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.
315 - ARM Platform Bus Type(CCI):
316 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
317 provides full cache coherency between two clusters of multi-core
318 CPUs and I/O coherency for devices and I/O masters
320 CONFIG_SYS_FSL_HAS_CCI400
322 Defined For SoC that has cache coherent interconnect
325 CONFIG_SYS_FSL_HAS_CCN504
327 Defined for SoC that has cache coherent interconnect CCN-504
329 The following options need to be configured:
331 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
333 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
335 - Marvell Family Member
336 CONFIG_SYS_MVFS - define it if you want to enable
337 multiple fs option at one time
338 for marvell soc family
343 Specifies that the core is a 64-bit PowerPC implementation (implements
344 the "64" category of the Power ISA). This is necessary for ePAPR
345 compliance, among other possible reasons.
347 CONFIG_SYS_FSL_TBCLK_DIV
349 Defines the core time base clock divider ratio compared to the
350 system clock. On most PQ3 devices this is 8, on newer QorIQ
351 devices it can be 16 or 32. The ratio varies from SoC to Soc.
353 CONFIG_SYS_FSL_PCIE_COMPAT
355 Defines the string to utilize when trying to match PCIe device
356 tree nodes for the given platform.
358 CONFIG_SYS_FSL_ERRATUM_A004510
360 Enables a workaround for erratum A004510. If set,
361 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
362 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
364 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
365 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
367 Defines one or two SoC revisions (low 8 bits of SVR)
368 for which the A004510 workaround should be applied.
370 The rest of SVR is either not relevant to the decision
371 of whether the erratum is present (e.g. p2040 versus
372 p2041) or is implied by the build target, which controls
373 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
375 See Freescale App Note 4493 for more information about
378 CONFIG_A003399_NOR_WORKAROUND
379 Enables a workaround for IFC erratum A003399. It is only
380 required during NOR boot.
382 CONFIG_A008044_WORKAROUND
383 Enables a workaround for T1040/T1042 erratum A008044. It is only
384 required during NAND boot and valid for Rev 1.0 SoC revision
386 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
388 This is the value to write into CCSR offset 0x18600
389 according to the A004510 workaround.
391 CONFIG_SYS_FSL_DSP_DDR_ADDR
392 This value denotes start offset of DDR memory which is
393 connected exclusively to the DSP cores.
395 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
396 This value denotes start offset of M2 memory
397 which is directly connected to the DSP core.
399 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
400 This value denotes start offset of M3 memory which is directly
401 connected to the DSP core.
403 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
404 This value denotes start offset of DSP CCSR space.
406 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
407 Single Source Clock is clocking mode present in some of FSL SoC's.
408 In this mode, a single differential clock is used to supply
409 clocks to the sysclock, ddrclock and usbclock.
411 CONFIG_SYS_CPC_REINIT_F
412 This CONFIG is defined when the CPC is configured as SRAM at the
413 time of U-Boot entry and is required to be re-initialized.
416 Indicates this SoC supports deep sleep feature. If deep sleep is
417 supported, core will start to execute uboot when wakes up.
419 - Generic CPU options:
420 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
422 Defines the endianess of the CPU. Implementation of those
423 values is arch specific.
426 Freescale DDR driver in use. This type of DDR controller is
427 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
430 CONFIG_SYS_FSL_DDR_ADDR
431 Freescale DDR memory-mapped register base.
433 CONFIG_SYS_FSL_DDR_EMU
434 Specify emulator support for DDR. Some DDR features such as
435 deskew training are not available.
437 CONFIG_SYS_FSL_DDRC_GEN1
438 Freescale DDR1 controller.
440 CONFIG_SYS_FSL_DDRC_GEN2
441 Freescale DDR2 controller.
443 CONFIG_SYS_FSL_DDRC_GEN3
444 Freescale DDR3 controller.
446 CONFIG_SYS_FSL_DDRC_GEN4
447 Freescale DDR4 controller.
449 CONFIG_SYS_FSL_DDRC_ARM_GEN3
450 Freescale DDR3 controller for ARM-based SoCs.
453 Board config to use DDR1. It can be enabled for SoCs with
454 Freescale DDR1 or DDR2 controllers, depending on the board
458 Board config to use DDR2. It can be enabled for SoCs with
459 Freescale DDR2 or DDR3 controllers, depending on the board
463 Board config to use DDR3. It can be enabled for SoCs with
464 Freescale DDR3 or DDR3L controllers.
467 Board config to use DDR3L. It can be enabled for SoCs with
471 Board config to use DDR4. It can be enabled for SoCs with
474 CONFIG_SYS_FSL_IFC_BE
475 Defines the IFC controller register space as Big Endian
477 CONFIG_SYS_FSL_IFC_LE
478 Defines the IFC controller register space as Little Endian
480 CONFIG_SYS_FSL_IFC_CLK_DIV
481 Defines divider of platform clock(clock input to IFC controller).
483 CONFIG_SYS_FSL_LBC_CLK_DIV
484 Defines divider of platform clock(clock input to eLBC controller).
486 CONFIG_SYS_FSL_PBL_PBI
487 It enables addition of RCW (Power on reset configuration) in built image.
488 Please refer doc/README.pblimage for more details
490 CONFIG_SYS_FSL_PBL_RCW
491 It adds PBI(pre-boot instructions) commands in u-boot build image.
492 PBI commands can be used to configure SoC before it starts the execution.
493 Please refer doc/README.pblimage for more details
496 It adds a target to create boot binary having SPL binary in PBI format
497 concatenated with u-boot binary.
499 CONFIG_SYS_FSL_DDR_BE
500 Defines the DDR controller register space as Big Endian
502 CONFIG_SYS_FSL_DDR_LE
503 Defines the DDR controller register space as Little Endian
505 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
506 Physical address from the view of DDR controllers. It is the
507 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
508 it could be different for ARM SoCs.
510 CONFIG_SYS_FSL_DDR_INTLV_256B
511 DDR controller interleaving on 256-byte. This is a special
512 interleaving mode, handled by Dickens for Freescale layerscape
515 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
516 Number of controllers used as main memory.
518 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
519 Number of controllers used for other than main memory.
521 CONFIG_SYS_FSL_HAS_DP_DDR
522 Defines the SoC has DP-DDR used for DPAA.
524 CONFIG_SYS_FSL_SEC_BE
525 Defines the SEC controller register space as Big Endian
527 CONFIG_SYS_FSL_SEC_LE
528 Defines the SEC controller register space as Little Endian
531 CONFIG_SYS_INIT_SP_OFFSET
533 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
534 pointer. This is needed for the temporary stack before
537 CONFIG_SYS_MIPS_CACHE_MODE
539 Cache operation mode for the MIPS CPU.
540 See also arch/mips/include/asm/mipsregs.h.
542 CONF_CM_CACHABLE_NO_WA
545 CONF_CM_CACHABLE_NONCOHERENT
549 CONF_CM_CACHABLE_ACCELERATED
551 CONFIG_SYS_XWAY_EBU_BOOTCFG
553 Special option for Lantiq XWAY SoCs for booting from NOR flash.
554 See also arch/mips/cpu/mips32/start.S.
556 CONFIG_XWAY_SWAP_BYTES
558 Enable compilation of tools/xway-swap-bytes needed for Lantiq
559 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
560 be swapped if a flash programmer is used.
563 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
565 Select high exception vectors of the ARM core, e.g., do not
566 clear the V bit of the c1 register of CP15.
569 Generic timer clock source frequency.
571 COUNTER_FREQUENCY_REAL
572 Generic timer clock source frequency if the real clock is
573 different from COUNTER_FREQUENCY, and can only be determined
577 CONFIG_TEGRA_SUPPORT_NON_SECURE
579 Support executing U-Boot in non-secure (NS) mode. Certain
580 impossible actions will be skipped if the CPU is in NS mode,
581 such as ARM architectural timer initialization.
583 - Linux Kernel Interface:
586 U-Boot stores all clock information in Hz
587 internally. For binary compatibility with older Linux
588 kernels (which expect the clocks passed in the
589 bd_info data to be in MHz) the environment variable
590 "clocks_in_mhz" can be defined so that U-Boot
591 converts clock data to MHZ before passing it to the
593 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
594 "clocks_in_mhz=1" is automatically included in the
597 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
599 When transferring memsize parameter to Linux, some versions
600 expect it to be in bytes, others in MB.
601 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
605 New kernel versions are expecting firmware settings to be
606 passed using flattened device trees (based on open firmware
610 * New libfdt-based support
611 * Adds the "fdt" command
612 * The bootm command automatically updates the fdt
614 OF_TBCLK - The timebase frequency.
615 OF_STDOUT_PATH - The path to the console device
617 boards with QUICC Engines require OF_QE to set UCC MAC
620 CONFIG_OF_BOARD_SETUP
622 Board code has addition modification that it wants to make
623 to the flat device tree before handing it off to the kernel
625 CONFIG_OF_SYSTEM_SETUP
627 Other code has addition modification that it wants to make
628 to the flat device tree before handing it off to the kernel.
629 This causes ft_system_setup() to be called before booting
634 U-Boot can detect if an IDE device is present or not.
635 If not, and this new config option is activated, U-Boot
636 removes the ATA node from the DTS before booting Linux,
637 so the Linux IDE driver does not probe the device and
638 crash. This is needed for buggy hardware (uc101) where
639 no pull down resistor is connected to the signal IDE5V_DD7.
641 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
643 This setting is mandatory for all boards that have only one
644 machine type and must be used to specify the machine type
645 number as it appears in the ARM machine registry
646 (see http://www.arm.linux.org.uk/developer/machines/).
647 Only boards that have multiple machine types supported
648 in a single configuration file and the machine type is
649 runtime discoverable, do not have to use this setting.
651 - vxWorks boot parameters:
653 bootvx constructs a valid bootline using the following
654 environments variables: bootdev, bootfile, ipaddr, netmask,
655 serverip, gatewayip, hostname, othbootargs.
656 It loads the vxWorks image pointed bootfile.
658 Note: If a "bootargs" environment is defined, it will overwride
659 the defaults discussed just above.
661 - Cache Configuration:
662 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
663 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
664 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
666 - Cache Configuration for ARM:
667 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
669 CONFIG_SYS_PL310_BASE - Physical base address of PL310
670 controller register space
675 Define this if you want support for Amba PrimeCell PL010 UARTs.
679 Define this if you want support for Amba PrimeCell PL011 UARTs.
683 If you have Amba PrimeCell PL011 UARTs, set this variable to
684 the clock speed of the UARTs.
688 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
689 define this to a list of base addresses for each (supported)
690 port. See e.g. include/configs/versatile.h
692 CONFIG_SERIAL_HW_FLOW_CONTROL
694 Define this variable to enable hw flow control in serial driver.
695 Current user of this option is drivers/serial/nsl16550.c driver
698 CONFIG_BAUDRATE - in bps
699 Select one of the baudrates listed in
700 CONFIG_SYS_BAUDRATE_TABLE, see below.
704 Only needed when CONFIG_BOOTDELAY is enabled;
705 define a command string that is automatically executed
706 when no character is read on the console interface
707 within "Boot Delay" after reset.
709 CONFIG_RAMBOOT and CONFIG_NFSBOOT
710 The value of these goes into the environment as
711 "ramboot" and "nfsboot" respectively, and can be used
712 as a convenience, when switching between booting from
716 CONFIG_BOOTCOUNT_LIMIT
717 Implements a mechanism for detecting a repeating reboot
719 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
722 If no softreset save registers are found on the hardware
723 "bootcount" is stored in the environment. To prevent a
724 saveenv on all reboots, the environment variable
725 "upgrade_available" is used. If "upgrade_available" is
726 0, "bootcount" is always 0, if "upgrade_available" is
727 1 "bootcount" is incremented in the environment.
728 So the Userspace Applikation must set the "upgrade_available"
729 and "bootcount" variable to 0, if a boot was successfully.
734 When this option is #defined, the existence of the
735 environment variable "preboot" will be checked
736 immediately before starting the CONFIG_BOOTDELAY
737 countdown and/or running the auto-boot command resp.
738 entering interactive mode.
740 This feature is especially useful when "preboot" is
741 automatically generated or modified. For an example
742 see the LWMON board specific code: here "preboot" is
743 modified when the user holds down a certain
744 combination of keys on the (special) keyboard when
747 - Serial Download Echo Mode:
749 If defined to 1, all characters received during a
750 serial download (using the "loads" command) are
751 echoed back. This might be needed by some terminal
752 emulations (like "cu"), but may as well just take
753 time on others. This setting #define's the initial
754 value of the "loads_echo" environment variable.
756 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
758 Select one of the baudrates listed in
759 CONFIG_SYS_BAUDRATE_TABLE, see below.
761 - Removal of commands
762 If no commands are needed to boot, you can disable
763 CONFIG_CMDLINE to remove them. In this case, the command line
764 will not be available, and when U-Boot wants to execute the
765 boot command (on start-up) it will call board_run_command()
766 instead. This can reduce image size significantly for very
767 simple boot procedures.
769 - Regular expression support:
771 If this variable is defined, U-Boot is linked against
772 the SLRE (Super Light Regular Expression) library,
773 which adds regex support to some commands, as for
774 example "env grep" and "setexpr".
778 If this variable is defined, U-Boot will use a device tree
779 to configure its devices, instead of relying on statically
780 compiled #defines in the board file. This option is
781 experimental and only available on a few boards. The device
782 tree is available in the global data as gd->fdt_blob.
784 U-Boot needs to get its device tree from somewhere. This can
785 be done using one of the three options below:
788 If this variable is defined, U-Boot will embed a device tree
789 binary in its image. This device tree file should be in the
790 board directory and called <soc>-<board>.dts. The binary file
791 is then picked up in board_init_f() and made available through
792 the global data structure as gd->fdt_blob.
795 If this variable is defined, U-Boot will build a device tree
796 binary. It will be called u-boot.dtb. Architecture-specific
797 code will locate it at run-time. Generally this works by:
799 cat u-boot.bin u-boot.dtb >image.bin
801 and in fact, U-Boot does this for you, creating a file called
802 u-boot-dtb.bin which is useful in the common case. You can
803 still use the individual files if you need something more
807 If this variable is defined, U-Boot will use the device tree
808 provided by the board at runtime instead of embedding one with
809 the image. Only boards defining board_fdt_blob_setup() support
810 this option (see include/fdtdec.h file).
814 If this variable is defined, it enables watchdog
815 support for the SoC. There must be support in the SoC
816 specific code for a watchdog. For the 8xx
817 CPUs, the SIU Watchdog feature is enabled in the SYPCR
818 register. When supported for a specific SoC is
819 available, then no further board specific code should
823 When using a watchdog circuitry external to the used
824 SoC, then define this variable and provide board
825 specific code for the "hw_watchdog_reset" function.
827 CONFIG_AT91_HW_WDT_TIMEOUT
828 specify the timeout in seconds. default 2 seconds.
831 CONFIG_VERSION_VARIABLE
832 If this variable is defined, an environment variable
833 named "ver" is created by U-Boot showing the U-Boot
834 version as printed by the "version" command.
835 Any change to this variable will be reverted at the
840 When CONFIG_CMD_DATE is selected, the type of the RTC
841 has to be selected, too. Define exactly one of the
844 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
845 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
846 CONFIG_RTC_MC146818 - use MC146818 RTC
847 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
848 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
849 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
850 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
851 CONFIG_RTC_DS164x - use Dallas DS164x RTC
852 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
853 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
854 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
855 CONFIG_SYS_RV3029_TCR - enable trickle charger on
858 Note that if the RTC uses I2C, then the I2C interface
859 must also be configured. See I2C Support, below.
862 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
864 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
865 chip-ngpio pairs that tell the PCA953X driver the number of
866 pins supported by a particular chip.
868 Note that if the GPIO device uses I2C, then the I2C interface
869 must also be configured. See I2C Support, below.
872 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
873 accesses and can checksum them or write a list of them out
874 to memory. See the 'iotrace' command for details. This is
875 useful for testing device drivers since it can confirm that
876 the driver behaves the same way before and after a code
877 change. Currently this is supported on sandbox and arm. To
878 add support for your architecture, add '#include <iotrace.h>'
879 to the bottom of arch/<arch>/include/asm/io.h and test.
881 Example output from the 'iotrace stats' command is below.
882 Note that if the trace buffer is exhausted, the checksum will
883 still continue to operate.
886 Start: 10000000 (buffer start address)
887 Size: 00010000 (buffer size)
888 Offset: 00000120 (current buffer offset)
889 Output: 10000120 (start + offset)
890 Count: 00000018 (number of trace records)
891 CRC32: 9526fb66 (CRC32 of all trace records)
895 When CONFIG_TIMESTAMP is selected, the timestamp
896 (date and time) of an image is printed by image
897 commands like bootm or iminfo. This option is
898 automatically enabled when you select CONFIG_CMD_DATE .
900 - Partition Labels (disklabels) Supported:
901 Zero or more of the following:
902 CONFIG_MAC_PARTITION Apple's MacOS partition table.
903 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
904 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
905 bootloader. Note 2TB partition limit; see
907 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
909 If IDE or SCSI support is enabled (CONFIG_IDE or
910 CONFIG_SCSI) you must configure support for at
911 least one non-MTD partition type as well.
914 CONFIG_IDE_RESET_ROUTINE - this is defined in several
915 board configurations files but used nowhere!
917 CONFIG_IDE_RESET - is this is defined, IDE Reset will
918 be performed by calling the function
919 ide_set_reset(int reset)
920 which has to be defined in a board specific file
925 Set this to enable ATAPI support.
930 Set this to enable support for disks larger than 137GB
931 Also look at CONFIG_SYS_64BIT_LBA.
932 Whithout these , LBA48 support uses 32bit variables and will 'only'
933 support disks up to 2.1TB.
935 CONFIG_SYS_64BIT_LBA:
936 When enabled, makes the IDE subsystem use 64bit sector addresses.
940 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
941 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
942 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
943 maximum numbers of LUNs, SCSI ID's and target
946 The environment variable 'scsidevs' is set to the number of
947 SCSI devices found during the last scan.
949 - NETWORK Support (PCI):
951 Support for Intel 8254x/8257x gigabit chips.
954 Utility code for direct access to the SPI bus on Intel 8257x.
955 This does not do anything useful unless you set at least one
956 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
958 CONFIG_E1000_SPI_GENERIC
959 Allow generic access to the SPI bus on the Intel 8257x, for
960 example with the "sspi" command.
963 Support for Intel 82557/82559/82559ER chips.
964 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
965 write routine for first time initialisation.
968 Support for Digital 2114x chips.
969 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
970 modem chip initialisation (KS8761/QS6611).
