3946 setenv initrd_high 00c00000
3948 If you set initrd_high to 0xFFFFFFFF, this is an
3949 indication to U-Boot that all addresses are legal
3950 for the Linux kernel, including addresses in flash
3951 memory. In this case U-Boot will NOT COPY the
3952 ramdisk at all. This may be useful to reduce the
3953 boot time on your system, but requires that this
3954 feature is supported by your Linux kernel.
3956 ipaddr - IP address; needed for tftpboot command
3958 loadaddr - Default load address for commands like "bootp",
3959 "rarpboot", "tftpboot", "loadb" or "diskboot"
3961 loads_echo - see CONFIG_LOADS_ECHO
3963 serverip - TFTP server IP address; needed for tftpboot command
3965 bootretry - see CONFIG_BOOT_RETRY_TIME
3967 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3969 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3971 ethprime - controls which interface is used first.
3973 ethact - controls which interface is currently active.
3974 For example you can do the following
3976 => setenv ethact FEC
3977 => ping 192.168.0.1 # traffic sent on FEC
3978 => setenv ethact SCC
3979 => ping 10.0.0.1 # traffic sent on SCC
3981 ethrotate - When set to "no" U-Boot does not go through all
3982 available network interfaces.
3983 It just stays at the currently selected interface.
3985 netretry - When set to "no" each network operation will
3986 either succeed or fail without retrying.
3987 When set to "once" the network operation will
3988 fail when all the available network interfaces
3989 are tried once without success.
3990 Useful on scripts which control the retry operation
3993 npe_ucode - set load address for the NPE microcode
3995 silent_linux - If set then Linux will be told to boot silently, by
3996 changing the console to be empty. If "yes" it will be
3997 made silent. If "no" it will not be made silent. If
3998 unset, then it will be made silent if the U-Boot console
4001 tftpsrcp - If this is set, the value is used for TFTP's
4004 tftpdstp - If this is set, the value is used for TFTP's UDP
4005 destination port instead of the Well Know Port 69.
4007 tftpblocksize - Block size to use for TFTP transfers; if not set,
4008 we use the TFTP server's default block size
4010 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4011 seconds, minimum value is 1000 = 1 second). Defines
4012 when a packet is considered to be lost so it has to
4013 be retransmitted. The default is 5000 = 5 seconds.
4014 Lowering this value may make downloads succeed
4015 faster in networks with high packet loss rates or
4016 with unreliable TFTP servers.
4018 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4019 unit, minimum value = 0). Defines how many timeouts
4020 can happen during a single file transfer before that
4021 transfer is aborted. The default is 10, and 0 means
4022 'no timeouts allowed'. Increasing this value may help
4023 downloads succeed with high packet loss rates, or with
4024 unreliable TFTP servers or client hardware.
4026 vlan - When set to a value < 4095 the traffic over
4027 Ethernet is encapsulated/received over 802.1q
4030 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4031 Unsigned value, in milliseconds. If not set, the period will
4032 be either the default (28000), or a value based on
4033 CONFIG_NET_RETRY_COUNT, if defined. This value has
4034 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4036 The following image location variables contain the location of images
4037 used in booting. The "Image" column gives the role of the image and is
4038 not an environment variable name. The other columns are environment
4039 variable names. "File Name" gives the name of the file on a TFTP
4040 server, "RAM Address" gives the location in RAM the image will be
4041 loaded to, and "Flash Location" gives the image's address in NOR
4042 flash or offset in NAND flash.
4044 *Note* - these variables don't have to be defined for all boards, some
4045 boards currently use other variables for these purposes, and some
4046 boards use these variables for other purposes.
4048 Image File Name RAM Address Flash Location
4049 ----- --------- ----------- --------------
4050 u-boot u-boot u-boot_addr_r u-boot_addr
4051 Linux kernel bootfile kernel_addr_r kernel_addr
4052 device tree blob fdtfile fdt_addr_r fdt_addr
4053 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4055 The following environment variables may be used and automatically
4056 updated by the network boot commands ("bootp" and "rarpboot"),
4057 depending the information provided by your boot server:
4059 bootfile - see above
4060 dnsip - IP address of your Domain Name Server
4061 dnsip2 - IP address of your secondary Domain Name Server
4062 gatewayip - IP address of the Gateway (Router) to use
4063 hostname - Target hostname
4065 netmask - Subnet Mask
4066 rootpath - Pathname of the root filesystem on the NFS server
4067 serverip - see above
4070 There are two special Environment Variables:
4072 serial# - contains hardware identification information such
4073 as type string and/or serial number
4074 ethaddr - Ethernet address
4076 These variables can be set only once (usually during manufacturing of
4077 the board). U-Boot refuses to delete or overwrite these variables
4078 once they have been set once.
4081 Further special Environment Variables:
4083 ver - Contains the U-Boot version string as printed
4084 with the "version" command. This variable is
4085 readonly (see CONFIG_VERSION_VARIABLE).