973 Support for National dp83815 chips.
976 Support for National dp8382[01] gigabit chips.
978 - NETWORK Support (other):
980 CONFIG_DRIVER_AT91EMAC
981 Support for AT91RM9200 EMAC.
984 Define this to use reduced MII inteface
986 CONFIG_DRIVER_AT91EMAC_QUIET
987 If this defined, the driver is quiet.
988 The driver doen't show link status messages.
991 Support for the Calxeda XGMAC device
994 Support for SMSC's LAN91C96 chips.
996 CONFIG_LAN91C96_USE_32_BIT
997 Define this to enable 32 bit addressing
1000 Support for SMSC's LAN91C111 chip
1002 CONFIG_SMC91111_BASE
1003 Define this to hold the physical address
1004 of the device (I/O space)
1006 CONFIG_SMC_USE_32_BIT
1007 Define this if data bus is 32 bits
1009 CONFIG_SMC_USE_IOFUNCS
1010 Define this to use i/o functions instead of macros
1011 (some hardware wont work with macros)
1013 CONFIG_DRIVER_TI_EMAC
1014 Support for davinci emac
1016 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1017 Define this if you have more then 3 PHYs.
1020 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1022 CONFIG_FTGMAC100_EGIGA
1023 Define this to use GE link update with gigabit PHY.
1024 Define this if FTGMAC100 is connected to gigabit PHY.
1025 If your system has 10/100 PHY only, it might not occur
1026 wrong behavior. Because PHY usually return timeout or
1027 useless data when polling gigabit status and gigabit
1028 control registers. This behavior won't affect the
1029 correctnessof 10/100 link speed update.
1032 Support for SMSC's LAN911x and LAN921x chips
1035 Define this to hold the physical address
1036 of the device (I/O space)
1038 CONFIG_SMC911X_32_BIT
1039 Define this if data bus is 32 bits
1041 CONFIG_SMC911X_16_BIT
1042 Define this if data bus is 16 bits. If your processor
1043 automatically converts one 32 bit word to two 16 bit
1044 words you may also try CONFIG_SMC911X_32_BIT.
1047 Support for Renesas on-chip Ethernet controller
1049 CONFIG_SH_ETHER_USE_PORT
1050 Define the number of ports to be used
1052 CONFIG_SH_ETHER_PHY_ADDR
1053 Define the ETH PHY's address
1055 CONFIG_SH_ETHER_CACHE_WRITEBACK
1056 If this option is set, the driver enables cache flush.
1060 Support for PWM module on the imx6.
1064 Support TPM devices.
1066 CONFIG_TPM_TIS_INFINEON
1067 Support for Infineon i2c bus TPM devices. Only one device
1068 per system is supported at this time.
1070 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1071 Define the burst count bytes upper limit
1074 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1076 CONFIG_TPM_ST33ZP24_I2C
1077 Support for STMicroelectronics ST33ZP24 I2C devices.
1078 Requires TPM_ST33ZP24 and I2C.
1080 CONFIG_TPM_ST33ZP24_SPI
1081 Support for STMicroelectronics ST33ZP24 SPI devices.
1082 Requires TPM_ST33ZP24 and SPI.
1084 CONFIG_TPM_ATMEL_TWI
1085 Support for Atmel TWI TPM device. Requires I2C support.
1088 Support for generic parallel port TPM devices. Only one device
1089 per system is supported at this time.
1091 CONFIG_TPM_TIS_BASE_ADDRESS
1092 Base address where the generic TPM device is mapped
1093 to. Contemporary x86 systems usually map it at
1097 Define this to enable the TPM support library which provides
1098 functional interfaces to some TPM commands.
1099 Requires support for a TPM device.
1101 CONFIG_TPM_AUTH_SESSIONS
1102 Define this to enable authorized functions in the TPM library.
1103 Requires CONFIG_TPM and CONFIG_SHA1.
1106 At the moment only the UHCI host controller is
1107 supported (PIP405, MIP405); define
1108 CONFIG_USB_UHCI to enable it.
1109 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1110 and define CONFIG_USB_STORAGE to enable the USB
1113 Supported are USB Keyboards and USB Floppy drives
1116 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1117 txfilltuning field in the EHCI controller on reset.
1119 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1120 HW module registers.
1123 Define the below if you wish to use the USB console.
1124 Once firmware is rebuilt from a serial console issue the
1125 command "setenv stdin usbtty; setenv stdout usbtty" and
1126 attach your USB cable. The Unix command "dmesg" should print
1127 it has found a new device. The environment variable usbtty
1128 can be set to gserial or cdc_acm to enable your device to
1129 appear to a USB host as a Linux gserial device or a
1130 Common Device Class Abstract Control Model serial device.
1131 If you select usbtty = gserial you should be able to enumerate
1133 # modprobe usbserial vendor=0xVendorID product=0xProductID
1134 else if using cdc_acm, simply setting the environment
1135 variable usbtty to be cdc_acm should suffice. The following
1136 might be defined in YourBoardName.h
1139 Define this to build a UDC device
1142 Define this to have a tty type of device available to
1143 talk to the UDC device
1146 Define this to enable the high speed support for usb
1147 device and usbtty. If this feature is enabled, a routine
1148 int is_usbd_high_speed(void)
1149 also needs to be defined by the driver to dynamically poll
1150 whether the enumeration has succeded at high speed or full
1153 CONFIG_SYS_CONSOLE_IS_IN_ENV
1154 Define this if you want stdin, stdout &/or stderr to
1157 If you have a USB-IF assigned VendorID then you may wish to
1158 define your own vendor specific values either in BoardName.h
1159 or directly in usbd_vendor_info.h. If you don't define
1160 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1161 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1162 should pretend to be a Linux device to it's target host.
1164 CONFIG_USBD_MANUFACTURER
1165 Define this string as the name of your company for
1166 - CONFIG_USBD_MANUFACTURER "my company"
1168 CONFIG_USBD_PRODUCT_NAME
1169 Define this string as the name of your product
1170 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1172 CONFIG_USBD_VENDORID
1173 Define this as your assigned Vendor ID from the USB
1174 Implementors Forum. This *must* be a genuine Vendor ID
1175 to avoid polluting the USB namespace.
1176 - CONFIG_USBD_VENDORID 0xFFFF
1178 CONFIG_USBD_PRODUCTID
1179 Define this as the unique Product ID
1181 - CONFIG_USBD_PRODUCTID 0xFFFF
1183 - ULPI Layer Support:
1184 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1185 the generic ULPI layer. The generic layer accesses the ULPI PHY
1186 via the platform viewport, so you need both the genric layer and
1187 the viewport enabled. Currently only Chipidea/ARC based
1188 viewport is supported.
1189 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1190 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1191 If your ULPI phy needs a different reference clock than the
1192 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1193 the appropriate value in Hz.
1196 The MMC controller on the Intel PXA is supported. To
1197 enable this define CONFIG_MMC. The MMC can be
1198 accessed from the boot prompt by mapping the device
1199 to physical memory similar to flash. Command line is
1200 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1201 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1204 Support for Renesas on-chip MMCIF controller
1206 CONFIG_SH_MMCIF_ADDR
1207 Define the base address of MMCIF registers
1210 Define the clock frequency for MMCIF
1212 CONFIG_SUPPORT_EMMC_BOOT
1213 Enable some additional features of the eMMC boot partitions.
1215 CONFIG_SUPPORT_EMMC_RPMB
1216 Enable the commands for reading, writing and programming the
1217 key for the Replay Protection Memory Block partition in eMMC.
1219 - USB Device Firmware Update (DFU) class support:
1220 CONFIG_USB_FUNCTION_DFU
1221 This enables the USB portion of the DFU USB class
1224 This enables support for exposing (e)MMC devices via DFU.
1227 This enables support for exposing NAND devices via DFU.
1230 This enables support for exposing RAM via DFU.
1231 Note: DFU spec refer to non-volatile memory usage, but
1232 allow usages beyond the scope of spec - here RAM usage,
1233 one that would help mostly the developer.
1235 CONFIG_SYS_DFU_DATA_BUF_SIZE
1236 Dfu transfer uses a buffer before writing data to the
1237 raw storage device. Make the size (in bytes) of this buffer
1238 configurable. The size of this buffer is also configurable
1239 through the "dfu_bufsiz" environment variable.
1241 CONFIG_SYS_DFU_MAX_FILE_SIZE
1242 When updating files rather than the raw storage device,
1243 we use a static buffer to copy the file into and then write
1244 the buffer once we've been given the whole file. Define
1245 this to the maximum filesize (in bytes) for the buffer.
1246 Default is 4 MiB if undefined.
1248 DFU_DEFAULT_POLL_TIMEOUT
1249 Poll timeout [ms], is the timeout a device can send to the
1250 host. The host must wait for this timeout before sending
1251 a subsequent DFU_GET_STATUS request to the device.
1253 DFU_MANIFEST_POLL_TIMEOUT
1254 Poll timeout [ms], which the device sends to the host when
1255 entering dfuMANIFEST state. Host waits this timeout, before
1256 sending again an USB request to the device.
1258 - Journaling Flash filesystem support:
1260 Define these for a default partition on a NAND device
1262 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1263 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1264 Define these for a default partition on a NOR device
1267 See Kconfig help for available keyboard drivers.
1271 Define this to enable a custom keyboard support.
1272 This simply calls drv_keyboard_init() which must be
1273 defined in your board-specific files. This option is deprecated
1274 and is only used by novena. For new boards, use driver model
1279 Enable the Freescale DIU video driver. Reference boards for
1280 SOCs that have a DIU should define this macro to enable DIU
1281 support, and should also define these other macros:
1286 CONFIG_VIDEO_SW_CURSOR
1287 CONFIG_VGA_AS_SINGLE_DEVICE
1289 CONFIG_VIDEO_BMP_LOGO
1291 The DIU driver will look for the 'video-mode' environment
1292 variable, and if defined, enable the DIU as a console during
1293 boot. See the documentation file doc/README.video for a
1294 description of this variable.
1296 - LCD Support: CONFIG_LCD
1298 Define this to enable LCD support (for output to LCD
1299 display); also select one of the supported displays
1300 by defining one of these:
1304 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1306 CONFIG_NEC_NL6448AC33:
1308 NEC NL6448AC33-18. Active, color, single scan.
1310 CONFIG_NEC_NL6448BC20
1312 NEC NL6448BC20-08. 6.5", 640x480.
1313 Active, color, single scan.
1315 CONFIG_NEC_NL6448BC33_54
1317 NEC NL6448BC33-54. 10.4", 640x480.
1318 Active, color, single scan.
1322 Sharp 320x240. Active, color, single scan.
1323 It isn't 16x9, and I am not sure what it is.
1325 CONFIG_SHARP_LQ64D341
1327 Sharp LQ64D341 display, 640x480.
1328 Active, color, single scan.
1332 HLD1045 display, 640x480.
1333 Active, color, single scan.
1337 Optrex CBL50840-2 NF-FW 99 22 M5
1339 Hitachi LMG6912RPFC-00T
1343 320x240. Black & white.
1345 CONFIG_LCD_ALIGNMENT
1347 Normally the LCD is page-aligned (typically 4KB). If this is
1348 defined then the LCD will be aligned to this value instead.
1349 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1350 here, since it is cheaper to change data cache settings on
1351 a per-section basis.
1356 Sometimes, for example if the display is mounted in portrait
1357 mode or even if it's mounted landscape but rotated by 180degree,
1358 we need to rotate our content of the display relative to the
1359 framebuffer, so that user can read the messages which are
1361 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1362 initialized with a given rotation from "vl_rot" out of
1363 "vidinfo_t" which is provided by the board specific code.
1364 The value for vl_rot is coded as following (matching to
1365 fbcon=rotate:<n> linux-kernel commandline):
1366 0 = no rotation respectively 0 degree
1367 1 = 90 degree rotation
1368 2 = 180 degree rotation
1369 3 = 270 degree rotation
1371 If CONFIG_LCD_ROTATION is not defined, the console will be
1372 initialized with 0degree rotation.
1376 Support drawing of RLE8-compressed bitmaps on the LCD.
1380 Enables an 'i2c edid' command which can read EDID
1381 information over I2C from an attached LCD display.
1383 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1385 If this option is set, the environment is checked for
1386 a variable "splashimage". If found, the usual display
1387 of logo, copyright and system information on the LCD
1388 is suppressed and the BMP image at the address
1389 specified in "splashimage" is loaded instead. The
1390 console is redirected to the "nulldev", too. This
1391 allows for a "silent" boot where a splash screen is
1392 loaded very quickly after power-on.
1394 CONFIG_SPLASHIMAGE_GUARD
1396 If this option is set, then U-Boot will prevent the environment
1397 variable "splashimage" from being set to a problematic address
1398 (see doc/README.displaying-bmps).
1399 This option is useful for targets where, due to alignment
1400 restrictions, an improperly aligned BMP image will cause a data
1401 abort. If you think you will not have problems with unaligned
1402 accesses (for example because your toolchain prevents them)
1403 there is no need to set this option.
1405 CONFIG_SPLASH_SCREEN_ALIGN
1407 If this option is set the splash image can be freely positioned
1408 on the screen. Environment variable "splashpos" specifies the
1409 position as "x,y". If a positive number is given it is used as
1410 number of pixel from left/top. If a negative number is given it
1411 is used as number of pixel from right/bottom. You can also
1412 specify 'm' for centering the image.
1415 setenv splashpos m,m
1416 => image at center of screen
1418 setenv splashpos 30,20
1419 => image at x = 30 and y = 20
1421 setenv splashpos -10,m
1422 => vertically centered image
1423 at x = dspWidth - bmpWidth - 9
1425 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1427 If this option is set, additionally to standard BMP
1428 images, gzipped BMP images can be displayed via the
1429 splashscreen support or the bmp command.
1431 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1433 If this option is set, 8-bit RLE compressed BMP images
1434 can be displayed via the splashscreen support or the
1437 - Compression support:
1440 Enabled by default to support gzip compressed images.
1444 If this option is set, support for bzip2 compressed
1445 images is included. If not, only uncompressed and gzip
1446 compressed images are supported.
1448 NOTE: the bzip2 algorithm requires a lot of RAM, so
1449 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1455 The address of PHY on MII bus.
1457 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1459 The clock frequency of the MII bus
1461 CONFIG_PHY_RESET_DELAY
1463 Some PHY like Intel LXT971A need extra delay after
1464 reset before any MII register access is possible.
1465 For such PHY, set this option to the usec delay
1466 required. (minimum 300usec for LXT971A)
1468 CONFIG_PHY_CMD_DELAY (ppc4xx)
1470 Some PHY like Intel LXT971A need extra delay after
1471 command issued before MII status register can be read
1476 Define a default value for the IP address to use for
1477 the default Ethernet interface, in case this is not
1478 determined through e.g. bootp.
1479 (Environment variable "ipaddr")
1481 - Server IP address:
1484 Defines a default value for the IP address of a TFTP
1485 server to contact when using the "tftboot" command.
1486 (Environment variable "serverip")
1488 CONFIG_KEEP_SERVERADDR
1490 Keeps the server's MAC address, in the env 'serveraddr'
1491 for passing to bootargs (like Linux's netconsole option)
1493 - Gateway IP address:
1496 Defines a default value for the IP address of the
1497 default router where packets to other networks are
1499 (Environment variable "gatewayip")
1504 Defines a default value for the subnet mask (or
1505 routing prefix) which is used to determine if an IP
1506 address belongs to the local subnet or needs to be
1507 forwarded through a router.
1508 (Environment variable "netmask")
1510 - Multicast TFTP Mode:
1513 Defines whether you want to support multicast TFTP as per
1514 rfc-2090; for example to work with atftp. Lets lots of targets
1515 tftp down the same boot image concurrently. Note: the Ethernet
1516 driver in use must provide a function: mcast() to join/leave a
1519 - BOOTP Recovery Mode:
1520 CONFIG_BOOTP_RANDOM_DELAY
1522 If you have many targets in a network that try to
1523 boot using BOOTP, you may want to avoid that all
1524 systems send out BOOTP requests at precisely the same
1525 moment (which would happen for instance at recovery
1526 from a power failure, when all systems will try to
1527 boot, thus flooding the BOOTP server. Defining
1528 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1529 inserted before sending out BOOTP requests. The
1530 following delays are inserted then:
1532 1st BOOTP request: delay 0 ... 1 sec
1533 2nd BOOTP request: delay 0 ... 2 sec
1534 3rd BOOTP request: delay 0 ... 4 sec
1536 BOOTP requests: delay 0 ... 8 sec
1538 CONFIG_BOOTP_ID_CACHE_SIZE
1540 BOOTP packets are uniquely identified using a 32-bit ID. The
1541 server will copy the ID from client requests to responses and
1542 U-Boot will use this to determine if it is the destination of
1543 an incoming response. Some servers will check that addresses
1544 aren't in use before handing them out (usually using an ARP
1545 ping) and therefore take up to a few hundred milliseconds to
1546 respond. Network congestion may also influence the time it
1547 takes for a response to make it back to the client. If that
1548 time is too long, U-Boot will retransmit requests. In order
1549 to allow earlier responses to still be accepted after these
1550 retransmissions, U-Boot's BOOTP client keeps a small cache of
1551 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1552 cache. The default is to keep IDs for up to four outstanding
1553 requests. Increasing this will allow U-Boot to accept offers
1554 from a BOOTP client in networks with unusually high latency.
1556 - DHCP Advanced Options:
1557 You can fine tune the DHCP functionality by defining
1558 CONFIG_BOOTP_* symbols:
1560 CONFIG_BOOTP_SUBNETMASK
1561 CONFIG_BOOTP_GATEWAY
1562 CONFIG_BOOTP_HOSTNAME
1563 CONFIG_BOOTP_NISDOMAIN
1564 CONFIG_BOOTP_BOOTPATH
1565 CONFIG_BOOTP_BOOTFILESIZE
1568 CONFIG_BOOTP_SEND_HOSTNAME
1569 CONFIG_BOOTP_NTPSERVER
1570 CONFIG_BOOTP_TIMEOFFSET
1571 CONFIG_BOOTP_VENDOREX
1572 CONFIG_BOOTP_MAY_FAIL
1574 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1575 environment variable, not the BOOTP server.
1577 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1578 after the configured retry count, the call will fail
1579 instead of starting over. This can be used to fail over
1580 to Link-local IP address configuration if the DHCP server
1583 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1584 serverip from a DHCP server, it is possible that more
1585 than one DNS serverip is offered to the client.
1586 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1587 serverip will be stored in the additional environment
1588 variable "dnsip2". The first DNS serverip is always
1589 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1592 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1593 to do a dynamic update of a DNS server. To do this, they
1594 need the hostname of the DHCP requester.
1595 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1596 of the "hostname" environment variable is passed as
1597 option 12 to the DHCP server.