4088 Please note that changes to some configuration parameters may take
4089 only effect after the next boot (yes, that's just like Windoze :-).
4092 Callback functions for environment variables:
4093 ---------------------------------------------
4095 For some environment variables, the behavior of u-boot needs to change
4096 when their values are changed. This functionality allows functions to
4097 be associated with arbitrary variables. On creation, overwrite, or
4098 deletion, the callback will provide the opportunity for some side
4099 effect to happen or for the change to be rejected.
4101 The callbacks are named and associated with a function using the
4102 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4104 These callbacks are associated with variables in one of two ways. The
4105 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4106 in the board configuration to a string that defines a list of
4107 associations. The list must be in the following format:
4109 entry = variable_name[:callback_name]
4112 If the callback name is not specified, then the callback is deleted.
4113 Spaces are also allowed anywhere in the list.
4115 Callbacks can also be associated by defining the ".callbacks" variable
4116 with the same list format above. Any association in ".callbacks" will
4117 override any association in the static list. You can define
4118 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4119 ".callbacks" environment variable in the default or embedded environment.
4121 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4122 regular expression. This allows multiple variables to be connected to
4123 the same callback without explicitly listing them all out.
4126 Command Line Parsing:
4127 =====================
4129 There are two different command line parsers available with U-Boot:
4130 the old "simple" one, and the much more powerful "hush" shell:
4132 Old, simple command line parser:
4133 --------------------------------
4135 - supports environment variables (through setenv / saveenv commands)
4136 - several commands on one line, separated by ';'
4137 - variable substitution using "... ${name} ..." syntax
4138 - special characters ('$', ';') can be escaped by prefixing with '\',
4140 setenv bootcmd bootm \${address}
4141 - You can also escape text by enclosing in single apostrophes, for example:
4142 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4147 - similar to Bourne shell, with control structures like
4148 if...then...else...fi, for...do...done; while...do...done,
4149 until...do...done, ...
4150 - supports environment ("global") variables (through setenv / saveenv
4151 commands) and local shell variables (through standard shell syntax
4152 "name=value"); only environment variables can be used with "run"
4158 (1) If a command line (or an environment variable executed by a "run"
4159 command) contains several commands separated by semicolon, and
4160 one of these commands fails, then the remaining commands will be
4163 (2) If you execute several variables with one call to run (i. e.
4164 calling run with a list of variables as arguments), any failing
4165 command will cause "run" to terminate, i. e. the remaining
4166 variables are not executed.
4168 Note for Redundant Ethernet Interfaces:
4169 =======================================
4171 Some boards come with redundant Ethernet interfaces; U-Boot supports
4172 such configurations and is capable of automatic selection of a
4173 "working" interface when needed. MAC assignment works as follows:
4175 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4176 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4177 "eth1addr" (=>eth1), "eth2addr", ...
4179 If the network interface stores some valid MAC address (for instance
4180 in SROM), this is used as default address if there is NO correspon-
4181 ding setting in the environment; if the corresponding environment
4182 variable is set, this overrides the settings in the card; that means:
4184 o If the SROM has a valid MAC address, and there is no address in the
4185 environment, the SROM's address is used.
4187 o If there is no valid address in the SROM, and a definition in the
4188 environment exists, then the value from the environment variable is
4191 o If both the SROM and the environment contain a MAC address, and
4192 both addresses are the same, this MAC address is used.
4194 o If both the SROM and the environment contain a MAC address, and the
4195 addresses differ, the value from the environment is used and a
4198 o If neither SROM nor the environment contain a MAC address, an error
4199 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4200 a random, locally-assigned MAC is used.
4202 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4203 will be programmed into hardware as part of the initialization process. This
4204 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4205 The naming convention is as follows:
4206 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4211 U-Boot is capable of booting (and performing other auxiliary operations on)
4212 images in two formats:
4214 New uImage format (FIT)
4215 -----------------------
4217 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4218 to Flattened Device Tree). It allows the use of images with multiple
4219 components (several kernels, ramdisks, etc.), with contents protected by
4220 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4226 Old image format is based on binary files which can be basically anything,
4227 preceded by a special header; see the definitions in include/image.h for
4228 details; basically, the header defines the following image properties:
4230 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4231 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4232 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4233 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4235 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4236 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4237 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4238 * Compression Type (uncompressed, gzip, bzip2)
4244 The header is marked by a special Magic Number, and both the header
4245 and the data portions of the image are secured against corruption by
4252 Although U-Boot should support any OS or standalone application
4253 easily, the main focus has always been on Linux during the design of
4256 U-Boot includes many features that so far have been part of some
4257 special "boot loader" code within the Linux kernel. Also, any
4258 "initrd" images to be used are no longer part of one big Linux image;
4259 instead, kernel and "initrd" are separate images. This implementation
4260 serves several purposes:
4262 - the same features can be used for other OS or standalone
4263 applications (for instance: using compressed images to reduce the
4264 Flash memory footprint)
4266 - it becomes much easier to port new Linux kernel versions because
4267 lots of low-level, hardware dependent stuff are done by U-Boot
4269 - the same Linux kernel image can now be used with different "initrd"
4270 images; of course this also means that different kernel images can
4271 be run with the same "initrd". This makes testing easier (you don't
4272 have to build a new "zImage.initrd" Linux image when you just
4273 change a file in your "initrd"). Also, a field-upgrade of the
4274 software is easier now.