1599 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1601 A 32bit value in microseconds for a delay between
1602 receiving a "DHCP Offer" and sending the "DHCP Request".
1603 This fixes a problem with certain DHCP servers that don't
1604 respond 100% of the time to a "DHCP request". E.g. On an
1605 AT91RM9200 processor running at 180MHz, this delay needed
1606 to be *at least* 15,000 usec before a Windows Server 2003
1607 DHCP server would reply 100% of the time. I recommend at
1608 least 50,000 usec to be safe. The alternative is to hope
1609 that one of the retries will be successful but note that
1610 the DHCP timeout and retry process takes a longer than
1613 - Link-local IP address negotiation:
1614 Negotiate with other link-local clients on the local network
1615 for an address that doesn't require explicit configuration.
1616 This is especially useful if a DHCP server cannot be guaranteed
1617 to exist in all environments that the device must operate.
1619 See doc/README.link-local for more information.
1622 CONFIG_CDP_DEVICE_ID
1624 The device id used in CDP trigger frames.
1626 CONFIG_CDP_DEVICE_ID_PREFIX
1628 A two character string which is prefixed to the MAC address
1633 A printf format string which contains the ascii name of
1634 the port. Normally is set to "eth%d" which sets
1635 eth0 for the first Ethernet, eth1 for the second etc.
1637 CONFIG_CDP_CAPABILITIES
1639 A 32bit integer which indicates the device capabilities;
1640 0x00000010 for a normal host which does not forwards.
1644 An ascii string containing the version of the software.
1648 An ascii string containing the name of the platform.
1652 A 32bit integer sent on the trigger.
1654 CONFIG_CDP_POWER_CONSUMPTION
1656 A 16bit integer containing the power consumption of the
1657 device in .1 of milliwatts.
1659 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1661 A byte containing the id of the VLAN.
1663 - Status LED: CONFIG_LED_STATUS
1665 Several configurations allow to display the current
1666 status using a LED. For instance, the LED will blink
1667 fast while running U-Boot code, stop blinking as
1668 soon as a reply to a BOOTP request was received, and
1669 start blinking slow once the Linux kernel is running
1670 (supported by a status LED driver in the Linux
1671 kernel). Defining CONFIG_LED_STATUS enables this
1676 CONFIG_LED_STATUS_GPIO
1677 The status LED can be connected to a GPIO pin.
1678 In such cases, the gpio_led driver can be used as a
1679 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1680 to include the gpio_led driver in the U-Boot binary.
1682 CONFIG_GPIO_LED_INVERTED_TABLE
1683 Some GPIO connected LEDs may have inverted polarity in which
1684 case the GPIO high value corresponds to LED off state and
1685 GPIO low value corresponds to LED on state.
1686 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1687 with a list of GPIO LEDs that have inverted polarity.
1689 - I2C Support: CONFIG_SYS_I2C
1691 This enable the NEW i2c subsystem, and will allow you to use
1692 i2c commands at the u-boot command line (as long as you set
1693 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1694 based realtime clock chips or other i2c devices. See
1695 common/cmd_i2c.c for a description of the command line
1698 ported i2c driver to the new framework:
1699 - drivers/i2c/soft_i2c.c:
1700 - activate first bus with CONFIG_SYS_I2C_SOFT define
1701 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1702 for defining speed and slave address
1703 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1704 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1705 for defining speed and slave address
1706 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1707 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1708 for defining speed and slave address
1709 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1710 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1711 for defining speed and slave address
1713 - drivers/i2c/fsl_i2c.c:
1714 - activate i2c driver with CONFIG_SYS_I2C_FSL
1715 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1716 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1717 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1719 - If your board supports a second fsl i2c bus, define
1720 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1721 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1722 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1725 - drivers/i2c/tegra_i2c.c:
1726 - activate this driver with CONFIG_SYS_I2C_TEGRA
1727 - This driver adds 4 i2c buses with a fix speed from
1728 100000 and the slave addr 0!
1730 - drivers/i2c/ppc4xx_i2c.c
1731 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1732 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1733 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1735 - drivers/i2c/i2c_mxc.c
1736 - activate this driver with CONFIG_SYS_I2C_MXC
1737 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1738 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1739 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1740 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1741 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1742 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1743 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1744 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1745 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1746 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1747 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1748 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1749 If those defines are not set, default value is 100000
1750 for speed, and 0 for slave.
1752 - drivers/i2c/rcar_i2c.c:
1753 - activate this driver with CONFIG_SYS_I2C_RCAR
1754 - This driver adds 4 i2c buses
1756 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1757 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1758 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1759 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1760 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1761 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1762 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1763 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1764 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1766 - drivers/i2c/sh_i2c.c:
1767 - activate this driver with CONFIG_SYS_I2C_SH
1768 - This driver adds from 2 to 5 i2c buses
1770 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1771 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1772 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1773 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1774 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1775 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1776 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1777 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1778 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1779 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1780 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1782 - drivers/i2c/omap24xx_i2c.c
1783 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1784 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1785 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1786 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1787 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1788 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1789 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1790 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1791 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1792 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1793 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1795 - drivers/i2c/zynq_i2c.c
1796 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1797 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1798 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1800 - drivers/i2c/s3c24x0_i2c.c:
1801 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1802 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1803 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1804 with a fix speed from 100000 and the slave addr 0!
1806 - drivers/i2c/ihs_i2c.c
1807 - activate this driver with CONFIG_SYS_I2C_IHS
1808 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1809 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1810 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1811 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1812 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1813 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1814 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1815 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1816 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1817 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1818 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1819 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1820 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1821 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1822 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1823 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1824 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1825 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1826 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1827 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1828 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1832 CONFIG_SYS_NUM_I2C_BUSES
1833 Hold the number of i2c buses you want to use.
1835 CONFIG_SYS_I2C_DIRECT_BUS
1836 define this, if you don't use i2c muxes on your hardware.
1837 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1840 CONFIG_SYS_I2C_MAX_HOPS
1841 define how many muxes are maximal consecutively connected
1842 on one i2c bus. If you not use i2c muxes, omit this
1845 CONFIG_SYS_I2C_BUSES
1846 hold a list of buses you want to use, only used if
1847 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1848 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1849 CONFIG_SYS_NUM_I2C_BUSES = 9:
1851 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1852 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1853 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1854 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1855 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1856 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1857 {1, {I2C_NULL_HOP}}, \
1858 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1859 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1863 bus 0 on adapter 0 without a mux
1864 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1865 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1866 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1867 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1868 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1869 bus 6 on adapter 1 without a mux
1870 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1871 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1873 If you do not have i2c muxes on your board, omit this define.
1875 - Legacy I2C Support:
1876 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1877 then the following macros need to be defined (examples are
1878 from include/configs/lwmon.h):
1882 (Optional). Any commands necessary to enable the I2C
1883 controller or configure ports.
1885 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1889 The code necessary to make the I2C data line active
1890 (driven). If the data line is open collector, this
1893 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1897 The code necessary to make the I2C data line tri-stated
1898 (inactive). If the data line is open collector, this
1901 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1905 Code that returns true if the I2C data line is high,
1908 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1912 If <bit> is true, sets the I2C data line high. If it
1913 is false, it clears it (low).
1915 eg: #define I2C_SDA(bit) \
1916 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1917 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1921 If <bit> is true, sets the I2C clock line high. If it
1922 is false, it clears it (low).
1924 eg: #define I2C_SCL(bit) \
1925 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1926 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1930 This delay is invoked four times per clock cycle so this
1931 controls the rate of data transfer. The data rate thus
1932 is 1 / (I2C_DELAY * 4). Often defined to be something
1935 #define I2C_DELAY udelay(2)
1937 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1939 If your arch supports the generic GPIO framework (asm/gpio.h),
1940 then you may alternatively define the two GPIOs that are to be
1941 used as SCL / SDA. Any of the previous I2C_xxx macros will
1942 have GPIO-based defaults assigned to them as appropriate.
1944 You should define these to the GPIO value as given directly to
1945 the generic GPIO functions.
1947 CONFIG_SYS_I2C_INIT_BOARD
1949 When a board is reset during an i2c bus transfer
1950 chips might think that the current transfer is still
1951 in progress. On some boards it is possible to access
1952 the i2c SCLK line directly, either by using the
1953 processor pin as a GPIO or by having a second pin
1954 connected to the bus. If this option is defined a
1955 custom i2c_init_board() routine in boards/xxx/board.c
1956 is run early in the boot sequence.
1958 CONFIG_I2C_MULTI_BUS
1960 This option allows the use of multiple I2C buses, each of which
1961 must have a controller. At any point in time, only one bus is
1962 active. To switch to a different bus, use the 'i2c dev' command.
1963 Note that bus numbering is zero-based.
1965 CONFIG_SYS_I2C_NOPROBES
1967 This option specifies a list of I2C devices that will be skipped
1968 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1969 is set, specify a list of bus-device pairs. Otherwise, specify
1970 a 1D array of device addresses
1973 #undef CONFIG_I2C_MULTI_BUS
1974 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1976 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1978 #define CONFIG_I2C_MULTI_BUS
1979 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1981 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1983 CONFIG_SYS_SPD_BUS_NUM
1985 If defined, then this indicates the I2C bus number for DDR SPD.
1986 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1988 CONFIG_SYS_RTC_BUS_NUM
1990 If defined, then this indicates the I2C bus number for the RTC.
1991 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1993 CONFIG_SOFT_I2C_READ_REPEATED_START
1995 defining this will force the i2c_read() function in
1996 the soft_i2c driver to perform an I2C repeated start
1997 between writing the address pointer and reading the
1998 data. If this define is omitted the default behaviour
1999 of doing a stop-start sequence will be used. Most I2C
2000 devices can use either method, but some require one or
2003 - SPI Support: CONFIG_SPI
2005 Enables SPI driver (so far only tested with
2006 SPI EEPROM, also an instance works with Crystal A/D and
2007 D/As on the SACSng board)
2011 Enables the driver for SPI controller on SuperH. Currently
2012 only SH7757 is supported.
2016 Enables a software (bit-bang) SPI driver rather than
2017 using hardware support. This is a general purpose
2018 driver that only requires three general I/O port pins
2019 (two outputs, one input) to function. If this is
2020 defined, the board configuration must define several
2021 SPI configuration items (port pins to use, etc). For
2022 an example, see include/configs/sacsng.h.
2026 Enables a hardware SPI driver for general-purpose reads
2027 and writes. As with CONFIG_SOFT_SPI, the board configuration
2028 must define a list of chip-select function pointers.
2029 Currently supported on some MPC8xxx processors. For an
2030 example, see include/configs/mpc8349emds.h.
2034 Enables the driver for the SPI controllers on i.MX and MXC
2035 SoCs. Currently i.MX31/35/51 are supported.
2037 CONFIG_SYS_SPI_MXC_WAIT
2038 Timeout for waiting until spi transfer completed.
2039 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2041 - FPGA Support: CONFIG_FPGA
2043 Enables FPGA subsystem.
2045 CONFIG_FPGA_<vendor>
2047 Enables support for specific chip vendors.
2050 CONFIG_FPGA_<family>
2052 Enables support for FPGA family.
2053 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2057 Specify the number of FPGA devices to support.
2059 CONFIG_SYS_FPGA_PROG_FEEDBACK
2061 Enable printing of hash marks during FPGA configuration.
2063 CONFIG_SYS_FPGA_CHECK_BUSY
2065 Enable checks on FPGA configuration interface busy
2066 status by the configuration function. This option
2067 will require a board or device specific function to
2072 If defined, a function that provides delays in the FPGA
2073 configuration driver.
2075 CONFIG_SYS_FPGA_CHECK_CTRLC
2076 Allow Control-C to interrupt FPGA configuration
2078 CONFIG_SYS_FPGA_CHECK_ERROR
2080 Check for configuration errors during FPGA bitfile
2081 loading. For example, abort during Virtex II
2082 configuration if the INIT_B line goes low (which
2083 indicated a CRC error).
2085 CONFIG_SYS_FPGA_WAIT_INIT
2087 Maximum time to wait for the INIT_B line to de-assert
2088 after PROB_B has been de-asserted during a Virtex II
2089 FPGA configuration sequence. The default time is 500
2092 CONFIG_SYS_FPGA_WAIT_BUSY
2094 Maximum time to wait for BUSY to de-assert during
2095 Virtex II FPGA configuration. The default is 5 ms.
2097 CONFIG_SYS_FPGA_WAIT_CONFIG
2099 Time to wait after FPGA configuration. The default is
2102 - Configuration Management:
2105 Some SoCs need special image types (e.g. U-Boot binary
2106 with a special header) as build targets. By defining
2107 CONFIG_BUILD_TARGET in the SoC / board header, this
2108 special image will be automatically built upon calling
2113 If defined, this string will be added to the U-Boot
2114 version information (U_BOOT_VERSION)
2116 - Vendor Parameter Protection:
2118 U-Boot considers the values of the environment
2119 variables "serial#" (Board Serial Number) and
2120 "ethaddr" (Ethernet Address) to be parameters that
2121 are set once by the board vendor / manufacturer, and
2122 protects these variables from casual modification by
2123 the user. Once set, these variables are read-only,
2124 and write or delete attempts are rejected. You can
2125 change this behaviour:
2127 If CONFIG_ENV_OVERWRITE is #defined in your config
2128 file, the write protection for vendor parameters is
2129 completely disabled. Anybody can change or delete
2132 Alternatively, if you define _both_ an ethaddr in the
2133 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2134 Ethernet address is installed in the environment,
2135 which can be changed exactly ONCE by the user. [The
2136 serial# is unaffected by this, i. e. it remains
2139 The same can be accomplished in a more flexible way
2140 for any variable by configuring the type of access
2141 to allow for those variables in the ".flags" variable
2142 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2147 Define this variable to enable the reservation of
2148 "protected RAM", i. e. RAM which is not overwritten
2149 by U-Boot. Define CONFIG_PRAM to hold the number of
2150 kB you want to reserve for pRAM. You can overwrite
2151 this default value by defining an environment
2152 variable "pram" to the number of kB you want to
2153 reserve. Note that the board info structure will
2154 still show the full amount of RAM. If pRAM is
2155 reserved, a new environment variable "mem" will
2156 automatically be defined to hold the amount of
2157 remaining RAM in a form that can be passed as boot
2158 argument to Linux, for instance like that:
2160 setenv bootargs ... mem=\${mem}
2163 This way you can tell Linux not to use this memory,
2164 either, which results in a memory region that will
2165 not be affected by reboots.
2167 *WARNING* If your board configuration uses automatic
2168 detection of the RAM size, you must make sure that
2169 this memory test is non-destructive. So far, the
2170 following board configurations are known to be
2173 IVMS8, IVML24, SPD8xx,
2174 HERMES, IP860, RPXlite, LWMON,
2177 - Access to physical memory region (> 4GB)
2178 Some basic support is provided for operations on memory not
2179 normally accessible to U-Boot - e.g. some architectures
2180 support access to more than 4GB of memory on 32-bit
2181 machines using physical address extension or similar.
2182 Define CONFIG_PHYSMEM to access this basic support, which
2183 currently only supports clearing the memory.
2188 Define this variable to stop the system in case of a
2189 fatal error, so that you have to reset it manually.
2190 This is probably NOT a good idea for an embedded
2191 system where you want the system to reboot
2192 automatically as fast as possible, but it may be
2193 useful during development since you can try to debug
2194 the conditions that lead to the situation.
2196 CONFIG_NET_RETRY_COUNT
2198 This variable defines the number of retries for
2199 network operations like ARP, RARP, TFTP, or BOOTP
2200 before giving up the operation. If not defined, a
2201 default value of 5 is used.
2205 Timeout waiting for an ARP reply in milliseconds.
2209 Timeout in milliseconds used in NFS protocol.
2210 If you encounter "ERROR: Cannot umount" in nfs command,
2211 try longer timeout such as
2212 #define CONFIG_NFS_TIMEOUT 10000UL
2214 - Command Interpreter:
2215 CONFIG_AUTO_COMPLETE
2217 Enable auto completion of commands using TAB.
2219 CONFIG_SYS_PROMPT_HUSH_PS2
2221 This defines the secondary prompt string, which is
2222 printed when the command interpreter needs more input
2223 to complete a command. Usually "> ".
2227 In the current implementation, the local variables
2228 space and global environment variables space are
2229 separated. Local variables are those you define by
2230 simply typing `name=value'. To access a local
2231 variable later on, you have write `$name' or
2232 `${name}'; to execute the contents of a variable
2233 directly type `$name' at the command prompt.
2235 Global environment variables are those you use
2236 setenv/printenv to work with. To run a command stored
2237 in such a variable, you need to use the run command,
2238 and you must not use the '$' sign to access them.
2240 To store commands and special characters in a
2241 variable, please use double quotation marks
2242 surrounding the whole text of the variable, instead
2243 of the backslashes before semicolons and special
2246 - Command Line Editing and History:
2247 CONFIG_CMDLINE_EDITING
2249 Enable editing and History functions for interactive
2250 command line input operations
2252 - Command Line PS1/PS2 support:
2253 CONFIG_CMDLINE_PS_SUPPORT
2255 Enable support for changing the command prompt string
2256 at run-time. Only static string is supported so far.
2257 The string is obtained from environment variables PS1
2260 - Default Environment:
2261 CONFIG_EXTRA_ENV_SETTINGS
2263 Define this to contain any number of null terminated
2264 strings (variable = value pairs) that will be part of
2265 the default environment compiled into the boot image.
2267 For example, place something like this in your
2268 board's config file:
2270 #define CONFIG_EXTRA_ENV_SETTINGS \
2274 Warning: This method is based on knowledge about the
2275 internal format how the environment is stored by the
2276 U-Boot code. This is NOT an official, exported
2277 interface! Although it is unlikely that this format
2278 will change soon, there is no guarantee either.
2279 You better know what you are doing here.
2281 Note: overly (ab)use of the default environment is
2282 discouraged. Make sure to check other ways to preset
2283 the environment like the "source" command or the
2286 CONFIG_ENV_VARS_UBOOT_CONFIG
2288 Define this in order to add variables describing the
2289 U-Boot build configuration to the default environment.
2290 These will be named arch, cpu, board, vendor, and soc.
2292 Enabling this option will cause the following to be defined:
2300 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2302 Define this in order to add variables describing certain
2303 run-time determined information about the hardware to the
2304 environment. These will be named board_name, board_rev.
2306 CONFIG_DELAY_ENVIRONMENT
2308 Normally the environment is loaded when the board is
2309 initialised so that it is available to U-Boot. This inhibits
2310 that so that the environment is not available until
2311 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2312 this is instead controlled by the value of
2313 /config/load-environment.
2315 - DataFlash Support:
2316 CONFIG_HAS_DATAFLASH
2318 Defining this option enables DataFlash features and
2319 allows to read/write in Dataflash via the standard
2322 - Serial Flash support
2323 Usage requires an initial 'sf probe' to define the serial
2324 flash parameters, followed by read/write/erase/update
2327 The following defaults may be provided by the platform
2328 to handle the common case when only a single serial
2329 flash is present on the system.
2331 CONFIG_SF_DEFAULT_BUS Bus identifier
2332 CONFIG_SF_DEFAULT_CS Chip-select
2333 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2334 CONFIG_SF_DEFAULT_SPEED in Hz
2338 Adding this option adds support for Xilinx SystemACE
2339 chips attached via some sort of local bus. The address
2340 of the chip must also be defined in the
2341 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2343 #define CONFIG_SYSTEMACE
2344 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2346 When SystemACE support is added, the "ace" device type
2347 becomes available to the fat commands, i.e. fatls.
2349 - TFTP Fixed UDP Port:
2352 If this is defined, the environment variable tftpsrcp
2353 is used to supply the TFTP UDP source port value.
2354 If tftpsrcp isn't defined, the normal pseudo-random port
2355 number generator is used.
2357 Also, the environment variable tftpdstp is used to supply
2358 the TFTP UDP destination port value. If tftpdstp isn't
2359 defined, the normal port 69 is used.
2361 The purpose for tftpsrcp is to allow a TFTP server to
2362 blindly start the TFTP transfer using the pre-configured
2363 target IP address and UDP port. This has the effect of
2364 "punching through" the (Windows XP) firewall, allowing
2365 the remainder of the TFTP transfer to proceed normally.
2366 A better solution is to properly configure the firewall,
2367 but sometimes that is not allowed.
2369 - bootcount support:
2370 CONFIG_BOOTCOUNT_LIMIT
2372 This enables the bootcounter support, see:
2373 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2376 enable special bootcounter support on at91sam9xe based boards.
2378 enable special bootcounter support on da850 based boards.
2379 CONFIG_BOOTCOUNT_RAM
2380 enable support for the bootcounter in RAM
2381 CONFIG_BOOTCOUNT_I2C
2382 enable support for the bootcounter on an i2c (like RTC) device.
2383 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2384 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2386 CONFIG_BOOTCOUNT_ALEN = address len
2388 - Show boot progress:
2389 CONFIG_SHOW_BOOT_PROGRESS
2391 Defining this option allows to add some board-
2392 specific code (calling a user-provided function
2393 "show_boot_progress(int)") that enables you to show
2394 the system's boot progress on some display (for
2395 example, some LED's) on your board. At the moment,
2396 the following checkpoints are implemented:
2399 Legacy uImage format:
2402 1 common/cmd_bootm.c before attempting to boot an image
2403 -1 common/cmd_bootm.c Image header has bad magic number
2404 2 common/cmd_bootm.c Image header has correct magic number
2405 -2 common/cmd_bootm.c Image header has bad checksum
2406 3 common/cmd_bootm.c Image header has correct checksum
2407 -3 common/cmd_bootm.c Image data has bad checksum
2408 4 common/cmd_bootm.c Image data has correct checksum
2409 -4 common/cmd_bootm.c Image is for unsupported architecture
2410 5 common/cmd_bootm.c Architecture check OK
2411 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2412 6 common/cmd_bootm.c Image Type check OK
2413 -6 common/cmd_bootm.c gunzip uncompression error
2414 -7 common/cmd_bootm.c Unimplemented compression type
2415 7 common/cmd_bootm.c Uncompression OK
2416 8 common/cmd_bootm.c No uncompress/copy overwrite error
2417 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2419 9 common/image.c Start initial ramdisk verification
2420 -10 common/image.c Ramdisk header has bad magic number
2421 -11 common/image.c Ramdisk header has bad checksum
2422 10 common/image.c Ramdisk header is OK
2423 -12 common/image.c Ramdisk data has bad checksum
2424 11 common/image.c Ramdisk data has correct checksum
2425 12 common/image.c Ramdisk verification complete, start loading
2426 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2427 13 common/image.c Start multifile image verification
2428 14 common/image.c No initial ramdisk, no multifile, continue.
2430 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2432 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2433 -31 post/post.c POST test failed, detected by post_output_backlog()
2434 -32 post/post.c POST test failed, detected by post_run_single()
2436 34 common/cmd_doc.c before loading a Image from a DOC device
2437 -35 common/cmd_doc.c Bad usage of "doc" command
2438 35 common/cmd_doc.c correct usage of "doc" command
2439 -36 common/cmd_doc.c No boot device
2440 36 common/cmd_doc.c correct boot device
2441 -37 common/cmd_doc.c Unknown Chip ID on boot device
2442 37 common/cmd_doc.c correct chip ID found, device available
2443 -38 common/cmd_doc.c Read Error on boot device
2444 38 common/cmd_doc.c reading Image header from DOC device OK
2445 -39 common/cmd_doc.c Image header has bad magic number
2446 39 common/cmd_doc.c Image header has correct magic number
2447 -40 common/cmd_doc.c Error reading Image from DOC device
2448 40 common/cmd_doc.c Image header has correct magic number
2449 41 common/cmd_ide.c before loading a Image from a IDE device
2450 -42 common/cmd_ide.c Bad usage of "ide" command
2451 42 common/cmd_ide.c correct usage of "ide" command
2452 -43 common/cmd_ide.c No boot device
2453 43 common/cmd_ide.c boot device found
2454 -44 common/cmd_ide.c Device not available
2455 44 common/cmd_ide.c Device available
2456 -45 common/cmd_ide.c wrong partition selected
2457 45 common/cmd_ide.c partition selected
2458 -46 common/cmd_ide.c Unknown partition table
2459 46 common/cmd_ide.c valid partition table found
2460 -47 common/cmd_ide.c Invalid partition type
2461 47 common/cmd_ide.c correct partition type
2462 -48 common/cmd_ide.c Error reading Image Header on boot device
2463 48 common/cmd_ide.c reading Image Header from IDE device OK
2464 -49 common/cmd_ide.c Image header has bad magic number
2465 49 common/cmd_ide.c Image header has correct magic number
2466 -50 common/cmd_ide.c Image header has bad checksum
2467 50 common/cmd_ide.c Image header has correct checksum
2468 -51 common/cmd_ide.c Error reading Image from IDE device
2469 51 common/cmd_ide.c reading Image from IDE device OK
2470 52 common/cmd_nand.c before loading a Image from a NAND device
2471 -53 common/cmd_nand.c Bad usage of "nand" command
2472 53 common/cmd_nand.c correct usage of "nand" command
2473 -54 common/cmd_nand.c No boot device
2474 54 common/cmd_nand.c boot device found
2475 -55 common/cmd_nand.c Unknown Chip ID on boot device
2476 55 common/cmd_nand.c correct chip ID found, device available
2477 -56 common/cmd_nand.c Error reading Image Header on boot device
2478 56 common/cmd_nand.c reading Image Header from NAND device OK
2479 -57 common/cmd_nand.c Image header has bad magic number
2480 57 common/cmd_nand.c Image header has correct magic number
2481 -58 common/cmd_nand.c Error reading Image from NAND device
2482 58 common/cmd_nand.c reading Image from NAND device OK
2484 -60 common/env_common.c Environment has a bad CRC, using default
2486 64 net/eth.c starting with Ethernet configuration.
2487 -64 net/eth.c no Ethernet found.
2488 65 net/eth.c Ethernet found.
2490 -80 common/cmd_net.c usage wrong
2491 80 common/cmd_net.c before calling net_loop()
2492 -81 common/cmd_net.c some error in net_loop() occurred
2493 81 common/cmd_net.c net_loop() back without error
2494 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2495 82 common/cmd_net.c trying automatic boot
2496 83 common/cmd_net.c running "source" command
2497 -83 common/cmd_net.c some error in automatic boot or "source" command
2498 84 common/cmd_net.c end without errors
2503 100 common/cmd_bootm.c Kernel FIT Image has correct format
2504 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2505 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2506 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2507 102 common/cmd_bootm.c Kernel unit name specified
2508 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2509 103 common/cmd_bootm.c Found configuration node
2510 104 common/cmd_bootm.c Got kernel subimage node offset
2511 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2512 105 common/cmd_bootm.c Kernel subimage hash verification OK
2513 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2514 106 common/cmd_bootm.c Architecture check OK
2515 -106 common/cmd_bootm.c Kernel subimage has wrong type
2516 107 common/cmd_bootm.c Kernel subimage type OK
2517 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2518 108 common/cmd_bootm.c Got kernel subimage data/size
2519 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2520 -109 common/cmd_bootm.c Can't get kernel subimage type
2521 -110 common/cmd_bootm.c Can't get kernel subimage comp
2522 -111 common/cmd_bootm.c Can't get kernel subimage os
2523 -112 common/cmd_bootm.c Can't get kernel subimage load address
2524 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2526 120 common/image.c Start initial ramdisk verification
2527 -120 common/image.c Ramdisk FIT image has incorrect format
2528 121 common/image.c Ramdisk FIT image has correct format
2529 122 common/image.c No ramdisk subimage unit name, using configuration
2530 -122 common/image.c Can't get configuration for ramdisk subimage
2531 123 common/image.c Ramdisk unit name specified
2532 -124 common/image.c Can't get ramdisk subimage node offset
2533 125 common/image.c Got ramdisk subimage node offset
2534 -125 common/image.c Ramdisk subimage hash verification failed
2535 126 common/image.c Ramdisk subimage hash verification OK
2536 -126 common/image.c Ramdisk subimage for unsupported architecture
2537 127 common/image.c Architecture check OK
2538 -127 common/image.c Can't get ramdisk subimage data/size
2539 128 common/image.c Got ramdisk subimage data/size
2540 129 common/image.c Can't get ramdisk load address
2541 -129 common/image.c Got ramdisk load address
2543 -130 common/cmd_doc.c Incorrect FIT image format
2544 131 common/cmd_doc.c FIT image format OK
2546 -140 common/cmd_ide.c Incorrect FIT image format
2547 141 common/cmd_ide.c FIT image format OK
2549 -150 common/cmd_nand.c Incorrect FIT image format
2550 151 common/cmd_nand.c FIT image format OK
2552 - legacy image format:
2553 CONFIG_IMAGE_FORMAT_LEGACY
2554 enables the legacy image format support in U-Boot.
2557 enabled if CONFIG_FIT_SIGNATURE is not defined.
2559 CONFIG_DISABLE_IMAGE_LEGACY
2560 disable the legacy image format
2562 This define is introduced, as the legacy image format is
2563 enabled per default for backward compatibility.
2565 - Standalone program support:
2566 CONFIG_STANDALONE_LOAD_ADDR
2568 This option defines a board specific value for the
2569 address where standalone program gets loaded, thus
2570 overwriting the architecture dependent default
2573 - Frame Buffer Address:
2576 Define CONFIG_FB_ADDR if you want to use specific
2577 address for frame buffer. This is typically the case
2578 when using a graphics controller has separate video
2579 memory. U-Boot will then place the frame buffer at
2580 the given address instead of dynamically reserving it
2581 in system RAM by calling lcd_setmem(), which grabs
2582 the memory for the frame buffer depending on the
2583 configured panel size.
2585 Please see board_init_f function.
2587 - Automatic software updates via TFTP server
2589 CONFIG_UPDATE_TFTP_CNT_MAX
2590 CONFIG_UPDATE_TFTP_MSEC_MAX
2592 These options enable and control the auto-update feature;
2593 for a more detailed description refer to doc/README.update.
2595 - MTD Support (mtdparts command, UBI support)
2598 Adds the MTD device infrastructure from the Linux kernel.
2599 Needed for mtdparts command support.
2601 CONFIG_MTD_PARTITIONS
2603 Adds the MTD partitioning infrastructure from the Linux
2604 kernel. Needed for UBI support.
2607 CONFIG_UBI_SILENCE_MSG
2609 Make the verbose messages from UBI stop printing. This leaves
2610 warnings and errors enabled.
2613 CONFIG_MTD_UBI_WL_THRESHOLD
2614 This parameter defines the maximum difference between the highest
2615 erase counter value and the lowest erase counter value of eraseblocks
2616 of UBI devices. When this threshold is exceeded, UBI starts performing
2617 wear leveling by means of moving data from eraseblock with low erase
2618 counter to eraseblocks with high erase counter.
2620 The default value should be OK for SLC NAND flashes, NOR flashes and
2621 other flashes which have eraseblock life-cycle 100000 or more.
2622 However, in case of MLC NAND flashes which typically have eraseblock
2623 life-cycle less than 10000, the threshold should be lessened (e.g.,
2624 to 128 or 256, although it does not have to be power of 2).
2628 CONFIG_MTD_UBI_BEB_LIMIT
2629 This option specifies the maximum bad physical eraseblocks UBI
2630 expects on the MTD device (per 1024 eraseblocks). If the
2631 underlying flash does not admit of bad eraseblocks (e.g. NOR
2632 flash), this value is ignored.
2634 NAND datasheets often specify the minimum and maximum NVM
2635 (Number of Valid Blocks) for the flashes' endurance lifetime.
2636 The maximum expected bad eraseblocks per 1024 eraseblocks
2637 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2638 which gives 20 for most NANDs (MaxNVB is basically the total
2639 count of eraseblocks on the chip).
2641 To put it differently, if this value is 20, UBI will try to
2642 reserve about 1.9% of physical eraseblocks for bad blocks
2643 handling. And that will be 1.9% of eraseblocks on the entire
2644 NAND chip, not just the MTD partition UBI attaches. This means
2645 that if you have, say, a NAND flash chip admits maximum 40 bad
2646 eraseblocks, and it is split on two MTD partitions of the same
2647 size, UBI will reserve 40 eraseblocks when attaching a
2652 CONFIG_MTD_UBI_FASTMAP
2653 Fastmap is a mechanism which allows attaching an UBI device
2654 in nearly constant time. Instead of scanning the whole MTD device it
2655 only has to locate a checkpoint (called fastmap) on the device.
2656 The on-flash fastmap contains all information needed to attach
2657 the device. Using fastmap makes only sense on large devices where
2658 attaching by scanning takes long. UBI will not automatically install
2659 a fastmap on old images, but you can set the UBI parameter
2660 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2661 that fastmap-enabled images are still usable with UBI implementations
2662 without fastmap support. On typical flash devices the whole fastmap
2663 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2665 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2666 Set this parameter to enable fastmap automatically on images
2670 CONFIG_MTD_UBI_FM_DEBUG
2671 Enable UBI fastmap debug
2675 CONFIG_UBIFS_SILENCE_MSG
2677 Make the verbose messages from UBIFS stop printing. This leaves
2678 warnings and errors enabled.
2682 Enable building of SPL globally.
2685 LDSCRIPT for linking the SPL binary.
2687 CONFIG_SPL_MAX_FOOTPRINT
2688 Maximum size in memory allocated to the SPL, BSS included.
2689 When defined, the linker checks that the actual memory
2690 used by SPL from _start to __bss_end does not exceed it.
2691 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2692 must not be both defined at the same time.
2695 Maximum size of the SPL image (text, data, rodata, and
2696 linker lists sections), BSS excluded.
2697 When defined, the linker checks that the actual size does
2700 CONFIG_SPL_TEXT_BASE
2701 TEXT_BASE for linking the SPL binary.
2703 CONFIG_SPL_RELOC_TEXT_BASE
2704 Address to relocate to. If unspecified, this is equal to
2705 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2707 CONFIG_SPL_BSS_START_ADDR
2708 Link address for the BSS within the SPL binary.
2710 CONFIG_SPL_BSS_MAX_SIZE
2711 Maximum size in memory allocated to the SPL BSS.
2712 When defined, the linker checks that the actual memory used
2713 by SPL from __bss_start to __bss_end does not exceed it.
2714 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2715 must not be both defined at the same time.
2718 Adress of the start of the stack SPL will use
2720 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2721 When defined, SPL will panic() if the image it has
2722 loaded does not have a signature.
2723 Defining this is useful when code which loads images
2724 in SPL cannot guarantee that absolutely all read errors
2726 An example is the LPC32XX MLC NAND driver, which will
2727 consider that a completely unreadable NAND block is bad,
2728 and thus should be skipped silently.
2730 CONFIG_SPL_RELOC_STACK
2731 Adress of the start of the stack SPL will use after
2732 relocation. If unspecified, this is equal to
2735 CONFIG_SYS_SPL_MALLOC_START
2736 Starting address of the malloc pool used in SPL.
2737 When this option is set the full malloc is used in SPL and
2738 it is set up by spl_init() and before that, the simple malloc()
2739 can be used if CONFIG_SYS_MALLOC_F is defined.
2741 CONFIG_SYS_SPL_MALLOC_SIZE
2742 The size of the malloc pool used in SPL.
2744 CONFIG_SPL_FRAMEWORK
2745 Enable the SPL framework under common/. This framework
2746 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2747 NAND loading of the Linux Kernel.
2750 Enable booting directly to an OS from SPL.
2751 See also: doc/README.falcon
2753 CONFIG_SPL_DISPLAY_PRINT
2754 For ARM, enable an optional function to print more information
2755 about the running system.
2757 CONFIG_SPL_INIT_MINIMAL
2758 Arch init code should be built for a very small image
2760 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2761 Partition on the MMC to load U-Boot from when the MMC is being
2764 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2765 Sector to load kernel uImage from when MMC is being
2766 used in raw mode (for Falcon mode)
2768 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2769 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2770 Sector and number of sectors to load kernel argument
2771 parameters from when MMC is being used in raw mode
2774 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2775 Partition on the MMC to load U-Boot from when the MMC is being
2778 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2779 Filename to read to load U-Boot when reading from filesystem
2781 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2782 Filename to read to load kernel uImage when reading
2783 from filesystem (for Falcon mode)
2785 CONFIG_SPL_FS_LOAD_ARGS_NAME
2786 Filename to read to load kernel argument parameters
2787 when reading from filesystem (for Falcon mode)
2789 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2790 Set this for NAND SPL on PPC mpc83xx targets, so that
2791 start.S waits for the rest of the SPL to load before
2792 continuing (the hardware starts execution after just
2793 loading the first page rather than the full 4K).
2795 CONFIG_SPL_SKIP_RELOCATE
2796 Avoid SPL relocation
2798 CONFIG_SPL_NAND_BASE
2799 Include nand_base.c in the SPL. Requires
2800 CONFIG_SPL_NAND_DRIVERS.
2802 CONFIG_SPL_NAND_DRIVERS
2803 SPL uses normal NAND drivers, not minimal drivers.
2806 Include standard software ECC in the SPL
2808 CONFIG_SPL_NAND_SIMPLE
2809 Support for NAND boot using simple NAND drivers that
2810 expose the cmd_ctrl() interface.