4280 Porting Linux to U-Boot based systems:
4281 ---------------------------------------
4283 U-Boot cannot save you from doing all the necessary modifications to
4284 configure the Linux device drivers for use with your target hardware
4285 (no, we don't intend to provide a full virtual machine interface to
4288 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4290 Just make sure your machine specific header file (for instance
4291 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4292 Information structure as we define in include/asm-<arch>/u-boot.h,
4293 and make sure that your definition of IMAP_ADDR uses the same value
4294 as your U-Boot configuration in CONFIG_SYS_IMMR.
4296 Note that U-Boot now has a driver model, a unified model for drivers.
4297 If you are adding a new driver, plumb it into driver model. If there
4298 is no uclass available, you are encouraged to create one. See
4302 Configuring the Linux kernel:
4303 -----------------------------
4305 No specific requirements for U-Boot. Make sure you have some root
4306 device (initial ramdisk, NFS) for your target system.
4309 Building a Linux Image:
4310 -----------------------
4312 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4313 not used. If you use recent kernel source, a new build target
4314 "uImage" will exist which automatically builds an image usable by
4315 U-Boot. Most older kernels also have support for a "pImage" target,
4316 which was introduced for our predecessor project PPCBoot and uses a
4317 100% compatible format.
4321 make TQM850L_defconfig
4326 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4327 encapsulate a compressed Linux kernel image with header information,
4328 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4330 * build a standard "vmlinux" kernel image (in ELF binary format):
4332 * convert the kernel into a raw binary image:
4334 ${CROSS_COMPILE}-objcopy -O binary \
4335 -R .note -R .comment \
4336 -S vmlinux linux.bin
4338 * compress the binary image:
4342 * package compressed binary image for U-Boot:
4344 mkimage -A ppc -O linux -T kernel -C gzip \
4345 -a 0 -e 0 -n "Linux Kernel Image" \
4346 -d linux.bin.gz uImage
4349 The "mkimage" tool can also be used to create ramdisk images for use
4350 with U-Boot, either separated from the Linux kernel image, or
4351 combined into one file. "mkimage" encapsulates the images with a 64
4352 byte header containing information about target architecture,
4353 operating system, image type, compression method, entry points, time
4354 stamp, CRC32 checksums, etc.
4356 "mkimage" can be called in two ways: to verify existing images and
4357 print the header information, or to build new images.
4359 In the first form (with "-l" option) mkimage lists the information
4360 contained in the header of an existing U-Boot image; this includes
4361 checksum verification:
4363 tools/mkimage -l image
4364 -l ==> list image header information
4366 The second form (with "-d" option) is used to build a U-Boot image
4367 from a "data file" which is used as image payload:
4369 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4370 -n name -d data_file image
4371 -A ==> set architecture to 'arch'
4372 -O ==> set operating system to 'os'
4373 -T ==> set image type to 'type'
4374 -C ==> set compression type 'comp'
4375 -a ==> set load address to 'addr' (hex)
4376 -e ==> set entry point to 'ep' (hex)
4377 -n ==> set image name to 'name'
4378 -d ==> use image data from 'datafile'
4380 Right now, all Linux kernels for PowerPC systems use the same load
4381 address (0x00000000), but the entry point address depends on the
4384 - 2.2.x kernels have the entry point at 0x0000000C,
4385 - 2.3.x and later kernels have the entry point at 0x00000000.