2813 Support for a lightweight UBI (fastmap) scanner and
2816 CONFIG_SPL_NAND_RAW_ONLY
2817 Support to boot only raw u-boot.bin images. Use this only
2818 if you need to save space.
2820 CONFIG_SPL_COMMON_INIT_DDR
2821 Set for common ddr init with serial presence detect in
2824 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2825 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2826 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2827 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2828 CONFIG_SYS_NAND_ECCBYTES
2829 Defines the size and behavior of the NAND that SPL uses
2832 CONFIG_SPL_NAND_BOOT
2833 Add support NAND boot
2835 CONFIG_SYS_NAND_U_BOOT_OFFS
2836 Location in NAND to read U-Boot from
2838 CONFIG_SYS_NAND_U_BOOT_DST
2839 Location in memory to load U-Boot to
2841 CONFIG_SYS_NAND_U_BOOT_SIZE
2842 Size of image to load
2844 CONFIG_SYS_NAND_U_BOOT_START
2845 Entry point in loaded image to jump to
2847 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2848 Define this if you need to first read the OOB and then the
2849 data. This is used, for example, on davinci platforms.
2851 CONFIG_SPL_RAM_DEVICE
2852 Support for running image already present in ram, in SPL binary
2855 Image offset to which the SPL should be padded before appending
2856 the SPL payload. By default, this is defined as
2857 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2858 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2859 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2862 Final target image containing SPL and payload. Some SPLs
2863 use an arch-specific makefile fragment instead, for
2864 example if more than one image needs to be produced.
2866 CONFIG_FIT_SPL_PRINT
2867 Printing information about a FIT image adds quite a bit of
2868 code to SPL. So this is normally disabled in SPL. Use this
2869 option to re-enable it. This will affect the output of the
2870 bootm command when booting a FIT image.
2874 Enable building of TPL globally.
2877 Image offset to which the TPL should be padded before appending
2878 the TPL payload. By default, this is defined as
2879 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2880 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2881 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2883 - Interrupt support (PPC):
2885 There are common interrupt_init() and timer_interrupt()
2886 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2887 for CPU specific initialization. interrupt_init_cpu()
2888 should set decrementer_count to appropriate value. If
2889 CPU resets decrementer automatically after interrupt
2890 (ppc4xx) it should set decrementer_count to zero.
2891 timer_interrupt() calls timer_interrupt_cpu() for CPU
2892 specific handling. If board has watchdog / status_led
2893 / other_activity_monitor it works automatically from
2894 general timer_interrupt().
2897 Board initialization settings:
2898 ------------------------------
2900 During Initialization u-boot calls a number of board specific functions
2901 to allow the preparation of board specific prerequisites, e.g. pin setup
2902 before drivers are initialized. To enable these callbacks the
2903 following configuration macros have to be defined. Currently this is
2904 architecture specific, so please check arch/your_architecture/lib/board.c
2905 typically in board_init_f() and board_init_r().
2907 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2908 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2909 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2910 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2912 Configuration Settings:
2913 -----------------------
2915 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
2916 Optionally it can be defined to support 64-bit memory commands.
2918 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2919 undefine this when you're short of memory.
2921 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2922 width of the commands listed in the 'help' command output.
2924 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2925 prompt for user input.
2927 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2929 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2931 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2933 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2934 the application (usually a Linux kernel) when it is
2937 - CONFIG_SYS_BAUDRATE_TABLE:
2938 List of legal baudrate settings for this board.
2940 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2941 Begin and End addresses of the area used by the
2944 - CONFIG_SYS_ALT_MEMTEST:
2945 Enable an alternate, more extensive memory test.
2947 - CONFIG_SYS_MEMTEST_SCRATCH:
2948 Scratch address used by the alternate memory test
2949 You only need to set this if address zero isn't writeable
2951 - CONFIG_SYS_MEM_RESERVE_SECURE
2952 Only implemented for ARMv8 for now.
2953 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
2954 is substracted from total RAM and won't be reported to OS.
2955 This memory can be used as secure memory. A variable
2956 gd->arch.secure_ram is used to track the location. In systems
2957 the RAM base is not zero, or RAM is divided into banks,
2958 this variable needs to be recalcuated to get the address.
2960 - CONFIG_SYS_MEM_TOP_HIDE:
2961 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2962 this specified memory area will get subtracted from the top
2963 (end) of RAM and won't get "touched" at all by U-Boot. By
2964 fixing up gd->ram_size the Linux kernel should gets passed
2965 the now "corrected" memory size and won't touch it either.
2966 This should work for arch/ppc and arch/powerpc. Only Linux
2967 board ports in arch/powerpc with bootwrapper support that
2968 recalculate the memory size from the SDRAM controller setup
2969 will have to get fixed in Linux additionally.
2971 This option can be used as a workaround for the 440EPx/GRx
2972 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2975 WARNING: Please make sure that this value is a multiple of
2976 the Linux page size (normally 4k). If this is not the case,
2977 then the end address of the Linux memory will be located at a
2978 non page size aligned address and this could cause major
2981 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2982 Enable temporary baudrate change while serial download
2984 - CONFIG_SYS_SDRAM_BASE:
2985 Physical start address of SDRAM. _Must_ be 0 here.
2987 - CONFIG_SYS_FLASH_BASE:
2988 Physical start address of Flash memory.
2990 - CONFIG_SYS_MONITOR_BASE:
2991 Physical start address of boot monitor code (set by
2992 make config files to be same as the text base address
2993 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2994 CONFIG_SYS_FLASH_BASE when booting from flash.
2996 - CONFIG_SYS_MONITOR_LEN:
2997 Size of memory reserved for monitor code, used to
2998 determine _at_compile_time_ (!) if the environment is
2999 embedded within the U-Boot image, or in a separate
3002 - CONFIG_SYS_MALLOC_LEN:
3003 Size of DRAM reserved for malloc() use.
3005 - CONFIG_SYS_MALLOC_F_LEN
3006 Size of the malloc() pool for use before relocation. If
3007 this is defined, then a very simple malloc() implementation
3008 will become available before relocation. The address is just
3009 below the global data, and the stack is moved down to make
3012 This feature allocates regions with increasing addresses
3013 within the region. calloc() is supported, but realloc()
3014 is not available. free() is supported but does nothing.
3015 The memory will be freed (or in fact just forgotten) when
3016 U-Boot relocates itself.
3018 - CONFIG_SYS_MALLOC_SIMPLE
3019 Provides a simple and small malloc() and calloc() for those
3020 boards which do not use the full malloc in SPL (which is
3021 enabled with CONFIG_SYS_SPL_MALLOC_START).
3023 - CONFIG_SYS_NONCACHED_MEMORY:
3024 Size of non-cached memory area. This area of memory will be
3025 typically located right below the malloc() area and mapped
3026 uncached in the MMU. This is useful for drivers that would
3027 otherwise require a lot of explicit cache maintenance. For
3028 some drivers it's also impossible to properly maintain the
3029 cache. For example if the regions that need to be flushed
3030 are not a multiple of the cache-line size, *and* padding
3031 cannot be allocated between the regions to align them (i.e.
3032 if the HW requires a contiguous array of regions, and the
3033 size of each region is not cache-aligned), then a flush of
3034 one region may result in overwriting data that hardware has
3035 written to another region in the same cache-line. This can
3036 happen for example in network drivers where descriptors for
3037 buffers are typically smaller than the CPU cache-line (e.g.
3038 16 bytes vs. 32 or 64 bytes).
3040 Non-cached memory is only supported on 32-bit ARM at present.
3042 - CONFIG_SYS_BOOTM_LEN:
3043 Normally compressed uImages are limited to an
3044 uncompressed size of 8 MBytes. If this is not enough,
3045 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3046 to adjust this setting to your needs.
3048 - CONFIG_SYS_BOOTMAPSZ:
3049 Maximum size of memory mapped by the startup code of
3050 the Linux kernel; all data that must be processed by
3051 the Linux kernel (bd_info, boot arguments, FDT blob if
3052 used) must be put below this limit, unless "bootm_low"
3053 environment variable is defined and non-zero. In such case
3054 all data for the Linux kernel must be between "bootm_low"
3055 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3056 variable "bootm_mapsize" will override the value of
3057 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3058 then the value in "bootm_size" will be used instead.
3060 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3061 Enable initrd_high functionality. If defined then the
3062 initrd_high feature is enabled and the bootm ramdisk subcommand
3065 - CONFIG_SYS_BOOT_GET_CMDLINE:
3066 Enables allocating and saving kernel cmdline in space between
3067 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3069 - CONFIG_SYS_BOOT_GET_KBD:
3070 Enables allocating and saving a kernel copy of the bd_info in
3071 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3073 - CONFIG_SYS_MAX_FLASH_BANKS:
3074 Max number of Flash memory banks
3076 - CONFIG_SYS_MAX_FLASH_SECT:
3077 Max number of sectors on a Flash chip
3079 - CONFIG_SYS_FLASH_ERASE_TOUT:
3080 Timeout for Flash erase operations (in ms)
3082 - CONFIG_SYS_FLASH_WRITE_TOUT:
3083 Timeout for Flash write operations (in ms)
3085 - CONFIG_SYS_FLASH_LOCK_TOUT
3086 Timeout for Flash set sector lock bit operation (in ms)
3088 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3089 Timeout for Flash clear lock bits operation (in ms)
3091 - CONFIG_SYS_FLASH_PROTECTION
3092 If defined, hardware flash sectors protection is used
3093 instead of U-Boot software protection.
3095 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3097 Enable TFTP transfers directly to flash memory;
3098 without this option such a download has to be
3099 performed in two steps: (1) download to RAM, and (2)
3100 copy from RAM to flash.
3102 The two-step approach is usually more reliable, since
3103 you can check if the download worked before you erase
3104 the flash, but in some situations (when system RAM is
3105 too limited to allow for a temporary copy of the
3106 downloaded image) this option may be very useful.
3108 - CONFIG_SYS_FLASH_CFI:
3109 Define if the flash driver uses extra elements in the
3110 common flash structure for storing flash geometry.
3112 - CONFIG_FLASH_CFI_DRIVER
3113 This option also enables the building of the cfi_flash driver
3114 in the drivers directory
3116 - CONFIG_FLASH_CFI_MTD
3117 This option enables the building of the cfi_mtd driver
3118 in the drivers directory. The driver exports CFI flash
3121 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3122 Use buffered writes to flash.
3124 - CONFIG_FLASH_SPANSION_S29WS_N
3125 s29ws-n MirrorBit flash has non-standard addresses for buffered
3128 - CONFIG_SYS_FLASH_QUIET_TEST
3129 If this option is defined, the common CFI flash doesn't
3130 print it's warning upon not recognized FLASH banks. This
3131 is useful, if some of the configured banks are only
3132 optionally available.
3134 - CONFIG_FLASH_SHOW_PROGRESS
3135 If defined (must be an integer), print out countdown
3136 digits and dots. Recommended value: 45 (9..1) for 80
3137 column displays, 15 (3..1) for 40 column displays.
3139 - CONFIG_FLASH_VERIFY
3140 If defined, the content of the flash (destination) is compared
3141 against the source after the write operation. An error message
3142 will be printed when the contents are not identical.
3143 Please note that this option is useless in nearly all cases,
3144 since such flash programming errors usually are detected earlier
3145 while unprotecting/erasing/programming. Please only enable
3146 this option if you really know what you are doing.
3148 - CONFIG_SYS_RX_ETH_BUFFER:
3149 Defines the number of Ethernet receive buffers. On some
3150 Ethernet controllers it is recommended to set this value
3151 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3152 buffers can be full shortly after enabling the interface
3153 on high Ethernet traffic.
3154 Defaults to 4 if not defined.
3156 - CONFIG_ENV_MAX_ENTRIES
3158 Maximum number of entries in the hash table that is used
3159 internally to store the environment settings. The default
3160 setting is supposed to be generous and should work in most
3161 cases. This setting can be used to tune behaviour; see
3162 lib/hashtable.c for details.
3164 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3165 - CONFIG_ENV_FLAGS_LIST_STATIC
3166 Enable validation of the values given to environment variables when
3167 calling env set. Variables can be restricted to only decimal,
3168 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3169 the variables can also be restricted to IP address or MAC address.
3171 The format of the list is:
3172 type_attribute = [s|d|x|b|i|m]
3173 access_attribute = [a|r|o|c]
3174 attributes = type_attribute[access_attribute]
3175 entry = variable_name[:attributes]
3178 The type attributes are:
3179 s - String (default)
3182 b - Boolean ([1yYtT|0nNfF])
3186 The access attributes are:
3192 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3193 Define this to a list (string) to define the ".flags"
3194 environment variable in the default or embedded environment.
3196 - CONFIG_ENV_FLAGS_LIST_STATIC
3197 Define this to a list (string) to define validation that
3198 should be done if an entry is not found in the ".flags"
3199 environment variable. To override a setting in the static
3200 list, simply add an entry for the same variable name to the
3203 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3204 regular expression. This allows multiple variables to define the same
3205 flags without explicitly listing them for each variable.
3207 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3208 If defined, don't allow the -f switch to env set override variable
3212 If stdint.h is available with your toolchain you can define this
3213 option to enable it. You can provide option 'USE_STDINT=1' when
3214 building U-Boot to enable this.
3216 The following definitions that deal with the placement and management
3217 of environment data (variable area); in general, we support the
3218 following configurations:
3220 - CONFIG_BUILD_ENVCRC:
3222 Builds up envcrc with the target environment so that external utils
3223 may easily extract it and embed it in final U-Boot images.
3225 BE CAREFUL! The first access to the environment happens quite early
3226 in U-Boot initialization (when we try to get the setting of for the
3227 console baudrate). You *MUST* have mapped your NVRAM area then, or
3230 Please note that even with NVRAM we still use a copy of the
3231 environment in RAM: we could work on NVRAM directly, but we want to
3232 keep settings there always unmodified except somebody uses "saveenv"
3233 to save the current settings.
3235 BE CAREFUL! For some special cases, the local device can not use
3236 "saveenv" command. For example, the local device will get the
3237 environment stored in a remote NOR flash by SRIO or PCIE link,
3238 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3240 - CONFIG_NAND_ENV_DST
3242 Defines address in RAM to which the nand_spl code should copy the
3243 environment. If redundant environment is used, it will be copied to
3244 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3246 Please note that the environment is read-only until the monitor
3247 has been relocated to RAM and a RAM copy of the environment has been
3248 created; also, when using EEPROM you will have to use env_get_f()
3249 until then to read environment variables.
3251 The environment is protected by a CRC32 checksum. Before the monitor
3252 is relocated into RAM, as a result of a bad CRC you will be working
3253 with the compiled-in default environment - *silently*!!! [This is
3254 necessary, because the first environment variable we need is the
3255 "baudrate" setting for the console - if we have a bad CRC, we don't
3256 have any device yet where we could complain.]
3258 Note: once the monitor has been relocated, then it will complain if
3259 the default environment is used; a new CRC is computed as soon as you
3260 use the "saveenv" command to store a valid environment.
3262 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3263 Echo the inverted Ethernet link state to the fault LED.
3265 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3266 also needs to be defined.
3268 - CONFIG_SYS_FAULT_MII_ADDR:
3269 MII address of the PHY to check for the Ethernet link state.
3271 - CONFIG_NS16550_MIN_FUNCTIONS:
3272 Define this if you desire to only have use of the NS16550_init
3273 and NS16550_putc functions for the serial driver located at
3274 drivers/serial/ns16550.c. This option is useful for saving
3275 space for already greatly restricted images, including but not
3276 limited to NAND_SPL configurations.
3278 - CONFIG_DISPLAY_BOARDINFO
3279 Display information about the board that U-Boot is running on
3280 when U-Boot starts up. The board function checkboard() is called
3283 - CONFIG_DISPLAY_BOARDINFO_LATE
3284 Similar to the previous option, but display this information
3285 later, once stdio is running and output goes to the LCD, if
3288 - CONFIG_BOARD_SIZE_LIMIT:
3289 Maximum size of the U-Boot image. When defined, the
3290 build system checks that the actual size does not
3293 Low Level (hardware related) configuration options:
3294 ---------------------------------------------------
3296 - CONFIG_SYS_CACHELINE_SIZE:
3297 Cache Line Size of the CPU.
3299 - CONFIG_SYS_CCSRBAR_DEFAULT:
3300 Default (power-on reset) physical address of CCSR on Freescale
3303 - CONFIG_SYS_CCSRBAR:
3304 Virtual address of CCSR. On a 32-bit build, this is typically
3305 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3307 - CONFIG_SYS_CCSRBAR_PHYS:
3308 Physical address of CCSR. CCSR can be relocated to a new
3309 physical address, if desired. In this case, this macro should
3310 be set to that address. Otherwise, it should be set to the
3311 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3312 is typically relocated on 36-bit builds. It is recommended
3313 that this macro be defined via the _HIGH and _LOW macros:
3315 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3316 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3318 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3319 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3320 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3321 used in assembly code, so it must not contain typecasts or
3322 integer size suffixes (e.g. "ULL").
3324 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3325 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3326 used in assembly code, so it must not contain typecasts or
3327 integer size suffixes (e.g. "ULL").
3329 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3330 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3331 forced to a value that ensures that CCSR is not relocated.
3333 - Floppy Disk Support:
3334 CONFIG_SYS_FDC_DRIVE_NUMBER
3336 the default drive number (default value 0)
3338 CONFIG_SYS_ISA_IO_STRIDE
3340 defines the spacing between FDC chipset registers
3343 CONFIG_SYS_ISA_IO_OFFSET
3345 defines the offset of register from address. It
3346 depends on which part of the data bus is connected to
3347 the FDC chipset. (default value 0)
3349 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3350 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3353 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3354 fdc_hw_init() is called at the beginning of the FDC
3355 setup. fdc_hw_init() must be provided by the board
3356 source code. It is used to make hardware-dependent
3360 Most IDE controllers were designed to be connected with PCI
3361 interface. Only few of them were designed for AHB interface.
3362 When software is doing ATA command and data transfer to
3363 IDE devices through IDE-AHB controller, some additional
3364 registers accessing to these kind of IDE-AHB controller
3367 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3368 DO NOT CHANGE unless you know exactly what you're
3369 doing! (11-4) [MPC8xx systems only]
3371 - CONFIG_SYS_INIT_RAM_ADDR:
3373 Start address of memory area that can be used for
3374 initial data and stack; please note that this must be
3375 writable memory that is working WITHOUT special
3376 initialization, i. e. you CANNOT use normal RAM which
3377 will become available only after programming the
3378 memory controller and running certain initialization
3381 U-Boot uses the following memory types:
3382 - MPC8xx: IMMR (internal memory of the CPU)
3384 - CONFIG_SYS_GBL_DATA_OFFSET:
3386 Offset of the initial data structure in the memory
3387 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3388 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3389 data is located at the end of the available space
3390 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3391 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3392 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3393 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3396 On the MPC824X (or other systems that use the data
3397 cache for initial memory) the address chosen for
3398 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3399 point to an otherwise UNUSED address space between
3400 the top of RAM and the start of the PCI space.
3402 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3404 - CONFIG_SYS_OR_TIMING_SDRAM:
3407 - CONFIG_SYS_MAMR_PTA:
3408 periodic timer for refresh
3410 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3411 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3412 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3413 CONFIG_SYS_BR1_PRELIM:
3414 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3416 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3417 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3418 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3419 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3421 - CONFIG_PCI_ENUM_ONLY
3422 Only scan through and get the devices on the buses.
3423 Don't do any setup work, presumably because someone or
3424 something has already done it, and we don't need to do it
3425 a second time. Useful for platforms that are pre-booted
3426 by coreboot or similar.
3428 - CONFIG_PCI_INDIRECT_BRIDGE:
3429 Enable support for indirect PCI bridges.
3432 Chip has SRIO or not
3435 Board has SRIO 1 port available
3438 Board has SRIO 2 port available
3440 - CONFIG_SRIO_PCIE_BOOT_MASTER
3441 Board can support master function for Boot from SRIO and PCIE
3443 - CONFIG_SYS_SRIOn_MEM_VIRT:
3444 Virtual Address of SRIO port 'n' memory region
3446 - CONFIG_SYS_SRIOn_MEM_PHYS:
3447 Physical Address of SRIO port 'n' memory region
3449 - CONFIG_SYS_SRIOn_MEM_SIZE:
3450 Size of SRIO port 'n' memory region
3452 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3453 Defined to tell the NAND controller that the NAND chip is using
3455 Not all NAND drivers use this symbol.
3456 Example of drivers that use it:
3457 - drivers/mtd/nand/ndfc.c
3458 - drivers/mtd/nand/mxc_nand.c
3460 - CONFIG_SYS_NDFC_EBC0_CFG
3461 Sets the EBC0_CFG register for the NDFC. If not defined
3462 a default value will be used.
3465 Get DDR timing information from an I2C EEPROM. Common
3466 with pluggable memory modules such as SODIMMs
3469 I2C address of the SPD EEPROM
3471 - CONFIG_SYS_SPD_BUS_NUM
3472 If SPD EEPROM is on an I2C bus other than the first
3473 one, specify here. Note that the value must resolve
3474 to something your driver can deal with.
3476 - CONFIG_SYS_DDR_RAW_TIMING
3477 Get DDR timing information from other than SPD. Common with
3478 soldered DDR chips onboard without SPD. DDR raw timing
3479 parameters are extracted from datasheet and hard-coded into
3480 header files or board specific files.
3482 - CONFIG_FSL_DDR_INTERACTIVE
3483 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3485 - CONFIG_FSL_DDR_SYNC_REFRESH
3486 Enable sync of refresh for multiple controllers.
3488 - CONFIG_FSL_DDR_BIST
3489 Enable built-in memory test for Freescale DDR controllers.
3491 - CONFIG_SYS_83XX_DDR_USES_CS0
3492 Only for 83xx systems. If specified, then DDR should
3493 be configured using CS0 and CS1 instead of CS2 and CS3.
3496 Enable RMII mode for all FECs.
3497 Note that this is a global option, we can't
3498 have one FEC in standard MII mode and another in RMII mode.
3500 - CONFIG_CRC32_VERIFY
3501 Add a verify option to the crc32 command.
3504 => crc32 -v <address> <count> <crc32>
3506 Where address/count indicate a memory area
3507 and crc32 is the correct crc32 which the
3511 Add the "loopw" memory command. This only takes effect if
3512 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3515 Add the "mdc" and "mwc" memory commands. These are cyclic
3520 This command will print 4 bytes (10,11,12,13) each 500 ms.
3522 => mwc.l 100 12345678 10
3523 This command will write 12345678 to address 100 all 10 ms.
3525 This only takes effect if the memory commands are activated
3526 globally (CONFIG_CMD_MEMORY).
3528 - CONFIG_SKIP_LOWLEVEL_INIT
3529 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3530 low level initializations (like setting up the memory
3531 controller) are omitted and/or U-Boot does not
3532 relocate itself into RAM.
3534 Normally this variable MUST NOT be defined. The only
3535 exception is when U-Boot is loaded (to RAM) by some
3536 other boot loader or by a debugger which performs
3537 these initializations itself.
3539 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3540 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3541 to be skipped. The normal CP15 init (such as enabling the
3542 instruction cache) is still performed.
3545 Modifies the behaviour of start.S when compiling a loader
3546 that is executed before the actual U-Boot. E.g. when
3547 compiling a NAND SPL.
3550 Modifies the behaviour of start.S when compiling a loader
3551 that is executed after the SPL and before the actual U-Boot.
3552 It is loaded by the SPL.
3554 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3555 Only for 85xx systems. If this variable is specified, the section
3556 .resetvec is not kept and the section .bootpg is placed in the
3557 previous 4k of the .text section.
3559 - CONFIG_ARCH_MAP_SYSMEM
3560 Generally U-Boot (and in particular the md command) uses
3561 effective address. It is therefore not necessary to regard
3562 U-Boot address as virtual addresses that need to be translated
3563 to physical addresses. However, sandbox requires this, since
3564 it maintains its own little RAM buffer which contains all
3565 addressable memory. This option causes some memory accesses
3566 to be mapped through map_sysmem() / unmap_sysmem().
3568 - CONFIG_X86_RESET_VECTOR
3569 If defined, the x86 reset vector code is included. This is not
3570 needed when U-Boot is running from Coreboot.
3572 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3573 Enables the RTC32K OSC on AM33xx based plattforms
3575 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3576 Option to disable subpage write in NAND driver
3577 driver that uses this:
3578 drivers/mtd/nand/davinci_nand.c
3580 Freescale QE/FMAN Firmware Support:
3581 -----------------------------------
3583 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3584 loading of "firmware", which is encoded in the QE firmware binary format.
3585 This firmware often needs to be loaded during U-Boot booting, so macros
3586 are used to identify the storage device (NOR flash, SPI, etc) and the address
3589 - CONFIG_SYS_FMAN_FW_ADDR
3590 The address in the storage device where the FMAN microcode is located. The
3591 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3594 - CONFIG_SYS_QE_FW_ADDR
3595 The address in the storage device where the QE microcode is located. The
3596 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3599 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3600 The maximum possible size of the firmware. The firmware binary format
3601 has a field that specifies the actual size of the firmware, but it
3602 might not be possible to read any part of the firmware unless some
3603 local storage is allocated to hold the entire firmware first.
3605 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3606 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3607 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3608 virtual address in NOR flash.
3610 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3611 Specifies that QE/FMAN firmware is located in NAND flash.
3612 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3614 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3615 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3616 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3618 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3619 Specifies that QE/FMAN firmware is located in the remote (master)
3620 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3621 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3622 window->master inbound window->master LAW->the ucode address in
3623 master's memory space.
3625 Freescale Layerscape Management Complex Firmware Support:
3626 ---------------------------------------------------------
3627 The Freescale Layerscape Management Complex (MC) supports the loading of
3629 This firmware often needs to be loaded during U-Boot booting, so macros
3630 are used to identify the storage device (NOR flash, SPI, etc) and the address
3633 - CONFIG_FSL_MC_ENET
3634 Enable the MC driver for Layerscape SoCs.
3636 Freescale Layerscape Debug Server Support:
3637 -------------------------------------------
3638 The Freescale Layerscape Debug Server Support supports the loading of
3639 "Debug Server firmware" and triggering SP boot-rom.
3640 This firmware often needs to be loaded during U-Boot booting.
3642 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3643 Define alignment of reserved memory MC requires
3648 In order to achieve reproducible builds, timestamps used in the U-Boot build
3649 process have to be set to a fixed value.
3651 This is done using the SOURCE_DATE_EPOCH environment variable.
3652 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3653 option for U-Boot or an environment variable in U-Boot.
3655 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3657 Building the Software:
3658 ======================
3660 Building U-Boot has been tested in several native build environments
3661 and in many different cross environments. Of course we cannot support
3662 all possibly existing versions of cross development tools in all
3663 (potentially obsolete) versions. In case of tool chain problems we
3664 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3665 which is extensively used to build and test U-Boot.
3667 If you are not using a native environment, it is assumed that you
3668 have GNU cross compiling tools available in your path. In this case,
3669 you must set the environment variable CROSS_COMPILE in your shell.
3670 Note that no changes to the Makefile or any other source files are
3671 necessary. For example using the ELDK on a 4xx CPU, please enter:
3673 $ CROSS_COMPILE=ppc_4xx-
3674 $ export CROSS_COMPILE
3676 Note: If you wish to generate Windows versions of the utilities in
3677 the tools directory you can use the MinGW toolchain
3678 (http://www.mingw.org). Set your HOST tools to the MinGW
3679 toolchain and execute 'make tools'. For example:
3681 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3683 Binaries such as tools/mkimage.exe will be created which can
3684 be executed on computers running Windows.
3686 U-Boot is intended to be simple to build. After installing the
3687 sources you must configure U-Boot for one specific board type. This
3692 where "NAME_defconfig" is the name of one of the existing configu-
3693 rations; see boards.cfg for supported names.
3695 Note: for some board special configuration names may exist; check if
3696 additional information is available from the board vendor; for
3697 instance, the TQM823L systems are available without (standard)
3698 or with LCD support. You can select such additional "features"
3699 when choosing the configuration, i. e.
3701 make TQM823L_defconfig
3702 - will configure for a plain TQM823L, i. e. no LCD support
3704 make TQM823L_LCD_defconfig
3705 - will configure for a TQM823L with U-Boot console on LCD
3710 Finally, type "make all", and you should get some working U-Boot
3711 images ready for download to / installation on your system:
3713 - "u-boot.bin" is a raw binary image
3714 - "u-boot" is an image in ELF binary format
3715 - "u-boot.srec" is in Motorola S-Record format
3717 By default the build is performed locally and the objects are saved
3718 in the source directory. One of the two methods can be used to change
3719 this behavior and build U-Boot to some external directory:
3721 1. Add O= to the make command line invocations:
3723 make O=/tmp/build distclean
3724 make O=/tmp/build NAME_defconfig
3725 make O=/tmp/build all
3727 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3729 export KBUILD_OUTPUT=/tmp/build
3734 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3738 Please be aware that the Makefiles assume you are using GNU make, so
3739 for instance on NetBSD you might need to use "gmake" instead of
3743 If the system board that you have is not listed, then you will need
3744 to port U-Boot to your hardware platform. To do this, follow these
3747 1. Create a new directory to hold your board specific code. Add any
3748 files you need. In your board directory, you will need at least
3749 the "Makefile" and a "<board>.c".
3750 2. Create a new configuration file "include/configs/<board>.h" for
3752 3. If you're porting U-Boot to a new CPU, then also create a new
3753 directory to hold your CPU specific code. Add any files you need.
3754 4. Run "make <board>_defconfig" with your new name.
3755 5. Type "make", and you should get a working "u-boot.srec" file
3756 to be installed on your target system.
3757 6. Debug and solve any problems that might arise.
3758 [Of course, this last step is much harder than it sounds.]
3761 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3762 ==============================================================
3764 If you have modified U-Boot sources (for instance added a new board
3765 or support for new devices, a new CPU, etc.) you are expected to
3766 provide feedback to the other developers. The feedback normally takes
3767 the form of a "patch", i. e. a context diff against a certain (latest
3768 official or latest in the git repository) version of U-Boot sources.
3770 But before you submit such a patch, please verify that your modifi-
3771 cation did not break existing code. At least make sure that *ALL* of
3772 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3773 just run the buildman script (tools/buildman/buildman), which will
3774 configure and build U-Boot for ALL supported system. Be warned, this
3775 will take a while. Please see the buildman README, or run 'buildman -H'
3779 See also "U-Boot Porting Guide" below.
3782 Monitor Commands - Overview:
3783 ============================
3785 go - start application at address 'addr'
3786 run - run commands in an environment variable
3787 bootm - boot application image from memory
3788 bootp - boot image via network using BootP/TFTP protocol
3789 bootz - boot zImage from memory
3790 tftpboot- boot image via network using TFTP protocol
3791 and env variables "ipaddr" and "serverip"
3792 (and eventually "gatewayip")
3793 tftpput - upload a file via network using TFTP protocol
3794 rarpboot- boot image via network using RARP/TFTP protocol
3795 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3796 loads - load S-Record file over serial line
3797 loadb - load binary file over serial line (kermit mode)
3799 mm - memory modify (auto-incrementing)
3800 nm - memory modify (constant address)
3801 mw - memory write (fill)
3803 cmp - memory compare
3804 crc32 - checksum calculation
3805 i2c - I2C sub-system
3806 sspi - SPI utility commands
3807 base - print or set address offset
3808 printenv- print environment variables
3809 setenv - set environment variables
3810 saveenv - save environment variables to persistent storage
3811 protect - enable or disable FLASH write protection
3812 erase - erase FLASH memory
3813 flinfo - print FLASH memory information
3814 nand - NAND memory operations (see doc/README.nand)
3815 bdinfo - print Board Info structure
3816 iminfo - print header information for application image
3817 coninfo - print console devices and informations
3818 ide - IDE sub-system
3819 loop - infinite loop on address range
3820 loopw - infinite write loop on address range
3821 mtest - simple RAM test
3822 icache - enable or disable instruction cache
3823 dcache - enable or disable data cache
3824 reset - Perform RESET of the CPU
3825 echo - echo args to console
3826 version - print monitor version
3827 help - print online help
3828 ? - alias for 'help'
3831 Monitor Commands - Detailed Description:
3832 ========================================
3836 For now: just type "help <command>".
3839 Environment Variables:
3840 ======================
3842 U-Boot supports user configuration using Environment Variables which
3843 can be made persistent by saving to Flash memory.
3845 Environment Variables are set using "setenv", printed using
3846 "printenv", and saved to Flash using "saveenv". Using "setenv"
3847 without a value can be used to delete a variable from the
3848 environment. As long as you don't save the environment you are
3849 working with an in-memory copy. In case the Flash area containing the
3850 environment is erased by accident, a default environment is provided.
3852 Some configuration options can be set using Environment Variables.
3854 List of environment variables (most likely not complete):
3856 baudrate - see CONFIG_BAUDRATE
3858 bootdelay - see CONFIG_BOOTDELAY
3860 bootcmd - see CONFIG_BOOTCOMMAND
3862 bootargs - Boot arguments when booting an RTOS image
3864 bootfile - Name of the image to load with TFTP
3866 bootm_low - Memory range available for image processing in the bootm
3867 command can be restricted. This variable is given as
3868 a hexadecimal number and defines lowest address allowed
3869 for use by the bootm command. See also "bootm_size"
3870 environment variable. Address defined by "bootm_low" is
3871 also the base of the initial memory mapping for the Linux
3872 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3875 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3876 This variable is given as a hexadecimal number and it
3877 defines the size of the memory region starting at base
3878 address bootm_low that is accessible by the Linux kernel
3879 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3880 as the default value if it is defined, and bootm_size is
3883 bootm_size - Memory range available for image processing in the bootm
3884 command can be restricted. This variable is given as
3885 a hexadecimal number and defines the size of the region
3886 allowed for use by the bootm command. See also "bootm_low"
3887 environment variable.
3889 updatefile - Location of the software update file on a TFTP server, used
3890 by the automatic software update feature. Please refer to
3891 documentation in doc/README.update for more details.
3893 autoload - if set to "no" (any string beginning with 'n'),
3894 "bootp" will just load perform a lookup of the
3895 configuration from the BOOTP server, but not try to
3896 load any image using TFTP
3898 autostart - if set to "yes", an image loaded using the "bootp",
3899 "rarpboot", "tftpboot" or "diskboot" commands will
3900 be automatically started (by internally calling
3903 If set to "no", a standalone image passed to the
3904 "bootm" command will be copied to the load address
3905 (and eventually uncompressed), but NOT be started.
3906 This can be used to load and uncompress arbitrary
3909 fdt_high - if set this restricts the maximum address that the
3910 flattened device tree will be copied into upon boot.
3911 For example, if you have a system with 1 GB memory
3912 at physical address 0x10000000, while Linux kernel
3913 only recognizes the first 704 MB as low memory, you
3914 may need to set fdt_high as 0x3C000000 to have the
3915 device tree blob be copied to the maximum address
3916 of the 704 MB low memory, so that Linux kernel can
3917 access it during the boot procedure.
3919 If this is set to the special value 0xFFFFFFFF then
3920 the fdt will not be copied at all on boot. For this
3921 to work it must reside in writable memory, have
3922 sufficient padding on the end of it for u-boot to
3923 add the information it needs into it, and the memory
3924 must be accessible by the kernel.
3926 fdtcontroladdr- if set this is the address of the control flattened
3927 device tree used by U-Boot when CONFIG_OF_CONTROL is
3930 i2cfast - (PPC405GP|PPC405EP only)
3931 if set to 'y' configures Linux I2C driver for fast
3932 mode (400kHZ). This environment variable is used in
3933 initialization code. So, for changes to be effective
3934 it must be saved and board must be reset.
3936 initrd_high - restrict positioning of initrd images:
3937 If this variable is not set, initrd images will be
3938 copied to the highest possible address in RAM; this
3939 is usually what you want since it allows for
3940 maximum initrd size. If for some reason you want to
3941 make sure that the initrd image is loaded below the
3942 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3943 variable to a value of "no" or "off" or "0".
3944 Alternatively, you can set it to a maximum upper
3945 address to use (U-Boot will still check that it
3946 does not overwrite the U-Boot stack and data).
3948 For instance, when you have a system with 16 MB
3949 RAM, and want to reserve 4 MB from use by Linux,
3950 you can do this by adding "mem=12M" to the value of
3951 the "bootargs" variable. However, now you must make
3952 sure that the initrd image is placed in the first
3953 12 MB as well - this can be done with
3955 setenv initrd_high 00c00000
3957 If you set initrd_high to 0xFFFFFFFF, this is an
3958 indication to U-Boot that all addresses are legal
3959 for the Linux kernel, including addresses in flash
3960 memory. In this case U-Boot will NOT COPY the
3961 ramdisk at all. This may be useful to reduce the
3962 boot time on your system, but requires that this
3963 feature is supported by your Linux kernel.
3965 ipaddr - IP address; needed for tftpboot command
3967 loadaddr - Default load address for commands like "bootp",
3968 "rarpboot", "tftpboot", "loadb" or "diskboot"
3970 loads_echo - see CONFIG_LOADS_ECHO
3972 serverip - TFTP server IP address; needed for tftpboot command
3974 bootretry - see CONFIG_BOOT_RETRY_TIME
3976 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3978 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3980 ethprime - controls which interface is used first.