4387 So a typical call to build a U-Boot image would read:
4389 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4390 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4391 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4392 > examples/uImage.TQM850L
4393 Image Name: 2.4.4 kernel for TQM850L
4394 Created: Wed Jul 19 02:34:59 2000
4395 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4396 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4397 Load Address: 0x00000000
4398 Entry Point: 0x00000000
4400 To verify the contents of the image (or check for corruption):
4402 -> tools/mkimage -l examples/uImage.TQM850L
4403 Image Name: 2.4.4 kernel for TQM850L
4404 Created: Wed Jul 19 02:34:59 2000
4405 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4406 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4407 Load Address: 0x00000000
4408 Entry Point: 0x00000000
4410 NOTE: for embedded systems where boot time is critical you can trade
4411 speed for memory and install an UNCOMPRESSED image instead: this
4412 needs more space in Flash, but boots much faster since it does not
4413 need to be uncompressed:
4415 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4416 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4417 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4418 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4419 > examples/uImage.TQM850L-uncompressed
4420 Image Name: 2.4.4 kernel for TQM850L
4421 Created: Wed Jul 19 02:34:59 2000
4422 Image Type: PowerPC Linux Kernel Image (uncompressed)
4423 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4424 Load Address: 0x00000000
4425 Entry Point: 0x00000000
4428 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4429 when your kernel is intended to use an initial ramdisk:
4431 -> tools/mkimage -n 'Simple Ramdisk Image' \
4432 > -A ppc -O linux -T ramdisk -C gzip \
4433 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4434 Image Name: Simple Ramdisk Image
4435 Created: Wed Jan 12 14:01:50 2000
4436 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4437 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4438 Load Address: 0x00000000
4439 Entry Point: 0x00000000
4441 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4442 option performs the converse operation of the mkimage's second form (the "-d"
4443 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4446 tools/dumpimage -i image -T type -p position data_file
4447 -i ==> extract from the 'image' a specific 'data_file'
4448 -T ==> set image type to 'type'
4449 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4452 Installing a Linux Image:
4453 -------------------------
4455 To downloading a U-Boot image over the serial (console) interface,
4456 you must convert the image to S-Record format:
4458 objcopy -I binary -O srec examples/image examples/image.srec
4460 The 'objcopy' does not understand the information in the U-Boot
4461 image header, so the resulting S-Record file will be relative to
4462 address 0x00000000. To load it to a given address, you need to
4463 specify the target address as 'offset' parameter with the 'loads'
4466 Example: install the image to address 0x40100000 (which on the
4467 TQM8xxL is in the first Flash bank):
4469 => erase 40100000 401FFFFF
4475 ## Ready for S-Record download ...
4476 ~>examples/image.srec
4477 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4479 15989 15990 15991 15992
4480 [file transfer complete]
4482 ## Start Addr = 0x00000000
4485 You can check the success of the download using the 'iminfo' command;
4486 this includes a checksum verification so you can be sure no data
4487 corruption happened:
4491 ## Checking Image at 40100000 ...
4492 Image Name: 2.2.13 for initrd on TQM850L
4493 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4494 Data Size: 335725 Bytes = 327 kB = 0 MB
4495 Load Address: 00000000
4496 Entry Point: 0000000c
4497 Verifying Checksum ... OK
4503 The "bootm" command is used to boot an application that is stored in
4504 memory (RAM or Flash). In case of a Linux kernel image, the contents
4505 of the "bootargs" environment variable is passed to the kernel as
4506 parameters. You can check and modify this variable using the
4507 "printenv" and "setenv" commands:
4510 => printenv bootargs
4511 bootargs=root=/dev/ram
4513 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4515 => printenv bootargs
4516 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4519 ## Booting Linux kernel at 40020000 ...
4520 Image Name: 2.2.13 for NFS on TQM850L
4521 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4522 Data Size: 381681 Bytes = 372 kB = 0 MB
4523 Load Address: 00000000
4524 Entry Point: 0000000c
4525 Verifying Checksum ... OK
4526 Uncompressing Kernel Image ... OK
4527 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
4528 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4529 time_init: decrementer frequency = 187500000/60
4530 Calibrating delay loop... 49.77 BogoMIPS
4531 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4534 If you want to boot a Linux kernel with initial RAM disk, you pass
4535 the memory addresses of both the kernel and the initrd image (PPBCOOT
4536 format!) to the "bootm" command:
4538 => imi 40100000 40200000
4540 ## Checking Image at 40100000 ...
4541 Image Name: 2.2.13 for initrd on TQM850L
4542 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4543 Data Size: 335725 Bytes = 327 kB = 0 MB
4544 Load Address: 00000000
4545 Entry Point: 0000000c
4546 Verifying Checksum ... OK
4548 ## Checking Image at 40200000 ...
4549 Image Name: Simple Ramdisk Image
4550 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4551 Data Size: 566530 Bytes = 553 kB = 0 MB
4552 Load Address: 00000000
4553 Entry Point: 00000000
4554 Verifying Checksum ... OK
4556 => bootm 40100000 40200000
4557 ## Booting Linux kernel at 40100000 ...
4558 Image Name: 2.2.13 for initrd on TQM850L
4559 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4560 Data Size: 335725 Bytes = 327 kB = 0 MB
4561 Load Address: 00000000
4562 Entry Point: 0000000c
4563 Verifying Checksum ... OK
4564 Uncompressing Kernel Image ... OK
4565 ## Loading RAMDisk Image at 40200000 ...
4566 Image Name: Simple Ramdisk Image
4567 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4568 Data Size: 566530 Bytes = 553 kB = 0 MB
4569 Load Address: 00000000
4570 Entry Point: 00000000
4571 Verifying Checksum ... OK
4572 Loading Ramdisk ... OK
4573 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
4574 Boot arguments: root=/dev/ram
4575 time_init: decrementer frequency = 187500000/60
4576 Calibrating delay loop... 49.77 BogoMIPS
4578 RAMDISK: Compressed image found at block 0
4579 VFS: Mounted root (ext2 filesystem).
4583 Boot Linux and pass a flat device tree:
4586 First, U-Boot must be compiled with the appropriate defines. See the section
4587 titled "Linux Kernel Interface" above for a more in depth explanation. The
4588 following is an example of how to start a kernel and pass an updated
4594 oft=oftrees/mpc8540ads.dtb
4595 => tftp $oftaddr $oft
4596 Speed: 1000, full duplex
4598 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4599 Filename 'oftrees/mpc8540ads.dtb'.
4600 Load address: 0x300000
4603 Bytes transferred = 4106 (100a hex)
4604 => tftp $loadaddr $bootfile
4605 Speed: 1000, full duplex
4607 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4609 Load address: 0x200000
4610 Loading:############
4612 Bytes transferred = 1029407 (fb51f hex)
4617 => bootm $loadaddr - $oftaddr
4618 ## Booting image at 00200000 ...
4619 Image Name: Linux-2.6.17-dirty
4620 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4621 Data Size: 1029343 Bytes = 1005.2 kB
4622 Load Address: 00000000
4623 Entry Point: 00000000
4624 Verifying Checksum ... OK
4625 Uncompressing Kernel Image ... OK
4626 Booting using flat device tree at 0x300000
4627 Using MPC85xx ADS machine description
4628 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4632 More About U-Boot Image Types:
4633 ------------------------------
4635 U-Boot supports the following image types:
4637 "Standalone Programs" are directly runnable in the environment
4638 provided by U-Boot; it is expected that (if they behave
4639 well) you can continue to work in U-Boot after return from
4640 the Standalone Program.
4641 "OS Kernel Images" are usually images of some Embedded OS which
4642 will take over control completely. Usually these programs
4643 will install their own set of exception handlers, device
4644 drivers, set up the MMU, etc. - this means, that you cannot
4645 expect to re-enter U-Boot except by resetting the CPU.
4646 "RAMDisk Images" are more or less just data blocks, and their
4647 parameters (address, size) are passed to an OS kernel that is
4649 "Multi-File Images" contain several images, typically an OS
4650 (Linux) kernel image and one or more data images like
4651 RAMDisks. This construct is useful for instance when you want
4652 to boot over the network using BOOTP etc., where the boot
4653 server provides just a single image file, but you want to get
4654 for instance an OS kernel and a RAMDisk image.
4656 "Multi-File Images" start with a list of image sizes, each
4657 image size (in bytes) specified by an "uint32_t" in network
4658 byte order. This list is terminated by an "(uint32_t)0".
4659 Immediately after the terminating 0 follow the images, one by
4660 one, all aligned on "uint32_t" boundaries (size rounded up to
4661 a multiple of 4 bytes).
4663 "Firmware Images" are binary images containing firmware (like
4664 U-Boot or FPGA images) which usually will be programmed to
4667 "Script files" are command sequences that will be executed by
4668 U-Boot's command interpreter; this feature is especially
4669 useful when you configure U-Boot to use a real shell (hush)
4670 as command interpreter.
4672 Booting the Linux zImage:
4673 -------------------------
4675 On some platforms, it's possible to boot Linux zImage. This is done
4676 using the "bootz" command. The syntax of "bootz" command is the same
4677 as the syntax of "bootm" command.
4679 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4680 kernel with raw initrd images. The syntax is slightly different, the
4681 address of the initrd must be augmented by it's size, in the following
4682 format: "<initrd addres>:<initrd size>".
4688 One of the features of U-Boot is that you can dynamically load and
4689 run "standalone" applications, which can use some resources of
4690 U-Boot like console I/O functions or interrupt services.
4692 Two simple examples are included with the sources:
4697 'examples/hello_world.c' contains a small "Hello World" Demo
4698 application; it is automatically compiled when you build U-Boot.
4699 It's configured to run at address 0x00040004, so you can play with it
4703 ## Ready for S-Record download ...
4704 ~>examples/hello_world.srec
4705 1 2 3 4 5 6 7 8 9 10 11 ...
4706 [file transfer complete]
4708 ## Start Addr = 0x00040004
4710 => go 40004 Hello World! This is a test.
4711 ## Starting application at 0x00040004 ...
4722 Hit any key to exit ...
4724 ## Application terminated, rc = 0x0
4726 Another example, which demonstrates how to register a CPM interrupt
4727 handler with the U-Boot code, can be found in 'examples/timer.c'.
4728 Here, a CPM timer is set up to generate an interrupt every second.
4729 The interrupt service routine is trivial, just printing a '.'
4730 character, but this is just a demo program. The application can be
4731 controlled by the following keys:
4733 ? - print current values og the CPM Timer registers
4734 b - enable interrupts and start timer
4735 e - stop timer and disable interrupts
4736 q - quit application
4739 ## Ready for S-Record download ...