3982 ethact - controls which interface is currently active.
3983 For example you can do the following
3985 => setenv ethact FEC
3986 => ping 192.168.0.1 # traffic sent on FEC
3987 => setenv ethact SCC
3988 => ping 10.0.0.1 # traffic sent on SCC
3990 ethrotate - When set to "no" U-Boot does not go through all
3991 available network interfaces.
3992 It just stays at the currently selected interface.
3994 netretry - When set to "no" each network operation will
3995 either succeed or fail without retrying.
3996 When set to "once" the network operation will
3997 fail when all the available network interfaces
3998 are tried once without success.
3999 Useful on scripts which control the retry operation
4002 npe_ucode - set load address for the NPE microcode
4004 silent_linux - If set then Linux will be told to boot silently, by
4005 changing the console to be empty. If "yes" it will be
4006 made silent. If "no" it will not be made silent. If
4007 unset, then it will be made silent if the U-Boot console
4010 tftpsrcp - If this is set, the value is used for TFTP's
4013 tftpdstp - If this is set, the value is used for TFTP's UDP
4014 destination port instead of the Well Know Port 69.
4016 tftpblocksize - Block size to use for TFTP transfers; if not set,
4017 we use the TFTP server's default block size
4019 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4020 seconds, minimum value is 1000 = 1 second). Defines
4021 when a packet is considered to be lost so it has to
4022 be retransmitted. The default is 5000 = 5 seconds.
4023 Lowering this value may make downloads succeed
4024 faster in networks with high packet loss rates or
4025 with unreliable TFTP servers.
4027 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4028 unit, minimum value = 0). Defines how many timeouts
4029 can happen during a single file transfer before that
4030 transfer is aborted. The default is 10, and 0 means
4031 'no timeouts allowed'. Increasing this value may help
4032 downloads succeed with high packet loss rates, or with
4033 unreliable TFTP servers or client hardware.
4035 vlan - When set to a value < 4095 the traffic over
4036 Ethernet is encapsulated/received over 802.1q
4039 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4040 Unsigned value, in milliseconds. If not set, the period will
4041 be either the default (28000), or a value based on
4042 CONFIG_NET_RETRY_COUNT, if defined. This value has
4043 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4045 The following image location variables contain the location of images
4046 used in booting. The "Image" column gives the role of the image and is
4047 not an environment variable name. The other columns are environment
4048 variable names. "File Name" gives the name of the file on a TFTP
4049 server, "RAM Address" gives the location in RAM the image will be
4050 loaded to, and "Flash Location" gives the image's address in NOR
4051 flash or offset in NAND flash.
4053 *Note* - these variables don't have to be defined for all boards, some
4054 boards currently use other variables for these purposes, and some
4055 boards use these variables for other purposes.
4057 Image File Name RAM Address Flash Location
4058 ----- --------- ----------- --------------
4059 u-boot u-boot u-boot_addr_r u-boot_addr
4060 Linux kernel bootfile kernel_addr_r kernel_addr
4061 device tree blob fdtfile fdt_addr_r fdt_addr
4062 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4064 The following environment variables may be used and automatically
4065 updated by the network boot commands ("bootp" and "rarpboot"),
4066 depending the information provided by your boot server:
4068 bootfile - see above
4069 dnsip - IP address of your Domain Name Server
4070 dnsip2 - IP address of your secondary Domain Name Server
4071 gatewayip - IP address of the Gateway (Router) to use
4072 hostname - Target hostname
4074 netmask - Subnet Mask
4075 rootpath - Pathname of the root filesystem on the NFS server
4076 serverip - see above
4079 There are two special Environment Variables:
4081 serial# - contains hardware identification information such
4082 as type string and/or serial number
4083 ethaddr - Ethernet address
4085 These variables can be set only once (usually during manufacturing of
4086 the board). U-Boot refuses to delete or overwrite these variables
4087 once they have been set once.
4090 Further special Environment Variables:
4092 ver - Contains the U-Boot version string as printed
4093 with the "version" command. This variable is
4094 readonly (see CONFIG_VERSION_VARIABLE).
4097 Please note that changes to some configuration parameters may take
4098 only effect after the next boot (yes, that's just like Windoze :-).
4101 Callback functions for environment variables:
4102 ---------------------------------------------
4104 For some environment variables, the behavior of u-boot needs to change
4105 when their values are changed. This functionality allows functions to
4106 be associated with arbitrary variables. On creation, overwrite, or
4107 deletion, the callback will provide the opportunity for some side
4108 effect to happen or for the change to be rejected.
4110 The callbacks are named and associated with a function using the
4111 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4113 These callbacks are associated with variables in one of two ways. The
4114 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4115 in the board configuration to a string that defines a list of
4116 associations. The list must be in the following format:
4118 entry = variable_name[:callback_name]
4121 If the callback name is not specified, then the callback is deleted.
4122 Spaces are also allowed anywhere in the list.
4124 Callbacks can also be associated by defining the ".callbacks" variable
4125 with the same list format above. Any association in ".callbacks" will
4126 override any association in the static list. You can define
4127 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4128 ".callbacks" environment variable in the default or embedded environment.
4130 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4131 regular expression. This allows multiple variables to be connected to
4132 the same callback without explicitly listing them all out.
4135 Command Line Parsing:
4136 =====================
4138 There are two different command line parsers available with U-Boot:
4139 the old "simple" one, and the much more powerful "hush" shell:
4141 Old, simple command line parser:
4142 --------------------------------
4144 - supports environment variables (through setenv / saveenv commands)
4145 - several commands on one line, separated by ';'
4146 - variable substitution using "... ${name} ..." syntax
4147 - special characters ('$', ';') can be escaped by prefixing with '\',
4149 setenv bootcmd bootm \${address}
4150 - You can also escape text by enclosing in single apostrophes, for example:
4151 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4156 - similar to Bourne shell, with control structures like
4157 if...then...else...fi, for...do...done; while...do...done,
4158 until...do...done, ...
4159 - supports environment ("global") variables (through setenv / saveenv
4160 commands) and local shell variables (through standard shell syntax
4161 "name=value"); only environment variables can be used with "run"
4167 (1) If a command line (or an environment variable executed by a "run"
4168 command) contains several commands separated by semicolon, and
4169 one of these commands fails, then the remaining commands will be
4172 (2) If you execute several variables with one call to run (i. e.
4173 calling run with a list of variables as arguments), any failing
4174 command will cause "run" to terminate, i. e. the remaining
4175 variables are not executed.
4177 Note for Redundant Ethernet Interfaces:
4178 =======================================
4180 Some boards come with redundant Ethernet interfaces; U-Boot supports
4181 such configurations and is capable of automatic selection of a
4182 "working" interface when needed. MAC assignment works as follows:
4184 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4185 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4186 "eth1addr" (=>eth1), "eth2addr", ...
4188 If the network interface stores some valid MAC address (for instance
4189 in SROM), this is used as default address if there is NO correspon-
4190 ding setting in the environment; if the corresponding environment
4191 variable is set, this overrides the settings in the card; that means:
4193 o If the SROM has a valid MAC address, and there is no address in the
4194 environment, the SROM's address is used.
4196 o If there is no valid address in the SROM, and a definition in the
4197 environment exists, then the value from the environment variable is
4200 o If both the SROM and the environment contain a MAC address, and
4201 both addresses are the same, this MAC address is used.
4203 o If both the SROM and the environment contain a MAC address, and the
4204 addresses differ, the value from the environment is used and a
4207 o If neither SROM nor the environment contain a MAC address, an error
4208 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4209 a random, locally-assigned MAC is used.
4211 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4212 will be programmed into hardware as part of the initialization process. This
4213 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4214 The naming convention is as follows:
4215 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4220 U-Boot is capable of booting (and performing other auxiliary operations on)
4221 images in two formats:
4223 New uImage format (FIT)
4224 -----------------------
4226 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4227 to Flattened Device Tree). It allows the use of images with multiple
4228 components (several kernels, ramdisks, etc.), with contents protected by
4229 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4235 Old image format is based on binary files which can be basically anything,
4236 preceded by a special header; see the definitions in include/image.h for
4237 details; basically, the header defines the following image properties:
4239 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4240 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4241 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4242 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4244 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4245 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4246 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4247 * Compression Type (uncompressed, gzip, bzip2)
4253 The header is marked by a special Magic Number, and both the header
4254 and the data portions of the image are secured against corruption by
4261 Although U-Boot should support any OS or standalone application
4262 easily, the main focus has always been on Linux during the design of
4265 U-Boot includes many features that so far have been part of some
4266 special "boot loader" code within the Linux kernel. Also, any
4267 "initrd" images to be used are no longer part of one big Linux image;
4268 instead, kernel and "initrd" are separate images. This implementation
4269 serves several purposes:
4271 - the same features can be used for other OS or standalone
4272 applications (for instance: using compressed images to reduce the
4273 Flash memory footprint)
4275 - it becomes much easier to port new Linux kernel versions because
4276 lots of low-level, hardware dependent stuff are done by U-Boot
4278 - the same Linux kernel image can now be used with different "initrd"
4279 images; of course this also means that different kernel images can
4280 be run with the same "initrd". This makes testing easier (you don't
4281 have to build a new "zImage.initrd" Linux image when you just
4282 change a file in your "initrd"). Also, a field-upgrade of the
4283 software is easier now.
4289 Porting Linux to U-Boot based systems:
4290 ---------------------------------------
4292 U-Boot cannot save you from doing all the necessary modifications to
4293 configure the Linux device drivers for use with your target hardware
4294 (no, we don't intend to provide a full virtual machine interface to
4297 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4299 Just make sure your machine specific header file (for instance
4300 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4301 Information structure as we define in include/asm-<arch>/u-boot.h,
4302 and make sure that your definition of IMAP_ADDR uses the same value
4303 as your U-Boot configuration in CONFIG_SYS_IMMR.
4305 Note that U-Boot now has a driver model, a unified model for drivers.
4306 If you are adding a new driver, plumb it into driver model. If there
4307 is no uclass available, you are encouraged to create one. See
4311 Configuring the Linux kernel:
4312 -----------------------------
4314 No specific requirements for U-Boot. Make sure you have some root
4315 device (initial ramdisk, NFS) for your target system.
4318 Building a Linux Image:
4319 -----------------------
4321 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4322 not used. If you use recent kernel source, a new build target
4323 "uImage" will exist which automatically builds an image usable by
4324 U-Boot. Most older kernels also have support for a "pImage" target,
4325 which was introduced for our predecessor project PPCBoot and uses a
4326 100% compatible format.
4330 make TQM850L_defconfig
4335 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4336 encapsulate a compressed Linux kernel image with header information,
4337 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4339 * build a standard "vmlinux" kernel image (in ELF binary format):
4341 * convert the kernel into a raw binary image:
4343 ${CROSS_COMPILE}-objcopy -O binary \
4344 -R .note -R .comment \
4345 -S vmlinux linux.bin
4347 * compress the binary image:
4351 * package compressed binary image for U-Boot:
4353 mkimage -A ppc -O linux -T kernel -C gzip \
4354 -a 0 -e 0 -n "Linux Kernel Image" \
4355 -d linux.bin.gz uImage
4358 The "mkimage" tool can also be used to create ramdisk images for use
4359 with U-Boot, either separated from the Linux kernel image, or
4360 combined into one file. "mkimage" encapsulates the images with a 64
4361 byte header containing information about target architecture,
4362 operating system, image type, compression method, entry points, time
4363 stamp, CRC32 checksums, etc.
4365 "mkimage" can be called in two ways: to verify existing images and
4366 print the header information, or to build new images.
4368 In the first form (with "-l" option) mkimage lists the information
4369 contained in the header of an existing U-Boot image; this includes
4370 checksum verification:
4372 tools/mkimage -l image
4373 -l ==> list image header information
4375 The second form (with "-d" option) is used to build a U-Boot image
4376 from a "data file" which is used as image payload:
4378 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4379 -n name -d data_file image
4380 -A ==> set architecture to 'arch'
4381 -O ==> set operating system to 'os'
4382 -T ==> set image type to 'type'
4383 -C ==> set compression type 'comp'
4384 -a ==> set load address to 'addr' (hex)
4385 -e ==> set entry point to 'ep' (hex)
4386 -n ==> set image name to 'name'
4387 -d ==> use image data from 'datafile'
4389 Right now, all Linux kernels for PowerPC systems use the same load
4390 address (0x00000000), but the entry point address depends on the
4393 - 2.2.x kernels have the entry point at 0x0000000C,
4394 - 2.3.x and later kernels have the entry point at 0x00000000.
4396 So a typical call to build a U-Boot image would read:
4398 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4399 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4400 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4401 > examples/uImage.TQM850L
4402 Image Name: 2.4.4 kernel for TQM850L
4403 Created: Wed Jul 19 02:34:59 2000
4404 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4405 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4406 Load Address: 0x00000000
4407 Entry Point: 0x00000000
4409 To verify the contents of the image (or check for corruption):
4411 -> tools/mkimage -l examples/uImage.TQM850L
4412 Image Name: 2.4.4 kernel for TQM850L
4413 Created: Wed Jul 19 02:34:59 2000
4414 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4415 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4416 Load Address: 0x00000000
4417 Entry Point: 0x00000000
4419 NOTE: for embedded systems where boot time is critical you can trade
4420 speed for memory and install an UNCOMPRESSED image instead: this
4421 needs more space in Flash, but boots much faster since it does not
4422 need to be uncompressed:
4424 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4425 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4426 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4427 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4428 > examples/uImage.TQM850L-uncompressed
4429 Image Name: 2.4.4 kernel for TQM850L
4430 Created: Wed Jul 19 02:34:59 2000
4431 Image Type: PowerPC Linux Kernel Image (uncompressed)
4432 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4433 Load Address: 0x00000000
4434 Entry Point: 0x00000000
4437 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4438 when your kernel is intended to use an initial ramdisk:
4440 -> tools/mkimage -n 'Simple Ramdisk Image' \
4441 > -A ppc -O linux -T ramdisk -C gzip \
4442 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4443 Image Name: Simple Ramdisk Image
4444 Created: Wed Jan 12 14:01:50 2000
4445 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4446 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4447 Load Address: 0x00000000
4448 Entry Point: 0x00000000
4450 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4451 option performs the converse operation of the mkimage's second form (the "-d"
4452 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4455 tools/dumpimage -i image -T type -p position data_file
4456 -i ==> extract from the 'image' a specific 'data_file'
4457 -T ==> set image type to 'type'
4458 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4461 Installing a Linux Image:
4462 -------------------------
4464 To downloading a U-Boot image over the serial (console) interface,
4465 you must convert the image to S-Record format:
4467 objcopy -I binary -O srec examples/image examples/image.srec
4469 The 'objcopy' does not understand the information in the U-Boot
4470 image header, so the resulting S-Record file will be relative to
4471 address 0x00000000. To load it to a given address, you need to
4472 specify the target address as 'offset' parameter with the 'loads'
4475 Example: install the image to address 0x40100000 (which on the
4476 TQM8xxL is in the first Flash bank):
4478 => erase 40100000 401FFFFF
4484 ## Ready for S-Record download ...
4485 ~>examples/image.srec
4486 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4488 15989 15990 15991 15992
4489 [file transfer complete]
4491 ## Start Addr = 0x00000000
4494 You can check the success of the download using the 'iminfo' command;
4495 this includes a checksum verification so you can be sure no data
4496 corruption happened:
4500 ## Checking Image at 40100000 ...
4501 Image Name: 2.2.13 for initrd on TQM850L
4502 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4503 Data Size: 335725 Bytes = 327 kB = 0 MB
4504 Load Address: 00000000
4505 Entry Point: 0000000c
4506 Verifying Checksum ... OK
4512 The "bootm" command is used to boot an application that is stored in
4513 memory (RAM or Flash). In case of a Linux kernel image, the contents
4514 of the "bootargs" environment variable is passed to the kernel as
4515 parameters. You can check and modify this variable using the
4516 "printenv" and "setenv" commands:
4519 => printenv bootargs
4520 bootargs=root=/dev/ram
4522 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4524 => printenv bootargs
4525 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4528 ## Booting Linux kernel at 40020000 ...
4529 Image Name: 2.2.13 for NFS on TQM850L
4530 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4531 Data Size: 381681 Bytes = 372 kB = 0 MB
4532 Load Address: 00000000
4533 Entry Point: 0000000c
4534 Verifying Checksum ... OK
4535 Uncompressing Kernel Image ... OK
4536 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
4537 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4538 time_init: decrementer frequency = 187500000/60
4539 Calibrating delay loop... 49.77 BogoMIPS
4540 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4543 If you want to boot a Linux kernel with initial RAM disk, you pass
4544 the memory addresses of both the kernel and the initrd image (PPBCOOT
4545 format!) to the "bootm" command:
4547 => imi 40100000 40200000
4549 ## Checking Image at 40100000 ...
4550 Image Name: 2.2.13 for initrd on TQM850L
4551 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4552 Data Size: 335725 Bytes = 327 kB = 0 MB
4553 Load Address: 00000000
4554 Entry Point: 0000000c
4555 Verifying Checksum ... OK
4557 ## Checking Image at 40200000 ...
4558 Image Name: Simple Ramdisk Image
4559 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4560 Data Size: 566530 Bytes = 553 kB = 0 MB
4561 Load Address: 00000000
4562 Entry Point: 00000000
4563 Verifying Checksum ... OK
4565 => bootm 40100000 40200000
4566 ## Booting Linux kernel at 40100000 ...
4567 Image Name: 2.2.13 for initrd on TQM850L
4568 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4569 Data Size: 335725 Bytes = 327 kB = 0 MB
4570 Load Address: 00000000
4571 Entry Point: 0000000c
4572 Verifying Checksum ... OK
4573 Uncompressing Kernel Image ... OK
4574 ## Loading RAMDisk Image at 40200000 ...
4575 Image Name: Simple Ramdisk Image
4576 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4577 Data Size: 566530 Bytes = 553 kB = 0 MB
4578 Load Address: 00000000
4579 Entry Point: 00000000
4580 Verifying Checksum ... OK
4581 Loading Ramdisk ... OK
4582 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
4583 Boot arguments: root=/dev/ram
4584 time_init: decrementer frequency = 187500000/60
4585 Calibrating delay loop... 49.77 BogoMIPS
4587 RAMDISK: Compressed image found at block 0
4588 VFS: Mounted root (ext2 filesystem).
4592 Boot Linux and pass a flat device tree:
4595 First, U-Boot must be compiled with the appropriate defines. See the section
4596 titled "Linux Kernel Interface" above for a more in depth explanation. The
4597 following is an example of how to start a kernel and pass an updated
4603 oft=oftrees/mpc8540ads.dtb
4604 => tftp $oftaddr $oft
4605 Speed: 1000, full duplex
4607 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4608 Filename 'oftrees/mpc8540ads.dtb'.