4740 ~>examples/timer.srec
4741 1 2 3 4 5 6 7 8 9 10 11 ...
4742 [file transfer complete]
4744 ## Start Addr = 0x00040004
4747 ## Starting application at 0x00040004 ...
4750 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4753 [q, b, e, ?] Set interval 1000000 us
4756 [q, b, e, ?] ........
4757 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4760 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4763 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4766 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4768 [q, b, e, ?] ...Stopping timer
4770 [q, b, e, ?] ## Application terminated, rc = 0x0
4776 Over time, many people have reported problems when trying to use the
4777 "minicom" terminal emulation program for serial download. I (wd)
4778 consider minicom to be broken, and recommend not to use it. Under
4779 Unix, I recommend to use C-Kermit for general purpose use (and
4780 especially for kermit binary protocol download ("loadb" command), and
4781 use "cu" for S-Record download ("loads" command). See
4782 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4783 for help with kermit.
4786 Nevertheless, if you absolutely want to use it try adding this
4787 configuration to your "File transfer protocols" section:
4789 Name Program Name U/D FullScr IO-Red. Multi
4790 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4791 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4797 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4798 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4800 Building requires a cross environment; it is known to work on
4801 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4802 need gmake since the Makefiles are not compatible with BSD make).
4803 Note that the cross-powerpc package does not install include files;
4804 attempting to build U-Boot will fail because <machine/ansi.h> is
4805 missing. This file has to be installed and patched manually:
4807 # cd /usr/pkg/cross/powerpc-netbsd/include
4809 # ln -s powerpc machine
4810 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4811 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4813 Native builds *don't* work due to incompatibilities between native
4814 and U-Boot include files.
4816 Booting assumes that (the first part of) the image booted is a
4817 stage-2 loader which in turn loads and then invokes the kernel
4818 proper. Loader sources will eventually appear in the NetBSD source
4819 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4820 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4823 Implementation Internals:
4824 =========================
4826 The following is not intended to be a complete description of every
4827 implementation detail. However, it should help to understand the
4828 inner workings of U-Boot and make it easier to port it to custom
4832 Initial Stack, Global Data:
4833 ---------------------------
4835 The implementation of U-Boot is complicated by the fact that U-Boot
4836 starts running out of ROM (flash memory), usually without access to
4837 system RAM (because the memory controller is not initialized yet).
4838 This means that we don't have writable Data or BSS segments, and BSS
4839 is not initialized as zero. To be able to get a C environment working
4840 at all, we have to allocate at least a minimal stack. Implementation
4841 options for this are defined and restricted by the CPU used: Some CPU
4842 models provide on-chip memory (like the IMMR area on MPC8xx and
4843 MPC826x processors), on others (parts of) the data cache can be
4844 locked as (mis-) used as memory, etc.
4846 Chris Hallinan posted a good summary of these issues to the
4847 U-Boot mailing list:
4849 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4850 From: "Chris Hallinan" <clh@net1plus.com>
4851 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4854 Correct me if I'm wrong, folks, but the way I understand it
4855 is this: Using DCACHE as initial RAM for Stack, etc, does not
4856 require any physical RAM backing up the cache. The cleverness
4857 is that the cache is being used as a temporary supply of
4858 necessary storage before the SDRAM controller is setup. It's
4859 beyond the scope of this list to explain the details, but you
4860 can see how this works by studying the cache architecture and
4861 operation in the architecture and processor-specific manuals.
4863 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4864 is another option for the system designer to use as an
4865 initial stack/RAM area prior to SDRAM being available. Either
4866 option should work for you. Using CS 4 should be fine if your
4867 board designers haven't used it for something that would
4868 cause you grief during the initial boot! It is frequently not
4871 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4872 with your processor/board/system design. The default value
4873 you will find in any recent u-boot distribution in
4874 walnut.h should work for you. I'd set it to a value larger
4875 than your SDRAM module. If you have a 64MB SDRAM module, set
4876 it above 400_0000. Just make sure your board has no resources
4877 that are supposed to respond to that address! That code in
4878 start.S has been around a while and should work as is when
4879 you get the config right.
4884 It is essential to remember this, since it has some impact on the C
4885 code for the initialization procedures:
4887 * Initialized global data (data segment) is read-only. Do not attempt
4890 * Do not use any uninitialized global data (or implicitly initialized
4891 as zero data - BSS segment) at all - this is undefined, initiali-
4892 zation is performed later (when relocating to RAM).
4894 * Stack space is very limited. Avoid big data buffers or things like
4897 Having only the stack as writable memory limits means we cannot use
4898 normal global data to share information between the code. But it
4899 turned out that the implementation of U-Boot can be greatly
4900 simplified by making a global data structure (gd_t) available to all
4901 functions. We could pass a pointer to this data as argument to _all_
4902 functions, but this would bloat the code. Instead we use a feature of
4903 the GCC compiler (Global Register Variables) to share the data: we
4904 place a pointer (gd) to the global data into a register which we
4905 reserve for this purpose.
4907 When choosing a register for such a purpose we are restricted by the
4908 relevant (E)ABI specifications for the current architecture, and by
4909 GCC's implementation.
4911 For PowerPC, the following registers have specific use:
4913 R2: reserved for system use
4914 R3-R4: parameter passing and return values
4915 R5-R10: parameter passing
4916 R13: small data area pointer
4920 (U-Boot also uses R12 as internal GOT pointer. r12
4921 is a volatile register so r12 needs to be reset when
4922 going back and forth between asm and C)
4924 ==> U-Boot will use R2 to hold a pointer to the global data
4926 Note: on PPC, we could use a static initializer (since the
4927 address of the global data structure is known at compile time),
4928 but it turned out that reserving a register results in somewhat
4929 smaller code - although the code savings are not that big (on
4930 average for all boards 752 bytes for the whole U-Boot image,
4931 624 text + 127 data).
4933 On ARM, the following registers are used:
4935 R0: function argument word/integer result
4936 R1-R3: function argument word
4937 R9: platform specific
4938 R10: stack limit (used only if stack checking is enabled)
4939 R11: argument (frame) pointer
4940 R12: temporary workspace
4943 R15: program counter
4945 ==> U-Boot will use R9 to hold a pointer to the global data
4947 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
4949 On Nios II, the ABI is documented here:
4950 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4952 ==> U-Boot will use gp to hold a pointer to the global data
4954 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4955 to access small data sections, so gp is free.
4957 On NDS32, the following registers are used:
4959 R0-R1: argument/return
4961 R15: temporary register for assembler
4962 R16: trampoline register
4963 R28: frame pointer (FP)
4964 R29: global pointer (GP)
4965 R30: link register (LP)
4966 R31: stack pointer (SP)
4967 PC: program counter (PC)
4969 ==> U-Boot will use R10 to hold a pointer to the global data
4971 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4972 or current versions of GCC may "optimize" the code too much.
4977 U-Boot runs in system state and uses physical addresses, i.e. the
4978 MMU is not used either for address mapping nor for memory protection.
4980 The available memory is mapped to fixed addresses using the memory
4981 controller. In this process, a contiguous block is formed for each
4982 memory type (Flash, SDRAM, SRAM), even when it consists of several
4983 physical memory banks.
4985 U-Boot is installed in the first 128 kB of the first Flash bank (on
4986 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4987 booting and sizing and initializing DRAM, the code relocates itself
4988 to the upper end of DRAM. Immediately below the U-Boot code some
4989 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4990 configuration setting]. Below that, a structure with global Board
4991 Info data is placed, followed by the stack (growing downward).
4993 Additionally, some exception handler code is copied to the low 8 kB
4994 of DRAM (0x00000000 ... 0x00001FFF).
4996 So a typical memory configuration with 16 MB of DRAM could look like
4999 0x0000 0000 Exception Vector code
5002 0x0000 2000 Free for Application Use
5008 0x00FB FF20 Monitor Stack (Growing downward)
5009 0x00FB FFAC Board Info Data and permanent copy of global data
5010 0x00FC 0000 Malloc Arena
5013 0x00FE 0000 RAM Copy of Monitor Code
5014 ... eventually: LCD or video framebuffer
5015 ... eventually: pRAM (Protected RAM - unchanged by reset)
5016 0x00FF FFFF [End of RAM]
5019 System Initialization:
5020 ----------------------
5022 In the reset configuration, U-Boot starts at the reset entry point
5023 (on most PowerPC systems at address 0x00000100). Because of the reset
5024 configuration for CS0# this is a mirror of the on board Flash memory.
5025 To be able to re-map memory U-Boot then jumps to its link address.
5026 To be able to implement the initialization code in C, a (small!)
5027 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5028 which provide such a feature like), or in a locked part of the data
5029 cache. After that, U-Boot initializes the CPU core, the caches and
5032 Next, all (potentially) available memory banks are mapped using a
5033 preliminary mapping. For example, we put them on 512 MB boundaries
5034 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5035 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5036 programmed for SDRAM access. Using the temporary configuration, a
5037 simple memory test is run that determines the size of the SDRAM
5040 When there is more than one SDRAM bank, and the banks are of
5041 different size, the largest is mapped first. For equal size, the first
5042 bank (CS2#) is mapped first. The first mapping is always for address
5043 0x00000000, with any additional banks following immediately to create
5044 contiguous memory starting from 0.
5046 Then, the monitor installs itself at the upper end of the SDRAM area
5047 and allocates memory for use by malloc() and for the global Board
5048 Info data; also, the exception vector code is copied to the low RAM
5049 pages, and the final stack is set up.