4609 Load address: 0x300000
4612 Bytes transferred = 4106 (100a hex)
4613 => tftp $loadaddr $bootfile
4614 Speed: 1000, full duplex
4616 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4618 Load address: 0x200000
4619 Loading:############
4621 Bytes transferred = 1029407 (fb51f hex)
4626 => bootm $loadaddr - $oftaddr
4627 ## Booting image at 00200000 ...
4628 Image Name: Linux-2.6.17-dirty
4629 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4630 Data Size: 1029343 Bytes = 1005.2 kB
4631 Load Address: 00000000
4632 Entry Point: 00000000
4633 Verifying Checksum ... OK
4634 Uncompressing Kernel Image ... OK
4635 Booting using flat device tree at 0x300000
4636 Using MPC85xx ADS machine description
4637 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4641 More About U-Boot Image Types:
4642 ------------------------------
4644 U-Boot supports the following image types:
4646 "Standalone Programs" are directly runnable in the environment
4647 provided by U-Boot; it is expected that (if they behave
4648 well) you can continue to work in U-Boot after return from
4649 the Standalone Program.
4650 "OS Kernel Images" are usually images of some Embedded OS which
4651 will take over control completely. Usually these programs
4652 will install their own set of exception handlers, device
4653 drivers, set up the MMU, etc. - this means, that you cannot
4654 expect to re-enter U-Boot except by resetting the CPU.
4655 "RAMDisk Images" are more or less just data blocks, and their
4656 parameters (address, size) are passed to an OS kernel that is
4658 "Multi-File Images" contain several images, typically an OS
4659 (Linux) kernel image and one or more data images like
4660 RAMDisks. This construct is useful for instance when you want
4661 to boot over the network using BOOTP etc., where the boot
4662 server provides just a single image file, but you want to get
4663 for instance an OS kernel and a RAMDisk image.
4665 "Multi-File Images" start with a list of image sizes, each
4666 image size (in bytes) specified by an "uint32_t" in network
4667 byte order. This list is terminated by an "(uint32_t)0".
4668 Immediately after the terminating 0 follow the images, one by
4669 one, all aligned on "uint32_t" boundaries (size rounded up to
4670 a multiple of 4 bytes).
4672 "Firmware Images" are binary images containing firmware (like
4673 U-Boot or FPGA images) which usually will be programmed to
4676 "Script files" are command sequences that will be executed by
4677 U-Boot's command interpreter; this feature is especially
4678 useful when you configure U-Boot to use a real shell (hush)
4679 as command interpreter.
4681 Booting the Linux zImage:
4682 -------------------------
4684 On some platforms, it's possible to boot Linux zImage. This is done
4685 using the "bootz" command. The syntax of "bootz" command is the same
4686 as the syntax of "bootm" command.
4688 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4689 kernel with raw initrd images. The syntax is slightly different, the
4690 address of the initrd must be augmented by it's size, in the following
4691 format: "<initrd addres>:<initrd size>".
4697 One of the features of U-Boot is that you can dynamically load and
4698 run "standalone" applications, which can use some resources of
4699 U-Boot like console I/O functions or interrupt services.
4701 Two simple examples are included with the sources:
4706 'examples/hello_world.c' contains a small "Hello World" Demo
4707 application; it is automatically compiled when you build U-Boot.
4708 It's configured to run at address 0x00040004, so you can play with it
4712 ## Ready for S-Record download ...
4713 ~>examples/hello_world.srec
4714 1 2 3 4 5 6 7 8 9 10 11 ...
4715 [file transfer complete]
4717 ## Start Addr = 0x00040004
4719 => go 40004 Hello World! This is a test.
4720 ## Starting application at 0x00040004 ...
4731 Hit any key to exit ...
4733 ## Application terminated, rc = 0x0
4735 Another example, which demonstrates how to register a CPM interrupt
4736 handler with the U-Boot code, can be found in 'examples/timer.c'.
4737 Here, a CPM timer is set up to generate an interrupt every second.
4738 The interrupt service routine is trivial, just printing a '.'
4739 character, but this is just a demo program. The application can be
4740 controlled by the following keys:
4742 ? - print current values og the CPM Timer registers
4743 b - enable interrupts and start timer
4744 e - stop timer and disable interrupts
4745 q - quit application
4748 ## Ready for S-Record download ...
4749 ~>examples/timer.srec
4750 1 2 3 4 5 6 7 8 9 10 11 ...
4751 [file transfer complete]
4753 ## Start Addr = 0x00040004
4756 ## Starting application at 0x00040004 ...
4759 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4762 [q, b, e, ?] Set interval 1000000 us
4765 [q, b, e, ?] ........
4766 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4769 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4772 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4775 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4777 [q, b, e, ?] ...Stopping timer
4779 [q, b, e, ?] ## Application terminated, rc = 0x0
4785 Over time, many people have reported problems when trying to use the
4786 "minicom" terminal emulation program for serial download. I (wd)
4787 consider minicom to be broken, and recommend not to use it. Under
4788 Unix, I recommend to use C-Kermit for general purpose use (and
4789 especially for kermit binary protocol download ("loadb" command), and
4790 use "cu" for S-Record download ("loads" command). See
4791 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4792 for help with kermit.
4795 Nevertheless, if you absolutely want to use it try adding this
4796 configuration to your "File transfer protocols" section:
4798 Name Program Name U/D FullScr IO-Red. Multi
4799 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4800 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4806 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4807 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4809 Building requires a cross environment; it is known to work on
4810 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4811 need gmake since the Makefiles are not compatible with BSD make).
4812 Note that the cross-powerpc package does not install include files;
4813 attempting to build U-Boot will fail because <machine/ansi.h> is
4814 missing. This file has to be installed and patched manually:
4816 # cd /usr/pkg/cross/powerpc-netbsd/include
4818 # ln -s powerpc machine
4819 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4820 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4822 Native builds *don't* work due to incompatibilities between native
4823 and U-Boot include files.
4825 Booting assumes that (the first part of) the image booted is a
4826 stage-2 loader which in turn loads and then invokes the kernel
4827 proper. Loader sources will eventually appear in the NetBSD source
4828 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4829 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4832 Implementation Internals:
4833 =========================
4835 The following is not intended to be a complete description of every
4836 implementation detail. However, it should help to understand the
4837 inner workings of U-Boot and make it easier to port it to custom
4841 Initial Stack, Global Data:
4842 ---------------------------
4844 The implementation of U-Boot is complicated by the fact that U-Boot
4845 starts running out of ROM (flash memory), usually without access to
4846 system RAM (because the memory controller is not initialized yet).
4847 This means that we don't have writable Data or BSS segments, and BSS
4848 is not initialized as zero. To be able to get a C environment working
4849 at all, we have to allocate at least a minimal stack. Implementation
4850 options for this are defined and restricted by the CPU used: Some CPU
4851 models provide on-chip memory (like the IMMR area on MPC8xx and
4852 MPC826x processors), on others (parts of) the data cache can be
4853 locked as (mis-) used as memory, etc.
4855 Chris Hallinan posted a good summary of these issues to the
4856 U-Boot mailing list:
4858 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4859 From: "Chris Hallinan" <clh@net1plus.com>
4860 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4863 Correct me if I'm wrong, folks, but the way I understand it
4864 is this: Using DCACHE as initial RAM for Stack, etc, does not
4865 require any physical RAM backing up the cache. The cleverness
4866 is that the cache is being used as a temporary supply of
4867 necessary storage before the SDRAM controller is setup. It's
4868 beyond the scope of this list to explain the details, but you
4869 can see how this works by studying the cache architecture and
4870 operation in the architecture and processor-specific manuals.
4872 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4873 is another option for the system designer to use as an
4874 initial stack/RAM area prior to SDRAM being available. Either
4875 option should work for you. Using CS 4 should be fine if your
4876 board designers haven't used it for something that would
4877 cause you grief during the initial boot! It is frequently not
4880 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4881 with your processor/board/system design. The default value
4882 you will find in any recent u-boot distribution in
4883 walnut.h should work for you. I'd set it to a value larger
4884 than your SDRAM module. If you have a 64MB SDRAM module, set
4885 it above 400_0000. Just make sure your board has no resources
4886 that are supposed to respond to that address! That code in
4887 start.S has been around a while and should work as is when
4888 you get the config right.
4893 It is essential to remember this, since it has some impact on the C
4894 code for the initialization procedures:
4896 * Initialized global data (data segment) is read-only. Do not attempt
4899 * Do not use any uninitialized global data (or implicitly initialized
4900 as zero data - BSS segment) at all - this is undefined, initiali-
4901 zation is performed later (when relocating to RAM).
4903 * Stack space is very limited. Avoid big data buffers or things like
4906 Having only the stack as writable memory limits means we cannot use
4907 normal global data to share information between the code. But it
4908 turned out that the implementation of U-Boot can be greatly
4909 simplified by making a global data structure (gd_t) available to all
4910 functions. We could pass a pointer to this data as argument to _all_
4911 functions, but this would bloat the code. Instead we use a feature of
4912 the GCC compiler (Global Register Variables) to share the data: we
4913 place a pointer (gd) to the global data into a register which we
4914 reserve for this purpose.
4916 When choosing a register for such a purpose we are restricted by the
4917 relevant (E)ABI specifications for the current architecture, and by
4918 GCC's implementation.
4920 For PowerPC, the following registers have specific use:
4922 R2: reserved for system use
4923 R3-R4: parameter passing and return values
4924 R5-R10: parameter passing
4925 R13: small data area pointer
4929 (U-Boot also uses R12 as internal GOT pointer. r12
4930 is a volatile register so r12 needs to be reset when
4931 going back and forth between asm and C)
4933 ==> U-Boot will use R2 to hold a pointer to the global data
4935 Note: on PPC, we could use a static initializer (since the
4936 address of the global data structure is known at compile time),
4937 but it turned out that reserving a register results in somewhat
4938 smaller code - although the code savings are not that big (on
4939 average for all boards 752 bytes for the whole U-Boot image,
4940 624 text + 127 data).
4942 On ARM, the following registers are used:
4944 R0: function argument word/integer result
4945 R1-R3: function argument word
4946 R9: platform specific
4947 R10: stack limit (used only if stack checking is enabled)
4948 R11: argument (frame) pointer
4949 R12: temporary workspace
4952 R15: program counter
4954 ==> U-Boot will use R9 to hold a pointer to the global data
4956 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
4958 On Nios II, the ABI is documented here:
4959 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4961 ==> U-Boot will use gp to hold a pointer to the global data
4963 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4964 to access small data sections, so gp is free.
4966 On NDS32, the following registers are used:
4968 R0-R1: argument/return
4970 R15: temporary register for assembler
4971 R16: trampoline register
4972 R28: frame pointer (FP)
4973 R29: global pointer (GP)
4974 R30: link register (LP)
4975 R31: stack pointer (SP)
4976 PC: program counter (PC)
4978 ==> U-Boot will use R10 to hold a pointer to the global data
4980 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4981 or current versions of GCC may "optimize" the code too much.
4986 U-Boot runs in system state and uses physical addresses, i.e. the
4987 MMU is not used either for address mapping nor for memory protection.
4989 The available memory is mapped to fixed addresses using the memory
4990 controller. In this process, a contiguous block is formed for each
4991 memory type (Flash, SDRAM, SRAM), even when it consists of several
4992 physical memory banks.
4994 U-Boot is installed in the first 128 kB of the first Flash bank (on
4995 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4996 booting and sizing and initializing DRAM, the code relocates itself
4997 to the upper end of DRAM. Immediately below the U-Boot code some
4998 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4999 configuration setting]. Below that, a structure with global Board
5000 Info data is placed, followed by the stack (growing downward).
5002 Additionally, some exception handler code is copied to the low 8 kB
5003 of DRAM (0x00000000 ... 0x00001FFF).
5005 So a typical memory configuration with 16 MB of DRAM could look like
5008 0x0000 0000 Exception Vector code
5011 0x0000 2000 Free for Application Use
5017 0x00FB FF20 Monitor Stack (Growing downward)
5018 0x00FB FFAC Board Info Data and permanent copy of global data
5019 0x00FC 0000 Malloc Arena
5022 0x00FE 0000 RAM Copy of Monitor Code
5023 ... eventually: LCD or video framebuffer
5024 ... eventually: pRAM (Protected RAM - unchanged by reset)
5025 0x00FF FFFF [End of RAM]
5028 System Initialization:
5029 ----------------------
5031 In the reset configuration, U-Boot starts at the reset entry point
5032 (on most PowerPC systems at address 0x00000100). Because of the reset
5033 configuration for CS0# this is a mirror of the on board Flash memory.
5034 To be able to re-map memory U-Boot then jumps to its link address.
5035 To be able to implement the initialization code in C, a (small!)
5036 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5037 which provide such a feature like), or in a locked part of the data
5038 cache. After that, U-Boot initializes the CPU core, the caches and
5041 Next, all (potentially) available memory banks are mapped using a
5042 preliminary mapping. For example, we put them on 512 MB boundaries
5043 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5044 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5045 programmed for SDRAM access. Using the temporary configuration, a
5046 simple memory test is run that determines the size of the SDRAM
5049 When there is more than one SDRAM bank, and the banks are of
5050 different size, the largest is mapped first. For equal size, the first
5051 bank (CS2#) is mapped first. The first mapping is always for address
5052 0x00000000, with any additional banks following immediately to create
5053 contiguous memory starting from 0.
5055 Then, the monitor installs itself at the upper end of the SDRAM area
5056 and allocates memory for use by malloc() and for the global Board
5057 Info data; also, the exception vector code is copied to the low RAM
5058 pages, and the final stack is set up.
5060 Only after this relocation will you have a "normal" C environment;
5061 until that you are restricted in several ways, mostly because you are
5062 running from ROM, and because the code will have to be relocated to a
5066 U-Boot Porting Guide:
5067 ----------------------
5069 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5073 int main(int argc, char *argv[])
5075 sighandler_t no_more_time;
5077 signal(SIGALRM, no_more_time);
5078 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5080 if (available_money > available_manpower) {
5081 Pay consultant to port U-Boot;
5085 Download latest U-Boot source;
5087 Subscribe to u-boot mailing list;
5090 email("Hi, I am new to U-Boot, how do I get started?");
5093 Read the README file in the top level directory;
5094 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5095 Read applicable doc/*.README;
5096 Read the source, Luke;
5097 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5100 if (available_money > toLocalCurrency ($2500))
5103 Add a lot of aggravation and time;
5105 if (a similar board exists) { /* hopefully... */
5106 cp -a board/<similar> board/<myboard>
5107 cp include/configs/<similar>.h include/configs/<myboard>.h
5109 Create your own board support subdirectory;
5110 Create your own board include/configs/<myboard>.h file;
5112 Edit new board/<myboard> files
5113 Edit new include/configs/<myboard>.h
5118 Add / modify source code;
5122 email("Hi, I am having problems...");
5124 Send patch file to the U-Boot email list;
5125 if (reasonable critiques)
5126 Incorporate improvements from email list code review;
5128 Defend code as written;
5134 void no_more_time (int sig)
5143 All contributions to U-Boot should conform to the Linux kernel
5144 coding style; see the file "Documentation/CodingStyle" and the script
5145 "scripts/Lindent" in your Linux kernel source directory.
5147 Source files originating from a different project (for example the
5148 MTD subsystem) are generally exempt from these guidelines and are not
5149 reformatted to ease subsequent migration to newer versions of those
5152 Please note that U-Boot is implemented in C (and to some small parts in
5153 Assembler); no C++ is used, so please do not use C++ style comments (//)
5156 Please also stick to the following formatting rules:
5157 - remove any trailing white space
5158 - use TAB characters for indentation and vertical alignment, not spaces
5159 - make sure NOT to use DOS '\r\n' line feeds
5160 - do not add more than 2 consecutive empty lines to source files
5161 - do not add trailing empty lines to source files
5163 Submissions which do not conform to the standards may be returned
5164 with a request to reformat the changes.
5170 Since the number of patches for U-Boot is growing, we need to
5171 establish some rules. Submissions which do not conform to these rules
5172 may be rejected, even when they contain important and valuable stuff.
5174 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5176 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5177 see http://lists.denx.de/mailman/listinfo/u-boot
5179 When you send a patch, please include the following information with
5182 * For bug fixes: a description of the bug and how your patch fixes
5183 this bug. Please try to include a way of demonstrating that the
5184 patch actually fixes something.
5186 * For new features: a description of the feature and your
5189 * A CHANGELOG entry as plaintext (separate from the patch)
5191 * For major contributions, add a MAINTAINERS file with your
5192 information and associated file and directory references.
5194 * When you add support for a new board, don't forget to add a
5195 maintainer e-mail address to the boards.cfg file, too.
5197 * If your patch adds new configuration options, don't forget to
5198 document these in the README file.
5200 * The patch itself. If you are using git (which is *strongly*
5201 recommended) you can easily generate the patch using the
5202 "git format-patch". If you then use "git send-email" to send it to
5203 the U-Boot mailing list, you will avoid most of the common problems
5204 with some other mail clients.
5206 If you cannot use git, use "diff -purN OLD NEW". If your version of
5207 diff does not support these options, then get the latest version of
5210 The current directory when running this command shall be the parent
5211 directory of the U-Boot source tree (i. e. please make sure that
5212 your patch includes sufficient directory information for the
5215 We prefer patches as plain text. MIME attachments are discouraged,
5216 and compressed attachments must not be used.
5218 * If one logical set of modifications affects or creates several
5219 files, all these changes shall be submitted in a SINGLE patch file.
5221 * Changesets that contain different, unrelated modifications shall be
5222 submitted as SEPARATE patches, one patch per changeset.
5227 * Before sending the patch, run the buildman script on your patched
5228 source tree and make sure that no errors or warnings are reported
5229 for any of the boards.
5231 * Keep your modifications to the necessary minimum: A patch
5232 containing several unrelated changes or arbitrary reformats will be
5233 returned with a request to re-formatting / split it.
5235 * If you modify existing code, make sure that your new code does not
5236 add to the memory footprint of the code ;-) Small is beautiful!
5237 When adding new features, these should compile conditionally only
5238 (using #ifdef), and the resulting code with the new feature
5239 disabled must not need more memory than the old code without your
5242 * Remember that there is a size limit of 100 kB per message on the
5243 u-boot mailing list. Bigger patches will be moderated. If they are
5244 reasonable and not too big, they will be acknowledged. But patches
5245 bigger than the size limit should be avoided.