5051 Only after this relocation will you have a "normal" C environment;
5052 until that you are restricted in several ways, mostly because you are
5053 running from ROM, and because the code will have to be relocated to a
5057 U-Boot Porting Guide:
5058 ----------------------
5060 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5064 int main(int argc, char *argv[])
5066 sighandler_t no_more_time;
5068 signal(SIGALRM, no_more_time);
5069 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5071 if (available_money > available_manpower) {
5072 Pay consultant to port U-Boot;
5076 Download latest U-Boot source;
5078 Subscribe to u-boot mailing list;
5081 email("Hi, I am new to U-Boot, how do I get started?");
5084 Read the README file in the top level directory;
5085 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5086 Read applicable doc/*.README;
5087 Read the source, Luke;
5088 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5091 if (available_money > toLocalCurrency ($2500))
5094 Add a lot of aggravation and time;
5096 if (a similar board exists) { /* hopefully... */
5097 cp -a board/<similar> board/<myboard>
5098 cp include/configs/<similar>.h include/configs/<myboard>.h
5100 Create your own board support subdirectory;
5101 Create your own board include/configs/<myboard>.h file;
5103 Edit new board/<myboard> files
5104 Edit new include/configs/<myboard>.h
5109 Add / modify source code;
5113 email("Hi, I am having problems...");
5115 Send patch file to the U-Boot email list;
5116 if (reasonable critiques)
5117 Incorporate improvements from email list code review;
5119 Defend code as written;
5125 void no_more_time (int sig)
5134 All contributions to U-Boot should conform to the Linux kernel
5135 coding style; see the file "Documentation/CodingStyle" and the script
5136 "scripts/Lindent" in your Linux kernel source directory.
5138 Source files originating from a different project (for example the
5139 MTD subsystem) are generally exempt from these guidelines and are not
5140 reformatted to ease subsequent migration to newer versions of those
5143 Please note that U-Boot is implemented in C (and to some small parts in
5144 Assembler); no C++ is used, so please do not use C++ style comments (//)
5147 Please also stick to the following formatting rules:
5148 - remove any trailing white space
5149 - use TAB characters for indentation and vertical alignment, not spaces
5150 - make sure NOT to use DOS '\r\n' line feeds
5151 - do not add more than 2 consecutive empty lines to source files
5152 - do not add trailing empty lines to source files
5154 Submissions which do not conform to the standards may be returned
5155 with a request to reformat the changes.
5161 Since the number of patches for U-Boot is growing, we need to
5162 establish some rules. Submissions which do not conform to these rules
5163 may be rejected, even when they contain important and valuable stuff.
5165 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5167 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5168 see http://lists.denx.de/mailman/listinfo/u-boot
5170 When you send a patch, please include the following information with
5173 * For bug fixes: a description of the bug and how your patch fixes
5174 this bug. Please try to include a way of demonstrating that the
5175 patch actually fixes something.
5177 * For new features: a description of the feature and your
5180 * A CHANGELOG entry as plaintext (separate from the patch)
5182 * For major contributions, add a MAINTAINERS file with your
5183 information and associated file and directory references.
5185 * When you add support for a new board, don't forget to add a
5186 maintainer e-mail address to the boards.cfg file, too.
5188 * If your patch adds new configuration options, don't forget to
5189 document these in the README file.
5191 * The patch itself. If you are using git (which is *strongly*
5192 recommended) you can easily generate the patch using the
5193 "git format-patch". If you then use "git send-email" to send it to
5194 the U-Boot mailing list, you will avoid most of the common problems
5195 with some other mail clients.
5197 If you cannot use git, use "diff -purN OLD NEW". If your version of
5198 diff does not support these options, then get the latest version of
5201 The current directory when running this command shall be the parent
5202 directory of the U-Boot source tree (i. e. please make sure that
5203 your patch includes sufficient directory information for the
5206 We prefer patches as plain text. MIME attachments are discouraged,
5207 and compressed attachments must not be used.
5209 * If one logical set of modifications affects or creates several
5210 files, all these changes shall be submitted in a SINGLE patch file.
5212 * Changesets that contain different, unrelated modifications shall be
5213 submitted as SEPARATE patches, one patch per changeset.
5218 * Before sending the patch, run the buildman script on your patched
5219 source tree and make sure that no errors or warnings are reported
5220 for any of the boards.
5222 * Keep your modifications to the necessary minimum: A patch
5223 containing several unrelated changes or arbitrary reformats will be
5224 returned with a request to re-formatting / split it.
5226 * If you modify existing code, make sure that your new code does not
5227 add to the memory footprint of the code ;-) Small is beautiful!
5228 When adding new features, these should compile conditionally only
5229 (using #ifdef), and the resulting code with the new feature
5230 disabled must not need more memory than the old code without your
5233 * Remember that there is a size limit of 100 kB per message on the
5234 u-boot mailing list. Bigger patches will be moderated. If they are
5235 reasonable and not too big, they will be acknowledged. But patches
5236 bigger than the size limit should be avoided.